V-ribbed belt design,wear and traction capacity

Abstract

Laboratory dynamometer experiments have been performed on the running-in of an automotive K-section V-ribbed belt. The rib shape has been found to change, owing to wear, in three regions. At the top of the rib, a shoulder develops; at the root of the rib, debris piles up; in between, the rib wears without change of slope. The main changes occur in the first 20 h of running-in conditions chosen to represent loads found in practice; after running for 250 h, further changes could hardly be observed. The measured rib profiles were input to finite element calculations of the contact pressures between the ribs and the pulley grooves. The purpose was to study the way in which load was shared between the rib flanks and the rib roots and further to study the reduction in traction capacity of the belt due to increased root loading as wear progressed. After running for 250 h, the belt was estimated to have about a 10 per cent lower maximum traction coefficient than when it was new. An improved belt design is suggested, to enable high traction capacity to be maintained for longer times.