1、BSI Standards PublicationBS ISO 11749:2014Belt drive V-ribbed belts forthe automotive industry Fatigue testBS ISO 11749:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 11749:2014.The UK participation in its preparation was entrusted to TechnicalCommittee M
2、CE/10, Belts 43.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 28 February 2014.Amendments issued since publicationDate Text affectedBS ISO 11749:2014 ISO 2
3、014Belt drive V-ribbed belts for the automotive industry Fatigue testTransmissions par courroies Courroies stries pour la construction automobile Essai de fatigueINTERNATIONAL STANDARDISO11749Second edition2014-01-15Reference numberISO 11749:2014(E)BS ISO 11749:2014ISO 11749:2014(E)ii ISO 2014 All r
4、ights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. 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 pr
5、ior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandB
6、S ISO 11749:2014ISO 11749:2014(E) ISO 2014 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Principle 14 Apparatus . 15 Test room conditions . 26 Test method . 36.1 Test conditions 36.2 Procedure 37 Test report . 5Bibliography .11BS ISO 11749:2014ISO 11749:2014(E)F
7、orewordISO (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 tec
8、hnical 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 o
9、f 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 different types of ISO documents should be noted. This document
10、 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 shall not be held responsible for identifying any or all such p
11、atent 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 document is information given for the convenience of users and does no
12、t 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 (TBT) see the following URL: Foreword - Supplementary information
13、The committee responsible for this document is ISO/TC 41, Pulleys and belts (including veebelts), Subcommittee SC 1, Friction.This second edition cancels and replaces the first edition (ISO 11749:1995), which has been technically revised. It also incorporates Amendment ISO 11749:1995/Amd.1:2003.iv I
14、SO 2014 All rights reservedBS ISO 11749:2014INTERNATIONAL STANDARD ISO 11749:2014(E)Belt drive V-ribbed belts for the automotive industry Fatigue test1 ScopeThis International Standard specifies a dynamic test method for the quality control of V-ribbed belts (PK profile) which are used predominantly
15、 for accessory drive applications in the automotive industry.The dimensional characteristics of the belts and of corresponding pulleys are the subject of ISO 9981.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for
16、 its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 683-1, Heat-treatable steels, alloy steels and free-cutting steels Part 1: Non-alloy steels for quenching and tempering
17、ISO 6508-1, Metallic materials Rockwell hardness test Part 1: Test method (scales A, B, C, D, E, F, G, H, K, N, T)ISO 9981:1998, Belt drives Pulleys and V-ribbed belts for the automotive industry PK profile: Dimensions3 PrincipleDetermination of the performance of a belt under specified conditions o
18、n a two-, three-, or four-pulley test machine as described in Clause 4.The shortest V-ribbed belt which can be tested on the four-pulley test machine (see Figure 1) is approximately 1 000 mm. Belts with lengths between 800 mm and 1 000 mm inclusive can be tested on the three-pulley test machine (see
19、 Figure 2). Shorter belts should be tested on the two-pulley test machine (see Figure 3) as described in 6.2.1.2.A number of conditions shall be agreed between the manufacturer and user, including the power to be transmitted, the minimum acceptable life, in hours, and the number of times the belt ca
20、n be retensioned.Belt failure occurs when the belt no longer satisfies the agreed conditions.4 Apparatus4.1 Dynamic test machine, of robust design so that all components withstand, with virtually no deflection, the stress to which they are subjected.The test machine shall consist of the following (s
21、ee Figures 1, 2, and 3).4.1.1 Driving pulley, and suitable mechanism for driving it.4.1.2 Driven pulley, to which a suitable power-absorption unit is connected (4.1.3).4.1.3 Power-absorption unit, accurate and capable of calibration. ISO 2014 All rights reserved 1BS ISO 11749:2014ISO 11749:2014(E)4.
