Electronic control device and method of wiring ground lines

Abstract

The electronic control device includes multiple boards for transmitting signals to each other and a power connector for DC power. Furthermore, a grounding wire connected to the grounding terminal of the power connector is connected to the grounding terminals of other boards via one grounding terminal of each board. This simplifies the wiring of the grounding wire in an electronic control device with multiple boards and reduces the number of noise-handling components.

Description

Technical Field

[0001] This invention relates to an electronic control device with multiple built-in substrates and a grounding wire wiring method. Background Technology

[0002] In electronic control devices with multiple built-in substrates, it is necessary to connect the ground terminal of the DC power supply to each substrate. As a method for connecting the ground terminal of the DC power supply to each substrate, as described in Japanese Patent Application Publication No. 2019-187077 (Patent Document 1), a technique is proposed in which the ground wire is branched inside a connector that allows the DC power supply wiring harness to be detached and connected, and then connected to the ground terminal of each substrate.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-187077 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, noise mitigation components such as capacitors need to be installed at the connection points of the grounding wire relative to the substrate. In technologies where the grounding wire branches internally within the connector to connect to each substrate, there are multiple connection points between the grounding wire and the substrate, and noise mitigation components must be installed at each connection point. In this case, the wiring of the grounding wire in the electronic control device becomes complex, and the installation of noise mitigation components leads to a reduction in the actual installation space.

[0008] Therefore, the object of the present invention is to provide an electronic control device and a grounding wire wiring method that makes grounding wire wiring easier and reduces noise response components.

[0009] Technical solutions for solving technical problems

[0010] The electronic control device includes multiple substrates for transmitting signals to each other and a power connector for DC power. Furthermore, a ground wire connected to the ground wire of the power connector is connected to the ground terminals of other substrates via a ground terminal of one of the multiple substrates.

[0011] Beneficial effects

[0012] According to the present invention, in an electronic control device with multiple built-in substrates, the wiring of grounding wires can be made easier, and the noise response components can be reduced. Attached Figure Description

[0013] Figure 1 This is a three-dimensional diagram representing an example of a power steering system.

[0014] Figure 2 This is a perspective view representing an example of a motor unit.

[0015] Figure 3 This is a perspective view showing an example of the internal structure of an electronic control device.

[0016] Figure 4 This is a plan view representing an example of a connector unit.

[0017] Figure 5 This is a plan view showing an example of electronic components mounted on the surface of a power supply board.

[0018] Figure 6 This is a plan view showing an example of electronic components mounted on the surface of a control substrate.

[0019] Figure 7 This is a plan view showing an example of electronic components mounted on the back of a control board.

[0020] Figure 8 This is a longitudinal sectional view showing an example of the wiring layout for the grounding wire.

[0021] Figure 9 This is a longitudinal sectional view showing an example of a supply path from the power supply terminal to the control board for supplying power voltage.

[0022] Figure 10 This is a longitudinal sectional view showing a first embodiment of a line configuration for noise reduction.

[0023] Figure 11 This is a longitudinal sectional view showing a second embodiment of the line configuration for noise reduction.

[0024] Figure 12 This is a longitudinal sectional view showing a third embodiment of the line configuration for noise reduction.

[0025] Figure 13 This is a schematic circuit diagram representing an example of the control system of an electric steering system.

[0026] Figure 14 This is an illustration of the path of current flow at the grounding terminal when the grounding terminal of the second system is disconnected.

[0027] Figure 15 This is a longitudinal sectional view showing other examples of grounding wire wiring layouts. Detailed Implementation

[0028] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

[0029] Figure 1This illustrates one example of an embodiment, namely an electric power steering system 100 installed in vehicles such as passenger cars, buses, trucks, and construction machinery.

[0030] The electric power steering system 100 includes a rack and pinion steering gearbox 200 and a motor unit 300 that assists the driver's steering wheel operation force.

