SAE ARP 5555-2016 Recommendations for Installation of Seals in Standard Glands.pdf

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2、U 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 2016 SAE International All rights reserved. No part of this publication may be reproduced, stored in a ret

3、rieval 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 (outside USA) Fax: 724-776-0790 Email: Cust

4、omerServicesae.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/ARP5555 AEROSPACE RECOMMENDED PRACTICE ARP5555 Issued 2016-02 Recommendations for Installation of Seals in Standard Glands RAT

5、IONALE There is a need to provide information regarding hardware design considerations and installation procedures for O-rings and other elastomeric seals in hydraulic components that use standard glands. This document meets this need. FOREWORD This SAE Aerospace Recommended Practice (ARP) provides

6、recommendations for the installation of seals and seal assemblies of the type that was previously included in MIL-G-5514 (Inactive for New Design) in a SAE document to be used in conjunction with AS4716, AS4832, AS4088, AS4052, AS5857, and AS6235. TABLE OF CONTENTS 1. SCOPE 3 2. REFERENCES 3 2.1 App

7、licable Documents 3 2.1.1 SAE Publications . 3 2.1.2 ISO Publications 4 2.1.3 ASME Publications 4 2.1.4 NAS Publications 4 2.1.5 U.S. Government Publications 5 2.2 Definitions . 5 3. GENERAL DESIGN REQUIREMENTS FOR HYDRAULIC UNITS . 5 3.1 Pressure 5 3.2 Temperature 7 3.3 Design Precautions to Preven

8、t Damage to Seals during Installation . 7 3.4 Operation over Unrestrained Areas 8 3.5 Dynamic Seal Travel . 9 3.6 Standard Gland Dimensions . 9 3.7 Non-Standard Gland Dimensions . 9 3.8 Qualification of Non-Standard Glands 9 4. STANDARD O-RING AND D-RING SEALS . 9 4.1 Use of O-Rings 9 4.2 Use of D-R

9、ing Seals 10 4.3 Surface Finishes of Glands . 10 4.4 O-Ring Groove Shape. 10 4.5 Redundant Seals . 10 4.6 Breathing . 10 SAE INTERNATIONAL ARP5555 Page 2 of 17 5. NON-STANDARD HYDRAULIC SEALS . 11 5.1 Use of Non-Standard Hydraulic Seals 11 5.2 Design Considerations for Non-Standard Hydraulic Seals .

10、 11 6. ANTI-EXTRUSION DEVICES . 11 6.1 Application of Anti-Extrusion Devices (Backup Rings) . 11 6.2 Installation of Anti-Extrusion Devices 11 6.2.1 Continuous Uncut PTFE Backup Rings 11 6.2.2 Single-Turn Scarf Cut PTFE Backup Rings 12 6.2.3 Spiral PTFE Backup Rings . 12 7. STATIC SEALS . 12 7.1 O-R

11、ing Static Radial Piston and Rod Seals 12 7.2 Straight Thread Tube Fitting Boss Seals 12 7.2.1 Use of Straight Thread Tube Fitting Boss Seals . 12 7.3 Static Face Seals 13 7.3.1 Static Face Seals at temperatures from -65 to +160 F (-54 to +71 C). 13 7.3.2 Design Details for Static Face Seal Installa

12、tions 13 7.3.3 Static Face Seals at temperatures from -65 to +275 F (-54 to +135 C). 13 7.3.4 Static Face Seals at temperatures exceeding +275 F (+135 C) 13 8. DYNAMIC SEALS . 13 9. DESIGN DATA ON THE USE OF DYNAMIC AND STATIC SEALS 13 9.1 Design Data 13 9.2 O-Ring Squeeze 15 9.2.1 Change of Squeeze

13、 Considerations . 15 9.3 Diametrical Clearance . 16 9.4 General Limitations of O-rings 16 9.4.1 Friction. 16 9.4.2 Oscillation 16 9.4.3 Rotary seals 16 9.4.4 Precaution . 16 10. NOTES 17 10.1 Revision Indicator 17 FIGURE 1 RELATIVE POSITIONS OF O-RING IN GROOVES AT INCREASING PRESSURE FOR A TYPICAL

14、80 SHORE A ELASTOMER 6 FIGURE 2 TYPICAL O-RING ASSEMBLY . 7 FIGURE 3 METHOD TO AVOID SHARP INSTALLATION CORNERS . 8 FIGURE 4 TYPICAL INSTALLATION OF STATIC SEALS 14 TABLE 1 D-RING GLAND DIMENSIONS 10 SAE INTERNATIONAL ARP5555 Page 3 of 17 1. SCOPE This SAE Aerospace Recommended Practice (ARP) contai

