JP6040294B2 - Pipe connection device - Google Patents

Description

  The present invention relates to a pipe connection device using an inner ring, and more specifically, high-purity liquid and ultrapure water handled in manufacturing processes in various technical fields such as semiconductor manufacturing, medical / pharmaceutical manufacturing, food processing, and chemical industry. The present invention relates to a pipe connection device suitable for the above pipes.

A pipe connecting device using an inner ring is for sealing having a cylindrical threaded portion protruding from a pipe joint main body or a fluid device in a state where a male screw is formed on the outer periphery, and an annular large-diameter portion protruding outward from the diameter. The inner ring and a union nut formed with a female screw that is screwed onto the male screw are known. For example, the one disclosed in Patent Document 1 is known.
In this Patent Document 1, a cylindrical threaded portion provided in a pipe joint body with a male screw formed on the outer periphery, an inner peripheral portion as a fluid flow passage, and an annular large diameter portion on a radially outer side. A raised inner ring for fixing a tube, and a union nut formed with a female screw that is screwed into the male screw are provided.

In the above-described pipe connection device, in order to connect the tube to the pipe joint body, first, the inner ring is press-fitted into the end portion of the tube from the opening of the tube, and the end portion of the tube is expanded and deformed by the annular large diameter portion. Next, the inner ring-formed tube whose diameter has been deformed is inserted into the cylindrical threaded portion.
Next, the female screw of the union nut is screwed into the male screw of the cylindrical screwing portion. Then, the union nut is tightened and screwed, and the union nut presses the tube with the inner ring in the axial direction by this screwing, thereby connecting the tubes.

In the above-described pipe connecting device, the union nut is tightened and tightened so that the diameter of the tube is reduced by the seal pressing portion (see the pressing edge 3C of Patent Document 1). Used as an assembled state that strongly presses in the center direction.
In the assembled state, the diameter-expanded portion of the tube and the tapered outer peripheral diameter-expanded surface (see the bulging portion 15 of Patent Document 1) are sealed, and the inner ring base end seal is sealed. The element part and the seal forming part of the pipe joint main body (see, for example, the primary seal part 5A of Patent Document 1) are pressed more strongly and sealed.

  Further, a seal portion formed by pressing a reduced diameter tube portion fitted on the reduced diameter outer peripheral surface of the narrowed inner ring and a forwardly expanded inner peripheral surface of the distal end of the cylindrical threaded portion (see Patent Document 1). A tertiary seal portion 5B) is also formed. As described above, in the conventional pipe connecting device, the a seal portion formed by the distal end portion of the inner ring and the tube, the b seal portion formed by the proximal end portion of the inner ring and the pipe joint main body, and the cylindrical screw of the pipe joint main body. It was the structure in which the seal part of each part called the c seal part by a joint part and a tube was formed.

Japanese Patent Laid-Open No. 10-054489

  In the conventional pipe connection device, the above-mentioned three seal portions exhibited good sealing performance, but continuous earnest research has found that there are the following points to be improved. I came. That is, when the contact pressure of the b-seal part b is weak or almost absent (see FIG. 10 (a)) due to size setting or error, etc., or by adding the pressure-contact forces of the a-seal part a and c-seal part c, It has been found that there are cases where the tip of the inner ring body 3A of the inner ring 3 is deformed to a reduced diameter so as to adversely affect the flow (see FIG. 10B).

For example, as shown in FIG. 10A, as the union nut 2 is tightened, the tube pressing portion 12 b presses the inner ring 3 through the tapered contact portion 4 a of the tube 4. As a result, the c-seal part c comes into strong contact, but the seal element part y and the seal forming part k are in a very light contact state or non-contact state, and the seal of the b seal part b becomes unstable. It is inconvenient.
In this case, even if leakage occurs in the b-seal part b at worst, the leakage as the pipe connecting device A can be avoided by the c-seal part c that comes into firm contact. However, the c-seal portion c, which depends on the tightening force of the union nut 2, is ideally closer to the fluid flow when the union nut 2 is loosened. It is preferable that the fluid is not soaked between the cylindrical threaded portion 1A of the pipe joint body 1 and the inner ring 3.

Further, as shown in FIG. 10B, the b-seal part b functions well, but it is not a preferable state when the c-seal part c is too strong. By tightening the union nut 2, the force in the direction of reducing the diameter of the inner ring 3 becomes excessive due to the structure of each of the a seal part a and the c seal part c, and the inner ring main body as shown in FIG. The tip of 3A is reduced in diameter and protrudes to the internal flow path R, which may impede the flow of fluid and cause a liquid pool to deteriorate the liquid replacement property.
As described above, in the conventional pipe connecting device, although the leakage does not occur immediately and there are few cases that actually cause problems, the function of the b seal portion b becomes unstable, and the tip of the inner ring main body 3A There was a possibility that the part would be excessively reduced in diameter, leaving room for improvement.

  The object of the present invention is that the further ingenuity does not cause the above-mentioned inconvenience, that is, the b-seal part functions well and the inner ring tip part does not cause excessive shrinkage deformation, and more The object is to provide an improved pipe connection device.

The invention according to claim 1 is the pipe connection device,
In order to reduce the diameter of the diameter-enlarged tube end 4C and the tapered outer diameter-expanded surface 3a that is inserted from the tip into the tube end 4C of the fluid transfer tube 4 to expand the diameter of the tube end 4C. Formed on the proximal end side of the reduced diameter outer peripheral surface 3c of the narrowed diameter and the reduced diameter outer peripheral surface 3c of the narrowed diameter, which are formed in a portion closer to the proximal end side than the outer peripheral enlarged diameter surface 3a of the tapered shape. An outer ring part 3G having a cylinder outer peripheral surface 3d having a constant outer diameter, and an inner ring 3 having an inner peripheral part 3w constituting a fluid transfer channel;
A male screw 7 formed on the outer periphery, a pre-expanded inner peripheral surface 8 formed on the inner periphery of the tip, and an inner peripheral surface 9 formed linearly with a constant diameter on the base end side of the pre-expanded inner peripheral surface 8. A pipe joint body 1 or a fluid device 1 having a cylindrical threaded portion 1A,
A female screw 13 to be screwed onto the male screw 7 and a union nut 2 having a tube pressing portion 12b on the inner periphery thereof;
Inserting the inner ring 3 in which the tube end portion 4C is externally fitted to the tapered outer peripheral surface 3a and the narrowed outer peripheral surface 3c into the cylindrical threaded portion 1A, and In the state in which the female screw 13 and the male screw 7 are screwed together and the union nut 2 is screwed in the direction of the axis Y of the cylindrical screwing portion 1A, the tube pressing portion 12b passes through the tube 4. And is configured to be able to form an assembled state that is pressed against the outer diameter expansion surface 3a of the tapered portion.
A seal element portion y is formed at the proximal end portion of the inner ring 3, and a seal forming portion k corresponding to the seal element portion y is formed in the pipe joint body 1 or the fluid device 1, respectively.
In the assembled state, the seal element part y and the seal forming part k are pressed against each other so as to be sealed, and the body pressure contact part 4d fitted on the body outer peripheral surface 3d at the tube end part 4C; The diameter-reduced tube portion 4c that is overlapped with the inner peripheral surface 9 and is fitted on the reduced diameter outer peripheral surface 3c of the narrowed portion at the tube end 4C and the tip of the inner peripheral surface 9 It is characterized by being configured to be spaced apart from the forwardly expanded inner peripheral surface 8 from the proximal end to the distal end of the forwardly expanded inner peripheral surface .

