Electronic control device

Abstract

This electronic control device (10) is provided with: a substrate (21) configured to be attached to a metal housing (11) by means of a metal fixing member (22) and having a plurality of conductor layers (L1-L6) laminated with insulating layers (L7) therebetween; and a heat-generating element (23) configured to generate heat by energization. The plurality of conductor layers (L1-L6) include: first specific conductor layers (L1, L3, L5) having earth layers (E1-E3) configured to be electrically connected to the housing (11); and second specific conductor layers (L2, L4) having ground layers (G1, G3) configured to be electrically connected to the heat-generating elements (23). The earth layers (E1-E3) and the ground layers (G1, G3) are at least partially opposed to each other in the thickness direction of the substrate (21) with the insulating layers (L7) therebetween.

Description

Electronic control unit

[0001] The present disclosure relates to electronic control devices.

[0002] Conventionally, there are electronic control devices that are integrally attached to motors. The controller disclosed in Patent Document 1 has a circuit board on which electronic components are mounted. The circuit board is attached to a frame that functions as a heat sink and is provided at the axial end of the motor. The electronic components, including heat-generating components such as FETs, are mounted on the front surface of the circuit board. The back surface of the circuit board is in contact with the frame.

[0003] The board has thermal vias that penetrate the board in the thickness direction directly below the heat-generating components. Heat generated by the heat-generating components is transferred from the front surface to the back surface of the board via the thermal vias. The heat transferred to the back surface of the board is dissipated to the outside via the frame.

[0004] JP 2019-80471 A

[0005] In recent years, electronic control devices have become smaller while at the same time being required to have higher performance. This has led to a trend toward higher mounting densities of electronic components on circuit boards. This has raised concerns about temperature increases due to increased heat generation from the circuit boards. Therefore, there is a need to improve the heat dissipation capabilities of circuit boards.

[0006] According to one aspect of the present disclosure, an electronic control device includes a substrate configured to be attached to a metal housing by a metal fixing member, the substrate having multiple conductor layers stacked with an insulating layer interposed therebetween, and a heat-generating element configured to generate heat when energized. The multiple conductor layers include a first specific conductor layer having an earth layer configured to be electrically connected to the housing, and a second specific conductor layer having a ground layer configured to be electrically connected to the heat-generating element. The earth layer and the ground layer are at least partially opposed to each other in a thickness direction of the substrate via the insulating layer.

[0007] 1 is a cross-sectional view showing an attachment state of an electronic control device according to an embodiment to a controlled object. FIG. 2 is a cross-sectional view of the electronic control device of FIG. 1 and its periphery. FIG. 3 is a cross-sectional view of a first conductor layer in the electronic control device of FIG. 2. FIG. 4 is a cross-sectional view of a second conductor layer in the electronic control device of FIG. 2. FIG. 5 is a cross-sectional view of a third conductor layer in the electronic control device of FIG. 2. FIG. 6 is a cross-sectional view of a fourth conductor layer in the electronic control device of FIG. 2. FIG. 7 is a cross-sectional view of a fifth conductor layer in the electronic control device of FIG. 2. FIG. 8 is a cross-sectional view of a sixth conductor layer in the electronic control device of FIG. 2. FIG. 9 is a plan view of the first conductor layer of FIG. 3, showing the boundary between the first earth layer and the first wiring layer. FIG. 10 is a cross-sectional view of the second conductor layer of FIG. 4, in which the first earth layer is projected onto the first ground layer.

[0008] An electronic control device according to one embodiment will be described. The electronic control device is, for example, for a vehicle. As shown in FIG. 1 , the electronic control device 10 is provided in a housing 11 of a controlled object. The controlled object is, for example, a motor. The housing 11 is a case for the motor, and is, for example, a cylindrical body with a circular cross-sectional shape. An end of the housing 11 is open in the axial direction. The open end is the end of the housing 11 on which the electronic control device 10 is mounted. The opening of the housing 11 is closed by fitting a lid 12. The housing 11 and the lid 12 are each made of metal. The metal is, for example, iron or an aluminum alloy.

[0009] The end of the housing 11 has a substrate accommodating portion 13. The substrate accommodating portion 13 is located axially outward relative to the cover 12. The substrate accommodating portion 13 is a portion of the end of the housing 11 where the inner diameter is enlarged. The substrate accommodating portion 13 has an attachment portion 13A. The attachment portion 13A has a flat surface that extends in the radial direction of the housing 11. The flat surface is an attachment surface for the substrate 21.

