Bearing and lubrication system for earth boring bit

摘要

Methods and apparatus for maintaining lubrication of rolling cone cutters mounted on journal pins. Embodiments comprise a rotating cone disposed on a journal pin and forming a journal gap there between. A cylindrical journal sleeve is disposed in the journal gap. The journal sleeve has a longitudinal gap forming opposing end portions, which are continuously contoured. A lubrication port is disposed in the journal pin and in fluid communication with a lubrication supply. The lubrication port has an outlet located in a recess in the journal gap. Each end of the recess comprises a transitioning surface extending between the bottom of the recess and the outer surface of the journal pin to prevent sharp transitions. In certain embodiments, the journal pin may comprise two or more lubrication ports, each located in a recess with transitioning surfaces.