JPH051751Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coupling pipe used in a muffler of an internal combustion engine, for example, and a pipe body for various other uses.

[Conventional technology]

Conventionally, simple pipe bodies used in places where a slight leakage of exhaust gas is allowed, such as the coupling pipe used in the above-mentioned muffler, are generally made by rolling a material plate and butt-welding both ends of the pipe. Alternatively, the two end edges are usually overlapped and fixed by spot welding, fillet welding, or the like.

[The problem that the idea attempts to solve]

However, butt welding like the former method requires more man-hours than spot welding, etc.
Moreover, complicated management is required to set gaps between butt parts and eliminate steps.

On the other hand, in the case of the latter method, in which both ends of the material plates are overlapped and fixed by spot welding, etc., the welding work is easy, but the diameter cannot be determined due to spring back caused by variations in material lots, making it rough. It's a win. Therefore, there are many problems in the case of a pipe such as the above-mentioned coupling pipe, which requires precision in the fitting dimensions with the holes in the partition plate.

The present invention was proposed in view of the above-mentioned problems, and an object of the present invention is to make it possible to easily and inexpensively manufacture a tube body with good dimensional accuracy.

[Means to solve the problem]

In order to achieve the above object, the tube body according to the present invention has the following configuration.

That is, in a tube body 1 formed by rolling one raw material plate, a plurality of locations in the generatrix direction of both circumferential edges of the rolled raw material plate are bent inward in the radial direction, and the opposing bent portions 11a, 12a are brought into close contact with each other, and both circumferential end edges 11 and 12 of the material plates are overlapped and welded inside and outside between the bent portions 11a, 11a, 12a, 12a adjacent in the generatrix direction. shall be.

[Effect]

As described above, positioning in the circumferential direction is achieved by abutting the bent portions 11a, 12a at multiple locations on both ends of the rolled material plate and bringing them into close contact, and in this state, the adjacent bent portions 11a, 11a, 12
By overlapping and welding both end portions 11 and 12 of the material plates between a and 12a inside and outside, it becomes possible to easily manufacture a tube body having a predetermined outer diameter.

〔Example〕

In the illustrated example, bent portions 11a.
2a and the adjacent bent portions 11a, 11
The overlapping portions 11 and 12 between a, 12a and 12a are fixed by spot welding W.

The number and position of the bent portions 11a and 12a are as follows:
They shall be provided as appropriate depending on the length of the tube, and shall be provided at at least two or more locations along the length of the tube.

Further, as shown in FIG. 3, the overlapping portions 11 and 12 are formed so that the inner overlapping piece 12 is recessed inward by the thickness of the plate to form a flat outer peripheral surface. Or the fourth
As shown in the figure, the outer overlapping piece 11 is made to protrude outward to form a flat inner circumferential surface. Either one is fine.

The above-mentioned manufacturing procedure for the pipe body is arbitrary, and for example, raw material plates of a predetermined length are individually formed by roll forming or press forming, or long material plates are formed by roll forming or press forming, and then the required length is formed. It may be manufactured by cutting to size.

[Effect of idea]

As described above, the present invention bends both end edges of a rolled material plate inward in the radial direction, and brings the opposing bent portions 11a and 12a into close contact with each other. Bending part 11
Both ends 1 of the material plate between a, 11a, 12a, 12a
1 and 12 are overlapped inside and outside and welded, circumferential positioning is performed by the bent portions 11a and 12a, and the circumferential length dimension can be set accurately, and the overlapping portions 11 and 12 are The tube body can be easily manufactured by simply welding the tubes 12 to 12, and the tube body having highly accurate outer diameter dimensions can be easily and inexpensively produced.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of a tube according to the present invention, Fig. 2 is a side view of a part of the tube, Fig. 3 is a cross-sectional side view of the overlapping portions at both ends, and Fig. 4 is a view of a modified example of the same. 1 is a tube, 11 and 12 are overlapping portions at both ends, 11 is a cross-sectional side view of the overlapping portions at both ends,
a, 12a are bending portions.

Claims (1)

[Scope of utility model registration request] In the case where a tube is formed by rolling a single raw material plate, multiple points in the generatrix direction of both circumferential edges of the rolled raw material plate are bent inward in the radial direction, and the opposing bent portions are butted against each other. A tube body characterized in that both edges in the circumferential direction of the material plates are overlapped and welded inside and outside between the bent portions adjacent in the generatrix direction.