JPH06227378A - Brake fluid pressure controller - Google Patents

Abstract

PURPOSE:To impart a driver of a fact that operation is in antiskid control from a pedal as preventing any unpleasantkickback from occurring by installing such a route as minutely interconnecting a pump interconnecting port and a master cylinder interconnecting port with a minute movement due to differential pressure at both sides of a spool. CONSTITUTION:A spool 31 is a little moved downward from a state of being balanced, and a groove 47 interconnects a first sub port 45 and a fourth sub port 46 together with each other. During antiskid control, a brake fluid to be discharged out of a pump 27 is put back to a master cylinder 2 only at a time when two solenoid normally closed valves 21, 22 are switched. In addition, since a very small amount of brake fluid flow out of this master cylinder 2 in time of selecting these valves 21, 22, a return value of a brake pedal 3 is large enough, whereby a minute kickback is produced in this brake pedal 3, so a fact that antiskid control is in operation is imparted to a driver from the brake pedal 3, thereby making the driver recognizable in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device for antiskid control used in a brake device of a vehicle or the like.

[0002]

2. Description of the Related Art Conventionally, as a brake fluid pressure control device for anti-skid control, which has been adopted in a vehicle brake device for the purpose of preventing a tire from falling into a locked state during braking, brake fluid is applied by inputting to a brake pedal. A master cylinder communication port that is provided between a master cylinder that generates pressure and a wheel cylinder that generates braking force by brake fluid pressure and that communicates with the master cylinder, a wheel cylinder communication port that communicates with the wheel cylinder, and a variable capacity A casing having a reservoir communication port that communicates with the reservoir via a normally closed valve and a pump communication port that communicates with the discharge side of a pump that inhales and discharges the brake fluid on the reservoir side; and a casing provided inside the casing and provided with a spring. When the master cylinder is energized and is stationary, The port communicates with the wheel cylinder communication port, and the normally closed valve opens to move against the biasing force of the spring due to the differential pressure generated on both sides, and the master balances the differential pressure and the biasing force of the spring. The cylinder communication port is closed, the wheel cylinder communication port and the reservoir communication port are communicated with each other, and the brake fluid returned by the pump is closed to the reservoir with the normally closed valve opened, and the normally closed valve is closed. In some cases, a flow valve having a spool that is supplied to the wheel cylinder in a closed state is provided.

This brake fluid pressure control device prevents the pulsation of pump discharge from propagating to the master cylinder (so-called pedal kickback) during anti-skid control by closing the master cylinder communication port when the spool moves. Is able to. But,
If the master cylinder is not affected by the discharge of the pump at all, the information that the anti-skid control is active is not transmitted to the driver via the brake pedal.Therefore, the spool of the flow valve is connected to the pump communication port when moving. The present applicant has filed an earlier application regarding a structure in which a minute groove for allowing minute communication between the master cylinder and the master cylinder communication port is provided and the discharge of the pump is slightly transmitted to the master cylinder side (Japanese Patent Application No. 4-48917). issue).

[0004]

Although the brake fluid pressure control device of the above-mentioned application can inform the driver that the anti-skid control operation is being performed from the pedal while preventing an uncomfortable kickback, the brake fluid pressure control device can be performed from the pump. Since the discharged brake fluid is constantly returned from the minute groove to the master cylinder, the return amount of the brake pedal is slightly increased, and there is room for further improvement in this respect.

Therefore, an object of the present invention is to prevent uncomfortable kickback while informing the driver that the pedal is in the anti-skid control operation, and to prevent the pedal return amount from increasing. A pressure control device is provided.

[0006]

In order to achieve the above object, a brake fluid pressure control device of the present invention is a master cylinder in which brake fluid pressure is generated by an input to a brake pedal, and a braking force by the brake fluid pressure. A master cylinder communication port, which communicates with the master cylinder, a wheel cylinder communication port which communicates with the wheel cylinder, and a reservoir communication port which communicates with a variable capacity reservoir via a normally closed valve. And a casing having a pump communication port that communicates with the discharge side of a pump that sucks and discharges the brake fluid on the reservoir side, and is provided inside the casing and is urged by a spring, and when the urged state is stationary, the master Connect the cylinder communication port and the wheel cylinder communication port to the front When the normally closed valve is opened, the differential pressure generated on both sides moves against the biasing force of the spring and balances the differential pressure and the biasing force of the spring to close the master cylinder communication port and the wheel. Brake fluid that connects the cylinder communication port and the reservoir communication port and is returned by a pump to the reservoir when the normally closed valve is open, and to the wheel cylinder when the normally closed valve is closed. A flow valve having a spool to be supplied is provided, and the casing and the spool are communicated with the master cylinder by a minute movement due to a differential pressure on both sides of the spool generated when the normally closed valve is switched from the balanced state to the closed state. A path for slightly communicating the port and the wheel cylinder communication port, and A path for through small communication between the said pump communicating ports master cylinder communication port a minute movement by both sides differential pressure of the spool caused during opening switch of the normally closed valve is characterized by being provided.

[0007]

According to the brake fluid pressure control apparatus of the present invention, the path provided in the casing and the spool allows the spool to make a slight movement due to the differential pressure on both sides generated when the normally closed valve is switched from the balanced state to the master cylinder communication port. Since the wheel cylinder communication port and the wheel cylinder communication port are slightly communicated with each other, the brake fluid flows from the master cylinder to the wheel cylinder only during this time, and the brake pedal is slightly depressed. Also, due to other paths provided on the casing and spool,
The spool communicates minutely with the master cylinder communication port due to the slight movement due to the differential pressure on both sides that occurs when the normally closed valve is switched from the balanced state to the open state, so that the brake fluid flows from the pump to the master cylinder only during this period, and the brake pedal Is returned slightly. Therefore, the brake fluid discharged from the pump is returned to the master cylinder only when the normally closed valve is switched open, and a small amount of brake fluid flows out from the master cylinder when the normally closed valve is switched closed. I won't.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brake fluid pressure control device according to an embodiment of the present invention will be described below with reference to FIGS. In addition, the upper and lower sides used in the following description are used for convenience sake.

In the figure, reference numeral 1 is a brake hydraulic pressure control device for anti-skid control, reference numeral 2 is connected to a brake pedal 3, and hydraulic pressure is generated in response to depression of the brake pedal 3, and the like, for example, a cross. Two hydraulic pressure generation chambers 2A, which are transmitted to the hydraulic control circuits A and B of the two piped systems
2B shows a tandem master cylinder with 2B. Since the hydraulic pressure control circuit B side has the same configuration as the hydraulic pressure control circuit A side, only the hydraulic pressure control circuit A side will be described.

The hydraulic pressure control circuit A is further divided into two branch systems connected to a front wheel cylinder 4a and a rear wheel cylinder 4b, which are hydraulic actuators such as a disc brake or a drum brake. There is. That is, the hydraulic pressure control circuit A, after exiting from the hydraulic pressure generation chamber 2A of the master cylinder 2, is provided with the paths 5 of the two branch systems.
It is divided into 6, and flow valves 7 and 8 are provided in the respective paths 5 and 6. Each of the flow valves 7 and 8 includes a casing 10 having a cylindrical cylinder portion 9 extending in the vertical direction and a plurality of ports provided outside the cylinder portion 9.

Here, the above-mentioned port is a first port (at a predetermined position) orthogonal to the axis of the cylinder portion 9 so as to communicate with the hydraulic pressure generating chamber 2A via the paths 5 and 6 of each branch system. Master cylinder communication port) 11, the first port 1
1, a second port (wheel cylinder communication port) 13, which is provided at a predetermined lower position and communicates with the wheel cylinders 4a and 4b via the paths 12a and 12b of the respective branch systems, and the lower end of the cylinder portion 9. The cylinder part 9
A third port (reservoir communication port) 14 provided along the axial direction of the fourth port, and a fourth port provided so as to face the first port 11 and offset downward by a predetermined amount with respect to the first port 11. It is a port (pump communication port) 15.

