1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2014 SAE InternationalAll rights reserved. No part of this publi
3、cation may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE.TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)Tel: +1 724-776-4970 (out
4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/AS81820DAEROSPACESTANDARDAS81820 REV. DIssued 1998-03Revised 2014-07Superseding AS81820CBeari
5、ngs, Plain, Self-Aligning, Self-Lubricating,Low Speed OscillationRATIONALEThe reason for updating this document is to clarify the requirements for the subzero testing for Type A bearing qualification, mandate passivation for 440C balls after June 1, 2015, add Liquid Nitrogen testing requirements and
6、 to remove chrome plating on the ball OD.1. SCOPEThis SAE Aerospace Standard (AS) covers plain spherical bearings which are self-aligning and self-lubricating by utilizing polytetrafluoroethylene (PTFE) in a fabric composite or molded material that is bonded to the inner diameter surface of the race
7、 and when specified, to the bore diameter surface of the ball. These bearings are for use in the temperature range -65to +325 F (-54 to +163 C).2. APPLICABLE DOCUMENTSThe following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall ap
8、ply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In theevent of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable
9、laws and regulations unless a specific exemption has been obtained.2.1 SAE PublicationsAvailable from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.AS1241 Fire Resistant Phosphate Ester Hydra
10、ulic Fluid for AircraftARP5448/4 Plain Bearing Bond Integrity - Peelable Woven Fabric PTFE LinersARP5448/5 Plain Bearing No-Load Rotational Breakaway Torque MeasurementARP5448/8 Plain Spherical Bearing Radial and Axial Clearance MeasurementARP5448/9 Plain Bearing Lined Inside Diameter Plug GagingSAE
11、 INTERNATIONAL AS81820D Page 2 of 23AS8243 Anti-Icing and Deicing - Defrosting FluidsAS8942 Bearings, Plain and PTFE Lined, Self-AligningAS14101 Bearing, Plain, Self-Lubricating, Self-Aligning, Low Speed, Narrow, Grooved Race, -65 to +325 FAS14102 Bearing, Plain, Self-Lubricating, Self-Aligning, Low
12、 Speed, Wide, Chamfered Race, -65 to +325 FAS14103 Bearing, Plain, Self-Lubricating, Self-Aligning, Low Speed, Wide, Grooved Race, -65 to +325 FAS14104 Bearing, Plain, Self-Lubricating, Self-Aligning, Low Speed, Narrow, Chamfered Race, -65 to +325 FAS81820/1 Bearing, Plain, Self-Aligning, Self-Lubri
13、cating, Lined Bore, Low Speed, Narrow, Grooved Race, -65 to +325 FAS81820/2 Bearing, Plain, Self-Aligning, Self-Lubricating, Lined Bore, Low Speed, Wide, Chamfered Race, -65 to +325 FAS81820/3 Bearing, Plain, Self-Aligning, Self-Lubricating, Lined Bore, Low Speed, Wide, Grooved Race, -65 to +325 FAS
14、81820/4 Bearing, Plain, Self-Aligning, Self-Lubricating, Lined Bore, Low Speed, Narrow, Chamfered Race, -65 to +325 FAMS1424 Deicing/Anti-Icing Fluid, Aircraft, SAE Type IAMS2417 Plating, Zinc-Nickel AlloyAMS2700 Passivation of Corrosion Resistant SteelsAMS5629 Steel, Corrosion-Resistant, Bars, Wire
15、, Forgings, Rings, and Extrusions, 13Cr - 8.0Ni - 2.2Mo - 1.1Al, Vacuum Induction Plus Consumable Electrode Melted, Solution Heat Treated, Precipitation HardenableAMS-QQ-P-416 Plating, Cadmium (Electrodeposited)2.2 ASTM PublicationsAvailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C
16、700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org.ASTM F25 Standard Test Method for Sizing and Counting Airborne Particulate Contamination in Clean Rooms and Other Dust Controlled Areas Designed for Electronic and Similar ApplicationsASTM F50 Standard Practice for Continuous Siz
