TW201639275A - Motor - Google Patents

Abstract

The present invention provides a motor. One embodiment of the motor includes: a shaft that centers a center axis extending in the vertical direction; an upper rotor and a lower rotor installed on the shaft separated by a specified interval along the axis; a stator disposed between the upper rotor and the lower rotor; and a bearing that bears the shaft. The upper rotor and the lower rotor include magnets axially opposite to the stator. With respect to the magnet poles, N and S poles are alternately arranged in the circumferential direction. The shaft, the upper rotor and the lower rotor are provided with an engaging structure. The engaging structure determines the relative position of the shaft and the upper rotor in the circumferential direction, and determines the relative position of the shaft and the lower rotor in the circumferential direction.

Description

motor Technical field

The invention relates to a motor.

Background technique

An axial gap type motor in which a pair of rotors having permanent magnets face each other is described in Japanese Laid-Open Patent Publication No. 2006-288012.

In the axial gap type motor described above, there is a concern that if the relative position of the pair of rotors in the circumferential direction deviates from the design value, the magnetic field generated between the rotors becomes unbalanced in the circumferential direction, and the rotor generates vibration and noise. . Further, there is also a concern that the axial gap type motor does not have a desired rotational torque.

Further, in the axial gap type motor described above, for example, in order to reduce the torque ripple of the electric motor and the cogging torque, the pair of rotors may be arranged to be shifted in the circumferential direction. In this case, there is a concern that if the relative position of the pair of rotors in the circumferential direction deviates from the design value, the torque ripple and the cogging torque cannot be sufficiently reduced. Further, there is also a concern that the vibration and noise of the rotor described above are deteriorated.

Therefore, in an axial gap type motor having a pair of rotors, A structure capable of positioning the relative positions of a pair of rotors in the circumferential direction with high precision and ease is required.

Summary of invention

In view of the above problems, an object of one embodiment of the present invention is to provide a motor having a structure capable of accurately positioning the relative positions of two rotors in the circumferential direction with high precision.

One embodiment of the motor of the present invention has a shaft centered on a central axis extending in the up and down direction, an upper rotor and a lower rotor, a stator, and a bearing that supports the shaft. The upper rotor and the lower rotor are attached to the shaft at predetermined intervals in the axial direction. The stator is disposed between the upper rotor and the lower rotor.

The upper rotor and the lower rotor have magnets that oppose the stator in the axial direction. Regarding the magnetic pole of the magnet, the N pole and the S pole are alternately arranged in the circumferential direction. A fitting structure is provided in the shaft, the upper rotor, and the lower rotor. The fitting structure determines the relative position of the shaft and the upper rotor in the circumferential direction, and determines the relative position of the shaft and the lower rotor in the circumferential direction.

According to the motor of one embodiment of the present invention, the relative positions of the two rotors in the circumferential direction can be accurately and easily positioned.

10‧‧‧ motor

11‧‧‧Shell

12‧‧‧Intermediate casing

12a‧‧‧ openings

13‧‧‧Lower case

13a‧‧‧Tube

13b‧‧‧ bottom wall

14‧‧‧Upper casing

15‧‧‧Bottom bearing retaining section

15a‧‧‧ Output shaft hole

20, 120‧‧‧ axis

21‧‧‧Upper rotor fitting part (fitting part)

21a‧‧‧Upper shaft side keyway section (shaft side keyway section)

22‧‧‧Upper bearing fitting part (fitting part)

23‧‧‧Upper bearing support

24‧‧‧Maximum OD

24a‧‧‧Maximum outer diameter lower surface

25, 125‧‧‧ lower rotor fitting part (fitting part)

25a, 125a‧‧‧ Lower shaft side key groove (shaft side key groove)

26‧‧‧Removal-proof part fitting part (fitting part)

27‧‧‧Bottom bearing fitting part (fitting part)

28‧‧‧ Output shaft

31‧‧‧Upper rotor

32, 232‧‧‧ lower rotor

33, 33N, 33S‧‧‧ upper magnet

34‧‧‧Upper rotor body

34a‧‧‧Upper plate (board)

34b‧‧‧Upper tubular part (cylindrical part)

34c‧‧‧Upper rotor hole (rotor hole)

34d‧‧‧Upper rotor side keyway (rotor side keyway)

35, 35N, 35S‧‧‧ lower magnet

36, 236‧‧‧ lower rotor body

36a‧‧‧Bottom plate (plate)

36b‧‧‧Bottom cylindrical part (cylindrical part)

36c‧‧‧Bottom rotor hole (rotor hole)

36d‧‧‧ Lower rotor side keyway (rotor side keyway)

36e‧‧‧ Upper rotor upper surface

37‧‧‧Upside chimeric structure

38, 238‧‧‧ underside chiseling structure

39‧‧‧Chimeric structure

40‧‧‧ Stator

41‧‧‧ iron core

42‧‧‧ coil

42a‧‧‧Coil lead wire

43‧‧‧Insulation

44‧‧‧Upper bearing cage

44e‧‧‧The inner circumference of the cage

45‧‧‧ Cover

45a‧‧ hood tube

45b‧‧‧ Cover flange

46‧‧‧Molded resin department

51‧‧‧Upper bearing

52‧‧‧Bottom bearing

60, 61‧‧‧ key components

70‧‧‧ Bus bar unit

71‧‧‧Connector

80‧‧‧Removal parts

236d‧‧‧ convex

BP1‧‧‧Upper rotor reference position (reference position)

BP2‧‧‧ lower rotor reference position (reference position)

J‧‧‧ central axis

P1‧‧‧Upper circumferential center

P2‧‧‧ lower circumferential center

P3‧‧‧ convex center

SL1‧‧‧first radial line

SL2‧‧‧second radial line

SL3‧‧‧ third radial line

Fig. 1 is a cross-sectional view showing a motor of a first embodiment.

Fig. 2 is a cross-sectional view showing a part of the motor of the first embodiment.

Fig. 3 is a side view showing the shaft of the first embodiment.

Fig. 4 is a plan view showing the upper rotor of the first embodiment.

Fig. 5 is a plan view showing the lower rotor of the first embodiment.

Fig. 6 is a side view showing another example of the shaft of the first embodiment.

Fig. 7 is a cross-sectional view showing the lower rotor of the second embodiment.

detailed description

Hereinafter, a motor according to a preferred embodiment of the present invention will be described with reference to the drawings. Further, the scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention. In addition, in the following drawings, in order to make it easy to understand each structure, the scale and number of each structure may differ from the scale and number of actual structures.

Further, in the drawings, the XYZ coordinate system is appropriately shown as a three-dimensional Cartesian coordinate system. In the XYZ coordinate system, the Z-axis direction is a direction parallel to the axial direction of the central axis J shown in FIG. The X-axis direction is a direction orthogonal to the Z-axis direction and is the left-right direction of FIG. The Y-axis direction is a direction orthogonal to the X-axis direction and the Z-axis direction.

