Aerospace — Linear hydraulic utility actuator — General specifications

This document establishes the general requirements for a linear hydraulic utility actuator, herein referred to as a "utility actuator", for use in flight vehicle hydraulic systems at pressures up to 35 000 kPa (5 000 psi). These requirements include: — design requirements; — test requirements. This document is intended to be used in conjunction with the detail specification that is particular to each application. NOTE Although Brake pistons and Landing Gear Bogie (Truck) Pitch Trimmers are utility actuators, they are outside the scope of this document. This is because these devices are considered to be specialist actuator devices due to their specific duty cycles requiring a separate set of tailored requirements.

Série aérospatiale — Actionneur hydraulique linéaire à usage général — Spécifications générales

General Information

Status
Published
Publication Date
26-Sep-2019
Current Stage
6060 - International Standard published
Start Date
27-Sep-2019
Completion Date
27-Sep-2019
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ISO 18387:2019 - Aerospace -- Linear hydraulic utility actuator -- General specifications
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INTERNATIONAL ISO
STANDARD 18387
First edition
2019-09
Aerospace — Linear hydraulic utility
actuator — General specifications
Série aérospatiale — Actionneur hydraulique linéaire à usage général
— Spécifications générales
Reference number
ISO 18387:2019(E)
ISO 2019
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ISO 18387:2019(E)
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ii © ISO 2019 – All rights reserved
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ISO 18387:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................vi

Introduction ..............................................................................................................................................................................................................................vii

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 General requirements ..................................................................................................................................................................................... 7

4.1 Order of precedence ........................................................................................................................................................................... 7

4.2 Hydraulic system characteristics ............................................................................................................................................ 7

4.3 Qualification .............................................................................................................................................................................................. 7

4.4 Airworthiness requirements....................................................................................................................................................... 7

5 Functional requirements ............................................................................................................................................................................. 7

5.1 General ........................................................................................................................................................................................................... 7

5.2 Actuator type ............................................................................................................................................................................................ 7

5.3 Features incorporated within the utility actuator .................................................................................................... 8

5.4 Hydraulic fluid ......................................................................................................................................................................................... 8

5.5 Performance .............................................................................................................................................................................................. 8

5.5.1 General...................................................................................................................................................................................... 8

5.5.2 Performance cases ...................................................................... .................................................................................... 8

5.5.3 Leakage .................................................................................................................................................................................... 9

5.5.4 Seal and scraper friction ........................................................................................................................................10

5.5.5 End of travel snubbing .............................................................................................................................................10

5.5.6 Utility actuator locking means ..........................................................................................................................10

5.6 Endurance ................................................................................................................................................................................................12

5.6.1 General...................................................................................................................................................................................12

5.6.2 Duty cycle ............................................................................................................................................................................12

5.6.3 Endurance test ................................................................................................................................................................12

5.7 Fluid and ambient temperature ............................................................................................................................................12

5.8 Fluid cleanliness .................................................................................................................................................................................13

5.8.1 Operation .............................................................................................................................................................................13

5.8.2 Malfunction ...................................................................... ..................................................................................................13

5.8.3 Equipment delivery ....................................................................................................................................................13

5.9 Environmental requirements ..................................................................................................................................................13

6 Detail design requirements ...................................................................................................................................................................14

6.1 General ........................................................................................................................................................................................................14

6.2 Prevention of incorrect assembly ........................................................................................................................................14

6.3 Standard parts ......................................................................................................................................................................................14

6.4 Maintainability features ...............................................................................................................................................................15

6.5 Seals and scrapers .............................................................................................................................................................................15

6.5.1 General...................................................................................................................................................................................15

6.5.2 Gland surface finishes...............................................................................................................................................15

6.5.3 Static seals ..........................................................................................................................................................................15

6.5.4 Dynamic seals ..................................................................................................................................................................16

6.5.5 Scraper rings ....................................................................................................................................................................16

6.5.6 Back-up rings ...................................................................................................................................................................16

6.5.7 Lead in chamfers ...........................................................................................................................................................17

6.6 Fluid porting through interfacing surfaces ..................................................................................................................17

6.7 Lubrication of hydraulic elements ......................................................................................................................................17

6.8 Orifices ........................................................................................................................................................................................................17

6.9 Retainer (snap) rings ......................................................................................................................................................................17

6.10 Spring rings .............................................................................................................................................................................................18

6.11 Secondary locking .............................................................................................................................................................................18

6.12 Drainage .....................................................................................................................................................................................................18

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ISO 18387:2019(E)

6.13 Drillings ......................................................................................................................................................................................................18

6.14 Fillet radii .................................................................................................................................................................................................18

6.15 Rod ends ....................................................................................................................................................................................................18

6.16 Bearings .....................................................................................................................................................................................................19

6.16.1 General...................................................................................................................................................................................19

6.16.2 Lubrication .........................................................................................................................................................................19

6.16.3 Anti-roll feature .............................................................................................................................................................20

6.17 Threaded components ..................................................................................................................................................................20

6.18 Electro-conductive bonding ......................................................................................................................................................20

6.19 Marking ......................................................................................................................................................................................................20

6.19.1 Nameplate ...........................................................................................................................................................................20

6.19.2 Fluid identification ......................................................................................................................................................21

7 Strength requirements ................................................................................................................................................................................21

