JP2013076456A - Flareless tube connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability to the leak of fluid in a flareless tube connection structure using two ferrules.SOLUTION: This flareless tube connection structure (1) has a joint body (2), a coupling member (3) screwed the joint body (2), and the two ferrules (4, 5) clamped between the joint body (2) and the coupling member (3). A seal section (61) that seals the joint body (2) and a front ferrule (4) to each other is formed between the joint body (2) and front ferrule (4). A back ferrule (5) forms a seal section (63) that seals a gap between the front ferrule (4) and the back ferrule (5), between the front ferrule (4) and back ferrule. The back ferrule (5) forms a seal section (65) that seals a gap between the joint body (2) and the back ferrule (5), between the joint body (2) and the back ferrule (5) at a point downstream of the seal sections (61 and 63) in a leak direction of a fluid.

Description

  The present invention relates to a bite type pipe connection structure, and more particularly to a bite type pipe connection structure using two ferrules.

  Conventionally, in a piping system of a refrigeration system, a joint body, a coupling member that is screwed into the joint body, and the joint body and the coupling member are formed separately and between the joint body and the coupling member. A bite type pipe joint having a ferrule to be sandwiched is used.

  As the bite-in type pipe joint using such a ferrule, there are one having a single ferrule structure using one ferrule and one having a double ferrule structure using two ferrules (a front ferrule and a back ferrule). . Here, as a bite type pipe joint having a single ferrule structure, there are those described in Patent Document 1 (Japanese Utility Model Laid-Open No. 49-3111) and Patent Document 2 (Japanese Patent Laid-Open No. 2006-207795). . Moreover, as a bite type pipe joint of a double ferrule structure, there are some which are described in patent document 3 (Unexamined-Japanese-Patent No. 2005-337326) and patent document 4 (Japanese Patent Publication No. 2001-520728).

  Here, the double ferrule structure bite type pipe fitting has a higher pipe support and higher reliability as a pipe connection structure than the single ferrule structure bite type pipe joint because the front ferrule and back ferrule surely bite into the pipe. It has sex.

  However, in the conventional double ferrule structure bite type pipe joint, not only between the joint body and the front ferrule but also between the front ferrule and the back ferrule from the viewpoint of the seal between each member. The seal between the pipe and the ferrule is a double seal, which improves the leakage reliability. However, the seal (joint body and ferrule seal) other than the seal between the pipe and the ferrule has a place where fluid leaks to the outside. Therefore, there is a limit to greatly improve the reliability of fluid leakage as a whole joint.

  Further, in the bite type pipe joint having a double ferrule structure disclosed in Patent Document 3, when the coupling member is assembled to the joint body, first, the seal between the front end of the front ferrule and the joint body and the front ferrule is bite into the pipe. Done. Then, when the bite into the pipe at the tip of the front ferrule proceeds to some extent, the seal between the front ferrule and the back ferrule and the bite into the pipe of the back ferrule are then performed. When the seal between the front ferrule and the back ferrule and the biting into the pipe of the back ferrule are started, the rear end of the front ferrule and the joint body come into contact with each other, and the axial movement of the front ferrule is restricted. From the point in time, it is difficult for the front ferrule to bite into the pipe at the tip. Further, when the front ferrule is pressed by the back ferrule while the axial movement is constrained, a rotational moment is generated on the front ferrule around the position where the axial movement is constrained. This rotational moment generates a force that reduces the surface pressure between the tip of the front ferrule and the pipe. For this reason, there is a risk of insufficient biting into the piping of the front ferrule. As described above, in the bite type pipe joint having the double ferrule structure of Patent Document 3, the sealing performance between the front ferrule and the piping is lowered, and the reliability against fluid leakage may be impaired.

  Furthermore, in a bite type pipe joint having a double ferrule structure, when the assembled coupling member is removed from the coupling body due to the requirement for relocation of the refrigeration system, and then the coupling member is reassembled to the coupling body, both ferrules are already used. Is in a deformed state. For this reason, when reassembling, the front ferrule is hardly subjected to the pressing force against the joint body, and the sealing performance between the front ferrule and the piping is lowered, so the reliability against fluid leakage is greatly increased. May be damaged.

  An object of the present invention is to improve the reliability against fluid leakage in a bite type pipe connection structure using two ferrules.

  The bite type pipe connection structure according to the first aspect includes a joint body, a coupling member screwed into the joint body, and a joint body and the coupling member. A front ferrule and a back ferrule sandwiched between the two. The front ferrule forms a joint body-front ferrule seal portion that seals between the joint body and the front ferrule with the joint body. The back ferrule forms a front ferrule-back ferrule seal portion that seals between the front ferrule and the back ferrule with the front ferrule. Moreover, the back ferrule is located between the joint body and the back ferrule at a position downstream of the joint body-front ferrule seal portion and the front ferrule-back ferrule seal portion with respect to the fluid leakage direction. A joint main body-back ferrule seal portion that seals the gap is formed.

  In this bite-type pipe connection structure, the fluid leaking through the joint body-front ferrule seal portion and the fluid leaking through the front ferrule-back ferrule seal portion merge to reach the joint body-back ferrule seal portion. . Therefore, the fluid leaking through the joint body-front ferrule seal portion is sealed at the joint body-back ferrule seal portion arranged in series with respect to the fluid leakage direction, and fluid leakage to the outside is suppressed. . In addition, the fluid leaking through the seal part between the front ferrule and the back ferrule is also sealed at the joint body-back ferrule seal part arranged in series with respect to the fluid leakage direction, thereby suppressing the leakage of the fluid to the outside. Moreover, the joint body-back ferrule seal part is common to the joint body-front ferrule seal part and the front ferrule-back ferrule seal part, so that the location where fluid leaks to the outside compared to the conventional double ferrule structure Will be reduced by one place.

  Thereby, in this bite type pipe connection structure, since the seal portion is arranged in series and the number of places where the fluid leaks to the outside can be reduced, the reliability against fluid leakage can be improved.

  The bite type pipe connection structure according to the second aspect is the bite type pipe connection structure according to the first aspect. In the bite type pipe connection structure according to the first aspect, the front ferrule presses the back ferrule radially inward when the coupling member is assembled to the joint body. It has a front ferrule-back ferrule pressing surface that generates a force to generate. The joint body includes a joint body-front ferrule pressing surface that generates a force that presses the front ferrule radially inward when the coupling member is assembled to the joint body, and a back ferrule when the coupling member is assembled to the joint body. And a joint body-back ferrule pressing surface that generates a force that presses the inner surface toward the radially inner side.

  In this bite type pipe connection structure, the joint body-front ferrule pressing surface bites into the pipe of the front ferrule to form a seal part between the front ferrule and the pipe and a seal part between the joint body and the front ferrule. To do. Further, the front ferrule-back ferrule pressing surface bites into the pipe of the back ferrule to form a seal part between the back ferrule and the pipe and a seal part between the front ferrule and the back ferrule. Moreover, the joint body-back ferrule pressing surface further advances the biting of the back ferrule into the pipe, and forms the joint body-back ferrule seal portion.

  Thereby, in this bite type pipe connection structure, it is possible to reliably bite both pipes into the pipe and to form a seal part between the joint main body and the back ferrule, thereby improving the reliability against fluid leakage. Can do.

  The bite type pipe connection structure according to the third aspect is the bite type pipe connection structure according to the second aspect, wherein the joint body has a ferrule housing part for housing the front ferrule. The ferrule housing part forms a joint body-front ferrule seal part with the front ferrule. The ferrule housing part further houses a part of the back ferrule, and forms a joint body-back ferrule seal part with the back ferrule.

  In this bite type pipe connection structure, in the ferrule housing portion, it is possible to suppress fluid leakage from between the front ferrule and the joint body and fluid leakage from between the joint body and the back ferrule.

  The bite type pipe connection structure according to the fourth aspect is the bite type pipe connection structure according to the third aspect, wherein the outer diameter of the back ferrule is larger than the outer diameter of the front ferrule. The ferrule housing portion forms a joint body-back ferrule seal portion between the joint body and the front ferrule and a back ferrule at a position on the radially outer side of the seal portion between the joint body and the front ferrule and the front ferrule and the back ferrule. Yes.

  In this bite-in type pipe connection structure, by forming the outer diameter of the back ferrule larger than the outer diameter of the front ferrule, the seal portion between the joint body and the back ferrule is formed at a position on the radially outer peripheral side of the other seal portion. Can do.

  The bite type pipe connection structure according to the fifth aspect is the bite type pipe connection structure according to the third or fourth aspect, in the state in which the coupling member is assembled to the joint body in a state before the coupling member is assembled to the joint body. With respect to a certain fastening direction, the rear end of the front ferrule housed in the ferrule housing part is located on the rear side of the ferrule housing part.

  In this bite type pipe connection structure, the rear end of the front ferrule is located on the rear side of the ferrule housing portion before the coupling member is assembled to the joint body. For this reason, when the coupling member is assembled to the joint body, the rear end of the front ferrule is first housed in the ferrule housing portion, and the joint body-front ferrule seal portion is formed and the front ferrule is bite into the pipe. Is done. Then, when the biting of the front ferrule into the pipe proceeds, the formation of the front ferrule-back ferrule seal portion and the biting of the back ferrule into the pipe are then performed. Furthermore, when the assembly of the coupling member to the joint body proceeds, not only the rear end of the front ferrule but also a part of the back ferrule is accommodated in the ferrule accommodating portion. Then, the back ferrule comes into contact with the joint body-back ferrule pressing surface of the joint body, and the biting of the back ferrule into the pipe further proceeds, and the joint body-back ferrule seal portion is formed.

  Thus, in this bite type pipe connection structure, between the joint body and the pipe and the front ferrule, between the front ferrule and the pipe and the back ferrule, and between the members in the order between the joint body and the back ferrule. Sealing can be performed.

  The bite type pipe connection structure according to the sixth aspect is the bite type pipe connection structure according to any of the second to fifth aspects, wherein the joint body-front ferrule pressing surface, front ferrule-back ferrule pressing surface, and The joint body-back ferrule pressing surface forms an inclined surface whose diameter decreases toward the front side with respect to the fastening direction.

  In this bite type pipe connection structure, when the assembly of the coupling member to the joint body proceeds to the state where the joint body-back ferrule seal portion is formed, the front ferrule is further pressed toward the fastening direction through the back ferrule. It will be. For this reason, in this bite-in type pipe connection structure, the biting into the pipe of the front ferrule further proceeds even after the biting into the pipe of the back ferrule is started. Further, even when the coupling member is reassembled to the joint body using the ferrule that has been deformed by being used for assembling, the front ferrule can bite into the pipe.

  As a result, with this bite-in type pipe connection structure, it is possible to make it difficult for the front ferrule to bite into the pipe, and to ensure reliability against fluid leakage even when the coupling member is reassembled into the joint body. can do.

  The bite type pipe connection structure according to the seventh aspect is the bite type pipe connection structure according to any of the first to sixth aspects, wherein the upstream side of the seal part between the joint body and the front ferrule with respect to the fluid leakage direction. Is provided with an O-ring seal.

  In this bite type pipe connection structure, since the seal portion is further arranged in series with respect to the fluid leakage direction, the reliability against fluid leakage can be further improved.

  As described above, according to the present invention, the following effects can be obtained.

  In the bite type pipe connection structure according to the first aspect, since the seal portions are arranged in series and the number of places where the fluid leaks to the outside can be reduced, the reliability against fluid leakage can be improved.

  In the bite type pipe connection structure according to the second aspect, it is possible to reliably bite both the ferrules into the pipe and to form a seal part between the joint body and the back ferrule, thereby improving the reliability against fluid leakage. Can be made.

  In the bite type pipe connection structure according to the third aspect, in the ferrule housing portion, it is possible to suppress fluid leakage from between the front ferrule and the joint body and fluid leakage from between the joint body and the back ferrule. it can.

  In the bite type pipe connection structure according to the fourth aspect, by making the outer diameter of the back ferrule larger than the outer diameter of the front ferrule, the seal between the joint main body and the back ferrule is positioned at the radially outer peripheral side of the other seal portion. The part can be formed.

  In the bite type pipe connection structure according to the fifth aspect, between each member in the order between the joint body and the pipe and the front ferrule, between the front ferrule and the pipe and the back ferrule, and between the joint body and the back ferrule. Can be sealed.

  In the bite type pipe connection structure according to the sixth aspect, it is possible to make it difficult for the front ferrule to bite into the pipe, and even when reassembling the coupling member to the joint body, reliability against fluid leakage is ensured. Can be secured.

  In the bite type pipe connection structure according to the seventh aspect, since the seal portion is further arranged in series with respect to the fluid leakage direction, the reliability against fluid leakage can be further improved.

It is sectional drawing which shows the state at the time of the pipe connection start of the bite type pipe connection structure concerning one Embodiment of this invention. It is sectional drawing which expands and shows the A section of FIG. It is an expanded sectional view showing the state of pipe connection initial stage of the bite type pipe connection structure. It is an expanded sectional view showing the state of the pipe connection middle stage of the bite type pipe connection structure. It is an expanded sectional view which shows the state of the pipe connection latter stage of a bite type pipe connection structure. It is sectional drawing which shows the state at the time of pipe connection completion of a bite type pipe connection structure. It is a figure which shows the relationship between the rotation angle of a coupling member at the time of pipe connection of a bite type pipe connection structure, and a ferrule pressing force (at the time of new use). It is a figure (at the time of reuse) which shows the relationship between the rotation angle of a coupling member at the time of pipe connection of a bite type pipe connection structure, and a ferrule pressing force. It is sectional drawing which shows the state at the time of the pipe connection start of the bite type pipe connection structure in the modification 1. It is sectional drawing which shows the state by which the back ferrule and the coupling member in the modification 1 were temporarily assembled. It is sectional drawing which expands and shows the B section of FIG. 10 is a cross-sectional view showing a coupling member in Modification 1. FIG. It is sectional drawing which shows the back ferrule in the modification 1. FIG. It is sectional drawing which shows the state at the time of the completion of pipe connection of the bite type pipe connection structure in the modification 1. It is sectional drawing which shows the state at the time of the completion of pipe connection of the bite type pipe connection structure in the modification 2. It is sectional drawing which shows the state at the time of the pipe connection start of the bite type pipe connection structure in the modification 3. It is sectional drawing which shows the state at the time of the completion of pipe connection of the bite type pipe connection structure in the modification 3. It is sectional drawing which shows the state at the time of the completion of pipe connection of the bite type pipe connection structure in the modification 4. It is sectional drawing which shows the state at the time of the pipe connection start of the bite type pipe connection structure in the modification 5. 10 is a cross-sectional view showing a joint body in Modification 5. FIG. 10 is a cross-sectional view showing a coupling member in Modification 5. FIG. FIG. 16 is a rear view showing a coupling member in Modification 5. It is sectional drawing which shows the state at the time of the completion of pipe connection of the bite type pipe connection structure in the modification 5. It is a perspective view which shows the principal part of the exclusive jig | tool of the bite type pipe connection structure in the modification 5. It is sectional drawing which shows the state at the time of the pipe connection start of the bite type pipe connection structure in the modification 6. It is sectional drawing which shows the state (state just before a cutting | disconnection) at the time of pipe connection completion of the bite type pipe connection structure in the modification 6. It is sectional drawing which shows the state (state after a cutting | disconnection) at the time of pipe connection completion of the bite type pipe connection structure in the modification 6.

  Hereinafter, an embodiment of a bite type pipe connecting structure according to the present invention will be described based on the drawings.

<Configuration>
The bite type pipe connection structure 1 of this embodiment is applied to a pipe joint portion in a pipe joint for connecting pipes to each other in a piping system of a refrigeration apparatus such as a heat pump type air conditioner or a hot water apparatus, or a pipe is connected. It is applied to a pipe joint part in devices such as valves. Here, FIG. 1 is a cross-sectional view showing a state at the start of pipe connection of the bite type pipe connection structure 1 according to one embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a portion A of FIG. FIG. 3 is an enlarged cross-sectional view showing a state of the pipe connection initial state of the bite type pipe connection structure 1. FIG. 4 is an enlarged cross-sectional view showing a state in the middle of the pipe connection of the bite type pipe connection structure 1. FIG. 5 is an enlarged cross-sectional view showing a state of the pipe connection late stage of the bite type pipe connection structure 1. FIG. 6 is a cross-sectional view showing a state when the pipe connection of the bite type pipe connection structure 1 is completed. FIG. 7 is a diagram (when newly used) showing the relationship between the rotation angle of the coupling member 3 and the ferrule pressing force when the pipe of the bite type pipe connection structure 1 is connected. FIG. 8 is a diagram (when reused) showing the relationship between the rotation angle of the coupling member 3 and the ferrule pressing force when the pipe of the bite type pipe connection structure 1 is connected. In addition, “front” and “rear” used in the following description mean a direction based on a fastening direction that is a direction in which the coupling member is assembled to the joint body, and in FIG. Let it be “front”, and the side facing the right side of the page is “back”. “Axial direction” means a direction along the axis of each member, and “radial direction” means a direction intersecting the axial direction. 3 to 6 and the like are image diagrams showing a state in which the ferrules 4 and 5 bite into the pipe P2. The state in which the ferrules 4 and 5 actually bite into the pipe P2 is actually the same as that shown in FIGS. It may be slightly different.

