JPH0611278Y2 - Connection structure of booster piston and valve cylinder in negative pressure booster - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention (1) Field of Industrial Application The present invention relates to a connecting structure of a booster piston and a valve cylinder in a negative pressure booster that boosts a brake master cylinder of an automobile by negative pressure, and in particular, an inner circumference of the booster piston. The elastic bead portion integrally provided in the valve portion is airtightly fitted to the outer periphery of the valve cylinder, and the flange continuously provided to the base portion of the valve cylinder is the booster piston, and a set plate locked to the booster piston. It is related to the improvement that is sandwiched by.

(2) Conventional Technology Such a connecting structure is already known as disclosed in, for example, Japanese Utility Model Laid-Open No. 63-108857, and in the one disclosed in that publication, the flat plate portion of the booster piston is A locking claw is formed by cutting and raising it forward, and the locking plate is pressed against the flange of the valve cylinder to engage with the locking claw.

(3) Problems to be Solved by the Invention However, it is not preferable to cut and raise a part of the flat plate portion of the booster piston for forming the locking claws as in the conventional case because the rigidity of the flat plate portion is reduced to some extent. If the plate thickness of the booster piston is increased to compensate for the decrease in rigidity, the weight will be increased. Further, at the time of connection, it is not easy to press and rotate the set plate against the flange of the valve cylinder.

The present invention has been made in view of such circumstances, and a booster piston and a valve in a negative pressure booster having a simple structure in which the set plate can be easily locked to the booster piston without reducing the rigidity of the booster piston. It is an object to provide a connecting structure of cylinders.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention forms a bottomed cylindrical portion for accommodating a flange of a valve cylinder in a booster piston,
The flange is brought into contact with the bottom wall of the cylindrical portion, a plurality of locking holes are provided at equal intervals in the peripheral wall of the cylindrical portion, and a plurality of notches corresponding to the locking holes are formed on the outer peripheral surface of the flange. Formed at intervals, the set plate enters between the notch and the cylindrical portion when pressed against the flange, and elastically engages with the locking hole and with respect to the notch. It is characterized in that a plurality of locking claws that are engaged in the circumferential direction of the flange are provided in series.

(2) Action According to the above configuration, the rigidity of the booster piston is suppressed as much as possible by forming the locking hole in the peripheral wall of the bottomed cylindrical portion having high rigidity formed in the booster piston.

Further, when connecting the booster piston and the valve cylinder, the flange of the valve cylinder is housed in the bottomed cylindrical portion so that the notch and the locking hole are aligned, and then the set plate is simply pressed against the flange. The engaging claw of the set plate can be immediately engaged with the engaging hole. After the setting, the bottom wall of the bottomed cylindrical portion comes into contact with the flange with a relatively large contact area, and the flange is stably sandwiched between the flange and the set plate. Furthermore, since the relative rotation between the valve cylinder and the booster piston can be reliably regulated by the engagement between the locking claw and the notch, the elastic bead portion on the inner circumference of the booster piston due to the relative rotation can be twisted. Prevent from happening.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, referring to FIG. 1, a booster shell 1 of a negative pressure booster B includes a pair of front and rear shell halves 1 whose opposite ends are connected to each other.
a master cylinder M for braking is attached to the front surface of the front shell half body 1a, and the rear shell half body 1b is fixed to a vehicle body (not shown).

The interior of the booster shell 1 is divided into a negative pressure chamber 4 on the front side and a working chamber 5 on the rear side by a booster piston 2 accommodated in the booster shell 1 so as to be capable of reciprocating back and forth and a diaphragm 3 superposed and bonded on the rear surface. To be done. An outer peripheral bead 3a of the diaphragm 3 is sandwiched between the shell halves 1a and 1b.

The booster piston 2 is made of steel plate and has a center hole 6,
The valve cylinder 7 penetrating the center hole 6 and the booster piston 2 are connected to each other by the following structure.

The valve cylinder 7 is made of synthetic resin, has a tapered portion 7a having a large diameter toward the front, and has a flange 7b integrally connected to the front end of the tapered portion 7a.

On the other hand, the booster piston 2 is provided with a relatively shallow bottomed cylindrical portion 2a whose front side is open, and the center hole 6 is bored in the bottom wall thereof. A peripheral portion of the center hole 6 is formed in an annular hook portion 8 that locks the inner peripheral bead 3b of the diaphragm 3. Then, when the valve cylinder 7 is inserted into the central hole 6 from the front, the tapered portion 7a is fitted into the central hole 6 with the inner peripheral bead 3b interposed therebetween, and the flange 7b is housed in the bottomed cylindrical portion 2a. The rear surface of 7b is brought into contact with and supported by the front surface of the bottom wall of the cylindrical portion 2a. Thus, the inner peripheral bead 3b is integrally provided on the inner peripheral portion of the booster piston 2 and constitutes the elastic bead portion of the present invention which is airtightly fitted to the outer periphery of the valve cylinder 7.

