JPH0138689B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake device for a vehicle, etc., and particularly to one equipped with a brake control valve for starting on an uphill road.

Conventionally, this type of device has been equipped with at least two brake systems that supply pressurized fluid from the brake master cylinder to the brake wheel cylinders through mutually independent piping systems, and one system has a system that detects that the road is uphill. It is known to include a brake control valve which can prevent fluid movement from the brake wheel cylinder to the brake master cylinder and which can be opened and closed in response to actuation of the clutch device.

In order to easily start a vehicle on an uphill road, such a device maintains the pressure in the brake wheel cylinder in response to a clutch disengagement operation performed following a brake engagement operation when stopping on an uphill road. The vehicle is maintained in a stopped state even after the brake operation is completed, and when the vehicle is started, the pressure is released in response to the clutch connection operation. As a result, when starting on an uphill road, the vehicle can be safely operated by performing two operations: depressing the accelerator pedal and gradually releasing the clutch pedal without operating the handbrake at the same time. This makes it possible to start the vehicle immediately, and prevent accidents caused by the vehicle or the like moving backwards due to failure to start.

However, in such devices, the brake control valve for maintaining pressure in the wheel cylinders is only installed in one of the multiple systems, so the total braking force required to maintain the stopped state of the vehicle, etc. is limited. There is a problem in that the vehicle backs up with the clutch pedal depressed after the brake operation is completed and an accident occurs.

In other words, in recent vehicles, the brake piping system is separated into one that includes a brake wheel cylinder for the front wheel and one that includes that for the rear wheel, or a so-called front and rear piping system that includes a brake wheel cylinder for the front right wheel and a brake cylinder for the rear left wheel. In most cases, the so-called X piping system includes one that includes a brake cylinder for the front left wheel and one for the rear right wheel, and in such piping systems, only one piping system Even if the pressure is maintained, the pressure at the time of stopping by supplying pressure to two systems is maintained, so the braking force for stopping is halved, and the vehicle or the like ends up moving backward.

For this reason, the applicant first installed brake force control valves equipped with balls that move under their own weight in parallel, and made the two balls movable by a single camshaft linked to clutch operation. 55-21250)
proposed the above-mentioned problem in a two-system brake system.

According to this proposal, the lack of braking force can be solved, but since two balls are moved from the valve seat where the balls are seated on one camshaft against the pressure acting on the balls, this problem occurs. The camshaft requires a considerable amount of driving force, and as a result, the force required to press the clutch pedal becomes large, making the clutch heavy, making it difficult to operate the clutch quickly, and releasing the brake pressure at the time of starting off smoothly. I have a problem where I am unable to start.

The present invention was made in view of the above-mentioned problems, and aims to provide a brake device that allows starting on an uphill road with a light operation. A movable valve is provided with a valve device that can prevent fluid movement from the brake wheel cylinder of the other system toward the brake master cylinder, and is movable by receiving pressure on the brake wheel cylinder side of the brake control valve of at least one system. A body is provided, and the valve device is opened in response to movement of the movable body.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The brake device of the present invention will be explained in detail below based on illustrated examples.

FIG. 1 is an overall view of a brake device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line A--A in FIG.

In FIGS. 1 and 2, the brake device is indicated as 1 as a whole, and the device 1 includes a brake tandem master cylinder 2 having two independent hydraulic pressure generating chambers (not shown) formed inside. have.

This master cylinder 2 is attached to the vehicle body A and is actuated by a brake pedal 3 swingably attached to the vehicle body A, and one hydraulic pressure generating chamber is connected to piping 4, 5 and a brake control valve. 6
It is connected to the brake wheel cylinders (not shown) of the brake device 7 of the right front wheel and the brake device 8 of the left rear wheel through the hydraulic pressure generating chamber of the other side.
It communicates with brake wheel cylinders (not shown) of a brake device 12 for the left front wheel and a brake device 13 for the right rear wheel via an automatic valve 11 provided integrally with the pipes 9 and 10 and the brake control valve 6. .

Particularly, the brake control valve 6 will be explained with reference to FIG.
4 is provided with a stepped hole 15 whose diameter gradually increases in the forward direction of the vehicle, and a hole 16 extending perpendicularly to the stepped hole 15. (In Figures 1 and 2,
The forward direction of the vehicle, etc. is to the left when facing the figure. ) A camshaft 17 is rotatably inserted into the hole 16, and a camshaft 17 is inserted into the hole 16 of the stepped hole 15.
A cam 18 whose diameter is eccentrically reduced is provided at a portion opposite to the opening end of the piping system. A cam chamber 21, which forms part of the cam chamber 21, is partitioned. This cam chamber 21 is connected to the pipe 4 via a connection hole 22.