The second port 13 is the first port 1.
1. Upper port 1 provided parallel to the lower side of a predetermined amount of 1
6 and a middle port 17 provided on the lower side of the upper port 16 by a predetermined amount in parallel therewith and communicating with the upper port 16 on the outside.
And a lower port 18 which is provided below the middle port 17 by a predetermined amount in parallel therewith and which communicates with the upper port 16 and the middle port 17 on the outside.

The third port 14 of each flow valve 7, 8 is connected to a path 19, 20 of each branch system, and an electromagnetic normally closed valve (normally closed valve) 21 is provided on these paths 19, 20. , 22 are provided respectively. Then, the routes 19 and 20 merge to form the route 23, and the route 23
One reservoir 24 having a variable capacity is provided so as to be connected to. The fourth ports 15 of the flow valves 7 and 8 are connected to each other by a path 25, and a path 26 is connected between the path 25 and the path 23. A pump 27 is provided. Here, the pump 27 includes a pump main body 28 that performs suction and discharge, an intake valve 29 provided on the reservoir 24 side of the pump main body 28, and a discharge valve 30 provided on the side opposite to the reservoir 24 of the pump main body 28. The brake fluid on the reservoir 24 side is sucked and discharged to the path 25 side.

A cylindrical spool 31 is fitted in the cylinder portion 9 of the casing 10 of the flow valves 7 and 8 so as to be vertically slidable. This spool 3
1 is an upper hole 32 of a predetermined diameter provided in the center from the upper end to a predetermined intermediate position along the axial direction, and an upper hole 32 having the same diameter as the upper hole 32 from the lower end to a predetermined intermediate position, and is always provided. It has a lower hole 33 communicating with the third port 14, and the upper hole 32 and the lower hole 33 communicate with each other through a small diameter hole 34 having a smaller diameter than the above. The opening at the lower end of the lower hole 33 has a diameter larger than the other parts by a predetermined amount, and the spool 3 is inserted in this opening.
Spring 3 for urging 1 upward with a predetermined urging force
The upper end of 6 is inserted.

A plurality of holes are formed in the spool 31 at right angles to the upper hole 32 and the lower hole 33. These holes are provided on the lower side by a predetermined amount from the upper end of the spool 31, and are in a stationary state (the state shown in FIG. 1) in which the spool 31 is biased by the spring 36 and the upper end contacts the cylinder portion 9. Sometimes the upper hole 32 and the first port 11 are communicated with each other, and the spool 31 moves due to the differential pressure generated on both sides during anti-skid control, and when in the moving state, the first port 11 and the upper port 32 A first hole 37 for blocking the communication between the upper hole 32 and the upper port 16 of the second port 13 when the spool 31 is provided a predetermined amount below the first hole 37 and the spool 31 is in the stationary state, Further, the second hole 3 for blocking the communication between the upper hole 32 and the upper port 16 when the spool 31 is in the above-mentioned moving state.
8, the spool 3 provided a predetermined amount below the second hole 38
When 1 is in the stationary state, communication between the lower hole 33 and the middle port 17 and the lower port 18 of the second port 13 is blocked, and when the spool 31 is in the moving state, the lower hole 33 and the lower port 18 are connected. Third hole 3 for communicating with
9, and when the spool 31 provided facing the first hole 37 is in the stationary state, the communication between the upper hole 32 and the fourth port 15 is blocked, and when the spool 31 is in the moving state. The upper hole 32 and the fourth port 15 are communicated with each other, and when the spool 31 moves downward, the fourth hole 40 limits the communication (fine communication or block).

Here, for convenience, the first hole 37 and the fourth hole 40 are provided.
However, since there is an annular groove 41 on the outer circumference of the spool 31, there is no difference between the two and, of course, only one may be provided, and the second hole 38 and the third hole 39 may be provided. Similarly, on the outer periphery of the spool 31, annular grooves 42, 4 are formed.
3 are provided respectively. In addition, the lower hole 3 of the third hole 39
The part communicating with 3 is slightly larger in diameter than the small diameter hole 34.

In this embodiment, both flow valves 7 and 8 are provided with a casing 10 and a first port 11
A first sub-port 45 that branches off from the first port 11 on the inner circumference of the cylinder part 9 and opens at a predetermined position below the first port 11, and an opening of the first sub-port 45 that branches off from the fourth port 15 on the inner circumference of the cylinder part 9. A fourth sub-port 46 that opens at a predetermined position above the position is provided, and an annular groove 47 is provided on the outer periphery of the spool 31 at a predetermined position below the groove 41 and below the groove 47. An annular groove 48 is formed at a predetermined position on the side. Further, the groove 48 is the hole 4
9 communicates with the upper hole 32.

The grooves 47 and 48 do not open to any of the ports when the spool 31 is in the stationary state, the spool 31 is in the moving state, and the differential pressure between both sides and the urging force of the spring 36 are exerted. Is in a balanced state (the state shown in FIG. 3), only the groove 47 communicates with the fourth subport 46. Further, during the anti-skid control, the solenoid normally closed valves 21 and 22 are moved to shift to the re-pressurizing operation.
Is closed from the open state and the spool 31 is slightly moved upward from the balanced state due to the change in the differential pressure between the two sides, a minute time until the balance is re-balanced, as shown in FIG.
Slightly communicate with the first sub-port 45, and the first sub-port 45 communicates with the upper hole 32 through the hole 49. Further, during the anti-skid control, the electromagnetic normally closed valves 21 and 22 are opened from the closed state to shift to the depressurization operation, and the spool 31 is slightly moved downward from the balanced state due to the change in the differential pressure on both sides, until the balance is re-balanced. For a very short time, as shown in FIG. 4, the groove 47 slightly communicates with the first sub-port 45 and the fourth sub-port 46, respectively, and makes them communicate with each other.

The groove 48, the first sub-port 45, and the hole 49 are placed in a balanced state so that the electromagnetic normally closed valves 21 and 2 are closed.
A path for slightly communicating the first port 11 and the second port 13 at the time of closing switching of 2 is mainly configured, and the groove 47, the fourth sub-port 46, and the first sub-port 45 move from the balanced state to the electromagnetic normally closed valves 21, 22. A path for slightly communicating the fourth port 15 and the first port 11 at the time of switching the opening of is formed.

A path 51 is bypass-connected between the path 23 and the path 26, and the relief valve 5 is connected to the path 51.
Two are provided. This relief valve 52 is
Pump communication chamber 5 having a port 53 connected to the intake port and a port 54 communicating with the suction side of the pump 27 via the path 51
5 and a master cylinder communication chamber 56 provided in parallel with and separated from the pump communication chamber 55. The pump communication chamber 55 and the master cylinder communication chamber 56 are provided.
A communication hole 57 penetrates in between, and a cylindrical piston 58 is fitted in the communication hole 57 so as to be vertically movable by a predetermined amount.

Here, the port 53 is seated in the pump communication chamber 55 when the seat 59 is seated in the pump communication chamber 55.
Valve body 60 that closes the valve and moves upward when the brake fluid pressure from the port 53 becomes high to open the valve and allow the brake fluid to flow to the suction side of the pump 27 through the port 54. Is provided. Here, a spring 61 that urges the valve element 60 downward is in contact with the valve element 60, and a lower end of a piston 58 that is urged by the spring 62 is in contact with the valve element 60.

