Electronic control unit

Abstract

This electronic control device is provided with: a circuit board which comprises a wiring board that is provided with a wiring pattern including a high-speed signal line, and an electronic component that is mounted on a first surface of the wiring board and is connected to the high-speed signal line; a case in which the circuit board is housed; and a first heat transfer member which is in contact with the electronic component and the case. The first heat transfer member is disposed so as to extend from the upper surface of the electronic component to the case, while being disposed so as to extend from the first surface of the wiring board to the case and so as to be in contact with a part of the outer peripheral surface of the electronic component at a position where the first heat transfer member is not on the high-speed signal line.

Description

[Technical Field]

[0001] The present invention relates to an electronic control device, and more particularly to an electronic control device that houses a circuit board in a housing. [Background technology]

[0002] Generally, vehicles such as automobiles are equipped with multiple electronic control units. An electronic control unit installed in a vehicle (hereinafter sometimes referred to as an in-vehicle electronic control unit) has a structure in which a circuit board on which electronic components are mounted is housed inside a housing.

[0003] In recent years, the functionality of in-vehicle electronic control devices, including electronic control devices for autonomous driving and advanced driver assistance systems, has been increasing, and the amount of heat generated by electronic components is on the rise. If the temperature of an electronic component rises above its rated temperature and its function deteriorates, this may lead to malfunction of the electronic control device. Therefore, in order to suppress the temperature rise caused by heat generated by electronic components, a known method is to use a thermal interface material (TIM) such as thermal grease to dissipate heat from the electronic component into the housing (see, for example, Patent Document 1).

[0004] The electronic control device described in Patent Document 1 is configured to transfer heat generated by electronic components (for example, power MOSFETs as semiconductor elements) to the case by filling a heat dissipation gel (TIM) between the mounting surface of a board on which the electronic components are mounted and the opposing surface of the case facing the mounting surface (see, for example, Figure 18 of Patent Document 1). That is, the heat dissipation gel is filled so as to completely cover the entire outer surface (top surface and all sides) of the electronic components mounted on the board. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-023593 Summary of the Invention [Problem to be solved by the invention]

[0006] In electronic control devices for autonomous driving and advanced driver assistance systems, heat-generating electronic components are often high-performance components that operate at high speeds, such as SoCs (System-on-Chips) with a BGA (Ball Grid Array) package structure. Such high-performance electronic components are often electrically connected to high-speed signal lines. In this specification, electronic components that operate at operating frequencies higher than 100 MHz are defined as electronic components capable of high-speed operation, and signal lines for transmitting signals at frequencies higher than 100 MHz are defined as high-speed signal lines.

[0007] Consider the case where the technology described in Patent Document 1 is applied to a high-performance electronic component capable of high-speed operation to enhance heat dissipation. In this case, a TIM is disposed to cover the entire outer surface (top and side surfaces) of the electronic component connected to a high-speed signal line on a circuit board, raising concerns about a deterioration in the quality of high-frequency signals transmitted through the high-speed signal line and an increase in radiated noise. This is because the TIM covering the electronic component is disposed between the high-speed signal line on the circuit board and the case, increasing the capacitance between the high-speed signal line and the case due to the TIM. This increase in capacitance causes a deterioration in the quality of high-frequency signals and an increase in radiated noise. If the quality of high-frequency signals decreases and the radiated noise increases, there is a concern that the high functionality of the automotive electronic control unit will decrease.

[0008] In the technology described in Patent Document 1, a power MOSFET is cited as an example of a heat-generating electronic component mounted on a substrate. Power MOSFETs generally operate at frequencies lower than 100 MHz, which is considered the high-speed operation in this description. Therefore, there is little need to consider the above-mentioned problems of a reduction in high-frequency signal quality and an increase in radiation noise due to the placement of a TIM to improve the heat dissipation of electronic components.

[0009] The present invention has been made to solve the above problems, and its purpose is to provide an electronic control device that can ensure the quality of high-frequency signals and suppress radiated noise while maintaining heat dissipation. [Means for solving the problem]

[0010] The present application includes multiple means for solving the above-mentioned problems. For example, an electronic control device includes: a circuit board having a wiring board on which a wiring pattern including a high-speed signal line is formed and an electronic component mounted on a first surface of the wiring board and electrically connected to the high-speed signal line; a housing that houses the circuit board; and a first heat conductive member that directly contacts the electronic component and the housing, wherein the electronic component has a bottom surface facing the first surface of the wiring board, a top surface located opposite the bottom surface, and an outer circumferential surface that connects to an outer edge of the bottom surface and an outer circumferential surface of the top surface, and the first heat conductive member is disposed to extend from the top surface of the electronic component to the housing and to contact a portion of the outer circumferential surface of the electronic component at a position that avoids the high-speed signal line. [Effects of the Invention]

[0011] According to the present invention, by arranging the first heat conduction member so that it contacts a portion of the upper surface and outer peripheral surface of the electronic component, heat dissipation is maintained, and by arranging the first heat conduction member at a position that avoids high-speed signal lines, an increase in capacitance between the high-speed signal lines and the housing due to the arrangement of the first heat conduction member can be avoided. This makes it possible to ensure the quality of high-frequency signals and suppress radiation noise while maintaining heat dissipation. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic perspective view showing an electronic control device according to an embodiment of the present invention in an exploded state; [Figure 2]2 is a schematic cross-sectional view showing electronic components on a circuit board and the surrounding structure in the electronic control device according to the first embodiment. FIG. [Figure 3] 2 is a schematic top view showing electronic components on a circuit board and the surrounding structure of the electronic control device according to the first embodiment. FIG. [Figure 4] 4 is a schematic perspective view showing electronic components and their peripheral structure on a circuit board of the electronic control device according to the first embodiment shown in FIG. 3. FIG. [Figure 5] 3 is a schematic top view showing electronic components on a circuit board and their surrounding structure in an electronic control device that is a comparative example to the electronic control device according to the first embodiment. FIG. [Figure 6] 10 is a schematic cross-sectional view (a cross section taken along the top surface of the electronic component) showing the arrangement of a TIM that contacts a side surface of an electronic component on a circuit board in an electronic control device according to a first modified example of the first embodiment. [Figure 7] 10 is a schematic cross-sectional view (a cross section taken along the top surface of the electronic component) showing the arrangement of a TIM that contacts a side surface of an electronic component on a circuit board in an electronic control device according to a second modified example of the first embodiment. [Figure 8] 10 is a schematic cross-sectional view (a cross section taken along the top surface of the electronic component) showing the arrangement of a TIM that contacts a side surface of an electronic component on a circuit board in an electronic control device according to a third modified example of the first embodiment. FIG. [Figure 9] FIG. 10 is a perspective view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a schematic bottom view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to a second embodiment. [Figure 11] FIG. 10 is a perspective view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to a first example of a first modified example of the second embodiment. [Figure 12] FIG. 10 is a perspective view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to a second example of the first modified example of the second embodiment. [Figure 13]FIG. 10 is a cross-sectional view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to a first example of a second modified example of the second embodiment. [Figure 14] FIG. 10 is a cross-sectional view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to a second example of a second modified example of the second embodiment. [Figure 15] 10 is a schematic diagram showing the positional relationship between electronic components and heat conduction paths (through holes) on a circuit board in an electronic control device according to a first example of a third modified example of the second embodiment. FIG. [Figure 16] 10 is a schematic diagram showing the positional relationship between electronic components and heat conduction paths (through holes) on a circuit board in an electronic control device according to a second example of a third modified example of the second embodiment. FIG. [Figure 17] FIG. 10 is a contour diagram showing the heat flow rate of a circuit board in an electronic control device according to a first example of a third modified example of the second embodiment. [Figure 18] FIG. 10 is a schematic cross-sectional view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to a third embodiment of the present invention. [Figure 19] FIG. 10 is a schematic perspective view showing the appearance of an electronic control device according to a fourth embodiment of the present invention. [Figure 20] FIG. 10 is a schematic perspective view showing the appearance of an electronic control device according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of an electronic control device of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functions or configurations are designated by the same reference numerals, and redundant description will be omitted.

[0014] [First embodiment] First, the configuration and structure of an electronic control device according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic perspective view showing an electronic control device according to the embodiment in an exploded state.

[0015] In Fig. 1, an electronic control unit 1 according to this embodiment is a control unit that performs high-speed communication. The electronic control unit 1 is mounted on, for example, a vehicle (not shown) and used as a control unit that controls or assists vehicle driving. The electronic control unit 1 can also be used as a control unit for millimeter-wave radar, an in-vehicle camera, etc. The control target of the electronic control unit 1 is not limited to a specific object.

[0016] The electronic control device 1 includes a circuit board 2 that forms an electronic circuit, and a housing 3 that houses the circuit board 2.

[0017] The circuit board 2 includes a printed wiring board 11 on which a wiring pattern (not shown) including a high-speed signal line 12 (see FIG. 3 ) is formed, and a plurality of electronic components 14 mounted on the printed wiring board 11. The printed wiring board 11 has a first surface 11a and a second surface 11b on which electronic components can be mounted. The printed wiring board 11 can be configured as either a single-sided board in which a wiring pattern is formed on only one of the first surface 11a and the second surface 11b, or a double-sided board in which a wiring pattern is formed on both surfaces. The printed wiring board 11 is configured, for example, as a rigid board using glass epoxy as a base material. The electronic components 14 include, for example, various elements such as resistors, capacitors, diodes, memory elements, and switching elements, as well as connectors 15, and heat-generating electronic components 16 that require heat dissipation measures. In the circuit board 2 shown in FIG. 1, the heat-generating electronic components 16 are mounted on the first surface 11a of the printed wiring board 11. That is, the first surface 11a of the printed wiring board 11 is the mounting surface for the electronic components 16 that generate heat.

[0018] The heat-generating electronic component 16 in this embodiment is an electronic component capable of operating at a high operating frequency of several hundred MHz to several GHz. Electronic components 16 capable of high-speed operation (hereinafter sometimes referred to as high-speed electronic components) consume very high power consumption due to high-speed processing, sometimes reaching tens of watts, and generate a lot of heat. The high-speed electronic component 16 is, for example, a microcontroller incorporating a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a highly functional component such as an IC (Integrated Circuit) chip or a semiconductor chip. The highly functional electronic component 16 is capable of high-speed communication with various electronic components, such as a DDR memory or a SERializer with a signal conversion function. The high-speed electronic component 16 also includes, for example, a high-speed memory capable of high-speed communication with a microcontroller including the above-mentioned processor via a high-speed communication line. Since high-speed electronic components 16 generate a lot of heat, heat dissipation measures are necessary. The specific configuration of the high-speed electronic component 16 will be described later.

[0019] The housing 3 is composed of, for example, a case body 21 that forms an internal space for accommodating the circuit board 2, and a cover 22 that closes an opening in the case body 21 for inserting the circuit board 2. The case body 21 has an opposing surface 21a (see FIG. 2 described later) that faces the first surface 11a (the surface on which the electronic components 16 are mounted) of the printed wiring board 11. The cover 22 is disposed so as to face the second surface 11b of the printed wiring board 11. The case body 21 and the cover 22 are formed of, for example, a metal material from the viewpoint of heat dissipation. The case body 21 and the cover 22, when the circuit board 2 is accommodated therein, are joined by a plurality of screws 23.

[0020] Next, the configuration of high-speed electronic components and the heat dissipation structure for the high-speed electronic components in the electronic control device according to the first embodiment will be described with reference to Figures 2 to 4. Figure 2 is a schematic cross-sectional view showing the electronic components and their peripheral structure on the circuit board in the electronic control device according to the first embodiment. Figure 3 is a schematic top view showing the electronic components and their peripheral structure on the circuit board in the electronic control device according to the first embodiment. Figure 4 is a schematic perspective view showing the electronic components and their peripheral structure on the circuit board of the electronic control device according to the first embodiment shown in Figure 3.

[0021] As shown in FIG. 2, the electronic component 16 capable of high-speed operation includes an IC chip 32 as a heat source embedded in a semiconductor package with a BGA (Ball Grid Array) structure. More specifically, the electronic component 16 includes the IC chip 32 disposed on a substrate 31, solder balls 33 that electrically connect the IC chip 32 to a wiring pattern on the circuit board 2, a lid 34 that covers and protects the IC chip 32, and a sealing resin 35 that fills the inside of the lid 34 and seals the IC chip 32. The electronic component 16 is formed in a flat rectangular parallelepiped shape and has a rectangular shape when viewed from the top surface 16b (described later). The outer surfaces of the high-speed electronic component 16 include a bottom surface 16a on the solder ball 33 side that faces the first surface 11a of the printed wiring board 11, a top surface 16b located opposite the bottom surface 16a, and an outer peripheral surface 16c that connects the outer edges of the bottom surface 16a and the top surface 16b. An upper surface 16b of the electronic component 16 faces an opposing surface 21a of the case body 21 of the housing 3. An outer peripheral surface 16c of the electronic component 16 is made up of four side surfaces.

[0022] As shown in Figures 3 and 4, the high-speed processing electronic component 16 is connected to a high-speed signal line 12 (part of the wiring pattern) on the printed wiring board 11. The high-speed signal line 12 is configured as a signal line capable of transmitting high-frequency signals of several hundred MHz to several GHz. The high-speed signal line 12 extends, for example, from two of the four side surfaces 16c of the electronic component 16 that are located opposite each other. More specifically, the high-speed signal line 12 extends from an area near a corner of the side surface 16c of the electronic component 16.

[0023] The high-speed electronic component 16 requires heat dissipation measures because the IC chip 32 generates heat due to high-speed operation. Therefore, as shown in FIGS. 2 to 4, the outer surface of the high-speed electronic component 16 is thermally connected to the case body 21 of the housing 3 via a heat conductive member 40. That is, the heat conductive member 40 is thermally connected to the electronic component 16 by directly contacting the case body 21, and has the function of transferring heat generated by the electronic component 16 to the case body 21. The heat conductive member 40 is made of a resin to which a thermally conductive filler has been added. For example, a TIM (Thermal Interface Material) such as a thermal grease or a thermally conductive sheet made primarily of silicone, acrylic, epoxy, or urethane resin is used as the heat conductive member 40.

[0024] 3 and 4, the heat conduction member 40 in this embodiment is disposed so as to contact a portion of the top surface 16b and the side surfaces 16c of the outer surface of the electronic component 16 at a position that avoids the space above the high-speed signal line 12 of the printed wiring board 11. Specifically, the heat conduction member 40 has, for example, a top surface conductive portion 41 disposed so as to extend from the top surface 16b of the electronic component 16 to the opposing surface 21a of the case body 21, and four side surface conductive portions 42 disposed so as to extend from the printed wiring board 11 to the opposing surface 21a of the case body 21 while contacting a central portion (a portion) of each of the four side surfaces 16c of the electronic component 16. The top surface conductive portion 41 is in contact with the top surface 16b of the electronic component 16 so as to include the entire area of ​​the orthogonal projection of the IC chip 32 onto the top surface 16b of the electronic component 16. When viewed from the top surface 16b of the electronic component 16, the side surface conductive portion 42 is composed of a first side surface conductive portion 42a formed to protrude in a substantially semi-elliptical shape from the center of each of the two side surfaces 16c of the electronic component 16 on the side where the high-speed signal line 12 does not extend, and a second side surface conductive portion 42b formed to protrude in a substantially semi-elliptical shape from the center of each of the two side surfaces 16c of the electronic component 16 on the side where the high-speed signal line 12 extends. The second side surface conductive portion 42b is arranged so as to contact the center of the side surface 16c, which is located away from the high-speed signal line 12, but not to contact one end of the side surface 16c located on the high-speed signal line 12.

