Wuhan University of Technology Graduation Design (Thesis)

Rear suspension design of dongfeng long-head diesel truck, model EQ1092F8AD1

School: School of International Education

Specialty amp; Class: Automotive Engineering gj1501

Name: Fang Yuchen

Tutor: Xiong Xin

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Abstract

My graduation design theme is the rear suspension design of dongfeng long-head diesel truck, model EQ1092F8AD1.

At present, the trucks listed in China mainly use non-independent suspension.The first step is to determine the structure of the rear suspension, and then select and calculate the main parameters of the suspension.Because there are many differences in the structural functions of the front and rear suspension, the most obvious difference between the rear suspension and the front suspension in the design process is that the rear suspension needs to distribute the stiffness of the main and auxiliary springs. After calculation, the stiffness distribution of the main spring and the auxiliary spring is represented by the elastic characteristic diagram.In addition, the main and auxiliary spring should be calculated separately to determine the main parameters, determine the length of each piece, check the strength, and calculate the assembly radius of curvature and arc height.

As the elastic component of the target suspension, leaf spring is the most important part in the design of truck suspension, which is of great significance to the driving and riding comfort, ride comfort, vibration reduction ability and suspension structure.

Key words: EQ1092F8AD1 leaf spring independent suspension

Content

1 Introduction 1

2 Determine the Basic Parameters of the Truck 2

2.1 Main design parameters 2

2.2 Number of axles of the truck 2

2.3 Driving type 2

2.4 Layout 2

2.5 Main dimensions of goods vehicles 3

2.5.1 Overall dimensions 3

2.5.2 Wheelbase L 4

2.5.3 Front and rear wheelbase 4

2.5.4 front suspension and rear suspension of the automobile 5

2.6 Truck quality parameters and axle load distribution 5

2.6.1 Vehicle readiness quality 5

2.6.2 Loading quality 5

2.6.3 Truck quality coefficient 6

2.6.4 Total mass of truck 6

2.6.5 Axis load distribution 6

2.6.6 height h of the center of mass of the truck 7

3 Determination of basic parameters of rear leaf spring suspension 8

3.1 suspension static deflection 8

3.2 Suspension dynamic deflection 9

3.3 Elastic characteristics of the suspension 9

3.4 Stiffness distribution of main and auxiliary springs of rear suspension 10

3.5 Selection of main parts and components of the suspension system 12

3.5.1 Connection form between leaf spring and frame 12

3.5.2 Spring clamp 12

3.5.3 leaf spring center bolt 12

4 Design of elastic components 14

4.1 layout of leaf springs 14

4.2 Determination of main parameters of leaf spring 14

4.2.1 Full arc height 15

4.2.2 Determination of leaf spring length L 15

4.2.3 Determination of section size and number of steel plates 16

4.3 Determination of leaf spring length 18

4.4 Determination of bearing type of leaf spring end 19

5 Conclusion 26

Reference 27

Appendix A 28

Appendix B 29

Acknowledgement 30

1 Introduction

The suspension is one of the most critical assemblies in a modern automobile, and it connects the frame (or body) with the axle (or wheel) flexibly. Its main task is to transfer all the force and torque between the wheels and the frame, and mitigate the impact load from uneven road surface to the frame (or body),attenuate the vibration of the bearing system caused by this, to ensure the smooth running of the car. Due to the advantages of simple structure, easy maintenance, and the use of various types of elastic components, the non-independent suspension is widely used in the front and rear suspension of domestic truck and buses. There are a number of all-wheel-drive multi-purpose vehicles on the market that also use non-independent suspension as their front and rear suspension.With the development of design and manufacturing technology of elastic components, shock absorbers and other structural parts, the performance of non-independent suspension is improving day by day.In the high-grade model of a few large quantities of production, sporty car, after suspension still USES not independent suspension.Most of the light trucks are front drive, for this type of vehicles, the rear axle does not have a large mass of the main reducer and differential, the use of non-independent suspension or independent suspension, the mass of non-suspension does not change significantly, so the non-independent after the suspension of the application prospect is wide.When the car is running on uneven road surface, vertical vibration is produced due to the elastic action of the suspension.In order to quickly attenuate the vertical vibration, suppress the resonance between the car body and the wheel, and reduce the amplitude of the wheel, the suspension should be equipped with shock absorber, so that it has a reasonable damping.By using the damping effect of the shock absorber, the vibration amplitude of the vehicle is continuously reduced until the vibration stops.

The theme of this graduation project is the rear suspension design of dongfeng long-head diesel truck, model EQ1092F8AD1.Its rear suspension design, that is, leaf spring rear suspension design.According to the actual road environment and actual load, the suspension was redesigned to improve the driving smoothness and handling stability of the truck on the mountain road with bad road conditions.According to the actual loading quality of the truck, the force analysis and check are carried out on the elastic components and related parts of the suspension to improve the service life of the suspension.

2 Determine the Basic Parameters of the Truck