CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Patent

Application No. 62/653,282, filed April 5, 2018, the entire contents of which are incorporated by reference herein.

BACKGROUND

[0002] The present invention relates to bearings, and more specifically to rolling element bearings in which multiple rows of rolling elements are provided, along with separate, axially-adjacent races.

SUMMARY

[0003] The present invention provides a unitized multi-row rolling element bearing that can be packaged in an assembled state and installed without re-assembly or adjustment of the bearing setting. Multiple axially-adjacent races of the bearing are clamped together with at least one clamping element that forms part of the bearing assembly.

[0004] In one embodiment, the invention provides a bearing assembly including first and second axially adjacent bearing rings and first and second pluralities of rolling elements supported for rolling respectively by the first and second bearing rings. A retainer is configured to permanently and rigidly secure the first and second bearing rings together axially to unitize the bearing assembly and fix the bearing setting.

[0005] In another embodiment the invention provides a method of assembling a multi row roller bearing having a predefined angular contact of multiple rows or rolling elements, a multi-row bearing ring on a first radial side of the rolling elements, and separate single-row bearing rings on a second radial side of the rolling elements. A retainer is installed to the separate single-row bearing rings to permanently clamp them together, thus fixing a bearing setting. The roller bearing is installed with the fixed bearing setting into a machine and the machine is operated without adjusting the bearing setting. [0006] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Fig. 1 is a sectional view of a bearing assembly according to one embodiment of the present disclosure, shown in an exemplary installation.

[0008] Fig. 2 is a sectional view of a bearing assembly according to another embodiment of the present disclosure, shown in an exemplary installation.

[0009] Fig. 3 is a schematic illustration of positive end play in a tapered roller bearing. DETAILED DESCRIPTION

[0010] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

[0011] Fig. 1 illustrates a bearing assembly 20 for installation between two components, allowing rotation about a central axis A therebetween. The bearing assembly 20 is illustrated as rotatably supporting a shaft 22 with a gear 24 with respect to a housing 26 (e.g., a differential gear and housing), although this represents only one non-limiting example. The bearing assembly 20 is a multi-row rolling element bearing including multiple axially-spaced rows of rolling elements 28. The rolling elements 28 are retained between multiple inner races or rings 30A, 30B on a radially interior side and at least one outer race or ring 32 on a radially outer side. The illustrated bearing assembly 20 is a tapered roller bearing having separate rows of tapered rolling elements 28 that roll along paths offset by an angle a from the central axis A. The inner rings 30A, 30B are thus implemented as“cones”, each one forming a corresponding inner raceway 34, and the outer ring 32 is implemented as a dual “cup” that forms two outer raceways 36. In other embodiments, the bearing assembly 20 is a multi-row bearing having rolling elements of an alternate type (e.g., cylindrical, ball, or spherical rolling elements). Further, it is particularly noted that the multi-row bearings need not be limited to two rows of rolling elements. For example, another set of inner rings may be positioned axially adjacent the illustrated set of inner rings 30A, 30B to support two additional rows of rolling elements, along with another outer ring. This is not separately illustrated, but will be understood as an extension of the illustrated construction (e.g., duplicating of the parts already illustrated). In the illustrated embodiment, a cage 38 is provided to maintain the relative spacing between the rolling elements 28. A seal or seal assembly 40 is also provided between the outer ring 32 and an outer end of at least one of the inner rings 30A, 30B (e.g., left side of Fig. 1). The bearing assembly 20 may be retained relative to the supported components (e.g., housing 26 and shaft 22) by various means, including for example, retaining rings or clips. As shown, the outer ring 32 is axially retained with respect to the housing 26 with an outer retaining ring 42o and the inner rings 30A, 30B are axially retained with respect to the shaft 22 with an inner retaining ring 42i.