A recess 23 is provided at the lower end of the camshaft 17 to increase the volume between the camshaft 17 and the closed end of the hole 16, while the upper end of the camshaft 17 has a reduced diameter to increase the volume between the camshaft 17 and the closed end of the hole 16. A connecting portion 24 protrudes outward,
A rotating member 25 having a substantially triangular shape is attached to the connecting portion 24 using a nut 27 and a washer 28 along with a skirt member 26 for keeping out water.

Referring to FIG. 1, this rotating member 25 is connected to a wire 29 at one end (detailed shape and structure is not shown and is shown schematically), and swings the clutch actuating arm 30. Correspondingly, the camshaft 17 can be rotated together with the camshaft 17 by or against the tension of a release spring 31 stretched between it and the vehicle body A on the other end side.

Further, the camshaft 17 is prevented from coming out of the hole 16 by a sliding device 32 provided at the open end of the hole 16, and is guided to slide during rotation. The sliding device 32 includes a low-friction sliding member 33 made of synthetic resin and having a cylindrical shape with a flange that contacts the camshaft 17.
, a back upper 34 and a stopper 35. 36 is waterproof and dustproof boots.

On the other hand, a ball guide 38 having an automatically movable spherical valve element 37 fitted therein is fitted into the large diameter hole of the stepped hole 15, and a lid 39 is screwed onto the stepped hole 15. A washer 41 with an elastic piece 40 provided between the lid 39 and the ball guide 38 holds it in the illustrated position where it abuts against the stepped portion 42 .
An axial groove 43 is provided on the inner surface of this ball guide 38.
A valve seat assembly 44 on which the valve element 37 can be seated is fitted to the end of the stepped portion 42 .

This valve seat assembly 44 includes a seat member 45 made of rubber.
The seat member 45 is made up of a supporting member 46 that is connected to the seat member 45 by unevenness. By fitting the wall of the ball guide 38 into a groove 47 formed on the outer periphery of the seat member 45, the ball guide 38 can be attached to the ball guide 38. Installed in one piece. The seat member 45 has an annular protrusion (not shown) formed on the outer periphery for sealing the space between the seat member 45 and the inner surface of the intermediate diameter portion of the stepped hole 15.
An inner hole 48 is bored therein, and a plate portion 50 that can come into contact with the stepped portion 49 of the stepped hole 15 is formed.

A plunger 52 is movably inserted into the small diameter portion of the stepped hole 15 with a light spring 51 stretched between it and the support member 46 of the valve seat assembly 44. It is brought into contact with the cam 18 by the tension of 51. Further, the plunger 52 has a large number of axial grooves 53 formed on its outer periphery, and a valve seat assembly 44 on the left end side.
A small diameter portion 54 is formed that penetrates through the ball guide 38 and protrudes into the ball guide 38 to be able to come into contact with the valve element 37.

Automatic valve 11 provided integrally with brake control valve 6
Specifically, to explain with reference to FIG. 1, there is a stepped hole 55 formed in the main body 14 parallel to the stepped hole 15, and the stepped hole 55 gradually becomes larger in diameter toward the right. It has a small diameter hole 57 and a large diameter hole 58 formed with a stepped portion 56 interposed therebetween.

The stepped hole 55 has a large diameter portion 59 in the small diameter hole 57,
A differential piston 61 with a small diameter portion 60 fitted into the large diameter hole 58 is movably inserted into the end of the small diameter hole 57 and is connected to the pipe 5 through a connecting hole 62 and connected to the hole 63.
The first pressure chambers 64 each communicating with the stepped hole 15 are defined through the opening end of the large diameter hole 58.
Together with a plug 66 that is screwed onto the open end and forms a connection 65 for the pipe 10, it communicates with the pipe 10 and also connects to the pipe 9 through a connection 67 provided in communication with the large diameter hole 58. Communicating second pressure chamber 68
are divided.

On the outer periphery of the small diameter portion 60 of the differential piston 61, there are 2
A sealing member 70 sandwiched between two rings 69 is fitted to seal between the small diameter portion 60 and the large diameter hole 58, and at the end of the small diameter portion 60,
A valve member 71 made of rubber is attached by a spring receiver 72, and a light valve spring 73 disposed between the spring receiver 72 and the plug 66 causes the differential piston 6 to
1 is biased to the right.