Further, in the following description, the extending direction (Z-axis direction) of the central axis J is the vertical direction. The positive side (+Z side) in the Z-axis direction is referred to as "upper side", and the negative side (-Z side) in the Z-axis direction is referred to as "lower side". In addition, the up-and-down direction, the upper side, and the lower side are names used only for the description, and the actual positional relationship and direction are not limited. Further, unless otherwise specified, a direction parallel to the central axis J (Z-axis direction) or a direction substantially parallel is simply referred to as "axial direction", and a radial direction centered on the central axis J is simply referred to as "radial direction". The circumferential direction (θ _Z direction) centering on the central axis J, that is, the direction around the central axis J is simply referred to as "circumferential direction".

In addition, in the present specification, the term "extending in the axial direction" means extending in a direction inclined in a range of less than 45 degrees with respect to the axial direction, in addition to the case of strictly extending in the axial direction. Further, in the present specification, the term "extending in the radial direction" includes, in addition to the case of strictly extending in the radial direction, that is, in the direction perpendicular to the axial direction, the direction of inclination in a range of less than 45 degrees with respect to the radial direction. The situation of the extension.

FIG. 1 is a cross-sectional view showing a motor 10 of a first embodiment. Motor 10 is an axial gap motor. As shown in FIG. 1, the motor 10 has a casing 11, a shaft 20, an upper rotor 31 and a lower rotor 32 which are two rotors, an upper bearing 51, a lower bearing 52, a stator 40, a bus bar unit 70, and a connector 71. .

The casing 11 is a motor housing of the motor 10. The casing 11 is made of, for example, metal or resin. The casing 11 houses the shaft 20, the upper rotor 31, the lower rotor 32, the stator 40, the upper bearing 51, the lower bearing 52, and the bus bar unit 70. The casing 11 has an intermediate casing 12, a lower casing 13, and an upper casing 14. The lower rotor 32 is located radially inward of the cylindrical intermediate casing 12. A cylindrical lower casing 13 is attached to the lower side of the intermediate casing 12. The lower casing 13 has a bottom wall portion 13b, a tubular portion 13a, and a lower bearing holding portion 15.

The bottom wall portion 13b has an annular shape that surrounds the shaft 20 in the circumferential direction. The tubular portion 13a extends from the outer peripheral end of the bottom wall portion 13b to the upper side. The upper end of the tubular portion 13a is fitted to the lower opening portion 12a of the intermediate casing 12. The lower bearing holding portion 15 is located on the radially inner side of the bottom wall portion 13b. The lower bearing holding portion 15 holds the lower bearing 52. The lower bearing holding portion 15 has an output shaft hole 15a that is open at the lower side.

The cylindrical upper casing 14 is passed through a cover flange of a cover 45 to be described later. The portion 45b is mounted on the upper side of the intermediate casing 12. The upper rotor 31, the stator 40, and the bus bar unit 70 are located radially inward of the upper casing 14.

Further, in the present specification, the motor casing is, for example, a component that accommodates and protects a space of a rotor, a stator, and a drive component such as a shaft in contact with a space outside the motor.

The shaft 20 is centered on a central axis J extending in the up and down direction. The shaft 20 is supported by the upper bearing 51 and the lower bearing 52 so as to be rotatable about the central axis J. That is, the upper bearing 51 and the lower bearing 52 are bearings that support the shaft 20 . The lower end of the shaft 20 protrudes to the outside of the casing 11 via the output shaft hole 15a.

The upper rotor 31 and the lower rotor 32 are attached to the shaft 20 at a predetermined interval in the axial direction. The upper rotor 31 is located on the upper side of the stator 40. The upper rotor 31 has an upper rotor main body 34 and a plurality of upper magnets 33.

The upper rotor main body 34 is, for example, in the shape of a disk extending in the radial direction. The upper rotor main body 34 is fixed to the upper end of the shaft 20. The upper magnet 33 is fixed to the lower surface of the upper rotor main body 34. Although not shown in the drawings, the plurality of upper magnets 33 are arranged in the circumferential direction. Regarding the magnetic poles of the upper magnet 33, the N pole and the S pole are alternately arranged in the circumferential direction. The upper magnet 33 and the stator 40 face each other with a gap in the axial direction.

The lower rotor 32 is located on the lower side of the stator 40. The lower rotor 32 has a disc-shaped lower rotor main body 36 and a plurality of lower magnets 35 extending in the radial direction. The lower rotor main body 36 is fixed to the shaft 20. The lower magnet 35 is fixed to the upper surface of the lower rotor main body 36. The plurality of lower magnets 35 are arranged in the circumferential direction. Regarding the magnetic poles of the lower magnet 35, the N pole and the S pole are alternately arranged in the circumferential direction. The lower magnet 35 and the stator 40 face each other with a gap in the axial direction. Upper magnet 33 and lower magnet The irons 35 are axially opposed to each other with different poles. Thereby, the rotational torque can be obtained by the upper rotor 31 and the lower rotor 32, and thus the rotational torque of the motor 10 can be increased.

The stator 40 is disposed between the two rotors, that is, between the upper rotor 31 and the lower rotor 32. The stator 40 has a plurality of cores 41, a coil 42, an insulator 43, an upper bearing holder 44, a cover 45, and a molded resin portion 46. The stator 40 is, for example, a molded product. The plurality of cores 41 are arranged in the circumferential direction. The plurality of cores 41 are located between the upper bearing cage 44 and the cover 45 in the radial direction. For example, a plurality of iron cores 41 are provided in twelve.

A bobbin-shaped insulating member 43 is attached to the iron core 41. The insulating member 43 is, for example, a member molded by a resin material. The coil 42 is wound around the iron core 41 via the insulating member 43. The coil 42 has a coil lead wire 42a. The coil 42 excites the iron core 41.

The coil lead wire 42a is taken out from the coil 42 to the upper side. The coil lead wire 42a extends upward from the iron core 41. The coil lead wire 42a is electrically connected to the bus bar of the bus bar unit 70. The coil lead wire 42a may be a part of the winding constituting the coil 42, or may be a member separate from the winding constituting the coil 42.

The cylindrical upper bearing holder 44 holds the upper bearing 51. The upper bearing cage 44 is located radially inward of the plurality of cores 41 and radially outward of the shaft 20. The upper bearing holder 44 is, for example, a cylindrical shape concentric with the center axis J. The upper bearing 51 is held by the holder inner circumferential surface 44e which is the inner circumferential surface of the upper bearing holder 44.

The cylindrical cover 45 is disposed on the radially outer side of the plurality of cores 41. Cover 45 The cover cylindrical portion 45a and the cover flange portion 45b are provided. The cover cylindrical portion 45a extends in the axial direction and is open at both axial ends. The cover cylindrical portion 45a is, for example, a cylindrical shape concentric with the central axis J.

The cover flange portion 45b extends radially outward from the lower end of the cover cylindrical portion 45a. The lower surface of the cover flange portion 45b is in contact with the upper surface of the intermediate casing 12. The upper surface of the cover flange portion 45b is in contact with the lower surface of the upper casing 14. The cover flange portion 45b is fixed to the casing 11 by, for example, a screw. Thereby, the stator 40 is fixed to the casing 11. The radially outer end surface of the cover flange portion 45b is exposed to the outside of the motor 10.

The molded resin portion 46 is located between the respective components constituting the stator 40. The molded resin portion 46 is located, for example, between the coil 42 and the insulating member 43, the upper bearing holder 44, and the cover 45 in the radial direction.

The bus bar unit 70 is located on the upper side of the upper rotor 31. A coil lead line 42a is connected to the bus bar unit 70. The bus bar unit 70 holds a bus bar (not shown). The bus bar is electrically connected to the coil lead line 42a. One end of the bus bar is exposed to the outside of the casing 11 via the connector 71. The motor 10 also has a retaining member 80. The retaining member 80 is fixed to the shaft 20.

Next, the shaft 20 will be described in detail. Fig. 2 is a partial enlarged view of Fig. 1; FIG. 3 is a side view (YZ plane view) showing the shaft 20. As shown in FIGS. 1 to 3, in the present embodiment, the shaft 20 has a plurality of portions having different diameters.

As shown in FIG. 1, the shaft 20 has an upper rotor fitting portion (fitting portion) 21, an upper bearing fitting portion (fitting portion) 22, and an upper bearing support portion 23 in this order from the upper end portion toward the lower end portion. , the largest outer diameter portion 24, the lower side rotor embedded A joint portion (fitting portion) 25, a retaining member fitting portion (fitting portion) 26, a lower bearing fitting portion (fitting portion) 27, and an output shaft portion 28.

The upper rotor fitting portion 21, the upper bearing fitting portion 22, the lower rotor fitting portion 25, the retaining member fitting portion 26, and the lower bearing fitting portion 27 are fitting portions to which other components are fitted. That is, the shaft 20 has a plurality of fitting portions into which other components are fitted.

The upper rotor 31 is fitted to the upper rotor fitting portion 21. The upper bearing 51 is fitted to the upper bearing fitting portion 22. The lower rotor 32 is fitted to the lower rotor fitting portion 25. The retaining member 80 is fitted to the retaining member fitting portion 26. A lower bearing 52 is fitted to the lower bearing fitting portion 27 .

The largest outer diameter portion 24 is the portion of the shaft 20 having the largest diameter. The maximum outer diameter portion 24 is located between the upper rotor 31 and the lower rotor 32 in the axial direction. As shown in Fig. 2, the maximum outer diameter portion lower surface 24a of the surface on the lower side in the axial direction of the maximum outer diameter portion 24 and the lower outer surface of the surface on the maximum outer diameter portion 24 side (+Z side) of the lower rotor 32 are shown. The upper surface 36e is in contact. Therefore, the lower rotor 32 can be positioned in the axial direction by the maximum outer diameter portion 24 of the shaft 20. Thereby, the positioning of the lower rotor 32 in the axial direction becomes easy. The lower rotor upper surface 36e is the upper surface of the lower rotor main body 36.

As shown in FIGS. 1 and 3, the diameter of the fitting portion of the shaft 20 is smaller as the fitting portion is provided away from the maximum outer diameter portion 24. That is, the diameter of the upper rotor fitting portion 21 is smaller than the diameter of the upper bearing fitting portion 22. The diameter of the retaining member fitting portion 26 is smaller than the diameter of the lower rotor fitting portion 25, and the diameter of the lower bearing fitting portion 27 is smaller than the diameter of the retaining member fitting portion 26. Therefore, it is easy to mount the parts mounted on the shaft 20 from the position close to the maximum outer diameter portion 24. Parts are installed in order. Thereby, the assemblability of the motor 10 can be improved.

As shown in FIG. 2, the upper bearing support portion 23 supports the upper bearing 51 from the lower side. That is, the upper surface of the upper bearing support portion 23 is in contact with the lower surface of the upper bearing 51. Therefore, the upper bearing 51 can be stably held in the axial direction. The diameter of the upper bearing support portion 23 is larger than the diameter of the upper bearing fitting portion 22. As shown in FIG. 1, the output shaft portion 28 protrudes to the outside of the casing 11 via the output shaft hole 15a.

Next, the upper rotor 31 and the lower rotor 32 will be described in detail. FIG. 4 is a plan view showing the upper rotor 31. As shown in FIGS. 1 and 4, the upper rotor main body 34 has an upper plate-like portion (plate-like portion) 34a and an upper tubular portion (tubular portion) 34b.

The upper magnet 33 is fixed to the upper plate-like portion 34a. The upper side plate portion 34a is a plate-shaped plate portion. The upper side plate portion 34a is, for example, a disk shape extending in the radial direction. As shown in FIG. 2, the upper side plate portion 34a is fixed to the upper end of the shaft 20 by, for example, a screw.

The upper side tubular portion 34b extends in the axial direction from the upper side plate portion 34a. The upper side tubular portion 34b extends downward from the lower surface of the upper side plate portion 34a, for example. The upper rotor fitting portion 21 is fitted to the inner side of the upper tubular portion 34b. That is, the shaft 20 is fitted inside the upper tubular portion 34b.

Therefore, the axial dimension of the portion of the upper rotor 31 fitted to the shaft 20 can be increased by only the axial dimension of the upper tubular portion 34b. Thereby, it can suppress that the upper side rotor 31 is inclined and fixed with respect to the shaft 20. Therefore, the distance between the upper magnet 33 and the stator 40 in the axial direction can be easily equalized in the circumferential direction, and the application to the upper rotor 31 can be obtained substantially uniformly in the circumferential direction. Rotational torque generated by magnetic force.

Further, since it is possible to suppress the inclination of the upper rotor 31 with respect to the shaft 20, it is easy to arrange the entire upper magnet 33 close to the stator 40. Thereby, the rotational torque generated by the magnetic force applied to the upper rotor 31 can be increased. Further, the axial size of the motor 10 can be reduced.

The lower end of the upper cylindrical portion 34b overlaps the core 41 in the radial direction. That is, at least a part of the upper tubular portion 34b overlaps the iron core 41 in the radial direction. Therefore, the axial dimension of the upper tubular portion 34b can be increased to further suppress the inclination of the upper rotor 31, and the motor 10 can be prevented from increasing in size in the axial direction.

