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.

Date of Patent:
Nov. 25, 2014

Filed:

Aug. 27, 2010
Applicant:

Shoji Itomi, Kuwana, JP;

Inventor:

Shoji Itomi, Kuwana, JP;

Assignee:

NTN Corporation, Osaka, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B 7/30 (2006.01); G01R 33/025 (2006.01); G01D 5/14 (2006.01);
U.S. Cl.
CPC ...
G01D 5/145 (2013.01);
Abstract

An angle detection error is prevented by using a columnar permanent magnet that is radially double-pole-magnetized as a rotating angle detecting sensor while preventing a gap between a plurality of magnetic sensors and an end face of the permanent magnet from being narrowed. The permanent magnet is a ferrite magnet or an alnico magnet having a diameter of 4 mm to 20 mm, and an axial length of 3 mm to 5 mm. The plurality of magnetic sensors detects radial magnetic flux densities at positions axially spaced 0.5 mm to 3.0 mm apart from a central portion of the permanent magnet, the central portion having a diameter equal to or smaller than 20% of the magnet diameter to make it possible to perform detection in a range in which a distribution curve of a radial magnetic flux density has a moderate inclination.


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