JP2023116049A - Driving device - Google Patents

Abstract

To provide a driving device that has a configuration in which circuit boards are arranged vertically and that can suppress increase in radial size even when larger-sized components are used.SOLUTION: A driving device 800 comprises a motor 80, a control unit 101, a heat sink 601, and a unit case 20. The heat sink 601 has a pillar part 610 that supports the control unit 101. In the pillar part 610, a pair of first arrangement parts 631 and 632 arranged on both sides of a rotation axis O, and one second arrangement part 641 connecting between the pair of first arrangement parts 631 and 632 are provided while facing radially outward. The unit case 20 is cylindrical and covers the control unit 101. The control unit 101 has circuit boards 301, 302, and 400. When a choke coil 33 and a capacitor 34, which are cylindrical electronic components that configure the control unit 10, are defined as large-sized components, a plurality of large-sized components are arranged in the unit case 20 so that axes of the cylinders are along an axial direction of the rotation axis O.SELECTED DRAWING: Figure 3

Description

The present invention relates to a driving device.

2. Description of the Related Art Conventionally, among driving devices in which a motor and a control unit are integrally provided, there has been known a driving device in which a power module and a circuit board of the control unit are arranged along the rotation axis direction. In such a configuration in which the circuit boards are "vertically arranged", it is possible to reduce the size in the radial direction.

For example, in the electric power steering apparatus disclosed in Patent Document 1, the heat sink has a rectangular parallelepiped column portion extending in the axial direction of the rotating shaft. Two sets of control boards and power modules that constitute two systems of motor drive circuits are respectively provided in a pair of arrangement portions corresponding to the two opposing surfaces of the column portion and in the arrangement portions corresponding to the other two opposing surfaces. are placed.

WO2019/073594

In this specification, a choke coil and a capacitor, which are cylindrical electronic parts that constitute a control unit, are defined as large-sized parts. In the device of Patent Document 1, the axis of the cylinder of the capacitor, which is a large component, is arranged so as to be orthogonal to the axial direction of the rotating shaft. Therefore, when using a capacitor of a larger size, there is a problem that it cannot be accommodated in the clearance space of the unit case (housing in Patent Document 1).

The present invention has been made in view of the above-described problems, and its object is to provide a drive structure in which circuit boards are arranged vertically, and which can suppress an increase in size in the radial direction even when using large components of a larger size. It is to provide a device.

The driving device according to the invention comprises a motor (80), a control unit (101, 102), a heat sink (601, 602) and a unit case (20). The motor includes a stator (84) and a rotor (86) rotating about a shaft (87) provided on an axis of rotation (O). The control unit is provided integrally with the motor on one side of the rotating shaft in the axial direction, and drives and controls the motor.

The heat sink has posts (610, 620) that support the control unit. The column has a pair of first placement portions (631, 632) arranged across the rotation axis, and one or a pair of second placement portions (641, 642) connecting the pair of first placement portions (641, 642). ) are provided facing radially outward. A cylindrical unit case covers the control unit supported by the column.

The control unit has one or more circuit boards (301, 302, 400, 401, 402) fixed to the first or second placement portion of the column.

A choke coil (33) and a capacitor (34), which are cylindrical electronic parts that constitute the control unit, are defined as large parts. A plurality of large-sized parts are arranged in the unit case with the axis of the cylinder along the axial direction of the rotating shaft. For example, at least some of the plurality of large-sized components are arranged in series along the axial direction of the rotating shaft. Furthermore, for example, one choke coil and one or more capacitors are arranged in series along the axial direction of the rotating shaft.

Although there is a restriction in the radial direction of the rotating shaft between the circuit board fixed to the column and the inner wall of the unit case, at least the longitudinal dimension of the board is secured in the axial direction of the rotating shaft. there is In the present invention, since the axes of the cylinders of a plurality of large-sized parts are arranged along the axial direction of the rotation shaft, even if a larger-sized large-sized part is used, it can be efficiently accommodated in the clearance space within the unit case. can.

1 is a schematic configuration diagram of an electric power steering device to which a driving device is applied; FIG. A circuit diagram of a two-path motor drive system. FIG. 2 is an axial cross-sectional view of the drive device according to the first embodiment; The IV direction arrow view of the column part of FIG. FIG. 4 is a view in the direction of arrow V in FIG. 3 ; 4 is a radial cross-sectional view taken along line VI-VI of FIG. 3; FIG. The side view of the heat sink of 1st Embodiment. VIII direction arrow directional view of FIG. FIG. 8 is a view in which a rotation angle sensor substrate is added to the IX direction arrow view of FIG. 7 ; The figure which shows the modification of 1st Embodiment which concerns on arrangement|positioning of a capacitor|condenser. FIG. 7 is an axial cross-sectional view of the drive device according to the second embodiment; FIG. 12 is a radial cross-sectional view taken along line XII-XII of FIG. 11; The disassembled side view of the heat sink of 2nd Embodiment. XIV direction arrow directional view of FIG. FIG. 14 is a diagram in which a rotation angle sensor substrate is added to the XV direction arrow view of FIG. 13 ; Radial direction sectional drawing of the drive device of a comparative example.

