JPH01278873A - Hydraulic braking device - Google Patents

Abstract

PURPOSE:To prevent a brake fluid from flowing out to a wheel cylinder from a dynamic hydraulic controller via a hydraulic passage with certainty even at the time of vehicle stoppage by installing a normally-opened valve gear in the hydraulic passage leading to a second supplying chamber from the dynamic hydraulic controller. CONSTITUTION:A hydraulic passage, interconnecting a second suppling chamber 17 to a dynamic hydraulic controller 20, is usually in a state of being interrupted by a normally-opened valve gear 60. When this valve gear 60 is driven and opened, and leg power is added to a brake pedal 2, power fluid pressure outputted by a power fluid pressure source 40 is inputted into the dynamic hydraulic controller 20 and regulated in response to the brake pedal 2, and thereby output fluid pressure is directly given to wheel cylinders 51a-54a. With this operation, a stroke of the brake pedal 2 is reduced. If drive of the valve gear 60 is released attendant upon vehicle stoppage or the like, it comes to a stead state, namely, a valve closing position whereby the hydraulic passage leading to the second supplying chamber 17 from the dynamic hydraulic controller 20 is interrupted, so that interconnection with the wheel cylinder is interrupted as well.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle brake system, and more particularly, to a vehicle brake system that uses power hydraulic pressure supplied from a power hydraulic pressure source in addition to a tandem master cylinder in response to a brake pedal. The present invention relates to a hydraulic brake device including a dynamic hydraulic pressure control device for outputting output, and the dynamic hydraulic pressure control device is communicatively connected to one of the fluid supply chambers of the tandem master cylinder.

[Prior Art] In the service brake system of a vehicle, there are multiple systems of hydraulic piping between the wheel cylinder attached to the wheel and the brake fluid pressure control device such as a mask cylinder, so that when one system is damaged, the remaining system is The aim is to ensure braking ability. 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 the booster is compressed air and intake pipe negative pressure (negative pressure booster).
, fluid hydraulics (hydraulic booster) are used. The hydraulic pressure booster uses the power hydraulic pressure output from the power hydraulic pressure source as a boosting source to boost and drive a brake hydraulic pressure control device such as a master cylinder in response to a brake pedal. For example, Japanese Unexamined Patent Publication No. 59-209948 discloses a tandem master cylinder in which a hydraulic booster is disposed, and this is configured to operate as a normal tandem master cylinder when the hydraulic booster is not in operation. There is.

Along with the adoption of this hydraulic pressure booster, it has been proposed to have the hydraulic pressure booster function as a dynamic hydraulic pressure control device in addition to the mask cylinder in the brake hydraulic pressure control device. In other words, a brake fluid pressure (lower than the brake fluid pressure C, which is referred to as a boost fluid pressure) controlled in response to the brake pedal by inputting the power fluid pressure is directly applied to one system. For example, as shown in Japanese Unexamined Patent Publication No. 59-227552, boost hydraulic pressure from a hydraulic booster is applied to the rear wheel side of a front-rear split type brake pedal in order to shorten the stroke of the brake pedal.

Furthermore, regarding a brake hydraulic pressure control device equipped with a tandem master cylinder and a hydraulic pressure booster, one pressure chamber of the tandem master cylinder is connected to one system of wheel cylinders, and the hydraulic pressure is connected to one system of wheel cylinders. It has been proposed to output the boost hydraulic pressure of the booster via the other pressure chamber of the tandem master cylinder. That is,
This is disclosed in Japanese Unexamined Patent Publication No. 155167/1983, and various effects such as shortening the stroke of the brake pedal can be obtained.

However, the former prior art (Japanese Patent Laid-Open No. 59-227552
In the No. 1), if the power hydraulic pressure disappears due to a stoppage of the power hydraulic pressure source, etc., there is a problem in that, although braking force is secured for the front wheels by the mask cylinder, there is no braking force for the rear wheels. be.

On the other hand, according to the latter prior art, when the power hydraulic pressure of the power hydraulic pressure source disappears, it functions as a normal tandem master cylinder and ensures braking force for all wheels. Also,
A normally open on-off valve is provided in the supply path of pressurized liquid (boost liquid pressure) to the working chamber (pressure chamber), and this on-off valve is operated when the accumulator's liquid pressure (power liquid pressure) falls below a predetermined value. The valve is configured to close at certain times. Therefore, even if the wheel cylinder of the system to which pressurized fluid is supplied and the hydraulic pressure path leading to it are damaged due to a vehicle collision, resulting in fluid leakage, this will prevent it from affecting other systems. Ru.

[Problems to be Solved by the Invention] However, in the latter prior art, the on-off valve is configured to be open at all times, so if a failure occurs in the on-off valve or the control means that controls it, There is a risk that the normal state will be maintained and the valve will not be able to close. Furthermore, if the above-mentioned failure is left unaddressed, the on-off valve may be in the volume valve state while the vehicle is stopped, and there is a risk that brake fluid may flow out.

Although such a situation would not occur under normal usage conditions, and the possibility that the brake fluid would completely flow out is low, in the present invention, in order to further prepare for unexpected situations, the pressurized fluid is always supplied. The purpose of this system is to control the system so that it is disconnected and connected when necessary.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration.

That is, the hydraulic brake device of the present invention includes a reservoir for storing brake fluid, a first piston that slides in response to a brake pedal within a cylinder hole formed in a housing, and a first piston that slides in response to the first piston. A second piston defines a first pressure chamber, a second pressure chamber, a first liquid supply chamber, and a second liquid supply chamber in the cylinder hole, and a tandem master cylinder that introduces the brake fluid from the reservoir into the first pressure chamber and the second pressure chamber and outputs brake fluid pressure by reducing the brake fluid pressure according to the sliding of the first piston and the second piston, respectively; A power hydraulic pressure source that increases the pressure to a predetermined pressure and outputs power hydraulic pressure, and inputs the power hydraulic pressure outputted from the power hydraulic pressure source and outputs the regulated brake hydraulic pressure in response to the brake pedal. A dynamic hydraulic pressure control device is provided, the first pressure chamber and the second pressure chamber of the tandem master cylinder are communicatively connected to a wheel cylinder mounted on each wheel of the vehicle, and a second fluid supply chamber of the tandem master cylinder is provided. is connected to the dynamic hydraulic pressure control device, and a normally closed valve device is interposed in a hydraulic pressure path that communicates the second liquid supply chamber and the dynamic hydraulic pressure control device.

