JPH0260871A - Reaction device of hydraulic booster - Google Patents

Abstract

PURPOSE:To sufficiently display jumping characteristics by providing a reaction force chamber in which pressurized liquid introduced in a power chamber is introduced and providing a movable member working when hydraulic pressure in the reaction force chamber reaches to a predetermined level for applying reaction force to an input shaft. CONSTITUTION:A pedal is stepped on, an input shaft 19 is moved forward, immeadiately, a ball 40 parts from a valve seat member 43 and pressurized liquid in a pressure chamber 45 is introduced in a power chamber 17. After load loss is overcome, braking force is generated. And the pressurized liquid is introduced in a reaction force chamber 30. Accordingly, also the liquid pressure is applied to a movable member 29, at the quite early time after the introduction of the pressurized liquid, since liquid pressure in the reaction force chamber 30 is small, the movable member 29 compresses a spring 27 and it does not move rightward. As the liquid pressure becomes higher, the member 29 compresses the spring 29 and moves rightward, when the liquid pressure reaches to a predetermined level, the member 29 abuts to the step portion 28 of a cylindrical member 22, as a result, the member 29 becomes to apply reaction force according to the volume of the liquid pressure to the input shaft 19 via the cylindrical member 22.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic booster used in a brake booster, etc., which performs servo control of input and output at a predetermined servo ratio, and particularly relates to , relates to a reaction force device for a hydraulic booster that applies a reaction force to an input shaft during operation.

(Prior Art) In general, a hydraulic booster includes a power piston that is slidably fitted into a housing, a power chamber into which hydraulic pressure acting on one end of the power piston is introduced, and a hydraulic booster that is connected to the power chamber. The power supply includes a control valve that switches and controls communication with a source or a reservoir, an input shaft that operates the control valve, and an output shaft that is connected to a power piston. By operating the input shaft and switching the control valve, hydraulic pressure from a hydraulic pressure source is introduced into the power chamber, and the hydraulic pressure operates the power piston to output from the output shaft.

In that case, the hydraulic booster performs so-called servo control, which controls the magnitude of the output of the output shaft in response to the magnitude of the input of the input shaft.

By the way, in such a hydraulic booster, in order for the driver to be able to sense the magnitude of the output, the reaction force at the time of output is transmitted to the driver by being applied to the input shaft. A reaction force device is provided.

A general example of such a reaction force device is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-60359. The reaction force device disclosed in this publication is constructed by arranging an input shaft such that its tip faces the power chamber. According to this reaction force device, the hydraulic pressure introduced into the power chamber when the hydraulic pressure booster is activated not only acts on the power piston;
It also acts on the input shaft. Therefore, a reaction force is applied to the input shaft, and the driver can sense the reaction force and know the magnitude of the output.

(Problem to be Solved by the Invention) By the way, due to the load loss due to the resistance force of each ref-spring of the brake booster and the operated devices such as the mask cylinder operated by the brake booster, there is a problem in the power chamber. Even if pressurized fluid is introduced, no braking force is generated until the fluid pressure reaches a predetermined level.

Therefore, such reaction force devices are given a jumping characteristic that prevents the reaction force from being transmitted to the driver at the very beginning of operation until braking force is actually generated, in order to provide a good operating feeling. It is required to obtain the following.

However, in the reaction force device described above, the input shaft faces directly to the power chamber, so when hydraulic pressure is introduced into the power chamber during operation, that hydraulic pressure immediately acts on the input shaft. , the reaction force is transmitted to the driver before any braking force is actually generated. For this reason, the driver may be under the illusion that braking force is already being generated, and a good operational feeling may not be obtained. As described above, the conventional reaction force device as described above cannot sufficiently meet the jumping characteristics required of the reaction force device.

The present invention was made in view of the above circumstances, and its purpose is to prevent reaction force from being applied to the input shaft until an actuating force such as a braking force is actually generated at the very beginning of operation. It is an object of the present invention to provide a reaction force device in a hydraulic pressure booster that fully exhibits jumping characteristics.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a reaction chamber into which a pressure fluid is introduced into the power chamber, and maintains the fluid pressure in the reaction chamber at a predetermined level. It is characterized by the provision of a movable member that is activated to apply a reaction force to the input shaft when the input shaft reaches a certain size.

