US5115161A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic motor
Assignee: NEC Corp
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Filing: 1990-12-03
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Granted: 1992-05-19
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Expires: 2010-12-03
Abstract
Abstract An ultrasonic motor comprises a stator which generates a combined ultrasonic elliptic vibration which is a combined vibration of longitudinal and torsional vibrations, and a rotor which is in press-contact with the stator and driven by the ultrasonic elliptic vibration via a friction force between the rotor and the stator. The stator comprises a first piezoelectric element for generating the longitudinal vibration, a second piezoelectric element for generating the reacting vibration, a headmass having a large stiffness against said longitudinal vibration and a large inertial mass against the torsional vibration, and a rearmass. In the ultrasonic motor, the resonance frequencies of the longitudinal and torsional vibrations are equal, so that the ultrasonic elliptic vibration is generated efficiently on the rotor in a high power state which is adapted in practical use.
Inventors
- 👤 Osamu Myohga
- 👤 Tadao Uchikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:12
CPC Classifications
H; H02; H02N; H02N2/00; H02N2/0005; H02N2/001; H02N2/0045; H02N2/10; H02N2/106
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
90 words
An ultrasonic motor, comprising: a stator for generating an ultrasonic elliptic vibration from a combination of longitudinal and torsional vibrations, said stator including a head mass defined by a first head mass having a stiffness which resists longitudinal vibrations and a second head mass having an inertial mass which resists torsional vibrations, a rear mass and first and second piezoelectric elements positioned between the head mass and the rear mass; and a rotor in press-contact with said stator to receive said ultrasonic vibration via a friction force form said stator.
Claim 2
Dependent Claim
90 words
An ultrasonic motor, comprising: a stator for generating an ultrasonic elliptic vibration from a combination of longitudinal and torsional vibrations, said stator including a head mass defined by a first head mass having a stiffness which resists longitudinal vibrations and a second head mass having an inertial mass which resists torsional vibrations, a rear mass and first and second piezoelectric elements positioned between the head mass and the rear mass; and a rotor in press-contact with said stator to receive said ultrasonic vibration via a friction force form said stator.
Claim 3
Dependent Claim
19 words
An ultrasonic motor, according to claim 1, wherein: said first headmass is made of a light and stiff material.
Claim 4
Dependent Claim
23 words
An ultrasonic motor, according to claim 1, wherein: said first headmass is made of a material selected from Aluminum alloy and Titanium alloy.
Claim 5
Dependent Claim
19 words
An ultrasonic motor, according to claim 1, wherein: said second headmass is made of a highly dense, elastic material.
Claim 6
Dependent Claim
16 words
An ultrasonic motor, according to claim 1, wherein: said second headmass is made of stainless steel.
Claim 7
Dependent Claim
31 words
An ultrasonic motor, according to claim 1, wherein: said headmass is made of a fiber-reinforced alloy in which fibers are deployed in a direction of an axis of said ultrasonic motor.
Claim 8
Dependent Claim
23 words
An ultrasonic motor, according to claim 8, wherein: said fiber-reinforced alloy is Aluminum alloy which includes whiskers of Al 2 O 3 .
Claim 9
Dependent Claim
19 words
An ultrasonic motor, according to claim 1, wherein: said piezoelectric element is a Lead Zirconate Titanate piezoelectric ceramic element.
Claim 10
Dependent Claim
88 words
An ultrasonic motor, comprising: a stator including a head mass, a rear mass, a first piezoelectric element for generating longitudinal vibrations and a second piezoelectric element for generating torsional vibrations, said first and second piezoelectric elements being positioned between the head mass and the rear mass; and a rotor for providing ultrasonic elliptic vibrations in accordance with the longitudinal and torsional vibrations of said stator; wherein said head mass is made of a fiber-reinforced alloy in which fibers are deployed in an axial direction of the ultrasonic motor.
Claim 11
Dependent Claim
88 words
An ultrasonic motor, comprising: a stator including a head mass, a rear mass, a first piezoelectric element for generating longitudinal vibrations and a second piezoelectric element for generating torsional vibrations, said first and second piezoelectric elements being positioned between the head mass and the rear mass; and a rotor for providing ultrasonic elliptic vibrations in accordance with the longitudinal and torsional vibrations of said stator; wherein said head mass is made of a fiber-reinforced alloy in which fibers are deployed in an axial direction of the ultrasonic motor.
Claim 12
Dependent Claim
83 words
An ultrasonic motor, comprising: a stator for generating an ultrasonic elliptic vibration including first and second piezoelectric elements for generating longitudinal and torsional vibrations, a first head mass, a second head mass having a circumferential collar, the first head mass being disposed in a cavity of the second head mass such that the first and second head masses have a common axis; and a rotor in press-contact with said stator to receive the ultrasonic elliptic vibrations via a friction force from said stator.
Claim 13
Dependent Claim
83 words
An ultrasonic motor, comprising: a stator for generating an ultrasonic elliptic vibration including first and second piezoelectric elements for generating longitudinal and torsional vibrations, a first head mass, a second head mass having a circumferential collar, the first head mass being disposed in a cavity of the second head mass such that the first and second head masses have a common axis; and a rotor in press-contact with said stator to receive the ultrasonic elliptic vibrations via a friction force from said stator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-19 | 1995-11-18 | 1996-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-19 | 1999-11-18 | 2000-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-19 | 2003-11-18 | 2004-05-19 | $7700.00 | Window Closed / Lapsed |