  The invention according to claim 2 is the pipe connection device according to claim 1, wherein the seal forming portion k includes a tapered outer peripheral surface 18 or a tapered inner peripheral surface 5 inclined with respect to the axis Y, and The seal element portion y is provided with an inclined inner peripheral surface 20 fitted on the tapered outer peripheral surface 18 or an inclined outer peripheral surface 11 fitted on the tapered inner peripheral surface 5.

  According to a third aspect of the present invention, in the pipe connecting device according to the first or second aspect, the seal forming portion k includes an annular groove m or / and a cylindrical portion 27 formed in parallel with the axis Y. The sealing element portion y includes a cylindrical portion 14 to be press-fitted into the annular groove m and / or an annular groove portion 28 into which the cylindrical portion 27 is press-fitted.

According to the first aspect of the present invention, in the assembled state with the union nut tightened, the reduced diameter tube portion and the cylindrical threaded portion do not come into contact with each other. Alternatively, a state is brought about in which the seal forming portion of the fluid device is reliably pressed and sealed.
That is, when the union nut is tightened, the reduced diameter tube portion that is externally fitted to the cylindrical threaded portion and the reduced diameter outer peripheral surface before the seal element portion and the seal forming portion come into contact with each other. In the assembled state, the seal element portion and the seal forming portion are not in contact with each other or lightly in contact with each other, and are externally fitted to the cylindrical threaded portion and the reduced diameter outer peripheral surface of the constriction. This is inconvenient because the reduced diameter tube portion is in strong pressure contact, and the seal due to the pressure contact between the seal element portion and the seal forming portion may not function.

Therefore, in the present invention, the reduced-diameter tube portion and the cylindrical threaded portion are configured to be separated from each other, so that a sealing function can be achieved in which the seal element portion and the seal forming portion are pressed against each other reliably and satisfactorily. It will happen.
As a result, through further improvements, the seal part by the base end part of the inner ring and the pipe joint body functions well, and excessive shrinkage deformation of the inner ring tip part does not occur, which is further improved. A pipe connection device can be provided.

  According to the first aspect of the present invention, a flared inner peripheral surface that is the inner peripheral surface of the distal end of the cylindrical threaded portion (an inner peripheral surface of the distal end that faces (ie, surrounds) the reduced diameter tube portion), and the reduced diameter tube portion. Since a gap is formed between the outer peripheral surface and the outer peripheral surface, the sealing element portion and the seal forming portion are more securely pressed against each other than when both are lightly pressed. Therefore, there is an advantage that the effect is enhanced.

  Further, as in the invention of claim 2, the seal element portion and the seal formation portion are the seal element portion on the inclined inner peripheral surface or the inclined outer peripheral surface, and the seal formation portion on the tapered outer peripheral surface or the tapered inner peripheral surface. The structure which makes a seal | sticker element part by a cylindrical part or an annular groove part, and makes a seal | sticker formation part by an annular groove or a cylindrical part like Claim 3 can be taken.

Sectional drawing of the principal part which shows the pipe | tube connection apparatus in the clamping | tightening state (Embodiment 1) Side view of partly cutout showing inner ring Side view of partly cutout showing union nut Side view of partially cut-out showing the fitting body Sectional drawing of the principal part which shows the pipe connection apparatus of 1st another structure (Embodiment 2) (A) Using a cylinder formed with the same diameter as the maximum diameter part of the inner ring, the end of the tube is expanded and deformed, and the inner periphery of the inner periphery of the end of the tube that appears there is expanded. Cross-sectional view showing the state of the radial surface, (b) is an enlarged cross-sectional view when the outer peripheral diameter-enlarged surface of the tapered inner ring is press-fitted into the end portion of the tube to expand and deform Expanded sectional view showing the main part of the first seal part Sectional drawing of the principal part which shows the pipe connection apparatus of 2nd another structure (Embodiment 3) Sectional drawing of the principal part which shows the pipe connection apparatus of 3rd another structure (Embodiment 4) The trouble state in the conventional pipe connection device is shown, (a) is a non-contact state of the second seal part, (b) is an excessively reduced diameter state of the inner ring tip part.

Hereinafter, embodiments of the pipe connection device of the present invention will be described with reference to the drawings. 1, 5, 8, in the assembled pipe connection device A, the axis Y of the pipe joint body 1, the axis Q of the union nut 2, the axis P of the inner ring 3, and the tube The four of the four axis centers X are depicted as the same line (axis Y = axis Q = axis P = axis X) arranged in a straight line.
Moreover, in this specification, in each component of the pipe joint main body 1, the union nut 2, the inner ring 3, and the tube 4, the "tip side" and the "tip" are the pipe 4 is the pipe joint in FIGS. The side (or direction) away from the main body 1 in the direction of the axis Y, and the “base end side” and “base end” are the side (or direction) where the tube 4 approaches the pipe joint main body 1 in the direction of the axis Y. Define to point. Note that “or / and” is defined to include both “or” and “and”.