A cup 63 is inserted below the master cylinder communication chamber 56.
The path 6 on the hydraulic pressure generating chamber 2A side is connected to the port 64 provided on the upper side of the path via the path 65. When the pressure on the master cylinder communication chamber 56 side is higher than the pressure on the pump communication chamber 55 side, the cup 63 blocks the mutual communication, and the pressure on the master cylinder communication chamber 56 side is higher than the pressure on the pump communication chamber 55 side. When the height is low, these are made to communicate with each other through the gap between the communication hole 57 and the piston 58. The valve opening pressure of the valve body 60 is higher than the pressure of the hydraulic pressure generating chamber 2A, which is introduced from the path 56 and is applied to the piston 58, by a predetermined biasing force of the springs 61 and 62.

Next, the operation of the brake fluid pressure control apparatus 1 of the present embodiment having the above-mentioned configuration will be described step by step with reference to an example of the operation shown in FIG. Here, FIG.
FIG. 5A shows the change of the stroke amount of the master cylinder (the depression amount of the brake pedal) with respect to time, and FIG.
FIG. 5C shows a change in the brake fluid pressure of the wheel cylinder with respect to time, and FIG. 5C shows a downward displacement amount of the spool with respect to time. Further, the alternate long and short dash line shown in FIG. 5 (a) indicates a type in which the first port is completely blocked during anti-skid control, and the broken line indicates a type in which the first port is not blocked during anti-skid control. There is.

First, as shown in FIG. 1, the stationary spool 31 of the flow valves 7 and 8 in the non-operating state of the anti-skid control has the first port 11, the first hole 37, the upper hole 32, and the second hole. 38 and upper port 1 of the second port 13
The hydraulic pressure generating chamber 2A and the wheel cylinders 4a and 4b of the same branch system are communicated with each other via 6 to pressurize the wheel cylinders 4a and 4b in a normal operation, that is, according to the depression of the brake pedal 3 or the like. (Time 0 to t ₁ in FIG. 5). Here, at this time, each third hole 39
The fourth hole 40 is in a state in which communication with any of the ports on the outer peripheral side is blocked, and the grooves 47 and 48 are
It does not open to any port.

When a controller (not shown) determines that the anti-skid control is started based on the information from the wheels and the wheel cylinders 4a and 4b are depressurized by the anti-skid control, the electromagnetic normally closed valves 21 and 22 are opened. As a result, the brake fluid in the portion surrounded by the lower hole 33 and the lower portion of the casing 10 flows into the reservoir 24, and the differential pressure on both sides of the spool 31 (the upper hole 32 side and the lower hole 33 side) is thereby generated. Then, the spool 31 moves downward to block the communication between the first port 11 and the first hole 37, and the wheel cylinders 4a and 4b and the reservoir 24 are connected to the middle port 17 and the lower port 18 of the second port 13. And the third hole 39 and the lower hole 33 are communicated with each other to allow the brake fluid in the wheel cylinders 4a and 4b to flow into the reservoir 24, and the wheel cylinder Da 4a, has a brake fluid pressure 4b so as to vacuum (between t ₁ ~t ₃ in FIG. 5).

Here, the pump 27 is always driven during the anti-skid control, and the fourth port 15 of the casing 10 of the flow valve 8 during the depressurization.
And the fourth hole 40 of the spool 31 are in communication with each other, and the reservoir 24 sucked and discharged by the pump 27
The brake fluid in the master cylinder 2
The fluid is circulated to the reservoir 24 via the fourth port 15, the fourth hole 40, the upper hole 32, the small diameter hole 34, the lower hole 33 and the third port 14 while being maintained at a value higher than the hydraulic pressure on the side.

When the solenoid normally closed valves 21 and 22 are switched to open at the initial stage of the anti-skid control, the spool 31 suddenly decreases the hydraulic pressure on the side of the lower hole 33 of the small diameter hole 34. Strokes further downward (the position shown in FIG. 4) beyond the position (the position shown in FIG. 3) where the pressure difference between the pressure and the urging force of the spring 36 is balanced, and the decompression operation is continued to balance the pressure after a minute time. To do. As shown in FIG. 4, the groove 47 slightly communicates with the first sub-port 45 and the fourth sub-port 46, respectively, until the spool 31 is balanced until the spool 31 is balanced. The discharge side of the pump 27 and the master cylinder 2 are slightly communicated with each other through the fourth port 15, the fourth subport 46, the groove 47, the first subport 45, and the first port 11, so that the pump 27 and the master cylinder 2 communicate only during this period. 2 and the brake pedal 3 is slightly returned (from t _{1 to} t in FIG. 5).
Between ₂ ).