17、ing and Counting of Airborne Particles in Dust Controlled Areas Using Instruments Based Upon Light Scattering PrinciplesASTM C794 Standard Test Method for Adhesion-in-Peel of Elastomeric Joint SealantASTM A967 Standard Specification for Chemical Passivation Treatments for Stainless Steel PartsSAE IN
18、TERNATIONAL AS81820D Page 3 of 232.3 ASME PublicationsAvailable from ASME, P.O. Box 2900, 22 Law Drive, Fairfield, NJ 07007-2900, Tel: 800-843-2763 (U.S./Canada), 001-800-843-2763 (Mexico), 973-882-1170 (outside North America), www.asme.org.ASME B46.1 Surface Texture (Surface Roughness, Waviness, an
19、d Lay)ASME Y14.24 Types and Applications of Engineering DrawingsASME Y14.34M Associated ListsASME Y14.35M Revision of Engineering Drawings and Associated DocumentsASME Y14.100 Engineering Drawing Practices2.4 U.S. Government PublicationsAvailable from DLA Document Services, Bldg 4/D, 700 Robbins Ave
20、, Philadelphia, PA 19111, Tel: 215-697-6396, http:/quicksearch.dla.mil/ or http:/ DoD Standard Practice Military Marking for Shipment and StorageMIL-DTL-197 Packaging of Bearings, Anti-Friction, Associated Parts and Sub-AssembliesMIL-STD-2073-1 Standard Practice for Military PackagingMIL-PRF-5606 Hy
21、draulic Fluid, Petroleum Base; Aircraft, Missile and OrdnanceMIL-DTL-5624 Turbine Fuel, Aviation, Grades JP-5 and JP-5/JP-8 STMIL-PRF-7808 Lubricating Oil, Aircraft Turbine Engine, Synthetic Base, NATO Code Number O-148MIL-PRF-83282 Hydraulic Fluid, Fire Resistant, Synthetic Hydrocarbon Base, Aircra
22、ft, Metric, NATO Code Number H-5373. REQUIREMENTS3.1 QualificationBearings furnished under this standard shall be products which are authorized by the qualifying activity for listing on the applicable Qualified Products List (QPL-AS81820) at the time of award of contract (see 4.3 and 6.3). See Quali
23、fied Products Database (QPD) at http:/quicksearch.dla.mil/, or http:/ MaterialsThe ball, race and liner shall conform to the applicable AS sheet.3.2.1 PlatingWhen specified, plating of the race shall be Zinc-Nickel plating in accordance with AMS2417 Type 2 Grade A or B and the applicable drawing or
24、Cadmium plating per AMS-QQ-P-416 Type II, Class 2 and the applicable drawing.When AMS2417 is specified, only Type 2 Grade B shall be permitted on bearings manufactured after June 1, 2015.SAE INTERNATIONAL AS81820D Page 4 of 233.2.2 Passivation3.2.2.1 PH13-8 BallsPH13-8 steel balls shall be passivate
25、d in accordance with AMS2700, Method 1 (Nitric Acid) or Method 2 (Citric Acid), or ASTM A967 Citric 1, Citric 2, and Citric 3 are acceptable. A permissible method for determining passivity is the Copper Sulfate test defined in ASTM A967 or AMS2700.3.2.2.2 440C Steel BallsThe passivation of 440C stee
26、l balls is mandatory on all parts manufactured after June 1, 2015. The balls shall be passivated in accordance with AMS2700, Method 1 (Nitric Acid) or Method 2 (Citric Acid), or ASTM A967 - Citric 1, Citric 2, and Citric 3 are acceptable. The preferred method for determining passivity on 440C balls
27、is the Copper Sulfate test defined in ASTM A967 or AMS2700.3.3 DesignBearing design shall conform to the applicable AS sheet (AS81820/1, AS81820/2, AS81820/3, AS81820/4, AS14101, AS14102, AS14103, and AS14104).3.4 ConstructionThe liner shall be secured such that all relative motion will be between t
28、he liner wear surface and the ball, or in the case of lined bore bearings between the liner wear surface and the shaft. The bearing shall not have loading slots.3.4.1 Dimensions and TolerancesDimensions and tolerances shall be specified on the applicable AS sheet. Dimensions not shown shall be at th
29、e option of the manufacturer. Lined bores shall be inspected per ARP5448/9.3.4.2 Surface TextureAll specified surface textures shall be in accordance with the applicable AS sheet and ASME B46.1 (see 4.5.1).3.4.3 LubricationInitial grease or oil lubrication by the manufacturer shall not be permitted.
