JPH05319237A - Hydraulic control device for antilock brake unit - Google Patents

Abstract

PURPOSE:To easily perform manufacture while securing the safety of a driver. CONSTITUTION:A supply path 24 for guiding brake fluid from a master cylinder 2, main discharge path and a subdischarge path 27 for discharging the brake fluid are formed in a casing 20 of a flow regulating valve 10. In the subdischarge path, a throttle 28 for limiting the brake fluid of flowing in this subdischarge flow path is provided. A receiving port possible to accept the brake fluid from the supply path 24 and a main discharge port and subdischarge port connected to the receiving port are formed in a reciprocatably provided spool 11. There are connected the subdischarge path 27 to a wheel cylinder 6, main discharge path 26 to the first port 31 connected to the second port 32 of a three-way valve 30 in a condition that a wheel is not locked, second port to wheel cylinder 6 and the third port 33, communicating with the second port 32 in the case of locking the wheel, to a reservoir 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is
The present invention relates to a hydraulic control device of an anti-lock brake device that can release a lock by reducing a brake fluid pressure in a wheel cylinder that applies a braking force to a wheel.

[0002]

2. Description of the Related Art As a conventional antilock brake device (hereinafter referred to as ABS), for example, Japanese Patent Laid-Open No. 61-
Some are disclosed in Japanese Patent No. 263860. This ABS is provided with a flow rate control valve for controlling the flow rate of the brake fluid supplied to the wheel cylinders, and a pressure reducing solenoid valve for discharging the brake fluid supplied to the wheel cylinders via the flow rate control valve.

In this ABS, during normal braking, the spool in the flow rate control valve is pressed by the spring, and the master cylinder, which is the supply source of brake fluid, and the wheel cylinder are in direct communication with each other. .. During the ABS operation, when the wheel lock state is detected, the pressure reducing solenoid valve operates and the brake fluid in the spool flows to the reservoir. At this time, since the brake fluid is depressurized when passing through the fixed orifice in the spool, a pressure difference is generated between the upstream side and the downstream side of the fixed orifice, the spool moves to the downstream side, and communicates during normal braking. The main flow path between the master cylinder and the wheel cylinder is blocked, and the wheel cylinder and the reservoir are in communication with each other via the spool. In such a state, the brake fluid in the wheel cylinder flows to the reservoir, and the wheel cylinder is depressurized. Therefore, the locked state of the wheels can be avoided.

However, in this ABS, since there is only one flow path between the wheel cylinder and the master cylinder, if the spool sticks due to foreign matter entering from the outside, braking operation or ABS operation cannot be performed. Such a state must be avoided by all means as a braking device that requires sufficient consideration for ensuring safety.

In view of this, there is one described in Japanese Patent Laid-Open No. 102857/1990 in consideration of this point. As shown in FIG. 6, this ABS forms a main flow path 8 and a sub flow path 9 that allow the master cylinder 2 and the wheel cylinder 6 to communicate with each other in the flow control valve, and even if the spool sticks. It is configured such that either one of the flow paths can be secured. The ABS sub-flow path 9 is provided with two fixed orifices 7a and 7b. One orifice 7a is provided in the spool, and the other orifice 7b is provided in a casing that accommodates the spool in a reciprocating manner. Has been. The reason why the two fixed orifices are provided is that a pressure difference is generated between the upstream side and the downstream side of the orifice in order to reciprocate the spool. That is, with one orifice, the upstream side and the downstream side of the orifice are in communication with the main flow path 8, so that there is no pressure difference between the upstream side and the downstream side of the orifice, and the spool cannot reciprocate. Because.

By the way, one of the orifices 7a in the spool has a role of determining the flow rate at the time of repressurization, and
Its inner diameter needs to be smaller than the inner diameter of the other orifice 7b. This is because it is necessary to flow more brake fluid in the wheel cylinder 6 to the reservoir 4 than the brake fluid from the master cylinder 2 when the ABS function is activated.

[0007]

However, in such a conventional technique, one of the two fixed orifices 7a, 7b having a minute inner diameter through which a minute amount of the brake fluid flows, as described above, one of the orifices 7a is It has a role of determining the flow rate at the time of repressurization, and its inner diameter needs to be smaller than the inner diameter of the other orifice 7b, and such a restriction is applied to a fixed orifice having a minute inner diameter through which a minute amount of brake fluid flows. It is very difficult to process, and even if it can be processed, even if it can be processed, it will not function as an ABS because it adheres to a very small foreign substance or an orifice, making it difficult to use as an actual product. There is a point. Further, since the two fixed orifices 7a and 7b are used, there is a high possibility that foreign matter will stick.

