JP2000318597A - Hydraulic pressure source circuit in hydraulic booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve the responsiveness of a hydraulic booster without making a system large-sized. SOLUTION: With the operation start of a hydraulic booster, a pump 22 is operated, and pump delivery pressure is introduced into a power chamber 6. At the same time, a discharge valve 14 is closed by the advance of an input shaft 7, while a supply valve 19 is opened. The power chamber 6 is thereby cut off from a resevoir 23 for the hydraulic booster 2 and connected to an accumulator pressure introducing port 16, and accumulator pressure is supplied to the power chamber 6. In the initial stage of operation, a power piston 5 is rapidly actuated mainly by the accumulator pressure higher than the comparatively low pump delivery pressure, and the hydraulic booster 2 is rapidly actuated. When the pump delivery pressure becomes high, the power piston 5 is rapidly actuated mainly by high pump delivery pressure. Responsiveness of the hydraulic booster 2 is thereby improved. Since the accumulator pressure is complementarily used, an accumulator 24 can be small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects an operation of an operating means, activates a hydraulic pressure source by a detection signal, and controls the operating force of the operating means to a predetermined magnitude by the hydraulic pressure from the hydraulic pressure source. It belongs to the technical field of hydraulic booster that outputs by boosting, especially,
The invention belongs to the technical field of a hydraulic pressure source circuit of a hydraulic booster capable of improving the response at the start of operation.

[0002]

2. Description of the Related Art A brake hydraulic booster system conventionally used in an automobile is provided with a hydraulic booster that boosts the pedal depression force of a brake pedal to a predetermined magnitude and outputs the boosted hydraulic pressure. By operating the brake master cylinder with a large output of the hydraulic pressure booster to generate a master cylinder pressure, a large brake force is obtained with a small brake pedal depression force. In such a hydraulic booster, the input shaft generally strokes when the brake pedal is depressed, and the control valve is switched by the stroke of the input shaft, so that the hydraulic pressure from the hydraulic pressure source is introduced into the power chamber. By operating the power piston with the introduced hydraulic pressure, a large output is generated.

[0003]

In the hydraulic booster employed in such a conventional brake hydraulic booster, when a hydraulic pressure source for generating hydraulic pressure is constituted by a pump, In order to improve the response at the start of operation, it is necessary to always operate the pump. However, if the pump is constantly operated, not only will a large amount of energy be consumed, but also the durability of the pump will be a problem.

Therefore, it is conceivable to operate the pump only when the brake pedal is depressed. However, since the pump discharge pressure immediately after the start of operation of the pump is low, the output start of the hydraulic booster is delayed accordingly. . This delay in the output of the hydraulic booster causes no particular problem in the brake operation, but it is desirable that the output start of the hydraulic booster after the brake pedal is depressed be earlier. In particular, when the brake is operated quickly, such as during a sudden braking operation, it is desirable that the output start of the hydraulic booster be as early as possible. That is, it is desired to improve the responsiveness of the hydraulic booster as much as possible.

In some cases, an accumulator is used as a hydraulic pressure source in a conventional brake hydraulic booster system.
This hydraulic pressure source always stores a predetermined pressure by a pump in an accumulator, switches a control valve by depressing a brake pedal, and supplies the accumulator pressure to a hydraulic booster. If this accumulator is used, the accumulator pressure is high beforehand, so that the hydraulic booster starts operating immediately after switching of the control valve by depressing the brake pedal, and the hydraulic booster Responsiveness can be further improved.

However, if only the accumulator pressure is used to operate the hydraulic booster, the capacity of the accumulator needs to be increased, and the accumulator inevitably becomes large. The accumulator of the conventional general brake hydraulic booster is about 200 to 300 cc,
It is quite large. Such a large accumulator requires a large mounting space, and the degree of freedom in mounting the accumulator is reduced. Thus, in the hydraulic pressure source of the conventional brake hydraulic booster system,
The demand for improving the responsiveness of the hydraulic booster as much as possible cannot always be sufficiently satisfied.

The present invention has been made in view of such circumstances, and has as its object to improve the responsiveness of a hydraulic booster without increasing the size of the system. It is to provide a hydraulic pressure source circuit in a pressure booster.

