1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 15222:2011Truck and bus tyres Methodfor measuring relative wet gripperformance Loaded newtyresBS ISO 15222:2011 BRITISH STANDARDNational forewordThis British Standard is t
2、he UK implementation of ISO 15222:2011.The UK participation in its preparation was entrusted to TechnicalCommittee AUE/4, Tyres and wheels for motor vehicles.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include
3、all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 69321 2ICS 43.080.01; 83.160.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards P
4、olicy and Strategy Committee on 31 August 2011.Amendments issued since publicationDate Text affectedBS ISO 15222:2011Reference numberISO 15222:2011(E)ISO 2011INTERNATIONAL STANDARD ISO15222First edition2011-08-15Truck and bus tyres Method for measuring relative wet grip performance Loaded new tyres
5、Pneumatiques pour camions et autobus Mthode de mesure de ladhrence relative sur revtement mouill Pneumatiques neufs en charge BS ISO 15222:2011ISO 15222:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or uti
6、lized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax
7、 + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedBS ISO 15222:2011ISO 15222:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Normative references 1 3 Terms and definitions . 2 3.1 General terms and definit
8、ions 2 3.2 Terms and definitions for the vehicle testing method described in Clause 6 2 3.3 Terms and definitions for the trailer or tyre test vehicle testing method described in Clause 7 2 4 Methods for measuring wet grip 3 5 General test conditions. 3 5.1 Track characteristics . 3 5.2 Wetting cond
9、itions 4 5.3 Atmospheric conditions . 4 5.4 Reference tyres 4 6 Measurement of tyre wet grip on a standard vehicle 5 6.1 Principle . 5 6.2 Equipment 5 6.3 Conditioning of the test track 6 6.4 Measurement requirements for test speeds . 6 6.5 Tyres and rims . 6 6.6 Procedure . 7 6.7 Processing of meas
10、urement results . 8 6.8 Wet grip performance comparison between a candidate tyre and a reference tyre using a control tyre . 10 7 Test method using a trailer or a tyre test vehicle 11 7.1 Principle . 11 7.2 Apparatus . 12 7.3 Instrumentation . 12 7.4 Selection and preparation of test tyres . 13 7.5
11、Preparation of the apparatus and the test track 14 7.6 General test conditions. 14 7.7 Procedure . 14 7.8 Processing of measurement results . 15 Annex A (informative) Example test reports of wet grip index 17 Bibliography 19 BS ISO 15222:2011ISO 15222:2011(E) iv ISO 2011 All rights reservedForeword
12、ISO (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 committees. Each member body interested in a subject for which a technical
13、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 International Electrotechnical Commission (IEC) on all matters of elect
14、rotechnical standardization. International Standards are drafted 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
15、member bodies for voting. Publication as an International Standard 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 ident
16、ifying any or all such patent rights. ISO 15222 was prepared by Technical Committee ISO/TC 31, Tyres, rims and valves, Subcommittee SC 4, Truck and bus tyres and rims. BS ISO 15222:2011INTERNATIONAL STANDARD ISO 15222:2011(E) ISO 2011 All rights reserved 1Truck and bus tyres Method for measuring rel
17、ative wet grip performance Loaded new tyres 1 Scope This International Standard specifies the method for measuring relative wet grip braking performance index to a reference under loaded conditions for new tyres for use on commercial vehicles on a wet-paved surface. The methods developed in this Int
18、ernational Standard are meant to reduce the variability. The use of a reference tyre is necessary to limit the variability of the testing method procedures. This International Standard applies to all truck and bus tyres (commercial vehicle tyres). 2 Normative references The following referenced docu
19、ments 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 4209-1, Truck and bus tyres and rims (metric series) Part 1: Tyres EN 1303
20、6-1:2010, Road and airfield surface characteristics Test methods Part 1: Measurement of pavement surface macrotexture depth using a volumetric patch technique ASTM E303:2008, Standard Test Method for Measuring Surface Frictional Properties Using the British Pendulum Tester ASTM E501, Standard Specif
