JPH0427061B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Object of the Invention (1) Industrial Field of Application The present invention provides a booster shell with a partition plate that partitions the inside of the booster shell into a front shell chamber and a rear shell chamber. A rear booster piston that divides the rear shell chamber into a front negative pressure chamber and a rear working chamber is fixed to the valve cylinder, which is supported by the rear wall so as to be slidable back and forth, and outputs an output via a reaction force mechanism. A front booster piston that divides the front shell chamber into a front negative pressure chamber and a rear working chamber is connected to the output rod, and both negative pressure chambers are connected to a negative pressure source; The valve cylinder is a tandem negative pressure booster equipped with an input rod that can move forward and backward, and a control valve that connects both working chambers to the atmosphere and both negative pressure chambers according to the forward and backward movement of the input rod. Regarding.

(2) Conventional technology This type of negative pressure booster, for example,
This is already known as disclosed in Japanese Patent No. 10231.

(3) Problems to be solved by the invention In the conventional tandem type negative pressure booster, the output piston of the reaction force mechanism fitted to the output rod can be slid tightly between the boss of the front booster piston and the valve cylinder. If there is misalignment between the output rod and the driven member pushed by it due to machining or assembly errors, the output rod and the front booster piston and A prying force is generated between each part and the valve cylinder, which increases the frictional resistance of the sliding surfaces of each part, causing a disadvantage of causing a loss of input.

The present invention has been made in view of the above circumstances, and even if there is misalignment between the output rod and its driven member, it can be absorbed and the output rod, front booster piston, and valve cylinder can be aligned. To provide a tandem type negative pressure booster with a simple structure that prevents generation of prying force between the two and contributes to miniaturization and improved durability of a reaction force mechanism.

B. Structure of the Invention (1) Means for Solving Problems In order to achieve the above object, the present invention supports a front booster piston so as to be slidable back and forth on a valve cylinder so as to be independent from a reaction force mechanism. , the output rod is swingably connected to the reaction force mechanism, and the front abutment plate connected to the output rod and the rear abutment plate connected to the front booster piston are slidably connected to each other. Along with contacting
The contact surfaces of both contact plates are each formed into a spherical surface centered on the center of oscillation of the output rod, and a backward force is applied to the front and rear booster pistons between the front contact plate and the front wall of the booster shell. It is characterized by interposing a return spring for applying the force.

(2) Effect According to the above configuration, when misalignment occurs between the output rod and its driven member, the output rod swings against the reaction force mechanism, and at the same time, the output rod swings to allow the swing. Since the front abutment plate of the booster piston slides with the rear abutment plate of the front booster piston, the misalignment is absorbed.

In addition, since the front booster piston can slide back and forth on the valve cylinder, the reaction force mechanism does not receive the operational reaction force of the front booster piston, but only receives the operational reaction force of the rear booster piston. The load is reduced.

Since the spring force of the return spring is transmitted to the output rod and reaction force mechanism via the front abutment plate, even when the negative pressure booster is assembled alone, the reaction force mechanism and output rod will not fall out of the booster shell. This, together with the spherical contact between the front and rear abutment plates, restricts the lateral movement of the output rod.

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

In FIG. 1, a brake master cylinder M operated by the booster B is attached to the front surface of a booster shell 1 of a tandem negative pressure booster B. As shown in FIG.

The booster shell 1 includes a pair of front and rear shell halves 1a, 1b whose opposite ends are connected to each other, and is sandwiched between the two shell halves 1a, 1b so that the inside of the booster shell 1 is divided into a front shell chamber 2 and a rear shell chamber. 3, and a partition wall plate 1c that partitions the rear shell half body 1b into
is supported by a vehicle body (not shown).

The front shell chamber 2 includes a front booster piston 4 housed therein so as to be able to reciprocate back and forth, and a front diaphragm which is superimposed and bonded to the rear surface and sandwiched between the front shell half 1a and the partition plate 1c. 5, the rear shell chamber 3 is divided into a front negative pressure chamber 2a and a rear working chamber 2b, and the rear booster piston 6 is housed in the rear shell chamber 3 so as to be able to reciprocate back and forth.
A rear diaphragm 7 is polymerized and bonded to the rear surface and is fixed together with the partition plate 1c between the shell halves 1a and 1b, dividing the chamber into a negative pressure chamber 3a on the front side and an operating chamber 3b on the rear side.

