JPS6231665B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a negative pressure booster that boosts the brake master cylinder of an automobile using negative pressure, and in particular to a booster shell that is housed inside a booster shell attached to a vehicle body so as to be able to reciprocate back and forth. A first working chamber connected to a negative pressure source by a piston, and a second working chamber whose communication with the first working chamber or the atmosphere is switched and controlled via a control valve, and connected to the booster piston so as to be freely retractable. The input rod is connected to the control valve so that when the input rod moves forward, a pressure difference is generated between the two working chambers to cause the booster piston to follow the movement. The present invention relates to an improvement in a negative pressure booster which is connected via a tie rod passing through the booster piston, and includes sealing means between the tie rod and the booster piston to allow the piston to operate.

The above-mentioned booster device can avoid the effect of this load on the booster shell by transmitting the forward thrust load received from the output side to the vehicle body via the tie rod, so the booster shell has a high enough rigidity to withstand the above load. This eliminates the need to provide weight, and it has the advantage that it can be molded from thin steel plate, synthetic resin, etc. to reduce its weight.

In the above device, the tie rod and the rear wall of the booster shell are connected by using bolts for attaching the booster shell to the vehicle body, thereby simplifying the structure and connecting the tie rod and the rear wall of the booster shell. The purpose is to ensure the airtightness of the area.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. S is a negative pressure booster, and its booster shell 1 is constructed by abutting and joining a pair of front and rear bowl-shaped bodies 1F, 1R, and each bowl-shaped body 1F and 1R are formed from lightweight thin steel plates or synthetic resin. The interior of this booster shell 1 includes a booster piston 2 housed therein so as to be able to reciprocate back and forth, and a piston diaphragm 3 whose inner circumference is fixed to the rear surface and whose outer circumference is clamped between the bowl-shaped bodies 1F and 1R.
It is divided into a first working chamber A at the front and a second working chamber B at the rear. 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 4, and the second working chamber B
is controlled by being alternately communicated with the first working chamber A or an atmosphere inlet 6 opened in the end wall 1b of the rear extension tube 1a of the booster shell 1 via a control valve 5 which will be described later.

The booster piston 2 is always urged in the backward direction, that is, toward the second working chamber B, by a return spring 7 contracted in the first working chamber A, and its backward limit is reached by a rib 3a formed protuberantly on the back surface of the piston diaphragm 3. It is regulated by coming into contact with the rear wall of the booster shell 1.

The booster piston 2 is integrally formed with a valve cylinder 8 projecting in the axial direction from the rear surface of its center portion, and is slidably supported on a flat bearing 9 provided in the extension cylinder 1a, and its rear end is connected to the atmosphere. It opens toward the introduction port 6.

The control valve 5 is configured in the valve cylinder 8 as follows.
That is, an annular first valve seat 10 ₁ is provided on the front inner wall of the valve cylinder 8.
A valve piston 12 connected to the input rod 11 and forming the front end thereof is slidably connected to the front part of the valve cylinder 8, and the first valve seat 1 is attached to the rear end of the valve piston 12.
An annular second valve seat 10 ₂ surrounded by 0 ₁ is formed.

A base end 13a of a cylindrical valve element 13 with both ends open is clamped to the inner wall of the valve cylinder 8 via a valve element holding cylinder 14 fitted into the valve cylinder 8. This valve body 13 is made of an elastic material such as rubber, and its base end 1
A thin-walled diaphragm 13b extends radially inward from 3a, and a thick-walled valve portion 13c is connected to the inner peripheral end of the thin-walled diaphragm _13b . Facing ₂ . Thus, the valve portion 13c can move back and forth by deforming the diaphragm 13b, and can also come into contact with the front end surface of the valve body holding cylinder 14.

An annular reinforcing plate 15 is embedded in the valve portion 13c, and a valve spring 16 acts on the annular reinforcing plate 15 to bias the valve portion 13c toward both valve seats 10 ₁ and 10 ₂ .

