초록 ▼

A vehicle brake device A is provided with a master cylinder 10 for generating a fluid pressure depending on the stepping state of a brake pedal 11 and a differential pressure control valve 43 constituted by a solenoid valve of the type that has two ports 43a, 43b and is capable of controlling the di

A vehicle brake device A is provided with a master cylinder 10 for generating a fluid pressure depending on the stepping state of a brake pedal 11 and a differential pressure control valve 43 constituted by a solenoid valve of the type that has two ports 43a, 43b and is capable of controlling the differential pressure between the both ports 43a and 43b. The differential pressure control valve 43 is connected at its port 43a to an outlet port 10a of the master cylinder 10. An ECU 70 controls the differential pressure control valve 43 to generate a controlled differential pressure corresponding to the pedal operation state of the brake pedal 11 between the both ports 43a and 43b. Thus, according to the vehicle brake device A, it can be realized to obtain a pedal feeling which is smooth without suffering any delay in response, to easily alter a reaction force property of the brake pedal for any of various vehicle models, and to decrease in cost as well as dimension.

대표청구항 ▼

What is claimed is: 1. A vehicle brake device comprising: a master cylinder for generating a fluid pressure depending on the stepping state of a brake pedal; a pedal stroke sensor for detecting a pedal stroke of the brake pedal; a differential pressure control valve constituted by a solenoid valve

