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1. 研究目的与意义（文献综述）

with the progress ofscience and technology and the development of economy, the automobile industryhas been greatly developed in the past hundred years, which has an immeasurableimpact on the development of global economy and the improvement of human livingstandards, leading to an epoch-making revolution. under the guidance of the cpccentral committee, since the reform and opening up 40 years ago, china'sautomobile industry has undergone tremendous changes, and china has become thelargest automobile manufacturer in the world. in 1978, china's automobileproduction was only 149000, accounting for 0.4% of the world's automobileproduction in that year. however, in 2017, china's auto production reached29.015 million, accounting for 29.8% of the world's auto production, becomingthe world's largest auto manufacturer for nine consecutive years. due to thecontinuous development of the automobile industry and the continuousoptimization of the automobile design, people have higher and higherrequirements for the performance of the automobile, such as themaneuverability, comfort, fuel economy, life cycle vibration and noise.therefore, it is not necessary to develop a transmission system with excellentperformance. in this kind of environment, if the automobile enterprises want tosurvive, they need to develop the transmission with excellent performance andhigh cost performance. at present, there are five major categories ofautomobile transmission products: manual transmission (mt), automatictransmission (at), manual automatic transmission (amt), stepless transmission(cvt) and dual clutch transmission (dct). among them, manual transmission isthe most widely used transmission in the world. compared with automatictransmission or self-contained transmission, manual transmission has theadvantages of high transmission efficiency, low purchase cost, low use cost andconvenient maintenance. 2018 data shows that in the global scope, manualtransmission still accounts for a large part of the total market sales, accountingfor about 68% of the total global sales. therefore, the development andimprovement of the existing manual transmission system, from market-orienteddevelopment to in-depth development, organization of refined production, lowcost, and improvement of product quality, has become the necessity in thecurrent market environment.

inorder to achieve these goals, in today's transmission design process, more andmore finite element analysis is used for preliminary development andtheoretical analysis, which greatly shortens the development cycle, reduces theexperimental cost and verifies the feasibility of the design. nowadays, thefinite element analysis software used in the automobile industry at home andabroad includes ansys, msc-nastran, hypermesh, abaqus, etc. for example, cfd(computational fluid dynamics) method is used in the paper "los angelesestimation of the roll over of manual transmission gearbox" in foreigncountries. one of the estimation methods is ansys fluent, which uses commercialcfd tools. with this new method and procedure, the roll over / splash loss ofthe entire manual transmission can be estimated. by establishing acomputational fluid dynamics model, the splash loss and wind speed loss of asingle gear are estimated. then a computational fluid dynamics model isestablished to estimate the sputtering loss of gear pair, including theinsertion power loss caused by the oil extrusion between gears. then theparameters of the gear pair are studied to determine the insertion underdifferent operating conditions, such as speed, temperature and the percentageof oil level for input loss. at last, a computational fluid dynamics method isproposed to estimate the sputtering loss of mt. considering the staticcharacteristics of the gearbox, the sputter loss of the gear immersed in oil isestimated, and the wind loss of the gear when it is separated from oil isestimated. in order to estimate the sputtering loss of gear pair, the loss ofeach gear is weighted, and the percentage of additional loss is calculated. bythis method, the loss is estimated, so that the transmission efficiency ishigher. the software specially used for transmission design includes romax andmasta, which have optimization functions. for example, romax software, which iswidely used in transmission design in china, can optimize the gear macroscopically.for example, under the condition of constant speed ratio, the weight of contactsafety factor and bending safety factor can be changed by optimizing the basicparameters of gear: helix angle, modulus and pressure angle, so as to improvethe coincidence degree, so as to improve the contact safety factor and bendingsafety of gear purpose of the coefficient. in addition, it can also carry outmicro modification on the gear, in the tooth shape and upward modification, soas to reduce the transmission error of the gear. therefore, in order to designthe transmission with better performance, we need to combine cad / caetechnology, give full play to the function of computer software, optimize theproduct design, and more process oriented to transmission design. we shouldexpand the optimization design to the optimization of the whole system, thewhole performance and the whole life cycle. it is to meet the needs of productdesign, technical development and modern scientific and technical support underthe new development of optimization design technology.

2. 研究的基本内容与方案

the basic content of the study is to take a light truck as theresearch object, design the overall scheme of its manual transmission, and usecad and cae technology to optimize the structure of the transmission, obtain atransmission with better performance, and explore a set of transmission designmethods.

it includes the following aspects:

(1) firstly, the design scheme of the light truck manualtransmission is determined, including the general arrangement form of gear andshaft, shift control mechanism and gear arrangement form, etc. according to thedesign goal of the transmission, the general arrangement is selected, and the structureof the transmission is analyzed.

3. 研究计划与安排

week 1 2: basedon reading comprehension and understanding of the current research situation athome and abroad, a general goal and direction are obtained, and an openingreport is completed.

week 3：collectand organize existing data, formulate a thesis outline, and complete thetranslation of foreign languages

week 4: prepare the opening defense

4. 参考文献（12篇以上）

[1] zhang shuguang. overall transmission scheme andshell optimization design of six speed manual transmission [d]. hunanuniversity, 2014

[2] wang zhihong. optimization of manualtransmission system and evaluation of shift quality [d]. wuhan university oftechnology, 2013

[3] tang chen. design and optimization of manualtransmission of minicar [d]. wuhan university of technology, 2010