Electronic control unit

Abstract

The present invention provides an electronic control device. A housing of the electronic control device has a housing-side contact surface that contacts an end portion of a printed circuit board. A cover has a cover-side contact surface that, by contacting the end portion of the printed circuit board, sandwiches the end portion of the printed circuit board together with the housing-side contact surface. A through hole is provided in a clamped portion of the printed circuit board that is clamped by the housing-side contact surface and the cover-side contact surface.

Description

Technical Field

[0001] The present invention relates to an electronic control device including a housing that houses a printed circuit board. Background Art

[0002] In a vehicle, an electronic control device is mounted as an engine control unit or a control unit for an automatic transmission. Generally, an electronic control device includes a printed circuit board on which electronic components are mounted and a housing that houses the printed circuit board. The prior art related to such an electronic control device is disclosed in Patent Document 1.

[0003] The housing of the electronic control device disclosed in Japanese Unexamined Patent Application Publication No. 2019-46894 includes: a housing having an opening and housing a printed circuit board therein; and a lid that closes the opening of the housing.

[0004] Inside the housing, the printed circuit board is fixed to the housing using screws. Specifically, a support portion that supports an end portion of the printed circuit board is provided inside the housing. Internal threaded holes are formed in the contact surfaces of the support portion that contact the printed circuit board. The end portion of the printed circuit board has through holes through which the screws pass. When the screws are threadedly fastened to the internal threaded holes of the support portion of the housing, the end portion of the printed circuit board is clamped between the head of the screw and the support portion.

[0005] When the end portion of the printed circuit board is clamped between the head of the screw and the support portion of the housing, the end portion of the printed circuit board is compressed. If the end portion of the printed circuit board is compressed, stress is generated at the soldered portions of the electronic components disposed around the end portion of the printed circuit board. The connection reliability between the electronic components and the printed circuit board may be impaired.

[0006] An object of the present invention is to provide an electronic control device capable of reducing stress generated at the soldered portions of electronic components connected to a printed circuit board. Summary of the Invention

[0007] In Technical Solution 1, there is provided an electronic control device, which has:

[0008] a housing having an opening and housing a printed circuit board therein; and

[0009] a lid that closes the opening of the housing,

[0010] wherein an outer peripheral edge of the lid is fixed so as to overlap an edge of the opening of the housing,

[0011] at a position inside the edge of the opening of the housing, the housing has a housing-side contact surface that contacts an end portion of the printed circuit board,

[0012] The cover has a cover-side contact surface which, by contacting the end portion of the printed circuit board, clamps the end portion of the printed circuit board together with the housing-side contact surface.

[0013] A through-hole is provided in the clamped portion of the printed circuit board that is clamped by the housing-side contact surface and the cover-side contact surface.

[0014] That is, the housing of the electronic control device has a housing-side contact surface that contacts the end portion of the printed circuit board. The cover has a cover-side contact surface which, by contacting the end portion of the printed circuit board, clamps the end portion of the printed circuit board together with the housing-side contact surface. Compared with the case of fixing the printed circuit board to the housing using screws, the end portion of the printed circuit board can be clamped with a wider surface. The compressive force applied to the end portion of the printed circuit board can be dispersed. The stress generated at the soldering portion of the electronic components arranged around the end portion of the printed circuit board can be reduced.

[0015] In addition, a through-hole is provided in the clamped portion of the printed circuit board that is clamped by the housing-side contact surface and the cover-side contact surface. A through-hole is provided in the clamped portion of the printed circuit board. The through-hole becomes a cylindrical reinforcing material extending in the thickness direction of the printed circuit board, so the strength in the thickness direction of the printed circuit board can be improved.

[0016] Preferably, a copper foil is provided on the surface of the clamped portion of the printed circuit board, and the hole of the through-hole penetrates the copper foil. Therefore, the insulating layer (base material) of the printed circuit board can be protected, and the strength in the thickness direction of the printed circuit board can be improved.

[0017] Preferably, the hole of the through-hole is filled with a filling member, and a plated portion subjected to plating processing is provided on the surface of the clamped portion of the printed circuit board, and the plated portion covers the through-hole and the filling member. Since the hole of the through-hole is filled with a filling member, the through-hole can be strengthened, and the strength in the thickness direction of the clamped portion of the printed circuit board becomes higher. And a plated portion subjected to plating processing is provided on the surface of the clamped portion of the printed circuit board. This plated portion covers the through-hole and the filling member. Therefore, the contact area of the plated portion with respect to the housing and the cover becomes larger, and the heat dissipation effect is also improved.

[0018] Preferably, the printed circuit board is constituted by laminating a plurality of insulating layers, and based on the thickness direction of the printed circuit board, the elastic modulus of the outermost layer on the outermost side is lower than the elastic modulus of the adjacent layer adjacent to the outermost layer. Since the outermost layer of the printed circuit board is easily deformed, the force generated by being clamped by the cover-side contact surface and the housing-side contact surface can be dispersed to the entire printed circuit board. The stress generated at the soldering portion of the electronic components can be alleviated.

[0019] Preferably, a plurality of the housing-side contact surfaces and the lid-side contact surfaces are respectively provided, and the plurality of the housing-side contact surfaces and the lid-side contact surfaces are arranged along a pair of edges extending in the same direction in the printed circuit board. Since both ends of the printed circuit board are supported, the printed circuit board can be reliably fixed relative to the housing. Description of the Drawings

[0020] Figure 1 is a perspective view of the electronic control device according to Embodiment 1.

[0021] Figure 2 is Figure 1 an exploded perspective view of the illustrated electronic control device.

[0022] Figure 3 is an enlarged view showing a portion surrounded by the line shown in Figure 2 3.

[0023] Figure 4 is Figure 1 a cross-sectional view taken along the line 4-4 of

[0024] Figure 5 is a cross-sectional view of the electronic control device according to Embodiment 2. Detailed Description of the Embodiments

[0025] Hereinafter, embodiments will be described based on the drawings.

[0026] <Embodiment 1>

[0027] In Figure 1 is shown an electronic control device 10 applicable to an engine control unit or the like according to Embodiment 1, which can be mounted on a vehicle body (e.g., a four-wheeled vehicle).

[0028] Refer to Figure 1 and Figure 2 . The electronic control device 10 includes: a printed circuit board 20 having a wiring pattern (not shown) of an electronic circuit; a housing 30 having an opening 31 that opens upward and accommodating the printed circuit board 20 therein; and a lid 40 that closes the opening 31 of the housing 30.

[0029] For ease of explanation, the thickness direction of the printed circuit board 20 is set as the up-and-down direction. In the figure, "up" refers to the upper side and "down" refers to the lower side. It should be noted that the up-and-down direction does not necessarily correspond to the state of the electronic control device 10 mounted on the vehicle body.

[0030] (Printed Circuit Board)

[0031] Electronic components (not shown) are mounted on the upper surface 21 and the lower surface 22 of the printed circuit board 20. The end 23 of the printed circuit board 20 has a pair of long edges 24, 25 (a pair of edges) along the long side direction of the printed circuit board 20 and a pair of short edges 26, 27 along the short side direction of the printed circuit board 20. The long edge on which the two connectors 11, 12 capable of connecting to an external device are arranged among the pair of long edges 24, 25 is set as the first long edge 24, and the long edge paired with the first long edge 24 is set as the second long edge 25.

[0032] (Housing)

[0033] The housing 30 is made of a metal product (aluminum die-cast) with excellent heat conductivity such as aluminum and is box-shaped. Specifically, the housing 30 is configured such that a plate-shaped bottom 32 opposed to the lower surface 22 of the printed circuit board 20 and a wall portion 33 provided along the edge of the bottom 32 and capable of surrounding the printed circuit board 20 are integrated. The wall portion 33 is not provided at the portion where the connectors 11, 12 are arranged.

