Outline Outline Fluid Film Thrust Bearings: Fluid Film Thrust - PDF document

Outline Outline Fluid Film Thrust Bearings: Fluid Film Thrust Bearings: n Basic Design Criteria Basic Design Criteria n Fundamentals, Damage Fundamentals, Damage n Thrust Bearing Monitoring Thrust Bearing Monitoring n Evaluation, & Repair Evaluation, & Repair Damage investigation n Damage investigation n Damage mechanisms n Damage mechanisms n VIBRATION INSTITUTE MEETING VIBRATION INSTITUTE MEETING Inspection n Inspection CHARLOTTE, NC n CHARLOTTE, NC n Repair Repair n Pioneer Motor Bearing Pioneer Motor Bearing May 2006 May 2006 Slide 2 Slide 2 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company History History History History n Without question Without question n However, almost However, almost n n the most the most immediately upon immediately upon significant significant discovery of the discovery of the mechanical mechanical wheel, the need wheel, the need invention in the invention in the for bearings was for bearings was world was: world was: also discovered: also discovered: The The Wheel Wheel Slide 3 Slide 3 Slide Slide 4 4 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company History History History History n Which has Which has n As one can As one can n n led to one led to one observe from this observe from this of the most of the most wooden wheel wooden wheel elusive dating to 2700 elusive dating to 2700 searches in BC, axels where searches in BC, axels where human used to allow human used to allow history history support by radial support by radial and thrust and thrust bearings: bearings: Slide 5 Slide 5 Slide 6 Slide 6 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company

Thrust Bearing Load Orientations: radial/thrust Thrust Bearing Load Orientations: radial/thrust n Support axial load from the process Support axial load from the process n n e.g. Water or steam pressure e.g. Water or steam pressure n Thrust runner surface n Thrust runner surface n n Generally flat Generally flat (<13 µ m = 0.0005 (<13 µ m = 0.0005” ”) ) n 16 µ µ in RMS n 16 in RMS n n Thrust bearing Thrust bearing n Generally circumferential segments n Generally circumferential segments n n Tend to be Tend to be “ “square square” ” - - length=width length=width n Trade- -off off n Trade n Larger loaded area gives more friction loss n Larger loaded area gives more friction loss n Slide 7 Slide 7 Slide Slide 8 8 (c) 2006, Pioneer Motor Bearing Company Thrust Clearance Thrust Load Thrust Clearance Thrust Load Typical operating clearance n Load capacity based on Load capacity based on n Typical operating clearance n n n Hydrodynamic pressure profile Hydrodynamic pressure profile n n Pad area Pad area n ( ) RUNNER RUNNER = π − n Nominally Nominally Area 0 . 25 * * OD 2 ID 2 n n Reduced by grooving Reduced by grooving n BEARING BEARING Human hair about Human hair about 75 µ µ m (0.003 75 m (0.003” ”) diameter ) diameter Typical operating clearance Typical operating clearance about 25 µ about 25 µ m (0.001 m (0.001” ”). ). Ref: ROTECH Ref: ROTECH Slide Slide 9 9 Slide Slide 10 10 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company Thrust Bearing Designs Thrust Bearing Designs Flat Washers Flat Washers n Flat Washer Flat Washer n Simple but useful Simple but useful n n only with minimal only with minimal n Flat Flat Babbitted Babbitted Face With Grooves Face With Grooves n speed and load speed and load n Taper Taper- -Land Land Babbitted Babbitted Face Face n conditions conditions Tilting Pad Thrust Bearing n Tilting Pad Thrust Bearing n Grease lubricated Grease lubricated n n Equalized Tilting Pad Thrust n Equalized Tilting Pad Thrust n Bearing Bearing Slide 11 Slide 11 Slide 12 Slide 12 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company

