Electronic control device

Abstract

This electronic control device comprises: a liquid cooling unit; a first circuit board and a second circuit board mounted on one side and the other side of the liquid cooling unit; and a sheet-shaped transmission member electrically connecting the first circuit board and the second circuit board. The liquid cooling unit has an insertion hole for inserting the sheet-shaped transmission member.

Description

Electronic control unit

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

[0002] Electronic control units (ECUs) installed in vehicles require high computing power to realize driver assistance systems such as collision mitigation braking and autonomous driving. To this end, automotive ECUs incorporate integrated circuits with high operating frequencies. As a result, the amount of high-frequency electromagnetic noise emitted by ECUs tends to increase. Given this situation, it is necessary to suppress this noise below the standard values ​​set by national laws. Furthermore, to achieve high integration in ECUs, there is a growing need for a configuration in which two circuit boards, each with electronic components mounted on them, are electrically connected.

[0003] Patent Document 1 describes an electronic control device in which a hollow cylindrical partition member through which a cooling medium (oil) flows is placed between two circuit boards, and the two circuit boards are electrically connected by a board-to-board connector (BtoB connector).

[0004] JP 2011-171163 A

[0005] However, in the electronic control device described in Patent Document 1, the separating beam member disposed between two circuit boards is divided into two, and the board-to-board connector is disposed in the space provided between the two separating beam members. This has the disadvantage of making it easier for noise to propagate between the two circuit boards. Furthermore, the presence of the space limits the size of the separating beam member, which in turn reduces cooling efficiency.

[0006] An object of the present invention is to provide an electronic control device that can suppress the propagation of noise between two circuit boards and achieve high cooling efficiency.

[0007] To solve the above problems, for example, the configurations described in the claims are adopted. The present application includes multiple means for solving the above problems, one of which is an electronic control device including a liquid cooling unit having a first main surface and a second main surface, a first circuit board mounted on the first main surface of the liquid cooling unit, a second circuit board mounted on the second main surface of the liquid cooling unit, and a sheet-like transmission member electrically connecting the first circuit board and the second circuit board. The liquid cooling unit has an insertion hole for inserting the sheet-like transmission member.

[0008] According to the present invention, it is possible to suppress the propagation of noise between two circuit boards and achieve high cooling efficiency. Objects, configurations, and effects other than those described above will become clear from the description of the following embodiments.

[0009] 1 is a perspective view showing an example of the configuration of an electronic control device according to an embodiment; FIG. 2 is a cross-sectional view of the electronic control device shown in FIG. 1 taken along line II-II; FIG. 3 is an exploded view of the electronic control device shown in FIG. 1; FIG. 4 is a cross-sectional view of the sheet-shaped transmission member included in the electronic control device according to an embodiment, viewed from the front; FIG. 5 is a cross-sectional view of the sheet-shaped transmission member shown in FIG. 4 taken along line V-V; FIG. 6 is a partial plan view of a liquid cooling unit included in the electronic control device according to an embodiment, viewed from the first circuit board side; FIG. 7 is a diagram (part 1) illustrating an example of an assembly procedure for the electronic control device according to an embodiment; FIG. 8 is a diagram (part 2) illustrating an example of an assembly procedure for the electronic control device according to an embodiment; FIG. 9 is a diagram (part 3) illustrating an example of an assembly procedure for the electronic control device according to an embodiment; FIG. 10 is a diagram (part 4) illustrating an example of an assembly procedure for the electronic control device according to an embodiment; FIG. 11 is a diagram (part 5) illustrating an example of an assembly procedure for the electronic control device according to an embodiment; and FIG. 12 is a diagram illustrating an arrangement of insertion holes in the liquid cooling unit and the sheet-shaped transmission member.

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, elements having substantially the same function or configuration are designated by the same reference numerals, and redundant description will be omitted as appropriate. Furthermore, the following description and drawings are illustrative of the present invention and may be omitted or simplified for the sake of convenience. Each component may be singular or plural unless otherwise specified. Furthermore, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc., disclosed in the drawings.