[0034] The outer peripheral edge 45 of the cover 40 can overlap with the upper surface 34 of the wall portion 33 (the edge of the opening 31 of the housing 30). The upper surface 34 of the wall portion 33 has an internal thread hole 34a capable of being fastened with a screw 13 for fixing the cover 40.

[0035] Inside the housing 30, there are a plurality of (for example, four) housing-side support portions 36, 37 capable of supporting the printed circuit board 20. The housing-side support portions 36, 37 have two first housing-side support portions 36 capable of supporting the first long edge 24 of the printed circuit board 20 and two second housing-side support portions 37 capable of supporting the second long edge 25 of the printed circuit board 20. Each of the housing-side support portions 36, 37 is integrally formed with the upper surface 32a of the bottom 32 and the inner peripheral surface 33a of the wall portion 33.

[0036] (Cover)

[0037] The cover 40 is made of a metal plate that is lighter and lower in cost than a metal material (made of an aluminum die-cast). The cover 40 has an opposed surface 42 capable of opposing the upper surface 21 of the printed circuit board 20. The outer peripheral edge 45 of the cover 40 has a through hole 46 through which the screw 13 can pass.

[0038] The opposed surface 42 has a plurality of (for example, four) cover-side support portions 43, 44 capable of supporting the upper surface 21 of the printed circuit board 20. Each of the cover-side support portions 43, 44 protrudes from the opposed surface 42 toward the printed circuit board 20. The cover-side support portions 43, 44 have two first cover-side support portions 43 capable of supporting the first long edge 24 of the printed circuit board 20 and two second cover-side support portions 44 capable of supporting the second long edge 25 of the printed circuit board 20.

[0039] (Clamping portion of the printed circuit board)

[0040] A portion of the first long edge 24 of the printed circuit board 20 that is clamped between the first housing-side support portion 36 and the first cover-side support portion 43 is defined as the first clamping portion 28. There are two first clamping portions 28. A portion of the second long edge 25 of the printed circuit board 20 that is clamped between the second housing-side support portion 37 and the second cover-side support portion 44 is defined as the second clamping portion 29. There are two second clamping portions 29.

[0041] Hereinafter, the structure of the second clamping portion 29 will be described, but this description also applies to the first clamping portion 28.

[0042] (Layers constituting the printed circuit board)

[0043] Refer to Figure 3 and Figure 4 . The printed circuit board 20 is a multilayer substrate and is composed of a plurality of (for example, five) layers 61 to 65. Each of the layers 61 to 65 is made of an insulator. The five layers 61 to 65 include a first outer layer 61 (outermost layer) located on the uppermost side (cover 40 side), a second outer layer 62 (outermost layer) located on the lowermost side (housing 30 side), a first inner layer 63 (adjacent layer) adjacent to the first outer layer 61, a second inner layer 64 (adjacent layer) adjacent to the second outer layer 62, and a third inner layer 65 between the first inner layer 63 and the second inner layer 64.

[0044] The first outer layer 61 and the second outer layer 62 are each composed of inorganic fibers such as glass fabric and a thermosetting resin composition. The thermosetting resin composition contains an epoxy resin and a low-elasticity agent. The first inner layer 63 to the third inner layer 65 are composed of inorganic fibers such as glass fabric and an epoxy resin.

[0045] A plurality of (for example, five) through holes 50 penetrating the first outer layer 61 to the second outer layer 62 are provided in the clamping portion.

[0046] (Copper foil)

[0047] A first copper foil 71 is provided on the upper surface 29a (surface of the clamping portion) of the second clamping portion 29. The first copper foil 71 contacts the lower surface 44a (cover-side contact surface) of the second cover-side support portion 44. The first copper foil 71 is a part of the copper foil pasted on the surface of the first outer layer 61 during the manufacture of the printed circuit board 20 and is formed together with the wiring pattern of the first outer layer 61.

