JPS6364857A - Brake device for vehicle - Google Patents

Abstract

PURPOSE:To obtain the optimum brake force in every wheel, by providing a variable regulator, which compares a generated oil pressure in a master cylinder with the generated oil pressure in an oil hydraulic pressure source introducing a high pressure to be inducted in a brake cylinder, and a modulator, having a movable piston, in the downstream part of said regulator. CONSTITUTION:A pressure of brake fluid in accordance with the depressing amount of a brake pedal 101 is generated in a master cylinder 103 and supplied to the first main pipe 151. A pressure of oil generated in an oil hydraulic motor 117 is accumulated in an accumulator 113. A variable pressure regulator 210, which introduces the pressure of oil from the master cylinder 103 to be inducted by a pilot pipe 156 switching a valve to be selected if the pressure of oil increases to a fixed value or more, feeds the pressure of oil in the accumulator 113 to an input chamber 412 of a modulator 410 in the downstream increasing a pressure of fluid in an output chamber 413, and the pressure of fluid in the master cylinder 103 is magnified and supplied to a wheel cylinder of a wheel. In this way, the optimum brake force can be obtained in every wheel.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a braking device for a vehicle, and is effective when used as a braking device for an automobile.

[Conventional technology]

Conventionally, vehicle braking systems have generally used hydraulic pressure, and are comprised of a master cylinder that converts the driver's brake operation force into hydraulic pressure, and a foil cylinder placed on each wheel that converts hydraulic pressure into braking force. has been done. In this case, in order to reduce the brake operation force of the driver, a booster (boosting device) that utilizes negative pressure of the engine is usually attached together with the master cylinder. However, in this case, when the driver operates the brake operating means, the boosting effect of the booster is applied to all the wheel cylinders arranged on each wheel. In other words, a uniform boosting effect is applied to all wheels. Therefore,
When the load on each wheel differs greatly, such as when a vehicle turns, it would be ideal to distribute the braking force to each wheel, but with conventional systems, it is difficult to apply the optimal braking force to each wheel. This caused the wheels to become unstable.

[Problem that the invention seeks to solve]

The present invention is intended to solve the problem that, as described above, a uniform braking force is applied to the foil cylinders provided on each wheel, and the optimum braking force cannot be applied to each wheel.

[Means for solving problems]

It has (a) a brake operating means, (b) a master cylinder that generates brake hydraulic pressure by operating the brake operating means, (c) a hydraulic pressure source that generates a substantially constant oil pressure, and (d) a movable piston. A modulator having an input chamber for receiving pressure at one end of the movable piston and an output chamber for outputting pressure at the other end, and (e) introduction of the constant hydraulic pressure source into the input chamber of the modulator. a variable pressure regulator that controls the amount of hydraulic pressure and also controls the amount of hydraulic pressure led out from the input chamber to the outside; and (b) a wheel cylinder that is arranged for each wheel and receives pressure to generate braking force for the wheel; g) a cut valve disposed in a passage connecting the output chamber of the modulator and the pressure release and communicating only when the output chamber is at maximum capacity; (h) brake hydraulic pressure generated by the master cylinder; The pressure from the hydraulic source is referenced and compared, and when the pressure from the hydraulic source is higher than the brake hydraulic pressure, the output chamber of the modulator and the wheel cylinder are communicated, and the pressure from the hydraulic source is smaller than the brake hydraulic pressure. Sometimes, the braking device for a vehicle is provided with a switching valve that communicates the master cylinder and the wheel cylinder.

〔Effect of the invention〕

By using the vehicle braking device of the present invention, the pressure supplied to each wheel cylinder can be controlled to be optimal by the variable pressure regulator, modulator, and cut valve arranged for each wheel. Therefore, the optimum braking force can be applied to each wheel, the posture of the vehicle can be stably supported, and the optimum braking force can be exerted.

