Electronic device

Abstract

To provide an electronic device which enables water entering from an intake port of a top plate to be drained to the outside of a housing with a simple structure while enabling air to be taken from the top plate to cool a heating element efficiently.SOLUTION: An electronic device (1) exhausts heat with air cooling. The electronic device (1) includes: a heating element (51); a housing (2) including a top plate (40) provided with an intake port (45), and a side plate (41) provided with an exhaust port (48) and a drain port (49) located below the exhaust port (48); a fan (90) facing the exhaust port (48) in the housing (2); and a heat sink (60) which is adhered to the heating element (51) in the housing (2), installed so as to cover the intake port (45), the exhaust port (48), the drain port (49), and the fan (90), and provided with an inner bottom surface (78) which causes water entering from the intake port (45) into an internal space (60S) to be drained from the drain port (49).SELECTED DRAWING: Figure 7

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] Generally, electronic devices tend to have a large space above them, so it is easy for cold air to be taken in from above. For this reason, from the viewpoint of cooling efficiency, it is desirable to provide an air intake on the top plate of the electronic device. However, when an air intake is provided on the top plate, as described above, there is a problem that water may enter the inside of the housing through the air intake. The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an electronic device that allows air to be drawn in from the top plate to efficiently cool heat-generating elements, while also draining water that enters through the air intake port on the top plate to the outside of the housing with a simple configuration. [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 with an air intake port in which the heat-generating element is installed, and a side plate with an air exhaust port and a drain port below the air exhaust port, a fan installed inside the housing facing the exhaust port and discharging air taken in from the air intake port to the exhaust port, and a heat sink installed inside the housing in close contact with the heat-generating element and covering the air intake port, the exhaust port, the drain port, and the fan, the heat sink having an inner bottom surface configured to discharge water that has entered the inner space from the air intake port through the drain port. Effect of the Invention

[0006] According to the present invention, since an air intake port is provided on the top plate, air can be drawn in from the top plate, and the heat generating elements can be efficiently cooled. Also, even if water enters through the air intake port on the top plate, the water can be received by the inner bottom surface of the heat sink and guided to the drain port, and the water can be drained outside the housing by utilizing the simple configuration of the heat sink shape. Therefore, according to the present invention, it is possible to provide an electronic device that can drain water that enters through the air intake port on the top plate to the outside of the housing with a simple configuration, while allowing air to be drawn in from the top plate to efficiently cool the heat generating elements. [Brief description of the drawings]

[0007] [Figure 1] 1 is a front view of an in-vehicle device according to an embodiment of the present invention; [Diagram 2] 1 is an exploded perspective view of an in-vehicle device according to an embodiment of the present invention; [Diagram 3] FIG. 1 is a perspective view of a heat sink according to an embodiment of the present invention. [Figure 4] FIG. 2 is a front view of the heat sink according to the embodiment. [Diagram 5] 5 is a cross-sectional view taken along line VV in FIG. 4. [Figure 6] 6 is a partial cross-sectional view corresponding to the cross section along the line VI-VI in FIG. [Figure 7]FIG. 7 is an enlarged view of a main part of FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [1. Configuration of electronic devices] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] FIG. 1 is a front view of an in-vehicle device 1 according to the present embodiment. In this embodiment, an in-car device 1 will be described as an example of an electronic device. In this embodiment, when referring to the front, rear, left and right of the in-car device 1, the in-car device 1 in Fig. 1 will be used as a reference. That is, the front side of the in-car device 1 will be described as corresponding to the front side of Fig. 1, and the rear side of the in-car device 1 will be described as corresponding to the back side of Fig. 1. In addition, the left and right of the in-car device 1 will be described as corresponding to the left and right of 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 there is no display unit or operation panel, the device may be embedded in an invisible location inside the dashboard of the vehicle. The size of this installation space is in accordance with the 1DIN or 2DIN size standard of the German Industrial Standard.

[0011] FIG. 2 is an exploded perspective view of the in-vehicle device 1 according to the present embodiment. The in-vehicle device 1 in this embodiment has a bottom case 3 arranged below, a circuit board 5 housed in the bottom case 3, a heat sink unit 6 arranged above the circuit board 5, and a top case 4 that closes the bottom case 3 from above and covers the circuit board 5 and the heat sink unit 6.

