JPH02193756A - Fluid pressure booster - Google Patents

Abstract

PURPOSE:To obtain a good operation feeling at the initial operation of a main driving piston by communicating the system of a first reaction chamber or an accumulating chamber with a liquid tank via a normally-open type jumping valve which closes when the pressure in a boost chamber exceeds a prescribed pressure. CONSTITUTION:When a main driving piston 19 is moved forward by the input from a brake pedal 2 to introduce a fluid pressure into a boost chamber 132, by receiving the fluid pressure, a booster piston 17 is moved forward to contract the volume of a first reaction chamber 221. However, in such a stage that the fluid pressure in a boost chamber 131 is less than a prescribed value, a jumping valve 80 is opened, and the system of the chamber 221 or a stroke accumulator 65 is opened to a fluid tank 52, therefore a reaction force is not produced in the chamber 221. In other words, a reaction force is not given to the main driving piston 19. When the fluid pressure inside the chamber 131 exceeds a prescribed value, the valve 80 is closed and thereafter a pressure is accumulated in an accumulating chamber 68 from the chamber 221 as the piston 17 moves forward, and the pressure is transmitted to the chambers 221, 222 to provide a reaction force to the piston 19.

Description

Detailed Description of the Invention A9 Object of the Invention (1) Industrial Application Field The present invention relates to a fluid pressure booster that uses fluid pressure to boost a booster piston by following the movement of an operating member; In particular, a booster body, a booster piston that is housed in the booster body to define a boost chamber and moves forward when fluid pressure is introduced into the boost chamber, and a booster piston that is slidably housed in the booster piston and that moves forward when fluid pressure is introduced into the boost chamber; In order to cause the booster piston to follow the forward and backward movements of the driving piston connected to the operating member, the boost chamber and the fluid pressure source and the fluid tank are connected in accordance with the forward and backward movements of the driving piston. This invention relates to an improvement in a device equipped with a control valve for controlling communication and cut-off of the air.

(2) Prior Art Conventionally, in such boosters, the front end surface of the driving piston faces the reaction chamber communicating with the boost chamber, in order to allow the operator to sense the magnitude of the output. For example,
(See Publication No. 2-187).

(3) Problem to be Solved by the Invention-i: Since a high-pressure seal member is attached to the outer periphery of the booster piston, even when fluid pressure is introduced into the boost chamber, the large frictional resistance of the seal member is This causes a slight delay in the operation of the booster piston. For this reason, if the reaction force chamber is communicated with the boost chamber as in the past, when fluid pressure is introduced into the boost chamber, the reaction force will be transmitted to the drive piston before the booster piston starts operating. In the early stages of operation of the driving piston, there is a disadvantage that the operation feeling and the output state do not match, giving the operator a somewhat uncomfortable feeling.

Therefore, in order to obtain a good operational feeling in the initial stage of operation of the main piston, it is required that no reaction force is applied to the main piston until the output reaches a predetermined value that is sufficient to effectively operate the load. Ru.

It is an object of the present invention to provide a simple and effective fluid pressure booster that can satisfy such requirements.

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a booster main body with a first tube whose volume decreases in accordance with the advance of the booster piston.
A reaction force chamber is provided in the booster piston, and a second reaction force chamber is provided in the booster piston which communicates with the first reaction force chamber and whose volume decreases as the driving piston moves forward, and the first reaction force chamber is provided in the pressure accumulation chamber of the stroke accumulator. The system of the first reaction force chamber or the pressure accumulation chamber is connected to the fluid tank via a normally open jumping valve that closes when the pressure of the boost chamber increases to a predetermined pressure or higher.

(2) Effect According to the above feature, when the driving piston moves forward in response to an input from the operating member and fluid pressure is introduced into the boost chamber, the booster piston moves forward in response to the fluid pressure, thereby causing the first reaction to move forward. Although the volume of the force chamber is reduced, when the fluid pressure in the boost chamber is below a predetermined value, the jumping valve is open and opens the first reaction force chamber or stroke accumulator system to the fluid tank. No reaction force is generated in the 1 reaction force chamber. That is, no reaction force is applied to the driving piston.

