30159028 pdf BS EN 14865 1 2009 ICS 45 040; 75 100 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Railway Applications — Axlebox lubricating greases Part 1 Met[.]
BRITISH STANDARD Railway Applications — Axlebox lubricating greases Part 1: Method to test the ability to lubricate ICS 45.040; 75.100 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 14865-1:2009 +A1:2010 BS EN 14865-1:2009+A1:2010 National foreword This British Standard is the UK implementation of EN 14865-1:2009+A1:2010 It supersedes BS EN 14865-1:2009 which is withdrawn The UK participation in its preparation was entrusted to Technical Committee RAE/3/-/2, Rolling bearings and lubricants The start and finish of text introduced or altered by amendment is indicated in the text by tags Tags indicating changes to CEN text carry the number of the CEN amendment For example, text altered by CEN amendment A1 is indicated by !" A list of organizations represented on this committee can be obtained on request to its secretary "Normative" - A (mandatory) requirement defined as an "expression in the content of a document conveying criteria to be fulfilled if compliance with the document is to be claimed and from which no deviation is permitted" [CEN/CENELEC Internal Regulations, Part 3: Rules for the Structure and Drafting of European Standards (PNE-Rules)] "Informative" - Information (not mandatory) intended to assist the understanding or use of the document Informativve annexes shall not contain requirements, except as optional requirements (For example, a test method that is optional may contain requirements but there is no need to comply with these requirements to claim compliance with the document This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2009 © BSI 2010 ISBN 978 580 70713 Amendments/corrigenda issued since publication Date Comments 31 December 2010 Implementation of CEN amendment A1:2010 EUROPEAN STANDARD EN 14865-1:2009+A1 NORME EUROPÉENNE EUROPÄISCHE NORM October 2010 ICS 45.040; 75.100 Supersedes EN 14865-1:2009 English Version Railway applications - Axlebox lubricating greases - Part 1: Method to test the ability to lubricate Applications ferroviaires - Graisses lubrifiantes pour btes d'essieux - Partie 1: Méthode d'essai d'aptitude lubrifier Bahnanwendungen - Schmierfette für Radsatzlager - Teil 1: Prüfung der Schmierfähigkeit This European Standard was approved by CEN on 17 January 2009 and includes Amendment approved by CEN on 14 September 2010 CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 14865-1:2009+A1:2010: E BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Contents Page Foreword 3 Introduction 4 1 Scope 5 2 Normative references 5 3 Terms and definitions 5 4 Symbols 7 5 Testing principle 8 6 Reagents and material 8 7 7.1 7.2 7.3 Test equipment 9 Test rig FE8 9 Test bearings 9 Measuring equipment 10 8 Grease sampling 11 9 9.1 9.2 9.3 Testing procedure 11 Washing procedure 11 Assembly 11 Running the test 11 10 10.1 10.2 Evaluation 12 Recording 12 Test result 12 11 11.1 11.2 11.3 Precision 13 General background 13 Repeatability 13 Reproducibility 14 12 Test report 14 Annex A (informative) Maintenance 15 Annex B (informative) Round Robin test 16 B.1 Result 16 B.2 Symbols in the Figures B.1 and B.2 16 B.3 Test data distribution 17 Annex C (informative) Precision calculation examples 18 C.1 Repeatability example 18 C.2 Reproducibility example 18 Annex ZA (informative) !Relationship between this European Standard and the Essential Requirements of EU Directive 2008/57/EC of the European Parliament and of the Council of 17 June 2008 on the interoperability of the rail system within the Community (Recast)" " 19 Bibliography 21 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Foreword This document (EN 14865-1:2009+A1:2010) has been prepared by Technical Committee CEN/TC 256 “Railway Applications”, the secretariat of which is held by DIN This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2011, and conflicting national standards shall be withdrawn at the latest by April 2011 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights This document includes Amendment 1, approved by CEN on 2010-09-14 This document supersedes EN 14865-1:2009 The start and finish of text introduced or altered by amendment is indicated in the text by tags ! " !This document has been prepared under a mandate given to CEN/CENELEC/ETSI by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive 2008/57/EC For relationship with EU Directive 2008/57/EC, see informative Annex ZA, which is an integral part of this document." This series of standards EN 14865 "Railway applications – Axlebox lubricating greases" consists of the following parts: Part 1: Method to test the ability to lubricate; Part 2: Method to test the mechanical stability to cover vehicle speeds up to 200 km/h According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Introduction This European Standard standardizes a test method and acceptance criteria for the demand in EN 12081 for testing the ability of greases