JPH06171494A - Connecting method of reinforced plate and connecting bolt to booster shell - Google Patents

Abstract

PURPOSE:To improve the connecting strength among a booster shell, a reinforced plate and a connecting bolt and secure airtightness in this booster shell by forming a flange pressing an end wall of this booster shell to its inward, while making up both first and second deformed parts on the aforesaid end wall. CONSTITUTION:A large diametral base 36a piercing through respective through holes 26, 25 of an end wall of a booster shell and a reinforced plate 30 is formed in a shank 36 of a connecting bolt 30. On the other hand, a disklike recess 37 is formed on an opposed surface with the aforesaid end wall of the reinforced plate 30 as surrounding the large diametral base 36a and a cylindrical void 38 is formed in space between an internal circumferential surface of the through hole 25 and an outer circumferential surface of the large diametral base 36a respectively. In addition, a flange 39 for caulking the large diametral base 36a in the axial direction and pressing the end wall to the booster shell inwards is installed in this large diametral base 36a. Furthermore, both first and second deformed parts to be confined in the disklike recess 37 and the cylindrical void 38 are formed on the end wall which is bent in two stages between the reinforced plate 30 and a connecting bolt 33, so that the connecting strength is well heightened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting a reinforcing plate and a connecting bolt to a booster shell in a negative pressure booster for boosting a brake master cylinder of an automobile with negative pressure, and more particularly to an end wall of the booster shell. On the inner surface of the reinforcing plate that is overlaid on the inner surface, the head of the connecting bolt, through which the shaft portion passes through the through holes of the end wall and the reinforcing plate, is overlapped, and the shaft portion of the connecting bolt is caulked to reinforce the reinforcing plate and the connecting bolt. To improve the method of connecting the end wall to the end wall.

[0002]

2. Description of the Related Art A method for connecting a reinforcing plate and a connecting bolt to such a booster shell is disclosed in, for example, Japanese Patent Laid-Open No. 57-14091.
It is already known as disclosed in Japanese Patent No. 0.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The method of connecting a reinforcing plate and a connecting bolt to a booster shell disclosed in the above publication is such that the shaft portion of the connecting bolt is connected to the lower surface of the head of the booster shell and the end wall of the booster shell and the reinforcing member are connected. While forming a large-diameter base portion that penetrates each through hole of the plate, a conical recess is formed on the surface of the reinforcing plate that faces the end wall, and the large-diameter base portion is caulked in the axial direction so that the end wall is inside the booster shell. By forming a flange that presses inwardly, a deformed portion that is confined in the conical recess is formed in the end wall. According to this method, the booster that is closed in the conical recess of the reinforcing plate is used. Since the deformed portion of the shell also has a conical shape, the coupling strength between the booster shell and the connecting bolt cannot be said to be sufficient in the radial direction or the axial direction. Moreover, the airtightness between the booster shell and the connecting bolt is maintained by the only conical crimping surface between the flange and the booster shell. Pressure leaks to the outside and reliability is low.

The present invention has been made in view of the above circumstances, and has high joint strength between the booster shell, the reinforcing plate and the connecting bolt, and at least the pressure-bonding surface for airtightness between the shell and the connecting bolt. It is an object of the present invention to provide the above-described joining method that can improve reliability of airtightness in two places.

[0005]

In order to achieve the above object, the present invention has a shaft portion of a connecting bolt, which is connected to the lower surface of the head of the connecting bolt, and which penetrates through the through hole of the end wall of the booster shell and the reinforcing plate. While forming a large-diameter base portion, a disc-shaped recess that surrounds the large-diameter base portion and extends in the radial direction is formed on the surface of the reinforcing plate that faces the end wall, and the through hole of the reinforcing plate is formed through the through hole of the reinforcing plate. It is formed to have a larger diameter than the hole, and a cylindrical gap is provided between the inner peripheral surface of the through hole of the reinforcing plate and the outer peripheral surface of the large-diameter base, and the large-diameter base is caulked in the axial direction to form the end wall. It is characterized in that a flange for pushing inward of the booster shell is formed on the large-diameter base portion, and at the same time, first and second deformed portions that are respectively confined in the disc-shaped recess and the cylindrical void are formed in the end wall.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a tandem type negative pressure booster B
1. The booster shell 1 of FIG.
The partition plate 1c is sandwiched between the shell halves 1a and 1b to partition the chamber between the front shell chamber 2 and the rear shell chamber 3 into a partition plate 1c.

A reinforcing plate 30 is joined to the inner surface of the end wall of the front shell half body 1a, and together with the reinforcing plate 30, the front shell half body 1a has a connecting flange of a brake master cylinder M arranged in front thereof. 32 is a pair of connecting bolts 33, 3
3 and nuts 34, 34 screwed to them and fixed.

