摘要 |
A rotary bearing includes concentric radially spaced-apart inner, intermediate and outer rings whose opposing surfaces define inner and outer ball tracks. An inner array of balls roll along the inner track and an outer array of balls roll along the outer track and a viscous lubricant is present between the rings. When the inner and outer rings are angularly reciprocated relative to one another, the intermediate ring is moved intermittently in a selected direction about the rotation axis so that the balls recirculate about the axis and redistribute lubricant along the tracks. In a preferred embodiment, the relative angular excursion of the inner and outer rings is increased periodically beyond a selected maximum angle to effect the advancement of the intermediate ring using the lubricant as a ratcheting mechanism. |