Drive device

Abstract

To provide a driving device in which a space for fastening a substrate is minimized.SOLUTION: In a driving device, a motor 80 and a control unit 10 are integrally configured. A motor frame 840 is provided in an end of the motor 80 at the side of the control unit 10 in an axial direction. A cover 50 includes a top plate 561 and an outer cylinder 562, at which one or more external connectors 57 and 58 are provided. Two or more substrates 31 and 32 are disposed in a multi-stage manner between the motor frame 840 and the top plate 561 from the first substrate 31 closest to the motor frame 840 to the second substrate 32 closest to the top plate 561, and electronic components constituting the control unit 10 are mounted thereon. An inter-substrate connection component 71 electrically connects the mutually adjacent substrates 31 and 32. A plurality of composite fastening members 401 performs fastening of the first substrate 31 and fastening of the second substrate 32 on the same axis regarding the fastening of the first substrate 31 and the second substrate 32 to the motor frame 840.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a drive device.

Background Art

[0002] Conventionally, a drive device in which a motor and a control unit are integrated is known.

[0003] For example, in the electromechanical device disclosed in Patent Document 1, two substrates (circuit carriers) are electrically connected by a plurality of connection elements. Each connection element is connected by a socket in the middle part of the two substrates.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the electromechanical device of Patent Document 1, the substrate (12) on the motor side and the substrate (14) on the cover side are electrically connected by a plurality of connection elements. However, a structure in which the two substrates are rigidly fixed to each other is not disclosed. If a location for rigidly fixing the substrates is not provided separately from the electrical connection portion between the substrates, there is a risk that the electrical connection portion may be disconnected due to stress such as vibration and heat and cold. However, providing a large number of fastening portions increases the diameter size of the drive device. For example, there is a problem that the mountability deteriorates in a drive device mounted on a vehicle.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a drive device with a minimum space for fastening substrates.

Means for Solving the Problems

[0007] The drive device according to the present invention is integrally configured with a motor (80) including a stator (860) and a rotor (865), and a control unit (10) provided on one axial side of the motor to drive and control the motor. This drive device includes a motor frame (840), a cover (50), two or more substrates (31, 32), one or more substrate connection components (63, 77, 78), and a plurality of composite fastening members (40 1 ).

[0008] The motor frame is provided at the end on the control unit side in the axial direction of the motor. The cover has a top plate portion (561) facing the motor frame and an outer cylinder portion (562) extending from the outer edge of the top plate portion toward the motor frame, and one or more external connectors (57, 58) are provided.

[0009] When N is an integer of 2 or more, two or more substrates are arranged in multiple stages between the motor frame and the top plate portion from the first substrate closest to the motor frame to the Nth substrate closest to the top plate portion, and electronic components constituting the control unit are mounted. One or more substrate connection components electrically connect between adjacent substrates. Regarding the fastening of a plurality of composite fastening members to at least a first substrate and a motor frame of a second substrate arranged in the second stage, the fastening of the first substrate and the fastening of the second substrate are performed on the same axis.

[0010] The composite fastening member has a column portion (410) of a predetermined height, a stud bolt (41) for fastening the first substrate to the motor frame, and is screwed into a female screw portion (414) formed on the upper end surface (412) of the column portion of the stud bolt, and includes an upper-stage bolt (42) for fastening the second substrate to the motor frame via the stud bolt. The size of the male screw portion (425) of the upper-stage bolt is set smaller than the size of the male screw portion (413) of the stud bolt.

[0011] In the present invention, by performing the fastening of the first substrate and the fastening of the second substrate on the same axis, the space for fastening the substrates can be minimized. Therefore, the mounting area of the electronic components can be ensured without increasing the diameter size of the drive device.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

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Figure 8

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Figure 10

Figure 11

Figure 12

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Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0013] Hereinafter, a plurality of embodiments of the drive device according to the present invention will be described with reference to the drawings. In the plurality of embodiments, substantially the same configurations are denoted by the same reference numerals and the description thereof is omitted. The "present embodiment" includes the first to fourth embodiments. The drive device of the present embodiment is applied, for example, as a steering assist motor of an electric power steering device, and is integrally configured with a motor and a control unit that drives and controls the motor. The third and fourth embodiments correspond to reference embodiments.

