JPH02141358A - Negative pressure booster - Google Patents

Abstract

PURPOSE:To improve the strength of an antislip part and to perform reliable antislip by a method wherein the press part of a reaction disc is mounted to a retainer to perform antislip of the output shaft of a negative pressure booster device separately from the antislip part. CONSTITUTION:In a brake booster device 1, by separation of a valve body 26 of a control valve 24 away from a valve seat 27 when an input shaft 20 is moved rightwardly through step on of a brake pedal, air having a atmospheric pressure flows in a pressure change chamber 10. By means of a difference in a pressure produced between the pressure change chamber and a constant pressure chamber 9, a power piston 8 is moved, and a master cylinder, not shown, is driven through an output shaft 29. A retainer 33 prevents the output shaft 29 from a slipping off from a recessed part 11 formed in a valve body 4. In this case, the retainer 33 is formed such that inner and outer ring members 33a and 33b, a plurality of arm members (antislip parts) 33c coupled thereto, and an circumferentially-extended extension part (press part) 33d formed at the intermediate part of each arm member 33c are integrally formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a negative pressure booster used in a brake booster, etc., and particularly relates to a negative pressure booster equipped with a reaction disk. .

(Prior Art) Conventionally, in a brake booster using negative pressure, the brake reaction force is transmitted to the brake pedal by a reaction force means in order to allow the driver to sense the magnitude of the braking force during operation. .

As one of such reaction force means, Utility Model Application No. 57-709
2. Description of the Related Art A reaction disk made of an elastic member is known, as disclosed in Japanese Patent No. 64 and the like.

This reaction disc is disposed in a recessed part formed at the front end of the valve body of the brake booster. The rear end of the output shaft is in contact with the front surface of this reaction disk, and the front end of a valve plunger connected to the input shaft is opposed to the rear surface of the reaction disk.

When the negative pressure booster operates and the output shaft operates the brake mask cylinder, the reaction force is transmitted to the reaction disk via the output shaft.

For this reason, the reaction disk deforms elastically according to the magnitude of the reaction force, and uses its elasticity to transmit the reaction force to the valve plunger, which in turn reacts to the brake pedal via the input shaft connected to it. It is designed to convey power. In this way, the driver can sense the magnitude of the braking force.

(Problem to be Solved by the Invention) By the way, in a negative pressure booster equipped with such a reaction disk, in order to transmit reaction force from the output shaft to the valve plunger via the reaction disk, the reaction disk is The recessed part in which the valve is disposed has a structure that has no choice but to communicate with the valve plunger side.

However, if the structure is such that the recessed fitting part communicates with the valve plunger side, when the brake booster is activated, the atmosphere will enter the recessed fitting part from the valve plunger side and act on the rear surface of the reaction disk. . In this way, when the atmosphere acts on the rear surface of the reaction disk, the negative pressure of the constant pressure chamber acts on the front surface of the reaction disk, so a pressure difference is created between the front and rear surfaces of the reaction disk, causing the reaction disk to A forward force is applied. However, at the very beginning of operation, braking force has not yet been generated and the braking reaction force is not transmitted to the reaction disc via the output shaft, so the reaction disc moves slightly forward due to this force. As a result, the rear surface of the reaction disk rises slightly from the bottom of the recessed fit, and the atmosphere enters the constant pressure chamber where negative pressure is maintained at all times through the tiny gap between the rear surface of the reaction disk and the bottom of the recessed fit. I come to do it. As a result, a problem arises in that the output of the negative pressure booster is lost.

To address this problem, the booster shown in the above-mentioned publication uses spring means to force the reaction disk towards the valve plunger. Therefore, by doing this, even if atmospheric pressure is initially applied to the rear surface of the reaction disk during braking, the reaction disk is prevented from moving forward due to the biasing force of the spring means.

By the way, in this booster, a spring means for pushing the reaction disk is used to prevent the output shaft from coming off.

