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:
Aug. 03, 1993
Filed:
Nov. 29, 1991
Yasuyoshi Honda, Hamamatsu, JP;
Masahiko Komoda, Toyohashi, JP;
Keisuke Honda, Toyohashi, JP;
Toshiaki Miyamoto, Toyohashi, JP;
Yukinobu Tomida, Aichi, JP;
Masanori Sato, Toyohashi, JP;
Ryosuke Suganuma, Aichi, JP;
Hideo Kouzaka, Toyohashi, JP;
Asmo Co., Ltd., Shizuoka, JP;
Honda Electronics Co., Ltd., Aichi, JP;
Abstract
A drive circuit is used in a Langevin type ultrasonic bolt-tightening motor in which a motor drive voltage having a given frequency is applied to a piezo-electric element in a stator section, the resulting longitudinal and torsional vibrations being effective to rotate a motor section. The drive circuit has a longitudinal vibration sensor for detecting the longitudinal vibration in the stator section, a torsional vibration sensor for detecting vibration in the stator section and a frequency controller for controlling the frequency of the motor drive voltage such that the phase difference between the detection signals of the longitudinal and torsional vibration sensors becomes 90 degrees so as to provide maximum efficiency. Thus, the frequency of the motor drive voltage can be feedback controlled to maintain an optimum drive frequency despite the varying of the optimum drive frequency due to changes in various factors.