Simulation Analysis Oil The Shifting Performance Of Mechanical Transmission Based On Virtual Prototype Technology

Mechanical transmission’s shifting performance is related to the performance ofvehicle directly and the shift control mechanism must have controlling quality of reliabilityand portability as it is a vector of human-machine-interaction. At present, lots of mechanicaltransmissions cannot meet the requirements of consumers in the domestic market for theirbad shifting performance. Therefore, all automotive manufacturers are positively seekingreasonable subjective and objective shifting performance evaluation methods and evaluationindexes, so as to improve performance of their products and design more excellent products.But, there is lack of effective simulation method to evaluate the transmission’s shiftingperformance which is generally obtained by the test method. So far the research of shiftingperformance simulation evaluation by analyzing the shifting process of mechanicaltransmission shifting system dynamic models is still in an early stage.Virtual Prototype Technology can be used to establish digital simulation model ofphysical prototype and finish the performance test and evaluation on the computer based onCAD technology. Dynamic models of shifting process for mechanical transmission werebuilt by using Pro/E and ADAMS based on Virtual Prototype Technology and Germany GIFtransmission test method. Since the shift force is the driver’s reaction to the mechanicaltransmission and drivetrain during the shift process, dynamic models include the clutch disc,mechanical transmission and shift control mechanism, etc. The dynamic model of shiftflexible shaft was established by using simplified modeling method of bushing-rigidcylinder connecting. The integrated dynamic model for twin-cone-lock-ring synchronizerwas established by using both the joints and contact restrains and the model can simulatethe synchronizing and locking process of synchronizing ring.The relationships between the shift force and the shift travel were established bysimulating shifting process of1-2upshift,2-1downshif, N-1and N-R in ADAMS. Thequestion whether the shift feeling is diminished by hard shifting can be found by analyzingthe shift force, which provides reference for mechanical transmission design. Theexperimental results agree well with the model，which shows that this dynamic simulationstudy of mechanical transmission is valid. Finally, the influences of the synchronizing ring friction coefficients, the stiffness and damping of flexible shaft, the shifting speed on thedynamic simulation were presented.This paper provides effective simulation evaluation methods and evaluation indexes toevaluate the shifting performance of mechanical transmission objectively. Therefore, theshifting performance can be predicted and evaluated completely through simulation analysismethod in the initial mechanical transmission design stage, which improve productperformance and design efficiency significantly.