When the fluid pressure in the boost chamber exceeds a predetermined value, the jumping valve closes, and thereafter, as the booster piston moves forward, pressure is accumulated from the first reaction chamber to the pressure accumulator chamber of the stroke accumulator, and the pressure in the pressure accumulator chamber is increased to the first pressure accumulator chamber. 1. The reaction force is transmitted to the second reaction force chamber and applies a reaction force to the driving piston.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the fluid pressure booster l is for the brakes of an automobile, and is composed of a brake mask cylinder M, a booster B connected to the rear thereof, and a control valve ■ that controls the hydraulic pressure of the booster B. The brake pedal (
When the bushing rod 3 connected to the operating member) 2 moves forward in response to the depression of the brake pedal 2,
A boosting operation occurs in the booster B, and braking hydraulic pressure is generated in the brake mask cylinder M in response.

The brake mask cylinder M is configured in a tandem type.

That is, the cylinder body 4 has a cylinder hole 5 whose front end is closed.
The cylinder hole 5 has a front mask piston 7f defining a front hydraulic chamber 6f between the cylinder hole 5 and the front end wall thereof.
A rear hydraulic chamber 6 is provided between the front mask piston 7f and the front mask piston 7f.
A rear mask piston 7r defining an area r is slidably fitted therein. The front hydraulic chamber 6f has a front return spring 8f that biases the front mask piston 7f in the backward direction, and the rear hydraulic chamber 6r has a rear return spring 8r that biases the rear mask piston 7r in the backward direction. Each is accommodated. Therefore, if the rear mask piston 7r is pushed forward, the front mask piston 7f is also advanced while compressing both return springs 8f and 8r, reducing the volumes of the front and rear hydraulic chambers 6f and 6r. Output boat 9f for hydraulic chambers 6f and 6r.

Braking oil pressure can be outputted from 9r, thereby operating the corresponding wheel brakes 10a and 10b.

An annular guide member 11 is attached to the rear end of the cylinder body 4, and this guide member 11 slidably supports a piston rod 12 protruding from the rear end surface of the rear mask piston 7r, and also supports the rear mask piston 7r. This restricts the retraction limit of the piston 7r.

A first boost chamber 13. is defined.

The front end of the booster body 14 of the booster B is fitted and connected to the outer periphery of the rear end of the cylinder body 4.

A sleeve 15 is fitted onto the inner surface of the booster body 14 so as to press the rear end of the guide member 11. A booster piston 1 is provided in the cylinder hole 16 of this sleeve 15.
7 is also the cylinder hole 18 of this booster piston 17.
A driving piston 19 is slidably fitted in each of the
The bushing rod 3 is connected to the driving piston 19 .

The cylinder hole 16 of the sleeve 15 is the front cylinder hole 16.
The booster piston 17 has a front piston part 17a that fits into the front cylinder hole 16a and a rear cylinder hole 16b that fits into the rear cylinder hole 16b. It has a piston portion 17b. In order to restrict the backward limit of the booster piston 17, a stopper ring 20 capable of supporting the rear end of the rear piston portion 17b is connected to the rear end wall 14a of the booster body 14 and the sleeve 1.
It is sandwiched between the rear end of 5. And booster piston 1
7 and the driving piston 19 are respectively formed with an annular step portion 17c and a shoulder portion 19c that come into contact with each other when the driving piston 19 advances a predetermined amount from the rear end limit with respect to the booster piston 17. The rear end of the booster piston 17 passes through the rear end wall of the booster body 14, and a return spring 21 is compressed between the rear end and the booster body 14 to bias the booster piston 17 in the backward direction. .

A second boost chamber 13□ is defined between the rear surface of the rear piston portion 17b and the rear end wall 14a of the booster body 14, and when hydraulic pressure is introduced into the liquid chamber 138, the booster piston 17 can be moved forward.

In addition, the front surface of the rear piston portion 17b and the rear cylinder hole 16b
A first reaction force chamber 22. is defined, and a liquid chamber 22. The volume of the booster piston 17 is reduced as the booster piston 17 moves forward.

Further, between the front surface of the front piston portion 17a and the guide member 11, there is a portion in front of the booster piston 17.

A breathing chamber 23 that allows rear reciprocating movement is defined, and in the liquid chamber 23, the piston rod 12 and the front piston portion 17a face each other with a small gap g in between.

Further, the cylinder hole 18 of the booster piston 17 includes a front cylinder hole 18a and a rear cylinder hole 18b having a larger diameter.
Correspondingly, the driving piston 19 has:
A front piston part 19a that fits into the front cylinder hole 18a and a rear piston part 19b that fits into the rear cylinder hole 18b.
and has. In order to restrict the backward limit of the driving piston 19, a stopper ring 24 capable of supporting the rear end thereof is locked to the booster piston 17.

An input oil chamber (input fluid chamber) 25 is defined between the front surface of the front piston portion 19a and the front end wall of the front cylinder hole 18. A valve hole 27 that communicates the input oil chamber 25 with the breathing chamber 23 is bored in the front end wall of the front cylinder hole 18a, and a poppet valve 28 that opens and closes this valve hole 27 is connected to the main piston 19.
are concatenated as follows.

That is, the enlarged portion 28a formed at the rear end of the stem of the poppet valve 28 is connected to the guide hole 2 that opens at the front end of the driving piston 19.
The guide hole 2 is slidably fitted into the guide hole 2 by a hatch-shaped rear retainer 30 fitted to the main drive piston 19.
Extraction from 9 is prevented. Further, a hat-shaped front retainer 31 is slidably attached to the intermediate portion of the stem of the poppet valve 28, and a return spring 32 is compressed between the retainers 30 and 31. This return spring 32 uses its elastic force to push the front retainer 31 into the front cylinder hole L8.
While holding the main piston 19 in the abutment position with the front end wall of the main piston 19, the main driving piston 19 is urged in the backward direction. Further, a valve spring 33 that biases the poppet valve 28 in the valve closing direction is housed within the front retainer 31. The spring force of this valve spring 33 is set to be much weaker than that of the return spring 32.

Thus, when the driving piston 19 is located at the backward limit, the poppet valve 28 has its enlarged portion 28a connected to the rear retainer 30.
The valve hole 27 is opened by contacting the main piston 1.
When the poppet valve 9 is advanced, the poppet valve 28 closes the valve hole 27 by the force of the valve spring 33.

A second reaction force chamber 222 is defined between the front surface of the rear piston portion 19b and the front end wall of the rear cylinder hole 18b, and the liquid chamber 22
．． is the first through the horizontal hole 34 of the booster piston 17.
Reaction force chamber 22. It communicates with

The cylinder body 4 and the booster body 14 are provided with first to fifth boats P, -P in order from the front. The first boat P communicates with the first boost chamber 13, and the second boat Pg communicates with the breathing chamber 23 via an annular passage 35 around the sleeve 15. 3rd boat P, sleeve 1
It communicates with the input oil chamber 25 through an annular passage 36 on the outer periphery of the booster piston 17, a lateral hole 37 in the sleeve 15, an annular passage 38 on the outer periphery of the front piston part 17a of the booster piston 17, and a lateral hole 39 in the front piston part 17a. 4th boat P, sleeve 15
The first reaction force chamber 22. The fifth port 1''Ps communicates with the second boost chamber 13□ via an annular passage 42 on the outer periphery of the sleeve 15.

The control valve V is installed at an arbitrary location apart from the booster B, and consists of a valve surface 45, a sleeve 46 fitted to the valve surface 45, and a sleeve 46 that is slidably fitted into the sleeve 46. The valve spool 47 is made up of a valve spool 47. A driven piston 49 is integrally connected to one end of the valve spool 47 and is slidably fitted into a cylinder hole 48 formed in the valve surface 45. An output oil chamber (output fluid chamber) 26 is defined between the end wall and the end wall. The valve spool 47 is urged by the return spring 50 in the direction of reducing the volume of the output oil chamber 26, that is, in the backward direction. An elastic cap 51 is attached to the end of the piston 49 to reduce the shock when the driven piston 49 abuts against the end wall of the cylinder hole 48 due to this biasing force.

On the right side wall of the valve surface 45, the 6th to 9th bows) P are arranged in order from the top.
i to P, and the 10th boat PI is installed on the upper end wall.
6 is provided, and furthermore, the left side wall is provided with an 11th
˜13th port PI 3 is provided.

The sixth boat P communicates with the eleventh port pH via an annular passage on the outer periphery of the sleeve 46, and is open to the oil sump 52 via a conduit.

The 7th port PI is connected to the 12th port PI through the annular passage on the outer circumference of the sleeve 46. It is connected to the fifth boat P of the booster main body 14 via a conduit.

The eighth boat Pa is connected to the discharge port of the hydraulic pump 54 via a conduit L3 that includes an accumulator 53 in the middle. This hydraulic pump 54 is driven by an electric motor 55 and pumps the hydraulic oil from the oil reservoir 52 to the eighth connection point (PI).
and pressure-feeding to the accumulator 53.

The ninth boat PI communicates with the thirteenth boat P13 through an annular passage on the outer periphery of the sleeve 46, and is also connected to the fourth boat P4 of the booster main body 14 through a conduit L4.

The tenth boat pH1 communicates with the output oil chamber 26, and also communicates with the third port of the booster main body 14 via a conduit.
Connected to P3.

The eleventh boat P,1 is connected to the second port P2 of the booster main body 14 via a conduit.

A driven piston 4 is disposed between the sleeve 46 and the valve spool 47.
An outlet valve 56, an inlet valve 57, and an on-off valve 58 are configured in this order from the 9 side. Also, the back of the driven piston 49 and the sleeve 4
A breathing chamber 59 is defined between the end face of the valve spool 4 and the end face of the valve spool 4.
It communicates with a spring chamber 61 that accommodates the return spring 50 through an oil passage 60 in the spring 7 .

The exit valve 56 is the sixth valve. 11th port P&*P)
1 and 7. 12th boat P? +Plt, and is opened at the upper limit of movement (backward 11] I) of the valve spool 47, and closed when it descends (forward).

The large mouth valve 57 is the 8th port Ps and the 7th and 12th ports P
t, P+□, and is closed at the upper limit of movement of the valve spool 47, and opened when the valve spool 47 descends.

The on-off valve 58 opens and closes between the oil passage 60 connected to the breathing chamber 59 and the 9th and 13th boats P 9 * P 12, and is opened at the upper limit of movement of the valve spool 47 and closed when it descends. It has become.

Therefore, the opening/closing timing of the three valves 56, 57, and 58 is such that when the valve spool 47 descends from its upper limit, the opening/closing valve 58 closes first, then the outlet valve 56 closes, and finally the large mouth valve 57 closes. Set to open.

A stroke accumulator 65 is connected to P11 via a conduit. The stroke accumulator 65 includes a stepped cylindrical accumulator main body 66, a cap 67 that closes the outer end of the large diameter portion 66a of the accumulator main body 66, and an accumulator main body 66.
The small diameter portion 66 is slidably fitted into the small diameter portion 66b of No.6.
an accumulator piston 69 defining a pressure accumulation chamber 68 between the end wall of b, a fixed retainer 70 supported by a cap 67 within the large diameter portion 66a, and the accumulator piston 69.
A coil spring 72 is compressed between a movable retainer 71 supported by a coil spring 72 and biases the accumulator piston 69 in the direction of reducing the volume of the pressure accumulating chamber 68; An intermediate piston 73 that slides with the fixed retainer 70 when it moves a predetermined distance or more toward the fixed retainer 70 is interposed between the intermediate piston 73 and the end wall of the cap 67 to spring the intermediate piston 73 toward the accumulator piston 69. Comb spring 74
The large diameter portion 66a is provided with a ventilation hole 75 that allows the inside to breathe.

A fourteenth boat P14 connected to the pressure accumulation chamber 68 is provided on the end wall of the small diameter portion 66b, and the thirteenth boat P14 is connected to this via a conduit.