Embodiment 1
As shown in FIG. 1, the pipe connection device A includes a pipe joint that connects tubes, and includes a pipe joint body 1, a union nut 2, and an inner ring 3, and an inner ring body 3 </ b> A of the inner ring 3. The tube 4 is connected in communication in a state where the tube 4 is press-fitted into the tube end 4C from the tip of the tube. The pipe joint body 1, the union nut 2, the inner ring 3, and the tube 4 are all made of a resin such as a fluororesin (eg, PTFE, PFA, ETFE, CTFE, ECTFE, etc.) having excellent heat resistance and chemical resistance.
In addition, when the pipe joint main body 1, the inner ring 3, and the tube 4 are comprised with the said fluororesin, in the union nut 2, you may form with resin, such as polyamide, a polypropylene, and polyethylene. Moreover, all of the pipe joint main body 1, the union nut 2, the inner ring 3, and the tube 4 can be formed of a resin such as polyamide, polypropylene, or polyethylene.

As shown in FIGS. 1 and 4, the pipe joint body 1 includes a cylindrical body 1 </ b> C, a cylindrical threaded portion 1 </ b> A provided on the distal end side in the axis Y direction, and a cylindrical threaded portion 1 </ b> A. The cylindrical structure has a small-diameter cylindrical portion 1a formed on the inner side of the root portion and an inner peripheral surface 6 constituting the internal flow path 6w. Although illustration is omitted, for example, the base 1C of the body portion 1C also has a cylindrical threaded portion 1A and a small-diameter cylindrical portion 1a, and is formed into a component that is symmetrical in the axial direction.
A male screw 7 is formed on the cylindrical threaded portion 1A from the outer periphery of the distal end toward the proximal end side, and an inner peripheral surface that expands toward the inner periphery of the distal end [the reduced diameter tube portion 4c in the cylindrical threaded portion 1A. 8 is formed, and a linear inner peripheral surface 9 having a constant diameter is formed on the proximal end side of the expanded inner peripheral surface 8.
A linear outer peripheral surface 10 having a constant diameter is formed on the outer diameter side of the small-diameter cylindrical portion 1a. A tip-end portion on the inner diameter side of the small-diameter cylindrical portion 1a is formed with an inclined inner peripheral surface (an example of a “tapered outer peripheral surface”) 5 that expands gradually toward the distal end of the small-diameter cylindrical portion 1a. ing.
Further, a cylindrical annular groove m is formed between the outer peripheral surface 10 of the small diameter cylindrical portion 1a and the inner peripheral surface 9 of the cylindrical screwing portion 1A.

As shown in FIGS. 1 and 3, the union nut 2 is made of a resin nut, and has a female screw 13 screwed into the male screw 7 of the cylindrical screwing portion 1 </ b> A at its inner peripheral portion, and a tip than the female screw 13. And an annular flange 12 that is located on the side and projects to the inside of the diameter.
The inner diameter portion of the flange portion 12 is set to an inner peripheral surface 12a having a diameter slightly larger than the outer diameter of the tube 4 so that the tube 4 can be inserted. The base end side of the flange portion 12 is configured as a tube pressing portion 12b that presses the outer peripheral surface of the distal end side of the tube end portion 4C into which the inner ring 3 is press-fitted in the axial direction Q of the union nut 2. In addition, on the outer periphery of the flange portion 12, six cut flat portions 2 a are formed so as to have a substantially hexagonal shape when viewed in the direction of the axial center Q and can be hooked with a spanner (wrench).

The tube pressing portion 12b is formed on an inclined inner peripheral surface that expands so that its diameter increases as it approaches the female screw 13 side (to the proximal end side) in the axial center Q direction. More specifically, the tube pressing portion 12b of the union nut 2 that sandwiches and presses the tube 4 between the tapered outer peripheral surface 3a of the inner ring 3 is tapered with respect to the axis Q. It is formed on the inclined inner peripheral surface inclined in the same direction as 3a.
Thus, when the female screw 13 is screwed into the male screw 7 of the cylindrical screwing portion 1A and the union nut 2 is screwed, the tube pressing portion 12b moves the distal end side outer peripheral surface of the tube end portion 4C along the axis Q direction. Will be pressed against. The inner peripheral surface 12a of the flange portion 12 has a constant inner diameter, but may be formed on a tapered inner peripheral surface where the inner diameter gradually increases as the distance from the female screw 13 increases.

As shown in FIGS. 1 and 2, the inner ring 3 includes an inner ring main body 3A that is press-fitted into the tube end portion 4C from the opening of the tube 4, and a tube 4 at the base end side of the inner ring main body 3A. It has a fitting cylinder portion 3B protruding from the opening to the base end side, and is configured as a cylindrical body having an axis P.
The inner ring main body 3A and each inner peripheral portion 3w of the fitting cylinder portion 3B are formed with a constant diameter and serve as a fluid flow passage.
An enlarged diameter portion 3f is formed on the distal end side of the outer peripheral portion 3G of the inner ring main body 3A, and a tapered outer peripheral enlarged surface 3a is formed on the distal end side of the enlarged diameter portion 3f. On the base end side of the diameter-enlarged portion 3f, a diameter-reduced outer peripheral surface 3c having a diameter that decreases as the diameter increases toward the base end side is formed. The largest diameter portion 3b, which is the largest diameter portion, is formed between the outer diameter-enlarged surface 3a. A barrel outer peripheral portion (cylinder outer peripheral surface) 3d having a constant outer diameter is formed on the proximal end side of the reduced diameter outer peripheral surface 3c.

  In the drawings of the present application, the maximum diameter portion 3b of the inner ring 3 is described as a structure having a certain length in the direction of the axis P, but the maximum diameter portion 3b is immediately tapered and has an outer peripheral enlarged surface. Even if it is a structure corresponding to the boundary which changes to 3a and the diameter reduction outer peripheral surface 3c of a stenosis, there is no technical problem.

The tapered outer peripheral enlarged surface 3a of the enlarged diameter portion 3f is formed into a convex curved surface that is convex outward in the radial direction, and the maximum diameter portion 3b is formed on the proximal end side of the tapered outer peripheral enlarged surface 3a. Is formed, and the tapered outer peripherally enlarged surface 3a and the maximum diameter portion 3b are press-fitted into the tube end portion 4C, whereby the tube end portion 4C is expanded and deformed.
In addition, at the distal end portion of the tapered outer peripheral diameter-enlarging surface 3a, a base-cut-shaped deformation preventing portion 16 whose diameter decreases as it proceeds toward the proximal end side of the axis P of the inner ring main body 3A is formed. Yes. By this deformation preventing portion 16, after the tapered outer diameter-enlarging surface 3 a is press-fitted into the tube end portion 4 C, the distal end portion of the diameter-enlarging portion 3 f is reduced in diameter and deformed in the radially inward direction (fluid flow path side). This can be substantially suppressed or prevented.
In addition, the deformation preventing portion 16 can prevent or suppress the distal end side of the outer peripheral diameter-enlarged surface 3a that is tapered at the momentum and speed of the fluid flow from further deforming and projecting in the radially inward direction (fluid flow path side). It is.

