JP6864346B2 - heatsink - Google Patents

Description

The present invention relates to a heat sink and a method for manufacturing a heat sink.

Power devices are indispensable for inverter technologies such as electric vehicles, wind power generation, and home appliances. On the other hand, power devices have a limited operating temperature, so optimization of thermal design is required. Generally, a heat sink is used to dissipate heat from a power device, and heat generated from a heat source is dissipated to the outside air by the heat sink.

The conventional heat sink generally has a structure in which a plurality of plate-shaped fins or rod-shaped fins are provided on the base at intervals. However, in recent years, there has been a demand for higher efficiency of heat sinks in order to support power devices having a high heat generation density, and in order to dissipate heat more efficiently, porous metals (see, for example, Patent Documents 1 to 4). And metal fibers (see, for example, Patent Documents 5 and 6) have been studied for heat sinks.

Y. Kondo and H. Koshita, Heat transfer characteristics of porous metal fins, Proc. 2015 JSME Thermal Engineering Conference, F112, (October 2015). K. Ando, Y. Imai, H. Hirai and A. Nakayama, Heat transfer enhancement using a pin fin heat sink filled with metal foams, Transactions of the JSME, Series B, 77 (782) (2011), pp. 1958- 1967. E. Takegoshi, Y. Hirasawa, J. Matsuo and K. Okui, A study on effective thermal conductivity of porous metals, Transactions of the JSME, Series B, 58 (547) (1992), pp.879-884. S. Tzeng and T. Jeng, Convective heat transfer in porous channels with 90-deg turned flow, International Journal of Heat and Mass Transfer, 49 (2006), pp. 1452-1461. Y. Komatsu, M. Sugawara, K. Sato and T. Fujita, Thermal performance experiment for sintered aluminum fibrous heat sink, Transactions of the JSRAE, 26 (3) (2009), pp.217-224. K. Okazaki, K. Yamamoto, M. Sakagami, M. Senda and K. Inaoka, Heat transfer and pressure loss characteristics of a channel flow with fibrous aluminum layer, Transactions of the JSME, Series B, 79 (800) (2013) , pp.649-659.

Porous metals and metal fibers have a large heat transfer area, and when they are used as a heat sink, they exhibit excellent heat transfer properties. However, a heat sink using a porous metal or a metal fiber has a low effective thermal conductivity and a large pressure loss, and thus has problems in these respects.

The present invention has been made by paying attention to the above-mentioned problems, and an object of the present invention is to provide a heat sink having high heat transfer performance while suppressing a significant increase in pressure loss.

An object of the present invention is to use a base, a plurality of rod-shaped fins arranged in one direction on the base and arranged in a plurality of rows at intervals in the other direction orthogonal to the one direction, and the above-mentioned one. A plurality of horizontal members for connecting a plurality of the rod-shaped fins arranged in at least one direction and the other direction, and a plurality of horizontal members arranged in the vertical direction and in a direction orthogonal to the plurality of horizontal members. Achieved by a heat sink equipped with.

In a preferred embodiment of the heat sink according to the present invention, the plurality of horizontal members are a plurality of first horizontal members extending in one direction and connecting the plurality of rod-shaped fins aligned in the one direction. , A plurality of first horizontal members arranged in the vertical direction and the other direction, and a plurality of second horizontal members extending in the other direction and sequentially connecting the adjacent rod-shaped fins of each row arranged in the other direction. It is a frame member, and is characterized in that it is composed of a plurality of second horizontal frame members arranged in the vertical direction and in the one direction.

In a more preferred embodiment of the heat sink according to the present invention, the plurality of rod-shaped fins are arranged in a grid pattern when viewed from above, and the plurality of second horizontal members are aligned in the other direction. It is characterized in that a plurality of the rod-shaped fins are connected. In this embodiment, it is more preferable that the plurality of the first horizontal members and the plurality of the second horizontal members intersect with each other.

In a still more preferred embodiment of the heat sink according to the present invention, the plurality of rod-shaped fins are arranged in a staggered manner when viewed from above, and the plurality of first horizontal members are viewed from the one direction. The second horizontal members are arranged in a staggered manner, and the rod-shaped fins in each row arranged in the other direction are connected in a zigzag shape to form a truss with the first horizontal members. It is characterized by.

In the heat sink of the above-described embodiment, at least one of the plurality of rod-shaped fins, the plurality of first horizontal members, and the plurality of second horizontal members may further have a streamlined cross-sectional shape. preferable.

Further, in the heat sink of the above-described embodiment, the plurality of rod-shaped fins have a cross-sectional shape that gradually increases toward the base side, and the plurality of the first horizontal members and the plurality of the second horizontal members. It is more preferable that the cross-sectional shape becomes larger toward the base side.

Further, in the heat sink of the above-described embodiment, the plurality of the second horizontal members have a cross-sectional shape that gradually increases in the direction in which the outside air flows, and the plurality of the rod-shaped fins and the plurality of the first horizontal members. It is more preferable that the material has a larger cross-sectional shape in the direction in which the outside air flows.

Further, in the heat sink of the above-described embodiment, it is more preferable to use a metal containing at least one selected from the group consisting of aluminum, copper, iron and titanium as a main component as a constituent material.

Further, in the heat sink of the above-described embodiment, the porosity is more preferably 50% or more.

The object of the present invention is a method for manufacturing a heat sink having the above structure, wherein a first step of spreading the material powder constituting the heat sink to form a material powder layer and a material powder in a predetermined region of the material powder layer are provided. A second step of forming a block body by melting, solidifying, or sintering is provided, and the formation of the material powder layer by the first step and the molding of the block body by the second step are repeated, and a plurality of steps are performed. It is also achieved by the method of manufacturing a heat sink in which the heat sink is manufactured by laminating and integrating the block bodies.

In a preferred embodiment of the method for producing a heat sink according to the present invention, the material powder is characterized by containing 60% by mass or more of aluminum as a main component.

In a more preferred embodiment of the method for producing a heat sink according to the present invention, the material powder is at least one selected from the group consisting of aluminum as a main component and silicon, magnesium, copper, zinc, manganese, scandium and lithium. It is characterized by containing the above.

According to the present invention, it is possible to provide a heat sink having high heat transfer performance while suppressing a significant increase in pressure loss.