[0025] Next, the function and effect of the heat conduction member in the electronic control device according to the first embodiment will be described using an electronic control device of a comparative example. First, the heat dissipation structure of the electronic control device of the comparative example will be described using Fig. 5. Fig. 5 is a schematic top view showing electronic components on a circuit board and their surrounding structure in an electronic control device of the comparative example compared to the electronic control device according to the first embodiment. In Fig. 5, the same reference numerals as those in Figs. 1 to 4 indicate similar parts, and therefore detailed description thereof will be omitted.

[0026] The electronic control device 100 of the comparative example shown in FIG. 5 has the same configuration and structure of the circuit board 2 and the housing 3 as the electronic control device 1 of the present embodiment, but has a different heat dissipation structure. Specifically, in the electronic control device 100 of the comparative example, the entire outer surface of the electronic component 16 mounted on the first surface 11a of the printed wiring board 11 of the circuit board 2 is thermally connected to the case body 21 (not shown in FIG. 5) of the housing 3 via a heat conduction member 140. That is, the heat conduction member 140 contacts the entire top surface 16b and the entire four side surfaces 16c (the entire outer peripheral surface) of the electronic component 16. Specifically, the heat conduction member 140 has an upper surface conduction portion 141 arranged to extend from the upper surface 16b of the electronic component 16 to the opposing surface 21a of the case body 21 (not shown in FIG. 5), and a side surface conduction portion 142 arranged to contact the entire four side surfaces 16c of the electronic component 16 and extend from the first surface 11a of the printed wiring board 11 to the opposing surface 21a of the case body 21. For this reason, in the electronic control device 100 of the comparative example, a portion of the side conduction portion 142 of the heat conduction member 140 is located in the space above the high-speed signal line 12 of the printed wiring board 11. The material of the heat conduction member 140 in the electronic control device 100 of the comparative example is the same as the material of the heat conduction member 40 in the electronic control device 1 according to the present embodiment.

[0027] Next, the function and effect of the heat conduction member in the electronic control device according to the first embodiment will be described with reference to FIGS. 2 to 5, taking into account the influence of the heat conduction member during operation of an electronic control device of a comparative example.

[0028] During operation of the electronic control device 100 of the comparative example shown in FIG. 5, the electronic component 16 communicates at high speed with other electronic components. If the electronic component 16 is a high-performance component, it may communicate at high speed with memory via a high-speed signal line 12 on the printed wiring board 11. Such communication generates heat from the electronic component 16 and various other electronic components 14 (see FIG. 1) mounted on the printed wiring board 11, causing the temperature of the electronic control device 100 of the comparative example to rise. The heat from the electronic component 16 is transferred from the entire top surface 16b of the electronic component 16 to the top surface conduction portion 141 of the heat conduction member 140 and from the entire four side surfaces 16c of the electronic component 16 to the side surface conduction portion 142 of the heat conduction member 140. The heat transferred to the top surface conduction portion 141 of the heat conduction member 140 and the side surface conduction portion 142 of the heat conduction member 140 are dissipated to the outside of the housing 3 via the case body 21 (see FIG. 1) of the housing 3 and are also transferred to the printed wiring board 11. In the electronic control device 100 of the comparative example, the heat conduction member 140 is arranged so as to contact the entire top surface 16b and the entire four side surfaces 16c of the electronic component 16, thereby improving the heat dissipation effect of the heat conduction member 140.

[0029] However, in the electronic control device 100 of the comparative example, a portion of the side conduction portion 142 of the heat conduction member 140 occupies the space above the high-speed signal line 12 of the printed wiring board 11. This arrangement of the heat conduction member 140 increases the capacitance between the high-speed signal line 12 and the case body 21. The capacitance C is expressed by the following equation (1):

[0030] C=ε·S / L … Equation (1) In formula (1), ε represents the relative dielectric constant, S represents the area of ​​the high-speed signal line 12 in the arrangement region of the heat conduction member 140, and L represents the distance from the high-speed signal line 12 to the case body 21. The relative dielectric constant of air is 1, and the relative dielectric constant of the heat conduction member 140 is, for example, about 8. That is, the relative dielectric constant of the heat conduction member 140 is about 8 times that of air.

[0031] As described above, in the electronic control device 100 of the comparative example, the capacitance between the high-speed signal line 12 of the printed wiring board 11 and the case body 21 increases due to the placement of the heat conduction member 140. This may result in a decrease in the quality of the high-frequency signal transmitted to the high-speed signal line 12 and an increase in radiation noise. If the quality of the high-frequency signal decreases or the radiation noise increases, there is a concern that the high functionality of the electronic control device 100 may decrease.

[0032] In contrast, in the electronic control device 1 according to the present embodiment, the heat conduction member 40 is disposed so as to extend from the first surface 11a of the printed wiring board 11 to the case body 21 of the housing 3 while contacting a portion of the outer peripheral surface 16c of the electronic component 16 at a position that avoids the high-speed signal line 12. As a result, the heat conduction member 40 is not disposed in the region between the high-speed signal line 12 and the case body 21, and air is present, so the capacitance of this region does not increase. Therefore, there is no need to worry about a decrease in the quality of high-frequency signals transmitted through the high-speed signal line 12 or an increase in radiation noise due to the placement of the heat conduction member 40.

[0033] Furthermore, in this embodiment, the heat conduction member 40 is disposed so as to contact not only the top surface 16b of the electronic component 16 but also a portion of each of the four side surfaces 16c. This allows the heat of the electronic component 16 to be transferred to the heat conduction member 40 from the four side surfaces 16c in addition to the top surface 16b, thereby maintaining heat dissipation.

[0034] Furthermore, in this embodiment, the heat conduction member 40 is arranged so as to contact only a portion of each of the four side surfaces 16c of the electronic component 16. The amount of heat conduction member 40 arranged in this manner can be reduced compared to the heat conduction member 140 arranged in the electronic control device 100 of the comparative example so as to contact the entire four side surfaces 16c of the electronic component 16.

[0035] [Modification of the first embodiment] Next, an electronic control device according to a modification of the first embodiment will be described with reference to Figs. 6 to 8. Fig. 6 is a schematic cross-sectional view (cut along the top surface of the electronic component) showing the arrangement of a TIM that contacts the side surface of an electronic component on a circuit board in an electronic control device according to a first modification of the first embodiment. Fig. 7 is a schematic cross-sectional view (cut along the top surface of the electronic component) showing the arrangement of a TIM that contacts the side surface of an electronic component on a circuit board in an electronic control device according to a second modification of the first embodiment. Fig. 8 is a schematic cross-sectional view (cut along the top surface of the electronic component) showing the arrangement of a TIM that contacts the side surface of an electronic component on a circuit board in an electronic control device according to a third modification of the first embodiment.

