摘 要

本次设计是中型货车驱动桥的设计，驱动桥是汽车传动系统的重要部分，位于驱动链的末端,它的作用是提高转矩并将转矩传递到车轮和实现两车轮的差速功能.驱动桥作为汽车四大总成之一，它的性能的好坏直接影响整车性能，而对于载重汽车显得尤为重要.当采用大功率发动机输出大的转矩以满足目前载重汽车的快速、重载的高效率、高效益的需要时，必须要搭配一个高效、可靠的驱动桥.

关键字：载重汽车 驱动桥 单级减速桥 弧齿锥齿轮

Abstract

This is the design of the medium truck drive axle. The drive axle is an important component of the automotive transmission system, located at the end of the drive train. Its function is to increase the transmission shaft or transmission torque, passing it to the drive wheel and making it have a differential function. Driving axle as one of the four major assembly car, its performance is a direct impact on vehicle performance, for the truck is particularly important. Using high-power engine output torque to meet the current fast, heavy load of high-efficiency, high efficiency needs, which must be with a highly efficient and reliable drive axle.

Key Words: medium truck；drive axle；single final drive final drive；the spiral bevel gear

Contents

摘要 1

Chapter1 Introduction 4

Chapter2 Type and arrangement of drive axle structure 6

2.1 Rigid drive axle 6

2.2 divided axle 6

2.3 Multiaxle drive 7

Chapter3 Final drive design 10

3.1 The structure of the Final drive 10

3.1.1 The gear type of the Final drive 10

3.1.2 Deceleration of the Final drive 10

3.1.3 Final drive and driven bevel gear support form 10

3.2 Selection and Design of Basic Parameters of final drive 11

3.2.1 Determination of driveaxle ratio 11

3.2.2 The load calculated on Final drive 12

3.2.2 Selection of basic parameters of Final drive 13

3.2.2.1 Driving and driven bevel gear teethand 13

3.2.2.2 Large end diametersand face modulus of Driving bevel gears 13

3.2.2.3 Selection of tooth width F of spiral bevel gear 14

3.2.2.4 Midpoint helical angle 14

3.2.2.5 Spiral direction 14

3.2.2.6 Normal pressure angle 14

3.2.3 Calculation of geometric dimensions of circular bevel gears for Final drive 15

3.2.5 Strength Calculation of Spiral Bevel Gear of Arc Gear of Final drive 17

3.2.5.1 Gear damage form and life 17

3.2.5.2 The circumferential force on the gear length of the main gear unit 19

3.2.5.3 Calculation of Bending Strength of Final drive Gear 19

3.2.5.4 Calculation of gear surface contact strength of gear 20

3.2.6 Materials and Heat Treatment of Final drive Gear 21

3.2.6.1 Calculation of Final drive bearings 21

3.2.6.2 Calculation of bearing load of Final drive 23

Chapter4 Differential design 27

4.1 Selection of differential structure type 27

4.2 Design of Symmetrical Cone Planetary Pinion Differential 27

4.2.1 Selection of Basic Parameters of Differential Gear 27

4.2.1.1 The choice of the number of differential gears 27

4.2.1.2 Determination of Spherical Radius of Planetary Pinion 27

4.2.1.3 Selection of Gear Number of Planetary Pinion and Axle Gear 28

4.2.1.4 The timing of the differential bevel gear is determined 28

4.2.2 Geometric Calculation of Differential Gear 29

4.3.3 Strength Calculation of Differential Gear 31

Chapter5 Design of the axle shaft 33

5.1 Determination of Loads for full floating axle shaft 33

5.2 The primary selection of the diameter of the shaft of the full floating axle shaft 34

5.3 Strength calculation of full floating axle shaft 34

5.4 Strength calculation of axle shaft spline 35

Chapter6 Design of axle housing 36

6.1 Structure type of axle housing 36

6.2 Force Analysis and Strength Calculation of axle housing 37

6.2.1 Static bending stress calculation of axle housing 37

6.2.2 Calculation of axle housing strength under load impacted impinging road surface 38

6.2.3 Calculation of axle housing strength in maximum driving traction 39

Conclusion 41

Acknowledgement 42

Reference 43

Chapter1 Introduction

The axle is located at the end of the drive train. Its basic function is to increase the twist, slow down, change the torque transmission direction, that is increased by the drive shaft or directly from the transmission of the torque, and the torque is reasonably allocated to the left and right drive wheels; But also bear the role of the road or body between the vertical force, vertical force and lateral force, as well as braking torque and reaction torque and so on. The drive axle is typically composed of Final drive, differential, wheel drive and axle housing.

The following basic requirements should be met when designing the axle:

1)Select the appropriate main final drive ratio to ensure that the car under the given conditions with the best power and fuel economy.