US4812699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drive control device in an ultrasonic vibration motor
Assignee: Nikon Corp
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Filing: 1987-11-06
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Granted: 1989-03-14
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Expires: 2007-11-06
Abstract
Abstract A ultrasonic vibration motor comprises a moving member, a vibration member contacted by the moving member, an electrostrictive device provided on the vibration member, a power supply for applying a periodic voltage to the electrostrictive device to thereby vibrate the electrostrictive device and generate a travelling vibration wave in the surface of the vibration member, a device for detecting the phase difference between the voltage applied to the electrostrictive device and the current flowing into the electrostrictive device, and a device for discriminating a variation in the load of the moving member on the basis of the phase difference.
Inventors
- 👤 Hidehiro Ogawa
- 👤 Kazuyuki Kazami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:06
CPC Classifications
H; H02; H02N; H02N2/00; H02N2/10; H02N2/14; H02N2/142; H02N2/16; H02N2/163
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
125 words
An ultrasonic vibration motor comprising: a moving member; a vibration member contacted by said moving member; electrostrictive means provided on said vibration member; power supply circuit means for applying a pair of periodic voltages having a predetermined phase difference therebetween to a pair of parts of said electrostrictive means, respectively, to generate a travelling vibration wave in the surface of said vibration member; means for detecting a variation in the load of said moving member; and control means for controlling said power supply circuit means to change said phase difference between said pair of periodic voltages so as to generate a standing vibration wave in the surface of said vibration member instead of said travelling vibration wave when said detected load exceeds a reference value.
Claim 2
Dependent Claim
125 words
An ultrasonic vibration motor comprising: a moving member; a vibration member contacted by said moving member; electrostrictive means provided on said vibration member; power supply circuit means for applying a pair of periodic voltages having a predetermined phase difference therebetween to a pair of parts of said electrostrictive means, respectively, to generate a travelling vibration wave in the surface of said vibration member; means for detecting a variation in the load of said moving member; and control means for controlling said power supply circuit means to change said phase difference between said pair of periodic voltages so as to generate a standing vibration wave in the surface of said vibration member instead of said travelling vibration wave when said detected load exceeds a reference value.
Claim 3
Dependent Claim
22 words
An ultrasonic vibration motor according to claim 1, wherein said control means eliminates said phase difference in response to said detecting means.
Claim 4
Dependent Claim
16 words
An ultrasonic vibration motor according to claim 1, wherein said predetermined phase difference is 90 degrees.
Claim 5
Dependent Claim
30 words
An ultrasonic vibration motor according to claim 1, wherein said detecting means detects said variation from a variation in an electrical characteristic of one of said pair of periodic voltages.
Claim 6
Dependent Claim
48 words
An ultrasonic vibration motor according to claim 1 wherein said detecting means includes a detection circuit connected to said power supply circuit means for detecting a phase difference between the phase of the voltage and the phase of the current of one of said pair of periodic voltages.
Claim 7
Dependent Claim
40 words
An ultrasonic vibration motor according to claim 5, wherein said detecting means further includes means for comparing the detected phase difference with a reference phase difference, and produces an output when said detected phase difference exceeds said reference phase difference.
Claim 8
Dependent Claim
37 words
An ultrasonic vibration motor according to claim 1, wherein said detecting means includes a detection circuit connected to said power supply circuit means for detecting variation in the amplitude of one of said pair of periodic voltages.
Claim 9
Dependent Claim
28 words
An ultrasonic vibration motor according to claim 7, wherein said detection circuit produces a detection output when the variation in said amplitude exceeds a predetermined amount of variation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-13 | 1992-09-12 | 1993-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-13 | 1996-09-12 | 1997-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-13 | 2000-09-12 | 2001-03-14 | $7700.00 | Window Closed / Lapsed |