Mold structure and method for manufacturing the mold structure

Abstract

To provide a metal-mold structure for die casting allowed to suppress a squeeze pin from malfunctioning due to a thermal expansion at or around the squeeze pin to pressurize a melt.SOLUTION: A metal-mold structure for die casting comprises a wall part that is formed with a penetration hole communicating with a cavity, a shaft-like pressurizing pin that is slidably arranged in the penetration hole along an inner wall of the penetration hole and for pressurizing a melt within the cavity, and a cooling part that is provided in the wall part and for cooling down the pressurizing pin.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a mold structure and a method for manufacturing the mold structure. [Background technology]

[0002] In die casting, a technique is known in which the molten metal in the cavity of a mold is locally pressurized by a squeeze pin inserted into a through hole communicating with the cavity (for example, Patent Document 1). This technique can suppress the formation of blowholes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-23821 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, heat transfer from the cavity may cause the squeeze pin to thermally expand, or the mold may thermally expand so as to narrow the through hole. Such thermal expansion may hinder the operation of the squeeze pin. [Means for solving the problem]

[0005] The present invention can be realized as the following aspects. According to one aspect of the present disclosure, there is provided a die structure for die casting. The die structure includes a wall portion having a through hole communicating with a cavity, a shaft-shaped pressure pin slidably disposed along the inner wall surface of the through hole and pressurizing the molten metal in the cavity, and a cooling portion disposed in the wall portion for cooling the pressure pin. The cooling portion has a cooling passage within the wall portion through which a cooling medium flows to cool the pressure pin. The cooling passage includes a first partial passage extending in a direction perpendicular to the through-hole direction and having a first end and a second end, where the distance from the first end to the pressure pin is shorter than the distance from the second end to the pressure pin, and a second partial passage connected to the second end and extending along the through-hole direction. A pair of the first partial passages is disposed such that the pressure pin is disposed between the pair of first partial passages in the perpendicular direction. The pair of second partial flow paths are provided such that the pressure pin is disposed between the pair of second partial flow paths in the orthogonal direction. The cooling flow path further includes a third partial flow path connecting the first ends of the pair of first partial flow paths so as to surround the periphery of the pressure pin. According to one aspect of the present disclosure, there is provided a method for manufacturing a die structure for die casting. The method for manufacturing the die structure includes: a first step of forming a wall portion having a through hole in which a shaft-shaped pressure pin for pressurizing a molten metal in a cavity is disposed; and a cooling channel through which a coolant for cooling the pressure pin flows; and a second step of inserting the pressure pin into the through hole so that the wall portion is slidable along the inner wall surface of the through hole. In the first step, the cooling channel is formed by forming a portion of the wall portion that defines the cooling channel by additive manufacturing. The cooling channel formed in the first step includes a first partial channel extending in a direction perpendicular to the through hole extension direction and having a first end and a second end, where the distance from the first end to the pressure pin is shorter than the distance from the second end to the pressure pin, and a second partial channel connected to the second end and extending along the through hole direction. A pair of the first partial flow paths are provided such that the pressure pin is disposed between the pair of first partial flow paths in the orthogonal direction. A pair of second partial flow paths are provided such that the pressure pin is disposed between the pair of second partial flow paths in the orthogonal direction. The cooling flow path formed in the first step further includes a third partial flow path that is circular when viewed along the penetration direction and connects the first ends of the pair of first partial flow paths so as to surround the periphery of the pressure pin.

