Patent ID: 8794716

Claim:
A method of controlling braking force applied to a wheel of a vehicle using a brake fluid pressure control apparatus for a vehicle, the method comprising: providing a fluid pressure passage extending from a fluid pressure source to a wheel brake; providing a pressure regulating valve arranged on the fluid pressure passage, the pressure regulating valve allowing a flow of brake fluid from the fluid pressure source to the wheel brake while restricting a flow of brake fluid from the wheel brake to the fluid pressure source with a valve closing force according to an electric current applied to the valve, where an opening degree of the pressure regulating valve varies in a continuous range according to the valve closing force that is controlled based on an amount of the electric current applied to the valve; providing a pump for feeding pressurized brake fluid to the fluid pressure passage between the pressure regulating valve and the wheel brake; providing a motor for driving the pump; and providing a controller which controls the electric current applied to the pressure regulating valve in accordance with a target fluid pressure for the wheel brake to control fluid pressure supplied to the wheel brake, wherein the controller determines a first electric current value of the electric current applied to the pressure regulating valve in accordance with a target fluid pressure for the wheel brake; converts the target fluid pressure into fluid volume and calculates a required flow rate based on this fluid volume; calculates a required rotation speed of the motor based on the required flow rate and on the basis of an efficiency (the pump's flow rate corresponding to the motor rotation speed) of the pump; and increasing the first electric current applied to the pressure regulating valve to a predetermined electric current value to obtain a second electric current when the required rotation speed exceeds an actual rotation speed of the motor obtained through detection or estimation, wherein a first electric current corresponding to the first electric current value is applied to the pressure regulating valve when the required rotation speed is not greater than the actual rotation speed of the motor, and a second electric current corresponding to the second electric current value is applied to the pressure regulating valve when the required rotation speed is greater than the actual rotation speed of the motor.