JPS628345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a connecting device between a negative pressure booster and a master cylinder, which is mainly used in the brake system of an automobile, and in particular to a booster shell attached to a vehicle body; a freely housed booster piston; an inner peripheral part is fixed to the rear surface of the booster piston, and an outer peripheral part is fixed to the booster shell, and cooperates with the booster piston to create a negative pressure source inside the booster shell; a piston diaphragm that partitions into a continuous first working chamber at the front and a second working chamber at the rear; an input rod connected to the booster piston so as to be able to move forward and backward; a control valve that selectively communicates with the first working chamber or the atmosphere; passing through the booster piston;
a tie rod connecting the front and rear walls of the booster shell; a sealing means provided between the tie rod and the booster piston to permit operation of the piston; and a negative pressure booster. Regarding the master cylinder connected to the outer surface of the front wall of the booster shell, the tie rod is used to easily and firmly connect the booster and the master cylinder, and the sealing structure at the tie rod penetration part of the booster shell is simple and reliable. The purpose is to

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Booster shell 1 of negative pressure booster S
consists of a pair of front and rear bowl-shaped bodies 1F and 1R molded from a lightweight thin-walled steel plate or synthetic resin, and a plurality of claw pieces 1a protruding from the opening of the rear bowl-shaped body 1R at equal intervals on the circumference. The two bowl-shaped bodies 1F, 1R are mutually positioned by engaging with a plurality of notches 1b formed at equal intervals on the circumference in the opening of the front bowl-shaped body 1R, and the two bowl-shaped bodies 1F, 1R is connected between its front and rear opposing walls via one or more tie rods 30. The connection structure between the booster shell 1 and the tie rod 30 will be described later.

Inside the booster shell 1 are a booster piston 2 accommodated therein so as to be able to reciprocate back and forth, and a piston made of rubber or the like whose inner circumference is fixed to the rear surface and whose outer circumference is sandwiched between the bowl-shaped bodies 1F and 1R. The diaphragm 3 divides the chamber into a first working chamber A at the front and a second working chamber B at the rear. A portion of the piston diaphragm 3 located between the inner circumferential surface of the booster shell 1 and the outer circumferential surface of the booster piston 2 is bent into a U-shaped cross section so as to protrude toward the first working chamber A side. The rolling of the portion 3a allows the booster piston 2 to move forward and backward.

The booster piston 2 and the piston diaphragm 3 have a through hole 31 through which the tie rod 30 passes.
and 32, respectively, and the through hole 32 of the piston diaphragm 3 has a front surface 3c of the piston diaphragm 3 that can be separated from the booster piston 2.
to open. 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 1d of the rear extension cylinder 1c 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 protrusion 3b formed 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 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 1c, 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 1 is provided on the front inner wall of the valve cylinder 8.
0 ₁ , and at the front of the valve cylinder 8 is a valve piston 12 connected to the input rod 11 and forming the front end thereof.
are slid together to form an annular second valve seat 102 surrounded by the first valve seat ₁₀₁ 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 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 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 21 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 backward limit is determined by the movable stopper plate 25 screwed onto the input rod 11 when the rear extension cylinder 1c
It is regulated by coming into contact with the inside of the end wall 1d. 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.

A mounting bolt 33 and a stopper 60 in the form of a circular flange are integrally formed on the front part of the tie rod 30.
The mounting bolt 33 is passed through the retainer 34, and the stopper 60 is fitted into the occluded circular recessed hole 61 of the retainer 34. An annular groove 37 surrounding the tie rod 30 is formed in the contact surface of the retainer 34 with the front wall of the booster shell 1, and within the annular groove 37, the stopper 6
A retaining ring 62 which cooperates with the tie rod 30 to clamp the retainer 34 is secured to the tie rod 30.