[0006] (1) According to a first aspect of the present disclosure, there is provided a die structure for die casting, the die structure comprising: a wall portion having a through hole communicating with a cavity, a shaft-shaped pressure pin slidably disposed along the inner wall surface of the through hole to apply pressure to molten metal in the cavity, and a cooling portion provided on the wall portion to cool the pressure pin. In this configuration, the pressure pin can be cooled by the cooling portion provided in the wall portion, so that it is possible to prevent the sliding of the pressure pin from being hindered by thermal expansion of the pressure pin or the wall portion. (2) In the above aspect, the cooling unit may have a cooling flow path within the wall portion through which a cooling medium for cooling the pressure pin flows. In this aspect, the pressure pin can be easily cooled by flowing the cooling medium through the cooling flow path within the wall portion. (3) In the above embodiment, the cooling flow path may include a first partial flow path extending in a direction intersecting the through-hole extension direction and having a first end and a second end, wherein the distance from the first end to the pressure pin is shorter than the distance from the second end to the pressure pin, and a second partial flow path connected to the second end and extending in the through-hole extension direction. With this embodiment, the cooling flow path can be disposed near the pressure pin while preventing the length of the portion of the cooling flow path that extends intersecting the through-hole extension direction from increasing. (4) In the above-described embodiment, at least a portion of the cooling unit may be disposed so as to surround the periphery of the pressure pin. In this embodiment, the pressure pin can be more effectively cooled by the cooling unit. (5) According to a second aspect of the present disclosure, there is provided a method for manufacturing a die structure for die casting. This method for manufacturing a die structure includes a first step of forming a wall portion having a through hole in which a shaft-shaped pressure pin that pressurizes molten metal in a cavity is disposed and a cooling passage through which a cooling medium that cools the pressure pin flows, and a second step of inserting the pressure pin into the through hole so that the pressure pin is slidable along the inner wall surface of the through hole. In the first step, the cooling passage is formed by forming a portion of the wall portion that defines the cooling passage by additive manufacturing.

[0007] The present disclosure can be realized in various forms, such as a die-casting apparatus having a die structure, in addition to the above-described die structure and method for manufacturing the die structure. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a diagram showing a schematic configuration of a die-casting device. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a pressure mechanism in the first embodiment. [Figure 3] 10 is a flowchart illustrating a method for manufacturing a mold structure. [Figure 4] FIG. 10 is a diagram showing a schematic configuration of a pressure mechanism in a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. First embodiment: 1 is a diagram showing a schematic configuration of a die-casting apparatus 100 according to this embodiment. The die-casting apparatus 100 includes a mold structure 20, an injection unit 110, and a control unit 150. Under the control of the control unit 150, the die-casting apparatus 100 injects molten metal from the injection unit 110 into a cavity Cv in the mold structure 20, thereby casting a die-cast product in the cavity Cv.

[0010] The control unit 150 controls each part of the die-casting apparatus 100. In this embodiment, the control unit 150 is configured as a computer equipped with a CPU and memory, and casts a die-cast product by executing a program for controlling each part of the die-casting apparatus 100. The control unit 150 may be configured, for example, by a programmable logic controller (PLC).

[0011] The injection unit 110 has an injection plunger 111 and an injection cylinder 112. The injection cylinder 112 is in communication with the cavity Cv via a molten metal flow path 114 having a gate. Molten metal is supplied into the injection cylinder 112 from the outside via a supply port 113 formed in the injection cylinder 112. The injection plunger 111 is slidably disposed within the injection cylinder 112. Under the control of the control unit 150, the injection plunger 111 is driven by a drive unit (not shown) constituted by, for example, a motor, and moves forward within the injection cylinder 112 in a direction approaching the cavity Cv, thereby injecting the molten metal in the injection cylinder 112 into the cavity Cv.

[0012] The mold structure 20 is configured as a mold structure for die casting and has a main body 30 and a pressurizing mechanism 50. The main body 30 has a fixed mold 31 and a movable mold 40. A cavity Cv is defined by the fixed mold 31 and the movable mold 40. Ejector pins (not shown) for removing the die-cast product from the cavity Cv are appropriately arranged in the fixed mold 31 and the movable mold 40. The movable mold 40 moves relative to the fixed mold 31 by the operation of a mold clamping device (not shown), such as a toggle type or direct pressure type. This causes the fixed mold 31 and the movable mold 40 to open, close, and clamp. The operation of the mold clamping device is controlled by a control unit 150. Hereinafter, the direction of movement of the movable mold 40 during mold clamping will also be referred to as the mold clamping direction.

