JPS6340712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an assembly of a negative pressure booster and a master cylinder, which are mainly used to operate hydraulic brakes, clutches, etc. of automobiles, and in particular, a booster piston inside the booster piston, and a booster piston attached to the booster piston. A booster shell that accommodates a piston diaphragm whose inner peripheral end is bound is divided into a front bowl-shaped body and a rear bowl-shaped body, and the outer peripheral end of the piston diaphragm is sandwiched between opposing ends of the two bowl-shaped bodies. The present invention relates to an assembly in which a cylinder body of a master cylinder is disposed on the front surface of the front bowl-shaped body, and the booster piston is connected to an operating piston that slides on the cylinder body.

In the above assembly, the two bowl-shaped bodies and the cylinder body are connected by a tie rod that passes through the booster piston, and the tie rod receives the forward thrust load that acts on the cylinder body when the booster is activated. Types that reduce the load on the shell are conventionally known, but
The present invention provides a device of this type that has a simple structure that allows quick and accurate assembly work of the device.
An object of the present invention is to provide an assembly of a booster and a master cylinder.

In order to achieve the above object, the present invention fixes the rear ends of at least two tie rods that pass through the booster piston and are parallel to each other to the rear bowl-shaped body, and also connects the front parts of the tie rods with a connecting plate. The connecting plate is brought into contact with the inner surface of the front bowl-shaped body, and the front bowl-shaped body and the cylinder body are fixed to the front ends of each of the tie rods, and the opposite ends of both of the bowl-shaped bodies are The present invention is characterized in that positioning means is provided between the parts to permit relative movement in the axial direction but restrict relative movement in the circumferential direction.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a booster shell 1 of a negative pressure booster S is constructed from a pair of front and rear bowl-shaped bodies 1F and 1R molded from lightweight thin-walled steel plate or synthetic resin. A plurality of claw pieces 1a protruding from the opening of the rear bowl-shaped body 1R at equal intervals on the circumference are attached to the front bowl-shaped body 1R.
The two bowl-shaped bodies 1F and 1R are mutually positioned by engaging with a plurality of notches 1b formed at equal intervals on the circumference in the openings of the bowl-shaped bodies 1F and 1R. Therefore, the claw piece 1a and the notch 1
b cooperate with each other to constitute a positioning means of the present invention that allows relative movement in the axial direction between the opposing ends of both bowl-shaped bodies 1F and 1R, but restricts relative movement in the circumferential direction. Both bowl-shaped bodies 1F and 1R are connected between their front and rear opposing walls via a plurality of (two in the illustrated example) tie rods 30 that are parallel to each other. The connection structure between the booster shell 1 and the tie rod 30 will be described later.

The inside of the booster shell 1 has a booster piston 2 accommodated therein so as to be able to reciprocate back and forth, and a piston diaphragm 3 made of a flexible material such as rubber that is in contact with the rear surface, and a first working chamber A at the front and a first working chamber A at the rear. It is divided into a second working chamber B.

As shown in FIG. 2, the piston diaphragm 3 has an annular shape as a whole, and annular beads 3a and 3b are integrally formed on both the inner and outer peripheral edges, and the outer peripheral bead 3a is connected to the two bowl-shaped bodies. 1F,1
The inner peripheral bead 3b is inserted into the annular groove 1c formed in the fitting portion of
Fit each into a.

The first working chamber A is always in communication with an 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 connected through a control valve 5, which will be described later. The air inlet 6 is alternately controlled to communicate with the first working chamber A or with the atmosphere inlet 6 opened in the end wall 1e of the rear extension tube 1d of 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 protrusion 3e formed protrudingly on the back surface of the piston diaphragm 3. It is regulated by coming into contact with the inner surface of the rear wall of the booster shell 1.

The booster piston 2 and the piston diaphragm 3 have a through hole 3 through which the tie rod 30 passes.
1 and 32 are provided, respectively, and the through hole 32 is opened at the front surface of the piston diaphragm 3 which can be separated from the booster piston 2.