[0014] [Configuration of Electric Power Steering Device] Referring to FIG. 1, the schematic configuration of the electric power steering device 99 will be described. Although FIG. 1 illustrates a rack assist type electric power steering device, the drive device 800 of the present embodiment can be similarly applied to a column assist type electric power steering device. The steering system 90 including the electric power steering device 99 includes a steering wheel 91, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, and the electric power steering device 99, etc.

[0015] A torque sensor 93 for detecting the steering torque is provided on the steering shaft 92 to which the steering wheel 91 is connected. A pinion gear 96 that meshes with the rack shaft 97 is provided at the tip of the steering shaft 92. When the driver rotates the steering wheel 91, the rotational motion of the steering shaft 92 is converted into a 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 at an angle corresponding to the displacement amount of the rack shaft 97.

[0016] The electric power steering device 99 includes a drive device 800 in which a motor 80 and a control unit 10 are integrally configured, and a reduction gear 89 that reduces the rotation of the motor 80 and transmits it to the rack shaft 97, etc. The motor 80 is a two-system three-phase brushless motor having two sets of three-phase windings. The control unit 10 can supply power to the two sets of three-phase windings by two-system inverter circuits. In particular, in the present embodiment, a "fully two-system" configuration in which power and signals are input and output for each system is assumed. By supplying the three-phase AC power converted from DC power by the inverter circuit of the control unit 10, the motor 80 outputs a steering assist torque.

[0017] The power supply connector 57 of the control unit 10 is supplied with DC power from the vehicle power supply 905, and communication signals with the vehicle communication network ("CAN" in the figure) 906 are input and output. The sensor signal detected by the torque sensor 93 is input to the signal connector 58 via the harness 94. The power supply connector 57 and the signal connector 58 correspond to "one or more external connectors" to which power and signals are input from the outside, and are distinguished from the plug connectors described later provided inside the control unit 10.

[0018] [Configuration of the drive device] Referring to FIGS. 2 and 3, the overall configuration of the drive device 800 will be described. The direction parallel to the rotation axis O of the motor 80 shown in FIG. 2 is defined as the "axial direction", and the view from the upper side of FIG. 2 in the axial direction is referred to as a plan view. The control unit 10 is provided on one side in the axial direction of the motor 80. That is, the drive device 800 has a so-called "mechatronic" configuration.

[0019] The motor 80 includes a motor case 830, a motor frame 840, a stator 860, a rotor 865, etc. The motor case 830 is formed in a substantially bottomed cylindrical shape composed of a bottom portion 831 and a cylindrical portion 832, and the control unit 10 is provided on the opening side. A thin groove forming wall 834 is formed at the opening side end of the cylindrical portion 832 via a stepped portion 833.

[0020] The stator 860 is fixed inside the cylindrical portion 832 of the motor case 830, and a three-phase motor winding 880 is wound around it. By controlling the energization of the motor winding 880 by the control unit 10, a rotating magnetic field is formed in the stator 860. The rotor 865 is provided inside the stator 860 and a shaft 870 is fixed at the center. The shaft 870 is rotatably supported by a front bearing 871 held by the bottom portion 831 of the motor case 830 and a rear bearing 872 held by the motor frame 840.

[0021] The rotor 865 has a plurality of permanent magnets 867 provided on the outer periphery of the rotor core 866. The rotor 865 rotates about the shaft 870 due to the rotating magnetic field formed in the stator 860. A sensor magnet 875 for detecting the rotation angle is provided at the end of the shaft 870 on the control unit 10 side.

