Patent Application
20170108042
The present invention relates to a bearing assembly, and is more particularly related to a stack bearing assembly.
Bearing assemblies are used in a variety of applications, including large-scale drilling applications. Drilling applications require support bearings, typically in the form of a stack bearing assembly. Stack bearing assemblies are comprised of a plurality of bearing assemblies, which are stacked adjacent to each other to methodically and consecutively distribute the loads experienced by stack bearing assembly among the individual bearings.
During drilling, pressurized medium is provided to a well to flush debris from the well. As the debris exits the well, the debris travels through the rolling surfaces of the stack bearing assembly which erodes and damages the bearing components. The debris lowers the life cycle of the bearing in comparison to other applications and requires the bearing components to be replaced more often than such other bearing applications. Replacement of the bearings is expensive and time consuming. The debris can also cause the bearing to be less efficient and can also cause premature component failure.
Known bearing balls for stack bearings used in drilling applications are formed from 100Cr6 martensitic bearing steel (S2 or SAE 52100). Bearing life is usually determined by failure of the bearing balls which are typically the first component to fail. It would be desirable to increase the bearing life in stack bearings to provide further resistance to the damage caused by the debris traveling through the bearing assembly.
A stack bearing assembly with stacked bearing rings and bearing balls located in races therein is provided. The bearing balls are formed from 100Cr6 steel that is carbonitrided. After carbonitriding, the bearing balls are polished. The carbonitrided and polished bearing balls are assembled in the races of the bearing rings to provide increased resistance to wear from the debris traveling through the bearing assembly in use, and increased toughness in order to withstand the wear caused by debris in a drilling rig.
A method of producing a stack bearing assembly is also provided, including: forming bearing balls from 100Cr6 steel, carbonitriding the bearing ball, polishing the carbonitrided bearing balls, and assembling the bearing balls between inner and outer races of at least one rolling bearing.
The foregoing Summary and the following detailed description will be better understood when read in conjunction with the appended drawings, which illustrate a preferred embodiment of the invention. In the drawings:
Certain terminology is used in the following description for convenience only and is not limiting. The words “front,” “rear,” “upper” and “lower” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from the parts referenced in the drawings. “Axially” refers to a direction along the axis of a shaft or rotating part. A reference to a list of items that are cited as “at least one of a, b, or c” (where a, b, and c represent the items being listed) means any single one of the items a, b, or c, or combinations thereof. The terminology includes the words specifically noted above, derivatives thereof and words of similar import.
The use of the stack bearing assembly 10 with rolling bearings 12a-e having 100Cr6 bearing grade steel bearing balls 18 that are carbonitrided provides for an estimated two-fold or more increase bearing life for the stack bearing assembly 10.
Having thus described the present invention in detail, it is to be appreciated and will be apparent to those skilled in the art that many physical changes, only a few of which are exemplified in the detailed description of the invention, could be made without altering the inventive concepts and principles embodied therein. It is also to be appreciated that numerous embodiments incorporating only part of the preferred embodiment are possible which do not alter, with respect to those parts, the inventive concepts and principles embodied therein. The present embodiment and optional configurations are therefore to be considered in all respects as exemplary and/or illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all alternate embodiments and changes to this embodiment which come within the meaning and range of equivalency of said claims are therefore to be embraced therein.