(Function) According to the reaction force device in the hydraulic pressure booster according to the present invention having such a configuration, when the input shaft is operated and the control valve is switched, and pressure fluid is introduced into the power chamber, the fluid is Pressure is applied to the power piston.

While the hydraulic pressure is low, there is a load loss, so no operating force such as braking force is generated.

At the same time, the pressure fluid introduced into the power chamber is also introduced into the reaction force chamber, and the fluid pressure is applied to the movable member. However, while the hydraulic pressure is lower than a predetermined level, the movable member does not act on the input shaft, and when the hydraulic pressure reaches a predetermined level, the movable member operates and responds according to the level of the hydraulic pressure. Reaction force will be applied to the human power axis. Therefore, the driver senses this reaction force through the human power shaft.

In this way, the reaction force device exhibits jumping characteristics, and a good operational feeling can be obtained.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of a reaction force device in a hydraulic pressure booster according to the present invention applied as a brake booster.

As shown in FIG. 1, the brake booster 1 includes a housing 2 formed in a substantially cylindrical shape. The housing 2 has a first hole 3 opened at the right end of the housing 2 and a second hole 4 opened at the left end of the housing 2 and communicated with the first hole 3 coaxially.

A power piston 5 is disposed in the second hole 4 . This power piston 5 has third and fourth holes 6.7 opened at the right and left ends, respectively, and a fifth hole 8 communicating with these holes 6.7, which are coaxially bored. There is.

A cylindrical member 9 is fluid-tightly fitted into the third hole 6 of the power piston 5, and this member 9 is prevented from sliding relative to the power piston 5 in the axial direction by a ring member 10. . In this member 9, the sixth hole 11 is the third to fifth hole 6.
An axial groove 12 is formed on the outer periphery of the member 9 so as to communicate with the left and right ends of the member 9 .

A plug 13 for liquid-tightly closing the first hole 3 is fixed to the right end of the housing 2 by a nut 14. Also,
An intermediate portion 15 of the plug 13 is fitted into the second hole 4 in a fluid-tight manner, and a left end portion 16 of the plug 13 projects into the third hole 6 of the power piston 5. A power chamber 17 is formed between the plug 13 and the power piston 5.

In the plug 13, the seventh hole 18 is connected to the third to sixth holes 6 to 8.11.
It is drilled coaxially with the An input shaft 19 is slidably fitted into the seventh hole 18 in a fluid-tight manner. A flange portion 20 is formed at the left end of the input shaft 19.
When the input shaft 9 moves backward, that is, moves to the right, the right side of the flange portion 20 comes into contact with the left end of the plug 13, so that the input shaft 19 cannot move further to the right. In other words, this position is the input shaft 19
is at the retraction limit position.

Further, the flange portion 20 is disposed between the right end of the member 9 and a ring-shaped retaining member 21 attached to the power piston 5, so that the flange portion 20 is disposed between the right end of the member 9 and a ring-shaped retaining member 21 attached to the power piston 5. At this time, the input shaft 19 is prevented from being removed from the power piston 5 by the flange portion 20 coming into contact with the removal preventing member 21 . Therefore, the flange portion 20 can move relative to the power piston 5 between the right end of the member 9 and the retaining member 21. Furthermore, a cylindrical member 22 is provided at the left end of the input shaft 19. On the other hand, the right end of the input shaft 19 is connected to a brake pedal (not shown) via a connecting member 23.