[0010] The electronic control device 10 has a substrate 21. The substrate 21 is accommodated inside the substrate accommodation portion 13. The substrate 21 is in contact with the mounting portion 13A. The substrate 21 is flat. One or more through holes 21A are provided on the periphery of the substrate 21. The through holes 21A penetrate the substrate 21 in the thickness direction. The substrate 21 is fixed to the mounting portion 13A by screws 22. The screws 22 are fixing members for fixing the substrate 21 to the housing 11. The screws 22 have a shank and a head. The shank passes through the through hole 21A and is fastened to the mounting portion 13A. The head is in contact with a first surface of the substrate 21.

[0011] The substrate 21 has a first surface and a second surface located on opposite sides to each other. The first surface is the surface of the substrate 21 located on the side opposite the lid 12. The second surface is the surface of the substrate 21 facing the lid 12.

[0012] Electronic components are provided on the first surface. The electronic components include a heat-generating element 23 that generates heat when power is applied. The heat-generating element is, for example, a semiconductor element such as a field effect transistor (FET). A heat dissipation material 24 is interposed between the portion of the second surface corresponding to the heat-generating element 23 and the lid 12. The heat dissipation material 24 is, for example, thermal grease. The peripheral edge of the second surface is in contact with the mounting portion 13A.

[0013] 1 , heat generated from the heat-generating element 23 is dissipated, for example, via a first heat dissipation path A1 and a second heat dissipation path A2. The first heat dissipation path A1 and the second heat dissipation path A2 are heat transfer paths between the heat-generating element 23 and the housing 11. The first heat dissipation path A1 includes the substrate 21, the screws 22, and the housing 11. The second heat dissipation path A2 includes the substrate 21, the heat dissipation material 24, the cover 12, and the housing 11. The heat transferred to the housing 11 via the first heat dissipation path A1 and the second heat dissipation path A2 is dissipated to the outside.

[0014] The electronic control device 10 is required to have improved heat dissipation properties. For this reason, in this embodiment, the following configuration is adopted as the heat dissipation structure of the electronic control device 10. <Heat Dissipation Structure of Electronic Control Device 10> As shown in FIG. 2 , the substrate 21 is a multilayer substrate. A multilayer substrate is a substrate having three or more conductor layers. The substrate 21 is, for example, a six-layer substrate and has first to sixth thin-film conductor layers L1 to L6. The first to sixth conductor layers L1 to L6 are stacked via an insulating layer L7. The conductor constituting the conductor layers is, for example, copper. Copper has superior electrical conductivity and thermal conductivity compared to, for example, resin. The insulating layer L7 is formed from a core material or prepreg. The core material and prepreg are each a layer of glass fiber impregnated with resin.

[0015] As shown in FIG. 2 , the first to sixth conductor layers L1 to L6 are arranged in this order from the first surface to the second surface of the substrate 21. The first conductor layer L1 includes a first earth layer E1. The first earth layer E1 is provided around the through hole 21A. The portion of the substrate 21 around the through hole 21A corresponds to the portion of the substrate 21 that contacts the housing 11. The portion of the substrate 21 that contacts the housing 11 corresponds to the mounting portion 13A of the substrate 21. That is, the substrate 21 has a contact portion that contacts the housing 11, and the contact portion is a portion that overlaps with the mounting portion 13A when viewed from the thickness direction of the substrate 21. The first earth layer E1 is exposed on the first surface of the substrate 21 and is in contact with the head of the screw 22. That is, the first earth layer E1 is electrically connected to the housing 11 via the screw 22. As shown in FIG. 3 , the first conductor layer L1 also includes, for example, a first wiring layer W1. The first wiring layer W1 is provided with a pattern wiring. A small gap is formed at the boundary between the first earth layer E1 and the first wiring layer W1. For the sake of convenience, the first wiring layer W1 is omitted from FIG. 2.

[0016] As shown in FIG. 2 , the second conductor layer L2 has a first ground layer G1. The first ground layer G1 extends from a portion of the substrate 21 corresponding to the heating element 23 to the through hole 21A. A portion of the first ground layer G1 faces the first earth layer E1 in the thickness direction of the substrate 21, via an insulating layer L7. The portion of the first ground layer G1 facing the first earth layer E1 is the portion of the first ground layer G1 surrounding the through hole 21. As shown in FIG. 4 , the first ground layer G1 has a plurality of first holes 31. The first holes 31 are arranged to surround the through hole 21A. The first holes 31 are through holes that penetrate the first ground layer G1 in the film thickness direction.

