Heat sinks, electronic equipment, and power converters

Abstract

To provide a heat sink, an electronic device, and a power converter, capable of efficiently cooling electronic components inside an enclosure and preventing damage to the electronic components even when water enters the enclosure.SOLUTION: An electronic device includes: an enclosure; a heat sink mounted on the enclosure such that a heat dissipating part is located outside the enclosure and a component surface is located inside the enclosure; and an electronic component mounted on the component surface. A connection part between the heat sink and the enclosure is waterproofed. The heat sink has a first edge of the component surface located above a vertical line and is arranged vertically such that a second side of the component surface opposite to a first side is located below the vertical line. On the component surface, a restraining part is formed above a component arrangement area to which the electronic component is mounted to restrain water from entering the component arrangement area.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a heat sink, an electronic device, and a power converter.

Background Art

[0002] A power conditioner that converts generated power such as in a photovoltaic power generation system and supplies it to a load or the like can be installed outdoors. Since an outdoor-installed power conditioner requires waterproof performance, a sealed or substantially sealed structure is adopted for the housing. In addition, in a power conversion device such as a power conditioner, a heat sink is adopted to cool semiconductor elements that generate heat when a large amount of power flows through them.

[0003] Patent Document 1 below discloses providing a water-absorbing material (a moisture-absorbing material is also possible) inside the housing as a dew condensation countermeasure in a sealed housing that houses a heat-generating device. Patent Document 2 below discloses a wall-mounted power conditioner installed outdoors. This power conditioner houses a heat sink vertically inside. A semiconductor is installed on the heat sink, and the heat generated by the semiconductor is dissipated by the heat sink. Patent Document 3 below discloses an installation-type power conversion device for charging an in-vehicle battery that does not cause an electric circuit component to fail even when water intrudes to a certain extent. This power conversion device houses a heat sink vertically inside the housing. The heat sink is provided on the heat dissipation surface on the back side of the component mounting surface of the substrate. A fan is provided above the back of the housing, and the heat sink is air-cooled by the flow of air inhaled from the air intake provided below. Patent Document 4 below discloses a heat sink that can reduce costs while suppressing a decrease in waterproof performance at the joint of a plurality of heat dissipation bodies, and a power conditioner using the same. The heat sink is integrally formed by fitting the ant-groove-shaped convex portion of the first heat dissipation body and the ant-groove-shaped concave portion of the second heat dissipation body. The heat sink is attached to a heat-generating element and housed inside the housing of the power conditioner, and is cooled by outside air inhaled into the housing by a fan provided below the heat sink.

Prior Art Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-198676 [Patent Document 2] Japanese Patent Publication No. 2013-110911 [Patent Document 3] Japanese Patent Publication No. 2020-36456 [Patent Document 4] International Publication No. 2014 / 013573 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the sealed enclosure disclosed in Patent Document 1 and the substantially sealed enclosure disclosed in Patent Document 2, there is a problem that heat accumulates inside the enclosure when a heat sink is placed inside, making cooling difficult. As in Patent Documents 3 and 4, it is necessary to provide a fan to draw in outside air into the enclosure and cool the heat sink, but there is a problem that it is difficult to prevent rainwater and other elements from entering.

[0006] The cooling performance of the heatsink can be ensured by attaching a heatsink to the enclosure, mounting semiconductor elements inside the enclosure, and positioning heat dissipation parts such as fins on the outside of the enclosure. Waterproofing between the heatsink and the enclosure is ensured by using sealant. However, maintaining the quality of sealant during manufacturing is difficult, and due to deterioration over time, the sealant may peel off during use, allowing rainwater to enter the enclosure. In addition, ensuring the quality of sealant requires significant costs for inspection equipment and labor, resulting in high costs. Furthermore, if double sealing is required, the necessary space is needed, leading to a larger enclosure and increased costs.

[0007] Therefore, the present disclosure aims to provide a heat sink, electronic device, and power converter that can efficiently cool electronic components inside the enclosure and prevent damage to the electronic components even if water enters the enclosure. [Means for solving the problem]