As shown in FIG. 2, an annular bead 3c is integrally formed on the periphery of the through hole 32, and the annular beads 3b and 3c are connected approximately along a common tangent between the annular bead 3c and the annular bead 3c. At least two straight beads 3d, 3d are raised on one side of the piston diaphragm 3, in the illustrated example, on the rear surface.
These beads 3b, 3c, and 3d cooperate to enhance the tensile rigidity of the piston diaphragm 3.

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 on a flat bearing 9 provided in the extension cylinder 1d, 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 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 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 tube 1d
It is regulated by contacting the inner side of the end wall 1e. 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 tightening a lock nut 26 which is also screwed onto the input rod 11. A ventilation hole 27 is bored in the movable stopper plate 25 so as not to block the air inlet 6.

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.

Next, the connection structure between the tie rod 30 and the booster shell 1 will be explained.

The tie rod 30 is integrally formed with a mounting bolt 33 that penetrates the front wall of the booster shell 1 and projects forward thereof, and the front part of each tie rod 30 is attached to a connecting plate 34 that abuts the inner surface of the front wall of the booster shell 1. The tie rods 30 are fixedly connected to each other.
Then, the mounting bolt 33 is passed through a mounting flange 36 that is integrated with the cylinder body 55 of the brake master cylinder M, which is stacked on the front surface of the booster shell 1,
By screwing and tightening the nut 35 at the tip, the tie rod 30, the connecting plate 34, and the booster shell 1 are connected.
The front wall and the mounting flange 36 are connected together. At that time, an annular seal member 38 is loaded into an annular groove 37 formed on the front surface of the connecting plate 34 so as to surround the bolt 33, and the annular seal member 38 is inserted between the bolt 33, the connecting plate 34, and the inner surface of the front wall of the booster shell 1. in airtight contact. In this way, the annular seal member 3
8, one annular seal member 38 can prevent negative pressure from leaking from two paths: between the inner surface of the front wall of the booster shell 1 and the connecting plate 34, and between the connecting plate 34 and the bolt 33. . Connecting plate 34
also functions as a spring receiving plate that supports the fixed end of the return spring 7, and the elastic force of the return spring 7 can be borne by the tie rod 30, thereby eliminating the burden on the booster shell 1.

Furthermore, the tie rod 30 has a booster shell 1.
Mounting bolt 3 that penetrates the rear wall and projects to the rear
9 and a stepped flange 41 that abuts the inner surface of the rear wall of the booster shell 1 are integrally formed, and the stepped flange 41 is fitted into a support tube 43 that is welded and fixed to the inner surface of the rear wall of the booster shell 1, Its retaining ring 4
By locking the tie rod 2 to the support tube 43, the tie rod 3
0 and the rear wall of the booster shell 1 are integrally connected.
At this time, the annular seal member 45 is loaded into the annular groove 44 between the small diameter portion of the stepped flange 41 and the support tube 43.

In this way, the front and rear bowl-shaped bodies 1F, 1R and the mounting flange 36 are connected together by the tie rod 30 to form the assembly of the booster S and the master cylinder M, so that the outer bead of the piston diaphragm 3 Both bowl-shaped bodies 1 holding 3a
The means for fixing the opposing ends of F and 1R to each other is no longer necessary.

The mounting bolt 39 is inserted into the front wall W of the vehicle compartment, and a nut 40 is screwed onto the tip of the bolt 39 and tightened to attach the tie rod 30 to the front wall W of the vehicle compartment.
sticks to. Therefore, the assembly of the booster S and the master cylinder M is attached to the front wall W of the passenger compartment via the tie rod 30.

