The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 13, 1989
Filed:
May. 28, 1987
Yosuke Takaba, Tokyo, JP;
Tamagawa Seiki Kabushiki Kaisha, Tokyo, JP;
Abstract
A brushless DC motor in which a rotary axis is rotatably mounted in a bearing portion of a stator housing, a rotor yoke is fixedly mounted on an end portion of said rotary axis, a magnet member is mounted on the face of said rotor yoke, a return yoke of ring shape is mounted to one face of said stator housing, a plurality of circumferentially extending cavity portions are formed in said return yoke spaced apart from each other in the radial direction relative to the rotary axis, and a driving coil is positioned facing said rotor yoke. Therefore, core loss caused in said return yoke is reduced by said cavity portions of said return yoke, whereby it is able to obtain high stability at high speed rotation.