[0008] An electronic device relating to a certain aspect of the present disclosure includes a housing, a heat sink mounted to the housing such that the heat dissipation portion is located outside the housing and the component surface is located inside the housing, and an electronic component mounted on the component surface, wherein the connection between the heat sink and the housing is waterproofed, the heat sink is arranged vertically such that the first edge of the component surface is located above the vertical line and the second edge of the component surface opposite the first edge is located below the vertical line, and on the component surface, a suppression portion is formed above the component placement area on which the electronic component is mounted to suppress the intrusion of water into the component placement area. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a heat sink, electronic device, and power converter that can efficiently cool electronic components inside the enclosure and prevent damage to electronic components even if water enters the enclosure. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a perspective view showing the front appearance of a power converter according to an embodiment of this disclosure. [Figure 2] Figure 2 is a three-view drawing of the power converter shown in Figure 1. [Figure 3] Figure 3 is a vertical cross-sectional view showing the III-III cross-section of the power converter shown in Figure 2. [Figure 4] Figure 4 is a vertical cross-sectional view showing the IV-IV section of the power converter shown in Figure 2. [Figure 5] Figure 5 is a vertical cross-sectional view showing an enlarged view of the area within the ellipse shown in Figure 3. [Figure 6] Figure 6 is a vertical cross-sectional view showing the VI-VI section of the power converter shown in Figure 2. [Figure 7] Figure 7 is a vertical cross-sectional view showing grooves formed in the heat sink. [Figure 8] Figure 8 is a vertical cross-sectional view showing the flow of water when water enters the inside of the enclosure. [Figure 9] FIG. 9 is a front view showing a heat sink according to the first modification. [Figure 10] FIG. 10 is a diagram showing a groove that is not line-symmetric. [Figure 11] FIG. 11 is a diagram showing an arcuate groove. [Figure 12] FIG. 12 is a front view showing a heat sink according to the second modification. [Figure 13] FIG. 13 is a front view showing a heat sink according to the third modification. [Figure 14] FIG. 14 is a vertical cross-sectional view showing a groove having an inclined surface. [Figure 15] FIG. 15 is a vertical cross-sectional view showing a convex portion disposed on the heat sink. [Figure 16] FIG. 16 is a vertical cross-sectional view showing a step formed on the heat sink. [Figure 17] FIG. 17 is a vertical cross-sectional view showing a step different from that in FIG. 16 formed on the heat sink.

Mode for Carrying Out the Invention

[0011] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described. At least a part of the embodiments described below may be arbitrarily combined.

[0012] (1) The electronic device relating to the first aspect of the present disclosure includes a housing, a heat sink mounted on the housing such that the heat dissipation portion is located outside the housing and the component surface is located inside the housing, and an electronic component mounted on the component surface, wherein the connection between the heat sink and the housing is waterproofed, the heat sink is arranged vertically such that the first edge of the component surface is located above the vertical line and the second edge of the component surface opposite the first edge is located below the vertical line, and on the component surface, a suppression portion is formed above the component placement area on which the electronic component is mounted to suppress the intrusion of water into the component placement area. This allows for efficient cooling of the electronic component inside the housing and prevents damage to the electronic component (e.g., short circuits and fire accidents) even if water enters the housing.

[0013] (2) In (1) above, the suppression part may have a step in the vertical direction. This allows water that has entered the housing to move along the step and flow to areas where no electronic components are placed, thereby preventing damage to the electronic components by water.

[0014] (3) In (2) above, the step may constitute a groove formed on the component surface. This allows a relatively large amount of water to enter the housing, and the water to move within the groove and flow to areas where no electronic components are placed, thereby preventing damage to the electronic components from water.

[0015] (4) In (3) above, the upper part of the peripheral edge defining the groove may have a surface that forms an obtuse angle with respect to the component surface. This allows water that has entered the housing to easily enter the groove and flow to areas where no electronic components are placed, thereby preventing damage to the electronic components by water.

[0016] (5) In any one of (1) to (4) above, the suppression portion may include a vertical portion that extends vertically outside the component placement area. This ensures that water that enters the housing flows through areas where no electronic components are placed, and prevents damage to the electronic components from water.

[0017] (6) In (5) above, multiple restraining portions may be formed on the component surface, and the vertical portions may be shared by adjacent restraining portions. This reduces the amount of work required to form restraining portions on the component surface of the heat sink.

[0018] (7) In (1) above, the suppression portion may include a protrusion that extends from the component surface. This allows water that has entered the housing to move along the protrusion and flow to areas where no electronic components are located, thereby preventing damage to the electronic components by water.

[0019] (8) In (7) above, the protrusion may include a water-repellent member disposed within the groove so as to protrude from the groove formed on the component surface. This makes it easy to form a protrusion on the component surface of the heat sink.

[0020] (9) In any one of (1) to (5), (7) and (8) above, the suppression portion may have a shape in which the vertical height of the suppression portion is monotonically increasing or decreasing from the first end to the second end, or a shape in which the height is monotonically increasing from the first end to a specific point located between the first and second ends, and then monotonically decreasing from the specific point to the second end. This allows water that has entered the housing to move along the suppression portion and flow to areas where no electronic components are located, thereby preventing damage to the electronic components by water.

[0021] (10) A power converter relating to the second aspect of the present disclosure includes a group of electronic components that perform power conversion, a circuit board, and one of the electronic devices described in (1) to (9) above, wherein the group of electronic components and the circuit board are located inside the housing of the electronic device, and the group of electronic components includes electronic components mounted on the component surface of a heat sink, and the electronic components mounted on the component surface of the heat sink may be mounted on the circuit board. This allows for efficient cooling of the electronic components inside the housing and prevents damage to the electronic components even if water enters the housing.

[0022] (11) A heat sink according to a third aspect of the present disclosure includes a heat dissipation section and a component surface on which electronic components are mounted, wherein the component surface has a suppression section formed outside the component placement area on which electronic components are mounted, to suppress the intrusion of water into the component placement area. As a result, when the heat sink is arranged vertically such that the heat dissipation section is located outside the housing of the electronic device, the component surface is located inside the housing, and the portion of the component surface on which the suppression section is formed is located above the vertical line, the electronic components inside the housing can be efficiently cooled, and damage to the electronic components can be prevented even if water enters the housing.

[0023] [Details of the embodiments of this disclosure] In the following embodiments, identical parts are assigned the same reference numeral. Their names and functions are also identical. Therefore, detailed descriptions of them will not be repeated.

[0024] (Overall structure) Referring to Figure 1, the power converter 100 according to the embodiment of this disclosure includes a housing 102 and a heat sink 104. The power converter 100 constitutes a solar power generation system together with, for example, a PV (photovoltaic) panel. The power converter 100 converts DC power generated by a PV panel installed on the roof of a house, for example, into AC power and supplies it to electrical equipment such as home appliances in the house. The power converter 100 is fixedly installed, for example, on the exterior wall (not shown) of a house by mounting members (not shown) such that the heat sink 104 faces the exterior wall.

[0025] The orthogonal axes are shown in the lower left of Figure 1 (the same applies to Figures 2 and beyond). The X-axis is the axis in which the direction from the back to the front of the power converter 100 is positive. Similarly, the Y-axis and Z-axis are the axes in which the direction from the left side to the right side and from the bottom to the top of the power converter 100 are positive, respectively. "Left" and "right" refer to the power converter 100 as viewed from the front. When the power converter 100 is installed on the wall of a house, it is usually installed so that the Z-axis is aligned with the vertical line and the positive direction of the Z-axis is upward (i.e., in the opposite direction of gravity).

[0026] Referring to Figure 2, the housing 102 includes a front panel 110, a rear panel 112, a top panel 114, a bottom panel 116, a left side panel 118, and a right side panel 120, and is formed in a substantially rectangular parallelepiped shape. The front panel 110, rear panel 112, top panel 114, bottom panel 116, left side panel 118, and right side panel 120 are fixed to each other by screws or the like. The gaps at the joints between them are waterproofed (for example, sealed with caulking material). The rear panel 112, top panel 114, bottom panel 116, left side panel 118, and right side panel 120 may also be joined by welding or the like. If the front panel 110 is detachably attached to the rear panel 112, top panel 114, bottom panel 116, left side panel 118, and right side panel 120 by screws or the like, maintenance of the power converter 100 will be easier. The heat sink 104 includes a rectangular base portion 130 and a plurality of thin plates arranged in parallel to each other as heat dissipation fins 132. The base portion 130 is fixed to the rear panel 112 of the housing 102. The power converter 100 includes a power conversion board 140 for converting power and a control board 142 for control.

[0027] Referring to Figure 3, the base portion 130 of the heatsink 104 is fixed to the rear panel 112 of the housing 102 by a number of screws 160. The heat dissipation fins 132 of the heatsink 104 are located outside the housing 102. Specifically, as will be described later, an opening is formed in the center of the rear panel 112, and the component surface 134 of the base portion 130 that is on the rear panel 112 side is open to the inside of the housing 102. That is, while the heat dissipation fins 132 are located outside the housing 102, the component surface 134 of the base portion 130 is located inside the housing 102. Specifically, as will be described later, grooves 136 are formed on the component surface 134.

[0028] In Figure 3, the power conversion board 140 is fixed to the component side 134 (i.e., the base portion 130) of the heat sink 104 by screws 162 via a plurality of spacers 150. The power conversion board 140 may also be fixed to the rear panel 112 of the housing 102. The power conversion board 140 has circuits for realizing power conversion (for example, a DC / AC converter and a DC / DC converter) formed on it. The circuits for realizing power conversion are, for example, bridge circuits using semiconductor switching elements. The power conversion board 140 is mounted with a plurality of heat-generating components 154, such as semiconductor switching elements that constitute the circuits. The heat-generating components 154 are, for example, FETs (Field Effect Transistors). The heat-generating components 154 are connected to the power conversion board 140 by lead wires, and the main body of the heat-generating components 154 is attached to the component side 134 (i.e., the base portion 130) of the heat sink 104 by screws. When power is converted, the heat-generating components 154 are energized and become hot. The heat generated by the heat-generating component 154 is transferred to the base section 130, and further transferred to the heat dissipation fins 132, from which the heat is dissipated. As a result, the heat-generating component 154 is cooled and maintained at a temperature that will not cause damage during power conversion.

[0029] The control board 142 is fixed to the board fixing member 144 by screws 164 via a plurality of spacers 152. The board fixing member 144 is attached to one of the rear panel 112, top panel 114, bottom panel 116, left side panel 118, and right side panel 120 by fixing members (not shown). The electronic components mounted on the control board 142 are, for example, not directly related to the power conversion function and do not become as hot as the heat-generating components 154 even when energized.

