Mold device and injection molding method

Abstract

The mold device (100) includes a primary mold (26) formed by a cavity mold (16) and a primary core mold (10), and a secondary mold (28) formed by the cavity mold (16) and a secondary core mold (12). The cavity mold (16) includes a primary molded product holding portion (30) that can move in and out relative to the first cavity (C1) on the parting line (PL) of the primary mold (26). The secondary core mold (16) includes a sliding portion (40) having a shape complementary to the primary molded product holding portion (30) that can move in and out relative to the second cavity (C2) on the parting line of the secondary mold (28). When the primary mold is opened, the primary molded product holding portion (30) protruding into the first cavity (C1) holds the primary molded product (92) on the cavity mold (16) by engaging with the end portion of the primary molded product (92). When the secondary mold is closed, the primary molded product holding portion (30) withdraws from the second cavity (C2), and the sliding portion (40) slides relative to the primary molded product holding portion (30) and protrudes into the second cavity (C2), partitioning the second cavity (C2).

Description

Technical Field

[0001] The present disclosure relates to a mold device and an injection molding method. Background Art

[0002] Currently, as a method of injection molding, a method of injection molding a two-color molded product in which a secondary molded product made of a second resin is disposed around a primary molded product made of a first resin is known.

[0003] In Patent Document 1 and Patent Document 2, a technique for injection molding a two-color molded product using a rotating member that can be rotatably disposed around an axis between a primary core mold and a secondary core mold and a cavity mold that can be clamped and opened with respect to the rotating member and fixed to the primary core mold and the secondary core mold is disclosed.

[0004] Generally, a molded product is held in a core mold when the mold is opened. On the other hand, in two-color molding according to the above technique, it is necessary to hold the primary molded product after the primary molding in the cavity mold. Therefore, in Patent Document 1, a primary molded product holding portion that can enter and exit the primary molding space is provided on the cavity mold, and the primary molded product holding portion protrudes into the primary molding space during primary molding, and the primary molded product is held in the cavity mold when the primary molding is opened. Further, in Patent Document 2, a biasing member is included in the primary core mold, and the biasing member biases the primary molded product toward the cavity mold. When the mold is opened after the primary molding, the primary molded product is held in the cavity mold. In addition, in the present specification, the term "protruding into the molding space" includes not only protruding into the molding space but also abutting against the boundary of the molding space to divide a part of the molding space.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-168936

[0008] Patent Document 2: International Publication No. 2018 / 016323 Pamphlet Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, in the case of Patent Document 1, there is a problem of insufficient aesthetics due to the traces of the locking portions of the access components remaining on the surface of the finished product. Also, in the case of Patent Document 2, in order to apply force, there is a case where ribs need to be provided on the outer edge portion of the primary molded product, and due to these ribs, there is a problem of insufficient aesthetics in appearance. In addition, these ribs may interfere with the sliding portions for undercuts, and undercuts cannot be provided in this part. Therefore, there is a problem that design limitations occur and diverse design requirements cannot be met.

[0011] An object of the present disclosure is to provide a new technique for holding a primary molded product in a cavity mold in two-color molding.

[0012] Means for Solving the Problem

[0013] To achieve the above object, a mold device according to an embodiment of the present disclosure includes a primary mold formed by a cavity mold and a primary core mold, and a primary molded product is formed by injecting a first resin material into a first cavity formed by closing the cavity mold and the primary core mold; a secondary mold formed by the cavity mold and a secondary core mold, and a secondary molded product is laminated and formed on the peripheral portion of the primary molded product by injecting a second resin material into a second cavity formed by closing the cavity mold holding the primary molded product and the secondary core mold; the cavity mold includes a primary molded product holding portion that can enter and exit relative to the first cavity on the parting line of the primary mold, the secondary core mold includes a sliding portion that can enter and exit relative to the second cavity on the parting line of the secondary mold and has a shape complementary to the primary molded product holding portion, at the time of mold opening in the primary molding, the primary molded product holding portion protruding into the first cavity holds the primary molded product in the cavity mold by locking the end face of the primary molded product, at the time of mold closing in the secondary molding, the primary molded product holding portion withdraws from the second cavity, and the sliding portion slides relative to the primary molded product holding portion and protrudes into the second cavity, thereby dividing the second cavity.

[0014] An injection molding method related to an embodiment of the present invention is an injection molding method for a two-color molded product in which a secondary molded product is laminated on the peripheral portion of a primary molded product. The method includes the steps of closing a cavity mold and a primary core mold, and at the parting line, dividing a first cavity by protruding a primary molded product holding portion provided on the cavity mold and capable of entering and exiting the first cavity; injecting a first resin material into the first cavity to form the primary molded product; the primary molded product holding portion clamping the end of the peripheral portion of the primary molded product to hold the primary molded product in the cavity mold, and then opening the primary mold; closing the cavity mold holding the primary molded product and a secondary core mold to divide a second cavity. In this step, the primary molded product holding portion withdraws from the second cavity and on the parting line of the secondary mold, a sliding portion capable of entering and exiting the second cavity and having a shape complementary to the primary molded product holding portion slides with the primary molded product holding portion and protrudes into the second cavity to divide the second cavity; injecting a second resin material into the portion of the second cavity excluding the primary molded product to form the secondary molded product.

[0015] Effects of the Invention

[0016] According to the mold and injection molding method related to the foregoing embodiment, in two-color molding, the primary molded product can be held in the cavity mold after primary molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a front view of a two-color molded product formed by using the injection molding method of the present embodiment.

