A Possible Criterion for Bearing-Temperature Stresses 320049
THE PAPER suggests a criterion for the tendency toward overheating of plain journal bearings of the high-speed type. The application of a criterion consisting of the product of oil viscosity by the square of the running speed is considered on a heat-balance basis and is compared with a series of observations of crankcase temperatures in a number of typical cars.
Quoting the fact that in a plain journal bearing the coefficient of friction is a function of the term “viscosity times rate of sheer divided by unit load,” the author states the symbols and units employed and analyzes heat generation in the fluid film. An analysis of the dissipation of frictional heat is presented also, together with a discussion of the subject of bearing-temperature estimation.
Curves are presented which resulted from data based on observations taken during a series of tests on a number of representative passenger-cars on the Indianapolis Speedway. In conclusion it is stated that the development presented is believed to be sufficiently logical to warrant the serious investigation of the use of the product μ210V2 as a criterion for temperature rises in high-speed plain bearings.
Major features of the discussion include constructive criticism of the author's premises and methods of analysis, consideration of the effect of counterweighted crankshafts, advocacy that oil men study maximum stress, an analysis of results obtained with a bearing-testing machine, considerations of other actual experimental data and an analysis of oil-film temperature rise.