초록 ▼

First hydraulic-pressure supply piping extended from an accumulator is connected to a first supply port (that is, to a second pressure chamber) of a cylinder, and to second hydraulic-pressure delivery piping of an ABS via third hydraulic-pressure supply piping having a third linear valve. When the b

First hydraulic-pressure supply piping extended from an accumulator is connected to a first supply port (that is, to a second pressure chamber) of a cylinder, and to second hydraulic-pressure delivery piping of an ABS via third hydraulic-pressure supply piping having a third linear valve. When the braking hydraulic pressure Pf is reduced in the ABS, the degree and the period of time that the third linear valve is opened are set according to the amount of fluid discharged from the second hydraulic-pressure delivery piping to a reservoir tank through a pressure-reducing valve so that a certain amount of fluid is returned from the first hydraulic-pressure supply piping to the second hydraulic-pressure delivery piping via the third hydraulic-pressure supply piping.

대표청구항 ▼

1. A vehicular brake system comprising: a cylinder;an input piston supported freely movably in an axis direction in the cylinder;an operation part connected to the input piston;a pressurizing piston disposed coaxially with the input piston and supported freely movably in an axis direction in the cyl

1. A vehicular brake system comprising: a cylinder;an input piston supported freely movably in an axis direction in the cylinder;an operation part connected to the input piston;a pressurizing piston disposed coaxially with the input piston and supported freely movably in an axis direction in the cylinder, wherein the pressurizing piston is configured to be pushed by the input piston when a malfunction occurs;a control-hydraulic-pressure setting unit that sets a control hydraulic pressure that corresponds to an operation force applied to the input piston through the operation part;a hydraulic-pressure supply device that generates braking hydraulic pressure by supplying the control hydraulic pressure set by the control-hydraulic-pressure setting unit to the pressurizing piston;a pressure regulating device configured to regulate a braking hydraulic pressure for each of wheels individually, wherein the braking hydraulic pressure is generated by the hydraulic-pressure supply device;a hydraulic pressure source connected to the hydraulic-pressure supply device and the pressure regulating device; andan operation-force absorbing mechanism that absorbs the operation force applied to the input piston through the operation part, whereinthe hydraulic-pressure supply device supplies the control hydraulic pressure to a first pressure chamber disposed on one side of the input piston with respect to a moving direction thereof, or to a second pressure chamber disposed on the other side of the input piston,the hydraulic pressure source is configured to supply hydraulic fluid to the first pressure chamber or the second pressure chamber and to the pressure regulating device, and part of a supply line from the hydraulic pressure source to the first pressure chamber or the second pressure chamber and part of a supply line from the hydraulic pressure source to the pressure regulating device are common, andthe operation-force absorbing mechanism includes a communication passage provided to the input piston that is configured to supply and discharge hydraulic fluid between the first pressure chamber and the second pressure chamber when open, so that a pushing force of the input piston is not transmitted to the pressurizing piston when the communication passage is open. 2. The vehicular brake system according to claim 1, wherein the pressure regulating device includes: a pressure-sustaining valve and a pressure-reducing valve for each wheel; and a flow control valve provided between the hydraulic pressure source and the pressure regulating device, anda degree and a period of time that the flow control valve is opened are set according to an amount of fluid discharged through the pressure-reducing valve. 3. The vehicular brake system according to claim 2, wherein the pressure regulating device sets the degree of opening of the flow control valve based on the amount of fluid to be discharged, and a pressure difference between a hydraulic pressure supplied by the hydraulic pressure source and the braking hydraulic pressure generated by the hydraulic-pressure supply device. 4. The vehicular brake system according to claim 2, wherein the pressure regulating device sets an amount of returned fluid that is more than the amount of fluid discharged through the pressure-reducing valve, and sets the degree and the period of time that the flow control valve is opened, according to the amount of returned fluid. 5. The vehicular brake system according to claim 2, wherein the pressure regulating device determines whether bottoming of the pressurizing piston is occurring by comparing the control hydraulic pressure and the braking hydraulic pressure, and, if it is determined that the bottoming is occurring, sets the degree of opening of the flow control valve at a predetermined, desired degree of opening. 6. The vehicular brake system according to claim 5, wherein the desired degree of opening of the flow control valve corresponds to a desired value of the braking hydraulic pressure on the pressurizing piston side, and is set lower than a degree corresponding to a desired value of the control hydraulic pressure on the input piston side. 7. The vehicular brake system according to claim 2, wherein the pressure regulating device has an initial position detection device that detects whether the pressurizing piston is placed at an initial position, and,when the initial position detection device detects that the pressurizing piston has returned to the initial position, the pressure regulating device closes the flow control valve. 8. The vehicular brake system according to claim 2, wherein the pressure regulating device closes the flow control valve when the braking hydraulic pressure drops. 9. The vehicular brake system according to claim 2, wherein, when a rate of change of the control hydraulic pressure exceeds a predetermined value, the pressure regulating device opens the flow control valve. 10. The vehicular brake system according to claim 1, further comprising a regulator that is housed in the pressurizing piston. 11. The vehicular brake system according to claim 10, wherein the communication passage, on a first end of the input piston that is adjacent to the first pressure chamber, includes a portion with decreasing diameters toward a second end of the input piston that is adjacent to the second pressure chamber. 12. The vehicular brake system according to claim 11, wherein the regulator includes a load transmitter that is movable, a tip portion of the load transmitter that extends through the pressurizing piston being contactable with the input piston at the portion of decreasing diameters to close the communication passage. 13. The vehicular brake system according to claim 12, wherein the regulator includes a poppet valve, the poppet valve being movable with contact from an end of the load transmitter that is opposite the tip portion. 14. The vehicular brake system according to claim 13, wherein a space between the cylinder and the pressurizing piston forms a third pressure chamber, a space adjacent to the input piston forms a fourth pressure chamber that is between the first and second pressure chambers, and a space between the load transmitter and the poppet valve forms a fifth pressure chamber. 15. The vehicular brake system according to claim 14, wherein the fourth pressure chamber forms a reaction-force chamber, such that a reacting hydraulic pressure supplied to the reaction-force chamber applies a reaction force to the operation part. 16. A vehicular brake system comprising: a cylinder;an input piston supported freely movably in an axis direction in the cylinder;an operation part connected to the input piston;a pressurizing piston disposed coaxially with the input piston and supported freely movably in an axis direction in the cylinder, wherein the pressurizing piston is configured to be pushed by the input piston when a malfunction occurs;means for setting a control hydraulic pressure that corresponds to an operation force applied to the input piston through the operation part;means for generating braking hydraulic pressure by supplying the control hydraulic pressure set by the means for setting to the pressurizing piston;means for regulating a braking hydraulic pressure for each of wheels individually, wherein the braking hydraulic pressure is generated by the means for generating;a hydraulic pressure source connected to the means for generating and the means for regulating; andmeans for absorbing the operation force applied to the input piston through the operation part, whereinthe means for generating supplies the control hydraulic pressure to a first pressure chamber disposed on one side of the input piston with respect to a moving direction thereof, or to a second pressure chamber disposed on the other side of the input piston,the hydraulic pressure source is configured to supply hydraulic fluid to the first pressure chamber or the second pressure chamber and to the means for regulating, and part of a supply line from the hydraulic pressure source to the first pressure chamber or the second pressure chamber and part of a supply line from the hydraulic pressure source to the means for regulating are common, andthe means for absorbing includes a communication passage provided to the input piston that is configured to supply and discharge hydraulic fluid between the first pressure chamber and the second pressure chamber when open, so that a pushing force of the input piston is not transmitted to the pressurizing piston when the communication passage is open.