[0022] The motor frame 840 is provided at the end of the motor 80 on the control unit 10 side in the axial direction. The motor frame 840 is formed of an aluminum alloy or the like and has a frame portion 841 and a flange portion 842. The frame portion 841 is press-fitted inside the motor case 830. The flange portion 842 formed on the outer periphery of the frame portion 841 abuts against the stepped portion 833 of the motor case 830. A seal groove 843 filled with an adhesive is formed in the annular space partitioned by the outer wall of the frame portion 841, the surface of the flange portion 842 on the control unit 10 side, and the inner wall of the groove forming wall 834 of the motor case 830. The motor frame 840 also functions as a heat sink for dissipating the heat generated when the control unit 10 is energized.

[0023] The cover 50 is formed of a resin material such as PBT and has a top plate portion 561 facing the motor frame 840 and an outer cylinder portion 562 extending from the outer edge of the top plate portion 561 toward the motor frame 840. A convex portion 563 protruding in the axial direction is formed in an annular shape at the tip of the outer cylinder portion 562. By inserting the convex portion 563 into the seal groove 843, the outer cylinder portion 562 is fixed to the motor 80 or the motor frame 840.

[0024] The cover 50 is provided with an external connector including a power supply connector 57 and a signal connector 58. For example, the external connectors 57 and 58 are provided so that the frontage faces the side opposite to the motor 80 from the top plate portion 561. FIG. 3 shows an arrangement example of the external connectors 57 and 58. Note that FIG. 3 is a view taken in the direction of arrow III in FIG. 2, and is illustrated so as to match the scale of FIGS. 5, 6, and 7 which are plan views of each component, rather than matching the scale of FIG. 2.

[0025] The external connectors 57 and 58 may be provided redundantly in two sets as shown in FIG. 3, or may be provided in one set in other arrangement examples. The configuration in which two sets of external connectors 57 and 58 are provided is mainly adopted in a drive device of a "fully two-system" type in which two systems of inverter circuits are connected to individual power supplies and various signals are input and output redundantly. In FIG. 3, the reference numerals of the two-system external connectors are not distinguished, and the same "57" and "58" are attached. Also, the power supply terminals, communication terminals, and signal terminals in each external connector are not distinguished, and are uniformly referred to as "connector terminals 65".

[0026] Subsequently, the configurations of the control units of the respective embodiments will be described in order. The reference numerals of the control units of the first and second embodiments are assigned the embodiment number in the third digit following "10". In the first embodiment and the second embodiment, the configuration of the "inter-board connection component" that electrically connects between two boards is different.

[0027] (First Embodiment) With reference to FIGS. 4 to 8, the configuration of the control unit 101 of the first embodiment will be described. FIG. 4 is a schematic cross-sectional view showing each element at a position where it is easy to view for convenience of explanation, and is not a view corresponding to a specific cross-sectional line in FIG. 3 and the like. FIGS. 5, 6, and 7 are respectively plan views of the motor frame 840, the motor-side board 31, and the connector-side board 32. FIG. 8 shows the configuration of the "composite fastening member" that fastens the two boards 31 and 32 to the motor frame 840.

[0028] In the first embodiment, two boards 31 and 32 on which electronic components constituting the control unit 101 are mounted are arranged in two stages between the motor frame 840 and the top plate portion 561 of the cover 50. That is, in the "N boards" generalized with N being an integer of 2 or more in the column of other embodiments, the first embodiment has a configuration of "N = 2". The motor-side board 31 corresponds to the "first board" closest to the motor frame 840. The connector-side board 32 arranged in the second stage is the "second board", and in this case, also corresponds to the "Nth board" closest to the top plate portion 561.

[0029] On the motor-side substrate 31, three-phase two-system motor terminals 68 connected to the motor winding 880 are connected. As shown in FIG. 6, a plurality of motor terminal holes 318 through which the respective three motor terminals 68 are inserted are formed at diagonal positions across the rotation axis O on the motor-side substrate 31.

