Vehicle-mounted electronic control device

Abstract

Provided is a vehicle-mounted electronic control device with which it is possible to reduce mounting restriction associated with entry of water into a housing. Specifically, a housing 3 is configured such that in one wall 4 among a plurality of walls, there are formed through holes 6A-6E through which connectors 5A-5F penetrate, air inflow holes 7, 8 for allowing air to flow into the housing 3 from the outside, and an air outflow hole 9 for allowing air to flow out from the housing 3 to the outside.

Description

In-vehicle electronic control device

[0001] The present invention relates to an in-vehicle electronic control device mounted on a vehicle.

[0002] With the evolution of vehicle electronic control technology in recent years, a large number of electronic control devices for controlling various functions are mounted on vehicles. These electronic control devices are also called ECUs (Electronic Control Unit). An ECU is a general term for a device (unit) that controls a system using an electronic circuit, mainly referring to those mounted on automobiles. Examples of ECUs include an engine ECU that controls an engine, a motor control ECU that controls a motor, a hybrid ECU that performs control for efficiently utilizing an engine and a motor, a transmission ECU that performs automatic control of shift changes, a power steering control ECU that controls power steering, a navigation ECU that performs control related to a navigation system, etc. And a vehicle can control various devices and systems related to the vehicle, such as an engine, a motor, brakes, an airbag, power steering, power windows, car navigation, and a key lock, by executing software incorporated in the ECU and further by coordinating each ECU via an in-vehicle network such as CAN.

[0003] These ECUs are mounted on a vehicle after being housed in a box-shaped casing. The ECU includes heat generating parts that generate heat during operation, such as a CPU, a GPU, and a SoC. In order not to reduce performance, it was important to appropriately cool those heat generating parts inside the casing. For example, Japanese Patent Application Laid-Open No. 2006-332154 proposes a technique of arranging a fan that generates an air flow near an air outflow hole of the casing, generating an air flow passing through the inside of the casing from an air inflow hole by the fan, and dissipating the heat generated by the heat generating parts to the outside of the casing by the air flow.

[0004] Japanese Patent Application Laid-Open No. 2006-332154 (paragraphs 0018 - 0030)

[0005] Here, in order to perform cooling using a fan as described in Patent Document 1 above, it is necessary to form air inlet holes for bringing in air from the outside and air outlet holes for releasing air to the outside in the wall surface of the housing that houses the ECU. Similarly, through holes must also be formed in the wall surface to expose connectors for connecting power cables and cables for communication with other ECUs to the outside of the housing. On the other hand, when the housing that houses the ECU is mounted in a vehicle, it was necessary to prevent, for example, condensed water or drainage from the vehicle's air conditioner from entering the housing through the air inlet holes, air outlet holes, through holes, etc. Therefore, in order to prevent the entry of water as described above, there was a problem that restrictions on the installation position and direction (mounting restrictions) of the housing that houses the ECU on the vehicle occurred, such as only being able to install it in a specific orientation.

[0006] The present invention was made to solve the aforementioned problems of the conventional invention, and aims to provide an in-vehicle electronic control device that can alleviate restrictions on mounting due to water ingress into the interior of the housing by forming air inlet holes, air outlet holes, and through holes, respectively, in one wall of the housing.

[0007] To achieve the above objective, the in-vehicle electronic control device according to the present invention comprises a fan that generates airflow when it operates, a circuit board on which electronic components and connectors are mounted, and a housing that is attached to a vehicle and has a plurality of walls that form an internal space housing the fan and the circuit board, wherein one of the plurality of walls of the housing has a through hole through which the connector passes, an air inlet for bringing air into the inside of the housing from the outside, and an air outlet for releasing air from the inside of the housing to the outside.

[0008] According to the in-vehicle electronic control device of the present invention having the above configuration, by forming air inlet holes, air outlet holes, and through holes in one wall of the housing, it becomes possible to alleviate restrictions on mounting that prevent water from entering the inside of the housing. As a result, when mounting the housing in a vehicle, it becomes possible to prevent condensed water and drainage from the in-vehicle air conditioner from entering the housing through the air inlet holes, air outlet holes, through holes, etc., while at the same time, the housing can be positioned in a relatively free position and orientation, improving the degree of freedom in the design of the interior of the vehicle.

