JP2000318598A - Hydraulic pressure source circuit in hydraulic booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a system and to further improve the responsiveness of a hydraulic booster. SOLUTION: With brake operation, the operation of a pump 40 is started, and at the same time an input shaft 22 and a valve spool 26 move forward. Communication between an annular groove 26e and a radial hole 17d is thereby cut off, and a conical valve 73a is separated from a valve seat 17d to open a first hydraulic pressure supply valve. Pump pressure and accumulator pressure are thereby introduced into a power chamber 13 through the open first hydraulic pressure supply valve. Then a power piston 12 moves forward, and a hydraulic booster 2 is actuated to be output. When pump delivery pressure reaches a prescribed pressure, supply of accumulator pressure is stopped by an accumulator pressure supply passage cutoff valve 42. In addition, a diameter contracted part 32 is positioned in front of a sealing member 29 by the forward movement of the valve spool 26, and a second hydraulic pressure supply valve is opened. Pump pressure and accumulator pressure the introduced into the power chamber 13 through the second hydraulic pressure supply valve.

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, and the hydraulic pressure from the hydraulic pressure source is changed to the power chamber. When the power piston is operated by the introduced hydraulic pressure, a large output is generated.

[0004]

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.

[0006] 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 400-500cc,
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. In order to improve the responsiveness of the hydraulic booster, it is desired to simplify the system as much as possible.

The present invention has been made in view of such circumstances, and has as its object to provide a hydraulic booster which can simplify the system and further improve the responsiveness of the hydraulic booster. It is to provide a hydraulic source circuit in the device.

[0009]

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 provided in the housing in a liquid-tight and slidable manner and generating an output; a power chamber defined by a rear end of the power piston and into which a hydraulic pressure for operating the power piston is introduced; A control valve controlled by an input shaft to connect the power chamber to the reservoir when not in operation and to control the hydraulic pressure in the power chamber in response to input from the input shaft during operation; A hydraulic pressure booster having a hydraulic pressure source circuit for supplying a hydraulic pressure to be supplied, wherein a pump which is activated when the operating member is operated to generate a pump discharge pressure and an accumulator pressure are stored. An accumulator is connected to the power chamber via a normally closed first hydraulic pressure supply control valve that supplies the pump discharge pressure and the accumulator pressure to the power chamber when the input shaft operates. The pump is connected to the power chamber via a normally closed second hydraulic pressure supply control valve that supplies the pump discharge pressure and the accumulator pressure to the power chamber, and the second hydraulic pressure control valve is A power piston having a reduced diameter portion or a rear end provided at a rear end thereof, and a seal member provided in a power piston sliding hole of the housing for sliding the power piston in a liquid-tight manner. At the time of operation, the reduced diameter portion or the rear end is located rearward of the seal member so as to close to shut off the power chamber and the pump and the accumulator. The reduced diameter portion or the rear end over the piston is advanced is characterized in that said has a sealing member and the power chamber open on be located in front of the said pump and said accumulator so as to communicate.

The invention according to claim 2 is characterized in that when the pump discharge pressure becomes equal to or higher than a predetermined pressure, the accumulator is connected to the accumulator and the first and second hydraulic pressure supply control valves. A shut-off valve for shutting off the first and second hydraulic pressure supply control valves is provided.

[0011]

In the hydraulic pressure source circuit of the hydraulic booster according to the present invention having the above-described structure, when the operating member is operated, the first hydraulic pressure supply control valve is opened, and the pump discharge pressure and the accumulator are adjusted. Both pressures are supplied to the power chamber via the first hydraulic pressure supply control valve. Thus, in the initial stage of operation in which the pump discharge pressure is relatively low after the start of the pump operation, the hydraulic pressure in the power chamber rapidly rises due to the accumulator pressure that has been a predetermined high pressure from the beginning, and the power piston is more quickly and more Works reliably. Thereby, the responsiveness and operational reliability of the hydraulic booster of the present invention are both further improved. In this case, the pump is operated only when the hydraulic booster is operated, so that the durability of the pump is improved and the energy consumption is reduced.

In addition, a second hydraulic pressure supply control valve is provided at a rear end of the power piston or at a rear end of the power piston, and is provided in a power piston sliding hole of the housing to fluidly seal the power piston. And a sealing member that slides on the hydraulic pressure supply control valve. Thereby, the number of parts is reduced and the configuration of the system is simplified. Furthermore, the hydraulic booster of the present invention only needs to supplement the pump discharge pressure at the beginning of operation, as compared with the case where all of the operation is performed by the accumulator pressure as in the conventional hydraulic booster with an accumulator. Only the accumulator needs to be smaller than in the conventional hydraulic booster.

In particular, according to the invention of claim 2, in the hydraulic pressure source circuit of the hydraulic booster of the present invention, the accumulator pressure supply passage is shut off when the pump discharge pressure exceeds a predetermined pressure, and the accumulator pressure is supplied only at the beginning of operation. , The accumulator can be made even smaller.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a brake hydraulic pressure generator to which a first embodiment of a hydraulic pressure source circuit in a hydraulic booster according to the present invention is applied, and FIG. 2 is a hydraulic booster shown in FIG. 3 is a partially enlarged cross-sectional view of the master cylinder shown in FIG. 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 the brake hydraulic pressure generating device 1 in the first example, a hydraulic booster 2 and a master cylinder 3 operated by the output of the hydraulic booster 2 are integrated. It is connected to. In this case, an axial hole 5 opened at the right end and an axial hole formed continuously with the left end of the axial hole 5 and having a diameter smaller than the diameter of the axial hole 5 are formed in the housing 4 for the hydraulic booster. 6 are drilled respectively, and
An axial hole 7 is formed in the cap 47 of the master cylinder 3, an axial hole 8 is formed in the sleeve 46 of the master cylinder 3, and a master cylinder housing 45 is formed.
Is provided with an axial hole 9.

