JP2015135170A - Pipe joint structure for refrigerant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint structure for refrigerant in the case that a pipe is formed of a copper tube, no flare work is set at an end part and a strong connection can be attained rapidly.SOLUTION: The present invention relates to a refrigerant pipe joint structure for connecting a copper pipe Pcomprising a male-threaded joint main body 1 and a cap nut 3 engaged in thread with a male thread 2 of the joint main body 1 in which it has a compression deforming sleeve 7 stored in an inner storing space 10 of the cap nut 3, having a concave peripheral groove 9 at an outer circumferential surface, receiving a compression force F in an axial direction from the joint main body 1 and the cap nut 3 when the cap nut 3 and the male thread 2 of the joint main body 1 are engaged to each other in thread, a thin wall part 13 of the concave peripheral groove shows a plastic deformation in a radial inner direction, bites from the outer circumferential surface 14 of the copper pipe Pto perform anti-loosening and there is provided a stainless steel rotation stopping cylindrical body 50 in correspondence with the second concave circumferential groove 92 at an outer end side. Further, after the first concave circumferential groove 91 shows a plastic deformation, the second concave circumferential groove 92 shows a plastic deformation.

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).
In general, as shown in FIG. 19, 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 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. 19), 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. 20, when 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 onto the male screw 42 of the joint body 41, By applying a strong compressive force in the axial direction by the tapered distal end surface 43 of the joint body 1 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. Therefore, the pipe 46 is prevented from being pulled out (as shown in FIG. 20). Reference numeral 47 denotes a seal layer coated with PTFE or the like, which is strongly compressed to increase the sealing action 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

  Although the refrigerant pipe joint shown in FIG. 20 is an excellent invention that can replace the flare joint (shown in FIG. 19), 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 concern about the sealing performance of the refrigerant gas (under the usage conditions as shown in FIG. 11 described later). At a certain point, (ii) the covering operation of the sealing layer 47 shown in FIG. 20 is troublesome and expensive, and the sealing is partially performed with the plastic deformation of the groove bottom thin wall portion 45 as shown in FIG. (Iii) FIG. 20 shows the compression state of the compression deformation sleeve 40, but compression is performed by screwing the cap nut 38 from the uncompressed state. In the middle of the deformation, in order to simultaneously plastically deform the two outer circumferential grooves 44, 44, in addition to the deformation of the groove bottom thin wall portion 45 in the radial inward direction (especially the outer circumferential concave on the axial outer side). Along the axial direction (in the groove 44), a large recess is formed on the outer peripheral surface of the pipe 46. It is was found. That is, by forming such a large recess in the outer peripheral surface of the pipe 46, the refrigerant sealing performance is reduced, external leakage occurs, and further, along with the rotation of the pipe 46 around the axis, Increased external leakage. (This point (iii) to be improved will be described later with reference to FIGS. 16 to 18).

  The present invention comprises a joint body with a male thread and a cap nut screwed onto the male thread of the joint body, and is housed in the internal housing space of the cap nut and has a concave circumferential groove on the outer peripheral surface. When the cap nut and the male screw of the joint body are screwed together, an axial compression force is received from the joint body and the cap nut, and the concave circumferential groove bottom thin wall portion is plastically deformed radially inward. In the refrigerant pipe joint structure having a compression deformation sleeve that bites in from the outer peripheral surface side of the inserted metal pipe and prevents it from being removed, the concave circumferential groove is a first concave circumferential groove on the axial inward side. And a second concave circumferential groove on the axial outer direction side, and the sequential concave cover member that causes the plastic deformation in order with the first concave circumferential groove first and the second concave circumferential groove behind. Is externally fitted to the compression deformation sleeve.

  The sleeve for compression deformation is formed with a tapered surface that is reduced in diameter in an axially outward direction at an intermediate outer peripheral surface portion between the first concave groove and the second concave groove, and the sequential control cover member. Includes an inner flange portion at an end portion in the axial outer direction, and a tapered surface that is fitted in correspondence with the tapered surface of the compression deformation sleeve in an uncompressed state.

Further, the innermost edge is made of stainless steel, which is inserted in advance from the outer end side in the axial direction of the compression deformation sleeve and reaches the depth corresponding to the thin groove bottom wall of the second concave groove. The cylindrical body has a C-shaped non-rotating cylindrical body having a notch, and has a pipe biting recess and / or a protrusion on the innermost edge and the outermost edge in the axial direction.
The sequential control cover member also has a function of promoting relative rotational slip between the inner peripheral surface of the cap nut and the outer peripheral surface of the compression deformation sleeve.