[0009] This is an external perspective view of the in-vehicle electronic control device according to this embodiment when mounted horizontally. This is an external perspective view of the in-vehicle electronic control device according to this embodiment when mounted vertically. This is an external perspective view of the in-vehicle electronic control device according to this embodiment when mounted downwards. This is a magnified view of the area near the upper air inlet. This is an exploded perspective view of the in-vehicle electronic control device according to this embodiment. This is a diagram showing the heat dissipation fins according to this embodiment, and a diagram showing the fan according to this embodiment. This is a diagram showing the airflow generated by the fan for the in-vehicle electronic control device according to this embodiment. This is a diagram showing a first modified example of the in-vehicle electronic control device. This is a diagram showing a second modified example of the in-vehicle electronic control device. This is a diagram showing a third modified example of the in-vehicle electronic control device. This is a diagram showing a fourth modified example of the in-vehicle electronic control device. This is a diagram showing a fourth modified example of the in-vehicle electronic control device. This is a diagram showing a fourth modified example of the in-vehicle electronic control device.

[0010] The following will describe in detail an embodiment of the in-vehicle electronic control device according to the present invention, with reference to the drawings.

[0011] The on-board electronic control unit 1 is a device (unit) mounted on a vehicle that controls the vehicle's systems using electronic circuits. These on-board electronic control units 1, especially those mounted on vehicles, are also called ECUs (Electronic Control Units).

[0012] The vehicle on which the on-board electronic control unit 1 is installed may be, for example, an automobile powered by an internal combustion engine (internal combustion engine vehicle), an automobile powered by an electric motor (electric vehicle, fuel cell vehicle, etc.), or an automobile powered by both (hybrid vehicle). Furthermore, there are no restrictions on the type of vehicle; it may be a passenger car, a large commercial truck, a bus, etc. It may also be a forklift or construction machinery, as long as it has front and rear wheels. It may also be a two-wheeled or three-wheeled vehicle. The number and type of ECUs installed will differ depending on the type of vehicle.

[0013] Examples of ECUs include an engine ECU that optimally controls the amount of fuel injection and ignition timing required by the engine; a motor control ECU that controls the drive of the drive motor that serves as the power source in electric vehicles and hybrid vehicles; a hybrid ECU that controls the efficient use of the engine and drive motor in hybrid vehicles; a charge control ECU that controls the charging from the charging equipment to the vehicle in electric vehicles; a transmission ECU that controls the gear ratio to the optimal setting according to the vehicle's condition; a power steering control ECU that controls the power steering; and a navigation ECU that controls the navigation system.

[0014] The type of ECU corresponding to the on-board electronic control unit 1 in this embodiment may be any of the above-mentioned ECUs, or it may be an ECU of a different type, or any ECU that is installed in the vehicle. A vehicle will have a large number of on-board electronic control units 1 installed, corresponding to the number of ECUs. That is, there will be on-board electronic control units 1 corresponding to the engine ECU, on-board electronic control units 1 corresponding to the motor control ECU, on-board electronic control units 1 corresponding to the hybrid ECU, etc. Furthermore, the on-board electronic control units 1 do not necessarily have to be installed in the vehicle from the time of factory shipment, and may be newly installed after factory shipment.

[0015] Furthermore, the multiple ECUs installed in the vehicle are interconnected via an in-vehicle network such as CAN, sharing information and performing joint control.

[0016] [Appearance of the On-board Electronic Control Unit] Next, the appearance of the on-board electronic control unit 1 according to this embodiment will be described using Figures 1 to 3. Figure 1 is an external perspective view of the on-board electronic control unit 1 according to this embodiment when it is mounted in a predetermined orientation. Figure 2 is an external perspective view of the on-board electronic control unit 1 according to this embodiment when it is mounted in an orientation rotated 90 degrees from Figure 1. Figure 3 is an external perspective view of the on-board electronic control unit 1 according to this embodiment when it is mounted with the connector and air vents facing downwards. Hereafter, the orientation shown in Figure 1 will be referred to as horizontal, the orientation shown in Figure 2 as vertical, and the orientation shown in Figure 3 as downward.

[0017] As shown in Figures 1 to 3, the in-vehicle electronic control unit 1 according to this embodiment is entirely covered by a rectangular parallelepiped housing 3 so that electronic components and the like are not exposed to the outside. The housing 3 is molded from a resin material such as polyethylene, polypropylene, or ABS resin. However, it is not limited to being made of resin, and the housing 3 may be molded from metal in part or all. The in-vehicle electronic control unit 1 is mounted in the vehicle by fixing the housing 3 to a predetermined position inside the vehicle with screws, adhesive, or the like. The orientation in which the in-vehicle electronic control unit 1 is mounted in the vehicle is not particularly limited; it may be mounted horizontally as shown in Figure 1, vertically as shown in Figure 2, or downwards with the connectors and air vents on the bottom surface as shown in Figure 3. However, it is desirable to avoid mounting it with the connectors and air vents on the top surface.

