Bearing system for an articulating motor device

A bearing system for a rotating vertical shaft, the bearing system comprising:

• a first ball bearing, having a first pitch diameter and a first axial stiffness, the first ball bearing having a first inner ring disposed in a first outer ring and a first plurality of balls rollingly positioned between the first inner ring and the first outer ring so that the first plurality of balls rollingly engage a first exterior raceway of the first inner ring and a first interior raceway of the first outer ring at respective first axial centerlines of the first exterior raceway and the first interior raceway;
• a second ball bearing having a second pitch diameter and a second axial stiffness, the second ball bearing having a second inner ring disposed in a second outer ring, and a counterbore bore positioned in one of the second inner ring and the second outer ring;
• a second plurality of balls rollingly positioned between the second inner ring and the second outer ring so that the second plurality of balls rollingly engage a second exterior raceway of the second inner ring and a second interior raceway of the second outer ring at an angle offset from second axial centerlines of the second exterior raceway and the second interior raceway;
• the first inner ring and the second inner ring being coaxial, secured to one another and rotatable together;
• the first pitch diameter being at least 1.5 times greater than the second pitch diameter;
• and
• the bearing system having an axial stiffness ratio defined by the first axial stiffness divided by the second axial stiffness, wherein the magnitude of the axial stiffness ratio is based on an axial preload force applied to the second outer ring such that an operating torque of the bearing system is within a predetermined range at temperatures from minus 40 degrees Celsius to positive 85 degrees Celsius;
• wherein the second outer ring includes a circumferentially extending seal groove, and further comprising:
• a first seal having a sealing portion, a retaining shield, and a base portion, the base portion disposed in the seal groove such that the base portion frictionally engages the seal groove;
• wherein the sealing portion includes a neck portion extending from the base portion terminating at a tip portion, the tip portion slidingly engaging the second ball bearing, and
• wherein the second ball bearing further comprises a circumferentially extending groove and a snap wire is disposed in the groove, in slidable contact with the first seal.