[0031] The steering gearbox 200 includes: an input shaft 210 connected to the steering wheel via a steering shaft; a pinion (not shown) fixed to the front end of the input shaft 210; a rack (not shown) extending in the left-right direction and meshing with the pinion; and a gear housing 220 housing the pinion and rack. A tie rod 230 is connected to each end of the rack, and a ball joint 240, which connects to the steering knuckle arm, is connected to the front end of the tie rod 230. Furthermore, rubber sleeves 250, which can extend and retract in the left-right direction, are installed at both ends of the gear housing 220 to prevent rainwater, dust, and other foreign objects from entering. Additionally, a torque sensor 260, which detects the driver's steering wheel input force (steering torque), is installed in the middle of the input shaft 210.

[0032] At a designated location on the gear housing 220, a mounting portion 270 for mounting the motor unit 300 is formed, with the axis of the motor unit 300 being substantially parallel to the axis of the gear housing 220. For example, the mounting portion 270 is formed on a protruding surface that extends along the shape of the mating surface of the motor unit 300, and a reducer and a ball nut gear (not shown) are disposed therein to reduce the rotational driving force of the motor unit 300 and transmit it to the rack.

[0033] like Figure 2 As shown, the motor unit 300 includes: a motor 320, which may be a brushed motor, a brushless motor, etc.; and an electronic control unit 340, which has built-in electronic circuitry for controlling and driving the motor 320. The electronic control unit 340 is integrally mounted on the back of the motor 320, that is, on the back side opposite to the mating surface of the steering gearbox 200. Furthermore, the output shaft 322 of the motor 320 transmits rotational driving force to the rack via a reducer and a ball nut gear disposed in the mounting portion 270 of the gear housing 220. It should be noted that the electronic control unit 340 can be separated from the motor unit 300.

[0034] The motor 320 of the motor unit 300 includes: a stator (not shown) having coils of two systems; a rotor (not shown) integrated with the output shaft 322; and a housing 324 that houses the stator and rotor. Therefore, the motor 320 of the motor unit 300 is driven by at least one of the coils of the two systems, and can provide assistance to the driver's steering wheel operation force even if one of the coils of the two systems fails.

[0035] like Figures 2 to 4 As shown, the electronic control device 340 of the motor unit 300 includes: a power supply board 350 and a control board 360 for transmitting signals to each other; a connector unit 370 for supplying DC power and control signals to the power supply board 350 and the control board 360; and a cover 380 for housing the power supply board 350 and the control board 360. Here, the power supply board 350 and the control board 360 are connected, for example, via wires, flexible cables, or B-to-B connectors (board-to-board connectors) to transmit arbitrary signals to each other. Furthermore, the power supply board 350 and the control board 360 are detachably connected to bosses 324A and 324B formed on the bottom wall of the housing 324 of the motor 320 using screws 326.

[0036] like Figure 5 As shown, to achieve a redundant structure, a smoothing circuit 350A and an inverter circuit 350B for the first system, and a smoothing circuit 350C and an inverter circuit 350D for the second system are mounted on the surface of the power supply board 350. Figure 6 and Figure 7 As shown, to achieve a redundant structure, the control board 360 is equipped with: a microcomputer 360A, a power supply circuit 360B, and an inverter drive signal generation circuit 360C for the first system; and a microcomputer 360D, a power supply circuit 360E, and an inverter drive signal generation circuit 360F for the second system. Furthermore, the inverter drive signal generation circuits 360C and 360F of the control board 360 are configured to supply drive signals to the inverter circuits 350B and 350D of the power supply board 350 via a bus (not shown).

[0037] The connector unit 370 includes: a power connector 370A, which is detachably connected to a DC power supply harness for a first system; a power connector 370B, which is detachably connected to a DC power supply harness for a second system; and a control connector 370C, which is detachably connected to a harness for transmitting control signals between the first and second systems. The power connector 370A for the first system, the power connector 370B for the second system, and the control connector 370C are, for example, integrally and vertically mounted on one side of a flat connector base 370D.

