| Transmission is one of the most important parts of automobile,its performance is directly related to automobile’s performance.Transmission’s vibration and noise has always been one of the most important factors affecting the performance of automobile,although many scholars at home and abroad devoted to the research of this problem,but there is still no general solution to this problem.This paper aimed to deal with the gear whine of the FR automobile by using the method of experimental research and simulation analysis,and studied the TE and meshing effect of the gearset and the structural strength of the transmission case,and finally solved the gear whine in the automobile.The main contents of this paper are as follows:The vibration and noise test under the road environment is carried out on the automobile,and the order tracking method analyzed data showed that gear meshing is the main noise source under 2nd coasting mode.The vibration and noise test under the semi-anechoic chamber of the automobile also showed that there is a gear whine problem under 2nd coasting mode,which excluded the influence of the environmental factors in the automobile road test.The result of the transmission path analysis of the vibration signal showed that the noise of the transmission caused by the gear meshing vibration is mainly transmitted by the transmission case and then through the air path to the cab.The contact pattern test of the gearset showed that the gear meshing effect under 2nd coasting mode is poor.The free modal and constrained modal tests of the transmission case were carried out for analyzing its modal frequencies and mode shapes.The dynamic simulation model of the transmission was established by Romax Designer software,in which the micro parameters of the gear were obtained through the gear precision measurement to ensure the accuracy of the transmission model.The calculated transmission error under 2nd coasting mode was obviously higher than that of other modes,and the contact pattern of the gearset was consistent with the test result,and also the difference between the case mode and the test result is less than 5%,which proved the reliability of the model.The strength checking result of the transmission case showed that the maximum stress of transmission case under 1st gear and reverse gear exceeded the standard value of strength evaluation.By using the single factor analysis method and the orthogonal experimental design method,the influence law of the gearset’s micro parameters on the transmission error was analyzed,and the micro modification scheme of the gearset is made due to the influence law.It determined that the gearset’s micro modification plan can achieve the optimization effect considering the manufacturing tolerance by using tolerance analysis method.The optimization scheme of transmission case was put forward according to the results of modal analysis and case strength analysis.Finally,the validity of the gear modification optimization scheme was proved by experimental verification.In this paper,vehicle test was carried out,and the simulation model of the transmission was established by using Romax Designer software.Finally,the gear modification scheme was formulated in the case of gear machining tolerance,which effectively solved the gear whine problem of the transmission.The above work can provide reference to analyze and research similar problems. |
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