The present invention is generally directed to an end cap with a retaining portion for a bearing and is more specifically directed to a light weight end cap having a retaining portion capable of removably securing the end cap to a bearing assembly and resisting inadvertent removal from the bearing.
Many types of bearings can be used to support radial, thrust, or combination radial and thrust loads. Such bearings include ball, roller, plain, journal and tapered roller types. To reduce friction, a lubricant such as a grease or oil can be introduced into the bearing.
Bearing performance can degrade, or severe and even catastrophic damage can occur, if insufficient lubricant is provided to the bearing. Where a bearing contains rolling elements, rotation of these rolling elements can act to pump lubricant out of the bearing. In addition, bearing performance can be detrimentally affected as a result of contamination of the lubricant and/or the introduction of foreign matter into the bearing. Seals have been used to help retain the lubricant within the bearing and to minimize contamination and foreign matter from entering therein. Such seals are typically made from a resiliently compliant material such as rubber, synthetic rubber or a composition thereof, such as Viton®.
A fitting, such as a grease fitting, can be positioned accordingly to provide a location for the introduction of the lubricant into the bearing.
According to a first aspect of the present invention, an end cap for a bearing includes a first body section which is substantially symmetric about a central axis of the end cap. The end cap has a first seating surface defining an opening extending through the first body section coaxially with the central axis. The end cap also includes a second body section extending away from the first seating surface and terminating at a second seating surface. The opening is operable to receive a portion of an inner member of the bearing. The first seating surface is operable to engage a portion of the inner member. The second seating surface is operable to slidingly engage a portion of an outer ring which is disposed around a portion of the inner member.
The end cap can be made from a resilient plastic, a resilient metal or a resilient composite material.
According to another aspect of the present invention, a bearing includes an outer ring having a substantially cylindrical internal bearing surface and an inner member having a substantially cylindrical external bearing surface. A portion of the inner member is coaxially disposed within the outer ring. The external bearing surface and the internal bearing surface cooperate to define an annular cavity therebetween. A plurality of rolling elements is disposed within the annular cavity. The rolling elements are in rolling engagement with the external bearing surface and the internal bearing surface. The inner member defines a recess for engaging a portion of an end cap, as described further below.
In addition, the bearing includes an end cap defined by a first body section which is substantially symmetric about a central axis of the end cap. The first body section also has a first seating surface which defines an opening extending through the first body section coaxially with the central axis. The end cap also defines a second body section extending away from the first seating surface and terminating at a second seating surface. A portion of the inner member is positioned in the opening with the first seating surface being seated in the recess of the inner member. The second seating surface engages a portion of the outer ring. The end cap extends between the inner member and the outer ring.
In one embodiment, the recess of the inner member defines a circumferential groove in which the first seating surface is disposed. The groove can be located on a portion of the inner member positioned outside of the outer ring.
In another embodiment, the outer ring defines a recess in which the second seating surface is sealingly engaged.
In addition, the first seating surface and the second seating surface can be substantially perpendicular to one another.
As shown in
The portion of the shaft 30 disposed in the bore of the inner ring 14 is substantially cylindrical. The inner ring 14 may be pressed, shrunk, or otherwise secured onto the shaft 30. The inner ring 14 and the portion of the shaft 30 therein cooperate to form an inner bearing structure of the shaft and bearing assembly 10.
The shaft 30 has a bore 52 that is formed, cut or otherwise disposed in a distal end 39 of the shaft. The bore 52 has a first portion 53 that is adjacent to the distal end 39 of the shaft 30 and that has a diameter d1. A second portion 55 of the bore 52 is adjacent to the terminal end 56 of the bore and has a diameter d2. The diameter d2 is larger than d1, such that a shoulder 54 is defined in the bore 52 between the first portion 53 and the second portion 55, as seen in
Referring to
The split ring 51 is configured to have, in a relaxed state, an outside diameter that exceeds the diameter d1 in the bore 52 and an inside diameter that does not exceed the diameter of the shank 46 (so that even in the relaxed state, the split ring 51 remains seated in the seating groove 59). In addition, the split ring 51 and the seating groove 59 are configured so that the split ring can be compressed to conform to a diameter dl. When the shank 46 is inserted into the shaft 30, the inner wall 63 of the first portion 53 of the bore 52 applies a force F (indicated in
Preferably, the shank 46 releasably engages the seating portion so that the end cap 12 can be removed from the shaft and bearing assembly 10 and may then be replaced, e.g., to temporarily expose the end of the shaft 30 and the outboard end 36 of the bearing 72 for inspection, maintenance or any other purpose. For example, the split ring 51 contacts the shoulder 54 at a point near its circumferential perimeter, i.e., at a radial distance Dc from the axis A to a point on the split ring beyond the greatest diameter DR of the split ring measured parallel to the axis A, as seen in
The body portion 40 of the end cap 12 has a disc-like configuration which extends from the central engaging portion (i.e., from the shank 46) radially outward, across the annular cavity to an outer engagement portion 42 disposed thereon which sealingly engages the mating surface 34 of the outer ring 16. Thus, the end cap 12 provides a barrier to the introduction of contamination and foreign matter into the annular cavity 22.
Although the detent mechanism is shown as a split ring 51 fitted into a seating groove 59, the present invention is not limited in this regard, as other suitable detent mechanisms can be used to mechanically couple the end cap 12 to the shaft and bearing assembly 10, including but not limited to ball and spring mechanisms, protrusions or resilient fingers projecting outwardly from the outer surface 50, or a combination thereof. Furthermore, the seat on the shaft and bearing assembly 10 that engages the detent member may be a detent-receiving groove of any form suitable to the detent member. Moreover, although a detent mechanism is shown and described, the present invention is not limited in this regard, as it will be apparent to one of ordinary skill in the art that the engagement portion on the end cap 12 that mechanically couples the end cap to the shaft and bearing assembly 10 may comprise a seating portion for a detent on the shaft and bearing assembly.
