| 摘要 |
<p>A downhole expandable roller bearing apparatus (2) is described. The apparatus (2) comprises a plurality of roller assemblies comprising at least one roller (12) rotatably mounted between pistons (14). A retaining member such as a spline bar (26) is removably mounted in a keyway formed in the body (4). Each piston (14) comprises an aperture (30) through which the spline bar (26) projects in both the inwardly retracted and outwardly deployed positions of the pistons (14).</p> |
