JP5723470B1 - Pipe joint structure for refrigerant - Google Patents

Abstract

Provided is a refrigerant joint structure capable of quickly and strongly connecting without flaring an end portion when a pipe is made of a copper pipe. In a refrigerant pipe joint structure for connecting a copper pipe, a joint body 1 with a male thread and a cap nut 3 screwed onto a male thread 2 of the joint body 1 are provided. It is stored in the internal storage space 10 and has a concave circumferential groove 9 on the outer peripheral surface 8. When the cap nut 3 and the male screw 2 of the joint main body 1 are screwed together, the joint main body 1 and the cap nut 3 extend in the axial direction. In response to the compressive force, the concave circumferential groove bottom thin wall portion 13 is plastically deformed radially inward, and has a metal retaining ring body Z that bites from the outer peripheral surface side of the inserted copper tube and retains it. In addition, the inner storage space 10 of the cap nut 3 has an intermediate interposer 6 having an axial concavo-convex ridge 52, and is prevented from rotating. [Selection] Figure 1

Description

  The present invention relates to a pipe joint structure for refrigerant.

As one type of pipe joint, a flare joint has been used for a long time (for example, see Patent Document 1).
Generally, as shown in FIG. 13, the end portion of the copper pipe 35 is between the tapered surface 31 of the male threaded joint body 30 and the tapered surface 34 of the cap nut 33 that is screwed onto the male thread 32 of the joint body 30. The flare end portion 37 formed by plastic working is expanded and tapered so as to be sandwiched and sealed with a pressing force.
However, since it was necessary to perform flare processing in the field, the improvement of piping work efficiency was hindered.

Therefore, the present inventor has solved the above-mentioned drawbacks of the conventional flare joint (as shown in FIG. 13), and further has a small number of parts and a simple part-shaped pipe joint structure as shown in FIG. Proposed an invention (see Patent Document 2).
That is, in FIG. 14, a compression deformation sleeve 40 is provided in the internal storage space 39 of the cap nut 38, and the cap nut 38 is screwed into the male screw 42 of the joint body 41, and this screwing is performed. By applying a strong compressive force in the axial direction by the tapered distal end surface 43 of the joint body 41 and the inner flange 38A of the cap nut 38, the axial width of the two outer circumferential grooves 44, 44 of the sleeve 40 is given. While reducing the size, the groove bottom thin wall portion 45 of the outer circumferential groove 44 is plastically deformed radially inward, and the plastically deformed groove bottom thin wall portion 45 is bitten into the outer peripheral surface of the inserted pipe 46. Thus, the pipe 46 is prevented from being pulled out (as shown in FIG. 14). Reference numeral 47 denotes a seal layer coated with PTFE or the like, which is strongly compressed to increase the sealing action (seal performance) as the groove bottom thin wall portion 45 bites into the outer peripheral surface of the pipe 46. .

Japanese Patent Laid-Open No. 2005-42858 Japanese Patent No. 5276215

  The refrigerant pipe joint shown in FIG. 14 is an excellent invention that can replace the flare joint (shown in FIG. 13), but the present inventor has noticed that the following points to be improved remain. . That is, (i) the pull-out force of the pipe 46 is considered to be sufficient for the refrigerant piping, but there is a little anxiety regarding the sealing performance of the refrigerant gas (under the usage conditions as shown in FIG. 12 described later). At some point, (ii) the covering operation of the seal layer 47 shown in FIG. 14 is troublesome and costly, and the seal is partially sealed with the plastic deformation of the groove bottom thin wall portion 45 as shown in FIG. There is a possibility that the layer 47 breaks, and the sealing performance is lowered.

  The present invention includes a joint body with a male thread having a tapered surface with a reduced diameter at the tip and a cap nut, and is housed in the inner housing space of the cap nut, and the cap nut is screwed into the male thread of the joint body. A metal retaining ring body that bites into the outer peripheral surface of the metal tube and prevents it from being removed while forming a closed annular reduced diameter deformed portion in the inserted metal tube, and the retaining ring body is An elastic seal member is omitted by preventing fluid external leakage at the closed annular bite portion that bites into the outer peripheral surface of the metal tube; a flare portion that presses against the tapered surface at the tip of the joint body, and a metal tube end portion A thin metal intermediate interposer integrally having a straight cylinder portion to be inserted is accommodated in the internal storage space; an axial concavo-convex ridge portion in which the reduced diameter deformed portion bites into and stops the pipe rotation, Stroke of the above intermediate body A structure formed on the outer peripheral surface of the over preparative tubular portion.

