JP5912430B2 - Electronic control unit for electric power steering - Google Patents

Description

  The present invention relates to an electronic control unit for electric power steering and the like.

  A vehicle such as an automobile can include an electric power steering device, and the electric power steering device generates an auxiliary torque that assists a steering torque in a steering system generated by an operation by a driver on the steering handle. Due to the generation of the auxiliary torque, the electric power steering apparatus can reduce the burden on the driver. The auxiliary torque mechanism that provides the auxiliary torque detects the steering torque of the steering system with the steering torque sensor, generates a drive signal with the electronic control unit based on the detection signal, and generates the auxiliary torque according to the steering torque based on the drive signal. Generated by the electric motor and transmits the auxiliary torque to the steering system via the speed reduction mechanism.

  For example, Patent Document 1 discloses the structure of an electronic control unit for electric power steering. The motor control device 200 (electronic control unit) in FIG. 3 of Patent Document 1 is formed integrally with the motor 100 on the side portion of the motor 100.

JP 2010-63242 A

  In general, it is desirable that the electronic control unit for electric power steering be small. However, it is difficult for those skilled in the art to design an electronic control unit for a small electric power steering.

  One object of the present invention is to provide a small electronic control unit for electric power steering. Other objects of the present invention will become apparent to those skilled in the art by referring to the aspects and preferred embodiments exemplified below and the accompanying drawings.

  In the following, in order to easily understand the outline of the present invention, embodiments according to the present invention will be exemplified.

A first aspect according to the present invention is an electronic control unit for electric power steering formed integrally with an electric motor,
A first substrate having a switching circuit for supplying a drive signal to the electric motor;
A second substrate having an electrolytic capacitor for smoothing the power supply voltage that is the source of the drive signal;
A third substrate having a control circuit for controlling the switching circuit;
A unit cover for storing the first substrate, the second substrate, and the third substrate;
With
The opening of the unit cover is closed by a motor cover that houses the electric motor,
The first substrate, the second substrate, the third substrate, and the motor cover are arranged in the direction of the motor shaft of the electric motor, the motor cover, the third substrate, the second substrate, and the The electronic control unit for electric power steering is characterized by being arranged in the order of the first substrate.

  Since the opening of the unit cover is closed by the motor cover that houses the electric motor, the electronic control unit needs to include a lid (for example, the metal casing 240 in FIG. 1 of Patent Document 1) that is an independent component. Absent. By reducing the number of parts constituting the electronic control unit, a small electronic control unit for electric power steering can be provided.

  Furthermore, the first substrate, the second substrate, the third substrate, and the motor cover are arranged in the order of the motor cover, the third substrate, the second substrate, and the first substrate in the direction of the motor shaft of the electric motor. Be placed. Accordingly, the electronic control unit can be formed integrally with the electric motor at the upper part or the lower part of the electric motor. The switching circuit can be arranged above or below the electrolytic capacitor, and the protruding of the electronic control unit can be suppressed, and a small electronic control unit for electric power steering can be provided. Therefore, when the electronic control unit and the electric motor are incorporated in the electric power steering apparatus, the degree of freedom in arrangement or design is high.

  In FIG. 2 of Patent Document 1, the motor control device 200 (electronic control unit) is formed integrally with the motor 100 on the side of the motor 100, and the motor control device 200 itself forms a ledge as a whole. Therefore, when the motor control device 200 and the motor 100 are incorporated in the electric power steering device, the degree of freedom of arrangement or design is limited. Furthermore, in FIG. 1, FIG. 5 and FIG. 11 of Patent Document 1, the DC module 230 or the electrolytic capacitors C2 and C3 are arranged on the left or right with respect to the power module 210, and the DC module 230 or the electrolytic capacitors C2 and C3 are As a result, the motor control device 200 is protruded or enlarged.

  In the first aspect, the third substrate may include a magnetic sensor that detects a rotation angle of the electric motor.

  The magnetic sensor can be brought close to the electric motor, in other words, the magnetic sensor can be opposed to the electric motor without passing through the first substrate and the second substrate. A control unit can be provided.

  If the magnetic sensor faces the electric motor via the first substrate and the second substrate, it is necessary to form holes in the first substrate and the second substrate in order to detect the rotation angle of the electric motor. There is. Due to this hole, the areas of the first substrate and the second substrate are increased, and the electronic control unit is prevented from being downsized.

In the first aspect, the switching circuit may include a plurality of switching transistors,
A plurality of signal lines carrying a plurality of control signals sent from the control circuit to the plurality of switching transistors may be connected to the first substrate in a row.
The plurality of switching transistors may be arranged according to the one column.

  The distance between the plurality of switching transistors and one column (a plurality of signal lines) can be shortened, and the area of the first substrate can be reduced. Accordingly, a small electronic control unit for electric power steering can be provided.

  The lead frame SLF in FIG. 1 of Patent Document 1 is connected to the side of the substrate of the power module 210, and as shown in FIG. 9 of Patent Document 1, the power for connecting the switching element SSW and the lead frame SLF. The route or area of the wiring pattern on the substrate of the module 210 is large, and the entire power module 210 is also large.

  In the first aspect, the plurality of signal lines may bypass the electrolytic capacitor, pass through the second substrate, and be connected to the side portion of the third substrate in a row.

  By arranging a plurality of signal lines by effectively using the space between the first substrate and the third substrate, a small electronic control unit for electric power steering can be provided.

In the first aspect, the first substrate and the second substrate may be fastened together with a male screw portion and a female screw portion,
The female thread portion may be provided on the unit cover,
The male screw part may be connected to the female screw part through a tube for positioning the first substrate and the second substrate.

  The male screw portion and the unit cover can sandwich the first board and the second board, and can provide a small electronic control unit for electric power steering. If only the first substrate and the second substrate are fixed independently, and only the first substrate and the unit cover are fixed independently, the number of parts constituting the male screw portion and the female screw portion is reduced. It will increase.

  Those skilled in the art will readily understand that the illustrated embodiments according to the present invention can be further modified without departing from the spirit of the present invention.

The example of schematic structure of an electric power steering device is shown. 1 shows an external appearance example of an electronic control unit for electric power steering according to the present invention. An example of the disassembled perspective view of the electronic control unit containing the unit cover of FIG. 2 is shown. FIG. 4 shows an example of a circuit configuration diagram showing a connection relationship between the switching circuit of FIG. 3 and an electrolytic capacitor. An example of the functional block diagram of the 3rd board | substrate of FIG. 3 is shown. 6A shows a plan view of the first substrate in FIG. 3, FIG. 6B shows a plan view of the first substrate to which the relay member is attached, and FIG. FIG. 6D is a plan view of the relay member from which the skeleton of FIG. 3 is omitted. FIG. 7A is a diagram illustrating the arrangement of the first substrate, the plurality of signal lines, the electrolytic capacitor, and the third substrate in FIG. 3, and FIG. 7B is a bus bar of the second substrate in FIG. FIG. 7C is a diagram illustrating the arrangement of the electrolytic capacitor and the coil, and FIG. 7C is a diagram illustrating the arrangement of the first board, the relay member, the pipe 292, the second board, and the male screw in FIG.

  The preferred embodiments described below are used to facilitate an understanding of the present invention. Accordingly, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.

  FIG. 1 shows a schematic configuration example of an electric power steering apparatus 10. In the example of FIG. 1, the electric power steering apparatus 10 includes an electronic control unit (also referred to as a control unit) 42 for electric power steering. Specifically, the electric power steering device 10 provides auxiliary torque (also referred to as additional torque) to the steering system 20 from the steering handle (for example, steering wheel) 21 of the vehicle to the steering wheels (for example, front wheels) 29 and 29 of the vehicle. An auxiliary torque mechanism 40 is provided.

