JPH10181557A - Hydraulic pressure control device and braking device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and smoothy increase/decrease hydraulic pressure in a hydraulic circuit by arranging a connecting rod around a pressure regulating piston, and inclining the connecting rod by the rotation of the pressure regulating piston to axially move the pressure regulating piston. SOLUTION: A pressure regulating piston 5 is arranged in a hydraulic pressure chamber 12, and a supporting shaft 4 is journalled to a shaft holder 8 fixed to a body 10. A connecting rod 13 is arranged between the pressure regulating piston 5 and the shaft holder 8, and the connecting rod 13 is supported to the pressure regulating piston 5 and shaft holder 8. A seal cap 14 is arranged around the pressure regulating piston 5 and connecting rod 13, and the end part 14a of the seal cap 14 is held between the shaft holder 8 and a body 10 so as to isolate the inside of the seal cap 14 from the hydraulic pressure chamber 12, thus preventing liquid from leaking outside from the supporting shaft 4 of the pressure regulating piston 5. The increase/decrease of hydraulic pressure in a hydraulic circuit can therefore be executed smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure control device capable of smoothly increasing and decreasing the fluid pressure in a fluid pressure control circuit, and more particularly to a fluid pressure control device in a caliper of a vehicle disk brake. Built-in, anti-lock,
The present invention relates to a small and lightweight brake device capable of executing smooth hydraulic pressure control such as traction control.

[0002]

2. Description of the Related Art In recent years, the development of an antilock control device for the purpose of improving driving stability during braking and facilitating a driver's driving operation has been actively promoted. Japanese Patent Application Laid-Open No. Sho 64-4 discloses this type of vehicle antilock control device.
The one described in Japanese Patent No. 7650 is known.

[0003] The anti-lock control device described in the above-mentioned publication includes a brake device which is operated by hydraulic pressure supplied from a master cylinder, an anti-lock control modulator arranged in a pipe connecting the master cylinder and the wheel cylinder, and The ball valve in the modulator is precisely controlled by using a step motor, and the hydraulic pressure supplied to the brake device is increased and decreased to eliminate the wheel locking phenomenon.

However, in the above-described anti-lock control device, a modulator for performing anti-lock control must be provided in the middle of the brake pipe, separately from the brake device mounted on the wheel side. There is a problem that it becomes complicated and complicated.

In order to reduce the size of the antilock control device separately from the above-mentioned conventional example, a brake caliper incorporating a brake fluid pressure control mechanism has been proposed (Japanese Patent Laid-Open No. 61-166759). ). This antilock control device incorporates a piezoelectric brake fluid pressure control mechanism in a brake caliper, and performs brake fluid pressure control by using deformation of a piezoelectric element. However, this device also requires the provision of a displacement member in order to increase the amount of movement of the brake piston provided in the hydraulic control mechanism, which complicates the configuration and increases the manufacturing cost. It is difficult to incorporate a complicated mechanism into the located calipers in terms of weight and size restrictions. In addition, since a complicated mechanism is employed, there are problems that sound and vibration are easily generated, and that fluid pressure control cannot be performed smoothly.

[0006]

Therefore, in order to solve the above-mentioned problems, the present invention arranges a number of connecting rods around a pressure adjusting piston, and inclines the connecting rod by rotating the pressure adjusting piston to thereby adjust the pressure adjusting piston. The present invention provides a small and light hydraulic control device that can easily and smoothly increase and decrease the hydraulic pressure in a hydraulic circuit using a pressure adjusting mechanism that moves in the axial direction. It is an object of the present invention to provide a lightweight and compact brake device incorporated in a caliper of a brake. It is another object of the present invention to use a power motor as a control motor and control the power motor based on position information from a potentiometer, thereby reducing the cost of the entire apparatus.

According to this device, it is possible to smoothly and accurately increase and decrease the hydraulic pressure in the hydraulic circuit, and to obtain a lightweight, compact and low-cost brake device by incorporating this device into a brake caliper. Anti-lock control, traction control,
Fluid pressure control such as automatic braking can be smoothly performed.

