WO2024150331A1

WO2024150331A1 - Electronic control device

Info

Publication number: WO2024150331A1
Application number: PCT/JP2023/000460
Authority: WO
Inventors: 雄亮高橋; 尭之福沢
Original assignee: 日立Astemo株式会社
Priority date: 2023-01-11
Filing date: 2023-01-11
Publication date: 2024-07-18

Abstract

This electronic control device comprises: a circuit board in which an electronic component is mounted on a wiring board on which a wiring pattern is formed; a heat dissipation member made from metal and thermally connected to the electronic component via a heat conduction member; a metal casing which accommodates the circuit board and which is provided with an opening portion formed thereon for the heat dissipation member to be disposed such that the heat dissipation member is partially exposed to the outside; and a conductive member interposed between the heat dissipation member and the casing to close the opening portion of the casing together with the heat dissipation member. The conductive member is a thermal conductive member.

Description

Electronic Control Unit

The present invention relates to an electronic control device, and more specifically, to an electronic control device that houses a circuit board within a housing.

Vehicles such as automobiles are equipped with electronic control devices. Electronic control devices generally have a structure in which a circuit board on which electronic components are mounted is housed inside a housing. In the field of vehicles, the demand for advanced driver assistance systems (hereinafter sometimes referred to as ADAS) and autonomous driving systems (hereinafter sometimes referred to as AD systems) has been increasing in recent years. In electronic control devices used in ADAS and AD systems, electronic components such as CPUs operate at high operating frequencies. For this reason, such electronic control devices have issues such as increased heat generation and the effects of high-frequency electromagnetic noise, and both heat countermeasures and electromagnetic wave countermeasures are required.

The technology described in Patent Document 1 is known as an example of an electronic control device (circuit board) that has both heat countermeasures and electromagnetic wave countermeasures in the field. In the mounting board structure described in Patent Document 1, a metal heat dissipation component (heat receiving part and fins) is mounted on top of a metal shielding frame (first conductive member) provided on a wiring board via a resin-based conductive adhesive member (second conductive member) to cover the electronic components on the wiring board, blocking electromagnetic waves, and a heat transfer path with reduced thermal resistance is ensured by configuring the electronic components to contact the heat dissipation component mounted on the top of the shielding frame only via the TIM member.

JP 2021-44346 A

As mentioned above, electronic control devices generally house a circuit board on which electronic components are mounted in a housing. Here, consider an electronic control device in which the mounting board structure described in Patent Document 1 is housed in a housing. A heat dissipation component that is thermally connected to the electronic component via a TIM member is positioned, for example, so that the fins are exposed to the outside of the housing through an opening provided in the housing.

In this type of configuration, heat from the electronic components is dissipated from the fins of the heat dissipation component to the outside of the housing via the TIM component. However, as mentioned above, electronic control devices used in ADAS and AD systems have the issue of increased heat generation, and high heat dissipation performance is required. There are concerns that insufficient heat dissipation may occur with a heat dissipation path in which heat from electronic components is dissipated to the outside of the housing only from the heat dissipation component. For this reason, it is preferable to further improve heat dissipation performance.

Furthermore, in such a configuration, a gap is created between the housing with the opening and the heat dissipation component, connecting the inside and outside of the housing. This gap becomes a path for electromagnetic noise to leak outside the housing or enter inside the housing. In other words, an electronic control device with such a configuration has reduced electromagnetic compatibility.

The present invention was made to solve the above problems, and its purpose is to provide an electronic control device that can improve both electromagnetic compatibility and heat dissipation performance.

The present application includes multiple means for solving the above problems. As one example, an electronic control device includes a circuit board having a wiring board on which a wiring pattern is formed and electronic components mounted on the wiring board, a metal heat dissipation member thermally connected to the electronic components via a thermally conductive member, a metal housing that houses the circuit board and has an opening in which the heat dissipation member is disposed so that a portion of the heat dissipation member is exposed to the outside, and a conductive member that is interposed between the heat dissipation member and the housing and that covers the opening of the housing together with the heat dissipation member, the conductive member being a thermally conductive member.

According to the present invention, by interposing a conductive member between the heat dissipation member and the housing and blocking the opening of the housing together with the heat dissipation member, the circuit board is surrounded by the metal housing, the metal heat dissipation member, and the conductive member, so that it is possible to suppress the leakage of electromagnetic noise to the outside of the housing and the intrusion into the inside of the housing. Furthermore, since the conductive member interposed between the heat dissipation member and the housing has thermal conductivity, it is possible to ensure a heat dissipation path to the housing via the conductive member in addition to the heat dissipation path from the electronic component to the heat dissipation member. Therefore, it is possible to improve both electromagnetic compatibility and heat dissipation.
Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments.

1 is a schematic perspective view showing an external appearance of an electronic control device according to a first embodiment of the present invention; 2 is a schematic perspective view showing the electronic control device according to the first embodiment shown in FIG. 1 in an exploded state. FIG. 2 is a plan view of the electronic control device according to the first embodiment shown in FIG. 1 . 4 is a plan view showing the electronic control device according to the first embodiment shown in FIG. 3 with a case body of a housing removed. FIG. 4 is a schematic cross-sectional view of the electronic control device according to the first embodiment shown in FIG. 3, as viewed from the VV arrow direction. 5 is a schematic cross-sectional view of an electronic control device according to a second embodiment of the present invention, as viewed in the same direction as the VV arrows shown in FIG. 3. 7 is a plan view showing the electronic control device according to the second embodiment shown in FIG. 6 with a case body of the housing removed. FIG. 1 is a schematic cross-sectional view illustrating a new problem in the electronic control device according to the first embodiment. FIG. 7 is a schematic cross-sectional view of an electronic control device according to a third embodiment of the present invention, as viewed in the same direction as the VV arrows shown in FIG. 3. 10 is a plan view showing the electronic control device according to the third embodiment shown in FIG. 9 with a case body of the housing removed. FIG. FIG. 13 is a plan view showing an electronic control device according to a first modified example of the third embodiment with a case body of the housing removed. FIG. 13 is a plan view showing an electronic control device according to a second modified example of the third embodiment with a case body of the housing removed. 7 is a schematic cross-sectional view of an electronic control device according to a fourth embodiment of the present invention, as viewed in the same direction as the VV arrows shown in FIG. 3.

