JP5787131B2 - Electric motor unit - Google Patents

Description

  The present invention relates to an electric motor unit.

  For example, an electric motor unit provided in an electric power steering apparatus includes a stator coil. When electric power is supplied to this coil, the rotor of the electric motor rotates. The output of the rotor is transmitted to the steering shaft via a speed reduction mechanism or the like, and becomes a steering assist force that assists the driver's steering.

JP 2009-188123 A

Electric power is supplied to the coil from the drive circuit board via a bus bar. Since the electric power steering apparatus needs to be arranged in a narrow space in the vehicle compartment or the engine room, the bus bar needs to be made as compact as possible.
However, in order to generate a sufficient steering torque, it is necessary to pass a large current through the coil. For this reason, it is necessary to make the bus bar thick, and it is difficult to reduce the size of the structure around the electric motor. In addition, since a large current flows through the bus bar and the coil, the power loss increases. Moreover, since the drive circuit board includes a switching element as a heat generating element, high heat dissipation performance is required for the electric motor unit.

  The present invention has been made under such a background, and an object of the present invention is to provide an electric motor unit that can reduce power loss, achieve miniaturization, and is excellent in heat dissipation performance.

To achieve the above object, the present invention provides an electric motor (18) including a first coil (54) and a second coil (55), and a first power circuit (75) for supplying electric power to the first coil. ) And a second power circuit (80) for supplying electric power to the second coil and formed using a member different from the first power substrate. The second power board (32) is disposed adjacent to the first and second coils with respect to the axial direction (X1) of the electric motor and surrounding the central axis (L1) of the electric motor. a housing (23) for accommodating the first and second power board, a plurality of conductive members (711U, 711V, 711W, 712U , 712V, 712W) and coupled to each other these conductive members within said housing A first motor bus bar unit including a first coupling portion (73U, 73V, 73W), wherein the first coil and the first power circuit are held by a resin holding member (63) on the first coil. 56) and a plurality of conductive members (723U, 723V, 723W, 724U, 724V, 724W) and these conductive members in the housing. The second motor bus bar includes a second coupling portion (74U, 74V, 74W) coupled to each other, and the second coil and the second power circuit are held on the first coil by a resin holding member. Second bus bars (72U, 72V, 72W) for electrical connection via a unit (58), and when viewed from the axial direction of the central axis, the first and first The coupling portion is arranged point-symmetrically with respect to the central axis and is separated from each other, and the first and second bus bars are arranged point-symmetrically with respect to the central axis as seen from the axial direction of the central axis. The first and second coils have a reference thickness intersecting with the central axis line when viewed from the axial direction of the central axis line so that the wiring thicknesses are equal to each other and the wiring lengths are equal to each other. The first and second power boards are arranged along the flat inner bottom surface (41a) of the housing when viewed from the axial direction of the central axis, and are arranged symmetrically about the axis (L2). The first and second power board outer portions (31a, 32a) are disposed so as to be opposed to each other across a reference axis that intersects the central axis, and viewed from the axial direction of the central axis. The center An electric motor unit (33) is provided that is arranged symmetrically with respect to an axis, and arranged symmetrically with respect to the reference axis (claim 1).

  According to the present invention, the electric motor can be driven by flowing the current from the first power circuit through the first coil and flowing the current from the second power circuit through the second coil. Thereby, since the electric current sent through each coil can be decreased, the power loss in each coil can be decreased. As a result, the power loss of the entire electric motor can be reduced. Moreover, since it is possible to supply power to both the first and second coils at the same time, the maximum output of the electric motor is sufficiently large even if the current flowing through each coil is small (even if the power loss is small). it can. In addition, since the current flowing through each coil can be reduced, each power circuit can be made smaller and each coil can be made thinner. As a result, the electric motor unit can be downsized. In addition, as a result of housing each power board in a housing arranged coaxially with the electric motor, the space around the electric motor can be used effectively, so that the electric motor unit can be further miniaturized. Moreover, when viewed from the axial direction of the electric motor, the power boards are arranged apart from each other, whereby heat from each power board can be efficiently transmitted to other members such as a housing. Thereby, the heat dissipation performance of the electric motor unit can be further increased.

Further, when viewed from the axial direction before Symbol central axis, said first power substrate and the second power substrate across the reference line (L2) intersecting the central axis is disposed.
With such an arrangement, the first power board and the second power board can be spaced apart when viewed in the axial direction.

Further, when viewed from the axial direction of the central axis, the outer portion (31a) of the first power board and the outer portion (32a) of the second power board are arranged symmetrically with respect to the central axis. been, that have been and are disposed in line symmetry about said reference straight line.
That is, the outer portion of the first power board and the outer portion of the second power board are arranged point-symmetrically and line-symmetrically. Thereby, two power boards can be arrange | positioned so that the center axis line of an electric motor may be enclosed. Therefore, the amount of the two power boards protruding in the radial direction of the electric motor can be reduced, and further miniaturization of the electric motor unit can be realized. Further, when each power substrate is formed by punching from a plate-like material, the number of power substrates that can be punched from a plate material having a certain size can be increased. Thereby, the first power substrate and the second power substrate can be efficiently formed from one material.

In addition, since the first bus bar is formed by combining the plurality of conductive members formed separately at the first connecting portion, the degree of freedom of the shape of each conductive member can be increased. As a result, the first bus bar can be compactly arranged in the housing while avoiding contact with other components. Thereby, further miniaturization of the electric motor unit can be realized.
Similarly to the first bus bar, the plurality of conductive members formed separately are joined at the second coupling portion to form the second bus bar, so that the degree of freedom of the shape of each conductive member can be increased. As a result, the second bus bar can be compactly arranged in the housing while avoiding contact with other components. Thereby, further miniaturization of the electric motor unit can be realized.
In the present invention, the first and second bus bars, the first and second power boards, a control board on which a control circuit for controlling driving of the first and second power circuits is formed, There may be a case where a sub-assembly is configured in which a connection line connecting the power circuit and the control circuit is held by a module including a resin member (claim 2).

Further, in the present invention, when viewed from the axial direction of the central axis, the first and second power substrates are along the second direction (D2) intersecting the first direction (D1) facing each other. In some cases, the first and second coupling portions are opposed to each other, and the first and second coupling portions are arranged so as to be exposed to openings (101, 102, 103) formed in the housing (claims). Item 3 ).
In this case, the first power substrate, the second power substrate, the first coupling portion, and the second coupling portion can be efficiently arranged. Thereby, since the dead space in a housing can be reduced, the further size reduction of an electric motor unit is realizable.

In addition, the first and second coupling portions are arranged so as to be exposed to the openings (101, 102, 103) formed in the housing, and thus have the following advantages.
That is , the exterior of the housing and the first coupling portion, and the exterior of the housing and the second coupling portion are not blocked by the components in the housing, respectively. Thereby, the tool (for example, welding tool) which couple | bonds the electrically-conductive members of a 1st bus-bar can be easily inserted in a housing through an opening part. Thereby, the effort concerning the assembly of the electric motor unit can be reduced.

Further, in the present invention, the control circuit (99) is a control board that is formed is disposed within said housing (35), said second and said first coupling section for controlling the driving of the first and second power circuits There may be a case where it is arranged between the connecting portions (claim 4 ).
In this case, the first coupling portion and the second coupling portion are disposed outside the control board. Therefore, it is easy to perform the operation of joining the conductive members of the first bus bar to form the first coupling portion or the operation of joining the conductive members of the second bus bar to form the second coupling portion.

In the present invention, the housing includes a peripheral wall (42) surrounding the first and second coupling portions, and the openings (102, 103) are formed by cutting out a part of the peripheral wall. (Claim 5 ).
In this case, by forming the tool into the housing from the opening of the peripheral wall, it is possible to easily form each coupling portion.

  In addition, in the above, the 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.

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 the side view which fractured and showed a part of principal part of an electric power steering device. It is the perspective view which decomposed | disassembled the principal part of the electric motor unit, and has shown the state from which the 1st housing and the motor housing main body were isolate | separated. It is the perspective view which decomposed | disassembled the principal part of the electric motor unit, and has shown the state with which the 1st housing and the motor housing main body were couple | bonded. It is sectional drawing which cut | disconnected the principal part of the stator in the direction orthogonal to an axial direction. It is a typical top view when a part of ECU is seen from an axial direction. (A) is a typical fragmentary sectional view for demonstrating the principal point regarding manufacture of an electric motor unit, (B) is a top view for demonstrating welding work. It is a figure which shows the principal part of another embodiment of this invention.

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 includes a steering wheel 2 as a steering member, a steering mechanism 4 that steers a steered wheel 3 in conjunction with rotation of the steering wheel 2, and steering of a driver. And a steering assist mechanism 5 for assisting. The steering wheel 2 and the steering mechanism 4 are mechanically coupled via a steering shaft 6 and an intermediate shaft 7.

In the present embodiment, a description will be given based on an example in which the steering assist mechanism 5 applies assist force (steering assist force) to the steering shaft 6. However, the present invention can also be applied to a structure in which the steering assist mechanism 5 applies an assist force to a pinion shaft described later, or a structure in which the steering assist mechanism 5 applies an assist force to a rack shaft described later.
The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the 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.

  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 (Electronic Control Unit) 12 as a control device. Further, the vehicle speed detection result from the vehicle speed sensor 30 is input to the ECU 12. The intermediate shaft 7 connects the steering shaft 6 and the steering mechanism 4.

The steered mechanism 4 includes a pinion shaft 13 and a rack and pinion mechanism including 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 provided at the tip (lower end in FIG. 1) of the pinion shaft 13.

  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 an electric motor 18 for assisting steering, 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. The speed reduction mechanism 19 includes a worm shaft 20 as a drive gear and a worm wheel 21 as a driven gear that meshes with the worm shaft 20. The speed reduction mechanism 19 is accommodated in the gear housing 22.

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 integrally rotatable.
When the electric motor 18 rotationally drives the worm shaft 20, the worm wheel 21 is rotationally driven by the worm shaft 20. Thereby, the worm wheel 21 and the steering shaft 6 rotate integrally. 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 30, 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.

  FIG. 2 is a side view in which a part of the main part of the electric power steering apparatus 1 is cut away. FIG. 3 is an exploded perspective view of the main part of the electric motor unit 33 of the electric power steering apparatus 1 and shows a state where the first housing 23 and the motor housing body 27 are separated. FIG. 4 is an exploded perspective view of the main part of the electric motor unit 33. FIG. 4 shows a state where the first housing 23 and the motor housing body 27 are coupled, and a state where the subassembly 98 is separated from the first housing 23.

  Referring to FIG. 2, electric motor unit 33 is formed by ECU 12 and electric motor 18. The ECU 12 includes a first housing 23 as an ECU housing, a first power board 31 and a second power board 32, a module 34, a control board 35, and a rotational position sensor 36. The first housing 23 accommodates and holds the first power board 31, the second power board 32, the module 34, the control board 35, and the rotational position sensor 36.

The first housing 23 is in contact with the second housing 24. The second housing 24 is provided as a lid that closes the second housing 24.
The first housing 23 and the second housing 24 are each formed in a substantially cylindrical shape with one end opened. The ends of the first and second housings 23 and 24 are abutted and fastened to each other by a fixing screw 25.

The electric motor 18 includes a motor housing 26, a rotating shaft 40, a rotor 51, and a stator 52. The motor housing 26 includes a cylindrical motor housing body 27 and the first housing 23 described above. The motor housing body 27 is fixed to the first housing 23 using a screw member (not shown).
The gear housing 22 includes a cylindrical drive gear housing 28 that houses the worm shaft 20, a tubular driven gear housing 29 that houses the worm wheel 21, and the second housing 24. Has been.