[0036] The first modified example of the first embodiment shown in FIG. 6 differs from the first embodiment in that the high-speed signal lines 12A connected to the high-speed electronic components 16 on the printed wiring board 11 of the circuit board 2A are arranged differently, and the heat conduction member 40A has a different structure. Specifically, the high-speed signal lines 12A extend from two adjacent side surfaces 16c of the four side surfaces 16c of the electronic component 16. One of the high-speed signal lines 12A extends from the center of one of the adjacent side surfaces 16c of the electronic component 16. Another of the high-speed signal lines 12A extends from the corner of the other of the adjacent side surfaces 16c of the electronic component 16. The heat conduction member 40A is arranged in accordance with the arrangement of the high-speed signal lines 12A on the printed wiring board 11, so as to extend from the first surface 11a of the printed wiring board 11 to the case body 21 of the housing 3 while contacting a portion of the outer peripheral surface 16c of the electronic component 16 at a position that avoids the high-speed signal lines 12A. Specifically, the heat conduction member 40A has a top surface conduction portion 41 (not shown) and side surface conduction portions 42A that are arranged in contact with central portions of side surfaces 16c that are located opposite each other among the four side surfaces 16c of the electronic component 16 and extend from the first surface 11a of the printed wiring board 11 to the case body 21 of the housing 3. The heat conduction member is configured not to be arranged on the side surfaces 16c of the electronic component 16 where the high-speed signal lines 12A are arranged on the central side.

[0037] 7 differs from the first embodiment in that the arrangement of the high-speed signal lines 12B connected to the electronic components 16 on the printed wiring board 11 of the circuit board 2B is different, and that the structure of the heat conduction member 40B is different. Specifically, the high-speed signal lines 12B extend from the center of each of two adjacent side surfaces 16c of the four side surfaces 16c of the electronic component 16. The heat conduction member 40B is arranged in accordance with the arrangement of the high-speed signal lines 12B on the printed wiring board 11, so as to extend from the first surface 11a of the printed wiring board 11 to the case body 21 of the housing 3 while contacting a portion of the outer peripheral surface 16c of the electronic component 16 at a position that avoids the high-speed signal lines 12B. Specifically, the heat conduction member 40B has a top surface conduction portion 41 (not shown) and a side surface conduction portion 42B that is arranged to extend from the first surface 11a of the printed wiring board 11 to the case body 21 of the housing 3 while contacting the entire two adjacent side surfaces 16c, of the four side surfaces 16c of the electronic component 16, on which the high-speed signal line 12B is not arranged. The heat conduction member is configured not to be arranged on the side surfaces 16c of the electronic component 16 on which the high-speed signal line 12A is arranged.

[0038] 8 differs from the first embodiment in that the arrangement of the high-speed signal lines 12C connected to the high-speed electronic components 16 on the printed wiring board 11 of the circuit board 2C is different, and that the structure of the heat conduction member 40C is different. Specifically, the high-speed signal lines 12C extend from the center of two of the four side surfaces 16c of the electronic components 16 that are located opposite each other. The heat conduction member 40C is arranged in accordance with the arrangement of the high-speed signal lines 12C on the printed wiring board 11, so as to extend from the first surface 11a of the printed wiring board 11 to the case body 21 of the housing 3 while contacting a portion of the outer peripheral surface 16c of the electronic components 16 at a position that avoids the high-speed signal lines 12C. Specifically, the heat conduction member 40C has a top surface conduction portion 41 (not shown) and a side surface conduction portion 42C that is arranged to extend from the first surface 11a of the printed wiring board 11 to the case body 21 of the housing 3 while contacting the entire one of the four side surfaces 16c of the electronic component 16 on which the high-speed signal line 12B is not arranged. The heat conduction member is configured not to be arranged on the side surface 16c of the electronic component 16 on which the high-speed signal line 12C is arranged.

[0039] Heat conduction members 40A, 40B, 40C according to the first to third modifications are arranged in accordance with the arrangement of high-speed signal lines 12A, 12B, 12C on printed wiring board 11, so as to extend from first surface 11a of printed wiring board 11 to case body 21 of housing 3 while contacting a portion of outer peripheral surface 16c of electronic component 16 at a position that avoids over high-speed signal lines 12A, 12B, 12C. Therefore, similar to the first embodiment, there is no need to worry about a decrease in the quality of high-frequency signals transmitted through high-speed signal lines 12A, 12B, 12C or an increase in radiation noise due to the arrangement of heat conduction members 40A, 40B, 40C.

[0040] Furthermore, the heat conduction member 40A according to the first modification is arranged so as to contact not only the top surface 16b of the electronic component 16 but also portions of two of the four side surfaces 16c. Therefore, heat from the electronic component 16 is transferred from the two side surfaces 16c in addition to the top surface 16b, thereby maintaining heat dissipation. Furthermore, because the heat conduction member 40A is arranged so as to contact portions of two of the four side surfaces 16c of the electronic component 16, the amount of heat conduction member 40A used can be reduced compared to the heat conduction member 40 according to the first embodiment, which contacts portions of each of the four side surfaces 16c of the electronic component 16.

[0041] Furthermore, the heat conduction member 40B according to the second modification is disposed so as to be in contact with the entire two of the four side surfaces 16c as well as the top surface 16b of the electronic component 16. Therefore, heat from the electronic component 16 is transferred from the entire two side surfaces 16c as well as the top surface 16b, thereby maintaining heat dissipation properties.

[0042] Furthermore, the heat conduction member 40C according to the third modification is disposed so as to be in contact with the entirety of one of the four side surfaces 16c in addition to the upper surface 16b of the electronic component 16. Therefore, heat from the electronic component 16 is transferred from the entirety of the one side surface 16c in addition to the upper surface 16b, thereby maintaining heat dissipation properties.

[0043] As described above, the electronic control device 1 according to the first embodiment and its modifications includes: a printed wiring board 11 (wiring board) on which a wiring pattern including high-speed signal lines 12, 12A, 12B, and 12C is formed; circuit boards 2, 2A, 2B, and 2C having electronic components 16 mounted on a first surface 11a of the printed wiring board 11 (wiring board) and electrically connected to the high-speed signal lines 12, 12A, 12B, and 12C; a housing 3 that houses the circuit boards 2, 2A, 2B, and 2C; and heat conduction members 40, 40A, 40B, and 40C (first heat conduction members) that are in direct contact with the electronic components 16 and the housing 3. The electronic components 16 have a bottom surface 16a facing the first surface 11a of the printed wiring board 11 (wiring board), a top surface 16b located opposite the bottom surface 16a, and an outer circumferential surface 16c that is connected to the outer edges of the bottom surface 16a and the top surface 16b. The heat conduction members 40, 40A, 40B, 40C (first heat conduction members) are arranged to extend from the upper surface 16b of the electronic component 16 to the housing 3, and are also arranged to extend from the first surface 11a of the printed wiring board 11 (wiring board) to the housing 3 while contacting a portion of the outer peripheral surface 16c of the electronic component 16 at a position that avoids the high-speed signal lines 12, 12A, 12B, 12C.

[0044] According to this configuration, the heat conduction members 40, 40A, 40B, 40C (first heat conduction members) are arranged so as to contact a portion of the upper surface 16b and the outer peripheral surface 16c of the electronic component 16, thereby maintaining heat dissipation, and the heat conduction members 40, 40A, 40B, 40C (first heat conduction members) are arranged at positions that avoid over the high-speed signal lines 12, 12A, 12B, 12C, thereby preventing an increase in capacitance between the high-speed signal lines 12, 12A, 12B, 12C and the housing 3 due to the arrangement of the heat conduction members 40, 40A, 40B, 40C (first heat conduction members). This makes it possible to ensure the quality of high-frequency signals and suppress radiation noise while maintaining heat dissipation.

[0045] Furthermore, electronic component 16 in electronic control device 1 according to the first embodiment is configured in a rectangular shape when viewed from top surface 16b, and has four side surfaces as outer peripheral surface 16c. Heat conduction member 40 (first heat conduction member) is disposed so as to extend from first surface 11a of printed wiring board 11 (wiring board) to housing 3 while contacting a portion of each of four side surfaces 16c of electronic component 16 at a position avoiding high-speed signal line 12.

