1、BRITISH STANDARD AUTOMOBILE SERIES BS AU 180-4:1982 ISO6313:1980 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 UDC 629.11-597.6:620
2、.1BSAU180-4:1982 This BritishStandard, having been prepared under the directionof the Automobile Standards Committee, waspublished under the authorityof the Board of BSI and comes into effect on 31March1982 BSI02-2000 The following BSI references relate to the work on this standard: Committee refere
3、nce AUE/11 Draft for comment78/80969 DC ISBN 0 580 12536 X National foreword This BritishStandard has been prepared under the direction of the Automobile Standards Committee and is identical with ISO6313:1980 “Road vehicles Brake linings Effects of heat on dimensions and form of disc brake pads Test
4、 procedure” published by the International 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
5、 those used in BritishStandards; attention is especially drawn to the following. The comma has been used throughout as a decimal marker. In BritishStandards it is current practice to use a full point on the baseline asthedecimal marker. Wherever the words “International Standard” appear, referring t
6、o this standard, they should be read as “BritishStandard”. Cross-reference. At present there is no corresponding BritishStandard for ISO611. However, it is intended to publish a related standard at a future date. The technical committee has reviewed the provisions of ISO611 and has decided that they
7、 are acceptable for use in conjunction 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 l
8、egal 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 date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front
9、cover. Amendments issued since publication Amd. No. Date of issue CommentsBSAU180-4:1982 BSI 02-2000 i Contents Page National foreword Inside front cover 0 Introduction 1 1 Scope and field of application 1 2 Reference 1 3 Symbols and designations 1 4 Sampling and conditioning 2 5 Test rig 2 6 Test m
10、ethod 2 7 Presentation of results 4 8 Test report 4 Figure 1 Principal dimensions and determination of reference points 1 Figure 2 Example of test rig 3ii blankBSAU180-4:1982 BSI 02-2000 1 0 Introduction This International Standard describes a method for measuring dimensional changes of disc brake p
11、ads 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 Inter
12、national Standard for drum brake linings has still to be prepared. Dimensional changes and the temperatures 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 subjected to
13、 a given temperature-time programme. 1 Scope and field of application This International Standard specifies a combined method of measuring disc brake pads to determine their dimensional changes in relation to temperature and their resistance to heat transfer. The dimensions concerned are: thickness
14、dimension; certain dimensions of the lining outline when their variation may involve a misfunctioning of the brake. This International Standard applies to disc brake pads for road vehicles. Their dimensions should not exceed80mm in depth,120mm in width and20mm in thickness, being of integral moulded
15、 or bonded type, and the backing plate of solid type. 2 Reference ISO611, Braking of motor vehicles and their trailersTerminology. 3 Symbols and designations For general definitions, seeISO611. Symbol Designation d m d Ai d Bi %d i Mean thickness of specimen pad (seeclause4) Dimensions, possibly con
16、cerned, of the lining outline (seeclause4) Dimensions, possibly concerned, of the lining outline at ambient temperature after test (seeclause6) Changes of the possibly concerned dimensions of the lining outline (seeclause7) Figure 1 Principal dimensions and determination of reference pointsBSAU180-4
17、:1982 2 BSI 02-2000 4 Sampling and conditioning Take the samples from stock. Before placing the pads into the test rig, rub them down on both sides with emery paper (grain size No.120) so as to remove the coat of paint from the backing plate and to render the rubbing surface itself smooth and free f
18、rom unevenness. 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 th
19、e friction material to give a good contact surface. Determine two reference points as shown in Figure 1, and measure the thickness of the disc brake pad at the reference points to an accuracy of0,01mm. The mean value of these two measurements is designated d m . Measure the dimensions, if concerned,
20、 of the lining outline. These values are designated d Ai . Drill a2mm 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 of5mm, and is used to house a sheathed thermocouple. Drill a2mm diameter
21、 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 of120 80 20mm shall be reduced to this size by cutting with a
22、 parting-off disc and/or by surface grinding. 5 Test rig 5.1 The test rig is composed of a rigid, electrically heated steel plate,80mm high,170mm wide and40mm thick, with devices for clamping the brake pad and for the measuring equipment. The test rig may be designed for two brake pads. As an exampl
