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Timken bearing fundamentals
- 1. Rolling Mill IndustryTraining: Bearing Fundamentals WORLDWIDE LEADER IN BEARINGS AND STEEL
- 2. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Bearing Types and Features Tapered Roller Bearing Details TRB Setting TRB Mounting Bearing Metallurgy & Fatigue Mechanism TRB Fitting Practice Lubrication Agenda
- 3. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Bearing Types Friction bearings Plain Bushing Oil sleeve Anti-friction bearings Ball bearings Needle roller bearings Spherical roller bearings Cylindrical roller bearings Tapered roller bearings
- 4. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Angular Ball Spherical Ball Needle Plain Cylindrical Bearing Types
- 5. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Spherical Roller Bearings Features Self aligning… suitable for misalignment Large diameter rollers provide high load rating Mounted internal clearance is determined by fit and factory setting… C2, C0(N), C3, C4 Easy inspection Repairable
- 6. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Outer Ring Inner Ring Lubrication Hole and Groove Cage Roller Flange SRB Nomenclature
- 7. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Cylindrical Roller Bearings Features High radial load capability Separable races - this facilitates mounting & dismounting when interference fits are desired on inner and/or outer rings Mounted internal clearance is determined by fit and factory setting… C2, C0(N), C3, C4 Thrust capability with 3 flanges Repairable
- 8. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals CRB Nomenclature Outer Ring Inner Ring Cage Roller Flange (optional) Flange (optional) Flange Designations: N, NU, NJ, NF, NP, NUP, NJF, NU+HJ, NJ+HJ
- 9. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Ball Bearings Features Most popular roller bearing Simple design Non-separable races High speed capability due to point surface contact Capacity based on point contact Controlled internal clearances, adjustment achieved through interference fits Grooves in the raceways allow ball bearings to handle axial loads
- 10. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Ball Bearing Nomenclature Outer Ring Inner RingCage Ball
- 11. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Needle Roller Bearings Features Thin cross sections - suitable where radial space is limited Good radial load capability Marginal thrust load capability Nomenclature Same as for cylindrical
- 12. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Tapered Roller Bearings Features Line contact True rolling motion Combined load capability Adjustable internal clearance Positive roller alignment Increased system rigidity Easy inspection Repairable
- 13. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals TRB Components Cup Cone Cage Roller Rib
- 14. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals 2-Row Bearing Types TDITDO • 2 single cones/ Double cup • Set w/ cone spacer (cone adjusted) • Lube hole/ groove in cup • “Indirect” mounting • Float through outer race • Double cone/ 2 single cups • Set with cup spacer (cup adjusted) • “Direct” mounting •Float through inner race
- 15. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Roller Bearing Comparison TRB TRB CRB CRB CRB SRB CHARACTERISTIC RADIAL THRUST CAGED FULL THRUST RADIAL DOUBLEROW SINGLEROW COMPLEMENT DOUBLEROW SINGLEROW Pure Radial Load Excellent Unsuitable Excellent Excellent Unsuitable Excellent Pure Axial Load Good Excellent Unsuitable Unsuitable Good Fair CombinedLoad Excellent Fair *Fair Poor Unsuitable Excellent Moment Load Fair Poor Unsuitable Unsuitable Unsuitable Unsuitable High Stiffness Excellent Excellent Good Excellent Excellent Good QuietRunning Fair Fair Good Poor Poor Fair LowFriction Fair Fair Good Poor Poor Fair Misalignment Poor Poor Poor Poor Unsuitable Excellent Locating Position (Fixed) Excellent Good *Fair Fair Fair Good Non-Locating Position (Floating) Good Unsuitable **Excellent Fair Unsuitable Fair * Fair with Flanges on Inner andOuter Ring / Unsuitable Without
- 16. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Point vs. Line Contact Less friction and heat Higher Speeds Lower stress Higher load capacity
- 17. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals True Rolling Motion On apex design provides true rolling motion along race Apex
- 18. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals K = 1.5 - 2.2 K = 0.6 - 1.2 Combined Radial & Thrust K = dynamic radial load rating dynamic thrust load rating
- 19. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Positive Roller Alignment The small seating force ensures positive roller alignment Cup Resultant Cone Resultant Seating Force Cup Resultant Cone Resultant
- 20. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Setting = Axial Clearance Endplay provides axial clearance Preload is a compression force measured as axial overlap
- 21. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals TRB Setting
- 22. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals TRB Mounting Arrangements Direct mount is less sensitive to misalignment Adjustment through cups Prevalent for centered loads Indirect mount provides more rigidity Adjustment through cones Prevalent for overhung loads
- 23. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Single Row vs. Two Row Single row mounting requires adjustment Two row mounting is typically non-adjustable
- 24. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Bearing Material & Metallurgy Steel quality is a major factor in bearing life Quality is determined by cleanness Alloy / Chemistry affects properties of steel
- 25. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Cyclic Fatigue Mechanism Non-metallic inclusions can limit bearing life Spall will eventually occur over non-metallic inclusions Load ratings based on bearing life before spall occurs
- 26. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Bearing Life Improvement 1 10 100 1000 Total Length of Inclusion Stringers (mm/cm3) 0.00010.0010.010.1110 Time Line 1988198619831982pre-1980 0.00010.0010.010.1110 Time Line 1988198619831982pre-1980 L15.91 Life Estimates (million revs) Bottom Poured Precipitation Shrouded Precipitation Deoxidation Super Clean Airmelt (MAP) Vacuum Carbon Deoxidation Vacuum-Arc Remelted (1980) Bottom Poured Precipitation Shrouded Precipitation Deoxidation Super Clean Airmelt (MAP) Vacuum Carbon Deoxidation Vacuum-Arc Remelted (1980)
- 27. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Fitting Practice Tight fits for rotating race Exceptions: low speed applications, TQO work and back-up rolls, keyed bores Heavy duty tight fits for heavy loads and high speed (Limits for TH product) Loose or split fits suggested when adjustment is necessary and for stationary races
- 28. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Purpose of Lubrication Reduction of friction, wear and fatigue Corrosion prevention Transfer of heat Remove debris
- 29. WORLDWIDE LEADER INBEARINGS AND STEEL Rolling Mill Industry Training Bearing Fundamentals Oil Flow Through the Bearing Direct flow between cage I.D. and small cone rib Direction of oil flow High Speed High Speed Low Speed Low Speed Rolling Mill Speed Guidelines Max Rib Speed (FPM) Min System Lube 1,500 Grease 3,000 Oil Level 5,000 Ciculating Oil 5,500 Air/Oil or Oil Mist 6,000 Oil Jets Special High Speed Bearings with Ciculating Oil 10,000 Rib Speed = ∏∏∏∏ x Cone Rib Dia. X RPM 12 in/ft * Note: Work Roll Bearings are an exception to the rule *