JP2961910B2 - Manual / Electric dual brake system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manual / electric dual system brake system for selectively operating a brake of a vehicle wheel by a master cylinder and an electric control hydraulic pressure source. It is related to technology for improving the performance.

[0002]

2. Description of the Related Art An example of a manual / electric dual system brake system is described in Japanese Patent Application Laid-Open No. 63-20256 of the present applicant. This consists of (a) a master cylinder that generates hydraulic pressure in response to operation of a brake operating member such as a brake pedal, (b) a wheel cylinder that operates a brake that suppresses rotation of wheels, and (c) a brake operating member. (D) the higher the hydraulic pressure of the master cylinder and the electrical control hydraulic pressure source, which generates the hydraulic pressure at a height based on the brake operation amount that is the operation force or operation stroke of the master cylinder. And a high pressure side selector for transmitting the hydraulic pressure of the wheel cylinder to the wheel cylinder. If the electric control hydraulic pressure source breaks down, its hydraulic pressure is often lower than the normal value, so if the normal value of the hydraulic pressure of the electric control hydraulic pressure source is set higher than the hydraulic pressure of the master cylinder, If the electric control hydraulic pressure source is normal, the high pressure side selector selects the electric control hydraulic pressure source as the hydraulic pressure source for the wheel cylinder, and if the electric control hydraulic pressure source fails, the master cylinder is selected as the hydraulic pressure source for the wheel cylinder.

[0003]

However, according to a subsequent study by the present applicant, the manual / electric dual brake system has a failure mode in which hydraulic pressure is generated in the wheel cylinders even when the brake is not being operated. It turned out that there was room to assume. Hereinafter, an example in which the failure mode is realized will be specifically described.

The electric control hydraulic pressure source is, for example, of a type that changes the hydraulic pressure of a wheel cylinder based on the displacement of an electrically operated valve element. Even when the brake operation is released while the hydraulic pressure is being generated, the valve may be locked (fixed) at that position and the wheel cylinder may continue to generate hydraulic pressure. Locking of the valve in the operating position in this way means that the electric control hydraulic pressure source has failed.However, the high pressure side selector determines that the hydraulic pressure of the electric control hydraulic pressure source is higher than the hydraulic pressure of the master cylinder. As long as the pressure is not lowered, the electric control hydraulic pressure source is continuously selected as the wheel cylinder hydraulic pressure source. Therefore, even if the brake operation is released, the hydraulic pressure continues to be generated in the wheel cylinder, and the brake will continue to operate.

An object of the present invention is to provide a manual / electric dual-system brake system which guarantees that the hydraulic pressure of a wheel cylinder always becomes zero when a brake operating member is in a non-operating state based on the above findings. It was done.

[0006]

The gist of the present invention is to provide a manual / electric dual brake system.
(A) The hydraulic pressure is generated according to the operation of the brake operating member.
And (b) a brake to suppress wheel rotation.
Brake cylinder and (c) brake operation
Generate hydraulic pressure of height based on work volume by electric control
Electric control hydraulic pressure source, (d) master cylinder and electric control hydraulic pressure
Source as the hydraulic pressure source for the wheel cylinder
Independent of (e) electrically controlled hydraulic pressure source
The master cylinder fluid pressure as pilot pressure
Is activated and its pilot pressure is substantially zero
In this state, the wheel cylinder contains hydraulic fluid at atmospheric pressure
While communicating with the atmospheric pressure chamber, the pilot pressure is substantially zero.
If not, disconnect the wheel cylinder from the atmospheric pressure chamber
And a pilot-type open / close valve .

[0007] One embodiment of the pilot-type on-off valve has a valve element that operates using the hydraulic pressure of the master cylinder as the pilot pressure, and the pilot pressure is substantially zero, that is, the operation of the brake operation member is substantially performed. When released, the wheel cylinder communicates with the atmospheric pressure chamber via the pressurizing chamber of the master cylinder, while in other cases, the wheel cylinder may be a pilot open / close valve that shuts off the wheel cylinder from the master cylinder and the atmospheric pressure chamber. it can.

In another aspect, the valve cylinder has the valve element, and when the pilot pressure is substantially zero, the wheel cylinder is directly connected to the atmospheric pressure chamber. In other states, the wheel cylinder is connected to the atmospheric pressure chamber. It can be a pilot-type on-off valve that shuts off the valve.

The gist of the invention of claim 2 is that the invention of claim 1
Manual and electric dual brake system
In addition, it includes a reservoir for storing brake fluid at atmospheric pressure,
And the master cylinder is a brake housed in the pressurized chamber.
The pressurizing chamber is formed by pressurizing the liquid with a pressurizing piston.
To generate hydraulic pressure at the
When the ton is at the retracted end position, the pressurizing chamber is connected to the reservoir.
And a pilot operated on-off valve
However, the spool is fitted to the housing in a liquid-tight and slidable manner.
As a result, a liquid chamber is formed behind the spool.
And the fluid chamber is connected to the reservoir via the master cylinder.
When an annular groove is formed on the outer peripheral surface of the spool,
In both cases, the annular groove and the liquid chamber always communicate with each other.
A passage is formed in the spool and the spool is at the retracted end position.
The port communicating with the annular groove is
And a wheel cylinder is connected to that port.
It is in having done.

[0010]

In [act above constructed manual electric dual braking system as the wheel cylinder Pas
When the brake operating member is in a non-operating state, it is communicated with the atmospheric pressure chamber by the pilot-type on-off valve , whereas when the brake operating member is in the operating state, it is shut off from the atmospheric pressure chamber. In the non-operation state, the hydraulic pressure of the wheel cylinder is always equal to the atmospheric pressure.For example, even if the aforementioned failure occurs in the electric control hydraulic pressure source,
When the brake operation is released, the hydraulic pressure in the wheel cylinder is reliably eliminated.

[0011]

As described above, according to the present invention, if the brake operating member is in the non-operating state, the hydraulic pressure of the wheel cylinder is always set to 0, so that the reliability of the manual / electric dual brake system is improved. The effect is obtained.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a manual / electric dual system brake system for a four-wheeled vehicle according to an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a master cylinder, and reference numeral 11 denotes a reservoir for storing brake fluid at atmospheric pressure (this is one mode of the atmospheric pressure chamber in the present invention). A brake pedal 12 as a brake operation member is connected to the master cylinder 10. The master cylinder 10 is of a tandem type having two pressurizing pistons in series, and generates hydraulic pressures of almost the same height in two independent pressurizing chambers in response to depression of the brake pedal 12. The hydraulic pressure generated in one pressurizing chamber is applied to the main liquid passages 14, 16 and 18.
The hydraulic pressure generated in the other pressurizing chamber is transmitted to the wheel cylinders 30 of the left and right rear wheel brakes by the main fluid passages 24, 26 and 28. . Code 3
Numeral 2 is a caliper of a disk brake, and numeral 34 is a disk rotor. Since the front wheel brake system and the rear wheel brake system have the same configuration, the front wheel brake system will be representatively described below.

A pilot type hydraulic pressure source selection device (hereinafter simply referred to as a selection device) 4 is provided between the main liquid passages 14 and 16.
0 is connected. The selecting device 40 has a spool 42 fitted in a housing in a liquid-tight and slidable manner. Liquid chambers 44 and 46 are formed after and before the spool 42 (upper and lower in the figure). The liquid chamber 44 passes through the main liquid passage 14 and the master cylinder 10. It is connected to a wheel cylinder 20 via 18. An annular groove 50 is formed on the outer peripheral surface of the spool 42, and a communication passage 52 communicating with the liquid chamber 44 is opened in the annular groove 50. The spool 42 is always kept at the original position shown in the figure by the small elastic force of the spring 54, and the port 56 communicates with the liquid chamber 44 by the annular groove 50. When the pressure becomes higher than the liquid pressure in 46, the port advances (moves downward in the figure), and the port 56 is shut off from the liquid chamber 44 by the land 58 of the spool 42.

A liquid absorber 60 is connected to the port 56. The liquid absorber 60 is a spring type in which a piston 64, which is slidably and slidably fitted in the housing, is urged in a forward direction by a spring 66, and absorbs an amount of brake fluid proportional to the fluid pressure. Things. Also,
A normally open solenoid valve 70 is connected between the main liquid passages 16 and 18.

An electric control hydraulic pressure source 80 is connected to the main liquid passage 18. An electric control hydraulic pressure source 80 is provided in the housing.
This is an electric motor type in which a pressurizing piston 84 which is moved forward and backward by an electric motor 82 is fitted in a liquid-tight and slidable manner. A pressurizing chamber 86 is formed in front of the pressurizing piston 84, and the pressurizing chamber 86 is connected to the main liquid passage 18. A ball screw 88 is engaged with the rear end surface of the pressure piston 84. The ball screw 88 is held by a fixing member (not shown) so that the ball screw 88 cannot rotate around the axis and can move in the axial direction. The ball screw 88 is screwed to a nut 90. The nut 90 is held by a fixing member (not shown) so as to be rotatable around the axis and immovable in the axial direction. A large-diameter gear 92 is provided on the outer peripheral surface of the nut 90.
The small-diameter gear 94 is meshed with the large-diameter gear 92. The small-diameter gear 94 is connected to a rotation shaft of the electric motor 82 via a clutch 98. The clutch 98 is a one-way clutch that transmits the rotation of the electric motor 82 to the small-diameter gear 94 but does not transmit the rotation of the small-diameter gear 94 to the electric motor 82.

The electric control hydraulic pressure source 8 configured as described above
0, when the electric motor 82 is rotated in the forward direction, the small-diameter gear 94, the large-diameter gear 92 and the
The slot 90 is also rotated in the forward direction.
8 moves forward (moves rightward in the figure) integrally with the pressurizing piston 84, whereby the volume of the pressurizing chamber 86 decreases and the liquid pressure in the pressurizing chamber 86 increases. On the other hand, if the electric motor 82 is rotated in the reverse direction, the small-diameter gear
Gear 94, large diameter gear 92 and nut 90 also rotate in the opposite direction.
As a result, the ball screw 88 retracts integrally with the pressurizing piston 84, whereby the volume of the pressurizing chamber 86 increases and the fluid pressure in the pressurizing chamber 86 decreases. The electric motor 8
When 2 is in the stopped state, the hydraulic pressure in the pressurizing chamber 86 is maintained by the clutch 98.

A pilot type on-off valve 100 ( hereinafter simply referred to as on-off valve 100) is provided between the main liquid passages 14 and 16.
U. ) Are connected bypassing the selection device 40.
The on-off valve 100 has a spool 102 fitted in a housing in a liquid-tight and slidable manner. A liquid chamber 104 is formed after the spool 102 (upper side in the figure).
The liquid chamber 104 includes the main liquid passage 14 and the master cylinder 1.
0 is connected to the reservoir 11. Spool 10
2 has an annular groove 110 formed on the outer peripheral surface thereof.
10, a communication passage 112 communicating with the liquid chamber 104 is opened. The spool 102 always has a spring 114
Is kept in the original position as shown by the small elastic force of
Although the port 116 communicates with the liquid chamber 104 by the annular groove 110, when the liquid pressure in the liquid chamber 104, that is, the liquid pressure of the master cylinder 10 is higher than 0, the port 116 moves forward (moves downward in the figure) and the spool Port 116 is blocked from liquid chamber 104 by land 118 of 102. That is, the on-off valve 100 is connected to the hydraulic pressure in the liquid chamber 104 (the master cylinder 1).
(Equivalent to 0 hydraulic pressure) acts as a pilot pressure on the spool 102 as a valve.

The pedaling force applied to the brake pedal 12 is detected by a pedaling force sensor 130, and the wheel speed of each wheel is detected by each wheel speed sensor 132. Output signals from the sensors 130 and 132 are electronic control units (hereinafter simply referred to as ECUs; the same applies to the drawings) 1.
The ECU 140 controls the electromagnetic on-off valve 70 and the electric motor 82 based on the output signals. The ECU 140 includes a CPU, ROM, and R (not shown).
The AM is mainly composed of computers connected to each other by a bus. The program memory of the ROM always has a deceleration of a magnitude corresponding to the treading force, irrespective of the magnitude of the friction coefficient of the brake friction material of the disc brake, the magnitude of the inclination of the road surface, the magnitude of the loaded load, and the like. Various control programs are stored, including a control program that performs control that can be referred to as a braking effect control to be applied to the vehicle body, and a control program that performs anti-lock control that prevents the occurrence of excessive slip on each wheel during vehicle braking. I have. The ROM also stores an FG map that defines the correspondence between the pedaling force F and the deceleration G.

Next, the operation will be described. Brake pedal 12
Is not depressed, the selector 40, the liquid absorber 60, the electromagnetic on-off valve 70, the electric control hydraulic pressure source 80, and the on-off valve 100 are in the original state shown in the figure.

When the brake pedal 12 is depressed from this state, the hydraulic pressure of the master cylinder 10 increases. Therefore, the spool 102 of the on-off valve 100 is
The main liquid passage 16, the wheel cylinders 20, 30, and the pressurizing chamber 86 are shut off from the master cylinder 10 and the reservoir 11 by moving forward (moving downward in the drawing) against the elastic force of 4.

On the other hand, the ECU 140 reads the treading force from the treading force sensor 130, determines a target deceleration corresponding to the treading force by using the FG map, and actually outputs the target deceleration to the vehicle body based on the output signal of each wheel speed sensor 132. Is calculated. Further, the ECU 140 determines whether or not the electric motor 82 is based on the actual deceleration and the target deceleration.
Are calculated for the front wheel brake system and the rear wheel brake system, respectively.
Control. In the present brake system, when the electric control hydraulic pressure source 80 operates normally, the hydraulic pressure generated in the pressurizing chamber 86 is higher than the hydraulic pressure generated in the master cylinder 10 except for the state in which the antilock control is performed. It is set to be always higher. Therefore, assuming that the electric control hydraulic pressure source 80 is in a state of normal operation, if the brake pedal 12 is depressed, the selection device 40
Since the liquid pressure in the liquid chamber 46 is higher than the liquid pressure in the liquid chamber 44, the spool 42 is still kept at the original position shown in the drawing, and the master cylinder 10 is communicated with the liquid absorber 60, and 10 hydraulic pressure to wheel cylinder 2
0, 30, that is, a state in which the hydraulic pressure of the wheel cylinders 20, 30 is controlled by the electric control hydraulic pressure source 80. Therefore, this time, a hydraulic pressure having a height equal to the hydraulic pressure of each of the electric control hydraulic pressure sources 80 is generated in each of the wheel cylinders 20, 30, and the vehicle is braked at a deceleration corresponding to the pedaling force.

At present, the master cylinder 10 is
As a result, the brake fluid discharged from the master cylinder 10 as the depression of the brake pedal 12 is increased is absorbed into the liquid absorber 60, and the depression is reduced. As a result, the brake fluid in the fluid absorber 60 is returned to the master cylinder 10. Therefore, even when the hydraulic pressures of the wheel cylinders 20 and 30 are electrically controlled, an appropriate depression stroke is obtained according to the depression force, and the brake operation feeling is improved. The brake operation can be performed with the feeling that the hydraulic pressure of the wheel cylinders 20 and 30 is generated by the master cylinder 10.

During the braking operation, the ECU 140 also uses the output signals of the respective wheel speed sensors 132 to determine whether the pedaling force currently applied to the brake pedal 12 is too large in relation to the road surface friction coefficient, so that the front and rear wheels are It is periodically determined whether or not a lock tendency has occurred. If it is determined that the locking tendency has occurred, the braking effect control is interrupted and anti-lock control is started for the front wheel brake system and the rear wheel braking system to which the wheel determined to have the locking tendency belongs. .

Prior to the antilock control, the ECU 140
Closes the solenoid on-off valve 70 belonging to the brake system including the wheel that has determined that the locking tendency has occurred.
Wheel cylinders 20, 30 and electric control hydraulic pressure source 80
And selection device 40, master cylinder 10 and on-off valve 10
0 are blocked from each other. After that, the ECU 140 controls the electric motor 82 of the electric control hydraulic pressure source 80 so that the hydraulic pressure of the height that maintains the slip ratio of the wheel determined to have the locking tendency in the appropriate range is generated in the wheel cylinders 20 and 30. I do. During the antilock control, the electric control hydraulic pressure source 8
Although the hydraulic pressure of 0 may be reduced to a level lower than the hydraulic pressure of the master cylinder 10, the wheel cylinders 20 and 30 are shut off from the selection device 40 by the electromagnetic on-off valve 70, and thus the spool 42 of the selection device 40 Is kept in place.
Thereafter, if the ECU 140 determines that it is no longer necessary to perform the antilock control, the ECU 140 terminates the antilock control, opens the electromagnetic on-off valve 70, and restarts the braking effect control.

The case where the electric control hydraulic pressure source 80 operates normally has been described above. The case where the electric control hydraulic pressure source 80 has a failure in which the hydraulic pressure does not rise at all will be described.

In this case, even if the brake pedal 12 is depressed and the hydraulic pressure of the master cylinder 10 increases, the hydraulic pressure of the electric control hydraulic pressure source 80 does not increase. Therefore, when the fluid pressure in the fluid chamber 44 of the selection device 40 rises and the elastic force of the spring 54 is overcome, the spool 42 discharges the brake fluid in the fluid chamber 46 to the wheel cylinders 20 and 30 while returning to the original position. , Whereby the master cylinder 10 is shut off from the liquid absorber 60. Therefore, this time, the brake fluid in the master cylinder 10 is
It is discharged only to 0 and 30 and not discharged to the liquid absorber 60. As a result, the stepping stroke is prevented from being abnormally long in relation to the stepping force, and a good brake operation feeling is secured.

Pressurizing piston 84 of electric control hydraulic pressure source 80
When the electric control system (for example, the electric motor 82, a means for supplying an electric signal to the electric motor 82, etc.) is out of order, the retraction for increasing the volume of the pressurizing chamber 86 is not caused by the clutch 9
8, the pressurizing chamber 86 is in a state where the pressure can be increased. Therefore, in this state, the spool 42 of the selection device 40 can function as a mere partition that can move, and the liquid pressures having substantially the same height as the liquid pressure of the master cylinder 10 are applied to the liquid chambers 44 and 46 and the pressurizing chamber 86. And in the wheel cylinders 20 and 30. Therefore, even when the electric control hydraulic pressure source 80 fails, the vehicle can be braked without any trouble.

Next, when the brake pedal 12 is depressed,
That is, the pressurizing piston 84 of the electric control hydraulic pressure source 80 is advanced from the original position to shift from the state in which the hydraulic pressure is generated in the wheel cylinders 20 and 30 to the non-stepping state. A case where a failure of locking and not retreating occurs in the electric control hydraulic pressure source 80 will be described.

In this case, when the depression of the brake pedal 12 is released, the brake fluid in the fluid absorber 60 is returned to the master cylinder 10 and the pressurizing piston thereof retreats, so that the pressurizing chamber of the master cylinder 10 is released. The hydraulic pressure of the master cylinder 10 is reduced to zero by being connected to the reservoir 11. Therefore, the spool 102 of the on-off valve 100
The wheel cylinders 20, 30 are retracted (moved upward in the figure) by the elastic force of
The fluid pressure of the wheel cylinders 20 and 30 is reduced to zero through the reservoir 11. That is, in the present embodiment, the pressurizing piston 84 keeps the wheel cylinders 20 and 30 despite the brake operation being released.
If the brake pedal 12 returns to the non-depressed state, the on-off valve 100 is opened and the wheel cylinders 20 and 30 can be opened without the selection device 40 even if a failure occurs in which the hydraulic pressure is not reduced.
Is communicated to the reservoir 11 via the master cylinder 10, so that it is possible to prevent the wheel cylinders 20, 30 from continuously generating hydraulic pressure, that is, to prevent the wheel brakes from being kept effective.

FIG. 2 shows another on-off valve 160. The on-off valve 160 has a cylindrical housing 162 with a bottom. A plug 170 is fixed to the open end of the housing 162 in a liquid-tight manner by screwing. Reference numeral 172 is an O-ring and 174 is a backup ring. The housing 162 and the plug 170 have a stepped cylinder bore 17.
6 on which a stepped control piston 1 is formed.
78 are fitted in a liquid-tight and slidable manner. The space inside the housing 162 is partitioned into three by a control piston 178. The space behind the control piston 178 (upper space in the figure) is a liquid chamber 180, and the space in front of the control piston 178 (lower space in the figure) is liquid. An annular space between the chamber 182 and the stepped portion of the control piston 178 and the stepped portion of the cylinder bore 176 is a liquid chamber 184. The liquid chamber 180 is connected to the wheel cylinders 20 and 30 via the port 186 and the main liquid passage 16, and the liquid chambers 182 and 184 are connected to the master cylinder 10 via the ports 188 and 190 and the main liquid passage 14, respectively. I have. The liquid chambers 180 and 182 are always in communication with each other by a communication passage 192.

The control piston 178 includes a cup seal 19.
4, 196, 198 and 200 are mounted. Also, the control piston 178 is always
It is kept in the original position shown in the figure by two small elastic forces. Reference numeral 203 denotes an atmospheric pressure port which is always in communication with the reservoir 11.

An opening / closing valve 204 for opening and closing the port 188 is provided in the liquid chamber 182. On-off valve 204
Has a valve seat 206 formed on the inner surface of the bottom wall of the housing 162 and opening the port 188. On-off valve 20
4 further includes a rubber valve 216 that sits on the valve seat 206 and shuts off the port 188, and a direction perpendicular to the plane of the valve seat 206, that is, a direction parallel to the axial direction of the control piston 178. Holding member 2 slidably held on
20. The spring 202 is disposed between the holding member 220 and a spring retainer 222 on the control piston 178 side. A spring 224 that constantly biases the valve 216 toward the valve seat 206 is disposed between the holding member 220 and the valve 216.
6 is always separated from the valve seat 206 by the valve opening member 226.

Accordingly, in a state where the hydraulic pressure is not generated in the master cylinder 10 because the brake pedal 12 is not depressed, the control piston 178 is kept at the original position shown in the figure, and the open / close valve 204 is opened.
Reference numerals 0 and 30 communicate with the reservoir 11 via the liquid chamber 180, the communication passage 192, the liquid chamber 182, the on-off valve 204, and the pressurizing chamber of the master cylinder 10. From this state, the brake pedal 12 is depressed, and a hydraulic pressure is generated in the master cylinder 10, and a hydraulic pressure of the same height is generated in the liquid chamber 184, and the hydraulic pressure overcomes the elastic force of the spring 202. , The control piston 178 advances while compressing the spring 202 (moves downward in the figure). At this time, the valve element 216 advances integrally with the control piston 178 by the spring 224, and the valve seat 2
Sitting at 06. As a result, the port 188 is shut off, and the wheel cylinders 20 and 30 are connected to the master cylinder 10.
Be cut off from. That is, the on-off valve 160 is connected to the liquid chamber 18.
This is a type in which the valve 216 operates using the hydraulic pressure in the nozzle 4 (equal to the hydraulic pressure of the master cylinder 10) as the pilot pressure.

