JP2550514Y2 - Pneumatic booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a pneumatic booster used for a brake system of a vehicle or the like.

(Prior Art) Conventionally, an example of a pneumatic booster is disclosed in
There is the one shown in Japanese Patent Publication No. 70. In this device, a power piston having a diaphragm is arranged in a housing composed of a front shell and a rear shell, and the inside of the housing is defined by the diaphragm and the power piston as a constant pressure chamber and a variable pressure chamber. The power piston is advanced by the differential pressure generated in the above, and the boosted thrust is output. Further, each of the front shell and the rear shell has a cylindrical portion, a flat central end wall formed perpendicular to the axial direction of the cylindrical portion, and a truncated cone portion connecting the central end wall and the cylindrical portion. The rigidity of the front shell and the rear shell is increased by forming a flat outer peripheral end wall orthogonal to the axial direction of the cylindrical portion between the truncated conical portion and the cylindrical portion.

(Problem to be Solved by the Invention) By the way, in the above-mentioned truncated conical portion of the pneumatic booster, the taper angle is set small in order to secure a large volume without increasing the axial dimension of the device, that is, Since it is set in a state very close to the direction orthogonal to the axial direction, it cannot be formed to extend in the axial direction of the cylindrical portion to secure volume, etc., and has a predetermined taper so as to be substantially orthogonal to the axial direction. Therefore, the angle formed between the outer peripheral end wall and the truncated conical portion is increased, so that the outer peripheral end wall and the truncated conical portion have a substantially flat plate shape as a whole. For this reason, the effect of improving the rigidity by forming the outer peripheral end wall was small.
In addition, if the outer peripheral end wall is set to be longer in the radial direction, the angle formed between the outer peripheral end wall and the truncated conical portion can be increased, but such a setting is difficult due to the shape of the power piston. Was.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic booster capable of obtaining a large rigidity with a simple configuration and achieving a reduction in size and weight.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a constant pressure chamber and a variable pressure chamber are defined by a diaphragm in a housing including a front shell and a rear shell, and the diaphragm is attached to a valve body. A pneumatic type in which the power piston is held by a power piston, and a valve mechanism provided in the valve body is operated to advance the power piston by a differential pressure generated between the constant pressure chamber and the variable pressure chamber to output a boosted thrust. In the booster, the rear shell has a tubular portion that slides and guides the valve body, and a taper that extends in a radial direction of the valve body while an inner peripheral side is continuous with the tubular portion and an outer peripheral side is inclined toward the front shell side. The tapered portion is provided on the outer peripheral side of the tapered portion and holds the outer peripheral bead portion of the diaphragm. Portion, a tapered portion main body continuous with the cylindrical portion, and an annular rib provided continuously with the outer peripheral folded portion and the tapered portion main body, the annular rib is open to the front shell side. In addition, the valve body is configured so as to protrude rearward relative to the tapered portion main body in the axial direction of the valve body.

(Operation) According to the present invention, an annular rib is formed continuously on the outer peripheral folded portion and the tapered portion main body, and the annular rib is open to the front shell side and is smaller than the tapered portion main body in the axial direction of the valve body. To be convex to the rear side to reduce the angle between each of the radially inner and outer side wall portions of the annular rib and the tapered portion main body so that when a force is applied to the tapered portion. The radially inner and outer side walls increase the strength of the rear shell against the force pulled toward the front shell.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a housing composed of a front shell 2 and a rear shell 3.
Inside, it is attached to the hollow valve body 10, and
A power piston 5 having a diaphragm 4 is provided, and a constant pressure chamber 7 in which the inside of the housing 1 is connected to a negative pressure source (not shown) via a negative pressure connection pipe 6 by the diaphragm 4 and the power piston 5 and a valve mechanism 8 described later. And a variable pressure chamber 9 which can communicate with the outside through the constant pressure chamber 7.

The hollow valve body 10 has a first passage 11 communicating the outside with the variable pressure chamber 9 and a second passage 12 communicating the constant pressure chamber 7 with the variable pressure chamber 9. ,
The valve mechanism 8 for opening and closing the second passages 11 and 12 is housed therein. An input rod 13 connected to a brake pedal (not shown) is inserted into the internal space of the valve body 10 so as to be able to move forward and backward and to operate the valve mechanism 8 by moving forward and backward. In the initial state (in a state where the brake pedal is not depressed), the constant pressure chamber 7 and the variable pressure chamber 9 communicate with each other via the valve mechanism 8 to have a negative pressure. As a result, the communication between the constant pressure chamber 7 and the variable pressure chamber 9 is cut off, while the variable pressure chamber 9 communicates with the outside and the atmosphere is introduced into the variable pressure chamber 9, causing a pressure difference with the constant pressure chamber 7, whereby the power piston 5 and the valve body 10 moves forward with a large force, and a large thrust is transmitted to an output rod provided on the front side of the valve body 10.

