WO2022269978A1

WO2022269978A1 - Vehicle-mounted electronic control device

Info

Publication number: WO2022269978A1
Application number: PCT/JP2022/004024
Authority: WO
Inventors: 恵子上之; 義夫河合; 諒秋葉
Original assignee: 日立Astemo株式会社
Priority date: 2021-06-24
Filing date: 2022-02-02
Publication date: 2022-12-29
Also published as: JPWO2022269978A1

Abstract

This vehicle-mounted electronic control device comprises: a circuit board on which electronic components are mounted; an inner case for accommodating the circuit board; and an outer case for accommodating the inner case.

Description

Automotive electronic control unit

The present invention relates to an in-vehicle electronic control device.

In general, vehicles such as automobiles are equipped with multiple electronic control units (ECUs) to control various objects, including the engine, power steering, brakes, and airbags. An electronic control device mounted on a vehicle (hereinafter also referred to as an "on-vehicle electronic control device") has a structure in which a circuit board on which electronic components are mounted is housed inside a housing (for example, Patent Document 1 ).

JP 2016-141173 A

In general, in-vehicle electronic control units are often installed in the engine room. On the other hand, in recent years, vehicles are equipped with more electronic control units for safe driving and automatic driving. In some cases, the in-vehicle electronic control unit is installed in the vehicle interior as well as in the engine room.

However, when installing an in-vehicle electronic control unit inside the vehicle, there is a risk that the driver may accidentally hit the in-vehicle electronic control unit with his or her limbs. If the housing of the in-vehicle electronic control unit is damaged by such an external impact, there is a risk of hindering the safety of driving support and automatic driving.

The purpose of the present invention is to provide an in-vehicle electronic control unit that can contribute to safer driving support and automatic driving.

In order to solve the above problems, for example, the configurations described in the claims are adopted.
The present application includes a plurality of means for solving the above problems. and a second housing that accommodates a body.

Advantageous Effects of Invention According to the present invention, it is possible to contribute to safer driving assistance and automatic driving.
Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a perspective view of an in-vehicle electronic control device according to a first embodiment viewed from an oblique direction; FIG. FIG. 2 is a cross-sectional view of the in-vehicle electronic control device shown in FIG. 1 taken along the line AA; 2 is a cross-sectional view of the in-vehicle electronic control device shown in FIG. 1 taken along the line BB. FIG. It is a figure which shows the example which formed the ventilation hole circularly. FIG. 11 is a perspective view of an in-vehicle electronic control unit according to a comparative embodiment as viewed from an oblique direction; It is a figure explaining the flow of the air implement|achieved by the vehicle-mounted electronic control apparatus which concerns on 1st Embodiment. It is a figure which shows the example which formed the ventilation hole in the square. It is a figure which shows the example which formed the ventilation hole in the triangle. It is a figure which shows the example which formed the ventilation hole in the shape of a pentagon. It is a figure explaining the 1st modification of the vehicle-mounted electronic control apparatus which concerns on 1st Embodiment. It is a figure explaining the 2nd modification of the vehicle-mounted electronic control apparatus which concerns on 1st Embodiment. It is the perspective view which looked at the vehicle-mounted electronic control apparatus which concerns on 2nd Embodiment from the diagonal direction. 13 is a cross-sectional view of the in-vehicle electronic control device shown in FIG. 12 taken along the line CC. FIG. FIG. 13 is a cross-sectional view of the in-vehicle electronic control device shown in FIG. 12 taken along line DD; It is a figure explaining the 1st modification of the vehicle-mounted electronic control apparatus which concerns on 2nd Embodiment. It is a figure explaining the 2nd modification of the vehicle-mounted electronic control apparatus which concerns on 2nd Embodiment. It is the perspective view which looked at the vehicle-mounted electronic control apparatus which concerns on 3rd Embodiment from the diagonal direction. It is a figure explaining the modification of the vehicle-mounted electronic control apparatus which concerns on 3rd Embodiment. It is a cross-sectional view showing an in-vehicle electronic control device according to a fourth embodiment. It is the perspective view which looked at the vehicle-mounted electronic control apparatus which concerns on 5th Embodiment from the diagonal direction. FIG. 11 is a perspective view of an in-vehicle electronic control device according to a sixth embodiment, as seen from an oblique direction;

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, elements having substantially the same function or configuration are denoted by the same reference numerals, and overlapping descriptions are omitted.

<First Embodiment>
FIG. 1 is a perspective view of an in-vehicle electronic control device according to a first embodiment, viewed from an oblique direction. 2 is a cross-sectional view of the in-vehicle electronic control device shown in FIG. 1 taken along the line AA, and FIG. 3 is a cross-sectional view of the in-vehicle electronic control device shown in FIG. 1 taken along the line BB. In-vehicle electronic control devices are not limited to electronic control devices mounted on vehicles that run on liquid fuel such as gasoline or light oil, but also include vehicles that run on hydrogen as fuel, hybrid vehicles, and electric vehicles. It can also be widely applied to electronic control units mounted on vehicles such as. Moreover, the object controlled by the in-vehicle electronic control unit is not limited to a specific object.

In the following description, in order to clarify the shape and positional relationship of each part of the vehicle electronic control unit, the thickness direction (height direction) of the vehicle electronic control unit is assumed to be the Z direction, and two directions orthogonal to the Z direction are described. Of the axial directions, one direction is defined as the X direction, and the other direction is defined as the Y direction. The X-direction, Y-direction and Z-direction are directions perpendicular to each other.

