Influence of the coefficient of mutual overlap on the wear rate of disc brake pads
Objective: To study the influence of the coefficient of mutual overlap on the integral linear and mass intensity of wear of the railway disc brake pad operating in tandem with a 35 SG steel disc, under real load-speed conditions reproduced on a full-scale test bench. Methods: The experiment preparation and conduct methods, as well as statistical processing and graphic display of results have been used. The experiments have been carried out on a full-scale test bench that reproduces the force interaction of the disc brake working elements according to the mass-dimensional and load-speed criteria. An innovative feature of the test bench is the capability allowing to adjust the disc brake coefficient of mutual overlap within a wide range of values. Results: The dependences of linear and mass integral intensities of wear of the railway disc brake pad on the coefficient of mutual overlap are given. It has been established that the linear integral wear rate tends to decrease with the increase of this coefficient, and the integral mass wear rate remains approximately equal for reproducible coefficients of mutual overlap. When the coefficient of mutual overlap is close to unity, the intensity of wear is minimal. Practical importance: It was found that the coefficient of mutual overlap is one of the main factors affecting the life of disc brake pads in operation, which is advisable to take into account when developing advanced disc brake designs. It is concluded that a promising friction brakes design would be the one providing for the coefficient of mutual overlap with a value close to unity, which would reduce the wear rate of disc brake pads and, accordingly, increase their service life.