[0030] Referring to Figure 4, as described above, the rear panel 112 has an opening 172 defined by the edge 170. Figure 4 is a cross-sectional view of the power converter 100 broken between the control board 142 and (more specifically, between the board fixing member 144 and (see Figure 3)) the power conversion board 140, as shown in Figure 2. Figure 4 can also be described as a front view of the power converter 100 with the front panel 110, control board 142 and board fixing member 144 removed. The component side 134 (i.e., base portion 130) of the heat sink 104 is attached to the rear panel 112 by a plurality of screws 160, as described above. Each of the multiple (i.e., three) power conversion boards 140 is attached to the component side 134 (i.e., base portion 130) of the heat sink 104 by a plurality (i.e., four) screws 162. In Figure 4, the shaded area shows the sealant 174 provided at the joint between the rear panel 112 and the component surface 134 for waterproofing purposes. Specifically, referring to Figure 5, the sealant 174 is positioned between the rear panel 112 and the component surface 134. The sealant is a water-repellent material that prevents rainwater from entering the interior of the housing 102. The sealant only needs to be positioned between the edge 170 and the component surface 134 along the entire circumference of the edge 170, and the width along the edge 170 is arbitrary.

[0031] Referring to Figure 6, as described above, a linear groove 136 is formed on the component side 134 (i.e., base portion 130) of the heat sink 104, and multiple (i.e., 12) heat-generating components 154 are attached by screws 166 (see Figure 5). Figure 6 is a cross-sectional view of the power converter 100 broken between the power conversion board 140 and the component side 134. Figure 6 can also be described as a front view of the power converter 100 with the front panel 110, control board 142, board fixing member 144 and power conversion board 140 removed. Figure 6 shows three sets of heat-generating components 154, with multiple (i.e., 4) heat-generating components 154 connected to circuits (not shown) formed on each of the three power conversion boards 140 shown in Figure 4. Referring to Figure 5, each heat-generating component 154 is connected to the circuit of the power conversion board 140 by lead wires 156 and solder or the like. On the component surface 134, each groove 136 is formed above (i.e., in the positive direction of the Z axis) the component placement area (see dashed-dotted line portion) where each set of heat-generating components 154 is attached. The grooves 136 have a predetermined depth and width. Each groove 136 is formed in a straight line sloping from the upper right to the lower left. That is, the grooves 136 are formed in a shape in the YZ plane such that the Z coordinate increases monotonically with respect to the Y coordinate. The grooves 136 can be formed, for example, by machining the component surface 134 of the heat sink 104.

[0032] As described above, when the power converter 100 is placed on the wall of the house, the heat sink 104 is positioned so that the component surface 134 is aligned with the vertical line (i.e., the Z-axis). That is, the heat sink 104 is positioned vertically such that the first side 134a of the rectangular component surface 134 is located above the vertical line, and the second side 134b opposite the first side 134a is located below the vertical line. Referring to Figure 7, the depth d and width W of the groove 136 are arbitrary. For example, the depth d is from 3 mm to 10 mm, and the width W is from 3 mm to 10 mm.

[0033] After the power converter 100 is installed on the wall of the house, if the caulking material 174 deteriorates over time, rainwater will seep into the housing 102, i.e., into the power converter 100, from the deteriorated portion. Referring to Figure 8, the small amount of water that has entered the power converter 100 flows as shown by the dashed arrow. That is, the invading water flows vertically downward along the component surface 134, and even when it reaches the upper edge 138 of the groove 136, it does not enter the groove 136 due to surface tension, but instead flows diagonally downward along the upper edge 138 on the component surface 134. After that, it flows vertically downward along the component surface 134 from the left end of the groove 136. This prevents the water that has entered the power converter 100 from the deteriorated portion of the caulking material 174 from coming into contact with the heat-generating component 154 attached to the component surface 134. In other words, the groove 136 functions as a suppression part. Therefore, it is possible to prevent the heat-generating component 154 from being affected by rainwater and being damaged.

[0034] If only a small amount of water enters, it will naturally dry as it flows vertically downward along the component surface 134, and the heat generated by the heat-generating component 154 is transferred to the base portion 130, causing the temperature of the component surface 134 to rise. The water flowing vertically downward along the component surface 134 will accumulate due to surface tension at the stepped portion formed by the edge portion 170 and the component surface 134 (see the dashed-dotted line portion shown in Figure 8). If the amount of water increases and it can no longer accumulate, it will flow along the rear panel 112 and accumulate on the bottom panel 116. Therefore, for example, if drainage holes are provided in the bottom panel 116, the water that has entered can be discharged to the outside of the power converter 100.

[0035] Furthermore, if water that has entered the power converter 100 and reached the upper edge 138 of the groove 136 enters the groove 136, the water will flow diagonally downwards within the groove 136 towards the left end. After that, the water will exit the groove 136 from the left end and flow vertically downwards on the component surface 134. Therefore, just as if the water were flowing diagonally downwards along the upper edge 138 on the component surface 134, contact with the heat-generating component 154 attached to the component surface 134 can be suppressed.

[0036] As described above, the power converter 100 includes a housing 102 and a heat sink 104, and the heat dissipation fins 132 of the heat sink 104 are configured to be located outside the housing 102, thereby efficiently cooling the electronic components (i.e., heat-generating components 154) inside the housing 102. Furthermore, by providing grooves 136 on the component surface 134 of the base portion 130, even if rainwater enters the power converter 100 due to deterioration of the sealant, etc., it is possible to suppress water contact with the heat-generating components 154 attached to the component surface 134, thereby preventing damage to the heat-generating components 154.