[0008]

According to the present invention, there is provided a technical solution, which is disposed in a hydraulic circuit between a hydraulic pressure generating source and an actuator, and controls a hydraulic pressure acting on the actuator. A pressure control device, wherein the device closes a cylinder formed in the main body of the hydraulic pressure control device and a cylinder end portion in the cylinder to form a hydraulic pressure chamber communicating with the hydraulic pressure generation source and the actuator. A shaft holder, a pressure adjustment piston disposed rotatably and axially movable in the hydraulic chamber, a connecting rod connecting the tuning pressure piston and the shaft holder, and a periphery of the pressure adjustment piston and the connecting rod. Provided in
A seal cap for preventing leakage of liquid in the hydraulic chamber, a potentiometer for detecting a rotation angle of the tuning pressure piston, a power motor for rotatingly driving the pressure regulating piston based on position information from the potentiometer, and A solenoid valve arranged in a flow path communicating the room with the hydraulic pressure source,
A hydraulic pressure control device comprising an electronic control unit (ECU) that controls the electromagnetic valve and the power motor,

A cylinder formed in a caliper of a brake device, a slidable brake piston disposed in the cylinder, a shaft holder for closing the cylinder end, and a cylinder defined by the piston and the shaft holder. A hydraulic pressure chamber, a pressure adjusting piston disposed rotatably and axially in the hydraulic pressure chamber, a connecting rod connecting the tuning pressure piston and the shaft holder, and a connecting rod connected to the pressure adjusting piston. , A seal cap for preventing leakage of liquid in the hydraulic chamber, a potentiometer for detecting a rotation angle of the tuning pressure piston, and rotating the pressure regulating piston based on positional information from the potentiometer. A power motor, and an electric motor arranged in a flow path communicating the hydraulic chamber with the master cylinder. A valve, it is a brake device, characterized in that said and an electronic control unit for controlling the solenoid valve and the power motor (ECU).

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view of a hydraulic control device according to the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, FIG. 3 is an enlarged side view of a main part of a pressure adjusting piston and a connecting rod, and FIG. It is a side view in the state where it moved in the axial direction.

In FIG. 1, 1 is a hydraulic pressure generating source, 2 is a quad valve (hereinafter referred to as an electromagnetic valve), 3 is a hydraulic control device, 6 is a power motor for driving the hydraulic control device 3, and 7 is an electronic control device (ECU). ), 30 and 31 are flow paths, 40 is a potentiometer, and 41 is a hydraulic pressure sensor, and these constitute a hydraulic control system. Main body 1 of hydraulic pressure control device 3
0, a cylinder 11 is formed, and an end of the cylinder 11 is closed with a shaft holder 8 so that a hydraulic pressure chamber 12 is formed in the cylinder.
Is formed. The hydraulic chamber 12 is connected to a hydraulic pressure generating source (for example, a master cylinder) 1 via an electromagnetic valve 2 provided in a flow path 30, and to an actuator (for example, a conventional brake device (not shown)) via a flow path 31. Inside the wheel cylinder).

A pressure adjusting piston 5 having a support shaft 4 at the center is disposed in the hydraulic pressure chamber 12.
The support shaft 4 is axially movable and rotatably supported by a shaft holder 8 fixed to a main body 10 via a bearing 9. As shown in FIGS. 2 and 3, a number of connecting rods 13 are arranged between the outer periphery of the pressure adjusting piston 5 and the shaft holder 8, and the ends of the connecting rods 13 are respectively connected to the pressure adjusting piston 5 and the shaft holder 8. Are rotatably supported. A seal cap 14 is arranged around the pressure regulating piston 5 and the connecting rod 13 as shown in FIG.
The end 14a of the seal cap 14 is
And the main body 10 in a liquid-tight manner, thus isolating the inside of the seal cap 14 from the hydraulic pressure chamber 12, and allowing the liquid in the hydraulic pressure chamber 12 to exit from the shaft support portion of the pressure regulating piston 5 support shaft 4 or the like. Prevents leakage.

An end of the support shaft 4 of the pressure adjusting piston 5 is provided with a large gear 16 via a mechanism 15 such as a spline shaft which can move in the axial direction and can transmit a rotational force.
The large gear 16 meshes with a pinion 18 attached to an output shaft 17 of the power motor 6. A spring 19 for urging the large gear 16 to the left in the figure is provided around the end of the support shaft 4.
And the pinion 18 do not move relative to each other in the axial direction. The pressure adjustment mechanism is constituted by the pressure adjustment piston 5, the connecting rod 13, the shaft holder 8, and the like. A potentiometer 40 is attached to the end of the support shaft 4, and the rotation angle (position information) of the pressure adjusting piston 5 can be detected by the potentiometer 40. 20 is a potentiometer 4
0 is a spring seat attached to the support shaft 4 via the center shaft.

