Electronic control unit

Abstract

To provide an electronic control device which can improve electromagnetic compatibility while preventing unnecessary expansion of a conductive connection part on the surface of a circuit board.SOLUTION: An electronic control device has a circuit board 110, a resin base part 120, a metallic cover, a conductive connection part 140, and a fluidization prevention part 150. The circuit board 110 has an object wiring 111 as an object of noise reduction, an electronic component 112 mounted on the vicinity of the object wiring 111, a signal ground 114 connected to the electronic component 112, and a housing ground 113 which is connected to the signal ground 114 through the electronic component 112 and is connected to the cover through the conductive connection part 140. The fluidization prevention part 150 has a communication passage 151 between the conductive connection part 140 and the electronic component 112. The housing ground 113 has a first connection part 113a connected to the conductive connection part 140, a second connection part 113b connected to the electronic component 112, and a communication part 113c which passes through the communication passage 151 and connects the first connection part 113a and the second connection part 113b.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to an electronic control device.

Background Art

[0002] Conventionally, electronic control devices have been known. For example, the electronic control device described in Patent Document 1 below includes a resin base, a circuit board on which electronic components are mounted, a metal cover that covers the circuit board, and a conductive connection portion that conductively connects the metal cover and the ground circuit of the circuit board. In this electronic control device, the circuit board is sandwiched between the base and the metal cover, a convex member is disposed between the conductive connection portion and the electronic component, and the conductive connection portion and the convex member are in contact with each other (Patent Document 1, Paragraph 0011, Claim 1).

[0003] According to this conventional electronic control device, when installing a conductive material at a predetermined position on the circuit board, unnecessary spread on the circuit board surface can be prevented. Therefore, even when the component prohibition zone on the circuit board is set small, contact between the conductive material and the electronic components and wiring patterns on the circuit board can be prevented, and damage to the circuit can be prevented (Patent Document 1, Paragraph 0012).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the electronic control devices described above, there is a need to suppress emissions (EMI) and improve immunity (EMS), that is, to further improve electromagnetic compatibility (EMC). However, as mentioned above, in the conventional electronic control devices described above, while the placement of a convex member between the conductive connection part and the electronic component can prevent the unnecessary spreading of conductive material on the circuit board surface, the convex member may hinder the improvement of EMC.

[0006] This disclosure provides an electronic control device that can improve EMC while preventing conductive connection parts from unnecessarily spreading on the surface of a circuit board. [Means for solving the problem]

[0007] One aspect of the present disclosure is an electronic control device comprising a circuit board, a resin base supporting the circuit board, a metal cover covering the circuit board supported by the base, a conductive connection portion connecting the cover to the circuit board, and a flow prevention portion preventing the spreading of the conductive connection portion, wherein the circuit board comprises a target wiring to be noise reduced, an electronic component mounted near the target wiring, a signal ground connected to the electronic component, and a housing ground connected to the signal ground via the electronic component and to the cover via the conductive connection portion, the flow prevention portion having a communication passage between the conductive connection portion and the electronic component, and the housing ground comprising a first connection portion connected to the conductive connection portion, a second connection portion connected to the electronic component, and a communication portion connecting the first connection portion and the second connection portion through the communication passage of the flow prevention portion. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, it is possible to provide an electronic control device that can improve EMC while preventing conductive connection portions from unnecessarily spreading on the surface of the circuit board. [Brief explanation of the drawing]

[0009] [Figure 1] An exploded perspective view showing one embodiment of the electronic control device relating to this disclosure. [Figure 2] A schematic enlarged plan view of the base and peripheral edge of the circuit board of the electronic control unit shown in Figure 1. [Figure 3] A schematic enlarged cross-sectional view of the electronic control unit along line III-III in Figure 2. [Figure 4] A schematic enlarged cross-sectional view of the electronic control unit along line IV-IV in Figure 2. [Figure 5] A schematic enlarged plan view showing a modified example of the electronic control device in Figure 2. [Figure 6] A schematic enlarged plan view showing a modified example of the electronic control device in Figure 2. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the electronic control device according to this disclosure will be described with reference to the drawings.

