JPH07332558A - Connecting part structure for pipe body - Google Patents

Abstract

PURPOSE:To surely hold water-tightness or air-tightness without using a gasket by simplifying a constitution. CONSTITUTION:A metal-made ring-shaped core 2, formed with a through hole 2a of diameter almost equal to an internal diameter (d) of an inner side pipe body 1 in the center part further to form a peripheral surface 2b into a circular arc shape, is provided in a spread diametric part 1a in an end part of the inner side pipe body 1 formed to curve in a circular arc shape so as to copy along the circular arc-shaped peripheral surface 2b of the core 2, and a fitting part 3a, formed with a diameter spread into a circular arc shape so as to copy along a circular arc-shaped peripheral surface 6 of the spread diametric part 1a in an end part of an outer side pipe body 3, is slidably externally fitted to the spread diametric part la. The inner side pipe body 1 is formed of material softer than the core 2 and the outer side pipe body 3, and the fitting part 3a is pressed toward the spread diametric part 1a by a fastening tool 4, to seal between the fitting part 3a and the spread diametric part 1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when connecting ends of pipes such as fire extinguishing pipes, sanitary pipes, and underground pipes, can slide relative to each other to seal the ends of the pipes. The present invention relates to a connecting portion structure of a tubular body that can be connected to a pipe.

[0002]

2. Description of the Related Art A spherical joint structure is an example of this type of connecting structure for pipes. This is because the casing is integrally formed at the end of the outer tube, the spherical portion integrally formed at the end of the inner tube is inserted into the casing through a gasket, and the spherical portion is formed at the open end of the casing. A stopper plate for preventing it from coming out of the inside is bolted, and both pipes are configured to be swingable around a spherical portion.

According to the above structure, since the gasket is used, there is an advantage that the watertightness or the airtightness can be surely maintained, but the number of parts is large, the manufacturing cost is high, and the gasket is deteriorated due to aging. Since it has the drawback of being easy to perform, it is necessary to perform frequent maintenance inspections.

To solve the above-mentioned drawbacks, there is a technique disclosed in Japanese Patent Publication No. 59-296. this is,
After inserting the outer tubular body into the first mold, a high-pressure liquid is introduced into the first metallic mold to bulge the end portion of the outer tubular body along the mold to form a spherical expanded diameter portion. And then inserting the outer tubular body into the second mold and inserting the end portion of the inner tubular body into the expanded diameter portion of the outer tubular body, and then applying high pressure into the second mold. A liquid is introduced to form a spherical inner fitting portion by bulging the end portion of the inner pipe body along the spherical inner peripheral surface of the expanded diameter portion, wherein both pipe bodies have a expanded diameter portion and It is configured to be swingable around the inner fitting portion.

[0005]

SUMMARY OF THE INVENTION In the above conventional configuration,
Although no gasket is used and the configuration is simple, in order to form the expanded diameter portion and the inner fitting portion, the first and second molds having a watertight structure and the high pressure liquid introduction device are required. The equipment cost, and consequently the production cost, are high, and moreover, since the water-tightness or airtightness is maintained by the surface contact between the expanded diameter portion and the inner fitting portion, when the fluid pressure in both pipes becomes high, There is a drawback that fluid leakage may occur between the expanded diameter portion and the inner fitting portion.

In view of the above-mentioned conventional drawbacks, the present invention provides a connecting portion structure of a pipe body having a simple structure and capable of reliably maintaining watertightness or airtightness without using a gasket. It is an object.

[0007]

In order to achieve the above object, the invention according to claim 1 is such that a through hole having substantially the same diameter as the inner diameter of the inner tubular body is formed in the central portion and the outer peripheral surface is formed in an arc shape. The metal ring-shaped core body is provided in the expanded portion of the end portion of the inner pipe body that is curvedly formed in an arc shape along the arc-shaped outer peripheral surface of the core body, and is provided at the end portion of the outer pipe body. A fitting portion that is formed in an arcuate shape along the arcuate outer peripheral surface of the expanded diameter portion is slidably externally fitted to the expanded diameter portion, and the inner tubular body is formed from the core body and the outer tubular body. Is also made of a soft material, and the fitting portion is pressed toward the enlarged diameter portion by a fastener so that the fitting portion and the enlarged diameter portion are sealed.