Below, an embodiment of an electronic control device of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functions or configurations will be given the same reference numerals, and duplicated descriptions will be omitted.

[First embodiment]
First, the configuration and structure of an electronic control device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a schematic perspective view showing the appearance of the electronic control device according to the first embodiment. FIG. 2 is a schematic perspective view showing the electronic control device according to the first embodiment shown in FIG. 1 in an exploded state. FIG. 3 is a plan view of the electronic control device according to the first embodiment shown in FIG. 1. FIG. 4 is a plan view showing the electronic control device according to the first embodiment shown in FIG. 3 in a state in which the case body of the housing is removed. FIG. 5 is a schematic cross-sectional view of the electronic control device according to the first embodiment shown in FIG. 3 as seen from the V-V arrow. In FIGS. 1 and 2, the electronic control device 1 is mounted on, for example, a vehicle (not shown) and is used in an ADAS or AD system. The electronic control device 1 includes a circuit board 2 constituting an electronic circuit and a housing 3 accommodating the circuit board 2.

As shown in Figures 2 and 5, the circuit board 2 has a printed wiring board 11 on which a wiring pattern (not shown) is formed, and a plurality of electronic components 12 (only one is shown in Figures 2 and 5) mounted on the printed wiring board 11. Note that the circuit board 2 shown in Figures 2 and 5 is a simplified representation of the configuration necessary for explaining this embodiment, and other configurations are omitted.

The printed wiring board 11 has both a first surface 11a and a second surface 11b on which electronic components can be mounted. The printed wiring board 11 can be configured as either a single-sided board in which a wiring pattern is formed on only one of the first surface 11a and the second surface 11b, or a double-sided board in which a wiring pattern is formed on both surfaces. In the printed wiring board 11 shown in Figures 2 and 5, the first surface 11a is configured as a mounting surface for electronic components 12.

The electronic component 12 generates a large amount of heat and requires heat countermeasures. For example, it is an electronic component that can operate at a high operating frequency such as a CPU, and consumes very high power due to its high speed processing. The electronic component 12 has a bottom surface 12a that is electrically connected to the wiring pattern of the printed wiring board 11, and a top surface 12b located on the opposite side of the bottom surface 12a. The electronic component 12 is a component formed in a rectangular shape, for example, as shown in FIG. 2.

2 and 5, the housing 3 is composed of a case body 21 having an opening 21a through which the circuit board 2 can be inserted and a storage space 21b in which the circuit board 2 can be stored, and a cover 22 attached to the case body 21 so as to cover the opening 21a of the case body 21. The housing 3 is formed of a metal material and functions as an electromagnetic shield for the circuit board 2. The case body 21 has an opposing wall 24 facing the printed wiring board 11 (first surface 11a), a peripheral wall 25 rising from the outer periphery of the opposing wall 24 and surrounding the outer periphery of the circuit board 2, and a plurality of mounting portions 26 provided at the corners of the peripheral wall 25, and the opposing wall 24, the peripheral wall 25, and the plurality of mounting portions 26 are integrally formed. The circuit board 2 is fixed to the mounting portion 26 of the case body 21 by a first screw 7. A heat dissipation opening 28 is formed in the portion of the facing wall 24 of the case body 21 facing the upper surface 12b of the electronic component 12 to dissipate heat from the electronic component 12 to the outside of the housing 3. The cover 22 is configured to face, for example, the printed wiring board 11 (second surface 11b).

The electronic control device 1 further includes a heat sink 4 for dissipating heat from the electronic component 12 to the outside of the housing 3, as shown in Figures 2 and 5. The heat sink 4 includes a heat dissipation member 31 disposed in the heat dissipation opening 28 of the housing 3 so that a portion of the heat sink 4 is exposed to the outside of the housing 3, and a heat conductive member 32 interposed between the heat dissipation member 31 and the electronic component 12 to thermally connect the heat dissipation member 31 and the electronic component 12. In other words, the heat sink 4 is configured to thermally connect the heat dissipation member 31 to the electronic component 12 via the heat conductive member 32.

The heat dissipation member 31 is formed, for example, from a metal material having a higher thermal conductivity than the metal housing 3. The heat dissipation member 31 has a plate-shaped base portion 34 that is in direct contact with the heat conduction member 32, a plurality of pedestal portions 35 provided on the portion of the base portion 34 on the electronic component 12 side (one side), and a plurality of heat dissipation fins 36 provided on the portion of the base portion 34 on the heat dissipation opening 28 side of the housing 3 (the other side). This reduces costs compared to a configuration in which the housing 3 is formed from the same metal material with high thermal conductivity as the heat dissipation member 31 and connected to the electronic component via the heat conduction member 32.

The base portion 34 is disposed so as to be located between the electronic component 12 and the peripheral portion that forms the heat dissipation opening 28 in the opposing wall 24 of the housing 3. As shown in Figures 3 to 5, for example, the base portion 34 is configured so as to be larger than the upper surface 12b of the electronic component 12 and the heat dissipation opening 28 of the housing 3. Furthermore, as shown in Figures 2 and 4, for example, the base portion 34 is formed in a rectangular shape when viewed from a direction perpendicular to the printed wiring board 11.