[0018] Furthermore, the housing 3 is equipped with multiple walls (six if the housing 3 is a rectangular parallelepiped) that form an internal space. One of these walls 4 has through-holes 6A to 6E through which connectors 5A to 5F pass, upper air inlet holes 7 and lower air inlet holes 8 for allowing air to flow into the housing 3 from the outside, and air outlet holes 9 for allowing air to flow out from the inside of the housing 3 to the outside. In other words, in this embodiment, the through-holes 6A to 6E, the upper air inlet holes 7, the lower air inlet holes 8, and the air outlet holes 9 are all formed on the same surface of the housing 3. The connectors 5A to 5F are attached by soldering to the circuit board 15 located in the internal space of the housing 3, as described later, and are exposed to the outside through the through-holes 6A to 6E (see Figure 5).

[0019] In the examples shown in Figures 1 to 3, the through holes 6A to 6E, the upper air inlet 7, the lower air inlet 8, and the air outlet 9 are formed in wall 4, which is the second largest of the six walls of the housing 3. However, they can be formed in any wall as long as they are all on the same surface. Also, in the examples shown in Figures 1 and 2, the air outlet 9 and the through hole 6E are a single integrated hole, but the air outlet 9 and the through hole 6E may be separate holes.

[0020] Furthermore, protective fences (water-proof umbrellas) 10 are formed on the upper, lower, left, and right edges of the wall 4 in which each hole is formed, surrounding the wall 4 to prevent water from entering the through holes 6A to 6E, the upper air inlet 7, the lower air inlet 8, and the air outlet 9 from the outside. The height of the protective fence 10 can be set as appropriate, but for example, the fence is set to be 5 mm high from the wall 4. Here, the on-board electronic control unit 1 mounted on the vehicle may be subject to water dripping from above, for example, condensed water or drainage from the on-board air conditioner. Therefore, as shown in Figures 1 and 2, through holes 6A to 6E, the upper air inlet 7, the lower air inlet 8, and the air outlet 9 are formed in one wall 4, and further protective fences 10 are formed around the wall 4 to make it difficult for water dripping from above to enter the through holes 6A to 6E, the upper air inlet 7, the lower air inlet 8, and the air outlet 9.

[0021] Furthermore, in conventional in-vehicle electronic control devices, which have through-holes 6A to 6E, upper air inlet 7, lower air inlet 8, and air outlet 9 arranged on multiple surfaces, there was a problem that the installation position and direction on the vehicle were restricted (mounting restrictions), such as being only able to be installed in a specific orientation in order to prevent water from entering the housing 3. In contrast, in the in-vehicle electronic control device 1 of this embodiment, by consolidating each of the holes, such as through-holes 6A to 6E, upper air inlet 7, lower air inlet 8, and air outlet 9, on a single surface, it is possible to alleviate mounting restrictions compared to conventional devices.

[0022] Furthermore, when the circuit board 15 is housed inside the housing 3, the through holes 6A to 6E are formed in positions corresponding to the connectors 5A to 5F attached to the circuit board. In order to prevent water and dust from entering from the outside, it is desirable that the size of the through holes 6A to 6E be as small as possible, large enough for the connectors 5A to 5F to pass through. Therefore, the position and shape of the through holes 6A to 6E are designed to correspond to the position and shape of the connectors 5A to 5F. In the examples shown in Figures 1 and 2, the through hole for connector 5E and the through hole for connector 5F are the same through hole 6E, but they may also be separate through holes.

[0023] Furthermore, both the upper air inlet 7 and the lower air inlet 8 are air vents for allowing air to flow into the interior of the housing 3 from the outside, but as shown in Figure 1 when viewed from the side, they are formed in the shape of elongated strips, divided into upper and lower sections. To prevent dust and debris from being sucked into the interior, it is desirable that the upper air inlet 7 and the lower air inlet 8 have, for example, a fine mesh or filter attached to their surfaces. In addition, while the lower air inlet 8 has a strip shape with a uniform width, the upper air inlet 7 has a strip shape with a width that gradually widens in the length direction.

[0024] Here, Figure 4 is a magnified view of the area around the upper air inlet 7 of the wall 4. As shown in Figure 4, the upper air inlet 7 has a shape in which the width D gradually widens from right to left when viewed horizontally as shown in Figure 1. Furthermore, as will be described later, a fan 12 is located in the back right of the inside of the housing 3 (see Figure 5), meaning that the upper air inlet 7 has a band-like shape in which the width widens as it moves further away from the fan 12. As a result of the upper air inlet 7 having the band-like shape described above, when the fan 12 operates, it becomes possible to make the airflow volume of the air flowing in from the upper air inlet 7 as uniform as possible.

[0025] On the other hand, the air outlet 9 is an air vent that allows air to flow from the inside to the outside of the housing 3, and is located between the upper air inlet 7 and the lower air inlet 8, and has a rectangular shape. Since the air outlet 9 is an air outlet, there is no need to attach a mesh or filter to it, and a part of the heat dissipation fins 11, which will be described later, is exposed. However, a mesh or filter may be attached to the air outlet 9. When the fan 12 inside the housing 3 operates as described later, the air that flows in from the upper air inlet 7 and the lower air inlet 8 and the airflow generated by the fan 12 pass through the heat dissipation fins 11 and flow out of the housing 3 through the air outlet 9. This cools the electronic components (e.g., CPU, GPU, SOC, etc.) inside the housing 3.

[0026] [Internal Configuration of the On-board Electronic Control Unit] Next, the internal configuration of the on-board electronic control unit 1 according to this embodiment will be described using Figure 5. Figure 5 is an exploded perspective view of the on-board electronic control unit 1 according to this embodiment.

[0027] As shown in Figure 5, the in-vehicle electronic control unit 1 has a circuit board 15 positioned within the internal space formed by the walls of the housing 3. Various electronic components and connectors 5A to 5F are attached to the circuit board 15 by soldering, and the heat dissipation fins 11 and fan 12 are also attached by fastening means such as screws.

[0028] Connectors 5A to 5F are connectors to which power cables and communication cables for communicating with other ECUs installed in the same vehicle are connected. For example, connector 5A is the connector to which a power cable is connected for receiving power from a power source such as the vehicle's ACC power supply or onboard battery. Connectors 5B to 5F are connectors to which communication cables for communicating with other ECUs are connected.

[0029] On the other hand, electronic components arranged on the circuit board 15 include, for example, an SOC (System-on-a-chip) 16, electrolytic capacitors, coils, and other ICs. In particular, the SOC 16 is a technology-intensive semiconductor that integrates multiple semiconductor elements such as a computing element (CPU), memory elements (DRAM, flash memory), a DSP (Digital Signal Processor), and a graphics computing element (GPU) onto a single chip, and it becomes a heat generating unit that generates heat when computation is performed.

[0030] Furthermore, the on-board electronic control unit 1 has a heat dissipation fin 11 and a fan 12 as means (cooling module) for cooling the SOC 16, which is the heat generating part.

[0031] The following describes the heat dissipation fins 11 and the fan 12. The heat dissipation fins 11, also called heat sinks, are made of a metal with high thermal conductivity, such as aluminum or copper. The heat dissipation fins 11 are shaped to increase the surface area for heat dissipation. For example, as shown in Figure 6, they have a shape in which multiple plates 21 called fins are erected vertically from the surface 20 that contacts the heat generating part. The orientation of the plates 21 is parallel to the airflow generated by the operation of the fan 12, that is, the direction in which the airflow passes between the plates 21. The shape of the heat dissipation fins 11 is not limited to the example shown in Figure 6, and may be, for example, pincushion-shaped, bellows-shaped, or tunnel-shaped.

[0032] On the other hand, fan 12 is a so-called centrifugal fan, which is capable of drawing in air from the direction of the rotation axis of the blades 22 by rotating the blades 22 and expelling air perpendicular to the rotation axis. Figure 7 shows an example of fan 12. Fan 12 has an outlet 23 formed perpendicular to the rotation axis of the blades 22, and as the blades 22 rotate, the air that is emitted radially around them flows along the inside of the case and is expelled from the outlet 23. In other words, it is a structure that expels air perpendicular to the rotation axis and only in a specific direction. When fan 12 operates, it generates airflow.

[0033] In this embodiment, the heat dissipation fins 11 and fan 12 are arranged adjacent to each other on the base plate 17 as shown in Figure 5. The base plate 17 is a plate made of a metal with high thermal conductivity, such as aluminum or copper, and one side is in contact with the SOC 16, which is the heat generating part. The heat dissipation fins 11 and fan 12 are arranged on the other side. In particular, since the SOC 16 and the heat dissipation fins 11 are positioned opposite each other with the base plate 17 in between, the heat dissipation fins 11 are in contact with the SOC 16, which is the heat generating part, via the base plate 17, and the heat dissipation fins 11 can dissipate heat from the SOC 16. Furthermore, the airflow generated by the fan 12 makes it possible to improve the heat dissipation efficiency of the heat dissipation fins 11 as follows.

[0034] The orientation of the heat dissipation fins 11 and fan 12 relative to the base plate 17 is such that the outlet 23 of the fan 12 faces the heat dissipation fins 11. In particular, in this embodiment, the fan 12 and heat dissipation fins 11 are positioned such that the airflow generated by the fan 12 passes through the heat dissipation fins 11 and flows to the air outlet 9, and furthermore, the position of the fan 12 is upstream of the generated airflow relative to the heat dissipation fins 11. In addition, one end of the heat dissipation fins 11 is oriented to face the outlet 23 of the fan 12. By installing them in this orientation, when the fan 12 is operating, the air discharged from the outlet 23 can pass between the plates 21 of the heat dissipation fins 11. As shown in Figures 1 and 2, the other end of the plates 21 of the heat dissipation fins 11 is located at the air outlet 9, so the air that has passed between the plates 21 of the heat dissipation fins 11 is discharged to the outside of the housing 3 through the air outlet 9. Here, the heat dissipation efficiency of the heat dissipation fins 11 is affected not only by the surface area of ​​the heat dissipation fins 11 but also by the airflow rate of the air passing through the heat dissipation fins 11. The larger the surface area and the greater the airflow rate of the air passing through the heat dissipation fins 11, the better the heat dissipation efficiency. Therefore, it is possible to improve the heat dissipation efficiency of the heat dissipation fins 11 by generating airflow with the fan 12.

[0035] [Airflow in the On-board Electronic Control Unit] Next, the airflow when the fan 12 is operated in the on-board electronic control unit 1 having the above-described configuration will be explained using Figure 8. Figure 8 is a diagram showing the airflow generated by the fan 12 in the on-board electronic control unit 1 according to this embodiment.

[0036] As shown in Figure 8, when the fan 12 is operated, the blades 22 rotate, drawing in air from the top of the fan 12 and expelling it from the outlet 23. This generates an airflow inside the housing 3, which flows into the housing 3 through the upper air inlet 7 and the lower air inlet 8, and then passes through the fan 12 and the heat dissipation fins 11 before being discharged outside the housing through the air outlet 9. As the airflow passes through the heat dissipation fins 11, it absorbs heat from the fins 11, making it possible to cool the SOC 16, which is the heat generating part.

[0037] Furthermore, as mentioned above, the upper air inlet 7 has a band-like shape that widens as it moves further away from the fan 12 (Figure 4), so it is possible to make the airflow volume of the air flowing in from the upper air inlet 7 as uniform as possible, and thus improve the heat dissipation effect of the heat dissipation fins 11.

[0038] Furthermore, since the airflow entering through the upper air inlet 7 passes over the top surface of the circuit board 15, it can be expected that the airflow passing over the top surface of the circuit board 15 will also have the effect of cooling other electronic components placed on the circuit board 15 besides the SOC 16.

[0039] [Modification 1] The in-vehicle electronic control device 1 according to the embodiment described above can also be configured as shown in Figure 9. Figure 9 is a diagram illustrating the in-vehicle electronic control device 1 according to the first modification.

[0040] In the first modified example shown in Figure 9, the heat dissipation fins 11 are positioned at a distance from the air outlet 9. Between the heat dissipation fins 11 and the air outlet 9, there is a pair of upper and lower air inlet plates 31 and 32 that guide the airflow that has passed through the heat dissipation fins 11 to the air outlet 9. It is desirable that the air inlet plates 31 and 32 be provided not only above and below the airflow path but also to the left and right, that is, so as to surround the airflow path.

[0041] In general, if the heat dissipation fins 11 and the air outlet holes 9 are placed far apart, there is a problem in that some of the hot airflow that has passed through the heat dissipation fins 11 remains inside the housing 3 instead of flowing out through the air outlet holes 9, thus reducing the cooling effect.

