The definitive answer. I guess "pre-load" wasn't the right term in
this case, and Steve was
right about the removing endplay. The idea is to take up the slack on
the bearings, without
any binding.
re:
"Pre-loaded bearings are used where extreme loads and/or very positive
location is required [ machine tools] or where high speeds are involved
[ rotation speeds]
These components usually require heavy pressing or heat to remove
bearings from their shafts as in big industrial gearboxes. Such
applications use oil lube and possibly cooling systems to control
temperatures. "
Like a Healey differential pinion gear bearing.
bs
Joe and Lenore Armour wrote:
> My View !
> The same size bearings are installed differently by different car
> designers depending on vehicle weight,dynamic forces,speed, braking
> power/heat etc.
> My six cyl. GMH Holden has the same bearing fitted WITHOUT spacers as
> the 3000 has with spacer.
> For ease of dismantling and maintenance the bearings are required to
> be a sliding fit on the axle.
> The risk is; that with load,speed and the accuracy of manufacture of
> the axle finished diameter the bearing may very slowly [ creep] rotate
> or fast [spin] on the axle. This may result in the inner bearing
> raceway [cone] welding itself onto the axle -- not good and has
> occured on my Holden,destroying the stub axle.
> To prevent the above problem some manufacturers lock the inner raceway
> to the axle as Healeys do, use a spacer and shims to enable the nut to
> force the outside bearing against the spacer against the inside
> bearing hard against the axle shoulder,preventing it from ROTATING.
> We ARE NOT pre-loading the bearings, we are end loading the bearings
> against the spacer/against the bearing/ against the shoulder. We are
> shimming the spacer to ensure there is some clearance in the bearings
> proper,that is the raceways to roller surfaces.
> This clearance is to allow for bearing expansion with increase in
> temp. from speed and brakes which will decrease these clearances. The
> nominated end float will have been calculated to result in a
> pre-determined bearing clearance approaching zero at max. expected
> temperature.
> Bearings prefer oil to run in as in industry and gearboxes etc. Oil
> is to difficult to keep in front hubs so grease is used. Always use
> the thinnest grease recommended with the minimum number of solid
> additives. Remember grease is really just a sponge to retain the oil
> lubricant held within it.
>
> Pre-loaded bearings are used where extreme loads and/or very positive
> location is required [ machine tools] or where high speeds are
> involved [ rotation speeds]
> These components usually require heavy pressing or heat to remove
> bearings from their shafts as in big industrial gearboxes. Such
> applications use oil lube and possibly cooling systems to control
> temperatures.
> Look up any website for the major bearing companies and check there
> installation procedures.
>
> Joe
> 40 yrs. in industry
> 40 yrs. in Healeys
> red one
> blue one
>
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Bob Spidell San Jose, CA bspidell@comcast.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
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