Research on A Spatial Compliant Mechanism for the Power Release Branch in Vehicle Side Door Latch

A spatial compliant mechanism with variable degree of freedom (DOF) is proposed for the Power Release branch of automobile side door latch. The mechanism has a compliant RSSPR motion mode with 2-DOF and a RSSR motion mode with 1-DOF. Due to that the compliant mechanism has the advantages of various motion modes and force adaptive flexibility, the compliant mechanism is applied to the vehicle side door latch as a power release branch, which meets all the requirements of the door latch operation function. In order to study the motion stability of compliant mechanism, a characteristic point of compliant mechanism is selected and its motion trajectory and phase diagram are obtained by the Adams simulation. The coincidence extent of the starting and ending points are taken as the evaluation index of the motion stability of compliant mechanism. Through the research, it is found that the two-point coincidence errors of the mechanism are controlled within 0.006mm, which meet the basic requirements of the motion stability of car door latch. This paper provides a way to analyze the stability of practical complex mechanical system by trajectory and phase diagram.