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:
Mar. 17, 2015
Filed:
Feb. 27, 2008
Shigeki Yanagida, Chuo-ku, JP;
Noboru Ito, Chuo-ku, JP;
Yuuki Aburakawa, Chuo-ku, JP;
Naoki Mori, Chuo-ku, JP;
Yoshihiko Minachi, Chuo-ku, JP;
Shigeki Yanagida, Chuo-ku, JP;
Noboru Ito, Chuo-ku, JP;
Yuuki Aburakawa, Chuo-ku, JP;
Naoki Mori, Chuo-ku, JP;
Yoshihiko Minachi, Chuo-ku, JP;
TDK Corporation, Tokyo, JP;
Abstract
A sintered ferrite magnet having a ferrite phase with a hexagonal structure as the main phase, wherein the composition of the metal elements composing the main phase is represented by the following general formula (1):RCaA(FeM):   (1),x, m, y and z in formula (1) satisfying all of the conditions represented by the following formulas (2)-(6):0.2≦≦0.5:   (2)0.13≦≦0.41:   (3)0.70.15:   (4)0.18≦≦0.31:   (5)9.6≦12≦11.8:   (6),and wherein the density of the sintered ferrite magnet is at least 5.05 g/cm, and the crystal grains of the sintered ferrite magnet satisfy all of the conditions represented by the following formulas (7) and (8), where L μm is the average for the maximum value and S μm is the average for the minimum value among the diameters passing through the center of gravity of each grains in the crystal cross-section parallel to the c-axis direction of hexagonal structures.≦0.95:   (7)1.8≦≦2.5:   (8).