[0011] Fig. 1 is a perspective view showing an example of the configuration of an electronic control device according to an embodiment. Fig. 2 is a cross-sectional view of the electronic control device shown in Fig. 1 taken along line II-II. Fig. 3 is an exploded view of the electronic control device shown in Fig. 1. In the following description, in order to clarify the shapes and positional relationships of the various parts of the electronic control device, the height direction (thickness direction) of the electronic control device is defined as the Z-axis direction, and one of two axial directions perpendicular to the Z-axis direction is defined as the X-axis direction, and the other is defined as the Y-axis direction.

[0012] 1 to 3, an electronic control device 10 according to this embodiment includes a housing base 11, a housing cover 12, a liquid cooling unit 13, a first circuit board 14, a second circuit board 15, and a sheet-like transmission member 16. The first circuit board 14 corresponds to a daughter board, and the second circuit board 15 corresponds to a mother board. The first circuit board 14 is attached to the liquid cooling unit 13 using first board mounting screws 17, and the second circuit board 15 is attached to the liquid cooling unit 13 using second board mounting screws 18. The electronic control device 10 is an in-vehicle electronic control device used, for example, in autonomous driving and driving assistance systems.

[0013] The housing of the electronic control unit 10 is composed of a housing base 11 and a housing cover 12. The electronic control unit 10 is preferably mounted on a vehicle with the housing base 11 facing upward and the housing cover 12 facing downward. Both the housing base 11 and the housing cover 12 are formed in a quadrilateral shape (including a rectangle, a square, etc.) in a plan view.

[0014] The housing base 11 and the housing cover 12 are arranged to sandwich the liquid cooling unit 13. A first board storage space is formed between the housing base 11 and the liquid cooling unit 13, and a first circuit board 14 is stored in the first board storage space. A second board storage space is formed between the housing cover 12 and the liquid cooling unit 13, and a second circuit board 15 is stored in the second board storage space.

[0015] The liquid cooling unit 13 is a casting made of, for example, aluminum (including aluminum alloy) and is formed in a rectangular shape in plan view, similar to the above-described housing. The liquid cooling unit 13 has a first main surface 13a and a second main surface 13b. A flow path (not shown) for flowing a liquid refrigerant (cooling water, cooling oil, etc.) is formed inside the liquid cooling unit 13. In addition, a first protrusion 21 is provided on the first main surface 13a, and a second protrusion 22 is provided on the second main surface 13b. Both the first protrusion 21 and the second protrusion 22 are formed integrally with the liquid cooling unit 13.

[0016] The first circuit board 14 is formed of a rigid printed wiring board made of, for example, glass epoxy as a base material. The first circuit board 14 is mounted on the first main surface 13a of the liquid cooling unit 13. More specifically, first screw insertion holes (not shown) are provided in the four corners of the first circuit board 14, and first screw holes (not shown) are provided on the first main surface 13a of the liquid cooling unit 13 in the same positional relationship as the first screw insertion holes. The first circuit board 14 is fixedly attached to the first main surface 13a of the liquid cooling unit 13 by inserting first board mounting screws 17 into the first screw insertion holes, engaging them with the first screw holes of the liquid cooling unit 13, and then tightening the first board mounting screws 17.

[0017] A first electronic component 24 is mounted on the first circuit board 14. The first electronic component 24 is an electronic component (heat-generating component) that generates a large amount of heat per unit time, such as a semiconductor element such as a CPU, MPU, or GPU with a high operating frequency, or a power semiconductor. The first electronic component 24 is thermally connected to the first protrusion 21 of the liquid cooling unit 13, preferably via a thermally conductive adhesive, thermally conductive grease, or thermally conductive sheet (not shown). The number of first protrusions 21 and first electronic components 24 can be changed as desired. A first connector 25 is also mounted on the first circuit board 14. The first connector 25 has a socket (not shown) formed therein. This socket is formed in the shape of a long slit in the Y-axis direction.

[0018] The second circuit board 15 is configured as a rigid printed wiring board made of, for example, glass epoxy. The second circuit board 15 is mounted on the second main surface 13b of the liquid cooling unit 13. More specifically, second screw insertion holes (not shown) are provided in the four corners of the second circuit board 15, and second screw holes (not shown) are provided on the second main surface 13b of the liquid cooling unit 13 in the same positional relationship as the second screw insertion holes. The second circuit board 15 is fixedly attached to the second main surface 13b of the liquid cooling unit 13 by inserting second board mounting screws 18 into the second screw insertion holes, engaging them with the second screw holes of the liquid cooling unit 13, and then tightening the second board mounting screws 18.