[0008]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a reservoir for storing a liquid, an operating member, and an input shaft operated by inputting an input by operating the operating member. A power piston that generates an output, a power chamber that is partitioned by the power piston, and into which a hydraulic pressure for operating the power piston is introduced, and that is operated and controlled by the input shaft, and when the power chamber is not operated, the power chamber is connected to the reservoir. And a control valve for controlling the hydraulic pressure of the power chamber in accordance with an input of the input shaft during operation, and a hydraulic pressure source circuit for supplying a hydraulic pressure introduced to the power chamber. In the hydraulic pressure booster, a pump that is activated when the operation member is operated to generate a pump discharge pressure includes a normally open on-off valve and a first check valve that allows only a flow of liquid from the pump. And it is connected to the power chamber,
Further, an accumulator in which accumulator pressure is stored is connectable to the power chamber via accumulator pressure supply control means for supplying the accumulator pressure to the power chamber when the input shaft operates. A pump and the accumulator are connected via a second check valve that allows only the flow of the liquid from the pump.

Further, according to a second aspect of the present invention, the accumulator pressure supply control means is actuated by a valve seat fixed to the power piston and the input shaft so that the accumulator pressure supply control means can be attached to and detached from the valve seat. It is a poppet type control valve comprising a valve or a valve body having a conical valve. Further, the invention according to claim 3 is characterized in that an accumulator pressure supply passage shutoff means for shutting off an accumulator pressure supply passage between the power chamber and the accumulator when the pump discharge pressure reaches a predetermined pressure. I have.

[0010]

In the hydraulic pressure source circuit of the hydraulic booster of the present invention having the above-described structure, when the operating member is operated, the pump operates to supply the pump discharge pressure to the power chamber. Then, the accumulator pressure supply control means operates to supply the accumulator pressure to the power chamber. This allows
In the early stage of operation, when the pump discharge pressure is relatively low after the pump operation starts, the accumulator pressure, which is a predetermined high pressure from the beginning, causes the hydraulic pressure in the power chamber to rise quickly, and the power piston operates more quickly and more reliably. I do. Thereby, the responsiveness and operational reliability of the hydraulic booster of the present invention are both further improved.

Further, in contrast to a conventional hydraulic booster equipped with an accumulator, in which all operations are performed by accumulator pressure, the hydraulic booster of the present invention supplements the pump discharge pressure at the beginning of operation. The accumulator can be much smaller than conventional hydraulic boosters. In particular, according to the third aspect of the present invention, the hydraulic pressure source circuit in the hydraulic booster of the present invention shuts off the accumulator pressure supply passage when the pump discharge pressure exceeds a predetermined pressure, and consumes the accumulator pressure only in the initial stage of operation. Therefore, the accumulator can be further reduced.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a brake hydraulic pressure generator to which an example of an embodiment of a hydraulic pressure source circuit in a hydraulic booster according to the present invention is applied. In the following description, “front” indicates the left side of each drawing and “rear” indicates the right side of each drawing. As shown in FIG. 1, in a brake hydraulic pressure generating device 1 in this example, a hydraulic booster 2 and a master cylinder 3 operated by an output of the hydraulic booster 2 are integrally connected. .

First, the hydraulic booster 2 will be described. A power piston 5 is fitted in an axial hole of the housing 4 in a liquid-tight and slidable manner. A power chamber 6 is defined between the rear end of the power piston 5 and the housing 4. An input shaft 7 is slidably fitted in an axial hole of the power piston 5, and a rear end of the input shaft 7 is connected to a brake pedal 8. The input shaft 7 has a first diameter increasing in order from the front end to the rear end.
Or a stepped shaft having fourth diameter portions 7a, 7b, 7c, 7d. The input shaft 7 communicates with a radial hole 7e opening on the outer periphery of the second radial portion 7b, a radial hole 7f opening on the outer periphery of the third radial portion 7c, and these radial holes 7e, 7f. An axial hole 7g is provided.

The reaction force piston 9 is connected to the power piston 5
Slidably fits in the axial hole of the input shaft 7 and is externally slidably fitted to the third and fourth diameter portions 7c and 7d of the input shaft 7 in a liquid-tight manner. The reaction force piston 9 extends through the housing 4 in a liquid-tight and slidable manner and extends to the outside of the housing 4. The force piston 9 is biased rearward.

Further, the reaction force piston 9 is always urged forward by the spring force of a reaction force control spring 10 contracted between the reaction force piston 9 and the power piston 5, so that the power When the fluid pressure in the chamber 6 is smaller than the predetermined pressure,
As shown, the front end of the reaction force piston 9 is the power piston 5
To come into contact with. When the fluid pressure in the power chamber 6 is equal to or higher than a predetermined pressure, the reaction force piston 9 moves rearward with respect to the input shaft 7 against the spring force of the reaction force control spring 10, and The portion 9a comes into contact with the step 7h of the input shaft 7. Further, the reaction force piston 9 is provided with a radial hole 9b for constantly connecting the power chamber 6 and the radial hole 7f of the input shaft 7.

