JPH0960730A - Spiral gasket and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the spiral gasket and its manufacture, which is inexpensive, and enables the centering of a gasket main body to be processed without using a ring and the like. SOLUTION: In the spiral gasket 1 which comprises a hoop member 2 piled up onto a filler member 3 wound in a spiral, the lower end part of one round winding portion 29 of the hoop member 2 at the innermost circumference, is bent to the center side by more than two third of its circumference in the circumferential direction, so that a centering part 4 is thereby formed. The terminal end part 2b of one round winding part 2 of the hoop member is fixed by spot welding. When the gasket 1 is mounted to the faucet part of an exhaust pipe, since a gasket main body is accurately centered by the centering part 4, the filler member 3 of the gasket 1 is prevented from being exposed to gas, and falling out can thereby be effectively prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape-shaped metal corrugated thin plate (hereinafter referred to as a hoop), which is used for a joint portion of high-temperature and high-pressure equipment and pipes, for the purpose of sealing fluids such as water, oil, steam and gas. And a tape-shaped filler such as asbestos or expansive graphite (hereinafter abbreviated as filler) in a state where they are superposed on each other and wound in a spiral shape multiple times, especially for automobiles. The present invention relates to an improved structure of a spiral wound gasket which is useful when used in a flange joint having a plug-in structure such as exhaust system parts.

[0002]

2. Description of the Related Art A spiral wound gasket is formed by sandwiching a tape-like metal hoop formed in advance in a substantially V-shape or a W-shape with a filler such as asbestos tape, and overlapping and winding each other. It is manufactured and is called the basic form. 6 to 7 show a conventional spiral gasket 1. In the figure, 2 is a thin metal plate having a corrugated cross section (thickness of about 0.13).
mm to 0.15 mm), and 3 is a filler material formed mainly of inorganic fibers or the like.

In order to manufacture the spiral gasket having the above structure, first, only the hoop material 2 is wound up (not shown).
1 to 3 turns (idling), forming a welded fixed portion by spot welding at a required portion of the idling part, and then inserting the filler material 3 and wrapping the hoop material and the filler material in layers, At the end, only the hoop material is wrapped and spot-welded to fix the hoop materials together.

Then, the welding fixing portion 2b of the inner hoop member
In manufacturing, the hoop material portion 2a is left at about 1/4 turn away from the beginning of winding, and the hoop material part 2a that touches the 1/4 turn is left, but since burr at the end is dangerous during handling, The hoop material portion 2a is cut and removed in the vicinity of the welding fixing portion 2b to obtain a product.

In addition, for the purpose of preventing deformation and centering of the gasket main body due to tightening pressure, metal reinforcing rings are attached to the inside and / or outside of the gasket main body with inner ring, outer ring and inner / outer ring. Various types referred to as "etc." are known. The spiral wound gasket has a structure in which a metal hoop and a filler with cushioning property are wound alternately on top of each other, and is highly resilient. And is considered one of the ideal gaskets for high temperatures. And it was widely known as a gasket used for a joint of an exhaust system component such as an exhaust manifold of an automobile, a front tube, and a muffler.

As a type of filler, conventionally, asbestos tape obtained by slitting asbestos paper into strips was generally used, but asbestos fiber is a natural mineral, and it is assumed that it is caused by asbestos fiber due to concern about resource depletion. Since the current health problems have become a social problem and the use of asbestos has been restricted worldwide, non-asbestos paper mainly made of inorganic fibers other than asbestos is slit (hereinafter N
A tape).

As a material used for this NA tape, various inorganic fibers (other than asbestos) and needle-like or scale-like fillers are combined and fixed with a binder, but the fiber diameter is thin and fibril-like. Compared with the asbestos fiber, which has a large diameter, many of them are thick and rigid, and there is no entanglement between the inorganic materials. Therefore, when the spiral wound gasket using the NA tape as a filler is directly exposed to a high-temperature gas and the binder in the NA tape is decomposed, there is a problem that the filler is easily dropped off due to vibration or the like. Was.

