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:
Dec. 08, 1992
Filed:
May. 17, 1991
Applicant:
Inventors:
Fujio Nakagawa, Hirakata, JP;
Masami Wada, Hirakata, JP;
Assignee:
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02K / ;
U.S. Cl.
CPC ...
310 45 ; 310257 ; 310 / ;
Abstract
In a method for manufacturing yokes (3, FIG. 1) to be used in a permanent magnet type stepping motor (10, FIG. 2), a surface-treated dead soft steel sheet such as nickel-plated steel sheet or aluminized steel sheet containing carbon in 0.01 wt. % or less is press-worked to form yoke (3) having plural pole teeth (3a, FIG. 1) on its inner periphery, and then the yoke is annealed in an inactive gas atmosphere in a temperature range of 750.degree.-820.degree. C. to remove residual stress, and permeability of the yoke is improved.