Cam Follower Bearings
Author - Sam Houston Regional Manager SA/NT
BSC have supplied cam followers (also known as track roller bearings) to Australian industry for over 50 years. As is the case with most of our products, technology is not standing still.
BSC’s supply partner the Schaeffler Group (INA/FAG), is a world leading manufacturer of this range and continue to engineer design improvements that enhance performance and maintenance considerations that benefit our customers.
Cam followers are rolling bearings with certain modifications which allow their outer rings to travel along a flat or curved counter raceway. They have been used in many industrial designs for more than half a century.
Cam followers or track rollers can be split into two groups:
- Yoke type
- Stud type
This allows flexibility of choice depending on design requirements.
The most prominent distinction between a standard roller bearing and a cam follower is the execution of the outer ring. Cam followers feature an outer ring which has an enlarged cross section compared to standard bearings. This allows the outer ring to cope with increased bending stresses and associated deformation of the outer ring when the cam follower is running on straight or curved tracks.
The deformation results in a reduced contact zone between rolling elements and raceways. This is taken into account in load ratings stated in respective catalogues. (values Crw and C0rw).
Another important feature is the profiled outer diameter of the outer ring. It reduces the extent of edge loading when cam followers are not perfectly aligned with the mating straight or curved track. Industry standard has been for many years to apply a profile radius of approx. 500 mm.
Misalignment between cam follower and track.
Stress reduction with profiled outer ring.
Latest X-life technology from the Schaeffler Group (INA/FAG) reduces acting stress even more. An optimised profile has been made available for various series of cam followers.
At first glance, the benefit may be reduced fatigue and wear on the cam follower only. However, the mating track will also be subjected to lower stresses and less wear. Particularly long tracks, as well as elaborate cam profiles, can be very costly to replace or to refurbish. Thus considerable cost savings during the machine life are achieved when utilising cam followers with optimised profile.
Stud type cam followers feature hexagonal sockets (except sizes 16 and 19, which feature slots) to accommodate allen keys during the mounting of the nut. Stud type cam followers are generally supplied with a nut suiting the threaded stud end.
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|Relubrication choices of a stud type cam follower.|
Inside the hexagonal sockets are lubrication bores for re-lubrication.
They can be fitted with grease nipples, closing plugs or central lubrication adapters.
One grease nipple, one closing plug and one nut is normally supplied together with the stud type cam follower.
|Misaligned cam follower positioning and stud type cam follower with eccentric locking collar.|
When groups of cam followers are to be used in line to provide support, stud type cam followers with eccentric locking collar are recommended.
The eccentric locking collar provides the capability to align all cam followers in such way that they all sit on the track without clearance.
These product feature the letter E in the product designation (e.g. KRE19PP).
The variety of features introduced above leads to a number of different designs of cam followers. Underneath can be seen different series, distinguished between yoke and stud type as well as between ball and roller type.
Yoke type cam followers
Stud type cam followers
Cam followers are versatile machine elements which have proven their capabilities for many decades. The large variety available allows optimal selection for the application concerned.
BSC primarily stock and provide design recommendations on INA brand of Stud and Yoke type cam followers as technology leaders in this series of bearings.
BSC also supply McGill, Smith and RBC range of imperial series cam and roller followers.
For further information and technical support on this range of bearings contact your local BSCC outlet.
Reference: Mr Andreas Piper – Schaeffler Group Engineering Manager/Quality Manager