JP2016141007A - Manufacturing method of pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint manufacturing method capable of smoothly manufacturing a pipe joint having an undercut part without deteriorating productivity.SOLUTION: A header piece 10a composing a header 10 comprises a first connection part 13 having an undercut part 12, a second connection part 15 having an outer screw part 14, and a third connection part 17 having an inner screw part 16. A pipe joint body 11 of the header piece 10a is formed of a resin containing a rubber-like elastic body, the outer screw part 14 is formed of an outer screw insert member 28, and the inner screw part 16 is formed of an inner screw insert member 35. When the header piece 10a is molded, the insert members 28, 35 are arranged in a mold. After a molten resin containing the rubber-like elastic body is injected into the mold to form the pipe joint body 11, a stationary mold is opened, a movable mold is forcibly pulled out from the first connection part 13, and movable molds are pulled out from the second connection part 15 and the third connection part 17.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a pipe joint for forming a pipe joint such as a header piece constituting a header used in a piping system of a water supply system or a hot water supply system by an injection molding method (insert molding method).

  In resin molding, when a molded product having an undercut portion is manufactured by an injection molding method, it is necessary to devise in order to take out the molded product having an undercut portion from the mold after injection molding. Various demolding apparatuses and demolding methods for molded products having such an undercut have been studied.

  This type of demolding apparatus is disclosed in Patent Document 1, for example. That is, the cavity is formed by a fixed mold, a movable mold, and a rotating mold component (core mold), and a demolding device is provided in the movable mold, and is driven to rotate by the motor and the motor. It consists of a rotating body. When the movable mold is opened from the fixed mold after injection molding, the molded product remains on the movable mold side. Next, when the rotating body is rotated by the motor, the core mold rotates, and the molded product is extracted from the core mold.

JP 2012-35533 A

  However, when molding a molded product having an undercut portion with a conventional demolding apparatus, a problem may occur. Specifically, if the core mold is driven to rotate while the molded product is heated, the thread of the molded product may be deformed under the force of the core mold to push the molded product. It was. There is also a method of cooling the molded product after taking out the core mold, and taking out the molded product by rotationally driving the core mold. However, in such a method, the cycle time becomes long, so productivity is increased. There was a problem of significant reduction.

  Then, the place made into the objective of this invention is providing the manufacturing method of the pipe joint which can manufacture the pipe joint which has an undercut part smoothly, without causing the fall of productivity.

  In order to achieve the above object, a method for manufacturing a pipe joint according to the present invention includes a first connection part having an undercut part and a second connection part having a thread part. The pipe joint main body constituting the pipe joint is formed of a resin containing a rubber-like elastic body, the threaded portion is formed of an insert member different from the pipe joint main body, and is fixed when the pipe joint is molded. After placing the insert member in a mold having a molding cavity between the mold and the movable mold, a molten resin containing a rubber-like elastic body is injected from the mold gate into the cavity to mold the pipe joint body. Then, the movable mold is forcibly extracted at the first connection portion, and the movable mold is extracted at the second connection portion to manufacture a pipe joint.

  The pipe joint is a header piece constituting a header. The header piece is formed with a first connection portion and a second connection portion at both ends of a straight pipe, and a third pipe is connected to a branch pipe perpendicular to the straight pipe. It is preferable that a connecting portion is formed.

The resin containing the rubber-like elastic body is preferably an engineering plastic containing a thermoplastic elastomer.
The engineering plastic is preferably a polyphenylene sulfide (PPS) resin.

  The resin forming the insert member is preferably a glass fiber-containing polyphenylene sulfide (PPS) resin or a carbon fiber-containing polyphenylene sulfide (PPS) resin.

  It is preferable that the insert member is provided with a retaining portion that engages with the pipe joint main body to prevent the insert member from coming off and restricts rotation of the insert member in the circumferential direction.

It is preferable that a spiral groove is formed on the inner peripheral surface of the insert member in which the thread portion is an external thread portion.
It is preferable that the insert member forming the third connection portion is disposed to face the gate of the mold.

  According to the method for manufacturing a pipe joint of the present invention, it is possible to smoothly manufacture a pipe joint having an undercut portion without causing a decrease in productivity.

(A) is sectional drawing which decomposes | disassembles and shows three header pieces which comprise the header in 1st Embodiment, (b) is sectional drawing which shows the header which connected the header piece. The expanded sectional view which shows the 1st header piece. The expanded sectional view showing the 2nd header piece. (A) is an expanded sectional view which shows a 3rd header piece, (b) is the partial expanded sectional view which shows an undercut part. The front view which shows the state which connected main piping and branch piping to the header. (A) is sectional drawing which shows an external thread insert member, (b) is a front view which shows an external thread insert member. (A) is sectional drawing which shows an internal thread insert member, (b) is a side view which shows an internal thread insert member, (c) is a front view which shows an internal thread insert member. Sectional drawing which shows the metal mold | die for shape | molding a pipe joint, and decomposes | disassembles and shows the 1st slide type | mold, 2nd slide type | mold and 3rd slide type | mold as a fixed mold | type and a movable mold | type, an external thread insert member, and an internal thread insert member . FIG. 9 is a cross-sectional view showing a state in which the outer screw insert member is mounted on the second slide mold and the inner screw insert member is mounted on the third slide mold in FIG. 8. Sectional drawing which shows the state which injected the molten resin containing a rubber-like elastic body from the gate to a cavity, after forming a cavity by clamping a fixed mold | type and a movable mold | type. FIG. 11 is a cross-sectional view illustrating a state in which the movable mold is extracted after the fixed mold is opened in FIG. 10. Sectional drawing which shows the metal mold | die for shape | molding the pipe joint in 2nd Embodiment, and shows the state which opened the fixed side metal mold | die and the movable side metal mold | die. Sectional drawing which shows the state which injected the molten resin to the cavity after clamping a 3rd slide type | mold while clamping a fixed side metal mold | die and a movable side metal mold | die. FIG. 14 is a cross-sectional view illustrating a state in which the movable mold is opened from the fixed mold and the third slide mold is retracted from the state of FIG. 13. Sectional drawing which shows the state which extrudes an ejector sleeve from the state of FIG. 14, forcibly removes an undercut formation part, and shape | molds an undercut part. The expanded sectional view which shows another example of this invention and shows a cheese joint. The expanded sectional view which shows the further another example of this invention and shows a cheese joint. The expanded sectional view which shows another example of this invention and shows a straight tubular coupling.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS.
As shown in FIG. 1B, the header 10 is configured by connecting three header pieces 10a, 10b, and 10c as pipe joints. As shown in FIG. 1 (a), the first header piece 10a (the right end of FIG. 1 (a)) is connected to the second header piece 10b (the center of FIG. 1 (a)), and the second header A third header piece 10c [left end of FIG. 1A] is connected to the piece 10b. These header pieces 10a, 10b, and 10c will be described in order.

  As shown in FIG. 5, the main pipe 30 is connected to the first header piece 10 a via a union joint 29 and a branch pipe 66 is connected to the first header piece 10 a via a joint 65. The second header piece 10b is coupled to the first header piece 10a and the third header piece 10c, and a branch pipe 66 is connected via a joint 65. The third header piece 10c is coupled to the second header piece 10b, to which the main pipe 26 is connected, and to which a branch pipe 66 is connected via a joint 65. Then, a fluid (water or hot water) flows into the header 10 from the main pipe 26 connected to the third header piece 10c, flows into the main pipe 30 of the first header piece 10a, and branches to each branch pipe 66. It has come to be.

  As shown in FIG. 2, the pipe joint main body 11 constituting the first header piece 10a is formed in a substantially inverted T-shaped cross section, and has a first connecting portion 13 having an undercut portion 12 on the inner peripheral surface, and an outer periphery. It has the 2nd connection part 15 which has the external thread part (male thread part) 14 in the surface, and the 3rd connection part 17 which has the internal thread part (female thread part) 16 in the internal peripheral surface. The third connection portion 17 is for connecting a branch pipe 66 that branches the fluid flowing between the first connection portion 13 and the second connection portion 15. The pipe joint body 11 is formed of a resin containing a rubber-like elastic body and exhibits rubber-like elasticity.

  As the rubber-like elastic body, a thermoplastic elastomer, rubber or the like is preferably used. Examples of the thermoplastic elastomer include polyolefin-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, and the like. Examples of rubber include ethylene-propylene-diene copolymer rubber (EPDM), ethylene-propylene copolymer rubber (EPM), butyl rubber (IIR), nitrile rubber (NR), and styrene-butadiene copolymer rubber (SBR). . One or more of these rubber-like elastic bodies are appropriately selected and used depending on the purpose of use.

  The resin (synthetic resin or natural resin) is preferably an engineering plastic from the viewpoint of mechanical strength, heat resistance, and the like. Examples of the engineering plastic include polyphenylene sulfide (PPS) resin, polyamide (nylon) resin, polyacetal resin, polyester resin, polycarbonate resin, polysulfone resin, and polyimide resin. Of these engineering plastics, PPS resins are preferred because of their excellent physical properties such as hot water resistance.

  The content of the rubber-like elastic body in the resin containing the rubber-like elastic body is preferably 10 to 40% by mass. When the content of the rubber-like elastic body is less than 10% by mass, the elasticity of the formed pipe joint body 11 is insufficient, and the first slide die 54 described later is difficult to be pulled out from the undercut portion 12, and the undercut portion 12 is difficult to form, and as a result, the undercut portion 12 is damaged. On the other hand, when it is more than 40% by mass, the undercut portion 12 can be easily molded, but this is not preferable because the mechanical properties and the like of the obtained pipe joint body 11 tend to be lowered.

  The first connecting portion 13 is formed in a cylindrical shape, and the undercut portion 12 is formed on the inner peripheral surface thereof by an annular groove formed in a circular arc shape in cross section. The undercut portion 12 becomes an obstacle when pulling out a first slide mold 54 to be described later for forming the first connection portion 13 outward in the axial direction of the first connection portion 13, Since the pipe joint main body 11 is formed of a resin containing a rubber-like elastic body, it is possible to pull out the first slide die 54 while suppressing damage to the undercut portion 12.

  The second connection portion 15 is configured such that an external thread insert member 28 separate from the pipe joint body 11 is provided on the outer periphery of the pipe joint body 11. The external screw insert member 28 is made of a metal such as bronze or brass or a resin having a melting point (freezing point) higher than that of the resin containing the rubber-like elastic body, and deformation due to heat of the molten resin is prevented during insert molding. As such a resin, a PPS resin containing glass fiber, a PPS resin containing carbon fiber, or the like is preferably used. Since the melting point of glass fiber or carbon fiber is higher than the melting point of PPS resin, the melting point of PPS resin containing glass fiber or PPS resin containing carbon fiber is higher than the melting point of PPS resin. The content of glass fiber or carbon fiber is usually about 20 to 40% by mass.

  As shown in FIGS. 6A and 6B, a spiral groove 64 is continuously formed on the inner peripheral surface of the outer screw insert member 28 over the entire inner peripheral surface. As shown in FIG. 2, by this spiral groove 64, the thin cylindrical portion 11a of the pipe joint main body 11 formed on the inner peripheral portion of the external thread insert member 28 is extracted by extracting the second slide die 55 described later after insert molding. The possibility of receiving damage such as peeling can be suppressed.

  As shown in FIGS. 2 and 6 (a) and 6 (b), a retaining portion 34 formed by a pair of annular protrusions is provided on the outer periphery of the inner end side of the outer screw insert member 28, and the pipe joint body. 11, the external thread insert member 28 is prevented from coming off. The outer peripheral surfaces of these retaining portions 34 are knurled to form an uneven portion (not shown), and the rotation of the outer screw insert member 28 in the circumferential direction is restricted. An outer thread portion 14 is formed on the outer peripheral surface of the outer end portion of the outer thread insert member 28, and the union joint 29 is screwed to the outer thread portion 14.

  Next, the third connecting portion 17 will be described. As shown in FIG. 2 and FIGS. 7A to 7C, the third connection portion 17 is provided with an inner thread insert member 35 that is separate from the pipe joint body 11 on the inner periphery of the pipe joint body 11. Configured. On the outer peripheral surface of the inner thread insert member 35, a retaining portion 34 is provided by four protrusions formed in a columnar shape at intervals of 90 degrees in the circumferential direction, and is engaged with the engaging recess 63 of the pipe joint body 11. Accordingly, the inner screw insert member 35 is prevented from coming off, and the rotation of the inner screw insert member 35 in the circumferential direction is restricted. The inner thread portion 16 is formed on the inner peripheral surface of the inner thread insert member 35, and the male thread 37 of the joint 65 is screwed together.

Next, the second header piece 10b will be described.
As shown in FIG. 3, the first connecting portion 13 and the third connecting portion 17 of the second header piece 10b are connected to the first connecting portion 13 and the third connecting portion 17 of the first header piece 10a. It is the same configuration. The second connection portion 15 is formed in a cylindrical shape, and an annular recess 67 is formed on the outer peripheral surface of the inner end side, and a locking ring 68 configured to be extendable is mounted. A pair of fitting grooves 69 are formed on the outer peripheral surface of the second connecting portion 15, and a seal ring 70 is fitted in each of the fitting grooves 69.

  And when the 2nd header piece 10b is connected with the 1st header piece 10a, the latching ring 68 of the 2nd connection part 15 of the 2nd header piece 10b is the 1st connection part 13 of the 1st header piece 10a. Engaged with the undercut portion 12.

Next, the third header piece 10c will be described.
As shown in FIGS. 4A and 4B, the second connection portion 15 and the third connection portion 17 of the third header piece 10c are connected to the second connection portion 15 and the second connection portion 15 of the second header piece 10b. 3 has the same configuration as that of the third connecting portion 17. The first connection portion 13 is formed in a cylindrical shape, and an undercut portion 12 is formed on the inner peripheral portion of the tip, and a pair of locking projections 74 are formed on the outer peripheral surface. A cap 25 is fitted on the first connecting portion 13, and a retaining ring 27 for retaining the main pipe 26 is interposed between the inner peripheral portion of the cap 25 and the first connecting portion 13. Yes. A pair of locking recesses 71 are formed on the inner peripheral surface of the inner end portion of the cap 25, and the locking projections 74 of the first connection portion 13 are locked. A stainless steel cover body 44 is fitted on the outer periphery of the base end portion of the cap 25 to restrict the opening of the cap 25.

  And when the 3rd header piece 10c is connected with the 2nd header piece 10b, the latching ring 68 of the 2nd connection part 15 of the 3rd header piece 10c is the 1st connection part 13 of the 2nd header piece 10b. Engaged with the undercut portion 12. In addition, the main pipe 26 is inserted into the first connection portion 13 and is configured to be held so as not to come off.

  A manufacturing apparatus for forming the header pieces 10a, 10b, and 10c configured as described above will be described. In addition, since the manufacturing apparatus of the 1st header piece 10a, the 2nd header piece 10b, and the 3rd header piece 10c as a pipe joint is similar, the manufacturing apparatus of the 1st header piece 10a is demonstrated as a representative.

  As shown in FIGS. 8 and 10, a mold 50 for molding the first header piece 10a includes a fixed mold (outer mold) 51 as a fixed mold and a movable mold (inner mold) as a movable mold. 52 and a molding cavity 53 formed between the fixed mold 51 and the movable mold 52. The movable mold 52 includes a first slide mold 54 that molds the first connection portion 13, a second slide mold 55 that molds the second connection portion 15, and a third slide mold 56 that molds the third connection portion 17. It is comprised by.

  The fixed mold 51 is configured to mold the entire first connection portion 13, second connection portion 15, and third connection portion 17, and is divided into two. The fixed mold 51 and the movable mold 52 are clamped to form the cavity 53 for resin molding between the fixed mold 51 and the movable mold 52. A gate 57 for injecting molten resin is provided on the dividing surfaces of the fixed mold 51 and the movable mold 52. An undercut forming portion 60 for forming the undercut portion 12 is formed on the outer periphery of the first slide die 54 so as to project in an annular shape.

  The external thread insert member 28 having the external thread portion 14 and the internal thread insert member 35 having the internal thread portion 16 are formed separately from the pipe joint body 11 in advance. The second slide mold 55 and the third slide mold 56 are respectively provided with an external screw insert support portion 58 and an internal screw insert support portion 59 for supporting the external screw insert member 28 and the internal screw insert member 35, respectively. The outer screw insert support portion 58 is formed by an annular recess recessed in the front end surface of the second slide die 55, and the inner screw insert support portion 59 is formed by a step portion of the third slide die 56 having a cylindrical shape. ing.

  The third slide die 56 and the inner screw insert member 35 are disposed so as to face the gate 57, and the inner screw insert member 35 is moved to the inner screw insert support portion 59 by the pressure of the molten resin injected from the gate 57. Pressed. With respect to the arrangement of the inner screw insert member 35, the inner screw insert member 35 is inserted into the inner screw insert support portion 59 having the stepped shape of the third slide die 56 and is arranged by a simple procedure. The insert member 35 can be accurately arranged. The second slide die 55 is disposed below the fixed die 51 so that the external screw insert support portion 58 is opened upward, and the external screw insert member 28 is positioned on the external screw insert support portion 58 by its own weight. It has become.

Next, the manufacturing method of the first header piece 10a configured as described above will be described together with the operation.
As shown in FIGS. 8 and 9, when manufacturing the first header piece 10 a, first, the outer screw insert member 28 is disposed on the outer screw insert support portion 58 of the second slide die 55, and the third slide die 56. The inner screw insert member 35 is disposed on the inner screw insert support portion 59. In this case, the outer thread insert member 28 and the inner thread insert member 35 are formed separately from the pipe joint main body 11 in advance, and the melting point of the resin forming both the insert members 28 and 35 forms the pipe joint main body 11. It is higher than the melting point of the resin. For this reason, the external thread portion 14 of the external thread insert member 28 and the internal thread portion 16 of the internal thread insert member 35 are formed without crushing the thread groove when the pipe joint body 11 is molded.

  Subsequently, as shown in FIG. 10, the movable mold 52 is inserted into the fixed mold 51 and clamped, and a cavity 53 is formed between the fixed mold 51 and the movable mold 52. Next, the pipe joint main body 11 can be molded by injecting a molten resin containing a rubber-like elastic body into the cavity 53 from the gate 57 and performing insert molding according to a conventional method.

  As shown in FIG. 11, after insert molding, the fixed mold 51 divided into two is opened. Thereafter, as shown by a two-dot chain line in FIG. 11, the first slide die 54 is extracted from the first connection portion 13 of the pipe joint body 11. At this time, since the pipe joint body 11 is formed of a resin containing a rubber-like elastic body, the first connection portion 13 is elastically expanded by pulling the first slide die 54 outward in the axial direction. The first slide die 54 can be forcibly removed without opening and damaging the undercut portion 12 by expanding the diameter of the undercut portion 12.

  Similarly, as shown by the two-dot chain line in FIG. 11, the second slide mold 55 and the third slide mold 56 are not provided with the undercut portion 12 in the second connection portion 15 and the third connection portion 17. For this reason, the second slide mold 55 and the third slide mold 56 are pulled out from the pipe body 11 without resistance by pulling the second slide mold 55 and the third slide mold 56 in the outward direction of the respective axes to release the mold. can do. Thus, the 1st header piece 10a which has the 1st connection part 13, the 2nd connection part 15, and the 3rd connection part 17 can be manufactured by simple operation.

The effects exhibited by the above first embodiment will be described collectively below.
(1) In the manufacturing method of the first header piece 10a in the first embodiment, the pipe joint main body 11 is formed of a resin containing a rubber-like elastic body, and the screw portions 14 and 16 are inserts different from the pipe joint main body 11. The members 28 and 35 are used. Then, when the first header piece 10 a is molded, the insert members 28 and 35 are arranged in the mold 50, and then the molten resin containing a rubber-like elastic body is injected into the cavity 53 to mold the pipe joint body 11. Next, the fixed die 51 is opened, the first slide die 54 is forcibly removed from the first connection portion 13, and the second slide die 55 and the second connection die 17 are removed from the second connection portion 15 and the third connection portion 17. By extracting the three-slide mold 56, the first header piece 10a is manufactured.

  For this reason, the pipe joint body 11 can be quickly formed by a conventional insert molding method, and after the insert molding, the first connection portion 13, the second connection portion 15, and the third connection portion 17 can be easily released. Can be advanced by simple operation.

  Therefore, according to the manufacturing method of the 1st header piece 10a of this embodiment, the 1st header piece 10a which has the undercut part 12 can be manufactured smoothly, without causing the fall of productivity.

  (2) The resin containing a rubber-like elastic body is an engineering plastic containing a thermoplastic elastomer. In this case, the first header piece 10a can exhibit characteristics such as mechanical strength and heat resistance. Further, the engineering plastic is polyphenylene sulfide (PPS) resin. In this case, the 1st header piece 10a can exhibit especially a heat-resistant water characteristic.

  (3) The resin forming the insert members 28 and 35 is a polyphenylene sulfide (PPS) resin containing glass fibers or a polyphenylene sulfide (PPS) resin containing carbon fibers. Therefore, the insert members 28 and 35 show high heat resistance, and the insert molding of the first header piece 10a can be performed in a stable state.

  (4) The insert members 28 and 35 are provided with a retaining portion 34 that engages with the engaging recess 63 of the pipe joint body 11 to prevent the insert members 28 and 35 from slipping out. For this reason, the insert members 28 and 35 can be firmly fixed to the pipe joint main body 11 by restricting rotation in the circumferential direction.

  (5) A spiral groove 64 is formed on the inner peripheral surface of the outer screw insert member 28. Therefore, when extracting the 2nd slide type | mold 55 after insert molding of the 1st header piece 10a, the damage with respect to the cylinder part 11a of the pipe fitting main body 11 shape | molded can be suppressed.

  (6) The inner screw insert member 35 that forms the third connecting portion 17 is disposed to face the gate 57, and the outer screw insert member 28 that forms the second connecting portion 15 is an outer screw insert support portion. It is inserted and supported with respect to 58 from below. Therefore, the inner screw insert member 35 can be stably supported on the inner screw insert support portion 59 by the pressure of the molten resin injected from the gate 57, and the outer screw insert member 28 is supported on the outer screw insert support portion 58 by its own weight. It can be easily supported.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, parts different from the first embodiment will be mainly described.

  As shown in FIG. 12, the mold 50 includes a fixed mold 81 as a fixed mold and a movable mold 82 as a movable mold. The first slide mold 54 that forms the first connection portion 13 having the undercut portion 12 and the third slide mold 56 that forms the third connection portion 17 in the first embodiment are provided in the movable mold 82. The second slide mold 55 that forms the second connection portion 15 is provided in the fixed mold 81. That is, the first slide mold 54 is formed integrally with the movable mold 82 to become a movable integral mold 83 as a movable mold, and is formed so that the tip portion projects from the accommodation hole 84 of the movable mold 82. ing. An ejector sleeve 85 is disposed on the outer periphery of the movable-side integrated mold 83, and is configured to extract the molded pipe joint body 11.

  The second slide die 55 is formed so as to protrude from the fixed die 81 to become a fixed integrated die 86, and the insert member 28 is fitted on the outer periphery thereof. The third slide mold 56 as a movable mold is formed so as to protrude from the movable mold 82, and is configured to be movable in a direction orthogonal to the moving direction of the movable mold 82. The insert member 35 is fitted on the outer periphery thereof. It is. In addition, an outer slide core 87 for forming the outer peripheral portion of the pipe joint body 11 is disposed at a portion of the movable side die 82 facing the fixed side die 81 so that it can slide in a direction orthogonal to the paper surface of FIG. ing. A support member 88 that supports the outer slide core 87 protrudes from the end of the fixed mold 81 corresponding to the outer slide core 87.

  Subsequently, as shown in FIG. 13, the pipe joint body 11 can be formed by clamping the movable mold 82 to the fixed mold 81 and injecting molten resin into the cavity 53 in this state.

  Next, as shown in FIG. 14, by separating the movable side mold 82 from the fixed side mold 81, the pipe joint body 11 is extracted from the fixed side integrated mold 86, and the third slide mold 56 is moved to the position shown in FIG. By sliding downward, the third slide die 56 is extracted from the inside of the pipe joint main body 11 and the insert member 35.

  After that, as shown in FIG. 15, the ejector sleeve 85 is pushed out in the direction of the fixed die 81 (left direction in FIG. 15), whereby the pipe joint body 11 is extracted from the movable side integrated die 83, and the undercut molding portion 60 is obtained. Is forcibly removed, and the undercut portion 12 is formed.

  As described above, in the second embodiment, the movable-side integrated mold 83 is provided integrally with the movable-side mold 82, and the fixed-side integrated mold 86 is provided integrally with the fixed-side mold 81. Accordingly, the configuration of the mold 50 can be simplified, and the movable side integrated mold 83 can be interlocked with the movable side mold 82, so that the operation of the mold 50 can be simplified. In addition, since the third slide mold 56 is provided to be slidable with respect to the movable mold 82, the movable mold 82 can guide the slide of the third slide mold 56, and the third slide mold 56 The slide can be easily and stabilized.

It should be noted that the embodiment described above can be modified and embodied as follows.
-The pipe joint may be embodied as a cheese joint. For example, as shown in FIG. 16, the cheese joint 72 has the first connection portion 13 as the first connection portion 13 of the third header piece 10c, and the second connection portion 15 as the first header piece 10a. The second connecting portion 15 and the third connecting portion 17 are the third connecting portions 17 of the first header piece 10a.

  As shown in FIG. 17, the cheese joint 72 has the first connection portion 13 as the first connection portion 13 of the third header piece 10 c, and the second connection portion 15 and the third connection portion 17. Is the third connecting portion 17 of the first header piece 10a.

  The pipe joint may be embodied as a straight tubular joint member. For example, as shown in FIG. 18, the straight tubular joint member 73 has the first connection portion 13 as the first connection portion 13 of the third header piece 10 c and the second connection portion 15 as the first connection portion 13. The third connecting portion 17 of the header piece 10a is used.

  -In the 1st header piece 10a of the said embodiment, the external thread part 14 which comprises the 2nd connection part 15 is changed into the internal thread part 16, the union joint 29 is abbreviate | omitted, and main piping is connected to the said internal thread part 16. You may comprise so that 30 can be connected.

  In the first header piece 10a, the second connecting portion 15 is a connecting portion having the undercut portion 12, and the main pipe 30 is connected to the second connecting portion 15 via a joint. Also good.