First, the hydraulic booster 2 will be described. As clearly shown in FIG. 2, a plug 10 is fitted in the axial holes 5 and 6, and in this case, the axial holes The right end of 6 is closed by a sealing member provided on the plug 10 in a liquid-tight manner. The plug 10 is fixed to the housing 4 by being brought into contact with the steps of the axial holes 5 and 6 by a nut 11 screwed to the housing 4 for the hydraulic booster.

A power piston 12 of the hydraulic booster 2 is disposed in the axial hole 6.
2 is a stepped piston having a large-diameter portion 12a on the rear side and a small-diameter portion 12b on the front side, and the large-diameter portion 12a is provided in the axial hole 6 and on the outer peripheral surface of the large-diameter portion 12a. And a seal member 29 provided in the hydraulic booster housing 4 in a liquid-tight and slidable manner. The rear end of the power piston 12 has a reduced diameter portion 3 having the same diameter as an annular groove 34 of the power piston 12 described later.
It is 2. When the power piston 12 is in the non-operating position shown in the drawing, the space between the inner peripheral surface of the axial hole 6 of the hydraulic booster housing 4 and the outer peripheral surface of the power piston 12 is made liquid-tight by the seal member 29. Although the annular groove 34 and the reduced diameter portion 32 are blocked, when the power piston 12 advances and the front end of the reduced diameter portion 32 comes before the seal member 29,
Liquid tightness by the seal member 29 between the inner peripheral surface of the axial hole 6 and the outer peripheral surface of the power piston 12 is eliminated, and the annular groove 3 is formed.
4 and the reduced diameter portion 32 communicate with each other.
Between the rear end of the power piston 12 and the plug 10,
A power chamber 13 is defined.

The power piston 12 has an axial hole 14 opened at the rear end of the power piston 12 and an axial hole formed in front of the axial hole 14 and having a diameter smaller than the diameter of the axial hole 14. 15 and an axial hole 16 formed further in front of the axial hole 15 and having a diameter smaller than the diameter of the axial hole 15, respectively. These axial holes 14, 15, 16 are It is formed as one stepped hole. Sleeves 17 are fitted in the axial holes 15 and 16 in a liquid-tight manner, and are fixed in the axial direction by cylindrical nuts 18. The sleeve 17 is provided with radial holes 17a, 17b, 17c penetrating from the outer peripheral surface to the inner peripheral surface. The radial holes 17a and 17b are always directly connected to the power chamber 13, and the radial holes 17c are always connected to the hydraulic booster reservoir 41 as described later. Furthermore,
At the front end of the sleeve 17, there is formed a valve seat 17d on which a conical valve to be described later attaches and detaches, and a radial groove 17e always connected to the radial hole 35 of the power piston 12 has a valve seat from the outer periphery of the sleeve. It is formed in a range that does not reach 17d.

A cylindrical reaction force piston 19 is loosely fitted in the axial hole 14 of the power piston 12 and is fitted to the rear end of the sleeve 17 in a liquid-tight and slidable manner. The rear portion of the reaction force piston penetrates the plug 10 in a liquid-tight and slidable manner and extends outside the hydraulic booster housing 4. A reaction force control spring 2 is provided between a flange portion 19 a formed at the tip of the reaction force piston 19 and a stop ring 20 attached to the power piston 12.
The reaction force piston 19 is constantly biased forward with respect to the power piston 12 by the spring force of the reaction force control spring 21. The front end of the reaction force piston 19 is in contact with the step 12 c at the front end of the axial hole 14 of the power piston 12. Also, the reaction force piston 1
A step 19b is formed in the inner hole 9.

As shown in FIG. 1, an input shaft 22 is slidably fitted into the reaction force piston 19, and the rear end of the input shaft 22 is connected to a brake pedal (not shown). ing. The input shaft 22 is formed as a stepped shaft having a step 22a having a small diameter at the front end.
The front end of the input shaft 22 is made liquid-tight by an O-ring 23. Also, the ring member 2 is attached to the front end of the input shaft 22.
4, the input shaft 22 moves rearward relative to the reaction force piston 19, and when the ring member 24 comes into contact with the reaction force piston 19, the input shaft 22 Is prevented from further retreating, and the retreating limit shown in the drawing is reached.

Further, a buffer member 25 such as an O-ring is provided on the step portion 22a of the input shaft 22, and the hydraulic booster 2
When the reaction force piston 19 moves backward relative to the input shaft 22 during the operation of the
b is in contact with the step 22a of the input shaft 22. In this case, the shock at the time of the contact is reduced by the buffer member 25, so that the sound generated by the contact is suppressed.

A valve spool 26 is slidably fitted to the sleeve 17.
A valve spring 27 contracted between the valve spool 26 and the sleeve 17 constantly urges the valve spring 27 rearward, and its rear end is in contact with the front end of the input shaft 22.

The valve spool 26 has an axial hole 26a extending axially at the center thereof and an axial hole 2a.
A radial hole 26b that constantly connects the rear end of the valve shaft 6a to the radial hole 17a of the sleeve 17, and a forward connection to the front of the valve spool 26 through the front end of the axial hole 26a and the outer periphery of the front end of the valve spool 26. A radial hole 26c, an axial hole 26d at a position eccentric from the center of the valve spool 26 and constantly communicating with a chamber 28 formed between the rear end of the sleeve 17 and the reaction force piston 19, and an outer peripheral surface. The annular groove 26e formed on the outer periphery of the portion of the valve spool 26 that supports one end of the valve spring 21
e and an axial groove 26f that constantly connects the radial hole 17c of the sleeve 17 to the sleeve 17 and a radial hole 26g that constantly connects the axial hole 26d to the annular groove 26e.

The radial hole 17b of the sleeve 17 and the annular groove 26e of the valve spool 26 are connected to each other with a relatively large passage area when the hydraulic booster 2 is not operated, and when the hydraulic booster 2 is operated. It is designed to be cut off while gradually reducing the area. The radial hole 1 of the sleeve 17
7c is an annular groove 12d formed in the power piston 12.
And a hydraulic booster housing 4 via an inclined axial hole 12e extending in the axial direction continuously to the annular groove 12d.
Is always connected to the space 23 between the inner peripheral surface of the axial hole 6 and the outer peripheral surface of the primary piston.

Further, the hydraulic booster housing 4 includes:
A hydraulic pressure inlet 30 into which a discharge pressure from a pump 40 described later and an accumulator pressure from an accumulator 43 are respectively introduced, and an outlet 31 from which a hydraulic fluid is discharged to a hydraulic booster reservoir 41 described later, respectively. Is formed.

Further, as shown in FIG. 1, the hydraulic pressure inlet 30 is always connected to the annular groove 34 of the power piston 12, and is connected to the discharge side of the pump 40 via a check valve 38. The pump 40 is operated by detecting the depression of the brake pedal when the brake pedal is depressed by a detection sensor (not shown) such as a pedal depression force detection sensor or a stroke detection sensor of the input shaft 22. Is sucked and discharged, and the operation is stopped by releasing the brake pedal. The hydraulic pressure inlet 30 is also connected to an accumulator 43 via an accumulator pressure supply passage shutoff valve 42, and the accumulator 43 is connected to a discharge side of the pump 40 via a check valve 44.

The accumulator pressure supply passage shutoff valve 42 is
An annular groove 42a is formed on the outer peripheral surface, and a control piston 42c to which a pump discharge pressure is applied at one end and a spring force of a spring 42b is always applied is provided at the other end. When the pump discharge pressure is equal to or lower than a predetermined pressure, the control piston 42c is set to the leftmost position shown in the drawing by the spring force of the spring 42b. At this time, the passage between the hydraulic pressure inlet 30 and the accumulator 43 is communicated by the annular groove 42a, so that the accumulator pressure of the accumulator 43 is supplied to the hydraulic pressure inlet 30. When the pump discharge pressure exceeds a predetermined pressure, the control piston 42c
With this pump discharge pressure, a stroke is made to the right against the spring force of the spring 42b. At this time, since the annular groove 42a is separated from the accumulator pressure supply passage connecting the hydraulic pressure inlet 30 and the accumulator 43, the accumulator pressure supply passage is shut off, and the supply of the accumulator pressure to the hydraulic pressure inlet 30 is stopped. It is supposed to be.

Although not shown, pressure detecting means such as a pressure switch and a pressure sensor for detecting the accumulator pressure are provided. Based on a pressure detection signal from the pressure detecting means, the accumulator pressure becomes lower than the first predetermined pressure and the brake pedal is turned on. When the pump 40 is not depressed, the accumulator pressure stored in the accumulator 43 is increased by operating the pump 40, and when the accumulator pressure increases to a second predetermined pressure higher than the first predetermined pressure, the pump 40 is stopped. Is done. Thus, the accumulator 43 normally stores a predetermined accumulator pressure.

Further, the discharge port 31 is always connected to the reservoir 41 for the hydraulic booster. Therefore, the radial hole 17c of the sleeve 17 is also formed by the annular groove 12d and the axial hole 12d.
e, is always connected to the hydraulic booster reservoir 41 through the space 23, the radial hole 36, and the discharge port 31 so that the pressure is equal to the atmospheric pressure.
6f, annular groove 26e, radial hole 26g and axial hole 2
The chamber 32 connected via 5d is also constantly connected to the reservoir 41 for the hydraulic booster and is kept at atmospheric pressure.

An axial hole 12f is formed in the power piston 12 at a position facing the front end of the valve spool 26 so as to always communicate with the radial groove 17e of the sleeve 17. In the axial direction 12f, a valve body 73 having a conical valve 73a formed at the rear end is slidably provided. The conical valve 73a can be attached to and detached from the valve seat 17d of the sleeve 17. In this case, the conical valve 73a is constantly urged by the spring force of the valve spring 74 in the direction of seating on the valve seat 17d. The front end of the valve spool 26 presses the conical valve 73 forward to be separated from the valve seat 17d. The radial groove 17 e of the sleeve 17 is provided with a radial hole 35 of the power piston 12.
And, it is always connected to the hydraulic pressure inlet 30 through the annular groove 34. Note that a ball valve can be used instead of the conical valve 73a.

As described above, the power chamber 13 is cut off from the pump 40 and the accumulator 43 when the power piston 12 and the valve spool 26 are not operated, while the radial hole 17b, the annular groove 26e, the axial groove 2
6f, radial hole 17c, annular groove 12d, axial hole 12
e, connected to the reservoir 41 for the hydraulic booster via the space 23, the radial hole 36, and the discharge port 31. When the valve spool 26 is operated, the conical valve 73a is pressed to be separated from the valve seat 17d. As a result, it is connected to the pump 40 and the accumulator 43 and is gradually disconnected from the reservoir 41 for the hydraulic booster. That is, the first control that controls the supply of the pump discharge pressure and the accumulator pressure to the power chamber 13 by the conical valve 73a and the valve seat 17d.
A hydraulic pressure supply control valve is formed, and the seal member 29 of the hydraulic booster housing 4 and the power piston 1
A second hydraulic pressure supply control valve for controlling the supply of the pump discharge pressure is constituted by the outer peripheral surface of the second hydraulic pressure control valve 2 and the reduced diameter portion 32 (to be described later, when the second hydraulic pressure supply control valve operates, the accumulator pressure is controlled). The introduction of the accumulator pressure is stopped by the supply passage shutoff valve 42, and only the pump discharge pressure is changed to the hydraulic pressure inlet 3
0), radial holes 17b in the sleeve 17
A discharge valve as a control valve for controlling the discharge of the hydraulic pressure in the power chamber 13 is constituted by the annular groove 26 e of the valve spool 26.

And first and second hydraulic pressure supply control valves,
The pump 40, the hydraulic booster reservoir 41, the accumulator 43, the two check valves 38 and 44, and the accumulator pressure supply passage shutoff valve 42 constitute a hydraulic pressure source circuit in the hydraulic booster of the first example. ing.

