JP4953222B2 - Sphere seal - Google Patents

Description

  The present invention relates to a ball-shaped seal body used for a spherical pipe joint of an automobile exhaust pipe.

Japanese Patent Publication No.58-21144 JP 58-24619 A

  As shown in FIG. 15, the exhaust gas of an automobile engine is generally guided to an exhaust manifold 600, and is released into the atmosphere from a tail pipe 605 through a catalyzing converter 601, an exhaust pipe 602, a pre-chamber 603, and a silencer 604. However, this exhaust system component is repeatedly subjected to stress due to the roll behavior and vibration of the engine 606. Particularly in the case of a high-speed engine with high speed rotation, the stress applied to the exhaust system parts is considerably large. Therefore, there is a possibility of causing fatigue failure of exhaust system parts. In addition, engine vibration may cause exhaust system parts to resonate and worsen vehicle interior quietness.

  In order to solve such a problem, means such as disposing a spherical pipe joint at a required portion of the exhaust pipe to absorb stress is taken.

  As a spherical belt-like seal body used for this spherical pipe joint, there is a seal body disclosed in Patent Document 1. While this seal body has the heat resistance, excellent compatibility with the mating material, and the impact strength has been significantly improved, it often generates frictional noise in friction under dry friction conditions. There is a drawback of doing. The disadvantage of this seal body is that the difference between the coefficient of static friction and the coefficient of dynamic friction of the heat-resistant material (expanded graphite, etc.) forming the seal body is large, and that the seal body made of this heat-resistant material is negative with respect to the sliding speed. This may be due to resistance (a phenomenon in which the coefficient of friction decreases as the sliding speed increases).

  There exists a sealing body disclosed by patent document 2 as what eliminates the fault of the said sealing body. This seal body is a seal obtained by shaping together with a reinforcing material made of a metal mesh obtained by weaving or knitting a thin metal wire with a heat resistant material mixed with one or more of expanded graphite, mica, and asbestos. A lubricating composition made of ethylene tetrafluoride resin or ethylene tetrafluoride-hexafluoropropylene copolymer is deposited on the surface of the sealing body. This sealing body has a lubricating composition deposited on the surface, reducing the friction coefficient, preventing the heat-resistant material forming the base material from being transferred to the surface of the counterpart, reducing the difference between the static friction coefficient and the dynamic friction coefficient, In addition, the tetrafluoroethylene resin does not exhibit negative resistance against the sliding speed, so combined with the above-described effects, the self-excited vibration based on “adhesion-slip” is generated. It has the effect of suppressing and contributing to the prevention of abnormal noise.

  The sealing body disclosed in Patent Document 2 solves the problem of the sealing body disclosed in Patent Document 1, but the applicable ambient temperature of the sealing body disclosed in Patent Document 2 is not covered on the surface. The problem is that it is left to the heat resistance of the formed lubricating composition and is naturally limited to use at an ambient temperature of around 300 ° C, and the exhaust pipe when used in a spherical pipe joint of an automobile exhaust pipe. Due to the action of the heat of the exhaust gas flowing through, the lubricating composition deposited on the surface of the sealing body melts, and the molten lubricating composition adheres to the surface of the counterpart material when the exhaust pipe is cooled after the engine is stopped. There is a problem of inhibiting the relative angular displacement of the spherical pipe joint.

  This phenomenon of sticking to the surface of the mating material is particularly due to the temperature condition of the exhaust pipe that melts the lubricating composition deposited on the surface of the seal body and to the part where the relative angular displacement applied to the spherical pipe joint is small. Prominent in application. If such a sticking phenomenon occurs, it is difficult to achieve the initial purpose of the spherical pipe joint, and if a large relative angular displacement is applied to the spherical pipe joint after the engine is restarted, a large abnormal sound ( This causes a problem of generating abnormal frictional noise.

  The present invention has been made in view of the above points, and the object of the present invention is to provide an outer layer having excellent retention on the surface, and the phenomenon of fixing the outer layer to the surface of the counterpart material due to the action of the heat of the exhaust gas. An object of the present invention is to provide a spherical belt-like seal body that is avoided and does not generate abnormal noise (abnormal friction noise).

  The spherical belt-shaped sealing body of the present invention includes a spherical belt-shaped substrate defined by a cylindrical inner surface, a partially convex spherical surface, a large-diameter side and a small-diameter annular end surface of the partially convex spherical surface, and a partial convex of the spherical belt-shaped substrate. An outer layer having a partially convex spherical outer surface that is formed integrally with a spherical surface and exposed to the outside, and is used particularly for an exhaust pipe joint, and the spherical base is compressed It includes a reinforcing material made of a wire mesh, and a heat-resistant material made of expanded graphite that is filled with the reinforcing material and meshed together and compressed, and the outer layer is made of expanded graphite. A heat-resistant material, a reinforcing material composed of a wire mesh mixed and integrated with the heat-resistant material, and fired fluorine which is integrated with the heat-resistant material and the reinforcing material and contains 1 to 15% by weight of graphite powder A resin composition and exposed to the outside of the outer layer The partially convex spherical outer surface is a smooth surface of a baked fluororesin composition containing 1 to 15% by weight of the graphite powder.

