Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2002-03-29
2004-09-07
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C417S474000, C310S369000
Reexamination Certificate
active
06787972
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to axial pumps, and more specifically, to axial pumps driven by piezoelectric torsional vibration driven motors.
2. Description of the Background Art
The use of piezoelectric ceramic materials such as lead zirconate titanate (PZT) is well known for applications for sensors, transducers, actuators, and other electromechanical devices.
Many actuators have been developed using electroactive materials, including the torsional actuator disclosed in U.S. Pat. No. 6,020,674. This torsional actuator uses an even number of alternately poled segments of electroactive material which are arranged side by side. The segments are bound together in an integral structure, with conductors positioned between adjacent segments. Under an applied electric field, the torsional actuator produces large angular displacement and a high torque. Similarly, a torsional piezoelectric actuator is described in Glazounov, A. E. Zhang, Q. M., Kim, C. “Piezoelectric Actuator Generating Torsional Displacement from Piezoelectric d
15
Shear Response” Applied Physics Letters 72, pages 2526-2528, 1998.
For some applications, a large rotational motion with a large torque output is demanded. For example, vibration and noise control systems for helicopter rotor blades require an actuator which can provide large amplitude rotational motion with a high torque.
Piezoelectric ultrasonic motors have been developed using traveling wave and standing wave theories which provide higher torque density than electromagnetic motors. An example of the current art in piezoelectric motor technology is provided in “Development of a Two-Sided Piezoelectric Rotary Motor for High Torque”, T. S. Glenn, W. G. Hagwood, SPIE Volume 3041, 1997. These piezoelectric ultrasonic motors are of limited application, however, because they have either lower power density or lower efficiency than conventional electromagnetic motors.
A compact, simple, lightweight motor which uses a torsional actuator as a stator could provide high torque density, high power density, and high efficiency in response to an alternating electric field.
Axial flow pumps with moving shafts within stationary housings are well known in the art for transferring liquids, granular solids, gases, and slurries. These pumps are may be powered by different power sources.
As opposed to most axial flow pumps that operate with moving shafts within stationary housings, the new pump disclosed and claimed operates with helical fan blades attached within the moving housing as a shaft. The shaft is driven by a piezoelectric torsional actuator as described in U.S. Pat. No. 6,020,674, which is incorporated by reference here, and U.S. patent application Ser. No. 09/697,716 claiming priority to provisional application 06/162527 filed Oct. 27, 1999.
It is an object of this invention to provide an axial bidirectional flow pump driven by a full cycle piezoelectric torsional motor which is compact, light, and a high power density device.
REFERENCES:
patent: 3177382 (1965-04-01), Green
patent: 3211931 (1965-10-01), Tehon
patent: 3230505 (1966-01-01), Parker et al.
patent: 3551764 (1970-12-01), Evans
patent: 3982144 (1976-09-01), Rogers et al.
patent: 4379245 (1983-04-01), Goldstein
patent: 4917579 (1990-04-01), Torma
patent: 5481152 (1996-01-01), Buschulte
patent: 6020674 (2000-02-01), Zhang et al.
patent: 0 413 397 (1991-02-01), None
patent: 2-76147 (1990-03-01), None
A. E. Glazounov, Q. M. Zhang, C. Kim. Piezoelectric actuator generating torsional displacement from piezoelectric d15 shear response, Applied Physics Letters, vol. 72, No. 20, May 18, 1998, pp. 2526-2528.
Timothy S. Glenn and Nesbitt W. Hagood, Development of two-sided piezoelectric rotary ultrasonic motor for high torque, Active Materials and Structure Laboratory, Department of Aeronautics and Astronautica, Massachusetts Insititute of Technology, SPIE vol. 3041, 0277-786X/97, p. 326-338, 12/97.
Kim et al, Piezoelectric Ceramic Assembly Tubes for Torsional Actuators, Materials Science and Technology Division, Naval Research Laboratory, Part of the SPIE Conference on Smart Materials Technologies, Newport Beach, California, March 1999, SPIE vol. 3675, 0277-786X/99, pp. 53-61.
Kim et al, High Authority Piezoelectric Torsional Actuators, Materials Science and Technology Division, Naval Research Laboratory, 0-7803-4959-8/98, pp. 277-281.
Kim et al. Composite Piezoelectric Assemblies for Torsional Actuators, Naval Research Laboratory, NRL/MR/6380-97-7997, Mechanics of Materials Branch, Materials Science and Technology Division, Sep. 30, 1997, pp. 1-56.
Kim Chulho
Sanday Santiago C.
Dougherty Thomas M.
Karasek John J.
Mills III John Gladstone
The United States of America as represented by the Secretary of
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