On the other hand, the master cylinder 3 will be described. As shown in FIGS. 1 and 3, the master cylinder 3 is provided with a cylindrical master cylinder housing 45 having a rear end opening. 4
A sleeve 46 is disposed inside the housing 5, and a cap 47 that supports the sleeve 46 in the axial direction between the sleeve 46 and the master cylinder housing 45 closes the rear end opening of the master cylinder housing 45. Is screwed into. The master cylinder 3 is configured as a tandem master cylinder having a primary piston 48 and a secondary piston 49 whose effective pressure receiving areas are set equal to each other.

As shown in FIGS. 1 and 3, the primary piston 48 is disposed in the axial hole 6 of the hydraulic booster housing 4, the axial hole 7 of the cap 47, and the axial hole 8 of the sleeve 46. Has been established. That is, a part of the primary piston 48 is disposed inside the hydraulic booster housing 4. The primary piston 48 is provided with a cup seal 50 provided in the hydraulic booster housing 4,
A cup seal 51 provided on the inner peripheral surface of the axial hole 7 of the cap 47, and a cup seal 52 provided between the sleeve 46 and the cap 47 so as to be liquid-tight and slidable. Is provided. The cup seal 52 prevents the flow of the liquid from the front side to the rear side and allows the reverse flow.

An axial hole 53 formed in the rear end of the primary piston 48 has a small diameter portion 1 of the power piston 12.
2b is loosely fitted. An adjusting member 54 is provided at the distal end of the small-diameter portion 12b of the power piston 12, and the adjusting member 54 is fitted with and fixed to a hole formed in the center of the distal end of the small-diameter portion 12b. And an elastic member 54b such as an O-ring or a rubber ring for preventing the cylindrical member 54a from falling out of the hole of the small-diameter portion 12b by being externally fitted to the cylindrical member 54a. The adjusting member 54 is in contact with the primary piston 48 to adjust the positions of the power piston 12, the primary piston 48 and the secondary piston 49.

The secondary piston 49 includes a sleeve 46
Axial hole 8 and master cylinder housing 45
Are disposed in the axial hole 9. The secondary piston 49 is provided between the sleeve 46 and the cup seal 55 provided on the inner peripheral surface of the axial hole 8 of the sleeve 46 and between the master cylinder housing 45 and the master cylinder housing 45. Seals 56 are provided in these holes 8 and 9 in a liquid-tight and slidable manner. The cup seal 56 prevents the flow of the liquid from the front side to the rear side and allows the reverse flow of the liquid.

A primary chamber 57 is formed between the primary piston 48 and the secondary piston 49, and a primary return spring 59 whose maximum length is regulated by a primary spring retainer 58.
Has been curtailed. A secondary chamber 60 is formed in the axial hole 9 between the master cylinder housing 45 and the secondary piston 49, and a secondary return spring 62 whose maximum length is regulated by a secondary spring retainer 61 is contracted. Have been. In this case, the spring force of the secondary return spring 62 is set to be larger than the spring force of the primary return spring 59.

A radial hole 63 is formed at the front end of the primary piston 48. The radial hole 63 is formed by a gap between the outer peripheral surface of the primary piston 48 and the inner peripheral surface of the axial hole 7, and a cup. A passage hole 64 formed in the cap 47 between the seals 51 and 52, the master cylinder housing 4
5 can communicate with a master cylinder reservoir 66 through a passage hole 65 formed in the same. The passage hole 64 of the cap 47 is composed of a radially extending circumferential groove 64a that opens into the axial hole 7 of the cap 47, and an inclined hole 64b that extends from the circumferential groove 64a in the axial direction. . The passage hole 64 and the passage hole 65 constitute a supply passage for the brake fluid to the primary chamber 57.

In the illustrated inoperative position of the primary piston 48, the radial hole 63 is located slightly behind the cup seal 52. In this case, the primary chamber 57 communicates with the master cylinder reservoir 66, but the primary chamber 57 communicates with the master cylinder reservoir 66. When the radial hole 63 is positioned forward of the cup seal 52 by the advance of the piston 48, the primary chamber 57 and the reservoir 66 for the master cylinder are shut off in the direction from the primary chamber 57 to the reservoir 66 for the master cylinder,
A master cylinder pressure is generated in the primary chamber 57.

A radial hole 67 is formed at the front end of the secondary piston 49.
Are formed in the gap between the outer peripheral surface of the secondary piston 49 and the inner peripheral surface of the axial hole 8, the passage hole 68 formed in the sleeve 46 between the cup seals 55 and 56, and the master cylinder housing 45. It can communicate with the reservoir 66 for the master cylinder through the passage hole 69. And
The passage hole 68 and the passage hole 69 constitute a supply passage for the brake fluid to the secondary chamber 60.

When the secondary piston 49 is in the inoperative position shown in the figure, the radial hole 67 is located slightly behind the cup seal 56. At this time, the secondary chamber 60 communicates with the master cylinder reservoir 66. When the radial hole 67 is located forward of the cup seal 56 by the advance of the piston 49, the secondary chamber 60 and the reservoir 66 for the master cylinder are shut off in the direction from the secondary chamber 60 toward the reservoir 66 for the master cylinder,
A master cylinder pressure is generated in the secondary chamber 60.

The primary chamber 57 is connected to a wheel cylinder of one of the two brake systems through a hole 70 formed in the sleeve 46 and a primary output port 71 formed in the housing 45 for the master cylinder. In addition, the secondary chamber 60 is connected to a wheel cylinder (not shown) of the other of the two brake systems through a secondary output port 72 formed in the master cylinder housing 45. Note that the reservoir 41 for the hydraulic booster can also be used as the reservoir 66 for the master cylinder.

Next, the operation of the brake fluid pressure generating device 1 of the first example configured as described above will be described. First, a predetermined pressure is accumulated in the accumulator 43, and the accumulator pressure is introduced to the axial hole 12 f of the power piston 12. When the brake pedal is not depressed and the brake is not operated, the pump 40 is stopped, the input shaft 22 does not advance, and the power piston 12 and the valve spool 26 of the hydraulic booster 2 are moved as shown in FIGS. In the non-operation state shown in FIG. That is, since the first and second hydraulic pressure supply valves are closed and the discharge valve is open, the power chamber 13 is connected to the hydraulic booster reservoir 4.
1 connected. For this reason, since the pump discharge pressure and the accumulator pressure are not supplied to the power chamber 13, the power piston 12 does not operate and the hydraulic booster 2 does not output.

The step 19b of the reaction force piston 19 is separated from the step 22a of the input shaft 22, and the front end of the reaction force piston 19 is in contact with the power piston 12. In this state, the ring member 24 of the input shaft 22 comes into contact with the reaction force piston 19, and the input shaft 24 is at the retreat limit with respect to the reaction force piston 19. Further, the master cylinder 3 does not operate, the radial hole 63 of the primary piston 48 is located behind the cup seal 52 as shown in FIG. 3, and the primary chamber 57 is connected to the primary chamber 57 via the radial hole 63 and the passage holes 64, 65. Master cylinder reservoir 66
Is in communication with Further, the radial hole 67 of the secondary piston 49 is located behind the cup seal 56, and the secondary chamber 60 communicates with the master cylinder reservoir 66 via the radial hole 67 and the passage holes 68 and 69. Therefore, no master cylinder pressure is generated in the primary chamber 57 and the secondary chamber 60.

When the brake operation is performed by depressing the brake pedal, the depression of the brake pedal is detected, the operation of the pump 40 is started, and the discharge pressure of the pump 40 is introduced into the hydraulic pressure inlet 30. At the same time, the input shaft 22 advances, so that the valve spool 26 advances according to the stroke of the input shaft 22, the space between the annular groove 26e and the radial hole 17b is cut off, and the conical valve 73a is connected to the valve seat 17d. And the first hydraulic pressure supply valve is opened. At this time, the second hydraulic pressure supply valve is still closed. As a result, the power chamber 13 is disconnected from the reservoir 41 for the hydraulic pressure booster, and is connected to the pump 40 and the accumulator 43.
The pump pressure and the accumulator pressure are introduced through the opened first hydraulic pressure supply valve.

Then, the hydraulic piston introduced into the power chamber 13 causes the power piston 12 to move forward, so that the hydraulic booster 2 operates to output. At the start of the operation of the hydraulic booster 2, since the pump discharge pressure is not so high,
A relatively high accumulator pressure mainly introduced from the accumulator 43 causes the power piston 12 to move forward. Therefore, the hydraulic booster 2 starts to operate quickly and outputs, and the delay at the start of operation is reduced.

As the power piston 12 advances, the primary piston 48 advances and its radial hole 63 passes through the cup seal 52, and a master cylinder pressure is generated in the primary chamber 57. Further, due to the master cylinder pressure generated in the primary chamber 57, the secondary piston 49 moves forward, the radial hole 67 passes through the cup seal 56, and the master cylinder pressure is also generated in the secondary chamber 60. Each master cylinder pressure generated in the primary chamber 57 and the secondary chamber 60 is introduced from the primary output port 71 and the secondary output port 72 to each wheel cylinder of each system. At this time, both pistons 48,
Since the effective pressure receiving areas 49 are set to be equal to each other, the master cylinder pressures of the primary chamber 57 and the secondary chamber 60 are the same, and the same hydraulic pressure is supplied to each wheel cylinder. The brake pressures of the two 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, etc., the hydraulic pressure in the power chamber 13 is not so high yet, and the reaction force piston 19 is driven by the reaction force control spring. No retraction against the spring force of 21
9 does not reach the step 19b of the input shaft 22. As described above, since the step 19 a of the reaction force piston 19 does not abut on the step 22 a of the input shaft 22, no reaction force is applied to the input shaft 22 from the reaction force piston 19. Therefore, in the initial stage of operation, the hydraulic booster 2
Performs a so-called jumping action.

When the fluid pressure in the power chamber 13 further rises and the power piston 12 further advances, and the loss stroke of each wheel cylinder is eliminated, each wheel cylinder generates a braking force, and substantially the two brake systems The brakes are activated. In this state, the raised power chamber 13
Is a predetermined pressure, and the reaction pressure piston 19 retreats against the spring force of the reaction force control piston 21 by this liquid pressure. Then, the step portion 19b of the reaction force piston 19 comes into contact with the step portion 22a of the input shaft 22, and the reaction force piston 19 applies a reaction force to the input shaft 22 by the urging force of the hydraulic pressure in the power chamber 13 so that the input force of the input shaft 22 is input. And the jumping action ends.

Further, in this state, since the pump discharge pressure rises and the control piston 42c of the accumulator pressure supply passage shut-off valve 42 is actuated against the spring force of the spring 42b, the control piston 42c is released. After the stroke, the annular groove 42a comes off the passage connecting the hydraulic pressure inlet 30 and the accumulator 43, and this passage is blocked. Moreover, in this state of the hydraulic booster 2, the power piston 1
2 is located forward of the seal member 29, the second hydraulic pressure supply control valve is opened, and the power chamber 13
And the hydraulic pressure inlet 30 are formed in the annular groove 3 of the power piston 12.
4, a gap between the outer peripheral surface of the power piston 12 and the inner peripheral surface of the axial hole 6, and a reduced diameter portion 32 of the power piston 12.
Will be connected via.

As a result, no accumulator pressure is introduced into the power chamber 13 and only the pump discharge pressure is reduced to the power chamber 1.
The hydraulic pressure in the power chamber 13 is increased by only the pump discharge pressure. In that case, the pump discharge pressure is mainly introduced into the power chamber 13 through the opened second hydraulic pressure supply control valve. Also, when the hydraulic pressure booster 2 is operated, the pump discharge pressure is maintained at the accumulator 4.
When the accumulated pressure is higher than 3, the pump discharge pressure is also supplied to the accumulator 43, and the accumulator 43 is maintained at a predetermined accumulator pressure.