A plurality of embodiments of the drive device according to the invention will be described on the basis of the drawings. In a plurality of embodiments, substantially the same configurations are denoted by the same reference numerals, and descriptions thereof are omitted. The first and second embodiments are collectively referred to as "this embodiment". The driving device of the present embodiment is applied, for example, as a steering assist motor for an electric power steering device. This driving device is a so-called "machine-electrically integrated type" driving device in which a motor and a control unit for driving and controlling the motor are integrated. Further, in the driving device of this embodiment, the circuit board of the control unit is arranged along the rotation axis direction of the motor. Such arrangement of the circuit boards is called "vertical arrangement".

[Configuration of electric power steering device]
A schematic configuration of the electric power steering device 99 will be described with reference to FIG. Although FIG. 1 shows a rack-assist type electric power steering apparatus, the driving apparatus 800 of the present embodiment can also be applied to a column-assist type electric power steering apparatus. A steering system 90 including an electric power steering device 99 includes a steering wheel 91, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, an electric power steering device 99, and the like.

A steering shaft 92 to which a steering wheel 91 is connected is provided with a torque sensor 93 for detecting steering torque. A pinion gear 96 that meshes with a rack shaft 97 is provided at the tip of the steering shaft 92 . When the driver rotates the steering wheel 91 , the rotary motion of the steering shaft 92 is converted into linear motion of the rack shaft 97 by the pinion gear 96 . A pair of wheels 98 connected to both ends of the rack shaft 97 are steered to an angle corresponding to the amount of displacement of the rack shaft 97 .

The electric power steering device 99 includes a "mechanical and electrical integrated type" drive device 800 in which the motor 80 and the control unit 10 are integrated, and a reduction gear 89 that reduces the rotation of the motor 80 and transmits it to the rack shaft 97. . The motor 80 is a two-system three-phase brushless motor having two sets of three-phase windings, and the output shaft rotates about the rotation axis O. As shown in FIG.

The control unit 10 is provided integrally with the motor 80 on one side of the rotation axis O in the axial direction, and drives and controls the motor 80 . Motor 80 outputs steering assist torque by supplying three-phase AC power to two sets of three-phase windings from two systems of inverters in control unit 10 . A power system connector 23 of the control unit 10 is supplied with DC power from on-vehicle batteries BT1 and BT2. A sensor signal detected by an external torque sensor 93 is input to the signal system connector 24 via a harness 94 .

FIG. 2 shows the circuit configuration of the two-path motor drive system. The stator of motor 80 has two sets of windings 810,820. Power circuit 310 of the first system converts the power of first battery BT<b>1 and supplies power to first winding set 810 according to a command from control circuit 410 . Power circuit 320 of the second system converts the power of second battery BT<b>2 and supplies power to second winding set 820 in accordance with a command from control circuit 420 . Since the configurations of the power circuits 310, 320 and the control circuits 410, 420 of the first system and the second system are the same, the same reference numerals are given to the constituent elements of each system without distinction.

The two-system system shown in FIG. 2 is a "complete two-system" configuration in which power circuits 310 and 320 of each system are connected to individual batteries BT1 and BT2. On the other hand, the power circuits 310 and 320 of each system may be configured as a "dual drive system" in which the power circuits 310 and 320 are connected to a common battery. The power circuits 310, 320 include choke coils 33, power relays 35, reverse connection protection relays 36, capacitors 34, inverters 370, motor relays 381, 382, 383 and the like. In the following description, the reference numerals of the batteries BT1 and BT2 are omitted as appropriate.

The choke coil 33 , the power relay 35 and the reverse connection protection relay 36 are provided on the power line that connects the positive electrode of the battery and the high potential side of the inverter 370 . The capacitor 34 is, for example, an aluminum electrolytic capacitor, and is connected to the input side of the inverter 370 in parallel with the inverter 370 . Although the capacitors 34 of each system are indicated by one symbol in FIG. 2, a plurality of capacitors 34 may be connected in parallel and mounted so as to secure the capacity. The choke coil 33 and the capacitor 34 constitute an LC filter and function as a noise suppression element that reduces noise. In this specification, the choke coil 33 and the capacitor 34, which are cylindrical parts that constitute the control unit 10, are defined as "large parts".

The power relay 35 and the reverse connection protection relay 36 are composed of MOSFETs, for example. The parasitic diode of power relay 35 conducts current from the inverter 370 side to the battery side. When the battery is forwardly connected, the power supply relay 35 cuts off the current from the battery side to the inverter 370 side when the power relay 35 is OFF. A parasitic diode in the reverse connection protection relay 36 conducts current from the battery side to the inverter 370 side. When the battery is reversely connected, the reverse connection protection relay 36 cuts off current from the inverter 370 side to the battery side when it is OFF.

The inverter 370 includes a plurality of switching elements 371-376 of three-phase upper and lower arms, which are composed of MOSFETs, for example. Specifically, U-phase, V-phase, and W-phase upper arm switching elements 371, 372, and 373 and lower arm switching elements 374, 375, and 376 are bridge-connected. The switching elements 371 to 376 of the inverter 370 (hereinafter also referred to as “inverter elements 371 to 376”) are “heat generating elements” that generate heat when the motor 80 is energized.

In the configuration example of FIG. 2, shunt resistors are provided as current sensors for detecting phase currents on the ground side of the switching elements 374, 375, and 376 in the lower arms of the respective phases. The phase current detected by the current sensor is input to the microcomputer 43 and used for current feedback control and the like. The arrangement and configuration of the current sensors are not limited to the example of FIG. 2, and any known technique may be employed.

The motor relays 381 , 382 , 383 are composed of, for example, MOSFETs, and are provided in current paths that connect connecting points between the arms of each phase of the inverter 370 and the winding sets 810 , 820 . When the motor relays 381, 382, 383 are turned off, the reverse input from the motor 80 to the inverter 370 is blocked.

The control circuits 410 and 420 include the microcomputer 43 and the driver IC 45, and control driving of the inverter 370 based on the input signal. Signals such as the rotation angle of the motor 80 detected by the rotation angle sensor 53 and the steering torque of the driver detected by the external torque sensor 93 are input to the microcomputer 43 . The microcomputer 43 performs control calculations based on the input signal and outputs command signals to the driver IC 45 . The driver IC 45 outputs drive signals to the switching elements 371 to 376 of the inverter 370, the power relay 35, the reverse connection protection relay 36, and the motor relays 381, 382, and 383. Note that the microcomputers 43 of the two systems of control circuits 410 and 420 may communicate control information, abnormality information, etc. of each system with each other through inter-microcomputer communication to perform cooperative control.

[Configuration of drive device]
Next, a specific configuration of the driving device 800 will be described. In this embodiment, the circuit boards are "vertically arranged" along the axial direction of the rotation axis O. As shown in FIG. 2. Description of the Related Art Conventionally, as a driving device in which circuit boards are vertically arranged, one disclosed in Patent Document 1 (International Publication No. 2019/073594) is known. FIG. 16 shows a conventional configuration based on FIGS. 2 and 3 of Patent Document 1 as a comparative example. Although the reference numerals of Patent Document 1 are quoted as they are, they should not be confused with the reference numerals of the present embodiment because the letters "a" to "f" are added at the end.

In the driving device of the comparative example, the control boards 4a and 4b are arranged in a pair of arrangement portions 41d and 41e of the column portion 41b, and the power modules 50a and 50b are arranged in another pair of arrangement portions 41f and 41g. . The power modules 50a and 50b are configured by resin-sealing a plurality of switching elements that form an inverter circuit while being mounted on wiring. The smoothing capacitors 30a and 30b are fixed to the support members 45a and 45b and vertically stacked radially outward of the control boards 4a and 4b. The driving device of such a comparative example has the following problems [A]-[C].

[A] In the device of the comparative example, the heat sink includes a disk-shaped base portion and a rectangular parallelepiped column portion 41b standing upright at the center portion of the base portion. The base portion is provided inside the inner peripheral wall surface of the cylindrical portion of the motor. Control boards 4a and 4b and power modules 50a and 50b are arranged on a pair of arrangement portions 41d and 41e located on the four side surfaces of the column portion 41b and another pair of arrangement portions 41f and 41g. is entirely covered with a unit case (housing in patent document 1). That is, the heat sink does not have any part exposed to the outside. Therefore, the heat dissipation effect from the heat generating elements that generate heat when the motor is energized, such as the switching elements that constitute the inverter, is insufficient.

[B] In the device of the comparative example, the power modules 50a and 50b are attached in close contact with the heat sink via the signal lines 50c and 50d and the output terminals 51a and 51b. If the tight contact with the heat sink is lost due to vibration or the like due to an external force, there is a risk that the heat radiation effect from the power modules 50a and 50b will be reduced.

[C] In the device of the comparative example, the cylinder axes of the capacitors 30a and 30b, which are large components, are arranged so as to be orthogonal to the axial direction of the rotation shaft. Therefore, when using a capacitor of a larger size, there is a problem that it cannot be accommodated in the clearance space of the unit case (housing in Patent Document 1).

