Development of longitudinal vibration isolator between carbody and bogie for railway vehicle (Study on characteristics of the device by multi-body dynamics model)

Abstract

Carbody elastic vibration of a railway vehicle negatively affects the ride comfort of passengers. One of the sources of the vibration is excitation force induced by the longitudinal vibration of the bogies. The excitation force transmits to the carbody through longitudinal coupling devices between the bogie and the carbody, such as traction links and yaw dampers. Since the longitudinal coupling devices can affect running stability of the vehicle, it is necessary to develop a device which copes with both vibration reduction and running stability. The purpose of this study is to develop a device which achieves both vibration reduction and the running stability. To confirm the vibration isolation performance and also to evaluate the running stability, using multi-body dynamics software, we construct a simulation model of a test vehicle equipped with traction links and yaw dampers with rubber bushes. The simulation reveals that the elastic vibration can be reduced by the traction links equipped with soften rubber bushes. On the other hand, running stability decreases under the condition that the rubber bush of the traction link is soft, especially under the condition when another damper fails. In the simulation, we investigate the desirable displacement-load characteristics of a rubber bush for the traction link in order to reduce the carbody elastic vibration and to secure the running stability. As a result, we confirm that it is possible to cope with both vibration reduction and the running stability by configuring parameters on displacement-load characteristics of rubber bush so that the rubber bushes vibrate in small stiffness at micro amplitude and in large stiffness at large amplitude. Furthermore, we propose a design method of the vibration isolator considering running resistance, and confirm the effectiveness of the method on both vibration reduction and security of the running stability.

Keywords

• railway vehicle
• multi-body dynamics
• elastic vibration
• hunting
• running resistance