Electric motor and electric equipment with same
View Patent ↗A motor includes a stator integrally molded together with a stator member, which includes a stator iron-core wound with a winding, by insulating resin, a rotor mounted on a shaft as a center and confronting the stator, two bearings supporting the shaft rotatably, brackets fixing the bearings, and a drive circuit board including a drive circuit which supplies an electric current to the winding and drives the rotor. Either one of the two bearings includes an outer ring and an inner ring both of which are electrically insulated from each other.
1. A motor comprising:
a stator including a stator iron-core and a winding wound thereon integrally molded together by insulating resin;
a rotor mounted around a shaft in a manner to face the stator;
first and second bearings supporting the shaft rotatably, the first and second bearings being spaced apart from each other along the shaft and located, respectively, on an output shaft side and a counter output shaft side of the motor, wherein the first bearing includes an electrically insulating material, not included in the second bearing, that makes an electrical resistance through the first bearing higher than an electrical resistance through the second bearing;
a bracket provided on one of the output shaft and counter output shaft sides and fixing one of the first and second bearings; and
a drive circuit that supplies an electric current to the winding and drives the rotor.
2. The motor of claim 1 , wherein each of the first and second bearings includes an outer ring, an inner ring and bearing balls sandwiched between the outer and inner rings, and the first bearing uses the electrically insulating material for at least one of the outer ring, the inner ring, and the bearing balls.
3. The motor of claim 2 , wherein the electrically insulating material is ceramic material.
4. The motor of claim 1 , wherein the bracket is provided on one of the output shaft and counter output shaft sides and fixing one of the first and second bearings, and the other of the first and second bearings is fixed to the insulating resin.
5. The motor of claim 4 , further comprising a second bracket provided on the other of the output shaft and counter output shaft sides and fixing the other of the first and second bearings, wherein the bracket and the second bracket differ in size from each other.
6. The motor of claim 5 , wherein the bracket and the second bracket are made of metal.
7. An electric apparatus including the motor as defined in any one of claims 1 - 5 .
8. The motor of claim 1 , wherein the first bearing is located on the output shaft side, and the second bearing is located on the counter output shaft side.
9. The motor of claim 1 , wherein the bracket is provided on the counter output shaft side, and no bracket is provided on the output shaft side.