The hydraulic pressure in the power chamber 13 due to the discharge pressure of the pump 40 introduced into the power chamber 13 is discharged to the reservoir 41 while being narrowed by the gap between the annular groove 26e and the radial hole 17b, and is adjusted according to the gap. The hydraulic pressure in the power chamber 13 acts as a reaction force on the input shaft 22 so that the input shaft 2
2 is controlled to a pressure corresponding to the input.

When the input of the input shaft 22 further rises, the valve spool 26 advances again with respect to the sleeve 17.
Then, since the gap between the annular groove 26e and the radial hole 17b is further reduced, the flow of the pressure fluid discharged from the power chamber 13 to the reservoir 41 for the hydraulic pressure booster is further reduced, and the power chamber is discharged by the pump discharge pressure. The fluid pressure of 13 further rises and is controlled to a pressure corresponding to the increased input of the input shaft 22. In this manner, the hydraulic pressure in the power chamber 13 increases continuously at a predetermined boosting ratio with respect to the input as the input of the input shaft 22 increases due to only the pump discharge pressure. The input of the input shaft 22 is boosted and output at the boost ratio.

The output of the hydraulic booster 2 is used to output the primary chamber 57 and the secondary chamber 6 of the master cylinder 3.
Since the master cylinder pressure generated at 0 is supplied to the wheel cylinders of each system, each wheel cylinder of each system has a large braking force boosted at a normal boosting ratio with respect to the input of the input shaft 22. Is generated, and the brake is operated with this braking force.

When the brake pedal is released and the brake operation is released, first, the input shaft 22, the reaction force piston 19 and the valve spool 26 are all retracted to the right with respect to the power piston 12 and the sleeve 17. I do. Then, the space between the annular groove 26e and the radial hole 17b communicates with a large passage area, and the discharge valve is opened.
Is rapidly discharged to the hydraulic booster reservoir 41, and the hydraulic pressure in the power chamber 13 is rapidly reduced. At the same time, the pump 40 is stopped.

As a result, the primary piston 48, the secondary piston 49, and the power piston 12 are all quickly retracted by the master cylinder pressure in the secondary chamber 60 and the spring force of the secondary return spring 62. With the retraction of the secondary piston 49, the radial hole 67
Passes through the cup seal 56 and is located again behind the cup seal 56, so that the secondary chamber 60 communicates with the master cylinder reservoir 66 again. For this reason, the pressure fluid of the wheel cylinder of the other system is quickly supplied to the secondary chamber 60.
Is discharged to the master cylinder reservoir 66.
Further, the primary piston 48 and the power piston 12 are further retreated by the master cylinder pressure of the primary chamber 57 and the spring force of the primary return spring 59. With the retraction of the primary piston 48, the radial hole 63 passes through the cup seal 52. As a result, the primary chamber 57 communicates with the master cylinder reservoir 66 again because it is located behind the cup seal 52 again. For this reason, the pressure fluid of one wheel cylinder is also quickly discharged to the master cylinder reservoir 66 through the primary chamber 57. As a result, the brakes of both brake systems are quickly released.

When the hydraulic pressure in the power chamber 13 decreases to a predetermined pressure, the front end of the reduced diameter portion 32 of the power piston 12 is located behind the seal member 29, and the second hydraulic pressure supply control valve closes. Also, the reaction force piston 19 advances relative to the power piston 12 and the input shaft 22 due to the spring force of the reaction force control spring 21 and contacts the power piston 12, and the step 19b of the reaction force piston 19 receives the input. Shaft 22
The ring member 24 of the input shaft 22 contacts the reaction force piston 19.

When the rear end of the power piston 12 comes into contact with the plug 10 and comes to the inoperative position shown in FIGS. 1 and 2,
Reaction force piston 19, input shaft 22, and valve spool 2
6 are in the non-operation position shown in FIGS. 1 and 2, and the primary piston 48 and the secondary piston 49 are also in the non-operation position shown in FIGS. As a result, the hydraulic booster 2 stops outputting, the master cylinder 3 loses its master cylinder pressure, and the brake is completely released. At this time, since the pump 40 is stopped, the pump discharge pressure disappears, and the control piston 42c of the accumulator pressure supply passage shut-off valve 42 strokes to the left inoperative position by the spring force of the spring 42b, and the annular groove 42a Is the hydraulic pressure inlet 30 and the accumulator 4
3 is connected. As a result, the accumulator pressure is reduced to the radial hole 17a of the sleeve 17.
Until it is introduced. Thus, the brake fluid pressure generating device 1 enters the non-operation state shown in FIG.

When the pump 40 is out of order and the pump discharge pressure is not introduced into the power chamber 13 at the time of the brake operation in which the brake pedal is depressed, when the input shaft 22 advances greatly, the valve spool 26 also advances greatly and the valve spool 26 further advances. Body 73
Moves forward, and the front end of the valve body 73 contacts the power piston 12 in the axial direction. For this reason, the input shaft 22 is connected to the valve spool 26, the valve body 73, the power piston 12, and the adjusting member 5.
Since the primary piston 48 is pushed directly via 4, the primary piston 48 advances. At this time, the valve body 73 is separated from the valve seat 17d, and the first hydraulic pressure supply control valve is opened. If the accumulator pressure is stored in the accumulator 43, the accumulator pressure is supplied to the power chamber 13. For this reason, the pedal depression force is boosted and the primary piston 48 is pressed.

As a result, the radial hole 63 advances forward from the cup seal 52 and the primary chamber 57 similarly to the above.
And the secondary piston 49 moves forward by the master cylinder pressure in the primary chamber 57, so that the radial hole 67
The cylinder moves further forward and a master cylinder pressure is generated in the secondary chamber 60. The master cylinder pressure in the primary chamber 57 and the secondary chamber 60 is applied to each wheel cylinder of the two-brake system via the primary output port 71 and the secondary output port 72, respectively, as in the case where the pump 40 is operating normally. Is supplied, and the brakes of the two-brake system are operated. In this way, even when the pump 40 fails, the brake operation of the two-brake system is reliably performed.

