JPH11180289A - Hydraulic braking device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic braking device that can boost-drive a master cylinder with output fluid pressure of a pressure regulating valve means without impairing an operating feeling of a brake operating member and can drive the master cylinder directly by the operation of the brake operating member. SOLUTION: Output brake fluid pressure of an auxiliary fluid pressure source 40 is supplied to a pressure regulating valve means in response to the operation of a brake pedal 2 so as to be regulated to specified pressure and imparted to a power chamber R1 to assist driving of the brake pedal 2. A master cylinder piston is provided with a first piston 11 connected to the brake pedal 2, and a second piston 12 relatively slidable to the first piston 11 and engaged with the first piston 11 at the time of moving forward. The first and second pistons 11, 12 are so arranged that the respective rear end parts are exposed to the power chamber R1 and that the front end parts are exposed to a pressure chamber R2. A check valve 60 allowing the flow of a brake fluid from the auxiliary fluid pressure source to the pressure regulating valve means while impeding reverse direction flow is interposed in a fluid pressure passage for supplying the output power fluid pressure of the auxiliary fluid pressure source to the pressure regulating valve means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake device for supplying a brake hydraulic pressure to a wheel cylinder of a vehicle wheel, and more particularly to a hydraulic brake device provided with an auxiliary hydraulic pressure source and pressure regulating valve means in addition to a master cylinder. The present invention relates to a hydraulic brake device.

[0002]

2. Description of the Related Art Various types of hydraulic brake devices for automobiles are known.
Japanese Patent No. 24819 discloses a vehicle brake control device including an auxiliary hydraulic pressure source (described as a pressure source in the same publication) and a pressure regulating valve means (regulator) in addition to a master cylinder. In this device, a pressure chamber is formed in front of a master cylinder piston (first piston) and a power chamber (auxiliary pressure chamber) is formed behind the master cylinder piston. A master cylinder for outputting brake fluid pressure from the chamber is provided. Also, an auxiliary hydraulic pressure source (pressure source) that boosts the brake fluid to a predetermined pressure and outputs power hydraulic pressure, and a master cylinder piston that is slidably housed in front of the master cylinder piston in the cylinder body in a liquid-tight manner. A control piston (second piston) disposed so as to interlock with the control piston, and pressure regulating valve means (spool member) for regulating the output power hydraulic pressure of the auxiliary hydraulic pressure source to a predetermined pressure according to the movement of the control piston, The brake fluid pressure regulated by the pressure regulating valve means is applied to the power chamber of the master cylinder to boost the operating force of the brake operating member. An orifice is provided between the regulator pressure chamber and the regulator port to increase the boosting ratio in accordance with the operation speed of the brake operation member, thereby increasing the braking force at the time of emergency braking.

On the other hand, JP-A-2-41965 discloses that
If the output hydraulic pressure of the power hydraulic pressure source or hydraulic booster as the auxiliary hydraulic pressure source is insufficient, activate the pressure booster to increase the output brake hydraulic pressure of the master cylinder,
When the output hydraulic pressure of a power hydraulic pressure source or a hydraulic booster is sufficient and no boosting action is required, a hydraulic brake device is disclosed in which a booster is deactivated to prevent excessive brake hydraulic pressure from being generated. I have. This hydraulic brake device is an intensifier that increases the brake fluid pressure when one of a power fluid pressure and an output fluid pressure of a fluid pressure booster falls below a brake fluid pressure of a master cylinder by more than a predetermined pressure difference. And a control device for inputting any one of the output hydraulic pressures of the power hydraulic pressure source, the hydraulic booster, and the master cylinder, and setting the booster to an operating state only when the output hydraulic pressure is equal to or lower than a predetermined pressure. Things.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 2-419 is disclosed.
In the hydraulic brake device described in Japanese Patent Publication No. 65, the master cylinder and the hydraulic booster are integrally formed, but the pressure intensifiers are separately provided side by side, so that the hydraulic brake device becomes large and the configuration of the hydraulic pressure path becomes complicated. Difficult to design. In contrast,
In the brake device described in the above-mentioned Japanese Patent Application Laid-Open No. 9-24819, for example, a master cylinder piston is constituted by two pistons, and each front end and rear end are arranged so as to be exposed to a pressure chamber and a power chamber, respectively. If the output hydraulic pressure of the auxiliary hydraulic pressure source is sufficient, the master cylinder is boosted by the output hydraulic pressure of the pressure regulating valve means according to the operation of the brake operating member, and the output hydraulic pressure of the auxiliary hydraulic pressure source is not sufficient. When sufficient, one piston can be directly driven in response to the operation of the brake operation member to output the brake fluid pressure.

