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1.

論文(リポジトリ)

論文(リポジトリ)
小山, 洋司
出版情報: 高知論叢 = 高知論叢.  16  pp.103-139,  1983-03.  高知大学経済学会
本文リンク: http://hdl.handle.net/10191/1283
2.

論文(リポジトリ)

論文(リポジトリ)
稲葉, 一成
出版情報: 秋田県立農業短期大学研究報告 = 秋田県立農業短期大学研究報告.  23  pp.1-23,  1997-08.  秋田県立農業短期大学
本文リンク: http://hdl.handle.net/10191/30512
概要: This paper deals with the stability analyses of landslide slopes by the two-dimensional observations and analyses of groundwater pressure. In the landslide slopes having an inclined groundwater flow or having the multi-stratums with the different coefficients of permeability, the groundwater pressure can not be obtained from the static pressure calculated from the groundwater level since the vertical distribution of the groundwater pressure is not static. In this case, the observations and analyses of groundwater pressure should be considered to be a two-dimensional flow systems in a vertical section. And the distribution of pore water pressure along the slip surface used for the stability analyses should be determined from the water pressure using the finite element solution of groundwater flow. In Higashi-mushigame landslide and Matunoyama-koshi landslide, the groundwater pressures were measured by using the observation boreholes having a screened section not along all its length but only at the desired depth. The numerical models having the multi-stratums with the different coefficients of permeability were by trial and error identified by the finite element method so that the numerical results may agree with these field measurements. The stability analyses of landslide slopes using these distributions of pore water pressure along the slip surface provide the reasonable factors of safety. 続きを見る
3.

論文(リポジトリ)

論文(リポジトリ)
大竹, 芳夫
出版情報: 信州大学教育学部紀要 = 信州大学教育学部紀要.  97  pp.19-30,  1999-08.  信州大学教育学部
本文リンク: http://hdl.handle.net/10191/6441
4.

論文(リポジトリ)

論文(リポジトリ)
村上, 敬宣 ; 児玉, 昭太郎 ; 小沼, 静代
出版情報: 日本機械学会論文集. A編 = 日本機械学会論文集. A編.  54  pp.688-696,  1988-04.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5043
概要: First, the effects of nonmetallic inclusions on the fatique strength of metals are reviewed and the influential factors are revealed. Next, it is emphasized that the effects of nonmetallic inclusions must be analyzed from the viewpoint of small defects or small cracks, because the threshold condition at the fatigue limit is not the condition for crack initiation but the condition for the non-propagation of a crack emanating from defects or inclusions. Finally. from this point of view, the equation for the prediction of the threshold stress intensity factor range ΔK_<th> and fatigue limit σw for defects and small cracks was applied to predict those for inclusions contained in high strength steels. It is demonstrated that the square root of the projected area of inclusions and the H_v of the matrix are the crucial parameters to predict the fatigue limit of metals containing inclusions. The predictions by the proposed equations were in very good agreement with the experimental results obtained from the fracture surface showing fish-eye patterns. The reasons why the fatigue limit σw of high strength steels does not increase linearly with increasing hardness, and why the scatters of fatigue limit are so large are made clear. 続きを見る
5.

論文(リポジトリ)

論文(リポジトリ)
石橋, 達弥 ; 下田, 茂 ; 古川, 徹 ; 新田, 勇 ; 吉田, 秀敏
出版情報: 日本機械学会論文集. A編 = 日本機械学会論文集. A編.  53  pp.2193-2202,  1987-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1768
概要: This study aims at investigating the performance of a hardness testing machine. First, the phenomenon of a contact betwe en a rigid sperical indenter and a plastic material is considered. By using Hertz's elastic contact law, the Young's modulus of plastics Es can be calculated from Eq. (1) using the cordal diameter of an indentation d, the elastic recovery of an indentation δ_r and the indenting load L : E_s = 0.9(3/2) L/(d δ_r)…(1) From the geometrical relation at the contact part, the contacting diameter d_c and the surface level diameter d_l are derived as follows. (δ_t : the total depth) : d_c = 2[D(δ_t-δ_r/2){1-(δ_t-δ_r/2)/D}]^<1/2>…(2), d_l = 2[Dδ_t×(1-δ_t/D)}^<1/2>…(3) Furthermore, the mean strain rate under the elastic recovery by a spherical indenter is related to the strain rate under the uniaxial stress field. Finally, the indenting experiments are carried out, δ_r and δ_t are measured so that a cordal diameter d is formulated as follows : d = d_l{1.71-0.707(d_l/d_c)}…(4) When the Young's moduli calculated from δ_t and δ_r using Eqs. (1)-(4) are compared to the Young's moduli measured from a compression test, their Young's values consist within an accuracy of about ±5-10%. Therefore, the measuring method about Young's modulus of plastics using the indenting hardness test by a spherical indenter can be applied to the present hardness testing machines. 続きを見る
6.

論文(リポジトリ)

論文(リポジトリ)
石橋, 達弥 ; 下田, 茂 ; 古川, 徹 ; 吉田, 秀敏
出版情報: 日本機械学会論文集. A編 = 日本機械学会論文集. A編.  53  pp.637-645,  1987-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1766
概要: Because the theories of rebound hardness suggested until now are based on Meyer's Law which expresses the fully plastic deformation of a specimen under a spherical indenter, the experimental results of impact carried out over a wide range conditions of specimens and indenters can't be explained by it fully and quantitatively. To solve the above points, first the simple theory of rebound hardness is obtained on the basis of three points ; (1) The relative equations of a specimen and a spherical indenter in the elastic-plastic transient indenting process (at the 1st report) are used. (2) To correspond to the various profile of indenters (D type Shore hammer, etc.), the relative equations of rebound energy including the elastic effect of the holding shaft of an indenting sphere (at the 3rd report) are used. (3) The dynamic work necessary to produce a unit volume of the permanent indentation is different quantitatively from the dynamic mean contact pressure. Secondly, the impact experiments are given by the two tip ball type indenters for several specimens, and the necessary expressions are formulated to calculate the concrete values of rebound hardness number. Finally, the experimental results by IIZUKA regarding the influence of the wide conditions of D type Shore hammer on rebound hardness number are quoted and compared with the calculated values using this theory and a good coincidence is obtained between them quantitatively in all points. 続きを見る
7.

論文(リポジトリ)

論文(リポジトリ)
石橋, 達弥 ; 下田, 茂
出版情報: 日本機械学会論文集. A編 = 日本機械学会論文集. A編.  52  pp.2538-2544,  1986-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1770
概要: For the use of a Tip Ball type indenter in the various Rebound Hardness Machines or Methods, it is necessary to investig ate the influence of the holding shaft of an indenting sphere on the relative equations of Rebound Hardness. For this purpose, firstly the Tip Ball type indenter's vibratory system is considered and concluded with the vibratory model of one degree of freedom by the theory of vibration, and shown that in this model, if the ratio of natural period of an indenter to the duration time of impact is very small, the movement of a holding shaft is preportional to the impact force. Therefore the energy stored in a holding shaft during impact can be calculated easily, being equal to the total of this energy and the energy of the contact areas of an indenting sphere and a material using Hertz's Contact Law to the rebound energy of an indenter. The equation of the rebound energy of a Tip Ball type indenter is shown. Next, the results of experiments with several Tip Ball type indenters are given and clarify quantitatively that measured values are consistent with the analyzed values within an accuracy of about ±5% and the influences of a holding shaft are larger as the falling height becomes higher, and the material becomes softer. Finally, the above mentioned points of that influence are confirmed for the Hardness Number by the experiment using the indenter of the D type Shore Hardness Testing Machine. 続きを見る
8.

論文(リポジトリ)

論文(リポジトリ)
石橋, 達弥 ; 下田, 茂
出版情報: 日本機械学会論文集. A編 = 日本機械学会論文集. A編.  52  pp.2387-2394,  1986-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1767
概要: In order to correlate hardness P_m by the spherical indenter with the flow stress Y, it is necessary to determine the to tal mean strain of the indentation, which corresponds to the total strain in a uniaxial stress field. Firstly, the total mean strain of the indentation ε_<ic> is defined, by means of multiplying the total corresponding strain coefficient of the indentation C_<εc> by the total profile coefficient of the indentation (d/D_c) at the end of the plastic flow of a specimen ; ε_<ic>=C_<εc> (d/D_c). Then Hardness/Flow stress ratio C is obtained experimentally, C=9.8 P_m/Y, Y in MPa, and formulated as follows ; C=1.1+(2/3) ln (ε_<ic>・E_s/Y), E_s is the Young's modulus of a specimen. Further, an example of the flow stress-strain characteristic curve of SUS 304 specimen is shown in a wide range of the strain by means of a calculation using this formula and the former reported formula ; P_m=P_<up>(d/D_p)^<xp>, etc.. 続きを見る
9.

論文(リポジトリ)

論文(リポジトリ)
石橋, 達弥 ; 下田, 茂
出版情報: 日本機械学会論文集. A編 = 日本機械学会論文集. A編.  52  pp.1958-1965,  1986-08.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1769
概要: Hardness is influenced by the different mechanical properties of the spherical indenter in the elastic-plastic transient indenting process. To clarify that point, we indented steel and tungsten-carbide spherical indenters in the several standard blocks for hardness. In order to establish the relations of the elastic-plastic transient indenting process experimentally we related the hardness P_m(mean contact pressure) with a true profile coefficient of the permanent indentation : (d/D_p), not with an apparent profile coefficient : (d/D) used traditionally, and formulated as follows ; P_m=P_<up>(d/D_p)^<xp>. We can calculate the hardness affected by the different mechanical properties of the spherical indenter using this formula for arbitrary conditions. Further, we compared the Brinell hardness obtained by Yoshizawa with our calculated values, and we obtained a good coincidence between them. 続きを見る
10.

論文(リポジトリ)

論文(リポジトリ)
藤沢, 延行 ; 渋谷, 賢志 ; 高野, 剛
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  65  pp.3374-3379,  1999-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5762
概要: The flow field around a Darrieus wind turbine is studied by flow visualization and PIV measurement in a rotating frame of reference to understand the unsteady nature of dynamic stall appearing at low tip-speed ratios. The qualitative nature of the dynamic stall observed by the flow visualization using dye injection technique is quantitatively reproduced in the instantaneous velocity distributions around the blade measured by PIV technique. These results indicate that two pairs of stall vortices are generated in one cycle of the turbine rotation and they grow in size as the tip-speed ratio decreases. The mechanism of the dynamic stall is found to be due to the flow separation over the suction side of the blade followed by the generation of in-flow motion from the pressure side to the suction side of the blade through the trailing edge. 続きを見る
11.

論文(リポジトリ)

論文(リポジトリ)
大西, 元 ; 稲岡, 恭二 ; 松原, 幸治 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  65  pp.2077-2084,  1999-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5761
概要: A three dimensional steady numerical analysis has been made for both of staggered array and in-lined array of two-row plate-finned tubes heat exchanger unit located in a uniform flow. The structures of the flow and thermal fields have been examined for conduction-convection conjugate heat transfer problem of the studied fin-and-tube model. The results of the numerical analysis revealed some important effects of geometric parameters on heat transfer from the fin-and-tube surface for each array of two-row tubes. The effects of fin thickness, fin pitch, fin length, tube pitch and Reynolds number on heat exchange rate, Nusselt number, heat transfer rate, and pressure coefficient were examined parametrically. Though space mean Nusselt number and heat transfer rate have no big difference between the two array cases, slightly better heat transfer performance is attained in the staggered array case as Reynolds number or fin pitch is increased. On the contrary, pressure loss obtained in the staggered array case is larger than that obtained in the in-lined array case. 続きを見る
12.