However, if the output shaft is also used to prevent the output shaft from coming off in this way, in order to ensure sufficient strength to prevent the output shaft from coming off, it is necessary to increase the spring constant of the pressing portion that presses the reaction disk. Therefore, if the spring constant of the pressing portion is increased, the suppressing load of the reaction disk will vary greatly. For this reason, the jumping load required of the booster at the initial stage of operation is also large (varies), making it impossible to obtain good jumping characteristics.

In addition, if the spring constant of the pressing part is made small in order to obtain good jumping characteristics, it becomes impossible to ensure sufficient strength to prevent the output shaft from coming off, which causes the problem that the output shaft easily comes off from the recessed part. occurs.

The present invention was made in view of these problems, and its purpose is to provide a negative pressure that can ensure sufficient strength to prevent the output shaft from coming off while providing good jumping characteristics. The purpose is to provide a booster.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a retainer with a retaining portion for the output shaft, and a reaction disk on both sides of the retainer that is attached to the valve plunger side. It is characterized by forming a pressing portion that elastically presses toward.

(Function) In the negative pressure booster according to the present invention having such a configuration, the output shaft retaining portion and the reaction disk pressing portion are formed separately. As a result, the strength of the retaining portion can be made relatively large, while the spring constant of the pressing portion can be made relatively small.

Therefore, the output shaft is reliably prevented from coming off by this retaining portion.

Further, the right side of the reaction disk is pressed against the bottom of the recessed fitting part by the pressing part with a relatively small elastic force. This ensures airtightness between the right side of the reaction disc and the bottom of the recessed part6.
Therefore, there is no power loss due to vacuum leakage at the very beginning of operation. Also, since the spring constant of the reaction disk is relatively small,
There is almost no variation in the jumping load at the initial stage of operation. Therefore, the jumping characteristic of the negative pressure booster becomes stable and good.

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

FIG. 1 is a longitudinal sectional view showing an embodiment in which a negative pressure booster according to the present invention is applied to a brake booster.

As shown in FIG. 1, the brake booster 1 includes a front shell 2 and a rear shell 3, which are connected by, for example, a bayonet connection.

A valve body 4 is disposed so as to pass through the rear shell 3, and the valve body 4 is supported by the rear shell 3 and the seal member 5 in an airtight and slidable manner. A power piston member 6 is connected to the valve body 4 and is disposed in a space within the single shell 2.3. A diaphragm 7 is provided between the shells 2, 3 and the valve body 4 on the back side of the power piston member 6. The power piston member 6 and the diaphragm 7 constitute a power piston 8, and the power piston 8 divides the space inside both the shells 2 and 3 into a constant pressure chamber 9 and a variable pressure chamber 10.

The valve body 4 is formed with a recessed fitting part 11 that opens into the constant pressure chamber 9, and the bottom of this recessed fitting part 11 is formed with a protruding part 4a whose central portion protrudes toward the constant pressure chamber 9 side.

A first hole 12 that opens into the recessed fitting portion 11 is formed approximately at the center of the protruding portion 4a, and a second hole continues from the first hole 12 in order toward the rear (to the right in the figure). 13,
Third hole 14, fourth hole 15. A fifth hole 16 and a sixth hole 17 opening to the atmosphere are each bored.

The valve body 4 is provided with an axial passage 18 that communicates the negative pressure chamber 9 with the fifth hole 16 .

Further, a valve plunger 1 is provided in the second hole 13 of the valve body 4.
The front end of the valve plunger 9 and the rear end of the valve plunger 19 are slidably fitted into the third hole 14, respectively. An input shaft 20 that is connected to a brake pedal (not shown) is connected to the right end of the valve plunger 19. A radial hole 21 is formed in the valve body 4 so as to be perpendicular to the third hole 14. A key member 22 passes through this hole 21 and is inserted into the valve plunger 19 in an axial direction with respect to the valve plunger 19. They are fitted together for relative movement. Also.

The key member 22, together with the valve plunger 19, has the width of the hole 21 (
In other words, it can be moved in the axial direction by the length (in the axial direction). The key member 22 also prevents the valve plunger 19 from coming out of the valve body 4.