According to the present invention, the groove bottom thin wall portion of the second concave groove (not to mention the first concave groove) is plastically deformed (mainly) radially inward with respect to the outer peripheral surface of the pipe, and small in the axial direction. It bites in while forming a dent groove with dimensions, and exhibits a large pull-out resistance, sealing performance, and anti-rotation force. Further, even if the conventional sealing layer (reference numeral 47 in FIG. 20) is omitted, sufficient sealing performance (sealing performance) can be exhibited. That is, the points (iii) and (i) and (ii) to be improved can be solved.
Further, even when rotational torque acts on the pipe (according to claim 3), the rotation of the pipe can be reliably prevented at the position of the groove bottom thin wall portion of the second concave circumferential groove. As a result, there is no relative rotation between the plastic deformation portion of the thin groove bottom wall portion of the first concave circumferential groove and the biting portion of the outer peripheral surface of the pipe. And sealed.
Further, it is not necessary to cover the sealing layer, and furthermore, a sealing material such as rubber can be omitted, the durability is excellent, and the cost can be reduced. Of course, field work such as flaring, welding, and brazing is not necessary.
In particular, when the outdoor unit of the air conditioner falls, the pipe is twisted by about 90 °, and rotational torque acts on the pipe. In the present invention, the groove bottom thin wall portion of the second concave circumferential groove and the pipe The powerful rotation stop between the pipes prevents the rotation of the pipe, and at least the relative rotation between the thin wall of the bottom groove of the first concave groove (at the back) and the pipe (even a minute angle) does not occur. In addition, the sealing property (sealability) can be stably maintained over a long period of time.

It is sectional drawing which shows one Embodiment of this invention, The upper half part from an axial center line shows sectional drawing of a cap nut untightened state, and the lower half part from an axial center line is sectional drawing of a clamping completion state is there. One Example of a rotation prevention cylindrical body is shown, (A) is a front view, (B) is a cross-sectional side view. The other Example of a rotation prevention cylindrical body is shown, (A) is a front view, (B) is a cross-sectional side view. It is explanatory drawing of the principal part of a rotation prevention cylindrical body. It is principal part sectional drawing for demonstrating the sleeve for compression deformation. It is a principal part enlarged view of the sleeve for compression deformation. It is principal part expansion explanatory drawing which showed the positional relationship of the principal part of an uncompressed state. It is principal part expansion effect explanatory drawing which shows a compression state. FIG. 4 is an enlarged explanatory view showing only a main part of a compression sleeve in a compressed state. It is a perspective view explaining the test method which provides rotational torque to a pipe. It is perspective explanatory drawing for demonstrating the conventional problem and the advantage, effect | action, and effect of this invention. It is sectional drawing of a cap nut untightened state. It is sectional drawing which shows the state (state in the middle of sleeve compression) in the middle of a cap nut screwing. It is sectional drawing which shows a cap nut fastening completion state (sleeve compression state). It is principal part explanatory drawing, (A) is sectional explanatory drawing of a cover member, (B) is a half-ridge main part explanatory drawing of the sleeve for compression deformation, Comprising: The point has shown the taper surface. It is sectional drawing of the comparative example which shows a cap nut fastening completion state (sleeve compression state). It is principal part sectional drawing for demonstrating the effect | action (problem) of a comparative example. It is principal part sectional drawing for demonstrating the effect | action of this invention. 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.
Figure 1 shows an embodiment of the present invention, the upper half than the axial center line L ₀ state with non-clamping, axial center line L ₀
The lower half is a sectional view showing a tightening (connection) completed state. Further, FIGS. 12 to 14 are diagrams showing a sequential change from an untightened state to an intermediate state and then to a tightening (connection) completed state.

The refrigerant pipe joint structure shown in FIG. 1 and FIG. 12 to FIG. 14 includes a joint main body 1 integrally having a male screw 2 and a cap nut 3 screwed to the male screw 2. The metal pipe P is connected. As the metal pipe P is made of copper or aluminum, will be described first case (made of copper) copper tube P _Cu.
The copper pipe P _Cu and the pipe joint are connected without flaring the end portion 5 of the copper pipe P _Cu . The joint body 1 and the cap nut 3 are made of brass, for example. A refrigerant such as an air conditioner flows through the copper pipe P _Cu and the pipe joint.
At a 1 and 5, 7, for the copper tube P _Cu, a compressive deformation sleeve made of copper, the first concave peripheral groove 91 on the outer peripheral surface 8 two second concave peripheral groove 92 The concave circumferential groove 9 is provided. A second concave circumferential groove 92 is provided on the outer end side of the sleeve 7, and a first concave circumferential groove 91 is provided on the joint body 1 side. The compression deformation sleeve 7 is stored in the internal storage space 10 of the cap nut 3.

