1、 AEROSPACE STANDARD (R) Bearings, Ball, Airframe, Antifriction, General Standard for 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
2、suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.
3、Copyright 2004 SAE International All rights reserved. No part of this publication 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 DOCUME
4、NT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: custsvcsae.org SAE WEB ADDRESS: http:/www.sae.org Issued 1998-04 Revised 2004-08 Superseding AS7949A AS7949 REV.B NOTICE This document includes cadmium as a plating material. The use of cadmi
5、um has been restricted and/or banned for use in many countries due to environmental and health concerns. The user should consult with local officials on applicable health and environmental regulations regarding its use. 1. SCOPE: This standard covers ball bearings in the -65 to +350 F temperature ra
6、nge as specified on the applicable drawing standards. 2. APPLICABLE DOCUMENTS: The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date
7、 of the purchase order. In the event 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 laws and regulations unless a specific exemption has been obtained. Copyright SAE Inter
8、national Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS7949 Revision B - 2 - 2.1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. AMS 2417 Plating, Zinc-Nickel Alloy AMS 3652 Poly
9、tetrafluoroethylene (PTFE) Film Non-Critical Grade AMS 3666 Polytetrafluoroethylene (PTFE) Sheet, Glass Cloth Reinforced AMS 6440 Steel, Bars, Forgings, and Tubing 1.45cr (0.98-1.10c) (SAE 52100) Premium Aircraft-Quality, Consumable Electrode Vacuum Melted AMS 6444 Steel Bars, Forgings, and Tubing,
10、1.45cr (0.98 1.10c) for Bearing Applications AMS-QQ-P-416 Plating, Cadmium (Electro deposited) AS21428 Bearing, Ball, Airframe, Anti-friction, Extra Light Duty, Precision AS21443 Bearing, Ball, Airframe, Anti-friction, Pulley Type AS27640 Bearing, Ball, Airframe, Anti-friction, Heavy Duty AS27641 Be
11、aring, Ball, Airframe, Anti-friction, Intermediate Duty AS27642 Bearing, Ball, Airframe, Extra Light Duty AS27643 Bearing, Ball, Airframe, Anti-friction, Self-aligning, Double Row, Heavy Duty AS27644 Bearing, Ball, Airframe, Anti-friction, Double Row, Heavy Duty AS27645 Bearing, Ball, Airframe, Anti
12、-friction, Self-aligning, Light and Heavy Duty AS27646 Bearing, Ball, Airframe, Anti-friction, Extra Light Duty AS27647 Bearing, Ball, Airframe, Anti-friction, Extra Wide, Double Row, Intermediate Duty AS27648 Bearing, Ball, Airframe, Anti-friction, Externally Self-aligning, Extra Light Duty AS27649
13、 Bearing, Ball, Airframe, Anti-friction, Intermediate Duty Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS7949 Revision B - 3 - 2.2 ASTM Publications: Available from ASTM, 100 Barr Harbor, Wes
14、t Conshohocken, PA 19428-2959. ASTM E 1444 Standard Practice for Magnetic Particle Inspection ASTM F 2215 Standard Specification for Balls, Bearings, Ferrous and Nonferrous for Use in Bearings, Valves, and Bearing Applications 2.3 ASME Publications: Available from ASME, 22 Law Drive, Box 2900, Fairf
15、ield, NJ 07007-2900. ASME B46.1 Surface Texture (Surface Roughness, Waviness and Lay) ANSI/ABMA STD 4 Gauging/Tolerancing Practices 2.4 ISO Publications: Available from ANSI, 25 West 43rd Street, New York, NY 10036-8002. ISO 12103-1 Arizona Road Dust 2.5 U.S. Government Publications: Available from
16、Standardization Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094. Electronic copies may be obtained from http:/assist.daps.mil/quicksearch MIL-DTL-197 Packaging of Bearings, Antifriction, Associated Parts and Subassemblies MIL-PRF-23827 Grease, Aircraft and Instrume
17、nt, Gear and Actuator Screw MIL-PRF-81322 Grease, Aircraft, General Purpose, Wide Temperature Range MIL-STD-129 Standard Practice for Military Marking MIL-STD-130 Identification Marking of U.S. Military Property MIL-STD-2073-1 DoD Standard Practice for Military Packaging Copyright SAE International
18、Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS7949 Revision B - 4 - 3. REQUIREMENTS: 3.1 Drawing Standards: The individual item requirements shall be as specified herein and in accordance with the applicable drawing sta
19、ndards (see 2.1). In the event of any conflict between the requirements of this general standard and the drawing standards, the latter shall govern. 3.2 Qualification: The bearings furnished under this standard shall be products that are authorized by the qualifying activity for listing on the appli
