CERAMIC ROLLING ELEMENT WITH SKELETAL STRUCTURE

Abstract

A bearing rolling element with a lattice internal structure provides several advantages over a solid bearing. It is lighter than a solid bearing, reducing centrifugal forces. For ceramic bearings, less material is required, and sintering times are reduced because bonding material can flow easily to near the surface. Elements with an internal lattice also offer advantages over hollow rolling elements. The shell can be thinner without sacrificing load capacity. The thinner shell reduces the time required for bonding material to be removed during sintering. The blank can be formed using various additive manufacturing processes.

Claims

1. A method of producing a rolling element for a bearing comprising: forming a hollow rolling element blank comprising ceramic and a bonding material by an additive manufacturing process; and evacuating the bonding material from the hollow rolling element blank.

2. The method of claim 1 wherein a thickness of the hollow rolling element blank is selected to carry a design load.

3. The method of claim 1 wherein the hollow rolling element blank comprises: an outer shell; an inner shell; and a thickness between the inner shell and the outer shell selected to carry a design load.

4. The method of claim 3 wherein the hollow rolling element blank further comprises a skeletal core.

5. The method of claim 3 wherein the outer shell and the inner shell are spherical.

6. The method of claim 5 wherein the hollow rolling element blank further comprises a skeletal core.

7. The method of claim 1 wherein the evacuating the bonding material comprises a sintering process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a cut-away view of a hollow ball rolling element.

[0010] FIG. 2 is a cut-away view of a partially hollow ball rolling element with a lattice core.

DETAILED DESCRIPTION

[0011] Embodiments of the present disclosure are described herein. It should be appreciated that like drawing numbers appearing in different drawing views identify identical, or functionally similar, structural elements. Also, it is to be understood that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.

[0012] The terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the following example methods, devices, and materials are now described.

[0013] Use of hollow or partially hollow rolling elements offers advantages in many applications regardless of material and geometric configurations.

[0014] FIG. 1 is a cut-away view illustrating a hollow ball rolling element 10. Rolling elements other than balls may also be hollow. The ball includes a shell 12 with an inner spherical surface 14 and an outer spherical surface 16. The shell must be sufficiently thick to carry the design load. Hollow ceramic rolling elements are particularly advantageous. For a given rolling element diameter, a hollow rolling element uses substantially less material, reducing both cost and mass. Furthermore, evacuating the bonding materials from the shell requires substantially less time than removing them from the core of a solid element.

[0015] FIG. 2 is a cut-away view illustrating a partially hollow ball rolling element 10′ with a skeletal core 18. The skeletal framework provides extra strength, increasing the load capacity or decreasing the required shell thickness for a given design load. The open space in the lattice permits the bonding material from the lattice material to move easily to the inner surface of the shell during the sintering process, such that sintering times are substantially reduced relative to a solid.

[0016] Conventional molding processes are unsuitable for fabricating the blanks for the balls of FIGS. 1 and 2. However, additive manufacturing processes (sometimes called 3D printing) are capable of producing these blanks.

[0017] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the disclosure that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.