Cooler

Abstract

A cooler (2) is provided with a base plate (20) having a first surface (20a) to which a heating element is attached and a second surface (20b) that is a surface opposite to the first surface (20a). When a direction parallel to a direction from the first surface (20a) toward the second surface (20b) is defined as a first direction, a direction intersecting the first direction is defined as a second direction, and a direction intersecting the first direction and the second direction is defined as a third direction, the cooler (2) is provided with: heat transfer blocks (30) provided on the second surface (20b) and extending in the first direction; heat pipes (40) having an evaporation portion (40a) that is inserted into the heat transfer block (30) and extending from the heat transfer block (30) toward the side opposite to the base plate (20); fins (50) attached to the heat pipes (40); and a cooling fan (60) that generates wind flowing in the second direction and guides the wind toward the heat transfer blocks (30), the heat pipes (40), and the fins (50).

Description

Cooler

[0001] The present disclosure relates to a cooler for cooling a semiconductor device.

[0002] Semiconductor devices are required to be miniaturized and have high output. A semiconductor device includes heat-generating bodies such as power devices, semiconductor elements, and capacitors. Since a heat-generating body generates heat when driven, a cooler is necessary for a semiconductor device.

[0003] As a conventional cooler, the cooler disclosed in Patent Document 1 is known. The cooler disclosed in Patent Document 1 includes a base plate, a heat pipe, and fins. The base plate is a rectangular plate-shaped member, and a heat-generating body is attached to the surface of the base plate. A heat pipe is disposed on the back surface of the base plate, which is the surface opposite to the front surface. The heat pipe is bent a plurality of times at right angles and has an evaporation portion parallel to the back surface of the base plate. The evaporation portion is a part that receives heat generated from the heat-generating body via the base plate. The fins are disposed on the heat pipe. In the cooler disclosed in Patent Document 1, the heat of the heat-generating body is diffused by the base plate and the heat pipe, and the diffused heat is radiated into the air through the fins disposed on the heat pipe, thereby cooling the heat-generating body.

[0004] Japanese Patent Laid-Open No. 2002-076224

[0005] However, in the technology disclosed in Patent Document 1, since the heat pipe is directly installed on the base plate such that the back surface of the base plate and the evaporation portion of the heat pipe are parallel to each other, the heat transfer performance of the heat pipe is proportional to the area of the evaporation portion in the in-plane direction of the back surface of the base plate. In the technology disclosed in Patent Document 1, in order to improve the cooling performance of the cooler by improving the heat transfer performance of the heat pipe, the area of the evaporation portion in the in-plane direction of the back surface of the base plate must be increased, which in turn increases the size of the base plate. This causes a problem of leading to an increase in size of the cooler.

[0006] The present disclosure has been made in view of the foregoing, and an object thereof is to obtain a cooler capable of improving the cooling performance of the cooler while suppressing an increase in size of the cooler.

[0007] To solve the above-mentioned problems and achieve the objective, the cooler according to this disclosure is a cooler comprising a base plate having a first surface to which a heat-generating element is attached and a second surface opposite to the first surface. When the direction parallel to the direction from the first surface to the second surface is defined as the first direction, the direction intersecting the first direction is defined as the second direction, and the direction intersecting both the first and second directions is defined as the third direction, the cooler according to this disclosure comprises a heat transfer block provided on the second surface of the base plate and extending in the first direction, and a heat pipe having an evaporation section inserted into the heat transfer block and extending from the heat transfer block toward the opposite side of the base plate. The cooler according to this disclosure also comprises fins attached to the heat pipe and a cooling fan that generates airflow in the second direction and guides the airflow toward the heat transfer block, heat pipe and fins.

[0008] The cooler described herein has the effect of improving the cooling performance of the cooler while suppressing an increase in the size of the cooler.

[0009] A perspective view showing the configuration of a drive device equipped with a cooler according to Embodiment 1. A cross-sectional view along line II-II shown in Figure 1. A cross-sectional view along line III-III shown in Figure 2. A cross-sectional view along line IV-IV shown in Figure 2. A perspective view showing the configuration of the heat transfer block and heat pipe in Embodiment 1. A plan view showing the configuration of the base plate, heat transfer block, heat pipe and fins in Embodiment 1. A cross-sectional view showing the configuration of a drive device equipped with a cooler according to Embodiment 2, corresponding to the cross-sectional view along line II-II shown in Figure 1. A cross-sectional view showing the configuration of a drive device equipped with a cooler according to Embodiment 2, corresponding to the cross-sectional view along line VIII-VIII shown in Figure 7. A cross-sectional view showing the configuration of a drive device equipped with a cooler according to Modification 1 of Embodiment 2, corresponding to the cross-sectional view along line VIII-VIII shown in Figure 7. A cross-sectional view showing the configuration of a drive device equipped with a cooler according to Modification 2 of Embodiment 2, corresponding to the cross-sectional view along line VIII-VIII shown in Figure 7.

[0010] The cooler according to the embodiment will be described in detail below with reference to the drawings. The cooler is a cooler for semiconductor devices. In this disclosure, as an example, a cooler for a drive device in the field of machine tools and FA (Factory Automation) will be described. However, the cooler is not limited to drive devices and may be a cooler for semiconductor devices other than drive devices. For example, the cooler may be a cooler for semiconductor devices in railway vehicles.

