JPH0780447B2 - Hydraulic brake device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake device, and in particular, in addition to a tandem master cylinder, a power hydraulic pressure supplied from a power hydraulic pressure source is applied to a brake pedal. The present invention relates to a hydraulic brake device including a dynamic hydraulic pressure control device for outputting and connecting the dynamic hydraulic pressure control device to one pressure chamber of the tandem master cylinder.

[Prior Art] In a regular brake system of a vehicle, hydraulic piping between a wheel cylinder mounted on a wheel and a brake hydraulic pressure control system such as a master cylinder is multi-system, and when one system is broken, the remaining system is used. The braking ability is to be secured. A tandem master cylinder is used in two general systems.

On the other hand, in order to reduce the operating force of the brake pedal during braking, a booster called a servo or booster is installed, and compressed air, intake pipe negative pressure (negative pressure booster), fluid hydraulic pressure (hydraulic pressure booster) are used as boosting sources. ) Is used. The hydraulic booster uses the power hydraulic pressure output from the power hydraulic pressure source as a boosting source to boost the brake hydraulic pressure control device such as a master cylinder in response to a brake pedal.
For example, Japanese Patent Application Laid-Open No. 59-209948 discloses a hydraulic booster arranged in a tandem master cylinder, which is configured to operate as a normal tandem master cylinder when the hydraulic booster is not operated. There is.

With the adoption of this hydraulic booster, it has been proposed that, in the brake hydraulic pressure control device, in addition to the master cylinder, the hydraulic booster function as a dynamic hydraulic pressure control device. That is, the brake hydraulic pressure (hereinafter referred to as boost hydraulic pressure) controlled by responding to the brake pedal by inputting the power hydraulic pressure is directly applied to one system. For example, as disclosed in JP-A-59-227552, a boost hydraulic pressure of a hydraulic booster is applied to the rear wheel side in the front-rear split type to shorten the stroke of the brake pedal.

Furthermore, regarding a brake fluid pressure control device equipped with a tandem master cylinder and a hydraulic booster, one pressure chamber of the tandem master cylinder is connected to the wheel cylinder of one system, and the hydraulic pressure is applied to the wheel cylinder of many systems. It has been proposed to output booster boost hydraulic pressure via the other pressure chamber of the tandem master cylinder. That is,
It is disclosed in Japanese Patent Laid-Open No. 62-155167, and various effects such as shortening the stroke of the brake pedal can be obtained.

[Problems to be Solved by the Invention] However, in the former prior art (Japanese Patent Laid-Open No. 59-227552), when the power hydraulic pressure disappears due to the stop of the power hydraulic pressure source or the like, the front wheel side is braked by the master cylinder. However, there is a problem that the braking force on the rear wheel side is completely lost.

On the other hand, according to the latter conventional technique, when the power hydraulic pressure of the power hydraulic pressure source disappears, the function as an ordinary tandem master cylinder is ensured and the braking force of all wheels is secured.

However, regarding the shortening of the pedal stroke in the latter prior art, since the disclosed tandem master cylinder is a type that utilizes the sliding action of the orifice port that communicates with the reservoir and the piston that opens and closes this, the brake initial operation is performed. Even if the second piston temporarily slides in the first piston direction, that is, in the brake pedal direction, the first piston, the first pressure chamber, and the system communicating therewith are not affected, and thus such an operation is performed. Is considered to be out of control, and shortening the stroke is only a direct effect of using a hydraulic booster, which is a dynamic hydraulic pressure control device. Therefore, there is still an initial dead stroke when actuating the first piston.

Therefore, the present invention is not limited to the shortening of the stroke by applying the output hydraulic pressure of the dynamic hydraulic pressure control device by one system of the tandem master cylinder, and the initial invalid stroke of the tandem master cylinder is reduced to further reduce the stroke of the brake pedal. The purpose is to shorten the

[Means for Solving Problems] In order to solve the above problems and achieve the above object, the present invention adopts the following configuration.

