Industrial shaft seals

gab.ru Берг АБ bergab@ya.ru Тел. (495)-228-06-21,
Industrial
факс
shaft seals
(495) 22
Table 8. Counterface tolerances for metric seals
Shaft diameter Diameter tolerance (h 11) Circularity tolerance (IT 8)
Nominal Deviation Deviation
d 1
over incl. high low max
mm µm µm
6 10 0 – 90 22
10 18 0 – 110 27
18 30 0 – 130 33
30 50 0 – 160 39
50 80 0 – 190 46
80 120 0 – 220 54
120 180 0 – 250 63
180 250 0 – 290 72
Table 9. Counterface tolerances for inch size seals
Shaft diameter Diameter tolerance Circularity tolerance
Nominal
Deviation
d 1
over incl. high low max
in in in
4 +0,003 – 0,003 0,002
4 6 +0,004 – 0,004 0,002
6 10 +0,005 – 0,005 0,003
Surface finish
It is also important that the machining
operation does not leave any directionality
behind on the counter surface, as this could
lead to leakage by pumping action, depending
on the direction of rotation. A suitable surface
can be achieved by plunge grinding; whole
number ratios of the grinding wheel speed to
the work piece speed should be avoided. The
grinding wheel should be dressed using a
cluster head dressing tool and the smallest
possible lateral feed, or a profile dressing roll
without lateral feed. The negative influence of
directionality in any particular case can only be
ascertained by test running under conditions of
alternating rotation.
The counter surface should be free of any
damage such as bruises, scratches, cracks, rust
or raised sections. It is therefore important
that it not only be carefully machined but also
that it be properly protected until final
mounting takes place. Such protection can, for
instance, be provided by threading a cardboard
tube over the counter surface, or preferably
over the whole shaft.
gab.ru Берг АБ bergab@ya.ru Тел. (495)-228-06-21, факс (495) 73 22