Flange piloted drawn inverted roller bearing

A roller bearing comprises a cylindrical inner race having axial ends folded over an outside surface thereof. A cylindrical roller cage, having a plurality of axially disposed roller pockets with roller retainer bars at radially outer edges thereof, is slid onto the folded ends of the inner race; and a plurality of cylindrical rollers is snap fitted into the roller pockets between the folded ends of the inner race. The roller cage pilots radially on the folded ends of the inner race, and the roller ends pilot axially against the folded ends of the roller cage.

BACKGROUND OF THE INVENTION
 This invention relates generally to roller bearings and more particularly
 to inverted bearings with roller retainers piloted on flanges of the inner
 race.
 Current inverted cylindrical roller bearings, having the rollers on the
 outside of the race, are made by forming a sleeve on a press to provide a
 lip at each axial end. The sleeve is heat treated (hardened and tempered),
 and an axially split roller cage, or retainer, is filled with rollers and
 wrapped around the sleeve. The cage edges are then joined to retain the
 roller complement on the sleeve.
 This process yields serviceable bearings, but it requires several
 non-value-added steps which drive up manufacturing costs and introduce
 risks which contribute nothing to the performance of the finished bearing.
 The roller retainer (cage), after assembly on the sleeve, requires welding
 or mechanical fastening. This presents an opportunity for misalignment of
 the edges of the retainer, distortion of the retainer and the roller
 pockets, and possible thermal damage to the sleeve and/or the rollers.
 These discrepant conditions must be corrected by rework which, if
 unsuccessful requires that the assembly be scrapped.
 The foregoing illustrates limitations known to exist in present inverted
 radial roller bearings. Thus, it would be advantageous to provide an
 alternative directed to overcoming one or more of the limitations set
 forth above. Accordingly, a suitable alternative is provided including
 features more fully disclosed hereinafter.
 SUMMARY OF THE INVENTION
 In one aspect of the present invention, this is accomplished by providing
 an inverted roller bearing comprising a cylindrical inner race having
 axial ends folded over an outside surface thereof; a cylindrical roller
 cage having a plurality of axially disposed roller pockets with roller
 retainer bars at radially outer edges thereof fitted over the folded ends
 of said inner race; and a plurality of cylindrical rollers snap fitted
 into said roller pockets between said folded ends of said inner race.
 The foregoing and other aspects will become apparent from the following
 detailed description of the invention when considered in conjunction with
 the accompanying drawings.

DETAILED DESCRIPTION
 FIGS. 1 and 2 show a typical inverted bearing "A" of the prior art. It has
 a sleeve or inner race 10 with a lip 20 formed at each axial end about its
 whole circumference. A roller cage or retainer 40 has roller pockets 42 in
 which a plurality of rollers 30 are rotatably trapped by retainer bars 44.
 The cage 40 is wrapped around the sleeve 10 between the lips 20 and joined
 by a weld 45, by mechanical means, or by other joining means. The cage 40
 is axially restrained by the lips 20 to guide the rollers 30 around the
 sleeve or race 10. During assembly of this bearing there is a chance to
 lose rollers 30 from the pockets 42 due to separation of the radially
 outer retainer bars 44 while wrapping the cage 40 around the sleeve 10. It
 is also possible to misalign the faying surfaces of the cage 40 when
 welding or joining the cage ends. Finally, there is a chance that
 mechanically joined edges may separate during shipping or after
 installation in the end product. In any case, the bearing must be reworked
 if possible, or it must be scrapped. Of course, in cases of failure of
 such joints after installation of the bearing, there may be severe damage
 to components other than the bearing.
 The inverted bearing of the invention avoids or minimizes many of the
 manufacturing difficulties and defects inherent in bearings of the prior
 art described above. The bearing "B" illustrated in FIGS. 3 and 4 shows
 the key features of the invention. It comprises an inner race 50 with
 folded back ends 60, a roller retainer or cage 70, and rollers 30 which
 are trapped in roller pockets 72 by retainer bars 74. The unique features
 of this invention are provided by the method of manufacturing. This method
 permits forming and assembly of the inverted bearing "B" of the invention
 while avoiding the risks described above for the inverted bearings "A" of
 the prior art.
 An inner race 50 is formed from a seamless cylindrical tube or sleeve. Its
 axial ends are folded back upon the outer surface of the race 50 to form a
 roller channel about the circumference thereof between the resulting
 flanges 60. A cylindrical roller retainer 70 has a plurality of roller
 pockets 72 with retainer bars 74 only on the outer edges of the pockets.
 This is, preferably made as a flat strip, with the roller pockets 72 and
 retainer bars 74 formed therein; rolled, welded or otherwise permanently
 joined to form a continuous cylindrical roller cage or retainer 70, and
 sized and trued on a mandrel, if necessary. It may also be made from a
 seamless cylindrical tube which is sized on a mandrel, if necessary, to
 provide a controlled inner diameter. The cage or retainer is fitted over
 the race 50 so that its ends pilot radially on the flanges 60. Rollers 30
 are then snapped into the roller pockets 72. After the rollers 30 are in
 place in the roller channel between the edges of the flanges 60, the
 retainer or cage 70 is axially located by axial piloting action of the
 ends of the rollers 30 on the edges of the flanges 60.
 Formation of the roller retainer as a continuous cylindrical body with no
 mechanical seam or joint provides assurance that the bearing rollers and
 retainer will not become separated from the inner race or misaligned in
 shipping and handling. The provision of the folded back flanges, together
 with the continuous cylindrical roller retainer, permits simplified
 assembly without further welding or forming operations on the components.