Patent ID: 8026648
Filing Date: 2011-09-27
Classification: H02K

Abstract:
1. An electric machine including a brushless DC motor comprising a stator provided with current-carrying coils and at least one partly magnetizable rotor which is provided with a plurality of permanent magnets in the circumferential direction, each embedded in a magnet retainer between the peripheral surface and shaft of the rotor such that in the radial direction, the permanent magnets are completely encircled by the peripheral surface of the rotor, wherein the permanent magnets are rectangular and are arranged with their narrow sides in the circumferential direction, and wherein the stator has a plurality of stator teeth whose end surfaces of their tooth shoe adjacent to the rotor are constructed as flat and tangential to the circumferential surface of the rotor, wherein at the magnet retainer, material recesses of the rotor extend axially inside the rotor laterally in the circumferential direction of the rotor in such a manner that the permanent magnet protrudes into the material recesses at least with its axial edges adjacent to the peripheral surface of the rotor so that the permanent magnet is wider in the circumferential direction than its appurtenant pole shoe neck of the rotor and abuts against the pole shoe of the rotor with a partial width of its external surface and that the partial width corresponds to a tooth shoe width of a stator tooth in the circumferential direction.