JPH04334647A - Modulator for anti-skid brake control device - Google Patents

Abstract

PURPOSE:To perform positive pressure re-intensifying action during anti-skid brake control and positively prevent a second passage with an orifice from being closed even if the valve spool of a flow regulating valve is operated for some reason. CONSTITUTION:In a valve spool 6d, a ring recessed groove 6o is formed in the vertical specified region of a passage hole 6j. Even in case the valve spool 6d is set in the relative uppermost position in relation to a housing 6a as shown by a two-dot chain line so as to shield the passage 6j and a recessed part 6i i.e., a passage hole 6s, a master cylinder 1, an orifice 9 and a passage switching valve 5 are set always in the communicated state by the recessed groove 60. Accordingly, even when the valve spool 6d moves upward to its maximum in relation to the housing 6a, braking liquid from the master cylinder 1 is positively fed to a brake cylinder.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modulator for an anti-skid brake control device for adjusting brake fluid pressure during anti-skid brake control in a vehicle.

0002

2. Description of the Related Art Generally, an anti-skid brake control device mounted on an automobile has the following features as shown in FIG.
A flow path switching valve 5 and a flow rate adjustment valve 6 located upstream of the flow path switching valve 5 are provided in a supply passage 4 that communicates the master cylinder 1 with the brake cylinder 3 of the wheel 2 . These flow path switching valves 5 and flow rate regulating valves 6 are similarly provided in supply passages to brake cylinders of other wheels.

During normal service brake operation, there is almost no pressure difference between the upstream side of the flow rate adjustment valve 6 and the downstream side of the flow path switching valve 5, so the flow rate adjustment valve 6 is maintained in the state shown. In this state, the brake fluid from the master cylinder 1 is mainly supplied to the brake cylinder 3 via the first passage 7, so the flow rate of the brake fluid is not restricted by the orifice 9 of the second passage 8. Therefore, the brake fluid pressure within the brake cylinder 3 increases rapidly in response to depression of the brake pedal.

During brake operation, an electronic control device (not shown) switches the flow path switching valve 5 if it determines that the wheels 2 are in a skid state. As a result, the brake fluid in the brake cylinder 3 passes through the decompression passage 10 to the sump device 11.
The hydraulic pressure inside the brake cylinder 3 decreases. Therefore, a pressure difference is generated between the supply passage on the upstream side of the flow rate adjustment valve 6 and the supply passage on the downstream side of the flow path switching valve 5. When this pressure difference exceeds a predetermined value, the first passage 7 of the flow rate regulating valve 6 is closed due to the pressure difference. Therefore, the flow rate regulating valve 6 is communicated only through the second passage 8 having the orifice 9.

On the other hand, since it is determined that the wheels 2 are in a skid state, the electronic control device drives the pump 12. Therefore, the pump 12 sends the brake fluid in the sump device 11 to the volume chamber 13 and to the master cylinder 1 .

In this state, when the electronic control device determines that the skid condition of the wheels 2 has been resolved, it switches the flow path switching valve 5, so that the brake cylinder 3 and the master cylinder 1
communicate with each other via the second passage 8. Therefore, the brake fluid in the master cylinder 1 and the brake fluid returned from the pump 12 are supplied to the brake cylinder 3 through the second passage 8 of the flow rate regulating valve 6. In that case, the flow rate of the brake fluid is restricted by the orifice 9 of the second passage 8, so the fluid pressure in the brake cylinder 3 gradually increases.

[0007] The flow path switching valve 5, the flow rate adjustment valve 6, the sump device 11, the pump 12, and the volume chamber 13 constitute a modulator 14 in the anti-skid brake control system. As described above, the electronic control device controls the flow path switching valve 5, the flow rate adjustment valve 6, and the pump 12 in the modulator 14, thereby performing anti-skid brake control for the wheels 2.

