Manufacturing method for die-cast products

Abstract

To provide a die-cast product production method which can produce a die-cast product having a complicated internal space and can suppress the remaining of unintentional gaps.SOLUTION: A die-cast product production method of the invention has: a first step of forming plural members 10, 20 for insert member formation to be joined so as to form into an insert member 30 having an internal space by die casting; a second step of forming the insert member 30 by joining the plural members 10, 20 for insert member formation; and a third step of forming a die-cast product in which the insert member 30 is wrapped in a cast-in member by die casting.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a die-cast product having an internal space.

Background Art

[0002] One of the currently widely used metal forming methods is die casting. According to die casting, by pressing molten metal into a mold, it is possible to manufacture a metal member with high dimensional accuracy in a short time (high cycle).

[0003] Metal products manufactured by die casting (hereinafter referred to as die-cast products) often take advantage of their high dimensional accuracy and are often treated as final products as they are or with only simple processing or treatment. On the other hand, since die casting is also one of the mold casting methods, there are limitations to the shapes of die-cast products that can be manufactured. For example, it is difficult or impossible to manufacture a die-cast product having a complex internal space (e.g., a bent heat exchange medium flow path) by general die casting.

[0004] As a technique for manufacturing a die-cast product having an internal space, for example, a member casting step of casting a member having a shape divided into a plurality of parts and a shape that can be die-cast, in a shape that can be nested (fitting by a convex shape and a concave shape) on the joint side of each member, and a joining step of inserting the base body formed by nesting each member at each joint into a joining mold provided with a cavity that can form a predetermined outer shape by surrounding the opposing surfaces of the base body at a predetermined interval and filling the cavity with molten metal to integrally solidify the molten metal on the base body to form a product. A die-cast casting manufacturing method is known (see Patent Document 1).

[0005] According to the conventional die-cast casting manufacturing method (hereinafter simply referred to as the "conventional method"), by providing an internal space inside the base body in which each member is nested, it becomes possible to manufacture a die-cast product having a complex internal space.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-346720 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, when die-cast products are actually manufactured using conventional methods, there is a problem in that unintended gaps remain between the components that make up the base body. These gaps can cause serious problems, such as leakage of the heat exchange medium (e.g., water) or damage to the die-cast product, when the internal space is used as a heat exchange medium channel.

[0008] The present invention has been made to solve the above problems, and aims to provide a method for manufacturing die-cast products that makes it possible to manufacture die-cast products having complex internal spaces and that can suppress the retention of unintended gaps. [Means for solving the problem]

[0009] The present invention provides a method for manufacturing a die-cast product, comprising: a first step of die-casting a plurality of insert member forming members, which, when joined together, form an insert member having an internal space; a second step of joining the plurality of insert member forming members to form the insert member; and a third step of die-casting a die-cast product in which the insert member is encased in a casting-encasing member. [Effects of the Invention]

[0010] The present invention's method for manufacturing die-cast products includes a third step of forming a die-cast product by die-casting, in which an insert member having an internal space is encased in a casting-encasing member. Therefore, it is possible to manufacture die-cast products having complex internal spaces, similar to conventional methods.

[0011] Furthermore, the method for manufacturing die-cast products of the present invention includes a second step of forming an insert member by joining multiple insert member forming members. Therefore, the multiple insert member forming members become a single insert member through joining. For this reason, the method for manufacturing die-cast products of the present invention makes it possible to suppress the retention of unintended gaps.

[0012] Therefore, the method for manufacturing die-cast products of the present invention makes it possible to manufacture die-cast products having complex internal spaces and to suppress the retention of unintended gaps.

[0013] In conventional methods, the cast components are joined together at their joints to form a base (corresponding to the insert component of the present invention). As a result, unintended gaps remain between the components constituting the base, both after the joining process and after subsequent product manufacturing. [Brief explanation of the drawing]

[0014] [Figure 1] This is a flowchart of the manufacturing method for a die-cast product according to the embodiment. [Figure 2] This figure illustrates the insert member forming member 10 formed in the first step S10 of the embodiment. [Figure 3] This figure illustrates the insert member forming member 20 formed in the first step S10 of the embodiment. [Figure 4] This is an enlarged cross-sectional view showing a portion of the planned joining surfaces 16 and 26 of the insert member forming members 10 and 20 after performing the fourth step S20 of the embodiment. [Figure 5] This figure is shown to illustrate the imparting of residual stress and lattice defects. [Figure 6] This figure shows the process of forming the insert member 30 in the second step S30 of the embodiment. [Figure 7] This figure illustrates the product mold 100 used in the third step S40 of the embodiment. [Figure 8] This is a diagram shown to explain the product mold 200 used in the third step S40 of the embodiment. [Figure 9] This is a cross-sectional view showing the state where the product molds 100 and 200 used in the third step S40 of the embodiment are combined. [Figure 10] This is a diagram showing the state of forming the die-cast product 40 in the third step S40 of the embodiment. [Figure 11] This is a diagram shown to explain the die-cast product 40 formed in the third step S40 of the embodiment.

