JP2000001162A - Hydraulic brake unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit pressure increase/decrease control of the brake cylinder with the operation of the pump in a hydraulic brake unit equipped with pump. SOLUTION: A pump 44 for low pressure is a gear pump. A motor 50 for low pressure which is rotatable in the positive and reverse directions is connected to the pump 44 for low pressure. Rotational direction of the pump 44 for low pressure is controlled by the motor 50 for low pressure. If the pump 44 for low pressure is rotated to one direction, hydraulic fluid in a master reservoir 30 is sucked by the pump 44 for low pressure and is discharged to be supplied to wheel cylinders 18, 24, 36, 38. The wheel cylinder hydraulic pressure is thus increased. If the pump for low pressure is rotated to the other direction, hydraulic fluid in the wheel cylinders 18, 24, 36, 38 is made to flow out and return to the master reservoir 30 through the pump 44 for low pressure. The wheel cylinder hydraulic pressure is thus decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake device for operating a brake by a hydraulic fluid discharged from a pump.

[0002]

2. Description of the Related Art An example of the above-described hydraulic brake device is described in Japanese Patent Application Laid-Open No. 9-256960. The hydraulic brake device described in this publication includes a brake cylinder and a brake hydraulic pressure control device, and the brake cylinder operates the brake by the hydraulic pressure of the hydraulic fluid. Also, the brake fluid pressure control device includes two pumps connected in parallel with each other, and a pump device connected to the brake cylinder;
A pump device control device that controls the hydraulic pressure of the brake cylinder by controlling the rotation states of two pumps included in the pump device. In this hydraulic brake device, the hydraulic fluid discharged from at least one of the two pumps is supplied to the brake cylinder to increase the pressure. By selectively switching each of the two pumps between an operating state and a non-operating state, an independent pressure increasing state in which the hydraulic fluid discharged from one pump is supplied to the brake cylinder, and a hydraulic pump discharged from each of the two pumps The state is switched to a common pressure increase state in which the hydraulic fluid is supplied, whereby the flow rate of the hydraulic fluid flowing into the brake cylinder is controlled. However, in the hydraulic brake device described in this publication, the hydraulic fluid in the brake cylinder is not discharged through a pump to reduce the pressure.

[0003]

