Abstract: Output shaft coordinate system of the trigeminal sliding universal joint mechanism installed twin radial bearings is established, and the relationship equations of input shaft and output shaft are established by using coordinate transformation method, to derive the motion equations of output shaft when the movement of input and output shaft existing deflection angle. The relative motive versus of the first slider along the trigeminal arm and the guide groove are obtained by the numerical analysis. The simulation model is imported into ADAMS to compare with the theoretical analysis. The results show that the mechanism has a characteristic of constant velocity transmission and the output movement trajectory is a cylindrical which its radius angle only relevant with the input deflection angle and the distance between the slot-oriented center line and the input shaft axis. The relative displacement, relative velocity and relative acceleration curves of the first slider along the trigeminal arm are similar to a sine curve and do reciprocating motion for two multiple to the input shaft in a rotation period. The reciprocating of the slider along the guide groove is the same frequency with the input shaft, and the relative displacement, relative velocity curves are similar to a sine curve but the relative acceleration curve deviates significantly from the standard sine curve. The motion simulation shows the correctness of the mathematical model and numerical analysis in theory.

Key words: constant velocity transmission, kinematic analysis, trigeminal sliding universal joint mechanism, twin radial bearings