The normally closed valve device includes a valve means that normally shuts off the hydraulic pressure path, and a valve means that communicates the hydraulic pressure path when a start switch of an engine mounted on the vehicle is turned on to start the engine. It may be provided with a control means for driving.

The control means further includes brake operation detection means for detecting an operation state of the brakes of the vehicle, and when the brake operation detection means detects that the brake is not activated and the start switch is turned on to start the engine, the valve is activated. It is preferable to use a means for driving the means and controlling the hydraulic pressure path to communicate with each other.

Preferably, the control means includes a hydraulic pressure detecting means for detecting the output power hydraulic pressure of the power hydraulic pressure source, and a fluid volume detecting means for detecting the brake fluid volume in the reservoir, and the control means is configured to detect the brake fluid volume in the reservoir. and a detection signal of the hydraulic pressure detecting means, at least when the output power hydraulic pressure of the power hydraulic pressure source is below a predetermined pressure, and when the amount of brake fluid in the reservoir is below a predetermined amount. It is preferable to include means for controlling the valve means so as to prohibit the driving thereof when either of the above is the case.

[Operation] In the above-mentioned hydraulic brake device, the hydraulic pressure path communicating the second fluid supply chamber and the dynamic hydraulic pressure control device is normally closed by the normally closed valve device. When the normally closed valve device is driven to open and a pedal 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 regulated in response to the brake pedal. Output hydraulic pressure is applied directly to the wheel cylinder. Therefore, compared to a conventional tandem master cylinder, brake fluid pressure is supplied without going through the process of sliding the first piston and then sliding the second piston, so the stroke of the brake pedal is shortened. When the drive of the normally closed valve device is released due to the vehicle stopping, etc., it becomes the normal state, that is, the valve closed position, and the hydraulic pressure path from the dynamic hydraulic pressure control device to the second fluid supply chamber is cut off, and the wheel cylinder and communication is cut off.

If the normally-closed valve device is equipped with a normally-closed valve means and a control means that drives the normally-closed valve means in response to an engine start switch, the valve means opens when the engine of the vehicle is started and the above-mentioned stroke shortening operation is performed. will be carried out.

Moreover, when the engine is stopped, the valve means immediately returns to its normal state and the hydraulic pressure path is cut off.

In addition, if the vehicle is equipped with a brake operation detection means and a control means for controlling according to the output signal of the brake operation detection means, the valve means will not be driven even if the engine start switch is turned to the start side when the brake is applied. The hydraulic path is maintained in a blocked state.

In a device equipped with a hydraulic pressure detection means, a liquid volume detection means, and a control means that performs control according to the output signals of these, for example, fluid leakage may occur in a wheel cylinder connected to a dynamic hydraulic pressure control device. When this occurs, the detection means detects a decrease in the power hydraulic pressure or the brake fluid amount, and the control means controls the valve means to shut off the hydraulic pressure path.

[Embodiments] Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a brake fluid pressure control device 1 includes a tandem master cylinder 10 and a fluid pressure booster 20, and this fluid pressure booster 20 is a dynamic fluid pressure control device according to the present invention. It is used as. As a result, the pedal force applied to the brake pedal 2 is transmitted as a brake actuation force via the manual rotor 3, and the brake hydraulic pressure input from the reservoir 41 or the power hydraulic pressure source 40 is appropriately controlled accordingly. ．． The wheel cylinders 5 of the front wheels 51.52 and rear wheels 53.54 are connected through the second hydraulic pressure passages 71 and 72.
1a to 54a.

First, in the tandem master cylinder 10, a first piston 11 and a second piston 15 are slidably fitted in a cylinder hole 10a formed in a housing 1a in a fluid-tight manner.

A small-diameter land portion and a large-diameter land portion are formed at both ends of the first piston 11, and the cylinder hole 10 is formed to fit the small-diameter land portion and the large-diameter land portion.
A is also formed with a small diameter portion and a large diameter portion to form a stepped hole.

The first piston 11 is located within the large diameter portion of the cylinder hole 10a.
A first liquid supply chamber 13 is formed between the small diameter land portion and the large diameter land portion of the cylinder hole 10a, and a first pressure chamber is formed between the small diameter land portion of the first piston 11 and the second piston 15 within the small diameter portion of the cylinder hole 10a. 12 are constructed. Furthermore, this first pressure chamber 1
2 communicates with the first hydraulic pressure path 71 through the boat 12a, and
The liquid supply chamber 13 communicates with the reservoir 41 through a boat 13a.

The first piston 11 is provided with holes 11a and ttb in the axial direction from both ends toward the center, and a hole 11c in the radial direction. The holes 11a and 11c communicate with each other via a small hole lid formed in the axial direction. In addition, a hole 11e is bored in the axial direction of the peripheral edge, and the first pressure chamber 1
The open end on the second side is covered with a cup seal llf, thereby forming a check valve. A valve body 1 is attached to one end of the valve rod 14 in the hole 11a of the first piston 11.
4a is slidably housed facing the small hole lid, and its movement in the direction of the second piston 15 is restricted by a retainer 14c. The large diameter end of the other end of the valve rod 14 is slidably accommodated in a hole 15b formed in the second piston 15, and movement toward the first piston 11 is restricted by a retainer 14b.

Note that the output rod 4 is accommodated in the hole flb of the first piston 11. A return spring 14d is stretched between the retainers 14b and 14C, and biases the first piston 11 and the second piston 15 away from each other. It will be in a locked state.

