Page 40 of Cam Followers by RBC Bearings

technical data cam followers yoke and track rollers introduction to cam follower technology safety precaution in rare cases a bearing failure may cause great mechanical damage or even lead to personal injury to help prevent such losses you may contact rbc s engineering staff to review your application details the engineering staff s review will assist you in identifying potential problem areas and suggest modifications to improve bearing performance in your application the engineering staff at rbc has many years of experience with a large variety of applications and operating conditions if you have a safety related application and would like an evaluation by rbc s engineering department please submit your application details in confidence the outer ring around the point of contact the effects are outer ring deformation with reversed bending stresses in dynamic applications a reduced load zone and a higher maximum roller load see fig 1 to keep deformation to a minimum the outer ring of a cam follower must have a considerably heavier cross section than a standard bearing this requirement conflicts with the desire for maximum dynamic bearing capacity which needs as large a roller diameter as possible rbc cam followers and yoke rollers provide an optimum compromise between outer ring strength and theoretical bearing capacity 2 capacity and load limits evaluation of the expected service life and limit loads of cam followers is more complex than with housed bearings in addition to the static and dynamic capacity of the rolling elements outer ring deformation track capacity and cam follower stud bending stress must be considered in yoke rollers the pin shear stress must be considered rbc lists the static bearing capacity for reference purposes only typically the maximum allowable load is a function of the maximum permissible bending stress of the stud or the outer ring for best results the operating loads should not exceed the lower of track capacity or 50 of the dynamic capacity 2.1 capacity of rolling element bearing equations for static and dynamic capacities of roller bearings are given in ansi/abma standard 11 the more recent revisions leave it up to the manufacturer to introduce factors which account for internal design features and operating conditions for cam followers and yoke rollers rbc has chosen to apply a conservative rating system so a direct comparison with capacity figures of competitive products may not be possible 2.2 track capacity 1 difference from standard bearings the outer rings of regular ball and roller bearings are typically mounted in rigid housings providing support around the entire circumference individual roller forces are transmitted through the outer ring directly into the housing with no major deformations by contrast cam followers and yoke rollers are supported at a single point on their circumference individual roller forces produce bending moments on load zone deformed outer ring deformed outer ring rigidly supported outer ring contact stress profile rigidly supported outer ring load zone rigidly supported outer ring contact stress profile deformed outer ring load zone maximum contact stress fig 1 40 track capacity is that load which a track subject to a uniform contact stress can withstand without excessive plastic deformation it is directly related to track hardness the published track capacity is based on a hardness of hrc 40 for other track hardness values the track capacity must be modified with factors from table 1.

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