JP2019195960A - Pipe fitting manufacturing apparatus - Google Patents

Abstract

To manufacture an elbow type pipe fitting with smooth bends with no edges at the inner corners of channel holes.SOLUTION: A mold (1) for injection molding an elbow type pipe fitting has a curved cavity (3), and acts to insert and pull out an arc core pin (10) from an open end (3D) (3D) of the cavity (3) along an arc axis (L).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for an elbow-shaped pipe joint bent into a semicircular shape.

Conventionally, as shown in FIG. 13A, the resin elbow-type pipe joint 51 manufactured by injection molding is L-shaped as a whole, and the channel hole 52 has an outer corner portion 53 that is rounded. The inner corner portion 54 has a right-angled edge shape.
The reason is that, as shown in FIG. 13B, a conventional injection mold inserts a pair of core pins 55 and 56 into a cavity formed in the mold (nesting) from the orthogonal direction and melts the resin. This is because the core pins 55 and ₅₆ had to be pulled out in the directions of the arrows N ₅₅ and N ₅₆ after the resin was cooled and solidified.
If the inner corner portion 54 is formed in a round shape, the core pins 55 and 56 cannot be pulled out.
As described above, the inner corner 54 has to make the inner edge of the abutting portion 58 of the core pins 55 and 56 into a right-angled edge.

Therefore, conventionally, it has been proposed to use a placement core 60 as shown in FIG. 12 (see FIG. 8 of Patent Document 1).
That is, a manufacturing method (molding device) in which the placing core 60 and the core pins 55Z and 56Z in which the recessed portion into which the placing core 60 is fitted are notched are combined and placed in the cavity, and the resin is injection molded. It is.

However, At a 12, core pin 55Z as shown in from FIG. (A) (B), after pulled out as indicated by an arrow N _55, N ₅₆ and 56 z, shown in the placed core 60 FIG (C) It is necessary to decenter in the direction of arrow N ₆₀ and then pull out in the direction of arrow N ₆₁ in FIG.
The operation of the placing core 60 of FIGS. 12C, 12D and 12E is simple in the drawing of FIG. 12, but an actual injection molding apparatus (mold) requires a complicated mechanism. Also, failure rate is high and work efficiency is not good.

  Therefore, an inner cylinder made of silicon or the like is placed in the cavity, resin is injection-molded between the outer peripheral surface of the inner cylinder and the inner surface of the cavity, and then, after cooling, the inner cylinder made of silicon A manufacturing method has also been proposed in which the material is dragged out while utilizing its elastic deformation (see Patent Document 2).

JP 2009-184203 A JP 2011-47487 A

  However, the method for manufacturing a pipe joint described in Patent Document 2 has the following problems. (i) The radius of the inner corner portion 54 (see FIG. 13) of the elbow is only a very small value (but not a right angle). (ii) After injection molding, the inner cylindrical body such as silicon (installed in the cavity) has to be pulled out, and the drawing operation is extremely difficult. (iii) It takes time to manufacture, and it is difficult to repeatedly use the drawn inner cylinder, which may waste resources.

Accordingly, the present invention provides a method for manufacturing an elbow-type pipe joint by injection molding of a thermoplastic resin, with respect to the curved cavity formed in the mold, with the arc-shaped axis of the curved cavity. A circular arc core pin having a circular cross section is inserted, and then injection molding is performed, followed by cooling for a predetermined time and drawing along the arc-shaped axis.
Further, the present invention provides a method for producing an elbow-type pipe joint by injection molding of a thermoplastic resin, with respect to a mold having a curved cavity corresponding to the outer surface shape of the elbow-type pipe joint. From two open ends of the cavity, a pair of circular arc core pins having a circular cross section are inserted along the arcuate axis of the curved cavity, and the tip surfaces of the pair of core pins are held in pressure contact, After performing injection molding and cooling for a predetermined time, the pair of core pins are pulled out from the opening end while moving outward along the arcuate axis of the curved cavity, and the flow path hole of the elbow-type fitting The inner corner portion has a circular cross-sectional shape, and the cross-sectional shape perpendicular to the arc-shaped axis of the flow path hole is all circular.

The pipe joint manufacturing apparatus according to the present invention includes a mold for molding an elbow pipe joint by injection of a thermoplastic resin, along the arc-shaped axis of the curved cavity formed in the mold. An arcuate core pin is provided that performs an arcuate motion of insertion into the bent cavity and extraction outward while swinging.
In addition, a mold for molding an elbow-type pipe joint by injection of a thermoplastic resin, the mold has a curved cavity corresponding to the outer surface shape of the elbow-type pipe joint, and two places of the cavity are provided. Each open end is provided with an actuating pin that can reciprocate while reciprocating linearly, and an arc-shaped core pin having a circular cross section is attached to the tip of the actuating pin, and the tip of the actuating pin The arc-shaped core pin is inserted while oscillating along the arc-shaped axis of the curved cavity with the approaching or intrusion of the opening pin, and the tip of the working pin from the opening end is inserted. In accordance with separation or escape, the arc-shaped core pin is provided with arc-shaped motion forcing means that is pulled out outward from the curved cavity while swinging along the arc-shaped axis.

According to the method for manufacturing a pipe joint according to the present invention, the flow path of the obtained pipe joint can have an arcuate shape (from the conventional right-angled edge shape) in the longitudinal cross section thereof. In addition, the cross-sectional shape perpendicular to the arcuate axis can be circular regardless of the position in the axial direction. Accordingly, vortices (turbulent flow) are not generated in the fluid flowing through the flow path of the obtained pipe joint, the passage resistance is reduced, and the pressure loss can be remarkably reduced. That is, an elbow type pipe joint having a smooth flow path with a small pressure loss is obtained.
In addition, according to the pipe joint manufacturing apparatus according to the present invention, the configuration of the manufacturing apparatus can be simplified, the inner corner portion of the flow path has an arc shape (from a conventional right-angled edge shape), and has a cross-sectional shape. An elbow pipe joint having a circular 90 ° channel can be manufactured reliably and efficiently.

It is sectional drawing which shows one Embodiment of the manufacturing apparatus (and method) of the pipe joint which concerns on this invention, and shows the state before inserting an arc-shaped core pin with respect to the cavity of a metal mold | die. FIG. 3 is a cross-sectional view showing a state immediately before injection of a resin in a state where an arc-shaped core pin is inserted into a cavity of a mold. It is sectional drawing which shows the state in the middle of drawing | extracting which the resin shape | molded after the predetermined time passed from injection molding moved the core pin outward along the circular arc-shaped axis after cooling. It is sectional drawing explaining an example of the state which pulled the core pin from the metal mold | die, and the manufactured elbow type pipe fitting, Comprising: (A) is the drawing state of the core pin, and the elbow type pipe joint by which injection molding was carried out from a metal mold | die Sectional drawing which shows the state just before taking out, (B) is sectional drawing which showed an example of the elbow type pipe joint. It is a figure which shows the specific example of a core pin, Comprising: (A) is a perspective view from front-end | tip upper direction, (B) is a side view from front-end | tip direction, (C) is a perspective view from front-end | tip lower direction. It is a figure which shows the specific example of a core pin, Comprising: (A) is a top view, (B) is a front view, (C) is a bottom view. It is a figure which shows the specific example of a core pin, Comprising: (A) is a perspective view from base end upper direction, (B) is a side view seen from the base end direction, (C) is a perspective view from base end lower direction is there. It is a figure which shows an operation | movement block, Comprising: (A) is a front view, (B) is a side view. A guide cylinder is shown, (A) is a front view, (B) is a side view. The 2nd core pin which forms the large diameter end part of a pipe joint is shown, (A) is a front view, (B) is a half-rod cross-sectional side view. The operation | movement pin is shown, (A) is a side view, (B) is a front view, (C) is CC sectional expanded view of (A). It is sectional explanatory drawing which showed the manufacturing method of the prior art example one by one. It is a figure which shows another prior art example, Comprising: (A) is a longitudinal cross-sectional view of the conventional elbow type pipe joint, (B) is a partial cross section side view for demonstrating the conventional manufacturing apparatus and manufacturing method.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
1 to 4 show an embodiment of a method for manufacturing an elbow type pipe joint according to the present invention (hereinafter sometimes simply referred to as “elbow joint”) by injection molding of a thermoplastic resin, and a manufacturing apparatus. The form is shown.

First, a description will be given of (mainly) an elbow joint manufacturing apparatus. Reference numeral 1 denotes a mold for molding the elbow joint E, which includes a pair of inserts 2 and 2 that can be separated and combined in a plane parallel to the paper surface of the drawing.
The mold 1 has a curved cavity 3 corresponding to the outer surface shape of the elbow joint E to be injection-molded by combining the pair of inserts 2 and 2.
The cavity 3 is composed of a bent main body forming portion 3A of about 90 °, and a medium diameter portion 3B and a large diameter portion 3C that are successively formed from both ends of the bent main body forming portion 3A. Are open ends 3D and 3D that open from the mold 1.

Reference numeral 5 denotes an actuating pin that can freely approach and separate while reciprocating linearly with respect to the opening end 3 </ b> D of the cavity 3. That is, the pair of actuating pins 5 and 5 whose axes are arranged orthogonally operate linearly with respect to the open ends 3D and 3D of the cavity 3 of the mold 1 as shown in FIGS. While approaching, the tip 5A enters, and from FIG. 2 to FIG. 4 to FIG. 4, it is separated from the opening end 3D by the drawing (retracting) operation.
As shown in FIG. 11, the actuating pin 5 has a pair of cross sections formed by a basic cylindrical portion 5B, a square plate-like base portion 5C, and a groove 5E formed in a cutout shape from the tip surface 5D. It has three-month-shaped protrusions 5F, 5F. Moreover, as shown in the side view of FIG. 11A, the protrusions 5F and 5F of the tip 5A have cam holes (cam grooves) that form a predetermined inclination angle θ ₅ with respect to the pin shaft center 5G. 5H is provided (see FIG. 11C).

An arcuate core pin 10 having a circular cross section is attached to the distal end portion 5A of such an operating pin 5.
Specifically, as shown in FIGS. 5, 6, and 7, the core pin 10 has a small chamfered portion 11 and a protruding piece portion 12 that are continuously provided at the base end. The projecting piece 12 is provided with a through hole 13.

As shown in FIGS. 1 to 4, a projecting piece in which a movable cam shaft 14 is connected to the arc-shaped core pin 10 by being fitted in the cam hole 5 </ b> H formed in the tip portion 5 </ b> A of the operating pin 5. It is inserted (press-fit) and fixed in the through-hole 13 of the portion 12.
That is, the movement of the base end side of the arc-shaped core pin 10 is restricted by the cam hole 5H and the cam shaft 14.

1 to 4 and 8, reference numeral 6 denotes an operation block that linearly reciprocates as indicated by arrows N ₆ and N ₇ by an actuator such as a cylinder (not shown), and the operation pin 5 is inserted and fixed. 6A. The operating block 6 is concentric with the hole 6A for the operating pin 5 and has a recess 6B formed on one surface thereof that contacts the mold 1. The guide cap 7 (FIG. 9) is formed in the recess 6B. Is inserted and fixed. The guide cap 7 has an inner flange portion 7B having a hole portion 7A at the tip. The guide cap 7 can linearly reciprocate (in the axial direction) in the guide cap 7, and the second core pin 8 has an inner fitting shape. It is assembled.
In other words, the arc-shaped core pin 10 described above is referred to as a first core pin, and the core pin 8 that reciprocates linearly is referred to as a second core pin.

The second core pin 8 has a shape as shown in FIG. 10, has a square plate piece 8A for non-rotating at the base end in the shape of an outer casing, and a hole portion into which the operating pin 5 can be inserted. 8B over substantially the entire length. Moreover, it is a cylinder part shape which has a multi-step outer peripheral surface, and as shown in FIGS. 2 and 3, the elbow joint E as shown in FIG. 4 corresponds to the medium diameter part 3B and the large diameter part 3C. A cylindrical portion with a medium diameter and a large diameter near the opening end is formed.
A guide plate 8D having a guide circular hole 8C is fixed to the tip of the second core pin 8.

The movement of the core pin 10 on the tip side is restricted by a guide circular hole 8C penetrating the guide plate 8D.
That is, in the embodiment shown in FIGS. 1 to 11, the arcuate core pin 10 swings along the arcuate axis L ₃ of the curved cavity 3, and the mold 1 is moved from the curved cavity 3. The arc-shaped motion forcing means Z is pulled out outward from the guide hole 8C of the guide plate 8D, the cam hole 5H and the cam mechanism K of the cam shaft 14. Configured.

Thus, as shown in FIG. 1, according to the present invention, the operation block 6 is linearly moved in the direction of the arrow N ₆ by an actuator not shown, and the tip of the operation pin 5 held by the block 6 is made of gold. access to the open end 3D of type 1 of the cavity 3, and, with the penetration shown in Figure 2 of subsequently, arcuate core pin 10 is swung along an arcuate axis L ₃ of curved shape cavity 3 The circular distal end surfaces 10A and 10A of the arc-shaped core pin 10 are brought into contact with each other (pressure contact), and then resin injection molding (as shown in FIG. 3) is performed, and after cooling for a predetermined time, the operation pin 5 is moved in the arrow N ₇ direction, the leading end of the operating pin 5, to separate or escape from the open end 3D of the cavity 3, arcuate core pin 10, along an arcuate axis L ₃ swings Arc forcing means Z pulled out from cavity 3 while doing so , It has been provided.
As shown in FIG. 10 and FIGS. 1 to 4, the guide circular hole 8 </ b> C has a portion in sliding contact with the inner peripheral surface (having a small radius of curvature) of the arc-shaped core pin 10 (the wall of the guide plate 8 </ b> D). In the range of thickness, it is formed on the rounded surface or the inclined surface 16.

In FIG. 4B, the 90 ° arcuate channel hole range 20 with dots is a range in which the inner surface shape is determined by the pair of approximately 45 ° arcuate core pins 10 and 10 described above. I can say that. It is also preferable to provide a small convex portion on one of the tip surfaces 10A and 10A that are in contact with each other and a small concave portion on the other to prevent misalignment (not shown).
In the above-described embodiment, the manufacturing apparatus is provided with a pair of arcuate core pins 10 and 10 of about 45 °. However, this is provided with a single arcuate core pin 10 of about 90 ° and a cam mechanism K is provided. The same flow path hole 20 may be formed by a single arcuate core pin 10 of about 90 ° by changing to one that generates a large swing angle, or by adding or replacing a link mechanism.

Next, a method for manufacturing the elbow joint E will be described below.
The present invention is a method of manufacturing by injection molding of a thermoplastic resin, and two locations of the cavity 3 with respect to a mold 1 (see FIG. 1) having a curved cavity 3 corresponding to the outer surface shape of the elbow joint E. from the open end 3D, 3D, a circular cross section of the pair of arc-shaped core pin 10, 10 inserted along an arcuate axis L ₃ of curved shape cavity 3, as shown in FIG. 2, a pair of the core pin 10 , 10 while holding the tip face 10A in pressure contact, a thermoplastic resin is injected into the cavity 3 (injection molding is performed), and after cooling for a predetermined time, the pair of core pins 10, 10 are bent into the curved cavity 3 pulled open end 3D, the 3D while moving outwardly along an arcuate axis L ₃ of. Then, the mold 1 is separated from the mating surface, and the molded elbow joint E is taken out as shown in FIGS.

As shown in FIG. 4B, the longitudinal cross-sectional shape of the inner corner portion 21 of the flow path hole 20 of the elbow joint E is an arc, and the cross section is perpendicular to the arc-shaped axis L ₃ of the flow path hole 20. It is a method of making the shape all circular (wherever it crosses).
That is, a right-angled edge is not formed in the inner corner portion 54 as shown in FIG. 13A of the conventional example, and a beautiful arc shape is obtained as shown in FIG. 4B. Moreover, as shown in FIG. 4 (B), in an arc shape with the center point O ₂₀ of the arcuate axis L ₃ and the common, the inner corner portion 21 and the outer corner portion 22, is formed. In other words, the channel hole 20 is formed in a shape obtained by dividing a (confectionery) donut into four parts.