Thus, the valve body 14a and the small hole lid are separated from each other, and the first liquid supply chamber 1 is supplied from the reservoir 41 via the boat 13a.
3 is supplied to the hole li of the first piston 11.
It is filled into the first pressure chamber 12 through the hole 11C1, the small hole lid, and the hole 11a. Therefore, from this state, when the first piston 11 is pushed against the return spring 14d and slid in the direction of the second piston 15, the hole lie is closed by the cup seal Ilf, and the small hole lid is closed by the valve body 14a, and the first piston 11 The pressure chamber 12 is in a sealed state except for the output port of the boat 12a, and the first
The pressure of the brake fluid is increased regardless of the sliding movement of the piston 11.

The second piston 15 is disposed between the closed end 10b of the cylinder hole 10a and the first piston 11, and like the first piston 11, is slidably fitted into the cylinder hole 10a in a liquid-tight manner. Land portions with the same diameter are formed at both ends of the second piston 15, and a second liquid supply chamber 17 is formed between both land portions, and a second pressure chamber 16 is formed between the two land portions and the closed end portion 10b. is constructed. This second pressure chamber 16 is opened by the boat 16a.
The second liquid supply chamber 17 communicates with the hydraulic pressure path 72, and communicates with the fifth hydraulic path 75 through a boat 17a, and communicates with the reservoir 41 through a check valve 41c through a boat 17b.

Similarly to the first piston 11, the second piston 15 also has a hole 1 in the axial direction.
5a, 15b and a radial hole 15c are bored.

The holes 15a and 15c communicate with each other via a small axial hole 15d. Further, a hole 15e is bored in the axial direction of the peripheral edge, and the opening end on the second pressure chamber 16 side is connected to the cup seal 1.
It is covered with 5f. A valve body 18a attached to one end of the valve rod 18 is inserted into the small hole 15a of the second piston.
d, and is slidably accommodated in the opposite direction, and its movement toward the closed end 10b is restricted by a retainer 18c.

The large diameter end of the other end of the valve rod 18 is slidably supported by a retainer 18b, and movement in the direction of the second piston 15 is restricted. A return spring 18d is stretched between the retainers 18b and 18c, and the second piston 15 is urged in a direction away from the closed end 10b, but movement in the direction of the first piston 11 is restricted by the bolt 19. ing. That is, the bolt 19 is screwed into a screw hole drilled in the radial direction of the housing 1a, and its tip end is connected to the second liquid supply chamber 17.
It protrudes inward, and its side end face faces the land portion of the second piston 15. Therefore, the bolt 19 is connected to the second piston 1.
5, it acts as a locking member to restrict movement in the direction of the first piston 11.

Note that the locking member is not limited to a bolt, and a bottle or the like may be used. Under normal conditions, the valve body 18a is in a state separated from the small hole 15d, and the second liquid supply chamber 17 and the The two pressure chambers 16 are filled with brake fluid from a reservoir 41 via boats 17a and 17b.

Therefore, 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 second piston 15 slides against the return spring 18d. As a result, the small hole 15d is closed by the valve body 18a, and the pressure of the brake fluid in the second pressure chamber 16 is increased. Also,
The normally closed on-off valve 60, which will be described later, is opened, and the output hydraulic pressure of the hydraulic pressure booster 20, which will be described later, is transferred to the second liquid supply chamber via the S4 hydraulic pressure path 74, the on-off valve 60, the fifth hydraulic pressure path 75, and the boat 17a. 17
When the pressure is applied to , it is transmitted to the second pressure chamber 16 through the hole 15e, and also through the small hole 15d and the hole 15a. At the same time, a pressing force is applied to the land portion of the second piston 15 in the direction of the first piston 11, but the second piston 15 is locked to the bolt 19 and does not move.

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

A pressure doubler chamber 20a and a low pressure chamber 20b of a hydraulic pressure booster 20 are formed in the housing 1b that joins the housing 1a, and a hole 20c that is substantially coaxial with the cylinder hole 10a and communicates between the two chambers is formed in a liquid-tight manner. A power piston 5 is slidably inserted. This power piston 5 is the brake pedal 2
A retainer 6 is provided at the side end, and is urged in the direction of the brake pedal 2 by a spring 6a stretched between the retainer 6 and the housing 1b. A shoulder is formed in the middle of the power piston 5, and this shoulder comes into contact with the housing 1b to prevent the brake pedal from sliding in the direction of the brake pedal 2. A recess 5a is formed at the end of the power piston 5 on the first piston 11 side, and a hole 5b and a hole 5e with a larger diameter are bored in the axial direction of the center portion. A communication hole is bored at the bottom of the hole 5b, and the reaction force piston 22 is slidably accommodated in the hole 5b.

A long hole 22a having a long axis in the axial direction and a through hole 22b orthogonal to the long hole 22a are bored in the radial direction of the reaction force piston 22. A pin 5h fixed to the power piston 5 is fitted into the elongated hole 22a to restrict sliding of the reaction force piston 22 relative to the power piston 5 at least in the direction of the brake pedal 2. 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 hole 5e of the power piston 5, and is accommodated in the open end of the reaction force piston 22. It is locked with a protrusion formed on the inner surface. In the radial direction of the power piston 5, a through hole 5f is formed which overlaps the through hole 22b and has a larger diameter when the reaction force piston 22 is located closest to the brake pedal 2 side. The output rod 4 is accommodated in the recess 5a of the power piston 5. The output rod 4 is inserted into the hole 11b of the first piston 11, and its head is in contact with the bottom surface of the hole 11b.

One end of the hole 22b of the reaction force piston 22 is connected to the housing 1.
A spherical head of a support lever 24 which is pivoted on pin 1C and swings within double pressure %20a is fitted to b. One head of the control lever 25, which is rotatably joined to the support lever 24 by a pin 24a, is fitted into the hole 5f of the power piston 5. The other head of the control lever 25 is formed with a cam slot that engages the pin 1c of the support lever 24.

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 side, a force is applied to the support lever 24 to rotate it clockwise about the pin 1c. At this time, the control lever 25
Since one head of the uHN lever 25 is held in the hole 5f of the power piston 5, the other head of the uHN lever 25 is held in the pin 24a.
The cam slot is guided by the pin 1c and moves 8 times in the same direction as the sliding direction of the reaction force piston 22, and the reaction force piston 22 comes into contact with the bottom of the hole 5b. A displacement corresponding to the eight movement distances up to this point is formed.