As shown in FIGS. 1 to 3, the vehicle electronic control device 100 according to the first embodiment includes a circuit board 10, an inner case 11 that houses the circuit board 10, and an outer case 12 that houses the inner case 11. , is equipped with

(circuit board 10)
The circuit board 10 is configured by a printed wiring board, which is a rigid board using glass epoxy resin as a base material, for example. The circuit board 10 may have wiring patterns formed on only one side, or may have wiring patterns formed on both sides. The circuit board 10 is a board forming a rectangle (rectangular or square) when viewed from the Z direction. A heat-generating component 15 and a connector component 16 are mounted on the circuit board 10 as examples of electronic components. In addition to the heat-generating component 15 and the connector component 16, the circuit board 10 is mounted with electronic components (not shown) such as a switching element, a resistance element, a capacitor, and a diode. The heat-generating component 15 and the connector component 16 are mounted on the circuit board 10 using one board surface 10A of the circuit board 10 as a common mounting surface. That is, the heat-generating component 15 and the connector component 16 are mounted on the same surface of the circuit board 10 . Also, the heat-generating component 15 and the connector component 16 are electrically connected via a wiring pattern (not shown) formed on the board surface 10A of the circuit board 10 .

The heat-generating component 15 is an electronic component containing an arithmetic circuit such as a CPU (Central Processing Unit) or GPU (Graphics Processing Unit) called a microcomputer. The heat-generating component 15 is a highly functional component having a processor such as an IC (integrated circuit) chip or a semiconductor chip and operating at a processing speed of several hundred MHz to several GHz. Such high-performance parts generate a lot of heat in order to perform high-speed arithmetic processing. That is, the heat-generating component 15 is an electronic component that generates heat. Electronic components (for example, diodes) are mounted on the circuit board 10 in addition to the heat-generating components 15, and the amount of heat generated is mostly electronic components having arithmetic functions. Therefore, in this specification, an electronic component having a computing function is defined as a heat-generating component. The heat-generating component 15 is not limited to what is called a microcomputer, and may be, for example, a memory that communicates with a microcomputer. The heat-generating component 15, which is a highly functional component, consumes extremely high power, and may reach several tens of watts.

The heat-generating component 15 is a surface-mounted electronic component. The heat-generating component 15 is arranged on one side (left side in FIG. 3) of the circuit board 10 in the Y direction. In this embodiment, as an example, two heat-generating components 15 are mounted on one circuit board 10 . The two heat generating components 15 are arranged with a predetermined spacing in the X direction. The number of heat generating components 15 mounted on the circuit board 10 may be one or three or more.

The connector component 16 is arranged on the other side of the circuit board 10 in the Y direction (right side in FIG. 3). Specifically, the connector component 16 is mounted on the end of the circuit board 10 opposite to the side on which the heat generating component 15 is mounted in the Y direction. The connector component 16 is a connector component for transmitting an electrical signal generated by the circuit board 10 to an external device and for receiving an electrical signal generated by an external device at the circuit board 10 . Examples of the external devices that exchange electrical signals with the vehicle electronic control unit 100 include vehicle electronic control units other than the vehicle electronic control unit 100, cameras, sensors, actuators, and the like. A harness (not shown) is connected to the connector part 16 . A harness is a wiring bundle for electrically connecting the circuit board 10 and an external device. A harness has a structure in which a metal wire, which is a conductor for making electrical connections, is covered with a protective film, which is an insulator. The harness is pulled out of the outer case 12 through a drawer (not shown) provided in the outer case 12 . Therefore, the connector component 16 has a function of releasing heat to the outside of the outer case 12 through the harness. In this embodiment, two connector components 16 are mounted on one circuit board 10 as an example. The two connector parts 16 are arranged with a predetermined spacing in the X direction. The number of connector components 16 mounted on the circuit board 10 may be one or three or more.

(Inner case 11)
The inner case 11 is a hollow case having inside a first space 21 capable of accommodating the circuit board 10 . The inner case 11 corresponds to the first housing. The inner case 11 is a polyhedron, more specifically a hexahedron (rectangular parallelepiped). The inner case 11 is preferably a metal case. The metal forming the inner case 11 is preferably aluminum or an alloy containing aluminum as the main material. However, the material forming the inner case 11 is not limited to metal, and may be resin. Also, the inner case 11 may be partially made of metal and the other portion made of resin.

The inner case 11 is mainly composed of an inner case main body 22 and an inner case lid 23 . The inner case main body 22 is a structure having a U-shaped cross section with one opening in the Z direction (upper side in FIGS. 2 and 3). The inner case lid 23 is a plate-like structure having outer dimensions larger than the opening dimensions of the inner case main body 22 . The first space 21 described above is a substantially closed space by covering the opening of the inner case main body 22 with the inner case lid 23 . The inner case main body 22 and the inner case lid 23 are coupled by screws (not shown), for example. A stepped portion 24 is formed inside the inner case main body 22 . The circuit board 10 is mounted on the inner case main body 22 with, for example, screws (not shown) while the circuit board 10 is placed on the stepped portion 24 . The circuit board 10 is arranged so that one board surface 10A faces the inner case lid 23 .

The inner case 11 is supported within the first space 21 of the inner case 11 by a plurality of brackets 30 . In this embodiment, as an example, the inner case 11 is supported by four brackets 30 . The four brackets 30 are arranged so as to sandwich the inner case 11 in the X direction. Each bracket 30 is formed in an L shape. The bracket 30 integrally has a first attachment piece 31 and a second attachment piece 32, as shown in FIG. The first attachment piece 31 is attached to the inner bottom surface of the outer case 12 in a fixed state. The second attachment piece 32 is fixedly attached to the side surface of the inner case main body 22 . A gap is formed between the outer surface of the inner case 11 and the inner surface of the outer case 12 when the inner case 11 is attached to the outer case 12 using the plurality of brackets 30 as described above. This gap is formed over the entire circumference of the inner case 11, which is a polyhedron.