[0042] However, in the first modified example shown in Figure 9, by arranging the air introduction plates 31 and 32, it becomes possible to guide the airflow that has passed through the heat dissipation fins 11 to the air outlet holes 9 without leakage, even when the heat dissipation fins 11 and the air outlet holes 9 are placed at a distance from each other. As a result, the position of the heat dissipation fins 11, i.e., the position of the SOC 16 on the circuit board 15, does not necessarily have to be adjacent to the air outlet holes 9, thus improving the design flexibility.

[0043] [Modification Example 2] Furthermore, the in-vehicle electronic control device 1 according to the present embodiment can also be configured as shown in FIG. 10. FIG. 10 is a diagram illustrating the in-vehicle electronic control device 1 according to the second modification example.

[0044] In the second modification example shown in FIG. 10, the position of the fan 35 is set on the downstream side of the airflow from the heat dissipation fins 11. Also, the fan 35 is not the centrifugal fan described above, but a normal fan that generates an airflow from one side to the other along the rotation axis of the blades, and the rotation axis is arranged horizontally between the heat dissipation fins 11 and the air outflow hole 9.

[0045] As a result, when the fan 35 is operated as shown in FIG. 10, the blades are rotationally driven, taking in air from the surface on the heat dissipation fin 11 side and discharging air from the surface on the air outflow hole 9 side. Thereby, an airflow is generated inside the housing 3, and the generated airflow flows into the housing 3 from the upper air inlet hole 7 and the lower air inlet hole 8, and further passes through the heat dissipation fins 11 and the fan 35, forming a flow that is discharged from the air outflow hole 9 to the outside of the housing. When the airflow passes through the heat dissipation fins 11, it takes away the heat of the heat dissipation fins 11, so it becomes possible to cool the SOC 16 which is the heat generation part.

[0046] [Modification Example 3] As shown in FIG. 5, since the in-vehicle electronic control device 1 according to the present embodiment needs to accommodate the circuit board 15 inside the housing 3, the housing 3 is formed by combining a plurality of divided members. For example, as shown in FIG. 11, a rectangular parallelepiped housing 3 is formed by combining a box-shaped first housing 3A with one side opened and a plate-shaped second housing 3B.

[0047] Here, the first housing 3A and the second housing 3B are fixed to each other by fixing means such as screws and adhesives, but there is a possibility that a gap 40 may occur between the first housing 3A and the second housing 3B due to factors such as distortion during shaping and aging deterioration. As a result, there is a problem that water condensed from outside the housing 3 or the drainage of the in-vehicle air conditioner enters through the gap 40 into the inside of the housing 3. Therefore, in the in-vehicle electronic control device 1 according to the third modification example, a waterproof seal 41 is arranged for the purpose of closing the gap 40 between the first housing 3A and the second housing 3B. FIG. 11 is a diagram illustrating the in-vehicle electronic control device 1 according to the third modification example.

[0048] Incidentally, the material of the seal 41 may be an organic material such as rubber or an inorganic material such as metal. Also, its shape can be appropriately selected. In the example shown in FIG. 11, the seal 41 is arranged on the outer surface of the housing 3, but the seal 41 may be arranged so as to be sandwiched between the first housing 3A and the second housing 3B.

[0049] By arranging the seal 41, it becomes possible to prevent water from entering the inside of the housing 3 from the gap 40. Also, if there is a gap 40 between the first housing 3A and the second housing 3B, when the fan 35 is driven, air may flow in from the gap 40, and the expected cooling effect may not be obtained. However, by arranging the seal 41, it is also possible to prevent air from flowing into the inside of the housing 3 from locations other than the air inlet holes 7 and 8.

[0050] 〔Fourth Modification〕On the other hand, a configuration for preventing water from entering the inside of the housing 3 without using the seal 41 is also conceivable. In the description of the above-described third modification, it was described that if there is a gap 40 between the first housing 3A and the second housing 3B, when the fan 35 is driven, air may flow in from the gap 40, and the expected cooling effect may not be obtained. However, in reality, the gap 40 is extremely small in area compared to the air inlet holes 7 and 8, so the inflow of air from the gap 40 is negligibly small.

[0051] Therefore, even if the seal 41 is not arranged, the problem of a decrease in cooling efficiency can be solved. However, if the seal 41 is not used, there remains a problem that condensed water or the drainage of the in-vehicle air conditioner enters the inside of the housing 3 from the gap 40 between the first housing 3A and the second housing 3B. Therefore, in the fourth modification, when combining the box-shaped first housing 3A and the plate-shaped second housing 3B as shown in FIG. 12, the second housing 3B is combined so as to be located inside by a distance L from the opening surface of the first housing 3A. FIGS. 12 to 14 are diagrams for explaining the in-vehicle electronic control device 1 according to the fourth modification.

