A compressor crankshaft assembly includes a crankshaft and an eccentric drive pin extending from one end of the crankshaft. The shape of the drive pin viewed into the exposed end of the drive pin is defined by the intersection of a first cylinder that is coaxial with the axis of a substantially cylindrical orbital bearing journaled and installed to receive the eccentric drive pin and a second cylinder that is coaxial with the axis of a substantially cylindrical main bearing journaled and installed to rotatably receive the crankshaft, such that the area defined by the intersecting portion is less than the area defined by either cylinder.

An unbalanced shaft is provided that has a center of mass eccentric to its rotational axis to generate a shaft unbalance. The unbalanced shaft includes a bearing journal having a variable width throughout its circumference, and a multi-row cage having rollers which roll on inner raceways arranged on an outer lateral surface of the bearing journal. The rollers and inner raceways define a load zone, within which a width of each of the inner raceways is greater than an effective length of the rollers idling thereon. At least one of the inner raceways, which extends circumferentially for 360 degrees, has a width throughout that is greater than an effective length of the rollers rolling thereon. For sections outside of the load zone, at least one of the inner raceways has a width less than the effective length of the rollers that roll thereon.

An unbalanced shaft is provided that has a center of mass eccentric to its rotational axis to generate a shaft unbalance. The unbalanced shaft includes a bearing journal having a variable width throughout its circumference, and a multi-row cage having rollers which roll on inner raceways arranged on an outer lateral surface of the bearing journal. The rollers and inner raceways define a load zone, within which a width of each of the inner raceways is greater than an effective length of the rollers idling thereon. At least one of the inner raceways, which extends circumferentially for 360 degrees, has a width throughout that is greater than an effective length of the rollers rolling thereon. For sections outside of the load zone, at least one of the inner raceways has a width less than the effective length of the rollers that roll thereon.