I think the wiki advice is limited to deep groove ball bearings and is
consistent with what I've seen in bearing catalogs i.e. ~20% of axial
rating is ok for thrust in the size ball bearings I'm familiar with (<2"
bore).
A spherical roller is designed to withstand angular shaft misalignment
or deflection which would occur when the tower leans a bit under heavy
load. OTOH, the top row of rollers aren't useful since all the load is
downward. A deep groove ball bearing can't take much angular shaft
misalignment. There are thrust spherical roller bearings with specified
radial loads. They are in the SKF web site catalog. However, I suspect
the bearing RTS uses is much more common, cheaper, is already mounted,
and has Chinese knockoffs available.
I have to wonder if a spherical plain sleeve bearing might be a better
choice since brinelling and fretting aren't a problem, but I've not
looked at the specs.
https://en.wikipedia.org/wiki/Brinelling
Best to contact the manufacturer for the capacity of the bearing you
want to use.
Grant KZ1W
On 7/14/2017 6:30 AM, Al Kozakiewicz wrote:
https://en.wikipedia.org/wiki/Ball_bearing#Direction_of_load
________________________________________
From: TowerTalk<towertalk-bounces@contesting.com> on behalf of Stan
Stockton<wa5rtg@gmail.com>
Sent: Friday, July 14, 2017 8:55 AM
To:TowerTalk@contesting.com
Subject: [TowerTalk] Bearings
I need an education on bearings. The question is the axial or thrust rating of
guesstimate thereof on bearings that do not show that spec. As example the bearing I
believe used on a RTS rotating tower is a ZF 5215S made by Rexnard I think. The radial
load is specified at greater than 50,000 pounds. Axial load is not specified. Is there
anyway to equate radial load to axial load other than to look at a bearing and say
"looks like it would handle a lot?"
Stan, K5GO
Sent from Stan's IPhone
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