JPH0134794Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention mainly relates to a fixing structure at the end of a multilayer spiral tube of a blade used for the exterior of an automobile exhaust pipe system.

Conventionally, there are two typical examples of fixation at the edge of a blade used for the exterior of an automobile exhaust pipe system, as described below.

That is, as shown in FIG.
A short pipe 3 is inserted at the very end, the outer periphery is connected by welding, and one end of the blade 1 which surrounds the outer periphery of the spiral pipe 2 is extended to the upper part of the short pipe 3 and further fixed to the upper outer periphery. A ring 4 is fitted onto the outside, and these overlapping portions 5 are fixed by spot welding or the like.

Moreover, as shown in FIG. 2, the spiral tube 2a and the blade 1
In order to provide a gap between them, fixing rings 4a, 4a, which are larger than the outer diameter of the spiral tube 2a by the amount of the gap, are fitted onto the outer periphery of the short tubes 3a, 3a fixed in a cantilevered manner to both ends of the spiral tube 2, facing each other. The blade 1 is interposed between them, and one end is clamped between the fixing ring 4a and the ring-shaped belt 6, and the other end is similarly attached to the cylindrical ring 7 and the belt 6 fitted to the fixing ring 4a. It is clamped and fixed by spot welding, etc.

The fixing rings 4a, 4a and the short pipes 3a, 3a and the cylindrical ring 7 and the fixing ring 4a are each fixed by intermittent welding.

Conventionally, the blade 1 was fixed with the above structure, which increased the number of parts and the number of man-hours, which hindered the reduction in production costs.

Therefore, this invention addresses the above-mentioned problems by omitting the conventional short tube 3a of the belt 6 and the cylindrical ring 7, thereby simplifying the fixing of the blade.

Hereinafter, specific embodiments of this invention will be described with reference to the drawings.

FIG. 3 is a sectional view showing an embodiment of this invention, which consists of a plastically deformable cylindrical body 8, a multilayer spiral tube 2c fitted into it, and an end portion of a blade 1 interposed therebetween. The cylindrical body 8 has a large diameter part 9 on one side that overlaps with the spiral tube 2c, and a small diameter part 10 on the other side for connecting with other materials, and is formed into one body by press working or the like. Ru.

Further, a press machine is applied between 3 and 4 pitches along the valley groove 11 on the outer periphery of the helical tube 2c into which the outer periphery of the large diameter portion 9 of the cylindrical body 8 that has been polymerized to a predetermined length (3 to 4 times the helical tube pitch) is inserted. By causing extrusion plastic deformation, the members of the overlapping portion including the blade 1 are brought into pressure contact with each other, thereby ensuring airtightness.

In addition, a plastic sealing material 13 is applied between each of the overlapping members, that is, a gap 12 formed between the blade 1 and the trough of the spiral tube 2c, and a plastic sealing material 13 between the blade 1 and the cylindrical body 8.
Further airtightness can be ensured by filling the container with .

The dotted line shown in FIG. 3 shows the blade 1a secured in a relaxed state.

This is used when a gap is provided between the blade 1a and the multilayer spiral tube 2c and a heat insulating material is loaded therein.

Since this invention consists of the above structure, the following effects can be expected.

By changing from the conventional blade fixing structure with many parts to the structure of this invention with fewer parts,
The manufacturing cost of parts can be reduced, and welding work is no longer necessary because the fixing method is changed from conventional welding to press processing only.

Furthermore, by pressing and deforming the multilayer spiral tube along the groove portions for several pitches, the overlapping portion becomes in a state similar to that of screwing together, and is fixed more firmly than ordinary flat pressure bonding.

Furthermore, as mentioned above, in order to create a gap between the blade and the multilayer spiral tube, conventional parts are not required, and the length of the blade is simply increased by the required amount.
It is only necessary to fix the ends in a relaxed state, which is a significant difference in structure simplification compared to the conventional example, and can greatly contribute to reducing the number of man-hours.

Furthermore, the airtightness of the polymerization area can be easily achieved by using a sealant, and there are no performance problems.

As described above, the present invention can be expected to have practical beneficial effects in terms of materials, man-hours, and quality.

[Brief explanation of the drawing]

The first is a cross-sectional view showing a conventional blade fixing structure.
Fig. 2 is a sectional view of a conventional blade fixing structure in which a gap is provided between the blade and the helix, and Fig. 3 is an example of the fixing structure at the end of the multilayer spiral tube of the blade according to this invention. FIG. Code, 1...Blade, 2...Multilayer spiral tube,
8... Cylindrical body, 11... Valley groove, 14... Overlapping part.

Claims (1)

[Scope of utility model registration request] A cylindrical body 8 that can be plastically deformed has a multilayer spiral tube 2 inserted therein, and a blade tip is inserted with a predetermined width into an overlapping part 14 of a predetermined length, and the outer periphery of the overlapping part 14 of the cylindrical body 8 is covered with the multilayer spiral tube 2. A fixing structure of a blade at the end of a multilayer spiral tube, in which the blade 1 is airtightly clamped by pressing and deforming the spiral tube 2 in a spiral shape along the valley groove 11 portion.