WO2021020529A1

WO2021020529A1 - Heat sink

Info

Publication number: WO2021020529A1
Application number: PCT/JP2020/029317
Authority: WO
Inventors: 中嶋　英雄
Original assignee: 株式会社ロータスマテリアル研究所
Priority date: 2019-07-30
Filing date: 2020-07-30
Publication date: 2021-02-04
Also published as: JP2021027357A; JP7165361B2

Abstract

[Problem] To provide a heat sink in which it is possible to omit a base member, an operation for joining to a base member, etc., and which can be manufactured for lower cost, the heat sink furthermore being such that: it is possible to provide a curved through-hole having a longer and narrower shape; it is possible to suitably and freely set the overall shape and dimensions of the heat sink, as well as the shape and dimensions of the through-hole provided therein; and the heat sink has a greatly improved degree of freedom in terms of design and exceptional cooling performance. [Solution] A heat sink 1 characterized by being formed from a cast article of a metal material, and also characterized in that one or a plurality of heat-resistant-wire drawing holes 10 passing through the heat sink 1 open in the outer surface thereof, and heat is dissipated into a fluid flowing through the heat-resistant-wire drawing holes 10. The drawing holes 10 are drawing holes of one or a plurality of heat-resistant wires that are provided in a mold of the cast article and that are embedded in the metal material being solidified in a state, in which end parts of the heat-resistant wires are exposed at the outer surface.

Description

heat sink

The present invention relates to a heat sink capable of dissipating heat in the fluid by circulating the fluid through the through hole.

A heat sink using a porous metal material can increase the surface area in contact with the fluid by passing a fluid such as a refrigerant through the pores, so that it can be used as a heat sink (grooved heat sink) consisting of simple plate-shaped fins that are not porous. You can dominate in comparison. For example, a lotus metal molded product is known as one of the porous metal materials. The lotus metal molded body is a metal molded body produced by a known method such as a high pressure gas method (Pressurized Gas Method) or a thermal decomposition method (Thermal Decomposition Method), and has pores elongated in one direction (for example, Patent Document 1). reference.). By cutting this into a thin plate having a plurality of through holes, a porous metal plate (lotus metal plate) having a large number of through holes can be obtained. The lotus metal plate has excellent heat transfer properties, and its use as a heat sink for electronic devices and various heat exchange fins has been proposed (see, for example, Patent Documents 2 and 3).

However, since the lotus metal molded body has a limited length of pores, the hole of the lotus metal plate is used as a through hole, so that the plate thickness after cutting is limited. Therefore, in order to secure the volume for heat absorption, a plurality of such lotus metal plates are arranged in succession on the base material as a base material at intervals. The process of thinning the sheet and joining the lotus metal plate to the base material complicates the process, and it is important to maintain the quality (thermal conductivity, strength, etc.) of the joints, which limits the reduction of manufacturing costs. was there.

Other methods for producing porous metal materials include a method of mechanically drilling holes in post-processing, and a method of melting and evaporating metal using an electron beam or a laser to drill holes. However, the smaller the hole, the easier it is to break, the longer the machining time is, the higher the cost, and the length of the hole is limited by the length of the drill tool. The electron beam requires high vacuum equipment, is expensive, and is not suitable for industrialization. Laser machining is possible in the atmosphere, but drilling requires a great deal of money and time. Further, in the processing by an electron beam or a laser, the ratio of the length to the diameter of the hole (aspect ratio) is at most about 10, and there is a limit to drilling a long and thin hole.

Further, all of the above-mentioned conventional porous metal materials can have only linear holes extending in one direction. This is because the lotus metal molded body uses unidirectional solidification due to its manufacturing method, and drilling, electron beam processing, etc. are also linear drilling processes. If thinner, longer, and curved holes can be produced, the degree of freedom in design can be significantly improved, and a heat sink having excellent performance can be provided.

