Studies on the Wear and Failure of Plastic Gears : 4th Report, On the Fatigue of Plastic Materials used for Gears

Abstract

This paper describes rotary bending fatigue tests for plastic materials used for gears . The fatigue limits of plastics were measured and the fatigue fracture 5urfaces were observed using an electron microscope. In addition, the wear and failure of plastics were measured for number of revolutions of plastic gears, and the fatigue fracture surfaces of gear teeth were also observed. The results of fatigue test have something in common with those of the wear and failure of gears Two kinds of fatigue were demonstrated by the tests: one being thermal fatigue: and the other being fatigue due to the development of microscopic cracks, because the temperature of the test pieces were measured and the measured values were compared with the calculated values; both showing a rather good coincidence. The results provide data on the design and used of plastic gears.,