A spool valve hole is formed in the housing 1b substantially parallel to the power piston 5 and communicates with the pressure doubler chamber 20a, into which a spool valve 28 functioning as a hydraulic pressure control valve is fitted. The spool valve 28 has a spool 26 slidably housed 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 stopper 27f. .

The spool 26 has a hole 26a penetrating in the axial direction and a radial throttle hole 26b communicating with the hole 26a, one end of which is located in the pressure doubler chamber 20a and connected to one end of the control rod 29. . The other end of the control rod 29 is a housing! A through hole 29a is slidably supported by b and is bored in the radial direction.
The head of the control lever 25 is fitted into the top of the control lever 25 . A retainer 29b supported at one end of this control rod 29 and a cylinder 2
A spring 29c is stretched between the spool 26 and the spool 26.
is biased toward the pin 1c.

Note that the hole 26a at the joint between the spool 26 and the control rod 29 is always open to the pressure doubler chamber 20a. At the stop position of the control lever 25, the other end side of the hole 26a of the spool 26 communicates with the reservoir 41 via a hole 27b formed in the radial direction of the cylinder 27. Therefore, the double pressure chamber 20
The inside a also communicates with the reservoir 41 and is filled with brake fluid under atmospheric pressure.

A hole 27c is bored in the cylinder 27 at a predetermined distance from the hole 27b and communicates with the power hydraulic pressure source 40 on the @control rod 29 side, but at this position it is blocked by the circumferential surface of the spool 26. . 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 27e is formed on the outer periphery of the spool 26 opposite to this.
f426c is formed.

When the spool 26 slides in the direction of the stopper 27f by the eight movements of the control lever 25, the hole 27b of the cylinder 27 opens.
is blocked, and instead the hole 27c is opened to the full 26c of the spool 26.
The aperture 27e and the throttle hole 26b are opposed to each other, and therefore communicate with the hole 26a.

That is, the power hydraulic pressure of the power hydraulic pressure source 40 is transmitted to the pressure doubler chamber 20a and increased in pressure, and a 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 increase in pressure. The signal is transmitted to the first piston 11 via the signal.

At this time, the power piston 5 moves eight times at maximum against the reaction force piston 22 until the pin 5h engages with the elongated hole 22a.

As a result, the positional relationship between the control lever 25 and the support lever 24 becomes the same as the initial state, so the control lever 25 rotates clockwise, and the control rod 29 moves toward the brake pedal 24.
will retreat in the direction of Then, the hole 27c of the cylinder 27 is blocked, and the hole 27b instead communicates with the hole 26a of the spool 26, so that the pressure in the pressure doubler chamber 20a decreases, and the power piston 5 moves eight times in the direction of the brake pedal 2. By repeating such operations, the power hydraulic pressure in the pressure doubler chamber 20a is controlled to a predetermined boost hydraulic pressure.

The first pressure chamber 12 of the tandem master cylinder 10
is connected to one system, that is, in this embodiment, to the wheel cylinders 53a, 54a of the rear wheels 53.
The second hydraulic pressure path 7 is connected to the wheel cylinders 51a and 52a of 52.
It communicates via 2. Note that this hydraulic system may be reversed for the front and rear wheels, if necessary, or may be configured as diagonal piping. A boat 20d provided in the housing 1b and communicating with the pressure doubler chamber 20a is connected to a normally closed on-off valve 6 via a fourth hydraulic pressure path 74.
0, and the on-off valve 60 communicates with the boat 17a provided in the tandem master cylinder 10 via the fifth hydraulic pressure path 75. Therefore, when the on-off valve 60 is open, the pressure doubler chamber 20
The output hydraulic pressure of a is applied to the second liquid supply chamber 17.

The power hydraulic pressure source 40 includes a hydraulic pump 43 driven by an electric motor 42, the input end of which is connected to a reservoir 41, and the output end connected to an accumulator 44 via a check pulp 45. It is configured such that power hydraulic pressure is supplied to.

Note that this power hydraulic pressure is maintained at a predetermined pressure by intermittent control of the electric motor 42 in accordance with a signal from a pressure sensor 40a, which will be described later.

The on-off valve 60 is a normally closed two-bottom, two-position solenoid valve that opens when a drive signal is supplied to the solenoid 60a, and constitutes the valve means of the normally closed valve device according to the present invention. Open/close valve 60
is interposed between the fourth hydraulic pressure path 74 and the fifth hydraulic pressure path 75,
A check valve is arranged in parallel with this and is used for returning the brake fluid when the pressure on the fourth hydraulic pressure path 74 side becomes lower than that on the fifth hydraulic pressure path 75 side.

Opening/closing control of the on-off valve 60 is performed by a control circuit 90 which is a control means of the normally closed valve device according to the present invention. Control circuit 9
0 is connected to the engine start switch 80 of the vehicle in which the brake fluid pressure control device 1 is installed, that is, generally the ignition switch of an internal combustion engine, and when the start switch 80 is turned on to start the engine, the control circuit 90, an H (high) level signal is output. In addition, "when the starting switch is turned on to the engine starting side" as used in this application includes not only the ON operation of the ignition switch, but also includes, for example, a state in which an ignition switch having an accessory contact turns on the internal combustion by the starting switch. The purpose is to include the engine start preparation operation. Therefore, other switches or sensors may be used instead of the ignition switch.

The control circuit 90 normally outputs an L (low) level signal, and when the power hydraulic pressure of the power hydraulic pressure source 40 is below a predetermined hydraulic pressure, the hydraulic pressure sensor 40a outputs an H level signal.
It is connected to the. Also, the power hydraulic pressure source 4 of the reservoir 41
Depending on the level of brake fluid in the fluid chamber that communicates with 0,
Fluid level sensor 41a that normally outputs an L level signal and outputs an H level signal when the brake fluid level is below a predetermined level.
It is connected to the. Furthermore, it is connected to a brake sensor 2a which detects the operating state of the brake and outputs an L level signal normally and an H level signal when the brake is operated.