23、e, Figure 2 shows a test rig, which meets the requirements. The rig consists of (seeFigure 2): a) a clamping block(1) provided with a piston of48mm diameter moving easily in the block; b) various coil springs(2) ensuring by deflection the force through the piston; c) a screw thread with adjuster nut
24、(3) to deflect the springs; d) a dial gauge(4) measuring displacement from the pad backing plate or intermediate plate through the device ensuring the compressive force. 5.2 Heating capacity The heating source shall be capable of bringing the plate to a temperature of400 C in10 0,5min. In certain ca
25、ses, especially with a view to utilization of tested brake linings on a given vehicle type, it may be necessary to adopt a plate temperature above400 C and to reach this temperature in lessthan10min. 5.3 Measuring equipment Temperature is measured centrally in the heating plate by means of a sheathe
26、d thermocouple in a hole running parallel to, and5mm from, the contact surface (seeFigure 2). In the case of disc brake pads equipped with anti-noise strips, a4mm thick80 100mm thermal conductive plate is placed between the pad and the clamping device for the measurement of heat transfer. The temper
27、ature 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 (seeFigure 2). The block for clamping the disc brake pad is provided with a device capable of applying a force range of20 to200N. Fixed on the same side the dis
28、placement measuring devices shall measure the displacement from the pad backing plate or intermediate plate. 6 Test method Place the disc brake pad prepared in accordance with clause4 between the heater plate and clamping block, with the rubbing surface towards the heater plate, and clamped with a p
29、ad surface pressure of about20kPa(0,02N/mm 2 ). 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 inductive displacement transducers are mounted and set to zero. Switch on the heating at a setting which
30、will result in a final temperature of400 C at the end of a10min heating period. NOTEIn 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 above400 C and reached in lessthan10min.BSAU180-4:1982 BSI 02
31、-2000 3 According to the equipment used, measure the variations in the pad thickness and the temperature of the heating plate, the friction material and the pad backing plate or intermediate plate during the heating and cooling period. If the measurements are not taken by means of a recorder, these
32、shall be read at25 C intervals of heater plate temperature between50 C and the final temperature. After the final temperature has been reached, the heat source is switched off, and the cooling period begins during which the system is allowed to cool naturally, without any cooling air blown on to the
33、 heater plate. As soon as the heater plate reaches50 C, switch the heat source on again and repeat the process described above. No readjustment shall take place under any circumstances at the beginning of the second heating period. At the end of the test, measure the dimensions, if concerned, of the
34、 lining outline at room temperature. These values shall be designated d Bi . Figure 2 Example of test rigBSAU180-4:1982 4 BSI 02-2000 7 Presentation of results 7.1 If a recorder is used, the traces shall be suitably identified so that the recording of change of pad thickness, heater plate temperatur
35、e, pad temperature and pad backing plate or intermediate plate temperature can be unambiguously related to the appropriate factors. If anx,y 1 ,y 2 ,y 3 , plotter is used, the direction of the abscissae is controlled by the heater plate temperature. 7.2 If the values are read off, pad and pad backin
36、g plate or intermediate plate temperature and change of lining thickness shall be plotted on millimetre paper against heater plate temperature, again making sure that the curves are suitably identified. Finally, if need be, calculate the differences %d i = d Bi d Ai 8 Test report The test report sha
37、ll contain following particulars: a) quality designation, type and supplier of the disc brake pad; b) mean thickness d mat the beginning of the test; c) maximum values of relative change of lining thickness with the corresponding temperatures and test period; d) change of lining thickness at highest
38、 temperature for the first and the second test period; e) residual change of thickness and dimensions, if concerned, of the lining outline at the end of the test when cooled down to room temperature; f) pad backing plate or intermediate plate temperature at highest heater plate temperature for the f
39、irst and second test period; g) appearance of the disc brake pads after the test, noting especially any formation of cracks and bubbles, peeling or chipping of friction material and detachment from the backing plate.blankBS AU 180-4:1982 ISO6313:1980 BSI 389 Chiswick High Road London W4 4AL BSIBriti
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