JP3066446B2 - Brake fluid pressure control device - Google Patents

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 for controlling a fluid pressure supplied to a wheel cylinder of each wheel to arbitrarily control a braking force.

[0002]

2. Description of the Related Art Conventionally, as a brake fluid pressure control device,
For example, one described in Japanese Patent Application Laid-Open No. 3-65461 is known.

[0003] In this conventional brake fluid pressure control device, an anti-skid brake system (hereinafter abbreviated as ABS) is provided in a fluid pressure passage between a master cylinder having a booster function and each wheel cylinder provided in a brake device for each wheel. ) And two 2-port 2-position electromagnetic switching valves for a traction control system (hereinafter sometimes abbreviated as TCS). It is a system configuration equipped with.

[0004]

However, such a conventional brake fluid pressure control device is composed of many independent components as described above, so that the weight of the entire system is reduced. In addition to being heavy, a large accommodating space is required as a whole, which causes a problem that vehicle mountability is deteriorated.

The present invention has been made in view of the above-mentioned conventional problems, and provides a brake fluid pressure control device capable of reducing the weight and size of the entire system and improving the mountability on a vehicle. It is intended to be.

[0006]

In order to achieve the above-mentioned object, a brake hydraulic pressure control device according to the present invention comprises a master cylinder for generating a master cylinder pressure based on a brake operation, and a hydraulic pressure higher than the master cylinder pressure. An external hydraulic pressure supply source, a spool for adjusting the control hydraulic pressure by sliding the supply hydraulic pressure from the supply hydraulic pressure from the external hydraulic pressure supply source, and a spool for biasing the control hydraulic pressure in a direction to reduce the control hydraulic pressure. A return spring, a pilot piston that slides in response to the master cylinder pressure and presses the spool in a direction to increase the control fluid pressure, and a slidably provided shaft end of the spool on the end surface side. A reaction piston having an end face abutting against a stopper and receiving control fluid pressure on the other end face side, thereby pushing back the spool in a direction to reduce the control fluid pressure by a reaction pressure receiving pressure, and a plunger. Is provided on the outer periphery of one end of the spool and has a solenoid that has a solenoid that pushes back the spool in a direction to reduce the control hydraulic pressure by the suction force thereof, and brakes each wheel by receiving the control hydraulic pressure. A wheel cylinder, and the pressure receiving area of the pilot piston is formed larger than the pressure receiving area of the reaction force piston by a predetermined magnification.

According to a second aspect of the present invention, the hydraulic pressure control valve has a plunger portion provided on the outer periphery of the other end surface of the spool to increase the control hydraulic pressure by the suction force. And a solenoid that presses the spool.

[0008]

In the brake fluid pressure control device according to the first aspect of the present invention, since the master cylinder pressure is increased during the brake operation, the spool is mounted on the pilot piston which receives the master cylinder pressure. It is arranged at a position where the pressing force and the reaction force of the reaction force piston that receives the control hydraulic pressure plus the set force of the return spring are balanced. In this case, since the pressure receiving cross-sectional area of the pilot piston is larger than that of the reaction force piston, the control hydraulic pressure with respect to the master cylinder pressure is increased by a factor corresponding to the pressure receiving cross-sectional area ratio of both pistons. The wheel cylinder is supplied in a state where the master cylinder pressure is increased at a predetermined magnification, that is, a booster function for boosting the depression force of the brake pedal is exerted, and a strong braking force can be obtained. it can.

In addition, during the ABS control, when a drive current is applied to the solenoid during the brake operation, the suction force of the solenoid pushes the spool back in the direction of reducing the control hydraulic pressure. The resulting braking force is reduced, thereby reducing the amount of wheel slip.

In the brake fluid pressure control device according to the second aspect, when a drive current is applied to the solenoid during the TCS control, the spool presses the spool in a direction in which the suction force of the solenoid increases the control fluid pressure. As a result, the braking force of the wheels is generated by that much even though the brake operation is not performed, and the slip amount of the wheels is reduced.

As described above, since the booster mechanism is compactly incorporated in the hydraulic pressure control valve, the entire system can be reduced in weight and size, and the mountability on the vehicle is enhanced.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. First, the configuration of the embodiment will be described.