(Outer case 12)
The outer case 12 is a hollow case having inside a second space 25 capable of accommodating the inner case 11 . The outer case 12 corresponds to a second housing. The outer case 12 is a polyhedron, more specifically a hexahedron (rectangular parallelepiped). The outer case 12 is arranged so as to surround the entire surface of the inner case 11 which is a polyhedron. As a result, the inner case 11 is mechanically protected by the outer case 12 . Outer case 12 is preferably a metal case. The metal forming the outer case 12 is preferably aluminum or an alloy containing aluminum as the main material. However, the material forming the outer case 12 is not limited to metal, and may be resin. A part of the outer case 12 may be made of metal and the other part may be made of resin.

The outer case 12 is mainly composed of an outer case main body 26 and an outer case lid 27. The outer case main body 26 is a structure having a U-shaped cross section with one side in the Z direction (upper side in FIGS. 2 and 3) open. The outer case lid 27 is a plate-like structure having outer dimensions larger than the opening dimension of the outer case main body 26 . The above-described second space 25 is a substantially closed space by closing the opening of the outer case main body 26 with the outer case lid 27 . The outer case main body 26 and the outer case lid 27 are connected by screws (not shown), for example.

Here, in the present embodiment, as an example, it is assumed that the in-vehicle electronic control device 100 is mounted in a vehicle in the orientation (orientation) shown in FIGS. Define as follows. First, let the surface arranged facing one side of the Z direction be the upper surface 12A, and let the surface arranged facing the other side of the Z direction be the lower surface 12B. Also, the four surfaces arranged in the X direction and the Y direction are

side surfaces

12C, 12D, 12E, and 12F, respectively. The area of the upper surface 12A is larger than the areas of the individual side surfaces 12C, 12D, 12E, 12F and the same as the area of the lower surface 12B. The in-vehicle electronic control unit 100 can also be mounted on a vehicle with the two opposing side surfaces of the outer case 12 oriented in the vertical direction. Further, the in-vehicle electronic control unit 100 can be mounted in the vehicle in an oblique posture with respect to the horizontal plane.

The outer case 12 is provided with communicating

portions

35 and 36 . The communicating portion 35 is a portion that communicates the outside and the inside of the outer case 12 , and the communicating portion 36 is also a portion that communicates the outside and the inside of the outer case 12 . Communication means being spatially connected. That is, the communicating

portions

35 and 36 are portions that connect the space outside the outer case 12 and the space inside the outer case 12 (the second space 25). The communicating

portions

35 and 36 are preferably provided in at least two locations of the outer case 12 so that air is exchanged between the space outside the outer case 12 and the space inside the outer case 12 . In addition, the two locations where the communicating

portions

35 and 36 are provided are located apart from each other so that air can be exchanged smoothly between the space outside the outer case 12 and the space inside the outer case 12. preferably.

In the present embodiment, as an example, communicating

portions

35 and 36 are provided at two locations on the outer case 12 . Specifically, the communicating portion 35 is provided on the side surface 12E of the outer case 12 so that the two locations where the communicating

portions

35 and 36 are provided are located apart from each other. Located on 12F. The side surfaces 12E and 12F are positioned apart from each other so that one side serves as an air inflow side and the other side serves as an air outflow side. Moreover, the side surface 12E and the side surface 12F are arranged to face each other in the Y direction.

As can be seen from FIGS. 1 and 3, the communicating portion 35 provided on the side surface 12E is provided at a position closer to the heat-generating component 15 than the connector component 16 is. On the other hand, the communicating portion 36 provided on the side surface 12</b>F is provided at a position closer to the connector component 16 than the heat generating component 15 . The communicating portion 35 is composed of a plurality of vent holes 35a, and the communicating portion 36 is composed of a plurality of vent holes 36A. The plurality of ventilation holes 35A are densely arranged in a matrix arrangement, and the plurality of ventilation holes 36A are also densely arranged in a matrix arrangement. The individual air holes 35A and 36B are circularly formed by, for example, laser processing, press processing, or the like (see FIG. 4). Also, the plurality of ventilation holes 35A are formed substantially throughout the side surface 12E in the X direction, and the plurality of ventilation holes 36A are formed substantially throughout the side surface 12F in the X direction. In the Z direction, the communication portion 35 and the communication portion 36 are arranged at the same position, and are arranged closer to the upper surface 12A side than the lower surface 12B side of the outer case 12 . As a result, the communicating portion 35 and the communicating portion 36 are arranged close to the heat-generating component 15 serving as the main heat source on the circuit board 10 . For the communicating

portions

35 and 36, for example, openings (not shown) are formed in the side surfaces 12E and 12F of the outer case 12, respectively, and a mesh member (not shown) such as a wire mesh is used to block the openings. Alternatively, it can be formed by fixing a punching plate (not shown) or the like to the outer case 12 by welding or the like.

