JPS6237260A - Anti-lock control device for car - Google Patents

Abstract

PURPOSE:To apply a braking force to a wheel brake via a bypass regardless of the operation of a modulator by providing a check valve opened to the bypass detouring the modulator by a predetermined value of the output oil pressure of a master cylinder on a brake oil passage. CONSTITUTION:An anti-lock control device 7 is mainly constituted with a hydraulic pump 16, a modulator 17, a discharge valve 20, and a sensor 21. A bypass 10 connecting an input oil pressure chamber 55 of the modulator 17 is provided, this bypass 100 detours the modulator 17 and connects upstream and downstream pipes 15a, 15b of a hydraulic conduit 15 together, and an orifice 101 and a check valve 102 are provided in series from the input oil pressure chamber 54 side in sequence. This check valve 102 is opened when the output oil pressure of a front master cylinder 5f exceeds a specified high-pressure value, thus a braking force is applied via the bypass even if the decompression state of the control oil pressure chamber 18 of the modulator 17 is continued.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to an anti-lock control device used to avoid locking of wheels during braking in vehicles such as motorcycles and automobiles; In particular, a hydraulic pump driven by the wheels during braking; a modulator having a control hydraulic chamber supplied with the discharge pressure of the hydraulic pump and interposed in the brake oil passage between the master cylinder and the wheel brake; the control hydraulic pressure; The modulator is composed of a normally closed exhaust pressure valve installed in a communication path between the chamber and the oil tank; and a sensor that opens the exhaust pressure valve when detecting that the wheel is about to become stuck. The present invention relates to an improvement in a device configured to control a brake oil passage in order to reduce the braking force of a wheel brake when the pressure in a control hydraulic chamber is reduced by opening a discharge pressure valve.

(2) Prior Art The anti-lock control device for a vehicle as described above is already known, as described in, for example, Japanese Patent Laid-Open No. 120440/1983.

(3) Problems to be Solved by the Invention Conventionally, in the above-mentioned anti-lock control device, if the exhaust pressure valve is left open due to some kind of failure, the pressure in the control hydraulic chamber of the modulator continues to be reduced, causing problems in braking. become.

The present invention has been made in view of the above circumstances, and even if the pressure in the control oil chamber of the modulator continues to be reduced due to a failure, if the output oil pressure of the master cylinder is increased to a specified high pressure value or higher, It is an object of the present invention to provide the above-mentioned anti-lock control device that can apply a desired braking force to a wheel brake.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention connects a binosu to bypass the modulator to the brake oil passage, and connects a master cylinder to the bypass. The valve is characterized by being equipped with a check valve that opens when the output oil pressure exceeds a specified high pressure value.

(2) Operation When the output oil pressure of the master cylinder is increased beyond the specified high pressure value, the check valve opens and the brake oil path becomes conductive via the bypass, so it is not affected by the operating state of the modulator. The output hydraulic pressure of the master cylinder can be transmitted to the wheel brakes without any problems.

(3) Examples Embodiments of the present invention will be described below with reference to the drawings.

First, in FIG. 1, the motorcycle 1 includes a pair of left and right front wheel brakes 3f, :M for braking the front wheel 2r, and one rear wheel brake 3r for braking the rear wheel 2r. Brake 3.

3f is operated by the output hydraulic pressure of the front master cylinder 5f operated by the brake lever 4, and the rear wheel brake 2r is operated by the output hydraulic pressure of the front master cylinder 5f operated by the brake pedal 6.
It is operated by the output hydraulic pressure of r, but especially the front wheel brake 3
The braking oil pressures f and 3f are controlled by an anti-lock control device 7.

Therefore, the front wheel 2r corresponds to the wheel of the present invention, and the front wheel brake 3f corresponds to the wheel brake of the present invention.

In FIGS. 2 and 3, the knob 8 of the front wheel 2f is supported on an axle lO fixed to the lower end of the front fork 9 via a bearing 11.11. A pair of front wheel brakes 3f, 3f disposed on both sides of the front wheel 2f each include a brake disc 12 fixed to the end surface of the hub 8,
The brake caliper 14 is supported by the front fork 9 via the bracket 13 while straddling the brake disc 12. When the brake caliper 14 is supplied with the output hydraulic pressure of the master cylinder 5r to its input port 14a, When activated, it can compress the brake disc 12 and apply braking force to the front wheel 2''.