  In the example of FIG. 1, the steering system 20 connects a rotating shaft 24 (also referred to as a pinion shaft or an input shaft) to a steering handle 21 via a steering shaft 22 (also referred to as a steering column) and universal shaft joints 23 and 23. The rack shaft 26 is connected to the rotary shaft 24 via a rack and pinion mechanism 25, and left and right steering are connected to both ends of the rack shaft 26 via left and right ball joints 52, 52, tie rods 27, 27 and knuckles 28, 28. The wheels 29 and 29 are connected. The rack and pinion mechanism 25 includes a pinion 31 provided on the rotary shaft 24 and a rack 32 provided on the rack shaft 26.

  According to the steering system 20, when the driver steers the steering handle 21, the steering wheels 29 and 29 can be steered via the rack and pinion mechanism 25 by the steering torque.

  In the example of FIG. 1, the auxiliary torque mechanism 40 detects the steering torque of the steering system 20 applied to the steering handle 21 with a steering torque sensor 41, and the electronic control unit 42 based on this detection signal (also referred to as a torque signal). A drive signal is generated, an auxiliary torque (additional torque) corresponding to the steering torque is generated by the electric motor 43 based on the drive signal, and the auxiliary torque is transmitted to the rotating shaft 24 via a speed reduction mechanism 44 (for example, a worm gear mechanism). Further, the auxiliary torque is transmitted from the rotary shaft 24 to the rack and pinion mechanism 25 of the steering system 20.

  The electric power steering apparatus 10 can be classified into a pinion assist type, a rack assist type, a column assist type, and the like, depending on the location where the auxiliary torque is applied to the steering system 20. Although the electric power steering apparatus 10 of FIG. 1 shows a pinion assist type, the electric power steering apparatus 10 may be applied to a rack assist type, a column assist type, or the like.

  The electric motor 43 is, for example, a brushless motor, and the rotation angle of the rotor in the brushless motor or the rotation angle of the electric motor 43 (also referred to as a rotation signal) is detected by the electronic control unit 42. The rotor is composed of, for example, a permanent magnet, and the electronic control unit 42 can detect the movement of the permanent magnet (N pole and S pole) with a magnetic sensor.

  The electronic control unit 42 includes, for example, a power supply circuit, a current sensor that detects a motor current (actual current), a microprocessor, an FET bridge circuit, a magnetic sensor, and the like. The electronic control unit 42 can input not only a torque signal but also a vehicle speed signal, for example. The external device 60 is, for example, a vehicle speed sensor, but may be another electronic control unit that can communicate through an in-vehicle network such as a CAN (Controller Area Network). The microprocessor can perform vector control of the electric motor 43 based on a torque signal, a vehicle speed signal, and the like. The FET bridge circuit controlled by the microprocessor includes, for example, a switching circuit 111, FET1, FET2, FET3, FET4, FET5, FET6 (FIG. 4) that supplies a drive current (three-phase alternating current) to the electric motor 43 (brushless motor). Reference). The magnetic sensor is configured by, for example, a Hall IC 310 (see FIG. 3).

  Such an electronic control unit 42 sets a target current based at least on the steering torque (torque signal), and preferably the vehicle speed (vehicle speed signal) detected by the vehicle speed sensor and the rotation angle of the rotor detected by the magnetic sensor. The target current is set in consideration of (rotation signal). The electronic control unit 42 can control the drive current (drive signal) of the electric motor 43 so that the motor current (actual current) detected by the current sensor matches the target current.

  According to the electric power steering device 10, the steering wheels 29 and 29 can be steered by the rack shaft 26 by a combined torque obtained by adding the auxiliary torque (additional torque) of the electric motor 43 to the steering torque of the driver.

  FIG. 2 shows an example of the appearance of an electronic control unit for electric power steering according to the present invention. In the example of FIG. 2, the unit cover 420 is a cover of the electronic control unit 42 of FIG. 1, and the motor cover 430 is a cover of the electric motor 43 of FIG. The electronic control unit 42 is formed integrally with the electric motor 430 so that the unit cover 420 is disposed in the direction of the motor shaft 450 of the electric motor 43. In the example of FIG. 2, when the direction DR <b> 1 points above the electric motor 43, the electronic control unit 42 can be formed integrally with the electric motor 43 on the electric motor 43. The external connector 440 protrudes in the direction of the motor shaft 450 (direction DR1) and has at least one terminal 460 (see FIG. 3) that connects the steering torque sensor 41 and the like to the electronic control unit 42.

