1、MIL-B-17931EAMENDMENT 222 May 1995This1987, andMILITARY SPECIFICATIONBEARINGS, BALL, ANNULAR, FOR QUIET OPERATIONamendment forms a part of MIL-B-17931E, dated 27 Julyis approved for use by all Departments and Agencies ofthe Department of Defense.PAGE 4.* 2.2 Add under AFBMA:“Society of Automotive En
2、gineers (SAE)AMS 6444 - Steel Bars, Forgings, and Tubing 1.45Cr(0.98-1.10) (SAE 52100) Premium Aircraft-Quality, Consumable Electrode VaccumMelted.“PAGE 4* 3.2.1: Delete and substitute:“3.2.1. er and outer ring material. Material for innerand outer rings shall be chromium-alloy steel (type 52100)pro
3、duced by vacuum induction melt, vacuum arc remelt (VIM VAR) inaccordance with AMS 6444. Calcium alloy additions shall not beused for deoxidation or inclusion shape control. The ring billetmaterial shall be in accordance with the nonmetallic inclusionrating requirements of ASTM A 295. The steel micro
4、structureshall be uniform and spheroidized and shall meet the carbidenicrostructure requirements of ASTM A 295 (see Table VI).“*PAGE3.2.2, Sentence 2, Delete and“The ball billet material shall be5substitute:in accordance with the non-metallic inclusion rating requirements of ASTM A 295.”Insert befor
5、e sentence 4:“The steel microstructure shall be uniform and spheroidized andshall meet the carbide microstructure requirements of ASTM A 295(see Table VI).“AMSC NA 1 of 4 FSC 3110 -DISTRIBUTION STATEMENT A Approved for public release;distribution is unlimited.Provided by IHSNot for ResaleNo reproduc
6、tion or networking permitted without license from IHS-,-,-MIL-B-17931EAMENDMENT 23.3.2, Sentence 3: Delete and substitute:“The mean hardness of the balls shall be at least two Rockwell Cpoints greater than the mean hardness of the rings.“3.3.3, Line 2: Delete “300F“ and substitute “a minimum of250F”
7、.PAGE 11* TABLE I, Radial internal clearance min/max column forstandard part number M17931-G087: Delete “0.0020/0.0026“ andsubstitute “0.00124/0.0030”.TABLE I, OD max/min column for standard part number M17931-G088: Delete “11.4173/11.4173” and substitute “11.4173/11.1470”.TABLE I, Add footnote “2”
8、reference to width max column forstandard part number M17931-G087.TABLE I, Add footnote 2:“2/ Under 15-pound axial gage load, the unloaded side faceof the inner ring shall stick out .0110 -.0115 inches beyond theouter ring side face for both loading directions. Inner ringwidth variance to satisfy th
9、e stickout requirement is permitted.”PAGE 14* TABLE 111, Width max column for standard part numbersM17931-A004, M17931-A006 and M17931-A007: Delete “1.3260“ andsubstitute “1.3386“.PAGE 19* 3.4.5: Insert new sentence 4, “The installed cage shall notimpede relubrication of a bearing that requires relu
10、brication.Snap-in type cages shall be installed with the open side of thecage facing the marked side of the bearing.”PAGE 21* 3.7: Insert before sentence 1, “Die-stamps shall not beused for marking.“2Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MI
11、L-B-17931EAMENDMENT 2PAGE 23* TABLE VI, category, minor, add:“211 Ring material inclusions and microstructure do not meetrequirements (see 3.2.1).”“212 Ball material inclusions and microstructure do not meetrequirementsAdd new(see 3.2.2).”PAGEparagraph 6.4.6:2930.“6.4.6. Mean hardness. Mean hardness
12、 is the arithmetic meanof hardness values found in the required standardizing test ofeach lot reported to the nearest tenth:Mean hardness: R = (R1+R2+ . Rn)/nWhere RI, .Rn are the hardness valueslot. “PAGE 3230.1, Delete and substitute:of30.1 atigue life. Bearing fatigue lifen samples in thefor sing
13、lebearings shall be calculated in accordance with ANSI/AFBMAStandard 9. Bearing fatigue life for bearings in duplexarrangements shall be calculated in accordance with ANSIAFBMAStandard(a)(b)(c)9 with the following exceptions:Treat the duplex bearing as two individual single rowbearings.Account for a
14、xial and radial forces from all externaland internal loads, including centrifugal force,preload, shaft-to-bearing interference fit, anddifferential thermal expansion of the races and ballsas the bearing heats up to operating temperature.Use the Palmgren combined life expectancy formula toaccount for
15、 the reduced reliability of a two-bearingarrangement:3Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-B-17931EAMENDMENT 2bearings.Bearing life adjustment factors shall not be usedcalculation, unless specifically permitted by thespecification.“in
16、theequipment30.4, Last sentence, delete “tongs“ and substitute “tangs”PAGE 36TABLE XI, Housing bore diameter (inches) max column: Delete“5.5135” and substitute “5.5128”.PAGE 39TABLE XII, Add item: Standard part number “M17931-G056”,Navy code “212Z”.NOTE : The margins of this amendment are marked wit
17、h asterisks toindicate where changes (additions, modifications, corrections,deletions) from the previous issue were made. This was done as aconvenience only and the government assumes no liabilitywhatsoever for any inaccuracies in these notations. Bidders andcontractors are cautioned to evaluate the
18、 requirements of thisdocument based on the entire content irrespective of the marginalnotations and relationship to the last previous issue.Preparing activity:Navy - SH(Project 3110-N010)Custodians:Army - AVNavy - SHAir Force - 99Review activities:Army - ATAir Force - 84DLA - IS4Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
