JP2024018046A - electronic control unit - Google Patents

Abstract

The present disclosure provides an electronic control device that can improve electromagnetic compatibility while preventing conductive connections from spreading unnecessarily on the surface of a circuit board. An electronic control device includes a circuit board 110, a resin base part 120, a metal cover, a conductive connection part 140, and a flow prevention part 150. The circuit board 110 includes a target wiring 111 to be subjected to noise reduction, an electronic component 112 mounted near the target wiring 111, a signal ground 114 connected to the electronic component 112, and a signal ground 114 connected to the electronic component 112 via the electronic component 112. and a housing ground 113 connected to the signal ground 114 and connected to the cover via a conductive connection part 140. The flow 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 second connection between the first connection part 113a and the second connection part through the communication passage 151. It has a communication part 113c that connects with the part 113b. [Selection diagram] Figure 2

Description

The present disclosure relates to an electronic control device.

Electronic control devices have been known for a long time. 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 grounding circuit between the metal cover and the circuit board. and a conductive connection portion that conductively connects the. In this electronic control device, the circuit board is sandwiched between the base and the metal cover, a convex member is arranged between the conductive connection part and the electronic component, and the circuit board is sandwiched between the conductive connection part and the electronic component. It is characterized in that the convex member is in contact with the above-mentioned convex member (Patent Document 1, paragraph 0011, claim 1).

According to this conventional electronic control device, when installing a conductive material at a predetermined position on a circuit board, it is possible to prevent unnecessary spreading of the conductive material on the circuit board surface. Therefore, even if the prohibited component zone on the circuit board is set small, it is possible to prevent the conductive material from coming into contact with electronic components or wiring patterns on the circuit board, and damage to the circuit can be prevented (Patent Document 1 , paragraph 0012).

International Publication No. 2022/059263

In electronic control devices such as those described above, suppression of emissions (EMI) and improvement of immunity (EMS), that is, further improvement of electromagnetic compatibility (EMC) are required. However, as mentioned above, in the conventional electronic control device, a convex member is placed between the conductive connection part and the electronic component to prevent unnecessary spread of the conductive material on the circuit board surface. However, the convex member may become an obstacle to improving EMC.

The present disclosure provides an electronic control device that can improve EMC while preventing conductive connections from spreading unnecessarily on the surface of a circuit board.

One aspect of the present disclosure includes a circuit board, a resin base portion supporting the circuit board, a metal cover covering the circuit board supported by the base portion, and connecting the cover to the circuit board. An electronic control device having a conductive connecting portion that prevents the conductive connecting portion from spreading, and a flow prevention portion that prevents the conductive connecting portion from spreading, the circuit board comprising a target wiring that is a target for noise reduction, and a flow prevention unit that prevents the conductive connecting portion from spreading. An electronic component mounted nearby, a signal ground connected to the electronic component, and a casing connected to the signal ground via the electronic component and to the cover via the conductive connection part. a ground, the flow prevention part has a communication path between the conductive connection part and the electronic component, and the case ground has a first connection connected to the conductive connection part. a second connection part connected to the electronic component; and a communication part passing through the communication passage of the flow prevention part and connecting the first connection part and the second connection part. This is an electronic control device.

According to the above aspect of the present disclosure, it is possible to provide an electronic control device that can improve EMC while preventing the conductive connection portion from spreading unnecessarily on the surface of the circuit board.

FIG. 1 is an exploded perspective view showing an embodiment of an electronic control device according to the present disclosure. FIG. 2 is a schematic enlarged plan view of a base portion and a peripheral portion of a circuit board of the electronic control device shown in FIG. 1; FIG. 3 is a schematic enlarged sectional view of the electronic control device taken along line III-III in FIG. 2; FIG. 3 is a schematic enlarged cross-sectional view of the electronic control device taken along line IV-IV in FIG. 2; FIG. 3 is a schematic enlarged plan view showing a modification of the electronic control device shown in FIG. 2; FIG. 3 is a schematic enlarged plan view showing a modification of the electronic control device shown in FIG. 2;

Hereinafter, embodiments of an electronic control device according to the present disclosure will be described with reference to the drawings.

FIG. 1 is an exploded perspective view showing an embodiment of an electronic control device according to the present disclosure. FIG. 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 FIG. FIG. 3 is a schematic enlarged sectional view of the electronic control device 100 taken along line III-III in FIG. FIG. 4 is a schematic enlarged sectional view of the electronic control device 100 taken along line IV-IV in FIG.