  The bite type pipe connection structure 1 mainly includes a joint body 2, a coupling member 3, a front ferrule 4 and a back ferrule 5. The joint body 2 is a member attached to the pipe P1 led out from the connected side device. The coupling member 3 is a member that is externally mounted on the pipe P <b> 2 connected to the joint body 2 and is screwed into the joint body 2 to be assembled. The front ferrule 4 and the back ferrule 5 are members that are formed separately from the joint body 2 and the coupling member 3 and are sandwiched between the joint body 2 and the coupling member 3. The pipes P1 and P2 are metal members such as copper.

  The joint body 2 is a member made of metal such as brass, and has a base portion 21 formed in a substantially hexagonal nut shape so that it can be gripped by a general-purpose fastening tool. A socket portion 22 is formed on the front side of the base portion 21, and a shaft portion 23 is formed on the rear side of the base portion 21. A screw portion 23 a made of a male screw for screwing the coupling member 3 is formed on the outer peripheral portion of the shaft portion 23. An insertion port 24 for inserting the pipe P <b> 1 is formed in an axial center portion from the socket portion 22 to the base portion 21. An insertion port 25 for inserting the pipe P <b> 2 is formed in the axial center portion from the shaft portion 23 to the base portion 21. Between the insertion port 24 and the insertion port 25 in the axial direction, a communication hole having a smaller diameter than that of the insertion port 24 and the insertion port 25 is formed, and the stepped portion 26 that restricts the axial movement of the pipes P1 and P2. Is formed. The stepped portion 26 keeps the tip positions of the pipes P1 and P2 constant by bringing the tips of the pipes P1 and P2 inserted into the insertion ports 24 and 25 into contact with the stepped portion 26. A ferrule housing portion 27 that houses the front ferrule 4 is formed at the tip portion of the shaft portion 23, that is, the rear end portion of the insertion port 25. A cam surface 27 a (joint body—front ferrule pressing surface) is formed on the front portion of the ferrule housing portion 27. The cam surface 27a has an inclined surface whose front portion is continuous with the insertion port 25 and whose diameter increases toward the rear side. The cam surface 27 a generates a force that presses the front ferrule 4 toward the radially inner peripheral side when the coupling member 3 is assembled to the joint body 2. The cam surface 27a is formed so that the inclination angle α2 with respect to the axis of the front portion is larger than the inclination angle α1 with respect to the axis of the rear portion (see FIG. 2). In addition, a cylindrical surface 27 b is formed at an intermediate portion of the ferrule housing portion 27. The front surface of the cylindrical surface 27b is continuous with the cam surface 27a and forms a flat surface whose diameter does not change in the front-rear direction. Further, a taper surface 27c (joint body-back ferrule pressing surface) is formed in the rear portion of the ferrule housing portion 27. The tapered surface 27c has a front surface portion that is continuous with the cylindrical surface 27b, and forms an inclined surface whose diameter increases toward the rear side. That is, the taper surface 27c continues to the rear side of the cam surface 27a via the cylindrical surface 27b, and is disposed on the radially outer peripheral side of the cam surface 27a. The taper surface 27c generates a force that presses the back ferrule 5 toward the radially inner periphery side when the coupling member 3 is assembled to the joint body 2. Here, the inclination angle of the tapered surface 27c with respect to the axis is α3 (see FIG. 2). And the ferrule accommodating part 27 accommodates the front part of the front ferrule 4 in the state in which the rear end of the front ferrule 4 is located on the rear side of the ferrule accommodating part 27 before the coupling member 3 is assembled to the joint body 2. (See FIG. 2).

  The coupling member 3 is a metal member such as brass, and has a base 31 in which an insertion port 32 for inserting the pipe P2 is formed in the axial center portion. On the front side of the base portion 31, a fastening portion 33 that is screwed with the joint body 2 is formed. A screw portion 33 a made of an internal thread that is screwed into the screw portion 23 a of the joint body 2 is formed on the inner peripheral portion of the fastening portion 33. The outer peripheral part from the base 31 to the fastening part 33 is formed in a substantially hexagonal nut shape so that it can be gripped by a general-purpose fastening tool. A pressing surface 34 is formed on the front portion of the base 31. The pressing surface 34 forms an inclined surface whose axial center side retreats backward. When the coupling member 3 is assembled to the joint body 2, the pressing surface 34 replaces the tightening torque for tightening the coupling member 3 with the force pressing the axially front side and the radially inner side, and the back ferrule 5. Is to press.

  The front ferrule 4 is a member made of metal such as brass, and is formed separately from the back ferrule 5 in a state before the coupling member 3 is assembled to the joint body 2. A pipe through hole 41 into which the pipe P <b> 2 is inserted is formed in the axial center portion of the front ferrule 4. In the front ferrule 4, the front part constitutes the front part 42 and the rear part constitutes the rear part 43. On the outer peripheral surface of the front portion 42, a tapered surface 42a whose diameter decreases toward the front is formed. The tapered surface 42a is formed such that the inclination angle β1 with respect to the axis is smaller than the inclination angle α1 of the rear portion of the cam surface 27a (see FIG. 2). A notch 42b is formed on the inner peripheral surface of the front portion 42. The notch 42b is cut toward the outer peripheral side in the radial direction. The notch 42b has a substantially right triangle shape in cross section along the axial direction. This is for facilitating deformation of the front end portion of the front portion 42, that is, the portion in front of the notch 42b. The outer peripheral surface of the rear part 43 is formed with a surface substantially parallel to the axis. On the inner peripheral surface of the rear portion 43, a tapered surface 43a (front ferrule-back ferrule pressing surface) whose diameter decreases toward the front is formed. The tapered surface 43a generates a force that presses the back ferrule 5 toward the radially inner periphery when the coupling member 3 is assembled to the joint body 2. Here, an inclination angle with respect to the axis of the tapered surface 43a is β2 (see FIG. 2).

  The back ferrule 5 is a metal member such as brass, and is formed separately from the front ferrule 4 in a state before the coupling member 3 is assembled to the joint body 2. A pipe through hole 51 into which the pipe P <b> 2 is inserted is formed in the axial center portion of the back ferrule 5. In the back ferrule 5, the front part forms the front part 52, and the rear part forms the rear part 53. The outer diameter Db of the front part 52 of the back ferrule 5 is larger than the outer diameter Df of the rear part 43 of the front ferrule 4 (see FIG. 2). The radially inner peripheral portion of the outer peripheral surface of the front portion 52 faces the rear portion 43 of the front ferrule 4, and an inner peripheral tapered surface 52a that decreases in diameter toward the front is formed. Moreover, the radial direction outer peripheral part of the outer peripheral surface of the front part 52 is facing the taper surface 27c of the coupling main body 2, and the outer peripheral side taper surface 52b which a diameter becomes small as it goes to the front is formed. Here, the inner peripheral side tapered surface 52a is formed such that the inclination angle γ1 with respect to the axial center is smaller than the inclination angle β2 of the tapered surface 43a of the front ferrule 4 (see FIG. 2). Further, the outer peripheral taper surface 52b is formed such that the inclination angle γ2 with respect to the axial center is larger than the inclination angle α3 of the taper surface 27c of the joint body 2 (see FIG. 2). Here, the outer peripheral taper surface 52b is formed so as to be smoothly connected to the radially outer peripheral side of the inner peripheral taper surface 52a, and the inclination angle γ1 and the inclination angle γ2 are the same angle. However, the present invention is not limited to this, and the inclination angle γ1 and the inclination angle γ2 may be different.

<Method>
Next, a pipe connection method using the bite type pipe connection structure 1 of the present embodiment configured as described above will be described.

  Prior to connecting the pipe P2, the joint body 2 is attached to the pipe P1 derived from the connected device. Next, connection of the piping P2 by the bite type pipe connection structure 1 is performed by first inserting the piping P2 to be connected to the insertion port 32 of the coupling member 3 and mounting the coupling member 3 on the piping P2. Next, the pipe P2 is inserted into the pipe through holes 41 and 51 of the front ferrule 4 and the back ferrule 5, and the front ferrule 4 and the back ferrule 5 are externally attached to the pipe P2. The front end portion of the pipe P2 is inserted into the insertion port 25 of the joint body 2 so that the pipe P2 is in contact with the stepped portion 26, and the front ferrule 4 and the back ferrule 5 that are temporarily assembled with each other are placed between the axial directions. The coupling member 3 is screwed into the joint main body 2 while being sandwiched between the two.