[0012] In addition to the above noted components that render the bearing assembly 20 as a functional unit, the bearing assembly 20 further includes a retainer 44. The retainer 44 is illustrated as a hollow cylindrical sleeve that forms an inner ring retainer operable to clamp the inner rings 30A, 30B together after assembly with the rolling elements 28 and the outer ring 32, and is maintained as part of the bearing assembly 20 through installation and operation. The retainer 44 has an inner surface 46 defining an inner diameter sized and configured to receive and support the shaft 22 along the outer surface 48 thereof. The retainer 44 is generally cylindrical and tubular to conform in shape to the cylindrical inner surfaces, or bores 56, of the inner rings 30A, 30B, and the retainer 44 is dimensioned to provide a tight fit between the shaft 22 and the inner rings 30A, 30B so that the retainer 44 effectively operates as an integral part with the inner rings 30A, 30B. In fact, the retainer 44 resides in an interstitial radial position between the inner rings 30A, 30B and the shaft 22, such that the retainer inner surface 46 defines the interior of the bearing assembly 20 rather than the inner rings 30A, 30B. The axial length L44 of the retainer 44 can be longer than the combined axial length L30 of the inner rings 30A, 30B. If not longer than the combined axial length L30 of the inner rings 30A, 30B, the retainer 44 can have an axial length L44 that is over 50 percent or at least 75 percent of the combined axial length L30 of the inner rings 30A, 30B. The retainer 44 extends axially to, and in some cases beyond, the respective outermost axial ends of the separate rows of rolling elements 28. If the bearing assembly 20 includes more than just two inner rings 30A, 30B (e.g., the addition of third and fourth inner rings), all the inner rings may be clamped together by the retainer 44. [0013] The retainer 44 has a first end 44A and a second end 44B, each of which forms a lip or flange extending radially (i.e., radially outward) to wrap around and engage the axial end faces of the corresponding inner rings 30A, 30B. However, at the time of assembly with the inner rings 30A, 3 OB, the retainer 44 may only have the lip or flange formed at the first end 44A. Subsequent to sliding the retainer 44 through the inner rings 30A, 30B, the second end 44B is plastically deformed (e.g., by roll forming) to form the lip or flange at the second end 44B. Although formation of a continuous lip or flange about the entire circumference is envisioned in some embodiments, other embodiments can include die forming, pressing with a punch tool, or staking the retainer 44 at multiple discrete circumferential locations, separately or simultaneously (e.g., with a multi-point punch tool). With its permanent deformation, the retainer 44 can immovably fix the relative positions of the inner rings 30A, 30B, which may be in direct contact with each other at their inner axial ends. If not in direct contact, the inner rings 30A, 30B may be separated by an incompressible spacer. The retainer 44 can be made of steel, or other suitable metals or metal alloys. The bearing assembly 20, without the retainer 44 is inherently non-unitized, meaning that the outer ring 32 can move relative to the inner rings 30A, 30B and the rolling elements 28.

[0014] In general, the amount of end play (axial clearance) or preload (axial interference) in a bearing assembly is referred to as the“setting,” see Fig. 3. Prior to installation, the bearing’s initial setting or“bench” end play may be a positive value indicating a certain amount of axial clearance (and thus, also radial clearance) between the rolling elements and their corresponding races. Once installed, the bearing’s setting may be referred to as the “mounted” setting as some amount of elastic deformation may occur upon pressing the bearing with an interference fit into its installation location. Finally, at running temperature, the bearing will exhibit a different setting, referred to as“operating” setting. Bearings are thus engineered for a particular bearing setting that will result in good operational loading and bearing life. Often, in the case of a multi-row tapered rolling element bearing like that of Fig. 1, the bench setting provides positive end play, and even after assembly (e.g., with a shaft and housing) axial compression must be applied to squeeze the inner rings 30A, 30B together to obtain a desired mounted setting (e.g., reducing or eliminating the positive end play). This is done by retaining the bearing assembly 20 with a nut threaded onto the shaft 22 so that the nut can be torqued to increase the clamping force axially compressing the inner rings 30A, 30B together. For this purpose, it has been known to position a compressible spacer in the stack-up of components compressed by the nut (e.g., between the two inner rings). Thus, the installation procedure necessarily involves actively measuring and/or setting the bearings appropriate mounted setting value by torqueing the nut to a prescribed value (or measuring via indirect means, such as torque required to rotate the shaft) after the bearing is installed.

[0015] In the case of the bearing assembly 20, the installation of the retainer 44 to clamp the inner rings 30A, 30B sets the bearing setting by clamping the inner rings 30A, 30B together as a rigid unit. Positive end play in the bearing assembly 20 can be eliminated at the time of manufacture of the bearing assembly with the retainer 44, prior to installation. Once installed in place as shown in Fig. 1, the bearing retention structure may be devoid of any adjustable means for applying variable axial load to the bearing assembly 20 for obtaining the desired bearing setting, since it is effectively preset at the time of manufacture. Although it is noted that pressing the shaft 22 into the retainer 44 and pressing the outer ring 32 into the housing 26 can have a predetermined effect on the mounted setting, the mounted setting does not change from the bench setting in other embodiments. It is particularly noted that, in some constructions, the bearing assembly 20 is retained in place with an external axial clearance (e.g., between the bearing assembly 20 and the inner retaining ring 42i) since there is not an inherent need for preloaded or tightened elements compressed against the bearing assembly 20. This is not to be confused with axial clearance within the bearing assembly 20. Because the bearing assembly 20 does not rely on external axially applied force from the installation in order to remove the positive end play and achieve the desired setting, the bearing assembly 20 can be externally retained with a small amount of axial clearance without introducing internal end play. Such an example is illustrated by the broken line alternate position of the gear 24 in Fig. 1.

