JPH0826086A - Brake fluid pressure control device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a brake fluid pressure control device with low required machining accuracy and low manufacturing cost. [Structure] Master cylinder 13 and wheel cylinder 18
Fluid passages 15 and 17 for connecting to the fluid passages, a switching control valve 16 provided in the fluid passages 15 and 17 for controlling brake fluid pressure, a drainage passage 21 connected to the switching control valve 16, and a drainage passage 21 The switching control valve 16 has a housing 19 and a first communication path that communicates the inside of the housing 19 with the liquid passages 15 and 17, and a valve control means 35 that controls the opening and closing of the opening and closing valve 34. Second liquid chamber 22 communicating with the liquid chamber 20 and the drainage passage 21
A piston 23 for partitioning into, a throttle passage 24 formed in the piston 23 for communicating the first liquid chamber 20 and the second liquid chamber 22, a poppet 30 for opening and closing the liquid passage 25, and the liquid passage 15 Urging means 31 for urging the poppet 30 so as to close, and piston urging means 26 for urging the poppet 30 through the piston 23 so as to open the liquid passage 15.
And

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device capable of appropriately controlling a brake fluid pressure for a wheel cylinder, and is particularly suitable for being incorporated in an antilock braking system.

[0002]

2. Description of the Related Art An anti-lock braking system (hereinafter referred to as ABS) prevents a wheel from being locked during the operation of a brake, so that when the wheel is in a locked state, the wheel is locked. The brake force is temporarily reduced and the wheels are released from the locked state.Brake fluid pressure that switches the supply and discharge of brake fluid between the hydraulic pump dedicated to the anti-lock mechanism and the wheel cylinder of the brake. A control device is provided for each wheel, the hydraulic pump described above is driven by an electric motor, and the brake hydraulic pressure control device corresponding to this is activated according to the lock state of each wheel, and the brake fluid is supplied to the wheel cylinder of the brake. Adjusting pressure.

Conventionally, as a brake fluid pressure control device for this type of ABS, those disclosed in Japanese Patent Application Laid-Open No. 2-24254 and Japanese Utility Model Laid-Open No. 6-12241 are known.

The brake fluid pressure control device disclosed in Japanese Unexamined Patent Publication No. 2-24254 discloses a master cylinder that outputs a brake fluid pressure corresponding to an operator's operation, and a brake fluid pressure from the master cylinder is adjusted to boost the pressure. Pressure booster, a wheel cylinder operated by the brake fluid pressure supplied from the master cylinder, a flow control valve that communicates with the master cylinder, the hydraulic booster, and the wheel cylinder via fluid passages, and this flow rate. The pressure reducing solenoid valve communicates with the adjusting valve and communicates with the reservoir side via the discharge passage, and the flow rate of the brake fluid in the flow rate adjusting valve is adjusted by sliding the spool. .

The brake fluid pressure control device disclosed in Japanese Utility Model Laid-Open No. 6-12241 uses a master cylinder that outputs a brake fluid pressure corresponding to an operator's operation and a brake fluid pressure supplied from the master cylinder. A wheel cylinder that operates, a switching control valve that communicates with the master cylinder and the wheel cylinder via liquid passages, and a decompression electromagnetic on-off valve that communicates with the switching control valve and also communicates with the reservoir side through a discharge passage. The flow rate of the brake fluid in the switching control valve is adjusted by using the on-off valve and the piston.

[0006]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2-24254
The structure of the spool in the flow rate adjusting valve of the brake fluid pressure control device disclosed in Japanese Patent Publication requires strict machining accuracy in fluid tightness during sliding, alignment with fluid passages, etc. It is also accompanied.

In this regard, in the brake fluid pressure control device disclosed in Japanese Utility Model Laid-Open No. 6-12241, a switching control valve for adjusting the flow rate of a fluid passage between a master cylinder and a wheel cylinder is constituted by an on-off valve and a piston. Therefore, it is possible to realize a switching control valve that does not require high processing accuracy, and it is possible to suppress an increase in manufacturing cost as compared with the brake fluid pressure control device disclosed in JP-A-2-24254.