Problems to be Solved by the Invention, Means of Solution, Functions and
Effect] The present invention not only increases the brake cylinder pressure but also reduces it.
It is necessary to obtain a hydraulic brake device whose pressure can be controlled by a pump.
The present invention has been made with
The hydraulic brake device of each of the above aspects is obtained. In addition, each aspect
Is divided into sections, numbered, and other sections as necessary.
Refer to the number of the section and write it in the same format as the claim. Each term
Clarifies the possibility of adopting a combination of the features described in
To show. (1) A brake that activates the brake by hydraulic fluid pressure
Control the hydraulic pressure of the key cylinder and its brake cylinder
A hydraulic brake device including a brake hydraulic pressure control device.
The brake fluid pressure control device
At least one pump connected to the
Discharge from at least one of at least one pump
Pressure supply to supply the hydraulic fluid to the brake cylinder
And at least one of the at least one pump
Reduce hydraulic fluid drain from brake cylinder via one
A pump device that can be selectively switched to a pressure state,
At least controlling the rotational state of the at least one pump.
Control the hydraulic pressure of the brake cylinder
And a pump device control device.
A storage device (Claim 1). If the pump device is under pressure
The hydraulic fluid discharged from the pump
And the hydraulic pressure of the brake cylinder is increased.
If the pump device is in a reduced pressure state,
The hydraulic fluid in the pump is discharged through a pump and is depressurized. this
Thus, in the hydraulic brake system described in this section,
The pump operation does not only increase the brake cylinder fluid pressure.
Also reduced pressure is applied. The pump device comprises at least one pump.
Pump, and only one pump is included.
May be two or more. Also, in addition to the pump direction
It may include a switching valve and the like. Included in pump device
If only one pump is used,
Switching between increased pressure state and reduced pressure state by switching
Possible or the direction of rotation is constant
Can be switched between increased pressure and reduced pressure by
can do. For example, if the pump device is a gear pump
If included, the rotation direction of the gear pump
If changed, discharge hydraulic fluid to brake cylinder side
When the pressure is increased, hydraulic fluid is sucked in from the brake cylinder side
The state is switched to the reduced pressure state. In addition, the pump is
And a reciprocating pump with a discharge valve.
The discharge direction is constant regardless of the rotation direction of the driving shaft
In this case, the operation of the directional control valve
Connected to the discharge side of the pump and to the suction side.
Is switched to a reduced pressure state. In this case, the pump
Any of pumps, plunger pumps, vane pumps, etc.
It may be. Two pumps included in the pump device
In some cases, for example, one pump is dedicated to boosting pressure and the other is
Pump can be dedicated to decompression. Decompression only pon
Pump is stopped, and the booster pump is
If this occurs, the pump device will be in the boosted state,
Is stopped, and the vacuum pump is turned on.
Then, the pressure is reduced. Also, one of the pumps is
Pump and the other pump is operated by the brake cylinder
The pressure increase state where the liquid is supplied and the pressure decrease state where the hydraulic fluid flows out
Or a pump that can be switched between
(Including those that can be switched by operating a switching valve)
Pump is dedicated to decompression, and the other pump is
Use both a decompression pump and both pumps
Or a pump for Pump equipment increased
Including a dedicated pump for pressure control and a pump for both pressure increase and pressure reduction
Are both pumps dedicated to boosting pressure and pumps for both
Is activated, a large flow to the brake cylinder
Hydraulic fluid can be supplied.
If the pump is in operation and the booster pump is stopped,
The hydraulic fluid can flow out of the storage cylinder. Ma
In addition, as explained in section (4), a pump
High pressure small capacity type with small maximum discharge volume and large maximum discharge pressure
The pump has a maximum discharge pressure that is small
When using a low-pressure large-capacity pump with a large maximum discharge rate
, The pump for increasing and decreasing pressure is activated during normal braking
The emergency pump is in operation.
If the brake cylinder pressure was increased during normal braking
Pressure (hereinafter simply referred to as brake cylinder pressure increase or
(Referred to as pressure reduction).
The pressure can be increased to a reasonable level. Includes two pumps
The maximum discharge pressure and maximum discharge of each of the two pumps
Even if the pump capacity such as volume is the same,
It is good also as. If different, hydraulic control
The range can be widened and the degree of freedom of control can be increased
Can be. As described above, the pump device control device
Rotation, stop, rotation direction, rotation of pump included in pump device
It controls the rotation state such as speed.
Includes a directional control valve,
Also controls the directional control valve. Control the pump rotation speed
Per unit time within the range not exceeding the maximum discharge rate
The discharge rate of the brake cylinder to increase or decrease the brake cylinder pressure
The degree can be controlled. Below, included in the pump device
Control the rotational state of one or more pumps, directional control valves, etc.
This is simply referred to as controlling the pump device. What
The pump device shall include three or more pumps.
The combination of three or more pumps is
The pump device can be switched between the increased pressure state and the reduced pressure state.
Pump for exclusive use of pressure increase, pump for exclusive use of pressure reduction, both use for pressure increase and pressure reduction
One or more pumps Combination of three or more pumps
You. (2) A brake that activates the brake by the hydraulic fluid pressure
Control the hydraulic pressure of the key cylinder and its brake cylinder
A hydraulic brake device including a brake hydraulic pressure control device.
The brake fluid pressure control device
At least one pump connected to the
At least one rotary of at least one pump
The hydraulic fluid to the brake cylinder by controlling the
When the pressure is increased and the hydraulic fluid flows from the brake cylinder
Pump device that can be selectively switched to a reduced pressure
And controlling the rotational state of the at least one pump.
Control the hydraulic pressure of the brake cylinder
And a pump device control device.
Device. In the hydraulic brake device described in this section,
The pump device includes one or more pumps. Pump included
If there is only one, switch the rotation direction of the pump
Thus, the pressure can be switched between the increased pressure state and the reduced pressure state. pump
For example, a gear pump can be adopted. included
In case of two pumps, as described in paragraph (1)
And a pump exclusively for pressure increase and a pump exclusively for pressure reduction.
One of the pumps dedicated to increasing pressure and the pumps dedicated to reducing pressure.
And two pumps
Including a pump for both pressure increase and pressure reduction
it can. In this aspect, one or more pumps
Switching between the pressure increasing state and the pressure reducing state
Therefore, the pump device includes a directional control valve,
Switching between increased pressure state and reduced pressure state by valve control
Is not scheduled. However, separate from the pump device
A control valve device is provided to increase and decrease pressure by the pump device.
Increase or decrease pressure for antilock control, etc.
Is not excluded. (3) The pump device includes a plurality of the brake cylinders.
And the hydraulic pressures of the brake cylinders are shared.
Hydraulic brake as described in paragraph (1) or (2)
Apparatus (Claim 2). Multiple brake syringes in pump device
When the pump is connected, multiple brakes can be controlled by the pump device.
It is possible to control the hydraulic pressure of the
You. Exclusive pump device for each brake cylinder or
Hydraulic pressure control valve devices are installed and they are
To control the brake cylinder hydraulic pressure
Has multiple brake cylinders due to control variation
It is inevitable that there will be a hydraulic pressure difference between
The hydraulic brake device described in
Control of multiple brakes connected to the pump device
Because the cylinder pressure is controlled, multiple brake
Can easily control the hydraulic pressure of the
You. (4) Two pump devices connected in parallel with each other
Pumps, one pump being more simple than the other.
Large maximum discharge volume per unit time and low maximum discharge pressure
Switching of the rotation direction of one of the pumps
The pump device transfers hydraulic fluid to the wheel cylinder
Pressure from the wheel cylinder and suction from the wheel cylinder
(1) to (3)
The hydraulic brake device according to claim 1 (claim 3). Book
Pump equipment included in the hydraulic brake system described in section
Including two pumps connected in parallel,
One of the pumps is a pressure increasing / decreasing pump. Pressure increase / decrease
Pressure pumps have a large maximum discharge rate per unit time.
This is a low-pressure large-capacity pump with a small maximum discharge pressure. low pressure
Rotation direction of large-capacity pump for both pressure increase and pressure reduction is switched
The pump device is in the pressure increasing state and the pressure reducing state.
Is switched to Low pressure and large capacity type
For example, a gear pump can be adopted as the pump.
Switch the rotation direction of two gears in a gear pump
If the pressure is increased, hydraulic fluid is discharged to the brake cylinder
And a decompression state in which hydraulic fluid is sucked in from the brake cylinder side
Switch to The gap between the two gears,
Use the leak from the gap with the body to use the brake cylinder
Out of the hydraulic fluid, which can be used as a form of decompression.
It is possible. The maximum discharge rate per unit time depends on the pump and
It depends on the motor that drives the pump. Unit time
The discharge amount per interval is large when the discharge amount per rotation is large.
If the rotation speed is high
Is larger than when smaller. Discharge volume per rotation
Is determined by the structure of the pump.
It depends on the design of the motor and other factors. The maximum discharge rate is
The discharge rate when rotating at the upper limit rotation speed.
The rotation rate should not exceed the maximum discharge rate.
It can be controlled by controlling the speed. Maximum discharge pressure of pump
Is determined by the set pressure of the relief valve connected to the pump.
Often round. Pump discharge pressure is greater than set pressure
Overload and pump and motor loads become excessive
That is avoided. Pump device is low pressure and large capacity type
Including low-pressure pump
The flow rate of hydraulic fluid flowing into the brake cylinder can be increased,
For example, when the operation of the brake
Delay can be reduced. Also, the hydraulic pressure of the brake cylinder
Is not so large, that is, during normal braking,
It is possible to increase or decrease the pressure of the brake cylinder
The brake cylinder hydraulic pressure
It becomes possible to control the size. For example, brake equipment
The deceleration of a vehicle equipped with a brake
Braking effect to control the size according to the operation force of the material
It is possible to execute the result control. The other port
Pump has a larger maximum discharge pressure than one pump
Although it is a high-pressure small-capacity pump with a small output,
Increases pressure as both a pressure pump and a decompression pump
A dedicated pump may be used. However, one pump is boosted
・ Because it is a pressure reducing pump, it should be a pump exclusively for increasing pressure.
Is desirable. As described above, during normal braking, low pressure
The operation of the capacity-type pressure increasing / reducing pumps
Control the hydraulic pressure of the
When the brake operation member is operated with (Brake cylinder
If the required hydraulic pressure is large),
Brake cylinders are often not considered a problem.
There is almost no need to control the pressure reduction of the
Often. Therefore, the pressure of the high-pressure small-capacity pump is increased / decreased.
There is little need to use a pressure-multiplying pump.
I just need to. Examples of high-pressure small-capacity pumps
For example, a plunger pump is suitable. In this way,
The pump unit is a low-pressure large-capacity type
In the case that the pump includes a low pressure type pump
Reduces the effect delay at the start of braking, etc.
Brake force can be controlled by a pump
And can generate large braking force
Becomes One high pressure and large capacity type pump device
Similar effects can be obtained even if a pump is included.
However, high-pressure large-capacity pumps are expensive and large.
You. Therefore, in the hydraulic brake device described in this section,
As shown, low-pressure large-capacity pressure booster / reducer pump and high-pressure small capacity pump
If a pump dedicated to boosting pressure is included, cost reduction and
And downsizing can be achieved. Strictly speaking,
Pump brake fluid pressure is reduced at high pressure
However, as described above, high pressure
Since there is almost no need to control the pressure reduction during
It is not necessary to use a pump
You. (5) Two pump devices connected in parallel with each other
Pumps, one pump being more simple than the other.
Large maximum discharge volume per unit time and low maximum discharge pressure
Which is described in any one of paragraphs (1) to (3).
Hydraulic brake device. The hydraulic brake device described in this section
The pump unit consists of a high-pressure small-capacity pump and a low-pressure large-capacity pump.
And One of these two pumps
Is a dedicated pump for pressure increase, and the other is a dedicated pump for pressure reduction.
At least one of which is a pump for
Can be For example, increasing the pressure of a high-pressure small-capacity pump
If a pressure reducing pump is used, the brake cylinder
Pressure can be reduced,
Ensure that the braking effect according to the operating force is obtained
Becomes possible. (6) The pump device is connected to the brake cylinder
Pressure can be reduced to allow hydraulic fluid to flow out of the brake cylinder.
Pump and its decompressible pump and brake cylinder
Is provided in the middle of the liquid passage connecting the
Communication between the brake and the cylinder,
Block the flow of hydraulic fluid from the
An outflow prevention valve that can be switched to an outflow prevention state that stops
The hydraulic pressure according to any one of paragraphs (1) to (5), including
Brake device. Outflow check valve is electrically connected and outflow
Even if it is an electromagnetic switching valve that can be switched to the blocking state,
Pilot type that switches based on the discharge pressure of the pump device
It may be a switching valve. In addition, the outflow check valve is
Including the spool valve, but also including the spool valve
You may. If the seating valve is included,
The pressure can be reduced from the brake cylinder in the outflow prevention state.
Hydraulic fluid can be completely prevented from flowing to the pump,
If a valve is included, even if the outflow prevention state is set,
A slight outflow of hydraulic fluid due to leakage cannot be avoided. Outflow prevention
The condition is the dual between the brake cylinder and the vacuum pump.
In the two-way flow blocking state that blocks the flow of hydraulic fluid in
Even from the decompressible pump to the brake cylinder actuation
Liquid flow may be in one-way flow blocking condition
No. In any case, the pressure can be reduced from the brake cylinder
The flow of the hydraulic fluid to the pump can be prevented. Decompression
Possible pump drains hydraulic fluid from brake cylinder
Can be supplied but cannot be supplied
Pressure booster / decompressor pump that can supply and discharge
Pump (also called a pump that can increase or decrease pressure)
You may. If the pump is exclusively for decompression,
In addition to the decompressible pump,
A pump that can supply hydraulic fluid will be provided.
You. In any case, the outflow prevention valve is in the outflow prevention state
In this case, from the brake cylinder through the decompressible pump
The hydraulic fluid can be prevented from flowing out, and the brake
The cylinder can be prevented from being depressurized. Sa
This will be described in more detail. Brake cylinder and decompressible pump
If there is no outflow prevention valve between
That is, when the communication is always established, the brake cylinder side
The pump is a motor based on the hydraulic pressure difference between the pump and the reservoir.
Reverse drive torque acts in the direction
Drive source such as an electric motor that drives the pump with reverse drive torque
If it is larger than the driving torque or static torque of
This happens when the available pump is for low pressure
), The pump is actually turned in the opposite direction and the hydraulic fluid
Flows to the reservoir side to increase and maintain the brake cylinder pressure.
(Hydraulic pressure holding) cannot be performed. Drive torque and static
Stop torque is large enough, or pump and drive source
Between the worm and the worm wheel
Allows the drive source to rotate from the pump side as if
If a reverse drive blocking device that does not
High flow to the reservoir is prevented, but the pump
If the structure cannot completely prevent leakage,
Due to the leak, some hydraulic fluid flows to the reservoir side,
Brake cylinder decompression or energy loss occurs
You. If the decompressible pump is for low pressure,
If pressure acts, the pump may be damaged. Against it
Then, as in this embodiment, the outflow prevention valve is provided to
Switching to the blocking state prevents the above various situations from occurring
You can do it. The outflow prevention valve is
Even if it includes a spool valve, it also includes a spool valve.