The fitting cylinder portion 3B includes a protruding cylindrical portion 14 that is press-fitted into the annular groove m of the pipe joint main body 1 and an annular small protruding portion 15 that is located inside the protruding cylindrical portion 14 and has an inclined outer peripheral surface 11. Is formed. On the proximal end side of the annular small protrusion 15, a tapered cut-shaped deformation prevention portion 17 whose diameter decreases as it goes toward the distal end side of the axis P of the inner ring main body 3 </ b> A is formed. By this deformation preventing portion 17, it is possible to prevent the tip end side of the annular small protruding portion 15 from deforming and projecting in the radially inward direction (fluid flow passage side).
Between the base-like inclined outer peripheral surface 11 of the annular small protrusion 15 and the inner peripheral surface 14a of the projecting cylindrical portion 14 is formed in an annular recess that expands in the base. The distal end portion of the small-diameter cylindrical portion 1a is inserted, and the inclined outer peripheral surface 11 of the annular small protrusion 15 and the inclined inner peripheral surface 5 of the small-diameter cylindrical portion 1a are brought into contact with each other by this insertion.

As shown in FIG. 1, the tube 4 has an end portion 4 </ b> C that is a base end portion thereof press-fitted and fitted into the inner ring main body 3 </ b> A. As a result, the constricted pressure contact portion 4a that is in pressure contact with the conical outer diameter expansion surface 3a, the maximum diameter expansion contact portion 4b that is in pressure contact with the maximum diameter portion 3b, and the base diameter reduction outer peripheral surface 3c. An end pressure contact portion 4c is formed at the end portion 4C. The end pressure contact portion 4c is in contact with the inner peripheral surface 9 and is pressed against the body outer peripheral portion 3d.
In a state where the tube 4 is press-fitted into the inner ring 3, the diameter of the internal flow path 4 w configured by the inner peripheral surface 4 A of the tube 4 and the diameter of the inner peripheral portion 3 w configuring the fluid flow passage of the inner ring 3. And the diameter of the inner peripheral surface 6 constituting the internal flow path 6w of the pipe joint main body 1 is the same diameter and is set to be flush with each other, but is not limited thereto.

After the inner ring body 3A is press-fitted into the tube end portion 4C of the tube 4, the tube 4 with the inner ring is inserted into the cylindrical threaded portion 1A and installed in the pipe joint body 1. Then, as shown in FIG. 1, the union nut 2 is pivoted in the tightening direction by screwing the female screw 13 of the union nut 2 into the male screw 7 of the cylindrical threaded portion 1A of the pipe joint body 1 so that the union nut 2 is pivoted to the axis Y. Screwed in the proximal direction along the axial center Q of FIG. 3, the outer peripheral surface of the distal end side of the tube end portion 4 </ b> C (the outer peripheral surface of the tapered contact portion 4 a) at the tube pressing portion 12 b of the union nut 2. Is pressed in the direction of the axis Y (axis Q in FIG. 3).
By this pressing, the protruding cylindrical portion 14 of the inner ring 3 is press-fitted into the annular groove m of the pipe joint main body 1, and the inclined outer peripheral surface 11 of the inner ring 3 abuts on the inclined inner peripheral surface 5 of the pipe joint main body 1. Press contact. Alternatively, by the pressing, the protruding cylindrical portion 14 that is lightly pressed into the annular groove m by being inserted into the cylindrical threaded portion 1A of the tube 4 with the inner ring is further forcedly pressed and press-fitted, and the inner ring 3 and the inclined outer peripheral surface 11 are brought into contact with and pressed against the inclined inner peripheral surface 5 of the pipe joint body 1.

As described above, when the tube 4 with the inner ring 3 is inserted into the cylindrical threaded portion 1A and tightened with the union nut 2, and the pipe connection device A is in the connected state (assembled state), One seal portion S1 and a second seal portion S2 are formed.
That is, the first seal portion S1 is formed by pressure contact between the tapered pressure contact portion 4a of the tube 4 and the tapered outer peripheral enlarged surface 3a of the inner ring body 3A.
Note that, by press-fitting the inner ring 3 and the tube 4, the maximum diameter expanded pressure contact portion 4b of the tube 4 and the maximum diameter portion 3b of the inner ring main body 3A are pressed, and the reduced diameter tube portion 4c of the tube 4 and the inner ring main body 3A are pressed. The diameter-reduced outer peripheral surface 3c of the base is pressed against each other, and the body pressure-contact portion 4d of the tube 4 and the body outer-periphery portion 3d of the inner ring main body 3A are pressure-contacted. The tapered contact portion 4a and the tapered outer peripheral enlarged surface 3a, the maximum expanded pressure contact portion 4b and the largest diameter portion 3b, the reduced diameter tube portion 4c, the narrowed reduced diameter outer peripheral surface 3c, and the body The pressure contact state between the pressure contact portion 4 d and the body outer peripheral portion 3 d may be strengthened by tightening the union nut 2.

The second seal portion S2 is a seal portion that includes a press-fit seal portion as on the outer peripheral side and a contact seal portion ts on the inner peripheral side.
The press-fit seal portion as is the outer peripheral surface of the fitting cylindrical portion 3B of the inner ring 3, specifically, the outer peripheral surface 14b of the protruding cylindrical portion 14 (an example of the seal element portion y) and the cylindrical threaded portion of the pipe joint body 1. Press contact with the inner peripheral surface 9 (an example of the seal forming portion k) on the base end side in 1A, and further, the inner peripheral surface of the fitting tube portion 3B, specifically, the protruding cylindrical portion 14 (an example of the seal element portion y) It is a seal part formed by press-contact with the outer peripheral surface 10 of the inner peripheral surface 14a of this, and the small diameter cylinder part 1a (an example of the seal formation part k) of the pipe joint main body 1. FIG.
The abutting seal portion ts is a state in which the diameter of the inner peripheral surface 6 of the pipe joint body 1 and the diameter of the inner peripheral portion 3w of the inner ring 3 are aligned with each other, the annular small protrusion 15 (the seal element portion y of the inner ring 3). The inclined outer peripheral surface 11 in one example) and the inclined inner peripheral surface 5 in the small-diameter cylindrical portion 1a of the pipe joint main body 1 are seal portions formed by pressure contact with each other in the axial Y direction.

