JPH0110290Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a booster, and more particularly to the structure of a pair of shells that tightly clamp the outer circumference of a diaphragm.

Boosters such as brake boosters and clutch boosters commonly have a pair of shells forming an outer shell, and a space held between the pair of shells to define a space inside the outer shell. It is equipped with a diaphragm. To explain the configuration of the brake booster 11 shown in FIG. 4, which is a conventional structure of the holding part between the diaphragm and the shell, each outer circumferential end of the pair of shells 12 and 13 constituting the outer shell body is Flange parts 14 and 15 are formed facing each other, and the outer peripheral part of the diaphragm 16 is sandwiched between the two flange parts 14 and 15 to connect and fix both shells 12 and 13. Therefore, in this type of brake booster, the diameter is further enlarged by the flange portions 14 and 15 compared to the actual diameter of the shell that determines its output, which hinders its miniaturization. There was a drawback.

In view of these drawbacks, the present invention forms an annular groove opening in the radial direction in one shell so that the outer circumferential part of the diaphragm can be closely held between the inner circumferential surface of the annular groove and the inner circumferential surface of the other shell. The purpose is to provide a compact booster that does not require the above-mentioned flange portion and does not impair the effective diameter of the booster. A first annular bulge that protrudes and curves inward in the radial direction, and a second annular ridge that inverts and bulges out in a loop shape from the first annular bulge inward in the axial direction and outward in the radial direction and folds back. a first shell consisting of a substantially disc-shaped single plate body, the first and second annular ridges forming an annular groove opening radially outward at the outer peripheral edge; a diaphragm whose outer periphery is fitted into an annular groove, and a second shell made of a bottomed cylindrical body whose outer periphery is fitted into a cylindrical opening of the first shell, the second shell having a cylindrical shape. The protrusions formed on the outer periphery of the first shell are brought into contact with the plurality of notches formed at the opening end, and the plurality of engagement claws that come into contact with the outside of the first shell are brought into contact with the cylindrical opening of the second shell. The outer periphery of the diaphragm is provided between the inner circumferential surfaces having a substantially triangular cross section formed between the annular groove portion and the cylindrical portion. The reason is that the parts are held tightly together.

The present invention will be explained below with reference to the illustrated embodiments.
The brake booster 1 includes a first shell 2 as a rear shell and a second shell 3 as a front shell. The first shell 2 is generally formed into a disk shape, and as shown in FIG. The culm forms a loop-shaped bent part that protrudes outward, and with this configuration, the first annular bulge protrudes and curves inward in the radial direction from the peripheral edge that is formed at the outer peripheral edge. a, and a second annular bulge b which is inward in the axial direction and bulges in a loop shape and folded back in the radial direction outward from the culm in the radial direction. An annular groove 5 opened radially outward is formed for engaging the outer circumference. On the other hand, the second shell 3 is generally formed into a cylindrical shape with a bottom, and the cylindrical portion 6 on the opening side is provided with a smooth stepped portion 7 to form a cylindrical shape. The inner diameter of the opening is made slightly larger than the inner diameter of the opening. In addition, as shown in FIG. 2, notches 8 are formed at multiple locations at equal intervals on the circumferential surface of the opening end of the second shell 3, and a portion of the circumferential surface on which no notches 8 are formed. A plurality of engaging pawls 9 are formed by bulging out inward in the radial direction. At this time, the axial distance between the end surface of the notch 8 and the inner end surface of the engaging claw 9 is made to match the thickness of the first shell 2.

Furthermore, the diameter of the outer circumferential end of the first shell 2 extending in the radial direction is made to match the inner diameter of the trapezoidal part outward from the stepped part 7 formed in the second shell 3. A protruding portion 10 that engages with the notch portion 8 is formed.

Note that the other configurations and operations are the same as those of conventionally known brake boosters, so a description thereof will be omitted.