In the vehicle-mounted electronic control device 100 according to the first embodiment described above, the circuit board 10 is accommodated in the inner case 11 and then the inner case 11 is accommodated in the outer case 12 . In other words, the in-vehicle electronic control unit 100 has a structure in which the circuit board 10 is doubly surrounded by the inner case 11 and the outer case 12, that is, has a double housing structure. Therefore, the circuit board 10 and the inner case 11 can be mechanically protected by the outer case 12 . Therefore, for example, when the in-vehicle electronic control unit 100 is installed in the vehicle interior, even if a driver or a fellow passenger accidentally hits the in-vehicle electronic control unit 100 with their hands or feet, the impact is directly applied to the inner case 11. never join. Therefore, damage to the inner case 11 due to impact from the outside can be effectively avoided. In addition, since the circuit board 10 on which the heat-generating components 15 and the connector components 16 are mounted is protected by the inner case 11 within the second space 25 of the outer case 12, the in-vehicle structure realized by the electronic components such as the heat-generating components 15 is protected. There is no risk of impairing the control function of the electronic control unit 100 for the vehicle. Therefore, it is possible to provide the in-vehicle electronic control unit 100 that can contribute to safer driving assistance and automatic driving.

In addition to the above-described mechanical protection function, the above-described double housing structure has a function of protecting the inner case 11 from dust and the like, and a function of facilitating attachment of the in-vehicle electronic control unit 100 to the vehicle. also have

In addition, the double housing structure is preferably applied to an in-vehicle electronic control device mounted in the vehicle interior such as the foot of the driver's seat, the foot of the passenger seat, the back of the dashboard, the trunk room, etc. However, it is not limited to this. , and may be applied to an in-vehicle electronic control device mounted in an engine room. In other words, the vehicle-mounted electronic control device having the double housing structure can be applied to a vehicle-mounted electronic control device mounted either inside or outside the vehicle.

Furthermore, in the vehicle electronic control unit 100 according to the first embodiment described above, a configuration in which the outer case 12 is provided with the communicating

portions

35 and 36 is adopted. Therefore, it is possible to suppress deterioration in heat dissipation performance when the inner case 11 is accommodated in the outer case 12 . A detailed description will be given below.

FIG. 5 is a perspective view of an in-vehicle electronic control device according to a comparative embodiment as seen from an oblique direction.
As shown in FIG. 5, in the vehicle electronic control device 200 according to the comparative embodiment, the circuit board 10 mounted with the heat generating component 15 and the connector component 16 is housed in the inner case 11, and the inner case 11 is mounted on the outer case 12. are accommodated. Therefore, the effects of mechanically protecting the inner case 11 by the outer case 12, protecting it from dust and the like, and facilitating the attachment of the in-vehicle electronic control unit 200 can be obtained in the same manner as in the first embodiment. be done. Therefore, the in-vehicle electronic control unit 200 according to the comparative embodiment can be one embodiment.

However, in the in-vehicle electronic control device 200 according to the comparative embodiment, the outer case 12 is not provided with the communicating portion. Therefore, even if an air flow is generated outside the outer case 12 as indicated by the solid line arrow, the air flows from the outside of the outer case 12 into the inside, or the air flows out from the inside of the outer case 12 to the outside. There is no such thing as Therefore, the inside of the outer case 12 is in a situation in which air convection is difficult to occur.

On the other hand, in the in-vehicle electronic control device 100 according to the first embodiment, the outer case 12 is provided with the communicating

portions

35 and 36 . Therefore, air flows into the outer case 12 from the outside, and air flows out of the outer case 12 from the inside. Therefore, the inside of the outer case 12 is in a state where air convection is likely to occur.

Here, in the first embodiment, the communication portion 35 is provided on the side surface 12E of the outer case 12, and the communication portion 36 is provided on the side surface 12F opposite to the side surface 12E. Further, the communicating portion 35 is provided at a position close to the heat-generating component 15 , and the communicating portion 36 is provided at a position close to the connector component 16 . Therefore, the side surface 12E provided with the communicating portion 35 serves as an air inflow side, and the side surface 12F provided with the communicating portion 36 serves as an air outflow side. The reason is as follows.

On the circuit board 10, as shown in FIG. 3, the heat-generating component 15 is arranged on one side in the Y direction (left side in FIG. 3), and the connector component 16 is arranged on the other side in the Y direction (right side in FIG. 3). are placed. Further, the heat-generating component 15 generates a lot of heat, while the connector component 16 radiates heat to the outside through a harness (not shown). Therefore, the side on which the heat-generating component 15 is arranged has a relatively high temperature, and the side on which the connector component 16 is arranged has a relatively low temperature. For this reason, as indicated by the dashed arrow in FIG. 6, inside the outer case 12, air flows from the side where the heat-generating component 15 is arranged toward the side where the connector component 16 is arranged, that is, convection. occurs. At this time, the air outside the outer case 12 flows into the outer case 12 through the communicating portion 35 . Also, the air inside the outer case 12 flows out of the outer case 12 through the communicating portion 36 . Therefore, the side surface 12E provided with the communicating portion 35 is the air inflow side, and the side surface 12F provided with the communicating portion 36 is the air outflow side.

In this way, one of the two

side surfaces

12E and 12F facing each other has one side surface 12E serving as an air inflow side and the other side surface 12F serving as an air outflow side. can promote For this reason, even when the in-vehicle electronic control unit 100 is arranged in a vehicle interior, for example, the heat generated by the heat-generating component 15 as a main heat source is transferred from the outer surface of the inner case 11 to the outside of the outer case 12 along with the air flow. and can escape. Therefore, it is possible to suppress the temperature rise of the electronic components mounted on the circuit board 10, particularly the heat-generating component 15. FIG. Suppressing the temperature rise of the heat-generating component 15 contributes to maintaining the functions of the CPU and the like built in the heat-generating component 15 normally, and thus to enhancing the safety of driving assistance and automatic driving.

Also, the communicating portion 35 is located on the heat generating component 15 side, and the communicating portion 36 is located on the connector component 16 side. Therefore, the flow of air generated inside the outer case 12 can be further accelerated. This principle will be described below.

First, the connector component 16 radiates heat to the outside of the outer case 12 via a harness that electrically connects with the outside. For this reason, the connector component 16 is the component with the lowest temperature among the electronic components mounted on the circuit board 10 , and is also the lowest temperature part inside the outer case 12 . On the other hand, the heat-generating component 15 , which is a highly functional electronic component with high power consumption, is often mounted at a position far from the connector component 16 . Here, according to the basic principle of heat conduction, heat in a solid moves from the hot side to the cold side. Therefore, in the inner case 11 , heat moves from the heat-generating component 15 toward the connector component 16 . Also, the heat flux, which is the amount of heat that passes through a unit area per unit time, increases as the temperature difference in the solid increases. Therefore, the heat flux increases as the temperature difference between the heat-generating component 15 and the connector component 16 increases. On the other hand, air flows from the high pressure side to the low pressure side, that is, from the high temperature side to the low temperature side. Also, the speed at which the air flows increases as the pressure difference and the temperature difference increase. Therefore, by providing the communicating portion 35 on the heat generating component 15 side and the communicating portion 36 on the connector component 16 side, the flow of air generated inside the outer case 12 can be further accelerated. As a result, the heat transfer amount increases, so that the heat dissipation performance of the in-vehicle electronic control unit 100 can be enhanced. As a result, it is possible to achieve both mechanical protection of the inner case 11 and ensuring the heat radiation performance of the in-vehicle electronic control device 100 .

Further, inside the outer case 12 , due to the temperature difference between the heat-generating component 15 and the connector component 16 , air flows linearly from the communicating portion 35 toward the communicating portion 36 . Therefore, it is possible to prevent the speed of the air flowing inside the outer case 12 from decreasing, and allow the air to pass through the inside of the outer case 12 efficiently.

Also, part of the air flowing out from the communicating portion 36 goes around the outside of the outer case 12 to reach the communicating portion 35 and flows into the outer case 12 from this communicating portion 35 . Therefore, an air circulation path is formed between the inside and outside of the outer case 12 by the communicating

portions

35 and 36 . Therefore, heat exchange between the air existing inside and outside the outer case 12 can be promoted.

In the first embodiment, the shape of the vent holes 35A and 36A is circular (perfect circle), but the shape of the vent hole that constitutes the communicating portion may be polygonal. For example, the shape of the vent hole 35A may be quadrangular as shown in FIG. 7, triangular as shown in FIG. 8, or pentagonal as shown in FIG. Also, although not shown, the shape of the vent hole 35A may be an ellipse, a star, a cross, a slit, or the like. Such a hole shape can also be applied to the vent hole 36A. Also, the vent hole 35A and the vent hole 36A may have different shapes.

When the shape of the vent hole 35A is a shape having at least one corner such as a polygon, a star, a cross, etc., the flow of air passing through the vent hole 35A is caused in the vicinity of the vent hole 35A. prone to turbulence. When the air flow becomes turbulent in the vicinity of the ventilation holes 35A, the speed of the air flowing inside the outer case 12 increases. Therefore, heat can be efficiently released from the outer surface of the inner case 11 . Therefore, it is possible to improve the heat dissipation performance of the in-vehicle electronic control unit 100 .

In addition, in the first embodiment, of the six surfaces of the outer case 12, the communication portion 35 is provided on the side surface 12E and the communication portion 36 is provided on the side surface 12F. Thus, the communication portion 37 may be provided on the side surface 12C of the outer case 12, and the communication portion 38 may be provided on the side surface 12D opposite to the side surface 12C.

Further, as shown in FIG. 11, the side surface 12E of the outer case 12 may be provided with the communicating portion 35-1 at one location and the communicating portion 35-2 at another location. The communicating portion 35-1 is provided on one end side of the side surface 12E in the X direction, and the communicating portion 35-2 is provided on the other end side of the side surface 12E in the X direction. Further, the communicating portion 35-1 is arranged near one heat generating component 15, and the communicating portion 35-2 is arranged near the other heat generating component 15. As shown in FIG. Even when the communication portions 35-1 and 35-2 are provided only in the vicinity of the heat-generating component 15 on the side surface 12E of the outer case 12 in this way, the same heat dissipation effect as when the communication portion 35 is provided on the entire side surface 12E can be obtained. It is possible to obtain Further, when the communication portions 35-1 and 35-2 are provided only in the vicinity of the heat-generating component 15, the effect of protecting the inner case 11 from dust and the like is greater than when the communication portion 35 is provided on the entire side surface 12E. can increase Although not shown, the side surface 12F of the outer case 12 may also be provided with two communication portions (not shown), or the communication portion may be provided on the entire side surface 12F.

<Second embodiment>
FIG. 12 is a perspective view of the in-vehicle electronic control device according to the second embodiment as seen from an oblique direction. 13 is a CC sectional view of the in-vehicle electronic control device shown in FIG. 12, and FIG. 14 is a DD sectional view of the in-vehicle electronic control device shown in FIG.

As shown in FIGS. 12 to 14, the vehicle electronic control device 100B according to the second embodiment is compared with the vehicle electronic control device 100 (see FIGS. 1 to 3) according to the first embodiment described above. , in that a straightening member 41 is provided. The straightening member 41 is a member that straightens the direction of the air flowing between the inner case 11 and the outer case 12 (gap portion). The straightening member 41 is composed of a plurality of plate-like portions arranged parallel to the Y direction. As shown in FIG. 13, the plurality of plate-like portions forming the rectifying member 41 are arranged in the X direction at predetermined intervals.

