JPS6250336B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a booster shell of a negative pressure booster on the front surface of the front wall of the vehicle compartment, and a cylinder body of a master cylinder operated by the booster on the front of the booster shell. The present invention relates to a negative pressure booster and a master cylinder assembly, respectively.

As such an assembly, the present applicant previously proposed a booster shell of a negative pressure booster in front of the front wall of the passenger compartment, and a master cylinder operated by the booster in front of the booster shell. Each cylinder body is arranged, and a pair of upper and lower tie rods extending parallel to the centerline of the booster shell are passed through both the front and rear walls of the booster shell, and the front ends of the tie rods are fixed to the cylinder body. We have proposed a system in which the rear ends of these tie rods are fixed to the front wall of the vehicle compartment, and the tie rods, the cylinder body, and the front wall of the vehicle compartment form a rectangular rigid frame that extends in the longitudinal and vertical directions (patent application). (See No. 56-53419).

With the above configuration, the reinforcing action of both tie rods allows the booster shell to be molded from a lightweight material, such as a thin steel plate or synthetic resin, which reduces the weight of the entire assembly and reduces vibrations in the vertical and horizontal directions of the master cylinder. It has the advantage of being able to suppress

The present invention aims to further reduce the weight of the above assembly.
It is an object of the present invention to provide the negative pressure type booster and master cylinder assembly in which the weight of both tie rods is reduced without impairing the strength of the rigid frame.

Hereinafter, an embodiment in which the present invention is applied to a brake master cylinder will be described with reference to the drawings.

The booster shell 1 of the 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;
A plurality of claw pieces 1a protruding from the opening of R at equal intervals on the circumference are engaged with a plurality of notches 1b formed at an opening of the front bowl-shaped body 1F at equal intervals on the circumference. The two bowl-shaped bodies 1F, 1R are positioned relative to each other, and the two bowl-shaped bodies 1F, 1R are connected via a pair of tie rods 30 between their front and rear opposing walls. The connection structure between the booster shell 1 and the tie rod 30 will be described later.

A booster piston 2 is housed inside the booster shell 1 so as to be able to reciprocate back and forth, and an annular groove 61 is formed in the rear surface of the booster piston 2.

Annular beads 3a and 3b are formed on the outer and inner periphery of the piston diaphragm 3, respectively, and the annular bead 3a on the outer periphery has two positioning holes protruding from its end surface at equal intervals on the circumference. Protrusion 3
c into each positioning hole 1c formed on the outer periphery of the rear bowl-shaped body 1R, and both bowl-shaped bodies 1F, 1R are assembled.
It is clamped by. The annular bead 3b on the inner circumference is fitted into the annular groove 61 of the booster piston 3, and the piston diaphragm 3 and the booster piston 2 allow the inside of the booster shell 1 to
It is divided into a working chamber A and a second working chamber B at the rear.

The pressure receiving portion 3d of the piston diaphragm 3 is in close contact with the rear surface of the booster piston 2 and protrudes toward the first working chamber A between the outer circumferential surface of the booster piston 2 and the inner circumferential surface of the front bowl-shaped body 1F. U
The U-shaped bent portion allows the booster piston 2 to move forward and backward by rolling.

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 connected to a control valve 5, which will be described later.
The air inlet port 6 is alternately connected to the first working chamber A or to the air inlet 6 which opens in the end wall 1e of the rear extension tube 1d of the booster shell 1 through the opening.

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 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 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.
An annular second valve seat 102 surrounded by the first valve seat ₁₀₁ 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 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 slidably fitted into the small diameter hole 20 in order.
A reaction piston 23 having a smaller diameter than the valve piston 21 is slidably fitted therein, and a small shaft 12a protruding from the front end surface of the valve piston 21 is inserted into the small diameter hole 20 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 coming into contact with the inside 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 that the air inlet 6 is not blocked by the stopper plate 25.

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 that penetrates the front wall of the booster shell 1 and projects forward thereof is integrally formed on the tie rod 30, and a spring receiving plate 34 that comes into contact with the inner surface of the front wall of the booster shell 1 is fixed. Then, the mounting bolt 33 is passed through the mounting flange 36 of the brake master cylinder M stacked on the front surface of the booster shell 1, and the nut 35 is screwed onto the tip of the bolt 33 and tightened. and the mounting flange 36 are connected together. At that time, an annular groove 37 formed on the front surface of the spring receiving plate 34 so as to surround the bolt 33
An annular seal member 38 is fitted to seal the tie rod through hole in the front wall of the booster shell 1. The spring support plate 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 removing the load on the booster shell 1.

Further, the tie rod 30 is integrally formed with a mounting bolt 39 that penetrates the rear wall of the booster shell 1 and projects rearward thereof, and a stepped flange 41 that abuts the inner surface of the rear wall of the booster shell 1. The stepped flange 41 is fitted into the support tube 43 that is welded and fixed to the inner surface of the rear wall, and its retaining ring 42 is locked to the support tube 43, thereby integrating the tie rod 30 and the rear wall of the booster shell 1. Connect to. At that time, the small diameter part of the stepped flange 41 and the support tube 4
An annular seal member 45 for sealing the tie rod through hole in the rear wall of the booster shell 1 is fitted into the annular groove 44 between the booster shells 1 and 3.

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.

Thus, the booster shell 1 is attached to the front wall W of the passenger compartment via the tie rod 30, and the brake master cylinder M is connected to the booster shell 1 via the tie rod 30.

A pair of tie rods 30 are arranged so as to sandwich the center line of the booster shell 1, that is, the axis of the input rod 11, and extend parallel to the center line at predetermined intervals vertically and horizontally. A rigid frame in the form of a rectangle extending in the front-rear and diagonal up-down directions has the tie rods 30, 30 as one opposing side and the front wall W of the vehicle interior and the mounting flange 36 of the brake master cylinder M as the other opposing side. configured. As shown in FIG. 4, the space between the rear wall of the annular groove 47 located at the front and the stepped flange 41 located at the rear of each tie rod 30, 30 is formed flat so that the cross section is approximately elliptical. As shown in FIG. 2, both tie rods 30, 30 are arranged such that the wide side faces f of their flat portions 30a face each other. In this way, each tie rod 3
By forming the flat portion 30a on a portion of the tie rods 30, 30, the weight of each tie rod 30, 30 can be reduced compared to a case where all of the tie rods have a circular cross section. Note that each tie rod 30, 30 may be formed entirely flat, or the cross-sectional shape of the flat portion 30a may be rectangular.

A pair of dedicated bolts 66 for attachment to the front wall W of the passenger compartment are welded to the rear wall of the booster shell 1, facing each of the tie rods 30, 30, with a predetermined interval in the vertical and horizontal directions, with the center line in between. Fixed. In the illustrated example, the distance a between the shafts of both tie rods 30, 30 in the vertical direction is set to be longer than the distance b between the shafts in the left and right direction.

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 constituted by a bellows-shaped retractable boot 46 made of an elastic material such as rubber, and is provided in the first working chamber A.
The boot 46 surrounds the tie rod 30, and the front end 46a is inserted into the annular groove 47 of the tie rod 30.
Then, the rear ends 46b are fitted into the through holes 31, respectively.

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 a 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, the operation of this embodiment will be explained.

When the brake master cylinder M vibrates while the vehicle is running, the rigid frame including both tie rods 30, 30 resists the vibration in the direction parallel to the line segment connecting the axes of both tie rods 30, 30. Even if the short diameter sides of the flat portions 30a of both tie rods 30, 30 are located in this direction, the strength of the rigid frame is not impaired in any way. Furthermore, vibrations in a direction perpendicular to the line segment can be dealt with with sufficient strength because the longer diameter sides of the flat portions 30a of both tie rods 30, 30 are located in that direction. As a result, vibrations of the brake master cylinder M in the vertical and horizontal directions are suppressed, which prevents air bubbles from forming in the hydraulic fluid in the reservoir, which can cause a paper lock phenomenon, and prevents hydraulic fluid from leaking from the reservoir cap vent. The braking action is performed reliably. Additionally, while a vehicle is running, it generally vibrates more strongly in the vertical direction than in the horizontal direction.
Due to the relationship between the center distances a>b of the tie rods 30, 30, it is possible to rationally deal with vibrations in the vertical and horizontal directions.