Therefore, the present embodiment provides a driving device that solves these problems with a configuration in which circuit boards are arranged vertically. That is, for problem A, the heat dissipation effect from the heating element is high, for problem B, the heat dissipation effect from the switching element that constitutes the inverter is high, and for problem C, even if a large-sized component is used, Provided is a driving device capable of suppressing an increase in size in the radial direction. In the following description of the effects of the configuration of the present embodiment, the symbols of the corresponding problems A to C are shown in parentheses.

(First embodiment)
The configuration of the driving device according to the first embodiment will be described with reference to FIGS. 3 to 9. FIG. 3 to 6 show the drive in assembled condition. 7 to 9 show a single heat sink 601, and FIG. 9 additionally shows a rotation angle sensor substrate 501. FIG. Here, the code of the heat sink in the first embodiment is "601", and the code of the control unit is "101". The driving device 800 mainly includes a motor 80 , a heat sink 601 , a control unit 101 and a unit case 20 .

The lower side of FIG. 3 corresponds to the front side where the output shaft of the motor 80 is provided, and the upper side of FIG. 3 corresponds to the rear side where the connector is provided. In the following description, the terms "upper" and "lower" may be used for convenience with reference to the viewing direction of FIG. The motor 80 includes a stator 84 and a rotor 86 housed in a motor case 83 . The motor case 83 is formed in a substantially bottomed cylindrical shape composed of a bottom portion 831 and a cylindrical portion 832, and the control unit 101 is provided on the opening side. A fastening receiving portion 837 used for fastening the heat sink 601 to the partition wall portion 70 is provided on the outer wall of the opening side of the cylindrical portion 832 .

The stator 84 has two sets of three-phase winding sets 810 and 820 wound around an iron stator core 845 fixed inside a cylindrical portion 832 of the motor case 83 . The stator core 845 is made of laminated steel plates or the like. A rotating magnetic field is formed in the stator 84 by energizing the winding sets 810 and 820 from the control unit 101 through the motor wire 85 .

The rotor 86 is provided with a plurality of permanent magnets 866 on the outer circumference of a rotor core 865 made of iron. The rotor core 865 is made of laminated steel plates or the like. The rotor 86 rotates around a shaft 87 provided on the rotation axis O by a rotating magnetic field formed in the stator 84 . A shaft 87 fixed to the rotor 86 is rotatably supported by a front bearing 873 held on the bottom 831 of the motor case 83 and a rear bearing 874 held on the partition wall 70 of the heat sink 601 . In the first embodiment, a sensor magnet 881 for detecting the rotation angle is attached to the rear end surface of the shaft 87 .

The heat sink 601 is made of aluminum alloy or the like. As shown in FIGS. 7 to 9, the heat sink 601 has a substantially rectangular parallelepiped column portion 610 and a plate-like partition wall portion 70 with the rotation axis O as the axis of symmetry. The columnar portion 610 of the heat sink 601 of the first embodiment has a hollow shape with a concave portion 649 formed on one surface.

The heat sink 601 in which the pillars 610 are hollow is suitable for manufacturing the pillars 610 and the partition walls 70 as an integral molding by casting or die casting. By using an integrally molded product, heat transfer is less likely to be interrupted, and efficient heat dissipation becomes possible (problem A). However, after the column portion 610 and the partition portion 70 are manufactured as two parts, they may be joined by welding or brazing.

A pair of first placement portions 631 and 632 and one second placement portion 641 for supporting the control unit 101 are provided on three side surfaces of the column portion 610 so as to face radially outward. A pair of first arrangement portions 631 and 632 are arranged in parallel with the rotation axis O interposed therebetween. One second placement portion 641 is orthogonal to the pair of first placement portions 631 and 632 and connects between the pair of first placement portions 631 and 632 . A connector-side end surface 65 , which is the end surface of the column portion 610 opposite to the motor 80 , faces the inner wall of the top plate portion 21 of the unit case 20 .

Support portions 67 to which the power circuit boards 301 and 302 are fixed protrude from the first arrangement portions 631 and 632 at a plurality of locations, that is, at four locations near both ends in the axial direction and the circumferential direction of the rotation axis O. there is Support portions 67 to which the control circuit board 400 is fixed protrude from the second placement portion 641 at two axial ends on the center line in the circumferential direction. The top surface of each support portion 67 is a flat seat surface 68 .

The surface of the second placement portion 641 on the side of the rotation axis O functions as an exposed heat dissipation surface 643 . As will be described later, the surface of the second placement portion 64 on the side of the rotation axis O corresponds to the surface opposite to the surface to which the control circuit board 400 is fixed. In the first embodiment, the heat dissipation surface 643 is ensured by forming the concave portion 649 in the column portion 610, so that the heat dissipation effect is improved (problem A).