As described above, the hydraulic booster 2 of the first example
According to the above, in the initial operation in which the pump discharge pressure is low after the start of operation, the power piston 12 is operated mainly by the accumulator pressure, and when the pump discharge pressure reaches a predetermined pressure, thereafter, only the pump discharge pressure is used. Since the power piston 12 is operated, the hydraulic booster 2
At the beginning of the operation, and the responsiveness of the hydraulic booster 2 at the beginning of the operation is effectively improved. In that case, the pump 40 is operated only when the hydraulic booster 2 is operated, so that the durability of the pump 40 is improved and the energy consumption is reduced.

Further, the second hydraulic pressure supply control valve comprises the reduced diameter portion 32 of the power piston 12 and the seal member 29 provided in the axial hole 6 of the hydraulic booster housing 4. Therefore, it is not necessary to use a special component dedicated to the hydraulic pressure supply control valve. As a result, the number of components can be reduced, and the configuration of the system can be effectively simplified. When the pump discharge pressure reaches a predetermined pressure, the introduction of the accumulator pressure into the power chamber 13 is stopped. Therefore, the accumulated pressure of the accumulator 43 is not consumed more than necessary, and the accumulated pressure of the accumulator 43 is short. There is no significant drop between them.

FIG. 4 is a diagram schematically showing a brake fluid pressure generating device to which a second embodiment of the present invention is applied. In each of the following examples, the same reference numerals are given to the same components as those in the earlier examples, and detailed description thereof will be omitted. In the above-described first example, the hydraulic booster 2 and the master cylinder 3 are provided separately, but as shown in FIG. 4, the brake hydraulic pressure generation of the hydraulic booster 2 of the second example is performed. In the apparatus 1, a hydraulic booster 2 and a master cylinder 3 operated by an output of the hydraulic booster 2 are integrally connected. In that case, in the following description, the integrated housing 4 for the hydraulic booster and the housing 45 for the master cylinder are described as the housing 4.

In the first example, the sleeve 17 and the valve spool 26 are provided separately from the power piston 12 and the input shaft 22, respectively. However, in the hydraulic booster 2 of the second example, FIG. The sleeve 17 and the valve spool 26 are provided integrally with the power piston 12 and the input shaft 22, respectively, as shown in FIG. That is, the sleeve 17 and the valve spool 26 of the first example are omitted in the second example.

A structure for supplying and discharging hydraulic pressure to and from the power chamber 13 in the hydraulic booster 2 of the second example will now be described. An input shaft 22 is slidably fitted in an axial hole of the power piston 12, and a rear end of the input shaft 22 is connected to a brake pedal. The input shaft 22 is formed as a stepped shaft having first to fourth diameter portions 22b, 22c, 22d, and 22e whose diameter increases in order from the front end to the rear end. The input shaft 22 has a second
A radial hole 22f opening on the outer periphery of the radial portion 22c, a radial hole 22g opening on the outer periphery of the third radial portion 22d, and an axial hole 22h communicating the radial holes 22f and 22g are formed. ing.

A reaction force piston 19 is slidably fitted in an axial hole of the power piston 12 and
The input shaft 22 is liquid-tightly and slidably fitted to the third and fourth diameter portions 22d and 22e of the input shaft 22. This reaction force piston 1
Numeral 9 extends through the housing 4 in a liquid-tight and slidable manner to the outside of the housing 4.
Is biased backward. Further, the reaction force piston 19 has a radial hole 22 of the power chamber 13 and the input shaft 22.
g is always formed.

The power piston 12 on which the input shaft 22 slides
An annular groove 12d and an axial hole 12e are provided for connecting between the axial hole of the power piston 12 and the outer peripheral surface of the power piston 12, and the axial hole 12e is provided in the axial direction of the outer peripheral surface of the power piston 12 and the housing 4. The annular axial passage 23, which is formed by a gap between the inner peripheral surface and a gap between an outer peripheral surface of a primary piston of the master cylinder 3 described later and an axial inner peripheral surface of the housing 4, and a discharge port 65 formed in the housing 4. It is always in communication with the reservoir 66 for the master cylinder via this. In the second example, the discharge port 31 of the first example is also used as the passage hole 65 of the master cylinder 3. That is, in the second example, the hydraulic pressure in the power chamber 13 is discharged to the master cylinder reservoir 66. In that case, the reservoir 41 for the hydraulic booster and the reservoir 6 for the master cylinder
6 are connected to each other, or the reservoir 41 for the hydraulic booster is also used as the reservoir 66 for the master cylinder.

The discharge valve is constituted by the step between the second and third diameter portions 22c and 22d of the input shaft 22 and the annular groove passage hole 12d. In the non-operating state shown in the figure, the step between the third diameter portions 22c and 22d is located in the middle of the annular groove 12d and the discharge valve is open.
3 is a radial hole 22g, an axial hole 22h, a radial hole 22
f, a gap between the outer peripheral surface of the second diameter portion 22c of the input shaft 22 and the inner peripheral surface of the axial hole of the power piston 12, the annular groove 12
d, an axial hole 12e, an axial passage 23, and a radial passage 65 connected to a master cylinder reservoir 66. Further, when the input shaft 22 advances relatively to the power piston 12 and the step between the third radial portions 22c and 22d comes off the annular groove 12d, the discharge valve is closed and the power chamber 13 is closed.
Is shut off from the master cylinder reservoir 66.

