End cap for bearing housing units

Abstract: A rolling element bearing is mounted in the bore of a housing (10), and a hollow end cap (40) is mounted over the bearing. Circumferentially spaced grooves (34, 36) in the bore extend axially partially through the housing from one axial end to facilitate insertion of the bearing. The end cap (40) has a closed wall (44) at one axial end and resilient projections (48, 50) extend axially from its open end, firmly engaging the housing grooves (34, 36). A strap holder (74), integral with the end cap, may be provided between the two resilient projections, extending radially outwardly along the axial end of the housing (10) and axially along a housing outer surface (72) and has an opening for mounting a grease fitting (70). An integral flexible strap (82) extends from the strap holder and has a cover (84) to enclose the grease fitting.

Description: This invention relates generally to antifriction bearing assemblies. More particularly, this invention is a bearing assembly with an end cap to be used if the bearing housing does not have a grease fitting and a one-piece conbination end cap and grease fitting cover to be used if the bearing has a grease fitting. Previous end cap utilisation has been primarily to exclude contamination from bearings used in very dirty environments. With the institution of more stringent safety regulations, end caps are being used with increasing frequency to provide protection from rotating shafts protruding from the bore of housed bearing units. Such bearing housings may be provided with grease fittings to provide relubrication capability. In that instance, it is advantageous to have a protective cover installed over the grease fitting to protect it from mechanical damage and contamination. US-A-4 342 490 describes an end cap for a bearing providing a protective function and also preventing contamination from entering the bearing. The end cap is provided with lipped lugs that fit into an annular groove on the outside surface of a bearing outer ring. However, the bearing assembly requires extensive machining operations to provide the annular groove on the bearing outer ring. SE-8-306645 (equivalent to GB-A-1205886 and FR-A-1562 729) discloses features in accordance with the preamble of claim 1. According to the present invention, there is provided a bearing assembly comprising a housing having an axially extending bore with circumferentially spaced grooves extending axially partially through the housing from one axial end of the housing, the grooves being to facilitate the insertion of a rolling element bearing into the housing, a said bearing mounted in the bore and having inner and outer bearing rings with rolling elements; and a hollow end cap having a closed wall at one axial end; wherein the end cap is provided with resilient projections extending axially from a peripheral edge of the open end of the end cap and firmly engaging the housing grooves; characterised in that the housing has a grease fitting on an outer surface, there being a strap holder integral with the end cap, located circumferentially between the projections and extending from the cap with a first portion radially outwardly along the axial end of the housing having the grooves and with a second portion joined to the first portion axially along the housing outer surface, the strap holder having an opening for the grease fitting. For a better understanding of the invention and to show how the same may be carried into effect, reference will not be made, by way of example to the accompanying drawings, in which:- Fig. 1 is a front view illustrating an embodiment of a bearing assembly, with an end cap removed; Fig. 2 is sectional view of the bearing assembly of Fig. 1, taken along line 2--2; Fig. 3 is a sectional view illustrating an embodiment of an end cap and a portion of the bearing housing of Fig. 1, as indicated by the line 3--3; Fig. 4 is a sectional view similar to Fig. 3 illustrating a further embodiment of an end cap and a portion of a corresponding bearing housing; Fig. 5 is a sectional view similar to Fig. 3 illustrating a still further embodiment of an end cap and a portion of a corresponding bearing housing. The end caps according to Fig 3 to 5 are not covered by the claims. Fig. 6 is a perspective view illustrating an embodiment of a combined end cap and grease fitting cover according to the invention; Fig. 7 is a perspective view of the embodiment of the combined end cap and grease fitting cover of Fig. 6 mounted on a bearing housing; Fig. 8 is a perspective view illustrating a second embodiment of the combined end cap and grease fitting cover according to the invention; and Fig. 9 is a perspective view illustrating a third embodiment of the combined end cap and grease fitting cover according to the invention. Referring to the drawings, Figures 1 and 2 