Piezoelectric motors and methods for the production and operation thereof
First Claim
1. A piezoelectric motor for moving a movable element in at least two directions, comprising:
- a resonator having a plane of symmetry;
at least one piezoelectric component connected to the resonator for exciting the resonator to vibrate when an electric signal is applied to the piezoelectric component;
wherein the piezoelectric element is located asymmetrically with respect to the resonator in such a way that the plane of symmetry of the resonator is not a plane of symmetry of the combination of resonator and piezoelectric component to cause the combination of resonator and piezoelectric component to have two distinct frequencies of operation f1 and f2 for moving the movable element; and
resonance/anti-resonance pairs (f1, f1′
) and (f2, f2′
) such that the phase between the electric current and the electric voltage of a sinusoidal electric signal that is applied to the piezoelectric component declines for frequencies of the sinusoidal electric signal that lie inside each of the resonance/anti-resonance pairs.
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Accused Products
Abstract
The invention relates to a piezoelectric motor comprising a piezoelectric component that is connected to a resonator and a two-dimensional resonator that interacts with a movable element, the resonator having principal surfaces that are parallel to each other and that are also identical in shape and size. The invention further relates to methods for producing such piezoelectric motors, wherein the resonators are manufactured by cutting a profiled, extruded bar into lengths or by cutting, preferably by punching, from sheet metal having constant thickness. Finally, this invention relates to a method for exciting such a piezoelectric motor, wherein the excitation frequency or frequencies is/are generated by the control electronics as a function of time in response to the respective peak current and/or in response to the respective phase minimum between current and voltage and/or in response to the change in phase.
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Citations
58 Claims
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1. A piezoelectric motor for moving a movable element in at least two directions, comprising:
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a resonator having a plane of symmetry;
at least one piezoelectric component connected to the resonator for exciting the resonator to vibrate when an electric signal is applied to the piezoelectric component;
wherein the piezoelectric element is located asymmetrically with respect to the resonator in such a way that the plane of symmetry of the resonator is not a plane of symmetry of the combination of resonator and piezoelectric component to cause the combination of resonator and piezoelectric component to have two distinct frequencies of operation f1 and f2 for moving the movable element; and
resonance/anti-resonance pairs (f1, f1′
) and (f2, f2′
) such that the phase between the electric current and the electric voltage of a sinusoidal electric signal that is applied to the piezoelectric component declines for frequencies of the sinusoidal electric signal that lie inside each of the resonance/anti-resonance pairs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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- 29. A piezoelectric motor for moving a movable element, the motor comprising a coil spring on opposing sides of a resonator which is in driving communication with a piezoelectric element, the spring connected to the resonator to elastically urge a contacting portion on the resonator against the movable element.
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34. A method for configuring a piezoelectric motor to have two frequencies of operation for moving a movable element in two opposite directions, the method comprising:
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providing an elongated resonator having a plane of symmetry;
providing a piezoelectric component having a plane of symmetry;
connecting the piezoelectric component to the resonator such that the resonator plane of symmetry and the piezoelectric component plane of symmetry are parallel but offset from each other;
offsetting the resonator plane of symmetry and the piezoelectric component plane of symmetry sufficiently causes the piezoelectric component to excite the elongated resonator to vibrate in a manner that is neither purely longitudinal nor purely bending, and exciting the piezoelectric component with a first and second signal f1 and f2 to cause the motor to move in first and second directions, respectively, with the frequency f1 falling within a wide-band signal having a frequency interval Δ
f1 and with the frequency f2 falling within a wide-band signal having a frequency interval Δ
f2, with the frequency bands Δ
f1 and Δ
f2 falling within the domain of influence of a resonant circuit having an admittance that increases during Δ
f1 and decreases during Δ
f2. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42)
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43. A method for configuring a piezoelectric motor to have two frequencies of operation for moving a movable element in two different directions, the method comprising:
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providing an elongated resonator having an axial symmetry about an axis of symmetry;
providing a piezoelectric component having an axial symmetry about an axis of symmetry;
connecting the piezoelectric component to the resonator such that the resonator axis of symmetry and the piezoelectric component axis of symmetry are coaxial;
configuring the contact surfaces between the piezoelectric component and the resonator to be asymmetric to cause the piezoelectric component to excite the elongated resonator to vibrate in a manner that is neither purely longitudinal nor purely bending;
exciting the piezoelectric component at first and second frequencies of operation f1 and f2 to cause the motor to move in first and second directions, respectively, with the frequency f1 falling within wide band signal having a frequency interval Δ
f1 and with frequency f2 falling within a wide-band signal having a frequency interval Δ
f2, with the frequency bands Δ
f1 and Δ
f2 falling within the domain of influence of a resonant circuit having an admittance that increases within the frequency range Δ
f1 and decreases within the frequency range Δ
f2. - View Dependent Claims (44, 45, 46, 47, 48, 49)
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50. A piezoelectric motor having two frequencies of operation for moving a movable element in two different directions, comprising:
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an elongated resonator having an axial symmetry about a first axis of symmetry;
a piezoelectric component having an axial symmetry about a second axis of symmetry, the piezoelectric component being connected to the resonator and exciting the elongated resonator to vibrate in a manner that is neither purely longitudinal nor purely bending;
a resonant circuit in electrical communication with the piezoelectric component and exciting the piezoelectric component at first and second frequencies of operation f1 and f2 to cause the motor to move in first and second directions, respectively, with frequency f1 falling within wide band signal 1 having a frequency interval Δ
f1 and with frequency f2 falling within wide-band signal Δ
f2, with the frequency bands Δ
f1 and Δ
f2 falling within the domain of influence of the resonant circuit having an admittance that increases within the frequency range Δ
f1 and decreases within the frequency range Δ
f2. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58)
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Specification