That is, in the hydraulic brake device of the present invention, the inside of the cylinder hole is formed by the first piston that slides in response to the brake pedal in the cylinder hole formed in the housing and the second piston that slides in response to the one piston. A first pressure chamber and a second pressure chamber, the brake fluid is introduced into the first pressure chamber and the second pressure chamber, and the brake fluid is reduced according to the sliding of the first piston and the second piston, respectively. A tandem master cylinder that outputs pressure, a power hydraulic pressure source that boosts brake fluid to a predetermined pressure to output power hydraulic pressure, and a power hydraulic pressure that is output from the power hydraulic pressure source are input to respond to the brake pedal. And a dynamic hydraulic pressure control device for outputting the adjusted brake hydraulic pressure, and the first pressure chamber and the second pressure chamber of the tandem master cylinder are provided to the wheel cylinders of each wheel of the vehicle as two hydraulic passages. Split While passing connected and communicatively connected to one of the pressure chambers of the tandem master cylinder to the dynamic fluid pressure control apparatus. The tandem master cylinder defines a first liquid supply chamber and a second liquid supply chamber between the cylinder hole and the first piston and the second piston, and the tandem master cylinder is attached to the first piston to attach the first pressure chamber. The first liquid supply chamber communicates with the first pressure chamber through a normally open first valve body that closes when the chamber shrinks, and is attached to the second piston and closed when the second pressure chamber shrinks. The second liquid supply chamber is communicated with the second pressure chamber via a normally open second valve body that is valved, and the dynamic liquid pressure control device is communicatively connected to the second liquid supply chamber, A sliding distance when the second piston slides in the first piston direction by a brake hydraulic pressure supplied from the dynamic hydraulic pressure control device to the second pressure chamber via the second liquid supply chamber, , The first with the sliding of the second piston
A locking means is provided to limit the sliding distance of the second piston in the direction of the first piston when the first valve body is closed by reducing the pressure chamber to a predetermined distance.

As the locking means, a bolt that is screwed to a housing between the first piston and the second piston and has a tip extending into the first pressure chamber or a cylinder hole in the first pressure chamber is fitted, A cylindrical collar having a flange portion at an end portion facing the second piston may be used.

[Operation] In the above hydraulic brake device, when a pedaling force is applied to the brake pedal, the power hydraulic pressure output from the power hydraulic pressure source is input to the dynamic hydraulic pressure control device and is adjusted in response to the brake pedal. The regulated brake fluid pressure is output to the second fluid supply chamber of the second piston of the tandem master cylinder. This brake fluid pressure is passed through the second valve body of the second piston to the second
It is transmitted to the pressure chamber and supplied to the wheel cylinder communicating with it. Therefore, as compared with the conventional tandem master cylinder, the brake fluid pressure is supplied without going through the process of sliding the first piston and the sliding of the second piston, so that the stroke of the brake pedal is shortened. At the same time, the output fluid pressure of the dynamic fluid pressure control device causes the second piston to slide in the direction of the first piston to reduce the first pressure chamber and close the first valve body of the first piston, and then to the locking means. Move until it abuts.

As a result, when the first piston starts sliding in response to the brake pedal, the moving distance until the first valve body is closed is unnecessary, and the ineffective stroke is reduced accordingly. Furthermore, since the brake fluid initially absorbed in the first pressure chamber and the system communicating with the first pressure chamber is filled in advance, the stroke amount during this period is reduced and the rise of the brake fluid pressure is accelerated.

Then, when the output hydraulic pressure of the dynamic hydraulic pressure control device disappears due to the disappearance of the power hydraulic pressure or the like, it functions as an original tandem master cylinder, and so-called static hydraulic pressure is applied to all wheels.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. A brake fluid pressure control device 1 includes a tandem master cylinder 10 and a fluid pressure booster 20, and the fluid pressure booster 20 is referred to as dynamic fluid pressure control in the present invention. It is used as a device. As a result, the pedaling force applied to the brake pedal 2 is transmitted as a brake actuating force via the input rod 3, and accordingly, the brake hydraulic pressure input from the reservoir 41 or the power hydraulic pressure source 40 is controlled as appropriate. It is output to the wheel cylinders 51a to 54a of the front wheels 51, 52 and the rear wheels 53, 54 via the roads 71, 72.

First, the tandem master cylinder 10 has a first cylinder hole 10a formed in the housing 1a and a first cylinder hole 10a formed in the cylinder hole 10a.
The piston 11 and the second piston 15 are slidably fitted in a liquid-tight manner. A small diameter land portion and a large diameter land portion are formed at both ends of the first piston 11, and a small diameter portion and a large diameter portion are also formed in the cylinder hole 10a so as to be adapted to these, and are formed as stepped holes. In the large diameter portion of the cylinder hole 10a, the first liquid supply chamber 13 is provided between the small diameter land portion and the large diameter land portion of the first piston 11.
The first pressure chamber 12 is defined between the small diameter land portion of the first piston 11 and the second piston 15 in the small diameter portion of the cylinder hole 10a. The first pressure chamber 12 communicates with the hydraulic pressure passage 71 through the port 12a, and the first liquid supply chamber 13 communicates with the reservoir 41 through the port 13a.

