阅读说明：本技术 电路基板 (Circuit board ) 是由 原田一树 山本直树 于 2018-09-28 设计创作，主要内容包括：提供电路基板。电路基板具备：基板主体；电路部,其形成于基板主体,向马达供给电力；正极侧电源端子部,其形成于基板主体,与电路部的正极端子连接；以及负极侧电源端子部,其形成于基板主体,与电路部的负极端子连接。电路部具备与正极侧电源端子部连接的第1电容器和与负极侧电源端子部连接的第2电容器,第1电容器和第2电容器串联连接于正极侧电源端子部与负极侧电源端子部之间。在基板主体上形成有沿厚度方向贯通基板主体的贯通孔,贯通孔的至少一部分形成在被第1电容器、第2电容器、正极侧电源端子部以及负极侧电源端子部中的至少两个夹着的位置。(A circuit substrate is provided. The circuit board includes: a substrate main body; a circuit unit formed on the substrate main body and supplying power to the motor; a positive power supply terminal portion formed on the substrate body and connected to a positive terminal of the circuit portion; and a negative-side power supply terminal portion formed on the substrate body and connected to a negative terminal of the circuit portion. The circuit unit includes a 1 st capacitor connected to the positive-side power supply terminal unit and a 2 nd capacitor connected to the negative-side power supply terminal unit, and the 1 st capacitor and the 2 nd capacitor are connected in series between the positive-side power supply terminal unit and the negative-side power supply terminal unit. The substrate body is formed with a through hole penetrating the substrate body in a thickness direction, and at least a part of the through hole is formed at a position sandwiched by at least two of the 1 st capacitor, the 2 nd capacitor, the positive-side power supply terminal portion, and the negative-side power supply terminal portion.)

1. A circuit board includes:

a substrate main body;

a circuit unit formed on the substrate main body and configured to supply electric power to a motor;

a positive power supply terminal portion of the circuit portion, which is formed on the substrate main body and connected to a positive terminal; and

a negative power supply terminal portion of the circuit portion, which is formed on the substrate main body and connected to the negative terminal,

the circuit part comprises a 1 st capacitor connected to the positive side power supply terminal part and a 2 nd capacitor connected to the negative side power supply terminal part, the 1 st capacitor and the 2 nd capacitor are connected in series between the positive side power supply terminal part and the negative side power supply terminal part,

a through hole penetrating the substrate main body in a thickness direction is formed in the substrate main body,

the positive side power supply terminal portion and the negative side power supply terminal portion are respectively provided with a driving power supply mounting hole,

at least a part of the through-hole is formed in a region surrounded by an outer end portion of the driving power supply mounting hole of each of the positive-side power supply terminal portion and the negative-side power supply terminal portion and outer end portions of the 1 st capacitor and the 2 nd capacitor,

the circuit board further includes a conductor portion formed in at least a part of the through hole,

the conductor portion is electrically connected to the positive-side power supply terminal portion via the 1 st capacitor and is electrically connected to the negative-side power supply terminal portion via the 2 nd capacitor, and at least a part of the conductor portion is a conductor and is electrically connectable to a board mounting unit on which the board main body is mounted.

2. The circuit substrate according to claim 1,

the circuit section has a power supply circuit section,

the power supply unit is electrically connected to the positive-side power supply terminal portion by inserting the positive-electrode terminal into the driving power supply mounting hole of the positive-side power supply terminal portion from a surface opposite to the mounting surface of the power supply circuit portion,

the negative terminal is inserted into the driving power supply mounting hole of the negative power supply terminal portion from a surface opposite to the mounting surface of the power supply circuit portion, whereby the power supply unit is electrically connected to the negative power supply terminal portion.

3. The circuit substrate according to claim 1,

the substrate mounting unit has a plurality of holes,

the circuit board has another through-hole separated from the through-hole,

the circuit board is screwed to the board mounting unit through the plurality of holes, the through hole, and another through hole separate from the through hole of the board mounting unit.

Technical Field

One embodiment of the present invention relates to a circuit board.

Background

A vehicle such as an automobile includes an electric power steering system as an in-vehicle device. When a driver's steering wheel operation is received, the electric power steering system generates an assist torque for assisting a steering torque of the steering system. The electric power steering system can reduce the burden of the driving operation of the driver by generating the assist torque. An assist torque mechanism for generating assist torque detects steering torque, generates a drive signal based on a detection signal, and generates assist torque based on the drive signal by a motor. Whereby an assist torque corresponding to the steering torque is transmitted to the steering system via the speed reducing mechanism.

In the above-described technology, for example, japanese patent No. 5777797 discloses an electric power steering system including a motor drive device. The electric power steering system includes a common mode filter of the motor drive device. The common mode filter includes a common mode coil and a capacitor. However, the common mode coil enlarges the common mode filter. On the other hand, a common mode filter without a common mode coil cannot sufficiently reduce common mode noise, although it can reduce the size of the motor drive device.

Disclosure of Invention

An object of the present invention is to provide a circuit substrate that can contribute to noise reduction.