  FIG. 3 shows an example of an exploded perspective view of the electronic control unit 42 including the unit cover 420 of FIG. In the example of FIG. 3, the electronic control unit 42 for electric power steering includes a first substrate 100, a second substrate 200, a third substrate 300, and a unit cover 420. The first substrate 100 includes a switching circuit 110 that supplies a drive signal to the electric motor 43. The second substrate 200 has at least one electrolytic capacitor 210 that smoothes the power supply voltage that is the source of the drive signal. The third substrate 300 includes a control circuit (see FIG. 5) that controls the switching circuit 110. The unit cover 420 can store the first substrate 100, the second substrate 200, and the third substrate 300. The opening 425 of the unit cover 420 is closed by the motor cover 430 (see FIG. 2). The opening 425 is an opening at the top of the unit cover 420, the opening 426 is an opening at the side of the unit cover 420, and the opening 426 is closed by a plate-shaped lid 428 and a male screw 429. (See FIG. 2).

  Since the opening 425 of the unit cover 420 is closed by the motor cover 430, the electronic control unit 42 does not need to include a lid (for example, the metal casing 240 in FIG. 1 of Patent Document 1) that is an independent component. . By reducing the number of parts constituting the electronic control unit 42, it is possible to provide a small electronic control unit 42 for electric power steering. Note that the opening 426 of the unit cover 420 corresponds to, for example, the cover 250M of FIG.

  In FIG. 2 of Patent Document 1, the motor control device 200 (electronic control unit) is formed integrally with the motor 100 on the side of the motor 100, and the motor control device 200 itself forms a ledge as a whole. Therefore, when the motor control device 200 and the motor 100 are incorporated in the electric power steering device, the degree of freedom of arrangement or design is limited. Furthermore, in FIG. 1, FIG. 5 and FIG. 11 of Patent Document 1, the DC module 230 or the electrolytic capacitors C2 and C3 are arranged on the left or right with respect to the power module 210, and the DC module 230 or the electrolytic capacitors C2 and C3 are As a result, the motor control device 200 is protruded or enlarged.

  Referring to FIG. 3 showing the electronic control unit 42 and FIG. 2 showing the motor cover 430, the first substrate 100, the second substrate 200, the third substrate 300, and the motor cover 430 are the motor shaft of the electric motor 43. The motor cover 430, the third substrate 300, the second substrate 200, and the first substrate 100 are arranged in this order in the direction 450 (direction DR1). When the direction DR1 points upward, the switching circuit 110 can be disposed above the at least one electrolytic capacitor 210, and the protrusion of the electronic control unit 42 can be suppressed to provide a small electronic control unit 42. it can. Therefore, when the electronic control unit 42 and the electric motor 43 are incorporated into the electric power steering apparatus 10 or the speed reduction mechanism 44, the degree of freedom in arrangement or design is high.

  In the example of FIG. 3, the external connector 440 can be fixed to the unit cover 420 via at least one male screw 490. The relay member 150 includes a plurality of signal lines 160 that carry a plurality of control signals for controlling the switching circuit 110. With the relay member 150 attached to the first substrate 100, the plurality of signal lines 160 are The connection region 162 of the first substrate 100 can be fixed by being connected with, for example, solder. The tube 292 positions the first substrate 100 and the second substrate 200, and the first substrate 100 and the second substrate 200 are unitized via at least one male screw 290 and at least one female screw 291. The cover 420 can be fixed. The at least one male screw 290 can be coupled to the at least one female screw 291 through the at least one hole 294, the at least one tube 292, and the at least one hole 293.

  The plurality of signal lines 160 can penetrate through the second substrate 200 and also through the plurality of holes in the connection region 161. The at least one terminal 460 can penetrate the second substrate 200 and also penetrate at least one hole of the connection region 461. The third substrate 300 can be fixed to the unit cover 420 via at least one male screw 390 and at least one female screw 391. The plurality of signal lines 160 and the at least one terminal 460 are connected to the third substrate. It can be fixed to 300 with solder, for example.

  The third substrate 300 includes a Hall IC 310 that uses, for example, a Hall element as a magnetic sensor, and the Hall IC 310 can be brought close to the electric motor 43. In other words, the Hall IC 310 can face the motor cover 430 or the electric motor 43 without passing through the first substrate 100 and the second substrate 200, and a small electronic control unit 42 can be provided. .

  If the Hall IC 310 faces the motor cover 430 or the electric motor 43 via the first substrate 100 and the second substrate 200, the first substrate 100 and the first substrate 100 are detected in order to detect the rotation angle of the electric motor 43. It is necessary to form a hole corresponding to the Hall IC 310 in the second substrate 100. Due to this hole, the areas of the first substrate 100 and the second substrate 200 are increased, and the electronic control unit 42 is prevented from being downsized.

  FIG. 4 shows an example of a circuit configuration diagram showing a connection relationship between the switching circuit 111 of FIG. 3 and at least one electrolytic capacitor 210. In the example of FIG. 4, for example, B + indicates the potential of the positive electrode of a battery or DC power supply provided in the vehicle, B− indicates the potential of the negative electrode of the battery, and the negative potential B− is grounded to the vehicle body of the vehicle. can do. The positive electrode potential B + is the same as the bus bar potential B + of the external connector 440 and the bus bar potential B + of the second substrate 200, and the negative electrode potential B− is the same as the bus bar potential B− of the external connector 440 and the second potential. It is the same as the potential B− of the bus bar of the second substrate 200. The external connector 440 can supply power from the battery to the electronic control unit 42, and the bus bar of the external connector 440 and the bus bar of the second substrate 200 can be fixed by welding, for example.

  In the example of FIG. 4, the switching circuit 111 is a three-phase FET bridge circuit FET1 to FET6 composed of six FET1 to FET6, and at least one electrolytic capacitor for the positive potential B + and the negative potential B−. 210 is connected in parallel. The switching circuit 111 may be composed of a plurality of switching transistors (for example, IGBT) other than the FET. Note that at least one electrolytic capacitor 210 is constituted by, for example, four electrolytic capacitors (see FIG. 3).

  The FET 1 and FET 2 are connected in series between the positive potential B + and the negative potential B−, and can generate a U-phase current flowing through, for example, the U winding of the electric motor 43. As a current sensor for detecting the U-phase current, for example, a shunt resistor R1 can be provided between the FET2 and the negative potential B-, and as a semiconductor relay capable of interrupting the U-phase current, for example, the FET7 is connected between the FET1 and the FET2. It can be provided between the connection node and the output terminal U to the electric motor 43.

  The FET 3 and the FET 4 are connected in series between the positive potential B + and the negative potential B−, and can generate a V-phase current flowing through, for example, the V winding of the electric motor 43. As a current sensor for detecting the V-phase current, for example, a shunt resistor R2 can be provided between the FET 4 and the negative potential B-, and as a semiconductor relay capable of interrupting the V-phase current, for example, the FET 8 is connected between the FET 3 and the FET 4. It can be provided between the connection node and the output terminal V to the electric motor 43.

  The FET 5 and the FET 6 are connected in series between the positive potential B + and the negative potential B−, and can generate a W-phase current flowing through, for example, the W winding of the electric motor 43. As a current sensor for detecting the W phase current, for example, a shunt resistor R3 can be provided between the FET 6 and the negative potential B-, and as a semiconductor relay capable of interrupting the W phase current, for example, the FET 9 is connected between the FET 5 and the FET 6. It can be provided between the connection node and the output terminal W to the electric motor 43.