[0012] The bottom case (first member) 3 is a shallow box shape that is open at the top. The bottom case 3 of this embodiment has a rectangular flat bottom plate portion (bottom plate) 30, and a front plate portion (first side plate portion) 31, a rear plate portion 32, a left plate portion 33, and a right plate portion 34 that correspond 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 has a deep box shape with an open bottom. The top case 4 of the present embodiment has a rectangular flat top plate portion (top plate) 40, and a front plate portion (side plate) 41, a rear plate portion 42, a left plate portion 43, and a right plate portion 44 corresponding to the side plate portions provided on the front, rear, left and right sides of the top plate portion 40.

[0014] The bottom case 3 and the top case 4 form the housing 2 of this embodiment. 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, to form the hollow housing 2. In this embodiment, the front plate 31 and the front plate 41 form the front side plate of the housing 2. The rear plate 32 and the rear plate 42 form the rear side plate of the housing 2. The left plate 33 and the left plate 43 form the left side plate of the housing 2. The right plate 34 and the right plate 44 form the right side plate of the housing 2.

[0015] A circuit board 5 is disposed inside the housing 2. The circuit board 5 is, for example, a printed circuit board. The circuit board 5 is attached to the bottom case 3. The circuit board 5 has a board 50 that is installed over substantially the entire surface of the bottom plate portion 30. The board 50 is mounted with electric and electronic components 51 and 52 required for the in-vehicle device 1. A large number of components for implementing various functions of the in-vehicle device 1 are disposed on the mounting surface of the board 50. Among these components is a heat generating element 51 that generates more heat than other components and requires heat dissipation for stable operation. Examples of the heat generating element 51 include processors such as an MPU (Micro Processing Unit) and a CPU (Central Processing Unit), and various integrated circuits.

[0016] A heat sink unit 6 is in close contact with the heat generating element 51. The heat sink unit 6 absorbs heat from the heat generating element 51 and releases the heat to the surrounding air, thereby dissipating the heat generated by the heat generating element 51 through air cooling. The heat sink unit 6 includes a heat sink 60, a fan holder 80 fixed to the heat sink 60, and a fan 90 fixed to the fan holder 80.

[0017] Fig. 3 is a perspective view of the heat sink 60 according to the present embodiment. Fig. 4 is a front view of the heat sink 60 according to the present embodiment. Fig. 5 is a cross-sectional view taken along line VV in Fig. 4. The heat sink 60 is made of a highly thermally conductive material such as aluminum, copper, an aluminum alloy, etc. In this embodiment, the heat sink 60 is made of aluminum die-cast. The heat sink 60 has an appearance that is generally symmetrical and generally block-shaped.

[0018] The heat sink 60 has a base portion 61 that is rectangular in plan view. As shown in Figs. 4 and 5, a heat receiving portion 62 formed in a prismatic shape is formed on the lower surface of the base portion 61. The heat receiving portion 62 is formed biased to the left (one side in the left-right direction) with respect to the base portion 61 (see Fig. 4). A flat contact surface 62a is formed on the lower surface of the heat receiving portion 62. The contact surface 62a is in contact with the upper surface of the heat generating element 51. The contact surface 62a is in contact with the upper surface of the heat generating element 51 via thermally conductive grease or a thermally conductive sheet. As a result, the heat sink 60 receives heat from the heat generating element 51 via the heat receiving portion 62. The thermally conductive grease or the thermally conductive sheet may be omitted.

[0019] On the left and right sides of the heat receiving portion 62, columnar legs 63, 64 are formed which protrude downward. The legs 63, 64 protrude downward further than the heat receiving portion 62. The legs 63, 64 are provided offset in the front-rear direction. Fastening holes (not shown) for fastening fasteners 103 (see FIG. 2) are formed on the lower surfaces of the legs 63, 64. The legs 63, 64 come into contact with the circuit board 5 from above. As a result, the contact surface 62a is positioned at a height where it comes into contact with the upper surface of the heat generating element 51 of the circuit board 5 fixed to the bottom case 3.

[0020] An outer wall portion 65 is formed above the base portion 61. The outer wall portion 65 and the base portion 61 form a recessed shape that is open upward and forward. An inner space 60S of the heat sink 60 is formed by the portion surrounded by the base portion 61 and the outer wall portion 65.

[0021] The outer wall portion 65 has a rear wall portion 66 extending upward from the rear end of the base portion 61. As shown in Fig. 5, the rear wall portion 66 is formed with a lower end rear surface 66a that slopes forward as it proceeds upward from the rear end of the base portion 61, and an upper end rear surface 66b that extends upward in the vertical direction from the upper end of the lower end rear surface 66a.

[0022] A left wall portion 67 extending forward is formed at the left end of the rear wall portion 66. The left wall portion 67 extends upward from the left side end of the base portion 61. In this embodiment, the left wall portion 67 extends upward while being inclined slightly to the left as it proceeds upward (see FIG. 4). A holder fixing portion 67a is formed at the front end of the left wall portion 67. In this embodiment, the holder fixing portion 67a has a positioning pin 67b protruding forward and a fastening hole 67c formed above the positioning pin 67b. A sheet-shaped top board fixing portion 67d that protrudes leftward is formed above the left wall portion 67. The top board fixing portion 67d has an insertion hole that passes through in the vertical direction and through which a fastener 102 (see FIG. 2) is inserted.

[0023] A right wall portion 68 extending forward is formed at the right end of the rear wall portion 66. The right wall portion 68 extends upward from the right side end of the base portion 61. In this embodiment, the right wall portion 68 extends upward while being slightly inclined to the right as it proceeds upward (see FIG. 4). A holder fixing portion 68a is formed at the front end of the right wall portion 68. In this embodiment, the holder fixing portion 68a has a positioning pin 68b protruding forward and a fastening hole 68c formed below the positioning pin 68b. Therefore, in the holder fixing portion 68a of the right wall portion 68, the positions of the positioning pin 68b and the fastening hole 68c are upside down compared to the holder fixing portion 67a of the left wall portion 67. A piece-shaped top plate fixing portion 68d that protrudes to the right is formed above the right wall portion 68. The top plate fixing portion 68d has an insertion hole that passes through in the vertical direction and through which a fastener 102 (see FIG. 2) is inserted.

[0024] A plurality of heat dissipating fins 69 are arranged inside the enclosed shape of the outer wall portion 65, i.e., in the inner space 60S. The heat dissipating fins 69 are arranged at a predetermined interval in the left-right direction. The heat dissipating fins 69 are erected on the upper surface 61a of the base portion 61. The heat dissipating fins 69 are generally triangular prism-shaped and taper upward. The heat dissipating fins 69 extend in the front-rear direction. The heat dissipating fins 69 extend rearward from the holder fixing portions 67a, 68a and are connected to the front surface 66c of the rear wall portion 66.

[0025] In the heat sink 60, a triangular prism-shaped ventilation space 60S1 tapering downward is formed by each space surrounded by the base portion 61, the outer wall portion 65, and the heat dissipation fins 69. In other words, the inner space 60S is partitioned by the heat dissipation fins 69 to form each ventilation space 60S1. The upper and front surfaces of the ventilation space 60S1 are open.

[0026] A rib-shaped top plate adjacent portion 70 is formed above the heat dissipation fins 69 of the outer wall portion 65. The top plate adjacent portion 70 extends in an enclosure shape along the upper end shape of the outer wall portion 65. In this embodiment, the top plate adjacent portion 70 is substantially U-shaped with an open front in a plan view. In detail, the top plate adjacent portion 70 has a rear wall portion 71, a left wall portion 72, and a right wall portion 73 corresponding to the rear wall portion 66, the left wall portion 67, and the right wall portion 68. The top plate adjacent portion 70 is formed on the outside of the opening shape of the ventilation space 60S1 so as to form a step in the heat dissipation fins 69. The top plate adjacent portion 70 can abut against the top plate portion 40 of the top case 4 from below.

[0027] A front extension 74 is formed at the front end of the base 61, extending forward. The front extension 74 is formed in a flattened, generally U-shape when viewed from the front (see FIG. 4). In detail, the front extension 74 has a bottom 75 extending in the left-right direction, a left wall 76 protruding upward from the left end of the bottom 75, and a right wall 77 protruding upward from the right end of the bottom 75. As shown in FIG. 5, an upper surface 75a of the bottom 75 is recessed downward in a stepped shape with respect to an upper surface 61a of the base 61. A stepped surface 61b is formed between the upper surface 75a and the upper surface 61a, connecting the upper surface 75a and the upper surface 61a. The stepped surface 61b is located rearward of the front end of the outer wall 65. The front end of the front extension 74 can abut against the front plate 41 of the top case 4 from behind.