The present invention has been made by paying attention to such a conventional problem, and it is possible to secure the driver's safety even if the spool sticks, and the ABS is easy to manufacture. An object is to provide a hydraulic control device and a flow rate control valve thereof.

[0009]

An ABS hydraulic control device for achieving the above object includes a master cylinder for generating a brake fluid pressure in response to an operation of a brake pedal, and a brake fluid pressure from the master cylinder. A wheel cylinder for applying a braking force to the wheels, a flow rate control valve for controlling the flow rate of the brake fluid, a reservoir for temporarily storing the brake fluid, and three ports, and whether the wheel is in a locked state A three-way valve that switches the flow path depending on whether or not the spool is biased to one side of the flow rate control valve so as to be capable of reciprocating in a casing that accommodates the spool. Is formed with a supply passage for guiding the brake fluid from the master cylinder into it, and a main discharge passage and a sub discharge passage for discharging the brake fluid therein. A throttle for limiting the flow rate of the brake fluid flowing therethrough is provided in the sub discharge path, and the one of the two spaces of the casing formed by being partitioned by the spool is A pressure equalizing passage for equalizing the brake fluid pressure in the other space on the opposite side to the brake fluid pressure in a portion of the auxiliary discharge passage on the downstream side of the throttle is formed, and in the spool, When the spool is located at the other end of the reciprocating range, it is almost impossible to internally receive the brake fluid from the supply passage, and the spool is located at another position. A receiving port capable of receiving the brake fluid from the supply passage therein, a receiving port communicating with the receiving port, and the spool positioned at least at the one end of the reciprocating range. The main discharge port communicating with the main discharge passage and the receiving port are communicated with each other, and no matter where the spool is located in the reciprocating range, the main discharge passage communicates with the sub discharge passage. An auxiliary discharge port is formed, the auxiliary discharge path of the flow rate control valve is connected to the wheel cylinder, and the main discharge path of the flow rate control valve is one of the three ports of the three-way valve.
Of the three ports of the three-way valve, the second port of the three-way valve is connected to the first port that communicates with the second port when the wheel is not locked, and the second port of the three-way valve is connected to the front wheel cylinder. The third port, which communicates with the second port when the wheel is locked, is connected to the reservoir.

Here, it is preferable that a pressure buffering means for changing the pressure of the brake fluid is provided between the master cylinder and the receiving port of the spool. Specific examples of the pressure buffering means include a throttle for narrowing the flow path of the brake fluid, a welding chamber provided in communication with the flow path of the brake fluid, and the like.

Further, it is preferable that the throttle provided in the auxiliary discharge passage is detachably provided in the casing.

[0012]

During normal braking, the spool biased to one side is positioned at one end of its reciprocating range (hereinafter referred to as the normal braking position). Therefore, the supply path of the casing and the receiving port of the spool, and the main discharge port of the spool and the main discharge path of the casing are in communication with each other. Further, the three-way valve is in a state where the first port and the second port communicate with each other, and the main discharge passage of the flow rate control valve and the wheel cylinder are in communication with each other via the three-way valve. At this time, when the brake pedal is stepped on and the brake fluid pressure in the master cylinder rises, the brake fluid flows into the inside from the supply passage of the flow rate control valve, and the spool inlet,
Through the main outlet, out of the main outlet of the casing,
It flows into the wheel cylinder via a three-way valve. When the brake fluid flows into the wheel cylinder, the internal pressure of the brake fluid rises and braking force is applied to the wheels.

Since the sub discharge port of the spool and the sub discharge passage of the casing are always in communication with each other, the brake fluid that has entered from the supply passage to the sub discharge passage passes through the spool receiving port and the sub discharge passage. It flows through the discharge passage and flows into the wheel cylinder. However, since there is a throttle in the auxiliary discharge path and the flow path resistance here is larger than the flow path resistance on the main discharge path side, most of the brake fluid that has entered the inside from the supply path passes through the main discharge path side and the wheel cylinder. Flow into. Also,
Since the upstream side and the downstream side of the throttle of the auxiliary discharge passage are connected to the main discharge passage side, respectively, there is almost no pressure difference between the upstream side and the downstream side. Therefore, there is almost no pressure difference between the brake fluid pressure in the flow path in the spool upstream of the throttle and the brake fluid pressure in the other space in the casing, and the force acting in the reciprocating direction on the spool excludes the biasing force. Since they are approximately equal, the spool maintains the normal braking position.

When the wheels are locked, the first port of the three-way valve is shut off and the second port and the third port are in communication.
Therefore, the flow path on the main discharge path side of the flow control valve is disconnected from the wheel cylinder, and the wheel cylinder and the reservoir communicate with each other.

