ntn rolling bearings handbook contents 1 1 rolling bearings 04 1.1 sliding friction and rolling friction 04 1.2 sliding bearings and rolling bearings 04 9 bearing internal clearance and preload 45 9.1 bearing internal clearance 45 9.2 internal clearance selection 46 9.3 preload 47 2 3 4 2 classification and characteristicsof rolling bearings 05 2.1 rolling bearing construction 05 2.2 classification of rolling bearings 06 2.3 bearing manufacturing process 08 2.4 characteristics 09 10 11 allowable speed 53 bearing characteristics 54 11.1 friction54 11.2 temperature rise 54 11.3 sound 55 5 6 7 8 9 10 11 12 13 14 15 16 17 3 bearing selection16 3.1 selection procedure 16 3.2 types and performance comparison 17 3.3 bearing arrangement 18 12 lubrication57 12.1 grease lubrication 57 12.2 oil lubrication 62 4 main dimensions and bearing numbers 19 4.1 main dimensions 19 4.2 bearing numbers20 13 14 external bearing sealing devices 65 bearing materials 66 14.1 raceway and rolling element material
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ntn rolling bearings handbook ˇcylindrical roller bearings because cylindrical roller bearings use rollers for rolling elements load capacity is large and the rollers are guided by the ribs of the inner and outer rings the inner and outer rings can be separated to facilitate assembly and tight fitting is possible for either types where either the inner or outer ring does not have a rib move freely in the direction of the shaft and therefore are ideal for use as so-called floating-side bearings that absorb elongation of the shaft types with a rib on the other hand can receive an axial load albeit slight between the roller end face and rib in order to further enhance axial load capacity there is the ht type that takes roller end face shape and rib into consideration and the e-type cylindrical roller bearing with a special internal design for raising radial load capacity the e-type is standard for small diameter size basic shape is given in table 2.5 besides these there are full complem
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ntn rolling bearings handbook 4 main dimensions and bearing numbers 4.1 main dimensions as shown in figs 4.1 4.3 main dimensions of rolling bearings include bearing bore diameter single outside diameter width/height and chamfer these dimensions must be known when mounting on the shaft and housing the main dimensions have been standardized by the international standards organization iso and the japanese international standard jis is used in japan the standard range of dimensions for single bore metric rolling bearings has been established as 0.6 2500 mm for single bore a code is used to express diameter series and width series which indicate the size of the bearing cross-section 4 brrrrrdrr1 r r r1 tcrrdebdd fig 4.1 radial bearing tapered roller bearings not included fig 4.2 tapered roller bearing diameter series 7 8 9 0 2 3 fig 4.3 diameter series of radial bearings table 4.1 dimension series code dimension series diameter series outer dimension radial bearing tapered roller bearing
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ntn rolling bearings handbook 6 load rating and life the total number of times the bearing can be turned without flaking due to rolling fatigue in 90 90 reliability of the bearings basic dynamic load rating expresses dynamic load capacity of rolling bearings and therefore refers to a certain load which provides basic rating life of one million revolutions basic dynamic load is expressed as pure radial load for radial bearings and pure axial load for thrust bearings basic dynamic load rating cr or ca is given in the ntn catalog dimensions tables 6.1 bearing life one of the most important factors when selecting bearings is the life of the bearing bearing life depends on the functions required of a machine fatigue life life of the bearing in terms of material fatigue caused by rolling lubrication life life of the bearing in terms of burning caused by deterioration of lubricant sound life life of the bearing in terms of obstruction of bearing function caused by increase of turning sound we
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ntn rolling bearings handbook table 7.3 bearing load of 3-point support bearings load and moment direction w a ra r o r 1 b rb r 2 c rc bearing load o 2 r 2r rb r 1 2r1r2 1 r w r rb 2 ra r 2 r w 0 r 1 r 2 rc o rw r rb 1 r 2 r mo 1 r 1 2 2r mo a ra r o r 1 b rb r 2 c rc rb 2r1r2 mo r 1 r 1 r rb 2 r 2 r 2 2r r 1 2 2r 2r 1 2 1 r ra 7 rc 1 m r rb w a ra r 3 r 1 r 2 b rb c rc rb 3 1 r r 2 r 2 w 3 r rb 2 ra r 2 r w 3 r 1 r 2 rc 3 rw r rb 1 r 2 2r r 1 2 2r 2r 1 2 3r 2 mo 3 r 1 1 r2 a ra r 3 mo b rb r 1 r 2 c rc rb ra mo r 1 mo r rb 2 r 2 r rb 1 r 2 rc r 1 35
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ntn rolling bearings handbook 8.4 pressure of fit surface the pressure that is produced on the fit surface and equation for calculating maximum stress are given in table 8.5 mean groove diameter for the inner and outer rings of the bearing can be approximated from table 8.6 interference that effectively works on fit surface pressure i.e effective interference deff is smaller than interference d theoretical interference calculated from dimension measurements of the shaft or bearing bore this is primarily due to the influence of finish surface roughness the following reduction amounts must therefore be anticipated grinding shaft 1.0 turning shaft 5.0 2.5 m 7.0 m table 8.5 pressure and maximum stress of fit surface fit conditions fit surface pressure fit of hollow e deff p steel shaft 2 d and inner ring fit of hollow e deff steel shaft p 2 d and inner ring fit of steel housing and outer ring fit of shaft and inner ring fit of housing and outer ring e deff 2 d 1 equation d di d/di 1 do/
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ntn rolling bearings handbook 0.04 0.04 axial displacement mm axial displacement mm 0c 72 05 c 0.03 0.03 72 c c 10 215 7 720 72 20 c 72 30 c 0.02 700 0b 0.02 0.01 b 7005 7010b 7015b 7030b 7020b 0.01 0 0 0.5 1.0 1.5 2.0 0 axial load fig 9.5.5 axial load and displacement for 70b series 2.5 103n 0 0.5 1.0 1.5 2.0 axial load fig 9.5.6 axial load and displacement for 72c series 2.5 103n 0.04 0.04 9 axial displacement mm 0.03 axial displacement mm 720 0.02 0 0.03 5 720 7210 7215 0.02 7200 b 0.01 7220 7230 0.01 7215b 7205b 7210b 7220b 7230b 0 0 0.5 1.0 1.5 2.0 2.5 103n 0 0 0.5 1.0 1.5 2.0 axial load fig 9.5.7 axial load and displacement for 72 series 2.5 103n axial load fig 9.5.8 axial load and displacement for 72b series technical data is based on typical figures the values therefore cannot be guaranteed 51
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ntn rolling bearings handbook 2 grease filling and replacement the amount of grease it takes to fill the bearing differs according to housing design space volume rotational speed and grease type the standard for filling is 30 to 40 of the bearing space volume and 30 to 60 of space volume for the housing use less grease if rotational speed is high or you want to hold down the temperature too much grease could cause temperature to rise grease to leak or performance to decrease due to deterioration be careful not to overfill the bearing with grease approximate value for space volume in the bearing is calculated by equation 12.1 v k w 12.1 replenished at suitable intervals replenishment interval differs according to bearing type dimensions rotational speed temperature and type of grease the standard is given in fig 12.3 this is however under normal operating conditions grease is also largely affected by temperature when the bearing temperature rises above 80°c make the replenishment interv
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ntn rolling bearings handbook 15 shaft and housing design bearing performance is largely affected by inclination deformation and creep according to shaft and housing design the following are therefore very important ˇbearing arrangement selection and method of fastening the bearing suited to the selected arrangement ˇsuitable shaft and housing fillet radius and shoulder height dimensions squareness runout ˇdimensions shape precision and roughness of fitted parts ˇouter diameter of shaft and housing including thickness variation inner ring fixing outer ring fixing 15.1 fixing of bearings when fastening a bearing to the shaft or housing the bearing must be fixed in the axial direction as well as fastening by interference with some exceptions in the case of an axial load bearing rings may move due to shaft flexure when cylindrical roller bearings are used as the floating side bearing and must therefore be fixed in the axial direction shaft shoulder height should not exceed groove bottom t
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ntn rolling bearings handbook 16.4 press fit and pullout force the force required to press fit or remove a bearing on/from a shaft or in/from a housing is calculated by the following equations for shaft and inner ring kd p d b for housing and outer ring p d b kd 16.1 16.2 inner ring bore shaft diameter mm inner ring raceway diameter mm hollow shaft bore d0 0 for solid shaft mm deff inner ring effective interference mm d outer ring outer diameter housing inner diameter mm de outer ring raceway diameter mm d0 housing outer diameter mm deff outer ring effective interference mm e modulus of longitudinal elasticity 2.07 106mpa 21 200kgf mm2 friction factor see table 16.1 b width of inner ring or outer ring mm d di d0 table 16.1 friction factor for press fitting and withdrawal applications when inner outer ring is press-fitted on/into cylindrical shaft hole when inner outer ring is withdrawn from cylindrical shaft hole when inner ring is press-fitted onto tapered shaft or sleeve
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ntn rolling bearings handbook name address phone office phone 83
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