Flat Babbitted Babbitted Thrust Face Thrust Face Flat “Bumper Bumper” ” Thrust Thrust “ with Grooves with Grooves n Useful as a bumper, Useful as a bumper, n or locating bearing or locating bearing n Oil or grease Oil or grease n lubricated lubricated n No theoretical load No theoretical load n capacity capacity n Practical capacity Practical capacity n around 50 to 75 PSI around 50 to 75 PSI Babbitted Babbitted axial surfaces to resist motion of shaft collars. axial surfaces to resist motion of shaft collars. Babbitted Babbitted surface may have radial pockets or grooving. surface may have radial pockets or grooving. Slide Slide 13 13 Slide 14 Slide 14 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company “Bumper Bumper” ” Thrust Thrust Taper- -Land Thrust Bearing Land Thrust Bearing “ Taper Radial Radial grooves n Optimized for only Optimized for only grooves n enhance load enhance load one speed and load one speed and load capacity. capacity. combination combination n Taper for oil wedge Taper for oil wedge n formation is formation is machined into the machined into the bearing surface bearing surface n Alignment is critical Alignment is critical n to operation to operation n Practical load limit Practical load limit n 150 to 225 PSI 150 to 225 PSI Slide 15 Slide 15 Slide 16 Slide 16 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company Simple Tapered- -Land Thrust Land Thrust Simple Tapered Compound Tapered- -Land Thrust Land Thrust Compound Tapered Taper is steeper Taper is steeper at the inner at the inner diameter than diameter than at the outer at the outer diameter. diameter. Taper is Taper is generally generally 0.003” 0.003 ”- -0.007 0.007” ”. . Land region is Land region is visible. visible. Slide Slide 17 17 Slide Slide 18 18 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company

Fluid- -film Thrust Bearing film Thrust Bearing Tilting Pad Thrust Bearing Fluid Tilting Pad Thrust Bearing n Annulus controls axial position. Annulus controls axial position. n Self Optimizing based Self Optimizing based n n on applied load and on applied load and Maximum load capacity n Maximum load capacity speed speed n n Maximum Flexibility Maximum Flexibility n Tilting- -pad pad re: potential re: potential Tilting modifications modifications bearing bearing n Alignment is critical Alignment is critical n n Load Capacity in Load Capacity in n excess of 600 PSI excess of 600 PSI Slide Slide 19 19 Slide 20 Slide 20 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company Tilting Pad Thrust Bearings Non- -Equalizing Support Equalizing Support Tilting Pad Thrust Bearings Non Equalizing linkages correct for housing skew. Equalizing linkages correct for housing skew. Equalizing linkages do not correct for rotating collar skew. Equalizing linkages do not correct for rotating collar skew. Ref: Constantinescu, p. 354. Ref: Constantinescu, p. 354. Ref: Kingsbury literature Ref: Kingsbury literature Slide Slide 21 21 Slide Slide 22 22 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company Self Equalizing Tilting Pad Self Equalizing Tilting Pad Non- Non -Equalized Bearing Equalized Bearing Thrust Bearings Thrust Bearings n Maximum capacity in Maximum capacity in n given space given space n Self optimizing oil Self optimizing oil n film film n Can accommodate Can accommodate n collar to housing collar to housing misalignment misalignment n Not designed for Not designed for n dynamic dynamic misalignment misalignment n Load Capacity in Load Capacity in n excess of 600 PSI excess of 600 PSI Slide Slide 23 23 Slide 24 Slide 24 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company

Equalizing Linkages Anti- -Rotation Pins Rotation Pins Equalizing Linkages Anti Provides: Provides: Intent is to Intent is to equally load equally load Locates shell in housing Locates shell in housing each of the each of the •Circumferential • Circumferential thrust pads in thrust pads in spite of Prevent rotation of the cage Prevent rotation of the cage spite of variations in in the housing. variations in in the housing. pad thickness or pad thickness or misalignment of misalignment of the housing to the housing to the runner. the runner. Ref: Constantinescu, p. 354. Ref: Constantinescu, p. 354. Slide Slide 25 25 Slide 26 Slide 26 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company Combined Journal Thrust Combined Journal Thrust Oil Distribution Geometry Oil Distribution Geometry Bleeder Bleeder Axial groove Axial groove Lobed journal Lobed journal bearing bearing Tapered thrust Tapered thrust bearing bearing Spreader Groove Spreader Groove OIL INLET OIL INLET HOLE HOLE Radial groove Radial groove Bleeders Bleeders Slide 27 Slide 27 Slide 28 Slide 28 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company Thrust Bearing Flows Thrust Bearing Flows Tilting Pad Thrust Bearings Tilting Pad Thrust Bearings Rotation Rotation Ref. Kingsbury Ref. Kingsbury sales literature, sales literature, EQH EQH- -1. 1. Ref: Kingsbury literature Ref: Kingsbury literature Slide 29 Slide 29 Slide Slide 30 30 (c) 2006, Pioneer Motor Bearing Company (c) 2006, Pioneer Motor Bearing Company