JPH09170685A - Tube joint and its forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of the water securely, by injecting a thermoplastic resin to an integral article including a second part of a material with no mutual sloving property with a thermoplastic resin; a sleeve; and a seal ring between both members; and molding integral with a first part. SOLUTION: A seal ring 30 is installed to a seal ring installing groove 24 of a second part 18 which consists of a metal such as iron, and a synthetic resin such as an engineering plastic, a sleeve 32 is installed to the outer peripheral surface of a main body 20 in order to compress the seal ring 30, and a clearance between the second part 18 and the sleeve 32 is sealed. After that, an integral article including the second part 18, the seal ring 30, and the sleeve 32 is installed to an injection molding die, and a heated and fused resin such as the polyvinylchloride is injection from an injection molding machine, so as to form a first part 16. Since the heated and fused resin is contacted with the sleeve 32 which has the mutual soluble property with the first part 16 in this case, the first part 16 and the sleeve 32 are integrated. Consequently, even though the clearance between both members is increased by the difference of the thermal expansion coefficient of the first part 16 and the second part 18, the leakage of the water can be prevented securely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint and a method for forming the pipe joint, and more particularly to a pipe joint for connecting, for example, two pipes made of different materials and a method for forming such a pipe joint.

[0002]

2. Description of the Related Art A conventional pipe joint 1 of this type shown in FIG.
The first portion 2 made of synthetic resin and the second portion 3 made of metal are included, and the seal ring 4 is arranged between the first portion 2 and the second portion 3. When molding this pipe joint 1, after mounting the seal ring 4 in the seal ring mounting groove 5 provided in the second portion 3, the seal ring 4
The first portion 2 was injection molded so as to cover the.

[0003]

In the conventional pipe joint 1,
Although the seal ring 4 is compressed by the injection pressure of the resin that molds the first portion 2 to seal the gap between the first portion 2 and the second portion 3, the injection pressure of the resin is not sufficient. The seal ring 4 could not be compressed sufficiently, and the performance of the seal ring 4 could not be fully exhibited. Therefore, there is a possibility that water or the like flowing through the pipe line 6 including the pipe joint 1 may leak to the outside through the gap between the first portion 2 and the second portion 3. Since the gap between the first part 2 and the second part 3 is mainly caused by the difference in the coefficient of thermal expansion between the two, there is a high possibility that water leakage will occur especially in an environment where temperature changes occur. .

Therefore, a main object of the present invention is to provide a pipe joint and a method for forming the pipe joint which can surely prevent water leakage.

[0005]

A first aspect of the present invention is a method for molding a pipe joint in which a first portion made of a thermoplastic resin is integrally formed with a second portion made of a material incompatible with the thermoplastic resin. Where (a) an integral body including the second portion, a sleeve, and a seal ring arranged between the second portion and the sleeve is prepared, and (b) a thermoplastic resin is injected to 1
A method for forming a pipe joint, in which a part and an integrated body are integrally formed.

The second invention is the first invention which is made of a thermoplastic resin.
A sleeve is a pipe joint that comprises a portion, a second portion made of a material that is incompatible with a thermoplastic resin, and a seal ring disposed between the second portion and the sleeve, the sleeve compressing the seal ring.

[0007]

Since the seal ring is compressed by the sleeve, the performance of the seal ring can be fully exhibited.

[0008]

According to the first and second aspects of the present invention, water leakage can be reliably prevented. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pipe joint 10 of this embodiment shown in FIG.
As shown in FIG. 3, the first pipe 12 made of a synthetic resin such as polyvinyl chloride and the second pipe 14 made of a metal such as iron are connected to each other and are not compatible with each other. It includes a first portion 16 and a second portion 18 of material. Here, a thermoplastic resin such as polyvinyl chloride, polybutene, polyethylene (polyolefin resin) or the like is used as the material of the first portion 16, and a metal such as iron or the like is used as the material of the second portion 16. Synthetic resins such as engineering plastics may be used.

The second section 18 includes a first tube 12 and a second tube.
Each of the tubes 14 has a substantially cylindrical main body 20 having an inner diameter substantially the same as the inner diameter of the pipe 14. A ring mounting groove 24 and a plurality of (three in this embodiment) engagement grooves 26 are formed. Further, on the outer peripheral surface of the central portion of the main body 20 in the axial direction, a substantially flange-shaped holding portion 28 which is held by a jig (not shown) such as a spanner is formed. Then, the seal ring 3 is inserted into the seal ring mounting groove 24.
The main body 2 has a substantially cylindrical sleeve 32 made of a material compatible with the first portion 16 (for example, polyvinyl chloride) so that the seal ring 30 is compressed.
It is attached to the outer peripheral surface of 0.

The first portion 16 is fitted to the receiving end 34 for receiving the first tube 12 and the other end portion (the end portion on the side where the sleeve 32 is mounted) of the second portion 18 (main body 20). The joint portion 36 is included and integrally molded with the second portion 18 by injection molding. When molding such a pipe joint 10,
First, the separately formed second portion 18 is prepared, and the seal ring 30 is mounted in the seal ring mounting groove 24 of the second portion 18. Then, as shown in FIG. 3, the seal ring 3
The sleeve 3 is attached to the outer peripheral surface of the main body 20 by compressing 0.
2 is attached and the gap between the second portion 18 and the sleeve 32 is sealed. Subsequently, as shown in FIG. 4, an integral body including the second portion 18, the seal ring 30, and the sleeve 32 is attached to the core 40 of the injection molding die 38, and the outer die 42 is closed to open the cavity 44. Form. Then, the resin that has been heated and melted is injected into the cavity 44 from an injection molding machine (not shown) to mold the first portion 16. At this time, the heat-melted resin comes into contact with the sleeve 32 in the cavity 44, so that the surface of the sleeve 32 melts with the injected resin and the first portion 16 and the sleeve 32 are integrated.

When the resin of the first portion 16 is hardened, the outer mold 42 is opened and the pipe joint 10 is removed from the core 40. When connecting the first pipe 12 and the second pipe 14 by using the pipe joint 10, first, one end of the socket 46 is attached to the end of the second pipe 14 as well understood from FIG. 2. The female screw 48 of the pipe joint 10 is screwed into the female screw 48 provided at the other end of the socket 46. Then, an adhesive is applied to the outer peripheral surface of the end portion of the first tube 12, and this end portion is inserted into the receiving port 34 and bonded.

According to this embodiment, the seal ring 30 can be sufficiently compressed by the sleeve 32, so that the gap between the sleeve 32 and the second portion 18 can be sufficiently sealed. In addition, since the sleeve 32 and the first portion 16 are integrated by melting each other, no gap is formed between them. Therefore, in an environment where the temperature changes, even if the gap between the first portion 16 and the second portion 18 becomes large due to the difference in coefficient of thermal expansion, water leakage can be reliably prevented.

In the above-mentioned embodiment, the case where the receiving port 34 of the first portion 16 is formed as an adhesive receiving port is shown. However, as in the pipe joint 50 shown in FIG. 5, the receiving port 34 is fused. It may be formed as a receptacle. In this case, a mat 54 having a heater (heating wire) 52 wound around the outer peripheral surface is prepared, and a part of the mat 54 is a seal ring 30.
Used as a sleeve for compressing.

When molding this pipe joint 50, first,
The seal ring 30 and the mat 54 are attached to the second portion 18, and then the second portion 18 is attached to the core 58 of the injection mold 56 as shown in FIG. Then, the outer mold 60 is closed to form a cavity 62, and a thermoplastic resin is injected into the cavity 62 from an injection molding machine (not shown) to mold the first portion 16. When the first portion 16 is cured, the outer mold 60 is opened and the pipe joint 50 is removed.

Also in this embodiment, since the seal ring 30 can be sufficiently compressed by the mat 54, water leakage from the gap between the first portion 16 and the second portion 18 can be reliably prevented. In each of the above-described embodiments, the seal ring 30 is mounted in the seal ring mounting groove 24 of the second portion 18, and the seal ring 30 is compressed by the sleeve from the outer periphery. Like the joint 64, the seal ring 30 may be compressed from the inner circumference by the sleeve 66, and as in the pipe joint 68 shown in FIG.
The seal ring 30 may be attached to the.

Further, as the heater 52, in addition to the heating wire used in the embodiment of FIG. 5, a magnetic alloy heater or the like which is heated by an electromagnetic induction effect may be used. When the magnetic alloy heater is used, it is not necessary to provide a terminal for connecting a power source, so that the molding can be performed more easily.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention;

FIG. 2 is an illustrative view showing a use state of the embodiment in FIG. 1;

FIG. 3 Second with seal ring and sleeve fitted
It is an illustration figure which shows a part.

FIG. 4 is an illustrative view showing a forming method of the embodiment in FIG. 1;

FIG. 5 is an illustrative view showing another embodiment of the present invention.

FIG. 6 is an illustrative view showing a molding method of the embodiment in FIG. 5;

FIG. 7 is an illustrative view showing another embodiment of the present invention.

FIG. 8 is an illustrative view showing another embodiment of the present invention;

FIG. 9 is an illustrative view showing a conventional technique;

[Explanation of symbols]

 10, 50, 64, 68 ... Pipe joint 12 ... First pipe 14 ... Second pipe 16 ... First part 18 ... Second part 30 ... Seal ring 32 ... Sleeve 52 ... Heater 54 ... Mat

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Kojima 2480 Santo, Hiratsuka-shi, Kanagawa Mitsubishi Plastics Corporation Hiratsuka factory (72) Inventor Akira Miyasa 2 Daifuku, Kuwana-shi, Mie Hitachi Metals Co., Ltd. Kuwana Factory (72) Inventor Hiroshi Oya 2 Daifuku, Kuwana City, Mie Hitachi Metals Co., Ltd. Kuwana Factory (72) Inventor Kazuaki Yamajo 64 Ishizukitacho, Sakai City, Osaka Prefecture Kubota Vinyl Pipe Factory (72) ) Inventor Shinzaburo Oshimo 64 Ishizukita-machi, Sakai City, Osaka Prefecture Kubota Vinyl Pipe Factory Co., Ltd.

Claims (4)

[Claims] 1. A method of molding a pipe joint, wherein a first portion made of a thermoplastic resin is integrally molded with a second portion made of a material incompatible with the thermoplastic resin, the method comprising: (a) the second portion. Preparing an integrated body including a portion, a sleeve, and a seal ring arranged between the second portion and the sleeve, and (b) injecting the thermoplastic resin to form the first portion and the integrated body. A method for forming a pipe joint, in which and are integrally formed. 2. The pipe joint is a fusion splicer in which a heater is installed, the heater is pre-mounted on a mat, and in the step (a), a part of the mat is used as the sleeve. A method for forming the described pipe joint. 3. A first part made of a thermoplastic resin, a second part made of a material incompatible with the thermoplastic resin, a seal ring arranged between the second part and the sleeve, Is a pipe joint that compresses the seal ring. 4. The pipe joint includes a mat to which a heater is attached, and a part of the mat is used as the sleeve.
The pipe joint according to claim 3.