JP2002267062A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint capable of effectively cooling an annular seal ring by outside air and improving the durability. SOLUTION: This pipe joint A is so formed that an annular seal ring 1 having a partially conical and tapered internal circumferential seal surface 10 is provided in the internal circumferential face side of an opening end part 2a of a first exhaust pipe 52, a partially projecting-spherical surface external circumferential seal seat 30 is provided in the outer circumferential side of the opening end part 3a of a second exhaust pipe 53 facing to the annular seal ring 1, and a pressure contact means 4 is provided slidably press-contacting the internal circumferential seal surface 10 with the external circumferential seal seat 30 ranging over the both exhaust pipes 52 and 53. An outside air guiding recess part 31 to be formed with an open space S2 communicated with the external space is provided in the rear of the external circumferential seal seat 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint for connecting a fluid conduit so as to be capable of relative angular displacement and airtightly.

[0002]

Conventionally, in an exhaust system of an automobile, for absorbing the relative movement or the like of the vehicle body and the engine due to vibrations from the road surface during vibration or running of the engine, the exhaust pipe and collecting pipe of the exhaust manifold And a joint between the exhaust pipes are provided with pipe joints which are connected so as to be capable of relative angular displacement while maintaining an airtight state.

As shown in FIG. 12, for example, such a pipe joint has a tapered seal formed on an inner periphery of an integral flange 150a formed at a downstream end of a collecting pipe 150 of an exhaust manifold provided in an automobile engine. A seat 150b is formed, and the seal seat 1 is formed on the outer periphery of the connection end 151a of the exhaust pipe 151 connected to the collecting pipe 150.
An annular seal ring 100 having a convex spherical surface 100a corresponding to the tapered seal seat 150 is provided.
A configuration is widely adopted in which b and the convex spherical surface 100a are configured to be closely slidable so as to be capable of relative angular movement under the pressure of a press-contact means 140 disposed at a connection portion between the two fluid conduits.

[0004]

An annular seal ring used in a conventional pipe joint is obtained by laminating a sheet-like refractory material made of, for example, expanded graphite or mica and a thin metal wire such as stainless steel and winding and laminating the same. The mainstream is obtained by molding a truncated sphere having a cylindrical hole in the center by forcibly applying pressure from a direction perpendicular to the lamination surface in a mold of a predetermined shape, but the elasticity of the metal wire is large. For this reason, it is difficult to sufficiently secure the molding accuracy of the convex spherical surface formed on the annular seal ring. If sufficient molding accuracy is not ensured, the curvature or the center position of the convex spherical surface may be less than the initial design allowable. Because it deviates from the range, the relative angular displacement between the fluid conduits is not performed smoothly,
Vibration cannot be sufficiently absorbed, causing serious fluid leakage. In addition, as shown in FIG.
In order to secure a sealing property between the outer peripheral surface of the connecting end portion 00 and the outer peripheral surface of the connecting end portion 151a to prevent an exhaust leak, the connecting end portion 15
The annular seal ring 100 provided on the outer surface 1a is firmly press-fitted by interference fit, and the assembling work is complicated and contributes to an increase in cost.

Therefore, the present inventor disclosed in Japanese Patent Laid-Open No. 2000-291.
As disclosed in 862 JP, the annular sealing ring used in the pipe joint to form a tapered inner peripheral sealing surface that is enlarged to the opening end side, the other fluid conduit connecting portion inner peripheral sealing surface Has already been devised.

According to such a pipe joint, even if the tapered seal surface formed on the inner peripheral surface of the annular seal ring made of a thin metal wire is elastically deformed, the other fluid sliding on the seal surface is used. Since the partially convex spherical outer seal seat of the conduit is not deformed, the curvature or the center position does not deviate, the sealing performance and the smooth relative angular displacement of both fluid conduits are stably maintained, and the inner peripheral seal surface is conical. Since it is a tapered curved surface, the entire sealing surface can be formed to be thinner than the annular sealing ring of FIG. 12 having a spherical sealing surface, and the manufacturing cost of the annular sealing ring can be greatly reduced. . Further, since the outer seal seat of the other fluid conduit is located on the inner peripheral side of the annular seal ring, the annular seal ring itself is located further outside of the fluid conduit than the conventional pipe joint shown in FIG. In particular, when it is used in an exhaust system of an automobile in which a high-temperature fluid flows inside a fluid conduit, it is advantageous in cooling the annular seal ring to the outside air.

In order to further reduce the cost by forming the annular seal ring to be thinner, it is necessary to cool the annular seal ring more effectively and to improve the durability. In the structure of the disclosed embodiment, since the outer peripheral seal seat abutting the annular seal ring is formed by bulging the pipe end, fluid flows behind the outer peripheral seal seat. There was a certain limit to improving the durability of the ring.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pipe joint that can more effectively cool an annular seal ring to outside air and improve durability.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a pipe joint for connecting a first fluid conduit and a second fluid conduit so as to be capable of relative angular displacement and airtightly. Is provided with an annular seal ring having a tapered inner peripheral seal surface having an enlarged diameter at the open end side, and a partially convex spherical outer periphery facing the annular seal ring at the connection portion of the second fluid conduit. A pipe joint provided with a seal seat and provided with a press-contact means for slidably pressing an inner peripheral seal surface of an annular seal ring against the outer peripheral seal seat over the two fluid conduits, wherein an outer portion is provided behind the outer peripheral seal seat. Provided is a pipe joint, which is provided with a concave portion for introducing outside air in which an open space communicating with the space is formed.

According to such a pipe joint, the outer peripheral seal seat is cooled by the outside air introduced into the concave portion.
The annular seal ring which comes into contact therewith is cooled through the outer peripheral seal seat, and its durability is remarkably improved.

Here, it is preferable from the viewpoint of cooling that the concave portion extends at least to the vicinity of the portion where the annular seal ring is pressed against the outer peripheral seal seat.

The outer peripheral seal seat comprises an outer peripheral surface of a plate-like member which rises from the vicinity of the open end of the second fluid conduit and is bent in a partially convex spherical shape along the outer wall of the fluid conduit. It is preferable that the recess having the open space is formed between the inner peripheral surface on the back side of the plate-shaped member behind the outer peripheral seal seat and the outer wall of the second fluid conduit. According to the outer peripheral seal seat formed by bending such a plate-shaped member, the annular seal ring abutting on the outer peripheral seal seat is more effectively cooled, and the outer peripheral seal seat has a smooth surface roughness characteristic of the plate-shaped member. Since it is utilized as it is, the sealing property between the inner peripheral sealing surface of the annular seal ring and the outer peripheral sealing seat is easily stabilized, and there is no need for machining such as cutting or grinding. Shortages are avoided before they occur.

Specifically, the plate-like member constitutes a substantially disk-shaped flange member corresponding to the flange of the first fluid conduit, and the plate-like member fixed to an outer wall of the second fluid conduit. A preferred embodiment is provided with an outer peripheral seal seat which is formed by bending the plate-like member into a partially convex spherical shape on the inner peripheral end side.

It is preferable that the outer peripheral seal seat is subjected to a surface coating treatment for forming an anticorrosive lining layer or a lubricating layer.

The first fluid conduit or the second fluid conduit is
Each is a collecting pipe or an exhaust pipe of an exhaust manifold constituting an exhaust system of the internal combustion engine, and the annular seal ring is preferably made of a material having heat resistance, abrasion resistance and corrosion resistance, More specifically, in the preferred embodiment, the annular seal ring is formed by pressure-molding a thin metal wire together with a refractory material.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an overall configuration in which a pipe joint according to the present invention is employed for connecting an exhaust manifold connected to a collecting pipe of an exhaust manifold and an exhaust pipe connected thereto, and for connecting an exhaust pipe to an exhaust pipe in an automobile exhaust system. 1 to 9 show a typical embodiment of a pipe joint according to the present invention, in which reference numeral A denotes a pipe joint, and 1 denotes an annular seal ring used for the same.

