| 摘要 |
An improved apparatus and method for rotatably mounting and retaining a rock bit roller cone on a journal of a drill bit is disclosed. The bit body has at least one depending leg with an outer free end and an inner end continuous with the remainder of the bit body, and the cone surrounds the leg adjacent the outer end, forming an annular space between the leg and the cone. At least two retention bearing sleeves are disposed in the space: a first fixed to the leg and rotatable relative to the cone; and a second, disposed longitudinally inwardly of the first, fixed to the cone and rotatable relative to the leg. The retention bearing sleeves cooperate to prevent relative movement of the second sleeve longitudinally past the first.
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