[0037] The above describes the case where all of the multiple part surfaces 134 are formed diagonally from the upper right to the lower left. In this case, forming grooves is the simplest machining method, but the process is not limited to this. At least one of the multiple grooves may be formed diagonally from the upper left to the lower right.

[0038] The above describes the case where the groove is formed in a straight line on the component surface 134, but it is not limited to this. The groove may also be formed in an arc shape on the component surface 134. That is, when the component surface 134 is positioned along a vertical line, the vertical height of the groove should be monotonically increasing or decreasing from the first end to the second end of the groove. This allows water that has entered the interior of the housing 102 from the connection between the housing 102 and the heat sink 104 to move along the groove formed on the component surface 134 and flow to an area where no electronic components (i.e., heat-generating components 154) are located. Therefore, damage to the electronic components by water can be prevented.

[0039] (First variation) In the above, the case in which a linear groove 136 is formed on the component surface 134 of the heat sink 104 is described, as shown in Figures 6 and 8, but the invention is not limited to this. Referring to Figure 9, the heat sink 180 according to the first modified example is formed in the same way as the heat sink 104, including a base portion and heat dissipation fins. The only difference between the heat sink 180 and the heat sink 104 is that each of the multiple grooves 200 formed on the component surface 182 of the base portion is formed in a V-shape with two line segments connected to each other at their ends. The grooves 200 are grooves of a predetermined depth and width, similar to the grooves 136. The heat sink 180 is fixed to the edge portion 170 of the housing 102 by screws, similar to the heat sink 104, and a sealant is placed between the housing 102 and the component surface 182 of the heat sink 180. In addition, a heat-generating component 154 is attached to the component surface 182 of the heat sink 180 by screws. Figure 9 shows the edge 170 of the rear panel 112 and the heat-generating component 154 with dashed lines when the heat sink 180 is attached to the housing 102.

[0040] Figure 9 shows the XYZ axes defined based on each surface constituting the housing 102, as described above, when the heat sink 180 is attached to the housing 102 and a power converter similar to the power converter 100 shown in Figure 1 is configured. The groove 200 is formed such that, in the YZ plane, point A, which is the point with the maximum Z coordinate among the points located between the ends of the groove 200, is designated as a specific point, and the Z coordinate monotonically increases from the left end of the groove 200 to the specific point A, and then monotonically decreases from the specific point A to the right end of the groove 200. When the power converter with the groove 200 attached to the housing 102 is placed on the wall of a house, the positive direction of the Z axis becomes vertically upward. If the caulking material deteriorates over time, rainwater will enter the inside of the housing 102 from the deteriorated part. In that case, as in Figure 8, the invading water can be directed along the upper edge of the groove 200 towards either the left or right end. Water that reaches the end of the groove 200 (i.e., the right or left end) flows vertically downward from the end along the component surface 182. This prevents water that has entered the power converter through deteriorated parts of the sealant from coming into contact with the heat-generating component 154 attached to the component surface 182. In other words, the groove 200 functions as a suppression mechanism. Therefore, the heat-generating component 154 can be prevented from being damaged by rainwater.

[0041] Note that Figure 9 shows a case where point A is located in the center of the groove 200 in the left-right direction, and the Z coordinates of the left end and right end of the groove 200 are equal, that is, the groove 200 is symmetrical with respect to a line along the Z axis passing through point A, but is not limited to this. The groove 202 may have a shape where point A is at any position between the left end and the right end of the groove 200. Also, the Z coordinates of the left end and the right end of the groove 200 may be different. It is sufficient that the Z coordinate of point A is greater than either the Z coordinate of the left end or the Z coordinate of the right end of the groove 200. At least one of the grooves 200 shown in Figure 9 may be replaced by the groove 202 shown in Figure 10. Figure 10 shows the XYZ axes when the groove 202 is formed on the component surface (i.e., base part) of the heat sink, similar to Figure 9, and shows a specific point A in the YZ plane that has the largest Z coordinate among the points located between the two ends of the groove 202. In groove 202, the Z-coordinate of point A is greater than the Z-coordinate of point B located at the left end of groove 200 and the Z-coordinate of point C located at the right end. When the power converter, with the heat sink having groove 202 formed therein attached to the housing 102, is placed on the wall of a house, the positive direction of the Z-axis is above the vertical line. If the caulking material deteriorates over time, rainwater will enter the power converter 100 from the deteriorated portion. In that case, as in Figure 8, the invading water can be directed along the upper edge of groove 202 towards either the left or right end. Water that reaches the end of groove 202 (i.e., the right or left end) flows vertically downward from the end along the component surface. This prevents water that has entered the power converter from the deteriorated portion of the caulking material from coming into contact with the heat-generating components attached to the component surface of the heat sink.