to lubricate axlebox bearings It addresses the issue of lubricating ability of lubricating greases operating under severe conditions All lubricants have three main functions: to form a lubricating film that separates rolling elements and raceways, to protect the bearing from corrosion and give good longevity For lubricating greases in axleboxes there is also the demand that the product must keep the lubricating ability, sometimes without relubrication, during very long periods of time under arduous operating and environmental conditions The testing procedure in this European Standard is severe and is used to discriminate between lubricating greases of different lubricating ability BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Scope This European Standard specifies a testing method and sets the acceptance criteria for the determining of the lubrication ability of lubricating greases intended for the lubrication of axlebox bearings The lubricating ability, primarily related to the capability of lubricating greases to protect against wear, is determined in a roller bearing lubricant test rig Wear of the rolling bearing rollers, the frictional behaviour and temperature during the test are used to discriminate between lubricating greases NOTE The testing method is referred to in EN 12081 The method described is carried out in order to test axlebox greases for ordinary-speed vehicles, with speeds up to 200 km/h, and for greases intended for high-speed vehicles, with speeds up to 300 km/h The method is a discriminating process, and those greases that pass will be subject to more extensive performance tests NOTE In EN 12082 a more extensive rig performance test is described in detail This rig performance test will check the satisfactory function of the assembly of box housing, bearing, sealing and grease during a simulated journey For purpose of quality assurance and quality control, this test method is also used for batch testing of greases intended for use in axleboxes For light rail and tramway applications other standards or documents agreed between the customer and the supplier may be applied Normative references The following referenced documents are indispensable for the application of this European Standard For dated references, only the edition cited applies For undated references, the latest edition of the document (including any amendments) applies EN ISO 3170, Petroleum liquids — Manual sampling (ISO 3170:2004) EN ISO 4259:2006, Petroleum products — Determination and application of precision data in relation to methods of test ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 5725-6:1994, Accuracy (trueness and precision) of measurement methods and results — Part 6: Use in practice of accuracy values Terms and definitions For the purposes of this European Standard, the following terms and definitions apply 3.1 lubricating grease semi-solid product consisting of a mixture of liquid lubricant thickened with soaps or other thickeners, and may also contain other ingredients, imparting special properties (additives) BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) 3.2 grease lubricating ability lubricating ability of the grease during the stressing duration of the test, see 3.3, determined as the mean rolling elements wear rate from tests with four tapered roller bearings NOTE In the FE8 test, the lubricating ability of grease is determined by wear and not by the service life of the grease 3.3 stressing duration period of time, t, during which the lubricating grease sample is stressed dynamically and thermally until the test is terminated by the first failure of the test bearings or by the end of the testing period, see 3.4 3.4 testing period time required for testing, tp, until failure occurs of one of the test bearings or 500 hours if a test run without interruption NOTE For approval, the required time for a test is always 500 hours (plus an initial operation during 24 hours at 750 r/min in the 500 r/min test) If a bearing will fail earlier, the test is failed 3.5 frictional moment torque acting as a mechanical resistance to rotation, resulting from bearing friction 3.6 frictional moment of the test bearing arrangement torque, Mr, required for driving the two test bearings, see Figure 1, obtained by measuring the force for retaining the bearing housing when the shaft is rotating 3.7 frictional moment of the test bearing arrangement at start torque, Mrs, of the test bearing arrangement immediately after starting the test 3.8 run-in period period of time, Ep, from the start of the test until the steady-state is reached NOTE During the run-in period, the grease is distributed and run-in wear occurs Due to the smoothing of the contacting areas, the ratio of the lubricant film thickness to the sum of the roughness of the contact areas increases, thereby increasing the separating effect of the lubricant film Depending on the smoothing of the contacting surfaces, the frictional moment is continuously reduced during the run-in process NOTE For the