Piezoelectric rotation driving apparatus

• US 5,712,524 A
• Filed: 12/26/1995
• Issued: 01/27/1998
• Est. Priority Date: 12/27/1994
• Status: Expired due to Fees

• Current Assignee: Reltec Corporation (GEC, Inc.), NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Suga, Michihisa
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US08/578,320
• Time in Patent Office: 763 Days
• Field of Search: 310/328, 310/323
• US Class Current: 310/328
• CPC Class Codes: H02N 2/101 using intermittent driving, e.g. step motors

Abstract

The present invention provides a piezoelectric rotation driving apparatus wherein the number of the piezoelectric driving bodies is reduced so as to reduce the size of the apparatus. The apparatus is capable of achieving high efficiency and high torque by extinguishing an inertia rotation period. In are preferred embodiment of the invention, a set of the piezoelectric driving bodies including stacked piezoelectric elements are pressed against a cylindrical rotation body serving as a rotor, which is fitted to a rotation shaft, with leaf springs. The piezoelectric driving bodies are combined integrally with each other by a fitting pin such that action directions of forces of action members in the piezoelectric driving bodies driven by the stacked piezoelectric elements are opposite to each other.

Claims

1. A piezoelectric rotation driving apparatus comprising at least one set of piezoelectric driving bodies,

each of said piezoelectric driving bodies including:

an action member having an action surface contacting with a rotor, a base member connected to said action member at a fulcrum portion thereof by a first hinge, said fulcrum portion enabling said action member to move rotatively, a piezoelectric element, one end of which is connected to said action member by a second hinge, and the other end of which is connected to said base member by a third hinge, said piezoelectric element expanding by being applied with a voltage and driving said action member thereby moving said action surface rotatively;

wherein said at least one set of the piezoelectric driving bodies is adapted integrally in the apparatus such that action surfaces of the piezoelectric driving bodies of the at least one set of driving bodies are disposed on the same line and in parallel to a central axis of said rotor and respective rotational displacement directions of said action surfaces are opposite to each other, and said action surfaces are thrust toward the central axis of said rotor by an elastic force of an elastic member.

2. The piezoelectric rotation driving apparatus as claimed in claim 1, wherein applications of voltages to piezoelectric elements of said at least one set of the piezoelectric driving bodies is performed at a timing wherein application of voltage to one piezoelectric element is begun in accordance with rotation direction of the rotor, and application of voltage to the other piezoelectric element is begun when half of a voltage application period of one piezoelectric driving body has passed.

3. The piezoelectric rotation driving apparatus as claimed in claim 1, wherein plural sets of piezoelectric driving bodies integrated with each other are disposed along the central axis of the rotor.

4. The piezoelectric rotation driving apparatus as claimed in claim 1, wherein plural sets of piezoelectric driving bodies integrated with each other are disposed around the rotor.

5. A piezoelectric rotation driving apparatus comprising:

at least one set of piezoelectric driving bodies;

wherein each of said piezoelectric driving bodies includes;

an action member having an action surface contacting with a rotor a base member connected to said action member at a fulcrum portion thereof by a first hinge, said fulcrum portion enabling said action member to move rotatively, a piezoelectric element, one end of which is connected to said action member by a second hinge, and the other end of which is connected to said base member by a third hinge, said element expanding by being applied with a voltage and driving said action member thereby moving said action surface rotatively;

and wherein said rotor includes a rotating shaft and a flange portion extending from said rotation shaft perpendicular to said rotation shaft;

the piezoelectric driving bodies are arranged around said rotation shaft and along an axis line thereof;

action surfaces of each of said piezoelectric driving bodies are disposed on a side surface of said flange at intervals; and

said action surfaces of each of said piezoelectric driving bodies are pressed against the side surface of said flange portion by an elastic force of an elastic member.