Furthermore, a passage 23 opening into the variable pressure chamber 10 is bored in the valve body 4 so as to be perpendicular to the third hole 14 . This passage 23 communicates with the fourth hole 15 via a passage 14a formed in the third hole 14.

A control valve 24 is provided in the sixth hole 17 of the valve body 4 . This control valve 24 includes a valve element 26 which is always urged in the direction of the valve plunger 19 by the elastic force of a spring 25 interposed between the valve body 4 and the input shaft 20, and the valve plunger 19. A first valve seat 27 formed on the right end of the valve body 4, and a second valve seat 2 formed on the valve body 4.
8. This control valve 24 has a valve body 26 with a first
When seated on the valve seat 27 and separated from the second valve seat 28, the constant pressure chamber 9 and variable pressure chamber 10 are communicated with each other, and communication between the variable pressure chamber 10 and the atmosphere is cut off. When the first valve seat 27 is unseated and the second valve seat 28 is seated, the communication between the constant pressure chamber 9 and the variable pressure chamber 10 is cut off, and the variable pressure chamber 10 is switched to communicate with the atmosphere. It has become.

A right-end large-diameter portion of the output shaft 29 is disposed in the recessed portion 11 of the valve body 4, and the recess formed in the right-end large-diameter portion is slidably fitted into the protrusion 4a of the valve body 4. are combined. A reaction disk 30 is housed in the concave portion of the right-end large diameter portion between the protruding portion 4a of the valve body 4 and the output shaft 29. Moreover, in the first hole 12,
A spacing member 31 is interposed between the reaction disk 30 and the left end of the valve plunger 19. By appropriately changing the cross-sectional area of the spacing member 31, the boost ratio can be changed even if the cross-sectional area of the valve plunger 19 is kept constant. This makes it possible to use the valve plunger 19 in common for various negative pressure boosters.

A predetermined gap is set between the spacing member 31, the valve plunger 19, and the reaction disk 30.

The output shaft 29 is prevented from coming out of the valve body 4 by a retainer 33 which is biased to the right by a return spring 32 which returns the valve body 4 to the non-operating position.

As is clear from FIGS. 2 and 3, this retainer 3
3 is an inner ring portion IJ 33 arranged concentrically.
a and an outer ring member 33b, and these ring members 33a, 33b are connected by four arm members 33c, 33c, . . . arranged perpendicularly to each other. These arm members 33c,
33c, . . . are formed relatively wide to ensure a predetermined strength.

In addition, these arm members 33 c, 33 c, ・
Extending portions 33d, 33d extend in the circumferential direction substantially concentrically with the inner and outer ring members 33a, 33b in the intermediate portions thereof.

... is formed. These extension parts 33d, 33
The widths of the springs d, . . . are relatively small, and therefore the spring constants are set small. The inner ring member 33a has a hole 33e of a size that allows the small diameter portion of the output shaft 29 to pass through, but not the large diameter portion. As is clear from FIG. 3, one set of extension parts 33d, 33d, which are point symmetrical to each other, protrudes in one direction, and the other set protrudes in the opposite direction.

That is, the extending portions 33d, 33d, . . . project almost symmetrically on both sides of the retainer 33.

As shown in FIG. 1, the retainer 33 configured in this manner is disposed to penetrate the small diameter portion of the output shaft 29, and is constantly pressed against the valve body 4 by the return spring 32. In this case, the arm members 33d, 33d on the rear crayon disk 30 side press the large diameter portion of the output shaft 29 toward the valve body 4. Therefore, the reaction disk 30 comes into pressure contact with the front end surface of the protrusion 4a of the valve body 4. The pressing force at this time is the arm member 3
Since the spring constants of 3d and 33d are set small, they are relatively small, so that the reaction disk 30 is pressed against the reaction disk 30 with a relatively weak elastic force. In this way, the extending portions 33d, 33d, . . . serve as pressing portions of the reaction disk 30.

