Cooling device

Abstract

To provide a cooling device that can reduce pressure loss without deteriorating heat dissipation performance.SOLUTION: A cooling device includes: a radiator 10 including a plurality of heat radiating members 11 having a linear base portion 12 and a plurality of convex portions 13 protruding from the base portion 12; and a case 20 that houses the radiator 10 therein and has heating elements mounted on the outside on the side where the base portion 12 is disposed. Therein, shapes of a root and a tip of the convex portion 13 are different such that a gap between one and other convex portions 13 adjacent to each other in a direction intersecting a fluid flow direction in the case 20 is larger at the tip far from the base portion than at the root close to the base portion 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cooling device.

Background Art

[0002] In recent years, as a liquid-cooling type cooling device for cooling a power device (semiconductor element) such as an IGBT (Insulated Gate Bipolar Transistor) used in a power control device mounted on an electric vehicle, a hybrid vehicle, a train, etc., a cooling device having a plurality of pin fins has been proposed. For example, the liquid-cooling type cooling device described in Patent Document 1 includes an aluminum casing and an aluminum radiator that radiates heat to a coolant flowing through a coolant flow path in the casing. The radiator includes a plurality of aluminum heat radiation members each consisting of a straight square bar-shaped base portion having a certain length, and a plurality of pin fins formed integrally with the base portion at intervals in the longitudinal direction of the base portion and protruding in the same direction as the base portion, and at least one, here two round bar-shaped aluminum connecting members for connecting and integrating all the heat radiation members. The heat radiation member is made of a press-molded product, and the base portion has a certain height in the vertical direction and a certain thickness in a direction perpendicular to the longitudinal direction and the vertical direction. The cross-sectional shape of the pin fin is square, and is formed so as to protrude upward at either one of the upper and lower end portions of the base portion, here the upper end portion. The lengths of the base portions of all the heat radiation members and the number of pin fins are equal, and all the heat radiation members are arranged at intervals in the front-rear direction with the longitudinal direction of the base portion facing the left-right direction so that all the pin fins are arranged on a plurality of first straight lines extending in the flow direction of the coolant in the coolant flow path and on a plurality of second straight lines extending in the width direction of the coolant flow path and perpendicular to the first straight lines.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] It is desirable to minimize the pressure loss of the coolant within the cooling system. However, reducing the pressure loss leads to a decrease in heat dissipation performance. The present invention aims to provide a cooling device that can reduce pressure loss without degrading heat dissipation performance. [Means for solving the problem]

[0005] The present invention, completed with this objective in mind, is a cooling device comprising: a heat sink having a linear base portion and a plurality of heat dissipation members having a plurality of protrusions projecting from the base portion; and a case that houses the heat sink inside and has a heating element mounted on the outside on the side where the base portion is located, wherein the shape of the protrusions differs between the base and the tip, such that the gap between adjacent protrusions in a direction intersecting the fluid flow direction in the case is larger at the tip further from the base portion than at the base portion closer to the base portion. Here, the shape of the cross-section of the protrusion when cut by a plane perpendicular to the direction of protrusion of the protrusion may be a quadrilateral in which the direction of the first diagonal is parallel to the direction of flow and the direction of the second diagonal is perpendicular to the direction of flow. Furthermore, the length of the first diagonal at the base is the same as the length of the second diagonal, and the length of the first diagonal at the tip may be longer than the length of the second diagonal. Furthermore, the length of the first diagonal may gradually increase from the base to the tip, and the length of the second diagonal may gradually decrease from the base to the tip. Furthermore, the lengths of the first diagonal and the second diagonal may be the same in the first region at the root end, but different in the second region at the tip end, and may gradually change between the first and second regions. Furthermore, the shape of the cross-section at the base may be square, and the shape of the cross-section at the tip may be a rhombus with the direction of the longer diagonal parallel to the direction of flow. Furthermore, the area of ​​the cross-section of the protrusion when cut by a plane perpendicular to the direction of protrusion of the protrusion may be the same at the base and the tip. [Effects of the Invention]

[0006] According to the present invention, pressure loss can be reduced without degrading heat dissipation performance. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing an example of a cooling device according to the first embodiment. [Figure 2] This is a cross-sectional view of section II-II in Figure 1. [Figure 3] This is a cross-sectional view of section III-III in Figure 2. [Figure 4] This is an example of a perspective view of a part of a heat dissipation component. [Figure 5] (a) is a diagram showing an example of a cross-sectional view of the base, and (b) is a diagram showing an example of a cross-sectional view of the tip. [Figure 6] This diagram illustrates a method for forming a heat sink by joining multiple heat dissipation components. [Figure 7] This is an example of a perspective view of a part of the heat dissipation member of a heat sink according to the second embodiment. [Modes for carrying out the invention]

