CASTING MOLD AND METHOD FOR CASTING MOLDED ARTICLE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Japanese Patent Application No. 2025-005018 filed on January 14, 2025, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The present disclosure relates to a casting mold and a method for casting a molded article.

Description of Background Art

[0003]Japanese Unexamined Patent Application Publication (JP-A) No. 2004-188470 describes a die casting mold apparatus. The entire contents of this publication are incorporated herein by reference.

SUMMARY OF THE INVENTION

[0004]According to one aspect of the present invention, a casting mold includes a fixed mold including a fixed insert that defines a cavity for a molten mold material, a movable mold that forms the cavity when the fixed and movable molds are closed and includes a movable insert, a slide core, an extrusion pin positioned in the slide core, and an extrusion plate coupled to the extrusion pin and positioned movably with respect to the slide core, a pressing mechanism that presses the extrusion plate in the movable mold toward the movable insert, and a drive mechanism that slides the slide core in the movable mold. The slide core in the movable mold has a storage space that allows the extrusion plate to be movably stored, and the slide core, and the extrusion plate and the extrusion pin are formed such that when the extrusion plate is pressed by the pressing mechanism, the slide core is retracted from a movable insert side by the drive mechanism, the extrusion plate moves within the storage space, and the extrusion pin protrudes from a cavity surface of the slide core.

[0005]According to another aspect of the present invention, a method for casting a molded article includes bringing a restraint positioned on an extrusion plate into contact with a movable insert in a state that the extrusion plate is pressed toward the movable insert, closing a casting mold in a state that the extrusion plate and an extrusion pin are fixed in position, filling a cavity formed by a fixed insert, the movable insert and a slide core with a molten mold material, cooling the mold material such that the mold material is solidified and molded to the molded article, and opening the casting mold such that the molded article is demolded from the cavity formed by the fixed insert, the movable insert and the slide core. The casting mold includes a fixed mold including the fixed insert, and a movable mold including the slide core, the movable insert, the extrusion plate, the extrusion pin and the restraint, and the molded article is demolded such that the extrusion pin protrudes from a cavity surface of the slide core in conjunction with a retraction movement of the slide core, and after an overhang of the molded article is separated from the cavity surface, the slide core retracts the extrusion plate from a movable insert side.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

[0007]FIG. 1 is a perspective view illustrating a casting mold according to an embodiment of the present disclosure;

[0008]FIG. 2 is a perspective view illustrating the casting mold according to the embodiment of the present disclosure;

[0009]FIG. 3 is a cross-sectional view illustrating the casting mold according to the embodiment of the present disclosure;

[0010]FIG. 4 is a cross-sectional view illustrating the casting mold according to the embodiment of the present disclosure;

[0011]FIG. 5 is an exploded perspective view illustrating the casting mold according to the embodiment of the present disclosure;

[0012]FIG. 6 is a cross-sectional view illustrating the casting mold according to the embodiment of the present disclosure;

[0013]FIG. 7 is a cross-sectional view illustrating the casting mold according to the embodiment of the present disclosure; and

[0014]FIG. 8 is a cross-sectional view illustrating the casting mold according to the embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015]Embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.

[0016]First, a casting mold 11 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. A front-rear direction on the paper surface indicates a depth direction of the casting mold 11, a left-right direction on the paper surface indicates a lateral width direction of the casting mold 11, and an up-down direction on the paper surface indicates a height direction of the casting mold 11.

[0017]FIG. 1 is a perspective view illustrating the casting mold 11 according to the present embodiment and illustrates a state in which a fixed mold 13 is viewed from a movable mold 14 side when the mold is opened. FIG. 2 is a perspective view illustrating the casting mold 11 according to the embodiment and illustrates a state in which the movable mold 14 is viewed from the fixed mold 13 side when the mold is opened. FIG. 3 is a cross-sectional view illustrating the casting mold 11 according to the present embodiment and illustrates a cross section of the movable mold 14. FIG. 4 is a cross-sectional view illustrating the casting mold 11 according to the present embodiment and illustrates a cross section of the movable mold 14 taken along an advancing and retracting direction (the front-rear direction on the paper surface) when the mold is closed. FIG. 5 is an exploded perspective view illustrating the casting mold 11 according to the present embodiment and illustrates a positional relationship between a slide core 34 and an extrusion plate 42. FIG. 6 is a cross-sectional view illustrating the casting mold 11 according to the present embodiment and is a schematic diagram illustrating operations of the slide core 34 and an extrusion mechanism 35 when the casting mold 11 is closed. FIGS. 7 and 8 are cross-sectional views illustrating the casting mold 11 according to the present embodiment and are schematic diagrams illustrating operations of the slide core 34 and the extrusion mechanism 35 when the molded article 25 is demolded.

