Paper 1: Application of Friction and Wear Results Obtained on a Pin–Disc Machine to the Ring–Traveller Problem

Abstract

An experimental study of the dependence of the coefficient of friction and rate of wear of unlubricated steel surfaces in a pin–disc configuration has suggested the use of certain parameters involving normal force, N, and sliding speed, U, in correlating the effects of surface temperature and surface condition with both friction and wear. The interpretation of these functions in terms of the parameters of the ring–traveller problem suggests that the coefficient of friction can be expressed as a function of U² √(traveller mass/ring radius) and the traveller wear rate is directly proportional to √ (traveller mass/ring radius) providing that sliding conditions are chosen to produce a constant value of surface temperature. This last conclusion is restricted by the previous observation that beyond a certain critical temperature periodic removal of the self-generated surface films occurs. This causes a large increase in the values of both coefficient of friction and wear rate and it is suggested therefore that the ‘temperature instability’ of the surface oxide films may possibly be the prime cause of excessive yarn breakages, and overheated travellers after long periods of operation. An end-breakage criterion is proposed.

Previously published results of the friction and wear measured in ring–traveller mechanisms are re-interpreted in the light of the parameters suggested by the present work.