In order to connect the first shell 2 and second shell 3 having the above configuration, first, the outer circumference of the diaphragm 4 is fitted into the annular groove 5 of the first shell 2, and then the With the protruding portion 10 aligned with the notch 8 formed in the second shell 3, the first shell 2 is fitted into the second shell 3 until the protruding portion 10 abuts the notch 8. In this state, if the engaging pawl 9 is formed by expanding radially inward using a press machine, the first shell 2 is held between the notch 8 of the second shell 3 and the engaging pawl 9. and is connected and fixed to the second shell 3. In addition, in this state, the outer peripheral part of the diaphragm 4 is
The inner circumferential surface of the cylindrical portion 6 and the inner surface of the annular groove portion 5 of the first shell 2 are closely held to keep the portion airtight.

In the above embodiment, the cylindrical portion 6 is formed with a smooth stepped portion 7 for the purpose of facilitating assembly, stabilizing the dimensions of the diaphragm contact portion during press molding, and improving sealing performance. Can be omitted.

As described above, the present invention includes a first shell having an annular groove that opens outward in the radial direction, a diaphragm whose outer periphery is fitted into the annular groove, and a cylindrical portion that receives the annular groove of the first shell. The first shell and the second shell are connected and the outer circumference of the diaphragm is closely held between the annular groove and the inner circumferential surface of the cylindrical part, so that the booster has a It is now possible to set the maximum diameter to the outer diameter of the cylindrical part of the second shell, which makes it possible to make the booster smaller compared to the conventional booster that formed a flange, and to increase the effectiveness of the booster. The effect is that the diameter can be secured.

Particularly in the present invention, the first shell is provided with a first shell that is curved and protrudes radially inward from the peripheral edge of the first shell.
This first annular bulge is provided with an annular bulge and a second annular ridge that inverts and bends back in a loop shape on the axial side and on the radially outward side of the culm from the first annular ridge. When the outer periphery of the diaphragm is sandwiched between the annular groove formed on the outer edge of the shell and the cylindrical opening of the second shell, the swollen end of the outer periphery of the diaphragm is formed between the annular groove and the cylindrical opening. The clamping state is such that the first annular bulge inverts and bulges out, approaches the cylindrical part, and folds back into the second annular bulge. As a result, it is elastically supported, and an extremely reliable and stable clamping and gripping mode can be achieved against the load repeatedly applied in the axial direction of the booster. In particular, as mentioned above, the first shell has a continuous inverted single plate configuration consisting of the first annular bulge and the second annular ridge that inverts and bulges out in a loop shape and folds back. When negative pressure is introduced into the interior, the acting force acting on the first shell acts in the direction of reducing the cross-sectional area of the above-mentioned fitted portion, which has a generally triangular cross section, so that the first shell is clamped by the fitted portion. The outer circumferential portion of the diaphragm receives a force in the compressive direction, and can provide extremely excellent airtightness between the first and second shells. Moreover, the first shell having the first and second ridges has its own structural strength enhanced by these ridges, and can be easily formed into a single piece by pressing a relatively thin plate. It has many advantages.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG.
Fig. 2 is a right side view of Fig. 1, Fig. 3 is an enlarged sectional view of the main part of Fig. 1, and Fig. 4 is a sectional view showing an example of a conventional device. . 1... Brake booster, 2... First shell,
3...Second shell, 4...Diaphragm, 5...
Annular groove part, 6...Cylindrical part, a...First annular ridge part, b... Second annular ridge part.

Claims (1)

[Scope of utility model registration request] A first curved part protruding radially inward from the peripheral edge.
and a second annular bulge that inverts and bends back in a loop shape axially inward and radially slightly outward from the first annular bulge,
A first shell is formed of a single, substantially disc-shaped plate having an annular groove opened radially outward at its outer peripheral edge by the first and second annular ridges; a diaphragm fitted with the first
a second shell made of a bottomed cylindrical body that fits the annular groove of the shell into the cylindrical opening, and a plurality of notches formed at the cylindrical opening end of the second shell;
A plurality of engaging pawls are provided to protrude from the cylindrical opening end of the second shell so that the protrusions formed on the outer periphery of the shell are brought into contact with each other, and a plurality of engaging claws that are brought into contact with the outside of the first shell are provided to protrude from the cylindrical opening end of the second shell. 2 shells are engaged and connected, whereby the outer peripheral part of the diaphragm is tightly clamped between the inner peripheral surfaces having a substantially triangular cross section formed between the annular groove part and the cylindrical part. Device.