An anti-lock control device 7 is interposed in a hydraulic conduit 15 serving as a braking oil path that connects the output port 1-5fa of the front master cylinder 5f and the input boat 14a of each brake caliper 14.

The anti-lock control device 7 includes a hydraulic pump 16 that is driven by the front wheel 2f during braking, and a control hydraulic chamber 18 into which the discharge pressure of the hydraulic pump 16 is introduced, and the hydraulic conduit 15.
A modulator 17 interposed between the control hydraulic pressure chamber 18 and the oil tank 19, a normally closed exhaust pressure valve 20 interposed in the communication path between the control hydraulic pressure chamber 18 and the oil tank 19, and the front wheel 2f detecting that the front wheel 2f is about to be locked. An inertial sensor 21 that opens the exhaust pressure valve 20
These are the main components of the casing 22.
composed of inside.

The casing 22 includes a cup-shaped housing 22a and this housing 2.
A lid body 22 that fits into the open end of 2a and is fixed with screws 23
b, the casing 22a is disposed so as to fit in a recess 8a formed on one end surface of the hub 8, and a lid 22b
is connected to the axle 10 via a cylindrical shaft 24 fixed at its center.
The front fork 9 is supported by the front fork 9 and connected to the front fork 9 by a rotation preventing means so as not to rotate around the axle 10.

The rotation preventing means is arbitrary, but for example, a bolt 25 for fixing the bracket 13 to the front fork 9
(See Figure 2) is appropriate.

The hydraulic pump 16 includes a camshaft 26 disposed parallel to the axle 10, a bushing rod 27 disposed with its inner end facing an eccentric cam 26a formed on the camshaft 26, and an outer shaft of the bushing rod 27. The working piston 29 rests on the outer end of the pump piston 28
and a return spring 30 that biases the bushing rod 27 in a direction away from the eccentric cam 26a.

The bushing rod 27 and the pump piston 28 are slidably fitted into a first cylinder hole 33 formed in the lid 22b so as to define an inlet chamber 31 and an outlet chamber 32 on their respective outer peripheries. Further, a plug body 34 is fitted into the outer end of the first cylinder hole 33 so as to define a pump chamber 35 between it and the pump piston 28, and a hydraulic chamber 36 is defined in the plug body 34. The actuating piston 29 is slidably engaged with the actuating piston 29 .

The inlet chamber 31 communicates with the oil sludge 19 via a conduit 37 and also communicates with a pump chamber 35 via a suction valve 38, and the pump chamber 35 communicates with the outlet chamber via a one-way seal member 39 having a discharge valve function. 32. Further, the hydraulic chamber 36 is connected to the upstream pipe 15a of the hydraulic conduit 15 so as to constantly communicate with the output pump 5fa of the front master cylinder 5[.

As shown in FIG. 4, the camshaft 26 is supported by the lid body 22b via hair rings 40 and 40', and the drive shaft 26 is rotatably supported on the cylindrical shaft 24 via a hair ring 4141. It is driven from the shaft 42 through a pair of gears 43 and 44, and the drive shaft 42 is driven from the front wheels 2f through a speed increasing gear device 45, which will be described later. As a result, the camshaft 26 is driven at an increased speed by the front wheel 2f.

A meter drive gear 49 is fixed to the outer end of the camshaft 26 opposite to the gear 44, and this gear 4 is meshed with a driven gear 50 connected to a human power shaft of a speedometer 51 of the motorcycle.

The modulator 17 includes a decompression piston 46, a fixed piston 47 that receives and stops one end of the decompression piston 46 and restricts its retraction limit, and a fixed piston 47 that supports the decompression piston 46.
7, and a return spring 48 which urges the pistons 46 in the direction of contact with the pistons 46.

47 is slidably fitted into a second cylinder hole 52 formed adjacent to the first cylinder hole 33 in the lid body 22b.

In the second cylinder hole 52 , the pressure reducing piston 46 defines a control hydraulic chamber 18 between the inner end wall of the second cylinder hole 52 and an output hydraulic chamber 55 between the fixed piston 47 and the inner end wall of the second cylinder hole 52 .
The fixed piston 47 also defines an input hydraulic pressure chamber 54 on its outer periphery.

The input hydraulic pressure chamber 54 communicates with the hydraulic chamber 36 of the hydraulic pump 16 via an oil passage 56, and the output hydraulic chamber 55 communicates with the hydraulic conduit 15 so as to constantly communicate with the manual port 14a of the front wheel brakes 3f, 3f. is connected to the downstream pipe 15b of
The control hydraulic chamber 18 is connected to the hydraulic pump 16 via an oil passage 57.
It communicates with the outlet chamber 57 of.