The electronic control device 100 of this embodiment is mounted on a vehicle, for example, and controls various actuators used in the vehicle's engine, transmission, and the like. For example, the electronic control device 100 is being made lighter by using plastic parts for the purpose of reducing the weight of the entire vehicle, and is also being directly fixed to the engine body or the transmission to shorten the length of connection cables. ing.

The electronic control device 100 includes, for example, a circuit board 110, a base portion 120 made of resin, a cover 130 made of metal, a conductive connection portion 140, and a flow prevention portion 150. Further, the electronic control device 100 includes, for example, a seal member 160 and a connector 170.

For example, as shown in FIG. 2, the circuit board 110 is a multilayer board that includes a target wiring 111 to be subjected to noise reduction and an electronic component 112 mounted near the target wiring 111. Further, as shown in FIGS. 2 and 3, for example, the circuit board 110 has a case ground 113 provided along the edge of the circuit board 110 at the periphery of the circuit board 110, and It also has a signal ground 114 provided inside the circuit board 110. Further, the circuit board 110 includes, for example, a plurality of openings 115 and a plurality of through vias 116.

The target wiring 111 is, for example, a clock wiring, a power supply wiring, or a signal wiring placed on the first layer of the circuit board 110, and forms a pair with the signal ground 114 placed on the second layer of the circuit board 110. transmit clocks, power, or signals. The electronic component 112 is, for example, a circuit element such as a capacitor, and is placed as close as possible to the target wiring 111. Moreover, the electronic component 112 is arranged, for example, at a position between the target wiring 111 and the conductive connection part 140.

For example, as shown in FIG. 3, the case ground 113 is provided in multiple layers of the circuit board 110, which is a multilayer board, and the case grounds 113 provided in each layer are connected to each other by a plurality of through vias 116. There is. Similarly, the signal ground 114 is provided, for example, in multiple layers of the circuit board 110, and the signal grounds 114 provided in each layer are connected to each other by a plurality of through vias 116. Connected to individual circuits to omit. Further, the signal ground 114 is connected to the electronic component 112, for example, and the housing ground 113 is connected to the signal ground 114 via the electronic component 112, and to the cover 130 via the conductive connection part 140. It is connected.

The opening 115 is formed between the conductive connection part 140 and the electronic component 112 by, for example, a through hole penetrating the circuit board 110, and penetrates a flow prevention part 150, which will be described later. The through via 116 electrically connects the case ground 113, the signal ground 114, etc. provided in each layer of the circuit board 110, for example, 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 in the second layer of the circuit board 110 is shortened.

For example, as shown in FIG. 1, the base portion 120 is a resin molded product, has a concave shape with an open top and front, and constitutes a part of a casing that accommodates the circuit board 110. The base portion 120 covers the lower surface of the circuit board 110 and supports the lower surface and peripheral edge 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 121 is attached to the engine body, transmission, etc., for example, with bolts.

For example, as shown in FIG. 1, the cover 130 is a metal rectangular plate-like member having unevenness, and forms part of a casing that houses the circuit board 110 together with the base portion 120. For example, the cover 130 can be made by inserting 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 the tip of the pin 122 to enlarge the diameter. It is fixed to the base part 120 by a screwdriver, and covers the upper surface of the circuit board 110.

The conductive connection portion 140 is, for example, a conductive member that connects the case 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 when the electronic control device 100 is assembled. More specifically, when the cover 130 is attached to the base part 120 with the conductive connection part 140 disposed on the circuit board 110 supported by the base part 120, compression occurs between the circuit board 110 and the cover 130. The conductive connection portion 140 flows and spreads on the circuit board 110.

The flow prevention part 150 prevents the conductive connection part 140 from spreading 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 conductive connection part 140 from flowing 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 that allows the flow prevention part 150 to pass through. Note that the flow prevention portion 150 may be a convex portion provided on the cover 130 or may be provided on the circuit board 110, for example.

In the example shown in FIG. 1, the flow prevention part 150 has a semi-cylindrical shape. Note that the flow prevention portion 150 includes, for example, a flat portion extending along the edge of the circuit board 110 and an edge portion of the flat portion along the outer periphery of the conductive connection portion 140, which is circular in plan view. It may also have an arcuate portion that curves toward the edge of the circuit board 110. In this case, the opening 115 of the circuit board 110 has an arcuate shape or a linear portion corresponding to the shape of the flow prevention portion 150 and an arcuate portion.

