Experimental estimation of efficiency and kinematic accuracy of a spherical roller transmission

Abstract

Abstract Spherical roller transmissions with double-row pinions provide high reduction ratios in drives with a compact and lightweight design. The transmissions can be used as mechanical modules in kinematic chains of robots and manipulators. The pinion has two rows of coaxially arranged rollers and, when in operation, performs a regular precession. The paper examines the characteristics of an experimental model of a speed reducer with a spherical roller transmission with a reduction ratio of 44. The arrangement of the test rig as well as the test instruments and methods are described. The results of experimental study determining the efficiency of a spherical roller transmission depending on the torque being transmitted and the rotational speed of the drive shaft are presented. It has been found that the mean efficiency of the speed reducer is within the range of 0.7 … 0.8 and its maximum value is 0.81, which corresponds to the efficiency of worm gears with similar characteristics. The theoretical calculations for determining the efficiency, which were obtained in previous studies, have been confirmed; the value of the reduced friction coefficient has been calculated. The constancy of the efficiency and the reduction ratio of the experimental model of the speed reducer and the factors influencing this constancy have been investigated.