In the pressure adjusting mechanism having the above structure, when the support shaft 4 is rotated by the large gear 16, the pressure adjusting piston 5 is also rotated, but the pressure adjusting piston 5 and the shaft holder 8 are rotated.
4, the connecting rod 13 is inclined by .theta. With respect to the axial direction as shown in FIG. 4, and the pressure adjusting piston 5 is moved in FIG. As shown in the figure, the volume in the hydraulic chamber 12 can be increased by moving in the axial direction ΔL. At this time, the seal cap 14 is deformed as the pressure adjusting piston 5 rotates. Pressure adjusting piston 5
In this configuration, a member such as a coil spring is disposed between the pressure adjusting piston 5 and the shaft holder 8 without being limited to the connecting rod 13.
, The pressure adjusting piston 5 can be moved in the axial direction.

The electromagnetic valve 2, the power motor 6, the potentiometer 40 and the hydraulic pressure sensor 41 are provided by an electronic control unit (EC
U) 7, the electronic control unit 7 controls and drives the power motor 6 based on signals from a hydraulic pressure sensor 41, a potentiometer 40, and various sensors (not shown), and controls the solenoid valve 2 to operate. It operates to control the fluid pressure in the fluid pressure control circuit in a manner described below. In addition, a power motor (a small power type motor capable of normal and reverse rotation) is used as the above-described motor, and the rotation angle of the power motor can be controlled by a signal from the potentiometer 40. When the above-described control is performed, a servomotor is generally used as a motor. In this case, however, an encoder is required, which increases the cost of the motor. Instead, a power motor is used, and the power motor is controlled by a position signal from a potentiometer, so that cost can be reduced. Of course, it is also possible to use a servomotor instead of a power motor.

The operation of the hydraulic control device according to the above configuration will be described. [Normal operation state] In a normal state, there is no command from the electronic control unit 7, and the solenoid valve 2 and the power motor 6 do not operate. The cam is in the initial position shown in FIG. Therefore,
In this state, when the hydraulic pressure is generated by the hydraulic pressure generation source 1, the hydraulic pressure is supplied to the flow path 30 → the opened electromagnetic valve 2 → the hydraulic pressure chamber 12 → the flow path 31 → the actuator, and the actuator is operated. When the hydraulic pressure of the hydraulic pressure generating source 1 is released, the liquid in the hydraulic pressure chamber is returned to the hydraulic pressure generating source through the reverse route, and the actuator returns to the initial position.

[Hydraulic Pressure Control in the Hydraulic Pressure Control Circuit] When controlling the hydraulic pressure in the hydraulic pressure circuit, the electronic control unit 7 is controlled based on signals from the hydraulic pressure sensor 41 and other sensors (not shown). Drives the power motor 6 and the solenoid valve 2
Close. By driving the power motor 6, the pinion 18,
The pressure adjusting piston 5 rotates by a predetermined angle via the large gear 16. The rotation of the pressure adjustment piston 5 causes the connecting rod 13 to incline, and the action of the connecting rod 13 causes the pressure adjustment piston 5 to move in the axial direction. As a result, the volume in the hydraulic chamber 12 increases, and The hydraulic pressure is reduced, and the hydraulic pressure acting on the actuator is reduced.