The straightening member 41 is arranged at a position facing the outer case lid 27 in the Z direction. The material forming the rectifying member 41 may be resin or metal. When the rectifying member 41 is made of metal, the rectifying member 41 can function as a heat radiation fin. The rectifying member 41 as a radiation fin is preferably made of aluminum or an aluminum alloy, which is a metal with high thermal conductivity and excellent corrosion resistance. Further, the rectifying member 41 is preferably integrated with the inner case 11 in order to reduce the number of components of the in-vehicle electronic control device 100 . In this embodiment, the inner case lid 23 and the rectifying member 41 are integrally constructed. In this case, the inner case lid 23 and the rectifying member 41 are made of the same metal material, and these integral structures function as heat sinks.

The rectifying member 41 extends linearly from the side where the heat generating component 15 is arranged toward the side where the connector component 16 is arranged. Further, the side surface 12E provided with the communicating portion 35 and the side surface 12F provided with the communicating portion 36 are arranged to face each other in the Y direction, which is the extending direction of the straightening member 41 .

On the other hand, inside the inner case 11, a heat transfer member 45 is provided. The heat transfer member 45 is a member that transfers heat generated by the heat generating component 15 to the inner case 11 . The heat transfer member 45 is made of, for example, thermally conductive resin, and more specifically TIM (Thermal Interface Material). The heat transfer member 45 is sandwiched between the heat generating component 15 and the inner case lid 23 . Also, the heat transfer member 45 is in close contact with both the heat generating component 15 and the inner case lid 23 . By arranging the heat transfer member 45 in this manner, the heat generated by the heat-generating component 15 is efficiently transferred to the inner case lid 23, and the heat is released to the outside of the inner case 11 via the inner case lid 23. can be done.

In the in-vehicle electronic control unit 100B configured as described above, when the air that has flowed into the outer case 12 through the communicating portion 35 flows between the inner case 11 and the outer case 12, the direction of the air is rectified by the rectifying member. 41 arranged. Thereby, inside the outer case 12 , the air flows linearly along the Y direction, which is the extending direction of the straightening member 41 . Therefore, the air flowing into the outer case 12 through the communicating portion 35 can reach the communicating portion 36 while suppressing a decrease in the speed of the air.

Further, the rectifying member 41 extends linearly from the side where the heat generating component 15 is arranged toward the side where the connector component 16 is arranged. Therefore, the flow direction of the air rectified by the rectifying member 41 is a constant direction along the Y direction, and the heat conduction generated on the outer surface of the inner case 11 due to the temperature difference between the heat-generating component 15 and the connector component 16 is the same as the direction of

Here, the heat transfer amount Q can be expressed as the product of the heat flux q and the heat transfer area A. The heat flux q increases due to the temperature difference between the heat-generating component 15 and the connector component 16 . The heat transfer area A does not expand and is constant when no air flow occurs, but increases according to the expansion of the area when air flow occurs. Therefore, when the air flowing into the outer case 12 is rectified by the rectifying member 41, both the heat flux q and the heat transfer area A increase. As a result, the heat transfer amount Q increases significantly. Therefore, heat generated inside the inner case 11 can be efficiently discharged to the outside of the outer case 12 . Moreover, the heat radiation performance of the in-vehicle electronic control unit 100B can be enhanced, and the temperature rise of the heat-generating component 15 can be suppressed.

Further, the rectifying member 41 is composed of heat radiation fins composed of a plurality of plate-like portions. Therefore, the heat generated mainly by the heat-generating component 15 can be released from the surface of the rectifying member 41 to the second space 25 . Then, the air released to the second space 25 can be released to the outside of the outer case 12 along with the flow of air rectified by the rectifying member 41 . Therefore, the heat dissipation performance of the in-vehicle electronic control unit 100B can be further enhanced.

In the second embodiment, of the two

side surfaces

12E and 12F facing each other in the Y direction, which is the extending direction of the rectifying member 41, the side surface 12E is provided with the communicating portion 35, and the side surface 12F is provided with the communicating portion 36. However, the present invention is not limited to this, and for example, like an in-vehicle electronic control unit 100C shown in FIG. In the in-vehicle electronic control unit 100C shown in FIG. 15, the air that has flowed into the outer case 12 is rectified by the rectifying member 41, so that the air flows from the high-temperature heat-generating component 15 side to the low-temperature connector component 16 side. flow is formed. On the other hand, the communicating portion 37 provided on the side surface 12C of the outer case 12 and the communicating portion 38 provided on the other side surface 12D do not face each other in the extending direction of the straightening member 41, unlike the configuration shown in FIG. For this reason, in the in-vehicle electronic control unit 100C shown in FIG. 15, the speed of the air flowing inside the outer case 12 is lower than in the in-vehicle electronic control unit 100B shown in FIG. However, the direction in which the air rectified by the rectifying member 41 flows is a constant direction along the Y direction, and the heat conduction generated on the outer surface of the inner case 11 due to the temperature difference between the heat generating component 15 and the connector component 16. Same as direction. Therefore, the heat transfer amount can be increased by the same principle as described above, and the heat dissipation performance of the in-vehicle electronic control unit 100C can be enhanced. Such an effect can be obtained, for example, by providing a communicating portion 38 on the side surface 12D and providing a communicating portion 36 on the adjacent side surface 12F, as in an in-vehicle electronic control device 100D shown in FIG. , the communication portion 37 is provided on the side surface 12C, and the communication portion 36 is provided on the adjacent side surface 12F.