  When the coupling member 3 is manually fastened to the joint body 2 from this state, the rear portion 53 of the back ferrule 5 is pressed forward by the pressing surface 34 of the coupling member 3. Further, the rear portion 43 of the front ferrule 4 is pressed forward by the front portion 52 of the back ferrule 5. Thereby, the taper surface 42a of the front part 42 of the front ferrule 4 contacts the rear side portion of the cam surface 27a of the joint body 2. At this time, a portion of the front portion 42 of the front ferrule 4 that is in front of the notch 42b is bent radially inward and is temporarily fixed to the front portion of the cam surface 27 (the portion of the inclination angle α2). Further, the inner peripheral side tapered surface 52 a of the front portion 52 of the back ferrule 5 contacts the tapered surface 43 a of the rear portion 43 of the front ferrule 4.

  From this state, the coupling member 3 is fastened to the joint body 2 using a general-purpose fastening tool.

  Then, first, at the initial stage of tightening (initial stage of pipe connection), the tapered surface 42a is pressed against the cam surface 27a, and the cam surface 27a formed of an inclined surface presses the front portion 42 of the front ferrule 4 toward the radially inner peripheral side. To generate power. And by this pressing force, the front part 42 of the front part 42 bites into the pipe P2 (see FIG. 3). At this time, since the inclination angle β1 of the tapered surface 42a is smaller than the inclination angle α1 of the rear portion of the cam surface 27a (see FIG. 2), the front portion 42 of the front ferrule 4 is pressed radially inward. You can strengthen the power to do. Further, the rear end of the front ferrule 4 is housed in the ferrule housing portion 27 (see FIG. 3). As a result, a seal portion 61 (a seal portion between the joint body and the front ferrule) between the cam surface 27a of the joint body 2 and the tapered surface 42a of the front ferrule 4 is formed (see FIG. 3). At the same time, a seal portion 62 (front ferrule-pipe seal portion) between the front end of the front ferrule 4 and the pipe P2 is formed (see FIG. 3).

  Next, biting into the pipe P2 at the front end of the front ferrule 4 proceeds to some extent, and is in the middle period of tightening (middle period of pipe connection). In this tightening middle period (pipe connection middle period), a seal portion 63 (a front ferrule-back ferrule seal portion) between the tapered surface 43a of the front ferrule 4 and the inner peripheral side tapered surface 52a of the back ferrule 5 is formed. (See FIG. 4). Along with this, a seal portion 64 (back ferrule-pipe seal portion) between the front end of the back ferrule 5 and the pipe P2 is formed (see FIG. 4). Specifically, the inner peripheral taper surface 52a is pressed against the taper surface 43a, and the tapered surface 43a made of an inclined surface generates a force that presses the front portion 52 of the back ferrule 5 toward the radially inner periphery. And by this pressing force, the front part 52 of the front part 52 bites into the pipe P2 (see FIG. 4). At this time, since the inclination angle γ1 of the inner peripheral side taper surface 52a is smaller than the inclination angle β2 of the taper surface 43a (see FIG. 2), the front portion 52 of the back ferrule 5 is pressed toward the inner side in the radial direction. You can strengthen your power.

  Furthermore, when the assembly of the coupling member 3 to the joint body 2 proceeds, not only the rear end of the front ferrule 4 but also a part of the back ferrule 5 is accommodated in the ferrule accommodating portion 27 (see FIGS. 4 and 5). Then, the outer peripheral side taper surface 52b of the back ferrule 5 contacts the taper surface 27c of the joint body 2, and the biting of the back ferrule 5 into the pipe P2 further proceeds (see FIG. 5). Along with this, a seal portion 65 (a joint body-back ferrule seal portion) for sealing between the joint body 2 and the back ferrule 5 is formed (see FIG. 5). Specifically, the outer peripheral side tapered surface 52b is pressed against the tapered surface 27c, and the tapered surface 27c formed of an inclined surface generates a force that presses the front portion 52 of the back ferrule 5 toward the radially inner peripheral side (FIG. 5). Then, by this pressing force, the front portion 52 of the front portion 52 of the back ferrule 5 further bites into the pipe P2, and a seal portion 65 is formed (see FIG. 5). Here, the movement of the front ferrule 4 toward the front side in the axial direction is not constrained. For this reason, the rear portion 43 of the front ferrule 4 is further pressed forward in the axial direction by the movement of the inner peripheral side tapered surface 52a of the back ferrule 5 to the front side in the axial direction accompanying the movement of the outer peripheral side tapered surface 52b to the front side in the axial direction. Will be. Then, by this pressing force, the biting of the front portion of the front portion 42 of the front ferrule 4 into the pipe P2 further proceeds (see FIG. 5). That is, as shown in FIG. 7, the front ferrule 4 is subjected to a pressing force even after the back ferrule 5 (the outer peripheral tapered surface 52b) contacts the joint body 2 (tapered surface 27c). The biting into the pipe P2 further proceeds by the pressing force. At this time, since the inclination angle γ2 of the outer peripheral taper surface 52b is larger than the inclination angle α3 of the taper surface 27c (see FIG. 2), the force for pressing the front portion 52 of the back ferrule 5 in the axial front side is increased. be able to.

  Thus, the pipe connection by the bite type pipe connection structure 1 of the present embodiment is performed. By this pipe connection, the bite type pipe connection structure 1 is formed with not only the seal parts 61 to 64 that the conventional double ferrule structure has but also a seal part 65 that seals between the joint body 2 and the back ferrule 5. (See FIGS. 5 and 6).

  Here, when there is no seal part 65, the leakage of the fluid from the inside of the pipe P2 in the bite type pipe connection structure 1 includes a leak path through the seal part 61, a leak path through the seal parts 62 and 63, and a seal. Caused by the leakage path through the parts 62,64. That is, when there is no seal part 65, since there are only two leakage paths in which the seal part is arranged in series with respect to the fluid leakage direction, the seal part 65 is passed through the seal part 61 in which the seal part is not arranged in series. There is a risk that fluid leakage from the leakage path increases. Further, when there is no seal portion 65, there are three places where the fluid leaks to the outside, so there is a risk that fluid leakage will increase.

  On the other hand, when there is the seal portion 65, the fluid leaks from the inside of the pipe P2 in the bite type pipe connection structure 1 through the leak path through the seal portions 61, 65 and the seal portions 62, 63, 65. And a leakage path through the seal portions 62 and 64. That is, when there is the seal portion 65, there are three leakage paths in which the seal portion is arranged in series with respect to the direction of fluid leakage. Can be reduced. Further, when there is the seal portion 65, the leak path through the seal portion 61 and the leak path through the seal portions 62, 63 are more downstream than the seal portions 61, 62, 63 in the fluid leakage direction. The seal portion 65 arranged at the position joins. For this reason, when the seal portion 65 is present, the number of locations where the fluid leaks to the outside is reduced by one compared to the case where the seal portion 65 is not present, thereby reducing fluid leakage. It has become.

  In some cases, the coupling member 3 assembled as described above is detached from the joint body 2 due to a request for relocation of the refrigeration apparatus, and then the coupling member 3 is assembled to the joint body 2 again. At the time of such reassembly, the ferrule is already deformed. For this reason, in the case of a normal double ferrule structure, even if the coupling member is reassembled to the joint body using a ferrule that has been deformed by being used for assembly, the front ferrule has a pressing force against the joint body. Almost no effect. If it does so, since the sealing performance between a front ferrule and piping will fall, there exists a possibility that the reliability with respect to the leakage of a fluid may be impaired significantly.

  On the other hand, in the bite type pipe connection structure 1, as described above, the seal portion 65 is formed, and the movement of the front ferrule 4 toward the front side in the axial direction is not restricted. Even after the back ferrule 5 comes into contact with the joint body 2, a pressing force acts on the front ferrule 4. For this reason, even when it is a case where the coupling member 3 is reassembled to the joint main body 2 using the ferrules 4 and 5 that have been deformed by being used for assembly, a pressing force can be applied to the front ferrule 4 ( (See FIG. 8). Thereby, the biting of the front ferrule 4 into the pipe P2 can be advanced, and the reliability against fluid leakage can be ensured.

<Features>
Next, the features of the bite type pipe connection structure 1 of the present embodiment configured as described above will be described.

(A)
In the bite type pipe connection structure 1, as described above, the downstream side of the seal portion 61 (the joint body-front ferrule seal portion) and the seal portion 63 (the front ferrule-back ferrule seal portion) with respect to the fluid leakage direction. A seal portion 65 (a seal portion between the joint main body and the back ferrule) that seals between the joint main body 2 and the back ferrule 5 is formed at the position.

