JPH0369865A - Manufacture of seal body - Google Patents

Abstract

PURPOSE:To enhance the working ability of manufacturing a seal body by forming a plurality of recesses on one surface of a band-like expansible graphite sheet by use of a knurling process, by winding a band like slide surface material coated thereover with a lubricant, around the outer peripheral surface of a cylindrical body of the graphite sheet superposed therewith a metal gauze and a heat-resistnat sheet, and by press-molding the cylindrical body. CONSTITUTION:One surface of a band like expansible graphite sheet 2 is knurled so as to form recessed 5, and further, is coated with lubricant which therefore filled in the recesses 5 so as to form a slide layer 6 having a slide surface. Meanwhile, a metal gauze 8 and a heat-resistant sheet 9 are superposed with each other so as to form a cylindrical body 10 around which the slide layer 6 is wound. Then, it is fitted on a die core 13, and is compressed axially so as to obtain a predetermined shape. Since a spherical surface body is thus formed, the work of the manufacture thereof can be facilitated, and with the use of the lubricant, it is possible to prevent both members from being shifted toward each other and to reduce the difference between a static frictional coeffi cient and a dynamic frictional coefficient.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a seal body such as a spherical seal body used, for example, in an exhaust pipe joint of an automobile.

[Conventional technology]

Conventionally, the spherical seal bodies used in exhaust pipe joints are:
For example, the spherical seal body disclosed in JP-A-54-76759 (hereinafter referred to as "Prior Art I") has heat resistance and is compatible with the mating material. Although it has the advantage of being highly durable and has significantly improved impact strength, it also has the disadvantage of often generating abnormal noise when sliding under dry friction conditions. The difference between the static friction coefficient and the kinetic friction coefficient of the heat-resistant material (expanded graphite, etc.) that constitutes the seal body is large, and the frictional resistance of the seal body made of this heat-resistant material against the sliding speed is negative resistance (
In other words, this is thought to be due to the fact that as the sliding speed increases, the friction coefficient decreases (resistance).

Therefore, the present applicant first filed Japanese Patent Application No. 57-193395 (
In JP-A No. 59-83830) (hereinafter referred to as "prior art (1)"), a sliding member (sealing material) suitable for use in an exhaust pipe joint was proposed which solved the drawbacks of the above-mentioned prior art (2).

In other words, prior art (2) uses a reinforcing material made of a wire mesh obtained by weaving or knitting thin metal wires, and a large number of small holes are made in the thickness direction, and these small holes are also filled on the surface. This seal body is formed by molding together a sheet-like heat-resistant material coated with a lubricant made of polytetrafluoroethylene resin to the thickness, and the lubricant is adhered to the surface.

The lubricant deposited on the surface of this seal body has effects such as reducing the coefficient of friction, preventing the heat-resistant material that makes up the base material from adhering to the mating material, and reducing the difference between the coefficient of static friction and the coefficient of dynamic friction. In addition, the lubricant exhibits no negative frictional resistance with respect to the sliding speed, so in conjunction with the above-mentioned effects, it suppresses the occurrence of self-excited vibrations due to "adhesion-sliding" and reduces abnormal noise. This was effective in contributing to prevention of occurrence.

[Problem that the invention seeks to solve]

The seal body made of the prior art (1) described above solves the drawbacks of the prior art (2) in terms of performance. Komei discovered a manufacturing flaw in the process.

That is, as shown in FIG. 14, Komei's process involves fixing a tool equipped with a plurality of needle-shaped bodies a with diameters of 0.3 to 1.5 mm to the upper mold of the press (not shown), and A method was adopted in which a plurality of small holes C were formed by pressing (blessing) the shaped body a onto a sheet-like heat-resistant material (such as expanded graphite) b in the direction of the sheet plate surface, but in this method, the needle-like body a When the material penetrates the sheet-like heat-resistant material, a paris (
The burr d is produced (Fig. 15), and the manufacturing process is complicated in that the hole formed by the needle a requires a step of crushing the burr d by pressing again after processing.