  According to the spherical belt-shaped sealing body of the present invention, the partially convex spherical outer surface that is in sliding contact with the mating member becomes a smooth surface of the baked fluororesin composition containing 1 to 15% by weight of graphite powder. As a result, it is possible to avoid a melting phenomenon caused by the action of the heat of the exhaust gas in the outer layer on the partially convex spherical outer surface. Further, in the sliding friction between the partially convex spherical outer surface exposed to the outside of the outer layer and the mating material surface, a lubricating film of graphite powder contained in the fluororesin composition is formed on the mating material surface. Even if the ambient temperature of the pipe joint part exceeds 450 ° C and the fluororesin in the outer layer disappears, the heat-resistant material in the outer layer shifts to sliding friction with the lubricating coating formed on the surface of the mating material. The relative angular displacement of the joint part is allowed without generating abnormal frictional noise.

  The graphite powder contained in the fluororesin is formed as a lubricating film on the surface of the mating material in the sliding friction between the partially convex spherical outer surface and the mating material, and intervenes on the sliding friction surface between the partially convex spherical outer surface and the mating material surface. Play a role in preventing the occurrence of abnormal noise. When the blending ratio with respect to the fluororesin is less than 1% by weight, the above-mentioned effects are not exhibited. When the blending ratio exceeds 15% by weight, the lubricity of the fluororesin is impaired, and the coating operation in the manufacturing method described later causes a problem. . Therefore, the blending ratio of the graphite powder to the fluorine resin is 1 to 15% by weight, preferably 3 to 10% by weight, and more preferably 4 to 8% by weight.

  In the spherical belt-shaped sealing body of the present invention, the heat-resistant material made of expanded graphite of the spherical belt-shaped substrate may be exposed on the inner surface of the cylinder. According to such a spherical belt-shaped sealing body, the spherical belt-shaped sealing body is the exhaust pipe. When fixed to the outer surface, the sealing performance between the cylindrical inner surface of the spherical base and the outer surface of the exhaust pipe is enhanced by a heat-resistant material made of expanded graphite on the inner surface of the cylinder, so that leakage of exhaust gas through the contact surface Can be prevented as much as possible.

  In the spherical belt-shaped sealing body of the present invention, the reinforcing member made of a metal mesh of the spherical belt-shaped substrate may be exposed on the inner surface of the cylinder, and according to such a spherical belt-shaped sealing body, the spherical belt-shaped sealing body is disposed on the outer surface of the exhaust pipe. When fitted and fixed, the friction between the inner surface of the cylinder and the outer surface of the exhaust pipe is increased by a reinforcing material made of a wire mesh on the inner surface of the cylinder, and as a result, the ball-shaped seal body is firmly fixed to the outer surface of the exhaust pipe. Will be.

  In the present invention, the fluororesin is an ethylene tetrafluoride resin (hereinafter abbreviated as PTFE), a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter abbreviated as PFA), an ethylene tetrafluoride-6 hexafluoride. It may be selected from a propylene fluoride copolymer (hereinafter abbreviated as FEP) and an ethylene-tetrafluoroethylene copolymer (hereinafter abbreviated as ETFE).

  According to the present invention, the partially convex spherical outer surface is a smooth surface of a baked fluororesin containing 1 to 15% by weight of graphite powder, and as a result, the outer layer on the partially convex spherical outer surface. In the sliding contact between the outer surface of the outer layer and the partially convex spherical outer surface exposed to the outside of the outer layer and the mating material surface, a lubricating coating of graphite powder contained in the fluorine resin can be avoided. As a result of being formed on the surface of the mating member, it is possible to provide a ball-shaped seal body in which the relative angular displacement of the spherical pipe joint portion is allowed without generating abnormal frictional noise.

  Next, an example of an embodiment of the present invention will be described in more detail based on the drawings. The present invention is not limited to these examples.

<About heat-resistant sheet material>
A heat resistant sheet material made of expanded graphite is used as the heat resistant sheet material. Expanded graphite is used in the form of a sheet with a thickness of 0.2 mm to 1.0 mm, such as “Grafoil (trade name)” manufactured by Union Carbide, Inc. or “Nika Film (trade name)” manufactured by Nippon Carbon Co., Ltd. Being preferred.