[0028] In this embodiment, the front surface 66c of the rear wall portion 66 is inclined forward (toward the drain outlet 49) as it advances downward. The upper surface 61a of the base portion 61 is inclined downward as it advances forward (toward the drain outlet 49). Furthermore, the upper surface 75a of the bottom surface portion 75 of the forward extension portion 74 is inclined downward as it advances forward (toward the drain outlet 49). The angle formed between the front surface 66c of the rear wall portion 66 and the upper surface 61a of the base portion 61 is an obtuse angle in a side view. The upper surface 61a of the base portion 61 and the upper surface 75a of the bottom surface portion 75 of the forward extension portion 74 are inclined at the same inclination with respect to the horizontal plane. The step surface 61b is inclined more steeply than the upper surfaces 61a and 75a. The inclination angle of the upper surfaces 61a and 75a with respect to the horizontal plane is preferably 1 degree or more and 2 degrees or less. The top surface 61a, the step surface 61b, and the top surface 71a form an inner bottom surface 78 of the heat sink 60 of the present embodiment.

[0029] Fig. 6 is a partial cross-sectional view corresponding to the cross section taken along line VI-VI in Fig. 1. Fig. 7 is an enlarged view of a main part of Fig. 6. As shown in FIGS. 2, 6, and 7, the heat sink 60 supports a fan holder 80 in the form of a curved plate. The fan holder 80 has a plate-shaped main body 81 having a thickness in the front-rear direction. The main body 81 is formed with a ventilation hole 81a penetrating in the front-rear direction. The ventilation hole 81a is formed at a position facing the front surface of the inner space 60S of the heat sink 60. Fixing parts 82, 83 are formed on the left and right of the ventilation hole 81a. The fixing parts 82, 83 are fixed to the holder fixing parts 67a, 68a of the heat sink 60, respectively. The fixing parts 82, 83 are formed with holes 82b, 83b into which the positioning pins 67b, 68b are fitted to be positioned, and an insertion hole 83c through which the fastener 100 is inserted (the insertion hole of the fixing part 82 is not shown). The fixing portions 82 and 83 are formed with fan fastening portions 83a (the fan fastening portion of the fixing portion 82 is not shown) to which the fastener 101 from the fan 90 is fastened.

[0030] An upper holder part 84 and a lower holder part 85 are formed at both the upper and lower ends of the main body part 81, each of which has a shape bent forward. The lower holder part 85 is formed so as to leave a predetermined gap δ with respect to the upper surface 75a of the forward extension part 74. The predetermined gap δ is a gap through which water can pass. In this embodiment, the vertical width of the gap δ is, for example, 2 mm. The vertical width of the gap δ may exceed 2 mm as long as it is sufficient to prevent the intrusion of foreign objects such as screws, and may be less than 2 mm as long as it does not impede the water flow.

[0031] The fan holder 80 supports the fan 90. In this embodiment, an axial fan is used for the fan 90. The fan 90 has a rectangular annular fan casing 91, a fan motor 92 supported on the inner periphery of the fan casing 91, and blades 93 rotatably supported by the fan motor 92. The fan casing 91 is fastened to a fan fastening portion 83a of the fan holder 80 with a fastener 101. This fixes the fan 90 to the fan holder 80. The type of fan 90 may be a type other than an axial fan, such as a sirocco fan. In this case, the shape of the fan holder is changed depending on the configuration of the fan.

[0032] Here, the top plate portion 40 of the top case 4 is formed with an intake port 45 penetrating in the vertical direction. The intake port 45 is formed at a position facing the upper surface of the inner space 60S of the heat sink 60. The intake port 45 is a rectangular opening having edges on the front, rear, left and right sides. The intake port 45 is formed to have an opening area smaller than the surrounding shape of the top plate adjacent portion 70. That is, the rear wall portion 71 of the top plate adjacent portion 70 is located behind the rear edge of the intake port 45. The left wall portion 72 of the top plate adjacent portion 70 is located to the left of the left edge of the intake port 45. The right wall portion 73 of the top plate adjacent portion 70 is located to the right of the right edge of the intake port 45. The air flowing in from the intake port 45 can flow into the ventilation space 60S1 of the inner space 60S of the heat sink 60.