According to a second aspect of the present invention, there is provided a metal ring-shaped core body having a through hole having a diameter substantially the same as the inner diameter of the inner tubular body formed in the center portion and an outer peripheral surface formed in an arc shape, wherein the core body is Is provided in the expanded portion of the end portion of the inner pipe body curved along the arc-shaped outer peripheral surface of the arc-shaped outer peripheral surface of the outer pipe body so as to follow the arc-shaped outer peripheral surface of the expanded portion. A fitting portion formed to have an arcuate diameter is slidably fitted to the diameter expanding portion, and one or both of the contact surfaces of the fitting portion and the diameter expanding portion are
A sealing layer made of a softer material than both pipes is formed,
It is characterized in that the fitting portion is pressed toward the enlarged diameter portion by a fastener so that the fitting portion and the enlarged diameter portion are sealed.

According to a third aspect of the present invention, a through hole having a diameter substantially the same as the inner diameter of the inner tubular body is formed in the central portion, and a plurality of tapered surfaces having different inclination angles are continuously formed on the outer peripheral surface. The metal ring-shaped core body whose outer peripheral surface is formed in an arc shape as a whole is provided in the enlarged diameter portion of the end portion of the inner tube body formed along the outer peripheral surface of the core body, and the outer tube A fitting portion, which is formed in a circular arc shape along the outer peripheral surface of the expanded diameter portion at the end of the body, is slidably fitted on the expanded diameter portion, and the fitting portion is fixed by a fastener. It is characterized in that the fitting portion and the expanded diameter portion are sealed by pressing toward the expanded diameter portion.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the fastener is a cap nut that engages with one of the fitting portion and the enlarged diameter portion, The male screw member is engaged with the other side, and the cap nut and the male screw member are screw-fitted and fastened to each other to press the fitting portion toward the enlarged diameter portion, and the fitting portion and It is characterized in that it is sealed between the expanded diameter portion.

According to a fifth aspect of the present invention, there is provided the metal ring-shaped core body having a through hole having a diameter substantially the same as the inner diameter of the inner tube body formed in the central portion and an outer peripheral surface formed in an arc shape, wherein Is provided in the expanded portion of the end portion of the inner pipe body curved along the arc-shaped outer peripheral surface of the arc-shaped outer peripheral surface of the outer pipe body so as to follow the arc-shaped outer peripheral surface of the expanded portion. A fitting portion having an arcuately expanded diameter is slidably fitted on the expanded diameter portion, the inner tube body is made of a member having lower rigidity than the core body and the outer tube body, and It is characterized in that the fitting portion is pressed toward the expanded diameter portion to seal the space between the fitted portion and the expanded diameter portion.

According to a sixth aspect of the present invention, there is provided a metal ring-shaped core body having a through hole having a diameter substantially the same as the inner diameter of the inner tube body formed in the center and an outer peripheral surface formed in an arc shape. Is provided in the expanded portion of the end portion of the inner pipe body curved along the arc-shaped outer peripheral surface of the arc-shaped outer peripheral surface of the outer pipe body so as to follow the arc-shaped outer peripheral surface of the expanded portion. A fitting portion formed by expanding the diameter in an arc shape is slidably fitted on the expanding portion, and the fastener is pressed toward the expanding portion to expand the diameter of the fitting portion. It is characterized in that it is hermetically sealed between the parts.

[0013]

In the invention described in claim 1, when the joint is formed, the ring-shaped core body is inserted into the end portion in which the inner pipe body is formed to have the expanded diameter, and then the end portion of the inner pipe body is inserted into the core body. The outer diameter of the outer tubular body is expanded along the arcuate outer peripheral surface to form a diameter-enlarged portion by forming a diameter-enlarged portion, and a fitting portion is formed along the diameter-enlarged portion. After fitting the fitting portion to the expanded diameter portion, it is sufficient to press the fitting portion against the expanded diameter portion with a fastener.