[0011] Figure 1 is an exploded perspective view showing one embodiment of the electronic control device according to the present disclosure. Figure 2 is a schematic enlarged plan view of the base portion 120 and the peripheral portion of the circuit board 110 of the electronic control device 100 of Figure 1. Figure 3 is a schematic enlarged cross-sectional view of the electronic control device 100 along the line III-III in Figure 2. Figure 4 is a schematic enlarged cross-sectional view of the electronic control device 100 along the line IV-IV in Figure 2.

[0012] The electronic control unit 100 of this embodiment is mounted on a vehicle and controls various actuators used in the vehicle's engine, transmission, etc. The electronic control unit 100 is designed to be lightweight, for example, by using resin for its components, with the aim of reducing the overall weight of the vehicle. It is also directly fixed to the engine body and transmission, and the connecting cables have been shortened.

[0013] The electronic control unit 100 includes, for example, a circuit board 110, a resin base 120, a metal cover 130, a conductive connection part 140, and a flow prevention part 150. The electronic control unit 100 also includes, for example, a sealing member 160 and a connector 170.

[0014] The circuit board 110 is a multilayer board having, for example, a target wiring 111 to be noise-reduced and an electronic component 112 mounted near the target wiring 111, as shown in Figure 2. The circuit board 110 also has, for example, a housing ground 113 provided along the edge of the circuit board 110 at its peripheral edge, and a signal ground 114 provided inside the circuit board 110 beyond the housing ground 113, as shown in Figures 2 and 3. Furthermore, the circuit board 110 has, for example, a plurality of openings 115 and a plurality of through vias 116.

[0015] The target wiring 111 is, for example, a clock wiring, power wiring, or signal wiring located on the first layer of the circuit board 110, and is paired with a signal ground 114 located on the second layer of the circuit board 110, and transmits clock, power, or signal. The electronic component 112 is, for example, a circuit element such as a capacitor, and is located as close as possible to the target wiring 111. Also, the electronic component 112 is located, for example, between the target wiring 111 and the conductive connection part 140.

[0016] The housing ground 113 is provided in multiple layers of the circuit board 110, which is a multilayer substrate, as shown in Figure 3, and the housing ground 113 provided in each layer is connected to each other by multiple through vias 116. Similarly, the signal ground 114 is provided in multiple layers of the circuit board 110, and the signal ground 114 provided in each layer is connected to each other by multiple through vias 116 and is also connected to individual circuits (not shown) provided on the circuit board 110. In addition, the signal ground 114 is connected to an electronic component 112, for example, and the housing ground 113 is connected to the signal ground 114 via an electronic component 112, for example, and is also connected to the cover 130 via a conductive connection part 140.

[0017] The opening 115 is formed, for example, by a through-hole penetrating the circuit board 110 between the conductive connection portion 140 and the electronic component 112, and penetrates the flow prevention portion 150 to be described later. The through-via 116 electrically connects, for example, the housing ground 113, the signal ground 114, etc. provided in each layer of the circuit board 110 as shown in FIGS. 2 and 3. By providing such a through-via 116, the path from the conductive connection portion 140 to the signal ground 114 of the second layer of the circuit board 110 is shortened.

[0018] The base portion 120 is, for example, a resin molded product as shown in FIG. 1, has a concave shape with an open upper part and front part, and constitutes a part of the housing that houses the circuit board 110. The base portion 120 covers the lower surface of the circuit board 110 and supports the lower surface and the periphery of the circuit board 110. Further, the base portion 120 has, for example, a plurality of leg portions 121 on both sides in the width direction. Each leg portion 121 is attached to, for example, an engine body or a transmission by bolts.

[0019] The cover 130 is, for example, a rectangular plate-like member made of metal having irregularities as shown in FIG. 1, and constitutes a part of the housing that houses the circuit board 110 together with the base portion 120. The cover 130 is fixed to the base portion 120 by inserting, for example, a fixing pin 122 provided at a corner of the base portion 120 into a through-hole 131 provided at a corner of the cover 130 and heating and expanding the tip of the pin 122, and covers the upper surface of the circuit board 110.

