BRITISH STANDARD AUTOMOBILE SERIES BS AU 180 4 1982 ISO 6313 1980 Brake linings — Part 4 Method for determining effects of heat on dimensions and form of disc brake pads [ISO title Road vehicles — Bra[.]
BRITISH STANDARD AUTOMOBILE SERIES BS AU 80-4:1 982 ISO 631 3:1 980 Brake linings — Part 4: Method for determining effects of heat on dimensions and form of disc brake pads [ISO title: Road vehicles — Brake linings — Effects of heat on dimensions and form of disc brake pads — Test procedure] UD C 62 1 - 597 6: 620 BS AU 80-4:1 982 National foreword This British Standard has been prepared under the direction of the Automobile Road vehicles — Brake linings — Effects of heat on dimensions and form of disc brake pads — Test procedure” published by the International Organization for Standards Committee and is identical with ISO 631 3: 980 “ Standardization (ISO) Terminology and conventions The text of the International Standard has been approved as suitable for publication as a British Standard without deviation Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following The comma has been used throughout as a decimal marker In British Standards it is current practice to use a full point on the baseline as the decimal marker Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard” Cross-reference At present there is no corresponding British Standard for ISO 61 However, it is intended to publish a related standard at a future date The technical committee has reviewed the provisions of ISO 61 and has decided that they are acceptable for use in conj unction with this standard A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible 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, pages i and ii, This British Standard, having been prepared under the direction of the Automobile pages to and a back cover This standard has been updated (see copyright date) and may have had Standards Committee, amendments incorporated This will be indicated in the amendment table on was published under the the inside front cover authority of the Board of BSI and comes into effect on 31 March 982 © BSI 02- 2000 The following BSI references relate to the work on this standard: Committee reference AUE/1 Draft for comment 78/80969 DC ISBN 80 36 X Amendments issued since publication Amd No Date of issue Comments BS AU 80-4:1 982 Contents Page National foreword © BSI 02 - 000 Inside front cover Introduction Scope and field of application 1 Reference 1 Symbols and designations Sampling and conditioning Test rig Test method Presentation of results Test report Figure — Principal dimensions and determination of reference points Figure — Example of test rig i ii blank BS AU 80-4:1 982 — certain dimensions of the lining outline when Introduction their variation may involve a misfunctioning of This International Standard describes a method for measuring dimensional changes of disc brake pads under the influence of heat At the same time, it gives an indication of the resistance of whole disc brake pads to heat transfer in the direction of applied pressures According to the design of the test rig, either one or two disc brake pads are required for testing An extension of this International Standard for drum brake linings has the brake This International Standard applies to disc brake pads for road vehicles Their dimensions should not exceed 80 mm in depth, 20 mm in width and 20 mm in thickness, being of integral moulded or bonded type, and the backing plate of solid type Reference still to be prepared ISO 61 , Dimensional changes and the temperatures trailers —Term inolo gy Braking o f m otor vehicles and their recorded in accordance with this test method in the zone of contact of the operating forces are measured on disc brake pads whose rubbing surface is pressed against a heated plate subj ected to a given temperature- time programme Symbols and designations For general definitions, see ISO 61 Symbol d Scope and field of application This International Standard specifies a combined Mean thickness of specimen pad m (see clause ) d Dimensions, possibly concerned, of the Ai lining outline (see clause ) method of measuring disc brake pads to determine their dimensional changes in relation to d Dimensions, possibly concerned, of the Bi temperature and their resistance to heat transfer The dimensions concerned are: — thickness dimension; Designation lining outline at ambient temperature % d after test (see clause ) i Changes of the possibly concerned dimensions of the lining outline (see clause ) Figure — Principal dimensions and determination of reference points © BSI 02- 2000 BS AU 80-4:1 982 Sampling and conditioning d) a dial gauge (4) measuring displacement from the pad backing plate or intermediate plate Take the samples from stock through the device ensuring the