Degradation properties of cone-type axle spring rubber for railway vehicles

To economize on the manpower needed for train maintenance, evaluation of th e degradation properties of the cone-type axle spring rubber is strongly de manded. It is a very important material to control train vibration, and whe ther it can be used for a long period of time must be examined. As a result of experiments on degradation properties of the axle spring rubber, the fo llowing properties have been revealed. As the initial stage of its usage, t he inner layer of axle spring rubber is degraded more in molecular chains t han in the middle and outer layers because the vibration load is applied di rectly to the soft inner layer. As the inner layer is degraded, however, it loses the ability to absorb vibration, and the vibration load is transferr ed to the middle layer. Consequently, the degradation is the greatest in th e middle layer of the three layers after it is used for several years. More over, the degradation of the axle spring rubber can mainly be attributed to complex factors, such as environmental conditions, heat generated when the rubber absorbs vibration energy and fatigue due to vibrating stress.