The fixed piston 47 is equipped with a valve chamber 58 that constantly communicates with the input hydraulic pressure chamber 54 and a valve hole 59 that communicates the valve chamber 58 with the output hydraulic pressure chamber 55. A valve body 60 that can be opened and closed and a valve spring 61 that biases the valve body 60 toward the closing side are housed. A valve opening rod 62 for opening the valve body 60 is provided protruding from one end surface of the pressure reducing piston 46, and this valve opening rod 62 opens the valve body 60 when the pressure reducing cylinder 46 is located at the retraction limit. Keep the valve open.

The outer opening of the second cylinder hole 52 is closed with an end plate 63 fixed to the lid body 22b, and the fixed piston 47 is operated by the elastic force of the return spring 48 or the output hydraulic chamber 54.5.
The hydraulic pressure introduced into the end plate 5 keeps the end plate 63 in contact with the end plate 63 at all times.

The hydraulic pump 16 and modulator 17 are arranged on the back side of the front fork 9 similarly to the brake caliper 14.

The exhaust pressure valve 20 is composed of a valve seat member 65 fitted into a stepped cylinder hole 64 of the lid body 22b, and a valve body 67 that slides onto the valve seat member 65 to open and close the valve hole 66 of the valve seat member 65. be done. The valve seat member 65 defines an inlet chamber 68 in the small diameter portion of the stepped cylinder hole 64 and an outlet chamber 69 in the large diameter portion thereof.
8.69 are communicated through the valve hole 66. Further, the inlet chamber 68 is communicated with the control hydraulic chamber 18 of the modulator 17 via an oil passage 20, and the outlet chamber 69 is communicated with the inlet chamber 31 of the hydraulic pump 16 via an oil passage 71. in the end,
The outlet chamber 69 is in communication with the oil tank 19.

The sensor 21 is connected to the front wheel 2 [input from the speed increasing gear device 4
5, a flywheel 72 rotated by the speed increasing device 45, a cam mechanism 73 that converts the overrun rotation of the flywheel 72 into axial displacement, and a cam mechanism 73 that converts the overrun rotation of the flywheel 72 into axial displacement, and It consists of an output rehar machine side 74 that can operate the pressure valve 20, a speed increasing gear device 45 is arranged on the outer side of the back wall of the housing 22a, and a cam mechanism 73
, the flywheel 72 and the output lever mechanism 74 are connected to the housing 2.
2a.

The speed-up gear device 45 includes a ring gear 76 that is spline-fitted to the inner peripheral surface of an annular support portion 75 protruding from the outer surface of the rear wall of the housing 22a, and a ring gear 76 that is rotatably supported by the hub 8. It is configured in a planetary gear type by a plurality of planetary gears 78 meshing with the drive shaft 42 and a sun gear 79 formed at one end of the drive shaft 42 and meshing with the planetary gears 78.

A sealing member 89 is interposed between the back wall of the housing 22a and the drive shaft 42 passing through it, and a sealing member 81 is also interposed between the hub 8 of the annular support portion 75 of the housing 22a. be done.

Even if the drive shaft 42 is overloaded for some reason, the front wheels 2
In order not to disturb the rotation of f, the speed increasing gear device 4
At least one of the gears 5, for example, the planetary gear 78, is made of synthetic resin and has a fuse function that ruptures when a torque exceeding a specified value is applied.

By the way, the speedometer 51 is connected to the speed increasing gear device 4.
5, so if the synthetic resin gear 78 were to break, the speedometer 51 would not operate despite the rotation of the front wheels 2f. From this, the above-mentioned failure can be known.

The cam mechanism 73 is connected to the drive shaft 42 as shown in FIG.
a driving cam plate 82 fixed to the drive cam plate 82; a driven cam plate 83 disposed opposite to the driving cam plate 82 so as to be relatively rotatable;
Cam recesses 82a and 83a on opposing surfaces of both cam plates 82 and 83
The thrust ball 84 is engaged with the thrust ball 84. The cam recess 82a of the temporary drive cam 82 is inclined so that the bottom surface becomes shallower in the direction of rotation 85 of the drive shaft 42, and the cam recess 83a of the driven cam plate 83 has a bottom surface that becomes deeper in the direction of rotation 85. It's slanted like that.