Further, the left end of the output shaft 29 is airtightly and slidably supported by a seal member 34 and protrudes outward from the front shell 2, and the left end is interlocked with a piston of a mask cylinder (not shown) attached to the front shell 2. It is made to be.

The valve body 4 and each power piston 8 connected thereto are normally held in the illustrated inactive position by a return spring 32. In this non-operating state, the key member 2
2 restricts the rightward movement of the valve plunger 19 by coming into contact with the inner surface of the rear shell 3, thereby holding the valve plunger 19 at the backward limit position. When the input shaft 20 is not in operation, the key member 22 is in a forward position relative to the valve body 4, and at this time, the valve body 26 is seated on both the first valve seat 27 and the second valve seat 28. and transformer room 1
0 is isolated from both the atmosphere and the constant pressure chamber 9.

Therefore, during braking, as soon as the valve plunger 19 is actuated by the advancement of the input shaft 20, the valve body 26 and the first valve seat 2
7 are separated from each other, so that the variable pressure chamber 10 and the atmosphere are immediately communicated with each other.

The constant pressure chamber 9 communicates with, for example, an intake manifold of an engine (not shown) via a negative pressure introduction pipe 35 attached to the front shell 2.

Therefore, negative pressure is always introduced into the constant pressure chamber 9.

Next, the operation of this embodiment will be explained.

When the brake booster 1 is in the non-operating position shown, the pressure in the variable pressure chamber 10 is slightly higher than the pressure in the constant pressure chamber 9, and is approximately balanced with the elastic force of the return spring 32.

When the brake pedal is depressed during braking, the input shaft 20 moves forward toward the valve body 4. Input shaft 2
0, the valve plunger 19 moves forward with respect to the key member 22 and the valve body 4. Valve plunger 1
9 moves forward, the first valve seat 2 is moved from the valve body 26 of the control valve 24.
7 leaves.

Therefore, air at atmospheric pressure enters the sixth hole 17, the valve body 26, and the first
It flows into the variable pressure chamber 10 through the gap between the valve seat 27, the passage 14a of the fourth hole 15 and the third hole 14, and the passage 23.

Furthermore, the air that has flowed into the variable pressure chamber 10 passes through the gap between the valve body 4 and the valve plunger 19 in the second hole 13 and leaks into the first hole 12, and this leaked air acts on the rear end surface of the reaction disk 30. It becomes like this. For this reason,
The reaction disk 30 is pushed forward and tries to move away from the protrusion 4a of the valve body 4, but since the reaction disk 30 is pushed backward by the elastic force of the extension 33d of the retainer 33, the reaction disk 30 does not separate from the protruding end surface 4a of the valve body 4. Therefore, the air leaking into the first hole 12 does not further leak toward the constant pressure chamber 9. As a result, output loss caused by air leaking toward the constant pressure chamber 9 is prevented.

The air flowing into the variable pressure chamber 10 causes the power piston 8 to
operates and the valve body 4 moves forward, so the brake booster 1 generates an output via the output shaft 29 to operate the piston of the mask cylinder. However, due to various resistances in the brake circuit after the mask cylinder, no braking effect occurs yet. In the early stages of such operation.

Since predetermined gaps are formed between the spacing member 31 and the reaction disk 30 and between the spacing member 31 and the valve plunger 19, the valve plunger 19 and the reaction disk 30 are engaged with each other via the spacing member 31. There's nothing to do.

Once the aforementioned resistances have been overcome, braking can begin. At this point, the gap between the reaction die 30, the spacing member 31 and the valve plunger 19 has been absorbed, so that the reaction disc 30 and the valve plunger 19 are engaged through the spacing member 31.

Therefore, the reaction force due to braking is transmitted to the driver via the output shaft 2 reaction disc 30, the spacing member 31, the valve plunger 19, and the input shaft 20. At this point, the output has already become quite large compared to the input, and a so-called jumping effect takes place. In that case, there is almost no variation in the jumping load, so the jumping characteristics become stable.