[0042] Furthermore, the grooves are not limited to linear or combined linear shapes as shown in Figures 6, 8 to 10. As shown in Figure 11, the groove 204 may be arc-shaped. Figure 11 shows the XYZ axes as in Figure 10, and indicates a specific point A in the YZ plane that is located between the two ends of the groove 204 and has the maximum Z coordinate. The groove 204 is formed such that the Z coordinate increases monotonically from the left end of the groove 204 to the specific point A, and decreases monotonically from the specific point A to the right end of the groove 204. When a power converter with a heat sink having the groove 204 formed thereon is mounted on a housing 102 is placed on the wall of a house, the positive direction of the Z axis is above the vertical line. Therefore, as described above, when rainwater enters the inside of the power converter 100, the water can flow along the upper edge of the groove 204 towards either the left or right end. Water that reaches the end of the groove 204 (i.e., the right or left end) flows vertically downward from the end along the surface of the component. This prevents water that has entered the power converter through deteriorated areas of the sealant from coming into contact with the heat-generating components attached to the heat sink's component surface.

[0043] In Figure 11, point A is located in the center of the groove 204, and the Z coordinates of the left end and right end of the groove 204 are equal, that is, the groove 204 is symmetrical with respect to a line along the Z axis passing through point A. However, the figure is not limited to this. Point A can be located anywhere between the left and right ends of the groove 204. Also, the Z coordinates of the left end and right end of the groove 204 may be different. If the Z coordinate of point A is greater than either the Z coordinate of the left end or the Z coordinate of the right end of the groove 204, the water that has entered the power converter can be drained as described above, and contact of the heat-generating component 154 attached to the component surface of the heat sink can be suppressed.

[0044] In other words, if the groove formed on the component surface 134 is not formed in an inclined straight line (see Figure 6), then when the component surface 134 is positioned along a vertical line, the vertical height of the groove should have a shape in which it monotonically increases from the first end of the groove to a specific point A, and then monotonically decreases from point A to the second end. This allows water that has entered the housing 102 from the connection between the housing 102 and the heat sink to move along the groove and flow to areas where no electronic components are placed, thereby preventing damage to the electronic components by water.

[0045] (Second variation) The above describes the case where grooves are located only on the upper side of the heat-generating component, but the invention is not limited to this. Referring to Figure 12, the heat sink 184 according to the second modification is formed similarly to the heat sinks 104 and 180, including a base portion and heat dissipation fins. The only difference between the heat sink 184 and the heat sinks 104 and 180 is that each of the multiple grooves 206 formed on the component surface 186 of the base portion is formed by an arc-shaped (i.e., semi-arc-shaped) portion (see groove 204 in Figure 11) and vertical portions 208 extending from both ends thereof. The grooves 206 are grooves of a predetermined depth and width, similar to grooves 136 and 200. The component surface 186 is fixed to the housing 102 by screws, similar to the heat sink 104, and a sealant is placed between the housing 102 and the component surface 186 of the heat sink 184. In addition, the heat-generating component 154 is attached to the component surface 186 of the heat sink 184 by screws. Figure 12 shows the edges 170 of the rear panel 112 and the heat-generating components 154 with dashed lines when the heat sink 184 is attached to the housing 102. The two vertical portions 208 that make up each groove 206 are attached to the component surface 186 with screws and are located on both sides of a set (i.e., four) of heat-generating components 154 mounted on each power conversion board 140.

[0046] Figure 12, like Figures 9 and 10, shows the XYZ axes and a specific point A in the YZ plane that is located in the arc portion and has the maximum Z coordinate. When the power converter with the heatsink 184 attached to the housing 102 is placed on the wall of a house, the positive direction of the Z axis is vertically upward. If the caulking material deteriorates over time, rainwater will enter the housing 102 from the deteriorated part. In that case, as in Figure 8, the water that has entered can be directed along the upper edge of the groove 206 towards either the left or right end. The water that reaches the end of the groove 206 (i.e., the right end or the left end) flows from the end along the component surface 186 in the direction of gravity (i.e., the negative direction of the Z axis). This prevents water that has entered the power converter from the deteriorated part of the caulking material from coming into contact with the heat-generating component 154 attached to the component surface 186. Therefore, it is possible to prevent the heat-generating component 154 from being damaged by rainwater. The groove 204 includes a groove 206 that extends vertically from the arc-shaped portion, ensuring that water that enters the housing flows reliably through areas where the heat-generating component 154 is not located, thereby preventing the heat-generating component 154 from being damaged by water.

[0047] The arc-shaped portion of groove 204 shown in Figure 12 (see groove 204 in Figure 11) may be replaced by groove 200 shown in Figure 9 or groove 202 shown in Figure 10. In the case of such grooves, as with groove 206 shown in Figure 12, water that enters the housing can be reliably directed to flow through areas where the heat-generating component 154 is not located, thereby preventing the heat-generating component 154 from being damaged by water.

[0048] (Third variation) The above describes a case in which multiple grooves are formed on the component surface of the heat sink, but is not limited to this. Referring to Figure 13, the heat sink 188 according to the third modified example is formed in the same way as the heat sink 184, including a base portion and heat dissipation fins. The difference between the heat sink 188 and the heat sink 184 is that one groove 210 is formed on the component surface 190 of the base portion. That is, the groove 210 is formed by a portion where three arcs are connected and a vertical portion 212 extending from the connected portion of the arcs. The groove 210 can be described as a shape formed by combining the three grooves 206 shown in Figure 12, that is, a shape in which the vertical portions 208 of adjacent grooves 206 are combined to form a vertical portion 212 (a shape in which adjacent arc portions share a vertical portion 212). The groove 210, like the groove 206, is a groove of a predetermined depth and width. The component surface 190, like the component surface 186, is fixed to the housing 102 by screws, and sealant is placed between the housing 102 and the component surface 190 of the heatsink 188. In addition, the heat-generating components 154 are attached to the component surface 190 of the heatsink 188 by screws. In Figure 13, the edge 170 of the rear panel 112 and the heat-generating components 154 are shown by dashed lines when the heatsink 188 is attached to the housing 102. Each vertical portion 212 constituting the groove 210 is attached to the component surface 190 by screws and is located on either side of a set (i.e., 4) of heat-generating components 154 mounted on each power conversion board 140.