[0052] The distance L can be set as appropriate, but for example, it can be set to 5 mm to 10 mm. Also, as shown in Figure 12, a stepped portion 42 is formed on the inner surface of the first housing 3A, and the second housing 3B is combined with the first housing 3A so that the edge of the first housing 3A abuts against the stepped portion 42. Then, they are fixed to each other by fastening means such as screws or adhesive.

[0053] As a result, the gap 40 between the first housing 3A and the second housing 3B is hidden at the back without being exposed. Unless the in-vehicle electronic control unit 1 is positioned so that the second housing 3B is on top, even if condensed water or drainage from the in-vehicle air conditioner drips down from above, it is possible to prevent the condensed water or drainage from the in-vehicle air conditioner from entering the interior of the housing 3 through the gap 40 between the first housing 3A and the second housing 3B.

[0054] Furthermore, in the in-vehicle electronic control device 1 according to the fourth modification, as shown in Figure 13, the wall surface of the first housing 3A is inclined by a predetermined angle θ from a direction perpendicular to the opening and the second housing 3B. Specifically, the four wall surfaces that form the stepped portion 42 on the inner surface, in other words, the four wall surfaces surrounding the opening, are made into a trapezoidal shape that gradually widens toward the opening. Note that the inclination angle θ of each of the four wall surfaces may all be the same angle, or they may be different angles. Also, instead of making all four wall surfaces surrounding the opening into a trapezoidal shape, only two opposing wall surfaces may be made into a trapezoidal shape.

[0055] As a result, when the on-board electronic control unit 1 is installed on the vehicle in the orientation shown in Figure 13, even if condensed water or drainage from the on-board air conditioner drips down from above, it will flow along the slope of the wall in the opposite direction from the opening. As a result, it is possible to more reliably prevent condensed water or drainage from the on-board air conditioner from entering the inside of the housing 3 through the gap 40 between the first housing 3A and the second housing 3B.

[0056] As described in detail above, the in-vehicle electronic control device 1 according to this embodiment includes a fan 12 that generates airflow when it operates, a circuit board 15 on which electronic components and connectors 5A to 5F are mounted, and a housing 3 that is mounted on a vehicle and has multiple walls that form an internal space housing the fan 12 and the circuit board 15. The housing 3 has through holes 6A to 6E through which the connectors 5A to 5F pass, air inlet holes 7 and 8 for bringing air into the housing 3 from the outside, and air outlet holes 9 for releasing air from the inside of the housing 3 to the outside. This makes it possible to alleviate restrictions on mounting the housing in terms of water entering the housing. As a result, when mounting the housing 3 on a vehicle, it is possible to prevent condensed water and drainage from the in-vehicle air conditioner from entering the housing through the air inlet holes 7 and 8, air outlet holes 9, through holes 6A to 6E, etc. At the same time, even when it is necessary to arrange a large number of in-vehicle electronic control devices inside the vehicle, each housing 3 can be positioned in a relatively free position and orientation, improving the freedom of the vehicle's interior design. Furthermore, the upper air inlet 7 has a band-like shape that widens as it moves further away from the fan 12, which allows for a uniform airflow rate from the upper air inlet 7 and improves cooling efficiency. Additionally, the fan 12 and the heat dissipation fins 11 are positioned around the SOC 16, which is a heat generating section containing at least some electronic components, to dissipate heat from the SOC 16. The fan 12 and the heat dissipation fins 11 are positioned such that the airflow generated by the fan 12 passes through the heat dissipation fins 11 and flows to the air outlet 9. Therefore, generating airflow with the fan 12 improves the heat dissipation efficiency of the heat dissipation fins 11. Furthermore, in the first modified example described above, the heat dissipation fins 11 are positioned at a distance from the air outlet holes 9, and air introduction plates 31 and 32 are provided between the heat dissipation fins 11 and the air outlet holes 9 to guide the airflow that has passed through the heat dissipation fins 11 to the air outlet holes 9. Therefore, even when the heat dissipation fins 11 and the air outlet holes 9 are positioned at a distance from each other, it is possible to guide the airflow that has passed through the heat dissipation fins 11 to the air outlet holes 9 without any leakage. As a result, the position of the heat dissipation fins 11, i.e., the position of the SOC 16 on the circuit board 15, does not necessarily have to be adjacent to the air outlet holes 9, and the degree of design freedom is improved.

