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 reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication ma
3、y 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: 724-776-4970 (outside USA)
4、Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS4052BAS4052B AEROSPACESTANDARDIssued 1994-04 Reaffirmed 2006-08 Revised 2008-11 Superseding AS40
5、52A (R) Gland Design: Scraper, Landing Gear, Installation RATIONALECompatibility issues with the traditional urethane and nitriles materials used as part of scraper assemblies designed into this specification have lead to the use of metal spring energized PTFE scrapers in landing gear. These spring
6、energized PTFE scrapers cannot be installed into the traditional AS4052 glands, resulting in the need for an alternative scraper gland design with a reduced atmospheric retention lip, allowing for a “click fit” of the scraper into the hardware 1. SCOPE This SAE Aerospace Standard (AS) covers an alte
7、rnate gland design for the installation of scraper/ wiper rings in the lower end of landing gear shock struts for the purpose of contaminant exclusion. The defined scraper gland covered by this document, as shown in Table 1, is a variant of AS4716, the accepted gland standard for MS28775, O-ring pac
8、king seals. Piston rod diameters, gland internal diameters, groove sidewall angles and the surface finish are all defined by AS4716, but the gland outer retaining wall diameter is changed. The traditional scraper design installed into the glands detailed in Table 1 typically utilize components made
9、from urethane or nitrile materials. These scraper designs, while still acceptable, must be reviewed in consideration to deicing, cleaners and disinfectant fluids applied to or in contact with the landing gear, as the materials of construction for the installed scrapersmay not be compatible to these
10、fluids. Exposure of the scraper to incompatible fluids is likely to reduce the performance of the scraper. In addition, an alternative scraper gland is also covered by this document and shown in Table 2. It is also a variant of AS4716, however this gland has a reduced atmospheric gland lip and profi
11、led lead in geometry to allow for a PTFE jacket metal spring energized scraper to be installed. The advantages of the PTFE jacket metal spring energized scraper design is that the materials of construction are chemically inert, greatly reducing the possibility of negative performance due to incompat
12、ibility with deicers, cleaners and disinfectant fluids.AS4088 is similar to the hardware design in Table 1 of this document, which was developed by SAE A-6 for flight control and general-purpose cylinders. It differs from this document primarily by the clearance between the rod (piston) and outer gl
13、and wall. 1.1 Purpose This document is intended to present a groove which will accommodate an improved scraper/wiper ring assembly design and is not intended to obsolete the MS33675 gland standard. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or net
14、working permitted without license from IHS-,-,-SAE AS4052B - 2 -1.1.1 Design Practice Historically, the most common scraper gland has been an MS33675, which accepted either a MS28776 bronze scraper or a comparable TFE scraper. It has been noted that this arrangement is deficient in two aspects: the
15、metal scraper ring is split, allowing contaminants to pass through and around it; and, being installed in a very abbreviated gland, the scraper frequently dislodges under conditions of shock strut deflection. An improved metal, plastic, or elastomeric endless scraper ring would require additional gl
16、and volume with greater retaining surfaces than specified by MS33675 and as detailed in this specification. The recommended gland geometry for AS4052 is separated into Type 1 and Type 2 as shown below.FIGURE 1 - TO ACCOMPANY TYPE 1 IN TABLE 1 Copyright SAE International Provided by IHS under license
17、 with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS4052B - 3 -TABLE 1 - TYPE 1 GLAND DIMENSIONAL INFORMATION ALL DIMENSIONS IN INCHES dPiston Rod O.D. Ref. DGlandI.D.KRetainingLip I.D. GGland +0.010 Length 0.000 GlandSize Code Dash No. +0.0000.002+0.002
18、0.000+0.0000.0103253263273283291.4981.6231.7481.8731.9981.8701.9952.1202.2452.3701.6461.7711.8962.0212.1463303313323333342.1232.2482.3732.4982.6232.4952.6202.7452.8702.9952.2712.3962.5212.6462.7713353363373383392.7482.8732.9973.1223.2473.1203.2453.3693.4943.6192.8963.0213.1453.2703.39534034134234334
19、43.3723.4973.6223.7473.8723.7443.8693.9944.1194.2443.5203.6453.7703.8954.0203453463473483493.9974.1224.2474.3724.4974.3694.4944.6194.7444.8694.1454.2704.3954.5204.6450.334Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without l
20、icense from IHS-,-,-SAE AS4052B - 4 -TABLE 1 - TYPE 1 GLAND DIMENSIONAL INFORMATION ALL DIMENSIONS IN INCHES (CONTINUED)dPistonRodO.D. Ref. DGlandI.D.KRetainingLip I.D. GGland +0.010 Length 0.000 GlandSize Code Dash No. +0.0000.003+0.0030.000+0.0000.0104254264274284294.497 4.622 4.747 4.872 4.997 4.