[0030] On the connector-side substrate 32, various connector terminals 65 connected to the external connectors 57 and 58 are connected. As shown in FIG. 7, a plurality of connector terminal holes 325 through which the connector terminals 65 are inserted are formed in the connector-side substrate 32.

[0031] Note that the "connector" in the name of the "connector-side substrate 32" means the external connectors 57 and 58. Also, although the connector-side substrate 32 of the first embodiment is arranged on the side of the external connectors 57 and 58 even in terms of spatial position, originally, it is a name meaning a substrate wired on the side of the external connectors 57 and 58 in electrical connection. Therefore, it can be interpreted in the same way even in an arrangement where the external connectors protrude from the side surface of the outer cylinder portion 562 as described in other embodiments.

[0032] As shown in FIG. 5, in this example, four boss portions 846 are provided on the motor frame 840. Female screw portions 848 are formed on the seating surfaces 847 of the respective boss portions 846. As shown in FIG. 6, four fastening holes 314 are formed at the same positions as the female screw portions 848 of the boss portions 846 on the motor-side substrate 31. As shown in FIG. 7, four fastening holes 324 are also formed at the same positions as the female screw portions 848 of the boss portions 846 on the connector-side substrate 32. That is, the fastening holes 314 and 324 of the two substrates 31 and 32 and the female screw portion 848 of the motor frame 840 are formed on the same axis.

[0033] The motor-side substrate 31 is placed on the seating surfaces 847 of four bosses 846 provided on the motor frame 840, and is fastened to the motor frame 840 through the fastening holes 314 by stud bolts 41. The connector-side substrate 32 is placed on the upper end surface of the stud bolt 41, and is fastened to the stud bolt 41 through the fastening holes 324 by the upper bolts 42. That is, the connector-side substrate 32 is fastened to the motor frame 840 via the stud bolt 41. Therefore, the motor-side substrate 31 and the connector-side substrate 32 are rigidly fixed to each other.

[0034] In this configuration, the stud bolt 41 and the upper bolt 42 constitute a "composite fastening member 401" that performs the fastening of the motor-side substrate 31 and the fastening of the connector-side substrate 32 to the motor frame 840 on the same axis. Details of the composite fastening member 401 will be described later with reference to FIG. 8.

[0035] Supplementary with reference to FIGS. 5 to 7, in the motor-side substrate 31 and the connector-side substrate 32, fastening holes are not formed except for the four fastening holes 314 and 324 used for fastening the composite fastening member 401. In other words, the composite fastening member 401 is used at all fastening locations of the motor-side substrate 31 and the connector-side substrate 32.

[0036] The plug connectors 77 and 78 as "inter-substrate connection parts" electrically connect between the motor-side substrate 31 and the connector-side substrate 32, and for example, commercially available board-to-board (BtoB) connectors are used. As shown in FIGS. 4 and 6, the electrical connection may be shared by two parts, the power supply plug connector 77 and the signal plug connector 78.

[0037] The lower parts 771 and 781 of the plug connectors 77 and 78 are surface-mounted on the upper surface of the motor-side substrate 31, and the upper parts 772 and 782 are attached to the lower surface of the connector-side substrate 32. The lower parts 771 and 781 and the upper parts 772 and 782 are electrically connected by the fitting of the male terminals and the female terminals. The height at the time of connection can be adjusted within a predetermined range. Therefore, even if the distance between the substrates 31 and 32 changes slightly, it is possible to flexibly respond.

[0038] Referring to FIG. 8, the detailed configuration of the composite fastening member 401 of the first embodiment will be described. The composite fastening member 401 is composed of a stud bolt 41 having a column portion 410 of a predetermined height and an upper bolt 42. The stud bolt 41 has a male screw portion 413 protruding from the lower end surface 411 of the column portion 410, and a female screw portion 414 formed on the upper end surface 412. The lower end surface 411 of the column portion 410 abuts against the periphery of the fastening hole 314 of the motor-side substrate 31 via a wave washer 417 and a washer 418.

[0039] The upper bolt 42 is a general-purpose screw such as a pan head screw having a male screw portion 425 and a head portion 426. The male screw portion 425 is screwed into the female screw portion 414 formed on the upper end surface 412 of the column portion 410 of the stud bolt 41. The head portion 426 abuts against the periphery of the fastening hole 324 of the connector-side substrate 32 via a wave washer 427 and a washer 428.

[0040] Here, the size of the male screw portion 425 of the upper bolt 42 is set smaller than the size of the male screw portion 413 of the stud bolt 41. For example, according to the JIS standard, the male screw portion 425 of the upper bolt 42 is M3, and the male screw portion 413 of the stud bolt 41 is M4. By setting it in this way, an appropriate fastening force can be obtained and the loosening of the screw can be prevented.

[0041] A female screw portion 848 is formed on the seating surface 847 of the boss portion 846 of the motor frame 840. When assembling the drive device 800, first, the male screw portion 413 of the stud bolt 41 is screwed into the female screw portion 848 of the motor frame 840 through the fastening hole 314 of the motor-side substrate 31, so that the motor-side substrate 31 is fastened to the motor frame 840. Next, the upper bolt 42 is screwed into the female screw portion 414 of the stud bolt 41 through the fastening hole 324 of the connector-side substrate 32, so that the connector-side substrate 32 is fastened to the motor frame 840 via the stud bolt 41.

[0042] The effects of the first embodiment will be described. Items [1] to [3] are also common to the second to fourth embodiments. Item [4] is also common to the second embodiment.

[0043] [1] In the prior art of Patent Document 1 (International Publication No. 2020 / 120178), a structure in which two substrates on the motor side and the cover side are rigidly fixed is not disclosed, and there is a risk that the electrical connection portion may be disconnected due to stress such as vibration and heat. On the other hand, in the drive device 800 of the present embodiment, the substrates 31 and 32 are fastened to the motor frame 840, so that they are rigidly fixed to each other. Thereby, since external stress due to vibration, cold and heat, etc. is prevented from acting on the electrical connection portion, the durability of the electrical connection portion can be ensured.

[0044] [2] The effect of using the composite fastening member 401 for fastening the two substrates 31 and 32 will be described in comparison with the comparative example. In the control unit 109 of the comparative example shown in FIG. 15, the motor-side substrate 31 is fastened to the motor frame 840 alone by the general-purpose screw 4. The connector-side substrate 329 formed to be slightly larger than the motor-side substrate 31 is fastened to the motor frame 840 by the long screw 49 via the collar 48 interposed between the motor frame 840 and the connector-side substrate 329. When the motor-side substrate 31 and the connector-side substrate 329 are each fastened at four locations, a total of eight fastening portions are required. Even if a notch for escaping the collar 48 is provided in a part of the circumferential direction of the motor-side substrate 31, the diameter size of the control unit 109 increases in order to secure the mounting area of the electronic components.

[0045] In a drive device in which the motor and the control unit are coaxially and integrally configured, even if the diameter size of the motor part is the same, the diameter size of the entire drive device is determined by the diameter size of the control unit part. Therefore, the mountability of the drive device deteriorates due to an increase in the number of fastening points of the control unit 109. In addition, the number of parts also increases by using the collar 48 for fastening the connector-side substrate 329.

[0046] In contrast, in the first embodiment, by fastening the motor-side substrate 31 and the connector-side substrate 32 coaxially with the composite fastening member 401, the space for fastening the substrates 31 and 32 can be minimized. Therefore, without increasing the diameter size of the drive device 800, the mounting area for electronic components can be secured. As a result, the mountability is improved due to miniaturization and weight reduction, which also leads to cost reduction.

