Rotor and rotating electric machine
Provided is a rotor that enables reduction in iron loss due to harmonics. One magnetic pole is formed by arranging three or more magnetic-pole layers each having a pair of V-shaped magnet slots and permanent magnets. An angle between a q axis and a line parallel to a magnetic-flux output surface of the permanent magnet is defined as a magnetic-pole-layer angle. The magnetic-pole-layer angles in one magnetic pole become smaller as the magnetic-pole layers become closer to a rotary shaft. A shortest distance from the magnet slot to the outer circumferential surface of a rotor core is defined as a bridge width and a shortest distance between the adjacent magnetic-pole layers is defined as a magnetic-pole-layer interval. The magnetic-pole-layer interval is set to be smaller than a sum of the bridge widths of the adjacent magnetic-pole layers.
1 . A rotor for a multi-layer V-shaped interior permanent magnet motor comprising a rotor core and a plurality of permanent magnets, the rotor to rotate about a rotary shaft, wherein
in a cross-section perpendicular to the rotary shaft,
one magnetic pole is formed by three or more magnetic-pole layers being arranged, each magnetic-pole layer being formed by a pair of magnet slots in a V shape opened radially outward from a center of the rotary shaft and the permanent magnets inserted in the magnet slots,
each magnet slot has a magnet insertion portion in which the permanent magnet is inserted and flux barriers formed at both ends of the magnet insertion portion to prevent magnetic flux generated from the permanent magnet from returning to the permanent magnet without passing through a stator core,
where a magnetic pole center of the one magnetic pole is defined as a d axis, a direction electrically perpendicular to the d axis is defined as a q axis, and an angle on the rotary shaft side between the q axis and a line parallel to a magnetic-flux output surface of the permanent magnet inserted in the magnet slot in each magnetic-pole layer is defined as a magnetic-pole-layer angle, the magnetic-pole-layer angles in the one magnetic pole become smaller as the magnetic-pole layers become closer to the rotary shaft, and
where a shortest distance from the flux barrier on a radially outer side of the magnet slot to an outer circumferential surface of the rotor core is defined as a bridge width and a shortest distance between the magnetic-pole layers with permanent magnets adjacent to each other is defined as a magnetic-pole-layer interval, the magnetic-pole-layer interval is smaller than a sum of the bridge widths of the magnetic-pole layers adjacent to each other, wherein
a shortest distance between the q axis and the flux barrier on the radially outer side of the magnetic-pole layer closest to the rotary shaft is smaller than the magnetic-pole-layer intervals in the magnetic pole.
2 . The rotor according to claim 1 , wherein
the magnetic-pole-layer intervals in the one magnetic pole become smaller as they approach the rotary shaft.
3 . The rotor according to claim 1 , wherein
the bridge widths in the one magnetic pole become greater as the magnetic-pole layers become closer to the rotary shaft.
4 . The rotor according to claim 1 , wherein
an angle between the d axis and the line parallel to the magnetic-flux output surface of the permanent magnet inserted in the magnet slot in the magnetic-pole layer farthest from the rotary shaft is a right angle.
5 . The rotor according to claim 1 , wherein
where a length of a magnetic-flux output surface of the permanent magnet is defined as a magnet width and a length in a direction perpendicular to the magnetic-flux output surface of the permanent magnet is defined as a magnet thickness, in the one magnetic pole, the permanent magnets in the magnetic-pole layers become smaller in the magnet width and greater in the magnet thickness as the magnetic-pole layers become farther from the rotary shaft.
6 . The rotor according to claim 1 , wherein
in the flux barrier on a radially inner side of the magnet slot in at least one of the magnetic-pole layers,
where the flux barrier is divided into two areas by an extension plane extended from the magnetic-flux output surface of the permanent magnet inserted in the magnet slot, a width in a direction perpendicular to the extension plane of the flux barrier area that is divided by the extension plane and is farther from the d axis is defined as a d-axis radially outer width, and a width in the direction perpendicular to the extension plane of the flux barrier area that is divided by the extension plane and is closer to the d axis is defined as a d-axis radially inner width, the d-axis radially outer width is smaller than the d-axis radially inner width.
7 . A rotating electric machine comprising:
a stator including a stator core and a stator coil; and
the rotor according to claim 1 , which is rotatably provided at the stator with a gap therebetween.