A seat surface 74 is formed on the end surface of the plug 66 facing the valve member 71, and communication between the piping 10 and the second pressure chamber 68 can be cut off by the seat surface 74 and the valve member 71. A valve 75 is configured. Further, at the open end of the plug 66 with respect to the second pressure chamber 68, there is a throttle passage 76 that exhibits an effect as described later.
is provided.

In addition, in FIGS. 1 and 2, 77 is a clutch pedal, 78 is a clutch wire provided between the clutch pedal 77 and the clutch operating arm 30,
79 is an engine, 80 is a transmission device, and 81 is a clutch device including the arm 30. Note that these devices and the like are shown schematically to make the explanation easier to understand.

The clutch device 81 includes a flywheel 82 that rotates together with the engine 79, a pressure plate 83, a block 84 that moves on an axis in accordance with the swinging of the arm 30, and a diaphragm that is disposed between the plate 83 and the block 84. Spring 8
5, and a clutch disk 86 which is disposed between the wheel 82 and the plate 83 and can be frictionally engaged with both. Incidentally, since such a clutch device 81 is widely known, a detailed explanation thereof will be omitted.

In addition, in FIGS. 1 and 2, the member indicated by a is
A sealing member that is selected and used as appropriate depending on the installation location,
The member indicated by b is a back-up spring for sealing member a, the point indicated by d is the center of rocking or rotation of the pedal, etc., and the point indicated by e is the connection point between the pedal etc. and the wire. Each location is indicated.

The functions of the device 1 will be described below.

Assume that the driver of the vehicle is not operating the brake or clutch and is driving the vehicle at an appropriate speed.

Then, the clutch disk 86 frictionally engages with the fly hole 82 and the pressure plate 83 under the action of the maximum load of the diaphragm spring 85, resulting in a so-called clutch connected state. The plunger 52 is moved to the left by the cam 18 as the plunger 52 is urged to the illustrated position by the tension of the plunger 5.
The small diameter portion 54 of No. 2 is located at a position that protrudes into the ball guide 38 beyond the valve seat assembly 44, and when the vehicle or the like runs on an uphill road, the valve element 37 attempts to seat on the valve seat assembly 44. I'm in a state where I can't even do it. Also, since the brakes are not applied,
No pressure is generated inside each piping system, and the differential piston 61 is in both pressure chambers 64, 68.
Since the valve spring 73 is not receiving pressure from the valve 75, the valve spring 73 is in a position where the valve 75 is opened.

While driving on an uphill road in this condition, for example, when the driver approaches a railroad crossing and depresses the brake pedal 3 to apply the brakes, pressurized fluid is discharged from the master cylinder 2 to the pipes 4 and 9, and each Pressure is generated in the piping system and pressurized fluid is supplied to the wheel cylinders of each brake device, so the brakes begin to apply. At this time, for the brake devices 7 and 8, the piping 4, the cam chamber 21, the groove 53 of the plunger 52, the inner hole 48 of the valve seat assembly 44, the inside of the ball guide 38, the hole 63, the first pressure chamber 64, For the brake devices 12 and 13 via the pipe 5,
Pressure fluid is supplied independently from the master cylinder 2 via the piping 9, the second pressure chamber 68, and the piping 10.

When pressure is transmitted into each pressure chamber 64, 68, the differential piston 61 receives a larger pressure acting on the large pressure receiving area on the left end side than the acting force on the small pressure receiving area on the right end side. Although the differential piston 61 tries to move to the right, since the stepped portion of the differential piston 61 engages with the ring 69, there is no force exerted to the right to overcome the force applied to the pressure receiving area on the right side of the sealing member 70. Therefore, the differential piston 61 is located at the illustrated position where the ring 69 engages with the stepped portion 56 of the stepped hole 55 and the stepped portion of the differential piston 61. (It is assumed that the pressures generated in the two hydraulic pressure generating chambers of the master cylinder 2 are substantially equal.) Thereafter, when the vehicle etc. is sufficiently decelerated, the driver depresses the brake pedal 3 and releases the clutch. Depress pedal 77 deeply. Then, the clutch pedal 77 swings (or rotates) about point d.
Hereinafter, this will be simply referred to as "oscillation." ), the clutch actuating arm 30 is moved to point d via the clutch wire 78.
In the clutch device 81, the diaphragm spring 85 moves to the left as the block 84 moves to the left.
is used as a fulcrum, the pressure plate 83 is deformed away from the flywheel 82, and the frictional engagement of the clutch disk 86 with the pressure plate 83 and the flywheel 82 is completely released, resulting in a so-called clutch disengaged state. becomes. On the other hand, at the same time, due to the rocking of the clutch actuating arm 30, the rotating member 25 of the brake control valve 6 moves counterclockwise in FIG. Rotate against the force. The rotation of the rotation member 25 causes the camshaft 17 to
rotates, and as the cam 18 and plunger 52 slide and the cam 18 is displaced, the plunger 52 moves to the right due to the biasing force of the spring 51, and finally the valve element 37 is attached to the valve seat assembly 44. The small diameter portion 54 is moved sufficiently to the right to allow the user to sit.

In this state, when the vehicle etc. comes to a complete stop and the driver removes his foot from the brake pedal 3, the valve element 37
The piping 4 is separated by the contact area between the valve seat assembly 44 and the valve seat assembly 44.
The pressure on the piping 5 side is released, but the pressure on the piping 5 side is maintained as it is.

Furthermore, in the automatic valve 11, although the pressure in the second pressure chamber 68 decreases as the pressure on the piping 9 side decreases, the pressure in the first pressure chamber 64 is maintained as it is. When the pressure in the pressure chamber 68 decreases to a certain extent, the rightward movement force that the differential piston 61 receives from the pressure in the first pressure chamber 64 on the left end side is transferred to the second pressure chamber 68 on the right end side.
The leftward moving force is caused by the direct reception of internal pressure, and the leftward moving force is caused by the hydraulic pressure acting on the right side of the sealing member 70 acting on the differential piston 61 via the ring 69. (Since the biasing force of the valve spring 73 is small, it will be ignored in this explanation, and the sliding resistance will also be ignored.), and the differential piston 61 moves to the right. and closes the valve 75.

At this time, the pressure inside the pipe 10 decreases slightly by the time the valve 75 closes, but since the pipe 10 and the second pressure chamber 68 are in communication via the throttle passage 76, the pressure inside the pipe 10 is restricted. As the effect is designed to prevent an extreme pressure drop, in the end,
It will also be automatically held within the piping 10.

Therefore, since the pressure is maintained in the wheel cylinder of each brake device 7, 8, 12, 13, the same pressure is maintained in the brake devices 7, 8, in particular.
Since the brake devices 12 and 13 each maintain a slightly reduced pressure, the total braking force is slightly smaller than the total braking force when the vehicle is stopped on an uphill road, but it is sufficient to maintain a stop on an uphill road. You can get a lot of braking force.

With this operation, the vehicle or the like is kept in a stopped state with the clutch pedal 77 depressed, the clutch being disconnected, and the brakes being fully applied.

Next, a case where the driver starts the vehicle will be described.

Now, as mentioned above, in order to start the vehicle from a stopped state by depressing only the clutch pedal 77, the driver first depresses the accelerator pedal (not shown) and increases the rotational speed of the engine 79 slightly. While doing so, the clutch pedal 77 is gradually returned to the inoperative position (return position). Then, the clutch actuating arm 30 swings in the opposite direction to when the clutch is disengaged, and the clutch disc 86 receives a portion of the maximum load of the diaphragm spring 85, causing the flywheel 82 and pressure plate 83 to move.
This results in a so-called half-clutch state in which the clutch is frictionally engaged with the clutch. In addition, in the brake control valve 6, the rotating member 25
is rotated clockwise by the biasing force of the release spring 31, and the cam 18 is accordingly displaced to move the plunger 52, and the small diameter portion 54 of the plunger 52 is rotated clockwise.
By bringing the valve element 37 into contact with the valve element 37 and separating the valve element 37 from the valve seat assembly 44, the pressure within the pipe 5 is released to the master cylinder 2 side. As the pressure in the pipe 5 decreases, the differential piston 61 moves the pipe 1 so that its horizontal movement forces are balanced.
Reduce the pressure within 0.

With this, the wheels (driving wheels) are driven by the engine 7.
9 through the clutch device 81, the pressure in each wheel cylinder decreases, and the braking force applied to the wheels gradually decreases. Can be started on the road.

After starting, if the clutch pedal 77 is fully returned,
The clutch is now fully engaged and the pressure in each wheel cylinder has also been released, resulting in normal driving.

