BACKGROUND

Wear-resistant, polycrystalline diamond compacts (“PDCs”) are utilized in a variety of mechanical applications, including bearing apparatuses. For example, the bearing apparatuses may be thrust-bearing apparatuses or radial bearing apparatuses.

Bearing elements included in such bearing apparatuses may comprise a PDC typically including a superhard polycrystalline diamond (“PCD”) layer commonly known as a diamond table. The diamond table is formed and bonded to a substrate using a high-pressure/high-temperature (“HPHT”) process. The PDC bearing element may be brazed into a preformed pocket, socket, or other receptacle formed in a bearing support ring.

Despite the availability of a number of different bearing apparatuses including such PDCs, manufacturers and users of bearing apparatuses continue to seek bearing apparatuses that exhibit improved performance characteristics, lower cost, or both.

SUMMARY

Embodiments of the invention relate to bearing apparatuses including a bearing stator assembly and a bearing rotor assembly. The bearing stator assembly and bearing rotor assembly each include a support ring and one or more superhard bearing elements, with each of the one or more superhard bearing elements including a respective bearing surface. The bearing surfaces of the bearing stator assembly and bearing rotor assembly are generally opposed to one another. The bearing apparatus is specifically configured so that the bearing surface(s) of the rotor and the bearing surface(s) of the stator include different materials. For example, the bearing surface(s) of one of the rotor or stator may include diamond (e.g., polycrystalline diamond), while the bearing surface(s) of the other of the rotor or stator may not include diamond, but may include a non-diamond superhard material (e.g., silicon carbide) or another type of material such as a diamond-silicon carbide composite.

Such configurations advantageously provide bearing apparatuses that may be manufactured at lower cost, as compared to configurations that employ PCD bearing surfaces on both generally opposed bearing surfaces. In addition to reduced initial cost, additional benefits of such a configuration may include that the rotor or stator that does not include diamond may wear preferentially, so as to fail or otherwise wear out before the other of the rotor or stator that does include diamond. The non-diamond rotor or stator may be replaced at significantly lower cost than replacement of the entire bearing apparatus (i.e., both rotor and stator) where both rotor and stator bearing surfaces comprise diamond. Failure of the non-diamond bearing surface(s) may advantageously not result in damage to downstream equipment such as valves or other components that would be damaged by failure of a diamond bearing surface.

In addition, diamond bearing surfaces exhibit significantly higher thermal conduction than other superhard materials, such as silicon carbide. Because of this difference, use of silicon carbide or similar non-diamond superhard materials for both stator and rotor bearing surfaces may not allow sufficient heat transfer away from the bearing surfaces for practical use in some applications. Use of a diamond rotor or stator with a silicon carbide or other non-diamond superhard material for the other of the rotor or stator may provide improved heat transfer away from the silicon carbide or other non-diamond superhard material bearing surface. Thus, while use of non-diamond superhard material for both stator and rotor bearing surfaces may not be practical in some applications, use of a diamond and non-diamond bearing surfaces for the stator and rotor may overcome such thermal management problems.

In an embodiment, a bearing apparatus may include a thrust-bearing assembly and a radial bearing assembly in which the bearing surfaces of both the stator and rotor of the thrust-bearing assembly include diamond, and the bearing surfaces of both the stator and rotor of the radial bearing assembly do not include diamond, but comprise another superhard material (e.g., silicon carbide). For example, such a thrust-bearing assembly may include a thrust-bearing stator and a thrust-bearing rotor, each including a stator support ring and one or more superhard bearing element(s). The superhard stator and rotor thrust-bearing element(s) each include respective superhard thrust-bearing surface(s) that are generally opposed to one another. The radial bearing assembly may include a radial bearing stator and a radial bearing rotor, each including a support ring and one or more superhard bearing element(s). The superhard stator and rotor radial bearing elements each include respective superhard radial bearing surfaces that are substantially opposed to one another. The superhard stator and rotor thrust-bearing surfaces may include diamond, while the superhard stator and rotor radial bearing surfaces may not include diamond, but include another superhard material (e.g., silicon carbide).

Embodiments of the invention also relate to methods of use in which a bearing structure that does not include diamond is used with a generally oppositely disposed other bearing structure that does include diamond, so that the bearing structure that does not include diamond wears preferentially, and is replaced after a period of use. Thus a single bearing structure (e.g., a rotor) that does include diamond may be employed sequentially with a plurality of corresponding non-diamond bearing structures (e.g., stators) that wear preferentially, and are replaced before the diamond bearing structure needs to be replaced.

For example, a bearing assembly may be provided, as described above, in which either the rotor or stator includes diamond, while the other of the rotor or stator does not include diamond, but includes another superhard material (e.g., silicon carbide). After a period of use during which the non-diamond bearing rotor or stator may wear preferentially, the non-diamond bearing rotor or stator may be replaced.

Features from any of the disclosed embodiments may be used in combination with one another, without limitation. In addition, other features and advantages of the present disclosure will become apparent to those of ordinary skill in the art through consideration of the following detailed description and the accompanying drawings.

