Patent ID: 8046149

Claim:
A brake apparatus for a vehicle, comprising: a master cylinder for generating hydraulic pressure according to a brake operation force applied by an operator of said vehicle; a main pipe; a brake caliper which is operatively connected with the master cylinder via said main pipe; a fluid loss simulator which is operatively connected to an end section portion of a first branch pipe branched from the main pipe; a first solenoid valve which is normally closed, and which is disposed in a middle portion of the first branch pipe; said first solenoid valve being operable to selectively connect or disconnect the master cylinder with the fluid loss simulator; a hydraulic modulator which is connected to an end portion of a second branch pipe branched from the main pipe on a brake caliper side with respect to the first branch pipe; said hydraulic modulator being operable to apply hydraulic pressure, generated by a driving force of an actuator, to the brake caliper; a second solenoid valve which is normally closed, and which is disposed in a middle portion of the second branch pipe; said second solenoid valve being operable to selectively connect or disconnect the hydraulic modulator with the brake caliper; a third solenoid valve which is normally open, and which is disposed in a middle portion of the main pipe; said third solenoid valve being operable to selectively connect or disconnect the master cylinder with the brake caliper; a first pressure sensor disposed on the main pipe between the master cylinder and the third solenoid valve; a second pressure sensor disposed on the first branch pipe between the first solenoid valve and the fluid loss simulator; a third pressure sensor disposed on the second branch pipe between the second solenoid valve and the hydraulic modulator; and a control unit for detecting output values of the first, second, and third pressure sensors; wherein a resolution of the second pressure sensor is set a higher value than resolutions of the first and third pressure sensors; wherein the control unit is operable to energize and thereby open the first solenoid valve, and to detect the output value from the second pressure sensor; and wherein when the output value of the second pressure sensor is less than a predetermined value, the control unit executes a zero-point correction by storing respective detected output values from the first, second, and third pressure sensors as zero points for the first, second and third pressure sensors, respectively.