[0008] The embodiments will be described in detail below with reference to the attached drawings. <First Embodiment> Figure 1 is a perspective view showing an example of a cooling device 1 according to the first embodiment. Figure 1(a) is an example of a perspective view of the cooling device 1 seen from above, and Figure 1(b) is an example of a perspective view of the inside of the case 20, which will be described later, seen from below. Figure 2 is a cross-sectional view of section II-II in Figure 1. Figure 3 is a cross-sectional view of section III-III in Figure 2. Figure 4 is an example of a perspective view of a part of the heat dissipation member 11, viewed from below.

[0009] The cooling device 1 according to the first embodiment includes a heat sink 10 and a case 20 that houses the heat sink 10. As will be described in detail below, the heat sink 10 is made up of multiple heat dissipation members 11 arranged in a short direction, each having a linear base portion 12 and a plurality of protrusions 13 that protrude from the base portion 12 and are spaced apart in the longitudinal direction of the base portion 12. In the following, the longitudinal direction of the heat dissipation member 11 may be referred to as the left-right direction, the short direction of the heat dissipation member 11 as the front-back direction, and the direction in which the protrusions 13 protrude as the up-down direction.

[0010] The cooling device 1 is a device that cools a heat-generating element P mounted on the outer surface (top surface in this embodiment) of the case 20 via a flat insulating member I, using a cooling liquid as an example of a fluid circulating inside the case 20, and a heat sink 10. The heat-generating element P can be exemplified as a power semiconductor device such as an insulated gate bipolar transistor (IGBT). Furthermore, the heat-generating element P can be exemplified as an IGBT module in which the IGBT and a control circuit for controlling the IGBT are packaged together, or as an intelligent power module in which the IGBT module and a self-protection function are packaged together.

[0011] (Case 20) The case 20 comprises a case body 21 that houses the heat sink 10 and a cover 22 that covers the opening of the case body 21. The case body 21 has a flat bottom 21a (see FIG. 2) and side portions 21b that project upward in a direction perpendicular to the bottom 21a from each end of the bottom 21a. An inflow portion 21c that communicates the inside and outside of the case 20 and allows a coolant to flow into the inside is provided at the central portion in the front - rear direction of the side portion 21b on the first side (the left side in FIG. 1) in the left - right direction. Also, an outflow portion 21d that communicates the inside and outside of the case 20 and allows the coolant to flow out to the outside is provided at the central portion in the front - rear direction of the side portion 21b on the second side (the right side in FIG. 1) in the left - right direction. The cover 22 is a flat - plate - shaped member, and its outer shape is the same as the upper - end portion of the case body 21. A heating element P is mounted on the upper surface of the cover 22 via an insulating member I. In the cooling device 1 according to this embodiment, three heating elements P are arranged side - by - side in the left - right direction at the central portion in the front - rear direction.

[0012] (Radiator 10) The base portion 12 is in the shape of a rectangular parallelepiped, and the size in the up - down direction is smaller than the size in the front - rear direction. The convex portion 13 is in the shape of a quadrangular prism and projects downward from the base portion 12 so that the column direction is the up - down direction. As shown in FIG. 3, a plurality of convex portions 13 are arranged at equal intervals, and the size between the centers of adjacent convex portions 13 in the left - right direction is set to a distance L0. Also, the plurality of convex portions 13 are arranged such that the distance L2 from the second end face 12b, which is the end face on the second side in the left - right direction of the base portion 12, to the center of the convex portion 13 arranged at the position closest to the second end face 12b is larger than the distance L1 from the first end face 12a, which is the end face on the first side in the left - right direction of the base portion 12, to the center of the convex portion 13 arranged at the position closest to the first end face 12a.

[0013] When viewed in the vertical direction, the plurality of heat dissipation members 11 are arranged such that the first end face 12a of the base portion 12 is on the first side and the second end face 12b is on the second side in a first state of the heat dissipation member 11, and the heat dissipation members 11 in a second state rotated 180 degrees at the central portion in the left-right direction and at the central point in the front-rear direction with respect to the first state are arranged alternately. In the second state, the heat dissipation member 11 is arranged such that the first end face 12a is on the second side and the second end face 12b is on the first side.