FIG. 1 is an overall configuration diagram (including a sectional view taken along line FF of FIG. 2) showing a brake fluid pressure control device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line GG of FIG. Yes,
As shown in both figures, the brake fluid pressure control device of this embodiment includes a master cylinder 2 for generating a master cylinder pressure corresponding to an operation amount of a brake pedal 2a, a wheel cylinder 3 provided in a brake device for each wheel, 3,3,3
And an external hydraulic pressure supply source 6 and a hydraulic control valve 7 for both left and right driving wheels.
a, 7b, hydraulic control valves 8a, 8b for both left and right driven wheels,
It has fail-safe valves 10 a and 10 b and a brake controller 13.

The external hydraulic pressure source 6 includes a hydraulic pump 6a
And a check valve 6b for preventing backflow, an accumulator 6c for storing high-pressure liquid, a pressure switch 6d, and a relief valve 6e provided in the middle of the hydraulic supply fluid passage 14 of the hydraulic pump 6a. ing. A hydraulic damper that eliminates the feeling of stepping on a stone when the brake pedal 2a is operated is provided in the middle of both master cylinder pressure hydraulic paths 15a and 15b output from the master cylinder 2 in two systems for driving wheels and driven wheels. Da and Db are interposed.

In this embodiment, as shown in FIG. 2, the left and right driven wheel hydraulic pressure control valves 7a and 7b, the left and right driven wheel hydraulic pressure control valves 8a and 8b, A valve unit U in which both the fail-safe valves 10a and 10b on the driven wheel side are integrated into the common valve body 1
Are formed.

Next, the specific structure of each valve will be described.

First, the structure of the right driving wheel hydraulic pressure control valve 7b will be described with reference to an enlarged sectional view of FIG. 3. Reference numeral 1 denotes a valve body.
1 is drilled. And in this valve hole 11,
A hydraulic pressure supply port 11a and a drain port 11b are formed, and an output port 11c is formed at a position between both ports 11a and 11b.

As shown in FIGS. 1 and 2, the hydraulic pressure supply port 11a is connected to an external hydraulic pressure connection port 1a formed on an end face of a hydraulic pressure supply body 16 fixed to the upper end of the valve body 1. Hydraulic supply fluid path 1 of external hydraulic supply 6 via
4, the drain port 11b is connected to the drain tank T via the drain side connection port 1b,
It is at atmospheric pressure, and the output port 11c is connected to the wheel cylinder 3 of the right driving wheel via the wheel side connection port 1c.

The valve spool 4 is slidably housed in the valve hole 11. The valve spool 4 has an annular communication groove 4a for communicating between the hydraulic pressure supply port 11a and the output port 11c, and the output port 1
An annular communication groove 4b is formed to allow communication between the drain communication port 1c and the drain port 11b, and the two annular communication grooves 4a, 4b are formed.
A throttle land 4c is formed between the output ports 11c so as to overlap with the output port 11c.
Are formed between the variable apertures s and t.

That is, when the valve spool 4 slides to the left in the drawing, the variable throttle s is narrowed and the variable throttle t is widened, whereby the outflow in the direction of the drain port 11b is reduced from the hydraulic pressure supply port 11a side. Increases, the hydraulic pressure at the output port 11c changes in a direction to increase. On the other hand, when the valve spool 4 slides rightward in the drawing, contrary to the above, the variable throttle s expands and the variable throttle Since t decreases, the amount of outflow toward the drain port 11b becomes larger than the amount of supply from the hydraulic pressure supply port 11a side, so that the control hydraulic pressure at the output port 11c decreases.

At the outer peripheral positions of both left and right ends of the valve spool 4, a solenoid 5a for a TCS (traction control system) that slides the valve spool 4 by a suction force generated by energization, and an ABS (anti-skid brake system) When the TCS solenoid 5a is energized, the valve spool 4 is slid to the left in the drawing to output the output port 11c.
When the ABS solenoid 5b is energized, the valve spool 4 is slid rightward in the drawing to decrease the control hydraulic pressure of the output port 11c.

The solenoids 5a and 5b have solenoid body portions B ₁ and B ₂ , coil portions K ₁ and K ₂ , and plunger portions 54a and 54b.

