Contact Dynamics And Finite Element Analysis Of Operating Mechanism For Automatic Mechanical Transmission

With the high speed development of economy and the increasing of the auto possession,The market's demand for car of assembly automatic transmission is rising. Automatic transmission in automotive applications is growing in popularity. Although traditionally manual transmission in the use of city bus can meet the basic requirements of vehicle dynamic quality and economy,there are shortcomings such as shifting labor-intensive operation,difficulty in controlling the best time to shift,Shift improper operation leading to rough running and influencing riding comfortability. Using conditions of heavy vehicle are very bad,Transmission load is very large,Shifts are too much,and choosing shift control is relatively complex. Starting from the development trend of international heavy vehicle automatic transmission technology,at present our country with manual mechanical transmission in heavy vehicles,and the reality that it has formed a large scale of production capacity,to improve the deft manipulation of heavy vehicles and the safety of the car,improve the dynamic performance and fuel economy of the vehicle,use Automatic Mechanical Transmission (AMT) technology is one of the best ways. Therefore,in these vehicles,research in the shifting structure from manual to automatic control has the extremely vital significance.This paper introduces the design of a complete set of shift actuators for the electric control. The focal point of the design lies in how to perform a required shift action under the conditions of limited space and limited power. According to the actual situation,the way of the combination of worm gear and gear rack meet the relevant requirements. And then pay attention to the combination of the two gear parts and buffering of the two other gears.CAE analysis is the focus of this chapter. Multibody dynamics software RecurDyn is used for multibody dynamics analysis. Through the experiment,force of shift actuator,route and action timehave been measured. Through the force and torque equivalent conversion,the parameters such as force,torque,action travel and action time are added to the dynamic model of actuators for multibody dynamics calculation. Draw contact forces between worm gear and worm and gear rack under dynamic load conditions for the follow-up finite element analysis providing boundary loadsStill spring force of return spring of choosing to block can be drawn for evaluation buffering effect of the spring. Dynamic characteristics can be drawn by the dynamics analysis.Use the grid division software Hypermesh to mesh worm gear and worm and gear rack. Among them,according to the characteristics of the parts,parts can be properly simplified,such as removing the chamfering and parts that have no possibility to contact with,to make finite element analysis quick and efficient.In this paper,Solid187 entity unit is adopted to the worm,Solid185 entity unit is adopted to the gear,etc. Material type is the metal and engineering plastic respectively.Finally,use Ansys software to do finite element analysis and obtain the final results. Import grid model. According to characteristics of contact components such as worm and gear rack,fix one component,add loads gotten from multibody dynamics analysis in the phase of contact with another part,do the finite element analysis of statics,draw contact stress,strain,etc of worm gear and gear rack etc. Analysis of the contact stress between gears provides the basis for the gear design. The purpose of CAE analysis is achieved.