JP3510478B2 - Screw joints such as synthetic resin piping - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a screw joint used for a synthetic resin pipe or the like, which is formed by joining a screw member made of a high-strength material to a part of the tip of a synthetic resin screw portion. Regarding things.

[0002]

2. Description of the Related Art In recent years, examples of using synthetic resin pipes and synthetic resin joints for indoor pipes in houses and the like are increasing. However, since the screw portions of the joints are formed by molding screws, metal screws are used. Its strength was inferior to that of joints, which restricted its use. In particular, in the case of a male screw, since the screw thread is soft when screwed into the mating female screw, it may be screwed diagonally, causing water leakage and the like.

[0003]

In order to make up for the drawbacks of the synthetic resin threaded portion, it has been attempted that only the threaded portion of the resin joint is made entirely of metal. However, between the resin and the metal, There is a problem with the adhesion. Although packing is used to fill the gap, there is a drawback that water leakage or the like easily occurs from this part because the durability of the packing is poor.
Although an O-ring is sandwiched between the metal surface and the resin surface to prevent water leakage, there is a problem with the durability of the O-ring, and such a joint cannot be permanently used without support. It was The present invention seeks to improve the above-mentioned drawbacks by using a metal screw part in a part of a synthetic resin screw joint.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a male threaded joint of a synthetic resin threaded joint, in which the outer portion is a threaded portion having a length of about 1/3 from the tip of the entire threaded portion and the inner portion is A high-strength male screw reinforcing member consisting of a cylindrical body having an inner diameter substantially equal to the length of the entire screw thread portion and having an inner diameter equal to the inner diameter of the synthetic resin male screw joint is provided at the tip portion of the synthetic resin male screw joint. Attach it to the part where the notch of the same shape as the screw reinforcing member is formed, and integrate it. For female threads of synthetic resin screw joints,
The inside consists of a screw thread that is about 1/3 of the length from the tip of the entire screw thread, and the outside is approximately equivalent to the length of the entire screw thread, and its outer diameter is the same as the tip of the female threaded joint made of synthetic resin. A high-strength female thread reinforcing member made of a cylindrical body having a smaller outer diameter is attached to and integrated with a portion of the tip portion of the female thread of the synthetic resin screw joint in which a notch having the same shape as the female thread reinforcing member is formed.

The high-strength male screw reinforcing member and female screw reinforcing member are made of metal such as copper-tin alloy (gun metal), or ceramic, super engineering plastic, or the like, which is stronger than the synthetic resin screw joint body. As a method of attaching the reinforcing member to the synthetic resin screw joint, the male and female screw reinforcing members are set in the mold in advance, and the synthetic resin screw joint portion is integrally formed by insert molding of synthetic resin. Also, after molding the synthetic resin screw joint part,
The screw reinforcing member can be integrated by press fitting, adhesive bonding, heat welding, or the like. Conversely, a synthetic resin screw joint portion may be attached to the screw reinforcing member.

After the high-strength male screw reinforcing member and female screw reinforcing member are integrated with the synthetic resin screw joint portion, the joining of the both is loosened due to the influence of aging, thermal expansion, etc., and the reinforcing member is inside the resin member. There is a risk of spinning around and getting out. In order to prevent this from happening, the screw reinforcing member is made into a shape with an undercut such as knurling in advance and then integrated with the screw joint made of synthetic resin.

The high-strength screw reinforcing member is manufactured by a method suitable for the material such as molding, casting and machining. The synthetic resin screw joints will also be manufactured by molding, machining, etc. In this case, the screw diameter is 7 to 10 according to JIS standard.
If you make it so that it can handle all standard screws up to 0, combine a synthetic resin screw joint with a male screw reinforcing member or female screw reinforcing member with a conventional synthetic resin screw joint or metal screw joint. It can also be used as a wide range of uses.

[0008]

In the present invention, since the screw joint made of synthetic resin is formed in this way, even in the field where the conventional screw joint made only of synthetic resin cannot be used due to its insufficient strength, it is similar to the metal joint. Can be used for To prevent leakage of the fluid in the pipe, even when the high-strength male screw reinforcing member and female screw reinforcing member are screwed together,
About one-third of the central portion of the entire thread portion is a male and female screw portion made of synthetic resin, so that the resin screw portion completely seals and there is no leakage. Further, it can be manufactured at a lower cost than the one in which the entire threaded portion of the resin screw joint is made of metal as described above.

[0009]

EXAMPLE As an example of the present invention, a cross section of a male screw joint 1 made of synthetic resin is shown in FIG. 1 (a), and a sketch of a high strength male screw reinforcing member at the tip is shown in (b). The outside consists of a male screw thread portion 3 having a length of about 1/3 from the tip of the entire screw thread portion 2, the inside substantially corresponds to the length of the whole screw thread portion 2, and the inner diameter thereof is a synthetic resin male screw joint. A high-strength male screw reinforcing member 5 composed of a cylindrical body 4 having the same inner diameter as that of the male screw reinforcing member 5 is attached to and integrated with a notch portion of the same shape as the male screw reinforcing member 5 at the tip portion of the synthetic resin male screw joint. A male screw joint 1 of a synthetic resin screw joint is formed. The male screw reinforcing member 5 has a shape with an undercut 6 such as knurled beforehand so as to improve the connection with the resin.

Similarly, as one embodiment of the present invention, a cross section of a female screw joint 7 made of synthetic resin is shown in FIG. The inside consists of a female screw thread portion 8 having a length of about 1/3 from the tip of the whole screw thread portion 2, the outside is substantially equivalent to the length of the whole screw thread portion 2, and the outer diameter thereof is a synthetic resin female screw. Cylindrical body 9 smaller than the outer diameter of the tip of the joint
The high-strength female screw reinforcing member 10 made up of the above-mentioned female screw reinforcing member 1 at the tip of the female screw of the female screw joint 6 made of synthetic resin.
It is attached to a portion having a notch having the same shape as that of 0 and integrated with each other to form a female screw joint 6 of a synthetic resin screw joint.

As a material of the screw joint reinforcing member, an intermetallic compound (gun metal) having a ratio of copper to tin of 1.9 to 1 is used. According to other uses, it can be formed of a material having higher strength than the synthetic resin screw joint main body portion such as fine ceramic or super engineering plastic. Further, as the material of the synthetic resin screw joint main body, polybutene resin, polyvinyl chloride, polypropylene, polyethylene, liquid crystal polymer, polycarbonate, polysulfone, polysulfene sulfide, polyacetal, modified polyphenylene ether, crosslinked polyethylene and the like are used.

In order to manufacture the screw joints 1 and 6 made of synthetic resin, the high-strength screw joint reinforcing members 5 and 10 are set in advance in the mold, and are integrally molded with the synthetic resin screw joint portion by insert molding of synthetic resin. To do. After molding the synthetic resin screw joint portion, the screw reinforcing members 5 and 10 can be integrated by press fitting, adhesive bonding, heat welding, etc.
In the case where the working process becomes complicated and a gap is generated between the metal and the synthetic resin member, it is necessary to separately prepare a backing material and fill the gap portion.

For comparison with the synthetic resin screw joint of the present invention, FIG. 3 shows a female screw joint in which only the screw portion of the conventional resin joint is made entirely of metal. In the conventional products, after molding each, a metal member is bonded to the synthetic resin main body with an adhesive, but there is a problem in the adhesion between the resin and the metal. Although the packing 11 is used to fill the gap, there is a drawback that water leakage easily occurs from this portion because the packing has poor durability.

[Brief description of drawings]

FIG. 1 is a sectional view of a right half of a male screw joint made of synthetic resin according to the present invention in (a) and a sketch of a reinforcing member in (b).

FIG. 2 is a partial cross-sectional view of a synthetic resin female and male screw joint of the present invention.

FIG. 3 is a sectional view of a female portion of a conventional resin screw joint.

[Explanation of symbols]

1 Male screw joint 2 All screw threads 3 male screw thread 4 cylindrical body 5 Male screw reinforcement member 6 undercut 7 Female threaded joint 8 Female thread ridge 9 cylindrical body 10 Female screw reinforcing member 11 packing

Continuation of the front page (56) Reference JP-A-50-135582 (JP, A) JP-A-8-219360 (JP, A) JP-A-8-210568 (JP, A) JP-A-8-177833 (JP , A) JP-A-9-170685 (JP, A) Actually open 57-143472 (JP, U) Actually open 2-107893 (JP, U) Actually open 4-99253 (JP, U) Actually open 58-144180 (JP, U) Sugu 50-3295 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16L 15/00-15/04 F16B 33/02 F16L 47 / 00-47/06

Claims (4)

(57) [Claims] 1. An outer portion is formed of a screw thread portion having a length of about 1/3 from the tip of the entire screw thread portion, an inner portion substantially corresponds to the length of the whole screw thread portion, and an inner diameter thereof is a synthetic resin male screw. A high-strength male thread reinforcing member consisting of a cylindrical body equal to the inner diameter of the joint is attached to the part of the tip portion of the synthetic resin male threaded joint where a notch having the same shape as the male thread reinforcing member is formed, and integrated into an external male thread. It is a joint part, the inside consists of a screw thread part with a length of about 1/3 from the tip of the whole screw thread part, the outside is approximately equivalent to the length of the whole screw thread part, and its outer diameter is a synthetic resin female screw A high-strength female thread reinforcing member made of a cylindrical body smaller than the outer diameter of the joint tip portion is attached to a portion of the tip portion of the female thread of the synthetic resin screw joint, in which a notch having the same shape as the female thread reinforcing member is formed, A threaded joint for synthetic resin piping, etc., characterized by being integrated into a female threaded portion. 2. The threaded joint for a synthetic resin pipe or the like according to claim 1, wherein the high-strength male and female screw reinforcing members are made of metal such as copper-tin alloy. 3. The threaded joint for a synthetic resin pipe or the like according to claim 1, wherein the high-strength male and female screw reinforcing members are formed of a fine ceramic material. 4. The threaded joint for a synthetic resin pipe or the like according to claim 1, wherein the high-strength male and female screw reinforcing members are made of a super engineering plastic material.