WO2019026422A1

WO2019026422A1 - Structure, stator, and motor

Info

Publication number: WO2019026422A1
Application number: PCT/JP2018/022025
Authority: WO
Inventors: 俊輔村上; 剛央新子; 崇宣小山
Original assignee: 日本電産株式会社
Priority date: 2017-08-01
Filing date: 2018-06-08
Publication date: 2019-02-07
Also published as: CN110870172A

Abstract

A structure having: a tubular support surface extending in the magnetic core direction of a coil; and a coil constituted by a conducting wire wound on the support surface. The support surface is a quadrilateral shape in which the long sides and the short sides are alternately aligned as seen in the magnetic core direction. The support surface has a pair of first support surfaces corresponding to the short sides, and a pair of second support surfaces corresponding to the long sides. The conducting wire is wound in a winding direction around the support surface from a winding start part in contact with the support surface toward a winding end part set at a distance farther from the support surface than the winding start part. At least one of the pair of first support surfaces is an inclined surface that intersects at an obtuse angle with respect to the second support surface positioned to the downstream side in the winding direction.

Description

Structure, stator, and motor

The present invention relates to a structure including a coil, a stator including the structure, and a motor including the stator.

Conventionally, the coil of the motor is formed by winding a conducting wire around the teeth to be the magnetic core through the insulator of the insulator. Inside the motor, a plurality of such coils are arranged around a central axis. Moreover, in order to arrange many coils around the central axis, the cross-sectional shape of the teeth may be a rectangular shape that is long in the axial direction and short in the circumferential direction.

The structures of teeth, an insulator, and a coil included in a conventional motor are described in, for example, Japanese Patent Application Laid-Open Nos. 2003-190951 and 2010-519471.
JP 2003-190951 A JP, 2010-519471, A

When winding the conducting wire around the teeth via the insulator, the conducting wire may expand in the circumferential direction. In particular, in the case where the cross-sectional shape of the teeth is the rectangular shape described above, swelling (lifting) of the conducting wire with respect to both end surfaces in the circumferential direction of the insulator becomes large. The bulge of the wire is more pronounced as the wire with a larger wire diameter is used. In order to arrange more coils around the central axis, it is required to suppress the wire bulge.

An object of the present invention is to provide a structure capable of suppressing the expansion of a lead with respect to a support surface in a structure including a coil.

An exemplary first invention of the present application is a structure including a coil, wherein the coil includes a cylindrical support surface extending in a direction of a magnetic core of the coil, and a conductive wire wound around the support surface. And the support surface is a quadrilateral shape in which long sides and short sides are alternately arranged as viewed in the magnetic core direction, and a pair of first support surfaces corresponding to the short sides and the long sides A corresponding pair of second support surfaces, and the conductive wire is supported from the winding start portion in contact with the support surface toward the winding end portion farther from the support surface than the winding start portion. The sheet is wound around in a winding direction, and at least one of the pair of first support surfaces is an inclined surface intersecting at an obtuse angle with respect to the second support surface located on the downstream side of the winding direction. .

According to the first exemplary invention of the present application, the conducting wire bends at an obtuse angle from the first support surface to the second support surface. Thereby, the expansion of the wire at the second support surface can be suppressed more than when the wire is bent at a right angle.

FIG. 1 is a longitudinal sectional view of a motor. FIG. 2 is a perspective view of the first resin member. FIG. 3 is a top view of a portion of the stator core and the insulator. FIG. 4 is a cross-sectional view of the stator core and the insulator as viewed from the position AA in FIG. FIG. 5 is a cross-sectional view of the teeth and the insulator as viewed from the position AA in FIG. FIG. 6 is a view showing a comparative example where there is no projection.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the present application, a direction parallel to the central axis of the motor is "axial direction", a direction perpendicular to the central axis of the motor is "radial direction", and a direction along an arc centered on the central axis of the motor is "circumferential direction" , Respectively. In the present application, the axial direction is the vertical direction, and the shape and positional relationship of each part will be described with the bus bar assembly side up with respect to the stator. However, the definition in the vertical direction is not intended to limit the direction at the time of manufacture and use of the motor according to the present invention.

