ROTOR WITH END RING AND ELECTRIC MOTOR

• US 20150244234A1
• Filed: 02/17/2015
• Published: 08/27/2015
• Est. Priority Date: 02/25/2014
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Katsuki, Kyohei
• Granted Patent: US 9,825,501 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02K 17/165 characterised by the squirrel-cage or other short-circuited windings
• CPC Class Codes: H02K 2205/12 Machines characterised by means for reducing windage losses or windage noise
• CPC Class Codes: H02K 3/46 Fastening of windings on the stator or rotor structure

Abstract

An electric motor for high speed operation use and a rotor which enables use of common parts with electric motors for low speed operation use and which thereby enables reduction of the manufacturing costs. The rotor is provided with a shaft, a rotor core which is fastened to the shaft at the outside in the radial direction and has a first end face at one end in the axial direction and a second end face at the other end in the axial direction, a plurality of conductors which are arranged at the rotor core, and a pair of end rings which are respectively arranged adjoining the first end face and the second end face and which short-circuit the plurality of conductors with each other. The shaft has an outer circumference, while the end rings have outer circumferences which are arranged concentrically with respect to the outer circumference of the shaft.

Claims

1. A rotor of an electric motor, comprising:

a shaft;

a rotor core fixed radially outside of the shaft and having a first end face at one end in the axial direction and a second end face at the other end in the axial direction;

a plurality of conductors arranged at the rotor core, each of the plurality of conductors extending from the first end face to the second end face; and

a pair of end rings, one of which is arranged adjacent to the first end face, and the other of which is arranged adjacent to the second end face, the end rings short-circuiting the plurality of conductors with each other, wherein

the shaft has an outer circumference centered about an axis of rotation,

the end ring has an outer circumference arranged concentrically with respect to the outer circumference of the shaft.

2. The rotor according to claim 1, further comprising a reinforcing member including:

an inner ring part fitted over the outer circumference of the shaft; and

an outer ring par connected to the inner ring part and fitted over the outer circumference of the end ring.

3. The rotor according to claim 2, wherein the inner ring part is housed in a space defined between the outer circumference of the shaft and an inner circumference of the end ring opposite to the outer circumference of the end ring.

4. The rotor according to claim 2, wherein

the inner ring part has a first inner circumference contacting the outer circumference of the shaft,

the outer ring part has a second inner circumference contacting the outer circumference of the end ring,

the first inner circumference and the second inner circumference are concentric with each other.

5. The rotor according to claim 2, wherein

the reinforcing member further includes a ring-shaped connecting part radially extending from the inner ring part to the outer ring part,

the end ring is housed in a space defined by the inner ring part, the outer ring part, and the connecting part.

6. The rotor according to claim 2, wherein the inner ring part includes a plurality of weights arranged in the circumferential direction.

7. The rotor according to claim 6, wherein each of the plurality of weights is inserted into a tap hole formed in the inner ring part.

8. The rotor according to claim 2, wherein the reinforcing member is made from a nonmagnetic material having a higher rigidity than aluminum.

9. The rotor according to claim 2, wherein the reinforcing member is fastened to the shaft by shrink fitting or screwing.

10. An electric motor comprising a rotor according to claim 1.