20、cable Qualified Products List (QPL-AS7949) before contract award (see 4.3 and 6.3). 3.2.1 Product Change: Any change in product design, including raceway geometry or dimensions, nominal rolling element dimensions, rolling element quantity, seals, materials, or plant location shall be reported to the
21、 qualifying activity and may require re-qualification of the product to an extent determined by the qualifying activity. Any other specific changes that must be brought to the qualifying activitys attention shall be identified in the qualification notification letter. 3.2.2 Product Manufacture: The
22、bearing manufacturer shall be capable of performing the preponderance of manufacturing operations in-house, but may subcontract these operations at its option. Component inspection shall be performed at the plant listed on the QPL. If manufacturing operations are performed in more than one plant, th
23、e manufacturers additional plant(s) shall be reported to the qualifying activity. The manufacturer is responsible for meeting all requirements of the specification and for the quality of the end product, whether it is manufactured totally in-house or some of the operations are performed by a subcont
24、ractor. Inherent in the responsibility for the end product is the responsibility to verify that the subcontractors processes meet specification requirements. A change in subcontractor need not be reported to the qualifying activity unless specifically identified in the qualification notification let
25、ter. NOTE: Bearings partly or completely manufactured in foreign countries shall be subject to the laws and procurement regulations pertaining to acquisition of foreign-made products. 3.3 Materials: Material used to manufacture the bearing and its components shall conform to the applicable drawing s
26、tandard. The lubricant used shall be qualified to the applicable grease specification (see 3.12). Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS7949 Revision B - 5 - 3.4 Bearing Assembly: The
27、 bearing assembly shall be as specified in the applicable drawing standard, but the details of the working parts shall be optional. Only factory-new bearings shall be furnished. 3.4.1 Out-of-Roundness: The maximum and minimum bore and outside diameter readings shall be within the out-of-roundness li
28、mits specified on the applicable drawing standard. The average bore and outer diameter measurements shall be within the tolerances specified for dimensions “B“ and “D“ of the applicable drawing standard. Bearings shall be tested in accordance with 4.5.1.1. 3.4.2 Seals: Seals shall prevent the entran
29、ce of contaminants and retain the lubricant. Seals shall be securely attached to the outer ring. All relative motion shall be between the seal and the inner ring. Removable design seals, which could lead to unintended bearing disassembly, shall not be permitted on internal self-aligned bearings. 3.4
30、.2.1 Seal Test (Grease Retention): The seals shall be capable of withstanding the test requirements as specified in 4.5.2.1 without failure. Grease conforming to MIL-PRF-81322 shall be injected into the bearing. The amount of grease shall be measured by weight and shall be at least 80% of the minimu
31、m theoretical volume within the bearing. Not less than 25% of the bearing lubricant by weight shall be retained in the bearing at the end of the test. 3.4.2.2 Dust Test: After completion of the dust test specified in 4.5.2.2, the tested bearings shall meet the following requirements: a. Radial clear
32、ance shall not increase more than 50% or 0.0002 in over the pretest value, whichever is greater. b. Starting torque shall not increase more than 100% or 2 in-oz over the pretest value, whichever is greater. 3.4.2.3 Seal Retention: For bearings of internal self-aligning design, the seal retention sha
33、ll be tested in accordance with 4.5.2.3. The seals shall meet the minimum torque to dislodge the seal as specified on the applicable drawing standard. Any seal that is damaged or dislodged prior to achieving the minimum torque value shall be considered to have failed. 3.5 Interchangeability: All par
34、ts having the same MS part number shall be functionally and dimensionally interchangeable. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS7949 Revision B - 6 - 3.6 Strength Performance: 3.6.1
35、Radial Strength: 3.6.1.1 Radial Limit Load: The bearings shall meet the radial limit loads specified on the applicable drawing standard when tested in accordance with 4.5.3.1. If the smoothness of operation of the bearings has lessened perceptibly, they shall be considered to have failed. 3.6.1.2 Ra
36、dial Static Ultimate Load: The minimum radial static ultimate strength shall be 1.5 times the radial limit load value specified on the applicable drawing standard when tested in accordance with 4.5.3.2. Bearings shall be capable of being turned by hand and shall not have broken or cracked parts afte
37、r applying 1.5 times the applicable radial limit load. After the test, all rings and balls shall pass a magnetic particle inspection per ASTM E 1444. 3.6.1.3 Radial Dynamic Load: The bearing shall have a radial dynamic load rating of not less than the value specified on the applicable drawing standa
38、rd when tested in accordance with 4.5.3.3. The bearing shall have an L50life of 10,000 cycles, except for bearings covered by AS21443 which shall have an L10of 3,500 cycles. A bearing shall be considered to have failed when there is any evidence of the following defects: (1) wear of the outer racewa
39、y greater than 0.002 in; (2) 0.002 in radial displacement during testing; (3) spalling or cracking detected by magnetic particle inspection per ASTM E 1444; or (4) fracture of any component. 3.6.2 Axial Strength: 3.6.2.1 Axial Limit Load: The bearings shall meet the axial limit loads specified on th
40、e applicable drawing standard when tested in accordance with 4.5.4.1. If the smoothness of operation of the bearings has lessened perceptibly, they shall be considered to have failed. 3.6.2.2 Axial Static Ultimate Load: The axial ultimate strength shall be 1.5 times the axial load value specified on
41、 the applicable drawing standard when tested in accordance with 4.5.4.2. Bearings shall be capable of being turned by hand and shall have no cracks or broken parts after applying 1.5 times the applicable axial load. After the test, all rings and balls shall pass a magnetic particle inspection per AS
42、TM E 1444. 3.7 Internal Clearance: Radial and axial internal clearance shall conform to the applicable drawing standard when measured in accordance with 4.5.5. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from
43、 IHS-,-,-SAE AS7949 Revision B - 7 - 3.8 Plating (Except for the AS27649 Bearings): When tested in accordance with 4.5.6, all external surfaces of the bearing excluding the inner ring bore and chamfer, seal retainers, and seals, shall be cadmium plated per AMS-QQ-P-416, Type I, Class 2 or zinc-nicke
44、l plated in accordance with AMS 2417, Type 2. The plating thickness shall be 0.0003 to 0.0006 in. The plating thickness of the bore chamfers shall be a maximum of 0.0006 in. Plating on the ball loading slot is optional. 3.9 Surface Roughness: The surface roughness shall be measured in accordance wit
45、h 4.5.7, and shall conform to the values on the applicable drawing standard. 3.10 Hardness: The rings and balls shall be tested in accordance with 4.5.8. The hardness shall be in accordance with values on the applicable drawing standard. 3.11 Radial and Lateral Eccentricity: Non-self-aligning bearin
46、gs shall be tested in accordance with 4.5.9. The eccentricity values shall be in accordance with the limits specified in the applicable drawing standard. 3.12 Lubrication: The bearings shall be packed with grease qualified to MIL-PRF-81322 for -65 to 350 F operating range or MIL-PRF-23827 for -65 to
47、 250 F operating range. The bearings shall be filled with lubricant not less than 80% by volume, and shall be cleaned before the lubricant is injected into the bearings. Bearings shall not have been lubricated more than 36 months prior to the date of delivery of the bearings under contract or order.
48、 The bore of all bearings and the outside diameter of the outer ring and the inside diameter of the self-aligning ring of the externally self-aligning bearing shall be coated with the same grease that is packed in the bearing. Inspection of lubricant shall be in accordance with 4.5.10. 3.13 Dimensio
49、nal Stability: Bearings shall exhibit dimensional stability by not changing more than 0.0001 in per inch diameter from the last reading when tested in accordance with 4.5.11. 3.14 Starting Torque: Starting torque shall be within the allowable values specified in the applicable drawing standard. The amount of torque required to begin rotation of the bearing shall be measured in accordance with 4.5.12. Copyright SAE International Provided by