Although the two embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented in other embodiments.

For example, in any of the embodiments described above, the electric control hydraulic pressure source 80 controls the hydraulic pressure of the wheel cylinders 20 and 30 so as to generate a deceleration having a magnitude corresponding to the depression force applied to the brake pedal 12. Although the pressure is controlled, the hydraulic pressure of the wheel cylinders 20 and 30 may be controlled so as to generate a braking force having a magnitude corresponding to the depression force applied to the brake pedal 12, for example. It is.

Further, in the above-described embodiment, the electric control hydraulic pressure source 80 is configured to generate the hydraulic pressure by the operation of the pressurizing piston 86 based on the rotation of the electric motor 82. Pressurizing piston 8 based on displacement
The hydraulic pressure may be generated by the operation of step 6 or the hydraulic pressure may be generated by controlling the hydraulic pressure stored in the accumulator by a pump to an appropriate height by an electromagnetic control valve.

In the above embodiment, the selection device 4
Although 0 is a pilot type, other types can be used. For example, (a) the depression force of the brake pedal 12 or the hydraulic pressure of the master cylinder 10 and the wheel cylinder 2
And (b) an electromagnetic directional control valve for selectively communicating the wheel cylinders 20, 30 with the master cylinder 10 and the electric control hydraulic pressure source 80, and When the hydraulic pressure of the wheel cylinders 20 and 30 is higher than the hydraulic pressure of the master cylinder 10, the electromagnetic direction is switched so that the wheel cylinders 20 and 30 are connected to the electric control hydraulic pressure source 80. It is possible to take the form of switching valves.

In addition to these, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a system diagram of a manual / electric dual system brake system according to one embodiment of the present invention, and a front sectional view of a pilot-type on-off valve.

FIG. 2 is a front sectional view of another pilot on-off valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Master cylinder 11 Reservoir 20 Wheel cylinder 30 Wheel cylinder 40 Hydraulic pressure source selection device 80 Electric control hydraulic pressure source 100 Pilot type on-off valve 160 Pilot type on-off valve

Claims (2)

(57) [Claims] 1. A master cylinder for generating a hydraulic pressure in accordance with an operation of a brake operating member, a wheel cylinder for operating a brake for suppressing rotation of a wheel, and a hydraulic pressure of a height based on a brake operation amount is electrically controlled. electrically controlled hydraulic pressure source for generating a hydraulic pressure source selector for selecting one of said electrical control hydraulic pressure source and said master cylinder as a fluid pressure source for the wheel cylinders, independently of the said electrical control hydraulic pressure source The master cylinder
Is operated by receiving the hydraulic pressure of
When the pilot pressure is substantially zero, the wheel
The cylinder communicates with an atmospheric pressure chamber that stores hydraulic fluid at atmospheric pressure
On the other hand, when the pilot pressure is not substantially zero,
Pilot type that shuts off the wheel cylinder from the atmospheric pressure chamber
Manual / electric dual brake system including on / off valve . 2. A reservoir for containing a hydraulic fluid at atmospheric pressure.
And the master cylinder is housed in a pressurizing chamber.
Pressurized hydraulic fluid by the pressurizing piston
It generates hydraulic pressure in the pressurized chamber and
When the pressurizing piston is at the retreat end position, the pressurizing chamber
Are communicated with the reservoir, and
The pilot-operated on-off valve has a spool liquid-tight housing.
And by being slidably fitted, the spool
A liquid chamber is formed at the rear, and the liquid chamber is
And connected to the reservoir through the spool.
An annular groove is formed on the outer peripheral surface of the
A communication passage that constantly communicates with the liquid chamber is provided by the spoon.
With the spool at the retracted end position.
A port communicating with the annular groove is formed in the housing.
And the wheel cylinder is connected to that port.
The manual / electric dual system shaker according to claim 1,
System.