JPS62187638A - Antiskid type hydraulic brake device - Google Patents

Abstract

PURPOSE:To attempt the employment of a pump drive device which is small in size and light in weight by providing a buffer to a pump line equipped with an accumulator feeding pressure fluid to a hydraulic pressure control valve provided to a brake fluid line. CONSTITUTION:Both a proportioning valve 18 and a hydraulic pressure control valve 20 are provided to a hydraulic line 16 connecting a master cylinder 12 with a rear wheel cylinder 22 for controlling hydraulic pressure in a hydraulic pressure chamber 30 in a hydraulic pressure control section 24 of the hydraulic pressure control device 20 by means of both a pressure increase/decrease change- over solenoid valve 40 and a bake control solenoid valve 42. And a pump 76 is also provided for feeding its discharge fluid to an accumulator 70 through a check valve 72 so as to transmit the fluid pressure of the accumulator 70 to the hydraulic pressure control device 20 through a regulator 46. And a buffer 91 is provided to a place closer to the pump 76 (76) side than the check valve 72 of a pump line 74, and a discharge valve 110 which is opened upon receiving controlled pressure from the regulator 46, is provided to a circulating fluid path 112, by which the buffer is connected with a reservoir 50.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an automatic Ichikawa anti-skid type hydraulic brake system, and in particular to a pump start-up system that includes an accumulator as a hydraulic pressure source and a pump that supplies fluid thereto. It is related to load reduction.

BACKGROUND OF THE INVENTION Some conventional hydraulic brake systems for automobiles are known as anti-slip, F-type brake systems. The hydraulic pressure of the wheel cylinder during braking can be controlled so that the slip ratio of the wheel relative to the road surface does not deviate from an appropriate range. This type of anti-skid type hydraulic brake device uses a pump to pump up fluid and store it in an accumulator at high pressure.The fluid pressure in the accumulator is then controlled by a regulator to a control fluid pressure that increases or decreases as the master cylinder's fluid pressure increases or decreases. There is a type that reduces the pressure and then supplies it to a hydraulic pressure control valve that controls the hydraulic pressure of the wheel cylinder.

In this way, when the brake is not applied, fluid is stored in the accumulator with high hydraulic pressure using a small pump.
When the brake is applied, a sufficient amount of fluid can be supplied to the hydraulic pressure control valve, and the fluid supplied to the hydraulic pressure control valve is reduced by the regulator to a hydraulic pressure close to the hydraulic pressure in the brake cylinder, and the hydraulic pressure is controlled. Since it is supplied to the valve, the hydraulic pressure of the wheel cylinder can be easily controlled.

Problems to be Solved by the Invention In the above-mentioned hydraulic pressure supply device, when the hydraulic pressure in the accumulator drops to the lower limit hydraulic pressure, the pump is activated to replenish the liquid. However, since it is necessary that the hydraulic pressure is sufficient to control the hydraulic pressure of the wheel cylinders, it is usually set to a high value of about 140 kg/cIA, for example. therefore,
It is necessary for the pump to discharge liquid against this high liquid pressure from the beginning of startup, and at startup, the pump drive device has a load based on this liquid pressure and an inertial load of the pump and pump drive device itself. Therefore, there is a problem in that the pump drive device inevitably becomes large and heavy.

Means for Solving the Problems In order to solve the above problems, the present invention provides (a) a master cylinder that generates hydraulic pressure in response to operation of a brake operating member, and (b) a brake that suppresses rotation of wheels. (C) provided in a fluid passage connecting the wheel cylinder and the master cylinder;
an anti-skid control device comprising a hydraulic pressure control valve that controls the hydraulic pressure of the wheel cylinder and a controller that controls the hydraulic pressure control valve to maintain the slip ratio of the wheel with respect to the road surface within an appropriate range; (e) a pump that pumps water up and supplies the fluid to the accumulator through a pump passage equipped with a check valve;
pump control means for controlling stop; and (f)n? ? In the anti-skid type hydraulic brake device, the pump passage includes a regulator that reduces the hydraulic pressure of the accumulator to a control hydraulic pressure that increases or decreases in accordance with an increase or decrease of the hydraulic pressure of the master cylinder, and supplies the reduced hydraulic pressure to the hydraulic pressure control valve. A buffer for accommodating a working fluid at a pressure lower than that of the accumulator is provided in a part of the pump side of the check valve, and the buffer is connected to the reservoir through a reflux path, and the reflux path is always blocked. The drain valve is provided with a drain valve that is switched to a state in which the reflux path is communicated by receiving the controlled hydraulic pressure of the regulator.