Therefore, in the normal case where the driving cam plate 8 takes a position on the driving side with respect to the driven cam temporary 83, the thrust ball 84 is engaged with the deepest part of both the cam recesses 82a, 82a, and the driving cam plate 8 simply transmits the rotational torque received from the drive shaft 42 to the driven cam plate 83 and does not cause relative rotation between the two cam plates 82 and 83. When you run,
Relative rotation occurs in both cam plates 82, 83, and the thrust ball 84 rolls up the inclined bottom surfaces of both cam recesses 82a, 83a, causing both cam plates 82, 834. m, 2. This causes the driven cam plate 82 to undergo axial displacement in the direction away from the drive cam plate 82.

The flywheel 72 has its post 72a connected to the drive shaft 4.
The driven cam plate 83 is rotatably and slidably supported on the boss 72a via a bushing 86, and the driven cam plate 83 is rotatably supported on the boss 72a, and is attached to one side of the flywheel 72 via a temporary friction clutch 87. is engaged with. A pressing plate 89 is attached to the other side of the flywheel 72 via a thrust bearing 88.

The output lever mechanism 74 swings in the axial direction of the axle 10 by a support shaft 90 protruding from the inner surface of the lid body 22b at an intermediate position between the axle 10 and the exhaust pressure valve 20, and a neck 90a at the tip of the support shaft 90. A lever 91 is freely supported, and a certain amount of play 92 is provided between the neck 90a and the lever 91 in the swinging direction of the lever 91. The lever 91 includes a long first arm 91a that extends from the support shaft 90 bypassing the drive shaft 42, and a short second arm 91a that extends from the support shaft 90 toward the exhaust pressure valve 20. An abutting portion 93 that abuts the outer surface of the pressing plate 89 is formed in a raised chevron shape at an intermediate portion of the pressing plate 89 .

A spring 94 is compressed between the tip of the first arm 91 and the lid body 22b, and the tip of the second bowl 91b is connected to the valve body 6 of the exhaust pressure valve 20.
7 Abuts on the outer end.

The elastic force of the spring 94 acts on the lever 91, and the first arm 91
The contact portion 93 of a is pressed against the pressing plate 89, and the valve body 67 of the exhaust pressure valve 20 is normally pressed to keep the valve closed.

The pressing force that the pressing plate 89 receives from the spring 94 is applied to the flywheel 72, the friction clutch plate 87, and the driven cam plate 8.
3, and both cams +f
Adds approach force to f182.83.

The friction engagement force is set so that when a rotational torque of a certain value or more is applied between the driven cam plate 83 and the flywheel 72, the friction clutch plate 87 slips.

A confirmation device 95 is connected to the output lever mechanism 74 to confirm its normal operation. This confirmation device 95
For example, a switch holder 96 is fixed to the lid 22b and protrudes into the coil portion of the spring 94, and a reed switch 97 is held by the switch holder 96 within the coil portion of the spring 94.
The first arm 91a is configured with a permanent magnet 98 attached to the first arm 91a in correspondence with the reed switch 97.
When the reed switch 97 swings a predetermined angle toward the lid 22b, the permanent magnet 98 is displaced to the closed position of the reed switch 97, and the display circuit 99
It is designed to operate.

In the above configuration, when the vehicle runs, the front wheels 2 rotate.
The drive shaft 42 is driven at an increased speed from r via the speed increasing gear device 45, and then the flywheel 72 is driven via the cam mechanism 73 and the friction clutch plate 87, so the flywheel 72 is driven at a higher speed than the front wheel 2f. Rotate with. Therefore, the flywheel 72 can have a large rotational inertia, and thereby the weight of the flywheel 72 can be reduced.

At the same time, the camshaft 26 and speedometer 5
1 is also driven by the drive shaft 42.