[0013] The fixed mold 31 in this embodiment is configured as a nested mold and has a main mold 32 and a nested mold 33 attached to the main mold 32. In this embodiment, the nested mold 33 has a further nested structure and has a first nested mold 34 and a second nested mold 35 attached to the first nested mold 34. The second nested mold 35 in this embodiment defines the cavity Cv and forms a first wall portion 55 and a second wall portion 56, which will be described later. Note that in other embodiments, for example, the nested mold 33 may not have a nested structure. Furthermore, the fixed mold 31 may not be configured as a nested mold. Similarly, the movable mold 40 may or may not be configured as a nested mold.

[0014] FIG. 2 is a diagram showing a schematic configuration of the pressure mechanism 50 in this embodiment. FIG. 2 shows the vicinity of the pressure mechanism 50 in the nested mold 33. As shown in FIGS. 1 and 2, in this embodiment, the pressure mechanism 50 is incorporated into the fixed mold 31. As shown in FIG. 2, the pressure mechanism 50 has a first wall 55, a pressure unit 60 having a pressure pin 61 and a cylinder 65, and a cooling unit 80. The pressure mechanism 50 in this embodiment further has a second wall 56. Note that in other embodiments, the pressure mechanism 50 may be incorporated into, for example, the movable mold 40.

[0015] The first wall portion 55 refers to a portion of the mold structure 20 in which a through hole 57 communicating with the cavity Cv is formed. As described above, the first wall portion 55 in this embodiment is formed by the second insert 35. A shaft-shaped pressure pin 61 is arranged in the through hole 57, as will be described later. Furthermore, a cooling unit 80 is provided in the first wall portion 55, as will be described later. In other embodiments, the first wall portion 55 may be formed by any portion constituting the fixed mold 31 or the movable mold 40 as long as it has the through hole 57. For example, the first wall portion 55 may be formed by a portion of the fixed mold 31 or the movable mold 40 that does not define the cavity Cv. In this case, a portion of the mold structure 20 that defines the cavity Cv is located between the first wall portion 55 and the cavity Cv. Hereinafter, the direction in which the through hole 57 extends will also be referred to as the penetration direction d1. The penetration direction d1 includes both the direction on one side and the direction on the opposite side. The penetration direction d1 in this embodiment is the direction along the mold clamping direction described above. In the following, the first wall portion 55 will also be simply referred to as the wall portion.

[0016] The second wall portion 56 is configured as a wall that partitions an arrangement chamber 69 formed in the second nesting member 35. The arrangement chamber 69 is arranged on the opposite side of the first wall portion 55 from the cavity Cv in the second nesting member 35. The arrangement chamber 69 communicates with the cavity Cv via a through-hole 57.

[0017] In this embodiment, the through hole 57 is formed by a first hole portion 58 that is closer to the cavity Cv and a second hole portion 59 that is farther from the cavity Cv, which are connected in the through-hole direction d1. The first hole portion 58 and the second hole portion 59 each have a substantially circular opening shape when viewed along the through-hole direction d1. The opening diameter of the first hole portion 58 is smaller than the opening diameter of the second hole portion 59.

[0018] The pressure pin 61 has a shaft shape and is disposed in the through hole 57 so that its axis AX is aligned with the through-hole direction d1 and is slidable along the inner wall surface of the through hole 57. The pressure pin 61 is also referred to as a squeeze pin. More specifically, the pressure pin 61 in this embodiment has a first portion P1 having one end 62 of the pressure pin 61 that is close to the cavity Cv, and a second portion P2 having the other end 63 of the pressure pin 61 that is far from the cavity Cv. The second portion P2 has a larger cross-sectional diameter than the first portion P1 and is disposed in the second hole portion 59. The first portion P1 is disposed in a substantially cylindrical bushing (not shown) disposed in the first hole portion 58 along the through-hole direction d1. This bushing is also referred to as a squeeze bushing. The gap between the inner surface of the squeeze bushing and the outer surface of the first portion P1 is set small enough, for example, to prevent the molten metal in the cavity Cv from flowing into the placement chamber 69 through this gap. The pressure pin 61 is arranged so that it can slide along the penetration direction d1 and advance toward the cavity Cv, thereby protruding one end 62 into the cavity Cv. The pressure pin 61 locally pressurizes the molten metal in the cavity Cv by advancing in this manner so that the one end 62 protrudes into the cavity Cv. This localized pressurization of the molten metal in the cavity Cv by the pressure pin 61 is also referred to as local pressurization.