The partition part 70 has a plate shape orthogonal to the rotation axis O, and separates the motor 80 and the control unit 101 in the axial direction of the rotation axis O. By isolating the motor 80 and the control unit 101 with the partition wall 70, the heat of both can be efficiently radiated (problem A). The upper surface 72 of the main body portion 71 of the partition wall portion 70 is connected to the column portion 610 side. A lower surface 73 of the body portion 71 faces the stator 84 and the rotor 86 of the motor 80 .

A shaft hole 75 into which the rear end of the shaft 87 is inserted is formed in the center of the partition 70 . A rotation angle sensor substrate 501 on which a rotation angle sensor 53 is mounted is installed directly above the shaft hole 75 at the bottom of the recess 649 of the column portion 610 . The rotation angle sensor 53 detects the rotation angle of the rotor 86 based on changes in the magnetic flux of a sensor magnet 881 attached to the rear end surface of the shaft 87 . A rotation angle signal detected by the rotation angle sensor 53 is transmitted to the microcomputer 43 via a rotation angle signal wiring 54 . A motor wire hole 76 through which a three-phase two-system motor wire 85 is inserted is formed outside the column portion 610 .

Fastening portions 77 for fastening with the motor case 83 are provided at a plurality of locations (for example, three locations) on the outer circumference of the main body portion 71 . The heat sink 601 and the motor 80 are fixed by screwing the screw 17 inserted through the screw hole 78 of the fastening portion 77 into the fastening receiving portion 837 of the motor case 83 .

An outer peripheral side surface 74 of the partition wall 70 is exposed to the outside. That is, in the comparative example, the entire heatsink is covered with other components, whereas in the present embodiment, the heatsink 601 is fixed to the motor 80 in a state in which a portion thereof is exposed to the outside. As a result, the heat of the heat generating elements such as the inverter elements 371 to 376 is efficiently released to the outside through the heat sink 601, so that a high heat dissipation effect can be obtained (problem A).

Next, the control unit 101 will be explained. To describe all embodiments generically, the control unit 10 comprises "one or more circuit boards fixed to the first or second arrangement of the pillars of the heat sink". The control unit 101 has three circuit boards 301, 302, 400 in the first embodiment, and the control unit 102 has four circuit boards 301, 302, 401, 402 in the second embodiment. Note that the “circuit board” does not include the rotation angle sensor board 501 . The three circuit boards in the first embodiment are two power circuit boards 301 and 302 and one control circuit board 400 . Heating elements are mounted on at least the power circuit boards 301 and 302 as "at least one circuit board".

FIG. 4 shows a mounting layout of the power circuit board 301 of the first system. Since the mounting layout of the power circuit board 302 of the second system is similar, the power circuit board 301 of the first system will be described as an example with reference to FIG. A power circuit board 301 of the first system is mounted with a plurality of switching elements 371 to 376 constituting an inverter 370 in a power circuit 310 that supplies power to the motor 80 . The upper arm elements 371-373 of each phase are connected to the power terminal 25p of the power system connector 23 via the power line 27p. The lower arm elements 374-376 of each phase are connected to the ground terminal 25g of the power system connector 23 via the ground line 27g.

In addition, a power relay 35 and a reverse connection protection relay 36 are mounted on the power line 27p, and motor relays 381, 382, and 383 are mounted on the inverter 370 on the motor 80 side. As indicated by dashed lines (that is, hidden lines) in FIG. 4, the inverter elements 371 to 376, which are heating elements, and the relays 35, 36, 381, 382, and 383 are mounted on the surface of the power circuit board 301 on the side of the heat sink 601. It is A heat dissipation gel 18 is filled between the power circuit board 301 and the heat sink 601 . Thereby, heat can be efficiently dissipated (problem A).

The choke coil 33 and the capacitor 34, which are large components, are arranged on the opposite side of the power circuit board 301 from the heat sink 601. As shown in FIG. The arrangement and configuration of the large components will be described later after referring to the unit case 20 . Thus, the two power circuit boards 301 and 302 are provided with two systems of power circuits 310 and 320 for supplying power to the corresponding winding sets 810 and 820 of the motor 80, respectively. The configuration is simplified by using a common circuit board with the same specifications.

As shown in FIGS. 3 to 6, the two power circuit boards 301 and 302 are fixed to a pair of first arrangement portions 631 and 632. As shown in FIGS. In this embodiment, the power circuit boards 301 and 302 on which the inverter elements 371 to 376 are individually and directly mounted are fixed to the first arrangement portions 631 and 632 of the heat sink 601 without using the power module as in the comparative example. . Therefore, it is possible to maintain a high heat radiation effect from the inverter elements 371 to 376 without depending on vibration or the like caused by an external force (problem B). Moreover, since a power module is not used, the wiring pattern can be thickened and the loss can be reduced.

