Abstract
This paper describes the film formation properties of polyisobutylene (PIB) lubricant under various surface roughness conditions. PIB lubricant has been proposed as a new type of screw tightening lubricant, however the lubrication mechanism in the screw tightening process is yet to be understood. In this study, the in-situ observation tests were conducted under the starved lubrication condition, in which a thin film lubrication regime was simulated. The results showed that film thickness was greater than the surface roughness. Under the high roughness conditions, the time at which direct contact was prevented was shorter. In addition, the occurrence of wear was related to the lambda ratio Λ and under the high roughness conditions, the friction coefficient increased with time owing to expansion of the wear area. It was also shown that under the fully starved condition, the shear stress did not depend on the shear rate, moreover, its value was constant under all roughness conditions. These results suggest that (i) solid-like PIB film was formed on the contact area under the starved condition and (ii) the formation of a film with a high limiting shear stress potentially inhibits wear. These results were consistent with the results of a tightening test.
| Original language | English |
|---|---|
| Pages (from-to) | 1-12 |
| Number of pages | 12 |
| Journal | Tribology International |
| Volume | 136 |
| DOIs | |
| Publication status | Published - 2019 Aug 1 |
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Keywords
- Lambda ratio
- Lubricant
- Polyisobutylene
- Screw tightening
- Shear properties
- Solidification
- Starvation
- Surface roughness
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Surfaces and Interfaces
- Surfaces, Coatings and Films
Cite this
Effect of surface roughness on film formation properties of screw tightening lubricant PIB. / Otsu, Takefumi; Komatsu, Kyoichi; Hashimura, Shinji.
In: Tribology International, Vol. 136, 01.08.2019, p. 1-12.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of surface roughness on film formation properties of screw tightening lubricant PIB
AU - Otsu, Takefumi
AU - Komatsu, Kyoichi
AU - Hashimura, Shinji
PY - 2019/8/1
Y1 - 2019/8/1
N2 - This paper describes the film formation properties of polyisobutylene (PIB) lubricant under various surface roughness conditions. PIB lubricant has been proposed as a new type of screw tightening lubricant, however the lubrication mechanism in the screw tightening process is yet to be understood. In this study, the in-situ observation tests were conducted under the starved lubrication condition, in which a thin film lubrication regime was simulated. The results showed that film thickness was greater than the surface roughness. Under the high roughness conditions, the time at which direct contact was prevented was shorter. In addition, the occurrence of wear was related to the lambda ratio Λ and under the high roughness conditions, the friction coefficient increased with time owing to expansion of the wear area. It was also shown that under the fully starved condition, the shear stress did not depend on the shear rate, moreover, its value was constant under all roughness conditions. These results suggest that (i) solid-like PIB film was formed on the contact area under the starved condition and (ii) the formation of a film with a high limiting shear stress potentially inhibits wear. These results were consistent with the results of a tightening test.
AB - This paper describes the film formation properties of polyisobutylene (PIB) lubricant under various surface roughness conditions. PIB lubricant has been proposed as a new type of screw tightening lubricant, however the lubrication mechanism in the screw tightening process is yet to be understood. In this study, the in-situ observation tests were conducted under the starved lubrication condition, in which a thin film lubrication regime was simulated. The results showed that film thickness was greater than the surface roughness. Under the high roughness conditions, the time at which direct contact was prevented was shorter. In addition, the occurrence of wear was related to the lambda ratio Λ and under the high roughness conditions, the friction coefficient increased with time owing to expansion of the wear area. It was also shown that under the fully starved condition, the shear stress did not depend on the shear rate, moreover, its value was constant under all roughness conditions. These results suggest that (i) solid-like PIB film was formed on the contact area under the starved condition and (ii) the formation of a film with a high limiting shear stress potentially inhibits wear. These results were consistent with the results of a tightening test.
KW - Lambda ratio
KW - Lubricant
KW - Polyisobutylene
KW - Screw tightening
KW - Shear properties
KW - Solidification
KW - Starvation
KW - Surface roughness
UR - http://www.scopus.com/inward/record.url?scp=85063091688&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85063091688&partnerID=8YFLogxK
U2 - 10.1016/j.triboint.2019.03.020
DO - 10.1016/j.triboint.2019.03.020
M3 - Article
VL - 136
SP - 1
EP - 12
JO - Tribology International
JF - Tribology International
SN - 0301-679X
ER -