Electronic device

Abstract

To provide an electronic device which enables water entering from a heat radiation hole of a top plate to be drained to the outside of a housing while providing the heat radiation hole on the top plate to enable efficient heat radiation.SOLUTION: An electronic device (1) includes: a heating element (71); a housing (2) in which the heating element (71) is installed and which includes a top plate (40) provided with a heat radiation hole (2a) and a side plate (42) provided with a drain hole (2b); a heat sink (9) in which a heat radiation part (90) which contacts with the heating element (71) to radiate heat and a water receiving part (100) which is located below the heat radiation hole (2a), includes an end at the opposite side of the side connected to the heat radiation part (90) protrudes to the outside of the drain hole (2b), and receives water entering from the heat radiation hole (2a) to guide the water to the drain hole (2b) are integrally formed; and a fan (110) which blows air from an upper surface (91) of the heat radiation part (90) toward the heat radiation hole (2a) and the drain hole (2b) through an upper surface (101) of the water receiving part (100).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to electronic devices. [Background technology]

[0002] Conventionally, electronic devices that are designed to prevent water from above from coming into contact with electric / electronic components are known. For example, Patent Document 1 describes an in-vehicle device as an electronic device, in which an intake port for taking in cooling air and an exhaust port for discharging the cooled air are provided on the bottom plate of a housing that stores electric / electronic components, thereby preventing water and dust from entering the housing through the intake port and the exhaust port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-110640 A Summary of the Invention [Problem to be solved by the invention]

[0004] By the way, high-temperature air tends to rise. Therefore, in order to efficiently dissipate heat from electronic devices, it is preferable to provide heat dissipation holes in the top plate of the housing. However, when heat dissipation holes are provided in the top plate, there is a problem that water may enter the housing through the heat dissipation holes and come into contact with the electronic components inside the housing. The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an electronic device that has a heat dissipation hole in the top plate to enable efficient heat dissipation, while also being able to drain water that enters through the heat dissipation hole in the top plate to the outside of the housing. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, the electronic device of the present invention is an electronic device that dissipates heat by air cooling, and is characterized in that it comprises a heat-generating element, a housing having a top plate in which the heat-generating element is installed and which has a heat dissipation hole, and a side plate which has a drainage hole, a heat dissipation section which is in contact with the heat-generating element and dissipates heat from the heat-generating element, and a water receiving section which is formed and connected to the heat dissipation section, is located below the heat dissipation hole, and has an end opposite to the side connected to the heat dissipation section which protrudes outside the drainage hole, and receives water that enters through the heat dissipation hole and guides it to the drainage hole, a heat sink which is integrally constructed with these, and a fan that blows air from the upper surface of the heat dissipation section via the upper surface of the water receiving section toward the heat dissipation hole and the drainage hole. Effect of the Invention

[0006] According to the present invention, since the heat dissipation holes are provided in the top plate, the property of high-temperature air rising can be utilized to quickly discharge the high-temperature air to the outside of the housing, and heat can be efficiently dissipated. Also, even if water enters through the heat dissipation holes in the top plate, the water can be received by the water receiving part of the heat sink and guided to the drainage hole, and the water can be drained outside the housing by inclining the water receiving part or by making the air blowing force of the fan sufficiently strong. Therefore, according to the present invention, it is possible to provide an electronic device that can drain water entering through the heat dissipation holes in the top plate to the outside of the housing while providing heat dissipation holes in the top plate to enable efficient heat dissipation. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view of an in-vehicle device according to a first embodiment, as viewed obliquely from above. [Diagram 2] 1 is a perspective view of an in-vehicle device according to a first embodiment, viewed obliquely from below. [Diagram 3] 1 is a perspective view of an in-vehicle device according to a first embodiment with a top case and a front cover removed therefrom. [Figure 4] 2 is a perspective view showing a rear side plate of the in-vehicle device according to the first embodiment. FIG. [Diagram 5] 2 is a cross-sectional view taken along line VV in FIG. 1. [Figure 6] 4 is an enlarged view of the periphery of a water receiving portion of the heat sink according to the first embodiment. FIG. [Figure 7] 11 is an enlarged view of the periphery of a water receiving portion of a heat sink according to a second embodiment. FIG. [Figure 8] 13 is an enlarged view of the periphery of a water receiving portion of a heat sink according to embodiment 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [1. Configuration of Electronic Device According to First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings.

[0009] Fig. 1 is a perspective view of an in-vehicle device 1 according to embodiment 1 as viewed obliquely from above, and Fig. 2 is a perspective view of the same in-vehicle device 1 as viewed obliquely from below. In this embodiment, a vehicle-mounted device 1 will be described as an example of an electronic device. In this embodiment, the vehicle-mounted device 1 will be described as being basically installed on a horizontal plane. In this embodiment, when referring to the front, rear, left and right of the vehicle-mounted device 1, the vehicle-mounted device 1 in FIG. 1 will be used as a reference. That is, the front side of the vehicle-mounted device 1 will be described as corresponding to the lower left side in FIG. 1, and the rear side of the vehicle-mounted device 1 will be described as corresponding to the upper right side in FIG. 1. In addition, the left side of the vehicle-mounted device 1 will be described as corresponding to the upper left side in FIG. 1, and the right side of the vehicle-mounted device 1 will be described as corresponding to the lower right side in FIG. 1.