Further, the rear shell half body 1b is fixed to the dashboard D of the vehicle body by four connecting bolts 47, 47 arranged at each vertex of a quadrangle, and nuts 48, 48 screwed to them. .

The front shell chamber 2 has a front booster piston 4 housed therein so as to be reciprocally movable back and forth, and is superposed on the rear surface of the front booster piston 4 and sandwiched between the front shell half 1a and the partition plate 1c. The attached front diaphragm 5 divides the front negative pressure chamber 2a on the front side into the front working chamber 2b on the rear side.
Further, the rear shell chamber 3 is formed with a rear booster piston 6 housed therein so as to be capable of reciprocating back and forth, and a rear diaphragm which is superposed on the rear surface of the rear booster piston 6 and is sandwiched between the shell half bodies 1a and 1b together with the partition plate 1c. 7 divides the front side negative pressure chamber 3a and the rear side rear working chamber 3b.

The front and rear booster pistons 4 and 6 are each formed into an annular shape by a steel plate, and these are integrally connected to each other via a piston boss 10 made of synthetic resin. The piston boss 10 is slidably supported by the partition plate 1c via the bush 8 and the seal member 9.

A valve cylinder 11 is provided at the rear end of the piston boss 10.
And the bush 1 is attached to a rear extension cylinder 12 protruding from the rear end of the booster shell 1.
3 and the seal member 14 are slidably supported.

The front negative pressure chamber 2a is connected to a negative pressure source (not shown) (for example, inside the intake manifold of the internal combustion engine) via a negative pressure introducing pipe 15, and the first negative pressure chamber of the piston boss 10 is connected.
It communicates with the rear negative pressure chamber 3a through the port 16. Also,
Both the front and rear working chambers 2b and 3b communicate with each other through the second port 17 of the piston boss 10 and the valve cylinder 11
A control valve 18 provided in the front and rear negative pressure chambers 2a, 3
a and an atmosphere introducing port 19 that opens to the end wall of the rear extension cylinder 12 are alternately connected and switched. The control valve 18 is a known valve operated by a brake pedal 21 via an input rod 20.

An output rod 23 is attached to the piston boss 10 and projects forward and is connected to the rear end of the piston 22 of the master cylinder M. The piston boss 10 is attached to the front negative pressure chamber 2a in the backward direction. The biasing return spring 24 is contracted. The fixed end of the return spring 24 is supported by the reinforcing plate 30.

When the input rod 20 is moved forward by depressing the brake pedal 21, the working chambers 2b and 3b are
Since the control valve 18 cuts off the communication with the negative pressure chambers 2a and 3a and communicates with the atmosphere introducing port 19, the working chambers 2b,
Atmospheric pressure acts on 3b, negative pressure chambers 2a, 3a and working chamber 2
The booster pistons 4 and 6 move forward due to a large atmospheric pressure difference between the booster pistons 4 and 6, and the piston 22 of the master cylinder M can be boosted via the output rod 23. Further, when the brake pedal 21 is released and the input rod 20 is retracted, the working chambers 2b and 3b are disconnected from the atmosphere introduction port 19 by the control valve 18 and the negative pressure chamber 2a and
3a, the working chambers 2b, 3b and the negative pressure chamber 2
The pressure difference between a and 3a is reduced, and the booster pistons 4 and 6 are retracted by the force of the return spring 24.

Now, the reinforcing plate 30 for the front shell half 1a
A method of connecting the connecting bolt 33 will be described with reference to FIGS.

In FIG. 3, the connecting bolt 33 is the head 3
5 and a shaft portion 36 projecting from the lower surface thereof, the shaft portion 36 is formed with a large-diameter base portion 36a continuous with the lower surface of the head portion 35. The connecting bolt 36 makes the lower surface of the head 35 contact the inner surface of the reinforcing plate 30, and
The large-diameter base portion 36a is passed through the reinforcing plate 30 and the through holes 25 and 26 of the front shell half body 1a.

A disc-shaped recess 37 is formed on the surface of the reinforcing plate 30 facing the front shell half 1a so as to surround the shaft 36 and spread in the radial direction. The inner peripheral surface of the recess 37 is tapered. Attach.

The through hole 2b of the front shell half 1a is formed so as to fit on the outer periphery of the large diameter base portion 36a, and the through hole 25 of the reinforcing plate 30 is the through hole 26 of the front shell half 1a. Larger diameter than the inner diameter of the through hole 25 and the large diameter base portion 36.
A cylindrical void 38 is formed between the outer peripheral surface of a and a. Then, as shown in FIG. 2, by applying an axial caulking force F from the front of the front shell half body 1a to the large-diameter base portion 36a, the front wall of the front shell half body 1a is pressed inward. Forming the flange 39 for
And a disk-shaped first deformable portion 40 and a cylindrical second deformable portion 41 which are respectively confined in the cylindrical void 38.