By configuring the first seal portion S1 and the second seal portion S2, the fluid flowing in the tube 4, the inner ring 3, and the fitting main body 1 is bonded to the interface between the tube 4 and the inner ring 3, or the inner surface. Due to intrusion into the joint surface between the ring 3 and the pipe joint main body 1, it does not leak from between the tubular threaded portion 1A of the pipe joint main body 1 and the tube end 4C, and is completely sealed. .
As shown in FIG. 1, in the assembled state, the tip of the inner peripheral surface 9 of the cylindrical threaded portion 1A is set to a portion in the axial center Y direction of the body pressure contact portion 4d, and the tip of the inner peripheral surface 9 is By the dimension setting etc. in which the inner peripheral surface 8 is expanded, the inner peripheral surface 8 of the pipe joint body 1 and the reduced diameter tube portion 4c of the tube 4 are configured not to contact each other with a gap. . As a result, the inclined outer peripheral surface 11 and the inclined inner peripheral surface 5 are reliably brought into pressure contact with each other, so that the contact seal portion ts, that is, the second seal portion S2 functions reliably.

As the union nut 2 is tightened, if the inner peripheral surface 8 and the reduced-diameter tube portion 4c are expanded before the inclined outer peripheral surface 11 and the inclined inner peripheral surface 5 come into contact with each other, the assembly is performed. In the state, the inclined outer peripheral surface 11 and the inclined inner peripheral surface 5 do not contact or lightly contact with each other, and the expanded inner peripheral surface 8 and the reduced diameter tube portion 4c come into strong pressure contact. The seal part ts (second seal part S2) may not function, which is inconvenient.
Therefore, in the present invention, the reduced diameter tube portion 4c and the cylindrical threaded portion 1A are pressed against each other with a contact pressure lower than the contact pressure between the seal element portion y and the seal forming portion k, or in this embodiment. Since they are configured to be separated from each other as in the form, the contact seal portion ts (second seal portion S2) functions reliably and satisfactorily.

By the way, specifically, the first seal portion S1 has a pressure contact portion between the tapered pressure contact portion 4a of the tube 4 and the tapered outer peripheral enlarged surface 3a of the inner ring body 3A. The configuration is as follows.
That is, as shown in FIG. 1, the tapered outer peripheral enlarged surface 3a of the inner ring main body 3A has the entire diameter in the radial direction of the maximum diameter portion 3b of the enlarged diameter portion 3f of the inner ring main body 3A (maximum When the tube end portion 4C is expanded and deformed (in the state of only the diameter portion 3b), a naturally tapered inner peripheral expanded surface 4u [this code] appears (appears) at the inner peripheral portion of the tube end portion 4C. 4u is shown in FIG. ] And a convex curved surface, and this tapered outer diameter-enlarged surface 3a is configured to be in pressure contact with the inner circumferential portion of the tube end portion 4C.

The natural tapered outer circumferential enlarged surface 4u and the tapered outer circumferential enlarged surface 3a having a larger diameter than the tapered inner circumferential enlarged surface 4u and formed in a convex curved surface This will be described with reference to FIGS. 6 (a) and 6 (b).
The cylinder 30 with the truncated cone portion 30a shown in FIG. 6A has an outer diameter D that is the same as the maximum diameter portion 3b of the inner ring body 3A. The cylinder 30 is press-fitted from the truncated cone portion 30a into the tube end portion 4C having the axial center X with the inner diameter d which has not been expanded and deformed, and the tube end portion 4C is expanded and deformed. As a result, a naturally tapered inner circumferential enlarged surface 4u is formed between the enlarged diameter portion 4K of the tube 4 and the diameter portion 4M of the tube 4 that has not been enlarged and deformed.
In general, the shape and size of the inner circumferentially enlarged surface 4u of this natural tapered shape are different in the material of the tube 4, the thickness (thickness) t4, the diameter expansion amount [(D−d) / 2], and the like. Depending on the material, thickness t4, and diameter expansion amount of these tubes 4, their characteristics (shape and dimensions) change each time.

  On the other hand, the tapered outer peripheral enlarged surface 3a of the inner ring main body 3A has an enlarged diameter portion 3f as shown in FIG. An outline line when viewed in a cross section cut along a plane along the axis P (axis X) is formed as a curved surface that is convex toward the outside of the diameter, that is, a convex curved surface. The surface of this convex curved surface is a spherical surface that is the surface of a circular sphere, an elliptic spherical surface that is the surface of an elliptic sphere, or the like. Further, the outer diameter of the convex curved surface, that is, the diameter of the outer peripherally enlarged surface 3a of the tapered shape is larger in all directions along the axis P than the inner peripherally enlarged surface 4u of the natural tapered shape. It is formed in the diameter. In addition, t3 in FIG.6 (b) shows the thickness of the inner ring 3 in the largest diameter part 3b.

Due to the presence of the tip pressure contact portion, the inner ring 3 comes into contact with the inner peripheral portion of the tube end portion 4C over a wide range of the tapered outer peripheral enlarged surface 3a. Between the diameter surface 3 a and the inner peripheral portion of the tube 4, a wide pressure contact portion can be formed so as to cover the entire outer peripheral diameter-enlarged surface 3 a of the tapered inner ring 3.
Thereby, even if the inner ring 3 is press-fitted with a slight inclination with respect to the tube 4, the pressure contact formed between the tube end portion 4 </ b> C and the tapered outer peripheral enlarged surface 3 a of the inner ring 3. There is also an effect that it is possible to effectively prevent the fluid from permeating from the front end side of the outer peripheral diameter-enlarged surface 3a that is tapered during this time. It is done.

