Study of Dynamics Stiffness and Shape Factor of Rubber Mounts to Address High-Frequency Resonance Issue in Electric Powertrain Mounting System

Electric motor mounts resonate at high frequency in the range of 600 to 1000Hz with motor excitation frequency resulting in isolation performance deterioration. There is a selection process of motor mounts such that the force-transfer under transient torque reduced and also avoids high-frequency resonance. The rubber dynamic stiffness plays a significant role in excitation frequency. Rubber shape factor and compound directly contribute towards the dynamic stiffness properties of the mount. Isolation efficiency depends on force transfer to the body and resonance phenomenon. In this paper, the rubber shape of motor mounts, which affect progression characteristics as well as high-frequency resonance, is discussed. The wings-effect of rubber bushes discussed which can be tuned to get the desired frequency shift in order to avoid resonance. Finally, it shows for a given EV (Electric vehicle) powertrain system, a proper selection of mounts along with its internal structure plays a significant role in resonance avoidance which improves the seat rail acceleration as well as addresses force transfer under transient torque.