[0008]

[Problems to be Solved by the Invention] However, in such a conventional modulator, a predetermined pressure difference between the supply passage upstream of the flow rate adjustment valve 6 and the supply passage downstream of the flow path switching valve 5 is Therefore, even if the pressure difference exceeds a predetermined value during normal service brake operation other than during anti-skid brake control, the on-off valve 15 in the flow rate adjustment valve 6 will close the first passage 7. is possible.

[0009] Therefore, the applicant of the present invention has developed an anti-skid brake system in which the on-off valve 15 is switched and operated based on the difference between the discharge pressure of the pump 12 and the brake pressure of the brake cylinder 3, which are activated only during anti-skid brake control. We have developed a small modulator for an anti-skid brake control device that closes the first passage 7 only during control, and have applied for a patent (Japanese Patent Application No. 2-234134).

As shown in FIG. 3, this modulator 14
, the flow path switching valve 5 is switched during anti-skid brake control, so that the brake fluid in the brake cylinder 3 passes through the pressure reducing passage 10 to the sump device 1.
1 and the brake cylinder 3 is depressurized. When the pressure difference between the pump discharge pressure acting on the lower end of the valve spool 6d of the flow rate regulating valve 6 and the brake cylinder pressure acting on the upper end of the valve spool 6d exceeds a predetermined value, the valve spool 6d moves upward. As a result, the on-off valve 15 constituted by the land 5s and the land 6n closes to cut off direct communication between the passage hole 5q and the passage groove 22. Therefore, the brake fluid in the master cylinder 1 flows toward the flow path switching valve 5 through the second passage where the orifice 9 is located. As a result, when the flow path switching valve 5 is switched to the original normal position when the pressure of the brake cylinder 3 is increased again, the flow rate of the brake fluid is throttled by the orifice 9 and flows to the brake cylinder 3, and the brake cylinder 3 slowly Re-pressurized. In this way, anti-skid brake control is performed.

As described above, according to the modulator 14 of the invention of this application, the on-off valve 15 in the flow rate adjustment valve 6 opens the first passage (corresponding to the first passage 7 shown in FIG. 4) only during anti-skid brake control. Therefore, the on-off valve 15 does not close the first passage during normal service brake operation.

By the way, in the modulator 14 of this application, when the valve spool 6d moves up to the maximum relative to the housing 5a, it not only closes the first passage but also closes the second passage where the orifice 9 is located (see FIG. 4) may also be closed. That is, when the valve spool 6d is set at the relative uppermost position, the land 5s closes the passage hole 6j and the passage hole 5q
It is conceivable that the passage hole 6j and the passage hole 6j may be blocked.

When the passage hole 5q and the passage hole 6j are cut off in this way, the master cylinder 1 and the flow path switching valve 5 are cut off, so when the pressure is increased again during anti-skid brake control, the brake is removed from the master cylinder 1. There is a problem in that brake fluid cannot be supplied to the cylinder 3 and the pressure in the brake cylinder 3 cannot be increased again. Further, since the brake fluid pressure control device is an important component for safety in an automobile, it is still desirable to consider the case where the on-off valve 15 closes the first passage during normal service brake operation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a modulator for an anti-skid brake control device that can reliably increase pressure in a brake cylinder during anti-skid brake control. The goal is to provide the following. Another object of the present invention is to
Even if the valve spool of the flow rate adjustment valve operates for some reason during normal service braking, the second valve with the orifice
An object of the present invention is to provide a modulator for an anti-skid brake control device that can reliably prevent passages from being blocked.

[0015]

[Means for Solving the Problem] In order to solve the above-mentioned problem, the invention of claim 1 provides a supply passage that communicates a master cylinder and a brake cylinder, and is activated by the skid state of a wheel during braking. a flow path switching valve that releases the brake fluid supplied to the brake cylinder to the sump device; a pump that operates during anti-skid brake control to forcefully return the brake fluid stored in the sump device to the master cylinder; A first passage that is disposed in the supply passage upstream of the passage switching valve and does not restrict the flow of brake fluid to the passage switching valve, and a first passage that restricts the flow of brake fluid to the passage switching valve with an orifice. A modulator for an anti-skid brake control device comprising at least a flow rate adjustment valve having two passages, wherein the flow rate adjustment valve is slidably fitted into the flow rate adjustment valve housing and is inserted into a hole bored therein. The valve spool has a valve spool that accommodates the orifice, and the valve spool normally opens the first passage and directly communicates the master cylinder with the flow path switching valve, and the pressure difference between both ends of the valve spool is a predetermined value. is set to close the first passage and communicate the master cylinder with the flow path switching valve only through the second passage by sliding relative to the flow rate regulating valve housing when the flow rate adjustment valve housing exceeds Further, the valve spool is configured to maintain the second passage in a constant state of communication even when the valve spool is maximally slid relative to the flow rate regulating valve housing in the direction of blocking the first passage. The present invention is characterized in that a second passage blocking prevention means is provided.

[0016] Furthermore, the invention according to claim 2 is characterized in that the second passage comprises:
The second passage has at least a housing-side passage hole formed in the flow rate adjustment valve housing and always communicates with the master cylinder, and a valve spool-side passage hole formed in the valve spool and always communicates with the orifice, and the second passage is closed. The prevention means is characterized in that it is a groove formed on the outer peripheral surface of the valve spool so as to constantly communicate the housing-side passage hole and the valve spool-side passage hole.

Furthermore, the invention according to claim 3 is such that the brake fluid pressure of the brake cylinder acts on one end of the valve spool in a direction to open the first passage, and the pump discharge pressure acts on the other end of the valve spool. It is characterized in that it is set to act in a direction to close the first passage.

[0018]

[Operation] In the anti-skid brake control device modulator of the present invention having such a configuration, the second passage blocking prevention means provided on the valve spool of the flow rate regulating valve prevents the valve spool from moving against the flow rate regulating valve housing. Even when there is maximum relative sliding in the direction of blocking the first passage, the second passage with the orifice is always set in a communicating state. This makes it possible to reliably increase the pressure in the brake cylinder during anti-skid brake control. Further, even if the valve spool slides relative to the maximum due to some reason during the service brake, the communication state of the second passage is reliably maintained, so that the service brake is reliably operated.

In addition, in the invention of claim 2, since the second passageway blockage prevention means is constituted by a groove formed on the outer periphery of the valve spool, the second passageway blockage prevention means can be easily formed. You will be able to do this.

Furthermore, in the invention of claim 3, since the valve spool is operated by the differential pressure between the pump discharge pressure and the brake cylinder pressure, in most cases the valve spool is operated only during anti-skid brake control. Become. Therefore, the service brake can be operated reliably and quickly.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cross-sectional view of an embodiment of a modulator for an anti-skid brake control device according to the present invention, and is a diagram schematically and partially showing a hydraulic circuit of the anti-skid brake control device. Note that the same components as in the conventional example described above are given the same reference numerals.
The explanation will be omitted.

As shown in FIG. 1, the flow path switching valve 5 of the anti-skid brake control device modulator 14 of this embodiment has a pair of valve seat members 5b and 5c in a housing 5a.
are provided with a spacer 5d in between, and these valve seat members 5b
, 5c, a ball valve 5e is disposed in the center hole of the spacer 5d. The space between the valve seat members 5b and 5c is connected to the brake cylinder 3 via a mesh filter 16. Further, the center hole of the upper valve seat member 5c is connected to the valve actuator 5.
The lower valve seat member 5b is connected to the sump device 11 via an appropriate number of arc-shaped passage grooves 5i formed in the axial direction on the outer circumferential surface of the valve g and a pressure reduction passage 10, and the center hole of the lower valve seat member 5b is connected to the housing 5a. It is connected to the master cylinder 1 through a bored central passage hole 5j, as will be described later. The ball valve 5e has a valve actuator 5 fitted into the center hole of the valve seat member 5b.
f and a valve actuator 5g fitted into the center hole of the valve seat member 5c.

During normal service braking, the valve actuator 5f is urged upward by the spring 17, so that the ball valve 5e is separated from the valve seat member 5b and is seated on the valve seat member 5c. Therefore, brake cylinder 3
communicates with the master cylinder 1 through an appropriate number of arcuate grooves 5h formed in the axial direction on the outer circumferential surface of the valve actuator 5f and a central passage hole 5j, and is isolated from the sump device 11. When the solenoid is energized during anti-skid control, the valve actuator 5g descends, so the ball valve 5e is moved toward the valve seat member 5.
c, and seats on the valve seat member 5b. Therefore, the brake cylinder 3 is disconnected from the master cylinder 1 and communicated with the sump device 11 through the passage groove 5i and the pressure reduction passage 10.

A downwardly opening cylinder hole 5k is bored in the lower part of the housing 5a of the flow path switching valve 5, and is coaxial with the center passage hole 5j.
It is blocked from the center passage hole 5j by. A housing 6a of a flow rate regulating valve 6 is fitted into the cylinder hole 5k in a fluid-tight and slidable manner by a seal member 6b. The housing 6a is also fluid-tightly and slidably fitted into a hole in the main body 14a of the modulator 14.

A valve spool 6d is slidably fitted into the center hole 6c of the housing 6a. housing 5
A chamber 18 is formed between the partition wall 5m and the upper ends of the housing 6a and the valve spool 6d, and this chamber 18 is always connected to the brake cylinder 3 through a passage hole 5n bored in the housing 5a. has been done. Therefore, the brake pressure of the brake cylinder 3 acts on the upper end of the housing 6a and the upper end of the valve spool 6d. On the other hand, the modulator main body 14a
A chamber 19 is formed between the lower end of the housing 6a and the lower end of the valve spool 6d, and this chamber 19 is always connected to the discharge side of the pump 12, and is directly connected to the master cylinder 1 by an O-ring 6p. communication is cut off. Therefore, the pump discharge pressure of the pump 12 acts on the lower end of the housing 6a and the lower end of the valve spool 6d. Therefore, when the pump discharge pressure becomes greater than the brake cylinder pressure by a predetermined value or more, the valve spool 6d is set to move upward. Further, a spring 20 is compressed between the lower end of the housing 6a and the modulator main body 14a in the chamber 19, and the housing 6a is always urged upward by this spring 20. It is in contact with 5m.

A valve seat 6e is formed on the inner peripheral surface of the center hole 6c in the lower part of the housing 6a, and a valve spool 6
A valve portion 6f that can come into contact with this valve seat 6e is provided on the lower outer circumferential surface of d.
is formed. The valve spool 6d is always urged downward by the urging force of the spring 21 compressed between the partition wall 5m and the upper end of the valve spool 6d, and the valve portion 6f is normally in contact with the valve seat 6e.

Furthermore, a hole 6g opening downward is bored in the center of the valve spool 6d, and an orifice 9 is provided in this hole 6g. The orifice 9 is made by using an appropriate number of plates (eight in the illustration) that have orifice holes at different positions so that the orifice holes do not overlap.
Plugs 6h are stacked at predetermined intervals to close hole 6g.
It is a multilayer orifice fixed in the axial direction.

Further, a passage groove 22 is formed between the inner circumferential surface of the center hole 6c of the housing 6a and the outer circumferential surface of the valve spool 6d, and a passage groove 22 is formed between the outer circumferential surface of both housings 5a, 6a and the main body 14a of the modulator 14. The inner peripheral surface 14 of the hole
A passage groove 23 is formed between the groove 23 and b. Further, the housing 5a is provided with a passage hole 5o that communicates with the passage groove 23 and the center passage hole 5j, and the housing 6a is provided with a passage hole 6q that communicates with the passage groove 22 and the passage groove 23. has been done.

