The Finite Element Analysis Of The Automobile Transmission Gears And Case

In recent years, as the number of domestic cars grow rapidly, auto parts have entered intoa period of high-speed development. Transmission is one of the most important parts ofautomotive transmission system. Through the change of transmission ratio, increase the speedand torque variation, cars can accommodate complex road conditions. The design oftransmission will directly influence the car’s dynamic, reliability, comfort, stability, etc.In this dissertation, taking the automobile transmission first gears and case as theresearch object, the contact stress of first gears in transmission was analyzed by finite elementmethod. The modal analysis and mode test of transmission case were implemented. The weakposition of the transmission case was found by the strength analysis of transmission caseunder four kinds of working conditions, including first drive, reverse drive, maximumsuspension force and minimum suspension force. On the basis of it, the improvementsuggestion was proposed to meet the design requirements. The study contents and results ofthis dissertation were as follows:Firstly, the three-dimensional entity models of first gears of the automobile transmissionwere created by CATIA and the tooth contact stress analysis of first gears of the transmissionwas performed by HYPERMESH and ABAQUS software. In the process of geartransmission, the distribution of contact line and contact stress on the tooth surface wereobtained. The results show that the maximum contact stress of first gears of this dual clutchtransmission are no more than the allowable stress of material and the strength of gears canmeet the design requirements.Secondly, the modal analysis of the transmission case was performed using finiteelement method and the experimental modal testing method of single-point excitation andmultipoint response. Each order natural frequency and vibration mode of the transmissionhousing were obtained and the results of the experiment and the simulation were compared.The results show that the maximum relative error is3.21%which is in the range ofpermissible error. It proves the finite element analysis of the transmission case is reliable andaccurate. It provides a basis for the structure design of the transmission case and the analysisof its vibration and noise.Finally, the casing strength analysis of transmission case was completed by finiteelement method. The stress distribution was obtained under different working conditions.Based on it, the weak position of the transmission case was found and the improvementsuggestion was proposed. By comparing the result of before and after improvement wascompared, it shows that the stress value of weak position has reduced about28%-50%after improvement and the strength of automobile transmission case can meet the designrequirements.