In this case, the expanded core can be formed at the end of the inner tube by using the ring-shaped core instead of the mold, and the structure is simple and can be easily manufactured by simple equipment. As a result, the manufacturing cost is low and the joint can be easily assembled on site. Further, since the expanded diameter portion has a rigid structure due to the core body, it is also excellent in impact resistance. Furthermore, since the inner tubular body is formed of a softer material than the core body and the outer tubular body, it is possible to maintain good adhesion between the expanded diameter portion and the fitting portion, and moreover, the core body and the fastener. Since the fitting part and the expanded diameter part are sandwiched, it is possible to ensure watertightness or airtightness without using a gasket, and to prevent fluid leakage even when the fluid pressure in both pipes becomes high. There is no fear.

According to the second aspect of the present invention, it is possible to obtain the same effect as that of the first aspect of the present invention, and further, either one or both of the contact surfaces of the expanded diameter portion and the fitting portion. In addition, since the seal layer made of a material softer than both pipes is formed, the watertightness or the airtightness can be ensured more reliably.

According to the third aspect of the invention, the annular ridgeline formed at the boundary of the plurality of tapered surfaces formed on the outer peripheral surface of the expanded diameter portion is locally pressed against the inner peripheral surface of the fitting portion. Thereby, the contact surface pressure can be increased and the watertightness or airtightness can be highly maintained.

According to the fourth aspect of the present invention, by simply screwing and fastening the cap nut and the male screw member to each other, the fitting portion is firmly pressed against the expanded diameter portion to ensure watertightness or airtightness. In particular, the pressing surface of the cap nut or the male screw member that presses the outer peripheral surface of the fitting portion does not ensure watertightness or airtightness with this pressing surface, so precision machining is not required. Therefore, the manufacturing cost required for the fastener can be significantly reduced.

According to the invention described in claim 5, it is possible to obtain the same effect as that of the invention described in claim 1, and moreover, the inner tubular body is made of a member having a lower rigidity than the core body and the outer tubular body. Therefore, by pressing the fitting portion toward the expanded diameter portion with the fastener, the expanded diameter portion is deformed and adheres to the fitting portion,
Watertightness or airtightness between the two can be reliably ensured.

According to the invention of claim 6, it is possible to obtain the same effect as that of the invention of claim 1, and moreover, by pressing the fitting portion toward the expanded diameter portion with the fastener, The fitting portion and the expanded diameter portion are deformed and come into close contact with each other, and the watertightness between them can be reliably ensured.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a structure of a connecting portion of a pipe body according to a first embodiment of the present invention, in which an end portion of the inner pipe body 1 is fitted with a ring-shaped core body 2 at an enlarged diameter portion. 1a is formed, and the fitting portion 3 is fitted to the enlarged diameter portion 1a at the end portion of the outer tubular body 3.
a is formed, and a fastener 4 for pressing the fitting portion 3a toward the expanded diameter portion 1a is provided.

The core body 2 is made of stainless steel, steel or the like, and a through hole 2a having substantially the same diameter as the inner diameter d of the inner tube body 1 is formed in the center portion thereof, and the outer peripheral surface 2b is formed in an arc shape. In addition, an end surface 2c is formed at one end portion thereof along the direction orthogonal to the axial direction, and a tapered portion 2d is formed at the other end portion.

In this case, since the core body 2 can be mass-produced separately from the inner tube body 1, its manufacturing cost can be reduced.

The inner tubular body 1 is made of a metal material softer than the core body 2 and the outer tubular body 3 (for example, copper material), and its end is inserted into the arcuate outer peripheral surface of the core body 2. 2b is bent in an arc shape and is bent along the end face 2c of the core body 2 to form a step portion 5, whereby the enlarged diameter portion 1a is formed at the end portion of the inner tube body 1. Are formed.