Operation In such an anti-skid type hydraulic brake system, the pump is always stopped and the buffer is empty. Then, when it becomes necessary to replenish the accumulator with liquid and the pump is activated, the discharged liquid is first absorbed into the buffer. Therefore, the pump does not need to discharge liquid against high hydraulic pressure from the beginning of startup, and the pump driving device is mainly subjected to the inertial load of the pump and the pump driving device.

Only when the buffer is saturated will the pump discharge fluid be supplied to the accumulator, and a load based on the hydraulic pressure will be applied to the pump drive device, but by this time the pump and pump drive device has reached a steady operating speed and the inertial load has disappeared, so the pump driving device is not subjected to the inertial load and the load based on high hydraulic pressure.

The fluid stored in the buffer is drained into the reservoir when the brakes are applied. When the brakes are applied, control fluid pressure is supplied from the regulator to the fluid pressure control valve, but this control fluid pressure is also simultaneously supplied to the drainage valve installed in the reflux path, and the drainage valve connects the reflux path. Because it can be switched to the state,
The liquid stored in the buffer flows back to the reservoir via the reflux path.

Effect As described above, according to the present invention, the inertial load of the pump and pump drive device itself and the load based on high hydraulic pressure are not applied to the pump drive device, so the pump drive device can be made small and lightweight. The effect that can be achieved is obtained. Furthermore, the fluid absorbed in the buffer to reduce the starting load is returned to the reservoir by switching the drain valve using the control fluid pressure supplied from the regulator when the brakes are applied, so electrical control means are not required. do not. For example, the same purpose could be achieved by using a solenoid valve, but the solenoid valve itself is expensive and requires a fail-safe system to deal with the failure of its control circuit or control circuit. In addition to being expensive, the solenoid valve is a doll and requires wiring, so there are many restrictions on where it can be installed.However, according to the present invention, these inconveniences can be overcome. .

Also, the reason why it is necessary to replenish fluid in the accumulator is because the fluid in the accumulator is consumed when the brake is activated, so the brake must be applied before the pump is restarted once it has been stopped. The buffer is empty when activated, ensuring that startup load is reduced every time.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a system diagram of an anti-skid type hydraulic brake system, in which numeral 10 represents a brake pedal and numeral 12 represents a master cylinder. The master cylinder 12 is of a tandem type with two mutually independent pressurizing chambers, and the hydraulic pressure generated in each pressurizing chamber is transferred through liquid passages 14 and 16 to the front wheel cylinder of the front wheel brake and the rear wheel cylinder, respectively. The signal is transmitted to the wheel brake system and the wheel cylinder, but only the rear system is representatively shown in the figure.

The liquid passage 16 connects the master cylinder 12 and the puller wheel cylinder 22 via a provisioning valve 18 and a liquid pressure control device 20. The push-down valve 18 reduces the hydraulic pressure in the master cylinder 12 at a constant rate, but since it is well known, a detailed explanation will be omitted. The hydraulic pressure control device 20 includes a hydraulic pressure control section 24
and a bypass section 25. The hydraulic pressure control section 24 includes a directional switching valve 26 and a hydraulic pressure control piston 28, and controls the hydraulic pressure of the rear wheel cylinder 22 according to the hydraulic pressure in the hydraulic pressure chamber 30. 32 and a bypass piston 34, which allows the master cylinder 12 and rear wheel cylinder 22 to communicate with each other via a bypass passage 38 when hydraulic pressure ceases to act on the hydraulic pressure chamber 36.

