2022 Fiscal Year Final Research Report
Reduction of Oil Film Width in High-Speed Journal Bearings
| Project/Area Number |
18K03909
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 18040:Machine elements and tribology-related
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2023-03-31
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| Keywords | トライボロジー / ロータダイナミクス / 機械要素 / すべり軸受 / ジャーナル軸受 / 浮動ブシュ軸受 / 高速回転 / 油膜幅縮小 |
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| Outline of Final Research Achievements |
Floating bush journal bearings, whose structures are unique, are widely used to support small-sized high-speed rotating machineries. The rotor supported by the bearings generates a self-excited vibration called an oil whip, which can cause dangerous operating conditions. However, the vibration would disappear when the shaft rotational speed is further increased. The applicant presumed that the peculiar phenomenon is due to the reduction of the inner oil film of the bearing and aimed to understand the actual phenomenon and also to develop a theoretical model. Concerning the first objective, based on the measured oil film torque and the observed oil film condition, it was found that the oil film torque actually decreases as the oil film width shrinks. Concerning the second objective, a numerical program was successfully developed that is capable of calculating oil film torque at low rotational speeds.
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| Free Research Field |
トライボロジー
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| Academic Significance and Societal Importance of the Research Achievements |
高速浮動ブシュ軸受の性能を高い精度で解析できる理論モデルの構築は、特異現象の実験報告が行われた1960年代から要望されているが、未だ完成には至っていない。本研究では、その鍵を握る浮動ブシュ内側油膜で生じる実現象を明らかにしている。ジャーナル軸受の研究分野において、油膜幅が縮小することで油膜トルクが実際に減少することを報告した事例はなく、これを明示できた点に学術的意義がある。また、低速回転用の数値解析プログラムに適用した解法はジャーナル軸受への適用実績がなく、これに成功した点も学術的意義がある。実験成果は有意であり、高速回転用の数値解析プログラムの開発に不可欠な理論モデル改良への寄与度は高い。
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