However, if the master cylinder piston is composed of two pistons as described above, for example, even after the hydraulic pressure control by the auxiliary hydraulic pressure source is completed, the brake operating member continues to be operated with a large force, and the hydraulic pressure in the pressure chamber becomes lower. When the pressure becomes higher than the hydraulic pressure in the room by a predetermined pressure or more, the other piston not directly connected to the brake operating member retreats, and the one piston connected to the brake operating member advances. As a result, the brake operating member moves forward rapidly, giving the driver an uncomfortable feeling. This is because the brake fluid in the power chamber flows back to the uncontrolled auxiliary hydraulic pressure source, so if it is possible to prevent the brake fluid from flowing back from the power chamber to the auxiliary hydraulic pressure source, the brake operating member A rapid advance can be effectively prevented.

Accordingly, the present invention provides a hydraulic brake system for a vehicle having an auxiliary hydraulic pressure source and a pressure regulating valve means in addition to a master cylinder, without impairing the operation feeling of the brake operating member, without damaging the output fluid of the pressure regulating valve means. It is an object of the present invention to provide a hydraulic brake device that can drive a master cylinder by pressure and drive a master cylinder directly by operating a brake operation member.

[0007]

According to the present invention, a master cylinder piston is accommodated in a cylinder body so as to be slidable in a liquid-tight manner, and a pressure chamber is formed in front of the master cylinder piston. A power chamber is formed at the rear and a master cylinder that drives the master cylinder piston forward and outputs brake fluid pressure from the pressure chamber according to the operation of the brake operating member, and boosts the brake fluid to a predetermined pressure. An auxiliary hydraulic pressure source that outputs power hydraulic pressure, a control piston that is slidably housed in front of the master cylinder piston in the cylinder body and is disposed so as to interlock with the master cylinder piston, Pressure regulating valve means for regulating the output power hydraulic pressure of the hydraulic pressure source to a predetermined pressure according to the movement of the control piston, wherein the pressure regulating valve means adjusts the pressure. In a hydraulic brake device for a vehicle that applies brake fluid pressure to a power chamber of the master cylinder to assist in driving the brake operation member, the master cylinder piston includes a first piston connected to the brake operation member; A second piston slidably disposed relative to the first piston and engaged with the first piston during forward movement, wherein a rear end of each of the first and second pistons is While being exposed to the power chamber, each front end is arranged so as to be exposed to the pressure chamber, and a hydraulic pressure path for supplying the output power hydraulic pressure of the auxiliary hydraulic pressure source to the pressure regulating valve means,
A check valve that allows the flow of the brake fluid from the auxiliary hydraulic pressure source to the pressure regulating valve means and prevents the flow in the reverse direction is interposed. Accordingly, the second piston advances only by the pressure of the power chamber, and the first piston advances by the operating force of the brake operating member and the pressure of the power chamber.

In the hydraulic brake device for a vehicle, a pressure detecting device detects an output power hydraulic pressure of the auxiliary hydraulic pressure source in a hydraulic pressure passage for supplying an output power hydraulic pressure of the auxiliary hydraulic pressure source to the pressure regulating valve means. Preferably, the check valve is connected, and the check valve is interposed between the connection portion of the pressure detecting means and the pressure regulating valve means.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a brake fluid pressure control device according to an embodiment of the present invention, in which a master cylinder portion and a regulator portion are formed in a cylinder body 1h, and a vehicle rear side (right side in FIG. 1). Is provided with a brake pedal 2 as a brake operating member. The pedaling force applied to the brake pedal 2 is transmitted as a brake operating force via the push rod 3, and in response to this, the output brake fluid pressure of the master cylinder unit and the regulator unit changes the front right and left wheels FR, FL, FL, And wheel cylinders Wf of the rear right and left wheels RR and RL.
r, Wfl, Wrr, and Wrl (FIG. 1 shows only the wheels FR, RR on the front and rear right of the vehicle, and the wheel cylinders Wfr, Wrr mounted on each wheel).