The upper rotor body 34 is provided with an upper rotor hole portion (rotor hole portion) 34c. That is, the upper rotor 31 is provided with the upper rotor hole portion 34c. The upper rotor hole portion 34c is a rotor hole portion, and the rotor hole portion is a hole through which the shaft 20 passes. The upper rotor hole portion 34c is recessed, for example, to the upper side. A part of the inner circumferential surface of the upper rotor hole portion 34c is an inner circumferential surface of the upper cylindrical portion 34b. Further, the upper rotor hole portion 34c may penetrate the upper rotor main body 34 in the axial direction or may not penetrate the upper rotor main body 34.

As shown in Fig. 1, the upper magnet 33 is fixed to the lower surface of the upper plate-like portion 34a. As shown in FIG. 4, the upper magnet 33 includes a plurality of upper magnets 33N and a plurality of upper magnets 33S.

The upper magnet 33N is magnetized to the N pole. The upper magnet 33S is magnetized to the S pole. The plurality of upper magnets 33N and the plurality of upper magnets 33S are alternately arranged in the circumferential direction. Thereby, with respect to the magnetic pole of the upper magnet 33, the N pole and the S pole are alternately arranged in the circumferential direction.

FIG. 5 is a plan view showing the lower rotor 32. As shown in Figure 1 and Figure 5 The lower rotor main body 36 has a lower plate-like portion (plate-like portion) 36a and a lower tubular portion (cylindrical portion) 36b.

The lower magnet 35 is fixed to the lower plate portion 36a. The lower side plate portion 36a is, for example, a disk shape extending in the radial direction. As shown in FIG. 2, the lower side plate-shaped part 36a is fitted in the lower side rotor fitting part 25.

The lower side tubular portion 36b extends in the axial direction from the lower side plate portion 36a. The lower side cylindrical portion 36b extends downward from the lower surface of the lower side plate portion 36a, for example. The lower rotor fitting portion 25 is fitted to the inner side of the lower tubular portion 36b. That is, the shaft 20 is fitted inside the lower tubular portion 36b.

Therefore, the axial dimension of the portion of the lower rotor 32 fitted to the shaft 20 can be increased by only the axial dimension of the lower cylindrical portion 36b. Thereby, it can suppress that the lower side rotor 32 is inclined and fixed with respect to the shaft 20. Therefore, the distance between the lower magnet 35 and the stator 40 in the axial direction can be easily equalized in the circumferential direction, and the rotational torque generated by the magnetic force applied to the lower rotor 32 can be obtained substantially uniformly in the circumferential direction.

Further, since it is possible to suppress the lower rotor 32 from being inclined with respect to the shaft 20, it is easy to arrange the lower magnet 35 as a whole as close to the stator 40. Thereby, the rotational torque generated by the magnetic force applied to the lower rotor 32 can be increased. Further, the axial size of the motor 10 can be reduced.

A lower rotor hole portion (rotor hole portion) 36c is provided in the lower rotor main body 36. That is, the lower rotor 32 is provided with the lower rotor hole portion 36c. The lower rotor hole portion 36c is a hole through which the shaft 20 passes. The lower rotor hole portion 36c penetrates the lower rotor main body 36 in the axial direction. A part of the inner circumferential surface of the lower rotor hole portion 36c is an inner circumferential surface of the lower cylindrical portion 36b.

The lower magnet 35 is fixed to the upper surface of the lower side plate portion 36a. The upper surface of the lower side plate portion 36a is the lower rotor upper surface 36e. As shown in FIG. 5, the lower magnet 35 has a plurality of lower magnets 35N and a plurality of lower magnets 35S.

The lower magnet 35N is magnetized to an N pole. The lower magnet 35S is magnetized to the S pole. The plurality of lower magnets 35N and the plurality of lower magnets 35S are alternately arranged in the circumferential direction. Thereby, with respect to the magnetic pole of the lower magnet 35, the N pole and the S pole are alternately arranged in the circumferential direction.

As shown in FIG. 1, the lower magnet 35N and the upper magnet 33S face each other in the axial direction. The lower magnet 35S and the upper magnet 33N face each other in the axial direction. Thereby, the upper magnet 33 and the lower magnet 35 face each other in the axial direction with different poles.

As shown in FIG. 4 and FIG. 5, the outline lines on both sides in the circumferential direction of the upper magnets 33N and 33S and the outline lines on the circumferential sides of the lower magnets 35N and 35S are in a plan view and a radial line passing through the center axis J. cross. In other words, the line extending in the circumferential direction on both sides of the upper magnets 33N and 33S and the line extending on both sides in the circumferential direction of the lower magnets 35N and 35S do not intersect the central axis J. That is, the upper magnets 33N and 33S and the lower magnets 35N and 35S are skewed. Therefore, the torque ripple of the motor 10 and the cogging torque can be reduced.

As shown in FIG. 4, the upper rotor 31 has an upper rotor reference position (reference position) BP1. As shown in FIG. 5, the lower rotor 32 has a lower rotor reference position (reference position) BP2. When the circumferential center of the N pole of the upper rotor 31 and the circumferential center of the S pole of the lower rotor 32 are overlapped in the axial direction, the upper rotor reference position BP1 and the lower rotor reference position BP2 are in the same circumferential position. Base position.

In addition, the circumferential center of the N pole of the upper rotor 31 is, for example, It is the circumferential center of the radially outer end of the upper magnet 33N. The circumferential center of the S pole of the lower rotor 32 is, for example, the circumferential center of the radially outer end portion of the lower magnet 35S.

As shown in FIG. 4, the upper rotor reference position BP1 is the circumferential center of the radially outer end portion of the upper magnet 33N. In other words, the upper rotor reference position BP1 is the circumferential center of the radially outer end portion of the magnetic pole of the upper magnet 33.

As shown in FIG. 5, the lower rotor reference position BP2 is the circumferential center of the radially outer end portion of the lower magnet 35S. In other words, the lower rotor reference position BP2 is the circumferential center of the radially outer end portion of the magnetic pole of the lower magnet 35.

As shown in FIG. 2, a fitting structure 39 is provided in the shaft 20, the upper rotor 31, and the lower rotor 32. The fitting structure 39 determines the relative position of the shaft 20 and the upper rotor 31 in the circumferential direction, and determines the shaft 20 and the lower side. The relative position of the rotor 32 in the circumferential direction. Therefore, the upper rotor 31 and the lower rotor 32 can be positioned with respect to the shaft 20 in the circumferential direction with high precision and ease. Thereby, it is possible to obtain the motor 10 having a configuration capable of accurately positioning the relative positions of the upper rotor 31 and the lower rotor 32 of the two rotors in the circumferential direction with high precision.

