JP2015155726A - Pipe connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe connection structure capable of constantly controlling the leakage direction of refrigerant from a loose joint section and recognizing the leakage direction in advance.

SOLUTION: A pipe connection structure connecting pipes filled with refrigerant heavier than air, comprises: a joint body having a tapered tip end surface portion formed on a tip end of a male screw section; a flare pipe having a flare inner surface portion of a flare section formed on one end and closely attachable to the tip end surface portion; and a flare nut in which a female screw portion, a main through-hole, and a nut inner surface portion abuttable on a flare outer surface portion of the flare pipe inserted into the main through-hole are formed. A sub through-hole penetrating the nut inner surface portion with an outside is formed in the flare nut separately from the main through-hole, and inside diameter of the main through-hole is adjusted in accordance with outside diameter of the flare pipe. In a state in which the flare nut is fastened to the joint body, the nut inner surface portion presses the flare outer surface portion to airtight, closely attach the flare inner surface portion to the tip end surface portion, and the flare outer surface portion airtight closes an opening of the nut inner surface portion of the sub through-hole.

COPYRIGHT: (C)2015,JPO&INPIT

Description

  The present invention relates to a pipe connection structure.

  In a conventional pipe connection structure, a joint body and a flare that is screwed to the joint body are used at a connection point of a copper pipe (pipe) of a refrigerant circuit provided in a cooler, a refrigerator, or other refrigeration apparatus. The joint body and the flare nut are both formed with a tapered surface, and the flare portion of the flare tube having a flared end is sandwiched between the tapered surfaces. A flare pipe joint that keeps hermeticity is known (see, for example, Patent Document 1).

Japanese Patent No. 3955973

  However, in the conventional pipe connection structure shown in Patent Document 1, when the joint portion is loosened for some reason, the leakage direction of the refrigerant is not constant. That is, for example, whether the refrigerant in the pipe leaks from the threaded surface of the joint body and the flare nut to the joint body side, or whether the refrigerant leaks from between the flare nut and the flare pipe to the flare pipe side, etc. I can't know about it in advance.

  Therefore, it is difficult to take measures in advance so as to appropriately handle the leaked refrigerant when the joint portion is loosened and the refrigerant in the pipe leaks from the joint portion.

  The present invention has been made to solve such a problem, and even if the fastening of the joint portion is loosened for some reason, the direction in which the refrigerant sealed in the refrigerant pipe leaks from the joint portion is controlled to be constant. It is possible to obtain a pipe connection structure capable of knowing in advance the leakage direction at that time.

  The pipe connection structure according to the present invention is a pipe connection structure for connecting refrigerant pipes filled with a refrigerant having an average molecular weight larger than that of air, wherein one end of the refrigerant pipe is connected to one end and a male screw is connected to the other end. A joint body in which a tapered tip surface portion is formed at the tip of the male screw portion, the other end of the refrigerant pipe is connected to one end, and a flare-like flare portion is formed at the other end. A flare tube whose flare inner surface part can be in close contact with the tip surface part, a female screw part corresponding to the male screw part, a main through hole through which the flare pipe passes, and the flare pipe passed through the main through hole A flare nut formed with an inner surface portion of a nut that can come into contact with a flare outer surface portion of the flare portion, and the flare nut has a sub-through hole that passes through the nut inner surface portion and the outer side of the flare nut. Before The inner through hole is formed separately from the main through hole, the inner diameter of the main through hole is adjusted according to the outer diameter of the flare pipe, and the inner surface of the nut is the flare nut in a state where the flare nut is fastened to the joint body. By pressing the outer surface portion, the flare inner surface portion is in airtight contact with the tip surface portion, and the flare outer surface portion airtightly closes the opening of the nut inner surface portion of the sub through hole.

  In the pipe connection structure according to the present invention, even if the joint part is loosened for some reason, the direction in which the refrigerant sealed in the refrigerant pipe leaks from the joint part can be controlled to be constant. There is an effect that the direction can be known in advance.

