1989 Fiscal Year Final Research Report Summary
Study on Oil Film formation of Rough Surfaces in Rolling Contact under Variable Load
| Project/Area Number |
62460089
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械要素
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| Research Institution | Kyushu University |
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Principal Investigator |
ICHIMARU Kazunori Kyushu University, Faculty of Engineering, Professor, 工学部, 教授 (60037760)
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| Co-Investigator(Kenkyū-buntansha) |
MORITA Takehiro Kyushu University, Faculty of Engineering, Assistant, 工学部, 助手 (70175636)
IZUMI Naoshi Kyushu University, Faculty of Engineering, Assoc.Prof., 工学部, 助教授 (60184579)
YAMAMOTO Yuji Kyushu University, Faculty of Engineering, Professor, 工学部, 教授 (10037997)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Rolling Contact / Variable Load / Partial Elasto-hydrodynamic Lubrication / Surface Roughness / Asperity Interaction / Oil Film Formation / Pitting / Running in |
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| Research Abstract |
Two roller tests under variable loading pulsated by an oil pressure type pulsator were conducted, measuring the state of oil film formation by an electric resistance method, and the characteristics of partial elastohydrodynamic lubrication were investigated. Conclusions were as follows.
(1) Effects of squeeze action on the state of oil film formation were recognized by existence of influence of load amplitude upon oil film formation and measuring result of cross-correlation between load cycle and oil film voltage.
(2) In pitting tests which conducted under the synchronized load variation with the rotation of low hardness roller, the surface roughening was caused by break-down of oil film at the load decreasing position where the squeeze effect did not act, and micro-crackings and successive developments to pittings were observed.
(3) It was confirmed that, in the case of integral drive ratio, almost complete improvement of oil film formation is caused by the increase in micro-geometrical conformity between two roller surfaces owing to replica impression of surface roughness, even under variable loading.
(4) Method of analysis of contact stress between two-rollers considering the surface roughnesses was studied and stress concentrations can be calculated in order to clarify the mechanism of pitting.
(5) By running tests of spur gears, cross corelation coefficients between the oil film voltage and the circumferential vibrating acceleration velocity, which correspond to the state of oil film formation and the dynamic load respectively, were calculated and these values were consistent with two-roller test results.
(6) Analysis by ferrograph of test oils sampled during two roller tests was done and the relation between wear particles and running process were investigated. Types of particles which observed were almost normal rubbing wear particles.
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