VW_01131_EN-2018 摩擦系数的测定.pdfVIP

GroupstandardVW01131

Issue2018-03

Class.No.:01712

Descriptors:coefficientoffriction,fieldtesting,testbolt,testnut,threadedconnection,tighteningtorque

DeterminationofCoefficientsofFriction摩擦系数的测定

ISO米制螺纹钢制机械紧固件

SteelMechanicalFastenerswithMetricISOThreads

为了缩短组装时间，螺栓和螺母通常分几个阶段拧紧，并进行快速预拧紧。最终拧紧操作通常在降低转速的情况下进行，并且

Preface越来越频繁地还使用扭矩来产生拧紧程序。随着旋转角度的增大，影响摩擦的其他因素也会发生作用。外部标准和法规没有充

前言分考虑到这一事实。

Boltsandnutsareusuallytightenedinseveralstageswithafastpre-tighteningstageinorderto

shortenassemblytime.Thefinaltighteningoperationisusuallyperformedwithreducedrotational

speedandincreasinglyfrequentlyalsowithtorque-to-yieldtighteningprocedures.Withlargeran‐

glesofrotation,additionalfactorsthathaveanimpactonfrictiontakeeffect.Externalstandards

andregulationsdonotsufficientlytakethisfactintoaccount.

Thefriction-influencingfrictionpartnersoftheboltsandnutscanhaveverydiversesurfacetex‐

tures.Noteveryconceivablefrictionpairingcanbesimulatedinstandardizedtests.Verysmooth

andcohesivesurfacesorsurfacesthatareveryroughduetotheprocessingandmaterialstructure

presenttheirownchallenges.Moreover,surfacedamagecanoccuronfastenedpaintedparts

whichleadstoextremefrictionconditionsandoftenproducesundesiredeffects.Screwingboltsor

screwsintodeepthreadedholesmadeinsoftmaterialsplaces