| Project/Area Number |
10450064
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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 | 一般 |
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| Research Field |
設計工学・機械要素・トライボロジー
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| Research Institution | Gifu University |
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Principal Investigator |
FUJII Hiroshi Department of Mechanical and Systems Engineering, Faculty of Engineering, Gifu University Professor, 工学部, 教授 (80021583)
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| Co-Investigator(Kenkyū-buntansha) |
SASE Naoki Department of Mechanical Engineering Toyama Institute of technology Associate Professor, 助教授 (10196199)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1999: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | screw / fastener / anti-loosening / helix / bolt / thread / Step-Lock Bolt / rolling dies / ねじ / ゆるみ / 階段状つるまき線 / ステップロックボルト / フランク面上相対すべり / トルク計 / ゆるみ試験機 / 転造用ダイス |
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| Research Abstract |
The authors propose a new type of helix for anti-loosening screw fastener, the way to manufacture it and the evaluation of its performance. Loosening tests for conventional screws and so-called anti-loosening nuts are first reported and discussed. It is shown that human beings have not yet succeeded in the prevention of loosening of screw fasteners without sacrificing some of their important features. The mechanism of loosening is discussed and the two main factors that cause loosening are outlined. The first is due to the relative slip between the bolt threads and the nut threads, while the second is due to the relative slip between the bearing surface of the nut and the surface of the fastened material. A new screw shape that aims at suppressing the former factor is proposed and a method for producing the appropriate threads on the bolt is discussed. The new shape is named "Step-Lock Bolt." The performance of the bolt with this shape is examined to prove the efficacy of the idea.
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