[0033] Heat sink fastening parts 46, 47 that bulge downward are formed on the left and right sides of the intake port 45. Top plate fixing parts 67d, 68d of the heat sink 60 are fixed to the heat sink fastening parts 46, 47.

[0034] An exhaust port 48 is formed in the front plate portion 41 of the top case 4 at a position facing the front of the fan 90. The exhaust port 48 is formed by a plurality of openings 48a, 48b extending in an arc shape. In detail, as shown in FIG. 1, the exhaust port 48 has a plurality of openings 48a each having a shape obtained by dividing a small-diameter annular hole in the circumferential direction, and a plurality of openings 48b each having a shape obtained by dividing a large-diameter annular hole in the circumferential direction. The exhaust port 48 is formed facing the blades 93 of the fan 90. The exhaust port 48 is formed in an area smaller than the inner periphery of the fan casing 91.

[0035] A drain outlet 49 is formed below the exhaust outlet 48. The drain outlet 49 is a slit hole extending in the left-right direction. The drain outlet 49 is formed to be longer in the left-right direction than the left-right width of the exhaust outlet 48. The drain outlet 49 is also formed to be shorter than the left-right width of the bottom surface portion 75 of the forward extension portion 74. That is, the left wall portion 76 of the forward extension portion 74 is located to the left of the left end of the drain outlet 49. The right wall portion 77 of the forward extension portion 74 is located to the right of the right end of the drain outlet 49.

[0036] The upper edge of drain outlet 49 is located above upper surface 75a of bottom portion 75. The lower edge of drain outlet 49 is located below upper surface 75a of bottom portion 75. The distance between the upper and lower edges of drain outlet 49, i.e., vertical width 49W of drain outlet 49, is formed to a predetermined size. The predetermined size is a size that prevents foreign matter such as sand from entering the inside of housing 2 through drain outlet 49. In this embodiment, vertical width 49W is larger than the vertical width of gap δ. The predetermined size is, for example, about 2 mm.

[0037] A pair of left and right notches 31a are formed in the front plate 31 of the bottom case 3 by cutting out linearly downward. The notches 31a are formed further outward in the left-right direction than the drainage port 49 of the top case 4. In this embodiment, the notches 31a are formed further outward in the left-right direction than the forward extension 74. The notches 31a form a bent portion 31b that is bent in a raised shape inside the housing 2 on the upper side of the front plate 31. The bent portion 31b inclines backward as it advances upward. The bent portion 31b has a left-right width that is longer outward in the left-right direction than the forward extension 74.

[0038] The housing 2 is connected such that the front plate 31 of the bottom case 3 overlaps the inner surface of the front plate 41 of the top case 4. At this time, the drainage outlet 49 is located inside the left and right cutout portions 31a, 31a in the left-right direction. In addition, the bent portion 31b is located below the drainage outlet 49.

[0039] Next, an example of how to assemble the in-vehicle device 1 will be described. A fan holder 80 is fixed to the heat sink 60 by a fastener 100. A fan 90 is fixed to the fixed fan holder 80 by a fastener 101. In this manner, the heat sink unit 6 is formed. The heat sink unit 6 is fixed to the top panel 40 of the top case 4. In detail, fasteners 102 are inserted through top panel fixing portions 67d, 68d of the heat sink 60 from below, and the fasteners 102 are fastened to the heat sink fastening portions 46, 47 of the top panel 40.

[0040] At this time, the fan 90 of the heat sink unit 6 is disposed facing the exhaust port 48 of the top case 4. Furthermore, the upper end of the top plate adjacent portion 70 of the heat sink 60 of the heat sink unit 6 abuts against the inner surface of the top plate portion 40 behind, to the left, and to the right of the intake port 45 of the top case 4, and the front end of the forward extension portion 74 abuts against the inner surface of the front plate portion 41 near the drain port 49 of the top case 4. Thus, the heat sink 60 is installed so as to cover the intake port 45, the exhaust port 48, the upper edges of the drain port 49, and the fan 90.