As shown in FIG. 1, an exhaust system Ex of an automobile engine includes an exhaust manifold connected to a cylinder head of an engine 7 from an upstream side via a gasket 8 and a collecting pipe 51 thereof, and a plurality of exhaust pipes 52. , 53, 54,
The pipe joint A of the present invention is composed of a catalytic converter and a muffler, and is suitably used at one or more locations as a connection joint of the exhaust system Ex of these automobiles. Such a pipe joint A includes fluid pipes to be connected, that is, a collecting pipe 51 and an exhaust pipe 52, an exhaust pipe 52 and an exhaust pipe 53,
And an exhaust pipe 53 and the exhaust pipe 54 by sliding the relative angular displacement can smoothly together, airtight state between these fluid conduits (the sealing property) was maintained reliably, while preventing leakage of exhaust gases, the This is to absorb vibrations acting on the entire exhaust system Ex, such as vibrations of the engine 7 itself and vibrations caused by the running of the automobile, so as to avoid the adverse effect of the vibrations on the quietness in the room.

FIG. 2 shows, as an example, one exhaust pipe (hereinafter referred to as "first exhaust pipe") 52 through which exhaust gas from the engine 7 of the automobile flows, and communicates with the exhaust pipe. A pipe according to a representative embodiment of the present invention, which is configured as a connection joint that connects the other exhaust pipe (hereinafter, also referred to as a “second exhaust pipe”) 53 to be relatively angularly displaceable and airtight. The first exhaust pipe 52 corresponds to the first distribution conduit 2 of the present invention, and the second exhaust pipe 53 corresponds to the second exhaust pipe 53.
It corresponds to the distribution conduit 3.

That is, the pipe joint A of the present embodiment is
An annular seal ring 1 having an inner peripheral sealing surface 10 having a partially conical tapered shape whose diameter is enlarged toward the opening end of the exhaust pipe 52 is provided on the inner peripheral surface of the opening end 2 a constituting the connection portion of the exhaust pipe 52. A partially convex spherical outer peripheral seal seat 30 facing the annular seal ring 1 is provided on the outer peripheral surface side of the open end 3a constituting the connection portion of the second exhaust pipe 53, and further, A press-contact means 4 for slidably pressing the inner peripheral seal surface 10 of the annular seal ring 1 against the outer peripheral seal seat 30 over the exhaust pipes 52 and 53 is provided.

[0020] Then, behind the peripheral sealing seat 30, the recess 31 for the open space S ₂ is formed outside air introduction communicating is provided in the outer space, the present invention, such a recess 31 With this arrangement, the annular seal ring 1 is effectively cooled through the outer peripheral seal seat 30 cooled by the introduced outside air, and the durability thereof is significantly improved.

In the present embodiment, the pipe joint A used to connect the exhaust pipes 52 and 53 in the exhaust system Ex of the vehicle is exemplified. As described above, the connection between the exhaust pipe 51 and the exhaust pipe 52 can be suitably used. Further, the structure of the pipe joint of the present invention is not limited at all by the flow direction of the fluid. Therefore, in the present embodiment, it does not matter which exhaust pipe is on the upstream side, It may be upstream of the exhaust.

The annular seal ring 1 of the pipe joint A employed in the exhaust system Ex of the vehicle as in this embodiment includes:
Usually, in addition to pressure resistance, corrosion resistance, abrasion resistance, lubricity, and sealability, heat resistance and the like that can sufficiently withstand high temperatures of about 300 to 1000 ° C. are required. The annular seal ring is not limited to the one applied to the exhaust system Ex of an automobile as described above, and is suitably employed in the exhaust system of ships, motorcycles, buses, trucks, industrial machines, and other internal combustion engines and external combustion engines. In addition, it is suitably used as a connection joint in buried piping for fluid transport such as gas piping and water pipes in soft ground, which is particularly required to have vibration absorption as well as air tightness and water tightness, and exhaust piping in various power plants. You. The material and manufacturing method of the annular seal ring used for these pipe joints are appropriately selected according to the characteristics of the fluid flowing through the fluid conduit.

Hereinafter, the configuration of each part of the pipe joint A will be described in more detail.

A substantially disk-shaped cylindrical flange member 52a formed by pressing and deforming a steel plate member having the same thickness as that of the exhaust pipe 52 is provided at the pipe end 52b of the first exhaust pipe 52. Is fixed to the outside by insertion welding, and the flange member 5
2a is provided with an insertion hole 43 for inserting a set bolt 40 of the pressing means 4 to be described later and fixing it with a tightening nut 41.

The flange member 52a has a pipe end 52b.
Along the axial direction toward the second exhaust pipe 53 facing from
A tapered portion 52c that is expanded outward in a tapered shape (flare shape) is provided, and an inner peripheral side of the tapered portion 52c is formed by a tapered inner peripheral wall 21a that expands in diameter toward the opening end. A groove 21 is formed, and the annular seal ring 1 is attached to the mounting groove 21. As described above, in the pipe joint A of the present embodiment in which the annular seal ring 1 is mounted in the mounting groove 21 having the tapered inner peripheral wall 21a, the annular seal ring 1 is slid into the tapered mounting groove 21 by sliding. Compared with the conventional method in which the annular seal ring can be easily assembled, and the annular seal ring is press-fitted to the outer periphery of the pipe end with a tight fit, the dimensional tolerance of the annular seal ring 1 and the mounting groove 21 is increased, and the annular seal ring 1 is fitted. And the first
A sufficient sealing property at the fitting portion with the exhaust pipe 52 is also ensured.

The mounting groove 21 for mounting the annular seal ring 1 is not limited to the one provided with the tapered inner peripheral wall 21a. An appropriate shape, such as one that fits into the mounting groove with a tight fit, can be employed.

The flange member 52a formed by deforming the plate member under pressure is a preferred embodiment for cooling the mounted annular seal ring 1. However, a separately formed cylindrical flange member is first exhausted. The flange member 52a may be fixed to the pipe end 52b. The means for fixing the flange member 52a to the pipe end 52b may be butt welding or screw welding in addition to the insertion welding shown in this embodiment. An appropriate fixing method can be adopted according to vibration, stress, or the like.

When the first fluid conduit 2 is not the exhaust pipe 52 but the collecting pipe 51 of the exhaust manifold of the vehicle, for example, as shown in FIG.
b, an integral flange 5 also having a mounting groove 21 on the inner peripheral side.
A plurality of screw holes 40a are formed to protrude outward in the radial direction, and screw the male screw portions at the tips of the set bolts 40 of the press-contacting means 4.

As described above, a substantially tapered outer peripheral surface 13 is provided on the outer peripheral side of the annular seal ring 1 so as to correspond to the inner peripheral wall 21a of the mounting groove 21 formed in a tapered shape. On the peripheral side, the tapered outer peripheral surface 1
A tapered inner peripheral sealing surface 10 is formed substantially parallel to 3 to the opening end side to receive the opening end 3a of the second exhaust pipe 53, and FIG.
As shown in the front view of FIG. 4, the sectional view of FIG. 4, and the perspective view of FIG. 5, the inner peripheral sealing surface 10 is provided with a concave groove 11, which extends in the circumferential direction over the entire circumference. ing.

The concave groove 11 is provided in the annular seal ring 1.
The annular seal ring 1 is assembled into the mounting groove 21 of the flange member 52a as shown in FIG. When the inner peripheral seal surface 10 is pressed against the outer peripheral seal seat 30 constituted by the flange member 53a of the second exhaust pipe 53, as shown in FIG. 11, together with the bending deformation is induced by ..., annular sealing ring 1 is deformed out bay outwardly by surplus spaces S ₁ described later provided on the outer peripheral side of the annular sealing ring 1, the inner peripheral sealing surface 10 is bent and deformed in accordance with the radius of curvature of the outer peripheral seal seat 30, thereby increasing the area of close contact with the outer peripheral seal seat 30 and further improving the sealing performance.
Furthermore, the lubricant coated on the surface of the annular seal ring 1 remains in the concave groove or between the ridges even after repeated sliding, thereby reducing or avoiding the unpleasant contact noise generated in the initial stage of assembly. It also has a function and effect.

If the depth of each groove 11 is too shallow, the effect of inducing bending deformation and the effect of retaining and retaining the lubricant will not be produced, and if it is too deep, there will be problems in sealing properties and durability. Is set to 0.3 to 0.7 mm, more preferably 0.4 to 0.6 mm. In addition, each groove 1
If the width of 1 is too narrow, the effect of inducing bending deformation and the effect of remaining and retaining the lubricant do not occur, and if it is too wide, a problem occurs in the sealing property.
It is set to 1.2 mm, more preferably 0.9 to 1.1 mm. These concave grooves 11 are provided in a plurality of rows along the axial direction of the inner peripheral seal surface 10.

The outer peripheral surface 13 of the annular seal ring 1 which is in contact with the inner peripheral wall 21a of the mounting groove 21 is provided with a recess 13a extending in the circumferential direction over the entire circumference, as shown in FIG. 6 (a). As described above, when the inner peripheral wall 21a and the recess 13a are assembled in the mounting groove 21,
Surplus spaces S ₁ is formed between the, as shown in FIG. 6 (b), the bay out deformation outward of the annular seal ring 1 according to the pressure of the outer peripheral sealing seat 30 described above is allowed Become.

The annular seal ring 1 can be made of a material and a manufacturing method used for manufacturing a seal ring having a partially convex spherical surface which has been frequently used in an exhaust system of an automobile. A viscous heat-resistant sheet, heat-resistant resin, ceramic powder, or the like is inserted or filled into a mesh member knitted into a shape, and is molded in an axial direction together with an expanded graphite sheet to form the plurality of grooves 11 on the inner peripheral side. An annular seal ring having a conical tapered sealing surface having: a substantially tapered outer peripheral surface 13 having the concave portion 13a on the outer peripheral side is formed. It is preferable that the substrate be made by adding a lubricant such as molybdenum disulfide or fluorine tetranitride to the substrate.

As described above, the annular seal ring formed into a substantially tapered shape on both the inner and outer circumferences can be formed to be thin as a whole while maintaining sufficient durability, and has a partially convex spherical shape on the outer circumference side. The required amount of material is smaller and the manufacturing cost is reduced as compared with the conventional seal ring that has been molded. Preferably, the taper angles of the inner peripheral seal surface and the outer peripheral surface are approximately 20 to 40 °, respectively, and the thickness is Is 3-5m
m is formed into a truncated conical cylindrical shape.

Here, a parting line of a molding die is formed in an annular seal ring obtained by press-molding a thin metal wire, and the parting line is formed by the recess 13a described above.
If it is located at the bottom of the surface, it is possible to eliminate the influence on the sealing performance and the like.

The inner peripheral seal surface 1 of the annular seal ring 1
0 may be provided with one or more ridges instead of the above-described grooves 11,.
The invention is not limited to providing the protrusions 1 and the ridges on substantially the entire inner peripheral sealing surface, but may be provided in a limited predetermined area including a portion pressed against the outer peripheral seal seat, or may be provided without any of these. It may be configured on a suitable inner peripheral sealing surface.

As in the case of the first exhaust pipe 52, a steel plate-like member 33 having the same thickness as that of the exhaust pipe 53 is attached to the open end 3a of the second exhaust pipe 53. A substantially disk-shaped cylindrical flange member 53a formed by pressure deformation is externally fitted and fixed by insertion welding, and the flange member 53a has an insertion hole 4 through which the set bolt 40 of the press-contact means 4 is inserted.
4 and a spring seat 45 for supporting the coil spring 42 is provided.