In this case, since the inner tube body 1 is made of a softer metal material than the core body 2, the core body 2 can be easily included in the expanded diameter portion 1a.

The outer tubular body 3 is made of stainless steel or steel, and the end portion of the outer tubular body 3 is formed in an arc shape so as to follow the arc-shaped outer peripheral surface 6 of the expanded diameter portion 1a. A fitting portion 3a that is slidably fitted is formed.

In this case, since the inner tube body 1 is made of a softer material than the outer tube body 3, the close contact between the expanded diameter portion 1a and the fitting portion 3a can be maintained well.

The fastener 4 comprises a cap nut 4a and a ring-shaped male screw member 4b. The cap nut 4a is fitted onto the outer tubular body 3 and has an arcuate pressing surface 7a of the inner flange portion 7 at one end thereof. Engages with the arcuate outer peripheral surface 8 of the fitting portion 3a, the male screw member 4b is fitted onto the inner tubular body 1, and the inner peripheral edge portion thereof engages with the step portion 5 of the expanded diameter portion 1a. . Note that FIG.
Inside, 11 is a tool insertion hole for rotating the male screw member 4b.

In the above structure, the male screw portion 10 of the male screw member 4b is screwed and fastened to the female screw portion 9 of the cap nut 4a, thereby pressing the fitting portion 3a toward the expanded diameter portion 1a and fitting the fitting portion 3a. And the expanded diameter portion 1a can be sealed. In this case, since the expanded diameter portion 1a and the fitting portion 3a are clamped and clamped by the core body 2 and the fastener 4, without using a gasket, The watertightness or airtightness can be surely ensured, and there is no fear of fluid leakage even when the fluid pressure in both pipes 1 and 3 becomes high. Also, the cap nut 4a
Since the pressing surface 7a of No. does not ensure watertightness or airtightness by this pressing surface 7a, it is not necessary to perform precision processing, and it is possible to significantly reduce the cost required for manufacturing the fastener 4. You can

The procedure for forming a joint based on the above construction will be described. After the ring-shaped core body 2 is inserted into the end portion of the inner tube body 1 that is formed in a radially expanded shape (expanded tube), the inner tube is then inserted. The end portion of the body 1 is curved in an arc shape along the arc-shaped outer peripheral surface 2b of the core body 2 to form the enlarged diameter portion 1a, and the end portion of the outer tubular body 3 is formed to have a large diameter. Using a die, the fitting portion 3a is formed by expanding the diameter in an arc shape along the arc-shaped outer peripheral surface of the diameter expanding portion 1a, and fitting the fitting portion 3a onto the expanded diameter portion 1a. Next, the cap nut 4a of the fastener 4 is attached to the outer tubular body 3
It is sufficient that the male screw member 4b is externally fitted to the inner tubular body 1, and the female screw portion 9 of the cap nut 4a is screwed to the male screw portion 10 of the male screw member 4b.

In this case, the ring-shaped core body 2 can be used in place of the mold to form the expanded diameter portion 1a at the end portion of the inner tube body 1. Therefore, the ring-shaped core body 2 can be easily manufactured by a commonly used facility. It is possible and the production cost is cheap. Further, since the expanded diameter portion has a rigid structure due to the core body 2, it is also excellent in impact resistance. Furthermore, the through hole 2a of the core body 2 is
Since it is formed to have a diameter substantially the same as the inner diameter d of
It is possible to prevent turbulent flow of the fluid flowing inside.

In the above embodiment, the inner tube body 1 is made of a softer material than the core body 2 and the outer tube body 3, so that the close contact between the expanded diameter portion 1a and the fitting portion 3a can be maintained well. However, instead of this, when the inner tube body 1 is made of the same steel material or stainless steel material as the core body 2 and the outer tube body 3, as shown in FIG. A softer material (for example, a copper material or a soft synthetic material) than the two tubular bodies 1 and 3 is provided on either or both of the contact surfaces of the lapping portion 1a and the fitting portion 3a (the expanded diameter portion 1a side in this embodiment). If a sealing layer 12 coated or lined with a resin material or the like is formed, or if the inner tube body 1 is made of a softer material than the core body 2 and the outer tube body 3, the expanded diameter portion 1a
A softer material (for example, a soft synthetic resin material or the like) than the tubular bodies 1 is coated on either or both of the contact surfaces of the fitting portion 3a and the fitting portion 3a (on the expanded diameter portion 1a side in this embodiment). Alternatively, the lined seal layer 12 may be formed (second embodiment).

