| 摘要 |
A rotary drill bit comprising at least one rotatably carried roller cutter (12) is provided with a seal (18), which separates the bearing spaces of a forward bearing (14) and a rear roller bearing (16). For purposes of ensuring efficient cleaning of the bearing space of the rear bearing (16) flushing fluid is supplied to the forward portion of the race thereof. For purposes of further decreasing the risk that impurities enter into the bearing system through a gap (20) between the roller cutter (12) and the bit body (10) a seal (29) having check valve function may be mounted in the gap (20). |