That is, the hydraulic pressure sensor 40a, the liquid amount sensor 41a, and the brake sensor 2a correspond to a hydraulic pressure detecting means, a liquid amount detecting means, and a brake operation detecting means, respectively, in the present invention. Note that the hydraulic pressure sensor 40a may also be used as a pressure sensor for controlling the electric motor 42 of the power hydraulic pressure source 40 as in this embodiment, or a pressure switch that is conductive at a predetermined pressure or less may be used. As the liquid level sensor 41a, a conventional liquid level sensor can be used, and a level switch that conducts at a predetermined liquid level or less can be used. Further, a conventional brake pedal switch for lighting a brake lamp or a pressure switch provided in a brake fluid pressure path may be used as the brake sensor 2a.

The control circuit 90 described above is configured as shown in FIG. That is, the start switch 80 is connected to the set terminal of the flip-flop 93 via the AND circuit 91, and the hydraulic pressure sensor 40a and the liquid level sensor 41a are connected to the reset terminal of the flip-flop 93 via the OR circuit 92. . The Q output terminals of the flip-flops 9 and 3 are connected to the solenoid Boa via a drive circuit 94. Further, the output of the brake sensor 2a is inverted and connected to the set terminal of the flip-flop 95, and the output terminal of the OR circuit 92 is connected to the reset terminal of the flip-flop 95. The Q output terminal of the flip-flop 95 is connected to the input terminal of the AND circuit 91.

Therefore, if brake pedal 2 is not depressed,
Since the output of the brake sensor 2a is at L level, the flip-flop 95 is set, and the AND circuit 91 becomes H level. At this point, if the power hydraulic pressure and the brake fluid volume both exceed predetermined values, the hydraulic pressure sensor 40a and the fluid volume sensor 41a both output L level outputs, so the flip-flop 93 is not reset. In this state, when the start switch 80 is turned on to start the engine and outputs an H level, the output of the AND circuit 91 goes to H level, the flip-flop 93 is set, the Q output goes to H level, and the drive circuit 94 is driven. .

Therefore, the solenoid 60a is energized and the on-off valve 60 is opened.

Then, when at least one of the fluid pressure sensor 40a and the fluid amount sensor 41a becomes an H level output, that is, when the power fluid pressure or the brake fluid amount becomes less than a predetermined value, the flip-flops 93 and 95 are reset, and the flip-flop 9
The Q output of No. 3 becomes L level, the solenoid Boa is de-energized, and the on-off valve 60 returns to the closed position.

On the other hand, when the brake pedal 2 is depressed before the start switch 80 is turned to the engine start side, the output of the brake sensor 2a is at the H level, so the flip-flop 95 is not set. Therefore, one input of the AND circuit 91 is at the L level, and even when the start switch 80 is turned on, the flip-flop 93 is not set and the solenoid 60a is not energized. That is, the on-off valve 60 remains in the closed position. Note that when the engine stops, the operation of the power hydraulic pressure source 40 also stops, and the power hydraulic pressure becomes less than a predetermined pressure, and the flip-flops 93 and 95 are reset, but the start switch 80 is returned to the engine stop side. It may be reset from time to time.

Further, the output signal level of each of the above-mentioned sensors may have an inverse relationship, that is, the output signal level becomes L level when it is equal to or higher than a predetermined value, and the control circuit 90 is not limited to the above, but can be configured with various circuits.

To explain the operation of the embodiment configured as above, FIG. 1 shows the state when the brake pedal 2 is not operated, the first pressure chamber 12 of the tandem master cylinder 10 and the first fluid supply chamber 13 are in communication, Wheel cylinders 53a for rear wheels 53° and 54, respectively
, 54a and the reservoir 41, the brake fluid filled in these is under the pressure within the reservoir 41, that is, approximately atmospheric pressure.

On the other hand, the power hydraulic pressure of the power hydraulic pressure source 40 is
0 hole 27c. In this state, the hole 27c
is shut off, so the hydraulic booster 20 is not functioning.

Since the brake fluid in the second pressure chamber 16 and the second fluid supply chamber 17 communicates with the reservoir 41 via the port 17b and the check valve 41c and is under approximately atmospheric pressure, Communication sliding wheel cylinder 51a
, 52a are also under the same pressure. In addition, the boat 17a has an on-off valve 6.
0 is in the normal closed position, so it is disconnected from the hydraulic booster 20.

When the start switch 80 is turned to the engine starting side in the above state, if the amount of brake fluid in the reservoir 41 is sufficient and the output power hydraulic pressure of the power hydraulic pressure source 40 is sufficient, the brake sensor 2a, the hydraulic pressure sensor The outputs of the solenoid 40a and the liquid level sensor 41a both become L level, and a drive signal is output from the control circuit 90 to the solenoid 60a, and the on-off valve 60 is operated to be in the open position. Therefore, the pressure doubler chamber 20a of the hydraulic pressure booster 20
The second hydraulic pressure chamber 17 communicates with the double pressure chamber 20a, but the hole 2
Since it communicates with the reservoir 41 via 7b, it is at approximately atmospheric pressure.

When pedal force is applied to the brake pedal 2, the manual lot 3
When the reaction force piston 22 is pressed and moves eight times until it comes into contact with the power piston 5, the control lever 25 rotates counterclockwise with respect to the support lever 24, and its head presses the spool 26. As a result, as described above, the power hydraulic pressure source 40
The power hydraulic pressure from is introduced to press the power piston 5 and apply double pressure to the first piston 11,
The reaction force is transmitted to the brake pedal 2 via the reaction force piston 22.

At the same time, the output hydraulic pressure is applied from the port 20d to the second liquid supply chamber 17 via the on-off valve 60 in the open position, and the output hydraulic pressure is applied directly to the wheel cylinders 51a and 52a. Then, when the first piston 11 starts sliding by the power piston 5, the small hole lid is closed by the valve body 14a, and as the first pressure chamber 12 contracts, the wheel cylinder 53a
, 54a, the brake fluid pressure is output. On the other hand, double pressure chamber 2
Inside 0a, the power hydraulic pressure is maintained at a predetermined pressure (boost hydraulic pressure) by the relative displacement between the power piston 5 and the reaction force piston 22 and the corresponding drive of the spool valve 28 by the control lever 25.