[0019] In this embodiment, a part of the cylinder 65 is disposed within the arrangement chamber 69. The cylinder 65 is configured as a hydraulic cylinder, and the pressure pin 61 connected to the cylinder 65 is moved along the through-hole direction d1 by changing the hydraulic pressure within the cylinder 65 under the control of the control unit 150. This causes the pressure pin 61 to slide within the through-hole 57 along the through-hole direction d1. In this embodiment, the cylinder 65 has a cylindrical shape with an outer diameter larger than that of the pressure pin 61, and is connected to the other end 63 of the pressure pin 61, which is the end farther from the cavity Cv. Note that in other embodiments, the cylinder 65 may be configured as, for example, an air cylinder driven by air or an electric cylinder driven by a motor.

[0020] The cooling unit 80 is provided in the first wall portion 55 and cools the pressure pin 61. In this embodiment, the cooling unit 80 has a first refrigerant flow path 71 inside the first wall portion 55, through which a cooling medium flows to cool the pressure pin 61. The cooling unit 80 cools the pressure pin 61 by removing heat from the pressure pin 61 through heat exchange between the cooling medium flowing inside the first refrigerant flow path 71 and the pressure pin 61. In this embodiment, the first refrigerant flow path 71 is configured as part of a flow path 88 provided in the second insert 35. The flow path 88 has the first refrigerant flow path 71 and a second refrigerant flow path 89 arranged inside the second wall portion 56. The second refrigerant flow path 89 is connected to the first refrigerant flow path 71. In this embodiment, cooling water is used as the cooling medium. A supply unit 79 that supplies the cooling medium to the first refrigerant flow path 71 is connected to the first refrigerant flow path 71. The supply unit 79 is configured as, for example, a chiller that cools the cooling water and circulates the cooling water within the first refrigerant flow path 71 under the control of the control unit 150. In this embodiment, the supply unit 79 is connected to the first refrigerant flow path 71 via a second refrigerant flow path 89. Note that in other embodiments, the cooling medium may be, for example, oil or a gas such as air or nitrogen. Hereinafter, the first refrigerant flow path 71 will also be referred to as a cooling flow path.

[0021] In this embodiment, the first refrigerant flow path 71 includes a first partial flow path 72 and a second partial flow path 73 within the first wall portion 55. The first partial flow path 72 extends in a direction intersecting the through-hole direction d1. The first partial flow path 72 has a first end 76 and a second end 77. The distance from the first end 76 to the pressure pin 61 is shorter than the distance from the second end 77 to the pressure pin 61. In this embodiment, the first partial flow path 72 extends in an orthogonal direction d2 that is orthogonal to the through-hole direction d1. The orthogonal direction d2 includes both the direction on one side and the direction on the opposite side. That is, in this embodiment, the first partial flow path 72 extends in the orthogonal direction d2 from the first end 76 to the second end 77, moving away from the pressure pin 61. The second partial flow path 73 is connected to the second end 77 and extends in the through-hole direction d1.

[0022] More specifically, in this embodiment, the first refrigerant flow path 71 includes a pair of first partial flow paths 72 and a pair of second partial flow paths 73. A first end 76 of each first partial flow path 72 is disposed between the cylinder 65 and the cavity Cv. A second end 77 of each first partial flow path 72 is disposed outside the cylinder 65 when viewed along the through-direction d1. Each second partial flow path 73 extends from the second end 77 along the through-direction d1 in a direction away from the cavity Cv. A second refrigerant flow path 89 is connected to each second partial flow path 73. In this embodiment, the second refrigerant flow path 89 extends outside the side surface of the cylinder 65 along the through-direction d1 to a surface PL of the second insert 35 that is farther from the cavity Cv. That is, in the present embodiment, the flow paths 88 extend from the surface PL toward the cavity Cv along the penetrating direction d1 so as to avoid the cylinder 65, then bend at the second end 77 and extend to a position between the cylinder 65 and the cavity Cv. A supply unit 79 is connected to an end of each second refrigerant flow path 89 on the surface PL side. Note that, for example, a baffle plate for controlling the flow of the cooling medium within the flow path 88 may be disposed within the flow path 88. Also, for example, as described above, in other embodiments, when the first wall portion 55 is formed by a portion that does not define the cavity Cv, the first partial flow path 72 may be disposed within the first wall portion 55 so as to extend toward the cavity Cv along the penetrating direction d1.

[0023] 3 is a flowchart showing a manufacturing method of the mold structure 20 in this embodiment. As shown in FIG. 3, the manufacturing method of the mold structure 20 has a first step and a second step. The first step refers to a step of forming a first wall portion 55 having a through hole 57 and a first refrigerant flow path 71. The second step refers to a step of inserting a pressure pin 61 into the through hole 57 so that the pressure pin 61 is slidable along the inner wall surface of the through hole 57. In the first step, the first refrigerant flow path 71 is formed by forming a portion of the first wall portion 55 that defines the first refrigerant flow path 71 by additive manufacturing. The step of forming the first refrigerant flow path 71 by additive manufacturing in this manner is also referred to as an additive manufacturing step.

[0024] In the first process of this embodiment, first, in step S110, the above-described additive manufacturing process is performed. In the additive manufacturing process of this embodiment, a shaped object corresponding to a portion of the second nesting member 35 that defines the flow path 88 is formed, thereby forming the flow path 88 to be placed in the second nesting member 35. Hereinafter, the shaped object formed by additive manufacturing in step S110 will also be referred to as a first workpiece. The first workpiece in this embodiment is a workpiece before being machined into the second nesting member 35, and has a flow path 88 including the first refrigerant flow path 71, but does not have a through-hole 57 or an arrangement chamber 69. In other words, the first workpiece in this embodiment is a shaped object corresponding to the first wall portion 55 and the second wall portion 56.

[0025] In this embodiment, a powder bed method is used as the additive manufacturing method. More specifically, in step S110, metal powder is first spread in layers to form a metal powder layer. Next, light rays such as a laser or electron beam are irradiated onto portions of the metal powder layer that correspond to the solid portions of the first wall portion 55 and the second wall portion 56, while light rays are not irradiated onto portions of the first wall portion 55 and the second wall portion 56 that correspond to the flow paths 88. As a result, the portions that correspond to the solid portions are sintered and solidified, while the portions that correspond to the flow paths 88 are not sintered and remain powdery. Then, the formation of the metal powder layer and the irradiation of the light rays are repeated. Thereafter, the remaining powdery portions are removed to form a first workpiece having the flow paths 88. In other embodiments, for example, directed energy deposition, fused deposition modeling, or binder jetting may be used as the additive manufacturing method.

[0026] Next, in step S120, the through hole 57 and the placement chamber 69 are formed in the first workpiece. The through hole 57 and the placement chamber 69 may be formed using a cutting tool such as a drill or a mill, or may be formed by a laser or by electric discharge. Furthermore, for example, after the through hole 57 and the placement chamber 69 are formed, the inner surfaces of the through hole 57 and the placement chamber 69 may be ground.

[0027] In other embodiments, for example, only the first refrigerant flow path 71 of the flow path 88 may be formed by additive manufacturing. In this case, in the additive manufacturing process, a shaped object having only the first refrigerant flow path 71 of the flow path 88 is formed as the first workpiece. That is, the first workpiece may be a shaped object corresponding to only the first wall portion 55. In this case, for example, a first workpiece having the first refrigerant flow path 71 may be formed by additive manufacturing on a metal material to be processed into the second wall portion 56, and then the metal material may be machined using a cutting tool, a laser, or electric discharge to form the second refrigerant flow path 89. In other embodiments, some or all of the through hole 57 and the placement chamber 69 may be formed by additive manufacturing. For example, in step S110, the first wall portion 55 and the second wall portion 56 may be formed by additive manufacturing so that the through hole 57 and the first refrigerant flow path 71 are formed in the first wall portion 55 and the placement chamber 69 are formed in the second wall portion 56. In this case, step S120 may be omitted.

[0028] In step S130, the second step is executed. In the second step in this embodiment, first, the squeeze bushing described above is fixed in the first hole portion 58. Then, the cylinder 65 with the pressure pin 61 connected thereto is placed in the placement chamber 69, and the pressure pin 61 is inserted into the through hole 57 so as to be slidable along the inner wall surface of the through hole 57. More specifically, in step S130, the pressure pin 61 is inserted into the through hole 57 so that the second portion P2 is placed in the second hole portion 59 and the first portion P1 is placed in the squeeze bushing. In other embodiments, the cylinder 65 may be connected to the pressure pin 61 after, for example, the pressure pin 61 is inserted into the through hole 57. Furthermore, after step S130, or prior to step S130 or step S120, the supply unit 79 is connected to the first refrigerant flow path 71 via the second refrigerant flow path 89. Furthermore, the main mold 32, the first insert 34, and the movable mold 40 in this embodiment may be prepared by any method.

[0029] The mold structure 20 in this embodiment described above includes the cooling section 80 provided in the first wall section 55 to cool the pressure pin 61. Therefore, the pressure pin 61 can be cooled by the cooling section 80 provided in the first wall section 55, and therefore, compared to a configuration in which the cooling section 80 is not provided in the first wall section 55, it is possible to prevent the sliding of the pressure pin 61 from being hindered by thermal expansion of the pressure pin 61 or the first wall section 55.

[0030] In the present embodiment, the cooling unit 80 has a first refrigerant flow path 71, through which a cooling medium flows, inside the first wall portion 55. Therefore, by flowing the cooling medium through the first refrigerant flow path 71 inside the first wall portion 55, the pressure pin 61 and the first wall portion 55 can be easily cooled.

[0031] In this embodiment, the first refrigerant flow path 71 includes a first partial flow path 72 extending in a direction intersecting the through-hole direction d1 and a second partial flow path 73 connected to a second end 77 of the first partial flow path 72 and extending in the through-hole direction d1. This prevents the length of the portion of the first refrigerant flow path 71 extending in the first wall portion 55 intersecting the through-hole direction d1 from increasing, compared to, for example, a case in which the first refrigerant flow path 71 is configured only with a flow path intersecting the through-hole direction d1 and extending away from the pressurizing pin 61. This prevents interference between the first refrigerant flow path 71 and an ejection pin or injection cylinder 112, which are generally arranged along the through-hole direction d1. Furthermore, compared to a case in which the first refrigerant flow path 71 is configured only with the second partial flow path 73, the first refrigerant flow path 71 can be positioned closer to the pressurizing pin 61.

[0032] Furthermore, in this embodiment, the first refrigerant flow path 71 is formed by additive manufacturing. Therefore, the first refrigerant flow path 71 can be easily formed inside the first wall portion 55. In particular, even when the first refrigerant flow path 71 is bent midway, as in this embodiment, the first refrigerant flow path 71 can be easily formed. Furthermore, in other embodiments, even when a first refrigerant flow path 71 having a more complex shape, such as a first refrigerant flow path 71 that bends two or more times or a curved first refrigerant flow path 71, is disposed inside the first wall portion 55, the first refrigerant flow path 71 can be easily formed.

[0033] B. Second embodiment: Fig. 4 is a diagram showing a schematic configuration of a pressure mechanism 50b in the second embodiment. Like Fig. 2, Fig. 4 shows the appearance of the pressure mechanism 50b and its vicinity in the nested mold 33b. Unlike the first embodiment, in the second embodiment, at least a part of the cooling section 80b is arranged so as to surround the periphery of the pressure pin 61. Portions of the configuration of the die structure 20b and the die-casting apparatus 100 in the second embodiment that are not particularly described are the same as those in the first embodiment.

[0034] In the present embodiment, the first wall portion 55b is also formed by the second nest 35b. The first refrigerant flow path 71b formed in the first wall portion 55b has a third partial flow path 75. In the present embodiment, the third partial flow path 75 is formed in a substantially circular shape as a whole when viewed along the through-hole direction d1, and connects the first ends 76 of the first partial flow paths 72 so as to surround the periphery of the pressurizing pin 61. As a result, at least a portion of the cooling unit 80b is disposed so as to surround the periphery of the pressurizing pin 61. Furthermore, in the present embodiment, one supply unit 79 is connected to two second refrigerant flow paths 89. As a result, in the flow path 88b in the present embodiment, one second refrigerant flow path 89 functions as an inlet that introduces a cooling medium into the first refrigerant flow path 71, and the other second refrigerant flow path 89 functions as a recovery unit that recovers the cooling medium from the first refrigerant flow path 71.

[0035] In other embodiments, the third partial flow passages 75 may be formed, for example, in a generally polygonal shape as a whole when viewed along the penetration direction d1. Furthermore, when it is stated that "at least a portion of the cooling section 80b is arranged so as to surround the periphery of the pressure pin 61," it is sufficient that at least a portion of the cooling section 80b is arranged so as to surround the periphery of the pressure pin 61 as a whole, and it is not necessary for the cooling section 80b to completely surround the periphery of the pressure pin 61. For example, a plurality of generally arc-shaped third partial flow passages 75 or a plurality of linear third partial flow passages 75 may be arranged so as to surround the periphery of the pressure pin 61.

[0036] According to the mold structure 20b in the second embodiment described above, the cooling section 80b is disposed so as to surround the periphery of the pressure pin 61. Therefore, the pressure pin 61 can be cooled more effectively by the cooling section 80b.

[0037] Furthermore, by manufacturing the mold structure 20b in this embodiment using additive manufacturing in the same way as in the first embodiment, it is possible to easily form the flow path that constitutes the portion of the cooling section 80 that is arranged to surround the periphery of the pressure pin 61. More specifically, by using additive manufacturing, it is possible to more easily form the bent or curved portion of the flow path that is arranged to surround the periphery of the pressure pin 61, compared to when, for example, discharge is used.

[0038] C. Other Embodiments: (C1) In the above embodiment, the first refrigerant flow path 71 has the first partial flow path 72 and the second partial flow path 73, but it does not have to have the first partial flow path 72 or the second partial flow path 73. For example, the first refrigerant flow path 71 may have only a flow path extending along a direction intersecting the penetration direction d1. In this embodiment, for example, when the first refrigerant flow path 71 is arranged in the second insert 35 as in the above embodiment, if a flow path communicating with the first refrigerant flow path 71 is appropriately arranged in the first insert 34 or the main mold 32, a cooling medium can be supplied to the first refrigerant flow path 71 from the outside.

[0039] (C2) In the above embodiment, the cooling unit 80 is configured by the first refrigerant flow path 71. However, the cooling unit 80 does not have to be configured by the first refrigerant flow path 71. For example, the cooling unit 80 may be configured by a Peltier element. In this case, the Peltier element may be arranged so that the surface of the Peltier element closer to the pressure pin 61 absorbs heat and the surface of the Peltier element farther from the pressure pin 61 dissipates heat, and the current supplied to the Peltier element may be controlled. The Peltier element may be arranged, for example, on the wall surface of the first wall portion 55 or within the first wall portion 55. Furthermore, to promote heat dissipation from the Peltier element, a heat dissipation unit configured by a heat pipe or a heat sink may be provided inside or outside the first wall portion 55. For example, when disposing the Peltier element within the first wall portion 55, a space for disposing the Peltier element, wiring, heat dissipation unit, etc. may be formed within the first wall portion 55 by additive manufacturing, cutting, discharge, etc., and then the Peltier element, wiring, heat dissipation unit, etc. may be disposed within the space. Furthermore, for example, by arranging a Peltier element so as to surround the periphery of the pressure pin 61, the cooling unit 80 arranged so as to surround the periphery of the pressure pin 61 may be realized.

[0040] (C3) In the above embodiment, the first step is performed in the manufacturing process of the mold structure 20, but the first step does not have to be performed. For example, instead of the first step, a step of forming the through holes 57 and the first refrigerant flow paths 71 in the metal material for forming the first wall portion 55 using a cutting tool, a laser, discharge, or the like may be performed. In other words, the first refrigerant flow paths 71 may be formed by a method other than additive manufacturing.

[0041] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0042] 20, 20b... mold structure, 30... main body portion, 31... fixed mold, 32... main mold, 33, 33b... nesting mold, 34... first nesting member, 35, 35b... second nesting member, 40... movable mold, 50, 50b... pressure mechanism, 55, 55b... first wall portion, 56... second wall portion, 57... through hole, 58... first hole portion, 59... second hole portion, 60... pressure portion, 61... pressure pin, 62... one end portion, 63... other end portion, 65... cylinder, 69... Arrangement chamber, 71, 71b...first refrigerant flow path, 72...first partial flow path, 73...second partial flow path, 75...third partial flow path, 76...first end, 77...second end, 79...supply section, 80, 80b...cooling section, 88, 88b...flow path, 89...second refrigerant flow path, 100...die casting device, 110...injection section, 111...injection plunger, 112...injection cylinder, 113...supply port, 114...molten metal flow path, 150...control section

Claims

1. A die structure for die casting, a wall portion having a through hole communicating with the cavity; a shaft-shaped pressure pin that is slidably disposed along an inner wall surface of the through hole and applies pressure to the molten metal in the cavity; a cooling portion provided on the wall portion and configured to cool the pressure pin, the cooling portion has a cooling flow path in the wall portion through which a cooling medium flows to cool the pressure pin, The cooling channel comprises: a first partial flow path extending in a direction perpendicular to the through-hole extending direction and having a first end and a second end, wherein a distance from the first end to the pressure pin is shorter than a distance from the second end to the pressure pin; a second partial flow path connected to the second end and extending along the penetration direction, a pair of the first partial flow paths are provided such that the pressure pin is disposed between the pair of first partial flow paths in the orthogonal direction, a pair of the second partial flow paths are provided such that the pressure pin is disposed between the pair of second partial flow paths in the orthogonal direction, A mold structure, wherein the cooling flow path further includes a third partial flow path connecting the first ends of the pair of first partial flow paths to surround the periphery of the pressure pin.

2. A mold structure according to claim 1, A mold structure, wherein the third partial flow path has a circular shape when viewed along the through direction.

3. A method for manufacturing a die structure for die casting, comprising: a first step of forming a wall portion having a through hole in which a shaft-shaped pressure pin that applies pressure to the molten metal in the cavity is disposed and a cooling flow path through which a cooling medium that cools the pressure pin flows; a second step of inserting the pressure pin into the through hole so that the pressure pin is slidable along an inner wall surface of the through hole, In the first step, a portion of the wall portion that defines the cooling flow path is formed by additive manufacturing, thereby forming the cooling flow path; The cooling flow path formed in the first step is a first partial flow path extending in a direction perpendicular to the through-hole extending direction and having a first end and a second end, wherein a distance from the first end to the pressure pin is shorter than a distance from the second end to the pressure pin; a second partial flow path connected to the second end and extending along the penetration direction, a pair of the first partial flow paths are provided such that the pressure pin is disposed between the pair of first partial flow paths in the orthogonal direction, a pair of the second partial flow paths are provided such that the pressure pin is disposed between the pair of second partial flow paths in the orthogonal direction, A method for manufacturing a mold structure, wherein the cooling flow path formed in the first step further includes a third partial flow path that is circular when viewed along the penetration direction and connects the first ends of the pair of first partial flow paths so as to surround the pressure pin.

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