The hydraulic pressure in the hydraulic chamber 30 of the hydraulic pressure control section 24 is controlled by a pressure increase/decrease switching solenoid valve 40 and a slow/slow control solenoid valve 42. The pressure increase/decrease switching solenoid valve 40 excites the solenoid 43,
With degaussing, the hydraulic pressure chamber 30 is switched between a state in which it is communicated with the regulator 46 via the warm color control solenoid valve 42 and the liquid passage 44, and a state in which it is communicated with the reservoir 50 via the liquid passage 48. It increases or decreases the hydraulic pressure. On the other hand, by changing the duty ratio of the pulsed excitation current supplied to the solenoid 52, the solenoid valve 42 for speed control can change the ratio of the time it is in the open state and the time it is in the closed state. This controls the speed and speed of decompression. That is, both electromagnetic valves 40 and 42 are indirectly connected to the rear wheel cylinder 22 via the hydraulic pressure control device 20.
This constitutes a hydraulic pressure control valve that controls the hydraulic pressure of the rear wheels and prevents the rear wheels from locking up. solenoid 43
And the excitation and demagnetization of 52 are done with a microphone (not shown)! This is performed by a controller mainly based on a computer, and this controller, solenoid valves 40, 42, and hydraulic pressure control device 2
0 constitutes an anti-skid control device, but since this controller is well known, a detailed explanation will be omitted.

The regulator 46 is equipped with a control piston 60 and a directional switching valve 62, and the hydraulic pressure of the master cylinder 12 is guided to a hydraulic pressure chamber 64 on one side of the control piston 60 through a hydraulic passage 66. ing. Based on the increase/decrease in master cylinder pressure, the control piston 60 switches the directional control valve 62 between communicating the hydraulic chamber 68 with the high pressure accumulator 70, communicating with the reservoir 50, and communicating with neither. , thereby reducing the hydraulic pressure of the high-pressure accumulator 70 to a hydraulic pressure higher than the master cylinder pressure by a predetermined value, and the above-mentioned slow/sudden control solenoid valve 42 and hydraulic pressure control device 2
0 and 0.

One end of a pump passage 74 is connected to the high pressure accumulator 70 via a check valve 72.

The other end of the pump passage 74 is connected to a pump 76, and a portion of the pump passage 74 is formed by a high pressure rubber hose 78. Pump 76, pump motor 80
The pump motor 8
0 is started and stopped by the controller based on the output signal of the hydraulic pressure switch 82 provided in the high pressure accumulator 70, whereby the high pressure accumulator 70
The hydraulic pressure inside is maintained within a predetermined range. The controller and the pressure switch 82 constitute pump control means. 84 is a relief valve.

A buffer 90 is connected to a portion of the pump passage 74 closer to the pump 76 than the check valve 72 . This buffer 90
A stepped buffer piston 96 having a large diameter portion 92 and a small diameter portion 94 is fitted into a housing 98 having a stepped hole, and is urged toward the small diameter portion 94 by a spring 100.

Three cavities are formed between the buffer piston 96 and the housing 98, and among them, the annular cavity formed at the stepped portion between the large diameter portion 92 and the small diameter portion 94 is
2 and a liquid passage 104 to the pump passage 74, which serves as a buffer chamber 106. Also,
The cavity formed on the front side of the small diameter part 94 is communicated with the atmosphere through a port 108, and the cavity formed on the rear side of the large diameter part 92 is communicated with the atmosphere through a drain valve 110 and a reflux path 112. A hydraulic chamber 114 is connected to the reservoir 50.