The brake fluid from the master cylinder is supplied from the supply path through the spool receiving port and the sub discharge port.
It is discharged from the secondary discharge path. At this time, since the flow path on the main discharge path side is blocked, a pressure difference occurs between the upstream side and the downstream side of the throttle of the sub discharge path. As a result of the pressure difference between the upstream side and the downstream side of the throttle, a pressure difference occurs between the brake fluid pressure in the spool internal flow passage on the upstream side of the throttle and the brake fluid pressure in the other space in the casing. Move in the other direction until the urging force acting in the direction of and the hydraulic pressure generated by this pressure difference become equal. Therefore, the flow passage area of the connecting portion between the supply passage of the casing and the receiving port of the spool is gradually reduced, and the brake fluid supplied from the master cylinder is gradually reduced. Further, since the wheel cylinder and the reservoir are in communication, the brake fluid in the wheel cylinder flows to the reservoir, the fluid pressure in the wheel cylinder drops, and the wheel lock is released.

When the wheels are unlocked, the three-way valve
Again, the first port and the second port communicate with each other, and normal braking can be performed.

By the way, in the present invention, since the brake fluid flow passage from the master cylinder to the wheel cylinder includes the main discharge passage side passage and the sub discharge passage side passage, even if the spool sticks at a certain position, Normal braking and ABS operation can be reliably performed. Further, in the present invention, since a three-way valve is provided in the flow path on the main discharge path side to cut off the flow on the main discharge path side, a pressure difference is generated between the upstream side and the downstream side of the throttle of the sub discharge path. Therefore (to move the spool), it is not necessary to provide two fixed throttles having a small inner diameter in the flow path on the side of the secondary discharge path.

[0018]

EXAMPLE An AB according to the present invention will be described below with reference to FIGS.
Various examples of S will be described. First, the ABS of the first embodiment according to the present invention will be described with reference to FIGS. As shown in FIG. 1 and FIG. 4, the ABS of this embodiment includes a master cylinder 2 that is interlocked with a brake pedal 1, a wheel cylinder 6 that brakes wheels, and a flow rate of brake fluid supplied from the master cylinder 2. Flow control valve 10, a three-way solenoid valve 30, a reservoir 4 for temporarily storing brake fluid, a pump 3 for returning the brake fluid in the reservoir 4 to the master cylinder 2 side, and a pump for driving this pump 3. The drive motor 3a, a lock state detection sensor 49 that detects whether or not the wheel is in a lock state based on the movement of the wheels, and the three-way solenoid valve 30 and the pump drive motor 3a are operated based on a signal from the lock state detection sensor 49. And a control unit 40.

The flow rate control valve 10 includes a spool 11, a casing 20 which accommodates the spool 11 so as to be capable of reciprocating,
And a spring 29 that biases the spool 11 in one direction. The casing 20 is provided with a supply passage 24 for supplying the brake fluid from the master cylinder 2 into the spool housing chamber 21 in which the spool 11 is provided, and for feeding the brake fluid in the spool housing chamber 21 to the three-way solenoid valve 30. The main discharge passage 26, the sub discharge passage 27 for discharging the brake fluid in the spool chamber 21, and the spool storage chamber 2
A side where the first spring 29 is provided, that is, a pressure equalizing path 29a for balancing the pressure between the spring chamber 22 and a second main discharge pipe 53 described later is formed. Spool 11
Includes an annular path 12 provided on the outer periphery of the spool 11 substantially at the center, a first radial path 13 penetrating the annular path 12 in the radial direction of the spool 11, and a center of the first radial path. Portion of the spool housing chamber 21 from which the spring 29 is not provided, that is, the axial path 1 penetrating the back pressure chamber 23.
4 and a second radial path 15 passing through this axial path 14 and penetrating in the radial direction of the spool 11 are formed. The auxiliary discharge passage 27 is formed such that its flow passage area is smaller than the flow passage areas of the other flow passages in the flow rate control valve 10.

In relation to the supply passage 24 of the casing 20, the annular passage 12 of the spool 11 is disconnected from the supply passage 24 when the spool 11 moves to the most spring chamber 22 side (state of FIG. 3). Sauce, secondary discharge path 27 of casing 20
In relation to, the spool 11 is formed so as to communicate with the auxiliary discharge passage 27 at any position. Also,
In the second radial passage 15, the spool 11 is the most back pressure chamber 2.
When the spool 11 moves to the side 3 (state of FIG. 1), it is in communication with the main discharge path 26 of the casing 20, and while the spool 11 is moving to the side of the spring chamber 22 (state of FIG. 2), main discharge It is formed so as to be disconnected from the passage 26.