Mode for Carrying Out the Invention

[0015] Hereinafter, the method for manufacturing a die-cast product of the present invention will be described based on the embodiments shown in the drawings. Each drawing is a schematic diagram and does not necessarily strictly reflect the actual structure, configuration, ratio, etc. The embodiments described below do not limit the invention according to the claims. Also, not all of the elements and combinations thereof described in the embodiments are essential for the present invention.

[0016] [Embodiment] FIG. 1 is a flowchart of a method for manufacturing a die-cast product according to an embodiment. As shown in FIG. 1, the method for manufacturing a die-cast product according to the embodiment includes a first step S10, a fourth step S20, a second step S30, and a third step S40. Hereinafter, each step will be described.

[0017] 1. First step S10 FIG. 2 is a diagram shown to explain the member 10 for forming an insert member formed in the first step S10 of the embodiment. FIG. 2(a) is a plan view of the member 10 for forming an insert member, and FIG. 2(b) is a cross-sectional view taken along the line A1 - A1 of FIG. 2(a). Figure 3 is a diagram illustrating the insert member forming member 20 formed in the first step S10 of the embodiment. Figure 3(a) is a plan view of the insert member forming member 20, and Figure 3(b) is a cross-sectional view taken along line A2-A2 in Figure 3(a).

[0018] The first step S10 is a process of die-casting multiple insert member forming members, which, when joined together, become an insert member 30 (described later) having an internal space 32. For this reason, the first step S10 can also be described as the "insert member forming member forming step." In this embodiment, insert member forming members 10 (see Figure 2) and insert member forming members 20 (see Figure 3) are formed as multiple insert member forming members.

[0019] As shown in Figure 2, the insert member forming member 10 has a recess 12 which, together with the recess 22 described later, becomes the internal space 32 when it is formed as an insert member 30. The recess 12 has a winding groove-like shape. In addition, communication openings 14 are formed at both ends of the recess 12. The surface indicated by reference numeral 16 in Figure 2 is the surface to be joined in the second step S30.

[0020] As shown in Figure 3, the insert member forming member 20 has a recess 22 which, together with the recess 12, becomes the internal space 32 when it is assembled into the insert member 30. The recess 22 has a winding groove shape. Note that the insert member forming member 20 does not have a communication opening 14. The surface indicated by reference numeral 26 in Figure 3 is the surface to be joined in the second step S30.

[0021] The insert member forming members 10 and 20 described above have shapes that can be easily formed by general die casting. For this reason, a detailed explanation of the formation of the insert member forming members 10 and 20 themselves will be omitted. Note that some or all of the recesses 12 and 22 and the communication opening 14 may be formed by post-processing (cutting or drilling) after die casting.

[0022] The material used to form multiple insert member forming members (insert member forming members 10, 20) in the first step S10 is the same material used to form the die-cast product 40 (described later) in the third step S40. In this specification, the identity of the material refers to an identity equivalent to that of the Japanese Industrial Standards (JIS).

[0023] The material used to form multiple insert member forming members (insert member forming members 10, 20) in the first step S10 and the material used to form the die-cast product 40 in the third step S40 are aluminum-based materials. In this specification, "aluminum-based material" refers to a material made of aluminum or an aluminum alloy. As the aluminum-based material, ADC-based materials (such as ADC12), which are alloys for die casting, can be suitably used.

[0024] 2. 4th process S20 Figure 4 is an enlarged cross-sectional view showing a portion of the planned joining surfaces 16 and 26 of the insert member forming members 10 and 20 after the fourth step S20 of the embodiment has been carried out. Figure 4(a) is an enlarged cross-sectional view showing a portion of the planned joining surface 16, and Figure 4(b) is an enlarged cross-sectional view showing a portion of the planned joining surface 26. Figure 5 is a diagram illustrating the application of residual stress and lattice defects. Figure 5(a) schematically shows the arrangement of atoms on the planned joining surface 16 of the insert member forming member 10 before residual stress is applied, Figure 5(b) schematically shows the arrangement of atoms on the planned joining surface 16 after residual stress is applied, Figure 5(c) is a schematic diagram illustrating a transition, which is a lattice defect, and Figure 5(d) is a schematic diagram illustrating a vacancy, which is a lattice defect. Figures 5(a) and 5(b) are oblique projection diagrams, and the round objects arranged in a cubic shape are atoms. Figure 5(c) is an oblique projection diagram, and Figure 5(d) is a plan view diagram. In Figures 5(c) and 5(d), the white circles represent atoms. Figure 5 is merely a schematic diagram and does not show the specific crystal structure of the planned joining surface 16. In Figure 5, atoms are depicted as having a simple cubic lattice structure, but this is for illustrative purposes only and does not indicate that the atoms in the insert member forming member 10 actually have such a structure. In Figures 5(a) and 5(b), reference numeral 10 indicates a part of the insert member forming member 10.

