JP3156967B2 - Seal body for exhaust pipe joint and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a seal used for a spherical joint of an automobile exhaust pipe and a method for manufacturing the same.

[Prior Art] Conventionally, as a seal member used for a spherical joint of an automobile exhaust pipe, for example, as disclosed in Japanese Patent Publication No. 58-21144 (hereinafter referred to as “prior art I”), a wire mesh and an inflatable seal member are used. A sheet-like refractory material such as graphite or mica is superimposed and wound into a cylindrical shape to form a cylindrical body, and then the cylindrical body is formed by compression molding in the axial direction of the cylindrical body, or As disclosed in JP-A-59-74326 (hereinafter referred to as "prior art II"), a mixture of a relatively short (2 mm to 8 mm) fiber and a solid lubricant such as graphite is formed by compression molding. There are things.

[Problems to be Solved by the Invention] In the seal body of the above-mentioned prior art I, the refractory material fills all the meshes and gaps of the wire mesh and the two are entangled with each other to have structural integrity. However, expanded graphite or mica used as a refractory material has a drawback that a friction coefficient (torque) is high in sliding with a mating material and an abnormal sound is often generated, and the sliding contact with the mating material is made. Unless the sliding surface is modified, there is a problem that it is difficult to put to practical use.

Further, the seal body made of the prior art II has an advantage that it can be manufactured more easily and at lower cost than the seal body made of the above-mentioned prior art I, but, like the seal body of the above-mentioned prior art I, the initial friction with the mating material is reduced. In the stage of, i.e., the stage in which the solid lubricant in the component forms a solid lubricating film on the surface of the mating material, the friction coefficient is high, which often causes the occurrence of abnormal noise, and the material constituting the seal body. In addition, due to a problem in manufacturing the seal body, there is a disadvantage that the strength of the seal body is reduced at the time of use, and partial destruction or breakage is caused to greatly reduce the function as the seal body.

That is, since the seal body has a spherical band shape having a through hole on the inner surface and a partially convex spherical surface portion on the outer surface, particularly when the seal body is manufactured, a small diameter of the outer surface part convex spherical portion of the inner surface through hole of the seal body is used. That is, a material-filled portion is formed in the portion (the end portion of the seal body), and pressure is not sufficiently applied even in the subsequent compression molding, and a portion having insufficient strength is generated in the portion. This leads to a serious problem that, during use of the seal body, breakage or loss occurs in the portion, causing leakage of exhaust gas.

In view of the above-mentioned problem (particularly the strength reduction) of the latter (prior art II) seal body, the inventors of the present invention have previously described Japanese Patent Application No.
No. 190155 (Japanese Patent Publication No. 2-26687; hereinafter referred to as "prior art").

That is, in the prior art, a ring-shaped reinforcing material formed by winding a metal mesh into a cylindrical shape, graphite, a solid lubricant such as molybdenum disulfide, a diameter of 10 to 200 μm, and a length of 100 to 800 μm
m, which is a mixture with a metal fiber of m. The mixture is a sealing body for an exhaust pipe joint which is formed by filling the mesh of the ring-shaped reinforcing material and compression-molding integrally with the reinforcing material.

This prior art seal has a diameter of metal fibers.
10-200μm, 100-800μm in length, using fine fibers, during the production of the seal body, to be densely filled without creating a dense portion in the mold, ring-shaped reinforcement made of metal mesh By using
This is to solve the problem of the decrease in the strength of the seal body made of the above-mentioned prior art II, and to greatly improve the strength as the seal body.

However, even in the seal body according to the prior art, another disadvantage of the seal body according to the prior art II is an initial stage of friction with a counterpart material, in other words, a solid lubricant such as graphite constituting the seal body. Is formed as a solid lubricating film on the surface of the mating material, and the friction coefficient is unstable at the stage before the seal and the mating material shift to friction through this film, and an abnormal sound is often generated. The disadvantages remain as problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sealing body which solves the problems at the initial stage of friction and a method for manufacturing the same, while taking advantage of the above-mentioned prior art as it is.

