Thermal and tribological characteristics of a disc-type magnetorheological brake operated by the shear mode

Abstract

In this article, thermal characteristics and tribological properties of a disk-type magnetorheological fluid–based brake are investigated under various brake operating conditions such as different working gaps. In order to achieve this goal, a theoretical analysis of the heating and heat dissipation of the magnetorheological brake is first performed and then the transient temperature behaviors of the magnetorheological brake are investigated through simulation works associated with the finite element method. Subsequently, an experimental apparatus is established to measure temperature distributions of the magnetorheological brake as a function of the operating time. Thereafter, several heating and wear tests are conducted on the magnetorheological brake, and worn surfaces of the friction plates are observed using a scanning electron microscope to understand tribological characteristics of the magnetorheological brake. It is shown that the smaller working gap causes the higher temperature compared with the larger gap under the same magnitude of the input current applied to the magnetorheological fluid domain. This thermal behavior consequently results in the reduction of the braking torque. It is also demonstrated from the wear test that the small working gap significantly affects both wear and tribological characteristics showing the large ridges and deep grooves on the worn surfaces of the friction plate.