[0047] [3] In the first embodiment, the composite fastening member 401 is used at all fastening locations of the motor-side substrate 31 and the connector-side substrate 32. That is, there are no fastening locations other than those where the composite fastening member 401 is used. Therefore, the mounting area for electronic components can be secured to the maximum extent, and the effect of [2] is particularly effectively exerted.

[0048] [4] The composite fastening member 401 of the first embodiment is composed of a stud bolt 41 and an upper bolt 42. In this structure, it is advantageous for ensuring the axial force that the lower end surface 411 of the column portion 410 presses the motor-side substrate 31. Also, since the screw chips of the upper bolt 42 do not fall around, the quality is improved. Furthermore, cost reduction is possible by using a general-purpose screw for the upper bolt 42.

[0049] [5] The inter-board connection components of the first embodiment are composed of plug connectors 77 and 78 whose height can be adjusted during connection. Therefore, the distance between the motor-side substrate 31 and the connector-side substrate 32 can be flexibly adjusted according to the height of the column portion 410 of the easily procured stud bolt 41.

[0050] (Second Embodiment) Next, referring to FIGS. 9 and 10, the second embodiment will be described. In the control unit 102 of the second embodiment, the motor-side substrate 31 and the connector-side substrate 32 are electrically connected by a plurality of inter-board terminals 63 as "inter-board connection components". Both ends of the plurality of inter-board terminals 63 are electrically connected to the motor-side substrate 31 and the connector-side substrate 32 in a press-fit manner. As shown by the dashed line, the intermediate portions of the plurality of inter-board terminals 63 may be bundled by a resin terminal binder 630.

[0051] FIG. 10 shows an example of a press-fit connection shape. A press-fit portion 638 formed at an end of the inter-board terminal 63 so as to be elastically deformable is press-fitted into the inter-board terminal hole 316 of the motor-side board 31, thereby achieving a press-fit connection. The inter-board terminal hole 316 is provided in a conductive portion 38 such as a via hole. The conductive portion 38 is electrically connected to electronic components and other terminals via a conductive pattern, a bus bar, etc. not shown in the figure. The press-fit connection shape is not limited to the ring shape in FIG. 10, and any elastically deformable shape may be used.

[0052] In the second embodiment, by using the press-fit type inter-board terminal 63, the distance between the two boards 31 and 32 can be flexibly adjusted according to the height of the column portion 410 of the easily procured stud bolt 41. The inter-board terminal 63 is not necessarily press-fit connected at both ends. One end may be press-fit connected and the other end may be electrically connected to the board by soldering or the like. The same operational effects can be obtained by press-fit connecting at least one end.

[0053] (Third and Fourth Embodiments) Next, referring to FIGS. 11 and 12, the third and fourth embodiments related to variations of the composite fastening member will be described. The composite fastening member 403 of the third embodiment shown in FIG. 11 is composed of a stepped bolt 45. The stepped bolt 45 has a male screw portion 453 protruding from the lower end surface 451 of the step portion that abuts around the fastening hole 314 of the motor-side board 31. The head 456 abuts around the fastening hole 324 of the connector-side board 32 via a wave washer 457 and a washer 458.

[0054] In the third embodiment, after the motor-side substrate 31 and the connector-side substrate 32 are electrically connected by the plug connectors 77 and 78 and the plurality of inter-board terminals 63, the two substrates 31 and 32 are fastened together to the motor frame 840 by the stepped bolt 45. By rotating the head 456, the axial force is transmitted to the connector-side substrate 32 via the wave washer 457 and the washer 458, and is also transmitted from the lower end surface 451 of the stepped portion to the motor-side substrate 31. Note that, at the stage when the motor-side substrate 31 is placed on the motor frame 840, a temporary fixing pin may be inserted into the female screw portion 848 of the motor frame 840 through the fastening hole 314 as required for work.

[0055] The composite fastening member 404 of the fourth embodiment shown in FIG. 12 is composed of a stud bolt 46 of a double male screw type having a column portion 460 of a predetermined height and a nut 47. The hexagon shown by the two-dot chain line in the middle of the column portion 460 has a hexagonal cross section, indicating that it is possible to perform a rotating operation with a tool. In the double male screw type stud bolt 46, a lower male screw portion 463 projects from the lower end surface 461 of the column portion 460, and an upper male screw portion 464 projects from the upper end surface 462. The cross-sectional shape of the column portion 460 is not limited to a hexagon, and for example, a two-sided width portion may be formed on the outer periphery.

[0056] When assembling the drive device 800, first, the motor-side substrate 31 is fastened to the motor frame 840 by screwing the lower male screw portion 463 of the double male screw type stud bolt 46 through the fastening hole 314 of the motor-side substrate 31 into the female screw portion 848 of the motor frame 840. Next, the nut 47 is screwed onto the upper male screw portion 464 of the double male screw type stud bolt 46 through the fastening hole 324 of the connector-side substrate 32, so that the connector-side substrate 32 is fastened to the motor frame 840 via the double male screw type stud bolt 46.

[0057] Similar to the first embodiment, in the third and fourth embodiments as well, the fastening of the motor-side substrate 31 and the fastening of the connector-side substrate 32 to the motor frame 840 are performed on the same axis. Thereby, the space for fastening the substrates 31 and 32 can be minimized, and the mounting area of the electronic components on the substrates 31 and 32 can be ensured without increasing the diameter size of the drive device 800.

[0058] (Reference configuration) Figures 13 and 14 show a control unit 100 with a single-board configuration as a reference configuration. For example, in a drive device of one system or "two drive systems", since the circuit scale of the control unit 100 is small, all electronic components can be mounted on a single single-board 3. Note that "two drive systems" refers to a configuration in which two inverter circuits are connected in parallel to a common power supply and various signals are shared between the systems. The single-board 3 is fastened to the motor frame 840 with a general-purpose screw 4.

[0059] Therefore, when manufacturing two types of drive devices with a two-board configuration and a single-board configuration, it is preferable to make the fastening positions of the boards common. The plan view of the motor frame 840 to which the single-board 3 is fastened is common with FIG. 5. In the plan view of the single-board 3 shown in FIG. 14, the fastening holes 314 and the motor terminal holes 318 are common with the fastening holes 314 and the motor terminal holes 318 in FIG. 6. Also, in one system, since there is a set of external connectors 57 and 58, the number of connector terminal holes 325 is half the number of connector terminal holes 325 in FIG. 7.

[0060] In this way, by making the board fastening positions of the two types of drive devices with a two-board configuration and a single-board configuration common, it is effective particularly when sharing the fastening equipment on the same manufacturing line. It is also effective when sharing the component inspection equipment for the boards.

[0061] (Other embodiments) (a) Between the motor frame 840 and the top plate portion 561 of the cover 50, three or more boards may be arranged in multiple stages. Generalizing with N as an integer of 2 or more, in the present invention, N boards may be arranged in multiple stages from the first board closest to the motor frame 840 to the Nth board closest to the top plate portion 561. Even when three or more boards are provided, it is a requirement of the present invention that at least the first board and the second board are fastened on the same axis using a plurality of composite fastening members.

[0062] For substrates above the third substrate, they may be fastened to the motor frame 840 alone without using composite fastening members. Alternatively, stud bolts conforming to the first embodiment may be stacked in two layers between the first substrate and the second substrate, and between the second substrate and the third substrate, and the three substrates may be fastened on the same axis. In that case, the "upper bolts" for fastening the second substrate are construed as being composed of stud bolts.

[0063] Also, when N substrates are provided, the substrate connection components electrically connect between adjacent substrates. That is, substrate connection components are provided between the first substrate and the second substrate, between the second substrate and the third substrate... between the (N - 1)th substrate and the Nth substrate. In that case, the same type of substrate connection components may be used, or different types may be used in combination.

[0064] (b) In the first embodiment, the composite fastening member 401 is used at all fastening locations of the motor-side substrate 31 and the connector-side substrate 32. Not limited to this configuration, for example, the composite fastening member 401 may be used at all fastening locations (for example, two locations) of the connector-side substrate 32, and the motor-side substrate 31 may be fastened to the motor frame 840 alone by general-purpose screws at other locations (for example, two locations). Alternatively, the composite fastening member 401 may be used only at some fastening locations for both the motor-side substrate 31 and the connector-side substrate 32, and the remaining locations may be fastened to the motor frame 840 alone respectively.

[0065] (c) The number, size, shape, etc. of the external connectors provided on the cover 50 are not limited to those exemplified in the above embodiment. The number of external connectors may be one or more. Also, the external connectors may have a "side-out" specification that protrudes in a direction perpendicular to the motor axis from the side surface of the outer cylinder portion 562, instead of an "up-out" specification that protrudes in the motor axis direction from the top plate portion 561 of the cover 50.

[0066] (d) The drive device 800 of the present invention may be used not only as a steering assist motor of an electric power steering device, but also as a reaction force motor or a steering motor of a steer-by-wire system, or a drive device for any other motor.

[0067] As described above, the present invention is not limited to the above embodiments, and can be implemented in various forms without departing from the spirit thereof.

Explanation of Reference Numerals

[0068] 10(101 - 102) ··· Control unit 31 ··· Motor-side substrate (first substrate), 32 ··· Connector-side substrate (second substrate) 401, 403, 404 ··· Composite fastening members 50 ··· Cover, 561 ··· Top plate portion, 562 ··· Outer cylinder portion 57, 58 ··· External connectors 63 ··· Inter-substrate terminal (inter-substrate connection component) 77, 78 ··· Plug connectors (inter-substrate connection components) 80 ··· Motor, 840 ··· Motor frame 860 ··· Stator, 865 ··· Rotor

Claims

1. A drive device in which a motor (80) including a stator (860) and a rotor (865) and a control unit (10) provided on one axial side of the motor and configured to drive and control the motor are integrally formed, a motor frame (840) provided at an end portion on the control unit side in the axial direction of the motor, a cover (50) having a top plate portion (561) facing the motor frame and an outer cylinder portion (562) extending from the outer edge of the top plate portion toward the motor frame, and having one or more external connectors (57, 58), when N is an integer of 2 or more, two or more substrates (31, 32) on which electronic components constituting the control unit are mounted, arranged in multiple stages between the motor frame and the top plate portion from the first substrate closest to the motor frame to the Nth substrate closest to the top plate portion, one or more inter-substrate connection components (63, 77, 78) for electrically connecting between the adjacent substrates, a plurality of composite fastening members (401) for fastening at least the first substrate and the second substrate arranged in the second stage to the motor frame, with the fastening of the first substrate and the fastening of the second substrate being performed on the same axis, comprising, the composite fastening member, has a column portion (410) of a predetermined height, a stud bolt (41) for fastening the first substrate to the motor frame, a top bolt (42) that is screwed into a female screw portion (414) formed on an upper end surface (412) of the column portion of the stud bolt and fastens the second substrate to the motor frame via the stud bolt, is composed of, a drive device in which the size of the male screw portion (425) of the top bolt is set smaller than the size of the male screw portion (413) of the stud bolt.

2. The drive device according to claim 1, wherein the composite fastening member is used at all fastening locations of the second substrate.

3. The drive device according to claim 1 or 2, wherein the inter-substrate connection component is composed of plug connectors (77, 78) whose height can be adjusted during connection.

4. The drive device according to claim 1 or 2, wherein the inter-substrate connection component is composed of a plurality of inter-substrate terminals (63) at least one end of which is electrically connected to the substrate by a press-fit method.

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