  In the example of FIG. 4, the switching circuit 110 can supply a U-phase current, a V-phase current, and a W-phase current as drive signals to the electric motor 43, and at least one electrolytic capacitor 210 is a source of the drive signal. The power supply voltage (the difference between the positive electrode potential B + and the negative electrode potential B-) can be smoothed. The FET1, FET3, and FET5 are connected to the positive potential B + via, for example, the FET 10 and FET11 as semiconductor relays capable of cutting off the power from the battery, and the noise filter, for example, via the coil 220. Each of FET1 to FET11 has a gate (not shown) connected to a corresponding one of the plurality of signal lines 160, and is turned on or off.

  For example, three corresponding signal lines among the plurality of signal lines 160 are connected to a connection node between the FET 2 and the shunt resistor R1, a connection node between the FET 4 and the shunt resistor R2, and a connection node between the FET 6 and the shunt resistor R3. Thus, the U-phase current, the V-phase current and the W-phase current can be obtained from the potentials of these connection nodes.

  The FET1 to FET11 and the shunt resistor R1 to the shunt resistor R3 in FIG. 4 are provided on the first substrate 100 in FIG. 3, and the output terminals U, V, and W in FIG. 4 are the output terminals U of the relay member 150 in FIG. , V, and W, at least one electrolytic capacitor 210 of FIG. 4 is provided on the second substrate 200 of FIG. The first substrate 100 is made of, for example, a metal substrate, and the unit cover 420 is made of, for example, metal. For example, grease is interposed between the first substrate 100 and the unit cover 420, and the first substrate 100 ( The heat dissipation of the power board can be improved. Further, by adopting the semiconductor relay in the FET7 to FET11, the overall height of the first substrate 100 can be reduced, and the small electronic control unit 42 can be provided.

  FIG. 5 shows an example of a functional block diagram of the third substrate 300 of FIG. In the example of FIG. 5, the control circuit includes a microprocessor and a drive circuit, and the third substrate 300 can include not only the Hall IC 310 but also a control circuit, an input circuit, and a power supply circuit. In FIG. 3, the control circuit, the input circuit, and the power supply circuit are not shown and are omitted.

  The control circuit controls at least the switching circuit 110 (FET1 to FET6), and the microprocessor can set the target current. The target current is set by a torque signal and motor current (actual current) taken in via the input circuit, a rotation signal taken in via the Hall IC 310, and the like. The drive circuit generates six control signals (gate signals) corresponding to the FET1 to FET6 based on the target current. The FET1 to FET6 are turned on or off by six control signals (gate signals), whereby a drive signal (drive current) is supplied to the electric motor 43.

  The control circuit can also control the semiconductor relays (FET7 to FET11). In this case, the microprocessor determines whether each of the FET7 to FET11 is turned on or off, and the drive circuit can generate five control signals (gate signals) corresponding to the FET7 to FET11 based on these determinations. it can.

  A plurality of signal lines 160 in FIG. 3 not only carry gate signals corresponding to FET1 to FET11 but also carry signals indicating the potentials of the shunt resistors R1 to R3, and further, positive and negative potentials B + and B−. Can also carry a signal indicating. The power supply circuit in FIG. 5 is connected to two corresponding signal lines among the plurality of signal lines 160, and can generate power for the Hall IC 310, the input circuit, the microprocessor, and the drive circuit. In other words, the power supply circuit can convert the battery power supply voltage (the difference between the positive potential B + and the negative potential B−) into the logic power supply voltage (the difference between the potential V and the potential GND).

  6A is a plan view of the first substrate 100 of FIG. 3, FIG. 6B is a plan view of the first substrate 100 to which the relay member 150 is attached, and FIG. ) Shows a plan view of the relay member 150 of FIG. 3, and FIG. 6D shows a plan view of the relay member 150 with the skeleton of FIG. 3 omitted.

  In the example of FIG. 6A, the six FET1 to FET6 constituting the switching circuit 111 are arranged and arranged by the connection region 162. Specifically, the FET1, FET3, and FET5 (Hi Side FET) on the positive potential B + side have three FET7, FET8, and FET9 sides constituting a semiconductor relay that can cut off U-phase current, V-phase current, and W-phase current. On the other hand, FET2, FET4, FET6 (Low Side FET) on the negative potential B- side are arranged on the shunt resistors R1, R2, R3 side.

