1. 研究目的与意义（文献综述）

the main function of gearbox is passing the power generated by wind wheels under the action of wind power to electric generator and making it get corresponding rotational speed. it assumes an important role in mechanical parts of wind turbine generator set. generally, rotor speed is very low and far short of required speed of generators. that means,the appropriate speed must be obtained through the growth role of the gear pairs of gear box. therefore gearbox is also called step-up box. according to the overall layout，the transmission shaft attached directly to the rotor hub sometimes been integrated with gearbox. besides there is also a structure-macroaxis and gearbox are decorated respectively, using tight set of device or coupling to connect.in order to increase the braking abilities,braking devices are occasionally set in the input or output of gearbox, cooperating with the tip brakes(fixed pitch wind turbines)or variable pitch brakes to achieve joint braking purpose of transmission system.
because of being installed in the place with a drought like high mountains、wilderness、beaches and islands. the unit is influenced by irregular deflecting as well as load-changing wind and extreme difference in temperature.besides,it is extremely difficult to renovate if the malfunctions appear,because of the traffic inconvenience of its installation site and the small room of the installation of gear box in the tower top.therefore the requirements for its reliability and service life are much higher than general mechanical devices. for example,in terms of requirements for material, in addition to the normal conditions and mechanical properties, it should has resistance to cold brittle features under low temperature condition s;it should ensure the smooth working of gearbox and avoid vibration and impact;it should ensure adequate lubrication conditions and so on. in the area with high difference between summer and winter temperature. it is important to configure the appropriate heating and cooling device.besides, monitory sites should be arranged,in order to telecontrol the operation and lubrication conditions. different forms of wind power generators have different requirements, the layout of the gear box form and structure also varies accordingly. in wind power industry, fixed axis gear drive and planetary gear transmission is the most common in the horizontal axis wind turbine.

as mentioned above，wind power is affected by natural conditions. the emergence of some special weather conditions can lead to failure of wind generators. and narrow cabin may not like the ground which has a firm stand base.therefore factors which affect the transmission of power matching and torsional vibration are always reflected in a weak link.furthermore, a lot of practice has proved that this link is often set in the gear box. therefore, to strengthen the research of gear box and attach importance to its maintenance work are particularly important. in recent years, as individuals pay an increasing number of attention on wind power generation, wind power industry has obtained rapid development. at present, the horizontal axis wind turbine is still occupying the important position in the wind power generation. however as a result of high failure rate of wind power gear box, the key technology of wind power gear box design and manufacturing has been an important factor which plagues the development of wind power in china even all over the world. especially with the continuous increase of capacity of wind turbines, there are more and more factors to consider in large wind power gear box design and manufacturing. the rapid development of wind power industries contribute to the prosperity of the wind power equipment manufacturing industries.wind power gear box，as the core component of wind turbines, wins great attentions of the wind power industry and research institutions at home and abroad. but due to the relatively late start of domestic research of wind power gear box and the poor related technologies. especially the megawatt wind power gear box, rely mainly on the introduction of foreign technology. therefore, independent studied for the megawatt wind power gear box and really master wind gear box design and manufacturing technology, in order to realize the localization of wind turbine production are in urgent need.

the design must ensure that the structure simplification and the lightest weight,on the premise of meeting the reliability and life expectancy.cad optimization design assumes an significant role in scheduling optimum transmission scheme、choosing reasonable design parameter、choosing stable and reliable components as well as material which has good mechanical properties and remains stable under extreme temperature environment.

this paper is design and analysis for transmission system based on pro/engineer software and ansys finite element analysis software.

2. 研究的基本内容与方案

2.1 basic components

（1） structure design and calculation of wind turbine gearboxes.

according to the condition on the structure design, select the appropriate parameters by theory calculation.

3. 研究计划与安排

3、schedule

week 1( preliminary week): graduation design mobilization and topic selection

week 2 and week 3: off campus practice and information collection

4. 参考文献（12篇以上）

references

[1] 关立山.世界风力发电现状及展望全球科技经济嘹望[j]．全球科技经济嘹望，2004，15(7):51—55．