全文总字数：21865字

1. 研究目的与意义（文献综述）

1.1purposeand significance

with the rapiddevelopment of society and people's pursuit of quality life, higherrequirements have been placed on the performance of vehicles, especially withgood handling stability and driving smoothness, in order to meet the market andconsumers' requirements for the current development of the automotive industry demand.suspension is the general name of allforce transmission connection devices between the axle (or wheel) and the frame(or load-bearing body). the main function of the suspension system is toalleviate the impact of the road on the vehicle, attenuate the vibrationbetween the body and the wheel, transfer the force between the wheel and theroad, control the movement posture of the wheel and the body, and ensure thenormal driving of the car. as an important part of the chassis, the suspensionsystem has an important impact on the car's driving safety, driving comfort,handling stability and sports performance. according to the independence ofleft and right wheel movement when the wheel is subjected to road vibrationshock, generally speaking, suspension systems are divided into two categories:independent suspension and non-independent suspension. in recent years, atorsion beam suspension known as a semi-independent suspension has been widelyused in the rear suspension system of small and medium-sized passenger cars dueto its simple structure, convenient installation and positioning, and lowmanufacturing cost.^[13]

the suspensionsystem is an important part of the automobile chassis system, which bears andtransmits various forces and torques between the axle (or wheel) and the frame(or load-bearing body), alleviates the impact of the road surface and damps thevibration caused by the road surface excitation, which has an important impacton the safety, comfort and performance of the vehicle. while the tire isdirectly in contact with the ground, and at the same time, it bears the load ofthe entire vehicle bridge. through the joint action with the suspension systemto ensure its adhesion with the road surface, it provides the necessary drivingforce, braking force and lateral force when the vehicle is running. itsperformance directly determines the vehicle's handling stability and ridecomfort. the wear in the use of tires will reduce the performance of tires, andthe suspension performance will directly affect the wear of tires. ^[6] if the car adopts torsion beam rear suspension, the axle load of its rear axleand the impact of road surface are mainly borne by the torsion beam, and thetorsion beam part often needs to control the wheel runout and body roll throughdeformation, resulting in poor working conditions. if cars use torsion beamrear suspension, its front suspension is limited by the installation space,most of the choice of classic mcpherson suspension, because mcphersonsuspension structure variability is small, the performance of the whole vehiclesuspension system, mainly depends on the motion characteristics of the torsionbeam rear suspension. ^[13]

2. 研究的基本内容与方案

2.1maincontent

this subjectbelongs to the design category, and the main work is to design the rear torsionbeam type non-independent suspension of shanghai volkswagen lavida sedanaccording to the given vehicle parameters. specific tasks include:① graspthe composition and function of the rear torsion beam type non-independentsuspension system of shanghai volkswagen lavida sedan;② designand check each component of the suspension;③consider the connection relationship between each component in detail;④calculate suspension natural vibration frequency, suspension static deflectionand dynamic deflection, and suspension elastic characteristics.

2.2objectives

3. 研究计划与安排

1(20th week of 7 semesters) Determine graduation project topics, improvegraduation project assignments (relevant parameters), and collect materials oncampus2 (1st week of 8 semesters) Scheme idea, literature search, completion report3-4 (weeks 2-3 of 8 semesters) Foreign language translation and data collection5 ~ 7 (4-6 weeks of 8 semesters) Design calculations, sketches, and answerquestions8 ~ 10 (7-9 weeks of 8 semesters) Drawing, writing design calculationinstructions (thesis), pre-defense11 ~ 13 (10-12 weeks of 8 semesters) Arrangement of drawings and design calculationinstructions, arrangement of information bags, and examination of defense14 (13th week of 8 semesters) Students apply for defense and prepare fordefense; teachers review drawings and instructions15 ~ 16 (14-15 weeks of 8 semesters) Participate in a reply

4. 参考文献（12篇以上）

[1] jia hongwei. development of the reartorsion beam suspension system architecture of a car [d]. nanjing university ofscience and technology, 2018.

[2] huo yingchun. fatigue life simulationanalysis and structural improvement of a torsion beam rear suspension [d].yanshan university, 2017.

[3] mei guanghuan. analysis of suspensionmatching design of a suv car based on dynamic simulation [d].xihuauniversity,2017.