JPH0510449A - Gasket and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a gasket excellent in strength, heat resistance, flexibility and sealing performance by forming the gasket of graphite and fine diameter metal wire. CONSTITUTION:Graphite 2 formed into ring shape is covered, from the inner and outer peripheral surface to the upper and lower end faces, with a knitted net body 3 made of a run of fine diameter metal wire 3a. The fine diameter metal wire 3a of this net body 3 is partially embedded into the molded graphite 2, and the inner and outer peripheral wall parts of the graphite 2 is filled into the compressed meshes of the knitted net body 3 so as to form the inner and outer peripheral surface into smooth surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket having excellent heat resistance, flexibility and sealing properties, and a method for producing the gasket.

[0002]

2. Description of the Related Art Conventionally, as a gasket for sealing a portion where a high temperature fluid is generated, such as a muffler of an automobile, graphite has been used as a main composition because of its extremely small coefficient of thermal expansion and excellent heat resistance. A molded body is used.
Then, in order to obtain the moldability, a plurality of thin-walled graphite molded pieces and a plurality of metal mesh bodies are superposed on each other so that the graphite molded pieces are arranged at least on the inner and outer peripheral surface sides to form an annular material. A method of manufacturing a gasket having a desired shape by compressing the material has also been developed.

[0003]

However, in such a structure, since the plurality of metal mesh bodies are independent from each other and graphite is compression-filled in the meshes thereof, There is a problem that the metal mesh body and the graphite layer tend to be easily separated at the interface due to vibration during handling or use, resulting in poor moldability and inability to obtain a long-term sealing effect. There is. Further, during molding, graphite adheres to the inner surface of the mold and is inferior in mold releasability, so that a mold release agent is required and the production efficiency decreases. An object of the present invention is to provide a gasket that can solve such problems and a method for manufacturing the gasket.

[0004]

In order to achieve the above object, the gasket of the present invention is a ring-shaped gasket, in which the inner and outer peripheral surfaces enclosing the molded graphite and the upper and lower end surfaces have a small diameter. A structure in which a mesh made of a metal wire is formed of a compressed knitted mesh body, a part of the compressed mesh body is embedded in graphite, and the graphite is filled in the meshes on the inner and outer peripheral surfaces of the compressed mesh body. Is to have.

As a method of manufacturing the above gasket,
Graphite formed in a thin plate shape is housed in a flat tubular net body having a constant width formed by knitting thin metal wires, and the flat tubular net body is bent into an annular shape to form a material. An annular material is inserted into a female mold, and compression molding is performed by a male mold in a direction in which the upper and lower open ends of the annular material contract, and the compression causes the inside and outside of the flat tubular net body to be partially inside graphite. And is filled with graphite in the stitches on the inner and outer peripheral surfaces of the tubular mesh body to form a ring having a desired thickness and height.

[0006]

[Function] The entire surface of the ring-shaped compression-molded graphite, from the outer peripheral surface to the inner peripheral surface through the upper and lower end surfaces, is covered with a knitted tubular mesh body of continuous thin metal wires. Therefore, there is no possibility that the molded graphite and the tubular net body are separated from each other, and both have a completely integrally molded structure so that the shape is not lost and the moldability is good, and at the time of production. The thin metal wire forming the inner and outer peripheral surfaces improves the mold releasability and improves the production efficiency.

Further, since a part of the thin metal wire forming the tubular mesh body is embedded in the graphite while being entangled in the graphite during molding, the graphite is retained and partial peeling is prevented. At the same time, graphite is densely packed in the mesh of the cylindrical net exposed on the inner and outer peripheral surfaces,
Strength and surface smoothness are improved, and uniform softness and flexibility are maintained over the whole by a series of thin metal wires, excellent adhesion at joint parts etc. and good sealing effect Demonstrate.

[0008]

Embodiments of the present invention will now be described with reference to the drawings, in which 1 is a ring-shaped member having a desired wall thickness and height formed from a composite of graphite 2 and a knitted metal mesh body 3 that has been compressed and deformed. With the gasket formed in the above, the inner and outer peripheral surfaces and the upper and lower end surfaces of the ring-shaped molded graphite 2 are covered with a series of continuous thin metal wires 3a forming the above-mentioned knitted metal net body 3. While being formed, the mesh 4 of the metal mesh body 3 is filled with graphite 2 and the thin metal wire 3a is press-fitted into the inner and outer peripheral surfaces of the molded graphite 2 in a state of being bitten. The inner and outer peripheral surfaces and the upper and lower end surfaces are formed into smooth surfaces by the metal mesh body 3 and the graphite 2 filling the stitches 4.