As shown in FIG. 2 and FIG. 3, a plurality of (two in the illustrated example) notches 9 and 9 are provided at equal intervals in the circumferential direction on the outer peripheral surface of the flange 7b. Cylindrical part 2
A plurality of (two in the illustrated example) locking holes 1 penetrating the peripheral wall of a.
0 and 10 are drilled.

Further, the flange 7 is provided at the front opening of the bottomed cylindrical portion 2a.
A set plate 11 for pressing the front surface of b is arranged.
The set plate 11 is made of a steel plate, and a plurality of (two in the illustrated example) locking claws 12, 12 are formed at equal intervals on the outer peripheral edge of the set plate 11 at the notch 9 of the flange 7b. It is adapted to be elastically engaged with the locking hole 10 of 2a.

That is, each locking claw 12 is, as shown in FIG. 2 and FIG.
The arm portion 13 has an elasticity that expands outward in the radial direction, and a mountain-shaped claw portion 14 that is continuously provided at the tip of the arm portion 13 and projects outward in the radial direction. Is on the vertical surface 14a that stands up from the arm 13, and the rear surface is the slope 1
4b, each locking claw 12 is also engaged with the notch 9 in the state of being engaged with the locking hole 10 as is apparent from FIG. 3, so that the relative engagement between the booster piston 2 and the flange 7b. Rotation can be restricted.

With the above structure, the booster piston 2 and the valve cylinder 7 are connected to each other.

A return spring 16 for urging the booster piston 2 and the valve cylinder 7 in the backward direction is contracted between the set plate 11 and the retainer 15 installed on the inner surface of the front wall of the front shell half 1a.

The valve cylinder 7 is provided on the rear shell half 1b so as to project therefrom.
The bush 18 and the seal member 1 on the rear extension cylinder 17 that covers the
It is slidably supported via 9.

The negative pressure chamber 4 is connected to a negative pressure source (not shown) (for example, inside an intake manifold of an internal combustion engine) via a negative pressure introducing pipe 20 and communicates with the inside of the valve cylinder 7 via a first port 21. The working chamber 5 is connected to the valve cylinder 7 via the second port 22.
Communicate with the inside. A control valve 23 is provided in the valve cylinder 7, whereby the second port 22 becomes the first port 21,
The communication is alternately switched to the atmosphere introduction port 24 that opens to the end wall of the rear extension cylinder 17. Control valve 23
Is a known one which is operated by a brake pedal 26 via an input rod 25.

Further, the valve cylinder 7 is equipped with an output rod 28 which projects forward and is connected to the piston 27 of the master cylinder M.

Then, by pressing the brake pedal 26, the input rod 2
5 is moved forward, the second port 22 connected to the working chamber 5
Is the first port 2 connected to the negative pressure chamber 4 by the control valve 23.
Since it is disconnected from 1 and communicated with the air inlet 24, the atmospheric pressure acts on the working chamber 5, and the booster piston 2 is moved by the large pressure difference between the negative pressure chamber 4 and the working chamber 5. The master cylinder M is moved forward and operated via the output rod 28.
The piston 27 can be double-powered. Further, when the brake pedal 26 is released and the input rod 25 is retracted, the first port 21 is controlled by the control valve 23 so that the atmosphere introduction port 2 is opened.
4 and the communication with the first port 21, the pressure difference between the chambers 4 and 5 decreases, and the return spring 16
The booster piston 2 is retracted by the force of.

The output rod 28 integrally includes a large-diameter piston 30 that fits in a cylinder hole 29 that opens at the front end surface of the valve cylinder 7. The large-diameter piston 30 cooperates with an elastic piston 31 and a small-diameter piston 32. A known reaction force mechanism 33 that feeds back the operating reaction force of the output rod 28 to the input rod 25 is configured. In order to prevent the large-diameter piston 30 from coming off the cylinder hole 29, the inner peripheral edge 11a of the set plate 11 is exposed to the opening of the cylinder hole 29.

Next, the operation of this embodiment will be described. In connecting the booster piston 2 and the valve cylinder 7, first, the inner peripheral bead 3b of the diaphragm 3 is attached to the hook portion 8 of the booster piston 2 in the center hole 6 of the valve cylinder 7. While fitting the tapered portion 7a, the rear surface of the flange 7b is brought into close contact with the bottom wall of the bottomed cylindrical portion 2a of the booster piston 2. Then, the inner peripheral bead 3b of the diaphragm 3 is brought into close contact with the tapered portion 7a to maintain airtightness between the inner peripheral bead 3b and the tapered portion 7a, and is firmly locked to the hook portion 8. At this time, the positions of the notch 9 of the flange 7b and the locking hole 10 of the bottomed cylindrical portion 2a are aligned with each other.

Next, after the small-diameter piston 32, the elastic piston 31, and the large-diameter piston 30 are assembled in the cylinder hole 29 of the valve cylinder 7, the set plate 11 is attached to the flange 7b while inserting the locking claw 12 into the notch 9 of the flange 7b. When pressed against the front surface, the locking claw 12 is initially bent inward in the radial direction by the slanted surface 14b of the claw portion 14 sliding on the opening edge of the bottomed cylindrical portion 2a, and the set plate 11 contacts the front surface of the flange 7b. When they come into contact with each other, the claw portion 14 reaches the position of the locking hole 10, and the claw portion 14 engages with the locking hole 10 due to the expansion elasticity of the arm 13. Since the vertical surface 14a of the claw portion 14 is brought into contact with the front end wall of the locking hole 10, it cannot be separated from the locking hole 10.

