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1. 研究目的与意义（文献综述）

Transmission is a key partof the power transmission system, it can not only reflect the performance andfuel economy of vehicles, but also change the working efficiency of the engine,it can smoothly change the transmission ratio, transmit the input shaft torqueto the output shaft, make the engine under various conditions to keep normaloperation, improve work efficiency and transmission efficiency. According tothe transmission ratio changes in different ways, the transmission can bedivided into three types of pole type, non-pole type and comprehensive type.According to the different operation mode, it can be divided into three kinds:forced operation type, automatic operation type and semi-automatic operationtype. More commonly used is the ordinary gear transmission, usually will alsocooperate with the use of synchronizer, synchronizer can make the transmissionin the process of car driving shift does not occur impact. In our county,starting in the 1950 s, equipped with a hydraulic automatic transmission carsbecame popular, their Numbers have rising trend, at present, the steplesstransmission has become mainstream, hydraulic stepless transmission andmechanical stepless transmission is used widely in the car, electronictechnology development is relatively mature, hydraulic automatic transmissionalso entered the new period of development, its structure is more and moresimple, compact, and it can significantly improve the vehicle's fuel economyand power performance, not only can reduce the fatigue of the driver, also canreduce the vehicle's shift shock, has high service life, the advantages ofsimple operation, less pollution.[1] From the research status athome and abroad, hydraulic automatic transmission is the most completedevelopment, the most mature technology and the most widely used automatictransmission. With the continuous development of science, technology andinformation technology, people's awareness of environmental protection isconstantly enhanced, and the automobile industry is gradually moving towardsthe direction of intelligence, automation and electric development.[2] Thusfor traditional auto transmission put forward the new requirements ofdevelopment, people also constantly improve the demand for car performance,transmission manufacturers around the world are developing all aspects of thetransmission of improvement, development and innovation, so that thetransmission can get better application in the vehicles, its comprehensiveperformance will gradually increase, this has become an important symbol ofmodern automobile and industrial development. In order to ensure that thetransmission has good performance, it is necessary to design the parameters ofthe transmission reasonably and improve the traditional power transmission anddrive technology. Future should from the optimized design, high integration,seiko manufacturing, etc of the auto transmission control energy consumptionand sensing precision is promoted, with the development trend of automotivemainstream at the same time pay attention to play to the integration of thetransmission cost advantage, and constantly develop a more economical and practicalnew technology of automotive transmission, improving the overall of theautomobile drive performance, improve vehicle drivers driving comfort. [3] dueto the continuous innovation and development of science and technology,transmission design technology has been comprehensively optimized, in theprocess of automotive mechanical transmission design, should be combined withthe modern design, so as to improve the transmission performance.

2. 研究的基本内容与方案

In the process of thespecific design work, need to pay much attention to its own weight, materialsused and the transmission on the premise of quality factors, reduce the weightof gear and shaft, in quality at the same time, the performance of ascension,as far as possible to reduce noise when the gear mesh, also hope that thetransmission can be more nimble and main measures are: reasonable quantityincrease transmission gear design, make the engine play the maximum power canbe obtained. In the transmission gear number design, should be combined withthe specific use of the car. At the same time, the transmission ratio isclosely related to the use conditions and parameters of cars. The transmissionratio of cars is generally maintained between 2 and 5, that of minivans between6 and 8, and that of trucks with large load will be higher. Therefore, in thedesign process, should be combined with the specific use of the car, so as toensure that the basic transmission performance remains unchanged. [4] Ingear design, the more modules should be used to control the modulus andpressure Angle of the gear, the higher the thickness will be. When selectingthe pressure Angle, it should be combined with the motion direction of theinvolute. Only by ensuring that the width and spiral Angle of the gear conformto the standard and the degree of inclination is fully controlled, can theadvantages of the gear be brought into full play and the load capacity of thewhole gear structure be improved. Control the number of gear teeth anddisplacement coefficient, if the number of gear teeth is too small, it willaffect the engagement between the gear, reduce the stability of the main drive.In the process of gear parameter design, the key factor of transmission designis to ensure that the gear design conforms to the standard. The overall qualityof the transmission is directly related to the gear performance. In order toensure that the transmission design standard is improved, scientific geardesign is very important.

3. 研究计划与安排

4. 参考文献（12篇以上）

文献检索

[1] 史文库,姚为民. 汽车构造（第六版）[m]. 北京；人民交通出版社, 2013.05.

变速器的功用是改变传动比，扩大驱动轮转矩和转速的变化范围，实现汽车倒退行驶，利用空档终短动力传输。变速器主要由变速传动机构和操纵机构组成，根据需要可加装动力输出器。按传动比变化方式不同，变速器可分为有极式、无极式和综合式三种。按操作方式不同又可分为强制操纵式、自动操纵式和半自动操纵式三种。比较常用的是普通齿轮变速器，通常还会配合同步器使用，同步器可以使变速器在汽车行驶过程中换挡不发生冲击。随着科技发展无级变速器成为主流，其中液力无级变速器和机械无级变速器在汽车上运用越来越广泛。