The solenoid body portions B ₁ and B ₂ are composed of bases 51a and 51b fixed to end faces of the valve body 1 by bolts 60a and 60b, and bases 51a and 51b.
Cylinder 56 made of a nonmagnetic material fitted and fixed to
a, 56b and suction members 58a, 58b fitted to the intermediate cylinders 56a, 56b.

The coil portions K ₁ and K ₂ include coils 53 a and 53 _b for generating a magnetic field, and coils 53 a and 53 _b.
Hobbins 55a, 55b made of non-magnetic material wound with b
And coil casings 52a and 52b that cover the outer periphery of the hobbins 55a and 55b. The coil portions K ₁ and K ₂ are detachably mounted on the outer circumferences of the solenoid body portions B ₁ and B ₂ , and are screwed around the outer circumferences of respective ends of an adjustment member 9 and the suction member 58 b described later. The lock nut 72 and the fastening nut 59 are exchangeably attached to each other.

At the center of the bases 51a and 51b,
Plunger chambers 62a, 62b larger in diameter than valve hole 11
Are formed, and both ends of the valve spool 4 are inserted into the through holes 57a and 57b.
a and 54b are two E-shaped rings 41a and 41, respectively.
It is mounted such that its movement in the axial direction is restricted by b and it can be moved in the radial direction. The plunger portions 54a, 54b are provided in the through holes 57a, 57b.
Bush 100 which comes into contact with the outer periphery of
a, 100b are provided.

The mounting position of the plungers 54a, 54b is set so that a predetermined gap is always maintained between the plungers 54a, 54b and the valve body 1.

The suction members 58a and 58b, the coil casings 52a and 52b, and the bases 51a and 51b
, Bushes 100a, 100b, and plunger portion 54
a and 54b are each formed of a magnetic material, and a magnetic loop is formed by these members. Magnetic leakage portions 61a, 61b having a triangular cross section for generating a force for attracting the plunger portions 54a, 54b are formed on the inner end surfaces of the suction members 58a, 58b. Then, other than the above-mentioned members, in particular, a member (for example, the valve body 1, the valve spool 4, the E-rings 41a, 41b,
The reaction force piston 64, the pilot piston 65, etc.) are made of non-magnetic material such as aluminum (surface anodized), stainless steel, etc., to prevent the adverse effects of the magnetic field and to reduce the magnetic efficiency of the solenoids 5a, 5b. Preventing. As described above, since a predetermined gap is always formed between the valve body 1 and the plunger portions 54a, 54b, if the valve spool 4 side is a non-magnetic material,
Even if the valve body 1 is formed of a magnetic material such as cast iron, no adverse effect is caused. If the valve spool 4 is a non-magnetic material, the reaction force piston 64 can be made of a magnetic material such as steel.

In the through hole 71 of the suction member 58a,
The adjusting member 9 is screwed. And this adjusting member 9
Return spring 4d between the valve spool 4
Are mounted in a compressed state, and the repulsive force presses and biases the valve spool 4 rightward in the drawing. Therefore, in a state where the power is not supplied to both the solenoids 5a and 5b, the valve spool 4 is pressed rightward in the drawing, and the control hydraulic pressure of the output port 11c is in the atmospheric pressure state. The set force of the return spring 4d can be arbitrarily adjusted by changing the screwing amount of the adjusting member 9 into the suction member 58a.

A stopper pin 80 is provided at an axial center portion of the inner end face of the adjusting member 9 so as to protrude toward the end face of the valve spool 4, while an end face of the valve spool 4 opposed to the stopper pin 80 is provided. A piston sliding hole 63 communicating with the output port 11c is formed in the shaft center, and a cylindrical reaction force piston 64 is formed in the piston sliding hole 63.
Are slidably provided.

On the other hand, a pilot chamber 66 into which a cylindrical pilot piston 65 is slidably formed is formed at the axial center of the inner end face of the suction member 58b.
A master cylinder pressure inlet 67 is formed at the outer end face of the master cylinder pressure inlet 8b through an orifice 68 for preventing the pilot piston 65 from damping. The master cylinder pressure inlet 67
Is connected to the master cylinder 2 via a master cylinder pressure fluid passage 15b, as shown in FIG.

A stopper pin 42 whose projection projects into contact with the pilot piston 65 is press-fitted and fixed to the axial center of the end surface of the valve spool 4 which faces the inner end surface of the pilot piston 65.