When the cap nut 3 and the male screw 2 of the joint body 1 are screwed together, the compression deformation sleeve 7 is changed from the upper half (free state) of the shaft center line L _{0 in} FIG. As shown in Fig. 14 through Fig. 12 through Fig. 13 and in Fig. 14 as shown in Fig. 14, it receives a compressive force (tightening force) F in the axial direction from the joint body 1 and the cap nut 3, groove bottom thin wall portion 13 is plastically deformed in the radial inward direction (see FIGS. 1 and FIGS. 8 and 14), which retaining fit bite from the outer peripheral surface 14 side of the copper tube P _Cu being inserted. That is, exhibit scratch抜力, to prevent pullout of the copper tube P _Cu. In this compressed state, small ridges 25 are also formed on the inner peripheral surface of the copper pipe _PCu .
The case where the first and second concave circumferential grooves 91 and 92 of the compression deformation sleeve 7 are substantially semicircular is illustrated in FIG. 1, FIG. 5, FIG. 7 and FIG. The cross-sectional shape may be U-shaped, and may be substantially V-shaped depending on the case.

The width dimension W of the concave grooves 91 and 92 decreases with compressive deformation (in the case of plastic deformation), as shown in the lower half of FIG. 1, or in FIG. 8, FIG. 14, and FIG. As shown, the groove back portions of the concave circumferential grooves 91 and 92 are in pressure contact with the groove side surfaces 15 and 15, and a narrow U shape or a narrow V shape is formed near the groove opening. (Although not shown in the drawing, the entire groove side surfaces 15 may be pressed against each other.)
6A and 6B, a small protrusion 23 having a locking step G is formed in the groove bottom thin wall portion 13 of the first concave circumferential groove 91 on the axial inward side. As shown in the lower half of FIG. 1, or as shown in FIGS. 13 and 14, it bites into the outer peripheral surface 14 of the copper pipe P _Cu in a compressed state, thereby increasing the pulling resistance of the copper pipe P _Cu (pipe P). And improve the sealing performance (sealing performance).

In the longitudinal cross-sectional shape of the inner peripheral surface 11 of the sleeve 7 shown in FIG. 5, the proximal end side of the small protrusion 23 is recessed in the straight portion 24, and the distal end side of the small protrusion 23 has a gentle shape. A taper 26 that decreases in diameter in the distal direction and a taper 27 that increases in diameter in the distal direction are sequentially formed. The diameter-expanded taper 27 is continuous with the straight portion 28 (having the same inner diameter), and the straight portion 28 is formed at the tip. It is open.
The position of the boundary line H between the straight portion 28 and the enlarged diameter taper 27 is preferably near the center of the width of the second concave circumferential groove 92. 50 is a non-rotating cylindrical body made of stainless steel (which is sufficiently harder than copper), and this non-rotating cylindrical body 50 is made of a thin stainless steel having a cut 51 as shown in FIG. The innermost edge of the C-shaped cylinder, which is inserted (internally) into the compression deformation sleeve 7 from the outer end side in the axial direction in advance and has a depth corresponding to the groove bottom thin wall portion 13 of the second concave circumferential groove 92. Part 50A has reached.
As shown in FIG. 2, the innermost edge portion 50A and the outermost edge portion 50B of the C-shaped cylindrical body 50 have pipe-cut (notch-shaped) recesses such as a rectangular shape (or U-shape). 52 is provided. Although not shown, a pipe biting convex portion (projecting piece portion) may be provided.
Detent cylindrical body axial dimension L ₅₀ of 50, of substantially equal to the depth of the straight portion 28 of FIG. 5 described above is desirable. In other words, the cylindrical body 50 is housed in the compression deformation sleeve 7 so that the innermost edge 50A of the cylindrical body 50 substantially matches up to the position of the boundary line H.
More specifically, as shown in FIG. 7, when the sleeve 7 is in an uncompressed state, the position in the axial direction of the innermost edge portion 50 </ b> A of the cylindrical body 50 is the groove side surface 15 near the tip of the second concave circumferential groove 92. The second concave circumferential groove 92 is preferably set within a range (1/2 · W) from a position half the groove width dimension W.

