JPH1026270A - Socket structure with rubber ring mounting groove and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve resistance against pressure of a socket part by bonding an inner layer which is provided with a rubber ring mounting groove on its inner circumferential face and consists of a cylindrical body made of anticorrosive metal and an outer layer which is formed along an outer face of the cylindrical body by press-fitting the cylindrical body in one end of a synthetic resin pipe which is in a softened condition on their boundary face. SOLUTION: This socket part is provided with an inner layer and an outer layer, and a rubber ring mounting groove 71 in which a rubber ring can be mounted on its inner circumferential face is provided. This receive port part is formed by preparing a pipe 6 made of polyethylene which becomes the outer layer and a cylindrical body 7 made of stainless steel which becomes the inner layer, softening the pipe 6 by heating it, and then press-fitting the cylindrical body 7 into the pipe 6. At this time, a part on a tip side of the pipe 6 is expanded until its diameter becomes substantially the same as a diameter of a swelled part 72 of the cylindrical body 7 once due to the press-fitting of the cylindrical body 7. After that, however, it is shrunk naturally so that the pipe 6 adheres on the cylindrical body 7 closely. Next, the cylindrical body 7 is heated by using high frequency to melt an inner face of the pipe 6 on a boundary face of the cylindrical body 7 and is cooled to obtain the socket part 1 in which the inner layer and the outer layer are bonded and integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a socket structure having a groove for mounting a rubber ring and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a pipe joint provided with a socket having a rubber ring mounting groove at an end thereof has been disclosed in Japanese Patent Application Laid-Open Nos. 54-81382 and 58-96512. ,
Prepare a mold having a cavity corresponding to the cross-sectional shape of the receiving part, fit one end of the synthetic resin tube softened by heating into the cavity of this mold, and attach the tube end of the synthetic resin tube. It is manufactured by a method of forming by expanding the diameter into a cavity shape, or a method of forming a receiving portion by injection molding or the like, and then integrating the receiving portion and the main body portion by heat fusion.

[0003] However, if the port is formed by the former method using a tube made of a crystalline resin such as polyethylene, the crystalline resin has a glass transition temperature much lower than room temperature. The part which is formed by expanding the diameter gradually reduces its diameter to the original state after the molding. Moreover,
Since the diameter is reduced at a different ratio depending on the molding conditions, the inner diameter of the receiving port is not stable. Further, since the receiving portion is formed by expanding the diameter of the synthetic resin pipe, the thickness of the receiving portion is inevitably reduced, and there is a problem that the internal pressure resistance of the receiving portion is lower than that of the synthetic resin tube.

On the other hand, in the case of the latter method, the above problem does not occur, but it is necessary to form the receiving portion in advance by injection molding or the like, and the receiving portion must be integrated with the main body portion by heat fusion. The process is complicated. Moreover,
Poor bonding, oxide film on the surface,
There is a problem in the reliability of the fused portion, for example, there is a possibility of causing a joining defect due to dirt. In addition, when fusion is performed by butt fusion or the like, a bead is inevitably formed on the inner surface of the joint, and the bead causes a step on the inner surface, which may cause clogging or the like.

Further, according to the conventional socket structure, since the entire socket portion is formed of synthetic resin, when receiving a high internal pressure due to an increase in water pressure or the like, the diameter of the socket portion increases, and the port portion and the port portion are enlarged. The gap between the socket and the receiving port becomes large, and the rubber ring protrudes from this gap, which may impair the water stopping performance.

[0006]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention makes it possible to easily form a socket at the end of a pipe using a pipe made of a crystalline resin such as polyethylene. An object of the present invention is to provide a receiving structure having a rubber ring mounting groove excellent in pressure resistance of a receiving portion and a method of manufacturing the same.

[0007]

In order to achieve the above object, a receiving structure with a rubber ring mounting groove according to the invention of claim 1 (hereinafter referred to as a "receiving structure of claim 1") is provided. An inner layer made of a corrosion-resistant metal tubular body having an inner peripheral surface provided with a rubber ring mounting groove formed by bulging a wall outward, and the tubular body is press-fitted into one end of a softened synthetic resin pipe. And an outer layer formed along the outer surface of the cylindrical body, and the inner layer and the outer layer are bonded at the interface.

The method of manufacturing the socket structure with a rubber ring mounting groove according to the second aspect of the present invention (hereinafter referred to as "the manufacturing method of the second aspect") is to start the synthetic resin pipe from one end of the softened synthetic resin pipe. Inside, a step of press-fitting a cylindrical body of corrosion-resistant metal having a rubber ring mounting groove formed on the inner peripheral surface formed by bulging the wall surface outward, and heating the cylindrical body to form an interface between the cylindrical body and the interface. Melting the inner wall surface of the synthetic resin pipe and bonding the synthetic resin pipe and the cylindrical body.

The receiving structure with a rubber ring mounting groove according to the invention of claim 3 (hereinafter referred to as “receiving structure of claim 3”)
An inner layer made of a corrosion-resistant metal cylindrical body having a rubber ring mounting groove formed on the inner peripheral surface formed by bulging a wall surface outward, and the cylindrical body is press-fitted into one end of a softened synthetic resin pipe. Having an outer layer formed along the outer surface of the tubular body, between the inner layer and the outer layer, a ring-shaped elastic seal layer is formed so as to partially surround the inner layer, and the remaining inner layer and The outer layer was bonded.

[0010] The method for manufacturing the rubber ring mounting grooved socket structure according to the invention of claim 4 (hereinafter referred to as "manufacturing method of claim 4") is a method for manufacturing an olefin resin pipe from one end of a softened synthetic resin pipe. Inside, a cylindrical body of a corrosion-resistant metal, which has a rubber ring mounting groove formed by bulging a wall surface on the inner peripheral surface and a ring-shaped elastic sealing material is partially fitted on the inner peripheral surface, is press-fitted. And a step of heating the tubular body to melt the inner wall surface of the synthetic resin pipe at the interface of the tubular body and bonding the synthetic resin pipe to the tubular body.

[0011] In the constructions of the first to fourth aspects, the synthetic resin tube is not particularly limited, and examples thereof include a tube made of polyethylene, polypropylene, polyvinyl chloride and the like. The tubular body is not particularly limited as long as it has corrosion resistance. Generally, a tubular body made of stainless steel is suitably used, and a thin body as much as possible is preferred.

The method for heating the cylindrical body is not particularly limited, and includes, for example, a high-frequency heating method. The ring-shaped elastic sealing material is not particularly limited, but for example, a rubber excellent in heat resistance such as ethylene-propylene-diene terpolymer (EPDM) or styrene-butadiene rubber (SBR) is preferable.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the receptacle structure of the first aspect. As shown in FIG. 1, the receiving portion 1 includes an inner layer 2 made of stainless steel and an outer layer 3 made of polyethylene, and the inner layer 2 and the outer layer 3 are bonded and integrated at an interface between the inner layer 2 and the outer layer 3. A rubber ring mounting groove 11 into which the rubber ring 4 can be mounted is recessed.

The outer layer 3 is provided so as to be connected to one end of the main body 5 having a straight tubular shape. And this receiving part 1 is obtained as follows.

First, as shown in FIG. 2, a cylinder having a polyethylene pipe 6 and a groove 71 which is a rubber ring mounting groove formed by bulging a stainless steel wall outwardly is formed on the inner peripheral surface. After preparing the tubular member 7 and heating the tube 6 to a softened state, the tubular member 7 is pressed into the inside of the tube 6 from the tube end of the tube 6. The tube 6 is pressed into the tubular body 7 by press-fitting the tubular body 7.
The portion on the tip end side of the tube 6 from the bulging portion 72 is once expanded to a diameter substantially the same as the diameter of the bulging portion 72 of the tubular body 7, but since the glass transition temperature of polyethylene is low, the inner surface of the tube 6 Naturally contracts so as to be in close contact with the outer surface of the tubular body 7.

Next, the end of the tube 6 into which the tubular body 7 is press-fitted is inserted into an induction coil (shown in the figure), and the tubular body 7 is heated to a temperature higher than the melting point of polyethylene by high frequency. After the inner surface of the tube 6 at the interface of the cylindrical body 7 is melted and then cooled, as shown in FIG.
And a main body portion comprising a polyethylene outer layer 3 formed by enlarging the diameter of the pipe end of the pipe 6, and a receptacle 1 in which the inner layer 2 and the outer layer 3 are bonded and integrated with each other. 5 can be provided continuously at one end.

According to such a structure of the receiving portion 1, the thickness of the outer layer 3 of the receiving portion 1 becomes thinner than the original thickness of the main body portion 5, ie, the pipe 6, but the inner layer 2 is made of a stainless steel cylinder. Since the inner layer 2 is formed by the body 7, the hoop stress due to the internal pressure is shared, and the hoop stress σ (σ = (D−t) P / 2t, D: outer diameter,
t: wall thickness, P: internal pressure).

Therefore, the receiving portion 1 has a strength higher than the original strength of the main body portion 5, that is, the tube 6, and can be used as a pressure tube. Needless to say, there is no accident such as the rubber ring 4 jumping out due to the expansion of the diameter of the receiving portion 1, and sufficient water stoppage can always be ensured. In addition, since the outer layer 3 of the receptacle 1 is formed by enlarging one end of the pipe 6, there is no need to weld the main body later, and the gap between the receptacle 1 and the main body 6 is eliminated. There is no step on the inner surface of the device, which causes clogging.