The present invention aims to obtain a method for manufacturing a seal body such as a seal body for an exhaust pipe joint, which can take advantage of the performance advantages of the prior art H described above, eliminate complexity in manufacturing, and improve workability. The purpose is to

[Means for solving problems]

The present invention adopts the following configuration (technical means) in order to achieve the above-mentioned object.

In other words, one surface of an expanded graphite sheet is knurled to form a plurality of recesses on the surface, and a lubricant is applied to a predetermined thickness so as to fill these recesses, forming a slip layer. The face material is formed by overlapping a reinforcing material made of wire mesh and a heat-resistant sheet material and winding them into a cylindrical shape.Then, the surface material is wrapped around the outer peripheral surface of a cylindrical body, with the sliding layer on the outside, and then the desired shape and dimensions are formed. This is a method of manufacturing a seal body, which comprises fitting the seal body into the outer circumferential surface of a core of a mold having the seal body and compression molding the seal body in the axial direction.

In the above-mentioned manufacturing method, one surface of an expanded graphite sheet is knurled to form a plurality of recesses on the surface as a sliding surface material, and the surface is filled with a predetermined thickness so as to fill these recesses. After applying a lubricant to form a sliding layer, this is inserted into a bag-shaped wire mesh and compressed in the direction of the sheet surface, or a wire mesh is placed on the surface of the sliding layer and the sheet is It is possible to use one that is compressed in the direction of the plate surface and integrated with a wire mesh.

When this sliding surface material is used, a sliding layer in which the lubricant and wire mesh are exposed is formed on the surface of the outer convex spherical surface of the seal body.

Another manufacturing method involves knurling the surface of one end of a long expanded graphite sheet over a predetermined length to form a plurality of recesses on the surface. A sliding surface material is formed by applying a lubricant to a predetermined thickness so as to fill the sheet with a sliding layer on a part of the surface of the sheet,
A cylindrical body is formed by overlaying a reinforcing material made of wire mesh and winding it so that the sliding layer is located on the outermost periphery, and this is inserted into the outer periphery of a core of a mold having the desired shape and dimensions to form a shaft. This is a method for manufacturing a seal body, which comprises compression molding in the direction.

Here, each component in the above-mentioned configuration (manufacturing method) will be specifically explained based on the drawings. Films with a thickness of 0.3 to 1.0 mm, which are commercially available from Nippon Carbon Co., Ltd. under the name "Oil" and "Nika Film" from Nippon Carbon Co., Ltd., respectively, are suitable.

Next, a pressure roller 3 is provided with a plurality of regular protrusions 3L of varying heights on its outer peripheral surface, and a guide roller 4 is arranged in series with the pressure roller 3 while maintaining a predetermined gap S. The expanded graphite sheet 2 is supplied into the gap of the knurling tool N, and the sheet 2 is subjected to the knurling process by being passed through, and a plurality of independent recesses 5 are formed on the surface of the sheet 2.
(Figs. 1 to 3).

The shape of the recess 5 formed on the surface of the expanded graphite sheet 20, in other words, the protrusion 3 formed on the outer peripheral surface of the pressure roller 3.
As the shape of 1, a cylindrical part and a conical part at the tip of the cylindrical part, a square prism part and a square pyramid part at the tip of the square prism part, a triangular pyramid, etc. are used as appropriate.

The height of this protrusion 3I is 1/2 to 2/3 of the thickness of the expanded graphite sheet 2 used, and the diameter is 0.5 to 1.5 mm (square prism, triangular pyramid). In this case, the length of one piece is preferably 0.5 to 1.0 mm), and the recesses 5 formed by these protrusions 31 are formed on the sheet surface at intervals of 1 to 3 mm, and the openings of the recesses 5 are formed on the sheet surface. The total area is 5 to 50% of the surface area.

