Nidec Corporation

Akira Saiga

Tomotsugu Sugiyama

Hiroyoshi Teshima

Yuji Yabuuchi

Makoto Fujihara

Koji Muraoka

A rotor unit of a brushless motor includes a substantially cylindrical rotor magnet and a rotor holder arranged to retain an outer circumferential portion of the rotor magnet. A stator unit of the same includes a stator core around which coils are wound and a Hall IC for sensing magnetic flux generated from the rotor magnet. The stator core includes teeth disposed at positions separated in the circumferential direction, each of which has an arm portion extending outward in the radial direction around which the coil is wound, and a stretching portion extending from the arm portion outward in the radial direction and in the circumferential direction on both sides. A sensor element included in the Hall IC is positioned in the range within a lead angle of about four degrees or less as a mechanical angle in the circumferential direction from a line connecting radially the central axis and a point bisecting a line connecting neighboring stretching portions, and within a distance of about one millimeter or smaller outward in the radial direction from an arc connecting outer edges of the neighboring stretching portions.

Brushless motor and cooling fan

In a brushless motor of the present invention, by disposing an electronic circuit board and a rotary magnet close to each other, detection precision of a magnetic pole of a Hall IC is enhanced, and a motor can be reduced in thickness. The electronic circuit boardis provided with an opening holeand a notch portionprovided on an outer peripheral side of the opening hole. A lower insulatorof a statoris provided with a positioning surfacewith respect to the electronic circuit boardand an arc projection piece. Portions of coil winding portions of teeth of the statorare fitted into the electronic circuit board, a surface of the electronic circuit boardis brought into positioning against an positioning surfaceof the lower insulator, and the notch portionof the electronic circuit boardand the arc projection pieceof the lower insulatorare engaged with each other.

Growing community of inventors

Kyoto, Japan

Akira Saiga