[0011] Embodiment 1. Figure 1 is a perspective view showing the configuration of a drive device 100 equipped with a cooler 2 according to Embodiment 1. Figure 2 is a cross-sectional view along the line II-II shown in Figure 1. Figure 3 is a cross-sectional view along the line III-III shown in Figure 2. Figure 4 is a cross-sectional view along the line IV-IV shown in Figure 2. Figure 5 is a perspective view showing the configuration of the heat transfer block 30 and heat pipe 40 in Embodiment 1. Figure 6 is a plan view showing the configuration of the base plate 20, heat transfer block 30, heat pipe 40 and fin 50 in Embodiment 1. The drive device 100 is, for example, a device installed in the control panel of a machine tool. As shown in Figures 1 to 3, the drive device 100 includes a control unit 1 and a cooler 2 that cools the control unit 1. The control unit 1 has a power device 10. The power device 10 controls the current supplied to a motor (not shown). When the power device 10 is driven, heat is generated from the power device 10.

[0012] The cooler 2 comprises a base plate 20, a plurality of heat transfer blocks 30, a plurality of heat pipes 40, a plurality of fins 50, and a cooling fan 60. When describing the direction of each component of the cooler 2 below, we will follow the right-handed XYZ coordinate system shown in Figure 1. The X, Y, and Z axes are three axes perpendicular to each other. Of each axis, the direction indicated by the arrow is considered positive, and the direction opposite to the arrow is considered negative. The direction along the X axis (X-axis direction) and the direction along the Y axis (Y-axis direction) are included in the horizontal direction. The direction along the Z axis (Z-axis direction) is considered the vertical direction. Furthermore, the positive direction of the Z axis is considered upward, and the negative direction of the Z axis is considered downward. These directions are set for convenience when describing each component of the cooler 2 and do not specify the orientation in which the cooler 2 is used. The direction parallel to the direction from the first surface 20a to the second surface 20b of the base plate 20, which will be described later, is defined as the first direction, the direction intersecting the first direction is defined as the second direction, and the direction intersecting both the first and second directions is defined as the third direction. The intersecting direction includes both orthogonal directions and inclined directions. In this embodiment, as an example, we will describe the case in which the Y-axis direction corresponds to the first direction, the Z-axis direction corresponds to the second direction, and the X-axis direction corresponds to the third direction. The white arrow A shown in Figure 2, etc., indicates the airflow generated by the cooling fan 60. Hereinafter, the direction in which the air flows will be referred to as the ventilation direction. The ventilation direction coincides with the Z-axis direction.

[0013] The base plate 20 is a rectangular plate-shaped member extending in the X-axis direction and the Z-axis direction. The base plate 20 has a first surface 20a and a second surface 20b. Both the first surface 20a and the second surface 20b are planes parallel to the X-axis direction and the Z-axis direction (XZ plane). The first surface 20a is the surface facing the control unit 1 and is the surface to which the power device 10, which is a heat-generating element, is attached. Note that the heat-generating element is not limited to the power device 10, but may be any electronic device that generates heat, such as a semiconductor element or a capacitor. In this embodiment, multiple power devices 10 are attached to the first surface 20a, but one power device 10 may be attached. The second surface 20b is the surface opposite to the first surface 20a. As shown in Figures 2 and 3, the second surface 20b has multiple mounting recesses 20c formed therein that are recessed toward the first surface 20a in the Y-axis direction. Multiple mounting recesses 20c are arranged with spacing between them in the X-axis and Z-axis directions. The Y-axis direction is parallel to the direction from the first surface 20a to the second surface 20b.

[0014] As shown in Figure 1, each of the multiple heat transfer blocks 30 is a block-shaped member that is provided on the second surface 20b of the base plate 20 and extends in the Y-axis direction. In this embodiment, the shape of each heat transfer block 30 is cubic, but it may be changed as appropriate. As shown in Figures 2 and 3, a part of each heat transfer block 30 is embedded in the mounting recess 20c of the base plate 20. The remaining part of each heat transfer block 30 is exposed from the mounting recess 20c of the base plate 20. The part of the heat transfer block 30 that is embedded in the mounting recess 20c of the base plate 20 has the function of receiving heat from the base plate 20. The part of the heat transfer block 30 that is exposed from the mounting recess 20c of the base plate 20 has the function of dissipating the heat received from the base plate 20 into the air.

[0015] As shown in Figure 4, the multiple heat transfer blocks 30 are spaced apart from each other in the X-axis and Z-axis directions, and are also staggered in the Z-axis direction. In other words, adjacent heat transfer blocks 30 in the Z-axis direction are offset in the X-axis direction. This configuration forms ventilation paths 70, which are airflow paths, between the heat transfer blocks 30. Although there are multiple ventilation paths 70 in the cooler 2, Figure 4 shows one ventilation path 70. The ventilation path 70 extends from the negative direction to the positive direction in the Z-axis direction, making multiple right-angle turns in the X-axis direction. The air passing through the ventilation path 70 flows from the negative direction to the positive direction in the Z-axis direction, making multiple right-angle turns in the X-axis direction. In this embodiment, some of the adjacent heat transfer blocks 30 in the Z-axis direction overlap when viewed along the Z-axis direction, but they do not have to overlap. The length L3 of the heat transfer block 30 in the X-axis direction is longer than the spacing G1 between adjacent heat transfer blocks 30 in the X-axis direction. The spacing G1 is the distance between adjacent heat transfer blocks 30 in the X-axis direction.

