JP2000140971A - String made of metallic fine wire and cushion for double exhaust tube using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a cost for use by cutting it in length corresponding to the shape of mating parts, making the heat-resistant metallic fine wire which has been composed or woven in a string shape after compressing it to form into a slender shape. SOLUTION: A heat-resistant metallic fine wire (a) such as a stainless steel wire, etc., which has been knitted in a cylindrical shape is made flat, wound in a roll shape for use. By compressing a fed edge part so as to have a high density by a circular shape die 1, by making it a waved flat shape after making it pass through waved rollers 2, and by making it pass through recessed surface rollers 3, an almost circular cross section is obtained. Further, by making it pass through circular rollers 4, it is made to have a rectangular cross section, and is passed through a square die 5. Finally, by making it pass between a lower side roller 6 having a flat outer peripheral surface and an upper side roller 7 with a projecting part 8 formed in the center of its outer peripheral surface, an elastic string C made of the metallic fine wire is continuously manufactured, whose cross section having a recessed part (d) in its center is almost of a recessed type. The string C made of a metallic fine wire is wound on the whole periphery after cut to proper length, and the recessed part (d) is fixed by spot welding for use.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin metal cord used for elastically supporting a part related to an exhaust pipe of an automobile engine and a double exhaust pipe using the same.

[0002]

2. Description of the Related Art In recent years, in order to improve the exhaust gas purification level of automobiles using a catalytic converter, it has become necessary to increase the heat retaining effect of exhaust pipes, and double exhaust pipes have been adopted.

In this double exhaust pipe, since the inner pipe is exposed to a higher temperature than the outer pipe and the thermal expansion increases, if the both ends of the outer pipe are fixed to the inner pipe by welding, distortion may occur and breakage may occur. There is.

Therefore, conventionally, the outer pipe is fixed to the inner pipe by welding only at one end of the double exhaust pipe, and as shown in FIG. 5A, a heat-resistant metal thin wire a such as a stainless steel thin wire is formed into a cylindrical shape. By knitting the knitted fabric on the outside and forming it into a ring shape and compressing and molding it, a ring-shaped cushion b shown in FIG. 3B is interposed between the inner tube and the outer tube at the other end of the double tube. Thus, the difference in thermal deformation between the inner tube and the outer tube is absorbed, and collision between the two tubes due to vibration is prevented.

[0005]

However, in such a cushion, if the diameter of the double exhaust pipe is different, the diameter of the knitted fabric must be changed, and the compression mold must be changed, which increases the cost. There was a problem of becoming.

[0006]

Means for Solving the Problems, Functions and Effects As means for solving such problems, the metal thin wire cord according to the first aspect of the present invention is formed by compression-molding a knitted or woven thin heat-resistant metal wire. And by cutting it to an appropriate length, it can be wound around the inner pipe of a double pipe of an arbitrary diameter, so that the cost can be reduced. In addition, strip-shaped thin metal wires are used as cushioning materials around the exhaust pipe where heat resistance is required, and these thin metal wires are also cut into appropriate lengths. It can be used by doing.

According to the second aspect of the present invention, a thin heat-resistant metal wire knitted in a tubular shape is formed into a long and thin shape by compression molding, and thus has excellent elasticity.

[0008] The thin metal wire string of the third aspect of the present invention has a substantially concave cross section in the thin metal wire string of the first or second aspect of the present invention. If the electrode is pressed against the depressed part when performing spot welding, the surrounding swelling or hardening due to spot welding does not occur on the flat part that becomes the sliding surface with the outer tube, and the outer part due to thermal deformation Sliding with the tube is performed smoothly.

According to a fourth aspect of the present invention, there is provided a cushion for a double exhaust pipe according to the first, second or third aspect of the present invention. Because of the intervention, the above-described thin metal wire string can be used effectively.