[Means for Solving the Problems] According to the present invention, the object described above is to provide a metal mesh or an expanded metal pipe used for a spherical pipe joint of an automobile exhaust pipe having a through hole on an inner surface and a partially convex spherical portion on an outer surface. A cylindrical lubricating material made of metal and a solid lubricant such as graphite or molybdenum disulfide filled with meshes of the cylindrical reinforcing material and compression-molded so as to cover the reinforcing material and having a diameter of 10 to 30% by weight;
50-70% by weight of metal fiber of ~ 200μm, length 100 ~ 800μm
And a resin binder of 2 to 20% by weight, on the surface of the partially convex spherical surface portion, a surface of which is mainly composed of ethylene tetrafluoride resin, graphite, metal sulfide and metal fluoride. The present invention is attained by a seal body for an exhaust pipe joint formed with a lubricating slip layer containing one or more fillers selected from boron nitride at a ratio of 40 to 50% by weight.

Further, according to the present invention, the above object is as follows: (a) a step of inserting a core holding a cylindrical reinforcing member made of a metal mesh or an expanded metal on an outer peripheral surface into a mold having a hollow portion on an inner surface; (B) 15 to 30% by weight of a solid lubricant such as graphite or molybdenum disulfide and a diameter of 10 to
A mixture composed of 50 to 70% by weight of metal fiber having a length of 200 μm and 100 to 800 μm and 2 to 20% by weight of a resin binder is charged, and the mixture is compressed in the axial direction of the core to provide a cylindrical reinforcing material on the inner surface. Obtaining a cylindrical preform, and (c) forming, on a surface of the outer peripheral surface of the preform, an ethylene tetrafluoride resin as a main component, a graphite, a metal sulfide, a metal fluoride, and boron nitride. 40 to 50 of one or more of the selected fillers
Forming a lubricating slip layer made of a lubricating composition blended at a ratio of weight percent; and (d) a cylindrical preform having the lubricating slip layer in a mold having a partially concave spherical portion on the inner surface. (E) compressing the cylindrical preform in the axial direction of the core, providing a through hole in which the reinforcing material is crushed and exposed on the inner surface, and the lubricating slip layer on the outer surface. Obtaining a molded seal having a uniformly formed partially convex spherical surface; and (f) placing the molded seal in a heating furnace;
The present invention is also achieved by a method of heating and curing the resin binder in the mixture, and a method of manufacturing a seal body for an exhaust pipe joint, comprising the above steps (a) to (f).

Next, constituent materials in the above-described exhaust pipe joint seal body and a method of manufacturing the same will be described.

(Cylindrical reinforcing material) As the cylindrical reinforcing material, a braided or woven metal mesh formed by weaving or knitting a thin wire of stainless steel or iron, or a so-called expanded metal provided with a continuous mesh on a thin metal plate is used. After these are wound at least once around the outer peripheral surface of the core, the overlapped portion is fixed by spot welding or a clasp and formed into a cylindrical shape, or is compressed in the core axial direction to form a cylindrical shape. And a braided metal mesh knitted in a cylindrical shape.

When a braided or woven metal mesh is used as the metal mesh, a fine wire having a diameter of about 0.02 to 0.32 mm is preferably used. The mesh (mesh) of the metal mesh and the expanded metal is preferably about 3 to 6 mm.

(Mixture) (A) Metal fiber Metal fiber is iron or an iron alloy containing iron as a main component, such as iron or steel, stainless steel, or a copper alloy containing copper or copper as a main component, such as bronze, phosphor bronze, lead bronze, or brass. , Aluminum bronze, or the like, which is cut from wool fibers formed by chattering or shaving from a wire strand is used. In particular, for fibers with a diameter of 10 to 200 μm and a length of 100 to 800 μm, forming a uniform mixture, enabling uniform filling in a mold at the time of manufacturing a seal body, and cylindrical reinforcing material Of the cylindrical reinforcing material and the mixture can be firmly integrated, for example, by allowing the filling of the mesh into meshes and by causing entanglement of the fibers.

These metal fibers are used alone or in combination.

(B) Solid Lubricant As the solid lubricant, powders such as graphite and molybdenum disulfide are used alone or in combination.

(C) Resin binder A phenol resin is used as the resin binder.

(A) Metal fiber, (B) solid lubricant, and (C)
The resin binder is put into a mixer and mixed with stirring to form a uniform mixture.