According to this structure, the watertightness or airtightness can be ensured more reliably, and the two pipes 1,
3 and the core 2 can be made of the same material,
The material cost can be reduced.

In both of the above embodiments, the expanded diameter portion 1a and the fitting portion 3 are
5A, the outer circumference 2b of the core 2 is continuously formed with a plurality of tapered surfaces 13 having different inclination angles, as shown in FIG. The surface 2b is formed in an arc shape as a whole, so that a plurality of similar tapered surfaces 14 having slightly different inclination angles are also formed on the outer peripheral surface 6 of the expanded diameter portion 1a, as shown in FIG.
As shown in (3), the annular ridge line 15 formed at the boundary of the tapered surface 14 may be locally pressed against the inner peripheral surface of the fitting portion 3a (third embodiment).

According to this structure, the outer peripheral surface 6 of the expanded diameter portion 1a is
The annular ridge line 15 formed at the boundary of the plurality of tapered surfaces 14 formed on the inner surface of the fitting portion 3a is locally pressed against the inner peripheral surface of the fitting portion 3a, thereby increasing the contact surface pressure and improving the watertightness or airtightness Can be maintained at. In addition, as in the first embodiment, the inner tube body 1 is formed of a metal material softer than the core body 2 and the outer tube body 3, or although not shown, as in the second embodiment, When the sealing layer 12 made of a material softer than the two pipes 1 and 3 is formed on either or both of the contact surfaces of the expanded diameter portion 1a and the fitting portion 3a, the watertightness or airtightness The sex can be maintained at a higher level.

FIG. 6 shows a fourth embodiment of the present invention in which the inner tube 1 and the outer tube 3 are made of the same material such as stainless steel or steel, but the inner tube 1 By making the wall thickness t1 of the outer tube body 3 thinner than the wall thickness t2 of the outer tube body 3 (or the wall thickness t2 of the outer tube body 3 thicker than the wall thickness t1 of the inner tube body 1). The core body 2 and the outer tube body 3 are made of a member having lower rigidity. Also,
The fastener 4 is externally fitted to the outer tubular body 3, and the arcuate inner peripheral surface 20 a of the through hole 20 penetratingly provided in the central portion of the fastener 4 has the fitting portion 3.
The outer engagement member 21 that engages with the arcuate outer peripheral surface 8 of a and the inner peripheral edge portion of the through hole 22 that is externally fitted to the inner tube body 1 and penetrates through the central portion of the outer engagement member 21 is the step portion of the expanded diameter portion 1a. 5, an inner engagement member 23 that engages with each other, and a plurality of bolts and nuts 24 that fasten the inner and outer engagement members 21, 23 to each other. Since the configuration other than the above is almost the same as that of the first embodiment, the same reference numerals are given to the same portions and the description thereof will be omitted.

According to the above construction, since the inner tube body 1 is made of a member having a lower rigidity than the core body 2 and the outer tube body 3, the fastener 4 directs the fitting portion 3a toward the expanded diameter portion 1a. By pressing it, the expanded diameter portion 1a is deformed and comes into close contact with the fitting portion 3a, and the watertightness or airtightness between the both can be reliably ensured.

FIG. 7 shows a fifth embodiment of the present invention, in which the inner tube 1 and the outer tube 3 are made of the same material such as stainless steel or steel, and the thickness t thereof is t.
1 and t2 are set to have substantially the same thin wall shape. Since the configuration other than the above is almost the same as that of the fourth embodiment, the same reference numerals are given to the same portions and the description thereof will be omitted.