7.1 Hydraulic ...................................................................................................................................................................................................21

7.1.1 DOP definition .................................................................................................................................................................21

7.1.2 Proof pressure .................................................................................................................................................................21

7.1.3 Ultimate (burst) pressure .....................................................................................................................................21

7.1.4 Impulse fatigue ...............................................................................................................................................................21

7.1.5 Operation at full flow relief pressure ..........................................................................................................21

7.2 Loads ......... ....................................................................................................................................................................................................21

7.2.1 Buckling load ....................................................................................................................................................................21

7.2.2 Locking load (if applicable) .................................................................................................................................22

7.2.3 Limit load ............................................................................................................................................................................22

7.2.4 Limit retraction and extension .........................................................................................................................22

7.2.5 Ultimate load ....................................................................................................................................................................22

7.2.6 Bottoming loads ............................................................................................................................................................22

7.2.7 Stall load ...............................................................................................................................................................................22

7.2.8 Bench handling loads ................................................................................................................................................23

7.3 Combined hydraulic pressure and structural loading .......................................................................................23

7.3.1 General...................................................................................................................................................................................23

7.3.2 Design operating pressure and limit structural load ....................................................................23

7.3.3 Proof pressure and ultimate structural load ........................................................................................23

7.4 Mechanical fatigue ............................................................................................................................................................................23

7.5 Port strength ..........................................................................................................................................................................................23

7.6 Vibration ....................................................................................................................................................................................................24

8 Construction ...........................................................................................................................................................................................................24

8.1 Materials ....................................................................................................................................................................................................24

8.1.1 General...................................................................................................................................................................................24

8.1.2 Metals .....................................................................................................................................................................................24

8.2 Corrosion protection .......................................................................................................................................................................25

8.2.1 General...................................................................................................................................................................................25

8.2.2 Ferrous and copper alloys ....................................................................................................................................25

8.2.3 Aluminium alloys ..........................................................................................................................................................25

8.3 Forgings ......................................................................................................................................................................................................25

9 Mass ................................................................................................................................................................................................................................25

10 Installation requirements........................................................................................................................................................................25

10.1 Space envelope .....................................................................................................................................................................................25

10.2 Overtravel .................................................................................................................................................................................................26

10.3 Adjustment ..............................................................................................................................................................................................26

10.4 Dimensions ..............................................................................................................................................................................................26

10.4.1 Retracted length ............................................................................................................................................................26

10.4.2 Extended length .............................................................................................................................................................26

10.5 Interface document ..........................................................................................................................................................................26

10.6 Installation drawing ........................................................................................................................................................................27

10.7 Mounting of the actuator to structure .............................................................................................................................27

10.8 Hydraulic interfaces .........................................................................................................................................................................28

iv © ISO 2019 – All rights reserved
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ISO 18387:2019(E)

10.9 Electrical interfaces (if applicable) .....................................................................................................................................28

11 Instrumented utility actuator ..............................................................................................................................................................28

12 Maintainability requirements .............................................................................................................................................................28

12.1 General ........................................................................................................................................................................................................28

12.2 Maintenance concept ......................................................................................................................................................................28

12.3 Service life limitations and storage specifications ................................................................................................29

12.4 Reparability ............................................................................................................................................................................................29

13 Reliability requirements ...........................................................................................................................................................................29

13.1 Requirements ........................................................................................................................................................................................29

13.2 Equipment compliance .................................................................................................................................................................29

14 Quality assurance provisions ...............................................................................................................................................................29

14.1 Responsibility for inspection ...................................................................................................................................................29

14.2 First article inspection (FAI) ....................................................................................................................................................30

14.2.1 General...................................................................................................................................................................................30

14.2.2 First article samples ........................................................................................................................................... ........30

14.2.3 First article inspection report ...........................................................................................................................30

14.2.4 Rejection ..............................................................................................................................................................................30

14.3 Classification of tests ......................................................................................................................................................................30

14.4 Test stand requirements ..............................................................................................................................................................30

15 Development tests ...........................................................................................................................................................................................31

16 Acceptance tests .................................................................................................................................................................................................31

16.1 General ........................................................................................................................................................................................................31

16.2 Examination of the product ......................................................................................................................................................31

16.3 Test programme and inspection methods ....................................................................................................................32

16.3.1 General...................................................................................................................................................................................32

16.3.2 Mass .........................................................................................................................................................................................32

16.3.3 Run-in .....................................................................................................................................................................................32

16.3.4 Proof pressure .................................................................................................................................................................32

16.3.5 Leakage .................................................................................................................................................................................32

16.3.6 Performance tests ........................................................................................................................................................33

16.3.7 Electro-conductive bonding ................................................................................................................................33

16.3.8 Storage and packaging .............................................................................................................................................33

17 Qualification ...........................................................................................................................................................................................................34

17.1 Purpose .......................................................................................................................................................................................................34

17.2 Qualification procedure ................................................................................................................................................................34

17.2.1 Qualification programme plan ..........................................................................................................................34

17.2.2 Qualification test procedure ...............................................................................................................................34

17.2.3 Similarity and analysis report ...........................................................................................................................34

17.2.4 Qualification test report .........................................................................................................................................34

17.2.5 Samples and programme of qualification tests ..................................................................................34

17.2.6 Acceptance tests .........................................................................................................................................................

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