Tapered Roller Bearing Development for Aircraft Turbine Engines.

Abstract : Evaluation tests at speeds to 3.5 million DN were conducted on seven cage designs for high speed tapered roller bearings. These designs were comprised of three geometric and material options and two surface coatings. The race guided Z-type machined from AISI 4340 steel and silver plated proved to be the best design. Performance tests were conducted on both this design and a roller guided cage. The parametric investigation included effects of speed, lubricant viscosity, load, lubricant distribution and cage design on bearing heat generation (torque). Additionally, oil off tests were run to simulate oil supply cessation. Two sets of bearings operating at 1.5 million DN under 2000 lbf. thrust load survived for greater than one minute without impairment of rotational capabilities. (Author)