21、ication for Standard Rib Tire for Pavement Skid-Resistance Tests ASTM E965, Standard Test Method for Measuring Pavement Macrotexture Depth Using a Volumetric Technique ASTM E1136, Standard Specification for P195/75R14 Radial Standard Reference Test Tire ASTM F2870, Standard Specification for 315/70R
22、22.5 154/150L Radial Truck Standard Reference Test Tire ASTM F2871, Standard Specification for 245/70R19.5 136/134M Radial Truck Standard Reference Test Tire ASTM F2872, Standard Specification for 225/75R16C 116/114S M+S Radial Light Truck Standard Reference Test Tire BS ISO 15222:2011ISO 15222:2011
23、(E) 2 ISO 2011 All rights reserved3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 General terms and definitions 3.1.1 test run single pass of a loaded tyre over a given test surface 3.1.2 candidate tyre “T” (set) test tyre (or a test tyre set
24、) that is part of an evaluation programme 3.1.3 reference tyre “R” (set) standard reference test tyre special test tyre (or a test tyre set) that is used as a benchmark in an evaluation programme NOTE These tyres usually have carefully controlled design features to minimize variation. 3.2 Terms and
25、definitions for the vehicle testing method described in Clause 6 3.2.1 control tyre “C” (set) tyre (set) that is part of an evaluation programme NOTE It is an intermediate set of tyres which is used when the candidate tyre and the reference tyre cannot be directly compared on the same vehicle. 3.3 T
26、erms and definitions for the trailer or tyre test vehicle testing method described in Clause 7 3.3.1 braking force of a tyre longitudinal force, expressed in newtons, resulting from braking torque application 3.3.2 braking force coefficient of a tyre BFC ratio of braking force to vertical load 3.3.3
27、 peak braking force coefficient of a tyre peakmaximum value of tyre braking force coefficient that occurs prior to wheel lockup as the braking torque is progressively increased 3.3.4 lockup of a wheel condition of a wheel in which its rotational velocity about the wheel spin axis is zero and it is p
28、revented from rotating in the presence of applied wheel torque 3.3.5 vertical load normal (Z-direction) reaction of the tyre on the road BS ISO 15222:2011ISO 15222:2011(E) ISO 2011 All rights reserved 33.3.6 trailer or tyre test vehicle special purpose tyre evaluation vehicle which has instruments t
29、o measure the longitudinal force on one tyre during braking 3.3.7 coupling (hitch) height height when measured perpendicularly from the centre of the articulation point of the trailer towing coupling or hitch to the ground, when the towing vehicle and trailer are coupled together NOTE The vehicle an
30、d trailer shall be standing on level pavement surface in its test mode complete with the appropriate tyre(s) to be used in the particular test. 4 Methods for measuring wet grip Relative wet grip braking performance for loaded commercial vehicle new tyres travelling straight ahead on a wet, paved sur
31、face can be measured by one of the following methods: a vehicle method consisting of testing a set of tyres mounted on a standard vehicle; a test method using a trailer or a tyre test vehicle equipped with one or several test tyre(s). 5 General test conditions 5.1 Track characteristics 5.1.1 General
32、 The surface shall be a dense asphalt surface with a uniform gradient of not more than 2 % and shall not deviate more than 6 mm when tested with a 3 m straight edge. The test surface shall have a pavement of uniform age, composition, and wear. The test surface shall be free of loose material or fore
33、ign deposits. The maximum chipping size shall be from 8 mm to 13 mm. The sand depth measured as specified in EN 13036-1:2010 and ASTM E965, shall be (0,7 0,3) mm. In order to verify the wetted frictional properties of the surface, one of the methods in 5.1.2 or 5.1.3 shall be used. 5.1.2 British Pen
34、dulum Number (BPN) method The averaged BPN British Pendulum Tester method as specified in ASTM E303 using the Pad as specified in ASTM E501 shall be (50 10) BPN after temperature correction. BPN shall be corrected by the wetted road surface temperature. Unless temperature correction recommendations
35、are indicated by the British pendulum manufacturer, Equation (1) can be used: 2Temperature correction 0,001 8 0,34 6,1TT (1)where “T” is the wetted road surface temperature in degrees Celsius. BS ISO 15222:2011ISO 15222:2011(E) 4 ISO 2011 All rights reservedEffects of slider pad wear: the pad should
