JPS636392B2 - - 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, the outer peripheral edges of opposing front and rear walls are airtightly connected to each other. The booster shell is configured with a booster piston, which is connected to a negative pressure source by a booster piston housed inside the booster shell so as to be able to reciprocate back and forth.
When an input rod, which is divided into a working chamber and a second working chamber whose communication with the first working chamber or the atmosphere is switched and controlled via a control valve, moves forward and backward of the booster piston, The present invention relates to an improvement in a negative pressure booster in which the input rod is connected to the control valve so that a pressure difference for causing the booster piston to follow the action is generated between the two working chambers.

Generally, when such a booster is installed in an automobile, the rear wall of the booster shell is fixed to the vehicle body fixed wall, and the front wall of the booster shell supports the master cylinder. When hydraulic pressure is generated in the chamber, the forward thrust load applied to the master cylinder by the hydraulic pressure is supported by the vehicle body via the booster shell. Therefore, the booster shell must have sufficient rigidity to withstand the above thrust load, and conventionally it has been made of relatively thick steel plates or
It is made of AI alloy, etc., but the problem is that it is quite heavy.

The present invention was proposed in view of the above, and the front and rear walls of the booster shell are connected via a tie rod that passes through the booster piston, and the tie rod transmits the front thrust load to the vehicle body. In addition to reducing the weight of the shell, even when the tie rod is separated from the booster shell, the entire booster, including the seal structure of the first and second working chambers, can be maintained in a fully assembled state, thereby improving ease of assembly. It is an object of the present invention to provide the negative pressure type booster which is designed to improve the performance.

In order to achieve the above object, the present invention provides a negative pressure booster of the type described above, in which both front and rear ends of a sleeve that passes through the booster piston are sandwiched between opposing surfaces of the front and rear walls of the booster shell. A telescopic boot is stretched between the opposing peripheral surfaces of the sleeve and the booster piston, and a retractable boot is provided between the front end of the sleeve and the front wall, and between the rear end of the sleeve and the rear wall. A sealing member for airtight sealing is interposed between the sleeve and the booster shell, a master cylinder disposed adjacent to the front side of the shell, and a fixed wall disposed adjacent to the rear side of the shell. It is characterized in that the middle part of the tie rod for integral connection is inserted.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, S is a negative pressure booster, and the booster shell 1 is the outer periphery of the front and rear bowl-shaped bodies 1F and 1R as the front and rear walls. The bowl-shaped bodies 1F and 1R are made of 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 circumferential portion is fixed to the rear surface and whose outer circumferential portion is sandwiched between the bowl-shaped bodies 1F and 1R. This defines 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 a negative pressure introduction pipe 4, and the second working chamber B is in communication with the intake manifold (not shown) of the internal combustion engine, which is a negative pressure source. Communication is controlled alternately with the atmosphere inlet 6 opened in the end wall 1b of the steel plate rear extension tube 1a of the 1 working chamber A or the booster shell 1.

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 central portion, and is slidably supported by a synthetic resin flat bearing 9 integrally formed in the rear bowl-shaped body 1R. At the same time, a control valve 5 is arranged in the valve cylinder 8 whose rear end is opened toward the atmosphere inlet 6 as follows. That is,
An annular first valve seat 10 ₁ is formed on the front inner wall of the valve cylinder 8, and 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.
An annular second valve seat 10 _{2 surrounded by the first valve seat 10 1} is formed at the rear end of the valve piston ₁₂ .

A base end 13a of a cylindrical valve element 13 with both ends open is held on 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 molded from 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 this to urge 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
into the first working chamber A through a through hole 17, and an intermediate portion between the first and second valve seats 10 ₁ and 10 ₂ through another through hole 1
8 to the second working chamber B, and the second valve seat 10 ₂
The inner parts of the valve body 13 are in constant communication with the atmospheric air inlet 6 through the inside of the valve body 13.

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 of the same diameter are sequentially inserted into the small diameter hole 20, and a reaction piston 23 with 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 a return spring 24, and its retraction limit is reached by a movable stopper plate 25 screwed onto the input rod 11 when the rear extension cylinder 1
It is regulated by contacting the inside of the end wall 1b of a. Then, if the movable stopper plate 25 is rotated,
Since the screwing position between it and the input rod 11 changes, 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 tightening a lock nut 26 which is also screwed onto the input rod 11. A vent hole 2 is provided in the movable stopper plate 25 to prevent it from blocking the atmosphere inlet 6.
7 is drilled.

Filters 28 and 29 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.