The first piston 11 has an axial hole from both ends toward the center.
11a and 11b are formed, and a hole 11c is formed in the radial direction. And a small hole in which the hole 11a and the hole 11c are formed in the axial direction.
It communicates with 11d. Further, a hole 11e is formed in the peripheral direction, and the opening end on the first pressure chamber 12 side is covered with the cup seal 11f, which constitutes a check valve. In the hole 11a of the first piston 11, a first valve body 14a (hereinafter simply referred to as the valve body 14a) attached to one end of the valve rod 14 has a small hole 11d.
It is slidably housed so as to be opposed to the retainer 14c and its movement toward the second piston 15 is restricted by the retainer 14c. Valve rod 14
The large diameter end of the other end is a hole 15b formed in the second piston 15.
It is slidably accommodated in the retainer 14b and its movement toward the first piston 11 is restricted by the retainer 14b. The head of the output rod 4 is housed in the hole 11b.

A return spring 14d is stretched between the retainers 14b and 14c and urges the first piston 11 and the second piston 15 so as to separate from each other. Therefore, in a normal state, both ends of the valve rod 14 are retained by the retainers 14b and 14c. It will be in the state of being locked to. Thus, the valve body 14a and the small hole 11d are separated from each other, and the brake fluid supplied from the reservoir 41 to the first liquid supply chamber 13 via the port 13a passes through the hole 11e of the first piston 11 and The first pressure chamber 12 is filled through the holes 11c, the small holes 11d, and the holes 11a. Therefore, from this state, the first piston 11 resists the return spring 14d and the second piston 1
When pressed and slid in 5 directions, hole 11e is created by the cup seal.
However, the small hole 11d is closed by the valve body 14a, and the first pressure chamber 12 is in a sealed state except for the output port of the port 12a, so that the brake fluid is pressurized with the sliding of the first piston 11.

The second piston 15 is arranged between the closed end portion 10b of the cylinder hole 10a and the first piston 11, and like the first piston 11, is slidably fitted in the cylinder hole 10a in a liquid-tight manner. Land portions of the same diameter are formed on both ends of the second piston 15,
The second liquid supply chamber 17 is defined between both lands, and the second pressure chamber 16 is defined between the land and the closed end 10b. The second pressure chamber 16 communicates with the hydraulic passage 72 through the port 16a, and the second liquid supply chamber 17 communicates with the hydraulic passage 73 through the port 17a.

Like the first piston 11, the second piston 15 also has an axial hole 15a,
15b and a radial hole 15c are provided. Hole 15a and hole 15c
And are communicated with each other through an axial small hole 15d. Further, a hole 15e is formed in the peripheral portion axial direction, and the opening end on the second pressure chamber 16 side is covered with the cup seal 15f. In the hole 15a of the second piston, a second valve body 18a (hereinafter simply referred to as valve body 18a) attached to one end of the valve rod 18 is slidably accommodated facing the small hole 15d and closed by a retainer 18c. Movement in the direction of the portion 10b is restricted. The large-diameter end of the other end of the valve rod 18 is slidably supported by the retainer 18b, and the second piston 15
Movement in the direction is restricted. A return spring 18d is stretched between the retainers 18b and 18c, and the second piston 1
5 is urged in a direction away from the closed end portion 10b, and therefore the valve body 18a is in a state of being separated from the small hole 18d in the normal state.

Then, when the output hydraulic pressure is applied to the second liquid supply chamber 17 via the hydraulic pressure passage 73 and the port 17a by the hydraulic pressure booster 20 which will be described later, through the hole 15e and through the small hole 15d and the hole 15a. Is transmitted to the second pressure chamber 16. At the same time, a pressing force that moves in the direction of the first piston 11 is applied to the land portion of the second piston 15, and the second piston 15 slides in the same direction.

Further, when the output hydraulic pressure of the hydraulic booster 20 does not exist in the hydraulic pressure passage 73, when the first piston 11 slides in the direction of the second piston 15, the first pressure chamber 12 is contracted and the pressure is increased.
The piston 15 slides against the return spring 18d. As a result, the small hole 15d is closed by the valve body 18a, and the brake fluid in the second pressure chamber 16 is pressurized.