In addition, when the output chamber of the modulator is at its minimum capacity, it communicates with the pressure release section through the cut valve, so the pressure oil in the output chamber expands when the brake is not applied, generating unnecessary pressure. Even if the pressure is released, it is released to the pressure release section through the cut valve. Moreover, even if the pressure oil in the output chamber decreases, pressure oil is replenished from the pressure release part via the cut valve.

〔Example〕

An embodiment of the present invention will be described based on the hydraulic circuit diagram shown in FIG.

A brake pedal 101, which is a brake operating means, is connected to a master cylinder 103 without the intervention of a booster. When the brake pedal 10i1@ is depressed, the master cylinder 103 generates brake hydraulic pressure according to the pedal force. The master cylinder 103 has two independent oil chambers, each of which has a first main pipe 151 and a second main pipe 153.
are connected.

The first main pipe 151 branches into a first technical pipe 155 and a second branch pipe 157, and these branch pipes 155 and 157 each have a switching valve 61.
0, the switching valve 620 is connected to the second capotro 12,622. Further, from the first main pipe 151, a pilot pipe 156 connected to the variable pressure regulators 210 and 220 is connected.
and a pyrosoto tube 166 is branched. Furthermore, the first
A third branch pipe 158 branches off from the main pipe 151 and connects to the input boat 511 of the supply valve 510 . Note that each branch pipe and each foil cylinder have completely the same configuration, so only the first main pipe 151 and the foil cylinder 105 will be described.

The electric motor 115 drives the hydraulic pump 117. A hydraulic motor 117 driven by the electric motor 115 sucks oil stored in a reservoir 180 from an inlet pipe 122 and discharges it to an outlet pipe 120. A check valve 123 is arranged in this introduction pipe 122,
Further, a check valve 121 is arranged in the outlet pipe 120. The hydraulic pressure discharged from the hydraulic pump 117 to the discharge pipe passes through this discharge pipe 120 to an accumulator (constant pressure az
It is stored in ta. This accumulator 113 is connected to a pressure pipe 170, and the pressure stored in the accumulator 113 is passed through the pressure pipe 170 to the variable pressure regulator 210.
guided by.

Note that the outlet pipe 120 and the inlet pipe 122 of the hydraulic motor 117 are connected by a relief pipe 127, and when the pressure from the hydraulic motor 117 exceeds a predetermined value, the relief pipe is connected to the outlet pipe. 120 to introduction pipe 1
A check valve 127 that connects only the direction toward 22 is provided.

Further, a pressure switch 119 is arranged on the pressure pipe 170 to detect the pressure stored in the accumulator 113.

The variable pressure regulator 210 has a first port 211 and a second port 21
2 and a third boat 213. The first port 211 is connected to the pressure pipe 170, and the second port 212 is connected to the reservoir 180 by a return pipe 172. Further, the third boat 213 is connected to the input chamber 412 of the modulator 140 via the input pipe 173.

The variable pressure regulator 210 connects the second port 212 and the third port 21
3 and a second position where the first port 211 and the third boat 213 are connected.

This variable pressure regulator 210 is a so-called spool type valve,
Switching is performed by detecting the reference pressure from a pilot pipe 156 branched from the first main pipe 151 and a second pilot pipe 190 branched from the input pipe 173.

Further, this variable pressure regulator 210 is also switched by electromagnetic force, and the first port 211 is switched depending on this electromagnetic force.
and the amount of communication between the third boat 213 or the second port 21
It is possible to control the amount of communication between the second and third boats 213 to an arbitrary value.

The modulator 410 has a cylindrical cylinder 450 in which a movable piston 411 is slidably inserted. This movable piston 411
A manpower chamber 412 and an output chamber 413 are defined by the cylinder 450 and the cylinder 450 . The input tube 17 is in the input chamber 412.
3 are connected. In addition, the output chamber 413 is connected to the output pipe 174.
The switching valve 610 is connected to the first capotro 11 by the switching valve 610. Note that there is a pressure spring 4 in the output chamber 413.
14 is arranged, and the movable piston 411 is connected to the input chamber 41.
It is biased towards 2.