It is sectional drawing which shows the whole structure of the piping connection structure which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the coupling main body of the pipe connection structure which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the flare pipe | tube of the piping connection structure which concerns on Embodiment 1 of this invention. It is sectional drawing and the front view which show the flare nut of the piping connection structure which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the state before the fastening of the piping connection structure which concerns on Embodiment 1 of this invention. It is sectional drawing and the front view which show the state after the fastening of the piping connection structure which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the state which the fastening of the piping connection structure which concerns on Embodiment 1 of this invention loosened. It is sectional drawing, the front view, and top view which show the whole structure of the piping connection structure which concerns on Embodiment 2 of this invention. It is sectional drawing, the front view, and top view which show the whole structure of the piping connection structure which concerns on Embodiment 3 of this invention. It is sectional drawing, the front view, and top view which show the whole structure of the piping connection structure which concerns on Embodiment 4 of this invention.

  The present invention will be described with reference to the accompanying drawings. Throughout the drawings, the same reference numerals indicate the same or corresponding parts, and redundant description thereof will be simplified or omitted as appropriate.

Embodiment 1 FIG.
1 to 7 relate to Embodiment 1 of the present invention. FIG. 1 is a cross-sectional view showing the overall configuration of the pipe connection structure, FIG. 2 is a cross-sectional view showing a joint body of the pipe connection structure, and FIG. 4 is a sectional view and a front view showing a flare nut of the pipe connection structure, FIG. 5 is a sectional view showing a state before the pipe connection structure is fastened, and FIG. 6 is a pipe connection structure. FIG. 7 is a cross-sectional view and a front view showing a state after fastening, and FIG. 7 is a cross-sectional view showing a state where the fastening of the pipe connection structure is loosened.

As shown in FIG. 1, the pipe connection structure includes a joint body 10, a flare pipe 20, and a flare nut 30.
FIG. 2 shows the joint body 10. The joint body 10 is formed by fixing a joint part 12 to a base part 11. The joint part 12 is a cylindrical member. A main body through hole 13 is formed along the central axis of the joint portion 12 and the base portion 11. A male screw portion 14 is formed on the outer periphery of the joint portion 12. The male screw portion 14 is provided at one end of the joint body 10. A distal end surface portion 15 is formed at the end portion of the male screw portion 14 on the side opposite to the base portion 11. The distal end surface portion 15 has a tapered shape whose diameter gradually decreases as it approaches the end portion.

  A flare tube 20 is shown in FIG. The flare tube 20 is a hollow cylindrical member. A flare portion 21 is formed at one end of the flare tube 20. The flare portion 21 has a flare shape in which the diameter gradually increases as it approaches the end portion. The flare portion 21 has a flare inner surface portion 22 that continues from the inner peripheral surface of the flare tube 20 and a flare outer surface portion 23 that continues from the outer peripheral surface of the flare tube 20. The flare inner surface portion 22 of the flare portion 21 is formed in a shape that can be in close contact with the distal end surface portion 15 of the joint body 10.

  FIG. 4 shows the flare nut 30. The flare nut 30 is a member whose outer shape has a hexagonal column shape. A female thread portion 31 is formed on the inner periphery of the flare nut 30. The female thread portion 31 corresponds to the male thread portion 14 of the joint body 10. That is, the flare nut 30 of the flare nut 30 is aligned with the male screw portion 14 of the joint body 10, and the flare nut 30 is rotated with respect to the joint body 10. Can be made. The hexagonal columnar outer shape of the flare nut 30 is for allowing a tool such as a wrench or a spanner to be used when the flare nut 30 is rotated with respect to the joint body 10. The female thread portion 31 is arranged close to one end side of the flare nut 30.

  A main through hole 32 is formed in the flare nut 30. The main through hole 32 is provided on the other end side of the flare nut 30. The main through hole 32 is arranged along the central axis of the flare nut 30. The inner diameter of the main through hole 32 is adjusted according to the outer diameter of the flare tube 20. That is, a portion other than the flare portion 21 of the flare pipe 20 can be inserted into the main through hole 32 of the flare nut 30.

  A nut inner surface portion 33 is formed in a region from the outer edge of the main through hole 32 to the female screw portion 31 on the inner surface of the flare nut 30. The nut inner surface portion 33 is formed in a shape capable of coming into contact with the flare outer surface portion 23 of the flare portion 21 of the flare pipe 20 passed through the main through hole 32.

  The flare nut 30 is formed with a sub through hole 34 penetrating the nut inner surface portion 33 and the outer side of the flare nut 30. The sub through-hole 34 is provided separately from the main through-hole 32 while being adjacent to the outer edge of the main through-hole 32. Since the sub through hole 34 is provided adjacent to the outer edge of the main through hole 32, the opening provided on the outer side of the flare nut 30 out of the two openings of the sub through hole 34 is the side where the flare pipe 20 in the flare nut 30 extends. It can be said that it is provided.

  Next, the connection of the refrigerant pipes performed using the joint body 10, the flare pipe 20, and the flare nut 30 configured as described above will be described. Refrigerant gas is sealed in the refrigerant pipe to be connected. The refrigerant gas sealed in the refrigerant pipe is a flammable (more precisely, slightly flammable) gas. Further, this refrigerant gas has an average molecular weight larger than that of air (specific gravity relative to air is greater than 1), and has a property of sinking downward in the direction of gravity in air. Specific examples of the refrigerant include difluoromethane (CH2F2: R32), tetrafluoropropane (CF3CF = CH2: HFO-1234yf), propane (R290), propylene (R1270), ethane (R170), butane (R600), Isobutane (R600a), 1.1.1.2-tetrafluoroethane (C2H2F4: R134a), pentafluoroethane (C2HF5: R125), 1.3.3.3-tetrafluoro-1-propene (CF3-CH = (Mixed) refrigerant composed of one or more refrigerants selected from among CHF: HFO-1234ze) and the like can be used. Here, description will be continued assuming that R32 (difluoromethane: CH2F2) is sealed in the refrigerant pipe as a refrigerant.

  First, as shown in FIG. 5, the flare pipe 20 is passed through the flare nut 30. At this time, portions other than the flare portion 21 of the flare pipe 20 are passed from the inside to the outside of the flare nut 30. By doing in this way, the flare part 21 of the flare pipe | tube 20 is arrange | positioned inside the flare nut 30. FIG.

  In this state, the female thread portion 31 of the flare nut 30 is aligned with the male thread portion 14 of the joint body 10, and the flare nut 30 is rotated with respect to the joint body 10 in a predetermined direction (for example, clockwise). Then, due to the screw action of the male screw portion 14 and the female screw portion 31, the flare portion 21 is sandwiched between the tip surface portion 15 and the nut inner surface portion 33, and between the tip surface portion 15 and the nut inner surface portion 33. The distance gets closer.

  And it will be in the state shown in FIG. 6 by fully tightening the flare nut 30 with respect to the coupling main body 10. FIG. In the state where the flare nut 30 shown in FIG. 6 is fastened to the joint body 10, the nut inner surface portion 33 is in contact with the flare outer surface portion 23. The nut inner surface portion 33 presses the flare portion 21 toward the distal end surface portion 15, so that the flare inner surface portion 22 is tightly adhered to the distal end surface portion 15. Further, in this state, the flare outer surface portion 23 hermetically closes the opening of the nut inner surface portion 33 of the sub through hole 34.

  One end of the refrigerant pipe in which the above-described refrigerant is sealed is connected to the end of the joint body 10 on the side opposite to the male screw portion 14. Further, the other end of the refrigerant pipe filled with the refrigerant is connected to the end of the flare pipe 20 on the side opposite to the flare portion 21.

  In a state where the refrigerant pipes are connected to each other using the joint main body 10, the flare pipe 20, and the flare nut 30 shown in FIG. 6, the front end face portion 15 and the flare inner face portion 22 are brought into airtight contact with each other. The main body through hole 13 and the flare tube 20 are connected. Therefore, one refrigerant pipe is connected to the other refrigerant pipe through the main body through hole 13 and the flare pipe 20 of the joint main body 10 in an airtight manner. For this reason, it is possible for the encapsulated refrigerant to flow from one refrigerant pipe to the other refrigerant pipe without leaking at the connecting portion of the joint.

  A case where the fastening state between the flare nut 30 and the joint body 10 thus connected has been loosened for some reason will be described with reference to FIG. When the fastening state between the flare nut 30 and the joint body 10 is loosened, the force by which the nut inner surface portion 33 presses the flare portion 21 against the distal end surface portion 15 is weakened.