[0016] Each heat transfer block 30 has one block-side socket 30a. The cooler 2 as a whole has multiple block-side sockets 30a. The multiple block-side sockets 30a are spaced apart from each other in the X-axis and Z-axis directions. Adjacent block-side sockets 30a in the X-axis direction are arranged in a line along the X-axis. That is, adjacent block-side sockets 30a in the X-axis direction are in the same position in the Z-axis direction. Adjacent block-side sockets 30a in the Z-axis direction are arranged alternately in the Z-axis direction. That is, adjacent block-side sockets 30a in the Z-axis direction are offset from each other in the X-axis direction. The shape of the block-side sockets 30a when viewed along the Y-axis direction is not particularly limited as long as it corresponds to the shape of the heat pipe 40, but in this embodiment it is rectangular. As shown in Figures 2 and 3, the block-side insertion port 30a is a through-hole that penetrates the heat transfer block 30 in the Y-axis direction in this embodiment, but it may also be a recess that is open only on the side of the heat transfer block 30 facing the fins 50.

[0017] Each of the multiple heat pipes 40 is inserted into the heat transfer block 30 and extends from the heat transfer block 30 toward the opposite side from the base plate 20. In this embodiment, for example, the heat pipes 40 are flat plates that extend straight in one direction. In this embodiment, the extension direction of each heat pipe 40 is parallel to the Y-axis direction, but it may be inclined toward the Y-axis direction. A coolant flows inside each heat pipe 40. The coolant is, for example, pure water or antifreeze. As shown in Figure 4, the multiple heat pipes 40 are arranged with space between them in the X-axis direction and the Z-axis direction. Adjacent heat pipes 40 in the X-axis direction are arranged in a line along a straight line in the X-axis direction. That is, adjacent heat pipes 40 in the X-axis direction are positioned at the same location in the Z-axis direction. Adjacent heat pipes 40 in the Z-axis direction are arranged alternately in the Z-axis direction. That is, adjacent heat pipes 40 in the Z-axis direction are offset from each other in the X-axis direction.

[0018] As shown in Figures 2 and 3, each heat pipe 40 has an evaporation section 40a and a condensation section 40b. The evaporation section 40a is the part that is inserted into the heat transfer block 30. The evaporation section 40a includes the end of the heat pipe 40 that faces the base plate 20. The evaporation section 40a has the function of receiving heat from both the base plate 20 and the heat transfer block 30, or from the heat transfer block 30 alone, to evaporate the refrigerant. One evaporation section 40a of the heat pipe 40 is inserted into each of the multiple block-side insertion ports 30a. In other words, in this embodiment, one heat transfer block 30 has one evaporation section 40a of the heat pipe 40 inserted into it. The evaporation section 40a is inserted all the way to the back of the block-side insertion port 30a. The end of the evaporation section 40a that faces the base plate 20 is in contact with the second surface 20b of the base plate 20 (the bottom surface of the mounting recess 20c). With this configuration, the evaporation section 40a of this embodiment can receive heat from both the base plate 20 and the heat transfer block 30.

[0019] Furthermore, it is sufficient that at least one heat pipe 40's evaporation section 40a is inserted into one heat transfer block 30. Also, the evaporation section 40a is inserted partway into the block-side insertion opening 30a, and the end of the evaporation section 40a facing the base plate 20 does not need to be in contact with the second surface 20b of the base plate 20. In this configuration, the evaporation section 40a can receive heat only from the heat transfer block 30. Specifically, the heat generated from the power device 10 is transferred from the base plate 20 to the heat transfer block 30, and then from the heat transfer block 30 to the evaporation section 40a. In this embodiment, the evaporation section 40a is perpendicular to the second surface 20b which is parallel to the XZ plane, but it may also be oblique to the second surface 20b.

[0020] The condensing section 40b is the part exposed to the outside of the heat transfer block 30. The condensing section 40b has the function of cooling and condensing the refrigerant that has received heat in the evaporation section 40a. The condensing section 40b extends in the positive direction of the Y-axis toward the fins 50 from the end of the evaporation section 40a that faces the fins 50. The condensing section 40b includes the end of the heat pipe 40 that faces the fins 50.

[0021] As shown in Figure 4, the cross-sectional shape of the heat pipe 40 when cut in a direction perpendicular to the Y-axis direction, which is the extension direction of the heat pipe 40, is flattened. In other words, the heat pipe 40 has a shape in which the thickness is thin in one direction. For example, the cross-sectional shape of the heat pipe 40 may be a rectangle having a long side parallel to the Z-axis direction and a short side parallel to the X-axis direction, as in this embodiment, but it may also be an ellipse having a long axis parallel to the Z-axis direction and a short axis parallel to the X-axis direction. The evaporation section 40a of the heat pipe 40 is inserted into the heat transfer block 30 so that the longitudinal direction of the cross-section of the heat pipe 40 is the same as the Z-axis direction, which is the direction in which the cooling fan 60 guides the airflow (indicated by the white arrow A). Note that in Figure 4, only the cross-section of the condensation section 40b of the heat pipe 40 is shown, but for the sake of explanation, the reference numeral for the evaporation section 40a is also included.

