JPH0999833A - Hydraulic brake system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assist a driver to surely apply an emergency brake when the emergency brake is necessary. SOLUTION: When a brake pedal 2 is depressed with the leg power that the input load of a booster 3 is the prescribed load or above and the input load increasing speed is the prescribed rising speed or above, an ECU 36 switches and sets the feed and discharge opening/closing valves 32, 33 to the open position II and cutoff position II for a prescribed period corresponding to the vehicle speed recognized by the vehicle speed signal based on the input load signal from an input load sensor 34. The liquid pressure of an accumulator 9 is directly fed to the power chamber of the booster 3 from a bypass passage 31 by bypassing the control valve of the booster 3. The liquid pressure of the power chamber of the booster 3 is quickly and largely increased, the output of the booster 3 is quickly increased, and an emergency brake is quickly applied with large braking force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake system for boosting the braking force by boosting the pedaling force of a brake pedal by a hydraulic booster, for example, in an automobile, and more particularly to a brake pedal for emergency braking. The present invention relates to a hydraulic brake system that activates a hydraulic booster so as to quickly reach a maximum output when the stepping operation is rapidly performed.

[0002]

2. Description of the Related Art Conventionally, in automobiles, the pedal effort of the brake pedal is boosted by a hydraulic booster in order to obtain a large braking force which cannot be obtained only by the pedal effort of the brake pedal or to reduce the pedal effort. A hydraulic braking system is used to increase the braking force.

FIG. 4 is a diagram showing an example of this conventional hydraulic brake system, and FIG. 5 is a sectional view showing a closed center type hydraulic brake booster used in this system. In the figure, 1 is a hydraulic brake system, 2 is a brake pedal, 3 is this brake pedal 2
A closed center type hydraulic brake booster (hereinafter also simply referred to as a booster) 4 which is operated by the booster to output a pedaling force, 4 is a tandem type master cylinder which is actuated by the output of the booster 3 to generate a brake fluid pressure. Reference numeral 5 is a brake cylinder that operates by brake fluid pressure from the master cylinder 4 to generate a braking force for each wheel, 6 is a reservoir that stores hydraulic fluid, and 7 is a reservoir.
Is a pump driven by the motor 8 to discharge the hydraulic fluid from the reservoir 6, 9 is an accumulator for storing the hydraulic pressure of the hydraulic fluid discharged from the pump 7, and 10 is a flow of the hydraulic fluid from the pump 7 to the accumulator 9. A check valve 11 that allows only the above, a pressure switch 11 that turns on when the hydraulic pressure of the accumulator 9 becomes a predetermined value or less and outputs a hydraulic pressure decrease signal, and a switch 12 that turns on by a hydraulic pressure decrease signal from the pressure switch 11. It is a relay that drives the motor 8.

Various closed center type boosters 3 have been proposed, and an example thereof is Japanese Utility Model Application No. Hei2-120897.
FIG. 5 shows the booster 3 disclosed in the microfilm of Japanese Utility Model Publication No. 4-76576. This booster 3
Since the detailed structure and detailed operation of the above are described in the above-mentioned microfilm, the operation will be briefly described here.

In the brake non-operating state shown in FIG. 5, the control valve 13 of the booster 3 shuts off the power chamber 14 from the accumulator 9 and is connected to the reservoir 6. In this state, when the normal brake operation is performed by depressing the brake pedal 2 with the normal pedal force, the input shaft 15 moves forward, the control valve 13 is switched, and the power chamber 1
4 is disconnected from the reservoir 6 and connected to the accumulator 9. Therefore, the hydraulic fluid of a predetermined pressure from the accumulator 9 is passed through the passages 16, 17, 18 and the control valve 13,
And to the power chamber 14 through the passages 19, 20, 21. As a result, the power piston 22 operates to generate a brake operating force that boosts the pedaling force of the brake pedal 2, and the brake operating force is output from the output shaft 23 to operate the master cylinder 4 and the brake operates.

