Interior permanent magnet motor

Patent metadata

Field	Value
Publication number	US-9762096-B2
Application number	US-201314763866-A
Country	US
Kind code	B2
Filing date	Feb 20, 2013
Priority date	Feb 20, 2013
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

An interior permanent magnet motor includes: a rotor; a stator; and a plurality of permanent magnets respectively inserted into a plurality of magnet insertion holes formed in a rotor core, the rotor core being formed by laminating a plurality of magnetic steel sheets, the magnetic steel sheets including first magnetic steel sheets each not having a magnet stopper in the magnet insertion hole, and second magnetic steel sheets each having magnet stoppers at both end portions of the magnet insertion hole, the rotor core including a laminate of the magnetic steel sheets in a lamination mode in which, when H n represents a distance between an upper end surface of the second magnetic steel sheet and an upper end surface of the n-th second magnetic steel sheet, a progression of differences of H n is a geometric progression.

First claim

The invention claimed is:

1. An interior permanent magnet motor, comprising:
a rotor;
a stator installed so as to be opposed to the rotor with an air gap; and
a plurality of permanent magnets respectively inserted into a plurality of magnet insertion holes formed in a rotor core of the rotor,
the rotor core being formed by laminating a plurality of magnetic steel sheets,
the plurality of magnetic steel sheets comprising a plurality of first magnetic steel sheets each not having a magnet stopper in the magnet insertion hole, and a plurality of second magnetic steel sheets each having magnet stoppers at both end portions of the magnet insertion hole,
the rotor core comprising a laminate of the magnetic steel sheets in a lamination mode in which, when H n represents a distance between an upper end surface of the second magnetic steel sheet that comes first when only the second magnetic steel sheets are sequentially counted in a lamination direction from an upper side of the rotor core and an upper end surface of the n-th second magnetic steel sheet, a progression of differences of H n is a geometric progression, wherein
a chamfered portion is formed at a lower corner of the permanent magnet,
at least the magnet insertion hole of the second magnetic steel sheet is formed by punching, and a shear droop-shaped portion is formed on an upper side of the magnet stopper, and
when a 1 represents a width of the chamfered portion in a circumferential direction, a 2 represents a width of the shear droop-shaped portion in the circumferential direction, g represents a dimensional difference in the circumferential direction between the permanent magnet and the magnet insertion hole, and t represents a thickness of each of the magnetic steel sheets, a 1 , a 2 , H n , g, and t are set so as to satisfy the following expression:
H n+1 ≦{( a 1 +a 2 )/ g+ 1}( H n +t ) ( n= 1,2, . . . ).

2. An interior permanent magnet motor according to claim 1 , wherein a chamfered portion is formed at a lower corner of the permanent magnet.

3. An interior permanent magnet motor according to claim 1 , wherein at least the magnet insertion hole of the second magnetic steel sheet is formed by punching, and a shear droop-shaped portion is formed on an upper side of the magnet stopper.

4. An interior permanent magnet motor according to claim 1 , wherein the magnetic steel sheet arranged at a lower end surface of the rotor core is the second magnetic steel sheet.

Assignees

• Oketani Naohiro
• Nigo Masahiro
• Baba Kazuhiko
• Yabe Koji
• Mitsubishi Electric Corp

Inventors

• Oketani Naohiro
• Nigo Masahiro
• Baba Kazuhiko
• Yabe Koji

Classifications

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title

• H02K1/276 Primary

  Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] · CPC title

• H02K1/2706 Primary

  Inner rotors · CPC title