CN110870172A

CN110870172A - Structure, stator, and motor

Info

Publication number: CN110870172A
Application number: CN201880045948.5A
Authority: CN
Inventors: 村上俊辅; 新子刚央; 小山崇宣
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2017-08-01
Filing date: 2018-06-08
Publication date: 2020-03-06
Also published as: WO2019026422A1

Abstract

The structure has: a cylindrical support surface extending in a magnetic core direction of the coil; and a coil formed of a wire wound around the support surface. The support surface has a rectangular shape in which long sides and short sides are alternately arranged when viewed in the 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 conductive wire is wound around the support surface in the winding direction from a winding start portion that is in contact with the support surface toward a winding end portion that is farther from the support surface than the winding start portion. At least one of the pair of first support surfaces is an inclined surface that intersects the second support surface located on the downstream side in the winding direction at an obtuse angle.

Description

Structure, stator, and motor

Technical Field

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

Background

Conventionally, a coil of a motor is formed by winding a wire around a tooth as a core with an insulator interposed therebetween. A plurality of such coils are arranged around a central axis in the motor. 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.

For example, japanese patent application laid-open nos. 2003-190951 and 2010-519471 describe structures of teeth, insulators, and coils included in conventional motors.

Patent document 1: japanese patent laid-open publication No. 2003-190951

Patent document 2: japanese patent application laid-open No. 2010-519471

Disclosure of Invention

Problems to be solved by the invention

When the wire is wound around the teeth with the insulator interposed therebetween, the wire may bulge in the circumferential direction. In particular, when the cross-sectional shape of the teeth is the above-described rectangular shape, the protrusions (bulges) of the lead with respect to both end surfaces in the circumferential direction of the insulator become large. The more a wire having a large wire diameter is used, the more conspicuous the rise of the wire is generated. In order to arrange more coils around the central axis, it is required to suppress the bulging of the wire.

The present invention aims to provide a structure capable of suppressing a wire from bulging from a support surface in a structure including a coil.

Means for solving the problems

A first exemplary aspect of the present invention is a structure including a coil, the structure including: a cylindrical support surface extending in a core direction of the coil; and the coil, it is formed by the wire that is wound on the said supporting surface, when observing along the said magnetic core direction, the said supporting surface is the quadrilateral shape that the long side and short side are arranged alternately, have a pair of first supporting surfaces equivalent to said short side and a pair of second supporting surfaces equivalent to said long side, the said wire is wound along the winding direction around the said supporting surface from the beginning of winding to the winding ending part, this winding beginning part contacts with said supporting surface, this winding ending part is far away from the said supporting surface than the said winding beginning part, at least one in a pair of first supporting surfaces is the inclined plane that intersects with the said second supporting surface that is located downstream side of the said winding direction at obtuse angle.

Effects of the invention

According to the exemplified first invention of the present application, the wire is bent at an obtuse angle from the first support surface toward the second support surface. This can suppress the wire from bulging at the second support surface, as compared with the case where the wire is bent at a right angle.

Drawings

Fig. 1 is a longitudinal sectional view of the motor.

Fig. 2 is a perspective view of the first resin member.

Fig. 3 is a plan view of a portion of the stator core and the insulator.

Fig. 4 is a sectional view of the stator core and the insulator as viewed from a-a position of fig. 3.

Fig. 5 is a cross-sectional view of the tooth and insulator as viewed from a-a of fig. 3.

Fig. 6 is a diagram showing a comparative example in the case where there is no protrusion.

Detailed Description

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 referred to as an "axial direction", a direction perpendicular to the central axis of the motor is referred to as a "radial direction", and a direction along an arc centered on the central axis of the motor is referred to as a "circumferential direction". In the present application, the shapes and positional relationships of the respective portions will be described with the axial direction as the vertical direction and the bus bar assembly side as the upper side with respect to the stator. However, the orientation of the motor of the present invention during manufacture and during use is not intended to be limited by the definition of the vertical direction.

The "parallel direction" also includes a substantially parallel direction. The "vertical direction" also includes a substantially vertical direction.

< 1. integral structure 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 on, for example, an automobile, and is used as a drive source for generating a drive force of an 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 for other parts of an automobile, such as an engine cooling fan and an oil pump. The motor of the present invention may be mounted in home electric appliances, Office Automation (OA) equipment, medical equipment, and the like, and may generate various driving forces.

