Induction motor rotor core having shaped slots

• US 8,466,597 B2
• Filed: 05/19/2008
• Issued: 06/18/2013
• Est. Priority Date: 12/27/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yabe, Koji, Yoshino, Hayato, Baba, Kazuhiko, Oikawa, Tomoaki, Tsutsumi, Takahiro
• Primary Examiner(s): Leung, Quyen
• Assistant Examiner(s): GONZALEZ QUINONES, JOSE A
• Application Number:
  US12/744,622
• Publication Number:
  US 20100253174A1
• Time in Patent Office: 1,856 Days
• Field of Search: 310/211, 310/212, 310/156.78, 103/216.069, 103/216.071
• US Class Current: 310/216.069
• CPC Class Codes: H02K 17/18 having double-cage or multiple-cage rotors
• CPC Class Codes: H02K 17/20 having deep-bar rotors

Abstract

To provide an indication motor rotor capable of improving motor performance by concentrating portions under magnetic saturation conditions of rotor teeth. The rotor 1 of an induction motor of this invention may include slots 3 formed approximately in the shape of a T. The slots 3 may be formed so that top slots 3a are arranged on an outer peripheral portion of a rotor core 1a, and bottom slots 3b are arranged on an inner side of the top slots 3a. The width in the circumferential direction of the top slot 3a is wider than the width in the circumferential direction of the bottom slot 3b, and the width in the circumferential direction of a rotor tooth 4 between adjacent top slots 3a is narrower than the width in the circumferential direction of the rotor tooth 4 between adjacent bottom slots 3b.

Claims

1. An induction motor rotor comprising:

a rotor core with slots formed therein, and

a squirrel-cage secondary conductor including a nonmagnetic and conductive material filled in each of the slots of the rotor core,

wherein each of the slots includes a top slot arranged at an outer peripheral portion of the rotor core and a bottom slot arranged on an inner side of the top slot,

wherein each of the slots is formed so that a width in the circumferential direction of the top slot is wider than a width in the circumferential direction of the bottom slot,

wherein each of the slots is formed so that a width in the circumferential direction of a rotor tooth between adjacent top slots is narrower than a width in the circumferential direction of the rotor tooth between adjacent bottom slots,

wherein each of the slots is formed to include a leakage slot between the top slot and the bottom slot,

wherein each of the slots is formed so that a width in the circumferential direction of the rotor tooth between adjacent leakage slots is wider than the width in the circumferential direction of the rotor tooth between the adjacent top slots and wider than the width in the circumferential direction of the adjacent bottom slots,

wherein the rotor core is formed to layer electromagnetic steel sheets, and

wherein a width in the radial direction of the leakage slot is substantially equal to the thickness of an electromagnetic steel sheet.

2. The induction motor rotor according to claim 1, wherein A is defined as a width in the radial direction of the top slot, B is defined as a width in the radial direction of the bottom slot, and A<

0.5B.

3. The induction motor rotor according to claim 1, wherein A is defined as a width in the radial direction of the top slot, C is defined as the width in the circumferential direction of the top slot, and A<

0.5C.

4. The induction motor rotor according to claim 1 further comprising:

a bridge between the top slot and the outer edge of the rotor core;

wherein a width in the radial direction of the bridge is approximately fixed.

5. The induction motor rotor according to claim 1,

wherein the width in the circumferential direction of the top slot is wider than a width in the circumferential direction of an opening formed on an inner peripheral portion of a slot of a stator.

6. The induction motor rotor according to claim 1, wherein the slot of the rotor core includes an opening that opens to outside at the outer edge of the rotor core.

7. An induction motor comprising the induction motor rotor according to claim 1.

8. A compressor comprising the induction motor according to claim 7.

9. A fan comprising the induction motor according to claim 7.

10. An air conditioner comprising the compressor according to claim 6.