Housing 1a between the first piston 11 and the second piston 15
Is provided with a bolt 19 as a locking means according to the present invention. The head of the bolt 19 extends into the cylinder hole 10a,
The movement of the piston 15 in the direction of the first piston 11 is restricted. The normal position of the second piston 15, that is, the first piston 11
The distance S1 between the bolt 19 and the initial position determined by the return springs 14d and 18d without any pressing force is at least the distance S2 between the opening end of the small hole 11d of the first piston 11 and the valve body 14a. Large, first piston of second piston 15
Due to the contraction of the first pressure chamber 12 due to the movement in the 11th direction, the hydraulic pressure passage 71 and the wheel cylinders 53a, 54a of the system communicating with the first pressure chamber 12 have a movement distance sufficient to fill the initial brake fluid. Is set. However, if the distance S1 is excessively large, the first piston 11 is in a so-called non-travel state, so that the first piston 11 itself is limited to a predetermined length.

Next, the hydraulic booster 20 will be described together with the brake input mechanism.

The hydraulic booster is installed on the housing 1b that joins with the housing 1a.
The 20 double pressure chambers 20a and the low pressure chambers 20b are formed, and the power piston 5 is slidably and liquid-tightly inserted into a hole 20c that communicates the two chambers substantially coaxially with the cylinder hole 10a. There is. The power piston 5 is provided with a retainer 6 at the end portion on the brake pedal 2 side, and is biased in the brake pedal 2 direction by a spring 6a stretched between the retainer 6 and the housing 1b. A shoulder portion is formed at an intermediate portion of the power piston 5, and the shoulder portion abuts the housing 1b to prevent sliding in the direction of the brake pedal 2. A recess 5a is formed in the end portion of the power piston 5 on the first piston 11 side, and a mounting hole is bored in the central axial direction. This stepped hole is composed of a small-diameter hole 5b, a medium-diameter hole 5c, a large-diameter hole 5d and an open hole 5e. The reaction rod 22r fitted in the small-diameter hole 5b and the medium-diameter hole 5
A reaction force piston 22 having a small diameter portion and a large diameter portion which are respectively fitted in c and the large diameter hole 5d is slidably accommodated.
The axial length of the reaction force rod 22r is set to be at least longer than that of the small diameter hole 5b. In the radial direction of the reaction force piston 22, a long hole 22a having a long axis in the axial direction and a through hole 22b orthogonal to the long hole 22a are formed.
Has been drilled. A pin 5h fixed to the power piston 5 is fitted into the long hole 22a, and the sliding of the reaction force piston 22 in the direction of the brake pedal 2 is restricted with respect to the power piston 5.

A ball bearing is formed at the large diameter end of the reaction force piston 22. Then, a spherical head formed at the other end of the input rod 3 whose one end is connected to the brake pedal 2 is inserted into the open hole 5e of the power piston 5 and is housed in the ball bearing of the reaction force piston 22. It is locked by the protrusion formed on. In the radial direction of the power piston 5, the reaction force piston 22 is in the normal state where the reaction force piston 22 is located closest to the brake pedal 2 side.
A large diameter through hole 5f is formed by overlapping with b.

In addition, between the medium diameter hole 5c and the reaction force rod 22r, this and the small diameter portion 5
An annular space is formed due to the difference in axial length from b, and a slanted hole 5g is formed to connect the annular space and the low pressure chamber 20b. A large-diameter end of the output rod 4 is housed in the recess 5a of the power piston 5 via an elastic reaction disc 4a and is locked by a leaf spring or the like. The reaction disc 4a and the end of the reaction rod 22r are connected to each other. A gap is formed between them. The output rod 4 is a hole for the first piston 11.
It is inserted in 11b, and the head is in contact with the bottom surface of the hole 11b.

In the hole 22b of the reaction force piston 22, one end is pivotally attached to the housing 1b by the pin 1c, and the support lever 24 swings in the double pressure chamber 20a.
The spherical head of is fitted. And this support lever
One of the heads of the control lever 25, which is rotatably joined to each other by a pin 24a at approximately the center of the hole 24, has a hole for the power piston 5.
It is fitted to 5f. Therefore, when the reaction force piston 22 slides in the direction of the output rod 4 with respect to the power piston 5 pressed toward the brake pedal 2, a force for rotating the support lever 24 clockwise about the pin 1c is applied to the support lever 24. At this time, since one head of the control lever 25 is held in the hole 5f of the power piston 5, the other head of the control lever 25 rotates counterclockwise about the piston 24a as an axis to move the reaction piston. Since the reaction force rod 22r moves in the sliding direction of 22, the displacement corresponding to the movement distance until the reaction force rod 22r contacts the reaction disc 4a is formed.

The housing 1b has a double pressure chamber 20 substantially parallel to the power piston 5.
A spool valve hole communicating with a is formed, and a spool valve 28, which is a hydraulic pressure control valve, is fitted in the hole. The spool valve 28 has a spool 27 slidably accommodated in a spool hole 27a formed in the cylinder 27 substantially parallel to the power piston 5, and one end of the spool hole 27a is sealed with a plug 27f.

The spool 26 is provided with a hole 26a penetrating in the axial direction and a radial throttle hole 26b communicating with the hole 26a, and one end of the spool 26 is located in the pressure doubler chamber 20a and is connected to one end of the control rod 29. . The other end of the control rod 29 is slidably supported by the housing 1b, and the head of the control lever 25 is fitted in a through hole 29a bored in the radial direction.

A spring 29c is stretched between a retainer 29b supported at one end of the control rod 29 and the cylinder 27, and the spool 2c
6 is biased toward control lever 25. Incidentally, spool 2
At the joint between 6 and the control rod 29, the hole 26a is always a double pressure chamber.
It opens to 20a.

At the stop position of the control lever 25, the other end side of the hole 26a of the spool 26 is a hole 27b bored in the radial direction of the cylinder 27, a hole 27d communicating with this through an outer peripheral groove of the cylinder 27, and these holes 27d. Then, they communicate with the reservoir 41 and the low-pressure chamber 20b via the ports provided in the housing 1b, respectively.
Therefore, the pressure-doubled chamber 20a also communicates with the reservoir 41 and is filled with the brake fluid under the atmospheric pressure.

The cylinder 27 has a control rod 29 at a predetermined distance from the hole 27b.
A hole 27c communicating with the power hydraulic pressure source 40 is also formed on the side, but is blocked by the peripheral surface of the spool 26 at this position. An annular groove 27e is formed between this hole 27c and the end surface of the spool 26 on the control rod 29 side, and an annular groove 26c is formed on the outer periphery of the spool 26 so as to face the annular groove 27e.

Thus, the spool 26 moves when the control lever 25 moves,
When sliding in the 27f direction, the hole 27b of the cylinder 27 is blocked,
Instead, the hole 27c faces the groove 26c of the spool 26, the groove 27e faces the throttle hole 26b, and thus communicates with the hole 26a.

That is, the power hydraulic pressure of the power hydraulic pressure source 40 is transmitted into the double pressure chamber 20a to increase the pressure and the reaction force is transmitted to the brake pedal 2 via the reaction force piston 22, and at the same time, the increased hydraulic pressure causes the power piston 5 to move. It is transmitted to the first piston 11 via. At this time, the power piston 5 moves with respect to the reaction force piston 22 at the longest until the pin 5h engages with the long hole 22a. This allows
The positional relationship between the control lever 25 and the support lever 24 is the same as in the initial state, so that the control lever 25 rotates relatively clockwise and the control rod 29 retracts in the direction of the brake pedal 2. Then, the hole 27c of the cylinder 27 is blocked, and instead the hole 27b communicates with the hole 26a of the spool 26 and the double pressure chamber 20.
The pressure in a decreases and the power piston 5 moves toward the brake pedal 2. By repeating such an operation, the power hydraulic pressure in the double pressure chamber 20a is controlled to a predetermined boost hydraulic pressure.

The port 20d provided in the housing 1b and communicating with the double pressure chamber 20a is connected to the tandem master cylinder 1 via the hydraulic passage 73.
It communicates with the port 17a provided at 0 and communicates with the second grade liquid chamber 17. Therefore, the output hydraulic pressure of the double pressure chamber 20a is applied to the second liquid supply chamber 17.

The power hydraulic pressure source 40 is provided with a hydraulic pump 43 driven by an electric motor 42, the input side is connected to the reservoir 41, the output side is connected to the accumulator 44 via the check valve 45, and the necessary position is set via the accumulator 44. The power hydraulic pressure is supplied. The power hydraulic pressure is maintained at a predetermined pressure by an electric motor 42 which is intermittently connected by a control circuit (not shown) in response to a signal from a pressure sensor (not shown).

