A comparative thermal analysis of the static performance of different fixed profile bore plain bearings

Abstract

Profile bore bearings are important components in high-speed rotating machinery. In order to provide bearing designers with some useful information on the performances of different bearing profiles, this paper presents a theoretical evaluation of five commonly used types of bearing through a comparison of their steady state performance characteristics. The bearings investigated were two-lobe circular, elliptical (lemon-bore), offset-half, three-lobe and four-lobe types. Their operating characteristics, including the minimum film thickness, maximum temperature, power loss and flowrate, have been calculated using a computerized detailed thermohydrodynamic model developed by the authors. The influences of the shaft speed, specific load, bearing pre-load ratio and lubricant viscosity index on the performance of the bearings have been investigated. In addition, the effect of oil groove angle and load orientation on a four-lobe bearing is briefly examined. Results show that, in general, the performance of the non-circular bearings is inferior to that of the circular bearing; of the non-circular types, the offset-half and elliptical bearings have better overall performances. Also, it is shown that reasonably increasing the angular size of an oil groove has a favourable effect on the static performance of a multi-lobe bearing.