super precision bearings

HANDLING OF SUPER PRECISION BEARINGSMounting · Special Super Precision Bearing Trainingings on the shaft by means of aprecision nut are indicated inTable 39. To rule out or reduce settingeffects, it is recommended toinitially tighten the nut with threetimes the indicated torque, loosenit again and then tighten it with thenominal torque.Clearance Adjustment in CylindricalRoller BearingsCylindrical roller bearings with taperedbore are mounted withclearance, zero-clearance or preload.This can be done to the precisionof ±1 µm with the help of anFAG boundary circle measuringdevice. If such a measuring deviceis not available, a fairly exact clearanceadjustment can be achievedby measuring the axial drive-updistance of the inner ring onto thetapered shaft seating, taper 1:12.This drive-up distance is 15 timeslarger than the radial expansion effectedin this way. Surface smoothingand the elastic behaviour ofthe spindle and the inner ring alsomake their contribution here.When mounting cylindrical rollerbearings, score marks can be safelyavoided if the inner ring is if possiblenot tilted relative to the outerring and the spindle is turned continually.Here, too, heating thehousing and the outer ring facilitatesthe mounting procedure.Test RunWith grease-lubricated bearings aspecial grease distribution procedurehas to be carried out prior toa test run. Details on grease distributioncan be obtained from Diagram27 (see page 147).ReportA quality assurance document iscreated by drawing up measuringreports during mounting and settinginto operation. Important measuringvalues are for example:• Seating diameter, interference• Spacer difference dimensions• Steady-state temperature• Radial and axial runoutSpecial Super Precision BearingTrainingThe handling of super precisionbearings as well as various mountingand measuring devices requiresa high degree of special expertise.The performance capacity of superprecision bearings can only be fullyexploited when the appropriatebearing is selected and mounted inthe correct way.FAG AC/SP has made it its businessto pass on the knowledgeabout the complicated processesin super precision bearings in speciallyconceived training programs.These offer differentiatedtraining concepts that are optimallytailored to the concrete requirementsof the respective targetgroups (master craftsmen, mountingoperators, engineers, commercialstaff).The training units deal with the improvementof existing designs byusing high-performance, innovativeproducts. In addition, they alsointroduce the latest newly developedproducts.The orientation of each specificsubject is kept as practical as possible.In addition to the required basicknowledge about function andapplication of super precisionbearings, assembly technicians areinvited to make themselves familiarwith the handling of mountingdevices and measuring instrumentsunder expert direction in FAGworkshops. As a rule, the trainingprograms include the followingcontents:FAG · 180