  According to the present invention, even when a rotational torque acts on the pipe (metal pipe), the diameter-reduced deformation portion can bite into the axial concavo-convex ridge portion to prevent the pipe from rotating. The outer peripheral surface of the metal pipe (pipe) and the closed annular bite that has penetrated the metal pipe (in the state without the elastic seal member) prevent fluid external leakage, but this part is around the shaft center. If the relative rotation occurs even slightly, fluid external leakage may occur. Since this relative rotation can be reliably prevented by the biting of the reduced diameter deforming portion and the axial concavo-convex portion, the fluid external leakage can be prevented.

Further, the sealing layer is not required to be coated, and an elastic seal member such as an O-ring is omitted, achieving cost reduction and excellent durability.
Furthermore, the intermediate body consisting of a flare part and a straight tube part can be manufactured easily and inexpensively by metal plastic processing such as deep drawing from a thin metal plate or flare processing to a metal pipe. is there. Further, the flare portion of the intermediate body is brought into pressure contact with the reduced diameter tapered surface of the joint body, and the sealing function of the flare joint (which has been widely used for a long time) is utilized to exhibit stable sealing performance.
In particular, when the outdoor unit of an air conditioner falls, the pipe twists about 90 °, and rotational torque acts on the pipe. In the present invention, the straight cylindrical portion of the intermediate interposer and the pipe (metal pipe) Rotation of the pipe (metal pipe) is prevented by the strong rotation between the pipe and the outer peripheral surface of the pipe and the closed ring-shaped diameter-reduced deformation part does not occur, and the sealing performance (sealability) Can be stably maintained over a long period of time.

It is sectional drawing of the cap nut untightened state which shows one Embodiment of this invention. It is sectional drawing of a cap nut fastening completion state. It is a cross-sectional view of the main part. It is a figure explaining an example of the manufacturing method of an intermediate body. It is a figure explaining the other example of the manufacturing method of an intermediate body. It is principal part sectional drawing of the cap nut untightened state which shows other embodiment of this invention. It is principal part sectional drawing of the completion state of a cap nut fastening which shows other embodiment. It is a figure which shows the specific example of an intermediate body, Comprising: (A) is a semi-cylindrical side view, (B) is a side view. It is principal part expansion explanatory drawing of FIG. It is principal part sectional drawing of the cap nut untightened state which shows another embodiment of this invention. FIG. 3 is an enlarged explanatory view showing only a main part of a compression deformation sleeve in a compressed state. It is a perspective view explaining the test method which provides rotational torque to a pipe. It is sectional drawing which shows a prior art example. It is sectional drawing of the pipe connection completion state which showed the other conventional example.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
1 and 2 show an embodiment of the present invention. FIG. 1 is a sectional view showing an untightened state, and FIG. 2 is a sectional view showing a tightening (connection) completed state.

The present invention is a pipe joint structure for refrigerant, and includes a joint body 1 with a male screw 2 and a cap nut 3, and an internal storage space 10 of the cap nut 3 has a metal retaining ring body Z. 1 and 2 show a case where the retaining ring body Z is a compression deformation sleeve 7.
The compression deformation sleeve 7 has a plurality of U-shaped concave grooves 9 and 9 (two are shown in FIGS. 1 and 2) on the outer peripheral surface 8, and the cap nut 3 is connected to the male joint body 1. When the screw 2 is screwed, it receives a compressive force F in the axial direction, and the concave circumferential groove bottom thin wall portion 13 is plastically deformed radially inwardly. The metal pipe P is prevented from being pulled out by forming a closed annular reduced diameter deforming portion 12 in the P).

  Further, the joint body 1 has a tip diameter-reduced tapered surface 48. In particular, it is also desirable that the joint body 30 (for connecting a flare pipe) that has been used for many years as shown in FIG. 13 is used (shared) as it is for the joint body 1 of the present invention.

  As shown in FIG. 2, fluid (refrigerant) external leakage is prevented by a closed annular biting portion 16 in which the retaining ring body Z bites into the outer peripheral surface 15 of the metal tube. That is, an elastic seal member such as a rubber O-ring or U-packing is omitted between the inner peripheral surface of the retaining ring body Z (compression deformation sleeve 7) and the outer peripheral surface 15 of the metal pipe P. .

In FIG. 1 to FIG. 5, reference numeral 6 denotes a thin metal intermediate body, and this intermediate body 6 is a (morning glory type) flare portion that is in pressure contact with the reduced diameter tapered surface 48 of the joint body 1. 6A and the straight cylinder part 6B inserted in the metal pipe end part 5 are integrally provided. It can be said that the intermediate body 6 is stored in the internal storage space 10 of the cap nut 3. And the axial direction uneven | corrugated strip 52 is formed in the outer peripheral surface of the straight cylinder part 6B of this intermediate body 6. As shown in FIG. As shown in FIGS. 3 (A) and 3 (B), the ridges of the concavo-convex ridge portion 52 project in parallel (in a direction parallel to the axis L ₀ ) as a transverse cross section or a triangle, As shown in FIG. (In addition, it is good also as the uneven | corrugated strip 52 of shapes other than this.)

  As shown in FIG. 2, when the cap nut 3 is screwed into the male screw 2 of the joint body 1, the metal retaining ring body Z (compression deformation rib 7) locally exerts a large external force in the radial inward direction. The reduced diameter deformed portion 12 is applied to the metal pipe P and bites into the axial concavo-convex ridge portion 52 of the straight tube portion 6B to prevent the pipe from rotating.

Next, in FIG. 4, an example of the manufacturing method of the above-mentioned intermediate body 6 is shown. A deep cup having the bottom wall portion 25 shown in FIG. 4 (B) by the deep drawing processing of the thin metal plate piece 24 as shown in FIG. 4 (A) and the upper enlarged flare portion 6A at the upper opening end. Plastic working into a shape. At this time, it is also desirable to plastically process the axial concavo-convex ridge 52 at the same time. Next, as shown in FIG. 4C, the intermediate interposer 6 can be manufactured by punching the bottom wall portion 25 with a press or the like.
The axial concavo-convex ridges 52 may be formed by plastic processing (such as knurling), which is different from the deep drawing processing, or may be performed by machining.

FIG. 5 shows another example of the method for producing the intermediate interposer 6. A thin metal short tube 26 as shown in FIG. 5 (A) is obtained by cutting a pipe, and one open end of the short tube 26 is plastically processed in the direction of arrow C. A flare portion 6A is formed, and an axial concavo-convex portion 52 is formed on the straight tube portion 6B by machining or the like.
The intermediate interposer 6 can be manufactured inexpensively and easily by such a simple manufacturing method. Incidentally, the outermost end edge of the flared portion 6A of the intermediate medium members 6, planar Tansototsuba portion 6C which is perpendicular to the axis L ₀ is formed.

  If the compression deformation sleeve 7 is further described, the hole portion has a stepped portion 27 in the vicinity of the inner end, and the metal pipe P is inserted up to the stepped portion 27. The vicinity of the inner end of the compression deformation sleeve 7 is thick. That is, a thick head 62 having a sloped surface 61 that presses against (presses) the flare portion 6A of the intermediate interposer 6 is provided near the inner end. A cover member 29 is interposed between the inner peripheral surface of the cap nut 3 and the outer peripheral surface of the sleeve 7 to reduce the rotational torque of the cap nut 3. Further, as shown in FIG. 2, the smooth circumferential surface portion 63 of the inner peripheral surface of the cap nut 3 is an outer peripheral surface in the vicinity of the inner end of the compression deformation sleeve 7 in a pipe connection state after the cap nut 3 is screwed. In pressure contact with 64, excessive deformation of the inner end of the sleeve 7 in the radially outward direction is prevented.

By the way, as a pipe joint structure for refrigerants of the present invention, the metal pipe P uses an aluminum pipe or a copper pipe. 1 and 2 show the case where the O-ring 65 is used only at the foremost end of the cap nut 3, but otherwise no elastic seal material is used, and the metal is strongly pressed (adhered). It has a sealing action.
As the cap nut 3 is screwed, the compression deformation sleeve 7 receives the axial compression force F as shown in FIG. 2, and the concave circumferential groove bottom thin wall portion 13 is plastically deformed radially inward. Then, it bites in from the outer peripheral surface 15 of the inserted pipe P to prevent it from coming off, and exhibits a pull-out resistance. The width dimension of the concave circumferential groove 9 decreases as shown in FIGS. 1 to 2 and becomes a narrow U-shape or a narrow V-shape. Further, the reduced diameter deformed portion 12 of the pipe P bites into the concave portion of the axial concavo-convex portion 52 (as shown in FIG. 2), and the relative rotation (about the axis L ₀ ) relative to the intermediate interposer 6. Can be powerfully blocked. At this time, the flare portion 6A of the intermediate interposed body 6 is strongly pinched by the tapered surface 48 and the inclined surface 61, and the intermediate interposed body 6 does not rotate. Accordingly, the rotation of the pipe P around the axis L ₀ is strongly prevented.