The drain valve 110 is a directional switching valve that can switch between communicating the hydraulic chamber 114 with the buffer chamber 106, communicating with the reservoir 50, and not communicating with any of the above. Formed valve seat 11
6 and a valve seat 120 formed on the valve piston 118 are provided with a ball 122 as a common valve element. Hydraulic chamber 1
14 is connected to the buffer chamber 106 by a liquid passage 124 formed through the buffer piston 96,
A fluid passage 126 formed in the valve piston 118 communicates with the reservoir 50, and when the ball 122 seats on the valve seat 116, the fluid pressure chamber 11
4 and the buffer chamber 106 is cut off, and the ball 12
2 is seated on the valve seat 120, communication between the hydraulic pressure chamber 114 and the reservoir 50 is reduced. A hydraulic chamber 128 formed on the rear side of the valve piston 118 is located at the rear side of the valve piston 118.
130 and a fluid passageway 132, it is connected to the fluid pressure chamber 68 of the regulator 46. The cross-sectional area S of the small diameter portion 94 of the bypass piston 96 is the same as that of the valve piston 118.
is made larger than the cross-sectional area S2 of. The reason for this will be explained in detail later.

In the hydraulic brake device configured as described above, when the brake is not operating, the master cylinder 12
, the hydraulic pressure in the accumulator 70 is reduced to a low pressure of about 5 kIr/crl by the regulator 46, and the hydraulic pressure chambers 30, 3 of the hydraulic pressure control device 120 are
6. This hydraulic pressure keeps both the hydraulic control piston 28 and the bypass piston 34 in the forward position, and the bypass passage 38 is blocked and the master cylinder 1
2 and the wheel cylinder 22 are communicated with each other via a liquid passage 16.

Therefore, when the brake pedal 10 is depressed and brake fluid is discharged from the master cylinder 12, this fluid is supplied to the rear wheel cylinder 22 through the fluid passage 16 and the brake is operated. If the rotation restraint force on the wheels is excessive in relation to the road surface friction coefficient v, the slip rate of the rear wheels will increase, so a controller (not shown) will control the solenoid valve 4.
0.42 is activated and the hydraulic pressure in the rear wheel cylinder 22 is controlled. This hydraulic pressure control is performed by increasing or decreasing the hydraulic pressure in the wheel cylinder 22. When increasing the pressure, the high pressure liquid stored in the accumulator 70 is reduced by the regulator 46, and then the solenoid valve 42
．． It is supplied to the hydraulic pressure chamber 30 of the hydraulic pressure control device 20 via 40, and is discharged to the reservoir 50 via the electromagnetic valve 40 when the pressure is reduced. That is, the high pressure fluid stored in the accumulator 70 is consumed every time the anti-skid device is activated.

As a result of this consumption of high pressure fluid, accumulator 7
When the hydraulic pressure in 0 drops to the lower limit hydraulic pressure, it is detected by the hydraulic pressure switch 82, and the controllers 1 to ?- (not shown) are detected.
The pump motor 80 is started by the driver. As the pump motor 80 starts, the pump 7G starts discharging liquid, but this discharge? a first flows into the buffer chamber 106 of the buffer 90. Since the biasing force of the spring 100 of the buffer 90 is set small, the buffer piston 96 is retracted with low hydraulic pressure. Therefore, when the pump 76 is started, the accumulator 70
There is no need to discharge the liquid against the high liquid pressure inside, and the pump motor 80 is hardly subjected to any load based on the liquid pressure, and only the inertial loads of the pump 76 and the pump motor 80 themselves are applied.

When the buffer piston 96 retreats to the retracted end and contacts the housing 98 as shown in FIG. Become. Therefore, a load is applied to the pump motor 80 due to the high hydraulic pressure, but at this point, the pump 76 and the pump motor 80 have reached a steady operating speed, and the inertial load has disappeared. Inertia in pump motor 80! This prevents the load and the load due to high liquid positive from being applied at the same time.

When the hydraulic pressure in the accumulator 70 reaches the upper limit hydraulic pressure, this is detected by the hydraulic pressure switch 82, and the controller stops the pump motor 80 based on the detection signal. However, the liquid absorbed in the buffer chamber 106 of the buffer 90 cannot be returned to the reservoir 50 because the liquid passage 124 is blocked by the drain valve 110 and the pump 76 is also provided with a discharge valve. Buffer room 1
He remains trapped in 06.

