Patent ID: 7990019

Claim:
An electric motor, comprising: a stator, in which field magnets are fixedly and radially installed on a circular panel-shaped base; a coaxial cylindrical rotor coupled to a shaft, which penetrates through a center of the base, and configured to allow the stator to be located at an inside thereof, the rotor being configured such that magnets, having different polarities to form each pair, are attached on an outer cylinder and an inner cylinder of the rotor and are arranged opposite each other; a cover coupled to the circular panel-shaped base to cover the rotor while causing the shaft of the rotor to penetrate through and protrude from the cover; a rotary magnet plate coupled to the shaft on a top of the cover, and provided with a number of magnets corresponding to a number of pairs of the rotor magnets; magnetic sensors formed on the top of the cover and configured to come into contact with the rotary magnet plate; and a current control device configured to control a magnetization direction of the field magnets of the stator using a rotation angle signal detected by the magnetic sensors, wherein the rotor magnets attached on the outer cylinder and the inner cylinder of the rotor have different polarities to form each pair and are arranged opposite each other, and respective pairs of rotor magnets are arranged on the outer and inner cylinders while being spaced apart from each other by a predetermined interval, the rotor is configured such that the rotor magnets arranged on the outer and inner cylinders form ten pairs, and the stator is configured such that eight field magnets are formed between the outer and inner cylinders of the rotor.