ASTM D1478-2011(2017)e1 Standard Test Method for Low-Temperature Torque of Ball Bearing Grease《球轴承滑脂低温扭矩的标准试验方法》.pdf

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1、Designation: D1478 11 (Reapproved 2017)1Standard 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 la

2、st 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or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1NOTEReference to withdrawn ADJD3336 was remov

3、ed editorially in June 2017.1. 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 20 C (0 F).1.1.1 Torque measurements are limited by the capacity ofthe

4、 torque-measuring equipment.NOTE 1When 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the original dynamometer scalelimited the torque capacity to approximately 30 000 gcm; the originaldynamometer scale is obsolete, however.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 approximately75 0

5、00 gcm.1.2 The values stated in SI units are to be regarded asstandard.1.2.1 ExceptionsThe values given in parentheses are forinformation only. The exception is torque values that are givenin cgs-metric units, which are universally used in greasespecifications.1.3 This standard does not purport to a

6、ddress 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、 7.2, 7.4, 8.7, and 8.11.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organiza

8、tion TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D4693 Test Method for Low-Temperature Torque of Grease-Lubricated Wheel Bearings2.2 ANSI/AFBMA Standard:Standard 20-1987 Radial Bearings of Ball, Cylindrical,Roller, and Spherical-Roller TypeMetric Designs (AF

9、-BMA Code 20BCO2JO)33. 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 rmin 6 0.05 rmin at the t

10、est 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

11、 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 at1 rmin 6 0.05 rmin while the restraining force on the outerring is

12、 measured.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 May 1, 2011. Published June 2017. Originallyapproved in

13、1957. Last previous edition approved in 2011 as D1478 11. DOI:10.1520/D1478-11R17E01.2For 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

14、page onthe ASTM website.3Available from AFBMA (Anti-Friction Bearing Manufacturers Association),1101 Connecticut Avenue, N.W., Suite 700, Washington, DC 200364303.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C

15、onshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade

16、 Organization Technical Barriers to Trade (TBT) Committee.14.2 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 develop

17、ed using greases havingvery low torque characteristics at 54 C (65 F). Specifica-tions for greases of this type commonly require testing at thistemperature. Specifications for greases of other types canrequire testing at temperatures from 75 C to 20 C(100 F to 0 F).5.2 This test method has proved he

18、lpful 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 ma

19、y 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 test methods (even when converted tothe same torque units) be

20、cause the apparatus and test bearingsare different.6. Apparatus6.1 Fig. 1 shows a suitable torque test apparatus assembly.It consists of the components described in 6.1.1 6.1.5.6.1.1 Low-Temperature BoxAny well-insulated box of atleast 0.03 m3(1 ft3) interior volume, in which the air tempera-ture ca

21、n be controlled and maintained within 0.5 C (1 F) ofthe test temperature. (WarningDirect impact on the testbearing by an air stream colder than the test temperature mustbe avoided to preclude erroneous results. Baffles should beused where necessary to prevent such direct impact. The drivemechanism c

22、an be mounted externally as shown in Fig. 2,orthe entire drive mechanism can be inserted directly into thebox. When the drive is mounted externally, the temperaturemeasured at a point on the surface of the test shaft between thetest bearing and wall of the box shall be not more than 0.5 C(1 F) above

23、 the test temperature.)6.1.2 Drive Assembly, as shown in Fig. 2, including drivemotor, gear reductor, and test shaft. The test shaft shall receivethe test bearing against a shoulder having a diameter smallerthan the inner race shoulder of the bearing. Use a spacerwasher of the same diameter and at l

24、east 1.6 mm (116 in.) thick,along with a test bearing lock nut, to clamp the inner ring of thetest bearing to the 1 rmin shaft.6.1.3 Housing (Cage)Bearing housing, load disk, loadring, clamp rod, and associated parts made in accordance withFig. 3.Adjust the mass of Part 2A(load disk) to be 454 g 6 3

25、g(1 lb). Alternatively, if Part 2B (load ring) is used, adjust themass of Part 2B to be 454 g 6 3 g (1 lb).6.1.4 Torque-Measuring EquipmentA calibrated dyna-mometer scale4having a range of approximately 0 kg to 10 kg,0 N to 100 N, or 0 lb to 25 lb, with a large face diameter(approximately 200 mm (8

26、in.), or larger) and a suitableconnecting cord of sufficient length (either braided metalliccable fitted with a ring or loop on each end or a 15 kg (35 lb)test string saturated with silicone oil).NOTE 2Substitution of other suitable torque-measuring equipment,such as a strain-gage load cell, is perm

27、itted.6.1.5 Spindle and Grease Cup, as shown in Fig. 4 and Fig.5, respectively.7. Materials7.1 Test BearingNo. 6204 size open ball bearing (Stan-dard 20-1987, AFBMA Code 20BCO2JO) containing eight7.9 mm (516 in.) balls, separated by a two-piece, pressed steelcage, and manufactured to ABEC-3 (Annular

28、 Bearing Engi-neering Committee) tolerances with the standard radial clear-ance of 0.021 mm to 0.028 mm (0.0008 in. to 0.0011 in.).57.2 Mineral Spirits, Reagent Grade. (WarningCombustible. Health Hazard.)7.3 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indica

29、ted, it is intended thatall reagents shall conform to the specifications of the commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.67.4 n-Heptane, reagent grade minimum purity. (WarningFlammable. Health Hazard.)4The sole source of supply of the

30、 Dynamometer Scale, QDS-25 previouslyknown to the committee was R. Chatillon note the average andmaximum running torque peaks. The average shall not exceed20 gcm (2.0 mNm), and no peak shall exceed 25 gcm(2.5 mNm). If torque values fall below these limits, thebearing is suitable for the grease torqu

