ASTM_D_1478_-_11.pdf

Designation:D147811Standard Test Method forLow-Temperature Torque of Ball Bearing Grease1This standard is issued under the fixed designation D1478;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.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers the determination of the extentto which a grease retards the rotation of a slow-speed ballbearing by measuring starting and running torques at lowtemperatures(below 20C(0F).1.1.1 Torque measurements are limited by the capacity ofthe torque-measuring equipment.NOTE1When initially developed,the original dynamometer scalelimited the torque capacity to approximately 30 000 gcm;the originaldynamometer scale is obsolete,however.The suggested replacement scalehas not been evaluated;it could extend the limit to approximately 75 000gcm.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.The exception is torque values that are given in cgs-metric units,which are universally used in grease specifica-tions.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 specific hazardand warning statements,see 6.1.1,7.2,7.4,8.7,and 8.11.2.Referenced Documents2.1 ASTM Standards:2D4693 Test Method for Low-Temperature Torque of Grease-Lubricated Wheel Bearings2.2 ANSI/AFBMA Standard:Standard 20-1987Radial Bearings of Ball,Cylindrical,Roller,and Spherical-Roller TypeMetric Designs(AF-BMA Code 20BCO2JO)32.3 ASTM Adjuncts:Standard ball bearings(set of 5 ball bearings)43.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 low-temperature torque,nthe torque in gcm re-quired to restrain the outer ring of a No.6204 size open ballbearing lubricated with the test grease while the inner ring isrotated at 1 6 0.05 r/min at the test temperature.3.1.2 running torque,nthe 15-s average value of thetorque after rotation for a specified period of time(60 min).3.1.3 starting torque,nthe maximum torque measured atthe start of rotation.4.Summary of Test Method4.1 A No.6204 open ball bearing is packed completely fullof the test grease and cleaned off flush with the sides.Thebearing remains stationary while ambient temperature is low-ered to the test temperature and held there for 2 h.At the endof this time,the inner ring of the ball bearing is rotated at 1 60.05 r/min while the restraining force on the outer ring ismeasured.4.2 Torque is determined by multiplying the restrainingforce by the radius of the bearing housing.Both starting torqueand torque after 60 min of rotation(running torque)aredetermined.5.Significance and Use5.1 This test method was developed using greases havingvery low torque characteristics at 54C(65F).Specifica-tions for greases of this type commonly require testing at thistemperature.Specifications for greases of other types canrequire testing at temperatures from 75 to 20C(100 to0F).1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.G0.05 on Functional Tests-Temperature.Current edition approved May 1,2011.Published May 2011.Originallyapproved in 1957.Last previous edition approved in 2007 as D147807.DOI:10.1520/D1478-11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from AFBMA(Anti-Friction Bearing Manufacturers Association),1101 Connecticut Avenue,N.W.,Suite 700,Washington,DC 200364303.4The ball bearing has been standardized by Subcommittee D02.G0.Availablefrom ASTM International Headquarters.Order Adjunct No.ADJD3336.Originaladjunct produced in 1984.*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 5.2 This test method has proved helpful in the selection ofgreases for low-powered mechanisms,such as instrumentbearings used in aerospace applications.The suitability of thistest method for other applications requiring different greases,speeds,and temperatures should be determined on an indi-vidual basis.5.3 Test Method D4693 may be better suited for applica-tions using larger bearings or greater loads.However,greaseshaving such characteristics that permit torque evaluations byeither this test method or Test Method D4693 will not give thesame values in the two