When the brake operation is released by releasing the brake pedal 2, the input shaft 15 is retracted to the non-actuated position shown in FIG. 5 and the control valve 13 is switched, so that the power chamber 14 is shut off from the accumulator 9 and the reservoir. 6 is connected. Therefore, the hydraulic fluid in the power chamber 14 is transferred to the passages 21, 20, 19, the control valve 13, and the passages 24, 25, 26, 2.
It is discharged to the reservoir 6 through the discharge passage 7 and the discharge passage 28. As a result, the power piston 22 retracts to the non-operating position, the brake operating force disappears, the master cylinder 4 returns to the non-operating state, and the brake operation is released.

The pressure switch 11 is turned on when the hydraulic pressure of the accumulator 9 becomes a predetermined value or less, and outputs a hydraulic pressure lowering signal to the relay 12 to turn on the relay 12. As a result, the motor 8 is driven, the pump 7 is driven, and hydraulic pressure is stored in the accumulator 9. When the hydraulic pressure of the accumulator 9 exceeds a predetermined value, the pressure switch 11 turns off,
The motor 8 or pump 7 is stopped. In this way, the hydraulic pressure exceeding the predetermined value is automatically stored in the accumulator 9.

[0008]

By the way, in such a hydraulic brake system, when there is a high risk of vehicle collision and an emergency brake is required, it is necessary to fully depress the brake pedal. However, some drivers, such as beginners, who are unfamiliar with driving a vehicle cannot fully depress the brake pedal until the maximum braking force is reached when an emergency brake is required. For this reason, such a driver may not be able to reliably apply the emergency brake when the emergency brake is required.

The present invention has been made in view of such circumstances, and an object thereof is to provide a hydraulic brake for assisting a driver so that the emergency brake can be reliably applied when the emergency brake is required. It is to provide a system.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 provides a reservoir for storing a working fluid,
A pressure source that generates a hydraulic pressure of a predetermined pressure using the hydraulic fluid in the reservoir, a brake operating member, an input shaft that advances by the operation of the brake operating member, and the hydraulic fluid of the pressure source during brake operation are supplied. The power chamber is configured to supply the hydraulic fluid from the pressure source to the power chamber by advancing the input shaft, and to discharge the hydraulic fluid in the power chamber to the reservoir through a discharge passage by retracting the input shaft. A control valve for controlling the supply and discharge of the working fluid with respect to the chamber, a power piston that is operated by the hydraulic pressure of the working fluid in the power chamber,
And a hydraulic booster each having an output shaft that outputs by the operation of the power piston, a master cylinder that operates by the output of the output shaft of the hydraulic booster to generate brake hydraulic pressure, and the master cylinder. And a brake cylinder that generates a braking force when the brake hydraulic pressure is supplied to the brake operating member to boost the operating force of the brake operating member to obtain a large braking force. A bypass passage connecting the pressure source and the power chamber by bypassing the control valve of the device, a normally closed supply opening / closing valve provided in the bypass passage, and a normally open discharge provided in the discharge passage. Open / close valve for
Brake operating force detecting means for detecting a brake operating force of the brake operating member, and the brake operating force is equal to or more than a predetermined operating force based on a brake operating force signal from the brake operating force detecting means and And a controller that operates the supply and discharge on-off valves so that the discharge on-off valve is closed and the supply on-off valve is opened when the rising speed is determined to be equal to or higher than a predetermined rising speed. The hydraulic fluid from the pressure source is also supplied to the power chamber from the bypass passage during an emergency brake operation.

The present invention further comprises a vehicle speed sensor for detecting the vehicle speed, and the control device sets the supply and discharge on-off valves to the vehicle speed based on the vehicle speed signal from the vehicle speed sensor. It is characterized in that the operation is controlled for a predetermined time according to the above.

Further, in the invention of claim 3, the control device is
After the brake operation, when it is determined that the vehicle has stopped based on the vehicle speed signal from the vehicle speed sensor, the discharge on-off valve is operated and closed.

Further, the invention of claim 4 further comprises a starting operation detecting means for detecting an operation of a starting operation means for starting the vehicle, wherein the control device holds the discharge on-off valve in an operating state after the vehicle is stopped. The discharge on-off valve is opened based on the vehicle start operation signal from the start operation detecting means during the operation.

According to a fifth aspect of the present invention, the control device comprises:
When the discharge on-off valve is held in an operating state after the vehicle is stopped, when the vehicle start operation signal from the start operation detecting means is not input and the vehicle speed signal from the vehicle speed sensor is input, It is characterized in that the supply on-off valve is opened.

