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論文(リポジトリ) |
論文(リポジトリ)
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谷藤, 克也 ; 森山, 淳
概要:
An axle supporting system which satisfy both steering and stability was proposed previously by one of the authors. To utilize the benefit of the proposed system fully, it is needed to decide the suitable parameter values under theoretical
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ground. This paper describes a parameter design method for the axle supporting system step by step, considering the maximum operation speed, the maximum curve radius, and so on. Here, the parameter values are restricted to be within the possible range for present railway vehicles. To show the effect of the parametrized axle supporting system, numerical simulation is performed for two cases, one is for high-speed inter-city train and the other is for low-speed mass transit one. Calculation results show that the curving performance, such as attack angle, lateral force and wear index, is improved with the parametrized system, maintaining the adequate stability, in both examined cases.
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| 2.
論文(リポジトリ) |
論文(リポジトリ)
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谷藤, 克也 ; 佐藤, 司
概要:
In order to reduce the lateral force between wheel and rail during curve negotiation of rail vehicle, some kinds of bogie truck with actively steered wheelsets have been investigated. This paper deals with a basic study about the
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actively steered truck, which employs a control law based on the self-steering ability of wheelset, measuring the relative yaw angle between the wheelset and the bogie frame. However, this control law helps not only the steering performance, but also the occurrence of running instability. Therefore, two methods are proposed to improve the stability. One is the method that adds the wheelset lateral velocity as the feedback state, and the latter is the one that gives some time lag to the control moment. Both methods are proved to be affective for the stabilization. Here, the latter is more practical because it does not need further measurement. Then, it is also confirmed that the control lag of the latter method does not deteriorate the steering performance under the practical curving condition with track irregularities considering the dynamic characteristics of electro-mechanical actuator.
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| 3.
論文(リポジトリ) |
論文(リポジトリ)
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谷藤, 克也 ; 道辻, 洋平
概要:
In the design of railway truck, the axle supporting rigidity is one of the important matters for good running performance. Up to now, the axle supporting rigidity has been selected in the trade-off between running stability and
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curving performance. This paper deals with a design method for the axle supporting mechnism, which can manage both to secure the running stability and to improve the curving performance. This method utilizes the Bode diagram and makes it possible to evaluate the running performance in the frequency domain. The analytical model of a railway truck is represented as a feedback control system, in which the longitudinal rigidity of the axle supporting mechanism is regarded as the compensator gain. The gain corresponds to the supporting rigidity and it becomes high in the higher frequencies and low in the lower frequencies. An example of the axle supporting mechanism with such frequency characteristics is composed of three elements such as main spring, auxiliary spring and damper. The auxiliary spring and the damper are set in series and placed parallel to the main spring. The effects of the mechanism are shown in the numerical simulation considering track irregularity and the method is confirmed to be available to design the truck with steering ability.
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| 4.
論文(リポジトリ) |
論文(リポジトリ)
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谷藤, 克也 ; 鈴木, 剛史 ; 斎間, 亨
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
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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.
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| 5.
論文(リポジトリ) |
論文(リポジトリ)
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谷藤, 克也 ; 松嶋, 亨 ; 斎間, 亨
概要:
For a heavy haul railway vehicle negotiating tight curves in a factory yard, it is beneficial to employ forced steering trucks to reduce the lateral force between the wheel and rail. The forced steering truck has a wheelset supporting
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mechanism composed of hanging links and compressing ones for easy steering. The truck should also have a short wheelbase to meet special requirements in the yard. This paper deals with numerical analysis of dynamic behavior of the forced steering truck, in which running stability and the lateral force are examined, considering the wheelbase, the running speed, the longitudinal stiffness caused by the link mechanism, steering link stiffness and the leverage ratio. Results show that it is disadvantageous for both the running stability and the curving behavior to use a short wheelbase, and that the decrease of the steering link stiffness and the increase of the running speed also have disadvantageous effects on the curving performance. It is important for trade-off between the running stability and the curving behavior to select proper values for the longitudinal stiffness of the link mechanism and the leverage ratio.
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| 6.
論文(リポジトリ) |
論文(リポジトリ)
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谷藤, 克也 ; 渡辺, 晋輔
概要:
Trucks with independently rotating wheels are applicable for speedup on railways. However, the truck has no steering function in itself, so that it needs some additional guiding mechanism for steering. This paper deals with
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fundamental analyses of the vibration characteristics of such a truck with independently rotating wheels, which has guide-wheels to provide the steering function. Running stability and forced vibration excited by guide-rail irregularities are examined numerically. Effects of guiding forms, such as a front & rear side guide and a front side one, and of guide-spring stiffness on the kinematic characteristics are clarified, and an allowable stiffness range of the guide spring is specified for the expected operation speed of 400km/h.
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