A pair or multiple pairs of stepped through holes 30, 31 are bored in the front and rear walls of the booster shell 1, that is, the opposite walls of the front and rear bowl-shaped bodies 1F, 1R. Large diameter hole 30a located inside,
The front and rear ends of the sleeve 32 that pass through the booster piston 2 and the piston diaphragm 3 are respectively fitted into the inside of the sleeve 31a, and the sleeve 32 is inserted into both bowl-shaped bodies 1.
It will be sandwiched between F and 1R. At that time, the sleeve 32
Annular seal members 35 and 36 are loaded into respective annular grooves 33 and 34 formed in the fitting portions of both ends to maintain the space between the first and second working chambers A and B airtight from the outside.

In order to seal the through hole 37 of the booster piston 2 through which the sleeve 32 passes so as not to interfere with the operation of the piston 2, a rolling diaphragm 38 as a telescopic boot is provided between the opposing circumferential surfaces of the booster piston 2 and the sleeve 32. Stretch it. It is preferable that the rolling diaphragm 38 is integrally molded with the piston diaphragm 3 as shown in the figure, and that its fixed end is tightly fitted into an annular mounting groove 39 on the circumferential surface of the sleeve 32 and fixed therein.

A tie rod 40 is fitted into the sleeve 32, and the tie rod 40 interconnects the booster shell 1, the brake master cylinder M adjacent to the front side thereof, and the front wall W of the passenger compartment adjacent to the rear side. Link. To explain the connection structure in detail, the front and rear ends of the tie rod 40 protruding from the sleeve 32 are formed into tightening bolts 41 and 44, respectively, and a flange 46 is integrally formed at the base of the rear bolt 44. The flange 46 is overlapped with the mounting flange 1c of the rear extension tube 1a on the rear surface of the rear bowl-shaped body 1R, while
The front bolt 41 is passed through the mounting flange 43 of the brake master cylinder M, and the nut 42 is screwed into it and tightened. Thus, tie rod 40 is
Connects booster shell 1 and brake master cylinder M. Furthermore, when attaching the booster shell 1 to the front wall W of the vehicle interior, the bolts 44 at the rear are passed through the front wall W of the vehicle interior, the flange 46 is stacked on the front surface of the front wall W of the vehicle interior, and then the bolts 44 are inserted into the front wall W of the vehicle interior. Natsuto 45
Screw and tighten. In this way, the booster shell 1 is fixed to the front wall W of the vehicle compartment via the tie rod 40.

In the vehicle interior, a brake pedal 49, which is pivoted 48 on a fixed bracket 47, is connected to the rear end of the input rod 11 of the booster S via an adjustment connection fitting 50. 51 is a return spring that urges the brake pedal 49 rearward.

The rear end of the cylinder body 52 of the brake master cylinder M penetrates the front wall of the booster shell 1 and enters the first working chamber A, and the rear end of the working piston 53 in the cylinder body 52 is connected to a booster. S
The output rods 22a of the two are opposed to each other.

Next, to explain the operation of this embodiment, the illustrated state shows the non-operating state of the booster, and the valve piston 12, input rod 11 and brake pedal 49 which are connected to each other are connected to each other when the movable stopper plate 25 is fixed. The spring 2 returns to a predetermined retracted position in contact with the end wall 1b.
4, 51, and the valve piston 12 presses the front surface of the valve portion 13c via the second valve seat ₁₀₂ and retreats until it lightly contacts the front surface of the valve body holding cylinder 14. Thereby, a slight gap g is formed between the first valve seat ₁₀₁ and the valve portion 13c. Such a state can be easily obtained by adjusting the movable 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 through 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 seat. 10 ₂ , the negative pressure in the first working chamber A is transmitted to the second 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 49 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 10 ₁ and the valve part 13c is extremely narrow as described above, the valve part 13c immediately seats on the first valve seat 10 ₁ 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 53 of the brake master cylinder M is driven forward, and the vehicle is braked.

When the actuating piston 53 is driven, a forward thrust load is applied to the cylinder body 52 as described above, but this load is transmitted to and supported by the vehicle body, that is, the front wall W of the vehicle interior, via the tie rod 40. 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 49 side via the valve piston 12 due to the bulging 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 49 is released, the input rod 11 is moved back due to the reaction force applied to the valve piston 12 and the elastic force of the return spring 24, and the movable stopper plate 25 initially comes into contact with the end wall 1b. During this time, the valve portion 13c separates from the first valve seat ₁₀₁ to communicate between the working chambers A and B, and when the pressure difference between them disappears, the booster piston 2 is moved away from the return spring 7. The piston diaphragm 3 moves backward due to the elastic force, and the rib 3a of the piston diaphragm 3 comes into contact with the inner surface of the rear wall 1c of the booster shell 1 and stops.

