MIL-B-17931E.pdf

NIL-B-17931E

27 JulY’1987

SUPERSEDING

BEARINGS,

This specification is

NIL-B-i7931D(sHIPs) 15 Aprii 1975 (See 6.7)

NILITARY SPECIFICATION

BALL, ANNULAR, FOR QUIET OPERATION

acmroved for use bv all Deoarcments and Azencies., of the Department of the Defense.

1. SCOPE

1.1 =. This specification covers annular ball bearings, with industry bore codes 00 through 22, and 32 for use in quiet operating (low vibration) machinery.

1.2 Classification. Ball bearings shall be identified“by the standard part numbers designated in 1.2.1, as specified (see 6.2.1) Bearings shall be Of the types and classes defined in 1.2.2 as listed for each standard part number.

1.2.1 Ball bearing part numbers

shall be as follows:

17931 Xxxx

I I

I

Example: N17931-G064

Standard part numbers for ball bearings

Bearing part number (see 3.4)

Specification number - does not include revision letter or accivity symbol.

M prefix - an item defined by inch-pound (US) units

Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to:

Commander, Naval Se+ Systems Command, SEA S5Z3, Department of the Navy, Washington, DC 20362-5101 by using the self-addressed StandardizationDocument Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter

AMSC NjA FSC 3110 DISTRIBUTION STATEMENT A Approved for public release; distributionunlimited

Downloaded from http://www.everyspec.com

1 NIL-B-17931E

1.2.2 Ball bearing types and classes The ball bearings specified herein (see 3.4) are of the following types and classes:

Type 111 - Single row, radial, nonloading groove, both rings same width, metric.

I Class 1 - Open.

Class 2 - Single

I Class 3 - Double

I Class 1 - Single Class 8 - Double shield (suffix Z) shield (suffix 22) contact seal (suffix S) contact seal (suffix SS)

Type 120 - Single row, radial, nonloading groove, both rings same width, sealed (cartridgetype without grease plug), metric bore and outside diameter (od), inch width. Type class class

Type 131 -

Class Class

Type 133 -

C18SS

Type 134 -class Class

120 bearings have prefix S3

1 - Noncontact or iabyrinth seals.

2 - Synthetic contact seals.

Single row, counterbore [primarily radial), contact angle 8 degrees 30 minutes - 10 degrees 15 minutes Self-contained, both rings same width, metric.

1 - Single bearing (suffix R).

2 - Duplex pair (suffix RD), faces ground for universal mounting, that is, face-to-face (RDF), back-to-back (RDB), or tandem (RDT)

Single row, angular contact (contact angle 25 degrees or less), self-contained,both rings same width, metric.

Angular contact bearings have prefix 7.

2 - Duplex pair (suffix D), faces ground for universal mounting, that is, face-to=faie”(DF), back-to-back (DE), or tandem (DT).

Single row, angular’contact [contact angle greater than 25 degrees), self-contained,both rings same width, metric.

Angular contact bearings have prefix 7.

1.’- Single bearing.

2 - Duplex pair (suffix O), faces ground f6r universal mounting, that is, face-to-face (DF), back-co-back (DB)i or tandem (DT). Bearings having suffix DF or DB are made fo~.that mounting only

Pill.-B-l7!l3ll;

1,3 Navy COdC. The!Navy code consists of a three-di.gichfisicbearing Ilumbcrh,ithprcfi.xand/or suffi.sss specified in 1.2.2. The basic bearing number identifies the external boundary dimensions. The first digit of the basic bearing Ilumbcridentifies the bearing series (or weight) as follows:

1 Extra-light (for all types except 120) 2 Light (for all types except 120) 3 Nedium (for all types except 120) 4 Heavy (for all types except 120) 5 Light (for type 120 bearings only) 6 Nedium (for type 120 bearings only)

Tbe second and third digits of the basic bearing number are the industry bore code. When multiplied by 5, these digits give the bearing bore diameter in millimeters for bore codes 04 and greater (this rule does not apply for bore codes 00 through 03).

2. APPLICABLE DDCUNENTS

2.1 Government documents.

2.1.1 Specifications and standards The following specificationsand standards form a part of this specification to the extent specified herein.

Unless otherwise specified, the issues of these documents shall be those listed in the issue of the Department of Defense Index of Specificationsand Standards (DoDISS) and supplement thereto, cited in the solicitation.

SPECIFICATIONS

FEDERAL

FF-B-171 -

NILITARY

NIL-B-197 -

N1L-B-1083 -

NIL-L-60B5 -

MIL-L-17331 -

DOD-G-24508 -

STANDARD

NILITARY

MIL-STD-105 -

Bearings, Ball, Annular (General Purpose)

Bearings, Antifriction; Associated Parts and Subassemblies; Preparation for Delivery of.

Balls, Bearing, Ferrous and Nonferrous (For Use in Bearings and Valves).

Lubricating Oil, Instrument,Aircraft, LOW Volatility.

Lubricating Oil, Steam Turbine and Gear, Moderate Service.

Grease, High Performance,Multi-Purpose. (Metric)

Sampling Procedures and Tables for Inspection by Attributes.

(Copiesof specifications and standards required by contractors in connectionwith specific acquisition functions should be obtained from the contracting activity or as directed by the contracting activity.)

1.2 (]L!I+,!-,,!lb!icnLiotbs Tll,:[01Iowil)gclOctmlcIILsfol-w3 )?arLof 1.1,is_—— —_— s,)ecifictlLio!lLo LilIJ(!.xLcIILSpccificd hc?l-eill UllicssOtllcl-wi.c Sp$:cifid, Llrc issues 0[ L)lc!documents which arc ~o~ adOpLcd Shal1 be Cllosc]isted in the issue of the DoDISS specified in C1l.issolicitation. Unless otherwise spccificd, the issues of documents not listed in the DoDISS shal1 be the issue of Lhe nongovcl-n-ment documents wkich is currenc on che date of rhe so]jcitation.

ANERIcAN SOCIETY FOR TESTING AND MATF.RIALS (AS’171) A 295 -

I E18-

1 E 112 -

Standard Specification for Hig~-Carbon Ball and Roller Bearing Steel (DoD adopted) Standard Test Nethods for Rockwell Hardness and Rockwel1 Superficial Hardness of Netallic Materials. (DoD adopted) Stal]dardMethods for DeterminingAverage Grain Size, (DoD adopted)

(Applicationfor copies should be addressed to the American Sociecy for Testing and Naterials, 1916 Race Street, Philadelphia,PA 19103.)

ANTI-FRICTIONBEARING NANUFACTURERS ASSOCIATION (AFBMA)

Standard 10 - Netal Balls Standard 13 - Rolling Bearing Vibration and Noise (Nethodsof

Measuring) Standard 20 - Metric Ball and Roller

Boundary Plans

(Applicationfor copies should be addressed to ~n,lufacturcrsAss0ciati0n3 1101 Connecticut Avcriue, DC 20036.)

