1、BSI Standards PublicationBS ISO 19973-1:2015Pneumatic fluid power Assessment of componentreliability by testingPart 1: General proceduresBS ISO 19973-1:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 19973-1:2015.It supersedes BS ISO 19973-1:2007 which is
2、withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee MCE/18, Fluid power systems and components.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions o
3、f a contract. Users are responsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 85277 0ICS 23.100.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under t
4、he authority of theStandards Policy and Strategy Committee on 31 August 2015.Amendments issued since publicationDate Text affectedBS ISO 19973-1:2015 ISO 2015Pneumatic fluid power Assessment of component reliability by testing Part 1: General proceduresTransmissions pneumatiques valuation par essais
5、 de la fiabilit des composants Partie 1: Procdures gnralesINTERNATIONAL STANDARDISO19973-1Second edition2015-08-01Reference numberISO 19973-1:2015(E)BS ISO 19973-1:2015ISO 19973-1:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved
6、. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at
7、 the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 19973-1:2015ISO 19973-1:2015(E)Foreword ivIntroduction v1 Scope . 12 Nor
8、mative references 13 Terms and definitions . 14 Symbols and units of measurement . 35 Concept of reliability 36 Strategies for conducting testing . 46.1 Assumptions 46.2 Test stand and measurement of parameters . 46.3 Test planning 47 Statistical analysis . 48 Test conditions . 49 Sample size and se
9、lection criteria 510 End of test 610.1 Minimum number of failures required 610.2 Termination time of a test unit 610.3 Termination life 610.4 Suspended test unit 610.5 Censored test 611 Evaluation of reliability characteristics from the test data . 612 Test report . 813 Identification statement (ref
10、erence to this part of ISO 19973) . 9Annex A (normative) Determination of the termination life .10Annex B (informative) Determination of threshold values for leakage rates.14Annex C (informative) Calculation procedures for censored data without suspensions .21Annex D (informative) Calculation proced
11、ures for censored data with suspensions 24Annex E (informative) Verification of minimum life at a specified reliability and one-sided confidence level 28Annex F (informative) Dealing with outliers in test data .33Annex G (informative) Examples of test results .39Bibliography .44 ISO 2015 All rights
12、reserved iiiContents PageBS ISO 19973-1:2015ISO 19973-1:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical comm
13、ittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
14、International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
15、 different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO
16、 shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this docume
17、nt is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (
18、TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 131, Fluid power systems.This second edition cancels and replaces the first edition (ISO 19973-1:2007) which has been technically revised.ISO 19973 consists of the following parts, u
19、nder the general title Pneumatic fluid power Assessment of component reliability by testing: Part 1: General procedures Part 2: Directional control valves Part 3: Cylinders with piston rod Part 4: Pressure regulators Part 5: Non-return valves, shuttle valves, dual pressure valves (AND function), one
20、-way adjustable flow control valves, quick-exhaust valvesiv ISO 2015 All rights reservedBS ISO 19973-1:2015ISO 19973-1:2015(E)IntroductionIn pneumatic fluid power systems, power is transmitted and controlled through a gas under pressure within a circuit. Pneumatic fluid power systems are composed of
21、 components and are an integral part of various types of machines and equipment. Efficient and economical production requires highly reliable machines and equipment.It is necessary that machine producers know the reliability of the components that make up their machines pneumatic fluid power system.
22、 Knowing the reliability characteristic of the component, which can be determined from laboratory testing, the producers can model the system and make decisions on service intervals, spare parts inventory and areas for future improvements.There are three primary levels in the determination of compon
23、ent reliability:a) preliminary design analysis: finite element analysis (FEA), failure mode and effect analysis (FMEA);b) laboratory testing and reliability modelling: physics of failure, reliability prediction, pre-production evaluation;c) collection of field data: maintenance reports, warranty ana
24、lysis.Each level has its application during the life of a component. A preliminary design analysis is useful to identify possible failure modes and eliminate them or reduce their effect on reliability. When prototypes are available, in-house laboratory reliability tests are run and initial reliabili
25、ty can be determined. Reliability testing is often continued into the initial production run and throughout the production lifetime as a continuing evaluation of the component. Collection of field data is possible when products are operating and data on their failures are available.Specific componen
26、t test procedures and exclusions are provided in ISO 19973-2, ISO 19973-3, ISO 19973-4 and ISO 19973-5. ISO 2015 All rights reserved vBS ISO 19973-1:2015BS ISO 19973-1:2015Pneumatic fluid power Assessment of component reliability by testing Part 1: General procedures1 ScopeThis part of ISO 19973 pro
27、vides general procedures, the calculation method for assessing the reliability of pneumatic fluid power components and the methods of reporting. These procedures are independent of the kinds of components and of their design.This part of ISO 19973 also provides general test conditions and a method f
28、or data evaluation.NOTE Because the service life of any component is subject to variations, a statistical evaluation assists the interpretation of the test results.The methods specified in this part of ISO 19973 apply to the first failure without repairs (see IEC 60300-3-5), but exclude outliers; ho
29、wever, because outliers can be highly significant, information about how to deal with them is given in Annex F.2 Normative referencesThe following referenced documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, o
30、nly the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3534-1, Statistics Vocabulary and symbols Part 1: General statistical terms and terms used in probabilityISO 5598, Fluid power systems and components Vocabulary
31、ISO 6358 (all parts), Pneumatic fluid power Determination of flow-rate characteristics of components using compressible fluidsISO 10099, Pneumatic fluid power Cylinders Final examination and acceptance criteriaISO 19973-3, Pneumatic fluid power Assessment of component reliability by testing Part 3:
32、Cylinders with pistonISO 80000-1, Quantities and units Part 1: GeneralIEC 60050-191, International Electrotechnical Vocabulary, chapter 191: Dependability and quality of serviceIEC 61649, Goodness-of-fit tests, confidence intervals and lower confidence limits for Weibull distributed data3 Terms and
33、definitionsFor the purposes of this document, the terms and definitions given in ISO 3534-1, ISO 5598 and IEC 60050-191 and the following apply.3.1catastrophic failurefailure of an item that results in its complete inability to perform all required functionsINTERNATIONAL STANDARD ISO 19973-1:2015(E)
34、 ISO 2015 All rights reserved 1BS ISO 19973-1:2015ISO 19973-1:2015(E)3.2confidence coefficientconfidence levelvalue (1 ) of the probability associated with a confidence interval or a statistical coverage intervalNote 1 to entry: See also 3.6.Note 2 to entry: See ISO 3534-1 for notes related to this
35、term and definition.3.3confidence limiteither of the limits, T1or T2, of the two-sided confidence interval, or the limit, T, of the one-sided confidence intervalNote 1 to entry: See ISO 3534-1 for notes related to this term and definition.3.4failuretermination of the ability of an item to perform a
36、required functionNote 1 to entry: In the ISO 19973 (all parts), the reaching of a threshold level for statistical calculation is also considered a statistical failure (see Annex A).SOURCE: IEC 60050-1913.5one-sided confidence intervalTinterval estimator for a parameter, , comprised of the interval f
37、rom the smallest possible value of the parameter, , up to T or the interval from T up to the largest possible value of , where the probability p(T ) or p(T ) is at least equal to (1 ), where (1 ) is a fixed number, positive and less than 1Note 1 to entry: See ISO 3534-1 for notes related to this ter
38、m and definition.3.6relevant failurefailure that should be included in interpreting test or operational results or in calculating the value of a reliability performance measureSOURCE: IEC 60050-1913.7reliabilityprobability that an item can perform a required function under given conditions for a giv
39、en time intervalSOURCE: IEC 60050-1913.8sampleone or more test units taken from a population and intended to provide information on the populationNote 1 to entry: A sample can serve as a basis for a decision on the population or on the process that produced it.3.9sample sizenumber of test units in t
40、he sampleNote 1 to entry: In a multi-stage sample, the sample size is the total number of test units at the conclusion of the final stage of sampling.2 ISO 2015 All rights reservedBS ISO 19973-1:2015ISO 19973-1:2015(E)3.10three-point moving average3PMAarithmetic average of three consecutive measured
41、 components test data3.11threshold levelvalue of a performance characteristic (for example, leakage, shifting pressure, stroke time, etc.) against which the components test data is comparedNote 1 to entry: This is an arbitrary value defined by the experts as the critical value for performance compar
42、isons, but is not necessarily indicative of a component failure.4 Symbols and units of measurement4.1 The symbols used in this part of ISO 19973 are given in Table 1.Table 1 Symbol listSymbolaDefinitionB10Expected time at which 10 % of the population is predicted to fail (10 % of the lifetime distri
43、bution)(B10)95 %B10life at the one-sided 95 % confidence level Scale parameter (characteristic life) of the Weibull distributionF(t) Probability of failure, expressed in percent Shape parameter (slope) of the Weibull distributionR(t) Reliability of a component at time t ; 1-F(t)t Life time expressed
44、 in time, cycles, or distanceaOther symbols can be used in other documents and software.4.2 Units of measurement are in accordance with ISO 80000-1.5 Concept of reliabilityFor the purposes of this part of ISO 19973, reliability is the probability that a component does not have a relevant failure for
45、 a specified interval of time, number of cycles or distance when it operates under stated conditions.A relevant failure occurs when component data, determined using the three-points moving average (3PMA), exceeds a threshold level for the first time (see 10.2), or a component experiences a catastrop
46、hic failure (burst, fatigue or functional failure, etc.).Threshold levels of the components covered by ISO 19973 (all parts) are specified in the component-specific parts of this International Standard.This probability can be determined by analysing the results of a series of tests and describing th
47、e population failure by statistical methods. There are many different statistical distributions that describe the population of failures that result from testing.It is also possible to verify the minimum life of a component by the one-sided confidence estimation at a specified reliability level. Exa
48、mples are given in Annex E. ISO 2015 All rights reserved 3BS ISO 19973-1:2015ISO 19973-1:2015(E)6 Strategies for conducting testing6.1 AssumptionsThe reliability of pneumatic components in an application depends on many environmental factors, including pressure, temperature, dew point and contaminat
49、ion level of the compressed air, externally imposed loads, duty cycle, etc. Any prediction of the reliability of an individual component, therefore, shall take all of these environmental factors into consideration.This part of ISO 19973 is based on a prescribed level of stress, test conditions and duty cycle that reflects the best judgement of its developers to represent typical industrial conditions. It also includes conditions that provide consistency in the test method. Thus, the results