In the supply passage 24 of the casing 20, when the brake pedal 1 is suddenly depressed, a pressure that changes abruptly (at this time, the pressure distribution in the supply passage 24 becomes a spike) is buffered so as not to be applied to the spool 11. Entrance fixed throttle 2
5 are provided. Since the inlet fixed throttle 25 is only for buffering, it is not necessary to reduce the inner diameter so much that the flow passage area and the flow passage area of the three-way solenoid valve 30 are substantially the same here. An inlet fixed throttle 25 is formed. Further, in the auxiliary discharge passage 27 of the casing 20, the flow rate of the brake fluid flowing therethrough is adjusted, and a pressure difference is formed between the upstream side and the downstream side thereof, so that the spring chamber 22 and the back pressure chamber 23 are formed. An outlet fixed throttle 28 for generating a pressure difference and moving the spool 11 is provided.

The master cylinder 2 and the supply passage 24 of the flow control valve 10 are connected by a supply pipe 51. The main discharge passage 26 of the flow rate control valve 10 and the first port 31 of the three-way solenoid valve 30 are connected by a first main discharge pipe 52. The second port 32 of the three-way solenoid valve 30 and the wheel cylinder 6 are connected by the second main discharge pipe 53.
The third port 33 of the three-way solenoid valve 30 is connected to the circulation pipe 56, and the circulation pipe 56 is connected to the supply pipe 51 via the reservoir 4 and the pump 3. Although not shown, a suction valve and a discharge valve are provided on the suction side and the discharge side of the pump 3 of the circulation pipe 56, respectively. Sub discharge passage 28 and pressure equalizing passage 29a of the flow rate control valve 10
Is connected to the second discharge pipe 54 and the pressure equalizing pipe 55, respectively.
Of the main discharge pipe 53.

Although not shown, the control unit 40 has a CPU, a ROM, a RAM, and an I / O port. R of control unit 40
The OM stores a program for operating the three-way solenoid valve 30 and the pump driving motor 3a based on the signal from the lock state detection sensor 49.

Next, the operation of this embodiment will be described.
First, the operation during normal braking will be described with reference to FIG. During normal braking, the spool 11 is in the spool storage chamber 21.
Is located at the end portion of the back pressure chamber 23 side (hereinafter, this position is referred to as a normal braking position), and the supply passage 2 of the casing 20.
4 and the main discharge passage 26 are in communication with each other via the annular passage 12 of the spool 11, the first radial passage 13, the axial passage 14, and the second radial passage 15. In addition, the supply path 2
4 and the auxiliary discharge passage 27 are in communication with each other via the annular passage 12 and the first radial passage 13. The three-way solenoid valve 30 has the first port 31 and the second port 32 in communication with each other.

When the driver steps on the brake pedal 1, the brake fluid in the master cylinder 2 is pressurized, and the brake fluid flows into the supply passage 24 of the flow control valve 10 via the supply pipe 51. As shown in FIG. 4, the brake fluid flowing into the supply passage 24 is divided into two systems by the spool 11, one of which is the annular passage 12 and the first radial passage 1.
3, through the axial passage 14 and the second radial passage 15, flowing out of the main discharge passage 26 of the casing 20, and the other through the annular passage 12 of the spool 11 and flowing out of the auxiliary discharge passage 27 of the casing 20. The brake fluid flowing out from the main discharge passage 26 of the casing 20 passes through the first main discharge pipe 52, the first port 31, the second port 32, and the second main discharge pipe 53 of the three-way solenoid valve 30, and then passes through the wheel cylinder 12 Is supplied to. Further, the brake fluid flowing out from the sub discharge passage 27 of the casing 20 is also supplied to the wheel cylinder 12 through the second main discharge pipe 53.

At this time, since the outlet fixed throttle 28 is provided in the auxiliary discharge passage 27 of the casing 20, the flow passage resistance here is larger than the flow passage resistance of the main discharge passage 26. Most of the brake fluid that has flowed into 24 passes through the main discharge passage 26, and is supplied to the wheel cylinder 6 via the three-way solenoid valve 30 and the second main discharge pipe 53.

The upstream side and the downstream side of the outlet fixed throttle 28 are connected to the spool 11, the main discharge passage 26 of the casing 20,
Since they are connected via the three-way solenoid valve 30 and the second main discharge passage 53, there is almost no pressure difference between the upstream side and the downstream side of the outlet fixed throttle 28. Therefore, the outlet fixed throttle 2
8, there is almost no pressure difference between the spring chamber 22 connected to the downstream side and the upstream side of the outlet fixed throttle 28, and the flow paths 12, 13, ... The spring 29 pushes the spring 29 to maintain the normal braking position.