Booster piston 2 penetrated by tie rod 30
A sealing means is provided between the booster piston 2 and the tie rod 30 in order to seal the through hole 31 so as not to interfere with the operation of the piston 2. The sealing means is composed of a bellows-shaped telescopic boot 46 made of an elastic material such as rubber.
Covering the outer periphery of the tie rod 30 with the cylindrical portion 46a of No. 6,
The front end 46b is fitted into an annular groove 47 formed on the outer circumferential surface of the tie rod 30, while the rear end 46c is fitted into an annular groove 48 formed on the outer circumferential surface and an annular groove protruding from the inner circumferential surface of the through hole 31. It is fixed to the booster piston 2 by fitting with the projection 49. And elastic boots 4
The rear end 46c of the piston diaphragm 3 and a portion surrounding the through hole 32 on the front surface of the piston diaphragm 3 are brought into close contact with each other so as to be able to be separated, thereby sealing the through hole 32. Therefore, the first working chamber A
Only when the atmospheric pressure in the second working chamber B becomes higher than that in the second working chamber B, a gap is created between the two working chambers 46c and 3 due to the difference in atmospheric pressure.

In the vehicle interior, a brake pedal 52, which is pivoted 51 on a fixed bracket 50, is connected to the rear end of the input rod 11 of the booster S via an adjustment connecting fitting 53. 54 is a return spring that biases the brake pedal 52 rearward.

Cylinder body 55 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 56 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 52, which are connected to each other, are returned to a predetermined retracted position where the movable stopper plate 25 abuts the fixed end wall 1e, and are held by the spring force of the spring 24, and the valve piston 12 is held by the spring force of the spring 24. The front face of the valve part 13c is pressed through the second valve seat ₁₀₂ , and the front face of the valve part 13c is pushed back until it comes into light contact with 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 movable stopper plate 25 described above.

As described above, during engine operation, the first working chamber A, which always stores negative pressure, communicates with the second working chamber B through the through hole 17, the gap g, and the through hole 18, and also through the front through hole of the valve part 13c. Since the second valve seat 102 closes the second valve seat ₁₀₂ , 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 returns to the spring 7.
occupies the illustrated retracted position with a resilient force of .

Now, if the brake pedal 52 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 the second working chamber B becomes higher than that in the first working chamber A. Due to the pressure difference between the two chambers A and B, a forward pressing force is applied to the piston diaphragm 3. In response to this force, the booster piston 2 moves forward against the return spring 7 and moves the output rod 22a forward via the elastic piston 21, thereby driving the operating piston 56 of the brake master cylinder M forward. , the vehicle is braked.

When the actuating piston 56 is driven by the forward movement of the output rod 22a, a forward thrust load acts on the cylinder body 55, but this load is transmitted to the vehicle body, that is, the front wall W of the passenger compartment via the tie rod 30. Supported. Therefore, the above-mentioned load hardly acts 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 52 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 depressing force of the brake pedal 52 is released, the input rod 11 is moved backward due to the reaction force applied to the valve piston 12 and the elastic force of the return spring 24, which causes the second valve seat 10 ₂ to move toward the valve portion 13c. and seat the valve portion 13c in 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, and When the pressure difference disappears, the booster piston 2 moves backward by the elastic force of the return spring 7, and the protrusion 3e 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 1e, 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.

If the brake pedal 52 is depressed and the booster piston 2 is moved forward with no negative pressure stored in the first working chamber A, the air in the first working chamber A will flow sufficiently toward the intake manifold due to pipe resistance, etc. The residual air in the first working chamber A is compressed because the air is not discharged into the first working chamber A. However, if the pressure in the first working chamber A becomes higher than that in the second working chamber B, some of the residual air in the first working chamber A is compressed. enters between the rear surface of the booster piston 2 and the front surface of the piston diaphragm, and the portion of the front surface of the piston diaphragm surrounding the through hole 32 is connected to the telescopic boot 4
6 in a direction away from the rear end 46c, a gap is created between both 3 and 46c, and both working chambers A and B communicate with each other via the gap and the through hole 32 of the piston diaphragm 3. Therefore, the air pressures in both working chambers A and B are quickly balanced through the gap and the through hole, so that problems such as excessive rearward pressing force acting on the piston diaphragm 3 and causing it to bulge rearward are prevented. Prevented in advance.