Bearings Conforming to Basic the Anti-FrictionBearing N.W., Suite 700, Washington, (Non~overnmentstaadards and other publications are normally avai]able from the ~rganizationswhich prepare or L,bichdistribute the documents These document.s also may be available in or through librariesor other informational services )

2.3 Order of precedence. In the event of a conflict between the text of this specificationand the references cited herein, the text of this specifi-cation shall take precedence. Nothing in this specification,however, shall supersede applicable laws and regulations unless specific exemption has been obtained.

7 Rrn[lll?cklrwrc

3.1 General Bearings furnished under this specificationshall be in accordance with FF-B-171 and as specified herein.

3.2 Naterials. Naterials for the bearing component parts furnished under this specificationshall meet the requirementsof 3.2.1 through 3.2.4

3.2.1 Inner and outer ring material Bearing rings shall be made of 52100 chromium-alloysteel. Tbe steel shall be produced by the electric furnace process and vacuum-carbon-deoxidizedor any other steel making process chat produces steel in accordancewith ASTM A 295. The finished ring material shall not exceed the inclusion rating specified for the billet material in ASTN A 295.

Grain size shall be determined in accordance with ASTN E 112.

:l!l,-1)-17°:)}1’.

3.2.2 ~_~all m:ltcrial. 1331IS s),al) ))Ctmr3dcof 52100 cllrcm,itm,-ol10? SL,:SI The steel sl,al1 be produced by che clectric furnace process and x$:lc\lut>~-c(ll-\><>,,-deoxidized or any o~hcr s~eel making process that produces steel in accordance with AsTN A ‘295. The finished ba11 material shal1 not exceed the inclusion rating specified for the billet material in ASTM A 29S Grain size shal1 be dctermiaed in accordance with ASTN E 112.

3.2.3 Shield, seal, and cage material Shields, seals and cages of ferrous.

nonferrous or nonmetallicmaterials are acceptable. Naterialsshall be resistant to deteriorationby lubricant,prescrvacive, hydraulic fluid, solvents or other substances and chemicals that can be expected to come into contact with CIICbearing, and shall cause no deterioration of the same. Bearings with nonmetallic cages shall meet the same inspection,qualification and performance requirementsof FF-B-171 as bearings with metallic cages. Naterials for cages shaIl be of the same composition as furnished on the sample bearings submitted [or FF-B-171 qualificationinspection. Naterials shaLl withstal~dcontinuous operation to 23o degrees Fahrenheit (“F)

3.2.4 Recovered materials Unless otherwise specified herein, al1 equip-ment, material, and articles incorporated in the products covered by this speci-fication shall be new and may be fabricated using materials produced from recovered materials to the maximum extent practicable without jeopardizing Llle intendeduse. The term “recoveredmaterials” means materials which have been collected or recovered from solid waste and reprocessed to become a source of raw materials, as opposed to virgin raw materials None of the above shall be interpretedto mean that the use of used or rebuilt products is allowed under this specification.

3.3 Heat treatment. The heat treatment processes shall be such chat the finished rings and balls meet the requirements of 3.3.1 through 3.3.3.

3.3.1 Hardness of rings. Hardness of rings shall be not less than Rockwell C 58 as determined in accordance with ASTN E 18. Hardness of rings shall not vary more than three points on the Rockwell C scale on any one ring.

3.3.2 Hardness of balls. Hardness of balls shall be as specified in M1L-B-1083 for composition 1 materials. Case hardened or work hardened balls are not acceptable. Balls shall be matched with rings so that the hardness of any ball shall be at least 2 Rockwell C points greater than the hardness of the rings

3.3.3 Stability. Heat treatment shall be such that size change shall not exceed the following percentages after exposure to 300”F for 2500 hours:

Rings: 0.010 percent Balls: 0.020 percent

3.4 Construction. Bearings shall comply with the requirementsof tables 1, 11 or III for the standard part number specified (see 1.2 and 6.2.1). Unless otherwise specified herein, the details of the component parts shall be optional with the contractor. Bearings shall be manufactured using new, unused component parts only.

Standar part number N17931-

GOO1

GO02

GO03

Go04

Go05

GO06

GO07

GO08

GO09

GO1O

GOII

G012

G013

GO14

G015 rype/clas jsee 1.2)

111/1

111/8

111/1

111/2

111/1

111/2

111/1

111/2

111/3

111/8

111/2 ill/8

111/1

111/2

111/8

NII,-11-17,J31E

TABLE 1. Type 111 bcariugs

Navy code

‘see1.3

00ss

301Z

302Z

203Z

03ZZ

03ss

303Z

03ss

204Z

34ss

See footnote at end of table, Dimensions (inches)

Bore maxfmin

0.3937 0.3935

0.3937 0.3935

0.4724 0.4722

0.4724 0.4722

0.5906 0.5904

0.5906 0.5904

0.6693 0.6691

0.6693 0.6691

0.6693 0.6691

3.6693 3.6691

3.6693 m

).6693 1.6691

).7874 ).7872

).7874 ).7872

).7874 ).7872

Od maxfmin

1.1811 1.1809

1.1811 1.1809

1.1024 1.1022

1.4567 1,4565

1.3780 1.3778

1.6535 i.6533

1.5748 1.5746

1.5748 1.5746

1.5748 1.5746

1.5748 1.5746

1.8504 1.8502

1.8504 1.8502

1.8504 1.8503

1.8504 1.8503

1.8504 1.8503

Width max

(see 3.L.7

0.3543

0.3543

0.3150

0.4724

0.4331

0.5118

0.4724

0.4724

0.4724

0.4724

0.5512

0.5512

0.5512

0.5512

0.5512

Radial nternal :learanc~ minfmax

0.0003 0.0006

0.0003 0.0006

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0004 0.0007

0.0005 0.0008

0.0005 3.0008

M 3.0008

Lubri-cant

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

Standam pare lnumber N17931-

G016

GO17

G018

G019

G020

G021

G022

G023

G024

G025

G026

G027

G028

G029

G030

‘ype/class see 1.2)

111/1

111/2

111/1

111/2

111/1

111/2

111/8

111/1

111/2

111/1

111/2

111/3

111/8

111/2

111/1 il[l,-11-17,.l:llE

TAB1,F:I ~:l)e11I bcaring~. - Continued

Navy code

:see 1.3)

304Z

205Z

305Z

305ss

206Z

306Z

306ZZ

306SS

406Z

See footnoteat end of table

Dimensions (inches)