[0022] As shown in Figure 2, the length L1 of the heat transfer block 30 in the Y-axis direction is longer than the length L2 of the base plate 20 in the Y-axis direction in this embodiment. As shown in Figure 3, the length L3 of the heat transfer block 30 in the X-axis direction is longer than the length L4 of the heat pipe 40 in the X-axis direction in this embodiment. The thermal conductivity of the heat transfer block 30 is higher than that of the base plate 20 and lower than that of the heat pipe 40 in this embodiment. Examples of materials for the heat transfer block 30 include copper, graphite, and aluminum. Examples of materials for the base plate 20 include aluminum, copper, and stainless steel.

[0023] As shown in Figure 4, the area of ​​the cross-section of the heat transfer block 30 when cut in a direction perpendicular to the Y-axis is larger than the area of ​​the cross-section of the heat pipe 40 when cut in a direction perpendicular to the Y-axis. In other words, the area of ​​the heat transfer block 30 in contact with the base plate 20 is larger than the area of ​​the heat pipe 40 in contact with the base plate 20. Although the heat transfer block 30 shown in Figure 4 is not a cross-section, the area of ​​the cross-section of the heat transfer block 30 when cut in a direction perpendicular to the Y-axis is the same as the area of ​​the heat transfer block 30 shown in Figure 4. Note that the area of ​​the cross-section of the heat transfer block 30 when cut in a direction perpendicular to the Y-axis may be the same as the area of ​​the cross-section of the heat pipe 40 when cut in a direction perpendicular to the Y-axis.

[0024] As shown in Figure 1, each of the multiple fins 50 is a rectangular plate-shaped member attached to the heat pipe 40, positioned on the opposite side of the base plate 20 with the heat transfer block 30 in between in the Y-axis direction. Each fin 50 has the function of dissipating heat generated from the power device 10 into the air. Each fin 50 extends in the X-axis direction and the Z-axis direction. Each fin 50 has multiple fin-side insertion openings 50a formed therein. The multiple fin-side insertion openings 50a are spaced apart from each other in the X-axis direction and the Z-axis direction. Adjacent fin-side insertion openings 50a in the X-axis direction are arranged in a line along a straight line in the X-axis direction. That is, adjacent fin-side insertion openings 50a in the X-axis direction are in the same position in the Z-axis direction. Adjacent fin-side insertion openings 50a in the Z-axis direction are arranged alternately in the Z-axis direction. That is, adjacent fin-side insertion openings 50a in the Z-axis direction are offset from each other in the X-axis direction. The shape of the fin-side insertion port 50a when viewed along the Y-axis is not particularly limited as long as it corresponds to the shape of the heat pipe 40, but in this embodiment it is rectangular. As shown in Figures 2 and 3, the fin-side insertion port 50a is a through-hole that penetrates the fin 50 in the Y-axis direction.

[0025] Each of the multiple block-side insertion ports 30a has one condensation portion 40b of a heat pipe 40 inserted into it. Multiple condensation portions 40b of heat pipes 40 are inserted into one fin 50. Multiple fins 50 into which multiple condensation portions 40b of heat pipes 40 are inserted are arranged in the Y-axis direction, which is the extension direction of the heat pipe 40. Each condensation portion 40b of a heat pipe 40 is inserted into multiple fins 50 that are spaced apart from each other in the Y-axis direction. As shown in Figure 6, in this embodiment, the distance G1 between adjacent heat transfer blocks 30 in the X-axis direction is wider than the distance G2 between adjacent fins 50 in the Y-axis direction.

[0026] As shown in Figure 2, the cooling fan 60 is a device that generates airflow in the Z-axis direction and directs cooling air to the heat transfer block 30, heat pipes 40, and fins 50. The cooling fan 60 is attached to the second surface 20b of the base plate 20 via a connector (not shown). The cooling fan 60 is positioned above the heat transfer block 30, heat pipes 40, and fins 50, and away from them. The cooling fan 60 is positioned downstream of the heat transfer block 30, heat pipes 40, and fins 50 in the ventilation direction. By driving the cooling fan 60, airflow is generated that flows from the negative direction (downward) to the positive direction (upward) in the Z-axis direction, and the generated airflow strikes the heat transfer block 30, heat pipes 40, and fins 50. The cooler 2 may further include a ventilation cover that surrounds the heat transfer block 30, heat pipes 40, and fins 50.

[0027] Now, referring to Figure 2, the flow of heat dissipation from the power device 10 will be explained. The power device 10, base plate 20, heat transfer block 30 and the evaporation section 40a of the heat pipe 40, the condensation section 40b of the heat pipe 40, and the fins 50 are arranged in that order from the negative to the positive direction in the Y-axis direction. The heat generated from the power device 10 is transferred to the heat transfer block 30 and the evaporation section 40a of the heat pipe 40 via the base plate 20. The heat transferred to the evaporation section 40a of the heat pipe 40 is then transferred to the condensation section 40b of the heat pipe 40 and the fins 50. The heat transferred to the heat transfer block 30, the condensation section 40b of the heat pipe 40, and the fins 50 is then dissipated into the air by the airflow generated by the cooling fan 60.

[0028] Next, the effects of the cooler 2 according to Embodiment 1 will be described.

