Vehicle brake device

#This invention relates to a vehicle brake device which permits regenerative cooperative control, and particularly to a reliable and inexpensive vehicle brake device.

#U.S. patent publication Ser. No. 2002/0140283A1 discloses a vehicle brake device which can perform regenerative cooperative control. One of the brake devices disclosed in this patent publication is shown in FIG. 4.

#This brake device 10 includes a brake pedal 11, a hydraulic pressure generating device 12 for producing a predetermined hydraulic pressure by means of a power-driven pump, an electric control device 13 for controlling the brake device, a reservoir 14, a cylinder 15, a pressure adjusting valve 16, hydraulic passages 17, 20, 21, a master cylinder 18, an auxiliary hydraulic chamber 19 that receives the output hydraulic pressure of the pressure-adjusting valve 16, wheel cylinders 22–25 for imparting braking force to the vehicle wheels, electromagnetic proportional valves 26 and 27, pressure sensors 28 and 29, solenoid valves 28 and 29, and check valves 32 and 33.

#Other features and objects of the present invention will become apparent from the following description made with reference to the accompanying drawings, in which:

#FIG. 1 is a sectional view showing a schematic structure of an embodiment of the brake device according to this invention;

#FIG. 2 is a graph showing the relation between the brake operating force and the vehicle deceleration during regenerative cooperative control;

#FIG. 1 shows the embodiment of this invention. This vehicle brake device 50 comprises a hydraulic pressure generating device 12 including an accumulator 12a, a pressure sensor 12b and a pump 12d driven by an electric motor 12c, an electrical control device 13 for controlling the brake device, a reservoir 14 storing brake fluid, a pressure adjusting device 40 including a pressure adjusting valve 16, a master cylinder 18, an auxiliary hydraulic chamber 19 for receiving the output hydraulic pressure of the pressure adjusting valve 16, wheel cylinders 22–25 for imparting braking force to vehicle wheels, electromagnetic proportional valves 26, 27, and pressure sensors 28, 29.

#The hydraulic pressure generating device 12 generates a predetermined hydraulic pressure P1 by means of a pump 12d, stores it in the accumulator 12a, controls the electric motor 12c based on detection signals of the pressure sensor 12b to keep the hydraulic pressure P1 between predetermined upper and lower limit values, and supplies the hydraulic pressure P1 to the pressure adjusting valve 16.

#The pressure adjusting device 40 includes the pressure adjusting valve 16 which adjusts hydraulic pressure supplied from the hydraulic pressure generating device 12 to a value corresponding to the operating force applied to the brake pedal 11 and outputs it. It further includes an auxiliary piston 41 mounted in a cylinder 15 with its tip facing the auxiliary hydraulic chamber 19, a simulator piston 42b provided in the auxiliary piston 41 with its front surface facing a simulator chamber 42a, an elastic member 42c for imparting a stroke corresponding to the brake operating force applied to the brake pedal 11 to the simulator piston 42b, and a distributing device 43 for distributing the brake operating force transmitted from the simulator piston 42b through the elastic member 42c and transmitting to the pressure adjusting valve 16 and auxiliary piston 41.