In the cylinder body 1h, there are formed stepped holes made up of holes 1a, 1b, 1c and the like having different inner diameters.
The master cylinder piston 10 including the first and second pistons 11 and 12 and the control piston 21 are accommodated therein, and a pressure chamber R2 is defined between the first piston 11 and the control piston 21. The hole 1a communicates with a power chamber R1 having a larger inner diameter. A control piston 21 is slidably fitted in the small-diameter hole 1c in a liquid-tight manner. The master cylinder piston 10 is accommodated in both the hole 1b having a diameter larger than the hole 1c and the hole 1a having a diameter larger than the hole 1c, and is fitted slidably in a liquid-tight manner.

The master cylinder piston 10 comprises a first piston 11 and a second piston 12, and the first piston 11 is further divided into a piston 11x and a piston 11y. The second piston 12 is a cylindrical body, and has a land portion 12e formed on the inner surface of the hollow portion, and a seal member 12f is provided on the land portion 12e. A large-diameter land portion 12a is formed on the outer surface of the second piston 12, and a small-diameter land portion 12b is formed at a predetermined distance in the axial direction. A seal member 12c is disposed on the land portion 12a. The hole 1a is slidably fitted in a liquid-tight manner, the land 12b is provided with a seal member 12d, and the hole 1b is slidably fitted in a liquid-tight manner. A communication hole 12g is formed on the rear side of the land 12e. Land portion 12 in hole 1b
The liquid supply chamber R5 defined between a and 12b is connected to the reservoir 4 through a port 1e.

The piston 1 constituting the first piston 11
1x is accommodated in the hollow portion of the second piston 12, and is supported by the land portion 12e. In the axial direction of the piston 11x, an axial hole 11c communicating with the pressure chamber R2 is formed, and the hole 11c communicates with a gap between the outer surface of the piston 11x and the inner surface of the second piston 12. A direction hole 11d is formed. Also, piston 11x
A cylindrical support portion 11s is integrally formed so as to surround the front opening of the hole 11c, and the valve body 25 is accommodated therein. The retainer 16 is provided on the support portion 11s.
Is mounted, and a spring 19 is stretched over the retainer 16 to urge the piston 11x and the control piston 21 to expand. The gap between the outer surface of the piston 11x and the inner surface of the second piston 12 communicates with the liquid supply chamber R5 via the communication hole 12g. Therefore, when the valve body 25 opens as described later, the pressure chamber R2 is in the hole 11.
It communicates with the liquid supply chamber R5 via c and 11d and the communication hole 12g. In this embodiment, no seal member is provided on the piston 11x side.

Further, a piston 11y is accommodated on the rear side inside the second piston 12. A land 11e and a shoulder 11f are provided at the front end of the piston 11y, and a cup-shaped seal member 14 is interposed between the land 11e and the shoulder 11f. Are slidably fitted in a liquid-tight manner, and the piston 11y
Are arranged so that the front end surface of the piston 11x contacts the rear end surface of the piston 11x. When the first piston 11 and the second piston 12 move in a direction in which the first piston 11 and the second piston 12 are relatively separated from each other, the flow of the brake fluid from the reservoir 4 to the closed space R6 (the port 1e, the communication hole 12g and the piston 11
(via x holes 11c, 11d). The main body of the piston 11y is a cylindrical sleeve 17
Supported by An annular groove is formed on the inner surface and the outer surface of the sleeve 17, and an annular groove is also formed on the inner surface separated from the inner surface by a predetermined distance in the axial direction. These grooves accommodate a seal member 17a, a cup-shaped seal member 17b, and a seal member 18, respectively, to ensure sealing performance with respect to the power chamber R1.