Bore nax/min

0.7874 0.7,872

0.7874 0.7872

0.9843 0.9841

0.9843 0.9841

0.9843 0.9841

0.9843 0.9841

0.9843 0.9841

1.1811 1.1809

1.1811 1.1809

1.1811 1.1809

1.1811 1.1.809

1.1811 1.1809

1.1811 1.1809

1.1811 1.1809

1.3780 1.3778

Od maxfmin

2.0472 2.0470

2.0472 2.0470

2.0472 2.0470

2.0472 2.0470

2.44o9 2.44o7

2.4409 2.4407

2.4409 2.4407

2.4409 2.4407

2.4409 2.4407

2.8346 2.8344

2.8346 2.8344

2.8346 2.8344

2.8346 2.6344

3.5433 3.5431

2.8366 2.8344

Width max

(see 3.4.7)

0.5906

0.5906

0.5906

0.5906

0.6693

0.6693

0.6693

0.6299

0.6299

0.7.480

0,7h80

0.7480

0.7480

0.9055

0.6693

Radial nternal learance min/max m 0.0008

0.0005 0.0008

0.0005 0.0008

0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0008

.ubri-cant

G

G

G

G

G

G

G

G

G

G

G

G

G

G

Standard lnumber )117931-

G031

G032

G033

G034

G035

G036

G037

G038

G039

G040

G041

G042

G043

G044

G045

‘ypejclass see 1.2)

111/1

111/2

111/3

111/8

111/1

111/1

111/2

111/8

111/1

111/1

111/2

111/7

111/8

111/1

111/1 rlll)-ll-li~l:ilK

I’AIJI,.!I Type 111 bearin=. - Continued-.

Navy code

:see 1.3, 307Z

I07ZZ

)07ss

308Z

109ss

309Z

309s

309ss

See footnote at end of table.

Dimensions (inches)

Bore na.x/min

1.3780 1.3778

1.3780 1.3778

1.3780 1.3778

1.3780 1.3778

1.5748 1.5746

1.5746

1.5748 1.5746

1.7717 1.7715

1,7717 1.7715

1.7717 1.7715

1.7717 1.7715

1.7717 1.7715

1.7717 1.7715

1.9683

1.9685 1.9683

Od mox/min

3.1496 3.1L94

3.1496 3.lf+94

3.1496 3.1494

3.1496 3.1494

3.1496 3.1494

3.5433 3.5431

3.5433 3.5431

2.9528 2.9526

3.3463

3.9370 3.9368

3.9370 3.9368

3.9370 3.9368

3.9368

3.5431

4.3307 6.3305

Width max

(see 3.4.7)

0.8268

0.8268

0.8268

O.826L3

O.7087

0.9055

0.9055

0.6299

0.7480

0.9843

0.9843

0.9843

0.9843

0.7874

1.0630

Radial nternal learance min/max

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

Lubri-cant

G

G

G

G

G

G

G

G

G

G

G

G

G

G

I I

I

I

I I

I

I I

I

I

I I I

I

I

Standard part number M17931-

G046

G047

G048

G049

G050

G051

G052

G053

G054

G055

G056

G057

G058

G059

G060 ypefclnss see 1.2)

111/2

111/3

111/8

111/2

111/1

111/1

111/2

111/3

111/8

111/1

111/2

111/1

111/2

111/3

111/3

!III,-11-17’J31F.

‘TABLE1. ~ype 111 beorings - Continued

Navy code see 1.3)

31OZ

!1OZZ

!10ss

41OZ

311Z

Illzz

Illss

212Z

312Z

)12ZZ

?13ZZ

I)imensions(inches)

See footnote at end of table.

tax/rein

1.9685 1.9683

~.9685 1.9683

1.9685 1.9683

1.9685 ~.9683

2.1654 ?.1652

2.1654 2.1652

2.1654 2.1652

2.1654 2.1652

2.1654 2.1652

2.3622 2.3620

2.3622 2.3620

2.3622 2.3620

2.3622 2.3620

2.3622 2.3620

2.5591 2.5589

Od maxlmin

4.3307 4.3305

4.3307 4.3305 fk.3307 4.3305

5.1179

3.9368

4.7244 .4.7242

4.7244 4.7242

4.7244 4.7242

L.7244 k.7242

4.3307 4.3305

4.3307 4.3305

5.1181 5.1179

5.1181 5.1179

5.1181 5.1179

4.724L 4.7242

Width max

,see3.4.7)

1.0630

1.0630

1.0630

1.2205

0.8268

1.1417

1.1417

1.1417

1.1417

0.8661

0.8661

1.2205

1.2205

1.2205

0.9055 iadial nternal learance nin/max

0.0005 D.0009

0.0005 0.0009

0.0005 0.0009

0.0005 0.0009

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

,ubu.i-cant

G

G

G

G

G

G

G

G

G

G

G

G

G

G

G

TABLE I Type 111 bcarill~s - COnti!iucd—

Standar part I)umber )117931-

G061

G062

G063

G06L

G065

G066

G067

G06L3

G069

G070

G071

G072

G073

G07&

G075

‘ype/clOs see 1.2)

111/1

111/2

111/1

111/1

111/2

111/3

111/1

111/1

111/2

111/2

111/3

111/1

111/2

111/1

111/3

Navy code

:see 1.1

14ZZ

315Z

See footnote at end of table

Dimensions (inches)

Eorc max/min

2.5591 2.5589

2.5591 2..5589

2.5591 2.5589

2.7559 2.7557

2.7559 2.7557

2.7559 2.7557

2.9528 2.9526

2.9528 2.9526

?.9528 2.9526

2.9528 ?.9526

3.1496 1.1493

3.1496 ~.1493

1.1/+96 ).1493

).3465 \.3462

1.3465 ).3462

Od max/min

5.5118 5.5116

5.5118 5.5116

5.5118 5.5116

5.9055 5.9053

5.9055 5.9053

5.9053

5.1181 5.1179

6.2992 6.2990

W 6.2990

6.29!32 6.299o

S.5118 5.S116

6.6929 6.6926

6.6929 6.6926

5.9055 5.9053

5.9055 5.9053

Width max

[see 3.4.7

1.2992

1.2992

1.2992

1.3780

1,3780

1.3780

0.9843

1,4567

1.4567

1.4567

1.0236

1.5354

1.5354

1.1024

1.1024

Radial nternal .learanc( min/max

0.0007 0.0011

0.0007 0.0011

Loose

0.0008 0.0012

0.0008 0.0012

0.0008 0.0012

0.0008 0.0012

0.0012 m 0.0012

E 0.0012

0.0008 0.0012

0.0008 0.0012

0.0012

0.0009 0.0014

0.0009 0.0014

7Lubri-cant

G

G

L

G

G

G

G

G

G

L

G

G

G

G

G i

Standan number M17931-

G076

G077

G078

G079

G080

G081

G082

G083

G084

G085

G086

G087

G088

‘ype/clas:

see 1.2)