Even if there is a rotation of the pump due to the above reverse drive torque
A large flow of the hydraulic fluid to the reservoir side can be prevented. Flow
The outflow prevention valve includes a seating valve to prevent leakage.
If this is the case, the hydraulic fluid is
Blocking the flow to the server side or the pump
Can be prevented from being more damaged or
You. (7) The pump device includes the brake cylinder
Connected in parallel with the decompressible pump and connected to the brake cylinder
Including (6) including a pressure boostable pump that can supply hydraulic fluid
Hydraulic brake equipment. The boostable pump is
Pressure booster port that does not allow hydraulic fluid to flow out of the
Pumps that can be drained from pumps
Pump may be used. The pump that can be decompressed is
Pump, and the booster pump is a pump exclusively for booster
If the outflow check valve is in communication with the
Activate the dedicated pump and the decompression dedicated pump alternatively.
If the brake cylinder hydraulic pressure is increased or decreased
Can be Decompression when in the outflow prevention state
The dedicated pump is stopped and the booster pump is operating
Then, the pressure of the brake cylinder can be increased.
The pump that can be depressurized is a pump that can be used for both pressure increase and pressure reduction.
Pump has a larger maximum discharge pressure than both the pressure increasing and reducing pumps
Outflow prevention valve is connected to
The pump for pressure increase / decrease
Can increase or decrease the brake cylinder hydraulic pressure.
Or you can. If you are in the outflow prevention state,
Stop the booster / reducer pump and stop pumping.
, The brake cylinder fluid pressure is increased / decreased.
The size can be made larger than in the case of the pressure pump. (8) The pump device contacts the reservoir containing the hydraulic fluid.
Connected to the reservoir and the brake series
Is provided in the middle of the liquid passage connecting the
Supply hydraulic fluid to the brake cylinder,
Pump to increase and decrease the pressure of hydraulic fluid
And a pressure-increasing / reducing pump for the liquid passage and the reservoir.
Between the pressure increase and pressure reduction pumps.
A supplement for containing the hydraulic fluid discharged from the rake cylinder
An auxiliary reservoir, the auxiliary reservoir in the liquid passage, and the reservoir;
Between the pressure booster and the pressure reducing pump.
Blocks the flow of hydraulic fluid to the reservoir, but prevents the reverse flow
Any of paragraphs (1) to (5), including the permissible check valve
A hydraulic brake device according to one of the preceding claims. In this embodiment,
The liquid passage connecting the reservoir and brake cylinder
From the flow side, check valve, auxiliary reservoir, booster / reducer pump
Pumps will be provided in series. Auxiliary reservoir and reservoir
A check valve is provided between the
Hydraulic fluid discharged from the key cylinder is not a reservoir but an auxiliary
Housed in a reservoir. Auxiliary reservoir can hold hydraulic fluid
While the pump is operating,
It is possible to decompress the cylinder. Auxiliary
In addition to the pump, the pump
Use leaked hydraulic fluid or pumps for both increasing and decreasing pressure as motors
Hydraulic fluid flowing out of the brake cylinder while operating is also collected.
Is accepted. And when the auxiliary reservoir is full,
The flow of these undesirable hydraulic fluids stops. Desiring
The upper limit of the outflow of undesired hydraulic fluid depends on the capacity of the auxiliary reservoir.
It is regulated. The capacity of the auxiliary reservoir is reduced
From the purpose of containing the hydraulic fluid discharged with control
The larger the size, the better
Smaller is better for the purpose of controlling
Therefore, it is decided in consideration of both. At that time,
The auxiliary reservoir stores hydraulic fluid under pressure.
Need to supply hydraulic fluid to the brake cylinder
The hydraulic fluid in the auxiliary reservoir is
More preferentially supplied by the intensifier / decompressor pump
For this reason, the auxiliary reservoir is
It has a capacity to accommodate the hydraulic fluid associated with decompression control.
There is no need to provide it, for example,
With a capacity to accommodate the hydraulic fluid discharged
That would be good. In addition, necessary for one pressure increase control
The capacity may be set to accommodate the working fluid. (9) The brake fluid pressure control device stores a hydraulic fluid.
A reservoir, and the reservoir and the brake cylinder
A hydraulic fluid return passage connected without passing through the pump device,
Provided in the middle of the hydraulic fluid return passage,
If the hydraulic fluid returns to the
When the current is not supplied, the hydraulic fluid return passage
(1) Including a normally open solenoid control valve
The hydraulic brake device according to any one of paragraphs (8) to (10).
(Claim 4). Between the brake cylinder and the reservoir,
When a normally open solenoid control valve is provided and current is supplied,
The hydraulic fluid return passage is shut off and the brake cylinder
Server. Reservoir of hydraulic fluid for brake cylinder
Outflow to the server. No current is supplied
In this case, the hydraulic fluid return passage is
A cylinder is communicated with the reservoir. Brake cylinder
Hydraulic fluid is allowed to flow into the reservoir,
You. This electromagnetic control valve is a so-called pressure reducing valve. Pressure reducing valve
Is usually a normally closed solenoid control valve, but
In hydraulic brake systems, normally open electromagnetic control valves are used.
Because This pressure reducing valve is supplied with current during braking.
Is kept off by braking, but the current is
Is not supplied and the communication state is maintained. At the end of braking the current
If it is no longer supplied, the work supplied to the brake cylinder
The fluid is returned to the reservoir via the electromagnetic control valve. in addition
On the other hand, if the pressure reducing valve is a normally closed electromagnetic control valve,
All the hydraulic fluid from the brake cylinder
Until the spill completion time, which can be assumed to have been
After current is supplied and maintained in communication,
And is switched to the cutoff state. Therefore,
Activates the brake cylinder after the flow is stopped
Liquid may remain and drag may occur.
You. In contrast, if the pressure reducing valve is a normally open electromagnetic control valve,
If current stops being supplied at the end of braking, communication is maintained
Hydraulic fluid from the brake cylinder
And dragging can be prevented. (10) The normally open electromagnetic control valve includes a valve seat and the valve seat.
A valve provided so that it can approach and separate
A spring biasing in a direction away from the valve seat;
An electromagnetic drive force acting in the opposite direction to the spring
The hydraulic brake according to item (9),
Key device. According to the features of this paragraph, the electromagnetic drive device of the electromagnetic control valve
Is relatively small. In the electromagnetic control valve device of this section
Means that the spring bias force separates the valve from the valve seat.
The hydraulic pressure between the brake cylinder and the reservoir
Difference according to the difference (strictly speaking, the hydraulic pressure difference before and after the pressure reducing valve)
The pressure action acts in the same direction as the biasing force of the spring.
Therefore, when no current is supplied (the electromagnetic driving force is zero)
To maintain the communication state with the valve element separated from the valve seat
In addition, the biasing force of the spring may be small. In addition, electromagnetic drive
The maximum driving force is required for the drive unit only before the solenoid valve.
After the valve is seated on the valve seat with the maximum hydraulic pressure difference
In this case, and compared to the electromagnetic driving force in that case,
Since the biasing force of the ring is negligible,
If the force is slightly larger than the hydraulic pressure based on the maximum hydraulic pressure difference
Good. On the other hand, the pressure reducing valve is a valve seat and the valve seat
And a valve provided to be able to approach and separate
A spring for biasing the child in the direction of seating on the valve seat,
An electromagnetic driving force in a direction opposite to the urging force of the spring is applied.
Normally closed electromagnetic control valve including
Is the differential pressure acting force corresponding to the hydraulic pressure difference before and after the pressure reducing valve.
Acts in the opposite direction to the urging force of the ring. Therefore, the current
To keep it shut off when not supplied, use a spring
Must be increased. In addition, electromagnetic drive
The maximum electromagnetic drive force required for the drive is that the differential pressure is zero.
In the case of, the valve is separated from the valve seat and switched to the communicating state.
The electromagnetic driving force in that case is
It must be greater than the biasing force. In other words, Spring
Must be greater than the maximum differential pressure acting force
And the electromagnetic driving force is larger than the biasing force of the spring.
Required for the normally open solenoid control valve described above.
The maximum electromagnetic drive force is simply greater than the maximum differential pressure
The maximum electromagnetic driving force is larger than in
It is necessary to design well. Also, normally open power
For magnetic control valves, the spring bias is very small.
To control the electromagnetic drive force.
When the effect of the ring bias is applied to a normally closed solenoid
It becomes smaller than the case. As a result, the spring bias
Control variation due to variation can be reduced
And control accuracy can be improved. (11) The hydraulic brake device is used as a brake operating member.
Includes master cylinder that generates hydraulic pressure according to operating force
And the pump device is connected to the master cylinder.
Not connected to a power pressure operated brake cylinder
And the normally-open electromagnetic control valve is
The hydraulic fluid return connecting the storage cylinder and the reservoir
(9) or (10)
The hydraulic brake device according to claim (claim 5). Described in this section
Hydraulic brake system is connected to the pump system.
Power-operated brake not connected to master cylinder
The pressure reducing valve for the cylinder is a normally open electromagnetic control valve.
Master pressure-operated brake series connected to the master cylinder
After braking is finished, the
Hydraulic fluid return passage
The hydraulic fluid to the master cylinder without fail
If there is, it can be returned to the reservoir. That
Normally open the pressure reducing valve for the power pressure operated brake cylinder
If the solenoid control valve is
Can be prevented. Master pressure operated brake series
Is connected to the master cylinder and connected to the pump device
Master cylinder and pump device
May be connected to both. The former
In case, the master pressure operated brake cylinder is an electromagnetic control valve
Directly to the master cylinder and reservoir without going through
Since the connection can be established, control of the electromagnetic control valve
Can be returned to the reservoir without interruption. Places that are the latter
At least the master pressure-operated brake cylinder
The master pressure operated brake cylinder is
To the master cylinder, or
A master communication solenoid control valve that shuts off
However, this master communication solenoid control valve is
Normally open solenoid control valve for
You. Therefore, at the end of braking, the master
By stopping the current supply to the
Key cylinder to the master cylinder and reservoir
To ensure that the hydraulic fluid is
Can be drained from Linda. In other words,
Master pressure cylinder and reservoir
Provided in the middle of the hydraulic fluid return passage connected without passing through
The pressure reducing valve does not need to be a normally open electromagnetic control valve,
A normally closed electromagnetic control valve may be used. Normally closed solenoid control valve
By not supplying it, it can be kept in a cutoff state.
Therefore, pressure reduction for the power pressure operated brake cylinder
The valve is a normally open electromagnetic control valve, and the master pressure operated brake
If the pressure reducing valve for the cylinder is a normally closed solenoid control valve,
Power consumption can be reduced while preventing shearing.
You. (12) The hydraulic brake device is provided as the master cylinder.
Pressure-operated brake cylinder connected to the
The star pressure operated brake cylinder and the reservoir
Hydraulic fluid return connected without passing through pump device or master cylinder
Flow passage and the hydraulic fluid return passage.
When the hydraulic fluid is supplied to the hydraulic fluid return passage.
To return the hydraulic fluid when no current is supplied.
Normally closed electromagnetic control valve that is in a shut-off state to shut off the road
The hydraulic brake device according to (11). Master pressure operated brake
Replace the pressure reducing valve for the key cylinder with a normally closed solenoid control valve
For example, if the electrical system fails, activate the brake.
Can be. The master pressure operated brake cylinder is
Connected to the master cylinder and connected to the pump
And the master cylinder and pump unit
Some may be connected. And in the latter case
Is disconnected from the master cylinder when the electrical system is normal.
It is connected to the pump device and is shut off from the pump device in the event of an abnormality.
So that it can be disconnected and communicated with the master cylinder.
Can be. Therefore, in either case,
When the pressure reducing valve is a normally closed electromagnetic control valve,
By maintaining the shut-off state, the operation of the master cylinder
To supply hydraulic fluid to the master pressure operated brake cylinder
The brake can be operated more. Ma
In addition, the master pressure operated brake cylinder and the aforementioned power pressure operated
Normally open the pressure reducing valve for both the brake cylinder and the electromagnetic
Control valve supplies current to all pressure reducing valves during braking
To the master pressure operated brake cylinder.
If the pressure reducing valve is a normally closed solenoid control valve,
Need not be supplied. Therefore, all pressure reducing valves
Power consumption is lower than when a normally closed solenoid
Can be made. (13) The brake fluid pressure control device controls the brake system.
Provided between the cylinder, the pump device, and the reservoir,
Connect the brake cylinder to the pump device or
Includes hydraulic pressure control valve device that communicates with valve
(12) The hydraulic brake device according to any one of (12). Book
According to embodiments, in cooperation with the control of the pump device, or
Separately from control of the pump device, control of the hydraulic pressure control valve device
It is possible to control the hydraulic pressure of the brake cylinder more
You. For example, multiple brakes are usually controlled by controlling the pump device.
Control the hydraulic pressure of the
Anti-lock control, traction control,
-If vehicle stability control is required,
When the hydraulic pressure of the brake cylinder is
Hydraulic fluid pressure (controlled by pump device control
May or may not need to be controlled individually
It becomes possible. (14) A pump device including one or more pumps and the pump device
Brake cylinder connected to the pump device and hydraulic fluid
Reservoir, and the reservoir and the brake syringe
And hydraulic fluid return without passing through the pump device
A passage, and a hydraulic fluid return passage,
Shuts off the hydraulic fluid return passage when energy is supplied
When the electrical energy is not supplied
A normally open power supply that is in communication with the hydraulic fluid return passage
Magnetic shut-off valve and, if supplied with electrical energy,
The difference between the hydraulic pressure before and after itself is calculated by the amount of supplied electric energy.
Control state to control the size according to the
Communicates the return path for hydraulic fluid when no gear is supplied
Either one of the normally open electromagnetic hydraulic pressure control valves to be in communication
And a hydraulic brake device including. Pump device described in this section
As described in paragraphs (1) to (8), both
Including decompression pumps such as pumps for pumping and pumps for decompression
But limited to those that include a decompression pump
Not include one or more pumps dedicated to boosting pressure.
It can also include an accumulator. 2
If more than one booster pump is included,
Pump and high pressure booster pump
Is desirable. Even if the pump device does not include
If the hydraulic fluid in the brake cylinder is
Return to reservoir via solenoid on-off valve or solenoid control valve
As a result, the pressure is reduced. Solenoid on-off valve
Is switched to the communication state during pressure reduction control.
State is not always maintained, and alternates between the communication state and the cutoff state.
In some cases. Electromagnetic fluid pressure control valve
Since it is provided between the
If the pressure difference before and after itself is small,
The rake cylinder hydraulic pressure is reduced. In any case,
The brake system is controlled by the solenoid on-off valve and the electromagnetic hydraulic pressure control valve.
The hydraulic pressure of the Linda is controlled to be reduced, and after the braking ends
Is in a communication state when the electric energy amount is set to 0
, So that dragging can be prevented well.
You. Note that the hydraulic brake system described in this section does not comply with (10).
Chair (13) may apply. For example, electromagnetic switching
Valves and solenoid valves are seating valves described in (10).
As described in section (11), the master serial
Power brake cylinder not connected to the
It is desirable to apply to a pressure reducing valve provided correspondingly.