The drain port 11b is connected to a reservoir tank T via a plunger chamber 62b on the right side of the drawing (see FIG. 1).
Is connected to the plunger chamber 62a on the left side of the drawing via the damping prevention orifice 12.

The left driving wheel hydraulic pressure control valve 7a is
Since the configuration is the same as that of the above-described hydraulic pressure control valve 7b for the right driving wheel, the description thereof is omitted.

Next, the structure of the left driven wheel hydraulic pressure control valve 8a will be described with reference to the enlarged sectional view of FIG.

The driven wheel hydraulic pressure control valve 8a has a configuration in which the solenoid 5a for exerting the TCS function in the above-mentioned right driving wheel hydraulic pressure control valve 7b is omitted, and other components are the same as those described above. Since it is substantially the same as the right-hand drive wheel hydraulic pressure control valve 7b, the same components are denoted by the same reference numerals, and description thereof will be omitted. Only different points will be described.

That is, since the driven wheel hydraulic pressure control valve 8a does not require the plunger portion 54a, the left end of the valve spool 4 is formed to be shorter by that amount. Solenoid body part B ₁ of valve 7
A cylindrical body 90 in which both are integrated is provided instead of the suction member 58 and the adjusting member 9 is screwed to the body 90.

The right driven wheel hydraulic pressure control valve 8b is
Since the configuration is the same as that of the left driven wheel hydraulic pressure control valve 8a described above, the description thereof is omitted.

The hydraulic control valves 7a, 7b, 8
A weak ON-OFF current (dither current) is always applied to each of the solenoids 5a and 5b a and 8b even during normal braking, and the minute vibration of each of the plunger portions 54a and 54b causes the E-shaped ring 41a, The transmission is transmitted to the valve spool 4 via 41b, whereby the valve spool 4 is always vibrated slightly to prevent the occurrence of hysteresis. Note that this weak ON-OFF current (dither current) is shown in FIG.
As shown in (2), the ABS solenoid 5a and the TCS solenoid 5b are applied with their phases shifted by 180 °.

Next, the configuration of the fail-safe valves 10a and 10b will be described with reference to FIG.

The two fail-safe valves 10a, 10b
Are integrated into a hydraulic pressure supply body 16 which is connected and integrated with the upper end face side of the common valve body 1. That is, the hydraulic supply body 16 has the external hydraulic connection port 1a.
In addition, master cylinder pressure connection ports 1d and 1e to which the respective master cylinder pressure liquid passages 15a and 15b are connected are formed (see FIG. 2). The drive wheel side fail-safe valve 10a is provided with a valve seat 17a communicating with the external hydraulic pressure connection port 1a and a valve seat 17b communicating with the master cylinder pressure connection port 1d on opposite end faces. Valve seat 17
a, a cylindrical valve chamber 17c having an opening at one end of the hydraulic pressure supply port 11a, and a valve chamber 17c.
And a ball valve 17d that is operated by the differential pressure and communicates only the higher of the external hydraulic pressure and the master cylinder pressure with the hydraulic pressure supply port 11a.

The valve chamber 17c is formed so as to be slightly inclined in a direction in which the valve seat 17a side communicating with the external hydraulic pressure connection port 1a becomes lower. It falls along the slope by its own weight and is in a state of contacting the valve seat 17a side. Therefore, in this state,
Only the master cylinder pressure is in communication with the hydraulic pressure supply port 11a.

The driven wheel side failsafe valve 10b is
Since it is the same as the drive wheel side fail-safe valve 10a, its description is omitted.

Next, the brake controller 13
As shown in FIG. 1, based on input signals from a vehicle speed sensor 18 and a wheel rotation sensor 19, the TCS solenoid 5a
And an ABS control unit for controlling the driving of the ABS solenoid 5b.

FIG. 5 shows a system diagram of the above-described embodiment, in which a portion surrounded by a dashed line is integrated as a valve unit U.

Next, the operation of the embodiment will be described.

(A) Non-braking When the brake pedal 2a is not depressed, the master cylinder pressure of the master cylinder 2 at each wheel becomes 0. Therefore, each of the hydraulic pressure control valves 7a, 7b, 8a, 8b has a return spring. With the setting force of 4d, the valve spool 4 is pressed and slid to the right as shown in FIG. 3, and the control hydraulic pressure of the output port 11c is O.