In the pipe connecting device A according to the present embodiment, the tapered outer peripherally enlarged surface 3a of the inner ring main body 3A is relatively convex as a spherical convex curved surface, and the natural diameter of the tube 4 is increased. The shape of the deformed portion 4H is generally a shape as shown in FIG. 6A due to the elasticity of the resin (a shape that expands into a convex curved shape when viewed from the inside of the tube). The pressure contact force between the diameter surface 3a and the tapered pressure contact portion 4a advances from the portion of the tube end portion 4C in contact with the maximum diameter portion 3b of the inner ring 3 in the direction of the axis P of the convex curved surface along the tube inner periphery. , The setting becomes larger as it approaches the intermediate value of the diameter expansion amount [(D−d) / 2]. The convex curved surface constituting the tapered outer diameter-enlarged surface 3a of the inner ring main body 3A is not limited to a spherical surface, but may be a smooth convex curved surface such as a suspended curved surface.
Therefore, even when the natural diameter-enlarged deformed portion 4H is expanded to a concave curved surface or linearly expanded, the size of the tapered outer peripheral expanded surface 3a in the direction of the axis P is increased. Instead, the tapered outer peripheral enlarged surface 3a and the tapered pressure contact portion 4a can be brought into a pressure contact state.

  Next, the pressing structure by the union nut 2 in the first seal portion S1 will be described. As described above, the tube pressing portion 12b that sandwiches and presses the tube 4 between the tapered outer peripheral surface 3a of the union nut 2 is tapered with respect to the axis Y of the cylindrical threaded portion 1A. It is formed on the inclined inner peripheral surface inclined in the same direction as the outer peripheral enlarged surface 3a. More specifically, the pressing angle θ, which is an angle with respect to the axis Y of the inclined inner peripheral surface 12b (axis Q of FIG. 3), is the axis Y of the tapered outer diameter-enlarged surface 3a (axis of FIG. 2). It is set to be larger (θ> α) than the pressure receiving angle α which is an angle with respect to P). The minimum diameter r of the inclined inner peripheral surface 12b is set to be equal to or larger (r ≧ n) than the minimum diameter n of the press-fitting fitting portion M between the tapered outer peripheral enlarged surface 3a and the tube 4. Has been. In order to obtain better sealing performance, it is desirable that the minimum diameter r of the inclined inner peripheral surface 12b and the minimum diameter n of the press-fitting fitting portion M are the same.

In FIG. 7, a press-contact portion between the tube end portion 4C and the tapered outer diameter-enlarged surface 3a, that is, a portion where the both 4C and 3a are in close contact with each other is defined as a press-fit portion M, and the press-fit portion M The point having the largest diameter is referred to as point a, the point having the smallest diameter as point b, and the smallest diameter portion (boundary point with the deformation preventing portion 16) of the tapered outer diameter expansion surface 3a as point c. . The pressure receiving angle α is an angle formed by the straight line L3 connecting the point a and the point c and the axis Y (axis P in FIG. 2), that is, an average angle of the tapered outer peripheral surface 3a. Although not shown, the pressing angle θ is naturally larger than the angle formed by the straight line connecting point a and point b and the axis Y (axis P in FIG. 2).
Further, the diameter of the inner peripheral surface 12a of the flange 12 with respect to the axis Y (axis Q of FIG. 3), that is, the minimum diameter r of the inclined inner peripheral surface 12b is the axis Y of the point b (axis Q of FIG. 3). ), That is, equal to or larger than the minimum diameter n of the press-fitting portion M (r ≧ n).

At the tip pressure contact location, by tightening (screwing) by turning the union nut 2, the inclined inner peripheral surface 12 b is a portion that is press-fitted to the outer peripheral diameter-enlarged surface 3 a that is tapered. The marginal pressure contact portion 4a is pressed in the direction of the axis Y. Since this is the structure which pushes the tube 4 with a wide surface, compared with the conventional structure pressed by the sharp corner | angular part (refer "Pushing edge 3C" of FIGS. 1, 2 of patent document 1), the tube 4 is compared. It is possible to clearly reduce the pressure (surface pressure) at the portion where the is pressed, and thus the creep phenomenon can be reduced.
In short, it does not impair the sealing performance and safety against tube disconnection, and does not require strong tightening, so the work life is greatly improved and deformation can be minimized (or minimized). Can be extended.

  According to the pipe connection device A of the first embodiment, due to the configuration of the tip pressure contact portion described above, the tapered outer peripheral enlarged surface 3a and the tube end portion 4C of the inner ring 3 are already in place before the union nut 2 is tightened. Even if the pressing force by the union nut 2 is smaller than before, sufficient sealing performance and tube retaining performance can be obtained in the first seal portion S1. The deformation can be reduced (minimized).

According to the pipe connection device A of the first embodiment, since the pressing angle θ is set to be larger than the pressure receiving angle α, the portion pressed by the inclined inner peripheral surface 12b in the tapered pressure contact portion 4a has a shaft. As the amount of compression increases in the direction of the center Y (axial center X) in the direction opposite to the pipe joint main body 1 side, a wedge action occurs, and the effect of preventing the tube 4 from coming off can be further enhanced.
That is, when a pulling force in the direction of pulling the tube 4 from the pipe joint body 1 acts on the tube 4, the tube 4 is more strongly sandwiched between the inner ring 3 and the inclined inner peripheral surface 12b that are pulled together. Accordingly, the tube 4 is also wedged in the pulling direction.
The minimum diameter r of the inclined inner peripheral surface 12b is equal to or larger than the minimum diameter n of the press-fitting fitting portion M, which is a portion where the tapered outer peripheral enlarged surface 3a and the tube 4 are in close contact with each other. Therefore, it is possible to use the union nut 2 efficiently without wasting the portion where the tapered outer diameter-enlarged surface 3a and the tube end portion 4C are not in close contact with each other, that is, without applying excessive pressing force. Tightening can be performed. In other words, it becomes possible to tighten the union nut 2 lighter than before.

In this case, if a configuration in which θ> α and r ≧ n is adopted, it is the press-fitting fitting portion that the inclined inner peripheral surface 12b pushes the tube end portion 4C most strongly by the union nut 2 being screwed. Since it is close to the minimum diameter portion of the inclined inner peripheral surface 12b at M or the minimum diameter portion thereof, the effect of preventing the tube 4 from coming off by the wedge action and the effect that the tightening force of the union nut 2 can be lightened. Has the advantage of being synergistically enhanced.
In addition, a second seal portion S2 is formed by pressure contact between a seal element portion y provided on the proximal end side of the inner ring 3 and a seal forming portion k provided on the pipe joint body 1, and these first and first Each of the two seal portions S1 and S2 provides sufficient sealing performance.