However, even in such a state, when the driver rapidly depresses the brake pedal 1, not only the outlet fixed throttle 28, but also 12, 13, ... Therefore, it is conceivable that a pressure difference occurs between the chambers on both sides of the spool 11 and the spool 11 moves. Therefore, in the present embodiment, the supply path 24
An inlet fixed throttle 25 for pressure buffering is provided on the spool 11 to suppress a sudden change in the pressure in the flow path, and the spool 11 can be operated during normal braking.
Is prevented from moving. Of course, since the inlet fixed throttle 25 is intended for pressure buffering,
It goes without saying that the same effect can be expected even if a volume chamber is provided in the supply path 24 instead.

Next, the operation of reducing the brake fluid pressure in the wheel cylinder 6 by the ABS function will be described with reference to FIGS.
Will be explained. When the wheels are locked during normal braking, the lock state detection sensor 49 detects this and outputs a lock detection signal to the control unit 40. The control unit 40 receives this signal and outputs a drive signal to the three-way solenoid valve 30 and the pump drive motor 3a. As a result, as shown in FIG. 2, the three-way electric valve 30 is driven, the first port 31 is shut off, and the second port 32 and the third port 33 are in communication. Three-way solenoid valve 30
When the second port 32 and the third port 33 of 3 communicate with each other, the second discharge pipe 53 and the circulation pipe 56 are connected. Therefore, the wheel cylinder 6 and the reservoir 4 are in communication with each other. Therefore, the brake fluid in the wheel cylinder 6 is
It flows into the reservoir 4 through the second discharge pipe 53, the three-way solenoid valve 30, and the circulation pipe 56, the pressure in the wheel cylinder 6 is reduced, and the locked state of the wheels is released. Further, since the pump 3 is also driven, the brake fluid flowing into the reservoir 4 passes through the circulation pipe 56 and returns to the supply pipe 51 again.

At this time, the brake fluid flowing from the supply passage 24 of the casing 20 flows out only from the auxiliary discharge passage 27 of the casing 20 because the first main discharge pipe 52 is blocked by the three-way solenoid valve 30. By the way, the upstream side and the downstream side of the outlet fixed throttle 28 of the sub discharge path 27 are different from those at the time of the normal braking described above, the spool 11, the main discharge path 26 of the casing 20, the three-way solenoid valve 30, and the second main discharge. Since they are not connected via the passage 53, a pressure difference occurs between the upstream side and the downstream side of the outlet fixed throttle 28. Therefore, the pressure in the flow passages 12, 13, ... Inside the spool 11 becomes larger than the pressure inside the spring chamber 22, and the spool 11 moves to the spring chamber 22 side.

This movement of the spool 11 disconnects the connection between the second radial passage 15 of the spool 11 and the main discharge passage 26 of the casing 20, as shown in FIG.
Supply path 24 of casing 20 and annular path 1 of spool 11
The flow path area of the connection portion with 2 becomes small. In addition, the movement of the spool 11 causes the spring 29 to contract and the spool 1
The force that urges 1 toward the back pressure chamber 23 side gradually increases. When the spool 11 further moves to the spring chamber side 22 and the connection between the supply passage 24 of the casing 20 and the annular passage 12 of the spool 11 is cut off as shown in FIG. 3, the brake fluid does not flow into the spool 11. Therefore, the brake fluid does not flow in the sub discharge passage 27, and there is no pressure difference between the upstream side and the downstream side of the outlet fixed throttle 28. Therefore, the force by which the spring 29 pushes the back pressure chamber 23 side and the force by which the brake fluid in the spool 11 pushes the spring chamber 22 side are balanced by the pressure difference between the upstream side and the downstream side of the outlet fixed throttle 28. Then, the spool 11 is stopped (hereinafter, this position is referred to as an ABS function operating position). The connection portion between the supply passage 24 of the casing 20 and the annular passage 12 of the spool 11 functions as a variable orifice, and adjusts the amount of brake fluid flowing into the passages 12, 13, ... Of the spool 11.

Next, the operation of canceling the ABS function will be described. When the lock state is released, the lock detection signal from the lock state detection sensor 49 disappears, and the signal from the control unit 40 causes the first port 31 and the third port of the three-way solenoid valve 30 to communicate with each other, and the pump. Driving of 3 stops. By this operation, the line through which the brake fluid flows through the three-way solenoid valve 30 to the reservoir 4 is cut off, so that all the brake fluid that has flowed into the flow rate control valve 10 will flow into the wheel cylinder 6. When the locked state is released, the internal pressure of the wheel cylinder 6 is low, but when the three-way solenoid valve 30 operates, the brake fluid begins to flow into the wheel cylinder 6 through the sub discharge passage 27, so the internal pressure here gradually rises. Come on. Therefore, the pressure difference between the upstream side and the downstream side of the outlet fixed throttle 28 becomes small, the spool 11 gradually moves to the back pressure chamber 23 side, and returns to the normal braking state.