As shown in fig. 1, the motor 1 includes a stationary portion 2 and a rotating portion 3. The stationary unit 2 is fixed to a housing of a device to be driven. The rotating portion 3 is supported to be rotatable with respect to the stationary portion 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 includes 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 outer side in the radial direction of the stator 22 and the bus bar assembly 23. The bottom plate portion 212 extends substantially perpendicularly to the center axis 9 at a position below the stator 22 and a rotor 32 described later. The cover 213 is extended substantially perpendicularly to the center axis 9 at a position above the bus bar assembly 23. The stator 22, the bus bar assembly 23, and a rotor 32 described later are housed in an internal space of the housing 21.

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

The stator 22 is disposed radially outward of the 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 sheet in which a plurality of electromagnetic steel sheets 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 arranged substantially coaxially with the central axis 9. 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 dust core or the like instead of the laminated steel sheet.

In the present embodiment, the material of the insulating member 42 is a resin as an insulator. The stator 22 of the present embodiment has an insulator 42 at each tooth. At least a part of the surface of the stator core 41 is covered with an insulator 42. Specifically, at least the upper surface, the lower surface, and both circumferential end surfaces of each tooth 412 of the surface of the stator core 41 are covered with the insulator 42. Each insulating member 42 has a first resin part 421 and a second resin part 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.

More detailed configuration of the insulating member 42 will be described later.

The coil 43 is formed of a conductive wire 430 wound around the insulator 42. That is, in the present embodiment, the lead wire 430 is wound around the teeth 412 as the magnetic core via the insulator 42. The insulator 42 is sandwiched between the teeth 412 and the coil 43, thereby preventing the teeth 412 and the coil 43 from being electrically short-circuited.

The bus bar assembly 23 includes a bus bar 51 made of metal such as copper as a conductor, and a resin-made bus bar holder 52 for holding the bus bar 51. The bus bar 51 is electrically connected to the lead wire 430 constituting the coil 43. When the motor 1 is used, a lead wire extending from an external power supply (not shown) is connected to the bus bar 51. That is, the coil 43 and the external power supply are electrically connected via the bus bar 51. In addition, a circuit board may be provided in the housing 21 instead of the bus bar assembly 23. Further, the coil 43 and an external power source may be electrically connected via a 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 present embodiment, the lower bearing portion 24 and the upper bearing portion 25 use ball bearings in which an outer ring and an inner ring are relatively rotated via balls. The outer ring of the lower bearing portion 24 is fixed to a bottom plate portion 212 of the housing 21. The outer race of the upper bearing portion 25 is fixed to the lid portion 213 of the housing 21. Further, inner rings of the lower bearing portion 24 and the upper bearing portion 25 are fixed to the shaft 31. Thereby, the shaft 31 is supported rotatably with respect to the housing 21. However, instead of the ball bearing, another type of bearing such as a slide bearing or a fluid bearing may be used.

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

The shaft 31 is a columnar member extending along the center axis 9. The shaft 31 is made of a metal such as stainless steel. The shaft 31 is supported by the lower bearing portion 24 and the upper bearing portion 25 and is rotatable about the central axis 9. The upper end 311 of the shaft 31 protrudes upward from the lid 213. The upper end 311 of the shaft 31 is coupled to a device to be driven via a power transmission mechanism such as a gear. The shaft 31 does 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 through which the lower end portion of the shaft passes to protrude downward from the bottom portion 212. Further, the shaft may be a hollow member.

The rotor 32 is located radially inside the stator 22 and rotates together with the shaft 31. The rotor 32 includes 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 sheet in which a plurality of electromagnetic steel sheets are laminated in the axial direction. The rotor core 61 has a through hole 60 extending in the axial direction at the center thereof. The shaft 31 is press-fitted into the through hole 60 of the rotor core 61. Thereby, the rotor core 61 and the shaft 31 are fixed to each other. Further, a member such as a bush may be disposed between the inner surface constituting the through hole 60 and the outer surface of the shaft 31. That is, the shaft 31 and the rotor core 61 may be directly fixed or indirectly fixed. The rotor core 61 may be a dust core or the like instead of the laminated steel sheet.

The plurality of magnets 62 are fixed to the outer peripheral surface of the rotor core 61 with an adhesive, for example. The radially outer surface of each magnet 62 serves as a magnetic pole surface facing the radially inner end surface of the tooth 412. The plurality of magnets 62 are arranged in the circumferential direction such that N poles and S poles are alternately arranged. Instead of the plurality of magnets 62, one annular magnet may be used in which N poles and S poles are alternately magnetized in the circumferential direction.

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

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

< 2. construction of insulator and coil

Next, a structure in which the lead wire 430 constituting the coil 43 is wound around the insulator 42 will be described in more detail. Fig. 2 is a perspective view of the first resin part 421. Fig. 3 is a plan view of a part of the stator core 41 and the insulator 42. Fig. 4 is a sectional view of the stator core 41 and the insulator 42 as viewed from a-a position in fig. 3. In fig. 4, hatching showing a cross section of the insulating member 42 is omitted. Hereinafter, the direction in which the teeth 412 serving as the core of the coil 43 extend is referred to as "core direction".

