JP5130160B2 - Pipe fitting - Google Patents

Description

  The present invention relates to a pipe joint.

After the surface finish of the pipe end, just connecting the pipe end of the connecting pipe into the pipe connecting part completes the connection between the pipe and the joint. A pipe joint called a one-touch joint (see, for example, Patent Documents 1 and 2) There is.
That is, as shown in FIGS. 4 and 5, the pipe joint 100 includes an inner cylinder part 110 inserted inside the pipe end part of the pipe 200 to be connected, and an outer cylinder part 120 surrounding the pipe end part outside. The pipe connection part 130 formed by is provided.

And the inner cylinder part 110 has the packing engaging groove 111 in an outer peripheral surface, and EPDM (ethylene-propylene-) which adheres water tightly to the pipe end part inner wall surface of the pipe | tube 900 by insertion in the pipe end part of the inner cylinder part 110. A cylindrical packing 140 made of a rubber material such as (diene rubber) is externally fitted to the inner cylindrical portion 110 at a packing engaging groove 111 portion.
Further, a protrusion 112 is provided in a ring shape in the circumferential direction in the middle of the packing engagement groove 111 in the tube axis direction, and is provided on the protrusion 112 of the cylindrical packing 140 fitted on the packing engagement groove 111 portion. Concave portions 141 are provided in the corresponding portions, and the protrusions 112 are fitted into the concave strips 141 so that the cylindrical packing 140 is not displaced in the tube axis direction when the tube end portion is inserted.

On the other hand, recently, it is desired to further improve the durability such as heat resistance of the cylindrical packing, and instead of the general-purpose synthetic rubber material such as EPDM for the cylindrical packing, fluorine excellent in durability such as heat resistance and chlorine water resistance. It has been studied to use rubber.
However, in the case of fluorine rubber, unlike the general-purpose synthetic rubber material, it is hard and hardly elastically deformed. Therefore, in the structure of the cylindrical packing 140 in which the concave strip 141 is undercut, tearing, chipping, etc. occur and the quality varies. At present, there has been a problem in applying fluorine rubber to the cylindrical packing.

JP 2006-138378 A JP 2004-324858 A

  In view of the circumstances described above, an object of the present invention is to provide a pipe joint that is provided with a cylindrical packing made of a fluorine-based rubber having good moldability and is excellent in heat resistance and chlorine water resistance.

In order to achieve the above object, a pipe joint according to the present invention includes a pipe connecting part having an inner cylinder part inserted inside a pipe end part of a pipe to be connected and an outer cylinder part surrounding the pipe end part outside. The inner cylindrical portion has a packing engaging groove on the outer peripheral surface, and the cylindrical packing that is watertightly adhered to the inner wall surface of the tube by insertion into the tube end portion of the inner cylindrical portion is formed in the packing engaging groove portion. In the pipe joint that is externally fitted to the cylindrical portion, the packing engaging groove has a two-stage groove structure including a deep groove portion on the distal end side of the inner cylindrical portion and a shallow groove portion on the proximal end side of the inner cylindrical portion. The cylindrical packing is made of fluorine-based rubber and is bonded only on the bottom surface of the deep groove portion.
Further, the pipe joint of the present invention has a pipe joint at a portion facing the core layer at the pipe end of the inner wall surface of the pipe connection portion when a three-layer pipe having an aluminum core layer and an inner / outer layer made of a thermoplastic resin is connected. It is preferable that a ring-shaped groove portion that is recessed from the inner wall surface of the connection portion inner wall surface is formed.

In the present invention, the fluorine-based rubber is not particularly limited, but for example, those satisfying the conditions of hardness (durometer A) of 70 or more, tensile strength of 16 to 22 MPa, elongation at break of 260 to 400% are preferable, FP29 (hardness (durometer A) 72, tensile strength 19.7 MPa, elongation at cutting 320%) manufactured by NOK Corporation can be used as a commercial product.
The adhesive is not particularly limited as long as fluorine rubber can be adhered, but, for example, a modified silicone resin adhesive is preferable.

  As described above, the pipe joint according to the present invention has a two-step groove structure in which the packing engaging groove includes the deep groove portion on the distal end side of the inner cylinder portion and the shallow groove portion on the proximal end side of the inner cylinder portion. Therefore, the cylindrical packing fitted in the packing engaging groove can be formed without an undercut portion. That is, the cylindrical packing can be molded without variability in quality with a fluorine-based rubber having excellent heat resistance and chlorine water resistance without causing tearing or chipping. Therefore, a fluorine rubber cylindrical packing excellent in heat resistance and chlorine water resistance can be used, and a stable sealing state can be maintained even when used in a hot water supply pipe.

In addition, since the cylindrical packing is adhered only to the bottom surface of the deep groove portion, the cylindrical packing does not come out of the packing engaging groove smoothly and accurately when the connection pipe is inserted into the pipe connection portion. Can be inserted into.
And since the shallow groove part side of a cylindrical packing is a non-adhesion state, it adheres to the internal peripheral surface of the pipe | tube connected while a cylindrical packing is extended in an insertion direction, being compressed with pipe insertion, and becomes a watertight state reliably. .

  Further, when a three-layer pipe having a core layer made of aluminum and an inner / outer layer made of a thermoplastic resin is connected, the inner wall surface of the inner wall surface of the pipe connecting portion faces the portion of the inner wall surface of the pipe connecting portion facing the pipe end core layer. If the concave ring-shaped groove portion is formed, even if the pipe joint is made of a conductive metal material such as gun metal, the core layer aluminum and the pipe joint are not in direct contact with each other. Accordingly, it is possible to prevent the occurrence of a galvanic cell due to the contact of different metals and to prevent the deterioration of the strength of the tube due to the corrosion of the core layer.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
FIG. 1 shows one embodiment of a pipe joint according to the present invention.

As shown in FIG. 1, this pipe joint 1 includes a pipe joint main body 2, an outer cylinder member 3 and a cap nut 4 constituting an outer cylinder portion, a cylindrical packing 5, and a retaining ring 6. Is formed.
The pipe joint body 2 is made of a metal material such as lead-free bronze or gun metal, and has a flange portion 2a having a substantially hexagonal cross section at an intermediate portion. One side of the flange portion 2a is a screw tube portion 2b and the other is an inner portion. A tube forming portion 2c is provided.

The inner cylinder forming part 2 c includes a large diameter part 21 and an inner cylinder part 22. The large-diameter portion 21 is provided with a locking recess 21a on the outer peripheral surface thereof, into which a locking protrusion 31 of the outer cylinder member 3 described later is fitted.
The inner cylinder part 22 is provided with a packing engaging groove 23 into which a cylindrical packing 5 described later is fitted on the outer peripheral surface of the intermediate part.

As shown in FIGS. 1 and 2, the packing engaging groove 23 has a deep groove portion 23a on the distal end side of the inner cylinder portion 22, that is, an open end side of the inner cylinder portion 22, and a proximal end side of the inner cylinder portion 22, that is, It has a two-step groove structure including a shallow groove portion 23b on the flange portion 2a side.
The step between the deep groove portion 23a and the shallow groove portion 23b (the height from the bottom of the deep groove portion 23a to the bottom of the shallow groove portion 23b) is preferably 0.1 mm to 0.4 mm. That is, if the level difference is too small, the effect of preventing the displacement of the cylindrical packing 5 cannot be expected, and even if the level difference is large, there is no problem in the effect of preventing the displacement of the cylindrical packing 5. This is because the thickness is thin and there is a risk of problems in strength.

The outer cylinder member 3 is made of a metal material such as lead-free bronze or gun metal, and has a fitting portion 3a having an axial length shorter than the large-diameter portion 21 at one end portion, and the remaining portion is an outer cylinder forming portion 3b. ing.
And as for the outer cylinder member 3, while the latching convex part 31 provided in the internal peripheral surface of the fitting part 3a fits in the latching recessed part 21a of the large diameter part 21, the end surface of the fitting part 3a is the flange part 2a. The fitting portion 3a is fitted to the large diameter portion 21 so as to be in contact with the pipe joint, and is integrated with the pipe joint main body 2 to constitute a part of the outer cylinder portion.

The outer cylinder forming part 3b has an inner diameter larger than that of the fitting part 3a, and forms a tubular pipe connecting part 7 between the outer cylinder forming part 3b and the inner cylinder part 22.
Further, the outer cylinder forming portion 3b is provided with a cap nut mounting portion 32 provided with a locking concave portion 32a in which a locking convex portion 42a of the cap nut 4 described later is fitted on the outer peripheral surface of the other end side of the outer cylindrical member 3. The inner peripheral surface is provided with a notch 33 that forms a receiving recess of a retaining ring 6 to be described later.

A ring-shaped groove 71 formed between the non-fitting portion of the large diameter portion 21 and the outer cylinder forming portion 3b is provided on the end surface of the pipe connecting portion 7 on the flange portion 2a side.
When the three-layer pipe 8 provided with the core layer 81 made of aluminum and the inner and outer layers 82 and 83 made of thermoplastic resin is connected, the ring-shaped concave groove portion 71 comes to a position facing the core layer 81. ing.

The cylindrical packing 5 is obtained by injection-molding fluorine rubber, and has a substantially triangular cross section that gradually decreases in diameter toward one end on the outer peripheral surface of one end across the flat portion 51 as shown in FIG. A triangular protrusion 52 is provided, and a semicircular protrusion 53 having a substantially semicircular cross section having a height substantially the same as that of the triangular protrusion 52 is provided in a portion slightly entering one end side from the other end.
Further, the cylindrical packing 5 has a small inner diameter portion 54 having an inner diameter which is the same as or slightly smaller than the outer diameter of the deep groove portion 23a, and a larger inner diameter whose inner diameter is the same or slightly smaller than the outer diameter of the shallow groove portion 23b. Part 55 is formed.

The difference in diameter between the small inner diameter portion 54 and the large inner diameter portion 55 is the same as the difference in depth between the deep groove portion 23a and the shallow groove portion 23b.
The width of the small inner diameter portion 54 is slightly smaller than the width of the deep groove portion 23a, and the width of the large inner diameter portion 55 is slightly smaller than the width of the shallow groove portion 23b.

The cylindrical packing 5 is externally fitted into the packing engagement groove 23 so that the small inner diameter portion 54 is fitted into the deep groove portion 23a and the large inner diameter portion 55 is fitted into the shallow groove portion 23b, and the inner peripheral surface of the small inner diameter portion 54 is a deep groove. Adhered to the bottom surface of the portion 23a via a modified silicone resin adhesive 9, gaps S1 and S2 are formed between both ends of the cylindrical packing 5 and the side wall of the packing engaging groove 23.
In addition, the boundary position between the deep groove portion 23a and the shallow groove portion 23b is arranged at a position intermediate between the triangular protrusion 52 and the semicircular protrusion 53 from the position facing the end of the triangular protrusion 52 on the semicircular protrusion 53 side. It is preferable. That is, if it is too far, the dering prevention function is not sufficiently effective, and if it is too far, the step at the boundary between the deep groove 23a and the shallow groove 23b and the pressing force at the triangular protrusion 52 are shifted and the dering prevention function is not sufficiently effective. At the same time, the insertion force increases. Further, it is preferable that the gaps S1 and S2 have a minimum size such that the cylindrical packing 5 is compressed and elastically deformed as the tube is inserted, and is filled with the elastically deformed portion. It can be determined as appropriate according to the size of the triangular protrusion 52 and the semicircular protrusion 53 of the cylindrical packing 5.

  The retaining ring 6 is made of a metal material such as gun metal and is accommodated in the notch 33, and an inclined surface 61 corresponding to an inclined surface 43 of the cap nut 4 described later is provided on the outer peripheral surface along the circumferential direction. The outer peripheral surface of the tube end portion of the three-layer tube 8 having a ring shape having a slit (not shown) along the axial direction and capable of expanding and contracting, and the inner peripheral surface thereof being inserted into the tube connecting portion 7 by the contraction. It is supposed to bite into.

The cap nut 4 is made of a metal material such as lead-free bronze or gun metal, and has one end serving as a tube insertion port 41 into which the three-layer tube 8 can be inserted, and the other end fitted to the cap nut mounting portion 32. A fitting portion 42 is provided, and a locking convex portion 42a provided on the inner peripheral surface of the fitting portion 42 is fitted into a locking concave portion 32a of the outer cylindrical member 3, and is integrated with the outer cylindrical member 3 and externally attached. The remainder of the tube portion is configured.
Further, the cap nut 4 has an inclined surface 43 whose inner peripheral surface on the tube insertion port 41 side is gradually reduced in diameter toward the tube insertion port 41.

  In FIG. 1, R is a seal ring made of a rubber material such as EPDM (ethylene-propylene-diene rubber), and is inserted into the notch 33 while being fitted on the outside of the retaining ring 6. It is accommodated together with the stop ring 6.

This pipe joint 1 is configured as described above, and as shown in FIG. 3, a one-touch operation is performed simply by inserting the pipe end portion of the three-layer pipe 8 to be connected from the pipe insertion port 41 into the pipe connection portion 7. Thus, it is possible to connect to a state in which the removal can be prevented by the retaining ring 6.
That is, when the three-layer pipe 8 is pulled in the pulling direction while being pressed against the inner peripheral surface of the pipe end portion of the three-layer pipe 8 to which the cylindrical packing 5 is connected by insertion, the seal is secured. The ring 6 is reduced in diameter by sliding the inclined surface 61 so as to follow the inclined surface 43 of the cap nut 4 and bites into the outer peripheral surface of the three-layer pipe 8 to prevent the three-layer pipe 8 from coming out of the pipe joint 1. To do.