The flange member 53a is provided with a plate-like member 33 which rises outward from the vicinity of the opening end 3a of the second exhaust pipe 53 and is bent in a partially convex spherical shape along the outer wall 32 of the exhaust pipe 53. Outer peripheral seal seat 3 which is slidably pressed against the inner peripheral seal surface 10 of the annular seal ring 1.
The outer seal seat 30 is preferably subjected to a surface coating treatment for forming an anticorrosive lining layer made of a vinyl chloride resin or an epoxy resin or a lubricating layer made of a fluorine resin as appropriate. It is an example. In the case where the partially convex spherical outer peripheral seal seat 30 is formed of the outer peripheral surface of the plate-shaped member 33 deformed under pressure as described above,
Since the smooth surface roughness characteristic of the plate member is utilized as it is, the sealing performance between the inner peripheral sealing surface 10 of the annular seal ring and the outer peripheral sealing seat 30 can be easily stabilized, and machining such as cutting and grinding can be performed. Therefore, the generation of the tool mark and the lack of the seal resulting therefrom can be avoided beforehand.

The inner peripheral surface 33 b on the back side of the plate member 33 behind the outer peripheral seal seat 30 and the outer wall 32 of the second exhaust pipe 53
And between, are formed recesses 31 for outside air intake with an open space S ₂ communicating with the outside space, behind a peripheral sealing seat the annular seal ring 1 is pressed against so that the outer space Due to the communication, the annular seal ring 1 is effectively cooled through the outer peripheral seal seat 30, and the durability thereof is remarkably improved.

The plate member 33 deformed under pressure as described above
When the outer peripheral seal seat 30 is configured by
Although the concave portion 31 is necessarily formed in substantially the entire area behind the outer peripheral seal seat 30, the structure of the outer peripheral seal seat according to the present invention is obtained by deforming the plate-shaped member 33 under pressure. However, the present invention is not limited to this.

That is, as shown in FIG. 8, the cast flange member 53e is connected to the open end 3a of the second fluid conduit 53.
Is secured to, behind the outer peripheral sealing seat 30 provided on the flange member 53e, a pipe joint also preferred embodiment the recess 31 is formed with an open space S ₂ which communicates with the external space, the recess in this case As shown in the figure, it is preferable for cooling that at least the portion 31 extends to the vicinity of the press-contact portion 30a where the annular seal ring 1 in the outer peripheral seal seat 30 presses. The concave portion 31 formed in the flange member 53e is preferably provided with an annular concave groove over the entire circumference, or provided with a plurality of concave grooves at predetermined intervals in the circumferential direction.

The outer peripheral seal seat 30 is formed by deforming the plate-like member 33 under pressure.
As shown in FIG. 9, similarly to the above-described cylindrical flange member 53 a, a substantially disk-shaped cylindrical flange provided with an outer peripheral seal seat 30 bent into a partially convex spherical shape on the inner peripheral end side of the plate member 33. A joining end 55 of the member 53b on the inner peripheral end side folded back in the tube axis direction from the open end 3a of the second fluid conduit 53;
Is inserted and fixed to the open end portion 3a of the second fluid conduit 53 by welding, or as shown in FIG. 10, a substantially disk-shaped cylindrical flange member also provided with an outer peripheral seal seat 30. A joint end 56 extending toward the open end 3a on the outer wall 32 of the second fluid conduit 53 without folding back the inner peripheral end side of the 53c, is positioned at the open end 3a and externally fitted and fixed. As shown in FIG. 11, the inner peripheral end side of the substantially disk-shaped cylindrical flange member 53d which is fitted to the second fluid conduit 53 is opened on the outer wall 32 of the second fluid conduit 53. A preferred embodiment also extends to the outer peripheral seal seat 30 which extends toward the base 3a and has its end 57 raised from the open end 3a to bend into a partially convex spherical shape.