A passage hole 5a is provided for connecting between an axial hole of the power piston 5 on which the input shaft slides and an outer peripheral surface of the power piston 5, and the passage hole 5a is provided between the outer peripheral surface of the power piston 5 and the passage hole 5a. An annular axial passage 11, which is formed by a gap between the inner peripheral surface of the housing 4 in the axial direction and a gap between an outer peripheral surface of a primary piston of the master cylinder 3 described later and an inner peripheral surface of the housing 4, is formed in the housing 4. It is always in communication with the master cylinder reservoir 13 through the discharge port 12.

Then, the second and third diameter portions 7 of the input shaft 7
The discharge valve 14 is constituted by the step between b and 7c and the passage hole 5a. In the illustrated non-operating state, the third diameter portions 7b, 7
c is located in the middle of the passage hole 5a and the discharge valve 14 is open, and at this time, the power chamber 6 is
b, a radial hole 7f, an axial hole 7g, a radial hole 7e, a gap between an outer peripheral surface of the second radial portion 7b of the input shaft 7 and an inner peripheral surface of the axial hole of the power piston 5, a passage hole 5a. , Axial passage 1
1 and the reservoir 13 for the master cylinder via the radial passage 4a. Further, the input shaft 7 moves forward relative to the power piston 5 and the third diameter portions 7b, 7c
When the stepped portion is removed from the passage hole 5a, the discharge valve 14 is closed and the power chamber 9 is shut off from the reservoir 13 for the master cylinder.

Further, the housing 4 is formed with a pump discharge pressure inlet 15 for introducing a discharge pressure from a pump described later and an accumulator pressure inlet 16 for introducing a hydraulic pressure accumulated in an accumulator described later. Have been. The pump discharge pressure introduction port 15 is always connected to the power chamber 6 via a passage hole 4b formed in the housing 4, and the accumulator pressure introduction port 16 is formed on the outer peripheral surface of the power piston 5. It is always connected to the axial hole 5d of the power piston 5 through the annular groove 5b and the passage hole 5c of the power piston 5.

The power piston 5 is provided with a valve element 17 having a conical valve 17a. In that case, the conical valve 17a
The valve body 17 is provided in the power piston 5 in a liquid-tight and slidable manner in a state where is disposed in the axial hole 5d. The conical valve 17a can be seated on a valve seat 5e provided on the power piston 5. The valve body 17 always has a conical valve 17a and a valve seat 5e due to the spring force of a valve spring 18.
The seat is biased in the seating direction. The conical valve 17a and the valve seat 5e constitute a supply valve 19 for supplying an accumulator pressure described later to the power chamber 6. The front end of the first diameter portion 7a of the input shaft 7 is in contact with the conical valve 17a of this valve body.

In the non-operating state shown in the drawing, the conical valve 17a is seated on the valve seat 5e and the supply valve 19 is closed, and at this time, the power chamber 6 is shut off from the accumulator pressure introduction port 16. When the conical valve 17a is separated from the valve seat 5e, the supply valve 19 is opened, and at this time, the power chamber 6 has the radial holes 9b, the radial holes 7f, the axial holes 7g, and the radial holes 7g.
e, a gap between the outer peripheral surface of the second diameter portion 7b of the input shaft 7 and the inner peripheral surface of the axial hole of the power piston 5, a gap between the conical valve 17a and the valve seat 5e, an axial hole 5d, It is connected to the accumulator pressure inlet 16 through the passage hole 5c and the annular groove 5b.

Further, the pump discharge pressure inlet 15 is connected to the discharge side of a pump 22 via a check valve 20 and a normally-open solenoid valve 21. This pump 22
When the brake pedal is depressed, the depression of the pedal is detected by a detection sensor (not shown) such as a pedal depression force detection sensor or a stroke detection sensor of the input shaft 7, and the operation is performed to suck the liquid in the reservoir 23 for the hydraulic booster. In addition to discharging, the operation is stopped by releasing the brake pedal.

