System and method for assembling a spherical plain bearing

A spherical plain bearing and method of assembling the same is disclosed. The bearing has an outer ring having a bore, a concave surface, and at least one fracture. The bearing further includes an inner ring having a convex surface. The convex surface is in sliding disposition with the concave surface when the inner ring is disposed in the bore. The bearing has a groove in a face of the outer ring radially outside a first opening of the bore. The bearing further includes a band coupled to a portion of the outer ring defining the groove. The band retains the outer ring around the inner ring when the inner ring is disposed in the bore.

TECHNICAL FIELD

The present disclosure relates to spherical bearings. More particularly, the present disclosure relates to a spherical plain bearing in which a band is coupled to a portion of the bearing.

BACKGROUND

Spherical plain bearings generally have spherical contact surfaces that allow an inner ring to rotate with multiple degrees of freedom relative to an outer ring when the inner ring is disposed in a bore defined by the outer ring. This freedom facilitates a self-aligning ability of the bearing such that it can adjust to misalignment that may occur due to the application of loading forces, machining tolerances, welding distortions, or mounting distortions due to static and dynamic forces.

In some current designs, the outer ring of a bearing includes two or more sections separated by fractures that enable the outer ring to be positioned around the inner ring during assembly. This type of bearing is typically referred to as a fractured bearing. Fractured bearings are typically easier to assemble because it is easier to dispose the inner ring in the bore of the outer ring.

Current designs of fractured spherical plain bearings typically use steel snap rings, bands, or plastic tie wraps located on an outside surface of the outer ring to maintain the outer ring in position during, for example, shipping and installation. In some current designs, one or more grooves are included on the outside surface of the outer ring. The grooves typically serve to maintain the snap rings, bands, or plastic tie wraps in position on the outside surface of the bearing. These additional grooves act as stress risers thereby promoting bearing failure under impact loads.

SUMMARY OF THE INVENTION

According to aspects illustrated herein, there is provided a spherical plain bearing. The bearing has an outer ring having a bore, a concave surface, and at least one fracture. The bearing further includes an inner ring having a convex surface. The convex surface is in sliding disposition with the concave surface when the inner ring is disposed in the bore. The bearing has a groove located in a face defined by the outer ring. A band is at least partially positioned in the groove in a manner that releasably retains the band in the groove when installed in the groove. The band is operable to inhibit the fracture surface from opening up once the inner ring is installed.

According to other aspects illustrated herein, there is provided a spherical plain bearing. The bearing has an outer ring having a bore and a concave surface. The outer ring comprises two or more sections separated by fractures. The bearing further has an inner ring having a convex surface. The convex surface is in sliding disposition with the concave surface when the inner ring is disposed in the bore. The bearing has a groove located in a face defined by the outer ring. A band is at least partially positioned in the groove in a manner that releasably retains the band in the groove when installed in the groove. The band is operable to inhibit the fracture surfaces from opening up once the inner ring is installed.

According to other aspects illustrated herein, there is provided a spherical plain bearing. The bearing has an outer ring having a bore defined by a concave peripheral surface and an inner ring have a convex outer surface. The convex outer surface is in sliding disposition with the concave surface when the inner ring is disposed in the bore. A band is at least partially positioned in the groove in a manner that releasably retains the band in the groove when installed in the groove. The band is operable to retain a releasably retain a seal to the bearing, the seal for inhibiting ingress of particulate into an area between the concave surface of the outer ring and the convex surface of the inner ring.

According to other aspects illustrated herein, there is provided a method of assembling a spherical plain bearing. The method includes the step of providing an outer ring having a bore and defining a concave inner surface, the outer ring having two or more sections separated by fractures. The method further includes the step of providing an inner ring defining a convex outer surface, the convex outer surface in sliding disposition with the concave inner surface when the inner ring is disposed in the bore. The method further includes the step of providing a groove in a face of the outer ring. Positioning a band at least partially in the groove in a manner that releasably retains the band in the groove when installed in the groove. The band is operable to inhibit the fracture surfaces from opening up once the inner ring is installed.

