1、Designation:D 3337 91(Reapproved 2002)An American National StandardStandard Test Method forDetermining Life and Torque of Lubricating Greases inSmall Ball Bearings1This standard is issued under the fixed designation D 3337;the number immediately following the designation indicates the year oforigina
2、l adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.
3、Scope1.1 This test method describes a procedure for the determi-nation of grease life and torque in small bearings.Although thistest method is not the equivalent of a long-time field-servicetest,it is intended to predict the relative grease life at hightemperature in a reasonable period of testing t
4、ime.In addition,this test method measures the running torque at both low(1r/min)and high(12 000 r/min)speeds.1.2 Except for torque,which is measured in gcm,the valuesstated in inch-pound units are to be regarded as the standard inthis test method.The SI values given in parenthesis are forinformation
5、 only.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.2.Terminolog
6、y2.1 Definitions of Terms Specific to This Standard:2.1.1 grease lifea measure of the durability of the greasein a small bearing at elevated temperatures.2.1.2 grease torquea measure of the amount of frictiondue to viscous shear of the grease.2.1.3 running torquea measure of the amount of frictionin
7、 a rotating bearing due to load,speed,and viscous shear ofthe grease.3.Summary of Test Method3.1 Asingle row ball bearing with the test lubricating greaseis rotated at a high speed under a constant load and selectedtemperature.Total running time is determined at completion ofthe test as a measure of
8、 the durability of the grease.3.2 Running torque can be obtained for a single row ballbearing with the test lubricating grease rotating at 1 r/min and12 000 r/min.4.Significance and Use4.1 This test method is a screening test to differentiateamong the expected life of greases in ball bearings runnin
9、g athigh temperatures.If torque is a factor in selection of a grease,the test method provides for measurements at both low(1r/min)and high(12 000 r/min)speeds.5.Apparatus5.1 The apparatus required for this test method is describedin detail in Annex A1.A new R-4 bearing is used for each test.It is ru
10、n at 12 000 r/min12-lbf(2.2-N)radial load and 5-lbf(22-N)axial load.6.Reagents and Materials6.1 Grease SampleProcure the grease sample from belowthe surface of the grease container.Do not let separated oil getin contact with the sample;pour the excess oil off if present.Screen the grease using a 40-
11、m retention filter.A techniquefor screening is described in Annex A2.6.2 Test Bearing:6.2.1 Specificationsthe test bearing2is size R-4.6.2.2 Size0.2500 in.(6.350 mm)bore,0.6250 in.(15.875mm)OD,0.1960 in.(4.978 mm)wide.6.2.3 MaterialType 440C stainless steel,heat stabilized.6.2.4 Precision ClassAFBMA
12、(Anti-Friction BearingManufacturers Association)Class 7.6.2.5 Radial Clearance0.0003 to 0.0005 in.(0.007 to0.013 mm).6.2.6 Retainerstainless steel ribbon type.6.2.7 Shieldsremovable with snap rings.6.2.8 Packagingbearing,shields,and snap rings packagedindividually in clean and sealed envelopes.7.Gre
13、ase Packing of Test Bearing7.1 Pack the test bearing in a clean environment with aquantity of test grease to fill one third of the free space in thebearing.1This test method is under the jurisdiction of ASTM Committee F34 on RollingElement Bearings and is the direct responsibility of Subcommittee F3
14、4.02 onTribology.Current edition approved Oct.10,2002.Published March 2003.Originallyapproved in 1974.Last previous edition approved in 1996 as D 3337-91(1996).2Asuitable bearing is Barden No.SR4SSW4,shipped without lubricant and withshields and snap rings unassembled,available from O.P.Schuman and
15、Sons,Inc.,County Line and Titus Rd.,Warrington,PA 18976.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.7.2 If it is necessary to determine the free space of aweighed bearing,place the bearing(with shields and snap ringsremoved)in a conta
16、iner of melted petrolatum of known densityunder vacuum.Let the petrolatum harden,remove bearing,andreplace shields and snap rings.Clean the bearing of excesspetrolatum and determine the weight increase.Using thedensity of petrolatum and bearing weight increase,compute thebearing free space.For the Barden bearing No.SR4SSW4,theone-third free space is 0.080 mL.7.3 The test bearing may be packed on either a weight or avolume basis.A small spatula or a small syringe3with a shortneedle can be used to
