JP2012250525A - Method of manufacturing joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a joint, by which after a seal member is fitted to an inner cylinder part, the seal member can be visually recognized from the outside, thereby preventing the fitting of the seal member from being forgotten.SOLUTION: A molding die 30 includes: a pair of split dies 31 molding an outer peripheral surface of a joint body 13; bushes 41 penetrated by the split dies 31 and molding fitting grooves of the inner cylinder part; and slide cores 33, 38 molding a flow passage of the inside of an insert space and the inner cylinder part. The molding die 30 is mold-clamped and the molten resin is injected into a cavity formed in the molding die to be molded. Thus, the inner cylinder part and an outer cylinder part forming the insert space, into which a resin pipe is inserted, in the joint body 13 are integrally formed, the fitting grooves located on the inner end side from an outer end part are provided on the outer peripheral surface of the inner cylinder part, and the joint can be manufactured which includes a pair of visual windows for visually recognizing the fitting of the seal member from the outside in an opposed position of the outer cylinder part.

Description

  The present invention relates to a method of manufacturing a joint used in, for example, a water supply system or a hot water supply system piping system, and more specifically, an outer cylinder part and an inner cylinder part that form a pipe insertion space and a joint body are integrally configured. It is related with the manufacturing method of the joint which can visually recognize mounting | wearing of the sealing member assembled | attached to the outer peripheral surface of an inner cylinder part.

  Conventionally, in a joint used in a water supply system or a hot water supply system piping system, a seal member (packing, O-ring, seal ring, etc.) is mounted between the pipe inserted into the joint body and the joint body, and is watertight. Is held. As a method for maintaining such water tightness, there are a so-called outer diameter sealing method for sealing the outer peripheral side of the pipe and a so-called inner diameter sealing method for sealing the inner peripheral side of the pipe. In the case of the outer diameter seal method, foreign matter and scratches are present on the outer peripheral surface of the pipe that is normally stored in an exposed state, and water leakage occurs when the pipe is connected to the joint. There is. On the other hand, in the case of the inner diameter sealing method, there is no such drawback because the inner peripheral surface of the pipe is sealed. In this inner diameter seal type joint, a pipe insertion space is formed between the outer cylinder part and the inner cylinder part, and the seal member is fitted in a fitting groove recessed in the outer peripheral surface of the inner cylinder part. It is worn.

  This type of inner diameter seal type pipe joint is disclosed in Patent Document 1. The pipe joint is composed of a joint body that constitutes the entire flow path and an outer skin that covers the joint body. The joint body is molded by an injection molding method, and the obtained joint body is inserted into a mold, and a skin resin is injected to form a skin on the joint body. That is, in this pipe joint, the joint main body and the outer skin are formed separately, and after the joint main body is molded, the outer skin must be molded on the outer periphery by an insert molding method. For this reason, there existed a fault that the structure of a pipe joint was complicated and the manufacture became complicated. Accordingly, there is a demand for a joint that has an inner tube portion and an outer tube portion that are formed integrally with the joint body, has a simple structure, and can be easily manufactured.

  A pipe joint described in Patent Document 2 is known as such a joint. That is, this pipe joint is integrally formed with a joint base provided with an inner cylinder part inserted into the inner periphery of the pipe and an outer cylinder part covering the inner cylinder part, and the inner cylinder part has a water stop function as a seal member. An O-ring and an oxygen-impermeable O-ring are provided in parallel. Further, a cap for preventing the pipe from coming off is attached to the joint base.

JP 2005-233363 A JP 2008-95899 A

  By the way, in the joint in which the inner cylinder part and the outer cylinder part are formed integrally with the joint body, after the seal member is assembled to the inner cylinder part, the outer cylinder part exists on the outer periphery thereof. It is not possible to visually check the wearing of. In the joint of the conventional configuration described in Patent Document 2, after the water-stopping O-ring and the oxygen-impermeable O-ring as the sealing member are attached to the inner tube portion, the water stop from the outside due to the presence of the outer tube portion. It is difficult to visually recognize the O-ring and the oxygen-impermeable O-ring. For this reason, there is a possibility that forgetting to attach these seal members to the inner cylinder portion. In this case, there is a problem that water leaks from the joint when the pipe is connected to the joint and water is passed.

  Accordingly, an object of the present invention is to provide a method for manufacturing a joint that can visually recognize the seal member from the outside after the seal member is mounted on the inner cylinder portion, and can prevent forgetting to install the seal member. There is to do.

  In order to achieve the above object, the joint of the invention according to claim 1 is formed by integrally forming an inner cylinder part and an outer cylinder part forming an insertion space into which a pipe is inserted into the joint body, and the inner cylinder part. The outer peripheral surface of the outer cylinder portion is provided with a fitting groove so as to be located on the inner end side with respect to the outer end portion of the outer cylinder portion, and a seal that keeps water tightly between the pipe inserted into the insertion space and the inner cylinder portion A pair of split dies for fitting a member and forming a peripheral window of the joint body, wherein the outer cylinder portion is provided with a visual recognition window for visually confirming the mounting of the seal member from the outside. A molding die comprising: a nest that penetrates the split mold to form a fitting groove of the inner cylinder part; and a slide core that molds the insertion space and a flow path inside the inner cylinder part. The mold is clamped, and a molten resin is injected into a cavity formed in the mold for molding. To.

  The joint according to claim 2 is the invention according to claim 1, wherein the viewing windows are a pair of through holes provided at opposing positions, and the nesting is constituted by a pair of nesting molds, and the end of each nesting mold The portion is formed in a semi-cylindrical shape, provided with a fitting groove forming protrusion, and is configured to form a fitting groove on the outer peripheral surface of the inner cylinder portion.

According to the present invention, the following effects can be exhibited.
In the joint of the present invention, the joint body is integrally formed with an inner cylinder part and an outer cylinder part that form an insertion space into which a pipe is inserted. A fitting groove is provided on the outer peripheral surface of the inner cylinder portion so as to be located on the inner end side with respect to the outer end portion of the outer cylinder portion, and a gap between the pipe inserted into the insertion space and the inner cylinder portion is provided. A seal member that holds water tightly is fitted, and a visual recognition window is opened in the outer cylinder portion. For this reason, after fitting the seal member in the fitting groove of the inner cylinder part, the seal member fitted in the fitting groove of the inner cylinder part can be visually observed from the viewing window of the outer cylinder part. The installation can be confirmed.

Therefore, according to the joint of the present invention, the seal member can be visually recognized from the outside after the seal member is mounted on the inner cylinder portion, and forgetting to install the seal member can be prevented.
Then, a molding die including a pair of split molds for molding the outer peripheral surface of the joint body, a nest for molding the fitting groove of the inner cylinder portion, and a slide core for molding the insertion space and the flow path is molded. Fastening can be performed by injecting molten resin into the cavity. For this reason, the joint with which the inner cylinder part and the outer cylinder part were integrally formed can be easily manufactured by one shaping | molding.

The disassembled perspective view which shows the coupling in embodiment of this invention. The perspective view which shows a coupling. Sectional drawing which shows a coupling. Sectional drawing in the 4-4 line | wire of FIG. The front view which shows the state which attaches a sealing member to the fitting groove | channel of an inner cylinder part, and can be visually recognized from the visual recognition window of an outer cylinder part. The disassembled perspective view which shows the metal mold | die for a coupling. The front view which shows the state which inserted the slide core for insertion space formation, and the slide core for flow path formation in the split type | mold of the shaping | molding metal mold | die of a coupling. (A) is sectional drawing which shows the state which clamped the division | segmentation mold | die of the fixed side of the shaping | molding metal mold | die of a coupling, and the division | segmentation mold | die of a movable side, (b) is a slide core for insertion space formation from the (a) state. Sectional drawing which shows the state inserted. (A) is sectional drawing which shows the state which inserted the slide core for flow-path formation from the state of FIG.8 (b), (b) shows the state which inserted the nest | insert for fitting groove formation from the state of (a). Sectional drawing. Sectional drawing which shows the state which injected the molten resin to the cavity of the metal mold | die for shaping | molding. Sectional drawing which shows the coupling of another example of this invention. Sectional drawing in the 12-12 line | wire of FIG.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 2, the joint 10 is provided with a cylindrical pipe connecting portion 12 to which a resin pipe 11 is connected in three directions, and contains rubber such as polyphenylene sulfide resin (PPS) mixed with rubber. The joint body 13 is made of a synthetic resin. The resin pipe 11 is formed of a synthetic resin such as polyolefin (crosslinked polyethylene, polybutene, etc.). Since the pipe connection parts 12 have the same configuration, only one pipe connection part 12 will be described.

  As shown in FIGS. 1 and 3, the joint body 13 is integrally formed with an inner cylinder portion 15 and an outer cylinder portion 16 that form an insertion space 14 into which the resin pipe 11 is inserted. A pair of fitting grooves 17 are juxtaposed on the outer peripheral surface of the inner cylinder portion 15, and seal members 18 made of ethylene-propylene-diene copolymer rubber (EPDM) are fitted into these fitting grooves 17, respectively. . The seal member 18 is configured such that when the resin pipe 11 is inserted into the insertion space 14, the space between the inner peripheral surface of the resin pipe 11 and the outer peripheral surface of the inner cylindrical portion 15 is kept watertight. The pair of fitting grooves 17 are provided so as to be located on the inner end side with respect to the outer end portion of the outer cylinder portion 16 so that the length of the joint body 13 can be designed to be short. The inner space of the inner cylinder portion 15 is a flow path 19 through which a fluid such as water flows.

  A cylindrical spacer 20 is inserted into the insertion space 14. When the resin pipe 11 is inserted into the insertion space 14, the spacer 20 comes into close contact with the outer peripheral surface of the resin pipe 11. The spacer 20 is formed of a transparent resin such as a polyamide resin so that the inside can be seen through. The spacer 20 can also prevent dust from entering the insertion space 14.

  A retaining mechanism 21 for retaining the resin pipe 11 inserted into the insertion space 14 is provided on the outer end side of the spacer 20. The retaining ring 22 that constitutes the retaining mechanism 21 is made of a metal such as stainless steel, and a retaining piece 22a is formed on the inner periphery of the retaining ring 22 in an oblique direction. The resin pipe 11 is prevented from coming off by biting into the outer peripheral portion of the resin pipe 11 inserted into the insertion space 14. The retaining ring 22 is sandwiched between a PPS cap 23 and a pressing ring 24 made of polyacetal resin (POM) that covers the outer cylinder portion 16. The cap 23 is attached to the outer cylinder portion 16 by the engagement recess 23 a on the inner peripheral surface thereof being engaged with the engagement protrusion 16 a of the outer cylinder portion 16. By forming the cap 23 with a transparent resin, the seal member 18 can be visually recognized through the cap 23, a viewing window 25 described later, and the spacer 20.

  A split ring 26 made of PPS is interposed between the retaining ring 22 and the cap 23 so as to keep the inclination angle of the retaining piece 22a. The retaining ring 21 for the resin pipe 11 is constituted by the retaining ring 22, the holding ring 24, the cap 23, the split ring 26, and the like.

  In the insertion space 14, an insertion guide 27 made of polypropylene resin (PP) that is pressed against the distal end surface of the resin pipe 11 and guides insertion of the resin pipe 11 is disposed. The insertion guide 27 is formed in a C-ring shape and is configured to be able to expand and contract. A cap cover 28 made of stainless steel is attached to the outer peripheral surface of the cap 23, and holds the cap 23 against the outer cylinder portion 16.

  As shown in FIGS. 4 and 5, a pair of viewing windows 25 for viewing the seal member 18 fitted in the fitting groove 17 of the inner cylinder part 15 from the outside are opposed to the outer cylinder part 16 at 180 °. Is provided. The viewing window 25 is configured by a through hole so that the presence or absence of the seal member 18 fitted in the fitting groove 17 of the inner cylinder portion 15 can be confirmed from the outside of the outer cylinder portion 16. Further, a confirmation hole 29 for confirming the presence or absence of the resin pipe 11 to be inserted into the insertion space 14 is formed through the inner end portion of the outer cylinder portion 16.

Next, a molding die for manufacturing the joint 10 configured as described above will be described.
As shown in FIG. 6, the pair of split molds 31 constituting the molding die 30 are configured such that the fixed split mold 31a and the movable split mold 31b are arranged to face each other. Each split mold 31a, 31b is provided with an outer peripheral surface forming recess 32 that forms the outer peripheral surface of the outer cylinder portion 16 extending in three directions. Then, the outer peripheral surface of the outer cylinder portion 16 of the joint body 13 can be molded by clamping the pair of split dies 31 a and 31 b and injecting molten resin into the outer peripheral surface forming recess 32.

  The insertion space forming slide core 33 is configured by connecting a cylindrical body 35 to a base 34 having a rectangular parallelepiped shape on the base end side. A circular hole 36 extending in the axial direction of the cylindrical body 35 is formed through the center of the base 34, and the circular hole 36 communicates with a space in the cylindrical body 35. A pair of elongated holes 37 are formed through the cylindrical body 35 so as to face each other at 180 degrees.

  The flow path forming slide core 38 is configured such that a columnar body 40 is connected from a central portion of the base 39 on the base end side so as to extend in a direction orthogonal to the base 39. The cylindrical body 40 of the flow path forming slide core 38 is clamped so as to extend into the cylindrical body 35 through the circular hole 36 of the base 34 of the insertion space forming slide core 33.

  The insert 41 for forming the fitting groove 17 is configured so that a pair of divided insert molds 41a and 41b are arranged to face each other. Each of the nesting dies 41 a and 41 b is configured such that a protruding die 44 for forming the fitting groove 17 is provided on one surface of a base 43 having a square disk shape. Two protrusion groove-forming protrusions 45 having a semicircular arc shape are formed at the tip of the protruding mold 44 at regular intervals. A protrusion 46 for forming the confirmation hole 29 is formed adjacent to the protrusion 44 so as to protrude in parallel with the protrusion 44.

  The projecting mold 44 and the projecting mold 46 of the insert molds 41a and 41b are inserted into the insertion hole 47 and the insertion hole 48 formed in the fixed and movable split molds 31a and 31b, and the outer peripheral surface forming recess 32 is inserted. It comes to face inside. At this time, the projecting molds 44 forming the semicircular arc shape of the nesting molds 41 a and 41 b are abutted to form a cylindrical shape, and the annular fitting groove 17 is formed on the outer peripheral surface of the inner cylinder portion 15. Has been.

Next, a method for manufacturing the joint 10 using the molding die 30 configured as described above will be described.
As shown in FIG. 8 (a), the joint body 13 is first formed in both split molds 31a and 31b by first moving the movable split mold 31b toward the fixed split mold 31a and clamping the mold. The cavity 49 is formed, and the outer peripheral surface of the outer cylinder part 16 can be formed. Subsequently, as shown in FIG. 8B, the insertion space 14 between the outer cylinder portion 16 and the inner cylinder portion 15 is formed by sliding the insertion space forming slide core 33 and clamping the mold. It becomes possible. Next, as shown in FIG. 9A, the flow path forming slide core 38 is inserted into the circular hole 36 of the insertion space forming slide core 33 and clamped, so that the flow inside the inner cylinder portion 15 is increased. The path 19 can be formed. At this time, as shown in FIG. 7, the elongated hole 37 of the insertion space forming slide core 33 is inserted to a position where the fitting groove 17 of the inner cylinder portion 15 is formed.

  Thereafter, as shown in FIG. 9B, the protruding mold 44 and the protruding mold 46 of the insert 41 for forming the fitting groove 17 are inserted into the insertion hole 47 and the insertion hole 48 of the divided molds 31a and 31b. Clamp the mold. As shown in FIG. 10, in this way, each of the divided dies 31a and 31b, the insertion space forming slide core 33, the flow path forming slide core 38, and the nesting dies 41a and 41b were formed and clamped. By injecting a melt of PPS from the gate 57 into the cavity 49, the joint body 13 can be molded.

  Then, after the formed joint body 13 is cooled, the insert molds 41a and 41b are extracted, the flow path forming slide core 38 is subsequently extracted, then the insertion space forming slide core 33 is extracted, and finally each The joint body 13 can be taken out by dividing the split dies 31a and 31b.

Next, the effect | action is demonstrated about the coupling 10 comprised as mentioned above.
Now, an inner cylinder part 15 and an outer cylinder part 16 that form the insertion space 14 of the resin pipe 11 are integrally formed in the joint body 13 in the joint body 13 by an injection molding method. For this reason, the connection part of the inner cylinder part 15 and the outer cylinder part 16 is lose | eliminated, and while the length of the joint 10 whole can be designed by that much, the strength fall by a connection part can be avoided and the intensity | strength of the joint 10 can be avoided. Can be increased. Further, a visual recognition window 25 is opened in the outer cylinder portion 16 of the joint body 13. Therefore, after the sealing member 18 is fitted into the fitting groove 17 of the inner cylinder part 15, the sealing member 18 fitted into the fitting groove 17 of the inner cylinder part 15 is visually observed from the viewing window 25 of the outer cylinder part 16. be able to. Accordingly, it is possible to easily and quickly confirm whether or not the seal member 18 is attached.

  Thereafter, when the resin pipe 11 is inserted into the insertion space 14 of the joint 10, the inner end portion of the resin pipe 11 is guided and inserted by the insertion guide 27, and is retained by the retaining mechanism 21. In this way, as shown in FIGS. 2 and 3, the three resin pipes 11 are connected to the three-way pipe connection portions 12 of the joint 10.

The effects exhibited by the above embodiment will be described collectively below.
(1) In the joint 10 of this embodiment, the inner cylinder part 15 and the outer cylinder part 16 which form the insertion space 14 of the resin pipe 11 in the joint main body 13 are integrally formed. Further, a fitting groove 17 is provided on the outer peripheral surface of the inner cylinder portion 15 to fit a seal member 18, and a viewing window 25 is opened in the outer cylinder portion 16. For this reason, when the seal member 18 is fitted in the fitting groove 17 of the inner cylinder portion 15, the seal member 18 can be visually observed from the viewing window 25 of the outer cylinder portion 16, and the installation of the seal member 18 is confirmed. Can do.

Therefore, according to the joint 10 of this embodiment, after the seal member 18 is attached to the inner cylinder portion 15, the seal member 18 can be visually recognized from the outside, and forgetting to attach the seal member 18 can be prevented. There is an effect that water leakage in the joint 10 can be prevented.
(2) A pair of viewing windows 25 of the outer cylinder portion 16 are provided at opposing positions. Therefore, the structure of the insert 41 for forming the fitting groove 17 for forming the fitting groove 17 of the inner cylinder portion 15 can be simplified, and the molding can be easily performed.
(3) Since the visual recognition window 25 is a through-hole, the mechanical strength of the outer cylindrical portion 16 can be favorably maintained as compared with the notch.
(4) The fitting groove 17 is provided so as to be located on the inner end side with respect to the outer end portion of the outer cylinder portion 16. Therefore, the overall dimensions of the joint 10 can be designed to be short, and the pressure loss can be reduced even with the joint 10 in which the diameter of the flow path 19 is small by the inner diameter sealing method.
(5) When manufacturing the joint 10, a pair of split dies 31 a and 31 b that mold the outer peripheral surface of the joint body 13, a nest 41 that molds the fitting groove 17 of the inner cylinder portion 15, and an insertion space 14 and the slide cores 33 and 38 for molding the flow path 19 are clamped and the molten resin is injected into the cavity 49. For this reason, the joint 10 in which the inner cylinder part 15 and the outer cylinder part 16 are integrally formed can be easily manufactured by one molding.
(6) The insert 41 is composed of a pair of insert molds 41a and 41b. Ends of the insert molds 41a and 41b are formed in a semi-cylindrical shape and provided with fitting groove forming protrusions 45. The fitting groove 17 is formed on the outer peripheral surface of the cylindrical portion 15. Therefore, the fitting groove 17 of the inner cylinder part 15 can be easily formed with a simple mold configuration, and at the same time, the visual recognition window 25 of the outer cylinder part 16 can be shaped so as to face the fitting groove 17. it can.