  With reference to FIG. 4, the first housing 23 is disposed so as to surround a central axis L <b> 1 (hereinafter also simply referred to as a central axis L <b> 1) of the rotating shaft 40 of the electric motor 18. The first housing 23 includes a bottom wall 41 and a peripheral wall 42. The bottom wall 41 is disposed so as to be orthogonal to the axial direction X1 of the rotating shaft 40 (hereinafter also simply referred to as the axial direction X1). The bottom wall 41 has a function as a heat sink, and heat from each of the power boards 31 and 32 that are in contact with the bottom wall 41 can be efficiently discharged to the outside of the first housing 24. Of the bottom wall 41, a bottom surface 41a facing the inside of the first housing 23 is formed flat. In addition, you may improve the thermal radiation performance of the bottom wall 41 by increasing the thickness of some bottom walls 41 rather than another part.

A rotation shaft insertion hole 41 b for the electric motor 18 is formed in the center of the bottom wall 41. The bottom wall 41 has a first bus bar insertion hole 41c and a second bus bar insertion hole 41d.
The peripheral wall 42 extends from the outer peripheral portion of the bottom wall 41 toward one X11 side (second housing 24 side) in the axial direction X1, and is formed in an annular shape surrounding the ECU chamber 37. In the present embodiment, the peripheral wall 42 is formed in an annular shape. An ECU chamber 37 is formed by the peripheral wall 42 and the bottom wall 41.

  With reference to FIG. 2, the rotating shaft 40 of the electric motor 18 is inserted through the inside of the motor housing body 27 and through the first housing 23. The rotating shaft 40 extends into the first housing 23 through the rotating shaft insertion hole 41b. The first housing 23 is adjacent to first and second coils 54 and 55, which will be described later, in the axial direction X1. The rotary shaft 40 and the worm shaft 20 are arranged side by side on the same axis, and both are connected via a joint 39 so that power can be transmitted.

The worm shaft 20 is supported at both ends by the drive gear housing 28 via the first bearing 46 and the second bearing 47. The rotary shaft 40 is rotatably supported by a third bearing 48 held on the bottom wall 41 of the first housing 23 and a fourth bearing 49 held on the motor housing body 27.
In the present embodiment, a brushless motor is used as the electric motor 18. A rotor 51 and a stator 52 are accommodated in the motor housing 26. The rotor 51 is connected to the rotary shaft 40 so as to be rotatable together. The rotor 51 is surrounded by the stator 52.

The stator 52 is fixed to the inner periphery of the motor housing body 27. Stator 52 includes a stator core 53, a first coil 54, and a second coil 55.
The stator core 53 includes an annular yoke 50 and a plurality of teeth 53 protruding radially inward from the inner periphery of the yoke 50. The yoke 50 is fixed to the inner peripheral surface of the motor housing body 27 by shrink fitting or the like. FIG. 5 is a cross-sectional view of the main part of the stator 52 cut in a direction orthogonal to the axial direction X1. Referring to FIG. 5, a plurality of teeth 53 are arranged at equal intervals in the circumferential direction C1.

The first coil 54 and the second coil 55 are formed using different members and are controlled independently. The first and second coils 54 and 55 are wound around the teeth 53, respectively. When viewed from the axial direction X <b> 1, the entire first coil 54 and the entire second coil 55 are arranged symmetrically about the central axis L <b> 1 of the electric motor 18.
Further, when viewed from the axial direction X1, the entire first coil 54 and the entire second coil 55 are arranged symmetrically about a reference straight line L2 passing through the central axis L1 of the electric motor 18. . Specifically, for example, when viewed from the axial direction X1, the first coil 54 is disposed on one side of the reference straight line L2 (upper side in FIG. 5), and the other side of the reference straight line L2 (in FIG. 5). A second coil 55 is disposed on the lower side. With the above configuration, the length and thickness of the wiring of the first coil 54 and the wiring and thickness of the wiring of the second coil 55 can be made as equal as possible.

Thereby, the impedance in the 1st coil 54 and the impedance in the 2nd coil 55 are substantially equalized. In addition, arrangement | positioning of the 1st coil 54 and the 2nd coil 55 is an example, and is not limited to said aspect.
First coil 54 includes a U-phase coil, a V-phase coil, and a W-phase coil. Second coil 55 includes a U-phase coil, a V-phase coil, and a W-phase coil.

Referring to FIG. 2, the first coil 54 is configured to be supplied with power from the first power board 31. The first coil 54 and the first power board 31 are electrically connected via the first motor bus bar unit 56 and the first bus bars 71U, 71V, 71W.
The second coil 55 is configured to be supplied with power from the second power board 32. The second coil 55 and the second power board 32 are electrically connected through the second motor bus bar unit 58 and the second bus bars 72U, 72V, 72W.

The first and second motor bus bar units 56 and 58 are accommodated in a motor chamber 38 defined by the motor housing body 27 and the first housing 23, respectively.
The first motor bus bar unit 56 is coupled to the first coil 54. Second motor bus bar unit 58 is coupled to second coil 55.
The first and second motor bus bar units 56 and 58 are held by an annular holding member 63 made of synthetic resin. The holding member 63 is held by the first and second coils 54 and 55 and the like.

FIG. 6 is a schematic plan view when a part of the ECU 12 is viewed from the axial direction X1. FIG. 6 shows a state where the control board 35 is removed. 2 and 6, first bus bars 71U, 71V, 71W are used to electrically connect first coil 54 and first power circuit 75 formed on first power board 31. Is provided.
In addition, since the structure of the 1st bus-bar 71U, 71V, 71W is the same, below, the 1st bus-bar 71U is mainly demonstrated below.

