Analytic approaches for keeping high braking efficiency and clamping efficiency of electro wedge brakes

The transfer from engine drive vehicles to electric vehicle has been proceeding due to fuel exhaustion, higher fuel costs, and environmental restrictions. This trend has also led to a transition in brake system from the hydraulic brake system to the electric brake system, which uses electric power. This electric brake system has led to an enhancement of safety and eco-friendliness due to a reduction braking distance, a rapid-response property, and the elimination of braking oil. However, one of the big problems to solve for practical usages is the need of a high power motor to enable braking forces as strong as those of hydraulic brake systems. Therefore, it is necessary to develop high efficiency electro mechanical brakes with a proper reinforcement mechanism to solve this problem. In this paper, we describe a wedge structure that has a self-reinforcing effect; we propose a proper actuating direction for a movable wedge to obtain greater clamping efficiency and braking efficiency, which will mean a better relation of the motor force as the input to the braking force as the output. Further, we propose the method to keep the most braking efficiency and clamping efficiency without reference to the variations of frictional coefficient.