Page 568 - SKF-bearing-housings

Two-bearing housings PD series

Bearing arrangements accuracy of form should be to tolerance grade
Typically, PD two-bearing housings accommo- IT5 for shaft diameters up to and including
date a locating and a non-locating bearing. In 60 mm and IT6 for larger diameter shafts. At
some applications, however, both bearings are the seal position, the shaft (or shaft sleeve)
used to locate the shaft axially, each in one should comply with the same tolerance classes
direction. This is called a cross-located (“float- as the bearing seat.
ing”) bearing arrangement. SKF also supplies pre-machined shafts to fit
PD housings. Their designations are provided
in the product tables. The bearing seats and
Load carrying capacity shaft ends are machined to the tolerance
PD two-bearing housings are intended for classes listed in table 2 and table 3
loads acting perpendicularly toward the sup- respectively.
port surface. If the housing is supported over Shafts are supplied with two keys and two
its four feet and the loads are purely perpen- end plates with attachment screws.
dicular, loads are limited only by the bearings.
Housings in the PDN series that have bear-
ings preloaded with a wave spring washer
accommodate axial loads in one direction only.

Operating temperature
The permissible operating temperature is
mainly limited by the seals and lubricant. For
temperature limits of SKF bearings and lubri-
cants, refer to the product information avail-
able online at skf.com/bearings. For tempera-
ture limits of the seals used in PD housings,
refer to table 1 on page 559.
The housing material does not set any add-
itional temperature limits, except for very low
temperature applications where impact
strength could be a factor.
The housing paint is heat resistant up to
80 °C (175 °F) material temperature or 100 °C
(210 °F) ambient temperature.
When temperatures outside the permissible
range are expected, contact the SKF applica-
tion engineering service.

Operating speed
The permissible operating speed of the incor-
porated bearings is limited by the V-ring and
felt seals, but not by the housing. Speed limits
of the seals are listed in table 1 on page 559.

Shaft specifications
Shafts for two-bearing housings can be
machined according to the recommended
dimensions provided in product tables 13.4
to 13.7. The bearing seats should be machined
to the tolerance classes listed in table 2. The

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