[0004]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a hydraulic brake system according to a first embodiment of the present invention; In FIG. 1, 10
Is a brake pedal as a brake operating member, and 1
2 is a master cylinder. The master cylinder 12 is of a tandem type having two pressurizing chambers. One of the pressurizing chambers is connected to a wheel cylinder 18 of the left front wheel 16 via a liquid passage 14, and the other pressurizing chamber is connected to the other pressurizing chamber. The wheel cylinder 24 of the right front wheel 22 is connected via the liquid passage 20. In the present embodiment, one wheel cylinder is connected to one pressurizing chamber. In the middle of the liquid passages 14 and 20, master shutoff valves 26 and 2 are provided, respectively.
8 are provided. The master shutoff valves 26 and 28 can be switched between a shutoff state in which the wheel cylinder is shut off from the master cylinder 12 and a communication state in which the wheel cylinder communicates with the master cylinder 12 by turning on and off the solenoid. It is a normally-open valve that is kept in a cut-off state by supplying a current during braking, and is kept in a communicating state by not supplying current during non-braking, and is kept in a communicating state when an electric system is abnormal.

A master reservoir 30 for supplying hydraulic fluid to the master cylinder 12 and the wheel cylinders 18 and 24 described above
And wheel cylinders 36, 3 of the left and right rear wheels 32, 34
8, a pump device 40 is provided. The pump device 40 includes two pumps 42 and 44, a check valve 45
a, b, the outflow prevention valve 46, and the like. The hydraulic fluid in the master reservoir 30 is pressurized by one of the pumps 42 and 44 and is supplied to each of the wheel cylinders 18, 24, 3.
6, 38. Also, the wheel cylinder 18,
The hydraulic fluids 24, 36, 38 are discharged through the pump 44 and flow into the master reservoir 30. The hydraulic pressure of each of the wheel cylinders 18, 24, 36, 38 is controlled such that a deceleration corresponding to the operation force of the brake pedal 10 is obtained. In the present embodiment, the braking effect control is performed.