Polytetrafluoroethylene resin (hereinafter referred to as PTFEJ) is applied as a lubricant to the surface of the expanded graphite sheet 2 with a plurality of recesses 5 formed on one surface so as to fill the recesses 5 as well. and P on the surface of the sheet.
A slip N6 made of TFE is formed (FIG. 4).

As the PTFE forming this slip N6, a PTFE dispersion (solid content 60% by weight) commercially available from Mitsui Fluorochemical Company under the name "Teflon 30J" is used.

This PTFE dispersion is (1) sprayed onto the surface of the expanded graphite sheet 20 in which the plurality of recesses 5 are formed. In this case, the PTFE is also filled in the recesses formed in the expanded graphite sheet 2, and after application, the solvent is completely volatilized by heating at 120°C for several minutes, and this treatment prevents the PTFE from peeling off by normal treatment. A slip N6 made of PTFE is formed in close contact with the surface of the expanded graphite sheet 2 to a certain degree.

This slip P! A solid lubricating filler such as graphite, molybdenum disulfide, tungsten disulfide, boron nitride, etc. can also be mixed with the PTFE forming i6 in a proportion of 50% by weight or less.

In addition to the above-mentioned sliding surface material 1, a sliding surface material 1' having a similar structure may also be used.

That is, the sliding surface material 1' has PTFE on the above-mentioned surface.
An expanded graphite sheet 2 having a slip N6 consisting of a metal wire is inserted into a bag-shaped wire mesh 7 formed by knitting thin metal wires into a bag shape and pressed in the direction of the plate surface of the sheet (FIG. 5); A belt-like wire mesh 8 formed by knitting or weaving fine wires is placed on the surface slip N6 of the expanded graphite sheet 2 and pressed in the direction of the plate surface of the sheet (FIG. 6), so that the expanded graphite sheet 2 and It is integrated with wire mesh 7.8.

This sliding surface material l' has a sliding layer on the surface of which PTFE and wire mesh are exposed.

Here, 1 gold! ! The thin metal wires that make up 7.8 are as follows:
Austenitic stainless steel (JIS-
5US304.316), ferritic stainless steel (J15-5IJS430), iron wire or galvanized iron wire (JS-G-3532), etc. Copper-based materials include copper-nickel alloy (cupronickel), copper-nickel-zinc alloy (nickel silver), brass, beryllium steel, etc., and other aluminum alloys can also be used.

The diameter of these thin metal wires is preferably 0.1 to 0.51, and the mesh size of the wire mesh made of these thin metal wires is approximately 3 to 6 m.
m is appropriate.

<Cylindrical body> The heat-resistant sheet material 9 made of an expanded graphite sheet prepared separately and the metal band w48 as a reinforcing material made of the thin metal wire are overlapped and wound into a cylindrical shape to form the cylindrical body 10 (No. Figure 7).

In forming this cylindrical body 10, as the heat-resistant sheet material 9, mica paper bonded with silicone resin, chrysotile or amosite-based asbestos paper or sheet, etc. can be used instead of the expanded graphite sheet.

<Compression molding> The above-mentioned sliding surface material 1 or 1' is placed on the outer peripheral surface of the cylindrical body 10 so that the PTFE sliding layer 6 of the sliding surface material or the sliding layer with exposed PTFE and wire mesh is located on the outside. (Fig. 8), and is inserted into the outer peripheral surface of the core 13 of a mold 12 having a partially concave spherical portion 11 on the inner surface, and in the mold 12, a molding pressure of 1 to 3 tons/Cd is applied in the axial direction. (Figure 9).

By this compression molding, a circular hole 14 is formed on the inner surface, a partially convex spherical surface section 15 is formed on the outer surface, and the surface of the convex spherical surface section 15 is made of PTF.
A spherical seal body 16 is obtained in which a sliding layer 6 made of E or a sliding layer in which PTFE and wire mesh are exposed is formed.