[0046] According to this configuration, heat from the electronic component 16 is transferred to the heat conduction member 40 (first heat conduction member) from each of the four side surfaces 16c in addition to the top surface 16b, thereby improving heat dissipation compared to a case in which the heat conduction member 40 (first heat conduction member) does not come into contact with any of the four side surfaces 16c of the electronic component 16.

[0047] Furthermore, the electronic control device 1 according to the first embodiment has an IC chip 32 (chip) as a heat source with a built-in electronic component. The heat conduction member 40 (first heat conduction member) is in contact with the upper surface 16b of the electronic component 16 so as to include the entire area of ​​the orthogonal projection of the IC chip 32 (chip) onto the upper surface 16b of the electronic component 16.

[0048] According to this configuration, the heat conduction member 40 (first heat conduction member) is in contact with an area of ​​the upper surface 16b of the electronic component 16 that becomes relatively hot due to the heat from the heat source, the IC chip 32 (chip), thereby improving the heat dissipation properties of the heat conduction member 40 (first heat conduction member).

[0049] [Second embodiment] Next, an electronic control device according to a second embodiment of the present invention will be described with reference to Figures 9 and 10. Figure 9 is a perspective view showing electronic components on a circuit board and their peripheral structure in an electronic control device according to the second embodiment of the present invention. Figure 10 is a schematic bottom view showing electronic components on a circuit board and their peripheral structure in an electronic control device according to the second embodiment.

[0050] 9 and 10 differs from the first embodiment mainly in that a heat conduction member 50 is disposed on the opposite side of the heat conduction member 40 across the printed wiring board 11 of the circuit board 2D, and that a heat conduction path 13 is provided on the printed wiring board 11 of the circuit board 2D to thermally connect the heat conduction member 50 to the heat conduction member 40. The rest of the structure of the electronic control device 1D according to the second embodiment is similar to the structure of the electronic control device 1 according to the first embodiment, and therefore a description thereof will be omitted.

[0051] Specifically, the heat conduction paths 13 of the circuit board 2D are through-holes that penetrate from the first surface 11a to the second surface 11b of the printed wiring board 11, and have conductive plating applied to their inner surfaces. The heat conduction paths 13 are arranged in positions that allow thermal connection to the heat conduction member 40 on the case body 21 side, i.e., in areas where the side conduction portions 42 of the heat conduction member 40 are in contact with the first surface 11a of the printed wiring board 11. For example, four heat conduction paths 13 are arranged so that they are thermally connected to the side conduction portions 42 that contact each side surface 16c of the electronic component 16, respectively.

[0052] The heat conduction member 50 is disposed so as to extend from the second surface 11b of the printed wiring board 11 of the circuit board 2D to the protrusion 22a of the cover 22 of the housing 3. Like the heat conduction member 40 of the case body 21, the heat conduction member 50 on the cover 22 side is made of resin to which a thermally conductive filler has been added. For example, a thermal interface material (TIM) such as thermal grease or a thermally conductive sheet is used as the heat conduction member 50. The heat conduction member 50 on the cover 22 side is disposed so as to be in direct contact with the heat conduction path 13 of the circuit board 2D and is configured to be thermally connected to the heat conduction member 40 on the case body 21 side via the heat conduction path 13. The heat conduction member 50 is formed, for example, so that the shape of its orthogonal projection onto the printed wiring board 11 is substantially the same as the shape of the heat conduction member 40 on the case body 21 side when orthogonally projected onto the printed wiring board 11. The shape of the heat conduction member 50 may be any shape as long as it can be in direct contact with the heat conduction path 13.

[0053] In this embodiment, the heat conduction member 40, which is in direct contact with the electronic component 16 and the case body 21 of the housing 3, is thermally connected to the heat conduction member 50, which is in direct contact with the cover 22 of the housing 3, via the heat conduction path 13 of the circuit board 2D. As a result, heat from the electronic component 16 is not only transferred to the case body 21 via the heat conduction member 40 and released to the outside of the housing 3, but also transferred from the heat conduction member 40 to the heat conduction member 50 via the heat conduction path 13 and finally to the cover 22 and released to the outside of the housing 3. In other words, a heat dissipation path from the electronic component 16 to the outside of the housing 3 is secured on the cover 22 side in addition to the case body 21 side, so that heat can be dissipated from both the case body 21 and the cover 22 of the housing 3.

[0054] [First Modification of the Second Embodiment] Next, an electronic control device according to a first modified example of the second embodiment will be described with reference to Figures 11 and 12. Figure 11 is a perspective view showing electronic components on a circuit board and their peripheral structure in an electronic control device according to a first example of the first modified example of the second embodiment. Figure 12 is a perspective view showing electronic components on a circuit board and their peripheral structure in an electronic control device according to a second example of the first modified example of the second embodiment.

[0055] The main differences between the electronic control device 1E according to the first example of the first modified example of the second embodiment shown in FIG. 11 and the second embodiment are as follows. First, the structure of the heat conduction member 40E on the case body 21 side is different. Second, the structure of the heat conduction member 50E on the cover 22 side is different depending on the structure of the heat conduction member 40E on the case body 21 side. Third, the arrangement of the heat conduction path 13E of the circuit board 2E is different depending on the structures of the heat conduction member 40E on the case body 21 side and the heat conduction member 50E on the cover 22 side.

[0056] Specifically, the heat conduction member 40E on the case body 21 side is disposed so as to contact the top surface 16b of the electronic component 16 as well as the entirety of three of the four side surfaces 16c. That is, the heat conduction member 40E has a top surface conduction portion 41 that contacts the top surface 16b of the electronic component 16 and three side surface conduction portions 42E that contact the entirety of the three side surfaces 16c of the electronic component 16. For example, three heat conduction paths 13E (only two are shown in FIG. 11 ) are disposed so as to contact the three side surface conduction portions 42E of the heat conduction member 40E, respectively. The heat conduction member 50E on the cover 22 side is disposed at a position that avoids the area directly below the electronic component 16 on the second surface 11b of the printed wiring board 11 and includes the position of the heat conduction path 13E. The heat conduction member 50E is configured, for example, so that the shape of its orthogonal projection onto the printed wiring board 11 is similar to the shape of the orthogonal projection onto the printed wiring board 11 of the three side conduction portions 42E of the heat conduction member 40E on the case body 21 side.

[0057] The main differences between the electronic control device 1F according to the second example of the first modified example of the second embodiment shown in FIG. 12 and the second embodiment are as follows: First, the structure of the heat conduction member 40F on the case body 21 side is different. Second, the structure of the heat conduction member 50F on the cover 22 side is different depending on the structure of the heat conduction member 40F on the case body 21 side. Third, the arrangement of the heat conduction path 13F of the circuit board 2F is different depending on the structures of the heat conduction member 40F on the case body 21 side and the heat conduction member 50F on the cover 22 side.

[0058] Specifically, the heat conduction member 40F on the case body 21 side is disposed so as to contact not only the top surface 16b of the electronic component 16 but also the entire two adjacent side surfaces 16c of the electronic component 16. That is, the heat conduction member 40F has a top surface conduction portion 41 that contacts the top surface 16b of the electronic component 16 and two side surface conduction portions 42F that contact the entire two adjacent side surfaces 16c of the electronic component 16. For example, two heat conduction paths 13F (only one is shown in FIG. 12 ) are disposed so as to contact the two side surface conduction portions 42F of the heat conduction member 40F, respectively. The heat conduction member 50F on the cover 22 side is disposed at a position that avoids the area directly below the electronic component 16 on the second surface 11b of the printed wiring board 11 and includes the position of the heat conduction path 13F. The heat conduction member 50F is configured, for example, so that the shape of its orthogonal projection onto the printed wiring board 11 is similar to the shape (L-shape) of the two side conduction portions 42F of the heat conduction member 40F on the case body 21 side when orthogonally projected onto the printed wiring board 11.