The accumulator pressure introduction port 16 is connected to an accumulator 24, and the accumulator 24 is connected to the discharge side of the pump 22 via a check valve 25. Although not shown, pressure detecting means such as a pressure switch or a pressure sensor for detecting the accumulator pressure is provided, and when the accumulator pressure becomes lower than the first predetermined pressure based on the pressure detection signal of the pressure detecting means. , The solenoid on-off valve 21 is closed and the pump 22
Is operated, the accumulator pressure stored in the accumulator 24 is increased, and the accumulator pressure becomes the first accumulator pressure.
When the pressure rises to the second predetermined pressure higher than the predetermined pressure, the pump 2
2 is stopped and the solenoid on-off valve 21 is opened. In this manner, the accumulator 24 normally stores a predetermined accumulator pressure. The accumulation of pressure in the accumulator 24 may not be performed, for example, while the vehicle is running or when the brake is operated. The supply valve 19, the normally open electromagnetic on-off valve 21, the pump 22, the reservoir 23 for the hydraulic booster, the accumulator 24, and the two check valves 20 and 25 are used to supply a hydraulic pressure in the hydraulic booster of this example. The circuit is configured.

On the other hand, the master cylinder 3 will be described. The master cylinder 3 is configured as a tandem master cylinder having a primary piston 26 and a secondary piston 27 having the same effective pressure receiving area. The primary piston 26 is formed integrally with the power piston 5 of the hydraulic booster 2, and slides in an axial hole of the housing 4 in a liquid-tight manner by a seal member 28 such as a cup seal provided in the housing 4. It is movably provided. The secondary piston 27 is also provided in the axial hole of the housing 4 in a liquid-tight and slidable manner by a seal member 29 such as a cup seal provided in the housing 4.

A primary chamber 30 is formed between the primary piston 26 and the secondary piston 27, and a primary return spring 31 is contracted. The housing 4 and the secondary piston 2
7, a secondary chamber 32 is formed, and a secondary return spring 33 is contracted. In that case, the spring force of the secondary return spring 33 is set to be larger than the spring force of the primary return spring 31.

A radial hole 34 is formed at the front end of the primary piston 26, and this radial hole 34 can communicate with the master cylinder reservoir 13 through the discharge port 12. In the illustrated inoperative position of the primary piston 26, the radial hole 34 is located slightly behind the seal member 28. At this time, the primary chamber 30 communicates with the master cylinder reservoir 13. When the radial hole 34 is positioned forward of the seal member 28 by moving forward, the primary chamber 30 and the reservoir 13 for the master cylinder are shut off, and a master cylinder pressure is generated in the primary chamber 30.

A radial hole 35 is formed at the front end of the secondary piston 27. The radial hole 35 can communicate with the master cylinder reservoir 13 through a passage hole 36 of the housing 4. I have. In the illustrated inoperative position of the secondary piston 27, the radial hole 35 is located slightly behind the seal member 29, and at this time, the secondary chamber 32 communicates with the master cylinder reservoir 13. Advance to radial hole 35
Is located forward of the seal member 29, the secondary chamber 32 and the reservoir 13 for the master cylinder are shut off, and a master cylinder pressure is generated in the secondary chamber 32.

The primary chamber 30 is connected to a wheel cylinder of one of the two brake systems via a primary output port 36 formed in the housing 4, and the secondary chamber 32 is formed in the housing 4. It is connected to a wheel cylinder (not shown) of the other of the two brake systems via a secondary output port 37 provided. Note that the reservoir 23 for the hydraulic booster can also be used as the reservoir 13 for the master cylinder.

Next, the operation of the thus constructed brake fluid pressure generating device 1 of this embodiment will be described. When the brake is not operated when the brake pedal is not depressed, the pump 22 is stopped, and the accumulator 24 stores a pressure equal to or higher than a predetermined pressure. Further, the power piston 5, the input shaft 7, the reaction force piston 9, the primary piston 26 and the secondary piston 27 are all in the inoperative positions shown in the drawing, the supply valve 19 is closed, and the discharge valve 14 is open. Further, the solenoid on-off valve 21 is also open. Accordingly, neither the pump discharge pressure nor the accumulator pressure is supplied to the power chamber 6, and no master cylinder pressure is generated in the primary chamber 30 and the secondary chamber 32.

When the brake operation is performed by depressing the brake pedal, the depression of the brake pedal is detected, the pump 22 starts operating, and the hydraulic pressure due to the discharge pressure of the pump 22 is introduced into the power chamber 6. At the same time, the input shaft 7 moves forward, so that the discharge valve 14 is closed and the valve element 17 is
And the feed valve 19 moves forward, and the supply valve 19 is opened. This shuts off the power chamber 6 from the master cylinder reservoir 13,
Since it is connected to the accumulator 24, the accumulator pressure is also introduced into the power chamber 6.

