SKF - Industrial Shaft Seals

Radial shaft seals
Additional design options
HDS1, HDS2, HDS7 and HDSE seals can be designed
with an auxiliary PTFE lip to further protect
the bearing and sealing lip(s) from dust particles
in heavily contaminated environments, for example
mining and cement industries. The PTFE
lip is then positioned and directed as shown in
fig. 41.
The PTFE lip can also be positioned and directed
to provide additional lubricant retention
(† fig. 42).
The PTFE lip is clamped between the metal
case and the rubber seal body without significantly
increasing the total seal width. It has very
good chemical and wear resistance, can withstand
dry running and contributes to improved
sealing performance while only generating a
minimal friction torque. The combination of a
PTFE auxiliary lip and a sealing lip made of the
fluoro rubber compound SKF Duralife, developed
by SKF, creates a particularly effective sealing
solution.
Special care must be taken to prevent damaging
the PTFE lip during installation. Refer to
instructions in paragraph PTFE seals on page 85.
The letters F and H in the product name indicate
a PTFE auxiliary lip design including the
lip’s position and direction; see for example the
HDSF2 († fig. 41) and HDSH2 († fig. 42).
HDS1, HDS2 and HDS7 seals (with or without
an auxiliary PTFE lip) as well as the HDSA and
HDSB seals are available with an elastomer applied
to the outside diameter for use in applications
where bore temperatures reach maximum
100 °C (210 °F) († fig. 43). This design feature
has several important advantages:
• Compensates for imperfections in the housing
bore surface, improving the sealing performance
by minimizing bypass leakage.
• Prevents contaminants from entering
through gaps between housing bore and
the seal outside diameter at, for example,
out-of-round conditions.
• Minimizes the risk of damage to the housing
bore during installation and removal.
This design option is indicated by the letter K
in the product name; see for example the HDS2K
(† fig. 43).
air side
HDSF2
air side
HDSH2
air side
HDS2K
Fig. 41
oil side
Fig. 42
oil side
Fig. 43
oil side
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