JP2022054810A - Electronic control unit - Google Patents

Abstract

To effectively cool a circuit board by using water droplets that enter the inside of a casing.SOLUTION: An electronic control unit 1 mounted on a moving body includes a circuit board 15 on which electronic components 11 and 12 are mounted, a casing 3 that accommodates the circuit board 15, a plurality of communication holes 21 and 22 formed in the casing 3 and communicating the inside and the outside of the casing 3, and a plurality of communication passages 26 that pass through the inside of the casing 3 and are connected to the communication holes 21 and 22 at both ends. The communication passage 26 is formed at least in part through the projection plane of the circuit board 15. Further, the communication passage 26 is formed at least in part through the projection planes of the heat-generating electronic components 11 and 12 formed on the circuit board 15.SELECTED DRAWING: Figure 2

Description

The technology disclosed in this specification relates to an electronic control unit for controlling electrical components mounted on a vehicle such as an automobile.

Conventionally, as this kind of technology, for example, the "electronic control unit" described in Patent Document 1 below is known. This unit is made of a circuit board on which electronic components are mounted, a metal casing that houses the circuit board, a metal lid member that closes the top opening of the casing, and a resin that is placed in the side opening of the casing. The casing, the lid member, and the connector portion are each connected via a sealing material. An unsealed portion without a sealing material is provided at the joint portion between the connector portion and the casing, and a communication passage for communicating the inside and outside of the casing is formed in this unsealed portion. Further, the casing is provided with a waterproof wall that separates the unsealed portion and the substrate accommodating portion in which the circuit board is accommodated. This waterproof wall blocks water droplets that have entered the inside of the casing through the continuous passage from flowing to the substrate accommodating portion. Further, a plurality of heat radiation fins for cooling are formed on the outer wall portion of the casing.

Japanese Unexamined Patent Publication No. 2019-41559

However, in the electronic control unit described in Patent Document 1, although water droplets that have entered the inside of the casing through the communication passage can be cooled in the vicinity of the connector portion by passing through the communication passage, the circuit board, in particular, is used. Did not cool the heat-generating electronic components on the circuit board, and could not effectively cool the circuit board by utilizing the water droplets entering the inside of the casing.

This disclosure technique has been made in view of the above circumstances, and an object thereof is to provide an electronic control unit capable of effectively cooling a circuit board by utilizing water droplets invading the inside of a casing. To do.

In order to achieve the above object, the technique according to claim 1 is a circuit board on which electronic components are mounted, a casing that houses the circuit board, and a plurality of communication formed in the casing and communicating the inside and the outside of the casing. In an electronic control unit mounted on a moving body, which comprises a hole and a plurality of communication passages that pass through the inside of a casing and are connected to communication holes at both ends, the communication passage is at least partially in the projection plane of a circuit board. The purpose is to be formed through.

According to the configuration of the above technique, water droplets that have entered the inside of the casing from the communication hole move in the projection plane of the circuit board, that is, in the vicinity of the circuit board through the communication passage. These water droplets take heat away from the vicinity of the circuit board and evaporate.

In order to achieve the above object, the technique according to claim 2 is the technique according to claim 1. In the technique according to claim 1, the communication passage is formed in the projection plane of a heat-generating electronic component, which is at least partially formed on a circuit board. The purpose is to be formed through.

According to the configuration of the above technique, in addition to the operation of the technique according to claim 1, water droplets that have entered the inside of the casing through the communication hole generate heat on the circuit board through the communication path in the projection plane of the electronic component. That is, it moves in the vicinity of the electronic component that generates heat. These water droplets take heat away from the vicinity of the electronic component and evaporate.

In order to achieve the above object, the technique according to claim 3 further includes, in the technique according to claim 1 or 2, a contact portion that protrudes toward the circuit board inside the casing and comes into contact with the circuit board. , At least one communication passage is intended to penetrate the contact portion.

According to the configuration of the above technique, in addition to the operation of the technique according to claim 1 or 2, the water droplets that have entered the inside of the casing from the communication hole penetrate the circuit through the contact portion in contact with the circuit board. It will move near the board. The water droplets take heat away from the vicinity of the circuit board above the contact and evaporate.

In order to achieve the above object, the technique according to claim 4 is the technique according to any one of claims 1 to 3, wherein at least one communication passage is from a communication hole at one end to a communication hole at the other end. The purpose is to incline toward it.

According to the configuration of the above technique, in addition to the operation of the technique according to any one of claims 1 to 3, water droplets that have entered the inside of the casing from the communication hole at one end enter the communication hole at the other end along the inclination of the communication path. It becomes easy to flow to.

In order to achieve the above object, the technique according to claim 5 is the technique according to any one of claims 1 to 3, wherein at least one communication passage is from the communication holes at both ends to the lowest point in the center. The purpose is to incline toward the bottom and form a communication hole at the lowest point.

According to the configuration of the above technique, in addition to the operation of the technique according to any one of claims 1 to 3, water droplets that have entered the inside of the casing through the communication holes at both ends communicate with the lowest point along the inclination of the communication passage. It becomes easier to flow into the hole.

In order to achieve the above object, the technique according to claim 6 is the electronic control unit according to any one of claims 1 to 5, wherein a plurality of heat radiation fins are formed on the outer wall of the casing, and the communication passage is formed. It is intended that at least a part thereof is formed through the projection plane of the region containing a plurality of heat radiation fins.

According to the configuration of the above technique, in addition to the operation of the technique according to any one of claims 1 to 5, water droplets that have entered the inside of the casing through the communication hole project a region containing the heat radiation fin through the communication passage. It will move in the plane, that is, in the vicinity of the heat dissipation fins. These water droplets take heat away from the heat radiation fins and evaporate.

According to the technique according to claim 1, the circuit board can be effectively cooled by utilizing the water droplets entering the inside of the casing.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, it is possible to effectively cool the heat-generating electronic components on the circuit board by utilizing the water droplets that invade the inside of the casing. can.

According to the technique of claim 3, in addition to the effect of the technique of claim 1 or 2, it is possible to effectively cool the circuit board on the contact portion by utilizing the water droplets penetrating the inside of the casing. can.

According to the fourth aspect of the present invention, in addition to the effect of the technique according to any one of claims 1 to 3, water droplets that have entered the inside of the casing through the communication hole at one end are discharged from the communication hole at the other end to the outside of the casing. It can be easily discharged to the casing, and water droplets can be prevented from accumulating inside the casing.

According to the technique according to claim 5, in addition to the effect of the technique according to any one of claims 1 to 3, water droplets that have entered the inside of the casing through the communication holes at both ends of the casing can be removed from the communication holes at the lowest point. It can be easily discharged to the outside, and water droplets can be prevented from accumulating inside the casing.

According to the technique according to claim 6, in addition to the effect of the technique according to any one of claims 1 to 5, the heat radiating fin can be effectively cooled by utilizing the water droplets entering the inside of the casing. , The heat dissipation of the casing can be improved.

The perspective view which shows the electronic control unit which concerns on 1st Embodiment. An exploded perspective view showing an electronic control unit according to the first embodiment. FIG. 1 is a sectional view taken along line AA of FIG. 1 showing an electronic control unit according to the first embodiment. The plan view which shows the casing which concerns on 1st Embodiment. FIG. 4 is a sectional view taken along line BB of FIG. 4 showing a casing according to the first embodiment. FIG. 4 is a sectional view taken along line CC of FIG. 4 showing a casing according to the first embodiment. The plan view which shows the casing which concerns on 2nd Embodiment. FIG. 7 is a sectional view taken along line DD of FIG. 7 showing a casing according to a second embodiment. FIG. 6 is a cross-sectional view according to FIG. 6 showing a casing according to a third embodiment. FIG. 6 is a cross-sectional view according to FIG. 6 showing a casing according to a fourth embodiment.

Hereinafter, some embodiments embodying the electronic control unit will be described in detail with reference to the drawings.

<First Embodiment>
The electronic control unit of the first embodiment will be described. The electronic control unit of this embodiment is used, for example, as a fuel pump controller (FPC) for controlling a fuel pump mounted on an automobile.

[Overall configuration of electronic control unit]
FIG. 1 shows the electronic control unit 1 of this embodiment by a perspective view. FIG. 2 also shows the electronic control unit 1 in an exploded perspective view. FIG. 3 also shows the electronic control unit 1 with a cross-sectional view taken along the line AA of FIG. As shown in FIGS. 1 to 3, the electronic control unit 1 of this embodiment includes a circuit board 15 on which electronic components 11 and 12 are mounted, a casing 3 that houses the circuit board 15, and an upper surface opening 3a of the casing 3. It is provided with a lid member 4 for closing the lid member 4. The electronic control unit 1 also includes a connector portion including wiring to and from the circuit board 15, a seal member for sealing between the casing 3 and the lid member 4, and a member such as a clip for fixing the lid member 4 to the casing 3. However, their illustrations are omitted for convenience.

In the electronic control unit 1, the circuit board 15 is housed in the casing 3, and the connector portion is provided between the casing 3 and the lid member 4. The lid member 4 is coupled to the casing 3 via a sealing material and fixed to the casing 3 by a clip. The electronic control unit 1 configured in this way is attached to a vehicle (body) and is electrically connected to a fuel pump (not shown) via a connector portion by a wire harness (not shown). The upper and lower parts of the electronic control unit 1 in FIGS. 1 to 3 indicate the arrangement state in which the unit 1 is attached to the vehicle.

[Circuit board configuration]
The circuit board 15 constitutes a control circuit for controlling the fuel pump. Electronic components 11, 12 and the like such as ICs, transistors, coils and capacitors are mounted on the circuit board 15. Here, the square electronic component 11 in the plan view shown in FIGS. 2 and 3 corresponds to an IC and can generate heat at a high temperature.

[Casing configuration]
FIG. 4 shows the casing 3 in a plan view. FIG. 5 shows the casing 3 with a cross-sectional view taken along the line BB of FIG. FIG. 6 shows the casing 3 with a cross-sectional view taken along the line CC of FIG. The casing 3 has a substantially rectangular parallelepiped shape made of metal (for example, made of aluminum in this embodiment), and has a pair of long side walls 3b extending in the longitudinal direction in a plan view, a pair of short side walls 3c extending in the lateral direction, and a bottom. It includes a wall 3d, a substrate accommodating portion 3e surrounded by the long side wall 3b, the short side wall 3c, and the bottom wall 3d, and an upper surface opening 3a. A plurality of heat exchange fins 5 extending in the longitudinal direction are formed on the outer wall of the casing 3, that is, the lower surface of the bottom wall 3d. The board accommodating portion 3e is a space for accommodating the circuit board 15. The upper surface opening 3a opens over the entire upper surface of the casing 3 and is closed by the lid member 4. In order to support the circuit board 15, the board accommodating portion 3e is provided with a trapezoidal contact portion 6 that projects upward from the bottom wall 3d toward the circuit board 15 and contacts the circuit board 15. As shown in FIG. 3, a part of the circuit board 15 is adhered and fixed on the contact portion 6 via the thermal paste 17.

As shown in FIGS. 1 to 6, the casing 3 is formed with a plurality of communication holes 21 and 22 that communicate the inside and the outside of the casing 3. In this embodiment, the communication holes 21 and 22 are formed so as to be lined up along the bottom wall 3d at the short side walls 3c facing each other. Further, the casing 3 is formed with a plurality of communication passages 26 that pass through the inside thereof and are connected to the communication holes 21 and 22 at both ends. In this embodiment, these communication passages 26 are formed in parallel on the bottom wall 3d of the casing 3 so as to extend in the longitudinal direction, and are formed in a groove shape. In this embodiment, as shown in FIG. 6, the upper end surface 3f of the casing 3 is arranged horizontally, and the bottom wall 3d and the plurality of communication passages 26 are formed so as to be parallel to the upper end surface 3f. In this embodiment, in the arrangement state shown in FIG. 6, the plurality of communication passages 26 extend in the horizontal direction.

In this embodiment, as shown in FIG. 4, all of these communication passages 26 are formed so as to pass through the projection plane of the circuit board 15. Further, a part of these communication passages 26 is formed through the projection planes of the heat-generating electronic components 11 and 12 formed on the circuit board 15. Further, a part of the plurality of communication passages 26 is provided so as to penetrate the contact portion 6. The electronic component 11 that generates heat at a high temperature is arranged in the projection plane of the contact portion 6. In addition, the entire communication passage 26 is formed through the projection plane of the region containing the plurality of heat radiation fins 5. Each communication passage 26 is arranged between two heat radiation fins 5 adjacent to each other in a plan view.

