Reliability Research For Gear-box Of Commercial Vehicle

The gearbox is one of the important parts of automobile assemblies, worktogether with the engine, through different transmission ratio gear meshing, realize thedriving force of the engine and the speed ratio change, adapt to the automobile speedchanging driving conditions. The reliability of transmission is the main factor directlyaffecting automobile security.In this dissertation, Commercial vehicle with CA10TA gearbox is used as amodel to analyze the reliability of transmission. A great deal failure maintenance datais collected and analyzed from the first failures of the transmission in terms of themethod of recognizing reliable model and estimation of parameter. BP neural networkis widely used in the field of pattern recognition, it has good fault tolerance, selflearning ability and nonlinear mapping ability, but the algorithm depends on the initialweights of the selection, the slow convergence rate and easily falling into localminimum point. In order to improve the efficiency and accuracy of modelidentification, Select the PSO-BP network as the model identification, with the help ofpowerful toolboxes of MATLAB, I designed two model-recognizing systems based onBP and PSO-BP networks, and it is proven that the PSO-BP method converges faster,more accurate prediction. The first failures mileage accords with Weibull distribution.The curve of reliability and the parameter can be got from the Madaline neuralnetwork. With the same method, the reliability of the all parts of transmission caneasily to be analyzed and evaluated.According to the construction and work characteristics of this gearbox, this paperdecided to divided whole transmission into5systems. Including Pneumatic system,Manual Control system, Variable speed transmission system, electronic system andother parts of body. At the same time, this paper established failure part code, failuremodes and their codes, failure sources and their codes. By fault modes, effects andcriticality analysis according to the collected fault data, it gets that the mostmultifarious fault parts of the transmission and the weak link, put forward someprobable improvement measures for the weak link. In the other hand, this paper alsoput forward some other measures for the presses to provide material in the design,manufacturing, assemble and maintenance to the personnel in work. Combinedautomotive mechanical transmission bench test methods and analyzing, added to four bench test projects. Additionally, analyzed the Daily inspection projects and Factoryinspection items.This paper analyzed the reliability of the gearbox, evaluated the transmissionsystem and the various parts of the case, put forward appropriate and reliabilityimprovement measures for the gearbox to improve the commercial vehicle handlingand safety performance.