<About reinforcing material>
The reinforcing material is austenitic SUS304 or SUS316 as iron-based, stainless steel wire such as SUS430 or ferritic SUS430, iron wire (JIS-G-3532) or galvanized iron wire (JIS-G-3547), and copper- Weaving or knitting using one or two or more fine wires with a wire diameter of about 0.10 to 0.32 mm made of nickel alloy (white copper), copper-nickel-zinc alloy (white), brass, and beryllium copper It is preferable to use a wire net having a mesh size of about 3 mm to 6 mm.

<About fluorine resin>
The fluororesin composition for forming the coating layer is selected from PTFE, PFA, FEP and ETFE, and is 1 to 15% by weight, preferably 3 to 10% by weight, more preferably 4 to 8% by weight based on these fluororesins. % Of graphite powder is contained.

<About the manufacturing method of a ball-shaped seal body>
(First Step) As shown in FIG. 3, a strip metal mesh 4 having a predetermined width D is produced by passing a cylindrical wire mesh 1 formed by knitting a thin metal wire into a cylindrical shape between rollers 2 and 3, thereby forming the strip wire mesh. A reinforcing material 5 prepared by cutting 4 into a predetermined length L or a band metal mesh 4 directly formed by weaving or knitting a thin metal wire is prepared into a predetermined width D and length L. To do.

  (Second Step) As shown in FIG. 4, the width d of the reinforcing material 5 is 1.1 × D to 2.1 × D and the width L of the reinforcing material 5 is 1. A heat-resistant sheet material 6 made of expanded graphite cut to have a length l of 30 × L to 2.70 × L is prepared.

  (Third Step) In a spherical belt-like sealing body 30 (see FIG. 1), which will be described later, the large-diameter annular end surface 31 which is an annular end surface on the at least one end side in the axial direction of the partially convex spherical surface 29 is totally heat resistant. In order to expose the material, as shown in FIG. 5, 0.1 × from at least one edge 7 in the width direction of the reinforcing material 5 which becomes the annular end surface 31 on the large diameter side of the partially convex spherical surface 29. The heat-resistant sheet material 6 protrudes in the width direction by 0.8 × D from D, and the protrusion amount δ1 of the heat-resistant sheet material 6 from the end edge 7 in the width direction becomes the annular end surface 32 on the small diameter side of the partially convex spherical surface 29. The amount of protrusion δ2 from the other end edge 8 in the width direction of the reinforcing member 5 is increased, and 0.30 × L to 1.70 × L from one end edge 9 of the reinforcing member 5 in the length direction. Only the heat-resistant sheet material 6 protrudes in the length direction and the other of the reinforcing material 5 in the length direction. The edge 10 and the edge 11 in the length direction of the heat-resistant sheet material 6 corresponding to the edge 10 are substantially matched, and the width direction and the length direction of the reinforcing material 5 and the heat-resistant sheet material 6 are matched. Thus, a polymer 12 in which the reinforcing material 5 and the heat-resistant sheet material 6 are superposed on each other is obtained.

  (Fourth step) The polymer 12 is spirally wound with the heat-resistant sheet material 6 inside as shown in FIG. 6 and is wound so that the heat-resistant sheet material 6 is increased once. A cylindrical base material 13 with the heat-resistant sheet material 6 exposed on both sides is formed. As the heat-resistant sheet material 6, from 1.30 × L to the length L of the reinforcing material 5 so that the number of windings of the heat-resistant sheet material 6 in the cylindrical base material 13 is larger than the number of windings of the reinforcing material 5. Those having a length l of 2.70 × L are prepared in advance. In the cylindrical base material 13, as shown in FIG. 7, the heat-resistant sheet material 6 protrudes from the one edge 7 of the reinforcing material 5 by δ1 in the width direction on one edge side in the width direction. On the other edge side of the sheet material 6 in the width direction, δ2 protrudes from the other edge 8 of the reinforcing material 5 in the width direction.

  (Fifth Step) As shown in FIG. 8, which is the same as the heat-resistant sheet material 6, but has a width d smaller than the width D and a length l enough to wind the cylindrical base material 13 once. A heat-resistant sheet material 6 is prepared separately. On the other hand, as described in the first step, after forming the cylindrical wire mesh 1 by knitting a thin metal wire, a reinforcing material 5 made of the belt-like wire mesh 4 produced by passing the wire between the rollers 2 and 3 is prepared separately. As shown in FIG. 9, the separately prepared heat-resistant sheet material 6 is inserted into the reinforcing material 5. On the other hand, graphite powder is used at a ratio of 0.6 to 10.6 parts by weight with respect to 100 parts by weight of an aqueous dispersion (solid content 60%, moisture 40%) of a fluororesin selected from PTFE, PFA, FEP and ETFE. An aqueous dispersion of the fluorine resin composition contained (coating material: 85 to 99% by weight of fluorine resin, 1 to 15% by weight of graphite powder) is prepared, and the aqueous dispersion is applied by means of brushing, roller coating, spraying or the like. Further, a heat-resistant sheet coated with one surface of a separately prepared heat-resistant sheet material 6 having the same dimensions as the heat-resistant sheet material 6 shown in FIG. 8 and coated with such an aqueous dispersion (coating material) The material 6 is fired at a temperature not lower than the melting point of the fluororesin and not higher than the decomposition point for 5 minutes to 10 minutes, and the fluororesin composition is fired as shown in FIG. The coating layer 14 formed by forming the heat-resistant sheet member 6. As shown in FIG. 9, the heat-resistant sheet material 6 having the coating layer 14 formed on one surface thereof was inserted into the above-described inside of the surface opposite to the surface on which the coating layer 14 was formed. As shown in FIG. 11, they are superposed on the reinforcing material 5 so as to be in contact with the reinforcing material 5 made of the band-shaped wire mesh 4, and as shown in FIG. An outer layer forming member 17 is formed which is composed of another reinforcing material 5 made of a strip-shaped wire mesh 4 disposed so as to cover the other heat resistant sheet material 6 and a heat resistant sheet material 6 having a coating layer 14 made of a fluororesin composition on the surface. .

