New UHMWPE/Rubber Bearing Alloy

Abstract

A new polymer bearing alloy has been developed that overcomes the high wear nonhydrodynamic deficiencies of UHMWPE when water-lubricated and the shaft wear and high breakaway friction of rubber bearings (Orndorff, Jr., R. L., 1988, “Thermoplastic-Rubber Polymer Alloys and Method for Producing the Same,” United States Patents, 4,725,151 and 4,735,982). Testing covered clean-water high-load and light-load highly abrasive wear testing as well as bearing friction testing. A number of competing materials were also wear tested with the new alloy comparing favorably. Shaft (drum) wear was determined to be zero on the abrasive test. The wear of the polymer alloy decreased by 70% when the high-load sample axial length was reduced by 50% to increase the contact pressure. Rubber bearing wear increased by almost ten times under the same condition. It is hypothesized that the higher-pressure clean-water test sample of the new alloy adjusted to run in the hydrodynamic regime through elastic deflection, creep and a minimal amount of wear. The breakaway coefficient of friction decreased by 67% compared with rubber bearings and the kinetic fiction decreased with increasing load as did the wear. The new alloy will allow water-lubricated rubber bearing length-to-diameter ratios to be reduced from the present value of four to one or less. Projected pressures can be increased five to ten times with the new alloy. [S0742-4787(00)04901-8]