It is a perspective view of the heat sink which concerns on 1st Embodiment of this invention. It is a perspective view which shows one row of the heat sink 1 of FIG. 1 enlarged. It is explanatory drawing explaining the arrangement of the rod-shaped fins of the heat sink of FIG. It is a perspective view of the modification of the heat sink which concerns on 1st Embodiment of this invention. It is a perspective view which shows the one row of the heat sink 1 of FIG. 4 enlarged. It is a perspective view of the modification of the heat sink which concerns on 1st Embodiment of this invention. It is a perspective view which shows the one row of the heat sink 1 of FIG. 6 enlarged. It is a perspective view of the modification of the heat sink which concerns on 1st Embodiment of this invention. It is a perspective view which shows the one row of the heat sink 1 of FIG. 8 enlarged. It is a perspective view of the heat sink which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the one row of the heat sink 1 of FIG. 10 enlarged. It is explanatory drawing explaining the arrangement of the rod-shaped fins of the heat sink of FIG. It is a perspective view of the modification of the heat sink which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the one row of the heat sink 1 of FIG. 13 enlarged. It is a process drawing explaining the process of the manufacturing method of the heat sink which concerns on one Embodiment of this invention. Following FIG. 15, it is a process diagram for explaining the process of the heat sink manufacturing method. Following FIG. 16, it is a process diagram explaining the process of the manufacturing method of a heat sink. Following FIG. 17, it is a process diagram explaining the process of the manufacturing method of a heat sink. Following FIG. 18, it is a process diagram explaining the process of the manufacturing method of a heat sink. Following FIG. 19, it is a process diagram for explaining the process of the method of manufacturing a heat sink. Following FIG. 20, it is a process diagram explaining the process of the manufacturing method of a heat sink. Following FIG. 21, it is a process diagram explaining the process of the manufacturing method of a heat sink. Following FIG. 22, it is a process diagram explaining the process of the manufacturing method of a heat sink. It is a perspective view which shows the one row of the heat sink of the comparative example in an enlarged manner. It is explanatory drawing which shows the boundary condition of the numerical analysis of a heat transfer performance. It is a graph which shows the result of the numerical analysis of the heat transfer amount. It is a graph which shows the result of the numerical analysis of a pressure loss. It is a graph which shows the result of the numerical analysis of fin efficiency. It is a graph which shows the result of the numerical analysis of the effective heat transfer coefficient based on the substrate area. It is explanatory drawing which shows the experimental apparatus of heat transfer performance. It is a graph which shows the comparison result between a numerical analysis of a heat transfer amount and a pressure loss, and an experiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention relates to a heat sink having a complicated shape that is difficult to manufacture by machining or casting, and a laminated molding technique capable of manufacturing the heat sink. The heat sink of the present invention is suitably used for cooling a heating element / element in an electronic control device used in, for example, an automobile (electric vehicle), a train, a railroad vehicle, an aircraft, an aircraft engine, various industrial machines, electronic devices, electric power equipment, and the like. Will be done.

FIG. 1 shows the appearance of the heat sink 1 according to the first embodiment of the present invention, and FIG. 2 shows a part of the heat sink 1 of FIG. 1 in an enlarged manner. The heat sink 1 includes a base 2 and a fin unit 10 integrally formed on the base 2. Hereinafter, the side (Z direction) in which the fin unit 10 is attached to the base 2 will be described as the upward direction. Further, it is assumed that the outside air flows in the Y direction, and the X direction will be described as the left-right direction and the Y direction as the front-rear direction.

The base 2 is formed in a rectangular plate shape having a predetermined thickness, and the upper surface is a mounting surface for the fin unit 10 and the lower surface is a heat receiving surface. By fixing the base 2 on the heat generation source, the heat generated in the heat generation source is transferred to the fin unit 10 via the base 2. The width W, length L, and thickness t of the base 2 can be appropriately changed according to the object used for heat dissipation, and are not particularly limited.

The fin unit 10 includes a plurality of rod-shaped fins 3 provided vertically with respect to the upper surface of the base 2, a plurality of first horizontal members 4 extending in one direction (left-right direction) above the base 2, and above the base 2. It is composed of a plurality of second horizontal members 5 extending in the other direction (Y direction) orthogonal to the one direction (X direction).

The rod-shaped fins 3 form a row by arranging a plurality of rod-shaped fins 3 at intervals in one direction (left-right direction) on the base 2, and form a plurality of rows at intervals in the other direction (Y direction). And are arranged. In the present embodiment, as shown in FIG. 3, the rod-shaped fins 3 are arranged on the upper surface of the base 2 in a grid pattern (parallel arrangement) when viewed from above. That is, the adjacent rod-shaped fins 3 in each row arranged in the other direction (Y direction) when viewed from above are arranged in a row without being displaced in the one direction (X direction). In addition, "proximity" means that it is located closest. Further, in the present embodiment, as shown in FIG. 3A, the spacing P'in one direction (X direction) and the spacing P in the other direction (Y direction) are the same, and the rod-shaped fins 3 are uniformly arranged. However, as shown in FIG. 3B, the rod-shaped fins 3 are uniformly arranged with the difference P'in the one direction (X direction) and the distance P in the other direction (Y direction). May be good. Further, the rod-shaped fin 3 is formed in a columnar shape in the present embodiment. The diameter, height H, and intervals P and P'of the rod-shaped fins 3 can be appropriately changed according to the object used for heat dissipation, and are not particularly limited.

The first horizontal member 4 extends linearly in the one direction (X direction), and connects a plurality of rod-shaped fins 3 aligned in the one direction (X direction). A plurality of the first horizontal members 4 are arranged in parallel in the vertical direction and the other direction (Y direction) so as to form a grid (parallel arrangement) when viewed from the one direction (X direction), and the first horizontal member 4 is arranged in parallel in the other direction. A lattice is formed orthogonally to a plurality of rod-shaped fins 3 in each row arranged in the (Y direction). The first horizontal member 4 is formed in a columnar shape in the present embodiment. The diameter, length, and spacing of the first horizontal member 4 can be appropriately changed according to the object used for heat dissipation, and are not particularly limited. In the present embodiment, the diameter of the first horizontal member 4 is the same as the diameter of the rod-shaped fin 3.

