Rotor for rotating electric machine, magnetic steel sheet for rotating electric machine, and electric vehicle
A rotor for a rotating electric machine is disclosed which includes a rotor yoke including annular magnetic steel sheets stacked in an axial direction having magnet slots into which magnets inserted, Each magnetic steel sheet includes first through-holes to form the first internal cavities; second through-holes, each having a shape fit for each second internal cavity and configured to form part of one of the second internal cavities; and third through-holes, each having a shape for communication between one of the first internal cavities and one of the second internal cavities and to form, with one of the second through-holes, part of the one of the second internal cavities.
1. A rotor for a rotating electric machine, comprising:
a rotor yoke comprising a plurality of substantially annular magnetic steel sheets stacked in an axial direction of a rotation shaft while a plurality of magnet slots are formed therein, and
magnets inserted into the magnet slots,
the rotor yoke comprising
a plurality of first internal cavities formed in the axial direction on an inner circumference side of the magnet slots and
a plurality of second internal cavities provided in the axial direction on an outer circumferential side of the first internal cavities,
each magnetic steel sheet comprising:
a plurality of first through-holes configured to form the first internal cavities;
a plurality of second through-holes, each having a shape fit for each second internal cavity and configured to form part of one of the second internal cavities; and
a plurality of third through-holes, each having a shape allowing for communication between one of the first internal cavities and one of the second internal cavities and configured to form, with one of the second through-holes, part of the one of the second internal cavities,
wherein when a number of poles of the rotor is n, a number of the magnet slots formed is 2n per magnetic steel sheet,
a number of the first through-holes formed is 1.5n per magnetic steel sheet, and
a number of the second through-holes and the third through-holes formed is n per magnetic steel sheet.
2. The rotor for a rotating electric machine according to claim 1 , wherein each second through-hole and each third through-hole are alternately arranged along a circumferential direction of each magnetic steel sheet.
3. The rotor for a rotating electric machine according to claim 2 , wherein every pair of the magnet slots is arranged like an approximately V-shape, an open portion of which faces a center of the rotor; and
each second internal cavity is formed while facing the open portion of the approximately V-shape formed by each corresponding pair of the magnet slots.
4. An electric vehicle comprising a rotating electric machine having the rotor according to claim 1 .
5. An electric vehicle comprising a rotating electric machine having the rotor according to claim 2 .
6. An electric vehicle comprising a rotating electric machine having the rotor according to claim 3 .