An annular holding member 13 is fixed to the rear end of the second piston 12, and a groove 13 is formed in the inner end surface thereof.
The seal member 13b is housed in the groove 13a. The shoulder 11f of the piston 11y is locked to the holding member 13. Also,
The holding member 13 has an aperture 13g. Thus, a closed space R6 is formed between the seal member 14 of the piston 11y and the seal member 13b of the holding member 13,
The closed space R6 communicates with the power chamber R1 via the throttle 13g, and can communicate with the power chamber R1 via a gap between the spherical valve element 52 and the valve seat 13f.

That is, a hole 13d is formed in the holding member 13 in the axial direction, and the plunger 51 is supported in the hole 13d. Further, a hole 13e is formed in a radial direction of the holding member 13, and communicates with the power chamber R1. Holding member 1
A valve seat 13f is formed at the front open end of the third hole 13d, and in the state shown in FIGS. 1 and 2 in which the second piston 12 and the holding member 13 are located at the rear end, the plunger 51 is connected to the valve seat 1
It is arranged so as to project slightly forward from 3f. Thus, the valve body 52 is held in a state where it is slightly separated from the valve seat 13f. Therefore, when the second piston 12 and the holding member 13 are located at the rear end, the power chamber R
1 and the closed space R6 are provided with a throttle 13g, a valve body 52 and a valve seat 13f.
With a sufficient flow path area through the gap between
When the valve body 52 is seated on the valve seat 13f, the valve body 52 communicates only through the throttle 13g, so that the flow passage area is limited.

Next, a regulator section having a spool valve mechanism is formed in a front portion of the cylinder body 1h, and an auxiliary hydraulic pressure source 40 is connected to the regulator section, and its output power hydraulic pressure is appropriately controlled. Is output. Auxiliary hydraulic pressure source 40
Has a hydraulic pump 43 driven by an electric motor 42, the input side is connected to the reservoir 4, the output side is connected to the accumulator 44, and the power hydraulic pressure is supplied from the accumulator 44 to the communication hole 31d via the hydraulic path 1p. It is configured to be.

A hydraulic pressure path between the accumulator 44 of the auxiliary hydraulic pressure source 40 and the hydraulic pressure path 1p of the regulator section is provided with a pair of hydraulic pressure detecting means for detecting the output power hydraulic pressure of the auxiliary hydraulic pressure source 40. The pressure sensors PH and PL are connected, and a check valve 60 is interposed in a hydraulic path between the hydraulic sensors PH and PL and the hydraulic path 1p of the regulator section. The hydraulic pressure sensors PH and PL detect the output state of the auxiliary hydraulic pressure source 40.
Is set to detect a state on the low pressure side, and is generally constituted by a switch. Check valve 60 is valve element 6
1 and a spring 62 for urging the valve in a direction to close the valve, so as to allow the flow of the brake fluid in the direction of the hydraulic pressure path 1p of the regulator section and to prevent the flow in the direction of the auxiliary hydraulic pressure source 40. Are located.

The control piston 21 housed in the hole 1c is provided with a pair of land portions 21a, 21a at a predetermined distance in the axial direction.
21b, an annular seal member 24 is attached only to the front land portion 21a, and the rear land portion 2
1b is in communication. Therefore, the pressure chamber R2 and a regulator chamber R3 described later are separated by the seal member 24, and the seal member 24 and the land portion 1 of the piston 11 are separated.
A pressure chamber R2 is formed between the pressure chamber R2 and the seal member 14 mounted on the pressure chamber 1e.

As is apparent from FIG. 1, the control piston 21 is formed with a through hole 21c penetrating in the radial direction and extending in the axial direction and opening at the rear end. Land part 2 in front
1a is a locking pin 2 which is located at the rear end and extends radially.
8 is fixed to the cylinder body 1h, which allows the control piston 21 to move forward, but restricts retreat (movement in the direction of the master piston 10). A cylindrical support portion 21 surrounding the rear end of the control piston 21
s is integrally formed to extend therethrough and accommodates a locking portion 25c connected to the valve body 25 via a shaft 25b. A retainer 26 is attached to the support portion 21s, and a retaining portion 25c is retained by the retainer 26, thereby restricting the movement of the valve body 25 in the direction of the master piston 10. A recess is formed at the front end of the control piston 21, and a rear end of a spool 32 described later is held in the recess.