[0018]As illustrated in FIGS. 1 and 2, a casting apparatus 10 mainly includes the casting mold 11 and an injection device 12. The casting apparatus 10 according to the present embodiment is a so-called high-pressure die casting apparatus. In the casting apparatus 10, as a mold material, for example, an alloy of a non-ferrous metal, such as aluminum, zinc, and magnesium, is used. The injection device 12 melts the above-described alloy of the non-ferrous metal, and causes the above-described molten metal to flow into a cavity 40 (see FIG. 4) of the casting mold 11 at a high pressure. The casting mold 11 according to the present embodiment is not limited to being used in the above-described high-pressure die casting apparatus, but may be used as a mold for molding the molded article 25 (see FIG. 4) from the above-described molten metal, in other low-pressure mold apparatuses that use air pressure, gravity mold apparatuses that use gravity, and the like. The casting mold 11 according to the present embodiment can be used as a mold for resin molding.

[0019]The casting mold 11 mainly includes the fixed mold 13, the movable mold 14, a fixed platen 15, a movable platen 16, a base 17, and four tie bars 18. The fixed platen 15 is fixedly disposed on an end of the base 17. The fixed platen 15 supports the fixed mold 13. The tie bars 18 couple the fixed platen 15 and the movable platen 16. The movable platen 16 is guided by the tie bars 18 via a drive mechanism (not illustrated) such as a motor. The movable platen 16 slides with respect to the fixed platen 15 in the advancing and retracting direction (the front-rear direction on the paper surface). The movable platen 16 supports the movable mold 14.

[0020]The fixed mold 13 mainly includes a housing 21, a fixed insert 22, a molten metal supply port 23, and a runner 24 (see FIG. 4). The housing 21 is fixed to an inner surface 15A of the fixed platen 15. The molten metal supply port 23 is formed in the housing 21 below the fixed insert 22. As illustrated in FIG. 4, the injection device 12 is disposed on a rear surface side of the fixed platen 15. Using a plunger 26 of the injection device 12, the injection device 12 causes the above-described molten metal to flow into the cavity 40 from the molten metal supply port 23 via the runner 24 in a high pressure state.

[0021]As illustrated in FIGS. 2 and 3, the movable mold 14 mainly includes a housing 31, a movable insert 32, a position fixing protrusion 33, slide cores 34, extrusion mechanisms 35, and an extrusion mechanism 36 (see FIG. 4). The housing 31 is fixed to an inner surface 16A of the movable platen 16. The movable insert 32 is fixed to an inside of the housing 31. The position fixing protrusion 33 is formed below the movable insert 32. The position fixing protrusion 33 is inserted into the molten metal supply port 23 when the mold is closed.

[0022]As illustrated, slide cores 34 in a pair are disposed in a lateral width direction (the left-right direction on the paper surface) of the casting mold 11. When the casting mold 11 is closed, the slide cores 34 are disposed to sides of the fixed insert 22 (see FIG. 1) and the movable insert 32. The slide cores 34 are members defining the cavity 40. A cavity surface 34A of the slide core 34 faces a cavity surface 22A (see FIG. 1) of the fixed insert 22. The slide cores 34 form a space as the cavity 40 between the fixed insert 22 and the movable insert 32. As will be described in detail later, the slide core 34 slides with respect to the movable insert 32 via the extrusion mechanism 35 in the lateral width direction (the left-right direction on the paper surface) of the casting mold 11.

[0023] The extrusion mechanism 35 mainly includes the extrusion plate 42, extrusion pins 43, a pressing mechanism 44, a drive mechanism 45, and restraints 37. The extrusion plate 42 is movably disposed in a storage space 41 (see FIG. 5) inside the slide core 34. The extrusion pin 43 is disposed on a front side surface 42A of the extrusion plate 42.

[0024]The pressing mechanism 44 is, for example, an extrusion hydraulic cylinder. The pressing mechanism 44 is disposed on a rear surface side of the extrusion plate 42 and is fixed to the housing 31 of the movable mold 14. A cylinder 44A of the pressing mechanism 44 is inserted through the slide core 34. As will be described in detail later, the pressing mechanism 44 has a function of pressing the extrusion plate 42, and does not have a function of pulling the extrusion plate 42. With this structure, the cylinder 44A is disposed in a state of not being coupled to a rear side surface 42B of the extrusion plate 42. The above-described state of not being coupled according to the embodiment refers to a state in which the cylinder 44A and the extrusion plate 42 are not mechanically coupled to each other by bolt fastening or the like.

[0025]As will be described in detail later, when the casting mold 11 is closed, the pressing mechanism 44 operates to extend the cylinder 44A. A tip surface of the cylinder 44A comes into close contact with the rear side surface 42B of the extrusion plate 42. As a result, the extrusion plate 42 is pressed toward the movable insert 32 side. In contrast, the pressing mechanism 44 stops at a predetermined timing when the casting mold 11 is opened. Then, the above-described pressing state of the extrusion plate 42 is eliminated.

[0026]The drive mechanism 45 is, for example, a slide hydraulic cylinder. The drive mechanism 45 is disposed on a rear surface side of the slide core 34 and is fixed to the housing 31 of the movable mold 14. A cylinder 45A of the drive mechanism 45 is coupled to a rear side surface 34E of the slide core 34.

[0027]As will be described in detail later, when the casting mold 11 is closed, the drive mechanism 45 presses the slide core 34 toward the movable insert 32 side by extending the cylinder 45A. The cavity 40 is formed in the casting mold 11 by the slide core 34, the movable insert 32, and the fixed insert 22. At a predetermined timing when the casting mold 11 is opened, the drive mechanism 45 reverses the cylinder 45A in a contracting direction, and the slide core 34 and the extrusion plate 42 retract from the movable insert 32 side.

[0028]Herein, as illustrated in FIG. 5, the restraint 37 is, for example, a cylindrical member made of the same member as the extrusion plate 42, and is fixed to the extrusion plate 42 by welding. Two or more restraints 37 are disposed on diagonal ends of the extrusion plate 42. The restraint 37 is disposed on the extrusion plate 42 outside a region where the cavity 40 is formed.

[0029]As will be described in detail later, when the casting mold 11 is closed, the extrusion plate 42 moves toward the movable insert 32 side. As a result, the restraint 37 collides with the movable insert 32 outside the region where the cavity 40 is formed, and in a contact state with the movable insert 32. The contact state between the restraint 37 and the movable insert 32 is maintained, and a movement of the extrusion plate 42 toward the movable insert 32 side is restricted.

[0030] As illustrated in FIG. 4, in the casting mold 11, the movable platen 16 is guided by the tie bar 18 (see FIG. 1) via a drive mechanism (not illustrated) and approaches a fixed platen 15 side. Then, as indicated by a dash-dotted line 28, the housing 31 of the movable mold 14 and the housing 21 of the fixed mold 13 are in close contact with each other, and the casting mold 11 is in a closed state.

[0031]At this time, in the depth direction (the front-rear direction on the paper surface) of the casting mold 11, for example, a protrusion shape is formed in the cavity surface 22A of the fixed insert 22. Meanwhile, a recessed shape is formed in a cavity surface 32A of the movable insert 32. A space between the above-described protrusion shape and recessed shape is used as the cavity 40.

[0032]In the lateral width direction (the left-right direction on the paper surface) of the casting mold 11, the slide core 34 advances toward a cavity 40 side via the drive mechanism 45. A dotted line 46 indicates the cavity surface 34A of the slide core 34. The cavity surface 34A of the slide core 34 faces the cavity surface 22A (see FIG. 1) of the fixed insert 22 and forms a space of the cavity 40 of an overhang 25A of the molded article 25 (see FIG. 4).

[0033]With this structure, when the casting mold 11 is closed, the fixed insert 22, the movable insert 32, and the slide core 34 form the cavity 40 inside the casting mold 11. Then, the above-described molten metal injected from the injection device 12 flows into the cavity 40 in a high-pressure state from the molten metal supply port 23 via the runner 24 of the injection device 12. A part of the above-described molten metal flows from an air vent 40A into an outside of the cavity 40, and an inside of the cavity 40 is filled with the above-described molten metal.

[0034]As illustrated in the figure, the extrusion mechanism 36 is disposed on a rear surface side of the movable insert 32 of the movable mold 14. The extrusion mechanism 36 mainly includes an extrusion plate 51, extrusion pins 52, and a drive mechanism 53.

