S1103-2-2 Strength of Injection-Molded-Plastic-Gear which Mixed Rice-Hull-Silica-Carbon

Abstract

The injection-molded-plastic-gears are used in such many fields as home electric appliances, information processing equipments, audio-visual equipments, automobiles and so on. Many factors have an effect on load carrying characteristics of an injection-molded-plastic-gear pair. Among others, the materials and the temperature of plastics are the most important factors, because the plastic physical property is greatly different in each plastics type, and the high temperature causes the decrease in Young's modulus of plastic. Therefore, the plastic gears are mixed with the reinforcing materials, which are glass fibers, chemical fibers, polytetrafluoroethylene, and graphite for keeping strength even in high temperature. On the other hand, natural materials are used to focus on the ecological recycling. The rice hull is a residual product of rice and its amount is about 2.6 million tons per year in Japan. Based on the above background, the authors focused on using a rice-hull-silica-carbon (RHSC) with a reinforcing material in plastics. In this study, the strength of the plastic filled RHSC gears was compared with the polyacetal (POM) gears. As a result, the effects of new plastics as gear materials were observed.