To explain the operation of the above embodiment, FIG. 1 shows a state in which the brake pedal 2 is not operated, the first pressure chamber 12 and the first liquid supply chamber 13 of the tandem master cylinder 10 communicate with each other, and the rear wheels respectively.
Since the wheel cylinders 53a, 54a of the wheels 53, 54 are connected to the reservoir 41, the brake fluid filled therein is under the pressure in the reservoir 41, that is, substantially atmospheric pressure.

On the other hand, the power hydraulic pressure of the power hydraulic pressure source 40 is applied to the hole 27c of the hydraulic booster 20. In this state, since the hole 27c is blocked, the hydraulic booster 20 is not functioning.

The brake fluid in the second pressure chamber 16 and the second liquid supply chamber 17 is a port
17a, the hydraulic passage 73, the port 20d, the pressure-doubled chamber 20a, and the reservoir 41, which communicate with the reservoir 41 via the hole 27b, and are under substantially atmospheric pressure. Therefore, the wheel cylinder 51a communicating with the port 16a, the hydraulic passage 72,
52a is also under the same pressure.

When the pedal force is applied to the brake pedal 2, the input rod 3
When the reaction force piston 22 is pushed through the reaction force rod 22r and moves until the reaction force rod 22r contacts the reaction disc 4a of the power piston 5, the control lever 25 rotates counterclockwise with respect to the support lever 24, and the head moves to the spool 26. Press. As a result, as described above, the power hydraulic pressure from the power hydraulic pressure source 40 is introduced to press the power piston 5 to apply a double pressure to the first piston 11, and at the same time, to the brake pedal via the reaction force piston 22. The reaction force is transmitted to 2. Port at the same time
Power hydraulic pressure is applied to the second liquid supply chamber 17 from 20d, is output to the second pressure chamber 16 via the holes 15d and 15e, and is output to the hydraulic pressure passage 72 from the port 16a and transmitted to the wheel cylinders 51a, 52a. It The second piston 15 slides toward the first piston 11 due to the power hydraulic pressure input into the second liquid supply chamber 17, and first the valve body 14a closes the communication passage 11d until the bolt 19 abuts. 1 The pressure chamber 12 is reduced.

As a result, the hydraulic pressure passage 71 communicating with the first pressure chamber 12 and the initial brake fluid in the wheel cylinders 53a, 54b are filled, and as soon as the first piston 11 starts sliding by the power piston 5, the wheel cylinder 53a is immediately stopped. Brake fluid pressure is output to 54a. On the other hand, in the double pressure chamber 20a, the relative displacement between the power piston 5 and the reaction piston 22 and the corresponding control lever 25 driving the spool valve 28 to maintain the power hydraulic pressure at a predetermined pressure (boost hydraulic pressure). It will be.

As is clear from the above operation, the hydraulic pressure booster 20 causes the wheel cylinders 51a, 52 before the first piston 11 slides.
Since the brake fluid pressure is output to a, the stroke of the brake pedal 2 is shortened and the second piston 15
Since the valve body 14a closes the communication passage 11d by the movement of, the ineffective stroke corresponding to the movement distance S1 during this period is eliminated. Furthermore, since the first pressure chamber 12 is reduced due to the sliding of the second piston 15, the system communicating with the first pressure chamber 12 is filled with the initial brake fluid. Therefore, the stroke required for this is reduced and the brake fluid is also reduced. The pressure rises quickly and the braking force is linear with respect to the brake pedal stroke.

Then, even if the power hydraulic pressure disappears due to a failure of the power hydraulic pressure source 40 and the hydraulic booster 20 stops operating and the double pressure disappears, in the tandem master cylinder 10, the first piston 11 causes the brake pedal 2 to move. To pressurize the first pressure chamber 12 and slide the second piston 15 to move the second pressure chamber 16
To function as a normal tandem master cylinder.

In this way, even when the power hydraulic pressure of the power hydraulic pressure source 40 disappears, it functions similarly to the conventional tandem master cylinder. Diagonal piping does not require complicated adjustments.

FIG. 2 shows a second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals, and the main difference from the first embodiment is the locking means referred to in the present invention. The point is that a collar 30 is used instead of the bolt 19 in FIG.

That is, the cylinder hole 10c is a stepped hole having a large diameter portion and a small diameter portion, and an annular recess 31 is formed on the end surface that abuts the housing 1b. A cylindrical collar 30 is fitted to the large diameter portion of the cylinder hole 10c, and an annular projecting portion 30b formed on the peripheral surface.
Is sandwiched between the recess 31 and the housing 1b.

A stepped hole 30a is formed on the inner surface of the collar 30. The stepped hole 30a includes a small diameter portion having the same diameter as the small diameter portion of the cylinder hole 10c and a large diameter portion having substantially the same diameter as the large diameter land portion of the first piston 11. The first piston 11 is housed in the bore 30a. One end of the collar 30 is opened to the low pressure chamber 20b of the hydraulic booster 20, and the other end is formed with an annular flange portion 30c having a diameter smaller than the land portion of the second piston 15, and the second piston of the large diameter portion of the cylinder hole 10c. It is in contact with the end on the 15 side. The flange portion 30c and the second piston 15 are separated by the distance S1 in the normal state. Further, an annular groove 30d is formed on the peripheral surface of the collar 30, and a port is provided through the communication hole 30e.
31a communicates with the first liquid supply chamber 13. Also, the flange part 3
A groove 30f is formed in 0c to connect the first pressure chamber 12 and the port 12a.

Thus, the collar 30 reliably regulates the sliding of the second piston 15 in the direction of the first piston 11. Moreover, color
The distance S1 can be adjusted by appropriately changing the axial length of 30. Further, an opening / closing valve 60 is attached to the hydraulic pressure passage 73, and a check valve 60a is installed in parallel with this. The opening / closing valve 60 is controlled by the relay 61 controlled by the output signal of the liquid amount sensor 41a provided in the reservoir 41 to control the solenoid coil 60a.
Is a 2-port 2-position solenoid valve in which the hydraulic passage 73 is opened and closed by being excited / de-energized. In this embodiment, a normally open valve is used. Therefore, the double pressure chamber 20a and the secondary liquid chamber 1 are always
7 communicates with each other, and when, for example, the fluid level sensor 41a detects that the brake fluid level is insufficient, the relay 61 is activated and the solenoid coil
The opening / closing valve 60 is closed and the hydraulic passage 73 is shut off by exciting 60a. If necessary, the opening / closing valve 60 may be a normally closed valve and the reverse operation may be performed, and instead of the liquid amount sensor 41a, a pressure sensor (not shown) that detects the output hydraulic pressure of the power hydraulic pressure source 40 responds. May be

Then, when the output hydraulic pressure of the hydraulic booster 20 disappears, the second piston 15 slides due to the brake hydraulic pressure of the first pressure chamber 12 and the valve body 18a closes the communication passage 15d, as in the first embodiment. The brake fluid pressure in the second pressure chamber 16 is increased to function as a normal tandem master cylinder. On the other hand, when a liquid leak occurs in the system of the wheel cylinders 51a, 52a on the front wheels 51, 52 due to an accident or the like, the amount of liquid in the reservoir 41 decreases and a signal is output from the liquid amount sensor 41a. 61 operates and the on-off valve 60 is switched to the closed side. This makes the first
Brake fluid pressure is prevented from flowing out to the system communicating with the pressure chamber 12 and the rear wheels 53, 54 are retained while the function of the hydraulic booster 20 is maintained.
Braking force is applied to the side. Since the other configurations, operations and effects are the same as those of the first embodiment, the description thereof will be omitted.

Although the hydraulic booster 20 is used as the dynamic hydraulic pressure control device according to the present invention in the first and second embodiments, for example, a negative pressure booster is used as the booster and the spool valve 28 of the hydraulic booster 20 is used. It is also possible to attach a pressure adjusting mechanism including the above as a separate body and connect this to the second liquid supply chamber 17 of the tandem master cylinder 10.

[Advantages of the Invention] As described above, according to the present invention, the output hydraulic pressure of the dynamic hydraulic pressure control device during brake pedal operation is supplied to the second liquid supply chamber of the second piston of the tandem master cylinder. Two
Not only the brake pedal stroke is shortened with respect to the system communicating with the pressure chamber, but also the second piston slides in the direction of the first piston until it abuts with the locking means in the initial stage of depression of the brake pedal to communicate with the first pressure chamber. With respect to the system as well, the effect that the initial invalid stroke is reduced and the stroke is further shortened as a whole is obtained. In addition, the second
The sliding of the piston causes the first pressure chamber to shrink, and the system that communicates with the first pressure chamber is filled with brake fluid, which contributes to shortening the ineffective stroke, resulting in a quick start-up and a linear response to the brake pedal stroke. There is an effect that the braking force is obtained and the braking characteristic has a good feeling.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a hydraulic brake device of the present invention, and FIG. 2 is an overall configuration diagram showing another embodiment of the same. 2 …… Brake pedal, 10 …… Tandem master cylinder,
11 …… First piston, 12 …… First pressure chamber, 13 …… First liquid supply chamber, 14a, 18a …… Valve element, 15 …… Second piston, 16 …… Second pressure chamber, 17 …… Second liquid supply chamber, 19 ... Bolt (locking means), 20
…… Hydraulic booster, 30 …… Collar (locking means), 40 ……
Power hydraulic pressure source, 41 …… reservoir, 51a to 54a …… wheel cylinder, 60 …… open / close valve, 71 to 73 …… hydraulic pressure path