Then, as shown in FIG. 3, when the differential pressure on both sides of the spool 31 and the urging force of the spring 36 are balanced, the first port 11 and the first sub-port 4
No. 5 is in the closed state, and the pressure is reduced while the depression amount of the brake pedal is kept constant without changing (between t _{2 and} t ₃ in FIG. 5).

Next, when the controller determines that the wheels have been avoided from the lock tendency and re-pressurizes the brake fluid pressure of the wheel cylinders 4a, 4b, the electromagnetic normally closed valve 2
By closing the valves 1 and 22, the circulating brake fluid is supplied to the fourth port 15 of the flow valves 7 and 8, and the fourth hole 40, the upper hole 32, the small diameter hole 34, the lower hole 33, third hole 39, and the wheel cylinder 4a through the lower port 18 or the like of the second port 13, flow at a substantially constant flow rate 4b, so that the re-pressurizing this (between t ₃ ~t ₅ in FIG. 5) .

Here, when the electromagnetic normally closed valves 21, 22 are closed and switched, the hydraulic pressure on the lower hole 33 side of the small diameter hole 34 rises, so that a slight differential pressure change occurs on both sides of the spool 31.
After the spool 31 is slightly moved upward from the balanced state, re-pressurization is continued to rebalance after a lapse of a minute time. As shown in FIG. 2, the groove 48 is slightly communicated with the first sub-port 45 from the time of this closing switching until the spool 31 is balanced again.
Is communicated with the upper hole 32 through the hole 49, whereby the brake fluid from the master cylinder 2 flows through the first port 11, the first sub-port 45, the groove 48, the hole 49 and the like through the flow valves 7, 8. internal introduced into the wheel cylinders 4a, the brake pedal 3 flows to 4b are slightly stepping-on of (between t ₃ ~t ₄ in FIG. 5). Here, in the state of FIG. 2, the fourth port 15 communicates with the first sub-port 45 via the fourth hole 40, the upper hole 32, the hole portion 49 and the groove 48, but at this time, the lower side of the spool 31. The pressure in the chamber above the small diameter hole 34 of the spool 31 is lower than the discharge pressure of the pump 27 and the pressure of the master cylinder 2, and the above-mentioned flow is generated. Occurs.

Then, as shown in FIG. 3, when the differential pressure on both sides of the spool 31 and the urging force of the spring 36 are balanced, the first port 11 and the first sub-port 4 are connected.
5 becomes closed, re-pressurization is carried out while being kept constant without stepping-on and the return of the brake pedal 3 is changed (between t ₄ ~t ₅ in FIG. 5).

Further, when the electromagnetic normally closed valves 21 and 22 are opened to switch the anti-skid control to the depressurization operation from the above-mentioned balanced state in which the electromagnetic normally closed valves 21 and 22 are closed, the discharge pressure of the pump 27 as described above. Will circulate to the reservoir 24, but when the electromagnetic normally closed valves 21 and 22 are closed and switched, the spool 31 slightly moves downward from the balanced state and the groove 47 becomes the first sub-port 45, as described above. And the fourth sub-ports 46 are communicated with each other, and the brake fluid flows from the pump 27 to the master cylinder 2 only during this time, and the brake pedal 3 is slightly returned (t _{5 to} t in FIG. 5).
Between ₆ ). Then, the opening / closing operations of the electromagnetic normally closed valves 21 and 22 described above are appropriately repeated.