The second horizontal member 5 extends linearly in the other direction (Y direction), and connects a plurality of rod-shaped fins 3 aligned in the other direction (Y direction). A plurality of the second horizontal members 5 are arranged in parallel in the vertical direction and the one direction (X direction) so as to form a grid (parallel arrangement) when viewed from the other direction (Y direction), and the second horizontal member 5 is arranged in parallel in the one direction. A grid is formed orthogonally to a plurality of rod-shaped fins 3 in each row arranged in the (X direction). The second horizontal member 5 is formed in a columnar shape in the present embodiment. The diameter, length, and spacing of the second horizontal member 5 can be appropriately changed according to the object used for heat dissipation, and are not particularly limited. In the present embodiment, the diameter of the second horizontal member 5 is the same as the diameter of the rod-shaped fin 3.

The plurality of second horizontal members 5 intersect with each other with the plurality of first horizontal members 4, and each of the second horizontal members 5 sequentially connects the intersections of the rod-shaped fins 3 and the first horizontal member 4. It extends in a straight line so as to. The plurality of second horizontal members 5 do not necessarily have to intersect each other with the plurality of first horizontal members 4, and are displaced in the vertical direction with respect to the plurality of first horizontal members 4. You may.

In the heat sink 1 of the first embodiment having the above configuration, the plurality of rod-shaped fins 3, the plurality of first horizontal members 4 and the plurality of second horizontal members 5 are assembled in a complicated shape such as a lattice structure. The heat transfer area of the heat sink 1 is larger than that of a conventional structure in which a plurality of plate-shaped fins or rod-shaped fins are provided at intervals. Further, although the details will be described later, since the effective heat transfer coefficient described later can be increased while suppressing a significant increase in the pressure loss of the heat sink 1, the heat sink 1 having high heat transfer performance can be obtained.

Here, in the heat sink 1 of the first embodiment described above, the rod-shaped fins 3, the first horizontal member 4 and the second horizontal member 5 are all formed in a columnar shape, but in addition to the prismatic shape, various types are formed. It can be a rod-shaped body having the cross-sectional shape of. For example, as shown in FIGS. 4 and 5, at least one of the rod-shaped fins 3, the first horizontal member 4 and the second horizontal member 5 can have a streamlined cross-sectional shape. The streamline is a slender and tapered shape as a whole with one end round and the other end pointed. As shown in FIGS. 4 and 5, at least one of the rod-shaped fins 3, the first horizontal member 4 and the second horizontal member 5 is formed in a cross-sectional line-of-sight shape, and the outside air flows in the front-rear direction (Y). In the direction), it is possible to reduce the pressure loss of the outside air passing through the heat sink 1 by setting the direction so as to taper toward the rear side.

Further, in the heat sink 1 of the first embodiment described above, the second horizontal member 5 extending in the front-rear direction (Y direction) through which the outside air flows has a constant cross-sectional shape (diameter) over the entire length in the axial direction (length direction). However, the cross-sectional shape (diameter) can be gradually increased from one end to the other end in the axial direction. For example, as shown in FIGS. 6 and 7, the second horizontal member 5 may have a small cross-sectional shape on the upstream side and a cross-sectional shape that gradually increases toward the downstream side (direction in which outside air flows). it can. As a result, in the open system usage environment (open system space), the flow rate of the outside air passing through the heat sink 1 increases, so that the effective heat transfer coefficient of the heat sink 1 can be further increased, and the heat transfer performance can be further improved. It is possible. In this case, as shown in FIGS. 6 and 7, the rod-shaped fins 3 and the first horizontal member 4 are located on the downstream side (direction in which the outside air flows) according to the cross-sectional shape of the second horizontal member 5. It is preferable to increase the cross-sectional shape (diameter) toward the direction of. Thereby, the effective heat transfer coefficient of the heat sink 1 can be further increased.

Further, in the heat sink 1 of the first embodiment described above, the rod-shaped fin 3 has a constant cross-sectional shape (diameter) over the entire length in the axial direction (height direction), but gradually increases from one end to the other end in the axial direction. The cross-sectional shape (diameter) can be increased. For example, as shown in FIGS. 8 and 9, the rod-shaped fin 3 can have a small cross-sectional shape on the upper end side and a cross-sectional shape that gradually increases toward the base side 2 (downward). As a result, the heat transferred from the heat generation source via the base 2 is satisfactorily transferred from the lower end to the upper end of the rod-shaped fins 3, so that the fin efficiency of the heat sink 1 is enhanced and the heat is efficiently dissipated on the entire surface of the rod-shaped fins 3. Is possible. As a result, the thermal conductivity of the heat sink 1 can be enhanced, and the heat transfer performance can be further improved. In this case, as shown in FIGS. 8 and 9, the first horizontal member 4 and the second horizontal member 5 are moved toward the base 2 side (downward) according to the cross-sectional shape of the rod-shaped fin 3. It is preferable to increase the cross-sectional shape (diameter) toward the end. Thereby, the fin efficiency of the heat sink 1 can be further increased.

Further, in the heat sink 1 of the first embodiment described above, it is also possible to form the heat sink by omitting either one of the first horizontal member 4 and the second horizontal member 5.

Next, FIG. 10 shows the appearance of the heat sink 1 according to the second embodiment of the present invention, and FIG. 11 shows a part of the heat sink 1 of FIG. 10 in an enlarged manner. The heat sink 1 of the second embodiment also includes a base 2 and a fin unit 10 integrally formed on the base 2. Since the base 2 has the same configuration as the base 2 of the heat sink 1 of the first embodiment, the description thereof will be omitted here.

The fin unit 10 includes a plurality of rod-shaped fins 3 provided vertically with respect to the upper surface of the base 2, a plurality of first horizontal members 4 extending in one direction (left-right direction) above the base 2, and a base 2. It is composed of a plurality of second horizontal members 5 extending upward in the other direction (Y direction).

The rod-shaped fins 3 form a row by arranging a plurality of rod-shaped fins 3 at intervals in one direction (left-right direction) on the base 2, and form a plurality of rows at intervals in the other direction (Y direction). And are arranged. In the present embodiment, the rod-shaped fins 3 are arranged on the upper surface of the base 2 so as to be staggered (staggered) when viewed from above. That is, a state in which adjacent rod-shaped fins 3 in each row arranged in the other direction (Y direction) when viewed from above are displaced in the one direction (X direction), for example, as shown in FIG. 12, the one direction ( The rod-shaped fins 3 in the adjacent row are arranged in a staggered state so as to be located at half the distance between the rod-shaped fins 3 adjacent to each other in the X direction). In addition, "proximity" means that it is located closest. The staggered arrangement includes a so-called 45-degree staggered arrangement (connecting the centers of the rod-shaped fins 3 with a line draws an isosceles triangle) and a 60-degree staggered arrangement (connecting the centers of the rod-shaped fins 3 with a line creates an equilateral triangle). Draw), etc., but are not particularly limited. Further, the rod-shaped fin 3 is formed in a columnar shape in the present embodiment. The diameter, height, and spacing of the rod-shaped fins 3 can be appropriately changed according to the object used for heat dissipation, and are not particularly limited.

The first horizontal member 4 extends linearly in the one direction (X direction), and connects a plurality of rod-shaped fins 3 aligned in the one direction (X direction). A plurality of the first horizontal members 4 are arranged in parallel in the vertical direction and the other direction (Y direction) so as to form a staggered shape (staggered arrangement) when viewed from the one direction (X direction). A lattice is formed orthogonally to a plurality of rod-shaped fins 3 in each row arranged in the (Y direction). The first horizontal member 4 is formed in a columnar shape in the present embodiment. The diameter, length, and spacing of the first horizontal member 4 can be appropriately changed according to the object used for heat dissipation, and are not particularly limited. In the present embodiment, the diameter of the first horizontal member 4 is the same as the diameter of the rod-shaped fin 3.

The second horizontal member 5 extends in a zigzag shape in the other direction (Y direction), and extends diagonally while alternately turning the adjacent rod-shaped fins 3 in each row arranged in the other direction (Y direction). By sequentially connecting them, the plurality of first horizontal members and trusses are formed. Specifically, the second horizontal member 5 extends so as to sequentially connect the intersections of the adjacent rod-shaped fins 3 in each row arranged in the other direction (Y direction) with the first horizontal member 4. At each intersection of the rod-shaped fin 3 with the first horizontal member 4, the second horizontal member 5 is radially focused from each of the two adjacent upper and lower intersections (four in total) in the front row. , The second horizontal member 5 radiates radially toward the intersections of two adjacent upper and lower parts (four in total) in the rear row. As a result, the plurality of second horizontal members 5 extend in the other direction (Y direction) and are adjacent to each other in the one direction (X direction), and the first horizontal members 4 in each row. A truss is formed by assembling multiple triangles with.

The second horizontal member 5 is formed in a columnar shape in the present embodiment. The diameter, length, and spacing of the second horizontal member 5 can be appropriately changed according to the object used for heat dissipation, and are not particularly limited. In the present embodiment, the diameter of the second horizontal member 5 is the same as the diameter of the rod-shaped fin 3.

In the heat sink 1 of the second embodiment described above, similarly to the heat sink 1 of the first embodiment, the plurality of rod-shaped fins 3, the plurality of first horizontal members 4 and the plurality of second horizontal members 5 have a truss structure. Because it is assembled in a complicated shape, the heat transfer area of the heat sink 1 is larger than that of the conventional structure in which a plurality of plate-shaped fins and rod-shaped fins are provided at intervals, and the outside air flows so as to bypass. High heat transfer characteristics. Further, as will be described in detail later, since the effective heat transfer coefficient can be increased while suppressing a significant increase in the pressure loss of the heat sink 1, the heat sink 1 having high heat transfer performance can be obtained.

In the heat sink 1 of the second embodiment described above, the rod-shaped fins 3, the first horizontal member 4 and the second horizontal member 5 are all formed in a columnar shape, but similarly to the first embodiment, In addition to the prismatic shape, it can be a rod-shaped body having various cross-sectional shapes. For example, although not shown, at least one of the rod-shaped fins 3, the first horizontal member 4 and the second horizontal member 5 is formed in a cross-sectional line-of-sight shape, and the outside air flows in the front-rear direction (Y direction). By setting the direction so as to taper toward the rear side, it is possible to reduce the pressure loss of the outside air passing through the heat sink 1.

Further, also in the heat sink 2 of the second embodiment described above, the second horizontal member 5 extending in the front-rear direction (Y direction) through which the outside air flows has a constant cross-sectional shape (diameter) over the entire length in the axial direction (length direction). However, as in the first embodiment, the cross-sectional shape (diameter) can be gradually increased from one end to the other end in the axial direction. For example, although not shown, the second horizontal member 5 can have a small cross-sectional shape on the upstream side and a cross-sectional shape that gradually increases toward the downstream side (direction in which the outside air flows). As a result, in the open system usage environment (open system space), the flow rate of the outside air passing through the heat sink 1 increases, so that the effective heat transfer coefficient of the heat sink 1 can be further increased, and the heat transfer performance can be further improved. It is possible. In this case, the rod-shaped fins 3 and the first horizontal member 4 have a cross-sectional shape (diameter) toward the downstream side (direction in which the outside air flows) according to the cross-sectional shape of the second horizontal member 5. It is preferable to increase. Thereby, the effective heat transfer coefficient of the heat sink 1 can be further increased.

Further, also in the heat sink 1 of the second embodiment described above, the rod-shaped fin 3 has a constant cross-sectional shape (diameter) over the entire length in the axial direction (height direction), but is directed from one end to the other end in the axial direction. The cross-sectional shape (diameter) can be gradually increased. For example, as shown in FIGS. 13 and 14, the rod-shaped fin 3 can have a small cross-sectional shape on the upper end side and a cross-sectional shape that gradually increases toward the base side 2 (downward). As a result, the heat transferred from the heat generation source via the base 2 is satisfactorily transferred from the lower end to the upper end of the rod-shaped fins 3, so that the fin efficiency of the heat sink 1 is enhanced and the heat is efficiently dissipated on the entire surface of the rod-shaped fins 3. Is possible. As a result, the thermal conductivity of the heat sink 1 can be enhanced, and the heat transfer performance can be further improved. In this case, as shown in FIGS. 13 and 14, the first horizontal member 4 and the second horizontal member 5 are moved to the base 2 side (downward) according to the cross-sectional shape of the rod-shaped fin 3. It is preferable to increase the cross-sectional shape (diameter) toward the end. Thereby, the fin efficiency of the heat sink 1 can be further increased.

