Influences on lifetime of wire ropes in traction lifts

摘要

Tractionliftsarecomplexsystemswithrotatingandtranslatingmovingmasses,springsanddampersandseveralsysteminputsfromtheliftsandtheusers.Thewireropesareessentialmechanicalelements.Themechanicalpropertiesoftheropesinusedependontheropeconstruction,theloadsituation,nonlinearitiesandtheliftdimensions.Themechanicalpropertiesareimportantfortheproperuseinliftsandtheridequality.Butfirstofallthewireropes(forallothersuspensionmeansaswell)havetosatisfythesafetyrelevantrequirementssufficientlifetime,reliabledeterminationofdiscardandsufficientandlimitedtractioncapacity.Thelifetimeofthewireropesbetterthenumberoftripsuntilropediscarddependsonalotofparametersoftheropeandtheropeapplicationeguseofplasticdeflectionsheavesandreversebendinglayouts.NewchallengesforropelifetimeareresultingfromthemoreorlessopenD/d-ratiolimitspossiblebycertificatesconcerningtheexaminationofconformitybynotifiedbodies.Thispaperwillhighlightthebasicsofwireropetechnology,theenduranceandlifetimeofwireropesrunningoversheaves,andthedifferentinfluencesfromtheropesandmoreandmoreimportantfromtheliftapplicationparameters.Veryoftenunderestimatedaretheinfluencesoftransport,storage,installationandmaintenance.Withthisbackgroundwewillleadovertothecalculationmethodsofwireropelifetimeconsideringtheactualfindingsofwireropeenduranceresearch.We'llshowinthispapernewandinnovativefactsastheinfluenceofropelengthandsizefactorinthelifetimeformular,thereductionoflifetimecausedbytractiongrooves,thenewmodelforthecalculationinreversebendingoperationsandthestatisticallyfirmedpossibilitiesformachineroomlesslifts(MRL)underverysmallbendingconditions...