Then, the hydraulic piston introduced into the power chamber 6 causes the power piston 5 to advance, so that the hydraulic booster 2
Operates and outputs. At the start of the operation of the hydraulic pressure booster 2, since the pump discharge pressure is not so high, the power piston 5 moves forward mainly due to the relatively high accumulator pressure introduced from the accumulator 24. Therefore, the hydraulic booster 2 starts to operate quickly and outputs, and the delay at the start of operation is reduced. At this time, since the accumulator pressure is higher than the pump discharge pressure, the accumulator pressure introduced into the power chamber 6 tends to flow out of the pump pressure inlet 15 toward the pump 22, but is blocked by the check valve 20. You. Therefore, the accumulator pressure acts on the power piston 5 without loss.

When the power piston 5 advances, the primary piston 26 advances and its radial hole 34
8 and a master cylinder pressure is generated in the primary chamber 30. Further, due to the master cylinder pressure generated in the primary chamber 30, the secondary piston 27 advances, the radial hole 35 passes through the cup seal 56, and the master cylinder pressure is also generated in the secondary chamber 32. Each master cylinder pressure generated in the primary chamber 30 and the secondary chamber 32 is introduced from the primary output port 36 and the secondary output port 37 to each wheel cylinder of each system. At this time, as described above, both pistons 26, 27
Are set to be equal to each other, the master cylinder pressures of the primary chamber 30 and the secondary chamber 32 are the same, and the same hydraulic pressure is supplied to each wheel cylinder. The brake pressures of the brake systems are equal.

In the initial stage of operation in which each wheel cylinder does not generate a braking force due to the loss stroke of each wheel cylinder or the like, the hydraulic pressure in the power chamber 6 is not so high yet, and the reaction force piston 9 is driven by the reaction force control spring. It does not retreat against the spring force of 10 and does not reach the point where the step 9a of the reaction force piston 9 contacts the step 7h of the input shaft 7. Thus, the step 9a of the reaction force piston 9 is
Of the input shaft 7 is hardly affected by the reaction force piston 9. Therefore, in the early stage of the operation, the hydraulic booster 2 performs a so-called jumping action.

When the hydraulic pressure in the power chamber 6 further rises and the power piston 5 further moves forward and the loss stroke of each wheel cylinder is eliminated, each wheel cylinder generates a braking force, and substantially, two brake systems are used. The brakes are activated. In this state, the raised hydraulic pressure in the power chamber 6 is a predetermined pressure, and the hydraulic pressure causes the reaction force piston 9 to retreat against the spring force of the reaction force control spring 10. Then, the step 9a of the reaction force piston 9 comes into contact with the step 7h of the input shaft 7, and the reaction force piston 9 applies a reaction force to the input shaft 7 by the urging force of the hydraulic pressure in the power chamber 6 so that the input force of the input shaft 7 is input. And the jumping action ends.

When the power piston 5 moves forward, the conical valve 1
When 7a is seated on the valve seat 5e and the supply valve 19 is closed, the power chamber 6 is shut off from the accumulator 24. During this time, the discharge pressure from the pump # 22 continues to be introduced into the power chamber 6, and the fluid pressure in the power chamber 6 increases. Then, the power piston 5 advances slightly and the discharge valve 14 opens slightly. Then, the discharge liquid of the pump 22 introduced into the power chamber 6 is discharged to the master cylinder reservoir 13 while being throttled to the clearance of the discharge valve 14, and the hydraulic pressure generated in the power chamber 6 is applied to the input shaft 7. Since it acts as a reaction force, the clearance of the discharge valve 14 is controlled according to the input of the input shaft 7, and the hydraulic pressure of the power chamber 6 is controlled to a pressure corresponding to the input of the input shaft 7.

When the input of the input shaft 7 further increases, the input shaft 7 moves forward with respect to the power piston 5, and the clearance of the discharge valve 14 further decreases, so that the hydraulic pressure in the power chamber 6 further increases and the input shaft 7 7 is controlled to a pressure corresponding to the increased input. Thus, as the input pressure of the input shaft 7 increases, the hydraulic pressure in the power chamber 6 continuously increases at a predetermined boosting ratio with respect to the input by the pump discharge pressure and the accumulator pressure,
The hydraulic booster 2 boosts the input of the input shaft 7 at this boost ratio and outputs it.

The primary chamber 30 and the secondary chamber 3 of the master cylinder 3 are output from the hydraulic booster 2.
2 is supplied to the wheel cylinders of the respective systems, so that the wheel cylinders of the respective systems have a large braking force boosted with respect to the input of the input shaft 7 at a normal boosting ratio. Is generated, and the brake is operated with this braking force.