Booster 81 control valve■ and stroke accumulator 6
A jumping valve 80 is installed between the three parts. This jumping valve 80 includes a cylindrical valve surface 81, a sleeve 82 fitted to this valve surface 81, and a sleeve 82 fitted to this valve surface 81.
is slidably fitted into the valve chamber 83 and the pressure receiving chamber 8.
The valve body 85 is divided into four sections. The valve body 85 opens and closes between valve holes 86 and 87 opening into the valve chamber 83, and is biased in the valve opening direction by a valve spring 88.

On the valve surface 81, a 15th boat P15 connected to the valve hole 86,
The 16th boat PI6 connected to the valve hole 87 and the pressure receiving chamber 84
The 17th. 18th boat P17. PI8
is provided. The 15th boat PUS is connected to the conduit 1, the 16th port 1-P is connected to the 11th port 1-P via the 17th port
is connected to the first port P+ of the brake mask cylinder M via a conduit LIO, and is connected to the 18th port P+a
is a conduit, and the 12th boat Pl of the control valve ■ is connected through the conduit.
connected to.

Next, the operation of this embodiment will be explained.

When the brake pedal 2 is inactive, the main piston 19
The booster piston 17 is held at its retracting limit relative to the booster piston 17 by the force of the return spring 32, and the booster piston 17 is held at its retracting limit relative to the booster body 4 by the force of the return spring 21.

On the other hand, in the control valve V, the valve spool 47 is held at the retraction limit (in the figure, the upward limit) by the force of the return spring 50. In this state, the poppet valve 28 in the booster piston 17 is open to communicate the input oil chamber 25 with the breathing chamber 23, and the outlet valve 56 of the control valve V is open and the inlet valve 57 is closed. Since the on-off valve 58 is open, the output oil chamber 2
5, 26, first and second boost chambers 13. ．． 13□, 1st
Both of the second reaction force chambers 228 and 22z communicate with the oil reservoir 52. Therefore, before the brake mask cylinder M,
The rear mask pistons 7f and 7r have front and rear return springs 8f,
8r, the accumulator piston 69 of the stroke accumulator 65 and the valve body 85 of the jumping valve 80 are held in the retracted position by the coil spring 72 and the valve spring 88, respectively.

In order to brake the car in this situation, brake pedal 2
When the driver depresses the brake pedal 2, the driving piston 19 is pushed forward via the bushing rod 3 from the brake pedal 2. As soon as the driving piston 19 moves forward, the poppet valve 28 opens the valve hole 2.
7 is closed to cut off the communication between the input oil chamber 25 and the breathing chamber 23, so that the input oil chamber 25 is
The hydraulic pressure generated in is passed through the conduit to the output oil chamber 2 of the control valve ■.
6, and in response to the hydraulic pressure, the driven piston 49 descends together with the valve spool 47 against the force of the return spring 50.

According to the lowering of the valve spool 47, the on-off valve 58 is closed first, then the outlet valve 56 is closed, and finally the large mouth valve 58 is closed.
7 opens. For this reason, the first boost chamber 13+ is a conduit. , L7, the inlet valve 57, and the conduit line, and the second boost chamber 13□ also communicates with the accumulator 53 via the conduit L2, the large mouth valve 57, and the conduit L3. 1,
Pressure oil is supplied to the second boost chambers 131 and 132, and both chambers 13. ．． 13□ is equally pressurized, and the rear mask piston 7
r is the first boost chamber 13. The booster piston 17 moves forward in response to the hydraulic pressure in the second boost chamber 13□, and the booster operation of the brake mask cylinder M starts, and the booster piston 17 moves forward in response to the hydraulic pressure in the second boost chamber 13□ so as to follow the rear mask piston 7r.

Then, when the amount of advance of the booster piston 17 approaches that of the driving piston 19, the pressure in the input oil chamber 25 decreases, contrary to the previous step, so oil flows backward from the output oil chamber 26 to the input oil chamber 25, and as a result, the driven piston 49 is raised together with the valve spool 47 by the force of the return spring 50, and when the large mouth valve 57 and the outlet valve 56 are both closed, the first. Second boost chamber 13, . Since the supply of pressure oil to 13□ and the discharge of oil from the breathing chamber 23 are stopped, the rear mask piston 7r and the booster piston 17 stop moving.

In this way, the rear mask piston 7r and the booster piston 17 move to follow the driving piston 19.

By the way, at the beginning of the boost operation, when the inlet valve 57 opens, the pressure oil in the accumulator 53 flows into the rear mask piston 7.
Applying thrust by directly acting on r is to quickly move the rear mask piston 7r forward regardless of the frictional resistance of the seal member attached to the booster piston 17,
This is effective in smoothing the initial operation of the brake mask cylinder M.

On the other hand, the second boost chamber 13. The booster piston 17 moves forward due to the hydraulic pressure of the first reaction force chamber 22. As the volume of
Until the pressure in the boost chamber 131 reaches a predetermined value, the valve body 85 of the jumping valve 80 is held in the open position by the valve spring 88, and the valve holes 86 and 87 are communicated with each other, so that the conduit The oil that has passed through the valve hole 86. ．． 87 and the conduit L9, the 11th port pH, the 6th port P, and the conduit are sequentially smoothly discharged to the oil reservoir 52, and are not supplied to the stroke accumulator 65. Therefore, the first reaction force chamber 22. Since no hydraulic pressure is generated to resist the forward movement of the booster piston 17, no hydraulic pressure is generated in the second reaction force chamber 221 communicating with the first reaction force chamber 221, and as a result, the driving piston 19 also moves at the beginning of its forward movement. receives no reaction force. Thus, the output oil pressure of the brake mask cylinder M is the second
As shown in the characteristic line a-b shown in the figure, the curve suddenly rises, and as a result, from the brake mask cylinder M to each wheel brake 10,
The play up to the ends of a and 10b can be quickly removed.

When the effective operation of each wheel brake 10a, 10b is started by removing the play, the first. Second boost chamber 13. ．． 1
The pressure in 3□ rises above a predetermined value, and the first boost chamber 13
．． The hydraulic pressure is conduited. The pressure is transmitted to the pressure receiving chamber 84 of the jumping valve 80 through the pressure, and the valve element 85 is closed against the force of the valve spring 88. That is, the valve holes 86 and 87 are shut off.

Then, the oil sent from the first reaction force chamber 22 to the conduit due to the forward movement of the booster piston 17 is supplied to the pressure accumulation chamber 68 of the stroke accumulator 65, and the accumulator piston 69 moves while compressing the coil spring 72. However, when the amount of movement exceeds a predetermined value, the rubber spring 74 is also compressed, and accordingly, both reaction force chambers 22.
Hydraulic pressure is generated in 222 and the pressure accumulation chamber 68. That is, the oil pressure is applied to the coil spring 7 against the accumulator piston 69.
2 and the repulsive force of the rubber spring 74 increases.

In this way, the booster piston 17 receives the oil pressure of the first reaction force chamber 22, that is, the reaction force from the stroke accumulator 65 and the reaction force from the return spring 21, and the total reaction force increases as the booster piston 17 moves forward. .

On the other hand, the hydraulic pressure of the second reaction force chamber 22□, which communicates with the first reaction force chamber 221, acts on the main driving piston 19 as a reaction force against the depression force on the brake pedal 2, and this reaction force causes the booster piston 17 to move forward. It cannot occur before.

And then, the second boost chamber 13! The thrust of the booster piston 17 due to the hydraulic pressure is balanced with the total reaction force acting on the booster piston 17. Therefore, as the amount of depression of the brake pedal 2 increases, the stroke accumulator 65 and the spring of the return spring 21 increase. A reaction force is applied that increases depending on the characteristics, and the operator can sense the magnitude of the braking force from this.

Hydraulic power source system, for example, hydraulic pump 54, accumulator 53
In the event of a failure such as, the movement of the main piston 19 causes the first
．． Second boost chamber 13. ．． Since oil pressure cannot be generated at 13□, the jumping valve 80 remains open and continues to open the pressure accumulation chamber 68 of the stroke accumulator 65 to the oil reservoir 52.

Therefore, the reaction force of the stroke accumulator 65 against the movement of the booster piston 17 disappears, and the return spring 2
Only the force 1 (which is set relatively weak) remains as a reaction force.

When the brake pedal 2 is depressed in such a case, the driving piston 19 brings its shoulder 19c into contact with the annular stepped portion 17c of the booster piston 17, mechanically moving it forward, and further pushes the booster piston 17 into the rear mask piston. 7r to mechanically move it forward. Therefore, the brake mask cylinder M can be manually operated without being resisted by the stroke accumulator 65.

In such a fluid pressure booster 1, separating the booster B and the control valve 1 and connecting them with a conduit leads to a significant reduction in the size of the booster B, as well as a reduction in the size of the booster B and the control valve. This allows individual Vs to be freely placed, making it easy to install them, for example, in the narrow engine room of an automobile.

Although the embodiments of the fluid pressure booster according to the present invention have been described in detail above, the present invention is not limited to the above embodiments, and in carrying out the invention, the configuration described in the claims may be departed from. (Various design changes are possible.)

For example, the hydraulic pressure introduced into the first boost chamber 131 may be directly used for the braking hydraulic pressure of the wheel brakes.
Alternatively, the boost chamber may be made only of the second boost chamber 13□, and the brake mask cylinder M may be directly actuated by the advancement of the booster piston 17 by the hydraulic pressure introduced into the liquid chamber.

C0 Effects of the Invention As described above, according to the present invention, a first reaction force chamber whose volume decreases as the booster piston moves forward is provided in the booster main body, and a first reaction force chamber is provided in the booster piston and communicates with the first reaction force chamber to provide an active movement. A second reaction force chamber whose volume decreases as the piston moves forward is provided, the first reaction force chamber is communicated with the pressure accumulation chamber of the stroke accumulator, and the system of the first reaction force chamber or pressure accumulation chamber is connected to the boost chamber. It communicates with the fluid tank via a normally open jumping valve that closes when the pressure rises above a predetermined pressure.In the early stages of operation of the main piston, the action of the jumping valve prevents the main piston from reaching a predetermined value. It is possible to prevent unnecessary actuation reaction force from acting on the actuator.

Then, when the output exceeds a predetermined value and the load becomes effective, the stroke accumulator applies a reaction force to the driving piston, and the reaction force corresponds to the effective output situation, so it is possible to operate the load effectively. You can get the feeling.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of a fluid pressure booster, and FIG. 2 is a characteristic diagram thereof. ■... Control valve 1... Fluid pressure booster, 2... Brake pedal as an operating member, 13. ．． 13! ...Boost room, 14
...Booster body, 17...Booster piston, 1
9... Main drive piston, 22. ...first reaction force chamber, 22
g...Second reaction force chamber, 52...Oil reservoir as a fluid tank, 53.54...Accumulator and hydraulic pump as a fluid pressure source, 65...Stroke accumulator, 68...Accumulation chamber , 80... Jumping valve Fig. 2

Claims (1)

[Scope of Claims] A booster body, a booster piston housed in the booster body so as to define a boost chamber, and that moves forward when fluid pressure is introduced into the boost chamber, and a booster piston that is slidable on the booster piston. A driving piston housed therein and connected to the operating member;
In a fluid pressure booster equipped with a control valve that controls communication and isolation between a boost chamber, a fluid pressure source, and a fluid tank in accordance with the backward movement, a volume is increased in the booster body in accordance with the advance of the booster piston. A first reaction force chamber is provided in the booster piston, and a second reaction force chamber is provided in the booster piston, which communicates with the first reaction force chamber and whose volume decreases in accordance with the advance of the driving piston. It communicates with the pressure storage chamber of the accumulator, and this first
A fluid pressure booster characterized in that a system of a reaction force chamber or a pressure accumulation chamber is communicated with a fluid tank via a normally open jumping valve that closes when the pressure of the boost chamber increases to a predetermined pressure or higher.