The outer part of the first valve seat ₁₀₁ is the booster piston 2
The intermediate portions of the first and second valve seats 10 ₁ and 10 ₂ are connected to the second working chamber B through another through hole 18, and the second valve seat 10
The inner part of ₂ is connected to the atmosphere inlet 6 through the inside of the valve body 13.
are in constant communication with each other.

The booster piston 2 is provided with a large-diameter hole 19 that opens at the center of its front surface, and a small-diameter hole 20 that opens at the inner end surface of the large-diameter hole 19.
An elastic piston 21 made of rubber or the like and an output piston 22 having the same diameter are sequentially slid into the small diameter hole 20, and a reaction piston 23 having a smaller diameter than the elastic piston 21 is slid into the small diameter hole 20.
0, the small shaft 12a protruding from the front end surface of the valve piston 12 is inserted to face the rear end surface of the reaction piston 23. The output piston 22 integrally has an output rod 22a that projects forward.

The input rod 11 is always urged in the backward direction by the return spring 24, and its retraction limit is determined by the movable stopper plate 25 screwed onto the input rod 11 when the rear extension cylinder 1a
It is regulated by coming into contact with the inside of the end wall 1b. If the movable stopper plate 25 is rotated, the screwing position between it and the input rod 11 changes, so that the retraction limit of the input rod 11 can be adjusted back and forth. After the adjustment, the movable stopper plate 25 is fixed by screwing a lock nut 26 which is also screwed onto the input rod 11. A vent hole 27 is provided in the stopper plate 25 to prevent it from blocking the atmosphere inlet 6.
to be drilled.

Filters 32 and 33 are attached to the outer end opening of the valve cylinder 8 to purify the air introduced from the atmospheric air inlet 6 and to be deformable so as not to interfere with the operation of the input rod 11.

The front and rear walls of the booster shell 1, that is, the opposite walls of the bowl-shaped bodies 1F and 1R, are connected via one or more tie rods 34 that penetrate the booster piston 2 and the piston diaphragm 3. Booster piston 2 penetrates
In order to seal the through hole 31 so as not to interfere with the operation of the piston 2, a rolling diaphragm 35 is stretched between the opposing peripheral surfaces of the booster piston 2 and the tie rod 34. It is preferable that the rolling diaphragm 35 is integrally molded with the piston diaphragm 3 as shown in the drawings, and that its fixed end is tightly fitted into an annular mounting groove 36 on the circumferential surface of the tie rod 34 to be fixed therein.

To explain specifically the connection structure between the tie rod 34 and the booster shell 1, the tie rod 34 integrally has a tightening bolt 37 that passes through the front wall of the booster shell 1, and is fitted and fixed to the base of the bolt 37. The front wall of the booster shell 1 and the mounting flange 40 of the brake master cylinder M superimposed on the front surface of the booster shell 1 are clamped by a flange member 38 that contacts the inner surface of the front wall of the booster shell 1 and a nut 39 that is screwed to the tip thereof. At that time, the annular seal member 42 is loaded into an annular groove 41 formed on the front surface of the flange member 38 so as to surround the bolt 37, and the annular seal member 42 is inserted between the bolt 37, the flange member 38, and the inner surface of the front wall of the booster shell 1. in airtight contact.
When the annular seal member 42 is arranged in this way, 1
The annular seal members 42 can prevent leakage in two paths: between the inner surface of the front wall of the booster shell 1 and the flange member 38 and between the flange member 38 and the bolt 37.

Further, one end 43a of a mounting bolt 43 for fixing the booster shell 1 to the front wall W of the vehicle interior is screwed into the rear end of the tie rod 34 through the rear wall of the booster shell 1 and tightened. Then the mounting bolt 43
A flange 44 is integrally protruded from the middle of the tie rod 34, and this cooperates with a flange 45 at the rear end of the tie rod 34 to clamp the rear wall of the booster shell 1. At that time, the tie rod 34 is attached so as to surround the bolt 43.
An annular seal member 47 is loaded into an annular groove 46 formed on the rear surface of the flange 45 of the bolt 4.
3. The flange 45 and the rear wall of the booster shell 1 are brought into airtight contact.