According to the above-described embodiment, in the system including the pipes 4 and 5, a device is provided which allows the valve element 37 to be seated and removed from the valve seat assembly 44 in conjunction with the clutch operation, and the system including the pipes 9 and 10 is provided. In the system, it is detected that the pressure is confined within the pipe 5,
In other words, when the brake control valve 6 is activated, the pressure is also contained within the piping 10, so that stopping on an uphill road is prevented by containing the brake pressure in two systems. It is possible to secure sufficient braking force for
At the time of starting, the operating force required to displace the valve element 37 is sufficient, so the operating force can be kept small. Furthermore, by being able to reduce the operating force, the brake can be released quickly when starting, and the braking force can be reduced to an appropriate braking force in a half-clutched state, making it possible to start easily. You will be able to do it smoothly.

Further, in the automatic valve 11, in order to open and close the valve 75, the differential piston 61 is moved by the difference in the biasing force or moving force in the left and right direction acting on the differential piston 61. In other words, since the differential piston 61 is moved by comparing the pressure sealed on the piping 5 side and the internal pressure of the master cylinder 2 on the piping 9 side,
The operating state of the brake control valve 6 and the operating state of the master cylinder 2 can be reliably determined to open and close the valve 75, and the automatic valve 11 and the brake control valve 6 work together to maintain a stop on an uphill road. Not only can this be done reliably, but also the brake can be released when starting.
The reliability of the entire device is excellent.

As described above, various effects are achieved according to the embodiments described above, but the present invention can be implemented without being limited to the embodiments described above.

FIG. 3 shows another embodiment of the invention. In addition, in the one shown in Fig. 3, the first and second
Portions or components that have substantially the same function, structure, or shape as those shown in the figures are given the same symbols as those in FIGS. 1 and 2, and their explanation will be omitted, and particularly differences will be described.

In FIG. 3, two liquid connections 90 and 91 are formed by directly communicating with the stepped hole 15, and
The automatic valve 11' is directly attached to the open end of the stepped hole 15 with bolts or the like (not shown).

The automatic valve 11' has a main body 95 formed by connecting upper and lower liquid connecting portions 92 and 93 to an inner hole 94, and the inner hole 94 gradually increases in size toward the left with a stepped portion 96 interposed therebetween. The left end of the inner hole 94 is closed by a lid 97, and the right end communicates with the stepped hole 15 through a small hole 98. Further, a substantially axially shaped differential piston 99 is movably inserted into the inner hole 94 .
The piston 99 is biased to the right by a light spring 102 disposed between the left end recess 100 of the lid 97 and the recess 101 of the lid 97.

An inner hole 94 is provided on the outer periphery of the left side of the differential piston 66.
A lip-seal type sealing member 103 seals between the piston 99 and the back-up part 10 at the stepped portion 96
The sealing member 1 is arranged adjacently through the sealing member 1.
A small hole 106 that can be displaced from side to side in the inner lip 105 of 03 is formed in the cylindrical portion that forms the recess 100 of the differential piston 99. Also, the sealing member 10
A through hole 107 is provided in the inner hole 94 on the right side of the cylinder 3, and a part of the inner hole 94 communicates with a hydraulic pressure generating chamber (not shown) of the master cylinder through the through hole 107. Ru.

Note that the connecting portions 90 and 92 are connected to the brake wheel cylinder of the front wheel brake device, and the connecting portions 91 and 9
3 are respectively connected to those of the rear wheels, and are connected by an X piping system similar to the piping system shown in FIGS. 1 and 2.

The operation of this embodiment is as follows.

When the brake is applied, the pressure of one system is transmitted from the small hole 98 into the inner hole 94, and the differential piston 9
9 receives the force of movement to the left, and the through hole 107
pressure from the other system is transmitted into the inner hole 94,
The pressure from this other system further passes through the small hole 106 and deforms the inner lip 105 to form the inner hole 94.
As a result, the differential piston 99 receives a rightward movement force. When braking, these differential pistons 9
9 is balanced, and the differential piston 99 is in a position where the small hole 106 is located on the right side of the inner lip 105.

Then, the clutch is operated to seal the pressure in the stepped hole 15 and release the brake.

Then, the pressure between the sealing member 103 and the sealing member a in the inner hole 94 decreases, and the pressure in the inner hole 94 on the left side of the sealing member 103 also decreases.
06 gradually decreases, and the force that tries to move the differential piston 99 to the left increases until the small hole 106 of the differential piston 99 is located on the left side of the inner lip 105. do. Although this causes a slight pressure drop in the other system,
Pressure is contained.