[0041] The circuit board 5 is disposed in the bottom case 3. The circuit board 5 is fixed to the bottom case 3 by a plurality of fasteners. The bottom case 3 to which the circuit board 5 is fixed is closed by the top case 4 to which the heat sink unit 6 is fixed. At this time, the legs 63, 64 of the heat sink 60 are abutted against the board 50 of the circuit board 5, and the fasteners 103 are inserted from below the bottom case 3. Then, the fasteners 103 are fastened to the legs 63, 64, and the circuit board 5 and the bottom case 3 are fastened together to the legs 63, 64 of the heat sink unit 6. As a result, the contact surface 62a of the heat receiving portion 62 of the heat sink 60 is brought into close contact with the heat generating element 51. In this manner, the in-vehicle device 1 can be assembled. The fasteners 100 to 103 are bolts or screws.

[0042] [2. Function of the cooling device] Next, the operation of this embodiment will be described. When the in-vehicle device 1 is operated and the fan 90 is operated, the fan 90 exhausts air from the exhaust port 48. Thus, a negative pressure is applied to the ventilation space 60S1 of the heat sink 60, and air is taken into the ventilation space 60S1 of the heat sink 60 from the intake port 45 of the top plate portion 40. That is, in the ventilation space 60S1, an air flow A moving from the intake port 45 toward the exhaust port 48 is generated, and the heat dissipation fin 69 is air-cooled by this air flow A, and the air with an increased temperature is discharged from the exhaust port 48. In this embodiment, since the intake port 45 is formed in the top plate portion 40, cold air is easily taken in from the intake port 45, and the heat sink 60 is efficiently cooled. Therefore, the efficient cooling of the heat sink 60 efficiently dissipates heat from the heat generating element 51 in close contact with the heat sink 60.

[0043] Here, in this embodiment, water may enter through the air intake 45. 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, condensed water from these may enter through the air intake 45. In this embodiment, when water enters the inside of the housing 2 through the air intake 45, the invaded water passes through the inside of the surrounding shape of the top plate adjacent portion 70 and enters the inner space 60S of the heat sink 60. That is, as shown by the arrow B1 in FIG. 7, the water reaches the inner bottom surface 78 by running along the inner surface of the outer wall portion 65 of the heat sink 60 or the surface of the heat dissipation fin 69, or directly falls and reaches the inner bottom surface 78.

[0044] The water that reaches the inner bottom surface 78 moves toward the drain outlet 49 by the airflow A of the fan 90, as shown by the arrow B2 in FIG. 7. In particular, in this embodiment, the inner bottom surface 78 is inclined so that the drain outlet 49 side is downward, so that the water on the inner bottom surface 78 is easily guided to the drain outlet 49. The water on the inner bottom surface 78 that moves toward the drain outlet 49 passes through the gap δ between the fan holder 80 and the forward extension 74, and is drained from the drain outlet 49 to the outside of the housing 2, as shown by the arrow B3 in FIG. 7. Therefore, the water that has entered the inside of the housing 2 can be drained using the heat sink 60 without coming into contact with the electric and electronic components 51, 52 of the circuit board 5. In this embodiment, the water can pass through the gap δ below the fan holder 80, so that the fan 90 is also prevented from coming into contact with the water.

[0045] Even if water leaks downward between the forward extension 74 of the heat sink 60 and the front plate 41 of the housing 2, the downward bent portion 31b, which is longer in the left-right direction than the forward extension 74, allows the leaked water to be drained to the outside of the housing 2. Even when the fan 90 is stopped, the inclined shape of the inner bottom surface 78 of the heat sink 60 allows the water to be drained.

[0046] [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 includes a housing 2 having a heat generating element 51, a top plate portion 40 in which the heat generating element 51 is installed and in which an air intake 45 is provided, and a front plate portion 41 in which an air exhaust 48 is provided and in which a drain outlet 49 is provided below the air exhaust 48, a fan 90 installed inside the housing 2 facing the exhaust outlet 48 and discharging air taken in from the air intake 45 to the exhaust outlet 48, and a heat sink 60 installed inside the housing 2 in close contact with the heat generating element 51 and covering the air intake 45, the exhaust outlet 48, the drain outlet 49 and the fan 90, and the heat sink 60 having an inner bottom surface 78 configured to discharge water that has entered the inner space 60S from the air intake 45 through the drain outlet 49. According to this configuration, since the top plate portion 40 is provided with the air intake port 45, air can be taken in from the top plate portion 40, and the heat generating element 51 can be efficiently cooled. Even if water infiltrates from the air intake port 45 of the top plate portion 40, the water can be received by the inner bottom surface 78 of the heat sink 60 and guided to the drain port 49, and the water can be drained outside the housing 2 by utilizing the simple configuration of the shape of the heat sink 60. Therefore, according to this configuration, it is possible to provide an in-vehicle device 1 that can drain water that infiltrates from the air intake port of the top plate portion 40 to the outside of the housing 2 with a simple configuration, while allowing air to be taken in from the top plate portion 40 to efficiently cool the heat generating element 51.