論文(リポジトリ)

論文(リポジトリ)
藤沢, 延行 ; 井上, 智 ; 横田, 正二 ; 田名網, 弘 ; 渡部, 功 ; 高野, 祐二
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  65  pp.48-53,  1999-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5760
概要: Air flows in a heater unit for automobiles are studied by flow visualization with tracer injection technique and the vis ualized images are analyzed by cross correlation method to obtain the velocity distributions in the unit at various mixdoor angles. The results indicate the variations of flow pattern in the heater unit with the mixdoor angles and the appearance of strong interaction between separated main flow and circulating heater flow at relatively large mixdoor angles, which promotes the flow mixing and simultaneously increases the pressure loss inside the unit. The flow fields in the heater unit are calculated numerically based on three dimensional momentum equations combined with κ-ε model of turbulence and with an experimental flow model of heater core. The numerical results reproduce well the experimental flow patterns in the heater unit, but there exits some deviations in the mean velocity and surface pressure distributions at large mixdoor angles. 続きを見る
13.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 松原, 幸治 ; 前川, 博 ; 小川, 豊之
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  64  pp.3801-3807,  1998-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5759
概要: This paper analytically treats of the heat-flow through the periodically varying thermal-resistance thin layer lain betw een conductors or the heat-flow between two periodically contacting conductors. During one cycle of the period, p, thermal-conductance of the thin layer temporally changes in a stepwise profile, and takes two different values, R_c and R_d over the time spans, φp and (1-φ) p, respectively. Analytical solution for the effective thermal-conductance, R_e, of the thin layer was algebraically approximated using R_c, R_d, φ and the harmonic mean, R_<ab>, of the characteristic thermal-conductances of the two conductors. Algebraical approximation was also made for the maximum temperature amplitude, Δθ^*_<max>, arising at the joint ends of conductors. This approximation suggests the following features of Δθ^*_<max>, Δθ^*_<max> takes the maximum value, (Δθ^*_<max>)_<max>, at specified value of φ, φ_<max>, φ_<max> depends only single parameter R_c/R_d, and becomes large with increase of this parameter. On the other hand, (Δθ^*_<max>)_<max> depends not only R_c/R_d but also R_d. 続きを見る
14.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 松原, 幸治 ; 大木, 聡 ; 前川, 博
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  64  pp.2971-2976,  1998-09.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5758
概要: Following the previous works by Maekawa et al. (1991) and Kawada et al. (1991), some turbulence statistics including the triple velocity-temperature correlations were measured in a turbulent boundary layer with a constant temperature for a spanwise direction. Examination was given to the turbulent heat flux budget and also to the reliability of some existing turbulence models. It was revealed that there are remarkable discrepancy between the predicted triple velocity-temperature correlations by the gradient-type model (Launder (1978)) and the experimental result. However, the examination for the turbulent heat flux budget clarified that the budget lies in near local equilibrium except for the near-wall region. Thus, the reliability of the pressure-temperature gradient correlation model is found to be rather important for the prediction of the spanwise turbulent heat flux. The prediction performance of the pressure-temperature gradient correlation model was investigated using two kinds of the models (Launder (1975)), Maekawa et al. (1979). It was found that predicted values by these models show good agreement with the experimental result. 続きを見る
15.

論文(リポジトリ)

論文(リポジトリ)
岩井, 裕 ; 松原, 幸治 ; 中部, 主敬 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  64  pp.1809-1816,  1998-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5757
概要: Three-dimensional numerical simulations were carried out for mixed convective flows over a backward-facing step in a rec tangular duct. Reynolds number, expansion ratio and aspect ratio were kept constant at Re=125,ER=2 and AR=16,respectively. Heat flux at the wall downstream of the step was kept uniform, while other walls were kept at adiabatic condition. Effect of the inclination angles, θ_1,θ_2,was the main objective in this study. It was found that when θ_1 was varied, the effect of buoyancy became prominent at θ_1=0°, 180°, while the effect was relatively small for the two horizontal cases (θ_1=90°, 270°). However, there was still small difference between θ_1=90° and 270° in the region immediately after the step where the flow was relatively slow. When θ_2 was varied, flow and thermal fields could no longer be considered as two dimensional, except when θ_2=-90°, 90°. The maximum Nusselt Number, which appears symmetrically near the side walls in pure forced convection cases, was obtained at only one location close to the lower side wall. 続きを見る
16.

論文(リポジトリ)

論文(リポジトリ)
藤沢, 延行 ; 中林, 貴光 ; 池本, 宏一郎 ; 長屋, 幸助
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  64  pp.1293-1298,  1998-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5756
概要: The active control of vortex shedding from a circular cylinder by rotary ocillations is studied experimentally using neural networks, which optimizes automatically the control parameters such as the phase lag and the feedback coefficient. This optimization procedure is applied to find out an optimum position of reference probe to attenuate the vortex shedding effectively. The attenuation effect of vortex shedding under this control is investigated by measuring the velocity fluctuations in the cylinder wake and the unsteady pressure distributions over the cylinder surface. It is found that the drag and lift forces acting on the cylinder are reduced under the optimum reference control in comparison with the control under other reference positions as well as those of the stationary cylinder. 続きを見る
17.

論文(リポジトリ)

論文(リポジトリ)
松原, 幸治 ; 小林, 睦夫 ; 前川, 博 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  64  pp.856-863,  1998-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5755
概要: Direct numerical simulation was performed for a turbulent channel flow where the time mean temperature has a spanwise gr adient. As the first step of succesive investigations, turbulence statistics related to the spanwise heat transfer were examined. A computational code based on the finite difference scheme was developed for this purpose. The calculated statistics on the flow field were found to be in good agreement with the result of the existing direct numerical simulation by Kasagi et al. (1992). The eddy diffusivity ratio, ε_<nz>/ε_m and the Reynolds normal stress ratio, <ω^2>^^^-/<υ^2>^^^- show rapid increase toward the wall, as pointed out by Maekawa et al. (1991). However, the rapidincrease region of the ε_<nz>/ε_m was nearer to the wall than the Maekwa's result and found to roughly agree with that of the <ω^2>^^^-/<υ^2>^^^-. This result implies that, in the near-wall region, the spanwise turbulent heat flux per its production rate shows rough agreement with the wall-normal turbulent heat flux per its production rate. In addition, two point correlation coefficient, Q_<wθ> also agrees with Q_<vθ> in the range of y^+<75. In these points, the heat transfer in the present case has some analogy with that in the heated-wall case. Moreover, the budget of the spanwise turbulent heat flux was examined. It was found that the budget shows near local equilibrium except for the near-wall region. 続きを見る
18.

論文(リポジトリ)

論文(リポジトリ)
大西, 元 ; 稲岡, 恭二 ; 松原, 幸治 ; 中部, 主敬 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  64  pp.534-541,  1998-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5754
概要: A three dimensional steady numerical analysis has been made for a one unit of single row plate-finned tube heat exchanger located in a uniform flow. The structures of the flow and thermal fields have been examined for conduction-convection conjugate heat transfer problem of the studied fin-and-tube model. The results of the numerical analysis revealed some important effects of geometric parameters on heat transfer from the fin-and-tube surface. The effects of fin thickness, fin pitch, fin length, tube pitch and Reynolds number on Nusselt number, heat transfer rate, fin efficiency and pressure coefficient were examined parametrically. Upstream half of the fin surface yielded a much higher heat transfer coefficient than the downstream half of the fin surface. Especially, the values of fin local heat transfer coefficient is nearly zero in the near region of the tube. As Reynolds number increases, the fin efficiency and the pressure coefficient decrease. 続きを見る
19.

論文(リポジトリ)

論文(リポジトリ)
松原, 幸治 ; 中部, 主敬 ; 鈴木, 健二郎 ; 小林, 睦夫 ; 前川, 博
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  63  pp.3362-3369,  1997-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5753
概要: Two dimensional calculation was performed for combined convection heat transfer in a channel with two ribs attached to o ne wall, following the previous study on forced convection case without buoyancy. The flow is heated from the surfaces of both ribs and the present study dealt with the two cases of buoyancy-assisting flow and buoyancy-opposing flow. The effect of Reynolds number, Re_L, and modified Richardson number, Ri^*, was examined keeping space between ribs, σ, and blockage ratio, τ, constant (σ=3.0,τ=0.5). Increasing the magnitude of buoyancy, unsteady flows predicted by the present calculation are stabilized in both of two cases. Serious deterioration of Nusselt number on the 2nd rib suddenly occurrs in a certain range of Ri^* due to the flow stabilization. This is because flow unsteadiness plays an important roll for heat transfer enhancement as was described in the previous study. However, in buoyancy-assisting flow, similar deterioration of Nusselt number also appears on the 2nd rib even if flow remains steady. This is caused by the disappearance of strong rotating flow which exists in the cavity between the both ribs and keeps fluid in the cavity cooler. 続きを見る
20.

論文(リポジトリ)

論文(リポジトリ)
岩井, 裕 ; 松原, 幸治 ; 中部, 主敬 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  63  pp.2817-2824,  1997-08.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5752
概要: Two-and three-dimensional numerical simulations have been performed for mixed convective upward flows over a backward-facing step in a duct. The Reynolds number, expansion ratio and aspect ratio (in 3D sim.) were kept constant at Re=125,ER=2 and AR=16,respectively. The heat flux at the wall downstream of the step was uniform, while the straight wall, the step and the side walls (in 3D sim.) were assumed to be adiabatic. The effect of the buoyancy level, Ri^*, was the major interest in this study. It was found that the reattachment point and the peak Nusselt number point moved upstream as Ri^* was increased, while the secondary recirculation region, which developed at the corner of the step, became larger. It was also found that there existed a secondary flow in a cross section immediately downstream of the step. Flow directed toward the center of the duct becomes more intensive as Ri^* increases, which possibly results in an increase in the level of three-dimensionality of the flow and thermal fields. 続きを見る
21.

論文(リポジトリ)

論文(リポジトリ)
松原, 幸治 ; 中部, 主敬 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  62  pp.3675-3682,  1996-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5751
概要: Three-dimensional numerical computation was performed for the developing region of flow and thermal fields in finned channels. The channel studied here has a heated region of finite length to which plate fin arrays are attached in order to improve its heat transfer performance. The performance was evaluated using Nu_L^^*, an apparent Nusselt number corresponding to the heat transfer rate per unit heated area. The effect of fin height, fin pitch, fin length and Reynolds number on Nusselt number was examined parametrically. As the fin height increases with the fin pitch kept constant, Nu_L^^* increases monotonically. The maximum value of Nu_L^^* was obtained when the top of the fin reached the top wall of the channel. When the fin pitch was changed with the fin height kept constant, the numerical results demonstrated two tendencies. In the case with clearance between the fin top and the wall, there existed the optimal fin pitch leading to maximum Nu_L^^*. In the case without clearance, Nu_L^^* increases with decrease of fin pitch. The optimal fin pitch gradually decreased with decrease of fin length and/or with increase of Reynolds number. The ratio of the j-factor to the f-factor was also obtained to evaluate the performance of the fins. 続きを見る
22.

論文(リポジトリ)

論文(リポジトリ)
松原, 幸治 ; 中部, 主敬 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  62  pp.2782-2789,  1996-07.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5750
概要: Linear stability analysis was performed for channel flow with two ribs attached to one wall. Effects of perturbations with an infinitely small amplitude on a fundamental steady flow in the channel were numerically investigated. The fundamental flow corresponds to one of the steady solutions of the Navier-Stokes equations. Time-asymptotic solutions of the perturbation equations reach the least stable mode of the channel flow. Growth or decay of the perturbations was supposed to occur everywhere in the flow with a constant amplification factor, since the logarithmic value of the maximum transverse perturbation velocity of the least stable mode changed linearly with time at all monitoring locations in the channel. In addition, a direct numerical calculation was performed using the two-dimensional Navier-Stokes equations to investigate the characteristics of nonlinear stability, the results of which showed a similar growth pattern to those derived from the perturbation equations. The flow instability with an increase of the Reynolds number was found to depend on the value of the source functioning term of the perturbation vorticity equation derived from the perturbation equations. 続きを見る
23.

