JP5442348B2 - Flexible pipe joint structure - Google Patents

Description

  The present invention relates to a joint structure of a flexible pipe that connects, for example, a gas pipe and a gas appliance.

  A flexible pipe is used when connecting a gas pipe to a gas appliance used in a kitchen or the like. Since this flexible pipe has a bellows-like tube wall and can be bent manually into a free shape, the installation space can be reduced and piping work can be facilitated. And the joint member for connecting this to a gas appliance or a gas pipe is provided in the both ends of this flexible pipe.

As the joint structure, there is a conventional structure shown in Patent Document 1 or Patent Document 2, for example. The joint structures described in these patent documents employ a so-called metal touch seal structure as a connection structure between the flexible pipe and the joint member. That is, the tip of the flexible pipe is expanded in a tapered shape, and the tip of the joint pipe (nipple) is inserted inside the taper. The cap nut is inserted into the joint pipe from the outside of the taper of the flexible pipe. The tapered portion of the flexible pipe is sandwiched between the tapered surface of the outer peripheral surface of the joint pipe and the tapered surface of the inner peripheral surface of the cap nut so that the space between them is sealed. It has become.
In this case, in the joint structure shown in Patent Document 1, a seal packing is provided between the joint pipe and the cap nut so that the tip of the taper portion of the flexible pipe abuts, and the seal is also sealed by this seal packing. It has become. Moreover, in the joint structure shown by patent document 2, when the taper part of a flexible pipe is folded in two, it forms thicker than another part, and this half-folded part is a joint pipe (nipple) and a cap nut. And is firmly sandwiched between the two.

Japanese Patent No. 4156218 JP 2005-133918 A

  By the way, when such a flexible pipe is connected to a gas appliance in a kitchen or the like, piping work may be performed with the joint pipe removed from the flexible pipe in order to penetrate the floor or wall. At that time, when the joint pipe is handled alone, it may be accidentally dropped and hit against the floor or wall to cause damage such as scratches. In that case, if the tapered surface of the outer peripheral surface of the joint pipe is damaged, the outer peripheral surface of the distal end is a portion that becomes a seal surface of the metal touch, and the sealing performance is impaired.

  The present invention has been made in view of the above-described circumstances, and adopts a so-called metal touch seal structure, and can protect the seal surface even if it hits a wall or a floor due to a drop or the like. It aims at providing the joint structure which can be performed.

The joint structure of the flexible pipe of the present invention includes a flexible pipe made of a metal pipe having a tapered portion whose diameter is expanded at a tip portion, a joint pipe having an inner seal surface abutting against the inner surface of the tapered portion of the flexible pipe, A cap nut having an outer seal surface that abuts the outer surface of the tapered portion of the flexible tube by screwing into the joint tube and sandwiches the tapered portion with the inner seal surface of the joint tube; and A cylindrical protrusion extending in the axial direction from the tip of the inner seal surface is formed at the tip of the joint tube, and the taper angle of the inner seal surface is smaller than the taper angle of the outer seal surface. It is formed .

In the case of this joint structure, even if the joint pipe is dropped when handled alone, the cylindrical protrusion extends in the axial direction from the tip of the inner seal surface. The tip portion collides with the floor or wall, thereby preventing the inner seal surface from colliding with the floor or wall.
In addition, the tubular projecting portion of the joint pipe is inserted into the flexible pipe in the assembled state, and can be reinforced by supporting the flexible pipe from the inside, and when the flexible pipe is bent, etc. Even if an external force acts on the metal touch seal, the external force can be supported by the cylindrical protruding portion to limit the action of the external force on the metal touch seal portion, and the sealing performance can be reliably maintained.

In the joint structure of the present invention, it is preferable that the outer peripheral surface of the distal end portion of the cylindrical projecting portion is formed as a tapered surface that gradually decreases in diameter toward the tip.
When inserting a joint pipe into a flexible pipe, both can be centered by the taper surface of a cylindrical protrusion, and field work can be facilitated.

In the joint structure of the present invention, the inner sealing surface of the cap nut may be formed with an arc surface that is convex inward in the radial direction.
The arc surface comes into contact with the outer surface of the taper portion of the flexible tube, and when the cap nut is fastened to the joint tube, the arc surface slides while pressing the taper portion of the flexible tube, and the sliding becomes smooth. Thus, the occurrence of bias or the like is prevented, and a metal touch structure can be reliably obtained.

  In the joint structure of the present invention, a sealing material may be applied to both sides of the tapered portion of the flexible pipe. In addition to the metal touch seal structure, it can be reliably sealed with a sealing material.

  According to the joint structure of the flexible pipe of the present invention, since the cylindrical projection extending from the tip of the inner seal surface is formed at the tip of the joint pipe, the joint pipe may be dropped when handled alone. However, the inner seal surface is prevented from being damaged and does not hinder the soundness of the metal touch seal structure.

It is sectional drawing which abbreviate | omitted one part which shows the flexible tube of one Embodiment of this invention, and the joint member of the both ends. It is an expanded sectional view of the joint structure part of FIG. It is sectional drawing which shows the example of the contact attitude | position with respect to a floor surface at the time of dropping the joint pipe of FIG. 1 on a floor surface independently. It is an expanded sectional view similar to FIG. 2 which shows other embodiment of this invention.

Hereinafter, embodiments of the joint structure of a flexible pipe of the present invention will be described with reference to the drawings.
FIG. 1 shows a flexible tube 1 according to this embodiment and joint members 2 and 3 provided at both ends thereof. The flexible tube 1 is formed by processing a metal tube made of copper, copper alloy, stainless steel, or the like into a bellows shape, and cylindrical portions 5 having no bellows are formed at both ends of the bellows tube portion 4. A tapered portion 6 that gradually increases in diameter toward the distal end is formed at the distal end of the cylindrical portion 5. In addition, the unevenness | corrugation which makes the bellows tube part 4 may be an annular thing mutually independent, and a spiral thing may be sufficient. Moreover, it does not necessarily need to be a bellows shape, and it only needs to be a flexible tube.

  The joint members 2 and 3 are composed of joint pipes 7 and 8 connected to a gas pipe or a gas appliance, and a cap nut 9 for fixing the flexible pipe 1 to the joint pipes 7 and 8 in a connected state. . The joint pipes 7 and 8 are classified into a female thread connection type and a male thread connection type according to the counterpart to be connected. FIG. 1 shows the joint pipe 7 of the female thread connection type at one end of the flexible pipe 1 and the other. The threaded connection type joint pipe 8 is provided at the end of the pipe, but depending on the use situation of the gas appliance, etc., both ends have a female thread connection type joint pipe 7 and both ends have a male thread connection type joint pipe. A combination of 8 may be used.

  In the case of the female thread connection type joint pipe 7, the joint pipes 7 and 8 are formed such that the female thread connection portion 11 and the tubular portion 12 are coaxially connected to each other, and the length of the outer peripheral portion of the tubular portion 12 is long. A threaded portion 13 is formed at an intermediate position in the vertical direction, and the tapered inner seal surface is formed by gradually reducing the diameter of the outer peripheral surface toward the distal direction from the male threaded portion 13 in the cylindrical portion 12. 14 is formed. Further, a cylindrical protrusion 15 extending in the axial direction from the tip of the inner seal surface 14 is integrally formed at the tip of the inner seal surface 14. The cylindrical projecting portion 15 has an outer diameter that is slightly smaller than the inner diameter of the cylindrical portion 5 at both ends of the flexible tube 1. The distal end portion of the cylindrical projecting portion 15 has its outer peripheral surface in the distal direction. The taper surface 16 is chamfered so as to be gradually reduced in diameter.

In this case, the outer diameter of the cylindrical protrusion 15 is smaller by 0.5 to 2 mm than the inner diameter of the cylindrical portion 5 of the flexible tube 1. The length L of the cylindrical protrusion 15 is 2 to 5 mm, for example, and the angle θ1 of the tapered surface 16 at the tip is 30 to 60 °. Moreover, this cylindrical protrusion part 15 may incline so that the diameter may reduce slightly as the whole goes to a front-end | tip, and the front-end | tip may taper off.
The outer peripheral surface of the female thread connecting portion 11 of the joint pipe 7 is formed in a hexagonal cross section so that it can be rotated by engaging a tool such as a spanner.

  On the other hand, in the male thread connection type joint pipe 8, a cylindrical part 12 similar to the female thread connection type joint pipe 7 is formed on the male thread connection part 17 in a coaxially connected state. Since the shape of the cylindrical portion 12 is the same as that of the joint pipe 7 of the female screw connection type, description thereof is omitted. The male screw connection portion 17 is formed by integrally forming a tool engaging portion 19 having a hexagonal cross section at the base end portion of the male screw portion 18 and can be rotated by engaging a tool such as a spanner. Yes.

  The cap nut 9 has a female thread portion 21 formed on the inner peripheral portion of one end portion thereof, and the other end portion is an inwardly bent portion 22 that is bent inward in the radial direction. A tapered outer seal surface 23 is formed on the inner peripheral surface of 22 and gradually decreases in diameter toward the tip. The distal end portion of the outer seal surface 23 is formed on an arc surface 23 a having a radius R that is convex inward, and the distal end portion that is the minimum diameter of the arc surface 23 a is smaller than the outer diameter of the cylindrical portion 5 of the flexible tube 1. It has a slightly larger inner diameter. The radius of curvature R of the arc surface 23a is 0.5 to 2 mm. Further, the outer peripheral surface of the female thread portion 21 of the cap nut 9 is formed in a hexagonal cross section, and can be rotated by engaging a tool such as a spanner.

And the taper part 6 of the flexible pipe 1 is interposed between the inner seal surface 14 of the joint pipes 7 and 8 and the outer seal surface 23 of the cap nut 9, and is held between the seal surfaces 14 and 23. It is supposed to be fixed. In this case, as shown in FIG. 2, the taper angle θ2 of the inner seal surface 14 and the taper angle θ3 of the outer seal surface 23 are set to slightly different angles, and the taper angle θ2 of the inner seal surface 14 is more outward. The seal surface 23 is formed smaller than the taper angle θ3. For this reason, the inner seal surface 14 of the joint pipes 7 and 8 is in line contact with the bent surface 24 from the cylindrical portion 5 to the tapered portion 6 on the inner peripheral surface of the tapered portion 6 with respect to the flexible tube 1. On the outer peripheral surface of the tapered portion 6, the arc surface 23 a of the outer seal surface 23 of the cap nut 9 comes into line contact, and when the cap nut 9 is tightened to the joint pipes 7 and 8, It is designed to concentrate force, so that sufficient airtightness can be obtained with a small tightening force.
Specifically, the taper angle θ2 of the inner seal surface 14 is 30 to 45 °, and the taper angle θ3 of the outer seal surface 23 is 40 to 65 °. Further, the taper portion 6 of the flexible tube 1 has a thickness of 0.5 to 1 mm and an angle θ4 of 35 to 55 °, and between each of the metal touch seal surfaces 14 and 23, θ2 < It is set to have a relationship of θ4 <θ3.

  In the joint structure of the flexible pipe constructed as described above, when this is attached to a gas appliance such as a kitchen, the joint pipes 7 and 8 of the joint members 2 and 3 are removed from the flexible pipe 1 and handled by mistake. The case where it is dropped will be described. In particular, when the vicinity of the inner seal surface 14 of the joint pipes 7 and 8 falls in a posture that collides with the floor surface, it is necessary to protect the inner seal surface 14 from being scratched. 8 is formed with a cylindrical projecting portion 15 extending in the axial direction from the tip of the inner seal surface 14 as shown in FIG. 3 (FIG. 3 shows a female pipe connection type joint pipe 7. The tip of the cylindrical protrusion 15 and the end that is the maximum outer diameter of the inner seal surface 14 come into contact with the floor surface F. For this reason, the taper surface of the inner seal surface 14 disposed between the tip end (point A) of the cylindrical protrusion 15 and the maximum outer diameter end portion (point B) of the inner seal surface 14 is in contact with the floor surface F. In other words, it is possible to reliably prevent the occurrence of damage such as the inner seal surface 14 which is important as a metal touch seal structure being damaged at the time of impact.

When the removed joint pipes 7 and 8 are inserted into the flexible pipe again, first, the distal cylindrical protrusion 15 is inserted into the cylindrical part 5 of the flexible pipe 1. At this time, since the tapered surface 16 is formed at the tip of the cylindrical protruding portion 15, the flexible tube 1 comes into contact with the tapered surface 16, and the cylindrical protruding portion 15 and the flexible tube 1 are connected to each other. Since they are aligned, the insertion into the flexible tube 1 is facilitated, and the occurrence of problems such as tilting is avoided. Therefore, the inner seal surface 14 of the joint pipes 7 and 8 and the outer seal surface 23 of the cap nut 9 are in contact with each other in a state where the taper portion 6 is accurately aligned, and a metal touch seal structure can be reliably formed.
Moreover, since the arc surface 23a formed in the front-end | tip part of the outer side seal surface 23 of the cap nut 9 contact | abuts to the outer peripheral surface of the taper part 6 of the flexible pipe 1, the vertex of the arc surface 23a will line-contact. The sliding with the taper part 6 at the time of the operation | work which fastens the cap nut 9 can be made smooth, and a reliable metal touch seal structure can be constructed | assembled.

