Grant-in-Aid for Specially Promoted Research
|Allocation Type||Single-year Grants|
Science and Engineering|
|Research Institution||Kyushu Institute of Technology|
KANETA Motohiro Kyushu Institute of Technology, Faculty of Engineering, Professor (90039123)
NISHIKAWA Hiroshi Kyushu Institute of Technology, Faculty of Engineering, Research Associate (40208161)
|Project Period (FY)
2003 – 2007
Completed(Fiscal Year 2007)
|Budget Amount *help
¥215,800,000 (Direct Cost : ¥166,000,000、Indirect Cost : ¥49,800,000)
Fiscal Year 2007 : ¥19,500,000 (Direct Cost : ¥15,000,000、Indirect Cost : ¥4,500,000)
Fiscal Year 2006 : ¥23,400,000 (Direct Cost : ¥18,000,000、Indirect Cost : ¥5,400,000)
Fiscal Year 2005 : ¥50,700,000 (Direct Cost : ¥39,000,000、Indirect Cost : ¥11,700,000)
Fiscal Year 2004 : ¥76,700,000 (Direct Cost : ¥59,000,000、Indirect Cost : ¥17,700,000)
Fiscal Year 2003 : ¥45,500,000 (Direct Cost : ¥35,000,000、Indirect Cost : ¥10,500,000)
|Keywords||Thermal Elastohydrodynamic Lubrication / Film Thichkness / Traction / Film Pressure / Surface Roughness / Film Temperature / Rheology / Tribology / 衝撃負荷 / 往復運動 / 垂直運動 / 潤滑油分子構造 / 油量不足 / 熱物性 / せん断発熱 / 圧縮発熱 / 機械要素|
Isothermal elastohydrodynamic lubrication (EHL) theory has played an important role for improving the working performance, function and durability of machine elements having a concentrated contact between non-conforming surfaces. The basis of non-Newtonian thermal elastohydrodynamic lubrication theory has been established by reconsidering the isothermal EHL theory from the theoretical and experimental viewpoints which consider temperature distributions in all directions in the contact.
1. The limitation of isothermal EHL analysis has been elucidated experimentally. It is also found that the EHL regime is divided into three types, i.e., over flooded, fully flooded and starved.
2. By using transversely oriented ridges, the causes of surface failures have been discussed from experimental viewpoints. A non-Newtonian numerical analysis method for the thermal EHL problems in point contacts has been developed, and the effects of surface roughness on the film thickness profile, distributions of
pressure and temperatures and the traction coefficient have been discussed. Furthermore, the effects of the surface roughness orientation and the ellipticity ratio of the contacts on surface failures have been discussed. Based on the oil film temperature measurements for rough-smooth surfaces, it has been proved that the oil in EHL contacts behaves as a non-Newtonian fluid.
3. The film pressure distribution, which affects the rolling contact fatigue phenomenon, depends on the thermal conductivities of both contacting surfaces, slide-roll ratio and pressure-viscosity coefficient. The compressive heating plays a significant role on the traction coefficient at very low slide-roll ratios.
4. The effects of impact loads under rolling/sliding conditions have been discussed.
5. Tribo-characteristics under reciprocating motion have been discussed from experimental and theoretical viewpoints.
6. Based on the results described in above, the mechanism of oil film breakdown of reciprocating seals, the mechanism of soot wear have been clarified, and a new device, which can detect the dielectric breakdown of the grease EHL film, has been developed. Less