The first bus bar 71U is formed by coupling a plurality of conductive wires (conductive members) such as copper wires.
The first bus bar 71U includes first and second conductive members 711U and 712U as a plurality of conductive members. First conductive member 711U is coupled to first motor bus bar unit 56 so as to be conductive by welding or the like. Referring to FIGS. 4 and 6, first conductive member 711 </ b> U is inserted through bus bar insertion hole 41 c in bottom wall 41. One end 711bU of the first conductive member 711U extends in parallel with the axial direction X1 in the ECU chamber 37 and is adjacent to the peripheral wall 42. That is, one end portion 711 b U of the first conductive member 711 U is disposed at the outer end portion of the ECU chamber 37 with respect to the radial direction R 1 of the electric motor 18 (hereinafter also simply referred to as the radial direction R 1).

  With reference to FIG. 6, the second conductive member 712 </ b> U is disposed in the ECU chamber 37 and constitutes a part of the module 34. One end 712bU of the second conductive member 712U extends in parallel with the axial direction X1, and is adjacent to the one end 711bU of the first conductive member 711U. These one end portions 711bU and 712bU are coupled so as to be conductive by welding or the like, and constitute a first coupling portion 73U. The other end of the second conductive member 712U is disposed in the vicinity of the first power board 31 and is electrically connected to the first power circuit 75 formed on the first power board 31 via the first bonding wire 64. It is connected to the.

  Similar to the first bus bar 71U, the first bus bar 71V includes first and second conductive members 711V and 712V. One end 711bV of the first conductive member 711V and one end 712bV of the second conductive member 712V are coupled so as to be conductive by welding or the like. A first coupling portion 73V is formed by the one end portions 711bV and 712bV. The other end of the second conductive member 712V is electrically connected to the first power circuit 75 via the first bonding wire 64.

  Similarly to the first bus bar 71U, the first bus bar 71W includes first and second conductive members 711W and 712W. One end 711bW of the first conductive member 711W is coupled to the one end 712bW of the second conductive member 712W so as to be conductive by welding or the like. A first coupling portion 73W is formed by the one end portions 711bW and 712bW. The other end of the second conductive member 712 </ b> W is electrically connected to the first power circuit 75 via the first bonding wire 64.

2 and 6, second bus bars 72U, 72V, 72W are used to electrically connect second coil 55 and second power circuit 80 formed on second power board 32. Is provided. In addition, since the structure of 2nd bus-bar 72U, 72V, 72W is the same, below, 2nd bus-bar 72U is mainly demonstrated below.
Similar to the first bus bar 71U, the second bus bar 72U is formed by coupling a plurality of conductive wires (conductive members) such as copper wires.

  The second bus bar 72U includes third and fourth conductive members 723U and 724U as a plurality of conductive members. Third conductive member 723U is coupled to second bus bar unit 58 so as to be conductive by welding or the like. Referring to FIGS. 4 and 6, third conductive member 723 </ b> U is inserted through bus bar insertion hole 41 d of bottom wall 41. One end portion 723bU of the third conductive member 723U extends in parallel with the axial direction X1 in the ECU chamber 37 and is adjacent to the peripheral wall 42. That is, the one end 723bU of the third conductive member 723U is disposed at the outer end of the ECU chamber 37 with respect to the radial direction R1.

  With reference to FIG. 6, the fourth conductive member 724 </ b> U is disposed in the ECU chamber 37 and constitutes a part of the module 34. One end 724bU of the fourth conductive member 724U extends parallel to the axial direction X1, and is adjacent to the one end 723bU of the third conductive member 723U. These one end portions 723bU and 724bU are coupled so as to be conductive by welding or the like, and constitute a second coupling portion 74U. The other end of the fourth conductive member 724U is disposed in the vicinity of the second power board 32, and is electrically connected to the second power circuit 80 formed on the second power board 32 via the second bonding wire 65. It is connected to the.

  Similar to the second bus bar 72U, the second bus bar 72V includes third and fourth conductive members 723V and 724V. The one end 723bV of the third conductive member 723V and the one end 724bV of the fourth conductive member 724V are coupled so as to be conductive by welding or the like. A second coupling portion 74V is formed by the one end portions 723bV and 724bV. The other end of the fourth conductive member 724 is electrically connected to the second power circuit 80 via the second bonding wire 65.

  Similarly to the second bus bar 72U, the second bus bar 72W includes third and fourth conductive members 723W and 724W. One end 723bW of the third conductive member 723W is coupled to the one end 724bW of the fourth conductive member 724W so as to be conductive by welding or the like. A second coupling portion 74W is formed by the one end portions 724bW and 724bW. The other end of the fourth conductive member 724 </ b> W is electrically connected to the second power circuit 80 via the second bonding wire 65.

The first bus bars 71U, 71V, 71W and the second bus bars 72U, 72V, 72W are arranged symmetrically with respect to the central axis L1 (center point) of the electric motor 18 when viewed from the axial direction X1. .
Further, when viewed from the axial direction X1, the first coupling portions 73U, 73V, and 73W and the second coupling portions 74U, 74V, and 74W are disposed symmetrically with respect to the central axis L1 of the electric motor 18. .

Here, when viewed from the axial direction X1, the direction in which the first power substrate 31 and the second power substrate 32 face each other is defined as a first direction D1. Further, when viewed from the axial direction X1, the direction in which the first coupling portions 73U, 73V, 73W and the second coupling portions 74U, 74V, 74W face each other is defined as a second direction D2.
When viewed from the axial direction X1, the first direction D1 and the second direction D2 intersect (orthogonal). The first coupling parts 73U, 73V, 73W, the first power board 31, the second coupling parts 74U, 74V, 74W, and the second power board 32 are arranged side by side in the circumferential direction C1.

