Wheel friction
Wheel friction
(OP)
Hi,
I'm calculating bearing loads for a turntable with wheels running on circular rails. The wheels are positioned vertically and they are not driven.
Does anyone know how to calculate axial bearing load?
I'm calculating bearing loads for a turntable with wheels running on circular rails. The wheels are positioned vertically and they are not driven.
Does anyone know how to calculate axial bearing load?





RE: Wheel friction
Any chance of a sketch or drawing? I am a little confused as your title talks about friction forces, but your main question relate's to axial loads on bearings.
Here is a site that deals with rolling and sliding friction if that helps:-
ht
desertfox
RE: Wheel friction
In real life the turntable is a circular steel structure with 60 wheels evenly spaced on two concentric rails.
Hope it helps explaining my problem.
RE: Wheel friction
Well that helps for starters well rolling friction coefficients for the wheel and track can be obtained from that site link I gave you earlier.
The axial force at the bearing are you looking for the centrifugal force due to the rotation of the turntable?
If so go to this link and scroll down till you come to
rotary motion.
http://
desertfox
RE: Wheel friction
W * mu * sin(a)
mu is the coefficient of adhesion between wheel and rail (this is not the coefficient of friction).
a is the slip angle of the wheel.
a will be small, so axial load will be small.
RE: Wheel friction
The problem comes in when using wheels that make contact on their width such as rubber or polyurethane. These will deform and "squirm" when forced along the track.
It still might be of minor concern, but if this is something you must quantify, it may require experimentation....perhaps the axes being canted.
If you're looking for power requirements to turn the table under load, there are a lot more variables to consider; the main one being rolling resistance of the wheels.
RE: Wheel friction
RE: Wheel friction
You might want to look round this site to:-
http:/
desertfox
RE: Wheel friction
MintJulep: Where can I find out more about these things? Can you please advise me a book or other recource. Thanks again!
RE: Wheel friction
The major axial force, F, is the centripetal force on the bearing of mass m
F=mw^2
w= angular velocity of the turntable
RE: Wheel friction
F=m*w^2*r
r radius of turntable
RE: Wheel friction
Any statics and dynamics text book covers the fundamentals of this.
RE: Wheel friction
RE: Wheel friction
http://www.ntn.ca/pics/roller_guidance_pic1.jpg
http://ww
It may be possible to "steer" each roller bearing to reduce the axial load, but some cylindrical roller and track wear will still occur due to slipping. It Maybe easier to provide centering with a bearing in the center of the table, and mount the rollers on casters, to avoid having to machine the roller axle seats with great precision, or go thru an elaborate alignment adjustment.
Unless there is resilience somewhere between track and turntable (flexible turntable relative to loads, etc) I don't picture many of the 60 rollers carrying their share of the load