Effects of tribological and material properties of wire rope on the motion synchronization of a precision flexible transmission device

Abstract

During the long-term service process of a precision flexible transmission device driven by a wire rope, the tribological and material properties of the rope changes and causes a motion synchronization degradation. In this paper, a finite element model and a transmission error model of the device are built with the considerations of the surface wear of the rope, the variations in the rope-pulley friction coefficient, elastic modulus and Poisson’s ratio of the rope material. The evolutions of transmission error, elongation, stress state, and the output torque of the device as well as the tension distribution along the rope are solved. The results show that the motion synchronization degradation results from the surface wear, the decrements in the friction coefficient and elastic modulus, and the increment in the Poisson’s ratio. The rope tension decreases in the wrapping section around the guide pulley, and increases in most other positions due to wear. An increment in the friction coefficient causes reduced tensions in the wrapping section around the active pulley and the free section between guide pulleys, and worsens the tension uniformity and output torque performance of the device. The maximum stress of the rope increases with increasing elastic modulus and decreasing Poisson’s ratio.