22、1.4 Temperature control system.4.1.5 Reverse bending idler pulley, only for four-pulley test machine (see Figure 1).4.1.6 Device through which tension may be applied to the belta) in the case of the three- or four-pulley test machine layout, an idler and tensioner pulley (see Figures 1 and 2), orb)
23、in the case of the two-pulley test machine layout, a movable pulley (see Figure 3).4.1.7 Means of determining belt slip, to an accuracy of 0,1 %. The layout of the pulley and the direction of rotation are shown in Figures 1, 2, and 3.In order to accommodate different lengths, the position of relevan
24、t driving and driven members, the position of the idler pulley and its support (in the case of the three-pulley test machine), and the position of the reverse bending idler pulley (in the case of the four-pulley test machine) shall be adjustable so that the test layout of the pulleys is attainable f
25、or each belt length.So that the tension can be satisfactorily applied to the belt, and in order to allow for belt stretch, the idler pulley and its bearing assembly shall be free to slide, as necessary, in the support bracket along the line of application of the tensioning force.For the four-pulley
26、test machine in such a case, the line of action of the tensioning force shall bisect the belt layout at the idler pulley and at the reverse bending idler pulley, and shall lie in the plane through the centre of the pulleys (see Figure 1).For the three-pulley test machine in such a case, the line of
27、action of the tensioning force shall bisect the belt layout at the idler pulley, shall pass through the axis centre of the idler pulley, and shall lie in the plane through the centre of the idler pulley (see Figure 2).The two-pulley test machine shall be constructed so that one of the units (driven
28、or driving) can be moved to accommodate belt lengths of up to 800 mm. A method of locking the movable unit in position for a given tension in the belt shall be provided. So that the tension can be satisfactorily applied to the belt, and in order to allow for belt stretch, the line of action of the t
29、ensioning force shall pass through the axis centre of the driven and driving pulleys and shall lie in the plane through the centre of the same pulleys (see Figure 3).4.2 Test pulleys, made from steel, as defined in ISO 683-1, with a surface hardness of 55 HRC, conforming to ISO 6508-1. The pulley gr
30、oove shall have a surface roughness such that the arithmetical mean deviation of the profile Ra is lower than 0,8 m.The characteristics of the test pulleys are given in Figure 1 and the dimensions are given in Table 1 of ISO 9981:1998.5 Test room conditionsThe test temperature shall bea) in a test r
31、oom, at an ambient temperature between 18 C and 32 C (the mean ambient temperature for the duration of the test shall be given with the test result and the atmosphere in the vicinity of the test drive shall be free of draughts from sources other than the belt drive itself), orb) in a thermostaticall
32、y controlled enclosure, a high temperature of (120 5) C, orc) in a thermostatically controlled enclosure, a high temperature of (85 5) C.2 ISO 2014 All rights reservedBS ISO 11749:2014ISO 11749:2014(E)6 Test method6.1 Test conditionsThe rotational frequency of the driving pulley shall be 4 900 min1t
33、o within 2 %. The power transmitted is fixed, in kilowatts, for a belt with three to five ribs, and shall be agreed between the manufacturer and user.The driver pulley speed, in revolutions per minute, shall be used in the torque load calculation, and the torque load shall be kept constant without c
34、ompensation for loss of driven pulley speed resulting from belt slippage.The torque load, M, is given by Formula (1)M = pNs9 549 (1)whereM is the torque load, in newton metres;Psis the specified power, in kilowatts;N is the driver speed, in rotations per minute.The test equipment shall be maintained
35、 so as to minimize parasitic loads due to bearing losses, lubricants, etc.In the case of the three- or four-pulley test machine, the belt-tensioning force, F, in newtons, applied to the idler pulley, and in the case of the two-pulley test machine that applied to the driven unit, shall be such thatF
