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 ther
2、efrom, 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 2013 SAE International All rights reserved. No part of this
3、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 DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-49
4、70 (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/ARP719BAEROSPACE RECOMMENDED PRACTICE ARP719 REV. B Issued 1961-12 Revised 1990-
5、11 Reaffirmed 2007-11 Stabilized 2013-06Superseding ARP719A Gas Motor RATIONALE This document has been determined to contain basic and stable technology which is not dynamic in nature. STABILIZED NOTICE This document has been declared “Stabilized“ by the A-6C6 Power Sources Committee, and will no lo
6、nger be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability of technical requirements. Newer technology may exist. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted
7、without license from IHS-,-,-TABLE OF CONTENTS1. SCOPE 31.1 General 31.2 Specific 31.2.1 Life .31.2.2 Environment and Performance 32. REFERENCES 32.1 Applicable Documents .32.1.1 U.S. Government Publications .32.2 Definitions 42.2.1 Gas 42.2.2 Gas Motor 42.2.3 Exclusions 43. DESIGN AND FABRICATION .
8、43.1 Materials .43.2 Design and Construction.53.3 Static Performance .63.3.1 Stall Torque.63.3.2 Friction 63.3.3 Quiescent Leakage.73.4 System Dynamics .73.5 Environmental Conditions .73.5.1 Vehicle Environment .73.5.2 Motor Environment83.5.3 Storage Environments 9SAE ARP719B Page 1 of 11_ Copyright
9、 SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE OF CONTENTS (Continued)4. TEST REQUIREMENTS.94.1 Functional Tests94.1.1 Efficiency.94.1.2 Quiescent Flow (Positive Displacement Motors) 94.1.3 Motor Rever
10、sal (Positive Displacement Motors).94.1.4 Stall Torque.94.1.5 Slow Speed Operation 94.2 Vibration Testing.104.3 Shock Testing .104.4 Acceleration Testing .104.5 Dynamic Testing .104.6 Endurance Testing104.6.1 Low Temperature Testing .104.6.2 High Temperature Testing 115. PREPARATION FOR DELIVERY.116
11、. NOTES11SAE ARP719B Page 2 of 11_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1. SCOPE:1.1 General:It is intended that this SAE Aerospace Recommended Practice (ARP) will set down guidelines for
12、the development and test of gas motors to provide a practical and reliable hot gas rotary actuation mechanism. Specific operational and test requirements shall be specified in a detail specification.1.2 Specific:The areas to be discussed are: Requirements (performance, environment, life, and reliabi
13、lity), design and fabrication, and test considerations.1.2.1 Life: This ARP will define in a general way the life requirements of “gas motors“ for three broad categories of flight vehicles.1.2.1.1 Long-Range Air Breathing Vehicles: The motors for vehicles, which will have a long operational life in
14、proportion to their ground checkout life.1.2.1.2 Manned Reentry Vehicles: The motors for vehicles, which will have a moderately long operational life and will be significantly less than their ground checkout life.1.2.1.3 Single Use Vehicles: The motors for vehicles, which have a long ground checkout
15、 life in proportion to their operational life and that range from seconds to an hour or more.1.2.2 Environment and Performance: This ARP will be confined to discussing the environments and gas temperatures most likely to be encountered, listing some of the performance parameters without numerically
16、defining them, and to specifying tests to show compliance with the performance and reliability requirements under the expected environmental conditions. This ARP will not define a specific “gas motor.“2. REFERENCES:2.1 Applicable Documents:The following documents form part of this ARP specified here
17、in. The latest issue of SAE documents shall apply. The applicable issue of other documents shall be as specified in the procurement specification.2.1.1 U.S. Government Publications:Military SpecificationsMIL-P-8564 Pneumatic System Components, Aeronautical, General SpecificationSAE ARP719B Page 3 of
18、 11_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2.2 Definitions:The following terms used in this document are defined as follows:2.2.1 Gas: Gas for the purpose of this ARP shall be defined as th
19、e gaseous product(s) resulting from the decomposition, dissociation, or combustion of liquid or solid mono or bipropellants. Where other gases such as heated N2, H2, H20 (steam), etc., which may have similar physical and/or chemical properties as the defined “gas“, are used to effect testing economi
20、es; they may be considered as being included in this ARP.2.2.2 Gas Motor: A gas motor, for the purpose of the ARP, shall be considered to include any gas powered device including positive displacement devices, which in its energy converting stage changes gas energy to rotating mechanical power.2.2.3
21、 Exclusions: To be considered in the development of the “gas motor“ but not a part of this ARP, are such devices as the servocontrol valve, the speed reducer or output conversion device, the servoloop feedback mechanisms, and dynamic characteristics of the driven load.3. DESIGN AND FABRICATION:3.1 M
22、aterials:All materials must be carefully selected to insure against wide variations of thermal expansion between adjacent members.3.1.1 All materials under highly stressed conditions must be carefully selected so that stress-creep at temperature is held to a minimum.3.1.2 Factors to be considered fo
23、r the selection of materials at the operating temperature for a given time shall include: (a) thermal coefficient of expansion, (b) stress level at that temperature, (c) creep, (d) corrosion and heat resistance, and (e) erosion.3.1.3 Protective coatings to guard against oxidation and corrosion of th
24、e base metal must be used wherever the base metal may be subjected to levels and durations of temperatures above its upper limit of oxidation resistance.3.1.4 Solid-phase dry lubricants to reduce friction forces and increase life may be advisable where the temperature range is such that they may be
25、used.3.1.5 Organic materials for seals, diaphragms, etc., may be used, but are not recommended for long life applications, in critical areas.3.1.6 The use of material combinations whose chemical reactions to each other are accelerated by high temperature shall be avoided.SAE ARP719B Page 4 of 11_ Co
26、pyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.2 Design and Construction:Design and construction of the motor shall be such that the erosion or buildup, due to the reaction of the gases and the mate
27、rials will not result in reduced reliability or abnormal operation at the required temperature for a specified time.3.2.1 Rotating members shall be mounted in bearings of adequate size to carry the maximum loads for the design life of the unit.3.2.2 Inasmuch as no handbook data exists on bearing ope
28、rations at highly elevated temperatures, cautious judgement should be exercised at all times, even at the possible expense of added weight, to insure against seizure or galling.3.2.3 In applications where output shaft seals may be required, low-force pressure-balanced seals should be employed. If sh
29、aft seal leakage is critical, there may be some advantage in dual shaft seals. Dual seals may require venting to avoid overpressure. A checkout/inspection method for determining if either seal is faulty should be incorporated, if practical.3.2.4 All positive displacement motor clearances should be s
30、elected so that a minimum quiescent flow is attained when the unit is motionless under a static load or unloaded.3.2.5 All moving members shall be mounted in such a manner that G loadings and shock do not deteriorate performance and life, and so that they do not cause destructive vibrations in thems
31、elves or to the rest of the motor and related and/or attached equipment.3.2.6 The moment of inertia of the rotating members of the motor shall be as low as possible consistent with ruggedness, reliability, and good design practice. For any specific motor application, the minimum frequency response s
32、hould be specified.3.2.7 Due to the high weight penalty for the hot gas to be used in most cases, the motor overall gas consumption shall be as low as possible. However, gas consumption at maximum output horsepower may not, in many cases, be as critical as low gas consumption at either low output to
33、rque, low output speed, or even under quiescent conditions. In all probability, a large amount of the motor usage will be at less than 10% of peak power, with high system pressure on the motor.3.2.7.1 The choice of selection between positive displacement and nonpositive displacement motors is depend
34、ent upon a careful review of rated conditions and operational environments.3.2.7.2 Fixed displacement, partial admission motors provide a higher degree of efficiency of gas usage at the expense of greater motor weight for the same power level and perhaps greater complexity to attain reversibility.SA
35、E ARP719B Page 5 of 11_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.2.7.3 Variable displacement (load sensitive) piston motors provide high efficiency at low output power levels, and may be the
36、 most desirable from the standpoint of gas usage for control applications, but at the expense of greater complexity and weight.3.2.7.4 In all cases the volume of the pressurizing gas, not doing useful work, shall be held to a minimum. This means that stroke displacements, clearances, and volumes mus
37、t be minimized.3.2.7.5 In all types of motors the clearances between the moving members shall be held to the absolute minimum consistent with good design practices, and the dead gas volumes shall be as low as possible.3.2.8 In the event that any dynamic spring-mass systems are used in the motor, the
38、y shall be sufficiently damped to insure against adverse operation under conditions of anticipated vibration.3.2.9 The design of the motor bearings shall not require the motor to withstand any loads other than the torsional and thrust loads resulting from the motor operation. The motor shall be moun
39、ted in such a manner to the speed reducer or other use function that the misalignment load imparted to the motor output shaft is minimized.3.2.10 In many cases the motor may be designed to operate with a servovalve of specific performance characteristic. In the design of the servo, the entire servol
40、oop must be considered to the extent that the motor dynamics match the dynamics of the valve, speed reduction, driven member, and necessary feedback circuitry.3.2.11 Because of the high reliability requirements, a high degree of workmanship must be exercised in fabricating the motor. In particular,
41、care must be exercised to avoid free particles, hanging burrs, or other contaminants which may dislodge during operation and initiate a malfunction within the motor or within the system in which it will operate. In addition, great care must be taken to insure that the random failures, premature wear
42、out, and/or unnecessary loss of efficiency can be minimized. Quality control inspection of the highest caliber, most rigid integrity, and utmost thoroughness must be exercised on even the most insignificant seeming component of the motor to insure against faulty workmanship.3.3 Static Performance:Fo
43、r positive displacement units the following three tests shall apply:3.3.1 Stall Torque: The maximum allowable stall torque shall be defined in inch pounds force (newton-meters). Since the breakout friction will have a significant effect on the weight of the unit, it should be optimized based on a tr
44、ade between servotorque response, rate, and supply pressure.3.3.2 Friction: The maximum allowable breakout friction shall be defined in inch pounds force (newton-meters). Since the breakout friction will have a significant effect on servoresolution, it should be minimized as much as possible within
45、the clearance limits required for low leakage.SAE ARP719B Page 6 of 11_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.3.3 Quiescent Leakage: The maximum allowable quiescent leakage flow shall be
46、defined in pound mass (kilograms) per minute of gas. It will occur in two forms, leakage across the load ports and external leakage to the ambient atmosphere. Here again, a trade study must be made to determine the optimum condition. All leakage is detrimental from a fuel consumption standpoint, but leakage across the load ports adds damping to the servo.3.4 System Dynamics:The motor with its speed reducer, driven function, input servovalve, amplifiers, command input, and feedback network shall comprise the control servosystem. In considering the motor dynamics,