[0008]

Generally, as shown in FIG. 5, an upstream side flange 9 into which exhaust gas flows in order to improve operability when joining flanges to a joint portion of exhaust system parts for automobiles. To project into the downstream side flange 10 to form a spigot portion 11, which is then attached to the downstream side flange 1.
There is a structure in which 0 is welded into the exhaust pipe, and the spiral wound gasket 1 is fitted in the spigot portion 11 and seals between the upstream side and downstream side flanges 9 and 10. At this time, the size of the gasket 1 is made larger than the outer diameter of the spigot portion 11 and smaller than the inner diameter of the flange portion 10 in order to improve the operability when loading the spigot portion 11 and joining the flanges. Therefore, FIG.
As shown in (3), the center of the exhaust pipe 12 and the center of the gasket may deviate, and the filler material 3 of the gasket 1 may be attached so as to be directly exposed to the exhaust gas. In such a case, when using conventional asbestos tape as a filler, it did not cause a big problem,
Since the NA tape has a weak bonding force between the inorganic materials, when the binder is thermally decomposed, it is easily dropped due to vibration or the like, and the sealing performance of the gasket 1 is deteriorated within a short period of time.

As a countermeasure against this, it is conceivable to use a metal reinforcing ring with an inner ring attached to the inside of the gasket main body. However, since the weight of the entire gasket increases, it goes against weight reduction or punching or cutting out. There is a problem that the price becomes high because the metal ring is used.

As another method, there is known a technique (in Japanese Utility Model Publication No. 3-93654) in which an annular body for centering is integrally provided on the inner peripheral side of a spiral wound gasket body. When mounting after forming the main body, the number of steps is increased and the work is complicated, and when continuously manufacturing the annular body assuming that the shape of the hoop of the main body is deformed, two types of rolls for bending the hoop are required. From
Both of these have contributed to cost increases.

As another technique, there is also one in which a polygonal guide is attached to the inside or outside of the gasket body (Japanese Patent Laid-Open No. 4-73470), which also cuts the roll for bending the hoop and both sides. Since two types of rolls are required and an auxiliary winding core is required between the polygonal body and the main body, an increase in cost is inevitable.

An object of the present invention is to solve the above-mentioned problems, and to provide a spiral wound gasket and a method for manufacturing the same, which can center the gasket body at low cost without using a ring or the like. It is in.

[0013]

In order to achieve the above object, a spiral wound gasket according to the invention of claim 1 is formed into a spiral winding by superposing a hoop material and a filler material of a tape-shaped corrugated thin metal plate. In a spiral wound gasket formed by winding, the upper end or the lower end of any inner circumference hoop material from the innermost circumference of the gasket to the filler material is centered by a predetermined length in the circumferential direction. The gist of the present invention is to have a centering portion that is bent in the direction of.

According to a second aspect of the present invention, in the spiral wound gasket according to the first aspect of the present invention, the centering portion is bent on the innermost hoop member and is ⅔ or more in the circumferential direction. Is the gist.

Further, in the method for manufacturing a spiral wound gasket according to the third aspect of the present invention, after a tape-shaped thin metal plate is processed into a predetermined shape in a winding die having a groove on one surface so that the cross section becomes L-shaped, The hoop material obtained by setting the hoop material is set by bending with a presser piece having a shape symmetrical with the winding form at the position of the groove so as to bend toward the center of the lower end of the thin metal plate.
After winding around, the end portion is welded, and then the pressing piece is lowered, and then, while being pressed by another pressing piece, the hoop material at the innermost circumference is wound a predetermined number of times, and then the filler material. The gist of the invention is to manufacture a spiral wound gasket by superposing them on top of each other and winding them a predetermined number of times, and only the outermost hoop material is idled once and welded.

According to the present invention, the upper or lower end of the inner hoop member of the gasket body is bent inward to form the centering portion, and the centering portion is circumscribed on the spigot portion of the exhaust pipe. The gasket body does not protrude inside the pipe, centering is easily possible, and the filler material does not come into contact with the exhaust gas, so it can be prevented from falling off and the sealing performance can be maintained for a long period of time.
Further, when the inner hoop member is bent inward, for example, a pressing piece may be pressed against a winding die having a groove to form the inner hoop material. Since it does not change, cost increase can be prevented.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION As an embodiment of the invention of claims 1 and 2, as shown in FIGS. 1 and 2, a hoop material 2 and a filler material 3 made of a tape-shaped metal corrugated thin plate are superposed on each other. The spiral wound gasket 1 is configured, and, for example, the lower end portion of the one-turn winding portion 2a of the innermost hoop material is bent toward the center by 2/3 or more in the circumferential direction to form the centering portion 4. The end portion 2b of the hoop material portion of the one-turn winding portion 2a that is formed is spot-welded.

An embodiment of the invention of claim 3 is claim 1
As a method for manufacturing the spiral wound gasket, for example, as shown in FIG.
The method of is proposed. In the figure, after the tape-shaped thin metal plate 2 is processed into a predetermined shape on the winding die 6 having a groove 6a on one surface so that the cross section becomes L-shaped, it is set as shown in the figure,
After pressing the obtained hoop material 2 one round while bending the lower end of the metal thin plate 2 toward the center by applying pressure at the position of the groove 6a with the pressing piece 7 having a shape symmetrical with the winding die 6. The end portion 2b is spot-welded. Then, after lowering the presser piece 7, while applying pressure by another presser piece 8, the hoop material 2 on the innermost circumference is vacantly wound a predetermined number of times, and then the filler material 3 is sandwiched therebetween and wound a predetermined number of times. , Only the outermost hoop material is 1
Wind it around and spot weld its end.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below.
1 and 2 show an embodiment of a spiral wound gasket 1 according to the present invention. In the figure, a spiral wound gasket 1 is formed by spirally winding a hoop material 2 of a tape-shaped metal corrugated thin plate and a filler material 3 of an NA tape mainly composed of an inorganic fiber. However, the inner peripheral portion and the outer peripheral portion thereof are empty winding portions 5a and 5b made of only the hoop material 2. At least the innermost peripheral portion of the inner peripheral air-wound portion 5a is bent at the lower end portion of the one-winding portion 2a of the hoop material to the center side in the circumferential direction by ⅔ or more to form the centering portion 4 and the end portion 2b thereof. Is spot welded. The length of the centering portion 4 needs to be bent in the circumferential direction by ⅔ or more of one round of the hoop material, but if it is more than that, there is no problem and it is not limited to the innermost circumference. There is no problem even if the hoop material after the second round of the empty winding portion 5a is bent and formed. Further, the width of the centering portion 4 varies depending on the exhaust pipe used, but it is sufficient if it is about 1 to 3 mm. The bending position can be appropriately determined according to the length. Filler material 3
As the type, the NA tape or the expanded graphite tape is effective, but from the viewpoint of cost, the NA tape is preferable, and the type and shape of the hoop material 2 are not limited.

FIG. 3 shows an outline of an embodiment of a method for manufacturing a spiral wound gasket according to the present invention. In the figure, 6 is a winding die having a single-sided groove 6a having an L-shaped cross section, and 7 is a rotatable pressing piece symmetrical with the winding die, which engages with and disengages from the winding die 6. It is possible.

First, a tape-shaped metal (for example, SUS30
4) After drawing the thin plate into a substantially W shape, the obtained hoop material 2 is set on the winding form 6 as shown in the figure, and the winding form 6 is rotated and the pressing piece 7 is brought closer to engage with it. Pressure is applied at a position facing the groove 6a to bend the lower end of the innermost circumference 2a of the hoop material 2 toward the center to form the centering portion 4, and the hoop material 2 is wound around once and then the end portion thereof is wound. Spot weld. After that, the presser piece 7 is lowered to be released, and then the presser piece 8 is engaged and pressure is applied to rotate the winding form 6 to continuously turn on the hoop material 2 wound one round, and then the hoop material 2 for two turns. After only idling the inner circumference to make the inner part idling portion 5a,
Place the NA tape filler material on top of each other 5
It is wound around, and then only the hoop material 2 is wound around once again, and the end portion of the hoop material 2 is spot-welded to form the outer circumference empty-wound portion 5b and completed.