A valve cylinder 8 made of synthetic resin is fixed to the center of the rear booster piston 6, and this valve cylinder 8 is attached to the partition wall plate 1.
c is slidably supported via the bush 9 and the seal member 10, and the rear shell half 1b
is slidably supported via a bush 12 and a seal member 13 at a rear extension 11 of the housing.

The front booster piston 4 is equipped with a cylinder shaft 14 whose tip extends rearward, and this cylinder shaft 14 is slidable relative to the valve cylinder 8 through a guide hole 15 that is open to the front end surface of the valve cylinder 8. inserted into.

A sealing member 16 is attached to the outer circumferential groove 17 of the cylinder shaft 14 so as to be slidably in close contact with the inner circumferential surface of the guide hole 15 . Therefore, the cylinder shaft 14 can slide and swing while maintaining airtightness between it and the guide hole 15, thereby reducing the prying force caused by mutual tilting of the front booster piston 4 and the valve cylinder 8. Occurrence can be prevented.

The front negative pressure chamber 2a is connected to a negative pressure source (not shown) (for example, the inside of an intake manifold of an internal combustion engine) via a negative pressure introduction pipe 19, and is connected to a rear negative pressure source via a first bifurcated port 20 of the valve cylinder 8. It communicates with the pressure chamber 3a. Further, the front and rear working chambers 2b and 3b are communicated with each other via a second bifurcated port 21 of the valve cylinder 8, and the front and rear negative pressure chambers 2a and 3a are connected to each other by a control valve 22.
and an atmospheric air inlet 23 opened in the end wall 11a of the rear extension 11.

Inside the valve cylinder 8, there is an input rod 25 connected to the brake pedal 24, and the control valve 2 controlled by the input rod 25.
2 is provided as follows. That is, the partition wall 8a formed in the middle part of the valve cylinder 8 is provided with a small cylinder 26 that opens at the center of the rear surface, and the valve piston 28 is slidably fitted into the small cylinder 26. This valve piston 28
is a stepped portion 29 connected to the open end of the small cylinder hole 26.
A flange 28a facing the flange 28a is formed on the outer periphery of the intermediate portion. A front end of an output rod 25 passing through the atmosphere inlet 23 is swingably connected to the valve piston 28 .

An annular first valve seat 30 ₁ is provided at the rear end of the partition wall 8a.
An annular second valve seat 3 is formed and surrounded by the second valve seat 3.
0 ₂ is formed on the rear end surface of the valve piston 28, and a valve body 31 that cooperates with these valve seats 30 ₁ and 30 ₂ is attached to the valve cylinder 8.
located within. The valve body 31 is made of rubber and has a cylindrical shape with both front and rear ends open.The rear end, i.e., the base end 31a, is held by a holding cylinder 32 fitted to the inner peripheral surface of the valve cylinder 8. 8 is maintained in close contact with the inner peripheral surface. This valve body 31 has the base end portion 31a.
Thin flexible portion 31 bent radially inward from
b, and a thick valve portion 31c continuous to the front end of the flexible portion 31b, and the valve portion 31c is arranged to face the first and second valve seats 30 ₁ and 30 ₂ .

The valve portion 31c can be moved back and forth by deforming the flexible portion 31b, and is seated on the first and second valve seats 30 ₁ and 30 ₂ when moving forward, and is received at the front end of the holding cylinder 32 when retreating. It can be stopped.

An annular reinforcing plate 33 is embedded in the valve portion 31c,
A valve spring 34 is provided between this and the output rod 25 to urge the valve portion 31c toward both valve seats 30 ₁ and 30 ₂ .

On the inner surface of the valve cylinder 8, one end of the first bifurcated port 20 is located outside the first valve seat ₃₀₁ , and one end of the first bifurcated port 20 is located outside the first valve seat 301.
₁ , one end of the second bifurcated port 21 is opened.

Further, the inside of the second valve seat 30 ₂ communicates with the atmosphere inlet 23 through the hollow portion of the valve body 31 and the holding cylinder 32 .

Thus, the valve body 31, the valve spring 34, and the first valve seat 30
The control valve 22 is constituted by _{the first} and second valve seats ₃₀₂ .

Between the input rod 25 and the holding cylinder 32, the input rod 25
A return spring 35 is provided that urges the rear end toward its retraction limit.