compressive Before placing the pads into the test rig, rub them down on both sides with emery paper (grain size No 20) so as to remove the coat of paint from the force 5.2 Heating capacity backing plate and to render the rubbing surface The heating source shall be capable of bringing the itself smooth and free from unevenness plate to a temperature of 400 °C in ± 0, In Remove any friction material from spigot holes in the backing plate to a depth sufficient to avoid influencing the test results In the case of disc brake pads fitted with a thin flexible anti- noise strip on the back face of the backing plate, prepare this strip in the same way as the friction material to give a good contact surface certain cases, especially with a view to utilization of tested brake linings on a given vehicle type, it may be necessary to adopt a plate temperature above 400 °C and to reach this temperature in less than 5.3 Measuring equipment Temperature is measured centrally in the heating Determine two reference points as shown in plate by means of a sheathed thermocouple in a hole Figure , and measure the thickness of the disc running parallel to, and mm from, the contact brake pad at the reference points to an accuracy surface (see Figure 2) of 0, 01 mm The mean value of these two measurements is designated d m Measure the dimensions, if concerned, of the lining outline These values are designated In the case of disc brake pads equipped with anti- noise strips, a mm thick 80 × 00 mm d Ai Drill a mm diameter hole in the side of the lining down to one of the reference points described above This hole shall be parallel to the rubbing surface at a distance of mm, and is used to house a sheathed thermocouple Drill a mm diameter hole in the lining backing plate parallel to and same depth as the hole described above, to house a sheathed thermocouple In the case of disc brake pads equipped with anti- noise strips, this hole is omitted Linings exceeding the limits of 20 × 80 × 20 mm shall be reduced to this size by cutting with a parting- off disc and/or by surface grinding Test rig The test rig is composed of a rigid, electrically heated steel plate, 80 mm high, 70 mm wide and 40 mm thick, with devices for clamping the thermal conductive plate is placed between the pad and the clamping device for the measurement of heat transfer The temperature measurement on this plate is taken by means of a sheathed thermocouple which is situated in a hole drilled to the centre of the plate (see Figure 2) The block for clamping the disc brake pad is provided with a device capable of applying a force range of 20 to 200 N Fixed on the same side the displacement measuring devices shall measure the displacement from the pad backing plate or intermediate plate Test method Place the disc brake pad prepared in accordance with clause between the heater plate and clamping block, with the rubbing surface towards the heater plate, and clamped with a pad surface pressure of about 20 kPa (0, 02 N/mm ) In the case of disc pads equipped with anti- noise strips, insert the intermediate plate between the pad and the clamping block The dial gauges or brake pad and for the measuring equipment inductive displacement transducers are mounted The test rig may be designed for two brake pads and set to zero As an example, Figure shows a test rig, which Switch on the heating at a setting which will result meets the requirements in a final temperature of 400 ° C at the end of The rig consists of (see Figure 2): a) a clamping block (1 ) provided with a piston of 48 mm diameter moving easily in the block; b) various coil springs (2) ensuring by deflection a heating period NOTE In certain cases, especially with a view to utilization of tested brake linings on a given vehicle type it may be necessary that this final temperature be above 400 ° C and reached in less than the force through the piston; c) a screw thread with adj uster nut (3) to deflect the springs; © BSI 02- 2000 BS AU 80-4:1 982 Figure — Example of test rig °C , According to the equip ment us ed, meas ure the As soon as the heater p late reaches 50 variations in the p ad thicknes s and the temp erature the heat s ource on again and rep eat the p rocess of the heating p late, the friction material and the describ ed ab ove No readj ustment s hall take p lace s witch p ad b acking p late or intermediate p late during the under any circums tances at the b eginning of the heating and cooling p eriod second heating p eriod If the measurements are not taken b y means of a recorder, thes e s hall b e read at °C heater p late temp erature b etween At the end of the tes t, meas ure the dimensions , if intervals of concerned, of the lining outline at room °C temp erature These values s hall b e des ignated and the d Bi final temp erature After the final