  For this reason, first, the adhesion between the flare inner surface portion 22 and the tip surface portion 15 is reduced, and the air pressure between the flare inner surface portion 22 and the tip surface portion 15 is reduced by the pressure of the refrigerant flowing inside the main body through hole 13 and the flare pipe 20. Torn. When the airtightness between the flare inner surface portion 22 and the front end surface portion 15 is broken, the refrigerant flowing inside the main body through-hole 13 and the flare pipe 20 is flare nut from the gap formed between the flare inner surface portion 22 and the front end surface portion 15. 30 flows into the interior space.

  Further, when the fastening state between the flare nut 30 and the joint body 10 is loosened and the force by which the nut inner surface portion 33 presses the flare portion 21 against the distal end surface portion 15 is weakened, the sub-penetration that has been airtightly closed by the flare outer surface portion 23. The opening of the nut inner surface portion 33 of the hole 34 is opened with respect to the internal space of the flare nut 30. Then, the internal space of the flare nut 30 is connected to the outside of the flare nut 30 through the sub through hole 34.

  Therefore, the refrigerant that has flowed into the internal space of the flare nut 30 from the gap formed between the flare inner surface portion 22 and the tip surface portion 15 is discharged to the outside of the flare nut 30 through the sub through hole 34. .

  As described above, when the joint portion is loosened due to unforeseen circumstances, the refrigerant does not leak from between the flare nut 30 and the joint body 10 to the joint body 10 side. It leaks from the sub through hole 34 to the flare tube 20 side. Therefore, even if the joint portion is unexpectedly loosened, the direction in which the refrigerant sealed in the refrigerant pipe leaks from the joint portion is always constant, and the leakage direction at that time can be known in advance.

  For this reason, when the joint part is loosened due to an unexpected situation and the refrigerant in the pipe leaks from the joint part, measures to properly handle the leaked refrigerant, i.e., the leaked refrigerant is more retained. It is difficult to take measures that are difficult or easier to diffuse.

  Specifically, a case is considered in which refrigerant pipes filled with a refrigerant having an average molecular weight larger than that of air as described above are connected. In this case, the refrigerant in the pipe has a property of sinking downward in the direction of gravity in the air. Therefore, when the refrigerant gas leaks from the joint portion, the leaked refrigerant gas flows on the floor surface. In particular, when the leaked part is close to the floor and close to the floor surface, or when the direction of the refrigerant jetting from the leaked part is vertically downward, the leaked refrigerant is placed on the floor surface from below. It concentrates as it gradually accumulates upward.

  Therefore, when the refrigerant pipe is passed in the horizontal direction, as shown in FIG. 6, with the flare nut 30 fastened to the joint body 10, the sub through hole 34 is gravity as viewed from the central axis of the flare nut 30. It is arranged on the upper side of the direction. When the flare nut 30 is loosened, if the looseness is slight, the amount of rotation of the flare nut 30 relative to the joint body 10 is considered to be small.

  Therefore, even when the flare nut 30 is loosened, it may be considered that the sub through hole 34 is disposed substantially on the upper side in the gravitational direction when viewed from the central axis of the flare nut 30 (in FIG. 7, the explanation is made). For the sake of convenience, the degree of looseness of the flare nut 30 relative to the joint body 10 is exaggerated). For this reason, it is possible to dispose the leaked portion from the floor by disposing the leaked refrigerant to the outside, that is, the sub through hole 34 as far as possible in the vertical direction.

  Further, in this case, the flare pipe 20 is present vertically below the leakage portion (sub through hole 34). For this reason, the flare pipe 20 can inhibit the refrigerant leaking from the sub through hole 34 from flowing directly downward vertically. Therefore, even if the flare nut 30 is unexpectedly loosened and the refrigerant leaks, the leaked refrigerant is less likely to stay and can be more easily diffused.

  Further, when the refrigerant pipe is extended in the vertical direction, although not shown, the joint body 10 and the flare pipe 20 are arranged so that the joint body 10 is disposed on the vertically lower side and the flare pipe 20 is disposed on the vertically upper side. The orientation of the flare nut 30 may be determined. By doing in this way, even if the flare nut 30 is loosened, the refrigerant leaked from the pipe is ejected from the sub through hole 34 toward the flare pipe 20 side, that is, vertically upward.

  For this reason, even if the flare nut 30 is unexpectedly loosened and the refrigerant leaks, the leaked refrigerant is less likely to stay and diffuse more by jetting the leaked refrigerant vertically upward from the sub through hole 34. It can be made easier.

