2. Silicon buffer for freight vehicles

A silicon buffer was developed to improve the quality of freight transport by reducing movement at the front and back of wagons.
Yard tests demonstrated the effectiveness of the device in reducing acceleration at the front and back of wagons and that its basic functions were working properly.
Applicability and effectiveness of the device on long freight trains was verified through simulation.

A silicon buffer for use on freight vehicles was developed with a view to reducing the relatively frequent shocks at the front and back of vehicles due to play on coupling equipment (Fig.1). The device comprises a combination of two shock absorbing rubbers each possessing extension and compression cycles, which mutually offset any preload force, maintaining soft characteristics with no initial pressure. In order to adapt a system which is already commonly used on passenger vehicles to freight vehicles, a cylinder filled with high viscosity silicon rubber was inserted inside the shock absorbing rubber (Fig.2).

The structure of the device is designed to ensure a proper shock absorbing function, whereby the deformation resistance of the rubber is complemented by the flow resistance of the silicon rubber in response to the size of the shock.

Tests on 6 container wagons showed that the front and back acceleration wave forms of the wagons equipped with the device were markedly different to those with no device. Comparison of displacement - coupling force on the same coupling equipped with the newly developed device and the traditional type demonstrated that the new device was more elastic (Fig.3).

Simulated endurance tests with very large loads exceeding 1.000t demonstrated that the device could be adapted for practical use.

Fig.1 Picture of the outside of the newly developed device
Fig.2 Structure of device (left: assembly; right: shock absorber unit)
Fig.3 Effect on lowering acceleration at front and back of wagon
(driving force 4 notches ON⇔OFF approximately every 3 seconds)