Matching between Free Angle of Round-Pin Coupler and Carbody Structure Parameters

To explicate the matching relation between main structure parameters of carbody and round-pin coupler, theoretical analysis and dynamic simulation method were used to analyze the relation between main structure parameters of carbody and rotation angle of the coupler in the cases of curve passing and pressure bearing on straight line. Control system simulation method was adopted to establish the model of aligning shoulders taking into account the nonlinear hysteresis characteristics of buffer, which can reflect real-time characteristics of aligning shoulders force. Coupler head profile were discretized to obtain the profile data, which were fitted through the spline interpolating function and reverted to coupler head curve surfaces;then the contact models between curve surfaces of coupler head were established, further considering the interaction between coupler heads, which can accurately simulate the relative movement between coupler heads. Force analysis of carbody at different free angles was conducted, and the equation for designing optimal coupler free angle was presented and validated. The results indicate that actual coupler angles were larger than that of the calculated ones by 0.5~1.0owning to the changes of track curvature. Relative angles between coupler heads can offset that of couplers so as to negotiate curves. To ensure the running safety of locomotive when bearing compressive strength, the coupler free-angle and the carbody structure parameters should match each other, and the design value of the locomotive's coupler free-angle should be less than 8. Overall, the results agree well with the calculated results.