[0020] The conductive connection portion 140 is, for example, a conductive member that connects the housing ground 113 of the circuit board 110 and the cover 130. The conductive connection portion 140 is, for example, a conductive adhesive or conductive grease, and has fluidity at least during the assembly of the electronic control device 100. More specifically, when the cover 130 is attached to the base portion 120 with the conductive connection portion 140 disposed on the circuit board 110 supported by the base portion 120, the conductive connection portion 140 compressed between the circuit board 110 and the cover 130 flows and spreads on the circuit board 110.

[0021] The flow prevention part 150 prevents the spread of the conductive connection part 140 as described above. More specifically, the flow prevention part 150 is provided adjacent to the side surface of the conductive connection part 140 facing the target wiring 111, and prevents the flow of the conductive connection part 140 in the direction toward the target wiring 111. In the example shown in FIG. 1, the flow prevention part 150 is a convex part provided on the base part 120, and the circuit board 110 has an opening 115 penetrating the flow prevention part 150. Note that the flow prevention part 150 may be, for example, a convex part provided on the cover 130 or may be provided on the circuit board 110.

[0022] In the example shown in FIG. 1, the flow prevention part 150 has a semi-cylindrical shape. Note that the flow prevention part 150 may have, for example, a flat plate-like part extending along the edge of the circuit board 110 and an arc-like part that curves toward the edge of the circuit board 110 along the outer periphery of the circular conductive connection part 140 in a plan view at the end of the flat plate-like part. In this case, the opening 115 of the circuit board 110 has an arc-like shape corresponding to the shape of the flow prevention part 150 or a linear part and an arc-like part.

[0023] As shown in FIG. 2, the flow prevention part 150 has a communication path 151 between the conductive connection part 140 and the electronic component 112. In the example shown in FIG. 2, the flow prevention part 150 is provided adjacent to the semi-cylindrical side surface facing the target wiring 111 of the circular conductive connection part 140 in a plan view, and has a semi-cylindrical shape along the outer edge of the conductive connection part 140. The communication path 151 of the flow prevention part 150 is provided, for example, at a position between the conductive connection part 140 and the electronic component 112. Also, the communication path 151 is provided, for example, on a path where the distance between the target wiring 111 and the conductive connection part 140 is the shortest.

[0024] The housing ground 113 of the circuit board 110 has, for example, a first connection part 113a connected to a conductive connection part 140 and a second connection part 113b connected to an electronic component 112. As shown in Figure 2, the first connection part 113a is, for example, a circular pad-shaped portion in the frame-shaped housing ground 113 provided along the outer edge of the circuit board 110, corresponding to the planar shape of the conductive connection part 140. The second connection part 113b is, for example, a rectangular pad-shaped portion provided inside the frame-shaped housing ground 113 adjacent to the target wiring 111.

[0025] Furthermore, the housing ground 113 has a connecting section 113c that connects the first connection section 113a and the second connection section 113b, for example, by passing through the connecting passage 151 of the flow prevention section 150. The connecting section 113c is provided in a straight line that connects the first connection section 113a and the second connection section 113b by the shortest path. The width of the connecting section 113c is made as narrow as possible, for example, within a range that can reduce noise in the target wiring 111.

[0026] This makes it possible to narrow the width of the communication passage 151 of the flow prevention section 150 as much as possible, thereby preventing flow of the conductive connection section 140 toward the target wiring 111. Alternatively, the viscosity of the conductive connection section 140 may be appropriately set according to the width of the communication passage 151 to prevent flow of the conductive connection section 140 toward the target wiring 111. Furthermore, in order to more reliably prevent flow of the conductive connection section 140 through the communication passage 151, the flow prevention section 150 may have, for example, a shielding section 152.

[0027] The shielding portion 152 is a wall-like portion that is positioned between the conductive connection portion 140 and the communication passage 151, as shown by the dashed lines in Figures 2 and 3, and shields the path between the conductive connection portion 140 and the communication passage 151. The shielding portion 152 is provided, for example, so as to protrude from the surface of the cover 130 facing the circuit board 110 toward the circuit board 110. The shielding portion 152 may also be fixed, for example, on the first connection portion 113a or the communication portion 113c of the housing ground 113 so as to shield the communication passage 151.