Next, a method different from the above-mentioned manufacturing method will be explained.

A predetermined length (
The knurling process is performed over a length corresponding to the outermost circumference l of the cylindrical body, and the sheet surface is knurled so as to fill a plurality of independent recesses 5 on one end surface of the sheet 2. PTFE is applied to the processed part, and a slipping layer 6 made of PTFE is applied to a part of the sheet.
This is used as the sliding surface material 1 which also serves as the heat-resistant sheet material 9 in the manufacturing method described above (FIG. 12).

This sliding surface material 1 and a reinforcing material consisting of a band-shaped wire mesh 8 formed by weaving or knitting the metal thin wires are overlapped, and a cylindrical shape is formed so that the sliding layer 6 of the sliding surface material 1 is located at the outermost periphery. (Fig. 13), and compression molding is performed in a mold to form a sealing body.

[Action/Effect]

Each manufacturing method of the present invention that differs from the above-described configuration has the following effects.

■Since multiple recesses are formed on the surface of the expanded graphite sheet by knurling, the conventional press drilling using needle-shaped objects does not require deburring after processing, and the complexity of the manufacturing process is eliminated. , workability can be greatly improved.

■The process of continuously knurling the surface of a long expanded graphite sheet and cutting it to the required length can be automated, which, together with the effect of ■ above, greatly improves work efficiency. Improved.

(2) The manufacturing process can be further significantly shortened by using a sliding surface material in which a sliding layer is formed on the surface of one end of a long expanded graphite sheet.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be explained in detail in the order of its steps with reference to the accompanying drawings.

<First step> Prepare an expanded graphite sheet 2 with a thickness of 0.8 mm ("Nika Film" manufactured by Nippon Carbon Co., Ltd.), and a height of 0.8 mm on the outer peripheral surface.
, - a pressure roller 3 equipped with a plurality of protrusions 3L each consisting of a square prism part with a side length of 1.0 mm and a square pyramid part at the tip of the square prism part; and a pressure roller 3 arranged in series with a gap S. The expanded graphite sheet 2 is supplied to a knurling tool N consisting of a guide roller 4 disposed in the knurling tool N, and the expanded graphite sheet 2 is passed through a gap S of the tool N (FIG. 1).

By this knurling process, a plurality of recesses 5 are formed on one surface of the expanded graphite sheet 2 (FIGS. 2 and 3).
The area ratio of the openings of the recesses 5 formed on the surface of the expanded graphite sheet 20 to the surface area of the graphite sheet was 28%.

Second step> The surface of the expanded graphite sheet 20 with a plurality of recesses 5 formed on one surface is filled with PTFE dispersion (solid content 60% by weight) (manufactured by Mitsui Fluorochemical Co., Ltd.) so as to fill the recesses 5 as well. Spray with Teflon 30JJ).

Next, the sliding surface material 1 was dried by heating at a temperature of 120° C. for 5 minutes to form a sliding layer 6 made of PTFE on the surface.
was obtained (Figure 4).

Third Step> Using 5t JS403 with a wire diameter of 0.28 mm as the fine metal wire, a braided band-shaped wire mesh 8 with a mesh size of 3 cm was created, and this was used as a reinforcing material.

On the other hand, as the heat-resistant sheet material 9, an expanded graphite sheet is separately prepared, and after the expanded graphite sheet and the braided wire mesh 8 are overlapped, the wire mesh 8 is placed on the outermost periphery with the expanded graphite sheet inside. A cylindrical body 10 was created by winding it (FIG. 7).

<Fourth step> The sliding surface material l obtained in the second step is wrapped around the outer circumferential surface of the cylindrical body 10 with the sliding surface N6 made of PTFE on the outside (FIG. 8), and a partially concave spherical surface portion is formed on the inner surface. 11, and compression molded in the axial direction within the mold 12 at a molding pressure of 2.5 tons/cWI' (FIG. 9).