More specifically, the power circuit boards 301 and 302 are in contact with the bearing surfaces 68 of the support parts 67 projecting from the first arrangement parts 631 and 632 at a plurality of locations in the axial direction of the rotation axis O. is concluded by An anti-loosening adhesive may be applied to the outer periphery of the board screw 16 and the screw hole. For example, the support portions 67 are provided at positions corresponding to one end and the other end of the power circuit boards 301 and 302 in the axial direction of the rotation axis O, that is, at two locations in the axial direction. Thereby, the power circuit boards 301 and 302 are stably fixed to the heat sink 601 . Therefore, the heat generated by the inverter elements 371 to 376 mounted on the power circuit boards 301 and 302 is efficiently dissipated (problem B).

Control circuit board 400 is mounted with components of control circuits 410 and 420 that control driving of inverter 370 based on an input signal. In the first embodiment, one control circuit board 400 is provided with two systems of control circuits 410 and 420 that control driving of two systems of inverters 370 . Therefore, the number of parts can be reduced.

In FIG. 3, the microcomputer 43 of the first system control circuit 410, the driver IC 45, etc. are mounted on the right side of the center line of the control circuit board 400, and the microcomputer 43 of the second system control circuit 420, A driver IC 45 and the like are mounted. Components of the control circuits 410 and 420 of each system are arranged line-symmetrically. As a result, the conductor distance becomes equal in each system, and the balance is improved. As with the power circuit boards 301 and 302, the components of the control circuits 410 and 420 are mounted on the surface of the control circuit board 400 on the heat sink 601 side. Further, heat dissipation gel 18 is filled between the control circuit board 400 and the heat sink 601 .

An external signal is input to the microcomputer 43 from the control terminal 26 of the control system connector 24 through the external signal wiring 28 . Also, a rotation angle signal is input from a rotation angle sensor 53 mounted on the rotation angle sensor substrate 501 via a rotation angle signal wiring 54 . A communication line 44 connects the microcomputer 43 and the driver IC 45 . The driver IC 45 outputs drive signals to the inverter elements 371 to 376 of the power circuit boards 301 and 302 and the relays 35 , 36 , 381 , 382 and 383 through the drive signal wiring 46 .

As shown in FIGS. 3 to 6, one control circuit board 400 is fixed to one second placement portion 641 in the first embodiment. As with the power circuit boards 301 and 302, the control circuit board 400 is placed in contact with the seat surfaces 68 of the support parts 67 projecting from a plurality of positions in the axial direction of the rotation axis O in the second arrangement part 641. It is fastened with a screw 16 for use.

The unit case 20 is made of a resin material and has a bottomed cylindrical shape having a top plate portion 21 and an outer cylinder portion 22 . The unit case 20 covers the control unit 101 supported by the pillars 610 . For example, the lower end of the outer cylindrical portion 22 is inserted into and adhered to an annular groove formed in the upper surface 72 of the main body portion 71 of the partition wall portion 70 . A power connector 23 and a signal connector 24 are provided on the top plate portion 21 . As shown in FIG. 5, in the complete two-system configuration, a power connector 23 and a signal connector 24 are redundantly provided for each system. On the other hand, a pair of connectors 23 and 24 may be provided in a configuration of two drive systems in which a common battery or external signal is used for the two systems.

As shown in FIGS. 3 and 6, in the space between the cylindrical unit case 20 and the power circuit boards 301 and 302, a choke coil 33 and a capacitor, which are cylindrical electronic components defined as large components, are provided. 34 are arranged. The choke coil 33 and the capacitor 34 are arranged in the unit case 20 so that the axes of the cylinders of the choke coils 33 and the capacitors 34 are arranged along the axial direction of the rotation axis O.

Also, the choke coil 33 and the capacitor 34 of the same system are arranged in series along the axial direction of the rotation axis O. As shown in FIG. Furthermore, in the modification shown in FIG. 10, in a configuration in which each system includes a plurality of capacitors 34, one or more choke coils 33 and a plurality of capacitors 34 are arranged in series along the axial direction of the rotation axis O. there is That is, at least some of the plurality of large components are arranged in series along the axial direction of the rotation axis O.

Here, "arranged in series" means that other large parts are included within the projected range of the large part having the largest diameter. Each large part does not have to be arranged strictly on the same axis and may be eccentric within the projection range. As a result, compared to the comparative example in which the axis of the cylinder of the capacitor is orthogonal to the axial direction of the rotating shaft, it is possible to efficiently arrange large components in the clearance space within the unit case 20 (problem C). Therefore, even if a large-sized component with a larger size is used, it can be efficiently accommodated in the clearance space within the unit case 20 .

