Patent ID: 8217540
Filing Date: 2012-07-10
Classification: F04D,H02K

Abstract:
1. An electric motor with a stator and an external rotor, comprised of a rotor bell and a rotor cover acting as a fan wheel, the rotor bell having a bell floor with a first circumference defined by a first radius, and with a plurality of apertures in the bell floor, and the rotor cover having a plurality of exhaust ports, wherein the rotor cover is plate-shaped and has a plate base and an annular wall, the plate base having a second circumference defined by a second radius substantially equal to the first radius, wherein the exhaust ports in the annular wall are evenly distributed and positioned on the annular wall in an area of lowest air pressure during operation of the electric motor, wherein the plate base of the rotor cover is substantially closed and an inner surface of the plate base of the rotor cover facing the rotor bell has a plurality of radially extending interior blades that are fixedly connected to the plate base, wherein two adjacent of the interior blades, together with the annular wall and the plate base of the rotor cover and the bell floor of the rotor bell form a flow chamber, and each exhaust port in the annular wall is assigned to at least one flow chamber.