Therefore, during the anti-skid control, the brake fluid discharged from the pump 27 is released by the electromagnetic normally closed valves 21, 2.
The brake pedal 3 is returned to the master cylinder 2 only when the open switching of 2 is performed, and a small amount of brake fluid flows out from the master cylinder 2 when the electromagnetic normally closed valves 21 and 22 are closed.
A small amount of kickback is generated in the brake pedal 3 without increasing the return amount, and the driver can be informed by the brake pedal 3 that the antiskid control is in operation.

In the above embodiment, only one of the wheel cylinders 4a and 4b is in a state of performing anti-skid control, and the pump 27 is driven to drive one of the normally closed solenoid valves 21 and 22. Even when the opening / closing operation is performed, since the first port 11 is blocked by the movement of the spool 31 on the operating side of the anti-skid control, the influence of the discharge of the pump 27 on the master cylinder 2 side is caused at the time other than the above switching of the opening / closing. On the non-operating side of the anti-skid control, the spool 31 is stationary and the fourth port 15 is closed by the spool 31, so that the master cylinder 2 side is not affected by the discharge of the pump 27. There is nothing you can do.

[0035]

As described in detail above, according to the brake fluid pressure control apparatus of the present invention, the brake fluid discharged from the pump is returned to the master cylinder only during the switching of the normally closed valve during the anti-skid control. Also, since a small amount of brake fluid flows out from the master cylinder when the normally closed valve is closed, a slight kickback occurs on the brake pedal without increasing the pedal return amount, and the anti-skid control is operating from the brake pedal. That is, the driver can be informed and recognized.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing a brake fluid pressure control device according to an embodiment of the present invention, showing a state during normal braking.

FIG. 2 is a cross-sectional view showing a flow valve of the brake fluid pressure control device according to one embodiment of the present invention, showing a state in which the spool is located slightly above the balance state.

FIG. 3 is a cross-sectional view showing a flow valve of a brake fluid pressure control device according to an embodiment of the present invention, showing a balance state of spools.

FIG. 4 is a cross-sectional view showing a flow valve of a brake fluid pressure control device according to an embodiment of the present invention, showing a state in which a spool is located slightly below a balanced state.

FIG. 5 is a characteristic diagram showing an example operation of a brake fluid pressure control device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Brake Fluid Pressure Control Device 2 Master Cylinder 3 Brake Pedal 4a, 4b Wheel Cylinder 7, 8 Flow Valve 10 Casing 11 First Port (Master Cylinder Communication Port) 13 Second Port (Wheel Cylinder Communication Port) 14 Third Port (Reservoir) Communication port) 15 4th port (pump communication port) 21, 22 Electromagnetic normally closed valve (normally closed valve) 24 Reservoir 27 Pump 31 Spool 36 Spring

Claims (1)

[Claims] 1. A master cylinder communication port, which is provided between a master cylinder in which a brake fluid pressure is generated by an input to a brake pedal and a wheel cylinder in which a braking force is generated by the brake fluid pressure, and which communicates with the master cylinder. A wheel cylinder communication port that communicates with the wheel cylinder, a reservoir communication port that communicates with a variable volume reservoir via a normally closed valve, and a pump communication port that communicates with the discharge side of a pump that inhales and discharges the brake fluid on the reservoir side. And a casing provided inside the casing and urged by a spring so that the master cylinder communication port and the wheel cylinder communication port are communicated with each other when the urged stationary state is established, and the normally closed valve is opened. The differential pressure generated on both sides by The master cylinder communication port is closed by balancing the differential pressure and the urging force of the spring, and the wheel cylinder communication port and the reservoir communication port are communicated with each other. A brake fluid pressure control device comprising a flow valve having a spool for supplying the reservoir with the normally closed valve opened and to the wheel cylinder with the normally closed valve closed, wherein the casing and the spool Includes a path for causing the master cylinder communication port and the wheel cylinder communication port to communicate with each other by a slight movement due to a differential pressure on both sides of the spool that occurs when the normally closed valve is switched from the balanced state to the A slight difference due to the pressure difference between the two Brake fluid pressure control apparatus characterized by a path for through small communication between the said pump communicating port and the master cylinder communication port in the mobile is provided.