Novel Steel and Aramid/Phenol Composite Gear for a Transmission with Optimum Design and FEM Vibration Analysis

Hybrid gears made of steel and fiber-reinforced polymeric composite material are recently attracting electric vehicle designers' attention due to their possible advantages such as lightweight and lessened transfer of noise and vibration for automotive transmissions. Polymeric composite material may be placed in-between the steel teeth and central hub regions in the radial direction of the gear. The partial usage of polymeric composite material for a gear is expected to reduce the transmissibility of vibration from teeth to hub as well as the weight of the gear-train. Using the finite element method, optimization, vibration and noise analyses have been performed in order to calculate SPL (sound pressure level) for pure steel and hybrid gears, separately. At a specified point of a tooth and a hub, the changes in SPL are computed and are compared to check how effective the polymeric composite region is. The reduction in SPL of the hybrid gear is observed by comparing to that of a pure steel gear. To minimize the weight of the hybrid gear, design optimization is applied by considering fatigue strength of steel and composite material.