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:
May. 20, 2008
Filed:
Feb. 27, 2006
Kunio Miyashita, Azumino, JP;
Junji Koyama, Azumino, JP;
Muneo Mitamura, Azumino, JP;
Yasuo Sawamura, Komagane, JP;
Kunio Miyashita, Azumino, JP;
Junji Koyama, Azumino, JP;
Muneo Mitamura, Azumino, JP;
Yasuo Sawamura, Komagane, JP;
Harmonic Drive Systems Inc., Tokyo, JP;
Abstract
A motor encoder is mounted on a motor shaft of a geared motor, and the origin position is detected by using a Z-phase signal. An absolute value encoder with a precision that allows the number of motor rotations to be determined is mounted on an output shaftof a reduction gear, and the absolute rotational position thereof is detected. When the first Z-phase signal generated in conjunction with the rotation of the motor shaftis obtained at startup and at other times, the mechanical starting point at which the motor shaft and output shaft are both positioned at the origin can be calculated based on the absolute rotational position of the reduction-gear output shaft obtained from the output-side absolute value encoder. Since the mechanical starting point is obtained by rotating the motor shaft a single rotation at most, the time required to calculate the mechanical starting point is short in comparison with conventional examples, and extraneous rotational movements can be avoided.