When the brake pedal is released to release the brake operation, first, both the input shaft 7 and the reaction force piston 9 are retracted with respect to the power piston 5.
Then, since the clearance of the discharge valve 14 is greatly opened, the hydraulic pressure in the power chamber 6 is quickly discharged to the master cylinder reservoir 13, and the hydraulic pressure in the power chamber 6 is rapidly reduced. At the same time, the pump 22 is stopped.

Accordingly, the primary piston 26, the secondary piston 27, and the power piston 5 are all retreated quickly by the master cylinder pressure in the secondary chamber 32 and the spring force of the secondary return spring 33. When the secondary piston 27 retreats, the radial hole 35 passes through the seal member 29 and is located again behind the seal member 29, so that the secondary chamber 32 communicates with the master cylinder reservoir 13 again. Therefore, the pressure fluid of the wheel cylinder of the other system is quickly discharged to the master cylinder reservoir 13 through the secondary chamber 32. Furthermore,
With the master cylinder pressure of the primary chamber 30 and the spring force of the primary return spring 31, the primary piston 26 and the power piston 5 are further retreated.
When the primary piston 26 retreats, the radial hole 34 passes through the seal member 28 and is located again behind the seal member 28, so that the primary chamber 30 communicates with the master cylinder reservoir 13 again. For this reason, the pressure fluid of one wheel cylinder is also quickly discharged to the master cylinder reservoir 13 through the primary chamber 30. As a result, the brakes of both brake systems are quickly released.

When the hydraulic pressure in the power chamber 6 drops to a predetermined pressure,
The reaction force piston 9 is generated by the spring force of the reaction force control spring 10.
Is relatively advanced with respect to the power piston 5 and the input shaft 7 and contacts the power piston 5, and the step 9 a of the reaction force piston 9 is separated from the step 7 h of the input shaft 7.

When the power piston 5 is at the non-operating position shown, both the reaction force piston 9 and the input shaft 7 are at the non-operating position shown, and the primary piston 26 and the secondary piston 27 are also at the non-operating position shown.
As a result, the hydraulic booster 2 stops outputting, the master cylinder 3 loses its master cylinder pressure, and the brake is completely released. Thus, the brake fluid pressure generating device 1 enters the non-operation state shown in FIG.

When the pump 22 is out of order and the pump discharge pressure is not introduced into the power chamber 6 when the brake pedal is depressed and the brake pedal is depressed, the input shaft 7 advances greatly, and the front end of the input shaft 7 contacts the power piston 5. Therefore, the input shaft 7 is connected to the primary piston 26 via the power piston 5.
, So that the primary piston 26 moves forward. At this time, since the supply valve 19 is opened, if the accumulator pressure is stored in the accumulator 24, the accumulator pressure is supplied to the power chamber 6. Therefore, the pedal depression force is boosted and the primary piston 26 is pressed.

As a result, the radial hole 34 advances forward from the seal member 28 to generate a master cylinder pressure in the primary chamber 30 as described above, and the secondary cylinder 2
7 advances, the radial hole 35 advances forward of the seal member 29, and a master cylinder pressure is generated in the secondary chamber 32. The primary chamber 30 and the secondary chamber 3 are provided in the same manner as in the normal state of the pump 22 described above.
2 master cylinder pressure is the primary output port 3
6 and the secondary output port 37 are supplied to each wheel cylinder of the two-brake system to operate the brake of the two-brake system. In this way, even when the pump 22 fails, the brake operation of the two-brake system is reliably performed.

As described above, according to the hydraulic pressure source circuit of the hydraulic booster 2 of this embodiment, in the initial stage of operation when the pump discharge pressure is low after the start of operation, the power piston 5 is operated mainly by the accumulator pressure. When the pump discharge pressure reaches a predetermined pressure, the pump discharge pressure is thereafter mainly operated by the power piston 5, so that the hydraulic booster 2 can output the pump pressure immediately after the start of operation. As a result, the responsiveness of the hydraulic booster 2 in the initial stage of operation is effectively improved.

Moreover, in contrast to the case where all the operations are performed by the accumulator pressure as in the conventional hydraulic booster equipped with an accumulator, the hydraulic booster 2 of this embodiment increases the pump discharge pressure in the early stage of operation. The accumulator can be much smaller than conventional accumulators because it only needs to be supplemented.

