Bearing elements, bearing apparatuses including same, and related methods

#Conventional bearing apparatuses including bearing surfaces that move relative to one another are known in the art. For example, conventional, so-called “thrust bearings” and some embodiments of radial bearings include bearing surfaces that at least partially contact and move or slide relative to one another. Such bearing surfaces may include a superhard material for resisting wear during use of the bearing. In one example, diamond (e.g., polycrystalline diamond) may comprise at least one or both of the bearing surfaces.

#More particularly, one application for bearings is drilling equipment utilized in the subterranean drilling arts. Particularly, drilling motors and drill bits with moving members, such as roller cones have been utilized for drilling boreholes into a subterranean formation, especially for oil or gas exploration. In a typical downhole drilling motor, the motor is suspended at the lower end of a string of drill pipe comprising a series of pipe sections connected together at joints and supported from the surface. A rotary drill bit (e.g., a fixed cutter drill bit, roller cone drill bit, a reamer, etc.) may be supported below the drilling motor (via pipe sections, drill collars, or other structural members as known in the art) or may be directly connected to the downhole motor, if desired. Drilling fluid, which is commonly known as drilling mud, is circulated through the pipe string and the motor to generate torque within the motor for causing the rotary drill bit to rotate. Then, the drilling fluid is returned to the surface through the annular space between the drilled borehole and the drill string and may carry the cuttings of the subterranean formation to the surface.

#Further, as known in the art, mechanical systems may include radial bearings. For example, conventional downhole drilling may employ radial bearings. In one embodiment, an inner and outer race are each provided with a plurality of superhard bearing elements (e.g., polycrystalline diamond elements). The races are positioned adjacent one another so that the bearing surfaces of the bearing elements contact one another. As may be appreciated, geometry and configuration of the bearing elements of the races may be an important factor influencing the performance and life of such a bearing structure. Examples of conventional radial bearing apparatuses are disclosed by U.S. Pat. Nos. 4,662,348, 4,729,440, 4,738,322, 4,756,631, and 4,764,036, the disclosure of each of which is incorporated, in its entirety, by this reference.

#Further features of the subject matter of the instant disclosure, its nature, and various advantages will be more apparent from the following detailed description and the accompanying drawings, which illustrate various exemplary embodiments, are representations, and are not necessarily drawn to scale, wherein:

#FIG. 1 shows a perspective view of one embodiment of a bearing element according to the present invention;

#FIG. 2 shows a top elevation view of the bearing element shown in FIG. 1;

#The present invention relates generally to bearing apparatuses including bearing surfaces comprising superhard materials. “Superhard,” as used herein, refers to any material having a hardness that is at least equal to or exceeds a hardness of tungsten carbide (e.g., polycrystalline diamond, boron nitride, silicon carbide, mixtures of the foregoing, or any suitable material). For example, a polycrystalline diamond compact (PDC) is normally fabricated by placing a cemented carbide substrate into a container or cartridge with a layer of diamond crystals or grains positioned adjacent one surface of a substrate. A number of such cartridges may be typically loaded into an ultra-high pressure press. The substrates and adjacent diamond crystal layers are then sintered under ultra-high temperature and ultra-high pressure (“HPHT”) conditions. The ultra-high pressure and ultra-high temperature conditions cause the diamond crystals or grains to bond to one another to form polycrystalline diamond. In addition, as known in the art, a catalyst may be employed for facilitating formation of polycrystalline diamond. In one example, a so-called “solvent catalyst” may be employed for facilitating the formation of polycrystalline diamond. For example, cobalt, nickel, and iron are among examples of solvent catalysts for forming polycrystalline diamond. In one configuration, during sintering, solvent catalyst comprising the substrate body (e.g., cobalt from a cobalt-cemented tungsten carbide substrate) becomes liquid and sweeps from the region adjacent to the diamond powder and into the diamond grains. Of course, a solvent catalyst may be mixed with the diamond powder prior to sintering, if desired. Thus, diamond grains become mutually bonded to form a polycrystalline diamond table upon the substrate. A conventional process for forming polycrystalline diamond cutters is disclosed in U.S. Pat. No. 3,745,623 to Wentorf, Jr. et al., the disclosure of which is incorporated, in its entirety, by this reference. The solvent catalyst may remain in the polycrystalline diamond layer within the interstitial pores between the diamond grains or may be at least partially removed by leaching (i.e., exposing at least a portion of the diamond table to an acid) or by any suitable method. Optionally, another material may replace the solvent catalyst that has been at least partially removed from the polycrystalline diamond. In another embodiment, optionally, polycrystalline diamond may include nanodiamond (i.e., ultra-dispersed diamond), if desired. In another example, a silicon carbide and diamond composite material as disclosed in U.S. Pat. No. 7,060,641, the disclosure of which is incorporated herein, in its entirety, by this reference may comprise a bearing surface.

#In one embodiment, a bearing apparatus may include polycrystalline diamond inserts or compacts defining a plurality of surfaces that move relative to one another. Such bearing apparatuses may encompass so-called thrust bearings, radial bearings, or other bearing apparatuses including bearing surfaces that move in relation to one another, without limitation. More particularly, the present invention relates to a structure for supporting at least one bearing element including an arcuate bearing surface (e.g., convex, concave, substantially cylindrical, substantially spherical, etc.), wherein a bevel or chamfer is formed about at least a portion of a periphery of the bearing surface.

#One aspect of the present invention relates generally to bearing apparatuses including an inner race and an outer race wherein the inner race includes a plurality of bearing elements collectively defining a bearing surface and wherein the outer race includes a plurality of bearing elements collectively defining another bearing surface. Such bearing elements may comprise a superhard material, such as, for example, polycrystalline diamond. According to one aspect of the present invention, a bearing element may include a chamfer or other geometry that removes or diminishes a sharp edge or corner at a periphery of a bearing surface of a bearing element. Such a configuration may provide a relatively robust bearing element for use in a bearing apparatus.