As means for fixing these flange members to the second fluid conduit 53, similar to the case of fixing the flange member 52a to the first fluid conduit 52, butt welding and screw welding other than insertion welding are used. An appropriate fixing method can be adopted according to vibration, stress, or the like.

The press-contact means 4 includes an insertion hole 43 formed in the flange member 52a of the first exhaust pipe 52 and a second exhaust pipe 53.
A set bolt 40 communicating with an insertion hole 44 formed in the flange member 53a, a nut 41 screwed to the set bolt 40, and locking the bolt to the flange member 52a; The coil spring 42 is mounted between the flange member 53a and the bolt head 12 and biases the flange member 53a toward the first exhaust pipe 52.
The exhaust pipe 53 is connected to the first exhaust pipe 5 via the flange member 53a.
By being urged relatively to the second side, the outer peripheral seal seat 30 is pressed against the inner peripheral seal surface 10 of the annular seal ring 1 in an airtight state, and the first exhaust pipe 52 and the second exhaust pipe 53 are provided.
Are connected to each other so as to be capable of relative angular displacement. Incidentally, the press-contact means constituting the pipe joint according to the present invention is not limited to the above-mentioned structure at all, and any other structure may be employed as long as the two fluid conduits 2 and 3 can be press-bonded so as to be capable of relative angular displacement. You may.

[0045]

As described above, according to the pipe joint of the present invention,
Since the outer peripheral seal seat is cooled by the outside air introduced into the concave portion by the concave portion provided behind the outer peripheral seal seat, the annular seal ring in contact with the outer peripheral seal seat is cooled through the outer peripheral seal seat, and the durability is remarkably improved. As a result, it is possible to form the annular seal ring thinner and to pursue further cost reduction.

The outer peripheral seal seat is formed of an outer peripheral surface of a plate-like member which rises from the vicinity of the open end of the second fluid conduit and is bent into a partially convex spherical shape along the outer wall of the fluid conduit. Since the concave portion having the open space is formed between the inner peripheral surface of the plate-shaped member on the back side behind the outer peripheral seal seat and the outer wall of the second fluid conduit, the annular seal ring in contact with the concave portion is more effective. And the outer peripheral seal seat can make use of the smooth surface roughness characteristics of the plate-like member as it is, so that the sealing performance between the inner peripheral seal surface of the annular seal ring and the outer peripheral seal seat can be easily stabilized. Can,
There is no need for machining such as cutting or grinding, and the occurrence of tool marks and the resulting lack of seals can be avoided.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing an embodiment in which a pipe joint according to the present invention is employed in an exhaust system of an automobile.

FIG. 2 is an explanatory view showing a pipe joint according to a typical embodiment of the present invention.

FIG. 3 is a front view showing an annular seal ring used for the pipe joint.

FIG. 4 is a sectional view showing the annular seal ring.

FIG. 5 is a perspective view showing the annular seal ring.

FIG. 6A is an explanatory view showing a state before deformation. (B)
FIG. 4 is an explanatory view showing a state after deformation.

FIG. 7 is an explanatory view showing a modified example of a pipe joint in which a first fluid conduit is a collecting pipe of an exhaust manifold.

FIG. 8 is an explanatory view showing a modified example of a pipe joint in which a concave portion is formed behind an outer peripheral seal seat of a cast flange member.

FIG. 9 is an explanatory view showing a modified example of a pipe joint in which a plate-shaped member is deformed under pressure to form an outer peripheral seal seat.

FIG. 10 is an explanatory view showing another modified example of the pipe joint.

FIG. 11 is an explanatory view showing still another modified example of the pipe joint.

FIG. 12 is an explanatory view showing a conventional pipe joint.

