JP2005262847A - Method for molding injection-molded product with hinge and injection mold assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method capable of simply molding a thin-walled hinge part hard to cause a crack by applying small pressure and capable of also adjusting the dimension in the thickness direction of the thin-walled hinge part. <P>SOLUTION: A mold assembly 9 comprising a plurality of mold parts 8 is closed and an inner core 2 is allowed to retreat not only to form part molding cavity parts 10 for molding a plurality of parts 6 but also to form a cavity part 3 for molding the thin-walled hinge part between the end edge parts of the adjacent part molding cavity parts. A hard resin 5 is injected in the part molding cavity parts 10 and the cavity part 3 for molding the thin-walled hinge part. Next, the inner core 2 is allowed to advance into the cavity part 3 for molding the thin-walled hinge part while a plurality of the mold parts are closed and the hard resin 5 in the cavity part 3 for molding the thin-walled hinge part is pressed to reduce the thickness of this part to mold the thin-walled hinge part 1 integrated with the adjacent parts 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of molding an injection molded product with hinges in which parts are integrated with a thin hinge part so as to be foldable, and an injection mold apparatus used for this molding method.

2. Description of the Related Art Conventionally, there is known a hinged injection molded product in which a part and a part are integrally molded by a thin hinge part so as to be bent. (For example, see Patent Document 1)
In the conventional example shown in Patent Document 1, a plurality of parts and a thin hinge part having a V-shaped cross section that integrally connects adjacent parts are integrally formed by the same hard resin. It is.

  However, conventionally, in order to integrally mold a plurality of components and a thin hinge portion having a V-shaped cross section that integrally connects adjacent components with the same hard resin, a mold including a plurality of mold portions is used. A part forming cavity for closing a mold device to form a plurality of parts, and a thin-walled hinge having both ends communicating with adjacent part forming cavities between end edges of adjacent part forming cavities Forming a thin hinge part forming cavity part with a short dimension in the thickness direction of the part forming cavity part for forming the part, and injecting a hard resin into the part forming cavity part and the thin hinge part forming cavity part Since a thin thin hinge part that is connected and integrated with adjacent parts is integrally molded, the hard resin injected from the gate to the part molding cavity is thick. Forcibly poured into the thin hinge part molding cavity, the internal stress remains in the thin hinge part molded in the thin hinge part molding cavity part, or welds are likely to appear in the thin hinge part part. For these reasons, in a hinged injection molded product molded by a conventional method, cracking occurs easily when the thin hinge part is bent repeatedly, and it cannot be used stably and repeatedly over a long period of time, and the product life is short. There's a problem.

  In addition, conventionally, the cavity is first formed with a dimension slightly larger than the thickness of the injection molded product to be molded, and in this state, the cavity is filled with a hard resin, and then the movable mold is formed. An injection molding method is known in which an injection molded product is molded by advancing a portion and thereby pressing a hard resin filled in a cavity over the entire surface.

Although it is conceivable to form an injection-molded article with a hinge by such an injection molding method, the hard mold filled in the cavity is pressed by advancing the movable mold part, so that the pressing area is large and large. There is a problem that it is necessary to apply pressure and the mold apparatus becomes large. In addition, there is a problem in that the dimension in the thickness direction of only the thin hinge portion cannot be freely adjusted even if an attempt is made to optimize the thickness depending on the type of hard resin material using the thickness of the thin hinge portion.
Japanese Patent Laid-Open No. 5-139441

  The present invention has been invented in view of the above-mentioned conventional problems, and can be easily formed by applying a small pressure to a thin hinge portion that does not easily crack and has a long life, and also uses a hard resin material. It is an object of the present invention to provide a method of molding an injection-molded product with a hinge and a mold apparatus for injection molding capable of adjusting the dimension in the thickness direction of the thin hinge portion so that the optimum dimension in the thickness direction can be obtained according to It is.

  In order to solve the above problems, the injection molding product with hinge according to the present invention has a mold device 9 composed of a plurality of mold parts 8 which is closed and movable in the mold part 8. The part molding cavity 10 for molding a plurality of parts 6 and the end part of the adjacent part molding cavity 10 communicate with the adjacent part molding cavity 10 between the end edges of the part molding cavity 10. The thin hinge part molding cavity part 3 is formed, the hard resin 5 is injected into the part molding cavity part 10 and the thin hinge part molding cavity part 3, and then a plurality of mold parts are kept closed. The inner core 2 is advanced into the thin hinge part molding cavity 3 to press the hard resin 5 in the thin hinge part molding cavity 3 to reduce the thickness of this part and integrate with the adjacent component 6. It is characterized in that for molding the hinge portion 1.

  By adopting such a method, when the hard resin 5 is injected into the component molding cavity 10 and the thin hinge molding cavity 3 communicating therewith, the thickness of the thin hinge molding cavity 3 is increased. Since the dimension in the direction is finally set to be larger than the thickness of the thin hinge portion 1 formed at this portion, the cavity portion 3 for forming the thin hinge portion from the cavity portion 10 for molding the component when the hard resin 5 is injected. The hard resin 5 smoothly flows and is filled, and the inner resin 2 compresses the hard resin 5 in the thin-walled hinge part molding cavity 3 so that no internal stress or weld is generated. The hinge part 1 can be easily formed by applying a small pressure, and the thickness of the thin hinge part 1 can be folded by adjusting the advance dimension of the inner core 2. In which it becomes possible to adjust so that the material in a suitable size of the hard resin 5 to be used on the bottom and strength.

  Further, a mold device 9 composed of a plurality of mold parts 8 is closed, and a first inner core 2 ′ provided movably on the mold part 8 is retracted and movably provided on the mold part 8. A part molding cavity 10 for molding the plurality of parts 6 by advancing the two inner cores 12 and a part of the edge in the longitudinal direction between the edge edges of the adjacent part molding cavities 10 Forming a thin-walled hinge part molding cavity 3 communicating with the part, and injecting a hard resin 5 into the part-molding cavity part 10 and the thin-walled hinge part molding cavity part 3 to form a plurality of parts 6 and adjacent parts 6 are connected to each other by the thin-walled hinge portion 1, and then the plurality of mold portions 8 are closed and the second inner core 12 is moved forward. Inner core 2 'with thin hinge The thin hinge part 1 which is advanced into the cavity part 3 and presses the hard resin 5 in the cavity part 3 for forming the thin hinge part to reduce the thickness of this part and is integrated with the adjacent part 6 is formed. In addition, the plurality of mold parts 8 are closed and the first inner core 2 ′ is moved forward, the second inner core 12 is moved backward, and the thin hinge part 1 in the longitudinal direction of the edge of the adjacent component 6 is moved. Forming a flexible hinge portion forming cavity portion 13 between the different portions, and injecting a soft resin 15 into the soft hinge portion forming cavity portion 13 in the longitudinal direction of the edge portion of the adjacent component 6. The molding method is characterized in that the soft hinge portion 11 is molded between the thin-walled hinge portion 1 and another portion that is displaced, and both ends of the soft hinge portion 11 are integrated with the ends of the adjacent components 6. May be.

  By adopting such a method, the hinge part for connecting the adjacent parts 6 so as to be foldable is formed in the thin hinge part 1 made of the same hard resin 5 as the part 6 in the longitudinal direction, and the soft hinge part made of the soft resin 15. 11 and can be integrally formed by injection molding with a hinge part that combines shape retention in the hinge part made of the thin hinge part 1 made of the hard resin 5 and repeated use in the soft hinge part 11, Moreover, the thin hinge portion 1 is formed in the thickness direction of the thin hinge portion molding cavity portion 3 when the hard resin 5 is injected into the component molding cavity portion 10 and the thin hinge portion molding cavity portion 3 communicating therewith. Since the dimension is finally set to be larger than the thickness of the thin hinge portion 1 formed at this portion, the component forming cavities at the time of injection of the hard resin 5 The hard resin 5 smoothly flows and is filled from the portion 10 into the thin hinge portion molding cavity portion 3, and then the inner resin 2 compresses the hard resin 5 in the thin hinge portion molding cavity portion 3, so that the internal stress is reduced. The thin hinge 1 that does not generate or weld can be easily formed by applying a small pressure, and in this respect, even if the thin hinge 1 is repeatedly used, no cracks can be generated. Further, by adjusting the advance dimension of the first inner core 2 ', the thickness of the thin hinge portion 1 is adjusted to a dimension suitable for the material of the hard resin 5 used in terms of bendability and strength. It is possible to adjust the thickness dimension of the soft hinge portion 11 by adjusting the retracted dimension of the first inner core 2.

  Further, the injection mold apparatus 9 of the present invention is a mold apparatus 9 for injecting a plurality of mold sections 8, an inner core 2 that can be moved forward and backward provided in the mold section 8, and a hard resin 5. And a gate molding part 10 for closing a plurality of mold parts 8 and retreating the inner core 2 to mold a plurality of parts 6, and an end of an adjacent part molding cavity part 10. A thin hinge part forming cavity part 3 is formed which is located between the edges and communicates with the adjacent part forming cavity part 10 at both ends, and is formed in the part forming cavity part 10 and the thin hinge part forming cavity part 3. The injection process of filling the hard resin 5, and then the inner core 2 is advanced into the thin hinge part forming cavity part 3 while the plurality of mold parts are closed, so that the inside of the thin hinge part forming cavity part 3 Press hard resin 5 It is characterized in that comprising providing a control unit for executing a thin hinge portion forming step of forming the part 6 and the thin hinge portion 1 made of the same material to the thin hinge portion molding cavity 3 Te.

  By setting it as such a structure, the metal mold | die apparatus 9 used for the injection molding method of Claim 1 which has the above-mentioned characteristic can be provided.

