JPH0231258Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a welded portion of a double-layered pipe and a flange when a flange is welded and fixed to the outer circumferential side of a double-layered pipe consisting of an inner pipe and an outer pipe. Regarding the structure of

〔Technical field〕

A double-layered pipe consisting of an inner pipe and an outer pipe is used, for example, as an exhaust pipe of an internal combustion engine, and is used to reduce noise by creating an air layer interposed between the inner pipe and the outer pipe. When a flange is welded and fixed to this double-layer pipe, conventionally, as shown in Figs. 1 and 2, the flange 1 and the outer pipe 2 are fixed by the weld penetration 3, and the outer pipe 2 and the inner pipe What is tube 4?
It was simply inserted by press-fitting or the like. However, when the double-layer pipe 5 is used, for example, as an exhaust pipe, it can reduce the weight of the engine,
In order to reduce costs, both the inner tube 4 and the outer tube 2 are usually constructed with small wall thicknesses, so it is disadvantageous in terms of strength to weld and fix the flange 1 and the outer tube 2 alone. That is, as shown by the arrow in Fig. 2, the force applied from the flange 1 to the double-layered pipe 5 is applied near the welded part, and since the wall thickness of both the inner and outer pipes is not very large, the strength is usually weakest in this area. There was a risk that the strength would be insufficient.

[Purpose of invention]

The present invention aims to improve the strength of the welded portion when welding a flange to the outer peripheral side of a double-layer pipe in order to solve the above-mentioned problems.

[Structure of the idea]

The welded part structure of the double-layered pipe and flange of the present invention that meets this purpose is to fit a flange into a double-layered pipe consisting of an inner pipe and an outer pipe, and to attach the flange at a part opposite to the end of the double-layered pipe. In a welded part structure of a two-layered pipe and a flange welded to the outer periphery of a two-layered pipe, the inner pipe, outer pipe, and flange are all fixed to each other by welding.

[Effect of invention]

In such a structure, the inner tube, outer tube, and flange are welded to each other at the same time, or near the welded portion of the outer tube and flange, so that the inner tube and outer tube are welded together at the welded portion. The force applied from the flange is received by a large part of the integrated wall thickness, and the strength of the welded part is improved compared to the conventional case where the outer tube and inner tube are alone.

[Effect of idea]

Since the strength of the welded portion is sufficiently improved, it is possible to eliminate weak points in strength that have conventionally been caused by welding flanges. In addition, even with a double-layered pipe with a small wall thickness, by welding and fixing the inner and outer pipes, the strength near the flange weld can be sufficiently improved, so the required strength can be maintained and the equipment The weight and cost can be reduced.

〔Example〕

Hereinafter, preferred embodiments of the welded structure of the double-layer pipe and flange of the present invention will be described with reference to the drawings.

FIGS. 3 and 4 show a welded structure of a double-layer pipe and a flange according to a first embodiment of the present invention. The two-layer tube 10 is composed of an inner tube 11 and an outer tube 12, and the inner tube 11 is inserted into the outer tube 12 by a method such as press fitting. End portion 11a of inner tube 11
protrudes beyond the end surface 12a of the outer tube 12, and a flange 13 is fitted around the outer periphery of this protrusion 11a. An appropriate space is provided between the side surface 13a of the flange 13 on the outer tube 12 side and the end surface 12a of the outer tube 12. End surface 12a of outer tube 12
, the outer peripheral surface of the inner tube 11 , and the side surface 1 of the flange 13
Welding penetration is performed from the outer circumferential side of the two-layer tube by arc welding or the like into the space 14 surrounded by the outer tube 3a, filling the space 14 and forming the end surface 1 of the outer tube 12.
2a, a weld bead 15 with penetration is formed on the outer peripheral surface of the inner tube 11 and the side surface 13a of the flange 13. Therefore, the inner tube 11, outer tube 12, and flange 13 are fixed to each other via the weld bead 15.

In the structure of the welded part between the two-layer pipe 5 and the flange configured in this way, the weld bead 15 formed on the outer periphery of the inner pipe 11 is attached to the two-layer pipe for all of the outer pipe 12, inner pipe 11, and flange 13. Since the weld penetration is from the outer circumferential side, the outer tube 1
2. The inner tube 11 and the flange 13 are integrally connected and fixed. By integrating the inner tube 11 and the outer tube 12, the inner tube 11 and the outer tube 12 are separated at the welding part.
It will have the same strength as a single tube with the total wall thickness of , and the force applied from the flange 13 will be borne by the welded part where the inner tube 11 and outer tube 12 are integrated. . Therefore, as in the past,
The strength of the welded portion is improved by integrating the outer tube and the inner tube, compared to the case where the outer tube and inner tube are supported individually. Therefore, compared to the conventional case where only the flange and outer tube were welded, assuming that the wall thickness of the inner tube and the outer tube are approximately the same, the strength is almost twice as strong, and the strength of the welded part and the vicinity of the welded part is sufficient strength is guaranteed.

Next, FIGS. 5 and 6 show a welded structure of a double-layer pipe and a flange according to a second embodiment of the present invention. In this embodiment, the flange 13 is fitted onto the outer circumference of the outer tube 12, and a groove 16 consisting of a V-groove is formed on the outer circumferential surface of the outer tube 12. A weld bead 17 is formed by melting the entire wall thickness of the outer tube 12 and the outer peripheral surface of the inner tube 11.

In such a welded part structure, as in the first embodiment, the weld bead 17 penetrates from the outer circumferential side of the double-layered pipe, so that the flange 13 and the outer pipe 1 are bonded together at the welded part.
2. The inner tube 11 is integrally connected, and the flange 13
The force applied from the outer tube 12 and the inner tube 1 which are integrally connected
It is supported by the welded part 1. Therefore,
The strength of the welded part is sufficiently improved compared to when the outer tube and inner tube are used alone. Other configurations and operations are similar to those of the first embodiment.

Next, FIGS. 7 and 8 show a welded structure of a double-layer pipe and a flange according to a third embodiment of the present invention. In this embodiment, the flange 13 is the outer tube 1.
A weld bead 18 having weld penetration is formed on the side surface 13a of the flange 13 and the outer circumferential surface of the outer tube 12. The outer tube 12 and the inner tube 11 are fusion-welded to each other at a position 19 near the weld bead 18 on the inner and outer circumferential surfaces by spot welding or seam welding.

In such a welded part structure, the flange 1
3. The outer tube 12 and the inner tube 11 are not fixed at the same time with the same weld bead, but by fixing with the weld bead 18, spot welding, or seam welding, the flange 13, outer tube 12, and inner tube 1 are indirectly fixed.
1 will be welded and fixed to each other. Therefore, as in the first embodiment, the force applied from the flange 13 is borne by the integrally connected outer tube 12 and inner tube 11, improving the strength of the welded portion. Other configurations and operations are similar to those of the first embodiment.

As is clear from the above explanation, when using the welded part structure of the double-layered pipe and flange of the present invention, the flange, outer pipe, and inner pipe are welded and fixed to each other at the welded part, so the strength of the welded part is In addition, even if the wall thickness of the inner and outer tubes is not very large, the strength of the welded part can be sufficiently guaranteed, and the necessary strength can be maintained. At the same time, it is possible to reduce the weight and cost of the device.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a conventional welded part between a double-layer pipe and a flange, Fig. 2 is a partially enlarged cross-sectional view showing the part shown in Fig. 1, and Fig. 3 is a double-layer pipe according to the first embodiment of the present invention. FIG. 4 is a partially enlarged sectional view showing the part shown in FIG. 3; FIG. 5 is a welded portion of a double-layered pipe and flange according to the second embodiment of the present invention. FIG. 6 is a partially enlarged sectional view showing the part shown in FIG. 5; FIG. 7 is a vertical sectional view showing the welded structure of the double-layer pipe and flange according to the third embodiment of the present invention. , FIG. 8 is a partially enlarged cross-sectional view showing the part shown in FIG. 7. 10...Double layer pipe, 11...Inner pipe, 12...Outer pipe, 13...Flange, 15, 17, 18...Weld bead, 16...Grove, 19...Position of spot welding or seam welding .

Claims (1)

[Claims for Utility Model Registration] (1) A flange is fitted to a two-layered pipe consisting of an inner pipe and an outer pipe, and the flange is welded to the outer periphery of the two-layered pipe at a portion opposite to the end of the two-layered pipe. A welded part structure of a two-layered pipe and a flange, characterized in that the inner pipe, the outer pipe, and the flange are all fixed to each other by welding. (2) The structure of a welded portion of a double-layered pipe and a flange according to claim 1, wherein the inner pipe, outer pipe, and flange are simultaneously fixed by welding penetration from the outer circumferential side of the double-layered pipe. (3) Practical use in which the outer tube and flange are fixed by welding penetration from the outer circumferential side of the two-layer tube, and the inner tube and outer tube are fixed by either spot welding or seam welding at a position near the fixed part. A welded structure of a double-layer pipe and a flange according to claim 1 of the patent registration.