15、ns guidance regarding hardware design and installation procedures for seals in hydraulic components that utilize standard seal glands in accordance with AS4716, AS4832, AS4088, AS4052, AS5857, and AS6235. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document

16、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. In the event of conflict between the text of this document and references cited herein, the text of this docume

17、nt 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 International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +

18、1 724-776-4970 (outside USA), www.sae.org. AS568 Aerospace Size Standard for O-rings AS1300 Port - Ring Locked Fluid Connection Type, Standard Dimensions for AS1986 Fitting Assembly, Adapter, Ring Locked Port Connection to Beam Seal, 4000 psi and 5000 psi AS4052 Gland Design: Scraper, Landing Gear,

19、Installation AS4088 Aerospace Rod Scraper Gland Design Standard AS4099 Adapter, Assembly - Port Connection Ring Locked to Flareless Tube End AS4395 Fitting End, Flared, Tube Connection, Design Standard AS4396 Fitting End, Bulkhead, Flared, Tube Connection, Design Standard AS4716 Gland Design, O-ring

20、 and Other Elastomeric Seals ARP4752 Aerospace - Design and Installation of Commercial Transport Aircraft Hydraulic Systems AS4832 Gland Design: Nominal 3/8 in Cross Section for Custom Compression Type Seals ARP4925 Aerospace Design and Installation of Commercial Transport Helicopter Hydraulic Syste

21、ms AS5202 Port or Fitting End, Internal Straight Thread, Design Standard AS5440 Hydraulic Systems, Military Aircraft, Design and Installation, Requirements For AS5781 Retainers (Backup Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Single Turn, Scarf-Cut, For Use in AS4716 Glands AS

22、5782 Retainers (Backup Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Solid, Un-Cut, For Use in AS4716 Glands AS5857 Gland Design, O-ring and Other Elastomeric Seals, Static Applications SAE INTERNATIONAL ARP5555 Page 4 of 17 AS5860 Retainers, (Back-Up Rings), Hydraulic and Pneumati

23、c, Polytetrafluoroethylene Resin, Single Turn, Static Gland AS5861 Retainers, (Back-Up Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Solid, Static Gland AS6235 Face Seal Gland Design, Static, O-ring and Other Seals for Aerospace Hydraulic and Pneumatic Applications AS8791 Hydraulic

24、 and Pneumatic Retainers (Back-Up Rings), Polytetrafluoroethylene (PTFE) Resin AS28772 5LQJ6HDOIRU6KRFN6WUXWV0ROGHGIURP$06 -P-25732 Material AS28775 Packing, Preformed - MS28775 O-ring AS28778 Packing, Preformed, Straight Thread Tube Fitting Boss AS33514 Fitting End, Standard Dimensions for Flareles

25、s Tube Connection and Gasket Seal AS33515 Fitting End, Standard Dimensions for Bulkhead Flareless Tube Connections AS83461/1 M83461 O-ring Molded from AMS-P-83461 Rubber AS83461/2 O-ring M83461 Straight Thread Tube Fitting Boss AMS-P-5510 Packing, Preformed, Straight Thread Tube Fitting Boss, Type I

26、 Hydraulic (-65 to 160F) 2.1.2 ISO Publications Available from International Organization for Standardization, ISO Central Secretariat, 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, Tel: +41 22 749 01 11, www.iso.org. Also available at http:/webstore.ansi.org/. ISO 4287-1 Geometri

27、cal Product Specifications (GPS) - Surface Texture: Profile Method - Terms, Definitions and Surface Texture Parameters 2.1.3 ASME Publications Available 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

28、 North America), www.asme.org. ASME B46.1 Surface Texture (Surface roughness, waviness Packing, Hydraulic, General Requirements For (Inactive for New Design) 2.2 Definitions 2.2.1 ANTI-EXTRUSION DEVICE OR BACKUP RING A ring or similar device assembled with a seal to prevent the seal extruding into t

29、he clearance gap. Backup Ring is an alternative description for Anti-Extrusion Device. 2.2.2 GLAND A housing or cavity defined by the boundaries of the metallic hardware for accommodating a compression packing or sealing ring or seal assembly. 2.2.3 PACKING A compression type static or dynamic seal

30、housed in a gland. Also applicable to the materials used in this type of seal. 2.2.4 SEAL A device that joins two systems or elements in such a way as to prevent leakage. 3. GENERAL DESIGN REQUIREMENTS FOR HYDRAULIC UNITS This section is intended to provide the reader with some background informatio