The switching valve 610 is a three-point/two-position valve having a first person capo 611, a second person capo 12, and an output port 13. In the second position shown in the figure, the first person capo 1
In the first position, the second person capotro 12 and the output porto 13 are in communication, and the first man-powered boat is in the closed state. .

Switching between the first position and the second position is achieved by the hydraulic pressure in the accumulator 113, which is guided by a pilot pipe 191 branching from the pressure pipe 170, and by the master cylinder pressure, which is guided by a pilot pipe 192 branching from the first technical pipe 155. This is done by comparing.

That is, if the accumulator pressure is greater than the master cylinder pressure, it will be in the second position, and the output chamber 413 of the modulator 410 will be in the second position.
and the foil cylinder 105 are communicated with each other. Conversely, if the accumulator pressure is lower than the master cylinder pressure, the master cylinder 103 and the foil cylinder 105 are communicated.

The cut valve 310 is connected to the movable piston 411 of the modulator 410.
It operates in conjunction with the movement of the movable piston 4.
11 is at the stroke end on the side where the volume of the input chamber 412 is reduced as shown in FIG. When the first boat 311 and the second boat 312 are moved toward the output chamber 413, the first boat 311 and the second boat 312 are closed. This closed state is maintained until the movable piston moves again to the stroke end shown in FIG. The second boat 312 connects the modulator 41 with the branch pipe 161.
It communicates with the output chamber 413 of No. 0.

The supply valve 510 has a set extremely low pressure value (
For example, when it is less than 1 kg/cd gauge), it is in the open state, and when it is more than that, it acts as a check valve.

The input boat 511 is connected to the first main pipe 151 by a branch pipe 158.
In addition, the output boat 512 communicates with the first boat 311 of the cut valve 310 through a pipe 159 and a branch pipe 160.

Further, a viroft pipe 193 branches off from the branch pipe 158, and the supply valve 510 detects the master cylinder pressure from this viroft pipe 193.

In addition, each foil cylinder 105, 107, 109° 111
Pressure sensors 801, 802, 803, and 804 that detect the pressure of each foil cylinder are arranged on the upstream side of the pipe, and pressure sensors 801, 802, 803, and 804 that detect the pressure of each foil cylinder are also arranged in the first main pipe 151 and the second main pipe 153 to detect the pressure for this pipe. Pressure sensors 805 and 806 are arranged.

FIG. 3 is a cross-sectional view of modulator 410 and cant valve 310. First, the configuration of the modulator will be explained. A cylindrical cylinder 450 is formed inside the housing 415, and a movable piston 411 having a seal member 416 fitted around its outer periphery is slidably disposed within the cylinder 450.

Then, the movable piston 411 causes the cylinder 45
0 is divided into an input chamber 412 formed at one end of the movable piston 411 and an output chamber 413 formed at the other end. In addition, the movable piston 411 has a rod 316.
One end of the rod 316 is connected, and the other end of the rod 316 advances inside the output chamber 413 and reaches the cut valve 310 side, and a ball 314 is fixed to its tip.

Next, the configuration of the cut valve 310 will be explained.

The cut valve 310 adjacent to the modulator 410 has its valve seat member 315 fixed within the housing 415 via an O-ring 317 . The valve seat member 315 has a substantially cup shape with a port 311 at the bottom, and a valve seat 313 for opening and closing the boat 311 is formed at the tip of a cylindrical wall formed around the port 311. . This valve seat 3
The boat 311 is opened and closed by the ball 314 coming into contact with and separating from the ball 13 .

A substantially cylindrical rod holder 31 is provided inside the valve seat member 315.
9 is fixed, and the aforementioned rod 316 is inserted into this rod holder 319.

A spring 318 is disposed between the other end of the rod 316 and the rod holder 319.
A ball 314 fixed to the tip of the valve 6 urges the valve seat 313 in the direction of seating. The other end of the rod 316 slides inside the rod holder 319, and a slit 316a is formed on the outer periphery of the other end.
A predetermined gap 316b is also formed between the rod holder 319 and the rod holder 319.

A spring 414 is also arranged between the movable piston 411 and the rod holder 316, and urges the movable piston 411 toward the input chamber 412.

Note that the biasing force of this spring 414 is greater than the biasing force of the spring 318 described above.

FIG. 4 is a sectional view showing the configuration of the switching valve 610. A cylindrical cylinder 603 is formed in the housing 601, and a valve seat member 602 and a valve seat member 602 are formed in the cylinder 603.
A piston 614 inserted through the valve seat member 602 is disposed.

The piston 614 includes a rod portion 614a located within the valve seat member 602 and a pressure receiving portion 61 that slides directly on the cylinder 603.
4b. The pressure inside the accumulator 113 is introduced into the end of the pressure receiving part 614b by a pilot pipe 191, and the pressure receiving part 614b and the rod part 614a are connected to each other.
Master cylinder pressure from the master cylinder 103 is introduced into the connection portion with the master cylinder 103 via the pilot pipe 192 and the first technical pipe 155.

The housing 601 and the valve seat member 602 include a first person capotro 11, a second person capotro 12, and an output porto 13.
is formed. A first valve seat 615 is formed by the valve seat member 602 in the passage connecting the first person capotro 11 and the output port 13, and on the other hand, a first valve seat 615 is formed between the second person capotro 12 and the output port 13. A second valve seat 616 is formed in the passage by the valve seat member 602 so as to face the first valve seat 615 .

A ball 617 connected to an intermediate position of the piston 614 is located between the first valve seat 615 and the second valve seat 616.
By contacting and separating 16, the first capotro 11
Communication/cutoff between the output port 13 and the output port 13 is performed, and communication/cutoff between the second person port 12 and the output port 13 is performed.

FIG. 5 is a sectional view showing the configuration of the supply valve 510. A cylindrical space is formed in the housing 504, and a disc-shaped first plate 503 and a second plate 505 are arranged at the ends of this cylindrical space.

Further, a cylindrical member 502 having a cylindrical shape is disposed on the circumferential surface of the cylindrical space.

A communication hole 511a that communicates with a port 511 formed in the housing 504 is formed on the side surface of the cylindrical member 502, and a communication hole 51a is formed at a position facing the communication hole 511a.
A communication hole 511b having the same size as 1a is formed. This communication hole 511b communicates with a check valve passage 506 formed in the housing 504.

One end of the check valve passage 506 communicates with the communication hole 511b, and the other end communicates with a port 512 formed in the housing 504. A check valve consisting of a ball 515 and a spring 516 that biases the ball 515 is arranged in the check valve passage 506.
Only flow towards 1b is allowed.

In an internal space 508 formed by the first and second brakes 503, 505 and the cylindrical member 502, a flange 518 having a cylindrical space inside is disposed so as to be movable in the axial direction. A metal bellows 519 is connected between the flange 518 and the first plate 503, and a vacuum chamber 501 is formed therein.

A communication path 50 connecting the port 512 and the inside of the internal space 508 is provided in the second plate 505 at a position facing the port 512.
7 is formed. This communication path 507 is the communication path 50
When the poppet valve 513 seats and leaves the valve seat 514 formed at the open end of the valve 7, communication is interrupted.

The poppet valve 513 consists of a valve body portion and a spool portion, and the spool portion is movably disposed within the flange portion 518 through the communication path 507. Poppet valve 513 and flange 51
A spring 517 is arranged between the
This spring 517 forces the poppet valve 513 against the bottom of the flange 518.

When the master cylinder pressure in the master cylinder 103 is below a predetermined value (for example, below 1 kg/- gauge pressure), the flange 518 is located upward in FIG. 5, and the poppet valve 51
3, the communication path 507 is open. Therefore port 511
is connected to the port 51 via the internal space 508 and the communication path 507.
2 is in communication.

When master cylinder pressure is generated within the master cylinder 103, this master cylinder pressure 103 is introduced into the internal space 508 via the bow 511 and the communication hole 511a.

The flange 518 receives this introduced master cylinder pressure and moves downward in FIG. 5 while compressing the metal bellows 519.

Along with this, the poppet valve 513 also moves downward in the figure and seats on the valve seat 514, thereby closing the communication hole 511a. This allows the ports 511 and 512 to communicate only through the check valve passage 506.

Next, the operation of this embodiment will be explained. First, when the brake pedal 101 is not depressed, that is, in a non-braking state, the variable pressure regulator 210 is in the first position shown in FIG. Also, the movable piston 41 of the modulator 410
1 is located at the end of the input chamber 412 side, and the cut valve 310 is also located at the end of the input chamber 412 side.
It is located at

Further, the supply valve 510 is in the first position shown in FIG. 1 because the master cylinder pressure, which is the biloft pressure, is zero. The switching valve 610 is operated by two biloft pressures, that is, the accumulator pressure and the master cylinder pressure.If the hydraulic power system is normal, the accumulator pressure is generally higher than the master cylinder pressure, so it is shown in FIG. in the second position shown.

Next, when the driver depresses the brake pedal, brake hydraulic pressure is generated in the master cylinder 103 in accordance with the depressing force of the brake pedal. The low-pressure brake oil pressure at the initial stage of depression is applied to the first main pipe, branch pipe 158, supply valve 510, pipe 159° 160, cut valve 310, pipe 1
61 into the output chamber 413 of the modulator 410. Furthermore, brake oil is supplied to piping 174, switching valve 610, and piping 17.
5 to the wheel cylinder and generates a scraping low pressure. When the brake pedal is further depressed, the supply valve 510 changes to the second position by the master cylinder pressure received from the pilot pipe 510, and the variable pressure regulator 210 changes to the second position by receiving the master cylinder pressure via the pilot pipe 156. Therefore, as soon as the master cylinder pressure above the lowest level is received, the variable pressure regulator switches to the second position, and the first boat 211 and the third port 213 communicate with each other.

As a result, the constant pressure stored in the accumulator 113 flows from the first port of the variable pressure regulator 210 to the third port 213 via the pressure pipe 170. Then, via the input tube 173, the input chamber 41 of the modulator 410
2 will be introduced.

When the modulator 410 receives pressure from the accumulator in the input chamber 412, a movable piston 411 therein moves against the biasing force of the pressure spring 414. Furthermore, at the same time as the movable piston 411 moves, the cut valve 31
Since 0 is the second position, the movable piston 411 moves in a direction to decrease the volume of the output chamber 413. the result,
The pressure within the output chamber 413 increases, and this increased pressure is guided to the foil cylinder 105 via the output pipe 174.

The wheel cylinder 105 that receives this pressure converts this hydraulic pressure into braking force for the wheels, and brakes the right front wheel.

Note that the variable pressure regulator 210 introduces the reference pressure from the viroft tube 156 and the reference pressure from the second pilot tube 190, respectively. That is, the pressure flowing through the first main pipe 151 and the pressure flowing through the input pipe 173 are detected and switched. At this time, the pressure receiving area of the variable pressure regulator 210 that receives the pressure from the pilot pipe 156 is larger than that of the second pressure regulator.
It is larger than the pressure receiving area from the pilot tube 190. Here, if the ratio of this pressure receiving area is α, when the pressure received from the second viroft pipe 190 becomes α times the pressure received from the pilot pipe 156, the variable pressure regulator 210 returns from the second position to the original position. Switching to the first position allows the input pipe 173 to communicate with the return pipe 172. In other words, a pressure α times the pressure flowing through the first main pipe 151 flows through the input pipe 173.

