Bachelor Degree Project of

Wuhan University of Technology

Structure Design of Secondary Star Transmission

学院（系）： 国际教育学院

专业班级： 车辆gj1303

学生姓名： 蒿珵

指导老师： 韩星会

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ABSTRACT

With the rapid development of the automobile industry and the increasing pollution problem of the environment, the development of electric vehicle has become a tendency. The design of electric vehicle reducer is one of the most essential keys for electric vehicle development and has a significant impact on the performance of electric vehicle. The paper is aimed to design a secondary planetary gear reducer for a distributed four-wheel drive electric vehicle, under the known conditions of the motor power, the input speed and the transmission ratio. The paper first determine the gear transmission types of the reducer, the distribution of the transmission ratio, the related parameters about all gears through calculation and check the strength of gears, then design the important structures in this transmission system such as shafts, gears, planetary frames. After that, build the 3D model of all parts, assemble them by using SOLIDWORKS software and do some simple finite element analysis of the output shaft by using ANSYS software. Finally, write the summary about the paper.

Key Words：Planetary gear transmission; reducer; structure design; check the strength; the finite element analysis.

Table of content

Abstract

Chapter 1 Introduction...................................................................................................1

1.1 Project background and significance....................................................................1

1.2 Foreign and domestic development......................................................................2

1.3 Project content......................................................................................................2

1.3.1 Design requirements .....................................................................................3

1.3.2 Problems should be solved in this design......................................................3

Chapter 2 Determine the Transmission Type.................................................................5

2.1 Type selection of gear transmission.....................................................................5

2.1.1 Two types of gear transmission.....................................................................5

2.1.2 Comparison of two types of gear transmission ......................................5

2.2 Type selection of planetary gear transmission.....................................................6

2.2.1 Different types of planetary gear transmission.............................................6

2.2.2 Choose the types of planetary gear transmission..........................................6

2.3 Transmission sketch of the design .......................................................................7

Chapter 3 Gear size design.............................................................................................8

3.1 Distribution of transmission ratio.........................................................................8

3.2 Determine the number of teeth of each gear.........................................................8

3.2.1 Determine the number of teeth by calculation..............................................8

3.2.2 Transmission ratio error checking.................................................................9