JP5525897B2 - Pipe fitting - Google Patents

Description

  The present invention relates to a pipe joint used for connecting a metal connecting pipe such as a refrigerant pipe for a cold air conditioner or the like.

  As this type of pipe joint, the applicant previously proposed a pipe joint having a form using a ferrule as shown in FIG. 4 (see, for example, Patent Document 1). The right half in FIG. 4 shows a temporary tightening state diagram of the tightening nut 22, and the left half shows a state diagram when the tightening nut 22 is fully tightened. The pipe joint surrounds the entire circumference of a tubular joint body 21, a tightening nut 22 screwed into the male screw of the joint body 21, and a metal connecting pipe P inserted into the joint body 21. A cylindrical metal ferrule (clamping ring) 23 and a tapered surface 25 formed in the inner periphery of the joint body 21 so as to gradually expand outward in the axial direction. 4 is provided with a diameter reducing means for pressing the ferrule 23 in the diameter reducing direction, and the ferrule 23 pressed by the diameter reducing means is reduced in diameter while being plastically deformed. Thus, the configuration is such that the outer periphery of the connection pipe P is tightened in a form that is in close contact with the airtight / watertight state.

JP 2006-207795 A

As shown in the state diagram of the right half of FIG. 4, the pipe joint is previously set by inserting a ferrule 23 into the joint body 21 and then screwing the tightening nut 22 into the male thread of the joint body 21. It is assembled.
When connecting the connecting pipe P to this pipe joint, the leading end of the distal end side end P-1 of the connecting pipe P hits the pipe end stopper 26 inside the joint main body 21 by hand. Insert until Thereafter, by rotating the tightening nut 22 with a tool such as a spanner and finally tightening, the tip side portion 23a of the ferrule 23 is bitten into the connecting pipe P as shown in the state diagram of the left half in FIG. The connection pipe P is retained and sealed, and the connection work is completed.

  However, since the pipe joint inserts the connecting pipe P until the tip end portion P-1 of the pipe end contacts the pipe end stopper portion 26 in the joint body 21, the fastening nut 22 is finally tightened. As the tightening nut 22 is finally tightened, the tip side portion 23a of the ferrule 23 bites into the connecting pipe P, and the biting state is maintained. Since the distal end portion P-1 of the connection pipe P is located on the distal end side from the biting position of the distal end side portion 23a of the ferrule 23, the distal end portion P-1 of the connection pipe P is formed on the tube end stopper portion 26 while receiving an axial compressive load (buckling load). It will be pushed towards. Thereby, as shown by the broken line F in FIG. 4, the distal end side end portion P-1 of the connecting pipe P is displaced so as to bulge outward in the radial direction. However, the distal end P-1 of the connecting pipe P is located inward from the tapered surface 25 of the joint body 21, and is brought into contact with the inner peripheral surface 27 having an inner diameter substantially the same as the outer diameter of the connecting pipe P. Such a displacement is suppressed, and as a result, the tightening torque of the tightening nut 22 becomes high. For this reason, in a narrow place such as the back of the ceiling, there is a problem that the tightening operation of the tightening nut 22 with a tool such as a spanner is extremely difficult and the workability is lowered.

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to ensure the prevention of connection pipe sealing and sealing performance in a pipe joint using the ferrule as described above. However, it is an object of the present invention to provide a pipe joint that can reduce or reduce the tightening torque by a tool such as a spanner and can easily perform the tightening operation with a small tightening torque even in a narrow place such as a ceiling.

In order to make it easier to understand the contents of the invention, the invention described in claim 1 will be described with reference to the reference numerals attached to FIGS.
The invention according to claim 1 includes a joint body 1 having a receiving portion 4 into which a distal end side end portion P-1 of a connecting pipe P is inserted and a tube end stopper portion 5 provided in the inner portion of the receiving portion 4. The tightening nut 2 screwed and coupled to the external thread 11 provided on the outer periphery of the receiving portion 4 of the joint body 1 and loosely fitted on the outer periphery of the connection pipe P, and the receiving portion 4 of the joint body 1 are arranged inside the receiving portion 4. And a cylindrical ferrule 3 fitted to the outer periphery of the connection pipe P, and on the inner periphery on the axially outward side from the pipe end stopper portion 5 of the receiving port 4, the tip side portion of the ferrule 3 A first taper surface 7 for reducing the diameter of the tip portion by abutting 3a is formed to gradually expand outward in the axial direction, and is screwed onto the male screw 11 on the inner periphery of the tightening nut 2. A mating female screw 13 and a ferrule pressing step 14 provided on the axially outer end side of the female screw 13 are formed. The ferrule pressing step portion 14 pushes the rear end portion 3b of the ferrule 3 inward in the axial direction along with the screwing of the tightening nut 2, so that the front end side portion 3a of the ferrule 3 and the first tapered surface 7 are In a pipe joint that bites into the gap between the outer periphery of the connection pipe P and adheres to the outer periphery of the connection pipe P and the first tapered surface 7 in an airtight / watertight state,
On the first inner peripheral surface 6 between the narrowed side end 7a of the first tapered surface 7 and the tube end stopper portion 5 in the receiving portion 4, the tip side end portion P-1 of the connecting pipe P is provided. A connecting pipe escape recess 12 is formed to allow displacement outward in the radial direction .
The connecting pipe escape recess is characterized in that the radius is larger than the radius of the first tapered surface at the narrow side end of the first tapered surface .

  According to the above configuration, when the tightening nut 2 is tightened to the joint body 1, the ferrule pressing step portion 14 pushes the rear end portion 3b of the ferrule 3 inward in the axial direction, and the front end side portion 3a of the ferrule 3 is first. Since the first tapered surface 7 and the outer periphery of the connecting pipe P are bitten while being pressed inward in the radial direction by the tapered surface 7, the connecting pipe P is connected to the joint body 1 by this biting. It is connected to the state where it is prevented from coming off. Further, the distal end side portion 3 a of the ferrule 3 bites into the gap between the first tapered surface 7 of the joint body 1 and the outer periphery of the connecting pipe P, so that the outer periphery of the connecting pipe P and the first tapered surface 7 are hermetically sealed. -It adheres in a watertight manner and seals the gap between the joint body 1 and the connecting pipe P.

In particular, a connecting pipe escape recess 12 is formed on the first inner peripheral surface 6 between the narrowed end 7 a of the first tapered surface 7 and the pipe end stopper 5 in the receiving port 4. Therefore, as the tightening nut 22 is finally tightened, the distal end side portion 3a of the ferrule 3 bites into the connecting pipe P, and the leading end side end portion P-1 of the connecting pipe P is compressed in the axial direction in this biting state. It is pushed toward the tube end stopper 45 while receiving a load (buckling load). Accordingly, the distal end side end portion P-1 of the connecting pipe P is displaced into a shape that bulges outward in the radial direction as shown by a broken line F in FIG. 4 and fits into the connecting pipe escape recess 12. The distal end portion P-1 is allowed to move radially outward (the left half state diagram in FIG. 1, the left half state diagram in FIG. 2, the left half state diagram in FIG. 3). reference). Therefore, the tightening torque of the tightening nut 2 can be small, and the tightening operation can be performed smoothly and easily even in a narrow place such as the back of a ceiling or a spanner with a short handle.
The displacement of the distal end side end P-1 of the connection pipe P described above is caused by the connection pipe formed between the narrow end 7a of the first tapered surface 7 and the pipe end stopper portion 5 in the receiving port 4. Since it is absorbed by the escape recess 12, the above-described retaining and sealing of the connecting pipe P are not affected, and the above-described retaining and sealing performance of the connecting pipe P can be secured.

  As described in claim 2, the pipe joint according to the present invention is contracted to the rear end portion 3b by the contact of the rear end portion 3b of the ferrule 3 on the inner periphery of the axially outer opening end of the receiving portion 4. It is possible to adopt a configuration in which the second tapered surface 9 to which the radial action is applied is formed so as to gradually expand outward in the axial direction. According to this, as the tightening nut 2 is screwed, the rear end of the ferrule 3 immediately before the front end side portion 3a of the ferrule 3 finishes biting into the gap between the first tapered surface 7 and the outer periphery of the connecting pipe P. Since the portion 3b is pressed inward in the radial direction by the second tapered surface 9 and is subjected to diameter reduction deformation, there is a sealed state in which the rear end portion 3b of the ferrule 3 is in close contact with the outer periphery of the connection pipe P in an airtight / watertight state. can get. In other words, a double-sealed state is obtained together with the seal by the tip side portion 3a of the ferrule 3.

  According to the present invention, the connection pipe escape recess is formed on the first inner peripheral surface between the narrow side end of the first taper surface and the pipe end stopper portion in the receiving portion, and this connection pipe relief is formed. The concave part allows the distal end of the connecting pipe to move radially outward, so that the connecting pipe can be prevented from being pulled out and the sealing performance can be secured. There is an advantage that the tightening work can be easily performed.

1 is a half-broken cross-sectional view of a pipe joint showing an embodiment of the present invention. FIG. 6 is a half cutaway cross-sectional view of a pipe joint showing another embodiment. FIG. 6 is a half cutaway cross-sectional view of a pipe joint showing still another embodiment. It is a half notched cross-sectional view of a conventional pipe joint.

  Preferred embodiments of the present invention will be described with reference to the drawings. The right half in FIG. 1 shows a temporary tightening state diagram of the tightening nut, and the left half shows a state diagram when the tightening nut is fully tightened. In FIG. 1, the pipe joint according to the present invention includes a joint body 1, a tightening nut 2, and a ferrule 3. The connecting pipe P connected by this pipe joint is made of a metal such as a copper pipe or a stainless pipe, or a resin.

  As shown in FIG. 1, the joint body 1 is formed in a cylindrical shape, and a receiving portion 4 into which the distal end side end portion P-1 of the connecting pipe P is inserted is opened at both ends thereof. In the inner part of the receiving part 4, in the order from the inner side to the outer side in the axial direction, an annular pipe end stopper part 5 and an inner diameter larger than the pipe end stopper part 5 on both axial sides of the stopper part 5. A first inner peripheral surface 6 to be formed, a first tapered surface 7 formed in a gradually expanding shape from the outer end in the axial direction of the first inner peripheral surface 6 toward the outer side in the axial direction; A second inner peripheral surface 8 that is continuous with the axial outer end of the first tapered surface 7 and that has an inner diameter larger than that of the first inner peripheral surface 6, and a receiving portion 4. The second tapered surface 9 is formed so as to gradually expand from the axially outer end of the second inner peripheral surface 8 toward the axially outer side. . The gradient of the second tapered surface 9 is set larger than that of the first tapered surface 7. A polygonal tool hooking portion 10 on which a tool such as a spanner is hung is formed at an intermediate position in the axial direction on the outer periphery of the joint body 1, and a male screw 11 is formed at a position corresponding to the outer periphery of the receiving portion 7.

In the first inner peripheral surface 6 between the narrowed side end 7a of the first tapered surface 7 and the tube end stopper portion 5 in the receiving port portion 4, the diameter of the distal end side end portion P-1 of the connection pipe P is provided. A connecting pipe escape recess 12 is formed to allow displacement outward in the direction. As shown in FIG. 1, the connecting pipe relief recess 12 has a straight cross-sectional shape, and is connected to the connecting pipe P inserted into the receiving port 4 before the fastening nut 2 is finally tightened. Before the distal end portion P-1 is displaced, the distal end portion P-1 of the connecting pipe P is radially outward from the outer peripheral surface of the distal end portion P-1 of the connecting pipe P. A bending space for allowing displacement is formed. The length of the line segment from the center of the connection pipe P (the center of the receiving port 4) to a point on the inner surface of the connection pipe escape recess 12 (the radius of the connection pipe escape recess 12) d1 is the connection pipe before displacement. It is set larger than the radius d2 of P. The radius of the connecting pipe escape recess 12 is larger than the radius of the first tapered surface 7 at the narrowed end 7 a of the first tapered surface 7.

  On the other hand, the tightening nut 2 has a female screw 13 that engages with the male screw 11 of the joint body 1 on the inner periphery thereof, and is directed radially inward so as to be orthogonal to the axial center on the axially outer end side of the female screw 13. A ferrule pressing step 14 is provided, and a connecting pipe insertion portion 15 into which the connecting pipe P can be inserted is provided on the outer side in the axial direction than the ferrule pressing step 14. As shown in FIG. 1, the connecting pipe insertion portion 15 has a linear cross-sectional shape.

  The internal thread 13 of the tightening nut 2 is formed with an anti-friction layer (not shown, the same applies hereinafter). The antifriction layer can be formed by baking and painting a paint type antifriction material in which molybdenum disulfide powder is dispersed in an organic or inorganic binder. Further, the anti-friction layer can be formed by coating an anti-friction material such as a fluororesin or applying chrome plating. Such an anti-friction layer is also formed on the ferrule pressing step 14 of the tightening nut 2.

  The ferrule 3 is formed in a cylindrical shape having an outer diameter that is slightly smaller than the inner diameter of the second inner peripheral surface 8 of the joint body 1 and an inner diameter that is slightly larger than the outer diameter of the connecting pipe P. The outer periphery of the front end side portion 3a of the ferrule 3 is formed as a tapered tapered surface 16, and the rear end portion 3b is formed in a circular cross section. The ferrule 3 is made of metal such as brass or stainless steel. The stainless steel ferrule 3 can correspond to a connection pipe P made of a copper tube or a stainless steel pipe, and the brass ferrule 3 can correspond to a connection pipe P made of a copper tube. .

  Next, one point for connecting the connecting pipe P will be described. As shown in the right half in FIG. 1, the ferrule 3 is inserted into the receiving port 4 of the joint body 1 from the distal end side 3 a in advance, and the female screw 13 of the tightening nut 2 is inserted into the male screw 11 of the joint body 1. Screw together to temporarily assemble. At this time, since the tapered surface 16 having a tapered shape is formed on the outer periphery of the distal end side portion 3 a of the ferrule 3, it is easy to insert from the inside of the receiving portion 4 to the first tapered surface 7. In this temporarily assembled state, the tip end of the front end side portion 3a of the ferrule 3 abuts on the first tapered surface 7 of the joint body 1, and the rear end portion 3b protrudes rearward from the receiving portion 4. Further, the ferrule pressing step portion 14 of the tightening nut 2 comes into contact with a part of the circumference of the rear end portion 3 b of the ferrule 3 with a circular cross section in a line contact state. The front end surface 2 a of the tightening nut 2 is located at a position separated rearward from the one side end surface 10 a of the tool hook 10 of the joint body 1.

  Subsequently, in the pipe joint temporarily assembled in this way, the tip end part P-1 of the connection pipe P is inserted into the receiving part 4 of the joint body 1 from the tightening nut 2. At this time, until the distal end side end P-1 of the connection pipe P passes through the connection nut relief recess 12 of the tightening nut 2, the ferrule 3, and the first inner peripheral surface 6 in order, and hits the pipe end stopper 5 Plug in. After that, a tool such as a spanner is hung on the tool hook 10 of the joint body 1 to prevent the joint body 1 from rotating, and then the tightening nut 2 is rotated in the tightening direction with another tool such as a spanner and finally tightened. To do. Then, the tightening nut 2 is screwed, and as shown in the left half of FIG. 1, the front end surface 2 a of the tightening nut 2 comes into contact with the one side end surface 10 a of the tool hook 10, and at the same time, the ferrule pressing step portion 14. Comes into contact with the outer end surface 4 a of the receiving portion 4. Since the anti-friction layer is formed on the internal thread 13 of the tightening nut 2, the friction between the contact surfaces of the internal thread 13 and the external thread 11 can be reduced, and the tightening nut 2 can be easily attached with a small operating force even with a short spanner or the like. It can be turned and has excellent workability.

  As the tightening nut 2 is screwed, the rear end portion 3b of the ferrule 3 is pushed inward in the axial direction by the ferrule pressing step portion 14, whereby the ferrule 3 is propelled inward in the axial direction. The distal end side portion 3a is pressed radially inward by the first taper surface 7 and is subjected to a diameter-reducing deformation so as to bite into the gap between the first taper surface 7 and the outer periphery of the connecting pipe P. The outer periphery of the connecting pipe P and the first tapered surface 7 are in close contact with each other in an airtight / watertight state. Further, immediately before the front end side portion 3 a of the ferrule 3 finishes being wedged into the gap between the first tapered surface 7 and the outer periphery of the connecting pipe P, the rear end portion 3 b of the ferrule 3 is radiated in the radial direction by the second tapered surface 9. Since it is pressed inward to reduce its diameter, the rear end 3b of the ferrule 3 is in close contact with the outer periphery of the connecting pipe P in an airtight and watertight state.

  Further, since the ferrule pressing step portion 14 of the tightening nut 2 is in line contact with the rear end portion 3b of the ferrule 3, the tightening nut 2 is easily slidable with respect to the ferrule 3, and with respect to the rear end portion 3b of the ferrule 3. The ferrule 3 can be pushed in while idling. That is, the rotational force of the tightening nut 3 is not easily transmitted to the connection pipe P through the ferrule 3, and the connection pipe P can be well prevented from rotating together when the tightening nut 2 is tightened. Further, since the anti-friction layer is formed on the ferrule pressing step portion 14 of the tightening nut 2, it is further slippery coupled with the line contact with the rear end portion 3 b of the ferrule 3, and the connecting pipe P is shared. It is possible to prevent rotation more reliably.

  In this way, when the tightening nut 2 is tightened, the distal end side portion 3a of the ferrule 3 is deformed in a reduced diameter and bites into the gap between the first tapered surface 7 and the outer periphery of the connecting pipe P, so that the connecting pipe P becomes the joint body. 1 is connected in a state of being prevented from being detached from the receiving portion 4. Further, the tip side portion 3a of the ferrule 3 bites into the gap between the first taper surface 7 and the outer periphery of the connection pipe P so that the outer periphery of the connection pipe P and the first taper surface 7 are in an airtight / watertight state. By closely contacting, the clearance between the inner periphery of the ferrule 3 and the outer periphery of the connecting pipe P and the clearance between the outer periphery of the ferrule 3 and the first tapered surface 7 of the joint body 1 are sealed in an airtight and watertight manner. Further, the inner periphery of the rear end portion 3b of the ferrule 3 is in airtight / watertight contact with the outer periphery of the connecting pipe P, and the outer periphery of the rear end portion 3b is in airtight contact with the second tapered surface 9 Is obtained. In other words, a double-sealed state is obtained together with the seal by the tip side portion 3a of the ferrule 3.

Further, as the tightening nut 22 is fully tightened, the distal end side portion 23a of the ferrule 23 bites into the connection pipe P, and the distal end side end portion P-1 of the connection pipe P is compressed in the axial direction in this biting state. While being subjected to (buckling load), it is pushed toward the tube end stopper portion 26. Thereby, when the displacement of the shape which the front end side end part P-1 of the connection pipe P expands radially outward as shown by the broken line F in FIG. 4 is shown in the state diagram of the left half in FIG. As described above, the distal end portion P-1 of the connecting pipe P is fitted into the connecting pipe escape recess 12 so that the distal end end portion P-1 of the connecting pipe P is allowed to move radially outward. Therefore, the tightening torque of the tightening nut 2 can be small, and the tightening operation can be performed smoothly and easily even in a narrow place such as the back of a ceiling or a spanner with a short handle.
Further, the displacement of the distal end portion P-1 of the connection pipe P is for releasing the connection pipe formed between the narrow end 7a of the first taper surface 7 in the receiving port 4 and the tube end stopper portion 5. Since it is absorbed by the concave portion 12, it does not affect the above-described retaining and sealing of the connecting pipe P, and the above-described retaining and sealing performance of the connecting pipe P can be ensured.