[0029] In this embodiment, as shown in Figures 2 and 3, the cooler 2 comprises a base plate 20 having a first surface 20a to which a power device 10, which is a heat-generating element, is attached, and a second surface 20b that is opposite to the first surface 20a. The cooler 2 includes a heat transfer block 30 provided on the second surface 20b of the base plate 20 and extending in the Y-axis direction (first direction). The cooler 2 also includes a heat pipe 40 having an evaporation section 40a inserted into the heat transfer block 30 and extending from the heat transfer block 30 toward the opposite side of the base plate 20. The cooler 2 also includes fins 50 attached to the heat pipe 40. The cooler 2 also includes a cooling fan 60 that generates airflow in the Z-axis direction (second direction) and guides the airflow toward the heat transfer block 30, the heat pipe 40, and the fins 50. In this embodiment, the evaporation section 40a, which is part of the heat pipe 40, is inserted into the heat transfer block 30 that extends in the Y-axis direction (first direction), thereby securing a heat transfer area for the evaporation section 40a in the out-of-plane direction (Y-axis direction) of the base plate 20. In other words, the heat transfer area of ​​the evaporation section 40a can be increased without increasing the size of the base plate 20 in the in-plane direction (size of the XZ plane). Furthermore, by transferring the heat transferred to the base plate 20 to the heat pipe 40 via the heat transfer block 30, the heat transfer performance of the heat pipe 40 can be improved. In addition, by dissipating the heat transferred to the heat transfer block 30 into the air from the heat transfer block 30 itself, the heat transfer from the base plate 20 to the heat transfer block 30 can be improved, thus mitigating the localized temperature rise of the base plate 20. Therefore, the cooling performance of the cooler 2 can be improved. On the other hand, since it is not necessary to increase the area of ​​the evaporation section 40a in the in-plane direction of the base plate 20 in order to improve the cooling performance of the cooler 2, it is not necessary to increase the size of the base plate 20. Therefore, it is possible to suppress the enlargement of the cooler 2. As described above, in this embodiment, it is possible to improve the cooling performance of the cooler 2 while suppressing the enlargement of the cooler 2. This makes it possible to realize a compact and high-output drive unit 100.

[0030] In this embodiment, the cooling performance of the cooler 2 can be improved while suppressing an increase in the size of the cooler 2, and furthermore, the following effects can also be achieved.

[0031] In this embodiment, as shown in Figure 2, the length L1 of the heat transfer block 30 in the Y-axis direction (first direction) is longer than the length L2 of the base plate 20 in the Y-axis direction (first direction). This configuration ensures sufficient length of the evaporation section 40a inserted into the heat transfer block 30. Therefore, compared to a configuration in which the heat pipe 40 is directly attached to the base plate 20, the heat transfer area of ​​the evaporation section 40a can be secured in the out-of-plane direction (Y-axis direction) of the base plate 20. Consequently, the heat transfer area of ​​the evaporation section 40a can be increased without increasing the in-plane size of the base plate 20, thereby improving the heat transfer performance of the heat pipe 40.

[0032] In this embodiment, the thermal conductivity of the heat transfer block 30 shown in Figure 2 is higher than that of the base plate 20, and lower than that of the heat pipe 40. With this configuration, the evaporation section 40a is inserted into the heat transfer block 30, which has a higher thermal conductivity than the base plate 20. Therefore, compared to a configuration in which the heat pipe 40 is directly inserted into the base plate 20 by increasing the length of the base plate 20 in the Y-axis direction (first direction), the heat transfer from the base plate 20 to the evaporation section 40a can be improved.

[0033] As shown in Figure 2, the YZ plane formed by the longitudinal direction (Z-axis direction) of the cross-section of the heat pipe 40 and the extension direction (Y-axis direction) of the heat pipe 40 is the largest surface in contact with the heat transfer block 30 and the evaporation section 40a. In order to facilitate heat transfer in the desired direction and to the desired surface, the length of the heat transfer block 30 in the direction perpendicular to the surface to which heat is to be transferred should be increased. In this embodiment, the direction in which heat is to be transferred is the extension direction of the heat pipe 40, and the surface to which heat is to be transferred is the largest YZ plane in contact with the heat transfer block 30 and the evaporation section 40a. In order to improve heat transfer in this YZ plane, the length of the heat transfer block 30 in the direction perpendicular to the YZ plane should be increased. In this respect, in this embodiment, as shown in Figure 3, the length L3 of the heat transfer block 30 in the X-axis direction (third direction) is longer than the length L4 of the heat pipe 40 in the X-axis direction (third direction). This configuration improves heat transfer in the YZ plane, which is the largest surface area where the heat transfer block 30 and the evaporation section 40a are in contact. In other words, it improves heat transfer from the heat transfer block 30 to the evaporation section 40a.

[0034] In this embodiment, as shown in Figure 2, the heat pipe 40 has a condensation portion 40b that is inserted into the fin 50, and there are multiple heat pipes 40. Furthermore, multiple condensation portions 40b of heat pipes 40 are inserted into a single fin 50. With this configuration, heat can be diffused in the in-plane direction of the fin 50 (within the XZ plane of the fin 50) compared to the case where one condensation portion 40b of one heat pipe 40 is inserted into a single fin 50.

[0035] If the spacing G1 between heat transfer blocks 30 shown in Figure 6 is narrower than the spacing G2 between fins 50, the air induced by the cooling fan 60 will have difficulty flowing towards the heat transfer blocks 30, and the heat transfer blocks 30 may not be able to fully perform their function as a heat dissipation unit. In this embodiment, as shown in Figure 6, there are multiple heat transfer blocks 30 and multiple fins 50, and the multiple heat transfer blocks 30 are spaced apart from each other in the X-axis direction (third direction). The multiple fins 50 are spaced apart from each other in the Y-axis direction (first direction), and the spacing G1 between adjacent heat transfer blocks 30 in the X-axis direction (third direction) is wider than the spacing G2 between adjacent fins 50 in the Y-axis direction (first direction). With these configurations, the pressure loss of air in the fins 50, heat pipes 40 and heat transfer blocks 30 is balanced. As a result, air flows more evenly through the fins 50, heat pipes 40, and heat transfer blocks 30, and a high average heat dissipation effect is obtained for the cooler 2 as a whole.

[0036] In this embodiment, as shown in Figure 4, at least one evaporation section 40a of a heat pipe 40 is inserted into one heat transfer block 30. Specifically, in this embodiment, one evaporation section 40a of one heat pipe 40 is inserted into one heat transfer block 30. This configuration increases the surface area in contact between the surface of the heat transfer block 30 and the wind (air), thereby expanding the heat dissipation area of ​​the heat transfer block 30.

[0037] In this embodiment, as shown in Figure 4, there are multiple heat transfer blocks 30, and the heat pipe 40 has a flattened shape. The evaporation portion 40a of the heat pipe 40 is inserted into the heat transfer block 30 such that the longitudinal direction of the cross-section of the heat pipe 40 when cut in a direction perpendicular to the Y-axis direction (first direction) and the Z-axis direction (second direction), which is the direction in which the cooling fan 60 guides the airflow, are in the same orientation. With these configurations, the area that the heat pipe 40 obstructs the airflow can be minimized, thereby reducing the pressure loss of the airflow in the cooler 2 and increasing the airflow rate passing over the surface of the heat pipe 40.

[0038] In this embodiment, as shown in Figure 4, the multiple heat transfer blocks 30 are arranged alternately with spacing between them in at least one of the Z-axis direction (second direction) and the X-axis direction (third direction). Specifically, the multiple heat transfer blocks 30 are arranged alternately in the Z-axis direction with spacing between them in both the Z-axis direction and the X-axis direction. This configuration forms ventilation paths 70, which are air passages, between the heat transfer blocks 30, thereby reducing the pressure loss of the air in the cooler 2 and increasing the airflow rate passing over the surface of the heat transfer blocks 30. Furthermore, this configuration allows air to strike the heat transfer blocks 30 and disrupt the airflow, promoting heat exchange between the heat transfer blocks 30 and the air, and improving the heat dissipation from the heat transfer blocks 30 into the air. In particular, in this embodiment, parts of adjacent heat transfer blocks 30 in the Z-axis direction (ventilation direction) overlap each other when viewed along the Z-axis direction, making it easier for air to strike the heat transfer blocks 30 and further disrupting the airflow.

[0039] In this embodiment, as shown in Figure 4, the cross-sectional area of ​​the heat transfer block 30 when cut in a direction perpendicular to the Y-axis is larger than the cross-sectional area of ​​the heat pipe 40 when cut in a direction perpendicular to the Y-axis. In other words, the area in contact between the heat transfer block 30 and the base plate 20 is larger than the area in contact between the heat pipe 40 and the base plate 20. This configuration allows for an increased area of ​​heat reception from the base plate 20.

[0040] Embodiment 2. Next, the cooler 2A according to Embodiment 2 will be described with reference to Figures 7 and 8. This embodiment differs from Embodiment 1 described above in that multiple heat pipes 40 with evaporation sections 40a are inserted into a single heat transfer block 31. In Embodiment 2, parts that overlap with Embodiment 1 described above are denoted by the same reference numerals and their description is omitted.

[0041] FIG. 7 is a cross-sectional view illustrating a configuration of a drive device 100A including a cooler 2A according to a second embodiment, and is a view corresponding to a cross-sectional view taken along line II-II shown in FIG. 1. FIG. 8 is a cross-sectional view illustrating a configuration of a drive device 100A including a cooler 2A according to the second embodiment, and is a cross-sectional view taken along line VIII-VIII shown in FIG. 7. As shown in FIGS. 7 and 8, the number of each of the base plate 20 and the heat transfer block 31 is one in the present embodiment. One base plate 20 is provided with one heat transfer block 31. One mounting recess 20c is formed in the base plate 20.

[0042] As shown in FIG. 8, the heat transfer block 31 is formed with a plurality of block-side insertion ports 31a. The plurality of block-side insertion ports 31a are arranged spaced apart from each other in the X-axis direction and the Z-axis direction. The block-side insertion ports 31a adjacent in the X-axis direction are arranged in a line on a straight line along the X-axis direction. That is, the block-side insertion ports 31a adjacent in the X-axis direction have the same position in the Z-axis direction. The block-side insertion ports 31a adjacent in the Z-axis direction are arranged alternately in the Z-axis direction. That is, the block-side insertion ports 31a adjacent in the Z-axis direction are arranged shifted from each other in the X-axis direction.