In addition, the said embodiment can also be changed and actualized as follows.
As shown in FIG. 11, the joint 10 is provided with the joint body 13 of the above embodiment at one end, the connection adapter 50 is connected to the other end, and a male screw 51 connected to a water faucet (not shown). It can also comprise so that it may provide. That is, at the other end of the joint 10, a connecting adapter 50 having a cylindrical shape is connected to an annular groove 52 that is recessed in the outer peripheral surface of the joint body 13 and a recess 53 of the connecting adapter 50. 54 are connected. An annular groove 55 is formed on the outer peripheral surface of the inner cylinder 50a of the connection adapter 50, and an O-ring 56 is fitted therein, so that the joint body 13 and the connection adapter 50 are kept watertight. As shown in FIG. 12, the outer cylinder portion 16 of the joint body 13 is opened with a visual recognition window 25 for viewing the seal member 18 fitted in the fitting groove 17 of the inner cylinder portion 15 as in the above embodiment. ing.

As the visual recognition window 25, it is possible to configure the outer cylinder portion 16 by a notch that is notched from the outer end side to the inner end side.
-It is also possible to comprise the said joint 10 so that the pipe connection part 12 may become 2 directions, 4 directions, etc.

  The spacer 20 can be omitted. In this case, since the thickness of the cylindrical body 35 of the insertion space forming slide core 33 is reduced, it is necessary to design the cylindrical body 35 to have sufficient mechanical strength.

  A single sealing member 18 is formed by using one fitting groove 17 in the inner cylinder portion 15, or the fitting groove 17 is formed wide to fit the wide sealing member 18 into the fitting groove 17. Or can be configured.

  The joint body 13 or the like can be formed of a synthetic resin (engineering plastic) such as polyacetal (POM), polyphthalamide (PPA), or polyphenylsulfone (PPSU).

As the pipe, in addition to the resin pipe 11, a soft metal pipe such as a copper pipe can be used.
-The retaining mechanism 21 and the cap 23 of the joint 10 can be omitted.

  The joint 10 can be used for connecting a water heating system pipe, a hot water system pipe, a floor heating pipe, a road heating pipe, and the like.

  DESCRIPTION OF SYMBOLS 10 ... Joint, 11 ... Resin pipe, 13 ... Joint main body, 14 ... Insertion space, 15 ... Inner cylinder part, 16 ... Outer cylinder part, 17 ... Insertion groove, 18 ... Seal member, 19 ... Flow path, 25 ... Viewing window, 30 ... molding mold, 31 ... divided mold, 31a ... fixed side divided mold, 31b ... movable side divided mold, 33 ... insertion space forming slide core, 38 ... flow path forming slide core, 41 ... Nesting, 41a, 41b ... Nesting type, 45 ... Projection groove forming protrusion, 49 ... Cavity.

Claims (2)

An inner cylinder part and an outer cylinder part that form an insertion space into which a pipe is inserted are integrally formed in the joint body, and the outer peripheral surface of the inner cylinder part is located closer to the inner end side than the outer end part of the outer cylinder part. A sealing member is provided so that a fitting groove is provided and the pipe inserted into the insertion space and the inner cylinder part are kept watertight, and the outer cylinder part is attached with the sealing member from the outside. A method of manufacturing a joint provided with a visual recognition window for visual recognition,
A pair of split molds for molding the outer peripheral surface of the joint body; a nest that penetrates the split mold to mold the fitting groove of the inner cylinder part; and a flow path inside the insertion space and the inner cylinder part. A method for manufacturing a joint, comprising: clamping a molding die including a slide core to be molded, and injecting molten resin into a cavity formed in the molding die. The viewing windows are through-holes provided at a position facing each other,
The nesting is composed of a pair of nesting molds, and the end of each nesting mold is formed in a semi-cylindrical shape, and provided with a projection for forming a fitting groove, and a fitting groove is formed on the outer peripheral surface of the inner cylinder part. The method for manufacturing a joint according to claim 1, wherein