The mixing ratio of the mixture is 50 to 75% by weight of metal fiber, 15 to 30% by weight of solid lubricant, and 2 to 20% by weight of resin binder.
Is a preferable range.

In addition, inorganic powders such as calcium carbonate (CaCO ₃ ) and boron oxide (B ₂ O ₃ ) may be added to the mixture having the above-mentioned component compositions alone or as a mixture.

Although calcium carbonate and boron oxide do not exhibit any lubricity per se, they are blended in the above mixture to promote the film forming property of a solid lubricating film on the surface of a mating material of a solid lubricant, and to increase the friction of the seal body. It has the effect of improving the wear characteristics, preventing oxidation of the wear powder of the metal fibers caused by friction, and suppressing the abrasive action of the oxidized wear powder caused by the oxidation of the wear powder.

And these inorganic powders are 5 to 5% of the above mixture.
It can be blended at a ratio of 20% by weight.

(Preformed body) The preformed body is formed by compression-molding the above-mentioned cylindrical reinforcing material and a mixture filled over the reinforcing material, and the shape thereof is the inner diameter of a seal body as a final product. There is no particular limitation as long as it has a dimensional relation of a larger inner diameter, an outer diameter smaller than the outer diameter, and a high height, but a cylindrical one is preferable in consideration of workability and the like.

(Lubricant sliding layer) The lubricating sliding layer formed on the surface of the convex spherical surface on the outer surface of the seal body reduces the friction coefficient (torque) between the sealing material and the mating material, especially at the initial stage of friction, and is thus abnormal. It plays a role in preventing the generation of sound.

This lubricating slip layer is applied to the outer peripheral surface of the preformed body formed from the above-mentioned mixture of the cylindrical reinforcing material and the mixture by a method such as coating or spraying. It is formed with a uniform and minute thickness.

The outer peripheral surface of the preformed body on which the lubricating sliding layer is formed is relatively rough (uneven surface), and is subjected to a strong shearing force between the mold surfaces in the final compression step. The lubricating sliding layer is firmly integrated with the surface of the convex spherical portion on the outer surface of the seal body.

The lubricating sliding layer is mainly composed of tetrafluoroethylene resin (hereinafter referred to as “PTFE”),
It is formed by a lubricating composition containing one or more fillers selected from metal sulfides, metal fluorides and boron nitride in a proportion of 40 to 50% by weight.

Molybdenum disulfide, tungsten disulfide, antimony disulfide, and the like are used as metal sulfides that are mixed with PTFE as a main component to form a lubricating composition.Also, as metal fluorides, calcium fluoride, barium fluoride , Lithium fluoride and the like are used.

The metal fluoride itself is not a very low friction material, but when used in combination with PTFE, graphite, metal sulfide, boron nitride, etc., it prevents oxidative consumption at high temperatures and contributes to maintaining lubricity.

The lubricating composition is prepared by mixing an aqueous PTFE dispersion with the above-mentioned filler, or a mixture of a PTFE for lubrication with a filler and an adhesive (for example, an alkyd resin or a phenol resin) in a volatile solvent (for example, Xylene,
Dichloroethane, trichlorethylene, etc.), and is applied to the outer peripheral surface of the preform by a method such as coating or spraying with a brush.

Table 1 shows examples of preferred component compositions for the lubricating composition.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Example: I> A stainless steel wire with a wire diameter of 0.3 mm was used, and the mesh size was 5
A bag-shaped braided mesh of mm was prepared. The bag-shaped braided mesh is passed through a pressure roller to form a sheet, wound around the core outer circumference once, and then fixed to the spliced portion by spot welding and compressed in the axial direction of the core. Thus, a cylindrical reinforcing material 1 made of a braided mesh was formed.

The cylindrical reinforcing material 1 is fitted and inserted into an outer peripheral surface of a mold core 2 (FIG. 1), and the core 2 is inserted and fixed in a mold 4 having a cylindrical concave portion 3 on the inner surface (FIG. 2). ). On the other hand, graphite was used as a solid lubricant, and the graphite powder and a wire diameter of 100 μm were used.
A metal fiber made of steel having a length of 500 μm and a phenolic resin binder are put into a mixer and mixed by stirring to produce a uniform mixture 5 of the graphite powder, the steel fiber and the phenolic resin binder (mixing ratio). Was mixed with graphite: 18% by weight, steel fiber: 73% by weight, and phenolic resin binder: 9% by weight), and the mixture 5 was charged into the cylindrical recess 3 of the mold 4 (FIG. 3).

Then, the mixture 5 was pressed in the axial direction of the core 2 with a molding pressure of 1.
It was compression molded at ton / cm ² (FIG. 4) to produce a cylindrical preform 6 integrally provided with the cylindrical reinforcing material 1 on the inner surface. An aqueous dispersion (solid content: 60% by weight: manufactured by Mitsui Fluorochemicals Co., Ltd.) in which a PTFE solid having an average particle size of 0.1 μm or less was dispersed on the outer peripheral cylindrical surface of the cylindrical preformed body 6 thus obtained. tungsten disulfide (WS ₂₎ powder and graphite powder and entrained lubricating composition dispersion produced by mixing and stirring (solid PTFE: 50 wt%, WS _2: 40 wt%, graphite: 10% by weight) was applied Then, a lubricating sliding layer 7 was formed (FIG. 6).

The cylindrical preform 6 provided with the lubricating sliding layer 7 was fitted and held on the outer peripheral surface of the mold core 8, and the core 8 was inserted and fixed in the mold 10 having the partially concave spherical portion 9 on the inner surface. (7th
Figure).

Next, in the mold 10, the cylindrical preform 6
Is press-formed in the axial direction of the core 8 at a forming pressure of 3 ton / cm ² , and a through-hole in which the crushed cylindrical reinforcing material 1 is exposed on the inner surface.
A molded seal body 13 having a partially convex spherical portion 12 having a lubricating sliding layer 7 formed on the outer surface thereof and having a uniform and uniform micro-thickness formed on the outer surface and having a strong integral shape is obtained (FIG. 8). ).

Then, the molded sealing body 13 is placed in a heating furnace set at a temperature of 80 ° C. for 30 minutes to preheat, and then the resin binder in the mixture is cured by heating at a temperature of 180 ° C. for 2 hours, 14 was obtained (FIG. 9).

<Example: II> A cylindrical reinforcing material 1 made of a braided mesh is formed in the same manner as in Example I, and the cylindrical reinforcing material 1 is fitted and inserted into the outer peripheral surface of the mold core 2. The core 2 was inserted and fixed in a mold 4 having a cylindrical concave portion 3 on the inner surface.

On the other hand, graphite was used as a solid lubricant, and the graphite powder, a metal fiber made of steel having a wire diameter of 100 μm and a length of 500 μm, and calcium carbonate powder and a phenolic resin binder as inorganic powders were put into a mixer and stirred and mixed. To prepare a uniform mixture 5 of graphite powder, steel fiber, calcium carbonate powder and phenolic resin binder (the mixing ratio is 18% by weight of graphite powder, 65% by weight of steel fiber, 10% by weight of calcium carbonate powder,
(Phenol resin binder: 7% by weight), and the mixture 5 was charged into the cylindrical recess 3 of the mold 4.

Then, the mixture 5 was pressed in the axial direction of the core 2 with a molding pressure of 1.
A compression molding was performed at ton / cm ² to produce a cylindrical preform 6 integrally provided with the cylindrical reinforcing material 1 on the inner surface. A graphite powder, a tungsten disulfide (WS ₂ ) powder and calcium fluoride (CaF ₂ ) are mixed into an aqueous PTFE dispersion (solid content: 60%) and mixed with stirring on the outer peripheral cylindrical surface of the cylindrical preform 6. Lubricating composition dispersion (solid content PTFE: 50
Wt%, graphite: 20% by weight, WS _2: 20 wt%, CaF _2: 10 wt%) was applied to form a lubricating sliding layer 7.

The cylindrical preform 6 provided with the lubricating sliding layer 7 was fitted and inserted into the outer peripheral surface of the mold core 8, and was inserted and fixed in the mold 10 having the partially concave spherical portion 9 on the inner surface of the core 8. . In the mold 10, the cylindrical preform 6 is compression-molded in the axial direction of the core 8 at a molding pressure of 3 ton / cm ² , and a through-hole 11 in which the crushed cylindrical reinforcing material 1 is exposed on the inner surface. , And a molded sealing body 13 having a partially convex spherical portion 12 on the outer surface of which the lubricating sliding layer 7 is stretched to a uniform and uniform fine thickness and which is firmly and integrally formed.

Then, the molded sealing body 13 is placed in a heating furnace set at a temperature of 80 ° C. for 30 minutes to preheat, and then the resin binder in the mixture is cured by heating at a temperature of 180 ° C. for 2 hours, I got 14.

Comparative Example A cylindrical reinforcing material was formed in the same manner as in Example I. The cylindrical reinforcing material was fitted and inserted into the outer peripheral surface of a mold core, and the core was inserted and fixed in a mold having a cylindrical concave portion on the inner surface.

Next, graphite was used as a solid lubricant in the partially concave spherical portion of the mold, and the graphite powder was combined with a wire having a wire diameter of 100 μm and a length of 500 μm.
A uniform mixture of a metal fiber made of μm steel and a phenolic resin binder (mixing ratio: graphite: 18% by weight, steel fiber: 73
Wt%, phenolic resin binder: 9 wt%).

In the mold, the mixture is compression-molded in the axial direction of the core at a molding pressure of 3 ton / cm ² , a through-hole in which a crushed cylindrical reinforcing material is exposed on the inner surface, and a partially convex spherical portion on the outer surface. Was obtained.

Then, the molded seal was pre-heated in a heating furnace set at a temperature of 80 ° C. for 30 minutes, and then heated at a temperature of 180 ° C. for 2 minutes.
For a time, the resin binder in the mixture was cured by heating to obtain a sealed body.

Next, the results of tests on the seal body composed of the above-described Examples and Comparative Examples for the friction torque (kgf · cm), the generation of abnormal noise, and the sealing function of the seal body in the initial stage of friction of the seal body will be described.

<Regarding the coefficient of friction, the occurrence of abnormal noise, and the sealing function of the seal body at the time of initial friction of the seal body> The test method was based on the above-described Examples I and II and Comparative Example, and the outer surface had a convex spherical surface with a curvature radius of 30 mm. Producing a seal body having a portion, attaching the seal body to one end of the pipe,
It is slid in contact with the stainless steel concave spherical portion provided on the other end of the pipe under the following conditions, frictional torque at the initial stage of friction at the slidable contact portion, generation of abnormal noise, and gas leakage from the joint portion The amount was tested.

FIG. 11 shows the test apparatus (in a state where the seal body is attached to the spherical pipe joint).

In the figure, reference numeral 20 denotes a downstream side exhaust pipe, and a concave spherical portion 21 whose diameter is enlarged like a bosh toward the end is formed at the end of the exhaust pipe 20.

Reference numeral 30 denotes an upstream exhaust pipe, and a flange 32 is fixed to the exhaust pipe 30 except for a pipe end 31. The upstream exhaust pipe 30
A seal body 14 is provided on the outer peripheral surface of the tube end 31
Is mounted in sliding contact with the concave spherical portion 21 of the downstream side exhaust pipe 20, and the large-diameter end surface of the outer convex spherical portion 12 is in sliding contact with the flange 32.

One end of each of the upper and lower exhaust pipes 20 and 30 is connected to the upstream exhaust pipe.
A pair of headed bolts 40, which are screwed and fixed to a flange 32 fixed to 30 and the other end of which is inserted through a flange 22 fixed to the downstream side exhaust pipe 20, and the flange 22 and the bolt The head 40 is connected to the head 40 by a pair of coil springs 50 that are always biased in the direction of the exhaust pipe 30 on the upstream side.

(Test conditions) Pressing force 60kg Oscillation angle ± 3 ゜ Frequency 100 Hz Ambient temperature Room temperature to 500 ° C Pipe pressure 0.5kg / cm ² Test method: ± 3 ゜ oscillating motion at 10 Hz frequency
After performing 45,000 times at room temperature, the ambient temperature was raised to 500 ° C. while continuing the exercise (the number of oscillations during the temperature rise was 4).
5,000 times), when the ambient temperature reaches 500 ° C, 11
Perform 5,000 rocking movements, then lower the ambient temperature to room temperature while continuing the movement (45,000 rocking cycles during cooling).
Is performed for 4 cycles with 1 cycle being the total number of swings of 250,000.