Furthermore, the housing 6a is provided with a passage hole 6r that communicates the passage groove 22 with the master cylinder 1, and a recess 6i formed in the inner peripheral surface of the center hole 6c of the housing 6a with the master cylinder 1. Passage hole 6 communicating with
s is drilled. Further, the valve spool 6d and the plug 6h are provided with a passage hole 6j and a passage hole 6k, respectively, which communicate the recess 6i with the upstream side of the orifice 9.

As shown in detail in FIG. 2, an annular groove 6o is formed on the outer peripheral surface of the valve spool 6d in upper and lower regions including the opening of the passage hole 6j. The vertical width of the concave groove 6o is such that when the valve spool 6d is set at the uppermost position where the valve spool 6d moves up to the maximum relative to the housing 6a, as shown by the two-dot chain line, the passage 6j and the recess 6i, that is, the passage The size is set such that even if the passage 6j and the passage 6s are in a position where they are blocked, the passage 6j and the passage 6s can communicate with each other. Therefore, the master cylinder 1, the orifice 9, and the flow path switching valve 5 are set to be in continuous communication with each other by the groove 6o.

As a result, even if the valve spool 6d moves upward relative to the housing 6a to the maximum, the brake fluid from the master cylinder 1 can be reliably supplied to the brake cylinder 3 through the groove 6o, and the anti-skid brake It becomes possible to increase the pressure in the brake cylinder again during control. Furthermore, even if the valve spool 6d moves upward relative to the housing 6a for some reason during normal service braking and moves to a position where it blocks the passage groove 22 and the passage hole 6r, the flow from the master cylinder 1 will be reduced. Brake fluid is reliably supplied to the brake cylinder 3 via the orifice 9 and the flow path switching valve 5, so that normal service brakes can be reliably operated. In this way, the groove 6o constitutes the second passageway blockage prevention means of the present invention.

[0032] Also, this groove 6o is connected to the valve spool 6d.
By forming the flow regulating valve 6, the axial length of the flow regulating valve 6 does not become long, so that the flow regulating valve 6 can be formed compactly. Furthermore, the valve spool 6d has a passage hole 6 that communicates between the downstream side of the orifice 9 and the passage groove 22.
m is drilled.

The master cylinder 1 has a passage hole 6r, a passage groove 22, a passage hole 6q, and a passage groove 2 connected thereto.
3. It communicates with the flow path switching valve 5 through the passage hole 5o and the center passage hole 5j, bypassing the orifice 9, and the first passage (
(corresponding to the first passage 7 shown in FIG. 4). The master cylinder 1 also has a flow path through the passage hole 6s, the recess 6i, the passage hole 6j, the passage hole 6k, the orifice 9, the passage hole 6m, the passage hole 6q, the passage groove 23, the passage hole 5o, and the center passage hole 5j. It communicates with the switching valve 5, and these passage holes, recesses, and passage grooves constitute a second passage (corresponding to the second passage 8 shown in FIG. 4).

Normally, the valve spool 6d is connected to the spring 2.
1 and located at the lowest position shown in the figure, the valve portion 6f
is seated on the valve seat 6e. At this time, the passage hole 6r and the passage groove 22 communicate with each other, so that the first passage is opened. Further, when the valve spool 6d moves upward due to a pressure difference greater than a predetermined value between the discharge pressure of the pump 12 and the brake cylinder pressure during anti-skid brake control, the communication between the passage hole 6r and the passage groove 22 is cut off, and the first The passages are closed and only the second passage 8 with the orifice 9 is open. In addition, in FIG. 1, 26 is a check valve that prevents the brake fluid in the chamber 19 from flowing to the pump 12. Therefore, the passage between the chamber 19 and the check valve 26 communicating with the chamber 19 is in a sealed state.

