Patent ID: 8467045

Claim:
A method of determining the contact angle of a ball bearing, the method comprising: providing a ball bearing having a central axis and including an outer ring, an inner ring spaced axially from the outer ring so as to define a gap, a retaining cage disposed generally between the outer and inner rings, and a plurality of balls circumferentially spaced by the retaining cage and radially interposed between the outer and inner rings, each ball having a diameter; providing optical detecting means configured to project radiation; rotating one of the inner and outer rings about the central axis while the other one of the inner and outer rings remains substantially stationary; detecting a number of revolutions about the axis of at least one of the balls, or the cage, or both by projecting radiation from the optical detecting means through the gap in the bearing such that the radiation is intercepted directly by the at least one of the balls, or the cage, or both; detecting a number of revolutions about the axis of the rotating one of the inner and outer rings; and determining the contact angle using the detected number of revolutions of the rotating one of the inner and outer rings, the detected number of revolutions of the at least one of the balls, or the cage, or both, the diameter of each ball, and a pitch diameter of the plurality of balls.