  The pipe connection structure configured as described above is a pipe connection structure for connecting refrigerant pipes in which a refrigerant having an average molecular weight larger than that of air is sealed, and one end of the refrigerant pipe is connected to one end and the other end is male. A threaded portion 14 is formed, the joint body 10 having a tapered distal end surface portion 15 formed at the distal end of the male threaded portion 14, the other end of the refrigerant pipe connected to one end, and a flared flare portion 21 at the other end. The flare tube 20 is formed and the flare inner surface portion 22 of the flare portion 21 can be in close contact with the front end surface portion 15, the female screw portion 31 corresponding to the male screw portion 14, the main through hole 32 through which the flare tube 20 passes, and the And a flare nut 30 formed with a nut inner surface portion 33 capable of contacting the flare outer surface portion 23 of the flare portion 21 of the flare tube 20 passed through the main through hole 32.

  The flare nut 30 is formed with a sub through-hole 34 penetrating the nut inner surface portion 33 and the outer side of the flare nut 30 separately from the main through-hole 32. Further, the inner diameter of the main through hole 32 is adjusted in accordance with the outer diameter of the flare tube 20. Then, in a state where the flare nut 30 is fastened to the joint main body 10, the nut inner surface portion 33 presses the flare outer surface portion 23, whereby the flare inner surface portion 22 is tightly adhered to the tip surface portion 15 and the flare outer surface portion 23. However, the opening of the nut inner surface portion 33 of the sub through hole 34 is airtightly closed.

  For this reason, the airtightness in the joint portion can be appropriately maintained in a sufficiently fastened state, and even if the joint portion is loosened for some reason, the refrigerant sealed in the refrigerant pipe leaks from the joint portion. The direction can be controlled to be constant, and the leakage direction at that time can be known in advance.

  Therefore, in particular, when a refrigerant having a larger average molecular weight than the air in the refrigerant pipe is enclosed, measures are taken in advance so that the refrigerant leaking from the loose joint part is less likely to stay or more easily diffuse. It is possible to reduce the possibility that a region in which the concentration of the leaked refrigerant becomes a certain level or more is formed.

Embodiment 2. FIG.
FIG. 8 relates to Embodiment 2 of the present invention, and is a cross-sectional view, a front view, and a top view showing the overall configuration of the pipe connection structure.
As shown in FIG. 8, in the second embodiment described here, a sub through hole position display 35 is provided on the outer surface of the flare nut 30. The sub through hole position display 35 indicates a position where the sub through hole 34 in the flare nut 30 is formed.

Here, the sub through-hole position display 35 is an arrow type. The sub through hole position display 35 is disposed on the outer surface of the flare nut 30 on the side where the sub through hole 34 is provided when viewed from the central axis of the flare nut 30. The arrow of the sub through hole position display 35 indicates the direction in which the opening of the sub through hole 34 outside the flare nut 30 is present.
Other configurations are the same as those in the first embodiment, and detailed description thereof is omitted.

  As described in the first embodiment, for example, when the refrigerant pipe is passed in the horizontal direction, the sub through-hole 34 extends from the central axis of the flare nut 30 with the flare nut 30 fastened to the joint body 10. If the joint portion is loosened due to an unexpected situation and the refrigerant in the pipe leaks from the joint portion due to an unexpected situation, the leaked refrigerant is less likely to stay, or It is very effective as a measure that makes it easier to spread.

  Further, for example, when the refrigerant pipe is extended in the vertical direction, the joint body 10 is arranged vertically downward and the flare pipe 20 is arranged vertically upward. When the refrigerant in the pipe leaks loosely from the joint portion, it is very effective as a countermeasure to make the leaked refrigerant less likely to stay or more easily diffuse.

  According to the configuration of the second embodiment, the operator confirms the sub through hole position display 35 provided on the outer surface of the flare nut 30, so that the position and direction of the sub through hole 34 in the flare nut 30 are confirmed. Can be easily known. Therefore, when the flare nut 30 is fastened to the joint body 10, the secondary through hole 34 can be easily adjusted so as to be in a desired position, and the above-described measures can be taken reliably, and the The workability at the time can be improved.