As shown in fig. 2 to 4, the insulating member 42 has a cylindrical support surface 70 extending in the core direction. The bearing surface 70 has a pair of first bearing surfaces 71 and a pair of second bearing surfaces 72. When viewed in the axial direction, the support surface 70 has a quadrilateral shape in which short sides and long sides are alternately arranged around the teeth 412. 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, a direction along the short side is referred to as a "short side direction", and a direction along the long side is referred to as a "long side direction".

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

The lead 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" of the present invention. The lead wire 430 is in contact with the support surface 70 of one of the insulators 42 with respect to the winding start portion of the insulator 42. The winding end portion of the conductive wire 430 with respect to one of the insulators 42 is farther from the support surface 70 than the winding start portion. The conductive wire 430 is wound around the support surface 70 a plurality of times from the winding start portion toward the winding end portion.

By shortening the length of the first support surface 71 in the short direction, the plurality of coils 43 can be arranged closely in the circumferential direction. Further, by increasing the length of the second support surface 72 in the longitudinal direction, the magnetic path inside each coil 43 can be enlarged. The length of the second support surface 72 in the longitudinal direction is preferably 5 times or more the length of the first support surface 71 in the lateral direction, for example.

The pair of first support surfaces 71 are inclined surfaces inclined with respect to the axial direction. The angle θ formed by 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 the second support surface 72 located on the downstream side in the winding direction at an obtuse angle.

Fig. 5 is a cross-sectional view of the tooth 412 and insulator 42 from the position a-a of fig. 3. Fig. 6 is a diagram showing a comparative example in which the first support surface 71 is not an inclined surface but is perpendicular to the axial direction. In fig. 5 and 6, the winding direction of the wire from the winding start portion to the winding end portion is indicated by an arrow of a two-dot chain line. As shown in fig. 6, when the first support surface 71X is perpendicular to the axial direction, the lead wire 430X is bent at substantially right angles from the first support surface 71X toward the second support surface 72X. In this case, the bulge (bulge) of the wire 430X at the second support surface 72X becomes large. This increases the circumferential width of the coil.

In contrast, in the present embodiment, as shown in fig. 5, the lead wire 430 is bent at an obtuse angle from the first support surface 71 toward the second support surface 72. Therefore, compared with the case of fig. 6, bulging (bulging) of the wire 430 at the second bearing surface 72 is suppressed. Therefore, the width of the coil 43 in the circumferential direction can be reduced as compared with the case of fig. 6. As a result, the plurality of coils 43 can be closely arranged in the circumferential direction while preventing the conductive wires 430 of the adjacent coils 43 from contacting each other.

According to the configuration of the present embodiment, the number of windings of the wire 430 with respect to one tooth 412 can be increased within a limited circumferential range. In addition, the diameter of the wound wire 430 can also be increased, thereby allowing a greater current to flow. This can increase the output of the motor 1.

However, if the angle θ between the first support surface 71 and the second support surface 72 is too large, the length of the stator 22 in the axial direction becomes long. Therefore, the angle θ is preferably the smallest angle that is larger than 90 ° and suppresses the bulging of the wire 430 at the second supporting surface 72 within the allowable range. For example, the angle θ is preferably less than 135 °. In addition, the angle θ is more preferably less than 120 °.

As shown in fig. 4 and 5, the support surface 70 of the present embodiment has a curved surface 76 having a substantially arc shape when viewed from the axial direction between the first support surface 71 and the second support surface 72 located on the downstream side in the winding direction. The curved surface 76 gently connects the first support surface 71 and the second support surface 72 on the downstream side in the winding direction thereof. The lead 430 from the first support surface 71 toward the second support surface 72 is gently curved along the curved surface 76. Thereby, the bulging of the wire 430 at the second bearing surface 72 is further suppressed.

In the present embodiment, both of the pair of first support surfaces 71 are inclined surfaces as described above. Therefore, the bulging of the wire 430 with respect to one second supporting surface 72 and the bulging of the wire 430 with respect to the other second supporting surface 72 are both suppressed. As a result, the width of the coil 43 in the circumferential direction 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 as viewed in the axial direction. In this way, the shape of the first resin member 421 can be made the same as the shape of the second resin member 422, and the members can be made common. This can reduce the manufacturing cost of the motor 1. However, the inclination angles of the pair of first supporting surfaces 71 may be different angles.

