JP2023161212A - Pipe joint - Google Patents

Abstract

To provide a pipe joint which prevents leakage of fluid flowing therein.SOLUTION: A pipe joint 1 includes a joint body 10 and a nut 20. The nut 20, which is attached around a refrigerant pipe P at a rear part relative to an expansion part Pa, is coupled to the joint body 10 into which the refrigerant pipe P, which has the expansion part Pa at its tip, is inserted. Further, the expansion part Pa is engaged with the nut 20 and the refrigerant pipe P is connected to the joint body 10 in a state that removal of the refrigerant pipe P is prevented. The nut 20 is formed with: a small diameter hole part 21 into which the expansion part Pa cannot be inserted; and a large diameter hole part 22 into which the expansion part Pa can be inserted. The large diameter hole part 22 is formed with a female screw, and a step surface 23 is formed between the large diameter hole part 22 and the small diameter hole part 21. When the nut 20 is threadedly engaged with a male screw of the joint body 10, a housing space 26 of the expansion part Pa is formed between the step surface 23 and one end of the joint body 10 at the large diameter hole part 22. The joint body 10 is provided with a butted part 13 with which the nut 20 is butted when the nut 20 is screwed into the joint body 10 to cause the housing space 26 to be formed having a predetermined space.SELECTED DRAWING: Figure 3

Description

The present invention relates to a pipe joint for connecting pipe bodies.

Connections between pipe bodies through which fluid flows are performed by brazing, welding, mechanical joints, and the like. Brazing and welding operations require a great deal of effort and skill, and there is a risk of fire since they use fire. Therefore, there is a growing demand for mechanical joints that can be easily connected without using fire.

Patent Document 1 listed below describes a pipe joint having a mechanical connection structure. This pipe joint consists of a tubular joint body (joint body) into which a steel pipe (pipe) is inserted through an opening at one end, and a connecting nut that is wrapped around the steel pipe and connected to one end of the intermediate joint body by screwing. (nut). A connecting nut ringed around the steel pipe behind the protrusion is connected to the intermediate joint body into which a steel pipe with a protrusion (bulge) is inserted near the tip, and the protrusion of the steel pipe is locked to the connecting nut. The steel pipes are connected in a way that prevents them from coming off.

A male thread is formed on the outer peripheral surface of one end of the intermediate joint body. The inside of the connection nut is formed with a small-diameter hole through which the protrusion of the steel pipe cannot be inserted, and a large-diameter hole adjacent to the small-diameter hole on the side of the intermediate joint body through which the protrusion can be inserted. This large diameter hole has a female thread that can be screwed into the male thread of the intermediate joint body. A stepped surface is formed between the large diameter hole and the small diameter hole. When the connecting nut is screwed into the intermediate joint body, a housing space for the protrusion of the steel pipe is formed in the large diameter hole between the stepped surface and one end of the joint body.

JP2002-257272A (0010, Figure 6)

In the pipe joint of Patent Document 1, the spacing between the housing spaces of the protrusions can be adjusted by screwing in and unscrewing the connection nut, but it was not possible to confirm that the spacing was a predetermined spacing. As a result, the protrusion of the steel pipe may be damaged if the connection nut is screwed in too much, or the steel pipe may be connected without being screwed in enough. As a result, the steel pipes sometimes loosened and fluid inside the pipe joints leaked.

Further, if the protrusion of the steel pipe is strongly held between the connecting nut and the intermediate joint body, the steel pipe cannot be turned in the circumferential direction, and the direction of the curved steel pipe cannot be changed.
Further, when water is generated in the accommodation space due to condensation or the like, the water remains in the accommodation space and the water freezes and expands repeatedly, which may cause damage to the pipe joint.

The present invention has been made to solve at least one of the above problems, and a pipe joint according to one aspect of the present invention includes a joint body having a tubular shape into which a pipe is inserted through an opening at one end, and a pipe joint body having a tubular shape and into which a pipe is inserted through an opening at one end. and a nut that is wrapped around the joint body and is threadedly connected to one end of the joint body.
The nut, which is encircled around the pipe behind the bulge, is coupled to the joint body into which a pipe having a bulge near the tip is inserted. By locking the bulging portion of the pipe with the nut, the pipe is connected in a manner that prevents it from coming off.
A male thread is formed on the outer peripheral surface of one end of the joint body.
Inside the nut, there is formed a small-diameter hole through which the bulge of the pipe cannot be inserted, and a large-diameter hole adjacent to the small-diameter hole on the side of the joint body through which the bulge can be inserted. has been done. A female thread that can be screwed into the male thread of the joint body is formed in this large diameter hole, and a stepped surface is formed between the large diameter hole and the small diameter hole.
When the nut is screwed onto the joint body, a housing space for the bulge of the pipe is formed in the large diameter hole between the stepped surface and one end of the joint body.
The joint body is provided with an abutting portion against which the nut abuts when the accommodation space reaches a predetermined interval by screwing the nut.

According to the above configuration, when the nut screwed into the joint body abuts against the abutting portion, a housing space with a predetermined interval is formed. Therefore, it is possible to prevent damage to the bulging portion of the pipe due to over-screwing of the nut, or to prevent the pipe from being connected in a loose state due to insufficient screw-in. As a result, it is possible to prevent leakage of fluid from within the pipe joint due to damage to the bulge or loose connection of the pipe.

Preferably, the intervals between the housing spaces are set such that the bulging portion of the pipe can move in the circumferential direction within the housing space.
According to the above configuration, since the pipe can be rotated in the circumferential direction, when the pipe has a curved shape, the direction of the pipe can be freely changed.

Preferably, the nut has a peripheral wall formed with a through hole that communicates the housing space with the outside.
According to the above configuration, water generated in the housing space due to dew condensation or the like can be discharged. Therefore, it is possible to prevent the pipe joint from being damaged due to repeated freezing and expansion of water within the housing space.

According to the present invention, it is possible to provide a pipe joint that prevents leakage of fluid flowing inside.

FIG. 1 is an exploded perspective view of a pipe joint according to an embodiment of the present invention. (A) It is a sectional view of the main part showing the same pipe joint disassembled into a nut and a joint body. (B) It is a sectional view of the main part of the pipe joint. FIG. 3 is a cross-sectional view of a main part showing the process of connecting the pipe joint and a pipe, in which (A) shows a state in which a nut is attached to the pipe behind the bulging part of the pipe, and (B) shows a state in which a nut is attached to the pipe behind the bulging part of the pipe. The end portion is shown inserted into the joint body, and (C) shows the state in which the connection is completed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A pipe joint that constitutes one embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In this embodiment, the present invention is applied to a pipe joint for connecting a refrigerant pipe that connects an indoor unit and an outdoor unit of an air conditioner.

As shown in FIG. 1, a pipe joint 1 to which a refrigerant pipe P (pipe) is connected includes a joint body 10 and a nut 20.
The refrigerant pipe P is made of metal (made of aluminum alloy in this embodiment) and has a curved shape. The refrigerant pipe P may be a straight pipe. The refrigerant pipe P has a bulge Pa that is formed by beading and protrudes radially outward near the end on the side connected to the pipe joint 1. As shown in FIG. 2(A), the cross-sectional shape of the outer surface of the bulging portion Pa is arcuate.

The joint body 10 is made of metal, and in this embodiment is made of the same aluminum alloy as the refrigerant pipe P, and is formed into a trident-shaped tube shape. The joint body 10 has a main pipe part 11 and a branch pipe part 12 branching from the main pipe part 11. A passage hole 10a communicates the inside of the main pipe section 11 and the branch pipe section 12.

An opening 12a into which the refrigerant pipe P is inserted is formed at the tip of the branch pipe section 12. The inner diameter of the opening 12a is smaller than the outer diameter of the bulging part Pa of the refrigerant pipe P, and when the distal end of the refrigerant pipe P is inserted into the opening 12a, the bulging part Pa touches the distal end surface of the branch pipe part 12. It will come into contact with.

A male thread 12b for screwing the nut 20 is formed on the outer circumferential surface of the distal end of the branch pipe portion 12. An abutment portion 13 is provided on the outer circumferential surface of the inner side of the male screw 12b, with which the tip of the screwed nut 20 abuts. The abutment portion 13 protrudes radially outward from the branch pipe portion 12, extends in an annular shape, and has an abutment surface 13a facing the nut 20 side.

A sealing material mounting groove 12c that extends annularly is formed on the inner peripheral surface of the passage hole 10a on the far side from the opening 12a. An O-ring 30, which is a sealing member, is mounted in the sealing material mounting groove 12c.

The O-ring 30 is formed in an annular shape from an elastic material such as rubber, has a circular cross section, and can elastically expand and contract in diameter. The outer diameter of the O-ring 30 is slightly larger than the inner diameter of the sealing material mounting groove 12c, and the inner diameter of the O-ring 30 is slightly smaller than the outer diameter of the refrigerant pipe P. The O-ring 30 presses into contact with the outer peripheral surface of the refrigerant pipe P inserted into the passage hole 10a from the opening 12a, and seals between the outer peripheral surface of the refrigerant pipe P and the inner peripheral surface of the passage hole 10a. In this sealed state, the refrigerant pipe P can be rotated in its circumferential direction.

The nut 20 is made of aluminum alloy and is coupled to the tip of the branch pipe section 12 by screwing. Inside the nut 20, there is a small diameter hole 21 through which the bulge Pa of the refrigerant pipe P cannot be inserted, and a large diameter hole adjacent to the branch pipe 12 side with respect to the small diameter hole 21 through which the bulge Pa can be inserted. A portion 22 is formed.

The large diameter hole 22 is formed with a female thread 22a that can be screwed into the male thread 12b of the branch pipe part 12. A stepped surface 23 facing in the axial direction of the nut 20 is formed between the large diameter hole 22 and the small diameter hole 21. A through-hole 24 is formed in the peripheral wall of the nut 20 on the side closer to the branch pipe portion 12 than the step surface 23 to communicate the inside and outside.

A tool hook 25 is formed on the outer peripheral surface of the nut 20 on the side opposite to the branch pipe section 12 to hang a tool such as a spanner. The tool hanging portion 25 is formed by a pair of parallel flat surfaces.

As shown in FIG. 2(B), when the nut 20 is screwed onto the branch pipe section 12, the large diameter hole section 22 has a refrigerant tube between the stepped surface 23 and the tip of the branch pipe section 12. An accommodation space 26 for accommodating the bulge part Pa of P is formed. When the nut 20 is screwed in and the accommodation space 26 reaches a predetermined interval suitable for accommodating the protruding portion Pa, the nut 20 comes into contact with the contact surface 13a of the abutting portion 13 of the branch pipe portion 12. It has become.

At this time, the through hole 24 communicates the housing space 26 with the outside. Thereby, even if water is generated in the housing space 26 due to dew condensation or the like when the refrigerant pipe P is connected, it can be discharged. Therefore, it is possible to prevent the pipe fitting 1 from being damaged due to repeated freezing and expansion of water accumulated in the accommodation space 26.

The process of connecting the refrigerant pipe P to the pipe joint 1 having the above configuration will be explained with reference to FIG. 3.
As shown in FIG. 3(A), a nut 20 is fitted around the refrigerant pipe P behind the bulging part Pa, with the side connected to the pipe joint 1 being the tip of the refrigerant pipe P.
Next, as shown in FIG. 3(B), the refrigerant pipe P is inserted into the passage hole 10a from the opening 12a and passed through the O-ring 30, and the bulging part Pa is brought into contact with the distal end surface of the branch pipe part 12. let Subsequently, the nut 20 is screwed and coupled to the branch pipe section 12 to form an accommodation space 26, and the bulge Pa is accommodated between the stepped surface 23 and the tip of the branch pipe section 12.

