Timken Cylindrical Roller Bearing Product Overview Part A
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Transcript of Timken Cylindrical Roller Bearing Product Overview Part A
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Timken Cylindrical Roller Timken Cylindrical Roller Bearing Product OverviewBearing Product Overview
Part APart A
Narrated by
David BeachMotion Industries Retired
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 2
Agenda
Features of CRB’sBasic designsRoller-raceway profilesCage designPrecisionApplication considerationsPart numbers
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Features and AdvantagesFeatures and Advantages
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 4
CRB Features Separable races for easier
installation Line contact for high radial
loads Single or multi-row designs Cylindrical or tapered bore Preset radial clearance Size range - 10-1600mm
bore
Assembly
Line Contact
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 5
Maximum radial load capability
Low friction, high speed capability (under pure radial load)
Extensive float capability Separable design - flexibility
at installation
P (radial load)
Advantages of CRBs
Inner Race Installation
Feature
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 6
Disadvantages of CRBs Very limited (up to 10% of
radial) or no thrust capability Limited ability to handle
misalignment conditions (<0.0005”/ in) T (thrust load)
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Basic DesignsBasic Designs
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 8
Single Row CRB - Basic DesignsNU Outer ring has two integral ribs Inner ring has a cylindrical OD
without ribs Supports heavy radial load Accommodates axial expansion or
contraction Axial displacement between rings with
minimum friction while rotating
N Inner ring has two integral ribs Outer ring has a cylindrical bore
without ribs
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 9
Single Row CRB - Basic DesignsNJ Outer ring has two integral ribs Inner ring has a single rib Supports heavy radial load Supports light unidirectional thrust load up
to 10% of radial load The thrust load is transmitted between
diagonally opposed rib faces
NF Inner ring has two integral ribs Outer ring has a single rib
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 10
Single Row CRB - Basic DesignsNP Outer ring has two integral ribs Inner ring has a single rib An abutting loose rib Carries light thrust loads in both directions Provides axial location May be used with RN or RU bearing to
accommodate axial expansion/contraction Shaft end play (float) is determined by the
bearing axial clearance
NUP Inner ring has two integral ribs Outer ring has a single rib An abutting loose rib
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 11
Double Row CRBs Sold as complete assembly,
ring roller cage assembly, or separable ring
Not currently a standard Catalog offering. Available in same size range as single row product.
Current designs use NN, NNU nomenclature
Standard cage design is a drilled pocket, finger style bronze retainer
NN
NNU
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 12
Thrust Cylindrical Roller
Good thrust capacity
TP – multi-row roller pocket configuration
TPS - self adjusting for initial static misalignment
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Roller-raceway Stress Roller-raceway Stress Distribution and Roller ProfilesDistribution and Roller Profiles
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 14
Stress Distribution Causes of non-uniform stress distribution
– Angular misalignment between shaft and housing– Shaft bores not machined or aligned correctly– Housing bores not machined or aligned correctly– Bearings not installed correctly– Extreme loads– Overturning moments
Lead to edge loading, edge stress, reduced life Roller profiling is a method for achieving more
uniform stress distribution
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 15
Roller Profile Considerations
Optimize on load and misalignment– Flat rollers– End tapered– Multi-radius dub (MRD)
Timken analysis tools can predict the optimum bearing profile.
Cylindrical Roller Bearing Product Overview
5/7/2007 CRB Product Overview 16
Roller Profile - MRD
Balanced stress distribution– Standard design– Or application
specific
Timken MRD profiles
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Timken Cylindrical Roller Timken Cylindrical Roller Bearing Product Overview Bearing Product Overview Part APart A
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