The rear shell 3 is provided with a cylindrical portion 14 for slidingly guiding the valve body 10, and is provided with a tapered portion 15 which is inclined to the front shell 2 side and extends in the radial direction so as to be continuous with the cylindrical portion 14. . On the outer peripheral portion of the tapered portion 15, an outer peripheral folded portion 17 for gripping an outer peripheral bead portion 16 formed on the outer peripheral portion of the diaphragm 4 is formed by being bent inside the housing 1 and further folded outside the housing 1. ing. In a state where the outer peripheral folded portion 17 grips the outer peripheral bead portion 16 of the diaphragm 4, the rear shell 3 is fixed by pressing the distal end 17 a of the outer peripheral folded portion 17 against the caulking projection 18 provided at the distal end of the front shell 2. At the same time, the outer peripheral portion of the diaphragm 4 is held.

An annular rib 19 which is curved to open to the front shell 2 side is formed on a portion of the tapered portion 15 which is continuous with the outer peripheral folded portion 17 on the outer peripheral portion of the tapered portion 15 so as to protrude to the outside of the housing 1.

In the pneumatic booster configured as described above, the annular rib 19 is formed on the tapered portion 15 so that the annular rib 19 is formed.
The cylindrical portion 14 in the side wall portion 19a and the tapered portion 15
The angle θ formed by a portion (taper body, not shown) continuous with the front shell 2 is smaller than that of the above-described conventional one, and the tensile strength toward the front shell 2 increases. Here, the tapered portion 17b of the outer peripheral folded portion 17 and the radially outer side wall portion 19b of the annular rib 19 are preferably substantially perpendicular to the tapered portion 15.

Further, since the annular ribs 19 are formed continuously to the outer peripheral folded portion 17, the lengths of the portion 17b and the side wall portion 19b become longer by that amount, so that the rigidity is improved as a whole.

In general, the rear shell is obtained by drawing or the like using a die and a punch.
The rear shell 3 having 19 has a die and a punch in which a groove having a shape corresponding to the annular rib 19 and a protrusion having a shape corresponding to the groove are formed, respectively, as compared with a case where the one having no annular rib 19 is obtained. Obtained by using For this reason, a large modification of the die and the punch is not required, and a cost increase is not involved in obtaining the rear shell 3 having a large rigidity. In addition, since the die and the punch are rarely modified, the modification can be completed in a short time.

Further, since the strength of the rear shell 3 can be improved as described above, the thickness of the rear shell 3 can be reduced, so that the size and weight of the rear shell 3 can be reduced.

It should be noted that an arrangement may be made such that an annular rib is further formed on the tapered portion 15 apart from the outer peripheral folded portion 17 to improve the rigidity of the rear shell 3.

(Effects of the Invention) According to the present invention, an annular rib is formed continuously to the outer peripheral folded portion and the tapered portion main body, and the annular rib is open to the front shell side and is tapered in the axial direction of the valve body. As a result, the angle formed between the radially inner and outer sidewalls of the annular rib and the tapered portion main body is reduced, and the radially inward of the annular rib is reduced. In addition, the outer side walls contribute to the improvement of the tensile strength toward the front shell, and the tensile strength of the rear shell toward the front shell increases.

Further, since the strength of the rear shell can be improved as described above, the thickness of the rear shell can be reduced, the size and weight can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a pneumatic booster according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a main part of the pneumatic booster. 1 ... housing, 2 ... front shell, 3 ... rear shell, 4 ... diaphragm, 5 ... power piston,
7 ... constant-pressure chamber, 9 ... variable-pressure chamber, 16 ... peripheral bead part, 17
... Outer fold, 19 ... Annular rib.

Claims (1)

(57) [Scope of request for utility model registration] 1. A valve comprising a front shell and a rear shell which are defined by a diaphragm into a constant pressure chamber and a variable pressure chamber, and the diaphragm is held by a power piston mounted on a valve body. In a pneumatic booster that operates a mechanism to output a boosted thrust by advancing a power piston by a differential pressure generated between the constant pressure chamber and the variable pressure chamber, the rear shell slides the valve body to guide the valve body. And a tapered portion that extends radially of the valve body while the inner peripheral side is continuous with the tubular portion and the outer peripheral side is inclined toward the front shell side, and the tapered portion is an outer peripheral side of the tapered portion. An outer peripheral fold that is provided at the outer peripheral bead portion of the diaphragm to hold an outer peripheral bead portion; a tapered portion main body that is continuous with the cylindrical portion; Consists of a circular rib provided parts and continuously to the tapered portion main body, the annular rib,
A pneumatic booster configured to be open to the front shell side and to be convex toward the rear side relative to the tapered body in the axial direction of the valve body.