FORMULAS
Edge margin is a calculated distance based on the relationship between the edge margin (y) and the groove depth (d). When y/d
3, the groove will withstand the maximum thrust load as
indicated in the Rotor Clip catalog specification page for that particular size and type
of retaining ring. Example: SH-50 external retaining ring installed on a cold-rolled steel shaft. The catalog specifications for this ring call; for a minimum edge margin of 0.048" and a groove depth of 0.016." Our formula is as follows:
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| Finite Element Analysis shows stress gradients for a retaining rings in an application with insufficient edge margin. When loaded, the high stress region extends over the entire groove wall to the end of the shaft (or housing) and the groove wall actually distorts.Under these conditions, the ring would buckle, possibly leading to catastrophic failure. |
If an application requires an edge margin less than the recommended specifications, it is necessary to calculate the thrust load (Pg)-capacity of the groove, to determine if the reduced margin is capable of handling the anticipated thrust load. The following formula applies (Note: see Correction Factors table for Gf value; Yield Strength of Groove Material for sy value; Edge Margin Graph for K1 value; Nomenclature Table for remaining catalog specifications):