As shown in FIG. 5, the plurality of pedestals 35 are fixed on the printed wiring board 11 to support the base portion 34, and are configured to be longer than the height from the first surface 11a of the printed wiring board 11 to the top surface of the electronic component 12. As shown in FIGS. 4 and 5, when viewed from a direction perpendicular to the printed wiring board 11, the pedestals 35 are disposed at a position outside the plurality of heat dissipation fins 36 and at a distance from the outer periphery of the electronic component 12. As shown in FIGS. 2, 4, and 5, for example, each pedestal 35 is configured to extend from a part of the outer periphery of the base portion 34 toward the printed wiring board 11. More specifically, each pedestal 35 protrudes from each of the four corners of the rectangular base portion 34. The pedestal 35 is fastened to the printed wiring board 11 by the second screw 8, and the heat dissipation member 31 is fixed to the printed wiring board 11.

The heat dissipation fins 36 extend from the center of the base portion 34 (a position overlapping with the electronic component 12 when viewed from a direction perpendicular to the printed wiring board 11) toward the heat dissipation opening 28 of the housing 3, and are configured to be exposed to the outside of the housing 3 through the heat dissipation opening 28. The number of heat dissipation fins 36 (five in Figures 3 and 5) is set according to the size of the heat dissipation opening 28, for example.

The heat conducting member 32 is interposed between the upper surface 12b of the electronic component 12 and the base portion 34 of the heat dissipation member 31. The heat conducting member 32 is, for example, made primarily of resin with thermally conductive filler added. For example, a TIM (Thermal Interface Material) such as a heat dissipation grease or a heat conductive sheet made primarily of silicone, acrylic, epoxy, urethane, etc. is used as the heat conducting member 32.

In this embodiment, as shown in FIG. 5, the heat dissipation fins 36 extending from the base portion 34 of the heat dissipation member 31 are exposed to the outside of the housing 3 through the heat dissipation openings 28 of the housing 3. Therefore, a gap C that connects the inside and outside of the housing 3 exists between the peripheral portion that forms the heat dissipation openings 28 in the opposing wall 24 of the housing 3 and the base portion 34 of the heat dissipation member 31.

In this embodiment, as shown in Figures 2, 4, and 5, a conductive member 5 is disposed so as to close the above-mentioned gap C that connects the inside and outside of the housing 3. The conductive member 5 is configured to surround the circuit board 2 in a sealed state together with the metal housing 3 and the metal heat dissipation member 31, and functions as part of an electromagnetic wave shield that suppresses the leakage of electromagnetic noise to the outside of the housing 3 and the intrusion of electromagnetic noise into the inside of the housing 3.

Specifically, the conductive member 5 functions as an annular sealing member interposed between the peripheral portion forming the heat dissipation opening 28 in the opposing wall 24 of the housing 3 and the opposing base portion 34 of the heat dissipation member 31, and is configured to block the heat dissipation opening 28 of the housing 3 together with the heat dissipation member 31. The conductive member 5 is configured as a rectangular annular member arranged along the outer peripheral edge portion of the base portion 34 of the heat dissipation member 31, as shown in Figs. 2 and 4, for example. Also, as shown in Figs. 4 and 5, for example, the conductive member 5 is arranged at a position overlapping with the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from a direction perpendicular to the printed wiring board 11. The conductive member 5 is assembled, for example, in a state where it is sandwiched and pressed between the opposing wall 24 of the housing 3 and the base portion 34 of the heat dissipation member 31.

The conductive member 5 is configured, for example, as a member that has electrical conductivity as well as thermal conductivity. Specifically, the conductive member 5 is a spreadable adhesive that is configured to contain a conductive filler that has been metal-plated, and whose main material is, for example, a resin such as silicone, acrylic, epoxy, or urethane. By containing a conductive filler that has been metal-plated, it is possible to reliably ensure electrical conductivity and thermal conductivity. Furthermore, by using a resin as the main material, it is possible to ensure applicability, storability, and mechanical strength. The conductive member 5 can be automatically applied, for example, by a dispenser.

The conductive member 5 can also be made of a CIPG (Cured-In-Place Gasket). There are various types of CIPG, such as moisture-curing, heat-curing, and UV-curing. A liquid gasket is obtained by applying a liquid sealant (adhesive) to one sealing surface (the inner surface of the opposing wall 24 of the housing 3, or the surface of the base part 34 of the heat dissipation member 31) and curing it, and then pressing it against the other sealing surface (the surface of the base part 34 of the heat dissipation member 31, or the inner surface of the opposing wall 24 of the housing 3) to make it adhere to the other sealing surface. The conductive member 5 as a CIPG does not allow the applied liquid sealant to drip onto the printed wiring board 11. The conductive member 5 as a CIPG also functions as a gasket by pressing the cured liquid sealant to make it adhere to the other sealing surface, and has a lower impedance than before it is pressed. That is, the conductive member 5 as the CIPG is sandwiched and pressed between the opposing wall 24 of the housing 3 and the base portion 34 of the heat dissipation member 31, improving the electromagnetic wave shielding performance.

Next, the effects of the electronic control device according to the first embodiment will be described with reference to FIG. 5. In FIG. 5, the white arrows indicate electromagnetic noise.

In the electronic control device 1 according to this embodiment, as shown in FIG. 5, the base portion 34, which is a part of the heat dissipation member 31, is thermally connected to the electronic component 12 via the heat conductive member 32, and the heat dissipation fins 36, which are a part of the heat dissipation member 31, are exposed to the outside of the housing 3 via the heat dissipation openings 28 of the housing 3. With this configuration, heat generated in the electronic component 12 is transferred to the base portion 34 of the heat dissipation member 31 via the heat conductive member 32 and is released from the heat dissipation fins 36 to the outside of the housing 3. In other words, the heat dissipation performance of the electronic control device 1 is ensured by ensuring a heat transfer path from the heat conductive member 32 to the heat dissipation fins 36 of the heat dissipation member 31 as a heat dissipation path from the electronic component 12 to the outside of the housing 3.

However, in this type of structure, a gap C that connects the inside and outside of the housing 3 is formed between the peripheral portion that forms the heat dissipation opening 28 in the opposing wall 24 of the housing 3 and the base portion 34 of the heat dissipation member 31. This gap C can be a path through which electromagnetic noise generated inside the housing 3 leaks out to the outside of the housing 3, and a path through which electromagnetic noise generated outside the housing 3 penetrates into the inside of the housing 3 (see the white arrow). In other words, if the gap C that connects the inside and outside of the housing 3 remains, the electromagnetic shielding performance of the electronic control device 1 will be reduced.

In this embodiment, as shown in FIG. 5, the conductive member 5 is interposed between the opposing wall 24 of the housing 3 and the base portion 34 of the heat dissipation member 31 to close the gap C. That is, the heat dissipation opening 28 of the housing 3 is closed by the heat dissipation member 31 and the conductive member 5, and the circuit board 2 is surrounded by the housing 3, the heat dissipation member 31, and the conductive member 5. Therefore, the metal housing 3, the metal heat dissipation member 31, and the conductive member 5 surrounding the circuit board 2 function as an electromagnetic wave shield. This makes it possible to suppress the leakage of electromagnetic noise (white arrow) generated on the circuit board 2 to the outside of the housing 3, and to suppress the intrusion of electromagnetic noise (white arrow) from the outside of the housing 3 to the inside.

Furthermore, in this embodiment, the conductive member 5 is configured as a member having thermal conductivity. This means that the housing 3 is thermally connected to the base portion 34 of the heat dissipation member 31 via the conductive member 5. With this configuration, the heat transferred from the electronic component 12 to the base portion 34 of the heat dissipation member 31 via the thermally conductive member 32 is further transferred to the opposing wall 24 of the housing 3 via the conductive member 5 and released to the outside of the housing 3. In other words, as a heat dissipation path from the electronic component 12 to the outside of the housing 3, a heat transfer path from the heat dissipation member 31 to the housing 3 via the conductive member 5 is further secured in addition to the heat transfer path to the heat dissipation fins 36 of the heat dissipation member 31, so that the heat dissipation performance of the electronic control device 1 can be improved.

As described above, the electronic control device 1 according to the first embodiment includes a circuit board 2 having a printed wiring board 11 (wiring board) on which a wiring pattern is formed and electronic components 12 mounted on the printed wiring board 11 (wiring board), a metal heat dissipation member 31 thermally connected to the electronic components 12 via a heat conductive member 32, a metal housing 3 that houses the circuit board 2 and has a heat dissipation opening 28 (opening) in which the heat dissipation member 31 is arranged so that a portion of the heat dissipation member 31 is exposed to the outside, and a conductive member 5 that is interposed between the heat dissipation member 31 and the housing 3 and that, together with the heat dissipation member 31, blocks the heat dissipation opening 28 (opening) of the housing 3. The conductive member 5 is a member that has thermal conductivity.

With this configuration, the conductive member 5 is interposed between the heat dissipation member 31 and the housing 3 to block the heat dissipation opening 28 (opening) of the housing 3 together with the heat dissipation member 31, and the circuit board 2 is surrounded by the metal housing 3, the metal heat dissipation member 31, and the conductive member 5, so that it is possible to suppress the leakage of electromagnetic noise to the outside of the housing 3 and the intrusion into the inside of the housing 3. Furthermore, since the conductive member 5 interposed between the heat dissipation member 31 and the housing 3 has thermal conductivity, it is possible to ensure a heat dissipation path to the housing 3 via the conductive member 5 in addition to the heat dissipation path from the electronic component 12 to the heat dissipation member 31. Therefore, it is possible to improve both electromagnetic compatibility and heat dissipation.

In addition, in this embodiment, the conductive member 5 is made of CIPG formed by hardening a liquid gasket. With this configuration, the liquid component before hardening does not drip onto the printed wiring board 11 when the conductive member 5 is assembled.

In addition, in this embodiment, the conductive member 5 is configured to contain conductive filler that has been metal-plated. With this configuration, the conductivity of the conductive member 5 is reliably exhibited, so that the conductive member 5 reliably functions as an electromagnetic wave shield.

In addition, in this embodiment, the conductive member 5 is a member whose main material is resin. With this configuration, it is possible to ensure the mechanical strength of the conductive member 5 interposed between the heat dissipation member 31 and the housing 3.

Second Embodiment
Next, an electronic control device according to a second embodiment of the present invention will be described with reference to the drawings. First, the configuration and structure of the electronic control device according to the second embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a schematic cross-sectional view of the electronic control device according to the second embodiment of the present invention, seen from the same direction as the V-V arrow shown in Fig. 3. Fig. 7 is a plan view showing the electronic control device according to the second embodiment shown in Fig. 6 with the case body of the housing removed.

The main differences between the electronic control device 1A according to the second embodiment and the first embodiment are as follows. In the electronic control device 1 according to the first embodiment, the annular conductive member 5 is arranged at a position overlapping the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from a direction perpendicular to the printed wiring board 11 (see FIGS. 4 and 5). In contrast, in the electronic control device 1A according to the second embodiment shown in FIGS. 6 and 7, the annular conductive member 5A is arranged at a position outside the multiple pedestal portions 35 of the heat dissipation member 31A when viewed from a direction perpendicular to the printed wiring board 11, and the size of the heat dissipation opening 28A of the housing 3A and the size of the base portion 34A of the heat dissipation member 31A are changed accordingly. The rest of the structure of the electronic control device 1A according to the second embodiment is similar to the structure of the electronic control device 1 according to the first embodiment, and a description thereof will be omitted.

Specifically, when viewed from a direction perpendicular to the printed wiring board 11, the heat dissipation member 31A is formed such that the base portion 34A extends outward beyond the multiple pedestal portions 35 arranged in the same manner as in the first embodiment. In other words, the multiple pedestal portions 35 are located inside the outer periphery of the base portion 34A. Note that the base portion 34A is formed in a rectangular shape when viewed from a direction perpendicular to the printed wiring board 11, similar to the first embodiment.

The conductive member 5A is disposed along the outer peripheral edge of the base portion 34A of the heat dissipation member 31A. In other words, the annular conductive member 5A is disposed outside the multiple pedestal portions 35 of the heat dissipation member 31A when viewed from a direction perpendicular to the printed wiring board 11, and is formed to have a larger diameter than the annular conductive member 5 according to the first embodiment. Note that the conductive member 5A is configured as a rectangular annular member, similar to the first embodiment.

As shown in FIG. 6, the heat dissipation opening 28A of the housing 3A is formed to be larger than the heat dissipation opening 28 of the housing 3 according to the first embodiment, depending on the diameter of the annular conductive member 5A. By enlarging the size of the heat dissipation opening 28A, it is possible to increase the number of heat dissipation fins 36 of the heat dissipation member 31A. However, the number of heat dissipation fins 36 shown in FIG. 6 is the same as the number of heat dissipation fins 36 of the heat dissipation member 31 of the first embodiment.

Next, the effects of the electronic control device according to the second embodiment will be explained using Figs. 6 to 8, taking into account the new issues with respect to the configuration of the first embodiment. First, the new issues with respect to the configuration of the first embodiment will be explained using Fig. 8. Fig. 8 is a schematic cross-sectional view explaining the new issues with the electronic control device according to the first embodiment.

In the electronic control device 1 according to the first embodiment, as shown in FIG. 8, the conductive member 5 is sandwiched and pressed between the base portion 34 of the heat dissipation member 31 and the opposing wall 24 of the housing 3. This can also be said to be a state in which the base portion 34 of the heat dissipation member 31 is pressed against the opposing wall 24 of the housing 3 via the conductive member 5.

In the first embodiment, when viewed from the orthogonal direction of the printed wiring board 11, the conductive member 5 is disposed at a position overlapping the multiple pedestal portions 35 of the heat dissipation member 31 (see also FIG. 4). In this configuration, the pressing force acting on the base portion 34 of the heat dissipation member 31 from the opposing wall 24 of the housing 3 via the conductive member 5 is transmitted to the printed wiring board 11 through the pedestal portions 35 located on the line of action of the pressing force. This raises the concern that high distortion may occur near the pedestal portions 35 on the printed wiring board 11. If high distortion occurs near the pedestal portions 35 on the printed wiring board 11, distortion may occur in the solder joints of the electronic components 12 connected to the printed wiring board 11, and the solder life of the electronic components 12 may be reduced.

In contrast, in the second embodiment, as shown in FIG. 6 and FIG. 7, the conductive member 5A is disposed so as to be sandwiched between the base portion 34A of the heat dissipation member 31A and the housing 3A, and is disposed at a position (not overlapping) outside the multiple pedestal portions 35 of the heat dissipation member 31A when viewed from the perpendicular direction of the printed wiring board 11. In this configuration, as shown in FIG. 6, the pressing force acting on the base portion 34A of the heat dissipation member 31A from the opposing wall 24 of the housing 3A through the conductive member 5A is transmitted to the printed wiring board 11 through the pedestal portion 35 located at a position shifted from the line of action of the pressing force. Therefore, the stress generated near the pedestal portion 35 in the printed wiring board 11 is smaller than in the configuration of the first embodiment, so that the distortion generated in the printed wiring board 11 due to the pressing force acting from the opposing wall 24 of the housing 3A through the conductive member 5A is suppressed more than in the first embodiment. As a result, the distortion generated in the solder joint of the electronic component 12 is also suppressed, so that the decrease in the solder life can be suppressed.

According to the second embodiment described above, as in the first embodiment, by interposing a conductive member 5A between the heat dissipation member 31A and the housing 3A and blocking the heat dissipation opening 28A (opening) of the housing 3A together with the heat dissipation member 31A, it is possible to suppress the leakage of electromagnetic noise to the outside of the housing and the intrusion into the inside of the housing. Furthermore, since the conductive member 5A interposed between the heat dissipation member 31A and the housing 3A has thermal conductivity, it is possible to ensure a heat dissipation path to the housing 3A via the conductive member 5A in addition to the heat dissipation path from the electronic component 12 to the heat dissipation member 31A. Therefore, it is possible to improve both electromagnetic compatibility and heat dissipation.

In the electronic control device 1A according to this embodiment, similarly to the first embodiment, the heat dissipation member 31A has a base portion 34A that is in direct contact with the heat conductive member 32, a plurality of pedestal portions 35 that are provided on the electronic component 12 side of the base portion 34A and fixed on the printed wiring board 11 (wiring board) to support the base portion 34A, and a heat dissipation fin 36 that is provided on the heat dissipation opening 28A (opening) side of the base portion 34A and is exposed to the outside of the housing 3A through the heat dissipation opening 28A (opening). Furthermore, the conductive member 5A is disposed so as to be sandwiched between the base portion 34A of the heat dissipation member 31A and the housing 3A, and is disposed in a position that does not overlap with the plurality of pedestal portions 35 of the heat dissipation member 31A when viewed from a direction perpendicular to the printed wiring board 11 (wiring board).

With this configuration, the multiple pedestal portions 35 are positioned at positions offset from the line of action of the force acting on the base portion 34A of the heat dissipation member 31A from the housing 3A via the conductive member 5A, so that the distortion generated in the printed wiring board 11 (wiring board) can be reduced more than in the first embodiment.

In addition, in this embodiment, the conductive member 5A is positioned outside the multiple pedestal portions 35 of the heat dissipation member 31A when viewed from a direction perpendicular to the printed wiring board 11 (wiring board).

With this configuration, it is possible to enlarge the heat dissipation opening 28A (opening) of the housing 3A according to the size of the conductive member 5A. By enlarging the heat dissipation opening 28A (opening), it is possible to increase the number of heat dissipation fins 36 of the heat dissipation member 31A, and the heat dissipation performance of the electronic control device 1A can be further improved.

[Third embodiment]
Next, an electronic control device according to a third embodiment of the present invention will be described with reference to Figures 9 and 10. Figure 9 is a schematic cross-sectional view of the electronic control device according to the third embodiment, as seen from the same direction as the V-V arrow shown in Figure 3. Figure 10 is a plan view showing the electronic control device according to the third embodiment shown in Figure 9 with the case body of the housing removed.

The main differences between the electronic control device 1B according to the third embodiment and the first embodiment are as follows. In the electronic control device 1 according to the first embodiment, the annular conductive member 5 is arranged at a position overlapping the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from a direction perpendicular to the printed wiring board 11 (see Figures 4 and 5). In contrast, in the electronic control device 1B according to the third embodiment shown in Figures 9 and 10, the annular conductive member 5B is arranged at a position inside the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from a direction perpendicular to the printed wiring board 11, and the size of the heat dissipation opening 28B of the housing 3B is changed accordingly. The rest of the structure of the electronic control device 1B according to the second embodiment is similar to the structure of the electronic control device 1 according to the first embodiment, and a description thereof will be omitted.

Specifically, the annular conductive member 5B is disposed in a position inside the multiple pedestal portions 35 of the heat dissipation member 31 and outside the multiple heat dissipation fins 36 when viewed from a direction perpendicular to the printed wiring board 11. In other words, the annular conductive member 5B is formed to have a smaller diameter than the annular conductive member 5 according to the first embodiment. Furthermore, the conductive member 5B is disposed so as to follow the outer peripheral edge of the electronic component 12 when viewed from a direction perpendicular to the printed wiring board 11. Note that the conductive member 5B is configured as a rectangular annular member, similar to the first embodiment.

As shown in FIG. 9, the heat dissipation opening 28B of the housing 3B is formed to be smaller than the heat dissipation opening 28 of the housing 3 according to the first embodiment, depending on the diameter of the annular conductive member 5B. However, even if the heat dissipation opening 28B is made smaller than the configuration of the first embodiment, there is no need to reduce the number of heat dissipation fins 36, because the annular conductive member 5B is positioned outside the multiple heat dissipation fins 36 of the heat dissipation member 31.

In the third embodiment, the conductive member 5B is disposed so as to be sandwiched between the base portion 34 of the heat dissipation member 31 and the housing 3B, and is disposed in a position (not overlapping) inside the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from a direction perpendicular to the printed wiring board 11. In this configuration, as shown in FIG. 9, the pressing force acting on the base portion 34 of the heat dissipation member 31 from the opposing wall 24 of the housing 3B through the conductive member 5B is transmitted to the printed wiring board 11 through the pedestal portion 35 located at a position shifted from the line of action of the pressing force. Therefore, the stress generated near the pedestal portion 35 in the printed wiring board 11 is smaller than in the configuration of the first embodiment (see FIG. 8), so that the distortion generated in the printed wiring board 11 due to the pressing force acting from the opposing wall 24 of the housing 3B through the conductive member 5B is suppressed more than in the first embodiment. As a result, the distortion generated in the solder joint of the electronic component 12 is also suppressed, so that the decrease in the solder life can be suppressed.

Furthermore, in this configuration, the length of each of the four sides of the rectangular conductive member 5B shown in FIG. 10 is shorter than the length of each of the four sides of the rectangular conductive member 5 of the first embodiment (see FIG. 4). Therefore, the amount of conductive member 5B made of adhesive or CIPG that needs to be applied can be reduced compared to the first embodiment.

In addition, in this embodiment, as in the first embodiment, the heat dissipation member 31 is structured such that the four corners of the base portion 34 are supported by the pedestal portions 35. When the conductive member 5 is disposed in a position overlapping the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from the orthogonal direction of the printed wiring board 11, as in the configuration of the first embodiment shown in FIG. 8, the base portion 34 deforms due to heat from the electronic component 12, and the amount of thermal deformation increases toward the inside (center) away from the pedestal portions 35.

In contrast, in the present embodiment, as described above, the conductive member 5B is disposed at a position inside the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from a direction perpendicular to the printed wiring board 11. In this configuration, as shown in FIG. 9, the pressing force from the opposing wall 24 of the housing 3B acts on the region inside (toward the center) the multiple pedestal portions 35 in the base portion 34 of the heat dissipation member 31 via the conductive member 5B. This pressing force via the conductive member 5B can suppress thermal deformation of the region inside (toward the center) the multiple pedestal portions 35 in the base portion 34 more than in the first embodiment. When the thermal deformation of the base portion 34 is suppressed, the deformation of the heat conductive member 32 that is in close contact with the electronic component 12 and the base portion 34 is suppressed, and the heat dissipation can be further improved.

[Modification of the third embodiment]
Next, electronic control devices according to first and second modified examples of the third embodiment of the present invention will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is a plan view showing an electronic control device according to a first modified example of the third embodiment with the case body of the housing removed. Fig. 12 is a plan view showing an electronic control device according to a second modified example of the third embodiment with the case body of the housing removed.

The electronic control device 1C according to the first modified example of the third embodiment shown in FIG. 11 differs from the third embodiment (see FIG. 10) in that the annular conductive member 5C is formed in a circular shape when viewed from a direction perpendicular to the printed wiring board 11, and that the annular conductive member 5C is disposed at a position outside the outer periphery of the electronic component 12. Note that, like the conductive member 5B according to the third embodiment, the conductive member 5C according to the first modified example is disposed at a position inside the multiple pedestal portions 35 of the heat dissipation member 31 and outside the multiple heat dissipation fins 36 when viewed from a direction perpendicular to the printed wiring board 11. The rest of the structure of the electronic control device 1C according to the first modified example is similar to the structure of the electronic control device 1B according to the third embodiment, and a description thereof will be omitted.

When the conductive member 5C is composed of a spreadable adhesive or CIPG, the adhesive or liquid sealant that is later cured as the conductive member 5C is automatically applied by a dispenser. In the third embodiment described above, the conductive member 5B is formed as a rectangular ring-shaped member, so in order to make the thickness of the conductive member 5B approximately constant, the application speed of the conductive member 5B (adhesive or liquid sealant) needs to be changed between the straight line portion and the corner portion of the rectangle, making it difficult to adjust the application speed. In contrast, in the first modification of the third embodiment, the conductive member 5C is formed as a circular ring-shaped member, so the thickness of the conductive member 5C can be made approximately constant by keeping the application speed of the conductive member 5C (adhesive or liquid sealant) approximately constant. In other words, it is easy to adjust the application speed.

The electronic control device 1D according to the second modification of the third embodiment shown in FIG. 12 differs from the third embodiment (see FIG. 10) in that, when viewed from a direction perpendicular to the printed wiring board 11, the conductive member 5D is arranged along the outer periphery of the base portion 34 of the heat dissipation member 31 while avoiding overlap with the multiple pedestal portions 35 of the heat dissipation member 31. Note that, like the conductive member 5B according to the third embodiment, the conductive member 5D according to the second modification is arranged inwardly of the multiple pedestal portions 35 of the heat dissipation member 31 and outwardly of the multiple heat dissipation fins 36 when viewed from a direction perpendicular to the printed wiring board 11. The rest of the structure of the electronic control device 1D according to the second modification of the third embodiment is similar to the structure of the electronic control device 1B according to the third embodiment, and a description thereof will be omitted.

In the second modified example of the third embodiment, the conductive member 5D is arranged along the outer periphery of the base portion 34 of the heat dissipation member 31 at a position other than the corners. That is, since the conductive member 5D is located on the base portion 34 of the heat dissipation member 31 outside the conductive member 5B of the third embodiment, it is not necessary to reduce the size of the heat dissipation opening 28 of the housing 3 to the size of the heat dissipation opening 28B of the housing 3B of the third embodiment. Therefore, there is no need to reduce the number of heat dissipation fins 36 of the heat dissipation member 31 according to the size of the heat dissipation opening 28. In other words, in a configuration in which the conductive member 5D is arranged at a position inside the multiple pedestal portions 35 of the heat dissipation member 31, it is possible to maximize the size of the heat dissipation opening 28 of the housing 3. Therefore, it is not necessary to reduce the number of heat dissipation fins 36 of the heat dissipation member 31 according to the size of the heat dissipation opening 28.

According to the third embodiment and its modified example described above, similar to the first embodiment,

conductive members

5B, 5C, 5D are interposed between the heat dissipation member 31 and the

housings

3, 3B to block the

heat dissipation openings

28, 28B (openings) of the

housings

3, 3B together with the heat dissipation member 31, thereby suppressing the leakage of electromagnetic noise to the outside of the housing and the intrusion into the inside of the housing. Furthermore, since the

conductive members

5B, 5C, 5D interposed between the heat dissipation member 31 and the

housings

3, 3B have thermal conductivity, a heat dissipation path to the

housings

3, 3B via the

conductive members

5B, 5C, 5D can be secured in addition to the heat dissipation path from the electronic component 12 to the heat dissipation member 31. Therefore, both electromagnetic compatibility and heat dissipation can be improved.

Also, as described above, in the third embodiment and its modified example, when viewed from a direction perpendicular to the printed wiring board 11 (wiring board), the

conductive members

5B, 5C, and 5D are positioned inside the multiple pedestal portions 35 of the heat dissipation member 31.

With this configuration, the pressing force from the

housings

3 and 3B acts on the region inside the multiple pedestal portions 35 on the base portion 34 of the heat dissipation member 31 via the

conductive members

5B, 5C, and 5D, making it possible to suppress thermal deformation of that region more than in the first embodiment. By suppressing thermal deformation of the base portion 34, deformation of the heat conductive member 32 is reduced, thereby improving heat dissipation.

In addition, in the third embodiment described above, when viewed from a direction perpendicular to the printed wiring board 11 (wiring board), the conductive member 5B is arranged so as to follow the outer periphery of the electronic component 12. With this configuration, it is possible to minimize the amount of conductive member 5B used while covering the outer edge of the heat generating region of the electronic component 12.

In addition, in the first modified example of the third embodiment described above, the conductive member 5C is formed in a circular ring shape. With this configuration, the coating speed can be easily adjusted when the conductive member 5C is made of a coatable material.

Furthermore, in the second modified example of the third embodiment described above, when viewed from a direction perpendicular to the printed wiring board 11 (wiring board), the conductive member 5D is arranged along the outer periphery of the base portion 34 while avoiding the positions of the multiple pedestal portions 35 of the heat dissipation member 31. With this configuration, it is possible to suppress distortion of the printed wiring board 11 and suppress thermal deformation of the base portion 34 of the heat dissipation member 31 without reducing the number of heat dissipation fins 36 of the heat dissipation member 31.

[Fourth embodiment]
Next, an electronic control device according to a fourth embodiment of the present invention will be described with reference to Fig. 13. Fig. 13 is a schematic cross-sectional view of the electronic control device according to the fourth embodiment, seen from the same direction as the VV arrow shown in Fig. 3.

The main difference between the electronic control device 1E according to the fourth embodiment shown in FIG. 13 and the third embodiment is that the portion of the base portion 34E of the heat dissipation member 31E that comes into contact with the conductive member 5B is configured to be thicker than the other portions. The conductive member 5B according to this embodiment has the same structure as that of the third embodiment, and is positioned inside the multiple pedestal portions 35 of the heat dissipation member 31 and outside the multiple heat dissipation fins 36 when viewed from the orthogonal direction of the printed wiring board 11. The rest of the structure of the electronic control device 1E according to the fourth embodiment is the same as the structure of the electronic control device 1B according to the third embodiment, and a description thereof will be omitted.