[0010] The in-vehicle device 1 is a device mounted on a vehicle, such as an infotainment device, an audio device, or a navigation device. The in-vehicle device 1 includes a housing 2 that defines the exterior shape. The housing 2 is formed from an appropriate material, such as metal or resin, with a shape (a rectangular parallelepiped shape in the illustrated example) and dimensions that fit into an installation space in the vehicle. The installation space may be, for example, a storage recess provided in the dashboard of the vehicle, but if the device does not have a display unit or an operation panel, it may be embedded in an invisible location inside the dashboard of the vehicle. The size of this installation space is, for example, 1DIN or 2DIN size standard of German Industrial Standards.

[0011] FIG. 3 is a perspective view of the in-vehicle device 1 according to the first embodiment with the top case 4 and the front cover 5 removed. As shown in Figures 1 and 3, the in-vehicle device 1 of this embodiment has a bottom case 3 arranged below, circuit boards 6, 7 housed in the bottom case 3, heat sinks 8, 9 installed on the circuit boards 6, 7, a fan unit 10 arranged above the lower heat sink 8, a top case 4 closing the bottom case 3 from above and covering the circuit boards 6, 7, the heat sinks 8, 9 and the fan unit 10, and a front cover 5 covering the front surfaces of the bottom case 3 and the top case 4.

[0012] The bottom case (first member) 3 is in the shape of a shallow box with an open top. The bottom case 3 in this embodiment has a rectangular flat bottom plate portion (bottom plate) 30 (see FIG. 2), and a front plate portion 31, a rear plate portion 32, a left plate portion 33, and a right plate portion 34 corresponding to side plate portions provided on the front, rear, left, and right sides of the bottom plate portion 30.

[0013] The top case (second member) 4 is in the shape of a deep box with an open bottom. As shown in Fig. 1, the top case 4 of this embodiment has a rectangular flat top plate portion (top plate) 40 and side plates provided on the front, rear, left and right sides of the top plate portion 40. The side plates are composed of a front plate portion 41 (see Fig. 5), a rear plate portion (side plate) 42, a left plate portion 43, and a right plate portion 44.

[0014] The front cover (third member) 5 covers the front plate portion 31 of the bottom case 3 and the front plate portion 41 of the top case 4. The front cover 5 of the present embodiment has an outer front plate portion 51 that constitutes a front side plate together with the front plate portion 41 of the top case 4, and a top plate connection portion 50 that bends rearward from the upper end of the front plate portion 51.

[0015] The housing 2 of this embodiment is constituted by the bottom case 3, the top case 4, the front cover 5, and the rear cover 52 (see FIG. 4). That is, the front plate 31, the rear plate 32, the left plate 33, and the right plate 34 of the bottom case 3 are connected to the front plate 41, the rear plate 42, the left plate 43, and the right plate 44 of the top case 4, respectively, and the front plate 51 and the top plate connection part 50 of the front cover 5 are connected to the front plate 31 of the bottom case 3 and the front plate 41 of the top case 4, and the top plate 40 of the top case 4, respectively, to constitute the hollow housing 2.

[0016] In this embodiment, the front plate portion 31, the front plate portion 41, and the front plate portion 51 form the front side plate of the housing 2. The rear plate portion 32, the rear plate portion 42, and the rear cover 52 form the rear side plate of the housing 2. The left plate portion 33 and the left plate portion 43 form the left side plate of the housing 2. The right plate portion 34 and the right plate portion 44 form the right side plate of the housing 2. The top plate of the housing 2 is formed by the top plate portion 40 and the top plate connection portion 50. The bottom plate of the housing 2 is formed by the bottom plate portion 30.

[0017] An air intake 35 is formed in the bottom plate of the housing 2, i.e., the bottom plate portion 30 of the bottom case 3 (see FIG. 2). The air intake 35 is composed of a plurality of round holes. In the present embodiment, the air intake 35 is formed at a position facing the heat generating element 61 (see FIG. 5) of the lower circuit board 6.

[0018] FIG. 4 is a perspective view showing a rear side plate of the in-vehicle device 1 according to the first embodiment. A plurality of heat dissipation holes 2a are formed in the top plate of the housing 2, i.e., the top plate portion 40 of the top case 4. The heat dissipation holes 2a are formed on the outer periphery of the top plate portion 40. In this embodiment, the heat dissipation holes 2a are formed at the rear end portion. The heat dissipation holes 2a are formed in the shape of elongated holes extending in the front-rear direction. A plurality of heat dissipation holes 2a are formed in the left-right direction, and together they form a heat dissipation port. In this embodiment, the heat dissipation holes 2a are formed from the top plate portion 40 to the rear plate portion 42 of the top case 4. That is, in this embodiment, the heat dissipation holes 2a are formed in the top plate portion 40 and the rear plate portion 42 of the top case 4.

[0019] Drainage holes 2b are formed in the side surface of the housing 2 in a position corresponding to the lower side of the heat dissipation holes 2a. In this embodiment, the drainage holes 2b are formed in the rear side panel of the housing 2. The drainage holes 2b are openings that extend horizontally. The drainage holes 2b are formed to be longer in the left-right direction than the formation range of the heat dissipation holes 2a. In this embodiment, a lower edge portion 42a that is recessed upward is formed in the rear panel portion 42 of the top case 4. The drainage hole 2b is formed by the surrounding shape of the lower edge portion 42a of the rear panel portion 42 and a tip end 102 in the extension direction of a water receiving portion 100 described later.

[0020] Connector holes 2c are formed in the side surface of the housing 2 in a position corresponding to the lower side of the heat dissipation holes 2a. In this embodiment, a plurality of connector holes 2c are appropriately formed in the rear side plate of the housing 2. The connector holes 2c are formed lower than the drainage holes 2b. In this embodiment, some of the connector holes 2c and the drainage holes 2b form an integral opening shape.

[0021] FIG. 5 is a cross-sectional view taken along line VV in FIG. Circuit boards 6 and 7 are disposed inside the housing 2. The circuit boards 6 and 7 are, for example, printed circuit boards. The circuit boards 6 and 7 are disposed vertically with a gap therebetween. The circuit boards 6 and 7 are fixed to the bottom case 3 or the top case 4. The lower circuit board 6 has a board 60 installed over substantially the entire surface of the bottom plate portion 30 as shown in FIG. 3. The upper circuit board 7 has a board 70 formed in a shape so as to avoid the fan unit 10. The boards 60 and 70 are mounted with electric and electronic components 61, 62, 63, 64, 65, 66, 71, 72, 73, 74, etc., required for the in-vehicle device 1 as shown in FIGS. 3 to 5. The boards 60 and 70 have a large number of components disposed on their mounting surfaces for implementing various functions of the in-vehicle device 1.

[0022] These components include heat generating elements 61 and 71, which generate more heat than other components and require heat dissipation for stable operation. Examples of the heat generating elements 61 and 71 include processors such as MPUs (Micro Processing Units) and CPUs (Central Processing Units), and various integrated circuits such as SoCs (System-on-a-Chips) and PICs (Peripheral Interface Controllers). In this embodiment, the heat generating element 61 is an SoC. The heat generating element 71 is a PIC.

[0023] The upper board 60 and the lower board 70 are electrically connected by a harness 62 . Appropriate connectors 63, 64, 65, 66, 73, and 74 (see FIG. 4) are provided at the rear ends of the boards 60 and 70. External terminals extending from external devices are removably connected to the connectors 63, 64, 65, 66, 73, and 74. The connectors 63, 64, 65, 66, 73, and 74 protrude to the outside of the housing 2 through the connector holes 2c.

[0024] Heat sinks 8 and 9 are attached to the heating elements 61 and 71, respectively. The lower surfaces of the heat sinks 8 and 9 are attached to the upper surfaces of the heating elements 61 and 71 via thermally conductive grease or a thermally conductive sheet. As a result, the heat sinks 8 and 9 receive heat from the heating elements 61 and 71. The thermally conductive grease or the thermally conductive sheet may be omitted. The heat sinks 8 and 9 absorb the heat from the heating elements 61 and 71 and release the heat to the surrounding air. As a result, the heat sinks 8 and 9 release the heat generated by the heating elements 61 and 71 by air cooling. The heat sinks 8 and 9 are formed of a highly thermally conductive material such as aluminum, copper, or an aluminum alloy. In this embodiment, the heat sink 8 is an aluminum plate, and the heat sink 9 is aluminum die-cast.

[0025] The lower heat sink 8 is formed into an L-shape in cross section as shown in Fig. 5. The heat sink 8 has a plate-shaped main body 80 that has a thickness in the up-down direction and extends in the front-rear direction, and a plate-shaped bent portion 81 that bends upward from the front end of the main body 80. The lower surface of the main body 80 of the heat sink 8 is in close contact with the upper surface of the heating element 61.

[0026] A fan unit 10 is disposed above the lower heat sink 8. The fan unit 10 has a fan 110 and an air duct 120 that supports the fan 110. The air duct 120 is fixed to the inner surface of the top panel portion 40. The fan 110 is fixed to the lower surface of the air duct 120.

[0027] In this embodiment, an axial flow fan is used as the fan 110. The fan 110 has a rectangular ring-shaped fan casing 110a, a fan motor 110b supported on the inner periphery of the fan casing 110a, and blades (not shown) rotatably supported by the fan motor 110b. The fan casing 110a is fixed to the lower surface of the air duct 120 by fasteners such as bolts. The fan 110 rotates around a motor shaft of the fan motor 110b extending in the vertical direction as the center of rotation. The fan 110 sucks in air from below and blows it upward. The type of the fan 110 may be other than an axial flow fan, such as a sirocco fan.

[0028] The air duct 120 guides air blown by the fan 110 to the heat sink 9. The air duct 120 has a plate-like main body 121 having a thickness in the vertical direction. The main body 121 is flat and extends at an angle to the left as it progresses rearward (see FIG. 3). A ventilation hole 121a penetrating in the vertical direction is formed at the front end of the main body 121. The fan 110 is fixed to the underside of the main body 121 in correspondence with the ventilation hole 121a. The fan 110 is disposed so as to cover the ventilation hole 121a. As a result, the fan 110 faces the main body 80 of the heat sink 8.

[0029] At this time, the bottom surface of the fan casing 110a is located lower than the upper end of the bent portion 81 of the heat sink 8. The bottom surface of the fan casing 110a is located lower than the upper substrate 70. This makes it easier for the fan 110 to send air flowing above the main body 80 of the heat sink 8 into the air duct 120 through the ventilation opening 121a.

[0030] A duct wall 122 (see FIG. 3) is formed on the upper surface of the main body 121 in a shape that stands up from the upper surface. In a plan view, the duct wall 122 has a front wall 123 extending in a semicircular arc shape along the left front side of the ventilation opening 121a, a left wall 124 extending left rear from the left end of the front wall 123, and a right wall 125 extending left rear from the right end of the front wall 123. On the upper surface of the main body 121, the front side, left side, and right side of the ventilation opening 121a are surrounded by the front wall 123, the left wall 124, and the right wall 125 of the duct wall 122. The left wall 124 and the right wall 125 extend rearward with a predetermined interval between them. An approximately U-shaped upper opening 122a that is open to the rear is formed by the surrounding shapes of the upper end of the front side wall 123, the upper end of the left side wall 124, and the upper end of the right side wall 125. The upper end of the duct wall 122 is configured to abut against or be close to the top plate portion 40. An approximately U-shaped rear opening 122b that is open upward is formed by the surrounding shapes of the rear end of the main body portion 121, the rear end of the left side wall 124, and the rear end of the right side wall 125.

[0031] A plurality of fixing parts 126 are formed on the outer periphery of the upper part of the duct wall 122 (see FIG. 3). The fixing parts 126 are fixed to the top plate part 40 of the top case 4. At this time, the upper opening 122a is closed by the top plate part 40, and the upper part of the rear opening 122b is also closed. That is, an air flow path 120S (see FIG. 5) is formed by the space surrounded by the duct wall 122 and the top plate part 40. In the air duct 120, air flowing in from the ventilation opening 121a flows through the flow path 120S and flows out from the rear opening 122b.

[0032] The front wall 123 has a lower portion 123a extending upward and an upper portion 123b that slopes left and rear as it advances upward from the upper end of the lower portion 123a. The sloped shape of the upper portion 123b makes it easier for the air flowing upward from the ventilation opening 121a to be guided left and rear without decreasing its flow speed.

[0033] A heat sink 9 is disposed behind the rear opening 120b of the air duct 120. The heat sink 9 extends from the air duct 120 toward the heat dissipation holes 2a. The heat sink 9 integrally includes a heat dissipation section 90 located above the heat generating element 71, and a water receiving section 100 connected to the heat dissipation section 90 and located below the heat dissipation holes 2a.

[0034] A pair of outer walls 111, 112 (see FIG. 3) are formed in the width direction on the upper surface of the heat sink 9, i.e., the upper surface 91 of the heat dissipation portion 90 and the upper surface 101 of the water receiving portion 100. The outer walls 111, 112 extend from the air duct 120 toward the heat dissipation hole 2a. The outer walls 111, 112, together with the upper surfaces 91, 101 of the heat dissipation portion 90 and the water receiving portion 100, form a recessed shape that is open upward.

[0035] The outer wall portions 111, 112 of the water receiving portion 100 are formed outside the heat dissipation holes 2a in the left-right direction. The outer wall portions 111, 112 are formed at a height that makes them abut or approach the top plate portion 40. An air flow path 9S is formed by a space surrounded by the upper surfaces 91, 101 of the heat dissipation portion 90 and the water receiving portion 100, the outer wall portions 111, 112, and the top plate portion 40. In the heat sink 9, air flowing out from the rear opening 120b of the air duct 120 flows through the flow path 9S and is discharged to the outside of the housing 2 through the heat dissipation holes 2a and the drainage holes 2b.

[0036] Hereinafter, the upstream side of the heat sink 9 refers to the air duct 12 side of the heat sink 9. The downstream side of the heat sink 9 refers to the heat radiation hole 2a side of the heat sink 9.

[0037] 5, the heat dissipation section 90 has a block-shaped base section 92. The base section 92 extends from the air duct 120 toward the heat dissipation hole 2a. A heat receiving section 93 formed in a rectangular column shape is formed on the lower surface of the base section 92. The lower surface of the heat receiving section 93 is in close contact with the upper surface of the heating element 71.

[0038] A duct connection portion 94 is formed at the upstream end of the base portion 92. The duct connection portion 94 protrudes downward from the base portion 92 and then protrudes forward. The duct connection portion 94 extends below the air duct 120.

[0039] The upper surface of the base portion 92, i.e., the upper surface 91 of the heat dissipation portion 90, has an upstream upper surface 91a that slopes upward as it advances downstream. In other words, the distance between the upstream upper surface 91a and the top plate portion 40 narrows as it advances downstream. The upstream end of the upstream upper surface 91a is formed at the same height as the upper surface of the main body portion 121 of the air duct 120. The upstream end of the upstream upper surface 91a may be lower than the upper surface of the main body portion 121. This makes it easier for the air discharged from the air duct 120 to move to the upper surface 91 of the heat dissipation portion 90.

[0040] A midstream upper surface 91b is formed on the downstream side of the upstream upper surface 91a, extending along the top plate portion 40. The midstream upper surface 91b is located above the heat receiving portion 93. A downstream upper surface 91c is formed on the downstream side of the midstream upper surface 91b, which slopes upward as it proceeds downstream.

[0041] A connector avoidance portion 95 is formed at the downstream end of the base portion 92. The connector avoidance portion 95 is cut out in an L-shape. The connector avoidance portion 95 accommodates the connectors 73, 74 (see FIGS. 3 and 4).

