WO2019008930A1

WO2019008930A1 - Stator and motor

Info

Publication number: WO2019008930A1
Application number: PCT/JP2018/019864
Authority: WO
Inventors: 将之石川
Original assignee: 日本電産テクノモータ株式会社
Priority date: 2017-07-04
Filing date: 2018-05-23
Publication date: 2019-01-10
Also published as: JPWO2019008930A1; CN110771007A

Abstract

A stator of a motor is provided with: a magnetic body stator core including an annular core back surrounding a central axis extending vertically, and a plurality of teeth extending in a radial direction from the core back; a resin insulator covering at least part of the teeth; and a coil comprising a conducting wire wound around the teeth with the insulator interposed therebetween. The stator core is divided into a plurality of regions in the axial direction by interposing a non-magnetic layer which is non-magnetic and electrically insulating.

Description

Stator and motor

The present invention relates to a stator and a motor.

Japanese Patent Application Laid-Open No. 2002-101583 discloses an electric motor for detecting the position of a rotor core. In the electric motor described in the publication, a position detection element is disposed at a position facing in the axial direction of the rotor, and the position detection element passes the magnetic flux from the magnet of the rotor to detect the position. Then, in order to increase the amount of magnetic flux to the position detection element, the length of the magnet in the axial direction of the rotation axis is increased.
Japanese Patent Application Publication No. 2002-101583

In the motor having the structure described in JP-A-2002-101583, if a large amount of magnetic flux from the magnet can be taken into the stator core, the stator core can be effectively used. As a result, the ratio of the output torque to the input power of the motor can be increased, and the efficiency of the motor can be improved. For this reason, it is desirable to increase the magnetic flux drawn into the stator core.

An object of the present invention is to provide a stator core and a motor which can take in more magnetic flux from the magnet to the stator core without increasing the thickness of the laminated thickness of the stator core.

An exemplary invention of the present application is a stator of a motor, which is a magnetic stator core having an annular core back surrounding a vertically extending central axis and a plurality of teeth radially extending from the core back. A resin insulator covering at least a part of the teeth, and a coil formed of a conducting wire wound on the teeth via the insulator, the stator core being interposed by an insulator which is nonmagnetic and electrically insulating By doing this, it is divided into a plurality of regions in the axial direction.

According to an exemplary invention of the present application, it is possible to capture more magnetic flux from the magnet as compared to a structure in which the stator core is not divided by the nonmagnetic material under the condition that the stack thickness length of the stator core is the same. Thus, the stator core can be effectively used as a magnetic path. As a result, it is possible to increase the ratio of the output power to the input power of the motor, and to improve the efficiency of the motor, by increasing the thickness thickness of the stator core, that is, without increasing the number of stator cores in the axial direction. it can.

FIG. 1 is a longitudinal sectional view of a motor. FIG. 2 is a perspective view of a stator core of the stator. FIG. 3 is a diagram for explaining the magnetic flux passing through the stator core. FIG. 4 is a diagram showing the magnetic flux distribution of the stator core. FIG. 5 is a figure for demonstrating the magnetic flux which passes along the stator core which does not provide a nonmagnetic layer. FIG. 6 is a diagram showing the magnetic flux distribution of the stator core. FIG. 7 is a diagram showing a waveform of an induced voltage generated by the magnetic flux flowing into the stator core. FIG. 8 is a figure for demonstrating the magnetic flux which passes along the stator core which divided the magnetic area | region into three by two nonmagnetic layers. FIG. 9 is a diagram showing the waveform of the induced voltage of the stator core according to the difference in the number of nonmagnetic layers. FIG. 10 is a diagram showing a separable stator core.

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. Further, in the present application, the shape and the positional relationship of each part will be described with the axial direction as the vertical direction. 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.

<1. Overall configuration of motor>
FIG. 1 is a longitudinal sectional view of the motor 1. The motor 1 is used for home appliances such as an air conditioner. However, the motor 1 may be used for applications other than home appliances. For example, the motor 1 may be mounted on transportation equipment such as a car or a railway, OA equipment, medical equipment, tools, large-scale equipment for industrial use, etc. to generate various driving forces.

The motor 1 includes a stationary unit 2 and a rotating unit 3. The stationary unit 2 is fixed to the frame of the home appliance. The rotating unit 3 is rotatably supported with respect to the stationary unit 2.

The stationary portion 2 includes a stator 21, a circuit board 22, a resin casing 23, a lower bearing portion 24, and an upper bearing portion 25.

The stator 21 is an armature that generates a magnetic flux according to the drive current. The stator 21 has a stator core 211, an insulator 212, and a plurality of coils 213.

FIG. 2 is a perspective view of a stator core 211 that the stator 21 has. The stator core 211 shown in FIG. 2 shows a state of being cut at a cross section including the central axis 9. In FIG. 2, the insulator 212 and the coil 213 are not shown.

The stator core 211 is composed of a plurality of divided cores 40. The plurality of divided cores 40 are arranged in the circumferential direction. Each divided core 40 has a core back 41 and teeth 42. The plurality of core backs 41 form an annular shape centered on the central axis 9 as a whole by contacting each other. The teeth 42 extend radially inward from the core back 41.

The split core 40 is configured by laminating a magnetic layer 40A, a nonmagnetic layer 40B, and a magnetic layer 40C in the axial direction. The

magnetic layers

40A and 40C are formed, for example, by laminating electromagnetic steel plates. The nonmagnetic layer 40B is, for example, an insulator made of a nonmagnetic and electrically insulating resin material. The magnetic layer 40A is stacked on the axial direction upper side of the nonmagnetic layer 40B, and the magnetic layer 40C is stacked on the axial direction lower side of the nonmagnetic layer 40B. That is, the magnetic region of the split core 40 is divided into a plurality of regions in the axial direction by interposing the nonmagnetic layer 40B. The stator core 211 may also be an annular core of one connection.

In the present embodiment, the nonmagnetic layer 40B divides the magnetic region of the divided core 40 equally. Therefore, the axial length of the two

magnetic layers

40A and 40C is the same. The nonmagnetic layer 40 </ b> B is disposed at the axial center of the teeth 42.

The insulator 212 is attached to the stator core 211. As a material of the insulator 212, a resin which is an insulator is used. The insulator 212 has teeth insulating portions 51 that cover both axial end surfaces of the teeth 42 and both circumferential surfaces. The coil 213 is made of a conducting wire wound around the teeth insulating portion 51. That is, the conducting wire that constitutes the coil 213 is wound around the teeth 42 through the teeth insulating portion 51 of the insulator 212.

The insulator 212 has an upper side wall 52. The upper side wall portion 52 extends from both radial inner and outer ends of the tooth insulating portion 51 toward both the axial upper side and the circumferential direction. The insulator 212 also has a lower side wall 53. The lower side wall portion 53 extends from both radial inner and outer ends of the tooth insulating portion 51 to both the axial lower side and the circumferential direction. The upper side wall portion 52 and the lower side wall portion 53 suppress the winding collapse of the coil 213, and prevent the wire constituting the coil 213 from protruding radially inward and outward.

The insulator 212 may be the same member as the nonmagnetic layer 40B, or may be a separate member from the nonmagnetic layer 40B.

The circuit board 22 is located on the axial direction upper side of the stator 21 and disposed substantially perpendicular to the central axis 9. The circuit board 22 is fixed to the upper end portion of the insulator 212 by welding, for example. An electric circuit for supplying a driving current to the coil 213 is mounted on the circuit board 22. The ends of the conductive wires constituting the coil 213 are electrically connected to the electric circuit on the circuit board 22. The current supplied from the external power supply flows to the coil 213 through the circuit board 22.

The resin casing 23 is a member made of resin that holds the stator 21 and the circuit board 22. The resin casing 23 is obtained by pouring resin into a cavity in a mold in which the stator 21 and the circuit board 22 are accommodated. That is, the resin casing 23 is a resin molded product having the stator 21 and the circuit board 22 as insert parts. Therefore, the stator 21 and the circuit board 22 are at least partially covered by the resin casing 23.

The resin casing 23 has a cylindrical portion 231 and a top plate portion 232. The cylindrical portion 231 extends in a substantially cylindrical shape in the axial direction. At least the core back 41 of the stator 21 is covered with a resin that constitutes the cylindrical portion 231. Further, a rotor 32 described later is disposed on the inner side in the radial direction of the cylindrical portion 231. The top plate portion 232 extends radially inward from the cylindrical portion 231 above the stator core 211 and the rotor 32 in the axial direction. At the center of the top plate portion 232, a circular hole 233 for passing a shaft 31 described later is provided.

The lower bearing portion 24 supports the shaft 31 rotatably below the rotor 32 in the axial direction. The upper bearing portion 25 rotatably supports the shaft 31 above the rotor 32 in the axial direction. The lower bearing portion 24 and the upper bearing portion 25 use ball bearings in which a plurality of balls intervene between the inner ring and the outer ring. The outer ring of the lower bearing portion 24 is fixed to the cylindrical portion 231 of the resin casing 23 via the lower cover member 241 made of metal. The outer ring of the upper bearing portion 25 is fixed to the top plate portion 232 of the resin casing 23 via the metal upper cover member 251. However, in place of the ball bearings, other types of bearings such as slide bearings or fluid bearings may be used.

The rotating portion 3 has a shaft 31 and a rotor 32. The shaft 31 is a cylindrical member extending in the axial direction. The shaft 31 is supported by the lower bearing portion 24 and the upper bearing portion 25 and rotates about the central axis 9. The upper end portion of the shaft 31 protrudes axially above the upper surface of the resin casing 23. At the upper end of the shaft 31, for example, a fan for an air conditioner is attached. However, the shaft 31 may be connected to a driving unit other than the fan via a power transmission mechanism such as a gear.

In addition, although the shaft 31 of this embodiment protrudes to the axial direction upper side of the resin casing 23, it is not limited to this. The shaft 31 may project downward in the axial direction of the resin casing 23, and the lower end portion of the shaft 31 may be connected to the drive unit. Further, the shaft 31 may protrude to both the upper side and the lower side in the axial direction of the resin casing 23, and both the upper end and the lower end thereof may be respectively connected to the driving portion.

The rotor 32 is fixed to the shaft 31 and rotates with the shaft 31. The rotor 32 has a rotor core 321 and a plurality of magnets 322. The rotor core 321 is formed of a laminated steel plate in which electromagnetic steel plates, which are magnetic bodies, are laminated in the axial direction. The plurality of magnets 322 are disposed on the outer peripheral surface of the rotor core 321. The radially outer surface of each magnet 322 is a magnetic pole surface that faces the radially inner end surface of the tooth 42 in the radial direction. In the plurality of magnets 322, the magnetic pole surfaces of the N pole and the magnetic pole surfaces of the S pole are alternately arranged, and are arranged at equal intervals in the circumferential direction.

The axial length of the magnet 322 is at least longer than the axial length of the stator core 211. The axial upper end of the magnet 322 is located above the axial upper end of the stator core 211. Further, the lower end in the axial direction of the magnet 322 is located below the lower end in the axial direction of the stator core 211. By making the length of the magnet 322 longer than that of the stator core 211, more magnetic flux can be taken into the stator core 211, and the efficiency of the motor 1 can be enhanced. In this case, at least one of the length from the upper end of stator core 211 to the upper end of magnet 322 and the length from the lower end of stator core 211 to the lower end of magnet 322 Is longer than the thickness of the nonmagnetic layer 40B.