As described above, according to the present invention, before facing each other,
A booster shell is formed by airtightly connecting the outer peripheral edges of the rear walls to each other, and a first working chamber connected to a negative pressure source by a booster piston housed in the booster shell so as to be able to reciprocate back and forth, and a control valve are connected to the inside of the booster shell. the first working chamber or a second working chamber whose communication with the atmosphere is switched and controlled, and when an input rod, which is movably provided opposite to the booster piston, moves forward, the booster piston is actuated in accordance with the forward movement of the input rod. In a negative pressure booster in which the input rod is connected to the control valve, the booster piston is placed between opposing surfaces of the front and rear walls of the booster shell so that a pressure difference is generated between the two working chambers. Both front and rear ends of the penetrating sleeve are clamped, and a telescopic boot is stretched between the facing circumferential surfaces of the sleeve and the booster piston, and between the front end of the sleeve and the front wall, and the rear end of the sleeve. A sealing member is interposed between the booster shell and the rear wall to airtightly seal the space between them, and the sleeve includes the booster shell, a master cylinder disposed adjacent to the front side of the shell, and a seal member disposed on the rear side of the booster shell. Since the middle part of the tie rod that connects the three adjacent fixed walls to each other is inserted, the large forward thrust load that the booster shell should receive from the master cylinder side is transferred through the tie rod. This allows the booster shell to be directly received by the fixed wall, reducing the load on the booster shell.Therefore, there is no need to provide the booster shell with high rigidity to withstand the above-mentioned thrust load. Since it can be constructed from a thin steel plate or the like, it is possible to achieve a significant weight reduction of the booster shell and, by extension, the booster.

Moreover, the entire booster including the seal structure of the first and second working chambers can be maintained in a fully assembled state with the tie rod separated from the booster shell, so that the booster itself can be assembled and the booster shell itself can be assembled. Inspection of the booster and assembly of the device to the master cylinder and fixed wall can be performed efficiently on separate lines, and even after assembly, the tie rod can be replaced without disassembling the booster itself. This can be done freely, and one type of booster can be used in combination with multiple types of tie rods of different lengths, giving a wide range of applications.

Moreover, since the sleeve has the function of a distance piece that maintains a constant distance between the front and rear walls of the booster shell, axial compression is created between the front and rear walls of the booster shell due to external force or negative pressure inside the shell. Even if a load is applied, the sleeve strongly resists the load and can effectively prevent deformation of the front and rear walls of the shell. Furthermore, even if the tie rod itself stretches somewhat due to the thrust load, it does not affect the sealing member between the front and rear ends of the sleeve and the front and rear walls of the shell, so that its sealing function can always be effectively exhibited.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of one embodiment of the device of the present invention. DESCRIPTION OF SYMBOLS 1... Booster shell, 1F... Front bowl-shaped body as a front wall, 1R... Rear bowl-shaped body as a rear wall, 2... Booster piston, 5... Control valve, 11... Input rod, 3
2... Sleeve, 35, 36... Seal member, 38...
Rolling diaphragm as a telescopic boot, 4
0... Tie rod, A... First working chamber, B... Second working chamber, M... Brake master cylinder as a master cylinder, S... Negative pressure booster, W... Vehicle compartment front wall as a fixed wall.

Claims (1)

[Claims] 1 A booster shell is formed by airtightly connecting the outer peripheral edges of the opposing front and rear walls to each other, and the first actuator is connected to a negative pressure source by a booster piston housed in the booster shell so as to be able to reciprocate back and forth. and a second working chamber whose communication with the first working chamber or the atmosphere is switched and controlled via a control valve, and when an input rod, which is movably provided opposite to the booster piston, moves forward, In a negative pressure booster in which the input rod is connected to the control valve, so that a pressure difference for the follow-up operation of the booster piston is generated between the two working chambers, there is a gap between the opposing surfaces of the front and rear walls of the booster shell. The front and rear ends of a sleeve passing through the booster piston are clamped, and a telescopic boot is stretched between the opposing circumferential surfaces of the sleeve and the booster piston, and the sleeve is inserted between the front end of the sleeve and the front wall, and A sealing member is interposed between the rear end of the sleeve and the rear wall to airtightly seal the space between them, and the sleeve includes the booster shell, a master cylinder disposed adjacent to the front side of the booster shell, A negative pressure booster in which the middle part of a tie rod is inserted to connect three fixed walls adjacent to each other on the rear side of the same shell.