In an exemplary embodiment of the present application, a circuit board includes: a substrate main body; a circuit unit formed on the substrate main body and configured to supply electric power to a motor; a positive power supply terminal portion of the circuit portion, which is formed on the substrate main body and connected to a positive terminal; and a negative-side power supply terminal portion of the circuit portion, which is formed on the substrate main body and connected to a negative terminal, wherein the circuit portion includes a 1 st capacitor connected to the positive-side power supply terminal portion and a 2 nd capacitor connected to the negative-side power supply terminal portion, the 1 st capacitor and the 2 nd capacitor are connected in series between the positive-side power supply terminal portion and the negative-side power supply terminal portion, a through hole penetrating the substrate main body in a thickness direction is formed in the substrate main body, the positive-side power supply terminal portion and the negative-side power supply terminal portion each have a driving power supply mounting hole, and at least a part of the through hole is formed in a region surrounded by an outer end portion of the driving power supply mounting hole of each of the positive-side power supply terminal portion and the negative-side power supply terminal portion and an outer end portion of the 1 st capacitor and the 2 nd capacitor, the circuit board further includes a conductor portion formed in at least a part of the through hole, the conductor portion being electrically connected to the positive-side power supply terminal portion via the 1 st capacitor and electrically connected to the negative-side power supply terminal portion via the 2 nd capacitor, at least a part of the conductor portion being a conductor and being electrically connectable to a board mounting unit on which the board main body is mounted.

The circuit unit includes a power supply circuit unit, and the power supply unit is electrically connected to the positive-side power supply terminal portion by inserting the positive terminal into the driving power supply mounting hole of the positive-side power supply terminal portion from a surface opposite to a mounting surface of the power supply circuit unit, and the power supply unit is electrically connected to the negative-side power supply terminal portion by inserting the negative terminal into the driving power supply mounting hole of the negative-side power supply terminal portion from a surface opposite to the mounting surface of the power supply circuit unit.

The board mounting unit has a plurality of holes, the circuit board has another through hole separated from the through hole, and the circuit board is screwed to the board mounting unit through the plurality of holes, the through hole, and the other through hole separated from the through hole of the board mounting unit.

According to an exemplary embodiment of the present application, noise reduction can be facilitated.

The foregoing and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments with reference to the attached drawings.

Drawings

Fig. 1 is a schematic diagram showing a configuration example of an electric power steering system according to an embodiment.

Fig. 2 is a circuit diagram showing an example of the internal configuration of the electronic control unit.

Fig. 3 is an exploded perspective view of the electronic control unit.

Fig. 4A is a plan view of the cover unit.

Fig. 4B is a plan view of the circuit substrate.

Fig. 4C is a plan view of the substrate mounting unit.

Fig. 5 is a plan view showing an example of a conductor pattern in the circuit board.

Fig. 6 is a cross-sectional view showing an example of an in-layer structure in the circuit board.

Fig. 7 is a cross-sectional view showing another example of the layer structure in the circuit board 200.

Fig. 8 is a plan view of another circuit substrate.

Fig. 9 is a plan view of another circuit substrate.

Fig. 10 is a schematic diagram showing an example of the positional relationship among the through-hole, the first capacitor, the second capacitor, the driving power supply mounting hole, and the driving power supply mounting hole.

Fig. 11 is a diagram for explaining a region where a through hole can be formed.

Fig. 12 is a diagram for explaining another region where a through hole can be formed.

Fig. 13 is a perspective view showing an example of a substrate mounting unit according to a modification.

Detailed Description

Hereinafter, a circuit board and a control device to which the present invention is applied will be described with reference to the drawings.

Fig. 1 is a schematic diagram showing a configuration example of an electric power steering system 1 according to an embodiment. The electric power steering system 1 includes, for example, a steering system 10, an auxiliary torque mechanism unit 30, a control device 50, and a battery 51. The electric power steering system 1 transmits the assist torque generated by the assist torque mechanism section 30 to the steering system 10. The electric power steering system 1 functions as a motor drive device that drives a motor described later to generate assist torque.

The steering system 10 is provided with a steering wheel 11, a steering shaft 12, universal joints 13A and 13B, a rotating shaft portion 14, a rack and pinion 15, a rack shaft portion 16, tie rods 17A and 17B, knuckles 18A and 18B, steered wheels 19A and 19B, and ball joints 20A and 20B.

The steering wheel 11 is operated by the driver of the vehicle. The steering shaft 12, the universal joints 13A and 13B, and the rotating shaft portion 14 (also referred to as a pinion shaft, an input shaft) are coupled to the steering wheel 11 in this order. The rack shaft portion 16 is coupled to the rotation shaft portion 14 via a rack and pinion 15. Left and right steered wheels 19A and 19B are coupled with both ends of the rack shaft portion 16 via left and right ball joints 20A and 20B, left and right tie rods 17A and 17B, and left and right knuckles 18A and 18B. The rack-and-pinion 15 includes a pinion 15a and a rack 15 b. The pinion gear 15a is coupled to the rotation shaft 14. The rack 15b is provided in the rack shaft portion 16.

According to the steering system 10, when the driver manipulates the steering wheel 11, the steered wheels 19A and 19B can be steered by the steering torque via the rack and pinion 15.

The assist torque mechanism 30 includes, for example, a steering torque detection unit 31, an electronic control unit 32, a motor 33, and a speed reduction mechanism 34.

The steering torque detection unit 31 is, for example, a steering torque sensor. The steering torque detection unit 31 detects the steering torque applied to the steering wheel 11 and generates a torque signal.

The motor 33 is, for example, a motor having three-phase motor power supply terminals including U-phase, V-phase, and W-phase. The motor 33 is, for example, a brushless motor. The motor 33 generates an assist torque according to the drive signal. The assist torque is transmitted to the rotation shaft 14 via the speed reduction mechanism 34.

The speed reduction mechanism 34 is, for example, a worm gear mechanism. The assist torque transmitted to the rotation shaft portion 14 is transmitted from the rotation shaft portion 14 to the rack and pinion pair 15.

The electronic control unit 32 includes, for example, a power supply circuit, a current sensor for detecting a motor current (actual current), a microprocessor, a Field Effect Transistor (FET) bridge circuit, and a magnetic sensor 32 a. The magnetic sensor 32a detects the rotation angle of the rotor in the motor 33. The rotor is, for example, a permanent magnet, and the magnetic sensor 32a detects the rotation angle by detecting the movement of the permanent magnet (N pole and S pole).

The electronic control unit 32 inputs not only the torque signal but also, for example, a vehicle speed signal as an external signal. The electronic control unit 32 calculates an assist torque to be generated by the motor 33 with respect to the steering torque indicated by the torque signal. The electronic control unit 32 generates a drive signal so that the calculated assist torque is generated at the motor 33.

The control device 50 is an electronic control unit that CAN communicate with another electronic control unit via an in-vehicle Network such as a CAN (Controller Area Network). The control device 50 may be, for example, a vehicle speed sensor capable of outputting a vehicle speed pulse corresponding to a vehicle speed signal. The external signal includes a signal of the electric power steering system 1 such as a torque signal and a signal of the vehicle (vehicle body signal) such as a vehicle speed signal. The vehicle body signal may include not only a vehicle speed signal, an engine speed, and other communication signals, but also a signal indicating on or off of an ignition switch.

The microprocessor of the electronic control unit 32 performs vector control of the motor 33 by operating the FET bridge circuit in accordance with, for example, a torque signal and a vehicle speed signal. The FET bridge circuit is, for example, an inverter circuit INV (see fig. 2) for supplying a drive current (three-phase alternating current) to the motor 33. As shown in fig. 2, for example, the FET bridge circuit includes a FET1, a FET2, a FET3, a FET4, a FET5, and a FET 6.

The electronic control unit 32 sets the target current based on a torque signal representing at least the steering torque. Preferably, the electronic control unit 32 also sets the target current in consideration of the vehicle speed of the vehicle and the rotation angle of the rotor. The electronic control unit 32 controls the drive current (drive signal) of the motor 33 so that the motor current (actual current) coincides with the target current.

The battery 51 is a storage battery that stores electric power supplied to the electronic control unit 32. B + represents a positive potential of the battery 51 provided in the vehicle as a dc power supply, for example, and B-represents a negative potential of the battery 51. The negative pole potential B-is grounded with the body of the vehicle. In addition, the electronic control unit 32 is provided with terminals (a positive terminal T + and a negative terminal T-) as portions connected or in contact with the terminals on the battery 51 side at a power supply connector PCN as an external connector. The power supply voltage, which is the difference between the positive electrode potential B + and the negative electrode potential B-, is the source of the drive voltage of the motor 33.

Fig. 2 is a circuit diagram showing an example of the internal configuration of the electronic control unit 32. The electronic control unit 32 generates an assist torque based on the steering torque by the motor 33, but the use of the electronic control unit 32 of fig. 2 is not limited thereto. That is, the electronic control unit 32 in fig. 2 may be configured to drive the three-phase ac motor, and the microprocessor in fig. 2 may be configured to control the drive current of the three-phase ac motor based on an arbitrary signal.

The electronic control unit 32 is formed on the circuit substrate BD. A substrate positive connection portion CN + and a substrate negative connection portion CN-, inverter output terminals TU, TV, and TW are formed on the circuit substrate BD. The substrate positive connection CN + and the substrate negative connection CN-are connected to the battery 51. The inverter output terminals TU, TV, and TW are connected to the motor 33. The power circuit part PC is connected between the substrate positive connection part CN + and the substrate negative connection part CN-and the inverter output terminals TU, TV and TW.

The substrate positive connection portion CN + is connected to the positive terminal T +. The positive terminal T + corresponds to an input terminal to which the positive potential B + of the battery 51 is input. The positive terminal T + is applied with the positive potential B + of the battery 51. The potential B + is transmitted to the substrate positive connection portion CN +.

The substrate negative connection CN-is connected to the negative terminal T-. The negative terminal T-corresponds to the input terminal to which the negative potential B of the battery 51 is input. The substrate negative connection CN-is connected to the negative terminal T-. The negative terminal T-is applied with the negative potential B-of the battery 51. The potential B-is transferred to the substrate negative connection CN-. When the negative terminal T-is grounded to the body of the vehicle, the potential B-is the same potential as the GND potential of the body.

The inverter circuit INV includes 6 FETs 1 to 6. The 6 FETs 1 to 6 are connected between the positive line of potential B + connected to the positive substrate connector CN + and the negative line of potential B-connected to the negative substrate connector CN-. The field effect capacitor C10 is connected in parallel to the inverter circuit INV between the positive electrode line and the negative electrode line. The electrolytic capacitor C10 smoothes the power supply voltage (the difference between the potential B + and the potential B-).

The FETs 1 and 2 are connected in series between the positive and negative lines. The FET1 and FET2 provide U-phase current to the U-phase winding of the motor 33. A shunt resistor R1 is connected in series with FET1 and FET2 between FET2 and the negative rail. The current flowing through the shunt resistor R1 is detected by a current sensor (not shown) for detecting the U-phase current. The FET7 is connected between a line connecting the FETs 1 and 2 and the inverter output terminal TU. The FET7 cuts or passes the U-phase current.

