ASTM_D_3527_-_15.pdf

Designation:D352715Standard Test Method forLife Performance of Automotive Wheel Bearing Grease1This standard is issued under the fixed designation D3527;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers a laboratory procedure forevaluating the high-temperature life performance of wheelbearing greases when tested under prescribed conditions.NOTE1Changes to this test method in the 1985 revision increased testseverity.Results will not be comparable with data from earlier procedures.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.2.1 ExceptionApparatus dimensions in inches are to beregarded as the standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specificwarning statements,see 8.1 8.4.2.Referenced Documents2.1 AFBMA Standard:AFBMA Standard 19,1974(ANSI B.3.19-1975)23.Terminology3.1 Definitions:3.1.1 lubricant,nany material interposed between twosurfaces that reduces the friction or wear between them.3.1.2 lubricating grease,na semi-fluid to solid product ofa dispersion of a thickener in a liquid lubricant.3.1.2.1 DiscussionThe dispersion of the thickener forms atwo-phase system and immobilizes the liquid lubricant bysurface tension and other physical forces.Other ingredients arecommonly included to impart special properties.3.1.3 thickener,nin lubricating grease,a substance com-posed of finely-divided particles dispersed in a liquid lubricantto form the products structure.3.1.3.1 DiscussionThe solid thickener can be fibers(suchas various metallic soaps)or plates or spheres(such as certainnon-soap thickeners)which are insoluble or,at the most,onlyvery slightly soluble in the liquid lubricant.The generalrequirements are that the solid particles be extremely small,uniformly dispersed,and capable of forming a relatively stable,gel-like structure with the liquid lubricant.3.2 Definitions of Terms Specific to This Standard:3.2.1 automotive wheel bearing grease,na lubricatinggrease specifically formulated to lubricate automotive wheelbearings at relatively high grease temperatures and bearingspeeds.3.2.2 grease life,n of wheel bearing grease,amount oftime operated under prescribed conditions of load,speed,andtemperature until preset torque limit is exceeded.3.2.2.1 DiscussionThe off-time,which is part of the 20 hand 4 h off-cycle,is not recorded and is not included as part ofgrease life.4.Summary of Test Method4.1 The test grease is distributed in the bearings of amodified,automobile front wheel hub-spindle-bearings assem-bly.While the bearings are thrust-loaded to approximately111 N,the hub is rotated at 1000 rpm and the spindletemperature maintained at 160 C for 20 h,4 h off operatingcycle.The test is terminated when grease deterioration causesthe drive motor torque to exceed a calculated motor cut offvalue.Grease life is expressed as the accumulated on-cyclehours.5.Significance and Use5.1 This test method differentiates among wheel bearinggreases having distinctly different high-temperature character-istics.It is not the equivalent of longtime service tests,nor is itintended to distinguish between the products having similarhigh-temperature performance properties.5.2 This test method has proven to be helpful in screeninggreases with respect to life performance for automotive wheelbearing applications.6.Apparatus6.1 Test Assembly(see Fig.1 and Fig.2).1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.G0.05 on Functional Tests-Temperature.Current edition approved April 1,2015.Published April 2015.Originallyapproved in 1976.Last previous edition approved in 2011 as D3527 11.DOI:10.1520/D3527-15.2Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.1.1 Custom-made Wheel Hub-Spindle-Bearing Assembly(Fig.3).6.1.2 Oven,electrically heated by a 1200 watt heater,thermostatically controlled to maintain spindle temperature at160 6 1.5 C.6.1.3 Spindle Drive Motor,14hp,120 volts dc with 1725rpm speed control the hub;motor torque is indicated by a meterequipped with an adjustable,automatic cut-off.6.1.4 Fan Drive Motor,130hp,120 v dc,1550 rpm.6.2 Motor speed,oven temperature,spindle tem