[0025] The fourth step S20 is a step in which residual stress is applied to at least the joining surfaces 16 and 26 of the insert member forming members 10 and 20 while leaving the surface chill layer. For this reason, the fourth step S20 can also be described as the "residual stress application step". The fourth step S20 is performed between the first step S10 and the second step S30.

[0026] In this specification, "chill layer" refers to a characteristic structure in a die-cast component (hereinafter referred to as "die-cast component"), specifically a relatively high-strength structure formed near the surface of the die-cast component. Die-cast components are formed by injecting molten metal into a mold under high pressure. The surface portion of the die-cast component is cooled more rapidly than the interior portion due to contact with the mold and other factors. As a result, a chill layer, which is a higher-density (less porous) structure than the interior, is formed on the surface of the die-cast component. While the chill layer does not have a clear boundary, for example, in a die-cast component formed using aluminum-based materials, it is considered appropriate to treat the area from the surface up to approximately 0.3 mm as the chill layer.

[0027] In this specification, "residual stress" refers to stress that exists (remains) within an object. Since stress remains within die-cast components even after manufacturing by die-casting, "to impart residual stress" in this specification can also be interpreted as "to increase residual stress."

[0028] In the fourth step S20, residual stress is applied by plastically deforming the surface of the target surface (at least the joining surfaces 16 and 26). Specifically, in the fourth step S20, residual stress is applied by shot blasting. Shot blasting is a process in which a projectile (granules) is impacted onto the target surface. The material of the projectile, the particle size, and the speed at which the projectile is impacted can be arbitrarily determined according to the type of material constituting the insert member forming members 10 and 20. However, when setting these conditions, care must be taken to ensure that the surface of the joining surfaces 16 and 26 is not abraded and the chill layer is not removed. As for the material of the projectile, for example, aluminum-based materials and steel materials can be suitably used. When shot blasting is performed, fine irregularities are formed on the surface of the joining surfaces 16 and 26 due to the impact of the projectile (see Figure 4). Note that Figure 4 is a schematic diagram, so the size, ratio, shape, etc. of the surface irregularities are not limited to those shown.

[0029] In addition, in the fourth step S20, residual stress may be applied to surfaces other than the planned joining surfaces 16 and 26 of the insert member forming members 10 and 20.

[0030] Here, the application of residual stress will be explained using the insert member forming member 10 as an example. By applying residual stress to the joining surface 16, the atomic-level structure (especially the metal crystal structure) of the joining surface 16 is affected (see Figures 5(a) and 5(b)), and the occurrence of lattice defects, which are disordered atomic arrangements, can be promoted. In particular, by applying residual stress to the joining surface 16 by plastically deforming the surface of the joining surface 16, it is possible to generate many transitions d1 (Figure 5(c)), which are linear lattice defects in which the atomic arrangement is shifted in rows. Furthermore, the application of residual stress can also generate vacancies d2 (see Figure 5(d)), which are point-like lattice defects, and planar lattice defects. The same applies to the insert member forming member 20.

[0031] Furthermore, it is preferable that the joining surfaces 16 and 26 each have a predetermined surface roughness. In this specification, "predetermined surface roughness" refers to a roughness that makes it easy to cause changes in the surface microstructure, such as deformation, fracture, and sliding of irregularities on the joining surfaces when pressure is applied to the joining surfaces for joining in the second step. The preferred numerical value for the predetermined surface roughness will vary depending on the type of material and the required joining strength, but it is generally considered preferable to set Ra = 0.05 μm or higher. In this specification, "surface microstructure" refers to the surface structure at the atomic scale.

[0032] 3.Second process S30 Figure 6 shows the process of forming the insert member 30 in the second step S30 of the embodiment. Figure 6(a) is a cross-sectional view showing the insert member forming member 10 and the insert member forming member 20 being pressed against each other, Figure 6(b) is an enlarged cross-sectional view showing the state of the planned joining surfaces 16 and 26 when pressed, Figure 6(c) is a cross-sectional view showing the insert member 30 formed by diffusion bonding, and Figure 6(d) is an enlarged cross-sectional view showing the state of the joining interface after joining. In Figure 6(a), the symbol P and the thick arrow indicate that the insert member forming member 10 and the insert member forming member 20 are being pressed against each other.

[0033] The second step S30 is a step in which an insert member 30 is formed by joining multiple insert member forming members (insert member forming members 10, 20). For this reason, the second step S30 can also be described as a "joining step". In the second step S30, the insert member 30 is formed by diffusion bonding multiple insert member forming members (insert member forming members 10, 20).

[0034] In the second step S30, with the planned joining surfaces 16 and 26 in contact, the insert member forming members 10 and 20 are relatively pressed against each other so that pressure is applied to the planned joining surfaces 16 and 26 (see Figure 6(a)), thereby diffusion bonding the insert member forming members 10 and 20. As a result, the insert member 30 is formed (see Figures 6(c) and 6(d)). In Figure 6(c), etc., the part indicated by reference numeral 10a is the part of the insert member forming member 30 that was the insert member forming member 10, and the part indicated by reference numeral 20a is the part of the insert member forming member 30 that was the insert member forming member 20. The dashed line in Figure 6(c) indicates the joining interface, but this dashed line does not indicate that the joining interface remains, but rather is intended to make it easier to understand that the illustrated object is formed from multiple members. The same applies to Figures 10 and 11, which will be described later.

[0035] In the second step S30, the insert member forming members 10 and 20 are pressed relative to each other, causing changes in the surface microstructure of the joining surfaces 16 and 26, and the insert member forming members 10 and 20 are diffusely bonded to form the insert member 30. Changes in the surface microstructure include deformation, fracture, and sliding of irregularities (see Figure 6(b)), and the combination of these and the residual stress applied to the joining surfaces 16 and 26 promotes diffusion bonding.

[0036] The principle by which diffusion bonding is promoted between joining surfaces to which residual stress is applied is thought to be as follows: By applying residual stress to each joining surface, the generation of lattice defects can be promoted at each joining surface, as described above. As the number of lattice defects increases, each joining surface becomes a state where atoms can easily move. As a result, it becomes possible to activate the diffusion of atoms and the establishment of metallic bonds between joining surfaces (joining interfaces).

[0037] In this specification, "relatively pressing the insert member forming members 10 and 20" does not only mean pressing one insert member forming member (e.g., insert member forming member 20) by fixing it and applying a moving force to another insert member forming member (e.g., insert member forming member 10). The insert member forming member to which the moving force is applied may be the opposite of the above. Furthermore, pressing may be performed by applying a moving force to both insert member forming members 10 and 20. Note that in Figure 6(a), the pressing is represented by a thick arrow P, but this is a schematic representation and does not indicate that pressure is concentrated at a specific point on the insert member forming member.

[0038] In the second step S30, it is preferable to heat the insert member forming members 10 and 20 to promote diffusion bonding and to carry out the process while maintaining the insert member forming members 10 and 20 at a certain temperature (however, below the melting point). That is, in the second step S30, it is preferable to relatively press the insert member forming members 10 and 20 under temperature conditions that enable diffusion bonding (preferably under temperature conditions suitable for diffusion bonding).

[0039] The optimal temperature conditions for diffusion bonding vary mainly depending on the type of material constituting the insert member forming members 10 and 20. For example, if the material is an aluminum-based material ADC12, the temperature can be set to around 500-550°C. Furthermore, the optimal pressure to be applied varies greatly depending on the type of material constituting the insert member forming members 10 and 20, the shape of the insert member forming members 10 and 20, the bonding temperature, etc., making it difficult to give an appropriate value, but it is generally considered that a pressure in the order of MPa is required.

[0040] When diffusion bonding insert member forming members 10 and 20, it is necessary to maintain a certain temperature and pressure to obtain a high bonding strength. The required duration varies depending on the type of material constituting the insert member forming members 10 and 20, the shape of the insert member forming members 10 and 20, the bonding temperature, pressure, etc., but can be, for example, 10 minutes to 3 hours.

[0041] The second step S30 is preferably carried out in a vacuum or in an inert gas. However, it is also possible to carry out the second step S30 in the presence of air.

[0042] In the second step S30, an insert member 30 is formed in which the internal space 32 communicates with the outside through two communication openings 14 (see Figure 6(c)).

[0043] 4. 3rd process S40 Figure 7 is a diagram illustrating the product mold 100 used in the third step S40 of the embodiment. Figure 7(a) is a plan view of the product mold 100, and Figure 7(b) is a cross-sectional view of Figure 7(a) taken along line A3-A3. Figure 8 is a diagram illustrating the product mold 200 used in the third step S40 of the embodiment. Figure 8(a) is a plan view of the product mold 200, and Figure 8(b) is a cross-sectional view of Figure 8(a) taken along line A4-A4. Figure 9 is a cross-sectional view showing the combined product molds 100 and 200 used in the third step S40 of the embodiment. Figure 10 shows the process of forming the die-cast product 40 in the third step S40 of the embodiment. Figures 10(a) to 10(d) are diagrams of each step. Figure 11 is a diagram illustrating the die-cast product 40 formed in the third step S40 of the embodiment. Figure 11(a) is a plan view of the die-cast product 40, and Figure 11(b) is a cross-sectional view of Figure 11(a) taken along line A5-A5.

[0044] The third step S40 is a process of die-casting a die-cast product 40 in which the insert member 30 is cast in a casting encasing member 42a. For this reason, the third step S40 can also be described as the "die-cast product formation process." The "die-cast product in which the insert member is cast in a casting encasing member" can also be described as "a die-cast product having a structure in which part or all of the insert member is covered with a casting encasing member."

[0045] First, the product molds 100 and 200 used in the third step S40 will be described. Note that whether one of the product molds 100 and 200 is movable or fixed is not relevant to the essence of the present invention, so the explanation will be omitted. Also, Figures 7 to 10 show only a part of the structure of the product molds 100 and 200, and the product molds 100 and 200 may have structures other than those shown or described. Examples of such structures include screw holes for fixing, holes for passing various pins, heat exchange medium channels, and spaces or holes for degassing.

[0046] As shown in Figure 7, the product mold 100 has a product-compatible portion 102 that corresponds to a part of the shape of the die-cast product 40. The product-compatible portion 102 has an insert member holding portion 104 that corresponds to the shape of a part of the insert member 30 (the part near the communication opening 14) and holds the insert member 30 when the mold is clamped. The product mold 100 also has a sprue 106 (runner) formed therein.

[0047] As shown in Figure 8, the product mold 200 has a product-compatible portion 202 that corresponds to a part of the shape of the die-cast product 40. The product-compatible portion 202 has an insert member holding portion 204 that corresponds to the shape of a part of the insert member 30 (the part near the communication opening 14) and holds the insert member 30 when the mold is clamped. The product mold 200 also has a sprue 206 (gate) formed therein. By combining (clamping) the product mold 100 and the product mold 200, a cavity C corresponding to the shape of the die-cast product 40 is formed (see Figure 9).

[0048] Next, the formation of die-cast products 40 using product molds 100 and 200 will be described. Note that die-casting requires not only molds but also opening and closing devices for the molds, injection devices for pouring molten metal into the molds, etc. However, these are common components and therefore will not be illustrated or explained.

[0049] First, the insert member 30 is placed in a predetermined position within the product-compatible portion 202 of the product mold 200 (see Figure 10(a)). In this embodiment, the insert member 30 is positioned so that the portion of the insert member 30 near the communication opening 14 is in contact with the insert member holding portion 104 (not shown by reference numeral in Figure 10).

[0050] Next, the product mold 200 and the product mold 100 are assembled (clamped together) to form the cavity C (see Figure 10(b)). At this time, the portion of the insert member 30 near the communication opening 14 is sandwiched between the insert member holding portion 104 and the insert member holding portion 204 (the reference numerals are not shown in Figure 10). In this way, the insert member 30 can be positioned so that at least a portion of it (in this embodiment, the portion other than the portion near the communication opening 14) is in contact with the cavity C of the product molds 100 and 200. In addition, the communication opening 14 is temporarily closed by the product molds 100 and 200 (specifically, by the insert member holding portion 204).

[0051] Next, molten metal 42 for casting is introduced into the cavity C via the runners 106 and 206 (not shown in Figure 10) (see Figure 10(c)). In this embodiment, the die-cast product 40 is formed with the communication opening 14 temporarily closed by the product molds 100 and 200 (specifically, by the insert member holding portion 204). In this specification, "temporarily closed communication opening" refers to a state in which the communication opening is closed so that it can be released after the die-cast product has been formed.

[0052] Subsequently, the molten metal 42 for casting is solidified to form the casting member 42a, thereby forming the die-cast product 40 (see Figure 10(d)). In die casting, the molten metal 42 for casting cools relatively quickly, so the insert member 30 does not melt. On the other hand, as the molten metal 42 for casting shrinks during the solidification process, it is thought that diffusion bonding or a similar phenomenon occurs between the insert member 30 and the molten metal 42 due to heat and pressure. As a result, the insert member 30 becomes one with the casting member 42a. Note that in Figure 10(d), etc., the part indicated by reference numeral 30a is the part of the die-cast product 40 that was the insert member 30.

[0053] Although a diagrammatic explanation is omitted, the die-cast product 40 can be removed by opening the product molds 100 and 200. After removing the die-cast product 40, processes such as removing solidified metal material and deburring, which are commonly performed in the field of die casting, can be carried out in the sprues 106 and 206.

[0054] The above process makes it possible to manufacture a die-cast product 40 having a complex internal space 32 (see Figure 11). The internal space 32 in the die-cast product 40 is a heat exchange medium flow path. By circulating a heat exchange medium (for example, a liquid such as water or oil, or a gas such as air or an inert gas) through the communication port 14 into the internal space 32, it is possible to cool or heat the die-cast product 40 or objects in contact with the die-cast product 40.

[0055] Die-cast products manufactured by the method for manufacturing die-cast products of the present invention, such as die-cast product 40 (which can utilize the internal space as a heat exchange medium flow path), can be used, for example, as temperature control members for regulating the temperature of power generation devices (engines, motors, etc.), power exchange and transmission devices (robot joints, transmissions, bearings, etc.), electronic components and modules (integrated circuits, semiconductor devices, modules thereof, etc.), lighting devices (headlights, taillights, etc. of vehicles, etc.), or energy storage devices (batteries, capacitors, etc.).

[0056] When die-cast products are temperature control components for regulating the temperature of power generation devices (engines, motors, etc.), rapidly removing the heat generated during use through the flow of a heat exchange medium makes it possible to maintain good performance of the power generation device for a long period of time. Furthermore, if the die-cast product is a temperature control component for regulating the temperature of power exchange and transmission devices (such as robot joints, transmissions, and bearings), rapidly removing the heat generated during use through the flow of a heat exchange medium makes it possible to allow the power exchange and transmission device to perform precise operation for extended periods. Furthermore, when die-cast products are temperature control components for regulating the temperature of electronic components and modules (integrated circuits, semiconductor devices, modules thereof, etc.), rapidly removing the heat generated during use through the flow of a heat exchange medium makes it possible to ensure that the electronic components and modules perform well for extended periods. Furthermore, if the die-cast product is a temperature control component for regulating the temperature of lighting devices (such as headlights and taillights of vehicles), rapidly removing the heat generated during use through the flow of a heat exchange medium makes it possible to ensure that the lighting device performs well for an extended period of time. Furthermore, when die-cast products are temperature control components for regulating the temperature of energy storage devices (batteries, capacitors, etc.), rapidly removing the heat generated during use (charging and discharging) through the flow of a heat exchange medium makes it possible to maintain good performance of the energy storage device for a long period of time. In addition, in cold regions, if the temperature of the energy storage device becomes too low, warming the die-cast product by circulating a warm heat exchange medium can suppress the performance degradation of the energy storage device due to low temperatures.

[0057] Furthermore, since the temperature control member, which is a die-cast product manufactured by the die-cast product manufacturing method of the present invention, controls temperature by the flow of a heat exchange medium, unlike existing heat sinks, there is no need to arrange bulky heat dissipation structures such as fins or pincushions near the object to be temperature controlled. For this reason, the temperature control member can be suitably used when it is not possible to secure a large space near the object to be temperature controlled, or when it is desired to miniaturize the area around the object to be temperature controlled. The temperature control member may be incorporated into the object to be temperature controlled, or it may be attached externally.

[0058] Furthermore, die-cast products manufactured by the die-cast product manufacturing method of the present invention can be used as heat exchange members to achieve heat exchange between high-temperature and low-temperature areas through the flow of a heat exchange medium. While a heat sink can only release absorbed heat into the surroundings, such a heat exchange member makes it possible to transfer absorbed heat to areas that require heating through the flow of a heat exchange medium. For example, in a hybrid car used in cold regions, the heat exchange member described above can be used to transfer heat absorbed from the engine to a power storage device or air conditioning system, thereby reducing energy waste and enabling temperature control of each device. The heat exchange member described above can also be considered part of a heat exchange system combined with a device for circulating a heat exchange medium. This heat exchange member is considered applicable to vehicles, factories, houses, and the like.

[0059] 5. Effects of the manufacturing method of die-cast products according to the embodiment

[0060] According to the method for manufacturing a die-cast product according to this embodiment, since it includes a third step S40 in which a die-cast product 40 is formed by die-casting an insert member 30 having an internal space 32 encased in a casting encasing member 42a, it is possible to manufacture a die-cast product 40 having a complex internal space 32, similar to conventional methods.

[0061] Furthermore, the method for manufacturing die-cast products according to this embodiment includes a second step S30 in which an insert member 30 is formed by joining a plurality of insert member forming members (insert member forming members 10, 20). Therefore, the plurality of insert member forming members (insert member forming members 10, 20) become a single insert member 30 through joining. For this reason, the method for manufacturing die-cast products according to this embodiment makes it possible to suppress the remaining unintended gaps.

[0062] Therefore, the method for manufacturing die-cast products according to this embodiment is capable of manufacturing die-cast products 40 having a complex internal space 32, and is also capable of suppressing the retention of unintended gaps.

[0063] Furthermore, the method for manufacturing a die-cast product according to this embodiment includes a second step S30 in which an insert member 30 is formed by joining a plurality of insert member forming members (insert member forming members 10, 20). Therefore, there is no need to form a structure (for example, a stepped labyrinth structure or extra internal space) to prevent the intrusion of molten metal 42 into the internal space 32 when the die-cast product 40 is formed by die-casting. This makes it possible to form an insert member 30 that is much thinner than conventional methods that use fitting.

[0064] Furthermore, according to the die-cast product manufacturing method of the embodiment, in the third step S40, the insert member 30 is positioned so that at least a portion of it is in contact with the cavity C of the product mold 100, 200 capable of forming the cavity C. Then, the molten metal for casting 42 is introduced into the cavity C, and the molten metal for casting 42 is solidified to form a casting member 42a, thereby forming the die-cast product 40. This makes it possible to reliably cast and encase the insert member 30.

[0065] Furthermore, according to the die-cast product manufacturing method of the embodiment, the material used to form the multiple insert member forming members (insert member forming members 10, 20) in the first step S10 is the same as the material used to form the die-cast product 40 in the third step S40. Therefore, it is possible to reduce the stress (especially thermal stress) generated between the portion 30a that was the insert member 30 and the casting member 42a, and to manufacture a die-cast product 40 in which the portion 30a that was the insert member 30 and the casting member 42a are less likely to separate even with temperature changes.

[0066] Furthermore, according to the die-cast product manufacturing method of the embodiment, the material used to form a plurality of insert member forming members (insert member forming members 10, 20) in the first step S10 and the material used to form the die-cast product 40 in the third step S40 are aluminum-based materials. Therefore, by taking advantage of the strength and lightness of aluminum-based materials, it is possible to manufacture die-cast products 40 that can be used in various fields.

[0067] Furthermore, according to the manufacturing method of die-cast products according to the embodiment, a fourth step S20 is included between the first step S10 and the second step S30 in which residual stress is applied to at least the joining surfaces 16, 26 of the insert member forming members 10, 20 while leaving a surface chill layer. In the second step S30, the insert member 30 is formed by diffusion bonding a plurality of insert member forming members (insert member forming members 10, 20). Therefore, it becomes possible to bond a plurality of insert member forming members (insert member forming members 10, 20) formed by die casting, which is generally considered difficult to achieve high bonding strength with, with high bonding strength.

[0068] Furthermore, according to the method for manufacturing die-cast products according to the embodiment, in the fourth step S20, residual stress is applied by shot blasting, making it possible to apply residual stress while forming fine irregularities in a simple manner.

[0069] Furthermore, according to the die-cast product manufacturing method of the embodiment, in the second step S30, an insert member 30 is formed in which the internal space 32 is in communication with the outside through two communication openings 14, and in the third step S40, the die-cast product 40 is formed with the communication openings 14 closed, so that the internal space 32 can be used as a space that can exchange fluid with the outside (for example, a heat exchange medium flow path).

[0070] Although the present invention has been described above based on the embodiments described above, the present invention is not limited to the embodiments described above. It can be implemented in various forms without departing from the spirit of the invention, and for example, the following modifications are also possible.

[0071] (1) The shapes of the insert member forming members 10, 20, the insert member 30, and the die-cast product 40 in the above embodiment are merely illustrative, and any shape can be used as long as it does not deviate from the scope of the present invention.

[0072] (2) In the above embodiment, the plurality of insert member forming members consisted of two insert member forming members 10 and 20, but the present invention is not limited thereto. The plurality of insert member forming members may consist of three or more insert member forming members. When the plurality of insert member forming members consist of three or more insert member forming members, in the second step, all insert member forming members may be joined at once, or they may be joined two at a time.

[0073] (3) In the above embodiment, the material used to form the multiple insert member forming members (insert member forming members 10, 20) in the first step S10 is the same as the material used to form the die-cast product 40 in the third step S40, but the present invention is not limited thereto. The material used to form the multiple insert member forming members in the first step may be different from the material used to form the die-cast product in the third step.

[0074] (4) In the above embodiment, the material used to form the multiple insert member forming members (insert member forming members 10, 20) in the first step S10 and the material used to form the die-cast product 40 in the third step S40 were aluminum-based materials, but the present invention is not limited thereto. Any metal material that can be die-cast can be applied to the present invention.

[0075] (5) In the above embodiment, residual stress is applied by plastically deforming the surface of the target surface, but the present invention is not limited thereto. Residual stress may be applied to the target surface by means other than plastic deformation (for example, heat treatment such as rapid cooling).

[0076] (6) In the above embodiment, residual stress is imparted by shot blasting, but the present invention is not limited thereto. Residual stress may be imparted by treatment other than shot blasting.

[0077] (7) In the above embodiment, in the second step S30, an insert member 30 was formed in which the internal space 32 communicates with the outside through at least two communication openings 14, but the present invention is not limited thereto. The number of communication openings can be changed depending on the application and the shape of the internal space, and there may be one or three or more. Furthermore, if the internal space is formed for purposes such as heat insulation or weight reduction, there may be no communication openings.

[0078] (8) The present invention may further include a fifth step after the third step, in which a protective layer is formed on the wall surface constituting the internal space. Examples of the protective layer include a resin layer and an oxide film layer. The resin layer can be formed by dipping or the like. The oxide film layer can be formed by anodizing or the like. [Explanation of Symbols]

[0079] 10,20…Insert member forming member, 10a,20a…Part of the insert member that was the insert member forming member, 12,22…Recess, 14…Communication opening, 16,26…Joining surface, 30…Insert member, 30a…Part of the die-cast product that was the insert member, 32…Internal space, 40…Die-cast product, 42…Molten metal for casting, 42a…Casting member, 100,200…Product mold, 102,202…Product corresponding part, 104,204…Insert member holding part, 106,206…Runner, C…Cavity

Claims

1. A first step involves die-casting multiple insert member forming members, which, when joined together, form an insert member having an internal space. A second step of forming the insert member by joining the plurality of insert member forming members, The process includes a third step of forming a die-cast product by die-casting, in which the insert member is encased in a casting-encasing member. A method for manufacturing a die-cast product, characterized in that, in the second step, the plurality of insert member forming members are pressed relative to each other under temperature conditions that enable diffusion bonding of the plurality of insert member forming members, and the insert member is formed by solid-phase diffusion bonding of the plurality of insert member forming members.

2. The method for manufacturing a die-cast product according to claim 1, characterized in that, in the third step, the insert member is positioned so as to be in contact with at least a portion of the cavity of a product mold capable of forming a cavity, then molten metal for casting is introduced into the cavity, and the molten metal for casting is solidified to form the casting member, thereby forming the die-cast product.

3. The method for manufacturing a die-cast product according to claim 1 or 2, characterized in that the material used to form the plurality of insert member forming members in the first step is the same as the material used to form the die-cast product in the third step.

4. The method for manufacturing a die-cast product according to claim 3, characterized in that the material used to form the plurality of insert member forming members in the first step and the material used to form the die-cast product in the third step are aluminum-based materials.

5. In each of the insert member forming members that constitute the plurality of insert member forming members, when the surface to be joined in the second step is designated as the surface to be joined, A method for manufacturing a die-cast product according to claim 1 or 2, characterized in that a fourth step of applying residual stress to at least the joining surface of the insert member forming member while leaving a surface chill layer is included between the first step and the second step.

6. The method for manufacturing a die-cast product according to claim 5, characterized in that the residual stress is imparted by shot blasting in the fourth step.

7. In the second step described above, the insert member is formed such that its internal space is connected to the outside by at least one communication opening. The method for manufacturing a die-cast product according to claim 1 or 2, characterized in that the die-cast product is formed with the communication opening temporarily closed in the third step.

8. The method for manufacturing a die-cast product according to claim 7, further comprising a fifth step of forming a protective layer on the wall surface constituting the internal space after the third step.

9. The method for manufacturing a die-cast product according to claim 7, characterized in that the die-cast product is a temperature control member for adjusting the temperature of a power generator, a power exchange / transmission device, an electronic component / module, a lighting device, or an energy storage device.

10. The method for manufacturing a die-cast product according to claim 7, characterized in that the die-cast product is a heat exchange member for achieving heat exchange between a high-temperature part and a low-temperature part by the flow of a heat exchange medium.

11. The internal space is a heat exchange medium flow path, The method for manufacturing a die-cast product according to claim 1, characterized in that, in the die-cast product, a heat exchange medium can be circulated through the internal space to cool or heat the die-cast product or objects in contact with the die-cast product.

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