illustrate a bearing assembly having a housing 10 with base 12 providing means (shown in Figure 3) for attaching the bearing assembly to a supporting surface. In this embodiment, the housing 10 is of pillow block configuration and includes a ball bearing having an outer bearing ring 14, an inner bearing ring 16 and balls 18 in rolling contact with an outer raceway 20 and an inner raceway 22 on the respective bearing rings. Alternatively, other housing configurations and other types of bearings may be used. The housing 10 has an annular concave spherical inside surface 24 slidably retaining an annular convex spherical outside surface 26 of the outer bearing ring 14 to provide self-alignment. Optional seals 28 and 30 may be mounted at the axial ends of the outer ring 14. In order to facilitate the insertion of the bearing into the housing 10, the bore 32 of the housing 10 has two diametrically-opposed grooves 34 and 36 known as loading slots. The grooves.34 and 36 extend axially partially through the housing from an axial end surface 38. Referring to Figure 3, an end cap 40 is a one-piece hollow, generally frustum-like configuration pressed out of steel or other metal or formed from polymer material. For example, polypropylene or low-modulus nylon may be used. The end cap 40 has a frustoconical wall 42 merging with a closed end wall 44 at its narrowest end. The opposite end of the end cap 40 is open and defined by a peripheral edge 46. A pair of diametrically-opposed resilient projections 48 and 50 extend axially from the peripheral edge 46 and include fingers 52 and 54, respectively, at their axial ends. The fingers 52 and 54 extend radially outwardly and axially toward the closed end wall 44. In the embodiment of Figure 3, the housing 10 has a channel 56 each located near the axially inner end of the grooves 34 and 36, as shown. Each channel 56 extends radially outwardly and axially outwardly into the housing 10. The projections 48 and 50 are resiliently deformed radially inwardly as they are inserted into the grooves 34 and 36 and snap radially outwardly into the channels 56 firmly to fix end cap 40 over the protruding end of a shaft 55, shown in Figure 1. To release the end cap 40, pressure can be applied manually to the conical wall 42 to deform the end cap such that the projections 48 and 50 move radially inwardly and release the fingers 52 and 54 from channels 56. In the embodiment of Figure 4, the projections 48 and 50 are replaced by resilient projections 58 and 60, each having a plurality of barbs or vanes extending axially and radially outwardly in their unbiased positions, before the projections 58 and 60 are inserted into respective housing grooves 34a and 36a. When inserted, the barbs or vanes are deflected radially inwardly by the grooves 34a and 36a and biased against the grooves 34a and 36a such that the end cap is retained by friction. The surface of the grooves 34a and 36a may be rough, for example as with cast iron, to enhance this frictional retention. In the embodiment of Figure 5, the housing grooves 34b and groove 36b have respective centrally located concave recesses 62. Resilient projections 64 extend axially from the peripheral edge 46 and have respective convex protuberances 66 extending radially outwardly such that each convex protuberance 66 is biased into engagement with concave recesses 62 to provide a snap-together installation. The end cap can be removed by axially withdrawing it from the housing 10 such that the convex protuberances 66 are forced radially inwardly by engagement with the concave recesses 62. Many bearing assemblies have a grease fitting, such as a grease fitting 70 shown in Figure 1, for example, extending radially outwardly from an outer surface 72 of the housing 10. Referring to Figure 6, a one-piece combination end cap and a grease fitting cover according to the invention is shown for use with bearing assemblies having a grease fitting. The structure of the end cap portion of the embodiment shown is the same as the structure of the end cap embodiment of Figure 3; however, if desired, the structures of the end cap embodiments of Figure 4 or Figure 5 may be used. As shown in Figures 6 and 7, a resilient strap holder 74 is spaced circumferentially between the resilient projections 48 and 50. The strap holder 74 is integral with the end cap conical wall 42 at a location spaced a small distance from the peripheral edge 46. A portion 76 of the strap holder 74 extends radially outwardly along the axial end 38 of the housing 10 and a portion 78 of the strap holder 74 extends along the housing outer surface 72. The lengths of the portions 76 and 78 depend on the particular housing and bearing configurations with which the combination end cap and grease fitting cover is used. The portion 78 of the strap holder 74 is provided with a circular opening 80 and an