DETAILED DESCRIPTION OF THE INVENTION

As shown inFIGS. 1-2B, a spherical plain bearing is generally identified by reference number10. The term “bearing” may be used in this description to refer to the spherical plain bearing10. The bearing10comprises an outer ring12and an inner ring14. The outer ring12has a bore22having a first opening23and a second opening25. While the illustrated embodiment shows an outer ring12having first and second bore openings23,25the invention is not limited in this regard. For example, the present invention may be employed with an outer ring having a single bore opening, or, for example, it may be employed with an outer ring having two or more bore openings having different diameters, for example, in an angular contact spherical plain bearing.

The outer ring12has a concave surface34. The inner ring14has a convex surface36. The convex surface36is in sliding disposition with the concave surface34when the inner ring14is disposed in the bore22of the outer ring12.

The outer ring12comprises two sections16,18. The first section16and the second section18each comprise approximately half of the outer ring12. The first section16and the second section18are separated by a first fracture line37and a second fracture line38. This may be referred to as a double fractured outer ring. During assembly of the bearing10, the first section16and the second section18are brought together around inner ring36at the first fracture line37and second fracture line38. This design facilitates assembly because the greatest outside diameter of the inner ring14is typically larger that the diameter of the first bore opening23or the second bore opening25. While the illustrated embodiment shows an outer ring12having first and second sections16,18the present invention is not limited in this regard. For example, the present invention may be employed with an outer ring comprising a single piece without any fractures, an outer ring comprising a single piece with a single fracture, or, with a outer ring comprising three or more sections.

The outer ring12has a first face20. A portion of the outer ring12defines a groove28is in the first face20of the outer ring12radially outside the first opening23of the bore22. In reference toFIG. 2A-2B, a portion of the outer ring12radially outside the groove28and extends radially inward defining a protrusion21. Although the present disclosure is shown with the protrusion, the disclosure is not limited in this regard. The first face20of the outer ring12, for example, may have a groove without a protrusion, or the outer ring may have a groove having multiple protrusions. The outer ring12further includes a counter bore26in the first face20of the outer ring12. Although the embodiment illustrated inFIGS. 1-2Bis shown with a counter bore26, the bearing of the present disclosure is not limited in this regard, and may be employed with an outer ring not having a counter bore.

As shown inFIG. 2B, a band30is coupled to the first face20of the outer ring12. The band30is ring shaped and has an outer portion31and an inner portion32. The band30may be constructed from any suitable material, for example, rubber, cloth, metal, plastic, or the like. The band30is coupled to the outer ring12at least in part by friction between the band30and the outer ring12. In addition, the outer portion31of the band30may exert a force on the portion of the outer ring12that defines the groove28, thereby coupling the band30to the outer ring12. It is noted that the description refers to the band as being coupled to the outer ring. This means that the band is fixed in relation to the outer ring. In some embodiments, the band is detachably coupled to the outer ring, meaning the band is fixed relative to the outer ring by some combination of friction and forces between the components, but without use of any other element. In some embodiments, the band is fixedly coupled to the outer ring, meaning that band is fixed relative to the outer ring by some additional element, other than friction and forces between the band and the outer ring. For example, the band is fixed relative to the outer ring by staking, welding, adhesive, or other known method. It should be understood that the term coupled, as used in this application, includes both detachably coupled and fixedly coupled.

