Electronic Control Unit

Abstract

To provide an electronic control device which enables reduction of stress generated in a soldered portion of an electronic component connected to a printed circuit board.SOLUTION: A case 30 of an electronic control device 10 has a case side contact surface 37a which contacts with an end part 25 of a printed circuit board 20. A cover 40 has a cover side contact surface 44a which contacts with the end part 25 of the printed circuit board 20 to sandwich the end part 25 of the printed circuit board 20 with the case side contact surface 37a. Through vias 50 are provided in a sandwiched part 29, which is sandwiched by the case side contact surface 37a and the cover side contact surface 44a, of the printed circuit board 20.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an electronic control device having a case in which a printed circuit board is housed. [Background technology]

[0002] Vehicles are equipped with electronic control devices as engine control units and automatic transmission control units. In general, electronic control devices are composed of a printed circuit board on which electronic components are mounted and a housing that houses the printed circuit board. Patent Document 1 discloses a conventional technique related to such electronic control devices.

[0003] The housing of the electronic control device disclosed in Patent Document 1 includes a case having an opening and housing a printed circuit board therein, and a cover that closes the opening of the case.

[0004] Inside the case, the printed circuit board is fixed to the case using screws. More specifically, a support portion that supports an end portion of the printed circuit board is provided inside the case. A female screw hole is formed in a contact surface of the support portion that contacts the printed circuit board. The end portion of the printed circuit board has a through hole through which the screw passes. When the screw is screwed into the female screw hole of the support portion of the case, the end portion of the printed circuit board is sandwiched between the head of the screw and the support portion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-46894 A Summary of the Invention [Problem to be solved by the invention]

[0006] When the end of the printed circuit board is pinched between the head of the screw and the support of the case, the end of the printed circuit board is compressed. When the end of the printed circuit board is compressed, stress is generated in the soldered parts of the electronic components arranged around the end of the printed circuit board. This may cause a loss of connection reliability between the electronic components and the printed circuit board.

[0007] An object of the present invention is to provide an electronic control device that can reduce stress generated in soldered portions of electronic components connected to a printed circuit board. [Means for solving the problem]

[0008] In claim 1, a case having an opening and housing a printed circuit board therein is provided. a cover closing the opening of the case, The outer periphery of the cover is overlapped with and fixed to the edge of the opening of the case, the case has a case-side contact surface that is in contact with an end of the printed circuit board on the inner side of the edge of the opening of the case, the cover has a cover-side contact surface that is in contact with the end of the printed circuit board and thereby sandwiches the end of the printed circuit board together with the case-side contact surface, An electronic control device is provided, wherein a through via is provided in a sandwiched portion of the printed circuit board sandwiched between the case side contact surface and the cover side contact surface.

[0009] As described in claim 2, preferably, a copper foil is provided on a surface of the sandwiching portion of the printed circuit board, and the through via hole passes through the copper foil.

[0010] As described in claim 3, preferably, the hole of the through via is filled with a filling material, and the surface of the clamping portion of the printed circuit board is provided with a plated portion that is plated, and the plated portion covers the through via and the filling material.

[0011] As described in claim 4, preferably, the printed circuit board is constructed by stacking a plurality of insulating layers, and the elastic modulus of the outermost layer, based on the thickness direction of the printed circuit board, is lower than the elastic modulus of an adjacent layer adjacent to the outermost layer.

[0012] As described in claim 5, preferably, a plurality of the case side contact surfaces and a plurality of the cover support portions are provided, and the plurality of the case side contact surfaces and the cover support portions are arranged along a pair of edges extending in the same direction within the printed circuit board. Effect of the Invention

[0013] In claim 1, the case of the electronic control device has a case-side contact surface that contacts the end of the printed circuit board. The cover has a cover-side contact surface that contacts the end of the printed circuit board and, together with the case-side contact surface, sandwiches the end of the printed circuit board. Compared to a case in which the printed circuit board is fixed to the case using a screw, the end of the printed circuit board can be sandwiched over a wider surface. The compressive force applied to the end of the printed circuit board can be dispersed. The stress generated at the soldering points of the electronic components arranged around the end of the printed circuit board can be reduced.

[0014] In addition, a through via is provided in a sandwiched portion of the printed circuit board that is sandwiched between the case-side contact surface and the cover-side contact surface. The through via serves as a cylindrical reinforcing member extending in the thickness direction of the printed circuit board, thereby increasing the strength of the printed circuit board in the thickness direction.