30、3.4.4 ConformityFor bearings with composite type liners, the conformity of the ball and race shall be measured normally. For bearings with molded liners, the conformity of the ball and race shall be measured both normally and circumferentially (see 4.6.8).3.4.4.1 Fabric LinersThe normal conformity b
31、etween the ball and race shall be checked in accordance with 4.6.8.1. For fabric composite type liners, measurements shall be taken at a minimum of five uniformly spaced positions across the bearing. Variation between measured values shall not exceed 0.003 inch. When overforming of the race is obser
32、ved per 4.6.8.1, then the measured values in the outer 10% of the race width shall not vary from the above measured maximum value by more than 0.005 inch. Underforming is not controlled.SAE INTERNATIONAL AS81820D Page 5 of 233.4.4.2 Molded LinersNormal conformity of bearings with molded liners shall
33、 be measured in accordance with 4.6.8.1. The precise shape of the cavity containing the liner material is not defined. The cavity shall not exhibit sharp angular changes in curvature across the width of the bearing. Dimension “t“ shall be measured initially at the midpoint and H/10 positions (see Fi
34、gure 3B). The allowable values at the H/10 positions for the applicable drawings referenced in 3.3 shall be 0.011 inch 0.003 inch for all sizes. The permitted variation within any one bearing shall not exceed 0.004 inch. The maximum liner thickness shall occur at the midpoint and the allowable value
35、s of “t“ at the midpoint shall be equal to, or greater than, the H/10 values butnot greater than 0.022 inch. In addition to the three initial measurements, the outer 10% of the race width shall be checked for overforming and the measured values of “t“ in these regions shall be not less than 0.008 in
36、ch.3.4.4.3 Circumferential ConformityIn molded liner bearings, the circumferential conformity shall be measured in accordance with 4.6.8.2. Variation in measured values of “G“ shall not exceed 0.003 inch (see Figure 4).3.4.5 PTFE Liner Condition3.4.5.1 Visual ExaminationThe liner shall be uniform in
37、 texture and shall contain no embedded contaminants. The liner setback shall meet the applicable drawing requirements. Any liner seam gap shall be as qualified. There shall be no separation or lifting of the liner at any of the edges. Unraveling and fraying is not permitted outside the set back area
38、. Molded liners shall completely fill the cavity between the ball and race and shall not contain embedded contaminants, cracks or bubbles.3.4.5.2 Bond Integrity and Peel StrengthWhen tested in accordance with 4.6.9.2, the liner shall adhere to the metallic substrate at least 90% of the contact area
39、and shall exhibit an average peel strength of 2.0 pounds per inch or greater. The adhesive remaining on the metal substrate shall have no void or unbonded areas which cannot be included within a circumscribing circle with a diameter equal to 25% of the race width or 0.25 inch, whichever is smaller.3
40、.4.5.2.1 Processing ControlsAll fabrication of the PTFE liner involving application or mixing of adhesive, and all liner bonding procedures involving application of adhesive, shall be conducted in a controlled area.3.4.5.2.1.1 Controlled AreaThe controlled area shall be maintained at a temperature o
41、f 75 F 10 F (18.3 to 29.4 C) with a maximum relative humidity of 75%. The enclosed atmosphere of the work area shall be well ventilated and maintained so that the particle count is 2500/cubic foot maximum for particles 5.0 microns or larger when measured per ASTM F25 or ASTM F50. The particle count
42、measurement shall be performed annually as a minimum. There shall be no eating or smoking in the controlled area and no process which produces uncontrolled spray, dust, fumes or particulate matter.3.4.5.3 Liner PeelabilityEach manufacturer shall establish during qualification testing whether the lin
43、er is peelable or non-peelable. A peelable liner is one that is capable of being stripped or sloughed off in one continuous piece without breakage of the fabric fiber. If peelable, the manufacturer shall determine the mean and standard deviation peel strength values for the liner based upon a minimu
44、m of six peel strength tests conducted in accordance with 4.6.9.2. This data shall be recorded in the qualification test report. A liner originally qualified as peelable shall remain peelable in production. A liner originally qualified as non-peelable shall remain non-peelable in production.SAE INTE
45、RNATIONAL AS81820D Page 6 of 233.5 Performance3.5.1 Radial Static Limit LoadAfter the radial load listed on the applicable AS sheet has been applied as specified in 4.6.1, the total deflection of the bearing and fixture shall be in accordance with the values shown in Table 1. In all instances the pe
46、rmanent set shall be less than 0.003 inch, and less than 0.006 inch for lined bore bearings.TABLE 1 - TOTAL ALLOWABLE DEFLECTION FOR RADIAL STATIC LIMIT LOAD-3 thru -6 Sizes -7 and -8 Sizes -9 and -10 Sizes -12 thru -16 SizesPlain SphericalBearings 0.010 inch 0.015 inch 0.017 inch 0.020 inchLined bo
47、re SphericalBearings0.020 inch 0.030 inch 0.034 inch 0.040 inch3.5.2 Axial Static Limit LoadAfter the axial load listed on the applicable AS sheet has been applied as specified in 4.6.2, the permanent set shall be less than 0.005 inch.3.5.3 Ultimate LoadNo fracture of the race or ball, or pushout of
48、 the ball shall occur when 1.5 times the radial or axial limit load is applied, as specified in 4.6.1 or 4.6.2.3.5.4 Oscillation Under Radial LoadWhen tested in accordance with 4.6.3, the bearing shall not exhibit metal-to-metal contact between the ball and race. The measurement method of 4.6.3 indi
49、cates total liner wear. The total liner wear of the bearing shall not exceed the values specified in Table 2, and the loaded rotational breakaway torque shall not exceed the value specified in Table 7. When inspected in accordance with 4.6.9.2, bond integrity shall be as specified in 3.4.5.TABLE 2 - MAXIMUM ALLOWABLE WEAR AF
