Modeling and characteristic study of the shifting engagement process in stepped transmission

Considering the problems of long power interruption and large impact forces in engagement between the synchronizer sleeve and the gear ring, this study investigates the effects of the shift control parameters of a stepped transmission on shift quality. First, an accurate dynamic model of the engagement procedure is established by introducing a Poisson recovery coefficient collision model to analyze the impact of sleeves and gear rings. Then, MATLAB/Simulink is used to establish a gear shifting simulation model, through which the influence of gear shifting force, relative speed difference, and relative rotation angle on the gear shifting impact are analyzed. Simulation results show when the relative angle and speed difference are certain, impact increases as shifting force rises; when shifting force and speed difference are fixed, impact climbs as the absolute value of the relative angle grows. Meanwhile, compared with impact produced when the gear-ring speed is low (under fixed shifting force and speed difference), more impact is generated when the gear-ring speed is higher than the sleeve speed. This provides a basis for establishing a shifting control strategy. © 2020 Elsevier Ltd