全文总字数：11980字

1. 研究目的与意义（文献综述）

Ⅰ.research background and significance

electricvehicles are powered by renewable clean energy, which overcomes the problems ofenvironmental pollution and resource shortage of traditional internalcombustion engines; electric vehicle traction motors have a wider working rangethan traditional internal combustion engines, and the characteristics oflow-speed constant torque and high-speed constant power of the motor are moresuitable for vehicle operation needs.

theoperating speed range of the fuel car's engine is relatively narrow, and thevehicle needs to adjust the reduction ratio through gear shifting whiledriving, so as to keep the engine speed in a reasonable working range. comparedwith traditional cars, pure electric vehicles have eliminated the engine andtransmission mechanism. there have been changes. depending on the drivingmethod, some components have been simplified or cancelled, and new structuressuch as the power supply system and the motor have been added. due to the widerworking range of the motor, it can also output a large amount of torque at lowspeeds. at present, mostelectric cars adopt the architecture of single-stage reducer matched byelectric motors. adopt fixed reduction ratio of the driving mode can meet therequirements of the vast majority of the electric car to power performance, butmay lead to working in low efficient area for a long time, so the secondary gearreducer is used in helping the motor work in high efficient speed range as faras possible, thus to reduce losses, improve the effect of range, the economy isalso guaranteed on the premise of meeting the dynamic performance.

1.1research status in china

domestictransmission manufacturers have also invested a lot of research and developmentefforts and achieved certain results. chen qi of hefei university of technologyand other traditional dynamic simulation studies of two-speed transmissions ofpure electric vehicles^[1];wang wenjun of beijing institute of technology and others analyzed thetransmission for dynamics and matching of traditional systems. a two-speedtransmission for an electric vehicle was designed. its transmission method wasanalyzed and its control system was optimized using flc and an optimal controlalgorithm^[3]. chenlinyong et al. the two-speed mechanical automatic transmission structure forpure electric vehicles and the software and hardware design of the electroniccontrol unit^[12].

2. 研究的基本内容与方案

Ⅱ. basic content of the study,proposed technical solutions and measures

2.1 basic research contents and goals

1. designand calculation of vehicle dynamics and economy; complete the matching ofdriving motor parameters: the driving motor of electric vehicles requires hightorque at low speeds or climbing, high power output at high speeds, and a largevariable speed range. according to thevehicle parameters and design performance requirements, design the parametersof the rated power, peak power, maximum torque and maximum speed of the drivemotor; determine the speed ratio of the two-speed reducer: the first-speedspeed ratio must meet the car climbing requirements while making the low-speedmotor as much as possible running in the high-efficiency zone, while the secondgear meets the maximum speed, the speed of the motor's input shaft should bereduced as much as possible, and the high-speed motor should run in thehigh-efficiency zone as much as possible;

2. designof the transmission structure plan: determine the reducer layout plan, designand make the transmission schematic diagram, clarify the working principle ofeach gear, determine the gear type and shift structure type

3. designand calculation of transmission parts: determine the overall size of thetransmission according to the layout plan of the transmission; design andcalculate the gear part parameters (number of teeth, modulus, pressure angle,etc. of gears), shaft and bearing part parameters; complete the design ofsynchronizer and shifting mechanism;

   剩余内容已隐藏，您需要先支付后才能查看该篇文章全部内容！

   3. 研究计划与安排

   Ⅲ. schedule

   1~2(18-19 weeks of 7 semesters): determine the graduation project topics, improvethe graduation design task book (relevant parameters), and collect data insideand outside the school;

   3~4(weeks 1-2 of 8 semesters): scheme idea, literature search, and complete report;

   5(week 3 of 8 semesters): foreign language translation and data collection;

   剩余内容已隐藏，您需要先支付后才能查看该篇文章全部内容！

   4. 参考文献（12篇以上）

   Ⅳ. references

   [1] liu zhenjun, cui rongbin, zhaojiangling, shi bo. research and design of two-speed transmission for pureelectric vehicles [j]. chongqing: journal of chongqing university oftechnology, 2014.

   [2] yin pengfei. design andsimulation analysis of two-speed automatic transmission for electric vehicles[d]. harbin: master's degree in automotive engineering, harbin institute oftechnology, 2015.

   [3] xia zhibin. design anddevelopment of two-speed transmission for electric vehicles [j]. hunan:automotive practical technology, 2014.

   剩余内容已隐藏，您需要先支付 10元 才能查看该篇文章全部内容！立即支付