[0015]

In the present invention having such a configuration, the control device determines that the brake operating force is equal to or higher than the predetermined operating force and the increasing speed of the brake operating force is equal to or higher than the predetermined increasing speed based on the brake operating force signal. When judged, the discharge on-off valve is closed and the supply on-off valve is opened. As a result, the hydraulic fluid from the pressure source is supplied to the power chamber from the bypass passage as well, and the hydraulic pressure in the power chamber rises rapidly, so the output of the hydraulic booster rapidly increases and the braking force is increased. Works quickly. Therefore, even if the brake operating member is not rapidly and largely operated, the emergency brake can be reliably operated.

Particularly, in the invention of claim 2, the control device operates the supply and discharge on-off valves for a predetermined time according to the vehicle speed. As a result, the emergency brake operates for a time period corresponding to the vehicle speed, and the emergency brake operates more appropriately.

In the third aspect of the invention, when the vehicle stops due to a brake operation such as a normal brake and the vehicle speed becomes zero, the control device closes the discharge on-off valve. This allows
When the vehicle is stopped, the brake remains in the activated state, and the vehicle is held in the stopped state where the vehicle cannot start. As a result, the vehicle stop braking can be reliably and automatically performed.

Further, in the invention of claim 4, when the vehicle starting operation is performed by the starting operation member while the vehicle is held in the stopped state, the control device opens the discharge on-off valve. As a result, the brake in the operating state is released,
The vehicle is released from the stopped state and is ready to start. This facilitates a starting operation such as starting on a slope.

Further, in the invention of claim 5, the vehicle speed signal is input from the vehicle speed sensor while the vehicle is held in a stopped state, even though the vehicle start operation is not performed by the start operation member. Then, the control device opens the supply opening / closing valve for a predetermined time. Therefore, the hydraulic pressure in the power chamber of the hydraulic booster increases, the braking force increases, and the vehicle is reliably held in the stopped state. As a result, it is possible to prevent unintentional movement of the vehicle while the vehicle is held in a stopped state on a slope, for example.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first hydraulic brake system according to the present invention.
4 is a circuit diagram showing an embodiment similar to FIG. 4, and FIG. 2 is a partially enlarged sectional view of a booster 3 used in this embodiment. The conventional hydraulic brake system shown in FIG. 4 and the conventional hydraulic brake system shown in FIG.
The same components as those of the booster 3 shown in FIG.

As shown in FIGS. 1 and 2, in the first embodiment, the passage 2 through which the booster 3 always communicates with the power chamber 14.
9 is provided, and the passage 29 is connected to a position of the supply passage 30 connecting the accumulator 9 and the passage 16 of the booster 3 on the downstream side of the accumulator 9. That is, the accumulator 9 and the power chamber 14 are
It is directly connected by a bypass passage 31 that bypasses the control valve 13.

The bypass passage 31 is provided with a normally-closed supply on-off valve 32 which is an electromagnetic valve provided with two positions, a shut-off position I and a communication position II. A normally open discharge on-off valve 33, which is an electromagnetic valve provided at two positions, a communication position I and a shut-off position II, is provided. Further, the input shaft 15 is provided with an input load sensor 34 that detects an input load (a load corresponding to the pedal effort) applied to the input shaft 15 when the brake pedal 2 is depressed, and at an appropriate place of the vehicle. A vehicle speed sensor 35 that detects the vehicle speed is provided.

The supply on-off valve 32, the discharge on-off valve 33, the input load sensor 34 and the vehicle speed sensor 35 are all connected to an electronic control unit (hereinafter also referred to as ECU) 36. This ECU 36 is for supplying and discharging when the input load is equal to or higher than a predetermined load and the input load rising speed obtained by differentiating the input load is equal to or higher than the predetermined rising speed based on the input load signal from the input load sensor 34. On-off valve 3
2, 33 are operated for a predetermined time and set to position II. In that case, the predetermined time, which is the operating time of the supply and discharge on-off valves 32 and 33, is set to increase as the vehicle speed increases, based on the vehicle speed signal from the vehicle speed sensor 35. As a result, the emergency brake can be applied according to the vehicle speed. Other configurations of the first embodiment are the same as those of the conventional hydraulic brake system and booster shown in FIGS. 4 and 5.

