Rotating electric machine and automobile
View Patent ↗A rotating electric machine includes a stator and a rotor. Each of magnetic poles of the rotor includes a magnet insertion hole, a permanent magnet that is inserted in the magnet insertion hole, and a nonmagnetic portion formed between the permanent magnet and an auxiliary salient pole. A portion of the rotor core located toward the stator relative to the nonmagnetic portion function as a bridge portion connecting a magnetic pole peace with the auxiliary salient pole. A side of the nonmagnetic portion located toward the stator includes a first side at the bridge portion, extending along a virtual circular arc passing through the permanent magnet insertion hole closest to the stator, and a side of the nonmagnetic portion located toward the auxiliary salient pole includes a second side extending away from the stator, with the first side and the second side connected through a curved line.
1. A rotating electric machine, comprising:
a stator that includes a stator core and a stator winding wound at the stator core; and
a rotor that is rotatably supported so as to rotate freely relative to the stator and includes a rotor core, with a plurality of magnetic poles formed at the rotor core and auxiliary salient poles formed for reluctance torque generation each between two successive magnetic poles set next to each other, wherein:
each of the magnetic poles of the rotor comprises a magnet insertion hole formed at the rotor core, a permanent magnet that is inserted in the magnet insertion hole, and a nonmagnetic portion formed between the permanent magnet and an auxiliary salient pole;
the permanent magnet is magnetized so as to achieve one polarity of N polarity and S polarity on a stator side thereof and achieve the other polarity on the opposite side wherein a magnetizing direction is reversed at every magnetic pole formed along a circumferential direction of the rotor;
at the rotor, a portion of the rotor core present over an area located toward the stator relative to the permanent magnet functions as a magnetic pole piece and a portion of the rotor core present over an area located toward the stator relative to the nonmagnetic portion function as a bridge portion connecting the magnetic pole piece with the auxiliary salient pole;
a side of the nonmagnetic portion located toward the stator includes a first side at the bridge portion, extending from a side where the permanent magnet is present toward an auxiliary salient pole along a virtual circular arc centered on a rotational axis of the rotor and passing through the permanent magnet insertion hole at a position closest to the stator, and a side of the nonmagnetic portion located toward the auxiliary salient pole includes a second side extending further away from the stator, with the first side and the second side connected through a curved line; and
the first side has a non-projecting circular form concentric to the virtual circular arc centered on the rotational axis of the rotor and passing through a point where a surface of the magnet insertion hole on the outer circumferential side and the first side intersect each other.
2. A rotating electric machine according to claim 1 , wherein:
the second side of the nonmagnetic portion extends substantially along a q-axis magnetic flux passing through the auxiliary salient pole.
3. A rotating electric machine according to claim 1 , wherein:
a ratio of a length of the curved line to a length of the first side is within a range of 0.5 to 2.
4. A rotating electric machine according to claim 1 , wherein:
the nonmagnetic portion includes a third side, located at a surface thereof toward the stator and formed between the first side and the curved line so as to connect the first side and the curved line with a substantially straight line.
5. A rotating electric machine according to claim 1 , wherein:
a thickness of the nonmagnetic portions measured along a radial direction is smaller than a thickness of the magnet measured along the radial direction.
6. A rotating electric machine according to claim 1 , wherein:
a plurality of magnets are inserted in the magnet insertion hole.
7. A rotating electric machine according to claim 6 , wherein:
at least one nonmagnetic portion is formed between the plurality of magnets.
8. A rotating electric machine according to claim 1 , wherein:
the stator winding is wound with a distributed winding method; and
a pole arc rate at the magnet is set within a range of 0.50±0.05 and a pole arc rate at the nonmagnetic portion is set within a range of 0.70±0.05.
9. A rotating electric machine according to claim 1 , wherein:
the stator winding is wound with a concentrated winding method; and
a pole arc rate at the magnet is set within a range of 0.66±0.05 and a pole arc rate at the nonmagnetic portions is set within a range of 0.80±0.05.
10. An automobile, comprising:
a rotating electric machine according to claim 1 ;
a battery that provides DC power; and
a conversion device that converts the DC power from the battery to AC power and supplies the AC power to the rotating electric machine, wherein:
torque generated at the rotating electric machine is used as a drive force.