JP2000025598A - Braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking device in which the power consumption to prevent the brake drag is reduced. SOLUTION: A normally-open opening/closing switching solenoid valve 11 to be controlled by a control device 12 is provided parallel to a pressure reduction opening variable solenoid valve 10R between a wheel cylinder 6R and a reservoir 4, the control device 12 closes the normally-open opening/closing switching solenoid valve 11 only when a brake is applied, a brake fluid in the wheel cylinder 6R flows into the reservoir 4 from the normally-open opening/ closing switching solenoid valve 11 while the pressure reduction opening variable solenoid valve 10R large in the power consumption when the brake is not applied is non-energized (closed), and the brake drag is eliminated, and the power consumption required therefor can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake braking device suitably used to apply a braking force to, for example, a vehicle or the like.

[0002]

2. Description of the Related Art In a conventional braking device, an operation amount of a brake operation member is electrically detected by a sensor, and a braking force having a magnitude corresponding to the detection result (a target braking force determined based on a detection signal of the operation amount). ) And an actually measured braking effect, and a booster valve provided between a hydraulic pressure supply source for generating high-pressure brake fluid and a wheel cylinder, and a brake fluid released from the wheel cylinder and the pressure are stored. And a pressure reducing valve provided between the reservoir and the reservoir to control the brake fluid pressure supplied to the wheel cylinder.

[0003] In the above-mentioned conventional braking device, at the time of a brake operation, the opening of a solenoid-operated pressure-increasing opening variable solenoid valve (pressure-increasing valve) is controlled so that the brake fluid pressure supplied from a fluid pressure source to a wheel cylinder is controlled. And the brake fluid pressure in the wheel cylinder is increased to generate a braking force in the wheel cylinder corresponding to the operation amount. At this time, the pressure-reducing opening variable solenoid valve (pressure reducing valve) is closed to keep the communication between the wheel cylinder and the reservoir shut off.

[0004] When the brake braking force is held, the brake fluid pressure in the wheel cylinder is maintained by closing the pressure-opening variable solenoid valve while keeping the pressure-decreasing opening variable solenoid valve closed. He keeps his power constant.

On the other hand, when the brake operation is released, the brake fluid pressure released from the wheel cylinder to the reservoir is regulated by controlling the opening of the electromagnetic type pressure reducing opening variable solenoid valve.
The brake fluid pressure in the wheel cylinder is reduced to generate a braking force in the wheel cylinder corresponding to the operation amount. At this time, the pressure-increasing opening variable electromagnetic valve is closed to keep the communication between the hydraulic pressure supply source and the wheel cylinder shut off.

When the brake is not operated, it is necessary to close the pressure-increasing opening variable solenoid valve so that the brake fluid pressure is not supplied from the fluid pressure supply source to the wheel cylinder.

Here, in order to set the opening of the variable-position solenoid valve to a desired opening, it is necessary to hold the armature at a plurality of intermediate positions corresponding to the magnitude of the current supplied to the solenoid. is there. Therefore, the part where the slope of the line of suction force at which the coil sucks the armature becomes smaller than the increase rate (the slope of the line of required suction force) of the required suction force (spring resistance) required for the armature to move against the spring. The shape of the armature is devised so that it can be done.

[0008] Thus, as shown in FIG. 5, given a current value I ₁ or more current to the coil, suction coil sucks armature in the moving range of the armature (between the movement amount 0 of the armature of the maximum) Since the force exceeds the required suction force, the armature is moved and held to the position where the amount of movement is maximum. When a current having a current value of I ₂ (I ₂ > I ₁ ) is applied to the coil, the armature moves because the required attraction force is larger than the attraction force at which the coil attracts the armature in a portion where the amount of movement of the armature is δ ₂ or more. held by the movement to the position of the movement amount [delta] _2, given a small current I ₃ than the current I ₂ in the coil, should the suction force with a small [delta] ₃ or more portions than _second movement of the armature is [delta] is a coil to is larger than the suction force for sucking the armature is held by the moving armature to the position of the movement amount [delta] _2.

That is, in order to move and hold the armature at a position corresponding to the required valve opening, a current having a current value at which the suction force by which the coil sucks the armature and the required suction force become equal in the amount of the movement. Is given to the coil. In a solenoid valve with a variable opening, the attraction force does not increase so much even when the armature moves and approaches the coil in order to have such a movement amount-attraction force characteristic.
Therefore, if the armature is to be held at the position where the amount of movement is the maximum, that is, the valve is fully open if the valve is normally closed,
It is necessary to continue to supply a current having a value enough to generate a suction force exceeding the required suction force when the maximum movement amount is the maximum. In addition, the variable-opening solenoid valve for increasing or decreasing pressure used in the braking device needs a spring force enough to oppose the brake fluid pressure because it is provided in the passage where the brake fluid pressure is applied, and therefore opposes the spring force. The required suction force increases, and the current value for maintaining the valve fully open position also increases.

When the vehicle is provided with four wheel brakes in combination with the left and right front and rear wheels, at least two wheel cylinders of the left and right front wheels and the left and right rear wheels are provided.
Two sets of variable-pressure opening solenoid valve for pressure increase and variable-pressure opening solenoid valve for pressure reduction, up to four wheel cylinders at the left and right front and rear, respectively. Therefore, the power consumption of the entire braking device becomes very large.

For this reason, in order to reduce the power consumption of the entire braking device, it is sufficient to supply the current to the pressure-increasing opening variable solenoid valve only when the brake is operated (when the wheel cylinder is pressurized). A normally-closed valve is used, and a normally-closed valve is used as the pressure-decreasing opening variable electromagnetic valve so that current needs to be supplied only when the brake operation is released (when the wheel cylinder is depressurized).

[0012]

[Problems to be solved by the invention]

In the above braking device, since the pressure-reducing opening variable solenoid valve is normally closed, if the valve is closed without supplying current to the pressure-reducing opening variable solenoid valve when the brake is not operated, the brake in the wheel cylinder is closed. The liquid is confined between the pressure-increasing opening variable solenoid valve which is also closed. At this time, if the brake fluid in the wheel cylinder expands due to a rise in temperature or the like, the brake will be dragged. However, if the pressure-reducing opening variable solenoid valve is opened or energized when the brake is not operated in order to prevent the brake from being dragged, the power consumption of the pressure-reducing opening variable solenoid valve is large as described above, so that the braking is performed. There is a problem that the power consumption of the entire apparatus is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a braking device that prevents a brake from being dragged and that reduces the power consumption required for the braking.

[0015]

SUMMARY OF THE INVENTION A braking device according to the present invention is provided on a wheel and generates a braking force corresponding to the magnitude of the supplied brake fluid pressure, and a brake fluid pressure of the wheel cylinder. A hydraulic pressure supply source for generating a high-pressure brake fluid for increasing pressure, a reservoir for storing brake fluid that has been released to reduce the brake fluid pressure of the wheel cylinder, the hydraulic pressure supply source and the wheel cylinder, A normally-closed pressure-increasing opening variable solenoid valve that controls brake fluid pressure supplied to the wheel cylinder, and is provided between the wheel cylinder and the reservoir and is released from the wheel cylinder. A normally-closed pressure-reducing opening variable solenoid valve for controlling brake fluid pressure, and a control for controlling the opening of the pressure-increasing opening variable solenoid valve and the pressure-reducing opening variable solenoid valve And the location, in the braking apparatus consisting of,
Between the wheel cylinder and the reservoir, a normally open on / off switching electromagnetic valve whose opening and closing is controlled by the control device is provided in parallel with the pressure reducing opening variable electromagnetic valve, and the control device is operated only when the brake is operated. The normally open switching solenoid valve is closed.

With this configuration, when the brake is not operated, the brake fluid in the wheel cylinder is released from the normally open on / off switching electromagnetic valve to the reservoir.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A braking system according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a state when the brake is not operated. The brake pedal 1 is for generating a braking force in a braking device when an operator steps on the brake pedal, and according to an operation amount of the brake pedal 1 (stroke in the present embodiment), a wheel cylinder 6F,
A braking force is generated in 6F, 6R, and 6R. The brake pedal 1 is provided with a sensor 2 (a stroke sensor is used in the present embodiment) for detecting an operation amount, and the sensor 2 detects an operation amount of the brake pedal 1.

The brake pedal 1 is connected to the master cylinder 3. When the operator depresses the brake pedal 1, the piston in the master cylinder 3 slides, and the pressure of the brake fluid on the downstream side is reduced. 1 increases in accordance with the operation amount of the brake pedal 1 to give the operator a feeling of depressing the brake pedal 1. When there is an abnormality in the path of the braking force generation due to the pressure supply from the hydraulic pressure supply source described later, the brake hydraulic pressure can be supplied from the master cylinder 3 to the wheel cylinder to generate the braking force. . Further, the master cylinder 3 is provided with a reservoir 4 for storing the brake fluid of the braking device of the present embodiment in the open to the atmosphere.

The hydraulic pressure supply source 5 comprises a motor pump 5a for discharging the brake fluid from the reservoir 4, an accumulator 5b for storing the discharged brake fluid, and a pressure sensor 5c for sensing the pressure of the brake fluid in the accumulator 5b. And a pressure accumulator 5b sensed by a pressure sensor 5c by a control device 12 described later.
The drive of the motor pump 5a is controlled such that the brake fluid pressure is always within a predetermined pressurized range.

The passage to which the brake fluid pressure is supplied from the fluid pressure supply source 5 is branched into four branches, two to the front wheel side wheel cylinders 6F, 6F and two to the rear wheel side wheel cylinders 6R, 6R, respectively. It is connected. The wheel cylinders 6F, 6F, 6R, 6R generate a braking force by being supplied with a brake fluid pressure from a fluid pressure supply source 5. The wheel cylinders 6F, 6F, 6R, 6R
And the wheel cylinders 6F, 6F, 6
By releasing the brake fluid pressure in R and 6R to the reservoir 4, the brake fluid pressure is made equal to the atmospheric pressure, and the generated braking force is eliminated. The wheel cylinders 6F, 6F, 6R, 6R include sensors 7, 7, 7, 7,
7 are provided.

The front wheel cylinders 6F, 6F
F is also in communication with the master cylinder 3 via the path switching valves 8, 8, and can generate a braking force also by supplying brake fluid pressure from the master cylinder 3. The path switching valves 8, 8 are provided on the front wheel side wheel cylinders 6F, 6F.
A path for supplying hydraulic pressure from the hydraulic pressure supply source 5 to release the hydraulic pressure to the reservoir 4, and a path for supplying hydraulic pressure from the master cylinder 3 and releasing the hydraulic pressure to the reservoir 4 via the master cylinder 3. And.

The hydraulic pressure source 5 and the wheel cylinders 6F, 6
F, 6R, 6R are provided with normally-closed pressure-increasing opening variable solenoid valves 9F, 9F, 9R, 9R. Further, between the wheel cylinders 6F, 6F, 6R, 6R and the reservoir 4, a normally-closed pressure-reducing opening variable solenoid valve 10F, 10F,
10R, 10R are provided. Opening variable solenoid valves 9F, 9F, 9R, 9R for increasing pressure and variable opening solenoid valves 10 for reducing pressure
Each of F, 10F, 10R, and 10R has a structure of a variable opening solenoid valve as described in the related art, and adjusts the opening of the valve according to the magnitude of a current supplied from a control device 12 described later. The valve can be changed, and when no current is supplied, the valve is closed.

Variable pressure opening variable solenoid valve 10R, 1 on the rear wheel side
Normally open / close switching electromagnetic valves 11 and 11 are provided in parallel with 0R, and the open / close switching electromagnetic valves 11 and 11 also communicate the wheel cylinders 6R and 6R on the rear wheel side with the reservoir 4. Variable opening solenoid valves for pressure 9F, 9F, 9R, 9R
And pressure-reducing opening variable solenoid valves 10F, 10F, 10R, 1
Unlike 0R, the opening of the valve cannot be changed,
When a current equal to or more than a predetermined value is supplied, the valve is closed, and when no current is supplied, the valve is open. The open / close switching solenoid valves 11 and 11 have a simple shape of the armature and the coil. Therefore, the closer the armature and the coil are, the smaller the magnetic resistance of the magnetic circuit formed by the coil and the armature is. It has a movement amount-suction force characteristic that the suction force increases.

As shown in FIG. 2, the current I ₄
When the above current is applied, the suction force at which the coil sucks the armature in the movement range of the armature (between the movement amount of the armature 0 and the maximum) exceeds the suction force required for the armature to move against the spring. Therefore, the armature is moved and held to the position where the amount of movement is maximum.
Once the armature has moved to the position of movement amount up to the armature also lower the current value to only the current is caused to generate the required suction force on the moving amount maximum position of the armature (current value I ₅ or more current) Position can be held. That is, once the valve is opened, the valve can be kept open even if the current is reduced to a predetermined value.

Further, the passage communicating between the wheel cylinders 6R, 6R provided with the open / close switching solenoid valves 11, 11 and the reservoir 4 only recirculates the brake fluid having a volume corresponding to the thermal expansion of the brake fluid. , The passage area is very small. Therefore, since the opening / closing switching solenoid valves 11, 11 themselves are also very small, the opening / closing switching solenoid valves 11, 11 themselves are used.
Since the spring force of the spring used for the spring 11 is also small and the required suction force (spring resistance) is small, it can be driven with a small current value.

The braking device of the present embodiment is provided with a control device 12 for controlling the operation of the entire braking device. The control device 12 reads the operation amount of the brake pedal 1 from the sensor 2, reads the pressures of the wheel cylinders 6F, 6F, 6R, 6R from the sensors 7, 7, 7, 7, and increases the opening degree variable solenoid valves 9F, 9F for increasing pressure. , 9R, 9R and pressure-reducing opening variable solenoid valves 10F, 10F, 10R, 10R
The valve opening is controlled by controlling the value of the current supplied to the valve to obtain the pressure corresponding to the operation amount. Further, the driving of the motor pump 5a is controlled such that the pressure of the accumulator 5b read from the sensor 5c of the hydraulic pressure supply source 5 is always within a predetermined range. Further, the path switching valve 8,
By supplying / stopping a current to the switching valve 8 and the opening / closing switching solenoid valves 11, 11, the switching of the path and the connection / disconnection of the passage are performed.

The operation of the control device 12 of the braking device according to the present embodiment will be described below with reference to the time chart of FIG. The time chart of FIG. 3 shows one of the wheel cylinders 6R, 6R on the rear wheel side.
This is for the pressure increase and pressure reduction paths to R, but the same applies to the other wheel cylinder 6R.

When the brake pedal 1 is not operated by the operator and the brake is not operated (when the operation amount is 0),
No current is supplied from the control device 12 to all of the pressure-increasing opening variable electromagnetic valve 9R (normally closed), the pressure-decreasing opening variable electromagnetic valve 10R (normally closed), and the open / close switching electromagnetic valve 11 (normally open). , Variable pressure opening solenoid valve 9R and variable pressure opening solenoid valve 10R
Is closed and the open / close switching electromagnetic valve 11 is opened. Accordingly, the communication between the hydraulic pressure supply source 5 and the wheel cylinder 6R is interrupted, and the wheel cylinder 6R and the reservoir 4 communicate with each other via the open / close switching electromagnetic valve 11 which is open.
The brake fluid in the wheel cylinder 6 </ b> R
And is open to the reservoir 4 so that the pressure is equal to the atmospheric pressure.

When the brake pedal 1 is depressed by the operator (when the operation amount is increased), the pressure-increasing opening variable solenoid valve 9R operates the wheel corresponding to the operation amount of the brake pedal 1 detected by the sensor 2. The opening of the valve is adjusted by adjusting the current value supplied by the control device 12 so that the pressure of the cylinder 6R is obtained. The opening / closing switching electromagnetic valve 11 is controlled by the control device 12 as shown in FIG.
The moving amount - if mentioned suction force diagram, once the the valve closed state (after the elapse of sufficient time for the valve closing operation is completed) after the closing supplied with a current value I ₄ or more current it is possible to generate the required suction force than the suction force to maintain supplied reduced to I ₅ or more current values. At this time, the pressure-increasing opening variable electromagnetic valve 9R is in the valve-opening (not necessarily fully open) operation, and the pressure-decreasing opening variable electromagnetic valve 10R and the open / close switching electromagnetic valve 11 are in the valve closed state. Therefore, the hydraulic pressure supply source 5 and the wheel cylinder 6R communicate with each other, and the wheel cylinder 6R and the reservoir 4
Communication with the wheel cylinder 6R
The brake fluid inside is in a pressure increasing process by receiving a pressure supply from the hydraulic pressure supply source 5 without escaping to the reservoir 4.

When the braking force is held by the operator while the brake pedal 1 is being depressed (when the operation amount is constant), the pressure increasing opening variable solenoid valve 9R and the pressure reducing opening variable solenoid valve 10R are switched to each other. No current is supplied from the control device 12, and only a small current value capable of generating a suction force equal to or greater than a required suction force for maintaining the valve closed state is supplied to the open / close switching solenoid valve 11. At this time, all of the pressure-increasing opening variable electromagnetic valve 9R, the pressure-decreasing opening variable electromagnetic valve 10R, and the open / close switching electromagnetic valve 11 are in the closed state. Therefore, the hydraulic pressure source 5 and the wheel cylinder 6R and the wheel cylinder 6R
Since the communication between R and the reservoir 4 is interrupted, the brake fluid in the wheel cylinder 6R does not receive the pressure supply from the hydraulic pressure supply source 5 and does not escape to the reservoir 4 and the pressure increases during the brake operation. The maintained pressure is maintained.

When the operator releases the brake pedal 1 to release the brake operation (when the operation amount decreases), the pressure-decreasing opening variable solenoid valve 10R responds to the operation amount of the brake pedal detected by the sensor 2. The valve opening is adjusted by adjusting the current value supplied by the control device 12 so that the pressure of the wheel cylinder is obtained. Also,
The opening / closing switching electromagnetic valve 11 is supplied by the control device 12 with only a small current value capable of generating a suction force greater than a required suction force for maintaining the valve closed state. At this time, the pressure-decreasing opening variable electromagnetic valve 10R is in a valve-opening (not necessarily fully open) operation, and the pressure-increasing opening variable electromagnetic valve 9R and the open / close switching electromagnetic valve 11 are in a valve closed state. Therefore, the communication between the hydraulic pressure supply source and the wheel cylinder is interrupted, and the wheel cylinder 6
The communication between R and the reservoir 4 is performed by the opening degree variable solenoid valve 10R for pressure reduction.
, The brake fluid in the wheel cylinder 6R is released to the reservoir 4 without receiving a pressure supply from the hydraulic pressure supply source 5 and is in a pressure reducing process.

When the operator depresses the brake pedal 1 completely (when the operation amount becomes 0), the brake returns to the non-operation state.

The pressure-increasing opening variable solenoid valve 9R is energized only when the brake is operated, and is in a valve-open state, and the pressure-decreasing opening variable electromagnetic valve 10R is energized only when the brake operation is released, and is in a valve-open state. The open / close switching electromagnetic valve 11 is energized only when the brake is operated, when the brake is held, and when the brake is released, that is, only when the brake is operated, and the valve is closed.
However, there is a delay in the timing of stopping the energization of the open / close switching electromagnetic valve 11 so that the open / close switching electromagnetic valve 11 is opened after the brake operation is completely completed.

The operation of the front wheels is described with reference to the pressure-increasing opening variable solenoid valves 9F and 9F and the pressure-reducing opening variable solenoid valve 10F.
F and 10F are the same as the operation of the above-described rear wheel pressure increasing opening variable solenoid valve 9R and the pressure reducing opening variable solenoid valve 10R for the rear wheels. The communication between the master cylinder 3 and the wheel cylinders 6F, 6F is interrupted by communicating the variable solenoid valves 9F, 9F, and the passages between the pressure-reducing opening variable solenoid valves 10F, 10F and the wheel cylinders 6F, 6F, thereby breaking the brake. During non-operation, the passages between the pressure-increasing opening variable solenoid valves 9F, 9F and the pressure-reducing opening variable solenoid valves 10F, 10F and the wheel cylinders 6F, 6F are cut off to disconnect the master cylinder 3 and the wheel cylinders 6F, 6F. Communicate. Thus, when the brake is not operated, the brake fluid in the wheel cylinders 6F, 6F is released to the reservoir 4 via the master cylinder 3, so that the problem of dragging the brake due to the trapping of the brake fluid does not occur.

In the above-described embodiment, when the brake is operated (when the brake is operated, when the brake is held, and when the brake is released).
Only when the brake is not operated, the normally open / closed switching solenoid valves 11, 1 are energized.
1 communicates with the wheel cylinders 6R, 6R through the wheel cylinders 6R, 6R.
The brake fluid is not confined in the space between R, 9R and the pressure-reducing opening variable solenoid valves 10R, 10R). Therefore, even if the brake fluid expands due to a rise in temperature or the like, the brake fluid pressure in the wheel cylinders 6R, 6R remains at the reservoir 4.
Since the pressure is the same as the atmospheric pressure, the brake will not be dragged.