test run at 500 r/min, there is a special run-in period of 24 hours before the real test starts This runin is carried out with the lower speed 750 r/min and with the axial load Fa = 10 kN 3.9 frictional moment of the test bearing arrangement at steady-state torque, Mrb is obtained after the run-in period and is reached when the frictional moment stabilizes at a fairly constant value (variation can be 20 %) 3.10 steady-state temperature temperature, θB, obtained at the end of the run-in period 3.11 test temperature temperature, θ , measured at the outer ring of the spring-side test bearing NOTE Owing to better heat dissipation, the bearing at the drive side may be °C to °C cooler BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) 3.12 rolling element wear wear loss in weight, mw, during the stressing period due to wear caused by rolling and sliding movements in the rolling element raceway contacts and rolling element wear from cage contacts 3.13 mean rolling element wear mean rolling element wear in weight, mwm, from two tests according to this European Standard, each with two bearings, carried out in the same test rig and with lubricating grease from the same sample 3.14 combined mean rolling element wear from repeatability tests mean rolling element wear in weight, mr, from four or more tests, each with two bearings, carried out in the same test rig and with lubricating grease from the same sample 3.15 combined mean rolling element wear from reproducibility tests mean rolling element wear in weight, mR, from tests, each with two bearings, carried out with two or more tests in different laboratories and with lubricating grease from the same sample 3.16 test speed operating speed, n, of the test bearing arrangement 3.17 test load axial load, Fa, constant in magnitude and acting on the test bearings in axial direction 3.18 outlier a deviating test value that is not fulfilling the statistical criteria specified in ISO 5725-2 Symbols For the purposes of this European Standard, the following symbols apply: Ep run-in period, in hours Fa test load, in newtons Mr frictional moment of the test bearing arrangement, in newton metres Mrb frictional moment of the test bearing arrangement at steady-state, in newton metres Mrs frictional moment of the test bearing arrangement at start, in newton metres mR combined mean value of rolling element wear from tests in different laboratories for establishing reproducibility, in milligrams mr combined mean rolling element wear from tests in one test rig for establishing repeatability, in milligrams mw rolling element wear, in milligrams mwm mean value of rolling element wear from four tested bearings, in milligrams n test speed, in revolutions per minute BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Rw reproducibility limits, in milligrams rw repeatability limits, in milligrams sr repeatability standard deviation, in milligrams sR reproducibility standard deviation, in milligrams t stressing duration, in hours testing period, in hours µR permissible variation of reproducibility, in milligram µr permissible variation of repeatability, in milligram θ test temperature, in degrees Celsius θB steady-state temperature, in degrees Celsius Testing principle The testing process evaluates component wear The two tapered roller bearings installed in the test rig as testing elements are filled with a defined amount of the grease to be tested The bearings are axially loaded with the test load Fa and driven with the test speed n After a short run-in period Ep, a practically constant frictional moment, called steady-state moment Mrb, is obtained for the duration of the test The steady-state temperature θB depends on frictional energy from the bearings The steady-state temperature can be controlled by separate heating or cooling and maintained at a specific value independent of variation of bearing friction A bearing failure due to lubrication break-down causes a progressive increase of the frictional moment Mr to a multiple of the steady-state frictional moment Even if a failure does not occur during the testing period tp, the lubrication capacity of the grease may be inadequate and by that bring about moderate to severe abrasive of wear of the bearing components The resulting loss in weight of the rolling elements mw is used for assessing the wear-inhibiting capability, or in other words the lubricating ability of the lubricating grease Reagents and material Use only reagents of recognised analytical grades, e.g white spirit according to BS 245 [3] BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Test equipment1 7.1 Test rig FE8 Figure shows the basic layout of the test head for grease testing with the FE8 test rig The test head is coupled to a drive unit via the tapered end (Key 7) of the test head shaft (Key 6) The test head is supported by the drive unit via the test head shaft (Key 6) The tapered end (Key 7) is attached to a tapered bore of the driving shaft of the drive unit before starting a test and detached when the test