  And in the state which assembled these joint members 2 and 3 and the flexible pipe 1, the cylindrical protrusion part 15 of the joint pipes 7 and 8 is made into the insertion state inside the cylindrical part 5 of the flexible pipe 1, The cylindrical part 5 The bent portion 24 of the tapered portion 6 whose diameter is expanded from the abutting portion contacts the inner seal surface 14 of the joint pipes 7 and 8, and the arc surface 23 a of the outer seal surface 23 of the cap nut 9 contacts the outer surface of the tapered portion 6. The taper portion 6 is tightened between the seal surfaces 14 and 23. In this fastened state, the cylindrical protrusions 15 of the joint pipes 7 and 8 are inserted into the cylindrical part 5 of the flexible pipe 1, so that an external force such as bending the bellows pipe part 4 of the flexible pipe 1 acts. Even in such a case, since the cylindrical projecting portion 15 of the joint pipes 7 and 8 is supported from the inside in the cylindrical portion 5, external force is less likely to be applied from the cylindrical portion 5 to the tapered portion 6, and the metal touch seal structure is ensured. Can be maintained.

  In such a metal touch seal structure, as shown in another embodiment of FIG. 4, a sealing material 31 may be applied to both surfaces of the tapered portion 6 of the flexible tube 1. As the sealing material 31, a liquid sealing material made of acrylic resin, silicone resin, or the like is used. In this case, a groove 32 may be formed along the circumferential direction on the outer peripheral surface of the cylindrical projecting portion 15 of the joint pipe 7.8, and the sealing material 31 may be accumulated in the groove 32. The sealing material 31 can be reliably interposed between the flexible pipe 1 and the sealing material 31 by storing the sealing material 31 on the flexible pipe 1.

Although the embodiment of the present invention has been described above, the present invention is not limited to this description and can be appropriately changed without departing from the technical idea of the present invention.
For example, the tapered surface 16 at the tip of the cylindrical projecting portion 15 is chamfered in a planar shape, but may be a circular arc-shaped tapered surface that protrudes outward. Further, the inner seal surface 14 that contacts the inner peripheral surface of the tapered portion 6 of the flexible tube 1 is also shown as a straight tapered surface (conical surface), but it is formed in an arc surface that is slightly convex outward. May be.
Further, in another embodiment shown in FIG. 4, the groove 32 is not located in the cylindrical protruding portion 15 but on the inner side as long as it avoids the position where the bent portion 24 of the tapered portion 6 of the flexible tube 1 abuts. The seal surface 14 may be formed.

DESCRIPTION OF SYMBOLS 1 Flexible pipe 2, 3 Joint member 4 Bellows pipe part 5 Cylindrical part 6 Tapered part 7,8 Joint pipe 9 Cap nut 14 Inner seal surface 15 Cylindrical protrusion 16 Tapered surface 22 Inward bending part 23 Outer seal surface 23a Arc surface 24 Bent part 31 Sealing material 32 Groove

Claims (4)

A flexible tube made of a metal tube having a tapered portion whose diameter is expanded at the tip, a joint tube having an inner seal surface that contacts the inner surface of the tapered portion of the flexible tube, and the flexible tube by screwing into the joint tube A cap nut having an outer seal surface that abuts the outer surface of the taper portion of the tube and sandwiches the taper portion with the inner seal surface of the joint tube, and the inner seal at the tip of the joint tube A cylindrical protrusion that extends along the axial direction from the tip of the surface is formed, and the taper angle of the inner seal surface is smaller than the taper angle of the outer seal surface. Pipe joint structure.   The joint structure for a flexible pipe according to claim 1, wherein the outer peripheral surface of the distal end portion of the cylindrical projecting portion is formed into a tapered surface that gradually decreases in diameter toward the distal end.   3. The joint structure for a flexible pipe according to claim 1, wherein an arcuate surface projecting radially inward is formed on the outer seal surface of the cap nut.   The joint structure of a flexible pipe according to any one of claims 1 to 3, wherein a sealing material is applied to both surfaces of the tapered portion of the flexible pipe.

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