In the pipe connecting apparatus A according to the present invention, even if the inner peripheral surface 8 of the pipe joint body 1 and the reduced-diameter tube portion 4c of the tube 4 do not come into contact with each other or come into contact with each other in the assembled state, they only strike lightly. The first seal part S1 and the second seal part S2 function reliably.
That is, the first seal portion S1 prevents fluid from penetrating between the tapered outer diameter-enlarged surface 3a of the inner ring 3 and the tube 4, and the second seal portion S2 prevents the inner ring 3 from entering. Oozing between the fitting tube portion 3B and the small-diameter tube portion 1a of the pipe joint body 1 and the annular groove m is prevented. If these first and second seal portions S1 and S2 function reliably, the inner ring 3 and the cylindrical threaded portion 1A, the inner ring 3 and the tube end 4C, The fluid does not ooze between the threaded portion 1A and the tube end portion 4C.

Here, if the reduced diameter tube portion 4c and the expanded inner peripheral surface 8 are brought into pressure contact with each other in the assembled state to provide a sealing function to the pressure contact portion, the pressing force accompanying the tightening of the union nut 2 is dispersed. Thus, the pressure contact force acting on the first seal portion S1 and the second seal portion S2 may be reduced by that amount, and the seal force of the entire pipe connecting device may be reduced.
However, in the pipe connecting device A according to the present invention, the reduced diameter tube portion 4c and the forwardly expanding inner peripheral surface 8 are not pressed in the assembled state, and therefore concentrated on the first seal portion S1 and the second seal portion S2. As a result of the pressure contact force acting, it is possible to maximize the sealing force of the entire pipe connection device.
From the above, in the assembled state, is it possible to create a gap between the reduced diameter tube portion 4c and the forwardly expanded inner peripheral surface 8 rather than abutting them? The pipe connection device A is capable of reliably functioning each of the first and second seal portions S1 and S2 so that the pressure contact force is not applied, and can be more completely sealed. can do.
The tube pressing portion 12b of the union nut 2 is configured as a tapered surface as described above, and the tapered contact portion 4a at the tube end portion 4C covering the tapered outer peripheral surface 3a of the inner ring 3 is formed. You may comprise as a circular arc surface which carries out surface contact along an outer peripheral surface.

[Embodiment 2]
As shown in FIG. 5, the pipe connection device A of the second embodiment is different from the pipe connection device A of the first embodiment only in the configuration of the second seal portion S2.
That is, in the fitting cylinder portion 3B of the inner ring 3, an outer peripheral surface 3e, an inner peripheral portion 3w, and an inclined inner peripheral surface 20 that narrows toward the front end side of the inner ring 3 are formed on the rear end surface. On the other hand, in the pipe joint main body 1, the tapered outer surface 18 having a tapered outer peripheral surface 18 that becomes smaller in diameter toward the distal end side of the pipe joint main body 1 on the inner side of the root (base end side) of the cylindrical threaded portion 1 </ b> A. The small-diameter cylindrical portion 1a is formed, and the base end side of the fitting cylindrical portion 3B is fitted between the tapered outer peripheral surface 18 of the small-diameter cylindrical portion 1a and the inner peripheral surface 9 of the cylindrical threaded portion 1A. An annular groove 19 is formed.
A cut is made on the distal end side of the small-diameter cylindrical portion 1a to prevent the distal end side of the small-diameter cylindrical portion 1a from deforming and projecting in the radially inward direction (fluid flow passage side), thereby preventing the fluid from entering and staying. A shape-shaped deformation preventing portion 21 is formed.

The assembling situation in the pipe connecting device A according to the second embodiment is as follows. The union nut 2 is screwed into the tubular threaded portion 1A of the pipe fitting body 1 and screwed by tightening, and the tube pressing portion 12b of the union nut 2 is used to move the distal end side outer peripheral surface of the tube end portion 4C (constricted). The outer peripheral surface of the pressure contact portion 4a) is pressed in the direction of the axis Y.
Accordingly, the rear end portion of the fitting cylindrical portion 3B of the inner ring 3 is pushed into the annular groove 19 of the pipe joint body 1, and the tapered outer peripheral surface 18 (an example of the seal forming portion k) of the pipe joint body 1 and the inner ring. 3 inclined inner peripheral surfaces 20 (an example of the seal element portion y) are pressed against each other in the axial center Y direction to be in pressure contact with each other, thereby forming a second seal portion S2.
Then, the inclined inner peripheral surface 20 of the fitting cylinder portion 3B is in contact with the tapered outer peripheral surface 18 of the annular groove 19 so that the second seal portion S2 can function properly. The end face is preferably formed in a cut-like contact avoiding portion 25 that is spaced apart from the annular groove 19 in the axial Y direction.

  By the way, when the tensile force of the direction pulled out from the pipe joint main body 1 acts on the tube 4, in the 2nd seal | sticker part S2 in Embodiment 2, the inclination inner peripheral surface 20 and the taper outer peripheral surface 18 will move away. There is a possibility that the sealing function is lowered or released. On the other hand, in the second seal portion S2 of the first embodiment having the press-fit seal portion as on the outer peripheral side by the protruding cylindrical portion 14 and the annular groove m, the protruding cylindrical portion 14 is slightly increased as the tube 4 is pulled out and moved. Even if it is pulled out and moved, it is advantageous in that the press-fitting state between the annular groove m and the projecting cylindrical portion 14 is maintained, and therefore a sealing function is secured.

The connection between the tube 4 and the pipe joint main body 1 using the inner ring 3 in the pipe connection apparatus A according to the second embodiment is the pipe connection apparatus according to the first embodiment shown in FIGS. The configuration is the same as A. Accordingly, portions corresponding to each other in the first embodiment and the second embodiment are denoted by the reference numerals shown in FIG. 1 in FIG. 5 and the description thereof is omitted.

[Embodiment 3]
As shown in FIG. 8, the pipe connection device A of the third embodiment is only different from the pipe connection device A of the first embodiment in the configuration of the fitting cylinder portion 3B of the inner ring 3.
That is, the outer peripheral surface 3e of the fitting cylindrical portion 3B has a slightly smaller diameter than the inner peripheral surface 9 of the cylindrical threaded portion 1A, and the annular ridges 26 project in a ring shape outward from the outer peripheral surface 3e. A plurality are formed apart from each other in the axis Y direction, and the rest is the same as the pipe connection device according to the first embodiment. In this case, the plurality of annular ridges 26 and the inner peripheral surface 9 are in pressure contact with each other, and each annular ridge 26 can exhibit a sealing function.