In the above embodiment, the connecting pipe relief recess 12 has a linear cross-sectional shape as shown in FIG. 1, but is not limited to such a shape. For example, FIG. As shown, it may be formed in a concave arc shape, or may be formed in a “<” shape as shown in FIG. 3. The radius of the connecting pipe escape recess 12 is larger than the radius of the first tapered surface 7 at the narrowed end 7 a of the first tapered surface 7.
In the above embodiment, the rear end 3b of the ferrule 3 is formed in a circular cross section. However, the shape is not limited to such a shape. For example, at least a vertex that makes line contact with the ferrule pressing step 14 and a connection You may form in the polygon which has the vertex contact | abutted on the outer periphery of the pipe | tube P. FIG. In this case, it is preferable that the second tapered surface 9 is formed at the rear end portion of the polygonal cross section having an apex that abuts against the tapered surface 9. The second tapered surface 9 is not always necessary. Further, the receiving port 4 may be provided at least at one end of the joint body 1. Further, the anti-friction layer may be formed only on the male screw 11, or may be formed on both the male screw 11 and the female screw 13.

Moreover, in the said Example, although the joint main body 1 demonstrated the case where it was the same diameter socket type, ie, the type which can connect the connection pipes of the same diameter, the structure of the joint main body 1 is not restricted to this. For example, a different-diameter socket type that can connect tubes having different diameters may be used.
Further, the present invention can be similarly applied to the case where the joint body 1 is an elbow or a T type other than the socket type shown in the drawing.

P connecting pipe P-1 tip side end portion 1 joint body 2 clamping nut 3 ferrule 3a tip end side portion of ferrule 3b rear end portion of ferrule 4 receiving portion 5 pipe end stopper portion 6 first inner peripheral surface 7 first Taper surface 8 second inner peripheral surface 9 second taper surface 11 male screw 12 connecting pipe relief recess 13 female screw 14 ferrule pressing step

Claims (2)

A joint body having a receiving portion into which a distal end side end portion of a metal connecting pipe is inserted and a tube end stopper portion provided inside the receiving portion, and provided on an outer periphery of the receiving portion of the joint body A tightening nut that is screwed into a male screw and is loosely fitted to the outer periphery of the connection pipe, a cylindrical ferrule that is disposed inside the receiving portion of the joint body and is fitted to the outer periphery of the connection pipe, With
A first taper surface that applies a diameter reducing action to the distal end portion by abutment of the distal end side portion of the ferrule is formed axially outwardly on the inner periphery of the receiving end portion on the axially outer side from the tube end stopper portion. It is formed to gradually expand toward the
A female screw that is screwed to the male screw and a ferrule pressing step provided on the axially outer end side of the female screw are formed on the inner periphery of the tightening nut, and the ferrule pressing step is screwed on the tightening nut. The rear end portion of the ferrule is pushed inward in the axial direction as it advances, so that the front end side portion of the ferrule bites into the gap between the first tapered surface and the outer periphery of the connection tube, and the outer periphery of the connection tube and the first In a pipe joint that is in close contact with the taper surface of 1 in an airtight state,
On the first inner peripheral surface between the narrowed side end of the first tapered surface and the tube end stopper portion in the receiving port portion, a radially outward displacement of one end portion of the connection tube is provided. A recess for connecting pipe escape to allow is formed ,
The pipe joint according to claim 1, wherein a radius of the connecting pipe escape recess is larger than a radius of the first tapered surface at a narrowed end of the first tapered surface .   On the inner periphery of the axially outer opening end of the receiving portion, a second taper surface that applies a diameter reducing action to the rear end portion by contact of the rear end portion of the ferrule gradually expands outward in the axial direction. The pipe joint according to claim 1, which is formed in a shape.

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