As shown in FIG. 2, the flow prevention section 150 has a communication passage 151 between the conductive connection section 140 and the electronic component 112. In the example shown in FIG. 2, the flow prevention part 150 is provided adjacent to the semicylindrical side surface of the conductive connection part 140, which is circular in plan view and faces the target wiring 111, and is attached to the outer edge of the conductive connection part 140. It has a semi-cylindrical shape. The communication passage 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. Furthermore, the communication path 151 is provided, for example, on a route where the distance between the target wiring 111 and the conductive connection portion 140 is the shortest.

The case ground 113 of the circuit board 110 has, for example, a first connection part 113a connected to the conductive connection part 140 and a second connection part 113b connected to the electronic component 112. As shown in FIG. 2, the first connection portion 113a is formed into a circular shape corresponding to the planar shape of the conductive connection portion 140, for example, in the frame-shaped case ground 113 provided along the outer periphery of the circuit board 110. It is an expanded pad-like part. Further, the second connection portion 113b is, for example, a rectangular pad-shaped portion provided adjacent to the target wiring 111 inside the frame-shaped case ground 113.

Furthermore, the housing ground 113 includes, for example, a communication portion 113c that passes through the communication passage 151 of the flow prevention portion 150 and connects the first connection portion 113a and the second connection portion 113b. The communication portion 113c is provided, for example, in a straight line that connects the first connection portion 113a and the second connection portion 113b via the shortest path. For example, the width of the communication portion 113c is made as narrow as possible within a range that can reduce the noise of the target wiring 111.

Thereby, the width of the communication passage 151 of the flow prevention part 150 can be made as narrow as possible, and the flow of the conductive connection part 140 toward the target wiring 111 can be prevented. Note that the conductive connector 140 may be prevented from flowing toward the target wiring 111 by appropriately setting the viscosity of the conductive connector 140 depending on the width of the communication path 151. Further, in order to more reliably prevent the conductive connection portion 140 from flowing through the communication passage 151, the flow prevention portion 150 may include a shielding portion 152, for example.

For example, the shielding part 152 is disposed between the conductive connection part 140 and the communication passage 151, as shown by the two-dot chain line in FIGS. It is a wall-like part that blocks the route. The shielding portion 152 is provided, for example, so as to protrude toward the circuit board 110 from the surface of the cover 130 that faces the circuit board 110 . In addition. For example, the shielding part 152 may be fixed on the first connection part 113a or the communication part 113c of the housing ground 113 so as to shield the communication passage 151.

For example, as shown in FIG. 1, the sealing member 160 includes a frame-shaped portion disposed between the base portion 120 and the cover 130 and a frame-shaped portion disposed between the base portion 120 and the connector 170. It has The seal member 160 seals between the base portion 120 and the cover 130 and also seals between the base portion 120 and the connector 170.

For example, as shown in FIG. 1, the connector 170 is attached to the circuit board 110 and is disposed in the open front part of the base part 120, and is connected to the base part 120 and the cover 130 through the sealing member 160. Supported by The connector 170 has a plurality of connector pins 171 connected to circuits on the circuit board 110, and is connected to a connection cable (not shown).

Hereinafter, the operation of the electronic control device 100 of this embodiment will be explained based on comparison with the conventional electronic control device described in Patent Document 1 mentioned above.

As described above, in the conventional electronic control device, the 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. Thereby, when installing the conductive material at a predetermined position on the circuit board, unnecessary spreading on the surface of the circuit board can be prevented. Therefore, even if the component prohibited zone on the circuit board is set small, it is possible to prevent the conductive material from coming into contact with electronic components or wiring patterns on the circuit board, and damage to the circuit can be prevented.

In such electronic control devices, suppression of emissions (EMI) and improvement of immunity (EMS), that is, further improvement of electromagnetic compatibility (EMC) are required. However, in the conventional electronic control device described above, the convex member becomes an obstacle, and the signal ground near the target wiring such as the clock wiring provided in the mounting area of the circuit board is connected to the conductive connection part connected to the metal cover. It becomes difficult to connect to the nearby chassis ground. That is, the path of the signal ground from the vicinity of the target wiring to the case ground near the conductive connection becomes a path that detours around the convex member, increasing the impedance of the signal ground and increasing radiation noise.