According to the above construction, the fastener 4 is used to fit the fitting portion 3a.
By pressing the diametrically expanded portion 1a toward the expanded diameter portion 1a, the fitting portion 3a and the expanded diameter portion 1a are deformed and brought into close contact with each other, and the watertightness between the two can be reliably ensured. Since it is simple and the manufacturing cost is low, it is most suitable as a joint structure for communication cable protection pipes for underground underground where a high degree of sealing performance is required.

[0039]

According to the invention described in claim 1, the ring-shaped core body can be used in place of the mold to form the enlarged diameter portion at the end portion of the inner tube body, and the structure is simple, It can be easily manufactured with simple equipment, the manufacturing cost is low, and it can be easily assembled at the piping site. Further, since the expanded diameter portion has a rigid structure due to the core body, it is also excellent in impact resistance. Furthermore, since the inner tubular body is formed of a softer material than the core body and the outer tubular body, it is possible to maintain good adhesion between the expanded diameter portion and the fitting portion, and moreover, the core body and the fastener. Since the fitting part and the expanded diameter part are clamped and clamped, water tightness or airtightness can be reliably ensured without the use of gaskets, and fluid leakage even when the fluid pressure in both pipes becomes high. There is no fear of

According to the invention described in claim 2, it is possible to obtain the same effect as that of the invention described in claim 1, and further, either one or both of the contact surfaces of the expanded diameter portion and the fitting portion. In addition, since the seal layer made of a material softer than both pipes is formed, the watertightness or the airtightness can be ensured more reliably.

According to the third aspect of the invention, the annular ridge line formed at the boundary of the plurality of tapered surfaces formed on the outer peripheral surface of the expanded diameter portion is locally pressed against the inner peripheral surface of the fitting portion. Thereby, the contact surface pressure can be increased and the watertightness or airtightness can be highly maintained.

According to the fourth aspect of the present invention, by simply screwing and fastening the cap nut and the male screw member to each other, the fitting portion is firmly pressed against the enlarged diameter portion to ensure watertightness or airtightness. In particular, the pressing surface of the cap nut or the male screw member that presses the outer peripheral surface of the fitting portion does not ensure watertightness or airtightness with this pressing surface, so precision machining is not required. Therefore, the manufacturing cost required for the fastener can be significantly reduced.

According to the fifth aspect of the invention, since the inner tubular body is made of a member having lower rigidity than the core body and the outer tubular body, the fitting portion is pressed toward the expanded diameter portion by the fastener. By doing so, the expanded diameter portion is deformed and comes into close contact with the fitting portion, and the watertightness or airtightness between them can be reliably ensured.

According to the sixth aspect of the present invention, the fitting portion and the enlarged diameter portion are deformed and brought into close contact with each other by pressing the fitting portion toward the enlarged diameter portion with the fastener, and between them. The watertightness of can be reliably ensured.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a structure of a connecting portion of a pipe body according to a first embodiment of the present invention.

FIG. 2 is a view on arrow AA of FIG.

FIG. 3 is a view taken along the line BB of FIG.

FIG. 4 is a vertical cross-sectional view showing a structure of a connecting portion of a pipe body according to a second embodiment of the present invention.

FIG. 5A is a vertical cross-sectional view of a main part of a pipe connecting portion structure according to a third embodiment of the present invention, and FIG. 5B is an enlarged vertical cross-sectional view of the main part.

FIG. 6 is a vertical cross-sectional view showing a structure of a connecting portion of a pipe body according to a fourth embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view showing a structure of a connecting portion of a pipe body according to a fifth embodiment of the present invention.

