1 rbc ball screws 1.1 classification of ball screws pages precision metric series mm-series external ball return tube integral flange 36-37 38-39 im-series internal ball return deflector integral flange inch series gn-series external ball return tube integral flange gv-series external ball return tube std v-thd mounting optional flange rb-series high helix-large lead external ball return tube std v-thd mounting optional flange p-series miniature-fine lead rolled metric series rms-series external ball return tube std v-thd mounting optional flange rs-series external ball return tube std v-thd mounting optional flange m-series miniature-fine lead 40-47 rbc ball screws 48-49 50-52 53 56-57 inch series 58-60 61 4
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4.2 mounting accuracy tolerances to use a ball screw correctly and achieve long life with trouble free operation correct specification of geometrical tolerances is very important rbc s measurement processes conform to both iso jis standards for ball screw measurement rbc will help you determine the tolerance levels as they vary with accuracy level 1 bearing runout with respect to the ball groove 2 journal runout with respect to the ball groove 3 shoulder perpendicularity with respect to the bearing diameter 4 nut flange perpendicularity with respect to the ball groove 5 nut body concentricity with respect to the ball groove 6 nut flat parallelism with respect to the ball groove 7 total indicated runout of the threaded portion of the shaft with respect to the shaft center line all rbc ball screws are manufactured inspected and guaranteed to be within specifications a 4 g 3 c b 3 ggggcaggdaagabada 1 7 1 5 2 a 6 a fig 4.2 mounting accuracy and tolerances 11
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5.5 precautions for screw design 5.5.1 thread runoff adjacent diameter the following considerations should be given to ensure an economical design for your ball screw application the ball thread runoff must extend off one end of the screw shaft for the following ball nut models this is to facilitate the loading of the ball nut package a internal deflector type b yoke deflector type c flange/base mount housing type 5.5.2 hardness/transition zone rbc s ball screw shaft is induction hardened thus an incompletely hardened zone may be present at each end of the screw thread area depending on the design please consider this when designing the effective stroke consult rbc for details 6 nut design 6.1 nut selection 6.1.1 series the required accuracy delivery size and ball nut style must be considered when selecting the proper series for your application 6.1.2 ball re-circulation type select the ball re-circulation type according to the ball nut mounting and application standard external retur
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8 service life the service life of ball screws should be considered in terms of both wear life and fatigue life accuracy deterioration due to wear is largely influenced by operating conditions lubrication effectiveness etc 8.1 wear life normal maintenance lubrication and the use of contamination prevention devices such as bellows or telescopic covers will keep wear to a minimum the amount of wear is proportional to the number of cycles under load that the system experiences severe operating conditions such as high speed oscillation less than one turn or hostile dirty environments will shorten the wear life 8.2 fatigue life the fatigue life of the ball screw may be estimated from the basic dynamic rated load as is the case of rolling bearings 8.2.1 basic dynamic rated load ca the basic dynamic rated load is an axial load which allows 90 of a group of identical ball screws rotated under the same conditions to rotate without flaking for 1 million revolutions this basic dynamic rated load
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11 rbc part number the part numbering system used by rbc distinguishes the product and is composed of basic specifications this system is used for drawings orders and identification of product 11.1 standard precision series example gn1005 1 position 1 position 2 position 3 r 2 3 3 0350 a 4 5 c 6 o 7 position 4 position 5 position 6 position 7 indicates series type indicates thread directionrh or lh indicates iso lead accuracy class 1 0.0002 ft class 3 0.0005 ft class 5 0.001 ft class 7 0.002 ft class 9 0.006 ft indicates shaft length inches indicates ball nut style a std singlenut 2-circuit non-preload w/flange b std singlenut 2-circuit preload w/flange c std singlenut 2-circuit non-preload w/v-thd d std singlenut 2-circuit preload w/v-thd e std singlenut 4-circuit preload w/flange f std singlenut 4-circuit preload w/v-thd g std doublenut 4-circuit preload flange to flange h std doublenut preload flange mount housing i std doublenut preload base mount housing j std doubl