Japanese Patent No. 4217865 JP-A-2018-73869 Japanese Unexamined Patent Publication No. 2018-179412

Therefore, in view of the above-mentioned situation, the present invention tries to solve the problem by omitting the base material and the joining work to the base material, and can be manufactured at a lower cost. It is possible to provide long, thin, and curved through holes, and the overall shape and dimensions, as well as the form and dimensions of the through holes, can be freely set as appropriate, dramatically increasing the degree of freedom in design. The point is to provide a heat sink having excellent cooling ability as well as being improved.

The present invention includes the following inventions.
(1) It is made of a cast metal material, and has a single or a plurality of penetrating heat-resistant wire drawing holes on the outer surface, and heat is dissipated into the fluid flowing through the heat-resistant wire drawing holes. heat sink.

(2) The heat-resistant wire drawing hole is a single or a plurality of heat-resistant wire drawing holes that are provided in the mold of the cast product and are embedded in a metal material that solidifies with the ends exposed on the outer surface (1). ) Described heat sink.

(3) The heat sink according to (2), wherein the heat-resistant wire has a surface coated with a release agent.

(4) The heat sink according to (2) or (3), wherein the heat-resistant wire is a thin metal wire having predetermined shape retention and bending deformation possibility.

(5) The cast product is provided with a bottomed hole having a cross-sectional area larger than the cross-sectional area of the drawn hole, and the heat-resistant wire drawn-out hole is formed from the opening on the outer surface of the cast product to the inner circumference of the hole. The heat sink according to any one of (1) to (4), which is a through hole leading to an opening on the surface and is a hole that communicates the space inside the hole with the external space of the casting.

(6) The heat-resistant wire drawing hole is in any of (1) to (5), which is linear, curved (for example, wavy, spiral, etc.) or bent (bent in a plurality of directions). The heat sink described.
(7) The heat sink according to any one of (1) to (6), wherein the heat-resistant wire drawing hole has a hole diameter (diameter) of 100 μm to 20 mm, preferably 200 μm to 10 mm, and more preferably 300 μm to 5 mm.
(8) The heat sink according to any one of (1) to (7), wherein the length of the heat-resistant wire drawing hole is 1 mm to 2000 mm, preferably 5 mm to 1000 mm, and more preferably 10 mm to 300 mm.
(9) The heat sink according to any one of (1) to (8), wherein the heat-resistant wire drawing hole has an aspect ratio of 0.05 to 20000, preferably 1 to 1000, and more preferably 3 to 300.

(10) The heat sink according to any one of (1) to (9), which is made of a cast product of a metal material of aluminum, aluminum alloy, copper, copper alloy, magnesium, or magnesium alloy.

(11) The method for manufacturing a heat sink according to any one of (1) to (10), wherein a single or a plurality of heat-resistant wires are provided in a mold, a molten metal material is supplied and solidified, and then the above. A manufacturing method for obtaining a heat sink made of a cast metal material in which one or a plurality of penetrating heat-resistant wire drawing holes are opened on the surface by drawing out the heat-resistant wire.
(12) The production method according to (11), wherein the surface of the heat-resistant wire is coated with a mold release agent in advance before supplying the molten metal material at the latest.

(13) The manufacturing method according to (11) or (12), wherein the heat-resistant wire is a thin metal wire having a predetermined shape retention property and bending deformation possibility.
(14) After the solidification and demolding, the heat-resistant wire is drawn from the cast product of the metal material to obtain a cast product of the metal material in which one or more heat-resistant wire drawing holes are opened on the surface (11). )-(13). The method for producing a perforated casting product.

(15) The heat-resistant wire is linear, curved (for example, wavy, spiral, etc.) or bent (bent in a plurality of directions), and if it is curved or bent, it is bent and deformed. The manufacturing method according to (11), wherein the heat-resistant wire drawing hole having a linear shape, a curved shape, or a bending shape is obtained by pulling out the heat-resistant wire.

According to the present invention as described above, since a heat sink having a relatively long and thin through hole can be obtained by drawing out the heat-resistant wire, such a heat sink omits the work of joining the base material and the base material. This makes it possible to manufacture at a lower cost than cut products of lotus metal molded products and post-processed products such as drills, electron beams, and lasers.

In addition, it is possible to provide a longer, thinner, and curved through hole, and the overall shape and dimensions, as well as the form and dimensions of the through hole, can be freely set as appropriate, greatly increasing the degree of freedom in design. It is possible to provide a heat sink having excellent cooling ability as well as being improved. The present inventor has confirmed that long and narrow holes having an aspect ratio of 786 can be easily provided. It has also been confirmed that curved or polygonal holes can be provided. The diameter of the pores can be about 100 μm to 20 mm.

Perspective view showing a heat sink according to a typical embodiment of the present invention. The perspective view which shows the other example of the heat sink which concerns on the typical embodiment of this invention. Explanatory drawing which shows an example of the drawing hole which is also formed in the heat sink. Explanatory drawing which shows another example of the drawing hole which is also formed in the heat sink. Explanatory drawing which shows still another example of the drawing hole which is also formed in the heat sink. Explanatory drawing which also shows another example of a heat sink. Explanatory drawing which also shows still another example of a heat sink. Explanatory drawing which also shows still another example of a heat sink. Explanatory drawing which also shows still another example of a heat sink. Explanatory drawing which also shows still another example of a heat sink. A perspective view showing still another example of the heat sink. Similarly, a plan view excluding the object to be cooled. Also side view. A perspective view showing still another example of the heat sink. Similarly, a plan view excluding the object to be cooled. Also side view. An explanatory view showing an example of a heat sink manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Explanatory drawing which also shows another example of a manufacturing procedure. Explanatory drawing which also shows still another example of a manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Similarly, an explanatory diagram of the manufacturing procedure. Vertical cross-sectional view showing a modified example of the extraction hole The explanatory view which shows the heat-resistant wire used for forming the drawing hole of FIG. 12A.

Next, an embodiment of the present invention will be described in detail based on the accompanying drawings.

The heat sink 1 according to the present invention is made of a perforated cast product made of a metal material, and as shown in FIGS. 1A and 1B, one or a plurality of through heat-resistant wire drawing holes 10 are opened on the surface. Then, the heat sink 1 absorbs heat by adhering to a cooling object 8 such as a heating element or a base surface thermally connected to the heating element, and at the same time, a refrigerant or the like flowing on the surface thereof or through the drawing hole 10. Dissipates heat into the fluid.

The fluid to be circulated in the drawing hole 10 corresponds to air, argon gas, nitrogen gas, water, gas such as various coolants, liquid, and the like. As the metal material constituting the heat sink 1, various metal materials having high thermal conductivity such as aluminum, copper, magnesium, silver, iron, and various alloys and compounds thereof can be used. Since the pull-out hole 10 can be a long through hole that does not reduce the pressure loss of the refrigerant fluid as compared with the short through hole of the conventional Lotus metal plate, cutting into a thin plate or joining to the base material is omitted. It can be done, the cost can be reduced, and the quality can be stabilized.

The heat-resistant wire drawing hole 10 is a hole formed by drawing a heat-resistant wire from a solidified casting as described later, and its cross-sectional shape reflects the cross-sectional shape of the heat-resistant wire, and is oval, triangular, or quadrangular in addition to a circular shape. , Hexagonal, L-shaped and other various cross-sectional shapes are possible. The cross-sectional area (opening area) also reflects the cross-sectional area of the heat-resistant wire as it is, and it is possible to easily form thin and long holes that were difficult with conventional Lotus molded bodies, drilling, laser machining, and the like. Further, as shown in FIG. 12A, it is also a preferable example that the withdrawal hole 10 has a cross-sectional area that changes periodically along the axial direction to form irregularities (undulations) along the axial direction on the inner peripheral surface. As shown in FIG. 12B, the drawing hole 10 having irregularities in the axial direction has the thickness of the release agent layer 9 formed in advance on the outer peripheral surface of the heat-resistant wire 2 to be used along the axial direction. By changing it periodically, it is possible to form irregularities (undulations) having the same period corresponding to the solidified inner peripheral surface of the extraction hole 10. If the release agent remains in the recesses of the holes, it can be washed and washed away to obtain an inner peripheral surface having the unevenness (undulations). As a result, the contact area (contact distance per unit length in the axial direction) between the refrigerant or the like passing through the drawing hole 10 and the inner peripheral surface of the hole can be increased, and the cooling capacity can be increased.

The length of the heat-resistant wire drawing hole 10 is 2000 mm or less, preferably 1000 mm or less, and more preferably 300 mm or less. If it is longer than 2000 mm, the heat-resistant wire also becomes longer, the contact area with the casting increases, the frictional force at the time of drawing increases, and the drawing becomes difficult. The hole diameter (diameter) of the heat-resistant wire drawing hole is 100 μm to 20 mm, preferably 200 μm to 10 mm, and more preferably 300 μm to 5 mm.

If the hole diameter is smaller than 100 μm, the heat-resistant wire will also become considerably thin, and it will be easily damaged during drawing, making it difficult to manufacture a perforated cast product. When the hole diameter is larger than 20 mm, the contact area between the heat-resistant wire to be used and the casting increases, the frictional force at the time of pulling out increases, and the pulling out tends to be difficult. The drawing hole 10 can be easily formed by using a heat-resistant wire having a medium thickness.

However, if the length of the drawing hole 10 becomes too long, there is a demerit that the pressure loss due to the flow of a fluid such as a refrigerant increases. The smaller the pore diameter, the more the effect of pressure loss cannot be ignored. For example, when the refrigerant is circulated through the extraction hole 10 by a pump, if this pressure loss becomes large, a larger pump power is required to pass the refrigerant through the extraction hole 10, which may lead to an increase in operating cost.

As an example of the pull-out hole 10 for reducing such pressure loss, as shown in FIG. 2A, the fluid is stored in the middle of the through-through pull-out hole through which the fluid flows and branches laterally to recover the pressure. It is also preferable to provide the created fluid storage space 14 through a drawing hole 10 or the like. In this example, the fluid storage space 14 is formed in the vertical direction intersecting the drawing hole 10 extending in the horizontal direction shown in the drawing, and the drawing opening on the lower surface side is closed with a closing member 13 made of metal or the like having excellent thermal conductivity. Is formed by. Such intersecting fluid reservoir spaces 14 may be formed by crossing the heat-resistant wires in a state of being in contact with each other, or by allowing one heat-resistant wire to pass through the other heat-resistant wire and pulling out the other first. This can be achieved by introducing a cut surface in the direction perpendicular to the hole direction. For example, a cast product having the drawn-out hole formed through which a fluid flows is post-processed to make a cut by laser processing or the like from the side intersecting the drawn-out hole toward an intermediate position of the drawn-out hole. It is also possible to form the fluid storage space 14 and close the side opening surface thereof with a closing member. Further, as shown in FIG. 2B, as a tapered hole having a gradient in thickness along the length direction, the area of the hole on the downstream side is gradually increased (assuming that the fluid flows from the left to the right in the figure), or the figure. Pressure loss can be reduced by taking various measures that can be configured as extraction holes, such as branching holes as shown in 2C and increasing the total cross-sectional area of the holes on the downstream side (assuming fluid flows from left to right in the figure). Can solve the problem. The hole branched in the middle of the inside shown in FIG. 2C can be easily realized by using a heat-resistant wire that also branches. This cannot be realized with a lotus metal molded product, and drilling and the like are extremely costly.

Further, as shown in FIG. 3, a large number of through holes 10 extending in different directions can be easily provided by appropriately setting the arrangement of the heat-resistant wire at the time of casting the perforated cast product. The heat sink 1 provided with such multi-directional drawing holes 10 cannot be manufactured by a lotus metal molded body in which unidirectional pores are formed, and drilling, electron beam machining, and laser machining take time and the apparatus becomes large. The cost will be high.

Further, by using a thin metal wire having a predetermined shape-retaining property and a possibility of bending and deforming, a curved (wavy or spiral) or curved hole can be formed as shown in FIGS. 4A to 4D. You can also do it. This makes it possible to increase the length of the drawing hole and provide a heat sink having better cooling performance. When the object to be cooled has a complicated shape, there are some parts that cannot be cooled by a straight through hole. However, if the holes are spiral, V-shaped, or curved as in this example, it is possible to handle the cooling of the entire surface of a complicated object to be cooled that cannot be covered by a straight hole, and effective and efficient cooling can be performed. Can be done. Such holes cannot be formed by cutting a conventional Lotus metal molded body, drilling, electron beam processing, or laser processing.

For example, when the object to be cooled (heat sink, etc.) is locally uneven, is asymmetric in plane, or the heat generating part and the heat non-generating part are intricately inserted, the cooling object is basically When it has a complicated shape, a portion that cannot be covered by a straight hole may remain, but as shown in FIG. 4B, the contact surface of the heat sink 1 with respect to the uneven cooling object 8 The pull-out hole 10 can be appropriately bent so as to follow the uneven shape, and can be provided by being curved so as to project inside the convex portion, for example, and it is possible to provide a heat sink having more excellent cooling performance. ..

5A to 5C are configuration examples for promoting the flow of a fluid such as a refrigerant through the long drawing hole 10 in which the pressure loss tends to be large, and the bottom having a cross-sectional area larger than the cross-sectional area of the drawing hole 10. The hole 11 is provided, and the heat-resistant wire drawing hole 10 is a through hole extending from the opening on the outer surface of the cast product (heat sink 1) to the opening on the inner peripheral surface of the hole 11, and is inside the hole 11. It is a hole that communicates the space and the external space of the cast product (heat sink 1). In such an example, by positively supplying a fluid such as a refrigerant to the hole 11 by pressurization or the like, the fluid supplied to the hole 11 opens to the inner peripheral surface of the hole 11. It is forcibly supplied to each drawing hole 10, the flow of the fluid through the drawing hole 10 is promoted, and the cooling effect can be improved.

6A to 6C are the same as those in FIG. 5 except that each of the drawing holes 10 is a curved hole (logarithmic spiral curve shape) inclined in one direction in the circumferential direction toward the outer peripheral side in the radial direction from the axial center of the hole portion 11. Is. By making the drawing holes 10 curved in one direction in this way, the contact area with the fluid is increased, the cooling efficiency can be further improved, and all the drawing holes 10 are curved in the same direction. Therefore, it is possible to generate a vortex flow in the fluid in the hole 11 and further promote the supply of the fluid to the drawing hole 10.

FIG. 7A and below exemplify the manufacturing method of the heat sink 1. Such a manufacturing method is the same as the method of Japanese Patent Application No. 2019-107040 “Perforated cast product and its manufacturing method” previously proposed by the present inventor, and all the contents of the application are incorporated herein by reference. it can. In the example shown in FIG. 7A, the mold 3 is integrated with the plate-shaped plate mold 30 that forms the bottom surface of the cast product and supports the heat-resistant wire 2 so as to project upward, and the plate mold 30 and the heat-resistant wire. 2 is inside, and it is composed of a combination with a container-shaped outer mold 31 that forms an outer peripheral surface of a cast product. FIG. 7B shows a state in which the plate mold 30 and the heat-resistant wire 2 are set inside the outer mold 31. It is preferable that the upper surface of the plate mold 30 is formed with a supporting recess for inserting and supporting the lower end of the heat resistant wire 2.

A mold release agent is applied to at least the outer surface of the heat resistant wire 2. In addition to the heat-resistant wire 2, it is preferable that the release agent is applied to the upper surface of the plate mold 30 and the inner peripheral surface of the outer mold 31. As for the timing of applying the release agent, the release agent may be applied to the integrated plate mold 30 and the heat-resistant wire 2 in advance and set on the outer mold 31 after drying, or may be applied after the setting. You can also.

As the release agent, various known release agents can be used depending on the metal material used. Specifically, a known mold release agent containing boron nitride (boron nitride), alumina (alumina cement), graphite, fullerene, silicon, molybdenum disulfide, chromium oxide, etc. as the main components is used as the metal material to be used. You can choose according to your needs. For example, in the case of aluminum or magnesium, a mold release agent containing boron nitride as a main component is preferable, and in the case of copper or silver, a mold release agent containing alumina as a main component is preferably used. In addition, the mold release agent must be selected so that the maximum temperature capable of retaining the mold release function is higher than the melting point of the metal material used. In order to improve the wettability and adhesion between the mold release agent and the surface of the heat-resistant wire, an organic solvent or the like may be added to the main component for mold release. However, when the organic solvent reacts with the molten material to reduce the mold release functionality, the mold release main material alone can be applied to the heat-resistant wire.

Then, in a state where the mold 3 (outer mold 31) is appropriately heated, as shown in FIG. 8A, a separately melted metal material (for example, molten aluminum) (hereinafter, referred to as “molten material (12)”) is a heat-resistant wire. After pouring hot water into the mold 3 in which 2 is erected, the mixture is cooled and solidified in the state shown in FIG. 8B. The molten material 12 is filled in the gap between the heat-resistant wires 2 and solidifies in a state of being integrated with the heat-resistant wires 2. The method of supplying the molten material may be one in which a solid metal material (solid material) is set on the upper part of the mold, melted by heating, and moved into the lower mold.

If the pouring is stopped when the upper end of the heat-resistant wire 2 protrudes from the surface of the hot water, the drawing hole of the heat-resistant wire becomes a through hole. If the distance between the heat-resistant wires 2 is small, the immersion of the molten material may be insufficient due to surface tension and viscosity. In such a case, a stirring means using a thin ceramic rod or a vibrating means may be used. It is preferable to provide it.

After the molten material has solidified, as shown in FIG. 9A, the plate mold 30 is separated from the outer mold 31 by pushing it up with a pin (not shown) from below, and the metal material casting 4 integrated with the heat resistant wire 2 is formed. Take out the plate mold 30 resting on the upper surface side. Here, the side wall and the bottom wall of the outer mold 31 can be separated, and the bottom wall can be removed and taken out from the bottom side, of course.

Then, as shown in FIG. 9B, while the side surface 4b of the casting 4 is supported by being sandwiched by the jig 5, the plate mold 30 on the lower surface side is removed, and the lower end of each exposed (protruding) heat-resistant wire 2 is removed. As shown in FIG. 9C, the portion 2a is picked with a holding jig 6 or the like and pulled downward as it is, whereby a pull-out hole 10 penetrating the casting 4 is formed, and the heat sink 1 is completed. The exposure of the lower end portion 2a at the time of pulling out protrudes by the depth of the supporting recess. Since the heat-resistant wire 2 is also exposed upward, it can be pulled out upward from the upper end of the heat-resistant wire 2.

In this example, as shown in FIGS. 9B and 9C, after removing the plate mold 30 from the casting 4, the heat-resistant wire 2 is pulled out with the jig 6, but the plate mold 30 and the heat-resistant wire 2 are mutually connected. It is also preferable from the viewpoint of efficiency that the heat-resistant wire 2 is also configured to move downward together with the plate mold 30 and be pulled out when the plate mold 30 is removed by firmly fixing the plate mold 30. That is, the heat-resistant wire can be pulled out from the casting after the mold is removed, or the heat-resistant wire can be integrally provided in the mold so that the heat-resistant wire can be pulled out together with the mold during the mold removal.

In the example of the manufacturing apparatus shown in FIGS. 11A to 11D, as shown in FIG. 11A, the plate mold 30 and the heat-resistant wire 2 firmly fixed to each other are set in the crucible-shaped outer mold 31, and the inside of the outer mold 31 is set. By inserting a solid metal material (solid material 9) into the upper part of the heat-resistant wire 2 and heating it with a heater 7, the solid material 9 is melted as shown in FIG. 11B, and the molten material is placed between the heat-resistant wires 2. This is an example of filling and solidifying the gap. Then, after taking out the plate mold 30 in a state where the casting 4 of the metal material integrated with the heat-resistant wire 2 is placed on the upper surface side as shown in FIG. 11C from the outer mold 31, the plate mold 30 is as shown in FIG. 11D. By separating the heat-resistant wire 2 from the casting 4, the heat-resistant wire 2 is also pulled out together with the plate mold 30, and a heat sink made of a perforated casting can be efficiently obtained.

The above example is a manufacturing method in which a heat-resistant wire is arranged in the vertical direction and a drawing hole is formed in the vertical direction, but of course it can also be formed in the horizontal direction. In that case, for example, as shown in FIG. 10, a pair of left and right plate molds 30 are provided, and the same is set on the outer mold 31. Similarly, pouring, solidification, removal of the plate mold 30, and pulling out of the heat resistant wire 2 are performed. Can be manufactured. In this case, the plate mold 30 forms the side surface of the cast metal material, and the outer mold 31 forms the lower surface.

The heat-resistant wire has a predetermined shape retention property and bending deformation possibility, and a thin metal wire is preferably used. The heat-resistant wire 2 can be curved (for example, wavy, spiral, etc.) or bent (bent in a plurality of directions) in addition to the linear one as in this example, and remains in this shape. The heat-resistant wire drawing hole 10 having a curved shape or a bent shape can be obtained by drawing out the heat-resistant wire while bending and deforming the casting integrated with the metal material. Since the heat-resistant wire must maintain heat resistance in the state where the molten material is poured, its melting point must be higher than the melting point of the metal material used for the molten material. It is desirable that the temperature is at least 100 ° C. or higher.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

1 Heat sink 2 Heat-resistant wire 2a End 3 Mold 4 Casting 4b Side 5 Jig 6 Jig 7 Heater 8 Cooling object 9 Release agent layer 10 Extraction hole 11 Hole 12 Molten material 13 Closure member 14 Fluid storage space 30 Plate type 31 Outer type 9 Solid material

Claims

A heat sink made of a cast metal material, having one or more heat-resistant wire drawing holes opened on the outer surface, and dissipating heat into the fluid flowing through the heat-resistant wire drawing holes.
The first aspect of the present invention, wherein the heat-resistant wire drawing hole is a single or a plurality of heat-resistant wire drawing holes that are provided in a mold of the cast product and are embedded in a metal material that solidifies with the ends exposed on the outer surface. heat sink.
The heat sink according to claim 2, wherein the heat-resistant wire has a surface coated with a release agent.
The heat sink according to claim 2 or 3, wherein the heat-resistant wire is a thin metal wire having a predetermined shape retention property and bending deformation possibility.
The cast product is provided with a bottomed hole having a cross-sectional area larger than the cross-sectional area of the drawn hole.
The heat-resistant wire drawing hole is a through hole extending from the opening on the outer surface of the casting to the opening on the inner peripheral surface of the hole, and is a hole that communicates the space inside the hole with the outer space of the casting. The heat sink according to any one of claims 1 to 4.