[Embodiment 4]
As shown in FIG. 9, the pipe connection device A of the fourth embodiment is only different from the pipe connection device A of the first embodiment in the fitting structure between the proximal end portion of the inner ring 3 and the pipe joint body 1. Is.
As shown in FIG. 9, the pipe joint body 1 includes an outer circumferential groove 29 that is recessed toward the proximal end in the axial center Y direction, a cylindrical portion 27 that protrudes toward the distal end side in the axial center Y direction inside the outer circumferential groove 29, and A small-diameter cylindrical portion 1a formed inside the cylindrical portion 27 is formed.
The proximal end portion of the inner ring 3 is pressed against an outer peripheral cylindrical portion 32 fitted into the outer peripheral groove 29, an annular groove portion 28 into which the cylindrical portion 27 is press-fitted, and a tapered outer peripheral surface 18 formed in the small diameter cylindrical portion 1a. A small-diameter cylindrical portion 31 having an inclined inner peripheral surface 20 is formed.

That is, the seal element portion y that is the annular groove portion 28 and the seal forming portion k that is the cylindrical portion 27 form a press-fit seal portion as on the outer peripheral side, and the seal element portion y that is the inclined inner peripheral surface 20 and the tapered outer peripheral surface 18. The abutting seal portion ts on the inner peripheral side is formed by pressure contact with the seal forming portion k which is The outer peripheral press-fit seal portion as and the inner peripheral contact seal portion ts constitute a second seal portion S2.
In addition, each site | part which comprises the seal element part y in the pipe joint main body 1 and each site | part which comprises the seal formation part k in the inner ring 3 may be formed in the member of each reverse side. That is, the outer peripheral cylindrical portion, the annular groove portion, and the small diameter cylindrical portion may be formed on the pipe joint main body 1 side, and the outer peripheral groove, the cylindrical portion, and the small diameter cylindrical portion may be formed on the inner ring 3 side.
The configuration other than the second seal portion S2 is the same as that of the pipe connection device A of the first embodiment shown in FIG. 1, and FIG.

[Another embodiment]
The fluid transfer tube 4 to be sealed as the pipe connection device A includes a tube-like portion (cylindrical screwing portion 1A) protruding from other pipe joint main body, fluid equipment such as a pump and a valve. Shall be. In the pipe connection device A of the present invention, the fluid device 1 may be a constituent element instead of the pipe joint body 1. That is, the cylindrical screw part 1A is a pump or a valve formed integrally with the case, and these pumps and valves are collectively defined as the fluid device 1.

  1, 5, and 8, the pipe joint main body 1 has a configuration including a pre-expanded inner peripheral surface 8 that is dimensioned to form a gap with the reduced diameter tube portion 4 c in the assembled state. The structure which has the inner peripheral surface 8 of the tip expansion which contacts the diameter tube part 4c lightly may be sufficient.

1 Fitting body (fluid equipment)
DESCRIPTION OF SYMBOLS 1A Cylindrical threading part 2 Union nut 3 Inner ring 3G Outer peripheral part 3a Outer diameter enlarged surface 3c of a constriction Outer diameter outer surface of a constriction 3d Body outer peripheral surface 3w Inner peripheral part 4 Tube 4C Tube end 4c Reduced diameter Tube part 4d Body pressure contact part 5 Inclined inner peripheral surface (tapered outer peripheral surface)
7 Male thread 8 Bending inner peripheral surface (tip inner peripheral surface)
DESCRIPTION OF SYMBOLS 9 Inner peripheral surface 11 Inclined outer peripheral surface 12b Tube press part 13 Female screw 18 Tapered outer peripheral surface 20 Inclined inner peripheral surface 27 Cylindrical part 28 Annular groove part Y axial center (axial center of cylindrical screw part 1A)
m annular groove k seal forming part y seal element part

Claims (3)

An outer diameter-enlarged surface of the tapered portion that is inserted into the tube end portion of the fluid transfer tube from the distal end to expand the diameter of the tube end portion, and the tapered portion to reduce the diameter of the expanded tube end portion. A diameter-reduced outer peripheral surface of the base that is formed at a position closer to the base end side than the outer diameter-enlarged surface, and a body having a constant outer diameter formed at the base end side of the diameter-reduced outer peripheral surface of the base An outer ring having an outer circumferential surface, and an inner ring having an inner circumferential part that constitutes a fluid transfer channel;
A cylinder provided with a male screw formed on the outer periphery, a pre-expanded inner peripheral surface formed on the inner periphery of the tip, and an inner peripheral surface formed in a straight line with a constant diameter on the base end side of the inner peripheral surface of the pre-expand A pipe joint body or a fluid device having a threaded portion;
A female screw that is screwed to the male screw, and a union nut having a tube pressing portion on the inner peripheral portion,
Inserting the inner ring into which the tube end portion is externally fitted to the outer peripheral diameter-enlarging surface of the constriction and the reduced-diameter outer peripheral surface of the base constriction, and the female screw and the In a state in which the male nut is screwed and the union nut is screwed in the axial direction of the cylindrical threaded portion, the tube pressing portion is pressed against the tapered outer diameter expansion surface through the tube. The assembled state is configured so that it can be formed,
A seal element portion is formed at the base end portion of the inner ring, and a seal forming portion corresponding to the seal element portion is formed in the pipe joint main body or the fluid device, respectively.
In the assembled state, the seal element portion and the seal forming portion are pressed against each other so as to be sealed, and the body pressure contact portion and the inner peripheral surface are fitted on the tube outer peripheral surface at the tube end portion. Are overlapped so as to be in contact with each other, and the diameter-reduced tube portion that is externally fitted to the diameter-reduced outer peripheral surface of the stenosis at the tube end, and the tip-end inner peripheral surface that follows the tip of the inner peripheral surface, Is a pipe connecting device configured to be spaced apart from the proximal end to the distal end of the expanded inner peripheral surface .   The seal forming portion includes a tapered outer peripheral surface or a tapered inner peripheral surface that is inclined with respect to the axis, and the seal element portion is an inclined inner peripheral surface or the tapered inner peripheral surface that is externally fitted to the tapered outer peripheral surface. The pipe connection device according to claim 1, further comprising an inclined outer peripheral surface that fits inside.   The seal forming portion includes an annular groove or / and a cylindrical portion formed in parallel with the axis, and the cylindrical portion or / and the cylindrical portion press-fitted into the annular groove are pressed into the seal element portion. The pipe connecting device according to claim 1, further comprising an annular groove portion.

Images