[0006] The two pumps 42 and 44 are arranged in parallel with each other as shown in FIG.
8, 24, 36, 38. One pump 42 is a high-pressure small-capacity plunger pump (hereinafter, referred to as a high-pressure small-capacity plunger pump having a large maximum discharge pressure and a small maximum discharge amount per unit time.
Pump 42) and the other pump 44
Is a low-pressure large-capacity gear pump having a small maximum discharge pressure and a large maximum discharge amount (hereinafter, referred to as a low-pressure pump 44).
It is. The high-pressure pump 42 is operated by driving a high-pressure motor 48, and the low-pressure pump 44 is operated by driving a low-pressure motor 50. By controlling the rotation speeds of the high-pressure motor 48 and the low-pressure motor 50, the discharge amount per unit time can be controlled within a range not exceeding the maximum discharge pressure. The low-pressure motor 50 is rotatable in both forward and reverse directions, and can rotate the low-pressure pump 44 in both forward and reverse directions. By switching the rotation direction of the low pressure pump 44,
It is possible to switch between the increased pressure state and the reduced pressure state.

When the low-pressure motor 50 is rotated in one direction, the low-pressure pump 44 is in a pressure-increasing state in which the hydraulic fluid is sucked from the master reservoir and discharged to the wheel cylinder. When rotated in the other direction, the low-pressure pump 44 is in a reduced pressure state in which the hydraulic fluid is sucked from the wheel cylinder side and flows out to the master reservoir side. By controlling the rotation direction of the low-pressure motor 50 in this manner, the low-pressure pump 44
The pressure can be switched between a pressure increasing state in which the hydraulic fluid is supplied to the wheel cylinders, and a pressure reducing state in which the hydraulic fluid is discharged from the wheel cylinders. As described above, since the low-pressure pump 44 is a gear pump, leakage may occur. However, the pressure can be reduced by utilizing the leakage.

Here, the low-pressure pump 44 is activated during normal braking, that is, when the wheel cylinder fluid pressure is about 3 MPa or less, and is stopped when it exceeds 3 MPa. On the other hand, the high pressure pump 42
The stop state is maintained when the pressure is less than about 3 MPa, and the operation state is set when the pressure exceeds 3 MPa. Thus, the hydraulic fluid discharged from either the low-pressure pump 44 or the high-pressure pump 42 is selectively supplied to the wheel cylinders 18, 24, 36, 38. During normal braking, the operation state of the low-pressure pump 44 is controlled by controlling the operation state of the low-pressure motor 50, and the hydraulic pressure of the wheel cylinders 18, 24, 36, and 38 is controlled.
In the present embodiment, since four wheel cylinders 18, 24, 36, 38 are connected to one pump device 40, the hydraulic fluid controlled by the pump device 40 is supplied to the wheel cylinders 18, 24, 36, 38. Also supplied, these hydraulic pressures can be controlled to approximately the same magnitude. Further, since the low-pressure pump 44 has a large capacity, it can supply the hydraulic fluid at a large flow rate at the initial stage of depression of the brake pedal 10 and the like, and can reduce a delay in braking effect. Further, during the normal braking, a braking effect control for increasing and decreasing the wheel cylinder hydraulic pressure is performed so that a deceleration corresponding to the depression force of the brake pedal 10 is obtained.

The pedaling force is large and the wheel cylinder hydraulic pressure is 3
When the pressure exceeds MPa, the high-pressure pump 42 is operated and the operation of the low-pressure pump 44 is stopped. By supplying the hydraulic fluid discharged from the high-pressure pump 42 to the wheel cylinders 18, 24, 36, 38, the pressure is further increased, and a large braking force can be obtained. When the wheel cylinder hydraulic pressure exceeds 3 MPa, such as during emergency braking, the brake feeling hardly causes a problem. Therefore, it is not necessary to reduce the wheel cylinder hydraulic pressure, and it is sufficient to increase the wheel cylinder hydraulic pressure. , High pressure pump 4
It is not necessary to make 2 switchable to a reduced pressure state.

The outflow prevention valve 46 is, as shown in FIG.
This is a pilot-type control valve that can be switched between a communicating state and an outflow preventing state. When the discharge pressure of the high-pressure pump 42 reaches a set pressure (for example, 3 MPa), the state is switched from the communicating state to the outflow preventing state. The flow of the working fluid toward the low pressure pump 44 is blocked. This prevents the hydraulic fluid in the wheel cylinders 18, 24, 36, and 38 from leaking from the low-pressure pump 44 and flowing out to the master reservoir side. If the outflow prevention valve 46 is switched to the outflow prevention state, it is also possible to avoid leakage from the low pressure pump 44 when the low pressure pump 44 fails. In the present embodiment, a reverse drive preventing device is provided between the low-pressure pump 44 and the low-pressure motor 50. For this reason, a hydraulic pressure difference occurs before and after the low-pressure pump 44 due to the leakage of the hydraulic fluid in the outflow prevention valve 46, and the reverse drive torque for operating the low-pressure pump 44 as a motor based on the hydraulic pressure difference is reduced. Even if it does, the rotation of the motor is reliably avoided. It should be noted that the reverse drive blocking device is not indispensable, and the outflow of the working fluid can be sufficiently prevented without the reverse drive blocking device.

Each wheel cylinder 18, 24, 36, 3
In the middle of the pump passage 52 connecting the pump 8 and the pump device 40, there is provided an electromagnetic on-off valve 54 as a pressure-intensifying valve that can be switched between a communicating state for communicating them and a shut-off state for shutting them off. The electromagnetic on-off valve 54 is a normally closed electromagnetic on-off valve that is in a cutoff state when no current is supplied, but is in a communicating state when a current is supplied. Pump device 40
Is turned on, the pressure-intensifying valve 54 is switched to the communicating state, and the wheel cylinders 18,
The inflow of the hydraulic fluid to 24, 36, 38 is permitted. If the pressure increasing valve 54 is kept in the communicating state, the hydraulic fluid controlled in the pump device 40 is similarly supplied to each wheel cylinder, so that these wheel cylinder hydraulic pressures can be made the same.