[0019] A second electronic component 27 is mounted on the second circuit board 15. The second electronic component 27 is an electronic component (heat-generating component) that generates a large amount of heat per unit time, such as a semiconductor element (e.g., a CPU, MPU, or GPU) with a high operating frequency, or a power semiconductor. The second electronic component 27 is thermally connected to the second protrusion 22 of the liquid cooling unit 13, preferably via a thermally conductive adhesive, thermally conductive grease, or thermally conductive sheet (not shown). The number of second protrusions 22 and second electronic components 27 can be changed as desired. A second connector 28 and an external connection connector 29 are also mounted on the second circuit board 15. The second connector 28 has a socket (not shown). This socket is formed with a slit-like elongated shape in the Y-axis direction. The external connection connector 29 is a connector for connecting the electronic control device 10 to external devices.

[0020] The sheet-like transmission member 16 is a thin member that electrically connects the first circuit board 14 and the second circuit board 15. The sheet-like transmission member 16 is also a member that transmits electrical signals between the first circuit board 14 and the second circuit board 15. The sheet-like transmission member 16 is formed, for example, by a flexible printed wiring board. The thickness of the sheet-like transmission member 16 is, for example, not less than 60 μm and not more than 100 μm.

[0021] As shown in FIG. 3 , the sheet-like transmission member 16 has a first insertion portion 16 a and a second insertion portion 16 b. The first insertion portion 16 a is inserted into the insertion port of the first connector 25 described above. The first insertion portion 16 a and the first connector 25 each have a plurality of connection terminal portions in a predetermined arrangement. By inserting the first insertion portion 16 a into the insertion port of the first connector 25, the corresponding connection terminal portions are electrically and mechanically connected to each other. The second insertion portion 16 b is inserted into the insertion port of the second connector 28 described above. The second insertion portion 16 b and the second connector 28 each have a plurality of connection terminal portions in a predetermined arrangement. By inserting the second insertion portion 16 b into the insertion port of the second connector 28, the corresponding connection terminal portions are electrically and mechanically connected to each other.

[0022] A reinforcing plate 30 is attached to the sheet-like transmission member 16. The reinforcing plate 30 is a member for increasing the rigidity of the sheet-like transmission member 16. The reinforcing plate 30 is made of an insulating plate such as polyimide, PET (polyethylene terephthalate), or glass epoxy, having a thickness (e.g., 0.2 mm to 0.3 mm) greater than that of the sheet-like transmission member 16. The reinforcing plate 30 is attached to the entire surface of one side of the sheet-like transmission member 16 except for the first insertion portion 16a and the second insertion portion 16b. The length of the reinforcing plate 30 is set appropriately according to the length (dimension in the Z-axis direction) of the sheet-like transmission member 16. The reinforcing plate 30 is a member that is provided as needed.

[0023] Fig. 4 is a view of the sheet-like transmission member provided in the electronic control device according to the embodiment, as seen from the front (X-axis direction). Fig. 5 is a cross-sectional view of the sheet-like transmission member shown in Fig. 4 taken along line V-V. In Figs. 4 and 5, the X-axis direction corresponds to the thickness direction of the sheet-like transmission member 16, the Y-axis direction corresponds to the width direction of the sheet-like transmission member 16, and the Z-axis direction corresponds to the length direction of the sheet-like transmission member 16.

[0024] As shown in Figures 4 and 5, the sheet-like transmission member 16 has two ground wires 35 and six signal wires 36. The two ground wires 35 are formed at both ends of the sheet-like transmission member 16 in the width direction (Y-axis direction). The six signal wires 36 are formed between the two ground wires 35. The ground wires 35 and the signal wires 36 are formed parallel to each other along the length direction of the sheet-like transmission member 16. One end of the ground wire 35 in the length direction is disposed in the first insertion portion 16a, and the other end of the ground wire 35 in the length direction is disposed in the second insertion portion 16b. Similarly, one end of the signal wire 36 in the length direction is disposed in the first insertion portion 16a, and the other end of the signal wire 36 in the length direction is disposed in the second insertion portion 16b.

[0025] The number of ground wirings 35 is not limited to two, but may be three or more. The number of signal wirings 36 can be changed as desired. The ground wirings 35 and signal wirings 36 are not limited to being arranged in a single row, but may be arranged in multiple rows.

[0026] On the other hand, the liquid cooling unit 13 is provided with an insertion hole 31 for inserting the sheet-like transmission member 16. The insertion hole 31 is provided in a state of penetrating the liquid cooling unit 13 from the first main surface 13a to the second main surface 13b.

[0027] 6 is a partial plan view of a liquid cooling unit included in an electronic control device according to an embodiment, viewed from the first circuit board side. In FIG. 6, the dimension L2 of the insertion hole 31 in the Y-axis direction is set slightly larger than the dimension L1 ( FIG. 5 ) of the sheet-like transmission member 16 in the Y-axis direction. Furthermore, both ends of the insertion hole 31 in the Y-axis direction are narrower than the remaining portions of the insertion hole 31 (in other words, the portions closer to the center of the insertion hole 31). Specifically, the dimension W1 of both ends of the insertion hole 31 in the Y-axis direction is set narrower than the dimension W2 of the remaining portions of the insertion hole 31.

[0028] The dimensions W1 and W2 are both dimensions of the insertion hole 31 defined in the X-axis direction. Furthermore, the dimension W1 is the dimension between two inner surfaces 31a of the insertion hole 31 that face each other in the X-axis direction, and the dimension W2 is the dimension between two inner surfaces 31b that face each other in the X-axis direction. When the reinforcing plate 30 is attached to the sheet-like transmission member 16, the dimension W1 is set to be slightly larger than the thickness of the sheet-like transmission member 16 and the reinforcing plate 30 that are laminated together. When the reinforcing plate 30 is not attached to the sheet-like transmission member 16, the dimension W1 is set to be slightly larger than the thickness of the sheet-like transmission member 16.

[0029] A tapered portion 37 is formed at one end of the insertion hole 31 in the depth direction (Z-axis direction). The tapered portion 37 is formed at a position facing the first circuit board 14. The tapered portion 37 is formed to open outward so that the opening dimensions of the insertion hole 31 gradually increase as it approaches the first circuit board 14. The tapered portion 37 is formed to guide the sheet-like transmission member 16 into the insertion hole 31.

[0030] When assembling the electronic control device 10 configured as described above, first, as shown in Fig. 7, the first insertion portion 16a of the sheet-like transmission member 16 is inserted in the direction of the arrow into the first connector 25 of the first circuit board 14. As a result, the first insertion portion 16a is connected to the first connector 25 by snap-in or press-fitting. In addition, the ground wiring 35 and signal wiring 36 formed on the sheet-like transmission member 16 as shown in Fig. 4 are electrically connected to the corresponding connection terminal portions of the first connector 25.

[0031] 8, the sheet-like transmission member 16 is inserted in the direction of the arrow into the insertion hole 31 of the liquid cooling unit 13. At this time, the sheet-like transmission member 16 is guided by the tapered portion 37 and led into the insertion hole 31. Therefore, the assembly workability can be improved compared to when the tapered portion 37 is not provided.

[0032] Next, as shown in Fig. 9, the sheet-like transmission member 16 is inserted into the insertion hole 31 of the liquid cooling unit 13. In this embodiment, since both end portions of the insertion hole 31 are narrowed as shown in Fig. 6, when the sheet-like transmission member 16 is inserted into the insertion hole 31, the narrowed portion (the inner surface 31a of the insertion hole 31) serves as a guide portion, allowing the sheet-like transmission member 16 to be smoothly inserted into the insertion hole 31.

[0033] Next, as shown in FIGS. 10 and 11 , the second insertion portion 16 b of the sheet-like transmission member 16 is inserted into the second connector 28 of the second circuit board 15. At this time, deformation such as warping and bending of the sheet-like transmission member 16 is suppressed by the reinforcing plate 30. Therefore, the insertion force applied to the sheet-like transmission member 16 via the first circuit board 14 is transmitted to the second insertion portion 16 b by the reinforcing effect of the reinforcing plate 30. Therefore, the second insertion portion 16 b can be connected to the second connector 28 by snap-in or press-fit. As a result, the ground wiring 35 and signal wiring 36 formed on the sheet-like transmission member 16 as shown in FIG. 4 are electrically connected to the corresponding connection terminal portions of the second connector 28. Furthermore, the first circuit board 14 and the second circuit board 15 are electrically connected via the sheet-like transmission member 16.