  Thereby, in the bite type pipe connection structure 1, the fluid leaking through the seal portion 61 and the fluid leaking through the seal portion 63 merge to reach the seal portion 65. For this reason, the fluid leaking through the seal part 61 is sealed in the seal part 65 arranged in series with respect to the fluid leak direction, and leakage of the fluid to the outside is suppressed. Further, the fluid leaking through the seal portion 63 is also sealed at the seal portion 65 arranged in series with respect to the fluid leakage direction, and the leakage of the fluid to the outside is suppressed. In addition, since the seal portion 65 is common to the seal portion 61 and the seal portion 63, the number of locations where fluid leaks to the outside is reduced by one as compared with the conventional double ferrule structure. That is, in the bite type pipe connection structure 1, since the seal portions are arranged in series and the number of places where the fluid leaks to the outside can be reduced, the reliability against fluid leakage can be improved.

(B)
In the bite type pipe connection structure 1, as described above, the cam surface 27a (joint main body-front ferrule pressing surface) bites into the pipe P2 of the front ferrule 4, and between the front ferrule 4 and the pipe P2. The seal part 62 and the seal part 61 (the joint body-front ferrule seal part) are formed. Further, the taper surface 43a (front ferrule-back ferrule pressing surface) causes the back ferrule 5 to bite into the pipe P2, and the seal portion 64 and the seal portion 63 (front ferrule) between the back ferrule 5 and the pipe P2. -A seal part between back ferrules) is formed. Moreover, the taper surface 27c (joint body-back ferrule pressing surface) further advances the biting of the back ferrule 5 into the pipe P2, and forms the seal portion 65 (joint body-back ferrule seal portion).

  Thereby, in the bite type pipe connection structure 1, since both the ferrules 4 and 5 can bite into the pipe P <b> 2 reliably and the seal portion 65 can be formed, the reliability against fluid leakage can be improved. it can.

(C)
In the bite type pipe connection structure 1, as described above, the joint body 2 includes the ferrule housing portion 27 that houses the front ferrule 4. The ferrule housing portion 27 forms a seal portion 61 (a joint body-front ferrule seal portion) with the front ferrule 4. The ferrule housing part 27 further houses a part of the back ferrule 5, and forms a seal part 65 (a joint body-back ferrule seal part) with the back ferrule 5.

  Thereby, in the bite type pipe connection structure 1, in the ferrule housing part 27, leakage of fluid from between the front ferrule 4 and the joint body 2 and leakage of fluid from between the front ferrule 4 and the back ferrule 5 are prevented. Can be suppressed.

(D)
In the bite type pipe connection structure 1, the outer diameter Db of the back ferrule 5 is larger than the outer diameter Df of the front ferrule 4 as described above. The ferrule housing portion 27 is between the back ferrule 5 and the seal portion 61 (sealing portion between the joint main body and the front ferrule) and the seal portion 63 (sealing portion between the front ferrule and the back ferrule) on the radially outer side. A seal portion 65 (a joint body-back ferrule seal portion) is formed.

  Thereby, in the bite type pipe connection structure 1, by making the outer diameter of the back ferrule 5 larger than the outer diameter of the front ferrule 4, the seal portion 65 is placed at a position on the radially outer peripheral side of the other seal portions 61 and 63. Can be formed.

(E)
In the bite type pipe connection structure 1, as described above, in the state before the coupling member 3 is assembled to the joint main body 2, the ferrule housing part 27 has a fastening direction that is a direction in which the coupling member 3 is assembled to the joint main body 2. The rear end of the accommodated front ferrule 4 is located behind the ferrule accommodating portion 27.

  Thereby, in the bite type pipe connection structure 1, when the coupling member 3 is assembled to the joint body 2, first, the rear end of the front ferrule 4 is housed in the ferrule housing portion 27 and the seal portion 61 (joint The main body-front ferrule seal portion) is formed and the front ferrule 4 is bitten into the pipe P2. Then, when the biting of the front ferrule 4 into the pipe P2 proceeds, the formation of the seal portion 63 (front ferrule-back ferrule seal portion) and the biting of the back ferrule 5 into the pipe P2 are performed. Furthermore, when the assembly of the coupling member 3 to the joint body 2 proceeds, not only the rear end of the front ferrule 4 but also a part of the back ferrule 5 is accommodated in the ferrule accommodating portion 27. Then, the back ferrule 5 comes into contact with the tapered surface 27c (joint body-back ferrule pressing surface) of the joint main body 2, and the biting of the back ferrule 5 into the pipe P2 further proceeds, and the seal portion 65 (joint body-back A seal part between ferrules) is formed.

  Thus, in the bite type pipe connection structure 1, between the joint body 2 and the pipe P2 and the front ferrule 4, between the front ferrule 4 and the pipe P2 and the back ferrule 5, and between the joint body 2 and the back ferrule 5, The seal between the members can be performed in the order of between the two.

(F)
In the bite type pipe connection structure 1, as described above, the cam surface 27a (joint body-front ferrule pressing surface), the taper surface 43a (front ferrule-back ferrule pressing surface), and the taper surface 27c (joint body-back ferrule). The pressing surface) forms an inclined surface that decreases in diameter toward the front side with respect to the fastening direction.

  Accordingly, in the bite type pipe connection structure 1, when the assembly of the coupling member 3 to the joint body 2 proceeds until the seal portion 65 (the joint body-back ferrule seal portion) is formed, the front ferrule is connected via the back ferrule 5. The ferrule 4 is further pressed toward the fastening direction. For this reason, in the bite type pipe connection structure 1, the biting of the front ferrule 4 into the pipe P <b> 2 further proceeds even after the biting into the pipe P <b> 2 of the back ferrule 5 is started. . Further, even when the coupling member 3 is reassembled to the joint body 2 using the ferrules 4 and 5 that have been deformed by being used for assembling, the biting of the front ferrule 4 into the pipe P2 can be advanced. it can.

  Thus, in the bite type pipe connection structure 1, it is possible to make it difficult for the front ferrule 4 to bite into the pipe P <b> 2, and even when the coupling member 3 is assembled to the joint body 2 again, fluid leakage Can be ensured.

<Modification 1>
In the bite type pipe connection structure 1 (see FIGS. 1 to 9) of the above-described embodiment, the coupling member 3 and the back ferrule 5 may be configured to be temporarily assembled.

  As shown in FIGS. 9 to 14, the bite type pipe connection structure 1 of this modification is different from the above embodiment in the configuration of the coupling member 3 and the back ferrule 5. For this reason, in the following description, it demonstrates centering around the structure of the back ferrule 5 and the coupling member 3, and description about structures other than the back ferrule 5 and the coupling member 3 is abbreviate | omitted.

  As in the above embodiment, the coupling member 3 is a metal member such as brass, and includes a base portion 31 in which the insertion port 32 and the pressing surface 34 are formed, and a fastening portion 33 in which the screw portion 33a is formed. Have. In the present modification, a temporary assembly engaging portion 35 for allowing the back ferrule 5 and the coupling member 3 to be temporarily assembled is further formed on the front portion of the base portion 31. The temporary assembly engaging portion 35 is located on the front side of the pressing surface 34 and is located on the rear side of the screw portion 33a. The temporary assembly engaging portion 35 mainly has a temporary assembly protrusion 36 and a temporary assembly enlarged diameter portion 37. The temporary assembly protrusion 36 is an annular portion that protrudes toward the radially inner peripheral side at a position in front of the pressing surface 34. The inner peripheral surface of the temporarily assembled projecting portion 36 has an inclined surface 36a whose diameter increases toward the front side. The inclined surface 36 a is for facilitating press-fitting of the temporarily assembled projecting portion 57 formed on the rear portion 53 of the back ferrule 5. The temporary assembly enlarged diameter portion 37 has a larger inner diameter than the temporary assembly protrusion 36 at a position on the rear side of the temporary assembly protrusion 36, that is, a position between the pressing surface 34 and the temporary assembly protrusion 36 in the axial direction. Part. The temporary assembly enlarged diameter portion 37 is for holding the temporary assembly protrusion 57 inserted through the temporary assembly protrusion 36. Here, the inner diameter of the temporary assembly protruding portion 36 is Dcn1, and the inner diameter of the temporary assembly enlarged diameter portion 37 is Dcn2 (see FIG. 11).