The evaluation of the occurrence of abnormal noise was performed as follows.

 Evaluation symbol I: No abnormal noise.

Evaluation symbol II: An abnormal sound can be heard slightly with the ear close to the test piece.

Evaluation symbol III: The sound is muted by the living environment sound at a fixed position (at a position 1.5 m away from the test piece) and is generally indistinguishable.

Evaluation symbol IV: A symbol that can be identified as an abnormal sound (unpleasant sound) at a fixed position by anyone.

 Table 2 shows the test results.

From the test results, it was found that the seal of the present invention, that is, Example I
The seal body of Example II had a low friction torque at the initial stage of friction with the counterpart material, and showed stable performance throughout the test period without occurrence of abnormal noise.

On the other hand, in the seal body of the comparative example, the friction torque was high in the initial stage of the friction with the counterpart material, the fluctuation amount was large, and the occurrence of abnormal noise was recognized.

Observation of each seal body and the mating material friction surface of the example and the comparative example after the test confirmed that a solid lubricating film (graphite film) was formed on each friction surface. After formation, that is, in the above test, no significant difference in performance was observed between the example and the comparative example in friction after 750,000 cycles.

From the above test results, the seal body of the present invention having the lubricating sliding layer on the outer surface convex spherical portion exhibits excellent performance at the initial stage of friction with the mating material, taking advantage of the prior art, and It was able to solve the shortcomings of the technology.

FIG. 10 shows another embodiment of the seal body 14, in which the cylindrical reinforcing material 1 is crushed and exposed near the small diameter portion of the convex spherical portion 12 on the outer surface of the inner through hole 11 of the seal body 14. . The seal body according to this embodiment also exhibits the same performance as described above.

[Effects] The present invention has the above-described configuration and has the following specific effects.

The sealing body of the present invention comprises, on the outer surface convex spherical portion, one or two or more kinds of fillers selected from graphite, metal sulfide, metal fluoride, and boron nitride, mainly composed of ethylene tetrafluoride resin. Is formed in a lubricating composition composed of 40 to 50% by weight, so that the friction torque is low especially at the initial stage of friction with the partner material, no abnormal noise is generated, and the initial friction Demonstrate stable performance over a long period of time.

One or more fillers selected from graphite, metal sulfides, metal fluorides, and boron nitride are mainly composed of ethylene tetrafluoride resin formed on the convex spherical surface portion of the outer surface of the seal body. The lubricating sliding layer made of a lubricating composition blended at a ratio of 40 to 50% by weight is a relatively rough surface (uneven surface) formed by compression-molding a mixture of a solid lubricant, a metal fiber, and a resin binder into a cylindrical shape. ) Is applied to the outer peripheral surface of the preformed body, and is formed by receiving a strong shearing force between the dies in the final compression step, so that a strong integration is performed on the outer peripheral surface of the seal body.

[Brief description of the drawings]

1 is a perspective view showing a cylindrical reinforcing member inserted into the outer peripheral surface of the core, FIG. 2 is a longitudinal sectional view showing a state in which the cylindrical reinforcing member is arranged in a mold, and FIG. 3 is shown in FIG. FIG. 4 is a longitudinal sectional view showing a state in which the mixture is loaded in a mold, FIG. 4 is a longitudinal sectional view showing a state in which the mixture shown in FIG. 3 is compression molded, FIG. 6 is a longitudinal sectional view showing a preformed body having a lubricating slip layer formed on an outer peripheral surface, FIG. 7 is a longitudinal sectional view showing a state where the preformed body shown in FIG. 6 is arranged in a mold,
FIG. 8 is a longitudinal sectional view showing a state in which a preformed body is compression-molded in a mold to form a molded seal body, FIG. 9 is a longitudinal sectional view showing the seal body, and FIG. FIG. 11 is a longitudinal sectional view showing an embodiment, and FIG. 11 is a longitudinal sectional view showing a test apparatus (exhaust pipe spherical joint). DESCRIPTION OF SYMBOLS 1 ... Cylindrical reinforcing material, 2 ... Die core 3 ... Cylindrical recessed part 4 ... Die 5 ... Mixture, 6 ... Preformed body 7 ... Lubricating sliding layer, 8 ... Die core 9 ... Partially concave spherical surface part, 10 ... Mold 11 ... Through hole, 12 ... Partially convex spherical part 13 ... Molded seal body, 14 ... Seal body