In the double exhaust pipe cushion according to the fifth aspect of the present invention, since welding is limited to spot welding in the fourth aspect of the invention, the welding operation can be performed quickly.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a manufacturing process of a thin metal wire string according to the present invention, in which a heat-resistant thin metal wire a such as a stainless steel thin wire knitted into a tubular shape is flattened and wound into a roll, and the unreeling end thereof is used. Is squeezed through a circular die 1 to a high density, then is passed through a corrugating roller 2 to obtain a flat shape with corrugations. After passing through a rectangular die 5 as a cross section, finally pass between a lower roller 6 having a smooth outer peripheral surface and an upper roller 7 having a convex portion 8 formed at the center of the outer peripheral surface, as shown in FIG. As shown in an enlarged view, a thin metal wire string c having a concave section d at the center and having a substantially concave cross section is manufactured continuously.

FIG. 2 shows a double exhaust pipe 10 in which an outer pipe 12 is fitted to an inner pipe 11. A reduced diameter section 12a at one end of the outer pipe 12 is spot-welded to the inner pipe 11, and a reduced diameter section 12b on the other side. Are fixed to the flange 13 by arc welding.

The reduced diameter portion 12b on the other side of the outer tube 12 of the inner tube 11
On the outer periphery of the portion corresponding to the above, the above-described metal thin wire cord c is cut into an appropriate length and wound around almost the entire periphery, and as shown in FIG. It is fixed and is in elastic contact with the inner periphery of the reduced diameter portion 12b of the outer tube 12.

The double exhaust pipe 10 of the present embodiment has the above-described configuration. When high-temperature exhaust gas flows through the inner pipe 11 as shown by an arrow, the inner pipe 11 becomes higher in temperature than the outer pipe 12. FIG.
As shown by the dashed line, the metal wire c is also moved outward.

Next, when the exhaust gas stops flowing due to the stop of the engine, the inner tube 11 is cooled and contracts, and the thin metal wire c returns to the position shown by the solid line in FIG.

Accordingly, when the operation and stop of the engine are repeated, the thin metal wire string c reciprocates while being rubbed against the inner surface of the reduced diameter portion 12b of the outer tube 12. Because it is welded
No peripheral swelling or hardening due to spot welding occurs on a flat surface serving as a sliding surface with the inner surface of the outer tube 12, and the sliding with the outer tube due to thermal deformation is performed smoothly.
1 is held elastically for a long time.

The thin metal wire string of the present invention can be applied to a cushioning material of a portion exposed to a high temperature in addition to the double exhaust pipe of the above embodiment, and is shown in FIGS. Various cross-sectional shapes can be selected according to the application as exemplified in D).

Further, the metal thin-wire cord of the present invention can be provided at a lower cost than a press-formed product by being cut into appropriate lengths so as to correspond to various shapes of mating parts. .

Further, as the fine metal wire string of the present invention, a fine metal wire obtained by knitting or weaving other than knitting can be used.

[Brief description of the drawings]

FIG. 1 is a perspective view of a manufacturing process of an embodiment of a thin metal wire string of the present invention.

FIG. 2 is a sectional view of an embodiment of the double exhaust pipe of the present invention.

FIG. 3 is an enlarged cross-sectional view of a state where the metal thin wire string is spot-welded to an inner pipe.

FIG. 4 is various cross-sectional views of the embodiment of the thin metal wire string of the present invention.

FIG. 5A is a perspective view showing a manufacturing process of a conventional cushion ring using a thin metal wire, and FIG. 5B is a perspective view of a completed product thereof.

[Explanation of symbols]

 a: heat-resistant thin metal wire c: thin metal wire d: recess 10: double exhaust pipe 11: inner pipe 12: outer pipe

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Claims (5)

[Claims] 1. A thin metal wire string formed by elongating and compressing a knitted or woven heat-resistant metal thin wire. 2. A thin metal wire cord according to claim 1, wherein said thin heat-resistant metal wire knitted in a tubular shape is elongated and compression-molded. 3. The thin metal wire cord according to claim 1, wherein the cord has a substantially concave cross section. 4. A double exhaust pipe having an inner pipe inserted into an outer pipe, one end of the outer pipe fixed to the inner pipe, and the other end of the outer pipe spaced from the inner pipe by a gap. In the cushion interposed in the gap, the metal thin wire string according to claim 1, 2 or 3 is cut into an appropriate length, wound around the outer circumference of the inner pipe, and welded to the gap to intervene in the gap. Features a double exhaust pipe cushion. 5. The double exhaust pipe cushion according to claim 4, wherein the welding is spot welding.