When the oil pressure flowing through the input pipe 173 becomes larger than α times the oil pressure flowing through the first main pipe 151, the variable pressure regulator 210 switches to the first position shown in FIG. It communicates with the return pipe 172 through the third port 213 and the second boat 212, and as a result, the pressure within the input chamber 412 is returned to the reservoir 180 via the input pipe 173 and the return pipe 172. Therefore, the pressure flowing through this man-powered pipe 173, that is, the pressure introduced into the input chamber 412, is always suppressed to α times the hydraulic pressure flowing through the first branch pipe 155.

Since the pressure receiving area on the input chamber 412 side and the pressure receiving area on the output chamber 413 side of the movable piston 411 are set equal, if a certain pressure is introduced into the input chamber 412, the pressure will also be applied to the output chamber 413. The same pressure will be generated. That is, a pressure that is a predetermined double of the pressure flowing through the first branch pipe 155 (pressure from the master cylinder) is transferred from the output pipe 413 to the output pipe 174 and the piping 175.
It will be introduced into the foil cylinder 105 via. That is, the variable pressure regulator 210 and the modulator 410 act to boost the pressure from the master cylinder 103. Further, at this time, the wheel cylinder pressure is generated only by the output pressure of the variable pressure regulator 410, and is effectively a full power brake.

When the cut valve 310 and the supply valve 510 are not braking,
This is to prevent residual pressure from remaining in the wheel cylinder 105 and the output chamber 413 or from becoming a negative pressure, and when the brake is not applied, the wheel cylinder 1
05 indicates piping 175, output pipe 174, output chamber 413, piping 161, 160, piping 159, 158, first main pipe 15
1. The master cylinder 103 is open to atmospheric pressure via a reservoir (pressure release section).

Therefore, even if the pressure oil in the output chamber 413 and the foil cylinder 105 expands under some conditions, the expansion pressure is transferred to the master cylinder 103 via the cut valve 310 and the supply valve 510.
is released into a reservoir 104 (pressure release part) connected to. Therefore, there is no problem that pressure is generated in the output chamber 413 and the wheel cylinder 105 and the wheels are braked even though the brakes are not being applied.

In addition, even if the pressure oil in the foil cylinder 105 or the output chamber 413 leaks due to some malfunction and the oil amount decreases, the pressure in the reservoir 104 will be reduced to the supply valve 510,
The output chamber 413 is replenished via the cut valve 310.

Further, the supply valve 510 is a second valve that acts as a cut valve by a low-pressure master cylinder supplied from the master cylinder 103.
Therefore, even though the master cylinder is sufficiently generated, the switching of the variable pressure regulator 210 is delayed, and the movable piston 411 does not move and the cut valve 31
0 remains in the open state, from the master cylinder 103 to the first main pipe 151, branch pipes 158, 159, piping 160,
Cut valve 310, piping 1611 output chamber 413, output pipe 1
74, the passage toward the foil cylinder 105 via the switching valve 610 and the piping 175 is instantly shut off by the supply valve 510 after the master cylinder pressure is generated.

Therefore, even in such a case, the master cylinder 10
3 is not introduced into the output chamber 413 of the modulator 413, no extra pressure is generated in the output chamber 413, and when the movable piston 411 is moved as far as possible to the input chamber 412 side. , the pressure inside the output chamber 413 can be reduced to an appropriate value.

Next, during normal braking as described above, the vehicle's attitude and weight distribution to each wheel may change due to changes in road surface conditions, changes in steering angle, increased amount of brake pedal depression, etc. . For example, if we take changes in the posture of the vehicle and the weight distribution to each wheel, more load will be applied to some wheels, and the load will be reduced to some wheels. Assuming that the road surface condition (friction coefficient, etc.) is constant, the braking force that a wheel can absorb is approximately proportional to the vertical load applied to that wheel, so when a change in attitude occurs, the braking force exerted by a wheel whose load decreases will decrease. This will reduce the available braking force. That is, if a braking force greater than the reduced absorbable braking force is applied to that wheel, it will try to stop rotating regardless of the speed of the vehicle body, resulting in a so-called locking phenomenon.