In the hydraulic booster 2 of the second example,
The power piston 5 ends at the front end position of the reduced diameter portion 32 of the first example. That is, the power piston 5 of the second example is not provided with the reduced diameter portion 32 of the first example. Therefore, in the second example, the second hydraulic pressure supply control valve is constituted by the seal member 29 and the rear end 12g of the power piston 12. That is, when the rear end 12g of the power piston 12 is located behind the seal member 29 as shown, the second hydraulic pressure supply control valve is closed, and the rear end 12g is
When it is located forward of 9, the second hydraulic pressure supply control valve is opened.

On the other hand, although the configuration of the master cylinder 3 of the second example is simpler than that of the first example, the basic configuration and basic operation are substantially the same as those of the first example. The description of the same components as those in the first example will be omitted by retaining the same reference numerals. Other configurations and other effects of the brake fluid pressure generating device 1 of the second example are the same as those of the first example.

FIG. 5 is a view similar to FIG. 4, but schematically showing a brake fluid pressure generating device to which a third embodiment of the present invention is applied. In the hydraulic pressure source circuit in the hydraulic booster of the third example, a check valve 38 and an accumulator pressure supply passage shutoff valve 4 are added to the second example shown in FIG.
2 is omitted. Therefore, in this third example, the accumulator pressure is always used during operation, like the pump discharge pressure. During operation, the accumulator pressure is consumed more than in the first and second examples, but only the accumulator pressure is used. , The consumption of the accumulator pressure can be reduced. Other configurations and other operational effects of the brake hydraulic pressure generating device 1 of the third example are the same as those of the second example.

In the hydraulic pressure source circuit in the hydraulic booster 2 of each of the above-described examples, the accumulator pressure supply passage shutoff valve 4
2 is operated directly by the pump discharge pressure. The accumulator pressure supply passage shutoff valve 42 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. . Also,
In the hydraulic booster 2 of each of the above-described examples, the reaction piston 19 has a jumping characteristic. However, in the hydraulic booster of the present invention, the reaction piston 19 is not always necessary and is omitted. You can also. 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.

[0073]

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. In this case, the pump is operated only when the hydraulic booster is operated, so that the durability of the pump is improved and the energy consumption is reduced.

Further, since the second hydraulic pressure supply control valve comprises the reduced diameter portion of the power piston or the rear end of the power piston and the seal member provided in the power piston hole of the housing, the second hydraulic pressure supply control valve is provided. It is not necessary to use a special component dedicated to the control valve. As a result, the number of components can be reduced, and the configuration of the system can be effectively simplified.

The hydraulic booster of the present invention supplements the pump discharge pressure at the beginning of operation, compared with the case where all the operations are performed by the accumulator pressure as in the conventional hydraulic booster having an accumulator. 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 a first embodiment of a hydraulic pressure source circuit in a hydraulic booster according to the present invention is applied.

FIG. 2 is a partially enlarged sectional view of the hydraulic booster shown in FIG.

FIG. 3 is a partially enlarged sectional view of the master cylinder shown in FIG.

FIG. 4 is a diagram schematically showing a brake hydraulic pressure generator to which a second embodiment of the hydraulic pressure source circuit in the hydraulic booster according to the present invention is applied.

FIG. 5 is a diagram schematically showing a brake hydraulic pressure generator to which a third embodiment of the hydraulic pressure source circuit in the hydraulic booster according to the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Brake hydraulic booster, 2 ... Hydraulic booster, 3 ... Master cylinder, 4 ... Housing, 12 ... Power piston, 12b ... Annular groove, 12g ... Rear end of power piston,
13 power chamber, 17 sleeve, 17d radial hole, 1
9: reaction force piston, 22: input shaft, 26: valve spool, 26e: annular groove, 29: sealing member, 30: hydraulic pressure inlet, 32: reduced diameter portion, 38, 64: check valve, 4
0: pump, 41: reservoir for hydraulic booster, 42: accumulator pressure supply passage shut-off valve, 43: accumulator, 66: reservoir for master cylinder, 73: valve body, 7
3a ... conical valve

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[Procedure amendment]

[Submission date] May 16, 2000 (2000.5.1)
6)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D048 BB29 BB45 BB57 CC10 GG03 GG05 GG11 GG17 GG26 GG31 HH14 HH15 HH16 HH38 HH42 HH66 RR35

Claims (2)

[Claims] 1. A reservoir for storing a liquid, an operating member, an input shaft operated by inputting an input by operating the operating member, and a power that is provided in a housing in a liquid-tight and slidable manner and generates an output. A piston, a power chamber defined by a rear end of the power piston, and into which a hydraulic pressure for operating the power piston is introduced; and an operation controlled by the input shaft, connecting the power chamber to the reservoir when not in operation. A hydraulic pressure booster comprising: a control valve for controlling the hydraulic pressure of the power chamber according to 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 apparatus, a pump that is activated when the operation member is operated to generate a pump discharge pressure and an accumulator that stores an accumulator pressure are connected to the pump discharge when the input shaft is activated. Pressure and the accumulator pressure are connected to the power chamber via a normally closed first hydraulic pressure supply control valve that supplies the power chamber with the pump, and the pump controls the pump discharge pressure and the accumulator pressure with the power. A second hydraulic supply control valve connected to the power chamber via a normally closed second hydraulic supply control valve for supplying the power to the power chamber; A rear end of the piston, and a seal member provided in a power piston sliding hole of the housing to slide the power piston in a liquid-tight manner, wherein the reduced diameter portion or the rear end is smaller than the seal member when not in operation. Closed by being located at the rear, shuts off the power chamber and the pump and the accumulator, and when activated, the power piston moves forward and the reduced diameter portion or the rear end is the seal portion. A fluid pressure source circuit in hydraulic booster, characterized in that is adapted to communicating the pump and the accumulator with the power chamber open by more located in front. 2. When the pump discharge pressure becomes equal to or higher than a predetermined pressure in a passage between the accumulator and the first and second hydraulic pressure supply control valves, the accumulator and the first and second hydraulic pressure control valves are connected to each other. 2. The hydraulic pressure source circuit in the hydraulic booster according to claim 1, further comprising a shutoff valve for shutting off the hydraulic pressure supply control valve.