[0038] The cover 380 is a bottomed cylindrical shape with an opening at one end along the axial direction. The open end is pressed into and fixed to a groove formed on the outer peripheral surface of the housing 324 of the motor 320. Furthermore, openings are formed along the outer shape of the bottom wall of the cover 380, such that the power connector 370A of the first system, the power connector 370B of the second system, and the control connector 370C of the connector unit 370 are exposed externally. It should be noted that, to prevent moisture, dust, and other foreign matter from entering its interior, the cover 380 is preferably sealed to the housing 324 of the motor 320, for example, by using a liquid sealant.

[0039] In the electric power steering system 100, when the driver operates the steering wheel, the input shaft 210 is rotated via the steering shaft. The pinion fixed at the front end of the input shaft 210 rotates, causing the rack to slide to the left or right. If the rack slides to the left or right, its sliding force is transmitted to the steering arm of the steering knuckle via the tie rod 230 and the ball joint 240, and the steering wheel rotates around the axis of the steering pin to steer.

[0040] Furthermore, the electronic control unit 340 determines the steering wheel's operating direction (rotation direction) based on the steering torque detected by the torque sensor 260, and calculates the operating amount of the motor 320 to assist the driver's operating force based on the steering torque and vehicle speed. Then, the electronic control unit 340 supplies a drive current corresponding to the operating amount of the motor 320 to the stator coils, driving the output shaft 322 of the motor 320 to rotate and assist the operating force. At this time, the electronic control unit 340 uses the output signal from the rotation angle sensor attached to the motor 320 to perform feedback control on the motor 320.

[0041] like Figure 8As shown, the ground terminal 370A1 of the power connector 370A of the first system is connected to the ground terminal (not shown) of the first system of the power substrate 350 via a busbar 370A2 that extends backward toward the power substrate 350 through the interior of the connector base 370D of the connector unit 370. Furthermore, the ground terminal of the first system of the power substrate 350 is connected to the ground terminal (not shown) of the first system of the control substrate 360 ​​via a signal transmission path that transmits signals between the power substrate 350 and the control substrate 360. In the illustrated example, this is one of multiple wires 372 (e.g., the leftmost wire 372). Therefore, the ground terminal 370A1 of the power connector 370A of the first system is connected to the ground terminal of the first system of the control substrate 360 ​​via a grounding wire GL1 (shown as a dashed line in the figure) formed by the busbar 370A2, the ground terminal of the first system of the power substrate 350, and the wires 372. In addition, a capacitor 374 of a specified capacity is provided between the bus 370A2 and the ground terminal of the first system of the power supply board 350, which can be exemplified as a noise response component.

[0042] like Figure 8 As shown, the ground terminal 370B1 of the power connector 370B of the second system is connected to the ground terminal (not shown) of the second system of the power board 350 via a busbar 370B2 that extends backward toward the power board 350 through the interior of the connector base 370D of the connector unit 370. Furthermore, the ground terminal of the second system of the power board 350 is connected to the ground terminal (not shown) of the second system of the control board 360 via a signal transmission path that transmits signals between the power board 350 and the control board 360. In the illustrated example, this is one of multiple wires 372 (e.g., the rightmost wire 372). Therefore, the ground terminal 370B1 of the power connector 370B of the second system is connected to the ground terminal of the second system of the control board 360 via a grounding wire GL2 (shown as a dashed line in the figure), which is formed by the busbar 370B2, the ground terminal of the second system of the power board 350, and the wires 372. Furthermore, a capacitor 374 of a specified capacitance, which can be exemplified as a noise mitigation component, is disposed between bus 370B2 and the ground terminal of the second system of power supply board 350. It should be noted that, preferably, the ground terminals of the first system and the second system in power supply board 350 are insulated from each other.