[0043] One heat pipe 40 is inserted into each of the plurality of block-side insertion ports 31a. Evaporating portions 40a of the plurality of heat pipes 40 are inserted into one heat transfer block 31. The plurality of heat pipes 40 are arranged spaced apart from each other in the X-axis direction and the Z-axis direction. The heat pipes 40 adjacent in the X-axis direction are arranged in a line on a straight line along the X-axis direction. That is, the heat pipes 40 adjacent in the X-axis direction have the same position in the Z-axis direction. The heat pipes 40 adjacent in the Z-axis direction are arranged alternately in the Z-axis direction. That is, the heat pipes 40 adjacent in the Z-axis direction are arranged shifted from each other in the X-axis direction.

[0044] Next, effects of the cooler 2A according to the second embodiment will be described.

[0045] In this embodiment, as shown in Figures 7 and 8, multiple heat pipes 40 have evaporation sections 40a inserted into a single heat transfer block 31. This configuration allows heat to be transferred in the direction in which the multiple heat pipes 40 are aligned within the heat transfer block 31. Therefore, the heat transfer performance to the heat pipes 40 located away from the heat source within the power device 10 can be improved via the heat transfer block 31. This improves the operability of the heat pipes 40 even when there is a localized temperature rise in the base plate 20.

[0046] Next, a modified example of Embodiment 2 will be described.

[0047] In this embodiment, there is one heat transfer block 31 into which the evaporation sections 40a of multiple heat pipes 40 are inserted, but there may be multiple. For example, as shown in Figure 9, there may be three heat transfer blocks 32, or as shown in Figure 10, there may be four heat transfer blocks 33. Figure 9 is a cross-sectional view showing the configuration of a drive device 100B equipped with a cooler 2B according to modification 1 of Embodiment 2, and corresponds to the cross-sectional view taken along line VIII-VIII shown in Figure 7. Figure 10 is a cross-sectional view showing the configuration of a drive device 100C equipped with a cooler 2C according to modification 2 of Embodiment 2, and corresponds to the cross-sectional view taken along line VIII-VIII shown in Figure 7.

[0048] In Modification 1 shown in FIG. 9, the number of base plates 20 is one, and the number of heat transfer blocks 32 is three. Three heat transfer blocks 32 are provided on one base plate 20. Although not shown in the figures, three mounting recesses 20c are formed in the base plate 20. The three heat transfer blocks 32 are staggered from each other at intervals in the X-axis direction. That is, the heat transfer blocks 32 adjacent to each other in the X-axis direction are arranged offset from each other in the Z-axis direction. In this modification, portions of the heat transfer blocks 32 adjacent to each other in the X-axis direction overlap each other when viewed along the X-axis direction, but they do not need to overlap each other. The ventilation path 71 extends linearly from the negative direction to the positive direction in the Z-axis direction. The air passing through the ventilation path 71 flows linearly from the negative direction to the positive direction in the Z-axis direction. Each heat transfer block 32 has a shape extending in the Z-axis direction, which is the direction in which the heat pipes 40 inserted into each heat transfer block 32 are arranged. Specifically, in the present embodiment, the shape of each heat transfer block 32 when viewed along the Y-axis direction is a rectangle that is longer in the Z-axis direction than in the X-axis direction.

[0049] A plurality of block-side insertion ports 32a are formed in each heat transfer block 32. The plurality of block-side insertion ports 32a formed in the same heat transfer block 32 are arranged at intervals from each other in the Z-axis direction. The plurality of block-side insertion ports 32a formed in the same heat transfer block 32 are arranged in a single row on a straight line along the Z-axis direction. That is, the plurality of block-side insertion ports 32a formed in the same heat transfer block 32 have the same position in the X-axis direction. The block-side insertion ports 32a of the heat transfer blocks 32 adjacent to each other in the X-axis direction are staggered from each other at intervals in the X-axis direction. That is, the block-side insertion ports 32a of the heat transfer blocks 32 adjacent to each other in the X-axis direction are arranged offset from each other in the Z-axis direction.

[0050] Each of the multiple block-side insertion ports 32a has one heat pipe 40 inserted into it. Multiple heat pipes 40 have evaporation sections 40a inserted into one heat transfer block 32. Multiple heat pipes 40 inserted into the same heat transfer block 32 are spaced apart from each other in the Z-axis direction. Multiple heat pipes 40 inserted into the same heat transfer block 32 are arranged in a line along a straight line in the Z-axis direction. In other words, multiple heat pipes 40 inserted into the same heat transfer block 32 are positioned at the same location in the X-axis direction. Heat pipes 40 inserted into adjacent heat transfer blocks 32 in the X-axis direction are spaced apart from each other in an alternating pattern in the X-axis direction. In other words, heat pipes 40 inserted into adjacent heat transfer blocks 32 in the X-axis direction are offset from each other in the Z-axis direction. Even in this modified form, the same effects as in the above-described embodiment 2 can be achieved.

[0051] In the modified example 2 shown in Figure 10, there is one base plate 20 and four heat transfer blocks 33. Four heat transfer blocks 33 are provided on one base plate 20. Although not shown in the figure, four mounting recesses 20c are formed on the base plate 20. The four heat transfer blocks 33 are arranged alternately with space between them in the Z-axis direction. That is, adjacent heat transfer blocks 33 in the Z-axis direction are offset from each other in the X-axis direction. In this modified example, some parts of adjacent heat transfer blocks 33 in the Z-axis direction overlap when viewed along the Z-axis direction, but they do not have to overlap. The ventilation path 72 extends from the negative direction to the positive direction in the Z-axis direction, making multiple right-angle turns in the X-axis direction. The air passing through the ventilation path 72 flows from the negative direction to the positive direction in the Z-axis direction, making multiple right-angle turns in the X-axis direction. Each heat transfer block 33 has a shape that extends in the X-axis direction, which is the direction in which the heat pipes 40 inserted into each heat transfer block 33 are aligned. When viewed along the Y-axis, the shape of each heat transfer block 33 in this embodiment is a rectangle that is longer in the X-axis direction than in the Z-axis direction.