Front Page Continuation (72) Inventor Yoshihiko Tako, Asahi-cho 2-chome, Kariya city, Aichi Prefecture, Aisin Seiki Co., Ltd. (72) Inventor Yoshihisa Nomura, Toyota-cho, Aichi prefecture Toyota-cho, Ltd. (72) Inventor Masahiko Kato 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor Kenji Shirai 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor, Junichi Akami Aichi 1 Toyota Town, Toyota City, Japan (56) References JP 62-155167 (JP, A) JP 62-181951 (JP, A) JP 62-8874 (JP, U) )

Claims (5)

[Claims] 1. A first piston that slides in response to a brake pedal in a cylinder hole formed in a housing, and the first piston.
A second piston, which slides in response to the piston, defines a first pressure chamber and a second pressure chamber in the cylinder hole, and introduces brake fluid into the first pressure chamber and the second pressure chamber, respectively. A tandem master cylinder that contracts according to sliding of the first piston and the second piston to output brake fluid pressure, a power hydraulic pressure source that boosts the brake fluid to a predetermined pressure and outputs power hydraulic pressure, and the power fluid A first hydraulic chamber and a second hydraulic chamber of the tandem master cylinder are provided, which include a dynamic hydraulic pressure control device that presses a power hydraulic pressure output from a pressure source and outputs a brake hydraulic pressure adjusted in response to the brake pedal. Is connected to the wheel cylinder of each wheel of the vehicle by dividing it into two hydraulic passages for communication and connecting one pressure chamber of the tandem master cylinder to the dynamic hydraulic control device. On the device There are, the tandem master cylinder is KakuNaru the first fluid chamber and second fluid chamber between the first piston and the second piston and the cylinder bore, the first
The first liquid supply chamber communicates with the first pressure chamber via a normally open first valve body that is attached to a piston and closes when the first pressure chamber is contracted, and is attached to the second piston. Second
The second liquid supply chamber communicates with the second pressure chamber via a normally open second valve body that closes when the pressure chamber is reduced.
While connecting the dynamic hydraulic pressure control device to the liquid supply chamber,
The second hydraulic pressure control device supplies the second hydraulic pressure control device to the second hydraulic pressure chamber via the second hydraulic pressure supply chamber to supply the second hydraulic pressure to the second pressure chamber.
The sliding distance when the piston slides in the direction of the first piston is the first distance when the first valve body is closed by the reduction of the first pressure chamber accompanying the sliding of the second piston. A hydraulic brake device comprising locking means for restricting a predetermined distance larger than a sliding distance of the two pistons in the first piston direction. 2. The bolt according to claim 1, wherein the locking means is a bolt which is screwed to a housing between the first piston and the second piston and has a tip extending into the first pressure chamber. The hydraulic brake device according to item 1. 3. The locking means is a cylindrical collar fitted in a cylinder hole in the first pressure chamber and having a flange portion formed at an end portion facing the second piston. The hydraulic brake device according to claim 1. 4. A housing in which the dynamic hydraulic pressure control device is connected to the tandem master cylinder, an input rod which slides in a pressure double chamber formed in the housing in association with the brake pedal, and the input. A hydraulic pressure control valve that responds to a rod and outputs a boost hydraulic pressure into the double pressure chamber by inputting the power hydraulic pressure of the power hydraulic pressure source, and slides in the double pressure chamber to respond to the boost hydraulic pressure. A hydraulic booster comprising a power piston for driving the first piston of the tandem master cylinder via an output rod, and the hydraulic booster according to any one of claims 1 to 3. The hydraulic brake device described. 5. The hydraulic brake device according to claim 4, wherein the double pressure chamber of the hydraulic booster is connected to the second liquid supply chamber via an opening / closing valve.