31、n regarding the design considerations applied to seal installations and seal assemblies resulting from the overall system requirements. 3.1 Pressure The normal working pressure used in many aircraft and helicopter hydraulic systems is 3000 psi (20680 kPa). At this system pressure seal installations

32、utilizing standard gland dimensions will require protection of the sealing element with an anti-extrusion device from premature wear and extrusion. A schematic of the behavior of a standard O-ring assembly (with and without backup rings) under varying pressure loads is shown in Figure 1. For system

33、pressures between 1500 psi (10340 kPa) and 3000 psi (20680 kPa) it is also recommended to use anti-extrusion devices unless the extrusion gaps are reduced to less than recommended in the applicable gland standard. The latter approach should be validated and qualified by similarity, analysis and test

34、 as applicable. Lower system pressures, 1500 psi (10340 kPa) and below, will generally not require anti-extrusion devices with standard gland extrusion gaps. Where higher working pressures are specified careful consideration should be given to the seal installation requirements. Systems up to 5000 p

35、si (34470 kPa), may require smaller extrusion gaps and/or tougher anti-extrusion device materials to be used. Some of the applicable backup ring standards provide material choices for high pressure systems. In these instances it is recommended to validate and qualify the component installation by si

36、milarity, analysis and test as applicable. SAE INTERNATIONAL ARP5555 Page 6 of 17 Military and commercial aircraft systems may have different operating pressure requirements and reference should be made to the either AS5440 or ARP4752 or ARP4925 for guidance on specific types of aircraft hydraulic s

37、ystem pressures. Figure 1 - Relative positions of O-ring in grooves at increasing pressure for a typical 80 shore A elastomer SAE INTERNATIONAL ARP5555 Page 7 of 17 3.2 Temperature The hydraulic system temperatures that the seal installation will be exposed to are in the range of -65 to +275 F (-54

38、to +135 C). Military and Commercial aircraft systems will have different temperature requirements and reference should be made to the either AS5440 or ARP4752 or ARP4925 for guidance on specific types of aircraft hydraulic system temperatures. 3.3 Design Precautions to Prevent Damage to Seals during

39、 Installation Hardware and components should be designed so that no damage to the seals occurs upon installation by passing the seals over threads, sharp corners or edges. Diameters or threads over which, or through which, seals confined in glands should be inserted, should be of a size that will en

40、sure a clearance between the seals and the thread or diameter at the least favorable extremes of tolerance. Chamfered edge annular undercuts should be used at all cross-holes. In addition chamfers should be used at the ends of bores with sloped areas clear of intersecting holes. This is required bec

41、ause where a seal under squeeze crosses even a round edge cross-hole it may be partially severed as a result of localized protrusion. The surface finish of chamfers in these situations should be consistent with the adjacent sealing bore surface finish and blended smoothly into the sealing bore. Typi

42、cal methods of undercutting and chamfering, as well as illustration of pinched seals, which are to be avoided, are shown in Figures 2 and 3. Figure 2 - Typical O-ring assembly SAE INTERNATIONAL ARP5555 Page 8 of 17 Figure 3 - Method to avoid sharp installation corners 3.4 Operation over Unrestrained

43、 Areas Designs which require the seal to pass over holes, ports, step diameters which would leave the internal diameter, external diameter, or sides of the seal unrestrained during its normal operation, should be avoided. If, however, it is necessary to deviate from the above, tests should be carrie

44、d out to substantiate the design and performance. SAE INTERNATIONAL ARP5555 Page 9 of 17 3.5 Dynamic Seal Travel A reciprocating seal gland should be located in a component in such a way that the leading edge of the groove or gland, at its position of extreme travel or adjustment, including adverse

45、tolerances, will remain sufficiently distant from the nearest edge of any chamfer, undercut, or other departure from the bore, or equivalent diameter. This is necessary so that there can be no extrusion, cutting, or other damage to the seal throughout the operating pressure and temperature ranges. I

46、n general, the same practice also applies to static seals. 3.6 Standard Gland Dimensions Glands should be made to the recommended requirements indicated in the applicable gland standard. Dimensions, tolerances, allowable eccentricities for piston rods, cylinder bores, and associated gland groove dia

47、meters should be carefully selected and closely controlled In addition the length, shape and allowable diametrical clearances for nominal seal installations should also be specified and controlled. This is necessary in order to provide the required service life, prevention of extrusion, minimum leak

48、age and freedom from binding throughout the required range of operating temperatures and pressures. 3.7 Non-Standard Gland Dimensions Glands of sizes other than standard will be referred to as non-standard herein. The use of non-standard gland cylinder bores, piston rods, etc., should be held to a minimum consistent with the design performance and weight considerat