Next, the operation when the spool 11 sticks in each state will be described. When the spool 11 sticks and is stuck to the normal braking position during normal braking, that is, when the spool 11 does not move in the state of FIG. 1, the flow passage from the supply passage 24 to the main discharge passage 26 is secured. Therefore, normal braking can be performed without any problems. Even when the wheels are locked in this state, when the three-way solenoid valve 30 is driven, the first port 31 is shut off, and the second port 32 and the third port 33 are connected, the brake in the wheel cylinder 6 is stopped. Since the liquid can flow into the reservoir 4, the lock of the wheel is surely released. However, in this case, since the spool 11 cannot move and the connecting portion between the supply passage 24 of the casing 20 and the annular passage 12 of the spool 11 does not function as a variable orifice, the brake fluid is flow passages 12, 13 ,. The amount that flows into is not reduced. As a result, the amount of the brake fluid flowing into the second main discharge pipe 53 through the auxiliary discharge passage 27 does not decrease, the internal pressure of the wheel cylinder 6 decreases slowly, and the unlocking operation becomes slow.

Further, the spool 11 is stuck at the ABS function operating position (however, the flow passage area of the connecting portion between the supply passage 24 of the casing 20 and the annular passage 12 of the spool 11 is small but surely secured). In this case, there is no problem in terms of ABS function. When the wheels are unlocked while the spool 11 is sticking at the ABS function operating position, the three-way solenoid valve 30 operates and the first port 3
1 and 2nd port 32 are open for free passage, and the 3rd port 33 to circulation pipe 56 is intercepted. In this case, even though the first port 31 and the second port 32 of the three-way solenoid valve 30 communicate with each other, the second radial passage 15 of the spool 11 and the main discharge passage 26 of the casing 20 do not communicate with each other. The main discharge path 26
Although the brake fluid does not flow to the side, since the flow path on the side of the secondary discharge passage 27 is secured, the normal braking operation can be surely performed. However, the brake fluid supplied from the master cylinder 2 to the wheel cylinders 6 will pass through the small flow passage at the connecting portion between the supply passage 24 of the casing 20 and the annular passage 12 of the spool 11, the outlet fixed throttle 28, and the flow rate. Is limited, resulting in a braking operation that is much slower than the driver intends.

As described above, in this embodiment, as shown in FIG. 4, the brake fluid flow passages from the master cylinder 2 to the wheel cylinders 6 are provided on the main discharge passage 26 side and the sub discharge passage 27 side. Since there is a flow path, even if the spool 11 sticks at a certain position, normal braking and ABS
The operation can be performed reliably. Further, in this embodiment,
As shown in FIG. 4, a three-way solenoid valve 30 is provided in the flow path on the side of the main discharge passage 26 to cut off the flow on the side of the main discharge passage 26. In order to generate a pressure difference (to move the spool 11), it is not necessary to provide two fixed throttles having a small inner diameter in the flow path on the side of the sub discharge path 27. For this reason, a small inner diameter of 2
It is not necessary to perform delicate processing on each fixed diaphragm in order to play different roles. Further, since only one fixed aperture 28 having a small inner diameter is required, there is a possibility that the side of the secondary discharge passage 27 may be blocked by foreign matter.
Can be reduced.

Next, the ABS according to the present invention will be described with reference to FIG.
A second embodiment will be described. In this embodiment, the same parts as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. In the first embodiment,
Only one outlet fixed throttle 28 with a small inner diameter is needed, and the secondary discharge path 2
Although there is little possibility that 7 will be blocked by a foreign substance, if this block is blocked, it will not be possible to perform a sufficient ABS function. Therefore, in this embodiment, the outlet fixed throttle 28 can be detached from the outside so that it can be easily maintained even if the outlet fixed throttle 28 having a small inner diameter is blocked by a foreign substance or the like. Therefore, the operation during normal braking and the operation content of the ABS function are the same as in the first embodiment.

In the present embodiment, an outlet fixed throttle 28a having a screw formed on the outer circumference is screwed in and installed on the upstream side of the bent portion of the auxiliary discharge passage 27a. Sub discharge path 27
An opening is formed on the extension line of the upstream side of the bent portion of a, and the sealing bolt 59 is screwed into the opening through the O-ring 58. With this configuration, even if the outlet fixed throttle 28a is closed, the sealing bolt 59 and the outlet fixed throttle 28a can be removed, and the outlet fixed throttle 28a can be cleaned or replaced. The blockage can be dealt with without exchanging the flow rate control valve 10a together.

