Axial Play and Pre-Load in TRB
Axial Play and Pre-Load in TRB
(OP)
How to calculate the axial play and pre-load in the taperRoller Bearing?
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Axial Play and Pre-Load in TRB
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RE: Axial Play and Pre-Load in TRB
RE: Axial Play and Pre-Load in TRB
If you have a high speed application, in many cases it is impossible to run a simple taper roller with a fixed preload - the bearing will burn up. In general, to actually calculate the minimum acceptable clearance or how much preload you can tolerate from first principles is extremely difficult - it requires a coupled transient thermal- mechanical FEA analysis. So you are usually left with rules of thumb and manufacturer's recommendations, tempered by your own and others experience. Poplawski Associates have recently developed a computer program which runs in conjunction with Ansys, to enable detailed calculations to be carried out, but it's a complicated exercise.
RE: Axial Play and Pre-Load in TRB
RE: Axial Play and Pre-Load in TRB
There are several approaches that come to mind for finding the ideal clearance :
1. Ask the bearing manufacturer (probably Timken). Sometimes they will run a detailed computer analysis for you - it depends how important you are to them as a customer as to how much detail and time they will spend, and also what your relationship is with the local representative, and how motivated he happens to be. If they just give you a general recommendation, it is unlikely to be optimum, and they will probably suggest you try it and revise if necessary using approach 2 below in any case.
2. Trial and error. Start off with a small clearance, do heat checks, and try reducing and increasing the clearance, performing more heat checks etc. If you are using grease lube, you have to be careful to let the grease "channel" before taking the temperature readings seriously.
3. Use a program called "Shaberth", if you can find it. This is an old mainframe era program for thermally optimizing bearing preload and is very hard to use by modern standards, although there is a DOS version.
4. Use Poplawski's new Cobra-AHS program (if it's ready) in conjunction with ANSYS. He will also consult in tricky cases. See http://www.bearingspecialists.com/software.asp
RE: Axial Play and Pre-Load in TRB
to start out with .0002 preload and run the bearing
and keep increasing the preload until you start
experiencing too much heat generation. A lot of the
theoretical calculation considers speed as well
as the loads. Too much preload ends up in overloading
the bearing and an early failure. Whoever designed
the bearing application must have had some spec to
work with. More is not always better.
RE: Axial Play and Pre-Load in TRB