Further, in the second embodiment, the rectifying member 41 is arranged on the upper surface of the inner case 11, but the rectifying member 41 may be arranged on the lower surface of the inner case 11 without being limited to this. In addition, in the second embodiment, the rectifying member 41 is arranged on one surface of the inner case 11, but the present invention is not limited to this. The rectifying member 41 may be arranged on multiple surfaces of the case 11 . Also, the straightening member 41 may be arranged in the outer case 12 instead of the inner case 11 . However, in order for the rectifying member 41 to function as a radiation fin, it is preferable to arrange the rectifying member 41 in the inner case 11 to which the heat of the heat-generating component 15 is easily conducted.

<Third Embodiment>
FIG. 17 is a perspective view of the in-vehicle electronic control device according to the third embodiment as seen from an oblique direction.
As shown in FIG. 17, the in-vehicle electronic control unit 100E according to the third embodiment has a rectifying member, as compared with the in-vehicle electronic control unit 100B according to the second embodiment (see FIGS. 12 to 14). 41 are common, but the position of providing the communicating portion is different. Specifically, when the in-vehicle electronic control unit 100E is mounted on the vehicle, the in-vehicle electronic control unit 100E is installed with the upper surface 12A side of the outer case 12 as the top surface side and the lower surface 12B side of the outer case 12 as the ground surface side. Assuming such a case, a communicating portion 46 is provided on the upper surface 12A of the outer case 12, and a communicating portion 47 is provided on the opposite lower surface 12B. The communication portion 46 and the communication portion 47 are each configured by a plurality of air holes. This point also applies to other embodiments.

The communicating portion 46 is formed with a smaller area than the communicating portion 47 . Specifically, the communicating portion 46 is formed with an area smaller than half the area of the upper surface 12A, more specifically, an area equal to or less than 1/3 of the area of the upper surface 12A. Further, the communicating portion 46 is provided in the middle portion of the upper surface 12A in the X direction, and is formed in a strip shape long in the Y direction, which is the extending direction of the straightening member 41 . On the other hand, the communicating portion 47 is formed over an area larger than half of the area of the lower surface 12B, more specifically, over substantially the entire area of the lower surface 12B.

In the in-vehicle electronic control device 100E configured as described above, the communicating portion 46 is provided on the upper surface 12A of the outer case 12, and the communicating portion 47 is provided on the lower surface 12B of the outer case 12. For this reason, air can be efficiently taken into the outer case 12 by utilizing the flow of air from the ground side to the top side outside the outer case 12, and the taken-in air can be directed to the outside of the outer case 12. can be discharged efficiently. Therefore, it is possible to realize the in-vehicle electronic control device 100E having high heat dissipation performance.

Further, by forming the communication portion 46 with an area smaller than that of the communication portion 47, dust floating in the air is more likely to be removed from the outer case 12 than when the communication portion 46 is formed with an area equal to that of the communication portion 47. Makes it harder to get inside. Therefore, the function of protecting the inner case 11 from dust and the like can be enhanced.

In addition, as a modification of the third embodiment, as shown in FIG. good too. The communicating portion 46-1 is provided on the side where the heat generating component 15 is arranged, and the communicating portion 46-2 is provided on the side where the connector component 16 is arranged. Further, each of the communicating portions 46-1 and 46-2 is formed in a belt-like shape elongated in the X direction. Even when the communicating portions 46-1 and 46-2 are provided at two locations on the upper surface 12A of the outer case 12, the same effect as described above can be obtained.

<Fourth Embodiment>
FIG. 19 is a cross-sectional view showing an in-vehicle electronic control device according to a fourth embodiment.
As shown in FIG. 19, the in-vehicle electronic control unit 100F according to the fourth embodiment has a communicating part, as compared with the in-vehicle electronic control unit 100B according to the second embodiment (see FIGS. 12 to 14). The size relationship between the hole size S1 of the air hole 35A forming the air hole 35 and the hole size S2 of the air hole 36A forming the communicating portion 36 is characteristic. In this specification, when the communicating portion is configured by a plurality of air holes, the hole size of each air hole is defined by the opening area of the air hole. For example, if the shape of the vent hole 35A is circular, the hole size S1 of the vent hole 35A is defined by πr2. r is the radius of the vent hole 35A.

In the in-vehicle electronic control unit 100F according to the fourth embodiment, the hole size S1 of the vent hole 35A and the hole size S2 of the vent hole 36A satisfy the relationship of S1>S2. Further, in the fourth embodiment, as a more preferable aspect, the hole size S1 of the vent hole 35A and the hole size S2 of the vent hole 36A satisfy the relationship of S2/S1≦0.5.

In the in-vehicle electronic control unit 100F according to the fourth embodiment, the hole size S2 of the vent hole 36A formed on the air outflow side is smaller than the hole size S1 of the vent hole 35A formed on the air inflow side. . Therefore, the speed of the air flowing out of the outer case 12 through the respective ventilation holes 36A can be increased, and the convection of the air outside the outer case 12 can be promoted. Further, as air convection is promoted outside the outer case 12, the speed of the air flowing into the outer case 12 through each of the ventilation holes 35A also increases. As the speed of the air flowing into the outer case 12 increases, the heat transfer rate from the outer surface of the inner case 11 to the air increases. Therefore, the heat dissipation performance of the in-vehicle electronic control unit 100F can be improved. It has been confirmed by simulations conducted by the present inventor that such an effect becomes more remarkable when the relationship S2/S1≦0.5 is satisfied.

