JPH09242541A - Exhaust pipe manifold connection member manufacturing method - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: For example, an exhaust pipe manifold connecting member used for an exhaust system of an internal combustion engine such as an automobile or a motorcycle, particularly, a manifold connecting member having an asymmetrical shape with respect to a center line thereof has a simple and easy structure.
It is an object of the present invention to provide a manufacturing method that can be manufactured at low cost. A plurality of at least one of upstream and downstream exhaust pipes is provided, and a manifold connecting member (1) for communicating and connecting the upstream exhaust pipe and the downstream exhaust pipe is provided as a single cylindrical body (10).
A method for manufacturing an exhaust pipe multi-connecting member, which is manufactured by forming one end side of the above into a flat trumpet shape by a pressing die 2.
The pushing die 2 is composed of a pair of die pieces 21 and 22 having a substantially semicircular cross section which are openably and closably connected to each other. It is characterized in that it is inserted and the two die pieces 21 and 22 are gradually opened at the rear side in the insertion direction in association with the inserting operation to form a flat trumpet shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an exhaust pipe manifold connecting member used in an exhaust system of an internal combustion engine such as an automobile or a motorcycle.

[0002]

2. Description of the Related Art Conventionally, in an exhaust system of an internal combustion engine as described above, for example, as shown in FIG. 4, exhaust gas from one exhaust pipe P1 on the upstream side is exhausted from a plurality of exhaust pipes P2, P3 on the downstream side.
In some cases, the exhaust from a plurality of exhaust pipes on the upstream side is collected into one exhaust pipe on the downstream side, although not shown in the figure. In that case, the exhaust pipe on the upstream side and the exhaust pipe on the downstream side are generally connected to each other through a multi-part connecting member 1 branched into a multi-forked shape or a multi-part shape.

The above-mentioned multi-purpose connecting member 1 has been conventionally manufactured by various methods. For example, as shown in FIG. 5, the multi-purpose connecting member 1 is divided into upper and lower halves 11 and 12 to face each other. It is known that the peripheral portions 11a and 12a of the mating surfaces are welded to be integrated (see, for example, Japanese Utility Model Laid-Open No. 61-82019). However, in the above-mentioned conventional one, the parts 11 and 12 are divided into two parts and are welded and joined, so that the number of processing steps is large and the cost is high. Moreover, the welded part is exposed to the outside and the appearance is spoiled or the welded part is damaged. However, there is a problem such as corrosion and deterioration of durability.

On the other hand, for example, as shown in FIG.
One cylindrical body 10 is used as a material for the multi-purpose connecting member, one end 10a side of the cylindrical body 10 is formed to have a small diameter by press working, and the other end 10b side is expanded in a tapered shape as shown by a chain line in the figure. There is also known a method of forming a diversified connecting member by forming an opening, making two diametrical directions (vertical directions) of the expanded opening close to each other, and forming into a spectacle frame shape as shown by the solid line in the figure. . However, it is relatively easy to manufacture a diversified connecting member having a symmetrical shape with respect to the center line X-X as shown in FIG. 4 by such a method, but for example, the center line X as shown in FIG. Those asymmetrical with respect to -X cannot be easily manufactured.

Therefore, it is conceivable to form the multipurpose connecting member as shown in FIG. 3 by using, for example, a pressing die.
FIG. 7 shows an example thereof. For example, one end 10a of a cylindrical body 10 as shown in FIG. 7A is formed to have a small diameter as shown in FIG. 7B, and the other end 10b is expanded in a tapered shape. (C) in the opening of the formed end portion 10b.
As shown in (d), an asymmetrical pressing die 20 is inserted to form a flat trumpet shape. Then, the tubular body 10 formed in the flat trumpet shape may be formed into the spectacle frame shape in the same manner as described above.

However, as described above, the pressing die 2
When 0 is pushed into the cylindrical body 10 to form a flat trumpet shape, the asymmetrical pressing die 20 comes into partial contact with the cylindrical body 10 and locally exerts an unreasonable force on the abutting portion of the pressing die 20. As shown in (d) of FIG.
There is a problem that s is buckled or damaged.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems, and is an exhaust pipe multi-connecting member, particularly a center line thereof, which constitutes a collecting part or a branching part of an exhaust pipe as described above. On the other hand, it is an object of the present invention to provide a manufacturing method capable of manufacturing an asymmetrical multi-purpose connecting member with a simple structure and easily and inexpensively.

[0008]

In order to achieve the above object, the method for manufacturing an exhaust pipe manifold connecting member according to the present invention has the following constitution.

That is, at least one of the exhaust pipes on the upstream side and the downstream side has a plurality of pipes, and a manifold connecting member for connecting the exhaust pipes on the upstream side and the exhaust pipes on the downstream side to each other is provided at one end of one cylindrical body. A method for manufacturing an exhaust pipe manifold connecting member, which is manufactured by forming a flat trumpet shape on the side by a pressing die, the pressing die being formed of a pair of die pieces having a substantially semicircular cross section, which are openably and closably connected to each other. , The two die pieces are inserted into the cylindrical body with the rear side in the insertion direction being closed, and the rear sides in the insertion direction of both die pieces are gradually opened in conjunction with the insertion operation to form the cylindrical body into a flat trumpet shape. It is characterized by doing.

[0010]

[Function] The pair of die pieces openably and closably connected as described above are sequentially inserted into the cylinder body with the rear side in the insertion direction being closed,
By making the rear sides of both die pieces open gradually in conjunction with the insertion operation, it is possible to satisfactorily form the cylindrical body into a flat trumpet shape without causing buckling or damage unlike the conventional case. Becomes

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for manufacturing an exhaust pipe manifold connecting member according to the present invention will be specifically described with reference to an embodiment shown in the drawings.

FIG. 1 shows an example of the manufacturing method according to the present invention. As in the conventional case, a cylindrical body 10 as shown in FIG. 1A is used as a raw material, and the cylindrical body as shown in FIG. One end 10a of 10 is formed to have a small diameter in advance by press working or the like, and the other end 10b is formed to be expanded in a tapered shape. The cylinder 1
0 is fixed by a jig or the like not shown in the drawing, and the pressing die 2 is inserted into the tapered opening of the cylindrical body 10 as shown in FIG.

The pushing die 2 comprises a pair of die pieces 21.
・ 22 has a structure in which it is openably and closably connected by a support shaft 23, and each of the die pieces 21 and 22 is formed into a substantially semicircular cross section as shown in FIG. Is formed in. Further, taper surfaces 21a and 22a are formed on the outer peripheral surfaces of the respective die pieces 21 and 22 so as to gradually taper toward the front side in the insertion direction into the cylindrical body 10, and the spindle 23 is provided with the front end side on the front side in the insertion direction. It is provided at an intermediate position between the above-mentioned tip portion and the longitudinal center portion on the slightly rear side.

At least one of the two die pieces 21 and 22 is moved by a pressing machine or the like to be inserted into the cylindrical body 10. In this embodiment, one die piece 21 is omitted in the drawing. It is attached to a movable ram or the like of the machine to move in parallel with the axial direction of the cylinder body 10, and the other die piece 22 is made to follow the die piece 21 via a support shaft 23.

Further, the other die piece 22 is held in a state in which it can be freely opened and closed with respect to the die piece 21 around the support shaft 23, and initially, as shown in FIG.
2 is inserted into the cylindrical body 10 in a state where the rear sides of the two in the inserting direction are in close contact with each other and are closed, and the other die piece 22 is inserted into the cylindrical body 10 in association with the inserting operation of the die piece 21 into the cylindrical body 10. ) Is the one that was automatically opened wide.

That is, as shown in FIG. 1 (c), when the two die pieces 21 and 22 are inserted into the cylindrical body 10 with their rear sides in the insertion direction being in close contact with each other and being closed, both die pieces 21 and 22 are inserted.
The front side in the insertion direction of is open as shown in the figure. In that state, if one die piece 21 is pushed into the cylindrical body 10,
At least one die piece, in the case of the figure, the front side of the lower die piece 22 first comes into contact with the inner surface of the cylindrical body 10 as shown in FIG.

When the die piece 21 is continuously pushed into the cylindrical body 10 in this state, the front end portion of the die piece 22 which is in contact with the inner surface of the cylindrical body 10 is rotated so as to escape to the other die piece 21 side. As a result, the front end corners of the die pieces 22 are prevented from biting into the wall surface of the cylindrical body 10, and the front sides of the two die pieces 21 and 22 are gradually closed by the above-described rotation operation as shown in FIG. At the same time, the rear side gradually opens and the cylinder 1
The 0 tapered opening is gradually deformed from a circular shape to an elliptical shape that is long in the vertical direction.

Further, when the die piece 21 is pushed into the cylindrical body 10, both die pieces 21 and 22 as shown in FIG.
When the front side of the die is further closed and the rear side is further opened, and the die piece 21 enters a predetermined depth in the cylindrical body 10 as shown in FIG. And the rear sides of both die pieces 21 and 22 are fully opened, and the tapered opening 10b of the cylindrical body 10 is formed into a flat trumpet shape.

