JP2009277726A - Laminated circuit board, motor controller and steering device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a foreign matter from being generated from a laminated circuit board. <P>SOLUTION: A power substrate 78 includes a substrate body 301 composed by laminating first, third, fifth and seventh layers 311, 313, 315 and 317 as insulating layers and second, fourth and sixth layers 312, 314 and 316 as layers including conductors. The outer side face 301c of the substrate body 301 is covered with a cover member 304. Thus, a material configuring the insulating layers is prevented from dispersing as dust (foreign matter) from the outer side face 301c of the substrate body 301. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laminated circuit board, a motor control device, and a vehicle steering device.

Usually, a laminated circuit board is formed by laminating a conductor layer and an insulating layer (see, for example, Patent Documents 1 to 4).
JP 2002-9435 A JP-A-8-78849 JP-A-5-243743 JP 2006-237115 A

  The laminated circuit board is formed by punching a manufacturing intermediate in which a conductor layer and an insulating layer are laminated. The insulating layer is formed using, for example, a synthetic resin containing ceramic or the like. For this reason, there is a possibility that dust (foreign matter) such as ceramic powder may be generated on the cut surface cut by punching. Such dust may cause bonding failure when bonding electronic components to the laminated circuit board. In particular, in a control board that controls an electric motor of an electric power steering apparatus, such dust may enter a motor bearing or the like and promote wear of the bearing.

  The present invention has been made under such a background, and an object of the present invention is to provide a laminated circuit board, a motor control device, and a vehicle steering device that can prevent foreign matters from being produced from the laminated circuit board.

  In order to achieve the above object, the present invention comprises a layer (312, 314, 316) including conductors (312a, 312c, 314a, 316a, 316b, 316d) and an insulating layer (311, 313, 315, 317). The substrate body includes a front surface (301a) and a back surface (301b) facing the stacking direction (D), and a side surface (301c). The side surface is a laminated circuit board (78) covered with the covering member (claim 1).

For example, a laminated circuit board is formed by stamping a manufacturing intermediate in which a layer including a conductor and an insulating layer are laminated. The insulating layer is formed using, for example, a synthetic resin containing ceramic or the like. Moreover, the layer including the conductor and the insulating layer are exposed on the side surface of the multilayer circuit board by punching.
According to the present invention, since the side surface of the substrate main body is covered with the covering member, for example, the material constituting the insulating layer can be prevented from being scattered as dust (foreign matter) from this side surface. Thereby, it can prevent that a foreign material adheres to the surface etc. of a board | substrate body, and can prevent the joining defect at the time of joining an electronic component to a laminated circuit board reliably.

Moreover, in this invention, the said insulating layer may contain a base material and a heat conductive material whose heat conductivity is higher than this base material (Claim 2). In this case, the thermal conductivity of the insulating layer can be increased, and the heat dissipation of the substrate body can be further increased.
In the present invention, the substrate body is provided with a via hole (308), and the surface of the substrate body includes a bonding portion (326) for bonding by wire bonding, and the bonding portion is related to the stacking direction. In some cases, the via holes are disposed away from the via holes. In this case, the portion of the substrate body where the via hole is formed has irregularities on the surface of the substrate body as the via hole is formed. On the other hand, since the operation for forming the via hole is not performed in the portion where the via hole is not formed, the surface of the substrate body is not uneven. Thus, since the joint portion is provided in the smooth portion of the surface of the substrate body where the irregularities are not generated, the joint portion and the bonding wire bonded to the joint portion can be reliably bonded, It is possible to sufficiently secure the bonding strength between the two. In addition, since it is not necessary to form a joint using another component such as a bonding pad, the cost is low.

  In the present invention, the multilayer circuit board includes a metal base (302) bonded to the back surface of the substrate body and positioning holes (321a, 321b) formed in the metal base. In some cases, positioning members (318, 319) formed on the board installation member (77a) on which the metal base is installed can be fitted (claim 4). In this case, the positioning accuracy of the laminated circuit board with respect to the board installation member can be further increased.

  Further, the present invention may include the above-described multilayer circuit board and a motor drive circuit (82) including a motor drive element (83) mounted on the board body of the multilayer circuit board (Claim 5). . In this case, since dust (foreign matter) is prevented from being generated from the laminated circuit board, it is possible to prevent such foreign matter from entering the motor bearing or the like and promoting wear of the motor bearing.

  In the present invention, there may be provided a motor control device (78) and an electric motor (18) that is driven by the motor control device and applies a steering force to the steering mechanism (4). In this case, it is possible to realize a vehicle steering apparatus in which the bonding failure of the electronic components mounted on the multilayer circuit board is reliably prevented and the wear of the motor bearings and the like is suppressed.

  In the above description, numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering apparatus 1 as a vehicle steering apparatus according to an embodiment of the present invention.
Referring to FIG. 1, an electric power steering apparatus 1 assists steering by a steering wheel 2 as a steering member, a steering mechanism 4 that steers the steered wheels 3 in conjunction with the rotation of the steering wheel 2, and a driver. A steering assist mechanism 5 is provided. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

In the present embodiment, the steering assist mechanism 5 will be described based on an example in which an assist force (steering assist force) is applied to the steering shaft 6. However, the present invention is applied to the pinion shaft described later. The present invention can be applied to a structure for giving or an assisting mechanism 5 for giving assist force to a rack shaft, which will be described later.
The steering shaft 6 extends linearly. Steering shaft 6 includes an input shaft 8 connected to steering wheel 2 and an output shaft 9 connected to intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be relatively rotatable on the same axis. That is, when a steering torque greater than a certain value is input to the steering wheel 2, the input shaft 8 and the output shaft 9 rotate in the same direction while rotating relative to each other.

  A torque sensor 11 disposed around the steering shaft 6 detects the steering torque input to the steering wheel 2 based on the relative rotational displacement amounts of the input shaft 8 and the output shaft 9. The torque detection result of the torque sensor 11 is input to an ECU 12 (Electronic Control Unit) as a control device. Further, the vehicle speed detection result from the vehicle speed sensor 90 is input to the ECU 12. The intermediate shaft 7 connects the steering shaft 6 and the steering mechanism 4.

The steering mechanism 4 includes a rack and pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steered shaft. A steered wheel 3 is connected to each end of the rack shaft 14 via a tie rod 15 and a knuckle arm (not shown).
The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in conjunction with the steering of the steering wheel 2. A pinion 16 is connected to the tip of the pinion shaft 13 (the lower end in FIG. 1).

  The rack shaft 14 extends linearly along the left-right direction of the automobile. A rack 17 that meshes with the pinion 16 is formed in the middle of the rack shaft 14 in the axial direction. By the pinion 16 and the rack 17, the rotation of the pinion shaft 13 is converted into the axial movement of the rack shaft 14. The steered wheel 3 can be steered by moving the rack shaft 14 in the axial direction.

When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into an axial movement of the rack shaft 14 by the pinion 16 and the rack 17. Thereby, the steered wheel 3 is steered.
The steering assist mechanism 5 includes a steering assist electric motor 18 and a speed reduction mechanism 19 as a transmission mechanism for transmitting the output torque of the electric motor 18 to the steering mechanism 4. As the speed reduction mechanism 19, for example, a staggered shaft gear mechanism such as a worm gear mechanism, a parallel shaft gear mechanism, or the like can be used. In the present embodiment, a worm gear mechanism is used as the speed reduction mechanism 19. That is, the speed reduction mechanism 19 includes a worm shaft 20 as a drive gear (drive-side member of the transmission mechanism) and a worm wheel 21 as a driven gear (driven-side member of the transmission mechanism) that meshes with the worm shaft 20. The speed reduction mechanism 19 is accommodated in a gear housing 22 as a transmission housing.

The worm shaft 20 is connected to a rotating shaft (not shown) of the electric motor 18 through a joint (not shown). The worm shaft 20 is rotationally driven by the electric motor 18. The worm wheel 21 is connected to the steering shaft 6 so as to be able to rotate together. The worm wheel 21 is rotationally driven by the worm shaft 20.
When the electric motor 18 rotationally drives the worm shaft 20, the worm wheel 21 is rotationally driven by the worm shaft 20, and the worm wheel 21 and the steering shaft 6 rotate together. The rotation of the steering shaft 6 is transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into the axial movement of the rack shaft 14. Thereby, the steered wheel 3 is steered. That is, the steered wheels 3 are steered by rotating the worm shaft 20 by the electric motor 18.

  The electric motor 18 is controlled by the ECU 12. The ECU 12 controls the electric motor 18 based on the torque detection result from the torque sensor 11, the vehicle speed detection result from the vehicle speed sensor 90, and the like. Specifically, the ECU 12 determines a target assist amount using a map in which the relationship between the torque and the target assist amount is stored for each vehicle speed, and controls the assist force generated by the electric motor 18 to approach the target assist amount. To do.

  2 and 3 are schematic perspective views of the steering assist mechanism 5, respectively, and are views of the steering assist mechanism 5 viewed from different angles. The main feature of the present embodiment is that the housing H for housing the ECU 12 as the control device is in contact with each other as shown in FIGS. 2 and 3 (for example, the end faces of each other are abutted against each other). The state is that the first housing 23 and the second housing 24 are in a state or a state in which the end portions are fitted to each other.

In other words, the first housing 23 and the second housing 24 that constitute the housing H for housing the ECU 12 are in contact with each other (directly engaged), and are separately provided between the housings 23 and 24. No housing is interposed. As a result, a significant reduction in size is achieved.
The first housing 23 and the second housing 24 are formed in a substantially square box shape with one end opened. The end portions of the first and second housings 23 and 24 are abutted and fastened to each other by a fixing screw 91.

  On the other hand, the motor housing 25 of the electric motor includes a cylindrical motor housing body 26 and the first housing 23 described above. Specifically, the first housing 23 that is a part of the housing H for housing the ECU 12 is formed integrally with at least a part of the motor housing 25 of the electric motor 12 from a single material. In other words, at least a part of the motor housing 25 and a part of the housing H for housing the ECU 12 are combined.

  The gear housing 22 includes a cylindrical drive gear housing 27 in which the worm shaft 20 is housed, a cylindrical driven gear housing 28 in which the worm wheel 21 is housed, and the second housing 24 described above. It is configured. Specifically, the second housing 24 that is a part of the housing H for housing the ECU 12 is formed integrally with the drive gear housing 27 and the driven gear housing 28 of the gear housing 22 from a single material. Has been. In other words, a part of the gear housing 22 is also used as a part of the housing H for housing the ECU 12.

  A cylindrical projection 93 projects from an outer periphery 92 a of the outer peripheral wall 92 as a side wall of the first housing 23, and an electrical connector 94 facing the outside of the first housing 23 is formed in the cylindrical projection 93. Is arranged. Although not shown, the electrical connector 94 is provided with terminals for supplying power from the battery to the ECU 12 and terminals for inputting and outputting signals from the outside.

  Referring to FIG. 4 which is a cross-sectional view of the main part of the electric power steering apparatus, the worm wheel 21 as the driven member of the speed reduction mechanism 19 (transmission mechanism) and the electrical connector 94 are the same as those of the speed reduction mechanism 19 (transmission mechanism). It is arranged on the same side with respect to a plane Q1 including the central axis C3 of the worm shaft 20 as the drive side member and parallel to the central axis 21a of the worm wheel 21.

In this case, when viewed along the axial direction X1 of the rotating shaft 37 of the electric motor 18, the electrical connector 94 and the driven gear housing 28 that serve as a projecting portion project to the same side. As a result, substantial downsizing and space saving can be achieved, and mountability on the vehicle is improved.
Further, with reference to FIG. 3, when viewed along an axial direction X1 of a rotating shaft 37 (to be described later) of the electric motor 18, the electrical connector 94 and the driven gear housing 28 have a layout in which at least a part of each other overlaps each other. Has been. Thereby, substantial miniaturization and space saving can be achieved, and the mounting property to the vehicle is improved.

Further, when viewed along the axial direction X1 of the rotary shaft 37, the electrical connector 94 and the sensor housing 35 have a layout in which at least a part of each other overlaps each other. Thereby, substantial miniaturization and space saving can be achieved, and the mounting property to the vehicle is improved.
The first housing 23 of the motor housing 25 is formed of, for example, an aluminum alloy (for example, a cast product or a cold forging product), and the steering assist mechanism 5 is reduced in weight. The gear housing 22 including the drive gear housing 27, the driven gear housing 28, and the second housing 24 is formed of, for example, an aluminum alloy (for example, a cast product or a cold forging product). The weight is reduced. Further, for example, a non-magnetic sheet metal is used for the motor housing body 26 of the motor housing 25.

The motor housing body 26 includes a cylindrical peripheral wall 29, a bottom wall 30 that closes one end of the peripheral wall 29, and an annular flange 31 that protrudes radially outward from the other end of the peripheral wall 29.
A bracket 32 projecting radially outward from a part of the annular flange 31 in the circumferential direction is provided. The motor housing body 26 and the first housing 23 are integrally fixed by screwing the fixing screw 34 inserted through the screw insertion hole 33 of the bracket 32 into the screw hole of the first housing 23. Since the screw insertion hole 33 is formed as a long hole extending in the circumferential direction of the motor housing body 26, the circumferential position of the motor housing body 26 can be adjusted with respect to the first housing 23. .

Further, the first housing 23 and the second housing 24 that constitute the housing H for housing the ECU 12 are fixed to each other using a fixing screw 91.
A cylindrical sensor housing 35 in which the torque sensor 11 is accommodated is connected to the driven gear accommodating housing 28 of the gear housing 22, and the driven gear accommodating housing 28 and the sensor housing 35 are fixed to each other using a fixing screw 36. Has been. The steering shaft 6 is inserted into the cylindrical driven gear housing 28 and the sensor housing 35.

  Referring to FIG. 4, a housing chamber 100 that houses ECU 12 as a control device by first housing 23 that is motor housing 25 of electric motor 18 and second housing 24 that is in contact with first housing 23. Is formed. The end surfaces of the first housing 23 and the second housing 24 are abutted with each other, and the both end surfaces are sealed with an annular seal member 95.

As shown in FIG. 6, the seal member 95 is accommodated in one of the first and second housings 23, 24, for example, an annular groove 99 formed in the end surface 98 of the second housing 24, and the other, For example, it contacts the end surface of the first housing 23 (corresponding to the end surface 88a of the flange 88). As the seal member 95, for example, an O-ring can be used.
Referring again to FIG. 4, the first housing 23 includes a first inner wall surface 101 that defines a part of the storage chamber 100, and the second housing 24 is a second that partitions a part of the storage chamber 100. The first inner wall surface 101 and the second inner wall surface 102 are opposed to the axial direction X1 of the rotating shaft 37 of the electric motor 18.

In addition, the second inner wall surface 102 of the second housing 24 is configured by an annular plane, and the annular plane is the central axis C1 of the rotating shaft 37 of the electric motor 18 or an extension line C2 ( Usually, it is orthogonal to the central axis C3 of the worm shaft 20 and surrounds the central axis C1 or the extension line C2.
The extended surface P1 of the annular plane formed by the second inner wall surface 102 intersects the cylindrical surface P2 formed by the main part of the outer peripheral surface 28a of the driven gear housing 28 as a cylindrical portion surrounding the steering shaft 6 as shown in FIG. You are in or are in contact. Specifically, the driven gear housing 28 surrounds the worm wheel 21 to which the steering shaft 6 is fitted.

Further, the ECU 12 as the control device is disposed around the central axis C1 or the extension line C2 of the rotating shaft 37.
A rotating shaft 37 and a worm shaft 20 of the electric motor 18 are arranged side by side on the same axis, and the rotating shaft 37 and the worm shaft 20 are coaxially connected to each other via a joint 38 interposed therebetween so that power can be transmitted. ing. The joint 38 is interposed between the input member 39 and the output member 40, the annular input member 39 that rotates together with the rotating shaft 37 of the electric motor 18, the annular output member 40 that rotates along with the worm shaft 20, and the input member 40. 39 and an output elastic member 41 for connecting the output member 40 so that power can be transmitted.

The worm shaft 20 is accommodated in the drive gear accommodation hole 42 of the drive gear accommodation housing 27 of the gear housing 22. The worm shaft 20 has a first end portion 20 a and a second end portion 20 b, and a worm 20 c is formed at an intermediate portion in the axial direction of the worm shaft 20.
The first end portion 20a of the worm shaft 20 can be rotated by a first bearing 45 held by a bearing holding portion 44 on the inner periphery of one end (end portion on the electric motor 18 side) of the drive gear accommodation hole 42. It is supported. The second end portion 20 b of the worm shaft 20 is rotatably supported by a second bearing 47 held by an inner peripheral bearing holding portion 46 at the other end of the drive gear accommodation hole 42.

  The first bearing 45 is a rolling bearing having an inner ring 48, an outer ring 49, and a plurality of rolling elements 50 interposed between the inner ring 48 and the outer ring 49. The inner ring 48 is held by the first end 20a of the worm shaft 20 so as to be able to rotate together. One end face of the inner ring 48 is in contact with a positioning step provided on the outer periphery of the worm shaft 20. A small-diameter protruding shaft 51 is extended from the first end portion 20a of the worm shaft 20, and the output member 40 of the joint 38 is fitted to the protruding shaft 51 so that the output member 40 can rotate together and cannot move in the axial direction. Are combined. The output member 40 is in contact with the other end surface of the inner ring 48, and the inner ring 48 is sandwiched between the positioning step portion of the worm shaft 20 and the output member 40. Thereby, the axial movement of the inner ring 45 relative to the worm shaft 20 is restricted.

  One end surface of the outer ring 49 is opposed to a step portion adjacent to one side of the bearing holding portion 44 of the drive gear accommodation hole 42 with a predetermined gap therebetween. An annular fixing member 52 is screwed into a screw portion adjacent to the other side of the bearing holding portion 44 of the drive gear accommodation hole 42, and the fixing member 52 presses the other end surface of the outer ring 49. Thereby, the axial movement of the outer ring 49 is restricted. The fixing member 52 includes a cylindrical main body 52a having a screw formed on the outer periphery, an inner flange 52b extending radially inward from one end of the main body 52a, and an outer extending radially outward from the other end of the main body 52a. And a flange 52c. The inner flange 52 b presses the other end surface of the outer ring 49. Further, the outer flange 52c is pressed against the second inner wall surface 102 of the second housing 24 that divides the accommodation chamber of the ECU 12, and thereby the locking of the fixing member 52 is achieved.

A part of the joint 38 is accommodated in the cylindrical main body 52 a of the fixing member 52. Thereby, size reduction of the electric power steering device 1 with respect to the axial direction X1 of the rotating shaft 37 is achieved.
The second bearing 47 is composed of a rolling bearing having an inner ring 53, an outer ring 54, and a plurality of rolling elements 55 interposed between the inner ring 53 and the outer ring 54. The inner ring 53 is held by the second end 20b of the worm shaft 20 so as to be able to rotate together. One end face of the inner ring 53 is in contact with a positioning step provided on the outer periphery of the worm shaft 20. Thereby, the axial movement (movement toward the first bearing 45) of the inner ring 53 with respect to the worm shaft 20 is restricted.

  A screw portion 56 is formed at the entrance portion of the drive gear accommodation hole 42 adjacent to the bearing holding portion 46 of the drive gear accommodation hole 42, and the first and second bearings 45 and 47 are formed in the screw portion 56. A preload application member 57 for applying preload in a lump is screwed in. The preload applying member 57 has a disk-shaped main body 58, and a screw portion 59 that is screwed into the screw portion 56 is formed on the outer periphery of the main body 58. An annular convex portion 60 that presses one end surface of the outer ring 54 of the second bearing 47 is formed on one end surface of the main body 58.

A tool engagement hole 61 having a polygonal cross section, for example, is formed on the other end surface of the main body 58 to engage with a tool for rotating the preload applying member 57. Further, the preload applying member 57 is fixed by a lock nut 62 screwed into the threaded portion 59 of the main body 58.
The first and second bearings 45 and 47 that support the first and second end portions 20a and 20b of the worm shaft 20 are both configured by known seal bearings. Specifically, a seal member 62 that seals between the inner ring and the outer ring is provided on both sides of the rolling element in the axial direction X1, and the seal member 62 is fixed to either the inner ring or the outer ring. Further, the seal member 62 has a lip that is in sliding contact with the other.

  Since the first and second bearings 45 and 47 that support both ends of the worm shaft 20 are constituted by seal bearings, lubricant such as grease in the gear housing 22 leaks to the accommodation chamber 100 side in which the ECU 12 is accommodated. I don't get out. However, in order to improve the sealing performance in the storage chamber 100, for example, a liquid packing may be interposed between the screw portion on the outer periphery of the main body 52a of the fixing member 52 and the screw portion screwed into the screw portion.

In the present embodiment, a brushless motor is used as the electric motor 18. The electric motor 18 includes the motor housing 25, and a rotor 64 and a stator 65 accommodated in the motor housing 25.
The rotor 64 includes an annular rotor core 66 attached to the outer periphery of the rotary shaft 37 so as to be able to rotate along with the rotor shaft 67, and a rotor magnet 67 made of, for example, an annular permanent magnet attached to the outer periphery of the rotor core 66 so as to be able to rotate along with the rotor. Yes. In the rotor magnet 67, a plurality of magnetic poles are arranged side by side in the circumferential direction. These magnetic poles are configured so that the N pole and the S pole are alternately switched in the circumferential direction of the rotor 64.

  The stator 65 is fixed to the inner periphery of the motor housing body 26 of the motor housing 25. The stator 65 includes a stator core 68 fixed to the inner periphery of the motor housing body 26 and a plurality of coils 69. Stator core 68 includes an annular yoke and a plurality of teeth protruding radially inward from the inner periphery of the yoke. Each coil 69 is wound around a corresponding tooth.

  A bus bar 71 having an annular shape or a C shape is accommodated in the motor chamber 70 defined by the motor housing main body 26 and the first housing 23 of the motor housing 25. The coil 69 wound around each tooth is connected to the bus bar 71. The bus bar 71 is a conductive connection material used for a connection portion between each coil 69 and the current application line, and the bus bar 71 functions as a power distribution member for distributing power from a power supply source (not shown) to each coil 69. To do.

  A rotation position detection device 72 for detecting the rotation position of the rotor 64 is accommodated in the motor chamber 70 defined by the motor housing main body 26 and the first housing 23 of the motor housing 25. The rotational position detection device 72 has a stator 73 fixed to the first housing 23 and a rotor 74 attached to the rotational shaft 37 so as to be able to rotate together. As the rotational position detecting device 72, for example, a resolver can be used. A Hall element can also be used.

  The rotational position detection device 72 may be disposed between the rotor core 66 of the rotor 64 of the electric motor 18 and the second housing 24 with respect to the axial direction X1 of the rotation shaft 37 of the electric motor 18. Therefore, as in the present embodiment, it may be arranged in the motor chamber 70, or in a cylindrical portion 89 (described later) provided in the center of the first housing 23 that defines the storage chamber 100 of the ECU 12. It may be arranged.

  Referring to FIG. 4, the rotary shaft 37 includes third and fourth bearings 75 and 4 held by the first housing 23 that serves as both a part of the motor housing 25 and a part of the housing that houses the ECU 12. The bearing 76 is rotatably supported. The third and fourth bearings 75 and 76 are constituted by seal bearings having the same configuration as the first and second bearings 45 and 47.

  The first housing 23, which is a part of the housing H that partitions the storage chamber 100 of the ECU 12, includes a partition wall 77 that partitions the storage chamber 100 and the motor chamber 70 as a bottom wall. The partition wall 77 is provided with the first inner wall surface 101. A cylindrical projection 104 extends from the vicinity of the outer periphery of the partition wall 77 toward the motor housing body 26, and one end of the motor housing body 26 is fitted to the outer periphery of the cylindrical projection 104.

  The partition wall 77 has a holding hole 105 for holding the outer ring of the third bearing 75. A cylindrical projection 106 extending from the partition wall 77 toward the motor housing body 26 is formed. The cylindrical protrusion 106 is formed coaxially with the holding hole 105. The cylindrical projection 106 is formed with a smaller diameter than the cylindrical projection 104 that engages with the motor housing body 26. A stator 73 of the rotational position detecting device 72 is fixed to the inner periphery of the cylindrical protrusion 106.

  Further, a cylindrical portion 89 extending from the partition wall 77 toward the second housing 24 is formed. The cylindrical portion 89 is formed coaxially with the holding hole 105. The outer ring of the fourth bearing 76 is held on the inner periphery of the cylindrical portion 89. An annular flange 107 extending radially inward is extended at one end of the cylindrical portion 89, and one end of the outer ring of the fourth bearing 76 abuts on the annular flange 107, so The axial movement of the outer ring of the fourth bearing 76 is restricted.

On the other hand, the inner ring of the fourth bearing 76 is sandwiched between an annular positioning step formed on the outer periphery of the rotating shaft 37 and the end face of the input member 39 of the joint 38, whereby the rotating shaft 37. The axial movement of the inner ring of the fourth bearing 76 is restricted.
In the accommodation chamber 100, a power board 78 and a control board 79 that constitute a part of the ECU 12 are accommodated and held. On the power board 78, at least a part of a power circuit (for example, a switching element such as an FET) for driving the electric motor 18 is mounted. The bus bar 71 connected to each coil 69 is connected to the power board 78 via a bus bar terminal 80 that passes through the partition wall 77 of the first housing 23 and enters the housing chamber 100.

In addition, the rotational position detection device 72 is connected to the control board 79 via a bus bar terminal 81 that passes through the partition wall 77 of the first housing 23 and enters the storage chamber 100.
In the storage chamber 100, the power board 78 on which the power circuit is mounted is disposed relatively close to the first inner wall surface 101 among the first inner wall surface 101 and the second inner wall surface 102. That is, the partition wall 77 includes a thick portion 77a and a relatively thin portion 77b that have a relatively thick thickness t1 in the axial direction X1 of the rotating shaft 37 of the electric motor 18. The thick portion 77a is provided so as to protrude into the storage chamber 100.

The power board 78 is arranged close to or in contact with the first inner wall surface 101 in the thick portion 77a. Specifically, in the first inner wall surface 101, the thick portion 77 a is a seat portion 103 that receives the power board 78.
In the present embodiment, the power substrate 78 is in contact with the first inner wall surface 101 in the thick portion 77a so as to be capable of conducting heat, and the thick portion 77a is for releasing the heat of the power substrate 78. It functions as a heat sink.

The input member 39 of the joint 38 has a cylindrical portion 39 a that is fitted to the end portion of the rotating shaft 37 of the electric motor 18 so as to be able to rotate together. The control board 79 is formed of the cylindrical portion 39 a of the input member 39. It is arranged around. Specifically, the cylindrical portion 39 a is inserted through the insertion hole 79 a in the center of the control board 79.
The control board 79 is disposed between the second inner wall surface 102 of the second housing 24 and the power board 78 with respect to the axial direction X1 of the rotating shaft 37 of the electric motor 18. The power board 78 and the control board 79 are arranged at a predetermined interval with respect to the axial direction X1 of the rotating shaft 37 of the electric motor 18. Further, the control board 79 and the joint 38 are laid out so that at least a part of each other overlaps in the direction along the central axis C1 of the rotating shaft 37 of the electric motor 18.

  In the accommodation chamber 100, the accommodation space S <b> 1 formed between the thin wall portion 77 b of the partition wall 77 of the first housing 23 and the control board 79 is sufficient with respect to the axial direction X <b> 1 of the rotating shaft 37 of the electric motor 18. Has a height. Although not shown in FIG. 4, the housing space S1 accommodates relatively large and tall parts such as a plurality of capacitors 85 and relays 86 shown in FIG. The space in the room 100 is effectively used.

  Next, referring to FIG. 5, which is an exploded perspective view, a power circuit 82 is mounted on the power board 78 as a motor drive circuit for driving the electric motor 18. Referring to FIGS. 5 and 7, power circuit 82 mounted on power board 78 includes a plurality of FETs 83 (electrolytic effect type transistors) as switching elements and a plurality of snubbers for reducing switching noise caused by FETs 83. A circuit 200 is included. The power board 78 constitutes a laminated circuit board which is a motor control device having a circuit mounted on one side. The power substrate 78 includes a substrate main body 301 and a metal base 302 as a high thermal conductive plate made of, for example, an aluminum plate that is in surface contact with the thick portion 77a as a heat sink.

  A control circuit 84 for controlling the power circuit 82 that drives the electric motor 18 is mounted on the control board 79. The control circuit 84 mounted on the control board 79 is arranged around the central axis C1 of the rotating shaft 37 of the electric motor 18 (or an extension line C2 of the central axis C1). The control circuit 84 includes a driver that controls each FET 83 of the power circuit 82 and a CPU that controls the driver.

  Further, the ECU 12 includes the plurality of capacitors 85 described above, a relay 86 for cutting off the current flowing through the electric motor 18 as necessary, and other non-heating elements. The capacitor 85 is a smoothing electrolytic capacitor that is disposed in a power line to the electric motor 18 and removes a ripple of a current flowing through the electric motor 18. Typically, this type of capacitor 85 is large in capacity and large. The capacitor 85, the relay 86, and the like as non-heat generating elements constitute a subassembly SA supported by an annular synthetic resin holder 120, and can be collectively attached to the first housing 23. It has become.

Each capacitor 85 is held in a laid-down state by, for example, an angle-shaped holding portion 121 provided in the holder 120. That is, by arranging the longitudinal direction of the large capacitor 85 in a direction perpendicular to the direction parallel to the central axis C1, the storage chamber 100 can be downsized in the direction along the central axis C1. It has been.
The first housing 23 is a substantially square box-shaped member having one end opened. Specifically, the first housing 23 includes a generally rectangular box-shaped main body 87 having one end opened. The main body 87 has a substantially annular outer peripheral wall 92, a rectangular annular flange 88 projecting radially outward from one end of the outer peripheral wall 92, and the partition wall 77 as a bottom wall. .

In the storage chamber 100, a cylindrical portion 89 extending toward the open side (the second housing 24 side) of the main body 87 is formed at the central portion of the partition wall 77. The outer peripheral wall 92 extends from the outer peripheral edge of the partition wall 77 and surrounds the tubular portion 89. The main body 87 and the cylindrical portion 89 are integrally formed of a single member.
An end surface 88a (the upper surface in FIG. 5) of the flange 88 is flat. The sealing member 95 comes into contact with the end surface 88a. Further, the flange 88 has a plurality of (a pair in the present embodiment) bracket-shaped attachment portions 96 protruding outward in the radial direction. Each attachment portion 96 is formed with a screw insertion hole 97 that penetrates the attachment portion 96 in the thickness direction. The fixing screws 91 for fastening the first and second housings 23 and 24 are inserted through the screw insertion holes 97.