is finished The driving shaft of the drive unit is driven directly by an electric motor or by a gear Various speeds between 7,5 and 000 r/min can be chosen The test bearings (Keys and 4) are installed in the head The bearings are axially loaded by means of Belleville springs (Key 1) The width of the spacer ring (Key 2) and the deflection characteristic of the selected springs determine the magnitude of the load and have to be calibrated according to the maintenance plan Instead of a spacer ring (Key 2) it is possible to use a load cell to bring about the correct load The test head is provided with inserted thermocouples for measuring the outer ring temperature of the bearings (Key 5) The frictional moment of the bearings is measured This is carried out by means of a force transducer (beam with strain gauges) that transmits the holding force of the housing (Key 8) to a data capture system The holding force prevents the housing from rotating due to the frictional moment from the bearings 7.2 Test bearings For the test, two tapered roller bearings 31312 are mounted in the test head NOTE Bearings of this design, specially adapted for the FE8 test are available2 New bearings are required for each test Information about suppliers can be obtained from Fachausschuss Mineralöl- und Brennstoffnormung, FAM, (technical committee for mineral oil and fuel standardization), Überseering 40, DE-22297 Hamburg, Germany Information about suppliers can be obtained from Fachausschuss Mineralöl- und Brennstoffnormung, FAM, (technical committee for mineral oil and fuel standardization), Überseering 40, DE-22297 Hamburg, Germany BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Key Belleville springs spacer ring test bearing (see 7.2) test bearing (see 7.2) thermocouple test head drive shaft tapered end of test head drive shaft position for applying the force that takes up the frictional moment from the bearings Figure — FE8 test rig head 7.3 7.3.1 Measuring equipment General Measuring and evaluation parameters are rolling element wear, friction of the test bearings and bearing temperature 7.3.2 Rolling element wear Wear of the rolling elements is determined by weighing the rolling elements prior to and immediately after the test run and following thorough cleaning 10 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) NOTE The loss in weight is determined by weighing the rolling elements on a precision balance before and after the stressing period A change of the magnetic properties, which may occur during the stressing time of steel parts, can affect the weighing result and is to be avoided The precision balance to measure the loss of weight of the rollers should be able to weigh parts up to 800 g with a scale of 0,001 g and a precision of ± 0,002 g 7.3.3 Measuring of frictional forces The frictional force of the two test bearings is taken up by a suitable transducer and recorded by a data logger By calibrating the force transducer prior to the testing at least three load steps by means of different weights, the magnitude of the frictional forces is established 7.3.4 Temperature measurement The temperature of the test bearings is measured by sensory analysis, e.g by means of thermocouples The temperature is measured at the outer ring and recorded by a suitable data logger The room temperature has to be taken into account The sensory analysis equipment has to be calibrated at established intervals Grease sampling When taking samples, the following measures shall be adopted: 1) unless otherwise specified, samples shall be taken in accordance with one of the procedures specified in EN ISO 3170 or an equivalent national standard; 2) laboratory samples shall be examined for homogeneity before taking the test portion; 3) samples shall be stored at a temperature between °C and 30 °C, for at least 24 hours, before use Testing procedure 9.1 Washing procedure All parts of the test head shall be washed and thoroughly dried before and after each test run White spirit or a similar non-aqueous solvent should be used for the washing, and the parts may be dried using clean and dry compressed air The bearings shall be disassembled before washing 9.2 Assembly First weigh the rolling elements Then the inner ring and roller set of the two test bearings are mounted on the test head shaft The two bearings are thoroughly provided with 400 ml lubricating grease For each bearing, the inner ring with rollers is given 25 ml and the outer ring raceway 25 ml grease Then the space between the bearings is filled with the remaining 300 ml of the total grease supply 9.3 Running the test During testing operation, the test head is externally cooled by a fan to obtain the operating temperatures indicated in 10.2.2 The fan is positioned such that there is a flow of cooling air around the test head During the test run, the frictional moment of the test assembly and the outer ring temperature of at least one of the bearings are recorded NOTE The environmental temperature during the test should preferably be 20 °C