2014 Fiscal Year Annual Research Report
潤滑剤の機能性を利用した超音波モータの効率・寿命改善
| Project/Area Number |
14J11842
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
邱 惟 東京工業大学, 大学院総合理工学研究科, 特別研究員(DC2)
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| Project Period (FY) |
2014-04-25 – 2016-03-31
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| Keywords | ultrasonic motor / lubrication / torque / optical interferometry / electrorheological fluid / London |
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| Outline of Annual Research Achievements |
Last year, I mainly finished three tasks in my doctoral study:
1. A bidirectional non-contact piezoelectric motor using a piezoelectric torsional vibrator and the giant electrorheological (GER) fluid was developed;
2. We investigated the torque of ultrasonic motors in lubricated condition, and significant improvement in motor output torque was observed. The maximum torque as high as 1.01 Nm was obtained in a 25-mm-diameter hybrid transducer type ultrasonic motor, which was 2.6 times higher than that in dry condition;
3. A stroboscopic interferometry technique that is capable of measuring transient film thickness variations in an ultrasonic motor contact oscillating at frequencies >50 kHz was developed. This is the first measurement of film thickness at such a high frequency.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The most important finding last year goes to the torque improvement of ultrasonic motors using lubricant, which was not expected before. We experimentally investigated this phenomenon, and believe that this finding will explore the high-torque applications of ultrasonic motors to a great extent.
I also visited the Tribology Group at Imperial College London to investigate the lubrication mechanisms in lubricated ultrasonic motors. I developed the stroboscopic optical interferometry technique using which the transient lubricant film thickness can be measured at frequencies >50 kHz. The obtained results provide preliminary information on the lubrication mechanisms at ultrasonic frequencies.
Furthermore, we found a desirable material - GER fluid - for non-contact piezoelectric motors.
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| Strategy for Future Research Activity |
1. We would like to investigate the lubricating effect in traveling wave ultrasonic motors. This type of ultrasonic motors has different contact mechanics from standing wave ultrasonic motors, and the lubricating effect has not been examined.
2. The lubrication mechanisms in ultrasonic motors will be studied using capacitance measurements, as a supplement to optical interferometry when wear occurs.
3. The lubricants with different Stribeck curves will be applied to ultrasonic motors to find the desirable lubricants and optimize the lubricated ultrasonic motors.
4. The response time of GER fluid will be measured and its frequency response will also be investigated. New driving method for GER fluid-based non-contact piezoelectric motors will be developed.
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