As is clear from the above operation, before the first piston 11 slides, the hydraulic booster 20 causes the wheel cylinder 5 to
Brake fluid pressure is output to 1a and 52a, and the stroke of the brake pedal 2 is shortened.

Next, for example, due to an accident, the wheel cylinders 51a, 5
When 2a is damaged and brake fluid leaks, the amount of brake fluid in the reservoir 41 decreases, and the output power hydraulic pressure of the power hydraulic pressure source 40 decreases. Then, when the brake fluid level becomes less than a predetermined amount or the power fluid pressure becomes less than a predetermined pressure,
The liquid level sensor 41a or the liquid pressure sensor 40a outputs an H level, the drive signal of the drive circuit 94 is not supplied, the solenoid 60a becomes de-energized, the on-off valve 60 returns to its normal state, that is, the closed position, and the pressure doubler chamber 20a and the The two liquid supply chambers 17 are cut off. Therefore, the brake fluid in the pressure doubler chamber 20a is prevented from flowing out from the wheel cylinders 51a, 52a, and the double pressure is maintained, and the pressure of the first pressure chamber 12 increases in response to the brake pedal 2 on the first piston 11 side. Therefore, the braking force on the rear wheels 53 and 54 is maintained. Moreover, since the reservoir 41 is divided into three fluid chambers as shown in FIG. 1, the amount of brake fluid on the first piston 11 side is ensured.

Alternatively, even if the operation of the power hydraulic pressure source 40 stops for some reason and the double pressure disappears, the on-off valve 60 returns to its normal closed position, and the first piston 11 in the tandem master cylinder 10 moves to the brake pedal 2. In response to this, the first pressure chamber 12 is increased in pressure, and the second piston 15 is slid to increase the pressure in the second pressure chamber 16, thereby functioning as a normal tandem master cylinder.

In the above embodiment, the operation of the on-off valve 60 is summarized as follows. That is, the on-off valve 6o is a normally closed valve, and opens in conjunction with the engine start switch 80. however,
The valve opening operation is prohibited under any of the following conditions when opening the valve. That is, when (a) the output power hydraulic pressure of the power hydraulic pressure source 40 falls below a predetermined pressure, (b) the reservoir 41
(c) When the brake pedal 2 is depressed when starting the engine, that is, when the start switch 80 is turned on, brake operation is detected by the brake sensor 2a. When you are there,
When the on-off valve 60 is in the open state, the valve is closed if at least one of (a) and (b) above occurs.

Therefore, when the brake pedal 2 is depressed when starting the engine, the on-off valve 60 does not open even if the start switch 8o is turned to the engine start side, giving the driver a pedal shock, a so-called kickback. Never. and,
Even if a failure occurs in the wheel cylinders 51a, 52a, the hydraulic pressure path 72, etc. leading to them, or in the unlikely event that a failure occurs in the solenoid 60a of the on-off valve 60 and the electric circuit leading thereto, the on-off valve 60 will remain closed in its normal state. Since it is maintained in position, brake fluid will not leak out. In particular, since the on-off valve 60 is in the normal closed position even when the vehicle is parked or stopped with the engine stopped, brake fluid will not leak out.

FIG. 3 shows another embodiment of the control circuit shown in FIG.
From FIG. 2, the brake sensor 2a and the flip-flop 95
is removed, and the output of the OR circuit 92 is inverted and input to the AND circuit 91. In the control circuit 90a, the outputs of the hydraulic pressure sensor 40a and the liquid volume sensor 41a serve as reset inputs to the flip-flop 93 which has priority on reset. Therefore, if any of these outputs is at H level when the start switch 80 is turned on or when the on-off valve 60 is in the open position, the flip-flop 93
is reset and the solenoid 60a is de-energized. Incidentally, since the subsequent operation is similar to that of the embodiment shown in FIG. 3, the explanation thereof will be omitted.

FIG. 4 shows another embodiment of the present invention, in which the same parts as in the embodiment of FIG. 1 are given the same reference numerals, and anti-lock and anti-slip control Switching valves 65, 66, 87 and supply/discharge valves 61 to 64 are provided.

The first pressure chamber 12 of the tandem master cylinder 10 is a single system part, and in this embodiment, the first hydraulic pressure passage 71 and the first
The switching valve 65, the seventh hydraulic pressure path 77, and the supply/discharge valves 63, 64
The second pressure chamber 16 is connected to another system, that is, to the wheel cylinders 51a and 52a of the front wheels 51 and 52.
The hydraulic pressure passage 72, the third switching valve 67, the third hydraulic pressure passage 73, and the supply/discharge valves 61 and 62 communicate with each other. On the other hand, the hydraulic booster 20 is connected to the third switching valve 67 via the fourth hydraulic pressure path 74, and the on-off valve 60 and the fifth hydraulic pressure path 75
The second fluid supply chamber 17 of the tandem master cylinder 10 via
It will be communicated to. Further, the power hydraulic pressure source 40 is communicatively connected to the second switching valve 66 via a ninth hydraulic pressure path 79. The second switching valve 66 is connected to the hydraulic booster 20 via the sixth hydraulic pressure path 76.
It is connected to the first switching valve 65 via an eighth hydraulic pressure path 78. It should be noted that the first hydraulic pressure path 71 and the sixth hydraulic pressure path 76 are provided with a known blobbing bypass valve 68 and a blobbing valve 69, respectively.

The first switching valve 65 is composed of a 3-point, 2-position solenoid valve driven by a solenoid 65a, and is normally set in the first hydraulic pressure path 7.
1 and the seventh hydraulic pressure path 77 and block the eighth hydraulic pressure path 78, and when activated, the seventh hydraulic pressure path and the eighth hydraulic pressure path are communicated and the first hydraulic pressure path 71 is blocked. It is switched to the second position.

The second switching valve 66 is also composed of a 3-point, 2-position solenoid valve driven by a solenoid 66a, and is normally operated in the ninth hydraulic pressure path 7.
9 is shut off, the sixth hydraulic pressure path 76 and the eighth hydraulic pressure path 78 are communicated, and the first switching valve 65 is communicated with the hydraulic pressure booster 20. During operation, the sixth hydraulic pressure path 76 is shut off, the eighth hydraulic pressure path 78 and the ninth hydraulic pressure path 79 are communicated, and the first switching valve 65 is connected to the power hydraulic pressure source 4.
Connects to 0.

Further, the third switching valve 67 is also driven by the solenoid 67a.
This is a one-point, two-position solenoid valve that is normally located at the position shown in Figure 1, and when activated, the third hydraulic pressure path 73 and the fourth hydraulic pressure path 74 communicate
It communicates with the hydraulic pressure booster 20.

These first to third switching valves 65, 66, and 67 are switched and controlled by a control device 100 equipped with a microcomputer, and during anti-lock control, the second switching valve 66 is in an inactive state, and the first switching valve 65 and the third switching valve The switching valve 67 operates,
During anti-slip control, the third switching valve 67 is inactive, first the first switching valve 65 is activated, and then the second switching valve 66 is activated.
is controlled so that it operates.

The on-off valve 60 is a normally closed two-bottom valve 2, similar to the embodiment shown in FIG.
It is composed of a positional solenoid valve, and normally blocks off the fifth hydraulic pressure path 75. Then, the control device 100 inputs the output signal of the fluid sensor 41a provided in the reservoir 41 or the output signal of the pressure sensor 40a provided in the power hydraulic pressure source 40, and detects a lack of brake fluid amount by the fluid amount sensor 41a, for example. Then, the on-off valve 60 is set to the normal closed position, or is controlled to return to the closed position when the hydraulic pressure sensor 40a indicates a decrease in power hydraulic pressure. Moreover, the control device 10
The output signal of the brake sensor 2a is also input to 0, and it is controlled to operate in the same manner as the embodiment shown in FIG.

The supply/discharge valves 61 and 62 are three-bottom, three-position solenoid valves that communicate the wheel cylinders 51a and 52a with the third switching valve 67 in the first position, shut off the valves in the second position, and communicate with the reservoir 41 in the third position. Normal brake operation is normally performed at the first position, and the first to third positions are appropriately selected during anti-lock operation to adjust the brake fluid pressure.

Similar supply/discharge valves 63,64 for the rear wheels 53,54 are connected to the wheel cylinders 53a, 54a.

In this embodiment, when the start switch 80 is turned on to start the engine when the brake is not activated, the on-off valve 60 opens and the hydraulic booster 20 and the second pressure chamber 16 communicate with each other. At this time, the first to third switching valves 65 to 67
The supply and discharge valves 61 to 64 are located as shown in FIG. When a pedal force is applied to the brake pedal 2, the front wheel 51
52 is the rear wheel 53 due to the output hydraulic pressure of the hydraulic pressure booster 20.
．． 54 performs a braking operation by the output hydraulic pressure of the first pressure chamber 12.

When the brake pedal 2 is depressed before the start switch 80 is turned to the engine start side, the on-off valve 60 is maintained in the closed position, and so-called kickback is avoided.

Next, when the slip state of the wheels is detected during brake operation and anti-lock control is started, the first switching valve 65 and the third switching valve 67 are operated by the control device 100, and the supply/discharge valves 61 to 64 are equipped with a hydraulic booster. 20 output hydraulic pressures are supplied, three positions of each of the supply/discharge valves 61 to 64 are appropriately selected depending on the locked state of rotation of the front and rear wheels 51 to 54, and the hydraulic pressure in the wheel cylinders 51a to 54a is adjusted. Ru.

On the other hand, when the control device 100 detects slippage of the rear wheels 53, 54, which are the drive wheels, when the vehicle starts or accelerates, the first switching valve 65 is operated and the first hydraulic pressure path 71 is shut off. . Next, the second switching valve 66 is operated to switch the wheel cylinder 53a.

Power hydraulic pressure is applied to 54a. That is, braking force is applied to the rear wheels 53, 54 independently of the brake pedal 2, the supply/discharge valves 63, 64 are controlled by the control device 100, and the wheel cylinders 53a, 5 are activated depending on the slip situation.
The brake fluid pressure of 4a is increased/decreased or maintained, and
Over-rotation will be suppressed and slips will be prevented.

In this embodiment, when the output hydraulic pressure of the hydraulic pressure booster 20 disappears due to loss of power hydraulic pressure of the power hydraulic pressure source 40, or when the output hydraulic pressure of the wheel cylinders 51a, 52a
If a liquid leak occurs on the side, the first and third switching valves 65, 67 and the on-off valve 60 work together to ensure braking force and function effectively as a fail-safe.

That is, in the former case, when the hydraulic pressure sensor 40a detects that the power hydraulic pressure has become lower than the predetermined pressure, the control device 100 returns the on-off valve 60 to the closed position, and at the same time, the first switching valve 65 is turned on. It is inactive, that is, in a normal state, and the third switching valve 6
7 is also inactive. Therefore, braking is performed by the operation of the tandem master cylinder 10 for both the front and rear wheels.

In the latter case, when the brake fluid in the reservoir 41 decreases due to a fluid leak, the fluid level sensor 41a detects a decrease in the brake fluid, or when a decrease in the power fluid pressure of the power fluid pressure source 40 is detected by the fluid pressure sensor 40a, the control device 100 detects a decrease in the brake fluid in the reservoir 41. The on-off valve 60 is returned to the closed position. At this time, if anti-lock control is in progress, it is stopped, and the first to third switching valves 65 to 67 are inactivated, resulting in the positions shown in FIG. 4. Therefore, the first pressure chamber 12 is provided in the wheel cylinders 53a and 54a.
The brake force is ensured by the brake fluid pressure from the on-off valve 60 to prevent fluid leakage from the wheel cylinders 51a and 52a.
The output hydraulic pressure of the hydraulic pressure booster 20 is shut off by the on-off valve 60 and the first and third switching valves 65 and 67, so that outflow is prevented, thus maintaining the boost operation for the tandem master cylinder 10. .