However, in the brake fluid pressure control device disclosed in Japanese Utility Model Laid-Open No. 6-12241, since the second opening / closing valve is incorporated in the piston, the number of parts is increased and the manufacturing cost is increased in terms of assemblability. It is bulky and there is room for improvement.

[0009]

A brake fluid pressure control device according to a first aspect of the present invention is a fluid for connecting a master cylinder for generating a brake fluid pressure corresponding to an operation of an operator and a wheel cylinder operated by the brake fluid pressure. Passage, a switching control valve provided in the fluid passage for controlling the brake fluid pressure for the wheel cylinder, a drainage passage connected to the switching control valve, and the drainage passage provided in the drainage passage. And a valve control means for controlling the on-off valve so as to open and close the drainage passage at the time of antilock brake operation while closing the drainage passage at the time of normal brake operation In the control device, the switching control valve is slidably fitted in a housing, one end of which communicates with the liquid passage and the other end of which communicates with the drainage passage. And a piston that partitions the inside of the housing into a first liquid chamber that communicates with the liquid passage and a second liquid chamber that communicates with the drainage passage, and the piston formed in the piston and the first liquid chamber and the piston. A throttle passage that communicates with a second liquid chamber, a poppet that can contact the piston and that opens and closes the liquid passage between the first liquid chamber and the master cylinder, and the master cylinder. And a poppet biasing means for biasing the poppet so as to close the liquid passage between the first liquid chamber and the first liquid chamber, and the master cylinder and the master cylinder with a biasing force larger than the biasing force of the poppet biasing means. Piston urging means capable of urging the poppet via the piston so as to open the liquid path between the first liquid chamber and the first liquid chamber.

A brake fluid pressure control device according to a second aspect is the brake fluid pressure control device according to the first aspect,
The poppet is characterized in that a throttle passage is formed which functions when the poppet closes the liquid passage between the master cylinder and the first liquid chamber.

[0011]

According to the brake fluid pressure control device of the first aspect, during normal brake operation, the valve control means operates the on-off valve so as to close the drainage passage, and the poppet is mastered by the piston urging means. It is biased via the piston to open the liquid path between the cylinder and the first liquid chamber. Therefore, the brake fluid from the master cylinder that generates the brake fluid pressure corresponding to the operation of the operator is introduced from the fluid passage to the wheel cylinder through the first fluid chamber of the housing, and the brake is activated.

When the ABS is in a locked state during operation of the ABS, the valve control means operates the on-off valve to open the drainage passage. When the brake fluid from the master cylinder that generates the brake fluid pressure corresponding to the operation of the operator is introduced into the first fluid chamber of the housing, the second fluid chamber communicating with the first fluid chamber and the drainage passage. Since a pressure difference occurs between and,
The piston is pressed against the second liquid chamber side against the piston urging means, and as the piston moves, the poppet occludes the liquid passage by the poppet urging means. As a result, the brake fluid pressure in the wheel cylinder rises. Is suppressed, and the brake fluid is gradually discharged from the first fluid chamber to the second fluid chamber through the throttle passage of the piston.

When the wheel comes out of the locked state,
The valve control means operates the on-off valve so as to close the drainage path.
As a result, the piston urging means functions and the piston is pushed back toward the first fluid chamber side, the poppet opens the fluid path between the master cylinder and the first fluid chamber, and the brake fluid from the master cylinder reopens. It is introduced into the first liquid chamber of the housing.

According to the brake fluid pressure control device of the second aspect, the piston moves to the second fluid chamber side of the housing, and the fluid passage between the master cylinder and the first fluid chamber is provided by the poppet urging means. Even when the poppet is blocked, the high-pressure brake fluid continues to be supplied to the first fluid chamber from the throttle passage of the poppet, and the decrease rate of the brake fluid pressure in the first fluid chamber is moderated.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a brake fluid pressure control device according to the present invention will be described in detail below with reference to FIG. 1 showing the concept of the mechanism and FIG.

A brake pedal 14 operated by a driver (not shown) is connected to a master cylinder 13 provided with a reservoir tank 12 for storing the brake fluid 11. A switching control valve 16 is connected to the master cylinder 13 that outputs a brake fluid pressure corresponding to the depression amount of the brake pedal 14 via a first fluid passage 15. A wheel cylinder 18 is connected to the switching control valve 16 via a second liquid passage 17, and the wheel cylinder 18 extends from the master cylinder 13 to the first liquid passage 1.
5, it operates by the brake fluid pressure supplied through the switching control valve 16 and the second fluid passage 17, and brakes the wheels (not shown).

