Voice coil-type linear motor
AssigneeHitachi Metals, Ltd.
InventorsTeruo Umehara, Hiroyuki Daicho, Seiki Taketomi
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Abstract
A voice coil-type linear motor comprising an cylindrical outer yoke made of a ferromagnetic material; a cylindrical center yoke made of a ferromagnetic material and magnetically coupled with the outer yoke; an integral, cylindrical magnet consisting essentially of an R-B-Fe alloy wherein R is at least one of rare earth metals such as Nd, Pr and Dy and having magnetic anisotropy in a radial direction, the cylindrical magnet being fixed to an inner surface of the outer yoke; a protective member made of a nonmagnetic and conductive material and fixed to a surface of the cylindrical magnet; and a movable coil means arranged in a magnetic gap between the center yoke and the cylindrical magnet.
Claims10
A voice coil-type linear motor comprising an cylindrical outer yoke made of a ferromagnetic material;
- a cylindrical center yoke made of a ferromagnetic material and magnetically coupled with said outer yoke;
- a circumferentially integral, cylindrical magnet consisting essentially of an R-B-Fe alloy wherein R is at least one of the rare earth metals such as Nd, Pr and Dy and having magnetic anisotropy in a radial direction, said cylindrical magnet being fixed to an inner surface of said outer yoke;
- a movable coil means arranged in a magnetic gap between said center yoke and said cylindrical magnet;
- and combined means for protecting said cylindrical magnet against physical contact-induced cracking and for compensating for the variation in inductance of said movable coil means during motor operation.
A voice coil-type linear motor comprising an cylindrical outer yoke made of a ferromagnetic material;
- a cylindrical center yoke made of a ferromagnetic material and magnetically coupled with said outer yoke;
- a circumferentially integral, cylindrical magnet consisting essentially of 10-30 atomic % of R wherein R is at least one of the rare earth metals such as Nd, Pr and Dy, 2-28 atomic % of B and 65-80 atomic % of Fe and having magnetic anisotropy in a radial direction, said cylindrical magnet being coated with an anti-oxidizing layer and fixed to an inner surface of said outer yoke;
- a movable coil means arranged in a magnetic gap between said center yoke and said cylindrical magnet;
- and combined means for protecting said cylindrical magnet against physical contact-induced cracking and for compensating for the variation in inductance of said movable coil means during motor operation.
Dependencies are inferred from the claim text.