[0018] Figure 2 is along the Figure 1 in the two-color molded product.

[0019] Figure 3 is a schematic cross-sectional view of a mold device used in the injection molding method of the present embodiment.

[0020] Figure 4A is a schematic cross-sectional view of the mold device during the mold closing of the primary molding in the injection molding method of the present embodiment.

[0021] Figure 4B is a schematic cross-sectional view of the mold device during the mold opening of the primary molding in the injection molding method of the present embodiment.

[0022] Figure 5A is a schematic cross-sectional view of the mold device during the mold closing of the secondary molding in the injection molding method of the present embodiment.

[0023] Figure 5BIt is a schematic cross-sectional view of a mold device during mold opening in the secondary molding of the injection molding method of this embodiment.

[0024] Figure 6 It is an enlarged view of the molded product holding structure of the primary mold of the mold device in the abutting state.

[0025] Figure 7 It is an enlarged view of the molded product holding structure of the secondary mold of the mold device in the abutting state.

[0026] Figure 8A It is an enlarged perspective view of the primary molded product holding portion of the mold device.

[0027] Figure 8B It is a front view of the primary molded product holding portion of the mold device.

[0028] Figure 8C It is from the same direction as Figure 8A An enlarged perspective view of the positioning member of the primary molded product holding portion of the mold device is observed.

[0029] Figure 9 It is a detailed explanatory view of the operation of the primary molded product holding portion during the primary molding in the injection molding method of this embodiment.

[0030] Figure 10A It is an explanatory view of the operation of the primary molded product holding portion during the primary molding in the injection molding method of this embodiment.

[0031] Figure 10B It is an explanatory view of the operation of the primary molded product holding portion during the primary molding in the injection molding method of this embodiment.

[0032] Figure 11 It is an explanatory view of the operation of the primary molded product holding portion during the secondary molding in the injection molding method of this embodiment.

[0033] Figure 12A It is an explanatory view of the operation of the primary molded product holding portion during the secondary molding in the injection molding method of this embodiment.

[0034] Figure 12B It is an explanatory view of the operation of the primary molded product holding portion during the secondary molding in the injection molding method of this embodiment.

[0035] Figure 13 It is an enlarged view of the molded product holding structure of the primary mold of the mold device in the abutting state of the modified example of this embodiment.

[0036] Figure 14 It is an enlarged view of the molded product holding structure of the secondary mold of the mold device in the abutting state of this modified example. Detailed implementation mode

[0037] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, the same names are assigned to equivalent elements, and the constituent elements that are not particularly mentioned are the same constituent elements and repeated descriptions thereof may be appropriately omitted. In addition, in each drawing, the dimensional ratios of the respective components do not necessarily match the actual dimensional ratios.

[0038] (Two-color molded product)

[0039] First, the structure of the mold device 100 of the present embodiment and the two-color molded product 90 formed by the injection molding method will be described. Figure 1 FIG. is a front view of the two-color molded product 90. Figure 2 It is Figure 1 a partial cross-sectional view taken along line II-II.

[0040] The two-color molded product 90 is a front cover assembled to the front opening of a lamp body of a vehicle lamp such as a headlamp. The two-color molded product 90 includes a front portion 90a and a peripheral surface portion 90b extending rearward from the outer peripheral edge of the front portion 90a.

[0041] The two-color molded product 90 is configured such that the secondary molded product 94 is disposed around the primary molded product 92. The primary molded product 92 is made of a first resin material R1 (transparent resin). The secondary molded product 94 is made of a second resin material R2 (opaque (specifically, black) resin). The two-color molded product 90 is formed such that the primary molded product 92 and the secondary molded product 94 partially overlap at the peripheral surface portion 90.

[0042] (Mold device)

[0043] Figure 3 FIG. is a cross-sectional view schematically showing the mold device 100 using the injection molding method of the present embodiment. The mold device 100 is configured as a so-called opposed-type two-color molding die.

[0044] The mold device 100 includes a primary core mold 10 and a secondary core mold 12 disposed opposite to each other along the X-axis extending in the horizontal direction; a rotating member 14 disposed between the primary core mold and the secondary core mold and rotatable about the Y-axis orthogonal to the X-axis and extending in the vertical direction; a pair of cavity molds 16 of the same shape fixed to the rotating member 14 in a state of sandwiching the Y-axis; a first movable disk 18 supporting the primary core mold 10 and a second movable disk 20 supporting the secondary core mold 12.

[0045] The primary core mold 10 and the secondary core mold 12 are so-called movable molds, and the pair of cavity molds 16 are so-called fixed molds.

[0046] The first movable disk 18 is configured to be movable in the X-axis direction with respect to the rotating member 14 as shown by the arrow A1. The second movable disk 20 is also configured to be movable in the X-axis direction with respect to the rotating member 14 as shown by the arrow A2.

[0047] The mold device 100 injects the first resin material R1 supplied from the first heating cylinder 22 supported by the first movable disk 18 into the first cavity C1 formed between the primary core mold 10 and the cavity mold 16 that abut against each other by mold clamping, to form the primary molded product 92. In addition, the second resin material R2 supplied from the second heating cylinder 24 supported by the second movable disk 20 is injected into the portion of the second cavity C2 formed between the secondary core mold 12 and the cavity mold 16 that abut against each other by mold clamping, excluding the primary molded product 92, to form the secondary molded product 94. Therefore, one of the primary core mold 10 and the cavity mold 16 constitutes the primary mold 26, and the other of the secondary core mold 12 and the cavity mold 16 constitutes the secondary mold 28.