The FETs 3 and 4 are connected in series between the positive and negative lines. The FETs 3 and 4 provide the V-phase current to the V-phase winding of the motor 33. A shunt resistor R2 is connected in series with the FET3 and FET4 between the FET4 and the negative line. The current flowing through the shunt resistor R2 is detected by a current sensor (not shown) for detecting the V-phase current. The FET8 is connected between the line connecting the FETs 3 and 4 and the inverter output terminal TV. The FET8 cuts or passes the V-phase current.

The FETs 5 and 6 are connected in series between the positive and negative lines. The FETs 5 and 6 supply the W-phase current to the W-phase winding of the motor 33. A shunt resistor R4 is connected in series with the FET5 and FET6 between the FET6 and the negative line. The current flowing through the shunt resistor R3 is detected by a current sensor (not shown) for detecting the W-phase current. The FET9 is connected between the line connecting the FETs 5 and 6 and the inverter output terminal TW. The FET9 cuts off or passes the W-phase current.

The inverter output terminal TU is connected to a motor power supply terminal T1 of the motor 33 via a power supply line portion LNU. The inverter output terminal TV is connected to a motor power supply terminal T2 of the motor 33 via a power supply line portion LNV. The inverter output terminal TW is connected to a motor power supply terminal T3 of the motor 33 via a power supply line portion LNW.

The FETs 1 to 6 are PWM-controlled to supply the U-phase current, the V-phase current, and the W-phase current to the motor 33. For example, FET10 and FET11 are connected as semiconductor relays capable of cutting off power to the front stage of node ND + of the positive line connecting inverter circuit INV and electrolytic capacitor C10. Further, the normal state filter NF is provided in a preceding stage of the FETs 10 and 11. The normal state filter NF includes a coil CL1 and a capacitor C11. Coil CL1 is connected between FET10 and substrate positive connection CN +. The capacitor C11 is connected in parallel with the field capacitor C10 between the positive line and the negative line. The normal mode filter NF can reduce normal mode noise (normal mode noise) superimposed on the positive electrode line.

The front stage of the normal mode filter NF is connected to the common mode filter CF. The common mode filter CF has, for example, a first capacitor C1 and a second capacitor C2 connected in parallel with the electrolytic capacitor C10. The first capacitor C1 and the second capacitor C2 are connected in series between the positive line and the negative line.

The common mode filter CF is connected between the substrate positive connection CN + and the substrate negative connection CN-. Specifically, one end of the first capacitor C1 is connected to the positive substrate connection CN + via a positive electrode line. One end of the second capacitor C2 is connected to the substrate negative connection CN-via a negative line. The other end of the first capacitor C1 is connected to a position P11 of the conductor part CON. The other end of the second capacitor C2 is connected to a position P12 of the conductor part CON.

The conductor part CON is a material through which a current due to common mode noise can flow. The conductor part CON is formed in the through hole H. The through hole H is a hole penetrating the circuit board BD in the thickness direction of the circuit board BD. The conductor part CON is electrically connected to the conductor pattern connected to the other end of the first capacitor C1, and is electrically connected to the conductor pattern connected to the other end of the second capacitor C2. The conductor part CON is electrically connected to a conductive part P4 of the CASE. Thus, in the conductor part CON, a current may flow between the first capacitor C1 and the second capacitor C2, and a current may flow between the first capacitor C1 and the second capacitor C2 and the CASE.

Although the potential of the portion P4 of the CASE is different from the potential B- (GND potential), the portion P4 is preferably grounded to the vehicle body of the vehicle. When the potential of the portion P4 of the CASE is the potential B- (GND potential), the conductor portion CON can further reduce the common mode noise.

The circuit board BD is also provided with a control circuit portion CC. The control circuit unit CC includes a drive circuit that generates 6 control signals (gate signals) corresponding to the FETs 1 to 6 based on the target current, and turns on or off the FETs 1 to 6 by the 6 control signals to supply the drive signals (drive current) to the electric motor 33. The control circuit section CC includes a power supply circuit CC1, a microprocessor CC2, and a drive circuit CC 3. The power supply circuit CC1 generates a power supply voltage (difference between the potential V and the potential GND) of the control circuit part CC by, for example, a connection point of the FET10 and the coil CL1 and a power supply voltage (difference between the potential B + and the potential B- (potential GND)) of the ND-pull-in power supply circuit part PC. Microprocessor CC2 sets a target current for motor 33. The drive circuit CC3 generates control signals for turning on/off the FETs 1 to 6 in the inverter circuit INV, respectively, and supplies them to the FETs 1 to 6.

Microprocessor CC2 controls FETs 7 through 11. The microprocessor CC2 determines on/off states for the FETs 7 to 11, respectively. The driver circuit CC3 generates 5 control signals corresponding to the FETs 7 to 11 based on the determination result, and supplies them to the FETs 7 to 11.

Fig. 3 is an example of an exploded perspective view of the electronic control unit 32. The electronic control unit 32 includes, for example, a cover unit 100, a circuit board 200, and a board mounting unit 300. The electronic control unit 32 is configured such that the circuit board 200 is sandwiched between the cover unit 100 and the board mounting unit 300.

Fig. 4A is a plan view of the cover unit 100. Fig. 4A is a view of the cover unit 100 as viewed from below in fig. 3. The cover unit 100 is, for example, a cover made of metal. The cover unit 100 is formed in a size such that the circuit substrate 200 is not exposed to the outside. Further, the cover unit 100 is formed in a convex shape corresponding to, for example, the circuit component 202 mounted in the circuit substrate 200. Further, as shown in fig. 4A, a position of the cover unit 100 corresponding to a position to be screwed is formed in a convex shape.