  The back ferrule 5 is a metal member such as brass, as in the above embodiment, and a pipe through hole 51 is formed in the axial center portion thereof. In addition, a tapered surface 52 a and a tapered surface 52 b are formed in the front portion 52 constituting the front portion of the back ferrule 5. In this modification, a temporary assembly engaging portion 56 for allowing the back ferrule 5 and the coupling member 3 to be temporarily assembled is further formed in the rear portion 53 constituting the rear portion of the back ferrule 5. Yes. The temporary assembly engaging portion 56 can be engaged with the temporary assembly engaging portion 35 of the coupling member 3. The temporary assembly engaging portion 56 mainly has a temporary assembly protrusion 57. The temporary assembly protrusion 57 is an annular portion that protrudes toward the radially outer peripheral side. The cross-sectional shape along the axial direction of the temporarily assembled projecting portion 57 is an arc shape. In other words, the outer peripheral surface of the temporarily assembled projecting portion 57 is such that the portion in the vicinity of the center in the axial direction protrudes most radially outward, and the diameter decreases toward the front side and the rear side from this portion. It has a surface. The temporary assembly protrusion 57 comes into contact with the pressing surface 34 of the coupling member 3 when the coupling member 3 is assembled to the joint body 2. Here, the outer diameter of the temporary assembly protrusion 57, that is, the maximum outer diameter Dn of the temporary assembly engaging portion 56 is larger than the inner diameter Dcn1 of the temporary assembly protrusion 36 of the coupling member 3, and the temporary assembly enlarged diameter portion. It is smaller than the inner diameter Dcn2 of 37 (see FIG. 11).

  The back ferrule 5 and the coupling member 3 configured as described above are configured to be temporarily assembled with each other in a state before the coupling member 3 is assembled to the joint body 2 (see FIG. 10). Here, the back ferrule 5 and the coupling member 3 relate the temporary assembly engagement portion 56 formed at the rear portion 53 of the back ferrule 5 and the temporary assembly engagement portion 35 formed at the base 31 of the connection member 3. By combining, temporary assembly is performed so that the axial movement and radial movement of each other are limited. More specifically, the rear part 53 of the back ferrule 5 is temporarily assembled by being pressed against the base 31 of the coupling member 3 in a state where the axis of the back ferrule 5 and the axis of the coupling member 3 are aligned. It has become so. That is, when the temporary assembly protrusion 57 is pressed against the inclined surface 36a of the temporary assembly protrusion 36, the temporary assembly protrusion 36 is deformed so that its diameter is slightly increased, and the temporary assembly protrusion 57 is slightly increased. Deforms to reduce diameter. Due to the deformation of the temporary assembly protrusions 36 and 57, the temporary assembly protrusion 57 is press-fitted through the temporary assembly protrusion 36 and inserted into the temporary assembly enlarged diameter portion 37. And after the temporary assembly protrusion part 57 is inserted in the temporary assembly enlarged diameter part 37, the temporary assembly protrusion parts 36 and 57 return to the state before the deformation or the state before the deformation by the buckling after the deformation, The temporary assembly protrusion 57 is held in a state of being inserted into the temporary assembly enlarged diameter portion 37. Thereby, the front ferrule 4, the back ferrule 5, and the coupling member 3 can be coupled to the joint body 2 in a temporarily assembled state.

  Next, a pipe connection method using the bite type pipe connection structure 1 of the present modification configured as described above will be described.

  Prior to connecting the pipe P2, the joint body 2 is attached to the pipe P1 derived from the connected device. Next, connection of the piping P2 by the bite type pipe connection structure 1 is performed by first inserting the piping P2 to be connected to the insertion port 32 of the coupling member 3 and mounting the coupling member 3 on the piping P2. Next, the pipe P2 is inserted into the pipe through holes 31, 41, 51 of the back ferrule 5 and the coupling member 3 that are temporarily assembled together with the front ferrule 4, and the front ferrule 4, the back ferrule 5, and the coupling member 3 are piped. Exterior to P2. Then, the front end portion of the pipe P2 is inserted into the insertion port 25 of the joint body 2 so that the pipe P2 is in contact with the stepped portion 26, and the coupling member 3 is temporarily attached to the joint body 2 with the back ferrule 5 temporarily assembled. Threaded onto. And the sealing parts 61-65 are formed by fastening the coupling member 3 to the joint main body 2 similarly to the said embodiment (refer FIG. 14). Here, when the front portion 52 of the front portion 52 bites into the pipe P <b> 2, the rear portion 53 of the back ferrule 5 is pressed toward the radially inner peripheral side by the pressing surface 34 of the coupling member 3. For this reason, in the back ferrule 5 temporarily assembled to the coupling member 3, the temporary assembly protrusion 57 is deformed. However, if the protrusion is deformed unevenly in the circumferential direction, the back ferrule 5 is eccentrically pressed and fluid leakage occurs. Connected. However, in this modification, since the cross-sectional shape along the axial direction of the temporary assembly protrusion 57 is an arc shape, the temporary assembly protrusion 57 is difficult to be deformed and is prevented from being unevenly deformed in the circumferential direction. .

  Also in the bite type pipe connection structure 1 of this modification, not only the seal portions 61 to 64 but also the seal portion 65 (a joint body-back ferrule seal portion) is formed as in the above embodiment. As a result, all the seal portions are arranged in series and the number of places where the fluid leaks to the outside can be reduced, so that the reliability against fluid leakage can be improved.

  Moreover, in the bite type pipe connection structure 1 of the present modification, as described above, the back ferrule 5 and the coupling member 3 can be coupled to the joint body 2 in a temporarily assembled state. Yes.

  Thereby, in the bite type pipe connection structure 1 of this modification, the workability when the coupling member 3 is assembled to the joint body 2 can be improved.

  Further, in the bite type pipe connection structure 1 of this modification, as described above, the axial movement and the radial movement of each other are restricted by the engagement of the temporary assembly engaging portion 56 and the temporary assembly engaging portion 35. In this state, the coupling member 3 and the back ferrule 5 can be temporarily assembled.

  Thereby, in the bite type pipe connection structure 1 of this modification, the back ferrule 5 and the coupling member 3 are in a state where the axial movement and the radial movement of each other are restricted by the engagement between the back ferrule 5 and the coupling member 3. Can be temporarily assembled.

  Further, in the bite type pipe connection structure 1 of the present modification, the temporary assembly engagement portion 56 is a temporary assembly protrusion 57 that protrudes toward the radially outer peripheral side. The temporary assembly engaging portion 35 includes a temporary assembly protrusion portion 36 that protrudes toward the radially inner peripheral side, and a temporary assembly enlarged diameter portion 37 that has a larger inner diameter than the temporary assembly protrusion portion 36. The temporary assembly engaging portion 56 is inserted and held in the temporary assembly enlarged diameter portion 37 via the temporary assembly protrusion 36. For this reason, the coupling member 3 and the back ferrule 5 are engaged and temporarily assembled in a state where they are overlapped in the axial direction.

  Thereby, in the bite type pipe connection structure 1 of this modification, it is possible to make it difficult to release the temporarily assembled state of the coupling member 3 and the back ferrule 5.

  Further, in the bite type pipe connection structure 1 of this modification, as described above, the temporary assembly engaging portion 56 is press-fitted into the temporary assembly protrusion 36 and inserted into the temporary assembly enlarged diameter portion 37.

  Thereby, in the bite type pipe connection structure 1 of the present modification, the back ferrule 5 and the coupling member 3 can be temporarily assembled by pressing each other. In addition, as a temporary assembly structure of the back ferrule 5 and the coupling member 3, instead of a structure in which the temporary assembly protrusion 57 is press-fitted into the temporary assembly protrusion 36 and inserted into the temporary assembly enlarged diameter portion 37, each protrusion A temporary assembly structure may be employed in which a screw or a spline is provided and engaged.

  Further, in the bite type pipe connection structure 1 of the present modification, as described above, the cross-sectional shape along the axial direction of the temporary assembly engaging portion 56 is an arc shape.

  Thereby, in the bite type pipe connection structure 1 of the present modification, the temporary assembly engaging portion 56 is prevented from being irregularly deformed in the circumferential direction, thereby contributing to suppression of fluid leakage. Note that the cross-sectional shape along the axial direction of the temporary assembly engaging portion 56 may be a substantially triangular cross-sectional shape, but here, in consideration of irregular deformation in the circumferential direction as described above and the risk of fluid leakage. Thus, the shape is an arc.

<Modification 2>
In the bite type pipe connection structure 1 according to the embodiment and the modification 1 thereof, the leakage of fluid is suppressed by the five seal portions 61 to 65 (see FIGS. 6 and 14).