FIG. 3 shows an embodiment of the socket structure according to the third aspect. As shown in FIG. 3, the receptacle 8
An inner layer 2 made of stainless steel and an outer layer 3 made of polyethylene are provided, and a ring-shaped elastic seal layer 9 is provided at a part between the inner layer 2 and the outer layer 3 so as to surround the outer peripheral surface of the inner layer 2. It is the same as the receptacle 1 except that the inner layer 2 and the outer layer 3 are bonded and integrated at the interface.

As shown in FIG. 4, the receiving portion 8 is provided with a ring-shaped elastic sealing layer 9 in advance in the cylindrical body 7.
A method of manufacturing the receiving portion 1 except that a ring-shaped elastic sealing material 9 'to be formed is fitted outside, and the cylindrical body 7 is press-fitted into the pipe 6 together with the ring-shaped elastic sealing material 9'. Is similar to According to such a structure of the receiving portion 8, the same effect as the structure of the receiving portion 1 of FIG. 1 is provided, and since the elastic sealing layer 9 is provided, an interface between the inner layer 2 and the outer layer 3 is provided. Even when the adhesion is insufficient, the elastic sealing layer 9 can be completely adhered to the inner layer 2 and the outer layer 3 to completely prevent the fluid in the pipe from flowing outside through the gap between the inner layer 2 and the outer layer 3. it can.

Further, according to the above-described manufacturing method, the ring-shaped elastic sealing material 9 'is provided from the bulging portion 72 of the tubular body 7 toward the distal end of the tube 6, so that the ring-shaped elastic sealing material 9' is press-fitted. 'Can be press-fitted together with the tubular body 7 without causing a positional shift.

The present invention is not limited to the above embodiment. For example, in the method for manufacturing the receiving portion 8, the ring-shaped elastic sealing material 9 'is fitted outside the bulging portion 72 of the tubular body 7 on the tip side. If a recessed portion into which the elastic sealing material 9 ′ is fitted is provided, it may be fitted outside the bulging portion 72 on the main body portion 5 side. Of course, it may be provided before and after the bulging portion 72.

[0023]

As described above, the socket structure and the method of manufacturing the same according to the present invention use a tube made of a crystalline resin such as polyethylene and have excellent pressure resistance easily at the end of the tube. Can be formed.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing an embodiment of a socket structure of the first embodiment.

FIG. 2 is a half sectional view for explaining an embodiment of a method of manufacturing the receiving structure of FIG. 1 (a manufacturing method of claim 3).

FIG. 3 is a half sectional view showing an embodiment of the receptacle structure of claim 2;

FIG. 4 is a half sectional view illustrating an embodiment of a method for manufacturing the receiving structure shown in FIG. 3 (a manufacturing method according to claim 4).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiving part 11 Rubber ring mounting groove 2 Inner layer 3 Outer layer 4 Rubber ring 6 Tube 7 Cylindrical body 71 Groove which becomes a rubber ring mounting groove 72 Swelling part 8 Receptacle 9 Elastic seal layer 9 'Ring-shaped elastic seal material

Claims (4)

[Claims] 1. An inner layer made of a corrosion-resistant metal tubular body having an inner peripheral surface provided with a rubber ring mounting groove formed by bulging a wall surface to the outside, and the tubular member formed at one end of a softened synthetic resin pipe. A receiving structure with a rubber ring mounting groove, comprising: an outer layer formed so that a body is press-fitted and formed along the outer surface of the cylindrical body, and the inner layer and the outer layer are bonded at an interface thereof. 2. A cylindrical body made of a corrosion-resistant metal having a rubber ring mounting groove formed on the inner peripheral surface formed by bulging a wall surface from one end of a synthetic resin tube in a softened state into the synthetic resin tube. The rubber ring mounting according to claim 1, further comprising a step of press-fitting, and a step of heating the cylindrical body to melt an inner wall surface of the synthetic resin pipe at an interface of the cylindrical body, and bonding the synthetic resin pipe and the cylindrical body. Manufacturing method of grooved socket structure. 3. An inner layer made of a corrosion-resistant metal tubular body having an inner peripheral surface provided with a rubber ring mounting groove formed by bulging a wall surface to the outside, and said tubular member being attached to one end of a softened synthetic resin pipe. A body is press-fitted and has an outer layer formed along the outer surface of the cylindrical body, and a ring-shaped elastic seal layer is formed between the inner layer and the outer layer so as to partially surround the inner layer. A rubber ring mounting grooved receiving structure in which the inner layer and the outer layer are adhered to the rest. 4. A rubber ring mounting groove formed by bulging a wall surface from the one end of a softened synthetic resin tube into an olefin resin tube on an inner peripheral surface, and a ring-shaped elastic part is partially formed. A step of press-fitting the corrosion-resistant metal tubular body in which the sealing material is fitted, and heating the tubular body to melt the inner wall surface of the synthetic resin pipe at the interface of the tubular body, and the synthetic resin pipe and the tubular body Bonding the rubber ring mounting groove according to claim 3.