Rotary electric machine
A contour line on the outer circumferential side of each magnet hole in the first layer is formed to be an arc passing through a total of three intersections, i.e., an intersection of a d axis and a reference magnetic flux line which is a magnetic flux line as a reference positioned inward by a predetermined number of magnetic flux lines from the outer circumferential edge of a rotor core, and intersections of: the reference magnetic flux line; and sides at the circumferential ends of the magnet hole which are positioned inward by a bridge dimension from the outer circumferential edge of the rotor core. Thus, a rotary electric machine that enables maximum utilization of reluctance torque and magnet torque and suppression of torque ripple can be obtained with simple processing and low cost.
1. A rotary electric machine comprising a stator and a rotor, wherein
the rotor includes a rotor core having a plurality of magnetic poles formed by inserting permanent magnets into magnet holes formed at regular intervals in a circumferential direction, and
in the case where a magnetic flux flowing along a d axis corresponding to a direction of a center line of each magnetic pole is defined as a d-axis magnetic flux, and a magnetic flux flowing along a q axis corresponding to a direction of a center line between the magnetic poles is defined as a q-axis magnetic flux, a contour line along the circumferential direction of each magnet hole in a cross section perpendicular to a rotation axis of the rotor is formed to be an arc passing through three intersections at which one of magnetic flux lines of the q-axis magnetic flux intersects with a circumferential-center line and circumferential-end sides of the magnet hole,
wherein the magnet hole includes a plurality of magnet holes formed along a radial direction of the rotor, such that the number of magnetic flux lines of the q-axis magnetic flux calculated when the magnet holes are not formed in the rotor core is the same among: a part between an outer circumferential edge of the rotor core and the magnet hole formed on a radially outermost side; a part between a contour line on a radially outer side and a contour line on a radially inner side of each formed magnet hole; and a part between the magnet holes adjacent to each other in a radial direction, wherein the permanent magnet inserted in each magnet hole has four rounded corners, and a radially innermost magnet hole being divided by a bridge, the permanent magnets arranged in the radially innermost magnet holes being spaced apart from the bridge.
2. The rotary electric machine according to claim 1 , wherein the magnet hole includes a pair of a first hole and a second hole which are symmetric with respect to the d axis, such that the three intersections of the first hole and the three intersections of the second hole are located on the same magnetic flux line.
3. The rotary electric machine according to claim 1 , wherein
the permanent magnet inserted in each magnet hole is formed such that a contour line along the circumferential direction of the permanent magnet in a cross section perpendicular to the rotation axis of the rotor is matched with the contour line along the circumferential direction of the magnet hole, and a width in the circumferential direction of the permanent magnet is smaller than a width in the circumferential direction of the magnet hole.
4. The rotary electric machine according to claim 3 , wherein the magnet hole includes a pair of a first hole and a second hole which are symmetric with respect to the d axis, such that the permanent magnets inserted in the first hole and the second hole are located close to the d-axis side with respect to a circumferential center.
5. The rotary electric machine according to claim 3 , wherein a magnetization direction of each permanent magnet is parallel with a line passing through: a center point of an arc forming the contour line on a radially outer circumferential side of the permanent magnet; and a midpoint in the circumferential direction of the contour line.
6. The rotary electric machine according to claim 3 , wherein a magnetization direction of each permanent magnet is a radial direction passing through a center point of an arc forming the contour line on a radially outer circumferential side of the permanent magnet.
7. The rotary electric machine according to claim 1 , wherein
the rotor core is composed of a plurality of rotor blocks divided along an axial direction thereof, and the rotor blocks adjacent to each other are skewed from each other by a skew angle θ in a rotation direction.
8. The rotary electric machine according to claim 7 , wherein the following expression is satisfied:
θ1≤magnetic pole angle−(n−1)×θ,
where θ 1 is an angle formed in the rotation direction by each permanent magnet included in each single rotor block, the magnetic pole angle is a value obtained by dividing 360 degrees by the number of magnetic poles of the rotor, and n is the number of steps of the rotor blocks.