2 and 6, the first power board 31 is disposed on the bottom wall 41 of the first housing 23 and is in contact with the bottom wall 41. In the present embodiment, the first power substrate 31 is a multilayer circuit substrate in which insulating layers and conductive layers are alternately stacked. The first power substrate 31 may be a single layer circuit substrate having one insulating layer.
When viewed from the axial direction X1, the first power substrate 31 is formed in a curved shape. More specifically, the first power board 31 is formed in a shape (in the present embodiment, an arc shape) obtained by cutting a part of an annular plate centering on the central axis L <b> 1 of the electric motor 18. When viewed from the axial direction X1, the outer portion 31a of the first power board 31 includes an inner diameter portion 31b, an outer diameter portion 31c, one end portion 31d, and the other end portion 31e. When viewed from the axial direction X1, the inner diameter portion 31b and the outer diameter portion 31c each have an arc shape. More specifically, when viewed from the axial direction X1, the inner diameter portion 31b and the outer diameter portion 31c are inferior arcs, respectively. In the present embodiment, the range in which the inner diameter portion 31b and the outer diameter portion 31c are provided is about 45 ° around the central axis L1. Each of the one end 31d and the other end 31e extends along the radial direction R1.

  A first power circuit 75 is formed on the first power substrate 31. The first power circuit 75 is provided to supply power to the first coil 54. The first power circuit 75 includes six first FETs 76 as switching elements. The first FET 76 is mounted on the first power substrate 31. The first power circuit 75 includes a bridge circuit using the first FET 76 and a current detection circuit. The first power circuit 75 includes first terminals 77U, 77V, 77W and power supply terminals 78, 79. These five terminals 77U, 77V, 77W, 78, 79 are connected to the first power board 31. It arrange | positions adjacent to the outer shell part 31a. A first bonding wire 64 is bonded to each of the first terminals 77U, 77V, and 77W.

  The second power board 32 is disposed on the bottom wall 41 of the first housing 23 and is in contact with the bottom wall 41. The second power board 32 is formed using a member different from the first power board 31. In the present embodiment, the second power board 32 is a circuit board (for example, a multilayer circuit board) similar to the first power board 31. When viewed from the axial direction X1, the first power board 31 and the second power board 32 are arranged across the reference straight line L2, and are separated from each other. When viewed from the axial direction X1, the reference axis L2 is a straight line that intersects the central axis L1, and extends along the second direction D2.

  When viewed from the axial direction X1, the second power substrate 32 and the first power substrate 31 are arranged symmetrically with respect to the central axis L1, and when viewed from the axial direction X1, The outer portion 31a of the first power board 31 and the outer portion 32a of the second power board 32 are arranged point-symmetrically around the central axis L1 and are arranged symmetrically about the reference straight line L2. . The first power board 31 and the second power board 32 are opposed to each other across the central axis L1.

  A second power circuit 80 is formed on the second power substrate 32. The second power circuit 80 is provided to supply power to the second coil 55. The second power circuit 80 is configured to be operable independently of the first power circuit 75. Thereby, it is possible to supply power to the first coil 54 and the second coil 55 independently, and to link the power supply to the first coil 54 and the power supply to the second coil 55. Is possible.

When viewed from the axial direction X1, the first power circuit 75 and the second power circuit 80 are arranged symmetrically with respect to the central axis L1. As described above, the first and second power substrates 31 and 32 are arranged point-symmetrically, and the first and second power circuits 75 and 80 are arranged point-symmetrically.
That is, the first power board 31 and the first power circuit 75 have the same configuration as that of the second power board 32 and the second power circuit 80, respectively, and common parts are realized. The second power circuit 80 includes six second FETs 81 as switching elements. The second power circuit 80 includes a bridge circuit using the second FET 81 and a current detection circuit. The second power circuit 80 includes second terminals 82U, 82V, 82W and power supply terminals 83, 84. A second bonding wire 65 is coupled to each of the second terminals 82U, 82V, and 82W.

The module 34 is provided to transmit power from a vehicle battery (not shown) to the power circuits 75 and 80. The module 34 is provided to transmit the electric power from the first and second power circuits 75 and 80 to the first and second coils 54 and 55, respectively.
The module 34 has a structure in which various electric elements are collectively held by resin. As a result, a plurality of electric elements can be assembled to the first housing 23 in a lump, so that the labor required for assembling each electric element into the first housing 23 can be reduced.

The module 34 includes a resin member 85, second conductive members 712U, 712V, and 712W, fourth conductive members 724U, 724V, and 724W, power bus bars 86 and 87, capacitors 88 and 89, coils 90, and a relay 91. And.
The resin member 85 is an insulating member made of synthetic resin. The resin member 85 is disposed on the bottom wall 41 of the first housing 23. The resin member 85 is fixed to the bottom wall 41 using a screw member, a claw member, or the like (not shown).

  The resin member 85 includes a base 92 received by the bottom wall 41 and a plurality of protrusions 93 protruding from the base 92. The rotating shaft 40 of the electric motor 18 is inserted through the insertion hole 92c formed at the center of the base 92. Further, the base 92 is formed with a first frame portion 92a and a second frame portion 92b. The first and second frame portions 92a and 92b are each formed by penetrating the base 92 in the axial direction X1. When viewed from the axial direction X1, the shapes of the inner peripheral surfaces of the first and second frame portions 92a and 92b are the shapes of the outer portion 31a of the first power substrate 31 and the outer portion 32a of the second power substrate 32, respectively. It matches. First and second power boards 32 are fitted into the first and second frame portions 92a and 92b, respectively, and these power boards 31 and 32 are fixed by screw members and claw members (not shown). .

The protrusions 93 are provided to hold the control board 35, and a plurality (for example, four) of the protrusions 93 are arranged apart from each other in the circumferential direction C1. Referring to FIGS. 4 and 6, first recesses 94 are formed on the inner surface of each protrusion 93. Each first recess 94 is formed corresponding to the outer shape of the control board 35.
Two second recesses 95 and 95 are formed in the resin member 85. The 2nd recessed parts 95 and 95 are formed in the both ends of the base 92 regarding the 2nd direction D2. Each of the second recesses 95, 95 has a shape in which the base 92 is recessed inward in the radial direction R1. In the second recesses 95, 95, first coupling portions 73U, 73V, 73W and second coupling portions 74U, 74V, 74W are arranged, respectively.