論文(リポジトリ)

論文(リポジトリ)
方, 義 ; 長谷川, 富市 ; 渡辺, 博 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  62  pp.2151-2155,  1996-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5749
概要: Measurement of drag reduction and frequency analysis of the wall pressure fluctuation in pipe flow are carried out using dilute polymer solutions and aqueous detergent solutions in order to discuss the correlation between drag reduction and pressure fluctuation. Frequency analysis indicates that the power spectrum density of the pressure fluctuation of dilute polymer solutions is greater in the low-frequency region and less above 30[Hz] than that of water (solvent). Moreover, the level of pressure fluctuation in dilute polymer solutions is on the whole greater than that in water. 続きを見る
24.

論文(リポジトリ)

論文(リポジトリ)
中部, 主敬 ; 長谷川, 寛 ; 松原, 幸治 ; 鈴木, 健二郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  62  pp.1937-1944,  1996-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5748
概要: Heating a cylinder should affect the flow pattern around it and the heat transfer from its surface. Numerical computation of the flow and related heat transfer has been carried out for a circular cylinder mounted in a channel flow for a free-forced combined convection regime. In the case that buoyancy assists the flow, the results showed that the transition from unsteady flow to steady flow occurred under different conditions depending on the Ri number, Re number and blockage ratio. With a constant Re number, the critical Ri number at which the transition occurs decreases with increasing blockage ratio, and with a constant Ri number, the transition Re number increases with the blockage ratio. In the case of negative buoyancy, on the other hand, the increase of the Ri number facilitates the growth of the length scale of the Karman vortices. The buoyancy effect on flow instability is less conspicuous compared with that in the above two cases in the case of horizontal flow, but local heat transfer characteristics are still changed by the buoyancy effects. 続きを見る
25.

論文(リポジトリ)

論文(リポジトリ)
関野, 龍男 ; 長谷川, 富市 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  59  pp.2484-2488,  1993-08.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5747
概要: Normal forces generated in the flow between two-rolls, one rotating and the other fixed, are measured. Water and glycerin-water solutions are used in the experiments and the forces measured under the usual experimental condition are in good agreement with one-dimensional theoretical predictions obtained by Cameron using the Reynolds equation and the half Sommerfeld condition. A thin liquid film is produced on the surface of the rotating roll under the usual experimental conditions. But when the liquid film is stripped off with a spatula, the measured normal force is reduced. In the case of a small quantity of supplying fluids and the low speeds of rotating, the measured normal force is negative for water but positive for glycerin-water solutions. 続きを見る
26.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 長谷川, 富市 ; 山根, 隆一郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  58  pp.3522-3530,  1992-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5746
概要: Effects of the stress overshoot on the transmitting force generated in some cases of squeezing flows are analytically in vestigated using a constitutive equation. A nondimensional factor (O_s) that corresponds to the magnitude of the stress overshoot, and an apparent relaxation time (λ_O) are defined by extending the definition in the simple shear flow. The magnitude and the peak time of overshoot in the force induced in normal or reverse squeezing flow are respectively correlated with the O_s and λ_O. In the case of successive squeezing flows consisting of normal squeezing in the first half and reverse squeezing in the second half and vice versa, the force generated in the second squeezing is only dependent on the normalized time t/λ_O. When the two surfaces are subjected to sinusoidal oscillations in the region of high Deborah number, the amplitude of the force and phase lag become large with an increase in O_s, and separating forces time-averaged during the sinusoidal oscillation decrease with an increase in O_s, especially in the extreme case, the two surfaces being forced to approach with sinusoidal oscillation. 続きを見る
27.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 八木, 敏之 ; 長谷川, 富市 ; 山根, 隆一郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  58  pp.1063-1070,  1992-04.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5745
概要: Squeeze film flow between a flat plate and a spherical surface subjected to sinusoidal oscillations is investigated. Transmitting force generated in the squeeze films is measured and calculated with a constitutive equation yielding the stress overshoot and the following results have been obtained: The force measured for Separan solutions oscillates with smaller amplitude than for purely viscous liquids and shows a phase lag in comparison of the force of the viscous liquids. Numerical calculation using the constitutive equation gives guantitative or qualitative agreement with the experimental data for the phase lag or for the amplitude, respectively. The energy dissipated in the Separan solutions in one cycle is less than that evaluated for the purely viscous liquids. An apparent Deborah number respectively correlates to each of the decrease in amplitude, the phase lag and the dissipation of energy taken for various experimental conditions. In the analytical results, an impulse evaluated by integrating the force in one cycle gives a positive value and this means that two surfaces are forced to separate by sinusoidal oscillations. 続きを見る
28.

論文(リポジトリ)

論文(リポジトリ)
反町, 和則 ; 長谷川, 富市
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  58  pp.773-778,  1992-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5743
概要: An experiment has been made on ribbing induced on a film coated over a roll surface in coating by means of a two-roll system, one roll rotating and the other fixed. Wavelength and depth of the ribbing are measured by a newly developed technique utilizing an image reflected on the ribbed film surface by a straight bar, and the following are clarified. Non dimensionalized wavelength is correlated with capillary number for Newtonian liquids, but it takes higher values for several viscoelastic liquids used. Viscoelasticity of the liquid has an effect of increasing the depth of ribbing, that is, the depth takes the value of 0.04mm to 0.1mm for Newtonian liquids, but 0.07mm to 0.2mm for viscoelastic liquids. The wavelength of spatial perturbations generated on the meniscus at the exit of the clearance between the two rolls coincides with the wavelength of the ribbing seen over the roll surface. This means that the perturbation of the liquid generated just after passing through the clearance is carried with rotation of the roll and results in the ribbing over the roll surface. 続きを見る
29.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 高野, 剛 ; 小林, 正人
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  58  pp.857-864,  1992-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5744
概要: Full measurements of thermal field were made for a turbulent flow of air in the entrance section of a two-dimensional curved channel. The wall heat flux develops more rapidly than the mean temperature distribution, decreasing and increasing on the inner and outer walls, respectively. Locations at which the mean temperature gradient and the radial component of turbulent heat flux become zero do not coincide in this case, and the eddy diffusivity of heat becomes negative in a region of about 20% of the channel width. In the vicinity of the wall, the temperature fluctuation intensity normalized by the friction temperature is not affected by the wall curvature, whereas the cross correlation coefficients between velocity and temperature fluctuations, the skewness and the flatness are appreciably affected by it. The triple correlations relating to the transverse diffusion decrease and increase remarkably in the inner and outer sides of the channel, respectively. 続きを見る
30.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 八木, 敏之 ; 長谷川, 富市 ; 山根, 隆一郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  58  pp.441-448,  1992-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5741
概要: In a pool of solution, an upper spherical surface is first approached (or separated) and subsequently made to separate (or approach) relative to a lower flat plate at a constant speed. The transmitted forces are measured, and the following are observed. In the cases of Separan solutions, the measured force overshoots the force estimated by viscous stress at the inception of the subsequent squeezing when a pause time taken in transit between the two squeezing is sufficiently long. However, when the pause time is short, the overshoot in the subsequent squeezing decreases because of an unrelaxed part of the stress produced in the preceding squeezing and the stress generated in the slow squeezing due to the springback of the load cells utilized. If more than 20% of the opposite force evaluated by viscous stress is unrelaxed and left at the inception of the subsequent squeezing, then no overshoot is developed. In the case of PEO solution, whose properties are similar to those of the Separan solution in steady flow, the force measured can be predicted by the viscous stress alone. It is considered that there is a difference between these two solutions in the molecular size of the polymer in water. 続きを見る
31.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 八木, 敏之 ; 長谷川, 富市 ; 山根, 隆一郎
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  58  pp.449-456,  1992-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5742
概要: A constitutive equation yielding the stress overshoot is used in the analysis of the squeezing flow successively generated in the normal and reverse directions. Transmitting forces generated in the flows between a spherical surface and a flat plate are calculated, and the following results are obtained. The contribution of normal stress in the transmitting force is negligible. The transmitting forces analytically obtained can qualitatively show the decrease of overshoot or no overshoot, which is experimentally observed in the subsequent squeezing flow. When the first squeezing is stopped in the midst of an overshoot process and the second reverse one is begun successively, the transmitting force generated in the second reverse squeezing increases more rapidly than the one generated after the overshoot is finished in the first squeezing. 続きを見る
32.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 清水, 康隆 ; 内山, 貢悦
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  58  pp.119-126,  1992-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5740
概要: The space-time correlations and power spectra of velocity fluctuations are measured in two-dimensional turbulent flows through curved and straight channels. Noticeable differences are found between the experimental results of the two channels. While the effective power spectrum in the straight channel has only one maximum, that in the curved channel has two maxima on both sides of a wave number corresponding to the dissipation length. The spanwise correlation of radial velocity fluctuations in the curved channel takes a large negative maximum at a distance of about half the channel width. The streamwise integral length scales in the outer-wall side of the curved channel increase by about ten times those in the straight channel. These results indicate that intensive large-scale eddies which are unsteady but resemble Taylor-Gortler vortices exist in the curved channel. 続きを見る
33.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 高野, 剛 ; 早川, 智
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  57  pp.4064-4071,  1991-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5739
概要: Introducing a turbulent flow fully developed in a straight parallel-plate channel into a two-dimensional curved channel with a radius ratio of 0.92, measurements were made in the entrance section on the time-mean velocity, nonzero components of kinematic turbulent stress and other one-point multiple velocity correlations. No significant steady Taylor-Gortler vortices are found and the flow field is completely two-dimensional throughout the entire region of the entrance section. When arranged with wall variables, the time-mean velocity and turbulent stress distributions in the vicinity close to the walls are slightly affected by the wall curvature, while the skewness and flatness of the velocity fluctuation are strongly affected by it. Triple velocity correlations follow a complicated progress to arrive at fully developed states. The results obtained can be used as a data base to verify various types of turbulence models. 続きを見る
34.

論文(リポジトリ)

論文(リポジトリ)
反町, 和則 ; 長谷川, 富市
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  57  pp.3408-3413,  1991-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5738
概要: The driving torque of two-roll nipping polymer solutions, one rotating and the other fixed, was measured. Aqueous glycerin solution possessing Newtonian dynamic properties was used as the mother liquid, and polyethylene oxide (PEO) or polyacrylamide (SEPARAN) was mixed into it at the concentration level of 10 to 1000ppm 's in weight. It was found that the torque is mainly concerned with the viscosity for glycerin and diluted polymer solutions, but for non diluted polymer solutions it takes values greater than those estimated with the viscosity possessed by the solution. A line of vortex was observed at the nip entrance in the direction of the roll axis for non diluted solutions, but not for the diluted solutions. Torque and force were estimated using the second-order fluid model with an assumed simple flow field. The result shows that the torque is not affected by the elasticity of fluid, but the force is directly related to the second normal stress coefficient of the fluid. 続きを見る
35.