In each of the above embodiments, the inlet fixed throttle 25 and the outlet fixed throttles 28, 28a are connected to the flow control valve 10.
However, these are not limited to these, and for example, the inlet fixed throttle 25 may be the supply pipe 51 and the outlet fixed throttles 28, 28a may be the auxiliary discharge pipe 5.
4 may be provided. Also, in the above various examples,
The pressure equalizing passage 29a of the casing 20 includes the pressure equalizing pipe 55 and the second pressure equalizing pipe 55.
Was connected to the sub discharge path 27 via the main discharge path 53 of
The pressure equalizing passage 29a may be directly connected to the sub discharge passage 27. However, in this case, the pressure equalizing passage 29 with respect to the auxiliary discharge passage 27
It is necessary to make the connection position of a on the downstream side of the outlet fixed throttle 28. In addition, the lock state detection sensor 49
Needless to say, does not need to be unique to detect the locked state of the wheel, and can be used, for example, if it is a sensor that detects the movement of the wheel or the brake disc.

[0039]

According to the present invention, there are a main discharge passage side flow passage and a sub discharge passage side flow passage as the brake fluid flow passage from the master cylinder to the wheel cylinder, and the sub discharge side flow passage is always secured. Therefore, even if the spool sticks at a certain position, normal braking and ABS operation can be reliably performed. Further, in the present invention, since a three-way valve is provided in the flow path on the main discharge path side to cut off the flow on the main discharge path side, a pressure difference is generated between the upstream side and the downstream side of the throttle of the sub discharge path. Therefore (to move the spool), it is not necessary to provide two fixed throttles having a small inner diameter in the flow path on the side of the secondary discharge path. Therefore, it is not necessary to create two diaphragms having a delicate balance in inner diameter, and the diaphragm can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a system diagram of an ABS hydraulic unit in normal braking according to a first embodiment of the present invention.

FIG. 2 is a system diagram of the ABS hydraulic unit when the ABS function of the first embodiment according to the present invention is activated.

FIG. 3 is a system diagram of an ABS hydraulic unit when the ABS function of the first embodiment according to the present invention is activated.

FIG. 4 is a simplified ABS of the first embodiment according to the present invention.
It is a system diagram of a hydraulic unit.

FIG. 5 is an embodiment of the ABS hydraulic unit of the second embodiment according to the present invention.

FIG. 6 is a system diagram of a conventional simplified ABS hydraulic unit.

[Explanation of symbols]

1 ... Brake pedal, 2 ... Master cylinder, 3 ... Pump, 4 ... Reservoir, 6 ... Wheel cylinder, 10 ... Flow control valve, 11 ... Spool, 12 ... Annular path, 13 ... First radial path, 14 ... Shaft Directional path, 15 ... Second radial path, 20 ... Casing, 21 ... Spool storage chamber, 22 ...
Spring chamber, 23 ... Back pressure chamber, 24 ... Supply path, 25 ... Inlet fixed throttle, 26 ... Main discharge path, 27, 27a ... Sub discharge path, 2
8, 28a ... Outlet fixed throttle, 29 ... Spring, 29a ... Pressure equalizing passage, 30 ... Three-way solenoid valve, 31 ... First port, 32 ... Second
Port, 33 ... Third port, 40 ... Control unit, 49 ... Lock state detection sensor, 51 ... Supply pipe, 52
... 1st main discharge pipe, 53 ... 2nd main discharge pipe, 54 ... Sub discharge pipe, 55 ... Pressure equalization pipe, 56 ... Circulation pipe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Yamashita 2520 Takaba, Katsuta City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division

Claims (10)

[Claims] 1. A master cylinder that generates a brake fluid pressure in response to an operation of a brake pedal, a wheel cylinder that receives a brake fluid pressure from the master cylinder to apply a braking force to wheels, and a flow rate of the brake fluid is controlled. A flow rate control valve, a reservoir that temporarily stores the brake fluid, three ports, and a three-way valve that switches a flow path depending on whether the wheel is in a locked state, A spool biased to one side is provided in the flow rate control valve so as to be capable of reciprocating in a casing accommodating the spool, and the casing has a supply path for guiding the brake fluid from the master cylinder into the spool. A main discharge passage and a sub discharge passage for discharging the brake fluid therein are formed, and a flow rate of the brake fluid flowing through the sub discharge passage is limited. And a brake fluid pressure in the other space on the opposite side to the one of the two spaces of the casing formed by being partitioned by the spool. A pressure equalizing passage is formed to equalize the brake fluid pressure in a portion of the auxiliary discharge passage on the downstream side of the throttle, and the spool is positioned at the other end of the reciprocating range. When the spool is located at any other position, it is almost impossible to receive the brake fluid from the supply passage inside when receiving the brake fluid from the supply passage. Port, a main discharge port that communicates with the receiving port, and communicates with the main discharge channel when the spool is located at least at the one end of the reciprocating range, and the receiving port. A secondary discharge port that communicates with the auxiliary discharge port and communicates with the auxiliary discharge passage regardless of the position of the spool located in the reciprocating range. A passage is connected to the wheel cylinder, and the main discharge passage of the flow control valve communicates with a second port of the three ports of the three-way valve when the wheel is not locked. A second port of the three-way valve connected to a front wheel cylinder, of the three ports of the three-way valve, the third port communicating with the second port when the wheel is locked. The port is connected to the reservoir, the hydraulic control device for the anti-lock brake device. 2. The antilock brake device according to claim 1, further comprising a pressure buffering means for pressure change of the brake fluid, which is provided between the master cylinder and the receiving port of the spool. Hydraulic control device. 3. The hydraulic control device for an antilock brake system according to claim 1, wherein the throttle provided in the sub discharge path is detachably provided from the casing. 4. The antilock according to claim 1, further comprising a circulation means for guiding the brake fluid stored in the reservoir to an upstream side of the supply passage of the flow rate control valve. Brake system hydraulic control device. 5. A hydraulic control device according to claim 1, 2, 3 or 4, a lock state detecting means for detecting whether or not the wheels are locked, and a lock state detecting means for detecting a lock. ,
When the second port and the third port of the three-way valve are communicated with each other and unlocking is detected, the first port of the three-way valve is detected.
An anti-lock brake device, comprising: a control unit that gives an instruction to the three-way valve so that the port and the second port communicate with each other. 6. A spool, which is biased to one side, is provided reciprocally in a casing that accommodates the spool, and in the casing, a supply path for guiding a liquid therein and a liquid discharge therein. A main discharge passage and a sub discharge passage are formed, and a throttle for limiting the flow rate of the brake fluid flowing therethrough is provided in the sub discharge passage, and the two casings are formed by being partitioned by the spool. A pressure equalizing path for equalizing the hydraulic pressure in the other space of the space opposite to the one side and the hydraulic pressure in the downstream side portion of the throttle of the auxiliary discharge path is formed, and in the spool. When the spool is located at the other end of the reciprocating range, it is almost impossible to receive the liquid from the supply passage, and the spool is located at another position. When said A receiving port capable of receiving the liquid from the passage therein, a communication port with the receiving port, and the main discharge passage when the spool is located at least at the one end of the reciprocating range. A main discharge port that communicates with the reception port, and a sub discharge port that communicates with the sub discharge path regardless of the position of the spool in the reciprocating range are formed. A flow control valve characterized by being 7. The flow rate control valve according to claim 6, wherein the supply passage is provided with a pressure buffering means against a pressure change of the liquid flowing into the casing from here. 8. The flow control valve according to claim 6, wherein the throttle provided in the auxiliary discharge passage is provided so as to be detachable from the casing. 9. A master cylinder for generating a brake fluid pressure in response to an operation of a brake pedal, a wheel cylinder for receiving a brake fluid pressure from the master cylinder to apply a braking force to a wheel, and a lock state of the wheel is detected. Lock state detecting means, a main flow path and a sub-flow path that form a flow path of the brake fluid between the master cylinder and the wheel cylinder, and a brake fluid recovery flow channel that recovers the brake fluid in the wheel cylinder. When the lock state is detected by the lock state detecting means, the main flow path is closed and the brake fluid recovery flow path is opened, and when the lock state is not detected, the main flow path is opened and the brake fluid is opened. A flow path switching means for closing the recovery flow path, and the flow path switching means for closing the main flow path and the brake fluid recovery flow path When opened, the flow passage area on the side of the sub flow passage is gradually reduced, and when the flow passage switching means opens the main flow passage and opens the brake fluid recovery passage, the flow passage area on the side of the sub flow passage is gradually increased. A hydraulic control device for an antilock brake device, comprising: a flow path area adjusting means; 10. The flow passage area adjusting means comprises a fixed throttle provided in the sub flow passage, and a flow passage area on the sub flow passage side in accordance with a pressure difference between an upstream side and a downstream side of the fixed throttle. The hydraulic control device of the antilock brake device according to claim 9, further comprising: