| Project/Area Number |
09555077
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Dynamics/Control
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| Research Institution | Nagoya University |
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Principal Investigator |
MITSUYA Yasunaga Nagoya University, Micro System, Professor, 工学研究科, 教授 (10200065)
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| Co-Investigator(Kenkyū-buntansha) |
OHSHIMA Yasuji Nagoya University, Micro System Engineering, Assistant Professor, 工学研究科, 助手 (60293651)
MATSUNAGA Shigeki Nippon Seiko Co. Ltd, R&D Lab., Researcher, 総合研究所, 科学研究員
OHKA Masahiro Shizuoka Inst. of Tech., Mechanical Engineering, Associate Professor, 理工学部, 助教授 (50233044)
野村 由司彦 三重大学, 工学部, 教授 (00228371)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥5,500,000 (Direct Cost: ¥5,500,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Magnetic fluid / Damping Coefficient / Variable damping / Vibration Control / Damper / Magnetic field analysis / Sensitivity in variation of damping / Swing mode |
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| Research Abstract |
To develop ultra-accurate vibration control devices by applying magnetic fluid exhibiting giant variable damping to dampers for machine elements, first mechanism of manifestation of damping was clarified, then damping characteristics were quantified, and finally the feasibility of vibration control using the current on-off control was demonstrated.
1. Clarifying damping mechanism : Special experimental apparatus was set up from a rotating shaft with magnetic poles, a cylinder fixed to a base and magnetic fluid filled inside the gap between the shaft and cylinder. Using this apparatus, the amount of variation of damping was measured. The damping was found to increase in proportion to magnetic field strength in the gap up to as much as ten times larger than the saturated magnetic flux density of magnetic fluid. This revels that the origin of the damping is the formation of clusters of magnetic particles.
2. Quantifying damping characteristics : New findings were obtained from experiments performed using magnetic or nonmagnetic cylinders with the clearance as a parameter. Those are a) the variation rate of damping, i.e., sensitivity of the variation, decreases with increase in the amplitude and frequency, b) the sensitivity slightly increases with decrease in the clearance, c) there is a critical velocity where the damping begins to decrease rapidly with increase in the velocity.
3. Confirming vibration control : To evaluate vibration control performance, two vibrators of parallel- and swing-modes were assembled. Experiments using the current on-off control by the amounts of the amplitude and velocity indicated the applicability of magnetic fluid to vibration control.
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