  As shown in FIG. 2, according to the plastic deformation of the groove bottom thin wall portion 13 of the concave circumferential groove 9, the anti-rotation function of the pipe P is strong, and the pull-out force of the pipe P is strong, The sealing performance and sealing performance (without a sealing material) are sufficiently exerted against the refrigerant.

FIG. 11 is an enlarged explanatory view of the main part of the compression deformation sleeve 7 when the metal pipe P is removed under the compression connection completed state shown in FIG. 2. As is apparent from FIG. A large number of ridges N are generated on the inner peripheral surface of each groove bottom thin wall portion 13 in the circumferential groove 9 when plastically deforming into a U shape or a V shape. The reason is estimated to be that 皺 N is generated along with the compression deformation because the entire diameter is reduced.
Naturally, in the (corresponding) pressure contact portion on the pipe P side, wrinkles having a concave portion and a convex portion are generated, and the concave and convex portions are densely inserted into each other. However, the mutual rotation blocking force (grip function) between the metal tube P and the sleeve 7 is weak because copper and aluminum are soft metals.

Assuming the case where there is no anti-rotation function (grip function) in which the rotation of the metal pipe P is prevented by the axial concavo-convex portion 52 of the intermediate interposer 6, the concave circumferential groove 9 is made of copper or aluminum. Even though the metal tube P and the sleeve 7 are uneven by the ridge N (as shown in FIG. 11), the metal tube easily rotates (that is, the ridge N is small and the material is Because it is soft).
With such rotation, concavity and convexity conversely generates a very small gap, and the refrigerant leaks to the outside. As a result of the experiment, it has been found that the refrigerant (gas) leaks to the outside when the metal tube P is rotated by a minute angle of 1 ° to 2 ° from the state in which the unevenness caused by the minute ridges N enters.
In the present invention, since the metal tube P can be strongly prevented from rotating with respect to the joint body 1, it can be sealed against a gas such as a refrigerant for a sufficiently long period of time and under severe use conditions. Exhibits performance (sealability) and prevents external leakage.

  The pipe joint structure according to the present invention is used on a side surface of a box-type air conditioner outdoor unit, and is used to connect a refrigerant pipe. As shown in FIG. 12, the joint body 1 is attached to the side surface of the outdoor unit 17, and the cap nut 3 is screwed to the joint body 1 (see FIG. 2). If the outdoor unit 17 rolls over due to an earthquake or the like when it is bent in an L shape in the vicinity, the metal pipe P is twisted in the direction of arrow M. If the twist angle is β, β = 90 ° in a normal rollover accident.

Further, as shown in the perspective explanatory view shown in FIG. 12, the pipe joint X is compared using the conventional joint shown in FIG. 14 and the pipe joint of the embodiment of the present invention (FIGS. 1 and 2). An experiment (refrigerant external leakage experiment) was conducted. Specifically, it is fixed to the air conditioner outdoor unit 17 (a fixed wall surface corresponding thereto) in a horizontally projecting manner, and the metal pipe P is bent vertically upward at the minimum possible bend radius R ₁ . Gripping with a gripping tool at the boundary of the radius R ₁ and the straight boundary (indicated by two triangles 21 and 21), torsion is applied to the metal tube in the direction of arrow M, and the coolant An external leakage test was conducted by flowing the pipe joint X and the metal pipe P while applying the maximum working pressure in a normal use state. As the metal pipe P, a copper pipe P _Cu and an aluminum pipe P _Al were used.

The experimental results were as shown in Table 1 below.

As can be seen from Table 1 above, in the conventional pipe joint, there is a high possibility of external leakage of the refrigerant when the outdoor unit 17 falls down. When the metal tube is twisted in this way, there is anxiety about the sealing performance. On the other hand, in the embodiment of the present invention, in both the copper pipe P _Cu and the aluminum pipe P _Al , the metal pipe twist angle β sufficiently exceeding about 90 ° even if the outdoor unit 17 falls down. It has been found that there is no concern about refrigerant leakage until stable and excellent sealing performance is exhibited.

In addition, returning to FIG. 1 and FIG. The joint body 1 has a tapered surface 48 at the tip, and the flared portion 6A of the intermediate interposer 6 has a pressure contact sealing tapered inner surface 53 having the same taper angle. The taper surfaces 48 and 53 are sealed by pressure contact in the same manner as the JIS B8607 flare joint. Further, the sealing by the press-contact between the inner end inclined surface 61 of the retaining ring body Z and the flare portion 6A is also satisfactorily sealed.
1 and 2, a cover member 29 of hard metal (or hard plastic) such as stainless steel is attached to the compression deformation sleeve 7 in an outer fitting shape. The cover member 29 is a cylindrical member that reduces frictional resistance (resistance due to pressure bonding) between the inner peripheral surface of the cap nut 3 and the outer peripheral surface of the compression deformation sleeve 7 and promotes slipping.

The small bottom wall 13 that is plastically deformed into a U-shape (or V-shape) by the small ridge N generated by the deformation in the diameter reducing direction as shown in FIG. Even though they are engaged with each other, they are in a pressure contact state between soft materials such as copper and copper, or aluminum and aluminum, and in the direction of arrow M as described in FIG. If the torsional force of the metal tube acts, a slight rotational slip of 1 ° to 2 ° is generated, and the small ridge N forms a very small flow path through which gas (refrigerant) passes. However, it is considered that external leakage occurs, and the present invention can prevent such external leakage easily and stably by the axial concavo-convex ridge portion 52.
In the present invention, the parts are combined with materials that do not cause an electric corrosion phenomenon. The O-ring 65 of FIG. 1 can be omitted, and in this case, it can be said that the present invention does not use a material that causes deterioration (corrosion) due to a refrigerant such as rubber or plastic. It is a further feature that welding and silver soldering work are not required at all.

6 to 9 show another embodiment of the present invention. FIG. 6 is a cross-sectional view showing an untightened state, and FIG. 2 is a sectional view showing a tightened (connected) completed state, and shows only a half above the axis L ₀ . The same reference numerals as those in the above-described embodiment shown in FIGS. The point that the embodiment of FIGS. 6 to 9 is different from that of FIGS. 1 to 5 will be mainly described below.

The shape of the metal retaining ring body Z housed in the inner housing space 10 of the cap nut 3 does not have the concave circumferential grooves 9 and 9 shown in FIGS. The diameter of the pipe P is reduced, and the pipe P is bitten from the outer peripheral surface 15 to prevent the pipe P from being removed. Therefore, on the inner peripheral surface of the cap nut 3, a gradually reduced diameter gradient surface 66 is continuously formed from the outer end of the smooth circumferential surface portion 63, and a short axial is formed on the outer end of the gradient surface 66. A short circumferential surface portion 67 that is parallel to the axis L ₀ and extends in the direction dimension is provided continuously, and a steep slope portion 68 is formed on the outer end of the short circumferential surface portion 67 so as to have an outwardly reduced diameter. Yes.
The shape of the inner end of the retaining ring body Z is the same as that shown in FIGS. 1 and 2, has a thick head 62, and has a stepped portion 27.
The tip end portion 18 of the retaining ring body Z is connected to the outer end of the neck portion 19 which is slightly thinned, and has a rounded and sloped surface from the outer periphery to the tip surface as a small head shape. It has a small convex portion 20 that bites into the surface.

As the cap nut 3 is screwed, the distal end portion 18 of the retaining ring body Z is deformed inward in the radial direction while being in sliding contact with the reduced diameter gradient surface 66 of the inner surface of the cap nut 3, and gradually the outer peripheral surface of the pipe P. 7 and finally, as shown in FIG. 7, when the sloped surface 22 of the tip 18 is pressed by the steeply sloped portion 68, it is strongly pressed by the short circumferential surface portion 67 in the radial inward direction. Thus, the small convex part 20 bites into the pipe P, and the closed annular biting part 16 is formed. That is, as shown in FIG. 6, the closed annular biting portion 16 is formed by the radially inward deformation of the small convex portion 20 that originally existed, thereby preventing fluid external leakage.
At this time, the pipe P is formed with a closed annular reduced diameter deformed portion 12, and the closed annular reduced diameter deformed portion 12 bites into the axial concavo-convex ridge 52 of the intermediate body 6 to prevent the pipe from rotating. Do.

