Page 119 - Y-bearing-units

Tolerances Fig. 9
The tolerance for the shaft centre height H 1
(† fig. 9) is
• ±0,25 mm for plummer block units with
a bearing bore diameter ≤ 40 mm, except for
units in the SYK series, where the tolerance is
+/– 0,31 mm
• ±0,30 mm for the larger plummer block units.
For Y-bearing plummer block units with com-
posite or cast housings, the outside diameter of H 1
the bearing is matched to the diameter of the
housing bore so that the outer ring is prevented
from turning in its seat, but still able to compen- 3
sate for misalignment.
Additional information about tolerances for
the inner ring bore are listed in the section
Y-bearings on page 89. Load carrying ability of the housings
Housings made of composite material or grey
cast iron are able to withstand the same dynamic
Radial internal clearance and static loads as the Y-bearings they incorp-
The Y-bearing used in a Y-bearing plummer orate. These Y-bearing units can also be used in
block unit has the same radial internal clearance applications where shock loads or variable axial
as a similarly sized individual Y-bearing. loads occur.
Additional information about the radial inter- If SKF Y-bearing units are to be used in an
nal clearance can be found in the section application where health, safety, or the environ-
Y-bearings on page 90. ment is at risk, contact the SKF application engi-
neering service during the design phase.
Pressed steel housings have a lower load
Materials carrying capacity than their insert bearings.
Permissible radial loads are specified in the
Composite housings product tables. The axial load should not exceed
Y-housings in the SYK series are made of injection 20% of the permissible radial load.
moulded glass fibre reinforced polyamide 6. If the bearing arrangement will be subjected
A steel coil embedded in the housing adds to shock loads or variable axial loads, Y-bearing
greater stability to the form of the housing, units with a cast or Y-TECH housing should
even if operating temperatures are elevated. always be used.
The housing bolt holes are reinforced with
zinc-plated sheet steel inserts. The standard
housing colour is black.
Cast housings
Housings in the SY(J), SYH, SYM and SYF(J) series
are manufactured from grey cast iron
EN-GJL HB195 in accordance with
EN 1561:1997.

Pressed steel housings
Pressed steel housings in the P series are made
from cold-rolled sheet steel and are zinc-coated
for corrosion protection.

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