As described above, the pushing die 2 is composed of a pair of dice pieces 21 and 22 that are openably and closably connected. By pushing both dice pieces 21 and 22 into the cylindrical body 10 and gradually opening them, It can be molded into a flat trumpet shape. Particularly, in the above embodiment, the opening / closing fulcrum (support shaft 23) of both die pieces 21 and 22 is provided slightly rearward of the front end portion in the insertion direction of both die pieces 21 and 22 with respect to the cylindrical body 10, so that one die piece When the die 21 is pushed into the tubular body 10, the other die piece 22 is automatically opened in conjunction with it, so that the inner surface of the tubular body 10 can be smoothly and satisfactorily molded without exerting an unreasonable force. It is possible.

After forming the flat trumpet shape as described above, the flat trumpet-shaped end portion is formed into a spectacle frame shape in the same manner as the conventional example, and a multi-point connecting member as shown in FIG. 3 is formed. The above-mentioned eyeglass frame-shaped forming process may be performed before or after fitting and connecting the exhaust pipes P1 to P3.

It is not always necessary to perform the above-described eyeglass frame-shaped forming process, and the exhaust is performed with the opening of the end portion 10b formed in a substantially oval shape as shown in FIG. 1 (f). Fitting and connecting pipes P2 and P3, both exhaust pipes P
It is also possible to close the gap generated between 2 and P3 with a spacer or the like, or to form abutting portions of adjacent exhaust pipes in the shape of a rectangular tube so that the exhaust pipe is closely fitted in the opening.

[0022]

As described above, according to the manufacturing method of the present invention, an exhaust pipe multi-part connecting member forming a collecting part or a branch part of an exhaust pipe, in particular, a multi-part connecting member asymmetrical with respect to a center line, It is possible to satisfactorily manufacture without partially buckling or damaging as in the conventional case, and it is possible to improve the productivity and the yield of this kind of exhaust pipe manifold connecting member.

[Brief description of drawings]

1 (a) to 1 (f) are explanatory views showing an example of a method for manufacturing an exhaust pipe manifold connecting member according to the present invention.

FIG. 2 is a perspective view of a pushing die.

FIG. 3A is a plan view of an exhaust pipe manifold connecting member according to the present invention. (B) is a sectional view taken along line AA in (a).

FIG. 4 is a plan view showing an example of a conventional exhaust pipe manifold connection member.

FIG. 5 is a perspective view showing an example of a method of manufacturing a conventional exhaust pipe multi-connection member.

FIG. 6 is a perspective view showing another manufacturing method of the conventional exhaust pipe multi-connection member.

7 (a) to 7 (d) are explanatory views in the case of manufacturing the exhaust pipe manifold connecting member with one pushing die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multiple connection member 10 Cylindrical body 2 Pushing die 21, 22 Die piece P1-P3 Exhaust pipe

Claims (3)

[Claims] 1. A multi-way connecting member for connecting at least one of the upstream side and the downstream side exhaust pipes and connecting the upstream side exhaust pipe and the downstream side exhaust pipe to each other at one end of one cylindrical body. A method for manufacturing an exhaust pipe manifold connecting member, which is manufactured by forming a flat trumpet shape on the side by a pressing die, the pressing die being formed of a pair of die pieces having a substantially semicircular cross section, which are openably and closably connected to each other. , The two die pieces are inserted into the cylindrical body with the rear side in the insertion direction being closed, and the rear sides in the insertion direction of both die pieces are gradually opened in conjunction with the insertion operation to form the cylindrical body into a flat trumpet shape. A method for manufacturing an exhaust pipe manifold connecting member, comprising: 2. The exhaust pipe manifold according to claim 1, wherein one end side of the tubular body is preliminarily expanded into a tapered shape, and then the tubular body is formed into a flat trumpet shape by the pushing die. A method for manufacturing a connecting member. 3. The opening and closing center position of both the die pieces is provided slightly rearward of the front end portion in the insertion direction into the tubular body so that both die pieces are inserted into the tubular body in a state where the rear side in the insertion direction is closed. The front side in the insertion direction of both die pieces is opened, and the front side in the insertion direction of both die pieces is gradually closed along the tapered surface by pushing one die piece into the tapered cylinder body in that state, 3. The method for manufacturing an exhaust pipe multi-connection member according to claim 2, wherein the rear sides of the two die pieces in the inserting direction are automatically gradually opened so that the cylindrical body is formed into a flat trumpet shape.