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. 03, 2009
Filed:
May. 30, 2005
Kunio Miyashita, Nagano, JP;
Junji Koyama, Nagano, JP;
Muneo Mitamura, Nagano, JP;
Yasuo Sawamura, Nagano, JP;
Kunio Miyashita, Nagano, JP;
Junji Koyama, Nagano, JP;
Muneo Mitamura, Nagano, JP;
Yasuo Sawamura, Nagano, JP;
Harmonic Drive Systems Inc., Tokyo, JP;
Abstract
An insert member () having an identical permeability is fitted in the circular center hole() of a magnetic ring () which is then fitted in the circular hollow section () of a fitting-over member () having an identical permeability. Under that state, the magnetic ring () is placed in a parallel magnetic field. Lines of magnetic flux passing through the magnetic ring () held between the insert member () and the fitting-over member () become linear without substantially inclining against the parallel magnetic field. Under that state, harmonic noise causing a deterioration in detection precision will scarcely appear in the output of a magnetic sensor for detecting the rotating magnetic field of a ring magnet () obtained by performing two-pole magnetization on the magnetic ring (). When the ring magnet () is employed, a deterioration in the detection precision of a magnetic encoder () due to the magnetization state of the ring magnet () can be avoided, and the deterioration in detection precision can be suppressed.