論文(リポジトリ)

論文(リポジトリ)
長谷川, 富市 ; 松川, 和正
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  57  pp.3013-3017,  1991-09.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5737
概要: A pressure gauge of the diaphragm type of high sensitivity has been developed to measure small differential pressures. Low and high pressures are each led to chambers which are separated with a membrane; the differential pressure between the two chambers give a displacement to the membrane, and the displacement is detected by a small laser displacement sensor through a glass window in the chamber wall. Tested membranes are permanently deformed in advance to a wavy form in order to give high sensitivity or are otherwise used in the flat condition. Easy exchange of the kinds of membranes makes it possible to widen the range of differential pressures measured. Calibration is made by means of a simple method using water heads. This type of pressure gauge can measure the pressure of magnitude from 0.1 Pa to 10 Pa. 続きを見る
36.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 近藤, 泰平
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  57  pp.1681-1688,  1991-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5735
概要: When a partial differential equation is solved numerically, it is usual to discretize the calculating domain into many elements by elaborate handwork. For this discretizing, we devised a new method with which the three-dimensional domain can be divided automatically into Voronoi polyhedron elements around arbitrary nuclear points. This method is described in detail giving an example. When Voronoi polyhedron elements are used, the various differential equations can be easily transformed into simultaneous algebraic equations for each of the nuclear points, for which parallel processing can be done more speedily and accurately. Moreover, the Voronoi polyhedron element table has possibilities of future growth; it can be used directly as an analytical method of solving a partial differential equation and it can be transformed into an ordinary tetrahedron element table. 続きを見る
37.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 中村, 寿 ; 近藤, 泰平
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  57  pp.1795-1801,  1991-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5736
概要: A method of discretizing a three-dimensional closed space into the Voronoi-polyhedron elements was applied to the numerical analysis of heat-conduction problems in heterogeneous solid mixtures. The computation was done for various mixtures of two randomly distributed components. Thermal conductivity of the two-component mixture is more strongly affected by the arrangement of components with respect to the mean heat flow direction than by the shape of components. The statistical mean of thermal conductivity can be roughly approximated by the geometrical average. Empirical formulae were obtained from the results. In order to accurately predict the thermal conductivity of a mixture of three or more components, the numerical calculating method divised in this study can be employed successfully. 続きを見る
38.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 関野, 龍男 ; 長谷川, 富市
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  57  pp.958-965,  1991-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5734
概要: Transmitting forces generated in a reverse squeezing film were measured and calculated when an upper spherical surface was caused to separate relative to a lower flat plate at a constant speed. The experimental results obtained were similar to those for normal squeezing flows, despite the opposite squeezing motion. Namely, no elastic effects were shown in the forces measured for PEO solutions. In the case of Separan solutions, however, the measured force overshoots the force estimated by consideration of viscous stress alone at the inception of reverse squeezing. In addition, the maximum rates of the overshoot were nearly equal to those obtained in normal squeezing under the same starting conditions expect for the direction of motion. A constitutive equation yielding the stress overshoot was used in the analysis of these flows under the condition where shear stress dominates. The analytical results approximately agree with the experimental ones for normal and reverse squeezing flows. 続きを見る
39.

論文(リポジトリ)

論文(リポジトリ)
長谷川, 富市 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  57  pp.464-469,  1991-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5733
概要: At first the elongational stress is derived to be ρυ^2, where ρ is the fluid density and υ is the local flow velocity. T hen macromolecular chains elongated in the solution are assumed to be thin rods and to associate with each other due to mutual interactions, and Batchelor's theory of suspension of thin rods is utilized to obtain the elongational stress for dilute polymer solutions in the elongational flow. Finally, the velocity distribution along the flow direction is derived over the upstream region of converging flow. The results obtained are confirmed to agree with the experimental ones. 続きを見る
40.

論文(リポジトリ)

論文(リポジトリ)
長谷川, 富市 ; 反町, 和則
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  56  pp.2908-2913,  1990-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5732
概要: This paper deals with the pressure generated btween two flat disks in the fluid, one lower disk fixed and another upper disk moved perpendicular to the fixed lower one. Results obtained from the experiment are as follows :When the upper disk approaches the lower one, viscoelasticity of the fluid decreases the pressure below the pressure of corresponding Newtonian fluids, whereas in the case of separating the upper disk from the lower one, the pressure takes minus values of about - 3.5 × 10^5Pa and the magnitude is increased by the viscoelasticity of the fluid used. This minus pressure is raised to a vacuum pressure by the cavitation inception inferred, the vacuum pressure holds constant for a duration and finally the pressure abruptly increases by the cavity extinction which accompanies pressure vibrations of high frequencies. These experimental results are qualitatively explained using the assumption of squeezing flow and the constitutive equation of the second order fluid. 続きを見る
41.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 関野, 龍男 ; 長谷川, 富市
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  56  pp.2551-2557,  1990-09.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5730
概要: Transmitting forces were measured during the time when a upper spherical surface was approaching to a lower flat plate at a constant speed and after the movement of the upper surface was stopped. The forces measured for glycerin and PEO solutions were predicted by the theory of viscous fluids. In the case of Separan solutions, however, overshoot of the force was seen at the inception of the squeezing motion and the maximum in magnitude was about 1.5 times larger than the force estimated with the viscous stress. This trend agrees well with those of the stress overshoot in simple shear flows. After the squeezing motion was stopped, the clearance between two surfaces was observed to slowly decrease because of the spring back of the load cell attached to the lower plate. At this stage, the larger transmitting force was maintained for the Separan solution than that for the viscous fluids. This result is considered to be related to the stress relaxation. 続きを見る
42.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 高橋, 武雄 ; 吉川, 実
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  56  pp.2576-2581,  1990-09.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5731
概要: The flow accompanied with turbulent Taylor vortices between inner-rotating and outer-stationary cylinders is analyticall y treated by using two kinds of κ-ε models. The results obtained with both models are generally in good agreement with the existing experimental results. No marked tendency for the secondary flow to disappear with increasing rotating speed is found within the range of the calculation. For a fixed value of Reynolds number, there exists a certain radius ratio which makes the intensity of the vortex maximum. The more this intensity decreases, the more the turbulence energy increases. As the radius ratio approaches unity, the intensity of the vortex decreases monotonously. Conversely, the intensity of the circumferential component of the secondary flow continues to increase until a radius ratio very close to unity. The hypothesis that the vortex determines its shape so that the total amount of the dissipation rate becomes maximum is substantially consistent with the experimental evidence. 続きを見る
43.

論文(リポジトリ)

論文(リポジトリ)
長谷川, 富市 ; 斎藤, 秀俊 ; 石塚, 一男 ; 中村, 仁志 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  56  pp.675-683,  1990-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5729
概要: Elasticities were measured under the conditions of shear and elongational flows of PEO and Separan solutions below the c oncentration level of several tens of ppm. The first normal stress difference in a shear flow was measured by utilizing reactions exerted by a jet issuing from a capillary, and the elongational stresses were also obtained separately with reactions or pressure drops produced in the flow through small orifices. The following points were clarified: the first normal stress difference τ_<11>-τ_<22> had a relationship of the power law type with the shear rate γ, that is, τ_<11>-τ_<22>∝γ. For the PEO 5 ppm solution, the power law index s was 2.0, as predicted with the Maxwell model, and in this case, the relaxation time was determined as 0.0016 second. For the other solutions used, we had 1.2< s < 2.0 and the measured first normal stress differences could be expressed with a modified Maxwell model. The elongational stresses measured with the two methods of jet reaction and pressure drop generally agree with each other. The elongational stress can be expressed, albeit approximately, with the Maxwell model or the modified Maxwell model depending on the concentration of the solution used. In some cases, the elongational stresses of PEO solutions, at least qualitatively, agree with predicted values of the yo-yo model proposed by Ryskin. 続きを見る
44.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 細川, 喜弘 ; 長谷川, 富市 ; 近野, 正昭
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  55  pp.3691-3696,  1989-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5728
概要: Experiments have been conducted with dilute water-Separan solutions on the reverse squeezing flow between a flat plate and a spherical surface of a large radius of curvature. The separating motion is started from a stationary and contacting state by applying constant forces. The separating rate in the polymer solutions is compared with that predicted by power law fluids. At the beginning of the motion, the separating rates in the Separan solutions are smaller than those in the inelastic liquids, as was shown in the 1st report for PEO solutions. These results cannot be explained by ordinary continuum mechanics because of the very small clearance between two surfaces ion the center region where the molecular size is close to the clearance size. When the separation is increased in magnitude, a considerable difference is shown between the results of Separan and PEO solutions despite similar viscoelastic properties in steady flows. Namely, the separating rates in the PEO solutions are close to those in the inelastic liquid, while smaller rates are maintained in the case of Separan solutions. It is considered that these results are due to the difference between the unsteady viscoelastic properties, stress overshoot, for example, of two different polymer solutions. 続きを見る
45.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 高野, 剛 ; 山田, 幸英
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  55  pp.2581-2589,  1989-09.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5727
概要: Mean flow properties, including turbulent stresses, were fully measured in a turbulent Taylor vortex flow between outer stationary and inner rotating cylinders with a radius ratio of 1/0.98. The static pressure distribution on the outer wall confirmed that many turbulent Taylor vortex pairs about twice as high as the channel width continued to exist over a wide range of Taylor numbers varying by more than one digit. A new technique using a grid was effectively applied to fix a vortex pair to be measured at the required position during the velocity field measurements. In the core region extending over 60% of the channel width, the secondary flow contributed to the angular momentum transfer by about 90% . The turbulent stress distributions were characterized by production and convection due to the secondary flow. 続きを見る
46.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 細川, 喜弘 ; 長谷川, 富市
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  55  pp.1039-1044,  1989-04.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5726
概要: The reverse squeezing low of dilute polymer solutions has been studied utilizing a flat plate and a spherical surface of a large radius of curvature. In this experiment, both surfaces are forced to separate by applying constant forces from a stationary and contacting state. All the liquids used are Newtonian in viscosity. The following points are found by comparing the results of inelastic liquids and viscoelastic liquid. In the case of the viscoelastic liquid, the surfaces separate from each other much more slowly than in the case of the inelastic liquid. This trend is clearly shown when the separation is small. The results predicted by the theory of inelastic fluids with the assumption of the quasi-steady state agree well with the experimental results. The same assumption, however, cannot explain the slow separation effect because of a small contribution of elastic terms. 続きを見る
47.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 高野, 剛 ; 内山, 則之 ; 窪田, 正博 ; 小林, 良充
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  54  pp.3354-3361,  1988-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5725
概要: Mean flow properties and one-point multiple velocity correlations including turbulent stresses have been measured in a two-dimensional turbulent flow through a curved channel with a radius ratio of 0.92. The results for the fully developed region are presented and compared with those of a parallel plate channel. The turbulence energy balance shows that the greatly enhanced turbulent diffusion away from the outer wall extends to about 2/3 of the cannel width, and reduces the equilibrium layer thickness considerably. It is found that an existing model for the pressure-strain correlation simulates with good accuracy the experimental values obtained from the turbulent stress balance. The triple correlation balance reveals that the terms relating to the mean flow are of the same order of magnitude as other terms even in the core region where turbulent diffusion plays an important role. 続きを見る
48.

論文(リポジトリ)

論文(リポジトリ)
福冨, 清 ; 長谷川, 富市
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  54  pp.1611-1615,  1988-07.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5724
概要: By assuming a uniformly converging radial flow on the upstream side of an orifice and integrating the equation of motion, an expression was derived to estimate elongational stresses for dilute polymer solutions at the orifice exit from pressure drops between the upstream and downstream of the orifice. The expression shown that the dilute polymer solutions usually give lower values of pressure drop than the solvent (water) does. An experiment was carried out to obtain the pressure drops for the orifice flow of water and dilute polyethylene exide (PEO)-water solutions. It was confirmed that the dilute PEO solutions yield lower pressure drops than water and the elongational stresses were estimated by the above-mentioned relation. The estimated elongational stresses broadly agreed with the ones previously obtained by a jet thrust method. 続きを見る
49.