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12.2 im series metric internal ball return integral flange abdfec major model no screw dia mm in im1605 im2005 im2505 im3205 im4005 im4010 im5005 im5010 im6310 im8010 16 20 25 32 40 40 50 50 63 80 0.614 0.772 0.969 1.244 1.559 1.559 1.949 1.949 2.461 3.130 0.1378 0.1378 0.1378 0.1378 0.1378 0.2812 0.1378 0.2812 0.2812 0.2812 ball dia lead mm abcd max efgh 5 5 5 5 5 10 5 10 10 10 2.165 2.205 2.850 3.250 3.540 6.260 4.985 6.365 6.615 8.270 0.393 0.393 0.393 0.472 0.472 0.550 0.630 0.630 0.710 0.790 0.393 0.393 0.393 0.393 0.393 0.630 0.630 0.630 0.630 0.630 1.1021 1.3776 1.5744 1.9681 2.4800 2.4800 2.9524 2.9524 3.5428 4.1334 1.097 1.373 1.569 1.963 2.475 2.475 2.947 2.947 3.538 4.128 1.890 2.165 2.440 3.150 3.660 3.660 4.330 4.330 4.920 5.710 1.575 1.732 1.890 2.441 2.756 2.756 3.346 3.346 3.740 4.331 0.217 0.217 0.260 0.354 0.354 0.354 0.433 0.433 0.433 0.531 dimensions in inches unless specified 38
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12.3 gn series inch external ball return integral flange flange mount housing continued ghfd 0.40 0.40 0.40 0.40 0.43 0.40 0.44 0.77 0.77 0.44 0.77 0.75 e 4.680 5.640 4.680 4.740 5.640 4.740 5.640 10.420 10.420 5.630 10.420 10.875 f 3.18 3.62 4.12 4.50 4.50 5.50 5.50 7.12 7.50 6.00 7.50 8.25 g 0.281 0.281 0.344 0.344 0.344 0.406 0.406 0.531 0.531 0.406 0.531 0.531 h 2.750 3.187 3.562 3.937 3.937 4.812 4.812 6.187 6.562 5.312 6.625 7.312 dynamic load 10 inches lbs 2,241 3,682 2,800 2,986 4,462 3,342 4,963 20,855 21,958 25,380 22,948 26,587 6 max static capacity lbs 15,409 25,441 26,587 31,762 40,185 42,949 53,649 123,177 138,715 67,109 154,245 202,204 dimensions in inches unless specified 45
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12.5 rb series inch external ball return optional flange high helix large lead continued a j a 30° cbfbhgdedg fig 1 fig 2 model no rb0701a-b rb0702a-b rb1001a-b rb1020a-c rb1520e-f-g-h rb2001a-b-c-d rb2020e-f-g-h fig no 2 2 1 1 1 2 2 a 0.907 0.907 0.972 0.972 1.370 2.057 2.257 b 0.523 0.523 0.972 0.972 1.370 1.187 1.187 c 1.047 1.047 2.375 2.375 d 0.281 0.281 0.281 0.281 0.531 0.531 0.531 e 0.530 0.530 0.660 0.660 0.780 1.031 1.031 f 2.60 2.60 3.25 3.25 4.62 5.62 5.62 g 1.250-16 1.250-16 1.500-16 1.500-16 2.125-16 2.625-16 2.625-16 h 0.04 0.04 0.04 0.04 0.04 0.06 0.06 j .192 185 .192 185 .256 247 .256 247 .319 308 .383 370 .383 370 dimensions in inches unless specified 52
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13.2 rs series inch external ball return optional flange continued k2 45° k2 60° afbk1 fig 1 e k2 45° fig 2 k1 dchj type f k1 fig 3 i e max f max g max 0.468 0.665 0.667 0.667 0.787 0.787 0.797 0.917 0.959 0.983 0.983 1.191 1.190 1.185 1.185 1.191 1.200 1.199 1.281 1.576 1.576 1.916 1.733 1.564 1.566 1.737 1.737 2.010 2.010 2.330 2.545 2.371 2.381 3.356 0.55r 0.85r 0.86r 0.83r 0.80r 0.80r 0.80r 0.94r 0.90r 1.06r 1.06r 1.12r 1.05r 1.09r 1.08r 1.12r 1.17r 1.10r 1.22r 1.68r 1.68r 1.61r 1.53r 1.93r 1.88r 1.96r 1.96r 2.27r 2.27r 2.29r 2.48r 2.77r 2.66r 3.34r 0.50 0.50 0.46 0.46 0.50 0.50 0.50 0.50 0.50 0.50 0.50 h v threads 11/16-24 unef-2a 11/16-24 unef-2a 15/16-16 un-2a 15/16-16 un-2a 15/16-16 un-2a 15/16-16 un-2a 15/16-16 un-2a 15/16-16 un-2a 1.173-18 uns-3a 1.173-18 uns-3a 1 1/4-16 un-2a 1 1/4-16 un-2a 1 9/16-18 unef-2a 1 9/16-18 unef-2a 1 9/16-18 unef-2a 1 9/16-18 unef-2a 1 9/16-18 unef-2a 1 9/16-18 unef-2a 1 9/16-18 unef-2a 1 5/8-20 un-2a 2 1/4-20 un-2a 2 1/4-20 un-2a 2.548-18
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critical speed rotational speed of a ball nut or ball screw shaft that produces a resonant vibration of the ball screw shaft deflection elastic deformation the deformation of the ball screw assembly given an applied load deviation an actual quantitative measurement that is other than specified dimension specified quantitative measure and tolerance drag torque the actual force measured at a radius of a ball screw assembly with or without wipers drive torque the actual force including drag torque to actuate the ball screw assembly drunkenness the characteristic of a ball screw assembly under load and rotation the plane at the interface deviates in both concentricity and perpendicularity dynamic axial load rating the constant centric axial load that the ball screw can theoretically withstand for a basic rating life of one million revolutions efficiency 90 95 for ball screws measured by the following criteria load stroke surface finish rpm lubrication end journal the
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innovation commitment quality rbc bearings has been producing bearings in the usa since 1919 in addition to unique custom bearings rbc offers a full line of standard industrial and aerospace bearings including spherical plain bearings radial angular contact extended inner ring high misalignment quadlube® impacttuff® spreadlock® seal crosslube® duralubetm milltufftm bearings and self-lubricating bearings available in inch and metric sizes rod ends commercial and industrial precision mil-spec series self-lubricating and aircraft sold under the heim® unibal® and spherco® brands available in inch and metric sizes thin section ball bearings standard cross sections to one inch sizes to 40 inches stainless steel and other materials are available seals are available on all sizes and standard cross sections ball bearings precision ground semiground unground high loads long life smooth operation nicetm ball bearings are offered in caged and full complement configurations self-lubricating bearing
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