Vehicle brake device

#The present invention relates to a vehicle brake device in which a braking force imparted to a vehicle is controlled in accordance with a brake pedal operation amount by a driver.

#As an example of a vehicle brake device in which a braking force imparted to a vehicle is controlled in accordance with a brake pedal operation amount by a driver, vehicle brake devices disclosed, for example, in JP-A-2010-167915 (Patent Literature 1) and JP-A-9-328069 (Patent Literature 2) are known. In these vehicle brake devices, a braking force based on a controlled hydraulic pressure generated by an accumulator and an electromagnetic valve is imparted to wheel cylinders in response to the movement of an input piston.

#However, when a power supply system fails, no electric power is supplied to the electromagnetic valve, and the servo pressure cannot be controlled. Namely, it is not possible to increase the servo pressure according to the operation amount of the brake pedal by electrically controlling the pressure. When this occurs, the braking force cannot be exhibited when the power supply fails.

#FIG. 1 is a block diagram depicting the configuration of a vehicle brake device of a first embodiment;

#FIG. 2 is a block diagram depicting the configuration, partially sectional, of a regulator of the first embodiment;

#FIG. 3 is a block diagram depicting the configuration of a vehicle brake device of a second embodiment;

#Hereinafter, embodiments of the invention will be described by reference to the drawings. It should be noted that the drawings are conceptual drawings, which do not specify dimensions of detailed constructions.

#FIG. 1 shows a schematic block diagram of a vehicle brake device according to a first embodiment of the invention. A vehicle brake device of this embodiment includes a master cylinder 1 having master pistons 113, 114 that are disposed in a direction in which an input piston 112 moves forwards with a spacing distance B defined between themselves and the input piston 112 and which slide in an axial direction independently of the input piston, a reaction force generating unit 2 which generates a reaction pressure according to a traveling amount of the input piston 112 in a reaction force chamber 128, a directional control valve 3 which is provided on an open line 31 that is caused to branch off from a fluid line 130 which establishes a communication between the reaction force chamber 128 and the reaction force generating unit 2 and which communicates with a reservoir 32, a brake booster 4 which generates a servo pressure, wheel brakes 5 for wheels 5FR, 5FL, 5RR, 5RL which have wheel cylinders 541 to 544 communicating with master chambers 132, 136 of the master cylinder 1, a brake ECU 6 which controls the directional control valve 3 and the brake booster 4, various sensors 71 to 74 and a hybrid ECU 8 which controls a regenerative braking force. Hereinafter, constituent elements provided in the vehicle brake device of this embodiment will be described in detail. The hybrid ECU 8 is known, and hence, the description thereof will be omitted here. Additionally, the sensors 71 to 74 are configured so as to communicate with the brake ECU 6. The brake ECU6 controls mainly various electromagnetic valves 3, 41, 42 and a motor 433.

#(Master Cylinder 1 and Reaction Force Generating Unit 2)