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:
Jul. 30, 1991
Filed:
Nov. 07, 1989
Yasufumi Yamada, Okazaki, JP;
Yasutaka Nakamori, Anjo, JP;
Kiyomitsu Kozawa, Nagoya, JP;
Yoshimi Natsume, Toyokawa, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
Disclosed is a piezoelectric actuator driving apparatus in which a piezoelectric element used to operate as an electro-mechanical transducer is suitably charged and discharged so that the piezoelectric element can make a predetermined amount of mechanical displacement. In the apparatus, the energy of electric charge causing expansion of the piezoelectric element is controlled by a plurality of pulse signals. Each of these pulse signals acts to store electric charge having a predetermined amount of energy in a capacitor, so that the amount of electric charge stored in the capacitor increases with the increase in the number of the pulse signals. After the total amount of the energy of the electric charge stored in the capacitor attains a predetermined value sufficient to cause expansion of the piezoelectric element, the electric charge stored in the capacitor is supplied to the piezoelectric element. Thus, even when a high speed response and high energy are demanded for controlling the amount of expansion of the piezoelectric element, this demand can be readily dealt with. On the other hand, when the electric charge stored in the piezoelectric element is discharged, voltages applied to the piezoelectric element and the primary and secondary windings of a transformer are controlled so as to prevent deterioration of the piezoelectric element.