[0042] A plurality of heat dissipating fins 96 are formed on the upper surface 91 and are erected thereon. The heat dissipating fins 96 are formed between the outer wall portions 111, 112. The heat dissipating fins 96 are arranged at predetermined intervals in the left-right direction. The cross section of the heat dissipating fin 96 has a generally trapezoidal shape that tapers upward. The heat dissipating fin 96 extends so as to incline to the left as it proceeds rearward. Note that in FIG. 5, the heat dissipating fins 96 are illustrated to be spaced apart in the front-rear direction in order to show a cross section intersecting with the inclined heat dissipating fin 96.

[0043] 6 is an enlarged view of the periphery of the water receiving portion 100 of the heat sink 9 according to the embodiment 1. FIG 6 is an enlarged view of the main part of FIG. A water receiving portion 100 is formed downstream of the heat dissipation portion 90, connected to the heat dissipation portion 90 and located below the heat dissipation hole 2a. The water receiving portion 100 is a plate-like member having a smaller thickness than the heat dissipation portion 90. The water receiving portion 100 extends rearward. The water receiving portion 100 is formed so as to be wider than the area of ​​the heat dissipation hole 2a in a plan view. A tip 102 in the extension direction of the water receiving portion 100 penetrates the drainage hole 2b and protrudes rearward of the housing 2. A protrusion amount L1 of the tip 102 of the water receiving portion 100 protruding from the outer surface of the housing 2 is formed smaller than a protrusion amount L2 of the nearby connectors 73 and 74. In this embodiment, the protrusion amount L1 of the water receiving portion 100 is formed smaller than the protrusion amount of the connectors 63 to 66, 73, and 74.

[0044] In this embodiment, the upper surface 101 of the water receiving portion 100 is a flat surface that slopes backward (toward the drainage hole 2b) as it extends downward. The distance between the upper surface 101 of the water receiving portion 100 and the upper edge of the drainage hole 2b, i.e., the lower edge portion 42a of the rear plate portion 42 (see FIG. 4), is formed to be large enough so that water flowing over the upper surface 101 of the water receiving portion 100 does not touch the lower edge portion 42a.

[0045] In this embodiment, the heat dissipation section 90 and the water receiving section 100 in the heat sink 9 can be defined based on the highest part (in other words, the part where the distance between the top plate section 40 and the upper surfaces 91, 101 is narrowest) of the upper surface shape formed by the parts other than the heat dissipation fins 96 and the outer wall sections 111, 112, i.e., the upper surface 91 of the heat dissipation section 90 and the upper surface 101 of the water receiving section 100. That is, in the heat sink 9, the highest part is formed so as to intersect with the flow path 9S. The highest part connects between the outer wall section 111 and the outer wall section 112. The part of the heat sink 9 on the heat dissipation hole 2a side of the highest part constitutes the water receiving section 100. Also, the part of the heat sink 9 other than the water receiving section 100 constitutes the heat dissipation section 90.

[0046] In this embodiment, the embankment portion 113 is formed by the highest part. The embankment portion 113 is formed upstream of the heat dissipation hole 2a. The embankment portion 113 can easily prevent the water received by the water receiving portion 100 from entering the air duct 120. The embankment portion 113 in this embodiment has a top 113a which is the highest part, an embankment wall surface 113b formed on the water receiving portion 100 side of the top 113a and having a steep shape approximately perpendicular to the upper surface 101 of the water receiving portion 100, and an embankment slope surface 113c formed on the heat dissipation portion 90 side of the top 113a and sloping upward from the upstream to the downstream.

[0047] The embankment wall surface 113b makes it easier to prevent water from the water receiving portion 100 from entering the air duct 120 even if the vehicle body tilts and the in-vehicle device 1 tilts. The bank slope 113c extends flush from the downstream upper surface 91c. The bank slope 113c allows air to easily flow downstream while maintaining its momentum without being disturbed by the bank portion 113. Therefore, the air is easily drained by the blowing air from the fan 110.

[0048] [2. Functions of electronic devices] Next, the operation of the first embodiment will be described. When the in-vehicle device 1 is operated and the fan 110 is operated, an air flow A (see Figs. 5 and 6) is generated that moves from the intake hole of the bottom case 3 toward the heat dissipation hole 2a and the drainage hole 2b of the top case 4. That is, the air taken in from the intake port 35 moves along the lower surface of the lower circuit board 6, detouring the outer periphery of the lower circuit board 6 toward the fan unit 10. The air moving toward the fan unit 10 cools the heat sink 8 below.

[0049] The air that has cooled the heat sink 8 is taken in by the fan 110 of the fan unit 10 and sent to the flow path 120S of the air duct 120. The air sent to the flow path 120S is guided to the upper surface 91 of the heat sink 9 above, and flows along the heat dissipation fins 96, whereby it is heated by the heat dissipation section 90 and becomes hot. The hot air is discharged from the heat dissipation holes 2a and the drainage holes 2b. In this embodiment, since the heat dissipation holes 2a are formed in the top plate section 40, the tendency of high-temperature air to rise can be utilized to quickly discharge the high-temperature air, enabling efficient heat dissipation.

[0050] Here, in this embodiment, water may enter the housing 2 through the heat dissipation holes 2a. In particular, the in-vehicle device 1 may be installed below an air conditioner, a defroster, or the like or their piping, and in that case, condensation water may enter through the heat dissipation holes 2a. In this embodiment, when water enters the inside of the housing 2 through the heat dissipation holes 2a, the entering water is received by the water receiving portion 100 of the heat sink 9 located below the heat dissipation holes 2a. That is, as shown by the arrow B1 in FIG. 6, the water that drops from the heat dissipation holes 2a is received by the upper surface 101 of the water receiving portion 100.