[0035]The drive mechanism 53 is, for example, a slide hydraulic cylinder. The drive mechanism 53 is disposed on the rear surface side of the movable insert 32 and is fixedly disposed on the movable platen 16. A cylinder 53A of the drive mechanism 53 is in a coupled state with a rear side surface 51B of the extrusion plate 51. The drive mechanism 53 slides the extrusion plate 51 in the depth direction (the front-rear direction on the paper surface) of the casting mold 11. The extrusion plate 51 is movably disposed in a storage space (not illustrated) of the housing 31.

[0036]The extrusion pins 52 are disposed on a front side surface 51A of the extrusion plate 51. The extrusion pins 52 are inserted into the movable insert 32 via insertion passages 55 provided in the movable insert 32. As illustrated in FIG. 2, small holes 54 are formed in the cavity surface 32A of the movable insert 32, and the small holes 54 are substantially uniformly disposed in the cavity surface 32A. The insertion passage 55 is formed through the movable insert 32 in the depth direction (the front-rear direction on the paper surface). The small hole 54 is a tip opening of the insertion passage 55.

[0037]As will be described in detail later, when the molded article 25 is demolded from the movable insert 32, the drive mechanism 53 operates to extend the cylinder 53A. The extrusion plate 51 slides toward the movable insert 32 side in accordance with an operation of the above-described cylinder 53A. Then, the extrusion pin 52 protrudes from the small hole 54, and the molded article 25 is separated from the movable insert 32. When the casting mold 11 is closed, the drive mechanism 53 is stopped in a state in which the cylinder 53A is contracted, and the extrusion pin 52 is in a non- protruding state from the small hole 54.

[0038]As illustrated in FIG. 5, the slide core 34 includes, for example, a first slide core 34B located on a front side of the extrusion plate 42, and a second slide core 34C located on a rear side of the extrusion plate 42. The first slide core 34B and the second slide core 34C are coupled to each other by, for example, bolt fastening, and are used as an integral structure.

[0039]The first slide core 34B has the cavity surface 34A that forms the cavity 40. Small holes 61 are formed in the cavity surface 34A. Insertion passages 38 (see FIG. 6) are formed in the first slide core 34B to correspond to the small holes 61. The insertion passage 38 penetrates through the first slide core 34B in the thickness direction (the left-right direction on the paper surface). The small hole 61 is a tip opening of the insertion passage 38.

[0040]The second slide core 34C has a recess 62 that forms the storage space 41. The recess 62 is formed on a front side surface 34D side of the second slide core 34C. In a plan view of the second slide core 34C from a front side, the recess 62 has substantially the same shape as the extrusion plate 42. The front side surface 34D of the second slide core 34C abuts against the rear side surface 34E of the first slide core 34B around the recess 62. As a result, the storage space 41 is formed inside the slide core 34.

[0041]With this structure, the extrusion plate 42 is in a state of being stored in the storage space 41. Then, the slide core 34 moves in the advancing and retracting direction (the left-right direction on the paper surface) with respect to the movable insert 32 via the drive mechanism 45. The extrusion plate 42 is also movable together with the slide core 34. At this time, the extrusion pin 43 is inserted into the insertion passage 38 of the first slide core 34B. Then, the extrusion plate 42 slides while being guided by an inner surface of the recess 62.

[0042]As illustrated in FIG. 6, when the casting mold 11 is closed, the pressing mechanism 44 presses the extrusion plate 42 toward the movable insert 32 side. Then, the extrusion plate 42 slides toward the movable insert 32 side. The restraint 37 disposed on the extrusion plate 42 comes into contact with the movable insert 32 around the cavity 40.

[0043]With this structure, the extrusion plate 42 is continuously pressed by the pressing mechanism 44. Meanwhile, a slide movement of the extrusion plate 42 toward the movable insert 32 side is restricted due to the contact state between the restraint 37 and the movable insert 32. The extrusion plate 42 is located on a rear side of the storage space 41. The extrusion plate 42 is in a state of being in contact with the front side surface 34D of the recess 62 of the second slide core 34C. That is, a gap of AS is formed between the extrusion plate 42 and the rear side surface 34E of the first slide core 34B.

[0044]Similarly, the drive mechanism 45 presses the slide core 34 toward the movable insert 32 side. Then, the slide core 34 slides toward the movable insert 32 side. At this time, in the storage space 41 of the slide core 34, the front side surface 34D of the recess 62 of the second slide core 34C is in a state of being in contact with the extrusion plate 42.

[0045]With this structure, the slide core 34 is continuously pressed by the drive mechanism 45. Meanwhile, the second slide core 34C comes into contact with the extrusion plate 42 inside the storage space 41, thereby restricting the slide core 34 from sliding toward the movable insert 32 side. In other words, the extrusion plate 42 is in a state of being pressed by the pressing mechanism 44 and the drive mechanism 45 via the slide core 34. Then, the restraint 37 comes into contact with the movable insert 32, and movements of the extrusion plate 42 and the slide core 34 toward the movable insert 32 side are restricted. The movement restriction of the slide core 34 may be adjusted according to an expansion length of the cylinder 45A.

[0046]As illustrated in the figure, the extrusion plate 42 is restricted from sliding toward the movable insert 32 side, and the extrusion pin 43 is also restricted from moving toward the cavity 40 side. A tip surface of the extrusion pin 43 is maintained flush with the cavity surface 34A of the slide core 34. Alternatively, the tip surface of the extrusion pin 43 is in a state of being recessed further toward an insertion passage 38 relative to the cavity surface 34A. In other words, when the casting mold 11 is closed, the extrusion pin 43 is also fixed at a predetermined position due to the contact state between the restraint 37 and the movable insert 32.

[0047]As illustrated in FIG. 7, when the casting mold 11 is opened and when the overhang 25A of the molded article 25 is demolded (see FIG. 4), the pressing mechanism 44 continuously maintains the state of pressing the extrusion plate 42 toward the movable insert 32 side. The restraint 37 is in a state of being in contact with the movable insert 32 around the cavity 40. Meanwhile, the drive mechanism 45 performs a reverse movement from the state in which the slide core 34 is pressed toward the movable insert 32 side to contract the cylinder 45A. Then, the slide core 34 is retracted from the movable insert 32 side. The overhang 25A according to the present embodiment is a part of the molded article 25 formed using the cavity 40 between the fixed insert 22 and the slide core 34.

[0048]Herein, as described above with reference to FIG. 6, when the casting mold 11 is closed, the gap of AS is formed between the extrusion plate 42 and the rear side surface 34E of the first slide core 34B in the storage space 41 of the slide core 34. With this structure, immediately after the slide core 34 is retracted, the extrusion plate 42 is maintained by the restraint 37 and the pressing mechanism 44 in a state of being fixed in position. Meanwhile, the slide core 34 is retracted by the above-described AS.

[0049]With this structure, the extrusion plate 42 relatively moves toward a front side of the storage space 41 by the above-described AS. The extrusion pin 43 protrudes from the cavity surface 34A of the slide core 34 by the above-described AS. That is, a protrusion operation of the extrusion pin 43 from the cavity surface 34A is controlled by a retraction movement of the slide core 34 by the drive mechanism 45. The extrusion pin 43 starts to protrude from the cavity surface 34A substantially simultaneously with the retraction movement of the slide core 34.

[0050]As a result, the overhang 25A of the molded article 25 is pushed by the extrusion pin 43 in a direction opposite to a retraction direction of the slide core 34 and is separated from the cavity surface 34A. At this time, the slide core 34 is retracted to a predetermined position, and immediately after the slide core 34 is retracted, the slide core 34 is separated from the cavity surface 34A by the extrusion pin 43. The overhang 25A of the molded article 25 is prevented from being pulled more than necessary in the retraction direction of the slide core 34. The overhang 25A of the molded article 25 is prevented from deforming in the above-described opening direction. Product quality is improved. Furthermore, a demold process of the overhang 25A is interlocked with the retraction movement of the slide core 34, which simplifies an operation control thereof. Since a structure of the casting mold is simplified, manufacturing cost is reduced.

[0051]As illustrated in FIG. 8, after the slide core 34 is retracted by the above-described AS, the pressing mechanism 44 is stopped to eliminate a pressing force applied to the extrusion plate 42. In other words, after a predetermined time has elapsed from the above-described reverse movement of the drive mechanism 45, the pressing mechanism 44 is stopped, and the pressing force applied to the extrusion plate 42 is eliminated.

[0052]With this structure, the slide core 34 performs the retraction movement by the above-described AS, and the extrusion plate 42 is relatively located on the front side of the storage space 41. The extrusion plate 42 is in a state of being in contact with the front side surface 34D of the first slide core 34B. As a result, the extrusion plate 42 maintains the above-described contact state with the first slide core 34B. Thereafter, the extrusion plate 42 is pulled by the slide core 34, and is retracted together with the slide core 34. Then, the slide core 34 is retracted to the predetermined position, and the drive mechanism 45 is stopped.

[0053]Next, a method for casting the molded article 25 (see FIG. 4) according to another embodiment of the present disclosure will be described. In a description of the method for casting the molded article 25, reference is made to the descriptions of the casting apparatus 10, the casting mold 11, and the like described with reference to FIGS. 1 to 8 as appropriate. In principle, the same reference numerals are used for the same members, and repetitive description will be omitted.

[0054]The method for casting the molded article 25 according to the present embodiment mainly includes a process of setting the casting mold 11, a process of closing the casting mold 11 and molding the molded article 25, and a process of opening the casting mold 11 and demolding the molded article 25. Next, in the present embodiment, a case where the overhang 25A is formed on an outer peripheral edge of a main body 25B of the molded article 25 will be described. The main body 25B according to the present embodiment is a part of the molded article 25 formed by using the cavity 40 between the movable insert 32 and the fixed insert 22.

[0055] First, as illustrated in FIGS. 1 and 2, in the process of setting the casting mold 11, an operator prepares the fixed insert 22, the movable insert 32, and the slide core 34 according to a shape of the molded article 25. Then, the operator assembles the fixed insert 22 to the housing 21 of the fixed platen 15. Similarly, the operator assembles the movable insert 32 and the slide core 34 to the housing 31 of the movable platen 16.

[0056]At this time, as described above, the extrusion plate 42 disposed inside the slide core 34 has a non- coupling structure with the cylinder 44A of the extrusion hydraulic cylinder, which is the pressing mechanism 44. In one example, a cylinder receiver (not illustrated), for example, is formed on the rear surface side of the extrusion plate 42. An assembly operation of the slide core 34 is performed such that a tip of the cylinder 44A is inserted into the above-described cylinder receiver.

[0057]As a result, the operator does not perform a coupling operation and a detachment operation of the cylinder 44A and the extrusion plate 42 in the storage space 41 of the slide core 34. In one example, the storage space 41 is narrow, the above-described operation on the rear surface side of the extrusion plate 42 is omitted, and therefore, work efficiency is improved, and work time is shortened.

[0058]Next, as illustrated in FIGS. 3, 4, and 6, in the process of molding the molded article 25, a drive mechanism (not illustrated), such as a motor, operates, and the movable platen 16 slides toward the fixed platen 15 side while being guided by the tie bars 18 in the casting apparatus 10. Then, in the casting apparatus 10, the movable insert 32 of the movable mold 14 and the fixed insert 22 of the fixed mold 13 are in close contact with each other, and the casting mold 11 is in a closed state.

[0059]At this time, as described above, in the movable mold 14, the pressing mechanism 44 and the drive mechanism 45 are operated, and the slide core 34 and the extrusion plate 42 are fixed to predetermined positions. Then, the cavity 40 is formed in the casting mold 11 by the fixed insert 22, the movable insert 32, and the slide core 34.

[0060]Thereafter, in the injection device 12 of the casting apparatus 10, an alloy of a non-ferrous metal such as aluminum, zinc, and magnesium is melted. Thereafter, in the injection device 12, the molten metal flows into the cavity 40 at a high pressure from the molten metal supply port 23 via the runner 24. Then, in the casting mold 11, the molten metal filled in the cavity 40 is cooled and solidified, thereby molding the molded article 25 in the cavity 40.

[0061]Next, in the process of demolding the molded article 25 from the casting mold 11, a drive mechanism (not illustrated) operates to retract the movable platen 16 from the fixed platen 15 while being guided by the tie bars 18. Then, as the movable platen 16 slides, the movable insert 32 of the movable mold 14 is separated from the fixed insert 22 of the fixed mold 13, and the casting mold 11 is in an open state.

[0062]First, at an initial stage of the above-described mold opening, the movable insert 32 is separated from the fixed insert 22. Then, the inner surface of the overhang 25A of the molded article 25 is detached from the fixed insert 22. Meanwhile, the whole outer surface of the molded article 25 is in a state of being in close contact with the movable insert 32 and the slide core 34. Further, the slide core 34 is also in a state of being pressed toward the movable insert 32 side, and the molded article 25 and the extrusion mechanism 35 are also retracted together with the movable insert 32. Thereafter, the movable platen 16 is retracted to a predetermined position when the casting mold 11 is opened.

[0063]Next, in the casting apparatus 10, the extrusion mechanisms 35 disposed on both sides of the movable insert 32 of the movable mold 14 are operated. Then, the overhang 25A of the molded article 25 is detached from the slide core 34. As described above with reference to FIGS. 7 and 8, in a state in which the pressing mechanism 44 is operated, the slide core 34 is retracted by using the drive mechanism 45.

[0064]With this demold method, the extrusion pin 43 protrudes from the cavity surface 34A substantially simultaneously with the retraction movement of the slide core 34. Then, in the overhang 25A of the molded article 25, the slide core 34 is retracted after being pressed toward the movable insert 32 side by the extrusion pin 43. That is, the overhang 25A of the molded article 25 is detached from the cavity surface 34A of the slide core 34 by being pushed by the extrusion pin 43. After the overhang 25A of the molded article 25 is detached from the cavity surface 34A, the slide core 34 is retracted to a predetermined position when the casting mold 11 is opened.

[0065]Next, in the casting apparatus 10, the extrusion mechanism 36 disposed on the rear surface side of the movable insert 32 of the movable mold 14 operates to separate the main body 25B of the molded article 25 from the movable insert 32. As described above with reference to FIG. 4, the drive mechanism 53 is driven to press the extrusion plate 51 toward the cavity 40 side, and the extrusion pin 52 protrudes from the cavity surface 32A of the movable insert 32 via the small hole 54. Then, the main body 25B of the molded article 25 is pushed by the extrusion pin 52 and is detached from the movable insert 32, and the molded article 25 is completely demolded from the movable insert 32.

[0066]In the method for casting the molded article 25 according to the present embodiment, first, the molded article 25 is detached from the fixed insert 22 in a state in which the overhang 25A of the molded article 25 is pressed by the slide core 34. Next, the extrusion mechanism 35 of the movable mold 14 operates to separate the overhang 25A of the molded article 25 from the slide core 34 by using the extrusion pin 43. Finally, the extrusion mechanism 36 of the movable mold 14 operates to separate the main body 25B of the molded article 25 from the movable insert 32. With the demolding method of the molded article 25, the overhang 25A of the molded article 25 is pushed by the extrusion pin 43 in a direction opposite to a retraction direction of the slide core 34 and is separated from the cavity surface 34A. As a result, the overhang 25A of the molded article 25 is prevented from being pulled more than necessary in the retraction direction of the slide core 34. The overhang 25A of the molded article 25 is prevented from deforming in the opening direction. The molded article 25 having excellent product quality is manufactured, the yield of the molded article 25 is improved, and the manufacturing cost is reduced.

[0067]In the extrusion mechanism 35, the pressing mechanism 44 has a function of pressing the extrusion plate 42. In the demold process of the overhang 25A of the molded article 25, in conjunction with the retraction movement of the slide core 34, a control operation when the overhang 25A is detached from the cavity surface 34A is simplified. As a result, the structure of the casting mold 11 is simplified, the number of components is reduced, the mold cost is reduced, and the manufacturing cost is reduced.

[0068]In the present embodiment, the case in which the cylinder 44A of the pressing mechanism 44 and the extrusion plate 42 are in a non-coupling structure has been described. The present disclosure is not limited to this case. For example, the cylinder 44A and the extrusion plate 42 may be mechanically coupled to each other by bolt fastening or the like. Even in this case, as described above, the pressing mechanism 44 stops at a predetermined timing, and the extrusion plate 42 is retracted by using the drive mechanism 45 and the slide core 34. Various other modifications may be made without departing from the gist of the present disclosure.

[0069]In the casting mold according to the embodiment of the present disclosure, when the casting mold is closed, the extrusion plate is pressed toward the movable insert side by the pressing mechanism. Then, when the molded article is demolded from the casting mold, the extrusion plate is maintained in the above-described pressed state, the slide core is retracted by the drive mechanism, and the overhang of the molded article is separated from the cavity surface of the slide core by using the extrusion pin. With this structure, the overhang of the molded article is not likely to deform when demolding from the casting mold. The structure of the casting mold is simplified, and the manufacturing cost is reduced.

[0070]In the method for casting a molded article according to the embodiment of the present disclosure, in the process of demolding the molded article from the casting mold, the overhang of the molded article is detached from the fixed insert in a state of being in close contact with the slide core. Next, the slide core is retracted, and in a state in which the main body of the molded article is in close contact with the movable insert, the above-described overhang is detached from the cavity surface of the slide core by using the extrusion pin. Finally, the main body of the molded article is detached from the movable insert. By the demold process of the molded article, the molded article is gradually demolded from the casting mold, and the overhang of the molded article is less likely to deform. The product quality of the molded article is improved.

[0071]An aspect of the present disclosure provides a casting mold including a fixed mold and a movable mold, in which a cavity that is formed when the fixed mold and the movable mold are closed is filled with a molten mold material to mold a molded article having a desired shape. The casting mold includes: a fixed insert disposed in the fixed mold that defines the cavity, a movable insert disposed in the movable mold, and a slide core disposed in the movable mold; an extrusion pin disposed in the slide core; an extrusion plate coupled to the extrusion pin and disposed movably with respect to the slide core; a pressing mechanism configured to press the extrusion plate toward a movable insert side; and a drive mechanism configured to slide the slide core. A storage space configured to allow the extrusion plate to be movably stored is provided inside the slide core. The slide core, the extrusion plate and the extrusion pin are configured such that, in a state in which the extrusion plate is pressed by the pressing mechanism, the slide core is retracted from the movable insert side by the drive mechanism, the extrusion plate moves within the storage space, and the extrusion pin protrudes from a cavity surface of the slide core.

[0072] An aspect of the present disclosure provides a method for casting a molded article to mold a molded article having a desired shape by using a casting mold that includes: a fixed mold including at least a fixed insert; and a movable mold including a slide core, a movable insert, an extrusion plate, an extrusion pin, and a restraint. The method includes: bringing the restraint disposed on the extrusion plate into contact with the movable insert in a state in which the extrusion plate is pressed toward a movable insert side, and closing the casting mold in a state in which the extrusion plate and the extrusion pin are fixed in position; filling a cavity formed by the fixed insert, the movable insert, and the slide core with a molten mold material, and cooling and solidifying the mold material to mold the molded article; and opening the casting mold and demolding the molded article from the cavity. In the demolding the molded article, the extrusion pin protrudes from a cavity surface of the slide core in conjunction with a retraction movement of the slide core, and after an overhang of the molded article is separated from the cavity surface, the slide core is used to retract the extrusion plate from the movable insert side.

[0073]A mold apparatus described in Japanese Unexamined Patent Application Publication (JP-A) No. 2004-188470 includes a fixed main mold, a movable main mold, an injection device, an extruder, and a nested pin. When the mold apparatus is closed, a fixed insert of the fixed main mold and a movable insert of the movable main mold form a cavity. Then, a molten metal material is poured into the above-described cavity from the injection device to mold a die-cast molded article having a desired shape.

[0074]The extruder includes an extrusion plate and an extrusion pin fixed to the extrusion plate. The extruder is used to separate the die-cast molded article from the above-described movable insert. The extrusion plate slides between an end surface of the movable main mold and a fixing plate that slidably fixes the movable main mold.

[0075]When the mold apparatus is opened, the movable insert retracts together with the movable main mold from the fixed insert, and the die-cast molded article is detached from the fixed insert in a state of being in close contact with the movable insert. Thereafter, the extrusion plate slides toward a movable insert side, and the nested pin protrudes from a cavity surface of the movable insert. Thereafter, the die-cast molded article is detached from the movable insert.

[0076]Herein, the above-described die-cast molded article includes a funnel-shaped circular part, an overhang formed on an outer peripheral edge of the circular part, and a boss formed at a center of the circular part. When the die-cast molded article is detached from the movable insert, the die-cast molded article is demolded along the nested pin in the funnel-shaped circular part of the die- cast molded article. As a result, a shape of an inner surface of the boss of the die-cast molded article is adjusted.

[0077]As described above, in a demold process of the die- cast molded article, the nested pin is used to prevent deformation of the boss of the die-cast molded article. The nested pin is made of, for example, carbon steel subjected to quenching processing or the like. The nested pin is formed by combining tapered shapes. As a result, a casting mold requires nested pins in a structure in the related art, which results in an increase in manufacturing cost of the casting mold.

[0078]Depending on shapes of the die-cast molded article, at a time of demold from the casting mold, the overhang of the die-cast molded article may be added with pulling forces in various directions, causing the above-described overhang to deform from the desired shape. Therefore, when demolding the die-cast molded article from the movable insert, it is desirable to devise measures to prevent deformation of the above-described overhang.

[0079]The present disclosure relates to a casting mold and a method for casting a molded article by demolding the molded article stepwise from the casting mold to prevent deformation of the molded article.

[0080]Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.