The master cylinder 13 in this embodiment is
It is a tandem type cylinder having two independent pressurizing chambers, and the brake fluid pressures generated in these two pressurizing chambers are mutually independent pipes forming the first fluid passages 15 to form front wheels of the vehicle. And to the wheel cylinders 18 of each brake of the rear wheels. FIG. 1 shows only a system corresponding to the wheel cylinder 18 of one of the wheels.

The housing 19 of the switching control valve 16 has a first liquid chamber 20 whose one end faces the first and second liquid passages 15 and 17, and a second liquid chamber whose other end faces the drain passage 21. A chamber 22 is formed. The first liquid chamber 20 and the second liquid chamber 22 are partitioned by a piston 23 slidably accommodated in the housing 19. A throttle passage 24 that connects the first liquid chamber 20 and the second liquid chamber 22 is formed in the piston 23.
A stopper 25 is formed at the other end of the housing 19 and projects toward the second liquid chamber 22 to define the stroke end of the piston 23 on the second liquid chamber 22 side. Further, a compression spring 26 for urging the piston 23 toward the first liquid chamber 20 is incorporated in the second liquid chamber 22 as piston urging means of the present invention.

The piston 2 facing the first liquid chamber 20
In the state shown in FIG. 1 in which one end surface (upper end surface in the figure) of 3 is in contact with the inner end surface of the housing 19 on the first liquid chamber 20 side, that is, at one stroke end of the piston 23, the first liquid In order to prevent the connection port 27 of the first liquid passage 15 to the chamber 20 from being blocked by one end surface of the piston 23, one end surface of this piston 23 is
A cutout portion 28 is formed for always communicating the first liquid chamber 20 and the connection port 27. Similarly, when the other end surface (lower end surface in the figure) of the piston 23 facing the second liquid chamber 22 is in contact with the tip of the stopper 25, that is, at the other stroke end of the piston 23, the throttle passage 24 is The other end surface of the piston 23 is provided on the other end surface thereof so as not to be blocked by the other end surface of the piston 23.
A cutout portion 29 is formed so that the drainage passage 21 and the throttle passage 24 can always be communicated with each other.

The connection port 27 of the first liquid passage 15 for the first liquid chamber 20 accommodates a poppet 30 capable of opening and closing the connection port 27. When the piston 23 is biased toward the first liquid chamber 20 by the spring force of the compression spring 26, the lower end of the poppet 30 contacts one end face of the piston 23 and is pushed upward in the figure. The connection port 27 is opened. A compression spring 31 for urging one end of the poppet 30 so as to close the connection port 27 is accommodated in the connection port 27 as poppet urging means of the present invention. It is set to be smaller than the spring force of the compression spring 26 of the piston 23. Therefore, the piston 23
Connection port 27 unless is moved to the second liquid chamber 22 side.
Is held in an open state, and when the piston 23 moves toward the second liquid chamber 22 side by a predetermined stroke or more, the connection port 27 is closed by the spring force of the compression spring 31.
It is supposed to be blocked by.

The wheel cylinder 1 is operated during ABS operation.
Since the pressure increase control for slowly increasing the brake fluid pressure is performed with respect to 8, the communication state between the first fluid chamber 20 and the connection port 27 is ensured when the poppet 30 closes the connection port 27. Thus, the poppet 30 is formed with a notch-shaped throttle passage 32.

A reservoir 33 is connected to the other end of the drainage passage 21 whose one end is connected to the second liquid chamber 22, and the brake fluid in the second liquid chamber 22 is discharged into this reservoir 33. It is like this. In addition, an electromagnetic on-off valve 34 which is closed when not energized and which opens and closes the drainage path 21 is provided in the middle of the drainage path 21, and the electromagnetic on-off valve 34 is based on a command from the control unit 35. The energization state can be switched. Further, the reservoir 33 and the solenoid on-off valve 3
A throttle 36 is provided in the drainage path 21 between the diaphragm 4 and the drainage tank 4.

A brake fluid supply pipe 3 having one end connected to the middle of the first fluid passage 15 and the other end connected to the reservoir 33.
A brake fluid pump 38 for pumping the brake fluid in the reservoir 33 to the first fluid passage 15 side is provided in the middle of 7, and the brake fluid pump 38 is based on a command from the control unit 35. Electric motor 39
Driven by. The brake fluid is supplied to the brake fluid supply pipes 37 on the upstream side and the downstream side of the brake fluid pump 38, that is, from the first fluid passage 15 side to the reservoir 33.
Check valves 40 and 41, which prevent the flow of the brake to the side, are respectively interposed.

The control unit 35 switches ON / OFF of energization of the electromagnetic opening / closing valve 34 and the electric motor 39 according to a preset driving condition of the vehicle. In the present embodiment, the electromagnetic on-off valve 34 and the electric motor 39 are kept in the non-energized state during the normal brake operation, and the opening / closing operation of the electromagnetic on-off valve 34 is repeated as needed during the ABS operation and the electric motor 39 is also performed. Is kept energized.

Therefore, at the time of normal brake operation, as shown in FIG.
As shown in, the electromagnetic opening / closing valve 34 is in a state in which the drainage passage 21 is closed. Then, since the inside of the second liquid chamber 22 is sealed, the piston 23 is held at one stroke end by the spring force of the compression spring 26. In this state, when the driver who is the operator depresses the brake pedal 14, a predetermined brake fluid pressure is generated in the master cylinder 13. At this time, the poppet 30 moves the first liquid passage 1 by the spring force of the compression spring 26 via the piston 23.
Since 5 is opened, this brake fluid pressure is supplied from the first fluid passage 15 to the wheel cylinder 18 through the first fluid chamber 20 and the second fluid passage 17 of the switching control valve 16.

When the brake pedal 14 is released, the master cylinder 13 and the wheel cylinder 1 are released.
8 is in communication with the wheel cylinder 1
The brake fluid pressure in 8 is returned to the master cylinder 13 side,
The pressure in the wheel cylinder 18 is reduced.

On the other hand, when the wheels (not shown) tend to lock during the normal brake operation, the ABS control is started.
That is, when the wheels become locked, the control unit 3
Reference numeral 5 excites the electromagnetic opening / closing valve 34 to open the drainage passage 21, while the control unit 35 energizes the electric motor 39 to operate the brake fluid pump 38. This allows
Since the brake fluid in the reservoir 33 is pumped up and the brake fluid pressure in the second fluid chamber 22, the drainage passage 21 and the reservoir 33 decreases, the first fluid chamber 20 and the second fluid chamber 2
The piston 23 starts to move toward the second liquid chamber 22 side against the spring force of the compression spring 26 due to the pressure difference between the piston 23 and the piston 23. The moving speed of the piston 23 can be adjusted to a desired value by appropriately setting the sectional areas of the throttle passage 24 and the throttle 36.

In this way, when the piston 23 starts moving to the second liquid chamber 22 side, the poppet 30 moves to the piston 2
With the downward movement of 3, the spring force of the compression spring 31 moves to the first liquid chamber 20 side to close the connection port 27. If the piston 23 continues to move to the second liquid chamber 22 side from this time point, the brake hydraulic pressure in the first liquid chamber 20, the second liquid passage 17, and the wheel cylinder 18 starts to decrease, locking the wheels. Restore from a mild state. In this case, the brake fluid from the connection port 27 side is supplied to the first fluid chamber 20 through the throttle passage 32 of the poppet 30, but the volume of the first fluid chamber 20 increases due to the movement of the piston 23. Since the ratio is larger, the brake fluid pressure in the wheel cylinder 18 can be reliably reduced. Further, the brake fluid pumped up by the brake fluid pump 38 is pressurized and recirculated from the brake fluid supply pipe 37 into the first fluid passage 15.

When the wheel is returned from the locked state and the brake fluid pressure in the wheel cylinder 18 is increased again as the brake fluid pressure in the wheel cylinder 18 decreases, the control unit 35 does not turn on the electromagnetic opening / closing valve 34. The drainage path 21 is closed by shifting to the energized state. As a result, the piston 23 starts to move toward the first liquid chamber 20 side by the spring force of the compression spring 26, the brake fluid pressure in the first liquid chamber 20 slowly rises, and the braking force by the wheel cylinder 18 is thereby increased. Correspondingly, the gradual pressure increase control is performed to recover gradually.
Then, one end surface of the piston 23 presses against the poppet 30, and resists the spring force of the compression spring 31 to push the poppet 30.
When pushing back into the connection port 27, the first liquid passage 1
A large amount of high-pressure brake fluid in 5 flows into the first fluid chamber 20, the brake fluid pressure in the wheel cylinder 18 rises sharply, and the braking force on the wheels rapidly increases.

In this way, the energization of the electromagnetic on-off valve 34 is switched on / off according to the rotation state of the wheel, and efficient braking operation is performed.

[0031]

According to the brake fluid pressure control device of the first aspect, the first fluid chamber and the drainage passage, which are slidably fitted in the housing and communicate with the fluid passage in the housing, communicate with each other. In the piston that is partitioned into the second liquid chamber to be formed, since a throttle passage that connects the first liquid chamber and the second liquid chamber to each other is formed,
It is possible to easily realize a switching control valve that has a small number of parts and does not require high processing accuracy, and suppress an increase in manufacturing cost.

According to the brake fluid pressure control device of the second aspect, since the poppet has the throttle passage functioning in a state where the fluid passage between the master cylinder and the first fluid chamber is closed, the poppet is formed. It is possible to start increasing the brake fluid pressure very slowly with respect to the wheel cylinder after depressurization.

[Brief description of drawings]

FIG. 1 is a mechanism conceptual diagram showing a state during normal brake operation in an embodiment of a brake fluid pressure control device according to the present invention.

FIG. 2 is a mechanism conceptual diagram showing a state during ABS operation in the embodiment shown in FIG.

[Explanation of symbols]

 11 Brake Fluid 12 Reservoir Tank 13 Master Cylinder 14 Brake Pedal 15 First Fluid Channel 16 Switching Control Valve 17 Second Fluid Channel 18 Wheel Cylinder 19 Housing 20 First Fluid Chamber 21 Drainage Channel 22 Second Fluid Chamber 23 Piston 24 Throttling passage 25 Stopper 26 Compression spring 27 Connection port 28, 29 Notch portion 30 Poppet 31 Compression spring 32 Throttling passage 33 Reservoir 34 Electromagnetic on-off valve 35 Control unit 36 Throttling 37 Brake fluid supply pipe 38 Brake fluid pump 39 Electric motor 40 , 41 Check valve

Claims (2)

[Claims] 1. A fluid passage connecting a master cylinder for generating a brake fluid pressure corresponding to an operator's operation and a wheel cylinder operated by the brake fluid pressure, and a brake fluid pressure for the wheel cylinder provided in the fluid passage. Control valve, a drainage passage connected to the changeover control valve, an opening / closing valve provided in the drainage passage for opening and closing the drainage passage, and the drainage passage during normal brake operation. On the other hand, in a brake fluid pressure control device having a valve control means for controlling the opening / closing valve so as to open / close the drainage passage when the antilock brake is operated, the switching control valve has one end side communicating with the fluid passage. And a housing in which the other end communicates with the drainage passage, and a first liquid chamber which is slidably fitted in the housing and communicates with the liquid passage in the housing. And a piston for partitioning into a second liquid chamber communicating with the drainage passage, a throttle passage formed in the piston for communicating the first liquid chamber and the second liquid chamber with each other, the piston And a poppet for opening and closing the liquid passage between the first liquid chamber and the master cylinder, and closing the liquid passage between the master cylinder and the first liquid chamber. A poppet urging means for urging the poppet, and a urging force larger than the urging force of the poppet urging means to open the liquid passage between the master cylinder and the first liquid chamber. A brake fluid pressure control device comprising: a piston urging means capable of urging the poppet via a piston. 2. The poppet is formed with a throttle passage that functions when the poppet closes the liquid passage between the master cylinder and the first liquid chamber.
Brake fluid pressure control device described in.