1、BS ISO26867:2009ICS 43.040.40NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDRoad vehicles Brake lining frictionmaterials Frictionbehaviour assessmentfor automotive brakesystemsThis British Standardwas published under theauthority of the StandardsPolicy and Stra
2、tegyCommittee on 31 August2009 BSI 2009ISBN 978 0 580 60418 8Amendments/corrigenda issued since publicationDate CommentsBS ISO 26867:2009National forewordThis British Standard is the UK implementation of ISO 26867:2009.The UK participation in its preparation was entrusted to TechnicalCommittee AUE/1
3、1, Braking systems.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot conf
4、er immunityfrom legal obligations.BS ISO 26867:2009Reference numberISO 26867:2009(E)ISO 2009INTERNATIONAL STANDARD ISO26867First edition2009-07-01Road vehicles Brake lining friction materials Friction behaviour assessment for automotive brake systems Vhicules routiers Matriaux de friction pour garni
5、tures de freins valuation du comportement au frottement pour les systmes de freinage automobiles BS ISO 26867:2009ISO 26867:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unle
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10、iso.org Web www.iso.org Published in Switzerland ii ISO 2009 All rights reservedBS ISO 26867:2009ISO 26867:2009(E) ISO 2009 All rights reserved iiiContents Page Foreword. v Introduction . vi 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Symbols and abbreviated terms . 4 4.1 Sym
11、bols . 4 4.2 Abbreviated terms 6 5 Test conditions and preparation . 6 5.1 Inertia for the front axle 6 5.2 Inertia for the rear axle . 6 5.3 Test wheel load . 6 5.4 Pressure ramp rate . 6 5.5 Maximum pressure . 6 5.6 Pressure level with no power assist. 7 5.7 Sampling rate 7 5.8 Initial brake tempe
12、rature 7 5.9 Brake warm-up 7 5.10 Temperature measurement 7 5.11 Brake fluid displacement measurement. 7 5.12 Cooling air conditions 7 5.13 Cooling air velocity or volume 7 5.14 Conditioning settings for temperature and absolute humidity (humidity ratio) 7 5.15 Dynamometer rotational speed between b
13、rake applications. 8 5.16 Orientation of brake set-up 8 5.17 Direction of air concerning brake set-up . 8 5.18 Brake cooling rate. 8 5.19 Wear measurement. 8 5.20 Lateral run-out. 8 5.21 Rotor or drum condition. 8 5.22 Fade sections 8 5.23 Data collection 9 6 Test procedures 10 6.1 Test procedure fo
14、r product monitoring with no optional brake applications 10 6.2 Test procedure for product development with additional brake applications . 12 6.3 Standard friction values calculated during test procedure 14 7 Test report . 15 7.1 General. 15 7.2 Graphical report 15 7.3 Tabular data for each brake a
15、pplication. 15 7.4 Wear measurements. 15 7.5 Test conditions . 15 7.6 Cooling air conditions 15 7.7 Brake cooling rate. 16 7.8 Friction values. 16 7.9 Statistical analysis 16 Annex A (informative) Sample report for disc brakes 17 BS ISO 26867:2009ISO 26867:2009(E) iv ISO 2009 All rights reservedAnne
16、x B (informative) Histograms for instantaneous friction values. 20 Annex C (informative) Reference calculations for cooling air speed and flow 22 Bibliography . 24 BS ISO 26867:2009ISO 26867:2009(E) ISO 2009 All rights reserved vForeword ISO (the International Organization for Standardization) is a
17、worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented
18、 on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are draft
19、ed in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Stan
20、dard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 26867 was prepared b
21、y Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking systems and equipment. BS ISO 26867:2009ISO 26867:2009(E) vi ISO 2009 All rights reservedIntroduction In the process of harmonizing automotive brake system applications, the modernization of friction behaviour characterizatio
22、n is a top priority. This International Standard is intended to replace previous friction evaluation test procedures based solely on drag brake applications, which do not take into account real-life driving conditions or vehicle specific parameters. The varied conditions under which the friction mat
23、erial is evaluated ensures a wide spectrum of data, which is critical during the various phases of product life, such as product and manufacturing process development, production validation, quality control, product auditing and field issues evaluation. This International Standard is intended to be
24、used in conjunction with other applicable standards or test procedures (ISO, SAE, JIS/JASO, Federal Codes or Regulations, and other project or company-specific testing programmes) to fully assess the adequacy of a friction material for use in a certain application, market or vehicle platform. This I
25、nternational Standard does not include performance requirements related to stopping distance or braking force distribution, under different vehicle conditions of speed, temperature, tyre-to-road adhesion, loads and operating conditions of the braking system, as indicated in Federal Codes or Regulati
26、ons. This International Standard is intended as a friction evaluation inertia-dynamometer test procedure to replace previous test protocols that depend solely upon drag applications. This International Standard supports the friction assessment during the life cycle of a friction material. Friction e
27、valuation and characterization by performing drag applications, which were once a valid replacement for sample and scale testing, have now proven a limited approach. Drag applications do not correlate with real-world driving conditions, brake system characteristics or vehicle dynamics. The chemistry
28、 and structure of the transfer layers developed at the surface of the friction couple (friction lining and mating rotor or drum) and the resulting coefficient of friction varies as a function of changing characteristics, e.g. sliding speed, surface and bulk temperatures, braking pressure, braking en
29、ergy and surface topology. During any given brake application, the braking energy varies as a result of the mass distribution and dynamic mass transfer on the vehicle. This is directly related to the vehicles wheelbase, centre of gravity and vehicle height, which in itself can directly influence the