The operation of the first embodiment thus constructed will be described. When the brake is not operated, the supply and discharge on-off valves 32 and 33 and the booster 3 of the hydraulic brake system 1 are in the states shown in FIGS. 1, 2 and 5, that is, the same state as the conventional hydraulic brake system 1. Has become.

While the vehicle is running with the brake not operated,
When the normal brake operation is performed by depressing the brake pedal 2 with the normal pedal effort, the ECU 36 receives the vehicle speed signal from the vehicle speed sensor 35 and the input load signal from the input load sensor 34. At this time, since the pedal effort is a normal pedal effort, the input load is smaller than the predetermined load. The ECU 36
Based on this input load signal, the input load is recognized to be smaller than the predetermined load, it is determined that the brake operation is normal, and both the supply and discharge on-off valves 32 and 33 are held at the position I shown in FIG. . This state is the same as that of the conventional hydraulic brake system described above, and therefore the operation of the first embodiment during normal brake operation is the same as the operation of the conventional hydraulic brake system 1 during normal brake operation described above. Is.

If the brake pedal 2 is rapidly depressed with a pedal effort much greater than the pedal effort during normal braking while the vehicle is running in the brake-unoperated state and emergency braking operation is performed, it is far more than during normal braking. A large input load signal is input to the ECU 36. At this time, the pedal effort is much larger than that during normal braking, the input load is equal to or higher than the predetermined load, and the input load rising speed is equal to or higher than the predetermined rising speed. ECU 36
Recognizes that the input load is equal to or higher than the predetermined load and the input load rising speed is equal to or higher than the predetermined rising speed based on the input load signal, and determines that the emergency braking operation is performed. And
The ECU 36 switches and sets the supply and discharge on-off valves 32 and 33 to the communication position II and the cut-off position II for a predetermined time according to the vehicle speed recognized based on the vehicle speed signal.

As a result, the hydraulic pressure of the accumulator 9 is also supplied from the bypass passage 31 directly to the power chamber 14 bypassing the control valve 13. In that case, since the discharge on-off valve 33 is set to the shutoff position II, the power chamber 14 is shut off from the reservoir 6, so that the hydraulic pressure supplied to the power chamber 14 does not leak to the reservoir 6. Absent. Therefore, the hydraulic pressure in the power chamber 14 increases rapidly and greatly, so that the output of the booster 3 rapidly increases and the emergency brake operates quickly with a large braking force.

When a predetermined time has elapsed after the switching setting of the supply and discharge on-off valves 32 and 33 to the position II, the ECU 3
Reference numeral 6 switches the supply and discharge on-off valves 32 and 33 to the shut-off position I and the communication position I, respectively. At this time, even if the discharge on-off valve 33 is switched to the communication position I, the passage 19 and the passage 24 are shut off by the control valve 13 that is in an activated state by depressing the brake pedal 2, so that the power chamber 14 is It is shut off from the reservoir 6. The power chamber 14 is also shut off from the accumulator 9.
Therefore, the supply of hydraulic fluid to the power chamber 15 is stopped, and the power chamber 15 has a hydraulic pressure corresponding to the vehicle speed. As a result, the braking force in the emergency brake is adjusted according to the vehicle speed.

When the brake pedal 2 is released, the control valve 1
3 is switched to the non-operating state shown in FIG. 5, and the passage 19 and the passage 24 communicate with each other. Therefore, the hydraulic fluid in the power chamber 14 is discharged to the reservoir 6 and the brake is released, as in the case of the normal brake described above.

Thus, the first embodiment has the emergency brake actuation function, and the emergency brake can be surely actuated even if the brake pedal 2 is not rapidly depressed greatly. In that case, the emergency brake operates properly according to the vehicle speed.

FIG. 3 shows a second embodiment of the present invention, which is shown in FIG.
It is a circuit diagram similar to. The same components as those in the above-described first embodiment and the conventional hydraulic brake system are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 3, in the second embodiment, an accelerator switch 37 is further provided in the first embodiment described above, and this accelerator switch 37 is connected to the ECU 36. The accelerator switch 37 is turned on by depressing an accelerator pedal (not shown) and outputs an accelerator operation signal to the ECU 36.

