JP6895091B2 - Manufacturing method of pipe fittings - Google Patents

Description

The present invention relates to, for example, a method for manufacturing a pipe joint for molding 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).

Patent Document 1 discloses a demolding device. That is, the cavity is formed by a fixed-side mold, a movable-side mold, and a rotating mold component (core mold), and a mold removing device is provided in the movable-side mold and is rotationally driven by a motor and the motor. It consists of a rotating body. Then, 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 is rotated, and the molded product is extracted from the core mold.

Japanese Unexamined Patent Publication No. 2012-35533

An object of the present invention is to provide a method for manufacturing a pipe joint capable of stably supporting an insert member in a mold.

In order to achieve the above object, the method for manufacturing a pipe joint of the present invention is a method for manufacturing a pipe joint having a connecting portion having a threaded portion, and is different from the pipe joint main body constituting the pipe joint. After forming the threaded portion with the insert member and arranging the insert member in the mold at the time of molding the pipe joint, the molten resin is injected from the gate of the mold into the cavity in the mold to form the pipe joint. The main body is molded, then the mold is opened, and then the pipe joint is manufactured by pulling out the mold at the connection portion, and the inner space of the insert member faces the gate of the mold. Are arranged.

Further, the method for manufacturing a pipe joint of the present invention is a method for manufacturing a pipe joint including at least a connection portion having an undercut portion and a connection portion having a threaded portion, and is a pipe joint main body constituting the pipe joint. Is formed of resin containing a rubber-like elastic body, the threaded part is formed of an insert member different from the pipe joint body, and a cavity for molding is formed between the fixed mold and the movable mold when molding the pipe joint. After arranging the insert member in the mold, the molten resin containing a rubber-like elastic body is injected into the cavity from the gate of the mold to form the pipe joint body, and then it is movable in the connection part having the undercut part. The mold is forcibly pulled out, and the movable mold is pulled out at the connecting portion having the threaded portion to manufacture a pipe joint, and the inner space of the insert member is arranged so as to face the gate of the mold.

According to the method for manufacturing a pipe joint of the present invention, there is an effect that the insert member can be stably supported in the mold.

(A) is a cross-sectional view showing the three header pieces constituting the header in the first embodiment in an exploded manner, and (b) is a cross-sectional view showing a header in which the header pieces are connected. An enlarged cross-sectional view showing the first header piece. An enlarged cross-sectional view showing a second header piece. (A) is an enlarged cross-sectional view showing a third header piece, and (b) is a partially enlarged cross-sectional view showing an undercut portion. The front view which shows the state which connected the main pipe and a branch pipe to a header. (A) is a cross-sectional view showing an external thread insert member, and (b) is a front view showing an external thread insert member. (A) is a cross-sectional view showing an internal thread insert member, (b) is a side view showing an internal thread insert member, and (c) is a front view showing an internal thread insert member. A cross-sectional view showing a mold for forming a pipe joint, and disassembling the first slide mold, the second slide mold, the third slide mold, and the external thread insert member and the internal thread insert member as a fixed mold and a movable mold. .. FIG. 8 is a cross-sectional view showing a state in which the external screw insert member is mounted on the second slide mold and the internal screw insert member is mounted on the third slide mold. A cross-sectional view showing a state in which a molten resin containing a rubber-like elastic body is injected from a gate into a cavity after molding a fixed mold and a movable mold to form a cavity. FIG. 10 is a cross-sectional view showing a state in which a movable mold is pulled out after the fixed mold is opened. The cross-sectional view which shows the mold for forming a pipe joint in 2nd Embodiment, and shows the state which the fixed side mold and the movable side mold are opened. FIG. 5 is a cross-sectional view showing a state in which a fixed-side mold and a movable-side mold are molded, and after the third slide mold is molded, molten resin is injected into the cavity. FIG. 13 is a cross-sectional view showing 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. FIG. 4 is a cross-sectional view showing a state in which the ejector sleeve is extruded from the state of FIG. 14 to forcibly pull out the undercut molded portion to form the undercut portion. An enlarged cross-sectional view showing another example of the present invention and showing a cheese joint. An enlarged cross-sectional view showing another example of the present invention and showing a cheese joint. An enlarged cross-sectional view showing another example of the present invention and showing a straight tubular joint.

(First Embodiment)
Hereinafter, the first embodiment embodying the present invention will be described in detail with reference to FIGS. 1 to 11.
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. 1A, a second header piece 10b [center portion of FIG. 1A] is connected to the first header piece 10a [right end portion of FIG. 1A], and the second header thereof is connected. A third header piece 10c [the 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 10a via the union joint 29, and the branch pipe 66 is connected to the first header piece 10a via the joint 65. The second header piece 10b is connected to the first header piece 10a and the third header piece 10c, and the branch pipe 66 is connected via the joint 65. The third header piece 10c is connected to the second header piece 10b, the main pipe 26 is connected, and the branch pipe 66 is connected via the 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, circulates to the main pipe 30 of the first header piece 10a, and branches to each branch pipe 66. It is supposed to be done.

As shown in FIG. 2, the pipe joint main body 11 constituting the first header piece 10a is formed in a substantially inverted T-shape in cross section, and has a first connecting portion 13 having an undercut portion 12 on the inner peripheral surface and an outer circumference. It has a second connecting portion 15 having an external threaded portion (male threaded portion) 14 on the surface and a third connecting portion 17 having an internal threaded portion (female threaded portion) 16 on the inner peripheral surface. The third connecting portion 17 is for connecting the branch pipe 66 that branches the fluid flowing between the first connecting portion 13 and the second connecting 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, and polyurethane-based thermoplastic elastomers. Examples of the rubber include ethylene-propylene-diene copolymer rubber (EPDM), ethylene-propylene copolymer rubber (EPM), butyl rubber (IIR), nitrile rubber (NR), styrene-butadiene copolymer rubber (SBR) and the like. .. One or two or more of these rubber-like elastic bodies are appropriately selected and used depending on the purpose of use and the like.

Further, as the resin (synthetic resin or natural resin), engineering plastic is preferable from the viewpoint of mechanical strength, heat resistance and the like. Examples of engineering plastics include polyphenylene sulfide (PPS) resin, polyamide (nylon) resin, polyacetal resin, polyester resin, polycarbonate resin, polysulfone resin, and polyimide resin. Among these engineering plastics, PPS resin is preferable because it has excellent physical properties such as heat-resistant water properties.

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 pipe joint body 11 to be molded is insufficient, and it is difficult for the first slide type 54, which will be described later, to be pulled out from the undercut portion 12, and the undercut portion. Molding of 12 becomes difficult, and as a result, the undercut portion 12 is damaged, which is not preferable. On the other hand, if it is more than 40% by mass, the undercut portion 12 can be easily formed, but it is not preferable because the mechanical properties of the obtained pipe joint main body 11 tend to deteriorate.

The first connecting portion 13 is formed in a cylindrical shape, and the undercut portion 12 is formed by an annular groove formed in an arc shape in cross section on the inner peripheral surface thereof. The undercut portion 12 is an obstacle when the first slide mold 54, which will be described later for molding the first connecting portion 13, is pulled out outward in the axial direction of the first connecting portion 13. Since the pipe joint body 11 is made of a resin containing a rubber-like elastic body, the first slide type 54 can be pulled out while suppressing damage to the undercut portion 12.

The second connecting portion 15 is configured by providing an external thread insert member 28, which is separate from the pipe joint main body 11, on the outer periphery of the pipe joint main body 11. The external thread insert member 28 uses a metal such as bronze or brass or a resin having a higher melting point (freezing point) than the resin containing the rubber-like elastic body, and is prevented from being deformed by heat of the molten resin 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 the glass fiber or carbon fiber is higher than the melting point of the PPS resin, the melting point of the PPS resin containing glass fiber or the PPS resin containing carbon fiber is higher than the melting point of the PPS resin. The content of glass fiber and 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 external thread insert member 28 over the entire inner peripheral surface. As shown in FIG. 2, the thin tubular portion 11a of the pipe joint body 11 formed on the inner peripheral portion of the external thread insert member 28 by the spiral groove 64 is pulled out of the second slide mold 55 described later after the insert molding. The risk of 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 on the inner end side of the external thread insert member 28, and the pipe joint main body. The external screw insert member 28 is prevented from coming off by engaging with the engaging recess 63 of 11. The outer peripheral surface of these retaining portions 34 is knurled to form uneven portions (not shown), and the rotation of the external screw insert member 28 in the circumferential direction is restricted. An external thread portion 14 is formed on the outer peripheral surface of the outer end portion of the external thread insert member 28, and the union joint 29 is screwed into the external thread portion 14.

Subsequently, the third connection portion 17 will be described. As shown in FIGS. 2 and 7 (a) to 7 (c), the third connecting portion 17 is provided with an internal thread insert member 35 that is separate from the pipe joint body 11 on the inner circumference of the pipe joint body 11. It is composed of. On the outer peripheral surface of the internal thread insert member 35, a retaining portion 34 formed by four protrusions formed in a columnar shape at intervals of 90 degrees in the circumferential direction is provided, and is engaged with the engaging recess 63 of the pipe joint body 11. In this way, the internal thread insert member 35 is prevented from coming off, and the rotation of the internal thread insert member 35 in the circumferential direction is restricted. The internal thread portion 16 is formed on the inner peripheral surface of the internal thread insert member 35, and the male thread 37 of the joint 65 is screwed.

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

Then, when the second header piece 10b is connected to the first header piece 10a, the locking ring 68 of the second connecting portion 15 of the second header piece 10b is attached to the first connecting portion 13 of the first header piece 10a. Engage 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 the second connection portion 15 and the second connection portion 15 of the second header piece 10b. It has the same configuration as the connection portion 17 of 3. The first connecting portion 13 is formed in a cylindrical shape, an undercut portion 12 is formed on the inner peripheral portion of the tip thereof, and a pair of locking convex portions 74 are formed on the outer peripheral surface. A cap 25 is fitted to the first connecting portion 13, and a retaining ring 27 for preventing the main pipe 26 from coming off is interposed between the inner peripheral portion of the cap 25 and the first connecting portion 13. There is. 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 convex portion 74 of the first connecting portion 13 is locked. A stainless steel cover body 44 is fitted on the outer periphery of the base end portion of the cap 25 to regulate the opening of the cap 25.

Then, when the third header piece 10c is connected to the second header piece 10b, the locking ring 68 of the second connecting portion 15 of the third header piece 10c is connected to the first connecting portion 13 of the second header piece 10b. Engage with the undercut portion 12. Further, the main pipe 26 is inserted into the first connecting portion 13 and is configured to be held so as not to come off.

A manufacturing apparatus for molding the header pieces 10a, 10b, and 10c configured as described above will be described. Since the manufacturing devices of the first header piece 10a, the second header piece 10b, and the third header piece 10c as the pipe joint are similar, the manufacturing device of the first header piece 10a will be described as a representative.

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

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

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 preformed separately from the pipe joint main body 11. The second slide type 55 and the third slide type 56 are 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 external thread insert support portion 58 is formed by an annular recess recessed in the tip surface of the second slide type 55, and the internal thread insert support portion 59 is formed by a stepped portion of the third slide type 56 having a columnar shape. ing.

The third slide type 56 and the internal thread insert member 35 are arranged so as to face the gate 57, and the internal thread insert member 35 is placed on the internal thread insert support portion 59 by the pressure of the molten resin injected from the gate 57. Be pressed. Regarding the arrangement of the internal screw insert member 35, the internal screw insert member 35 is inserted and inserted to the innermost part of the internal screw insert support portion 59 forming the stepped shape of the third slide type 56, and the internal screw is arranged by a simple procedure. The insert member 35 can be accurately arranged. The second slide type 55 is arranged below the fixed type 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, a method of manufacturing 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 10a, first, the external screw insert member 28 is arranged on the external screw insert support portion 58 of the second slide type 55, and then the external screw insert member 28 is arranged, and then the third slide type 56. The internal thread insert member 35 is arranged on the internal thread insert support portion 59 of the above. In this case, the external thread insert member 28 and the internal thread insert member 35 are preformed separately from the pipe joint body 11, and the melting point of the resin forming both the insert members 28 and 35 forms the pipe joint body 11. It is higher than the melting point of the resin. Therefore, 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 during molding of the pipe joint main body 11.

Subsequently, as shown in FIG. 10, the movable mold 52 is inserted into the fixed mold 51 and molded to form a cavity 53 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 from the gate 57 into the cavity 53 and performing insert molding according to a conventional method.

As shown in FIG. 11, after the insert molding, the fixed mold 51 divided into two is opened. After that, as shown by the alternate long and short dash line in FIG. 11, the first slide type 54 is pulled out from the first connecting portion 13 of the pipe joint main body 11. At this time, since the pipe joint body 11 is made of a resin containing a rubber-like elastic body, the first connecting portion 13 is elastically expanded by pulling the first slide mold 54 outward in the axial direction thereof. The first slide mold 54 can be forcibly pulled out without opening and expanding the diameter of the undercut portion 12 and damaging the undercut portion 12.

Similarly, as shown by the alternate long and short dash line in FIG. 11, the second slide type 55 and the third slide type 56 are not provided with the undercut portion 12 in the second connecting portion 15 and the third connecting portion 17. Therefore, by pulling the second slide type 55 and the third slide type 56 outward from each axis, the second slide type 55 and the third slide type 56 are quickly pulled out from the pipe joint body 11 without resistance and released. can do. In this way, the first header piece 10a having the first connecting portion 13, the second connecting portion 15, and the third connecting portion 17 can be manufactured by a simple operation.

The effects exhibited by the above first embodiment are summarized below.
(1) In the method for manufacturing the first header piece 10a in the first embodiment, the pipe joint body 11 is formed of a resin containing a rubber-like elastic body, and the threaded portions 14 and 16 are inserted separately from the pipe joint body 11. It is formed of members 28 and 35. Then, at the time of molding the first header piece 10a, after the insert members 28 and 35 are arranged in the mold 50, the molten resin containing the rubber-like elastic body is injected into the cavity 53 to mold the pipe joint main body 11. Next, the fixed mold 51 is opened, the first slide mold 54 is forcibly pulled out at the first connection portion 13, and the second slide mold 55 and the second slide mold 55 and the third connection portion 17 are formed at the second connection portion 15 and the third connection portion 17. The first header piece 10a is manufactured by pulling out the 3-slide mold 56.

Therefore, the pipe joint main body 11 can be quickly molded by the conventional method of the insert molding method, and the first connecting portion 13, the second connecting portion 15, and the third connecting portion 17 can be easily separated after the insert molding. It can be advanced by various operations.

Therefore, according to the method for manufacturing the first header piece 10a of the present embodiment, the first header piece 10a having the undercut portion 12 can be smoothly manufactured without causing a decrease in productivity.

(2) The resin containing the 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 a polyphenylene sulfide (PPS) resin. In this case, the first header piece 10a can exhibit particularly heat-resistant water characteristics.

(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 coming off. Therefore, the insert members 28 and 35 can be firmly fixed to the pipe joint main body 11 by restricting the rotation in the circumferential direction.

(5) A spiral groove 64 is formed on the inner peripheral surface of the external screw insert member 28. Therefore, when the second slide mold 55 is pulled out after the insert molding of the first header piece 10a, damage to the tubular portion 11a of the pipe joint main body 11 to be molded can be suppressed.

(6) The internal thread insert member 35 forming the third connection portion 17 is arranged so as to face the gate 57, and the external thread insert member 28 forming the second connection portion 15 is an external thread insert support portion. It is inserted and supported from above to below with respect to 58. Therefore, the internal thread insert member 35 can be supported on the internal thread insert support portion 59 in a stable state by the pressure of the molten resin injected from the gate 57, and the external thread insert member 28 can be supported on the external thread insert support portion 58 by its own weight. On the other hand, it can be easily supported.

(Second Embodiment)
Next, a second embodiment embodying the present invention will be described with reference to FIGS. 12 to 15. In this second embodiment, the parts different from the first embodiment will be mainly described.

As shown in FIG. 12, the mold 50 is composed of a fixed-side mold 81 as a fixed mold and a movable-side mold 82 as a movable mold. The first slide mold 54 forming the first connecting portion 13 having the undercut portion 12 and the third slide mold 56 forming the third connecting portion 17 in the first embodiment are provided on the movable side mold 82. The second slide mold 55 forming the second connecting portion 15 is provided on the fixed side mold 81. That is, the first slide mold 54 is integrally formed with the movable side mold 82 to become a movable side integrated mold 83 as a movable mold, and is formed so that the tip portion protrudes from the inside of the accommodating hole 84 of the movable side mold 82. ing. An ejector sleeve 85 is arranged on the outer periphery of the movable side integrated type 83, and is configured to pull out the molded pipe joint main body 11.

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

Subsequently, as shown in FIG. 13, the movable side mold 82 is molded into the fixed side mold 81, and in that state, the molten resin is injected into the cavity 53 to form the pipe joint main body 11.

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

After that, as shown in FIG. 15, the pipe joint main body 11 is pulled out from the movable side integrated mold 83 by pushing the ejector sleeve 85 toward the fixed side mold 81 (left direction in FIG. 15), and the undercut molding portion 60 Is forcibly removed, and the undercut portion 12 is formed.

As described above, in the second embodiment, the movable side integrated mold 83 is integrally provided with the movable side mold 82, and the fixed side integrated mold 86 is integrally provided with the fixed side mold 81. Therefore, 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, and the operation of the mold 50 can be simplified. In addition, since the third slide mold 56 is provided so as 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 can be guided. The slide can be easily and stabilized.

It is also possible to modify the embodiment as follows to embody it.
-The pipe joint may be embodied as a cheese joint. For example, as shown in FIG. 16, in the cheese joint 72, the first connecting portion 13 thereof is the first connecting portion 13 of the third header piece 10c, and the second connecting portion 15 is the first header piece 10a. The second connecting portion 15 is used, and the third connecting portion 17 is used as the third connecting portion 17 of the first header piece 10a.

Further, as shown in FIG. 17, in the cheese joint 72, the first connecting portion 13 thereof is used as the first connecting portion 13 of the third header piece 10c, and the second connecting portion 15 and the third connecting portion 17 are used. Is the third connecting portion 17 of the first header piece 10a.

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

In the first header piece 10a of the embodiment, the external threaded portion 14 constituting the second connecting portion 15 is changed to the internal threaded portion 16, the union joint 29 is omitted, and the main pipe is connected to the internal threaded portion 16. It may be configured so that 30 can be connected.

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

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

The number of header pieces 10a, 10b, and 10c constituting the header 10 may be appropriately changed, and the changed header pieces may be connected to form the header 10.
-In the second embodiment, the ejector sleeve 85 may be omitted, the movable side integrated mold 83 may be a slide core separate from the movable side mold 82, and the movable mold may be slidable in the accommodating hole 84. .. In this case, after molding the pipe joint body 11, the movable mold 82 is separated from the fixed mold 81, and the slide core is further retracted to forcibly pull out the undercut molding portion 60 to mold the undercut portion 12. can do.

