JP5543012B1 - Pipe-shaped molded body and manufacturing method thereof - Google Patents

Abstract

The present invention provides a pipe-like molded body that can improve airtightness, reduce manufacturing costs, improve reliability, and the like, and a method for manufacturing the same.
A pipe-shaped body made of a first thermoplastic resin divided into a plurality of parts in the circumferential direction is surrounded by a surrounding material made of a second thermoplastic resin. This is a pipe-shaped molded body 1 that is covered from the entire circumference, and thus the pipe-shaped main bodies 2 and 3 are fixed and held in a state assembled in a pipe shape. The pipe-shaped main bodies 2 and 3 have a plurality of boss holes 5 and 6 on the outer periphery, and the boss holes 5 and 6 are secondary molding used when forming the enveloping material 4 made of the second thermoplastic resin. It is a shape corresponding to a pin for fixing a pipe-shaped main body, which is formed in a mold for use in the process, or is disposed so as to be movable in and out in the moving direction of the mold for secondary molding.
[Selection] Figure 1

Description

  The present invention relates to a pipe-shaped molded body that can be used as a piping component, and a method for manufacturing the same.

Conventionally, metal has been used as a pipe used for piping or the like, but recently, resin pipes are often used from the viewpoint of corrosion resistance and weight reduction.
As a resin pipe, for example, a method of continuously producing a hollow molded body by extrusion molding is known. Such a manufacturing method has high production efficiency and is effective for the manufacture of a simple straight pipe. However, a pipe having a curved portion (bent portion, curved portion, etc.) or branch portion cannot be manufactured (obtained) by such extrusion molding.

  As a method of obtaining a resin-made bent tube, after a pair of half-shaped primary molded bodies are manufactured by injection molding, the primary molded bodies are engaged with each other, and another resin is injected into the joint as necessary. For example, there is known a method for obtaining an integrated resin bent tube.

  In addition, after engaging a pair of half-shaped primary molded bodies, the core made of these primary molded bodies is inserted (inserted) into a resin shell molding die, and the resin outer shell portion is formed by injection molding. For example, Patent Documents 1 and 2 disclose a method of obtaining a branched resin pipe having improved hermeticity by forming the shape. In addition, in the manufacturing methods disclosed in these Patent Documents 1 and 2, it is also disclosed that the core is positioned by inserting metal rods at both ends when the core is disposed in the mold. ing.

  Further, in Patent Document 3, both ends are not half-shaped, and the like has a full circumference, while a portion other than both ends is formed with a pair of half-shaped primary molded bodies. After being engaged, each slide core is inserted into both ends (linear portions at both ends) and placed in the mold, and then a resin outer shell is formed by injection molding. A method for obtaining a resin bent tube is disclosed.

  According to the manufacturing methods of these Patent Documents 1 to 3, when the core and the primary molded body are arranged in the mold and the resin for secondary molding is injected, the end of the core and the primary molded body Since the metal rod and slide core are inserted into the core, the core and the end of the primary molded body into which the metal rod and slide core are inserted can be molded in a well-positioned state.

Japanese Patent Laid-Open No. 7-256696 JP-A-8-142114 JP2013-111969A

  However, according to the method of manufacturing a resin pipe having a conventional curved portion (bent portion, curved portion, etc.) or branch portion as disclosed in Patent Documents 1 and 2, a pair of halved primarys When injecting the resin for secondary molding in a state where the molded body is engaged, if the resin is injected under a high pressure or high heat state, the resin for secondary molding flows into the inside from the gap of the engaging portion ( In order to avoid the occurrence of such problems, there are many manufacturing restrictions such as the need to mold in a low pressure state and a relatively low temperature molten state.

  In addition, according to the conventional method for manufacturing a resin pipe having a curved portion as disclosed in Patent Document 3, both ends of the primary molded body into which the slide core is inserted are well positioned. In addition, since there is no joint between the primary molded bodies, there is no problem that the resin for secondary molding flows into the primary molded body. However, in places other than both ends of the pipe (that is, the portion near the center including the bent portion), when resin is injected at a high pressure, there occurs a problem that the resin for secondary molding flows into the inside from the gap of the engaging portion. In order to avoid the occurrence of such problems, there are manufacturing restrictions such as molding in a low-pressure state and a relatively low-temperature molten state, resulting in a decrease in production efficiency.

  In addition, when the resin for secondary molding flows into the inside from the gap of the engaging portion, the resin protrudes into the pipe-shaped molded body to obstruct the flow path, or the disturbance of the flow causes the pipe-shaped molded body to There is a risk that the appearance may be impaired, or the density of the pipe-shaped molded body may become uneven, resulting in a decrease in pipe strength, resulting in a decrease in reliability.

  The present invention solves the above-described problems, and provides a pipe-shaped molded body that can improve airtightness and can reduce manufacturing costs and improve reliability, and a method for manufacturing the same. Objective.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the gist of the present invention is as follows.
(1) A pipe-shaped main body made of a first thermoplastic resin divided into a plurality of parts in the circumferential direction is covered from the entire outer periphery of the pipe-shaped main body by a surrounding material made of a second thermoplastic resin. The pipe-shaped body is fixed and held in a state of being assembled in a pipe shape, and has a plurality of boss holes on the outer periphery of the pipe-shaped body. .
(2) The boss hole is formed in a secondary molding die used when forming the enveloping material made of the second thermoplastic resin, or in the moving direction of the secondary molding die. (1) The pipe-shaped molded product according to (1), wherein the pipe-shaped molded body has a shape corresponding to a pin for fixing the pipe-shaped main body, which is disposed so as to be freely retractable.
(3) The pipe-shaped molded body according to (1) or (2), wherein the pipe-shaped main body has a shape having no branching portion, a bending portion, or a bending portion.
(4) The pipe-shaped molded body according to (1) or (2), wherein the pipe-shaped main body has at least one deformed portion of a branch portion, a curved portion, and a bent portion.
(5) One of the pipe-shaped main bodies has a shape in which at least one end portion has an entire circumference without being divided, and the boss is formed in a portion divided in the circumferential direction in the pipe-shaped main body. A pipe-shaped molded article according to (4), wherein a hole is formed.
(6) The pipe-shaped molded product according to (1) to (5), which is used as a piping component.
(7) The pipe-shaped molded body is used as a piping component, and a nut for connection with another piping component is loosely fitted, and a part of the pipe-shaped main body is not covered with an enveloping material. (1)-(6) pipe-shaped molded object.
(8) A primary molding step of molding a plurality of pipe-shaped main bodies that are divided in the circumferential direction using the first thermoplastic resin, and a plurality of pipe-shaped main bodies in a cavity for secondary molding. Are connected in a pipe-like state, and a plurality of pins for fixing the pipe-like body provided in a posture protruding into the cavity are a plurality of bosses provided on the outer periphery of the pipe-like body. A second thermoplastic resin is formed in a cavity between the sandwiched pipe-shaped body and the secondary molding die, and is sandwiched between secondary molding dies inserted into the holes. And a secondary molding step of molding by enclosing the enveloping material.
(9) One of the pipe-shaped main bodies has a shape in which at least one end portion has an entire circumference without being divided, and in the secondary molding step, the plurality of pins for fixing the pipe-shaped main body include the pins A core pin inserted into each of the plurality of boss holes of the pipe-shaped main body and different from the plurality of pins for fixing the pipe-shaped main body is inserted into the end portion of the shape having the entire circumference, and is inserted into the cavity. The method for producing a pipe-shaped molded article according to (8), wherein an envelope material made of a second thermoplastic resin is introduced and molded.
(10) In the secondary molding step, the coupling nut is disposed in a cavity for secondary molding in a state where the nut for connection is disposed at a location not covered by the surrounding material, and the second thermoplasticity Resin is inject | poured into the said cavity, The manufacturing method of the pipe-shaped molded object of (8), (9) characterized by the above-mentioned.

  According to the present invention, when forming the envelope made of thermoplastic resin, the pipe-shaped main body fixing pin is inserted into the boss hole of the pipe-shaped main body to fix the position of the pipe-shaped main body (that is, positioning). Can). Therefore, when injecting the resin for secondary molding in a state where the pipe-shaped main bodies are engaged with each other, even when the resin is injected in a high pressure or high heat state, it is used for secondary molding from the gap of the engaging portion to the inside. It is possible to reliably prevent the inflow of the resin, and to reduce the manufacturing cost and improve the reliability.

  Furthermore, the pipe-shaped main body made of the first thermoplastic resin is covered from the entire outer periphery of the pipe-shaped main body with the surrounding material made of the second thermoplastic resin in a state where the pipe-shaped main body is securely adhered to the dividing surface without any gap. Since the pipe-shaped body made of the first thermoplastic resin has the same level of durability against external or internal stress as that of the integral pipe-shaped body that is not divided, the resin pipe When a gas or fluid is allowed to flow inside, no gap is generated on the divided surface even by expansion and contraction of the pipe-shaped body with respect to temperature and pressure.

  Further, the plurality of boss holes on the outer periphery of the pipe-shaped main body do not simply cover the surface of the pipe-shaped main body made of the first thermoplastic resin, but the second thermoplastic resin with respect to the concave portion or the convex portion due to the boss hole. Since the pipe-shaped molded body is used as a resin pipe for a long period of time, there is no displacement or dropout of the surrounding material due to expansion and contraction of the pipe-shaped body. The function as a resin pipe can be stably maintained without peeling between the pipe-shaped main body made of one thermoplastic resin and the surrounding material made of the second thermoplastic resin.

  In addition, one of the pipe-shaped main bodies has a shape in which at least one end portion has an entire circumference without being divided, and in the secondary molding step, a plurality of pins for fixing the pipe-shaped main body are formed in the pipe-shaped A core pin that is inserted into each of a plurality of boss holes of the main body and that is different from the plurality of pins for fixing the pipe-shaped main body is inserted into the end of the shape having the entire circumference, and into the second cavity. By allowing the enveloping material made of thermoplastic resin to flow in, the entire end portion of the pipe-shaped main body and the divided portions are positioned well. As a result, when the resin for secondary molding is injected with the pipe-shaped main bodies being engaged with each other, even if the resin is injected under high pressure or high heat, secondary molding is performed from the gap of the engaging portion to the inside. It is possible to more reliably prevent the resin for use from flowing in, and to reduce the manufacturing cost and improve the reliability.

(A) And (b) is a perspective view of the pipe-shaped molded object which concerns on embodiment of this invention, respectively. (A) And (b) is a perspective view of one pipe-shaped main body in the same pipe-shaped molded object, respectively. (A) And (b) is a perspective view of the other pipe-shaped main body in the same pipe-shaped molded object, respectively. It is a perspective view which shows the state which assembled | attached the other pipe-shaped main body to one pipe-shaped main body in the same pipe-shaped molded object. It is a perspective view which shows the state which assembled | attached the other pipe-shaped main body further in the same pipe-shaped molded object. (A) And (b) is a sectional view explaining the process of the manufacturing method of one pipe-shaped main part of the pipe-shaped molded object, (a) shows the state before pouring resin for primary molding, (B) shows a state in which a resin for primary molding is injected. (A) And (b) is sectional drawing explaining the process of the manufacturing method of the other pipe-shaped main body of the same pipe-shaped molded object, respectively, (a) shows the state before inject | pouring resin for primary molding. , (B) shows a state where a resin for primary molding is injected. (A) And (b) is sectional drawing explaining the process of the manufacturing method of the said pipe-shaped molded object, respectively (a) shows the state before injecting resin for secondary molding, (b) The state which inject | poured resin for secondary shaping | molding is shown. It is sectional drawing explaining the process of the manufacturing method of the said pipe-shaped molded object, shows the state which made the upper metal mold | die leave | separate from a lower metal mold | die, and pulled out the core pin from the both ends of a pipe-shaped main body. It is a perspective view explaining the process of the manufacturing method of the pipe-shaped molded object. It is a perspective view of the pipe-shaped molded object which concerns on other embodiment of this invention. It is a perspective view of the nut of the pipe-shaped molded object. It is a perspective view which shows the state which attached the nut to one pipe-shaped main body in the pipe-shaped molded object. It is a perspective view which shows the state which assembled | attached the other pipe-shaped main body to one pipe-shaped main body in the same pipe-shaped molded object.

  1 in FIG. 1 is a pipe-shaped molded body according to an embodiment of the present invention. In this embodiment, the pipe-shaped molded body 1 includes a central portion 1a having a curved portion as a deformed portion whose axis is curved. Both end portions 1b and 1c are deformed pipes having straight pipe portions whose axial centers extend linearly from the end portions of the curved portions. Moreover, in this pipe-shaped molded object 1, the branch part 1d branched to a side is also formed in a part of center part 1a which curves.

  As shown in FIGS. 2 to 4, the pipe-shaped molded body 1 is made of a first thermoplastic resin in which the central portion is divided into a plurality (two in this embodiment) in the circumferential direction. The pipe-shaped main bodies (main body divided bodies) 2 and 3 are structured to be covered from the entire outer periphery of the pipe-shaped main bodies 2 and 3 by the enveloping material 4 made of the second thermoplastic resin. Thereby, the pipe-shaped main bodies 2 and 3 divided | segmented into several with respect to the circumferential direction are fixed and hold | maintained in the state assembled (engaged) in the pipe shape with the surrounding material 4, and the pipe-shaped main body 2, 3 and the surrounding material 4 are integrated. Thus, since the pipe-shaped main bodies 2 and 3 are covered and integrated with the surrounding material 4, the airtightness of the pipe-shaped molded body 1 is improved.

  In this embodiment, one pipe-shaped main body (one main body divided body) 2 has a shape having an entire circumference without dividing both end portions 2b and 2c. On the other hand, the central portion 2a of one pipe-like main body 2 has a so-called halved shape that is divided into two in the circumferential direction, and the other pipe-like main body (the other main body divided body) 3 remains. And is fitted and assembled to the central portion 2a of one pipe-shaped main body while being sandwiched between both end portions 2b and 2c.

  Moreover, the one end part 1b of the pipe-shaped molded object 1 made into the shape which has a perimeter is not covered with the surrounding material 4, and the collar part 1e extended outside is formed in the edge. However, the boundary between the pipe-shaped main body 2 and the pipe-shaped main body 3 is covered with the enveloping material 4. Further, the other end 1c of the pipe-shaped molded body 1 is covered with the enveloping material 4 to form a threaded portion (male threaded portion). Moreover, when the pipe-shaped molded object 1 is used as piping components, for example, it is suitable. However, it is not limited to this.

  Here, as shown in FIGS. 2A, 2B, 3A, and 3B, the center portion 2a of one pipe-shaped main body 2 and the other pipe-shaped main body 3 are described later. As shown, the upper mold 21 and the lower mold 22 for secondary molding that are used when the envelope 4 made of the second thermoplastic resin is used (FIGS. 8A and 8B). ) (See FIG. 9) and a plurality of pipe-shaped body fixing pins 28 and 29 (see FIGS. 8 (a), (b), FIG. 9 and FIG. 10). , 6 are formed. During secondary molding, the pin 29 for fixing the pipe-shaped main body of the upper mold 21 is inserted into the boss hole 6 of the other pipe-shaped main body 3 from above to position the other pipe-shaped main body 3, and The pipe-shaped main body fixing pin 28 of the lower mold 22 is inserted into the boss hole 5 of the one pipe-shaped main body 2 from below so that the one pipe-shaped main body 2 is positioned. Moreover, 5a, 5b, 6a, 6b in FIG. 2 (a), (b), FIG. 3 (a), (b) is formed to project upward or in a family direction, and boss holes 5, 6 are formed. It is a boss part.

  The first thermoplastic resin constituting the pipe-shaped main bodies 2 and 3 is not particularly limited, and examples thereof include polyethylene, polypropylene, ABS resin, polybutylene terephthalate, polyphenylene sulfide, polyvinyl chloride, and polyamide. it can. Especially, since polyphenylene sulfide is excellent in heat resistance and mechanical rigidity, it can be used satisfactorily even when a high-temperature or low-temperature fluid flows inside or when a large force acts from the outside.

  The second thermoplastic resin constituting the envelope member 4 is not particularly limited, but from the viewpoint of adhesion and adhesion between the pipe-like main bodies 2 and 3 and the envelope member 4, the pipe-like main bodies 2 and 3. It is preferable to use the same or the same material as the first thermoplastic resin that constitutes. Furthermore, as the second thermoplastic resin, a so-called hot melt resin selected from any one of a copolyester, a copolyamide, a copolyolefin and the like excellent in adhesiveness and adhesion can be used. . Suitable combinations of the pipe-shaped bodies 2 and 3 and the envelope 4 are polyethylene / copolymerized polyolefin, polypropylene / copolymerized polyolefin, polybutylene terephthalate / copolyester, polyphenylene sulfide / copolyester, polyamide / Copolyamide and the like.

Next, the manufacturing method of the said pipe-shaped molded object 1 is demonstrated.
First, as shown in FIGS. 6 (a), 6 (b), 7 (a), and 7 (b), each of the pipe-like main bodies 2 and 3 whose central portion is divided into two in the circumferential direction is used. Manufacturing (molding) using an injection molding method (primary molding process). This primary molding process will be described. 6 (a), 6 (b), 7 (a) and 7 (b), 11 and 18 are upper molds for primary molding, and 12 and 19 are lower molds for primary molding. The upper molds 11 and 18 for molding and the lower molds 12 and 19 are disposed so that they can be moved up and down relatively. When the upper molds 11 and 18 and the lower molds 12 and 19 are combined, they are used for primary molding. A primary molding cavity (primary resin injection space) 14 into which the resin (first thermoplastic resin) 13 is injected is formed. Further, the upper molds 11 and 18 are formed with gates 15 serving as injection ports for injecting resin into the cavities 14 (the gate 15 is formed only on the lower molds 12 and 19 or the upper molds are formed. 11 and 18 and lower molds 12 and 19). 6 (a) and 6 (b) show a case where the cavity 14 has a shape corresponding to one of the pipe-shaped main bodies 2. In FIGS. 7 (a) and 7 (b), 6 shows a case where the cavity 14 has a shape corresponding to the other pipe-shaped main body 3, and FIGS. 6A and 7A show a state before injecting a resin for primary molding, FIG. 6B and FIG. 7B show a state where a resin for primary molding is injected. As shown in these drawings, the upper molds 11 and 18 and the lower molds 12 and 19 are integrally formed with convex portions and concave portions for forming the boss holes 5 and 6 and the boss holes 5 and 6. .

  Also, 16 in FIGS. 6A and 6B can be withdrawn / withdrawn from the side (in FIGS. 6A and 6B, it can be withdrawn from the left side to the right side of the paper surface), and its tip portion. Is a retractable rod that serves as a core. During primary molding, the retractable rod 16 is plunged into the cavity 14 from the side. Further, reference numeral 17 denotes a retractable rod that can be moved to and from the side (in FIG. 6B, can be moved back and forth from the back side of the drawing), and its tip portion serves as a core. At the time of molding, the retractable rod 17 enters the cavity 14 side from the side. In this embodiment, the case where such a method is used as a method for forming both end portions 2b and 2c having the entire circumference in one pipe-shaped main body 2 is illustrated, but a method other than this method is used. The two end portions 2b and 2c of one pipe-shaped main body 2 may be formed.

  In this configuration, when manufacturing the pipe-shaped main body 2, as shown in FIG. 6A, the upper mold 11 and the lower mold 12 are combined, and the retracting rods 16 and 17 are moved from the side. In a state of being plunged into the cavity 14 side, as shown in FIG. 6B, molten primary molding resin (first thermoplastic resin) 13 is injected through the gate 15 (primary molding step). Then, after the resin 13 for primary molding is cured, the retracting rods 16 and 17 are retracted and the upper mold 11 is separated upward from the lower mold 12 to form a pipe shape as a primary sealing molded body. Take out the body 2. Thereby, the pipe-shaped main body 2 which is a primary sealing molded object can be manufactured favorably.

  Further, as shown in FIG. 7A, an upper mold 18 and a lower mold 19 for primary molding having a cavity (primary resin injection space) corresponding to the other pipe-shaped main body 3 are used. In the same manner as described above, the other pipe-shaped main body 3 is manufactured (molded) using an injection molding method. As in the case of the upper mold 11 and the lower mold 12, a gate 15 for injecting a primary molding resin (first thermoplastic resin) 13 is also provided. However, since the other pipe-shaped main body 3 does not have an entire peripheral portion, in this step, the retracting rods 16 and 17 and the like are not provided, and naturally these components are not retracted.

  Next, as shown in FIG. 4, the manufactured pipe-shaped bodies 2, 3 are engaged (combined) to form a pipe shape, and the entire outer circumference of the pipe-shaped bodies 2, 3 thus formed into a pipe shape is formed. The surrounding material 4 is manufactured (molded) around the circumference using an injection molding method (secondary molding process). This secondary molding process will be described below.

  As shown in FIG. 8 (a), an upper mold 21 and a lower mold 22 for secondary molding are disposed so as to be relatively movable up and down, and between the upper mold 21 and the lower mold 22, When these are combined, a secondary molding cavity (secondary resin injection space) 24 into which a secondary molding resin (second thermoplastic resin) 23 is injected is formed. Further, the upper mold 21 is formed with a gate 25 serving as an injection port for injecting the secondary resin into the cavity 24. The gate 25 may be formed only on the lower mold 22 or may be formed on the upper mold 21 and the lower mold 22.

  The upper mold 21 and the lower mold 22 are arranged in the cavity 24 as holding parts such as pins that can protrude into the cavity 24 from the upper mold 21 and the lower mold 22. In addition to the core pins 26 and 27 that can be protruded from the sides into the end portions of the pipe-shaped main body 2, the pipe-shaped main bodies 2 and 3 disposed in the cavity 24 are respectively vertically moved into the boss holes 5 and 6. A plurality of pipe-shaped main body fixing pins 28 and 29 which can be plunged are provided.

  Then, as shown in FIGS. 8A and 10, core pins 26 and 27 are provided at both ends 2b and 2c of the pipe-like body 2 held in the cavity (secondary resin injection space) 24 for secondary molding. The upper mold 21 and the lower mold 22 are combined and the pipe-shaped body fixing pins 28 and 29 are inserted into the boss holes 5 and 6 of the pipe-shaped bodies 2 and 3. Not only the both end portions 2b and 2c of the main bodies 2 and 3 but also the central portions of the pipe-like main bodies 2 and 3 are held in a positioned state.

  In this state, as shown in FIG. 8B, a secondary molding resin (second thermoplastic resin) 23 is injected into the secondary molding cavity 24 through the gate 25 (secondary molding step). ). Then, as shown in FIG. 9, after the secondary molding resin 23 is cured, the upper mold 21 is separated upward from the lower mold 22, and the pins 28 and 29 for fixing the pipe-shaped body are connected to the pipe. After the core pins 26 and 27 are pulled out from both end portions 2b and 2c of the pipe-shaped main body 2, the enveloping material 4 as a secondary sealing molded body is taken out. Thereby, the pipe-shaped molded object 1 which covered the pipe-shaped main bodies 2 and 3 with the surrounding material 4 which is a secondary sealing molded object is manufactured.

  Here, according to the above embodiment, when forming the envelope 4 made of thermoplastic resin, the pins 28 and 29 for fixing the pipe-shaped main body are inserted into the boss holes 5 and 6 of the pipe-shaped main bodies 2 and 3. By doing so, the positions of the pipe-like main bodies 2 and 3 can be fixed (that is, positioned) very well. Therefore, even when the resin 23 for secondary molding is injected in a state where the pipe-shaped main bodies 2 and 3 are engaged with each other, even when this resin is injected at a high pressure or a high heat state, the inner portion of the engagement portion is not removed. Therefore, it is possible to reliably prevent the secondary molding resin 23 from flowing in, and to reduce the manufacturing cost and improve the reliability.

  Further, the end portions 2b and 2c of one pipe-shaped main body 2 are formed in a shape having an entire circumference without being divided, and in the secondary molding step, the pins 28 and 29 for fixing the pipe-shaped main body 2 are connected to the pipe-shaped main body 2. The core pins 26 and 27, which are inserted into the three boss holes 5 and 6, respectively, and can be freely withdrawn from the side, are inserted into the end portions 2b and 2c of the pipe-like main body 2, and are inserted into the cavity 24. Since the enveloping material made of the second thermoplastic resin 23 is allowed to flow, the entire ends of the pipe-like main bodies 2 and 3 and the central portion divided vertically are positioned well. As a result, even when the resin 23 for secondary molding is injected with the pipe-shaped main bodies 2 and 3 engaged with each other, even when the resin is injected at a high pressure or a high heat state, the internal portion of the pipe-shaped main bodies 2 and 3 is inserted from the gap of the engaging portion. In addition, it is possible to more reliably prevent the secondary molding resin 23 from flowing in, and to reduce the manufacturing cost and improve the reliability.

  That is, in this case, when the resin 23 for secondary molding flows into the inside from the gap between the engaging portions of the pipe-shaped main bodies 2 and 3, the resin protrudes into the pipe-shaped molded body 1, so that the flow path is formed. Although there is a risk that the appearance of the pipe-shaped molded body 1 may be impaired due to disturbance or flow disturbance, or the density of the pipe-shaped molded body 1 may be uneven and the strength of the pipe may be decreased. According to the present invention, it is possible to surely prevent such a problem from occurring, so that the flow path is not hindered, a good appearance can be maintained, and a pipe-shaped molded article having good pipe strength. 1 can be obtained (manufactured).

  Further, the pipe-shaped main bodies 2 and 3 made of the first thermoplastic resin are in close contact with the dividing surface without gaps, and the pipe-shaped main bodies 2 and 3 are surrounded by the envelope 4 made of the second thermoplastic resin. Since the structure can be covered from the entire outer periphery, the pipe-shaped main bodies 2 and 3 made of the first thermoplastic resin are resistant to external or internal stresses at the same level as an integral pipe-shaped main body that is not divided. When a gas or fluid is flowed as a resin pipe, there is no gap on the split surface even when the pipe-like main bodies 2 and 3 expand and contract with respect to temperature and pressure.

  Further, the plurality of boss holes 5, 6 provided on the outer circumferences of the pipe-shaped bodies 2, 3 do not simply cover the surface of the pipe-shaped bodies 2, 3 made of the first thermoplastic resin, but are formed by the boss holes 5, 6. Even when the obtained pipe-shaped molded body 1 is used as a resin pipe for a long period of time because it is arranged as the envelope 4 in a state where the second thermoplastic resin is engulfed in the concave portion or the convex portion, the pipe-shaped main body The expansion and contraction of 2 and 3 does not cause displacement or dropout of the enveloping material, and there is no separation between the pipe-shaped main bodies 2 and 3 made of the first thermoplastic resin and the enveloping material 4 made of the second thermoplastic resin. The function as a resin pipe can be stably maintained.

  In the above-described embodiment, the case where the pins 28 and 29 for fixing the pipe-shaped main body are provided on the upper mold 21 and the lower mold 22 for secondary molding (formed integrally) has been described. However, the present invention is not limited to this, and the pin for fixing the pipe-shaped main body may be disposed so as to be freely retractable in the moving direction of the secondary molding die.

  Moreover, in this Embodiment, said 2nd thermoplastic resin as a base material of the enveloping material 4 is more excellent in adhesiveness (adhesion) than a general thermoplastic resin, and can be injection-molded at low temperature. A thermoplastic resin, also called a hot melt resin, is used. For example, in the case of a general thermoplastic resin, the injection molding pressure is 50 MPa to 200 MPa, but the injection molding pressure of the thermoplastic resin of the present embodiment is less than 50 MPa, and a pipe shape is used while filling the sealing material (enveloping material 4). There is little possibility of destroying the main bodies 2 and 3.

  According to the said manufacturing method, since the pipe-shaped main bodies 2 and 3 are comprised from resin divided | segmented into plurality with respect to the circumferential direction, they can be manufactured at low cost by the injection molding method etc. Further, the envelope 4 made of resin covering the pipe-like main bodies 2 and 3 can also be manufactured at low cost by an injection molding method or the like. In addition, since the pipe-like main bodies 2 and 3 are covered from the entire circumference of the outer periphery by the enveloping material 4 made of resin, the enveloping material made of resin is not lowered due to heat escaping from the gaps of the heat insulating material. 4 does not come off from the pipe-shaped main bodies 2 and 3, and good heat insulation can be maintained. Moreover, this pipe-shaped molded object 1 can be used suitably as piping components, such as a water pipe, hot water supply, and air-conditioning equipment piping.

  In the above manufacturing method, the second thermoplastic resin is used as the resin used for the enveloping material 4. Unlike the case where the second thermoplastic resin is manufactured by potting using a thermosetting resin (epoxy resin), a relatively short time is required even when the molten thermoplastic resin is cooled and solidified. Time required for the manufacturing process can be reduced, and work efficiency is improved.

  Further, a second thermoplastic resin that can be injection-molded at a low temperature, which is also referred to as a so-called hot melt resin, may be used as the surrounding material 4. Can be molded. Thereby, the damage to the pipe-shaped main bodies 2 and 3 by the heat can be prevented.

  Moreover, in the said embodiment, the pipe-shaped molded object 1, ie, the pipe-shaped main bodies 2 and 3, and the surrounding material 4, the case where the branch part (in this embodiment bifurcated shape part) 1d is provided is described. However, it is needless to say that the above-described configuration and manufacturing method can be used for those that do not have the branching portion 1d.

Further, an external fitting member such as a connecting nut 51 as shown in FIG. 12 may be externally fitted to the pipe-shaped molded body 1 of the above-described embodiment (see FIG. 11).
The manufacturing method of this pipe-shaped molded body 1 will be described. As shown in FIG. 13, first, a nut 51 is inserted into the single pipe-shaped main body 2 from the other end 2c, and the nut 51 is moved around the entire circumference. And is disposed at the position of one end 1b of the pipe-shaped molded body 1 that is not covered with the enveloping material 4. Thereafter, the pipe-like main bodies 2 and 3 are engaged (combined) to form a pipe shape (see FIG. 14) by a process similar to that of the above-described embodiment, and other than one end 1b of the pipe-like main body 2 The part is molded so as to be covered with the surrounding material 4. In addition, after molding, the nut 51 is configured not to come off from the pipe-shaped molded body 1 by the flange 1e formed on the edge of the one end 1b of the pipe-shaped main body 2 and the surrounding material 4, the boss portion, the branching portion, etc. Has been.

  Thus, according to the above manufacturing method, even when an external fitting member such as a connecting nut 51 is externally fitted, as described above, there is almost no increase in the manufacturing process, and relatively inexpensively. It is possible to manufacture a pipe-shaped molded body 1 in which an outer fitting member such as the nut 51 is fitted. The outer fitting member may be other than the connecting nut 51 and can be manufactured by the same manufacturing method.

  In the above-described embodiment, the case of the pipe-shaped molded body 1 having a deformed portion including a curved portion or a branched portion at the center has been described. However, the present invention is not limited to this, and a bent portion can be formed by a similar manufacturing method. It is possible to manufacture or obtain a pipe-shaped molded body having a deformed portion such as a pipe-shaped molded body having a shape that does not have any branch portion, curved portion, or bent portion. It is also possible to do.

1 Pipe-shaped molded body 2 Pipe-shaped main body (main body divided body)
3 Pipe-shaped body (divided body)
4 Enclosure 5, 6 Boss hole 5a, 5b, 6a, 6b Boss part 11, 18 Upper mold (for primary molding)
12, 19 Lower mold (for primary molding)
13 Primary molding resin (first thermoplastic resin)
14 Cavity (Primary resin injection space)
15, 25 Gate 16, 17 Retracting rod 21 Upper mold (for secondary molding)
21a, 22a Pin (for fixing pipe-shaped body)
22 Lower mold (for secondary molding)
23 Resin for secondary molding (second thermoplastic resin)
24 cavity (secondary resin injection space)
26, 27 Core pins 28, 29 Pins for fixing the pipe-shaped main body 51 Nut (outer fitting member)

Claims (10)

A pipe-shaped main body made of a first thermoplastic resin divided into a plurality of parts in the circumferential direction is covered from the entire outer periphery of the pipe-shaped main body by an enveloping material made of a second thermoplastic resin. A pipe-shaped molded body which is fixed and held in a state where the main body is assembled in a pipe shape, and has a plurality of boss holes on the outer periphery of the pipe-shaped main body.   The boss hole is formed in a secondary molding die used when forming an enveloping material made of the second thermoplastic resin, or can be freely moved in and out in the moving direction of the secondary molding die. The pipe-shaped molded body according to claim 1, wherein the pipe-shaped molded body has a shape corresponding to a pin for fixing the pipe-shaped main body.   The pipe-shaped molded body according to claim 1 or 2, wherein the pipe-shaped main body has a shape that does not include any of a branch portion, a curved portion, and a bent portion.   The pipe-shaped molded body according to claim 1 or 2, wherein the pipe-shaped main body has at least one deformed portion of a branch portion, a curved portion, and a bent portion.   One of the pipe-shaped main bodies has a shape in which at least one end portion has an entire circumference without being divided, and the boss hole is formed in a portion divided in the circumferential direction of the pipe-shaped main body. The pipe-shaped molded product according to claim 4, wherein the molded product is a pipe-shaped product.   It is used as piping parts, The pipe-shaped molded object of any one of Claims 1-5 characterized by the above-mentioned.   The pipe-shaped molded body is used as a piping component, and a nut for connection with another piping component is loosely fitted, and a part of the pipe-shaped main body is not covered with an enveloping material. Item 7. The pipe-shaped molded article according to any one of Items 1 to 6.   A primary molding step of molding each pipe-shaped body divided into a plurality of circumferential directions using the first thermoplastic resin, and the plurality of pipe-shaped bodies are engaged in a cavity for secondary molding. A plurality of pins for fixing the pipe-shaped main body arranged in a pipe-like state and projecting into the cavity, respectively, in a plurality of boss holes provided in the outer peripheral portion of the pipe-shaped main body. An enveloping material made of a second thermoplastic resin is inserted in a cavity between the sandwiched pipe-shaped main body and the mold for secondary molding in a state where the mold is clamped by a mold for secondary molding in the inserted state. A method of manufacturing a pipe-shaped molded body, comprising: a secondary molding step of molding by inflowing.   One of the pipe-shaped bodies has a shape in which at least one end portion is not divided and has a whole circumference, and in the secondary molding step, a plurality of pins for fixing the pipe-shaped body are the pipe-shaped body. A core pin inserted into each of the plurality of boss holes and different from the plurality of pins for fixing the pipe-shaped body is inserted into the end of the shape having the entire circumference, and the second heat 9. The method for manufacturing a pipe-shaped molded body according to claim 8, wherein the envelope member made of a plastic resin is flown into the molded body.   In the secondary molding step, an outer fitting member such as a connecting nut is disposed in a cavity for secondary molding in a state where the outer fitting member is disposed at a location not covered by the surrounding material, The method for producing a pipe-shaped molded product according to claim 8 or 9, wherein a thermoplastic resin is injected into the cavity.

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