Therefore, the hydraulic pressure supplied to each wheel cylinder 3 is also O, and the brake device is inactive.

(B) During normal braking When the brake pedal 2a is depressed, the master cylinder pressure of the master cylinder 2 increases according to the depressing force, and the hydraulic pressure control valves 7a, 7b, 8a, 8b Is received by the pilot piston 65 via the master cylinder pressure inlet 67 and the orifice 68.
5 to press and slide to the left as shown in FIG.
With this pressing force, the valve spool 4 is pressed and slid in the left direction in the drawing against the setting force of the return spring 4d, whereby the control hydraulic pressure of the output port 11c is increased, and the pressure is applied to each wheel cylinder 3. Supply pressure increases.

On the other hand, the control hydraulic pressure of the output port 11c is received by the reaction force piston 64,
Is pressed and slid to the left in the drawing. When the sliding of the reaction force piston 64 is regulated by the stopper pin 80,
The pressure receiving reaction force of the reaction force piston 64 acts on the valve spool 4 as a feedback force, whereby the valve spool 4 is pushed back to the right in the drawing.

That is, the valve spool 4 applies the pressing force of the pilot piston 65 and the pressure receiving reaction force of the reaction force piston 64 +
It is arranged at a position where the set force of the return spring 4d is balanced. In this case, since the pressure receiving cross-sectional area of the pilot piston 65 is larger than that of the reaction piston 64, the control hydraulic pressure (W / W) with respect to the master cylinder pressure (M / CYL pressure) as shown in the boosting function characteristic of FIG. / CYL pressure) is increased by the pressure receiving cross-sectional area ratio of the pistons 65 and 64, whereby the master cylinder pressure for the wheel cylinder 3 is increased to a predetermined magnification (about 9 times in the embodiment).
Is supplied in a state where the pressure is increased, that is, the brake pedal 2
The boosting function (hydraulic pressure booster function) for boosting the pedaling force a is exhibited, and a strong braking force can be obtained.

(C) At the time of ABS operation At the time of sudden braking or at the time of braking on a low μ road such as a snowy road, the frictional resistance of the tire to the road surface becomes smaller than the frictional resistance of the wheel by the braking device, causing the tire to slip. Then, the wheels are locked.

Therefore, AB of the brake controller 13
In the S control unit, when the slip state of the tire is detected from the vehicle speed detected by the vehicle speed sensor 18 and the wheel rotation speed detected by the wheel rotation sensor 19, the hydraulic pressure for the driving wheel is determined according to the slip amount. A drive current is applied to the control valves 7a and 7b and the ABS solenoid 5b of the driven wheel hydraulic pressure control valves 8a and 8b.

As described above, when a current is applied to the ABS solenoid 5b, a magnetic loop is formed by the suction member 58b, the coil casing 52b, the base 51b, the bush 100b, and the plunger portion 54b, and the suction is performed. Attraction force to slide the plunger portion 54b rightward in the drawing is generated in the magnetic leakage portion 61b having a triangular cross section formed on the inner end surface of the member 58b, and this suction force is applied to the valve spool 4 via the E-shaped ring 41b. It is transmitted and acts in a direction to push back the valve spool 4 rightward in the drawing.

That is, the pressing force of the pilot piston 65 generated by the brake operation, the pressure receiving reaction force of the reaction force piston 64, the set force of the return spring 4d, and the suction force.
The valve spool 4 is disposed at a position where the pressure is balanced, that is, the valve spool 4 is pushed back to the right in the drawing by the suction force, whereby the control hydraulic pressure (supply hydraulic pressure to the wheel cylinder 3) decreases. As the braking force of the wheel decreases, the slip amount of the wheel decreases.

Then, AB of the brake controller 13
In the S control unit, the detected slip amount is constantly compared with a preset appropriate slip amount (braking force), and the current applied to the ABS solenoid 5b is adjusted so that the detected slip amount becomes an appropriate slip amount. Is controlled. That is, within the range of the ABS function shown in FIG. 6, the control hydraulic pressure (W / CY) with respect to the master cylinder pressure (M / CYL pressure).
L pressure) characteristics can be changed.