36、 be removed for maximum wear when the wear on the striking edge of the slider reaches 3,2 mm in the plane of the slider or 1,6 mm vertical to it in accordance with ASTM E303:2008, 5.2.2 and Figure 3. Check the test track testing surface BPN consistency for the measurement of wet grip on a standard v
37、ehicle. To decrease the dispersion of test results, the BPN values of the track should not vary over the entire stopping distance. The operation shall be repeated five times at each point of the BPN measurement. Measurements for BPN shall be taken every 10 m on the braking lane and the coefficient o
38、f variation of the BPN averages shall not exceed 10 %. 5.1.3 Standard Reference Test Tyre (SRTT) method The average peak braking coefficient (peak,ave) of the ASTM E1136 reference tyre (see Clause 7) shall be (0,7 0,1) at 65 km/h. For the trailer method, testing is run in such a way that braking occ
39、urs within 10 m of where the surface was examined. The average peak braking coefficient (peak,ave) of the ASTM E1136 reference tyre shall be corrected by the wetted road surface temperature according to Equation (2): Temperature correction 0,003 5 20T (2)where “T” is the wetted road surface temperat
40、ure in degrees Celsius. 5.2 Wetting conditions The surface may be wetted from the track-side or by a wetting system incorporated into the test vehicle or the trailer. If “external watering” is used, water the test surface at least half an hour prior to testing in order to equalize the surface temper
41、ature and water temperature. External watering should be supplied continuously throughout testing. For the whole testing area, the water depth shall be between 0,5 mm and 2 mm. 5.3 Atmospheric conditions The wind conditions shall not interfere with wetting of the surface (wind-shields are allowed).
42、The ambient and the wetted surface temperatures shall be between 5 C and 35 C and shall not vary during the test by more than 10 C. 5.4 Reference tyres In order to cover the range of the tyre sizes fitting the commercial vehicles, three SRTT sizes shall be used to measure the relative wet index: SRT
43、T 315/70R22.5 LI=154/150, ASTM F2870 SRTT 245/70R19.5 LI=136/134, ASTM F2871 SRTT 225/75R16C LI=116/114, ASTM F2872 The three SRTT sizes shall be used to measure the relative wet index as shown in Table 1. BS ISO 15222:2011ISO 15222:2011(E) ISO 2011 All rights reserved 5Table 1 Measurement of the re
44、lative wet index SRTT for rim codes 17 2 Families FAMILY Rim Code 17 NARROW SNominal17 WIDE SNominal 285 mm SRTT 245/70R19.5 LI=136/134 SRTT 315/70R22.5 LI=154/150 SRTT for Rim Codes Rear axle load; The rear axle shall be indifferently fitted with 2 or 4 tyres. Conf.3: Rear axle load Front axle load
45、 1,8. 6.5.4 Tyre inflation pressure For a vertical load higher or equal to 75 % of the load capacity of the tyre, the test inflation pressure ptshall be calculated using Equation (3): QppQ1, 2 5ttrr(3) where pris inflation pressure marked on the sidewall. If pris not marked on the sidewall, refer to
46、 the specified pressure in applicable tyre standards manuals corresponding to maximum load capacity for single applications; Qtis the static test load of the tyre; Qris the maximum mass associated with the load capacity index of the tyre. For a vertical load lower than 75 % of the load capacity of t
47、he tyre, the test inflation pressure, ptshall be calculated using Equation (4): pp p 1, 2 5tr0,75 (0,7)r(4) where pris inflation pressure marked on the sidewall. NOTE If pris not marked on the sidewall, refer to the specified pressure in applicable tyre standards manuals corresponding to maximum loa
48、d capacity for single applications. Check the tyre pressure just prior to testing at ambient temperature. 6.6 Procedure First, mount the set of reference tyres on the vehicle. Accelerate the vehicle in the starting zone up to (65 2) km/h. The brakes shall always be activated at the same place on the
49、 track, with a longitudinal tolerance of 5 m and transverse tolerance of 0,5 m. According to the type of transmission, two cases are possible. BS ISO 15222:2011ISO 15222:2011(E) 8 ISO 2011 All rights reserveda) manual transmission: As soon as the driver is in the measuring zone and has reached (65 2) km/h, release the clutch and depress the brake pedal sharply, holding it down as long as necessary to perform the measurement; b) automatic transmission: As soo
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