  (Sixth Step) The outer layer forming member 17 obtained in this way is wound around the outer peripheral surface of the cylindrical base material 13 to produce a preliminary cylindrical molded body 18 as shown in FIG.

  (Seventh step) A cylindrical wall surface 20, a partially concave spherical wall surface 21 continuous to the cylindrical wall surface 20, and a through hole 22 continuous to the partially concave spherical wall surface 21 are provided on the inner surface, and a stepped core 23 is fitted into the through hole 22. A mold 26 as shown in FIG. 13 having a cylindrical hollow portion 24 and a spherical belt-shaped hollow portion 25 connected to the cylindrical hollow portion 24 formed therein is prepared, and preliminary cylindrical molding is performed on the stepped core 23 of the mold 26. Insert body 18.

The preliminary cylindrical molded body 18 positioned in the cylindrical hollow portion 24 and the spherical belt-shaped hollow portion 25 of the mold 26 is compression-molded at a pressure of 1 ton / cm ^{2 to} 3 ton / cm ^{2 in} the core axial direction. As shown in FIG. 2, it has a through hole 27 in the center and is defined by a cylindrical inner surface 28, a partially convex spherical surface 29, and annular end surfaces 31 and 32 on the large diameter side and small diameter side of the partial convex spherical surface 29. A spherical belt-shaped sealing body 30 including the spherical belt-shaped substrate 33 and the outer layer 34 formed integrally with the partially convex spherical surface 29 of the spherical belt-shaped substrate 33 is produced.

  By this compression molding, the spherical belt-shaped substrate 33 is compressed so that the heat-resistant material made of the heat-resistant sheet material 6 and the reinforcing material 5 made of the belt-shaped wire mesh 4 are entangled with each other and have structural integrity. A reinforcing material 5 made of a strip-shaped wire mesh 4 and a heat-resistant material made of expanded graphite which is packed together with the reinforcing material 5 and compressed by being mixed with the reinforcing material 5. The outer layer 34 is made of a heat-resistant material made of expanded graphite in which the heat-resistant sheet material 6 is compressed, a reinforcing material made of a banded wire mesh 4 mixed and integrated with the heat-resistant material, and integrated with the reinforcing material 5 and the heat-resistant material. The partially convex spherical outer surface 35 exposed to the outside in the outer layer 34 is formed on a smooth surface containing the fluororesin composition of the coating layer 14, and the through hole 27. The cylindrical inner surface 28 that defines Heat-resistant material of the spherical annular base member 33 made of a heat-resistant sheet member 6 which is is formed by exposure.

  In the spherical belt-shaped sealing body 30 shown in FIG. 1 manufactured by the method described above, the heat-resistant sheet material 6 is intertwined with the reinforcing material 5 formed of the belt-shaped wire mesh 4 forming the internal structure, and is partially convex spherical. The outer surface 35 is formed on a smooth surface containing the fluororesin composition of the coating layer 14, and the large-diameter-side annular end surface 31 and the small-diameter-side annular end surface 32 of the partially convex spherical surface 29 are formed from the reinforcing material 5. The protruding heat-resistant sheet material 6 is bent and spread to form a heat-resistant material made of expanded graphite.

  In the fourth step, instead of winding the polymer 12 in a spiral shape with the heat-resistant sheet material 6 on the inside, the polymer base material 13 is wound in a spiral shape with the reinforcing material 5 made of the band-shaped wire mesh 4 inside. When formed, the spherical band-shaped sealing body 30 in which the reinforcing member 5 made of a wire net of the spherical band-shaped substrate 33 is partially exposed on the cylindrical inner surface 28 can be manufactured.