[0015] In claim 2, copper foil is provided on the surface of the sandwiched portion of the printed circuit board, and the through via holes penetrate the copper foil, which makes it possible to protect the insulating layer (base material) of the printed circuit board and increase the strength of the printed circuit board in the thickness direction.

[0016] In claim 3, the through via hole is filled with a filling member, and the surface of the sandwiching portion of the printed circuit board is provided with a plated portion. The plated portion covers the through via and the filling member. Since the through via hole is filled with the filling member, the through via can be reinforced, and the strength of the sandwiching portion of the printed circuit board in the thickness direction is increased. Furthermore, the surface of the sandwiching portion of the printed circuit board is provided with a plated portion. This plated portion covers the through via and the filling member. Therefore, the contact area of ​​the plated portion with the case and cover is increased, and the heat dissipation effect is improved.

[0017] In claim 4, the printed circuit board is configured by laminating a plurality of insulating layers. With reference to the thickness direction of the printed circuit board, the elastic modulus of the outermost layer 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 sandwiched between the cover side support part and the case side support part can be dispersed to the entire printed circuit board. The stress generated in the soldered part of the electronic component can be alleviated.

[0018] In claim 5, a plurality of case side contact surfaces and a plurality of cover support parts are provided. The plurality of case side contact surfaces and cover support parts 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 to the case. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of an electronic control device according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the electronic control device shown in FIG. [Diagram 3] FIG. 3 is an enlarged view of the area surrounded by the line indicated by 3 in FIG. 2. [Figure 4] 4 is a cross-sectional view taken along line 4-4 of FIG. 1. [Diagram 5] FIG. 11 is a cross-sectional view of an electronic control device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The embodiment will be described below with reference to the accompanying drawings.

[0021] <Example 1> FIG. 1 shows an electronic control device 10 applicable to an engine control unit or the like according to a first embodiment, which can be attached to the body of a vehicle (for example, a four-wheeled vehicle).

[0022] 1 and 2, the electronic control device 10 includes a printed circuit board 20 having a wiring pattern (not shown) of an electronic circuit, a case 30 having an opening 31 that opens upward and housing the printed circuit board 20 therein, and a cover 40 that closes the opening 31 of the case 30.

[0023] For convenience of explanation, the thickness direction of the printed circuit board 20 is defined as the up-down direction. In the drawing, Up indicates the upward direction, and Dn indicates the downward direction. Note that the up-down direction does not necessarily correspond to the state of the electronic control device 1010 attached to the vehicle body.

[0024] (Printed circuit board) Electronic components (not shown) are mounted on an upper surface 21 and a lower surface 22 of the printed circuit board 20. An end portion 23 of the printed circuit board 20 has a pair of longitudinal edges 24, 25 (a pair of edges) extending along the longitudinal direction of the printed circuit board 20, and a pair of short edges 26, 27 extending along the short direction of the printed circuit board 20. Of the pair of longitudinal edges 24, 25, the edge on which two connectors 11, 12 connectable to external devices are disposed is referred to as a first longitudinal edge 24, and the edge paired with the first longitudinal edge 24 is referred to as a second longitudinal edge 25.

[0025] (case) The case 30 is made of a metal (aluminum die-cast) having excellent thermal conductivity such as aluminum, and has a box shape. In detail, the case 30 is integrally formed with a plate-shaped bottom 32 facing the lower surface 22 of the printed circuit board 20 and a wall 33 provided along the edge of the bottom 32 and capable of surrounding the printed circuit board 20. The wall 33 is not provided in the area where the connectors 11, 12 are arranged.

[0026] An outer peripheral edge 45 of the cover 40 can be overlapped with an upper surface 34 (the edge of the opening 31 of the case 30) of the wall portion 33. The upper surface 34 of the wall portion 33 has a female screw hole 34a into which a screw 13 for fixing the cover 40 can be fastened.

[0027] The case 30 has a plurality of (e.g., four) case side support parts 36, 37 capable of supporting the printed circuit board 20 inside. The case side support parts 36, 37 have two first case side support parts 36, 36 capable of supporting the first longitudinal edge 24 of the printed circuit board 20, and two second case side support parts 37, 37 capable of supporting the second longitudinal edge 25 of the printed circuit board 20. Each of the case side support parts 36, 37 is integrally formed with an upper surface 32a of the bottom part 32 and an inner peripheral surface 33a of the wall part 33.

[0028] (cover) The cover 40 is made of sheet metal, which is lighter and less expensive than metal materials (aluminum die-cast). The cover 40 has an opposing surface 42 that can face the upper surface 21 of the printed circuit board 20. An outer peripheral edge 45 of the cover 40 has through holes 46 through which the screws 13 can pass.

[0029] The facing surface 42 has a plurality of (for example, four) cover side support parts 43, 44 capable of supporting the upper surface 21 of the printed circuit board 20. Each of the cover side support parts 43, 44 protrudes from the facing surface 42 toward the printed circuit board 20. The cover side support parts 43, 44 have two first cover side support parts 43, 44 capable of supporting a first longitudinal edge 24 of the printed circuit board 20, and two second cover side support parts 44, 44 capable of supporting a second longitudinal edge 25 of the printed circuit board 20.

[0030] (Pin-up part of printed circuit board) Of the first long side edge 24 of the printed circuit board 20, a portion sandwiched between the first case side support portion 36 and the first cover side support portion 43 is referred to as a first sandwiching portion 28. Two first sandwiching portions 28 are provided. Of the second long side edge 25 of the printed circuit board 20, a portion sandwiched between the second case side support portion 37 and the second cover side support portion 44 is referred to as a second sandwiching portion 29. Two first sandwiching portions 28 are provided.

[0031] The configuration of second clamping portion 29 will be described below, but this description also applies to first clamping portion 28.

[0032] (Layer that makes up a printed circuit board) 3 and 4. The printed circuit board 20 is a multi-layer board and is composed of a plurality of (for example, five) layers 61 to 65. Each of the layers 61 to 65 is composed of an insulator. The five layers 61 to 65 include a first outer layer 61 (outermost layer) located on the uppermost side (closer to the cover 40), a second outer layer 62 (outermost layer) located on the lowermost side (closer to the case 30), 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.

[0033] The first outer layer 61 and the second outer layer 62 are each composed of inorganic fibers such as woven glass fabric and a thermosetting resin composition. The thermosetting resin composition contains an epoxy resin and an elasticity reducing agent. The first inner layer 63 to the third inner layer 65 are each composed of inorganic fibers such as woven glass fabric and an epoxy resin.

[0034] In the sandwiching portion, a plurality of (for example, five) through vias 50 penetrating from the first outer layer 61 to the second outer layer 62 are provided.

[0035] (copper foil) A first copper foil 71 is provided on an upper surface 29a (surface of the sandwiching portion) of the second sandwiching portion 29. The first copper foil 71 is in contact with a lower surface 44a (cover side contact surface) of the second cover side supporting portion 44. The first copper foil 71 is a part of the copper foil that is attached to the surface of the first outer layer 61 when manufacturing the printed circuit board 20, and is formed together with the wiring pattern of the first outer layer 61.

[0036] A second copper foil 72 is provided on the lower surface 29b (surface of the sandwiching portion) of the second sandwiching portion 29. The second copper foil 72 is in contact with the upper surface 37a (case side contact surface) of the second case side supporting 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. Note that a configuration in which only either the first copper foil 71 or the second copper foil 72 is provided may also be used.

[0037] The hole 50 a of the through via 50 penetrates both the first copper foil 71 and the second copper foil 72 .

[0038] (Elastic modulus of insulating layer) 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. The elastic modulus of the first outer layer 61 is equal to that 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.

[0039] <Effects of Example 1> Please refer to Fig. 4. The second long edge 25 of the printed circuit board 20 is sandwiched between the upper surface 37a of the second case side support part 37 and the lower surface 44a of the second cover side support part 44. Compared to the case where the printed circuit board 20 is fixed to the case 30 using screws as in the conventional technology, the second long edge 25 of the printed circuit board 20 can be sandwiched over a wider surface. Stress generated in the soldered portions of the electronic components arranged around the second sandwiching part 29 of the printed circuit board 20 can be reduced.

[0040] In addition, a plurality of (for example, five) through vias 50 are provided in the second sandwiching portion 29 of the printed circuit board 20. Each through via 50 serves as a cylindrical reinforcing member extending in the thickness direction of the printed circuit board 20, and therefore the strength of the printed circuit board 20 in the thickness direction can be increased.

[0041] In addition, a first copper foil 71 is provided on an upper surface 29a of the second sandwiching portion 29. A second copper foil 72 is provided on a lower surface 29b of the second sandwiching portion 29. This makes it possible to protect the first outer layer 61 and the second outer layer 62 of the printed circuit board 20, and increases the strength of the printed circuit board 20 in the thickness direction.

[0042] In addition, the case 30 is made of aluminum die casting, and the cover 40 is made of sheet metal, so that the second sandwiching portion 29 of the printed circuit board 20 can serve as a frame ground for the circuit.

[0043] 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, in the second sandwiching portion 29 of the printed circuit board 20, the first outer layer 61 and the second outer layer 62 are more easily deformed than the first inner layer 63 to the third inner layer 65. Since the force generated by being sandwiched between the cover side support portion 44 and the case side support portion 37 can be dispersed to the entire printed circuit board 20, the stress generated in the soldered portions of the electronic components arranged around the second sandwiching portion 29 can be reduced.

[0044] In addition, refer to Fig. 2. A first long edge 24 of the printed circuit board 20 is supported by two first case side supporting parts 36 and two first cover side supporting parts 43. A second long edge 25 of the printed circuit board 20 is supported by two first case side supporting parts 36 and two first cover side supporting parts 43. Since both ends 24, 25 of the printed circuit board 20 are supported, the printed circuit board 20 can be reliably fixed to the case 30. Note that instead of a configuration in which the long edges 24, 25 are supported, the short edges 26, 27 may be supported.

[0045] The above-mentioned effects of the invention are also exhibited in the second embodiment described below.

[0046] <Example 2> Fig. 5 shows an electronic control device 10A according to embodiment 2. Configurations common to the electronic control device 10 (see Fig. 4) of embodiment 1 are given the same reference numerals as in embodiment 1, and descriptions thereof will be omitted.

[0047] The holes 50a of the respective through vias 50 are filled with a filling member 80 (e.g., a resin material). A first copper-plated portion 91 that is copper-plated is provided on the upper surface 29a of the second sandwiching portion 29. The first copper-plated portion 91 covers the through vias 50 and the filling member 80. The first copper-plated portion 91 is in contact with the lower surface 44a of the second cover side support portion 44.

[0048] A second copper-plated portion 92, which is copper-plated, is provided on the lower surface 29b of the second sandwiching portion 29. The second copper-plated portion 92 covers the through vias 50 and the filling member 80. The first copper-plated portion 91 is in contact with the upper surface 37a of the second case side support portion 37. The material for plating is not limited to copper, and any metal suitable for plating can be selected. It is also possible to have a configuration in which only either the first copper-plated portion 91 or the second copper-plated portion 92 is provided.

[0049] (Effects of Example 2) Since the hole 50a of the through via 50 is filled with the filling member 80, the through via 50 can be reinforced, and the strength of the second sandwiching portion 29 in the thickness direction is increased.

[0050] Furthermore, a first copper-plated portion 91, which is copper-plated, is provided on an upper surface 29a of the second sandwiching portion 29. A second copper-plated portion 92, which is copper-plated, is provided on a lower surface 29b of the second sandwiching portion 29. These first and second plated portions cover the through vias 50 and the filling member 80. Therefore, the contact areas of the first and second plated portions with the case 30 and the cover 40 are increased, and the heat dissipation effect is improved.

[0051] As long as the functions and effects of the present invention are achieved, the present invention is not limited to the examples. [Industrial Applicability]

[0052] The electronic control device of the present invention is suitable for four-wheeled vehicles. [Explanation of symbols]

[0053] 10...Electronic control device 20...Printed circuit board 24...First long edge (edge ​​of printed circuit board) 25...Second long edge (edge ​​of printed circuit board) 29… Clamping part 30…Case 31…Case opening 36…First case side support part 37…Second case side support part 40…Cover 43...First cover side support part 44…Second cover side support part 45…Outer edge of cover 50…Through via 61...First outer layer (outermost layer) 62…Second outer layer (outermost layer) 63…First inner layer (adjacent layer) 64…Second inner layer (adjacent layer) 71…1st copper foil 72…Second copper foil 80...Filling material 91…1st plating section 92…2nd plating section

Claims

1. a case having an opening and housing a printed circuit board therein; a cover closing the opening of the case, The outer periphery of the cover is overlapped with and fixed to the edge of the opening of the case, the case has a case-side contact surface that is in contact with an end of the printed circuit board on the inner side of the edge of the opening of the case, the cover has a cover-side contact surface that is in contact with the end of the printed circuit board and thereby sandwiches the end of the printed circuit board together with the case-side contact surface, An electronic control device, wherein a through via is provided in a sandwiched portion of the printed circuit board that is sandwiched between the case side contact surface and the cover side contact surface.

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

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

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

5. The case-side contact surface and the cover-side contact surface are each provided in a plurality of surfaces, The electronic control device according to any one of claims 1 to 4, wherein the plurality of case side contact surfaces and the cover side contact surfaces are arranged along a pair of edges extending in the same direction within the printed circuit board.

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