[Action and effect of electronic control unit]
As described above, according to the configuration of the electronic control unit 1 of this embodiment, since a plurality of communication holes 21 and 22 are provided in the short side wall 3c of the casing 3, the casing 3 is provided through the communication holes 21 and 22. The pressure inside the casing can be adjusted. Specifically, the pressure inside the casing 3 can be maintained at the same level as the atmospheric pressure, and it is possible to prevent the inside from becoming a negative pressure.

Here, water droplets may enter the inside of the casing 3 through the plurality of communication holes 21 and 22. In this embodiment, a plurality of communication passages 26 are formed at the bottom wall 3d of the casing 3 through the projection plane of the circuit board 15, and both ends of each communication passage 26 are connected to the communication holes 21 and 22. Ru. Therefore, the water droplets that have entered the inside of the casing 3 from the communication holes 21 and 22 move in the projection plane of the circuit board 15 through the communication passage 26, that is, in the vicinity of the circuit board 15. For example, when the electronic control unit 1 vibrates with the vibration of the vehicle, the water droplets entering the communication passage 26 move below the circuit board 15 along the communication passage 26. The water droplets take heat from the inside of the casing 3 and evaporate. Therefore, the circuit board 15 can be effectively cooled by utilizing the water droplets that invade the inside of the casing 3. Moreover, the water droplets that have entered the inside of the casing 3 can be discharged to the outside of the casing 3 without coming into contact with the circuit board 15 and the electronic components 11 and 12.

Moreover, according to the configuration of this embodiment, water droplets that have entered the inside of the casing 3 from the communication holes 21 and 22 are generated in the projection planes of the electronic components 11 and 12 on the circuit board 15 via the communication passage 26. That is, it moves in the vicinity of the electronic components 11 and 12 that generate heat. These water droplets take heat in the vicinity of the electronic components 11 and 12 and evaporate. Therefore, it is possible to effectively cool the heat-generating electronic components 11 and 12 on the circuit board 15 by utilizing the water droplets that invade the inside of the casing 3.

Further, according to the configuration of this embodiment, water droplets that have entered the inside of the casing 3 from the communication holes 21 and 22 pass through the contact portion 6 that contacts the circuit board 15 and are in the vicinity of the circuit board 15 via the communication passage 26. Will be moved. The water droplets take heat away from the vicinity of the circuit board 15 on the contact portion 6 and evaporate. Therefore, the circuit board 15 above the contact portion 6, particularly the electronic component 11 that generates heat at a high temperature, can be effectively cooled by utilizing the water droplets that invade the inside of the casing 3.

Further, according to the configuration of this embodiment, a plurality of heat radiation fins 5 are formed on the outer wall of the casing 3, that is, the lower surface of the bottom wall 3d. Then, a plurality of communication passages 26 are formed through the projection plane of the region including the heat radiation fins 5. Therefore, the water droplets that have entered the inside of the casing 3 from the communication holes 21 and 22 move through the communication passage 26 in the projection plane of the region including the heat radiation fins 5, that is, in the vicinity of the heat radiation fins 5. The water droplets take heat in the vicinity of the heat radiation fins 5 and evaporate. Therefore, the heat radiating fin 5 can be effectively cooled by utilizing the water droplets entering the inside of the casing 3, and the heat radiating property of the casing 3 can be improved.

<Second Embodiment>
The electronic control unit of the second embodiment will be described. In each of the embodiments described below, the same components as those in the first embodiment are designated by the same reference numerals and description thereof will be omitted, and the differences will be mainly described below.

[Casing configuration]
This embodiment differs from the first embodiment in the configuration of the casing 3, particularly the configuration relating to the contact portion 6. FIG. 7 shows the casing 3 of this embodiment in a plan view. FIG. 8 shows the casing 3 of this embodiment by a cross-sectional view taken along the line DD of FIG. In this embodiment, in the portion where the communication passage 26 penetrates the contact portion 6, the communication passage 26 is continuous to the upper surface of the contact portion 6 and is open on the upper surface thereof.

Therefore, according to the configuration of this embodiment, in addition to the operation and effect of the above-described embodiment, the circuit board 15 that comes into contact with the contact portion 6 by the water droplets moving in the communication passage 26 at the contact portion 6 is provided with the thermal paste 17. Can be cooled directly through.

<Third Embodiment>
The electronic control unit of the third embodiment will be described.

