JPWO2019008930A1 - Stator and motor - Google Patents

Abstract

A stator of a motor includes 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, and a resin insulator covering at least a part of the teeth. And a coil made of a conductor wire wound around the tooth via an insulator. The stator core is divided into a plurality of regions in the axial direction by interposing a non-magnetic and electrically insulating non-magnetic layer.

Description

  The present invention relates to a stator and a motor.

Japanese Unexamined Patent Application Publication No. 2002-101583 discloses an electric motor that detects the position of a rotor core. In the electric motor described in the publication, a position detecting element is arranged at a position facing in the axial direction of the rotor, and the magnetic flux from the magnet of the rotor is passed through the position detecting element to detect the position. In addition, 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 rotating shaft is increased.
JP 2002-101583 A

  In the electric motor having the structure described in JP-A-2002-101583, if more magnetic flux from the magnet can be taken in by 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 electric motor can be increased, and the efficiency of the motor can be improved. Therefore, it is desired to increase the magnetic flux taken into the stator core.

  An object of the present invention is to provide a stator core and a motor that can take in more magnetic flux from a magnet into the stator core without increasing 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 conductive wire wound around the teeth via the insulator are provided, and the stator core includes an insulator that is nonmagnetic and electrically insulating. By doing so, it is divided into a plurality of regions in the axial direction.

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

FIG. 1 is a vertical sectional view of a motor. FIG. 2 is a perspective view of a stator core included in the stator. FIG. 3 is a diagram for explaining a magnetic flux passing through the stator core. FIG. 4 is a diagram showing a magnetic flux distribution of the stator core. FIG. 5 is a diagram for explaining a magnetic flux passing through a stator core having no non-magnetic layer. FIG. 6 is a diagram showing a magnetic flux distribution of the stator core. FIG. 7: is a figure which shows the waveform of the induced voltage produced when a magnetic flux flows into a stator core. FIG. 8 is a diagram for explaining a magnetic flux passing through a stator core in which a magnetic region is divided into three by two nonmagnetic layers. FIG. 9 is a diagram showing the waveform of the induced voltage in the stator core depending on 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 orthogonal 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, this definition of the vertical direction is not intended to limit the orientation of the motor according to the present invention during manufacture and during use.

<1. Overall configuration of motor>
FIG. 1 is a vertical sectional view of the motor 1. The motor 1 is used for home appliances such as air conditioners. However, the motor 1 may be used for purposes other than home appliances. For example, the motor 1 may be mounted in a transportation device such as an automobile or a railroad, an OA device, a medical device, a tool, a large-scale industrial facility, or the like to generate various driving forces.

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

  The stationary portion 2 has 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 a 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 the stator core 211 included in the stator 21. The stator core 211 shown in FIG. 2 is in a state cut along 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 split cores 40. The plurality of split cores 40 are arranged in the circumferential direction. Each split core 40 has a core back 41 and a tooth 42. When the plurality of core backs 41 are in contact with each other, the core backs 41 as a whole have an annular shape centered on the central axis 9. The teeth 42 extend radially inward from the core back 41.

  The split core 40 is configured by laminating a magnetic layer 40A, a non-magnetic layer 40B, and a magnetic layer 40C in the axial direction. The magnetic layers 40A and 40C are formed by laminating electromagnetic steel sheets, for example. The nonmagnetic layer 40B is, for example, an insulator made of a resin material that is nonmagnetic and electrically insulating. The magnetic layer 40A is stacked axially above the non-magnetic layer 40B, and the magnetic layer 40C is stacked axially below the non-magnetic 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 a continuous annular core.

  In the present embodiment, the non-magnetic layer 40B evenly divides the magnetic region of the split core 40. Therefore, the two magnetic layers 40A and 40C have the same axial length. The nonmagnetic layer 40B is arranged at the center of the tooth 42 in the axial direction.

  The insulator 212 is attached to the stator core 211. The insulator 212 is made of resin, which is an insulator. The insulator 212 has a tooth insulating portion 51 that covers both axial end surfaces and both circumferential surfaces of each tooth 42. The coil 213 is composed of a conductor wire wound around the tooth insulating portion 51. That is, the conductive wire forming the coil 213 is wound around the tooth 42 via the tooth insulating portion 51 of the insulator 212.

  The insulator 212 has an upper side wall portion 52. The upper side wall portion 52 extends from both ends on the radially inner side and the outer side of the tooth insulating portion 51 toward both sides in the axial upper side and the circumferential direction. Further, the insulator 212 has a lower side wall portion 53. The lower side wall portion 53 extends from the inner and outer ends of the tooth insulating portion 51 in the radial direction toward the axial lower side and the circumferential both sides. The upper side wall portion 52 and the lower side wall portion 53 suppress the collapse of the coil 213 and prevent the conductive wire forming 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 different member from the nonmagnetic layer 40B.

  The circuit board 22 is located on the axial upper side of the stator 21 and is arranged substantially perpendicular to the central axis 9. The circuit board 22 is fixed to the upper end of the insulator 212 by, for example, welding. An electric circuit for supplying a drive current to the coil 213 is mounted on the circuit board 22. The ends of the conductors forming the coil 213 are electrically connected to the electric circuit on the circuit board 22. The current supplied from the external power source flows to the coil 213 via the circuit board 22.

  The resin casing 23 is a resin member that holds the stator 21 and the circuit board 22. The resin casing 23 is obtained by pouring a resin into a cavity in a mold that houses the stator 21 and the circuit board 22. That is, the resin casing 23 is a resin molded product that uses 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 with the resin casing 23.

  The resin casing 23 has a cylindrical portion 231 and a top plate 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 the resin forming the cylindrical portion 231. A rotor 32, which will be described later, is arranged inside the cylindrical portion 231 in the radial direction. 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. A circular hole 233 is provided in the center of the top plate 232 for passing a shaft 31 described later.

  The lower bearing portion 24 rotatably supports the shaft 31 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. For the lower bearing portion 24 and the upper bearing portion 25, ball bearings in which a plurality of spherical bodies are interposed between an inner ring and an outer ring are used. The outer ring of the lower bearing portion 24 is fixed to the cylindrical portion 231 of the resin casing 23 via a metal lower cover member 241. 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, instead of the ball bearing, another type of bearing such as a slide bearing or a fluid bearing may be used.

  The rotating unit 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 of the shaft 31 projects axially above the upper surface of the resin casing 23. A fan for an air conditioner is attached to the upper end of the shaft 31, for example. However, the shaft 31 may be connected to a drive unit other than the fan via a power transmission mechanism such as a gear.

  Although the shaft 31 of the present embodiment projects upward in the axial direction of the resin casing 23, the present invention 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 thereof may be connected to the drive portion. Further, the shaft 31 may project to both the axial upper side and the axial lower side of the resin casing 23, and both the upper end portion and the lower end portion thereof may be connected to the drive portion, respectively.

  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 made of laminated steel sheets in which magnetic steel sheets that are magnetic bodies are laminated in the axial direction. The plurality of magnets 322 are arranged on the outer peripheral surface of the rotor core 321. The radially outer surface of each magnet 322 is a magnetic pole surface that radially faces the radially inner end surface of the tooth 42. The plurality of magnets 322 have N-pole magnetic pole surfaces and S-pole magnetic pole surfaces alternately arranged and 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 upper end of the magnet 322 in the axial direction is located above the upper end of the stator core 211 in the axial direction. In addition, the lower end of the magnet 322 in the axial direction is located below the lower end of the stator core 211 in the axial direction. 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 improved. In this case, 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 longer than the thickness of the nonmagnetic layer 40B.

  In addition, instead of the plurality of magnets 322, a single annular magnet may be used. When using an annular magnet, the N pole and the S pole may be magnetized alternately in the circumferential direction on the outer peripheral surface of the magnet. Further, a part of the magnet may be embedded inside the rotor core. Further, the magnet may be molded from 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 the stator core 211. Then, due to the action of the magnetic flux between the teeth 42 and the magnet 322, circumferential torque is generated. As a result, the rotating unit 3 rotates about the central axis 9.

<2. About the magnetic flux of the stator core>
As described above, in the present embodiment, the stator core 211, specifically, the magnetic regions of each of the plurality of split cores 40 are axially split by the non-magnetic layer 40B. In this case, more magnetic flux from the magnet 322 can be taken into the stator core 211 as compared with a structure in which the stator core 211 is not divided by the nonmagnetic layer 40B under the condition that the magnetic regions of the stator core 211 have the same axial length. 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. In FIG. 3, the magnetic flux is indicated by a dashed arrow. Further, the core back 41, the teeth 42 and the like shown in FIG. 3 are shown in a simplified manner. FIG. 4 is a diagram showing a magnetic flux distribution of the stator core 211.

  As described above, the magnet 322 projects in the axial direction vertically above the teeth 42. Hereinafter, the portion of the magnet 322 protruding above the tooth 42 in the axial direction will be referred to as an upper overhang portion 322A. Further, the portion of the magnet 322 protruding below the teeth 42 is referred to as a lower overhang portion 322B. The portion of the magnet 322 that faces the nonmagnetic layer 40B in the radial direction is referred to as the central portion 322C.

  A magnetic flux along the radial direction flows into the entire magnetic layer 40A from the magnets 322 facing each other in the radial direction. Further, a magnetic flux flows in the axially upper end portion of the magnetic layer 40A from the upper overhang portion 322A along the direction inclined radially outward and downward. Further, magnetic flux flows in the axially lower end portion of the magnetic layer 40A from the central portion 322C along the direction inclined radially outward and upward.

  Similarly, a magnetic flux along the radial direction flows into the entire magnetic layer 40C from the magnets 322 facing each other in the radial direction. In addition, a magnetic flux flows in the axially upper end portion of the magnetic layer 40C from the central portion 322C along the direction inclined radially outward and downward. Further, magnetic flux flows in the axially lower end portion of the magnetic layer 40C from the lower overhang portion 322B along the direction inclined radially outward and upward.

  Hereinafter, the axially lower end portion of the magnetic layer 40A and the axially upper end portion of the magnetic layer 40C are referred to as the central portion of the stator core 211.

  Thus, in the axial direction, magnetic flux from a direction other than the radial direction (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. As a result, the amount of 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 becomes substantially uniform in the region excluding the nonmagnetic layer 40B.

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

  FIG. 5 is a diagram for explaining a magnetic flux passing through the stator core 211A having no non-magnetic layer. FIG. 6 is a diagram showing a 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 this embodiment.

  A magnetic flux along the radial direction flows into the entire stator core 211A from the magnets 322 facing each other in the radial direction. Further, a magnetic flux flows in the axially upper end portion of the stator core 211A from the upper overhang portion 322A in a direction that is inclined radially outward and downward. Further, magnetic flux flows in the axially lower end portion of the stator core 211A from the lower overhang portion 322B along the direction inclined outward in the radial direction and upward. As a result, the amount of magnetic flux flowing into the upper end portion and the lower end portion of the stator core 211A becomes substantially the same. On the other hand, the magnetic flux amount of the magnetic flux flowing into the central portion of the stator core 211A is smaller than the upper end portion and the lower end portion 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 figure which shows the waveform of the induced voltage produced when a magnetic flux flows into a stator core. In FIG. 7, the induced voltage of the stator core 211 of the present embodiment provided with the non-magnetic layer 40B is shown by a solid line, and the induced voltage of the stator core 211A of FIG. 4 without the non-magnetic layer 40B is shown 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 laminated thickness of the magnetic region of the stator core is the same, the magnetic region of the stator core is not divided by the nonmagnetic layer 40B in the structure in which the magnetic region of the stator core is divided by the nonmagnetic layer 40B. As compared with the structure, more magnetic flux from the magnet 322 can be taken in. Thereby, 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 and the efficiency of the motor 1 can be improved without increasing the product thickness length of the magnetic region of the stator core 211.

  Further, since more magnetic flux can be passed through the stator core 211 to increase the induced voltage, the number of turns of the coil 213 can be reduced. By reducing the number of turns of the coil 213, the conductor wire of the coil 213 can be thickened. As a result, copper loss in the conductive wire can be reduced and efficiency can be improved.