The cylindrical member 22 is slidably inserted into the sixth hole 11 of the member 9. Flange portion 2 at the right end of this cylindrical member 22
4 and a ring-shaped member 25 attached to member 9, a compression coil spring 26 is interposed, and this spring 2
The cylindrical member 22 and the input shaft 19 are constantly urged to the right by the urging force of 6. Spring 2 of ring-shaped member 25
A coil spring 27 is also disposed on the opposite side from 6. The spring 27 is applied to the left side with a predetermined elastic force until the movable member 29, which is fluid-tightly and slidably fitted into the sixth hole 11, comes into contact with the step formed in the sixth hole 11. It's biased towards you. When the input shaft 19 is at the backward limit position shown in the figure,
The right end of the movable member 29 is located a predetermined amount ahead of, or to the left of, the stepped portion 28 formed on the cylindrical member 22 .

A reaction force chamber 30 is formed in the sixth hole ll between the member 9 and the movable member 29. The movable member 29 is urged to the right by the hydraulic pressure in the first reaction force chamber 30, but the liquid When the pressure is smaller than a predetermined level, the movable member 29 does not move. When the hydraulic pressure reaches a predetermined level and overcomes the biasing force of the spring 27, the movable member 29 compresses the spring 27 and moves to the right. It moves and comes into contact with the stepped portion 28 .

An axial passage 32 communicating with the hole 31 of the cylindrical member 22 is bored at approximately the center of the human power shaft 19, and a diametric passage 33 communicating with the right end of this passage 32 is bored. . This passage 33 communicates with an annular groove 34 formed in the plug 13 , which communicates with an annular chamber 34 between the housing 2 and the plug 13 via a diametric passage 35 bored in the plug 13 . is connected to. Furthermore, the annular chamber 36 communicates with a reservoir 39 via an outlet 37 and an outlet conduit 38 formed in the housing 2 .

A valve body 41 having a ball 40 at its right end is slidably supported by a support member 42 and is disposed in the fifth hole 8 of the power piston 5 . Further, a cylindrical valve seat member 43 is fixed at the right end of the fifth hole 8, and the ball 40 of the valve body 41 is seated on this valve seat member 43 by the biasing force of the compression coil spring 44. A pressure chamber 45 is defined by the zero bulb 40 , the seal portion of the valve seat member 43 , and the support member 42 . Further, the left end of the cylindrical member 22 faces the ball 40 within the hole 46 of the valve seat member 43. When the input shaft 19 moves forward, that is, to the left, with respect to the power piston 5 against the biasing force of the spring 26, the left end of the cylindrical member 22 contacts the ball 40, thereby closing the hole 31. , communication between the power chamber 17 and the reservoir 39 is cut off. Further, when the input shaft 19 moves to the left, the valve body 41 is also moved to the left, and the ball 40 is disengaged from the valve seat member 43, so that the pressure chamber 45
and the power chamber 17 are communicated with each other. That is, a valve body 41 including a cylindrical member 22 and a ball 40. A control valve 47 is constituted by the valve seat member 43 and the valve seat member 43 .

An annular spacer 48 is provided in the fourth hole 7 of the power piston 5.
The right end portion of the output shaft 49 is attached to the power piston 5 via a ring-shaped retaining member 50 attached to the power piston 5. This output shaft 49 is configured to operate a piston of a brake mask cylinder (not shown) that is fixed to the left end of the housing 2. A compression coil spring 52 disposed between a plug 51 screwed into the housing 2 and the power piston 5 constantly urges the output shaft 49 and the power piston 5 to the right. The power piston 5 moves to the right, that is, in the backward direction, and the cylindrical member 2
When the left end of the piston 2 comes into contact with the ball 40, the force of the spring 52 in the backward direction and the force in the forward direction due to the hydraulic pressure in the power chamber 17 are almost balanced, so the power piston 5 does not move back any further. The state shown in the figure is reached.

When the power piston 5 and the input shaft 19 are both in the illustrated backward limit position, the flange portion 20 is attached to the member 9.
It is located between the right end surface of the locking member 21 and the retaining member 21, spaced apart from them by one eye. That is, when the input shaft 19 is not in operation, the input shaft 19 is held in a predetermined forward position with respect to the power piston 5 away from the retaining member 21 by the flange portion 20 of the input shaft 19 coming into contact with the left end of the plug 13. It has become so.