The retraction limit of the input rod 25 is determined by the rear extension point 11 of the stopper plate 36 screwed onto the input rod 25 so as to be adjustable forward and backward.
It is regulated by coming into contact with the inner surface of the end wall 11a. Therefore, by rotating the stopper plate 36, the screwing position between the stopper plate 36 and the input rod 25 changes, so that the retraction limit of the input rod 25 can be adjusted back and forth. To fix the stopper plate 36 after this adjustment,
This is done by tightening a lock nut 37 which is similarly screwed onto the input rod 25. The stopper plate 36 includes
A ventilation hole 38 is provided to prevent this from blocking the air inlet 23.

An air filter 39 is attached to the valve cylinder 8 so as to surround the input rod 25 for filtering the air taken into the valve cylinder 8 from the atmosphere inlet 23 . This air filter 39 has appropriate flexibility so as not to impede relative displacement between the input rod 25 and the valve cylinder 8.

The partition wall 8a of the valve cylinder 8 is provided with a large cylinder hole 27 that opens at the center of its front surface, and the large cylinder hole 27 and the small cylinder 26 having a smaller diameter are provided.
And they have a depth that communicates with each other deep within them. A rubber elastic piston 40 whose rear end face faces the valve piston 28 is tightly fitted into the large cylinder hole 27, and an output piston 41 that comes into contact with the front surface of the elastic piston 40 is loosely fitted into the large cylinder hole 27. An output rod 43 connected to the piston 42 of the brake master cylinder M is press-fitted to the front end of the brake master cylinder 41 . This output rod 43 can swing relative to the valve cylinder 8 by loosely fitting the output piston 41 into the large cylinder hole 27 and making the loosely fitting part of the piston 41 as thin as possible. The center is indicated by the symbol O. Thus, the valve piston 28, the elastic piston 40, and the output piston 41 constitute a reaction force mechanism 44.

A front abutment plate 45 extending toward the cylinder shaft 14 is sandwiched between the output rod 43 and the output piston 41, and a rear abutment plate 4 abuts against the rear surface of the front abutment plate 45.
7 is integrally connected to the rear end of the cylinder shaft 14. These front and rear contact plates 45 and 47 have respective contact surfaces.
f ₁ and f ₂ are formed to form spherical surfaces centered on the oscillation center O, and are capable of sliding relative to each other.

A return spring 46 is provided between the front contact plate 45 and the front shell half 1a of the booster shell 1 for applying a retraction force to the front and rear booster pistons 4 and 6.
is compressed, so that the spring force of the spring 46 is applied to the output rod 43 via the front abutting plate 45 to the reaction force mechanism 4.
4, even when the negative pressure booster B is assembled alone, the reaction force mechanism 44 and the output rod 43 are prevented from falling out of the booster shell 1, and the front and rear contact plates 45, 47 are prevented from falling off from each other. Coupled with the spherical contact, the lateral movement of the output rod 43 is restricted, and the reaction force mechanism 44 and the output rod 43 can be reliably held at a fixed position within the booster shell 1.

A return spring 46 is compressed between the front abutment plate 45 and the front wall of the booster shell 1. Therefore,
This return spring 46 is connected to the front and rear contact plates 45 and 47.
A retraction force is applied to the front booster piston 4 via the front booster piston 4, and a retraction force is also applied to the rear booster piston 6 via the front abutment plate 45, the reaction force mechanism 44, and the valve cylinder 8.

The backward movement of the rear booster piston 6 is regulated by a large number of protrusions 7a on the rear surface of the rear diaphragm 7 coming into contact with the rear wall of the booster shell 1, but the front diaphragm 5 does not touch the bulkhead plate 1c even during its backward movement. Do not touch.

Next, the operation of this embodiment will be explained. First, when the negative pressure booster B is at rest, as shown in Fig. 1,
The input rod 25 is positioned after retracting, and the control valve 22 has the valve portion 31c seated on the first and second valve seats 30 ₁ and 30 ₂ to connect both the front and rear working chambers 2b and 3b to both the negative pressure chambers 2.
The control valve 22 is in a neutral state where it is disconnected from both the negative pressure chambers 2a and 3a and the atmospheric air inlet 23. Negative pressure is stored, and the negative pressure appropriately diluted with the atmosphere is maintained in both working chambers 2b and 3b. In this way, a slight forward force is applied to the front and rear booster pistons 4 and 6 due to the pressure difference generated between the negative pressure chamber 2a and the working chamber 2b at the front, and between the negative pressure chamber 3a and the working chamber 3b at the rear. ,
These forward forces are balanced with the elastic force of the return spring 46, so that both booster pistons 4, 6 are stopped when they have advanced slightly from the retraction limit.