When the ECU 36 determines that the vehicle speed has become 0 due to the normal brake operation and the vehicle speed has become 0 based on the vehicle speed signal from the vehicle speed sensor 35, the ECU 36 sets the discharge on-off valve 33 to the shut-off position II. It is supposed to do. As a result, the brake is maintained in the activated state when the vehicle is stopped. Further, the ECU 36 switches and sets the discharge on-off valve 33 to the communication position I based on the accelerator operation signal from the accelerator switch 37. This releases the brake operation hold when the vehicle is stopped so that the vehicle can start. The other structure of the second embodiment is the same as that of the first embodiment.
As described above, the second embodiment has a vehicle stop holding function in addition to the emergency brake actuation function of the first embodiment.

The operation of the second embodiment will be described.
In the second embodiment, when the vehicle stops due to the normal brake operation and the vehicle speed becomes 0, the ECU 36 causes the vehicle speed sensor 3
The vehicle speed signal from 5 is no longer input. The ECU 36 determines that the vehicle is stopped and switches the discharge on-off valve 33 to the shutoff position II. Therefore, even if the brake pedal 2 is released and the control valve 13 is switched to the inoperative state shown in FIG. 5, the power chamber 14 is shut off from the reservoir 6. Therefore, the hydraulic fluid in the power chamber 14 is contained and the booster 3
Is kept active. That is, after the vehicle is stopped,
The brake is maintained in the activated state, and the vehicle is held stationary.

When the driver depresses the accelerator pedal to start the vehicle while the vehicle is stopped and held, the accelerator switch is turned on and an accelerator operation signal is output to the ECU 36.
The ECU 36 switches the discharge opening / closing valve 33 to the communication position I in response to the accelerator operation signal to connect the power chamber 14 to the reservoir 6. As a result, the hydraulic fluid in the power chamber 14 is discharged to the reservoir 6 as described above, so that the brake is released from the vehicle, the vehicle is released from the stopped state, and the vehicle can start. The other operation of the second embodiment is the same as that of the first embodiment.

In the second embodiment, the ECU 36
When the vehicle speed increases and the vehicle speed signal is input from the vehicle speed sensor 35 even though the accelerator switch 37 is off and the accelerator operation signal is not input from the accelerator switch 37 while the vehicle is held stationary, the supply opening / closing The valve 32 may be switched to the communication position II for a predetermined time. As a result, it is possible to prevent unintentional movement of the vehicle, such as sudden movement of the vehicle when the vehicle is stopped on a slope.

In each of the above-described embodiments, the input load is detected by the input load sensor 34 provided on the input shaft 15. However, in the present invention, instead of the input load by the input load sensor 34, the brake pedal 2 is used. It is also possible to use the pedal effort detected by the pedal effort sensor provided in the. Further, the pedal stroke speed of the brake pedal 2 can be used instead of the input load increasing speed in each of the above-described embodiments.

[0038]

As is apparent from the above description, according to the hydraulic brake system of the present invention, the hydraulic fluid from the pressure source is bypassed from the control valve of the hydraulic booster during the emergency braking operation by the driver. Since the power is supplied directly to the power room, a large braking force can be obtained quickly.
Therefore, even if the brake operating member is not rapidly and largely operated, the driver can be assisted to reliably operate the emergency brake.

According to the second aspect of the invention, since the emergency brake is operated for a time period corresponding to the vehicle speed, the emergency brake can be operated more appropriately.
Further, according to the invention of claim 3, when the vehicle is stopped, the brake can be kept in the operating state and the vehicle can be held in the stopped state where the vehicle cannot start. As a result, the parking brake can be reliably and automatically applied.

Further, according to the invention of claim 4, the vehicle is released from the stopped state by performing the vehicle start operation while the vehicle is held in the stopped state. The vehicle can be ready to start. This makes it easy to perform a starting operation such as starting on a slope.

According to the fifth aspect of the present invention, the braking force is increased when the vehicle starts moving while the vehicle is held stationary and the vehicle is not started. Therefore, the vehicle can be reliably held in the stopped state. As a result, it is possible to prevent unintentional movement of the vehicle when the vehicle is held in a stopped state on a slope, for example.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a hydraulic brake system according to the present invention.