[0034] In this manner, when the first circuit board 14 and the second circuit board 15 are electrically connected by the sheet-like transmission member 16, as shown in FIG. 12 , the clearance C1 between the ground wiring 35 and the signal wiring 36 formed on the sheet-like transmission member 16 and the inner surface 31a of the insertion hole 31 is narrower than the clearance C2 between the signal wiring 36 and the inner surface 31b of the insertion hole 31. As a result, the ground wiring 35 is capacitively coupled to the liquid cooling unit 13 via the insulating layer of the sheet-like transmission member 16 and the clearance C1. This strengthens the ground wiring 35. Meanwhile, the signal wiring 36 has a lower degree of capacitive coupling with the liquid cooling unit 13 due to the presence of the clearance C2, which is wider than the clearance C1. This prevents deterioration of signal integrity (SI). Note that the reinforcing plate 30 is not shown in FIG. 12 .

[0035] In the electronic control device 10 according to this embodiment, the first circuit board 14 and the second circuit board 15 are electrically connected by a sheet-like transmission member 16, and the sheet-like transmission member 16 is inserted into the insertion hole 31 of the liquid cooling unit 13. This configuration allows the size of the insertion hole 31, which serves as a noise propagation path, to be smaller than when the first circuit board 14 and the second circuit board 15 are electrically connected by a board-to-board connector (not shown). This reduces the propagation of noise between the first circuit board 14 and the second circuit board 15. Furthermore, the smaller size of the insertion hole 31 as described above allows the liquid cooling unit 13 to be larger, achieving high cooling efficiency.

[0036] The technical scope of the present invention is not limited to the above-described embodiments, but also includes forms in which various modifications and improvements are made within the scope that can derive specific effects obtained by the constituent elements of the invention and their combinations.

[0037] For example, in the above embodiment, a flexible printed wiring board is given as an example of the sheet-like transmission member, but the sheet-like transmission member is not limited to this, and may be configured, for example, by a flat cable, etc. Furthermore, the sheet-like transmission member may be configured by a rigid printed wiring board having a thickness equivalent to that of the flexible printed wiring board or the flat cable.

[0038] Furthermore, in the above embodiment, when forming the tapered portion 37 in the insertion hole 31, the tapered portion 37 is formed on the upper surface side of the liquid cooling unit 13 in Figure 2, but this is not limited to this, and the tapered portion may also be formed on the lower surface side of the liquid cooling unit 13.

[0039] 10...Electronic control device, 13...Liquid cooling unit, 13a...First main surface, 13b...Second main surface, 14...First circuit board, 15...Second circuit board, 16...Sheet-like transmission member, 30...Reinforcing plate, 31...Through-hole, 31a, 31b...Inner surface, 35...Ground wiring, 36...Signal wiring, 37...Tapered portion 37

Claims

1. An electronic control device comprising: a liquid cooling unit having a first main surface and a second main surface; a first circuit board mounted on the first main surface side of the liquid cooling unit; a second circuit board mounted on the second main surface side of the liquid cooling unit; and a sheet-like transmission member electrically connecting the first circuit board and the second circuit board, wherein the liquid cooling unit has an insertion hole for inserting the sheet-like transmission member.

2. The electronic control device according to claim 1, wherein the sheet-like transmission member has at least two ground wirings formed on both ends of the sheet-like transmission member in the width direction and a signal wiring formed between the two ground wirings, and the clearance between the formation portion of the ground wiring and the inner surface of the insertion hole is narrower than the clearance between the formation portion of the signal wiring and the inner surface of the insertion hole.

3. The electronic control device according to claim 1, wherein a reinforcing plate is attached to the sheet-like transmission member.

4. The electronic control device according to claim 1, wherein an outwardly opening tapered portion is formed at one end of the insertion hole in the depth direction.

5. The electronic control device according to claim 1, wherein both ends of the insertion hole in the width direction of the sheet-like transmission member are formed narrower than other portions of the insertion hole.

Images