Dynamics of the differential coupling independently rotating wheels for railway vehicle

In this investigation, the planetary gear differential is intended to the independently rotating wheels as a passive control device of the left and right wheels. Based on dynamics and kinematics analysis of the railway vehicle system and differential system, the differential coupling wheels vehicle (DWV) model and the comparative models, including rigid-wheelset vehicle (RWV) model and the independently rotating wheels vehicle (IRWV) model, are built. Through numerical studies, it can be concluded that the longitudinal creep forces of independently rotating wheels disappear for the separation of the wheels. But in the coupling effect of differential on wheels, the differential coupling wheels vehicle regains longitudinal creep forces and the resetting capability on straight lines. Compared with the rigid-wheelset vehicle, the differential coupling wheels vehicle has superior dynamics, including safety, guiding performance and wear performance on sharp curves. However, due to lack of sufficient longitudinal creep forces, the dynamics of the differential coupling wheels vehicle is slightly worse than that of the rigid-wheelset vehicle on medium radius curves. In general, the differential coupling wheels vehicle solves the problem of guiding and safety of the independently rotating wheels vehicle, and has better dynamic performance than the rigid-wheelset vehicle on sharp curves, which indicates that the differential coupling wheels vehicle is applicable to the urban railway transit which contains many sharp curves.