[0051] The water received in the water receiving portion 100 moves toward the drainage hole 2b as shown by the arrow B2 (see FIG. 6) due to the inclined shape of the upper surface 101 and the airflow A generated by the fan 110 if the airflow force of the fan 110 is sufficiently strong, and is drained from the drainage hole 2b to the outside of the housing 2. In particular, in this embodiment, the flow path 120S of the air duct 120 and the flow path 9S of the heat sink behind the fan 110 are closed or substantially closed, and the wind flows to the water receiving portion 100 with force without being dispersed. Therefore, the water is drained from the drainage hole 2b to the outside of the housing 2 by the air blown by the fan 110. Therefore, the water that has entered the inside of the housing 2 is drained using the heat sink 9 without touching the electric and electronic components 61-66, 71-74 of the circuit boards 6 and 7. Note that even if the airflow force of the fan is not sufficient, the invaded water is drained from the drainage hole 2b to the outside of the housing 2 due to the inclined shape of the upper surface 101.

[0052] [3. Effects] As described above, in this embodiment, the in-vehicle device 1 is an in-vehicle device 1 that dissipates heat by air-cooling, and is equipped with a housing 2 that includes a heat generating element 71, a top plate portion 40 in which the heat generating element 71 is installed and which has a heat dissipation hole 2a provided therein, and a rear plate portion 42 which has a drainage hole 2b provided therein, a heat dissipation portion 90 that is in contact with the heat generating element 71 and dissipates heat from the heat generating element 71, and a heat sink 9 that is integrally constructed with a water receiving portion 100 that is formed and connected to the heat dissipation portion 90, is located below the heat dissipation hole 2a, and has an end portion opposite to the side connected to the heat dissipation portion 90 that protrudes out of the drainage hole 2b, and receives water that enters through the heat dissipation hole 2a and guides it to the drainage hole 2b, and a fan 110 that blows air from upper surfaces 91, 101 of the heat dissipation portion 90 via the upper surfaces 91, 101 of the water receiving portion 100 toward the heat dissipation holes 2a and the drainage hole 2b. According to this configuration, since the heat dissipation holes 2a are provided in the top plate 40, the property of high-temperature air rising can be utilized to quickly discharge the high-temperature air to the outside of the housing 2, and heat can be efficiently dissipated. Even if water infiltrates through the heat dissipation holes 2a in the top plate 40, the water can be received by the water receiving portion 100 of the heat sink 9 and guided to the drainage holes 2b, and the water can be drained to the outside of the housing 2 by inclining the water receiving portion or by making the air blowing force of the fan 110 sufficiently strong. Therefore, according to the present invention, it is possible to provide an in-vehicle device 1 that can drain water infiltrating through the heat dissipation holes 2a in the top plate 40 to the outside of the housing 2 while enabling efficient heat dissipation by providing the heat dissipation holes 2a in the top plate 40.

[0053] In this embodiment, the water receiving portion 100 is provided with a slope that descends from the heat dissipation portion 90 side toward the drainage hole 2b side. According to this configuration, the water received in the water receiving portion 100 can be efficiently drained.

[0054] In this embodiment, the heat sink 9 includes a bank portion 113 between the heat dissipation portion 90 and the water receiving portion 100 for preventing the water received by the water receiving portion 100 from entering the heat dissipation portion 90. According to this configuration, it is possible to prevent water from entering the heat dissipation portion 90 side, and it is possible to easily prevent water from coming into contact with the heating element 71.

[0055] In this embodiment, the heat dissipation section 90 side of the embankment section 113 has a planar shape extending from the upper surfaces 91, 101 of the heat dissipation section 90, or a shape that gently rises from the upper surface 91 of the heat dissipation section 90 toward the water receiving section 100 side, and the water receiving section 100 side of the embankment section 113 has a steep shape relative to the upper surface 101 of the water receiving section 100. According to this configuration, even if the in-vehicle device 1 is tilted so that the heat dissipation section 90 side is lower than the water receiving section 100 side, the shape of the embankment section 113 on the water receiving section 100 side makes it easy to prevent the water received by the water receiving section 100 from entering the heat dissipation section 90 side. In addition, the shape of the embankment section 113 on the heat dissipation section 90 side makes it easy to ensure the force of the wind from the heat dissipation section 90 to the water receiving section 100. Therefore, if the blowing force of the fan 110 is made sufficiently strong, the air blown by the fan 110 can be used to facilitate drainage.

[0056] In this embodiment, the bank portion 113 is provided on the heat dissipation portion 90 side, which is farther away from the drainage hole 2b than directly below the heat dissipation hole 2a. According to this configuration, the water receiving portion 100 is larger than the heat dissipation hole 2a, so that the water dropping from the heat dissipation hole 2a can be easily received by the water receiving portion 100, and even if the water splashes off the water receiving portion 100, it is difficult for the water to go over the bank portion 113.

