Graduation Design (Dissertation) of Wuhan University of Technology

Design of Braking System for Small Electric Scooter

College (Department)： International Education College

Specialty amp; Class: Vehicle Engineering gj1303

Student Name： Ma Chao

Tutor： Guo Wei

Statement of Originality

I solemnly declare that the thesis I submit is a piece of writing I completed independently based on my own research under the guidance of my supervisor. Except for the quotations, this paper does not include any writings published or completed by other individuals or groups. I am fully aware that the legal consequences of this statement are borne by me.

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Abstract

Disc brakes are the object of this design, referring to the Smart for 4 model select parameters. In the part of the design of the braking system, designing and calculating the brake system at first, and the material, structure and size of the brake system parts were selected. The checking calculation of wear, temperature and parking was carried out. After that, the parking brake is designed and checked, and then the brake drive mechanism was selected and related calculations were carried out. After that is checking the braking performance, and then the brake force distribution curve and the brake force distribution coefficient curve of the front and rear wheel brakes are plotted according to the data obtained before by using MATLAB. In addition to software analysis, the three-dimensional models and assembly of the designed parts are first designed by CATIA. After that, the static analysis, modal analysis and thermal analysis of the model was carried out by ANSYS Workbench.

Key Words：blade electric vehicles; disc brake; MATLAB; CATIA;

ANSYS Workbench

Catalog

Chapter 1 Introduction 1

1.1 Foreword 1

1.2 Research status of automobile brake system 1

1.3 Research results of braking system for electric vehicle 2

1.4 Overview of Braking System Form 4

1.5 Design content 4

Chapter 2 Automobile Parameter and Brake System Layout 5

2.1 Automobile parameter 5

2.1.1 Selection of vehicle basic parameter 5

2.1.1 Calculation of relative parameter 5

2.2 Overall layout of braking system 6

2.3 Selection of brake 7

2.3.1 Classification of brakes 7

2.3.3 Selection of brake type 8

2.4 Summary 9

Chapter 3 Calculation of Brake System 10

3.1 Theoretical calculation 10

3.1.1 Braking force and braking distribution coefficient 10

3.1.2 Synchronous adhesion coefficient 11

3.1.3 Braking strength and utilization ratio of adhesion coefficient 11

3.1.4 Maximum braking torque of brake 12

3.1.5 Brake coefficient 12

3.2 Brake related calculation 13

3.2.1 Selection and size of basic parts of disc brake 13

3.2.2 Calculation of wear characteristics of friction linings 15

3.2.3 Calculation of heat capacity and temperature rise of brake 16

3.2.4 Calculation of braking torque of disc brake 17

3.3 Parking brake calculation 18

3.3.1 Parking brake type selection 18

3.3.2 Slope performance check 19

3.3.3 Maximum parking braking torque check 20

3.3.3 Brake handle tension check 20

3.3.5 Brake handle Stroke check 20

3.4 Correlation calculation of brake drive mechanism 20

3.4.1 Selection of brake actuating mechanism 20

3.4.2 Selection of brake piping system 21

3.4.3 Design and calculation of hydraulic brake actuating mechanism 21

3.5 Braking performance analysis 23

3.5.1 Braking efficiency 23

3.5.2 Constancy of braking efficiency 23

3.5.4 Analysis of brake force distribution curve 24

3.6 Summary 25

Chapter 4 Model Establishment and Analysis 27

4.1 Establishment of brake system model 27

4.2 Finite element analysis of braking plate 28

4.2.1 Pre-processing 28

4.2.2 Static Analysis 29

4.2.3 Modal analysis 30

4.3 Finite element analysis of braking caliper 32

4.3.1 Pre-processing 32

4.3.2 Static Analysis 33

4.4 Summary 34

Chapter 5 Conclusion and Prospect 35

5.1 Conclusion 35

5.2 Expectation 35

Reference 36

Appendix 38

Thank 39

Chapter 1 Introduction

1.1 Foreword

In the twenty-first Century, the development and maturity of the automobile industry played an important role in promoting the development of the world economy. But the side effects of automobile industry is also very loud, the development of the automobile industry also have to face many social problems, such as energy shortage, environmental pollution etc. Therefore, "safety, energy saving and environmental protection" has become the three major themes of the world automotive industry^[8]. The automobile brake system is one of the important systems of the automobile chassis, which restricts the movement of the automobile. The brake, as a direct acting brake system, is one of the most important safety parts in the automobile. The braking performance of a vehicle is related to the driving safety. With the increasing demand for safety and reliability, the improvement of braking system of an automobile is especially important^[19].

In the development of pure electric vehicles, the braking system, which determines its active safety and energy recovery, is the core of the goal of achieving the modernization of blade electric vehicles. The braking system of the blade electric vehicle bears the high demand and expectation of the society for the automobile products^[7].