Further, in the heat sink 1 of the second embodiment described above, it is possible to form the heat sink by omitting either one of the first horizontal member 4 and the rod-shaped fin 3, and further omitting both of them to form the second horizontal member. It is also possible to form a heat sink with just one.

The heat sink 1 of the first embodiment and the second embodiment described above preferably has a porosity ε of 50% or more and 95% or less, preferably 60% or more and 95% or less, in consideration of heat transferability and pressure loss. More preferably. Further, when it is desired to further improve the heat transfer property of the heat sink 1, the porosity ε is preferably 60% to 80%, and when it is desired to further reduce the pressure loss of the heat sink 1, the porosity ε is 80. It is preferably% to 95%, more preferably 88% to 95%.

The porosity ε of the heat sink 1 is the ratio of the porosity in the virtual space including the fin unit 10, and is represented by ε (%) = {1- (V / V')} × 100. Note that V is the volume of the fin unit 10, and V'is the volume of the virtual space (maximum width W x length L x height H of the fin unit 10).

Next, the method of manufacturing the heat sink 1 of the first embodiment and the second embodiment described above will be described with reference to FIGS. 15 to 23. In the following description, the manufacturing method is described by taking the heat sink 1 of the form shown in FIG. 1 as an example, but each step of the manufacturing method is the same regardless of the heat sink of any form.

The method for manufacturing the heat insulating material 1 according to the present invention includes a first step of laying material powder, which is a constituent material of the heat insulating material 1, on, for example, a base material 102 to form a material powder layer M having a predetermined thickness, and a material powder layer M. A second step of forming a block body B by melting, solidifying, or sintering a material powder in a predetermined region is provided, and a new material powder layer M is formed on the block body B and the block body B is formed. By repeating the above steps, the plurality of block bodies B are laminated and integrated in the vertical direction to manufacture the heat sink 1.

The apparatus for manufacturing the heat sink 1 includes, for example, a flat base material 102 inside a chamber 100 surrounded by the periphery. Material powder is supplied on the base material 102. Examples of the material of the base material 102 include steel such as iron, carbon steel, alloy steel, and stainless steel, general-purpose metal materials such as aluminum, titanium, and copper, heat-resistant plastic materials such as glass and polyimide, and ceramic materials. However, in particular, metal materials having high heat resistance, heat capacity, thermal conductivity, and corrosion resistance such as aluminum, titanium, copper, iron, steel, and stainless steel can be preferably used. Even if a heating device such as a heater (not shown) and a cooling device such as a water-cooled heat sink or a Peltier element (not shown) are connected to the base material 102 as necessary to constantly heat or cool the base material 102. Good. Further, it is preferable that the surface of the base material 102 is roughened by a known method such as blasting in order to improve the bondability with the heat sink 1 to be shaped. When a material that does not require the base material 102 is used, the base material 102 may not be used. Further, a heating element / element or the like to be radiated may be installed on the base material 102, and the material powder may be spread on the heating element / element to integrally form the heat sink 1. Further, the base material 102 may be used as it is as the base 2 of the heat sink 1, and only the fin unit 10 may be formed on the base material 102.

Inside the chamber 100, a width plate-shaped squeegee 103 capable of reciprocating in the chamber 100 in the horizontal direction is provided above the base material 102. By sliding the squeegee 103 above the surface of the base material 102 by a predetermined height, the material powder supplied on the base material 102 is leveled, and the squeegee 103 is a flat material powder having a substantially constant overall thickness. A layer (material powder layer M) is formed.

Inside the chamber 100, a stage 101 capable of reciprocating in the vertical direction in the chamber 100 is provided. The base material 102 is mounted on the stage 101, and the vertical position of the base material 102 can be adjusted by moving the stage 101 up and down. By adjusting the vertical position of the base material 102, the thickness of the material powder layer M can be appropriately changed. The thickness of the material powder layer M is preferably thin in order to improve the dimensional accuracy of the heat sink 1 to be manufactured.

Further, the manufacturing apparatus includes a laser beam scanning apparatus 104 that irradiates the material powder layer M with the laser beam. When the material powder layer M is irradiated with laser light, the material powder in the irradiated portion is heated and melted. By quenching and solidifying this, the material powder of the irradiated portion is formed into the block body B. Although not shown, the laser light scanning device 104 has a laser light source that emits laser light and an optical device such as a galvano mirror, and the laser light is emitted by a galvano mirror or the like to an arbitrary region on the material powder layer M. It is possible to scan with a predetermined pattern shape. Therefore, since only a specific region of the material powder layer M can be selected and the material powder can be locally heated by the laser beam, only the material powder of the portion irradiated with the laser beam is solidified to form a block body B having a desired shape and size. Can be modeled. As the laser beam emitted from the laser light source, various lasers such as a fiber laser, a carbon dioxide gas laser, a YAG laser, a semiconductor laser, a green laser, and a UV laser can be used.

In the present embodiment, the powder bed fusion bonding method is used as a method for melting and solidifying the material powder, and laser light is used as a means for solidifying the material powder. The present invention is not limited, and for example, an electron beam or plasma may be used. Further, as a method for solidifying the material powder, a 3D printing method (additional manufacturing method) other than the powder bed fusion bonding method may be used, and for example, a directed energy deposition method can be used. Further, cutting or laser trimming may be performed during modeling, or surface modification may be performed by laser, electron beam, chemical etching, or physical etching during or after modeling.

Further, although not shown, the manufacturing apparatus includes a gas tank that supplies atmospheric gas to the chamber 100. By filling the inside of the chamber 100 with the atmospheric gas, oxidation of the material powder layer M and the block body B is prevented. Examples of the atmospheric gas include nitrogen gas, argon gas, and helium gas. Further, a reducing gas may be used instead of the atmospheric gas. Further, in order to prevent oxidation of the material powder layer M and the block body B, the inside of the chamber 100 may be depressurized by a vacuum pump or the like.

In the manufacturing apparatus having the above-described configuration, first, as shown in FIG. 15, the material powder is supplied onto the base material 102 from the material powder supply unit (not shown) for storing the material powder, and then the squeegee 103 is moved in the horizontal direction (not shown). By moving in the direction of the arrow), the material powder is spread on the base material 102 to form the material powder layer M (first step). At this time, by adjusting the vertical position of the base material 102, the thickness of the material powder layer M can be set to a desired thickness.