<Fifth Embodiment>
FIG. 20 is a perspective view of the in-vehicle electronic control device according to the fifth embodiment as seen from an oblique direction.
The vehicle electronic control unit 100G according to the fifth embodiment differs from the vehicle electronic control unit 100B according to the second embodiment described above (see FIGS. 12 to 14) in that the rectifying member 41 is composed of heat radiation fins. A heat radiation pin 50 is provided instead. The radiating pin 50 radiates heat generated by the heat-generating component 15 as a main heat source to the gap (second space 25) between the inner case 11 and the outer case 12, and is made of a metal such as aluminum or an alloy. ing. The heat radiation pin 50 has a configuration in which a plurality of pins are arranged in a matrix on the inner case lid 23 .

The in-vehicle electronic control unit 100G configured as described above can increase the heat transfer area to the air due to the existence of the heat radiation pin 50, which is an assembly of a plurality of pins. Therefore, the heat dissipation performance of the in-vehicle electronic control unit 100G can be improved.

<Sixth embodiment>
FIG. 21 is a perspective view of an in-vehicle electronic control device according to the sixth embodiment as seen from an oblique direction.
As shown in FIG. 21, the in-vehicle electronic control unit 100H according to the sixth embodiment is different from the in-vehicle electronic control unit 100B (see FIGS. 12 to 14) according to the above-described second embodiment. 41 are common, but the position of providing the communicating portion is different. Specifically, the upper surface 12A of the outer case 12 is provided with a communicating portion 48-1 at one location and a communicating portion 48-2 at another location. In other words, the communicating portions 48-1 and 48-2 are provided at two locations on the outer case 12 with respect to one surface of the outer case 12. As shown in FIG. The number of communicating portions provided on one surface of the outer case 12 may be two or more. Also, the surface on which the communicating portion is provided may be the lower surface 12B of the outer case 12 .

In that case, it is preferable to provide the communicating portions 48-1 and 48-2 at locations separated from each other so that at least one location is on the air inflow side and at least another location is on the air outflow side. In the in-vehicle electronic control unit 100H shown in FIG. 21, the temperature difference between the heat-generating component 15 and the connector component 16 (not shown) causes air flow, that is, convection, in the outer case 12. Therefore, the heat-generating component 15 is arranged. A communicating portion 48-1 is provided on the side where the connector component 16 is arranged, and a communicating portion 48-2 is provided on the side where the connector component 16 is arranged. As a result, even when the communication portions 48-1 and 48-2 are provided only on one surface of the outer case 12, a linear air flow is formed inside the outer case 12, and the electronic control device 100G for the vehicle is operated. Heat dissipation performance can be improved.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration.

100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H... Automotive electronic control device, 10... Circuit board, 15... Heat generating component (electronic component), 16... Connector component (electronic component), 11... Inner Case (first housing) 12 Outer case (second housing) 12A Top surface

12B Bottom surface

12C, 12D, 12E, 12F Side surface 35, 35-1, 35-2, 36 , 37, 38, 46, 46-1, 46-2, 47, 48-1, 48-2... Communicating portion, 35A, 36A... Ventilation hole, 41... Rectification member (radiating fin), 50... Radiation pin

Claims

a circuit board on which electronic components are mounted;
a first housing that accommodates the circuit board;
a second housing that houses the first housing;
In-vehicle electronic control unit.
The in-vehicle electronic control device according to claim 1, wherein the second housing is provided with a communicating portion that communicates the outside and the inside of the second housing.
The in-vehicle electronic control device according to claim 2, wherein the communicating portion is provided at at least two locations on the second housing.
4. The in-vehicle electronic control device according to claim 3, wherein the two locations are located apart from each other.
5. The in-vehicle electronic control device according to claim 4, wherein the two locations are located apart from each other such that at least one location is on the air inflow side and at least another location is on the air outflow side. .
the second housing is a polyhedron,
Of the two locations, at least one location is the first surface of the second housing, and at least another location is the second surface of the second housing that is different from the first surface. The vehicle-mounted electronic control device according to claim 3 .
The in-vehicle electronic control device according to claim 6, wherein the first surface and the second surface are arranged to face each other.
The electronic component includes at least a heat-generating component arranged on one side of the circuit board and a connector component arranged on the other side of the circuit board,
The communicating portion provided at one of the two locations is provided at a position closer to the heat-generating component than the connector component, and the communicating portion provided at the other location is closer to the connector than the heat-generating component. The in-vehicle electronic control device according to claim 3, which is provided at a position close to the component.
4. The in-vehicle electronic control device according to claim 3, further comprising a rectifying member that straightens the direction of air flowing between the first housing and the second housing.
10. The in-vehicle electronic control device according to claim 9, wherein the rectifying member is composed of heat radiation fins.
The electronic component includes at least a heat-generating component arranged on one side of the circuit board and a connector component arranged on the other side of the circuit board,
The on-vehicle electronic control device according to claim 9, wherein the rectifying member extends linearly from the side on which the heat-generating component is arranged toward the side on which the connector component is arranged.
The communicating portion provided at a position closer to the heat-generating component than the connector component is composed of a plurality of ventilation holes each having a first hole size S1,
The communicating portion provided at a position closer to the connector component than the heat-generating component is composed of a plurality of ventilation holes each having a second hole size S2,
The first hole size S1 and the second hole size S2 are
S1>S2
The in-vehicle electronic control device according to claim 8, wherein the relationship of is satisfied.
The first hole size S1 and the second hole size S2 are
S2/S1≦0.5
The in-vehicle electronic control device according to claim 12, wherein the relationship of:
The on-vehicle electronic control device according to claim 12, wherein the vent has a shape having at least one corner.
The in-vehicle electronic control device according to claim 1, further comprising a heat dissipation pin for dissipating heat generated by the electronic component to a gap portion between the first housing and the second housing.