Study of a continuously variable transmission belt made of carbon fiber-reinforced thermoplastic resin

Abstract

The purpose of this study is to develop automotive frictional parts, especially continuously variable transmission (CVT) blocks using a composite material made of thermoplastic resin and fiber. CVT blocks were used at about 100ºC under high pressure and friction conditions; nylon 9T, otherwise named PA9T, was used. PA9T has a high melting point which is higher than the maximum temperature at the state of slip. To apply composite materials to the manufacture of CVT blocks, material properties such as high strength, modulus of elasticity and fatigue strength are important. Therefore, the aim of this study is improvements in mechanical properties by adding fillers to PA9T under various compounding and molding conditions. PA9T and carbon fibers were mixed using a twin screw extruder. After compounding, dumbbell specimens were made using an injection molding machine. Bending, fatigue and abrasion tests were conducted. Moreover, the transmission capacity of CVT belt made of PA9T composites was evaluated and slip tests were conducted. According to the results of tests, PA9T with CF38.8 vol% achieved desired values for CVT application. The CVT belt has a torque capacity of 40 Nm under an axle load of 2.0 kN.