1、Designation: D1478 18Standard 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 numb
2、er 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.1. Scope*1.1 This test method covers the determination of the ext
3、entto which a grease retards the rotation of a slow-speed ballbearing by measuring starting and running torques at lowtemperatures (below 18 C (0 F).1.1.1 Torque measurements are limited by the capacity ofthe torque-measuring equipment.1.1.2 This test method is not suitable for greases exhibitingtor
4、que values greater than 50 000 gcm at the selected testtemperature.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the original dynamometer scalelimited the torque capacity to approximately 30 000 gcm; the originaldynamometer scale is obsolete, however.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 coul
5、d extend the limit to approximately50 000 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 widely used in grease specifica-tions.1.3
6、 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Fo
7、r specific hazard and warning statements, see 6.1.1, 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
8、Recom-mendations issued by the World Trade Organization 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/ABMA Standard:ABMA20:2011 Radial Bearings of Ball, Cylindrical, Rolle
9、r,and Spherical RollerTypeMetric Designs (ABMACode20BCO2JO)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
10、isrotated at 1 rmin 6 0.05 rmin 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 bear
11、ing 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 at1 rmin 6 0.05 rmin while t
12、he restraining force on the outerring is measured.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.1This test method is under the jurisdiction of ASTM Committee D0
13、2 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.G0.05 on Functional Tests - Temperature.Current edition approved June 1, 2018. Published July 2018. Originally approvedin 1957. Last previous edition approved in 2017 as D1478 11 (2017)1. DOI:10.
14、1520/D1478-18.2For 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 fromABMA(American Bearing Manufactur
15、ersAssociation), 330 N.Wabash Ave., Ste. 2000, Chicago, IL 60611.*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 StatesThis international standard was developed in accordance w
16、ith internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15. Significance and Use5.1 This test me
17、thod was developed 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 73 C to 18 C(100 F to 0 F).5.2 This test meth
18、od 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
19、 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 test methods (even when converted tothe same
20、torque units) because 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
21、 tempera-ture can 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
22、drivemechanism can 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
23、0.5 C(1 F) above 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 d
24、iameter and at least 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)
25、 to be 454 g 6 3g(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(approxim
26、ately 200 mm (8 in.), or larger) and a suitableconnecting cord of sufficient length (for example, a braidedmetallic cable fitted with a ring or loop on each end, or a 15 kg(35 lb) nylon fishing line, or test string saturated with siliconeoil).NOTE 2Substitution of other suitable torque-measuring equ
27、ipment,such as a strain-gage load cell, is permitted.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(ABMA 20:2011, ABMA Code 20BCO2JO) containing eight7.9 mm (516 in.) balls, separated by a two-piece, pressed steelc
28、age, and manufactured to ABEC-3 (Annular 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 beus
29、ed in all tests. Unless otherwise indicated, 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 H
30、azard.)8. Procedure8.1 Wash the selected test bearing thoroughly in mineralspirits and rinse it in a beaker of n-heptane. Dry the bearing for4The sole source of supply of the Dynamometer Scale, QDS-25 previouslyknown to the committee was R. Chatillon note the average andmaximum running torque peaks.
31、 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 torque test. If torque valuesexceed these limits, the bearing should be recleaned andretested or discarded.8.3 Clean and dry a bear
32、ing that has been determined to beacceptable (8.2). Mount the bearing on a hand spindle (Fig. 4),fastening the inner race by means of the washer and screw. FillFIG. 2 Drive (Top View)FIG. 3 Cage PartsD1478 183the grease cup (Fig. 5) at least three-fourths full of the testgrease, using a clean steel
33、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 other, to ensure that grease is worked into all parts of thebearing. When the bearing bottoms in the cup, slide thecylindrical cup ring o
34、ff 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 the bearingend-for-end, and refasten it on the spindle.8.6 Repack excess grease into the assembled grease cup.Again, force the bearin
35、g 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 off of the plate, and remove thespindle-bearing assembly from the cup ring. Scrape the excessgrease off flush with the sides of the be
36、aring, 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 measurement of starting torque.)8.8 Insert the packed bearing into the test housing and fastenthe clamp cap over the bearing.8.9 With t
37、he 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 washerand nut tightly enough to prevent slippage.8.10 Attach the cord under the head of the screw on theperiphery of the housing. Rotate the
38、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 degrees down from vertical. More than 90degrees is acceptable, provided that the cord does not slip offthe periphery of the housing (Fig. 1)
39、.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 being 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
40、 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 testwill be invalid.)8.11.1 It is desirable that excessive condensation of mois-ture from the air in the cold box be prevented, especial
41、ly 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 cord 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 w
42、hich the cord runs, to keep thecord and passage free of ice from moisture-laden air. Removethe stopper before the run.8.13 To determine starting torque, start the drive motor andobserve the dynamometer scale. Record the maximum readingand calculate the starting torque according to Section 9.FIG. 4 S
43、pindleD1478 1848.14 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 the dynamometer reading for a periodof 15 s, and record the average value and calculate the runningtorque according to Section 9.8.15 When run
44、ning 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 grease witha fresh charge of grease.NOTE 4A pressure sprayer employing mineral spirits can be used tofacilitate the removal of grease from the
45、 bearing.9. Calculation and Report9.1 Depending on the dynamometer scale calibration, cal-culate and report starting and running torques in gcm to threesignificant 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 sca
46、le calibrated in pounds:torque 5 2950 3scale reading (2)9.1.3 For a scale calibrated in Newtons:FIG. 5 Grease CupD1478 185torque 5 663 3scale reading (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
47、precision of this test method was notobtained in accordance with currently accepted guidelines (forexample, Committee D02 Research Report RR:D02-1007,Manual on Determining Precision Data forASTM Methods onPetroleum Products and Lubricants).10.1.1 Alternative A:10.1.1.1 Low-temperature torque results
48、 derived from coop-erative testing using this procedure show appreciable scatter. Ingeneral, the data were found to conform to Weibull probabilitydistributions, rather than the “normal” distributions aroundwhich ASTM statements of repeatability and reproducibilityare formulated. Weibull parameters s
49、uch 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 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
