Non contact wear measurement on pneumatic seals
Abstract An experimental methodology aimed at the evaluation of wear in pneumatic seals is presented. New equipment was designed and manufactured in order to measure the radial thickness of worn material on the sealing edge both axially and circumferentially, by means of a laser sensor, as well as to avoid the necessity of disassembling the seals. The methodology is intended as an instrument for a quick comparison of seal prototypes and is proposed as an alternative to those methods that globally quantify the wear of samples by measuring their loss of weight or volume. Results obtained on a NBR commercial lip seal are presented.
Friction, wear and surface damage mechanisms of pneumatic clutch actuators
Abstract Wear and surface degradation mechanisms of a pneumatic clutch actuator have been studied. The applied test method simulates the sliding contact of an anodised aluminium surface against a rubber lip seal and a PTFE guiding ring. The influences of contact load, temperature and particle contamination on wear mechanisms and friction were investigated. A controlled amount of lubrication was applied; both pure silicone grease and silicone grease mixed with standard dust particles were used. The wear occurring at the tests with only silicone grease is similar, but on a lower scale, to the wear at the tests with a mixture of silicone grease and standard dust. The polishing of the anodised aluminium is increased with increasing temperature or increasing load. The wear of the anodised aluminium surface is more prominent when sliding against the PTFE guiding ring than when sliding against the lip seal. The wear of the guiding ring increases with increasing load or increasing temperature. The lip seal is worn but at 140 °C (with silicone grease or with a mixture of silicone grease and standard dust) or at increased load (with a mixture of silicone grease and standard dust) a thick layer of adhered material is formed.
State-of-the-art of polymer tribology
Along with the extensive application of polymers for tribological purposes, the understanding of polymer tribology is becoming increasingly important. A broad overview of the general area of polymer tribology is presented in this paper. The progress in understanding the field over the past decade is reviewed under the three topics of rubber tribology, plastic tribology and tribology of polymer composites. It is hoped that this paper will serve as a valuable source of reference for future tribologists.