Page 33 - Y-bearing-units

This method is usually adequate for selecting
the size of Y-bearings or Y-bearing units, as it
is based on experience. If reference experience 1
regarding requisite life and operational reliability
is not available, the values provided in table 1 for
the basic rating life L 10h can be used as guide lines.
To fully exploit the life of a Y-bearing or
a Y-bearing unit, the modified life equation in
accordance with ISO 281:2007 should be used
to calculate the SKF rating life.

SKF rating life
In the SKF rating life equation, the stresses
resulting from external loads are considered,
together with the stresses caused by the surface
topography, lubrication and kinematics of the
rolling contact surfaces. Taking the influence of
this combined stress system into account pro-
vides a better prediction of the actual perform-
ance of the Y-bearing or Y-bearing unit in
a particular application.
For additional information about the SKF
rating life and its calculation refer to the:

• SKF General Catalogue
• SKF Interactive Engineering Catalogue
available online at www.skf.com

The SKF Interactive Engineering Catalogue
allows different bearing lives to be calculated
online.

Table 1
Guideline values of requisite basic rating life L 10h for Y-bearings and Y-bearing units
Type of machine Requisite basic
rating life L 10h
operating hours
Machines used for short periods or intermittently
Agricultural and ancillary transport equipment 1 000 to 2 000
Other agricultural equipment 4 000 to 8 000
Machines used 8 hours per day but not always fully utilized
Belt conveyors 12 000 to 20 000
Machines used 8 hours per day and fully utilized
Light duty fans, textile machinery 20 000 to 30 000

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