Accuracy and Wear Resistance of Small Injection-Molded Plastic Gears : For High-Strength and Heat-Resistant Plastics filled with Fiber or Carbon

Abstract

Recently, plastic gears with high strength and heat resistance have become necessary as office equipment becomes compact in size and the operating conditions become more severe. Engineering plastics with base polymers fi1led with glass fiber or carbon have been developed and applied to the gears. The endurance limit or wear resistance of the gears made of these engineering plastics has scarcely been revealed. In this paper, after the features of the errors of these plastic gears were inspected, endurance tests were conducted in order to determine the wear characteristics. It was observed from the results that the glass fiber filled in the plastic gears brought about abrasive wear on mating gear teeth. It was concluded that improvement in the surface durability of a gear pair can be attained by selecting the appropriate number of mating gear teeth such as each aliquot number.