Electronic Control Unit

Abstract

To provide an electronic controller that suppresses a rise in atmospheric temperature inside an enclosure.SOLUTION: An electronic controller comprises an electronic component which generates heat, a substrate mounted with the electronic component, a heat conductive member having heat conductivity, an enclosure housing the electronic component, substrate and heat conductive member, and a bracket for attaching the enclosure to an attached body. The enclosure has an attachment wall part of an outer wall where the bracket is attached. The electronic component is mounted on a surface of the substrate on the side facing the attachment wall part. The heat conductive member connects the electronic component and the attachment wall part to each other. A first contact part in contact with the attachment wall part of the bracket and a second contact part in contact with the attachment wall part of the heat conductive member are arranged at positions facing each other across the attachment wall part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electronic control device. [Background technology]

[0002] An electronic control device is known that houses a circuit board on which a heat-generating element is mounted and that includes a housing that is attached to a side wall of a vehicle's engine compartment by a bracket, and the mounting portion of the housing to which the bracket is attached protrudes toward the inside of the housing at a position corresponding to the heat-generating element (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-201283 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the electronic control device of Patent Document 1, the mounting portion is thickened and a screw hole is provided for the screw that fixes the bracket, which increases the thermal capacity of the thick mounting portion and makes the housing more likely to retain heat. As a result, the housing heats up and the atmospheric temperature inside the housing rises, which may affect the electronic components inside the housing.

[0005] An object of the present invention is to provide an electronic control device that suppresses an increase in the atmospheric temperature inside a housing. [Means for solving the problem]

[0006] The present invention solves the above problem by providing an electronic control device comprising a heat-generating electronic component, a board on which the electronic component is mounted, a thermally conductive member, a housing that houses the electronic component, the board, and the thermally conductive member, and a bracket for attaching the housing to a support body, wherein the housing has a mounting wall portion of its outer wall to which the bracket is attached, the electronic component is mounted on the surface of the board facing the mounting wall portion, and the thermally conductive member connects between the electronic component and the mounting wall portion, and a first contact portion in contact with the mounting wall portion of the bracket and a second contact portion in contact with the mounting wall portion of the thermally conductive member are positioned opposite each other via the mounting wall portion. Effect of the Invention

[0007] According to the present invention, it is possible to suppress an increase in the ambient temperature inside the housing of the electronic control device. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of an electronic control device according to the present embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the electronic control device taken along line X1-X1 in FIG. [Diagram 3] FIG. 3 is a plan view of an electronic control device having a general heat dissipation structure and a cross-sectional view of the electronic control device taken along line X2-X2 in the plan view. [Figure 4] FIG. 4 is a plan view of an electronic control device according to a first modified example of the present embodiment, and a cross-sectional view of the electronic control device taken along line X3-X3 in the plan view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an electronic control device to which the heat dissipation structure according to the present embodiment is applied will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of the electronic control device according to the present embodiment. In FIG. 1, the short side direction of the plane of the mounting wall portion 13 is the direction X, the long side direction of the plane of the mounting wall portion 13 is the direction Y, and the thickness direction of the mounting wall portion 13 is the direction Z. In this embodiment, as shown in FIG. 1, the electronic control device 1 includes a housing 10, a bracket 20 for mounting the housing 10 to a mounting body 2, and a connector 30. The electronic control device 1 according to the present embodiment is applied to, for example, an ECU of a vehicle. The mounting body 2 is a side wall of a vehicle body or the like. The mounting body 2 is configured as a metal body, so that the heat dissipation efficiency is high. The electronic control device 1 is fixed to the mounting body 2 via the bracket 20. The housing 10 accommodates a circuit board 40 and a heat conductive member 50. The circuit board 40 includes a board 41 and an electronic component 42 including a heat generating element 43. The heat conducting member 50 connects the heating element 43 and the mounting wall portion 13 of the housing 10 .

[0010] FIG. 2 is a cross-sectional view of the electronic control device 1 taken along line X1-X1 in FIG. 1. Arrow A in FIG. 2 shows a schematic heat conduction path of heat generated by the heat generating element 43. In FIG. 2, the longitudinal direction of the plane of the mounting wall 13 is defined as direction Y, and the thickness direction of the mounting wall 13 is defined as direction Z. The housing 10 is formed in a rectangular parallelepiped shape. The housing 10 is, for example, a case made of metal such as aluminum. The housing 10 may also be a case made of synthetic resin. The housing 10 is composed of a box-shaped case 11 with one side open, and a cover 12 having a substantially rectangular plate shape that closes the open side of the case 11. The case 11 and the cover 12 are fastened together by, for example, screws. As a result, the housing 10 has an internal space that accommodates the circuit board 40 and the heat conductive member 50. The housing 10 may be composed of an integrated case, not limited to separate members such as the case 11 and the cover 12.