The wheel cylinders 18 of the front wheels 16, 22
24, a hydraulic fluid return passage 5 that connects the wheel cylinders 36, 38 of the rear wheels 32, 34 and the master reservoir 30 by bypassing the pump device 40 and the master cylinder 12.
In the middle of the hydraulic fluid return passage 58, pressure reducing valves 60 and 62 are provided which can be switched between a communication state for communicating the hydraulic fluid return passage 58 and a cutoff state for shutting off. Wheel cylinders 18, 2 for front wheels 16, 22
The pressure reducing valve 60 provided corresponding to 4 is a normally-closed electromagnetic opening / closing valve which is in a shut-off state when current is not supplied, and is provided corresponding to the wheel cylinders 36, 38 of the rear wheels 32, 34. The pressure reducing valve 62 is a normally-open electromagnetic on-off valve that is in a communication state when no current is supplied. Front wheels 16, 22
Of the master cylinder 1
2 and the pump device 40 are both connected. The pump device 40 is connected to the wheel cylinders 36 and 38 of the rear wheels 32 and 34, but the master cylinder 12 is not connected. In other words, the pressure reducing valve 60 for the master pressure-operated wheel cylinders 18 and 24 connected to both the master cylinder 12 and the pump device 40 is a normally closed solenoid on-off valve. The pressure reducing valve 62 for the power pressure operated wheel cylinders 36 and 38 connected to 40 is a normally open electromagnetic on / off valve.

When the pressure-reducing valve for the power-pressure operated wheel cylinder is a normally-closed electromagnetic on-off valve, the time from the end of braking to the time when the hydraulic fluid in the wheel cylinder is completely discharged to the master reservoir can be estimated. , Is kept in a communication state by supplying a current, and then returned to a cutoff state. However, the hydraulic fluid may remain in the wheel cylinder, which may cause dragging. On the other hand, if the pressure reducing valve is a normally-open electromagnetic on-off valve, it can be kept in communication by stopping the supply of current after braking, so that all hydraulic fluid in the wheel cylinder can be maintained in the master reservoir. , And dragging can be prevented. On the other hand,
The master pressure operated wheel cylinder is normally made to communicate with the master cylinder during non-braking for fail-safe and the like. In the present embodiment, the master shut-off valves 26 and 28 are kept in communication during non-braking (when braking is completed). Therefore, at the end of braking, the hydraulic fluid in the master pressure-operated wheel cylinders 18 and 24 is released from the pressure reducing valve 6.
Instead of returning to 0, the pressure is returned to the master cylinder 12 through the master shut-off valves 26 and 28 in the communicating state.
Even if 0 is not a normally open electromagnetic on-off valve, dragging can be prevented.

As described above, the master shut-off valves 26, 28 are returned to the communication state when the electric system is abnormal (current is not supplied). Further, the pressure increasing valve 54 is returned to the holding state. Therefore, the master pressure operated wheel cylinders 18, 2
4 is the master cylinder 1
2 will be communicated. The hydraulic fluid of the master cylinder 12 is supplied to the master pressure operating wheel cylinders 18 and 24, and the brake is operated by the master pressure.
In this case, if the pressure reducing valve is a normally-open electromagnetic on-off valve, it cannot be switched to the shut-off state, and the brake may not operate. On the other hand, in the present embodiment, since the pressure reducing valve 60 is a normally-closed electromagnetic on-off valve, the brake can be operated even when the electric system is abnormal. As described above, in the present embodiment, the pressure reducing valve 60 corresponding to the master pressure operating wheel cylinders 18 and 24 is a normally closed electromagnetic on / off valve, and the pressure reducing valve 62 corresponding to the power pressure operating wheel cylinders 36 and 38 is normally open. By using the electromagnetic opening / closing valve described above, it becomes possible to operate the brake satisfactorily in the event of an abnormality in the electric system while preventing dragging. Further, power consumption during braking can be reduced as compared with a case where the pressure reducing valves for all the wheel cylinders are normally opened electromagnetic on / off valves.

The present hydraulic brake device is provided with a brake hydraulic pressure control device 70 mainly composed of a computer. The input part of the brake fluid pressure control device 70 includes a brake switch 72 for detecting that the brake pedal 10 is depressed, a master pressure detection device 74 for detecting the fluid pressure in the pressurizing chamber of the master cylinder 12, and a pump. A pump pressure detecting device 76 for detecting the hydraulic pressure on the discharge side of the device 40, a wheel cylinder pressure detecting device 78 for detecting the hydraulic pressure of each wheel cylinder, a wheel speed sensor 80 for detecting the rotational speed of each wheel, and the like are connected. The output unit is connected to the solenoid of each of the above-mentioned solenoid on-off valves via a drive circuit (not shown), and the low-voltage motor 50 and the high-pressure motor 48 are connected via the drive circuit. The ROM stores various programs such as a pump rotation state control program, an antilock control program, a traction control program, and the like, shown in the flowchart of FIG. 2, and a motor rotation speed control table shown in a graph of FIG. However, in the present embodiment, the operating states of the low-pressure motor 50 and the high-pressure motor 48 are controlled so that the deceleration according to the depression force of the brake pedal 10 is obtained, and the low-pressure pump 44,
The rotation state of the high-pressure pump 42 is controlled.

The depression force of the brake pedal 10 is obtained based on the detection result of the master pressure detection device 74. The master cylinder 12 is provided with a stroke simulator 82 so that the driver does not feel uncomfortable even when the master shutoff valves 26 and 28 are shut off. Each booster valve 5
4 is in the communicating state and the pressure reducing valves 60 and 62 are in the shutoff state, the hydraulic pressure on the discharge side of the pump device 40 detected by the pump pressure detecting device 76 is the same as the hydraulic pressure of each wheel cylinder. It can be estimated that there is. Also,
The braking slip state and the driving slip state of each wheel 16, 22, 32, and 34 are acquired based on the wheel speed detected by the wheel speed sensor 80, the estimated vehicle speed acquired based on the wheel speed, and the like. Antilock control and traction control are performed based on these slip states.

The operation of the hydraulic brake device configured as described above will be described. When the electric system is normal, the hydraulic pressure of the wheel cylinders 18, 24, 36, 38 is controlled in accordance with the execution of the pump rotation state control program shown in the flowchart of FIG. Step 1
In (hereinafter, abbreviated as S1; the same applies to other steps), it is determined whether or not the brake pedal 10 is depressed based on the state of the brake switch 72. When it is depressed, in S2, the master shut-off valves 26 and 28 are turned off and the pressure increasing valve 54 is turned on.
Are switched to the communicating state, and the pressure reducing valve 62 is switched to the shut-off state. In S3, a target wheel cylinder hydraulic pressure P ^* _WC is obtained based on the depression force of the brake pedal 10. The magnitude of the wheel cylinder hydraulic pressure is determined so that deceleration according to the pedaling force is obtained. In S4, it is determined whether the target wheel cylinder hydraulic pressure P ^* _WC is 3 MPa or less. That is, during normal braking,
The determination is YES, and in S5, the low-voltage motor 50
Is controlled. By controlling the rotation direction of the low-pressure motor 50, the wheel cylinders 18, 24, 36, 3
Hydraulic fluid is supplied to and discharged from the hydraulic fluid 8. In addition, by controlling the rotation speed, the amount of hydraulic fluid in these cases is controlled. Here, the high-pressure motor 48 is kept stopped. When the target wheel cylinder hydraulic pressure P ^* _WC exceeds 3 MPa, that is, at the time of emergency braking with a large pedal effort, the operation state of the high-pressure motor 48 is controlled,
The low voltage motor 50 is kept stopped. When the high-pressure hydraulic fluid is supplied to the wheel cylinder, the hydraulic pressure is increased. In this case, the outflow prevention valve 46 is switched to the shut-off state, and the leakage of the working fluid from the low-pressure pump 44 is avoided.