As shown in FIG. 3(C), the nut 20 is screwed in and brought into contact with the contact surface 13a of the abutting portion 13. At this time, the bulging part Pa is accommodated in the housing space 26 with appropriate spacing to prevent the bulging part Pa from being damaged or the refrigerant pipe P to be connected in a loose state. In this embodiment, within the housing space 26, the bulging portion Pa contacts the step surface 23 and the tip of the branch pipe portion 12, is slightly crushed in the axial direction of the refrigerant pipe P, and is slightly crushed in the circumferential direction of the refrigerant pipe P. It is now impossible to move it. The bulging portion Pa is locked by the nut 20, and thereby the refrigerant pipe P is connected to the pipe joint 1 in a manner that prevents it from coming off.

According to the embodiment described above, when the nut 20 screwed into the branch pipe portion 12 abuts against the abutment portion 13, accommodation spaces 26 with a predetermined interval suitable for accommodating the bulge portion Pa are formed. Therefore, damage to the bulging portion Pa due to over-screwing of the nut 20 and connection of the refrigerant pipe P in a loose state due to insufficient screwing can be prevented. Furthermore, it is possible to prevent leakage of refrigerant from the pipe joint 1 caused by damage to the bulging portion Pa or a loose connection of the refrigerant pipe P.

Note that the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the gist thereof.
The spacing between the accommodation spaces 26 may be such that the bulging portion Pa abuts against the step surface 23 and the distal end portion of the branch pipe portion 12 to such an extent that it does not collapse.
The spacing between the housing spaces 26 may be such that the bulging portion Pa that contacts the step surface 23 and the tip of the branch pipe portion 12 can move in the circumferential direction of the refrigerant pipe P. Thereby, the refrigerant pipe P can be turned in the circumferential direction with respect to the pipe joint 1, and if the refrigerant pipe P has a curved shape, its direction can be changed freely.
In the above embodiment, the refrigerant pipe P was connected to the end of the branch pipe section 12, but it may be connected to the end of the main pipe section 11.
In the embodiment described above, the shape of the pipe joint is a three-pronged shape having one branch, but it may be a shape without a branch, or a cross tube shape having two branches.
The pipe connected to the pipe joint is not limited to a refrigerant pipe, but may be a pipe through which other fluid flows.
The metal used for the pipe joint and pipe is not limited to aluminum alloy, but may also be copper, brass, stainless steel, iron, or the like.

The present invention can be applied to a pipe joint for connecting pipe bodies.

P Refrigerant pipe (pipe)
Pa Swelling part 1 Pipe joint 10 Joint body 10a Passage hole 11 Main pipe part 12 Branch pipe part 12a Opening 12b Male thread 12c Seal material mounting groove part 13 Abutting part 13a Contact surface 20 Nut 21 Small diameter hole part 22 Large diameter hole part 23 Step Surface 24 Through hole 25 Tool hanging portion 26 Accommodation space 30 O-ring

Claims (3)

A pipe having a tubular shape and having a bulge near its tip, comprising a joint body into which a pipe is inserted through an opening at one end, and a nut that is encircled around the pipe and connected to one end of the joint body by screwing. The inserted joint body is coupled with the nut that is attached to the pipe behind the bulge, and the bulge of the pipe is locked to the nut, so that the pipe is prevented from coming off. A pipe joint connected with
The above-mentioned joint body has a male thread formed on the outer peripheral surface of one end thereof,
Inside the nut, there is a small-diameter hole through which the bulge of the pipe cannot be inserted, and a large-diameter hole adjacent to the small-diameter hole on the side of the joint body through which the bulge can be inserted. a female thread that can be screwed into the male thread of the joint body is formed in the large diameter hole, and a step surface is formed between the large diameter hole and the small diameter hole,
When the nut is screwed onto the joint body, a housing space for the bulge of the pipe is formed in the large diameter hole between the stepped surface and one end of the joint body;
The pipe joint is characterized in that the joint main body is provided with an abutting portion against which the nut abuts when the accommodation space reaches a predetermined interval by screwing the nut. 2. The pipe joint according to claim 1, wherein the spacing between the housing spaces is set such that the bulging portion of the pipe can move in the circumferential direction within the housing space. 3. The pipe joint according to claim 1, wherein a through hole is formed in the peripheral wall of the nut to communicate the accommodation space with the outside.

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