The open / close switching solenoid valves 11, 11, which require continuous energization during brake operation, have a small current value enough to generate a suction force greater than the required suction force when maintaining the valve closed state as described above. Since only this operation is required, the amount of power consumption is very small as compared with the case where the pressure-decreasing opening variable solenoid valves 10R and 10R are continuously energized and opened by releasing the brake when the brake is not operated.

Next, a braking device according to a modification of the above embodiment will be described with reference to FIG. However, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In the modified example, the master cylinder 13 is of a tandem type, and two independent paths for supplying hydraulic pressure to the wheel cylinders 6F, 6F on the front wheel side are provided.

Further, an opening / closing switching electromagnetic valve 14 is provided in place of the opening / closing switching electromagnetic valves 11, 11. Open / close switching solenoid valve 1
When the valve is open, the two wheel cylinders 6R, 6R can communicate with the reservoir 4, and when the valve is closed, the communication between the wheel cylinders 6R, 6R and the reservoir 4 can be cut off. That is, one open / close switching electromagnetic valve 14 can fulfill the two roles of the open / close switching electromagnetic valves 11 and 11 of the above embodiment. Therefore, the power consumption for one open / close switching electromagnetic valve can be further reduced as compared with the above embodiment.

[0039]

The braking device according to the present invention is provided between a wheel cylinder and a reservoir in parallel with a pressure-reducing opening variable solenoid valve.
A normally open on / off switching electromagnetic valve whose opening and closing is controlled by a control device is provided, and the control device is configured to close the normally open on / off switching electromagnetic valve only when the brake is operated. The brake fluid in the wheel cylinder is released to the reservoir from the normally open on / off switching electromagnetic valve even when the pressure-reducing opening variable electromagnetic valve having a large value is kept non-excited (closed). As a result, it is possible to eliminate the drag of the brake and to reduce the power consumption required for this.

[0040]

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a braking device according to an embodiment of the present invention.

FIG. 2 is a graph showing a movement amount of an armature and an attraction force at each current value of an on-off switching solenoid valve.

FIG. 3 is a time chart illustrating an operation of supplying hydraulic pressure to a wheel cylinder on a rear wheel side of the braking device according to the embodiment of the present invention.

FIG. 4 is a hydraulic circuit diagram illustrating a braking device according to a modification of the embodiment of the present invention.

FIG. 5 is a graph showing a movement amount of an armature and an attractive force at each current value of a variable opening electromagnetic valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Sensor 3 Master cylinder 4 Reservoir 5 Hydraulic pressure supply source 5a Motor pump 5b Accumulator 5c Sensor 6F (front wheel side) wheel cylinder 6R (rear wheel side) wheel cylinder 7 Sensor 8 Route switching valve 9F (front wheel side) )) Variable opening solenoid valve for pressure increase 9R Variable opening solenoid valve for pressure increase (on the rear wheel) 10F Variable opening solenoid valve for pressure reduction (on the front wheel side) 10R Variable solenoid valve for reducing pressure (on the rear wheel side) 11 Opening / closing switching solenoid valve 12 Controller 13 Master cylinder 14 Opening / closing switching solenoid valve

Claims (1)

[Claims] 1. A wheel cylinder provided on a wheel for generating a braking force in accordance with a magnitude of a supplied brake fluid pressure, and a high-pressure brake fluid for increasing the brake fluid pressure of the wheel cylinder is generated. A fluid pressure supply source, a reservoir for storing brake fluid that has been released to reduce the brake fluid pressure of the wheel cylinder, and a reservoir provided between the fluid pressure supply source and the wheel cylinder for supply to the wheel cylinder. A normally-closed pressure-increasing opening variable solenoid valve for controlling the brake fluid pressure to be provided, and a normally-closed depressurization provided between the wheel cylinder and the reservoir for controlling the brake fluid pressure released from the wheel cylinder. And a control device that controls the opening of the pressure-increasing opening variable electromagnetic valve and the pressure-decreasing opening variable electromagnetic valve. Between the wheel cylinder and the reservoir, a normally open on / off switching electromagnetic valve whose opening and closing is controlled by the control device is provided in parallel with the pressure reducing opening variable electromagnetic valve, and the control device is operated only when the brake is operated. A braking device, wherein the normally open on / off switching electromagnetic valve is closed.