[Explanation of symbols]

Reference Signs List A Pipe joint Ex Exhaust system S ₁ Surplus space S ₂ Open space 1 Annular seal ring 2 First fluid conduit 2a Open end 3 Second fluid conduit 3a Open end 4 Pressing means 6 Locking means 7 Engine 8 Gasket 10 Inner circumference Seal surface 11 Concave groove 13 Outer peripheral surface 13a Depressed portion 14 Parting line 21 Mounting groove 21a Inner peripheral wall 30 Outer peripheral seal seat 30a Pressure contact portion 31 Recess 32 Outer wall 33 Plate member 33a Outer peripheral surface 33b Inner peripheral surface 40 Set bolt 40a Screw hole 41 Nut 42 Coil spring 43 Insertion hole 44 Insertion hole 45 Spring seat 51 Collecting pipe 51a Integrated flange 51b Pipe end 52 Exhaust pipe 52a Flange member 52b Pipe end 52c Taper 53 Exhaust pipe 53a Flange member 53b Flange member 53c Flange member 53d Flange Member 53e Hula Di member 54 exhaust pipe 55 connecting end 56 joint end 57 end 100 an annular seal ring 100a convex spherical 150 collecting pipe 140 urging means 150a integral flange 150b sealing seat 151 exhaust pipe 151a connecting edge

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16L 23/16 F16L 23/02 D (72) Inventor Takeshi Harada 1-5-5 Shinsenri Higashicho, Toyonaka-shi, Osaka No. 3 Domestic Parts Industry Co., Ltd. F-term (reference) 3G004 AA01 AA02 AA03 AA04 AA05 AA06 BA00 BA02 BA04 BA07 DA01 DA11 DA21 DA22 EA00 EA03 EA06 FA04 FA07 FA09 GA06 GA07 3H016 AA02 AB06 AC02 AD02 3H104 JA03 J04 JD04 KB08 LA13 LA18 LF02 3J040 AA02 AA11 BA02 EA15 EA45 EA47 FA05 FA09 FA11 FA13 HA13 HA20

Claims (7)

[Claims] 1. A pipe joint for connecting a first fluid conduit and a second fluid conduit so as to be capable of relative angular displacement and in an airtight manner, wherein a connecting portion of the first fluid conduit has a tapered inner portion with an enlarged diameter at an open end. An annular seal ring having a peripheral seal surface is provided, and a connection portion of the second fluid conduit is provided with a partially convex spherical outer peripheral seal seat facing the annular seal ring. A pipe joint provided with a pressurizing means for slidably pressurizing the seal seat over the two fluid conduits, wherein a concave portion for introducing outside air in which an open space communicating with an external space is formed behind the outer peripheral seal seat. A pipe joint characterized by being provided. 2. The pipe joint according to claim 1, wherein said concave portion extends at least to a position near a portion of said outer peripheral seal seat where said annular seal ring is pressed. 3. The outer peripheral seal seat comprises an outer peripheral surface of a plate-like member which rises from the vicinity of an open end of the second fluid conduit and is bent in a partially convex spherical shape along an outer wall of the fluid conduit, The pipe joint according to claim 1, wherein the concave portion having the open space is formed between an inner peripheral surface of the plate-shaped member, which is behind the outer peripheral seal seat, and an outer wall of the second fluid conduit. 4. The plate-like member constitutes a substantially disk-shaped flange member corresponding to the flange of the first fluid conduit,
The pipe joint according to claim 3, wherein an outer peripheral seal seat formed by bending the plate-like member into a partially convex spherical shape is provided on an inner peripheral end side of the plate-like member fixed to an outer wall of the second fluid conduit. 5. The pipe joint according to claim 1, wherein the outer peripheral seal seat is subjected to a surface coating treatment for forming an anticorrosion lining layer or a lubricating layer. 6. The first fluid conduit or the second fluid conduit,
6. The exhaust pipe according to claim 1, wherein said annular seal ring is made of a material having heat resistance, abrasion resistance and corrosion resistance. 2. The pipe joint according to claim 1. 7. The method according to claim 1, wherein the annular seal ring is formed by pressing a thin metal wire together with a refractory material.
The pipe joint according to item.