[0028] The sealing member 160 has, for example, a frame-shaped portion positioned between the base portion 120 and the cover 130, and a frame-shaped portion positioned between the base portion 120 and the connector 170, as shown in Figure 1. The sealing member 160 seals the space between the base portion 120 and the cover 130, and also seals the space between the base portion 120 and the connector 170.

[0029] The connector 170 is positioned at the open front of the base portion 120 when mounted on the circuit board 110, as shown in Figure 1, and is supported from above, below, left, and right by the base portion 120 and the cover 130 via a sealing member 160. The connector 170 has a plurality of connector pins 171 connected to the circuit of the circuit board 110 and is connected to a connecting cable (not shown).

[0030] The operation of the electronic control device 100 of this embodiment will be explained below in comparison with the conventional electronic control device described in Patent Document 1 mentioned above.

[0031] As described above, in the conventional electronic control device, a convex member is placed between the conductive connection part and the electronic component, and the conductive connection part and the convex member are in contact. This prevents unnecessary spreading of the conductive material on the circuit board surface when it is placed in a predetermined position on the circuit board. Therefore, even if the component no-go zone on the circuit board is set small, contact between the conductive material and electronic components or wiring patterns on the circuit board can be prevented, thereby preventing damage to the circuit.

[0032] Such electronic control devices require suppression of emissions (EMI) and improvement of immunity (EMS), that is, further improvement of electromagnetic compatibility (EMC). However, in the conventional electronic control devices described above, the convex members act as an obstacle, making it difficult to connect the signal ground near target wiring such as clock wiring provided in the mounting area of ​​the circuit board to the housing ground near the conductive connection part connected to the metal cover. In other words, the path of the signal ground from the vicinity of the target wiring to the housing ground near the conductive connection part has to bypass the convex member, increasing the impedance of the signal ground and increasing radiated noise.

[0033] In contrast, the electronic control device 100 of this embodiment, as described above, includes a circuit board 110, a resin base portion 120 that supports the circuit board 110, and a metal cover 130 that covers the base portion 120 supported by the base portion 120. The electronic control device 100 also includes a conductive connection portion 140 that connects the cover 130 to the circuit board 110, and a flow prevention portion 150 that prevents the conductive connection portion 140 from spreading. The circuit board 110 includes target wiring 111 that is subject to noise reduction, and electronic components 112 mounted near the target wiring 111. The circuit board 110 also includes a signal ground 114 connected to the electronic components 112, and a housing ground 113 that is connected to the signal ground 114 via the electronic components 112 and also connected to the cover 130 via the conductive connection portion 140. The flow prevention portion 150 has a communication passage 151 between the conductive connection portion 140 and the electronic components 112. Furthermore, the housing ground 113 has a first connection part 113a connected to the conductive connection part 140, a second connection part 113b connected to the electronic component 112, and a connecting part 113c that connects the first connection part 113a and the second connection part 113b through the connecting passage 151 of the flow prevention part 150.

[0034] With this configuration, the electronic control device 100 of this embodiment can connect the signal ground 114 near the target wiring 111 to the housing ground 113 connected to the cover 130 via the conductive connection part 140, without bypassing the flow prevention part 150. More specifically, the first connection part 113a of the housing ground 113 connected to the conductive connection part 140 and the second connection part 113b of the housing ground 113, which is connected to the signal ground 114 near the target wiring 111 via the electronic component 112, are connected by a contact part 113c of the housing ground 113. This contact part 113c passes through a contact passage 151 of the flow prevention part 150 provided between the conductive connection part 140 and the electronic component 112.

