ON THE MODERNIZATION OF THE BRAKE SYSTEM OF FREIGHT CARS

Abstract

The intensification of works to improve the running parts of freight cars in recent years is associated with significant deficiencies in the design of bogies. Extensive research is conducted, entirely new designs are created, existing systems are upgraded, and performance tests are conducted in the Russian Federation, the United States, China, the Ukraine and other countries. Components and spare parts, affecting driving performance of cars, are mainly exposed to changes and much less attention is paid to a brake system of bogies, which is very important in terms of train safety. In some innovative types of bogies attempts are made to improve the brake system with a variety of additional devices. However, during field tests this modernization shows often unsatisfactory results and its implementation is rejected due to lack of efficiency and reliability. The main problem is the inability to achieve complete return motion of the brake shoes from wheels during brake release. Three-piece bogie brake system, which is currently in use (including for innovative options) was developed in the 30s of the last century [4] so that the amendment of the design changes entails a violation of dimensional chains, to which the main parameters of brakes performance are related. Because of this, researchers and designers are still unable to find an effective solution for increasing the reliability of brake systems of bogies.

The objective of the authors is to investigate some theoretical and practical issues of modernization of brake systems of freight cars, using mathematical and engineering methods.

The article results in a theoretical justification of negative properties associated with uneven returnmotion of brake shoes from wheels in the brake system of three-piece bogies. Besides kinematic analysis reveals the conditions under which innovative solutions are possible. The guarantee of high efficiency of theoretically grounded modernization of the brake system of bogies is that by changing the nature of gravitational forces the latter do not incline the brake shoes to mounting in wheels, and developed design of the guide device provides a strictly uniform keeping of brake shoes relative to the forming wheel tread. Improved reliability is achieved by simplicity of design and the neutralization of destructive force moment.