As described in detail above, the present invention relates to the curved cavity 3 formed in the mold 1 in the manufacturing method of manufacturing an elbow pipe joint by injection molding of a thermoplastic resin. An arc-shaped core pin 10 having a circular cross section is inserted along the arc-shaped axis L ₃ of the cavity 3, and then injection molding is performed. After cooling for a predetermined time, the core pin 10 is drawn along the arc-shaped axis L _3. Because of this method, a right-angled edge like the conventional elbow type pipe joint 51 (shown in FIG. 13) does not occur in the inner corner portion 54, and it can be formed into an arc shape having a sufficiently large radius of curvature. Therefore, the inner surface of the channel hole 20 of the manufactured elbow type pipe joint has a circular cross-sectional shape that is constant, the fluid flows smoothly without generating vortices (turbulent flow), the passage resistance is reduced, and the pressure loss is also reduced. It can be significantly reduced. Since many elbow joints are used for one piping pipe in an actual piping site, the effect of reducing the overall pressure loss is remarkable.
Also, along an arcuate axis L _3, by pulling out without deflection core to core pin 10, the inner surface of the flow path hole 20 of the molded article (elbow fitting E) is, at the time of withdrawal, not adhere scratches It becomes a high-quality molded product with a smooth inner surface.

Further, in the manufacturing method of manufacturing the elbow pipe joint by injection molding of a thermoplastic resin, the cavity 3 is compared with the mold 1 having the curved cavity 3 corresponding to the outer surface shape of the elbow pipe joint. two places open end 3D of the 3D, a circular cross section of the pair of arcuate core pin 10, 10 is inserted along an arcuate axis L ₃ of the curved shape cavity 3, the pair of core pin 10, 10 outside of the distal end surface 10A, the 10A while maintaining the pressure contact shape by performing injection molding, after a predetermined time cooling, the pair of core pins 10 and 10, along an arcuate axis L ₃ of the curved shape cavity 3 The inner corner portion 21 of the elbow-type pipe joint E is drawn out from the open ends 3D and 3D while moving in the direction of the arc, and the inner corner portion 21 of the elbow-type pipe joint E has an arcuate cross-sectional shape. By making all the cross-sectional shapes orthogonal to the arcuate axis L ₃ circular Therefore, it is easy to manufacture and suitable for mass production. In particular, since the operation stroke for inserting and extracting the arc-shaped core pin 10 is short, the manufacturing apparatus can be made compact, and the implementation is inexpensive and reliable. The manufactured elbow-type pipe joint does not have the right-angled edge of the conventional elbow-type pipe joint 51 (see FIG. 13) in the inner corner portion 54, and can have a round shape with a sufficiently large radius of curvature. . Moreover, the inner surface of the channel hole 20 has a circular cross-sectional shape and is constant, and the fluid flows smoothly without generating vortices (turbulent flow), pressure loss is significantly reduced, and energy can be reduced. .

Further, the manufacturing apparatus of the present invention includes a mold 1 for molding an elbow pipe joint E by injection of a thermoplastic resin, and the arcuate axis L ₃ of a curved cavity 3 formed in the mold 1. Since it has an arc-shaped core pin 10 that swings along the arc-shaped motion of insertion into the curved cavity 3 and withdrawing outward, it is placed as shown in FIG. Efficient mass production can be realized without using the child 60. In the manufactured elbow type pipe joint E, the fluid flows smoothly and the pressure loss can be remarkably reduced.

The mold 1 includes a mold 1 for molding the elbow pipe joint E by injection of a thermoplastic resin, and the mold 1 has a curved cavity 3 corresponding to the outer surface shape of the elbow pipe joint E, An operating pin 5 that is linearly reciprocated and freely separable is provided for each of the two open ends 3D and 3D of the cavity 3, and the distal end portion 5A of the operating pin 5 has a circular cross section. An arc-shaped core pin 10 is attached, and the arc-shaped core pin 10 swings along the arc-shaped axis L ₃ of the curved cavity 3 as the tip of the operating pin 5 approaches or enters the opening end 3D. while being inserted while moving, with the separation or escape from the open end 3D of the tip of the operating pin 5, the said arcuate core pin 10 while swinging along the arcuate axis L ₃ curve Forcing an arc-shaped motion to be pulled out from the cylindrical cavity 3 Since Z is configured to drive the operating pin 5 that reciprocates linearly, it can be easily driven by an actuator that is easily available at a low cost. With such an operating pin 5, pressure loss is caused in the elbow type pipe joint E. Thus, it is possible to reliably form the flow path holes 20 with extremely few.

1 Mold 3 Curved Cavity 3D Open End 5 Actuation Pin 5A Tip
10 Arc core pin
10A Tip surface
20 Channel hole
21 Inner corner E Elbow fitting (Elbow fitting)
L ₃ Arc-shaped shaft center Z Arc-shaped motion forcing means

The present invention relates to a manufacturing apparatus of curvature the elbow fitting to 4 semicircular.

Conventionally, as shown in FIG. 13A, the resin elbow-type pipe joint 51 manufactured by injection molding is L-shaped as a whole, and the channel hole 52 has an outer corner portion 53 that is rounded. The inner corner portion 54 has a right-angled edge shape.
The reason is that, as shown in FIG. 13B, a conventional injection mold inserts a pair of core pins 55 and 56 into a cavity formed in the mold (nesting) from the orthogonal direction and melts the resin. This is because the core pins 55 and ₅₆ had to be pulled out in the directions of the arrows N ₅₅ and N ₅₆ after the resin was cooled and solidified.
If the inner corner portion 54 is formed in a round shape, the core pins 55 and 56 cannot be pulled out.
As described above, the inner corner 54 has to make the inner edge of the abutting portion 58 of the core pins 55 and 56 into a right-angled edge.

Therefore, conventionally, it has been proposed to use a placement core 60 as shown in FIG. 12 (see FIG. 8 of Patent Document 1).
That is, a manufacturing method (molding device) in which the placing core 60 and the core pins 55Z and 56Z in which the recessed portion into which the placing core 60 is fitted are notched are combined and placed in the cavity, and the resin is injection molded. It is.

However, At a 12, core pin 55Z as shown in from FIG. (A) (B), after pulled out as indicated by an arrow N _55, N ₅₆ and 56 z, shown in the placed core 60 FIG (C) It is necessary to decenter in the direction of arrow N ₆₀ and then pull out in the direction of arrow N ₆₁ in FIG.
The operation of the placing core 60 of FIGS. 12C, 12D and 12E is simple in the drawing of FIG. 12, but an actual injection molding apparatus (mold) requires a complicated mechanism. Also, failure rate is high and work efficiency is not good.

  Therefore, an inner cylinder made of silicon or the like is placed in the cavity, resin is injection-molded between the outer peripheral surface of the inner cylinder and the inner surface of the cavity, and then, after cooling, the inner cylinder made of silicon A manufacturing method has also been proposed in which the material is dragged out while utilizing its elastic deformation (see Patent Document 2).

JP 2009-184203 A JP 2011-47487 A

  However, the method for manufacturing a pipe joint described in Patent Document 2 has the following problems. (i) The radius of the inner corner portion 54 (see FIG. 13) of the elbow is only a very small value (but not a right angle). (ii) After injection molding, the inner cylindrical body such as silicon (installed in the cavity) has to be pulled out, and the drawing operation is extremely difficult. (iii) It takes time to manufacture, and it is difficult to repeatedly use the drawn inner cylinder, which may waste resources.

Therefore, the pipe joint manufacturing apparatus according to the present invention includes a mold for molding the elbow pipe joint (E) by injection of a thermoplastic resin, and the mold corresponds to the outer surface shape of the elbow pipe joint. The curved cavity, and the curved cavity has a curved main body forming portion, and a medium diameter portion and a large diameter portion for pipe joining sequentially connected to both ends of the curved main body forming portion, respectively. Each of the two open ends of the cavity is provided with an actuating pin that can be reciprocated while reciprocating linearly, and an arc-shaped core pin having a circular cross section is attached to the tip of the actuating pin. A second core pin surrounding the base end side of the arc-shaped core pin as the first core pin is disposed so as to be able to enter and retract with respect to the large diameter portion and the medium diameter portion of the cavity; The core pin is straight along the same axis with respect to the operating pin. It is externally fitted to be slidable and inserted while the arcuate core pin swings along the arcuate axis of the curved cavity as the tip of the actuating pin approaches or enters the open end. In addition, the arc-shaped core pin swings along the arc-shaped axis and is pulled out outward from the curved cavity as the tip of the operating pin is separated from or escaped from the open end. An arcuate motion forcing means, wherein the arcuate motion forcing means comprises an arcuate core pin guiding circular hole penetrating through a guide plate at the tip of the second core pin, a base end of the arcuate core pin, and the operation And a cam mechanism that interlocks and connects the tip of the pin.

According to the pipe joint manufacturing apparatus according to the present invention, the configuration of the manufacturing apparatus can be simplified, the flow path inner corner portion is arc-shaped (from the conventional right-angled edge shape), and the cross-sectional shape is circular. An elbow type pipe joint having a certain 90 ° channel can be manufactured reliably and efficiently.

Shows an embodiment of the manufacturing equipment of the pipe joint according to the present invention, relative to the mold cavity, is a cross-sectional view showing a state before inserting the arc-shaped core pin. FIG. 3 is a cross-sectional view showing a state immediately before injection of a resin in a state where an arc-shaped core pin is inserted into a cavity of a mold. It is sectional drawing which shows the state in the middle of drawing | extracting which the resin shape | molded after the predetermined time passed from injection molding moved the core pin outward along the circular arc-shaped axis after cooling. It is sectional drawing explaining an example of the state which pulled the core pin from the metal mold | die, and the manufactured elbow type pipe fitting, Comprising: (A) is the drawing state of the core pin, and the elbow type pipe joint by which injection molding was carried out from a metal mold | die Sectional drawing which shows the state just before taking out, (B) is sectional drawing which showed an example of the elbow type pipe joint. It is a figure which shows the specific example of a core pin, Comprising: (A) is a perspective view from front-end | tip upper direction, (B) is a side view from front-end | tip direction, (C) is a perspective view from front-end | tip lower direction. It is a figure which shows the specific example of a core pin, Comprising: (A) is a top view, (B) is a front view, (C) is a bottom view. It is a figure which shows the specific example of a core pin, Comprising: (A) is a perspective view from base end upper direction, (B) is a side view seen from the base end direction, (C) is a perspective view from base end lower direction is there. It is a figure which shows an operation | movement block, Comprising: (A) is a front view, (B) is a side view. A guide cylinder is shown, (A) is a front view, (B) is a side view. The 2nd core pin which forms the large diameter end part of a pipe joint is shown, (A) is a front view, (B) is a half-rod cross-sectional side view. The operation | movement pin is shown, (A) is a side view, (B) is a front view, (C) is CC sectional expanded view of (A). It is sectional explanatory drawing which showed the manufacturing method of the prior art example one by one. It is a figure which shows another prior art example, Comprising: (A) is a longitudinal cross-sectional view of the conventional elbow type pipe joint, (B) is a partial cross section side view for demonstrating the conventional manufacturing apparatus and manufacturing method.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
1 to 4, elbow pipe joint according to the present invention (hereinafter, simply referred to as "elbow fitting"), and an embodiment of to that production equipment manufactured by injection molding of a thermoplastic resin Show.

First, a description will be given of (mainly) an elbow joint manufacturing apparatus. Reference numeral 1 denotes a mold for molding the elbow joint E, which includes a pair of inserts 2 and 2 that can be separated and combined in a plane parallel to the paper surface of the drawing.
The mold 1 has a curved cavity 3 corresponding to the outer surface shape of the elbow joint E to be injection-molded by combining the pair of inserts 2 and 2.
The cavity 3 is composed of a bent main body forming portion 3A of about 90 °, and a medium diameter portion 3B and a large diameter portion 3C that are successively formed from both ends of the bent main body forming portion 3A. Are open ends 3D and 3D that open from the mold 1.

Reference numeral 5 denotes an actuating pin that can freely approach and separate while reciprocating linearly with respect to the opening end 3 </ b> D of the cavity 3. That is, the pair of actuating pins 5 and 5 whose axes are arranged orthogonally operate linearly with respect to the open ends 3D and 3D of the cavity 3 of the mold 1 as shown in FIGS. While approaching, the tip 5A enters, and from FIG. 2 to FIG. 4 to FIG. 4, it is separated from the opening end 3D by the drawing (retracting) operation.
As shown in FIG. 11, the actuating pin 5 has a pair of cross sections formed by a basic cylindrical portion 5B, a square plate-like base portion 5C, and a groove 5E formed in a cutout shape from the tip surface 5D. It has three-month-shaped protrusions 5F, 5F. Moreover, as shown in the side view of FIG. 11A, the protrusions 5F and 5F of the tip 5A have cam holes (cam grooves) that form a predetermined inclination angle θ ₅ with respect to the pin shaft center 5G. 5H is provided (see FIG. 11C).

An arcuate core pin 10 having a circular cross section is attached to the distal end portion 5A of such an operating pin 5.
Specifically, as shown in FIGS. 5, 6, and 7, the core pin 10 has a small chamfered portion 11 and a protruding piece portion 12 that are continuously provided at the base end. The projecting piece 12 is provided with a through hole 13.

As shown in FIGS. 1 to 4, a projecting piece in which a movable cam shaft 14 is connected to the arc-shaped core pin 10 by being fitted in the cam hole 5 </ b> H formed in the tip portion 5 </ b> A of the operating pin 5. It is inserted (press-fit) and fixed in the through-hole 13 of the portion 12.
That is, the movement of the base end side of the arc-shaped core pin 10 is restricted by the cam hole 5H and the cam shaft 14.

1 to 4 and 8, reference numeral 6 denotes an operation block that linearly reciprocates as indicated by arrows N ₆ and N ₇ by an actuator such as a cylinder (not shown), and the operation pin 5 is inserted and fixed. 6A. The operating block 6 is concentric with the hole 6A for the operating pin 5 and has a recess 6B formed on one surface thereof that contacts the mold 1. The guide cap 7 (FIG. 9) is formed in the recess 6B. Is inserted and fixed. The guide cap 7 has an inner flange portion 7B having a hole portion 7A at the tip. The guide cap 7 can linearly reciprocate (in the axial direction) in the guide cap 7, and the second core pin 8 has an inner fitting shape. It is assembled.
In other words, the arc-shaped core pin 10 described above is referred to as a first core pin, and the core pin 8 that reciprocates linearly is referred to as a second core pin.

The second core pin 8 has a shape as shown in FIG. 10, has a square plate piece 8A for non-rotating at the base end in the shape of an outer casing, and a hole portion into which the operating pin 5 can be inserted. 8B over substantially the entire length. Moreover, it is a cylinder part shape which has a multi-step outer peripheral surface, and as shown in FIGS. 2 and 3, the elbow joint E as shown in FIG. 4 corresponds to the medium diameter part 3B and the large diameter part 3C. A cylindrical portion with a medium diameter and a large diameter near the opening end is formed.
A guide plate 8D having a guide circular hole 8C is fixed to the tip of the second core pin 8.

The movement of the core pin 10 on the tip side is restricted by a guide circular hole 8C penetrating the guide plate 8D.
That is, in the embodiment shown in FIGS. 1 to 11, the arcuate core pin 10 swings along the arcuate axis L ₃ of the curved cavity 3, and the mold 1 is moved from the curved cavity 3. The arc-shaped motion forcing means Z is pulled out outward from the guide hole 8C of the guide plate 8D, the cam hole 5H and the cam mechanism K of the cam shaft 14. Configured.

Thus, as shown in FIG. 1, according to the present invention, the operation block 6 is linearly moved in the direction of the arrow N ₆ by an actuator not shown, and the tip of the operation pin 5 held by the block 6 is made of gold. access to the open end 3D of type 1 of the cavity 3, and, with the penetration shown in Figure 2 of subsequently, arcuate core pin 10 is swung along an arcuate axis L ₃ of curved shape cavity 3 The circular distal end surfaces 10A and 10A of the arc-shaped core pin 10 are brought into contact with each other (pressure contact), and then resin injection molding (as shown in FIG. 3) is performed, and after cooling for a predetermined time, the operation pin 5 is moved in the arrow N ₇ direction, the leading end of the operating pin 5, to separate or escape from the open end 3D of the cavity 3, arcuate core pin 10, along an arcuate axis L ₃ swings Arc forcing means Z pulled out from cavity 3 while doing so , It has been provided.
As shown in FIG. 10 and FIGS. 1 to 4, the guide circular hole 8 </ b> C has a portion in sliding contact with the inner peripheral surface (having a small radius of curvature) of the arc-shaped core pin 10 (the wall of the guide plate 8 </ b> D). In the range of thickness, it is formed on the rounded surface or the inclined surface 16.

In FIG. 4B, the 90 ° arcuate channel hole range 20 with dots is a range in which the inner surface shape is determined by the pair of approximately 45 ° arcuate core pins 10 and 10 described above. I can say that. It is also preferable to provide a small convex portion on one of the tip surfaces 10A and 10A that contact each other and a small concave recess on the other to prevent misalignment (not shown) .

Next, a method for manufacturing the elbow joint E will be described below.
The present invention is a method of manufacturing by injection molding of a thermoplastic resin, and two locations of the cavity 3 with respect to a mold 1 (see FIG. 1) having a curved cavity 3 corresponding to the outer surface shape of the elbow joint E. from the open end 3D, 3D, a circular cross section of the pair of arc-shaped core pin 10, 10 inserted along an arcuate axis L ₃ of curved shape cavity 3, as shown in FIG. 2, a pair of the core pin 10 , 10 while holding the tip face 10A in pressure contact, a thermoplastic resin is injected into the cavity 3 (injection molding is performed), and after cooling for a predetermined time, the pair of core pins 10, 10 are bent into the curved cavity 3 pulled open end 3D, the 3D while moving outwardly along an arcuate axis L ₃ of. Then, the mold 1 is separated from the mating surface, and the molded elbow joint E is taken out as shown in FIGS.

As shown in FIG. 4B, the longitudinal cross-sectional shape of the inner corner portion 21 of the flow path hole 20 of the elbow joint E is an arc, and the cross section is perpendicular to the arc-shaped axis L ₃ of the flow path hole 20. It is a method of making the shape all circular (wherever it crosses).
That is, a right-angled edge is not formed in the inner corner portion 54 as shown in FIG. 13A of the conventional example, and a beautiful arc shape is obtained as shown in FIG. 4B. Moreover, as shown in FIG. 4 (B), in an arc shape with the center point O ₂₀ of the arcuate axis L ₃ and the common, the inner corner portion 21 and the outer corner portion 22, is formed. In other words, the channel hole 20 is formed in a shape obtained by dividing a (confectionery) donut into four parts.

As described above, in the manufacturing method for manufacturing the elbow pipe joint by injection molding of thermoplastic resin, the arcuate shape of the curved cavity 3 is compared with the curved cavity 3 formed in the mold 1. Since the arc-shaped core pin 10 having a circular cross section is inserted along the axis L ₃ , then injection molding is performed, and after cooling for a predetermined time, it is drawn along the arc-shaped axis L ₃ . A right-angled edge like the conventional elbow type pipe joint 51 (shown in FIG. 13) does not occur in the inner corner portion 54, and can be formed into an arc shape having a sufficiently large radius of curvature. Therefore, the inner surface of the channel hole 20 of the manufactured elbow type pipe joint has a circular cross-sectional shape that is constant, the fluid flows smoothly without generating vortices (turbulent flow), the passage resistance is reduced, and the pressure loss is also reduced. It can be significantly reduced. Since many elbow joints are used for one piping pipe in an actual piping site, the effect of reducing the overall pressure loss is remarkable.
Also, along an arcuate axis L _3, by pulling out without deflection core to core pin 10, the inner surface of the flow path hole 20 of the molded article (elbow fitting E) is, at the time of withdrawal, not adhere scratches It becomes a high-quality molded product with a smooth inner surface.

Further, with respect to the mold 1 having a curved shape cavity 3 corresponding to the outer contour of the upper Symbol elbow fitting open end 3D of two positions of the cavity 3, from 3D, a pair of arcuate core pin of circular cross 10, 10 and inserted along an arcuate axis L ₃ of the curved shape cavity 3, while maintaining the distal end surface 10A of the pair of core pin 10, 10, the 10A to the pressure contact shape by performing injection molding, after a predetermined time cooling, the pair of core pins 10 and 10, the curved shape cavity while being moved above the open end 3D 3 along the arcuate axis L ₃ outward, withdrawal from 3D, the elbow fitting E a longitudinal section shaped arcuate inner corner 21 of the flow path hole 20, moreover, since all the cross-sectional shape orthogonal to the arc-shaped axis L ₃ of the flow path hole 20 is in a way that a circular This method is easy to manufacture and suitable for mass production. In particular, since the operation stroke for inserting and extracting the arc-shaped core pin 10 is short, the manufacturing apparatus can be made compact, and the implementation is inexpensive and reliable. The manufactured elbow-type pipe joint does not have the right-angled edge of the conventional elbow-type pipe joint 51 (see FIG. 13) in the inner corner portion 54, and can have a round shape with a sufficiently large radius of curvature. . Moreover, the inner surface of the channel hole 20 has a circular cross-sectional shape and is constant, and the fluid flows smoothly without generating vortices (turbulent flow), pressure loss is significantly reduced, and energy can be reduced. .

As detailed above, the mold 1 for molding the elbow pipe joint E by injection of thermoplastic resin is provided, and along the arcuate axis L ₃ of the curved cavity 3 formed in the mold 1. Since the arcuate core pin 10 that performs the arcuate motion of the insertion into the curved cavity 3 and the outward drawing while swinging is provided, the placement core 60 as shown in FIG. Efficient mass production can be realized without using In the manufactured elbow type pipe joint E, the fluid flows smoothly and the pressure loss can be remarkably reduced.

The mold 1 includes a mold 1 for molding the elbow pipe joint E by injection of a thermoplastic resin, and the mold 1 has a curved cavity 3 corresponding to the outer surface shape of the elbow pipe joint E, An operating pin 5 that is linearly reciprocated and freely separable is provided for each of the two open ends 3D and 3D of the cavity 3, and the distal end portion 5A of the operating pin 5 has a circular cross section. An arc-shaped core pin 10 is attached, and the arc-shaped core pin 10 swings along the arc-shaped axis L ₃ of the curved cavity 3 as the tip of the operating pin 5 approaches or enters the opening end 3D. while being inserted while moving, with the separation or escape from the open end 3D of the tip of the operating pin 5, the said arcuate core pin 10 while swinging along the arcuate axis L ₃ curve Forcing an arc-shaped motion to be pulled out from the cylindrical cavity 3 Since Z is configured to drive the operating pin 5 that reciprocates linearly, it can be easily driven by an actuator that is easily available at a low cost. With such an operating pin 5, pressure loss is caused in the elbow type pipe joint E. Thus, it is possible to reliably form the flow path holes 20 with extremely few.

1 Mold 3 Curved Cavity
3A fold body forming part
3B medium diameter part
3C Large Diameter 3D Open End 5 Actuation Pin 5A Tip
8 Second core pin
Circular hole for guiding 8C core pin
8D guide plate
10 Arc core pin (first core pin)
10A Tip surface
20 Channel hole
21 Inner corner E Elbow fitting (Elbow fitting)
L ₃ Arc-shaped shaft center Z Arc-shaped motion forcing means
K cam mechanism

Claims (4)

In a manufacturing method for manufacturing an elbow pipe joint by injection molding of a thermoplastic resin,
Against curved shape cavity formed in the mold (1) (3), along an arcuate axis of該弯song-like cavity (3) (L _3), arc-shaped core pin of a circular cross section (10) A method for manufacturing a pipe joint, comprising inserting, then performing injection molding, and drawing out along the arcuate axis (L ₃ ) after cooling for a predetermined time. In a manufacturing method for manufacturing an elbow pipe joint by injection molding of a thermoplastic resin,
From the two open ends (3D) (3D) of the cavity (3) to the mold (1) having a curved cavity (3) corresponding to the outer surface shape of the elbow pipe joint, the cross section is circular. The pair of arc-shaped core pins (10) and (10) are inserted along the arc-shaped axis (L ₃ ) of the curved cavity (3), and the tip surfaces of the pair of core pins (10) and (10) ( 10A) (10A) is held in pressure contact, injection molding is performed, and after cooling for a predetermined time, the pair of core pins (10), (10) is connected to the arcuate axis (L) of the curved cavity (3). ₃ ) Pulling out from the open end (3D) (3D) while moving outward along
The longitudinal cross-sectional shape of the inner corner (21) of the flow path hole (20) of the elbow pipe joint (E) is an arc, and the arcuate axis (L ₃ ) of the flow path hole (20). A method of manufacturing a pipe joint, characterized in that all of the cross-sectional shapes orthogonal to () are circular. A mold (1) for molding an elbow pipe fitting (E) by injection of a thermoplastic resin,
While swinging along the arcuate axis (L ₃ ) of the curved cavity (3) formed in the mold (1), insertion into the curved cavity (3) and extraction to the outside are possible. An apparatus for manufacturing a pipe joint comprising an arc-shaped core pin (10) that performs an arc-shaped motion. A mold (1) for molding an elbow pipe joint (E) by injection of a thermoplastic resin is provided. The mold (1) is a curved cavity corresponding to the outer surface shape of the elbow pipe joint (E). (3), and each of the two open ends (3D) and (3D) of the cavity (3) is provided with an actuating pin (5) that can be moved back and forth while being linearly reciprocated. An arcuate core pin (10) having a circular cross section is attached to the tip (5A) of the operating pin (5).
With the approach to entry of the operating pin (5) the opening end of the tip to (3D), the arc-shaped core pin (10) along an arcuate axis of the curved shaped cavity (3) (L ₃₎ The arcuate core pin (10) is inserted into the arcuate axis (L ₃ ) as the tip of the operating pin (5) is separated from or escaped from the open end (3D). ), And an arcuate motion forcing means (Z) that is pulled outward from the curved cavity (3) while swinging along the curved cavity).

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