In the modulator 14 of this embodiment configured as described above, the first passage 7 is in communication during normal service braking, so the brake fluid from the master cylinder 1 mainly passes through the first passage 7. The fluid flows to the flow path switching valve 5 and further flows to the brake cylinder 3 without being restricted in flow rate. Therefore, the brakes are quickly applied. By the way, during this normal service brake operation, the brake fluid sent to the brake cylinder 3 is also introduced into the chamber 18 through the passage hole 5n. therefore,
Brake cylinder pressure acts on the upper end of the housing 6a and the upper end of the valve spool 6d, but when this brake cylinder pressure becomes large enough to overcome the urging force of the spring 20, the housing 6a and the valve spool 6d It moves downward against the biasing force, and the pressure in the sealed chamber 19 increases.

When the wheels 2 are in a skid state, anti-skid brake control is performed. That is, the ball valve 5e of the flow path switching valve 5 is removed from the valve seat on the side of the valve seat member 5c and is seated on the valve seat on the side of the valve seat member 5b, so that the flow path switching valve 5 is switched. brake fluid is discharged to the sump device 11 through the passage groove 5i and the pressure reduction passage 10. As a result, the pressure in the brake cylinder 3 is reduced. In addition, the pump 12 is driven by the start of anti-skid brake control, and the brake fluid in the sump device 11 is pumped into the chamber 19.
will be introduced in Therefore, pump discharge pressure comes to act on the lower end of the housing 6a and the lower end of the valve spool 6d.

As the pressure in the brake cylinder 3 is reduced, the pressure in the chamber 18 is also reduced, and when the pressure difference between the pump discharge pressure in the chamber 19 and the brake cylinder pressure in the chamber 18 exceeds a predetermined value,
The housing 6a and the valve spool 6d move upward,
The housing 6a comes into contact with the partition wall 5m, and the valve spool 6d moves upward relative to the housing 6a. Therefore, the passage hole 6r and the passage groove 22 are cut off, so that the master cylinder 1 communicates with the flow path switching valve 5 only through the second passage. In that case, the housing 6a
Since the pressure in the chamber 19 is increased by the downward movement of the valve spool 6d, when the pressure in the brake cylinder 3 is reduced, the pressure difference between the pressure in the chamber 19 and the pressure in the chamber 18 is relatively quickly reached at a predetermined level for the valve spool 6d to operate. Becomes a value. Therefore, the valve spool 6d operates quickly and the passage hole 6r and the passage groove 22 are quickly shut off. This improves the responsiveness of the flow rate regulating valve 6. Further, at this time, since the valve portion 6f is separated from the valve seat 6e, the brake fluid discharged from the pump 12 is returned to the master cylinder 1 through the chamber 19, the recess 6i, and the passage hole 6s.

In this state, when it is determined that the rotation of the wheels 2 has recovered and the skid condition has been resolved, the flow path switching valve 5 is switched to the initial position. Therefore, the brake fluid from the master cylinder 1 including the brake fluid returned from the pump 12 is reintroduced into the brake cylinder 3 through the second passage 8 and the flow path switching valve 5, and the brake pressure is increased again. . In that case, the flow rate of the brake fluid is throttled by the orifice 9, so the brake pressure increases slowly. When the wheels 2 enter the skid state again, the flow path switching valve 5 is switched again and the pressure in the brake cylinder 3 is reduced as described above. Thereafter, anti-skid brake control is performed by repeating pressure increase and pressure reduction again.

The present invention also applies to a modulator in which the housing of the flow path switching valve 5 and the housing of the flow rate regulating valve 6 are integrally formed into one housing, such as the invention of the earlier application shown in FIG. Needless to say, the present invention can be applied to a conventional modulator as shown in FIG.