A spacer 48 is provided between the power piston 5 and the output shaft 49.
A chamber 53 is formed by. This chamber 53 communicates with the power chamber 17 through a passage 54 formed in the power piston 5. Further, the left end of the valve body 41 faces the inside of the chamber 53.

The pressure chamber 45 is a passage 55i provided in the power piston 5.
3 and an annular groove 56 . Further, the groove 56 communicates with a supply port 59 via a hole 57 formed in the housing 2 and a filter 58. This supply port 59 communicates with an accumulator 61 and a discharge side of a pump 62 via a supply conduit 60, and a suction side of the pump 62 communicates with a reservoir 39.
is connected to. Pump 62 and accumulator 61 constitute the hydraulic pressure source of the present invention. Between the accumulator 61 and the pump 62, there is a connection between the pump 62 and the accumulator 61.
A check valve 63 is interposed to allow liquid to flow in the direction toward, but to prevent liquid from flowing in the opposite direction.

Next, the operation of this embodiment will be explained.

When the pump 62 is driven, the hydraulic fluid from the reservoir 39 is introduced into the accumulator 61 via the check valve 63, and the supply conduit 60, five supply ports, the filter 58, and the hole 5 are introduced into the accumulator 61.
7, the groove 56, and the passage 55 into the pressure chamber 45. A constant level of hydraulic pressure is maintained in the pressure chamber 45 and the accumulator 61 at all times.

When the brake pedal (not shown) is depressed in order to brake from the state shown in FIG. 1 in which the brake is not activated, the input shaft 19 moves forward and the ball 40 immediately leaves the valve seat member 43. Pressure liquid in the pressure chamber 45 is introduced into the power chamber 17. After the load loss is overcome, a braking force is generated, and this pressure fluid is also introduced into the reaction force chamber 30. Therefore, hydraulic pressure comes to act on the movable member 29, but at the very beginning after the introduction of the pressure liquid, the hydraulic pressure in the reaction force chamber 30 is small, so the movable member 29 compresses the spring 27 and moves to the right. Therefore, the movable member 29 does not apply a reaction force to the input shaft 19. Also, since the hydraulic pressure also acts on the pressure receiving part at the left end of the cylindrical member 22, the input shaft A reaction force based on the hydraulic pressure acting on this pressure receiving part is applied to 19. However, since the effective pressure receiving area of the pressure receiving portion is extremely small, this reaction force is extremely small and does not deteriorate the brake feeling.

As the hydraulic pressure increases, the movable member 29
Compress 7 and move it to the right. Then, when the hydraulic pressure reaches a predetermined level, the movable member 29 moves to the stepped portion 28 of the cylindrical member 22.
comes into contact with. As a result, the movable member 29 applies a reaction force corresponding to the magnitude of the hydraulic pressure to the input shaft 1 through the cylindrical member 22.
It will be added to 9. Therefore, this reaction force is sensed by the driver as a brake reaction force.

As the power piston 5 moves, the valve seat member 43 also moves to the left, and when the valve seat member 43 comes into contact with the ball 40, communication between the pressure chamber 45 and the power chamber 17 is cut off. Therefore, no more pressure fluid is introduced into the power chamber 17, and the movement of the power piston 5 is stopped. As a result, pressurized fluid is introduced into the power chamber 17 in an amount corresponding to the amount of depression of the brake pedal, that is, the amount of input from the input shaft 19 . Therefore, the output of the output shaft 49 has a magnitude corresponding to the input of the input shaft 19.

Further, the pressure liquid in the power chamber 17 is also introduced into the chamber 53 through the passage 54. Since the hydraulic pressure in this chamber 53 comes to act on the left end of the valve body 41, the force due to the hydraulic pressure in the power chamber 17 applied to the valve body 41 is reduced and the valve body 41 does not move to the left. As a result, the elastic force of the spring 44 does not need to be increased so much.