[0035] Therefore, the path from the first connection part 113a of the housing ground 113 connected to the conductive connection part 140 to the second connection part 113b of the housing ground 113 connected to the signal ground 114 near the target wiring 111 via the electronic component 112 is shortened. As a result, the electronic control device 100 can prevent unnecessary spreading of the conductive connection part 140 with the flow prevention part 150, while reducing the impedance of the path between the metal cover 130 and the signal ground 114 near the target wiring 111. More specifically, the electronic control device 100 of this embodiment can reduce the impedance of the above path by about 75% at frequencies of 100 MHz or higher, where parasitic inductance becomes dominant, compared to the conventional electronic control device described above.

[0036] In this way, the signal ground 114, which is the return path of the target wiring 111 that is a noise source, is connected to the cover 130 with low impedance via electronic components 112 such as capacitors or capacitors, the housing ground 113, the through-via 116, and the conductive connection part 140. As a result, the signal ground 114 can be stabilized and the generation of common-mode noise in the target wiring 111 can be suppressed. Therefore, according to the electronic control device 100 of this embodiment, it is possible to suppress radiated noise and improve EMC while preventing the conductive connection part 140 from spreading unnecessarily on the surface of the circuit board 110.

[0037] Furthermore, in the electronic control device 100 of this embodiment, the communication passage 151 of the flow prevention unit 150 is provided on a path that minimizes the distance between the target wiring 111 and the conductive connection unit 140. With this configuration, the length of the communication unit 113c connecting the first connection unit 113a, which is connected to the conductive connection unit 140, and the second connection unit 113b, which is connected to the electronic component 112, can be minimized. Therefore, according to the electronic control device 100 of this embodiment, the impedance of the path between the metal cover 130 and the signal ground 114 near the target wiring 111 can be further reduced, and the EMC can be further improved.

[0038] Furthermore, in the electronic control device 100 of this embodiment, the flow prevention portion 150 is a protrusion provided on the base portion 120, and the circuit board 110 has an opening 115 through which the flow prevention portion 150 passes. With this configuration, it becomes possible to integrally mold the resin base portion 120 and the flow prevention portion 150, and the flow prevention portion 150 having electrical insulating properties can be easily formed. In addition, when placing the circuit board 110 on the base portion 120, the flow prevention portion 150 can be inserted through the opening 115 of the circuit board 110, allowing the circuit board 110 to be positioned relative to the base portion 120, thereby improving the ease of assembly of the electronic control device 100.

[0039] Furthermore, as described above, the electronic control device 100 of this embodiment may have a shielding portion 152 positioned between the conductive connection portion 140 and the communication passage 151 of the flow prevention portion 150, which shields the path between the conductive connection portion 140 and the communication passage 151. With this configuration, the shielding portion 152 prevents the conductive connection portion 140 from entering or passing through the communication passage 151, thereby more reliably preventing the conductive connection portion 140 from unnecessarily expanding.

[0040] As described above, according to this embodiment, it is possible to provide an electronic control device 100 that can improve EMC while preventing the conductive connection portion 140 from unnecessarily spreading on the surface of the circuit board 110. Note that the electronic control device according to this disclosure is not limited to the configuration of the electronic control device 100 according to the above-described embodiment. Hereinafter, modifications of the electronic control device 100 according to the above-described embodiment will be described with reference to Figures 5 and 6.

[0041] Figure 5 is a schematic enlarged view showing a modified example 1 of the electronic control device 100 of Figure 2. In the electronic control device 100 according to this modified example, the conductive connection portion 140 has a dimension in the direction along the edge of the circuit board 110 that is larger than the dimension in the direction intersecting the edge of the circuit board 110. More specifically, the conductive connection portion 140 has an oval planar shape having a straight portion extending along the edge of the circuit board 110 and semicircular ends at both ends of the straight portion. This configuration increases the contact area between the conductive connection portion 140 and the housing ground 113 and cover 130, making it possible to further reduce the impedance between the housing ground 113 and cover 130.

[0042] Furthermore, in the modified electronic control device 100, the flow prevention portion 150 has a length that extends beyond both ends of the conductive connection portion 140 in the direction along the edge of the circuit board 110. Also, the length of each opening 115 of the circuit board 110 along the conductive connection portion 140 is 15 mm or less. With this configuration, the frequency of the slit radiation generated according to the length of the opening 115 of the circuit board 110 can be shifted to a frequency of 6 GHz or higher, for which no EMI standards have been set.