The fitting structure 39 includes an upper side fitting structure 37 and a lower side fitting structure 38. The upper fitting structure 37 is provided to the shaft 20 and the upper rotor 31. The lower side fitting structure 38 is provided to the shaft 20 and the lower side rotor 32.

The upper fitting structure 37 positions the upper rotor 31 with respect to the shaft 20 in the circumferential direction. The upper fitting structure 37 has an upper shaft side key groove portion (shaft side key groove portion) 21a, an upper rotor side key groove portion (rotor side key groove portion) 34d, and a key member 60.

The upper shaft side key groove portion 21a is provided on the outer circumferential surface of the shaft 20. More specifically, the upper shaft side key groove portion 21 a is provided on the outer circumferential surface of the upper side rotor fitting portion 21 . The upper shaft side key groove portion 21a is recessed radially inward from the outer circumferential surface of the upper rotor fitting portion 21. The upper shaft side key groove portion 21a extends in the axial direction. The upper shaft side key groove portion 21a opens upward in the axial direction toward the upper end surface of the shaft 20. As shown in FIGS. 2 and 3, the shape of the upper-axis side key groove portion 21a is, for example, a substantially rectangular parallelepiped shape.

As shown in FIG. 2, the upper rotor side key groove portion 34d is provided on the inner circumferential surface of the upper rotor hole portion 34c. The upper rotor side key groove portion 34d is recessed radially outward from the inner circumferential surface of the upper rotor hole portion 34c. The upper rotor side key groove portion 34d extends in the axial direction. The upper rotor side key groove portion 34d opens downward in the axial direction toward the lower end surface of the upper rotor main body 34. More specifically, the upper rotor side key groove portion 34d opens downward in the axial direction toward the lower end surface of the upper side cylindrical portion 34b. As shown in FIGS. 2 and 4, the upper rotor side key groove portion 34d has a substantially rectangular parallelepiped shape.

As shown in Fig. 2, the key member 60 is fitted to the upper shaft side key groove portion 21a and the upper rotor side key groove portion 34d. That is, the key member 60 is located between the upper shaft side key groove portion 21a and the upper rotor side key groove portion 34d in the radial direction. Thereby, the upper rotor 31 is positioned in the circumferential direction with respect to the shaft 20 and is fixed to the shaft 20. A key groove portion may be provided to each of the shaft 20 and the upper rotor 31 as a part of the upper fitting structure 37. Therefore, the processing of the shaft 20 and the upper rotor 31 is facilitated, and the upper fitting structure 37 can be easily manufactured. The shape of the key member 60 is, for example, a rectangular parallelepiped shape.

The lower side fitting structure 38 positions the lower side rotor 32 with respect to the shaft 20 in the circumferential direction. The lower fitting structure 38 has a lower shaft side key groove portion (shaft side key groove portion) 25a, a lower rotor side key groove portion (rotor side key groove portion) 36d, and a key member. 61.

The lower shaft side key groove portion 25a is provided on the outer circumferential surface of the shaft 20, and more specifically, the lower shaft side key groove portion 25a is provided on the outer circumferential surface of the lower side rotor fitting portion 25. The lower shaft side key groove portion 25a is recessed radially inward from the outer circumferential surface of the lower rotor fitting portion 25. The lower shaft side key groove portion 25a extends in the axial direction. The lower shaft side key groove portion 25a opens downward in the axial direction toward the lower end surface of the lower side rotor fitting portion 25. As shown in FIGS. 2 and 3, the shape of the lower-axis side key groove portion 25a is, for example, a substantially rectangular parallelepiped shape.

As shown in FIG. 2, the lower rotor side key groove portion 36d is provided on the inner circumferential surface of the lower rotor hole portion 36c. The lower rotor side key groove portion 36d is recessed radially outward from the inner circumferential surface of the lower rotor hole portion 36c. The lower rotor side key groove portion 36d extends in the axial direction. The lower rotor side key groove portion 36d penetrates the lower rotor main body 36 in the axial direction. As shown in FIGS. 2 and 5, the shape of the lower rotor side key groove portion 36d is a substantially rectangular parallelepiped shape.

As shown in Fig. 2, the key member 61 is fitted to the lower shaft side key groove portion 25a and the lower rotor side key groove portion 36d. That is, the key member 61 is located between the lower-axis side key groove portion 25a and the lower rotor-side key groove portion 36d in the radial direction. Thereby, the lower rotor 32 is positioned in the circumferential direction with respect to the shaft 20 and is fixed to the shaft 20. A key groove portion may be provided to each of the shaft 20 and the lower rotor 32 as a part of the lower fitting structure 38. Therefore, the processing of the shaft 20 and the lower rotor 32 becomes easy, and the lower fitting structure 38 can be easily manufactured. The shape of the key member 61 is, for example, a rectangular parallelepiped shape.

As shown in FIG. 4, the upper circumferential center P1 which is the circumferential center of the upper rotor side key groove portion 34d is provided at the same position as the upper rotor reference position BP1 in the circumferential direction. That is, the upper circumferential center P1 is worn when viewed in the axial direction. Passing over the first radial line SL1 of the upper rotor reference position BP1.

The upper rotor reference position BP1 is the circumferential center of the radially outer end portion of the upper magnet 33N. Therefore, the circumferential center of the upper rotor side key groove portion 34d can be positioned with respect to the circumferential center of the upper magnet 33N. Thereby, it is easy to determine the position at which the upper rotor side key groove portion 34d is provided.

As shown in FIG. 5, the lower circumferential center P2 which is the circumferential center of the lower rotor side key groove portion 36d is provided at a position different from the lower rotor reference position BP2 in the circumferential direction. That is, the lower circumferential center P2 is located on the third radial line SL3 different from the second radial line SL2 passing through the lower rotor reference position BP2 when viewed in the axial direction.

The lower rotor reference position BP2 is the circumferential center of the radially outer end portion of the lower magnet 35S. Therefore, the circumferential center of the lower rotor side key groove portion 36d can be positioned with respect to the circumferential center of the lower magnet 35S. Thereby, it is easy to determine the position at which the lower rotor side key groove portion 36d is provided.

As shown in FIG. 3, the upper-axis side key groove portion 21a and the lower-axis side key groove portion 25a are disposed at the same position in the circumferential direction. Thereby, the upper rotor 31 and the lower rotor 32 are fixed to the shaft 20 in a state where the circumferential center of the upper magnet 33N and the circumferential center of the lower magnet 35S are shifted in the circumferential direction.

Therefore, the magnetic field generated between the upper magnet 33N and the lower magnet 35S that face each other in the axial direction and between the upper magnet 33S and the lower magnet 35N that face each other in the axial direction are inclined with respect to the axial direction. That is, the magnetic field generated between the upper rotor 31 and the lower rotor 32 is skewed. Thus, according to the present embodiment, the torque ripple and the cogging torque of the motor 10 can be reduced.

In the following description, there is a case where the pair of rotors on the upper side will be present. The skewing of the magnetic field generated between the 31 and the lower rotor 32 is only expressed as skewing the upper rotor 31 and the lower rotor 32.

Further, in the present specification, the so-called two objects are disposed at the same position in the circumferential direction including the two objects overlapping each other in the radial direction when viewed in the axial direction. Further, in the present specification, the so-called two objects are disposed at different positions in the circumferential direction including that two objects do not overlap each other in the radial direction when viewed in the axial direction.

The circumferential center of the upper magnet 33N and the circumferential center of the lower magnet 35S are shifted only in the circumferential direction by the skew angle θ shown in FIG. 5 . The skew angle θ is an angle between the second radial line SL2 and the circumferential direction of the third radial line SL3. In a state where the upper rotor 31 and the lower rotor 32 are fixed to the shaft 20, the first radial line SL1 and the third radial line SL3 overlap each other when viewed in the axial direction. That is, the skew angle θ is also an angle between the first radial line SL1 and the circumferential direction of the second radial line SL2. The skew angle θ is, for example, 3 degrees or more and 6 degrees or less.

The torque ripple caused by the skew of the upper rotor 31 and the lower rotor 32 and the effect of reducing the cogging torque are greatly different depending on the magnitude of the skew angle θ. Further, when the skew angle θ is deviated from the design value, the magnetic flux generated between the upper rotor 31 and the lower rotor 32 becomes uneven in the circumferential direction, and is generated in the upper rotor 31 and the lower rotor 32. Vibration and noise increase.

On the other hand, in the preferred embodiment, the relative positions of the upper rotor 31 and the lower rotor 32 in the circumferential direction can be accurately positioned by the upper fitting structure 37 and the lower fitting structure 38. Therefore, the accuracy of the skew angle θ can be improved. Thus, the preferred embodiment is effective in reducing torque ripple and teeth The groove torque and the vibration and noise generated in the upper rotor 31 and the lower rotor 32 can be suppressed from increasing.

Further, in the preferred embodiment, the following structure can also be employed. In the following description, the same configurations as those described above are omitted by appropriately designating the same reference numerals and the like.

The lower circumferential center P2 may be provided at the same position as the lower rotor reference position BP2 in the circumferential direction. That is, the lower circumferential center P2 may be located on the second radial line SL2 when viewed in the axial direction. According to this configuration, the skew angle θ becomes 0 degrees. That is, the upper rotor 31 and the lower rotor 32 are not skewed. According to this configuration, the rotational torque of the motor 10 can be increased. Further, since the accuracy of the skew angle θ can be improved by the upper fitting structure 37 and the lower fitting structure 38, it is easy to obtain a desired rotational torque.

Further, for example, as shown in the configuration of FIG. 6, the upper rotor 31 and the lower rotor 32 can be skewed by shifting the upper shaft side key groove portion 21a and the lower shaft side key groove portion 25a in the circumferential direction. Fig. 6 is a side view (YZ plan view) showing the shaft 120 as another example of the preferred embodiment. As shown in FIG. 6, the shaft 120 has a lower side rotor fitting portion (fitting portion) 125.

The lower rotor fitting portion 125 is a fitting portion to which the lower rotor 32 is fitted. A lower shaft side key groove portion (shaft side key groove portion) 125a is provided on the outer circumferential surface of the lower rotor fitting portion 125. The upper shaft side key groove portion 21a and the lower shaft side key groove portion 125a are provided at positions different from each other in the circumferential direction. The other structure of the shaft 120 is the same as that of the shaft 20 shown in Figs.

In this configuration, the upper circumferential center P1 is provided at the same position as the upper rotor reference position BP1 in the circumferential direction. The lower circumferential center P2 is in the circumferential direction The upper portion is disposed at the same position as the lower rotor reference position BP2. Thereby, the upper rotor 31 and the lower rotor 32 can be skewed. In this configuration, the skew angle is a shift angle of the circumferential center of the upper-axis side key groove portion 21a and the circumferential center of the lower-axis side key groove portion 125a in the circumferential direction.

According to this configuration, the upper rotor 31 and the lower rotor 32 are skewed, and the circumferential position of the upper rotor side key groove portion 34d with respect to the magnetic pole can be made the same as the circumferential position of the lower rotor side key groove portion 36d with respect to the magnetic pole. . Thereby, the upper rotor side key groove portion 34d and the lower rotor side key groove portion 36d can be positioned in the same manner with respect to the magnet, which is easy.

Further, at least one of the upper rotor 31 and the lower rotor 32 may have a tubular portion. In other words, only one of the upper tubular portion 34b and the lower tubular portion 36b may be provided.

In addition, the one surface in the axial direction of the largest outer diameter portion 24 can be in contact with the surface of the maximum outer diameter portion 24 side (+Z side) of either one of the upper rotor 31 and the lower rotor 32. In other words, the upper surface of the maximum outer diameter portion 24 may be in contact with the lower surface of the upper rotor 31.

Further, a plurality of upper rotor side key groove portions 34d and lower rotor side key groove portions 36d may be provided. Further, in the present embodiment, a plurality of the upper shaft side key groove portion 21a and the lower shaft side key groove portion 25a may be provided. According to this configuration, for example, by changing the key groove portion in which the key members 60 and 61 are fitted, it is possible to change the shift angle of the upper side rotor 31 and the lower side rotor 32 in the circumferential direction, that is, to change the skew angle θ.

When the circumferential center of the upper magnet 33N overlaps the circumferential center of the lower magnet 35S in the axial direction, the upper rotor reference position BP1 changes. The upper rotor reference position BP1 may be an arbitrary position in the same position as the lower rotor reference position BP2 in the circumferential direction. The same is true for the lower rotor reference position BP2. Therefore, the rotor reference position is not limited to the case of the circumferential center of the radially outer end portion of the magnetic pole.

Further, the upper magnet 33 and the lower magnet 35 may be an integral member. In this case, for example, the upper magnet 33 and the lower magnet 35 have an annular shape, and the N pole and the S pole are alternately magnetized in the circumferential direction.

It is preferable that the second embodiment differs from the first embodiment in that the fitting structure has a convex portion and a concave portion instead of the key groove portion and the key member. In the same configuration as the first embodiment, the description will be omitted by appropriately arranging the same reference numerals and the like.

FIG. 7 is a cross-sectional view showing the lower rotor 232. Fig. 7 is a view as seen from the upper side (+Z side) toward the lower side (-Z side). As shown in FIG. 7, the lower rotor 232 has a lower rotor main body 236 and a lower side magnet 35. The lower rotor main body 236 has a lower side plate portion 36a, a lower side cylindrical portion 36b, and a convex portion 236d.

The convex portion 236d is provided on the inner circumferential surface of the lower rotor hole portion 36c. The convex portion 236d is convex radially inward from the inner circumferential surface of the lower rotor hole portion 36c. That is, the convex portion 236d is convex in the radial direction. Therefore, the convex portion 236d is more easily produced than in the case where the convex portion 236d is provided on the outer circumferential surface of the shaft 20.

The lower side rotor 232 is provided with a lower side fitting structure 238 that positions the lower side rotor 232 with respect to the shaft 20 in the circumferential direction. The lower side fitting structure 238 has a convex portion 236d and a lower shaft side key groove portion 25a. The lower shaft side key groove portion 25a is a concave portion that is recessed in the radial direction. The convex portion 236d is fitted to the lower shaft side key groove portion 25a.

Since the lower fitting structure 238 is constituted by the convex portion 236d and the lower shaft side key groove portion 25a, it is not necessary to provide the key member 61. Thereby, the number of parts of the motor can be reduced. Therefore, the assembly man-hour of the motor and the manufacturing cost of the motor can be reduced.

The convex portion center P3 which is the circumferential center of the convex portion 236d is provided at the same position as the lower rotor reference position BP2 in the circumferential direction. In other words, the circumferential center of the portion of the lower fitting structure 238 provided on the lower rotor 232 is provided at the same position as the lower rotor reference position BP2 in the circumferential direction. The shape of the convex portion 236d is, for example, a rectangular parallelepiped shape.

Although the illustration is omitted, the upper side fitting structure has a convex portion and a concave portion. The convex portion of the upper fitting structure is provided, for example, on the inner circumferential surface of the upper rotor hole portion 34c. The convex portion of the upper fitting structure is convex outward from the inner circumferential surface of the upper rotor hole portion 34c. Therefore, it is easier to produce a convex portion than when the convex portion is provided on the outer circumferential surface of the shaft 20. The concave portion of the upper fitting structure is, for example, the upper shaft side key groove portion 21a shown in Fig. 2 .

The portion of the upper side fitting structure provided on the upper rotor, that is, the circumferential center of the convex portion is provided at the same position as the upper rotor reference position BP1 in the circumferential direction. Further, as described in the first embodiment, the upper-axis side key groove portion 21a and the lower-axis side key groove portion 25a are provided at the same position in the circumferential direction. That is, the concave portion of the upper side fitting structure and the concave portion of the lower side fitting structure 238 are disposed at the same position in the circumferential direction. Thereby, no skew is applied to the two rotors. Therefore, the rotational torque of the motor can be increased.

Further, in the second preferred embodiment, the following configuration can be employed.

In the present embodiment, the concave portion may be provided on one of the inner circumferential surface of the lower rotor hole portion 36c and the outer circumferential surface of the shaft 20, and the convex portion 236d may be provided on the inner circumferential surface of the lower rotor hole portion 36c and the outer circumferential surface of the shaft 20. The other party. That is, the convex portion 236d may be provided on the outer circumferential surface of the shaft 20. In this case, for example, the lower rotor side key groove portion 36d shown in FIG. 5 is provided as a concave portion on the inner circumferential surface of the lower rotor hole portion 36c. The convex portion 236d is fitted to the lower rotor side key groove portion 36d. The same is true for the upper side fitting structure.

Further, the circumferential center of the portion of the lower fitting structure 238 provided on the lower rotor 232 may be provided at a position different from the lower rotor reference position BP2 of the lower rotor 232 in the circumferential direction. According to this configuration, since the two rotors are skewed, the torque ripple of the motor and the cogging torque can be reduced.

Further, the shaft 20 may have the same structure as the shaft 120 shown in FIG. 6. That is, the recessed portion of the upper side fitting structure and the recessed portion of the lower side fitting structure 238 may be disposed at positions different from each other in the circumferential direction. In this case, the recessed portion of the upper side fitting structure is the upper shaft side key groove portion 21a shown in Fig. 6 . The concave portion of the lower fitting structure 238 is the lower shaft side key groove portion 125a shown in Fig. 6 . According to this configuration, since the two rotors are skewed, the torque ripple of the motor and the cogging torque can be reduced.

Further, in the second preferred embodiment, one of the upper fitting structure and the lower fitting structure 238 may be a fitting structure using the key groove portion and the key member shown in FIG. 2 and the like.

Further, the respective configurations of the first embodiment and the second embodiment described above can be combined as appropriate within a range that does not contradict each other.

10‧‧‧ motor

20‧‧‧Axis

21‧‧‧Upper rotor fitting part (fitting part)

21a‧‧‧Upper shaft side keyway section (shaft side keyway section)

22‧‧‧Upper bearing fitting part (fitting part)

23‧‧‧Upper bearing support

24‧‧‧Maximum OD

24a‧‧‧Maximum outer diameter lower surface

25‧‧‧Bottom rotor fitting part (fitting part)

25a‧‧‧Bottom side keyway section (shaft side keyway section)

26‧‧‧Removal-proof part fitting part (fitting part)

31‧‧‧Upper rotor

32‧‧‧lower rotor

33, 33N, 33S‧‧‧ upper magnet

34‧‧‧Upper rotor body

34a‧‧‧Upper plate (board)

34b‧‧‧Upper tubular part (cylindrical part)

34c‧‧‧Upper rotor hole (rotor hole)

34d‧‧‧Upper rotor side keyway (rotor side keyway)

35, 35N, 35S‧‧‧ lower magnet

36‧‧‧Bottom rotor body

36a‧‧‧Bottom plate (plate)

36b‧‧‧Bottom cylindrical part (cylindrical part)

36c‧‧‧Bottom rotor hole (rotor hole)

36d‧‧‧ Lower rotor side keyway (rotor side keyway)

36e‧‧‧ Upper rotor upper surface

37‧‧‧Upside chimeric structure

38‧‧‧Bottom fitting structure

39‧‧‧Chimeric structure

40‧‧‧ Stator

41‧‧‧ iron core

42‧‧‧ coil

42a‧‧‧Coil lead wire

43‧‧‧Insulation

44‧‧‧Upper bearing cage

51‧‧‧Upper bearing

60, 61‧‧‧ key components

80‧‧‧Removal parts

J‧‧‧ central axis

Claims (15)

A motor having a shaft centered on a central axis extending in an up-and-down direction, an upper rotor and a lower rotor mounted to the shaft at a predetermined interval in the axial direction, and a stator disposed in the shaft Between the upper rotor and the lower rotor; and a bearing supporting the shaft, the upper rotor and the lower rotor having magnets, the magnets being axially opposed to the stator, with respect to the magnets a magnetic pole in which the N pole and the S pole are alternately arranged in the circumferential direction, and the shaft, the upper side rotor and the lower side rotor are provided with a fitting structure, the fitting structure determining that the shaft and the upper rotor are The relative position in the circumferential direction, and determines the relative position of the shaft and the lower rotor in the circumferential direction. The motor according to claim 1, wherein the upper side rotor and the lower side rotor have a rotor hole portion, the rotor hole portion being a hole through which the shaft passes, and the fitting structure has an upper side embedded a structure that positions the upper rotor in a circumferential direction with respect to the shaft; and a lower fitting structure that circumferentially positions the lower rotor relative to the shaft, The upper side fitting structure and the lower side fitting structure have a shaft side key groove portion provided on an outer circumferential surface of the shaft and recessed radially inward; and a rotor side key groove portion provided in the rotor hole The inner peripheral surface of the portion is recessed outward in the radial direction; and a key member is fitted to the shaft side key groove portion and the rotor side key groove portion. The motor according to claim 2, wherein the shaft side key groove portion of the upper side fitting structure and the shaft side key groove portion of the lower side fitting structure are located at the same position in the circumferential direction, When the circumferential center of the N pole of the upper rotor and the circumferential center of the S pole of the lower rotor overlap in the axial direction, the upper rotor and the lower rotor have the same circumferential position a reference position at which a circumferential center of the rotor-side key groove portion of the upper rotor is located at the same position as the reference position of the upper rotor in the circumferential direction, and the rotor-side key groove portion of the lower rotor The circumferential center is located at the same position as the reference position of the lower rotor in the circumferential direction. The motor according to claim 2, wherein the shaft side key groove portion of the upper side fitting structure and the shaft side key groove portion of the lower side fitting structure are circumferentially identical to each other a position in which the upper side rotor and the lower side rotor have each other when axially overlapping a circumferential center of the N pole of the upper side rotor with a circumferential center of the S pole of the lower side rotor a reference position in which the circumferential direction is the same, a circumferential center of the rotor-side key groove portion of the upper rotor is circumferentially located at the same position as the reference position of the upper rotor, and the rotor of the lower rotor The circumferential center of the side key groove portion is located at a position different from the reference position of the lower rotor in the circumferential direction. The motor according to claim 2, wherein the shaft side key groove portion of the upper side fitting structure and the shaft side key groove portion of the lower side fitting structure are located at mutually different positions in the circumferential direction, When the circumferential center of the N pole of the upper rotor and the circumferential center of the S pole of the lower rotor overlap in the axial direction, the upper rotor and the lower rotor have the same circumferential position a reference position at which a circumferential center of the rotor-side key groove portion of the upper rotor is located at the same position as the reference position of the upper rotor in the circumferential direction, and the rotor-side key groove portion of the lower rotor The circumferential center is located in the circumferential direction at the same position as the reference position of the lower rotor Set. The motor according to claim 1, wherein the upper side rotor and the lower side rotor have a rotor hole portion, the rotor hole portion being a hole through which the shaft passes, and the fitting structure has an upper side embedded a structure that positions the upper rotor in a circumferential direction with respect to the shaft; and a lower fitting structure that circumferentially positions the lower rotor with respect to the shaft, the upper side fitting The structure and the lower side fitting structure have a recess that is recessed in the radial direction, and a convex portion that is fitted to the recess and that is convex in the radial direction, the recess being located inside the rotor hole One of the circumferential surface and the outer circumferential surface of the shaft, the convex portion being located on the other of the inner circumferential surface of the rotor hole portion and the outer circumferential surface of the shaft. The motor according to claim 6, wherein the concave portion is located on an outer circumferential surface of the shaft, and the convex portion is located on an inner circumferential surface of the rotor hole portion. The motor according to claim 6 or 7, wherein the recess of the upper side fitting structure and the recess of the lower side fitting structure are circumferentially located at the same position with each other, and the upper rotor is When the circumferential center of the N pole overlaps the circumferential center of the S pole of the lower rotor in the axial direction, the upper side The rotor and the lower side rotor have reference positions that are identical to each other in a circumferential position, and a circumferential center of a portion of the upper side fitting structure provided at the upper side rotor is circumferentially located at the reference position with the upper side rotor In the same position, the circumferential center of the portion of the lower side fitting structure provided on the lower side rotor is located at the same position as the reference position of the lower side rotor in the circumferential direction. The motor according to claim 6 or 7, wherein the recess of the upper side fitting structure and the recess of the lower side fitting structure are circumferentially located at the same position with each other, and the upper rotor is When the circumferential center of the N pole overlaps the circumferential center of the S pole of the lower rotor in the axial direction, the lower rotor of the upper rotor has the same reference position as the circumferential position of each other. The circumferential center of the portion of the upper side fitting structure provided on the upper side rotor is located at the same position as the reference position of the upper side rotor in the circumferential direction, and the lower side fitting structure is disposed on the lower side The circumferential center of the portion of the rotor is located circumferentially at a position different from the reference position of the lower rotor. The motor according to claim 6 or 7, wherein the recess of the upper side fitting structure and the recess of the lower side fitting structure are located at mutually different positions in the circumferential direction, and the upper rotor is The circumferential center of the N pole and the lower When the circumferential center of the S pole of the side rotor overlaps in the axial direction, the upper side rotor and the lower side rotor have the same reference position in circumferential position, and the upper side fitting structure is disposed on the upper side rotor The circumferential center of the portion is located at the same position as the reference position of the upper rotor in the circumferential direction, and the circumferential center of the portion of the lower side fitting structure provided at the lower rotor is circumferentially located The reference position of the lower rotor is the same position. The motor according to any one of claims 3 to 5, wherein the reference position is a circumferential center of an end portion of a radially outer side of the magnetic pole. The motor according to any one of claims 1 to 7, wherein the upper side rotor and the lower side rotor have a plate-like plate-shaped portion, and the magnet is fixed to the plate-shaped portion, At least one of the upper rotor and the lower rotor has a tubular tubular portion extending in the axial direction from the plate-like portion, and the shaft is fitted inside the tubular portion . The motor of claim 12, wherein the stator has a core and a coil that excites the core, at least a portion of the tubular portion overlapping the core in a radial direction. The motor of any one of claims 1 to 7, wherein the shaft is a stepped shaft having a plurality of different diameters a portion, wherein a maximum outer diameter portion of the shaft having a largest diameter is axially located between the upper side rotor and the lower side rotor, and an axial side surface of the maximum outer diameter portion and the upper side rotor and the portion The surface on the side of the largest outer diameter portion of any one of the lower rotors is in contact with each other. The motor according to claim 14, wherein the shaft has a plurality of fitting portions, and the fitting portion is fitted with other parts, and the diameter of the fitting portion is set to be farther away from the fitting portion. The smaller the position of the largest outer diameter portion is.