[0057] It should be noted that the present invention is not limited to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of the invention. For example, in this embodiment, there are two air inlet holes, an upper air inlet hole 7 and a lower air inlet hole 8, but only one of them may be provided as an air inlet hole. Also, in the example shown in Figure 1, an air outlet hole 9 is provided between the upper air inlet hole 7 and the lower air inlet hole 8, but the positional relationship between the upper air inlet hole 7, the lower air inlet hole 8 and the air outlet hole 9 is not limited to the positional relationship shown in Figure 1, and can be changed as appropriate as long as they are on the same wall. Furthermore, by concentrating the through holes 6A to 6E, the upper air inlet hole 7, the lower air inlet hole 8, and the air outlet hole 9 on one surface, the effect of relaxing mounting restrictions can be expected, so the protective fence 10 is not necessarily required and may be omitted.

[0058] Furthermore, in this embodiment, the upper air inlet 7 has a band-like shape that widens as it moves further away from the fan 12, while the lower air inlet 8 has a band-like shape with a uniform width. However, the lower air inlet 8 may also have a band-like shape with a changing width, similar to the upper air inlet 7. On the other hand, the upper air inlet 7 may also have a band-like shape with a uniform width.

[0059] [Note] The embodiments described above also disclose the following inventions. In the following description, the names and expressions of corresponding components in the embodiments, and the reference numerals used in the drawings, are noted in parentheses for reference. However, the components of each invention are not limited to these notes.

[0060] (Invention A) The on-board electronic control device (1) according to claim 1, wherein the housing (3) is formed by combining a plurality of members (3A, 3B), and a seal (41) is disposed between the plurality of members.

[0061] According to this, it becomes possible to prevent condensed water and drainage from the vehicle's air conditioner from entering the enclosure through gaps between the multiple components that make up the enclosure.

[0062] (Invention B) The on-board electronic control device (1) according to claim 1, wherein the housing (3) is formed by combining a box-shaped first housing (3A) with one end open and a plate-shaped second housing (3B), and when the first housing and the second housing are combined, the second housing is positioned inward by a predetermined distance from the opening surface of the first housing.

[0063] According to this, it becomes possible to prevent condensed water and drainage from the vehicle's air conditioner from entering the enclosure through gaps between the multiple components that make up the enclosure.

[0064] (Invention C) The in-vehicle electronic control device (1) according to Invention B, wherein the wall surface forming the opening of the first housing (3A) is a trapezoidal shape that gradually widens in the direction of the opening.

[0065] According to this design, even if condensed water or drainage from the vehicle's air conditioner drips down from above, it will flow along the slope of the wall in the opposite direction from the opening. This makes it possible to more reliably prevent condensed water or drainage from the vehicle's air conditioner from entering the enclosure through gaps between the multiple components that make up the enclosure.

[0066] 1...Automotive electronic control unit, 3...Housing, 4...Wall, 5A-5F...Connector, 6A-6E...Through-hole, 7...Upper air inlet, 8...Lower air inlet, 9...Air outlet, 11...Heat dissipation fin, 12...Fan, 15...Circuit board, 16...SOC (Electronic component, heat generating section), 31, 32...Air introduction plate

Claims

1. An in-vehicle electronic control device comprising: a fan that generates airflow when it operates; a circuit board on which electronic components and connectors are mounted; and a housing that is mounted on a vehicle and has a plurality of walls forming an internal space that houses the fan and the circuit board, wherein one of the plurality of walls of the housing has a through hole through which the connector passes, an air inlet for bringing air into the housing from the outside, and an air outlet for releasing air from the inside of the housing to the outside.

2. The in-vehicle electronic control device according to claim 1, wherein the air inlet has a band-like shape that widens as it moves further away from the fan.

3. The in-vehicle electronic control device according to claim 1 or 2, wherein the fan and the heat dissipation fins are arranged around a heat generating section which includes at least a portion of the electronic components, and the heat dissipation fins are arranged in such a positional relationship that the airflow generated by the fan passes through the heat dissipation fins and flows to the air outlet hole.

4. The in-vehicle electronic control device according to claim 3, wherein the heat dissipation fins are arranged at a distance from the air outlet holes, and an air introduction plate is provided between the heat dissipation fins and the air outlet holes for guiding the airflow that has passed through the heat dissipation fins to the air outlet holes.

Images