US Patent 7893579 Brushless electric motor

An electric motor has a stator (224) having a bearing tube (238) made of a magnetically transparent material; it also has a rotor (222) having a rotor shaft (234) that is at least partially journaled in the bearing tube (238), and has a ring magnet (250) that is fixedly arranged on the rotor shaft (234) inside the bearing tube (238). Two magnetic-field-dependent analog sensors (248′, 248″) are arranged on a circuit board (246) outside the bearing tube (238), at an angular distance (PHI) from one another, in order to generate rotor position signals as a function of the rotational position of the ring magnet (250). A corresponding device (150) that serves to control the motor is provided, in order to process these rotor position signals into a signal that indicates the absolute rotational position of the rotor (222).