In order to prevent such a situation early, rotation sensors 811, 812 installed on each wheel, pressure sensors 8゜1, 802 installed on each wheel cylinder, and pressure sensors installed on the first main pipe 151. 803 detects a potential lock tendency of the wheels and supplies reduced pressure power to the variable pressure regulator 210 via an electronic control unit (ECU) 820. The variable pressure regulator 210 supplied with power for this pressure reduction moves from the second position to the first position as shown in FIG.
A force is applied in the direction of switching the position, and a pressure lower than the α times the pressure of the master cylinder described above is output. Note that in this case, the applied force will be controlled according to the amount of power supplied to the variable pressure regulator 210. That is, the amount of oil drawn out in the input chamber 412 is controlled by the amount of supplied current.

If the pressure inside the input chamber 412 decreases, the movable piston 41
1 receives the biasing force of the pressure spring 414, and the input chamber 4
Move to the 12th side. As a result, the volume inside the output chamber 413 increases, and the pressure inside the foil cylinder 105 decreases to the output pipe 174.
It will be led out to this output chamber 413 side via. Therefore, the pressure in this wheel cylinder 105 is reduced, the braking force of this wheel is reduced, and a braking force distribution commensurate with the vertical load is achieved.

In the above explanation, an example was explained in which the load on the right front wheel was reduced, but in this case, the pressure in the foil cylinder 105 of the wheel cylinders 107, 109° 111 arranged for the other three wheels is reduced. The pressure supplied to each wheel cylinder increases by the amount reduced, thereby maintaining the stability of the vehicle as a whole.

Further, a case where the driver depresses the brake pedal 101 excessively, that is, a case where the vehicle is in an emergency will be described.

When the driver depresses the brake pedal 101 excessively, pressure corresponding to the depressing force is generated from the master cylinder 103, the variable pressure regulator 210 is switched, and the pressure from the accumulator 113 is transferred to the input chamber 41 of the modulator 410.
2 will be introduced. Excessive pressure is then supplied to the foil cylinder 105 from this modulator 410. Then, the oil pressure of this wheel cylinder 105 increases excessively, causing each wheel to tend to lock.

In this case, vehicle sensors 811 disposed on the wheels detect this locking tendency and send a detection signal to an electronic control unit (ECU) 820. Upon receiving this detection signal, the ECU 320 controls the variable pressure regulator 21.
0, the variable pressure regulator switches from the first position to the second position shown. Therefore, the input room 41
The pressure inside the input chamber 412 is returned to the reservoir 180 via the input pipe 173 and the return pipe 172, and the pressure inside the input chamber 412 is reduced. The movable piston is the input chamber 41
2 side, the volume within the output chamber 413 increases, and as a result the pressure supplied within the foil cylinder 105 decreases. In addition, in the above-mentioned example, although only the wheel cylinder 105 was explained, exactly the same operation|movement is performed about each wheel.

Next, a description will be given of when the vehicle suddenly starts. If the driving force is suddenly transmitted to the driving wheels when the vehicle starts, the vehicle will not be accelerated, and only the wheels will spin, resulting in a phenomenon in which a stable start cannot be performed. In order to prevent wheels from spinning even when the wheels suddenly start, the following operations are performed.

That is, wheel speed sensors 811 to 8 provided on each wheel
14 detects this idling, it transmits a detection signal to the ECU 320. ECU 320 receiving this detection signal sends a switching signal to variable pressure regulator 210 to switch to the second position. Then, the variable pressure regulator is switched to the second position, and the first port 211 and the third port 213 communicate with each other. That is, the accumulator 113
The pressure stored in the pressure pipe 170 and the first boat 211
, the third boat 213, and the modulator 41 via the input tube 173.
0 input 412. Then, the variable piston 411 receives the pressure inside the input chamber 412 and moves into the output chamber 4.
Move to the 13th side. When the volume within the output chamber 413 decreases, the pressure within the output chamber 413 increases, and this increased pressure is guided to the foil cylinder 105 via the output pipe 174.

