Rotor for rotating electric machine

1. A rotor for a rotating electric machine, the rotor comprising:

a rotor core configured to be disposed in radial opposition to a stator of the rotating electric machine, the rotor core having a plurality of pairs of magnet-receiving holes formed therein, each pair of the magnet-receiving holes being arranged in a substantially V-shape that opens toward the stator side, the substantially V-shape having its two sides respectively extending in width directions of the two magnet-receiving holes of the pair; and

a plurality of magnets each of which is received in a corresponding one of the magnet-receiving holes of the rotor core,

wherein

for each pair of the magnet-receiving holes of the rotor core, the two corresponding magnets which are respectively received in the two magnet-receiving holes of the pair are arranged so as to together form one magnetic pole of the rotor, the magnetic pole having a centerline C1 that extends in a radial direction of the rotor core and bisects the magnetic pole in a circumferential direction of the rotor core,

the rotor core further has, for each of the magnet-receiving holes, a magnetic flux barrier that is formed, at a centerline C1-side end of a stator-side wall surface of the magnet-receiving hole, so as to protrude from the stator-side wall surface toward the stator side, the stator-side wall surface extending in the width direction of the magnet-receiving hole, and

a protruding height H of the magnetic flux barrier from the stator-side wall surface of the magnet-receiving hole in a direction perpendicular to the stator-side wall surface is set to be in the following range:

0.12 ×R≦H≦ 0.29 ×R,

where R is a minimum distance from an intersection P1, which is between the centerline C1 of the magnetic pole and a rotor-side circumferential surface of the stator, to the stator-side wall surface of the magnet receiving hole.

2. The rotor as set forth in claim 1 , wherein the following dimensional relationships are further satisfied:

0.12 ×D≦W ; and

X≦ 0.1 ×D,

where D is a distance from an intersection P2 between an imaginary line L1 and the rotor-side circumferential surface of the stator to an intersection P3 between the imaginary line L1 and the centerline C1 of the magnetic pole, the imaginary line L1 being defined to extend along the stator-side wall surface of the magnet-receiving hole and tangent to an imaginary circle whose radius is equal to the minimum distance R and center is located at the intersection P1,

W is a width of the magnetic flux barrier in the width direction of the magnet-receiving hole, and

X is an overlapping width over which the magnetic flux barrier and the corresponding magnet overlap each other in the direction perpendicular to the width direction of the magnet-receiving hole.

3. The rotor as set forth in claim 2 , wherein a centerline C1-side end of the corresponding magnet is interposed between opposite ends of the magnetic flux barrier in the width direction of the magnet-receiving hole so that the overlapping width X is greater than 0.

4. The rotor as set forth in claim 1 , wherein the rotor core further has, for each pair of the magnet-receiving holes, a corresponding center bridge that extends in the radial direction of the rotor core between the two magnet-receiving holes of the pair to separate them from each other,

for each of the magnet-receiving holes, there is also formed a protrusion that protrudes from the corresponding center bridge inward of the magnet-receiving hole, so as to position the corresponding magnet in the magnet-receiving hole, and

the protrusion is radially offset from a radial center position of the corresponding center bridge toward the stator side.

5. The rotor as set forth in claim 1 , wherein each of the magnets is a grain boundary diffusion magnet.