The mounting bolt 33 of the tie rod 30 passes through the front wall of the booster shell 1 and the mounting flange 36 of the master cylinder M that comes into contact with the outer surface of the front wall, and a nut 35 is screwed onto the outer end of the bolt 33 to connect the nut 35 and the stopper 60. Retainer 34, mounting flange 3 between
6 is tightened across the front wall of the booster shell 1, thereby integrally connecting the tie rod 30, the retainer 34, the front wall of the booster shell 1, and the mounting flange 36. At this time, an annular seal member 38 is loaded into an annular groove 37 surrounding the bolt 33, and brought into airtight contact with the bolt 33, the retainer 34, and the inner surface of the front wall of the booster shell 1. When the annular seal member 38 is arranged in this way, the one annular seal member 38 prevents negative pressure from leaking in two paths: between the inner surface of the front wall of the booster shell 1 and the retainer 34, and between the retainer 34 and the mounting bolt 33. can do. The retainer 34 supports the fixed end of the return spring 7, and allows the tie rod 30 to bear the elastic force of the return spring 7, thereby eliminating the burden on the booster shell 1.

Furthermore, the tie rod 30 is integrally formed with a mounting bolt 39 that penetrates through the rear wall of the booster shell 1 and projects rearward, and a stepped flange 41 that abuts the inner surface of the rear wall of the booster shell 1. 1. Fit the stepped flange 41 into the support tube 43 welded to the inner surface of the rear wall, and attach the stop ring 42 to the support tube 4.
3, the tie rod 30 and the rear wall of the booster shell 1 are integrally connected. At that time, the annular groove 4 between the small diameter part of the stepped flange 41 and the support tube 43
4 is loaded with the annular seal member 45.

The mounting bolt 39 passes through the front wall W of the vehicle compartment, and a nut 40 is screwed onto the tip of the bolt 39 and tightened to secure the tie rod 30 to the front wall of the vehicle compartment.

Thus, the booster shell 1 is attached to the front wall W of the passenger compartment via the tie rod 30, and the master cylinder M is supported by the booster shell 1 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 peripheral surface of the tie rod 30, while the rear end 46c is fitted into an annular groove 48 formed on the outer peripheral surface of the tie rod 30 and an annular groove 47 formed on the outer peripheral surface of the tie rod 30. It is fixed to the booster piston 2 by fitting with the annular projection 49. Then, the rear end 46c of the telescopic boot 46 and the portion surrounding the through hole 32 of the front surface 3c of the piston diaphragm are brought into close contact with each other so as to be separable, thereby sealing the through hole 32. Therefore, the first
Only when the pressure in the working chamber A becomes higher than that in the second working chamber B, the difference in pressure between the two
A gap is created between c and 3c.

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 urges the brake pedal 52 rearward.

The rear end of the cylinder body 55 of the master cylinder M penetrates the front wall of the booster shell 1 and enters the first working chamber A.
The output rod 2 of the booster S is inserted into the rear end of the operating piston 56 inside the cylinder body 55.
2a to face each other.

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 held in a predetermined retracted position where the movable stopper plate 25 abuts the fixed end wall 1d by the spring force of the return spring 24, and the valve piston 12 is Valve portion 13c via second valve seat ₁₀₂
The front surface of the valve body holding cylinder 14 is pressed and moved back until it lightly contacts the front surface of the valve body holding cylinder 14, thereby forming a small gap g 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, 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 opening of the valve portion 13c. is closed by 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, when 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, moves 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 and blocks communication between the working chambers A and B. At the same time, the second valve seat ₁₀₂ separates from the valve portion 13c and connects the second working chamber B to the through hole 18 and the valve body 13.
It communicates with the atmosphere inlet 6 through the inside. 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 generated between B, the booster piston 2 moves forward against the return spring 7, and the elastic piston 21
Since the output rod 22a is advanced through the
Braking is applied to the vehicle. In this case, due to the pressure difference generated between the working chambers A and B, the front surface 3c of the piston diaphragm 3
c, so that the two working chambers A and B are reliably cut off.