[0049] Figure 13, like Figure 12, shows the XYZ axes and indicates a specific point A in the YZ plane that has the maximum Z coordinate among points located in one arc portion (i.e., the rightmost arc portion). When the power converter with the heatsink 188 attached to the housing 102 is placed on the wall of a house, the positive direction of the Z axis is vertically upward. If the caulking material deteriorates over time, rainwater will enter the inside of the housing 102 from the deteriorated part. In that case, as with Figure 8, the water that has entered can be flowed in either the left or right direction along the upper edge of the arc-shaped portion of the groove 210 by surface tension. Water that flows on the component surface 190 and reaches the end of the groove 210, i.e., the lower end of the vertical portion 212 at the right or left end, continues to flow on the component surface 190 in the direction of gravity (i.e., the negative direction of the Z axis). On the other hand, water that reaches the connecting part of the arc of an adjacent groove 210 enters the groove 210 from the connecting part and flows through the vertical portion 212. When water reaches the lower end of the vertical portion 212, it exits the groove 210 and flows along the component surface 190 in the direction of gravity. This prevents water that has entered the power converter through deteriorated portions of the sealant from coming into contact with the heat-generating component 154 mounted on the component surface 190. Therefore, damage to the heat-generating component 154 due to rainwater can be prevented. In the groove 210, adjacent arc-shaped portions share the vertical portion 212, ensuring that water that has entered the housing flows through areas where the heat-generating component 154 is not located, thereby preventing damage to the heat-generating component 154 by water.

[0050] The above primarily describes the case where water flows along the upper edge of a groove on a component surface due to surface tension. When the amount of water entering increases, surface tension is insufficient to hold the water at the upper edge of the groove, and the water enters the groove and flows through it. Therefore, the groove may be formed in such a way that the water that enters actively flows into it. For example, referring to Figure 14, the groove 214 formed on the component surface 134 of a heat sink has an inclined surface 220 on its upper edge. The inclined surface 220 can be formed by forming the groove 136 shown in Figure 7 on the component surface 134 and then chamfering the upper corner of the groove 136 by cutting it at an angle. If the angle θ that the inclined surface 220 makes with the component surface 134 is obtuse (i.e., an angle greater than 90 degrees), then if the component surface 134 is positioned vertically, water flowing from above the component surface 134 will easily enter the groove 214. If the shape of the groove 214 in the YZ plane is formed in the same way as the grooves shown in Figures 6, 9 to 13, then water that enters the groove 214 will flow through it. Therefore, it is possible to prevent heat-generating components attached to the component surface 134 from being affected by rainwater and being damaged. By forming an inclined surface 220 that forms an obtuse angle with respect to the component surface 134 on the upper part of the peripheral edge defining the groove 214, water that has entered the housing can easily enter the groove 214 and flow to areas where no electronic components are placed, thereby preventing damage to electronic components by water.

[0051] In the above, grooves formed on the component surface allow water to flow while avoiding electronic components mounted on the component surface, but the invention is not limited to this. Protrusions may also be formed on the component surface. This allows water that has entered the housing 102 to move along the protrusions and flow to areas where no electronic components are located, preventing damage to the electronic components by water. For example, referring to Figure 15, a protrusion 222 may be formed by filling the groove 136 shown in Figure 6 with a water-repellent material (e.g., caulking material). That is, the protrusion 222 is formed in an inclined straight line within the component surface 134 (i.e., the YZ plane), similar to the groove 136 shown in Figure 6. Therefore, similar to Figure 8, water that has entered the housing can be moved along the upper part of the protrusion 222 by surface tension and flow to areas where no electronic components are located, preventing damage to the electronic components by water. Protrusions can be easily formed by forming grooves 136 on the component surface 134 of the heat sink and filling the grooves 136 with a water-repellent material. Furthermore, it is sufficient if the protrusions can be formed with high positional accuracy on the component surface of the heat sink, and the protrusions may be formed by directly applying a water-repellent material to the component surface without forming grooves on the component surface.