論文(リポジトリ)

論文(リポジトリ)
長谷川, 富市 ; 塩原, 春樹 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  54  pp.119-124,  1988-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5723
概要: Sedimentation of small particles through liquid has been widely utilized to measure easily the size of the particles. Conserning this, experiments were carried out both for the case of a single particle falling through liquids and for the case where particles constitute a dispersion system and fall through liquids, and the following are clarified : (1) Drag coefficients measured on a single particle are approximately expressed with Stokes' law for creeping flow motion. (2) With sedimentation of dispersed particles, the falling velocity is in some cases abnormally low, though the concentration of the dispersion system used is hitherto thought to be too low to induce interaction among the suspended particles. (3) The abnomally low sedimentation speed is possibly due to the interaction among the suspended particles which are surrounded with electric double layers. (4) To suppress the occurrence of the abnomally low sedimentation speed and no measure the nearly correct size of particles, it is effective to add NaCl of the order of 1 mol/1 to the water of dispersion medium. 続きを見る
50.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 長谷川, 富市 ; 細川, 喜弘
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  53  pp.3504-3509,  1987-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5722
概要: This paper describes an experimental study on the flow of non-elastic and viscoelastic liquids in thin films held between a flat plate and a spherical surface which begins rolling movement. Properties of these liquids are Newtonian in viscosity. Empirical formulae have been derived for the maxima of liquid film thickness, cavitation points and thickening rates of liquid films. The viscoelastic liquids give about 1.5 times greater values than the non-elastic liquids with the non-dimensional thickness and thickening rate. The cavitation point is a function of the liquid film thickness and the formula is the same both for non-elastic liquids and for viscoelastic ones. 続きを見る
51.

論文(リポジトリ)

論文(リポジトリ)
長谷川, 富市 ; 福冨, 清 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  53  pp.3510-3515,  1987-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5721
概要: Excess pressure drops in a flow through small apertures are experimentally investigated for various kinds of liquid and the following three types are found according to the kind of liquid : non-dimensionalized excess pressure drops at Reynolds numbers of magnitudes about 10 have (1) nearly the same values as the theoretical ones of Stokes flow (liquid paraffin and butanol), (2) higher values than the theoretical ones of Stokes flow, but they are correlated with Reynolds numbers regardless of the dimension of orifices used (ethanol and carbon tetrachloride), and (3) higher values than the theoretical ones of Stoke flow, and they do not correlate with Reynolds numbers (water), increasing with increase in orifice diameter at the same Reynolds number. It is shown that the non-dimensionalized excess pressure drops of water have some correlation with a dimensionless number V(λ/ν)^<1/2>, where V is the mean velocity through an aperture, λ is the relaxation time of water and ν is the kinematic viscosity. 続きを見る
52.

論文(リポジトリ)

論文(リポジトリ)
福冨, 清 ; 長谷川, 富市 ; 中野, 裕二 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  53  pp.3516-3521,  1987-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/6303
概要: The velocity field of an inlet and outlet flow through small orifices was experimentally examined. The velocity along th e center line near the orifices was measured with a laser doppler anemometer, stream lines in the whole flow region were photographed, and the following points were clarified : (1) The center line velocities of liquid paraffin agree with the theoretical value of Stokes flow in the region of Reynolds numbers below 10. (2) With distilled water, a diverging angle of the issuing flow from a larger orifice is smaller than that of the issuing flow from a smaller orifice. Furthermore, a characteristic isolated vortex is generated on the downstream side of the orifice at the Reynolds number of from 10 to 30. (3) With ethanol used as a test liquid, the diverging angle of the issuing flow is small even for the Reynolds number of less than 10, and the flow resembles a jet. (4) The magnitude of the diverging angle of the issuing flow have a decisive effect on the value of the excess pressure drop at the same Reynolds number ; the larger the diverging angles is, the smaller the excess pressure drop is. (5) The dimension of the isolated vortex generated with the outlet flow of water is, when non-dimensionalized with the orifice diameter, correlated with a dimensionless number V(λ/ν)^<1/2>, where V is the mean orifice velocity, λ is a time proper to water and ν is the kinematic viscosity. 続きを見る
53.

論文(リポジトリ)

論文(リポジトリ)
長谷川, 富市 ; 福冨, 清 ; 鳴海, 敬倫
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  53  pp.2295-2302,  1987-08.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5719
概要: Elongational stresses of dilute polymer solutions have been assessed by utilizing the flow through small orifices under the condition of no vortex upstream of the orifice plane. The flow was approximated with a linearly converging flow toward an apex of a cone, its propriety being confirmed by the measured velocities, and the elongational stresses were determined from the measured thrusts of dilute polymer solutions. On the other hand, elongational stresses were theoretically obtained with the modified Maxwell model and the second order fluid. A comparison was made between the experimental and the theoretical results and the following points were clarified ; below the elongational rate 2×10^4(s^<-1>) the modified Maxwell model gives elongational stresses close to the experimentally determined ones, but above the elongational rate it deviates from the experimental results. the second order fluid is not sufficient to describe the stresses in this kind of elongational flow and an acceleration term such as δ^2e^<ij>/δt^2 may be necessary in this case. 続きを見る
54.

論文(リポジトリ)

論文(リポジトリ)
前川, 博 ; 小林, 睦夫 ; 矢代, 一男
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  53  pp.2560-2566,  1987-08.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5720
概要: A temperature-sensitive hot-wire under constant-temperature operation is analyzed to predict its frequency response to temperature fluctuations of the fluid. Effects of the finite Wollaston length, the over-heat ratio and the transconductance of the amplifier are taken into account, and a precise expression for the transfer function is derived. Various probes with different geometries are dynamically calibrated using the new developed procedure, in which a linear temperature distribution or a thermal wake just behind parallel line-sources is utilized to generate prescribed temperature fluctuations over a wider range of frequencies. Good agreement is obtained between the predictions and the experimental results on the gain of the sensitivity. The gain increases slightly as the over-heat ratio increases, and is least affected by the transconductance. Owing to the moderate thermal inertia of the Wollaston portion, the attenuation in the gain sometimes appears in the range of energy-containing eddies. 続きを見る
55.

論文(リポジトリ)

論文(リポジトリ)
鳴海, 敬倫 ; 長谷川, 富市
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  52  pp.1207-1214,  1986-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5718
概要: An experimental study has been made on the flow of viscoelastic inquids in thin films held between a flat plate and a spherical surface of a large radius of curvature, Especially, the case is investigated when a spherical surface begins to roll on a flat plate from a stationary and contacting state. Dilute polymer solutions are used as viscoelastic fluids, whose properties are elastic but Newtonian in viscosity. compared with non-elastic liquid, some effects are shown : The point of cavitation is far from the center of contact where the thickness of the liquid film is minimum. The thickness of the liquid film, generated with a rolling movement, is larger than that of non-elastic liquids. 続きを見る
56.

論文(リポジトリ)

論文(リポジトリ)
小林, 睦夫 ; 前川, 博 ; 高野, 剛 ; 平塚, 真二
出版情報: 日本機械学会論文集. B編 = 日本機械学会論文集. B編.  52  pp.298-304,  1986-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5717
概要: When a cylinder is placed perpendicular to a uniform flow of fluid, the upstream velocity vector can be determined from the velocities measured at two points in the region where the streamlines are deformed by the cylinder. Based upon this principle, a new type of probe, which possesses similar directional sensitivity to an X-probe and is suitable for anemometry in a narrow space, has been devised. Since the hot-wires are put outside the boundary layer on the cylinder, the optimal location for each wire can be examined by analysing the sensitivities for the probe operating in a plane inviscid flow. The probe, with a cylinder of about 0.1 mm in diameter, is calibrated statically and dynamically, and applied to measuring turbulent stresses and power spectra in simple flows. The experiment shows that this type of probe is reliable in various measurements of gaseous turbulence. 続きを見る
57.

論文(リポジトリ)

論文(リポジトリ)
外山, 茂浩 ; 横山, 誠 ; 愛田, 一雄
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.4415-4422,  1999-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5845
概要: In this paper, an observer design method is proposed for semiactive suspensions using VSS (Variable Structure System) theory, which provides a highly robust property against modeling errors and disturbances in the context of the matching conditions. The structure of the proposed observer is designed to be robust against the road variations which can be seen as nonstationary system disturbances. Although this structure basically requires to measure the actual damping force, it is estimated with a model of the damper. Therefore the influence of the estimation errors of the damping force on the state estimation is discussed in details, and the sufficient conditions for stability of the observer are given using Lyapunov theory. As a result, both the structure and design process of the proposed observer are simplified in comparison with existing ones. Numerical simulations illustrate not only the robust property of the proposed observer against the road variations but also a robust property against some unmatched modeling errors. 続きを見る
58.

論文(リポジトリ)

論文(リポジトリ)
川崎, 一正 ; 道脇, 宏和 ; 鈴木, 謙太郎 ; 田村, 久司
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.4476-4483,  1999-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5846
概要: The transmission errors of spiral bevel gears in Gleason system are analyzed in two cases. One is the analysis of hypothetical gears accurately cut according to Gleason's summary and the other is that of gears used actually. The tooth surfaces of the latter gears are measured by using a coordinate measuring machine, and the machine settings to generate the gears are estimated by the method of least squares so that the surface fits the measured data. The results of analysis showed that the tooth bearings obtained in both cases matched the desired ones, but the transmission errors differed from the desired, namely, they were not sufficiently small. In conclusion, although Gleason system pays attention to tooth bearing, it does not pay so with regard to the transmission errors. 続きを見る
59.

論文(リポジトリ)

論文(リポジトリ)
谷藤, 克也
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.4149-4155,  1999-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5844
概要: In the research work on dynamics of railway vehicles it is efficient in time and cost to employ scale models on a test stand. However, the similarity of creep forces between the wheel and the rail can not be satisfied in a scaled wheelset if it is made of steel, though steel is the material same as practical wheelsets. This paper deals with the effects due to the fault in the similarity of the creep force on the rolling behavior of scaled steel wheelsets. Then, referring to the idea developed by L. M. Sweet et al., a method is proposed for the experiments that utilize the scaled wheelsets. The method can keep the similarity on creep force by adding extra sprung load acting steady. The method is confirmed to be valid through the numerical simulation, but it requires the scaled wheelset to roll at the same speeds with the prototype and to be added large extra load. The apparatus that allow those demands has to be studied more before the method is realized in the practical experiment. 続きを見る
60.

論文(リポジトリ)

論文(リポジトリ)
羽田, 芳智 ; 川崎, 一正 ; 田村, 久司
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.2494-2501,  1999-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5843
概要: In a previous paper, a method for cutting hypoid pinion was proposed. In the method, instead of a basic member which is a hypothetical gear conjugate to ring gear, a newly introduced quasi basic member is used as the actual tool gear to generate the pinion. The quasi basic member is an approximate gear of the basic member. This paper introduces the method for setting up the quasi-basic member on the hypoid gear generator, namely, the method for calculating the machine settingS. The calculation starts with the designation of a central point of tooth bearing on the ring gear tooth surface. The pinion tooth surface which is generated by the quasi basic member becomes approximately a conjugate surface, so that the transmission error of this gear pair is very small. The proposed method does not need the so called tooth bearing development. When the experimentally made pinion was engaged with the ring gear given previously, the tooth bearing was desirable one. 続きを見る
61.

論文(リポジトリ)

論文(リポジトリ)
田村, 久司 ; 川崎, 一正 ; 羽田, 芳智
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.1642-1648,  1999-04.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5842
概要: It is necessary to modify the tooth surface of hypoid gears because of the need to deal with various kinds of errors. Skilled workers treat this problem using the trial-and-error method so far. In this paper, a theoretical method for cutting hypoid pinion under consideration of tooth surface modification is proposed. The method is based on the theory of basic member. The non-generating ring gear is cut by Gleason's Formate method. The pinion is generated by a newly introduced quasi-basic member whose tooth (tool) surface is a conventional conical surface. The quasi-basic member is a substitute tool gear for the basic member which is an imaginary gear generated by a ring gear. The tool surface of the quasi-basic member is in contact with the imaginary generated tooth surface of the basic member at a point, and envelops the imaginary surface in tool material side. There is a small clearance between the two surfaces. This clearance modifies the pinion tooth surface. The essence of this method is the setup of the quasi-basic member on the Gleason hypoid generator, namely, the determination of machine settings. 続きを見る
62.