[0057] In this embodiment, a connector 74 is arranged on the rear plate portions 42, 32, and the amount of protrusion L1 from the outer surface of the rear plate portions 42, 32 to the tip 102 of the water receiving portion 100 is smaller than the amount of protrusion L2 from the outer surface of the rear plate portions 42, 32 to the tip of the connector 74. This configuration makes it easy to prevent the heat sink 9 protruding from the housing 2 from interfering with other members, and makes it easy to install the in-vehicle device 1. That is, even in this embodiment, the in-vehicle device 1 can be installed using the same arrangement space as in the conventional case.

[0058] [4. Configuration of Heat Sink According to Second Embodiment] Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. In the description of the second embodiment, components having the same functions as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0059] FIG. 7 is an enlarged view of the periphery of the water receiving portion 100 of the heat sink 209 according to the second embodiment. The heat sink 209 according to the second embodiment differs from the heat sink 9 according to the first embodiment in that it has a downstream upper surface 291c and a bank portion 213 instead of the downstream upper surface 91c and the bank portion 113 according to the first embodiment.

[0060] In the heat sink 209 according to the second embodiment, the downstream upper surface 291c extends along the top plate portion 40 on the downstream end side.

[0061] The embankment portion 213 according to the second embodiment is formed in a rib shape that protrudes upward relative to the downstream upper surface 291c of the heat dissipation portion 90 and the upper surface 91 of the water receiving portion 100. That is, the embankment portion 213 of the present embodiment has, on the heat dissipation portion 90 side of the top portion 113a, an embankment wall surface 213c that is cut up substantially perpendicular to the downstream upper surface 291c of the heat dissipation portion 90.

[0062] [5. Effect of the Second Embodiment] In this embodiment, as in embodiment 1, a vehicle-mounted device 1 can be provided that has a heat dissipation hole 2a in the top plate portion 40 to enable efficient heat dissipation, while also being able to drain water that enters through the heat dissipation hole 2a in the top plate portion 40 to the outside of the housing 2.

[0063] At this time, in the present embodiment as well, as in the first embodiment, the embankment 213 can prevent water from entering the heat dissipation section 90 side, and can prevent water from coming into contact with the heat generating element 71.

[0064] [6. Configuration of Heat Sink According to Third Embodiment] Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. In the description of the third embodiment, components having the same functions as those in the first and second embodiments are given the same reference numerals, and the description thereof will be omitted.

[0065] FIG. 8 is an enlarged view of the periphery of the water receiving portion 100 of the heat sink 309 according to the third embodiment. The heat sink 309 according to the third embodiment differs from the heat sink 209 according to the second embodiment in that it has a downstream upper surface 391c and an embankment portion 313 instead of the downstream upper surface 291c and the embankment portion 213 according to the second embodiment.

[0066] In the heat sink 309 according to the third embodiment, the downstream upper surface 391c extends along the top plate portion 40 on the downstream end side.

[0067] The embankment 313 according to the third embodiment is formed in a stepped shape with respect to the upper surface 101 of the water receiving part 100. The embankment 313 of the present embodiment has a top extension wall surface 313c of the same height as the top 113a on the heat dissipation part 90 side of the top 113a. The top extension wall surface 313c is connected flush with the downstream upper surface 391c.

[0068] [7. Effect of the Third Embodiment] In this embodiment, as in embodiments 1 and 2, a vehicle-mounted device 1 can be provided that has a heat dissipation hole 2a in the top plate portion 40 to enable efficient heat dissipation, while also being able to drain water that enters through the heat dissipation hole 2a in the top plate portion 40 to the outside of the housing 2.

[0069] At this time, in the present embodiment as well, as in the first and second embodiments, the embankment 313 can prevent water from entering the heat dissipation section 90 side, and can prevent water from coming into contact with the heat generating element 71.

[0070] 8. Other embodiments The above-described embodiment merely shows one aspect of the present invention, and any modification and application are possible within the scope of the present invention.

[0071] In the above embodiment, a configuration has been described in which a slope is provided on the upper surface 101 of the water receiving portion 100 to guide water to the drainage hole 2b. Although this configuration is preferable, the upper surface 101 of the water receiving portion 100 does not necessarily have to have a slope to guide water to the drainage hole 2b. In other words, a configuration may be used in which the blowing force of the fan is made sufficiently strong so that water is guided to the drainage hole 2b only by the airflow A generated by the fan 110.

[0072] In the above embodiment, the heat dissipation hole 2a is formed in the rear of the top plate 40, and the drainage hole 2b is formed in the rear plate 42. However, the positions of the heat dissipation hole 2a and the drainage hole 2b are not limited to the rear. That is, instead of the rear plate 42, the drainage hole 2b may be provided in any of the front plate 41, the left plate 43, and the right plate 44 depending on the position of the heat dissipation hole 2a. Although the housing 2 is preferably configured in a rectangular parallelepiped shape, the housing does not have to be rectangular. If the housing is not rectangular, the drainage hole may be provided in any position of the side plate connecting the outer periphery of the top plate and the outer periphery of the bottom plate.

[0073] [9. Summary of the present invention] The present invention will be summarized below.