A cylindrical sleeve 31 and an adjusting member 36 are fitted in a stepped hole 1c communicating with the hole 1b, and a regulator chamber R3 serving as a pressure adjusting chamber is provided between the sleeve 31 and the control piston 21. Are formed. Sleeve 31
A plurality of annular grooves are formed on the outer periphery of the adjusting member 36, and annular seal members are fitted to the respective annular grooves. Between these adjacent seal members, communication holes 31d and 31f are formed in the radial direction of the sleeve 31, and a stepped portion 36b is formed in the sleeve-shaped adjusting member 36, and the communication holes 3d are formed in the radial direction.
6c (shown up and down in FIG. 1).
A spool 32 is slidably accommodated in the hollow portion of the sleeve 31, and is disposed so that the opening of the communication hole 31 f is blocked by the forward movement of the spool 32.

In the axial direction of the sleeve 31, there is formed a communication hole 31e having one end communicating with the communication hole 31f and the other end communicating with the regulator chamber R3. When the communication hole 31f is open, the regulator chamber R3 is opened. Are communicating holes 31e, 3
It is configured to be able to communicate with the hydraulic path 1s via 1f. The communication hole 31d is connected to the auxiliary hydraulic pressure source 40 through the hydraulic pressure path 1p, but is shielded by the outer peripheral surface of the spool 32 at the position shown in FIG. Furthermore, the communication hole 3
An annular groove 31c is formed in the inner peripheral surface of the sleeve 31 behind 1d. The communication holes 36c are respectively connected to the hydraulic passages 1q and 1q.
1r.

A plunger 35 is fitted to the front end of the spool 32 so as to protrude in the axial direction.
The rear end is located in the regulator chamber R3 and is locked to the control piston 21. That is, the retainer 33 is supported in the concave portion in front of the control piston 21,
A spring 34 is stretched between the control piston 21 and the spool 32 and the spool 32 is urged to abut the control piston 21. At the initial position (retracted position) of the control piston 21, the opening of the communication hole 31f is not shielded by the spool 32, and the regulator chamber R3 is connected to the communication holes 31e and 31f of the sleeve 31 and the hydraulic pressure path 1s. And is filled with brake fluid at atmospheric pressure.
In the outer peripheral surface of the spool 32, an annular groove 32b is formed at a retreat position over a predetermined range in the axial direction centered on the rear end of the sleeve 31, and a predetermined distance is provided in front of the annular groove 32b. An annular groove 32c is formed at a position facing the groove 31c.

At the position shown in FIG. 1, the inside of the regulator chamber R3 communicates with the reservoir 4 through the communication holes 31e and 31f of the sleeve 31 and the hydraulic path 1s, and the pressure in the regulator chamber R3 is atmospheric. When the spool 32 moves forward with the forward movement of the control piston 21, the communication hole 31f of the sleeve 31 is shut off, and instead the communication hole 31d faces the groove 32c of the spool 32, and the groove 31c and the groove 32b
Oppose each other and thus communicate with the auxiliary hydraulic pressure source 40. As a result, the power hydraulic pressure of the auxiliary hydraulic pressure source 40 becomes
It is supplied to the inside and is boosted.

On the other hand, the hollow portion of the adjusting member 36 is formed in a stepped hole shape, and the transmission member 37 is slidably accommodated in the small-diameter hole portion in the axial direction, and the rear end surface thereof faces the front end surface of the plunger 35. Are arranged as follows. Further, an elastic member 38 made of, for example, rubber is fitted in the large-diameter hole portion of the adjusting member 36, and the transmission member 37 is arranged so that the front end surface thereof is in contact with the elastic member 38. A plug 39 is fitted to the front end of the hollow portion of the adjusting member 36, a pressure transmission chamber R4 is formed between the plug 39 and the elastic member 38, and the hydraulic pressure path 1 is formed.
It is connected to the regulator chamber R3 through q.
Thus, the regulator hydraulic pressure adjusted according to the relative movement of the spool 31 with respect to the sleeve 32 is applied to the pressure transmission chamber R.
When the spool 32 is introduced into the elastic member 38 and applied to the elastic member 38, the spool 32 is pushed rearward via the transmission member 37, and the regulator hydraulic pressure in the regulator chamber R3 is reduced. In the present embodiment, a frusto-conical abutment member (reference numeral omitted) is provided at the front end of the transmission member 37, but the front end of the transmission member 37 may be formed in the same shape.