When you release the brake pedal to release the brakes,
Input shaft 20. Valve plunger 19 and key member 22
In both cases, the key member 22 is connected to the hole 21 with respect to the valve body 4.
Move backwards, that is, to the right, until it touches the rear end wall of the As the valve plunger 19 retreats, the first valve seat 27 comes into contact with the valve body 26 and the variable pressure chamber 10 is cut off from the atmosphere, and the valve body 26 separates from the second valve seat 28 and the variable pressure chamber 10 and the constant pressure chamber 9 are separated. communicate with. As a result, the air in the variable pressure chamber 10 flows into the constant pressure chamber 9 and further flows into the intake manifold through the negative pressure introduction pipe 35. In that case.

The valve plunger 19 is at the most retracted position with respect to the valve body 4, and the gap between the valve body 26 and the second valve seat 28 is maximized. Therefore, the air within the variable pressure chamber 10 flows quickly. Therefore, the valve body 4 and the power piston 8 are quickly retracted by the elastic force of the spring 31. - When the key member 22 comes into contact with the inner surface of the rear shell 3, the valve plunger 19 and the key member 22 no longer retreat, but the valve body 4 continues to retreat further. When the second valve seat 28 comes into contact with the valve body 26, the air in the variable pressure chamber 10 will no longer flow out toward the constant pressure chamber 9, so the power piston 8 will no longer retreat and will be at the backward limit position. The valve body 4 and the valve plunger 19 are thus in the initial inoperative position shown.

FIG. 4 is a front view of another embodiment of the retainer 33 according to the present invention. It should be noted that constituent elements corresponding to those of the above-mentioned embodiments are designated by the same reference numerals, and a detailed explanation thereof will be omitted.

As shown in FIG. 4, the retainer 33 is provided with a ring member 33b on the outer peripheral edge, and this ring member 33b
has three relatively wide protrusions 33f, 33f,...
・are formed at equal intervals in the circumferential direction. A pair of extending portions 33g, 33g are formed between these protruding portions 33f, and these pair of extending portions 33g, 33g
One side protrudes in one direction and the other side protrudes in the opposite direction. In this retainer 33, the protruding portion 33f serves as a retaining portion for the output shaft 29, and the extending portion 33
g is a pressing portion of the reaction disk 30.

FIG. 5 shows still another embodiment of the retainer 33, in which the retainer 33 has protrusions 33f similar to the protrusions in FIG. A pair of extending portions 33d, 3 extending in the circumferential direction.
3d is formed.

One of these pair of extensions 33d, 33d projects in one direction and the other in the opposite direction. The protruding portion 33f serves as a retaining portion for the output shaft 29, and the extending portion 33d serves as a pressing portion for the reaction disk 30.

FIG. 6 further shows another embodiment of the retainer 33, which includes inner and outer ring members 33a, 33b and four arm members 3 as shown in FIG.
It is equipped with 3 c, 33 c, ... Between these arm members 33c are extending portions 33g, 33g, . . . extending radially inward from the ring member 33b.
is formed. One set of these extending parts 33g facing each other projects in one direction, and the other set projects in the opposite direction. The arm member 33c serves as a retaining portion for the output shaft 29, and the extension portion 3
3g serves as a pressing portion of the reaction disk 30.

In the retainer 33 of the negative pressure booster of the present invention configured as described above, the retaining part of the output shaft 29 and the pressing part of the reaction disk 30 are formed separately, so the retaining part can be compared. In addition to being able to have a large target strength, the pressing portion can also be made to have a relatively small spring constant. This results in
Not only can the output shaft 29 be prevented from coming off reliably, but also output loss at the initial stage of operation can be prevented without impairing the jumping characteristics of the negative pressure booster 1.

Further, since the pressing portions of the reaction disk 30 are formed so as to protrude from both sides of the retainer 33, there is no need to consider the directionality at all when assembling the retainer 33 or when assembling the retainer 330.

Therefore, incorrect assembling of the retainer 33 will not occur, and the ease of assembly will be improved (and the retainer 33 will be able to reliably perform the suppressing function of the reaction disk 30).