  The spherical belt-shaped sealing body 30 is used by being incorporated in, for example, an exhaust pipe spherical joint shown in FIG. That is, in the exhaust pipe spherical joint shown in FIG. 14, a flange 200 is erected on the outer peripheral surface of the upstream exhaust pipe 100 connected to the engine side, leaving the pipe end portion 101. The ball-shaped seal body 30 is fitted on a cylindrical inner surface 28 that defines the through-hole 27, and the ball-shaped seal body 30 is seated against the flange 200 at the annular end surface 31 on the large diameter side. The downstream side exhaust pipe 300 that is disposed opposite to the upstream side exhaust pipe 100 and connected to the muffler side is integrally provided with a concave spherical portion 302 and a flange portion 303 that is connected to the concave spherical portion 302. The provided enlarged diameter portion 301 is fixed, and the inner surface 304 of the concave spherical surface portion 302 is in sliding contact with the partially convex spherical outer surface 35 of the ball-shaped seal body 30.

  In the exhaust pipe spherical joint shown in FIG. 14, a pair of bolts 400 having one end fixed to the flange 200 and the other end inserted through the flange portion 303 of the enlarged diameter portion 301 and the enormous head and flange portion of the bolt 400. A spring force is always applied to the downstream side exhaust pipe 300 in the direction of the upstream side exhaust pipe 100 by the pair of coil springs 500 arranged between 303. Such an exhaust pipe spherical joint has a partially convex spherical outer surface 35 of the ball-shaped seal body 30 and an end of the downstream exhaust pipe 300 with respect to relative angular displacement occurring in the upper and downstream exhaust pipes 100 and 300. This is allowed by sliding contact with the inner surface 304 of the concave spherical surface portion 302 of the enlarged diameter portion 301 formed in the above.

  Next, the present invention will be described in detail based on examples. In addition, this invention is not limited to these Examples at all.

<Examples 1-3>
Using two austenitic stainless steel wires (SUS304) having a wire diameter of 0.28 mm as thin metal wires, a cylindrical braided wire mesh with a mesh size of 3 mm is produced, and this is passed between rollers to form a belt-like wire mesh. did. As the heat-resistant sheet material, an expanded graphite sheet having a thickness of 0.38 mm ("Nika Film (trade name)" manufactured by Nippon Carbon Co., Ltd.) was used. After the heat-resistant sheet material was wound in a spiral, it was placed inside the heat-resistant sheet material. A cylindrical base material in which the heat-resistant sheet material was placed on the outermost periphery by superposing the reinforcing materials and spirally wound was produced, and both end portions in the width direction of the heat-resistant sheet material were reinforced. It protrudes in the width direction of the material.

  A cylindrical braided wire net having a mesh size of 3 mm was produced using one metal thin wire similar to the above, and this was passed between rollers to form a belt-like wire mesh. A heat-resistant sheet material similar to the above was separately prepared, and the heat-resistant sheet material was inserted into the belt-shaped wire mesh. Prepare a heat-resistant sheet material similar to the above, and on one surface of the heat-resistant sheet material, an aqueous dispersion (solid content 60%) of PTFE (“Polyflon (trade name)” manufactured by Daikin Industries, Ltd.) as a fluorine resin. The graphite powder was used at a ratio of a: 2 parts by weight (Example 1), b: 5 parts by weight (Example 2), and c: 7 parts by weight (Example 3) with respect to 100 parts by weight of this aqueous dispersion. Dispersed PTFE composition (as solid content: a: graphite powder 3.2 wt%, PTFE 96.8 wt%, b: graphite powder 7.7 wt%, PTFE 92.3% wt, c: graphite powder 10.4 A coating layer of PTFE composition was formed by repeating the coating operation of applying an aqueous dispersion (by weight, PTFE 89.6% by weight) with a roller and drying it three times. Subsequently, this was baked for 10 minutes at a temperature of 340 ° C., which is equal to or higher than the melting point (327 ° C.) of PTFE, to form a coating layer of a PTFE composition having a thickness of 12 μm on one surface of the heat-resistant sheet material.

  A heat-resistant sheet material having a coating layer is superimposed on the belt-shaped wire mesh holding the heat-resistant material inside with the coating layer facing upward, and an outer layer forming member is produced by integrating these layers through rollers. did.

  On the outer peripheral surface of the cylindrical base material, the outer layer forming member was wound with the covering layer on the outer side to prepare a preliminary cylindrical molded body. This preliminary cylindrical molded body was inserted into the stepped core of the mold shown in FIG. 13, and the preliminary cylindrical molded body was positioned in the hollow portion of the mold.

A pre-cylindrical molded body positioned in the hollow portion of the mold is compression-molded with a pressure of 2 ton / cm ^{2 in} the core axial direction, and has a through hole in the central portion and has a cylindrical inner surface, a partially convex spherical surface, and a partially convex spherical surface. A spherical belt-shaped sealing body comprising a spherical belt-shaped substrate defined by an annular end surface on the large-diameter side and a small-diameter side of a spherical surface, and an outer layer integrally formed on a partially convex spherical surface of the spherical belt-shaped substrate was produced. .

  By this compression molding, the ball-shaped substrate is configured such that a heat-resistant material made of a heat-resistant sheet material and a reinforcing material made of a metal mesh are compressed and intertwined to have structural integrity, and a reinforcing material made of a compressed metal mesh And a heat-resistant material made of expanded graphite which is packed and integrated with the reinforcing material and compressed, and the outer layer is made of a heat-resistant material made of compressed expanded graphite and And a PTFE composition containing a graphite powder integrated with the reinforcing material and the heat-resistant material, and a portion exposed to the outside in the outer layer. The convex spherical outer surface becomes a smooth surface containing the calcined PTFE composition, and the cylindrical inner surface defining the through hole becomes a surface where the compressed heat-resistant material of the spherical base is exposed, and the partially convex spherical outer surface Large diameter side and small diameter side The annular end face, the portion protruding from the reinforcing member in the widthwise direction are exposed heat-resistant material which is attained by the bent and spread in the heat-resistant sheet member.

<Example 4>
A cylindrical base material was produced in the same manner as in the previous example. In the same manner as in the above example, a belt-like wire net having a heat resistant material inserted therein was produced. A heat-resistant material similar to that in the above examples was separately prepared, and an aqueous dispersion (60% solid content) of FEP (“Nephron FEP (trade name)” manufactured by Daikin Industries, Ltd.) as a fluorine resin was formed on one surface of the heat-resistant material. An aqueous dispersion of an FEP composition (graphite powder 7.7% by weight, FEP 92.3% by weight) containing 5 parts by weight of graphite powder dispersed in 100 parts by weight of this aqueous dispersion. The coating operation of coating John with a roller and drying was repeated three times to form a coating layer of the FEP composition. Subsequently, this was baked for 10 minutes at a temperature of 340 ° C., which is equal to or higher than the melting point (270 ° C.) of FEP, to form a coating layer of the baked FEP composition having a thickness of 12 μm on one surface of the heat-resistant sheet material. Thereafter, a spherical belt-like sealing body was produced in the same manner as in Example 1.

  The spherical belt-shaped substrate of this material is configured such that a heat-resistant material made of a heat-resistant sheet material and a reinforcing material made of a wire mesh are compressed and entangled with each other to have structural integrity, and a reinforcing material made of a compressed wire mesh, It has a heat-resistant material made of expanded graphite that is compressed by being mixed and integrated with this reinforcing material, and the outer layer is made of compressed heat-resistant graphite and this heat-resistant material. A partially convex spherical surface exposed to the outside in the outer layer, comprising a reinforcing material made of a wire mesh mixed with the material, and an FEP composition containing graphite powder integrated with the reinforcing material and the heat-resistant material. The outer surface is a smooth surface containing the fired FEP composition, and the cylindrical inner surface that defines the through-hole is the surface where the compressed heat-resistant material of the spherical base is exposed, and the large-diameter side of the partially convex spherical outer surface And on the annular end face on the small diameter side Portion protruding from the reinforcing member in the widthwise direction are exposed heat-resistant material which is attained by the bent and spread in the heat-resistant sheet member.

<Example 5>
A cylindrical base material was produced in the same manner as in the previous example. In the same manner as in the above example, a belt-like wire net having a heat resistant material inserted therein was produced. A heat-resistant material similar to that in the above examples was separately prepared, and an aqueous dispersion (60% solid content) of PFA (“Neofluon PFA (trade name)” manufactured by Daikin Industries, Ltd.) as a fluorine resin was formed on one surface of the heat-resistant material. The aqueous dispersion in which graphite powder is dispersed and contained at a ratio of 5 parts by weight with respect to 100 parts by weight of this aqueous dispersion (7.7% by weight of graphite powder and 92.3% by weight of PFA as a solid content) is applied with a roller. Then, the coating operation of drying was repeated 3 times to form a coating layer of the PFA composition. Next, this was baked for 10 minutes at a temperature of 300 ° C., which is equal to or higher than the melting point (280 ° C.) of PFA, to form a baked PFA composition coating layer having a thickness of 12 μm on one surface of the heat-resistant sheet material. Thereafter, a spherical belt-like sealing body was produced in the same manner as in Example 1.

  The spherical belt-shaped substrate of this material is configured such that a heat-resistant material made of a heat-resistant sheet material and a reinforcing material made of a wire mesh are compressed and entangled with each other to have structural integrity, and a reinforcing material made of a compressed wire mesh, It has a heat-resistant material made of expanded graphite that is compressed by being mixed and integrated with this reinforcing material, and the outer layer is made of compressed heat-resistant graphite and this heat-resistant material. It has a reinforcing material composed of a wire mesh that is mixed and integrated with the material, and a PFA composition containing graphite powder integrated with the reinforcing material and the heat-resistant material. The outer surface is a smooth surface containing the calcined PFA composition, the cylindrical inner surface defining the through-hole is the surface where the compressed heat-resistant material of the spherical base is exposed, and the large-diameter side of the partially convex spherical outer surface And on the annular end face on the small diameter side Portion protruding from the reinforcing member in the widthwise direction are exposed heat-resistant material which is attained by the bent and spread in the heat-resistant sheet member.

