Page 358 - Automotive Engineering Powertrain Chassis System and Vehicle Body

12.1
Chapter 12.1

Braking systems

Julian Happian-Smith

The aim of this chapter is to: The chapter commences with a review of the function
of a brake system together with an outline of the prin-
Aid the designer to understand the legal require- cipal components and their possible configurations. The
ments of braking systems;
subject of legislation is reviewed and its importance as
Understand the basic requirements for braking a tool to aid the designer of a brake system is highlighted.
systems to be successful;
Straight forward kinematic and kinetic analyses are used
Understand the design process for achieving to address the fundamentals of the braking problem as
an efficient braking system; a precursor to the analysis of brake proportioning, ad-
Appreciate the material requirements for efficient hesion utilization and other related issues. A case study is
braking systems; built into this section of the chapter that illustrates the
Understand current developments in braking control application of the theory and so reinforces un-
systems. derstanding. The selection of appropriate materials from
which to manufacture the friction pair is reviewed
and problems linked to thermo-mechanical behaviour
12.1.1 Introduction
highlighted. The chapter concludes with a brief summary
of more advanced topics, often linked to modern chassis
The safe and reliable use of a road vehicle necessitates the control, that integrate the braking system with other
continual adjustment of its speed and distance in response chassis systems.
to change in traffic conditions. This requirement is met in
part by the braking system, the design of which plays a key
role in ensuring a particular vehicle is suitable for a given 12.1.1.1 The functions and conditions
application. This is achieved through the design of of use of a brake system
a system that makes as efficient use as possible of the finite
amount of traction available between the tyre and the road In order to understand the behaviour of a braking system
over the entire range of operating conditions that are likely it is useful to define three separate functions that must be
to be encountered by the vehicle during normal operation. fulfilled at all times:
The purpose of this chapter is to introduce the reader
(a) The braking system must decelerate a vehicle
to the basic mechanics associated with the deceleration
in a controlled and repeatable fashion and when
behaviour of a road vehicle and provide insight to the
appropriate cause the vehicle to stop.
many issues that must be addressed when selecting the
(b) The braking system should permit the vehicle
brake rotor and friction materials. A complete coverage is
not feasible within the confines of a single chapter and so to maintain a constant speed when travelling
a set of references and additional reading is provided at downhill.
its end that points the interested reader to further (c) The braking system must hold the vehicle stationary
sources of information. when on a flat or on a gradient.

Introduction to Modern Vehicle Design; ISBN: 9780750650441
Copyright Ó 2001 Julian Happian-Smith. All rights of reproduction, in any form, reserved.