Furthermore, as shown in FIG. 6, the large parts 33 and 34 of the first system and the second system are arranged at point-symmetrical positions with respect to the rotation axis O. As shown in FIG. As a result, the large components 33 and 34 can be efficiently arranged in the clearance space where the distance in the radial direction of the rotation axis O is maximized (problem C).

In addition, the power circuit boards 301 and 302 on which the large-sized components 33 and 34 are mounted are fixed to the support portions 67 provided at a plurality of locations of the first placement portions 631 and 632 . The large-sized parts 33 and 34 of each system are arranged on the plane X in which the axis of the cylinder passes through the middle of the plurality of support portions 67 in the circumferential direction of the rotation axis O. As shown in FIG. As a result, the large components 33 and 34 are arranged in good balance on the stably fixed power circuit boards 301 and 302 (problem C).

(Second embodiment)
With reference to FIGS. 11 to 15, the configuration of the driving device according to the second embodiment will be described, in particular, the points of difference from the first embodiment. Figures 11-12 show the drive in an assembled state. 13 to 15 show the heat sink 602 alone, and FIG. 9 additionally shows the rotation angle sensor substrate 502. FIG. Here, the code of the heat sink in the second embodiment is "602", and the code of the control unit is "102".

The driving device 800 mainly includes a motor 80 , a heat sink 602 , a control unit 102 and a unit case 20 . The motor 80 is the same as that of the first embodiment except for the placement of the sensor magnet 882 . A unit case 20 is the same as in the first embodiment. The right side view of the power circuit board 301 in FIG. 11 conforms to FIG. 4 of the first embodiment.

As shown in FIGS. 13 to 15, the heat sink 602 of the second embodiment has a solid column portion 620 without recesses and a plate-like partition wall portion 70 . For example, the heat sink 602 is formed by joining two parts, a column portion 620 and a partition wall portion 70, by welding or brazing. That is, the motor-side end face 66 of the column portion 620 is joined to the upper surface 72 of the partition wall portion 70 . In particular, the outer peripheral portion of the motor-side end surface 66 is firmly fixed to the upper surface 72 of the partition wall portion 70 . This facilitates manufacturing. However, the column portion 620 and the partition wall portion 70 may be manufactured as an integrally molded product.

A pair of first placement portions 631 and 632 and a pair of second placement portions 641 and 642 that support the control unit 102 are provided on the four side surfaces of the column portion 620 so as to face radially outward. A pair of first arrangement portions 631 and 632 are the same as in the first embodiment. The pair of second placement portions 641 and 642 are orthogonal to the pair of first placement portions 631 and 632 and connect between the pair of first placement portions 631 and 632 . Similarly to the first arrangement portions 631 and 632, the second arrangement portions 641 and 642 have support portions to which the control circuit boards 401 and 402 are fixed at four locations near both ends in the axial direction and the circumferential direction of the rotation axis O. 67 is projected.

In the second embodiment, a sensor magnet 882 for rotation angle detection is attached to the outer circumference of the shaft 87 . The sensor magnet 882 and the rotation angle sensor substrate 502 on which the two rotation angle sensors 53 are mounted are arranged on the motor 80 side with respect to the partition wall 70 . This makes it possible to accommodate a configuration in which the column portion 620 does not have a concave portion and the rotation angle sensor substrate cannot be installed on the control unit 102 side of the partition wall portion 70 . As shown in FIG. 15, two rotation angle sensors 53 detect the rotation angle of the rotor 86 based on changes in the magnetic flux of the sensor magnets 882 . A rotation angle signal detected by each rotation angle sensor 53 is transmitted to the microcomputer 43 of each system via a rotation angle signal wiring 54 .

As described above, the control unit 102 has four circuit boards 301, 302, 401, 402 in the second embodiment. As shown in FIG. 12, the two power circuit boards 301 and 302 are fixed to a pair of first arrangement portions 631 and 632 as in the first embodiment. The two control circuit boards 401 and 402 are fixed to the pair of second arrangement portions 641 and 642 . The control circuit boards 401 and 402 are fastened with the board screws 16 while being in contact with the bearing surfaces 68 of the support parts 67 projecting from a plurality of positions in the axial direction of the rotation axis O in the respective second arrangement parts 641 and 642 . It is

The two control circuit boards 401 and 402 are provided with two systems of control circuits 410 and 420 for controlling the driving of the two systems of inverters 370 for each system. As shown in FIG. 11, the control circuit board 401 is mounted with the microcomputer 43 of the first system control circuit 410, the driver IC 45, and the like. A rotation angle signal is input to the microcomputer 43 from the rotation angle sensor 53 mounted on the rotation angle sensor substrate 502 through the rotation angle signal wiring 54 . A second system control circuit 420 is similarly provided on the control circuit board 402 . The configuration is simplified by using a common circuit board with the same specifications.

Other configurations of the heat sink 602 and the control unit 102 of the second embodiment are the same as those of the first embodiment. The functions and effects of the common configuration conform to the above description.