<Comparative example>
A cylindrical base material was produced in the same manner as in the previous example. In the same manner as in the above example, a belt-like wire net having a heat resistant material inserted therein was produced. A heat-resistant material similar to that in the above example was separately prepared, and an aqueous dispersion of PTFE (“Polyflon (trade name)” manufactured by Daikin Industries, Ltd.) as a fluororesin on one surface of the heat-resistant material (solid content: 60% by weight) The PTFE coating layer was formed by repeating the coating operation of coating the aqueous dispersion with a roller and drying it three times. Subsequently, this was baked for 10 minutes at a temperature of 340 ° C., which is equal to or higher than the melting point (327 ° C.) of PTFE, to form a baked PTFE coating layer having a thickness of 12 μm on one surface of the heat-resistant sheet material.

  The spherical belt-shaped substrate of this material is configured such that a heat-resistant material made of a heat-resistant sheet material and a reinforcing material made of a wire mesh are compressed and entangled with each other to have structural integrity, and a reinforcing material made of a compressed wire mesh, It has a heat-resistant material made of expanded graphite that is compressed by being mixed and integrated with this reinforcing material, and the outer layer is made of compressed heat-resistant graphite and this heat-resistant material. It has a reinforcing material made of a wire mesh mixed and integrated with the material, and PTFE integrated with the reinforcing material and the heat-resistant material, and the partially convex spherical outer surface exposed to the outside in the outer layer is a baked PTFE The cylindrical inner surface defining the through-hole is a surface where the compressed heat-resistant material of the spherical base is exposed, and the heat-resistant sheet is provided on the large-diameter and small-diameter annular end surfaces of the partially convex spherical outer surface. Width from reinforcement in the material Portion protruding in direction is obtained by being bent to and spread the heat-resistant material is exposed.

  Next, the ball-shaped seal body obtained in each of the above-described examples and comparative examples is incorporated into the exhaust pipe spherical joint shown in FIG. 14, and the sliding between the partially convex spherical outer surface of the outer layer of the ball-shaped seal body and the surface of the mating member is performed. The results of testing for the presence or absence of sliding friction noise (abnormal friction noise) during movement will be described.

<Test method>
The exhaust pipe joint shown in FIG. 14 is used, and as a test mode, the swing angle is a minute swing angle (a minute swing angle generated during constant speed running) and a general swing angle (a swing angle generated during acceleration / deceleration). 14), the oscillation frequency is set to be constant at 10 Hz and vibration is performed at each oscillation angle, and the outer surface temperature of the concave spherical portion 302 shown in FIG. 14 is 200 ° C. to 550 ° C. The temperature was raised every 50 ° C. until the temperature was reached, and the test of rocking for a certain period of time when each measurement temperature was reached was performed as 3 cycles, and the presence or absence of abnormal frictional noise at each measurement temperature was measured.

Judgment of the occurrence of abnormal frictional noise was made according to the following criteria.
Evaluation symbol: A ··· No frictional abnormal sound.
Evaluation symbol: B: A frictional abnormal sound can be heard with the ear close to the test piece.
Evaluation symbol: C ··········································································
Evaluation symbol: D ... Anything that can be identified as an abnormal frictional sound at a fixed position.
In the above evaluation symbol, it was determined that the spherical belt-shaped seal body indicated by the evaluation symbol C or D was difficult to use for the exhaust pipe spherical joint.

Tables 1 to 6 show the results of testing for the presence or absence of abnormal frictional noise with respect to the above-described test conditions for the ball-shaped seals obtained in the above Examples and Comparative Examples. Table 1 shows Example 1, Table 2 shows Example 2, Table 3 shows Example 3, Table 4 shows Example 4, Table 5 shows Example 5, and Table 6 shows the test results of Comparative Examples.