[0017] As shown in FIG. 2, the third conductor layer L3 includes a second earth layer E2 and a second ground layer G2. The second earth layer E2 is disposed around the through hole 21A. The second earth layer E2 faces a portion of the first ground layer G1 in the thickness direction of the substrate 21 via an insulating layer L7. The portion of the first ground layer G1 facing the second earth layer E2 is the portion of the first ground layer G1 surrounding the through hole 21. The second ground layer G2 extends from a portion of the substrate 21 corresponding to the heating element 23 to the vicinity of the second earth layer E2. As shown in FIG. 5, a small gap is formed at the boundary between the second earth layer E2 and the second ground layer G2.

[0018] As shown in FIG. 2 , the fourth conductor layer L4 has a third ground layer G3. The third ground layer G3 extends from a portion of the substrate 21 corresponding to the heating element 23 to the through hole 21A. A portion of the third ground layer G3 faces the second earth layer E2 in the thickness direction of the substrate 21 via an insulating layer L7. The portion of the third ground layer G3 facing the second earth layer E2 is the portion of the third ground layer G3 surrounding the through hole 21. As shown in FIG. 6 , the third ground layer G3 has a plurality of second holes 32. The number of the second holes 32 is the same as the number of the first holes 31, and they are arranged to surround the through hole 21A. The second holes 32 are through holes that penetrate the third ground layer G3 in the film thickness direction. The second holes 32 are arranged coaxially with the first holes 31.

[0019] As shown in FIG. 2 , the fifth conductor layer L5 includes a third earth layer E3 and a fourth ground layer G4. The third earth layer E3 is disposed around the through hole 21A. The third earth layer E3 extends from the periphery of the through hole 21A radially outward from the through hole 21A. The third earth layer E3 extends to a position away from the portion of the substrate 21 that contacts the housing 11. The third earth layer E3 faces a portion of the third ground layer G3 in the thickness direction of the substrate 21 via the insulating layer L7. The portion of the third ground layer G3 facing the third earth layer E3 includes the portion of the third ground layer G3 surrounding the through hole 21. The fourth ground layer G2 extends from the portion of the substrate 21 corresponding to the heating element 23 to the vicinity of the third earth layer E3. As shown in FIG. 7, a small gap is formed at the boundary between the third earth layer E3 and the fourth ground layer G4.

[0020] As shown in FIG. 2 , the sixth conductor layer L6 includes a fourth earth layer E4. The fourth earth layer E4 is provided around the through hole 21A. The fourth earth layer E4 is exposed on the second surface of the substrate 21 and is in contact with the mounting portion 13A. That is, the fourth earth layer E4 is electrically connected to the housing 11. As shown in FIG. 8 , the sixth conductor layer L6 also includes, for example, a second wiring layer W2. Pattern wiring is provided on the second wiring layer W2. A small gap is formed at the boundary between the fourth earth layer E4 and the second wiring layer W2. Note that the second wiring layer W2 is omitted from FIG. 2 for ease of explanation.

[0021] The substrate 21 has a plurality of first thermal vias V1. The number of the first thermal vias V1 is the same as the number of the first holes 31 and the second holes 32. The first thermal vias V1 are formed, for example, by driving a metal body such as copper, which has excellent thermal conductivity, into the substrate 21. The first thermal vias V1 have, for example, a circular cross-sectional shape. The first thermal vias V1 are arranged on the periphery of the through hole 21A. The first thermal vias V1 extend in the thickness direction of the substrate 21 and connect the first to fourth earth layers E1 to E4 to each other. The first thermal vias V1 are electrically connected to the first to fourth earth layers E1 to E4, while being electrically insulated from the first to fourth ground layers G1 to G4.

[0022] 3, 5, 7, and 8, the first thermal via V1 penetrates the substrate 21 in the thickness direction while contacting the first to fourth earth layers E1 to E4. The outer peripheral surface of the first thermal via V1 contacts each of the first to fourth earth layers E1 to E4, thereby ensuring electrical connection between the first thermal via V1 and the first to fourth earth layers E1 to E4.

[0023] As shown in Figure 4, the first thermal via V1 penetrates the substrate 21 in the thickness direction without contacting the first ground layer G1, which has a portion surrounding the through hole 21A. The first hole 31 has a larger outer diameter than the first thermal via V1. A gap is formed between the inner surface of the first hole 31 and the outer surface of the first thermal via V1. The gap ensures electrical insulation between the first thermal via V1 and the first ground layer G1.

[0024] As shown in Figure 6, the first thermal via V1 penetrates the substrate 21 in the thickness direction without contacting the third ground layer G3, which has a portion surrounding the through hole 21A. The second hole 32 has a larger outer diameter than the first thermal via V1. A gap is formed between the inner surface of the second hole 32 and the outer surface of the first thermal via V1. This gap ensures electrical insulation between the first thermal via V1 and the third ground layer G3.

[0025] The second ground layer G2 and the fourth ground layer G4 do not have a portion surrounding the through hole 21A. That is, when viewed from the thickness direction of the substrate 21, the second ground layer G2 and the fourth ground layer G4 do not overlap with the first thermal via V1. Because the second ground layer G2 does not contact the first thermal via V1, electrical insulation is ensured between the first thermal via V1 and the second ground layer G2. Furthermore, because the fourth ground layer G4 does not contact the first thermal via V1, electrical insulation is ensured between the first thermal via V1 and the fourth ground layer G4.

[0026] The substrate 21 has a second thermal via V2. The second thermal via V2 is formed, for example, by driving a metal such as copper, which has excellent thermal conductivity, into the substrate 21. The second thermal via V2 has, for example, a circular cross-sectional shape. The second thermal via V2 is disposed in a portion of the substrate 21 corresponding to the heat-generating element 23. The second thermal via V2 extends in the thickness direction of the substrate 21 and connects the first to fourth ground layers G1 to G4 to each other. A first end of the second thermal via V2 is exposed on the first surface of the substrate 21 and is in contact with the heat-generating element 23. In other words, the first to fourth ground layers G1 to G4 are electrically connected to the heat-generating element 23 via the second thermal via V2. A second end of the second thermal via V2 is exposed on the second surface of the substrate 21. The second end is the end of the second thermal via V2 opposite to the first end.

[0027] As shown by the arrows in FIG. 2 , heat generated by the heat-generating element 23 is transferred to the housing 11 via the second thermal via V2, the first to fourth ground layers G1 to G4, the first to fourth earth layers E1 to E4, the first thermal via V1, and the screw 22. A portion of the heat is transferred between the ground layers (G1 to G4) and the earth layers (E1 to E4) that face each other in the thickness direction of the substrate 21 via the insulating layer L7. A portion of the heat is transferred to the housing 11 via the first earth layer E1 and the screw 22. A portion of the heat is transferred to the housing 11 via the fourth earth layer E4. A portion of the heat is transferred to the housing 11 via the second thermal via V2, the heat dissipation material 24, and the lid 12. Note that the heat dissipation material 24 and the lid 12 are not shown in FIG. 2 . The heat transferred to the housing 11 is dissipated to the outside.

[0028] <Thermal resistance between two layers> Thermal resistance in thermal conduction is proportional to the length of an object and inversely proportional to the cross-sectional area of ​​the object. In other words, the shorter the length of an object and the wider the cross-sectional area of ​​the object, the smaller the thermal resistance in thermal conduction. Thermal resistance in thermal radiation is inversely proportional to the surface area of ​​an object. In other words, the wider the surface area of ​​an object, the smaller the thermal resistance in thermal radiation.

[0029] As shown in FIG. 9 , for example, in the first conductor layer L1, the first earth layer E1 has a first opposing surface E11. The first opposing surface E11 is part of the periphery of the first earth layer E1. The first wiring layer W1 has a second opposing surface W11. The second opposing surface W11 is part of the periphery of the first wiring layer W1 and has a contour shape corresponding to the first opposing surface E11. The first opposing surface E11 and the second opposing surface W11 face each other with a constant, small gap between them. The gap between the first opposing surface E11 and the second opposing surface W11 is narrower than the gap between the first to sixth conductor layers L1 to L6 in the thickness direction.

[0030] The opposing area between the first opposing surface E11 and the second opposing surface W11 is much smaller than the opposing area between the first earth layer E1, indicated by numerous dots in Figure 10, and the first ground layer G1 on the second conductor layer L2. This is because the thickness of the first conductor layer L1, including the first earth layer E1 and the first wiring layer W1, is extremely thin. Therefore, the thermal resistance between the first opposing surface E11 and the second opposing surface W11 is greater overall than the thermal resistance between the first earth layer E1 and the first ground layer G1. The same is true for each of the first to sixth conductor layers L1 to L6.

[0031] In this way, the thermal resistance between two layers facing each other in the thickness direction of the substrate 21 with the insulating layer L7 interposed therebetween is smaller than the thermal resistance between two adjacent layers located in the same plane. The thermal resistance between two layers facing each other in the thickness direction of the substrate 21 with the insulating layer L7 interposed therebetween becomes smaller as the opposing area of ​​the two layers increases, and also becomes smaller as the thickness of the insulating layer L7 becomes thinner.

[0032] Effects of the Embodiment The present embodiment has the following effects: (1) The substrate 21 has a plurality of conductor layers (L1 to L6) stacked with an insulating layer L7 interposed therebetween. The plurality of conductor layers include a first specific conductor layer having an earth layer configured to be electrically connected to the housing 11, and a second specific conductor layer having a ground layer configured to be electrically connected to the heating element 23.

[0033] The first specific conductor layer is the first conductor layer L1, the third conductor layer L3, or the fifth conductor layer L5. The first conductor layer L1 has a first earth layer E1, the third conductor layer L3 has a second earth layer E2, and the fifth conductor layer L5 has a third earth layer E3. The first to third earth layers E1 to E3 are each configured to be electrically connected to the housing 11.

[0034] The second specific conductor layer is the second conductor layer L2 or the fourth conductor layer L4. The second conductor layer L2 has a first ground layer G1, and the fourth conductor layer L4 has a third ground layer G3. The first ground layer G1 and the third ground layer G3 are each configured to be electrically connected to the heat generating element 23.

[0035] If the first specific conductor layer is the first conductor layer L1, the second specific conductor layer is the second conductor layer L2. The first earth layer E1 and the first ground layer G1 are at least partially opposed to each other in the thickness direction of the substrate 21 via the insulating layer L7.

[0036] If the first specific conductor layer is the third conductor layer L3, the second specific conductor layer is the second conductor layer L2 or the fourth conductor layer L4. The third conductor layer L3 and the first ground layer G1, or the third conductor layer L3 and the third ground layer G3, are at least partially opposed to each other in the thickness direction of the substrate 21 via the insulating layer L7.

[0037] If the first specific conductor layer is the fifth conductor layer L5, the second specific conductor layer is the fourth conductor layer L4. The third earth layer E3 and the third ground layer G3 are at least partially opposed to each other in the thickness direction of the substrate 21 via the insulating layer L7.

[0038] With this configuration, heat generated by the heat generating element 23 is transferred to the housing 11 via the ground layers (G1 to G4), the earth layers (E1 to E4), and the screws 22. The heat transferred to the housing 11 is dissipated to the outside. Heat is transferred between the portions where the earth layers (E1 to E3) and the ground layers (G1, G3) face each other in the thickness direction of the board 21 via the insulating layer L7. This improves the heat dissipation performance of the board 21 compared to when the earth layers (E1 to E3) and the ground layers (G1, G3) do not face each other in the thickness direction of the board 21 via the insulating layer L7.

[0039] (2) The earth layers (E1 to E3) and the ground layers (G1, G3) at least partially overlap in the thickness direction of the substrate 21 in the region where the substrate 21 contacts the housing 11. The portion of the substrate 21 that contacts the housing 11 is the portion of the substrate 21 that corresponds to the mounting portion 13A. This configuration further shortens the distance from the ground layers (G1, G3) to the housing 11. Because the thermal resistance between the ground layers (G1, G3) and the housing 11 is further reduced, the heat dissipation performance of the substrate 21 is improved.

[0040] (3) There are multiple pairs of first specific conductor layers and second specific conductor layers. The multiple pairs include, for example, a first pair consisting of the first conductor layer L1 and the second conductor layer L2, and a second pair consisting of the third conductor layer L3 and the fourth conductor layer L4. The first earth layer E1, the first ground layer G1, the second earth layer E2, and the third ground layer G3 are arranged in this order in the thickness direction of the board 21. That is, the earth layers (E1, E2) and the ground layers (G1, G3) are arranged alternately in the thickness direction of the board 21. This configuration increases the area where the earth layer and the ground layer face each other in the thickness direction of the board 21 via the insulating layer L7 across the entire board 21. This improves the heat dissipation of the board 21.

[0041] (4) The substrate 21 has a plurality of first thermal vias V1 that connect the plurality of earth layers (E1 to E4) to one another. The first thermal vias V1 are interlayer conductors that connect the earth layers of different conductor layers to one another. With this configuration, heat is transferred between the plurality of earth layers (E1 to E4) via the first thermal vias V1. This improves the heat dissipation performance of the substrate 21.

[0042] (5) The first ground layer G1 and the third ground layer G3 each have a hole 31. The first thermal via V1 extends through the hole 31 without contacting each of the ground layers G1 and G3. With this configuration, the earth layers (E1 to E3) and the ground layers (G1, G3) can be electrically insulated from each other while ensuring an area where the earth layers (E1 to E3) and the ground layers (G1, G3) face each other in the thickness direction of the substrate 21 via the insulating layer L7.

[0043] (6) The substrate 21 has a contact portion that contacts the housing 11. At least one (E3) of the multiple earth layers (E1 to E4) faces a part of the ground layer (G3) in the thickness direction of the substrate 21 via the insulating layer L7 at a position corresponding to the contact portion of the substrate 21 and at a position away from the contact portion. This configuration increases the area where the earth layer (E3) and the ground layer (G3) face each other in the thickness direction of the substrate 21 via the insulating layer L7. This improves the heat dissipation of the substrate 21.

[0044] Other Embodiments This embodiment may be modified as follows: When the heat dissipation required for the substrate 21 can be ensured, the heat dissipation material 24 between the substrate 21 and the lid 12 may be omitted.

[0045] The heating element 23 may be provided on the second surface of the substrate 21. In this case, a heat dissipation material 24 is interposed between the heating element 23 and the lid 12. The substrate 21 may be fixed to the housing 11 by, for example, a pin instead of the screw 22. The pin is a fixing member for fixing the substrate 21 to the housing 11.

[0046] The first thermal via V1 may be singular. The earth layer that faces a portion of the ground layer in the thickness direction of the substrate 21 via the insulating layer L7 at a position corresponding to the contact portion of the substrate 21 and a position away from the contact portion is not limited to the third earth layer E3. The earth layer that extends to a position away from the contact portion of the substrate 21 is determined by the product specifications. At least one of the first to fourth earth layers E1 to E4 may extend to a position away from the contact portion of the substrate 21. The extent to which the earth layer extends is also determined by the product specifications.

[0047] The substrate 21 is not limited to a six-layer substrate having the first to sixth conductor layers L1 to L6. The substrate 21 may be, for example, a three-layer substrate or a four-layer substrate. The earth layers (E1 to E3) and the ground layers (G1, G3) do not have to be arranged alternately in the thickness direction of the substrate 21. For example, the first earth layer E1, the first ground layer G1, the third ground layer G3, and the second earth layer E2 may be arranged in this order in the thickness direction of the substrate 21.

[0048] The electronic control unit 10 is not limited to use in vehicles. The electronic control unit 10 can be used to control various mechanical devices. The expression "at least one" used in this specification means "one or more" of the desired options. As an example, the expression "at least one" used in this specification means "only one option" or "both of two options" if the number of options is two. As another example, the expression "at least one" used in this specification means "only one option" or "any combination of two or more options" if the number of options is three or more.

Claims

1. a substrate configured to be attached to a metal housing by a metal fixing member, the substrate having a plurality of conductor layers stacked with insulating layers interposed therebetween; a heat generating element configured to generate heat when energized; The plurality of conductor layers include: a first specific conductor layer having a ground layer configured to be electrically connected to the housing; a second specific conductor layer having a ground layer configured to be electrically connected to the heat generating element; the earth layer and the ground layer are at least partially opposed to each other in a thickness direction of the substrate via the insulating layer, The earth layer and the ground layer at least partially overlap in the thickness direction of the board in the region where the board contacts the housing.

2. There are a plurality of pairs of the first specific conductor layer and the second specific conductor layer, 2. The electronic control device according to claim 1, wherein a plurality of the earth layers and a plurality of the ground layers are alternately arranged in the thickness direction of the substrate.

3. 3. The electronic control device according to claim 2, wherein the substrate has one or more interlayer conductors connecting the plurality of ground layers to each other.

4. 4. The electronic control device according to claim 3, wherein the ground layer has a through hole, and the interlayer conductor extends through the through hole without contacting the ground layer.

5. the substrate has a contact portion that contacts the housing; 3. The electronic control device according to claim 2, wherein at least one of the plurality of earth layers faces a portion of the ground layer in the thickness direction of the substrate via the insulating layer at a position corresponding to the contact portion and at a position away from the contact portion.