30、 friction material behaviour. The same brake lining or part number, when used on different vehicles, can perform differently depending upon its load, velocity, operating temperature, application force and work history. Modern testing equipment enables friction formulators, process designers, applica
31、tions engineers and manufacturing personnel to obtain a wide and detailed characterization on the different levels of friction witnessed by the brake lining or pad during various brake conditions. This International Standard is designed to evaluate the friction behaviour under a wide array of drivin
32、g speeds, brake temperatures, brake pressure and deceleration levels. This new procedure provides the following benefits: a standard method for determining friction characteristics during early screening, benchmarking; development or production monitoring; the use of average by distance torque and p
33、ressure calculations; instantaneous friction statistics; an estimation of stopping distance using mean fully developed deceleration; controlled and recorded environmental conditions. BS ISO 26867:2009INTERNATIONAL STANDARD ISO 26867:2009(E) ISO 2009 All rights reserved 1Road vehicles Brake lining fr
34、iction materials Friction behaviour assessment for automotive brake systems 1 Scope This International Standard describes a test procedure for assessing the influence of pressure, temperature, and linear speed on the coefficient of friction of a given friction material in combination with a specific
35、 mating component (rotor or drum). This International Standard is intended for use when comparing friction materials under the same conditions, or when controlling friction behaviour against a specification or certain performance limits. In order to take into account the different types of dynamomet
36、er cooling systems and to ensure repeatable temperature increments, the brake temperature is the control item during the fade sections. The types of brakes and discs used will vary according to individual projects. Production verification testing can use the results from this test in conjunction wit
37、h a statistical process control system as part of a quality assurance plan. The specific project or programme will detail the applicable limits and assessment criteria. This International Standard also allows for additional sections and brake applications that can prove useful during product develop
38、ment testing. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 611, Roa
39、d vehicles Braking of automotive vehicles and their trailers Vocabulary ISO 15484, Road vehicles Brake lining friction materials Product definition and quality assurance UNECE Regulation No.13-H, Uniform provisions concerning the approval of passenger cars with regard to braking 3 Terms and definiti
40、ons For the purposes of this document, the terms and definitions given in ISO 611, ISO 15484, UNECE Regulation No.13-H and the following apply. 3.1 friction value average by distance of all instantaneous friction values for disc brakes or for drum brakes after the brake reaches 95 % of the set point
41、 value (pressure or deceleration) until it falls below 95 % of the set point level NOTE 1 For disc brakes, the friction value is obtained using Equation (1) (see definition 3.2). NOTE 2 For drum brakes, the friction value is obtained using Equation (2) (see definition 3.3). NOTE 3 The average by dis
42、tance friction value from each individual brake application is the value referenced as “friction value” in Table 4. BS ISO 26867:2009ISO 26867:2009(E) 2 ISO 2009 All rights reserved3.2 instantaneous friction value * disc brake ratio of instantaneous output torque to instantaneous input torque at any
43、 specific point in time, calculated as follows: ()5d,brakethreshold p eff10*2Mpp A r= (1) where Md,brakeis the measured torque; p is the applied pressure; pthresholdis the threshold pressure or minimum pressure required to develop braking torque; Apis the piston area; reffis the brake effective radi
44、us; is the efficiency 3.3 instantaneous effectiveness value C* drum brake ratio instantaneous output torque to instantaneous input torque at any specific point in time, calculated as follows: ()5d,brakethreshold p eff10*MCpp A r =(2) where Md,brakeis the measured torque; p is the applied pressure; p
45、thresholdis the threshold pressure or minimum pressure required to develop braking torque; Apis the piston area; reffis the brake effective radius; is the efficiency 3.4 mean fully developed deceleration dmfddeceleration calculated as follows: ()22bemfdeb25,92vvds s=(3) BS ISO 26867:2009ISO 26867:20
46、09(E) ISO 2009 All rights reserved 3where veis the release speed; vbis the linear speed at 0,8vp; vpis the prescribed or braking speed for the brake application; seis the calculated distance travelled between vpand ve; sbis the calculated distance travelled between vpand vbNOTE Equation (3) applies
47、only when the release speed veis lower than 0,5vp. The dmfdcalculation for brake applications with vehigher than 0,5vpprovides a very short range of data to perform a useful calculation. For certain brake applications, 0,8vpcan be lower than the release speed. 3.5 step sequence number to label the d
48、ifferent sections (3.6) during the test and ensure the test is conducted in the prescribed order 3.6 section group of similar brake applications under similar conditions or following a specific logic NOTE 1 The brake applications can be stops (3.7) or snubs (3.8). NOTE 2 The specific logic can be in
49、creasing brake pressure, increasing initial speed, or increasing brake temperature. 3.7 stop brake stop brake application where the brake slows down the test inertia until the equivalent linear speed is 0,5 km/h or less 3.8 snub brake snub brake application where the brake slows down the test inertia to an equivalent linear speed above 5 km/h 3.9 characteristic section series of brake snubs (3.8) at moderate speed, brake pressure and temperature, in order to assess how the friction leve