The outer peripheral wall 92 having a quadrangular annular shape has four side walls 111 to 114, and the mounting portion 96 is extended at the ends of a pair of opposing side walls 112 and 114. Further, the thick portion 77a of the partition wall 77 that functions as the heat sink is formed continuously on the inner surface of one side wall 112 on which the mounting portion 96 is extended.
Of the first inner wall surface 101, a portion in the thick portion 77 a constitutes a seat portion 103 that receives the power board 78. The seat portion 103 is in contact with a power substrate 78 having an FET 83 as a heat generating element so as to allow heat conduction. The heat of the heat generating element is released from the power board 78 to the side of the gear housing 22 integrated with the second housing 24 through the thick portion 77a and the mounting portion 96 constituting the heat sink.

In the attachment portion 96 used for fastening by the fixing screw 91, the contact area with respect to the second housing 24 is wide as compared with other portions of the flange 88. A thick wall 77a serving as a heat sink having a large heat capacity is provided continuously to the side wall 112 provided with the mounting portion 96.
After the power board 78 is attached to the seat 103, the subassembly SA including the capacitor 85, the relay 86, and the holder 120 is attached. At this time, since the central portion of the annular holder 120 is largely open, most of the surface of the power board 78 is not covered by the holder 120 and is open. Thereby, a sufficient heat radiation space adjacent to the surface of the power board 78 is ensured.

FIG. 8 is a cross-sectional view of the main part showing a state in which the power board 78 is fixed to the thick part 77 a of the first housing 23. Referring to FIG. 8, thick portion 77a is provided as a substrate installation member. One side surface 303 of the thick portion 77a extends flatly perpendicular to the axis C1. A power board 78 is installed on the one side surface 303.
The power board 78 includes a board body 301, a metal base 302, and a covering member 304.

  The substrate body 301 is formed by laminating an insulating layer made of an insulator and a layer containing a conductor. Specifically, the substrate body 301 includes a first layer 311, a second layer 312, a third layer 313, a fourth layer 314, and a fifth layer as surface layers of the substrate body 301. 315, a sixth layer 316, and a seventh layer 317 as a back layer of the substrate body 301. The first to seventh layers 311 to 317 are arranged in this order along the stacking direction D along the axis C1.

  The first, third, fifth, and seventh layers 311, 313, 315, and 317 as the odd-numbered layers constitute an insulating layer made of an insulator. As this insulator, what added the heat conductive material higher in heat conductivity than synthetic resin materials, such as a ceramic powder and glass fiber, to the synthetic resin material as a base material can be illustrated. Thereby, the thermal conductivity of the substrate body 301 is increased, and the thermal resistance is reduced.

The second, fourth, and sixth layers 312, 314, and 316 as even-numbered layers each constitute a layer that includes a conductor.
The second layer 312 includes a conductive portion 312a as a conductor and an insulating portion 312b as an insulator. The conductive portion 312a is formed using a metal such as copper. The insulating portion 312b is formed using the same material as that of the first layer 311 and surrounds the conductive portion 312a.

The fourth layer 314 includes a conductive portion 314a as a conductor and an insulating portion 314b as an insulator. The conductive portion 314a is formed using the same material as that of the conductive portion 312a. The insulating portion 314b is formed using the same material as that of the first layer 311 and surrounds the conductive portion 314a.
The sixth layer 316 includes conductive portions 316a and 316b as conductors and an insulating portion 316c as an insulator. Each of the conductive portions 316a and 316b is formed using the same material as that of the conductive portion 312a of the second layer 312. The insulating portion 316c is formed using a material similar to that of the first layer 311. The insulating portion 316c surrounds the conductive portions 316a and 316b so that the conductive portions 316a and 316b do not directly contact each other.

A part of the conductive part 312 a of the second layer 312 and a part of the conductive part 316 a of the sixth layer 316 are opposed to each other in the stacking direction D. In addition, a part of the conductive part 314 a of the fourth layer 314 and a part of the conductive part 316 b of the sixth layer 316 are opposed to each other in the stacking direction D.
Conductive portions 305a, 305b, and 305c are provided on the surface of the first layer 311, that is, the surface 301a of the substrate body 301, respectively. Each of the conductive portions 305a, 305b, and 305c is formed using the same material as that of the conductive portion 312a of the second layer 312.

Each of the conductive portion 305a, the conductive portion 312a of the second layer 312 and the conductive portion 316a of the sixth layer 316 faces each other in the stacking direction D.
A part of each of the conductive portion 305b and the conductive portion 312a of the second layer 312 is opposed to each other in the stacking direction D.
Each of the conductive portion 305c, the conductive portion 314a of the fourth layer 314, and the conductive portion 316b of the sixth layer 316 are opposed to each other in the stacking direction D.

  A plating layer 306 is formed on the surface of the conductive portion 305a. The plating layer 306 is, for example, nickel gold plating (Ni + Au plating). An FET 83 as a motor driving element is joined to the surface of the plating layer 306 using solder 307. Thereby, the FET 83 is joined to the conductive portion 305a. That is, the FET 83 is bare chip mounted on the substrate body 301.

Via holes 308 a to 308 g for increasing the heat dissipation of the substrate body 301 are formed in the substrate body 301. Note that the via hole of the substrate body 301 is simply referred to as a via hole 308 when collectively referred to.
Each of the via holes 308a to 308g is an interlayer connection hole that penetrates a layer other than the seventh layer 307 as the back surface of the substrate body 301, that is, the first to sixth layers 311 to 316. The via holes 308a to 308d are formed corresponding to the conductive portion 305a on which the FET 83 is mounted. The via hole 308e is formed corresponding to the conductive portion 305b. The via holes 308f and 308g are formed corresponding to the conductive portion 305c.

The via holes 308a to 308d include the conductive portion 305a, the first layer 311, the conductive portion 312a of the second layer 312, the third layer 313, the insulating portion 314b of the fourth layer 314, the fifth layer 315, and The conductive portion 316a of the sixth layer 316 is penetrated.
The via hole 308e includes a conductive portion 305b, a first layer 311, a conductive portion 312a of the second layer 312, a third layer 313, an insulating portion 314b of the fourth layer 314, a fifth layer 315, and a sixth layer. The insulating portion 316c of the layer 316 is penetrated.

The via holes 308 f and 308 g include the first layer 311, the insulating portion 312 b of the second layer 312, the third layer 313, the conductive portion 314 a of the fourth layer 314, the fifth layer 315, and the sixth layer 316. Through the conductive portion 316b.
A pin member 309 made of metal such as copper is press-fitted and fixed in each of the via holes 308a to 308d. As a result, the conductive portion 305a, the conductive portion 312a of the second layer 312 and the conductive portion 316a of the sixth layer 316 are electrically connected via the pin member 309.

Similarly, a pin member 309 is press-fitted and fixed in the via hole 308e. Accordingly, the conductive portion 305b and the conductive portion 312a of the second layer 312 are electrically connected.
Similarly, a pin member 309 is press-fitted and fixed in the via holes 308f and 308g. Thus, the conductive portion 305c, the conductive portion 314a of the fourth layer 314, and the sixth conductive portion 316b are electrically connected.

With the above configuration, the heat from each of the conductive portions 305a, 305b, and 305c is transferred to the seventh layer 317 via the corresponding pin member 309, and further from the metal base 302 to the thick portion 77a of the first housing 23. It is transmitted to.
Since the FET 83 functions as a switching element, it generates a large amount of heat. Therefore, a plurality of pin members 309 are provided corresponding to the conductive portion 305a on which the FET 83 is mounted. Thereby, more heat from the FET 83 can be transmitted to the thick portion 77a.

