Hello Paul,

    I decided to e-mail you rather than reply on the main page in order

to keep traffic down.  My question concerns the helical gear and why it
doesn't create the same problems in cars that we see in re-drives?  It
looks to me like a helical gear is going to create thrust no matter what
it's geared to and probably encounter the same bearing problems regardless
of the application?  I'm no mechanic or engineer so I've probably missed
something like the forest for the trees, but maybe you can explain this in
a way a novice can understand.

Thanks,
Robin

Robin, another way to look at helical gears is to think of them as trying
to drive them selves apart. That side thrust must be absorbed either with a
thrust bearing. or as they do it in most gearboxes with an opposite cut
helical gear connected on the same shaft. If you look at a manual trans
cluster gear it will become obvious to you.

These thrust loads are absorbed by thrust type bearings which are either
special  high thrust ball bearings (Tracy gbox-prop thrust), tapered roller
bearings (auto wheel bearings), or Torrington type needle bearings
(generally small loads (Ross gbox-gear thrust). If you're really
interested, go to a  bearing supply store and look at their catalogs.

Ross must have assumed that the engine Torrington bearing was adequate for
the gbox thrust loads, but obviously it isn't, so everybody is adding a
thrust type bearing to take the load in the gbox instead of the engine.
Hope this helps.

Chuck H

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