Investigation on Hysteresis Losses into Disc Brake Gear for Heavy Vehicles

ABSTRACT The paper describes a new disc brake design procedure including the ADAMS model of the air-operated brake disc mechanism and its validation against the conventional hardware. A mechanical system simulation is used in the paper to forecast the full dynamic behavior of the complex brake unit system having a lot of cooperating with each other parts. INTRODUCTION The current tendencies in automotive industry need intensive investigation on problems of interaction between active safety systems and brake equipments. The special place is occupied here with creation of a new brake gear design which should possess, except for reliability and durability, such important for active safety systems properties as minimal hysteresis losses and the high response time. Nowadays brake control systems for heavy vehicles can be basically classified into two types: combined Air-Over-Hydraulic system, where the brake unit is hydraulically controlled, and Full-Air system, in which the brake unit is pneumatically controlled. Brake control system types are indicated in the Table 1. Table 1 Brake control system types Control Caliper support method Caliper slide method Fixed type Not related Pin slide type Hydraulic Floating type Rail slide type Pin slide type Pneumatic Floating type Rail slide type The influence of the brake gear on active safety systems is mainly determined through the hysteresis loop width. This parameter limits the possible frequency of cyclic braking during ABS operation. Until recently it was considered, that the disc brake design is practically optimal from the point of view of hysteresis losses. However, this statement is fair, only if to compare a design of drum and disc brake mechanisms. Really, the hysteresis losses value in a disc brake is approximately two times less than losses in a drum brake. But it can still reach 20%. An analytical dependence, which would allow defining a hysteresis value, is not received till now. In this connection manufacturers use empirical dependences or experimental characteristics at dynamic calculation of a brake gear. The presented paper makes an attempt to solve the problem under discussion using common analytical methods and simulation.