The pressure transmission chamber R4 is connected to the regulator chamber R3 via the communication hole 36c and the hydraulic passage 1q, and is connected to the power chamber R1 via the communication hole 36c and the hydraulic passage 1r.
Is connected to the Further, the pressure chamber R2 is provided with a hydraulic passage 1n.
The power chamber R1 is connected to the wheel cylinder Wrr via the hydraulic passage 1k.

Next, the overall operation of the hydraulic brake device having the above configuration will be described. FIG. 1 shows a state where the brake pedal 2 is not operated. From this state, when the brake pedal 2 is operated and the push rod 3 and the piston 11 are pressed forward (to the left in FIG. 1), the piston 11x is in contact with the valve 25, and the elastic member of the valve 25
1c is closed, the communication between the pressure chamber R2 and the liquid supply chamber R5 is cut off, and a closed state is established. When the piston 11 is driven by the operating force of the brake pedal 2 in a state where the communication between the pressure chamber R2 and the liquid supply chamber R5 is interrupted, the piston 11 and the control piston 21 are moved via the spring 19 as shown in FIG. Since they are held in the state 1, they move forward together.

Accordingly, the communication hole 31f is closed by the spool 32 supported by the control piston 21, and the communication with the reservoir 4 is cut off. At the same time, the power hydraulic pressure from the auxiliary hydraulic pressure source 40 is transmitted from the hydraulic pressure path 1p via the check valve 60 to the communication hole 31d, the annular grooves 31c, 32c, and the groove 32b.
, Flows into the regulator chamber R3, is supplied as a regulator hydraulic pressure to the pressure transmission chamber R4 via the hydraulic passage 1q, and is further supplied to the power chamber R1 via the hydraulic passage 1r. As a result, the pistons 11 and 12 are assisted to move forward, the pressure chamber R2 is further compressed, the master cylinder hydraulic pressure is output to the wheel cylinder Wfr via the hydraulic pressure passage 1n, and the regulator hydraulic pressure is also reduced to the power chamber. R1 is output to the wheel cylinder Wrr via the hydraulic path 1k.

During this time, the force applied to the control piston 21 by the regulator fluid pressure in the regulator chamber R3 is:
If the force applied to the control piston 21 by the master cylinder fluid pressure in the pressure chamber R2 is larger than the control piston 2
1 moves rearward, the communication hole 31f opens and communicates with the reservoir 4, so that the pressure in the regulator chamber R3 is reduced. When the relationship of the force applied to the control piston 21 is reversed, the control piston 21 moves forward, the communication hole 31f is shut off, and the regulator chamber R3 is replaced with the communication hole 31d.
Thus, the pressure in the regulator chamber R3 is increased. Such a control piston 21
By repeating the movement of the spool 32 accompanying the movement of
Control is performed so that the force by the regulator hydraulic pressure applied to the control piston 21 and the force by the master cylinder hydraulic pressure are equal. Until the force due to the regulator hydraulic pressure in the pressure transmission chamber R4 is transmitted to the plunger 35 via the elastic member 38 and the transmission member 37, a regulator hydraulic pressure that is substantially proportional to the master cylinder hydraulic pressure is output.

Further, the regulator fluid pressure is increased, and the central portion of the elastic member 38 is displaced rearward by the regulator fluid pressure supplied to the pressure transmission chamber R4, so that the transmission member 37 comes into contact with the plunger 35 and the spool 32 is moved rearward. , The opening area of the communication hole 31f increases. This allows
The regulator fluid pressure in the regulator chamber R3 is reduced,
A brake fluid pressure characteristic that is substantially proportional to the master cylinder fluid pressure but has a pressure increasing gradient that is gentler than that of the brake fluid pressure characteristic is obtained.

