The combined effects of the centripetal inertia and the surface roughness on the hydrostatic thrust spherical bearings performance

• Published in: Tribology international 2007-03, Vol.40 (3), p.522-532
• Main Authors: Yacout, Ahmad W., Ismaeel, Ashraf S., Kassab, Sadek Z.
• Format: Article
• Language: English
• Subjects: Applied sciences; Bearings, bushings, rolling bearings; Drives; Exact sciences and technology; Externally pressurized bearings; Friction, wear, lubrication; Hydrostatic bearings design; Inertia effect; Machine components; Mechanical engineering. Machine design; Spherical bearings; Surface roughness
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/j.triboint.2006.05.007

This paper deals with the surface roughness and the predominant centripetal inertia terms due to the shaft rotation of the externally pressurized thrust spherical bearings. The solutions are presented for the fitted type of bearings, un-recessed and recessed hemispherical and partial hemispherical seats, with capillary tube and orifice restrictors. On the basis of the stochastic theory, Reynolds equation is developed. The bearing surfaces are assumed to have randomly distributed roughness. Expressions for the pressure distribution, load carrying capacity, volume flow rate, frictional torque, friction factor, power factor, power losses and stiffness factor are obtained. The paper shows the combined effects of the centripetal inertia and the surface roughness on the bearing performance. An optimum design based on the minimum power losses, minimum flow rate and optimal restrictor dimensions is theoretically examined.