[0014] Also, among the plurality of heat dissipation members 11, the base portions 12 of adjacent heat dissipation members 11 are arranged to be in contact with each other. That is, the rear end face 12c of the base portion 12 of one heat dissipation member 11 and the front end face 12d of the base portion 12 of another heat dissipation member 11 adjacent to the one heat dissipation member 11 are arranged to be in contact with each other. Also, the positions in the left-right direction of the first end face 12a of the one heat dissipation member 11 and the positions in the left-right direction of the second end face 12b of the other heat dissipation member 11 are the same, and the positions in the left-right direction of the second end face 12b of the one heat dissipation member 11 and the positions in the left-right direction of the first end face 12a of the other heat dissipation member 11 are arranged to be the same.

[0015] The convex portions 13 are different in shape between the root portion 13b provided closer to the base portion 12 and the tip portion 13t provided farther from the base portion 12 such that the gap between the convex portions 13 adjacent to each other in a direction intersecting the left-right direction is larger at the tip portion 13t than at the root portion 13b.

[0016] More specifically, the shape of the convex portion 13 is as follows. In other words, the protrusions 13 of one heat dissipation member 11 and the protrusions 13 of another heat dissipation member 11 adjacent to the first heat dissipation member 11 are adjacent to each other in a direction that intersects with the left-right direction. For example, two protrusions 13 provided on one heat dissipation member 11 that are adjacent to each other in the left-right direction, and a protrusion 13 provided on another heat dissipation member 11 adjacent to the first heat dissipation member 11, which is located midway between the two protrusions 13 in the left-right direction, are arranged to form a triangle. It can be exemplified that this triangle is an isosceles triangle. Furthermore, it can be exemplified that this triangle is a right-angled isosceles triangle.

[0017] Figure 5(a) shows an example of a cross-sectional view of the base portion 13b, and Figure 5(b) shows an example of a cross-sectional view of the tip portion 13t. The protrusion 13 has a square cross-section at its base 13b when cut by a plane perpendicular to the vertical direction, and a rhombus cross-section at its tip 13t when cut by a plane perpendicular to the vertical direction, with the direction of the longer diagonal parallel to the left-right direction.

[0018] In other words, the shape of the cross section of the protrusion 13 when cut by a plane perpendicular to the vertical direction is a quadrilateral in which the direction of the first diagonal DL1 is parallel to the left-right direction and the direction of the second diagonal DL2 is perpendicular to the left-right direction, the length of the first diagonal DL1 at the base portion 13b is the same as the length of the second diagonal DL2, and the length of the first diagonal DL1 at the tip portion 13t is longer than the length of the second diagonal DL2.

[0019] Furthermore, the area of ​​the cross-section obtained by cutting with planes perpendicular to the vertical direction is the same at the base 13b and the tip 13t. The length of the first diagonal DL1 gradually increases from the base 13b to the tip 13t, and the length of the second diagonal DL2 gradually decreases from the base 13b to the tip 13t.

[0020] The convex portion 13, configured as described above, is press-molded integrally with the base portion 12 and then twisted relative to the base portion 12, resulting in a orientation rotated relative to the base portion 12. In the first embodiment, as shown in Figure 3, the convex portion 13 is rotated 45 degrees relative to the base portion 12. After rotating the convex portion 13 45 degrees relative to the base portion 12, the convex portion 13 is molded into the above shape by applying pressure in the front-rear direction. The shape changes gradually, with the length of the first diagonal DL1 gradually increasing from the root portion 13b to the tip portion 13t, and the length of the second diagonal DL2 gradually decreasing from the root portion 13b to the tip portion 13t. Compared to a shape that changes in steps, for example, the lifespan of the mold that applies pressure in the front-rear direction is extended.

[0021] Figure 6 is a diagram illustrating a method for forming a heat sink 10 by joining multiple heat dissipation members 11 together. As described above, the multiple heat dissipation members 11 are arranged so that the heat dissipation members 11 in the first state and the heat dissipation members 11 in the second state are alternated, and the base portions 12 are in contact with each other, with the base portions 12 being joined by laser welding.

[0022] When laser welding, laser light L is irradiated from the laser head 151 of the laser device 150 onto the left and right ends of the base portion 12, or between the first end face 12a and the protrusion 13 located closest to the first end face 12a. Then, while irradiating with laser light L, the laser head 151 is moved in the direction of the arrangement of the multiple heat dissipation members 11 (front and back direction), thereby continuously irradiating the multiple heat dissipation members 11 with laser light L. This is done for both the left and right ends of the base portion 12.

