Patent ID: 8328297
Filing Date: 2012-12-11
Classification: B60T

Abstract:
1. A brake system comprising: a master cylinder having two first fluid pressure chambers in which brake fluid pressure is generated based on a brake operation of a driver; an electrical fluid pressure generation device comprising: a plurality of wheel cylinders respectively communicating with the two second fluid pressure chambers through respective second fluid passages and generating braking forces for braking vehicle wheels based on fluid pressure generated in the corresponding second fluid pressure chamber; and an anti-lock brake system (ABS) communicating with the respective second fluid passages between the electrical fluid pressure generation device and the plurality of wheel cylinders, the ABS being capable of individually controlling the braking forces generated by the plurality of wheel cylinders, wherein a switch valve is provided in each of the first fluid passages between the master cylinder and the electrical fluid pressure generation device; wherein when the ABS is activated, the switch valves are maintained in a closed state and the electrical fluid pressure generation device is maintained in an operating state; wherein one of said second fluid chambers is disposed on a forward side of each piston such that when the actuator is driven in one direction, the pistons are moved in an advancing direction and brake fluid pressure is generated in each second fluid pressure chamber, wherein when the system is operating normally, and in response to fluid pressure generation in the two first fluid pressure chambers, the actuator operates to drive the pistons in the advancing direction, whereby the first inlet port is obstructed by the first piston, the second inlet port is obstructed by the second piston, and fluid pressure generated in the two second fluid pressure chambers is transmitted to the plurality of wheel cylinders via the first and second outlet ports, wherein when an abnormal operation of the system occurs, and in response to fluid pressure generation in the two first fluid pressure chambers, each of the first piston and second piston are driven in the retreat direction by the respective return spring such that the first inlet port communicates with one of the second fluid pressure chambers, the second inlet port communicates with another one of the second fluid pressure chambers, and fluid pressure generated in the two first fluid pressure chambers is transmitted to the plurality of wheel cylinders via the respective outlet ports, and wherein when regeneration braking is performed, the operation of electrical fluid pressure generation device is stopped such that the pistons are in a retreated position and the inlet ports are open, and the switch valves are closed such that brake fluid pressure of the master cylinder is not transmitted to the wheel cylinders during regeneration braking.