In step S5, the control of the low-voltage motor 50 is performed.
Control is performed according to the table shown in the graph of FIG.
You. Target wheel cylinder fluid pressure P^* _WCIs a real wheel series
Hydraulic pressure P_WCIf it is larger, the pressure is increased and
The pressure motor 50 is rotated in the forward direction. Goal wheel
Cylinder pressure P^* _WCIs the actual wheel cylinder pressure P_WCYo
If it is smaller, the pressure is reduced and the low-pressure motor 50
Are rotated in the opposite direction. The rotation speed is
Eel cylinder hydraulic pressure P^* _WCAnd actual wheel cylinder pressure P
_WCWhen the difference from the difference is large, the difference is made larger than when the difference is small.
The discharge or discharge volume is increased and the target wheel
Cylinder pressure P^* _WCApproached. As shown in the figure
And the target wheel cylinder fluid pressure P^* _WCAnd real wheel series
Hydraulic pressure P _WCIs formed by the two-dot chain line in FIG.
Is determined, and it is decided about that area.
Rotation speed R '_n, R_nAnd the low-pressure motor 50 increases pressure
It can be rotated in the direction or the decompression direction.

As shown in the figure, when the difference between the target wheel cylinder fluid pressure P ^* _WC and the actual wheel cylinder fluid pressure _PWC is small, the holding state is set, and the rotation of the low-pressure motor 50 is stopped. Can be In the present embodiment, hysteresis is provided, and the target wheel cylinder hydraulic pressure P ^*
The difference between _WC and the actual wheel cylinder fluid pressure P _WC increases,
If the difference shown by the dashed line is exceeded, the low-voltage motor 50 is rotated. However, if these differences are reduced, and if the broken line is exceeded, the rotation of the low-voltage motor 50 is stopped. By providing the hysteresis, it is possible to prevent the control of the rotation state of the low-voltage motor 50 from being frequently changed. On the other hand, if the brake pedal 10 is not depressed, the determination in S1 is NO, and the low-voltage motor 5
Both 0 and the high-pressure motor 48 are kept stopped. As a result, wasteful consumption of electric energy can be avoided.

When the electric system is abnormal, the master shutoff valves 26 and 28 are kept in communication with each other, so that the master cylinder 12 is connected to the wheel cylinders 18 and 24. When the brake pedal 10 is depressed, the hydraulic fluid of the master cylinder 12 is supplied to the wheel cylinders 18 and 24 to operate the brake. The working fluid is supplied to the wheel cylinders 18 and 24 on the front wheel side because the capacity of the wheel cylinder is larger on the front wheel side than on the rear wheel side.

When at least one of the braking slip states of the wheels becomes excessive with respect to the road surface friction coefficient, antilock control is performed. With the master shut-off valves 26 and 28 kept in the shut-off state, the hydraulic fluid supplied from the pump device 40 controls each of the wheel cylinders 18, 24, 36 and 38 by controlling the pressure-increasing valves 54 and the pressure-reducing valves 60 and 62. The hydraulic pressure is
Control is performed so that the braking slip state of each wheel 16, 22, 32, 34 is maintained in an appropriate state. Further, when the driving slip state of the driving wheels becomes excessive, traction control is performed. In the present embodiment, since the rear wheels are the drive wheels, the master shutoff valves 26 and 28 are kept in the communicating state, and the pressure increasing valves 54 provided for the front wheels 16 and 22 are kept in the shutoff state. The hydraulic pressure of the wheel cylinders 36, 38 of the rear wheels 32, 34 is controlled by controlling the pressure increasing valve 54 and the pressure reducing valve 62. If the brake pedal 10 is depressed during traction control, the master cylinder 1
2 is connected to the master shut-off valves 26 and 28 in the communication state.
, And can be supplied to the wheel cylinders 18 and 24. During the antilock control and the traction control, it is not essential to control the pump device 40.
A predetermined rotation state can be maintained.

As described above, in the present embodiment, the hydraulic pressure of the wheel cylinder is controlled by controlling the pump device 40. Further, since all four wheel cylinders 18, 24, 36, 38 are connected to the pump device 40, the hydraulic pressures of the four wheel cylinders 18, 24, 36, 38 can be controlled to the same magnitude. Becomes When the hydraulic fluid discharged from the pump is controlled by a hydraulic pressure control valve provided corresponding to each wheel cylinder to control the wheel cylinder hydraulic pressure, a control variation occurs. Since common control is possible, the hydraulic pressure of each wheel cylinder can be controlled to the same magnitude. Further, since two pumps of a high-pressure small-capacity type and a low-pressure large-capacity type are provided, the size can be reduced and the cost can be reduced as compared with a single high-pressure large-capacity pump. In addition, since the low-pressure large-capacity pump is a gear pump that can rotate in both forward and reverse directions, braking effect control can be performed so that deceleration according to the pedaling force can be obtained during normal braking when the pedaling force is not so large. Becomes When the pedaling force is very large, there is almost no need to reduce the wheel cylinder hydraulic pressure, and it is sufficient to supply a high pressure and a small amount of hydraulic fluid. Further, wheel cylinders 18 connected to the master cylinder 12,
24 is a normally closed solenoid on-off valve, and wheel cylinders 36, 3 not connected to master cylinder 12.
By setting the pressure reducing valve corresponding to 8 to a normally-open solenoid on-off valve, the brake can be operated when the electric system is abnormal, and dragging can be prevented.

In this embodiment, a pump device control device is constituted by a portion for executing a pump rotation state control program of the brake fluid pressure control device 70, and the brake fluid pressure control is performed by the pump device control device and the pump device 40. The device will be configured.

The structure of the pump device is not limited to that of the above embodiment, and the structure of the pump device 88 shown in FIG.
It can also be. On the upstream side of the low pressure pump 44,
A check valve 90 and an auxiliary reservoir 92 are provided in series, and a pump device 88 is configured by the two pumps 42 and 44, the check valve 90, the auxiliary reservoir 92, and the like. The check valve 90 allows the flow of the hydraulic fluid from the master reservoir 30 to the low-pressure pump 44, but prevents the flow in the reverse direction. The auxiliary reservoir 92 is not large in volume but large enough to store the hydraulic fluid flowing out of the wheel cylinders 18, 24, 36, 38 during a plurality of pressure reductions.

The hydraulic fluid discharged from the wheel cylinder via the low pressure pump 44 during the pressure reduction, the high pressure pump 42
The hydraulic fluid leaked from the discharge side during the operation of the auxiliary reservoir 92
Is stored in A check valve 90 is provided upstream of the auxiliary reservoir 92.
Is provided, the hydraulic fluid discharged via the low-pressure pump 44 is stored in the auxiliary reservoir 92. When the auxiliary reservoir 92 is in the full state, the hydraulic pressure difference before and after the low-pressure pump 44 is reduced, and leakage of hydraulic fluid from the wheel cylinder side to the master reservoir side can be reduced. As described above, since the auxiliary reservoir 92 has both the function of accommodating the hydraulic fluid discharged at the time of depressurization and the function of reducing the leakage in the low-pressure pump 44, the capacity is determined in consideration of these. It is decided. When the hydraulic fluid is pressurized by the low-pressure pump 44, the hydraulic fluid contained in the auxiliary reservoir 92 is sucked, or the hydraulic fluid in the master reservoir 30 is sucked through the check valve 90. Further, in the present embodiment, since the reverse drive preventing device is provided between the low-pressure pump 44 and the low-pressure motor 50, the pump pressure increases when the high-pressure pump 42 operates, and If hydraulic fluid leaks from the low pressure pump 44, it will cause the motor to reverse and prevent large amounts of hydraulic fluid from flowing out through the low pressure pump 44.

The capacity of the auxiliary reservoir 92 is not limited to the capacity in the above-described embodiment, but may be an amount corresponding to the amount of hydraulic fluid discharged at one pressure increase. Further, the reverse drive preventing device is not indispensable. Even if the low-pressure motor 50 is rotated in the pressure-reducing direction and a large amount of hydraulic fluid flows out, if the auxiliary reservoir 92 is in a full state, no more hydraulic fluid will flow out.

The manner of controlling the operating states of the two pumps 42 and 44 is not limited to the case of the above-described embodiment.
Other embodiments are also possible. For example, at the beginning of braking,
Both the low-pressure pump 44 and the high-pressure pump 42 can be activated. In this case, the flow rate of the hydraulic fluid that can be supplied to the wheel cylinders is reduced when only the low-pressure pump 44 is activated. The brakes can be made larger and the brakes can be operated quickly.

