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Cam follower vs Needle/Ball Bearing 1
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MikeHalloran
Mechanical
I have worked on a product that used both instrument ball bearings and similar sized needle bearings as cam followers.
The followers drove ceramic valves or piston pumps, moving salt water at low velocities and relatively low pressures.
Pressure transducers allowed one to watch the needle rollers and the bearing balls pass through the loaded area of the race circumference. That was not the intent of the design; it was an accidental aberration due to the flexure of the races under modest loads in a loading situation for which they were not intended.
Ball bearings, and needle bearings in particular, are intended for installation in a bore that is stiff enough to properly support them. Neither is suitable for use as a cam follower unless you are prepared to tolerate trajectory errors that are not present in the cam itself.
Look closely at cam follower rollers. The races are _much_ thicker than a ball bearing race, and much, much thicker than a needle bearing shell.
If you need a cam follower, use a cam follower roller.
Crowned or not crowned is a property of the OD of the follower's outer race. It has nothing to do with the bearing inside, except to the extent that it affects the distribution of cam load along the axis of the bearing.
Mike Halloran
Pembroke Pines, FL, USA
The followers drove ceramic valves or piston pumps, moving salt water at low velocities and relatively low pressures.
Pressure transducers allowed one to watch the needle rollers and the bearing balls pass through the loaded area of the race circumference. That was not the intent of the design; it was an accidental aberration due to the flexure of the races under modest loads in a loading situation for which they were not intended.
Ball bearings, and needle bearings in particular, are intended for installation in a bore that is stiff enough to properly support them. Neither is suitable for use as a cam follower unless you are prepared to tolerate trajectory errors that are not present in the cam itself.
Look closely at cam follower rollers. The races are _much_ thicker than a ball bearing race, and much, much thicker than a needle bearing shell.
If you need a cam follower, use a cam follower roller.
Crowned or not crowned is a property of the OD of the follower's outer race. It has nothing to do with the bearing inside, except to the extent that it affects the distribution of cam load along the axis of the bearing.
Mike Halloran
Pembroke Pines, FL, USA
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