論文(リポジトリ)

論文(リポジトリ)
岩部, 洋育 ; 水落, 真樹 ; 横山, 和宏
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.1719-1724,  1999-04.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1787
概要: It is very difficult to machine the side surface of a thin wall workpiece with precision using an end mill, because the deflection of the thin wall workpiece due to the cutting force is much larger than that of a thick wall workpiece. Then usual cutting conditions under low feed and small depth of cut are used in order to control machining accuracy. But it is impossible to avoid low productivity in this case. Therefore, in this study we propose a new cutting method, we call twin spindle type machining. With this method, we are able to machine the side surface of a thin wall workpiece with high accuracy, ensuring in the same time high productivity. The new cutting method needs two end mills of the same radius and helix angle, however, one of the mills should be right-edge and right -helix cutter while the other one should be left-edge and left-helix cutter. Under this method we may expect that the deflection of the thin wall workpiece due to the cutting force can be neglected because the same cutting force appears on the both sides of the wall surface. We produced a prototype equipment for twin spindle type machining and carried out some experiments. The effects of the new cutting method were confirmed by the results from cutting force and machining accuracy measurements. 続きを見る
63.

論文(リポジトリ)

論文(リポジトリ)
山田, 貴孝 ; 桜山, 岳史 ; 三村, 亘治 ; 舟橋, 康行
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.1062-1070,  1999-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5922
概要: This paper discusses stability of 3-D grasp considering rolling contact using potential energy approach. The synthesis of stable grasps is made by three-dimensional virtual spring which is fixed at the center of the fingertip. One spring is parallel to the normal and the others are parallel to the tangent plane at the contact. The kinematics of rolling contact equations (velocity and acceleration) between the object and finger are derived. Then, the stiffness matrix of the grasp is established. The derived stiffness matrix has six terms. The first three terms are due to stiffness of the three virtual springs respectively as well as remaining terms imply rotational stiffness which are influenced by curvatures, initial contact forces and contact position. The inverse problem, which is to determine the spring stiffness from the positive definiteness of stiffness matrix of the grasp system, can be also derived. Finally, some numerical examples are presented to illustrate the nature of the equations. 続きを見る
64.

論文(リポジトリ)

論文(リポジトリ)
大矢, 誠
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.1247-1254,  1999-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1773
概要: Thermally induced structural changes due to variations in the operating environment affect the measuring accuracy of three-dimensional coordinate measuring machine (CMM). The effects of temperature changes on the machine's structure and performance are very complex. It can often be difficult to find a complete relation between the change of error components of CMM and thermal effects because of the structural complexity of CMM. Various approaches have been taken by CMM manufacturers to cope with the problem of thermal error. One aim to compensate thermal effects is to guarantee the use of CMM not only in temperature controlled environments but also in workshop or workshop inspection area, where temperature variations are likely to be much greater. For the purpose of the compensation for thermal effects, it is necessary to have a clear grasp of the relation between changes of machine structure and temperature changes. In this paper the results of error component distribution measured in various thermal environments is shown and correction models to compensate the effects of temperature changes is proposed. The model assumes that the expansion/contraction of scales in each axis direction and the changes of squareness due to thermal changes are main causes of the changes in error components. Significant improvements in the accuracy of CMM can be achieved by the application of the proposed correction model. 続きを見る
65.

論文(リポジトリ)

論文(リポジトリ)
稲田, 明弘 ; 石原, 弘久 ; 桝田, 正美
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.766-772,  1999-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5841
概要: Friction force between magnetic disks and magnetic heads occasionally increases to cause a hard disk drive (HDD) to lock . In this paper, we discuss the friCtion mechanism at the interface between magnetic heads and magnetic disks, which are covered by the texture surface produced on a photo lithography Process. The texture surface is homogeneously dispersed with micro lands, 3 μm in diameter and 35 nm high, with a uniform pitch. Atomic force microscope (AFM) and Auger electron spectroscopy (AES) analyses make it clear that friction force increases abruptly at a land height below approximately 24 nm, and also the land height decreases not with growing wear of the top film in micro lands but with plastic subsidence of micro lands by fatigue during contact start stop (CSS) tests and continuous sliding tests. As a result, in order to reduce the subsidence of micro lands and improve the sliding durability of the disks, the second layer below carbon protection film is hardened to the same as that on the top film. 続きを見る
66.

論文(リポジトリ)

論文(リポジトリ)
劉, 宗先 ; 田村, 久司 ; 川崎, 一正 ; 三留, 謙一
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  65  pp.389-394,  1999-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5840
概要: A method for inspecting a pinion type cutter using a coordinate measuring machine (CMM) is proposed. In this method, the cutting edge profile of the cutter is indirectly measured as the intersecting curve between the flank of tool and the cutting face. Left and right side flanks of the cutter are considered to be the tooth surfaces of two different involute helical gears. The coordinates of a large number of points on the tooth surface and the face are measured with CMM. The tooth surface and the face are estimated from the measured data by the method of least squares. The cutting edge profile is calculated from the estimated tooth surface and the face. While the cutting edge profile is moved helically along a helinx of an imaginary gear which should be generated by the ideal cutter, it forms the tooth surface of the imaginary gear, and a pressure angle of this gear can be calculated. Pressure angle error of the pinion cutter is the imaginary gear's one. 続きを見る
67.

論文(リポジトリ)

論文(リポジトリ)
新田, 勇 ; 浅井, 広志 ; 小俣, 公夫 ; 紺野, 大介
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.4827-4834,  1998-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5839
概要: In a previous paper, we have developed a ultra precision method of joining an alumimum polygon mirror and a Sic self-acting air bearing using a shrink fitter. However, after the joining, the mirror surfaces need to be refinished by an ultra precision lathe to the fiattness of under 100nm, because the fiattness of the mirror surfaces will deteriorate beyond the allowable level. In this paper, we tryed to maintain the allowable fiattness of the mirror surfaces even after the joining by changing the shape of the polygon mirror. Optimum shapes were theoretically seeked by 2-dimensional FEM analysis through trial and error. After some 23 shapes were examind, we succeeded in finding the optimum shape that maintain the fiattness below 146 nm at a rotational speed of 30,000 rpm. The optimum shape obtained by the 2D-FEM analysis was examind by the 3D FEM analysis. 続きを見る
68.

論文(リポジトリ)

論文(リポジトリ)
道脇, 宏和 ; 川崎, 一正 ; 田村, 久司 ; 梅木, 武宏
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.4388-4394,  1998-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5838
概要: A method for estimating real machine settings in hypoid gear cutting is proposed. The coordinates of many points on the gear tooth surface are measured using a coordinate measuring machine, and a geometrical gear tooth surface which is strictly defined from the machine settings on a Gleason hypoid generator is estimated by the method of least squares so that the surface can fit the data of coordinate measurements. The real machine settings can be determined conversely from the estimated tooth surface. The measured hypoid gears are in practical use and the tooth bearing of the gears is acceptable. The path of contact is calculated using the estimated results and compared with the actual tooth bearing. The validity of the proposed method is confirmed by this comparison. The estimated real machine settings can be applied to the succeeding manufacturing, so that the trial-and-error process which is carried out by the skilled workers will fall into disuse. 続きを見る
69.

論文(リポジトリ)

論文(リポジトリ)
市野, 之彬 ; 川崎, 一正 ; 田村, 久司
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.4021-4027,  1998-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5837
概要: A method for inspecting the machine settings for straight bevel gear cutting is proposed. The bevel gear is generated by a newly introduced "quasi-complementary crown gear" instead of a conventional complementary crown gear. A tooth bearing of a pair of generated gears is theoretically desirable. The coordinates of many points on a tooth surface are measured at random using a coordinate measuring machine. The measured data should be including various type of information derived from the machine settings. Taking this fact into consideration, each information on the machine settings is extracted from the data using the method of least squares. The extracted items can be corrected, and they are: tool pressure angle, tooth angle, root cone angle, apex to back and tooth thickness. Using the proposed method, it is possible to produce interchangeable bevel gears. 続きを見る
70.

論文(リポジトリ)

論文(リポジトリ)
藤本, 裕 ; 谷藤, 克也 ; 宮本, 昌幸
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.1528-1533,  1998-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5835
概要: Comparison between responses of test train running on track irregularities artificially set on SHINKANSEN and those of vehicle dynamics simulation was made at the speed up to 210 km/h. In comparison between the measurements and simulation using basic parameters, the response to line irregularity of the measurements and simulation for the wave length longer than 40 m is nearly identical, although that of simulation becomes apparently larger than that of measurements for wave length of 20 m. Then the state of track irregularity artificially set was precisely investigated and an enlargement of gauge in the section of 20 m wave length was found. And simulation of the response assuming the gauge enlargement was nearly identical with that of measurements. In this report, the influence of wave length and gauge variation on the response to track irregularity mentioned above due to comparing measurements and simulation is analyzed. Besides, by using same simulation program, the influence of gauge variation on carbody hunting motion of new high speed SHINKANSEN train which has soft suspension between carbody and bogie due to bolsterless bogie is studied. 続きを見る
71.

論文(リポジトリ)

論文(リポジトリ)
山田, 貴孝 ; 三村, 宣治 ; 舟橋, 康行
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.1736-1742,  1998-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5836
概要: This paper addresses a new concept of constructing stable grasps of arbitrary planar object. We consider the manipulation of arbitrary objects by a multifingered hand, where the contact type is object rolls without finger slipping on the object surface. The synthesis of stable grasps is constructed by virtual springs at the frictional contact point. Each finger has a two directional virtual spring whose stiffness is known but compression is unknown. We explore the positive definiteness of the stiffness matrix of the grasp system from the view point of potential energy. It is shown that the stability is greatly influenced by spring stiffness, position and curvature of fingers, object curvature, and initial grasping forces. 続きを見る
72.

論文(リポジトリ)

論文(リポジトリ)
新田, 勇 ; 菅野, 明宏 ; 小俣, 公夫
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.1390-1397,  1998-04.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5834
概要: In a previous paper, a new simple and ultra-precision method of joining a polygon mirror onto a SiC self-acting air bearing has been developed by using a shrink fitter as a new machine element. In this new joining method, mirror surfaces were deformed beyond a desired flatness of 100 nm, because of contact pressure applied at inner surface of the polygon mirror. This distortion of the mirror surfaces is considerably affected by form errors or surface accuracy of the joining surfaces and sizes of the polygon mirror. Therefore a secondary cut after the joining is needed to finish the mirror surfaces to the desirable level. In order to dispense with the secondary cut, we must know how the form errors affect the deformation of the mirror surfaces. In this paper, we considered only an out-of-roundness as the form error. The effect of the out of-roundness on the deformation of the mirror surfaces was examined theoretically and experimentally. The calculated profiles of the mirror surfaces were in agreement with the experimented ones. In addition, the range of the out-of- roundness, in which the mirror surfaces were not deformed seriously, was shown in a 3-dimensional diagram. 続きを見る
73.

論文(リポジトリ)

論文(リポジトリ)
坂本, 秀一 ; 一宮, 亮一 ; 玉橋, 知之
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.986-991,  1998-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5833
概要: This paper deals with the development of a new method for detecting the number of cloth. It is necessary to detect one or plural number of sheets to avoid mishandling. This detecting sensor utilizes the variation of the phase of transfer function within entire acoustic system. The impedance of sheets varies with the number of sheets. Characteristic acoustic impedance and complex wave number define the material peculiar and the most fundamental characteristic. It is useful for the detection of the number of cloth to know characteristic impedance of cloth. So that, we tried to measure characteristic impedance and wave number. The measured impedance of sheets by transfer function method was introduced into theoretical analysis. The results of experiments and theoretical analysis show fairly good coincidence. 続きを見る
74.