[0023] Furthermore, the laser beam L is not limited to irradiating the left and right ends of the base portion 12, or between the first end face 12a and the protrusion 13 located closest to the first end face 12a. Multiple heat dissipation members 11 may also be joined by irradiating other parts of the base portion 12, for example, between the protrusions 13.

[0024] In the heat sink 10 configured as described above, the upper surfaces of the base portions 12 of the multiple heat dissipation members 11 are arranged so as to contact the lower surface of the cover 22, and the upper surfaces of the base portions 12 and the lower surface of the cover 22 are joined together. In addition, the tip surfaces of the multiple protrusions 13 of the multiple heat dissipation members 11 are joined to the bottom portion 21a of the case body 21. Furthermore, the upper end of the case body 21 is joined to the lower surface of the cover 22. The heat dissipation members 11 and the case 20 can be exemplified as being made of aluminum. In addition, the joining can be exemplified as welding such as crimping, bonding, or brazing. When the case body 21 and the cover 22 are brazed, the case body 21 and the cover 22 can be exemplified as being formed using aluminum brazing sheets. In this case, at least the brazing material layer is located on the upper end of the case body 21 and the lower surface of the cover 22, which are opposite each other. Furthermore, the heat sink 10 does not necessarily have to have both the base portion 12 and the protrusion portion 13 joined to the case 20. It is also acceptable for either the base portion 12 or the protrusion portion 13 to be joined to the case 20.

[0025] In the cooling device 1 configured as described above, the coolant that flows into the case 20 from the inlet 21c located on the first side in the left-right direction passes through the gap between the protrusion 13 of one heat dissipation member 11 and the protrusion 13 of another heat dissipation member 11 adjacent to the first heat dissipation member 11, which is located in a direction intersecting the left-right direction, and proceeds toward the outlet 21d, from which it flows out of the case 20. Thus, in the cooling device 1, the coolant flows in the left-right direction from the inlet 21c toward the outlet 21d, so the left-right direction is the direction of coolant flow. As the coolant flows through the inside of the case 20, it cools the heat-generating element P attached to the case 20.

[0026] The cooling device 1 includes a heat sink 10 having a linear base portion 12 and a plurality of heat dissipation members 11 having a plurality of protrusions 13 projecting from the base portion 12, and a case 20 that houses the heat sink 10 and has a heat-generating element P mounted on the outside of the side where the base portion 12 is located. The protrusions 13 have different shapes at the base portion 13b and the tip portion 13t, such that the gap between adjacent protrusions 13 in a direction intersecting the flow direction of the coolant in the case 20 is larger at the tip, which is further from the base portion 12, than at the root, which is closer to the base portion 12.

[0027] In the cooling device 1 configured in this way, the gap between the protrusions 13 is larger at the tip than at the base, so the pressure loss at the base is greater than the pressure loss at the tip. Therefore, the heat dissipation performance at the base, where the heat-generating element P is attached, is higher than that at the tip. In other words, in order to reduce the pressure loss at the tip, which is the part opposite to where the heat-generating element P is attached, the protrusions 13 are configured such that the gap between the tips is larger than the gap between the bases of the protrusions 13. At the tip of the protrusions 13, the pressure loss is small, but since it is on the opposite side from where the heat-generating element P is attached, the heat dissipation performance does not decrease. As a result, the cooling device 1 can reduce pressure loss without degrading heat dissipation performance.

[0028] Furthermore, in the heat sink 10, the multiple heat dissipation members 11 are joined together by laser welding, for example, at the longitudinal ends of the base portion 12 of each heat dissipation member 11. This allows for simpler joining compared to joining by other methods. In addition, the spacing between adjacent heat dissipation members 11 can be adjusted with high precision. However, the method of joining the multiple heat dissipation members 11 is not limited to laser welding. For example, they may be joined using connecting members, as in the heat sink described in Patent Document 1.

[0029] Furthermore, since the heat sink 10 is constructed by rotating adjacent heat dissipation members 11 of the same shape by 180 degrees, the number of parts can be reduced and it can be manufactured at a lower cost compared to constructing it by arranging different members alternately. Furthermore, the shape of the base portion 13b of the protrusion 13 of the heat dissipation member 11, when viewed in the direction of protrusion, is square and inclined at 45 degrees with respect to the left-right direction. In other words, the shape of the base portion 13b of the protrusion 13, when viewed in the direction connecting the inlet portion 21c and the outlet portion 21d, is a rhombus with corners on the line in that direction. This allows the coolant flowing in from the inlet portion 21c located in the center in the front-rear direction to be directed towards both ends in the front-rear direction. As a result, both ends in the front-rear direction of the heat generating element P can be cooled in the same way as the center portion.