In this way, the locking claw 12 can be engaged with the locking hole 10 simply by pressing the set plate 11 against the flange 7a, and as a result, the set plate 11 and the bottomed cylindrical portion 2a of the booster piston 2 can be engaged. The booster piston 2 and the valve cylinder 7 can be connected by sandwiching the flange 7a in cooperation with the bottom wall of the.

Moreover, since the bottomed cylindrical portion 2a of the booster piston 2 has an extremely high rigidity, even if the locking hole 10 is bored therein, the rigidity of the booster piston 2 is hardly reduced.

FIG. 5 shows a modification of the locking hole 10, in which the locking hole 10 is bottomed. According to this modification, the rigidity of the bottomed cylindrical portion 2a of the booster piston 2 can be further prevented from decreasing. In the figure, the same reference numerals are given to the portions corresponding to those in the previous embodiment.

C. As described above, according to the present invention, the booster piston is formed with the bottomed cylindrical portion for accommodating the flange of the valve cylinder, and the flange is brought into contact with the bottom wall of the cylindrical portion. A plurality of locking holes are provided at equal intervals on the peripheral wall, and a plurality of notches corresponding to the locking holes are formed at equal intervals on the outer peripheral surface of the flange, and the set plate is pressed against the flange. Since a plurality of locking claws that are inserted between the notch and the cylindrical portion to elastically engage with the locking hole and engage with the notch in the circumferential direction of the flange are continuously provided, By forming the locking hole in the peripheral wall of the highly rigid bottomed cylindrical portion formed in the booster piston, it is possible to suppress the decrease in the rigidity of the booster piston due to the special provision of the locking hole as much as possible. Moreover, when connecting the booster piston and the valve cylinder, the flange of the valve cylinder is housed in the bottomed cylindrical portion so that the notch and the locking hole are aligned, and then the set plate is simply pressed against the flange. Since the locking claws of the set plate can be immediately engaged with the locking holes with, the setting work can be performed simply and quickly, and after the setting, the bottom wall of the bottomed cylindrical portion Abuts the flange with a relatively large contact area, and the flange can be stably sandwiched between the set plate,
There is no risk of fooling around between the valve cylinder and the booster piston. Furthermore, since the relative rotation between the valve cylinder and the booster piston can be reliably regulated by the engagement between the locking claw and the notch, there is no fear that the elastic bead portion on the inner circumference of the booster piston is twisted. Since the airtightness of the elastic bead portion can be maintained satisfactorily for a long time, and moreover, the locking claw which is the fixing means of the set plate is also used as the rotation preventing means between the booster piston and the valve cylinder, the structure is simply that much. Can be contributed to.

[Brief description of drawings]

The drawing shows an embodiment of the present invention. Fig. 1 is a vertical sectional side view of a negative pressure booster, Fig. 2 is an enlarged view of a portion II of Fig. 1, and Fig. 3 is a line III-III of Fig. 2. FIG. 4 is a sectional view, FIG. 4 is a perspective view of the set plate, and FIG. 5 is a sectional view similar to FIG. 2, showing a modified example of the locking hole. B ... Negative pressure booster 2 ... Booster piston, 2a ... Bottom cylindrical portion, 3b ...
... Inner peripheral bead as elastic bead portion, 7 ... Valve cylinder, 7b
...... Flange, 10 ...... Locking hole, 11 ...... Set plate, 12 ...... Locking claw

Claims (1)

[Scope of utility model registration request] 1. An elastic bead portion (3b) integrally provided on an inner peripheral portion of a booster piston (2) is airtightly fitted on an outer periphery of a valve cylinder (7), and a base portion of the valve cylinder (7). Of the booster piston and the valve cylinder in the negative pressure booster, which is formed by sandwiching the flange (7b) connected to the booster piston (2) and the set plate (11) locked to the booster piston (2). In the connection structure, the booster piston (2) is provided with a bottomed cylindrical portion (2a) that accommodates the flange (7b), and the cylindrical portion (2) is formed.
The flange (7b) is brought into contact with the bottom wall of a), and a plurality of locking holes (10) are provided at equal intervals on the peripheral wall of the cylindrical portion (2a), and corresponding to these locking holes (10). A plurality of cutouts (9) are formed on the outer peripheral surface of the flange (7b) at equal intervals, and the set plate (11) has the cutouts (9) when pressed against the flange (7b). A plurality of engaging members which enter between the cylindrical portion (2a) and the cylindrical portion (2a) to elastically engage with the locking hole (10) and engage with the notch (9) in the circumferential direction of the flange (7b). A structure for connecting a booster piston and a valve cylinder in a negative pressure booster, which is characterized in that stop claws (12) are connected in series.