temp erature has b een reached, the heat source is switched off, and the cooling p eriod b egins during which the s ys tem is allowed to cool naturally, without any cooling air b lown on to the heater p late © BS I - 00 BS AU 80-4:1 982 Presentation of results Test report 7.1 If a recorder is used, the traces shall be suitab ly The test report shall contain following particulars: identified so that the recording of change of pad thickness, heater plate temperature, pad temperature and pad backing plate or intermediate plate temperature can b e unambiguously related to a) quality designation, type and supplier of the disc b rake pad; b ) mean thickness d m at the beginning of the test; the appropriate factors If an x, y , y , y , plotter is c) maximum values of relative change of lining used, the direction of the ab scissae is controlled b y thickness with the corresponding temperatures the heater plate temperature and test period; 7.2 If the values are read off, pad and pad backing d) change of lining thickness at highest plate or intermediate plate temperature and change temperature for the first and the second test of lining thickness shall be plotted on millimetre period; paper against heater plate temperature, again e) residual change of thickness and dimensions, if making sure that the curves are suitab ly identified concerned, of the lining outline at the end of the Finally, if need be, calculate the differences test when cooled down to room temperature; %d d i = Bi – d Ai f) pad b acking plate or intermediate plate temperature at highest heater plate temperature for the first and second test period; g) appearance of the disc brake pads after the test, noting especially any formation of cracks and bub bles, peeling or chipping of friction material and detachment from the b acking plate © BSI 02 - 000 blank BS AU 80-4:1 982 ISO 631 3:1 980 BSI — British Standards Institution BS I is the indep endent national b ody res p ons ib le for p rep aring Britis h S tandards It p res ents the UK view on s tandards in E urop e and at the international level It is incorp orated b y Royal C harter Revisions Britis h S tandards are up dated b y amendment or revis ion Us ers of Britis h S tandards should make s ure that they p oss es s the latest amendments or editions It is the constant aim of BS I to imp rove the quality of our p roducts and services We would b e grateful if anyone finding an inaccuracy or amb iguity while us ing this Britis h S tandard would inform the S ecretary of the technical committee res p ons ib le, the identity of which can b e found on the inside front cover Tel: 02 89 96 90 00 Fax: 02 89 96 40 BS I offers memb ers an individual up dating s ervice called PLUS which ens ures that s ub s crib ers automatically receive the lates t editions of s tandards Buying standards O rders for all BS I, international and foreign s tandards p ub lications s hould b e addres s ed to C us tomer S ervices Tel: 899 00 Fax: 899 7001 In res p ons e to orders for international standards , it is BS I p olicy to sup p ly the BS I imp lementation of thos e that have b een p ub lis hed as Britis h S tandards, unless otherwis e requested Information on standards BS I p rovides a wide range of information on national, E urop ean and international standards through its Lib rary and its Technical H elp to E xp orters S ervice Various BS I electronic information s ervices are also availab le which give details on all its p roducts and s ervices C ontact the Information C entre Tel: 02 89 96 71 1 Fax: 02 89 96 048 S ub s crib ing memb ers of BS I are kep t up to date with s tandards develop ments and receive sub s tantial discounts on the p urchase p rice of s tandards For details of thes e and other b enefits contact Memb ership Adminis tration Tel: 02 89 96 70 02 Fax: 02 89 96 00 Copyright C op yright s ub s is ts in all BS I p ub lications BS I als o holds the cop yright, in the UK, of the p ub lications of the international s tandardization b odies E xcep t as p ermitted under the C op yright, D es igns and Patents Act 988 no extract may b e rep roduced, s tored in a retrieval s ystem or transmitted in any form or b y any means – electronic, p hotocop ying, recording or otherwis e – without p rior written p ermis s ion from BS I This does not p reclude the free us e, in the cours e of imp lementing the standard, of necess ary details such as s ymb ols, and size, typ e or grade designations If thes e details are to b e used for any other p urp os e than imp lementation then the p rior written p ermiss ion of BS I must b e ob tained If p ermis sion is granted, the terms may include royalty p ayments or a licensing agreement D etails and advice can b e ob tained from the C op yright Manager BS I 89 C his wick H igh Road London W4 4AL Tel: 02 89 96 70