36、= k Ps(2)wherek = 60 N/kW, in the case of the three- or four-pulley test machine;k = 110 N/kW, in the case of the two-pulley test machine.EXAMPLE For 10,3 kW, F = 618 N: for one belt with six ribs = 105 N/rib (in the case of the three- or four-pulley test).6.2 Procedure6.2.1 Preparation6.2.1.1 Three
37、- or four-pulley test machineMethod A: After mounting the belt on the pulleys, apply the specified belt-tensioning force (see 6.1) to the idler pulley and, leaving the idler pulley support bracket free to move in its slide, bring the drive up to the specified rotational frequency (see 6.1). Then app
38、ly the relevant load to the driven pulley as quickly as possible. Run the drive under these conditions for 5 min 15 s, not including the starting and stopping time. Stop the machine and leave it to stand for at least 10 min.Then turn the drive manually for several revolutions of the belt and immedia
39、tely lock the idler pulley support bracket in position. ISO 2014 All rights reserved 3BS ISO 11749:2014ISO 11749:2014(E)Method B: After mounting the belt on the pulleys, apply the specified belt-tensioning force (see 6.1) to the idler pulley, leaving the idler pulley support bracket free to move in
40、its slide. Then turn the drive manually for several revolutions of the belt and immediately lock the idler pulley support bracket in position.6.2.1.2 Two-pulley test machineUse the same procedure as in 6.2.1.1 with the movable unit taking the place of the idler pulley support.6.2.2 TestStart (re-sta
41、rt in the case of method A) the machine, bring the drive up to the specified rotational frequency, apply the test load to the driven pulley, and measure the slip between the driving and driven pulleys.The drive shall run continuously under these conditions until either the belt fails or the addition
42、al slip g exceeds by 4 % the slip measured initially.The additional slip g, expressed as a percentage, is given by Formula (3):g = (io if) 100 (3)whereinNooo= (4)andinNfff= (5)wherenois the initial rotational speed of the driven shaft;nfis the final rotational speed of the driven shaft;Nois the init
43、ial rotational speed of the driving shaft;Nfis the final rotational speed of the driving shaft.All rotational speeds shall be measured under the test load.6.2.3 RetensioningIf the additional belt slip reaches 4 % before belt failure, stop the machine and leave it to stand for at least 20 min. In the
44、 case of the three- or four-pulley test machine, unlock the idler support bracket, apply the test tension to the belt, turn the drive manually for two or three revolutions of the belt, re-lock the idler support bracket in position, as described in 6.2.1, and repeat the test specified in 6.2.2.Repeat
45、 this procedure whenever the additional slip reaches 4 % before failure, until the belt fails.4 ISO 2014 All rights reservedBS ISO 11749:2014ISO 11749:2014(E)7 Test reportThe test report shall include at least the following information:a) a reference to this International Standard (i.e. ISO 11749);b
46、) identification of the belt tested;c) the type of machine used (if necessary, the effective diameter of the idler pulley or the outside diameter of the reverse bending idler pulley);d) the method used (A or B);e) the number of running hours under test to satisfy the agreed conditions;f) the transmi
47、tted power and the number of ribs;g) the number of times and the running hours at which the belt was retensioned;h) the mean ambient temperature during the test;i) the date of the test. ISO 2014 All rights reserved 5BS ISO 11749:2014ISO 11749:2014(E)Key1 driven pulley (power-absorption unit)2 idler
48、pulley, set in slide3 reverse bending idler pulley4 direction of adjustment of driven pulley5 direction of rotation6 belt-tensioning force applied to the idler pulley7 direction of adjustment of idler pulley assembly and its supportNOTE Equal (=), the angle as shown by this figure, is specified for
49、the initial test layout and may change slightly with retensioning during the course of the test.Figure 1 Four-pulley test machine layout6 ISO 2014 All rights reservedBS ISO 11749:2014ISO 11749:2014(E)Key1 driven pulley (power-absorption unit)2 idler pulley, set in slide3 direction of adjustment of driven pulley4 direction of rotation5 belt-tensioning force applied to the idler pulley6 direction of adjustment of idler pulley assembly and its supporta45 is specified for the initial test layout and may change
