| With the rapid development of national economy, automobile is widely used in the modern economic and social work, daily life and leisure travel. Transmission as the power transmission device on the car, its operational reliability is closely related to the vehicle's normal operation and safety. Because the road surface condition of automobile travelling is complicated, and gears change frequently, transmission often malfunction or fail due to fatigue. Its will affect automobile normal driving, and may lead to traffic accidents or cause casualties. Therefore, carrying out the reliability research about automobile transmission is extremely important. It is of great significance for improving the automobile's performance and ensuring automobile's driving safety.This article embarks from the practical engineering application, and is based on studying the typical structure and each part function principle of the automobile transmission, then draws the diagram of the system structure and function, analyses the reliability of key parts, establishes the system reliability model. On the basis of it, applicating the positive FTF method of combining FMECA and FTA to carry out automobile transmission reliability analysis work. It analysis the main failure mode of automobile transmission may occur and its causes and effects, lists the FMECA worksheet of transmission, then orders and analysis all listed failure mode by the method of qualitative harmfulness matrix diagram, determines the key failure mode and weak links of transmission, and puts forward the corresponding compensation measures and Suggestions for improvement. Contraposing the serious consequences of system failure, using it as the top event to establish the fault tree by the method of FTA, then proceeing fault tree qualitative analysis, Pointting out the internal relationship between spare parts fault and system fault, finding out the the main factors of causing system failure and influencing the normal work of transmission. Then proceeing comprehensive reliability analysis, Summarizing the main failure mode and cause of automobile transmission.On the basis of reliability analysis, this paper studies the automobile transmission reliability test methods, determines the test load and loading mode of transmission reliability test, then designs the transmission reliability test bench, determins the specific implementation plan, test specifications, test failure criterion and the method of monitoring and recording data in the test process. Contraposing the experimental data obtained, discussing the data processing method, analysising and get the test transmission reliability index by using weibull distribution.This article through establishing a complete set reliability analysis work of analysis-test-feedback-update complete analysis and design,to provides reference and basis for automobile transmission system design and improvement. |
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