JP2024005928A - Metal pipe joint - Google Patents

Abstract

To provide a metal pipe joint with improved retaining performance without increasing insertion resistance of a metal pipe into a joint.SOLUTION: A metal pipe joint includes a lock ring 3 and a chuck ring 4 within a cylindrical body part 2. The lock ring 3 with its first claw part 32 biting into an outer peripheral part of a metal pipe P presses the chuck ring 4 toward the front side in a pipe insertion direction in the case of such a displacement of the metal pipe P coming off of the cylindrical body part 2. In the chuck ring 4, immediately after metal P is inserted, a second claw part 42 thereof is in contact with an outer peripheral surface of the metal pipe P without biting, and as the diameter of the chuck ring 4 is reduced under the pressure of the lock ring 3, the second claw part 42 bites into the outer peripheral part of the metal pipe P to prevent it from coming off.SELECTED DRAWING: Figure 1

Description

The present invention relates to a metal pipe joint used when connecting metal pipes such as copper pipes.

As a metal pipe joint, for example, a structure shown in Patent Document 1 has been proposed. This joint is provided with a lock ring having a claw portion that prevents the metal tube from coming off from the joint. The lock ring exerts its ability to prevent it from falling out by biting into the outer periphery of the inserted metal tube.

By the way, especially when metal pipes are used as refrigerant pipes, the operating pressure is higher than that of other gas pipes or water pipes, so high slip-out prevention performance is required.

In order to achieve high retaining performance, it is possible to increase the number of lock rings. However, since the lock ring bites into the outer periphery of the metal tube, a biasing force acts in the radial direction, so increasing the number of lock rings increases the insertion resistance of the metal tube into the joint, making the insertion work difficult. It becomes difficult to do. If the insertion work is difficult to perform, there is a possibility that the metal tube will be inserted incompletely.

JP 2019-120309 Publication

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal pipe joint with improved retaining performance without increasing insertion resistance of the metal pipe into the joint.

One configuration of the present invention includes a cylindrical body portion that receives an inserted metal tube, a lock ring disposed inside the cylindrical body portion, and a lock ring that is located inside the cylindrical body portion and that is closer to the lock ring than the lock ring. a chuck ring disposed on the front side in the insertion direction; and a chuck ring disposed inside the cylindrical body portion on the front side in the tube insertion direction than the lock ring and the chuck ring, and abuts on the outer circumferential surface of the metal tube in the inserted state. a leak-proof ring in contact with the cylindrical body part, a ring arrangement recess into which the lock ring and the chuck ring are fitted, and the ring arrangement recess is provided on the inner periphery on the back side in the tube insertion direction. , the lock ring has a first surface that comes into contact with the lock ring immediately after the tube is inserted, and a second surface that is smaller in diameter than the first surface on the inner periphery on the front side in the tube insertion direction; The chuck ring is provided with a first claw portion that faces the tube insertion direction and bites into the outer peripheral portion of the metal tube immediately after, and the chuck ring is capable of contracting in diameter with respect to the axis of the cylindrical body portion, and The lock ring includes a pressing portion that can come into contact with the inner periphery of the ring arrangement recess and a second claw portion that protrudes in a radially inward direction, and the lock ring is configured to prevent the metal tube from coming out of the cylindrical body portion. When the displacement occurs, the chuck ring is pressed toward the front side in the tube insertion direction, and the chuck ring is in contact with the first surface immediately after insertion, and the second claw portion is in contact with the outer peripheral surface of the metal tube. The tube is pressed by the lock ring and moves toward the front in the tube insertion direction, causing the pressing portion to come into contact with the second surface and contracting the diameter. The metal pipe joint is such that the second claw part engages with the outer peripheral part of the metal pipe.

According to this configuration, the force of the metal tube trying to come out of the cylindrical body part causes the diameter of the chuck ring to be reduced by the second surface of the cylindrical body part and the pressing part of the chuck ring, and accordingly, the second claw part gets caught in the outer periphery of the metal tube. For this reason, the lock ring's ability to prevent it from coming off can be complemented by the chuck ring's engagement.

Further, in the chuck ring, the second claw portion may be provided at a position overlapping the pressing portion in the tube insertion direction.

According to this configuration, when the pressing part of the chuck ring comes into contact with the second surface of the cylindrical body part, the diameter of the chuck ring is reduced, and the generated force directed in the radial direction is directly transferred to the second claw part. The force is transmitted to cause the second claw portion to bite into the outer periphery of the metal tube.

Further, the chuck ring includes a main body that revolves around the axis of the cylindrical body, the second claw extends radially inward from the main body, and the second claw is used for inserting a pipe into the tube. It can have a surface including a component along the direction.

According to this configuration, the second claw portion having a surface including a component along the tube insertion direction can be made to bite into the outer circumferential portion of the metal tube in the tube insertion direction that is opposite to the withdrawal direction, so that it is strongly prevented from coming off. It can exert its effect.

Furthermore, a spacer may be provided between the lock ring and the chuck ring, which abuts on both.

According to this configuration, when the metal tube is displaced from the cylindrical body portion, the displacement is reliably transmitted to the chuck ring via the lock ring and the spacer.

According to the configuration of the present invention, the prevention of the lock ring from coming off can be supplemented by the biting of the chuck ring. Therefore, it is possible to provide a metal pipe joint with improved retaining performance without increasing the insertion resistance of the metal pipe into the joint.

1 is a radial cross-sectional view showing a state of a metal pipe joint according to an embodiment of the present invention before a pipe is inserted. FIG. 2 is a radial cross-sectional view of the metal pipe joint (when a pull-out load is applied to the metal pipe after insertion). The lock ring used in the metal pipe joint is shown, with (a) being a front view and (b) being a right side view (partially shown in radial cross section). The chuck ring used in the metal pipe joint is shown, in which (a) is a front view and (b) is a right side view (partially shown in radial cross section). A spacer used in the metal pipe joint is shown, in which (a) is a front view and (b) is a right side view (partially shown in radial cross section). 3 is an enlarged view of the portion surrounded by VI in FIG. 2. FIG.

First, one embodiment of the present invention will be described. The metal pipe P to be connected is indicated by a two-dot chain line in FIG. 2, and is, for example, a copper pipe for refrigerant (defined in JIS H 3300).

A metal pipe joint 1 (hereinafter referred to as "joint") of this embodiment is configured as shown in FIG. 1. As shown in the figure, the joint 1 has a symmetrical shape in the axial direction. The configuration of each part will be explained below by focusing on one side in the axial direction (the left side shown in Figure 1), but the other side in the axial direction (the right side in Figure 1) is also the same. It is said to be composed of The joint 1 includes a cylindrical body part 2 that receives the end of the inserted metal pipe P, a lock ring 3 disposed inside the cylindrical body part 2, and a lock ring 3 disposed inside the cylindrical body part 2 from the lock ring 3. A chuck ring 4 disposed on the front side in the tube insertion direction (on the left side in the figure), a spacer 5 interposed between the lock ring 3 and the chuck ring 4 and in contact with both, and a spacer 5 located inside the cylindrical body 2. A leak-proof ring (specifically, an O-ring 6 made of soft resin such as rubber) that is arranged on the front side in the tube insertion direction than the lock ring 3 and the chuck ring 4 and comes into contact with the outer peripheral surface of the metal tube P in the inserted state. , is provided. At least the lock ring 3 and chuck ring 4 are combined to form a retaining mechanism 11. The retaining mechanism 11 of this embodiment is configured by combining two lock rings 3, one chuck ring 4, and two spacers 5 as shown in the figure.