(D) TCS operation When the vehicle suddenly starts or accelerates, the accelerator torque depresses, and the engine torque sharply increases. This engine torque overcomes the frictional force of the wheels against the road surface.
A tire slip phenomenon occurs. That is, the rotation speed of the wheels becomes higher than the vehicle speed, and if left unattended, the steering becomes unstable.

Therefore, the TC of the brake controller 13
In the S control unit, when the slip state of the tire is detected from the vehicle speed detected by the vehicle speed sensor 18 and the wheel rotation speed detected by the wheel rotation sensor 19, the hydraulic pressure for the driving wheel is determined according to the slip amount. A drive current is applied to the TCS solenoid 5a of the control valves 7a, 7b.

As described above, when a current is applied to the TCS solenoid 5a, a magnetic loop is formed by the attracting member 58a, the coil casing 52a, the base 51a, the bush 100a, and the plunger portion 54a. Attraction force to slide the plunger portion 54a to the left in the drawing is generated in the magnetic leakage portion 61a having a triangular cross section formed on the inner end surface of the member 58a, and this suction force is applied to the valve spool 4 via the E-shaped ring 41a. The valve spool 4 is pressed and slid in the left direction in the drawing, whereby
By increasing the control hydraulic pressure of the output port 11c, the supply hydraulic pressure to the wheel cylinder 3 increases.

On the other hand, the control hydraulic pressure of the output port 11c is received by the reaction force piston 64,
Is pressed and slid to the left in the drawing. When the sliding of the reaction force piston 64 is regulated by the stopper pin 80,
The pressure receiving reaction force of the reaction force piston 64 acts on the valve spool 4 as a feedback force, whereby the valve spool 4 is pushed back to the right in the drawing.

That is, the valve spool 4 is arranged at a position where the suction force by the TCS solenoid 5a and the pressure receiving reaction force of the reaction force piston 64 + the set force of the return spring 4d are balanced. The spool 4 is pressed and slid to the left in the drawing.
Despite the absence of the brake operation, the control fluid pressure (supply fluid pressure to the wheel cylinder 3) increases to generate a braking force on the wheels, thereby reducing the slip amount of the wheels.

The TC of the brake controller 13
In the S control unit, the detected slip amount is constantly compared with a preset appropriate slip amount (driving force), and the applied current value to the TCS solenoid 5a is adjusted so that the detected slip amount becomes an appropriate slip amount. Is controlled. That is, the control hydraulic pressure (W / CYL pressure) can be generated within the range of the TCS function shown in FIG.

(E) Fail-safe operation If the hydraulic pressure on the hydraulic supply line 14 decreases due to a failure on the hydraulic pump 6a side, there is no hydraulic pressure difference. Ball valve 1 for 10a and 10b
7d falls along its inclination by its own weight, and is in contact with the valve seat 17a side to close the external hydraulic pressure connection port 1a side, and only the master cylinder pressure communicates with the hydraulic pressure supply port 11a side. It is in a state.

When the brake pedal 2a is depressed in this state, the master cylinder pressure of the master cylinder 2 increases in accordance with the depression force, and this master cylinder pressure is increased by the hydraulic pressure control valves 7a, 7b, 8a, 8b. At the same time as being supplied to the master cylinder pressure connection port 1d, the fail-safe valve 10
a, 10b from the master cylinder pressure connection port 1d to the valve seat 1
The fluid is also supplied to each hydraulic pressure supply port 11a via the valve chamber 7b and the valve chamber 17c.

Therefore, as shown in the guaranteed hydraulic pressure characteristic of FIG. 6, the boosting function is eliminated, but even if the external supply hydraulic pressure becomes zero, the braking force of the brake device on each wheel can be secured.

As described above, the following effects can be obtained in this embodiment.

Each hydraulic pressure control valve 7a, 7b, 8a, 8b
The hydraulic booster mechanism that exhibits the boosting function is compactly incorporated therein, and the hydraulic pressure control valves 7a, 7b,
8A and 8B and both fail-safe valves 10a and 10b are all integrated into the common valve body 1, so that the entire system can be reduced in weight and size, and the mountability on the vehicle is improved.

