JP2005127391A - Spherical belt-like seal material, and exhaust pipe joint device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spherical belt-like seal material that never generates abnormal noises due to stick-slip and the like or gives discomfort to a driver even when torsional and shearing forces are inputted to an exhaust pipe connected with a manifold and an exhaust pipe joint device of an automobile using it. <P>SOLUTION: This spherical belt-like seal material 28 comprises a seal body 27 having a projecting partially spherical outer face 24, and large-diameter and small-diameter side annular end faces 25 and 26 of the projecting partially spherical outer face 24; and a heat-expandable annular coating layer 29 made of acid-treated graphite and integrally formed on a cylindrical inner face 23 of the seal body 27. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a ball-shaped seal body and an exhaust pipe joint device for an automobile using the same.

Japanese Patent Publication No.58-21144

  The exhaust gas of an automobile engine is led from an engine to an exhaust pipe disposed on a body frame or the like and discharged into the atmosphere. This exhaust pipe is subjected to bending stress due to torque reaction force and inertial force of the engine. . In particular, in the case of a front-wheel drive horizontal engine (FF vehicle), this bending stress is considerably larger than that of a vertical engine. Accordingly, there is a risk that engine vibrations are transmitted to the vehicle interior through the exhaust pipe suspension, or cause noise, as well as problems such as fatigue breakage of the exhaust pipe. In order to solve such a problem, conventionally, means such as disposing an exhaust pipe joint device having a spherical pipe joint (spherical seal body) at a predetermined position of the exhaust pipe to absorb stress is taken. (Patent Document 1).

  In many cases, such a spherical pipe joint is slidably in contact with the concave spherical inner surface of the flange member fixed to the end of the downstream exhaust pipe at the convex spherical outer surface of the ball-shaped seal body. The inner surface thereof is fitted to the outer peripheral surface of the pipe end portion of the upstream side exhaust pipe, and the relative sliding of the outer surface of the convex spherical surface of the ball-shaped sealing body with respect to the inner surface of the concave spherical surface of the flange member is used. To absorb the stress.

  By the way, in a front-wheel drive horizontally mounted engine (FF vehicle), an exhaust pipe (manifold) is provided on the rear side of the engine in recent years. Therefore, the exhaust pipe connected to the manifold has a shear direction (perpendicular to the pipe axis direction of the exhaust pipe). In addition to the force in the direction of rotation), in particular, a force in the twisting direction (rotation direction around the pipe axis of the exhaust pipe) is greatly applied, and this force is also input to the exhaust pipe joint device.

  When a large torsional force is applied to the exhaust pipe joint device, stick slip occurs between the inner peripheral surface of the spherical pipe joints fitted to each other and the pipe end of the upstream side exhaust pipe, resulting from the stick slip. An abnormal sound is generated, which causes discomfort to the driver and passenger of the car.

  The present invention has been made in view of the above-described points, and the object of the present invention is due to stick slip or the like even when forces in the twisting direction and shearing direction are input to the exhaust pipe connected to the manifold. It is an object of the present invention to provide a ball-shaped seal body that does not generate an abnormal noise and does not give a driver unpleasant feeling and an automobile exhaust pipe joint device using the same.

  A spherical belt-like seal body according to a first aspect of the present invention includes a seal body having a cylindrical inner surface, a partially convex spherical outer surface, and large and small diameter annular end surfaces of the partially convex spherical outer surface, and the seal body And a thermally expandable annular coating layer integrally formed on the inner surface of the cylinder.

  According to the ball-shaped seal body of the first aspect, since the cylindrical inner surface of the seal body is provided with the annular coating layer that can be thermally expanded, the ball-band seal body including the seal body is used as the seal. Fits to the outer peripheral surface of the pipe end of the upstream exhaust pipe with the inner peripheral surface of the thermally expandable annular coating layer integrally formed on the cylindrical inner surface of the main body, and the annular end surface on the large diameter side of the seal body In contact with the flange fixed to the upstream exhaust pipe, and slidably contact the partially concave spherical surface of the seal seat member fixed to the downstream exhaust pipe on the outer surface of the partially convex spherical surface of the seal body, and elastically connected When used in an exhaust pipe joint device in which the upstream exhaust pipe and the downstream exhaust pipe are elastically connected to each other so that they can be displaced relative to each other by means, the heat of the exhaust gas flowing in the exhaust pipe is integrated with the cylindrical inner surface of the seal body. A thermally expandable annular coating layer The spherical end seal body and the outer peripheral surface of the pipe end portion of the upstream side exhaust pipe are integrated so as to tighten the pipe end portion of the side exhaust pipe, so that the upstream side connected to the manifold Even when a twisting direction (rotation direction) force is input to the exhaust pipe, the ball-shaped seal body can be reliably rotated together with the rotation of the upstream exhaust pipe, and the inner peripheral surface and the upstream side of the annular coating layer There is no sliding between the outer peripheral surface of the exhaust pipe and between the annular end surface on the large diameter side of the seal body and the flange, and there is no occurrence of abnormal friction noise due to stick-slip or the like here, It can be set as a ball-shaped seal body that does not give the driver unpleasant feeling.

  In the present invention, the heat-expandable annular coating layer contains acid-treated graphite, as in the preferred embodiment, as in the ball-shaped seal body of the second embodiment, and in a more preferred example, the sphere of the third embodiment. It contains acid-treated graphite before expansion treatment like a band-shaped seal body, and in a more preferred example, it contains compressed acid-treated graphite before expansion treatment like the spherical band-shaped seal body of the fourth aspect. In an even more preferred example, acid-treated graphite formed by compressing the acid-treated graphite powder before the expansion treatment is contained, like the ball-shaped seal body of the fifth aspect.

  In the present invention, the seal main body is formed by compression-molding a heat-resistant material containing expanded graphite and a reinforcing material made of a wire mesh, like the ball-shaped seal body of the sixth aspect in a preferred example, A heat-resistant material is filled in a gap between reinforcing members made of a wire mesh.

  An exhaust pipe joint device according to a first aspect of the present invention includes an upstream exhaust pipe, a downstream exhaust pipe having an end face opposed to the end face of the upstream exhaust pipe, leaving a gap, and an upstream exhaust pipe The flange fixed to the outer peripheral surface of the pipe end, the seal seat member fixed to the pipe end of the downstream exhaust pipe and having a partially concave spherical surface, the upstream exhaust pipe and the downstream exhaust pipe It comprises elastic coupling means that are elastically coupled to each other so as to be angularly displaceable, and a spherical belt-like sealing body according to any one of the first to sixth aspects, wherein the spherical belt-like sealing body is an annular coating layer Is fitted to the outer peripheral surface of the pipe end of the upstream exhaust pipe at the inner peripheral surface of the seal body, is in contact with the flange at the annular end surface on the large diameter side of the seal body, and is on the partially convex spherical outer surface of the seal body. The seal seat member is slidably contacted with the partially concave spherical surface.

  According to the exhaust pipe joint device of the first aspect, the ball-shaped seal body slides on the partially concave spherical surface of the seal seat member fixed to the pipe end of the downstream side exhaust pipe on the partially convex spherical outer surface of the seal body. As a result of the free contact, the relative angular displacement generated between the upstream exhaust pipe and the downstream exhaust pipe is allowed by sliding between the partially convex spherical outer surface of the seal body and the partially concave spherical surface of the seal seat member. On the other hand, the seal between the upstream side exhaust pipe and the downstream side exhaust pipe is not only in close contact with the partially convex spherical outer surface of the seal body and the partially concave spherical surface of the seal seat member, but also within the annular coating layer. This is performed by fitting the peripheral surface with the outer peripheral surface of the pipe end portion of the upstream side exhaust pipe and contacting the annular end surface on the large diameter side of the seal body with the flange.

  According to the exhaust pipe joint device of the first aspect, the heat-expandable annular coating layer integrally formed on the cylindrical inner surface of the seal body is heated upstream by the heat of the exhaust gas flowing in the exhaust pipe. The pipe end of the pipe expands so as to be tightened, and the spherical belt-like seal body and the outer peripheral surface of the pipe end of the upstream exhaust pipe are integrated. As a result, the upstream exhaust pipe connected to the manifold is twisted. Even when a force in the (rotational direction) is input, the ball-shaped seal body can be reliably rotated together with the rotation of the upstream exhaust pipe, and the cylindrical inner peripheral surface of the annular coating layer and the upstream exhaust pipe No sliding between the outer peripheral surface of the pipe end and the annular end surface on the large-diameter side of the seal body and the flange, and abnormal friction noise caused by stick-slip or the like here can be generated. No discomfort to the driver It may be a tracheal coupling device.

  The example of the manufacturing method of the spherical belt shaped sealing body which concerns on this invention is demonstrated. First, a cylindrical wire mesh formed by knitting a thin metal wire is prepared, and this cylindrical wire mesh is passed between a pair of rollers to form a belt-like wire mesh, which is then cut to a predetermined length and used as a reinforcing material. To do. As a heat-resistant material, an expanded graphite sheet having a predetermined width and length and made of expanded graphite is prepared, and an acid-treated graphite powder and an adhesive such as polyvinyl alcohol (on the surface of one end of the expanded graphite sheet ( A paste-like mixture with PVA) is coated for a predetermined length and then dried to form a coating forming layer made of the acid-treated graphite powder.

  In the present invention, as the acid-treated graphite powder, one produced by the following production method is preferably used. While stirring concentrated sulfuric acid having a concentration of 98%, a predetermined amount of a 60% aqueous solution of hydrogen peroxide as an oxidizing agent was added to prepare a reaction solution, and a predetermined amount of scaly natural graphite powder was added to the reaction solution for a predetermined time. Perform the reaction. After the reaction, suction filtration is performed to separate the acid-treated graphite powder, and the washing operation of stirring the acid-treated graphite powder with water for a predetermined time and suction filtering is repeated to sufficiently remove the sulfuric acid content from the acid-treated graphite powder. Next, the acid-treated graphite powder from which the sulfuric acid content has been sufficiently removed is dried in a drying furnace to obtain an acid-treated graphite powder. The acid-treated graphite powder thus obtained has the property of expanding and expanding between graphite layers under the influence of heat.

A reinforcing material made of a belt-shaped wire mesh and an expanded graphite sheet are overlapped, and the coating forming layer made of the acid-treated graphite powder is turned inside, and the expanded graphite sheet is positioned on the outermost periphery, and is wound into a cylindrical shape. Make the material. Next, a cylindrical wall surface, a partially concave spherical wall surface continuous to the cylindrical wall surface and a through hole continuous to the partial concave spherical wall surface are provided on the inner surface, and a hollow core portion and a hollow cylindrical portion are formed inside by inserting a stepped core into the through hole. Prepare a mold with a hollow part composed of a series of spherical belt-shaped hollow parts, insert the cylindrical base material positioned in the hollow part of the mold by inserting it into the stepped core of the mold, and punch the core shaft Compressive molding is performed at a pressure of 1 to 3 ton / cm ^{2 in} the direction, whereby the heat-resistant material made of expanded graphite and the reinforcing material made of wire mesh are compressed, and the heat-resistant material is filled in the mesh of the reinforcing material made of wire mesh. A spherical belt-like seal body is produced. Such a spherical belt-shaped seal body is integrally formed with a cylindrical inner surface, a partially convex spherical outer surface, a partially convex spherical surface of a small-diameter side and a large-diameter annular end surface, and a cylindrical inner surface of the seal body. And a thermally expandable annular coating layer made of an acid-treated graphite powder before being expanded and compressed.

  According to the present invention, even when a force in the torsional direction and shearing direction is input to the exhaust pipe connected to the manifold, an abnormal noise caused by stick-slip or the like is not generated, which is inconvenient for the driver and passenger. It is possible to provide a ball-shaped seal body that does not give a pleasant feeling and an exhaust pipe joint device for an automobile using the same.

  Next, the present invention and its embodiments will be described in more detail with reference to the examples shown in the drawings. The present invention is not limited to this example.

<About acid-treated graphite powder>
While stirring 300 parts by weight of concentrated sulfuric acid having a concentration of 98%, 5 parts by weight of a 60% aqueous solution of hydrogen peroxide is added as an oxidizing agent, and this is used as a reaction solution. The reaction solution is cooled and maintained at a temperature of 10 ° C., 100 parts by weight of scaly natural graphite powder having a particle size of 30 to 80 mesh is added, and the reaction is performed for 30 minutes. After the reaction, the acid-treated graphite powder is separated by suction filtration, and the washing operation of stirring the acid-treated graphite powder with 300 parts by weight of water for 10 minutes and suction-filtering is repeated twice. Is removed sufficiently. Next, the acid-treated graphite powder from which sulfuric acid has been sufficiently removed is dried in a drying furnace maintained at a temperature of 110 ° C. for 3 hours to obtain an acid-treated graphite powder.

<About heat-resistant materials>
The acid-treated graphite powder is prepared separately, and the acid-treated graphite powder before the expansion treatment is heated (expanded) at a temperature of 950 to 1200 ° C. for 1 to 10 seconds to generate a decomposition gas, The graphite layer is expanded to form expanded graphite particles (expansion magnification: 200 to 300 times). The expanded graphite particles are roll-formed with a twin roller apparatus to produce an expanded graphite sheet having a desired thickness, and the expanded graphite sheet is used as a heat-resistant material.

<About reinforcing material>
The reinforcing material is austenitic SUS304, SUS316, ferritic SUS430 or the like, iron-based (JIS-G-3532) or galvanized iron wire (JIS-G-3547), or copper-copper-nickel. A wire mesh formed by weaving or knitting one or more fine metal wires made of alloy (white copper) wire, copper-nickel-zinc alloy (yoh white) wire, brass wire or beryllium copper wire. used. The wire diameter of the fine metal wire forming the wire mesh is preferably about 0.10 to 0.32 mm, and the wire mesh of about 3 to 6 mm is preferably used.

  Next, a method for manufacturing a spherical belt-shaped seal body made of the above-described constituent materials will be described with reference to the drawings.

  (First Step) As shown in FIG. 2, a strip metal mesh 4 having a predetermined width D is produced by passing a cylindrical metal mesh 1 formed by knitting a thin metal wire into a cylindrical shape between rollers 2 and 3. A reinforcing material 5 is prepared by cutting the wire into a predetermined length L.

  (Second Step) As shown in FIG. 3, the width d of the reinforcing material 5 is 1.10 × D to 2.10 × D and the width d of the reinforcing material 5 is 1 A heat-resistant material (expanded graphite sheet) 6 cut to have a length l of 30 × L to 2.70 × L is prepared.

  (Third step) Using polyvinyl alcohol (PVA) as an adhesive, the adhesive and acid-treated graphite powder are mixed to prepare a paste-like mixture.

  (Fourth Step) As shown in FIG. 4, the surface of one end of the heat-resistant material 6 is coated with a paste-like mixture for a predetermined length using a spatula and dried to coat the mixture. The formation layer 7 is formed.

  (Fifth step) The heat-resistant material 6 is entirely exposed on the end face 25 on the large diameter side which is an annular end face on at least one end edge side in the axial direction of the outer surface 24 of the partially convex spherical surface in a spherical belt-like seal body 28 to be described later. As shown in FIG. 5, 0.1 × D at the maximum from at least one end edge 8 in the width direction of the reinforcing member 5 which becomes the end surface 25 on the large diameter side of the outer surface 24 having a partially convex spherical shape. Of the reinforcing material 5 in which the heat-resistant material 6 protrudes in the width direction by 0.8 × D from the edge 8 and the protrusion amount δ1 in the width direction of the heat-resistant material 6 from the end edge 8 is on the small diameter end surface side of the outer surface of the partially convex spherical surface. The amount of protrusion δ2 from the other end edge 9 in the width direction is set to be larger, and from the one end edge 10 in the length direction of the reinforcing member 5 is 0.30 × L to 1.70 × L at the maximum. While the heat-resistant material 6 protrudes in the length direction, the other edge 11 in the length direction of the reinforcing material 5 and the Forming the coating so that the edge 12 in the length direction of the heat-resistant material 6 corresponding to the edge 11 is substantially matched, and the width direction and the length direction of the reinforcing material 5 and the heat-resistant material 6 are matched. The polymer 13 is obtained by superimposing the reinforcing material 5 on the back surface of the heat-resistant material 6 opposite to the surface on which the layer 7 is formed.

  (Sixth Step) The polymer 13 is spirally wound with the coating forming layer 7 inside as shown in FIG. 6 and wound so that the heat-resistant material 6 is increased once, over the entire circumference on the inner circumference side. Thus, the coating forming layer 7 forms a cylindrical base material 14 in which the heat-resistant material 6 is exposed over the entire circumference on the outer peripheral side. As the heat-resistant material 6, 1.30 × L to 2. with respect to the length L of the reinforcing material 5 so that the number of windings of the heat-resistant material 6 in the cylindrical base material 14 is larger than the number of windings of the reinforcing material 5. Those having a length l of 70 × L are prepared in advance. In the cylindrical base material 14, as shown in FIG. 7, the heat-resistant material 6 protrudes from the one edge 8 of the reinforcing material 5 by δ1 in the width direction on one edge side in the width direction. 6 extends beyond the other end edge 9 of the reinforcing member 5 in the width direction on the other end edge side in the width direction 6.

  (Seventh step) A cylindrical wall surface 15, a partially concave spherical wall surface 16 connected to the cylindrical wall surface 15, and a through hole 17 connected to the partially concave spherical wall surface 16 are provided on the inner surface, and a stepped core 18 is inserted into the through hole 17. A mold 21 as shown in FIG. 8 in which a hollow portion comprising a hollow cylindrical portion 19 and a spherical belt-shaped hollow portion 20 connected to the hollow cylindrical portion 19 is formed is prepared, and a stepped core 18 of the mold 21 is prepared. The cylindrical base material 14 is inserted into.

A cylindrical base material 14 positioned in a hollow portion composed of a hollow cylindrical portion 19 and a spherical belt-shaped hollow portion 20 of a mold 21 is compression-molded at a pressure of 1 to 3 ton / cm ^{2 in} the core axial direction, and is shown in FIG. A seal body 27 having a cylindrical inner surface 23, a partially convex spherical outer surface 24, and annular end surfaces 25 and 26 on the large-diameter side and small-diameter side of the partially convex spherical outer surface 24; A spherical belt-shaped seal having a thermally expandable annular coating layer 29 made of acid-treated graphite integrally formed on a cylindrical inner surface 23 and having a through-hole 22 in the central portion defined by the inner peripheral surface of the coating layer 29 The body 28 is produced.

  By this compression molding, the ball-shaped seal body 28 is configured such that the heat-resistant material 6 and the reinforcing material 5 made of a wire mesh are compressed and entangled with each other to have structural integrity, and the reinforcing material made of a compressed wire mesh. 5 and a heat-resistant material 6 made of expanded graphite which is packed together and integrated with the reinforcing material 5 and is compressed. A thermally expandable annular coating layer 29 made of the acid-treated graphite before the expansion treatment is exposed to the outside through the through holes 22.

  In the spherical belt-shaped sealing body 28 shown in FIG. 1 manufactured by the above-described method, the heat-resistant material 6 is intertwined with the reinforcing material 5 made of a wire mesh that forms the internal structure, and is integrated with the outer surface 24 having a partially convex spherical shape. Is formed on the smooth surface of the heat-resistant material 6 made of expanded graphite, and the annular end surface 25 on the large-diameter side and the end surface 26 on the small-diameter side of the partially convex spherical outer surface 24 extend from the reinforcing material 5 in the width direction. The protruding heat-resistant material 6 is bent and spread on the large-diameter annular end surface 25 and the small-diameter end surface 26 of the partially convex spherical outer surface 24 and is covered with the heat-resistant material 6 made of expanded graphite. ing.

  Such a ball-shaped seal body 28 is used in an exhaust pipe joint device 30 as shown in FIG. The exhaust pipe joint device 30 includes an upstream exhaust pipe 31 connected to the engine side, and a downstream side connected to the atmosphere side having an end face 34 opposed to the end face 32 of the upstream exhaust pipe 31 and leaving a gap 33 therebetween. The exhaust pipe 35, the flange 37 fixed to the outer peripheral surface of the pipe end portion 36 of the upstream side exhaust pipe 31 by welding or the like, and the outer peripheral surface of the pipe end portion 38 of the downstream side exhaust pipe 35 to be fixed by welding or the like. In addition, a seal seat member 40 having a partially concave spherical surface 39, elastic connecting means 41 for elastically connecting the upstream side exhaust pipe 31 and the downstream side exhaust pipe 35 to each other so as to be relatively angularly displaceable, a ball-shaped seal body 28, It has.

  The spherical belt-like seal body 28 is fitted to the outer peripheral surface of the pipe end portion 36 of the upstream exhaust pipe 31 with a thermally expandable annular coating layer 29 made of acid-treated graphite, and on the large diameter side of the seal body 27. The annular end surface 25 is in contact with the side surface 51 substantially perpendicular to the axial direction X of the flange 37, and the outer surface 24 of the partially convex spherical surface of the seal body 27 is slidable on the partially concave spherical surface 39 of the seal seat member 40. Is touching.

  The elastic connecting means 41 has a pair of bolts 43 arranged at one end fixed to the flange 37 and the other end extending integrally from the seal seat member 40 and an outer peripheral surface of the bolt 43. And a pair of coil springs 44 disposed between the head portion of the bolt 43 and the flange portion 42, and the upstream side exhaust pipe 31 and the downstream side exhaust pipe 35 are provided with such elastic connecting means. 41, the downstream exhaust pipe 35 is always biased by the spring force of the pair of coil springs 44 in the direction of the upstream exhaust pipe 31.

  In the exhaust pipe joint device 30, the relative angular displacement generated between the upstream side exhaust pipe 31 and the downstream side exhaust pipe 35 is caused by the partially convex spherical outer surface 24 of the spherical belt-shaped seal body 28 and the partially concave spherical surface of the seal seat member 40. Allowed to slide between 39.

  According to the exhaust pipe joint device 30 described above, the spherical belt-like seal body 28 is formed on the partially concave spherical surface 39 of the seal seat member 40 fixed to the pipe end portion 38 of the downstream side exhaust pipe 35 by the partially convex spherical outer surface 24. As a result of the slidable contact, the relative angular displacement generated between the upstream exhaust pipe 31 and the downstream exhaust pipe 35 is caused by the partially convex spherical outer surface 24 of the spherical belt-shaped seal body 28 and the partial concave of the seal seat member 40. The outer seal 24 between the upstream exhaust pipe 31 and the downstream exhaust pipe 35 is allowed to slide between the spherical surface 39 and the portion of the seal convex member 27 and the seal seat member 40. In addition to intimate contact with the concave spherical surface 39, fitting between the annular coating layer 29 formed integrally with the cylindrical inner surface 23 of the seal body 27 and the pipe end portion 36 of the upstream exhaust pipe 31 and the seal body 27 Annular end face 25 on the large diameter side and flange It will be done by contact with 7 side 51.

  According to the exhaust pipe joint device 30, in the ball-shaped seal body 28, the thermally expandable annular coating layer 29 formed integrally with the cylindrical inner surface 23 is exhausted by the heat of the exhaust gas flowing in the exhaust pipe. As a result of expansion so as to tighten the outer peripheral surface of the pipe, even when a force in the twisting direction (rotation direction) is input to the upstream exhaust pipe 31 connected to the manifold, the ball-shaped seal body 28 is connected to the upstream exhaust pipe 31. , Between the cylindrical inner surface of the coating layer 29 and the outer peripheral surface of the pipe end portion 36 of the upstream exhaust pipe 31 and the annular end surface 25 and the flange 37 on the large diameter side of the seal body 27. No sliding is generated during this time, no abnormal frictional noise caused by stick-slip or the like here is generated, and no uncomfortable feeling is given to the driver.

It is a longitudinal cross-sectional view which shows the spherical belt shaped sealing body of this invention. 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 heat-resistant material and the coating forming layer 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 preform | base_material shown in FIG. It is a longitudinal cross-sectional view which shows the state which inserted the cylindrical preform | base_material 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 joint apparatus incorporating the spherical belt shaped sealing body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Reinforcement material 6 Heat-resistant material 7 Coating formation layer 14 Cylindrical base material 21 Mold 27 Seal body 28 Spherical belt-shaped sealing body

Claims (7)

  A seal body having a cylindrical inner surface, a partially convex spherical outer surface, and annular end surfaces on the large diameter side and small diameter side of the partially convex spherical outer surface, and a thermally expandable integrally formed on the cylindrical inner surface of the seal body A spherical belt-shaped sealing body comprising an annular coating layer.   The ball-shaped seal body according to claim 1, wherein the thermally expandable annular coating layer includes acid-treated graphite.   The ball-shaped seal body according to claim 1 or 2, wherein the thermally expandable annular coating layer contains acid-treated graphite before expansion treatment.   4. The spherical belt-shaped sealing body according to claim 1, wherein the thermally expandable annular coating layer includes compressed acid-treated graphite before expansion treatment. 5.   5. The spherical belt-shaped sealing body according to claim 1, wherein the thermally expandable annular coating layer includes acid-treated graphite obtained by compressing acid-treated graphite powder before expansion treatment. 6.   The seal body is formed by compression-molding a heat-resistant material containing expanded graphite and a reinforcing material made of a wire mesh, and the heat-resistant material is filled in a gap between the reinforcing materials made of the wire mesh. The spherical belt-like seal body according to item.   An upstream exhaust pipe, a downstream exhaust pipe having an end face facing the end face of the upstream exhaust pipe, leaving a gap, a flange fixed to the outer peripheral surface of the pipe end of the upstream exhaust pipe, and a downstream A seal seat fixed to the pipe end of the side exhaust pipe and having a partially concave spherical surface, and an elastic connecting means for elastically connecting the upstream side exhaust pipe and the downstream side exhaust pipe to each other so as to be relatively angularly displaceable. The spherical belt-shaped seal body according to any one of claims 1 to 6, wherein the spherical belt-shaped seal body is an outer periphery of the pipe end portion of the upstream side exhaust pipe on the inner peripheral surface of the annular coating layer. Is fitted to the surface, is in contact with the flange at the annular end surface on the large diameter side of the seal body, and is slidably contacted with the partially concave spherical surface of the seal seat member at the partially convex spherical outer surface of the seal body. Exhaust pipe joint device.

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