US Patent 9343934 Electric motor

An electric motor has a wound stator and a permanent magnet rotor. The rotor includes a shaft, a hub fixed on the shaft, a plurality of rotor core segments and magnets fixed around the hub. The rotor core segment includes at least two rotor blocks inwardly extending from the innermost portion thereof. The hub includes a plurality of hub blocks equidistantly and outwardly extending from the outer surface thereof. The rotor blocks of each rotor core segment engage with at least one hub block to fix the rotor core segment to the hub. The number of rotor blocks is greater than the number of hub blocks.