111/1

111/2

111/1

111/1

111/2

111/2

111/2

111/1

111/1

111/1

111/1

111/1

111/1

N114-1)-17931E

TABLE 1. Type 111 bearings - Continued

Navy code see 1.3

317Z

319Z

220Z

320Z

Dimensions (inches)

Bore max/min

3.3465 3.3462

3.3465 3.3462

3.5433 3.5430

3.74o2 3.7399

3.7402 3.7399

3.9370 3.9367

3.9370 3.9367

3.9370 3.9367

4,1339 4.1336

4.3307 4.3304

4.3307 m

4.3307 &.3304

6.29’32 6.2988

Od max/min

7.0866 7.0863

7.0866 7.0663

7,4603 7.4800

7.8737

7.674o 7.8737

7.0866 7.0863

W 8.4643

6.4646 6.4643

W 6.8580

7.674o 7.6737

9.4488 9.L485

9.4L86 9.4L85

11.4173 11.4173

Width max

(see 3.4.7;

1.6142

1.6142

1.6929

1.7717

1.7717

1.3386

1.8504

1.6504

1.9291

1.4961

1.9665

1.9685

1.8898

Radial nternal learance min/max

0.0009 0.0014

0.0009 0.0014

0.0009 0.0014

0.0009 0.0014

0.0014

0.0009 0.0014

0.0009 0.0014

0.0018 0.0023

0.0011 0.0016

0.0011 0.0016

0.0011 0.0016

0.0020 0.0026

0.0013 0.0021

,ubri-canr.

G

G

G

“G

G

G

G

G

G

G

G

G

G

‘ L means preservationflubricant shall be oil in accordancewith MIL-L-6085 G means lubricant shall be grease in accordance with DOD-G-24506.

Stal!dard number N17931-

Cool

CO02

CO03

CO04

coos

CO06

CO07

CO08

CO09

Colo

Coil

C012

C013

C014

Type/ class (see 1.2)

1?0/2

1?0/2

120/2

1?0/1

120/1

120/2 l~ofl l~o/2

120/2

120/2

120/1’

120/1

[20/1 i20/1

Navy code [see 1.3)

S3502

S3503

S3504

S3604

S3505

S3605

S3506

S3606

S3507

S3607

S3607

S3608

S3509

S3609

Dimensions (inches)

Bore maxfmin

0.5906 0.5904

0.6693 0.6691

0.7874 0.7B72

0.7874 0.7872

0.9843 0.9841

0.9843 0.9841

1.1811 1.1809

1,1811 1.1809

1.3780 1.3778

1.3780 1.3778

1.3780 1.3778

1.5748 1.5746

1.7717 1.7715

1.7717 1.7715

I See footnotes at end of table.

Od maxfmin

1.3780 1.3778

1.5748 1.5746

1.8504 1,8502

2.0472 2.0470

2.0472 ?.0470

2.4409 2!.4407

2,L409 2.4407

2.8346 2.83f+4

2.8346 2.8344

3.1496 3.1494

3.1496 3.1494

3.5423 3.5431

3.3463

3.9370 3.9368

\Jidtl] max

~see3.4.7’

0.6250

0.6875

0.8125

0.8750

0.8125

1,0000

0.937s

1.1875

1.0625

1.3750

1.3750

1.4375

1.1875

1.5625

Radial nternal learance min/max

0.0004 0.0007

0.0004 0.0007

0.0005 0.0008

0.0008 m 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0008

0.0005 0.0009

0.0005 0.0009 ubri-cant

G

G

G

G

G

G

G

G

G

G

G

G

G

I I I

I I

I

Standard part number N17931-

C015

C016

C017

C018

C019

C020

C021

C022

Type/ class (see 1.2)

120/2

120/21

120/1

120/2

120/2

120/1

120/1

120/2

I’1ll.-I)-)7’)3II:

TAIJ1.EII 1>Y2 1’20bcal-in~. - Cot)cinucd

Navy code (see 1.3)

S361O

S361O

S3611

S3612

S3613

S3614

S3615

S3618

Dimensions (inches)

Bore lax/rein

1.9685 1.9683

1.9685 1.9683

2.1654 2.1652

2.3622 2.3620

2.5591 2.5589

2.7559 2.7557

2.9528 2.9526

3.5433 3,5430

Od max/min

4.3307 4.3305

4.3307 4.3305

4.7244 4.7262

5.1179

5.5118 5.5116

5.9055 5.9053 m 6.2990

7.4803 7.4800

Uidch max

(see 3.4.7)

1.7500

1.7500

1.9375

2,1250

2.3125

2.5000

2.6875

2.8750

Radial internal clearance min/max

0.0005 0.0009

0.0005 0.0009

0.0007 0.0011

0.0007 0.0011

0.0007 0.0011

0.0008 0.0012

0.0008 0.0012

0.0009 0.0014

1 G means lubricant shall be grease in accordance with 00D-G-24508.

Lubri-cant

G

G

G

G

G

G

G

G

2 One seal removed.

NII,-11-17931E

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MIL-B- 7931E

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)[ll.-IJ-I793IK

3.4.1 ~pcs 111 and 120. Conscl-ucciousl!al1 be in accordancewith FF-B-171 and as specified herein. Bearings shal1 confoxm to the requirements of tables 1 and 11.

3.4.2 ~ye 131, class 1; type 133. class 1: and type 134, ClaSS 1. Types 131, 133 and 134 shall support thrust loads illone direction in combination with radial loads. These types shal1 have one raceway shoulder of the outer ring cut away almost to the bottom of its raceway in such a manner as to permit side assembly of the inner ring and balls into the outer ring without damage to the component parts, yet provide retention to .s11 parts in proper operating position during normal handling operations These types, when manufactured for mounting as single bearings, shall be termed as class 1. Inner rings of these types shal1 have equal height raceway shoulders or have the raceway shoulder cm the non-thrust side cut away in a manner similar to that employed cm the outer ring, provided that the bearings are self-contained in handling operations These types shal1 have a nominal inner ring raceway cross-sectional radius not larger than 52 percent of the ball diameter and a nominal outer ring raceway cross-sectional radius not larger than 53 percent of the ball diameter. Bearings shall conform to the requirementsof table 111.

3,4.2.1 Type 134, class 1. Flanufacturerspecified unmounted nominal contact angles shall be greater than 25 degrees to a maximum of 45 degrees.

Radial internal clearance shall not be specified.

3.4.3 Types 131, class 2; type 133, class 2; and type 134, class 2. The constructionof individualbearings of the duplex pairs shall conform to 3.4.2 and shall conform to che requirements of table III. Except for DB pairs (see 3.4.7), the bearing ring side faces shall be universal ground for the specified internal condition (see 3.4.8). The pairs shall be matched by che bearing manufacturer and the matched pairs shall be packaged together.