  In the bite type pipe connection structure 1 having such five seal portions 61 to 65, in order to further improve the reliability against fluid leakage, as shown in FIG. 15, a gap between the joint body 2 and the pipe P <b> 2 is provided. You may make it provide the O-ring type seal part 66 to seal. Here, an annular groove 28 is formed in a portion of the joint body 2 on the front side of the cam surface 27 a of the shaft portion 23, and an O-ring 67 is fitted into the groove 28.

  Thereby, in the bite type pipe connection structure 1 of this modification, since the seal portion is further arranged in series with respect to the fluid leakage direction, the reliability against fluid leakage can be further improved. In FIG. 15, the O-ring type seal portion 66 is provided in the configuration of the first modification. However, in the above embodiment, the O-ring type seal portion 66 may be provided.

<Modification 3>
In the bite type pipe connection structure 1 according to the embodiment and the modifications 1 and 2 thereof, the ferrule housing portion 27 of the joint body 2 includes the cam surface 27a (joint body-front ferrule pressing surface) and the tapered surface 27c (joint body-back ferrule). A cylindrical surface 27b is provided between the pressing surface and the pressing surface. The front ferrule 4 is also formed on the rear side of the tapered surface 42a so that a flat surface whose diameter does not change in the front-rear direction is along the cylindrical surface 27b. However, as shown in FIGS. 16 and 17, the cylindrical surface 27b of the joint body 2 may be omitted, and the axial dimension of the flat surface of the front ferrule 4 along this may be shortened.

  Thereby, in the bite type pipe connection structure 1 of the present modification, the axial dimension can be reduced. 16 and 17, the cylindrical surface 27b of the joint body 2 is omitted in the configuration of the modified example 1, and the axial dimension of the flat surface of the front ferrule 4 along this is shortened. However, the present invention is not limited to this, and in the configuration of the above-described embodiment or modification 2, the cylindrical surface 27b of the joint body 2 may be omitted, and the flat surface of the front ferrule 4 along this may be shortened. .

<Modification 4>
In the said embodiment and its modifications 1-3, although the piping P1 is attached to the coupling main body 2 by brazing etc. and only the piping P2 side is comprised by the bite type pipe connection structure 1, it is limited to this. It is not something.

  For example, as shown in FIG. 18, a double union structure in which a bite type pipe connection structure 1 similar to the pipe P2 side is provided on the pipe P1 side of the joint body 2 may be used.

  Moreover, in this case, the outer shape of the substantially hexagon nut shape is omitted in order to hold it with a general-purpose fastening tool formed on the base portion 21 of the joint body 2 of the above embodiment and its modifications 1 to 2. The coupling member 3 may be fastened to the joint body 2 by gripping with the fastening tool. Further, most of the joint body 2 may be covered with the coupling member 3. Thereby, the axial direction dimension of the bite type pipe connection structure 1 can be shortened. FIG. 18 shows the configuration of the first modification having a double union structure, but is not limited to this, and the configuration of the above embodiment and the second and third modifications has a double union structure. It may be.

<Modification 5>
In the bite type pipe connection structure 1 of the above embodiment and its modifications 1 to 4, after the coupling member 3 has a substantially hexagonal nut shape, the coupling member 3 is fastened to the joint body 2 and assembled. However, the coupling member 3 is structured to be able to be held and loosened with a general-purpose fastening tool.

  In such a bite type pipe connection structure 1, after the coupling member 3 is fastened and assembled to the joint body 2, the coupling member 3 is loosened so that the coupling member 3 cannot be gripped by a general-purpose fastening tool. You may make it comprise so that it cannot do.

  For example, a double ferrule structure similar to that of the first modification is adopted, and after being assembled to the joint body 2, a tool hook held by a general-purpose fastening tool is cut from a fastening part that is screwed with the joint body 2. You may employ | adopt the coupling member 3 made to do.

  As shown in FIGS. 19 to 24, the bite type pipe connection structure 1 of the present modification is different from the first modification in the configuration of the joint body 2 and the coupling member 3. For this reason, in the following description, it demonstrates centering around the structure of the coupling main body 2 and the coupling member 3, and description about structures other than the coupling main body 2 and the coupling member 3 is abbreviate | omitted.

  The joint body 2 is a metal member such as brass and has a base 121. A socket portion 22 is formed on the front side of the base portion 121, and a cylindrical portion 123 and a shaft portion 23 are formed on the rear side of the base portion 121. A screw portion 123 a made of an internal thread for screwing the coupling member 3 is formed on the inner peripheral portion of the cylindrical portion 123. The shaft portion 23 is formed so as to protrude into the space on the inner peripheral side of the cylindrical portion 123. An annular space 125 is formed on the outer peripheral surface of the shaft portion 23 to adjust the strength of the shaft portion 23 when the pipe is connected. Further, a vent hole 125a for preventing internal freezing is formed in the outer peripheral portion of the annular space 125. The outer peripheral parts of the base part 121 and the cylindrical part 123 are formed in a substantially hexagonal nut shape so that they can be gripped by a general-purpose fastening tool. An insertion port 24 for inserting the pipe P <b> 1 is formed in the axial center portion from the socket portion 22 to the base portion 121. An insertion port 25 for inserting the pipe P <b> 2 is formed in the axial center portion from the shaft portion 23 to the base portion 121. Between the insertion port 24 and the insertion port 25 in the axial direction, a communication hole having a smaller diameter than that of the insertion port 24 and the insertion port 25 is formed, and the stepped portion 26 that restricts the axial movement of the pipes P1 and P2. Is formed. A cam surface 27a, a cylindrical surface 27b, and a tapered surface 27c similar to those of the first modification are formed at the tip portion of the shaft portion 23, that is, the rear end portion of the insertion port 25.

  The coupling member 3 is a metal member such as brass, and an insertion port 32 for inserting the pipe P2 is formed in the shaft center portion, and a radial cut is made so as to bisect the coupling member 3 in the front-rear direction. A disk-shaped slit 132 is formed. On the front side of the disc-shaped slit 132, a fastening portion 133 that is screwed with the joint body 2 is formed. On the rear side of the disc-shaped slit 132, a tool hanging portion 134 that is gripped by a general-purpose fastening tool is formed. . A screw portion 133 a made of a male screw that is screwed into the screw portion 123 a of the joint body 2 is formed on the outer peripheral portion of the fastening portion 133. The outer peripheral portion of the tool hook 134 is formed in a substantially hexagonal nut shape so that it can be gripped by a general-purpose fastening tool. And between the radial direction of the disk shaped slit 132 and the insertion port 32, the cutting part 136 which consists of a thin annular part which connects the fastening part 133 and the tool hook part 134 is formed. The cutting part 136 is designed to have a strength to be cut when the tightening torque of the tool hook part 134 is increased to the value when the pipe connection is completed. Here, the cutting part 136 is formed so that the thickness decreases toward the front side, and is cut in the vicinity of the fastening part 133. Further, the front side portion of the fastening portion 133 constitutes the base portion 31, and the pressing surface 34 and the temporary assembly engaging portion 35 similar to those of the first modification are formed. In addition, a plurality of (here, six) engagement holes 135 having a circular cross section and a predetermined depth in which the dedicated jig 107 can be engaged are formed in the rear portion of the fastening portion 133. . Further, a processing hole 137 for allowing the engagement hole 135 to be processed from the side of the tool hook 134 is formed in the tool hook 134 so as to face the engagement hole 135.

  Next, a pipe connection method using the bite type pipe connection structure 1 of the present modification configured as described above will be described.

  Prior to connecting the pipe P2, the joint body 2 is attached to the pipe P1 derived from the connected device. Next, connection of the piping P2 by the bite type pipe connection structure 1 is performed by first inserting the piping P2 to be connected to the insertion port 32 of the coupling member 3 and mounting the coupling member 3 on the piping P2. Next, the pipe P2 is inserted into the pipe through holes 31, 41, 51 of the back ferrule 5 and the coupling member 3 that are temporarily assembled together with the front ferrule 4, and the front ferrule 4, the back ferrule 5, and the coupling member 3 are piped. Exterior to P2. Then, the front end portion of the pipe P2 is inserted into the insertion port 25 of the joint body 2 so that the pipe P2 is in contact with the stepped portion 26, and the coupling member 3 is temporarily attached to the joint body 2 with the back ferrule 5 temporarily assembled. Threaded onto. And the sealing parts 61-65 are formed by fastening the coupling member 3 to the joint main body 2 similarly to the said modification 1. As shown in FIG. Then, when the formation of the seal portions 61 to 65 is completed and the tightening torque of the tool hook portion 134 is increased to the value at the completion of the pipe connection, the cutting portion 136 is cut and the tool hook portion 134 is connected to the fastening portion 133. (See FIG. 23).

  Thus, the pipe connection by the bite type pipe connection structure 1 of this modification is performed.