Next, when the brake is operated and the hydraulic pressure in the hydraulic pressure chamber 68 of the regulator 46 increases, this hydraulic pressure is guided to the hydraulic pressure chamber 128, the valve piston 118 is advanced, and the third valve piston 118 is moved forward.
It contacts the ball 122 as shown in the figure. As the valve piston 118 moves forward, the capacity of the hydraulic chamber 114 decreases, but since the liquid passage 126 is not blocked, the liquid in the hydraulic chamber 114 flows out to the reservoir 50 through the liquid passage 126. , thereby allowing advancement of the valve piston 118.

After the valve piston 118 contacts the ball 122, if the valve piston 118 moves further forward as shown in FIG. As a result, the buffer piston 96 is moved forward toward the buffer chamber 106 by the urging force of the spring 100, and the liquid in the buffer chamber 106 flows out to the hydraulic pressure chamber 114. At this point, the ball 122 is seated on the valve seat 120 and the fluid passage 126 is closed, so the fluid pressure chamber 1
The liquid No. 14 cannot be returned to the reservoir 50, and all the liquid flowing out from the buffer chamber 106 is accommodated in the hydraulic pressure chamber 114. Therefore, if the cross-sectional area S□ of the small diameter portion 94 of the buffer piston 96 is
8, the buffer chamber 106
The liquid in the buffer chamber 106 cannot flow to the hydraulic pressure chamber 114, but in this embodiment, the size of this cross-sectional box is reversed as described above, so the liquid in the buffer chamber 106 can flow to the hydraulic pressure chamber 114 without any problem. can flow to chamber 114. That is, in FIG. 3, the buffer piston 96 and the valve piston 11 are connected with the ball 122 slightly away from the valve seat 116.
8 and move them to the left in that state.
06, I? The I reduction amount and the volume increase amount of the hydraulic chamber 114 must be equal to each other. If the amount of decrease in the volume of the buffer chamber 106 is larger than the amount of increase in the volume of the hydraulic pressure chamber 114, the amount of liquid flowing into the hydraulic pressure chamber 114 will be excessive, and conversely, the amount of decrease in the volume of the buffer chamber 10G will increase the volume of the hydraulic pressure chamber 114. This is because if it is smaller than the large amount, there will be a shortage of liquid flowing into the hydraulic pressure chamber 114S.

a. Here, since the buffer piston 96 and the valve piston 118 are not fixed integrally, the valve piston 118 can move back with respect to the buffer piston 96, thereby causing the hydraulic pressure chamber to The volume of 114 increases. Therefore, from only the point of view of the change in 8 points, even if Si<32 and the capacity reduction plate of the buffer chamber 106 is larger than the amount of increase in the 8 points of the hydraulic chamber 114, η
However, when the valve piston 118 moves back relative to the buffer piston 96, the ball 122 moves toward the valve r!
1126 and the liquid passage 124 is blocked, so that the liquid in the buffer chamber 106 cannot flow to the hydraulic pressure chamber 114 after all. On the other hand, when S□>S2 as in this embodiment, the valve piston 118 approaches the nopanopha piston 96, resulting in a decrease in the volume of the buffer chamber 106 and an increase in the volume of the hydraulic pressure chamber 114. In this case, the fifth
As shown in the figure, the distance of the ball 122 from the valve seat 116 only increases, and the buffer chamber 106 and the hydraulic pressure chamber 114 are kept in communication, so that the liquid in the Ha2 and Fa chambers 106 can flow without any problem. It can flow to the hydraulic chamber 114.

