Page 145 - Rollingbearings

Selecting its
Magnitude of load Precision Ease of mounting
requirements and dismounting
The ring of a bearing deforms proportion-
ately to the load For rotating inner ring
loads, this deformation can loosen the inter- To minimize delections and vibration in pre- Loose its are beneicial for easy mounting
ference it between the inner ring and shaft, cision or high-speed applications, interfer- and dismounting In applications where
causing the ring to creep on its shaft seat ence or transition its are recommended interference its are required for both the
The heavier the load, the tighter the inter- shaft and housing seat, separable bearings
ference it required The required interfer- or bearings with a tapered bore should be
ence can be estimated using: considered Bearings with a tapered bore
Design and material can be mounted on tapered sleeves (ig. 2)

JKK or on a tapered shaft seat (ig. 3)
P
d
∆ = 2,5 F K of the shaft and
r B

housing
where
Δ =required interference [µm] Distortion of the bearing rings caused by Axial displacement of
d = bearing bore diameter [mm] shaft or housing design, for example by dis- the bearing in the
B = bearing width [mm] continuities of the seat or uneven wall thick-
F = radial load [kN] ness, should be avoided non-locating position
r
For split housings, SKF generally recom-
Where sudden load peaks or vibration mends loose its The tighter (less loose) the When a non- locating bearing needs to be
occurs, a tighter it can be required it is in a split housing, the higher are the able to move axially on its seat, the ring sub-
requirements for the geometrical tolerances jected to the stationary load should have a
of the seat Split housings machined to tight loose it For additional information about
tolerances, such as SKF plummer block bearings in the non-locating position, refer
Temperature housings, can be used for transition its up to to Arrangements and their bearing
differences K7 Bearings mounted in thin -walled hous- types, page 70

ings or on hollow shafts require tighter
In operation, bearing rings normally reach a interference its than those recommended
temperature that is higher than that of the for robust cast iron housings or solid shafts
components to which they are itted This (Tolerances for seats on hollow shafts,
can loosen the it on the shaft seat, while page 146) Bearing interfaces
outer ring expansion can prevent the desired Shafts or housings made of materials
axial displacement in the housing other than steel or cast iron may require
Rapid start-up can loosen the inner ring different its depending on material strength
it when the frictional heat generated by the and thermal properties
bearing is not dissipated quickly enough In B.6
some cases, friction from seals can generate
enough heat to loosen the inner ring it
External heat and the direction of heat
low can have an effect on its Steady-state
and transient conditions must be considered
For additional information about tempera-
ture differences, refer to Selecting internal
clearance or preload, page 182 Fig. 2 Fig. 3
Bearing with a tapered bore mounted on a Bearing with a tapered bore mounted on a
plain shaft with an adapter sleeve tapered seat

143