3.4.4 Balls. Balls for all type and class bearings shall be in accordance with MIL-B-1083 or AFBMA Standard 10, and aa specified herein. 8alls shall be grade 10 or better Balls used in the same bearing shall be selected from the same unit container.

3.4.5 g. Ball bearings shall have cages for spacing the balls in their proper relationshipwithin the bearings Cages shal1 be designed rindconstructed so as that not to impede the primary function of the bearing. The cage shall admit the lubricant freely to the functional surfaces (see 6.6.1), of the bearing.

3.4.6 Shields and seals. Shields and seals, when utilized, shall not affect the dimensional tolerances specified herein. Contact seals (see 6.4.2) shall not inhibit the free rotation of che bearing rings

3.4.7 Metrology. Bearings shal1 conform to the metrology requirements specified in tables I, II and III. Width tolerances of single bearings shall be plus O, minus 0.002 inch. For duplex bearings, the total width tolerance of inner and outer rings shall be plus O, minus O.01O inch. Subsequent to establishing the bearing internal condition (see 3.4.8), DB pair outer ring non-thrust faces shall be ground to a total width tolerance of minus O.008 to minus 0.010 inch.

Additional metrology requirements, such as ring and raceway runouts and paral-lelism, shall comply with AF8MA Standard 20 - tolerance class ABEC-7.

NII1-11-17’J311:

3.4.8 Negative stickouc or prelOad of duplex pairs. Bearings c.anrarming to types 131, class 2; type 133, class 2; and type 134, class 2 shall be manufactured to the limits of negative stickout (see 6.4.3) stated in inches or axial preload (see 6.4.4) stated in pounds listed in table III. For negative stickout duplex pairs, under the minimum practicable thrust gauging load used to establish free end play, the inner and outer ring side faces of individual bearings shall lie in parallel planes within the limits specified in table 111 far negative stickout For preloaded duplex pairs, a clamping force equal to the preload value of table III is required to bring the inner and outer ring side

3.5 in tables faces into flush contact.

Vibration. Bearings shall meet the vibration requirements specified

IV and V when tested as specified in 4.5.1.

TABLE IV. Vibration limits for individualbearings

LOW Niddle High Industry band band band bore code (anderons) (andercms) (anderons)

00 16 12 10 01 16 12 10 02 20 16 10 03 20 16 16 04 20 16 16 05 24 17 16 06 24 18 16 07 24 19 20 08 24 20 20 09 31 20 21 10 32 21 22 11 32 22 23 12 32 23 26 13 32 23 24 14 38 24 25 15 40 25 26 16 &o 26 27 17 40 26 28 18 40 27 29 19 40 28 30 20 40 29 31 21 49 30 32 22 50 30 33 24 50 31 34 26 57 32 36 32 68 40 40

TABLE V

tl114-l\-17’.13111

Vibratiotllimits for all bcarillgs(lot average~.

F Industry bore code

Low band

(anderons)

Niddle band

(anderons)

High band anderons)

3.6 Lubricant. Lubricant shall be as specified in tables 1, II or III.

Grease lubricatedbearings shall be preserved and prelubricatedwith grease in accordance with DOD-G-24~08. Oil lubricated bearings shall be preserved with oil in accordancewith MIL-L-6085. When grease is specified, tbe bearing void (the airspace contained between the inner and outer ring of the assembled bearing) shall be 30 to 50 percent filled.

3.7 Marking. Each bearing”shall be permanently marked with the following:

(a)

(b)

(c)

(d)

(e) (f]

The complete standard part number (ace 1.2), manufacturer’s name or symbol and complete bearing number, where space is available.

A serial number marked on the outer ring face or back, For duplex pairs, use the same serial number for each bearing, designating one bearing as XXXA and tbe other as XXXB.

An indication of direction of thrust load for all classes of types 131, 133 and 134.

The high point of radial runout On both inner and outer rings of duplex pairs Design preload (in.pounda)for all duplex pairs.

The symbol “NT4” on the outer ring.

1111,-IJ-17Y31E

3.8 A~licatiou I-equiremctlcsEquipment dcsigners and manufactucers shall comply with the appendix of this specification, to the extent specified therein

3.9 Interchangeability. All complete bearings having the same standard part number shall be functionally and dimensionally interchangeable.

3.10 Workmanship. Bearing functional and nonfunctional surfaces (see

6.4.1 and 6.4.5) shall be free of contamination from foreign particle debris, rust, and dirt. Additionally, all functional surfaces shall be free from mechanical and physical damage which would be detrimental to bearing performance.

Such damage would include but not be limited to tool marks, grinding scratches, pits, indentations,and cracks visible to the unaided eye,

4. QUALITY AsSURANCE PROVISIONS

4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchase order, the contractor is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified in the contract or purchase order, the contractor may use his own or any other facilities suitable for the performance of the inspection requirements specified herein, unless disapproved by the Government. The Government reserves the right to perform any of the inspections set forth in the specificationwhere such inspections are deemed necessary to sssure supplies and services conform to pre-scribed requirements

4.1.1 Responsibility for compliance. All items must meet all requirements of sections 3 and 5. The inspection set forth in this specification shall become a part of the contractor’s overall inspection system or quality program. The absence of any inspection requirements in the specification shall not relieve the contractor of the responsibility of assuring that all products or supplies submitted co tbe Government for acceptance comply with all requirementsof the contract. Sampling in quality conf.armsncedoes not authorize submission of known defective material, either indicated or actual, nor does it commit the Government to acceptance of defective material.

4.2 Classificationof inspections The inspection requirements specified herein are classified as follows:

4.3 shall be

4.3 contract

(a) Quality conformance “inspection (see 4.3).

(b) Verification inspection (see 4.4).

Quality conformance inspection. The quality conformance inspection in accordance with 4.3.2 through 4.3.4.

1 Certification of quality conformance. When specified in the Or order. 8 certificate of aualitv conformance shall be DreDared (see

6.2.2), for each lot offered far verification inspection.

4.3.2 Lut. A lot shall consist of assembled bearings of a particular standard par=umber assembled at the same time on the same assembly setup and processed through al1 final assembly operations as a single group. Any bearing of a lot, through its serial number, is to be sequence. Assembled bearing lot traceability traceable back to its assembly is to be maintained for 15 years.

NII.-II-17’)3II:

4.3,3 Sampling For c-y corlformancci.l!spccLiOn. Samp]ing shal1 be condtic~cdLO evaluate those charac~criscics listed in table V1 Sampling shal1 be conducted in accordance with the procedures of MIL-STD-1OS Acceptable MIL-STD-105 quality levels shall be 0.65 for major defects and 2.5 for minar defects Sampling of assembled bearings and bearing parts shall be illaccOl-dancc with inspection level II

TABLE VI Classification of defects

Category Characteristics

Najor:

lo~

Bearing component is not new and unused (see 3.4) Bearing component is not of the material specified (see 3.2) Individual besring shows evidence of corrosion (see 3.10) Individualbearing shows evidence of contamination (see 3.10) Bore diameter is not within required limit (see 3.4.7).

