JPS6253387B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a negative pressure booster for operating a brake master cylinder or the like of an automobile, particularly in a booster shell, in which the front side is connected to the output rod and is constantly pushed in the backward direction by a return spring. A first working chamber is provided on the front and rear sides of the booster piston, and a first working chamber is connected to a negative pressure source at all times. Two working chambers are respectively formed between the booster piston and an input rod connected to the booster piston so as to move forward and backward, and when the input rod moves, the booster piston is caused to follow the movement of the input rod between the first and second working chambers. The present invention relates to a negative pressure booster including a control valve that generates such a pressure difference.

Conventionally, in such a booster, when the input rod is at the retraction limit, in order to maintain the booster piston at a predetermined retraction limit, the control valve connects the second working chamber to the first working chamber. It is arranged to enter a backward switching state in which the pressure is maintained at the same negative pressure as that of the first working chamber. Therefore, when the input rod is moved forward beyond the retraction limit, the input rod remains open until the control valve is switched from the reverse switching state to the forward switching state in which the second working chamber is isolated from the first working chamber and communicated with the atmosphere. The forward stroke of the booster piston is necessarily a dead stroke, and therefore there is some time delay before the booster piston actually begins to operate due to the pressure difference created between the first and second working chambers. Also, even if the booster piston starts moving forward in this way, the output rod
Generally, a small amount of play is set in advance between the actuated part of the actuated device of a negative pressure booster, for example, the actuating piston of a brake master cylinder, to account for manufacturing errors, etc., so that the output rod does not touch the actuating piston. Until the contact occurs, the working piston is kept in an inactive state, and the forward movement of the input rod during this period becomes an invalid stroke with respect to the working piston. For the above reasons, the conventional type has a problem in that when the input rod moves forward, an actuated device such as a master cylinder connected to the output rod is delayed in operation.

The present invention has been proposed in view of the above, and it is possible to appropriately move and adjust the retraction limit of the input rod when the booster is not in operation, thereby solving the above-mentioned problems of the conventional device. It is an object of the present invention to provide a negative pressure type booster having a simple structure that allows movement adjustment operations to be carried out efficiently and easily.
The feature is that a rear extension tube into which the input rod is inserted is connected to the rear wall of the booster shell, an inward flange is formed at the rear end of the extension tube, and the center opening of this inward flange is a stopper member formed at an air inlet port communicating with the second working chamber via the control valve, and further engaged with the inner surface of the inward flange on the input rod to restrict the retraction limit of the input rod; The boss protruding toward the air inlet of the air inlet is screwed into the input rod so that the position thereof can be adjusted, and a lock nut that is adjacent to the rear side of the stopper member and fixes the adjusted position of the stopper member with respect to the input rod is installed outside the air inlet. This is due to the fact that it is threaded onto the rod.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a brake master cylinder M operated by a negative pressure booster S of the present invention has a conventional configuration, that is, an oil tank is provided on the upper side. 40
It consists of a cylinder body 35 equipped with
The piston 34 is connected to the inside through a pair of front and rear relief holes 38 and a suction hole 39, and the piston 34 is connected to the rear end of the cylinder body 35, and the piston 34 is connected to the inside through a pair of front and rear relief holes 38 and a suction hole 39. A stop ring 37 for stopping at the rearward limit position is fixed. When the piston 34 is advanced from the above position, the piston cup 36 passes through the relief hole 38 and generates hydraulic pressure in the hydraulic chamber at the front of the piston cup 36, and the hydraulic pressure operates the wheel brakes (not shown). Can be done.

The inside of the booster shell 1 of the negative pressure booster S is divided into a first working chamber A at the front and a second working chamber at the rear by a booster piston 6 and a diaphragm 2 connected to its back surface.
It is divided into working chamber B. A rear extension tube 1a into which an input rod 11 is inserted is integrally connected to the center of the rear wall of the booster shell 1, and the rear end of the extension tube 1a has a center opening as an air inlet into the booster shell 1. An inward flange 1b formed at 5 is integrally formed. The first working chamber A is always in communication with the intake manifold (not shown) of the internal combustion engine, which is a negative pressure source, through the negative pressure introduction pipe 3, and the second working chamber B is connected to the control valve 4.
Therefore, communication is alternately switched to the first working chamber A or the atmosphere inlet 5. The booster piston 6 has a return spring 7 contracted in the first working chamber A.
The booster shell 1 is always propelled in the backward direction, and the limit of the backward movement is regulated by the annular stop rib 2a formed protrudingly formed on the back surface of the diaphragm 2 abutting against the rear inner wall of the booster shell 1.

The booster piston 6 has a valve cylinder 8 extending rearward at its center, and is slidably supported by a flat bearing 9 provided on the extension cylinder 1a. An input rod 11 is inserted into the valve cylinder 8, and a control piston 10 connected to the tip thereof is slid onto the center of the booster piston 6. The input rod 11 is always urged in the backward direction by the return spring 12, and its retraction limit is reached when the annular movable stopper plate 26 attached to the input rod 11 as follows is inside the inward flange 1b at the rear end of the extension tube 1a. It is regulated by contacting the side.

The input rod 11 has threaded portions 11a at the middle and rear ends.
11b, and the stopper plate 26 is screwed to the front threaded portion 11a via a nut 27 that fits into a hollow boss 29 of a hexagonal cross section of the plate 26 so that the position can be adjusted, These stopper plate 26 and nut 27 constitute a stopper member of the present invention, and boss 29 and nut 27 constitute a boss portion of the stopper member. Similarly, a lock nut 28 is screwed into the front threaded portion 11a adjacent to the rear side of the stopper plate 26 for fixing the adjustment position of the stopper plate 26 with respect to the input rod 11. The stopper plate 2
The boss 29 and nut 27 of No. 6 are made to protrude into the atmosphere inlet 5. If the lock nut 28 is loosened and the stopper plate 26 is rotated, the screwing position of the front nut 27, which rotates together with the plate 26, to the threaded portion 11a will change, so in this way the stopper plate to the input rod 11 will be rotated. The mounting position of 26 can be adjusted as appropriate in the front-back direction. This stopper plate 26 is provided with a ventilation hole 30 that communicates with the atmosphere inlet 5.

Also, a pair of front and rear nuts 31 and 32 are similarly screwed into the rear threaded portion 11b, and a pedal connector 33 is clamped therebetween so as to be adjustable back and forth, and a brake pedal (not shown) is connected to the pedal connector 33. Ru.

The control piston 10 also includes a stopper ring 50.
is fixed, and this stopper ring 50 comes into contact with the front surface of the booster piston 6 during its retraction process, thereby restricting the retraction limit of the control piston 10 and therefore the input rod 11 relative to the booster piston 6.

The control valve 4 is configured in the valve cylinder 8 as follows.
That is, a first valve seat ₁₃₁ surrounding the control piston 10 is formed on the front wall of the valve cylinder 8, and a second valve seat ₁₃₂ is formed at the rear end of the control piston ₁₀ . A flexible first valve body 14 ₁ attached to the piston 10 has movable ends facing each other, and a similarly flexible second valve body whose rear end is fixed to the inner wall of the valve cylinder 8 is attached to the second valve seat 13 ₂ . 14 The movable front ends of _{the two} are opposed to each other. The movable ends of the first and second valve bodies 14 ₁ , 14 ₂ are connected to each other by an annular body 16 having a through hole 15 in the side wall, and the movable end of the second valve body 14 ₂ is connected to the movable end of the second valve body 14 1 , 14 2 . It is urged toward the valve seat ₁₃₂ by the valve spring 17. The inside of the first valve seat 13 ₁ communicates with the first working chamber A through a through hole 18 provided in the booster piston 6, and the first and second valve seats 13 ₁ , 1
The outside of the valve seat ₁₃₂ communicates with the second working chamber B through the side hole 19 of the valve sleeve 8, and the inside of the second valve seat ₁₃₂ communicates with the atmosphere through a flexible air filter 20, 20'. Connects to 5.

A small diameter shaft 1 protruding from the front end of the control piston 10
The rear end of the output rod 21 is slidably fitted into the output rod 0a, and the front end of the output rod 21 passes through a through hole 22 provided in the front wall of the booster shell 1 and is inserted into the booster shell 1.
It faces into the housing 23 which is recessed in the front. The rear end of the output rod 21 contacts a reaction plate 24 supported on the small diameter shaft 10a, and a plurality of reaction levers 25 radially extending between the reaction plate 24 and the booster piston 6 and the control piston 10 are connected to each other as shown in the figure. Interpose it like this.

The cylinder body 35 of the brake master cylinder M is inserted into the housing 23 through a sealing member that is hermetically and slidably fitted into the output rod 21.
Fit the rear end and attach the output rod 21 to the piston 34.
to face.

Next, to explain the operation of this embodiment, in the assembly process, the brake master cylinder M and the booster S
When combined, generally as shown in Figure 3,
The booster piston 6 is located at the retraction limit where the stopper rib 2a abuts the inner surface of the booster shell 1,
On the other hand, the input rod 11 is located at the retraction limit with respect to the piston 6, where the stopper ring 50 comes into contact with the front surface of the booster piston 6, and therefore the first valve seat ₁₃₁ and the first
A gap g ₁ is created between the valve body 14 ₁ and the piston 34
A gap _g2 is created between the output rod 21 and the output rod 21.

Therefore, in this embodiment, first, the negative pressure introducing pipe 3 is connected to a negative pressure source to introduce negative pressure into the first working chamber A, and then the mounting position of the stopper plate 26 with respect to the input rod 11 is gradually adjusted in the above-mentioned adjustment procedure. The gaps g ₁ and g ₂ are eliminated by gradually moving the input rod 11 forward by the reaction, and then the stopper plate 2 is moved backward.
Input rod screw part 1 of nut 27 that rotates integrally with 6
The screwing position relative to 1a, therefore the stopper plate 2
6 is fixed with a lock nut 28.

To explain the operation during this time, as the input rod 11 moves forward due to the movement of the mounting position of the stopper plate 26, the first valve body ₁₄₁ is seated on the first valve seat ₁₃₁ , and the second valve seat ₁₃₂ is seated on the second valve body. 14 When you leave ₂ ,
Communication between the two working chambers A and B is cut off, and the second working chamber B communicates with the atmosphere inlet 5 through the side hole 19 and the through hole 15, and the outside air filtered by the air filters 20 and 20' is released. As a result, the pressure in the second working chamber B becomes higher than that in the first working chamber A, and the diaphragm 2 and the booster piston 6 move forward against the return spring 7 due to the pressure difference between them. Then, the output rod 21 is advanced via the reaction lever 25 and the reaction plate 24, and when the output rod 21 comes into contact with the piston 34, the stopper plate 26 is moved forward from the input rod 1.
1 to stop the input rod 11 from moving forward. Then, the second valve body ₁₄₂ , which is urged forward by the valve spring 17, catches up with the second valve seat ₁₃₂ and seats on it, as shown in FIG. While the pressure higher than that in working chamber A remains, the second
Since a neutral state of the control valve 4 is obtained in which the working chamber B is not communicated with either the first working chamber A or the atmosphere, the booster piston 6 can be stopped with the output rod 21 in contact with the working piston 34. , the stop position of the input rod 11 at this time becomes the normal retraction limit. The balance of the forces applied to the booster piston 6 at this time is the balance between the forward force of the booster piston 6 due to the pressure difference between the working chambers A and B and the elastic force of the return spring 7. Also, at this stage, the stopper ring 50 is naturally spaced forward from the booster piston 6 by the gap _g1 .

In addition, if the gap _g3 between the piston cup 36 and the relief hole 38 in the brake master cylinder M is larger than necessary due to a machining error, the stopper plate 2
By adjusting the mounting position of the piston 6, the input rod 11 can be further advanced to advance the piston 34 appropriately, thereby appropriately narrowing the distance _g3 .

After the retraction limit of the input rod 11 is properly adjusted in this way, when the input rod 11 is moved forward by stepping on the brake pedal (not shown) to apply the brakes of the automobile, the second valve seat ₁₃₂ is immediately Atmospheric air is introduced into the second working chamber B away from the valve body ₁₄₂ , and the pressure difference generated between the working chambers A and B causes the booster piston 6 to move forward, and the output rod 21, which is already in contact with the piston 34, moves forward. immediately drives forward, so
The brake master cylinder M can be operated without delay when the brake pedal is depressed. During this time, a part of the thrust of the output rod 21 is fed back to the control piston 10 and therefore to the input rod 11 via the reaction lever 25, and the operator can determine the magnitude of the thrust of the output rod 21 from the magnitude of the reaction force. can be sensed.

Next, the neutral state of the control valve 4 during operation of the brake master cylinder M, that is, the second working chamber B
When the depression force of the brake pedal is released from a state in which the brake pedal is disconnected from both the first working chamber A and the atmosphere, the input rod 11 is
However, first, the stopper ring 50 retreats until it comes into contact with the front surface of the booster piston 6, and as a result, the first valve body ₁₄₁ separates from the first valve seat ₁₃₁ , and the two working chambers A,
When B communicates with each other and the pressure difference between them disappears, the booster piston 6 moves due to the elastic force of the return spring 7.
It retreats together with the input rod 11. and input rod 11
However, when the stopper plate 26 reaches the normal retraction limit where it comes into contact with the booster shell end wall 1b, the booster piston 6 slightly passes the normal retraction position shown in _FIG . At the same _time , the second valve body ₁₄₂ is slightly spaced apart from the second valve seat ₁₃₂ to introduce atmospheric pressure into the second working chamber B. As a result, the booster piston 6 moves forward again until the control valve 4 reaches the neutral state, attains the aforementioned force balance state, and then stops. In this way, the booster piston 6, the output rod 21, and the piston 34 can also return to the same positions as before the brake pedal was depressed.

