PROCEDURE FOR CALCULATING PLASTIC SLIDE BEARINGS UNDER LIMITED LUBRICATION CONDITIONS,
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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A method for calculating the slip effects of plastic bearings under limited lubrication conditions is developed. The effects of specific pressure, slip velocity, and friction are analyzed. Published data on these effects are presented for polyamide bearings. The chief drawback of experimental techniques in evaluating the influence of pressure is the assumption that the friction coefficient is constant and does not depend on the operating conditions. Temperature changes during the slip of plastic bearings are considered and a heat transfer equation is given. Load bearing ability and maximum operating temperature are selected as criteria of plastic bushing or bearing performance. Load bearing ability at different velocities is related to compressive loads and thermal stress resistance, the latter because of the low thermal conductivity of plastics and the resultant high thermal differences at high velocities. A schematic diagram shows how the load is distributed on a bearing for a given gap spacing and arc of contact between shaft and bearing. Friction coefficients, and mechanical and physical properties of four different plastic bearing materials are presented.
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