Rotating electric machine
The rotating electric machine includes a stator having a stator winding and a rotor facing the stator in a radial direction. The rotor includes a carrier having a disk-shaped end plate section fixed to a rotating shaft and arranged coaxially with the rotating shaft, and an annular magnet unit arranged coaxially with the rotating shaft. The magnet has a cylindrical magnet holder whose one end in an axial direction is fixed to the end plate section, and a magnet fixed to a peripheral surface on a stator side in the radial direction in the magnet holder and having an alternating polarity in a circumferential direction. The magnet holder is made of a non-magnetic material. In the magnet, an orientation of an axis of easy magnetization on a q-axis is deviated from an orientation parallel to the q-axis.
1. A rotating electric machine comprising:
a stator having a stator winding; and
a rotor facing the stator in a radial direction, wherein
the rotor includes: a carrier having a disk-shaped end plate section fixed to a rotating shaft and arranged coaxially with the rotating shaft; and an annular magnet unit arranged coaxially with the rotating shaft,
the magnet unit includes a cylindrical magnet holder of which one end in an axial direction is fixed to the end plate section; and a magnet fixed to a peripheral surface on a stator side in the radial direction in the magnet holder and having an alternating polarity in a circumferential direction,
the magnet holder is made of a non-magnetic material having a specific gravity smaller than a specific gravity of iron,
in the magnet, an orientation of an axis of easy magnetization on a q-axis is deviated from an orientation parallel to the q-axis,
the carrier is made of a magnetic material,
the end plate section and the magnet are separated by a first distance in the axial direction,
the stator has a cylindrical stator core assembled on an opposite-to-rotor side in the radial direction in the stator winding, and
a second distance in the radial direction between the peripheral surface of the stator core on a side facing the rotor and the peripheral surface of the magnet on a side facing the stator is smaller than the first distance.
2. The rotating electric machine according to claim 1 , wherein
the magnet unit has an end plate fixed on both sides of the holder in the axial direction opposite to the carrier, and
the end plate is made of a non-magnetic material.
3. The rotating electric machine according to claim 2 , wherein the end plate is made of a non-magnetic material having a specific gravity greater than a specific gravity of the holder.
4. The rotating electric machine according to claim 1 , wherein
the rotor is arranged outside the stator in the radial direction,
the magnet unit has a cylindrical outer holder fixed to an outer peripheral surface of the magnet holder, and
a strength of the outer holder is higher than a strength of the magnet holder.
5. The rotating electric machine according to claim 1 , wherein a thickness dimension in the radial direction of the magnet is equal to or less than an arc length of a magnetic flux transfer surface between d-q axes.
6. The rotating electric machine according to claim 5 , wherein in the magnet, when an intersection of the q-axis and the magnetic flux transfer surface is a center point and a circle whose radius is a radial thickness dimension of the magnet is an orientation circle that defines the axis of easy magnetization of the magnet, the magnet covers a quarter circle of the orientation circle.
7. The rotating electric machine according to claim 1 , wherein the magnet is oriented so as to have a linear axis of easy magnetization tilted with respect to a d-axis.