On the other hand, as described above, the electronic control device 100 of the present embodiment includes a circuit board 110, a resin base part 120 that supports the circuit board 110, and a base part 120 that is supported by the base part 120. It has a metal cover 130 that covers the. Further, the electronic control device 100 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 a target wiring 111 to be subjected to noise reduction, and an electronic component 112 mounted near the target wiring 111. The circuit board 110 also includes a signal ground 114 connected to the electronic component 112 and a housing ground connected to the signal ground 114 via the electronic component 112 and to the cover 130 via a conductive connection part 140. 113. The flow prevention section 150 has a communication passage 151 between the conductive connection section 140 and the electronic component 112. Furthermore, the case ground 113 passes through 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 passage 151 of the flow prevention part 150. It has a connecting part 113c that connects the connecting part 113a and the second connecting part 113b.

With such a configuration, the electronic control device 100 of the present embodiment connects the signal ground 114 near the target wiring 111 to the cover 130 via the conductive connection part 140 without bypassing the flow prevention part 150. It can be connected to the housing ground 113. More specifically, the first connection portion 113a of the case ground 113 is connected to the conductive connection portion 140, and the first connection portion 113a of the case ground 113 is connected to the signal ground 114 via the electronic component 112 near the target wiring 111. The second connecting portion 113b is connected to the connecting portion 113c of the housing ground 113. This communication portion 113c passes through a communication passage 151 of a flow prevention portion 150 provided between the conductive connection portion 140 and the electronic component 112.

Therefore, a second connection of the casing ground 113 is connected from the first connection part 113a of the casing ground 113 connected to the conductive connection part 140 to the signal ground 114 near the target wiring 111 via the electronic component 112. The route to the portion 113b is shortened. As a result, the electronic control device 100 prevents unnecessary expansion of the conductive connection portion 140 by the flow prevention portion 150, and reduces the impedance of the path between the metal cover 130 and the signal ground 114 near the target wiring 111. can be lowered. More specifically, the electronic control device 100 of the present embodiment reduces the impedance of the path by about 75% at a frequency of 100 MHz or higher where parasitic inductance is dominant, for example, compared to the conventional electronic control device described above. It becomes possible to reduce the amount.

In this way, the signal ground 114, which is the return path of the target wiring 111, which is a noise source, is connected to the cover 130 via the capacitor or the electronic component 112 such as the capacitor, the case ground 113, the through via 116, and the conductive connection part 140. connected with low impedance. As a result, the signal ground 114 can be stabilized, and the occurrence 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 prevent the conductive connection portion 140 from spreading unnecessarily on the surface of the circuit board 110, suppress radiation noise, and improve EMC.

Furthermore, in the electronic control device 100 of this embodiment, the communication passage 151 of the flow prevention section 150 is provided on the path where the distance between the target wiring 111 and the conductive connection section 140 is the shortest. With such a configuration, the length of the communication part 113c that passes through the communication passage 151 and connects the first connection part 113a connected to the conductive connection part 140 and the second connection part 113b connected to the electronic component 112 is reduced. can be made as short as possible. 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 EMC can be further improved.

Furthermore, in the electronic control device 100 of the present embodiment, the flow prevention part 150 is a convex part provided on the base part 120, and the circuit board 110 has an opening 115 that allows the flow prevention part 150 to pass through. . With such a configuration, the base portion 120 made of resin and the flow prevention portion 150 can be integrally molded, and the flow prevention portion 150 having electrical insulation properties can be easily formed. Further, when placing the circuit board 110 on the base part 120, the flow prevention part 150 can be inserted into the opening 115 of the circuit board 110, and the circuit board 110 can be positioned with respect to the base part 120. 100, the ease of assembly is improved.

Further, as described above, the electronic control device 100 of the present embodiment is arranged between the conductive connection part 140 and the communication passage 151 of the flow prevention part 150, and is arranged between the conductive connection part 140 and the communication passage 151 of the flow prevention part 150. It is possible to have a shielding part 152 that shields the path. With this configuration, the shielding part 152 can prevent the conductive connection part 140 from entering or passing through the communication passage 151, thereby more reliably preventing the conductive connection part 140 from spreading unnecessarily. It becomes possible.

As described above, according to the present embodiment, it is possible to provide the electronic control device 100 that can improve EMC while preventing the conductive connection portion 140 from spreading unnecessarily on the surface of the circuit board 110. I can do it. Note that the electronic control device according to the present disclosure is not limited to the configuration of the electronic control device 100 according to the above-described embodiment. Hereinafter, a modification of the electronic control device 100 according to the above-described embodiment will be described with reference to FIGS. 5 and 6.