FIG. 4 shows another embodiment of the present invention, which is a rear extension tube 1a connected to the rear wall of the booster shell 1.
The booster shell 1 is press-molded separately from the booster shell 1, and is integrally held between the booster shell 1 and the automobile body F to which it is attached.Other constructions are the same as those of the previous embodiment.

As described above, according to the present invention, a rear extension tube into which an input rod is inserted is provided in series on the rear wall of the booster shell, an inward flange is formed at the rear end of the extension tube, and the inward flange is A central opening is formed as an air inlet port communicating with the second working chamber via a control valve, and the input rod engages with the inner surface of the inward flange to restrict the retraction limit of the input rod. The boss portion of the stopper member that protrudes toward the atmospheric air inlet port is screwed in a position-adjustable manner, and a lock nut is adjacent to the rear side of the stopper member and fixes the adjusted position of the stopper member with respect to the input rod. Since it is screwed into the input rod externally, the fixing position of the stopper member to the input rod can be adjusted as appropriate when the booster is not in operation, and by adjusting the movement, the output rod and the operated device connected thereto can be adjusted as appropriate. Not only can the play with the actuated part of the input rod be eliminated, but also the invalid stroke of the input rod during transition from the aforementioned backward switching state to the forward switching state can be reduced to zero or a small amount. The forward operation allows the actuated device to be actuated immediately, and the responsiveness of the actuated device can be improved.

In particular, when adjusting the movement of the stopper member relative to the input rod, it is sufficient to simply loosen the lock nut and rotate the stopper member relative to the input rod, and the boss of the stopper member protrudes toward the atmosphere inlet. Since the lock nuts are located outside the air inlet and can be easily operated from the outside, there is no need to separate the booster from the actuated device, and the movement of the stopper member can be easily adjusted. Work can be done extremely efficiently and easily. Furthermore, the movement adjustment mechanism for the stopper member can be achieved by simply screwing the stopper member and lock nut onto the input rod, or by forming a threaded portion on the rear extension tube side or by specially screwing an adjustment plate. Since there is no need to do this, the structure is simple and can contribute to cost reduction. Moreover, when the input rod moves forward, the stopper member immediately separates from the inward flange, so the opening degree of the air inlet port increases and air can be efficiently introduced into the second working chamber.
Even with the special provision of the stopper member, the responsiveness of the booster does not deteriorate.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional side view of an embodiment of the device of the present invention;
FIG. 2 is a sectional view taken along the line 2, FIG. 3 is a longitudinal sectional side view of the main part of the device shown in FIG. FIG. 1... Booster shell, 1a... Extension tube, 1b... Flange, 4... Control valve, 5... Atmospheric inlet, 6... Booster piston, 11... Input rod, 26, 27... Stopper plate and lock nut constituting the stopper member, 27 , 29...Nut and boss constituting the boss portion, S...Boosting device.

Claims (1)

[Claims] 1 A booster piston 6 whose front side is connected to the output rod 21 and is constantly urged in the backward direction by a return spring 7 is housed in the booster shell 1, and a negative pressure source is always connected to the front and rear sides of the booster piston 6. A first working chamber A communicates with the booster piston 6, and a second working chamber B whose communication with the first working chamber A or the atmosphere is switched and controlled via a control valve 4 described later is formed.
and the input rod 11 connected to the input rod 11 so as to be movable back and forth, so that a pressure is applied between the first and second working chambers A and B to cause the booster piston 6 to follow the movement of the input rod 11 when the input rod 11 moves. In a negative pressure booster comprising a control valve 4 that generates a difference, a rear extension cylinder 1a into which the input rod 11 is inserted is connected to the rear wall of the booster shell 1, and the extension cylinder 1a
An atmosphere inlet 5 having an inward flange 1b formed at its rear end and communicating a central opening of the inward flange 1b with the second working chamber B via the control valve 4.
Further, a boss of the stopper members 26 and 27 that engages with the inner surface of the inward flange 1b to restrict the retraction limit of the input rod 11 and protrudes toward the atmospheric air inlet 5 is formed on the input rod 11. A lock nut 28 is provided adjacent to the rear side of the stopper members 26, 27 to fix the adjusted position of the stopper members 26, 27 with respect to the input rod 11. It is screwed into the input rod 11,
Negative pressure booster.