The mounting bolt 43 protruding from the rear surface of the booster shell 1 is passed through the front wall W of the vehicle interior, and a nut 52 is screwed onto its tip to fix the bolt 43 to the front wall W of the vehicle interior.

Thus, the booster shell 1 is attached to the front wall W of the vehicle interior via the tie rod 34 and the mounting bolt 43, and the brake master cylinder M is supported by the booster shell 1 via the tie rod 34.

In the vehicle interior, a brake pedal 55, which is pivoted 54 on a fixed bracket 53, is connected to the rear end of the input rod 11 of the booster S via an adjustment connection fitting 56. 57 is a return spring that biases the brake pedal 55 rearward.

Cylinder body 58 of brake master cylinder M
The rear end penetrates the front wall of the booster shell 1 and enters the first working chamber A, and the cylinder body 5
The output rod 22a of the booster S is opposed to the rear end of the operating piston 59 in the booster S.

Next, to explain the operation of this embodiment, the illustrated state shows the non-operating state of the booster.
The valve piston 12, the input rod 11, and the brake pedal 49, which are connected to each other, are returned to a predetermined retracted position where the movable stopper plate 25 abuts the fixed end wall 1b, and are held by the spring force of the spring 24, and the valve piston 12 is The front face of the valve part 13c is pressed through the second valve seat ₁₀₂ , and is moved back until it lightly contacts the front face of the valve body holding cylinder 14.
A slight gap g is formed between the valve seat ₁₀₁ and the valve portion 13c. Such a state can be easily obtained by adjusting the stopper plate 25 described above.

As described above, the first working chamber A, which constantly stores negative pressure, communicates with the second working chamber B via the through hole 17, the gap g, and the through hole 18, and the front opening of the valve part 13c is connected to the second valve. Since it is closed by the seat ₁₀₂ , the second
The negative pressure in the first working chamber A is transmitted to the working chamber B, and the air pressures in both working chambers A and B are balanced. Therefore, the booster piston 2 also occupies the illustrated retracted position by the elastic force of the return spring 7.

Now, if the brake pedal 55 is depressed to brake the vehicle and the input rod 11 and the valve piston 12 are moved forward, the valve portion 13c, which is urged forward by the valve spring 16, will move forward following the valve piston 12. Since the gap g between the first valve seat ₁₀₁ and the valve part 13c is extremely narrow as described above, the valve part 13c immediately seats on the first valve seat ₁₀₁ to establish communication between the working chambers A and B. At the same time, the second valve seat ₁₀₂ is closed to the valve part 13.
The second working chamber B is communicated with the atmosphere inlet 6 through the through hole 18 and the inside of the valve body 13, apart from the second working chamber B. Therefore, the atmosphere is quickly introduced into the second working chamber B, and the pressure in this chamber B becomes higher than that in the first working chamber A, and the pressure difference between the two chambers A and B causes the booster piston 2 to resist the return spring 7. Since the output rod 22a is moved forward via the elastic piston 21,
The operating piston 59 of the brake master cylinder M is driven forward, and the vehicle is braked.

When the actuating piston 59 is driven, a forward thrust load is applied to the cylinder body 58 as described above, but this load is transmitted to the vehicle body, that is, the front wall W of the vehicle interior via the tie rod 34, and is supported. . Therefore, the above-mentioned load does not act on the booster shell 1.

On the other hand, due to its advancement, the small shaft 12a of the valve piston 12 passes through the reaction piston 23 to the elastic piston 2.
1, a part of the reaction force is fed back to the brake pedal 55 side via the valve piston 12 due to the expansion deformation of the elastic piston 21 toward the reaction piston 23 side due to the actuation reaction force of the output rod 22a. This allows the driver to sense the output of the output rod 22a, that is, the braking force.