  The pair of retaining portions 34 of the external screw insert member 28 may be configured by one retaining portion 34, or each retaining portion 34 may be configured by one or a plurality of protrusions. Further, the number of retaining portions 34 of the inner screw insert member 35 may be changed or the shape may be changed.

The header 10 may be configured by appropriately changing the number of header pieces 10a, 10b, and 10c constituting the header 10 and connecting a plurality of changed header pieces.
In the second embodiment, the ejector sleeve 85 may be omitted, and the movable-side integral mold 83 may be a separate slide core from the movable-side mold 82, and may be a movable mold that is slidable within the accommodation hole 84. . In this case, after the pipe joint body 11 is formed, the movable die 82 is separated from the fixed die 81, and the slide core is further retracted, thereby forcibly removing the undercut forming portion 60 and forming the undercut portion 12. can do.

  DESCRIPTION OF SYMBOLS 10 ... Header, 10a, 10b, 10c ... Header piece, 11 ... Pipe fitting main body, 12 ... Undercut part, 13 ... 1st connection part, 14 ... External thread part as a thread part, 15 ... 2nd connection part , 16 ... inner screw part as a thread part, 17 ... third connection part, 28 ... outer screw insert member, 34 ... retaining part, 35 ... inner screw insert member, 50 ... mold, 51 ... fixed mold 52 as a movable mold, 53 as a movable mold, 53 as a movable mold, 54 as a first slide mold as a movable mold, 55 as a second slide mold as a movable mold, and 56 as a movable mold. Third slide mold, 57... Gate, 58... External screw insert support, 64... Spiral groove, 66 ... Branch pipe, 81 ... Fixed side mold as a fixed mold, 82 ... Movable side mold as a movable mold Mold, 83 ... movable Movable integrated 83 as the mold.

Claims (8)

A method for manufacturing a pipe joint comprising at least a first connection part having an undercut part and a second connection part having a thread part,
The pipe joint main body constituting the pipe joint is formed of a resin containing a rubber-like elastic body, the thread portion is formed of an insert member different from the pipe joint main body, and a fixed mold and a movable mold are formed at the time of forming the pipe joint. An insert member is placed in a mold having a molding cavity between them, and a molten resin containing a rubber-like elastic body is injected from the gate of the mold into the cavity to mold a pipe joint body, and then the first A method of manufacturing a pipe joint, wherein a movable mold is forcibly extracted at the connecting portion and a movable mold is extracted at the second connection section to manufacture a pipe joint.   The pipe joint is a header piece constituting a header. The header piece is formed with a first connection portion and a second connection portion at both ends of a straight pipe, and a third pipe is connected to a branch pipe perpendicular to the straight pipe. The method for manufacturing a pipe joint according to claim 1, wherein a connection portion is formed.   The method for manufacturing a pipe joint according to claim 1 or 2, wherein the resin containing a rubber-like elastic body is an engineering plastic containing a thermoplastic elastomer.   The method for manufacturing a pipe joint according to claim 3, wherein the engineering plastic is polyphenylene sulfide (PPS) resin.   5. The pipe joint according to claim 1, wherein the resin forming the insert member is a glass fiber-containing polyphenylene sulfide (PPS) resin or a carbon fiber-containing polyphenylene sulfide (PPS) resin. Production method.   6. The insert member according to any one of claims 1 to 5, wherein the insert member is provided with a retaining portion that engages with a pipe joint main body to prevent the insert member from coming off and restricts rotation of the insert member in the circumferential direction. A manufacturing method of a pipe joint given in any 1 paragraph.   The method for manufacturing a pipe joint according to any one of claims 1 to 6, wherein a spiral groove is formed on an inner peripheral surface of an insert member in which the thread portion is an external thread portion.   The manufacturing method of the pipe joint according to any one of claims 2 to 7, wherein the insert member forming the third connection portion is disposed to face the gate of the mold.