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-36913 (JP, A) JP-A-62-37569 (JP, A) JP-A-59-131723 (JP, A) JP-A-59-131723 74326 (JP, A)

Claims (8)

(57) [Claims] 1. A cylindrical reinforcing member 1 made of a metal mesh or expanded metal and used for a spherical joint of an automobile exhaust pipe having a through hole 11 on an inner surface and a partially convex spherical portion 12 on an outer surface. A solid lubricant such as graphite, molybdenum disulfide or the like, which is filled with the mesh of the reinforcing material 1 and is integrally formed by compression over the reinforcing material 1, has a diameter of 10 to 200%.
In a sealed body made of a mixture 5 of 50 to 70% by weight of a metal fiber having a length of 100 to 800 μm and a resin binder of 2 to 20% by weight, the surface of the partially convex spherical portion 12 has A lubricating composition comprising a resin as a main component and one or more fillers selected from graphite, metal sulfide, metal fluoride, and boron nitride in a proportion of 40 to 50% by weight. A seal body for an exhaust pipe joint, wherein a slip layer 7 is formed. 2. The exhaust pipe joint seal according to claim 1, wherein the cylindrical reinforcing material is exposed by being crushed over the entire length of the inner surface through hole of the seal. 3. The seal body for an exhaust pipe joint according to claim 1, wherein the cylindrical reinforcing material is exposed to the seal body by being crushed in the vicinity of the small diameter portion of the convex spherical portion on the outer surface of the inner surface through hole. 4. The exhaust pipe joint seal according to claim 1, wherein the mixture further contains an inorganic powder selected from calcium carbonate and boron oxide at a ratio of 2 to 20% by weight. 5. A step of: (a) inserting a core holding a cylindrical reinforcing material made of metal mesh or expanded metal on the outer peripheral surface into a die having a hollow portion on the inner surface; and (b) the die. Solid lubricant such as graphite, molybdenum disulfide, etc. 15-30% by weight, diameter 10-200μm, length 100
50-70% by weight of metal fiber of ~ 800μm and resin binder 2-20
% By weight, and compressing the mixture in the axial direction of the core to obtain a cylindrical preform having a cylindrical reinforcing material on the inner surface thereof. The surface is composed mainly of ethylene tetrafluoride resin, and one or more fillers selected from graphite, metal sulfide, metal fluoride, and boron nitride are blended at a ratio of 40 to 50% by weight. Forming a lubricating slip layer made of the lubricating composition thus obtained; and (d) inserting a core holding the cylindrical preform having the lubricating slip layer into a mold having a partially concave spherical portion on the inner surface. (E) compressing the cylindrical preform in the core axis direction, providing a through hole on the inner surface where the reinforcing material is crushed and exposed, and a portion where the lubricating slip layer is uniformly formed on the outer surface A step of obtaining a molded seal body having a convex spherical portion; and (f) the molded seal. It was placed in a heating furnace, a step of heating and curing the resin binder in the mixture, or (a) to the production method of the exhaust pipe joint sealing body, comprising the steps of (f). 6. The method for manufacturing a seal body for an exhaust pipe joint according to claim 5, wherein the cylindrical reinforcing material is crushed and exposed over the entire length of the inner surface through hole of the seal body. 7. The manufacture of a seal body for an exhaust pipe joint according to claim 5, wherein the cylindrical reinforcing material is crushed and exposed to the vicinity of a small diameter portion of the convex spherical portion on the outer surface of the inner surface through hole in the seal body. Method. 8. The exhaust pipe joint sealing body according to claim 5, wherein the mixture further contains an inorganic powder selected from calcium carbonate and boron oxide at a ratio of 2 to 20% by weight. Manufacturing method.