[0011] The housing 10 has an attachment wall 13 to which a bracket 20 is attached among the outer walls. The housing 10 has side walls 10a that surround an object such as a circuit board 40 from all sides, a top wall 10b that serves as the ceiling surface of the object, and a bottom wall 10c that serves as the bottom surface of the object. The attachment wall 13 corresponds to the bottom wall 10c among the outer walls of the housing 10. The attachment wall 13 is attached to the object 2 via a bracket 20 so as to face the object 2. The bracket 20 is attached to the outer surface of the attachment wall 13, i.e., the attachment surface 13b that faces the object 2. In addition, a thermally conductive member 50, which will be described later, contacts the upper surface 13a of the attachment wall 13 opposite to the attachment surface 13b, i.e., the inner surface. The thickness of the attachment wall 13 of the housing 10 is thinner than the thickness of the walls other than the attachment wall 13 (corresponding to the side walls 10a and the top wall 10b). By reducing the thickness of the mounting wall 13, the heat conduction path from the heat conductive member 50 to the bracket 20 can be shortened. This prevents a wide area of ​​the housing 10 from becoming a heat conduction path, and prevents the ambient temperature inside the housing 10 from rising. In addition, by increasing the thickness of the outer walls of the housing 10 that do not become a heat conduction path (corresponding to the side wall 10a and the top wall 10b), the strength of the housing 10 can be increased. Note that, in order to prevent an effect on the heat conduction path, it is preferable that the mounting wall 13 has few irregularities and a uniform thickness.

[0012] The bracket 20 is disposed between the housing 10 and the mounting body 2, and mounts the housing 10 to the mounting body 2. The bracket 20 is attached to the mounting surface 13b of the mounting wall portion 13 by welding or bolt fastening. The bracket 20 is a heat conductive material. For example, the bracket 20 is formed by pressing a metal plate or the like. The bracket 20 transmits heat transmitted from the heating element 43 to the housing 10 to the mounting body 2. Since the mounting body 2 is configured as a metal body, the heat of the heating element 43 is dissipated to the mounting body through the bracket 20, so that the heat is not trapped in the housing 10 and the heat dissipation efficiency can be improved. The thermal conductivity of the bracket 20 is higher than that of the heat conductive member 50. The bracket 20 is made of a material having a higher thermal conductivity than the heat conductive member 50. For example, when the heat conductive member 50 is made of a resin material, the bracket 20 is made of a metal having a higher thermal conductivity than the resin material. This allows heat transferred from the thermally conductive member 50 to the housing 10 to be easily transferred to the bracket 20. The position of the contact portion of the bracket 20 that comes into contact with the mounting wall portion 13 will be described in detail later. In this embodiment, the contact portion of the bracket 20 that comes into contact with the mounting wall portion 13 corresponds to the contact surface 20a of the bracket. Furthermore, there may be one bracket 20 or multiple brackets 20. The housing 10 and the bracket 20 may be integrally molded using a thermally conductive metal or the like.

[0013] The connector 30 is a connector that serves as an external connection terminal mounted on the substrate 41, and is provided on the housing 10 so that one end is exposed to the outside of the housing 10.

[0014] The circuit board 40 includes a substrate 41 and an electronic component 42. The substrate 41 is a printed circuit board formed of known materials such as thermoplastic resin, thermosetting resin, ceramic, and a composite of glass and resin. The electronic component 42 is mounted on the substrate 41. The electronic component 42 is mounted on a mounting surface 41a of the substrate 41 facing the mounting wall 13 of the housing 10. That is, of the pair of main surfaces of the substrate 41, the surface located on the mounting wall 13 side becomes the mounting surface 41a of the electronic component 42, and the surface 41b located on the top wall 10b side becomes the surface opposite to the mounting surface 41a of the substrate 41. The electronic component 42 is a microcomputer, a transistor, a resistor, a capacitor, etc. In particular, the electronic component 42 includes a heat generating element 43, which is an electronic component that generates heat. The heat generating element 43 is a component that generates a large amount of heat, and is, for example, a power element such as an IGBT or a MOSFET, a high performance SoC, etc. The heat generated from the heat generating element 43 needs to be dissipated to the outside. In this embodiment, the heating element 43 is mounted on the center of the substrate 41. The heating element 43 is connected to the housing 10 via the thermal conductive member 50. Of the upper and lower surfaces (a pair of surfaces normal to the direction Y in FIG. 2), the upper surface 43a of the heating element 43 is in contact with the mounting surface 41a of the substrate 41, and the lower surface 43b is in contact with the thermal conductive member 50. Note that the connection between the heating element 43 and the housing 10 via the thermal conductive member 50 is a thermal connection, not an electrical connection. In this embodiment, the heating element 43 and the other electronic components 42 are mounted on the same mounting surface 41a of the substrate 41, but the electronic components 42 other than the heating element 43 may be mounted on the surface 41b opposite to the mounting surface 41a of the substrate 41.

[0015] The heat conducting member 50 is a heat conducting pad having thermal conductivity. The heat conducting member 50 is an elastic body such as silicone, and has flexibility that allows deformation. For example, the heat conducting member 50 is a thermoplastic material. By using an elastic body for the heat conducting member 50, it is possible to protect the circuit board 40 from heat while protecting the delicate circuit board 40 from shocks such as vibration. The heat conducting member 50 may be a resin material. The heat conducting member 50 may be a grease-like, gel-like, sheet-like material, or the like. The heat conducting member 50 is disposed between the heat generating element 43 and the mounting wall portion 13 of the housing 10 so as to be in contact with the heat generating element 43 and the mounting wall portion 13. The heat conducting member 50 connects between the heat generating element 43 and the mounting wall portion 13, and transfers heat generated by the heat generating element 43 to the mounting wall portion 13. The heat conducting member 50 is formed in a plate-like or rectangular parallelepiped shape, and of the upper and lower surfaces (a pair of surfaces normal to the direction Y in FIG. 2), the heat generating element 43 is fixed to the upper surface 50a of the heat conducting member 50, and the mounting wall portion 13 is fixed to the lower surface 50b. That is, the upper surface 50a of the heat conducting member 50 is in contact with the lower surface 43b of the heat generating element 43 so as to overlap with each other, and the lower surface 50b of the heat conducting member 50 is in contact with the upper surface 13a of the mounting wall portion 13 so as to overlap with each other. The length of the upper surface 50a of the heat conducting member 50 in the direction Y is not limited to be the same as the length of the lower surface 50b in the direction Y, and the length of the lower surface 50b in the direction Y may be longer than the length of the upper surface 50a in the direction Y. That is, the cross-sectional shape of the heat conducting member 50 may be a trapezoid. However, the area of ​​the lower surface 50b is smaller than the area of ​​the upper surface 13a of the mounting wall portion 13. By making the area of ​​the lower surface 50b smaller than the area of ​​the upper surface 13a of the mounting wall portion 13, the contact area of ​​the heat conduction member 50 with the mounting wall portion 13 can be reduced, and heat is prevented from being transferred from the heat conduction member 50 to a wide area of ​​the mounting wall portion 13. The heat conduction member 50 is not limited to contacting the upper surface 13a of the mounting wall portion 13 at a surface, but may contact at multiple points. The heat conduction member 50 and the heating element 43 are in contact such that the area of ​​the upper surface 50a of the heat conduction member 50 in contact with the heating element 43 matches the area of ​​the lower surface 43b of the heating element 43 in contact with the heat conduction member 50.

[0016] Next, the positional relationship between the contact surface 20a of the bracket 20 that contacts the mounting wall 13 and the lower surface 50b of the heat conductive member 50 that contacts the mounting wall 13 will be described. The contact surface 20a corresponds to the first contact portion in the claims, and the lower surface 50b corresponds to the second contact portion in the claims. The contact surface 20a of the bracket 20 and the lower surface 50b of the heat conductive member 50 are disposed at corresponding positions via the mounting wall 13. In this embodiment, the contact surface 20a of the bracket 20 and the lower surface 50b of the heat conductive member 50 are disposed at opposing positions via the mounting wall 13. That is, the contact surface 20a and the lower surface 50b are disposed on a straight line in the direction Z via the mounting wall 13. In this embodiment, the heat generating element 43 and the heat conductive member 50 are stacked so as to overlap in the direction Z, and the heat conductive member 50 and the bracket 20 are disposed at opposing positions via the mounting wall 13. That is, the heating element 43, the heat conducting member 50, the mounting wall 13 of the housing 10, and the bracket 20 are arranged in a straight line in the direction Z. As a result, the heat conducted from the heating element 43 to the mounting wall 13 is conducted to the mounting body 2 via the bracket 20, so that the range of the housing 10 that becomes the heat conduction path can be reduced, and the heat of the heating element 43 can be prevented from spreading to the mounting wall 13. In addition, the area of ​​the contact surface 20a is larger than the area of ​​the lower surface 50b. The lower surface 50b is located within a range that overlaps with the contact surface 20a in the direction Z. As a result, the heat conducted to the mounting wall 13 via the heat conducting member 50 is easily conducted to the bracket 20. In addition, in this embodiment, the contact surface 20a may be arranged adjacent to a position on the mounting surface 13b side corresponding to the position of the lower surface 50b, or may be arranged to surround a position on the mounting surface 13b side corresponding to the position of the lower surface 50b.