When the actuating piston 56 is driven, a forward thrust load is applied to the cylinder body 55 as described above, but this load is transmitted to and supported by the vehicle body, ie, the front wall W of the vehicle interior, via the tie rod 30. 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 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 ₁₀₂ 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. When the pressure difference disappears, the booster piston 2 moves backward by the elastic force of the return spring 7, and the protrusion 3b 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 1d, 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 3c and presses the portion of the front surface of the piston diaphragm 3c that surrounds the through hole 32 away from the rear end 46c of the telescopic boot 46, so that the space between both 3c and 46c is A gap is created between the piston diaphragm 3 and the working chambers A and B communicate with each other through 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 32, so that an excessive rearward pressing force acts on the piston diaphragm 3, causing it to bulge and deform. is prevented. When the above-mentioned pressure difference disappears, the front surface 3c of the piston diaphragm comes into close contact with the rear end 46c of the telescopic boot 46 again.

As described above, according to the present invention, the mounting flange 36 and the retainer 34 of the master cylinder M penetrated by the tie rod 30 are brought into contact with the outer and inner surfaces of the front wall of the booster shell 1, respectively, and the stopper 6 protruding from the tie rod 30 is attached. and a nut 35 screwed onto the outer end of the tie rod 30.
6 and the retainer 34, and then tighten the retainer 34.
An annular groove 37 surrounding the tie rod 30 is formed on the contact surface with the front wall of the booster shell 1, and an annular seal member 38 is loaded into the annular groove 37, so that the master cylinder M is connected to the booster shell via the tie rod 30. 1, and it is also possible to transmit the forward thrust load received from the master cylinder M side to the vehicle body via the tie rod 30, thereby transferring the load to the booster of the booster S. Since it is possible to avoid the effect on the booster shell 1, there is no need to provide the booster shell 1 with high rigidity to withstand the above load, and by molding it from thin steel plate, synthetic resin, etc., its weight can be reduced. There are advantages that can be achieved. In this case, the front wall of the booster shell 1 is tightened by the mounting flange 36 of the master cylinder M and the retainer 34, so there is no risk of deforming the front wall of the booster shell 1. Also, since the retainer 34 is configured separately from the tie rod 30, the tie rod Compared to the case where the retainer 34 is formed integrally with the retainer 30, both 30 and 34 can be easily processed and material costs can be reduced. Furthermore, by using the retainer 34, two paths of sealing are required between the inner surface of the front wall of the booster shell 1 and the retainer 34 and between the retainer 34 and the tie rod 30. By loading the booster shell 1, the two passages can be reliably sealed, so the sealing structure of the tie rod penetrating portion of the booster shell 1 can be simplified.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of one embodiment of the present invention. A, B...First and second working chambers, M...Master cylinder, S...Negative pressure booster, 1...Booster shell, 2...Booster piston, 3...Piston diaphragm, 5...Control Valve, 11... Input rod, 30... Tie rod, 34... Retainer, 3
5... Nut, 36... Mounting flange, 37...
Annular groove, 38... Annular sealing member, 46... Sealing means, 60... Stopper.

Claims (1)

[Claims] 1 booster shell 1 and that booster shell 1
A booster piston 2 is housed inside the booster shell 1 so as to be able to move back and forth; a piston diaphragm 3 that partitions the interior of the booster shell 1 into a first working chamber A at the front connected to a negative pressure source and a second working chamber B at the rear; an input rod connected to the booster piston 2 so as to be freely retractable 11
a control valve 5 that selectively communicates the second working chamber B with the first working chamber A or the atmosphere in conjunction with the input rod 11; a tie rod 30 connecting the front and rear walls of the booster piston 2; a sealing means 46 provided between the tie rod 30 and the booster piston 2 to allow the piston 2 to operate;
A negative pressure booster S is constructed by connecting a master cylinder M to the outer surface of the front wall of the booster shell 1, and the die rod 30 penetrates the outer and inner surfaces of the front wall of the booster shell 1. The mounting flange 36 and the retainer 34 of the master cylinder M are brought into contact with each other, and the mounting flange 36 and the retainer 34 are tightened by a stopper 60 protruding from the tie rod 30 and a nut 35 screwed onto the outer end of the tie rod 30. and the booster shell 1 of the retainer 34
A connecting device for a negative pressure booster and a master cylinder, comprising an annular groove 37 surrounding the tie rod 30 formed in the contact surface with the front wall, and an annular seal member 38 loaded into the annular groove 37.