[0043] According to the configuration described above, the grounding wire GL1, which is connected to the grounding terminal 370A1 of the power connector 370A of the first system, is connected to the grounding terminal of the first system of the control board 360 via the grounding terminal of the first system of the power board 350. Furthermore, due to the capacitor 374 disposed at the connection point of the grounding wire GL1 of the first system relative to the power board 350, noise is reduced, and the noise superimposed on the current flowing in the wire 372 connecting the grounding terminals of the first system of the power board 350 and the first system of the control board 360 is reduced. Therefore, it is unnecessary to configure a noise mitigation component at the connection point of the grounding wire GL1 of the first system relative to the control board 360. Compared with the prior art, the wiring of the grounding wire GL1 can be simplified, and the number of noise mitigation components can be reduced. In addition, since the number of noise mitigation components can be reduced, the cost of the electronic control device 340 can be reduced and miniaturized, and the mounting space of the electronic components in the board can be effectively utilized. It should be noted that the functions and effects in the second system are the same as those in the first system, and therefore their description is omitted.

[0044] like Figure 9 As shown, the power terminal 370A3 of the power connector 370A of the first system is connected to the smoothing circuit 350A of the first system on the power board 350 via a busbar 370A4 that extends backward toward the power board 350 through the interior of the connector base 370D of the connector unit 370. Furthermore, the power supply voltage smoothed by the smoothing circuit 350A of the first system on the power board 350 is supplied to the first system of the control board 360 via a power line PL1 composed of one of the multiple wires 372 (e.g., the second wire 372 on the left). Therefore, the power supply voltage supplied to the power terminal 370A3 of the power connector 370A of the first system is smoothed by supplying it to the smoothing circuit 350A of the first system on the power board 350 via the busbar 370A4, and then supplied to the first system of the control board 360 via the power line PL1. In summary, the power terminal 370A3 of the power connector 370A of the first system is connected only to the first system power board 350, which is directly connected to the ground terminal 370A1 of the first system via the bus 370A2.

[0045] like Figure 9As shown, the power terminal 370B3 of the power connector 370B of the second system is connected to the smoothing circuit 350C of the second system on the power board 350 (refer to the dashed line on the right) via a busbar 370B4 extending backward from the connector base 370D of the connector unit 370 and bending through it. Furthermore, the power supply voltage smoothed by the smoothing circuit 350C of the second system on the power board 350 is supplied to the second system on the control board 360 via a power line PL2 composed of one of the multiple wires 372 (e.g., the second wire 372 from the right). Therefore, the power supply voltage supplied to the power terminal 370B3 of the power connector 370B of the second system is smoothed by supplying it to the smoothing circuit 350C of the second system on the power board 350 via the busbar 370B4 and then supplied to the second system on the control board 360 via the power line PL2. In summary, the power terminal 370B3 of the power connector 370B of the second system is connected only to the second system of the power board 350, which is directly connected to the ground terminal 370B1 of the second system via the bus 370B2.

[0046] Here, as Figure 10 As shown, among the multiple wires 372 that transmit signals between the power supply board 350 and the control board 360, the ground wire GL1 and power line PL1 of the first system can be arranged close together, and the ground wire GL2 and power line PL2 of the second system can be arranged close together. In this way, since the current flowing in the ground wire GL1 of the first system is in the opposite direction to the current flowing in the power line PL1 of the first system, the noise superimposed on this current cancels out and is reduced, for example, improving the noise immunity of the first system. Similarly, since the current flowing in the ground wire GL2 of the second system is in the opposite direction to the current flowing in the power line PL2 of the second system, the noise superimposed on this current cancels out and is reduced, for example, improving the noise immunity of the second system.

[0047] At this point, the thickness (board thickness) of the power supply board 350 and the control board 360 can be arranged with a smaller distance between the grounding line GL1 and power line PL1 of the first system, and the grounding line GL2 and power line PL2 of the second system. In this way, since the noise with large amplitude and opposite phase interferes with each other and cancels out, the noise becomes smaller, and the noise immunity performance can be further improved.

[0048] However, the control board 360 requires the use of the power supply circuit 360B of the first system and the power supply circuit 360E of the second system to generate a step-down voltage that reduces the power supply voltage to a specified voltage and supplies it to the power supply board 350. In this case, as... Figure 11As shown, among the multiple conductors 372, it is preferable to arrange the power supply line PL1, ground line GL1, and buck line DL1, which supplies a step-down voltage from the control board 360 to the power supply board 350, in close proximity. This way, since the current flowing from the power supply board 350 to the control board 360 in the power supply line PL1 flows in the opposite direction to the current flowing from the control board 360 to the power supply board 350 in the buck line DL1 and the ground line GL1, the noise superimposed by these currents cancels each other out and is reduced. Furthermore, if the power supply line PL1, ground line GL1, and buck line DL1 are arranged at a distance smaller than the thickness of the power supply board 350 and the control board 360, noise can be effectively reduced. It should be noted that the same applies to the second system.