31、e test. If torque valuesexceed these limits, the bearing should be recleaned andretested or discarded.FIG. 2 Drive (Top View)FIG. 3 Cage PartsD1478 11 (2017)138.3 Clean and dry a bearing that has been determined to beacceptable (8.2). Mount the bearing on a hand spindle (Fig. 4),fastening the inner

32、race by means of the washer and screw. Fillthe grease cup (Fig. 5) at least three-fourths full of the testgrease, using a clean steel spatula. Minimize the inclusion ofair.8.4 Force the bearing down into the grease and rotate thespindle-bearing assembly slowly, first in one direction and thenthe oth

33、er, to ensure that grease is worked into all parts of thebearing. When the bearing bottoms in the cup, slide thecylindrical cup ring off the plate and remove the spindle-bearing assembly from the cup. (The assembly may be pushedor pulled through the cup.)8.5 Remove the bearing from the spindle. Turn

34、 the bearingend-for-end, and refasten it on the spindle.8.6 Repack excess grease into the assembled grease cup.Again, force the bearing down into the grease, while rotatingthe spindle-bearing assembly slowly, first in one direction andthen the other, until the bearing bottoms.8.7 Slide the cup ring

35、off of the plate, and remove thespindle-bearing assembly from the cup ring. Scrape the excessgrease off flush with the sides of the bearing, filling any visiblevoids, and then remove the spindle. (WarningTake care notto rotate the bearing at any time after striking the grease flushand prior to the m

36、easurement of starting torque.)8.8 Insert the packed bearing into the test housing and fastenthe clamp cap over the bearing.8.9 With the low-temperature box precooled to the testtemperature, open the box and slide the test bearing andhousing over the end of the test shaft. Fasten it with the washera

37、nd nut tightly enough to prevent slippage.8.10 Attach the cord under the head of the screw on theperiphery of the housing. Rotate the test shaft until the slack inthe cord hanging from the hook on the dynamometer scaleabove is almost taken up.The screw on the periphery must thenbe at least 90 degree

38、s down from vertical. More than 90degrees is acceptable, provided that the cord does not slip offthe periphery of the housing (Fig. 1).NOTE 3Measurements can also be made from horizontal or otherpositions if the cord attaching point is at or beyond the point of tangencyof the cord while torque is be

39、ing measured. This will ensure a full 65 mm(2.56 in.) torque radius.8.11 Close the box, and recool it to the test temperature.Maintain this temperature within 60.5 C (1 F) for 2 h afterthe box has recovered to the test temperature. (WarningDuring this time the bearing must not be disturbed or the te

40、stwill be invalid.)8.11.1 It is desirable that excessive condensation of mois-ture from the air in the cold box be prevented, especially duringhumid weather. To this end and prior to the test, place shallowtrays containing a desiccant in the bottom of the low tempera-ture box.8.12 Check the torque c

41、ord to be sure it is free of ice and notstuck to the box.Asplit rubber stopper can be used to close thehole in the box wall, through which the cord runs, to keep thecord and passage free of ice from moisture-laden air. Removethe stopper before the run.FIG. 4 SpindleD1478 11 (2017)148.13 To determine

42、 starting torque, start the drive motor andobserve the dynamometer scale. Record the maximum readingand calculate the starting torque according to Section 9.8.14 Continue rotation of the test shaft for 60 min whilemaintaining the test temperature within 60.5 C (1 F). At theend of this time, observe

43、the dynamometer reading for a periodof 15 s, and record the average value and calculate the runningtorque according to Section 9.8.15 When running repeat tests, the bearing shall be re-cleaned (see 8.1) and packed with a fresh charge of grease (see8.3 and 8.4) between tests. Do not force out tested

44、grease witha fresh charge of grease.NOTE 4A pressure sprayer employing mineral spirits can be used tofacilitate the removal of grease from the bearing.9. Calculation and Report9.1 Depending on the dynamometer scale calibration, cal-culate and report starting and running torques in gcm to threesignif

45、icant figures using the appropriate equation, as follows:9.1.1 For a scale calibrated in grams:torque 5 6.50 3scale reading (1)9.1.2 For a scale calibrated in pounds:torque 5 2950 3scale reading (2)FIG. 5 Grease CupD1478 11 (2017)159.1.3 For a scale calibrated in Newtons:torque 5 663 3scale reading

46、(3)9.2 To convert torque in gcm to torque in mNm, multiplyby 0.0981 and round to three significant figures.10. Precision and Bias7,810.1 PrecisionThe precision of this test method was notobtained in accordance with currently accepted guidelines (forexample, Committee D02 Research Report RR:D02-1007,

47、Manual on Determining Precision Data forASTM Methods onPetroleum Products and Lubricants).10.1.1 Alternative A:10.1.1.1 Low-temperature torque results derived from coop-erative testing using this procedure show appreciable scatter. Ingeneral, the data were found to conform to Weibull probabilitydist

48、ributions, rather than the “normal” distributions aroundwhich ASTM statements of repeatability and reproducibilityare formulated. Weibull parameters such as Slope, L10, andL50 have been used to describe the test data.10.1.1.2 Precision may be judged from Fig. 6 and Fig. 7,Weibull plots for starting

49、and running torques, respectively,and from the calculated Weibull parameters in Table 1.Precision may also be judged from the range for the center50 % of the reported test results.10.1.1.3 Replicate testing is essential when using thisprocedure, since appreciable scatter in test results can beexpected.10.1.2 Alternative B:10.1.2.1 The following criteria should be used in judgingthe acceptability of results (95 % confidence). These calcula-tions are based on logarithmic data transformations.10.1.2.2 Repeatabili