[0059] In the circuit boards 2E and 2F of the first and second examples of the first modified example of the second embodiment, wiring and chip components may be densely mounted in the area behind the mounting portion of the high-performance electronic component 16 on the second surface 11b of the printed wiring board 11. In this case, limitations are imposed on the placement of the heat conduction members 50E and 50F on the cover 22. The heat conduction members 50E and 50F on the cover 22 have a structure that takes such a case into account. The heat conduction members 50E and 50F are thermally connected to the heat conduction members 40E and 40F via the heat conduction paths 13E and 13F of the circuit boards 2E and 2F to transfer heat from the electronic component 16 to the cover 22. Therefore, there is no need to place the heat conduction members 50E and 50F over the entire area behind the mounting portion of the electronic component 16 on the second surface 11b of the printed wiring board 11.

[0060] Furthermore, in the first and second examples of the first modified example, similarly to the second embodiment, the heat conduction members 40E, 40F in direct contact with the electronic component 16 are thermally connected to the heat conduction members 50E, 50F via the heat conduction paths 13E, 13F of the circuit boards 2E, 2F. As a result, the heat of the electronic component 16 is not only transferred to the case body 21 via the heat conduction members 40E, 40F and released to the outside of the housing 3, but also transferred from the heat conduction members 40E, 40F to the heat conduction members 50E, 50F via the heat conduction paths 13E, 13F and finally to the cover 22 and released to the outside of the housing 3. In other words, since a heat dissipation path from the electronic component 16 to the outside of the housing 3 is secured on both the case body 21 side and the cover 22 side, heat dissipation from both the case body 21 and the cover 22 of the housing 3 is possible.

[0061] [Second Modification of the Second Embodiment] Next, an electronic control device according to a second modified example of the second embodiment will be described with reference to Figures 13 and 14. Figure 13 is a cross-sectional view showing electronic components on a circuit board and their peripheral structure in an electronic control device according to a first example of the second modified example of the second embodiment. Figure 14 is a cross-sectional view showing electronic components on a circuit board and their peripheral structure in an electronic control device according to a second example of the second modified example of the second embodiment.

[0062] 13 is different from the first example of the first modified example of the second embodiment in the arrangement and number of heat conduction paths 13G of the circuit board 2G. Specifically, the heat conduction paths 13G are arranged in two rows spaced apart from each other along the circumferential direction of the side surface 16c of the electronic component 16, rather than being arranged one for each of the three side surface conduction portions 42E of the heat conduction member 40E on the case body 21 side.

[0063] 14 according to a second example of the second modified example of the second embodiment differs from the first example of the second modified example of the second embodiment in the arrangement and number of heat conduction paths 13H of the circuit board 2G. Specifically, the heat conduction paths 13H are arranged in four rows at intervals along the circumferential direction of the side surface 16c of the electronic component 16 for each of the three side surface conduction portions 42E of the heat conduction member 40E on the case body 21 side.

[0064] In the first and second examples of the second modified example of the second embodiment, similarly to the first example of the first modified example of the second embodiment, the heat conduction member 40E in direct contact with the electronic component 16 is thermally connected to the heat conduction member 50E via the heat conduction paths 13G and 13H of the circuit boards 2G and 2H. As a result, the heat of the electronic component 16 is not only transferred to the case body 21 via the heat conduction member 40E and released to the outside of the housing 3, but also transferred from the heat conduction member 40E to the heat conduction member 50E via the heat conduction paths 13G and 13H and finally to the cover 22 and released to the outside of the housing 3. In other words, since a heat dissipation path from the electronic component 16 to the outside of the housing 3 is secured on both the case body 21 side and the cover 22 side, heat dissipation from both the case body 21 and the cover 22 of the housing 3 is possible.

[0065] Furthermore, in the first and second examples of the second modified example, the heat conduction paths 13G, 13H of the circuit boards 2G, 2H are arranged in two or four rows (multiple rows) along the side surface 16c of the electronic component 16 and are configured to contact the heat conduction member 40 on the case body 21 side and the heat conduction member 50E on the cover 22 side. This configuration allows efficient heat transfer from the heat conduction member 40E on the case body 21 side to the heat conduction member 50E on the cover 22 side via the heat conduction paths 13G, 13H. Therefore, the amount of heat transferred from the electronic component 16 to the heat conduction member 50E on the cover 22 side via the heat conduction paths 13G, 13H is greater than in the first and second examples of the first modified example of the second embodiment, thereby improving heat dissipation.

[0066] [Third Modification of the Second Embodiment] Next, an electronic control device according to a third modified example of the second embodiment will be described with reference to Figures 15 to 17. Figure 15 is a schematic diagram showing the layout relationship between electronic components and heat conduction paths (through holes) on a circuit board in an electronic control device according to a first example of the third modified example of the second embodiment. Figure 16 is a schematic diagram showing the layout relationship between electronic components and heat conduction paths (through holes) on a circuit board in an electronic control device according to a second example of the third modified example of the second embodiment. Figure 17 is a contour diagram showing the heat flow rate on the circuit board in an electronic control device according to the first example of the third modified example of the second embodiment.

[0067] 15 differs from the second embodiment in the arrangement of the heat conduction paths 13J of the circuit board 2J. Specifically, like the heat conduction paths 13 of the circuit board 2D according to the second embodiment, the heat conduction paths 13J of the circuit board 2J according to the first example of the third modified example of the second embodiment are arranged so as to correspond to the centers of the four side surfaces 16c of the electronic component 16, one for each side surface, but are arranged closer to the centers of the side surfaces 16c of the electronic component 16 than the heat conduction paths 13 according to the second embodiment.

[0068] 16 differs from the first example of the third modified example of the second embodiment in the arrangement of the heat conduction paths 13K of the circuit board 2K. Specifically, unlike the heat conduction paths 13J of the first example of the third modified example of the second embodiment, the heat conduction paths 13K of the circuit board 2K of the second example of the third modified example of the second embodiment are arranged so that one of the heat conduction paths 13K corresponds to each of two adjacent side surfaces 16c of the electronic component 16, and like the heat conduction paths 13J of the second example of the third modified example, the heat conduction paths 13K are arranged in close proximity to the center of the side surfaces 16c of the electronic component 16.

[0069] In the electronic control devices according to the first and second examples of the third modified example of the second embodiment, the heat conduction paths 13J, 13K of the circuit boards 2J, 2K are arranged at a position corresponding to the center of at least one of the four side surfaces 16c of the electronic component 16. As can be seen from the results of the thermal fluid analysis shown in FIG. 17, heat from the IC chip 32 located at the center of the electronic component 16 is conducted radially, so that the heat from the IC chip 32 is conducted most to the center of each side surface 16c of the electronic component 16. Therefore, heat can be efficiently conducted from the heat conduction member (not shown) on the case body 21 side to the heat conduction member (not shown) on the cover 22 side via the heat conduction paths 13J, 13K of the circuit boards 2J, 2K.

[0070] In the first and second examples of the third variant of the second embodiment, the electronic component 16 has an IC chip 32 as a heat source at its center, and multiple heat conduction paths 13J, 13K of the circuit boards 2J, 2K are arranged at equal distances from the IC chip 32 as the heat source of the electronic component 16.

[0071] According to this configuration, heat from the heat source IC chip 32 is transmitted radially, so that the amount of heat transmitted to the multiple heat conduction paths 13J, 13K located at equal distances from the IC chip 32 is approximately the same, thereby enabling even heat dissipation.

