Industrial shaft seals

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Housing bore requirements, large diameter seals (LDS)
General
The following requirements are designed to
guarantee the requisite interference fit for the
seal, the necessary static sealing and proper
installation.
Housing bores for seals with steel shells
To ensure that the seal can be installed
without damaging it, the housing bore should
have a 5 to 10° lead-in chamfer. The transition
should be free from burrs and the transition
between the seal seating and the shoulder
should have a radius not exceeding 0,8 mm.
The depth of the housing bore (t 2 ) should be
at least 0,3 mm greater than the nominal seal
width b. The cylindrical section (t 1 ) of the bore
should have a width of at least 0,85 b, (fig 48).
Recesses in the housing shoulder, which
must be considered at the design stage,
considerably facilitate removal of a seal from
the housing bore, (fig 49).
Housing bores and end covers for HS and
HSF seals of elastomers
To ease installation and prevent damage to the
seals during mounting, the housing bore should
have a lead-in chamfer of 5 to 10°, fig 49. The
transition should be free of burrs and the
transition between seal seating and housing
shoulder should have a radius which does not
exceed R = 0,8 mm.
In contrast to the other radial shaft seals the
non-split and split HS and HSF seals must be
axially clamped in the housing bore. This is
usually achieved by an end cover screwed to
the housing wall. The real width of the seal is
between 0,4 and 0,8 mm larger than the
nominal width of the seal housing groove (t 2 ).
The axial clamping so achieved gives the HS
and HSF seal the requisite firm fit in the
housing and the correct form for efficient
sealing.
The actual seal outside diameter is
approximately 0,5 % to 2 % larger than the seal
housing bore.
The end cover should be sufficiently thickwalled,
depending on diameter and the axial
clamping distance, wall thicknesses of between
6 and 12 mm have been found appropriate.
The cover should be screwed to the machined
housing wall following the recommendations
given in fig 49. To provide additional protection
to the sealing lip against coarse contaminants
the inside diameter of the cover should be
some 6 to 8 mm larger than the shaft diameter
d 1 . There are no limits regarding the outside
diameter of the cover. To ease mounting and
any subsequent seal replacement, it is
recommended that the cover be made in two
halves and an even number of screws used.
The end face should be made plane parallel
and the machined housing wall should be at
right angles to the housing bore.
gab.ru 82 Берг АБ bergab@ya.ru Тел. (495)-228-06-21, факс (495) 22