| 摘要 |
An earth boring drill bit having roller cutters which are rotatably supported on journals by bushings. At least one of the bushings is formed by a plurality of bushing segments which are positioned about a circular bearing surface having thrust shoulders at each end thereof. The roller cutter elements are assembled about the bushing segments in heated condition, by press-fitting to establish a firmly seated relationship between the cutter and bushing segments upon cooling of the cutter. The rotary cutter is then secured to the bushing segments by means of a locking element to prevent inadvertent disassembly during drilling operations. End portions of the bushing segments engage hardened bearing inserts of cutter support legs to minimize wear during drilling operations. A circular sealing element positioned about the bushing segments establishes sealing engagement with the cutter support legs to prevent ingress of contaminants and egress of lubricant during drilling activity.
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