Then, when the cap nut 3 is screwed into the joint body 1 from the uncompressed state shown in the upper half of FIG. 1, the lower half of FIG. 1 and FIG. 8 (FIG. 14) are shown. As described above, in the final connection state, the groove bottom thin wall portions 13 of the first concave circumferential groove 91 and the second concave circumferential groove 92 are plastically deformed in a U shape or a V shape in the radial inward direction. Due to the plastic deformation of the groove bottom thin wall portion 13, in the second concave circumferential groove 92, the innermost edge portion 50A of the non-rotating cylindrical body 50 is also plastically deformed radially inward, and the innermost edge portion 50A is Corresponding to the vicinity of the minimum diameter portion of the groove bottom thin wall portion 13 plastically deformed in a U shape (V shape), it deeply digs into the outer peripheral surface 14 of the pipe P (copper pipe P _Cu ), and the arrow F _{50 in} FIG. It bites into the pipe P (copper pipe P _Cu ) with the extremely large pushing force (biting force) shown in. A reaction force F ₅₀ ′ having the same magnitude is generated from the pipe P (copper pipe P _Cu ) side.

When the innermost edge 50A of the cylindrical body 50 bites in by such a large pushing force (biting force), relative rotation between the cylindrical body 50 and the pipe P (copper pipe P _Cu ) is prevented. .
It should be noted that a portion of the sleeve 7 bites into the cut 51 on the pressure contact surface between the thin C-shaped cylindrical body 50 of hard stainless steel and the sleeve 7, and mutual rotation does not occur. In addition, there are many small ridges N (see FIG. 9) accompanying plastic deformation in the direction of diameter reduction and no mutual rotation occurs.
On the other hand, in the first concave circumferential groove 91, the small protrusions 23 bite into the outer peripheral surface 14 of the pipe P (copper pipe P _Cu ), exhibiting a strong pull-out resistance, and at the same time exhibiting a stable sealing performance (sealing performance). To do.

As described above, the case where the pipe P is the copper pipe P _Cu has been described. However, when the pipe P is the aluminum pipe P _Al , the material of the compression deformation sleeve 7 is aluminum from the viewpoint of electrolytic corrosion prevention, or Although copper which coat | covers the aluminum layer is used, the structure of other than this, an effect, and a function are the same as that of the copper pipe _PCu . (Therefore, duplicate explanation is omitted.)

Next, as in the other embodiment shown in FIG. 3, the innermost edge 50A and the outermost edge 50B have a C-shaped non-rotating cylindrical body 50 having a cut 51 (see FIG. 2). It is also preferable to form a large number of small irregularities. At this time, a square concave / convex waveform as shown in FIG. 4A is formed by knurling, punching or crushing, or a triangular triangular concave / convex waveform as shown in FIG. 4B is formed by similar processing. Alternatively, rough surface processing with minute irregularities may be performed by grinding or file processing as shown in FIG.
As shown in FIG. 18, not only the innermost edge 50A but also the outermost edge 50B of the non-rotating cylindrical body 50 bites into the outer peripheral surface 14 of the pipe P in the compressed state (sleeve). Therefore, when the pipe P tries to rotate around the shaft center line L ₀ , a strong detent stop force is exhibited. At this time, by having the cut 51, a part of the inner peripheral surface of the sleeve 7 bites into the cut 51, and the relative rotation between the sleeve and the cylindrical body 50 is strongly prevented. In addition, if the concave portion 52 and / or the convex portion are disposed symmetrically on the innermost and outer end edges 50A and 50B, an erroneous assembly of the cylindrical body 50 does not occur during assembly.

  As described above, according to the plastic deformation of the groove bottom thin wall portion 13 of the second concave circumferential groove 92, the anti-rotation function (grip function) (of the pipe P) is exhibited, and (naturally) the pipe P Exhibits pull-out resistance and sealing function (seal performance) against refrigerant. On the other hand, according to the plastic deformation of the groove bottom thin wall portion 13 of the first concave circumferential groove 91, the pull-out resistance of the pipe P is exhibited. However, with regard to the sealing function (seal performance) against the refrigerant, it is necessary to assist in the anti-rotation function (grip function) of the second concave groove 92 (described above). Hereinafter, this point will be described.

9 is an enlarged explanatory view of the main part of the compression deformation sleeve 7 when the pipe P is temporarily removed in the compression connection completed state of FIG. 14 or the compression connection completed state of the lower half of FIG. As apparent from FIG. 9, the inner peripheral surface of each groove bottom thin wall portion 13 in the first and second concave circumferential grooves 91 and 92 is plastically deformed into a U shape or a V shape. In this case, a large number of soot N is generated. 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 copper tube _PCu and the copper sleeve 7 are both soft and have a weak mutual rotation stopping force (grip function). Alternatively, the aluminum pipe P _Al and the aluminum sleeve 7 are both soft and have a weak mutual rotation stopping force (grip function).