In place of the plurality of magnets 322, a single annular magnet may be used. When an annular magnet is used, the N pole and the S pole may be alternately magnetized in the circumferential direction on the outer peripheral surface of the magnet. In addition, a part of the magnet may be embedded inside the rotor core. In addition, the magnet may be molded of a resin containing magnetic powder, and may be connected to the shaft 31.

When the motor 1 is driven, a drive current is supplied to the coil 213 via the circuit board 22. Then, magnetic flux is generated in the plurality of teeth 42 of stator core 211. Then, the action of the magnetic flux between the teeth 42 and the magnet 322 generates torque in the circumferential direction. As a result, the rotating portion 3 rotates around the central axis 9.

<2. About magnetic flux of stator core>
As described above, in the present embodiment, the stator core 211, specifically, the magnetic regions of the plurality of divided cores 40 are axially divided by the nonmagnetic layer 40B. In this case, more magnetic flux from the magnet 322 may be taken into the stator core 211 compared to a structure in which the stator core 211 is not divided by the nonmagnetic layer 40B under the condition that the axial length of the magnetic region of the stator core 211 is the same. it can. The magnetic flux from the magnet 322 to the stator core 211 will be described below.

FIG. 3 is a diagram for explaining the magnetic flux passing through the stator core 211. As shown in FIG. In FIG. 3, the magnetic flux is indicated by a broken arrow. Moreover, the core back 41 and the teeth 42 etc. which are shown in FIG. 3 are simplified and shown. FIG. 4 is a diagram showing the magnetic flux distribution of the stator core 211. As shown in FIG.

As described above, the magnet 322 protrudes in the axial direction above and below the teeth 42 in the axial direction. Hereinafter, the portion of the magnet 322 protruding upward from the teeth 42 in the axial direction is referred to as an upper overhang portion 322A. Further, the portion of the magnet 322 that protrudes below the teeth 42 is referred to as a lower overhang portion 322B. In addition, a portion of the magnet 322 that radially faces the nonmagnetic layer 40B is referred to as a central portion 322C.

A magnetic flux in the radial direction flows into the entire magnetic layer 40A from the magnet 322 facing in the radial direction. Further, the magnetic flux flows from the upper overhang portion 322A to the axially upper end portion of the magnetic layer 40A in the radially outward and downward sloping direction. Furthermore, the magnetic flux along the direction which inclines radially outward and upward from the central portion 322C flows into the axially lower end of the magnetic layer 40A.

Similarly, the magnetic flux in the radial direction flows from the magnet 322 facing in the radial direction into the entire magnetic layer 40C. Further, magnetic flux flows from the central portion 322C radially outward and downward to the upper end portion of the magnetic layer 40C in the axial direction. Furthermore, the magnetic flux along the direction which inclines radially outward and upward from the lower overhang part 322B flows into the lower end part in the axial direction of the magnetic layer 40C.

Hereinafter, the lower end in the axial direction of the magnetic layer 40A and the upper end in the axial direction of the magnetic layer 40C will be referred to as the central portion of the stator core 211.

As described above, in the axial direction, magnetic flux from a direction other than the radial direction (a direction inclined in the radial direction) flows into the upper end portion, the lower end portion, and the central portion of the stator core 211. Thereby, the amount of magnetic flux of the magnetic flux flowing into the upper end portion, the lower end portion, and the central portion of the stator core 211 becomes substantially the same. As a result, as shown in FIG. 4, in the axial direction, the magnetic flux density of the stator core 211 is substantially uniform in the region excluding the nonmagnetic layer 40B.

The magnetic flux density of the stator core 211 in the case where the nonmagnetic layer 40B is not provided will be described below for comparison with the present embodiment.

FIG. 5 is a diagram for explaining the magnetic flux passing through the stator core 211A in which the nonmagnetic layer is not provided. FIG. 6 is a diagram showing the magnetic flux distribution of the stator core 211A. The axial length of the magnetic region of the stator core 211A shown in FIG. 5 is the same as the magnetic region of the stator core 211 of the present embodiment.

The magnetic flux in the radial direction flows from the radially opposed magnets 322 into the entire stator core 211A. Further, the magnetic flux flows from the upper overhang portion 322A to the axially upper end portion of the stator core 211A in the radially outward and downward sloping direction. Furthermore, the magnetic flux along the direction which inclines radially outward and upward flows in from the lower overhang part 322B into the axial direction lower end part of the stator core 211A. Thereby, the amount of magnetic flux of the magnetic flux flowing into the upper end and the lower end of the stator core 211A becomes substantially the same. On the other hand, the amount of magnetic flux flowing into the central portion of the stator core 211A is smaller than the upper end and the lower end of the stator core 211A. As a result, as shown in FIG. 6, the magnetic flux density of the stator core 211A is biased in the axial direction.

FIG. 7 is a diagram showing a waveform of an induced voltage generated by the magnetic flux flowing into the stator core. 7, the induced voltage of the stator core 211 of the present embodiment provided with the nonmagnetic layer 40B is indicated by a solid line, and the induced voltage of the stator core 211A of FIG. 4 not provided with the nonmagnetic layer 40B is indicated by a broken line.

As shown in FIG. 7, the induced voltage of the stator core 211 provided with the nonmagnetic layer 40B is higher than the induced voltage of the stator core 211A not provided with the nonmagnetic layer 40B. That is, the amount of magnetic flux flowing into the stator core 211 is larger than that of the stator core 211A.

As described above, under the condition that the thickness of the laminated region of the magnetic region of the stator core is the same, the structure in which the magnetic region of the stator core is divided by the nonmagnetic layer 40B does not divide the magnetic region of the stator core by the nonmagnetic layer 40B. Compared to the structure, more magnetic flux from the magnet 322 can be taken. Thus, the stator core 211 can be effectively used as a magnetic path. As a result, the ratio of the output power to the input power of the motor 1 can be increased without increasing the product thickness of the magnetic region of the stator core 211, and the efficiency of the motor 1 can be improved.

In addition, by passing more magnetic flux to the stator core 211 and increasing the induced voltage, the number of turns of the coil 213 can be reduced. If the number of turns of the coil 213 is reduced, the thickness of the conductive wire of the coil 213 can be increased. As a result, copper loss in the conductor can be reduced, and efficiency can be improved.

<3. Modified example>
Although the exemplary embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

In the above embodiment, the magnetic region of the stator core 211 is divided into two by the nonmagnetic layer 40B, but may be divided into three or more regions as shown in FIG. FIG. 8 is a diagram for explaining the magnetic flux passing through the stator core 211B in which the magnetic region is divided into three by the two nonmagnetic layers 40B. In this case, the stator core 211 has an increased number of surfaces for taking in the magnetic flux in the axial direction. Therefore, more magnetic flux can be taken in.

FIG. 9 is a diagram showing the waveform of the induced voltage of the stator core according to the difference in the number of nonmagnetic layers 40B. In FIG. 9, the nonmagnetic layer 40B shows the voltage waveform of the two stator cores 211B by a broken line, and the nonmagnetic layer 40B shows the voltage waveform of one stator core 211 by a broken line. As shown in FIG. 9, in the case of a structure in which the number of nonmagnetic layers 40B is large and the magnetic region of the stator core is further divided, a higher induced voltage can be obtained.

Moreover, in the said embodiment, although the nonmagnetic layer 40B is provided in the position which bisects the magnetic area | region of the stator core 211 to an axial direction, it is not limited to this. For example, the axial length of the magnetic layer 40A may be longer than the axial length of the magnetic layer 40C, or vice versa. However, if the axial length of the magnetic layer 40A or the magnetic layer 40C is too small, the region to be the magnetic path in the magnetic layer becomes narrow, and the magnetic flux hardly flows. Therefore, the axial length of at least one of the plurality of

magnetic layers

40A and 40C of the stator core 211 is preferably longer than the thickness of the nonmagnetic layer 40B.

In the above embodiment, at least one of the length from the upper end of the stator core 211 to the upper end of the magnet 322 and the length from the lower end of the stator core 211 to the lower end of the magnet 322 is , And the thickness of the nonmagnetic layer 40B. Thereby, the magnetic flux density of stator core 211 can be further raised. However, the thickness of the nonmagnetic layer 40B is not limited to this.

The stator core 211 may have a structure that can be separated in the axial direction up and down. FIG. 10 shows the separable stator core 211. As shown in FIG. The nonmagnetic layer 40B is formed by laminating a first layer 40B1 and a second layer 40B2. The stator core 211 can be separated vertically in the axial direction as shown in FIG. 9 at the boundary between the first layer 40B1 and the second layer 40B2. In this configuration, in the case of providing a nonmagnetic layer at the same time as attaching two stator cores separated vertically, it is difficult to position the stator core with a mold or jig. On the other hand, as shown in FIG. 9, by providing the nonmagnetic layer on both of the two separate stator cores, the nonmagnetic layer 40B is formed by attaching the two stator cores. Positioning of the stator core during formation is facilitated. In addition, after two separate stator cores are attached, the conducting wire is wound around the teeth 42, and the coil 213 is provided.

The present invention is applicable to stators and motors.

1: Motor 2: Static part 3: Rotating part 9: Center axis 21: Stator core 22: Circuit board 23: Resin casing 24: Lower bearing 25: Upper bearing 31: Shaft 32: Rotor 40: Divided core 40A: Magnetic layer 40B: nonmagnetic layer 40B1: first layer 40B2: second layer 40C: magnetic layer 41: core back 42: core 51: teeth insulating portion 52: upper side wall 53: lower side wall 211: stator core 211A: stator core 211B: stator core 212: insulator 213: coil 231: cylindrical portion 232: top plate portion 233: circular hole 241: lower cover member 251: upper cover member 321: rotor core 322: magnet 322A: upper overhang portion 322B: lower overhang portion 322C: Center

Claims

The stator of the motor,
A stator core of a magnetic body having an annular core back surrounding a vertically extending central axis, and a plurality of teeth radially extending from the core back;
A resin insulator covering at least a part of the teeth;
A coil made of a conducting wire wound on the teeth via the insulator;
Equipped with
The stator core is
Divided into a plurality of regions in the axial direction by interposing an insulator that is nonmagnetic and electrically insulating
Stator.
The stator according to claim 1, wherein
The insulator is a resin material,
Stator.
The stator according to claim 1 or 2, wherein
The stator core includes a plurality of the insulators and is divided into three or more regions by the plurality of insulators.
Stator.
A motor comprising the stator according to any one of claims 1 to 3,
A rotor rotating about a central axis,
The rotor has a magnet at a position facing the stator core,
The axial length of the magnet is longer than the axial length of the stator core,
The axial upper end of the magnet is positioned above the axial upper end of the stator core,
An axially lower end of the magnet is positioned lower than an axially lower end of the stator core.
motor.
The motor according to claim 4, wherein
At least one of a length from the upper end of the stator core to the upper end of the magnet and a length from the lower end of the stator core to the lower end of the magnet is Longer than the thickness of the insulator,
motor.
The motor according to claim 4 or 5, wherein
The axial length of at least one of the plurality of regions of the stator core is greater than the thickness of the insulator,
motor.
A motor according to any one of claims 4 to 6, wherein
The insulator and the insulator are the same member,
motor.
The motor according to claim 7, wherein
The insulator has a first layer and a second layer extending in the axial direction,
The stator core is
The axial direction is separated at the boundary between the first layer and the second layer,
motor.