[Explanation of symbols]

 1 Inner Tube 1a Expanded Part 2 Core 2a Through Hole 2b Outer Surface of Core 3 Outer Tube 3a Fitting 4 Fastener 4a Cap Nut 4b Male Thread Member 12 Seal Layer 13 Tapered Surface 14 Tapered Surface 15 Ring Ridge

Claims (6)

[Claims] 1. A metal ring-shaped core body having a through hole having a diameter substantially the same as the inner diameter of an inner tube body formed in a central portion and having an outer peripheral surface formed in an arc shape. It is provided in the expanded diameter part of the end of the inner pipe body that is curved in a circular arc shape so that it is formed in an arc shape along the arcuate outer peripheral surface of the expanded diameter part at the end of the outer pipe body. The fitted portion is slidably fitted on the expanded diameter portion, the inner tube body is formed of a softer material than the core body and the outer tube body, and the fitting portion is expanded by the fastener. A connecting portion structure of a pipe body, characterized in that the fitting portion and the expanded diameter portion are sealed by being pressed toward the portion. 2. A metal ring-shaped core body having a through hole having a diameter substantially the same as the inner diameter of the inner tubular body formed in the center and an outer peripheral surface formed in an arc shape, wherein the arc-shaped outer peripheral surface of the core body is formed. It is provided in the expanded diameter part of the end of the inner pipe body that is curved in a circular arc shape so that it is formed in an arc shape along the arcuate outer peripheral surface of the expanded diameter part at the end of the outer pipe body. The fitted fitting portion is slidably fitted onto the expanded diameter portion, and one or both of the contact surfaces of the fitting portion and the expanded diameter portion are made of a softer material than both pipes. And a sealing layer formed on the fitting portion, the fitting portion is pressed toward the enlarged diameter portion by a fastener to seal between the fitting portion and the enlarged diameter portion. Part structure. 3. A through hole having substantially the same diameter as the inner diameter of the inner tubular body is formed in the central portion, and a plurality of tapered surfaces having slightly different inclination angles are continuously formed on the outer peripheral surface to form the entire outer peripheral surface. A metal ring-shaped core body formed in an arc shape as is provided in the enlarged diameter portion of the end portion of the inner tube body formed along the outer peripheral surface of the core body, the above-mentioned at the end portion of the outer tube body. A fitting portion, which is formed in a circular arc shape along the outer peripheral surface of the expanded diameter portion, is slidably fitted over the expanded diameter portion, and the fitting portion is directed toward the expanded diameter portion with a fastener. A structure for connecting a pipe body, characterized in that a space between the fitting portion and the expanded diameter portion is sealed by pressing. 4. The fastener comprises a cap nut that engages with one of the fitting portion and the expanded diameter portion and a male screw member that engages with the other, and the cap nut and the male screw member are joined together. The screw fitting and fastening of each other presses the fitting portion toward the enlarged diameter portion, and a seal is provided between the fitting portion and the enlarged diameter portion. 3. The structure for connecting a pipe body according to any one of 3 above. 5. A metal ring-shaped core body having a through hole having a diameter substantially the same as the inner diameter of the inner tubular body formed in the center and an outer peripheral surface formed in an arc shape. It is provided in the expanded diameter part of the end of the inner pipe body that is curved in a circular arc shape so that it is formed in an arc shape along the arcuate outer peripheral surface of the expanded diameter part at the end of the outer pipe body. The fitted fitting portion is slidably fitted on the expanded diameter portion, the inner tubular body is made of a member having a lower rigidity than the core body and the outer tubular body, and the fitting portion is expanded by a fastener. A connecting portion structure for a pipe body, characterized in that the fitting portion and the expanded diameter portion are sealed by being pressed toward the diameter portion. 6. A metal ring-shaped core body having a through hole having a diameter substantially the same as the inner diameter of the inner tubular body formed in the center and an outer peripheral surface formed in an arc shape. It is provided in the expanded diameter part of the end of the inner pipe body that is curved in a circular arc shape so that it is formed in an arc shape along the arcuate outer peripheral surface of the expanded diameter part at the end of the outer pipe body. The fitted portion is slidably fitted onto the expanded diameter portion, and the fitting portion is pressed toward the expanded diameter portion by a fastener to seal between the fitted portion and the expanded diameter portion. The structure of the connecting portion of the pipe body, which is characterized in that