1、BRITISH STANDARD AUTOMOBILE SERIES BSAU 222:1988 ISO7629:1987 Method of evaluating surface and material flaws of disc brake pads after testing ISO title: Road vehicles Brake linings Disc brake pads Evaluation of surface and material flaws after testing UDC 629.11597.6:620.1:001.818+.004.64BSAU222:19
2、88 This BritishStandard, having been prepared under the directionof the Automobile Standards Committee, was published under the authority ofthe Board of BSI and comes into effect on 29January1988 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference AUE/11
3、 Draft for comment 84/78305 DC ISBN 0 580 16361 X Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Automobile Standards Committee (AUE/-) to Technical Committee AUE/11, upon which the following bodies were represented: Automobile Associatio
4、n British Fluid Power Association British Friction Materials Council Department of Transport Freight Transport Association London Transport Executive Motor Industry Research Association National Caravan Council Ltd. Society of Motor Manufacturers and Traders Transport and General Workers Union Amend
5、ments issued since publication Amd. No. Date of issue CommentsBSAU222:1988 BSI 02-2000 i Contents Page Committees responsible Inside front cover National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 Identification of defects 1 3 Measuring equipment 1 4 Measurement method 1 5 Exp
6、ression of results 1 Figure 1 Example of crack (type I flaw) 2 Figure 2 Example of edge flaking (type II flaw) 2 Figure 3 Example of blistering or pitting (type III flaw) 3 Figure 4 Example of lining separation from support and material lamina separation (type IV flaw) 3 Figure 5 Centring of the gri
7、d 4BSAU222:1988 ii BSI 02-2000 National foreword The BritishStandard has been prepared under the direction of the Automobile Standards Committee and is identical with ISO7629:1987 “Road vehicles Brake linings Disc brake pads Evaluation of surface and material flaws after testing”, published by the I
8、nternational Organization for Standardization (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a BritishStandard without deviation. Some terminology and certain conventions are not identical with those used in BritishStandard
9、s; attention is drawn especially to the following. Wherever the words “International Standard” appear referring to this standard, they should be read as “BritishStandard”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are respon
10、sible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4 and a back cover. This standard has been updated (see copyright d
11、ate) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BSAU222:1988 BSI 02-2000 1 0 Introduction Disc brake pads may show damage after being subjected to vehicle or laboratory tests. This International Standard has the purpose of specif
12、ying a method of describing some of this damage. 1 Scope and field of application This International Standard identifies the types of flaws of surface and material after testing of disc brake pads, and specifies the method of measuring these flaws and of setting out the results. This International S
13、tandard applies to disc brake pads intended for fitting to the brakes of road vehicles. 2 Identification of defects The presence of a flaw is decided only if it is detectable with the naked eye. Flaws to be considered are of four types: Type I Cracks (seeFigure 1) Type II Edge flaking (seeFigure 2)
14、Type III Blistering and pitting (seeFigure 3) Type IV Material separation from the support or material lamina separation (seeFigure 4) 3 Measuring equipment Transparent millimetric grid of sufficient area to cover the whole area on which defects are to be measured (seeFigure 5). 4 Measurement method
15、 4.1 Preliminary measurements 4.1.1 On the lining, prior to testing, measure and record: a) the lining height measured on the lining median line, H, in millimetres (seeFigure 1), or, for non-symmetrical shapes, the maximum height; b) the friction surface area, A 0 , in square millimetres. 4.1.2 Dete
16、rmine a reference point A, located at the middle of height H (seeFigure 5). 4.2 Measurement of flaws 4.2.1 Flaws of type1(seeFigure 1) Measure the length, l, of each crack. Position the millimetric grid on point A, as illustrated inFigure 5. Count the cracks within the10mm 10mm area which has the gr
17、eatest density of cracks. All cracks partially crossing the area are to be included. 4.2.2 Flaws of types II and III (seeFigure 2 andFigure 3) Place the millimetric grid on the work surface. Determine the area of each flaw with the naked eye. NOTEFor simplicity, edge flaking can be characterized bya
18、 b (seeFigure 2). 4.2.3 Flaws of type IV (seeFigure 4) Measure the length, L. 5 Expression of results 5.1 Cracks (type I) 5.1.1 Calculate, as a percentage of the lining heightH, and record: a) length of the longest crack; b) sum of all crack lengths. 5.1.2 Record the greatest number of cracks observ
19、ed per100mm 2 . 5.2 Edge flaking (type II), blistering and pitting (type III) Add all these flaws (types II and III). Calculate the total as a percentage of the surface area A 0 , and record: a) area of the biggest flaw; b) sum of all flaw areas. 5.3 Material separation from support and material lam
20、ina separation (type IV) Calculate, as a percentage of the lining height, H, and record: a) longest separation length; b) sum of all separation lengths.BSAU222:1988 2 BSI 02-2000 Figure 1 Example of crack (type I flaw) Figure 2 Example of edge flaking (type II flaw)BSAU222:1988 BSI 02-2000 3 Figure
21、3 Example of blistering or pitting (type III flaw) Figure 4 Example of lining separation from support and material lamina separation (type IV flaw)BSAU222:1988 4 BSI 02-2000 Figure 5 Centring of the gridblankBSAU 222:1988 ISO7629:1987 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInsti
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