Outside diameter is not within required limit (see 3.4.7).

Width of individual ring is not within required limit (see 3.4.7) Radial internal clearance is not within required limit (see 3.4.7).

Preload of bearing is not within required limit (see 3.4.8)..

Duplex pair is not universal ground (see 3.4.3) Contact seal inhibits the free rotation of r.herings (see 3.4.6) Cage is not of adequate construction, interferes with rotation of bearing or impedes entrance of lubricant (see 3,4.5) Bearing lubricant is not as required (see 3.6).

Bearing is not marked as required (see 3,7) Packaging, packing, and marking are not.as required (see 5.1, 5.2, and 5.3).

116 Bearing vibration exceeds limits (see tables IV and V for vibration limits and 4.4.2 fox rejection criteria)

Minor: I

20L

20B

Hardness of each ring is not within required limit (see 3.3.1).

Hardness of each ball is not within required limit (see 3.3.2).

Dimensional stability of components is not within required limit (see 3.3.3).

Each ball scheduled for assembly is not within required limits (see 3.4.4).

Radial runout of each ring is not within required limit (see 3.4.7) Width variation of each ring is not within required limit (see 3.6.7).

Reference side runotitwith bore, inner ring, is not within the required limit (see 3.4.7).

Raceway runout with reference side, inner ring, is not within tbe required limit (see 3.4.7).

Outside cylindrical surface runout with reference side, cuter ring, is not within the required limit (see 3.4.7)

Raceway runout with reference side, outer ring, is not within the required limit (see 3.4.7)

NI1,-IJ-17931F.

4.3.4 Acceptance and rejection. Acceptance or rejection of the parts ox assembled bearing lot subjected to the sampling specified in 4.3.3 shall be in accordance with the procedures of }IIL-sTD-105. Defects shall be classified as specified in table VI

L.4 Verification inspection. Verification inspection shall be conducted at che DTNSRDC, Annapolis, Naryland, unless otherwise specified by the command at’agency concerned. Verification inspection shall be conducted on all lots of bearings offered for delivery A lot shall not be delivered until results of the verification inspection have been received. Only lots of bearings which satisfy the requirementsspecified herein and have passed the quality conformance inspection of 4.3 ‘shallbe offered for verification inspection.

4.4.1 Sampling for verification inspection. From each lot of assembled bearings the Government quality assurance representativeshall select a random sample in accordancewith table VII

TABLE VII Sample size for verification.inspection.

Lot size1 Sample sizel Acceptance number up to 13 All 1 14 to 90 13 1 91 to 150 20 2 151 to 280 32 3 281 to 500 50 5 501 to 1200 80 7 1201 to 3200 125 10 3201 to 10000 200 14

1 Duplex pairs shall be counted as one bearing.

&.4.2 Acceptance and rejection. The following criteria shall be applied to determine the acceptance and rejection of bearings submitted for verification inspection.

I

I 4.4.2.1 Individual bearings. Any individual bearing with a low, middle or high band anderon level exceeding the vibration limits specified in tabla IV for that size shall be rejec.ted. Ahy bearing which does not conform to a

I metrology requirementspecified in 3.4.7 or 3.4.8 shall be rejected. Any individual bearing exhibiting mechanical or physical damage (as defined in 3.10) shall be rejected. Duplex pairs shall be eccepted or rejected as a pair.

An individualbearing can be rejetted for more than one reason.

}lll.-1I-I7,J3IE

4.4.2.2’ Bearing lots. Ally10t of beariags shal1 be rejected when the ]rcsllltso{ the 10C sample inspection indicate citker of the following:

(a) The number of individual bearings failing the vibration limits of table IV exceeds the acceptance number listed in table VII

(b) The number of individual bearings failing the metrology require-ments of 3.4.7 or 3.4.8 exceeds the acceptance number listed in table VII.

(c) The number of individual bearings exhibiting mechanical or physical damage (as defined in 3.10) exceeds the accep-tance number listed in table VII.

(d) The combined number of individual bearings failing vibration, metrology or exhibiting damage exceeds the acceptance number in table VII.

(e) The average vibration limit of the lot sample for any part of the spectrum (low, middle, or high) exceeds the anderon limit speci-fied in table V for that size bearing.

4.4.3 Disposition of lot sample. Lot samples which have completed veri-fication inspection are handled in the following manner: Acceptable lot sample greased bearings shall be relubricated, and included in the lot for delivery. Acceptable oil lubricated.bearings shall be cleaned and relubricated, and included in the lot for delivery. Bearings that are not offered for delivery shall have the standard part number and the marking “A’’I+”obliterated.

k.4.3.l Rejected lots. h’henthe lot sample has failed the verification inspection, rejected bearings shall be repaired or replaced. If rejected bearings are repaired, they shall be included in the lot sample resubmitted for verification inspection. Once a lot sample has been rejected, the command Ot agency concerned shall have the option, in lieu of 10K sample resubmittal, to conduct 100 percent verification inspection of the lot prior to delivery.

4.4.3,2 Repaired or replacement bearings If the repaired or replacement bearings referred to in 4.4.3.1 are rejected, the number rejected shall be added to the total number of rejections for that lot sample and this cumulative total compared to the acceptance number of table VII.

4,5 Verification inspection test methods Verification inspection shall consisc of the tests specified in 4.5.1 through 4.5.2.

4 .5.1 Vibration test. Bearing vibration shall be measured on the Bearing Analysis machine (see 6.3). Test parameters shall be in accordance with 4.5.1.1 through 4.5.1.5.

4 ,5.1,1 Physical quantity measured. The physical quantity measured shall be the anderon. The anderon shall be defined as the radial vibrational velocity of the bearing outer ring in microinches per second root mean square divided by the constant 297, as measured at 1800 revolutionsper minute of the inner ring.

4.5.1.2 Frequency ranges Bearing anderon values shall be measured in three frequency ranges: Law, 50 - 300 hertz (Hz); Middle, 300 - 1800 Hz; High, 1800.- 10,000 Hz.

I Nil,-11-17’.J3lF.

I 4,5.1.6 Test load. An external thrusr load in accordance wi~h table VI1I shal1 bc applied to the hearing during the test.