Now, when the brake pedal 24 is depressed to brake the vehicle and the input rod 25 and the valve piston 28 are moved forward, the second valve seat ₃₀₂ immediately separates from the valve portion 31c since the valve cylinder 8 is initially immobile. The working chambers 2b and 3b are communicated with the atmosphere inlet 23. As a result, the atmosphere flows from the atmosphere inlet 23 to the second valve seat 30 ₂
and both working chambers 2b through the second bifurcated port 21,
3b, and makes the chambers 2b, 3b have a higher pressure than the negative pressure chambers 2a, 3a, so a large forward force is obtained based on the pressure difference between them, and both booster pistons 4, 6 are moved by the force of the return spring 46. The piston 42 of the brake master cylinder M is driven forward via the output rod 43. In this way, the brake master cylinder M can be operated without delay when the brake pedal 24 is depressed, and the vehicle can be braked.

During such braking, the valve piston 28 moves forward together with the input rod 25 and comes into contact with the elastic piston 40, but the elastic piston 40 expands toward the small cylinder hole 26 due to the reaction force of the rear booster piston 6. Since the valve piston 28 is deformed and part of the reaction force is applied to the valve piston 28, the force is fed back to the brake pedal 24 side via the valve piston 28 and the input rod 25. Due to the action of the reaction force mechanism 44, the driver can sense the output of the output rod 43, that is, the magnitude of the braking force.

In this case, the reaction force mechanism 44 does not receive the operational reaction force of the front booster piston 4, but only receives the operational reaction force of the rear booster piston 6, so that the valve piston 2
8 and the elastic piston 40 are fitted into the small cylinder hole 26 and the large cylinder hole 27, respectively. can be reduced to increase its durability.

When the output of the output rod 43 exceeds the boosting limit point due to an increase in the pedal force applied to the brake pedal 24, that is, the input to the input rod 25, the valve piston 28 whose tip abuts against the elastic piston 40 is moved to the flange 28 at the intermediate portion.
a is also brought into contact with the stepped portion 29 of the valve cylinder 8, so that the entire input is transferred to the output rod 43 via the valve piston 28, the valve cylinder 8, the elastic piston 40, and the output piston 41.
As a result, the sum of the forward force due to the pressure difference between the booster pistons 4 and 6 and the forward force due to the input is output from the output rod 43.

By the way, in such a negative pressure booster B and brake master cylinder M, the output rod 43 and
When misalignment occurs between the output piston 41 and the driven member piston 42, the output piston 41 deforms the elastic piston 40 and oscillates together with the output rod 43 around the oscillation center O. The front abutment plate 45 of the output rod 43 is connected to the rear abutment plate 47 of the front booster piston 4 to allow the action.
slide against. Since the misalignment is absorbed by the smooth swinging action of the output rod 43, no prying force is generated in each part, and the forward force of both booster pistons 4 and 6 is transferred to the master cylinder M via the output rod 43. can be smoothly transmitted to the piston 42 of.

Next, when the pedal force on the brake pedal 24 is released, the input rod 25 moves back together with the valve piston 28 due to the elastic force of the return spring 35, and the second valve seat 3
0 ₂ is seated on the valve part 31c of the valve body 31, and the valve part 31c is separated from the first valve part ₃₀₁ by a large distance, so that both working chambers 2b and 3b are connected to both negative pressure chambers 2a and 3.
a, the pressure difference between the front and rear of each booster piston 4, 6 disappears immediately, and therefore both booster pistons 4, 6 move back with the elastic force of the return spring 46, releasing the operation of the brake master cylinder M. I will do it. Then, when the input rod 25 returns to the retraction limit where the stopper plate 36 comes into contact with the partition wall 11a of the extension tube 11, the rear booster piston 6 temporarily pushes the protrusion 7a of the rear diaphragm 7 into the booster shell, as shown in FIG. 1 returns to the retraction limit where it comes into contact with the rear wall of 1, and this time the first valve seat ₃₀₁ is seated on the valve part 31c, and the valve part 31c is slightly separated from the second valve seat ₃₀₂ , so that both working chambers are closed again. Atmospheric air is introduced into 2b and 3b, and due to the resulting pressure difference, both booster pistons 4 and 6 move forward a little so as to eliminate the small gap between the second valve seat ₃₀₂ and the valve part 31c. The control valve 22 is brought to its initial neutral state. In this way, the negative pressure diluted with the atmosphere is maintained in both working chambers 2b and 3b, and the negative pressure booster B enters the rest state as shown in FIG.