[0048] The cavity mold 16 has a cavity chuck 30 as a primary molded product holding portion at the peripheral portion of the first cavity C1. In addition, the cavity mold 16 includes a cam pin 34 that projects toward the core mold 10 or the secondary core mold 12 while inclining away from the X-axis toward the outside of the cavity chuck 30.

[0049] On the other hand, the primary core mold 10 has a fixed pin 32 that matches the shape of the cavity chuck 30 at a position opposed to the cavity chuck 30. In addition, at a position on the primary core mold 10 corresponding to the cam pin 34, there is a pin insertion portion 38 that functions as a first pin insertion hole.

[0050] Moreover, the secondary core mold 12 has a sliding portion 40 at a position opposed to the cavity chuck 30. And at a position on the secondary core mold 12 corresponding to the cam pin 34, there is a pin insertion hole 40e that functions as a second pin insertion hole.

[0051] The cavity block 30, the fixing pin 32, the angled guide pin 34, the pin insertion part 38, and the pin insertion hole 40e cooperate with each other. When the first mold 26 is opened, the first formed product 92 is held in the cavity mold 16. When the second mold 28 is opened, the two-color formed product 90 is held in the second core mold 12. That is to say, the cavity block 30, the fixing pin 32, the angled guide pin 34, the pin insertion part 38, and the pin insertion hole 40e function as a formed product holding structure. One or more formed product holding structures are provided as needed at the peripheral part of the first mold 26 and the second mold 28. The detailed operation of the formed product holding structure will be described later. It should be noted that in the description of the formed product holding structure, unless otherwise specified, the direction along the Y-axis toward the forming space (the first cavity C1) is defined as the front, and the direction along the Y-axis toward the outside of the mold device 100 is defined as the rear.

[0052] (Outline of the injection molding method)

[0053] Here, the outline of the injection molding method of the present embodiment will be described. First, as Figure 4A shown, by moving the first movable disk 18 and the second movable disk 20 toward the rotating member 14, the first core mold 10 and the second core mold 12 are clamped with a pair of cavity molds 16. As a result, the first core mold 10 and the cavity mold 16 abut against each other, and a first cavity C1 is formed therebetween. At this time, the cavity block 30 slightly protrudes into the first cavity C1, and the front end of the cavity block 30 constitutes a part of the first cavity C1. And by injecting the first resin material R1 from the first heating cylinder 22 supported by the first movable disk 18 into the first cavity C1, the first formed product 92 is formed.

[0054] Next, as Figure 4B shown, the first core mold 10 and the second core mold 12 are opened from the pair of cavity molds 16. At this time, the first formed product 92 adheres to the first core mold 10 due to the shrinkage effect of the first resin material R1. However, since the cavity block 30 provided on the cavity mold 16 engages with the end face of the peripheral part of the first formed product 92, the first formed product 92 cannot be separated from the cavity mold 16. Thus, the first formed product 92 is detached from the first core mold 10 while being held in the cavity mold 16.

[0055] Next, in this state, the rotating member 14 is rotated 180° around the Y-axis. At this time, centrifugal force acts on the first formed product 92 held in the cavity mold 16 that rotates together with the rotating member 14, but since the first formed product 92 is locked by the cavity block 30, it is held in the cavity mold 16. Thus, the cavity mold 16 of the present embodiment functions as a holding mold that holds the first formed product 92 when the mold is opened.

[0056] Next, asFigure 5A As shown, by moving the first movable disk 18 and the second movable disk 20 in the direction of the rotating member 14, the primary core mold 10 and the secondary core mold 12 are clamped with the pair of cavity molds 16. Thus, on one side of the secondary mold 28, the secondary core mold 12 abuts against the cavity mold 16 holding the primary molded product 92 to form the second cavity C2. At this time, as the cavity block 30 retracts from the second cavity C2, the sliding portion 40 advances toward the side of the second cavity C2, and the front end of the sliding portion 40 forms a part of the second cavity C2. In this state, by injecting the second resin material R2 supplied from the second heating cylinder 24 into the portion of the second cavity C2 other than the primary molded product 92, the secondary molded product 94 is formed. Thus, the two-color molded product 90 integrated by the primary molded product 92 and the secondary molded product 94 is manufactured.

[0057] At this time, on one side of the primary mold 26, Figure 4A the primary molded product 92 is formed in the same manner.

[0058] Next, as Figure 5B shown, the primary core mold 10 and the secondary core mold 12 are separated from the pair of cavity molds 16. On one side of the secondary mold 28, since the two-color molded product 90 and the cavity block 30 are not engaged, the two-color molded product 90 is in a state of adhering to the secondary core mold 12 when the mold is opened. And, by an ejector pin (not shown in the figure), the two-color molded product 90 adhering to the secondary core mold 12 is ejected, and is grasped by a take-out machine (not shown in the figure), and the two-color molded product 90 is taken out from the secondary mold 28.

[0059] At this time, on one side of the primary mold 26, Figure 4B the primary molded product 92 is held in the cavity mold 16 by the cavity block 30 in the same manner.

[0060] Next, by rotating the rotating member 14 by 180° about the Y axis, it returns to the state as Figure 5A shown. By repeating this operation, the two-color molded product 90 is continuously manufactured.

[0061] (Molded Product Holding Structure)

[0062] Next, the molded product holding structure will be described in detail.

[0063] Figure 6 is a cross-sectional view showing the molded product holding structure in a state where the primary core mold 10 of the primary mold 26 abuts against the cavity mold 16. Figure 7It is a cross-sectional view showing the molded product holding structure when the secondary core mold 12 of the secondary mold 28 is in contact with the cavity mold 16. It should be noted that, for ease of understanding, in the following drawings, the primary mold 26 and the secondary mold are shown on the left, and the cavity mold 16 is shown on the right.

[0064] in addition, Figure 8A It is a three-dimensional view of the cavity block 30. Figure 8B It is a front view showing a state where the cavity block 30 is assembled into the cavity mold 16 . Figure 8C It is from Figure 8A A three-dimensional view of the positioning component 30i of the cavity block 30 viewed from the same direction.

[0065] like Figure 6 , Figure 8A , Figure 8B As shown, the cavity block 30 has a Figure 6 Below ( Figure 8A The front end portion 30a of the mold block 30 is a thin bird's beak-shaped front end portion 30a, and a three-dimensional cavity block body 30d formed by moving the cross section in a direction orthogonal to the cross section by means of a concave portion 30b having a valley-shaped cross section and a convex portion 30c having a mountain-shaped cross section. The angle of the front end of the front end portion 30a is appropriately set in consideration of the mold strength, preferably about 45°. The valley-shaped concave portion 30b and the mountain-shaped convex portion 30c form the concave-convex structure of the cavity block 30.

[0066] like Figure 8B As shown, a groove is formed at the lower end of the cavity block body 30d. Figure 8B The widening portion 30g is widened in the left and right directions. A pressing plate 30e is arranged on the left and right sides of the paper surface of the cavity block body 30d. The pressing plate 30e extends along the upper end of the widening portion 30g, and holds the cavity block body 30d in the cavity block mounting recess 29 of the cavity mold 16 so that it can move in the front-back direction. Three through holes (not shown) arranged in series in the depth direction of the paper surface are respectively provided on each pressing plate 30e.

[0067] The bottom surface of the cavity block body 30d is formed with an edge Figure 8B The triangular groove 30h is V-shaped and extends in the left-right direction. Figure 8B There are 1 pair of 2 positions on the front side and the inner side in the paper depth direction, for a total of 4 positions. The distance between a pair of triangular grooves 30h is set to be equivalent to the movement distance of the cavity block 30 described later in the paper depth direction. The cavity block 30 includes two positioning components 30i arranged at intervals in the paper depth direction. Figure 8CAs shown, the positioning member 30i generally has a cylindrical shape, and a threaded insertion hole 30i1 is formed above the paper surface. In addition, it has a cross-section along the plane in the front-rear direction that is approximately triangular, and a triangular convex portion 30i2 that extends in the left-right direction of the paper surface in Figure 8B and protrudes upward. The positioning member 30i includes a spring 30i3 inside (refer to Figure 8B ). The triangular convex portion 30i2 is upwardly urged by the spring 30i3 and protrudes upward from the elliptical window provided on the upper surface of the positioning member 30i. The triangular convex portion 30i2 is configured to be hidden inside the housing of the positioning member 30i when a pressing force acts from above the positioning member 30i.

[0068] As Figure 6 、 Figure 7 shown, in the cavity block mounting recess 29, two cylindrical recesses 31 corresponding to the positioning member 30i are provided in the front-rear direction. The positioning member 30i is mounted in the recess 31 by mounting screws 30j. The cavity block body 30d is configured such that the triangular groove 30h and the triangular convex portion 30i2 correspond. The left and right pressing plates 30e are respectively arranged along the upper ends of the widened portions 30g on both sides, and are connected to the cavity die 16 by three bolts 30f on each side via pressing plate through holes (not shown). Thus, the cavity block 30 is fixed to the cavity die 16. The cavity block body 30d slides inside the cavity block mounting recess 29 and can move in the front-rear direction ( Figure 6 and Figure 7 in, the front direction and the rear direction correspond to the lower direction and the upper direction of the paper surface respectively) move. The triangular convex portion 30i2 of the positioning member 30i is pressed down by its bottom surface during the movement of the cavity block body 30d. Thus, the movement of the cavity block body 30d is not hindered. As Figure 6 shown, at the maximum forward position of the cavity block body 30d (hereinafter, referred to as the “forward limit (of the cavity block 30)”).), the protruding triangular convex portion 30i2 of the positioning member 30i engages with the rear triangular groove 30h in each pair of triangular grooves 30h. In addition, as Figure 7 shown, at the maximum backward position of the cavity block body 30d (hereinafter, referred to as the “backward limit (of the cavity block 30)”).), the protruding triangular convex portion 30i2 of the positioning member 30i engages with the front triangular groove 30h in each pair of triangular grooves 30h. Thus, the cavity block body 30d is positioned. It should be noted that the number and arrangement of the triangular grooves 30h and the triangular convex portions 30i2 for positioning are not limited to the examples of this embodiment as long as the cavity block body 30d is positioned at the forward limit and the backward limit. For example, two triangular convex portions 30i2 may be provided on the front and rear of the positioning member 30i, and one triangular groove 30h may be provided on the bottom surface of the cavity block body 30d.

[0069] Behind the cavity block 30 in the cavity mold 16, there is an inclined guide pin 34 that is inclined away from the X-axis and protrudes toward the primary core mold 10. The inclined guide pin 34 is inserted into a rectangular fixing block 35 having a pin holding hole 35a. In this state, by embedding the fixing block 35 into the cavity mold 16, the inclined guide pin 34 is installed in the cavity mold 16 such that the front end of the inclined guide pin 34 protrudes toward the primary core mold 10. The fixing block 35 is fixed to the cavity mold 16 by a known method (such as bolts). The head 34a of the inclined guide pin 34 has a larger diameter than the pin body 34b, and the head 34a prevents the inclined guide pin 34 from falling out of the pin holding hole 35a.

[0070] A fixing pin 32 having a mountain-shaped convex portion 32b and a valley-shaped concave portion 32c is installed at a position of the primary core mold 10 opposite to the cavity block 30. The convex portion 32b and the concave portion 32c constitute the concavo-convex structure of the fixing pin 32. The concavo-convex structure of the fixing pin 32 is complementary to the concavo-convex structure of the cavity block 30. That is, the concavo-convex structure of the fixing pin 32 is configured to be combinable in a state where it faces the concavo-convex structure of the cavity block 30. Similar to the cavity block 30, the fixing pin 32 also has a three-dimensional shape formed by translating the Figure 6 shown cross-section. A concave portion 33 complementary to the three-dimensional shape of the fixing pin 32 is provided in the primary core mold 10. Similar to the fixing block 35, the fixing pin 32 is fixed to the primary core mold 10 by a known method (such as bolts) in a state of being fitted into the concave portion 33.

[0071] Behind the fixing pin 32 of the primary core mold 10, there is a pin insertion portion 38. The width of the pin insertion portion 38 in a direction orthogonal to the cross-section is slightly larger than the diameter of the inclined guide pin 34, and it has an opening portion with a length in the front-rear direction that can ensure the channel length of the inclined guide pin 34. The pin insertion portion 38 is configured to be able to accommodate the inclined guide pin 34 that protrudes as the molds are closed. In the abutting state of the primary core mold 10 and the cavity mold 16, the front end portion 30a (the front end) of the cavity block 30 and the primary core mold 10 and the cavity mold 16 together form a first cavity C1.

[0072] On the other hand, as Figure 7As shown, a sliding portion 40 is installed at a position of the secondary core mold 12 opposite to the cavity block 30. The sliding portion 40 includes a fixing pin portion 40d composed of a convex portion 40b and a concave portion 40c having the same shape as the fixing pin 32. The sliding portion 40 further extends rearward from the fixing pin portion 40d and includes a pin insertion hole 40e having a cylindrical shape with a diameter slightly larger than that of the angled pin 34 at a position corresponding to the angled pin 34. The sliding portion 40 is slidably installed on the secondary core mold 12 in the front-rear direction by a known method similar to that of the outer sliding portion of a conventionally known injection molding die. In addition, a pin insertion portion 42 having the same shape as the pin insertion portion 38 is provided at a position corresponding to the pin insertion hole 40e of the secondary metal core mold 12.

[0073] (Detailed description of the operation of the molded product holding structure)

[0074] Figure 9 It is a diagram for a detailed description of the operation of the molded product holding structure from the start of the first molding clamping to the mold opening, that is, the cavity block 30, the fixing pin 32, and the angled pin 34.

[0075] As Figure 9 shown, at the start of the clamping, the cavity block 30 is at the retraction limit, and the concave portion 30b and the convex portion 30c of the cavity block 30 are offset by a predetermined distance in a direction orthogonal to the X-axis from the convex portion 32b and the concave portion 32c of the fixing pin 32.

[0076] Then, with the clamping operation, the angled pin 34 is inserted into the pin insertion portion 38.

[0077] At this time, as Figure 10A shown in the enlarged view, when the rear inclined surface 32c2 of the concave portion 32c of the fixing pin 32 advances in the arrow direction parallel to the X-axis (left-right direction of the paper surface), it abuts against the rear inclined surface 30c2 of the convex portion 30c of the cavity block 30. Thereby, the rear inclined surface 30c2 pushes the cavity block 30 forward (downward in the paper surface), and the cavity block body 30d is guided by the mounting plate 30e and moves forward.

[0078] And when the rear triangular groove 30h in each pair of triangular grooves 30h advances to its forward limit where it engages with the triangular convex portion 30i2 of the positioning member 30i, the primary core mold 10 abuts against the cavity mold 16. Then, the concave-convex structure (concave portion 30b and convex portion 30c) of the cavity block 30 is combined with the concave-convex structure (convex portion 32b and concave portion 32c) of the fixing pin 32 to stop the cavity block 30 from advancing. At this time, the front end of the front end portion 30a of the cavity block 30 slightly protrudes into the interior of the first cavity C1 to demarcate a part C1 of the first cavity C1. Thus, a parting line PL is formed between the front end portion 30a of the cavity block 30 and the secondary core mold 12 (refer to Figure 9(Contact state). Then, the first resin material R1 is injected from the first heating cylinder 22 to form the primary molded product 92.

[0079] Next, when the mold is opened, as the primary core mold 10 moves in the direction away from the cavity mold 16, the pin insertion part 38 moves in the direction away from the angled pin 34, and the angled pin 34 is pulled out from the pin insertion part 38. Similarly, the fixing pin 32 also moves away from the cavity block 30, but without the interaction during mold closing, and the front end part 30a of the cavity block 30 remains in the state of the forward limit.

[0080] At this time, as magnified in Figure 10B , the front end of the front end part 30a of the cavity block 30 engages with a part of the end face of the peripheral part of the primary molded product 92. When the mold is opened and the rotating member 14 rotates subsequently, the front end of the front end part 30a holds the primary molded product 92 in the cavity mold 16 and prevents the primary molded product 92 from detaching from the cavity mold 16.

[0081] (Operation of the molded product holding part during secondary molding)

[0082] Figure 11 、 Figure 12A and Figure 12B are detailed descriptions of the operations of the cavity block 30, the sliding part 40, and the angled pin 34, which are the molded product holding structures from the start of mold closing to mold opening during secondary molding.

[0083] As Figure 11 shown, at the start of mold closing, the cavity block 30 is in a state of being offset forward with respect to the positioning member 30i fixed to the cavity mold 16 (the cavity block body 30d is in the forward limit state). And, along with the mold closing operation, as the angled pin 34 advances inside the pin insertion hole 40e, the sliding part 40 starts to advance. At the same time, as Figure 12A shown, through the abutment of the rear inclined surface 40c1 of the concave part 40c of the fixing pin part 40d and the front inclined surface 30c1 of the convex part 30c of the cavity block 30, the cavity block 30 is made to retreat relative to the cavity mold 16 by the interaction.

[0084] And, when the front triangular groove 30h in each pair of triangular grooves 30h advances to the retreat limit where it engages with the triangular convex part 30i2 of the positioning member 30i, the secondary core mold 12 abuts against the cavity mold 16. As magnified in Figure 12B , the front end part 30a of the cavity block 30 retreats from the second cavity C2 and stops. Moreover, the front end part 40a of the sliding part 40 and the primary molded product 92 and the secondary core mold 12 together define the formation space of the secondary molded product 94, and the abutment surface of the front end part 40a of the sliding part 40 and the cavity mold 16 forms the parting line PL.

[0085] Next, with the mold opening operation, while the secondary core mold 12 moves in a manner of separating from the cavity mold 16, the angled pin 34 is released from the pin insertion hole 40e. At the same time, the sliding portion 40 retracts. Meanwhile, the engagement between the fixed pin portion 40d and the concave and convex portions of the cavity block 30 is released, and the sliding portion 40 separates from the cavity block 30. However, without the interaction during mold closing, the cavity block body 30d remains in the state of the retraction limit.

[0086] Thus, the mold device 100 is configured to include a cavity block 30 that can move in and out of the first cavity C1 and a sliding portion 40 that can move in and out of the second cavity C2. During the mold closing of the primary forming, at the parting line PL, the front end of the front end portion 30a of the cavity block 30 protrudes into the first cavity C1 as the forming space, thereby partitioning the first cavity C1. During the mold opening of the primary forming, the front end portion 30a holds the primary formed product 92 by engaging with the end surface at the peripheral portion to hold the primary formed product 92 in the cavity mold 16. Further, during the mold closing of the secondary forming, the cavity block 30 and the sliding portion 40 slide relative to each other, causing the cavity block 30 to retract from the forming space and the sliding portion 40 to advance. The second cavity C2 is defined by the front end of the sliding portion 40, the secondary core mold 12, and the cavity mold 16.

[0087] According to the above structure, the cavity block 30 holds the primary formed product 92 at the parting line PL, that is, the end surface of the peripheral portion, and holds it in the cavity mold 16. Therefore, in the two-color formed product 90, the trace of the cavity block 30 is not obvious, and the aesthetics of the two-color formed product 90 is improved. Here, the cavity block 30 does not necessarily need to engage with the entire region in the end surface thickness direction. As Figure 10B shown in the enlarged view, it can also engage with a part of the end surface thickness direction. This is because the smaller the engagement amount, the smaller the trace of the cavity block 30 remaining on the two-color formed product 90, and it will be less obvious.

[0088] In addition, currently, there is no need to provide ribs or flanges that are only provided to hold the cavity mold 16 after the primary forming. In this regard, the appearance of the two-color formed product 90 is improved. Further, since the cavity block 30 that holds the primary formed product 92 at the parting line PL and the outer sliding portion of the secondary core mold 12 can coexist, a structure necessary for undercuts can be provided on the secondary formed product 94. Thus, diverse designs can be satisfied, and the creativity of the two-color formed product 90 is improved.

[0089] In particular, in the present embodiment, the cavity block 30 and the sliding portion 40 include a shape-matched concave-convex structure (respectively, a fixing pin 32 including a concave portion 30b and a convex portion 30c of the cavity block 30 and a fixing pin portion 40d including a convex portion 40b and a concave portion 40c of the sliding portion 40). With the mold closing and mold opening actions, the cavity block 30 can move in the front-to-back direction by cooperating with the concave-convex structure of the cavity block 30 and the concave-convex structure of the sliding portion 40. The action structure of the cavity block 30 is not limited to the above-mentioned structure. However, through the above-mentioned structure, there is no need to equip the cavity block 30 with a driving structure such as a motor and a hydraulic cylinder, which can simplify the structure of the mold 100 and reduce the manufacturing cost.

[0090] In addition, in this embodiment, the concavo-convex structure of the cavity block 30 and the concavo-convex structure of the fixing pin 32 cooperate with each other. The fixing pin 32 is a structure generally required in the mold device 100 to prevent positional deviation between the fixed mold and the movable mold, and is not a structure newly required due to the introduction of the cavity block 30. In this regard, the mold device 100 is also prevented from being overly complicated.

[0091] Furthermore, in the present embodiment, the cavity mold 16 includes an inclined guide pin 34 inclined relative to the moving direction of the movable mold. Through the sliding structure of the inclined guide pin 34 and the sliding part 40, the sliding part 40 can move in the front-back direction with the mold closing and mold opening actions. Through the above structure, the sliding part 40 is linked to the action of mold opening and mold closing, and the cavity block 30 can be withdrawn from the second cavity C2 by the action of the sliding part 40. Therefore, there is no need to equip a driving structure for moving the sliding part 40 and the cavity block 30. The structure of the mold device 100 can be simplified and the manufacturing cost can be reduced.

[0092] In addition, in the above-mentioned embodiment, the fixing pin 32 and the inclined guide pin 34 are respectively constituted as components independent of the primary core mold 10 and the cavity mold 16, and are respectively fixed to the primary core mold 10 and the cavity mold 16. However, these components that do not move with the action of mold closing and mold opening can also be formed integrally with the primary core mold 10 and the cavity mold 16.

[0093] (Variation Example)

[0094] As described above, the mold device 100 drives the cavity block 30 by the interaction between the fixing pin 32 and the cavity block 30 during the primary molding, and drives the sliding portion 40 by the inclined guide pin 34 during the secondary molding, and drives the cavity block 30 by the interaction between the sliding portion 40 and the cavity block 30. However, in the present disclosure, the cavity block 30 and the sliding portion 40 may also be driven by a driving structure that controls the cavity block 30 and the sliding portion 40 separately.

[0095] Figure 13 is an enlarged view of a molded product holding structure in a contact state of a primary mold corresponding to one of such modified examples of the mold device 100A Figure 6 with respect to the mold device 100A. Figure 14 is an enlarged view of a molded product holding structure in a contact state of a secondary mold corresponding to the same modified example Figure 7 of the mold device 100A.

[0096] The primary mold 26A of the mold device 100A includes a primary core mold 10A and a cavity mold 16A. The cavity mold 16A includes a cavity block 30A as a primary molded product holding portion. The cavity block 30A includes a positioning member 30i having the same configuration as the cavity block 30. On the other hand, different from the cavity block 30, the cavity block 30A includes a cavity block body 30Ad having a substantially trapezoidal cross-sectional shape, and the cavity block body 30Ad has an inclined surface 30Ab inclined forward toward the first cavity C1. The cavity block 30A has a beak-shaped front end portion 30Aa that is thinner in the front direction.

[0097] In addition, in Figure 13 the contact state shown, the front end portion 30Aa of the cavity block 30A protrudes in the form of an end surface that demarcates the peripheral portion of the first cavity C1 corresponding to the primary molded product 92 on the parting line PL.

[0098] The cavity block 30A can move in the front-rear direction orthogonal to the X-axis with respect to the cavity mold 16 by the same structure as the cavity block 30.

[0099] The cavity mold 16A is different from the cavity mold 16 in that it does not have a cam pin 34, but has a hydraulic cylinder 52 connected to the cavity block 30A on the outside of the cavity block 30A. The hydraulic cylinder 52 can move the cavity block 30A in the front-rear direction indicated by the double arrow through the control of a control unit (not shown).

[0100] The primary core mold 10A does not need to be provided with a fixing pin at a position opposite to the cavity block 30A. At a position opposite to the cavity block 30A of the primary core mold 10A, in the contact state, an inclined surface 54 that is complementary and matches the inclined surface 30Ab of the cavity block 30A is formed. In addition, in the contact state of the primary mold, the cavity block 30A is disposed at the forward limit position. The primary core mold 10A also does not need to be equipped with a pin insertion portion 38 that functions as a first pin insertion hole.

[0101] As Figure 14As shown, the secondary mold of the mold device 100A includes a secondary core mold 12A and a cavity mold 16A. The secondary core mold 12A includes a replacement sliding portion 40 and a sliding portion 40A that can slide in the front-rear direction orthogonal to the X-axis direction. The sliding portion 40A is not equipped with a fixed pin portion 40d. The sliding portion 40A includes an inclined surface 40Ab that is complementary and matches the inclined surface 30Ab of the cavity block 30A. The sliding portion 40A has a three-dimensional shape with a substantially trapezoidal cross-sectional shape. The front end portion 40Aa of the sliding portion 40A protrudes into the second cavity C2 and, together with the primary molded product 92 and the secondary core mold 12A, defines the second cavity C2.

[0102] The secondary core mold 12A is not equipped with a pin insertion hole 40e and a pin insertion portion 42 that serve as the second pin insertion hole. However, the secondary core mold 12A includes a hydraulic cylinder 56 connected to the sliding portion 40A behind the sliding portion 40A. The hydraulic cylinder 56 can move the sliding portion 40A in the front-rear direction orthogonal to the X-axis direction without passing through the angle pin 34.

[0103] In the abutting state of the secondary mold 28A, the cavity block 30A is located at the retraction limit position where the front end portion 30Aa withdraws from the forming space.

[0104] Moreover, during the mold closing of the primary molding, as the mold closing operation progresses, the mold device 100A controls the hydraulic cylinder 52 to advance the cavity block 30A to the forward limit and project it into the first cavity C1 on the parting line PL. Next, the mold device 100A injects the first resin material R1 into the first cavity C1 to form the primary molded product 92. Then, the mold device 100A opens the mold in a state where the front end portion 30A of the cavity block 30A is stuck to the end surface of the peripheral portion of the primary molded product 92 and rotates the rotating member 14 by 180°.

[0105] Next, as the mold closing operation of the secondary molding progresses, the mold device 100A controls the hydraulic cylinder 52 to retract the cavity block 30A from the forward limit and, at the same time, controls the hydraulic cylinder 56 to advance the sliding portion 40A. The cavity block 30A and the sliding portion 40A can slide relative to each other during the retraction of the cavity block 30A and the advancement of the sliding portion 40A through the inclined surfaces 30Ab and 40Ab, enabling smooth movement. As a result, the front end portion 40Aa protrudes into the second cavity C2, defining the second cavity C2. Then, the mold device 100A injects the second resin material R2 into the portion of the second cavity C2 other than the primary molded product 92 to form the secondary molded product 94. After that, the mold device 100A opens the mold and takes out the formed two-color molded product 90.

[0106] Thus, even when using a drive structure that additionally controls the cavity block 30A and the sliding portion 40A of the molded product holding structure, the cavity block 30A of the primary core mold 10A and the sliding portion 40A of the secondary core mold 12A form complementary shapes that match each other in the abutting state. At the time of mold clamping for the primary molding, the cavity block 30A projects into the molding space (the first cavity C1). At the time of mold opening, the front end portion 30Aa of the cavity block 30A abuts against the end face of the peripheral portion of the primary molded product 92. Similarly to the mold apparatus 100, the mold apparatus 100A can hold the primary molded product 92 in the cavity mold 16A after the primary molding. Further, at the time of mold clamping for the secondary molding, due to the complementary shapes of the cavity block 30A and the sliding portion 40A, the mold apparatus 100A can simultaneously retract the cavity block 30A and advance the sliding portion 40A. Therefore, the cavity block 30A and the outer sliding portion can coexist.

[0107] In addition, the drive structure for driving the cavity block 30A and the sliding portion 40A is not limited to a hydraulic cylinder. For example, a motor can also be used as the drive structure.

[0108] The above is a description of a preferred embodiment of the present disclosure. However, the above embodiment is only one example of the disclosure and is not limited to this example.

[0109] This application appropriately incorporates the content disclosed in the Japanese patent application (Patent Application No. 2020-210763) filed on December 18, 2020.

Claims

1. A mold device, characterized in that, The mold device includes: A primary mold formed by a cavity mold and a primary core mold, and forming a primary molded product by injecting a first resin material into a first cavity formed by closing the cavity mold and the primary core mold; A secondary mold formed by the cavity mold and a secondary core mold, and laminating and forming a secondary molded product on the peripheral portion of the primary molded product by injecting a second resin material into a second cavity formed by closing the cavity mold holding the primary molded product and the secondary core mold; The cavity mold includes a primary molded product holding portion that can enter and exit relative to the first cavity on the parting line of the primary mold; The secondary core mold includes a sliding portion that can enter and exit relative to the second cavity on the parting line of the secondary mold and has a shape complementary to the primary molded product holding portion; When the primary mold is opened, the primary molded product holding portion protruding into the first cavity holds the primary molded product in the cavity mold by locking the end face of the primary molded product; When the secondary mold is closed, the primary molded product holding portion withdraws from the second cavity, and the sliding portion slides relative to the primary molded product holding portion and protrudes into the second cavity, thereby dividing the second cavity.

2. The mold device according to claim 1, characterized in that, When the primary mold is opened, the front end of the primary molded product holding portion protrudes into the first cavity and holds the primary molded product in the cavity mold by locking a part of the end of the primary molded product.

3. The mold device according to claim 1 or 2, characterized in that, The primary core mold includes fixing pins with an uneven structure along the outer periphery of the first cavity; The primary molded product holding portion has an uneven structure complementary to the fixing pins when the primary mold is closed; The sliding portion includes a fixing pin portion with an uneven structure complementary to the primary molded product holding portion; With the closing movement of the primary mold, through the cooperation of the uneven structure of the fixing pins and the uneven structure of the primary molded product holding portion, the primary molded product holding portion advances into the first cavity and protrudes into the first cavity; The sliding portion advances into the second cavity with the closing movement of the secondary mold; With the closing movement of the secondary mold, through the cooperation of the uneven structure of the fixing pin portion and the uneven structure of the primary molded product holding portion, the primary molded product holding portion withdraws from the second cavity.

4. The mold device according to claim 1 or 2, characterized in that, The cavity mold includes angled guide pins inclined with respect to the moving directions of the primary core mold and the secondary core mold; A first pin insertion hole for inserting the angled guide pins is provided on the primary core mold; A second pin insertion hole for inserting the angled guide pins is provided on the sliding portion; With the closing movement of the secondary mold, the sliding portion advances into the second cavity by inserting the angled guide pins into the second pin insertion hole.

5. An injection molding method, which is an injection molding method for a two-color molded product in which a secondary molded product is laminated on the peripheral portion of a primary molded product, characterized in that, Including: A step of closing the cavity mold and the primary core mold, and on the parting line, dividing the first cavity by protruding the primary molded product holding portion provided on the cavity mold that can enter and exit relative to the first cavity; A step of injecting a first resin material into the first cavity to form the primary molded product; The step of the primary molded product holding portion clamping the end portion of the peripheral portion of the primary molded product to hold the primary molded product in the cavity mold and causing the primary mold to open; The step of closing the cavity mold holding the primary molded product and the secondary core mold to divide a second cavity. In this step, the primary molded product holding portion withdraws from the second cavity and is on the parting line of the secondary mold, and a sliding portion having a shape complementary to the primary molded product holding portion can slide in and out of the second cavity and protrudes into the second cavity to divide the second cavity; The step of injecting a second resin material into the portion of the second cavity from which the primary molded product has been removed to form the secondary molded product.

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