In this step, the gold w constituting the reinforcing material of the cylindrical body 10 is
48 are intertwined with each other, and a heat-resistant sheet material 9 is crushed and embedded around them, and has a circular hole 14 on the inner surface and a partially convex spherical surface part 15 on the outer surface, and a sliding layer made of PTFE on the surface of the partially convex spherical surface part 150. A spherical seal body 16 having 6 formed thereon was obtained (FIG. 10).

It was confirmed that the performance of the spherical seal body 16 obtained through the manufacturing process of the above-mentioned example, that is, the frictional characteristics, the prevention of abnormal noise generation, and the sealing function, was equivalent to the performance of the spherical seal body of the prior art (2).

[Brief Description of the Drawings] Figure 1 is a side view showing the knurling process, Figure 2 is a plan view showing an expanded graphite sheet with a plurality of recesses formed on its surface, and Figure 3 is Figure 2 I-1. A line sectional view, FIG. 4 is a sectional view showing a sliding surface material, and FIG. 5 is a sectional view showing another edge surface material.
Fig. 6 is a sectional view showing another sliding surface material, Fig. 7 is a plan view showing the cylindrical body, Fig. 8 is a plan view showing the state in which the sliding surface material is wrapped around the outer peripheral surface of the cylindrical body, and Fig. 9 The figure is a sectional view showing the state of compression molding using a mold, FIG. 10 is a sectional view showing a spherical seal body, FIGS. 11 and 12 are plan views and sectional views showing other sliding surface materials, and FIG. FIG. 14 is a plan view showing a cylindrical body, FIG. 14 is a cross-sectional view showing a conventional processing tool, and FIG. 15 is a cross-sectional view of a sheet in a processed state. Explanation of symbols 1: Sliding surface material 2 5: Recess 6 7.8: Wire mesh 9 10: Cylindrical body 11 12: Mold 13 14: Circular hole 15 16: Spherical seal body Expanded graphite sheet Sliding layer Other heat-resistant sheet material parts Concave spherical part Core part Convex spherical part

Claims (3)

[Claims] (1) One side of the expanded graphite sheet was knurled to form multiple recesses on the surface, and a lubricant was applied to a predetermined thickness so as to fill these recesses to form a sliding layer. A band-shaped sliding surface material is wrapped around the outer circumferential surface of a cylindrical body formed by overlapping a reinforcing material made of wire mesh and a heat-resistant sheet material, and winding these into a cylindrical shape, with the above-mentioned sliding layer on the outside. 1. A method for manufacturing a seal body, which comprises inserting the seal body into the outer peripheral surface of a core of a mold having the shape and dimensions, and compression molding the seal body in the axial direction. (2) For the sliding surface material, one side of the expanded graphite sheet is knurled to form multiple recesses on the surface, and a lubricant is applied to the surface to a predetermined thickness so as to fill these recesses. After forming a sliding layer, it is inserted into a bag-shaped wire mesh and compressed in the direction of the sheet surface, or alternatively, a belt-shaped wire mesh is placed on the surface of the sliding layer and compressed in the direction of the sheet surface. 2. The method of manufacturing a seal body according to claim 1, wherein the seal body is compressed to form an integral body with a wire mesh. (3) Knurling the surface of one end of a long expanded graphite sheet over a predetermined length to form a plurality of recesses on the surface, and also fill the surface with a predetermined thickness so as to fill these recesses. The sliding surface material, which has been coated with lubricant to form a sliding layer on a part of the surface of the sheet, is overlapped with a reinforcing material made of wire mesh, and these are wound so that the sliding layer is located on the outermost surface to form a cylinder. 1. A method for manufacturing a seal body, which comprises forming a seal body, inserting the seal body into the outer peripheral surface of a core of a mold having a desired shape and dimensions, and compression molding the seal body in the axial direction.