The technical idea that can be grasped from the above embodiment will be described.
(1) A method for manufacturing a pipe joint having at least a connection part having an undercut part and a connection part having a threaded part, wherein the pipe joint body constituting the pipe joint is made of a resin containing a rubber-like elastic body. The threaded portion is formed by an insert member different from the pipe joint body, and the insert member is placed in a mold having a cavity for molding between the fixed mold and the movable mold when molding the pipe joint. After that, the molten resin containing a rubber-like elastic body is injected into the cavity from the gate of the mold to form the pipe joint body, and then the movable mold is forcibly removed at the connection part having the undercut part, and the threaded part is removed. A method for manufacturing a pipe joint in which a movable mold is extracted from the connecting portion to be provided to manufacture a pipe joint, and a spiral groove is formed on the inner peripheral surface of an insert member in which the threaded portion is an external threaded portion.

(2) A connecting portion formed at one end of a straight pipe and having an undercut portion, a connecting portion formed at the other end of the straight pipe, and a connecting portion formed in a branch pipe orthogonal to the straight pipe and having a threaded portion. It is a method of manufacturing a pipe joint having at least the above, in which the pipe joint body constituting the pipe joint is formed of a resin containing a rubber-like elastic body, and the threaded portion is formed of an insert member different from the pipe joint body. When molding a pipe joint, after arranging the insert member in a mold having a cavity for molding between the fixed mold and the movable mold, a molten resin containing a rubber-like elastic body is placed in the cavity from the gate of the mold. Is injected to form the main body of the pipe joint, then the movable mold is forcibly pulled out at the connection part having the undercut part, and the movable mold is pulled out at the connection part having the threaded part to manufacture the pipe joint and branch. A method for manufacturing a pipe joint in which an insert member forming a connecting portion having a threaded portion in a pipe is arranged so as to face the gate of a mold.

10 ... Header, 10a, 10b, 10c ... Header piece, 11 ... Pipe joint body, 12 ... Undercut part, 13 ... First connection part, 14 ... External threaded part as screw part, 15 ... Second connection part , 16 ... Internal threaded portion as a threaded portion, 17 ... Third connecting portion, 28 ... External threaded insert member, 34 ... Retaining part, 35 ... Internal threaded insert member, 50 ... Mold, 51 ... Fixed mold Fixed type as, 52 ... Movable type as movable type, 53 ... Cavity, 54 ... First slide type as movable type, 55 ... Second slide type as movable type, 56 ... As movable type 3rd slide mold, 57 ... gate, 58 ... external screw insert support, 64 ... spiral groove, 66 ... branch pipe, 81 ... fixed side mold as fixed mold, 82 ... movable side mold as movable mold Mold, 83 ... Movable side integrated type 83 as a movable mold.

Claims (2)

A method for manufacturing a pipe joint having a connection portion having a threaded portion, wherein the threaded portion is formed by an insert member different from the pipe joint main body constituting the pipe joint, and the pipe joint is the pipe joint main body. said that the insert member is fixed, Ri configuration der rotation is Ru is restricted of the insert member in the circumferential direction with respect to stop by and said pipe joint body exits from the pipe joint body, gold at the time of molding of the pipe joint to After arranging the insert member in the mold, molten resin is injected from the gate of the mold into the cavity in the mold to form the pipe joint body, then the mold is opened, and then the connection is made. In the part, the pipe joint is manufactured by pulling out the mold.
A method for manufacturing a pipe joint in which an inner space of the insert member is arranged so as to face the gate of the mold. A method for manufacturing a pipe joint including at least a connecting portion having an undercut portion and a connecting portion having a threaded portion.
The pipe joint 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 body, and the insert member is fixed to the pipe joint body. The insert member is prevented from coming off from the pipe joint body and its rotation in the circumferential direction with respect to the pipe joint body is restricted. After arranging the insert member in the mold having the cavity of, the molten resin containing the rubber-like elastic body is injected into the cavity from the gate of the mold to form the pipe joint body, and then in the connection part having the undercut part Forcibly pulls out the movable mold, and at the connection part with the threaded part, pulls out the movable mold to manufacture a pipe joint.
A method for manufacturing a pipe joint in which an inner space of the insert member is arranged so as to face the gate of the mold.

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