When starting, the differential piston 99 moves to the right due to the pressure drop in the stepped hole 15 and moves into the small hole 10.
6 is located on the right side of the inner lip 105, and the pressure of the other system is released through the small hole 106.

According to the above-described embodiment, in addition to the same effects as the previous embodiment, the following effects are also obtained.

That is, in this embodiment, the differential piston 99
Even when the lip moves to the left, the medial lip 1
05 can be modified to supply pressurized fluid from the master cylinder side to the wheel cylinder side, so when installing it on an actual vehicle, the system on the stepped hole 15 side should be vented first. Even if the inner hole 94 side is closed, air can be easily vented from the system on the inner hole 94 side.

More specifically, the inner lip 105 functions like a check valve that allows fluid to move from the master cylinder side to the wheel cylinder side, but prohibits the reverse flow, and prevents backflow of brake fluid during air bleeding operations. (liquid movement toward the master cylinder side), air can be removed quickly and easily.

Further, by operating the clutch following the brake operation, preparations can be made to seal pressure in each system, but even if even higher pressure is generated in the brake piping system after this preparation is completed, the pressure difference between the valve elements 37 By moving and deforming the inner lip 105,
This high pressure can also be transmitted to the wheel cylinder side without impairing braking performance.

Furthermore, even when only normal braking operation is performed and no clutch operation is performed, the left and right pressure receiving areas of the differential piston 99 are made equal, so that brake pressure is not unnecessarily confined to the other system. Brake performance will not be impaired.

As described above, the second embodiment also provides various effects.

As is clear from the above, according to the present invention, one system is provided with a brake control valve that can maintain pressure in response to clutch operation, and the other system is provided with a brake control valve on the brake wheel cylinder side of at least one system of brake control valves. By providing a valve device that receives pressure and closes the valve by moving a movable body, it is possible to obtain a brake device that requires less operating force and allows smooth starting on an uphill road. be.

Although various things have been described above, it goes without saying that the present invention can be practiced without being limited to the illustrated examples.

That is, the configuration of the brake control valve itself can be changed from that shown in the figure, for example, as shown in Japanese Utility Model Application Publication No. 55-16930, a reciprocating camshaft is used instead of a rotating camshaft. Or, Utsukai Showa 55-
As shown in Japanese Patent No. 33822, a clutch that utilizes the hydraulic pressure of a hydraulic clutch may also be used. Also,
In the example shown in FIG. 3, the sealing area of the piston 99 by the sealing member 103 is made equal to that by the sealing member a, but the former is made slightly smaller than the latter to prevent pressure drop when maintaining the stop. Of course, this is a good thing. On the other hand, the former is made slightly larger than the latter (within a range that does not adversely affect stopping on an uphill road, in other words, within a range that does not cause insufficient braking force), so that during normal brake operation, the other system is The brake may be released preferentially. Furthermore, in the illustrated example, pressure drop on the wheel cylinder side is prevented by the throttling effect of the throttling passage 76 or the small hole 106, but piping resistance can be reduced even without providing a small passage with a throttling effect. If there is sufficient pressure remaining on the wheel cylinder side to ensure a stop, there is no need to provide a small passage as described above, and if piping resistance etc. is extremely small, or if the movement of the differential piston In cases such as when the time required for the process is long, restrictive small passages may be provided to the extent necessary.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a sectional view taken along line A--A in FIG. 1, and FIG. 3 is a sectional view showing another embodiment. DESCRIPTION OF SYMBOLS 1... Brake device, 2... Tandem master cylinder, 6... Brake control valve, 9, 10... Piping, 11... Automatic valve, 59... Differential piston, 7
5... Valve.

Claims (1)

[Claims] 1.Equipped with at least two brake systems that supply pressurized fluid from the brake master cylinder to the brake wheel cylinder through mutually independent piping systems, one system is equipped with a brake master cylinder that supplies pressurized fluid from the brake master cylinder to the brake master cylinder when it detects that the road is uphill. A brake device including a brake control valve that can prevent fluid movement toward the cylinder and that can be opened and closed in response to actuation of a clutch device,
The other system is provided with a valve device that can prevent fluid movement from the brake wheel cylinder of the other system toward the brake master cylinder, and receives the brake wheel cylinder side pressure of the brake control valve of at least one system. A brake device that is provided with a movable body and closes the valve device according to the movement of the movable body.