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:
Jan. 26, 1999
Filed:
Aug. 21, 1997
Seiko Epson Corporation, Tokyo, JP;
Abstract
An efficient permanent magnet rotor for a brushless motor has a yoke (2) formed by laminating many steel sheets (4) so as to provide an even number of magnetic poles projected externally, filed permanent magnets (3) inserted in the magnetic poles, bridges (10) provided at either end of the permanent magnets and having a width, among a first minimum width below which said bridges cannot be punched out without breaking, a maximum width at which an allowable maximum number of magnetic fluxes passes through said bridges, and a second minimum width below which said bridges cannot withstand a centrifugal force caused by rotation of said permanent magnet rotor, (1) equal to or larger than the greater one of the first and second minimum widths and smaller than the maximum width when the first and second minimum widths are equal to or smaller than the maximum width, or (2) equal to or larger than the greater one of the first and second minimum widths when said greater one of the first and second minimum widths is equal to or larger than the maximum width, and (3) equal to or larger than the thickness of each of said steel sheets.