As described above, the second embodiment mainly differs from the first embodiment in the following points.
(1) The control unit 102 has a total of four circuit boards including two control circuit boards 401 and 402 .
(2) The solid column portion 620 has a pair of second placement portions 641 and 642 .
(3) The sensor magnet 882 and the rotation angle sensor substrate 502 are arranged on the motor 80 side with respect to the partition wall 70 .

However, these features are not necessarily implemented as a set, and items (2) and (3) may be combined alone in the first embodiment of the three-board configuration. For example, the solid column portion 620 may be used in the first embodiment, and the control circuit board 400 may be fixed to only one side of the pair of second placement portions 641 and 642 . Also, in the first embodiment, the configurations of the sensor magnet and the rotation angle sensor substrate can be replaced with those of the second embodiment.

(Other embodiments)
(a) The columnar portion of the heat sink does not have to be rectangular in cross section perpendicular to the axis of rotation, but may be parallelogram or trapezoidal. The shape of the partition and the fastening structure with the motor case are not limited to those of the above-described embodiment, and any shape and structure that provide the same effects as those of the above-described embodiment may be used.

(b) The drive device of the present invention may be applied to a single motor drive system, not limited to a dual system. In that case, one power circuit board may be fixed to only one of the pair of first placement portions. Alternatively, electronic components that constitute one system of power circuits may be separately mounted on two power circuit boards and fixed to the pair of first placement portions. In addition, in the case of a two-system configuration, instead of dividing the power circuits of the two systems into two power circuit boards for each system, the electronic components for the two systems are divided into two power circuit boards according to the type of electronic component. May be implemented.

(c) In a configuration in which two control circuits are provided on a single control circuit board, the components of each system are placed in line symmetry if an asymmetric arrangement is more advantageous for reasons of wiring and layout. It does not have to be.

(d) The method of fixing the power circuit board and the control circuit board to the pillars is not limited to fastening with screws, but crimping, pressure welding, or the like may also be used. Further, as described above, screw tightening and application of a screw locking adhesive may be used in combination.

(e) The arrangement of the large components is not limited to the above embodiment, and some or all of the large components may be arranged such that the axis of the cylinder is different from the axial direction of the rotating shaft. Also, multiple large components need not be arranged in series.

(f) The driving device 800 of the present invention is not limited to a steering assist motor for an electric power steering system, but can be used as a reaction force motor or steering motor for a steer-by-wire system, or any other motor driving device. good too.

As described above, the present invention is by no means limited to the above embodiments, and can be embodied in various forms without departing from the spirit of the present invention.

101, 102 (10) ... control unit,
20 unit case,
301, 302... Power circuit board (circuit board),
33 choke coil (large component),
34 ... Capacitor (large component),
370: Inverter, 371-376: Switching element (heat generating element),
400, 401, 402... control circuit board (circuit board),
601, 602 ... heat sinks,
610, 620 Pillars,
631, 632... First arrangement portion,
641, 642... second arrangement portion,
80 motor,
84... Stator, 86... Rotor, 87... Shaft.

Claims (5)

a motor (80) comprising a stator (84) and a rotor (86) rotating about a shaft (87) provided on an axis of rotation (O);
a control unit (101, 102) provided integrally with the motor on one side in the axial direction of the rotating shaft and controlling the driving of the motor;
A pair of first placement portions (631, 632) arranged on both sides of the rotation axis, and one or a pair of second placement portions (641, 642) connecting between the pair of first placement portions (641, 642) heat sinks (601, 602) facing radially outward and having pillars (610, 620) supporting the control unit;
a cylindrical unit case (20) covering the control unit supported by the column;
A drive device comprising:
The control unit has one or more circuit boards (301, 302, 400, 401, 402) fixed to the first placement portion or the second placement portion of the pillar,
If a choke coil (33) and a capacitor (34), which are columnar electronic parts that constitute the control unit, are defined as large parts,
The driving device, wherein the plurality of large-sized parts are arranged in the unit case with the axes of the cylinders along the axial direction of the rotating shaft. 2. The driving device according to claim 1, wherein at least some of the plurality of large-sized components are arranged in series along the axial direction of the rotating shaft. 3. The driving device according to claim 2, wherein one or more of the choke coils and one or more of the capacitors are arranged in series along the axial direction of the rotating shaft. The driving device according to any one of claims 1 to 3, wherein the plurality of large-sized parts are arranged at point-symmetrical positions with respect to the rotation axis. The circuit board on which the large component is mounted is fixed to support portions (67) provided at a plurality of locations of the first placement portion,
The driving device according to any one of claims 1 to 4, wherein the large-sized part has a columnar axis arranged on a plane passing through the middle of the plurality of support portions in the circumferential direction of the rotating shaft.

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