[0047] In this embodiment, an incline is provided on the inner bottom surface 78 to guide water that has entered through the air intake 45 to the drain outlet 49. This configuration makes it easier to drain water from the inner bottom surface 78. Even if the fan 90 is stopped, the inclined shape of the inner bottom surface 78 of the heat sink 60 allows water to drain.

[0048] In this embodiment, heat dissipation fins 69 having a shape that does not impede the drainage of water that has entered through the air intake 45 to the drainage port 49 are provided in the inner space 60S of the heat sink 60. That is, in this embodiment, the heat dissipation fins 69 have a shape that extends in the front-rear direction, the top and front of the ventilation space 60S1 are open, and the shape does not impede the drainage of water from the ventilation space 60S1 of the inner space 60S. According to this configuration, water can be prevented from accumulating in the inner space 60S of the heat sink 60.

[0049] In this embodiment, the drainage hole 49 is a slit hole that extends along the inner bottom surface 78 of the heat sink 60 . According to this configuration, the slit holes allow the space above the inner bottom surface 78 to be connected to the outside of the housing 2 while making it difficult for the space to be blocked by the housing 2, making it easier to drain water on the inner bottom surface 78 to the outside of the housing 2.

[0050] In this embodiment, the housing 2 has a bottom case 3 that constitutes the bottom plate portion 30, and a top case 4 that is separate from the bottom case 3 and constitutes a front plate portion 41 in which an exhaust port 48 is provided, and the bottom case 3 has a front plate portion 31 that is bent to fit along the front plate portion 41 at least below the drain port 49 and is overlapped on the inside of the top case 4, and at least the upper edge of the front plate portion 31 below the drain port 49 is bent toward the inside of the housing 2. With this configuration, even if water leaks downward from between the front panel portion 41 and the forward extension portion 74 of the heat sink 60 at the drain outlet 49, the upper edge of the bent front panel portion 31, i.e., the bent portion 31b, makes it easy to drain the leaked water to the outside of the housing 2.

[0051] [4. 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.

[0052] In the above embodiment, a configuration has been described in which the inner bottom surface 78 is provided with a slope that guides water to the drain outlet 49. Although this configuration is preferable, the inner bottom surface 78 does not necessarily have to be provided with a slope that guides water to the drain outlet 49. In other words, a configuration in which water is guided to the drain outlet 49 only by the airflow A generated by the fan 90 may also be used.

[0053] In the above-described embodiment, a configuration is exemplified in which the upper surface 75a of the forward extension portion 74 of the inner bottom surface 78 is positioned above the lower edge of the drain outlet 49, but the upper surface 75a of the forward extension portion 74 may be at the same position as the lower edge of the drain outlet 49, or may be positioned below the lower edge of the drain outlet 49 within the acceptable range.

[0054] In the above embodiment, the exhaust port 48 is formed in the front plate portion 41, but the exhaust port 48 may be provided in any one of the rear plate portion 42, the left plate portion 43, and the right plate portion 44 instead of the front plate portion 41. Although the housing 2 is preferably configured in a rectangular parallelepiped shape, the housing does not have to be in a rectangular parallelepiped shape. If the housing is not in a rectangular parallelepiped shape, the exhaust port may be provided in any position of the side plate that connects the outer periphery of the top plate portion and the outer periphery of the bottom plate portion.

[0055] [5. Summary of the present invention] The present invention will be summarized below.