The outer portion31of the band30is received in the groove28. The outer portion31is folded in the groove28. An outer edge of the outer portion31of the band30abuts the protrusion21. The folded portion of the band30may serve in part to detachably couple the band30to the portion of the outer ring12defining the groove28. Specifically, forces between the surface of the outer portion31of the band30and the portion of the outer ring12defining the groove28may serve in part to detachably couple the band30to the portion of the outer ring12defining the groove28The groove has a first groove portion formed in the first outer ring section and a second groove portion formed in the second outer ring section; while the band coupled to the groove has a first band portion extending circumferentially around the first ring section from the first fracture to the second fracture, and a second band portion extending circumferentially around the second ring section from the second fracture to the first fracture. The first band portion engages the first groove portion in a first friction fit and imparts a first force circumferentially around the first ring section directed radially inwardly. The second band portion engages the second groove portion in a second friction fit and imparts a second force circumferentially around the second ring section directed radially inwardly. The first force and the second force cooperate to urge the first outer ring section and the second outer ring section together and retain the first outer ring section and the second outer ring section around the inner ring when the inner ring is disposed in the bore. While the illustrated embodiment shows the outer portion31of the band30being detachably coupled to portion of the outer ring12defining the groove28, the present disclosure is not so limited. For example, the band30may be coupled by staking, welding, or adhesive.

Although not expressly disclosed in the figures, a second band may be detachably coupled to a second face of outer ring12. It should be understood that the second band may be coupled in a manner similar to the first band30or in a manner different that the first band30. By providing first and second bands on a spherical plain bearing having first and second bore openings, the retention forces created by the bands are typically symmetric, thus providing a more stable bearing arrangement for shipping and installation. The band30serves in part to retain the first section16and the second section18of the outer ring12around the inner ring14after the bearing10is assembled.

In reference toFIG. 2B, the band30may be used to couple a seal44to the bearing10. In the embodiment shown inFIG. 2B, the seal44is received in the counter bore26. The inner portion32of the band30extends into the counter bore26and, at least in part, couples the seal44to a portion of the outer ring12defining the counter bore26. Additionally, the inner portion32of the band30applies a force on the seal44such that the seal44is urged against the convex surface36of the inner ring14. In this manner, the seal44is positioned so as to inhibit ingress of particulate into an area between the concave surface34of the outer ring12and the convex surface36of the inner ring14.

The use of the band30provides for easier seal installation and provides improved seal retention by allowing full seal face engagement and radial retention. In the illustrated embodiment, the band30couples the seal44to the bearing10. The present disclosure is not limited in this regard. For example, various shaped seals and coupling methods may be used with the band in accordance with the present invention. Additionally, the outer ring may not include a counter bore and the seal may be coupled to the first face of the outer ring below the groove. In some embodiments, a seal is not included. It other embodiments, a seal is included, but the seal is not coupled to the bearing by any portion of the band.

The disclosed configuration provides for a maximum contact area between the contacting surfaces of the outer ring12and the inner ring14without interference from the retention band30. Also, existing outer ring widths are maintained by incorporating the counter bore26in the front face20to account for the width of the retention band30. Additionally, the incorporation of the retention band30into the groove28on the front face20of the outer ring12eliminates the need for snap ring grooves on the outside diameter of the bearing.

In reference toFIG. 3, a bearing100in accordance with one embodiment of the present invention is shown. The bearing100has an inner ring114having a convex surface136and an outer ring112having a concave surface134. The convex surface136is in sliding disposition with the concave surface134when the inner ring114is disposed in a bore of the outer ring112. The outer ring112has a first face120. A groove128is in the first face120of the outer ring112radially outside a first opening of the bore. The outer ring112further defines a counter bore126in the first face120of the outer ring112extending along at least a portion of the perimeter of the first opening. A band130is coupled to the front face120. The band130is ring shaped and has and outer edge131and an inner edge132. The band130serves to, at least in part, couple a seal144to the bearing110. The counter bore126defines a second groove129radially above the first opening of the bore and radially below the groove128. An outer portion145of the seal144is received in the second groove129.

A portion of a bearing200in accordance with one embodiment of the present invention is shown is shown inFIGS. 4-5. Attachment of a retention band230at the front face220of the outer ring212and the incorporation of the counter bore226provides for a substantially flush front (and back) face220of the bearing200. The embodiment shown inFIGS. 4-5does not include a seal member.

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 scope of the invention.