Embodiment 3 FIG.
FIG. 9 relates to Embodiment 3 of the present invention, and is a cross-sectional view, a front view, and a top view showing the overall configuration of the pipe connection structure.
As shown in FIG. 9, in the third embodiment described here, a nut orientation indicator 36 is provided on the outer surface of the flare nut 30. The nut orientation indicator 36 is a flare nut for allowing the sub through hole 34 to be disposed on the upper side in the gravity direction when viewed from the central axis of the flare nut 30 in a state where the flare nut 30 is fastened to the joint body 10. 30 orientations are shown.

  Here, the nut orientation display 36 has an arrow shape. The nut orientation indicator 36 is disposed on the outer surface of the flare nut 30 at a position of approximately 90 degrees with respect to the side on which the sub through hole 34 is provided as viewed from the central axis of the flare nut 30. The arrow of the nut orientation display 36 is directed to the side opposite to the side where the sub through hole 34 is provided when the tip end side of the arrowhead is viewed from the central axis of the flare nut 30.

Here, not only the nut orientation display 36 is provided on the flare nut 30 but also the body orientation indication 16 is provided on the joint body 10. The main body orientation indicator 16 is provided on the outer surface of the joint main body 10. Here, the main body orientation display 16 is also of an arrow shape like the nut orientation display 36. The main body direction display 16 is adjusted so that the arrow of the main body direction display 16 is directed in the same direction as the gravity direction (that is, vertically downward) when the joint main body 10 is installed.
Other configurations are the same as those in the first embodiment, and detailed description thereof is omitted.

  As described in the first embodiment, when the refrigerant pipe is passed in the horizontal direction, the sub through hole 34 is viewed from the central axis of the flare nut 30 with the flare nut 30 fastened to the joint body 10. If the joint part is loosened due to an unexpected situation and the refrigerant in the pipe leaks from the joint part due to an unexpected situation, it is more difficult for the leaked refrigerant to stay, or more It is very effective as a measure to make it easy to spread.

  According to the configuration of the third embodiment, when the flare nut 30 is fastened to the joint main body 10, the operator displays the nut orientation indicator 36 provided on the outer surface of the flare nut 30 vertically downward (same as the gravity direction). The secondary through hole 34 can be easily adjusted so as to be arranged on the upper side in the gravity direction when viewed from the central axis of the flare nut 30. Therefore, the measures as described above can be taken reliably and the workability at that time can be improved.

  At this time, if the main body orientation display 16 is present, the orientation indicated by the nut orientation indication 36 of the flare nut 30 and the orientation indicated by the main body orientation indication 16 of the joint body 10 are further matched. The sub through hole 34 can be easily adjusted to a desired position. However, even if the main body orientation display 16 is not necessarily provided, it is possible to obtain a certain effect as described above.

  Further, the configuration in which the nut orientation display 36 and the main body orientation display 16 in the third embodiment are provided can be used together with the configuration in which the sub through-hole position display 35 in the second embodiment is provided.

Embodiment 4 FIG.
FIG. 10 relates to Embodiment 4 of the present invention, and is a cross-sectional view, a front view, and a top view showing the overall configuration of the pipe connection structure.
As shown in FIG. 10, in the fourth embodiment described here, a body side fastening position display 17 is provided on the outer surface of the joint body 10, and a nut side fastening position display 37 is provided on the outer surface of the flare nut 30. Is provided. Here, the main body side fastening position display 17 is an arrow type facing the side to which the flare nut 30 is attached. Moreover, the nut side fastening position display 37 is an E-shaped mark with the side opened to the joint body 10 side facing.

  The nut side fastening position display 37 is arranged at a position facing the body side fastening position display 17 in a state where the flare nut 30 is fastened to the joint body 10. That is, in a state where the flare nut 30 is fastened to the joint main body 10, the E-shaped central horizontal line of the nut side fastening position display 37 is just aligned with the tip of the arrow of the main body side fastening position display 17.

Here, “the state in which the flare nut 30 is fastened to the joint body 10” means that the female thread portion 31 of the flare nut 30 is sufficiently fastened to the male screw portion 14 of the joint body 10 and the nut inner surface portion 33 is the flare outer surface. By pressing the portion 23, the flare inner surface portion 22 is in airtight contact with the tip surface portion 15, and the flare outer surface portion 23 airtightly closes the opening of the nut inner surface portion 33 of the sub through hole 34. .
Other configurations are the same as those in the first embodiment, and detailed description thereof is omitted.

