Graduation Design (Dissertation) of Wuhan University of Technology

Design of Manual Transmission of 6490 Light Bus

College : Institute of International Education

Specialty amp; Class: Vehicle Engineering gj1303

Student name: Xia Menghan

Tutor: Qiao Weigao

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.

Signature of the author:Xia Menghan

Date: 5.22

Copyright Letter of Authorization to The Dissertation

The author of this dissertation fully understands provisions stipulated by this school on keeping and using dissertations. The author agrees that the school can reserve and send photocopies and electronic versions of this thesis to relevant departments or institutions managing dissertations. This thesis can be read and borrowed. I hereby authorize excellent provincial institutions appraising bachelor dissertations to incorporate all or any part of this dissertation into relevant databases for retrieval, as well as to preserve and compile this dissertation by photocopying, scanning or reprinting it in a reduced format.

This dissertation is: 1. Confidential until(year) and then this authorization letter will apply. 囗

2. Non-confidential. 囗

(Please tick "√" the corresponding box above)

Signature of the author:Xia Menghan

Date:5.22

Signature of the tutor: Xia Menghan

Abstract

The design task is to design a manual transmission on a 6490 light passenger car. This is the use of intermediate shaft transmission, which relative to the automatic transmission has two outstanding advantages: First, the direct transmission of high efficiency; Second, you can get a larger gear ratio.Reference to the same type of engine models suitable for the car can be the maximum power of the engine, the maximum torque and the corresponding speed or other important parameters. Combined with the basic parameters of some cars, which is the length of 4.9 meters of passenger cars, you can choose the appropriate main reduction ratio.. According to the above parameters, combined with the transmission design manual, automotive design, transmission and reducer design and other related knowledge,you can calculate the relevant transmission parameters and check the design parameters.The transmission is used to change the engine to the drive shaft torque and speed. It can change the drive ratio of output shaft and input shaft , which is the car's energy conversion station. Its purpose is to make the car get a different driving force and drive speed when it start in place, climbing, turning, speeding, overtaking and other conditions. While the engine in the most appropriate range of work,or in special circumstances also has a power output function, that is the use of power to obtain the driving force from the transmission to the special machinery. The transmission used in this time has five forward gears (not including overdrive) and a reverse gear and uses a lock ring synchronizer to achieve the shift.

Keywords: Transmission; Lock ring synchronizer; Intermediate shaft

Catalog

Chapter 1 Overview of Mechanical Transmission and Determination of Its Solution 1

1.1 The function and requirements of the transmission 2

1.2 Determination of transmission structure scheme 3

1.2.1 Selection of transmission type 3

1.2.2 reverse transmission program 6

1.3 Analysis of Main Parts Structure of Transmission 7

1.3.1 gear type 7

1.3.2 Shift structure type 7

1.3.3 anti-automatic escape device 8

Chapter 2 Selection of Main Parameters of Transmission and Design of Main Parts 9

2.1 The choice of the main parameters of the transmission 9

2.1.1 Number of gears and gear ratio 9

2.1.2 Center distance 10

2.1.3 Axial dimensions 10

2.1.4 Gear parameters 11

2.2 file transmission ratio and the number of gear teeth to determine 12

2.2.1 Determine the number of gears for gears 12

2.2.3. Determine the number of teeth in other gears 13

2.2.4. Determine the number of teeth of the reverse gear 14

2.3 Selection of gear displacement coefficient 14

Chapter 3 Calculation of Strength of Transmission Gear and Material Selection 16

3.1 Cause and form of gear damage 16

3.2 Calculation and verification of gear strength 16

3.2.1 Calculation of gear bending strength 17

Straight gear bending stress 17

3.2.2 Gear contact stress 18

Chapter 4 Calculation and verification of the strength of the transmission shaft 20

4.1 Structure and dimensions of the transmission shaft 20

4.1.1 The structure of the shaft 20

4.1.2 Determine the size of the shaft 20

4.2 Check the axis 21

4.2.1 Strength and stiffness check of the first axis 21

4.2.2 Calculation of the second axis and the countershaft 22

Chapter 5 Selection of bearings 27

5.1 transmission bearing selection 27

5.2 Calculate the bearing equivalent dynamic load 27

5.3 Calculate bearing life 29

Chapter 6 Synchronizer Selection 30

6.1 Structure of the synchronizer 30

6.1.1 Friction factors 31

6.1.2 close to the size of b 31

6.1.3 scale size a 31

6.1.4 slider rotation distance c 31

6.2. Determination of Main Parameters of Synchronous Ring 31

Chapter 7 Transmission of the transmission 35

Chapter 8 Conclusion 36

Reference 37

Appendices...................................................................................................................38

Thanks..............................................................................................................................................39

Chapter 1 Overview of Mechanical Transmission and Determination of Its Solution

In the widespread use of automatic car today, Due to the development of technology and high performance requirements of the car, manual transmission market share gradually reduced, but also gradually by the manual transmission to the automatic transmission transition. But MT directly affect the power of the car, economy, handling stability, has its short time can not be exceeded the advantages. Compared to the automatic transmission, MT is slightly technical in the operation.But it can give the car driver a very good pleasure. Because the MT is by the gear drive, its performance is better than the automatic transmission for the transmission efficiency and fuel economy. In terms of power MT is also stronger than the automatic transmission, allowing the car to accelerate overtaking in a short time. In addition, after years of research all aspects of technology are very mature from the development of manual transmission, and the costs of manufacturing and maintenance are also reduced. On the one hand ,it does not meet the concept of modern lightweight car,because of its large volume of compressed car’s space . On the other hand, the greater impact give the driver experience at the same time and it also give the driver's operation inconvenience when MT is in the shift.

In general, the trend of manual transmission is: the decline in market share has become inevitable. Because of the advantages of cost and fuel consumption and growth in the high-end market segments, MT annual production will remain slightly increased, with its Absolute base is huge, MT's annual output is still considerable. In addition,for the guidance of high-tech industry and the transformation of consumer groups thinking, manual transmission will rely on the development of industrial age climax to high-performance and high-quality direction.