Thus, once the brake is applied, the buffer chamber 106. Since the hydraulic pressure in the pump passage 74 decreases, the time during which high hydraulic pressure acts on the high-pressure rubber hose 78 becomes shorter, extending its life. When the brake pedal 10 is released, the control fluid from the regulator 46 When the pressure no longer acts on the valve piston 118, the valve piston 118 is retracted by the biasing force of the spring 100. With this retraction, the volume of the hydraulic pressure chamber 114 increases, and its hydraulic pressure decreases, so that the liquid passage 126 and the hydraulic pressure chamber 114. Due to the hydraulic pressure difference, the ball 12
2 is lifted from the valve seat 120, liquid flows from the reservoir 50 into the hydraulic pressure chamber 114, and the valve piston 118 is allowed to retreat to its original position (retreat end) shown in FIG. The liquid valve 110 returns to its original state.

As is clear from the above description, when the pump 76 is started while the brake is not in operation, the discharged fluid overcomes the biasing force of the spring 100 and flows out.

It is sufficient to move the pump piston 96 backward, and the pump motor 8
However, if the pump 76 is started while the brake is in operation, the pump 76 will be affected by the hydraulic pressure in the hydraulic pressure chamber 68 of the leg, the spring, and the Buffer chamber 1 based on a biasing force of 100
It is necessary to retract the buffer piston 96 against the liquid pressure generated at 06. During brake operation, the knob piston 118 is in the state shown in FIG. 4, so the fluid discharged from the pump 76 first flows into the buffer chamber 106. The liquid flows into the liquid pressure chamber 114 through the liquid passage 124 and moves the valve piston 11B backward against the control liquid pressure of the regulator 4G guided to the liquid pressure chamber 128. Eventually, the ball 122 will come into contact with the valve seat 116 and the liquid passage 124 will be blocked, but after that, the discharged liquid will move the buffer screw 1-96 backward, and as a result, the liquid pressure in the liquid pressure chamber 114 will decrease. increases, causing the half piston 118 to retreat, and the ball 122
Since the valve seat 120 is separated from the valve seat 120, the liquid in the hydraulic pressure chamber 11 can flow out through the liquid passage 126 to the reservoir 50-1, and the hydraulic pressure in the hydraulic chamber 114 is 1
28 and is maintained at a level equal to the control hydraulic pressure of the 1-' generator 46. And this 41
Buffer chamber 1 of buffer piston 96 in F, 3
Since the pressure receiving area on the 06 side is smaller than the pressure receiving area of the hydraulic pressure chamber 114, the hydraulic pressure in the buffer chamber 106 becomes higher than the hydraulic pressure in the hydraulic pressure chamber 11ll, and the pump 76 resists the 1.1 pressure. It is therefore necessary to retract the buffer screw 1-96. In this sense, the buffer piston 96
The pressure receiving area of the buffer chamber 1065 and the hydraulic pressure chamber 114
It is desirable that the difference between the pressure receiving area and the small diameter portion 94Q)liIrTF surface sr and the cross section fi1S2 of the valve piston 118 be as small as possible.

In this way, when the pump 76 is activated during brake operation, the pump 76 needs to discharge fluid against the fluid pressure generated in the buffer chamber 106 based on the controlled fluid pressure of the regulator 46. Since the hydraulic pressure generated in this buffer chamber 106 is normally lower than the lower limit hydraulic pressure of the accumulator 70, even in this case, the pump motor 8
Therefore, the starting load reduction effect of 0 can be obtained. However, during brake operation, the hydraulic pressure in the accumulator 70 is at the lower limit i &
Even if the pressure is reached and the hydraulic pressure switch 82 detects it, the controller will not operate the pump motor 8 until the brake is released.
0 may not be activated, and in this way, it is possible to always maximize the effect of reducing the activation load by the buffer 90.

Further, in the above embodiment, the buffer 90 and the drain valve 1
10 share a housing 98, and the buffer piston 96 of the buffer 90 forms part of the drain & valve 110, but as shown in FIG. It is also possible to configure them independently of each other. The functions of each component of the buffer 140 and the drain valve 142 are almost the same as those in the above embodiment, so parts that perform the same functions are given the same reference numerals to indicate correspondence, and detailed explanations will be given. The explanation will be omitted. In addition, in the above-mentioned embodiment, components that were one component divided into 2Hj are given the same reference numerals with a and b added.

