The study of a CVT belt using the composite material of carbon fiber-reinforced thermoplastic resin

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