With respect to the operation of the master cylinder piston 10, the piston 11 is operated in accordance with the operation of the brake pedal 2.
When the x and the piston 11y move forward and move in the direction of the control piston 21, the shoulder 11f of the piston 11y
3, the closed space R6 expands. At this time, a part of the brake fluid flows into the closed space R6 from the port 1e via the one-way-permissible seal member 14. In this state, when the regulator hydraulic pressure is supplied to the power chamber R1, the second piston 12 and the holding member 13 move forward, and the valve body 52 is urged to be seated on the valve seat 13f. Therefore, the power chamber R1 and the closed space R6 communicate with each other only through the throttle 13g, and the flow path area is limited. As a result, the brake fluid in the closed space R6 is gently discharged to the power chamber R1 via the throttle 13g, so that the shock when the holding member 13 contacts the piston 11y due to the damper effect is reduced.

On the other hand, when the regulator hydraulic pressure does not exist in the power chamber R1, when the brake pedal 2 is suddenly operated, the pistons 11x and 11y reach the front end, but the second piston 12 remains. , The capacity of the closed space R6 increases. When the brake pedal 2 is released in this state, the pistons 11x and 11y move in a direction to reduce the volume of the closed space R6, but the second piston 12 and the holding member 13 are in contact with the sleeve 17 ( Valve 5
2 and the valve seat 13f are secured). As a result, the power chamber R1 and the closed space R6 communicate with each other between the valve body 52 and the valve seat 13f through the hole 13e and the throttle 13g, thereby ensuring a sufficient flow passage area, and returning the pistons 11x and 11y. Thus, the return operation of the brake pedal 2 is performed smoothly.

FIG. 4 shows the relationship between the pedaling force applied to the brake pedal 2 and the wheel cylinder hydraulic pressure in the above-described embodiment. The solid line shows the normal characteristics, and the broken line shows the characteristics when the power hydraulic pressure disappears. The two-dot chain line shows the characteristics in the case where the second piston 12 is not provided. Since the cross-sectional area of the piston is relatively large, the wheel cylinder hydraulic pressure (ie, the pressure chamber R2 Pressure). On the other hand, in the present embodiment, when the power hydraulic pressure disappears, only the small diameter first piston 11 operates, so that the cross-sectional area becomes relatively small, and as shown by the broken line, the power hydraulic pressure disappears. The wheel cylinder hydraulic pressure (that is, the pressure in the pressure chamber R2) when a predetermined brake depression force is applied increases.

For example, if a large depression force is applied to the brake pedal 2 during the anti-skid control, or if a large depression force is applied to the brake pedal 2 even after the hydraulic pressure control of the auxiliary hydraulic pressure source 40 is completed, the pressure chamber R2 Fluid pressure rises,
It becomes larger than the hydraulic pressure in the power chamber R1. Further, the pressure chamber R2
The hydraulic pressure in the power chamber R1 becomes larger than the hydraulic pressure in the power chamber R1 by a predetermined pressure or more.
When the brake fluid in the power chamber R1 flows backward to the zero accumulator 44, the second piston 12 retreats and the first piston 11 moves forward. However, in the present embodiment, as shown in FIGS.
A check valve 60 is interposed in the hydraulic passage between the hydraulic pressure passage 4 and the hydraulic passage 1p of the regulator section, and the flow of the brake fluid in the direction of the accumulator 44 is blocked.
Even when a large pedaling force is applied to the second piston 12
Never retreat suddenly. Therefore, the first piston 1
A good brake feeling can be maintained without the situation where the brake pedal 2 advances suddenly and the brake pedal 2 suddenly enters.

In addition, since the check valve 60 is provided with the spring 62, the valve body 61 can be disposed in the upside down direction.
There is no risk that the valve will open due to gravity. Check valve 6
Since 0 is disposed downstream of the hydraulic pressure sensors PH and PL (the regulator section side), there is no possibility that an error occurs in the detection of the output power hydraulic pressure of the auxiliary hydraulic pressure source 40 by the hydraulic pressure sensors PH and PL.