And since the cylindrical packing 5 is formed with the fluorine-type rubber | gum excellent in heat resistance and chlorine-resistant water, when using it for piping for hot water supply, the stable sealing state can be maintained. Moreover, since there is no undercut portion on the inner peripheral surface of the cylindrical packing 5, even if it is a fluorinated rubber, a fluorinated rubber cylindrical packing excellent in heat resistance and chlorine water resistance is molded without variation in dimensional accuracy. it can.
Further, as shown in FIG. 2, since the cylindrical packing 5 is bonded only on the bottom surface of the deep groove portion 23 a, the cylindrical packing 5 is inserted when the tube end portion of the three-layer tube 8 is inserted into the tube connection portion 7. Can be inserted smoothly and accurately without being removed from the packing engaging groove 23. And since the shallow groove part 23b side of the cylindrical packing 5 is a non-adhesion state, the cylindrical packing 5 is extended with the insertion of the tube, and extends in the insertion direction, fills the gaps S1 and S2, and is connected. It adheres closely to the inner peripheral surface of the tube end, and is surely watertight.

  Further, since the ring-shaped concave groove portion 71 is provided, when the three-layer pipe 8 including the core layer 81 made of aluminum and the inner and outer layers made of polyethylene resin is connected, the core layer 81 is never on the wall surface of the pipe joint. There is no contact. Therefore, generation of a galvanic cell due to contact of different metals can be prevented, and deterioration of the strength of the tube due to corrosion of the core layer 81 can be prevented.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the outer cylinder member is a metal material. However, the outer cylinder member is formed of a transparent resin such as polyphenylsulfone so that it can be confirmed whether or not the connection of the pipe is normally completed. It doesn't matter.
In the above-described embodiment, the one-touch joint is used. However, the joint may be a joint that retains the diameter-reducing ring accommodated in the cap nut by tightening the cap nut after connecting the pipe to prevent the cap nut from coming off. .

In the above embodiment, the pipe to be connected is a three-layer pipe, but it can also be used to connect a single-layer pipe such as a crosslinked polyethylene pipe.
In the above embodiment, the pipe joint main body and the outer cylindrical member, and the outer cylindrical member and the cap nut are fitted and joined to the locking convex portion and the locking concave portion, respectively, but may be screwed. .

  Although the pipe joint concerning this invention is not specifically limited, For example, it is used for connection of piping, such as hot water supply and water supply.

It is sectional drawing showing one embodiment of the pipe joint concerning this invention. It is a principal part expanded sectional view of the pipe joint of FIG. It is sectional drawing showing the state which connected the pipe | tube to the pipe joint of FIG. It is a half sectional view of the conventional pipe joint. It is principal part sectional drawing of the pipe joint of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe joint 2 Pipe joint main body 2c Inner cylinder formation part 22 Inner cylinder part 23 Packing engagement groove 23a Deep groove part 23b Shallow groove part 3 Outer cylinder member (outer cylinder part)
4 Cap nut (outer cylinder)
5 Cylindrical packing 7 Pipe connection portion 71 Ring-shaped concave groove portion 8 Three-layer tube (tube to be connected)
81 Core layer 82 Inner layer 83 Outer layer 9 Adhesive

Claims (2)

A tube connecting portion having an inner cylinder portion inserted inside the tube end portion of the tube to be connected, and an outer cylinder portion surrounding the tube end portion outside;
The inner cylindrical portion has a packing engaging groove on the outer peripheral surface, and a cylindrical packing that is in close contact with the inner wall surface of the tube by insertion into the tube end portion of the inner cylindrical portion is formed on the inner cylindrical portion at the packing engaging groove portion. In pipe fittings that are externally fitted,
The packing engaging groove has a two-stage groove structure including a deep groove portion on a distal end side of the inner cylinder portion and a shallow groove portion on a proximal end side of the inner cylinder portion,
A pipe joint, wherein the cylindrical packing is made of fluorine-based rubber and is bonded only on the bottom surface of the deep groove portion.   When connecting a three-layer pipe with a core layer made of aluminum and an inner and outer layer made of a thermoplastic resin, the part that faces the core layer at the pipe end of the inner wall surface of the pipe connection part is recessed from the other part of the inner wall surface of the pipe connection part The pipe joint according to claim 1, wherein a ring-shaped concave groove is formed.

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