STAMPED ROLLER CLUTCH CAGE WITH INTEGRAL SNAP RING

Abstract: A one-piece metal cage (11) for a roller clutch (10) formed from a flat stamping (12) to provide a flat annular side plate (13) and a side ring (18) having a wavy form spaced from the side plate by a plurality of crossbars (15) extending parallel to the axis of the cage. The crests (19) of the wavy side ring (18) extend farther outward radially than the side plate (13) to snap into an annular groove (33) in the outer race (29) to positively retain the cage between the races (27,29).

Description: The present invention relates to overrunning clutches and more specifically to a roller clutch cage. In conventional overrunning clutches, a pair of concentrically arranged inner and outer races define an annular space therebetween housing a cage with openings to receive suitable rollers or sprags which are spring-loaded to a position prepared for engagement. Either a metal ribbon energizing spring is utilized for sprags or accordion or folding springs are used for clutch rollers with one end of each spring engaging the adjacent roller and the opposite spring end adapted to hook over a crossbar in the cage and retain the spring in operative position. Either the outer race or the inner race surface is provided with a series of circumferentially arranged camming surfaces or recesses that cooperate with the clutch rollers to provide a wedging action in one direction of rotation. Often, the cage includes radial projections extending into the recesses to provide rotational stability of the clutch cage relative to the races. However, the cage is still free to shift axially between the races unless means are provided to retain the cage in operative position and prevent axial movement thereof. To positively position the cage, one or more retaining rings, snap rings, or spacing rings are generally used, received in grooves in the races to prevent unwanted axial cage movement. The present invention overcomes this problem in a simple one-piece cage. GB-A-2 176 257 discloses an overrunning clutch in accordance with the prior art portions of claims 1 and 3. The present invention, as characterised in claims 1 and 3, used the resilient wavy form of the side disc or ring to provide tabs at the crests or valleys of the wavy form to snap into a groove provided in one of the races. While DE-A-2 348 733 and FR-A-2 385 947 disclose cages axially retained between races by tabs extending into a groove in one of the races, they do not provide the one-piece roller cage design including integral means to prevent undesirable and/or unwanted axial movement of the cage relative to and between the inner and outer races with these integral means being readily sprung into place engaging the groove. While in the later illustrated embodiment the side ring has a wavy form with circumferentially spaced crests that extend radially higher than the remainder of the cage, which crests are received in an annular groove in the outer race to hold the cage in position, in an alternative embodiment, the valleys of the wavy form are inwardly to snap into a groove formed in the inner race. The invention will be further illustrated, with reference to the accompanying drawings, in which:- Figure 1 is a side elevational view of a roller clutch assembly embodying the present invention. Figure 2 is a partial enlarged side elevational view of the assembly of Figure 1. Figure 3 is a partial cross-sectional exploded view of the clutch races and cage before assembly. Figure 4 is a cross-sectional view taken on the line 4-4 of Figure 2 showing the cage assembled. Figure 5 is a partial elevational view of the metal stamping which forms the one-piece clutch cage. Referring more particularly to the disclosure in the drawings wherein is shown an illustrative embodiment of the present invention, Figures 1 and 2 disclose a roller clutch assembly 10 having a one-piece, seamless clutch cage 11 formed from a one-piece stamping 12 shown in Figure 5. Considering the stamping, it consists of an annular side plate 13 with crossbars 15 and a side disc 18; the side plate having a plurality of projections 14, the shape of which correspond to the inclined ramps or cams 32 of the outer clutch race 29 and which can be introduced into these ramps 32. The number of projections 14 may correspond to the number of ramps or the projections may be circumferentially spaced to be received in alternate or otherwise spaced circumferentially as desired. The crossbars 15 are integral with the side plate at their ends 16 and their opposite ends 17 are integral with the side ring or disc 18. The disc 18 has a wavy form having relatively sharp or rounded crests 19 and valleys 21. Also as seen in Figure 5, additional secondary crossbars 22 may be formed integral with and positioned at the top part of the side plate 13 to provide additional support for the clutch rollers. An illustrative method of shaping the stamped member 12 to form the cage 11 involves bending the side plate 13 upwardly about the ends 16 of crossbars 15 and bending the side disc 18 downwardly about the ends 17 of the cross bars. Both the side plate 13 and side disc 18 remain substantially flat, however, the wavy form of the side disc is substantially expanded to spread out the wavy form as seen in Figures 1 and 2 to have smoother rounded crests 25 and flattened valleys 26; the valleys 26 lying closely adjacent the surface 28 of the inner race 27 of the roller clutch assembly 10. The crossbars 15 extend parallel to each other and to the axis of the cage 11 and, if utilized, the secondary crossbars 22 are bent such that they lie parallel to and extend in the same direction as crossbars 15. The sequence of operations forming the cage may vary or other forming methods may be utilized. The clutch assembly 10 includes an inner race 27 having the cylindrical surface 28 and an outer race 29 having an inner surface 31 with a plurality of circumferentially spaced inclined ramps or cams 32 adapted to receive the projections 14 on the side plate 13. Also formed in the inner surface 31 is an annular groove 33 cooperating with the cage disc peaks or crests 25. As seen in Figures 3 and 4, the crests 25 form tabs 34 on the side disc 18 that extend radially outwardly beyond the outer edge 35 of the side plate 13. In view of the inherent flexibility of the cage 11, the cage will slightly deform when inserted between the inner and outer races 27 and 29, respectively, to allow the tabs 34 to contract and then snap into the groove 33 in the outer race to retain the cage axially in position without the necessity of extra retaining rings. A clutch roller 36 is received in an opening between crossbars 15 to move in the inclined ramp or cam 32 in a wedging action, and a folding or accordion spring has one end 38 terminating in a concave surface engaging a roller 36 and the opposite end 39 is formed with a hook portion to be bent around a crossbar 15 to retain the spring in operative position. Thus, the spring 37 acts to resiliently bias the roller 36 into wedging engagement with the inner and outer races when the outer race rotates clockwise as seen in Figure 2. When the outer race rotates counterclockwise, the clutch will overrun and the rollers ride up on the ramps 32. When assembled, the cage will be positively retained to prevent undesirable axial movement relative to the races. In the alternative, if the clutch were internally cammed on the inner race, then the valleys 26 of the side disc or tabs added thereto, would project radially inwardly to extend into a groove formed in the surface 28 of the inner race 27. The axial holding force in either arrangement can be increased or decreased by increasing or decreasing the number of tabs allowed to overhang the outer diameter or underhang the inner diameter of the cage.