[0072] In the first and second examples of the third modified example of the second embodiment, it is preferable that the heat conduction paths 13J and 13K of the circuit boards 2J and 2K are disposed at positions closest to the outer peripheral surface 16c of the electronic component 16. With this configuration, the heat radially transferred from the electronic component 16 can be efficiently guided to the heat conduction paths 13J and 13K.

[0073] As described above, according to the second embodiment and its modified example, similarly to the first embodiment, the heat conduction members 40, 40E, 40F (first heat conduction members) are arranged so as to contact a portion of the upper surface 16b and the outer peripheral surface 16c of the electronic component 16, thereby maintaining heat dissipation, and the heat conduction members 40, 40E, 40F (first heat conduction members) are arranged at positions that avoid the high-speed signal line 12, thereby preventing an increase in the capacitance between the high-speed signal line 12 and the housing 3 due to the arrangement of the heat conduction members 40, 40E, 40F (first heat conduction members). This makes it possible to ensure the quality of high-frequency signals and suppress radiation noise while maintaining heat dissipation.

[0074] Furthermore, in this embodiment and its variant, circuit boards 2D, 2E, 2F, 2G, 2H, 2J, and 2K have heat conduction paths 13, 13E, 13F, 13G, 13H, 13J, and 13K provided on printed wiring board 11 (wiring board), and heat conduction paths 13, 13E, 13F, 13G, 13H, 13J, and 13K of circuit boards 2D, 2E, 2F, 2G, 2H, 2J, and 2K are arranged in positions where they can be thermally connected to heat conduction members 40, 40E, and 40F (first heat conduction members).

[0075] According to this configuration, in addition to the heat being transferred from the heat conductive members 40, 40E, 40F (first heat conductive members) to the housing 3, the heat is also transferred from the heat conductive members 40, 40E, 40F (first heat conductive members) to the printed wiring board 11 (wiring board) side of the circuit boards 2D, 2E, 2F, 2G, 2H, 2J, 2K via the heat conduction paths 13, 13E, 13F, 13G, 13H, 13J, 13K of the circuit boards 2D, 2E, 2F, 2G, 2H, 2J, 2K, thereby improving the heat dissipation performance compared to the first embodiment and its modified examples.

[0076] Moreover, the electronic control devices according to the present embodiment and its modifications further include heat conduction members 50, 50E, 50F (second heat conduction members) that are in direct contact with housing 3 and second surface 11b, which is located behind first surface 11a of printed wiring board 11 (wiring board). Heat conduction members 50, 50E, 50F (second heat conduction members) are thermally connected to heat conduction members 40, 40E, 40F (first heat conduction members) via heat conduction paths 13, 13E, 13F, 13G, 13H, 13J, 13K of circuit boards 2D, 2E, 2F, 2G, 2H, 2J, 2K.

[0077] According to this configuration, the heat of the electronic component 16 is not only transferred to one side of the housing 3 (case body 21) via the heat conduction members 40, 40E, and 40F (first heat conduction members) and released to the outside, but also transferred to the heat conduction members 50, 50E, and 50F (second heat conduction members) via the heat conduction paths 13, 13E, 13F, 13G, 13H, 13J, and 13K, and finally transferred to the other side of the housing 3 (cover 22) and released to the outside. In other words, two heat dissipation paths from the electronic component 16 to the outside of the housing 3 are secured, one on one side and the other on the other side of the housing 3. This improves heat dissipation.

[0078] In addition, in the second embodiment, the heat conduction member 40 (first heat conduction member) is positioned so as to contact a portion of each of the four side surfaces 16c of the electronic component 16 at a position that avoids the high-speed signal line 12, and the heat conduction path 13 of the circuit board 2D is positioned corresponding to each of the four side surfaces 16c of the electronic component 16.

[0079] According to this configuration, heat from the electronic component 16 is transferred to the heat conduction path 13 arranged corresponding to the four side surfaces 16c of the electronic component 16 via the heat conduction member 40 (first heat conduction member) in contact with the four side surfaces 16c of the electronic component 16, thereby enabling efficient heat transfer from the electronic component 16 to the heat conduction path 13 and improving heat dissipation.

[0080] [Third embodiment] Next, an electronic control device according to a third embodiment of the present invention will be described with reference to Fig. 18. Fig. 18 is a schematic cross-sectional view showing electronic components on a circuit board and the surrounding structure in an electronic control device according to the third embodiment of the present invention.

[0081] An electronic control device 1L according to a third embodiment shown in FIG. 18 differs from the second embodiment in that it further includes a heat-conducting member 60 interposed between the first surface 11a of the printed wiring board 11 and the bottom surface 16a of the electronic component 16. Specifically, the heat-conducting member 60 is an underfill that reinforces the solder joint between the solder balls 33 on the bottom surface 16a of the electronic component 16 and the wiring pattern on the first surface 11a of the printed wiring board 11. The underfill 60 improves the solder connection life and is made of, for example, epoxy resin, and also functions as a heat-conducting member. The rest of the structure of the electronic control device 1L according to the third embodiment is similar to the structure of the electronic control device 1D according to the second embodiment, and therefore a description thereof will be omitted.

[0082] In this embodiment, in addition to the thermally conductive member 40 on the case body 21 side and the thermally conductive member 50 on the cover 22 side, the underfill 60 interposed between the printed wiring board 11 and the electronic component 16 on the circuit board 2L functions as a thermally conductive member for transferring heat from the electronic component 16. This makes it possible to increase the amount of heat transferred from the electronic component 16 to the printed wiring board 11 while improving the reliability of the solder connection between the electronic component 16 and the printed wiring board 11. Therefore, it is possible to achieve both an improvement in the solder life and an improvement in heat dissipation.

[0083] According to the third embodiment, similarly to the first embodiment, the heat conduction member 40 (first heat conduction member) is arranged so as to contact a portion of the upper surface 16b and the outer peripheral surface 16c of the electronic component 16, thereby maintaining heat dissipation, and the heat conduction member 40 (first heat conduction member) is arranged at a position that avoids being located on a high-speed signal line (not shown), thereby preventing an increase in capacitance between the high-speed signal line and the housing 3 due to the arrangement of the heat conduction member 40 (first heat conduction member). This makes it possible to ensure the quality of high-frequency signals and suppress radiation noise while maintaining heat dissipation.

[0084] Moreover, the electronic control device 1L according to the third embodiment further includes a heat conduction member 60 interposed between the first surface 11a of the printed wiring board 11 (wiring board) and the bottom surface 16a of the electronic component 16.

[0085] According to this configuration, the heat of the electronic component 16 can be transferred to the housing 3 via the heat conductive member 40, and also to the printed wiring board 11 (wiring board) via the heat conductive member 60. This improves heat dissipation.

[0086] In this embodiment, the heat conducting member 60 (third heat conducting member) is an underfill that reinforces the solder joints on the bottom surface 16a side of the electronic component 16.

[0087] According to this configuration, the heat conducting member 60 can improve the solder life and heat dissipation.

[0088] [Fourth embodiment] Next, an electronic control device according to a fourth embodiment of the present invention will be described with reference to Fig. 19. Fig. 19 is a schematic perspective view showing the appearance of an electronic control device according to the fourth embodiment of the present invention. In Fig. 19, the same reference numerals as those shown in Figs. 1 to 18 denote similar parts, and detailed description thereof will be omitted.

[0089] 19 is different from the first embodiment in that a cooling fan 70 is attached to the case body 21 of the housing 3. The electronic control device 1M is of a forced air-cooling type in which cooling air generated by the cooling fan 70 is supplied to the heat dissipation fins 25 of the case body 21.