[Casing configuration]
This embodiment differs from each of the above-described embodiments in the configuration of the casing 3, particularly the configuration relating to the communication passage 26. FIG. 9 shows the casing 3 of this embodiment by a cross-sectional view according to FIG. In this embodiment, in the arrangement state in which the electronic control unit 1 is attached to the vehicle, as shown in FIG. 9, all the communication passages 26 are horizontal from the communication hole 21 at one end to the communication hole 22 at the other end. It is formed so as to incline with respect to the direction.

Therefore, according to the configuration of this embodiment, in addition to the operation and effect of the embodiment, the water droplet that has entered the inside of the casing 3 from the communication hole 21 at one end enters the communication hole at the other end along the inclination of the communication passage 26. It becomes easy to flow to 22. Therefore, it is possible to easily discharge the water droplets that have entered the inside of the casing 3 from the communication hole 21 at one end to the outside of the casing 3 from the communication hole 22 at the other end, and it is possible to prevent the water droplets from accumulating inside the casing 3. can.

<Fourth Embodiment>
The electronic control unit of the fourth embodiment will be described.

[Casing configuration]
This embodiment differs from each of the above-described embodiments in the configuration of the casing 3, particularly the configuration relating to the communication passage 26. FIG. 10 shows the casing 3 of this embodiment by a cross-sectional view according to FIG. In this embodiment, in the arrangement state in which the electronic control unit 1 is attached to the vehicle, as shown in FIG. 10, all the communication passages 26 are directed from the communication holes 21 and 22 at both ends toward the lowest point in the center. It is formed so as to be inclined, and a communication hole 23 is formed at the lowest point.

Therefore, according to the configuration of this embodiment, in addition to the operation and effect of the embodiment, water droplets that have entered the inside of the casing 3 from the communication holes 21 and 22 at both ends reach the lowest point along the inclination of the communication passage 26. It becomes easy to flow to the communication hole 23. Therefore, it is possible to easily discharge the water droplets that have entered the inside of the casing 3 from the communication holes 21 and 22 at both ends to the outside of the casing 3 from the communication holes 23 at the lowest point, and it is difficult for the water droplets to collect inside the casing 3. can do.

It should be noted that this disclosure technique is not limited to each of the above-described embodiments, and a part of the configuration may be appropriately modified and implemented within a range that does not deviate from the purpose of the disclosure technique.

(1) In the third and fourth embodiments, all the communication passages 26 are formed to be inclined, but some of the communication passages may be formed to be inclined.

(2) In each of the above-described embodiments, the number, size, and depth of the communication passages 26 are examples, and can be appropriately changed.

This disclosed technology can be applied to an electronic control unit for controlling electrical components mounted on a vehicle such as an automobile.

1 Electronic control unit 3 Casing 4 Cover member 5 Radiation fin 6 Contact part 11 Electronic component 12 Electronic component 15 Circuit board 21 Communication hole 22 Communication hole 23 Communication hole 26 Communication passage

Claims (6)

A circuit board on which electronic components are mounted and
The casing that houses the circuit board and
A plurality of communication holes formed in the casing and communicating the inside and the outside of the casing,
In an electronic control unit mounted on a moving body, the electronic control unit includes a plurality of communication passages that pass through the inside of the casing and are connected to the communication holes at both ends.
The electronic control unit is characterized in that at least a part of the communication passage is formed through the projection plane of the circuit board. In the electronic control unit according to claim 1,
The electronic control unit is characterized in that the communication passage is formed at least in part through the projection plane of the electronic component that generates heat and is formed on the circuit board. In the electronic control unit according to claim 1 or 2.
Further, a contact portion is further provided inside the casing so as to project toward the circuit board and come into contact with the circuit board.
An electronic control unit characterized in that at least one of the communication passages penetrates the contact portion. In the electronic control unit according to any one of claims 1 to 3.
An electronic control unit characterized in that at least one of the communication passages is inclined from the communication hole at one end toward the communication hole at the other end. In the electronic control unit according to any one of claims 1 to 3.
An electronic control unit characterized in that at least one communication passage is inclined from the communication holes at both ends toward a central lowest point, and the communication hole is formed at the lowest point. In the electronic control unit according to any one of claims 1 to 5.
A plurality of heat radiation fins are formed on the outer wall of the casing.
An electronic control unit characterized in that at least a part of the communication passage is formed through a projection plane of a region including a plurality of the heat radiation fins.

Images