[0056] (Configuration 1) An electronic device that dissipates heat by air cooling, comprising: a heat-generating element; a housing having the heat-generating element installed inside and a top plate with an air intake, and a side plate with an air exhaust and a drain below the air exhaust; a fan installed inside the housing facing the air exhaust and discharging air taken in from the air intake to the air exhaust; and a heat sink installed inside the housing in close contact with the heat-generating element and covering the air intake, the air exhaust, the drain, and the fan, the heat sink having an inner bottom surface configured to discharge water that has entered the inner space from the air intake through the drain. According to this configuration, since the top plate is provided with an air intake port, air can be drawn in from the top plate, and the heat generating elements can be efficiently cooled. Also, even if water enters through the air intake port of the top plate, the water can be received by the inner bottom surface of the heat sink and guided to the drain port, and the water can be drained outside the housing by utilizing the simple configuration of the shape of the heat sink. Therefore, according to this configuration, it is possible to provide an electronic device that can drain water entering through the air intake port of the top plate to the outside of the housing with a simple configuration while allowing air to be drawn in from the top plate to efficiently cool the heat generating elements.

[0057] (Configuration 2) The electronic device according to configuration 1, wherein the inner bottom surface is provided with a slope for directing water that has entered through the air intake to the drain outlet. This configuration makes it easier to drain water from the inside bottom surface.

[0058] (Configuration 3) The electronic device according to configuration 1 or 2, characterized in that a heat dissipation fin having a shape that does not impede the drainage of water that has entered through the air intake to the drain outlet is provided in the inner space of the heat sink. This configuration can prevent water from accumulating in the inner space of the heat sink.

[0059] (Configuration 4) The electronic device according to any one of configurations 1 to 3, wherein the drain hole is a slit hole extending along the inner bottom surface of the heat sink. According to this configuration, the slit holes allow the space on the inner bottom surface to be connected to the outside of the housing while making it difficult for the space to be blocked by the housing, making it easier to drain water on the inner bottom surface to the outside of the housing.

[0060] (Configuration 5) The electronic device described in any of configurations 1 to 4, characterized in that the housing has a first member constituting a bottom plate and a second member constituting the side plate that is separate from the first member and has the exhaust port provided therein, the first member has a first side plate portion bent to fit along the side plate at least below the drain port and overlapped on the inside of the second member, and at least an upper edge of the first side plate portion below the drain port is bent toward the inside of the housing. With this configuration, even if water leaks downward from between the side plate and the heat sink at the drain outlet, the bent upper edge of the first side plate portion makes it easy for the leaking water to be drained outside the housing. [Explanation of symbols]

[0061] 1 In-vehicle equipment (electronic equipment) 2. Chassis 3 Bottom case (first part) 4 Top case (second part) 30 Bottom plate part (bottom plate) 31 Front plate portion (first side plate portion) 40 Top plate (top plate) 41 Front plate (side plate) 45 Air Intake 48 Exhaust port 49 Drain 51 Heating element 60 Heatsink 60S Inner Space 69 Heat dissipation fin 78 Inner bottom surface 90 Fans

Claims

1. An electronic device that dissipates heat by air cooling, A heating element; a housing having a top plate in which the heat generating element is installed and an intake port, and a side plate having an exhaust port and a drain port below the exhaust port; a fan that is installed inside the housing and faces the exhaust port and that exhausts air drawn in through the intake port to the exhaust port; a heat sink disposed inside the housing in close contact with the heat generating element and covering the intake port, the exhaust port, the drain port, and the fan, the heat sink having an inner bottom surface configured to discharge water that has entered an inner space from the intake port through the drain port; An electronic device comprising:

2. The inner bottom surface is provided with a slope that guides water that has entered through the air intake port to the drain port.

2. The electronic device according to claim 1 .

3. A heat dissipation fin having a shape that does not hinder the drainage of water that has entered through the air intake port to the drain port is provided in the inner space of the heat sink.

2. The electronic device according to claim 1 .

4. The drain hole is a slit hole extending along the inner bottom surface of the heat sink.

2. The electronic device according to claim 1 .

5. the housing has a first member constituting a bottom plate, and a second member constituting the side plate, the second member being separate from the first member and having the exhaust port provided therein; The first member has a first side plate portion bent at least below the drain outlet so as to follow the side plate and overlapped on the inside of the second member, At least an upper edge of the first side plate portion below the drain outlet is bent inwardly of the housing.

2. The electronic device according to claim 1 .

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