  In the example of FIG. 6B, the plurality of signal lines 160 are connected to the first substrate 100 in a row in the connection region 162. By arranging one column (a plurality of signal lines 160) between FET1, FET3, FET5 and FET7, FET8, FET9, six FET1 to FET6 and one column (6 corresponding to FET1 to FET6) The distance from the six signal lines 160) carrying control signals (gate signals) can be shortened, and the area of the first substrate 100 can be reduced. Therefore, a small electronic control unit 42 can be provided.

  The lead frame SLF in FIG. 1 of Patent Document 1 is connected to the side of the substrate of the power module 210, and as shown in FIG. 9 of Patent Document 1, the power for connecting the switching element SSW and the lead frame SLF. The route or area of the wiring pattern on the substrate of the module 210 is large, and the entire power module 210 is also large.

  In the example of FIG. 6C, the skeleton of the relay member 150 connects a plurality of signal lines 160, output terminals U, V, W to the electric motor 43, the first substrate 100 and the second substrate 200. The connection terminals H1, H2, L1, L2, and L3 and the pipes 292, 292, 292, and 292 are formed by molding with resin, for example. The output terminals U, V, and W are connected to FET7, FET8, and FET9, respectively (see FIG. 4). The connection terminals H1, H2, and H3 of the relay member 150 are connected to the positive potential B + line on the first substrate 100, and the connection terminals L1 and L2 of the relay member 150 are connected to the first substrate 100. It is connected to the negative potential B- line (see FIG. 4). In the example of FIG. 6D, the skeleton (resin) of the relay member 150 is omitted.

  7A shows an arrangement explanatory view of the first substrate 100, the plurality of signal lines 160, at least one electrolytic capacitor 210, and the third substrate 300 of FIG. 3, and FIG. 7B shows the arrangement of FIG. FIG. 7C is a diagram illustrating the arrangement of the four bus bars, the at least one electrolytic capacitor 210, and the coil 220 of the second substrate 200, and FIG. 7C illustrates the first substrate 100, the relay member 150, and at least one of the first substrate 100 of FIG. The arrangement | positioning explanatory drawing of the pipe | tube 292, the 2nd board | substrate 200, and the at least 1 external thread 290 is shown.

  In the example of FIG. 7A, the plurality of signal lines 160 bypass four electrolytic capacitors 210 in real space. In addition, the plurality of signal lines 160 are connected to the connection region 162 in the central portion of the first substrate 100 so as to be aligned in one column, and are connected to the connection region in the side portion of the first substrate 100 aligned in one column. 161 is also connected. By arranging the plurality of signal lines 160 by effectively using the space between the first substrate 100 and the third substrate 300, a small electronic control unit 42 can be provided.

  In the example of FIG. 7B, the bus bar (potential B +) of the second substrate 200 corresponding to the bus bar (potential B +) of the external connector 440 is connected to one end of the coil 220. The bus bar (potential H1) of the second substrate 200 connected to the other end of the coil 220 and the connection terminal H1 of the relay member 150 in FIG. 6C can be fixed by welding, for example. One end (potential H2) and the other end (potential H3) of the bus bar of the second substrate 200 connected to one end on the potential B + side of the positive electrodes of the four electrolytic capacitors 210 are respectively connected to the relay member 150 in FIG. The connection terminals H2 and H3 are fixed by welding, for example. The first end (potential L1), the second end (potential L2), and the third end (potential L2) of the bus bar of the second substrate 200 connected to the other end of the negative electrode B-side of the four electrolytic capacitors 210. The potential B−) is fixed to the connection terminals L1 and L2 of the relay member 150 and the bus bar (potential B−) of the external connector 440 by welding, for example, in FIG.

  With such an arrangement, between the four electrolytic capacitors 210 of the second substrate 200 and the switching circuit 111 of the first substrate 100, for example, two connection terminals H2 and H3 of the relay member 150 on the potential B + side of the positive electrode. Are connected via the connection terminals L1 and L2 of the relay member 150 on the negative potential B− side. As a result, the line impedance can be lowered, and a surge generated during the operation of the switching circuit 111 can be suppressed.