Claims: 1. An overrunning clutch (10) having inner (27) and outer (29) concentric races receiving a one-piece, seamless metallic cage (11) housing rollers (36) and folding springs (37) therefor, wherein said cage includes an annular side plate (13) and a spaced parallel side disc (18) joined by a plurality of crossbars (15) extending parallel to the cage axis, the side disc having a wavy form with crests (19) and valleys (21), characterised in that one of said races (29) has an annular groove (33), and in that tabs (34), formed by the crests (19) of the wavy form of said side disc (18), extend radially into the groove (33) to retain the cage axially between said races, the flexibility of said cage (11) allowing for partial deformation so that the tabs (34), which extend in a radial plane beyond the periphery of said side plate (13), can snap into the groove (33). 2. An overrunning clutch according to claim 1, wherein the groove (33) is provided in the outer race (29) and the tabs (34) extend radially outwardly beyond the outer periphery of the side plate (13). 3. An overrunning clutch (10) having inner (27) and outer (29) concentric races receiving a one-piece, seamless metallic cage (11) housing rollers (36) and folding springs (37) therefor, wherein said cage includes an annular side plate (13) and a spaced parallel side disc (18) joined by a plurality of cross bars (15) extending parallel to the cage axis, the side of the disc having a wavy form with crests (19) and valleys (21), characterised in that the inner race (27) has an annular groove, and in that tabs formed by the valleys (21) of the wavy form of the side disc (18) extend radially into the groove to retain the cage axially between the races, the flexibility of said cage (11) allowing for partial deformation so that the tabs, which extend in a radial plane inwardly beyond the inner periphery of the side plate (13), can snap into the groove in the inner race. 4. An overrunning clutch as claimed in any preceding claim, wherein a plurality of secondary cross bars (22) extend from said side plate (13) parallel to said first-mentioned cross bars (15).

Inventors: GROH, DAVID MICHAEL
Applicants: BORG-WARNER AUTOMOTIVE TRANSMISSION AND ENGINE COMPONENTS CORPORATION
Application year: 1989
Main classification: F16D41
IPC codes: F16D41