STAR – Precision Ball Screw Assemblies

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STAR – Precision Ball Screw Assemblies End Bearings, Calculation Resulting and equivalent bearing loads Angular contact thrust ball bearings are preloaded. The chart shows the resulting axial bearing load Fa as a function of preload and axial operating load FaB zeigt das Diagramm. If the system is primarily subject to axial operating loads, then F = Fa . α = 60° X Y Fa Fr Fa Fr ≤ 2.17 > 2.17 1.9 0.55 0.92 1 α = pressure angle X, Y= dimensionless factor Fa = resulting bearing load FaB = operating load If the radial operating forces are not insignificant, the equivalent bearing loads are calculated according to formula 20 . Bearings for ball screw assemblies are also able to accommodate tilting moments. As a rule, the moments that usually occur due to the weight and drive motion of the screw do not need to be incorporated in the calculation of the equivalent bearing load. F = X · F r + Y · F a 20 Internal preload limit and resulting bearing load RResulting bearing load F a (N) 18000 17000 16000 15000 14000 13000 12000 11000 10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 d = 10 d = 6 1) Four row version d = 17 d = 12 d = 20 2000 4000 6000 d = 35 d = 30 Limits F r = radial bearing load (N) F a = resulting axial bearing load (N) F = equivalent bearing load (N) d=25 10 8000 10000 12000 Operating load FaB (N) 100 RE 83 301/12.99 1) d=30 1) d=40 d=50 14000 16000 18000
Average speed and average bearing load If the bearing is subject to varying axial loads over time, the average axial bearing load can be calculated using formula 21. If the speed varies, apply formula 22. In these formulas, the qi values represent the discrete time steps in %. If the radial load Frm varies, calculate the average radial load in the same manner. Service life and load safety factor Nominal life The nominal life is calculated as follows: Static load safety factor The static load safety factor for machine tools should not be lower than 4. Friction The bearing friction torque M RL is primarily dependent on the bearing preload. The influence of the operating load F aB is insignificant as long as it does not exceed the limits at which the bearings have zero clearance. The bearing friction torque M RL gspecified in the Dimension Tables applies to the preload generated by means of the slotted nut tightening torque R aL . The bearing preload is selected so as to allow it to remain effective even at high operating loads and ensure that the bearing has zero clearance. RE 83 301/12.99 101 Fam 3 3 F1 n1 nm q1 100 3 F2 n2 nm q2 100 3 Fn nn nm qn 100 21 n m q1 100 q + 2 n1 100 n2 qn nn 100 22 L 16666 Lh n N RL C F 3 S 0 = C 0 F 0 M RL n 9.55 23 25 C F 26 3 24 F am = resulting average axial load (N) q = time fraction (%) n m = average speed (min -1 ) L = nominal life (10 6 revolutions) in millions of revolutions L h = nominal life in operating hours (h) C = dynamic bearing load rating (N) n = average speed (min -1 ) F = equivalent bearing load (N) S 0 = static load safety factor (-) C 0 = static load rating (N) F 0 = maximum static load (N) The bearing friction torque M RL is measured at a speed of n = 5 min -1 . The friction power loss N RL of the bearing can be calculated using formula 26 . The various operating speeds n i must be incorporated in the heat balance as a function of their time fractions q i . N RL = friction power loss (W) n = speed (min -1 ) M RL = bearing friction torque (Nm)
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RE 83 301/12.99 STAR - Precision Ba
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STAR - Precision Ball Screw Assembl
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End machining details Bearings LAF
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Short nut length Available ex stock
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High axial load capacity Low fricti
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RE 83 301/12.99 11 Folding press La
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Nut types All nuts can be combined
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Order Code Precision Ball Screw Ass
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Ball screw with annealed ends For m
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D 5 Lube port at flange center L 3
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D 5 D 1 +0.7 L 5 L 3 L N.B.: On a p
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Lube port at flange center D5 +0.7
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Lube port at flange center L5 D5 D1
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L 11 RE 83 301/12.99 27 L L 6 L 7 L
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H 1 6x60° D 1 RE 83 301/12.99 33 E
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H 1 90° D 1 2 x B RE 83 301/12.99
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Friction-welded blanks made of prec
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Area of application The STAR - Grou
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Screw End Form 00, End not Annealed
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End Bearings for Screw Ends Form 01
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Page 49 and 50: End Bearings for Screw Ends Form 31
Page 63 and 64: H 2 D B 6 B 2 B RE 83 301/12.99 63
Page 65 and 66: H 2 D d B 2 B D 1 RE 83 301/12.99 6
Page 67 and 68: B1 H1 H2 B4 B4 H4 H3 B2 S3 L3 L2 2
Page 69 and 70: H1 H2 H4 H3 B1 RE 83 301/12.99 69 L
Page 71 and 72: D D LGF-B-… LGF-A-… with slotte
Page 73 and 74: D D LGN-B-… LGN-A-… with slotte
Page 75 and 76: Dimensions (mm) Weight complete d D
Page 77 and 78: Housing nut GR - for angular contac
Page 79 and 80: Load-carrying capacities and servic
Page 81 and 82: Symbol definitions (excerpt): l0 =
Page 83 and 84: Axial run-out t 8 ´ of the shaft (
Page 85 and 86: Overall Rigidity The rigidity of a
Page 87 and 88: Screws with single nuts 2% preload
Page 89 and 90: R nu (N/µm) Screws with double nut
Page 91 and 92: Inserting the wiper-type seal Posit
Page 93 and 94: For NLGI 2-greases: The nut has to
Page 95 and 96: Calculation Example Service life Op
Page 97 and 98: Permissible axial load on screw F k
Page 99: Lubrication, Mounting the Housing M
Page 103 and 104: Rexroth Star GmbH D-97419 Schweinfu
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STAR – Precision Ball Screw Assemblies

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