On 11/29/2014 04:01 PM, Gene Heskett wrote:
On Saturday 29 November 2014 14:23:01 Stuart Stevenson did opine
And Gene did reply:
seals create a lot of heat
That is a problem I have never had unless the seal was bone dry, in which
case it will quickly self-destruct anyway. Wet seals that are properly
sized don't get hot. Nor do they wear out for the equ of 200k miles.
If that is a problem, then the Christian Science oiling method isn't
working, and I'd rig it like Andy has pix of at a link in a recent
previous msg. The drilled holes I would aim to enter behind the bearing
but inside the seal, so both the seal stays wet, and the bearings get
slowly flushed.
My guess is that seals on slow speed and small diameter shafts work
well, but maybe not for high speed spindles and large diameter lathe
spindles. The Timken manual:
http://timken.com/en-us/products/Documents/Super-Precision-Bearings-for-Machine-Tool-Applications-Catalog.pdf
shows an example spindle with oil slingers, one on the outer side to
keep the coolant and dirt out, and one on the inside to keep the oil in.
Attached is a slightly embellished figure.
and an excerpt:
...
HOUSING SEALS
A labyrinth combination of slinger and end cover provides a highly
effective seal against the intrusion of foreign matter. This seal is
suggested for use over a wide range of speeds. For slower-speed
applications, a combination of slinger and a commercial contact-
type seal is usually employed.
Slingers should be machined all over to assure true-running. Their
diameters should be concentric with the bore. The outside diameter
of the slinger is often tapered to throw off cutting compounds,
coolants, etc., from the point at which such liquids may enter the
spindle. A drip or run-off groove adjacent to the open lip of the end
cover is highly desirable and practical.
The axial clearances of the internal faces between slinger and
end cover should be about 1.600 mm (0.0629 in.). The fi rst radial
clearance opening on any design through which liquid may pass
should be made very close, about 0.089 mm (0.0035 in.) on a side. The
inner radial clearances should be between 0.380 mm (0.0149 in.) and
0.190 mm (0.0075 in.).
...
--
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/
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