[0040]

Effects of the Invention As is clear from the above description, according to the modulator for an anti-skid brake control device of the present invention, the valve spool is maximally relative to the flow rate regulating valve housing in the direction of blocking the first passage. Even when the brake cylinder slides, the second passage having the orifice is always set in a communicating state, so that the pressure in the brake cylinder can be reliably increased during anti-skid brake control. Further, even if the valve spool slides relative to the maximum due to some reason during service braking, the communication state of the second passage can be reliably maintained. Therefore, the service brake can be operated reliably at all times.

Furthermore, by constructing the second passageway blockage prevention means by a groove formed on the outer periphery of the valve spool, the second passageway blockage prevention means can be easily formed. Moreover, by providing the groove on the valve spool side in this way, the flow rate regulating valve can be formed compactly.

Furthermore, according to the third aspect of the invention, since the valve spool is operated only during anti-skid brake control in most cases, the service brake can be operated reliably and quickly at all times.

[Brief explanation of the drawing]

FIG. 1 is a schematic brake hydraulic circuit diagram of an anti-skid brake control device incorporating an embodiment of a modulator for an anti-skid brake control device according to the present invention.

FIG. 2 is an enlarged view of the main parts of the modulator of this embodiment.

FIG. 3 is a diagram showing a modulator for an anti-skid brake control device according to a prior application.

FIG. 4 is a diagram showing an example of a conventional anti-skid control circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Master cylinder, 3... Brake cylinder, 4... Supply passage, 5... Flow path switching valve, 5a... Flow path switching valve housing, 6... Flow rate adjustment valve, 6a... Flow rate adjustment valve housing, 6
d... Valve spool, 6j... Passage hole, 6o... Concave groove, 6s
... Passage hole, 7... First passage, 8... Second passage, 9... Orifice, 11... Sump device, 12... Pump, 14... Modulator, 14a... Main body, 18... Chamber into which brake cylinder pressure is introduced, 19... A chamber into which pump discharge pressure is introduced, 20...
biasing spring

Claims (3)

[Claims] 1. A flow path switching valve that is provided in a supply path that communicates a master cylinder and a brake cylinder, and is activated when a wheel skids during braking to release brake fluid supplied to the brake cylinder to a sump device; a pump that operates during anti-skid brake control to force and recirculate the brake fluid stored in the sump device to the master cylinder; and a pump that is disposed in the supply passage upstream of the passage switching valve and that is arranged in the supply passage upstream of the passage switching valve. A modulator for an anti-skid brake control device, comprising at least a first passage that does not restrict the flow of brake fluid to the flow path switching valve and a flow rate adjustment valve that has a second passage that restricts the flow of brake fluid to the flow path switching valve with an orifice. , the flow rate adjustment valve has a valve spool that is slidably fitted into the flow rate adjustment valve housing and accommodates the orifice in a hole bored therein; 1
The master cylinder is directly connected to the flow path switching valve by opening a passage, and when the pressure difference between both ends of the valve spool exceeds a predetermined value, the master cylinder is slid relative to the flow rate regulating valve housing. The first passage is closed so that the master cylinder communicates with the flow path switching valve only through the second passage, and the valve spool is configured such that the valve spool is connected to the flow rate regulating valve housing. The anti-skid brake is further provided with a second passageway blockage prevention means that keeps the second passageway open even when there is maximum relative sliding in the direction of blocking the first passageway. Modulator for control equipment. 2. The second passage includes a housing side passage hole formed in the flow rate regulating valve housing and always communicating with the master cylinder, and a valve spool side passage hole formed in the valve spool and always communicating with the orifice. and wherein the second passageway blockage prevention means is a groove formed on the outer circumferential surface of the valve spool to constantly communicate the housing-side passage hole and the valve spool-side passage hole. 2. The modulator for an anti-skid brake control device according to item 1. 3. The brake fluid pressure of the brake cylinder acts on one end of the valve spool in a direction to open the first passage, and the pump discharge pressure acts on the other end of the valve spool to close the first passage. 3. The modulator for an anti-skid brake control device according to claim 1, wherein the modulator is configured to act in a direction.