What is claimed is: 1. A vehicle brake device comprising: a master cylinder for generating a fluid pressure depending on the stepping state of a brake pedal; a pedal stroke sensor for detecting a pedal stroke of the brake pedal; a differential pressure control valve constituted by a solenoid valve including two ports and configured to vary the differential pressure between the two ports, when the brake pedal is depressed, in dependence on the pedal stroke detected by the pedal stroke sensor, and connected at one of the two ports thereof directly to an outlet port of the master cylinder; control means for controlling the energization of the differential pressure control valve to generate a controlled differential pressure between the two ports of the differential pressure control valve, the control means including controlled differential pressure deriving means for deriving the controlled differential pressure corresponding to the pedal stroke detected by the pedal stroke sensor; a stroke simulator connected directly to the other port of the differential pressure control valve for absorbing the pressurized fluid supplied from the outlet port of the master cylinder through the differential pressure control valve; and a one-way valve arranged in parallel relation with the differential pressure control valve for permitting the flow only from the stroke simulator to the master cylinder; wherein the controlled differential pressure deriving means is configured to derive the controlled differential pressure from an operation expression or a map representing the correlation between the pedal stroke detected by the pedal operation state detection means and the controlled differential pressure; and wherein the control means further includes: applied current deriving means for deriving an applied current value corresponding to the controlled differential pressure derived by the control differential pressure deriving means, from an operation expression or a map representing the correlation between the controlled differential pressure and the applied current value to the differential pressure control valve; and differential pressure control valve control means for controlling the differential pressure control valve based on the applied current value derived by the applied current deriving means. 2. A vehicle brake device comprising: a master cylinder for generating a fluid pressure depending on the stepping state of a brake pedal; a differential pressure control valve constituted by a solenoid valve including two ports and configured to control the differential pressure between the two ports, and connected at one of the two ports thereof directly to an outlet port of the master cylinder; control means for controlling the energization of the differential pressure control valve to generate a controlled differential pressure corresponding to the pedal operation state of the brake pedal between the two ports of the differential pressure control valve; pedal operation state detection means for detecting a pedal stroke of the brake pedal as the pedal operation state; controlled differential pressure deriving means for deriving a controlled differential pressure corresponding to the pedal stroke detected by the pedal operation state detection means, from an operation expression or a map representing the correlation between the pedal stroke detected by the pedal operation state detection means and the controlled differential pressure; applied current deriving means for deriving an applied current value corresponding to the controlled differential pressure derived by the control differential pressure deriving means, from an operation expression or a map representing the correlation between the controlled differential pressure and the applied current value to the differential pressure control valve; differential pressure control valve control means for controlling the differential pressure control valve based on the applied current value derived by the applied current deriving means; a stroke simulator having an inlet port to be supplied with pressurized fluid from the master cylinder for absorbing the pressurized fluid supplied from the outlet port of the master cylinder through the differential pressure control valve, the inlet port of the stroke simulator connected directly to the other port of the differential pressure control valve; and a one-way valve arranged in parallel relation with the differential pressure control valve for permitting the flow only from the stroke simulator to the master cylinder. 3. The vehicle brake device as set forth in claim 1, further comprising: a reservoir tank for storing the fluid returned from a brake wheel cylinder which restrains the rotation of a vehicle wheel. 4. The vehicle brake device as set forth in claim 1, wherein the differential pressure control valve is a solenoid valve which generates a differential pressure proportional to an electromagnetic force. 5. A vehicle brake device comprising: a master cylinder for generating a fluid pressure depending on the stepping state of a brake pedal; a pedal stroke sensor for detecting a pedal stroke of the brake pedal; a differential pressure control valve constituted by a solenoid valve including two ports and configured to vary the differential pressure between the two ports, when the brake pedal is depressed, in dependence on the pedal stroke detected by the pedal stroke sensor, and connected at one of the two ports thereof directly to an outlet port of the master cylinder; control means for controlling the energization of the differential pressure control valve to generate a controlled differential pressure between the two ports of the differential pressure control valve, the control means including controlled differential pressure deriving means for deriving a controlled differential pressure corresponding to the pedal stroke detected by the pedal stroke sensor; a stroke simulator connected directly to the other port of the differential pressure control valve for absorbing the pressurized fluid supplied from the outlet port of the master cylinder through the differential pressure control valve; a one-way valve arranged in parallel relation with the differential pressure control valve for permitting the flow only from the stroke simulator to the master cylinder; wherein the differential pressure control valve, when energized, communicates the two ports with each other through an opening degree that generates the controlled differential pressure derived by the controlled differential pressure deriving means between the two ports, to permit the flow of the pressurized fluid from the one port to the other of the two ports, and upon the stepping of the brake pedal, the outflow of the pressurized fluid from the outlet port of the master cylinder is permitted to give the brake pedal a reaction force and a stroke; wherein the controlled differential pressure deriving means is configured to derive the controlled differential pressure from an operation expression or a map representing the correlation between the pedal stroke detected by the pedal stroke sensor and the controlled differential pressure; and wherein the control means further includes: applied current deriving means for deriving an applied current value corresponding to the controlled differential pressure derived by the control differential pressure deriving means, from an operation expression or a map representing the correlation between the controlled differential pressure and the applied current value to the differential pressure control valve; and differential pressure control valve control means for controlling the differential pressure control valve based on the applied current value derived by the applied current deriving means. 6. The vehicle brake device as set forth in claim 5, further comprising: a reservoir tank for storing the fluid returned from a brake wheel cylinder which restrains the rotation of a vehicle wheel. 7. The vehicle brake device as set forth in claim 5, wherein the differential pressure control valve is a solenoid valve configured to generate a differential pressure proportional to an electromagnetic force. 8. A vehicle brake device comprising: a master cylinder for generating a fluid pressure depending on the stepping state of a brake pedal; a pedal stroke sensor for detecting a pedal stroke of the brake pedal; a differential pressure control valve constituted by a solenoid valve including two ports and configured to vary the differential pressure between the two ports, when the brake pedal is depressed, in dependence on the pedal stroke detected by the pedal stroke sensor, and connected at one of the two ports thereof directly to an outlet port of the master cylinder; control means for controlling the energization of the differential pressure control valve to generate a controlled differential pressure between the two ports of the differential pressure control valve, the control means including controlled differential pressure deriving means for deriving the controlled differential pressure corresponding to the pedal stroke detected by the pedal stroke sensor; a stroke simulator connected directly to the other port of the differential pressure control valve for absorbing the pressurized fluid supplied from the outlet port of the master cylinder through the differential pressure control valve; and a one-way valve arranged in parallel relation with the differential pressure control valve for permitting the flow only from the stroke simulator to the master cylinder; and wherein the differential pressure control valve is operable to generate the controlled differential pressure which increases in direct proportion to the value of electric current applied to the differential pressure control valve when the electric current is greater than a predetermined value. 9. The vehicle brake device as set forth in claim 8, wherein the controlled differential pressure is a differential pressure which is generated to be added to a base property being a pedal stroke to pedal stepping force property attributed to a mechanical construction which the vehicle actually has, so as to follow a target property which is a pedal stroke to pedal stepping force property set as a target in the vehicle. 10. The vehicle brake device as set forth in claim 9, wherein a plurality of target properties are provided to be selectable by the driver.