Patent ID: 8575810
Filing Date: 2013-11-05
Classification: H02K

Abstract:
1. A motor comprising: an annular stator that includes a plurality of permanent magnets, a plurality of stator cores, and a plurality of coils, the permanent magnets and the stator cores being alternately arranged in a circumferential direction of the stator, an annular outer-rotor that is arranged outside the stator, has a rotational axis coincident with a central axis of the stator, and has a plurality of first salient poles; and an annular inner-rotor that is arranged inside the stator, has a rotational axis coincident with the central axis of the stator so as to rotate in conjunction with the outer-rotor, and has a plurality of second salient poles that are equal in number to the first salient poles, wherein the permanent magnets are magnetized in the circumferential direction and extend in a radial direction of the stator, and each of the permanent magnets has one end that is opened toward the outer-rotor in the radial direction and the other end that is opened toward inner-rotor in the radial direction, the coils are each wound by concentrated-winding on a tooth that is constituted from a different one of the permanent magnets and respective parts of two stator cores adjacent to the permanent magnet, the first salient poles are arranged at offset positions relative to the second salient poles in the circumferential direction, the stator cores each have two extending parts and a connecting part, the two extending parts each extending from the inner-rotor toward the outer-rotor in the radial direction and each being the part on which the coil is wound, the connecting part connecting the two extending parts with each other on sides thereof facing the inner-rotor in the radial direction, in a cross section of the motor perpendicular to a direction of the central axis, the extending parts and the permanent magnets each have a first circumferential surface on a side facing the outer-rotor and a second circumferential surface on the side facing the inner-rotor in the radial direction, and the first salient poles and the second salient poles are arranged such that, in the cross section, when an edge forward in a first circumferential direction of a circumferential surface of at least one second salient pole is coincident with an edge forward in a second circumferential direction of a second circumferential surface of an extending part that is adjacent, forward in the first circumferential direction, to a permanent magnet corresponding in position with the second salient pole, at least one first salient pole corresponds in position in the radial direction with a certain portion of the extending part that is adjacent, forward in the first circumferential direction, to the permanent magnet, where the first circumferential direction and the second circumferential direction are circumferential directions of the stator opposite to each other.