[0074] (Configuration 1) An electronic device that dissipates heat by air cooling, comprising: a housing including a heat-generating element, the heat-generating element being installed inside the housing, the housing including a top plate having a heat dissipation hole, and a side plate having a drainage hole; a heat dissipation section that is in contact with the heat-generating element and dissipates heat from the heat-generating element; and a water receiving section that is connected to the heat dissipation section and is located below the heat dissipation hole, the end opposite to the side connected to the heat dissipation section protruding out of the drainage hole, and that receives water that enters through the heat dissipation hole and guides it to the drainage hole; and a fan that blows air from the upper surface of the heat dissipation section toward the heat dissipation hole and the drainage hole via the upper surface of the water receiving section. According to this configuration, since the heat dissipation holes are provided in the top plate, the tendency of high-temperature air to rise can be utilized to quickly discharge the high-temperature air to the outside of the housing, allowing efficient heat dissipation. Even if water enters through the heat dissipation holes in the top plate, the water can be received by the water receiving part of the heat sink and guided to the drainage hole, and the water can be drained outside the housing by using the inclination of the water receiving part or the air blown by the fan. Therefore, according to the above configuration, it is possible to provide an electronic device that can drain water entering through the heat dissipation holes in the top plate to the outside of the housing while providing heat dissipation holes in the top plate to enable efficient heat dissipation.

[0075] (Configuration 2) The electronic device according to configuration 1, wherein the water receiving portion is provided with a slope that descends from the heat dissipation portion side toward the drainage hole side. With this configuration, the water received in the water receiving portion can be efficiently drained.

[0076] (Configuration 3) The electronic device described in configuration 1 or 2, wherein the heat sink has a dike portion between the heat dissipation portion and the water receiving portion to prevent water received by the water receiving portion from entering the heat dissipation portion. According to this configuration, it is possible to prevent water from entering the heat dissipation portion side, and it is also possible to easily prevent water from coming into contact with the heat generating element side.

[0077] (Configuration 4) The electronic device described in configuration 3, wherein the heat dissipation section side of the embankment portion has a planar shape extending from the upper surface of the heat dissipation section, or a shape that gently rises from the upper surface of the heat dissipation section toward the water receiving section side, and the water receiving section side of the embankment portion has a steep shape relative to the upper surface of the water receiving section. With this configuration, the shape of the water receiving section side of the embankment makes it easy to prevent the water received by the water receiving section from entering the heat dissipation section side even if the electronic device is tilted so that the heat dissipation section side is lower than the water receiving section side. Also, the shape of the heat dissipation section side of the embankment makes it easy to ensure the force of the wind from the heat dissipation section to the water receiving section. Therefore, it is easy to drain the water by using the tilt of the water receiving section or the air blown by the fan.

[0078] (Configuration 5) The electronic device according to configuration 3 or 4, wherein the embankment portion is provided on the heat dissipation portion side, away from the drainage hole, rather than directly below the heat dissipation hole. According to this configuration, since the water receiving portion is larger than the heat dissipation hole, the water dropping from the heat dissipation hole can be easily received by the water receiving portion, and even if the water splashes off the water receiving portion, it is difficult for it to go over the bank portion.

[0079] (Configuration 6) An electronic device as described in any one of configurations 1 to 5, characterized in that a connector is arranged on the side plate, and the amount of protrusion from the outer surface of the side plate to the tip of the water receiving portion is smaller than the amount of protrusion from the outer surface of the side plate to the tip of the connector. With this configuration, it is easy to prevent the heat sink protruding from the housing from interfering with other components, making it easier to install the electronic device. [Explanation of symbols]

[0080] 1 In-vehicle equipment (electronic equipment) 2. Chassis 2a Heat dissipation hole 2b Drain hole 9. Heat sink 40 Top plate (top plate) 42 Rear plate (side plate) 63~66, 73, 74 Connectors 71 Heating element 90 Heat radiation part 91 Top surface 100 Water receiving part 101 Top surface 102 Tip 110 Fan 113, 213, 313 Embankment section L1 Water receiving part protrusion amount L2 Connector protrusion amount

Claims

1. An electronic device that dissipates heat by air cooling, A heating element; A housing in which the heat generating element is installed and which includes a top plate having a heat dissipation hole and a side plate having a drainage hole; a heat sink integrally comprising a heat dissipation section that contacts the heat generating element and dissipates heat from the heat generating element, and a water receiving section that is connected to the heat dissipation section and is located below the heat dissipation hole, the end of which on the opposite side to the side connected to the heat dissipation section protrudes outside the drainage hole, and the water receiving section receives water that has entered through the heat dissipation hole and guides it to the drainage hole; a fan that blows air from the upper surface of the heat dissipation portion through the upper surface of the water receiving portion toward the heat dissipation holes and the drainage holes; An electronic device comprising:

2. The water receiving portion is provided with a slope that descends from the heat dissipation portion side toward the drain hole side.

2. The electronic device according to claim 1 .

3. The heat sink includes a dike between the heat dissipation portion and the water receiving portion for preventing water received by the water receiving portion from entering the heat dissipation portion.

2. The electronic device according to claim 1 .

4. The heat dissipation portion side of the embankment has a planar shape extending from an upper surface of the heat dissipation portion, or a shape gradually rising toward the water receiving portion side with respect to the upper surface of the heat dissipation portion, The water receiving portion side of the bank portion has a steep shape with respect to the upper surface of the water receiving portion.

4. The electronic device according to claim 3.

5. The embankment portion is provided on the heat dissipation portion side away from the drainage hole rather than directly below the heat dissipation hole.

4. The electronic device according to claim 3.

6. A connector is disposed on the side plate, 2. The electronic device according to claim 1, wherein a protrusion amount from the outer surface of the side plate to the tip of the water receiving portion is smaller than a protrusion amount from the outer surface of the side plate to the tip of the connector.

Images