Fig. 4B is a plan view of the circuit substrate 200. The circuit board 200 corresponds to the circuit board BD described above. The circuit board 200 is mounted with the circuit components 202 such as the electrolytic capacitor C10 described above. The circuit substrate 200 has through holes 204a, 204b, 204c, and 204d, driving power supply mounting holes 206a and 206b, and a control signal mounting hole 208, for example, formed therein. In addition, a through hole is only described as "through hole 204" when the through hole is not distinguished from other through holes. In addition, the drive power supply mounting hole is described as "drive power supply mounting hole 206" only when the drive power supply mounting hole is not distinguished from other drive power supply mounting holes.

Through holes 204a, 204b, and 204c are formed in the vicinity of the outer end portion of the circuit substrate 200. The through hole 204d is formed at a position inside the outer end of the circuit board 200. The through hole 204d corresponds to the through hole H described above. The positions where the through-holes 204d are formed correspond to the above-described P11 and P12.

The bolt 210a is inserted into the through hole 204 a. The bolt 210b is inserted into the through hole 204 b. The bolt 210c is inserted into the through hole 204 c. The bolt 210d is inserted into the through hole 204 d. The bolts 210a, 210b, 210c, and 210d are inserted into the screw holes 302a, 302b, 302c, and 302d of the substrate mounting unit 300 via the through holes 204a, 204b, 204c, and 204 d. The bolts 210a, 210b, 210c, and 210d screw-fasten the circuit substrate 200 and the substrate mounting unit 300 through a screw-fastening process.

Although the bolts 210a, 210b, and 210c are conductors, they are not limited thereto and may not be conductors. The bolt 210d is a conductor. The bolt 210d corresponds to the conductor part CON described above.

The plus terminal 402 of the power supply unit 400 is inserted into the drive power supply mounting hole 206a from the face opposite to the mounting face of the power supply circuit section PC. The driving power supply mounting hole 206a is electrically connected to the power supply unit 400 by being mechanically connected to the positive terminal 402 of the power supply unit 400. The negative terminal 404 of the power supply unit 400 is inserted into the driving power supply mounting hole 206b from the opposite side to the mounting side of the power supply circuit section PC. The driving power source mounting hole 206b is electrically connected to the power source unit 400 by being mechanically connected to the negative terminal 404 of the power source unit 400.

The signal connection terminals 406 and 408 of the power supply unit 400 are inserted into the control signal mounting hole 208 from the opposite side to the mounting side of the power supply circuit section PC. The control signal mounting hole 208 is electrically connected to the power supply unit 400 by being mechanically connected to the signal connection terminals 406 and 408 of the power supply unit 400.

Fig. 4C is a plan view of the substrate mounting unit 300. The substrate mounting unit 300 is, for example, a heat sink, but is not limited thereto. The substrate mounting unit 300 may be, for example, a bearing holder. The board mounting unit 300 may be a unit in which a heat sink and a bearing holder are integrated. A motor case (not shown) is screwed to the surface of the board mounting unit 300 opposite to the surface on which the circuit board 200 is mounted. The motor case is a case that houses the motor 33.

Screw holes 302a, 302b, 302c, and 302d are formed in the substrate mounting unit 300. Screw holes 302a, 302b, and 302c are formed near the outer end of the substrate mounting unit 300. The screw hole 302d is formed at a position inside the outer end portion of the board mounting unit 300. The position where the screw hole 302d is formed corresponds to the above-described P4.

The bolt 210a inserted into the through hole 204a is inserted into the screw hole 302 a. The bolt 210b inserted into the through hole 204b is inserted into the screw hole 302 b. The bolt 210c inserted into the through hole 204c is inserted into the screw hole 302 c. The bolt 210d inserted into the through hole 204d is inserted into the screw hole 302 d.

At least a part of the substrate mounting unit 300 is formed of a conductor. Specifically, a part of the board mounting unit 300 including the screw hole 302d is formed of a conductor. Preferably, a portion of the board mounting unit 300 including the screw hole 302d is connected to a GND terminal (not shown) and has the same potential as the GND potential.

The power supply unit 400 includes, for example, a positive terminal 402, a negative terminal 404, and signal connection terminals 406 and 408. Further, the power supply unit 400 is formed with a screw hole 410 for screwing the power supply unit 400 to the board mounting unit 300. In the screw fastening step, the power supply unit 400 and the board mounting unit 300 are mechanically connected by inserting the bolts 412 into the screw holes 410. At this time, the positive terminal 402 is mounted in the driving power supply mounting hole 206a, the negative terminal 404 is mounted in the driving power supply mounting hole 206b, and the signal connection terminals 406 and 408 are mounted in the control signal mounting hole 208. Soldering is performed by a solder flowing process in a state where the positive terminal 402 is mounted in the driving power supply mounting hole 206 a. Thereby electrically connecting the positive terminal 402 with the drive power supply mounting hole 206 a. The negative terminal 404 is electrically connected to the driving power supply mounting hole 206b by soldering through a solder flowing process in a state where the negative terminal 404 is mounted in the driving power supply mounting hole 206 b.

Fig. 5 is a plan view showing an example of the conductor pattern in the circuit board 200. Fig. 6 is a cross-sectional view showing an example of an in-layer structure of the circuit board 200, and is a cross-sectional view taken along line a-a # in fig. 5.

For example, as shown in fig. 6, the circuit substrate 200 is formed in a four-layer structure. That is, the circuit board 200 includes, for example, an L1 layer 200A, L2 layer 200B, L3 layer 200C and an L4 layer 200D. From the substrate-mounted unit 300 side, the layers were laminated in the order of L4 layer 200D, L3 layer 200C, L2 layer 200B, L1 layer 200A. The L1 layer 200A is disposed on the cover unit 100 side. The L4 layer 200D is disposed on the board mounting unit 300 side, i.e., on the motor 33 side.

