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1、附錄A英文原文MachinetoolspindleunitsA.1IntroductionMachinetoolspindlesbasicallyfulfilltwotasks:rotatethetools(drilling,millingandgrinding)orworkpiece(turning)preciselyinspacetransmittherequiredenergytothecuttingzoneformetalremovalObviouslyspindleshaveastronginfluenceonmetalremovalrates
2、andqualityofthemachinedparts.Thispaperreviewsthecurrentstate.andpresentsresearchchallengesofspindletechnology.A.1.1.HistoricalreviewClassically,mainspindlesweredrivenbybeltsorgearsandtherotationalspeedscouldonlybevariedbychangingeitherthetransmissionratioorthenumberofdrivenpolesb
3、yelectricalswitches.Latersimpleelectricalorhydrauliccontrollersweredevelopedandtherotationalspeedofthespindlecouldbechangedbymeansofinfinitelyadjustablerotatingtransformers(WardLeonardsystemofmotorcontrol).Theneedforincreasedproductivityledtohigherspeedmachiningrequirementswhichl
4、edtothedevelopmentofnewbearings,powerelectronicsandinvertersystems.Theprogressinthefieldofthepowerelectronics(staticfrequencyconverter)ledtothedevelopmentofcompactdriveswithlow-costmaintenanceusinghighfrequencythree-phaseasynchronousmotors.Throughtheearly1980’shighspindlespeedswe
5、reachievableonlybyusingactivemagneticbearings.Continuousdevelopmentsinbearings,lubrication,therollingelementmaterialsanddrivesystems(motorsandconverters)haveallowedtheconstructionofdirectdrivemotorspindleswhichcurrentlyfulfillawiderangeofrequirements.A.1.2.PrincipalsetupToday,the
6、overwhelmingmajorityofmachinetoolsareequippedwithmotorizedspindles.Unlikeexternallydrivenspindles,themotorizedspindlesdonotrequiremechanicaltransmissionelementslikegearsandcouplings.Thespindleshaveatleasttwosetsofmainlyballbearingsystems.Thebearingsystemisthecomponentwiththegreat
7、estinfluenceonthelifetimeofaspindle.Mostcommonlythemotorisarrangedbetweenthetwobearingsystems.Duetohighratioof‘powertovolume’activecoolingisoftenrequired,whichisgenerallyimplementedthroughwaterbasedcooling.Thecoolantflowsthroughacoolingsleevearoundthestatorofthemotorandoftentheou
8、terbearingrings.Sealsatthetoolendofthesp