While the shank 46 has been described above as being substantially cylindrical, the present invention is not limited in this regard as the shank can be of any suitable cross-sectional shape including but not limited to hexagonal, square and star-shaped cross sections. The end cap 12 can be manufactured from a resilient plastic material such as polyurethane and the split ring 51 can be manufactured from spring steel, however, the invention is not limited in this regard as other materials may be used for the end cap 12, including but not limited to metals, composite materials and combinations thereof, and/or other materials may be used for the split spring 51 or other detents, including but not limited to other metals, composite materials and combinations thereof.
While the bearing 72 is shown with two sets of rolling elements 28 separated by a shoulder 24 that projects from the inner ring 14, this is not a limitation on the invention, and various other configurations of bearings, rolling elements, etc. are known in the art and, in view of the disclosure herein, all such bearings and shaft and bearing assemblies can employ an end cap as described herein.
The end cap 112 shown in
The end cap 212 shown in
The end cap 312 shown in
The shaft and bearing assembly 410 shown in
The detent-receiving groove 462 is formed, cut or otherwise disposed in the end 436 and defines a shoulder 464. The shoulder 464 is defined by a transition between a first section 466 of the detent-receiving groove 462 having an inside diameter d3 and a second section 468 of the detent-receiving groove 462 having an increased diameter d4 adjacent the terminal end 470 of the bore, wherein d4 is greater than d3.
The inner ring 414 extends axially towards the end of the shaft 430 than does the outer ring 416, so that part of the substantially cylindrical external bearing surface 418 extends beyond the annular cavity 422.
The end cap 412 on the shaft and bearing assembly 410 has a body portion 440 but no shaft portion. The end cap 412 is manufactured from a resilient plastic material such as polyurethane. The body portion 440 has an annular configuration having an inner portion 413a which provides the central engagement portion of the end cap 412. The annular inner portion 413a mechanically engages a groove (unnumbered) on the inner ring 414, the groove providing a seat for retaining the end cap 412 on the shaft and bearing assembly 410.
The end cap 412 includes a lip 415 (
Referring to
The shaft 430 includes flow paths 480 and a port 482 for conveying a lubricant to the annular cavity 422 via an inner ring flow path aperture 480a. In operation, the lubricant can by supplied to the bearing assembly 410 without removing the end cap 412.
While the end cap 412 is shown engaging inner ring 414, the present invention is not limited in this regard as an inside circumferential surface may alternatively engage a portion of a shaft in the bearing. For example, in the shaft and bearing assembly 410′ shown in
The end cap 512 shown in
In another embodiment, the inner bearing structure is integral with the shaft, as seen in the shaft and bearing assembly 610 of
As illustrated in
A recessed mating surface 734, for example, a groove, is formed into a transverse end, for example an end face, of the outer ring 716 for receiving a portion of an end cap 710, as described below. An end portion 793 of the shaft 730 extends out of the outer ring 716. A portion of the shaft 730 adjacent to the end 793 defines an external surface 794. Another recessed mating surface 747, for example, a groove, is formed into the external surface 794 of the shaft 730.
The shaft and bearing assembly 710 also includes an end cap 712 which is removably disposed thereon. The end cap 712 defines a first body portion 740 that has a central opening 741 defined by a generally annular first seating surface 745 that is seated in the recessed mating surface 747 in the shaft 730. The end cap 712 includes a second body portion 739 which extends away from the first seating surface 745 and terminates at a substantially circular second seating surface 742. The second seating surface 742 sealingly and slidingly engages the recessed mating surface 734 on the end of the outer ring 716. The end cap 712 is illustrated having a bend 790 which defines the junction of the first body portion 740 and the second body portion 739. The bend 790 is configured to position the first seating surface 745 and the second seating surface 742 substantially perpendicular to one another.
While the central opening 741 is shown and described as being defined by a generally annular first seating surface 745, the present invention is not limited in this regard, as other shapes and configurations may be employed including but not limited to rectangular and hexagonal shapes. Although the second seating surface 742 is shown and described as being substantially circular, the present invention is not limited in this regard as other shapes and configurations may be employed including but not limited to hexagonal and elliptical shapes.
The end cap 712 can be manufactured from a resilient plastic material such as polyurethane, however, the invention is not limited in this regard as other materials may be used, including but not limited to metals, composite materials and combinations thereof.
The opening 741 is operable to receive an end of the shaft 730. In addition, during installation, the end cap 712 is elastically deformed by expanding the opening 741 onto the shaft 730. When the end cap 712 is installed on the shaft 730 with the second seating surface 745 removably secured and seated in the groove 747, the end cap returns to an un-deformed state.
Although the present invention has been disclosed and described with reference to certain embodiments thereof, it should be noted that other variations and modifications may be made, and it is intended that the following claims cover the variations and modifications within the true spirit of the invention.
This application is a divisional of U.S. patent application Ser. No. 12/062,841, filed Apr. 4, 2008 and which claims the benefit of U.S. provisional application No. 60/921,949 filed Apr. 4, 2007, both of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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60921949 | Apr 2007 | US |
Number | Date | Country | |
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Parent | 12062841 | Apr 2008 | US |
Child | 13290342 | US |