21、974 5.099 5.224 5.349 5.474 4.686 4.811 4.936 5.061 5.186 4304314324334345.122 5.247 5.372 5.497 5.622 5.599 5.724 5.849 5.974 6.099 5.311 5.436 5.561 5.686 5.811 4354364374384395.747 5.872 5.997 6.247 6.497 6.224 6.349 6.474 6.724 6.974 5.936 6.061 6.186 6.436 6.686 4404414424434446.747 6.997 7.247
22、 7.497 7.747 7.224 7.474 7.724 7.974 8.224 6.936 7.186 7.436 7.686 7.936 4454464474484497.997 8.497 8.997 9.497 9.997 8.474 8.974 9.474 9.974 10.4748.186 8.686 9.186 9.686 10.18645045145245345410.49710.99711.49711.99712.49710.97411.47411.97412.47412.97410.68611.18611.68612.18612.68645545645745845946
23、012.99713.49713.99714.49714.99715.49713.47413.97414.47414.97415.47415.97413.18613.68614.18614.68615.18615.6860.475Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AS4052B - 5 -FIGURE 2 - TO ACCOMP
24、ANY TYPE 2 IN TABLE 2 TABLE 2 - TYPE 2 “CLICK FIT” GLAND DIMENSIONAL INFORMATION ALL DIMENSIONS IN INCHES dPiston Rod O.D. Ref. DGlandI.D.LLead In DiameterXRetainingLip.GGlandLengthR1AtmosphericCorner Radius GlandSize Code Dash No. +0.0000.002+0.0020.000Minimum +0.005 0.000+0.010-0.000Maximum3253263
25、273283291.4981.6231.7481.8731.9981.8701.9952.1202.2452.3701.8882.0132.1382.2632.3883303313323333342.1232.2482.3732.4982.6232.4952.6202.7452.8702.9952.5132.6382.7632.8883.0133353363373383392.7482.8732.9973.1223.2473.1203.2453.3693.4943.6193.1383.2633.3873.5123.6373403413423433443.3723.4973.6223.7473.
26、8723.7443.8693.9944.1194.2443.7623.8874.0124.1374.2623453463473483493.9974.1224.2474.3724.4974.3694.4944.6194.7444.8694.3874.5124.6374.7624.8870.032 0.334 0.009Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from
27、 IHS-,-,-SAE AS4052B - 6 -TABLE 2 - TYPE 2 “CLICK FIT” GLAND DIMENSIONAL INFORMATION ALL DIMENSIONS IN INCHES (CONTINUED)dPistonRodO.D. Ref. DGlandI.D.LLead In DiameterXRetainingLip.GGlandLengthR1AtmosphericCornerRadiusGlandSize Code Dash No +0.0000.003+0.0030.000 Minimum+0.0050.000+0.010-0.000Maxim
28、um4254264274284294.497 4.622 4.747 4.872 4.997 4.974 5.099 5.224 5.349 5.474 5.0175.0425.2675.3925.5174304314324334345.122 5.247 5.372 5.497 5.622 5.599 5.724 5.849 5.974 6.099 5.6425.7675.8926.0176.0424354364374384395.747 5.872 5.997 6.247 6.497 6.224 6.349 6.474 6.724 6.974 6.2676.3926.5176.7677.0
29、174404414424434446.747 6.997 7.247 7.497 7.747 7.224 7.474 7.724 7.974 8.224 7.2677.5177.7678.0178.2674454464474484497.997 8.497 8.997 9.497 9.997 8.474 8.974 9.474 9.974 10.4748.5179.0179.51710.01710.51745045145245345410.49710.99711.49711.99712.49710.97411.47411.97412.47412.97411.01711.51712.01712.
30、51713.01745545645745845946012.99713.49713.99714.49714.99715.49713.47413.97414.47414.97415.47415.97413.51714.01714.51715.01715.51716.0170.042 0.475 0.012Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,
31、-SAE AS4052B - 7 -2. REFERENCES 2.1 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 of the purchase order
32、. 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. 2.1.1 SAE Publications Available from SAE
33、 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.AS568 Aerospace Size Standard for O-rings AS4716 Gland Design, O-ring and Other Elastomeric Seals 2.1.2 U.S. Government Publications Available from
34、the Document Automation and Production Service (DAPS), Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6257, http:/assist.daps.dla.mil/quicksearch/.MIL-G-5514 Gland Design; Packings, Hydraulic, General Requirements for (This document is obsolete for new designs)MS28776 Sc
35、raper, Piston Rod (This document is obsolete for new designs) MS33675 Scraper, Installation, Packing Gland Ring (This document is obsolete for new designs) 3. REQUIREMENTS 3.1 The gland length shown in Tables 1 and 2 are AS4716 one backup O-ring groove length. This groove provides the desired roll s
36、tability with improved scraper assembly designs of plastic and elastomeric materials. A shorter gland (AS4716, zero backup length) was deleted from this document because of stability and increased ingression problems.3.2 Gland surface finishes should be 64 in Ra or better, and be free of nicks, scra
37、tches, or burrs which could damage the scraper on installation. 3.3 This AS is a design standard and not to be used as a part number. 3.4 Glands meeting the requirements of this document have been classified under FSC-1650. 4. NOTES 4.1 A change bar (l) located in the left margin is for the convenie
38、nce of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in
39、 original publications, nor in documents that contain editorial changes only. PREPARED BY SAE SUBCOMMITTEE A-5B, GEARS, STRUTS & COUPLINGS OF COMMITTEE A-5, AEROSPACE LANDING GEAR SYSTEMS Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