TABLE VIII kads for vibration testing

Thrust load, pounds Deep groove series Angular contact series

Bore code 200 300 7~1313 7300 7400

00 20 20 01 20 20 02 20 20 03 20 30 60 60 - 04 20 35 70 70 - 05 20 45 90 90 - 06 30 55 110 110 - 07 45 65 130 140 205 08 50 75 150 175 260 09 55 85 170 245 - 10 60 100 200 280 360 11 80 115 230 330 - 12 95 135 270 390 560 13 105 :50 300 450 14 120 170 350 510 - 15 130 195 400 580 - 16 140 215 470 660 - 17 155 240 530 750 - 18 190 270 580 935 - 19 220 295 1040 - 20 250 355 21 280 3B5 775 - 22 315 455 1490 - 24 360 455 26 410 525 32 550

4.5.1.5 Test sequence. Each sample bearing shall be tested at one random location around the periphery of the stationary outer ring for each direction in which the bearing can accept operational thrust load. Therefore, types 111 and 120 require two sets of readings per bearing, whereas types 131, 133, and 134 require only one set per bearing. Grease lubricatedbearings shall be run in and the excess grease allowed to purge, Oil, in accordance with MIL-L-17331 (2190 TEP), shall be added to oil lubricated bearings and the excess allowed to purge. Anderon levels recorded shall be the highest levels observed in each range, such as low, middle, and high, after the bearing has been run at test speed and load for a period of 5 minutes.

4.5.1.6 System calibration. The mechanical and electrical frequency response of the sensing system of the Bearing Analysis machine shall be in accordance with AFBMA Standard 13.

}lll.-IF-I7,)3IE

4.5.2 Necrology test NetrolOgical measurements On bearing bores, outside diameters. widths, and radial internal clearances shall be made on all sample bear-ings rcprcscntingevery fifth lot from the same contractor The bearings ~hall not be disassembled. Additional mess.rcmcnts may be made at the option of the Government

4.6 Inspection of packagin~. Sample packages and packs, and the inspection of the preservation-packaging,packing and marking for shipment and storage shall be in accordance with the requirements of section 5 and the documents specified therein.

5. PACKAGING

(The packaging requirements specified herein apply only for direct Government acquisition.)

5.1 Preservation-packaging. Cleaning, drying, preservation, and unit packaging shall be in accordance with level A of NIL-B-197, method IA-19 only.

Polyv~nyi chloride is prohibited as a material shall be as specified in 3.6.

5.1.1 Unit marking. Individual bearings

information indicated in 3.7.with the

5.2 or C, as

5.3

6.

6.1 intended

6.2 for method IA-19 Lubricants shall be permanently marked

Packing. Packing shall be in accordancewith MIL-B-197, level A, B, specif~d (see 6.2.1).

Marking for shipment. Narking shall be in accordance with NIL-B-197.

Noms

Intended use. The ball bearings covered by this specification are for use in low vibration machinery.

Orderin,gdata.

6.2.1 Ac~uisitiOn requirements Acquisition documents should specify the following:

(a) Title, number, and date of this specification.

(b) Standard part number (see 1.2).

(c) Level of packing required (see 5.2).

N[l.-lj-li’l?lli

6.?.2 DOLO rcquil-enmtlLs. Wlte82Ullis s]]ccificat ion is tlscxiillan acquisition and data are xequircci to bc delivered, the data requiremellcs identified IN1OW shall be developed as specified by au approved Data Item Oescripcion (DD Form 1664) and delivered in accordancewith the approved Contract Data Requirements List (CDRL), incorporated into the contract, When the provisions of DoD FAR Supplement, Part 27, Sub-Part 27.410-6 (DD Form 1423) are invoked and the DD Focm 1423 is not used, the data specified below shall be delivered by the contractor in accordance with the contract or purchase order requirements. Deliverable data required by this specificationare cited in the following paragraph.

Paragraph no, Data requirement title Applicable DID no. -

4.3.1 Certification data/report UD1-A-23264 ----

(Data item descriptions related to this specification,and identified in section 6 will be approved and listed as such in DoD 5010.12-L., ANSDL. Copies of data item descriptions required by the contractors in connectionwith speci-fic acquisition functions should be obtained from the Naval Publications Snd Forms Center or as directed by the contracting officer.)

6.2.2.1 Tbe data requirements of 6.2.2 and any task in sections 3, 4, or 5 of this specification required to be performed to meet a data requirementmay be waived by the contracting/acquisitionactivity upon certificationby the offeror that identical data were submitted by the offeror and accepted by the Government under e previous contract for identical item acquired to this speci-fication. This does not apply co specific data which may be required for each contract regardless of whether an identic81 item has been supplied previously (for example, test reports)

6.3 Bearing Analysis machine. The Bearing Analysis machine is a Navy designed and constructed test device, utilizing the commercially available Anderometer Amplimeter (manufacturedby Bendix Automation and Measurement Division of Dayton, Ohio) and a mechanical drive/loadingsystem mounted on a 2,000 pound seismic mass The test bearing is mounted on a true-running spindle with flexiblebearing seat and held in position by a thrust load transmitted through a cylindrical load ring. Bearing vibration is determined on the 3-band vibration analyzer of the Anderometer Amplimeter.

6.4 Definitions. The following definitions are provided to establish the intended meaning of terms used in this specification.

6.4.1 Functional surfaces Functional surfaces are all ball and raceway surfaces (see 3.4.5 and 3.10).

6.4.2 Contact seal Contsct seal is a bearing seal that actually contacts one bearing ring with a predetermined pressure (see 3.4.6)

6.6.3 Ncgarivc s~ickout duplex pair. ,\lcgativestickout dup [es pair i.sa duplex bearing having no internal loading which is independent of external radial or axial load, or botb, carried by the bearing. A duplex pair has negative stickout when single bearing ring widths are modified during manu-facture by relieving selected faces by a certain stickout (negative stickout) creating a non-preloaded (that is, free-running)condition uhen the pair is mounted (see 3.4.8)

6.4.4 Preloaded duplex pair. Preloaded duplex pair is a duplex bearing having internal loading which is independent of any external radial or axiaI load, or both, carried by the bearing. A duplex pair is preloaded when single bearing ring widths are modified during manufacture by relieving selected faCQS by a certain stickout (positive scickouc) creating an internal preload when the pair is mounted (see 3.4.8)

6.4.5 Nonfunctional surfaces fionfunctionalsurfaces are all bearing surfaces not listed 8s functional surfaces (see 3. 10)

6.5 Surplus bearings Surplus bearings may be offered for acquisition, provided that:

(a) The bearings are submitted for verification inspection as specified herein.

(b) The contractor will furnish the Government representative the Government contract number under which che bearings were fabricated.

6.6 Subject term (key word) listing.

Bearings, ball annular Besring rings Chromium - alloy, steel, ball bearings Vibration, ball bearings

6.7 Changes from previous issue. Asterisks are not used in this revision to identify changes with respect to the previous issue due to the extensiveness of the changes.