In addition, since each pin member 309 does not penetrate the seventh layer 317, it is possible to prevent each pin member 309 from contacting the metal base 302 and to prevent both from being electrically connected.
In the substrate body 301, the first layer 311 forms the front surface 301 a of the substrate body 301, and the seventh layer 317 forms the back surface 301 b of the substrate body 301. These front surface 301a and back surface 301b are opposed to each other in the stacking direction D. In the substrate main body 301, the first to seventh layers 311 to 317 cooperate to constitute the outer surface 301 c of the substrate main body 301. The outer side surface 301c has an annular shape as a whole.

As will be described later, the substrate body 301 is formed by punching a plate-shaped manufacturing intermediate formed by pressing an insulator and a layer containing a conductor. Therefore, the resin, glass fiber, ceramic, or the like constituting the substrate body 301 may adhere to the outer surface 301c of the substrate body 301 as dust (foreign matter).
One of the features of this embodiment is that the outer surface 301c is entirely covered with a covering member 304, thereby preventing foreign matter from scattering from the outer surface 301c of the substrate body 301.

  The covering member 304 is formed into a thin film by coating a predetermined material on the outer side surface 301 c of the substrate body 301. Examples of the material constituting the covering member 304 include polyimide resin (PI), epoxy resin (EP), and silicon resin (SI). The outer surface 304 a of the covering member 304 is formed as a smooth surface parallel to the outer surface 301 c of the substrate body 301.

  The metal base 302 is provided as a heat sink and is formed in a shape that matches the substrate body 301 when viewed along the stacking direction D. As described above, the metal base 302 is formed using a material having excellent thermal conductivity such as an aluminum alloy. The metal base 302 includes a front surface 302 a and a back surface 302 b that face each other in the stacking direction D. These front surface 302a and back surface 302b are parallel to each other. The front surface 302a of the metal base 302 is fixed to the back surface 301b of the substrate body 301 using an adhesive or the like, and both are in surface contact with each other.

The entire back surface 302b of the metal base 302 is in surface contact with one side surface 303 of the thick portion 77a. Thereby, the heat transmitted from the substrate body 301 to the metal base 302 can be sufficiently released to the thick portion 77a.
In relation to the metal base 302, positioning members 318 and 319 are provided. The positioning members 318 and 319 are for accurately positioning the power board 78 with respect to the thick portion 77a of the first housing 23, and are formed using an insulator.

Each positioning member 318, 319 is formed in a rod shape extending in the stacking direction D, and both one end and the other end are formed in a tapered shape.
One positioning member 318 has one end fitted in a first positioning hole 321a formed in the back surface 302b of the metal base 302, and the other end formed on one side 303 of the thick portion 77a. The second positioning hole 322a is fitted. Each of the first and second positioning holes 321 a and 322 a is formed in a shape that matches the shape of the corresponding one end and the other end of the positioning member 318. Note that one positioning member 318 may be integrally formed of the same material as that of the first housing 23.

  The other positioning member 319 is fitted into both the first positioning hole 321b and the second positioning hole 322b. The first positioning hole 321 b penetrates both the substrate body 301 and the metal base 302. The intermediate portion of the other positioning member 319 is inserted through the substrate body 301, the metal base 302, and the thick portion 77a. A part of the first positioning hole 321b on the substrate body 301 side is formed in a tapered shape that matches the outer diameter shape of the other positioning member 319, and one end of the other positioning member 319 is fitted. ing.

  The second positioning hole 322b is formed on one side surface 303 of the thick portion 77a. The other end of the other positioning member 319 is fitted in the second positioning hole 322b. The second positioning hole 322b is formed in a shape that matches the shape of the corresponding other end portion of the other positioning member 319. Note that the other positioning member 319 may be integrally formed of the same material as that of the first housing 23.

One positioning member 318 and the other positioning member 319 are spaced apart from each other, and the positioning member 318, 319 indicates that the power board 78 rotates around one of the positioning members 318, 319. Are working together to prevent it.
The power board 78 is fixed to the thick portion 77a using a screw member 325. Specifically, screw insertion holes 323 are formed through the power board 78. A screw hole 324 is formed in the thick portion 77a at a location corresponding to the screw insertion hole 323. The power board 78 is fixed to the thick portion 77a by the screw insertion hole 323 and the screw member 325 that passes through the screw hole 324. Although not shown, a screw fastening structure using the screw member 325 is also provided in another part of the power board 78, and the power board 78 is firmly fixed to the thick portion 77a.

FIG. 9 is a cross-sectional view of a main part taken along line IX-IX in FIG. Referring to FIG. 9, conductive surface 305d and conductive portion 305e are provided on surface 301a of substrate body 301. A nickel gold plating layer 306 is formed on the surface of the conductive portion 305e. An FET 83 is bare-chip mounted on the nickel gold plating layer 306 using solder 307.
The conductive portion 305d and the FET 83 are electrically connected using wire bonding. Specifically, one end of the bonding wire 310 is bonded to the surface of the conductive portion 305d, and the other end of the bonding wire 310 is bonded to the surface of the FET 83.

  The conductive portion 305d is provided with a joining portion 326 for joining by wire bonding and a non-joining portion 327 arranged so as to avoid the joining portion 326. The junction portion 326 is provided in a part of the conductive portion 305d located near the FET 83, and is formed on a smooth surface. One end of the bonding wire 310 is bonded to the bonding portion 326. That is, one end of the bonding wire 310 is bonded to the conductive portion 305d without using a bonding pad. By electrically connecting the conductive portion 305d and the FET 83 with a stretchable bonding wire, the thermal stress generated in both can be reduced.

The non-joining portion 327 is disposed at a position farther from the FET 83 than the joining portion 326, and does not overlap the stacking direction D with the joining portion 326. The power substrate 78 is formed with a via hole 308 h that penetrates the non-joining portion 327 and the first to sixth layers 311 to 316. The joint portion 326 is disposed so as to avoid the via hole 308 h in the stacking direction D.
Of the surface 301a of the substrate main body 301, a portion where the via hole 308h is formed (non-joining portion 327) has unevenness caused by punching the substrate main body 301 to form the via hole 308h, as will be described later. . In addition, since this unevenness | corrugation is minute, it is not illustrated in FIG. This unevenness is not preferable in order to ensure sufficient bonding strength by sufficiently pressing one end of the bonding wire 310. By bonding one end of the bonding wire 310 to the bonding portion 326 where such unevenness does not occur, one end of the bonding wire 310 can be bonded to the conductive portion 305d with sufficient strength.

The via hole 308h is an interlayer connection hole similar to the above-described via holes 308a to 308g. For example, the non-joining portion 327, the first layer 311, the conductive portion 312c of the second layer 312, the third layer 313, the fourth The insulating layer 314b of the first layer 314, the fifth layer 315, and the insulating portion 316c of the sixth layer 316 are penetrated.
A pin member 309 is press-fitted into the via hole 308h, and electrically connects the conductive portion 305d and the conductive portion 312c of the second layer 312.

Via holes 308i to 308l similar to the via hole 308h are also formed in the conductive portion 305e. A pin member 309 is press-fitted into each of the via holes 308i to 308l, and electrically connects, for example, the conductive portion 305e and the conductive portion 316d of the sixth layer 316.
Referring to FIG. 7, conductive portions 305f, 305g, and 305h are provided on one side edge of substrate body 301. Each of the conductive portions 305f, 305g, and 305h includes a joint portion 326 and a non-joint portion 327 similarly to the conductive portion 305d. One end of a bonding wire 310 is joined to each joint 326 of each conductive part 305f, 305g, 305h. The other end of each bonding wire 310 is bonded to the bus bar terminal 80. Each non-joining portion 327 is provided with a pin member 309.

  The power board 78 having the above schematic configuration is manufactured, for example, as follows. Referring to FIG. 10A, first, a production intermediate 331 formed by providing a plurality of conductive portions 305a, 305b, 305c and first to seventh layers 311 to 317 side by side is pressed. Punched with member 338. Thereby, as shown in FIG. 10B, a manufacturing intermediate 332 including the conductive portions 305a, 305b, 305c and the first to seventh layers 311 to 317 is formed.

Next, a coating is applied to the entire outer surface of the production intermediate 332. Thereby, the covering member 304 is formed as shown in FIG. Thereby, it is prevented that the synthetic resin, glass fiber, or ceramic powder as the material of the first to seventh layers 311 to 317 is scattered.
Next, holes are formed in the production intermediate 332. Specifically, the first positioning hole 321 b is formed using the punch member 339. In addition, each via hole 308 such as the via holes 308 a to 308 g is formed using the punch member 340. Further, the screw insertion hole 323 is formed using the punch member 341. Thereby, the production intermediate 333 is formed.

  Next, as shown in FIG. 11A, the pin member 309 is press-fitted and fixed in each via hole 308 such as the via holes 308a to 308g. In addition, before the pin member 309 is press-fitted and fixed to each via hole 308 such as the via holes 308a to 308g, a copper plating layer may be formed on the inner peripheral surface of these via holes 308. Further, the pin member 309 may be inserted into the corresponding via hole 308 not by press-fitting but by clearance fitting, and the pin member 309 may be fixed to the corresponding via hole 308 using a conductive adhesive.

Next, as shown in FIG. 11B, a plating layer 306 is formed on a conductive portion (conductive portion 305a and the like) to which members such as FETs and bonding wires are bonded. Thereby, the substrate body 301 is formed.
Next, as shown in FIG. 12A, the power substrate 78 is formed by fixing the surface 302a of the metal base 302 to the back surface 301b of the substrate body 301 using an adhesive or the like. Thereafter, as shown in FIG. 12B, the surface 301a of the substrate main body 301 of the power substrate 78 is placed in an oxygen plasma atmosphere, whereby the surface of the plating layer 306 is cleaned.

  Specifically, the power substrate 78 is accommodated in the processing chamber 343 that forms a sealed space. The processing chamber 343 is filled with oxygen plasma that has passed through the plasma generator 344. The temperature in the processing chamber 343 is set so that, for example, the temperature of the surface 301a of the substrate body 301 is 100 ° C. or lower. In addition, a vacuum pump 345 is connected to the processing chamber 343, and the inside of the processing chamber 343 is kept in a vacuum state.

After the substrate body 301 is placed in an oxygen plasma atmosphere, the substrate body 301 is placed in a hydrogen plasma atmosphere as shown in FIG. The process shown in FIG. 12C is different from the process shown in FIG. 12B in that hydrogen plasma is used instead of oxygen plasma.
As described above, the carbon formed on the plating layer 306 on the surface 301a of the substrate body 301 by applying hydrogen plasma next to the oxygen plasma to the surface 301a of the substrate body 301 in a vacuum state (negative pressure state). Compounds and oxides can be removed by a reduction reaction.

As a result, it is possible to prevent voids from being generated in the solder 307 during solder reflow described later, and to suppress the bonding strength of members using the solder 307 and heat generation during the operation of the FET. Furthermore, the fillet shape of the solder 307 can be stabilized, and the bonding strength using the solder 307 can be further improved.
Note that the step of applying argon plasma to the surface 301 a of the substrate body 301 may be performed before and after the step of applying oxygen plasma to the surface 301 a of the substrate body 301.

Next, as shown in FIG. 13A, the FET 83 is mounted on the conductive portion 305a of the power substrate 78, and the power substrate 78 is sent into the reflow furnace 346 as shown in FIG. Thereafter, the power substrate 78 is taken out from the reflow furnace 346. Thereby, the solder 307 is fixed to the FET 83 and the plating layer 306, and the FET 83 is joined to the conductive portion 305a.
As described above, according to the present embodiment, since the outer surface 301c of the substrate body 301 is covered with the covering member 304, the material constituting the insulating layer is dust (foreign matter) from the outer surface 301c. ) Can be prevented from scattering.

Thereby, it can prevent that a foreign material adheres to the surface 301a etc. of the board | substrate body 301, and can prevent the joining defect at the time of joining electronic components, such as FET83, to the board | substrate body 301 reliably.
The first, third, fifth, and seventh layers 311, 313, 315, and 317 as insulating layers are made of ceramic powder or the like as a heat conductive material having a higher thermal conductivity than a synthetic resin as a base material. Contains. Thereby, the thermal conductivity of the first, third, fifth, and seventh layers 311, 313, 315, and 317 can be increased, and the heat dissipation of the substrate body 301 can be further increased.

  Further, the bonding portion 326 for bonding by wire bonding is arranged in the stacking direction D while avoiding the via hole 308. The portion of the substrate main body 301 where the via hole 308 is formed becomes uneven due to the forming operation using the punch of the via hole 308. On the other hand, in the portion where the via hole 308 is not formed, the work for forming the via hole 308 is not performed, so that the surface 301 a of the substrate body 301 is not uneven.

  As described above, since the joint portion 326 is provided in a smooth portion of the surface 301a of the substrate body 301 where there is no unevenness, the joint portion 326 and the bonding wire 310 bonded to the joint portion 326 are reliably joined. Therefore, the bonding strength between the two can be sufficiently ensured. In addition, since it is not necessary to form the joint portion 326 using another component such as a bonding pad, the cost is low.

Further, by using the positioning members 318 and 319, the accuracy of positioning the power board 78 with respect to the thick portion 77a of the first housing 23 can be further increased.
Further, since dust (foreign matter) is prevented from being generated from the substrate body 301, such foreign matter enters the respective bearings 75, 76 of the electric motor 18 and wear of these bearings 75, 76 is accelerated. Can be prevented.

Moreover, since sufficient heat dissipation is ensured by providing a large number of via holes 308, a space for heat dissipation can be reduced, and further miniaturization of the power board 78 can be achieved.
As described above, it is possible to realize the electric power steering apparatus 1 in which the bonding failure of various electronic components mounted on the board body 301 is reliably prevented and the wear of the bearings 75 and 76 of the electric motor 18 is suppressed. it can.

  Further, a rotational position detection device 72 that detects the rotational position of the rotor 64 of the electric motor 18 is arranged between the rotor 64 of the electric motor 18 and the second housing 24 with respect to the axial direction X1 of the rotation shaft 37 of the electric motor 18. Since it has been arranged, the rotational position detecting device 72 can be arranged close to the ECU 12. As a result, the rotational position detection device 72 and the ECU 12 can be easily connected by the bus bar terminal 81 as an internal wiring having a short path length. Therefore, compared to the conventional case where external wiring having a long path length is used, it is less susceptible to radio noise. In addition, wiring members for external wiring can be reduced.

  In addition, the second inner wall surface 102 of the second housing 24 that divides a part of the storage chamber 100 is orthogonal to the central axis C1 (or an extension line C2 thereof) of the rotating shaft 37 of the electric motor 18 and the central axis. It includes an annular plane that surrounds C1 (or its extension C2). That is, there is no unnecessary protrusion in the storage chamber 100 in the axial direction X1 of the rotating shaft 37 of the electric motor 18. Therefore, even if the storage chamber 100 is small with respect to the axial direction X1, a sufficient internal volume as the storage chamber 100 can be ensured, and the electric power steering apparatus 1 can be miniaturized as much as possible.

  Further, since the second housing 24 is the gear housing 22 in which the speed reduction mechanism 19 as a transmission mechanism for transmitting the power of the electric motor 18 to the steering mechanism 4 is accommodated, there are the following advantages. That is, the ECU 12 typically includes a heating element such as a switching element (FET 83) mounted on the power board 78 as in the present embodiment. On the other hand, the speed reduction mechanism 19 hardly generates heat. The heat from the heat generating element can be effectively released to the outside of the storage chamber 100 through the gear housing 22 in which the speed reduction mechanism 19 is stored.

Further, since the control board 79 and the joint 38 are arranged so that at least a part of each other overlaps in the direction along the central axis C1 of the rotating shaft 37 of the electric motor 18, the electric power steering device 1 is further reduced in size. be able to.
An outer peripheral surface of the driven gear housing 28 as a cylindrical portion surrounding the shaft (corresponding to the steering shaft 6 in the present embodiment) of the annular flat surface formed by the second inner wall surface 102 and transmitting the steering force. The cylindrical surface P2 formed by the main part of the surface 28a intersects or is in contact with the cylindrical surface P2 as shown in FIG. Accordingly, the storage chamber 100 is disposed sufficiently close to the steering shaft 6 side with respect to the axial direction X1 of the rotating shaft 37 of the electric motor 18, and the electric power steering device 1 is disposed with respect to the axial direction X1 of the rotating shaft 37. It can be made smaller.

  The shaft for transmitting the steering force is not limited to the steering shaft 6 described above, but may be a pinion shaft 13 of a rack and pinion mechanism as the steering mechanism 4 or a rack shaft 14. Also good. In the former case, the cylindrical surface formed by the main part of the outer peripheral surface of a cylindrical pinion housing (not shown) surrounding the pinion shaft 13 and the extension surface P1 intersect or contact each other. In the latter case, the cylindrical surface formed by the main part of the outer peripheral surface of a cylindrical rack housing (not shown) surrounding the rack shaft 14 and the extension surface P1 intersect or contact each other.

Further, since the ECU 12 as the control device is arranged around the central axis C1 of the rotating shaft 37 of the electric motor 18 or the extension line C2 of the central axis C1, the space inside the accommodation chamber 100 is effectively used for the arrangement of the ECU 12. Therefore, the electric power steering apparatus 1 can be made smaller with respect to the axial direction X1 of the rotating shaft 37.
The first housing 23 includes a partition wall 77 that partitions the housing chamber 100 and the motor chamber 70, and a power board 78 is provided relatively close to the first inner wall surface 101 of the partition wall 77. Yes. In particular, the power substrate 78 is in contact with the first inner wall surface 101 in the thick portion 77a of the partition wall 77 so as to be capable of conducting heat. Therefore, by using the thick portion 77a of the partition wall 77 of the first housing 23 as a heat sink, the heat of the power board 78 having a heat generating element such as the FET 83 is contacted from the first housing 23 to the second housing. It can escape effectively to 24 side.

In the accommodation chamber 100, the accommodation space S <b> 1 that faces the thin portion 77 b of the partition wall 77 of the first housing 23 has a sufficient height with respect to the axial direction X <b> 1 of the rotating shaft 37 of the electric motor 18. In this accommodation space S1, effective use of the space in the accommodation chamber 100 is achieved by accommodating tall components such as the capacitor 85 and the relay 86 shown in FIG.
Further, although not shown, a structure in which a housing that houses a steering angle sensor as a steering state detection sensor that detects a steering angle of the steering wheel 2 and the second housing described above may be used.

  The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims. For example, the pin member 309 may be a copper member in which a resin is embedded. Further, any one of the positioning members 318 and 319 may be eliminated. Since the power board 78 runs along the first wall 101 of the first housing 23, the positioning of the power board 78 can be performed with a single positioning member with high accuracy. Further, if a positioning member having a polygonal cross section is used, it is possible to prevent the power board 78 from rotating around the positioning member even with a single positioning member.

In the above-described embodiment, an example in which the present invention is applied to a so-called column assist type electric power steering apparatus has been described. The present invention may be applied to a power steering device.
In the above-described embodiment, the example in which the present invention is applied to the electric power steering apparatus that outputs the output of the electric motor as the steering assist force has been described, but the present invention is not limited thereto. For example, a transmission ratio variable mechanism that includes a transmission ratio variable mechanism capable of changing a ratio of a steered wheel turning angle to a steering angle of a steering member, and that uses an output of an electric motor to drive the transmission ratio variable mechanism, is used for vehicle steering. Even if the present invention is applied to a device, a steer-by-wire type vehicle steering device in which the mechanical connection between the steering member and the steered wheel is released and the steered wheel is steered by the output of the electric motor, etc. Good.

Further, at least a part of the power board 78 and the control board 79 of the ECU 12 may be molded with resin.
In the above-described embodiment, an example in which a brushless motor is used as the electric motor 18 has been described. However, the invention is not limited thereto, and a motor other than the brushless motor may be used as the electric motor 18.

It is a mimetic diagram showing a schematic structure of an electric power steering device as a vehicle steering device concerning one embodiment of the present invention. It is a schematic perspective view of a steering assist mechanism. FIG. 3 is a schematic perspective view of the steering assist mechanism when the steering assist mechanism is viewed from an angle different from that of FIG. 2. It is an illustration sectional view of a steering auxiliary mechanism cut along the axial direction of an electric motor. It is a disassembled perspective view of the 1st housing and the components of ECU accommodated in this. It is an enlarged view of the principal part of FIG. It is a typical top view of a power board. It is sectional drawing of the principal part which shows the state by which the power board was fixed to the thick part of the 1st housing. It is sectional drawing of the principal part along the IX-IX line of FIG. It is sectional drawing of the principal part for demonstrating manufacture of a board | substrate unit, (A) has shown the punching process, (B) has shown the coating process, (C) has carried out the punching process. Show. It is sectional drawing of the principal part for demonstrating manufacture of a board | substrate unit, (A) has shown the press injection process of the pin member, (B) has shown the plating process. It is sectional drawing of the principal part for demonstrating manufacture of a board | substrate unit, (A) has shown the process of fixing a metal base to a board | substrate body, (B) has shown the process of applying oxygen plasma. , (C) shows a step of applying hydrogen plasma. It is sectional drawing of the principal part for demonstrating manufacture of a board | substrate unit, (A) has shown the process of mounting an electronic component, (B) has shown the solder reflow process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus (steering apparatus for vehicles), 4 ... Steering mechanism, 18 ... Electric motor, 77a ... Thick part (board | substrate installation member), 78 ... Power board (laminated circuit board, motor control apparatus), 82 ... Motor drive circuit, 83... FET (motor drive element), 301... Substrate body, 301 a... (Surface of substrate body), 301 b... (Back surface of substrate body), 301 c. Base, 304 ... Cover member, 308 ... Via hole, 311, 313, 315, 317 ... Insulating layer, 312, 314, 316 ... Layer including conductor, 312a, 312c, 314a, 316a, 316b, 316d ... Conductive part (conductor) 318, 319 ... positioning members, 321a, 321b ... first positioning holes, 326 ... joints, D ... stacking direction.

Claims (6)

A substrate body formed by laminating a layer including a conductor and an insulating layer;
A covering member,
The substrate body includes a front surface and a back surface facing the stacking direction, and a side surface,
The laminated circuit board, wherein the side surface is covered with the covering member.   2. The laminated circuit board according to claim 1, wherein the insulating layer includes a base material and a heat conductive material having a higher thermal conductivity than the base material. In Claim 1 or 2, the substrate body is provided with a via hole,
The surface of the substrate body includes a bonding portion for bonding by wire bonding,
The laminated circuit board is arranged such that the joining portion avoids the via hole in the lamination direction. In any one of Claims 1-3, the said laminated circuit board is equipped with the metal base joined to the back surface of a board | substrate body, and the positioning hole formed in this metal base,
A laminated circuit board capable of fitting a positioning member formed on a board installation member on which the metal base is installed into the positioning hole. The laminated circuit board according to any one of claims 1 to 4,
A motor control device comprising: a motor drive circuit including a motor drive element mounted on the board body of the multilayer circuit board. A motor control device according to claim 5;
A vehicle steering apparatus comprising: an electric motor that is driven by the motor control apparatus and applies a steering force to a steering mechanism.

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