Graduation Design (Thesis) of Wuhan University of Technology

Design of Brake System for Micro-electric Vehicle

School: International Education College

Class: Automotive Engineering Class 1303

Name: Yang Yuan

Adviser： Yu Houyu

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Contents

Abstract

Chapter 1 Introduction 1

1.1 Purpose and significance 1

1.2 Overview 1

1.3 Requirement 1

Chapter 2 Selections of Main Parts of Brake System 3

2.1 Select front and rear wheel brake types 3

2.2 Select type of drum brake 4

2.3 Select type of disc brake 5

2.4 Select type of drive form 6

2.5 Select shunt system 6

2.6 Select brake force adjusting mechanism 7

Chapter 3 Select main parameter of brake system 8

3.1 Braking force and distribution coefficient of braking force 8

3.2 Synchronous adhesion coefficient 12

3.3 Braking strength and adhesion coefficient utilization 14

3.4 Maximum braking torque of brakes 15

3.5 Factor of the brake 16

Chapter 4 Main Determination of Brake 17

4.1 Main determination of disc brake 17

4.1.1 Diameter of brake disc 17

4.1.2Thickness of brake disc 17

4.1.3 Inner radius and outer radius of brake pad 17

4.1.4 Working area of brake pad A 17

4.2 Determination of Main Parameters of Drum Brake 18

4.2.1 Diameter of brake drum 18

4.2.2 Wrap angle of brake shoe friction plate and width b 18

4.2.3 Distance from center of brake to action line of stretch force P 19

4.2.4 Coordinate position of brake shoe hoist center and 19

4.2.5 Origin angle of friction pad 19

4.2.6 Friction coefficient of brake pad f 19

Chapter 5 Calculation of brakes 21

5.1 Brake torque on brake shoe of drum brake 21

5.2 Check heat capacity and temperature rise of drum brakes 23

5.3 Calculation of hydraulic brake drive mechanism 24

5.4 Calculation of brake torque of disc brake 26

5.5 Check heat capacity and temperature rise of disc brake 27

5.6 Calculation of braking distance 28

5.7 Calculation of parking brake 29

Conclusion 31

References 32

Appendix 33

Acknowledgment 34

Abstract

The vehicle brake system is the mechanism that make the car slow down or stop and keep the speed of the car downhill as well as keep the car parked in place.

With the rapid development of highways and the increase of vehicle speed and the increasing traffic density, in order to ensure the safety of driving, the reliability of vehicle brake system is becoming more and more important. Only with the good brake performance and reliable work of the brake system can the vehicle make give full play to its dynamic performance.

This thesis will design the brake system based on the basic parameters of the micro electric vehicle Dongfeng Fengshen E30L. The main contents include: analyze the

structure type of micro-pure electric brake system and its components; determination of the structure design program of the vehicle brake system and its components;determination of the technical parameters of the brake system and its components; analysis and calculation of the brake system and its components; determination of the specific structure parameters of the brake system and its components.

Key Words: micro-pure electric vehicle, brake system, disc brakes, drum brakes

Chapter 1 Introduction