When detent function by the addition of the second concave peripheral groove 92 side detent cylindrical member 50 (the grip function) is assumed not to exist, in the first concave peripheral groove 91 side, and a copper pipe P _Cu · aluminum tube P _Al Even if the sleeve 7 and the sleeve 7 are uneven, the pipe P easily rotates. If it does so, concavity and convexity will conversely generate a very small gap, and the refrigerant leaks to the outside.
Of course, in the first concave groove 91 itself, if there is no rotation-preventing cylindrical body 50, the U-shaped (or V-shaped) U-shaped (or V-shaped) groove bottom thin wall portion 13 of the first concave circumferential groove 91 is present. Similarly, the pipe P easily rotates when the unevenness caused by the ridge N of the plastic deformation portion and the reverse unevenness of the corresponding portion of the outer peripheral surface 14 of the pipe P enter.
As a result of the experiment, it has been found that when the pipe P is rotated by a minute angle of 1 ° to 2 ° from the state of the unevenness due to the minute ridges N, the refrigerant (gas) causes external leakage.

  In the present invention, by providing the innermost edge portion 50A of the non-rotating cylindrical body 50 corresponding to the groove bottom thin wall portion 13 of the second concave circumferential groove 92, a strong rotation prevention force (grip function) is provided. The refrigerant can be exerted by helping the first concave groove 91 and securing the plastic deformation site of the thin wall portion 13 of the groove bottom of the first concave groove 91 and the pipe P, thereby The first concave groove 91 can exhibit a sealing function (sealing performance) even for a gas such as a long period of time and under severe use conditions.

Next, FIG. 11 is a diagram showing an example of the usage state of the pipe joint structure according to the present invention, where the refrigerant pipes 18 and 18 are connected to the side surface of the box-type air conditioner outdoor unit 17— 11, indicated by black circles 19 and 19, the pipe joint according to the present invention is used.
The refrigerant pipe 18 corresponds to the above-described pipe P (copper pipe P _Cu or aluminum pipe P _Al ). In the outdoor unit 17 in the normal posture shown in FIG. When the pipe P is bent in a mold or the like, and an accident that falls in the direction of the arrow C for some reason, such as an earthquake or another object collides as shown in FIG. In the vicinity of the connection of the pipe P with the pipe joint, twisting in the direction of the arrow M occurs. Since the installation surface 20 of the outdoor unit 17 is generally horizontal, a twist of an angle β ₀ of about 90 ° occurs in the connection region between the pipe joint (see black circle 19) and the pipe P.

FIG. 10 is an explanatory perspective view of the refrigerant external leakage experiment in which the present inventor reproduced such an accident situation. That is, as shown in FIG. 10, as the pipe joint X, the conventional example shown in FIG. 20--that is, the one that does not include the non-rotating cylindrical body 50 of the present invention--as an embodiment of the present invention. 1 and 2 are fixed to the air conditioner outdoor unit 17 (fixed wall surface conceived) horizontally in a protruding manner, and the pipe P is bent with a minimum bend radius R ₁ . In a state of being bent vertically upward, it is gripped by a gripping tool at the boundary of the bend radius R ₁ and a straight shape (indicated by two triangular marks 21 and 21) and twisted in the direction of arrow M Was applied to the pipe, and the refrigerant was allowed to flow through the pipe joint X and the pipe P while applying the maximum use pressure in a normal use state, and an external leakage test was performed. As the 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 risk of external leakage of the refrigerant in the event of the outdoor unit 17 falling accident shown in FIG. When pipe twist is applied 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 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 and that stable and excellent sealing performance is exhibited.

In addition, returning to FIG. The joint body 1 has a tapered surface 48 at the distal end, and the compression deformation sleeve 7 has a pressure contact sealing tapered surface 49 having the same taper angle corresponding to the tapered surface 48 at the proximal end portion. The sealing by the press contact of both the tapered surfaces 48 and 49 is satisfactorily sealed as in the case of the flared joint of JIS B8607. In order to prevent the base end portion of the compression deformation sleeve 7 from generating excessively large diameter plastic deformation (in the radial outward direction) when both the tapered surfaces 48 and 49 are strongly pressed against each other, As can be seen in FIGS. 1 and 5, it has a reinforcing inner collar 7C.
In FIG. 1, the sleeve 7 for compressive deformation is formed with a cover metal 29 made of hard metal such as stainless steel in an outer fitting shape with a slightly smaller outer diameter except for the base end. Yes. 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.

  One feature of the present invention is that, as shown in FIGS. 8 and 18, etc., the sleeve 7 receives a compressive force F, and the groove bottom thin wall portion 13 has a U-shape in the radial inward direction ( (Or V-shape), the innermost edge 50A of the C-shaped detent cylindrical body 50 is strongly pressed (in the radial inward direction) in the vicinity of the maximum deformed portion of the minimum diameter. ) The innermost end edge portion 50A bites into the outer peripheral surface 14 of the pipe P and the outermost end edge portion 50B also bites into the pipe P (the outer peripheral surface 14 thereof) and the relative compression sleeve 7 It is configured to prevent rotation (stop rotation).

  As shown in FIG. 18 (and FIG. 14), the inner flange portion 3A of the cap nut 3 is formed with a tapered surface 3B, and the inner peripheral edge of the outer end inner flange portion 29A of the cover member 29 and the pipe P And a gap 54 is also provided between the inner peripheral surface of the inner flange portion 3A of the cap nut 3 and the pipe P so that the outermost edge 50B of the cylindrical body 50 is a gap. It makes it easy to sink into 53 and 54, helps to bite into the outer peripheral surface 14 of the pipe P, and plays the role of pushing inward in the radial direction.

  Since the cylindrical body 50 has the cut 51, the outermost end edge portion 50B surely bites into the pipe outer peripheral surface 14 while being reduced in diameter in the compressed state shown in FIGS. In addition, a portion of the inner surface of the sleeve 7 enters the cut 51, and the sleeve 7 and the cylindrical body 50 endure a strong rotational torque and do not slip.

The groove bottom thin wall portion 13 plastically deformed in a U shape (or V shape) by a small ridge N generated by the deformation in the diameter reducing direction as shown in FIG. 9, and the pipe outer peripheral surface 14 corresponding thereto, Even though they are meshed with each other, both materials are in pressure contact with soft materials such as copper and copper or aluminum and aluminum, as described in Fig. 11 (Fig. 10). If the twisting force of the pipe in the direction of the arrow M is applied, a slight rotational slip of 1 ° to 2 ° is generated, and the small ridge N passes through the gas (refrigerant) at this time. It is considered that a path is formed and external leakage is generated, and the present invention prevents such external leakage with a small thin wall (thickness 0).
.2mm or less) can be easily and stably prevented by the short cylindrical non-rotating cylindrical body 50.
In the present invention, it is another feature that the parts are combined with materials that do not cause an electric corrosion phenomenon. Another feature of the present invention is that no material that causes deterioration (corrosion) due to a refrigerant such as rubber or plastic is used. (It can also be said that welding and silver soldering work are completely unnecessary.)

The maximum feature point of the present invention will be described below. The groove bottom thin wall 13 of the first concave circumferential groove 91 on the axial inward side of the compression deformation sleeve 7 is first plastically deformed, and then the groove bottom thin wall of the second concave circumferential groove 92 on the axial outer side. The cover member Z for sequential control which plastically deforms the part 13 is provided. This sequential control cover member Z has a configuration in which the above-described cover member 29 for promoting rotational slip that is externally fitted to the compression deformation sleeve 7 is also used.
In other words, the sequential control cover member Z has a function of promoting relative rotational slip between the inner peripheral surface 3C of the cap nut 3 and the outer peripheral surface 8 of the compression deformation sleeve 7.

  More specifically, the compression deformation sleeve 7 is formed in the intermediate outer peripheral surface portion 55 between the first concave circumferential groove 91 and the second concave circumferential groove 92 as shown in FIGS. Thus, a tapered surface 56 that is reduced in diameter outward in the axial direction is formed. On the other hand, the sequential control cover member Z is externally fitted in correspondence with the inner flange portion 29A formed at the end portion in the axially outward direction and the tapered surface 56 of the compression deformation sleeve 7 in an uncompressed state ( It has a tapered surface 57 that is reduced in diameter in the axially outward direction. In FIG. 15, “dots” are added to show the tapered surfaces 56 and 57 in an emphasized manner. As described above, the present invention includes the sequential control means Y composed of the taper surface 56 of the compression deformation sleeve 7 and the taper surface 57 of the cover member Z. By the sequential control means Y, the first concave portion is provided. Plastic deformation is caused in the groove bottom thin wall portion 13 in order, with the circumferential groove 91 first and the second concave circumferential groove 92 behind.

Next, before describing the operation and operation of the sequential control means Y, a comparative example in which the sequential control means Y is not provided in FIGS. 16 and 17 will be described.
16 and 17, the compression deformation sleeve 77 has a straight circumferential surface without the taper surface 56 shown in FIG. 15B, and the cover member 99 has the structure shown in FIG. A straight cylindrical portion without the tapered surface 57 shown in A) is provided. When the cap nut 3 is screwed into the male screw 2, the two concave circumferential grooves 91 and 92 receive the compressive force F, and at the same time, the groove bottom thin wall portions 83 and 83 are moved radially inward (in the direction of diameter reduction). ) And bite into the outer peripheral surface 14 of the pipe P to form the biting recesses 78 and 79.
At this time, as the sleeve 77 is compressed, the first concave circumferential groove 91 moves by a small dimension L _1, and the groove bottom thin wall portion 83 (curved and deformed) as shown by the arrow R ₁ bites into the pipe outer circumferential surface 14. In close contact with the biting recess 78. However, with the compression of the sleeve 77, the second concave peripheral groove 92 moves the major dimension L _2. That is, the large dimension L ₂ is added, which is the sum of the reduction values of the axial dimension of the first concave circumferential groove 91 and the second concave circumferential groove 92. Therefore, the groove bottom thin wall portion 83 bites in while radially bending inward while cutting the pipe outer peripheral surface 14 as shown by an arrow R ₂₀ , thereby forming a biting recess 79 that is long in the axial direction.