[0049] Furthermore, the control board 360 needs to use the inverter drive signal generation circuit 360C of the first system and the inverter drive signal generation circuit 360F of the second system to generate drive signals with the same voltage as the power supply voltage of the inverter circuits 350B and 350D of the first system used to drive the power supply board 350, and supply these signals to the power supply board 350. In this case, as... Figure 12 As shown, among the multiple conductors 372, the power supply line PL1, ground line GL1, and signal line SL1 supplying drive signals from the control board 360 to the power supply board 350 of the first system are preferably arranged close together. This way, since the current flowing from the power supply board 350 to the control board 360 in the power supply line PL1 flows in opposite directions to the current flowing from the control board 360 to the power supply board 350 in the signal line SL1 and the ground line GL1, and their voltages are equal, the noise superimposed by the currents cancels each other out and is reduced. Furthermore, if the power supply line PL1, ground line GL1, and signal line SL1 are arranged at a distance smaller than the thickness of the power supply board 350 and the control board 360, noise can be effectively reduced. It should be noted that the same applies to the second system.

[0050] Figure 13 This diagram illustrates a schematic circuit diagram of the control system of an electronic control device 340 having a common ground terminal 360G, where the ground terminals of the first and second systems of the control board 360 are integrated, based on the various embodiments described above. Here, the stator of the motor 320 in the motor unit 300 includes a first coil 320A driven and controlled by the inverter circuit 350B of the first system and a second coil 320B driven and controlled by the inverter circuit 350D of the second system. It should be noted that, as detailed below, the control system of the motor 320 is divided into a first system and a second system.

[0051] [First System]

[0052] As an example of a DC power supply, the ground terminal and power terminal of battery BAT1 are connected to the ground terminal 370A1 and power terminal 370A3 of power connector 370A, respectively. The ground terminal 370A1 of power connector 370A is connected to the ground terminal of inverter circuit 350B mounted on power board 350, and also to the common ground terminal 360G of control board 360. Furthermore, the power terminal 370A3 of power connector 370A is connected to the power terminal of inverter circuit 350B mounted on power board 350, and also to the power terminal of power circuit 360B mounted on control board 360. Moreover, inverter circuit 350B mounted on power board 350 outputs drive current to the first coil 320A of motor 320. It should be noted that power circuit 360B of control board 360 supplies a specified voltage of DC power to microcomputer 360A and inverter drive signal generation circuit 360C.

[0053] The grounding terminals of the microcomputer 360A, power supply circuit 360B, and inverter drive signal generation circuit 360C, all mounted on the control board 360, are connected to a common ground terminal 360G. The microcomputer 360A, mounted on the control board 360, outputs control signals to the inverter drive signal generation circuit 360C and is connected to the microcomputer 360D of the second system. Therefore, the microcomputer 360A of the first system is configured to be able to exchange arbitrary signals with the microcomputer 360D of the second system (and vice versa). The inverter drive signal generation circuit 360C, mounted on the control board 360, outputs drive signals to the inverter circuit 350B mounted on the power supply board 350 based on the control signals from the microcomputer 360A.

[0054] [Second System]

[0055] As an example of a DC power supply, the ground terminal and power terminal of battery BAT2 are connected to the ground terminal 370B1 and power terminal 370B3 of power connector 370B, respectively. The ground terminal 370B1 of power connector 370B is connected to the ground terminal of inverter circuit 350D mounted on power board 350, and also to the common ground terminal 360G of control board 360. Furthermore, the power terminal 370B3 of power connector 370B is connected to the power terminal of inverter circuit 350D mounted on power board 350, and also to the power terminal of power circuit 360E mounted on control board 360. Moreover, inverter circuit 350D mounted on power board 350 outputs drive current to the second coil 320B of motor 320. It should be noted that power circuit 360E of control board 360 supplies a specified voltage of DC power to microcomputer 360D and inverter drive signal generation circuit 360F.