Thus, the first shell half 1a is formed with the disk-shaped first deforming portion 40 and the cylindrical second deforming portion 41 by one caulking step, and as a result, the reinforcing plate 30 and the connecting bolt are formed. It will be bent in two steps between 33,
These bent portions can effectively increase the joint strength between the front shell half 1a, the reinforcing plate 30, and the connecting bolt 33.

The airtightness between the front shell half 1a and the connecting bolt 33 is determined by the radial crimping surface between the flange 39 and the first deformable portion 40, the large-diameter base portion 36a and the second deformable portion 4.
Since it is held by the circumferential pressure-bonding surface between the two, even if one of the pressure-bonding surfaces has a poor air-tightness, the air-tightness between the front shell half body 1a and the connecting bolt 33 is ensured and the reliability is improved. It is high, and the leakage of negative pressure from the front shell half body 1a can be reliably prevented.

The method of connecting the reinforcing plate 30 and the connecting bolt 33 to the front shell half body 1a can also be applied to the rear shell half body 1b.

[0023]

As described above, according to the present invention, the shaft portion of the connecting bolt is provided with the large-diameter base portion which is continuous with the lower surface of the head portion and penetrates through the through hole of the end wall of the booster shell and the reinforcing plate. On the other hand, a disk-shaped recess is formed on the surface of the reinforcing plate facing the end wall so as to surround the large-diameter base portion and spread in the radial direction, and the through hole of the reinforcing plate has a larger diameter than the through hole of the end wall. By forming a cylindrical gap between the inner peripheral surface of the through hole of the reinforcing plate and the outer peripheral surface of the large-diameter base, and crimping the large-diameter base in the axial direction, the end wall is pressed inward of the booster shell. Since the first and second deformable portions that are respectively confined in the disk-shaped recess and the cylindrical void are formed in the end wall at the same time that the flange for forming the large-diameter base is formed in the end wall of the booster shell, Second
Due to the formation of the deformed portion, a two-step bent portion is provided between the reinforcing plate and the connecting bolt, and a great bonding strength can be obtained between the booster shell, the reinforcing plate and the connecting bolt. Moreover, the airtightness between the booster shell and the connecting bolt is maintained by the radial crimping surface between the flange and the first deforming portion and the circumferential crimping surface between the large diameter base portion and the second deforming portion. Even if the airtightness of one of the pressure-bonded surfaces should not occur, the airtightness of the booster shell is not hindered, the reliability is high, and leakage of negative pressure from the booster shell can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a negative pressure booster.

FIG. 2 is an enlarged view of part 2 of FIG. 1, showing a reinforcing part and a connecting part of a connecting bolt to a booster shell according to the method of the present invention.

FIG. 3 is a state diagram of a booster shell, a reinforcing plate, and a connecting bolt before being joined.

[Explanation of symbols]

 B Negative pressure booster 1 Booster shell 25 Reinforcing plate through hole 26 Booster shell through hole 30 Reinforcing plate 33 Connecting bolt 35 Head 36 Shaft 36a Large diameter base 37 Disc-shaped recess 38 Cylindrical void 39 Flange 40 First deformation Part 41 Second deformation part

Claims (1)

[Claims] 1. A shaft portion (36) having through holes (26, 25) of the end wall and the reinforcing plate (30) on the inner surface of the reinforcing plate (30) which is superposed on the inner surface of the end wall of the booster shell (1). The head portion (35) of the connecting bolt (33) which penetrates is overlapped, and the shaft portion (36) of the connecting bolt (33) is caulked to attach the reinforcing plate (30) and the connecting bolt (33) to the end wall. In the method of connecting the reinforcing plate and the connecting bolt to the booster shell, the head portion (3) is attached to the shaft portion (36) of the connecting bolt (33).
5) a large diameter base portion (36a) which is connected to the lower surface of the booster shell (1) and penetrates each through hole (26, 25) of the reinforcing plate (30) is formed, while the reinforcing plate (30) is A disk-shaped recess (37) is formed on the surface facing the end wall, the disk-shaped recess (37) surrounding the large-diameter base portion (36a) and extending in the radial direction.
The through hole (25) of 0) is formed to have a larger diameter than the through hole (26) of the end wall, and the inner peripheral surface of the through hole (25) and the outer peripheral surface of the large diameter base portion (36a) of the reinforcing plate (30). Cylindrical void between and (38)
And a large diameter base portion (36a) is caulked in the axial direction to form a flange (39) on the large diameter base portion (36a) for pressing the end wall inwardly of the booster shell (1). Plate-shaped recess (37) and cylindrical void (38)
The first and second deformable portions (40,
41) is formed on the end wall, wherein the reinforcing plate and the connecting bolt are connected to the booster shell.