The plungers 54 a, 54 b of the solenoids 5 a, 5 b are provided integrally with the valve spool 4 in a state where movement in the axial direction is restricted, and the solenoid 5
a, 5b, weak ON-OFF even during normal braking
By applying a current (dither current), the valve spool 4 can be finely vibrated.
As shown by the dotted line in FIG. 8, it is possible to prevent the occurrence of hysteresis of the control hydraulic pressure based on the sliding resistance and improve the operability of the brake.

[0068] Valve spool 4, reaction force piston 64
And the pilot piston 65 is formed in a straight cylindrical shape without a step, and these are arranged at the center of the solenoids 5a and 5b, so that the solenoid 5
a, 5b can be compactly arranged at the center of the solenoids 5a, 5b without lowering the drive efficiency of the hydraulic pressure control valves 7a, 5b without being affected by magnetism. 7b, 8a and 8b can be further reduced in weight and size. In addition, since the hydraulic sealing property of the sliding portion can be improved, the control hydraulic pressure can be set higher.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Included in the invention.

[0070]

As described above, in the brake fluid pressure control device according to the present invention, the pilot piston which presses the spool in the direction of increasing the control fluid pressure by sliding by receiving the master cylinder pressure. The pressure receiving area is made larger by a predetermined magnification than the pressure receiving area of the reaction force piston that pushes the spool back in the direction of reducing the control hydraulic pressure by the pressure receiving reaction force of the control hydraulic pressure, so that the master in the hydraulic pressure control valve is The hydraulic pressure booster mechanism for boosting the cylinder pressure is compactly assembled, and as a result, the system as a whole can be reduced in weight and size, and the effect of improving the mountability in a vehicle can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line GG of FIG.

FIG. 3 is an enlarged cross-sectional view showing a configuration of a right driving wheel hydraulic pressure control valve.

FIG. 4 is an enlarged sectional view showing a configuration of a left driven wheel hydraulic pressure control valve.

FIG. 5 is a system diagram showing a brake fluid pressure control device according to an embodiment of the present invention.

FIG. 6 is a hydraulic pressure characteristic diagram of the hydraulic pressure control valve.

FIG. 7 is a diagram showing a dither current waveform for a solenoid.

FIG. 8 is a hydraulic pressure characteristic diagram obtained by applying a dither current.

[Explanation of symbols]

 2 Master cylinder 3 Wheel cylinder 4 Valve spool 4d Return spring 5a Solenoid for TCS 5b Solenoid for ABS 6 External hydraulic pressure supply source 7a Hydraulic control valve for left driving wheel 7b Hydraulic control valve for right driving wheel 8a Liquid for left driven wheel Pressure control valve 8b Hydraulic pressure control valve for right driven wheel 54a Plunger portion 54b Plunger portion 64 Reaction piston 65 Pilot piston 80 Stopper pin

Claims (2)

(57) [Claims] 1. A master cylinder for generating a master cylinder pressure based on a brake operation, an external hydraulic pressure source for supplying a hydraulic pressure higher than the master cylinder pressure, and a supply hydraulic pressure from the external hydraulic pressure source As a source, a spool that regulates the control fluid pressure by sliding, a return spring that urges the spool in a direction to reduce the control fluid pressure, and a direction that increases the control fluid pressure by sliding by receiving the master cylinder pressure. A pilot piston that presses the spool, and a slidably mounted shaft at the end face side of the spool.The protruding end face abuts against the stopper and receives the control hydraulic pressure on the other end face. A reaction force piston that pushes the spool back in the direction of reducing the control hydraulic pressure, and a plunger portion provided on the outer periphery of one end of the spool to reduce the control hydraulic pressure by its suction force A hydraulic pressure control valve having a solenoid that pushes a spool back to the spool, and a wheel cylinder that receives control hydraulic pressure to brake each wheel, wherein a pressure receiving area of the pilot piston is determined from a pressure receiving area of a reaction force piston. A brake fluid pressure control device characterized in that the brake fluid pressure control device is formed to have a large magnification. 2. The hydraulic pressure control valve, wherein a plunger portion is provided on the outer periphery of the other end surface of the spool, and a solenoid is provided for pressing the spool in a direction to increase the control hydraulic pressure by its suction force. The brake fluid pressure control device according to claim 1, wherein: