Molding device and molding method

Abstract

To provide molding equipment and molding methods that enable easy mold release from undercut areas and removal of molded products, even for molded products with complexly shaped undercut areas, which have been difficult to achieve with conventional molding equipment.SOLUTION: The molding equipment has a mold for forming an inner surface shape of a molded product and a mold release mechanism for releasing the mold from the molded product. The mold has a plurality of split cores arranged in an annular pattern to form an opening in the plan view from the mold opening direction of the mold, and the mold release mechanism moves the split cores simultaneously so that the opening shrinks to release the mold from the undercut portion and enable the mold to move in the mold opening direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a molding apparatus and a molding method for producing a molded product using a mold. [Background technology]

[0002] Conventionally, a molding apparatus for manufacturing a molded product using a mold has been known. The mold mainly has a first mold (cavity mold) having a recess for forming the outer surface (exterior surface) of the molded product, and a second mold (core mold) having a protrusion for forming the inner surface of the molded product. In a molding apparatus for injection molding, which is an example of a molding apparatus using a mold, molten resin is injected into a space formed when the first mold and the second mold are fitted together in a mold closed state, and is cooled and solidified. Then, the movable side of the first mold and the second mold (hereinafter referred to as the "movable mold") is moved in the mold opening direction to open the mold, and the molded product is taken out.

[0003] If a molded product has an undercut portion and the movable die cannot be moved in the mold opening direction when the molded product is removed from the metal mold, a process for releasing the movable die from the undercut portion (hereinafter referred to as "undercut process") is required. When manufacturing a molded product having an undercut portion on the inner surface, for example, a method is adopted in which the movable die is composed of a main die and a slide die (e.g., an inclined core), and the slide die is slid inward in conjunction with the mold opening operation of the main die, thereby releasing the slide die from the undercut portion (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 57-203512 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the molding device disclosed in Patent Document 1, different undercut processing structures are provided to gradually release the first and second blocks, which are slide molds, from the undercut parts of the molded product, and the structure of the molding device is complicated. In particular, when the undercut parts are provided continuously or discretely around the entire circumference of the inner surface of the molded product, applying the conventional undercut processing structures disclosed in Patent Document 1 etc. poses a space problem.

[0006] The object of the present invention is to provide a molding apparatus and a molding method that can easily release the mold from the undercut portion and remove the molded product, even if the molded product has an undercut portion with a complex shape that was difficult to achieve with conventional molding apparatuses. [Means for solving the problem]

[0007] The molding device according to the present invention comprises: A molding apparatus for manufacturing a molded product having an undercut portion on an inner surface, comprising: A mold for forming an inner shape of the molded product; a mold release mechanism for releasing the mold from the molded product; the mold has a plurality of divided cores arranged in an annular shape so as to form an opening in a plan view seen from a mold opening direction of the mold, The demolding mechanism simultaneously moves the split cores so that the openings are reduced. and translating each of the divided cores toward one of the two divided cores adjacent to the divided core, The mold is released from the undercut portion and made movable in the mold opening direction.

[0008] The molding method according to the present invention comprises the steps of: A molding method for producing a molded product having an undercut portion on an inner surface, comprising the steps of: a first step of forming the molded product using a die in which a plurality of divided cores are annularly arranged so that openings are formed on the inside; The split cores are simultaneously moved so that the opening is reduced. and translating each of the divided cores toward one of the two divided cores adjacent to the divided core, and a second step of releasing the mold from the undercut portion. Effect of the Invention

[0009] According to the present invention, even in the case of a molded product having an undercut portion with a complex shape that was difficult to achieve with conventional molding devices, the mold can be easily released from the undercut portion and the molded product can be removed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an external perspective view showing a molding device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the molding apparatus. [Diagram 3] 3A to 3C are diagrams showing a molded product produced by the molding device. [Figure 4] 4A and 4B are diagrams showing the core unit. [Diagram 5] 5A and 5B are diagrams showing the core unit before and after the undercut process. [Figure 6] 6A and 6B are diagrams showing the mold parts of the split core before and after the undercut process. [Figure 7] 7A and 7B are diagrams for explaining the moving direction of the split core. [Figure 8] 8A and 8B are diagrams showing another example of the core unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a diagram showing a molding apparatus 1 according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of the molding apparatus 1. Figs. 3A to 3C are diagrams showing a molded product 100 produced by the molding apparatus 1, with Fig. 3A being a perspective view, Fig. 3B being a plan view, and Fig. 3C being a cross-sectional view. Fig. 3B shows the internal structure of the molded product 100 (omitted except for inner surface shapes 131 to 136 and opening 111), and Fig. 3C shows a cross section taken along the line AA in Fig. 3B.

[0012] In the following description, the core unit 10 side of the molding apparatus 1 (the top plate 120 side of the molded product 100) is referred to as the "upper side," and the drive shaft 50 side of the molding apparatus 1 (the base 110 side of the molded product 100) is referred to as the "lower side." The mold opening direction D of the molding apparatus 1 coincides with the up-down direction.

[0013] As shown in FIGS. 3A to 3C, the molded product 100 is a component having a base 110, a top plate 120, and inner surface shapes 131-136. The base 110 has a circular opening 111 in the center. Although not shown, the peripheral edge of the opening 111 protrudes downward. The top plate 120 has a circular opening 121 in the center.

[0014] The inner surface shapes 131-136 have convex portions that are twisted and curved, and are disposed at equal intervals in the circumferential direction between the base 110 and the top plate 120. The inner end portions 131a-136a of the inner surface shapes 131-136 are located on the periphery of the opening 111 of the base 110, and are formed at an acute angle with respect to the base 110. Therefore, when the core unit 10, which is a movable mold, is moved downward, the inner end portions 131a-136a enter the lower side of the core unit 10 in the mold opening direction D, and become so-called undercut portions (hereinafter referred to as "undercut portions 131a-136a"). In this way, molded product 100 has undercut portions 131a-136a on the inner surface. Undercut portions 131a-136a are provided discretely in the circumferential direction on the peripheral edge of opening 111 of base 110, and therefore would be difficult to form using a conventional molding device (see, for example, Patent Document 1).

[0015] 1 and 2, the molding device 1 includes a core unit 10, a guide section 20, a guide holder 30, a rotating holder 40, and a drive shaft 50. In this embodiment, the guide section 20, the rotating holder 40, and the drive shaft 50 constitute a demolding mechanism RM that demolds the core unit 10 from the molded product 100 and moves it in the mold opening direction D when the molded product 100 is removed. Specifically, the split cores 11 to 16 are moved so that the opening 17 of the core unit 10 is reduced, whereby the core unit 10 is demolded from the undercut portions 131a to 136a of the molded product 100.

[0016] The core unit 10 is a metal mold that forms the undercut portions 131a-136a of the inner surface shapes 131-136 among the surface shapes of the molded product 100. Although not shown, the molding apparatus 1 is provided with a metal mold that forms shapes of the molded product 100 other than the undercut portions 131a-136a in addition to the core unit 10. The core unit 10 is a movable mold that is moved in a mold opening direction D when removing the molded article 100. By moving the core unit 10 downward, the mold is opened and the molded article 100 can be removed.

[0017] As shown in Figures 4A and 4B, the core unit 10 is composed of six split cores 11 to 16 of the same shape. Figure 4A shows the split cores 11 to 16 in an assembled state, and Figure 4B shows the split cores 11 to 16 in a state disassembled in a radial direction perpendicular to the mold opening direction D.

[0018] The split cores 11-16 have mold portions 11a-16a and guide block portions 11b-16b. The mold portions 11a-16a are portions that form the inner surface shapes 131-136 of the molded product 100. The guide block portions 11b-16b are portions that are supported by the guide portion 20.

[0019] Each of the mold parts 11a to 16a has a first side surface portion Sa1, a second side surface portion Sa2, and a third side surface portion Sa3. The first side surface portion Sa1 is a portion extending in the mold opening direction D and is formed flat. The second side surface portion Sa2 is a portion that abuts against the first side surface portion Sa2 of the adjacent mold parts 11a to 16a and is formed flat like the first side surface portion Sa1. In other words, adjacent split cores are in surface contact with each other and are constrained to each other. The third side surface portion Sa3 is a portion that forms the inner surface shapes 131-136 of the molded product 100. Before the undercut process for releasing the core unit 10 from the molded product 100 (for example, during molding), the third side surface portions Sa3 of adjacent mold parts 11a-16a are smoothly connected to each other without any gaps. The undercut portions 131a-136a of the molded product 100 are formed by recesses in the third side surface portion Sa3 that are connected to the second side surface portion Sa2.

[0020] The guide block portions 11b to 16b each have a first block surface Sb1 and a second block surface Sb2 extending in the mold opening direction D. The guide block portions 11b to 16b each have a pin insertion hole 11c to 16c that penetrates from the second block surface Sb2 in a predetermined direction. The extending direction of the pin insertion hole 11c to 16c coincides with the extending direction of the guide pins 21 to 26.

[0021] The split cores 11-16 are arranged in an annular shape so as to form an opening 17 in a plan view (hereinafter simply referred to as "plan view") seen from the mold opening direction D. Specifically, the opening 17 is formed by a non-contact portion of the first side surface portion Sa1 of the mold portions 11a-16a that does not contact the second side surface portion Sa2. In this embodiment, since the core unit 10 is composed of six split cores 11-16, the opening 17 has a regular hexagonal shape.

[0022] The opening 17 does not have to be a regular hexagon in the strict sense. For example, the first side surface portion Sa1 may have a flat contact portion that contacts the second side surface portion Sa2 before and after the undercut process, and the non-contact portion may have a partially curved shape. The contact portion between the first side surface portion Sa1 and the second side surface portion Sa2 may have a flat overall contact portion, and may have a recess or a notch formed locally. In such a case, the shape of the space defined by the plane including the portion where the first side surface portion Sa1 and the second side surface portion Sa2 contact each other in plan (here, a hexagon) may be treated as the shape of the opening 17.

[0023] The guide unit 20 has guide pins 21-26 and a core holder 27. The guide unit 20 moves the split cores 11-16 in a predetermined direction. The direction of movement of the split cores 11-16 is determined, for example, by using an angle θ with respect to the normal direction of a corresponding one of the sides of the regular hexagon of the opening 17.

[0024] The core holder 27 has a core accommodating portion 271 that accommodates the core unit 10. In a plan view, the core accommodating portion 271 has a star-shaped hexagonal shape that matches the plan view shape of the guide block portions 11b to 16b of the core unit 10. The inner surface of the core accommodating portion 271 abuts against the first block surface Sb1 and the second block surface Sb2 of the split cores 11 to 16 in a state before the undercut process (see FIG. 5A).

[0025] The guide pins 21-26 are fixed to the core holder 27 and inserted into the pin insertion holes 11c-16c of the split cores 11-16, respectively, to support the split cores 11-16 so as to be movable in a predetermined direction. The extending direction of the guide pins 21-26 is parallel to the guide surface 271a (see FIG. 5A, etc.) of the core accommodating portion 271 of the core holder 27 in a plan view. In this embodiment, the guide pins 21-26 are arranged at an incline with respect to a plane perpendicular to the mold opening direction D, so that the split cores 11-16 are moved inward in a plan view and at the same time moved downward. This makes it possible to prevent interference between the split cores 11-16 and the bulging portion 122 of the molded product 100 during the undercut process.

[0026] The guide holder 30 is fixed to the lower end of the core holder 27 and supports the core holder 27. The rotating holder 40 and the upper part of the drive shaft 50 are housed inside the guide holder 30. In addition, the guide holder 30 holds a mold (not shown) that forms the lower surface of the seat 110 of the molded product 100 by means of a flange portion provided on the lower part.

[0027] The rotary holder 40 is disposed below the core unit 10, and converts the motion of the drive shaft 50 in the mold opening direction D into circumferential rotational motion about the axis of the molding device 1 and transmits it to the split cores 11-16.

[0028] The drive shaft 50 has a core holding portion 51 and a shaft body 52. ​​The drive shaft 50 is connected to a drive source (not shown) and configured to be movable in a die opening direction D. The core holding portion 51 is inserted into the opening 17 of the core unit 10, and holds the assembled state of the core unit 10. In addition, the upper surface of the core holding portion 51 functions as a mold for forming the top plate 120 of the molded product 100. The shaft body 52 is provided with, for example, an engagement pin that engages with the rotating holder 40. Through the engagement pin, the linear motion of the shaft body 52 is converted into rotational motion and transmitted to the rotating holder 40. Note that a known technique can be applied to the mechanism for converting linear motion into rotational motion. As the drive shaft 50 moves overall in the mold opening direction D, the molding apparatus 1 transitions from a mold closed state to a mold open state.

[0029] Before the undercut process, the guide pins 21-26 are inserted into the respective split cores 11-16, and the core holding portion of the drive shaft 50 is inserted into the opening 17 of the core unit 10. As a result, the first block surface Sb1 and the second block surface Sb2 of the split cores 11-16 come into contact with the inner surface of the core accommodating portion 271 of the core holder 27, and the assembled state and posture of the core unit 10 are maintained (see FIG. 5A).

[0030] Molten resin is injected into a cavity of a mold including the core unit 10 before the undercut process, and a molded product 100 is formed (first step). The mold parts 11a-16a of the divided cores 11-16 form inner surface shapes 131-136 of the molded product 100. In particular, the undercut parts 131a-136a are formed by the parts of the third side surface parts Sa3 of the mold parts 11a-16a that are connected to the second side surface parts Sa2 (see FIG. 6A). In FIG. 6A, the parts of the mold parts 11a-16a that form the undercut parts 131a-136a are indicated by hatching.

[0031] Then, by simultaneously moving the split cores 11-16 so that the opening 17 is reduced, the core unit 10 is released from the undercut portions 131a-136a (second step). Specifically, during the undercut process, the drive shaft 50 moves in the mold opening direction D. When the core holding portion 51 of the drive shaft 50 comes out of the core unit 10, the split cores 11-16 become movable inward. When the drive shaft 50 moves further in the mold opening direction D, power is transmitted to the rotating holder 40 via the engagement pin, causing the rotating holder 40 to rotate in the circumferential direction R.

[0032] The split cores 11-16 move along the guide pins 21-26 in response to the rotational motion of the rotating holder 40 (see FIG. 5B). That is, each of the split cores 11-16 moves translationally toward one of the two split cores adjacent to it (here, the split core adjacent in the counterclockwise direction). At this time, the first block surface Sb1 of the split cores 11-16 slides along the guide surface 271a of the core holder 27, and the second block surface Sb2 moves away from the inner surface of the core accommodating portion 271 (see FIG. 5B). Since the split cores 11-16 are in contact with each other, they move translationally in a predetermined direction while maintaining their respective postures. That is, the split cores 11-16 receive power applied by the drive shaft 50 and the rotary holder 40 and move simultaneously by mutual motion transmission. As a result, the opening 17 narrows inward, and the third side surface portions Sa3 of the split cores 11-16 are released from the undercut portions 131a-136a (see FIG. 6B). This allows the core unit 10 to move in the mold opening direction D. The movable side of the molding device 1 is moved integrally in the mold opening direction D to remove the molded product 100.

[0033] 7A and 7B are views for explaining the movement directions M1 to M6 of the split cores 11 to 16. Figures 7A and 7B typically show a case where the first side surface portion Sa1 and the second side surface portion Sa2 of the split cores 11 to 16 are linear in plan view, and the inner surface of the molded product 100 is circular.

[0034] As shown in FIGS. 7A and 7B, the split cores 11 to 16 move in directions restricted by the guide portion 20, that is, along movement directions M1 to M6 that form an angle θ with respect to the normal directions N1 to N6 of the respective first side surface portions Sa1.

[0035] If the amount of displacement of each of the split cores 11-16 is L, then the split core 11 will be displaced by L·cosθ with respect to the normal direction N1 and by L·sinθ in the direction along the first side surface portion Sa1. The displacement of the split core 11 in the normal direction N1 affects the split core 12, while the displacement in the direction along the first side surface portion Sa1 does not affect the split core 12. Therefore, if the displacement of the split core 12 in the normal direction N1 is L·sinθ or more, the split cores 11 and 12 will not interfere with each other.

[0036] If the outer angle of the hexagon that is the planar shape of the opening 17 is A, the angle between the moving direction M2 of the split core 12 and the normal direction N1 of the split core 11 is expressed as (A-θ). Therefore, the displacement of the split core 12 in the normal direction N1 is expressed as L cos(A-θ).

[0037] Therefore, the condition for split cores 11 and 12 not to interfere with each other is L·cos(A-θ)≧L·sinθ. Since 0°<θ,(A-θ)<90° and the exterior angle A of a regular n-gon (n is the number of split cores) is given by 360° / n, the above condition is θ≧180° / n. Therefore, in the case of a regular hexagon, if θ≧30° (=180° / 6), split cores 11 and 12 can move without interfering with each other. This condition applies to all combinations of adjacent split cores 11 to 16.

[0038] In particular, when θ=30°, the split cores 11 and 12 have the same amount of displacement in the normal direction N1, so that the first side surface portion Sa1 of the split core 11 slides along the second side surface portion Sa2 of the split core 12. On the other hand, when θ>30°, the split cores 11 and 12 can move without interfering with each other, but a gap is formed between the first side surface portion Sa1 of the split core 11 and the second side surface portion Sa2 of the split core 12. Furthermore, if the angle θ is too large, interference between the third side portion Sa3 of the split core 11-16 and the inner surface shape 131-136 of the molded product 100 becomes more likely; however, since the interference can be avoided by the inner surface shape 131-136 of the molded product 100, the upper limit of the angle θ cannot be uniquely determined.

[0039] As described above, the molding apparatus 1 according to this embodiment is a molding apparatus for manufacturing a molded article 100 having undercut portions 131a-136a on its inner surface, and includes a core unit 10 (mold) that forms the inner surface shape 131-136 of the molded article 100, and a demolding mechanism RM that releases the core unit 10 from the molded article 100. The core unit 10 has a plurality of split cores 11-16 that are arranged in an annular shape so as to form an opening 17 in a plan view seen from the mold opening direction D. The demolding mechanism RM simultaneously moves the split cores 11-16 so as to reduce the opening 17, thereby enabling the core unit 10 to be released from the undercut portions 131a-136a and moved in the mold opening direction D.

[0040] Furthermore, the molding method according to the embodiment is a molding method for producing a molded product 100 having undercut portions 131a-136a on its inner surface, and includes a first step of forming the molded product 100 using a core unit 10 (mold) in which multiple split cores 11-16 are arranged in a ring shape so that an opening 17 is formed on the inside, and a second step of simultaneously moving the split cores 11-16 so that the opening 17 is reduced, and releasing the core unit 10 from the undercut portions 131a-136a.

[0041] According to the molding device 1 and molding method of the embodiment, the opening of the core unit 10 is reduced by the movement of the divided cores 11-16, so that even if the molded product 100 has undercut portions 131a-136a with a complex shape that was difficult to achieve with conventional molding devices, the core unit 10 can be easily released from the undercut portions 131a-136a and the molded product 100 can be removed. This increases the productivity of the molded product 100, making it suitable for mass production of the molded product 100.

[0042] In the molding apparatus 1, the demolding mechanism RM translates each of the divided cores 11-16 toward one of the two divided cores adjacent to that divided core 11-16. This allows the split cores 11 to 16 to move so that adjacent split cores do not interfere with each other, and as a result, the opening 17 can be narrowed while being contracted inward.

[0043] In the molding device 1, the demolding mechanism RM applies power to the split cores 11 to 16, and moves the split cores 11 to 16 simultaneously by transmitting motion between the split cores 11 to 16. This allows the structure of the demolding mechanism RM for simultaneously moving the divided cores 11 to 16 to be simplified.

[0044] In addition, in the molding device 1, the number of split cores 11-16 is six (n), the opening 17 is a regular hexagon (regular n-gon) when viewed in a plane, and the demolding mechanism RM has a guide section 20 that moves each of the split cores 11-16 in a direction that forms a predetermined angle θ with respect to the normal directions N1-N6 of the corresponding sides of the regular hexagon. This allows the split cores 11 to 16 to be reliably moved in the desired moving directions M1 to M6 while maintaining their posture, and allows the core unit 10 to be easily released from the undercut portions 131a to 136a.

[0045] In the molding device 1, the predetermined angle θ satisfies θ≧30° (θ≧180° / N). This makes it possible to prevent interference between the split cores 11 to 16, and ensures that the undercut process is carried out.

[0046] In the molding apparatus 1, the guide portion 20 has guide pins 21 to 26 that are inserted into the split cores 11 to 16, and the guide pins 21 to 26 are disposed at an angle with respect to a plane perpendicular to the mold opening direction D. This makes it possible to accommodate cases such as the molded product 100, which has a bulging portion 122 in the center and in which the split cores 11 to 16 cannot be moved within a plane.

[0047] In addition, in the molding apparatus 1, the demolding mechanism RM further includes a drive shaft 50 that moves the core unit 10 (mold) in the mold opening direction D, and a rotating holder 40 (power transmission unit) that converts the movement of the drive shaft 50 in the mold opening direction D into movement in the circumferential direction R about the axis of the molding apparatus 1 and transmits it to the split cores 11-16. As a result, the core unit 10 is released from the undercut portions 131a to 136a by utilizing the movement in the mold opening direction D for releasing the core unit 10 from the molded product 100, so that the device configuration can be simplified.

[0048] The invention made by the inventor has been specifically described above based on an embodiment, but the present invention is not limited to the above embodiment and can be modified within the scope of the gist of the invention.

[0049] For example, the demolding mechanism RM is not limited to the configuration shown in the embodiment, but may have a configuration that simultaneously moves the split cores 11-16 to reduce the opening 17. Furthermore, the demolding mechanism RM may have a configuration that independently moves each of the split cores 11-16, rather than a configuration that simultaneously moves the split cores 11-16 by transmitting motion between the split cores 11-16.

[0050] The divided cores 11-16 may have partially different configurations, such as the shape of the third side portion Sa3. The shape of the third side portion Sa3 is designed according to the shape of the inner surface of the molded product. For example, the present invention can also be applied to a molded product in which an undercut portion is provided continuously in the circumferential direction.

[0051] Furthermore, the number of split cores constituting the core unit 10 is not limited to six, and as long as there are four or more, they can be moved simultaneously without interfering with each other. In particular, when the number of split cores is 5 to 7, the split cores can be moved simultaneously smoothly without interfering with each other and released from the molded product P. As shown in FIG. 8A, when the number of split cores C is 5, the angle θ that defines the moving direction M of the split cores C is preferably θ=36° (=180° / 5). Furthermore, as shown in FIG. 8B, when the number of split cores C is 7, the angle θ that defines the moving direction M is preferably θ=25.71° (=180° / 7).

[0052] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0053] 1 Molding equipment 10 Core unit (mold) 11~16 split core 17 Aperture 20 Guide section 30 Guide Holder 40 Rotating holder (power transmission part) 50 Drive shaft 100 Molded products 131~136 Inner shape 131a~136a Undercut section D-type opening direction RM demolding mechanism

Claims

1. A molding apparatus for manufacturing a molded product having an undercut portion on an inner surface, comprising: A mold for forming an inner shape of the molded product; a mold release mechanism for releasing the mold from the molded product; the mold has a plurality of divided cores arranged in an annular shape so as to form an opening in a plan view seen from a mold opening direction of the mold, the mold release mechanism simultaneously moves the split cores so that the opening is reduced, and translates each of the split cores toward one of the two split cores adjacent to the split core, thereby releasing the die from the undercut portion and enabling it to move in the mold opening direction. Molding equipment.

2. The demolding mechanism applies power to the split cores and simultaneously moves the split cores by transmitting motion between the split cores. The molding apparatus of claim 1 .

3. The number of the divided cores is n, The opening has a regular n-sided polygon in the plan view, the demolding mechanism has a guide portion that moves each of the divided cores in a direction that forms a predetermined angle θ with respect to a normal direction of a corresponding one of the sides of the regular n-gon. The molding apparatus of claim 2.

4. The predetermined angle θ satisfies θ≧180° / N, The molding apparatus according to claim 3.

5. The guide portion has a guide pin that is inserted into the split core, The guide pin is disposed at an angle with respect to the plane in the plan view.

5. The molding apparatus according to claim 3 or 4.

6. The demolding mechanism includes: A drive shaft that moves the mold in the mold opening direction; and a power transmission unit that converts the motion of the drive shaft in the mold opening direction into a circumferential motion around the axis of the molding device and transmits the motion to the split core. A molding apparatus according to any one of claims 1 to 5.

7. A molding method for producing a molded product having an undercut portion on an inner surface, comprising the steps of: a first step of forming the molded product using a die in which a plurality of divided cores are annularly arranged so that openings are formed on the inside; a second step of simultaneously moving the split cores so that the openings are reduced, and translating each of the split cores toward one of the two split cores adjacent to the split core, thereby releasing the die from the undercut portion; The molding method comprising:

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