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Equations have been developed relating friction-power to bearing element temperatures for the particular case of prelubricated or lightly lubricated ball bearings. An expression is derived for the change in relative dimensions of an angular contact bearing, as determined by the temperature gradient across the bearing. A second expression is found for the accommodation of the bearing to expansion, this accommodation resulting from elastic deformation and changes in contact angles. A comparison of these relationships reveals that unstable operating conditions may occur and lead to sudden uncontrollable increases in contact loads. These regions of unstable operation may occur as a result of lubricant degradation or bearing wear, as well as combinations of operating speed and housing dimensions.

This paper describes the most recent of a series of studies on the life of watt-hour meter bearing materials. It covers an investigation of the effect of jewel crystalline axis orientation upon jewel wear. Lifetime stability of meter calibration is a function of bearing wear. A study of the wear (after several years' service) of the sapphire jewel cups of meters in relation to crystalline orientation confirms predictions of another investigator; and a corroborative theory, based upon the physics of crystals, is presented.

In an earlier paper it was shown that mineral oils containing high molecular weight polymer would give better lubrication characteristics (lower friction and lower wear in a V-8 automotive engine) than straight mineral oils of the same viscosity. In this paper, the effects of polymer type, molecular weight and concentration are considered. Generally, friction and wear decrease with polymer concentration, leveling off to a “plateau” which is a characteristic of the given polymer. The level depends on both polymer type and molecular weight, the best results being obtained with the lowest molecular weight polymer. The behavior of polymer/oil blends is also sensitive to the presence of polar surfactants. It is concluded that both the bulk properties of oils, such as viscoelasticity, and surface effects are important in accounting for the advantage of polymer-modified oils. Contributed by the ASLE Technical Committee on Engine Lubrication and presented at the Annual Meeting of the American Society of Lubricati...

Oscillating bearing wear characteristics have been studied under uni-directional steady load conditions using hardened steel pins and bushes. The results are applicable to roller chain and other machine elements employing steel-to-steel oscillating bearing elements. Preliminary friction measurements established that the bearings were operating in a region of mixed lubrication. The load capacity results indicated that a moderate difference in hardness associated with a smooth surface finish gave satisfactory seizure resistance. Minimum wear occurred for equal hardness of pin and bush, although the increase in wear as the hardness difference increased was small. An optimum clearance for minimum wear suggested a balance between surface contact and oil supply factors. In all cases it was found that smooth lapped finishes were less wear-resistant than ground finishes. Variation of maximum surface velocity in discrete steps indicated that low velocity increased the wear and, as the velocity was increased, wear diminished to a constant value.

The effect of lubricants on rear axle pinion bearing break-in has been studied in a motored differential carrier assembly. The pinion torques and lubricant temperatures measured with a multipurpose lubricant were higher than those observed with a lead soap-active sulfur lubricant whereas the bearing wear was lower. Preheat treatment of the multipurpose lubricant was effective in producing more rapid pinion bearing break-in and lower lubricant temperatures. A zinc dialkyldithiophosphate was found to exert a predominant effect on break-in as compared to sulfurized terpenes and chlorinated paraffins when these additives were blended with a straight mineral oil. It has been concluded that a zinc organodithiophosphate may control pinion bearing break-in with the multipurpose lubricant. Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Pittsburgh, Pennsylvania, October 16–18, 1962.

Oils containing polymers have been shown to give better bearing performance—lower friction and lower wear—than straight mineral oils of the same low-shear viscosity, in spite of their non-Newtonian character. This unexpected behavior has been investigated further in studies on solutions of different polymer types, using a range of molecular weights and concentrations for each type and blending all solutions to the same low shear viscosity. The viscosity and elasticity of these solutions were measured at different rates of shear in an ultrasonic crystal viscometer. The governing parameter controlling bearing performance appears to be the recoverable shear, which is related to the elastic modulus of the system. Polymer type, also appears to be important in determining the critical value of recoverable shear required for good bearing performance. Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Rochester, New York, October 15–17, 1963.