Further, at the time of re-pressurization, when the power motor 6 is rotated in the reverse direction and the pressure adjusting piston 5 is rotated in the initial position direction, the pressure adjusting piston 5 is pushed back into the hydraulic pressure chamber 12 by the action of the connecting rod 13, and Pressurization is performed. At this time, the rotation angle of the pressure adjusting piston 5 is controlled by the power motor 6 controlled by the electronic control unit 7 based on a signal from the potentiometer 40. For this reason, a normal power motor can be used as the motor, and there is no need to use a servomotor or the like with an encoder, and the cost of the entire apparatus can be reduced. As described above, in the present embodiment, since the hydraulic pressure control device is configured independently, it can be disposed in any hydraulic circuit as needed, including the brake circuit, and as a result, the hydraulic pressure in the hydraulic circuit can be increased. It is possible to smoothly increase and decrease the pressure. The connecting rod 13
Is preliminarily inclined as shown in FIG. 4, and by rotating the pressure adjusting piston 5 forward and backward from this state, the pressure adjusting piston 5 is moved in the left and right direction in the figure to pressurize and depressurize the actuator. Can be.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is characterized in that the above-mentioned hydraulic control device is arranged in a brake caliper. In addition,
The same members as those of the first embodiment are denoted by the same reference numerals, and the description of the present embodiment will focus on the differences from the first embodiment. In FIG. 5, 1 is a master cylinder as a hydraulic pressure generating source, 2 is an electromagnetic valve, 3 is a hydraulic control device arranged in a brake caliper, 51 is a brake piston as an actuator provided in the hydraulic control device, and 52 is a brake piston. A disk pad provided on the brake piston; 53, a brake disk; 6, a power motor for driving a hydraulic control device;
Denotes an electronic control unit (ECU), and 30 denotes a flow path, and these constitute a brake system. A cylinder 11 is formed in a main body 50 of the hydraulic pressure control device 3 (in this case, a caliper of a disc brake also serves as the caliper), and a brake piston 51 is slidably disposed in the cylinder 11. ing. As is well known, a disc pad 52 is attached to the brake piston 51.

The hydraulic chamber 12 is formed in the main body 50 by the cylinder 11, a brake piston 51 slidably disposed on the cylinder 11, and a shaft holder 8 closing an end of the cylinder.
The hydraulic chamber 12 communicates with the master cylinder 1 as a hydraulic pressure generation source via an electromagnetic valve 2 provided in a flow path 30. A pressure adjustment piston 5 having a support shaft 4 at the center is disposed in the hydraulic pressure chamber 12, and the support shaft 4 of the pressure adjustment piston 5 is connected to a shaft holder 8 fixed to a main body 50 via a bearing 9. And is rotatably supported in the axial direction. As shown in FIGS. 2 and 3, a number of connecting rods 13 are arranged between the outer periphery of the pressure adjusting piston 5 and the shaft holder 8, and the ends of the connecting rods 13 are respectively connected to the pressure adjusting piston 5 and the shaft holder 8. Are rotatably supported. A seal cap 14 is disposed around the pressure regulating piston 5 and the connecting rod 13 as shown in FIG. 5, and an end of the seal cap 14 is sandwiched between the shaft holder 8 and the caliper body 50 in a liquid-tight manner. Thus, the inside of the seal cap 14 is isolated from the hydraulic pressure chamber, and the liquid in the hydraulic pressure chamber 12 is prevented from leaking outside from the shaft support portion of the pressure regulating piston 5 support shaft 4 or the like.

An end of the support shaft 4 of the pressure adjusting piston 5 is provided with a large gear 16 via a mechanism 15 such as a spline shaft which can move in the axial direction and can transmit a rotational force.
The large gear 16 meshes with a pinion 18 attached to the output shaft of the power motor 6. A spring 19 for biasing the large gear 16 to the left in the figure is provided around the end of the support shaft 4.
The pinion 6 and the pinion 18 are engaged so that there is no relative movement in the axial direction. The pressure adjustment mechanism is constituted by the pressure adjustment piston 5, the connecting rod 13, the shaft holder 8, and the like. A potentiometer 40 is fixed to the end of the support shaft 4, and the rotation angle (position information) of the pressure adjustment piston 5 can be detected by the potentiometer. 20 is a potentiometer 4
0 is a spring seat attached to the support shaft 4 through the support shaft 4.

The above-mentioned solenoid valve 2, power motor 6, and potentiometer 40 are connected to an electronic control unit (ECU) 7, which is based on a signal from a speed sensor (not shown), a potentiometer 40 and the like. Then, the power motor 6 is driven to rotate, and the electromagnetic valve 2 is operated to execute antilock control in a manner described later. In the drawing, reference numeral 21 denotes a seal member between the brake piston 51 and the main body 50.

The operation of the brake device according to the above configuration will be described. [During Normal Braking] During normal braking, there is no command from the electronic control unit 7, and the solenoid valve 2 and the power motor 6 do not operate. The pressure adjusting piston 5 is in the initial position shown in FIG. Therefore, in this state, when the brake pedal is depressed and a hydraulic pressure is generated in the master cylinder 1, the hydraulic pressure is changed from the master cylinder 1 to the opened electromagnetic valve 2 to the flow path 30.
Is supplied to the hydraulic chamber 12 to move the brake piston 51 to perform a braking action. At this time, the pressure adjustment piston 5
Does not move because the large gear 16 does not rotate. When the brake pedal is released, the brake fluid in the hydraulic chamber is returned to the master cylinder through the reverse route, and the brake is released.

[Anti-lock control] When the brake pedal is depressed to apply a brake to the vehicle, the master cylinder 1
Generates hydraulic pressure. This hydraulic pressure is supplied to the hydraulic pressure chamber 12 in the brake device as described above, and moves the brake piston 51 to apply a braking force to the wheels. By the way, in this state, the state of the wheels is constantly detected by a speed sensor or the like, and a detection signal is input to the electronic control unit. Based on the input, the electronic control unit performs wheel speed, slip ratio, Calculate deceleration, etc. Then, the skid state of the wheels is evaluated based on the calculation result, and the electromagnetic valve 2 and the power motor 6 are controlled as described below to execute various modes such as reducing, maintaining, and re-pressurizing the brake fluid pressure.

That is, when the wheels are locked during traveling and a brake release signal is output from the electronic control unit (ECU) 7, the solenoid valve 2 is closed and the power motor 6 is driven, so that the pinion 18 and the large gear 16 are moved. Pressure regulating piston 5 via
Rotates. The rotation of the pressure adjustment piston 5 causes the connecting rod 13 to incline and the pressure adjustment piston 5 to move in the axial direction. As a result, the volume in the hydraulic pressure chamber 12 increases, the brake fluid pressure is reduced, and the braking force is reduced. It is weakened and the locked state of the wheel is released.

Further, at the time of re-pressurization, when the power motor 6 is rotated in the reverse direction and the pressure-regulating piston 5 is rotated in the initial position direction, the pressure-regulating piston 5 is pushed back into the hydraulic chamber 12, and re-pressurization is executed. . Further, when a command for the brake fluid pressure holding state is issued, the power motor 6 stops and holds the brake fluid pressure in the fluid pressure chamber. At this time, the rotation angle of the power motor 6 is controlled by a signal from the potentiometer 40.

The hydraulic pressure control (decompression, holding, re-pressurization) of the brake device is performed for each wheel independently or for each wheel of each channel according to the state of each wheel. The release of the antilock control is performed when there is no signal from the electronic control unit. That is, when the signal from the electronic control unit disappears, the solenoid valve 2 is opened and the pressure adjusting piston is returned to the initial state by the power motor 6 to be in a state shown in FIG.

In the case where the connecting rod 13 is tilted in advance and the pressure adjusting piston is rotated in the direction of submerging from the hydraulic chamber based on this state,
As described above, the hydraulic pressure in the hydraulic chamber can be reduced,
As a result, antilock control can be performed. Further, when the cylinder is rotated in the direction in which the hydraulic chamber is pushed into the hydraulic chamber, the hydraulic pressure in the hydraulic chamber can be increased, whereby traction control and automatic brake control can be executed.

For example, when a slip occurs on the wheels when the vehicle starts, or when the distance between the vehicles is short, the solenoid valve 2 is closed and the pressure regulating piston 5 is rotated in a direction to push out into the hydraulic chamber. The brake fluid pressure in the chamber 12 is increased to apply a brake to the wheels. In traction control, the state of the wheels is constantly detected by a speed sensor, and a detection signal is input to a known electronic control device, and the electronic control device calculates wheel speed, slip rate, deceleration, etc. based on the input. I do. Then, the slip state of the wheels is evaluated based on the calculation result, and the solenoid valve 2 and the power motor 6 are controlled to execute various modes such as reduction, holding, and re-pressurization of the brake fluid pressure in the same manner as in the above-described antilock control. I do.

When an inter-vehicle distance sensor (not shown) detects that the inter-vehicle distance has fallen within a predetermined value, the solenoid valve 2 and the power motor 6 are controlled by a signal from the electronic control unit to increase the brake fluid pressure. Various aspects, such as pressure, hold, pressure reduction, etc., can be performed to activate automatic braking. As described above, in this example, since the hydraulic pressure control device is provided in the brake caliper, the size and weight of the brake device can be reduced, and the increase and decrease of the brake hydraulic pressure can be smoothly performed.