The cylindrical body portion 2 is a cylindrical member formed so as to have an axis extending linearly in the left-right direction as shown in the figure. The cylindrical body portion 2 includes a main body portion 21 and a lid portion 22. A female thread is formed on the inner periphery of the main body part 21, into which a cylindrical lid part 22 is screwed. An O-ring 23 is provided between the main body part 21 and the lid part 22 to prevent liquid leakage. The metal pipe P to be connected in this embodiment (the inserted state is shown by the two-dot chain line in FIG. 2) is inserted into the cylindrical body portion 2 from both sides in the axial direction (left and right in the figure). The metal tube P passes through the lid portion 22 and comes into a state in which the tip thereof comes into contact with a step 211 formed inside the main body portion 21 .

The inner periphery of the cylindrical body part 2 (specifically, extending between the main body part 21 and the lid part 22) is provided with a ring arrangement recess 24 into which the lock ring 3 and the chuck ring 4 are fitted. The ring arrangement recess 24 is provided all around the circumferential direction. The ring arrangement recess 24 includes a back vertical surface 241 on the back side in the tube insertion direction (right side in the figure) that comes into contact with the lock ring 3 immediately after the tube is inserted. The back vertical surface 241 is a plane perpendicular to the axis of the cylindrical body portion 2 . The rear vertical surface 241 is formed on the main body portion 21 . In addition, the inner circumferential surface provided all around the circumferential direction of the ring arrangement recess 24 has a back side circumferential surface 242 as a first surface and a second surface adjacent to the near side of the back side circumferential surface 242 in the tube insertion direction. This is the front side peripheral surface 243 of. Both the back circumferential surface 242 and the front circumferential surface 243 have a perfect circular cross-sectional shape perpendicular to the axial direction, and are parallel to the axial direction. The protrusion 43 of the chuck ring 4 as a pressing part initially comes into contact with the back circumferential surface 242, but when a pull-out load is applied to the metal tube P, the chuck ring 4 moves and the protrusion 43 moves to the front side. It comes into contact with the peripheral surface 243. Note that, unlike this embodiment, the pressing portion (projection portion 43) may be configured so as not to come into contact with the inner circumferential surface of the ring arrangement recess 24 until the metal tube P is subjected to a pulling load. The inner circumferential surface 242 is formed on the main body portion 21 . Further, the front side circumferential surface 243 is formed on the lid portion 22. The front circumferential surface 243 is formed to have a smaller diameter than the rear circumferential surface 242. Therefore, a step is formed between the back side circumferential surface 242 and the near side circumferential surface 243. A chamfered portion 244 is formed in this step. The chamfered portion 244 has a tapered surface that is inclined at a constant angle. The radial dimension decreases from the back circumferential surface 242 to the near side circumferential surface 243 via the chamfered portion 244. For this reason, the diameter of the chuck ring 4 moving from the back side circumferential surface 242 to the near side circumferential surface 243 is reduced.

The lock ring 3 has a form as shown in FIGS. 3(a) and 3(b), and is formed by bending a plate-shaped body. The lock ring 3 is made of a harder material than the metal tube P. In this embodiment, it is made of a metal material harder than the metal tube P. The lock ring 3 integrally includes a main body portion 31 and a first claw portion 32. The main body part 31 is an annular part, and is an L-shaped part in a radial cross section, in which a flat part perpendicular to the axis of the cylindrical part 2 and a cylindrical part surrounding the axis are integrated. It has Since it is L-shaped, the main body 31 is less likely to be twisted than, for example, a flat plate, and has excellent shape retention. The first claw portion 32 extends radially inward from the main body portion 31 . Specifically, as shown in FIG. 3(b), it extends obliquely toward the tube insertion direction as it goes in the radial inward direction. As shown in FIG. 3(a), the first claw portions 32 are formed intermittently at regular intervals in the circumferential direction. The radially inner portion of the first claw portion 32 is connected to the outer peripheral portion of the metal tube P immediately after insertion (strictly speaking, after the moment when the metal tube P is about to be displaced from the cylindrical body portion 2). , face the tube insertion direction and bite. Although the first claw portion 32 of this embodiment has a substantially semicircular shape as shown in the drawing, it can have various shapes as long as it can be bitten into the outer circumferential portion of the metal tube P. . In this embodiment, of the two lock rings 3, the one on the back side in the insertion direction is placed singly in the ring placement recess 24. As shown in FIG. 1, the spacer 5 on the front side in the insertion direction is arranged so as to fit into the L-shaped portion of the main body 31. The protruding portion 52 of the spacer 5 is arranged along the first claw portion 32.