When the brake pedal is released in order to release the brake operation, the input shaft 19 moves back significantly until the flange portion 20 contacts the retaining member 21 with respect to the power piston 5. Therefore, the left end of the cylindrical member 22 is far away from the ball 40, and the power chamber 17 is communicated with the reservoir 39, and its pressure is reduced. Therefore, the power piston 5 retreats due to the elastic force of the spring 52, and along with this, the power chamber 17
The pressure liquid inside is discharged to the reservoir 39. In that case, since the cylindrical member 22 is largely separated from the ball 40 and a large flow path area is formed, the pressurized liquid in the power chamber 17 can be quickly discharged to the reservoir 39. Therefore, the power piston 5 quickly retreats.

When the flange portion 20 comes into contact with the left end of the plug 13, the input shaft 19 no longer moves back, and only the power piston 5 continues to move back. Therefore, the flange portion 20 also comes to be separated from the retaining member 21. When the ball 40 abuts against the cylindrical member 22 and communication between the power chamber 17 and the reservoir 39 is cut off, the power piston 5 stops retracting and reaches the retracting limit position.

In this state, the input shaft 19 is at a predetermined position advanced relative to the power piston 5, and the cylindrical member 22 is in the position of the ball 4.
0, and the ball 40 is also in contact with the valve seat member 43. Therefore, the power chamber 17 is isolated from both the pressure chamber 45 and the reservoir 39, and a hydraulic pressure approximately equal to the elastic force of the spring 52 is maintained within the power chamber 17.

Therefore, this brake booster 1 exhibits input/output characteristics as shown in FIG. As is clear from Figure 2, from point a where braking force begins to be generated to point b
Up to this point, the braking force begins to increase even though the input hardly increases. That is, the brake booster l has a jumping characteristic. Full load C from point b
Up to this point, the boosting effect is performed by normal servo control.

In the above embodiment, the movable member 29 is brought into contact with the stepped portion 28 of the cylindrical member 22, but the present invention is not limited to this, and the movable member 29 is brought into contact with the input shaft 19. It is also possible to make direct contact.

Further, in the above embodiment, the present invention is applied to a brake booster in which the power chamber 17 is cut off from both the pressure chamber 45 and the reservoir 39 when the prekinesis is activated, but when the brake booster is not activated, the power The present invention can also be applied to a brake booster in which the chamber 17 communicates with the reservoir 39.

Furthermore, the present invention can be used in other hydraulic pressure boosters other than brake boosters, such as clutch boosters.

(Effects of the Invention) As is clear from the above explanation, the reaction force device in the hydraulic pressure booster according to the present invention is provided with a reaction chamber into which the pressure fluid introduced into the power chamber is introduced, and the reaction force There is a movable member that activates when the indoor hydraulic pressure reaches a predetermined level and applies a reaction force to the input shaft, so no reaction force is applied to the input shaft until the hydraulic pressure reaches a predetermined level. Instead, the reaction force device can exhibit jumping characteristics. Therefore, it is possible to obtain an extremely good operational feeling.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment in which a reaction force device in a hydraulic pressure booster according to the present invention is applied to a brake booster;
FIG. 2 is an input/output characteristic diagram of this embodiment.

Claims (1)

[Scope of Claims] A power piston slidably fitted into a hole in a housing, a power chamber into which hydraulic pressure acting on the power piston is introduced, a hydraulic pressure source generating the hydraulic pressure, an input shaft that is movable forward and backward with respect to the power piston; an output shaft that is connected to the power piston; and when the input shaft moves forward toward the power piston, the hydraulic pressure source and the power chamber are communicated with each other. and a control valve that shuts off the power chamber and the reservoir, communicates the power chamber and the reservoir when the input shaft moves backward from the power piston, and shuts off the hydraulic pressure source and the power chamber. In the hydraulic pressure booster, a reaction force chamber is provided into which the pressure fluid introduced into the power chamber is introduced, and when the liquid pressure in the reaction force chamber reaches a predetermined level, it is activated to increase the input voltage. A reaction force device in a hydraulic booster, characterized in that a movable member that applies a reaction force to a shaft is provided.