[0031]

As described above in detail, according to the present invention, the pressure control piston is disposed in the hydraulic chamber formed in the main body of the hydraulic pressure control device, and a number of connecting rods are disposed around the pressure control piston. By controlling the axial movement amount of the pressure adjusting piston by inclining the connecting rod by rotation, the volume of the hydraulic chamber can be controlled, and the hydraulic pressure acting on the actuator can be increased or decreased. In a brake device in which this hydraulic pressure control device is incorporated in a brake caliper, anti-lock control, traction control, and automatic brake control can be executed smoothly, and the size and weight of the brake device can be reduced. Also,
Various brake controls can be executed by using the state in which the connecting rod is tilted in advance as a reference. In addition, the brake device built into the caliper can reduce the weight under the spring of the vehicle suspension, and furthermore, it uses a potentiometer to detect the rotation angle of the pressure adjustment piston and controls the power motor. This eliminates the need for a high-priced encoder that controls the operation of the device, and can achieve excellent operational effects such as reduction in cost of the entire apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a hydraulic pressure control device as a first embodiment according to the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is an enlarged side view of a main part of a pressure adjusting piston and a connecting rod in FIG. 1;

FIG. 4 is a side view showing a state where a pressure adjustment piston has moved in an axial direction.

FIG. 5 is a schematic configuration diagram of a brake device as a second embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pressure generation source (master cylinder) 2 Solenoid valve 3 Hydraulic pressure control device 4 Support shaft 5 Pressure adjustment piston 6 Power motor 7 Electronic control device 10, 50 Main body 11 Cylinder 12 Hydraulic pressure chamber 13 Connecting rod 14 Seal cap 15 Spline mechanism 16 Large Gear 17 Output Shaft 18 Pinion 19 Spring 20 Spring Seat 30, 31 Flow Path 40 Potentiometer 41 Hydraulic Pressure Sensor 51 Brake Piston 52 Disk Pad

Claims (2)

[Claims] 1. A hydraulic pressure control device (3) arranged in a hydraulic circuit between a hydraulic pressure generating source (1) and an actuator for controlling a hydraulic pressure acting on said actuator, said device comprising: A cylinder 11 formed in the control device main body 10; a shaft holder 8 for closing a cylinder end to form a hydraulic chamber 12 communicating with the hydraulic pressure source 1 and the actuator in the cylinder 11; 12, a pressure adjusting piston 5 arranged rotatably and axially movable in 12, a connecting rod connecting the tuning pressure piston and the shaft holder, and a liquid provided around the pressure adjusting piston and the connecting rod. A seal cap 14 for preventing leakage of liquid in the pressure chamber, a potentiometer 40 for detecting a rotation angle of the tuning pressure piston, A power motor 6 for rotationally driving a pressure adjusting piston based on position information; and a flow path 30 for communicating the inside of the hydraulic chamber 12 with the hydraulic pressure generating source 1
A hydraulic pressure control device comprising: an electromagnetic valve 2 disposed in the inside; and an electronic control unit (ECU) 7 for controlling the electromagnetic valve 2 and the power motor 6. 2. A cylinder 11 formed in a caliper of a brake device, a slidable brake piston 4 disposed in the cylinder 11, a shaft holder 8 closing an end of the cylinder 11, a piston and a shaft. A hydraulic pressure chamber 12 partitioned in a cylinder 11 by a holder 8, a pressure adjusting piston 5 arranged in the hydraulic pressure chamber 12 so as to be rotatable and axially movable, and a pressure adjusting piston and the shaft holder. A connecting rod to be connected; a seal cap 14 provided around the pressure regulating piston and the connecting rod to prevent leakage of liquid in a hydraulic chamber; a potentiometer 40 for detecting a rotation angle of the pressure regulating piston; and the potentiometer 40 A power motor 6 for rotationally driving the pressure regulating piston based on positional information from Passage 30 for communicating the chamber 12 and the master cylinder
A brake device comprising: a solenoid valve 2 disposed in the inside; and an electronic control unit (ECU) 7 for controlling the solenoid valve 2 and the power motor 6.