Next, to explain the operation of the booster S, the state shown in FIG. The spring 24 returns to the predetermined retreat position where it abuts the wall 1e.
and the valve piston 12 is held by a spring force of
presses the front surface of the valve portion 13c via the second valve seat ₁₀₂ and moves it backward until it lightly contacts the front surface of the valve body holding cylinder 14, thereby pressing the front surface of the valve portion 13c through the second valve seat 102.
A slight gap g is formed between the valve portion ₁ and the valve portion 13c. In such a state, the above-mentioned movable stopper plate 2
It can be easily obtained by adjusting 5.

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, 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 ₁₀₁ and the valve part 13c is extremely narrow as described above, the valve part 13c immediately seats on the first valve part 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 actuating piston 56 of the brake master cylinder M is driven forward, and the vehicle is braked.

When the actuating piston 56 is driven, a forward thrust load is applied to the cylinder body 55, and this load is transmitted to the vehicle body, that is, the front wall W of the vehicle interior, through the tie rod 30 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 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 second 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 large gap. When the pressure difference between them disappears, the booster piston 2 moves back due to the elastic force of the return spring 7, and the protrusion 3 of the piston diaphragm 3
e 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.

As described above, according to the present invention, the booster shell of the negative pressure booster is mounted in front of the front wall of the vehicle compartment, and the cylinder body of the master cylinder operated by the booster is mounted in front of the booster shell. A pair of upper and lower tie rods extending parallel to and sandwiching the center line of the booster shell are passed through both the front and rear walls of the booster shell, and the front ends of the tie rods are fixed to the cylinder body. In a case where the rear end is fixed to the front wall of the vehicle compartment and the tie rods, cylinder body and front wall of the vehicle compartment form a rectangular rigid frame extending in the longitudinal and vertical directions, a part or all of each tie rod may be Since it is formed to have a flat cross section and both tie rods are arranged so that the wide sides of their flat parts face each other, the strength of the rigid frame containing them will not be impaired in any way due to the specific arrangement relationship of both tie rods. Therefore, the weight of both tie rods can be reduced, and the weight of the entire assembly can be reduced.

[Brief explanation of the drawing]

The drawings show one embodiment of the assembly of the present invention.
Figure 1 is a side view, Figure 2 is a back view, and Figure 3 is a side view.
FIG. 4 is a sectional view taken along the line shown in FIG. 3. M...Brake master cylinder as a master cylinder, S...Negative pressure booster, f...Side surface,
W...Front wall of vehicle compartment, 1...Booster shell, 30
...Tie rod, 30a...Flat part, 55...Cylinder body.

Claims (1)

[Claims] 1. A booster shell of a negative pressure booster is installed in front of the front wall of the passenger compartment, and in front of the booster shell,
The cylinder bodies of the master cylinders operated by the booster are respectively disposed, and a pair of upper and lower tie rods extending parallel to and sandwiching the center line of the booster shell are passed through both the front and rear walls of the booster shell, The front ends of the tie rods are fixed to the cylinder body, and the rear ends of the tie rods are fixed to the front wall of the vehicle compartment, so that the tie rods, the cylinder body, and the front wall of the vehicle compartment are connected front and rear, up and down. A rectangular rigid frame extending in the direction, in which part or all of each tie rod is formed to have a flat cross section, and both tie rods are arranged so that the wide sides of the flat parts face each other. , negative pressure booster and master cylinder assembly.