摘要:

The determination of hydrodynamic film failure has become one of the key aspects in the study of thin film lubrication (TFL) since the hydrodynamic effect of fluid film at nano-scale can be observed with recently developed experimental techniques. In the present paper, the relative optical interference intensity (ROII) technique with a resolution of 0.5 run in the vertical direction has been used to measure the film thickness. Experimental results show that the hydrodynamic effect can be clearly observed even at very low speed if the contact pressure is sufficiently low or if the viscosity of lubricant is comparatively high. When the pressure increases to a certain degree, the film will suddenly drop to the dimension of several layers of molecules and this is where the failure of the fluid film has taken place. For different viscosity of lubricants, the fluid film failure occurs at different rolling speeds and pressures. In addition, when the normal load becomes higher, a higher speed or larger viscosity is required to form the fluid film in the contact region. Finally, the effects of pressure, viscosity, and velocity on the occurrence of fluid film failure have been examined and a relationship involving the three parameters is proposed.Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

ISSN:1040-2004    

DOI:10.1080/10402009908982301

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Tests were run to compare the fatigue life of two-row tapered roller bearings to that of spherical roller bearings. Both bearing types had an outer diameter of 110 mm with the spherical roller bearing having a 22 percent larger dynamic radial load rating than the tapered roller bearings. All tests were run at 165 percent of the respective two-row dynamic radial load ratings. The results show that both the indirect mounting (double cup or outer ring) and the direct mounting (double cone or inner ring) tapered roller bearings gave significantly better fatigue lives than the spherical roller bearings. These results appear to contradict the present ISO 281 standard which assigns a 1.15 bmrating factor to spherical roller bearings compared to a bmrating factor of 1.10 for that of tapered roller bearings.Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

ISSN:1040-2004    

DOI:10.1080/10402009908982302

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Database consists of nondimensional data of load capacity, maximum pressure and its position, flow and power loss factors obtained by solving the full 2-D Reynolds equation including the effect of oil feed features of 360°, 180° grooves and a single oil hole. Aided by the database, dynamically loaded journal bearings are analyzed without solving the Reynolds equation. The database is interpolated linearly. The fluids shear thinning and elasticity are characterized by the power law and Maxwell models. The solutions given by the present method are almost identical to the expensive FDM solution, and the CPU time consumed in the former cases almost can be neglected as compared to the latter cases.

ISSN:1040-2004    

DOI:10.1080/10402009908982303

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor