2006 Fiscal Year Final Research Report Summary
Studies of Thread-Loosening Keeping Cases of Car's Wheel Tightening in Mind
| Project/Area Number |
17560119
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Design engineering/Machine functional elements/Tribology
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| Research Institution | SHINSHU UNIVERSITY |
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Principal Investigator |
KASEI Shinji SHINSHU UNIVERSITY, Faculty of Engineering, Professor, 工学部, 教授 (90016791)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Threaded Joint / Small Bearing Surface Slip / Self-Loosening Mechanism / Wheel and Hub / Loosening Test Machine / Locking Performance / Wheel Nut |
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| Research Abstract |
Cases of car's wheel tightening being kept in mind, following subjects concerning thread-loosening were examined.
1. Loosening mechanism under repeated slips at bearing surface : A close connection between an elastic torsion of a bolt shank accompanied with a repeated transverse load and a loosening rotation was clearly explained using experimental data. Works consumed at a mating portion of threads and a bearing surface, which mean an energy loss, were experimented and considered. An explanation was done how the loosening rotation occurs and goes forward.
2. Circular reciprocating type loosening test machine : In taking shapes of wheel tightening parts for a model, a new type test machine was designed and manufactured. This machine has four test parts located on the same circumference to enable simultaneous comparison tests, and enables tests under repetition of small amount of slip at bearing surfaces..
3. Influences of the kind of nut etc. to locking performance : concerning various co
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nditions such as the kind of nut, loosening tests under repetition of small amount of slip at bearing surfaces were performed to compare locking performance. Among the present test samples, completeness in performance can not be expected except a nut with locknut (so-called "double-nut") given proper locking operation. Longer grip length undoubtedly makes situation safer.
4. Scattering of a bolt's axial tension in using a manual torque tool : It is pointed out that the misalignment between bolt's axes and tool's rotation axes and use of one-hand type tool are major factors bringing large scatter of the axial tension.
5. Distribution of bearing surface pressure of tapered nuts : this kind of nut being picked up as the typical wheel nut, FEM analyses were carried out. In particular, influences of deviation of the taper angle to this theme were made clear and some problems to be examined were pointed out.
6. Installation methods of disk wheels for cars : Basing on the results and knowledge obtained from studies involving this study, the prescriptions of JIS concerning this subject were considered. Matters, to be questionable or taken notice, were summarized. Less
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Research Products
(8 results)