The base 92 embeds and holds most of the second conductive members 712U, 712V, 712W and most of the fourth conductive members 724U, 724V, 724W.
Referring to FIG. 6, power bus bars 86 and 87 are formed by press-molding a metal plate. The first end portions 86 a and 87 a of the power bus bars 86 and 87 are exposed on the outer peripheral surface side of the base 92. These first end portions 86a and 87a are configured to be electrically connected to a positive electrode and a negative electrode of a battery (not shown).

  Intermediate portions of the power bus bars 86 and 87 are embedded in the resin member 85. Thus, the power bus bars 86 and 87 are held by the resin member 85. Further, intermediate portions of the power bus bars 86 and 87 are electrically connected to the corresponding capacitors 88 and 89, the coil 90 and the relay 91. Thereby, the ripple of the current of each power circuit 75 and 80 can be suppressed, and the current of each power circuit 75 and 80 can be cut off at the time of failure. The power bus bar 86 is branched into two on the way, and includes a second end 86b and a third end 86c. The power bus bar 87 is branched into two on the way and includes a second end 87b and a third end 87c. The second end 86b of the power bus bar 86 and the second end 87b of the power bus bar 87 are electrically connected to the power terminals 78 and 79 of the first power circuit 75 via the third bonding wires 66, respectively. Yes. The third end 86 c of the power bus bar 86 and the third end 87 c of the power bus bar 87 are electrically connected to the power terminals 83 and 84 of the second power circuit 80 via the fourth bonding wires 67, respectively. Yes.

Referring to FIGS. 2 and 6, with the above-described configuration, the current from the battery of the vehicle generates power bus bars 86, 87, first power circuit 75, first bus bars 71U, 71V, 71W, and first motor bus bar unit. It flows to the first coil 54 via 56.
Similarly, the current from the vehicle battery flows to the second coil 55 via the power bus bars 86 and 87, the second power circuit 80, the second bus bars 72 U, 72 V and 72 W, and the second motor bus bar unit 58.

  As shown in FIGS. 3 and 4, the control board 35 is arranged to be separated from the power boards 31 and 32 in the axial direction X1. The control board 35 is formed using a circuit board (for example, a multilayer circuit board) similar to the power board 31. The control board 35 includes a rectangular first portion 35a extending in the first direction D1, and a second portion 35b protruding from the first portion 35a in the second direction D2. Two screw insertion holes 35d are formed in the first portion 35a. The control board 35 is fixed to the base 92 by fixing the screw member 97 that passes through the screw insertion holes 35 d to the base 92.

  In addition to the power boards 31 and 32, the control board 35 is fixed to the resin member 85 of the module 34. As a result, a subassembly 98 is formed in which the module 34, the power boards 31 and 32, and the control board 35 are assembled together. Since the subassembly 98 can be assembled to the first housing 23 in a lump, the labor for assembling the electric motor unit 33 can be significantly reduced.

Both end portions of the first portion 35 a in the first direction D <b> 1 are fitted in a pair of holding recesses 23 a formed in the first housing 23.
The second portion 35b protrudes along the second direction D2 from both ends of the first portion 35a with respect to the second direction D2. Each second portion 35 b is received by the first recess 94 of the corresponding protrusion 93 of the resin member 85.

  A control circuit 99 is formed on the control board 35. The control circuit 99 is provided to control the driving of the first power circuit 75 and the second power circuit 80, respectively. The control circuit 92 includes a driver that controls the power circuits 75 and 80 and a CPU that controls the driver. The control board 35 is configured to receive a control signal from the torque sensor 11 (see FIG. 1) or the like. The control circuit 99 and the power circuits 75 and 80 are electrically connected via a connection line 100 extending in parallel with the axial direction X1. The control board 35 is disposed between the first coupling portions 73U, 73V, and 73W and the second coupling portions 74U, 74V, and 74W in the second direction D2.

4 and 6, the first and coupling portions 73U, 73V, 73W, 74U, 74V, 74W are exposed to the first opening 101 of the first housing 23 when viewed from the axial direction X1. ing. The first opening 101 faces one X11 side (upper side in FIG. 4) in the axial direction X1.
Further, the second opening 102 and the third opening 103 are formed by cutting out a part of the peripheral wall 42. The second opening 102 is disposed adjacent to the first coupling portions 73U, 73V, and 73W and the second direction D2 (radial direction R1). The first coupling portions 73U, 73V, and 73W are exposed from the second opening 102 to the outside of the first housing 23. A lid 104 that closes the second opening 102 is attached to the second opening 102.

  The third opening 103 is disposed adjacent to the second coupling portions 74U, 74V, 74W and the second direction D2 (radial direction R1). The second coupling portions 74U, 74V, and 74W are exposed to the outside of the first housing 23 from the third opening 103. A lid 105 that closes the third opening 103 is attached to the third opening 103. The third opening 103 and the second opening 102 are opposed to each other in the second direction D2.

With the above configuration, when the lid 104 is removed, the welding tool for the first coupling portions 73U, 73V, 73W can be inserted into the ECU chamber 37 through the second opening 102. Similarly, when the lid 105 is removed, a tool for welding the second coupling portions 74U, 74V, and 74W can be inserted into the ECU chamber 37 through the third opening 103.
Next, the main points of assembly of the electric motor unit 33 will be described.

  As shown in FIG. 7A, a material 110 made of a rectangular printed wiring board material is pressed with a punch 111. Thereby, the first power substrate 31 and the second power substrate 32 are formed. In FIG. 7A, the power substrates 31 and 32 are shown as being punched from the material 110. At this time, as a result of the power substrates 31 and 32 being formed in an arc shape of less than 180 °, the number of power substrates that can be taken out from one material 110 is increased. Next, power circuits 75 and 80 are formed by mounting FETs 76 and 81 (not shown) on the power substrates 31 and 32, respectively.

  Next, as shown in FIG. 4, a module 34, power boards 31 and 32, and a control board 35 are prepared. Then, the power boards 31 and 32 are assembled to the resin member 85 of the module 34, and the control board 35 is fixed to the resin member 85 to assemble the subassembly 98. The first and second power circuits 75 and 80 and the control circuit 99 are electrically connected via the connection line 100. Next, a continuity test between the power circuits 75 and 80 and the control circuit 99 is performed using an inspection device (not shown).

Next, in the first housing 23 in a state in which the one end portions 711bU, 711bV, 711bW of the first conductive members 711U, 711V, 711W and the one end portions 723bU, 723bV, 723bW of the third conductive members 723U, 723V, 723W are inserted. The sub-assembly 98 that has passed the continuity test is accommodated.
Accordingly, as shown in FIG. 7B, in the vicinity of the first opening 102, the one end portions 711bU, 711bV, and 711bW are adjacent to the one end portions 712bU, 712bV, and 712bW, respectively. In this state, the welding tool 112 is inserted into the ECU chamber 37 through the second opening 102 and a welding operation is performed. Thereby, the first coupling portions 73U, 73V, and 73W are formed.

Similarly, in the vicinity of the third opening 103, the one end portions 723bU, 723bV, and 723bW are adjacent to the one end portions 724bU, 724bV, and 724bW, respectively. In this state, the welding tool 112 is inserted into the ECU chamber 37 through the third opening 103 to perform a welding operation. Thereby, the 2nd coupling | bond part 74 is formed.
As described above, according to the present embodiment, the current from the first power circuit 75 flows through the first coil 54, and the current from the second power circuit 80 flows through the second coil 55, whereby the electric motor 18. Drive. Thereby, since the electric current sent through each coil 54 and 55 can be decreased, the power loss in each coil 54 and 55 can be decreased. As a result, the power loss of the electric motor 18 as a whole can be reduced. Moreover, since electric power can be supplied to both the first and second coils 54 and 55 simultaneously, the electric motor 18 can be operated even if the current flowing through the coils 54 and 55 is small (even if the power loss is small). The maximum output of can be large enough.

  In addition, since the current flowing through the coils 54 and 55 can be reduced, the power circuits 75 and 80 can be reduced, and the coils 54 and 55 can be reduced. As a result, the electric motor unit 33 can be reduced in size. In addition, since the power boards 31 and 32 are accommodated in the first housing 23 arranged coaxially with the electric motor 18, the space around the electric motor 18 can be effectively utilized. Miniaturization can be realized.

In addition, when viewed from the axial direction X1, the power boards 31 and 32 are arranged apart from each other, so that heat from the power boards 31 and 32 can be efficiently transmitted to the first housing 23. Thereby, the heat dissipation performance of the electric motor unit 33 can be further increased.
More specifically, the first power board 31 and the second power board 32 are arranged so that the first power board 31 and the second power board 32 are arranged across the reference straight line L2 when viewed from the axial direction X1. The power board 32 can be spaced apart.

Further, when viewed from the axial direction X1, the outer portion 31a of the first power board 31 and the outer portion 32a of the second power board 32 are arranged point-symmetrically about the central axis L1. Further, when viewed from the axial direction X1, the outer portion 31a of the first power board 31 and the outer portion 32a of the second power board 32 are arranged symmetrically about the reference straight line L2.
Thereby, the two power boards 31 and 32 can be arranged so as to surround the central axis L <b> 1 of the electric motor 18. Therefore, the amount by which the two power boards 31 and 32 protrude in the radial direction R1 can be reduced, and the electric motor unit 33 can be further reduced in size. Further, when the two power boards 31 and 32 are formed by punching from a single plate-like substrate material, the number of the power boards 31 and 32 that can be punched from the material 110 having a certain size is increased. it can. Thereby, the 1st power board 31 and the 2nd power board 32 can be formed efficiently from one material.

  Furthermore, since the first bus bar 71U is formed by the first and second conductive members 711U and 712U formed separately, the degree of freedom of the shape of each conductive member 711U and 712U can be increased. As a result, the first bus bar 71U can be compactly arranged in the first housing 23 while avoiding contact with other components. Thereby, further miniaturization of the electric motor unit 33 can be realized. The same applies to the first bus bars 71V and 71W.

  Moreover, since each 2nd bus-bar 72 is formed with the 3rd and 4th electrically-conductive members 723U and 724U formed separately, the freedom degree of the shape of each electrically-conductive member 723U and 724U can be made high. As a result, the second bus bar 72U can be compactly arranged in the first housing 23 while avoiding contact with other components. Thereby, further miniaturization of the electric motor unit 33 can be realized. The same applies to the second bus bars 72V and 72W.

  Furthermore, when viewed from the axial direction X1, the first coupling portions 73U, 73V, and 73W and the second coupling portions 74U, 74V, and 74W face each other along the second direction D2. Thereby, the 1st power board 31, the 2nd power board 32, the 1st joint part 73U, V, and W and the 2nd joint part 74U, 74V, and 74W can be arranged efficiently. Thereby, since the dead space in the 1st housing 23 can be decreased, the further miniaturization of the electric motor unit 33 is realizable.

  The first coupling portions 73U, 73V, 73W and the second coupling portions 74U, 74V, 74W are arranged so as to be exposed to the second opening 102 and the third opening 103, respectively. Thereby, between the exterior of the first housing 23 and the first coupling portions 73U, 73V, 73W, and between the exterior of the first housing 23 and the second coupling portions 74U, 74V, 74W, respectively, the first housing It is not obstructed by the parts in 23.

Accordingly, the tool 112 for welding the one end portions 711 bU and 712 bU of the first bus bar 71 U can be easily inserted into the first housing 23 through the second opening 102. The same applies to the first bus bars 71V and 71W and the second bus bars 72U, 72V and 72W. Thereby, the effort of the assembly of the electric motor unit 33 can be reduced.
In the present embodiment, the welding operation of the first coupling portions 73U, 73V, and 73W and the welding operation of the second coupling portions 74U, 74V, and 74W are performed in a state where the subassembly 98 is assembled in the first housing 23. be able to. Therefore, the welding operation described above can be performed after conducting a continuity test between the power circuits 75 and 80 of the subassembly 98 and the control circuit 99.

Thereby, useless work of connecting the coils 54 and 55 to the sub-assembly 98 including the defective power circuits 75 and 80 and the control circuit 99 can be suppressed. As a result, the occurrence of defective products can be reduced.
Further, the control board 35 is disposed between the first coupling portions 73U, 73V, 73W and the second coupling portions 74U, 74V, 74W in the second direction D2. Thus, the first coupling portions 73U, 73V, 73W and the second coupling portions 74U, 74V, 74W are disposed outside the control board 35. Therefore, it is easy to perform a welding operation for forming these coupling portions.

Further, by inserting the tool 112 into the first housing 23 from the second and third openings 102 and 103 that open toward the outside in the radial direction R1, welding work in each of the coupling portions 73U to 73W and 74U to 74W is performed. Can be easily performed.
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 outer portions 31a and 32a of the power boards 31 and 32 do not have to be arranged point-symmetrically when viewed from the axial direction X1. Further, the outer portions 31a and 32a of the power boards 31 and 32 do not have to be arranged symmetrically when viewed from the axial direction X1.
Further, when viewed from the axial direction X1, the first and second power circuits 75 and 80 do not have to be point-symmetrical. For example, the first and second power circuits 75 and 80 may have a line-symmetrical arrangement around the reference straight line L2 as shown in FIG. Good.

Further, the second opening 102 and the third opening 103 of the peripheral wall 42 may be omitted.
The first conductive member 711U and the second conductive member 712U are not limited to welding, and may be fixed by other fixing means such as soldering. The same applies to other welding locations.

  DESCRIPTION OF SYMBOLS 18 ... Electric motor, 23 ... 1st housing (housing), 31 ... 1st power board, 31a ... Outer part of 1st power board, 32 ... 2nd power board, 32a ... Outer part of 2nd power board, 33 ... Electric motor unit, 35 ... control board, 42 ... peripheral wall, 54 ... first coil, 55 ... second coil, 71U, 71V, 71W ... first bus bar, 711U, 711V, 711W ... first conductive member, 712U, 712V, 712W, second conductive member, 72U, 72V, 72W, second bus bar, 723U, 723V, 723W, third conductive member, 724U, 724V, 724W, fourth conductive member, 73U, 73V, 73W, first coupling portion, 74U, 74V, 74W ... second coupling part, 75 ... first power circuit, 80 ... second power circuit, 99 ... control circuit, 101, 102, 103 ... opening D1 ... first direction, D2 ... second direction, L1 ... center axis of the electric motor, L2 ... reference line, X1 ... axial direction of the central axis line.

Claims (5)

An electric motor including a first coil and a second coil;
A first power substrate on which a first power circuit for supplying power to the first coil is formed;
A second power substrate formed with a second power circuit for supplying power to the second coil and formed using a member different from the first power substrate;
A housing that is adjacent to the first and second coils in the axial direction of the electric motor and that surrounds the central axis of the electric motor, and that houses the first and second power boards;
A plurality of conductive members and a first coupling portion that couples the conductive members to each other in the housing, and holds the first coil and the first power circuit on the first coil by a resin-made holding member; A first bus bar for electrical connection via the first motor bus bar unit,
A plurality of conductive members and a second coupling portion for coupling these conductive members to each other in the housing, and holding the second coil and the second power circuit with the resin holding member on the first coil A second bus bar for electrical connection via the second motor bus bar unit ,
When viewed from the axial direction of the central axis, the first and second coupling portions are arranged symmetrically with respect to the central axis and spaced apart from each other,
The first and second bus bars are arranged point-symmetrically with respect to the central axis as viewed from the axial direction of the central axis.
The first coil and the second coil are centered on a reference axis that intersects the central axis when viewed from the axial direction of the central axis so that the wiring thicknesses of the first and second coils are equal to each other and the wiring lengths of the first and second coils are equal to each other. Are arranged in line symmetry as
The first and second power boards are separated from each other so as to face each other across a reference axis that intersects the central axis when viewed from the axial direction of the central axis along the flat inner bottom surface of the housing. Has been placed ,
When viewed from the axial direction of the central axis, the outer portions of the first and second power boards are arranged symmetrically with respect to the central axis, and symmetrical with respect to the reference axis. electric motor unit, characterized in that is. 2. The control board according to claim 1, wherein said first and second bus bars, said first and second power boards, a control board on which a control circuit for controlling driving of said first and second power circuits is formed, and each said power An electric motor unit comprising a subassembly in which a circuit and a connection line connecting the control circuit are held by a module including a resin member. 3. The first and second coupling portions according to claim 2 , wherein when viewed from the axial direction of the central axis, the first and second coupling portions are along a second direction orthogonal to the first direction in which the first and second power substrates are opposed to each other. Opposite each other,
The electric motor unit, wherein the first and second coupling portions are arranged so as to be exposed to an opening formed in the housing . 4. The control board according to claim 3 , wherein a control circuit for controlling driving of the first and second power circuits is formed and disposed in the housing. The control board is disposed between the first coupling portion and the second coupling portion. An electric motor unit characterized by that. 5. The electric motor according to claim 3 , wherein the housing includes a peripheral wall that surrounds the first and second coupling portions, and the opening is formed by cutting out a part of the peripheral wall. Motor unit.

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