The above-mentioned "parallel direction" also includes a substantially parallel direction. The “orthogonal direction” described above also includes a substantially orthogonal direction.

<1. Overall configuration of motor>

FIG. 1 is a longitudinal sectional view of a motor 1 according to an embodiment of the present invention. The motor 1 of the present embodiment is mounted, for example, on an automobile and used as a drive source for generating a drive force of the electric power steering apparatus. However, the motor of the present invention may be used for applications other than power steering. For example, the motor of the present invention may be used as a drive source of other parts of a car, such as an engine cooling fan and an oil pump. Further, the motor of the present invention may be mounted on a home appliance, an OA device, a medical device or the like to generate various driving forces.

As shown in FIG. 1, the motor 1 has a stationary unit 2 and a rotating unit 3. The stationary unit 2 is fixed to the frame of the device to be driven. The rotating unit 3 is rotatably supported with respect to the stationary unit 2.

The stationary portion 2 of the present embodiment includes a housing 21, a stator 22, a bus bar assembly 23, a lower bearing portion 24, and an upper bearing portion 25.

The housing 21 has a cylindrical portion 211, a bottom plate portion 212, and a lid portion 213. The cylindrical portion 211 extends in a substantially cylindrical shape in the axial direction on the radially outer side of the stator 22 and the bus bar assembly 23. The bottom plate portion 212 extends substantially perpendicularly to the central axis 9 below the stator 22 and a rotor 32 described later. The lid portion 213 extends substantially perpendicularly to the central axis 9 above the bus bar assembly 23. The stator 22, the bus bar assembly 23, and a rotor 32 described later are accommodated in the internal space of the housing 21.

The cylindrical portion 211, the bottom plate portion 212, and the lid portion 213 are made of, for example, a metal such as aluminum or stainless steel. In the present embodiment, the cylindrical portion 211 and the bottom plate portion 212 are constituted by one member, and the lid portion 213 is constituted by the other member. However, the cylindrical portion 211 and the lid portion 213 may be configured as one member, and the bottom plate portion 212 may be configured as another member.

The stator 22 is disposed radially outward of a rotor 32 described later. The stator 22 has a stator core 41, a plurality of insulators 42, and a plurality of coils 43. In the present embodiment, the stator core 41 is a laminated steel plate in which a plurality of electromagnetic steel plates are laminated in the axial direction. The stator core 41 has an annular core back 411 and a plurality of teeth 412 protruding radially inward from the core back 411. The core back 411 is disposed substantially coaxial with the central axis 9. Further, the outer peripheral surface of the core back 411 is fixed to the inner peripheral surface of the cylindrical portion 211 of the housing 21. The plurality of teeth 412 are arranged at substantially equal intervals in the circumferential direction. The stator core 41 may be a powder magnetic core or the like instead of the laminated steel plate.

In the present embodiment, the material of the insulator 42 is a resin which is an insulator. The stator 22 of the present embodiment has an insulator 42 for each tooth. At least a part of the surface of stator core 41 is covered with insulator 42. Specifically, of the surfaces of the stator core 41, at least the upper surface, the lower surface, and both end surfaces in the circumferential direction of each tooth 412 are covered with the insulator 42. Each insulator 42 has a first resin member 421 and a second resin member 422. The second resin member 422 is located below the first resin member 421. The first resin member 421 is attached to the stator core 41 from the upper side of the stator core 41. The second resin member 422 is attached to the stator core 41 from the lower surface side of the stator core 41.

The more detailed structure of the insulator 42 will be described later.

The coil 43 is constituted by a conducting wire 430 wound around the insulator 42. That is, in the present embodiment, the conducting wire 430 is wound around the teeth 412 to be the magnetic core via the insulator 42. The insulator 42 can prevent the electrical short between the teeth 412 and the coil 43 by interposing between the teeth 412 and the coil 43.