[0090] In this embodiment, heat transferred from electronic component 16 shown in Fig. 2 to case body 21 of housing 3 via heat conduction member 40 is released by cooling air generated by cooling fan 70 shown in Fig. 19. This reduces the temperature of housing 3 and increases the temperature difference with electronic component 16, thereby accelerating heat transfer from electronic component 16 to housing 3. This further improves the heat dissipation performance of electronic control device 1M.

[0091] As described above, the electronic control device 1M according to this embodiment further includes a cooling fan 70 that supplies cooling air to the outer surface of the housing 3. This configuration promotes heat transfer from the electronic components 16 to the housing 3, further improving the heat dissipation performance of the electronic control device 1M.

[0092] [Fifth embodiment] Next, an electronic control device according to a fifth embodiment of the present invention will be described with reference to Fig. 20. Fig. 20 is a schematic perspective view showing the appearance of the electronic control device according to the fifth embodiment. In Fig. 20, the same reference numerals as those shown in Figs. 1 to 19 denote similar parts, and detailed description thereof will be omitted.

[0093] An electronic control device 1N according to a fifth embodiment shown in Fig. 20 differs from the first embodiment in that it includes a water-cooling system 80 that supplies cooling water to the housing 3 for cooling. Specifically, the water-cooling system 80 includes a supply line 81 that supplies cooling water to the housing 3, and a discharge line 82 through which the cooling water discharged from the housing 3 flows. The electronic control device 1 is of a forced water-cooling type in which the housing 3 is cooled by the cooling water supplied from the supply line 81 and then discharged to the discharge line 82.

[0094] In this embodiment, heat transferred from electronic component 16 shown in Fig. 2 to case body 21 of housing 3 via heat conduction member 40 is released by cooling water in water-cooling system 80 shown in Fig. 20. This reduces the temperature of housing 3, increasing the temperature difference with electronic component 16, thereby accelerating heat transfer from electronic component 16 to housing 3. This further improves the heat dissipation performance of electronic control device 1M from electronic component 16.

[0095] As described above, the electronic control device 1N according to this embodiment further includes the water-cooling system 80 that supplies cooling water to the housing 3 for cooling. This configuration promotes heat transfer from the electronic components 16 to the housing 3, further improving the heat dissipation performance of the electronic control device 1M.

[0096] [Other embodiments] It should be noted that the present invention is not limited to the above-described embodiments and includes various modifications. The above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0097] For example, in the above-described embodiment, an example has been shown in which the electronic control device 1 is configured as an electronic control device mounted on a vehicle to control or assist vehicle driving. However, the electronic control device may also be configured to be mounted on a device other than a vehicle as long as it is an electronic control device that performs high-speed communication. For example, the electronic control device may also be applied to an electronic control device of an unmanned aerial vehicle (drone) or the like.

[0098] In the above-described embodiment, the electronic component 16 capable of high-speed operation has been shown to have a semiconductor package with a BGA structure. However, the high-speed processing electronic component can also have a surface-mount semiconductor package with a QFP (Quad Flat Package) structure, a QFN (Quad Flat Non-leaded package), or an SOP (Small Outline Package) structure. The high-speed electronic component can also have an insertion-mount semiconductor package with a PGA (Pin Grid Array) structure. [Explanation of symbols]

[0099] 1, 1D, 1E, 1F, 1G, 1H, 1L, 1M, 1N...Electronic control device, 2, 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2J, 2K, 2L...Circuit board, 3...Housing, 11...Printed wiring board (wiring board), 11a...First surface, 11b...Second surface, 12, 12A, 12B, 12C...High-speed signal line, 13, 13E, 13F, 13G, 13H, 13J, 13K...Heat conduction path, 16...Electronic component, 16a...Bottom surface, 16b...Top surface, 16c...Outer peripheral surface (side surface), 32...IC chip (chip), 40, 40A, 40B, 40C, 40E, 40F...Heat conduction member (first heat conduction member), 50, 50E, 50F...Heat conductive member (second heat conductive member), 60...Underfill (third heat conductive member), 70...Cooling fan, 80...Water cooling system

Claims

1. a circuit board having a wiring board on which a wiring pattern including high-speed signal lines is formed and an electronic component mounted on a first surface of the wiring board and electrically connected to the high-speed signal lines; a housing that houses the circuit board; a first heat conducting member in direct contact with the electronic component and the housing; the electronic component has a bottom surface facing the first surface of the wiring board, a top surface located on the opposite side of the bottom surface, and an outer circumferential surface connected to an outer edge of the bottom surface and an outer edge of the top surface, The first heat conduction member is arranged to extend from the top surface of the electronic component to the housing, and is arranged to extend from the first surface of the wiring board to the housing while contacting a portion of the outer circumferential surface of the electronic component at a position that avoids the high-speed signal line. An electronic control device characterized by:

2. 2. The electronic control device according to claim 1, The electronic component is configured to have a rectangular shape when viewed from the top surface side, and has four side surfaces as the outer circumferential surface, The first heat conducting member is disposed so as to extend from the first surface of the wiring board to the housing while contacting a portion of each of the four side surfaces of the electronic component at a position that avoids the high-speed signal line. An electronic control device characterized by:

3. 2. The electronic control device according to claim 1, the electronic component has a chip as a built-in heat source, The first thermal conductive member is in contact with the top surface of the electronic component so as to cover the entire area of ​​an orthogonal projection of the chip onto the top surface of the electronic component. An electronic control device characterized by:

4. 2. The electronic control device according to claim 1, the circuit board has a heat conduction path provided in the wiring board, The heat conduction path of the circuit board is disposed at a position where it can be thermally connected to the first heat conduction member. An electronic control device characterized by:

5. 5. The electronic control device according to claim 4, a second heat conduction member that is in direct contact with the housing and a second surface of the wiring board that is located on the back side of the first surface, The second heat conducting member is thermally connected to the first heat conducting member via the heat conducting path of the circuit board. An electronic control device characterized by:

6. 5. The electronic control device according to claim 4, The electronic component is configured to have a rectangular shape when viewed from the top surface side, and has four side surfaces as the outer circumferential surface, The heat conduction path of the circuit board is disposed at a position corresponding to a center portion of at least one of the four side surfaces of the electronic component. An electronic control device characterized by:

7. 5. The electronic control device according to claim 4, The electronic component is configured to have a rectangular shape when viewed from the top surface side, and has four side surfaces as the outer circumferential surface, the first heat conducting member is disposed so as to contact a portion of each of the four side surfaces of the electronic component at a position that avoids the high-speed signal line; The heat conduction paths of the circuit board are arranged corresponding to each of the four side surfaces of the electronic component. An electronic control device characterized by:

8. 5. The electronic control device according to claim 4, The heat conduction path of the circuit board is disposed at a position closest to the outer peripheral surface of the electronic component. An electronic control device characterized by:

9. 5. The electronic control device according to claim 4, the electronic component has a heat source at its center, The heat conduction paths of the circuit board are arranged at equal distances from the heat source of the electronic component. An electronic control device characterized by:

10. 5. The electronic control device according to claim 4, The heat conduction paths of the circuit board are arranged in a plurality of rows in a direction along the outer circumferential surface of the electronic component. An electronic control device characterized by:

11. 2. The electronic control device according to claim 1, a third heat conducting member interposed between the first surface of the wiring board and the bottom surface of the electronic component. An electronic control device characterized by:

12. 12. The electronic control device according to claim 11, The third thermal conductive member is an underfill that reinforces the solder joints on the bottom side of the electronic component. An electronic control device characterized by:

13. 2. The electronic control device according to claim 1, Further provided is a cooling fan for supplying cooling air to the outer surface of the housing. An electronic control device characterized by:

14. 2. The electronic control device according to claim 1, The housing further includes a water cooling system that supplies cooling water to the housing. An electronic control device characterized by:

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