論文(リポジトリ)

論文(リポジトリ)
山田, 貴孝 ; 毛利, 哲也 ; 三村, 宣治 ; 舟橋, 康行
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.584-589,  1998-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5832
概要: When the grasped object is in contact with external environment, it is necessary to perform the assembly tasks with identification of contact conditions. In the previous paper, we proposed an algorithm for the identification by using pure data. This paper treats the case when the data are contaminated with noise. We provide mutual relationships among criteria, and clarify properties of the criteria. We establish an algorithm for the identification. 続きを見る
75.

論文(リポジトリ)

論文(リポジトリ)
永井, 健一 ; 春日, 邦夫 ; 鎌田, 昌樹 ; 山口, 誉夫 ; 谷藤, 克也
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.23-28,  1998-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5915
概要: Experimental results are presented on chaotic oscillations of a reinforced beam subjected to lateral excitations. The beam is partially reinforced with boxed-type stringers. The beam is clamped at both ends on a base frame. One end of the beam is arranged to move to an axial displacement by attachment to an elastic spring. The beam is deformed to a post-buckled configuration by the axial constraint. Under the post-buckled condition of the beam, chaotic responses are generated in specified regions of exciting frequency. A response is expected from a system with a lower degree of freedom. The chaotic responses are analyzed by the Fourier spectrum, the Poincare section and the maximum Lyapunov exponent. It is found that the chaos of the beam is generated with the fundamental mode of vibration. Chaotic response includes the resonance modes both of a higher lateral vibration and of an axial vibration. The Poincare projections of the chaos show clearly the stretching-and-folding mechanism of the chaos attractor. The instability boundary of the chaos is obtained in the plane of exciting frequency and amplitudes of excitation. 続きを見る
76.

論文(リポジトリ)

論文(リポジトリ)
谷藤, 克也 ; 鈴木, 剛史 ; 斎間, 亨
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.110-117,  1998-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5830
概要: The speed-up on railway tends to require higher powered and heavier locomotives, thus two three-axle trucks or three two-axle ones are needed for the heavy locomotive to meet the limitation to axle load. Here, it is beneficial for heavy locomotives to employ forced steering trucks to reduce the lateral force between the wheel and rail during curve negotiation. This paper deals with numerical analysis about curving behaivor and running stability of the forced steering three-axle trucks. In the analysis, wheel lateral forces and the critical speed for stable running are examined parametrically varying leverage ratio and stiffness in the steering link, wheel tread conicity and wheelset supporting stiffness. In addition, the possibility for improving the critical speed is investigated. The results show that the proper value for the leverage ratio changes with curve radius, and that higher leverage ratio can make the running stability worse under large steering link stiffness. It is also shown that the proper tuning of the wheelset supporting stiffness increases the critical speed keeping the lower lateral force brought by the forced steering mechanism. 続きを見る
77.

論文(リポジトリ)

論文(リポジトリ)
谷藤, 克也 ; 小林, 哲也
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  64  pp.118-125,  1998-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5831
概要: In recent years, active suspensions have been studied for improving the ride quality of railway vehicles. In the active vibration control, it is important that the control system be robust against mass variation of the car body due to the varying number of passengers. However, it was indicated that LQG controller can become unstable when the body mass is lightened. Although H_∞ controller is stable against the mass variation, it is expected that the adoption of μ synthesis can improve the control performance still more. In this paper, the car body mass variation is considered in the linear state space representation of control object as parametric uncertainty, so that the μ synthesis can be adopted for the controller design. The control performance of the μ controller is investigated with a 3 d. o. f. half-vehicle model experimentally. As a result, it is shown that the μ controller improves the deterioration due to the car body mass reduction, and that it provides better control performance using a frequency dependent weighting function more than using constant weightings for the uncertainty of the mass variation. 続きを見る
78.

論文(リポジトリ)

論文(リポジトリ)
愛田, 一雄 ; 今井, 純一 ; 田村, 武夫 ; 長縄, 明大 ; 柿元, 真樹 ; 宇野, 壽郎
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.2739-2746,  1997-08.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5829
概要: Iron-frame box-columns are made by continuously welding steel plates. The inclination of the box-column must be kept constant under the deformation due to the thermal disturbance to maintain stable electric discharges. This is generally done by manipulating one of two oil hydraulic tandems which support the box-column. In this study, an automatic control method is proposed. An advantage of this control method is that it solves the problem of the detected variable differing from the controlled variable. All box-columns made using this automatic control method show satisfactory results both in external inspection and under ultrasonic inspection. 続きを見る
79.

論文(リポジトリ)

論文(リポジトリ)
岩部, 洋育 ; 竹本, 和博 ; 今井, 純一
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.2878-2885,  1997-08.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1793
概要: This paper deals with the accuracy of high-speed machining by an end mill on a circular and square workpiece and the error factors involved. The results are as follows. (1) In the steady region of cutting conditions, the profile error generation is related to the following: (a) the tool mark, (b) the cutting force, (c) the cutter radius, (d) the run-out of the cutter and (e) the droop. (2) However, in the transitional region, the following errors were generated at the periphery of the workpiece: (f) the notch-type error at the outset of the machining, (g) the overshoot error and (h) the gap-type and projection-type errors at the boundary point of the quadrant. (3) The error due to run-out of the cutter increased to the square of the angular velocity of the spindle in machining. (4) The error factors of the dimensional error of the workpiece machined to be circular are classified into (a), (b), (c), (d) and (e) listed above. Also, the predicted value calculated by adding all of the above error components effected on the dimensional error is almost coincidental to the experimental value. 続きを見る
80.

論文(リポジトリ)

論文(リポジトリ)
横山, 誠 ; 岩田, 義明 ; 片寄, 真二 ; 今村, 政道 ; 新部, 誠
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.2302-2307,  1997-07.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5828
概要: Current control algorithms for antilock braking system (ABS) are mostly table-driven and should be frequently modified through various experiments, because the braking dynamics are highly nonlinear with system uncertaintieS. In this paper, a new control algorithm is proposed for ABS using the theory of sliding mode control based on a linearized system model, which represents nonlinearities as external disturbances. The proposed sliding mode controller guarantees a highly robust performance against large variations in the system parameters and disturbances. Furthermore, a road surface estimation scheme using a disturbance observer is proposed in order to determine the optimal reference input. Simulation results reveal the advantages of the proposed method in comparison with conventional linear controllers. 続きを見る
81.

論文(リポジトリ)

論文(リポジトリ)
王, 英夫 ; 桝田, 正美 ; 西口, 隆 ; 秋山, 秀俊
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.2544-2551,  1997-07.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5827
概要: An experimental study of precision cutting of molding dies using single crystal diamond cutting tools for large Fresnel screens (size: T3×921×714 mm, Fresnel angle: 0.004-55.0), for improving the optical characteristics of the screens is described. The conclusions are as follows: (1) A burr is generated at the shoulder of the grooves during cutting, which causes compressed chip material to accumulate and laterally compress both sidewalls of the grooves; (2) The burr generation is suppressed by increase of the rake angle of the diamond cutters, decrease of the down feed rate, and reduction of stock removal; (3) Generation of a color corn on the Fresnel screen is caused by light escaping through non-lens surfaces; this is avoided by making the non-lens surfaces semi-transparent where the surface roughness is around 1μm R_<max> Through use of the above-mentioned information to improve the cutting process, desirable optical characteristics were achieved for Fresnel screens used in projection TVs. 続きを見る
82.

論文(リポジトリ)

論文(リポジトリ)
相田, 収平 ; 一宮, 亮一 ; 山田, 正直 ; 坂本, 秀一
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.1989-1995,  1997-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5157
83.

論文(リポジトリ)

論文(リポジトリ)
三村, 宣治 ; 舟橋, 康行 ; 毛利, 哲也
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.2061-2068,  1997-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5155
84.

論文(リポジトリ)

論文(リポジトリ)
高野, 剛 ; 原, 利昭
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.2076-2081,  1997-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5156
85.

論文(リポジトリ)

論文(リポジトリ)
高野, 剛 ; 山本, 仁 ; 原, 利昭
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.945-951,  1997-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5917
概要: In this work, a grip force dynamometer composed of pressure-sensitive conductive rubber was used to study the sensibility characteristics for grasping of a solid cylinder. The mechanical and physical parameters for ten normal male subjects (aged between 22 and 26) were measured at various cylinder diameters and weights. In addition, a direct linear transformation technique employing a video camera system was developed to determine the finger joint motion used to grasp the cylinder. The experimental results showed that the frictional coefficien of a palm is significantly dependent upon the deform ability of the soft tissue of the palm. It was found that the optimum cylinder diameter for easy grasping is nearly equal to the inner grip diameter formed by the fingers. 続きを見る
86.

論文(リポジトリ)

論文(リポジトリ)
大矢, 誠
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.402-408,  1997-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1780
概要: It is often necessary to utilize more than two probes in measuring three-dimensional (3-D) shapes by means of a 3-D coordinate measuring machine. Accuracy of measurement, especially of complicated shapes, can be improved by using multiple probes, because of the wide range of measured data. In the case that more than two probes are used, calibration of each probe must be performed to correct the zero position of the scale. In this paper, a new method for processing data measured by multiple probes is proposed. Two kinds of parameter related to shape and offset vector of a probe are involved in an observation equation. The parameters can be determined simultaneously by solving a set of observation equations for both standard probe and offset probe. The efficiency of the measurement by multiple probes is not affected because probe calibration and data correction are not essential in the proposed method. The simultaneous processing method is applied to experimental data. The most probable values and the standard deviations of the parameters are calculated by the least squares method. Results show that measurement accuracy of the method is almost the same as that of a conventional calibration method. 続きを見る
87.

論文(リポジトリ)

論文(リポジトリ)
田村, 久司 ; 劉, 宗先 ; 川崎, 一正
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.572-578,  1997-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5825
概要: A method for inspecting a helical gear using a coordinate measuring machine (CMM) is proposed. In the method, the coordinates of a large number of points on the tooth surface of the gear are measured at random using a CMM. The method is based on the idea that the pitch error, profile error, pressure angle error, and spiral angle error can be calculated from the measured coordinates because the information on various errors of the gear is included in the measured coordinates. For calculation of each error, the tooth surface is described as a function of each error item and then the values for the items are estimated from all of the measured coordinates by the method of least squares. The difference between the estimated value for the item and the corresponding design value is the error of the item. From the results of experiments, it is clarified that each error of a helical gear can be estimated using a widespread CMM instead of a specially designed measuring machine for gears. 続きを見る
88.

論文(リポジトリ)

論文(リポジトリ)
田村, 久司 ; 市野, 之彬 ; 川崎, 一正
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.579-584,  1997-02.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5826
概要: In the manufacture of straight bevel gears, there is usually a need for some "trial-and-error" process by which a good t ooth bearing is obtained. In this paper, a method for cutting straight bevel gears in which a trial-and-error process is not necessary is proposed. The method can be applied without the necessity of cutter modification or generator alteration. Each gear and pinion is generated by a newly introduced "quasi-complementary crown gear" instead of a conventional complementary crown gear. The quasi-complementary crown gear is a bevel gear whose pitch cone angle is 90° minus the root angle of the workpiece and whose tooth surface is a plane. The pitch cones of the quasi-complementary crown gear and workpiece roll with each other. Therefore, the ratio of roll between the crown gear and workpiece is expressed as a function of the root angle. The quasi- complementary crown gear produces a profile modification of the generated gear tooth. Gears made on an experimental basis showed a good tooth bearing as expected. 続きを見る
89.

