Separator for rolling element bearings

A method of forming a separator for a bearing having an inner ring, an outer ring and a plurality of rolling elements disposed between the inner and outer rings, the method comprising the steps of:

• providing a tube of a composite material, the composite material including a mix of a base polymer, reinforcing fibers and lubricant;
• machining the outer surface of the tube to a desired outside diameter of the separator and the inner surface of the tube to a desired inside diameter of a central pocket;
• and
• cutting the tube to provide at least one annular body having a desired thickness of the separator.

A bearing assembly comprising:

• an inner ring having a centerline;
• an outer ring disposed about the inner ring;
• a number N of rolling elements disposed between the inner and outer rings and spaced circumferentially about the centerline so as to define a pitch circle;
• and
• a number X of separators, the number X being equal to one half a value of N, each separator including a body formed of a composite material and having a central pocket sized to receive one of the number N of rolling elements and the number X of separators being disposed about every other rolling element around the pitch circle, each separator body having a first contact end configured to contact an adjacent one of the rolling elements and an opposing, second contact end configured to contact another adjacent one of the rolling elements, the composite material including a mixture of a polymer base, reinforcing fibers and a lubricant;
• wherein the polymer base includes polyetherimide, the reinforcing fibers include short strand carbon fibers in an amount of between ten percent by weight and thirty percent by weight, and the lubricant includes molybdenum disulfide in an amount of between one-half percent by weight and ten percent by weight.