Concentric radii ball bearing stack

1. A ball bearing stack, comprising:

more than one bearing arranged in face to face relation and sharing a common rotational axis, each bearing having an inner ring and a concentric outer ring, the inner ring defining an inner race, the outer ring defining an outer race, with a plurality of ball bearings captured within an annular space defined between the inner race and the outer race; and

each of the more than one bearing having a ball bearing contact surface on the outer race which is radiused from face to face about a common centre point positioned on the common rotational axis.

2. The ball bearing stack as defined in claim 1 , wherein the outer races of each of the more than one bearing being capable of limited swivelling movement about the common centre point to accommodate limited misalignment.

3. The ball bearing stack as defined in claim 1 , wherein a common inner sleeve is provided which serves as the inner ring for each of the bearings.

4. The ball bearing stack as defined in claim 1 , wherein the more than one bearing includes at least one bearing positioned near the common centre point which accommodates primarily radial loads, with bearings accommodating an increasing axial load component the farther they are spaced from the common centre point.

5. The ball bearing stack as defined in claim 1 , wherein the more than one bearing are symmetrically arranged with an equal number of bearings on either side of the common centre point.