FIG. 2 is a view similar to FIG. 1 and schematically shows a brake fluid pressure generator to which another embodiment of the present invention is applied. The same components as those in the above-described example are denoted by the same reference numerals, and detailed description thereof will be omitted. In the hydraulic pressure source circuit of the hydraulic booster 2 of the above-described example, while the hydraulic pressure in the power chamber 6 is lower than the accumulator pressure, if the supply valve 19 is opened by the advancement of the input shaft 7, the accumulator pressure is constantly increased. The accumulator pressure is introduced into the chamber 6 and the consumption of the accumulator pressure is large. However, in the hydraulic pressure source circuit in the hydraulic booster 2 of this example, the accumulator pressure is reduced to a predetermined pressure by the hydraulic pressure of the power chamber 6 at the initial stage of operation. When the pump discharge pressure is smaller than the accumulator pressure and is equal to or higher than a predetermined pressure, the accumulator pressure is not introduced into the power chamber 6 even when the supply valve 19 is opened.

That is, in the hydraulic pressure source circuit in the hydraulic booster 2 of this example, an accumulator pressure supply passage shutoff valve 38 is provided in the accumulator pressure supply passage between the accumulator pressure introduction port 16 and the accumulator 24. Have been. The accumulator pressure supply passage cutoff valve 38 has a control piston 38c having an annular groove 38a formed on the outer peripheral surface thereof, a pump discharge pressure acting on one end, and a spring force of a spring 38b always acting on the other end. . When the pump discharge pressure is lower than a predetermined pressure, the control piston 38c is set to the rightmost position shown in the drawing by the spring force of the spring 38b. At this time, the accumulator pressure supply passage between the accumulator pressure inlet 16 and the accumulator 24 is communicated by the annular groove 38a, and the accumulator 2
The accumulator pressure of No. 4 is supplied to the accumulator pressure introduction port 16. The control piston 38
When the pump discharge pressure is equal to or higher than a predetermined pressure, the stroke c moves rightward against the spring force of the spring 38b at the pump discharge pressure. At this time, since the annular groove 38a is disconnected from the accumulator pressure supply passage connecting the accumulator pressure introduction port 16 and the accumulator 24, the accumulator pressure supply passage is shut off, and the supply of the accumulator pressure to the accumulator pressure introduction port 16 is stopped. It is supposed to be. Other configurations of the brake fluid pressure generating device 1 of this example are the same as those of the above-described example.

In the brake fluid pressure generating device 1 of this embodiment constructed as described above, since the pump discharge pressure is lower than the predetermined pressure at the beginning of operation, the accumulator pressure supply passage shut-off valve 38 is in the non-operating state shown in FIG. An accumulator pressure supply passage between the pressure introduction port 16 and the accumulator 24 is connected by an annular groove 38a. Therefore, in this state at the beginning of the operation, the discharge valve 14 is closed and the supply valve 19 is opened as in the above-described example, so that both the pump discharge pressure and the accumulator pressure are introduced into the power chamber 6. Then, the hydraulic pressure in the power chamber 6 substantially generates a braking force,
When the pressure at which the reaction force piston 9 is operated is reached, the pump discharge pressure is also a predetermined pressure, and is a pressure at which the control piston 38c of the accumulator pressure supply passage shutoff valve 38 is operated against the spring force of the spring 38b. Then, the control piston 38c strokes, and the annular groove 38a is disengaged from the passage connecting the accumulator pressure introduction port 16 and the accumulator 24, and this passage is cut off. As a result, the accumulator pressure is not introduced into the power chamber 6, only the pump discharge pressure is introduced into the power chamber 6, and the hydraulic pressure in the power chamber 6 is increased by only the pump discharge pressure.

As described above, when the pump discharge pressure reaches the predetermined pressure, the introduction of the accumulator pressure into the power chamber 6 is stopped, and only the accumulator pressure is consumed only at the beginning of operation, so that the accumulated pressure of the accumulator 24 is reduced. It does not consume much more than necessary and does not drop significantly in a short period of time, and the accumulator can be made even smaller. Therefore, the system does not become large.
Further, even when the hydraulic booster 2 is operating, if the pump discharge pressure is higher than the accumulated pressure of the accumulator 24, the pump discharge pressure is also supplied to the accumulator 24, and the accumulator 24 is maintained at a predetermined accumulator pressure.

On the other hand, when the brake pedal is released to release the brake, the pump 22 stops in the same manner as in the above-described example, so that the pump discharge pressure disappears, and the control piston 38c of the accumulator pressure supply passage shutoff valve 38 is turned off. Spring 3
Stroke to the left inoperative position by the spring force of 8b,
The annular groove 38a again connects the passage connecting the accumulator pressure introduction port 16 and the accumulator 24. Other functions and effects of the brake fluid pressure generating device 1 of this example are the same as those of the above-described example.

