PumPac 8000, 8000-BB and 8000-AAB Series

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Chester Jennings
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1 PumPac 8000, 8000-BB and 8000-AAB Series The PumPac 8000 Series consists of a matched set of 40 A) and 15 B) angular contact ball beargs with computer optimized ternal design. They are manufactured to ABEC- tolerances and are supplied with an ner rg centered mached brass cage. Also available is the 8000BB PumPac Diamond Series consistg of two 15 B) beargs a back-to-back DB) arrangement; and the 8000AAB Series consistg of two 40 A) beargs tandem, matched back-toback DB) with one 15 B) bearg. Each arrangement cpates a small amount of axial clearance, when clamped, to compensate f mountg fits and thermal growth. Series Page 8000 PumPac BB PumPac Diamond 8000AAB PumPac Triplex Set 11 Shaft and Housg Fits 12 Mountg Instructions 1 Equivalent Load and Life 14 Mimum Thrust Load Requirements 14 Life Calculation Examples

2 PumPac 8000, 8000-BB and 8000-AAB Series MRC Bearg Services The PumPac 8000 Series is used centrifugal pumps, large vertical electric mots, compresss, centrifuges, and other applications subject to thrust loads operatg at relatively high speeds. The beargs are mounted so that the 40 A) bearg takes the primary thrust load. Traditionally, matched sets of 40 angular contact ball beargs are used to obta maximum theetical fatigue life, but most stances only a fraction of the calculated life is actually achieved. At the heart of these premature failures are phenomena known as ball slidg and ball shuttlg the unloaded active) bearg. Angular contact beargs used high speed e.g. 00 ) pumps and other applications require a mimum axial load f proper operation. Without axial load, gyroscopic fces the unloaded bearg can cause the balls to rotate perpendicular to their true rollg axis and momentarily lose contact with the raceway. As a result, a microscopic wear lappg) process occurs givg the appearance of a burnished polished raceway. The oil film thickness separatg the ball and raceway is reduced, producg friction and heat which lowers oil viscosity and accelerates wear. This thermally unstable condition dramatically reduces bearg service life. The ma benefit of the PumPac system is that the 15 B) bearg is designed with considerably less ternal clearance than the 40 A) bearg, makg it less susceptible to the gyroscopic fces which result ball slidg shuttlg. The 15 bearg also provides additional radial stiffness helpg to mata the tegrity of the shaft and mechanical seals. The 40 loaded) bearg provides sufficient axial rigidity under the imposed thrust load. The PumPac is furnished with a one piece, ner rg land-guided, mached brass cage and is manufactured to meet ABEC- grade tolerances. Dimensional stability is assured by heat treatg the bearg s rgs and rollg elements f operation up to 75 F 190 C). F identification purposes, the 40 bearg is marked with the letter A, and the 15 bearg with the letter B. A V is etched on the outer rg surface of the pair so that the apex falls on the B bearg. The pair should always be mounted so that the V pots the same direction as the primary thrust load, which places this load on bearg A. Any reversg load is carried on bearg B. The PumPac is also available the 8000BB PumPac Diamond series, which consists of a matched set of 15 B) beargs a back-to-back arrangement. When mounted crectly, the markg on the outer rg surface fms a diamond. This series is desirable high speed, lightly loaded applications which axial loads are balanced, resultg reduced operatg temperatures and creased life. F applications volvg very heavy primary thrust loads, the PumPac may be furnished as a triplex set identified as the 8000AAB Series. It consists of two 40 A) beargs tandem matched back-to-back DB) with one 15 B) bearg. The outer rg surface of the set is marked with a V potg the direction of primary thrust. F applications havg a rotatg shaft and stationary housg, an ISO k5 shaft fit and an ISO H housg fit are recoended as shown the table on page 12. OTE: The basic radial load ratg, C, is calculated accdg to the actual bearg geometry and not accdg to ISO/ABMA Standards. 158