The spiral wound gasket 1 of the present invention constructed as described above is used by being fitted in the spigot portion 11 of the exhaust pipe 12 as shown in FIG. Therefore, both end surfaces in the width direction of the gasket 1 are surely brought into contact with the facing surfaces of the upstream side flange 10 and the downstream side flange 9, and the filler material 3 is not directly exposed to the exhaust gas, so that the filler material 3 does not drop off for a long period of time. A high sealing property can be maintained.

[0023]

As is apparent from the above description, the spiral wound gasket according to the present invention is provided with the centering portion formed by bending the upper end portion or the lower end portion of the inner peripheral hoop member of the gasket body to provide the gasket Since it is possible to prevent the filler material of the gasket body from squeezing out inward of the pipe without impairing the attachability, it is possible to avoid the gasket body from falling off and to secure the initial sealability for a long period of time. Moreover, according to the manufacturing method of the present invention, since the centering portion can be molded only by pressing the pressing piece having a symmetrical shape with the groove of the winding die, the winding die and the pressing piece of the conventional device are slightly improved. Good. Further, the welding to the filler material may be performed at one place after winding the hoop material once, and the productivity is good.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of one embodiment of the present invention.

FIG. 3 is a schematic view showing a main part of an apparatus for manufacturing an embodiment of the present invention.

FIG. 4 is a cross-sectional view of an example of a usage state of the embodiment of the present invention.

FIG. 5 is a transverse cross-sectional view of an example of a usage state of a conventional spiral wound gasket.

FIG. 6 is a plan view showing a conventional spiral wound gasket.

7 is a cross-sectional view of FIG.

[Explanation of symbols]

 1 spiral wound gasket 2 hoop material 2a innermost wound portion of hoop material 2b innermost end welded portion of hoop material 2 filler material 4 protrusion 5a inner air wound portion 5b outer air wound portion 6 winding type 6a Groove 7 Presser piece 8 Presser piece 9 Upstream flange 10 Downstream flange 11 Inlay part 12 Exhaust pipe

[Procedure amendment]

[Submission date] February 9, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

[Fig. 3]

[Procedure amendment]

[Submission date] February 23, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

[Fig. 2]

Claims (3)

[Claims] 1. A spiral wound gasket formed by superposing a hoop material of a tape-shaped corrugated thin metal plate and a filler material and winding the spiral material into a spiral shape, wherein the hoop material at the innermost circumference of the gasket is filled with the filler. A spiral wound gasket, characterized in that an upper end portion or a lower end portion of any inner peripheral hoop material reaching the material has a centering portion which is bent toward the center side by a predetermined length in the circumferential direction. 2. The spiral wound gasket according to claim 1, wherein the centering portion is formed by bending the innermost hoop member by 2/3 or more in the circumferential direction. 3. A tape-shaped thin metal plate is processed into a predetermined shape on a winding die having a groove formed on one side so that its cross section becomes L-shaped, and then set, and a pressing piece having a shape symmetrical with the winding die is used. While applying pressure at the position of the groove and bending the lower end portion of the thin metal plate toward the center, the obtained hoop material is wound around once and then the end portion thereof is welded, and then the pressing piece is pressed. , And then apply pressure with another presser piece to the above-mentioned innermost hoop material for a predetermined number of times, then lay them on top of each other with the filler material sandwiched between them and then wrap them a predetermined number of times to obtain the outermost hoop material. A method for manufacturing a spiral wound gasket, characterized in that the spiral wound gasket is manufactured by winding the only one piece around and welding it.