FIG. 5 is a schematic enlarged view showing a first modification of the electronic control device 100 of FIG. In the electronic control device 100 according to this modification, the dimension of the conductive connection portion 140 in the direction along the edge of the circuit board 110 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 line portion extending along the edge of the circuit board 110 and semicircular end portions at both ends of the straight line portion. ing. Such a configuration makes it possible to increase the contact area between the conductive connection portion 140, the case ground 113, and the cover 130, and further reduce the impedance between the case ground 113 and the cover 130.

Furthermore, in the electronic control device 100 according to the present modification, the flow prevention section 150 has a length extending to the outside of both ends of the conductive connection section 140 in the direction along the edge of the circuit board 110. Further, each of the openings 115 of the circuit board 110 has a length along the conductive connection portion 140 of 15 mm or less. With such a configuration, it is possible to shift the frequency of slit radiation generated depending on the length of the opening 115 of the circuit board 110 to a frequency of 6 GHz or higher for which no EMI standard is set.

FIG. 6 is a schematic enlarged view showing a second modification of the electronic control device 100 of FIG. In the electronic control device 100 according to this modification, two conductive connection parts 140 are arranged adjacent to each other along one edge of the circuit board 110. Further, the flow prevention section 150 is arranged between the two conductive connection sections 140 and the electronic component 112, and has a communication passage 151 between the two conductive connection sections 140. The housing ground 113 connects the two first connection parts 113a connected to the two conductive connection parts 140, and the part between the two first connection parts 113a through the communication passage 151 and the second connection part 113b. It has a connecting portion 113c for connection. Such a configuration can also provide the same effects as the electronic control device 100 according to the above-described embodiment.

Although the embodiment of the electronic control device according to the present disclosure has been described above in detail using the drawings, the specific configuration is not limited to this embodiment, and design changes may be made within the scope of the gist of the present disclosure. etc., they are included in the present disclosure.

For example, in the embodiments of the electronic control device described above, the shape of the flow prevention part is a shape in which a linear part has arcuate parts at both ends, or a semi-cylindrical shape. However, the shape of the flow prevention part may be any shape, such as a channel shape with one end open, a square U-shape, a linear shape, or a shape in which a plurality of pins are arranged in a straight line. I can do it. Moreover, the flow prevention part may have ribs for improving moldability.

100 Electronic control device 110 Circuit board 111 Target wiring 112 Electronic component 113 Housing ground 113a First connection part 113b Second connection part 113c Communication part 114 Signal ground 115 Opening part 120 Base part 130 Cover 140 Conductive connection part 150 Flow prevention part 151 Communication passage 152 Shielding part

Claims (7)

a circuit board, a resin base part that supports the circuit board, a metal cover that covers the circuit board supported by the base part, and a conductive connection part that connects the cover to the circuit board; An electronic control device comprising a flow prevention part that prevents the conductive connection part from spreading,
The circuit board includes a target wiring to be subjected to noise reduction, an electronic component mounted near the target wiring, a signal ground connected to the electronic component, and a connection to the signal ground via the electronic component. and a housing ground connected to the cover via the conductive connection part,
The flow prevention part has a communication passage between the conductive connection part and the electronic component,
The case ground passes through a first connection part connected to the conductive connection part, a second connection part connected to the electronic component, and the communication passage of the flow prevention part and connects to the first connection part. An electronic control device comprising: a communication section that connects the second connection section. 2. The electronic control device according to claim 1, wherein the communication path is provided on a path where the distance between the target wiring and the conductive connection portion is the shortest. The flow prevention part is a convex part provided on the base part,
The electronic control device according to claim 2, wherein the circuit board has an opening that penetrates the flow prevention part. 4. The electronic control device according to claim 3, wherein a dimension of the conductive connection portion in a direction along an edge of the circuit board is larger than a dimension in a direction intersecting the edge of the circuit board. . The flow prevention part has a length extending to the outside of both ends of the conductive connection part in a direction along the edge of the circuit board,
5. The electronic control device according to claim 4, wherein the opening of the circuit board has a length along the flow prevention part of 15 mm or less. Claim 2, further comprising a shielding part that is disposed between the conductive connection part and the communication passage of the flow prevention part and blocks a path between the conductive connection part and the communication passage. The electronic control device described in . two of the conductive connections are arranged adjacently along one edge of the circuit board;
The flow prevention part is disposed between the two conductive connection parts and the electronic component, and has the communication passage between the two conductive connection parts,
The case ground includes the two first connection portions connected to the two conductive connection portions, a portion passing through the communication passage between the two first connection portions, and the second connection portion. 2. The electronic control device according to claim 1, further comprising: the communication section that connects the electronic control device.

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