論文(リポジトリ)

論文(リポジトリ)
岩部, 洋育 ; 島田, 智晴 ; 横山, 和宏
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  63  pp.239-246,  1997-01.  日本機械学会
本文リンク: http://hdl.handle.net/10191/1795
概要: It is very difficult to machine the side surface of a thin wall workpiece with precision using an end mill because the deflection of the thin wall workpiece due to the cutting force is larger than that of a thick wall workpiece. There are a number of unclarified points regarding to the machining accuracy of a thin wall workpiece, and an error avoidance method has not been established. Therefore, in this study we analyze deflection of the workpiece and tool using FEM and present basic data on how to realize precision end milling of a thin wall workpiece. The main results are as follows. (1) The loads acting at the nodal points of the FEM model workpiece and tool are calculated based on the cutting mechanism of a helical end mill. (2) The deflections of the workpiece and tool at the surface generating point on the cutting edge are calculated using the FEM under forces obtained in (1). The machining error of the side surface is obtained from the relative displacement of the workpiece and tool. (3) Calculated values of machining error almost coincide with the experimental values; thus, the appropriateness of the meshed elements, assumptions of cutting force distribution and the calculation method for the nodal load are verified. (4) The displacement ratios of the workpiece and tool to the calculated values of machining error are shown. Under experimental conditions, the former ratio exceeds 0.5 in the region of the thin wall workpiece with height exceeding 15 mm. 続きを見る
90.

論文(リポジトリ)

論文(リポジトリ)
川崎, 一正 ; 田村, 久司
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.4644-4650,  1996-12.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5824
概要: In this paper, a duplex spread-blade method for cutting hypoid gears with modified tooth surfaces is proposed. The duplex spread-blade method is a rapid and economical gear manufacturing method because both the ring gear and pinion are cut by a widely spread-blade cutter, that is, both sides of a tooth space are finished simultaneously by a cutter. In the proposed method, the nongenerated ring gear is cut by a cutter in which each cutting edge is altered from the usual straight line to a circular arc with a large radius of curvature and the pinion is generated by a cutter with straight cutting edges. The circular arc cutting edges enable application of the duplex spread-blade method theoretically and produce a tooth surface modification. The main procedure of this method is the determination of cutter specifications and machine settings which satisfy the duplex spread-blade conditions taking account of the position of tooth bearing. The validity of the proposed method was confirmed by the actual gear cutting. 続きを見る
91.

論文(リポジトリ)

論文(リポジトリ)
相田, 収平 ; 一宮, 亮一 ; 山田, 正直 ; 坂本, 秀一 ; 松村, 成生
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.4250-4256,  1996-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5914
概要: Recently, noncontact method for measuring cylinder configurations are required in industry. This paper reports the development of a new method for measuring cylinder configurations, using sound signal without contacting the contour surface. This method is based on the fact that the phases of sound waves scattered by a cylinder are delayed according to the diameter of the cylinder. Experiments were performed for various cylinder configurations formed by single and plural periodical deflection, using a loudspeaker, microphone and FFT-analyzer. It was found that the phase delays of sound waves were periodically changed according to the revolution of the cylinder, and the period between the phase delay and cylinder deflection was in good agreement. In addition, the angle of phase delay was linearly proportional to the magnitude of deflection. 続きを見る
92.

論文(リポジトリ)

論文(リポジトリ)
高野, 剛 ; 山本, 仁 ; 原, 利昭
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.4257-4263,  1996-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5913
概要: This paper is concerned with biomechanical analysis of the motion characteristics for grasping a solid cylinder. Contact pressure and surface electromyogram (surface EMG) of muscle flexor digitorum superficialis during grip motion were measured using a contact pressure measurement system with pressure-sensitive conductive rubber sensors and an electromyograph, respectively. In addition, direct linear transformation (DLT) technique with a video camera system is used to analyze three-dimensional joint motion of fingers. It was found that the tips of middle finger, ring finger and thumb are mainly used to stably grip the cylinder. The experimental results also showed that grip pressure increased with an increase in the weight of the cylinder with a constant diameter. 続きを見る
93.

論文(リポジトリ)

論文(リポジトリ)
川崎, 一正 ; 田村, 久司
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.4309-4314,  1996-11.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5823
概要: The measurement of transmission error is essential for development work and trouble-shooting in gearing when noise and vibration occur, and is also used for production control. For this reason, measurement and evaluation of the transmission error of hypoid gears are desirable. The authors have already proposed a method for cutting hypoid gears with modified tooth surface in which the transmission error is controllable to some degree. In this study, the static transmission error of the hypoid gears is measured under a lightly loaded condition. Two autocollimators which measure the exact angular positions of the ring gear and pinion are employed. The transmission error is obtained from the measured angular positions. As a result, the transmission errors caused by blade runout during pinion generation and by nonconjugation owing to the tooth surface modification were measured and confirmed clearly. The hypoid gears showed no deterioration of transmission error when misaligned. 続きを見る
94.

論文(リポジトリ)

論文(リポジトリ)
谷藤, 克也 ; 永江, 哲哉
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.3944-3950,  1996-10.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5822
概要: Recently, the application of active suspension has been studied for improving the ride quality of railway vehicles. In a ctive vibration control of railway vehicles, it is important that the control system be robust against parameter variations. In one such study, it was indicated that a LQG controller had low stability of the robustness to mass variation of the car body due to the varying number of passengers. In this paper, the H_∞ controllaw is adopted for a 3 d. o. f. half-vehicle model, and the improvement of control performance is investigated experimentally. As a result, it is shown that the addition of a bogie-related state variable to body-related ones provides better control performance. The control performance is improved further by shortening the sampling period. Moreover, it is also shown that the H_∞ controller is more robust against mass variation of the car body. 続きを見る
95.

論文(リポジトリ)

論文(リポジトリ)
新田, 勇 ; 古川, 英男 ; 小俣, 公夫 ; 紺野, 大介
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.2785-2791,  1996-07.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5821
概要: A conventionally shrink-fitted assembly of an aluminum polygon mirror and a SiC self-acting air bearing becomes loosened at temperatures as low as 60℃ because of the great difference in the thermal expansions of these two components, although it exhibits sufficient strength at room temperature. Temperature rise and centrifugal force in operation deform the mirror end surfaces by the order of hundreds of nano Meters or more. The distorted mirror end surfaces adversely affect the quality of devices such as photocopiers and laser printers. This problem has been solved by using a shrink fitter, which is a new machine element developed in previous work. The shrink fitter is ring-shaped and has several slits in the radial direction. Its material needs to have a higher coefficient of thermal expansion than aluminum. Thus, polyimide was used for the material of the shrink fitter. Dynamic properties, such as jitter and tracking accuracy, of the assembly fabricated using the shrink fitter were one-fifth to one-tenth of those of the conventional assembly. This new joining method eliminates the need for maintenance. The shrink fitter made it easier to attach the polygon mirror to the air bearing. The omission of final cutting of the polygon mirror after fabrication was discussed. 続きを見る
96.

論文(リポジトリ)

論文(リポジトリ)
谷藤, 克也 ; 西澤, 貴紀
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.2125-2131,  1996-06.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5820
概要: The FFLM vehicle system, in which a flip-flop linear motor with permanent magnets is used for propulsion, has been investigated. In this system, trucks are to be coupled as in a train and the basic function of a conventional railway wheelset is separated into 3 functions of support, guidance and propulsion. The running wheel, which is an independently rotating one, functions for support, the guide wheel for guidance and the FFLM for propulsion. Up to now, there have been no conventional railway vehicles employing coupled trucks. Thus, the effects of couplig trucks on train vibration have not becn examined. This paper concerns numerical analysis of the effects of coupling trucks on the lateral vehicle vibration, which is induced by lateral irregularities of the guide rail. The main results obtained are as follows. The lateral stiffness of the coupling at a position lower than the truck's center of gravity can reduce the lateral vehicle accelerations and the guide-spring distortion. The longitudinal stiffness between trucks has almost no influence on the lateral vibrations. The coupling of trucks has little influence on the vibration excited by cross-level irregularities of the running rail. 続きを見る
97.

論文(リポジトリ)

論文(リポジトリ)
三村, 宣治
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.1866-1871,  1996-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5818
概要: A 6-degrees-of-freedom (DOF) motion system using a new paralled link mechanism is developed for the purpose of evaluating human motion sensation. This motion system is made up of three five-bar link mechanisms, each of which has 2-DOF and is driven by AC servo motors. Therefore, this system is very small, but its working area is larger and its response is better than those of the hydraulic Stewart platform. Furthermore, I have developed a high-speed parallel signal processing controller for motion control and a new 6-DOF acceleration sensing system based on the parallel sensing concept. Combining the new motion and sensory system with a multi-video system, we have constructed a new analytical system for evaluating a wide bandwidth of motion sensation in riding such vehicles such as automobile or airplanes. 続きを見る
98.

論文(リポジトリ)

論文(リポジトリ)
田村, 久司 ; 川崎, 一正 ; 白石, 英亮 ; 田中, 正則
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.2005-2011,  1996-05.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5819
概要: The rotors of a screw compressor engage peculiarly with each other in comparison with helical gears. In order to obtain a compressor with high performance, it is necessary to clarify the peculiarity of the rotor tooth profile following the peculiar engagement. In this study, the peculiarity is investigated. The results of the investigation are as follows. (1) The trailing tooth profile of the rotor is fundamentally fixed. (2) The leading tooth profile of the rotor can be determined arbitrarily. (3) The volume of the rotor tooth space is fixed almost independently of the rotor tooth profile. (4) A blow hole occurs in the trailing tooth profile which is not a roulette. It is impossible to avoid a blow hole in the practical tooth profile. (5) If gas torque promotes the progressive rotation of the female rotor, the female rotor tooth thickness must be altered thin. 続きを見る
99.

論文(リポジトリ)

論文(リポジトリ)
谷藤, 克也 ; 島宗, 亮平
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.886-893,  1996-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5816
概要: Active suspensions have been studied to improve the ride quality of railway vehicles. In many cases, pneumatic actuators were employed in those studies. This paper deals with the application of oil-hydraulic actuators, which are expected to have stronger control effect on the running vibration. This is examined experimentally by using an actual-size vehicle model on a test stand. The LQG control law, in which state variables are estimated from measurable accelerations on actual railway vehicles, is adopted. The LQ control law, in which state variables are measured accelerations and their integrated quantities, is also adopted. The results show that both controllers have good vibration isolation performance in both harmonic and random excitations. The control force and the stability are improved by decreasing the lateral damping in parallel with the actuator in the secondary suspension. In this case, it is confirmed that the relative displacement between the car body and bogie does not increase. 続きを見る
100.

論文(リポジトリ)

論文(リポジトリ)
島崎, 義之 ; 一宮, 亮一 ; 坂本, 秀一 ; 田中, 誠三
出版情報: 日本機械学会論文集. C編 = 日本機械学会論文集. C編.  62  pp.949-954,  1996-03.  日本機械学会
本文リンク: http://hdl.handle.net/10191/5817
概要: The most popular fuel level measuring method presently in use employs a float and a resistor plate. This float follws the fluctuations of the fuel surface in an automobile fuel tank. A new accurate measurement of the variation of the cavity volume in the fuel tank has been investigated. This sensor is composed of a speaker, microphone and three Helmholtz resonators. This method detects the level and slant angle of the fuel surface. The sound frequency obtained experimentally is compared with the calculation result of the frequency found by the theoretical analysis in which the cavity system is connected with three Helmholtz resonators. This method of measuring the volume is applicable to measuring the fluctuating fuel surface in an automobile 続きを見る