In this embodiment, when the pump is started, the discharged liquid is absorbed into the buffer chamber 10G, thereby reducing the starting load. Chamber 114b, liquid passage 12
6 and flows out into the reservoir 50. On the other hand, the liquid absorbed in the buffer chamber 106 is absorbed by the valve piston 118 as shown in FIG. 6 when the brake is applied.
By moving the ball 122 away from the valve seat 116, the liquid passage 124a, the hydraulic pressure chamber 114b, and the liquid passage 12
4b and into the hydraulic pressure chamber 114a, and the device returns to its original state.

Another embodiment of the invention is shown in FIGS. 7 and 8. In this embodiment, a buffer 150 is configured such that a chamber 156 formed on the opposite side of the buffer chamber 154 with a buffer piston 152 in between communicates with the atmosphere, and a drain valve 1
58 is a spool type. That is, the drain valve 158 includes a spool 160, which is normally kept at the retracted end by a spring 162, and which connects the buffer chamber 154 to the liquid passage 164 and the boat 166.
Although the hydraulic chamber 1 is connected to the pump passage 74 by
When the control hydraulic pressure of the regulator 46 is supplied to 68,
The buffer chamber 154 is moved to the forward end shown in FIG.
to the reservoir 50 via the liquid passage 164 and the boat 170.
It communicates with In addition, the night room 172 is
-174, it is constantly in communication with the reservoir 50.

In this embodiment as well, the liquid discharged from the pump 76 at the time of startup is absorbed into the buffer chamber 154, and is returned to the reservoir 50 by switching the drain valve 158 by the controlled hydraulic pressure of the regulator 46 when the brake is applied. Thereby, the effect of reducing the starting load of the pump motor 80 can be obtained.

Several embodiments of the present invention have been described in detail above, but
In addition to these, there are various modifications of τ that are within the knowledge of those skilled in the art.
It goes without saying that the invention can be practiced in modified forms.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing a pump start-up load reduction type hydraulic brake device which is an embodiment of the present invention. 2 to 4 are diagrams schematically showing different operating states of the buffer and drain valve in FIG. 1. 5th [7+] is a diagram schematically showing a buffer and an IJY liquid valve in another embodiment of the present invention, and FIG. FIG. 7 is a diagram schematically showing a buffer and exhaust valve 11"ν in another practical example of the present invention, and FIG. 8 is a diagram showing its different operating states. 12; Master cylinder 20: Hydraulic pressure control device 22: Rear wheel cylinder 10: Solenoid valve for pressure increase/decrease switching 421' Solenoid valve for emergency control 46: Regulator 50: Reservoir 70: High pressure accumulator

Claims (1)

[Scope of Claims] A master cylinder that generates hydraulic pressure in response to the operation of a brake operating member, a wheel cylinder that operates a brake that suppresses rotation of a wheel, and a liquid passage that connects the wheel cylinder and the master cylinder. an anti-skid control device, which is provided at a pump that pumps up liquid from the tank and supplies it to the accumulator through a pump passage equipped with a check valve; and a pump control means that controls starting and stopping of the pump so that the liquid pressure in the accumulator is within a predetermined range. and a regulator that reduces the hydraulic pressure of the accumulator to a control hydraulic pressure that increases or decreases in accordance with the increase or decrease of the hydraulic pressure of the master cylinder and supplies it to the hydraulic pressure control valve, A buffer for accommodating a working fluid at a pressure lower than that of the accumulator is provided in a portion of the pump passage closer to the pump than the check valve, and the buffer is connected to the reservoir through a reflux path, and the reflux path is always provided with a reflux path. A hydraulic brake device characterized in that a drain valve is provided which is closed and switched to a state where the reflux path is opened by receiving the controlled hydraulic pressure of the regulator.