JP2012213919A - Method of manufacturing tubular hollow molding and mold - Google Patents

Abstract

A tubular hollow molded article manufacturing method and mold capable of efficiently and easily producing a tubular hollow molded article having different diameter portions and different inner diameters of hollow inner peripheral surfaces at different diameter portions. To do.
A method for manufacturing a tubular hollow molded article using a molding die 10 for molding a tubular hollow molded article 60 having a large-diameter portion having a hollow inner peripheral surface whose diameter is larger than a reference hollow inner peripheral surface at an end. , The core 20 having the floating core 50 held on the cavity 13 side of the pressurizing port 34 that forms the large-diameter portion between the cavity surface and communicates the cavity 13 and the outside of the mold 10 is formed in the cavity 13. At one end, the mold 10 is clamped, and the cavity 13 is filled with the molten material, and then the floating core 50 is extruded into the molten material by the pressurized fluid that is press-fitted from the pressurized port 34 along the cavity 13. It advances and shape | molds the reference | standard hollow inner peripheral surface of the tubular hollow molded product 60. FIG.
[Selection] Figure 3

Description

  The present invention relates to a method for manufacturing a tubular hollow molded article and a mold, and more particularly, to a method for manufacturing a tubular hollow molded article and a mold for manufacturing a tubular hollow molded article made of resin.

  Conventionally, in the case of manufacturing a tubular hollow molded product made of resin, a first mold and a second mold that are clamped together are provided, and the first mold and the second mold are shaped along the outer peripheral surface of the tubular hollow molded product. It is known that it is manufactured by an injection molding method or the like using a mold in which a cavity is formed.

  Patent Document 1 discloses a method for producing a tubular hollow molded article, in which a long pipe product as a tubular hollow molded article is produced by an injection molding method using a mold. The manufacturing method of the tubular hollow molded article disclosed in Patent Document 1 will be described with reference to FIGS. 10 (a) and 10 (b).

  As shown in FIG. 10A, the mold 100 includes a lower mold 101 and an upper mold 102, and a cavity surface is formed on each of the lower mold 101 and the upper mold 102 along the outer peripheral surface of the long pipe product. The cavity 103 is formed in a state where the lower mold 101 and the upper mold 102 are clamped together. The upper mold 102 is formed with an injection port (not shown) through which the molten resin m is injected into the cavity 103. A pressurization port 103 a that communicates with the outside of the mold 100 is formed at one end of the cavity 103 of the mold 100, and a discharge port 103 b that communicates with the outside of the mold 100 is formed at the other end of the cavity 103. . A spherical floating core 105 is disposed on the pressure port 103a side, and a molten resin tray 104 is provided on the discharge port 103b side.

  First, the molten resin m is injected into the cavity 103 from the injection port of the upper mold 102. The molten resin m injected into the cavity 103 is gradually cooled and hardened from the outer surface side.

  At this time, as shown in FIG. 10B, the molten resin m is in an uncured state, and the floating core 105 disposed in the pressure port 103a is centered along the cavity 103 of the molten resin m whose viscosity is still low. It pushes in toward the part with pressurized fluid.

  The pushed floating core 105 travels in the molten resin m having a relatively low viscosity from the pressurization port 103 a side to the discharge port 103 b side of the cavity 103, and the molten resin m on the front side in the traveling direction passes through the cavity 103. Excess molten resin m is pushed out from the discharge port 103b to the molten resin tray 104 while being pressed against the cavity surface side. Thereby, the long pipe-shaped resin molded product M is shape | molded. Thereafter, a pressure holding process, a cooling process, and a mold opening process are sequentially performed to form a long pipe product.

Japanese Patent Publication No. 7-20646

  For example, as shown in FIG. 11 (a), there is a large-diameter portion 110b at the end of a thin pipe body portion 110a corresponding to the intermediate portion, and the hollow inner peripheral surface 110c of the large-diameter portion 110b is a reference hollow of the pipe body portion 110a. There is a pipe product 110 formed with a diameter larger than the inner peripheral surface.

  However, when such a pipe product 110 is to be manufactured by the method for manufacturing a tubular hollow molded article disclosed in Patent Document 1, as shown in FIG. The pipe product 120 is manufactured in which the hollow inner peripheral surface 120c having the same diameter as the reference hollow inner peripheral surface is continuously formed over the pipe main body portion 120a and the large diameter portion 120b.

  Therefore, in the method for manufacturing a tubular hollow molded article of Patent Document 1, it is impossible to mold a hollow inner peripheral surface having an inner diameter corresponding to a change in the cross-sectional shape like the pipe product 110 having a different inner diameter.

  Accordingly, an object of the present invention made in view of such points is to provide a tubular hollow molded article that can efficiently and easily produce a tubular hollow molded article having a hollow inner circumferential surface having a diameter different from that of the reference hollow inner circumferential surface. It is in providing a manufacturing method and a shaping | molding die.

  The method for manufacturing a tubular hollow molded article according to the first aspect of the present invention for solving the above-described problem is a tubular tube having a large-diameter portion at the end portion having a hollow inner peripheral surface expanded in diameter relative to a reference hollow inner peripheral surface. Cavity surface for molding the large-diameter portion in the cavity in a method for manufacturing a tubular hollow molded article using a molding die that molds a hollow molded article and has a cavity extending in an axial shape with both ends open to the outside A pressurizing port is formed to protrude from the cavity through the gap and form the large diameter portion between the cavity surface and the cavity and the outside of the mold. A mold clamping step in which a core having a floating core held on the cavity side of the pressure port is attached to one end of the cavity and the mold is clamped; and a resin material is placed in the cavity A filling material filling step, and after the resin material is filled into the cavity, the floating core is pushed out into the resin material by a pressurized fluid that is press-fitted from the pressure port, and is advanced along the cavity And a pressurizing step of forming the reference hollow inner peripheral surface of the tubular hollow molded product and discharging the floating core from the other end of the cavity.

  According to the present invention, a large hollow inner peripheral surface that is spaced apart from the cavity surface and protrudes into the cavity through a gap and is expanded with respect to the reference hollow inner peripheral surface of the tubular hollow molded article. A core for molding the diameter part is attached to one open end of the cavity, the mold is clamped and the cavity is filled with a resin material, and the hollow inner diameter is different from the inner diameter of the reference hollow inner peripheral surface. A large diameter portion having a peripheral surface is formed.

  On the other hand, when a pressurized port is formed to communicate the cavity and the outside of the mold, and when a pressurized fluid is injected from the pressurized port of the core in which the floating core is held on the cavity side of the pressurized port, the floating core is The reference hollow inner peripheral surface is molded by being extruded into the resin material and proceeding along the cavity.

  Accordingly, by using a hollow hollow molded product having a different inner diameter between the reference hollow inner peripheral surface and the hollow inner peripheral surface of the large-diameter portion by using a core attached to the end of the cavity and a floating core held by the core. Efficient and easy production of the tubular hollow molded article is realized.

  The method for manufacturing a tubular hollow molded article according to the second aspect of the present invention has a first large diameter portion and a second large diameter portion having a hollow inner peripheral surface whose diameter is expanded with respect to a reference hollow inner peripheral surface at both ends. In the method for manufacturing a tubular hollow molded article using a molding die for forming a tubular hollow molded article and having a cavity extending in an axial shape whose both ends are open to the outside, the first large diameter portion in the cavity is molded. A pressurizing port that is spaced apart from the cavity surface that protrudes into the cavity through a gap and molds the first large diameter portion between the cavity surface and communicates the cavity and the outside of the mold. A cavity that is formed and a first core having a floating core held on the cavity side of the pressure port is attached to one end of the cavity, and the second large-diameter portion in the cavity is molded. A discharge port is formed that is spaced from the surface and protrudes into the cavity through a gap to form the second large diameter portion between the cavity surface and communicate the cavity and the outside of the mold. A mold clamping step of clamping the molding die by attaching a second core to the other end of the cavity, a material filling step of filling the cavity with a resin material, and the cavity filled with the resin material Later, the floating core is pushed into the resin material by a pressurized fluid that is press-fitted from the pressurized port, and is advanced along the cavity to mold the reference hollow inner peripheral surface of the tubular hollow molded article, and then the discharge And a pressurizing step for discharging the floating core from the port.

  According to the present invention, there is provided the first hollow inner peripheral surface which is spaced apart from the cavity surface and protrudes into the cavity through the gap and is expanded with respect to the reference hollow inner peripheral surface of the tubular hollow molded article. The first core and the second core that mold the one large diameter portion and the second large diameter portion are attached to one end and the other end of the cavity, the mold is clamped, and the resin is placed in the cavity. The material is filled, and a first large diameter portion and a second large diameter portion having a hollow inner peripheral surface having an inner diameter different from the inner diameter of the reference hollow inner peripheral surface are formed.

  On the other hand, when a pressurized port is formed to communicate the cavity and the outside of the mold and a pressurized fluid is injected from the pressurized port of the first core in which the floating core is held on the cavity side of the pressurized port, The core is extruded into the resin material and proceeds along the cavity, and the floating core is discharged from the discharge port formed in the second core to form the reference hollow inner peripheral surface.

  Accordingly, the first hollow core and the first core mounted on one end of the cavity are tubular hollow molded products having different inner diameters between the reference hollow inner peripheral surface and the hollow inner peripheral surfaces of the first large diameter portion and the second large diameter portion. By using the floating core held by the core and the second core attached to the other end of the cavity, efficient and easy manufacture of the tubular hollow molded article is realized.

  According to a third aspect of the present invention, there is provided a molding die according to the invention, wherein both ends are opened to the outside and a resin material is filled in a cavity extending in a shaft shape, and the pressurized fluid is press-fitted into the resin material from the pressure port. The floating core is pushed out by the advancing along the cavity to form the reference hollow inner peripheral surface of the tubular hollow molded article, and the floating core is discharged from the other end of the cavity. In a molding die for forming a tubular hollow molded article having a large-diameter portion having a hollow inner peripheral surface whose diameter is increased with respect to a peripheral surface at an end portion, the mold in the cavity is attached to at least one end portion of both ends of the cavity. The large diameter portion is separated from the cavity surface for molding the large diameter portion and protrudes into the cavity through a gap to mold the large diameter portion between the cavity surface and the cavity The mold and the external is pressure port that communicates with forming and characterized in that it comprises a core for holding the floating core to the cavity side of the pressurizing port.

  According to this invention, since the core for forming the large diameter portion having the hollow inner peripheral surface whose diameter is expanded with respect to the reference hollow inner peripheral surface of the tubular hollow molded product is provided, the cavity is opened in the cavity. The large-diameter portion having a hollow inner peripheral surface having an inner diameter different from the inner diameter of the reference hollow inner peripheral surface is formed by attaching to one end portion and clamping the mold and filling the cavity with a resin material.

  On the other hand, the core has a pressurization port that communicates the cavity and the outside of the mold and pressurizes the pressurized fluid. Therefore, the floating core disposed on the cavity side of the pressurization port is made of resin. The reference hollow inner peripheral surface is formed by being extruded into the material and proceeding along the cavity.

  Accordingly, by using a hollow hollow molded product having a different inner diameter between the reference hollow inner peripheral surface and the hollow inner peripheral surface of the large-diameter portion by using a core attached to the end of the cavity and a floating core held by the core. Efficient and easy production of the tubular hollow molded article is realized.

  According to a fourth aspect of the present invention, there is provided a molding die according to the third aspect, wherein the core includes a base portion attached to an end portion of the cavity and a state in which the base portion is attached to the cavity. A main body portion that is spaced apart from the cavity surface of the cavity and protrudes into the cavity through a gap and that forms the large diameter portion with the cavity surface, and the main body portion extends from the base portion to the main body portion. A pressure port penetrating along the axial direction of the pressure port, and an inner peripheral surface formed on the main body side of the pressure port to fit and hold the floating core.

  The present invention specifically clarifies the structure of the core according to claim 3, and the core attached to the open end of the cavity has a large diameter portion between the cavity surface. A floating core that molds the reference hollow inner peripheral surface is held on the inner peripheral surface of the main body portion side of the pressure port that has the main body portion to be molded and penetrates along the axial direction of the main body portion. By using such a simple core, it is possible to mold the hollow inner peripheral surface of the large diameter portion and to mold the reference hollow inner peripheral surface.

  According to a fifth aspect of the present invention, there is provided a molding die according to the invention, wherein both ends are opened to the outside and a resin material is filled in a cavity extending in a shaft shape, and the pressurized fluid is press-fitted into the resin material from the pressure port. The floating core is pushed out and proceeds along the cavity to form the reference hollow inner peripheral surface of the tubular hollow molded article, and the floating core is discharged from the discharge port to the reference hollow inner peripheral surface. In a molding die for forming a tubular hollow molded product having a first large diameter portion and a second large diameter portion at both ends having a hollow inner peripheral surface expanded in diameter, the mold in the cavity is attached to one end portion of the cavity. The first large-diameter portion is separated from the cavity surface where the first large-diameter portion is formed, protrudes into the cavity via a gap, and the first large-diameter portion is formed between the cavity surface and the cavity. And a pressure port that communicates with the outside of the mold, a first core that holds the floating core on the cavity side of the pressure port, and a second core that is attached to the other end of the cavity. The second large diameter portion is spaced apart from the cavity surface for forming the second large diameter portion and protrudes into the cavity through a gap to form the second large diameter portion between the cavity surface and the cavity and the outside of the mold And a second core in which a discharge port communicating with the second core is formed.

  According to the present invention, the first core and the second medium for forming the first large diameter portion and the second large diameter portion having the hollow inner peripheral surface expanded in diameter with respect to the reference hollow inner peripheral surface of the tubular hollow molded product. Since the core is provided, these cores are attached to the open end and the other end of the cavity, the mold is clamped, and the cavity is filled with the molten material, and the inner diameter of the reference hollow inner peripheral surface The first large-diameter portion and the second large-diameter portion having hollow inner peripheral surfaces with different inner diameters are formed.

  On the other hand, the first core is formed with a pressurization port that communicates the cavity and the outside of the mold and into which the pressurized fluid is press-fitted, so that the floating core disposed on the cavity side of the pressurization port Is extruded into the resin material and proceeds along the cavity, and the floating core is discharged from the discharge port formed in the second core to form the reference hollow inner peripheral surface.

  Accordingly, tubular hollow molded products having different inner diameters between the reference hollow inner peripheral surface and the first large diameter portion and the second large diameter portion are held by the first core and the first core that are attached to one end of the cavity. By using the floating core and the second core attached to the other end of the cavity, efficient and easy manufacture of a tubular hollow molded product is realized.

  The mold according to the invention of claim 6 is the mold according to claim 5, wherein the first core has a base portion attached to one end portion of the cavity, and the base portion attached to the cavity. A body portion that is spaced apart from the cavity surface of the cavity in a state and protrudes into the cavity through a gap and that forms the first large diameter portion with the cavity surface, and extends from the base portion to the body portion A pressurizing port penetrating along the axial direction of the main body part, and an inner peripheral surface formed on the main body part side of the pressurizing port to fit and hold the floating core, The two cores are attached to the other end of the cavity, and protrude from the cavity surface of the cavity in the state where the base is attached to the cavity through the gap into the cavity. A main body for forming the second large-diameter portion between the cavity surface and a discharge port penetrating with the same diameter as the floating core along the axial direction of the main body from the base to the main body. , Comprising.

  In the present invention, the configuration of the core according to claim 5 is clarified specifically, and the first core and the second core are respectively mounted on the open end and the other end of the cavity. However, a 1st large diameter part and a 2nd large diameter part are shape | molded between cavity surfaces. In addition, a floating core for forming the reference hollow inner peripheral surface is held in the main body portion of the first core, and a discharge port for discharging the remaining resin material is formed in the main body portion of the second core. . Therefore, by using the first core and the second core having such a simple configuration, the hollow inner peripheral surface of the first large diameter portion and the second large diameter portion are molded and the reference hollow inner peripheral surface is molded. Can do.

  According to the present invention, the reference hollow inner peripheral surface and the large diameter are formed by a simple configuration in which the core having the floating core pushed out by the resin material filled in the cavity is held in the molding die while the large diameter portion is molded. A tubular hollow molded product having an inner diameter different from that of the hollow inner peripheral surface of the portion can be easily formed.

It is a figure explaining the outline of the shaping | molding die concerning this Embodiment. (A) is the II sectional view taken on the line of FIG. 1, (b) is the II-II sectional view taken on the line of FIG. Similarly, it is a figure explaining the shaping | molding die concerning this Embodiment. Similarly, it is a figure explaining the outline of the pressurization process concerning this embodiment. Similarly, it is a figure explaining the outline of the pressurization process concerning this embodiment. Similarly, it is a figure explaining the outline of the pressurization process concerning this embodiment. Similarly, it is a figure explaining the outline of the pressurization process concerning this embodiment. It is a figure explaining the outline of a tubular hollow molded article. Similarly, it is a figure explaining the outline of a tubular hollow molded article. It is a figure explaining the outline of the manufacturing method of the conventional tubular hollow molded article. It is a figure explaining the outline of a hollow molded article.

  Next, an embodiment of the present invention will be described with reference to FIGS. The tubular hollow molded article manufactured by the tubular hollow molded article manufacturing method and the mold according to the present embodiment has a pipe main body 62 that has a reference hollow inner peripheral surface and serves as an intermediate part as shown in FIG. And the first large-diameter portion 61 and the second large-diameter portion 63 having a hollow inner peripheral surface whose diameter is larger than that of the reference hollow inner peripheral surface of the pipe main body portion 62, and are formed in a substantially U shape in plan view. The case of the long pipe product 60 will be described as an example.

  First, an outline of a mold used in the method for manufacturing a tubular hollow molded article according to the present embodiment will be described.

  1A and 1B are diagrams for explaining an outline of the mold 10, FIG. 2A is a cross-sectional view taken along the line II in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a diagram illustrating the mold 10. As shown in the figure, the mold 10 is mounted on the lower mold 11 and the upper mold 12 that moves in the mold clamping direction and the mold opening direction with respect to the lower mold 11, and the first mold 10 is mounted between the lower mold 11 and the upper mold 12. A core 30 and a second core 40 are provided. A spherical floating core 50 is attached to the first core 30. The floating core 50 is formed so that its diameter is substantially the same as the inner diameter of the reference hollow inner peripheral surface of the pipe main body 62 of the long pipe product 60 to be molded.

  Each of the lower mold 11 and the upper mold 12 is formed with a cavity surface along the outer peripheral surface of the long pipe product 60. This cavity surface is formed continuously from a first cavity surface 13a and a first cavity surface 13a that are continuous in a half-like shape following the outer peripheral surface of the first large-diameter portion 61, that is, a semicircular cross-section, and a pipe body portion. A second cavity surface 13b formed in a shape following the outer peripheral surface of 62, and a third cavity formed continuously from the second cavity surface 13b and formed in a shape following the outer peripheral surface of the second large-diameter portion 63 It has surface 13c.

  The first cavity surface 13a is formed with a halved first core mounting surface 14a which is continuous from the first cavity surface 13a and communicates with the outside of the molding die 10, and the third cavity surface 13c has this A half-shaped second core mounting surface 15a that is continuous from the third cavity surface 13c and communicates with the outside of the mold 10 is formed.

  In the lower mold 11 and the upper mold 12 having such a configuration, when the upper mold 12 is clamped with respect to the lower mold 11, the first cavity 13A is formed by the first cavity surface 13a, and the second cavity surface 13b is the second cavity. A cavity 13B is formed, and a third cavity 13C is formed by the third cavity surface 13c. The first cavity 13A, the second cavity 13B, and the third cavity 13C constitute a cavity 13 extending in an axial shape, and the first core mounting surface formed in a half shape on the lower mold 11 and the upper mold 12 14a constitutes a cylindrical first core mounting portion 14 which is continuously open to the outside at one end portion of the cavity 13, and is formed in a half shape in the lower die 11 and the upper die 12. The mounting surface 15a constitutes a second core mounting portion 15 that is continuously open to the outside at the other end of the cavity 13.

  The upper mold 12 is formed with an injection port 12 a that communicates with the second cavity 13 </ b> B of the cavity 13 and injects molten resin m, which is a resin material, into the cavity 13.

  Next, the first core 30 and the second core 40 will be described. As shown in FIG. 2A, the first core 30 protrudes from a disk-shaped base 31 that fits into the first core mounting portion 14 of the molding die 10, a substantially central portion of the base 31, and the first core 30. It has a substantially cylindrical main body 32 that follows the shape of the hollow inner peripheral surface of the large diameter portion 61 and is integrally formed. The main body portion 32 is formed with a distal end portion 32 a that gradually decreases in diameter as the distance from the base portion 31 increases.

  The first core 30 is formed with a pressurizing port 34 penetrating along the axial direction of the main body portion 32 from the base portion 31 to the distal end portion 32 a of the main body portion 32. The pressurizing port 34 communicates with the outside of the mold 10 in a state where the first core 30 is mounted on the mold 10, and the first port 34 a and the first port 34 a are formed on the same axis as the main body 32. And a second port 34b whose diameter is enlarged from the first port 34a on the tip 32a side. A spherically formed floating core 50 is fitted and held on the inner peripheral surface 34c of the second pressurizing port 34b of the first core 30. When the first core 30 is attached to the mold 10 in this state, the cavity 13 and the outside of the mold 10 are not in communication.

  As shown in FIG. 2B, the second core 40 protrudes from a disk-shaped base 41 that fits into the second core mounting portion 15 of the mold 10, a substantially central portion of the base 41, and the second core 40. It has a cylindrical main body portion 42 that follows the shape of the hollow inner peripheral surface of the large diameter portion 63 and is integrally formed. The main body portion 42 is formed with a distal end portion 42 a that gradually decreases in diameter as the distance from the base portion 41 increases.

  The second core 40 is formed with a discharge port 44 penetrating along the axial direction of the main body 42 from the base 41 to the distal end portion 42 a of the main body 42. The discharge port 44 communicates with the outside of the mold 10 in a state where the second core 40 is mounted on the mold 10, has the same diameter as the floating core 50, and is coaxial with the main body 42. It is formed.

  Next, a method for manufacturing the tubular hollow molded article according to the present embodiment will be described with reference to FIGS. 4 to 7 and FIGS. 2 and 3 again. 4-7 is a figure explaining the outline of a pressurization process.

  In this embodiment, the long pipe product 60 made of resin follows the final shape of the product by sequentially performing a mold clamping process, a material filling process, a pressurizing process, a pressure holding process, a cooling process, and a mold opening process. It is molded into a different shape.

  As shown in FIG. 3, the upper mold 12 is moved in the mold clamping direction indicated by the arrow A with respect to the lower mold 11, and the cavities 13 are configured by overlapping each other.

  Subsequently, the first core 30 and the second core 40 to which the floating core 50 is attached are attached to the mold 10. First, when the base portion 31 of the first core 30 is attached to the first core attachment portion 14, the main body portion 32 is separated from the first cavity surface 13a of the first cavity 13A as shown in FIG. It enters into the first cavity 13A through the gap and protrudes.

  Next, when the base portion 41 of the second core 40 is attached to the second core attachment portion 14, the main body portion 42 is separated from the third cavity surface 13c of the third cavity 13C as shown in FIG. It enters into the third cavity 13C through the gap and protrudes.

  Thereafter, a molten resin tray (not shown) is attached to the outside of the mold 10 communicating with the discharge port 44 of the second core 40.

  In this way, the lower mold 11 and the upper mold 12 are overlapped, and the first core 30 and the second core 40 are mounted on the first core mounting portion 14 and the second core mounting portion 15, and the second center The mold clamping process is completed by attaching a molten resin tray to the outside of the mold 10 communicating with the discharge port 44 of the child 40.

  After the mold clamping process, the process proceeds to the material filling process. In this material filling process, the molten resin m is filled into the cavity 13 by injecting the molten resin m into the cavity 13 from the injection port 12 a formed in the upper mold 12. For the molten resin m, for example, a thermoplastic resin such as polypropylene or polyethylene is used. The molten resin m injected into the cavity 13 from the injection port 12a is gradually filled from the second cavity 13B into the first cavity 13A and the third cavity 13C. The molten resin m injected into the cavity 13 is gradually cooled and hardened from the outer surface side.

  After this material filling process, the process proceeds to the pressurizing process.

  As shown in FIG. 4, in the pressurizing step, pressurized fluid is pressed into the cavity 13 from the pressurizing port 34 of the first core 30 attached to the mold 10. First, the pressurized fluid flows through the first pressurized port 34a, and the floating core 50 fitted and held on the inner peripheral surface 34c of the second pressurized port 34b is pushed out into the molten resin m. Since the central portion of the molten resin m along the cavity 13 is in a relatively low viscosity state, the floating core 50 is pushed into the molten resin m along the cavity 13 by the pressurized fluid.

  As shown in FIG. 5, the floating core 50 extruded into the molten resin m is centered along the cavity 13 of the molten resin m having a relatively low viscosity by the pressurized fluid continuously pressed into the cavity 13. The part advances through the second cavity 13B from the first cavity 13A side toward the third cavity 13C side. The floating core 50 forms the reference hollow inner peripheral surface in the molten resin m while pressing the molten resin m on the front side in the traveling direction against the cavity surface side of the cavity 13. At this time, the floating core 50 smoothly molds the irregularities on the reference hollow inner peripheral surface. At that time, excess molten resin m is sequentially pushed out from the discharge port 44 of the second core 40. The extruded molten resin m is discharged from the discharge port 44 to the molten resin tray.

  As shown in FIG. 6, when the floating core 50 reaches the third cavity 13 </ b> C, the excess molten resin m enters the discharge port 44 while pushing the excess molten resin m from the discharge port 44 of the second core 40 to the molten resin tray. Then, as shown in FIG. 7, the floating core 50 is discharged from the discharge port 44 into the molten resin tray by the pressure of the pressurized fluid. Thereby, the reference | standard hollow inner peripheral surface is shape | molded in the molten resin m, and the resin molded product M is shape | molded.

  After the pressurizing step, a long pipe product 60 in which the resin molded product M in the cavity 13 is cured is formed through a pressure holding step and a cooling step. After the long pipe product 60 is formed, the process proceeds to a mold opening process. In the mold opening process, the upper mold 12 is moved with respect to the lower mold 11 in the mold opening direction, and the long pipe product 60 is taken out.

  FIG. 8 is a diagram for explaining the outline of the long pipe product 60 manufactured by the method for manufacturing a tubular hollow molded product according to the present embodiment. As shown in the figure, the long pipe product 60 includes a thin pipe main body portion 62 corresponding to an intermediate portion and a first large diameter portion 61 and a second large diameter portion 63 formed by expanding the diameter relative to the pipe main body portion 62. Is formed at both ends of the pipe body 62. The inner diameters of the hollow inner peripheral surfaces 64 of the first large diameter portion 61 and the second large diameter portion 63 are formed to be larger than the inner diameter of the reference hollow inner peripheral surface of the pipe main body portion 62.

  According to the method for manufacturing a tubular hollow molded article having the above-described configuration, the first large-diameter portion 61 and the second large-diameter portion 63 that are expanded with respect to the pipe main body portion 62 are provided at both ends of the pipe main body portion 62. Then, the long pipe product 60 in which the inner diameter of the hollow inner peripheral surface 64 in the first large diameter portion 61 and the second large diameter portion 63 and the inner diameter of the reference hollow inner peripheral surface in the pipe main body portion 62 are different from each other is obtained. 30 and the second core 40 can be mounted on the mold 10, and the floating core 50 can be manufactured from the mounted first core 30 into the molten resin m along the cavity 13 with a simple configuration.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. In the above embodiment, the case where the first large-diameter portion 61 and the second large-diameter portion 63 are formed at both end portions of the long pipe product 60 has been described. For example, as shown in FIG. The present invention can also be applied to the case where the long pipe products 70 and 80 in which the large-diameter portions 71 and 81 are formed are formed. On the other hand, after the long pipe product 60 is molded, the long pipe product 60 may be cut at a desired portion of the pipe main body 62 to obtain the long pipe products 70 and 80.

DESCRIPTION OF SYMBOLS 10 Mold 11 Lower mold 12 Upper mold 13 Cavity 13A 1st cavity 13B 2nd cavity 13C 3rd cavity 13a 1st cavity surface 13b 2nd cavity surface 13c 3rd cavity surface 14a 1st core mounting surface 15a 2nd core Mounting surface 30 First core 32 Main body 34 Pressurization port 40 Second core 42 Main body 44 Discharge port 50 Floating cores 60, 70, 80 Long pipe product (tubular hollow molded product)
61 1st large diameter part 62 Pipe main body part 63 2nd large diameter part m Molten resin (resin material)

Claims (6)

A tubular hollow molded article having a large-diameter portion having a hollow inner peripheral surface whose diameter is larger than that of the reference hollow inner peripheral surface is formed at an end portion, and a cavity extending in an axial shape having both end portions opened to the outside is provided. In the method for producing a tubular hollow molded article using a mold,
The large-diameter portion in the cavity is spaced apart from the cavity surface for molding and protrudes into the cavity through a gap to mold the large-diameter portion between the cavity surface and the cavity and the outside of the mold. A mold clamping step in which a pressurizing port communicating with the pressurizing port is formed and a core having a floating core held on the cavity side of the pressurizing port is attached to one end of the cavity and the mold is clamped;
A material filling step of filling the cavity with a resin material;
The reference of the tubular hollow molded article is formed by pushing the floating core into the resin material by a pressurized fluid press-fitted from the pressure port after the resin material is filled in the cavity and moving along the cavity. A pressurizing step of forming a hollow inner peripheral surface and discharging the floating core from the other end of the cavity;
A method for producing a tubular hollow molded article, comprising: A shaft in which a tubular hollow molded product having a first large-diameter portion and a second large-diameter portion having a hollow inner peripheral surface expanded in diameter relative to a reference hollow inner peripheral surface is formed at both ends and both ends are opened to the outside. In a method for producing a tubular hollow molded article using a mold having a cavity extending in a shape,
The first large-diameter portion in the cavity is spaced apart from the cavity surface where the first large-diameter portion is molded and protrudes into the cavity through a gap to mold the first large-diameter portion between the cavity surface and the cavity and the molding A first core having a pressurization port communicating with the outside of the mold and having a floating core held on the cavity side of the pressurization port is attached to one end of the cavity, and the second large in the cavity The second large-diameter portion is formed between the cavity surface by projecting into the cavity through a gap apart from the cavity surface where the diameter portion is molded, and the cavity and the outside of the mold are communicated with each other. A mold clamping step in which a second core having a discharge port formed is attached to the other end of the cavity and the mold is clamped;
A material filling step of filling the cavity with a resin material;
The reference of the tubular hollow molded article is formed by pushing the floating core into the resin material by a pressurized fluid press-fitted from the pressure port after the resin material is filled in the cavity and moving along the cavity. Forming a hollow inner peripheral surface and discharging the floating core from the discharge port;
A method for producing a tubular hollow molded article, comprising: A resin material is filled in a cavity having both ends opened to the outside and extending in a shaft shape, and the floating core is pushed out by a pressurized fluid press-fitted into the resin material from the pressure port, along the cavity. The hollow inner peripheral surface is formed by forming the reference hollow inner peripheral surface of the tubular hollow molded article, discharging the floating core from the other end of the cavity, and expanding the diameter relative to the reference hollow inner peripheral surface. In a mold for forming a tubular hollow molded article having a large diameter portion at the end,
The large-diameter portion is attached to at least one end portion of the both ends of the cavity and protrudes into the cavity through a gap apart from a cavity surface that molds the large-diameter portion in the cavity. And a pressurizing port that communicates the cavity and the outside of the mold, and a core that holds a floating core on the cavity side of the pressurizing port. The core is
A base attached to the end of the cavity;
A body portion that is spaced apart from the cavity surface of the cavity in a state in which the base portion is attached to the cavity and protrudes into the cavity through a gap and that molds the large diameter portion with the cavity surface;
A pressure port penetrating along the axial direction of the main body from the base to the main body;
An inner peripheral surface that is formed on the main body side of the pressure port and that holds the floating core by fitting;
The mold according to claim 3, further comprising: A resin material is filled in a cavity having both ends opened to the outside and extending in a shaft shape, and the floating core is pushed out by a pressurized fluid press-fitted into the resin material from the pressure port, along the cavity. The first hollow inner peripheral surface of the tubular hollow molded article is molded, and the floating core is discharged from the discharge port to have a hollow inner peripheral surface whose diameter is expanded with respect to the reference hollow inner peripheral surface. In a mold for forming a tubular hollow molded article having a large diameter portion and a second large diameter portion at both ends,
The first large-diameter portion that is attached to one end of the cavity and is spaced apart from the cavity surface that molds the first large-diameter portion in the cavity and projects into the cavity through a gap. A first core that is formed with a pressure port that communicates the cavity and the outside of the mold, and holds a floating core on the cavity side of the pressure port;
The second large diameter is attached to the other end of the cavity and is spaced apart from the cavity surface for molding the second large diameter portion of the cavity and protrudes into the cavity through a gap. A second core formed with a discharge port for forming the portion and communicating the cavity and the outside of the mold;
A mold characterized by comprising. The first core is
A base attached to one end of the cavity;
A main body portion that is spaced from the cavity surface of the cavity with the base mounted in the cavity and protrudes into the cavity through a gap and that molds the first large diameter portion with the cavity surface; ,
A pressure port penetrating along the axial direction of the main body from the base to the main body;
An inner peripheral surface that is formed on the main body side of the pressure port and that holds the floating core by fitting,
The second core has a base attached to the other end of the cavity;
A main body that protrudes into the cavity through a gap while being spaced from the cavity surface of the cavity in a state in which the base is attached to the cavity, and that forms the second large-diameter portion with the cavity surface; ,
A discharge port penetrating with the same diameter as the floating core along the axial direction of the main body from the base to the main body.
The mold according to claim 5, wherein:

Images