[0056] The grounding terminals of the microcomputer 360D, power supply circuit 360E, and inverter drive signal generation circuit 360F, all mounted on the control board 360, are connected to the common ground terminal 360G. The microcomputer 360D, mounted on the control board 360, outputs control signals to the inverter drive signal generation circuit 360F. Based on the control signals from the microcomputer 360D, the inverter drive signal generation circuit 360F, mounted on the control board 360, outputs drive signals to the inverter circuit 350D mounted on the power supply board 350.

[0057] Here, if either the ground terminal of the power connector 370A of the first system or the power connector 370B of the second system is disconnected, which current flows... Figure 13 The circuit shown is studied by examining the flow in the ground wire. For example, as... Figure 14 As shown, if the ground terminal 370B1 of the power connector 370B in the second system is disconnected, the ground terminal current from the inverter circuit 350D of the power supply board 350 in the second system will not be able to return to the battery BAT2. In this case, the ground terminal current from the inverter circuit 350D of the power supply board 350, as shown by the dashed line A in the figure, flows into the ground wire of the first system via the circuit connecting the ground terminal of the power supply board 350 to the common ground terminal 360G of the control board 360 and the common ground terminal 360G.

[0058] In the grounding wire of the first system, grounding current from the inverter circuit 350B of the power supply board 350 (shown by dashed line B in the figure) and grounding current from the microcomputer 360A, power supply circuit 360B, and inverter drive signal generation circuit 360C of the control board 360 (shown by dashed line C in the figure) typically flow. Furthermore, if the grounding terminal 370B1 of the power connector 370B of the second system breaks, the grounding current of the second system flows further into the grounding wire of the first system. This results in the aforementioned grounding currents A, B, and C flowing through the grounding terminal 370A1 of the power connector 370A of the first system, exceeding, for example, the specified power capacity. Therefore, even a normally functioning power connector 370A may malfunction, posing a risk of sudden loss of power steering in the electric power steering system 100, for example. It should be noted that when the grounding terminal 370A1 of the power connector 370A of the first system breaks, a large current also flows through the grounding wire of the second system.

[0059] For this reason, it is necessary to detect whether a break in the grounding terminal of the power connector 370A in the first system and the power connector 370B in the second system has occurred. By stopping the operation of the inverter circuit of the system with the break in the grounding terminal, it is possible to prevent the normal power connector from also malfunctioning.

[0060] Therefore, as Figure 13 and Figure 14 As shown, for both the first and second systems, current sensing elements 400 and 420, such as shunt resistors, are provided in the circuit (midway of the grounding wire) connecting the grounding terminal of the power supply board 350 and the common grounding terminal 360G of the control board 360. Furthermore, the microcomputer 360A of the first system and the microcomputer 360D of the second system constantly monitor the output from the current sensing elements 400 and 420, and stop the operation of the inverter circuit when the output exceeds a specified value. At this time, the microcomputer of the faulty system notifies the microcomputer of the normal system of the fault occurrence, and if necessary, delegates control of the motor 320. This improves the robustness of the function for detecting grounding disconnections. It should be noted that even if one system fails, control continues through the motor 320 of the normal system, thus not affecting the function of the power steering system 100.

[0061] In the above embodiment, the motor 320 and electronic control device 340 in the motor unit 300 are redundant, but the present invention is also applicable to motors and electronic control devices that do not employ a redundant structure. In this case, the motor 320 has only one coil and the power supply board 350 and control board 360 of the electronic control device 340 also have only one system control system.

[0062] Figure 15 This illustrates another embodiment of the electronic control device 340. It should be noted that, in this other embodiment, to avoid confusion with the previous embodiment, configurations that differ from the previous embodiment are described using ' (quote marks).