[0052] Each heat transfer block 33 has multiple block-side insertion ports 33a formed therein. Multiple block-side insertion ports 33a formed on the same heat transfer block 33 are spaced apart from each other in the X-axis direction. Multiple block-side insertion ports 33a formed on the same heat transfer block 33 are arranged in a straight line along the X-axis direction. In other words, the positions of multiple block-side insertion ports 33a formed on the same heat transfer block 33 coincide in the Z-axis direction. Block-side insertion ports 33a of adjacent heat transfer blocks 33 in the Z-axis direction are spaced apart from each other and arranged in an alternating pattern in the Z-axis direction. In other words, block-side insertion ports 33a of adjacent heat transfer blocks 33 in the Z-axis direction are offset from each other in the X-axis direction.

[0053] Each of the multiple block-side insertion ports 33a has one heat pipe 40 inserted into it. Multiple heat pipes 40 have evaporation sections 40a inserted into one heat transfer block 33. Multiple heat pipes 40 inserted into the same heat transfer block 33 are spaced apart from each other in the X-axis direction. Multiple heat pipes 40 inserted into the same heat transfer block 33 are arranged in a line along a straight line in the X-axis direction. In other words, multiple heat pipes 40 inserted into the same heat transfer block 33 are positioned at the same location in the Z-axis direction. Heat pipes 40 inserted into adjacent heat transfer blocks 33 in the Z-axis direction are spaced apart from each other and arranged alternately in the Z-axis direction. In other words, heat pipes 40 inserted into adjacent heat transfer blocks 33 in the Z-axis direction are offset from each other in the X-axis direction. Even in this modified form, the same effects as in the above-described embodiment 2 can be achieved.

[0054] The configuration in which multiple heat pipes 40 are inserted into each of the multiple heat transfer blocks 32 and 33 is not limited to the examples shown in Figures 9 and 10, and may be modified as appropriate.

[0055] The configurations shown in the above embodiments are merely examples, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention.

[0056] 1 Control unit, 2, 2A, 2B, 2C Cooler, 10 Power device, 20 Base plate, 20a First surface, 20b Second surface, 20c Mounting recess, 30, 31, 32, 33 Heat transfer block, 30a, 31a, 32a, 33a Block side insertion port, 40 Heat pipe, 40a Evaporation section, 40b Condensation section, 50 Fin, 50a Fin side insertion port, 60 Cooling fan, 70, 71, 72 Ventilation path, 100, 100A, 100B, 100C Drive unit.

Claims

1. A cooler comprising a base plate having a first surface to which a heating element is attached and a second surface opposite to the first surface, wherein, when the direction parallel to the direction from the first surface to the second surface is defined as the first direction, the direction intersecting the first direction is defined as the second direction, and the direction intersecting the first and second directions is defined as the third direction, the cooler comprises: a heat transfer block provided on the second surface of the base plate and extending in the first direction; a heat pipe having an evaporation section inserted into the heat transfer block and extending from the heat transfer block toward the side opposite to the base plate; fins attached to the heat pipe; and a cooling fan that generates airflow in the second direction and guides the airflow toward the heat transfer block, the heat pipe, and the fins.

2. The cooler according to claim 1, characterized in that the length of the heat transfer block in the first direction is longer than the length of the base plate in the first direction.

3. The cooler according to claim 1 or 2, characterized in that the thermal conductivity of the heat transfer block is higher than the thermal conductivity of the base plate and lower than the thermal conductivity of the heat pipe.

4. The cooler according to any one of claims 1 to 3, characterized in that the length of the heat transfer block in the third direction is longer than the length of the heat pipe in the third direction.

5. The cooler according to any one of claims 1 to 4, characterized in that the heat pipe has a condensing portion that is inserted into the fin, the number of heat pipes is multiple, and the condensing portions of multiple heat pipes are inserted into one fin.

6. The cooler according to any one of claims 1 to 5, wherein the number of heat transfer blocks and fins is multiple, the multiple heat transfer blocks are spaced apart from each other in the third direction, the multiple fins are spaced apart from each other in the first direction, and the spacing between adjacent heat transfer blocks in the third direction is wider than the spacing between adjacent fins in the first direction.

7. The cooler according to any one of claims 1 to 6, characterized in that at least one heat pipe's evaporation section is inserted into one of the heat transfer blocks.

8. The cooler according to any one of claims 1 to 7, characterized in that the number of heat transfer blocks is multiple, the shape of the heat pipe is flattened, the evaporation portion of the heat pipe is inserted into the heat transfer block such that the longitudinal direction of the cross-section of the heat pipe when cut in a direction perpendicular to the first direction and the second direction, which is the direction in which the cooling fan guides the airflow, are in the same orientation, and the multiple heat transfer blocks are arranged alternately with spacing between them in at least one of the second direction and the third direction.

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