| 摘要 |
A roller on reamer's rollers are rotatably mounted on shafts whose ends are supported by blocks inserted in the reamer body. One end of each shaft is welded, pinned, or otherwise nonrotatably anchored to its mounting block. Each block makes an interference fit with the body socket in which it is disposed. The blocks are stepped or tapered for quick release. Access openings to the backs of the blocks facilitates knockout. Knockout of the stepped blocks is achieved by wedge means. Drilling mud may have access to contacting surfaces of rollers and shafts to lubricate same. Protective seal means may be provided between each roller and shaft at the upper ends thereof so that the mud must flow upwardly to reach the space between shaft and roller and dense solids will be excluded by gravity. Grease lubrication may be provided, e.g. in conjunction with roller shafts mounted in stepped blocks, the rollers being sealed to the shafts at both ends. Tapered blocks facilitate sealing as required for air lubrication through the shafts. With mud and air lubrication, axial loads in the rollers may be taken by the ends of the rollers bearing on the blocks. With protected mud lubrication and grease lubrication, thrust may be taken by thrust bearing surfaces provided within the protected or sealed zone, e.g. by a flange on each shaft engaging an internal groove formed by a two piece roller, or a ball lock between opposed annular grooves in shaft and roller.
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