Rotor for rotating electric machine

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

a hollow cylindrical rotor core configured to be disposed in radial opposition to a stator of the rotating electric machine, the rotor core having a longitudinal axis and 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; 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 C 1 that radially extends to bisect the magnetic pole in a circumferential direction of the rotor core,

the rotor core further has a plurality of q-axis core portions through which q-axis magnetic flux flows, a plurality of first magnetic flux barriers and a plurality of second magnetic flux barriers,

each of the q-axis core portions is formed between one circumferentially-adjacent pair of the magnetic poles of the rotor and has a centerline L1 that radially extends to bisect the q-axis core portion in the circumferential direction of the rotor core,

each of the first magnetic flux barriers is formed between a corresponding one of the q-axis core portions of the rotor core and a corresponding one of the magnets that are respectively received in the corresponding magnet-receiving holes of the rotor core,

each of the second magnetic flux barriers is formed so as to extend from a centerline C 1 -side end of a corresponding one of the magnet-receiving holes of the rotor core toward the longitudinal axis of the rotor core,

in the rotor core, the following dimensional relationships are satisfied:

W 2 ≧W 1; and

W 3 ≧W 1,

where W 1 is a width between the centerlines L 1 of the q-axis core portions and the corresponding first magnetic flux barriers, W 2 is a width between the centerlines L 1 of the q-axis core portions and the corresponding second magnetic flux barriers, and W 3 is a radial width between a radially inner surface of the rotor core and the second magnetic flux barriers, and

each of the second magnetic flux barriers also extends from a point on the corresponding magnet received in the corresponding magnet-receiving hole of the rotor core in the circumferential direction away from the centerline C 1 of the magnetic pole beyond a radially inner q-axis core portion-side end of the corresponding magnet, the point being closest in the corresponding magnet to the longitudinal axis of the rotor core.

2. The rotor as set forth in claim 1 , wherein each of the second magnetic flux barriers is formed to have a protruding portion that protrudes toward the stator side from the magnet received in the corresponding one of the magnet-receiving holes of the rotor core, and

a protruding height H of the protruding portion from the magnet is set to be in the following range:

0.12 ×R≦H ≦0.29 ×R,

where R is a minimum distance from an intersection P 1 , which is between the centerline C 1 of the magnetic pole and a rotor-side circumferential surface of the stator, to a stator-side wall surface of the corresponding magnet-receiving hole of the rotor core.

3. The rotor as set forth in claim 1 , wherein:

for each pair of the magnet-receiving holes of the rotor core, there is formed corresponding center bridge of the rotor core which radially extends between the two magnet-receiving holes of the pair to separate them from each other, and

in each of the magnet-receiving holes of the rotor core, the corresponding magnet is positioned such that a corner portion of the corresponding magnet abuts a radially-outer root portion of the corresponding center bridge, the corner portion being formed between a radially-outer side surface and a centerline C 1 -side side surface of the corresponding magnet.

4. The rotor as set forth in claim 1 , wherein:

the second magnetic flux barriers extend toward the longitudinal axis of the rotor core such that a radially inward surface of each of the second magnetic flux barriers is closer to the radially inward surface of the rotor core than to the radially outward surface of the rotor core.

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

a hollow cylindrical rotor core configured to be disposed in radial opposition to a stator Of the rotating electric machine, the rotor core having a longitudinal axis and 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; 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 C 1 that radially extends to bisect the magnetic pole in a circumferential direction of the rotor core,

the rotor core further has a plurality of q-axis core portions through which q-axis magnetic flux flows, a plurality of first magnetic flux barriers and a plurality of second magnetic flux barriers,

each of the q-axis core portions is formed between one circumferentially-adjacent pair of the magnetic poles of the rotor and has a centerline L 1 that radially extends to bisect the q-axis core portion in the circumferential direction of the rotor core,

each of the first magnetic flux barriers is formed between a corresponding one of the q-axis core portions of the rotor core and a corresponding one of the magnets that are respectively received in the corresponding magnet-receiving holes of the rotor core,

each of the second magnetic flux barriers is formed so as to extend from a centerline C 1 -side end of a corresponding one of the magnet-receiving holes of the rotor core toward the longitudinal axis of the rotor core,

in the rotor core, the following dimensional relationships are satisfied:

W2≧W1; and

W3≧W1,

where W 1 is a width between the centerlines L 1 of the q-axis core portions and the corresponding first magnetic flux barriers, W 2 is a width between the centerlines L 1 of the q-axis core portions and the corresponding second magnetic flux barriers, and W 3 is a radial width between a radially inner surface of the rotor core and the second magnetic flux barriers,

each of the second magnetic flux barriers also extends from a point on the corresponding magnet received in the corresponding magnet-receiving hole of the rotor core in the circumferential direction away from the centerline C 1 of the magnetic pole beyond a radially inner q-axis core portion-side end of the corresponding magnet, the point being closest in the corresponding magnet to the longitudinal axis of the rotor core; and

a ratio (α/2)/θ is set to be greater than or equal to 9%, where α is the angular width of each of the q-axis core portions of the rotor core, and θ is the angular width of each of the magnetic poles of the rotor.