The bus bar assembly 23 has a bus bar 51 made of metal such as copper which is a conductor, and a bus bar holder 52 made of resin for holding the bus bar 51. The bus bar 51 is electrically connected to the conducting wire 430 that constitutes the coil 43. Further, when the motor 1 is used, a conductor extending from an external power supply (not shown) is connected to the bus bar 51. That is, coil 43 and the external power supply are electrically connected via bus bar 51. In the housing 21, a circuit board may be provided instead of the bus bar assembly 23. And the coil 43 and the external power supply may be electrically connected via the circuit board.

The lower bearing portion 24 and the upper bearing portion 25 are disposed between the housing 21 and the shaft 31 on the rotating portion 3 side. In the lower bearing portion 24 and the upper bearing portion 25 of the present embodiment, a ball bearing which relatively rotates the outer ring and the inner ring via a spherical body is used. The outer ring of the lower bearing portion 24 is fixed to the bottom plate portion 212 of the housing 21. The outer ring of the upper bearing portion 25 is fixed to the lid portion 213 of the housing 21. Further, the inner ring of each of the lower bearing portion 24 and the upper bearing portion 25 is fixed to the shaft 31. Thereby, the shaft 31 is rotatably supported with respect to the housing 21. However, instead of the ball bearings, other types of bearings such as slide bearings and fluid bearings may be used.

The rotating portion 3 of the present embodiment has a shaft 31 and a rotor 32.

The shaft 31 is a columnar member extending along the central axis 9. For the material of the shaft 31, for example, a metal such as stainless steel is used. The shaft 31 can rotate around the central axis 9 while being supported by the lower bearing portion 24 and the upper bearing portion 25 described above. The upper end portion 311 of the shaft 31 protrudes above the lid portion 213. A device to be driven is connected to the upper end portion 311 of the shaft 31 via, for example, a power transmission mechanism such as a gear. The shaft 31 may not necessarily protrude upward in the axial direction from the lid 213. That is, the bottom portion 212 may be provided with a through hole, and the lower end portion of the shaft may protrude below the bottom portion 212 through the through hole. Also, the shaft may be a hollow member.

The rotor 32 is located radially inward of the stator 22 and rotates with the shaft 31. The rotor 32 has a rotor core 61, a plurality of magnets 62, and a magnet holder 63. In the present embodiment, the rotor core 61 is a laminated steel plate in which a plurality of electromagnetic steel plates are laminated in the axial direction. Rotor core 61 has an axially extending through hole 60 at its center. The shaft 31 is press-fit into the through hole 60 of the rotor core 61. Thereby, the rotor core 61 and the shaft 31 are fixed to each other. A member such as a bush may be disposed between the inner side surface of the through hole 60 and the outer side surface of the shaft 31. That is, the shaft 31 and the rotor core 61 may be fixed directly or may be fixed indirectly. The rotor core 61 may be a dust core or the like instead of the laminated steel plate.

The plurality of magnets 62 are fixed to the outer peripheral surface of the rotor core 61 by, for example, an adhesive. The radially outer surface of each magnet 62 is a magnetic pole surface that faces the radially inner end surface of the teeth 412. The plurality of magnets 62 are arranged in the circumferential direction so that the N pole and the S pole are alternately arranged. In place of the plurality of magnets 62, one annular magnet may be used in which the N pole and the S pole are alternately magnetized in the circumferential direction.

The magnet holder 63 is a member made of resin fixed to the rotor core 61. The magnet holder 63 is obtained, for example, by insert molding using the rotor core 61 as an insert part. The lower surfaces and both end surfaces in the circumferential direction of the plurality of magnets 62 contact the magnet holder 63. Thereby, each magnet 62 is positioned in the circumferential direction and the axial direction. Further, the rigidity of the entire rotor 32 is enhanced by the magnet holder 63. The plurality of magnets 62 may be fixed to the rotor core 61 by a mold using a resin, or may be fixed indirectly using other members.

When a drive current is supplied to the coil 43 from the external power supply via the bus bar 51, magnetic flux is generated in the plurality of teeth 412 of the stator core 41. Then, the action of the magnetic flux between the teeth 412 and the magnet 62 generates torque in the circumferential direction. As a result, the rotating unit 3 rotates around the central axis 9 with respect to the stationary unit 2.

<2. About the structure of insulator and coil>

Then, the structure which winds the conducting wire 430 which comprises the coil 43 around the insulator 42 is demonstrated in more detail. FIG. 2 is a perspective view of the first resin member 421. As shown in FIG. FIG. 3 is a top view of a portion of stator core 41 and insulator 42. As shown in FIG. FIG. 4 is a cross-sectional view of the stator core 41 and the insulator 42 viewed from the AA position of FIG. In FIG. 4, hatching representing a cross section of the insulator 42 is omitted. Hereinafter, the direction in which the teeth 412 as the magnetic core of the coil 43 extend is referred to as the “magnetic core direction”.

As shown in FIGS. 2 to 4, the insulator 42 has a cylindrical support surface 70 extending in the magnetic core direction. The support surface 70 has a pair of first support surfaces 71 and a pair of second support surfaces 72. The support surface 70 has a rectangular shape in which short sides and long sides are alternately arranged around the teeth 412 when viewed in the axial direction. The first support surface 71 is a surface corresponding to the short side. The second support surface 72 is a surface corresponding to the long side. Hereinafter, the direction along the short side is referred to as "short side direction", and the direction along the long side is referred to as "long side direction".

In the present embodiment, the upper and lower surfaces of the insulator 42 become the first support surface 71. Both end surfaces in the circumferential direction of the insulator 42 become a second support surface 72. The first resin member 421 includes the upper surface of the insulator 42 which is one of the pair of first support surfaces 71. The second resin member 422 includes the lower surface of the insulator 42 which is the other of the pair of first support surfaces 71.

The conducting wire 430 constituting the coil 43 is wound around the support surface 70 of the insulator 42. The support surface 70 and the coil 43 constitute an example of the “structure” in the present invention. The winding start of the conducting wire 430 with respect to one insulator 42 contacts the support surface 70 of the insulator 42. The winding end of the conductor 430 with respect to one insulator 42 is farther from the support surface 70 than the winding start. The conductor 430 is wound around the support surface 70 multiple times from the beginning of the winding to the end of the winding.

By shortening the length in the short side direction of the first support surface 71, the large number of coils 43 can be densely arranged in the circumferential direction. Also, by increasing the length in the long side direction of the second support surface 72, the magnetic path inside the coils 43 can be made wider. The length of the second support surface 72 in the long side direction is preferably, for example, five or more times the length of the first support surface 71 in the short side direction.

The pair of first support surfaces 71 is an inclined surface which is inclined with respect to the axial direction. The angle θ between the first support surface 71 and the second support surface 72 located on the downstream side in the winding direction with respect to the first support surface 71 is an obtuse angle larger than 90 °. That is, the first support surface 71 intersects at an obtuse angle with the second support surface 72 located on the downstream side in the winding direction.

FIG. 5 is a cross-sectional view of the teeth 412 and the insulator 42 viewed from the AA position of FIG. FIG. 6 is a view showing a comparative example in which the first support surface 71 is not an inclined surface but perpendicular to the axial direction. In FIGS. 5 and 6, the winding direction of the conducting wire from the winding start to the winding end is indicated by a double dotted dashed arrow. As shown in FIG. 6, when the first support surface 71X is perpendicular to the axial direction, the conducting wire 430X is bent substantially at right angles from the first support surface 71X to the second support surface 72X. In this case, the bulging (lifting) of the conducting wire 430X on the second support surface 72X becomes large. As a result, the circumferential width of the coil is increased.

On the other hand, in the present embodiment, as shown in FIG. 5, the conducting wire 430 bends at an obtuse angle from the first support surface 71 to the second support surface 72. For this reason, the swelling (lifting) of the conducting wire 430 on the second support surface 72 is suppressed more than in the case of FIG. Therefore, the circumferential width of the coil 43 can be reduced compared to the case of FIG. As a result, the multiple coils 43 can be densely arranged in the circumferential direction while preventing the conducting wires 430 of the adjacent coils 43 from coming in contact with each other.

According to the structure of the present embodiment, the number of windings of the conducting wire 430 with respect to one tooth 412 can be increased within the range of the limited circumferential direction. In addition, the diameter of the wire 430 to be wound can be increased to allow a larger current to flow. Thereby, the output of the motor 1 can be improved.

However, if the angle θ between the first support surface 71 and the second support surface 72 is too large, the axial length of the stator 22 becomes long. Therefore, it is preferable that the angle θ be larger than 90 ° and be the smallest angle at which the expansion of the conducting wire 430 on the second support surface 72 can be suppressed within the allowable range. For example, the angle θ is preferably smaller than 135 °. It is more preferable that the angle θ be smaller than 120 °.

As shown in FIGS. 4 and 5, the support surface 70 of the present embodiment is viewed in the axial direction between the first support surface 71 and the second support surface 72 located on the downstream side in the winding direction. A curved surface 76 having a substantially arc shape is provided. The curved surface 76 smoothly connects the first support surface 71 and the second support surface 72 located on the downstream side in the winding direction. The conductor 430 from the first support surface 71 to the second support surface 72 gently bends along the curved surface 76. Thereby, the swelling of the conducting wire 430 in the second support surface 72 is further suppressed.

In the present embodiment, both of the pair of first support surfaces 71 are the above-described inclined surfaces. For this reason, the swelling of the conducting wire 430 with respect to the one second support surface 72 and the swelling of the conducting wire 430 with respect to the other second support surface 72 are both suppressed. As a result, the circumferential width of the coil 43 can be further reduced.

In the present embodiment, the pair of first support surfaces 71 are parallel to each other, and the pair of second support surfaces 72 are parallel to each other. That is, the cylindrical support surface 70 is a parallelogram when viewed in the axial direction. In this way, the parts can be made common by making the shape of the first resin member 421 the same as the shape of the second resin member 422. Thereby, the manufacturing cost of the motor 1 can be reduced. However, the inclination angles of the pair of first support surfaces 71 may be different.

Further, the motor 1 of the present embodiment is a so-called inner rotor type motor in which the rotor 32 is positioned radially inward of the stator 22. In the case of the inner rotor type, the coils 43 adjacent in the circumferential direction easily approach each other. However, according to the structure of the present embodiment, the wire 430 can be prevented from expanding in the circumferential direction. Therefore, it can suppress that the conducting wire 430 comrades of the adjacent coil 43 contact.

<3. Modified example>

As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to the above-mentioned embodiment.

In the above embodiment, the insulator 42 is a two-part member of the first resin member 421 including one of the pair of first support surfaces 71 and the second resin member 422 including the other of the pair of first support surfaces 71. It was configured. However, the insulator 42 may have a single cylindrical resin member including both of the pair of first support surfaces 71.

In the above embodiment, the conducting wire 430 is wound around the teeth 412 of the stator core 41 via the insulator 42. For this reason, the cylindrical support surface 70 which supports the conducting wire 430 is provided on the insulator 42. However, the conducting wire 430 may be directly wound around the teeth 412 of the stator core 41 whose insulator 42 is omitted and the surface is coated with an insulator. In that case, the teeth 412 themselves may have the same support surface as the support surface 70 of the insulator 42 described above.

In the above embodiment, both of the pair of first support surfaces 71 are inclined surfaces. However, only one of the pair of first support surfaces 71 may be an inclined surface. Even in this case, the swelling (lifting) of the conducting wire 430 in at least one of the pair of second support surfaces 72 is suppressed. Therefore, the circumferential width of the coil can be reduced.

