[TheForge] OT - Grease/oil seals for a gear box

[Bruce Freeman]

Yeah, Grover also suggested this.  I could probably make it work, but
don't like the idea for two reasons:  (1) it would require a redesign
and remachining of several components, and (2) it would increase the
size of the assembly, possibly considerably.  Nonetheless, I'm going
to keep this idea in mind in case a redesign proves necessary.

On Fri, Jul 10, 2009 at 5:01 AM, Larry Brown<lp.brown at verizon.net> wrote:
>
> Bruce
> I would consider a slinger plate inside next to a sealed high speed
> bearing. The slinger would keep most of the oil off the bearing and the
> seal should hold the rest
> Larry
>
> At 11:33 PM 7/9/2009 -0500, you wrote:
>>Bruce Freeman wrote:
>> > Well, I am surprised!  I always thought of packing seals for plumbing
>> > applications like valve stems, where the rotating rate is about once
>> > per day!  I've looked up a little and find some of them are good for
>> > "high speed" applications, but I don't have enough info yet to
>> > determine what RPM that means.
>> >
>> > Does anyone know what considerations go into selecting design criteria
>> > and packing material for an application with speeds upwards of 2000
>> > RPM?  (I'm shooting for 10kRPM, but doubt I'll get there with this
>> > prototype, for reasons other than the packing seals.)
>>
>>snip
>>
>>What I gotta say is wow. 10000 rpm is a lot for a seal. I tend to think
>>that the only type of seal that will withstand that speed is a ceramic seal
>>see:
>>http://www.pumpseals.net/Outboard_seals.htm
>>for a look see.
>>The ceramic seals operate well at high speeds but the majority of
>>installations that I have seen them in are for pumping water... they are
>>therefor cooled by the water.
>>
>>If you can restructure the shaft and housing to accommodate a sealed
>>high speed bearing such as those found in an automotive alternator you
>>would be well served. The poor alternator operates at high rpm ( its
>>usually 'geared' up at least 2:1 and some times 3:1, if the crank is
>>turning 4000 rpm you can see what that does to the alternator shaft
>>speed). Those bearings are pre lubricated and shielded.
>>As a testament to their toughness the six bearings in my three cars,
>>100050 miles, 150000 mi and 132000 miles are all original. if you can
>>adapt your shaft and housing sizes that's the way I'd go...
>>Good luck
>>
>>--
>>Paul Sperbeck  WB9HCO
>>
>>   "The difference between genius and stupidity is that
>>genius has its limits." -Albert Einstein
>>"Life is hard...it's harder if you're stupid" John Wayne - Sands of Iwo Jima
>>"We started off trying to set up a small anarchist community, but people
>>wouldn't obey the rules." -- Alan Bennett
>>
>>No trees were killed in the sending of this message, but a large number
>>of electrons
>>were terribly inconvenienced.
>
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-- 
Bruce
NJ

The total lack of evidence is the surest sign that the conspiracy is working.