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

  In the above embodiment, the magnetic region of the stator core 211 is divided into two by the nonmagnetic layer 40B, but as shown in FIG. 8, it may be divided into three or more regions. FIG. 8 is a diagram for explaining a 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 more surfaces for taking in 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 in the stator core depending on the number of nonmagnetic layers 40B. In FIG. 9, the non-magnetic layer 40B shows the voltage waveforms of the two stator cores 211B by broken lines, and the non-magnetic layer 40B shows the voltage waveform of one stator core 211 by broken lines. As shown in FIG. 9, a structure in which the number of the non-magnetic layers 40B is large and the magnetic region of the stator core is divided into a larger number can obtain a higher induced voltage.

  Further, in the above-described embodiment, the nonmagnetic layer 40B is provided at a position that bisects the magnetic region of the stator core 211 in the axial direction, but 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, when the axial length of the magnetic layer 40A or the magnetic layer 40C is too small, the region serving as the magnetic path in the magnetic layer becomes narrow, and it becomes difficult for the magnetic flux to flow. Therefore, the axial length of at least one of the 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 at least one. , Longer than the thickness of the non-magnetic layer 40B. As a result, the magnetic flux density of the stator core 211 can be further increased. However, the thickness of the nonmagnetic layer 40B is not limited to this.

  In addition, the stator core 211 may have a structure that can be vertically separated in the axial direction. FIG. 10 is a view showing the separable stator core 211. The nonmagnetic layer 40B is formed by laminating a first layer 40B1 and a second layer 40B2. Then, the stator core 211 can be separated vertically in the axial direction with the boundary between the first layer 40B1 and the second layer 40B2 as shown in FIG. In this configuration, in the case of mounting the two stator cores that are separated vertically from each other and providing the non-magnetic layer at the same time, it is difficult to position the stator core with a mold or a jig. On the other hand, as shown in FIG. 9, by providing the non-magnetic layer on both of the two separated stator cores, the non-magnetic layer 40B is formed by attaching the two stator cores. Positioning of the stator core during formation is facilitated. After the two separated stator cores are attached, a conductive wire is wound around the tooth 42 to provide the coil 213.

  INDUSTRIAL APPLICATION This invention can be utilized for a stator and a motor.

1: Motor 2: Static part 3: Rotating part 9: Central shaft 21: Stator core 22: Circuit board 23: Resin casing 24: Lower bearing part 25: Upper bearing part 31: Shaft 32: Rotor 40: Split core 40A: Magnetic layer 40B: non-magnetic layer 40B1: first layer 40B2: second layer 40C: magnetic layer 41: core back 42: teeth 51: teeth insulating part 52: upper side wall part 53: lower side wall part 211: stator core 211A: stator core 211B: stator core 212: Insulator 213: Coil 231: Cylindrical part 232: Top plate part 233: Circular hole 241, Lower cover member 251, Upper cover member 321, Rotor core 322: Magnet 322A: Upper overhang part 322B: Lower overhang part 322C: Center

Claims (8)

A motor stator,
A magnetic stator core having an annular core back surrounding a vertically extending central axis and a plurality of teeth extending radially from the core back;
A resin insulator covering at least a part of the teeth,
A coil made of a conductive wire wound around the teeth via the insulator,
Equipped with
The stator core is
By interposing an insulator that is non-magnetic and electrically insulating, it is divided into a plurality of regions in the axial direction,
Stator. The stator according to claim 1,
The insulator is a resin material,
Stator. It is a stator of Claim 1 or Claim 2, Comprising:
The stator core has a plurality of the insulators, and is divided into three or more regions by the plurality of insulators.
Stator. A motor having the stator according to claim 1,
A rotor that rotates 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 located above the axial upper end of the stator core,
An axial lower end of the magnet is located lower than an axial lower end of the stator core,
motor. The motor according to claim 4, wherein
At least one of the length from the upper end of the stator core to the upper end of the magnet, and the length from the lower end of the stator core to the lower end of the magnet, Longer than the thickness of the insulator,
motor. The motor according to claim 4 or claim 5,
The axial length of at least one of the plurality of regions of the stator core is longer than the thickness of the insulator,
motor. The motor according to any one of claims 4 to 6,
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
With the boundary between the first layer and the second layer as a boundary, the layers are separated in the axial direction,
motor.