3 PumPac 8000 Series The PumPac 8000 Series consists of one 40 A) bearg and one 15 B) bearg. ABEC Tolerances MRC Bearg umber Be d Outside Diameter D Width B Fillet Radius 1) r a r b Dynamic C 4) 40 A) Basic Radial Load Ratg 2) Static Dynamic C 4) 15 B) Static Speed Ratg ) Grease Oil ) Fillet radius dicates maximum fillet radius on shaft housg which bearg cner will clear. 2) F thrust ratg of bearg A), multiply C by 1.75 and Co by.85. F thrust ratg of bearg B), multiply C by 0.8 and Co by ) Values have been determed through histical application and practice. F a me complete explanation, see page ) Ratg f one million revolutions 500 hours at ¹ ₃. 159

4 PumPac Diamond 8000-BB Series MRC Bearg Services The PumPac 8000-BB Series consists of two 15 B) beargs. ABEC Tolerances Basic Radial Load Ratg 2) Speed Ratg ) MRC Bearg umber Be d Outside Diameter D Width B r a Fillet Radius 1) r b Dynamic C 4) Static Grease Oil 8218BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB BB ) Fillet radius dicates maximum fillet radius on shaft housg which bearg cner will clear. 2) F thrust ratg multiply C by 0.51 and Co by ) Values have been determed through histical application and practice. F a me complete explanation, see page ) Ratg f one million revolutions 500 hours at ¹ ₃.

5 PumPac 8000-AAB Series The PumPac 8000-AAB Series consists of two 40 A) beargs and one 15 B) bearg. ABEC Tolerances Basic Radial Load Ratg 2) Speed Ratg ) MRC Bearg umber Be d Outside Diameter D Width B Fillet Radius 1) 40 AA Pair) 15 B) Dynamic 4) Static Dynamic 4) r a r b C C Static Grease Oil 8218AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB AAB ) Fillet radius dicates maximum fillet radius on shaft housg which bearg cner will clear. 2) F thrust ratg of AA) multiply C by 1.75 and Co by.85. F thrust ratg of B) multiply C by 0.8 and Co by ) Values have been determed through histical application and practice. F a me complete explanation, see page ) Ratg f one million revolutions 500 hours at ¹ ₃. 11

6 PumPac Shaft and Housg Fits MRC Bearg Services MRC Bearg umber Shaft Diameter k5) Fit Housg Diameter H) 1) Fit Shaft and housg limits to ISO k5 and H tolerances. Maximum Mimum Maximum Mimum T-T 1T-1T L 0-17L T-T 1T-1T L 0-17L T-T 1T-1T L 0-17L ,08 T-T 1T-1T L 0-19L T-T 1T-1T L 0-19L T-4T 2T-18T L 0-25L T-2T 1T-9T L 0-14L T-2T 1T-9T L 0-14L T-2T 1T-9T L 0-14L T-27T 1T-11T L 0-14L T-27T 1T-11T L 0-1L T-27T 1T-11T L 0-1L T-27T 1T-11T L 0-1L T-27T 1T-11T L 0-17L T-27T 1T-11T L 0-17L T-T 1T-1T L 0-17L T-T 1T-1T L 0-19L T-T 1T-1T L 0-19L T-T 1T-1T L 0-19L T-T 1T-1T L 0-19L T-9T 1T-15T L 0-2L T-9T 1T-15T L 0-25L T-9T 1T-15T L 0-25L 1) Cast iron steel housgs. F alumum other soft metal housgs make housg be limits same as bearg O.D. limits 2) T dicates tight, L dicates loose 12

7 PumPac Mountg Instructions PumPac beargs require proper mountg ientation with respect to the direction of the imposed primary thrust load, which must be taken by the 40 A ) bearg. They should be stalled so that the V etched on the O.D. of the beargs pots the direction of the primary thrust load, as illustrated below f PumPac 8000 and 8000 AAB arrangements AAB 1

8 PumPac Dynamic and Static Equivalent Radial Load and Life Ratg MRC Bearg Services The followg method considers only thrust load either direction with negligible radial load. F combed radial and thrust loads consult MRC Technical Services f analysis. Dynamic equivalent radial load Primary thrust on bearg A 40 ) P = 0.57 F A Reversg thrust on bearg B 15 ) P = YF A P = Dynamic equivalent radial load F A = Thrust load Y = Thrust load fact Z = umber of balls D = Ball diameter Static equivalent radial load Bearg A 40 ) P 0 = 0.2 F A Bearg B 15 ) P 0 = 0.5 F A P 0 = Static equivalent radial load F A = Thrust load, F A ZD 2 Lb, Y F A ZD 2, ) Size ZD 2 ZD 2 ZD 2 Size Size ch ch ch 8218B B B B B B B B B B B B B B B B B B B B B B B Values of Y f loads not shown are obtaed from chart at right. Life ratg L = Lh = C P n C 0n millions of revolutions) ) C P Hours) = Basic dynamic load ratg = Dynamic equivalent radial load = speed otes: F 8000BB series, see page 80. F combed radial and thrust loads please contact MRC Bearg Services. Mimum Thrust Load A Fact Size A Size A Size A Mimum Thrust Load F Angular Contact Ball Beargs Satisfacty operation of angular contact ball beargs requires sufficient traction fces between the balls and races to mimize damage caused by slidg skiddg. This is particularly imptant at high speeds where the ertia fces of the balls and cage and the viscous drag the lubricant can have a detrimental fluence on the rollg conditions. The mimum required thrust load can be determed from the followg fmula. F A = A OR F A = A n 00) 2 n 00) 2 ewtons Pounds Where, F A = Mimum thrust load A = Bearg design fact listed the followg tables n = Speed ote: F Duplex Beargs mounted tandem, multiply the sglebearg thrust value by the number of beargs tandem. 14

9 Dynamic equivalent radial load and life calculation examples PumPac 8000 Series Bearg size: 8 Speed: 500 Basic dynamic radial load ratg C): Bearg A = 1900 Bearg B = 170 Bearg A Primary thrust load F A 000 Equivalent load = 0.57 F A P = = 17 Life L C 1900 = = 150 Rev. 17) Life Lh C n P ) = 7171 Hrs Bearg B Reversg thrust load F A 00 F A /ZD 2 = 00/.19 = 12 Equivalent load = Y F A Y = 1.22 P = = 1220 Life L C 170 = = 2754 Rev. 1220) Life Lh C 170 0n P ) = 111 Hrs PumPac 8000 AAB Series Bearg size: 814 AAB Speed: 500 Basic dynamic radial load ratg C): Beargs AA = Bearg B = Beargs AA Primary thrust load F A 5000 Equivalent load = 0.57 F A P = = 2850 Life L C = = 954 Rev. 2850) Life Lh C n P ) = 11 Hrs PumPac Diamond 8000 BB Series Bearg size: 817BB Speed: 000 Basic dynamic radial load ratg C): C 200 Sgle bearg = = = ) Primary Thrust Bearg Primary thrust load F A 2500 F A /ZD 2 = 2500/1.5 = 152 Equivalent load = Y F A Y = 1.2 P = = 075 Life L C 8904 = 2025 Rev. P 075) Life Lh C n P ) = Hrs Reversg Thrust Bearg Reversg thrust load F A 00 F A /ZD 2 = 00/1.5 = 1 Equivalent load = Y F A Y = 1.8 P = = 180 Life L C 8904 = 180) = Rev. Life Lh C n P ) = Hrs Bearg B Reversg thrust load F A 1500 F A /ZD 2 = 1500/.5 = 14 Equivalent load = Y F A Y = 1.24 P = = 180 Life L C = = 127 Rev. 180) Life Lh C n P ) = Hrs 15

ENGINEERING INFORMATION TABLE OF CONTENTS SHAFT AND HOUSING FITS LUBRICATION LIFE AND LOAD RATINGS RADIAL CLEARANCE CHART

ENGINEERING INFORMATION TABLE OF CONTENTS ENGINEERING INFORMATION SHAFT AND HOUSING FITS LUBRICATION LIFE AND LOAD RATINGS RADIAL CLEARANCE CHART SHAFT AND HOUSING FITS FOR METRIC RADIAL BALL AND ROLLER