Now, if the front master cylinder 5f is operated to brake the front wheel 2f, the output oil pressure will be transferred to the upstream pipe 1 of the hydraulic conduit 15.
5a, hydraulic chamber 36 of hydraulic pump 16, modulator 17
Input hydraulic chamber 54, valve chamber 58, valve hole 59, output hydraulic chamber 5
5 and the downstream pipe 15b of the hydraulic conduit 15 to the front wheel brakes 3r and 3f, and actuate these to brake the front wheel 2f.
braking force can be added to the

On the other hand, in the hydraulic pump 16, since the output hydraulic pressure of the front master cylinder 5f is introduced into the hydraulic chamber 36, the hydraulic pressure acts on the operating piston 29 and the eccentric cam 26
A reciprocating motion is given to the pump piston 28 by the lifting action of a on the bushing rod 27. During the suction stroke in which the pump piston 28 moves toward the bushing rod 27, the suction valve 38 opens and the oil in the oil tank 19 is sucked into the pump chamber 35 from the m-pipe 37 via the population chamber 1, and the pump piston 28 is activated. In the discharge stroke to move toward the piston 29 side, the one-way sole part I'39 opens the valve, and the oil in the pump chamber 35 flows into the outlet chamber 32 and then through the oil passage 57 to the control hydraulic chamber of the modulator 17. 18. Then, when the pressure in the outlet chamber 32 and the control hydraulic chamber 18 rises to a predetermined value, the pump piston 28 is held in the abutting position with the stopper 34 by the pressure in the outlet chamber 32.

By the way, the control hydraulic chamber 18 of the modulator 17 is initially disconnected from the oil tank 19 by closing the exhaust pressure valve 20, so that the hydraulic pressure supplied from the hydraulic pump 16 to the chamber 18 is directly applied to the pressure reducing piston 46. The valve opening rod 62 maintains the valve body 60 in an open state, allowing the output hydraulic pressure of the front master cylinder 5r to pass through.

Therefore, at the beginning of braking, the front wheel brake 3f is applied.

The braking force applied to cylinder 3f is proportional to the output oil pressure of front master cylinder 5f.

When angular deceleration occurs in the front wheels 2f due to this braking, the flywheel 72 detects this and tries to overrun the drive shaft 42 due to its inertia force.

The rotational moment of the flywheel 72 at this time causes relative rotation of both cam plates 82 and 83, and the thrust generated by the displacement of the thrust ball 84 gives an axial displacement to the flywheel 72, causing the press plate 89 to move the lever. Trying to push -91.

Now, if we consider the behavior of the Leno\-91 when it is pressed by the pressing plate 89, initially there is play 92 between the support shaft 90 and the lever 91, so the lever 91 is moved by the spring 94, It is supported at three points: the pressing plate 89 and the valve body 67 of the exhaust valve 20, and when pressed by the pressing plate 89, it swings about the valve body 67 as a fulcrum. When such rocking progresses to a predetermined angle, the play 92 between the support shaft 90 and the lever 91 disappears,
Since the fulcrum on the second arm 91b side moves from the valve body 67 to the spindle 90 near the contact portion 93, the lever 91 now swings about the spindle 90 as a fulcrum.

In this way, the lever ratio when the lever 91 is swung by the pressing plate 89 changes in two stages, so even if the repulsive force of the spring 94 is constant, the lever 91 is initially moved by the relatively small force of the pressing plate 89. It oscillates due to the pressing force, and after the fulcrum of the oscillation moves, it does not oscillate unless the pressing force increases to a predetermined value. Therefore, during braking, when the angular deceleration occurring at the front wheel 2f is relatively small, the lever 91 is moved to the pressing plate 89.
Since the permanent magnet 98 is swung by the pressing force and brought close to the closed position of the reed switch 37, the display circuit 99 is activated and the operator can be made aware that the sensor 21 is operating normally. can.

Now, when the front wheel 2f is about to lock up due to excessive braking force or a decrease in the friction coefficient of the road surface, the front wheel 2f
Due to the sudden increase in the angular deceleration of f, the pressing force of the pressing plate 89 exceeds a predetermined value, and the lever 91 swings about the support shaft 90 to further compress the spring 94.
The arm 91b swings away from the valve body 67, and as a result, the exhaust pressure valve 20 becomes open.

When the exhaust pressure valve 20 opens, the oil pressure in the control oil chamber 18 is transferred to the oil passage 70. Entrance chamber 68. Valve hole 66, outlet chamber 69, oil passage 71.
Oil tank 1 via inlet chamber 31 of hydraulic pump 16 and conduit 37
9, the pressure reducing piston 46 moves toward the control hydraulic chamber 18 against the force of the return spring 48 due to the hydraulic pressure of the output hydraulic chamber 55, thereby retracting the valve opening rod 62 and opening the valve body 60. is closed to cut off communication between the person and the output oil chambers 54 and 55, and increase the volume of the output oil pressure chamber 55. As a result, the braking oil pressure acting on the front wheel brakes 3f, 3f decreases, the braking force of the front wheel 2'' decreases, and the locking phenomenon of the front wheel 2f is avoided.Then, as the rotation of the front wheel 2f accelerates, the pressing plate 89 Since the pressing force on the lever 91 is released, the lever 91 swings back to its original position due to the repulsive force of the spring 94, and closes the exhaust pressure valve 20.The exhaust pressure valve 20 is closed. Then, the pressure oil discharged from the hydraulic pump 16 is immediately confined in the control hydraulic chamber 18, and the pressure reducing piston 46
is retreated to the output hydraulic chamber 55 side to increase the pressure in the chamber 55 and restore the braking force. By repeating such operations at high speed, the front wheels 2r are efficiently braked.

