Abstract: Commutator of the present invention includes electrically conductive part, resin part, ceramic part, first mixing part and second mixing part. First mixing part contains an electrically conductive material and a ceramic material in mixture. In first mixing part, a content of the electrically conductive material decreases and a content of the ceramic material increases from electrically conductive part toward ceramic part. Second mixing part contains the ceramic material and the resin material in mixture. In second mixing part, a content of the ceramic material decreases and a content of the resin material increases from ceramic part toward resin part.

Abstract: Commutator of the present invention includes electrically conductive part, resin part, ceramic part, first mixing part and second mixing part. First mixing part contains an electrically conductive material and a ceramic material in mixture. In first mixing part, a content of the electrically conductive material decreases and a content of the ceramic material increases from electrically conductive part toward ceramic part. Second mixing part contains the ceramic material and the resin material in mixture. In second mixing part, a content of the ceramic material decreases and a content of the resin material increases from ceramic part toward resin part.

Abstract: Electric motor includes stator, rotor, a pair of bearings, outer-ring conducting part, and printed circuit board. Outer-ring conducting part electrically couples outer rings to each other that are included respectively in the pair of bearings. Printed circuit board includes drive circuit and an impedance element. Drive circuit includes ground line. Drive circuit controls an electric current that flows through stator winding. The impedance element is formed with at least not smaller than one pair of conductive patterns. One of the conductive patterns forming the impedance element is electrically coupled with outer-ring conducting part. The other of the conductive patterns forming the impedance element is electrically coupled with ground line included in drive circuit.

Abstract: Electric motor includes stator, rotor, a pair of bearings, outer-ring conducting part, and printed circuit board. Outer-ring conducting part electrically couples outer rings to each other that are included respectively in the pair of bearings. Printed circuit board includes drive circuit and an impedance element. Drive circuit includes ground line. Drive circuit controls an electric current that flows through stator winding. The impedance element is formed with at least not smaller than one pair of conductive patterns. One of the conductive patterns forming the impedance element is electrically coupled with outer-ring conducting part. The other of the conductive patterns forming the impedance element is electrically coupled with ground line included in drive circuit.

Abstract: A molded motor of the present invention comprises: a stator having a stator core wound with a winding and molded with a molding resin; a rotor including a rotary body having a ferrite resin magnet which is a permanent magnet, disposed in a circumferential direction and confronting the stator, and a shaft penetrating through an axial center of the rotary body; a pair of bearings supporting the shaft; a pair of electrically-conductive brackets securing the bearings; and conductive pins which is connecting parts that electrically connect the pair of brackets. The rotor is provided with a first dielectric layer between the shaft and an outer peripheral surface of the rotary body, and a second dielectric layer between the shaft and the bearings.

Abstract: At least one of a shaft and a bearing of a fluid dynamic bearing unit includes an additive-providing portion including the additive on a surface thereof. The lubricating oil is retained between the shaft and the bearing, and contacts the surface of the additive-providing portion. The additive-providing portion is for example a joining member such as adhesive, a housing made of resin, a sleeve made of porous material, an oil repellent coating made of oil repellent agent, and a lubricating coating.