  Further, the injection mold apparatus of the present invention includes a plurality of mold parts 8 provided by the mold apparatus 9, a first inner core 2 ′ which can be moved forward and backward, and a second inner core 12 which can be moved forward and backward. And a first gate 4 ′ for injecting the hard resin 5 and a second gate 14 for injecting the soft resin 15, and closing the plurality of mold parts and the first inner core 2 ′. And the second inner core 12 is advanced to form a plurality of parts 6 and the longitudinal direction of the edge between the edge parts of the adjacent part forming cavities 10. Forming a thin hinge portion forming cavity portion 3 that communicates with a part of each other, filling the component forming cavity portion 10 and the thin hinge portion forming cavity portion 3 with a hard resin 5 to form a plurality of components 6. And the length of the edge of the adjacent part 6 After the primary injection process in which a part of the direction is integrally connected by the thin hinge part 1 and the primary injection process, the plurality of mold parts 8 are closed and the second inner core 12 is advanced, One inner core 2 'is advanced into the thin hinge part molding cavity part 3 and the hard resin 5 in the thin hinge part molding cavity part 3 is pressed to reduce the thickness of this part to form the thin hinge part 1. After the thin hinge part forming step and the thin hinge part forming step, the plurality of mold parts 8 are closed, the first inner core 2 ′ is advanced, and the first inner core 2 ′ is advanced, A core back step of retracting the second inner core 12 to form a cavity portion 13 for forming a soft hinge portion over another portion shifted from the thin hinge portion 1 in the longitudinal direction of an edge portion of an adjacent part 6; Soft hinge component The cavity portion 13 is filled with the soft resin 15, and the soft hinge portion 11 is molded between the thin hinge portion 1 in the longitudinal direction of the end portion of the adjacent component 6 and the other portion shifted from the thin hinge portion 1. 11 may be provided with a control unit that performs a secondary injection process in which both end portions of 11 are integrated with the end portions of the adjacent component 6.

  By setting it as such a structure, the metal mold | die apparatus 9 used for the injection molding method of Claim 2 which has an above-described characteristic can be provided.

  In the assembly box made of synthetic resin, when injecting hard resin, the dimension in the thickness direction of the thin hinge part molding cavity is set to be larger than the thickness of the thin hinge part finally formed in this part. When the hard resin is injected, the hard resin smoothly flows and fills from the part molding cavity to the thin hinge molding cavity, and then the hard resin in the thin hinge molding cavity is compressed by the inner core. Since the thin-walled hinge part is formed, the thin-walled hinge part that does not generate internal stress or welds can be easily molded by applying a small pressure, and the inner core's advancement dimension can be adjusted. Therefore, it becomes possible to adjust the thickness of the thin hinge portion so as to have a dimension suitable for the material of the hard resin used in terms of bendability and strength.

  Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings.

  FIG. 4 shows an example of a hinged injection molded product 7 molded according to the present invention. In FIG. 4, components 6 made of hard resin 5 are connected and integrated by a thin hinge portion 1 made of the same hard resin 5 so as to be foldable, and the whole is integrally formed by injection molding.

  FIGS. 1 to 4 show the molding sequence of the molding method for molding the hinged injection molded product 7.

  As shown in FIG. 1, an injection mold apparatus 9 (hereinafter referred to as a mold apparatus 9) for molding the hinged injection-molded product 7 is provided in a plurality of mold sections 8 and the mold section 8. An inner core 2 that can freely move forward and backward and a first gate 4 ′ for injecting hard resin 5 are provided. Here, as the hard resin 5 used, for example, PP (polypropylene), PE (polyethylene), HDPE (high density polyethylene), PC (polycarbonate), PVC (vinyl chloride resin), ABS resin and the like are used.

  The mold part 8 includes a fixed mold part 8a and a movable mold part 8b. The parts for closing the plurality of mold parts 8 and forming the plurality of parts 6 with the inner core 2 retracted. A thin-walled hinge molding cavity 3 is formed which is located between the molding cavity 10 and the edge molding between adjacent component molding cavities 10 and whose both ends communicate with the adjacent component molding cavity 10. Here, the thin hinge part molding cavity part 3 is formed between the tip surface of the inner core 2 and the mold part 8 (the fixed mold part 8a in the embodiment shown in the figure) facing the inner core 2; In the embodiment of the accompanying drawings, a triangular protrusion 21 having a triangular cross section is formed on the mold part 8 facing the tip surface of the inner core 2. In the state where the inner core 2 is retracted, the thin-walled hinge portion forming cavity portion 3 has a dimension between the front end surface of the inner core 2 and the front end portion of the triangular protrusion 21 provided on the mold portion 8 facing the inner core 2 (that is, The dimension of the portion having the shortest dimension in the thickness direction of the thin hinge portion forming cavity portion 3) is longer than the dimension of the thinnest portion of the thin hinge portion 1 to be finally formed, preferably the component forming cavity. The dimension of the portion 10 is approximately the same as the dimension in the thickness direction, and when the hard resin 5 is injected, the thin hinge hinge molding cavity 3 flows smoothly and is filled.

  In the embodiment shown in the accompanying drawings, a gate 4 for injecting the hard resin 5 into the component molding cavity 10 is provided in the fixed mold 8a.

  When the hinged injection molded article 7 is molded using the mold apparatus 9 as described above, it is performed as follows.

  First, as shown in FIG. 1, a mold device 9 including a plurality of mold parts 8 is closed and a plurality of parts for molding a plurality of parts 6 by retracting an inner core 2 provided movably on the mold part 8. Mold-closing step of forming the thin-walled hinge part forming cavity part 3 communicating with the parts in the longitudinal direction of the edge part between the edge parts of the part forming cavity part 10 and the adjacent part forming cavity part 10 Execute.

  Next, as shown in FIG. 2, an injection process of filling the hard resin 5 from the gate 4 to the part molding cavity 10 and the thin hinge molding cavity 3 is executed.

  Next, as shown in FIG. 3, the inner core 2 is advanced into the thin-wall hinge molding cavity 3 with the plurality of mold parts closed, and the hard resin 5 in the thin-wall hinge molding cavity 3 is moved. The thin hinge part molding step of molding the thin hinge part 1 made of the same material as the component 6 in the thin hinge part molding cavity part 3 by pressing to reduce the thickness direction dimension of the thin hinge part molding cavity part 3 Execute.

  In this way, a hinged injection molded product 7 in which a plurality of components 6 and adjacent components 6 are connected and integrated by the thin hinge portion 1 made of the same hard resin 5 is formed using the same mold device 9.

  Next, the mold apparatus 9 is opened, and a mold release process is performed in which an injection molded product 7 with a hinge in which adjacent parts 6 are connected and integrated by the thin hinge 1 is taken out, and the hinge as shown in FIG. The attached injection molded product 7 is obtained.

  The series of mold closing process, injection process, thin hinge part forming process, and mold releasing process are executed under the control of a control unit (not shown).

  According to the above molding method, the inner core 2 is retracted during the injection process so that the thickness direction dimension of the thin hinge part molding cavity part 3 is finally made larger than the thickness of the thin hinge part 1 to be molded. In the injection process, the hard resin 5 smoothly flows and fills the cavity portion 3 for molding the thin hinge portion, and internal stress is applied to the thin hinge portion 1 as in the case of forming the conventional thin hinge portion 1. It does not occur or welds occur. In addition, since only the hard resin 5 in the thin hinge part molding cavity 3 is compressed by the inner core 2, it is easy to apply a small pressure to the thin hinge part 1 where no internal stress or weld occurs. It can be molded. In addition, by adjusting the forward dimension of the inner core 2, the thickness of the thin hinge portion 1 can be adjusted to a dimension suitable for the material of the hard resin 5 used in terms of bendability and strength. As a result, the thin hinge portion 1 molded by the molding method of the present invention is harder to break than conventional ones even if it is repeatedly bent, can be used repeatedly, has a long life, and can be used stably for a long time. It is.

  Next, another embodiment of the present invention will be described with reference to FIGS.

  In the present embodiment, a hinged injection molded product 7 as shown in FIG. 10 is formed. An injection molded product 7 with a hinge shown in FIG. 10 has a thin hinge portion 1 in which adjacent parts 6 molded from a hard resin 5 are made of the same hard resin 5 as the part 6 in a part in the longitudinal direction of the edge of the part 6. And the adjacent parts 6 are connected and integrated by the soft hinge portion 11 at other parts in the longitudinal direction of the parts 6.

  10 is molded in the order of FIG. 5 → FIG. 6 → FIG. 7 → FIG. 8 → FIG. 9 using a mold apparatus 9 as shown in FIG. Yes. 5 (a), FIG. 6 (a), FIG. 7 (a), FIG. 8 (a), and FIG. 9 (a) show the XX portion of FIG. 10 (a) of the mold apparatus 9 in each step. FIG. 5 (b), FIG. 6 (b), FIG. 7 (b), FIG. 8 (b), and FIG. 9 (b) are mold apparatuses in each process, respectively. 9 is a cross-sectional view of a portion corresponding to a portion for forming the YY portion of FIG.

  As shown in FIGS. 5 (a) and 5 (b), an injection mold apparatus 9 (hereinafter referred to as mold apparatus 9) for molding the hinged injection molded article 7 shown in FIG. 8, a first inner core 2 ′, a second inner core 12, a first gate 4 ′ for injecting a hard resin 5, and a soft resin 15 are injected. And a second gate 14 for the purpose. Here, as the hard resin 5 used, for example, PP (polypropylene), PE (polyethylene), HDPE (high density polyethylene), PC (polycarbonate), PVC (vinyl chloride resin), ABS, as in the above-described embodiment. Resin or the like is used. Moreover, as the soft resin 15 used, TPE (elastomer), LDPE (low density polyethylene), EVA (ethylene vinyl acetate copolymer) etc. are used, for example.

  The mold part 8 includes a fixed mold part 8a and a movable mold part 8b. The plurality of mold parts 8 are closed, the second inner core 12 is advanced, and the first inner core 2 'is retracted. Cavity part 10 for molding a part for molding a plurality of parts 6 and a cavity for molding a thin-walled hinge part communicating with a part of the longitudinal direction of the edge part between the edge parts of adjacent part molding cavity parts 10 Part 3 is formed. Here, the thin hinge part molding cavity part 3 is formed between the tip surface of the inner core 2 and the mold part 8 (the fixed mold part 8a in the embodiment shown in the figure) facing the inner core 2; In this embodiment, a triangular protrusion 21 having a triangular cross section is formed on the mold portion 8 facing the tip surface of the inner core 2. In the state where the inner core 2 is retracted, the thin-walled hinge portion forming cavity portion 3 has a dimension between the front end surface of the inner core 2 and the front end portion of the triangular protrusion 21 provided on the mold portion 8 facing the inner core 2 (that is, The dimension of the portion having the shortest dimension in the thickness direction of the thin hinge portion forming cavity portion 3) is longer than the dimension of the thinnest portion of the thin hinge portion 1 to be finally formed, preferably the component forming cavity. The dimension of the portion 10 is approximately the same as the dimension in the thickness direction, and when the hard resin 5 is injected, the thin hinge hinge molding cavity 3 flows smoothly and is filled.

  Further, when the plurality of mold parts 8 are closed and the second inner core 12 is retracted, the first inner core 2 ′ is advanced so as to shorten the thickness direction dimension of the thin hinge part forming cavity part 3. For forming a flexible hinge portion communicating with the adjacent component forming cavity portion 10 at a position different from the thin hinge portion forming cavity portion 3 in the longitudinal direction of the end edge portion between the end edge portions of the adjacent component forming cavity portions 10. A cavity portion 13 is formed.

  In the embodiment shown in the accompanying drawings, the first mold 4a for injecting the hard resin 5 into the component molding cavity 10 is provided in the fixed mold 8a, and the first mold 4a of the fixed mold 8a is provided. A second gate 14 is provided at a portion facing the second inner core 12.

  When the hinged injection molded article 7 is molded using the mold apparatus 9 as described above, it is performed as follows.

  First, as shown in FIGS. 5 (a) and 5 (b), the mold device 9 including a plurality of mold portions 8 is closed, and the second inner core 12 is advanced as shown in FIG. 5 (b). As shown in a), the first inner core 2 ′ is moved backward to mold a plurality of components 6, and between the end edges of the adjacent component molding cavities 10, A mold closing process for forming the thin hinge part forming cavity part 3 communicating with parts in the longitudinal direction is performed.

  Next, as shown in FIGS. 6 (a) and 6 (b), a primary injection process for filling the resin molding cavity 10 and the thin hinge molding cavity 3 with the hard resin 5 from the first gate 4'a is performed. To do.

  Next, the plurality of mold parts 8 are closed as shown in FIGS. 7A and 7B, and the first inner core 2 ′ is moved while the second inner core 12 is advanced as shown in FIG. 7B. Is moved forward into the thin hinge part molding cavity 3 to press the hard resin 5 in the thin hinge part molding cavity 3 to reduce the thickness of the thin hinge part molding cavity 3 in the thickness direction. A thin hinge portion molding step is performed in which the thin hinge portion 1 made of the same material as that of the component 6 is formed in the hinge portion forming cavity portion 3.

  Next, the plurality of mold parts are closed as shown in FIGS. 8A and 8B, and the first inner core 2 ′ is advanced as shown in FIG. As described above, the second inner core 12 is moved backward to form the flexible hinge portion molding cavity portion 13 extending between the thin hinge portion 1 in the longitudinal direction of the edge portion of the adjacent component 6 and shifted from the other portion. Execute the process.

  Next, the soft resin 15 is injected from the second gate 14 into the cavity 13 for forming the soft hinge portion, and between the thin hinge portion 1 in the longitudinal direction of the end edge portion of the adjacent component 6 and other portions shifted from each other. A secondary injection process for forming the soft hinge portion 11 is performed.

  The hinged injection molded product 7 in which the plurality of components 6 and the adjacent components 6 are connected and integrated by the thin hinge portion 1 and the soft hinge portion 11 made of the same hard resin 5 uses the same mold device 9. Formed.

  Next, the mold apparatus 9 is opened, and a mold release process is performed in which an injection molded product 7 with a hinge in which adjacent parts 6 are connected and integrated by the thin hinge 1 is taken out, and the hinge as shown in FIG. The attached injection molded product 7 is obtained.

  The series of mold closing process, primary injection process, thin hinge part molding process, core back process, secondary injection process, and mold release process are executed under the control of a control unit (not shown).

  According to the molding method described above, the first inner core 2 is retracted during the primary injection step so that the dimension in the thickness direction of the thin hinge part molding cavity part 3 is finally molded more than the thickness of the thin hinge part 1. By increasing the size, the hard resin 5 smoothly flows and fills the thin hinge portion molding cavity 3 in the injection process, and the thin hinge portion 1 portion is formed as in the case of forming the conventional thin hinge portion 1. The thin-walled hinge portion 1 that does not generate internal stress or weld can be easily formed by applying a small pressure, and by adjusting the advance dimension of the inner core 2, the thin-walled hinge portion 1 It is possible to adjust the thickness of the material so as to have a dimension suitable for the material of the hard resin 5 used in terms of bendability and strength. Therefore, the thin hinge portion 1 is harder to break than conventional ones even if it is repeatedly bent, and can be used repeatedly, has a long life, and can be used stably for a long time. Moreover, it is composed of the hard resin 5 by comprising the thin hinge portion 1 made of the same hard resin 5 and the soft hinge portion 11 made of the soft resin 15 as the components 6 that connect the components 6 made of the adjacent hard resin 5 together. It has both shape retention at the hinge portion made of the thin-walled hinge portion 1 and repeated usability at the soft hinge portion 11, further extending the life and allowing stable use for a long time. Here, when the cavity portion 13 for forming the soft hinge portion is formed, it is adjacent to the thin-walled hinge portion 1 filled in the thin-walled hinge portion forming cavity portion 3 in the longitudinal direction along the edge of the component 6. When formed, the soft hinge portion 11 and the thin hinge portion 1 can be connected and integrated in the longitudinal direction, whereby the thin hinge portion 1 can be prevented from cracking from the end by the soft hinge portion 11.

  FIG. 4 and FIG. 10 show an example of a simplified configuration as a hinged injection molded product 7, and the injection molding method of the hinged injection molded product 7 with this configuration simplified is shown in FIGS. 1 to 3, 5 to 5. As described with reference to the mold apparatus shown in FIG. 9, as the hinged injection molded product 7, all or a part of the hinge part is connected by the thin hinge part 1 so that the parts 6 can be bent together. Various other hinged products may be used. For example, a face plate that is a component 6 as shown in FIGS. 11 and 15 can be bent with all or a part of the hinge portion being a thin hinge portion 1. An assembly box connected to can be given as a specific example.

  FIGS. 11 (a) and 15 (a) show a state in which an assembly box, which is an injection molded product 7 with hinges, is unfolded in a planar shape, and the same as FIGS. 11 (b) and 15 (b). The state which assembled the assembly box which is the injection-molded product 7 with a hinge in box shape is shown. In addition, in the case where the adjacent face plates which are the parts 6 are adjacent to each other at right angles in parts other than the hinge part when assembled in a box shape, the parts 6 are connected to each other by any conventionally known connecting means in this type of assembly box. Link. In the embodiment shown in the accompanying drawings, an assembly box is configured by a square or rectangular bottom plate as the component 6 and four side plates integrally connected to the four sides of the bottom plate via hinges. For example, the same unfolded form of this type of assembly box in a corrugated cardboard is used as the unfolded form, such as a cover plate integrally connected to one or more side plates via hinges. Of course you can.

  FIG. 12 to FIG. 14 show the respective steps of the mold apparatus 9 portion corresponding to the XX line portion of FIG. That is, FIG. 12 shows a mold closing process, FIG. 13 shows an injection process, and FIG. 14 shows a thin hinge part forming process.

  12, 13, and 14 correspond to the processes in FIGS. 1, 2, and 3, respectively, and control is performed in the same manner as described in the processes in FIGS. 1, 2, and 3. Each process is executed by the unit, and the illustration is omitted at the end. Similarly, the mold release process is executed by control to take out the assembly box as shown in FIG. is there. The assembly box which is the injection molded product 7 with hinge molded according to the present embodiment can be reused repeatedly without cracking even if the thin hinge portion 1 is repeatedly bent.

  16A, FIG. 17A, FIG. 18A, FIG. 19A, and FIG. 20A are molds corresponding to the XX line portion of FIG. 15A, respectively. FIG. 16B, FIG. 17B, FIG. 18B, FIG. 19B, and FIG. 20B show Y in FIG. 15A, respectively. Each process of the mold apparatus 9 part corresponding to the -Y line part is shown. 16 shows a mold closing process, FIG. 17 shows a primary injection process, FIG. 18 shows a thin hinge part forming process, FIG. 19 shows a core back process, and FIG. 20 shows a secondary injection process. 18, 19, and 20 are executed by the control unit in the same manner as described in the above-described steps of FIGS. 5, 6, 7, 8, and 9. However, similarly, the mold release step is executed by control to take out the assembly box as shown in FIG.

  The assembly box which is the hinged injection-molded product 7 as shown in FIG. 15 formed in the order shown in FIGS. 16 to 20 has the same function and effect as the embodiment shown in FIG.

  Here, as shown in FIG. 21, when the outer surface of the soft hinge portion 11 made of the soft resin 15 is configured to protrude outward from the outer surface of the component 6, the soft hinge portion 11 not only has a hinge function but also slips. It exerts a stop function to prevent the assembly box from slipping and slipping, and further absorbs shocks.

It is sectional drawing of the mold closing state of the mold apparatus for injection molding used for the molding method of the injection molded product with a hinge of this invention. It is sectional drawing of an injection molding process same as the above. It is sectional drawing of a thin hinge part shaping | molding process same as the above. An example of the injection molding product with a hinge shape | molded by the same as the above is shown, (a) is a perspective view, (b) is sectional drawing. The mold closing process of other embodiment of the injection mold apparatus of other embodiment of this invention is shown, (a) is the injection mold corresponding to the XX line part of Fig.10 (a). It is sectional drawing of an apparatus, (b) is sectional drawing of the die apparatus for injection molding corresponding to the YY line part of Fig.10 (a). The primary injection molding process same as the above is shown, (a) is a cross-sectional view of an injection molding die device corresponding to the XX line portion of FIG. 10 (a), (b) is a cross-sectional view of FIG. 10 (a). It is sectional drawing of the mold apparatus for injection molding corresponding to a YY line part. The thin hinge part shaping | molding process same as the above is shown, (a) is sectional drawing of the injection molding die apparatus corresponding to the XX line part of Fig.10 (a), (b) is FIG.10 (a). It is sectional drawing of the metal mold | die apparatus for injection molding corresponding to the YY line part. The core back process same as the above is shown, (a) is a cross-sectional view of an injection molding die apparatus corresponding to the XX line part of FIG. 10 (a), (b) is Y in FIG. 10 (a). It is sectional drawing of the mold apparatus for injection molding corresponding to the -Y line part. The secondary injection process same as the above is shown, (a) is a cross-sectional view of an injection mold apparatus corresponding to the XX line part of FIG. 10 (a), (b) is a cross-sectional view of FIG. 10 (a). It is sectional drawing of the mold apparatus for injection molding corresponding to a YY line part. An example of the injection molded product with hinges molded by the same as above is shown, (a) is a perspective view, (b) and (c) are sectional views taken along lines XX and YY of (a), respectively. is there. An example of an assembly box as a specific example of a hinged injection molded product molded by the molding method of the present invention is shown, (a) is a developed view, (b) is a perspective view assembled in a box shape, (C) is a perspective view of the A part of (a). These are sectional drawings of the mold closing state of the mold apparatus for injection molding corresponding to the XX line part of Drawing 11 (a) same as the above. It is sectional drawing of the injection molding process in the injection die apparatus corresponding to the XX line part of Fig.11 (a) same as the above. It is sectional drawing which shows the thin hinge part shaping | molding process in the injection die apparatus corresponding to the XX line part of Fig.11 (a) same as the above. The other example of the assembly box as a specific example of the injection molding product with a hinge shape | molded by the shaping | molding method of this invention is shown, (a) is an expanded view, (b) was assembled in the box shape. It is a perspective view, (c), (d) is sectional drawing of XX line of (a), respectively, and YY line, (e), (f) is the surface of A part of (a), respectively It is the perspective view seen from the side and the back surface side. The mold closing process in the shaping | molding method which shape | molds an assembly box same as the above is shown, (a) is sectional drawing of the injection die apparatus corresponding to the XX line part of Fig.15 (a), (b) FIG. 16 is a cross-sectional view of an injection mold apparatus corresponding to the YY line portion of FIG. The primary injection molding process same as the above is shown, (a) is a cross-sectional view of an injection mold apparatus corresponding to the XX line part of FIG. 15 (a), (b) is Y of FIG. 15 (a). It is sectional drawing of the mold apparatus for injection molding corresponding to the -Y line part. The thin hinge part shaping | molding process same as the above is shown, (a) is sectional drawing of the die apparatus for injection molding corresponding to the XX line part of Fig.15 (a), (b) is FIG.15 (a). It is sectional drawing of the mold apparatus for injection molding corresponding to a YY line part. The core back process same as the above is shown, (a) is a cross-sectional view of the mold apparatus for injection molding corresponding to the XX line part of FIG. 15 (a), (b) is Y-- of FIG. 15 (a). It is sectional drawing of the die apparatus for injection molding corresponding to a Y line part. The secondary injection process same as the above is shown, (a) is a cross-sectional view of the mold apparatus for injection molding corresponding to the XX line part of FIG. 15 (a), (b) is Y in FIG. 15 (a). It is sectional drawing of the mold apparatus for injection molding corresponding to the -Y line part. It is sectional drawing of other embodiment of the injection molding goods with a hinge same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thin-walled hinge part 2 Inner core 2 '1st inner core 3 Cavity part for thin-walled hinge part shaping | molding 4 Gate 4' 1st gate 5 Hard resin 6 Parts 7 Injection molding product with hinges 8 Mold part 9 Mold apparatus 10 Parts molding Cavity part 11 Soft hinge part 12 Second inner core 13 Cavity part for soft hinge part molding 14 Second gate 15 Soft resin

Claims (4)

  Closes the mold device consisting of a plurality of mold parts and retracts the inner core provided movably on the mold part to mold the parts, and molds adjacent parts. Forming a thin-walled hinge part molding cavity part communicating with the adjacent part molding cavity part between the edge parts of the cavity part for molding, and forming a hard resin in the part molding cavity part and the thin-walled hinge part molding cavity part Next, with the plurality of mold parts closed, the inner core is advanced into the thin hinge molding cavity and the hard resin in the thin hinge molding cavity is pressed to increase the thickness of this part. Forming a thin hinge portion integrated with an adjacent part by thinning the mold, and forming a hinged injection molded product.   The mold device comprising a plurality of mold parts is closed, the first inner core provided movably on the mold part is retracted, and the second inner core provided movably on the mold part is advanced. In addition, a cavity part for molding a part for molding a plurality of parts and a cavity part for molding a thin hinge part that communicates with a part of the longitudinal direction of the edge part between the edge parts of adjacent part molding cavity parts Forming a plurality of parts by injecting a hard resin into the part forming cavity part and the thin hinge part forming cavity part, and forming a thin hinge part between adjacent parts in the longitudinal direction. Next, the plurality of mold parts are closed, and the first inner core is advanced into the thin hinge part forming cavity part while the second inner core is advanced, and the thin hinge part is formed. For mold Press the hard resin in the inner part to reduce the thickness of this part and form a thin hinge part integrated with the adjacent parts, then close the mold parts and advance the first inner core The second inner core is moved backward while being left to form a cavity portion for forming a soft hinge portion extending over the other portion of the edge portion of the adjacent part that is displaced from the thin hinge portion in the longitudinal direction. A soft resin is injected into the cavity portion for molding, and the soft hinge portion is formed between the thin hinge portion in the longitudinal direction of the end edge portion of the adjacent part and the other portion shifted from the adjacent portion, and both ends of the soft hinge portion are adjacent to each other. A method for forming a hinged injection-molded product, characterized by being integrated with an end of a part to be manufactured. An injection mold apparatus for use in the method of molding a hinged injection molded article according to claim 1, wherein the mold apparatus includes a plurality of mold parts, and an inner core that can be moved forward and backward provided in the mold parts, A gate for injecting hard resin,
A mold molding cavity for molding a plurality of parts by closing a plurality of mold parts and retreating an inner core, and both end portions are positioned between edge parts of adjacent mold molding cavities. An injection step of forming a thin hinge portion molding cavity portion communicating with an adjacent component molding cavity portion, and filling the component molding cavity portion and the thin hinge portion molding cavity portion with a hard resin;
Next, with the plurality of mold parts closed, the inner core is advanced into the thin-wall hinge molding cavity and the hard resin in the thin-wall hinge molding cavity is pressed into the thin-wall hinge molding cavity. An injection mold apparatus comprising: a control unit that executes a thin hinge part forming step of forming a thin hinge part made of the same material as a part. 3. An injection mold apparatus for use in the method of molding a hinged injection molded article according to claim 2, wherein the mold apparatus includes a plurality of mold parts, and a first inner part that can be moved forward and backward. A core, a second inner core, a first gate for injecting hard resin, and a second gate for injecting soft resin,
A component molding cavity for molding a plurality of parts by closing a plurality of mold parts and retracting the first inner core and advancing the second inner core, and an adjacent part molding cavity Forming a thin-walled hinge part molding cavity that communicates with a part of the longitudinal direction of the edge part, and filling the part molding cavity part and the thin-walled hinge part molding cavity part with a hard resin. A primary injection step in which a plurality of parts are molded and a part in the longitudinal direction of the edge part of adjacent parts is integrally connected by a thin hinge part;
After the primary injection process, the plurality of mold parts are closed and the second inner core is advanced, and the first inner core is advanced into the thin hinge part forming cavity part to make the thin hinge part molding cavity. A thin hinge part molding step of pressing the hard resin in the part to reduce the thickness of this part and molding the thin hinge part;
After the thin hinge portion molding step, the plurality of mold portions are closed and the first inner core is advanced, the second inner core is retracted and the longitudinal direction of the edge of the adjacent part is A core back step of forming a cavity portion for forming a flexible hinge portion over another portion shifted from the thin hinge portion;
The soft hinge part is filled with a soft resin, and a soft hinge part is molded between the thin hinge part in the longitudinal direction of the end edge part of an adjacent part and the other part shifted from the thin hinge part. And a secondary injection step of integrating both end portions of the first and second end portions of adjacent parts with each other.

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