  Next, since the fastening part 133 fastened in the above state is cut by the tool hook part 134, no one can easily loosen the fastening part 133, but a dedicated jig as shown in FIG. By using 107, the fastening part 133 can be loosened.

  The dedicated jig 107 mainly has two base portions 171a and 171b having a shape obtained by dividing a hexagonal disk into two. The base portions 171a and 171b have nut portions 172a and 172b that form hexagonal nuts when they are coupled to each other. Two columnar engagement protrusions 175b that engage with engagement holes (not shown) of the base 171a are formed on the surface of the base 171b facing the base 171a. Semicircular holes 173a and 173b are formed in the center of the bases 171a and 171b. The inner diameters of the holes 173a and 173b are slightly larger than the outer diameter of the pipe P2. Three columnar engagement protrusions 174a and 174b that can be engaged with the engagement holes 135 of the fastening portion 133 are formed on the side surfaces of the base portions 171a and 171b, respectively.

  Then, the bases 171 a and 171 b of the dedicated jig 107 are coupled by the engagement holes and the engagement protrusions 175 b, and the engagement protrusions 174 a and 174 b are engaged with the engagement holes 135 of the fastening part 133. Then, by rotating the dedicated jig 107 with the nut parts 172a and 172b of the dedicated jig 107 with a general-purpose fastening tool, the screwing between the fastening part 133 and the joint body 1 can be loosened, and the pipe P2 can be removed. . According to this pipe connection release method, the pipe P2 can be removed without cutting the pipe P2.

  Also in the present modification, not only the seal portions 61 to 64 but also the seal portion 65 (a joint body-back ferrule seal portion) is formed as in the first modification. As a result, all the seal portions are arranged in series and the number of places where the fluid leaks to the outside can be reduced, so that the reliability against fluid leakage can be improved. In addition, after the coupling member 3 is fastened and assembled to the joint body 2, the coupling member 3 can be prevented from being loosened with a general-purpose fastening tool. In addition, although the example which employ | adopted the structure which cannot loosen the coupling member 3 after an assembly | attachment was demonstrated here on the assumption of the structure of the said modified example 1, it is not limited to this. For example, in the said embodiment and its modifications 2-4, you may employ | adopt the structure which cannot loosen the coupling member 3 after an assembly | attachment.

<Modification 6>
In the bite type pipe connection structure 1 of the modification 5, the cutting part 136 is cut when the tightening torque of the tool hook part 134 is increased to the value when the pipe connection is completed.

  However, since the change in tightening torque with respect to the rotation angle is gradual in the bite type pipe connection structure, there is a possibility that a large variation in cutting torque may occur depending on the strength of the material used, the dimensional tolerance of the member, and the like.

  Therefore, in this modification, as shown in FIGS. 25 to 27, a protrusion 138 protruding in the radial direction is provided on the rear side of the screw part 133 a of the fastening part 133. The protrusion 138 comes into contact with the end surface on the rear side of the cylindrical portion 123 of the joint body 2 immediately before the coupling member 3 is screwed into the joint body 2 and the tool hook portion 134 is cut from the fastening portion 133. Is formed. For this reason, after the rear end surface of the cylindrical portion 123 of the joint body 2 comes into contact with the protrusion 138, a tightening torque higher than the cutting torque acts on the tool hanging portion 134, and the tool hanging portion 134 is moved from the fastening portion 133. It is designed to be disconnected.

  Thereby, in this modification, it can respond also to the variation of the above cutting torques. In addition, although the example which provided the protrusion 138 in the structure of the modification 5 on the assumption of the structure of the said modification 1 was demonstrated here, it is not limited to this. For example, the protrusion 138 may be provided in the configuration of the fifth modification based on the above embodiment and the second to fourth modifications.

<Other embodiments>
As mentioned above, although embodiment of this invention was described based on drawing, specific structure is not restricted to the said embodiment and its modification, It can change in the range which does not deviate from the summary of invention.

  In the said embodiment and its modifications 1-4, although the screw part 23a of the coupling main body 2 is made into the external thread, and the screw part 33a of the coupling member 3 is made into the internal thread, it is not limited to this, The screw part 23a is made. A female screw may be used, and the screw portion 33a may be a male screw. Moreover, in the said modification 5 and 6, although the screw part 23a of the coupling main body 2 is made into the internal thread and the screw part 33a of the coupling member 3 is made into the external thread, it is not limited to this, The screw part 23a is made into the external thread. The screw portion 33a may be a female screw.

  Moreover, in the said modification 5 and 6, although the cutting part 136 is formed of the disk shaped slit 132 which has a cut | interruption of a radial direction so that the coupling member 3 may be divided into front and back, it is not limited to this. . For example, the cutting part 136 may be formed by a cylindrical slit having an axial cut so as to bisect the coupling member 3 inward and outward.

  Moreover, in the said embodiment and its modification, although metal materials, such as copper, are used as piping, and metal materials, such as brass, are used as a coupling main body, a coupling member, and a ferrule, it is limited to this. It is not a thing. For example, aluminum, stainless steel, resin, iron, or the like may be used as a pipe, a joint body, a coupling member, and a ferrule.

  The present invention can be widely applied to a bite type pipe connection structure using two ferrules.

1 Bite-type pipe connection structure 2 Joint body (
3 coupling member 4 front ferrule 5 back ferrule 27 ferrule housing portion 27a cam surface (joint body-front ferrule pressing surface)
27c Tapered surface (Fitting body-Back ferrule pressing surface)
43a Tapered surface (front ferrule-back ferrule pressing surface)
61 Sealing part (Fitting body-front ferrule sealing part)
63 Sealing part (front ferrule-back ferrule sealing part)
65 Seal (Fitting body-Back ferrule seal)
66 O-ring seal

Japanese Utility Model Publication No. 49-3111 JP 2006-207795 A JP 2005-337326 A JP-T-2001-520728

Claims (7)

The joint body (2), the coupling member (3) screwed and assembled to the joint body, and the joint body and the coupling member are formed separately and between the joint body and the coupling member. In a bite type pipe connection structure provided with a front ferrule (4) and a back ferrule (5) sandwiched between
The front ferrule forms a joint body-front ferrule seal portion (61) that seals between the joint body and the front ferrule with the joint body,
The back ferrule forms a front ferrule-back ferrule seal portion (63) that seals between the front ferrule and the back ferrule with the front ferrule, and between the joint body, A joint body-back that seals between the joint body and the back ferrule at a position downstream of the joint body-front ferrule seal part and the front ferrule-back ferrule seal part with respect to the fluid leakage direction. Forming a ferrule seal (65),
Bite type pipe connection structure (1). The front ferrule (4) generates a force that presses the back ferrule (5) radially inward when the coupling member (3) is assembled to the joint body (2). A pressing surface (43a),
The joint body includes a joint body-front ferrule pressing surface (27a) that generates a force that presses the front ferrule radially inward when the coupling member is assembled to the joint body; A joint body-back ferrule pressing surface (27c) that generates a force for pressing the back ferrule radially inward when assembled to the joint body;
The bite type pipe connection structure (1) according to claim 1. The joint body (2) has a ferrule housing part (27) for housing the front ferrule (4),
The ferrule housing portion forms the joint body-front ferrule seal portion (61) with the front ferrule,
The ferrule housing part further houses a part of the back ferrule (5), and forms the joint body-back ferrule seal part (65) with the back ferrule.
The bite type pipe connection structure (1) according to claim 2. The outer diameter of the back ferrule (5) is larger than the outer diameter of the front ferrule (4),
The ferrule housing part (27) is located between the back ferrule at a position on the radially outer side of the joint body-front ferrule seal part (61) and the front ferrule-back ferrule seal part (63). , Forming the joint body-back ferrule seal part (65),
The bite type pipe connection structure (1) according to claim 3. In the state before assembling the coupling member (3) to the joint body (2), the ferrule housing part (27) accommodates the coupling member with respect to a fastening direction that is a direction of assembling the coupling member to the joint body. The rear end of the front ferrule (4) is located on the rear side in the axial direction from the ferrule housing portion.
The bite type pipe connection structure (1) according to claim 3 or 4. The joint body-front ferrule pressing surface (27a), the front ferrule-back ferrule pressing surface (43a), and the joint body-back ferrule pressing surface (27c) move toward the front side with respect to the fastening direction. It has an inclined surface with a small diameter,
The bite type pipe connection structure (1) according to any one of claims 2 to 5. An O-ring type seal portion (66) is provided at a position upstream of the joint body-front ferrule seal portion (27a) with respect to the fluid leakage direction.
The bite type pipe connection structure (1) according to any one of claims 1 to 6.

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