[0035]

Since the present invention is configured as described above, the following effects can be obtained. That is, in the vehicle hydraulic brake device of the present invention, the master cylinder piston is disposed so as to be relatively slidable with respect to the first piston connected to the brake operating member, and the master cylinder piston is moved forward during forward movement. A second piston engaged with the first piston,
The rear end of each of the first and second pistons is exposed to the power chamber, and the front end of each is arranged to be exposed to the pressure chamber. The output power hydraulic pressure of the auxiliary hydraulic pressure source is supplied to the pressure regulating valve means. Since a check valve is interposed in the hydraulic passage to be supplied, the check valve prevents the flow of the brake fluid from the pressure regulating valve means to the auxiliary hydraulic pressure source. Thus, when the output hydraulic pressure of the auxiliary hydraulic pressure source is sufficient, the master cylinder is boosted by the output hydraulic pressure of the pressure regulating valve means according to the operation of the brake operating member, and the output hydraulic pressure of the auxiliary hydraulic pressure source is not sufficient. When sufficient, the master cylinder can be driven directly according to the operation of the brake operating member, and not only can the appropriate braking operation be performed only by the master cylinder, but also the check valve prevents the backflow of brake fluid to the auxiliary hydraulic pressure source. Therefore, even when a large operation force is applied to the brake operation member, the operation feeling is not impaired, and a good brake feeling can be maintained.

According to a second aspect of the present invention, in the hydraulic brake system for a vehicle, a pressure detecting means is connected to a hydraulic pressure path for supplying an output power hydraulic pressure of an auxiliary hydraulic pressure source to a pressure regulating valve means. In other words, if a check valve is interposed between the connection part of the pressure detecting means and the pressure regulating valve means, no error occurs when detecting the output power hydraulic pressure of the auxiliary hydraulic pressure source, and the detection can be performed appropriately. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of a hydraulic brake device for a vehicle according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a master cylinder unit according to the embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a regulator section according to an embodiment of the present invention.

FIG. 4 is a graph showing brake hydraulic pressure characteristics in one embodiment of the present invention.

[Explanation of symbols]

 1h Cylinder body 2 Brake pedal 4 Reservoir 10 Master cylinder piston 11 First piston 12 Second piston 21 Control piston R1 Power room R2 Pressure room R3 Regulator room R4 Pressure transmission room R5 Liquid supply room R6 Closed space

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihisa Nomura 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (2)

[Claims] A master cylinder piston is slidably housed in a cylinder body in a liquid-tight manner, and a pressure chamber is formed in front of the master cylinder piston and a power chamber is formed behind the master cylinder piston. A master cylinder that drives the master cylinder piston forward to output brake fluid pressure from the pressure chamber, an auxiliary fluid pressure source that boosts brake fluid to a predetermined pressure and outputs power fluid pressure, A control piston disposed in front of the master cylinder piston so as to be slidable in a liquid-tight manner and arranged so as to interlock with the master cylinder piston, and an output power hydraulic pressure of the auxiliary hydraulic pressure source according to the movement of the control piston. Pressure regulating valve means for regulating the pressure to a predetermined pressure, and applying the brake fluid pressure regulated by the pressure regulating valve means to the power chamber of the master cylinder. A hydraulic brake device for a vehicle that assists driving of a brake operating member, wherein the master cylinder piston is disposed slidably relative to a first piston connected to the brake operating member and the first piston. And a second piston engaged with the first piston during forward movement, exposing a rear end of each of the first and second pistons to the power chamber, and connecting a front end of the pressure chamber to the pressure chamber. In the hydraulic path for supplying the output power hydraulic pressure of the auxiliary hydraulic pressure source to the pressure regulating valve means,
A hydraulic brake device for a vehicle, further comprising a check valve for allowing a flow of brake fluid from the auxiliary hydraulic pressure source to the pressure regulating valve means and preventing a flow in a reverse direction. 2. A pressure detecting means for detecting an output power hydraulic pressure of the auxiliary hydraulic pressure source is connected to a hydraulic pressure passage for supplying an output power hydraulic pressure of the auxiliary hydraulic pressure source to the pressure regulating valve means. 2. The hydraulic brake device for a vehicle according to claim 1, wherein said check valve is interposed between a connection portion of a detecting means and said pressure regulating valve means.