Investigation of the friction and deformation behaviour of high-speed brakes

Abstract

Spring-applied brakes are widely used components in industrial drive systems. They provide a braking torque by friction between a mostly organic friction lining and a metallic counter surface. Increasing with decreasing size, they currently achieve speeds of up to 6,000 rpm, which corresponds to a sliding speed in frictional contact of up to 35 m/s. At the same time, there is a trend towards high-speed drives, with speeds of 10,000 rpm and above. So far, little is known about the behaviour of the friction value and torque of conventional spring-applied brakes with low-cost organic friction linings under these operating conditions. For this reason, a test rig was develop - ed that allows testing at sliding speeds of up to 120 m/s with different load inertias. The tests carried out at KAt so far showed that with limited friction work, the conventional spring-applied brake reaches the nominal braking torque at higher sliding speeds. In addition to thermal overload of the friction lining, plastic deformation of the friction bodies can also permanently disrupt the operating behaviour of brakes operated at high sliding speeds. The plastic deformation of the friction discs manifests itself, for example, in a saucer-like shape of the discafs, leading to a reduction in the air gap and causing unwanted changes in the friction conditions. This paper describes the relationship between friction work and friction coefficient in organic linings and the physical mechanism of the deformation process of the friction discs. Based on these possible measures to reduce deformation are explained.