Patent ID: 8067872

Claim:
A permanent magnet rotor for an electric motor, with which the permanent magnets ( 4 ; 36 ) extend in the inside of the rotor parallel to the rotation axis (X) of the rotor, and grooves open to the outside are formed in the region of the radially outer longitudinal edges ( 8 ; 16 ) of the permanent magnets ( 4 ; 36 ) on the outer periphery of the rotor, said grooves in each case running from one end-side of the rotor to an opposite end side of the rotor in an inclined or in an arcuate manner with respect to the outer longitudinal edge ( 6 ; 18 ) of the adjacent permanent magnets ( 4 ; 36 ) in the peripheral direction, characterized in that each groove ( 6 ; 18 ) includes a middle line that extends from the one end-side of the rotor to the opposite end-side of the rotor and crosses the outer longitudinal edge ( 8 ; 16 ) of the adjacent permanent magnet ( 4 ; 36 ) at least once, the grooves ( 6 ; 18 ) at the outer side of the rotor have a smaller width in the peripheral direction than in a region of the groove ( 6 ; 18 ) which lies radially further to the inside, and the cross-sectional shape of the groove ( 6 ; 18 ) is constant over the length of the rotor, the grooves ( 6 ; 18 ) being arranged such that in each case one groove ( 6 ; 18 ) covers the radially outer longitudinal edges ( 8 ; 16 ) of two circumferentially adjacent permanent magnets ( 4 ; 36 ) in the radial direction.