[0052] The above describes a case where grooves or protrusions are formed on the component surface of the heat sink, but is not limited to this. By forming a step on the component surface of the heat sink, water that has entered the housing can be moved along the step by surface tension. For example, referring to Figure 16, a step 224 may be formed on the component surface 134 of the base portion 130 of the heat sink. Of the component surface 134, the component placement area 230 is the area where electronic components that will be damaged if they come into contact with water are placed, and the non-component placement area 232 is the area where no electronic components are placed. A step 224 is formed at the boundary between the component placement area 230 and the non-component placement area 232. The shape of the step 224 in the YZ plane may be, for example, a shape that slopes toward its end (right end, left end, or both ends), as shown in Figures 6 and 9 to 13. When the heat sink is positioned such that the component surface 134 is aligned with a vertical line, the component placement area 230 is located below the vertical line, and the non-component placement area 232 is located above the vertical line, the heat sink will have a step 224 that creates a step in the vertical direction (i.e., the Z-axis direction). As a result, water flowing from above over the non-component placement area 232 will reach the step 224 and flow along the step 224. Therefore, it is possible to prevent water from coming into contact with the electronic components placed in the component placement area 230, thereby preventing damage to the electronic components by water.

[0053] Furthermore, referring to Figure 17, a step 226 may be formed on the component surface 134 of the base portion 130 of the heat sink, with the opposite shape of the irregularities compared to Figure 16. The step 226 is formed at the boundary between the component placement area 230 and the non-component placement area 232. The shape of the step 226 in the YZ plane may be, for example, as shown in Figures 6 and 9 to 13, a shape that slopes toward its ends (right end, left end, or both ends). When the component surface 134 of the heat sink is aligned with a vertical line, the component placement area 230 is located below the vertical line, and the non-component placement area 232 is located above the vertical line, the heat sink will have a step in the vertical direction (i.e., the Z-axis direction) due to the step 226. As a result, when a small amount of water flowing from above over the non-component placement area 232 reaches the step 226, surface tension causes the water to flow along the corner of the step 226. Therefore, it is possible to prevent water from coming into contact with the electronic components placed in the component placement area 230, and to prevent the electronic components from being damaged by water.

[0054] The above describes how, with respect to power converters, the electronic components inside the casing can be efficiently cooled and damage to the electronic components can be prevented even if water enters the casing, but the disclosure is not limited to this. This disclosure can also be applied to electronic devices other than power converters, including electronic components that are heat-generating components and heat sinks on which said electronic components are mounted.

[0055] The present disclosure has been described above by describing embodiments, but the embodiments described above are illustrative and the present disclosure is not limited to the embodiments described above. The scope of the present disclosure is given by the claims, with reference to the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wording contained herein. [Explanation of Symbols]

[0056] 100 Power Converters 102 cabinets 104, 180, 184, 188 heatsinks 110 Front Panel 112 Rear Panel 114 Top panel 116 Bottom Panel 118 Left side panel 120 Right side panel 130 Base section 132 heat dissipation fins 134, 182, 186, 190 Component side 134a First side 134b Second side 136, 200, 202, 204, 206, 210, 214 groove 138 Upper edge 140 Power Conversion Board 142 Control board 144 Substrate fixing member 150, 152 spacers 154 Heat-generating components 156 Lead wire 160, 162, 164, 166 screws 170 Edge 172 Aperture 174 Caulking material 208, 212 Vertical section 220 Slope 222 Convex part 224, 226 steps 230 Component placement area 232 Parts non-placement area Points A, B, and C

Claims

1. The casing and A heat sink is mounted to the housing such that the heat dissipation portion is located outside the housing and the component side is located inside the housing, Includes an electronic component mounted on the aforementioned component surface, The connection between the heat sink and the housing is waterproofed. The heat sink is arranged vertically such that the first side of the component surface is located above the vertical line, and the second side of the component surface opposite the first side is located below the vertical line. On the component surface, a suppression portion is formed above the component placement area where the electronic component is mounted, to suppress the intrusion of water into the component placement area. The suppression portion includes a protrusion that extends from the surface of the component, The electronic device includes a water-repellent member disposed within a groove so as to protrude from a groove formed on the surface of the component.

2. The electronic device according to claim 1, wherein the groove has a step in the vertical direction.

3. The electronic device according to claim 1, wherein the upper portion of the peripheral edge defining the groove has a surface formed at an obtuse angle with respect to the component surface.

4. The electronic device according to any one of claims 1 to 3, wherein the groove includes a vertical portion extending vertically outside the component placement area.

5. Multiple grooves are formed on the surface of the component, The electronic device according to claim 4, wherein the vertical portion is shared by the adjacent groove.

6. The groove has a vertical height of, The groove has a shape that is monotonically increasing or decreasing from the first end to the second end, or The electronic device according to any one of claims 1 to 3, having a shape that is monotonically increasing from the first end to a specific point located between the first end and the second end, and monotonically decreasing from the specific point to the second end.

7. A group of electronic components that perform power conversion, Circuit board and Includes the electronic device described in any one of claims 1 to 3, The aforementioned group of electronic components and the circuit board are located within the housing of the electronic device. The group of electronic components includes the electronic components mounted on the component surface of the heat sink, The electronic component mounted on the component surface of the heat sink is a power converter mounted on the circuit board.

8. Heat dissipation section, Including the component surface on which electronic components are mounted, On the component surface, a suppression portion is formed outside the component placement area where the electronic component is mounted, to suppress the intrusion of water into the component placement area. The suppression portion includes a protrusion that extends from the surface of the component, The heat sink includes a water-repellent member disposed within a groove so as to protrude from a groove formed on the surface of the component.

Images