In FIG. 2, a bypass 100 is provided that connects the input hydraulic chamber 54 and the output hydraulic chamber 55 of the modulator 17,
This bypass 100 functionally bypasses the modulator 17 and interconnects the upper and downstream pipes 15a, 15b of the hydraulic conduit 15. This bypass 100 includes an input hydraulic chamber 54
An orifice 101 and a check valve 102 are installed in series from the side, and the check valve 102 opens when the oil pressure of the input oil pressure chamber 54, that is, the output oil pressure of the front master cylinder 5f exceeds a specified high pressure value. The opening pressure of the check valve 1 is
It is determined by the set load of the valve spring 103 that urges the valve 02 in the valve closing direction.

During braking, if the exhaust pressure valve 20 is left open due to some kind of failure, the pressure reduction state in the control hydraulic chamber 18 of the modulator 17 continues, the pressure reduction piston 46 moves the valve opening rod 62 backward, and the valve body 60 However, at this time, if the output oil pressure of the front master cylinder 5r is increased to a specified high pressure value or higher, the check valve 102 opens and the upper part of the hydraulic conduit 15,
Since the downstream pipes 15a and 15b are communicated via the bypass 100, the output hydraulic pressure of the front master cylinder 5r can be transmitted to the front wheel brake 3f, and a desired braking force can be applied thereto.

At this time, since the transmission of the output hydraulic pressure of the front master cylinder 5f to the front wheel brake 3f is controlled slowly by the orifice 101 provided in the bypass 100, sudden operation of the front wheel brake 3f can be prevented.

C1 Effects of the Invention As described above, according to the present invention, a bypass that bypasses the modulator is connected to the brake oil path, and a check valve that opens when the output oil pressure of the master cylinder exceeds a specified high pressure value is installed in the bypass. Even if the pressure in the control hydraulic chamber of the modulator continues to be reduced due to a failure, as long as the output hydraulic pressure of the master cylinder is increased above the specified high pressure value, the master cylinder will be activated regardless of the modulator's operation. The output hydraulic pressure can be transmitted to the wheel brakes via a bypass to impart the desired braking force thereto.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic plan view of a motorcycle equipped with a braking device with an anti-lock control device, and FIG. 2 is a longitudinal cross-sectional side view of the main part of the braking device with an anti-lock control device. Figures 3 and 4 are III-II of Figure 2.
I line and TV-IV line sectional view, Figure 5 is V- of Figure 4
It is a V-line enlarged sectional view. 2f... Front wheel as a wheel, 3f... Front wheel brake as a wheel brake, 5f... Front master cylinder as a master cylinder, 7... Anti-lock control device, 15... As a braking oil path hydraulic conduit, 16...
Hydraulic pump, 17... Modulator, 18... Control hydraulic chamber, 19... Oil tank, 20... Exhaust pressure valve, 21...
・Sensor, 100... Bypass, 101... Orifice, 101... Check valve

Claims (1)

[Claims] a hydraulic pump driven by the wheels during braking; a modulator having a control hydraulic chamber supplied with the discharge pressure of the hydraulic pump and interposed in the brake oil passage between the master cylinder and the wheel brake; the control hydraulic chamber; and a normally closed exhaust pressure valve installed in a communication path between the oil tank and the oil tank; and a sensor that opens the exhaust pressure valve upon detecting that the wheels are about to be locked; In a vehicle anti-lock control device configured to control a brake oil passage in order to reduce the braking force of a wheel brake when the pressure in a control hydraulic chamber is reduced by opening a valve, a bypass that bypasses the modulator is provided in the brake oil passage. An anti-lock control device for a vehicle, characterized in that the bypass is provided with a check valve that opens when the output oil pressure of the master cylinder exceeds a specified high pressure value.