[0043] Figure 6 is a schematic enlarged view showing a modified example 2 of the electronic control device 100 of Figure 2. In this modified example, the electronic control device 100 has two conductive connection parts 140 arranged adjacent to each other along one edge of the circuit board 110. The flow prevention part 150 is positioned between the two conductive connection parts 140 and the electronic component 112 and has a connecting passage 151 between the two conductive connection parts 140. The housing ground 113 has two first connection parts 113a connected to the two conductive connection parts 140, and a connecting part 113c that passes through the connecting passage 151 and connects the portion between the two first connection parts 113a and the second connection part 113b. This configuration can also achieve the same effects as the electronic control device 100 according to the above embodiment.

[0044] While embodiments of the electronic control device relating to this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design changes, etc., that do not depart from the gist of this disclosure are also included in this disclosure.

[0045] For example, in the embodiment of the electronic control device described above, the shape of the flow prevention part was a shape having arc-shaped parts at both ends of a straight section, or a semi-cylindrical shape. However, the shape of the flow prevention part can be any shape, such as a channel shape or a rectangular U-shape with one end open, a straight shape, or a shape with multiple pins arranged in a straight line. The flow prevention part may also have ribs to improve moldability. [Explanation of Symbols]

[0046] 100 Electronic control unit 110 Circuit board 111 Target wiring 112 Electronic Components 113 Grand Cabinet 113a First connection section 113b Second connection section 113c Liaison Office 114 Signal Ground 115 Opening 120 Base section 130 Cover 140 Conductive connection part 150 Flow prevention part 151 Connecting passage 152 Shielding part

Claims

1. An electronic control device comprising: a circuit board on which wiring is provided; a resin base portion supporting the circuit board; a metal cover covering the circuit board supported by the base portion; a conductive connection portion connecting the cover to the circuit board; and a flow prevention portion disposed between the conductive connection portion and the wiring, The circuit board has a signal ground connected to an electronic component mounted between the wiring and the flow prevention part, and a housing ground connected to the signal ground via the electronic component and connected to the cover via the conductive connection part. The aforementioned wiring is paired with the signal ground and is used to transmit clock, power, or signal. The flow prevention section has a connecting passage on the path that minimizes the distance between the wiring and the conductive connection section. The housing gland has a first connection portion connected to the conductive connection portion, a second connection portion connected to the electronic component, and a connecting portion that connects the first connection portion and the second connection portion through the communication passage of the flow prevention portion. The flow prevention portion is a protrusion provided on the base portion, The circuit board has an opening that penetrates the flow prevention portion, The conductive connection portion has a dimension in the direction along the edge of the circuit board that is greater than the dimension in the direction intersecting the edge of the circuit board. An electronic control device characterized by the following features.

2. The flow prevention portion has a length that extends beyond both ends of the conductive connection portion in the direction along the edge of the circuit board, The electronic control device according to claim 1, characterized in that the opening of the circuit board has a length of 15 mm or less along the flow prevention portion.

3. An electronic control device comprising: a circuit board on which wiring is provided; a resin base portion supporting the circuit board; a metal cover covering the circuit board supported by the base portion; a conductive connection portion connecting the cover to the circuit board; and a flow prevention portion disposed between the conductive connection portion and the wiring, The circuit board has a signal ground connected to an electronic component mounted between the wiring and the flow prevention part, and a housing ground connected to the signal ground via the electronic component and connected to the cover via the conductive connection part. The aforementioned wiring is paired with the signal ground and is used to transmit clock, power, or signal. The flow prevention section has a connecting passage on the path that minimizes the distance between the wiring and the conductive connection section. The housing gland has a first connection portion connected to the conductive connection portion, a second connection portion connected to the electronic component, and a connecting portion that connects the first connection portion and the second connection portion through the communication passage of the flow prevention portion. An electronic control device characterized by having a shielding portion disposed between the conductive connection portion and the communication passage of the flow prevention portion, which shields the path between the conductive connection portion and the communication passage.

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