When the above-mentioned pressure difference disappears, the front surface of the piston diaphragm 3 comes into close contact with the rear end 46c of the telescopic boot 46 again.

As described above, according to the present invention, the rear ends of at least two tie rods 30 that pass through the booster piston 2 and are parallel to each other are fixed to the rear bowl-shaped body 1R, and the front parts of the tie rods 30 are connected to each other. The connecting plate 34 is brought into contact with the inner surface of the front bowl-shaped body 1F, and the front bowl-shaped body 1F and the cylinder body 55 are fixed to the front end of each tie rod 30. Both bowl-shaped bodies 1
Positioning means 1a and 1b are provided between the opposing ends of F and 1R to allow relative movement in the axial direction but restrict relative movement in the circumferential direction. By simply connecting the front part of each tie rod 30, which has been fixed in advance to the shaped body 1R, to the connecting plate 34, it is possible to suppress the wobbling of the front part of the tie rod 30 and keep the distance between the axes of the tie rods 30 constant. Positioning when fixing the front shell 1F to the front end of the tie rod 30 is easy, and the opposing ends of the front and rear bowl-shaped bodies 1F and 1R are aligned in the circumferential direction by the positioning means 1a and 1b. Since they are positioned correctly, the tie rods 30 are correctly set in a parallel relationship without falling down when the assembly is completed, and as a result, the assembly work of the device can be carried out quickly and accurately.

Furthermore, the cylinder body 55 and both bowl-shaped bodies 1F, 1
Since the three members R are connected by the tie rod 30, the tie rod 30 can reliably restrict the relative movement in the axial direction between the opposing ends of the two bowl-shaped bodies 1F and 1R. There is no problem in having a structure in which the positioning means 1a, 1b allow relative movement in the axial direction.

As described above, since the connecting plate 34, which functions as a retainer to keep the distance between the axis of the tie rods 30 constant, also functions as a reinforcing plate to increase the rigidity of the front shell 1F, the positioning means 1a, 1b It is sufficient to have a simple structure that allows relative movement in the axial direction of both bowl-shaped bodies 1F and 1R, and this can greatly contribute to simplifying the structure of the apparatus.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing one embodiment of the assembly of the present invention, and FIG. 2 is a plan view of a piston diaphragm therein. M...Master cylinder, S...Boosting device, 1...
...Booster Ciel, 1F...Front bowl-shaped body, 1R...
... Rear bowl-shaped body, 1a, 1b ... Claw pieces and notches constituting positioning means, 34 ... Connection plate, 2 ... Booster piston, 3 ... Piston diaphragm,
30... Tie rod, 55... Cylinder body, 5
6... Working piston.

Claims (1)

[Claims] 1. The booster shell 1 of the booster S, which houses the booster piston 2 and the piston diaphragm 3 whose inner peripheral end is connected to the booster piston 2, is attached to the front bowl-shaped body 1F and the rear bowl-shaped body 1R. The outer peripheral end of the piston diaphragm 3 is inserted between the opposing ends of both the bowl-shaped bodies 1F and 1R, and the cylinder body 55 of the master cylinder M is arranged on the front surface of the front bowl-shaped body 1F. In the case where the booster piston 2 is connected to the operating piston 56 that slides on the cylinder body 55, the rear ends of at least two tie rods 30 that pass through the booster piston 2 and are parallel to each other are fixed to the rear bowl-shaped body 1R. At the same time, the front parts of the tie rods 30 are connected to each other via a connecting plate 34, and this connecting plate 34
is brought into contact with the inner surface of the front bowl-shaped body 1F, and the front bowl-shaped body 1F and the cylinder body 55 are fixed to the front end of each of the tie rods 30, and further the bowl-shaped bodies 1F and 1R are opposed to each other. An assembly of a booster and a master cylinder, characterized in that positioning means 1a and 1b are provided between the ends to permit relative movement in the axial direction but restrict relative movement in the circumferential direction.