  From the test results shown in Table 1 to Table 6, in the ball-shaped seal bodies of Examples 1 to 5, the evaluation symbol for the presence or absence of abnormal frictional noise is A or B throughout the test time, and the evaluation symbol is C or D. It can be seen that no abnormal friction noise was found. On the other hand, in the spherical belt-shaped sealing body of the comparative example, the evaluation symbol of abnormal frictional sound indicates C or D, and generation of abnormal frictional sound that is difficult to use for the exhaust pipe spherical joint was recognized. It was observed that a graphite lubricating film of a fluororesin composition was formed on the surface of the counterpart material in these examples after completion of the test (the inner surface 304 of the concave spherical surface portion 302). In this way, the spherical band-shaped sealing body of the example did not generate the abnormal frictional sound of the evaluation symbol C or D because the graphite lubricating film was formed on the surface of the counterpart material, and the coating layer of the fluorine resin composition Even when the heat dissipation material disappears at a temperature exceeding 450 ° C. and the heat-resistant material is exposed on the outer surface of the partially convex spherical surface, the heat-resistant material and the mating material surface shift to sliding friction via a graphite lubricating film, Since direct sliding friction between the material and the mating material surface was avoided, it is presumed that as a result, the abnormal friction sound whose evaluation symbol indicates C or D did not occur.

  From the above test results, the spherical belt-shaped sealing body of the example has an outer layer having a baked fluororesin composition containing graphite powder, so that the exhaust pipe spherical joint in sliding friction with the counterpart material It does not cause abnormal frictional sounds that are difficult to use.

It is a longitudinal cross-sectional view of the spherical belt shaped sealing body manufactured in an example of embodiment of this invention. It is a partially expanded sectional view of the spherical belt shaped sealing body shown in FIG. It is explanatory drawing of the formation method of the reinforcing material in the manufacturing process of the spherical belt shaped sealing body of this invention. It is a perspective view of the heat-resistant material in the manufacturing process of the spherical belt shaped sealing body of the present invention. It is a perspective view of the polymer in the manufacturing process of the spherical belt shaped sealing body of this invention. It is a top view of the cylindrical preform | base_material in the manufacturing process of the spherical belt shaped sealing body of this invention. It is a longitudinal cross-sectional view of the cylindrical base material shown in FIG. It is a perspective view of the heat-resistant material in the manufacturing process of the spherical belt shaped sealing body of the present invention. It is explanatory drawing which shows the state which piled up the heat-resistant sheet material which formed the coating layer while inserting a heat-resistant material in the strip | belt-shaped metal mesh in the manufacturing process of the spherical belt-shaped sealing body of this invention. It is a longitudinal cross-sectional view of the heat-resistant sheet in which the coating layer in the manufacturing process of the spherical belt shaped sealing body of this invention was formed. It is explanatory drawing of the formation method of the outer layer formation member in the manufacturing process of the spherical belt shaped sealing body of this invention. It is a top view of the preliminary | backup cylindrical molded object in the manufacturing process of the spherical belt shaped sealing body of this invention. It is a longitudinal cross-sectional view which shows the state which inserted the preliminary | backup cylindrical molded object in the metal mold | die in the manufacturing process of the spherical belt shaped sealing body of this invention. It is a longitudinal cross-sectional view of the exhaust pipe spherical joint incorporating the spherical belt shaped sealing body of the present invention. It is explanatory drawing of the exhaust system of an engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical wire mesh 4 Strip | belt-shaped wire mesh 5 Reinforcement material 6 Heat-resistant sheet material 12 Polymer 13 Cylindrical base material 14 Coating layer 17 Outer layer forming member 18 Preliminary cylindrical molded body 26 Mold 30 Spherical belt-shaped seal body

Claims (3)

A spherical band base defined by a cylindrical inner surface, a partially convex spherical surface, and annular end surfaces on the large diameter side and the small diameter side of the partial convex spherical surface, and a partially convex spherical surface of the spherical band base body are integrally formed. And an outer layer having a partially convex spherical outer surface exposed to the outside, and in particular a spherical belt-shaped sealing body used for an exhaust pipe joint, wherein the spherical belt-shaped substrate includes a reinforcing material made of a compressed wire mesh, And a heat-resistant material made of expanded graphite that is packed together and integrated with the reinforcing material, and the outer layer includes a heat-resistant material made of expanded graphite and the heat-resistant material. A reinforcing material composed of a metal mesh mixed and integrated with the material, and integrated with the heat-resistant material and the reinforcing material, and composed of 1 to 15% by weight of graphite powder and the remaining fluororesin, and having a melting point higher than that of the fluororesin A fluororesin composition fired at a temperature The partially convex spherical outer surface exposed to the outside of the outer layer is made of the above-mentioned 1-15% by weight of graphite powder and the remaining fluororesin and is baked at a temperature equal to or higher than the melting point of the fluororesin. It has a smooth surface, and the fluororesin is a spherical band seal selected from a tetrafluoroethylene resin, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and a tetrafluoroethylene-hexafluoropropylene copolymer. body. The spherical belt-shaped sealing body according to claim 1, wherein the heat-resistant material made of expanded graphite of the spherical belt-shaped substrate is exposed on the inner surface of the cylinder. The spherical belt-shaped sealing body according to claim 1 or 2, wherein a reinforcing material made of a metal mesh of the spherical belt-shaped substrate is exposed on the inner surface of the cylinder.

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