  As described above, in the comparative example, the biting recess 79 that is long in the axial direction is formed while being cut on the outer peripheral surface 14, so that the sealing performance (seal performance) is lowered. Moreover, the biting convex portion of the thin wall portion 83 that bends and deforms the outer peripheral surface 14 (as described above) wears, loses sharpness, further reduces the sealing performance (sealing performance), and is resistant to pulling out. The force and the pipe rotation prevention force around the shaft center decrease.

In contrast to such a comparative example (FIGS. 16 and 17), in the present invention, when the cap nut 3 is screwed from the uncompressed state shown in FIG. 12, the tapered surface 57 of the cover member Z is compressed and deformed. The tightening force (compression force) indicated by the arrow F from the cap nut 3 is transmitted to the intermediate outer peripheral surface portion 55 of the compression deformation sleeve 7 while being in strong pressure contact with the tapered surface 56 of the sleeve 7 for compression. As a result, as indicated by an arrow R ₁ in FIG. 13, only the groove bottom thin wall portion 13 of the first concave circumferential groove 91 bites into the pipe P, while the second concave circumferential groove 92 receives almost no compressive force. (Without deformation), after moving in the direction parallel to the axis L ₀ (the direction of the arrow H), as shown in FIGS. 14 and 18, the groove bottom in the radial inward direction as shown by the arrow R ₂ The thin wall portion 13 bends and bites into the pipe P.

When the compressive force F is continuously applied from the cap nut 3 after the final bending deformation of the groove bottom thin wall portion 13 of the first concave circumferential groove 91 shown in FIG. 13, the tapered surface 57 of the cover member Z is (Because the material of the cover member Z is stainless steel with high rigidity and small elongation), the same diameter portion (straight portion) 58 as shown in FIG. Get on. 18 shows a state where the taper surface 57 of the cover member Z rides on the original same-diameter portion (straight portion) 58 indicated by the two-dot chain line of the compression deformation sleeve 7, and arrows R ₁ , R _The pressing force in _two directions is also increasing.

  The present invention is not limited to the above-described configuration, and can be freely changed. For example, as shown in FIGS. 1 and 12 to 14, the inner peripheral surface 3C of the cap nut 3 and the cover member Z (29) A small gap in the circumferential direction is formed between them, and the rigidity of the cover member Z (29) is increased, and a material having a small elongation is selected, thereby reducing the rotational torque of the cap nut 3 and lightly screwing It is also desirable to be able to perform. And it can prevent more reliably that the cover member Z rotates together.

  14 and 1 (lower half) showing the connection completion state, the innermost end of the cover member Z (29) abuts against the outer peripheral stepped portion 60 of the sleeve 7 and is pressed. For example, even if the concave circumferential grooves 91 and 92 are further crushed (compression deformation), the pressure contact force between the tapered surface 48 of the joint body 1 and the tapered surface 49 of the sleeve 7 is maintained, and the sealing performance (seal performance) here. Can hold.

Further, in the present invention, the co-rotation with the pipe P around the shaft center line L ₀ is reliably prevented by the non-rotating cylindrical body 50, whereby the first concave circumferential groove 91 and the second concave circumferential groove 92 are formed. A double seal of the bottom wall portions 13 and 13 of both grooves can be formed, and excellent sealing performance can be obtained.

  As described in detail above, the present invention includes a joint body 1 with a male thread and a cap nut 3 that is screwed onto the male thread 2 of the joint body 1. It is housed 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 body 1 are screwed together, the joint body 1 and the cap nut 3 compress in the axial direction. Refrigerant having a compression deformation sleeve 7 that receives the force F and plastically deforms the concave circumferential groove bottom thin wall portion 13 radially inward and bites in from the outer peripheral surface 14 side of the inserted metal pipe P to prevent it from being removed. In the pipe joint structure, the concave circumferential groove 9 includes a first concave circumferential groove 91 on the axial inward side and a second concave circumferential groove 92 on the axial outer side, and the first concave circumferential surface. The sequential control cap which causes the plastic deformation in order, with the groove 91 first and the second concave circumferential groove 92 behind. -Since the member Z is externally fitted to the compression deformation sleeve 7, the conventional problems (i), (ii), and (iii) shown in FIG. The sealing performance is stable and excellent for a long time. In addition, the sequence control is a simple structure and the pipe joint is compact.

