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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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