Further, the graphite 2 and the metal net body 3 are compressed at the time of forming the gasket, and the graphite 2 is filled in the stitches 4 of the metal net body 3 which is compressed and deformed as described above.
The thin metal wire 3a of the metal mesh body 3 is embedded in the molded graphite 2 in a state of being entangled by being entangled by the compression deformation.

To manufacture such a gasket 1,
As shown in FIG. 3, first, a strip-shaped flat tubular net body 13 having a constant width and an appropriate length is knitted by the thin metal wire 3a, and the flat tubular net body 13 is formed into a thin plate shape. The formed band-shaped graphite molded body 12 is stored.

Next, the flat cylindrical net body 13 accommodating the band-shaped graphite molded body 12 is obliquely cut and divided into fixed lengths, and the divided flat cylindrical net body 13 is divided as shown in FIG. Is bent in an annular shape so that the slanted cut end surfaces 13a and 13b of the slanted cut end surfaces 13a and 13b are in contact with each other to form a material 11. As shown in FIG. The open end portions, which are continuous over the peripheral surface, are housed in the female mold 5 in a state of being oriented in the vertical direction. At this time, in order that the annular material 11 can be easily housed in the female die 5, both ends of the inclined cutting are housed in a state of being overlapped with each other.

The female die 5 has a ring-shaped molding groove portion 6 having a predetermined depth having the same groove width as the thickness of the gasket 1 to be molded.
Is formed, and the annular material 11 is formed in the molding groove portion 6.
Then, the material 11 expands due to the elastic restoring force of the thin metal wire 3a forming the tubular mesh body 13 and the outer peripheral surface thereof is pressed against the outer inner wall surface 6a of the forming groove portion 6. In this state, the opposite end portions 13a, which are the inclined cut end surfaces of the material 11,
13b is cut in advance so that the flat tubular net body 13 forming the material 11 has a cutting length substantially equal to the inner circumferential length of the outer inner wall surface 6a of the forming groove portion 6 so as to be joined to each other in a butt state. Keep it.

Next, as shown in FIG. 6, the annular material 11 housed in the molding groove portion 6 of the female die 5 is provided with a ring-shaped pressing die portion 8 which can be slidably inserted into the molding groove portion 6 as shown in FIG. Gasket 1
Is molded. In the outer peripheral portion of the inner bottom surface of the molding groove portion 6 of the female die 5, an inclined surface 9 is formed so as to extend from the inner bottom surface to the lower end of the outer inner peripheral wall.

The molding state of the gasket 1 will be described below.
The ring-shaped pressing part 8 of the male mold 7 is inserted into the molding groove 6 of the female mold 5 and the lower end pressing plane 8a is further moved downward from the state of being brought into contact with the upper end edge of the annular material 11, When pressed under pressure, the annular material 11 is compressed so as to buckle, and in the initial stage of compression, the flat tubular net body 13 enclosing the graphite compact 12 opens in the inner and outer peripheral directions. Then, the inner peripheral surface side is pressed against the inner inner wall surface 6b of the molding groove 6 while the outer peripheral surface is pressed against the outer inner wall surface 6a of the molding groove 6 of the female die 5.

Further, as the internal graphite molded body 12 undergoes buckling deformation and the downward movement of the male die 7 progresses, the upper and lower thin metal wires 3a forming the stitches 4 of the flat cylindrical net body 13 are The stitches 4 are pressed in a direction in which they overlap with each other and the stitches 4 are compressed and deformed in the shape of a horizontally elongated slit. The small-diameter metal wires 3a, 3a project from both ends, and are superposed or entangled with each other.

In the meantime, the compressed and buckled portions of the graphite compact 12 are overlapped while being regulated by the opposing inner wall surfaces 6a and 6b of the molding groove 6 of the female die 5 to form a laminated state to increase the wall thickness. . On the other hand, the inner and outer peripheral surfaces of the flat tubular net body 13 are also regulated by the opposing inner wall surfaces 6a and 6b of the molding groove portion 6, and a part thereof is inward as the male die 7 moves downward, that is, a graphite molded body.
12 is bent and deformed, and the thin metal wire 3a of the portion is press-fitted and embedded in the graphite, and the graphite molded body 12 is compressed to a thick wall 12
The slits 4 of the flat tubular net body 13 whose inner and outer peripheral portions are in contact with the facing inner wall surfaces 6a and 6b of the forming groove portion 4 are compressed into the slits.
It is pushed in from the inside and filled.