Next, when the depression force of the brake pedal 55 is released, the input rod 11 is moved backward due to the reaction force exerted on the valve piston 12 and the elastic force of the return spring 24, thereby causing the second valve seat ₁₀₂ to move toward the valve position. At the same time, the valve portion 13c is seated on the valve body holding cylinder 14.
The valve part 13c is brought into contact with the front surface of the input rod 1.
Compressive deformation occurs in the axial direction due to the retreating force of 1.
As a result, a gap larger than the initial gap g is formed between the first valve seat ₁₀₁ and the valve part 13c, so that the air pressures in both working chambers A and B are quickly balanced with each other through this gap. When the pressure difference disappears, the booster piston 2 moves backward by the elastic force of the return spring 7, and the rib 3a of the piston diaphragm 3 comes into contact with the inner surface of the rear wall of the booster shell 1 and stops. Then, when the input rod 11 comes into contact with the end wall 1b, the valve part 13c is released from the retreating force of the input rod 11 and returns to its original shape, so that the gap with the first valve seat ₁₀₁ is reduced to the small gap g again. It can be narrowed down.

As described above, according to the present invention, the mounting bolt 43
Since the front and rear walls of the booster shell 1, which is attached to the vehicle body, are connected via the tie rod 34 that passes through the booster piston 2, when the booster is activated, the front thrust load received from the load side is transferred to the vehicle body via the tie rod. The load can be transmitted and supported, and the effect of the above-mentioned load on the booster shell 1 can be avoided. Further, the rear end surface of the tie rod 34 is brought into contact with the inner surface of the rear wall of the booster shell 1 via a ring-shaped seal member 47, and a flange 44 that cooperates with the rear end of the tie rod 34 to clamp the rear wall of the booster shell 1 Since one end 43b of the mounting bolt 43, which is formed so as to have an intermediate part, is screwed into the tie rod 34 and tightened, the mounting bolt 43 and the tie rod 3
The tie rod 34 can be connected to the rear wall of the booster shell 1 at the same time as the tie rod 34 is connected to the rear wall of the booster shell 1, and the airtightness of the connection can be ensured. Therefore, it is easy to assemble, has a small number of parts, has a simple structure, and can be provided at low cost.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of one embodiment of the device of the present invention. A...First working chamber, B...Second working chamber, S...
Boost device, W...Front wall of the cabin as a vehicle body, 1...
...Booster shell, 2...Booster piston, 5
... control valve, 6 ... atmosphere inlet, 11 ... input rod, 34 ... tie rod, 35 ... rolling diaphragm as sealing means, 43 ... mounting bolt, 44 ... flange, 47 ... sealing member.

Claims (1)

[Claims] 1 The inside of the booster shell 1 fixed to the vehicle body W by the mounting bolts 43 is connected to the first working chamber A connected to the negative pressure source by the booster piston 2 housed therein so as to be able to reciprocate back and forth, and the first working chamber A through the control valve 5. The booster piston 2 is divided into a working chamber A and a second working chamber B whose communication with the atmosphere is switched and controlled.
The input rod 11 is connected to the control valve 5 so that when the input rod 11, which is movably connected to the control valve 5, moves forward, a pressure difference is generated between the working chambers A and B to cause the booster piston 2 to follow the movement. A seal means 35 is provided between the tie rod 34 and the booster piston 2 to allow the piston 2 to operate. In the provided negative pressure type booster, the rear end surface of the tie rod 34 is brought into contact with the inner surface of the rear wall of the booster shell 1 via the annular seal member 47, and the rear end of the tie rod 34 cooperates with the inner surface of the rear wall of the booster shell 1 to close the booster shell. The mounting bolt 4 is formed to have a flange 44 in the middle portion that clamps the rear wall of the mounting bolt 4.
A negative pressure booster characterized in that one end 43a of the tie rod 34 is screwed into the tie rod 34 and tightened.