[0063] A power connector 370A' and a control connector (not shown) are formed in the connector base 370D' of the connector unit 370'. The ground terminal 370A1' of the power connector 370A' is connected to the ground terminal (not shown) of the power board 350' via a busbar 370A2' that extends backward toward the power board 350' through the interior of the connector base 370D' of the connector unit 370'. Furthermore, the ground terminal of the power board 350' is connected to the ground terminal (not shown) of the control board 360' via a signal transmission path that transmits signals between the power board 350' and the control board 360', which in the illustrated example is one of multiple wires 372' (e.g., the leftmost wire 372'). Therefore, the grounding terminal 370A1' of the power connector 370A' is connected to the grounding terminal of the control board 360' via the grounding line GL' shown by the dashed line on the left side of the figure, which is formed by the bus 370A2', the grounding terminal of the power board 350', and the wire 372'. Furthermore, a capacitor 374' of a specified capacitance, which can be exemplified as a noise mitigation component, is provided between the bus 370A2' and the grounding terminal of the power board 350'.

[0064] The power terminal 370A3' of the power connector 370A' extends from the inside of the connector base 370D' through the connector unit 370' towards the power board 350' via a busbar 370A4', and is connected to the smoothing circuit of the power board 350' (refer to the dashed line on the right side of the figure). Furthermore, the power supply voltage smoothed by the smoothing circuit of the power board 350' is supplied to the control board 360' via a power line PL' composed of one of the multiple wires 372' (e.g., the second wire 272' from the left). Therefore, the power supply voltage supplied to the power terminal 370A3' of the power connector 370A' is smoothed by supplying it to the smoothing circuit of the power board 350' via the busbar 370A4', and then supplied to the control board 360' via the power line PL'. In summary, the power terminal 370A3' of the power connector 370A' is only connected relative to the power board 350', which has a ground terminal 370A1' directly connected via the busbar 370A2'.

[0065] With the above configuration, the grounding wire GL', connected to the grounding terminal 370A1' of the power connector 370A', is connected to the grounding terminal of the control board 360' via the grounding terminal of the power board 350'. Furthermore, because of the capacitor 374' disposed at the connection point of the grounding wire GL' relative to the power board 350', noise is reduced, thus reducing the noise superimposed on the current flowing in the wire 372' connecting the grounding terminal of the power board 350' and the grounding terminal of the control board 360'. Therefore, it is unnecessary to provide noise mitigation components at the connection point of the grounding wire GL' relative to the control board 360', making the wiring of the grounding wire GL' easier and reducing the number of noise mitigation components compared to the prior art. In addition, since the number of noise mitigation components can be reduced, the cost of the electronic control device 340 can be reduced and miniaturized, and the mounting space of the electronic components in the board can be effectively utilized.

[0066] It should be noted that, for the electronic control device 340 which does not employ redundancy, other embodiments of the electronic control device 340 which employs redundancy can also be applied.

[0067] It should be noted that, as will be readily understood by those skilled in the art, new implementation methods can be generated by omitting a part of the technical solutions described above, appropriately combining a part of the technical solutions, or replacing a part of the technical solutions with known technologies.

[0068] As an example, the electronic control device 340 of this embodiment is not limited to the electric power steering system 100; for example, it can also be applied to known systems such as engine control systems, automatic transmission control systems, and autonomous driving systems. In this case, the power supply board 350 is equipped with at least smoothing circuits 350A and 350C, and the control board 360 is equipped with at least microcomputers 360A and 360D.

[0069] Furthermore, the electronic control device 340 is not limited to the power supply board 350 and the control board 360, and may also have three or more boards matching the controlled system. Additionally, in Figure 13 and Figure 14 In the control system of the power steering system 100 shown, a battery shared by the first system and the second system can be used.

