| The production volume of commercial vehicle in China was3,748,100in2012,accounting for17.79%of the global commercial vehicle production volume of21,071,700[1]. The continuous increase of the international automobile production and ownership, hasplayed a huge boost role in the growth of world economy, but also caused great negativeimpact on the global energy shortage and environmental pollution. In response to this crisis,the global automotive industry regards reducing fuel consumption and emissions, andimproving vehicle safety and reliability as the main objectives of the current work.Transmission is the most important components of the automotive driveline, so theimprovement of the gearbox design methods, the enhancement of the transmission reliability,and the reduction of the product development cost play a significant role in realizing thesegoals.The production of China’s heavy-duty vehicles has exceeded1million, and the qualityhas also been improved more than the last century. But comparing with that of the productsfrom the United States, Germany, Sweden, France and other advanced countries, a large gapof performance, quality, technology, reliability still exists. Likewise, in the area of the heavyvehicle transmission, compared with ZF(Germany), VOLVO(Sweden),and EATON (USA),a large gap still exists. The backward design method of transmission is one of the mostimportant reasons, in addition to the low manufacturing level of some parts.As a technical method for analyzing, deduction, and presenting preventative measuresfor the potential problems during product development, FMEA was applied in the aviationand aerospace field in early1950s in the United States and began to enter the automotiveindustry in late1970s. With the promotion and continuous improvement of U.S. Big Threeauto companies as Chrysler, Ford, and GM, FMEA has got the recognition of theinternational automobile manufacturers, and has becoming an efficient design method for thedevelopment of automotive product.Taking a CNHTC heavy-duty transmission model as an example, this thesis has setclear the definition of the failure, discussed about the main function, the scope andimplementation process of FMEA, studied and analyzed the technicla features, qualityindicators, manufacturing feasibility and other aspects of the potential failure modes, alsostudied the consequences and damage degree of the potential failures, in particular of thecomponents related to automotive safety and compliance with laws and regulations, put forward effective measures which can be used to prevent, evaluate and validate failuremodes.Research results of this thesis have improved the new ideas and methods about applyingDFMEA in the development of a heavy-duty vehicle transmission. Since we have got inputfrom heavy-duty transmission with multi-gears, high torque and full synchronizing ofCNHTC Datong Gear Company during the study, the research results have higher practicalvalue and can be directly applied to performance optimization of the old heavy-dutytransmission and the development and of the new product. |