C. Effects of the Invention As described above, according to the present invention, the output rod is swingably connected to the reaction force mechanism, and the front abutment plate is connected to the output rod and the front booster piston is connected to the reaction force mechanism. The rear abutment plate and the rear abutment plate are slidably abutted against each other, and the abutment surfaces of both abutment plates are each formed into a spherical surface centered on the swing center of the output rod, so that the output rod and its operated Even if there is a misalignment between the input rod and the input rod, this can be absorbed by the smooth swinging action of the output rod, preventing the generation of prying force, and the input rod input can be accurately output without loss. It can be transmitted to the rod.

In addition, since the front booster piston is supported by the valve cylinder so that it can slide back and forth in order to be independent from the reaction force mechanism, the reaction force mechanism does not receive the operational reaction force of the front booster piston, but only the operational reaction force of the rear booster piston. , the load on the reaction force mechanism is reduced,
This can contribute to miniaturization and improved durability.

Furthermore, a return spring for applying a retraction force to the front and rear booster pistons is interposed between the front abutment plate and the front wall of the booster shell, so that the spring force of the spring is transferred through the front abutment plate. The force is transmitted to the output rod and reaction mechanism, which prevents the reaction force mechanism and output rod from falling out of the booster shell even when the negative pressure booster is assembled individually. Together with the spherical contact, it is possible to restrict the lateral movement of the output rod, and therefore the output rod and the reaction force mechanism can be reliably held at a fixed position within the booster shell. Moreover, since the return spring of the booster piston can also be used as such a holding means,
This can contribute to the simplification of the structure.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional side view of a tandem negative pressure booster in a resting state, and FIG. 2 shows a state immediately before the booster finishes operating and returns to its resting position. It is a partial vertical side view shown. B...Negative pressure booster, M...Master cylinder, O...
Swing center, f ₁ , f ₂ ... contact surface, 1 ... booster shell, 1c ... bulkhead plate, 2, 3 ... front and rear shell chambers,
2a, 3a...front, rear negative pressure chamber, 2b, 3b...front,
Rear working chamber, 4, 6...front, rear booster piston, 8...valve cylinder, 22...control valve, 25...input rod, 4
3... Output rod, 44... Reaction force mechanism, 45... Front abutment plate, 46... Return spring, 47... Rear abutment plate.

Claims (1)

[Claims] 1. The booster shell 1 is provided with a partition plate 1c that partitions the inside thereof into a front shell chamber 2 and a rear shell chamber 3, and a valve cylinder 8 supported on the rear wall of the booster shell 1 so as to be slidable back and forth is provided with a rear wall plate 1c. A rear booster piston 6 that partitions the shell chamber 3 into a negative pressure chamber 3a on the front side and an operating chamber 3b on the rear side is fixedly installed, and an output rod 43 is connected via a reaction force mechanism 44.
3, a front booster piston 4 that divides the front shell chamber 2 into a front negative pressure chamber 2a and a rear working chamber 2b is connected, and both negative pressure chambers 2a and 3a are connected to a negative pressure source, The valve cylinder 8 has an input rod 25 that can move forward and backward, and both working chambers 2b and 3 are opened in accordance with the forward and backward movement of the input rod 25.
In the tandem type negative pressure booster, a control valve 22 is installed to switch the control valve 22 between the atmosphere and the negative pressure chambers 2a, 3a. An output rod 43 is swingably connected to a reaction force mechanism 44, and a front abutment plate 45 is connected to the output rod 43, and a front booster piston 4 is connected to the front booster piston 4. The rear abutment plate 47 is slidably abutted against each other, and the abutment surfaces f ₁ and f ₂ of both abutment plates 45 and 47 are made into spherical surfaces centered on the oscillation center O of the output rod 43. The front abutment plate 45 and the booster shell 1 are formed respectively.
Between the front wall and the front and rear booster pistons 4 and 6
A tandem negative pressure booster characterized in that a return spring 46 is interposed for applying a retraction force to the tandem negative pressure booster.