Specifically, the base portion 34E of the heat dissipation member 31E is composed of a base body 34E1 supported by multiple pedestal portions 35 in the same position as in the third embodiment, and a reinforcing rib 34E2 that protrudes from the surface of the base body 34E1 on the heat dissipation fin 36 side toward the opposing wall 24 of the housing 3B. The reinforcing rib 34E2 is the portion that comes into contact with the annular conductive member 5B, and is an annular protrusion that is located inside the multiple pedestal portions 35 when viewed from the orthogonal direction of the printed wiring board 11. In other words, the portion of the base portion 34E that is pressed by the opposing wall 24 of the housing 3B via the conductive member 5B is made thicker by the reinforcing rib 34E2.

In this embodiment, the portion of the base portion 34E of the heat dissipation member 31E where the annular conductive member 5B is arranged is configured to be thicker than the other portions by the amount of the reinforcing rib 34E2. This reinforcing rib 34E2 improves the rigidity of the base portion 34E. Therefore, deformation of the base portion 34E that is pressed by the opposing wall 24 of the housing 3B via the conductive member 5B is suppressed by the improved rigidity provided by the reinforcing rib 34E2.

According to the fourth embodiment described above, similar to the first embodiment, by interposing a conductive member 5B between the heat dissipation member 31E and the housing 3B and blocking the heat dissipation opening 28B (opening) of the housing 3B together with the heat dissipation member 31E, it is possible to suppress the leakage of electromagnetic noise to the outside of the housing and the intrusion into the inside of the housing. Furthermore, since the conductive member 5B interposed between the heat dissipation member 31E and the housing 3B has thermal conductivity, it is possible to ensure a heat dissipation path from the electronic component 12 to the heat dissipation member 31E as well as a heat dissipation path to the housing 3B via the conductive member 5B. Therefore, it is possible to improve both electromagnetic compatibility and heat dissipation.

[Other embodiments]
The present invention is not limited to the above-described embodiment, and includes various modified examples. The above-described embodiment has been described in detail to easily explain the present invention, and is not necessarily limited to those having all of the configurations described. It is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

For example, in the above-described embodiment, an example has been shown in which the electronic control device 1 is mounted on a vehicle. However, the electronic control device can also be configured to be mounted on something other than a vehicle, so long as it is an electronic control device that is affected by heat generated by electronic components and electromagnetic noise. For example, it can also be applied to electronic control devices for unmanned aerial vehicles (drones) and the like.

In the above-mentioned embodiment, examples have been shown in which the conductive member 5 is made of a spreadable adhesive or CIPG. However, the conductive member can also be made of a sealing material such as an elastic body, as long as it has electrical conductivity and thermal conductivity.

In addition, in the first modified example of the third embodiment described above, an example of a configuration in which the annular conductive member 5C is positioned inside the multiple pedestal portions 35 of the heat dissipation member 31 when viewed from a direction perpendicular to the printed wiring board 11 is shown. However, the annular conductive member can also be configured to be positioned outside the multiple pedestal portions 35 of the heat dissipation member 31, as in the second embodiment. Even in this case, if the conductive member is formed into a ring shape by coating, the thickness of the conductive member can be kept constant by maintaining the coating speed constant.

1, 1A, 1B, 1C, 1D, 1E...Electronic control device, 2...Circuit board, 3, 3A, 3B...Housing, 5, 5A, 5B, 5C, 5D...Conductive member, 11...Printed wiring board (wiring board), 12...Electronic component, 28, 28A, 28B...Heat dissipation opening (opening), 31, 31A, 31E...Heat dissipation member, 32...Heat conductive member, 34, 34A, 34E...Base portion, 35...Pedestal portion, 36...Heat dissipation fins

Claims

a circuit board having a wiring board on which a wiring pattern is formed and electronic components mounted on the wiring board;
a heat dissipation member made of metal and thermally connected to the electronic component via a thermal conductive member;
a metal housing that houses the circuit board and has an opening in which the heat dissipation member is disposed so that a portion of the heat dissipation member is exposed to the outside;
a conductive member interposed between the heat dissipation member and the housing and closing the opening of the housing together with the heat dissipation member;
The electronic control device, wherein the conductive member is a member having thermal conductivity.
2. The electronic control device according to claim 1,
The heat dissipation member is
a base portion in direct contact with the heat conductive member;
a plurality of pedestals provided on the electronic component side of the base portion and fixed onto the wiring board to support the base portion;
a heat dissipation fin provided on the base portion on a side of the opening and exposed to an outside of the housing through the opening,
the conductive member is arranged so as to be sandwiched between the base portion of the heat dissipation member and the housing, and is arranged in a position that does not overlap with the multiple pedestal portions of the heat dissipation member when viewed from a direction perpendicular to the wiring board.
3. The electronic control device according to claim 2,
the conductive member is disposed at a position outside the plurality of pedestals when viewed in a direction perpendicular to the wiring board.
3. The electronic control device according to claim 2,
the conductive member is disposed at a position inside the plurality of pedestal portions of the heat dissipation member when viewed in a direction perpendicular to the wiring board.
5. The electronic control device according to claim 4,
The electronic control device according to claim 1, wherein the conductive member is disposed along an outer periphery of the electronic component when viewed from a direction perpendicular to the wiring board.
3. The electronic control device according to claim 2,
The electronic control device, wherein the conductive member is formed in a circular ring shape.
5. The electronic control device according to claim 4,
the conductive member is arranged along an outer peripheral edge of the base portion while avoiding the positions of the multiple pedestal portions of the heat dissipation member when viewed from a direction perpendicular to the wiring board.
5. The electronic control device according to claim 4,
The electronic control device, wherein the base portion of the heat dissipation member is configured so that a portion where the conductive member is disposed is thicker than other portions.
2. The electronic control device according to claim 1,
The electronic control device, wherein the conductive member is made of CIPG formed by hardening a liquid gasket.
2. The electronic control device according to claim 1,
The electronic control device, wherein the conductive member is configured to contain a conductive filler that has been subjected to a metal plating process.
2. The electronic control device according to claim 1,
The electronic control device, wherein the conductive member is a member whose main material is resin.