[0016] It is noted that the retainer 44 of Fig. 1 is shown to include ends 44A, 44B that extend past the axial end faces of the inner rings 30A, 30B so that the end 44A is interposed between the end face of the second inner ring 30B and the gear 22 and the end 44B is interposed between the end face of the first inner ring 30A and the inner retaining ring 42i. However, one or both ends 44 A, 44B may be recessed into the respective inner rings 30A, 30B. An example of this type of arrangement is shown in the alternate bearing assembly 120 of Fig. 2, including notches or recesses 150 in both inner rings 130A, 130B. As shown, the retainer ends 144A, 144B are fully recessed so as to not protrude beyond the total axial length of the two inner rings 130A, 130B. The recesses 150 are provided at the respective axial end faces, although at least one of the recesses 150 may be inset from the axial end face in other constructions. In another modification from the embodiment of Fig. 1, the retainer 144 illustrated at the top of Fig. 2 is a discontinuous retainer, for example one of a plurality of retainers 144 at separate circumferential locations. As such, a plurality of separate bore grooves 154 are cut into the inner rings 130A, 130B, along the inner bores 56 thereof, to accommodate the retainers 144. The retainers 144 can be shaped as round or flat-sided pins or stakes. Alternately, the retainers 144 can be shaped as semi-cylindrical sleeve segments. Regardless of shape, the assembly method for installing the retainers 144 can be similar to that described above with respect to the sleeve retainer 44. That is, the second ends 144B can each be plastically deformed (e.g., in a die, pressed with a punch tool, or staked) to rigidly clamp the inner rings 130A, 130B together, without clearance. In some exemplary methods, the retainers 144 are simultaneously pressed, e.g., with a multi-point punch tool. As shown, the outer surface 48 of the shaft 22 contacts the inner surfaces 146 of the retainers 144 at some circumferential locations, and contacts the inner rings 130A, 130B directly at other circumferential locations. In a further modification, contact with the outer shaft surface 48 may be made exclusively by the inner rings 130A, 130B. That is, the grooves 154 may be spaced radially outward of the inner bore formed by the inner rings 130A, 130B.

[0017] As shown in both Figs. 1 and 2, each bearing assembly 20, 120 is unitized for storage, transportation, handling, and installation exclusively by the retainers 44, 144. In the case of Fig. 1, a singular retainer 44 unitizes the bearing assembly 20. Although several retainers 144 are used in the bearing assembly 120 so as to not concentrate the clamping at a single circumferential location, each one of the retainers 144 effectively unitizes the bearing assembly 120. In other words, each one of the retainers 144 is a singular element that rigidly clamps the inner rings 130A, 130B together and becomes an integral component of the bearing assembly 120.

[0018] Although the illustrated embodiments are focused on bearings having separate inner rings and a dual cup outer ring, such that the retainers 44, 144 securely clamp the inner rings together, it is also envisioned to reverse the arrangement such that the retainers 44, 144 are utilized to securely clamp multiple separate outer rings together. For example, in a double inner roller bearing, a single dual-row inner ring is provided and the directions of the two angles a are reverse from that shown in Figs. 1 and 2, so that the dashed lines of the two separate roller assembly paths converge toward the center of the bearing. Such a bearing assembly will have separate outer ring“cups” forming outer raceways for the separate rolling element groups. With appropriate adaptations to the disclosure above, one or more retainers 44 according to the description above of the retainers 44, 144 can be used to unitize and clamp the two (or more) outer bearing rings together. In such an embodiment, the retainer 44 may be positioned radially between an outer surface of the outer rings and the bore in the housing 26. In embodiments where the retainer 44 is not a full annular ring, the retainer(s) 44 may or may not contact the housing 26, and the outer rings may contact the housing 26 directly, at least at some locations.