[0030] <Second Embodiment> Figure 7 is an example of a perspective view of a part of the heat dissipation member 51 according to the second embodiment. In the second embodiment, the heat dissipation member 51 differs from the heat dissipation member 11 in the first embodiment in that the protrusion 53, which corresponds to the protrusion 13, is different. The protrusion 53 has a root portion 53b located near the base portion 12 that extends over a first region R1 in the vertical direction, and a tip portion 53t located at the tip further from the base portion 12 that extends over a second region R2 in the vertical direction. The root portion 53b, like the root portion 13b, is a square with the same length for the first diagonal DL1 and the second diagonal DL2, and the tip portion 53t, like the tip portion 13t, is a rhombus with different lengths for the first diagonal DL1 and the second diagonal DL2. The direction of the first diagonal DL1 is parallel to the left-right direction, and the direction of the second diagonal DL2 is perpendicular to the left-right direction. The lengths of the first diagonal DL1 and the second diagonal DL2 gradually change between the first region R1 and the second region R2.

[0031] Even in the convex portion 53 configured as described above, the shape of the root portion 53b and the tip portion 53t differs such that the gap between them and other adjacent convex portions 53 in the direction intersecting the left-right direction is larger at the tip portion 53t, which is located further from the base portion 12, than at the root portion 53b, which is located closer to the base portion 12.

[0032] Therefore, in a cooling device (not shown) equipped with a heat sink (not shown) having a heat dissipation member 51 provided with protrusions 53, the gap between the protrusions 53 is larger at the tip than at the base, so the pressure loss at the base is greater than the pressure loss at the tip. Consequently, the heat dissipation performance at the base, which is the part where the heat-generating element P is attached, is higher than the heat dissipation performance at the tip. At the tip side of the protrusions 53, the pressure loss is small, but since this is the opposite side from where the heat-generating element P is attached, the heat dissipation performance does not decrease. As a result, with a cooling device (not shown) having a heat dissipation member 51, the pressure loss can be reduced without degrading the heat dissipation performance. [Explanation of symbols]

[0033] 1...Cooling device, 10...Heat sink, 11, 51...Heat dissipation member, 12...Base part, 13, 53...Protrusion part, 13b, 53b...Root part, 13t, 53t...Tip part, 20...Case, 21...Case body, 22...Cover, 151...Laser head, L...Laser beam, P...Heating element

Claims

1. A heat sink comprising a linear base portion and a plurality of heat dissipation members having a plurality of protrusions extending from the base portion, A case in which the heat sink is housed inside and a heat-generating element is attached to the outside of the side on which the base portion is located, Equipped with, The aforementioned protrusions have different shapes at their base and tip, such that the gap between them and other adjacent protrusions in a direction intersecting the fluid flow direction in the case is larger at the tip, which is further from the base, than at the base, which is closer to the base, and the cross-sectional shape when the protrusion is cut by a plane perpendicular to the direction of protrusion is rectangular. Cooling device.

2. The shape of the cross-section of the protruding portion when cut by a plane perpendicular to the direction of protrusion of the protruding portion is a quadrilateral in which the direction of the first diagonal is parallel to the direction of flow and the direction of the second diagonal is perpendicular to the direction of flow. The cooling device according to claim 1.

3. The length of the first diagonal at the base is the same as the length of the second diagonal, and the length of the first diagonal at the tip is longer than the length of the second diagonal. The cooling device according to claim 2.

4. The length of the first diagonal gradually increases from the base to the tip, and the length of the second diagonal gradually decreases from the base to the tip. The cooling device according to claim 3.

5. The lengths of the first diagonal and the second diagonal are the same in the first region at the base and different in the second region at the tip, and gradually change between the first region and the second region. The cooling device according to claim 3.

6. The cross-sectional shape at the base is square, and the cross-sectional shape at the tip is a rhombus with the direction of the longer diagonal parallel to the direction of flow. A cooling device according to any one of claims 2 to 5.

7. The area of ​​the cross-section of the aforementioned protrusion, when cut by a plane perpendicular to the direction of protrusion, is the same at the base and the tip. A cooling device according to any one of claims 1 to 6.

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