[0017] Here, a reference example of an electronic control device different from the present invention will be described. FIG. 3 is a plan view of an electronic control device having a general heat dissipation structure that dissipates heat from a housing, and a cross-sectional view of the electronic control device along the X2-X2 line in the plan view, which is a diagram for explaining a heat conduction path. The white arrows shown in FIG. 3 are schematic diagrams showing how heat generated by the heating element 43 is transferred. The heat conduction path from the heating element 43 to the attached body 2 and the path dissipated from the housing 10, which is the heat conduction path, to the inside and outside are shown. As shown in FIG. 3, when the heating element 43 generates heat, in order to prevent the heating element 43 from overheating, the heat is released from the heating element 43 to the housing 10, and the heat is dissipated from the housing 10 into the air, and the housing 10 is used as a heat conduction path to dissipate heat to the attached body 2 side. However, if a wide range of the housing 10 is used as a heat conduction path, the temperature of the housing 10 will increase and the atmospheric temperature inside the housing will rise. This may have a thermal effect on the electronic components 42 other than the heating element 43 in the housing 10. Also, since the temperature of the heating element 43 itself rises, it is necessary to limit the power consumption and suppress the processing capacity. Therefore, in this embodiment, the heat conduction path in the housing 10 is shortened and the range of the housing 10 where the temperature becomes high is reduced, thereby suppressing the rise in the atmospheric temperature inside the housing. This suppresses the temperature rise of the electronic components 42, improves the reliability of the circuit board 40, and improves the processing capacity by reducing the power consumption.

[0018] Next, a first modified example of the present invention will be described. FIG. 4 is a plan view of the electronic control device 1 according to the first modified example of the present invention, and a cross-sectional view of the electronic control device 1 taken along line X3-X3 in the plan view. Arrow A in FIG. 4 shows a schematic heat conduction path of heat generated by the heat generating element 43. In FIG. 4, the longitudinal direction of the plane of the mounting wall portion 13 is the direction Y, and the thickness direction of the mounting wall portion 13 is the direction Z. In the first modified example, the position of the bracket 20 attached to the mounting wall portion 13 and the shape of the heat conducting member 50 are different from those of the above-described embodiment of the present invention. The other configurations are the same as those of the above-described embodiment, and the description thereof is incorporated herein by reference. In the above-described embodiment, the heat generating element 43 and the bracket 20 are positioned in a straight line in the direction Z, but in the first modified example, the bracket 20 is positioned at a position deviated from the extension line of the heat generating element 43 in the direction Z. For example, the bracket 20 is attached to the peripheral portion of the mounting wall portion 13. The bracket 20 is positioned so that the peripheral edge of the bracket 20 coincides with the peripheral edge of the mounting wall portion 13.

[0019] In the first modification, the heat conducting member 50 is a member having an L-shaped cross section, and includes an upper surface 50a in contact with the heat generating element 43, a lower surface 50b in contact with the mounting wall 13, and a connection portion 53 connecting the upper surface 50a and the lower surface 50b. The heat conducting member 50 is, for example, a heat pipe or a vaper chamber. The connection portion 53 extends from the upper surface 50a to the peripheral side of the mounting wall 13 to which the bracket 20 is attached, bends in the direction Z at a position overlapping with the lower surface 50b in the direction Z, and connects to the lower surface 50b. The lower surface 50b contacts the housing 10 at a position facing the contact surface 20a via the mounting wall 13. As a result, the contact surface 20a and the lower surface 50b are arranged in a straight line in the direction Z, so that the heat conducted from the heat conducting member 50 to the mounting wall 13 can be prevented from being conducted to the mounting target 2 via the bracket 20 and spreading to the housing 10. The heat conducting member 50 may have a linear shape. In this case, the connection portion 53 connects the upper surface 50a and the lower surface 50b in a straight line. In addition, when the multiple brackets 20 are in contact with the mounting surface 13b of the housing 10, that is, when there are multiple contact surfaces 20a, the heat conducting member 50 may have a lower surface 50b disposed in a position facing each of the multiple contact surfaces 20a with the mounting wall portion 13 interposed therebetween.

[0020] As described above, in this embodiment, an electronic control device includes a heat-generating electronic component, a substrate on which the electronic component is mounted, a heat-conducting member having thermal conductivity, a housing that houses the electronic component, the substrate, and the heat-conducting member, and a bracket that attaches the housing to a mounting body, the housing has an outer wall that has a mounting wall to which the bracket is attached, the electronic component is mounted on the surface of the substrate facing the mounting wall, the heat-conducting member connects between the electronic component and the mounting wall, and a first contact portion that contacts the mounting wall portion of the bracket and a second contact portion that contacts the mounting wall portion of the heat-conducting member are disposed in opposing positions across the mounting wall. This makes it possible to suppress an increase in the ambient temperature inside the housing of the electronic control device.

[0021] In the present embodiment, the thickness of the mounting wall is thinner than the thickness of the remaining wall of the housing, thereby shortening the heat conduction path from the heat generating element to the mounting target.

[0022] In the present embodiment, the heat-conducting member is an elastic body, which makes it possible to protect the electronic components from the effects of heat and to suppress interference between the electronic components and the housing.

[0023] In this embodiment, the elastic body is a thermoplastic material, which provides a buffering force against external forces such as vibrations, thereby making it possible to suppress interference between the electronic component and the housing.

[0024] In the present embodiment, the thermal conductivity of the bracket is higher than that of the thermally conductive member, so that heat transferred from the thermally conductive member is more easily transferred to the bracket.

[0025] In this embodiment, the area of ​​the second contact portion is smaller than the area of ​​the first contact portion, which makes it easier for heat to be transferred from the thermally conductive member to the bracket.

[0026] The above-described embodiments are described for the purpose of facilitating understanding of the present invention, and are not described for the purpose of limiting the present invention. Therefore, the elements disclosed in the above embodiments are intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0027] 1...Electronic control device 10…Housing 13...Mounting wall 20…Bracket 30…Connector 40...Circuit board 41...Substrate 42...Electronic components 43...Heater element 50...Heat conductive material 2...Attached body

Claims

1. Heat-generating electronic components, A substrate on which the electronic components are mounted; A heat conductive member having thermal conductivity; a housing that houses the electronic components, the substrate, and the thermal conductive member; A bracket for attaching the housing to a mounting body, the housing has an attachment wall portion of an outer wall to which the bracket is attached, the electronic component is mounted on a surface of the board facing the mounting wall portion, the heat conductive member connects the electronic component and the mounting wall portion; a first contact portion of the bracket in contact with the mounting wall portion and a second contact portion of the heat conducting member in contact with the mounting wall portion are disposed at positions facing each other with the mounting wall portion interposed therebetween; The electronic control device, wherein the thermal conductivity of the bracket is higher than the thermal conductivity of the heat conducting member.

2. The electronic control device according to claim 1 , wherein the mounting wall portion has a thickness smaller than a thickness of a wall portion of the housing other than the mounting wall portion.

3. 3. The electronic control device according to claim 1, wherein the heat conductive member is an elastic body.

4. 4. The electronic control device according to claim 3, wherein the elastic body is a thermoplastic material.

5. 5. The electronic control device according to claim 1, wherein an area of ​​the second contact portion is smaller than an area of ​​the first contact portion.

6. A heat-generating electronic component; A substrate on which the electronic components are mounted; A heat conductive member having thermal conductivity; a housing that houses the electronic components, the substrate, and the thermal conductive member; A bracket for attaching the housing to a mounting body, the housing has an attachment wall portion of an outer wall to which the bracket is attached, the electronic component is mounted on a surface of the board facing the mounting wall portion, the heat conductive member connects the electronic component and the mounting wall portion; a first contact portion of the bracket in contact with the mounting wall portion and a second contact portion of the heat conducting member in contact with the mounting wall portion are disposed at positions facing each other with the mounting wall portion interposed therebetween; An electronic control device, wherein the mounting wall portion has a thickness smaller than a thickness of a wall portion of the housing other than the mounting wall portion.

Images