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 are easily accessible to each other. However, according to the configuration of the present embodiment, the wire 430 can be prevented from bulging in the circumferential direction. Therefore, the wires 430 of the adjacent coils 43 can be suppressed from contacting each other.

< 3. modification example >

While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

In the above embodiment, the insulating member 42 is constituted by the following two components: a first resin member 421 including one of the pair of first supporting surfaces 71; and a second resin member 422 including the other of the pair of first supporting surfaces 71. However, the insulator 42 may have a single cylindrical resin member including both the pair of first supporting surfaces 71.

In the above embodiment, the lead wire 430 is wound around the teeth 412 of the stator core 41 via the insulator 42. Therefore, the cylindrical support surface 70 for supporting the lead wire 430 is provided on the insulator 42. However, the insulator 42 may be omitted, and the lead wire 430 may be wound directly around the teeth 412 of the stator core 41 whose surface is insulation-coated. In this case, the teeth 412 themselves may have the same shape of the support surface 70 of the insulator 42 as 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 supporting surfaces 71 may be an inclined surface. Even in this case, the bulging (bulging) of the wire 430 at least one of the pair of second bearing surfaces 72 is suppressed. Therefore, the width of the coil in the circumferential direction 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 according to the present invention may be applied to a so-called outer rotor type motor in which the rotor is positioned radially outward of the stator.

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

The plurality of magnets are not necessarily located on the outer peripheral surface of the rotor core. At least a part of the magnet may be embedded in the rotor core.

The motor may have a control board for controlling the energization of the stator. In this case, the control substrate is electrically connected to the bus bar. In addition, the motor may not have a bus bar assembly. In this case, the lead is electrically connected to a connector or the like connected to an external power supply. In addition, when the motor has a control board, the motor may not have a bus bar assembly. In this case, the lead wire is electrically connected to the control substrate without passing through the bus bar assembly.

The detailed shapes of the respective members may be different from those shown in the drawings of the present application. The respective elements appearing in the above-described embodiments or modifications may be appropriately combined within a range not to contradict each other.

Industrial applicability

The present invention can be used for a structure including a coil, a stator including the structure, and a motor including the stator.

Description of the reference symbols

1: a motor; 2: a stationary portion; 3: a rotating part; 9: a central axis; 21: a housing; 22: a stator; 23: a bus bar assembly; 24: a lower bearing portion; 25: an upper bearing portion; 31: a shaft; 32: a rotor; 41: a stator core; 42: an insulating member; 43: a coil; 70: a bearing surface; 71: a first bearing surface; 72: a second bearing surface; 76: a curved surface; 411: the back of the iron core; 412: teeth; 421: a first resin member; 422: a second resin member; 430: and (4) conducting wires.

Claims

1. A structure comprising a coil, wherein,

the structure has:

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

the coil is composed of a wire wound around the support surface,

the support surface has a quadrilateral shape in which long sides and short sides are alternately arranged when viewed in the core direction, and 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 conductive wire is wound around the support surface in a winding direction from a winding start portion that is in contact with the support surface toward a winding end portion that is farther from the support surface than the winding start portion,

at least one of the pair of first support surfaces is an inclined surface that intersects the second support surface on the downstream side in the winding direction at an obtuse angle.

2. The construct of claim 1 wherein,

the obtuse angle is less than 135 °.

3. The construct of claim 1 wherein,

the bearing surface further has a curved surface gently connecting the first bearing surface and the second bearing surface.

4. The construct of any of claims 1 to 3, wherein,

both of the pair of first support surfaces are the inclined surfaces.

5. The construct of claim 4 wherein,

the pair of first bearing surfaces are parallel to each other,

the pair of second bearing surfaces are parallel to each other.

6. The construct of any of claims 1 to 5, wherein,

the length of the second support surface in the long side direction is 5 times or more the length of the first support surface in the short side direction.

7. A stator comprising the structure of any one of claims 1 to 6,

the stator has:

a stator core;

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

the coil is provided with a plurality of coils,

the insulator has the bearing surface.

8. The stator according to claim 7,

the insulating member has:

a first resin member including one of the pair of first supporting surfaces; and

and a second resin member including the other of the pair of first supporting surfaces.

9. The stator according to claim 7,

the insulating member has a cylindrical resin member including both the pair of first supporting surfaces.

10. A stator comprising the structure of any one of claims 1 to 6,

the stator has:

a stator core, the surface of which is coated with insulation; and

the coil is provided with a plurality of coils,

the stator core has the bearing surface.

11. A motor, comprising:

the stator of any one of claims 7 to 10; and

a rotor that rotates relative to the stator.

12. The motor of claim 11,

the rotor is located radially inward of the stator.

13. The motor according to claim 11 or 12,

the motor is a driving source of the electric power steering apparatus.