In the hydraulic pressure source circuit of the hydraulic booster 2 of each of the above-described examples, the accumulator pressure supply passage shutoff valve 3
The accumulator pressure supply passage shut-off valve 38 is formed by a normally open electromagnetic on-off valve, and the pump discharge pressure is detected by a pressure detecting means such as a pressure switch or a pressure sensor. The electromagnetic opening / closing valve may be opened when the pump discharge pressure is lower than a predetermined pressure based on the detection signal, and may be closed when the pump discharge pressure is higher than the predetermined pressure. .

In the hydraulic booster 2 of each of the above examples,
Although the jumping characteristic is provided by the reaction force piston 9, the hydraulic booster of the present invention employs the reaction force piston 9.
Is not always necessary and can be omitted. Further, the hydraulic pressure source circuit in the hydraulic booster of the present invention can be applied to other hydraulic systems other than the brake system.

[0052]

As is apparent from the above description, according to the hydraulic pressure source circuit in the hydraulic booster of the present invention, the hydraulic pressure in the power chamber is rapidly increased by the accumulator pressure at the beginning of operation. Therefore, the power piston can be operated more quickly and more reliably. Thereby, the responsiveness and operation reliability of the hydraulic booster can both be further improved.

Moreover, in contrast to a conventional hydraulic booster equipped with an accumulator, in which all of the operation is performed by accumulator pressure, the hydraulic booster of the present invention supplements the pump discharge pressure at the beginning of operation. The accumulator can be made smaller as compared with the conventional hydraulic booster. This allows the hydraulic system to be compact. In particular, according to the third aspect of the invention, when the pump discharge pressure becomes equal to or higher than the predetermined pressure, the accumulator pressure supply passage is shut off, and only the accumulator pressure is consumed only in the initial operation, so that the accumulator can be further reduced. .

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a brake hydraulic pressure generator to which an example of an embodiment of a hydraulic pressure source circuit in a hydraulic booster according to the present invention is applied.

FIG. 2 is a view similar to FIG. 1, schematically showing a brake fluid pressure generating device to which another example of the embodiment of the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Brake hydraulic booster, 2 ... Hydraulic booster, 3 ... Master cylinder, 4 ... Housing, 5 ... Power piston,
6 power chamber, 7 input shaft, 9 reaction force piston, 14 discharge valve, 19 supply valve, 20, 25 check valve, 2
DESCRIPTION OF SYMBOLS 1 ... Electromagnetic on-off valve, 22 ... Pump, 23 ... Reservoir for hydraulic booster, 24 ... Accumulator

Claims (3)

[Claims] 1. A reservoir for storing a liquid, an operating member, an input shaft operated by inputting an input by operating the operating member, a power piston for generating an output, and a power piston defined by the power piston. A power chamber into which a hydraulic pressure for operating the power chamber is introduced, the operation of which is controlled by the input shaft, the non-operating power chamber is connected to the reservoir, and the non-operating power chamber is operated in response to an input of the input shaft. In a hydraulic booster including a control valve for controlling a hydraulic pressure and a hydraulic pressure source circuit for supplying a hydraulic pressure introduced into the power chamber, the hydraulic pressure booster is operated when the operating member is operated to reduce a pump discharge pressure. The pump that is generated is connected to the power chamber via a normally open on-off valve and a first check valve that allows only the flow of liquid from the pump, and the accumulator pressure is stored. The accumulator is connected to the power chamber via accumulator pressure supply control means for supplying the accumulator pressure to the power chamber when the input shaft is operated, and the pump and the accumulator are connected to each other. A hydraulic pressure source circuit in the hydraulic booster, wherein the hydraulic pressure source circuit is connected via a second check valve that allows only the flow of the liquid from the pump. 2. The accumulator pressure supply control means includes:
It is a poppet type control valve comprising a valve seat fixed to the power piston and a valve body which is operated by the input shaft and has a ball valve or a conical valve which can be attached to and detached from the valve seat. The hydraulic pressure source circuit in the hydraulic booster according to claim 1. 3. An accumulator pressure supply passage shutoff means for shutting off an accumulator pressure supply passage between said power chamber and said accumulator when said pump discharge pressure reaches a predetermined pressure. Or a hydraulic pressure source circuit in the hydraulic booster according to 2.