A study for development of plastic worm gears. 2nd report, Plastic worm gear filled with mica filler.

Abstract

In use, worm gears, the teeth of which are slid a relatively long distance, generate a large quantity of heat. It is impossible for plastics, which are inferior in heat resistance, to be applied for such worm gears for use in the transmission of high power without lubricants. The first report suggests that composite plastics filled with carbon fibers, solid lubricants, etc. are suitable as materials for worm gears. However, the worm gears made of the composite plastics are expensive. In this study, inexpensive plastics of nylon filled with mica fillers have been developed, and their application to worm gears has been examined. Increasing amounts of the mica filler cause the heat resistance temperature to become higher. However, they reduce the bonding degree of the nylon to the mica attained in the polymerization. Accordingly, when the composite plastics of nylon are used for the sliding parts, the wear resistance may be insufficient. The wear resistance, coefficient of friction, surface roughness, surface temperature, and worm gears of the nylon composite plastics with various amounts of mica filler have been examined to determine the optimum amount of the mica filler.