The chuck ring 4 is formed into a C shape when viewed in the axial direction, as shown in FIG. 4(a). Therefore, the diameter of the cylindrical body portion 2 can be easily reduced with respect to the axis. Specifically, the diameter can be reduced according to the difference in the diameter of the inner circumferential surface (back side circumferential surface 242, front side circumferential surface 243) of the ring arrangement recess 24 that contacts the chuck ring 4 on the radially outer side. The chuck ring 4 is made of a material harder than the metal tube P (copper tube in this embodiment). In this embodiment, it is made of a metal material harder than the metal tube P. The chuck ring 4 includes a main body 41 that revolves around the axis of the cylindrical body 2, a second claw 42 that extends radially inward from the main body 41, and a protrusion 43 that projects radially outward from the main body 41. Equipped with. In this embodiment, the main body part 41 is larger than the second claw part 42 in terms of the dimension in the axial direction. Therefore, the second claw portion 42 protrudes radially inward from a portion of the inner circumferential surface of the main body portion 41. The second claw portion 42 has a sharp tip. As shown in FIG. 2, when the metal tube P is displaced from the cylindrical body portion 2, the second claw portion 42 bites into the outer circumference of the metal tube P as the chuck ring 4 contracts in diameter. It's crowded.

Further, the second claw portion 42 protrudes radially inward from the end of the main body portion 41 on the near side in the tube insertion direction. Note that the protrusion 43 is also formed at a radially outer portion of the end of the main body 41 on the near side in the tube insertion direction. The protrusion 43 and the second claw 42 are provided at overlapping positions in the axial direction (see FIG. 6). Due to this positional relationship, the chuck ring 4 changes from the state in which it is in contact with the back side circumferential surface 242 due to the force generated when the metal tube P tries to come out of the cylindrical body part 2 to the back side circumferential surface 242. The chuck ring 4 changes to a state in which it is in contact with the front circumferential surface 243, which has a smaller diameter compared to The force directed in the radially inward direction is directly transmitted to the second claw portion 42, and can be used as a force for the second claw portion 42 to bite into the outer peripheral portion of the metal tube P.

In this embodiment, the radial cross-sectional shape of the second claw portion 42 is a wedge shape that becomes narrower toward the radial inward direction. An end surface 421 of the second claw portion 42 on the back side in the tube insertion direction is a surface (vertical surface) perpendicular to the axis of the cylindrical body portion 2 . On the other hand, the end surface 422 on the near side in the tube insertion direction is a slope that faces toward the back side in the tube insertion direction as it goes radially inward. That is, the second claw portion 42 has a surface (the end surface 422 that is the slope) including a component along the tube insertion direction. Due to the shape of the second claw part 42 having a surface including a component along the tube insertion direction, the second claw part 42 is attached to the outer peripheral part of the metal tube P as the diameter of the second claw part 42 is reduced. Since it can be made to bite in the direction of tube insertion, which is the opposite direction, it can exert a strong retaining effect.

The protrusion 43 is a protrusion that extends along the circumferential direction within the range where the main body 41 exists. The radial cross-sectional shape of the protrusion 43 is semicircular. Therefore, the outer peripheral shape of the protrusion 43 is not sharp but curved. Therefore, it is possible to smoothly move the chuck ring 4 in the axial direction inside the ring arrangement recess 24. In this embodiment, the protrusion 43 is formed so as to be biased toward the front side in the insertion direction of the chuck ring 4. As shown in FIG. 1, in the initial state, the protrusion 43 is in contact with a step (chamfered portion 244) between the back circumferential surface 242 and the front circumferential surface 243 of the ring arrangement recess 24. Thereby, when no pulling load is applied to the metal tube P, the protrusion 43 is located adjacent to the step, so the chuck ring 4 can be stably arranged.

The spacer 5 is a solid annular body, as shown in FIG. The spacer 5 can be made of metal or non-metal (resin, ceramics, etc.). The spacer 5 makes surface contact with the main body portion 31 of the lock ring 3. The spacer 5 also makes surface contact with the main body portion 41 of the chuck ring 4. The lock ring 3 is a plate-shaped body, but due to the presence of the solid spacer 5, when the metal tube P is displaced from the cylindrical body 2, the displacement is caused by the lock ring 3 and the spacer 5. It is reliably transmitted to the chuck ring 4 via.

The spacer 5 includes a main body portion 51 that revolves around the axis of the cylindrical body portion 2 and a protrusion portion 52 that overlaps the first claw portion 32 at a radially inner position of the lock ring 3. The radially outer surface of the protruding portion 52 contacts the first claw portion 32 of the lock ring 3 adjacent to the rear side in the insertion direction. When the metal tube P is displaced from the cylindrical body portion 2, the first claw portion 32 is deformed to face in the opposite direction to the tube insertion direction due to the overlapping of the protrusions 52. It is possible to prevent the metal pipe P from being caught in the state of being lost.

A plurality of O-rings 6 (three in this embodiment) serving as leak-proof rings are provided on the front side of the ring arrangement recess 24 in the tube insertion direction. A groove into which the O-ring 6 is fitted is formed on the inner surface of the cylindrical body part 2 (specifically, the lid part 22). Note that the outer periphery of the metal tube P is damaged by the lock ring 3 biting, but since that part is further back than the O-ring 6 in the tube insertion direction, the outer periphery of the metal tube P in contact with the O-ring 6 is free from scratches. This curved surface does not affect the leak prevention function of the O-ring 6.

Next, a description will be given of what happens when the metal tube P is displaced so as to come out of the cylindrical body portion 2. At this time, the lock ring 3 located on the back side in the insertion direction receives the displacement of the metal tube P and moves away from the back side vertical surface 241, and the other lock ring 3 and the two spacers 5 , and press the chuck ring 4 toward the front in the tube insertion direction. Note that until each lock ring 3 is entirely moved, only the first claw portion 32 is deformed so as to curve toward the front side in the tube insertion direction. On the other hand, in the chuck ring 4, immediately after insertion, the second claw part 42 is in contact with the outer peripheral surface of the metal tube P without biting (see FIG. 1), and the main body part 41 protrudes under the pressure of the lock ring 3. The diameter of the portion 43 is reduced by being pressed against the front circumferential surface 243, and the second claw portion 42 bites into the outer circumferential portion of the metal tube P as the diameter is reduced (see FIG. 2). In other words, the pressing force by the lock ring 3 via the spacer 5 moves the main body 41 toward the front side in the tube insertion direction inside the chuck ring 4, crosses the step (chamfered part 244), The force is transmitted radially inwardly to the second claw part 42 by the protrusion 43 that abuts on the projection 243 . In this way, the force of the metal tube P trying to come out of the cylindrical body part 2 causes the diameter of the chuck ring 4 to be reduced by the front side circumferential surface 243 and the protrusion part 43, and is biased in the radial direction by the diameter reduction. The second claw portion 42 bites into the outer peripheral portion of the metal tube P. For this reason, the lock ring 3 can supplement the prevention by the chuck ring 4 by biting. Therefore, the lock ring 3 and chuck ring 4 are combined (in this embodiment, the spacer 5 is also combined) to prevent the refrigerant piping from coming off at a higher working pressure than other gas piping or water piping. However, it is possible to securely prevent it from coming off.

Although the embodiments of the present invention have been described above with reference to several examples, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention. Can be done.

For example, the retaining mechanism 11 of the embodiment described above has a symmetrical shape in the axial direction. However, the shape is not limited to this, and the shape may be asymmetrical in the axial direction. For example, the same configuration as one side or the other side in the axial direction may be provided only on one side in the axial direction, and the other side may be configured to make a screw connection to the metal pipe P. In this case, a cap nut provided at the flared end of the metal tube P, for example, is screwed into the threaded portion.

Further, in the embodiment described above, the inner circumferential surface (back side circumferential surface 242, near side circumferential surface 243) provided in the ring arrangement recess 24 was a surface parallel to the axial direction. However, the present invention is not limited thereto, and may be a surface inclined with respect to the axial direction (for example, a slope whose diameter decreases toward the front side in the tube insertion direction). In this case, the back side circumferential surface 242 and the near side circumferential surface 243 may be configured as one continuous surface. Moreover, if the inner circumferential surface is an inclined surface, the diameter of the chuck ring 4 is sequentially reduced according to the axial center position where the chuck ring 4 exists. Furthermore, in the embodiment described above, the protrusion 43 is formed as a pressing portion of the chuck ring 4. However, the present invention is not limited to this, and the slope may correspond to the slope of the ring arrangement recess 24.

1 Metal pipe joint 11 Retention mechanism 2 Cylindrical body part 21 Main body part (cylindrical body part)
22 Lid 23 O-ring 24 Ring placement recess 241 Back vertical surface 242 First surface, back circumferential surface 243 Second surface, front circumferential surface 3 Lock ring 31 Main body (lock ring)
32 First claw part 4 Chuck ring 41 Main body part (chuck ring)
42 Second claw portion 422 Surface including a component along the tube insertion direction, end surface (second claw portion)
43 Pressing part, projection part 5 Spacer 51 Main body part (spacer)
52 Projection 6 Leakproof ring (O-ring)

Claims (4)

a cylindrical body portion that receives the inserted metal tube;
a lock ring disposed inside the cylindrical body portion;
a chuck ring disposed inside the cylindrical body portion and closer to the front side than the lock ring in the tube insertion direction;
a leak-prevention ring that is disposed inside the cylindrical body portion and on the front side in the tube insertion direction than the lock ring and the chuck ring, and that comes into contact with the outer circumferential surface of the metal tube in the inserted state;
The inner periphery of the cylindrical body portion is provided with a ring arrangement recess into which the lock ring and the chuck ring are fitted,
The ring arrangement recess has a first surface on the inner periphery on the back side in the tube insertion direction that comes into contact with the lock ring immediately after the tube is inserted, and has a diameter smaller than the first surface on the inner periphery on the front side in the tube insertion direction. Equipped with a second side that was
The lock ring includes a first claw portion that faces the tube insertion direction and bites into the outer peripheral portion of the metal tube immediately after insertion,
The chuck ring is capable of reducing its diameter with respect to the axis of the cylindrical body portion, and includes a pressing portion that can abut on the inner periphery of the ring arrangement recess at a radially outer position, and a pressure portion that protrudes in a radially inward direction. Equipped with two claws,
The lock ring presses the chuck ring toward the front side in the tube insertion direction when the metal tube is displaced from the cylindrical body portion,
The chuck ring is in contact with the first surface immediately after insertion, and the second claw part is in contact with the outer peripheral surface of the metal tube without biting, and the tube is inserted under pressure from the lock ring. A metal pipe joint that moves toward the front in a direction and contracts in diameter by abutting the pressing part against the second surface, and as the diameter contracts, the second claw part bites into an outer peripheral part of the metal pipe. The metal pipe joint according to claim 1, wherein in the chuck ring, the second claw portion is provided at a position overlapping the pressing portion in the tube insertion direction. The chuck ring includes a main body that revolves around the axis of the cylindrical body, and the second claw extends radially inward from the main body,
The metal pipe joint according to claim 1 or 2, wherein the second claw portion has a surface including a component along the pipe insertion direction. The metal pipe joint according to claim 1 or 2, wherein a spacer is provided between the lock ring and the chuck ring and comes into contact with both.