  According to the configuration of the fourth embodiment, when the flare nut 30 is fastened to the joint body 10, the operator always confirms the main body side fastening position display 17 and the nut side fastening position display 37 so that the constant is always constant. It can be set as a fastening state. Therefore, it is possible to maintain the airtight state in the joint portion appropriately.

  Furthermore, the constant fastening state always means that the sub through hole 34 of the flare nut 30 is always in the same relative position with respect to the joint body 10. Therefore, for example, when the refrigerant pipe is passed in the horizontal direction, the sub through-hole 34 is reliably located above the gravity direction when viewed from the center axis of the flare nut 30 with the flare nut 30 fastened to the joint body 10. Can be arranged.

  That is, when the joint portion is loosened due to unforeseen circumstances and the refrigerant in the pipe leaks from the joint portion, the leaked refrigerant is less likely to stay or is more easily diffused. Thus, it is possible to surely take a measure of adjusting the positional relationship between the 20 and the flare nut 30 as described above, and to improve the workability at that time.

  In addition, the structure which provides the main body side fastening position display 17 and the nut side fastening position display 37 of the fourth embodiment is combined with the structure of the nut orientation display 36 (and the main body orientation display 16) of the third embodiment described above. Can also be used.

  Further, by arranging the main body side fastening position display 17 and the nut side fastening position display 37 corresponding to the position where the sub through hole 34 is formed, the function of the sub through hole position display 35 of the second embodiment can be achieved. In particular, the nut side fastening position display can be provided.

  DESCRIPTION OF SYMBOLS 10 Joint main body, 11 Base part, 12 Joint part, 13 Main body through-hole, 14 Male thread part, 15 End surface part, 16 Main body direction display, 17 Main body side fastening position display, 20 Flare pipe, 21 Flare part, 22 Flare inner surface part, 23 Flare outer surface part, 30 Flare nut, 31 Female thread part, 32 Main through hole, 33 Nut inner surface part, 34 Sub through hole position display, 35 Sub through hole position display, 36 Nut orientation display, 37 Nut side fastening position display

Claims (5)

A pipe connection structure for connecting refrigerant pipes filled with refrigerant having an average molecular weight larger than air,
One end of the refrigerant pipe is connected to one end, a male thread portion is formed on the other end, and a joint body in which a tapered distal end surface portion is formed at the distal end of the male thread portion;
The other end of the refrigerant pipe is connected to one end, a flare-like flare portion is formed at the other end, and a flare pipe that allows the flare inner surface portion of the flare portion to be in close contact with the tip surface portion;
A female screw part corresponding to the male screw part, a main through hole through which the flare pipe passes, and an inner surface part of the nut that can come into contact with a flare outer surface part of the flare part of the flare pipe passed through the main through hole. A formed flare nut, and
In the flare nut, a sub through hole penetrating the nut inner surface portion and the outer side of the flare nut is formed separately from the main through hole,
The inner diameter of the main through hole is adjusted according to the outer diameter of the flare pipe,
In a state where the flare nut is fastened to the joint body, the inner surface of the nut presses the outer surface of the flare so that the inner surface of the flare is in close contact with the tip surface, and the outer surface of the flare is A pipe connection structure that hermetically closes the opening of the nut inner surface portion of the sub through hole.   Provided on the outer surface of the flare nut so that the sub through hole is disposed on the upper side in the gravity direction when viewed from the center axis of the flare nut in a state where the flare nut is fastened to the joint body. The pipe connection structure according to claim 1, further comprising a direction indication indicating a direction of the flare nut.   The pipe connection structure according to claim 1 or 2, further comprising a position display provided on an outer surface of the flare nut and indicating a position where the sub through hole is formed. Main body side fastening position indication provided on the outer surface of the joint body;
A nut-side fastening position display provided on an outer surface of the flare nut and disposed at a position opposite to the body-side fastening position display in a state where the flare nut is fastened to the joint body. The pipe connection structure according to claim 1 or 2.   The pipe connection structure according to claim 4, wherein the main body side fastening position display and the nut side fastening position display are arranged corresponding to the position where the sub through hole is formed.

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