  Further, the compression deformation sleeve 7 is formed with a tapered surface 56 whose diameter decreases in the axial outward direction at an intermediate outer peripheral surface portion 55 between the first concave peripheral groove 91 and the second concave peripheral groove 92. The sequential control cover member Z has an inner flange portion 29A at the end portion in the axial outer direction and a tapered surface 57 that is externally fitted in correspondence with the tapered surface 56 of the compression deformation sleeve 7 in an uncompressed state. Even if the number of parts is small and compact and simple, the second concave groove 92 is surely deformed in order after the first concave groove 91 is reliably deformed.

  Further, the innermost edge portion 50A reaches the depth corresponding to the concave circumferential groove bottom thin wall portion 13 of the second concave circumferential groove 92 by being inserted in advance from the axial outer end side of the compression deformation sleeve 7. C-type non-rotating cylindrical body 50 having a cut 51 made of stainless steel, and the cylindrical body 50 is used for pipe biting at the innermost edge 50A and the outermost edge 50B in the axial direction. Since it is the structure which has the recessed part 52 and / or a convex part, it can prevent reliably that a pipe joint rotates together with rotation of the pipe P by addition of a small component.

  Further, the sequential control cover member Z has a function of promoting relative rotational slip between the inner peripheral surface 3C of the cap nut 3 and the outer peripheral surface 8 of the compression deformation sleeve 7, thereby reducing the number of parts. This minimizes the need for rotation and prevents excellent co-rotation and ensures reliable sequential control.

1 (with external thread) joint body 2 external thread 3 cap nut 3C inner peripheral surface 7 compression deformation sleeve 8 outer peripheral surface 9 concave peripheral groove
91 1st groove
92 Second concave groove
10 Internal storage space
13 Recessed groove bottom thin wall
14 Outer surface
29A Inner buttock
50 Non-rotating cylindrical body
50A innermost edge
50B Outermost edge
51 cut
52 recess
55 Middle outer peripheral surface
56 Tapered surface
57 Tapered surface F Compression force (clamping force)
P Metal pipe for refrigerant Z Cover member for sequential control

Claims (4)

A joint body (1) with a male thread, and a cap nut (3) screwed onto the male thread (2) of the joint body (1), and an internal storage space (10) of the cap nut (3) And a concave groove (9) on the outer peripheral surface (8), and the joint body when the cap nut (3) and the male screw (2) of the joint body (1) are screwed together. (1) and an axial compression force (F) from the cap nut (3), the concave circumferential groove bottom thin wall portion (13) is plastically deformed radially inward, and the inserted metal pipe ( In the pipe joint structure for refrigerant having a compression deformation sleeve (7) that bites in from the outer peripheral surface (14) side of P) and prevents it from being removed,
The concave circumferential groove (9) has a first concave circumferential groove (91) on the axial inward side and a second concave circumferential groove (92) on the axial outer side, and the first concave circumferential groove ( The sequential control cover member (Z) for causing the plastic deformation is sequentially fitted on the compression deformation sleeve (7) in order, starting with 91) and after the second concave circumferential groove (92). A refrigerant pipe joint structure characterized by that. The compression deformation sleeve (7) has a tapered surface that is reduced in diameter in the axial outward direction at an intermediate outer peripheral surface portion (55) between the first concave circumferential groove (91) and the second concave circumferential groove (92). (56) is formed,
The sequential control cover member (Z) corresponds to the inner flange (29A) of the axially outer end and the tapered surface (56) of the compression deformation sleeve (7) in an uncompressed state. The refrigerant pipe joint structure according to claim 1, further comprising a taper surface (57) to be externally fitted.   The innermost edge portion (to the depth corresponding to the concave groove bottom thin wall portion (13) of the second concave circumferential groove (92) inserted in advance from the axial outer end side of the compression deformation sleeve (7) ( 50A) is provided with a C-shaped detent cylindrical body (50) having a stainless steel cut (51) to which the cylindrical body (50) has an innermost edge in the axial direction ( 3. The refrigerant pipe joint structure according to claim 1, wherein a pipe biting recess (52) and / or a protrusion is provided at 50 A) and the outermost edge (50 B).   The sequential control cover member (Z) promotes relative rotational slip between the inner peripheral surface (3C) of the cap nut (3) and the outer peripheral surface (8) of the compression deformation sleeve (7). The refrigerant pipe joint structure according to claim 1, 2 or 3.

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