US4814660A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezoelectric motor with multilayer piezoelectric elements
Assignee: NEC Corp
•
Filing: 1988-02-11
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Granted: 1989-03-21
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Expires: 2008-02-11
Abstract
Abstract The specification discloses a piezoelectric motor which comprises an actuator and a rotor. The actuator includes a frame which has at least three arms extending from the center of the frame in a radial direction so that tip portions of the arms are situated on the same circumference. The actuator further includes multilayer piezoelectric elements formed by stacking a plurality of piezoelectric sections along a stack axis. The elements are placed respectively between adjacent arms in the frame so as to make the adjacent arms symmetrical to each other in regard to a line passing through the center and perpendicular to the stack axis. The rotor is supported in a freely rotatable manner around an axis passing through the center of the frame. The rotor has an inner wall inscribed with the tip portions of the arms and is rotated with a driving force generated on the tip portions when driving voltages having a predetermined phase difference from each other are applied to the multilayer piezoelectric elements.
Inventors
- 👤 Hiroaki Yamada
- 👤 Eiichi Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:23
CPC Classifications
H; H02; H02N; H02N2/00; H02N2/0005; H02N2/001; H02N2/002; H02N2/0025; H02N2/10; H02N2/103; H02N2/14; H02N2/145; H02N2/147
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
158 words
A piezoelectric motor comprising; actuator means including a frame which has at least three arms extending from a center of the frame in the radial direction so that tip portions of the arms are situated on the same circumference and multilayer piezoelectric elements formed by stacking a plurality of piezoelectric sections in a stack axis, said elements being placed respectively between adjacent arms in said frame so as to make said adjacent arms symmetrical to each other in regard to a line passing through said center and perpendicular to the stack axis; and rotor means which is supported in a freely rotatable manner around an axis passing through said center of the frame and which has an inner wall inscribed with the tip portions of said arms, said rotor means being rotated with driving force generated on said tip portions when driving voltages having a predetermined phase difference from each other are applied to said multilayer piezoelectric elements.
Claim 2
Dependent Claim
158 words
A piezoelectric motor comprising; actuator means including a frame which has at least three arms extending from a center of the frame in the radial direction so that tip portions of the arms are situated on the same circumference and multilayer piezoelectric elements formed by stacking a plurality of piezoelectric sections in a stack axis, said elements being placed respectively between adjacent arms in said frame so as to make said adjacent arms symmetrical to each other in regard to a line passing through said center and perpendicular to the stack axis; and rotor means which is supported in a freely rotatable manner around an axis passing through said center of the frame and which has an inner wall inscribed with the tip portions of said arms, said rotor means being rotated with driving force generated on said tip portions when driving voltages having a predetermined phase difference from each other are applied to said multilayer piezoelectric elements.
Claim 3
Dependent Claim
29 words
A piezoelectric motor as claimed in claim 1 wherein deformations induced in said multilayer piezoelectric elements are based on a longitudinal electrostrictive effect of said plurality of piezoelectric sections.
Claim 4
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 1 further comprising pressing means for pressing said rotor against said actuator.
Claim 5
Dependent Claim
33 words
A piezoelectric motor as claimed in claim 1 wherein the phase difference of said driving voltages is varied with the number of said multilayer piezoelectric elements and the period of said driving voltages.
Claim 6
Dependent Claim
15 words
A piezoelectric motor as claimed in claim 1 wherein said driving voltages have sinusoidal waveforms.
Claim 7
Dependent Claim
14 words
A piezoelectric motor as claimed in claim 1 wherein said inner wall is tapered.
Claim 8
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 1 wherein said rotor is formed of a sleeve with a bottom.
Claim 9
Dependent Claim
27 words
A piezoelectric motor as claimed in claim 1 further comprising shaft means supported at the center of said actuator to pass through the center of the rotor.
Claim 10
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 8 wherein said shaft is rotatable at the center of the actuator.
Claim 11
Dependent Claim
18 words
A piezoelectric motor as claimed in claim 9 further comprising means for securing said rotor and said shaft.
Claim 12
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 8 wherein said shaft is secured at the center of said actuator.
Claim 13
Dependent Claim
16 words
A piezoelectric motor as claimed in claim 11 wherein said rotor has bearings for said shaft.
Claim 14
Dependent Claim
23 words
A piezoelectric motor as claimed in claim 1 wherein said rotor is mounted on the stator with said tip portions of said arms.
Claim 15
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 13 wherein said rotor is mounted on the stator through said shaft.
Claim 16
Dependent Claim
90 words
A piezoelectric motor comprising: a stator having a base member and an actuator, the actuator having a plurality of recesses and plurality of arms including tip portions; a plurality of multilayer piezoelectric elements secured in the recesses of the actuator; a rotor with an inner wall in contact with the tip portions of the arms of the actuator; and a driving circuit connected to supply driving voltages to the piezoelectric elements to produce a longitudinal electrostrictive effect and deform the piezoelectric elements, thereby deforming the actuator and rotating the rotor.
Claim 17
Dependent Claim
90 words
A piezoelectric motor comprising: a stator having a base member and an actuator, the actuator having a plurality of recesses and plurality of arms including tip portions; a plurality of multilayer piezoelectric elements secured in the recesses of the actuator; a rotor with an inner wall in contact with the tip portions of the arms of the actuator; and a driving circuit connected to supply driving voltages to the piezoelectric elements to produce a longitudinal electrostrictive effect and deform the piezoelectric elements, thereby deforming the actuator and rotating the rotor.
Claim 18
Dependent Claim
15 words
A piezoelectric motor as claimed in claim 15 wherein the driving circuit comprises an oscillator.
Claim 19
Dependent Claim
16 words
A piezoelectric motor as claimed in claim 16 wherein the oscillator comprises a sinusoidal wave generator.
Claim 20
Dependent Claim
17 words
A piezoelectric motor as claimed in claim 16 wherein the driving circuit further comprises a phase shifter.
Claim 21
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 15 wherein the rotor and the stator are made of stainless steel.
Claim 22
Dependent Claim
27 words
A piezoelectric motor as claimed in claim 15 further comprising a shaft fixed to the center of the actuator and wherein the rotor rotates about the shaft.
Claim 23
Dependent Claim
27 words
A piezoelectric motor as claimed in claim 15 further comprising a shaft mounted at the center of the actuator and fixed to the rotor to rotate therewith.
Claim 24
Dependent Claim
38 words
A piezoelectric motor as claimed in claim 15 wherein the plurality of arms consists of three arms, the plurality of recesses consists of three recesses, and the plurality of multilayer piezoelectric elements consists of three multilayer piezoelectric elements.
Claim 25
Dependent Claim
36 words
A piezoelectric motor as claimed in claim 15 wherein the plurality of arms consists of four arms, the plurality of recesses is four recesses, and the plurality of multilayer piezoelectric elements is four multilayer piezoelectric elements.
Claim 26
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 1 further comprising adhesives which secure the piezoelectric elements to the actuator.
Claim 27
Dependent Claim
19 words
A piezoelectric motor as claimed in claim 1 wherein the rotor and the stator are made of stainless steel.
Claim 28
Dependent Claim
18 words
A piezoelectric motor as claimed in claim 1 wherein the actuator is in the shape of a triangle.
References Cited (Backward Citations)
SU851565A1
Cited
US4339682A
Cited
US4455501A
Cited
US4523121A
Cited
US4495432A
Cited
US4622483A
Cited
US4578607A
Cited
US4613782A
Cited
US4585969A
Cited
US4686440A
Cited
US4757223A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |