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 there
2、from, 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 2015 SAE International All rights reserved. No part of this p
3、ublication 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: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS5781AAEROSPACESTANDARDAS5781 REV. A Issued 2007-07 Reaffirmed 2013-11 Revised 2
5、015-04 Superseding AS5781Retainers (Backup Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Single Turn, Scarf-Cut, For Use in AS4716 Glands RATIONALE This revision updates the metric conversions and includes some minor editorial changes. 1. SCOPE This SAE Aerospace Standard (AS) cove
6、rs scarf-cut polytetrafluoroethylene (PTFE) retainers (backup rings) for use in glands in accordance with AS4716. They are for use in hydraulic and pneumatic system components as anti-extrusion devices in conjunction with O-rings, packings and other elastomeric seals for static and dynamic applicati
7、ons. Because of the construction of groove dimensions, backup rings specific to rod applications are designated “R” - Rod (Female), backup rings specific to piston applications are designated “P” - Piston (Male). Piston and rod types of virgin pigmented PTFE are also identified by color code which a
8、lso distinguishes parts to this standard from those made from virgin PTFE to other standards. 1.1 Field of Application Backup rings specified herein have been designed for a temperature range of -65 to 275 F (-54 to 135 C) and a nominal operating pressure of 3000 psi (20 684 kPa) for code 09 materia
9、l (AMS3678/9). Alternate materials to AMS3678 are offered for more arduous operating conditions. This specification includes material tests but does not include hydraulic or pneumatic performance tests. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to
10、 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 of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document
11、 takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. SAE INTERNATIONAL AS5781A Page 2 of 29 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-
12、606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org.AS4716 Gland Design, O-ring and Other Elastomeric Seals AMS3678 Polytetrafluoroethylene (PTFE) Moldings and Extrusions Unfilled, Pigmented, and Filled Components AMS3678/2 Type 2 - 15% Graphite Filled Virgin Polytetrafluo
13、roethylene (PTFE) Moldings or Extrusions AMS3678/3 Type 3 - 15% Glass, 5% Molybdenum Disulfide Filled Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions AMS3678/5 Type 5 - Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions with Pigment AMS3678/6 Type 6 - 60% Bronze Filled Virgin
14、Polytetrafluoroethylene (PTFE) Moldings or Extrusions AMS3678/7 Type 7 - Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions with 25% Carbon and Graphite AMS3678/8 Type 8 - Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions with 10% Carbon Fiber AMS3678/9 Type 9 - Virgin Polytetra
15、fluoroethylene (PTFE) Moldings with Pigment for AS4716 and AS5857 Backup Rings AMS3678/10 Type 10 - Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions with 15% Carbon Fiber 2.1.2 U.S. Government Publications Copies of these documents are available online at http:/quicksearch.dla.mil.MIL-ST
16、D-2073-1 Standard Practice for Military Packaging 2.1.3 ASME Publications Available from ASME, Two Park Avenue, New York, NY 10016-5990, Tel: 800-843-2763, www.CustomerCareasme.org.ASME Y 14.5-2009 Dimensioning and Tolerancing 2.2 Related Publications The following publications are provided for info
17、rmation purposes only and are not a required part of this SAE Aerospace Technical Report. 2.2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org.AS5857 Gland D
18、esign, O-ring and Other Elastomeric Seals, Static Applications AS5860 Retainers, (Back-Up Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Single Turn, Static Gland AS5861 Retainers, (Back-Up Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Solid, Static Gland SAE INTER
19、NATIONAL AS5781A Page 3 of 29 AMS3678/1 Type 1 - Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions AMS3678/4 Type 4 - 25% Glass Filled Virgin Polytetrafluoroethylene (PTFE) Moldings or Extrusions 2.2.2 U.S. Government Publications Copies of these documents are available online at http:/qu
20、icksearch.dla.mil.MIL-G-5514 Gland Design; Packing, Hydraulic, General Requirements For (Inactive for New Design) 3. TECHNICAL REQUIREMENTS 3.1 Metric Equivalents Dimensions and properties in inch/pound/Fahrenheit units are primary; dimensions and properties in SI units are shown as the approximate
21、equivalents of the primary units and are presented only for information. 3.2 Cylinder Breathing, Material Contraction and Expansion Consideration has been made to accommodate cylinder breathing on piston applications, calculated at 0.002 inch/inch diameter/1000 psi (0.051 mm/mm diameter/6895 kPa) al
22、ong with PTFE contraction to ensure a minimum 50% lap at the scarf-cut at -65 F (-54 C). This has required an increase in the diameter on certain larger sizes and a slight overlap at ambient will, therefore, be apparent. These parts have been designed such that the overlap at 275 F (135 C) will not
23、result in axial compression of the O-rings local to the scarf-cut, even in the worst tolerance stack-up situation. When thermal cycling is experienced under even moderate pressures, some circumferential shrinking may occur leading to the scarf cut gap increasing which could result in O-ring failure.
24、 Performance testing under these conditions is recommended. 3.3 Materials and Applications 3.3.1 Primary Material Code 09, Virgin PTFE with pigment: Parts made to material code 09 of this standard shall conform to AMS3678/9, Pigmented Virgin PTFE, Molded. x Parts made to material code 09 of this sta
25、ndard for “R” (Rod) applications shall be blue per AMS3678/9. x Parts made to material code 09 of this standard for “P” (Piston) applications shall be yellow per AMS3678/9. NOTE: Green pigmented material to AMS3678/9 is for use for “R” (Rod) backup rings to AS5860 and AS5861. Brown pigmented materia
26、l to AMS3678/9 is for use for “P” (Piston) backup rings to AS5860 and AS5861. Details of material specification, material code, color, composition, application and pressures for code 09 material applicable to this document are listed in Table 1. Other data is for alternate materials or for reference
27、 only 3.3.2 Alternate Materials As indicated above, the AMS3678/9 is the primary material recommended for these backup rings because of their pigmented colors for identification. The other materials listed in Table 1, except AMS3678/1 and AMS3678/4, can also be ordered by using the part identificati
28、on numbers of this standard. NOTE When alternate materials are selected it is recommended that adequate performance for the application be verified by operational testing. SAE INTERNATIONAL AS5781A Page 4 of 29 Table 1 - Materials and applications Material MaterialCode6 Color Composition Application
29、 Max Pressure5psi kPa AMS3678/1 N/A White Virgin PTFE 1 Not to be used N/A AMS3678/2 02 Black 15% Graphite Static & Dynamic 3000 20 684 AMS3678/3 03 Gray 15% Glass, 5% M0S2Static 4000 27 579 AMS3678/4 N/A White 25% Glass 2 Not to be used N/A AMS3678/5 05 Per Supplier Virgin, Pigmented 3 Static & Dyn
30、amic 2000 13 790 AMS3678/6 06 Brown 60% Bronze 4 Static 5000 34 474 AMS3678/7 07 Black 25% Carbon/Graphite Static 5000 34 474 AMS3678/8 08 Black 10% Carbon Fiber Static & Dynamic 4000 27 579 AMS3678/9 09 See 3.1.1 Virgin, Pigmented Static & Dynamic 3000 20 684 AMS3678/10 10 Black 15% Carbon Fiber St
31、atic & Dynamic 5000 34 474 NOTES: 1. Material to AMS3678/1 Grade A and Grade B is not to be used because both have lower physical properties and, therefore, lower performance than AMS3678/9. 2. Glass fibers can be abrasive, particularly in dynamic applications and against soft surfaces such as alumi
32、num and some grades of titanium and stainless steels. 3. Usually used for manufacturers proprietary pigment colors. 4. Not usually recommended for hydraulic systems as bronze particles can clog filters. 5. Maximum pressures indicated are for guidance purposes only and for pressures above 3000 psi (2
33、0 684 kPa) testing is recommended. 6. Material Designation Codes are derived from the appropriate slash sheets of AMS3678. 3.3.3 Color Identification for Materials Other Than Code 09 Color pigmentation for material to AMS3678/5 is usually proprietary per manufacturer. There is no color pigmentation
34、applied to materials to AMS3678/1, AMS3678/2, AMS3678/3, AMS3678/4, AMS3678/6, AMS3678/7, AMS3678/8, and AMS3678/10. SAE INTERNATIONAL AS5781A Page 5 of 29 3.4 Dimensional Requirements See Tables 2A, 2B, 2C, and 2D for dimensions. Dimensions and Tolerancing per ASME Y 14.5-2009. Figure 1 - Backup ri
35、ng controlled features 3.4.1 Part Number The part number consists of the standard number, the piston (P) or rod (R) code, the material code followed by the appropriate three digit dash number taken from Tables 2A, 2B, 2C, and 2D. Example P/N: $6 3 DVK1XPEH U0DWHULDO&RGH3IRU3LVWRQ5IRU5RG6WDQGDUG1XPEH
36、UNOTES: 1. In the above example Part Number, “P” for Piston, Code 09 material, and dash 123 size are all used for example purposes only. 2. Spaces between characters in the above example Part Number are for illustration clarity only and are not used in the Part Number. SAE INTERNATIONAL AS5781A Page
37、 6 of 29 3.4.2 Conformity Requirements Parts shall conform to Figure 1 and the dimensions listed in Tables 2A, 2B, 2C, and 2D. These measurements are to be made at a stabilized temperature of 73 F 2 F (23 C 1 C). NOTES: 1. Refer to A, B, and F dimensions from AS4716 in the following note. In general
38、, dimensions are based on nominal ring “OD” equal to minimum A for piston backup rings over 1.5 inches (38.100 mm). For piston backup rings under 1.5 inches (38.1 mm), the “ID” is equal to maximum F plus 0.001 inch (0.025 mm). For rod backup rings the nominal ring “ID” is equal to maximum B. In cert
39、ain sizes some adjustments are made to these rules to obtain the desired minimum 50% lap length at the scarf cut over the full range of temperature and breathing conditions. Radial width “W” is based on a net fit in the gland at maximum material condition with all features concentric. 2. In order to
40、 minimize expense of gauges by allowing commonality of backups used for glands that follow similar design principles as AS4716 (bore sizes and rod sizes generally identical to MIL-G-5514F, e.g., AS5860) the method of measuring piston type backups above 1.500 inches (38.100 mm) ID to this specificati
41、on is by the outside diameter (see Figure 1) which differs compared to previous practices. Coincidentally, this also offers better dimensional accuracy and fit through a reduction in tolerance stack-up. 3. Because a feeler gauge is required to measure the gap “G” at the scarf-cut, difficulty would b
42、e experienced in performing this measurement on sizes below 1.500 inches (38.100 mm) diameter which are, therefore, measured by placing the part on a male mandrel and measuring the gap “G” with the inside diameter restrained (see Figure 1) per previous practices. 4. Gage sizes identical to AS5860 ar
43、e as follows: x Piston types measured on ID, -009, -111 Piston types measured on OD, -128 thru -139, -222 thru -230, -325 thru -349, -425 thru -437 Rod types measured on ID, -004 thru -028, -104 thru -139, -210 thru -230, -325 thru -349, -425 thru -437 x Dash sizes other than those listed above to A
44、S5860 and this standard do not match and require unique inspection gauges. 3.4.3 Surfaces and Edges Surfaces shall be smooth and free from irregularities. Edges shall be clean and sharp. 3.4.4 Scarf-cut The scarf cut gap shall not exceed dimension “G” listed in Table 3, when measured with a gage man
45、drel diameter 0.001 inches (0.025 mm). These measurements are to be made at a stabilized temperature of 73 F 2 F (23 C 1 C). SAE INTERNATIONAL AS5781A Page 7 of 29 Table 2A - Piston (male) applications - Backup ring dimensions in inches and degrees PartNo. I.D.0.001 T0.002 W0.001 G0.0025 ADegrees AS
46、5781P(XX)-004 0.075 0.050 0.056 0.0025 39-35 AS5781P(XX)-005 0.114 0.050 0.052 0.0025 36-32 AS5781P(XX)-006 0.128 0.050 0.052 0.0025 33-29 AS5781P(XX)-007 0.157 0.050 0.053 0.0025 27-24 AS5781P(XX)-008 0.189 0.050 0.053 0.0025 22-19 AS5781P(XX)-009 0.220 0.050 0.053 0.0025 22-19 AS5781P(XX)-010 0.25
47、0 0.050 0.054 0.0025 22-19 AS5781P(XX)-011 0.312 0.050 0.054 0.0025 22-19 AS5781P(XX)-012 0.375 0.050 0.054 0.0025 22-19 AS5781P(XX)-013 0.441 0.050 0.053 0.0025 22-19 AS5781P(XX)-014 0.504 0.050 0.053 0.0025 22-19 AS5781P(XX)-015 0.566 0.050 0.053 0.0025 22-19 AS5781P(XX)-016 0.629 0.050 0.053 0.00
48、25 22-19 AS5781P(XX)-017 0.691 0.050 0.053 0.0025 22-19 AS5781P(XX)-018 0.753 0.050 0.054 0.0025 22-19 AS5781P(XX)-019 0.815 0.050 0.054 0.0025 22-19 AS5781P(XX)-020 0.881 0.050 0.054 0.0025 22-19 AS5781P(XX)-021 0.943 0.050 0.054 0.0025 22-19 AS5781P(XX)-022 1.007 0.050 0.054 0.0025 22-19 AS5781P(X
49、X)-023 1.069 0.050 0.054 0.0025 22-19 AS5781P(XX)-024 1.133 0.050 0.054 0.0025 22-19 AS5781P(XX)-025 1.196 0.050 0.054 0.0025 22-19 AS5781P(XX)-026 1.260 0.050 0.054 0.0025 22-19 AS5781P(XX)-027 1.323 0.050 0.054 0.0025 22-19 AS5781P(XX)-028 1.386 0.050 0.054 0.0025 22-19 SAE INTERNATIONAL AS5781A Pag