Next, as shown in FIG. 16, the laser light scanning device 104 irradiates an arbitrary region on the surface of the material powder layer M with laser light to heat the material powder in the irradiated portion. As a result, the material powder of the laser beam irradiated portion is melted and solidified, and as shown in FIG. 17, the block body B is formed by irradiating the laser beam along a desired scanning path (second step).

The block body B is modeled based on, for example, slice data of STL data converted from three-dimensional shape data by three-dimensional CAD of the heat sink 1. The slice data is contour shape data of each cross section obtained by dividing the three-dimensional shape data of the heat sink 1 into a plurality of upper and lower layers at an equal pitch, and the base material 102 is moved up and down based on the slice data, and a plurality of slice data are stacked in the vertical direction. By irradiating each material powder layer M with a laser beam in a predetermined region, the material powder is locally melted and solidified, and a block body B having a desired shape is formed.

Then, as shown in FIG. 18, the squeegee 103 is moved in the horizontal direction on the previously formed block body B and the remaining material powder layer M to supply new material powder from the desired thickness. A new material powder layer M is formed (first step).

Then, similarly, the surface of the new material powder layer M is scanned with the laser beam to irradiate the desired range of the material powder layer M with the laser beam. As a result, as shown in FIGS. 19 and 20, the material powder of the irradiated portion is locally heated, and the material powder is melted and solidified to form a new block body B (second step). When the material powder is melted and solidified to form the block body B, it is joined to the previously formed lower layer block body B, so that the newly formed block body B is integrated with the lower layer block body B. Will be transformed into.

Then, as shown in FIGS. 21 and 22, the first step and the second step described above are repeated to stack the block bodies B, and when the number of layers of the block body B reaches a predetermined number of layers, the number of layers of the block body B reaches a predetermined number. As shown in FIG. 23, a heat sink 1 having a desired three-dimensional shape can be obtained.

In the second step, the irradiation conditions when irradiating the material powder layer M with the laser beam, that is, the output of the laser beam, the scanning speed, the scanning pitch, etc., are within the range of 1000 W or less if the output is, for example. The scanning speed can be adjusted appropriately within the range of 7000 mm / s or less, and the scanning pitch can be adjusted within the range of 0.30 mm or less. By appropriately adjusting the scanning pitch and the like according to the type and particle size of the material powder, the heat sink 1 made of a dense constituent member with few defects can be manufactured.

Next, the material powder which is the constituent material of the heat sink 1 described above will be described.

The material powder corresponds to toner and ink in a normal two-dimensional printer. The material powder is a metal powder in the present embodiment, and among them, contains at least one selected from the group consisting of aluminum (Al), copper (Cu), iron (Fe) and titanium (Ti) as a main component. It is a metal powder. The metal powder may be an alloy powder, a composite powder, or a mixed powder containing other materials such as metal, carbon, ceramics, and resin as other components in addition to the main component.

When aluminum (Al) is contained as a main component, the material powder contains 60% by mass or more of aluminum (Al), and other components include silicon (Si), magnesium (Mg), copper (Cu), and zinc. (Zn), Iron (Fe), Manganese (Mn), Lithium (Li), Nickel (Ni), Titanium (Ti), Chromium (Cr), Calcium (Ca), Zirconium (Zr), Sodium (Na), Strontium (Sr), antimony (Sb), beryllium (Be), phosphorus (P), vanadium (V), tin (Sn), lead (Pb), bismuth (Bi), cobalt (Co), silver (Ag), gallium One or more of (Ga), scandium (Sc), boron (B), oxygen (O) and the like can be mentioned, but it is preferable that silicon (Si) is contained as the second component, and magnesium is further contained. (Mg) can be preferably contained as the third component. These components may be intentionally added at the time of manufacture, or may be unavoidably mixed as impurities.

When copper (Cu) is contained as a main component, the material powder contains 50% by mass or more of copper (Cu), and other components include chromium (Cr), zinc (Zn), tin (Sn), and beryllium. (Be), silver (Ag), nickel (Ni), aluminum (Al), zirconium (Zr), silicon (Si), cobalt (Co), iron (Fe), magnesium (Mg), titanium (Ti), tellurium One or more of (Te), phosphorus (P), carbon (C), oxygen (O) and the like can be mentioned. These components may be intentionally added at the time of manufacture, or may be unavoidably mixed as impurities.

When iron (Fe) is contained as a main component, the material powder contains 60% by mass or more of iron (Fe), and other components include carbon (C), silicon (Si), manganese (Mn), and nickel. (Ni), Chromium (Cr), Cobalt (Co), Molybdenum (Mo), Tungsten (W), Titanium (Ti), Aluminum (Al), Vanadium (V), Copper (Cu), Nitrogen (N), Phosphorus One or more of (P), silicon (S), boron (B), oxygen (O) and the like can be mentioned. These components may be intentionally added at the time of manufacture, or may be unavoidably mixed as impurities.

When titanium (Ti) is contained as a main component, the material powder contains 70% by mass or more of titanium (Ti), and other components include aluminum (Al), vanadium (V), niobium (Nb), and tin. (Sn), molybdenum (Mo), titanium (Ta), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), silicon (Si), zirconium One or more of (Zr), hafnium (Hf), palladium (Pd), carbon (C), nitrogen (N), oxygen (O), hydrogen (H) and the like can be mentioned. These components may be intentionally added at the time of manufacture, or may be unavoidably mixed as impurities.

Further, examples of material powders other than these systems include cobalt (Co) -based, nickel (Ni) -based, molybdenum (Mo) -based, zirconium (Zr) -based, and tungsten (W-based).

The material powder is not necessarily limited to a metal powder containing a metal as a main component (including an alloy powder, a composite powder or a mixed powder), and may contain ceramics or a resin as a main component. Further, it may be a composite powder or a mixed powder containing other materials as other components other than ceramics and resins.

The particle size of the above-mentioned material powder is appropriately adjusted according to powder production conditions, classification, sieving and the like. The average particle size of the material powder is not particularly limited and can be adjusted according to the height of the material powder layer M when the heat sink 1 is manufactured, for example, 100 μm to 200 μm, and further. Can be 50 μm to 100 μm, and further can be 5 μm to 50 μm. The particle shape of the material powder is not particularly limited, and may be substantially spherical or any other shape.