to 28 °C 11 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) The test is run at the speed n = 750 r/min in 500 h and the axial load Fa = 20 kN for ordinary-speed vehicles with vehicle speed ≤ 200 km/h For high-speed vehicles, with vehicle speed ≤ 300 km/h, the test is run at the speed n =1 500 r/min in 500 h and the axial load Fa = 10 kN Before starting the 500 r/min test, an initial 24 hours run-in at 750 r/min at 10 kN axial load is carried out NOTE For high-speed vehicles test speed higher than 500 r/min may be used subject to agreement between supplier and customer Wear of the rolling elements for each bearing is determined by weighing before and after the test Two tests are run for each evaluation of the result of rolling element wear, see 10.2.1 10 Evaluation 10.1 Recording The following test related information shall be recorded: 1) date of the test; 2) identity of test rig; 3) operator of test rig; 4) bearing identification numbers; 5) grease identification; 6) axial load; 7) rotational speed; 8) room temperature; 9) maximum and steady state operating temperature of the bearings; 10) type and identification of the tested lubricating grease, batch number; 11) frictional moment after 0/20/100/500 running hours; 12) rolling element wear of each bearing; 13) if any difference in appearance is shown, this should also be noted, e.g strong darkening of the lubricating grease, change in texture or different deposits 10.2 Test result 10.2.1 Rolling element wear Approval of the lubricating ability of greases is in this European Standard determined by the rolling element wear Two tests are needed for evaluating the mean rolling element wear for the four tested bearings For approval in this European Standard, the mean rolling element wear of the four tested bearings, mwm, that is the sum of the rolling element wear divided by four, shall not exceed 35 mg Each individual test result shall also fulfil the repeatability variation limits, see 11.2 These conditions are valid for the normal test speeds 750 r/min and 500 r/min, and also if higher speeds in special cases would be selected by agreement between supplier and customer 12 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) 10.2.2 Testing temperature and frictional moment During the test, the outer ring temperature is normally 40 °C to 70 °C for the test at 750 r/min and 45 °C to 95 °C for the test at 500 r/min The frictional moment normally will after run-in stabilize at a fairly constant value (different temperature and friction moment for each test condition) 11 Precision 11.1 General background The precision of the FE8 test method has been determined by a Round Robin test following the guidelines in ISO 5725-1, ISO 5725-2, ISO 5725-6 and ISO 4259 The test result is illustrated in Annex B The results gave overall general mean (grand mean) values mr and mR of 16,3 mg The results of the Round Robin test were derived from 26 participating laboratories All data has been thoroughly investigated for consistency and reliability Two outliers were found, according to ISO 5725-2, in the statistical evaluation These outliers were excluded from the final calculation For each run, the data from two bearings were reported and each laboratory has run two tests for each sample of grease To use the precision for settling a dispute or for calibration, duplicate tests on each sample are required and the mean of these four test data shall be reported and used The acceptance rolling element wear limit for approval was established to be 35 mg, see 10.2.1 When two or more tests have been performed by the same laboratory on the same sample of grease and under repeatability conditions, the repeatability variation can be applied 11.2 Repeatability The difference between results from tests carried out with the same test material, by one operator using the same apparatus within the shortest feasible time interval shall not exceed the permissible repeatability variation, µr The standard deviation for the repeatability, sr, of the Round Robin test was estimated to 5,6 mg The repeatability limits, rw, can be calculated with Equation (1) for 95 % confidence interval rw = ± 2,83 s r (1) The permissible repeatability variation is then µ r = mr ± rw (2) Confidence interval 95 % means that the permissible variation shall not be exceeded more than once in 20 tests For the Round Robin test with mr = 16,3 mg and sr, = 5,6 mg, the repeatability variation calculated with Equation (2) will be 0,5 – 32,1 mg For a test operator, the repeatability variation of test results can be calculated by means of Equation (2) The mean result of the rolling element wear from each test run shall all be within the repeatability variation limits for being considered to be acceptable In case of a test mean value found outside the repeatability limits, the result may be considered as an outlier and a re-run may be required The repeatability variation within each selected mean wear result is calculated by means of Equation (2) with the mean wear value inserted for mr For different selected cases of mean wear results, the same repeatability value rw, according to Equation (1) is used See example in Annex C 13 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) For detailed information, see ISO 4259 11.3 Reproducibility The difference between results from tests, carried out with identical test material, reported by two laboratories shall not deviate more than specified by the reproducibility variation given below more than once in 20 tests (95 % confidence interval) The reproducibility standard deviation, sR, estimated by the Round Robin test is 9,6 mg and mR is the combined mean rolling element wear of the test results from both laboratories The permissible reproducibility limits, Rw, is determined by means of Equation (3) for 95 % confidence interval R w = ± 2,83 s R (3) The permissible reproducibility variation is then µ R = mR ± R w (4) For the Round Robin test with mR = 16,3 mg and sR, = 9,6 mg, the variation limits calculated with Equation (4) will be – 44 mg When results are obtained in two laboratories and the separate mean rolling element wear mwm from each laboratory are within the variation limit values, calculated with Equation (4) with sR = 9,6 inserted, the result shall be considered as acceptable The combined mean value, mR, rather than either one of the separate rolling element wear results, mwm, shall be considered as the estimated value of the tested property In case of dispute, refer to ISO 4259, Clauses and 10 12 Test report The test report shall contain all information recorded in 10.1 and shall in addition include the following information: 1) a reference to this European Standard; 2) result of the test (with derivation of precision); 3) any agreed deviation from the specified procedure 14 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Annex A (informative) Maintenance Check the following components: 1) check thermocouples for damage, correct operation and calibration status; 2) observe cleanliness of the mounting space; 3) check test bearing raceways; 4) check tapered seatings of the coupling components – the tapered parts of test head shaft and drive shaft of the drive unit 15 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Annex B (informative) Round Robin test B.1 Result The precision of tests carried out in the FE8 test rig has been determined by a Round Robin test In this test, the resulting overall mean roller wear, from four bearings from two different tests in the same test rig, with grease from the same grease sample, was found to be 16,3 mg The repeatability standard deviation distribution, sr, was calculated to be 5,6 mg and corresponding reproducibility standard deviation, sR, was estimated to 9,6 mg The general distribution of the test data for repeatability with deviations sr and repeatability limits rw are shown in Figure B.1 and corresponding values for reproducibility in Figure B.2 B.2 Symbols in the Figures B.1 and B.2 mr combined rolling element wear from different complete (four bearing) tests in one test rig mR combined mean value of rolling element wear from bearings tested in different laboratories sr repeatability standard deviation sR reproducibility standard deviation 16 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) B.3 Test data distribution Key rolling element wear in milligrams Figure B.1 — General test data distribution for repeatability, including all samples Key rolling element wear in milligrams Figure B.2 — General test data distribution for reproducibility for all samples and laboratories 17 BS EN 14685-1:2009+A1:2010 EN 14865-1:2009+A1:2010 (E) Annex C (informative) Precision calculation examples C.1 Repeatability example Assume that four tests, carried out in the same test rig, give the rolling element mean wear values, mwm, 19 mg for the first two tests (each with two bearings) and mg from the two other tests The combined mean wear mr = (19 + 5) / = 12 mg The repeatability variation is according to Equation (2): àr = 12 2,83 ì 5,6 = – 27,8 mg The rolling element mean wear values, mwm, are both below 35 mg and both values are well within the repeatability variation limits, and the results thus accepted Assume now that the first mwm = 19 mg is the mean value of mg and 37 mg from the first two tests The repeatability variation is then for this mean value according to Equation (2): µr = 19 ± 2,83 × 5,6 = 3,2 – 34,8 mg The results mg and 37 mg can therefore both be considered as outliers, and an additional test is required to establish this C.2 Reproducibility example Assume that the mean rolling element wear, mwm, from tests with lubricating grease from the same batch is 36 mg from one laboratory and 12 mg from another The combined mean wear mR = (36 + 12) / = 24 mg The reproducibility variation is according to Equation (4): µR = 24 ± 2,83 × 9,6 = – 51,2 mg The tests fulfil the condition for reproducibility, but it is recommended to run a third single test to clarify if the result 36 mg can be reduced to an accepted value below 35 mg 18