In the above embodiment, the hydraulic booster 20 is used as the dynamic hydraulic pressure control device according to the present invention, but for example, a negative pressure booster is used as the booster, and the spool valve 28 of the hydraulic booster 20 is included. A pressure regulating mechanism will be installed separately, and this will be installed in tandem master cylinder 1.
It may also be connected to the second liquid supply chamber 17 of No. 0.

[Effects of the Invention] As described above, according to the present invention, when the normally closed valve device is driven,
When the brake pedal is actuated, the output hydraulic pressure of the dynamic hydraulic pressure control device is supplied to the second fluid supply chamber of the second piston of the tandem master cylinder, thereby increasing the brake pedal stroke with respect to the system communicating with the second pressure chamber. be shortened.

Since a normally closed valve device is provided in the hydraulic pressure path from the dynamic hydraulic pressure control device to the second fluid supply chamber, the normally closed valve device returns to its normal state, that is, the closed position, when the vehicle stops, etc. The hydraulic path is blocked. Therefore, even when the vehicle is stopped, it is possible to reliably prevent brake fluid from flowing out from the dynamic hydraulic pressure control device to the wheel cylinders via the hydraulic pressure path.

By configuring the normally-closed valve device to control the valve means in response to the start switch of the vehicle engine, the normally-closed valve device opens and closes in conjunction with the start switch, thereby achieving the above-mentioned stroke shortening function when the engine starts. Therefore, the hydraulic pressure path can be reliably shut off in response to engine stoppage.

Furthermore, if the brake operation detection means is provided and the valve means is configured to be driven only when the start switch is turned on to the engine starting side when the brake is not activated, the valve means is activated from the dynamic hydraulic pressure control device. Reaction to the brake pedal when brake fluid pressure is supplied to the second fluid supply chamber is prevented, and so-called kickback can be prevented.

Additionally, in addition to the above, if the device is equipped with a hydraulic pressure detecting means and a liquid amount detecting means, and has only a small number of control means including a means for driving a valve means in accordance with these detection signals, dynamic hydraulic pressure control may be used. Even if a fluid leak occurs in a wheel cylinder connected to the device, the outflow of brake fluid is reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the hydraulic brake device of the present invention, FIG. 2 is a circuit diagram of a control circuit of the same embodiment, and FIG. 3 is a circuit diagram of another embodiment of the control circuit. FIG. 4 is an overall configuration diagram showing another embodiment of the hydraulic brake device of the present invention. 2...Brake pedal. 2a... Brake sensor (brake operation detection means) 1
0...Tandem master cylinder. 11...First piston. 12...First pressure chamber. 13...First liquid supply chamber. 14a, 18a... Valve body. 15...Second piston. 16...Second pressure chamber. 17...Second liquid supply chamber. 20... Hydraulic pressure booster (dynamic hydraulic pressure control device). 40...Power hydraulic pressure source. 41...Reservoir. 40a...hydraulic pressure sensor (hydraulic pressure detection means). 41a...Liquid amount sensor (liquid amount detection means). 51a-54a...Wheel cylinder. 60... Open/close valve (normally closed valve device, valve means) 61 to 64.
・・Supply/discharge valve. 65-67...Switching valve. 71 to 79...first hydraulic pressure path to ninth hydraulic pressure path. 90...Control circuit (control means). 100...Control device (control means) Patent applicant Aisin Seiki Co., Ltd. Toyota Motor Corporation

Claims (4)

[Claims] (1) A reservoir for storing brake fluid, a first piston that slides in a cylinder hole bored in the housing in response to a brake pedal, and a second piston that slides in response to the first piston to control the cylinder. A first pressure chamber, a second pressure chamber, a first fluid supply chamber, and a second fluid supply chamber are formed in the hole, and the brake fluid in the reservoir is supplied through the first fluid supply chamber and the second fluid supply chamber. a tandem master cylinder that is introduced into the first pressure chamber and the second pressure chamber and outputs brake fluid pressure by reducing it in accordance with the sliding of the first piston and the second piston, respectively; and a tandem master cylinder that increases the pressure of the brake fluid to a predetermined pressure. a power hydraulic pressure source that outputs power hydraulic pressure, and a dynamic hydraulic pressure control device that inputs the power hydraulic pressure outputted from the power hydraulic pressure source and outputs a regulated brake hydraulic pressure in response to the brake pedal. The first pressure chamber and the second pressure chamber of the tandem master cylinder are communicatively connected to a wheel cylinder mounted on each wheel of the vehicle, and the second fluid supply chamber of the tandem master cylinder is connected to the dynamic hydraulic pressure control device. The hydraulic brake device is characterized in that a normally-closed valve device is interposed in a hydraulic path that communicates the second fluid supply chamber and the dynamic hydraulic pressure control device. Device. (2) The normally closed valve device communicates the valve means that normally shuts off the hydraulic pressure path with the hydraulic pressure path when a start switch of an engine mounted on the vehicle is turned on to start the engine. 2. The hydraulic brake device according to claim 1, further comprising control means for driving said valve means. (3) A brake operation detection means is provided for detecting the operation state of the brakes of the vehicle, and when the control means detects that the brake operation detection means detects that the brake is not activated and the start switch is turned on to start the engine. 3. The hydraulic brake device according to claim 2, further comprising means for driving said valve means and controlling the hydraulic pressure path to communicate with each other. (4) A hydraulic pressure detecting means for detecting the output power hydraulic pressure of the power hydraulic pressure source, and a fluid volume detecting means for detecting the brake fluid amount in the reservoir, and the control means is configured to control the fluid volume detecting means. and the detection signal of the hydraulic pressure detection means is input, and at least one of: when the output power hydraulic pressure of the power hydraulic pressure source is below a predetermined pressure, and when the amount of brake fluid in the reservoir is below a predetermined amount. 4. The hydraulic brake device according to claim 2, further comprising means for controlling driving of said valve means at one time.