[0048] A second copper foil 72 is provided on the lower surface 29b (the surface of the clamping portion) of the second clamping portion 29. The second copper foil 72 is in contact with the upper surface 37a (the contact surface on the housing side) of the second housing side support portion 37. The second copper foil 72 is a part of the copper foil that covers the surface of the second outer layer 62 when manufacturing the printed circuit board 20, and is formed together with the wiring pattern of the second outer layer 62. It should be noted that the structure may also be such that only one of the first copper foil 71 and the second copper foil 72 is provided.

[0049] The hole 50a of the through hole 50 penetrates both the first copper foil 71 and the second copper foil 72.

[0050] (Elastic modulus of the insulating layer)

[0051] The elastic modulus of the first outer layer 61 is lower than the elastic modulus of the first inner layer 63. The elastic modulus of the second outer layer 62 is lower than the elastic modulus of the second inner layer 64. The elastic modulus of the first outer layer 61 is equal to the elastic modulus of the second outer layer 62. The elastic moduli of the first inner layer 63 to the third inner layer 65 are equal to each other.

[0052] <Effect of Example 1>

[0053] Refer to Figure 4 . The second long edge 25 of the printed circuit board 20 is clamped by the upper surface 37a of the second housing side support portion 37 and the lower surface 44a of the second cover side support portion 44. Compared with the case of fixing the printed circuit board 20 to the housing 30 using screws as in the prior art, it is possible to clamp the second long edge 25 of the printed circuit board 20 with a wider surface. It is possible to reduce the stress generated at the soldering portions of the electronic components arranged around the second clamping portion 29 of the printed circuit board 20.

[0054] In addition, a plurality of (for example, five) through holes 50 are provided in the second clamping portion 29 of the printed circuit board 20. Each through hole 50 serves as a cylindrical reinforcing material extending in the thickness direction of the printed circuit board 20, so that the strength in the thickness direction of the printed circuit board 20 can be improved.

[0055] In addition, a first copper foil 71 is provided on the upper surface 29a of the second clamping portion 29. A second copper foil 72 is provided on the lower surface 29b of the second clamping portion 29. Therefore, it is possible to protect the first outer layer 61 and the second outer layer 62 of the printed circuit board 20, and to improve the strength in the thickness direction of the printed circuit board 20.

[0056] In addition, the housing 30 is manufactured using an aluminum die-cast, and the cover 40 is manufactured using a metal plate. Therefore, the second clamping portion 29 of the printed circuit board 20 can be used as the frame ground wire of the circuit.

[0057] In addition, the elastic modulus of the first outer layer 61 is lower than that of the first inner layer 63. The elastic modulus of the second outer layer 62 is lower than that of the second inner layer 64. That is, the first outer layer 61 and the second outer layer 62 in the second clamping portion 29 of the printed circuit board 20 are more easily deformed than the first inner layer 63 to the third inner layer 65. Since the force generated by the clamping of the cover-side support portion 44 and the housing-side support portion 37 can be dispersed over the entire printed circuit board 20, the stress generated in the soldered portions of the electronic components arranged around the second clamping portion 29 can be reduced.

[0058] In addition, referring to Figure 2 . The first long edge 24 of the printed circuit board 20 is supported by two first housing-side support portions 36 and two first cover-side support portions 43. The second long edge 25 of the printed circuit board 20 is supported by two first housing-side support portions 36 and two first cover-side support portions 43. Since both ends 24 and 25 of the printed circuit board 20 are supported, the printed circuit board 20 can be reliably fixed to the housing 30. In addition, instead of the structure for supporting the long edges 24 and 25, the short edges 26 and 27 may be supported.

[0059] The effects of the above invention can also be achieved in the second embodiment described below.

[0060] <Second Embodiment>

[0061] Figure 5 An electronic control device 10A of the second embodiment is shown. For the structures common to the electronic control device 10 of the first embodiment (refer to Figure 4 ), the same reference numerals as those in the first embodiment are assigned, and the description thereof is omitted.

[0062] The holes 50a of the respective through holes 50 are filled with a filling member 80 (e.g., a resin material). A first copper plating portion 91 subjected to copper plating is provided on the upper surface 29a of the second clamping portion 29. The first copper plating portion 91 covers the through holes 50 and the filling member 80. The first copper plating portion 91 is in contact with the lower surface 44a of the second cover-side support portion 44.

[0063] A second copper plating portion 92 subjected to copper plating is provided on the lower surface 29b of the second clamping portion 29. The second copper plating portion 92 covers the through holes 50 and the filling member 80. The first copper plating portion 91 is in contact with the upper surface 37a of the second housing-side support portion 37. It should be noted that the raw material for the plating process is not limited to copper, and a metal suitable for the plating process can be selected. It should be noted that a structure in which only one of the first copper plating portion 91 and the second copper plating portion 92 is provided may also be used.

[0064] (Effects of the Second Embodiment)

[0065] Since the hole 50a of the through hole 50 is filled with the filling member 80, the through hole 50 can be strengthened, and the strength in the thickness direction of the second clamping portion 29 becomes higher.

[0066] Moreover, a first copper plating portion 91 subjected to copper plating is provided on the upper surface 29a of the second clamping portion 29. A second copper plating portion 92 subjected to copper plating is provided on the lower surface 29b of the second clamping portion 29. These first plating portion and second plating portion cover the through hole 50 and the filling member 80. Therefore, the contact area of the first plating portion and the second plating portion with respect to the housing 30 and the lid 40 becomes larger, and the heat dissipation effect is also improved.

[0067] The present invention is not limited to the embodiments as long as the functions and effects of the present invention are achieved.

Claims

1. An electronic control device, wherein, The electronic control device has: a housing having an opening and accommodating a printed circuit board therein; and a cover for closing the opening of the housing, wherein an outer peripheral edge of the cover is fixed overlapping an edge of the opening of the housing, at a position inside the edge of the opening of the housing, the housing has a housing-side contact surface in contact with an end portion of the printed circuit board, the cover has a cover-side contact surface which, by contacting the end portion of the printed circuit board, sandwiches the end portion of the printed circuit board together with the housing-side contact surface, a through hole is provided in a clamped portion of the printed circuit board clamped by the housing-side contact surface and the cover-side contact surface.

2. The electronic control device according to claim 1, wherein a copper foil is provided on a surface of the clamped portion of the printed circuit board, and the hole of the through hole penetrates the copper foil.

3. The electronic control device according to claim 1, wherein the hole of the through hole is filled with a filling member, and a plated portion subjected to plating is provided on a surface of the clamped portion of the printed circuit board, the plated portion covers the through hole and the filling member.

4. The electronic control device according to claim 1, wherein the printed circuit board is formed by laminating a plurality of insulating layers, based on the thickness direction of the printed circuit board, the outermost layer has a lower elastic modulus than an adjacent layer adjacent to the outermost layer.

5. The electronic control device according to claim 2, wherein the printed circuit board is formed by laminating a plurality of insulating layers, based on the thickness direction of the printed circuit board, the outermost layer has a lower elastic modulus than an adjacent layer adjacent to the outermost layer.

6. The electronic control device according to claim 3, wherein the printed circuit board is formed by laminating a plurality of insulating layers, based on the thickness direction of the printed circuit board, the outermost layer has a lower elastic modulus than an adjacent layer adjacent to the outermost layer.

7. The electronic control device according to any one of claims 1-6, wherein a plurality of the housing-side contact surfaces and the cover-side contact surfaces are provided respectively, the plurality of housing-side contact surfaces and the cover-side contact surfaces are arranged along a pair of edges extending in the same direction in the printed circuit board.

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