[0070] Explanation of reference numerals in the attached figures

[0071] 340… Electronic control device; 350, 350'… Power supply board; 350A, 350C… Smoothing circuit; 360, 360'… Control board; 360A, 360D… Microcomputer; 360G… Common ground terminal; 370A, 370A', 370B… Power connector; 370A1, 370A1', 370B1… Grounding terminal; 370A3, 370A3', 370B3… Power terminal; 400, 420… Current sensing element; DL1, DL2… Step-down line; GL1, GL2, GL'… Grounding wire; PL1, PL2, PL'… Power line; SL1, SL2… Signal line.

Claims

1. An electronic control device, comprising multiple substrates for transmitting signals to each other and a power connector for a DC power supply, characterized in that, The grounding wire connected to the grounding terminal of the power connector is connected to the grounding terminals of the other substrates via one grounding terminal of the plurality of substrates.

2. The electronic control device according to claim 1, The plurality of substrates include: A control board, which has at least one microcomputer mounted on it; A power supply board, which has at least a power supply voltage smoothing circuit installed on it. The grounding wire is connected to the grounding terminal of the control board via the grounding terminal of the power supply board.

3. The electronic control device according to claim 1, The plurality of substrates include: A control board, which has at least one microcomputer mounted on it; A power supply board, which has at least a power supply voltage smoothing circuit installed on it. The grounding wire is connected to the grounding terminal of the power supply board via the grounding terminal of the control board.

4. The electronic control device according to claim 2, The power connector, the microcomputer, and the smoothing circuit have a redundant dual-system configuration. The grounding terminal of the control board is a common grounding terminal shared by all systems. In each system, the grounding wire connecting the grounding terminal of the power supply board to the common grounding terminal of the control board is equipped with a current sensing element for detecting the current flowing in the grounding wire.

5. The electronic control device according to claim 1, The power terminal of the power connector is connected only relative to the base plate to which the ground terminal of the power connector is directly connected.

6. The electronic control device according to claim 5, Among the plurality of substrates, a power line supplying power voltage from one side of the substrate to the other side of the substrate is positioned close to the ground line.

7. The electronic control device according to claim 6, A power line that supplies power voltage from one side of the substrate to the other side of the substrate, a step-down line that steps down the power voltage on the other side of the substrate and supplies it to one side of the substrate, and a ground line are arranged close together among the plurality of substrates.

8. The electronic control device according to claim 6, A power line supplying a power supply voltage from one side of the substrate to the other side of the substrate, a signal line having a voltage of the same magnitude as the power supply voltage supplied from the other side of the substrate to one side of the substrate, and a ground line are arranged close together among the plurality of substrates.

9. The electronic control device according to claim 6, The power line and the ground line are arranged at a distance smaller than the thickness of the substrate.

10. A grounding wire wiring method for an electronic control device comprising multiple substrates for mutual signal transmission and a power connector for a DC power supply, characterized in that, The grounding wire connected to the grounding wire of the power connector is connected to the grounding terminals of the other substrates via one grounding terminal of the plurality of substrates.

11. The grounding wire wiring method according to claim 10, The plurality of substrates include: A control board, which has at least one microcomputer mounted on it; A power supply board, which has at least a power supply voltage smoothing circuit installed on it. The grounding wire is connected to the grounding terminal of the control board via the grounding terminal of the power supply board.

12. The grounding wire wiring method according to claim 10, The plurality of substrates include: A control board, which has at least one microcomputer mounted on it; A power supply board, which has at least a power supply voltage smoothing circuit installed on it. The grounding wire is connected to the grounding terminal of the power supply board via the grounding terminal of the control board.

13. The grounding wire wiring method according to claim 11, The power connector, the microcomputer, and the smoothing circuit have a redundant dual-system configuration. The grounding terminal of the control board is a common grounding terminal shared by all systems. In each system, the grounding wire connecting the grounding terminal of the power supply board to the common grounding terminal of the control board is equipped with a current sensing element for detecting the current flowing in the grounding wire.

14. The grounding wire wiring method according to claim 10, The power terminals of the power connector are connected only relative to the substrate to which the ground terminal of the power connector is directly connected.

15. The grounding wire wiring method according to claim 14, Between the plurality of substrates, a power line that supplies power voltage from one side of the substrate to the other side of the substrate and a ground line are arranged close together.

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