In the above embodiment, a so-called inner rotor type motor in which the rotor 32 is positioned radially inward of the stator 22 has been described. However, the structure, the stator and the motor of the present invention may be applied to a so-called outer rotor type motor in which the rotor is located radially outward of the stator.

In the above embodiment and modification, the structure included in the motor has been described. However, the structure of the present invention may be included in equipment other than a motor such as a generator.

The plurality of magnets do not necessarily have to be located on the outer peripheral surface of the rotor core. At least a portion of the magnet may be embedded in the rotor core.

Furthermore, the motor may have a control board that controls energization of the stator. In this case, the control board is electrically connected to the bus bar. Also, the motor may not have the bus bar assembly. In this case, the conducting wire is electrically connected to a connector or the like connected to an external power supply. Also, even when the motor has a control board, the motor may not have the bus bar assembly. In this case, the conducting wire is electrically connected to the control substrate without passing through the bus bar assembly.

The shape of the detail of each member may be different from the shape shown in each drawing of the present application. The elements appearing in the above-described embodiment and modifications may be combined as appropriate as long as no contradiction occurs.

The present invention is applicable to a structure including a coil, a stator including the structure, and a motor including the stator.

Reference Signs List 1 motor, 2 stationary portion, 3 rotating portion, 9 central shaft, 21 housing, 22 stator, 23 bus bar assembly, 24 lower bearing portion, 25 upper bearing portion, 31 shaft, 32 rotor, 41 stator core, 42 insulator, 43 coil, 70 support surface, 71 first support surface, 72 second support surface, 76 curved surface, 411 core back, 412 teeth, 421 first resin member, 422 second resin member, 430 conductor

Claims

A structure including a coil,

A cylindrical support surface extending in a magnetic core direction of the coil;

The coil comprising a conductive wire wound around the support surface;

Have

The support surface is a quadrangular shape in which long sides and short sides are alternately arranged as viewed in the magnetic core direction, and a pair of first support surfaces corresponding to the short sides and a pair corresponding to the long sides. And a second support surface,

The conductive wire is wound around the support surface in a winding direction from a start of winding contacting the support surface toward an end of wrap farther from the support surface than the start of winding.

At least one of the pair of first support surfaces is an inclined surface intersecting at an obtuse angle with respect to the second support surface located on the downstream side in the winding direction.
The structure according to claim 1, wherein

The obtuse angle is a structure smaller than 135 °.
The structure according to claim 1, wherein

The structure wherein the support surface further has a curved surface smoothly connecting the first support surface and the second support surface.
A structure according to any one of claims 1 to 3, which is:

The structure in which both of the pair of first support surfaces are the inclined surfaces.
The structure according to claim 4, wherein

The pair of first support surfaces are parallel to each other,

The structure in which the pair of second support surfaces are parallel to each other.
The structure according to any one of claims 1 to 5, wherein

The structure whose length of the said long side direction of a said 2nd support surface is 5 times or more of the length of the said short side direction of a said 1st support surface.
A stator including the structure according to any one of claims 1 to 6,

Stator core,

A resin insulator covering at least a part of the stator core;

The coil,

Have

A stator having the support surface;
The stator according to claim 7, wherein

The insulator is

A first resin member including one of the pair of first support surfaces;

A second resin member including the other of the pair of first support surfaces;

With a stator.
The stator according to claim 7, wherein

The insulator is

A stator having a cylindrical resin member including both of the pair of first support surfaces.
A stator including the structure according to any one of claims 1 to 6,

Stator core whose surface is coated with insulation,

And the coil;

A stator wherein the stator core has the support surface.
A stator according to any one of claims 7 to 10;

A rotor rotating with respect to the stator;

With a motor.
The motor according to claim 11, wherein

The motor is located radially inward of the stator.
A motor according to claim 11 or 12, wherein

A motor serving as a drive source of an electric power steering device.