| Project/Area Number |
18K03913
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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 | Kochi University of Technology |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2018: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | 撥水処理 / 気泡 / ディンプル / 摩擦低減 / スラスト軸受 / 超音波法 / 渦電流法 |
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| Outline of Final Research Achievements |
We investigated the potential of a thrust bearing with water-repellent dimples which hold air bubbles in a part of flat hydrophilic plane. Bubbles in the water-repellent dimples with rough surface are difficult to be dragged out to the hydrophilic land even if the hydrophilic surface moves with thin film. If the upper surface of the bubbles is covered with lubricant, the bubble in dimple remains retained even if the end of the moving surface invades into the dimple bubble region multiple times. Improvement of friction characteristics due to fluid slip on the dimple bubbles appears within the range where the pressure flow into the inflow direction due to slip does not become significant. We developed a newly ultrasonic / eddy current composite probe that can simultaneously observe the behavior of such bubbles and the oil film thickness. Then, it became possible to evaluate the lubrication states on the back surface (lubrication surface) of the bearing material 3mm in thickness.
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| Academic Significance and Societal Importance of the Research Achievements |
従来のスラスト軸受にあるマクロな先すぼまり部を持たない，新しいスラスト軸受を提案した．平坦・平滑な棚部を親水化して気泡の保持や成長による広域的な油膜破断を抑制すると同時に，気泡を強固に保持できる粗い撥水凹部を部分的に配置した軸受であり，凹部気泡での流体スリップに伴い発生する圧力による軸受特性改善の可能性を明らかにできた．本研究で得られた上記成果は，近年注目されているディンプルテクスチャの特性向上にも繋がるものである．また，開発した超音波・渦流複合探触子は，従来不可能であった，油膜破断率とそこでの膜厚の同時測定を可能にするものであり，種々の実在軸受の潤滑評価への適用が期待される．
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