Power Transmission Losses in V-Belt Drives Part 1: Mismatched Belt and Pulley Groove Wedge Angle Effects

Abstract

AV 10 raw-edged V-belts cut to wedge angles from 32° to 42° have been run in 36° grooves on pulleys of 51 mm pitch circle radius. It has been shown experimentally that belts with wedge angles from 37° to 38.5° fitted the grooves best and were the most efficient. The excess speed and torque loss parts of the power loss of other belts was due to the larger radial compliance of these belts which did not fit their pulley groove. Current theoretical models of radial compliance of misfitting belts are shown to be wrong. The results have been generalized and a theory of belt bending distortion developed to give detailed recommendations of the most efficient pulley groove angles in which to run belts cut to 40°, depending on pulley radius, belt construction and belt length.