Performance of Thermoplastic Poly-Imide (TPI) Gears at High Temperature : Fatigue Tests of Carbon Fiber Reinforced Gears

Abstract

The present paper describes the fatigue tests of Thermoplastic Poly-Imide (TPI) gears, especially carbon fiber reinforced (CFR) TPI gears, at high temperature. The TPI is one of the super engineering plastics, and has good performance even at high temperature. Futhermore, the CFR-TPI has higher strength ; e.g., its bending strength is 2.4 times higher than that of natural TPI. As a result, the fatigue tests showed that the load capacity of CFR-TPI gears is over 10 times higher than that of natural TPI gears. Natural TPI gears show one of the characteristics of plastic ; i.e., viscoelasticity, so that they have a hysteresis. However, CFR-TPI gears never show such kinds of properties. This means that the CFR-TPI gears have similar characteristics as steel gears.