As shown in fig. 5 and 6, a first capacitor C1, conductor patterns 220A and 220b, a through hole 204d, a second capacitor C2, conductor patterns 222a and 222b, and a conductor pattern 224 are formed on the surface of the L1 layer 200A on the cover unit 100 side (hereinafter referred to as the 1 st surface 200A). A protective layer 230a is formed on the conductor pattern 220 a. A protective layer 230b is formed on the conductor pattern 220 b. A protective layer 230C is formed between the first capacitor C1 and the L1 layer 200A. A protective layer 230d is formed on the conductor pattern 222 a. A protective layer 230e is formed on the conductor pattern 222 b. A protective layer 230f is formed between the second capacitor C2 and the L1 layer 200A. The conductor pattern 220a is electrically connected to the positive terminal T +. The first capacitor C1 is electrically connected to the conductor pattern 220 a. The first capacitor C1 is electrically connected to the conductor pattern 220 b. The conductor pattern 224 is formed around the through-hole 204d of the 1 st surface 200 a. The conductor pattern 220b is electrically connected to the conductor pattern 224. As shown in fig. 6, the conductor pattern 224 is electrically connected to the bolt 210d in a state where the bolt 210d is screwed. The conductor pattern 224 is electrically connected to the conductor pattern 222 a. The second capacitor C2 is electrically connected to the conductor pattern 222 a. The second capacitor C2 is electrically connected to the conductor pattern 222 b. The conductor pattern 222b is electrically connected to the negative terminal T-.

In addition, as shown in fig. 5, the conductor pattern 220b and the conductor pattern 222a are directly connected, but not limited thereto, and in the case where the bolt 210d is mounted, the first capacitor C1 and the second capacitor C2 may be electrically connected, and the first capacitor C1 and the second capacitor C2 may be electrically connected to the substrate mounting unit 300. That is, the conductor pattern 220b and the conductor pattern 222a may not be electrically connected to each other, and may be connected to the conductor pattern 224. Further, the conductor pattern 220b and the conductor pattern 222a may not be connected to the conductor pattern 224, respectively, but may be electrically connected to the conductor pattern 224 via the bolt 210d when the bolt 210d is attached.

As shown in fig. 5, conductor patterns 220c and 220d are formed around the driving power supply mounting hole 206 a. The conductor patterns 220c and 220d are connected to the positive terminal 402 via solder using a solder flow process. Conductor patterns 222c and 222d are formed around the driving power supply mounting hole 206 b. The conductor patterns 222c and 222d are connected to the negative terminal 404 via solder by a solder flow process. In fig. 5, the conductor pattern 222b may not have a conductor pattern in a region sandwiched between the conductor pattern 220b and the conductor pattern 220 a. In fig. 5, the protective layer is exposed to the region of the 1 st surface 200a where no conductor pattern is formed.

In the L1 layer 200A, L2 layer 200B, L3 layer 200C and the L4 layer 200D, inlays (not shown) are formed in through holes (not shown) that penetrate the L4 layer 200D in the thickness direction from the L1 layer 200A. The inlay is a material having a good heat transfer efficiency, such as copper, which is embedded in a through hole having a diameter of several millimeters. FETs 1 to 6 are mounted on the surface of the circuit board 200 on the cover unit 100 side. The inlays and the through holes are disposed on the substrate-mounted unit 300 side of the FETs 1 to 6 mounted on the L1 layer 200A. The inlays can transfer heat generated by switching of the FETs 1 to 6 to the board mounting unit 300.

In the circuit board 200 shown in fig. 6, the conductor pattern formed on the L1 layer 200A is connected to the positive terminal T + and the negative terminal T-, but the present invention is not limited thereto. The L2 layer 200B may also be a power layer connected to the positive terminal T + via the substrate positive connection CN +. The L3 layer 200C may also be a GND layer connected to the negative terminal T-via the substrate negative connection CN-.

As described above, in the electronic control unit 32 of the present embodiment, the bolt 210d electrically connects the first capacitor C1 and the second capacitor C2 in a state of being screwed into the screw hole 302d, and is electrically connected to the conductor pattern 224 and the board mounting unit 300. Thus, the circuit board 200 can reduce common mode noise. That is, the circuit board 200 is formed with a conductor portion (bolt 210d) which is electrically connected to the first capacitor C1, the second capacitor C2, the positive substrate connection portion CN +, and the negative substrate connection portion CN-, and at least a part of which is a conductor, and which is electrically connectable to the substrate mounting unit 300 on which the circuit board 200 is mounted. Thus, according to the circuit board 200, a current generated by at least a part of the common mode noise generated during the motor driving can be caused to flow through the board mounting unit 300 via the conductor part CON, and as a result, the common mode noise can be reduced.

Further, according to the circuit substrate 200, the through-hole H (the through-hole 204d) penetrating the substrate main body in the thickness direction is formed, and at least a part of the through-hole is formed at a position sandwiched between at least two of the first capacitor C1, the second capacitor C2, the substrate positive connection portion CN + and the substrate negative connection portion CN-. Thus, according to the circuit board 200, the circuit board 200 can be mounted on the board mounting unit 300 through the through hole. In this case, by using the bolt 210d for positioning between the circuit board 200 and the board mounting unit 300, it is possible to cause a current due to noise generated at the time of driving the motor to flow to GND via the bolt 210 d. As a result, the circuit board 200 can contribute to reduction of common mode noise.