Note that the present invention is not limited to the above-described embodiments, and various design changes are possible.

For example, in any of the embodiments described above, the pressing part is connected to the retainer 33.
Although it is assumed that the same number of pressing parts are provided on both sides of the screen, the number of pressing parts can also be made to be different on each screen. If this is done, the directionality will be impaired, but it will be possible to set two different types of jumping loads.

Further, in the embodiment described above, the retainer 33 is engaged with the valve body 4 by the return spring 32, but other retaining means may also be used.

Furthermore, in the above-described embodiment, the negative pressure booster 1 in which the spacing member 31 was provided between the reaction disk 30 and the valve plunger 19 was used as the negative pressure booster.
The present invention can also be applied to a negative pressure booster that does not use such a spacing member 31. Similarly, it is also possible to apply the present invention to a type of negative pressure booster in which the valve body 26 and the second valve seat 28 are separated from each other during non-operation so that the variable pressure chamber 10 and the atmosphere communicate with each other.

Further, in the above embodiment, the valve body 4 and the power piston member 6 are formed separately, but the present invention can also be applied to a negative pressure booster in which these are formed integrally.

Furthermore, although the above-mentioned embodiments describe the case where the negative pressure booster of the present invention is applied to a brake booster, the present invention can also be applied to other boosters such as a clutch booster. Can be applied.

(Effects of the Invention) As is clear from the above description, in the negative pressure booster according to the present invention, the pressing part of the reaction disk is provided separately from the retaining part in the retainer that prevents the output shaft from coming off. Therefore, the strength of the retaining portion can be increased, and the spring constant of the pressing portion can be reduced. Therefore, not only can the output shaft be prevented from coming off reliably, but also there is almost no variation in the jumping load, so it is possible to prevent output loss at the initial stage of operation without impairing the jumping characteristics of the negative pressure booster. It becomes like this.

In addition, if the pressing parts are provided on both sides of the retainer in almost the same way, incorrect assembly of the retainer can be prevented, which improves ease of assembly. If so, it becomes possible to obtain two types of jumping characteristics.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the negative pressure booster according to the present invention applied to a brake booster, FIG. 2 is a front view of a retainer used in this booster, and FIG. A sectional view taken along the line ■--■ in FIG. 2 and FIGS. 4 to 6 are front views of other embodiments of the retainer, respectively. Figure 2 Figure 3 1... Brake booster (negative pressure booster), 2...
Front shell, 3... Rear shell, 4... Valve body, 9... Constant pressure chamber, 10... Variable pressure chamber, 19...
・Valve plunge Asahi 20... Input line 24... Control valve, 29... Output 41dl, 30... Reaction date 33... Retainer, 33c... Arm member (retaining part), 33d ...Extending part (pressing part), 33
f...Protruding part (retaining part), 33g...Extending part (
pressing part)

Claims (1)

[Claims] a valve body that is arranged to be movable forward and backward in the space formed by the front shell and the rear shell and that penetrates the rear shell in an airtight and slidable manner; A power piston partitioned into a constant pressure chamber into which negative pressure is introduced and a variable pressure chamber into which air at atmospheric pressure is introduced during operation, a valve plunger slidably disposed on the valve body, and connected to the valve plunger. an input shaft disposed in the valve body so as to be movable back and forth; and an input shaft provided in the valve body and actuated by the valve plunger to selectively communicate the variable pressure chamber with the atmosphere or the constant pressure chamber a control valve to be controlled, a reaction disk disposed in a recessed fitting portion formed at a front end portion of the valve body facing the constant pressure chamber, a rear end portion of which is fitted into the recessed fitting portion, and a front end portion an output shaft that penetrates the front shell and protrudes to the outside; and a disk-shaped retainer that is formed with a retaining portion that prevents the rear end portion of the output shaft from slipping out of the recessed fitting portion. The negative pressure booster further includes a pressing portion formed on both sides of the retainer to elastically press the reaction disk toward the valve body.