Further, the high-pressure pump 42 may be switchable between an increased pressure state and a reduced pressure state. In this case, it is possible to accurately control the wheel cylinder hydraulic pressure even at a high pressure. The pump device 94 has the structure shown in FIG. Two directional control valves 96 and 98 are provided on the discharge side of the high-pressure pump 42. The direction switching valve 96 can switch between a first state in which the discharge port of the high-pressure pump 42 is connected to the wheel cylinder and a second state in which the discharge port is connected to the master reservoir 30 via the liquid passage 100. The direction switching valve 98 is connected to the high-pressure pump 42.
Can be switched between a first position where the discharge port is connected to the wheel cylinder and a second position where the wheel cylinder is connected to the suction port via the liquid passage 102. When both the direction switching valves 96 and 98 are at the first position, the pressure is increased. The high pressure pump 42 allows the master reservoir 30
The hydraulic fluid sucked from is supplied to the wheel cylinder. When both of the direction switching valves 96 and 98 are switched to the second position, the pressure is reduced. The hydraulic fluid of the wheel cylinder is returned to the master reservoir 30 via the liquid passage 102, the high-pressure pump 42, and the liquid passage 100. Further, a damper may be provided on the wheel cylinder side of the high-pressure pump 42 and the low-pressure pump 44. The pulsation of the pump can be suppressed by the damper.

Further, it is not essential that the pressure increasing valve 54 be a normally-closed electromagnetic on-off valve, but may be a normally-opened electromagnetic on-off valve. It is not always necessary to enable antilock control and traction control. In this case, the pressure increasing valve 54, the pressure reducing valves 60, 62, etc. are not required, and the hydraulic fluid of the power pressure operated wheel cylinder can be returned to the master reservoir 30 by the rotation of the low pressure pump 44 in the pressure reducing direction at the end of braking. It is. Further, in an emergency or the like, prior to the operation of the brake pedal 10, the wheel cylinders 18, 2
An automatic brake can also be operated, for example, by supplying hydraulic fluid to 4, 36, 38. Further, the pressure increasing valve 54 and the pressure reducing valve 6
Numerals 0 and 62 are not merely on-off valves but may be hydraulic control valves capable of controlling the flow rate of the hydraulic fluid flowing in the open state.

The master pressure operated wheel cylinder 1
In addition to providing a connection passage connecting the 8, 24, an electromagnetic on-off valve may be provided in the middle of the connection passage. The solenoid on-off valve has two wheel cylinders 1 for antilock control etc.
When the hydraulic pressures of the cylinders 8 and 24 are controlled to different levels, the shutoff state is set. When the hydraulic pressures of the two wheel cylinders are controlled to the same level, the master cylinder 1 is controlled when the electrical system fails.
The communication state is established when the brake is operated by the second hydraulic fluid. If the wheel cylinders 18 and 24 are communicated, the left and right wheel cylinder hydraulic pressures can be controlled to the same height, and the braking stability can be improved. Further, even when the hydraulic pressure cannot be generated in one of the two pressurizing chambers of the master cylinder 12, there is an advantage that the left and right braking forces can be the same.

Further, in the above embodiment, one pump device 40 is connected to all the four brake cylinders 18, 24, 36, 38, and the front wheels 16, 2 of them are connected.
The master cylinder 12 is attached to the second wheel cylinders 18 and 24.
Was connected, but four wheel cylinders 18, 2
4, 36, 38, master cylinder 12, pump device 4
The connection mode with 0 is not limited to the case in the above embodiment, but may be another mode. For example, the pump device 40 is connected to the wheel cylinders 36, 38 of the rear wheels 32, 34, and the master cylinder 12 is connected to the wheel cylinders 18, 24 of the front wheels 16, 22, or all the wheel cylinders 18, 24 are connected. , 36, 38, both the master cylinder 12 and the pump device can be connected. The pump device 40 may be connected to at least one of the four wheel cylinders.

The high-pressure pump 42 may be a gear pump. In this case, the pressure can be reduced by rotating the high-pressure pump in the reverse direction. Further, the pump device may not include a decompression pump. In that case, the hydraulic fluid in the wheel cylinder is discharged to the reservoir 30 via the decompression valves 60 and 62, so that the pressure is reduced. Further, when the target wheel cylinder hydraulic pressure is 3 MPa or more, both the high-pressure pump 42 and the low-pressure pump 44 can be set to the operating state. The low pressure pump 44 and the high pressure pump 4
For each of the two, a relief valve that sets the maximum discharge pressure to the valve opening pressure may be provided. Furthermore, the outflow prevention valve 4
6 is switched to the outflow prevention state when the discharge pressure of the high-pressure pump 42 reaches the set pressure, but it may be switched when the hydraulic pressure of the wheel cylinder reaches the set pressure. Even in that case, the pressure reducing pump 4
4 can be prevented. Further, the magnitude of the set pressure when switching from the communication state to the outflow prevention state is not limited to the case in the above embodiment. further,
An electromagnetic on-off valve can be used, but the outflow prevention valve is not essential. Although not specifically exemplified, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an entire hydraulic brake device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a pump rotation state control program stored in a ROM of a brake fluid pressure control device included in the hydraulic brake device.

FIG. 3 is a graph showing a control table of a pump rotational speed stored in the ROM.

FIG. 4 is a circuit diagram illustrating a pump device included in a hydraulic brake device according to another embodiment of the present invention.

FIG. 5 is a circuit diagram illustrating a pump device included in a hydraulic brake device according to yet another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 30 Master reservoir 40, 88, 94 Pump device 42 High pressure pump 44 Low pressure pump 46 Outflow prevention valve 48 High pressure motor 50 Low pressure motor 62 Pressure reducing valve 70 Brake fluid pressure control device 90 Check valve 92 Auxiliary reservoir 96, 98 Direction Switching valve

Claims (5)

[Claims] 1. A hydraulic brake device comprising: a brake cylinder for operating a brake by a hydraulic pressure of a hydraulic fluid; and a brake hydraulic pressure control device for controlling a hydraulic pressure of the brake cylinder, wherein the brake hydraulic pressure control device is provided. Comprises at least one pump connected to the brake cylinder, and a pressure increasing state for supplying the brake cylinder with hydraulic fluid discharged from at least one of the at least one pump; and the at least one pump. A pump device that can be selectively switched to a reduced pressure state in which the hydraulic fluid is discharged from the brake cylinder via at least one of the following: a fluid in the brake cylinder by controlling a rotation state of at least the at least one pump; And a pump device control device for controlling the pressure. . 2. The hydraulic brake device according to claim 1, wherein the pump device is connected to a plurality of the brake cylinders, and controls the hydraulic pressure of the plurality of brake cylinders in common. 3. The pump device includes two pumps connected in parallel with each other, wherein one of the pumps has a larger maximum discharge amount per unit time and a smaller maximum discharge pressure than the other pump, and The pump device is switched between a pressure increasing state in which the hydraulic fluid is discharged to the wheel cylinder side and a pressure reducing state in which the hydraulic fluid is sucked from the wheel cylinder side by switching the rotation direction of one of the pumps. 3. The hydraulic brake device according to 2. 4. A brake fluid pressure control device comprising: a reservoir for containing a hydraulic fluid; a hydraulic fluid return passage connecting the reservoir to the brake cylinder without passing through the pump device; A normally open electromagnetic control valve which is provided on the way and which is in a cut-off state for shutting off the hydraulic fluid return passage when current is supplied, and which is in a communication state for communicating the hydraulic fluid return passage when no current is supplied. The hydraulic brake device according to any one of claims 1 to 3, wherein: 5. The hydraulic brake device according to claim 1, further comprising a master cylinder for generating a hydraulic pressure in accordance with an operation force of a brake operating member, wherein the pump device is connected to a power-pressure operated brake cylinder that is not connected to the master cylinder. ,And,
The hydraulic brake device according to claim 4, wherein the normally-open electromagnetic control valve is provided in the middle of the hydraulic fluid return passage that connects the power hydraulic brake cylinder and the reservoir.