The common mode noise is alternating current (current containing a large amount of AC component) generated due to variation in voltage applied to the coil of the motor 33. The common mode noise is transmitted to the board mounting unit 300 via the parasitic capacitance of the coil of the motor 33, and is transmitted from the board mounting unit 300 to the negative terminal T-of the battery 51 via the GND conductor such as the vehicle body. This causes the potential (GND potential) at the negative terminal T-to fluctuate. Assuming that there is no conductor part CON, the common mode noise is transmitted to the substrate negative connection part CN-via the substrate mounting unit 300, the vehicle body, the negative terminal T-, forming a large loop.

In contrast, by forming the conductor part CON between the first capacitor C1 and the second capacitor C2 as in the present embodiment, even if the common mode noise is transmitted to the substrate mounting unit 300, it is transmitted from the substrate mounting unit 300 to the conductor part CON, the first capacitor C1 and the second capacitor C2, the substrate positive connection part CN + and the substrate negative connection part CN ", thereby forming a ring smaller than that when there is no conductor part CON. Further, since the common mode noise contains a large amount of AC components, the first capacitor C1 and the second capacitor C2 having lower impedance than the vehicle body and the like flow in. Thus, according to the circuit board 200, the loop of the common mode noise can be reduced as compared with the case where the conductor part CON is not provided, and the common mode noise can be reduced.

In addition, for example, when the conductor part CON is formed in the GND part (the substrate negative connection part CN-) of the circuit substrate 200 and mounted on the substrate mounting unit 300, there is a concern that the DC component may affect the circuit substrate 200. The impedance of the GND conductor such as a vehicle body electrically connected to the board mounting unit 300 varies due to mechanical contact or the like at the fastening portion between the conductors. Since the impedance of the GND conductor such as a vehicle body varies, the current flowing through the GND conductor such as a vehicle body also varies. As a result, when the conductor part CON is formed in the GND part of the circuit board 200 and mounted on the board mounting unit 300, the GND level may become unstable and the operation of the motor driving device (power supply circuit part PC) may become unstable. By forming the conductor part CON between the first capacitor C1 and the second capacitor C2 as in the present embodiment, the influence of the DC component on the circuit board 200 can be avoided.

In addition, according to the circuit board 200, when the through hole H is formed as a screw hole, the common mode noise can be reduced without adding a new step only by the step of screwing the circuit board 200 and the board mounting unit 300.

Further, according to the circuit board 200, since the 1 st conductor pattern 224 formed around the through hole 204d is provided, the conductor pattern 224 can be formed in the same step as the conductor pattern (220a or the like) for conducting the first capacitor C1 and the second capacitor C2, and there is no need to add a new step. Further, by enlarging the area of the conductor pattern 224, the effect of noise reduction can be improved. In addition, according to the circuit board 200, by providing the conductor patterns 220g and 222g in the through-hole 204d, the contact area between the bolt 210d and the conductor pattern can be enlarged, and the effect of noise reduction can be further improved.

Fig. 7 is a cross-sectional view showing another example of the layer structure in the circuit substrate 200, and is a cross-sectional view along the line a-a # in fig. 5. Although the through-hole 204d described above has the conductor pattern 224 formed on the 1 st surface 200a, the conductor portion 228 may be provided on the inner wall instead of the conductor pattern 224, or the conductor portion 228 may be provided on the inner wall in addition to the conductor pattern 224. The conductor portion 228 is electrically connected to the conductor pattern 226 formed on the board-mounted unit 300 side surface of the L4 layer 200D. Further, the noise reduction effect can be further improved by increasing the area of the conductor portion 228. According to the circuit board 200, the conductor portion 228 in the through hole 204d is provided, so that the contact area between the bolt 210d and the conductor can be increased, and the effect of noise reduction can be improved. In addition, according to the circuit board 200, the effect of noise reduction can be further improved by enlarging the area of the conductor pattern 224.

Fig. 8 is a top view of another circuit substrate 200. As shown in fig. 8, the conductor pattern may be formed in a different shape from that of fig. 5. In this conductor pattern, the conductor pattern 220a and the conductor pattern 222b are formed in a symmetrical shape with the gap therebetween as the center. Further, a through hole 204d is formed in a region sandwiched between the cutout portion 220a # of the conductor pattern 220a and the cutout portion 222b # of the conductor pattern 222 b.

One end of the first capacitor C1 is provided in the cutout portion 220a # of the conductor pattern 220 a. Further, a conductor pattern 220b is formed on the other end side of the first capacitor C1, and the other end of the first capacitor C1 is connected to the conductor pattern 220 b. The conductor pattern 220b is connected to the conductor pattern 224. The other end of second capacitor C2 is provided in notch portion 222b # of conductor pattern 222 b. Further, a conductor pattern 222a is formed on one end side of the second capacitor C2, and one end of the second capacitor C2 is connected to the conductor pattern 222 a. The conductor pattern 222a is connected to the conductor pattern 224.

Fig. 9 is a plan view of another circuit substrate 200. The conductor pattern 220a has two cutout portions 220a #1 and 220a # 2. The conductor pattern 222b has notches 222b #1 and protrusions 222b # 2. The through-hole 204d, the conductive pattern 220b, and the conductive pattern 222a are formed in a region surrounded by the notches 220a #1, 220a #2, and 222b #1, and the projection 220b # 2.

The circuit board 200 having the conductor pattern shown in fig. 8 or 9 can contribute to reduction of common mode noise, as in the above-described embodiment.