Custodians:

Army - AV Navy - SH Air Force - 99

Review activities:

Air Force - 84

DLA - IS

User activity:

Army - AT

Preparing activity:

Navy - SH (Project 3110-0729)

29/30

MIL-B-17931E

APPENDIX

QUIET BALL BEARING APPLICATION REQUIREMENTS

10. sCOPE

10.1 *. This appendix provides application requirements for ball bearings acquired to MIL-B-17931. This appendix forms a mandatory part of MIL-B-17931 for equipment designed, or redesigned for new application, after 1 January 1987. The requirements of this appendix are not mandatory, but may be used, for the refurbishment or upgrading of, or manufacture of exact replacement for, equipment designed before 1987.

10.2 This appendix established acceptable standard application practices for the use of quiet ball bearings. It also serves to control the seleccion of quiet ball bearings for use in new or redesigned equipment.

20. APPLICABLE DOCUN3?.NTS

20.L Government documents.

20.1.1 Standards. The following standarda form a part of this specification to the extent specified herein. Unless otherwise specified, the issues of these documents shall be those listed in the issue of the Department of Defense Index of Specification and Standards (DoDISS) and supplement thereto, cited in the solicitation.

STANDARDS

MILITARY

MS19068 - Nuts, Plain, Round, Retaining, Ball and Roller Bearing, Regular Series.

MS19070 - Washers, Key Retaining, Ball and Roller Bearing, Regular

Series.

(Copies of standards and other Government documents required by contractor in connection with specific acquisition functions should be obtained from the contracting activity or aa directed by the contracting activity.)

20.2 Other publications. The following document forms a part of this specification to the extent specified herein. Unleaa otherwise apecified, the issue of the document which la DoD adopted shall be that listed in the fasue of the DoDISS specified in the aolicitatiom. Unless otherwise specified, the issue of document not listed in the DoDISS shall be the issue of the non-government document which la cukrent on the date of the solicitation.

ANTI-FRICTION BEARING MANUFACTURERS ASSOCIATION (AFBMA)

Standard 9 - Loading Rating and Fatigue Life for

Ball Bearings.

(Applicationfor copies ehould be addreased to the Anti-Friction Bearing f4anufactureaAssociation, 1101 Connecticut Avenue, N.W., Suite 700, Washington, OC 20036).

NII,-11-17931K

API’};N1)IS

30. APPLICATION REQUIREMENTS

30.1 Fatigue life. Bearing fatigue life shall be calculated illaccordance with AFBMA Standard 9. Bearing life adjustment factors shall not be used in the calculation, unless specifically permitted by the equipment specification,

30.2 Lubrication. Bearings shall be lubricatedwith grease in accor-dance with DOD-G-245O8 unless otherwise approved by the cognizant design review activity. Grease-lubricatedbearings shall be selected to have an ndm less than 350,000 (where n is speed of rotating bearing ring in revolutionsper minute and dm is mean diameter of bearing in millimeters, that is, dm = bore diameter + outside diameter). If an ndm greater than 350,000 is unavoid-able, or oil lubricationhas a demonstrable advantage in a given application, lubricatingoil in accordance with MIL-L-17331 (Nilitary Symbol 2190 TEP) shall be used.

30.3 Temperature. Quiet ball bearings shall operate at the lowest temperaturepossible. Temperature limitations of cage and closure materials establish the maximum permissible temperature at 230”F for those parts (intermittentexcursions to 300”F are acceptable). However, for normal steady-stateoperation, the bearing outer ring temperature (as measured on the outside diameter) shall not exceed 1!14°F(90”C)

30.4 Lecknuts. A mounted bearing shall be secured against a shaft shoulder by a locknur./lockwasher combination or by a self-locking locknut Applications in which bearings are not secured against shoulders by locknuts shall be approved by the design review and approval activity. Conventional locknuts and lockweshersshall be in accordance with MS19068 and NS19070.

The appropriateMS19068 and MS19070 size number is the same as the bearing’s bore code. Figure 1 shows the bearing mounting using a standard locknut and lockwasher. The key on the inner circumference of the lockwasher is fitted into a keyway (slot) machined into the shaft and one of the tongs on the outer circumferenceof the lockwasher is bent into one of the slots of the locknut.

30.4.1 Self-locking locknuts (see figure 2) sometimes referred to as prevailing torque retaining nuts, are essentialIy the same aa NS 19068 locknuts;

however, they are equipped with a compression collar made of nylon, which has a temperature range of 300”F. The CO1lar eliminates the need for a Iockwasher.

Prevailing torque retaining nuts are designed to permit convenient assembly and disassemblywith expectation to stay in place. The resilient collar follows the metal threads in engagement in the assembly. This develops compression of the collar with the metal threads of the shaft eliminating space between the threads of the shaft and CO1lar. This compression develops tension between the mating parts providing better locking action and more protection against loosening, especially from vibration.

30.5 Locknut torques Regardless of the type of locknut used, locknut torques are standardized. Acceptable locknut torques for dry thread engagement are shown in table IX. Bearing locknuts shall be tightened using a torque wrench and a two-point-locknut wrench (see figure 3) or other suitable torque wrench adapter. Locknuts shall not be hammered or beat upon.

TABLE IX. Locknut torques

Bore code oft

Locknut torque (foot-pounds)

10-20 10-20 10-20 10-20 12-35 23-50 32-60 39-70 50-80 64-90 67-100 82-125 99-150 131-175 152-200 173-250 197-275 222-325 248-375 277-425 3k5-475 380-550 380-550 380-550 380-550 380-550

MIL-Ll-17931~

30.6 Bearing fit-up. The size and physical condition of the shaft seat ou k,hicha quiet bearing is momted and the housing in which a quiet bearing is mounted must be controlled. Achieving the correct magnitude of fit is the most important factor in the proper mounting of noise-quiet bearings Tables X and XI present the required bearing inner zing bore to shaft seat fits al]dbearing outer ring outside diameter to housing bore fits, respectively, for quiat bearing use. Variations from the requirements of tables X and XI may be expropriate fOr certain special design applications and shall be submitted (with detailed technical justification) for approval of the cognizant design “ review activity and the NAVSEA Bearing and Seal Technology Branch. Such special applications include:

(a) Designs involving heavy radial loading of the bearing (as in some horizontal shaft machinery) may require a heavier interferencefit of the bearing on the shaft. A heavier interference fit would, in turn, normally require a bearing with a larger radial internal clearance (such as standard part numbers N17931-G083 and N17931-G087).

(b) Designs with the bearing outer ring rotating and the inner ring stationary require a clearance fit at the bearing inner ring and an interference fit at the bearing outer ring.

I

I

Bearing bore code

M[L-B-17931E

APPENDIX

TABLE X. Bearing-to-shaft fits (inner ring rotatin~.

Bearing I Shaft bore diameter seat diameter

(inch Max

0.3937

0.4724

0.5906

0.6693

0.7874

0.9843

1.1811

1.3780

1.5746

1.7717

1.9685

2.1654