  In the example of FIG. 7C, the first substrate 100 and the second substrate 200 are fastened together with at least one male screw portion such as a male screw 290 and at least one female screw portion such as a female screw 291. . Since the at least one female screw 291 is provided in the unit cover 420, the at least one male screw 290 and the unit cover 420 can sandwich the first substrate 100 and the second substrate 200, and can be used as a small electronic device. A control unit 42 can be provided. If only the first substrate 100 and the second substrate 200 are fixed independently, and only the first substrate 100 and the unit cover 420 are fixed independently, a male screw portion and a female screw portion are formed. The number of parts will increase. In addition, when tightening at least one male screw 290, for example, the plurality of signal lines 160, output terminals U, V, W and connection terminals H1, H2, L1, L2, L3 of the relay member 150 in FIG. No torsional stress is applied, and the reliability when electrically connecting the first substrate 100 and the second substrate 200 can be improved.

  The present invention is not limited to the above-described exemplary embodiments, and those skilled in the art will be able to easily modify the above-described exemplary embodiments to the extent included in the claims. .

  DESCRIPTION OF SYMBOLS 10 ... Electric power steering device, 20 ... Steering system, 21 ... Steering handle, 22 ... Steering shaft, 23 ... Universal shaft joint, 24 ... Rotary shaft, 25 ... Rack And pinion mechanism, 26 ... rack shaft, 27 ... tie rod, 28 ... knuckle, 29 ... steering wheel, 31 ... pinion, 32 ... rack, 40 ... auxiliary torque mechanism, 41 ... steering torque sensor, 42 ... electronic control unit (control unit), 43 ... electric motor, 44 ... deceleration mechanism, 52 ... ball joint, 60 ... external device, 100. ..First substrate 110... Switching circuit 150. Relay member 160. Signal line 161 and 162 connection region 200 second substrate 210. Electrolytic capacitor, 220 ... coil, 290 ... male screw, 291 ... female screw, 292 ... tube, 293, 294 ... hole, 300 ... third substrate, 310 ... Hall IC, 390 ... male screw, 391 ... female screw, 420 ... unit cover, 425, 426 ... opening, 428 ... lid, 429 ... male screw, 430 ... Motor cover, 440 ... external connector, 450 ... motor shaft, 460 ... terminal, 461 ... connection region, 490 ... male screw.

Claims (4)

An electronic control unit for electric power steering formed integrally with an electric motor,
A flat first substrate having a switching circuit for supplying a drive signal to the electric motor;
A flat second substrate having an electrolytic capacitor for smoothing the power supply voltage that is the source of the drive signal;
A flat third substrate having a control circuit for controlling the switching circuit and a magnetic sensor for detecting a rotation angle of the electric motor ;
A unit cover for storing the first substrate, the second substrate, and the third substrate;
With
The opening of the unit cover is closed by a motor cover that houses the electric motor,
The first substrate, the second substrate, the third substrate, and the motor cover are arranged in the direction of the motor shaft of the electric motor, the motor cover, the third substrate, the second substrate, and the An electronic control unit for electric power steering, which is arranged in the order of the first substrate. The switching circuit has a plurality of switching transistors,
A plurality of signal lines carrying a plurality of control signals sent from the control circuit to the plurality of switching transistors are connected to the first substrate side by side in one column,
The electronic control unit for electric power steering according to claim 1 , wherein the plurality of switching transistors are distributed and arranged by the one row. Said plurality of signal lines, the electrolyte bypasses the condenser through the second substrate, to be connected to claim 2, wherein the side portion of the third substrate side by side in a row The electronic control unit for electric power steering as described. The first substrate and the second substrate are fastened together with a male screw portion and a female screw portion,
The female screw portion is provided on the unit cover,
The said male screw part penetrates the pipe | tube which positions the said 1st board | substrate and the said 2nd board | substrate, and is connected with the said female screw part, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. Electronic control unit for electric power steering.

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