Motor, fan, and air conditioner
A motor includes a rotor having a shaft, a rotor core, and a permanent magnet, and a stator surrounding the rotor. The permanent magnet forms a magnet magnetic pole, a part of the rotor core forms a virtual magnetic pole. The motor includes first and second bearings support the shaft, and further includes first and second bearing support portions. Of the first and second bearings, the first bearing is located on the load side. A distance D 1 from the center axis to the inner circumferential surface of the first bearing support portion, a distance D 2 from the center axis to the inner circumferential surface of the second bearing support portion, a distance d 1 from the center axis to the outer circumferential surface of the first bearing, and a distance d 2 from the center axis to the outer circumferential surface of the second bearing satisfy D 1 −d 1 <D 2 −d 2.
1. A motor comprising:
a rotor having a shaft, a rotor core surrounding the shaft from outside in a radial direction about a center axis of the shaft, and a permanent magnet attached to the rotor core, the permanent magnet forming a magnet magnetic pole, a part of the rotor core forming a virtual magnetic pole;
a stator surrounding the rotor from outside in the radial direction;
a first bearing and a second bearing supporting the shaft; and
a first bearing support portion having an inner circumferential surface facing an outer circumferential surface of the first bearing; and
a second bearing support portion having an inner circumferential surface facing an outer circumferential surface of the second bearing,
wherein one side of the shaft in a direction of the center axis is defined as a load side to which a load is applied;
wherein, of the first bearing and the second bearing, the first bearing is located on the load side;
wherein a distance D 1 from the center axis to the inner circumferential surface of the first bearing support portion, a distance D 2 from the center axis to the inner circumferential surface of the second bearing support portion, a distance d 1 from the center axis to the outer circumferential surface of the first bearing, and a distance d 2 from the center axis to the outer circumferential surface of the second bearing satisfy D 1 −d 1 <D 2 −d 2 , and
wherein D 1 <D 2 and d 1 =d 2 are both satisfied, or d 1 >d 2 is satisfied.
2. The motor according to claim 1 , wherein D 1 =D 2 is further satisfied.
3. The motor according to claim 1 , wherein the first bearing support portion is composed of a metal, and
wherein the second bearing support portion is composed of a resin.
4. The motor according to claim 1 , wherein the first bearing support portion is composed of a metal, and
wherein the second bearing support portion is composed of a metal.
5. The motor according to claim 4 , further comprising a mold resin portion holding the first bearing support portion and the second bearing support portion.
6. The motor according to claim 1 , wherein the first bearing and the second bearing have a same inner diameter.
7. The motor according to claim 1 , further comprising an insulator provided between the shaft and at least one of the first bearing and the second bearing.
8. The motor according to claim 1 , wherein the rotor has a resin part between the rotor core and the shaft.
9. The motor according to claim 1 , wherein at least one of the first bearing and the second bearing has a rolling element composed of a ceramic.
10. The motor according to claim 9 , wherein the first bearing has a rolling element composed of a ceramic.
11. The motor according to claim 9 , wherein each of the first bearing and the second bearing has a rolling element composed of a ceramic.
12. A fan comprising:
the motor according to claim 1 ; and
an impeller rotated by the motor.
13. An air conditioner comprising:
an outdoor unit; and
an indoor unit connected to the outdoor unit via a refrigerant pipe,
wherein at least one of the outdoor unit and the indoor unit has the fan according to claim 12 .