|
Tracy,
I guess that was directed at me, and that's a
Yes!
I had requested that info from the
Chief Engineer at Timken Australia, who provide those figures. If
memory serves me I quoted 3,000 RPM.
Butch suggested that 250,000 hrs was way overkill
!
That's not to say they are the best bearing for the job,
but they are a very robust bearing - that's for sure.
The big problem for any bearing is cooling, so a TRB
with much larger surface area than ( for
instance) a plain ball bearing, requires more cooling.
I had originally wanted to use TRB on my own Aussie
design, as an engineer mate explained - their so robust, but have been since coerced by Butch to consider other
options.
George ( down under)
One question, did you plug in the RPM used in this application when
calculating bearing life? It goes down real fast on some bearings
(especially tapered rollers).
Tracy
----- Original Message -----
Sent: Wednesday, February 09, 2005 5:30
PM
Subject: [FlyRotary] Re: PSRU -
hub/prop end
Ernest,
Seems like you have it completely under control,
if you researched the life
of the bearings, under the loads they carry
you will find that their
projected life would be something like 250,000
hours.
That's the answer I got from Timken! but the sizes may have been
different.
Anyway it gives you a bit of an idea.
George ( down
under)
> Did some research last night, and I am now very
comfortable with the
> taper bearing. There is in fact one on
the other end, but I was not
> considering it, because I view all the
forces trying to pull the hub off
> the shaft and the rear bearing
won't see much stress in that situation.
> Now I realize that the rear
bearing will be important to keep the hub
> aligned properly, and this
won't happen unless the correct preload is
> applied. I also
understand that the correct term for the load forces
> are axial and
radial, not longitudanal and lateral.
>
> >The nut will be
for preload, remember when you put it back on, that you
know
>
>the preload number.
> >
> >
>
>
>
> Unfortunately, the nut was finger tight and the keyed
lock washer had
> never been bent to lock it in place. I have no
idea what the preload
> number is or how to determine it. On
cars, we always just tightened the
> nut till there was no side play
in the wheel but it still spun freely.
> I would think that I'd want
it a little tighter in this application,
> since the forces will be
trying to open up the rear seal and the only
> thing stopping that
will be the preload...but I don't have a number to
> attach to 'little
tighter'.
>
> >Again go to a bearing supply company, I have
no doubt that there would be
a
> >standard seal to fit. Who ever
made this PSRU would look for standard
seal
> >sizes.
>
>
> >George ( down under)
> >
>
>
>
> Thank you, George. I looked over Tracey's website
(thank you, Tracey),
> and several other places. I think in the
application that this hub was
> meant for (a racecar wheel), that the
car's wheel was the seal. I have
> a 1/4" plate that will
sandwich nicely between the prop and the hub. I
> can easily
machine a recess into it for a standard seal (I think).
>
>
>> Homepage: http://www.flyrotary.com/
>
>> Archive: http://lancaironline.net/lists/flyrotary/List.html
>
>>
Homepage: http://www.flyrotary.com/
>>
Archive: http://lancaironline.net/lists/flyrotary/List.html
|