Piezoelectric motor
First Claim
1. A piezoelectric motor, comprising:
- a motor housing;
a motor shaft having an axis and a surface with a plurality of sloped undulations, said shaft extending within said housing and rotatable about its axis;
at least two piezoelectric actuators rigidly fixed within said housing;
activating means connected to said actuators for inducing said actuators to move radially appling a radial force toward the axis of said shaft, said actuator directly contacting the sloped undulation of said shaft surface, the sloped undulation translating the radial force into tangential force to rotate said shaft;
wherein the actuators are positioned such that at least one actuator is in force applying contact with a slopped undulation of said shaft surface at all times.
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Accused Products
Abstract
A rotary motor uses a plurality of radially acting piezoelectric actuators to impart rotation to a motor shaft having surface undulations. Electrical charge distributed to the actuators causes radial actuator motion resulting in contact between the actuators and the sloped sides of the shaft undulations. The slope of each undulation transforms the radial force into tangential force that rotates the shaft. The slope of the shaft undulations provides a mechanical advantage that transforms the slow radial speed of the actuators into greater shaft rotational speed. The shaft undulations can be made in any desired or easily fabricated shape. The electrical actuation control signals can be modified electrically to produce appropriate radial actuator motion to match the undulations of the shaft. Electric charge can be shared among actuators by using switches or other circuitry. Efficiency can be increased further by using acoustic excitation and by using rollers for contact between the actuators and the shaft.
52 Citations
12 Claims
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1. A piezoelectric motor, comprising:
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a motor housing; a motor shaft having an axis and a surface with a plurality of sloped undulations, said shaft extending within said housing and rotatable about its axis; at least two piezoelectric actuators rigidly fixed within said housing; activating means connected to said actuators for inducing said actuators to move radially appling a radial force toward the axis of said shaft, said actuator directly contacting the sloped undulation of said shaft surface, the sloped undulation translating the radial force into tangential force to rotate said shaft; wherein the actuators are positioned such that at least one actuator is in force applying contact with a slopped undulation of said shaft surface at all times. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A rotary piezoelectric motor, comprising:
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a motor housing; a motor shaft having an axis and a surface with a plurality of sloped undulations, said shaft extending within said housing and rotatable about its axis; a plurality of piezoelectric actuators rigidly fixed within said housing and surrounding the surface of said shaft, each of said actuators comprising a body having at least one segment of piezoelectric material, an actuator base connecting said piezoelectric body to said housing, and a crown attached to said piezoelectric body opposite said base; a plurality of rolling elements, each of said rolling elements disposed between a corresponding one of said crowns and said shaft base; activating means connected to each of said piezoelectric segments for inducing said actuators to move radially applying radial force toward the axis of said shaft said actuator directly contacting the sloped undulations of said shaft surface, the sloped undulations translating the radial force into tangential force to rotate said shaft. - View Dependent Claims (10, 11, 12)
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Specification