That is, the pressure inside the wheel cylinder 105 increases, and the braking force of this wheel increases, thereby suppressing the wheel from spinning.

Although this operation has been explained only for the wheel cylinder lO5, the same operation is performed for the wheel cylinder 107 disposed on the same drive wheel. Moreover, as mentioned above, the variable pressure regulator 210 supplies the switching position! Since it is variable by magnetic force, the pressure led from the accumulation rake 113 to the input chamber 412 of the modulator 410 is variably controlled.

Furthermore, the above-mentioned wheel slippage during a sudden start can be easily detected by comparing the detection outputs of the wheel speed sensors installed on the driving wheels and the wheel speed sensors installed on the driven wheels. .

In addition, in the operation at the time of sudden start mentioned above, the variable pressure regulator 2
10 switches to the second position, hydraulic pressure is output to the input pipe 173, and the movable piston of the modulator 410 moves, and in conjunction with this, the cut valve 310 switches to the second position,
Master cylinder 103 and output chamber 413 of modulator 410 are isolated. In other words, master cylinder 103 and foil cylinder 105 are disconnected.

Note that when the pressure of the hydraulic power source decreases due to an abnormality in the hydraulic power source, by first monitoring the state of the pressure switch 119, the above-mentioned wheel lock prevention control, wheel slipping prevention control, or braking force distribution is stopped and appropriate measures are taken. The pressure modulator 210 is operated only by pilot input pressure. When the hydraulic pressure source pressure further decreases and becomes lower than the master cylinder pressure, the switching valve 610 switches to the first position, and the master cylinder 1
Pressure oil from 03 is delivered to the foil cylinder 105 via the first main pipe 151, the first technical pipe 155, the switching valve 610, and the pipe 175.
is supplied to ensure wheel braking.

FIG. 2 is a hydraulic piping diagram showing a second embodiment of the present invention.
In this embodiment, the reservoir 10 is directly connected to the piping 160 communicating with the boat 311 of the cut valve 310 via the piping 163.
4 (pressure release section). In this configuration, the piping 163 is required, but the supply valve 5 as in the first embodiment
10 becomes unnecessary. The other configurations and operations are the same as those of the first embodiment described above.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic piping diagram showing a first embodiment of the present invention, Fig. 2 is a hydraulic piping diagram showing a second embodiment, Fig. 3 is a sectional view showing a modulator and a cut valve, and Fig. 4 is a switching diagram. Sectional view showing the valve, No. 5
The figure is a sectional view showing the supply valve. 103...Master cylinder, 105, 107, 109
．． 111...Foil cylinder, 113...Accumulator, 210,220,230,240...Variable pressure regulator, 310,320.330..., 340...Cut valve, 410,420,430.440... ...Modulator, 610,620,630.640...Switching valve.

Claims (1)

[Scope of Claims] (a) a brake operating means; (b) a master cylinder that generates brake hydraulic pressure by operating the brake operating means; (c) a hydraulic pressure source that generates a substantially constant oil pressure; ) a modulator having a movable piston, in which an input chamber for receiving pressure is formed at one end of the movable piston and an output chamber for outputting pressure at the other end; (f) A variable pressure regulator that controls the amount of hydraulic pressure introduced into the input chamber and the amount of hydraulic pressure led out from the input chamber to the outside; (g) a cut valve disposed in a passage connecting the output chamber of the modulator and the pressure release and communicating only when the output chamber is at its maximum capacity; (h) generated by the master cylinder. The brake oil pressure is compared with the pressure from the oil pressure source, and when the pressure from the oil pressure source is higher than the brake oil pressure, the output chamber of the modulator and the wheel cylinder are communicated, and the pressure from the oil pressure source is A braking device for a vehicle, comprising a switching valve that communicates the master cylinder and the wheel cylinder when the pressure is lower than the brake hydraulic pressure.