Study On The Application Of Modern Design Method For Automobile Manual Transmission

With the rapid development of sciense technology and violent competition of market step by step, modern automobile transmission design by using the represtative of CAD /CAE /CAM program will take the place of traditional design methed. With many design softwares of transmission appeared, these procedures always include part mode building, parameter choice, calculation dimension, finite element analysis, optimization part parameter, simulation, etc. By settig up dummy mainframe, it can reduce design-period and reduce design-cost. Taditional manual-design must be instead of computer assistance design. Modern computer application not only have previously assistance analysis calculation and assistance design, but also have optimization design, apposition design, three-dimensionality building mode, design-process manage, associating design with manufacture, dummy manufacture, etc. It is network and database tecnology applicatioin in design which prompts design process, improves design quality .It is very convenient for difference enterprises to transfer information.The function of transmission is change drive-wheel rotate-speed and torqer, so the automobile can get difference pull and speed, make engine work in a range .The transmission is very important part in automobile. The gear and shaft are important part in the transmission .So the gear and shaft is important to transmission design. The gear and shaft design always is complex, many parameters need repeat choice and calculate to adapt design requirement. Previously, some simple design caculation would consume much time, others was compexed, Such as modification coefficient choice, strongth of gear calculation. This article mainly introduce six-speed manual transmission design .By studying design process of Japanese hino,mitsubishi transmission ,British MASTA transmission, It realizes transmission computer assistant design by delphi program . This article's content includes comfirm first speed-rate by special condition.Because automobile working-condition,shift-time,using-time are all different, so it wastes fuel and transfers shift difficultly. Modern automobile theory considers that not only the smaller speed rate is, the ecnomicaler the fule consumes and the convienter the shift transfers, but the automobie mainly uses high speed shift and high speed shift is more than low speed shift, so the high speed rate should smallerthan the low, to adapt the situation above, according to the shifts transmit rate caculates and devides, then confirms the gear's quanlity, we choice the part's parameters by experience formula, caculate dimensions and check strenth by computer program, there are three ways in the strenth checking and contrast it.that is to say :the gear caculating way of Japanese hino, Japanese mitsubishi and the ISO's. The automobile transmission's main lose efficacy is gear crack, so this article devides the vary coefficient by the curve strenth balance theory, and checks strenth by drawing S-N curve. It describes the process of transmission transmiting system's caculating and makes the computer procedure. Meantime, it makes the computer procedure on the supporting atrenth, curve, curve strenth, transfer strenth and so on, it realizes the simplization of caculating. It improves the design effiency, reduces the design period, and improves the design accurary by really using.MATLAB is one of the excellent math software in the world,it's function is strenth and it's operation is simple, it contains three functions----data caculation, mark caculation and drawing visualization. MATLAB includes a series of optimization caculation function and it can caculate the minimum in constraint, then tradition design method uses the experience formulas and measures other transmission's parameters. The traditional design is often conserved and blind. The main aim that the designer persues is reducing volume, weight and improve transmitting ability in the field of automobile transmission design nowdays. Because it can reduce manufacture cost, decline transmit loading, improve gear life, and make the design convient. So, the persuing aim is volume's smallization in transmission's optimization design according to part strenth, using life and other condition. On the theory of traditional design, it can achieve idealistic effect by computer assistance design and optimization design.this article's main optimization aim is volume's smallization by Fmincon in MATLAB 6.5 optimization tool box, there are 19 parameters in this design, such as transmit rate, number of teeth module, helix angle, gear width etc. it established a optimization design model on transmit rate, gear quantity, spiral angle, gear width and other parameters throuth the constraint condition of experience parameters of traditional machenary truck transmission, it achieved a satisfied design effect.