integral resilient strap 82 extending from the portion 78. The outer end of the strap 82 has a flat, circular support 84 supporting a hollow generally cup-shaped protrusion 86. The resilient strap 82 may be bent such that the cup-shaped protrusion 86 covers and provides an interference fit with the grease fitting 70. The strap holder 74 is held firmly in place by inserting the grease fitting 70 through the opening 80 and turning a hexagonal nut portion 88 to thread the grease fitting 70 into the housing 10 (or flange type housing 10a) against the portion 78. In the embodiment of Figure 8, the opening in the portion 78 of the resilient strap holder 74 is a full-sided slot 90, and the resilient strap 82 extends from an axial free edge 92 of the portion 78. In the embodiment of Figure 9, the opening in the portion 78 of the resilient strap holder 74 is an open slot 94 that extends into the resilient strap holder portion 78 from a radically extending side surface 96. The open slot 94 is positioned under the grease fitting 70 by rotating the combination end cap and grease fitting cover with respect to the housing 10 (or 10a). It will be appreciated that the end cap may be used with pillow block or flange type housings, either with or without grease fittings. Instead of using a housing with a spherical inside surface and a bearing with a spherical outside surface, as illustrated, a housing and bearing with non-spherical surfaces, such as straight cylindrical surfaces, may also be used.

Claims: A bearing assembly comprising a housing (10) having an axially extending bore with circumferentially spaced grooves (34, 36) extending axially partially through the housing from one axial end of the housing, the grooves being to facilitate the insertion of a rolling element bearing into the housing, a said bearing mounted in the bore and having inner and outer bearing rings (14, 16) with rolling elements (18); and a hollow end cap (40) having a closed wall (44) at one axial end; wherein the end cap (40) is provided with resilient projections (48, 50) extending axially from a peripheral edge (56) of the open end of the end cap and firmly engaging the housing grooves; characterised in that the housing (10) has a grease fitting (70) on an outer surface (72), there being a strap holder (74) integral with the end cap (40), located circumferentially between the projections (48, 50) and extending from the cap with a first portion (76) radially outwardly along the axial end of the housing (10) having the grooves (34, 36) and with a second portion (78) joined to the first portion (76) axially along the housing outer surface (72), the strap holder (74) having an opening (80) for the grease fitting (70). A bearing assembly according to claim 1, wherein the housing (10) has a channel (56) located within each of the grooves (34, 36), extending radially outwardly and axially outwardly into the housing, each projection (48, 50) having a finger (52,54) at its axial end extending radially outwardly and axially toward the end cap closed wall (44) and fitting into the respective channel (56). A bearing assembly according to claim 1, wherein each of the grooves (34a, 34b) of the housing have a concave recess (62) extending radially outwardly into the housing, and each of the projections (64) have a convex protuberance (66) extending radially outwardly to engage the respective concave recess (62). A bearing assembly according to claim 1, 2 or 3, wherein the grooves (34, 36) in the housing (10) are two in number, diametrically opposed from each other, and wherein the end cap projections (48, 50) are two in number, each projection firmly engaging a corresponding housing groove (34,36). A bearing assembly according to any one of the preceding claims, wherein the end cap (40) is a one-piece component. A bearing assembly according to any one of the preceding claims wherein each projection extends axially and radially outwardly in an unbiased condition and can be compressed radially inwardly when inserted into the respective groove (34,36) of the housing. A bearing assembly according to any one of the preceding claims, wherein the opening in the strap holder (74) is a full-sided elongated slot (90). A bearing assembly according to any one of the preceding claims wherein the opening in the strap holder extends into the second axially extending portion (78) of the strap holder from a radially extending side (96) of the strap holder. A bearing assembly according to any one of the preceding claims, comprising a flexible strap (82) integral with the strap holder, extending from the strap holder and having a hollow protusion (86) to enclose the grease fitting (70).

Inventors: WASKIEWICZ WALTER P, WASKIEWICZ, WALTER P.
Applicants: TORRINGTON CO, THE TORRINGTON COMPANY
Application year: 1997
Main classification: F16C35
IPC codes: F16C41, F16C35, F16C33