When the pressing by the male die 7 is completed, the thin metal wire 3a is formed in close contact with the facing inner wall surfaces 6a and 6b of the molding groove 6 and the thin metal wire 3a. The smooth inner and outer peripheral surfaces of the gasket 1 are formed by the compressed and deformed graphite filling in the stitch 4, and the presence of the thin metal wire 3a allows the gasket 1 to be easily separated from the mold.

As described above, the ring-shaped gasket of the present invention is formed of a knitted compression mesh body made of a thin metal wire whose inner and outer peripheral surfaces and upper and lower end surfaces of graphite molded in a ring shape are continuous.
Since a part of this compression net is embedded in graphite and the graphite is filled in the stitches on the inner and outer peripheral surfaces of the compression net, the outer periphery of the ring-shaped compression molded graphite Since the entire surface from the surface to the inner peripheral surface through the upper and lower end surfaces is covered with a knitting compression mesh body of a series of thin metal wires, the molded graphite and the mesh body are completely separated from each other. There is no fear, the two have a completely integrally molded structure, exhibit extremely excellent moldability without deformation, and the graphite powder does not peel off during handling or use.

Further, since the stitches of the compression net body forming the inner and outer peripheral surfaces and the upper and lower end surfaces of the gasket are densely filled with graphite, the strength and the surface smoothness are improved. With a series of small-diameter metal wires, it is possible to maintain uniform flexibility and flexibility throughout the whole, excellent adhesion at the joint part, etc., and a good sealing effect. In addition, graphite exhibits excellent heat resistance.

Further, as a method of manufacturing such a gasket, graphite formed in a thin plate shape is housed in a flat tubular mesh body having a constant width formed by knitting thin metal wires, and the flat tubular shape is formed. A material is formed by bending the net body into an annular shape, and the annular material is inserted into a female mold and compression-molded by a male mold in a direction in which the upper and lower open ends of the annular material contract. By compressing, the inside and outside of the flat tubular net body is partially embedded in graphite, and graphite is filled in the stitches of the inner and outer peripheral surfaces of the tubular net body to form a ring shape having a desired wall thickness and height. Since it is a material, the material consists of a flat tubular net body containing thin plate graphite, so it is easy to handle and can be smoothly and accurately supplied into the female mold, and compression molding is performed in that state Since it is a product, it can be molded efficiently and is suitable for mass production. It is intended.

Further, at the time of its production, the annular material is compressed to partially embed the thin metal wire on the inner and outer peripheral surfaces of the flat tubular net body in the graphite, and the graphite is put inside and outside the tubular net body. Since it is filled in the stitches on the peripheral surface, the thin metal wires of graphite and the flat tubular mesh and the thin metal wires are intertwined with each other, resulting in uniform strength, heat resistance, and flexibility. It is possible to obtain a gasket having adhesiveness.

[Brief description of drawings]

FIG. 1 is a simplified perspective view of a gasket,

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 3 is a simplified perspective view of a strip-shaped flat tubular net body;

FIG. 4 is a simplified perspective view of the annular material during the manufacturing process,

FIG. 5 is a simplified vertical cross-sectional view of a mold containing materials.

FIG. 6 is a simplified vertical sectional view showing a molded state.

[Explanation of symbols]

1 gasket 2 graphite 3 metal mesh 3a thin metal wire 4th stitch 5 Female mold 6 forming groove 7 Male mold 8 Ring-shaped stamping part 11 annular material 12 Strip-shaped graphite compact 13 Flat tubular mesh

Claims (2)

[Claims] 1. A ring-shaped gasket, wherein the inner and outer peripheral surfaces enclosing molded graphite and the upper and lower end surfaces are formed of a knitted mesh body in which stitches of continuous thin metal wires are compressed. A gasket, wherein a part of the compression net body is embedded in graphite and the graphite is filled in the stitches on the inner and outer peripheral surfaces of the compression net body. 2. A flat tubular net body having a constant width formed by knitting small-diameter metal wires, containing graphite formed in a thin plate shape, and bending the flat tubular net body into an annular shape. The annular material is inserted into a female mold and compression molded by a male mold in a direction in which the upper and lower open ends of the annular material contract, and the compression causes the inside and outside of the flat tubular net body to be compressed. A method for producing a gasket, which comprises partially embedding graphite and filling graphite in the stitches on the inner and outer peripheral surfaces of the tubular net body to form a ring having a desired thickness and height.