Fig. 10 is a schematic diagram showing an example of the positional relationship among the through-hole 204d, the first capacitor C1, the second capacitor C2, the driving power supply mounting hole 206a (P2), and the driving power supply mounting hole 206b (P3). Assuming that there is a 1 st line L1 passing through a midpoint (1) between a position P2 of the substrate positive connection CN +, i.e., the position of the driving power supply mounting hole 206a, and a position P3 of the substrate negative connection CN-, i.e., the position of the driving power supply mounting hole 206b, and a midpoint (2) between the first capacitor C1 and the second capacitor C2, at least a portion of the through-hole 204d is formed at a position where the 1 st line L1 intersects a 2 nd line L2 connecting the first capacitor C1 and the second capacitor C2.

When the cover unit 100 and the board mounting unit 300 are screwed to the circuit board 200, a current loop including the through hole 204d can be formed. The current loop with the through hole 204d is smaller than the current loop without the through hole 204. As a result, according to the circuit board 200, the current caused by the noise generated during the motor driving can be made to flow to the positive substrate connection portion CN + and the negative substrate connection portion CN ″ via the conductor portion CON, the first capacitor C1, and the second capacitor C2 in the through hole 204d, and thus, it is possible to contribute to the reduction of the common mode noise.

As shown in fig. 10, in the circuit substrate 200, the driving power supply mounting hole 206a may be formed at the 1 st position in the 1 st direction, the driving power supply mounting hole 206b may be formed at the 2 nd position in the 1 st direction, and at least a part of the through hole 204d may be formed at a position between the 1 st position and the 2 nd position in the 1 st direction. The 1 st direction is a direction in which a line connecting a position where the driving power supply mounting hole 206a is formed and a position where the driving power supply mounting hole 206b is formed extends. The 1 st position refers to a position where the driving power supply mounting hole 206a can be formed, and is a position where the positive terminal 402 is connected. The 2 nd position refers to a position where the driving power supply mounting hole 206b can be formed, and is a position where the negative terminal 404 is connected. In this case, the circuit board 200 can form a current loop including the through hole 204 d. The current loop with the through hole 204d is smaller than the current loop without the through hole 204.

As shown in fig. 10, in the circuit substrate 200, it may be that the first capacitor C1 is formed at the 3 rd position in the 2 nd direction, the second capacitor C2 is formed at the 4 th position in the 2 nd direction, and at least a part of the through-hole 204d is formed at a position between the 3 rd position and the 4 th position in the 2 nd direction. The 2 nd direction is a direction in which a line connecting a position where the first capacitor C1 is formed and a position where the second capacitor C2 is formed extends. The 3 rd position refers to a position where the first capacitor C1 can be mounted, and is a position where the conductor pattern extending from the substrate positive connection portion CN + is connected to the first capacitor C1. The 4 th position refers to a position where the second capacitor C2 can be mounted, and is a position where the conductor pattern extending from the substrate negative connection portion CN-is connected to the second capacitor C2. In this case, the circuit board 200 can form a current loop including the through hole 204 d. The current loop with the through hole 204d is smaller than the current loop without the through hole 204.

In addition, in fig. 10, the direction in which the driving power supply mounting holes 206a and 206b are connected is set to the 1 st direction, but the 2 nd direction in which the first capacitor C1 and the second capacitor C2 are connected may be a direction different from the 1 st direction.

Fig. 11 is a diagram for explaining a region where the through-hole 204d can be formed. At least a part of the through-hole 204d may be formed in an area 500A surrounded by the outer end portions 206a #1 and 206b #1 of the driving power mounting hole 206a and 206b #1, the outer end portion C1#1 of the first capacitor C1, and the outer end portion C2#1 of the second capacitor C2. In this case, the circuit board 200 can form a current loop including the through hole 204 d. The current loop with the through hole 204d is smaller than the current loop without the through hole 204.

Fig. 12 is a diagram for explaining another region where the through-hole 204d can be formed. At least a part of the through-hole 204d may be formed in a region 500B surrounded by the inner end 206a #2 of the driving power supply mounting hole 206a and the inner end 206B #2 of the driving power supply mounting hole 206B, the inner end C1#2 of the first capacitor C1, and the inner end C2#2 of the second capacitor C2. In this case, the circuit board 200 can form a current loop including the through hole 204 d. The current loop with the through hole 204d is smaller than the current loop without the through hole 204.

Fig. 13 is a perspective view showing an example of a substrate mounting unit 300 according to a modification. The board mounting unit 300 includes a projection 310 instead of the screw hole 302 d. The convex portion 310 is formed of a conductor. Preferably, the convex portion 310 is connected to the GND potential. The convex portion 310 blocks, for example, the screw hole 302d, and is attached to the surface of the blocked screw hole 302 d. For example, in the case where the circuit board 200 is mounted on the board mounting unit 300, the convex portion 310 is electrically connected to the first capacitor C1 and the second capacitor C2. In addition, in the case where a conductor electrically connected to the first capacitor C1 and the second capacitor C2 is formed on the inner wall of the through-hole 204d, the convex portion 310 may be electrically connected to the conductor. In this case, the circuit board 200 can form a current loop including the through hole 204 d. The current loop with the through hole 204d is smaller than the current loop without the through hole 204.

The present invention can be used for, for example, a circuit board and a control device.

The features of the above-described preferred embodiments and modifications thereof may be appropriately combined as long as no conflict arises.

Although preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the invention is, therefore, indicated by the appended claims.