the present invention relates to a limit - torque coupling mechanism with delay restoring function . when the relative coupling portion is forced by torque to reverse the limit - torque coupling mechanism , a delay in the restoring function to reduce noise and frictional loss arising from subsequent relative sliding is accomplished so as to restore coupling during the decrease in torque difference or speed difference . to accomplish the aforesaid function lie in that , the design of the torque coupling mechanism being forcibly reversed includes a return motion damper to produce mechanical friction damping , fluid damping or magnetic damping .