The above-mentioned material powder can be produced by, for example, a gas atomizing method or a water atomizing method, but in addition, a mechanical process such as a rotating electrode method, a centrifugal atomizing method, a melt spinning method, or a mechanical alloying method, or an oxide reduction method. It can also be produced by a chemical process such as an ion reaction method.

Although the embodiments of the present invention have been described in detail above, the above-described embodiments are exemplary in all respects and are not restrictive, and thus the present invention is not limited to the above-described embodiments. The technical scope of the present invention is defined by the scope of claims and includes all modifications within the meaning and scope equivalent to the description of the scope of claims. Various changes can be made as long as they do not deviate from the purpose.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

As Examples 1 to 6, FIG. 1 (Cube) and FIG. 4 (Cube-Td) were formed by laminated molding using an aluminum alloy powder (Al—Si—Mg alloy powder) having an average particle size of about 25 μm as the material powder. , FIG. 6 (Cube-G), FIG. 8 (Cube-C), FIG. 10 (Truss) and FIG. 13 (Truss-C) are manufactured. Further, as a comparative example, as shown in FIG. 24 (Pin), rod-shaped fins 111 are spaced on the base 110 by laminated molding using the same aluminum alloy powder (Al—Si—Mg alloy powder) as the material powder. A heat sink having a structure provided in a plurality of spaces was manufactured. The aluminum alloy powder (Al—Si—Mg alloy powder) was produced by the gas atomization method. For additive manufacturing, a metal powder additive manufacturing device (EOSINT M280 manufactured by EOS) was used.

The conditions for irradiating the aluminum alloy powder with laser light by the laser light scanning device at the time of laminated molding are as follows.
-Laser type: Yb fiber laser-Laser output: 400 W or less-Scanning speed: 200 mm / s to 3000 mm / s
-Scanning pitch: 0.08 mm to 0.18 mm
-Laminating pitch: 0.02 mm to 0.10 mm
-Base material: Aluminum alloy (A5083)
・ Atmosphere: Argon gas atmosphere

The dimensions of the heat sinks of Examples 1 to 6 and Comparative Examples are as shown in Table 1 below. In Examples 1 to 6 and Comparative Examples, the distance P'in the X direction of the rod-shaped fins is 5 mm, and the distance P in the Y direction of the rod-shaped fins is compared with Examples 1, 2, 4 to 6. In the example, it is set to 5 mm, and in Example 3, it is set to 1.5 mm to 7 mm, and the rod-shaped fins and the first horizontal frame are set so that ^{the surface area of each fin unit is substantially constant (two levels of about 0.0039 m 2} and 0.0027 m ^2). The diameter of the material and the second horizontal member was adjusted. In addition, for each of Examples 1 to 6 and Comparative Examples, examples having a high porosity in which the diameters of the rod-shaped fins, the first horizontal member and the second horizontal member were halved were also examined. In the comparative example, in order to make the length of one side of the prism cross section the same as the diameter of Example 1 and the surface area equal to that of Examples 1 to 6, the length L of the base in the Y direction is increased (0). .05m → 0.07m), the base area was increased.

The results of numerical analysis of the heat transfer performance of Examples 1 to 6 and Comparative Examples are shown below. The unstructured grid thermo-fluid analysis software SCRYU / Tetra (manufactured by Software Cradle) was used for the numerical analysis of the heat transfer performance. For the turbulence model, the AKNk-ε model, which is a linear low Reynolds number type turbulence model that can reproduce strong viscous stress action and turbulence damping action in the region near the wall, is used, and the total number of lattices in fluid and solid is about 4 million. I made a point. The analysis conditions and boundary conditions are shown in FIG. 25 and Table 2. The effect of buoyancy due to changes in air temperature is not taken into consideration. In the numerical analysis, the heat transfer performance of each heat sink is not the total width W (= 50 mm) of the heat sink, but a column as shown in FIGS. 2, 5, 7, 7, 9, 11, 14 and the like. The width W'is set to 5 mm and modeled in a row for calculation.

The heat transfer amount Q and the pressure loss Δp of Examples 1 to 6 and Comparative Examples are shown in FIGS. 26 and 27, respectively. In each figure, when (a) is a low porosity, (b) is a high porosity. From FIG. 26, it can be seen that the higher the inlet wind speed, the larger the heat transfer amount Q in each example. Further, in (a) low porosity, the heat transfer amount Q of Example 6 (Truss-C) was the largest, followed by Example 5 (Truss) and Example 3 (Cube-G), and all of Examples 1 It was found that ~ 6 was larger than the comparative example (Pin). On the other hand, even in (b) high porosity, the heat transfer amount Q of Example 6 (Truss-C) was the largest, followed by Example 6 (Cube-C), Example 5 (Truss), and Example 3 (Cube-). G) is large. In the comparison with the comparative example (Pin), since the surface area of the fin unit was made substantially constant in each of Examples 1 to 6 and Comparative Example, it was transmitted in each of Examples 1 to 5 other than Example 6 (Truss-C). Although the calorific value Q is smaller than that of the comparative example, when the base area of the comparative example is adjusted to the base area of each of Examples 1 to 6, the heat transfer amount Q is expected to be about 5/7. Then, it can be seen that the heat transfer amount Q is larger than that of the comparative example (Pin) in all the examples 1 to 6. As described above, it was confirmed that the heat transfer performance of each of Examples 1 to 6 was higher than that of Comparative Example (Pin).

Further, from FIG. 27, the higher the inlet wind velocity, the larger the pressure loss Δp, and the pressure loss Δp is larger in each of Examples 1 to 6 as compared with Comparative Example (Pin), but in Example 1 (Cube), In Example 2 (Cube-Td) and Example 4 (Cube-C), a significant increase in pressure loss Δp can be suppressed, and in Example 2 (Cube-Td), the pressure loss Δp is similar to that of Comparative Example (Pin). It was confirmed that it could be suppressed to.

Next, the results of examining the fin efficiency η of Examples 1 to 6 and Comparative Examples are shown in FIG. 28. From FIG. 28, both (a) low porosity and (b) high porosity have the highest fin efficiency η in Comparative Example (Pin), but in Examples 1 to 4, a significant decrease in fin efficiency η can be suppressed. In Example 4 (Cube-C), the fin efficiency η can be set to be close to that of Comparative Example (Pin).

Finally, FIG. 29 shows the relationship between the effective heat transfer coefficient h based on the base area of Examples 1 to 6 and the comparative example and the pressure loss. Note that the effective heat transfer coefficient h is calculated by _{h = q / (T w -T} in), q is expressed by q = Q / (W'× L ). (A) With a low void ratio, good effective thermal conductivity was obtained for all of Examples 1, 2, 4 to 6 other than Example 3 (Cube-G) with respect to pressure loss, and in particular, Examples. The effective thermal conductivity of 6 (Truss-C) is the highest, and the effective thermal conductivity of Example 2 (Cube-Td), Example 5 (Truss), and Example 6 (Truss-C) is also Comparative Example (Pin). ) Was found to be higher. This is because, as shown in FIGS. 25 and 26, the pressure loss was suppressed in Example 2 (Cube-Td) without lowering the heat transfer performance, and in Example 5 (Truss) and Example 6. Although the pressure loss of (Truss-C) is large, it is considered that the reason is that the high heat transfer characteristic peculiar to the three-dimensional staggered arrangement was obtained. On the other hand, in (b) high void ratio, good effective heat transfer coefficient was obtained in each of Examples 1 to 6 with respect to pressure loss, and in particular, the effective thermal conductivity of Example 6 (Truss-C) was high. It was found that the effective thermal conductivity was the highest in Example 4 (Cube-C) and Example 6 (Truss-C) as well as in Comparative Example (Pin). The reason for Example 4 (Cube-C) is considered to be that the fin efficiency of Example 4 (Cube-C) is high, as shown in FIG. 28. Further, it was found that in Example 3 (Cube-G), the effective heat transfer coefficient with respect to the pressure loss was improved in the case of (a) low porosity and (b) high porosity. In Example 3 (Cube-G), the rod-shaped fins, the first horizontal member, and the second horizontal member become thicker toward the downstream side with respect to the airflow direction (Y direction). When used in the above-mentioned non-open system space, it is considered that the effective heat transfer coefficient is greatly reduced due to the influence of pressure loss, but when used in the open system space, the static pressure in the heat sink is upstream and downstream. That is, since the static pressure is low on the upstream side and high on the downstream side, the flow rate is large on the upstream side, and the vector changes in the direction perpendicular to the flow toward the downstream side. Therefore, it is assumed that the flow rate in the heat sink becomes relatively large and the effective heat transfer coefficient is increased, so that the amount of heat transfer is considered to be large.

As described above, according to the present invention, it has been confirmed that a heat sink having high heat transfer performance can be provided while suppressing a significant increase in pressure loss.

Finally, an aluminum alloy powder (Al-Si-Mg alloy powder) having an average particle size of about 25 μm was used as the material powder, and the width was 50 mm by laminating with a material powder laminating molding device (EOSINT M280 manufactured by EOS). A heat sink having each structure shown in FIGS. 1 (Cube) and 10 (Truss) having dimensions of 50 mm in length and 30 mm in height was manufactured. The results of experiments on the heat transfer performance of each heat sink of Cube and Truss with an experimental device (shown in FIG. 30) are shown in FIG. 31. The experiment was carried out in a non-open system space where the room temperature was constant at 20 ° C. The air sucked by the blower exchanges heat with the heat sink in the test section and is released to the atmosphere. The flow rate of the airflow was measured at the outlet of the non-open system space and converted into the wind speed, and the wind speed was also measured at the entrance of the non-open system space for confirmation. For the control of the rubber heater, the input power was adjusted so that the temperature of the bottom surface of the base of the heat sink was 373 K (100 ° C.), and the result was evaluated assuming that the power at that time was equal to the heat transfer amount.

FIG. 31 is a graph comparing the above-mentioned analysis results and experimental results with respect to the heat transfer amount and pressure loss of each heat sink of Cube and Truss. According to FIG. 31, the analysis value and the experimental value are almost the same, and it is confirmed that the analysis result is valid.

1 Heat sink 2 Base 3 Rod-shaped fin 4 1st horizontal member 5 2nd horizontal member

Claims (8)

With the base
A plurality of rod-shaped fins arranged in one direction on the base and arranged in a plurality of rows at intervals in the other direction which is orthogonal to the one direction and in which the outside air flows.
A plurality of horizontal members for connecting a plurality of the rod-shaped fins arranged in at least one of the one direction and the other direction, and a plurality of horizontal members arranged in the vertical direction and in a direction orthogonal to the rod-shaped fins. and, with a,
The plurality of the horizontal members
A plurality of first horizontal members extending in one direction and connecting a plurality of the rod-shaped fins aligned in the same direction, and a plurality of first horizontal members arranged in the vertical direction and the other direction. ,
A plurality of second horizontal members extending in the other direction and sequentially connecting the adjacent rod-shaped fins in each row arranged in the other direction, and a plurality of second members arranged in the vertical direction and in the one direction. It is composed of horizontal members and
The plurality of second horizontal members are heat sinks having a cross-sectional shape that gradually increases in the other direction through which outside air flows. The plurality of rod-shaped fins are arranged in a grid pattern when viewed from above.
The heat sink according to claim 1 , wherein the plurality of second horizontal members are connected to the plurality of rod-shaped fins aligned in the other direction. The heat sink according to claim 2 , wherein the plurality of the first horizontal members and the plurality of the second horizontal members intersect with each other. The plurality of rod-shaped fins are arranged in a staggered pattern when viewed from above, and the plurality of first horizontal members are arranged in a staggered pattern when viewed from the one direction.
The heat sink according to claim 1 , wherein the plurality of second horizontal members are formed by connecting the rod-shaped fins in each row arranged in the other direction in a zigzag shape to form a truss with the plurality of first horizontal members. The heat sink according to any one of claims 1 to 4 , wherein at least one of the plurality of rod-shaped fins, the plurality of first horizontal members, and the plurality of second horizontal members has a streamlined cross-sectional shape. .. The plurality of rod-shaped fins have a cross-sectional shape that gradually increases toward the base side.
The heat sink according to any one of claims 1 to 5 , wherein the plurality of the first horizontal members and the plurality of the second horizontal members have a larger cross-sectional shape toward the base side. The heat sink according to any one of claims 1 to 6 , wherein the plurality of rod-shaped fins and the plurality of first horizontal members have a larger cross-sectional shape toward the other direction in which outside air flows. The heat sink according to any one of claims 1 to 7 , wherein the porosity is 50% or more.

Images