By the way, as shown in FIG. 6 and FIG. 9 and the like, the relative rotation between the retaining ring body Z and the intermediate interposing body 6 is performed. It is blocked by biting into the inner peripheral surface 62A of the thick head 62. That is, when the intermediate interposing body 6 and the retaining ring body Z are relatively pushed in the axial direction and assembled, the axial concavo-convex portion 52 bites into the inner peripheral surface 62A, and the retaining ring body Z The intermediate ring 6 is prevented from rotating relative to each other, and when the cap nut 3 is screwed, the retaining ring body Z does not rotate around the axis L ₀ , and the small convex portion 20 (shown in FIG. 7). It is possible to prevent rotational slippage on the outer peripheral surface 15 of the pipe P (after completion of connection), and to more reliably prevent fluid leakage from this portion.
In FIG. 7 (similar to FIG. 2), the retaining ring body Z bites into the outer peripheral surface 15 of the pipe P at the closed annular biting portion 16 (small convex portion 20). Prevents external leakage. That is, an elastic seal member such as a rubber O-ring or U packing is omitted between the inner peripheral surface of the retaining ring body Z and the outer peripheral surface 15 of the pipe P.

  As shown in FIG. 8, the thin metal intermediate interposer 6 has substantially the same shape as that in FIGS. 1, 2, etc., but a stepped portion 6 E is provided at the boundary portion between the flare portion 6 A and the straight tube portion 6 B. The inner peripheral surface 62A of the thick head 62 shown in FIG. 9 is fitted with high accuracy and is configured to accurately abut on the stepped portion 6E under the pressed state of FIG. Is done. Furthermore, the number of ridges of the concavo-convex ridge portion 52 in the axial direction in FIG. 8 is set to be smaller than that in FIG. 3, and is formed sufficiently long in the axial direction. The manufacturing method of this intermediate | middle interposition body 6 is as having already demonstrated in FIG. 4, FIG.

Next, FIG. 10 shows another embodiment, in which the retaining ring body Z is divided into a base end side first member Z ₁ and a tip end side second member Z ₂ , and the first member Z ₁ is shown in FIG. 7 corresponds to the thick head 62 and (slightly thick neck 19) of the retaining ring body Z of FIG. 7, and has a tapered surface 49 that expands in the distal direction, while the second member Z ₂ is It has an inner end side tapered surface 69 that expands in the distal direction and an outer end side tapered surface 70 that decreases in the distal direction, and has small convex portions 20A and 20B at the inner and outer ends, respectively.
As the cap nut 3 is screwed, the second member Z ₂ receives a compressive force F, and the small and convex portions 20A and 20B at the inner and outer ends serve as closed annular bites 16 and 16, respectively. 1 and FIG. 7, the reduced diameter deformed portion 12 (see FIGS. 2 and 7) bites into the axial concavo-convex portion 52 of the intermediate interposer 6, and the pipe A detent is made.

By the way, in the present invention, when the reduced diameter deformed portion 12 bites into the axial direction uneven strip portion 52, only the convex strip portion of the axial direction uneven strip portion 52 or only the concave strip portion bites. Or the state in which the concave and convex ridges bite may be used.
Also, in FIGS. 6 to 10, the axial concavo-convex portion 52 of the intermediate interposer 6 is set so as to bite lightly when the pipe is inserted so that it can be inserted by a human hand. After setting the dimensional tolerance and inserting the pipe, until the cap nut 3 is screwed up (until the disclosure of construction), the pipe will come off a little, and it will be constructed under insufficient pipe insertion conditions. There is an advantage that can be effectively prevented. Of course, in the embodiment described with reference to FIGS. 1 and 2, it is preferable that the dimension in the axial direction of the concavo-convex portion 52 is sufficiently long as a similar dimensional tolerance.

  The shape of the retaining ring body Z can be freely deformed other than illustrated, and can also be configured with a disc spring. For example, two disc springs are arranged symmetrically in the internal storage space 10 of the cap nut 3, and the inner end edge of the disc spring is bitten into the pipe outer peripheral surface 15 by the screwing of the cap nut 3. (Not shown).