FIG. 2 is a partially enlarged sectional view of a hydraulic booster used in the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing an example of a conventional hydraulic brake system.

FIG. 5 is a sectional view showing an example of a conventional closed center type brake booster used in the present invention.

[Explanation of symbols]

1 ... Hydraulic boosting system for vehicle, 2 ... Brake pedal, 3
… Closed center type hydraulic brake booster, 4… Master cylinder, 5… Brake cylinder, 6…
Reservoir, 7 ... Pump, 8 ... Motor, 9 ... Accumulator, 10 ... Check valve, 11 ... Pressure switch, 12
... relay, 13 ... control valve, 14 ... power chamber, 15 ... input shaft, 16,17,18,19,20,21,24,25,26,
27 ... passage, 22 ... power piston, 23 ... output shaft, 2
8 ... Discharge passage, 29 ... Passage, 30 ... Supply passage, 31 ... Bypass passage, 32 ... Supply on-off valve, 33 ... Discharge on-off valve, 34 ... Input load sensor, 35 ... Vehicle speed sensor, 36 ...
Electronic control unit (ECU), 37 ... Accelerator switch 37

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[Procedure amendment]

[Submission date] October 18, 1995

[Procedure Amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

[Fig. 2]

[Procedure 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

[Figure 3]

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

Claims (5)

[Claims] 1. A reservoir for storing a hydraulic fluid, and a pressure source for generating a hydraulic pressure of a predetermined pressure by using the hydraulic fluid in the reservoir.
A brake operating member, an input shaft that moves forward by operating the brake operating member, a power chamber to which hydraulic fluid of the pressure source is supplied during brake operation, and a hydraulic chamber that supplies the hydraulic fluid from the pressure source to the power chamber by advancing the input shaft. And a control valve for controlling the supply and discharge of the working fluid to and from the power chamber so that the working fluid in the power chamber is discharged to the reservoir through a discharge passage by retreating the input shaft. A hydraulic booster having a power piston operated by the hydraulic pressure of the hydraulic fluid and an output shaft output by the operation of the power piston, and a brake fluid operated by the output of the output shaft of the hydraulic booster. A master cylinder that generates a pressure; and a brake cylinder that generates a braking force when the brake fluid pressure of the master cylinder is supplied. In a hydraulic brake system that boosts the operating force of a brake operating member to obtain a large braking force, further, a bypass passage that bypasses a control valve of the hydraulic booster and connects the pressure source and the power chamber. A normally closed supply opening / closing valve provided in the bypass passage, a normally opening discharge opening / closing valve provided in the discharge passage, and a brake operating force detecting means for detecting a brake operating force of the brake operating member. And when it is determined that the brake operating force is equal to or higher than a predetermined operating force and the increasing speed of the brake operating force is equal to or higher than a predetermined increasing speed based on the brake operating force signal from the brake operating force detecting means, the discharge is performed. A control device that operates each of the supply and discharge on-off valves so that the supply on-off valve is opened and the supply on-off valve is opened. Hydraulic brake system, characterized in that also supplied to the power chamber of the hydraulic fluid from the serial pressure source from said bypass passage. 2. A vehicle speed sensor for detecting a vehicle speed is further provided,
2. The hydraulic brake according to claim 1, wherein the control device controls the operation of the supply and discharge opening / closing valves for a predetermined time period according to the vehicle speed based on a vehicle speed signal from the vehicle speed sensor. system. 3. The control device operates and closes the discharge on-off valve when it is determined that the vehicle has stopped based on a vehicle speed signal from the vehicle speed sensor after a brake operation. The hydraulic brake system according to 1 or 2. 4. The vehicle further comprises a starting operation detecting means for detecting an operation of a starting operation means for starting the vehicle, wherein the control device is configured to: when the discharge on-off valve is held in an operating state after the vehicle is stopped, 4. The hydraulic brake system according to claim 3, wherein the discharge on-off valve is opened based on a vehicle start operation signal from the start operation detection means. 5. The control device, when the discharge on-off valve is held in an operating state after the vehicle is stopped, the vehicle start operation signal from the start operation detecting means is not input, and the vehicle speed sensor outputs the vehicle speed sensor. 5. The hydraulic brake system according to claim 4, wherein the supply opening / closing valve is opened when the vehicle speed signal is input.