In the present invention, the closed annular reduced-diameter deformed portion 12 is caused to bite into the axial concavo-convex ridge portion 52 of the intermediate interposer 6 to prevent the pipe from rotating, thereby preventing a seal (seal) breakage from occurring. This is a major feature. In addition, the flare portion 6A of the intermediate interposer 6 is held between the tapered surface 48 and the inclined surface 61, and the rotation is reliably prevented.
Further, as shown in FIGS. 6 and 9, the intermediate body 6 and the retaining ring body Z are structured so as not to rotate easily by the biting of the axial concavo-convex ridge 52, and the cap nut 3 is screwed. It is also desirable to prevent the retaining ring body Z from rotating from the initial stage of advancement. Accordingly, in the embodiment shown in FIGS. 1 and 2, similarly, the structure of preventing the rotation of the retaining ring body Z from the initial stage of screwing of the cap nut 3 (shown in FIG. 9) is adopted. You can also.

  As described in detail above, the present invention includes the joint body 1 with the male thread 2 having the tapered diameter tapered surface 48 and the cap nut 3, and is housed in the internal storage space 10 of the cap nut 3, and When the cap nut 3 is screwed into the male screw 2 of the joint body 1, the metal pipe P is inserted into the outer peripheral surface 15 of the metal pipe P while forming the closed annular reduced diameter deforming portion 12 and is prevented from being pulled out. A metal retaining ring body Z is provided. Further, the retaining ring body Z prevents leakage of fluid outside at the closed annular biting portion 16 in which the metal pipe outer circumferential surface 15 bites, thereby omitting an elastic seal member. A thin metal intermediate interposer 6 integrally having a flare portion 6A in pressure contact with the tip diameter-reduced tapered surface 48 of the joint body 1 and a straight tube portion 6B inserted into the metal tube end portion 5; , Stored in the internal storage space 10; Since the axial concavo-convex ridge portion 52 for preventing the rotation of the ip is formed on the outer peripheral surface of the straight cylindrical portion 6B of the intermediate interposer 6, the torsional force M (see FIG. 12) acts on the metal pipe P. In particular, reliable pipe rotation prevention is performed, and (a trace amount) of refrigerant leakage due to relative rotation between the metal pipe P and the closed annular biting portion 16 is prevented, and the sealing performance is stable and excellent. .

Further, the flare joint that has been widely used for a long time as the joint body 1 can be used as it is, and is suitable for repairing the conventional pipe joint illustrated in FIG. Further, the intermediate interposer 6 can be manufactured inexpensively and efficiently by deep drawing of a thin metal plate material or flare processing of a short metal tube (see FIGS. 4 and 5).
Moreover, even if the rubber seal member is omitted, reliable sealing performance can be obtained, and it can be said that the pipe joint is particularly suitable for a highly corrosive refrigerant.

DESCRIPTION OF SYMBOLS 1 Joint body 2 Male screw 3 Cap nut 6 Intermediary body 6A Flare part 6B Straight cylinder part
10 Internal storage space
12 Closed annular reduced diameter deformed part
15 Metal pipe outer peripheral surface
16 Closed ring bite
48 Tip diameter tapered surface
52 Axial concavo-convex strip P Metal pipe
Z retaining ring body

Claims (1)

A joint body (1) with a male thread (2) having a tapered diameter tapered surface (48) and a cap nut (3) are housed in the internal storage space (10) of the cap nut (3), and When the cap nut (3) is screwed into the male screw (2) of the joint body (1), a closed annular reduced diameter deforming portion (12) is formed in the inserted metal pipe (P). A metal retaining ring body (Z) that bites into and prevents the metal pipe outer peripheral surface (15) from being removed, and further, the closed ring body (Z) that bites into the metal pipe outer peripheral surface (15). The annular bite (16) prevents fluid external leakage and eliminates the elastic seal member.
A thin-walled body integrally having a flare portion (6A) pressed against the tip diameter-reduced tapered surface (48) of the joint body (1) and a straight tube portion (6B) inserted into the metal tube end portion (5). A metal intermediate body (6) is stored in the internal storage space (10),
An axial concavo-convex ridge (52) that bites into the reduced diameter deformed portion (12) and stops the pipe is formed on the outer peripheral surface of the straight cylindrical portion (6B) of the intermediate interposer (6). A refrigerant pipe joint structure.

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