1、BRITISH STANDARD BS 6419:1983 ISO 7464:1983 Method for Measurement of drawbar pull of earth-moving machinery ISO title: Earth-moving machinery Method of test for the measurement of drawbar pull UDC 624.132:621.878/.879:629.11.013.1.07BS6419:1983 This British Standard, having been prepared under the
2、directionof the Road EngineeringStandards Committee, was published underthe authority of the BoardofBSI and comes into effect on 30November1983 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference RDB/21 Draft for comment 82/10074 DC ISBN 0 580 13485 7 Co
3、mmittees responsible for this British Standard The preparation of this British Standard was entrusted by the Road Engineering Standards Committee (RDB/-) to Technical Committee RDB/21 upon which the following bodies were represented: Associated Offices Technical Committee Construction Industry Train
4、ing Board Construction Plant-hire Association Department of Industry Federation of Civil Engineering Contractors Federation of Manufacturers of Construction Equipment and Cranes Health and Safety Executive Institution of Civil Engineers Institution of Highway Engineers Ministry of Defence National C
5、oal Board Trades Union Congress Amendments issued since publication Amd. No. Date of issue CommentsBS6419:1983 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Field of application 1 3 Definitions 1 4 Test site 1 5 Apparatus 2 6 Preparation for t
6、est 2 7 Procedure 3 8 Test results 4 Figure 1 Typical curves 7 Figure 2 Example of test train for drawbar pull 8 Table 1 Recommended format for reporting results 5 Table 2 Drawbar pull test data sheet 6BS6419:1983 ii BSI 12-1999 National foreword This British Standard has been prepared under the dir
7、ection of the Road Engineering Standards Committee and is identical with ISO7464:1983 “Earth-moving machinery Method of test for the measurement of drawbar pull” published by the International Organization for Standardization (ISO). ISO 7464 was produced as a result of international discussion in wh
8、ich the UK took an active part. 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 dra
9、wn especially to the following. The comma has been used 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
10、”. 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 compris
11、es a front cover, an inside front cover, pages i and ii, pages1 to 8 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 cover.BS6419:1983 BSI 12-1999 1 1 Scope This Internat
12、ional Standard specifies a test method to measure the drawbar pull performance of self-propelled earth-moving machinery and their combination with mounted or trailed equipment, with or without payload. It covers the following criteria measured against travel speed: drawbar pull, drawbar power, and w
13、heel or track slip. 2 Field of application This International Standard applies to all types of self-propelled earth-moving machines except excavators. 3 Definitions For the purposes of this International Standard, the following definitions apply: 3.1 drawbar/hitch point the part of the test machine
14、used for the attachment of the dynamometer car 3.2 drawbar pull the horizontal towing force exerted at the drawbar/hitch point, expressed in kilonewtons (kN) 3.3 drawbar power the towing power transmitted through the hitch point, expressed in kilowatts (kW). It is calculated as the product of travel
15、 speed, in metres per second(m/s) and drawbar pull, in kilonewtons (kN) 3.4 travel speed the actual machine velocity expressed in metres per second (m/s) or kilometres per hour (km/h) 3.5 rated engine speed the engine speed at which the manufacturer specifies it should develop rated power, expressed
16、 in revolutions per minute (r/min) 3.6 fast idle engine speed the engine speed when running off-load at full throttle, expressed in revolutions per minute (r/min) 3.7 test time the time taken to cover the test distance, or duration of the test run, expressed in seconds (s) 3.8 test distance the dist
17、ance travelled by the test machine during the test time, expressed in metres (m) 3.9 wheel or track slip the difference of drive wheel revolutions (loaded) and drive wheel revolutions (unloaded) over the same distance and expressed as a percentage of the loaded revolutions 3.10 dynamometer car a mac
18、hine which can apply a controlled, sustained load to the machine under test. It shall provide, as a minimum, instrumentation to measure drawbar pull, actual distance travelled, drive wheel revolutions, engine output shaft speed (r/min) and time of test runs 3.11 machine mass the mass of the machine
19、as tested. It shall include the operator, a full tank of fuel, and all fluid compartments at their specified level; expressed in kilograms (kg) 3.12 tyre pressure air pressure in the machine tyres, as tested, expressed in kilopascals (kPa) 3.13 drive wheel revolutions the number of revolutions that
20、the drive wheels or sprockets make for a specified test distance or time 3.14 ambient air temperature/relative humidity wet bulb and dry bulb readings which are recorded during the test, expressed in degrees Celsius ( C) 3.15 barometric pressure measured during period of test, expressed in kilopasca
21、ls (kPa) 4 Test site The test track shall be a straight, level surface prepared to provide desired conditions of traction with a minimum of rolling resistance.BS6419:1983 2 BSI 12-1999 4.1 Recommended minimum length The recommended minimum length is100m, with approaches of such length that speed and
22、 load can be stabilized before entering the test section. Turning areas shall be provided at both ends of the track with sufficient room for the test train to turn easily (seeFigure 2). 4.2 Grade The grade shall be less than0,5%. If testing is conducted on a site with a grade more than0,5%, runs sha
23、ll be taken in both directions and the results averaged. The crown slope from centreline to shoulder shall be less than3%. 4.3 Surface 4.3.1 Rubber-tyred machines For machines equipped with rubber tyres, the surface shall be, in order of preference: 4.3.1.1 Concrete The surface shall have a uniform
24、rough texture. It should have a minimum of expansion joints. Sealing material in the expansion joints shall be maintained flush or below the surface. It shall be dry and clean. 4.3.1.2 Bituminous These materials are generally known as asphalt or asphaltic concrete. 4.3.2 Crawlers and steel-wheeled m
25、achines For crawlers or steel-wheeled machines, test courses of earth shall be used. These earthen surfaces shall be well packed and substantially free of loose material. This requires a soil that is cohesive when properly moistened and compacted. Scarifying, watering, grading and compacting equipme
26、nt is needed for track preparation. 4.3.3 Alternative surfaces The test may be conducted on any other type of surface if required for specific test purposes. The nature of the surface shall be reported. 5 Apparatus (SeeFigure 2 for examples of apparatus used.) 5.1 Dynamometer car, or towed load, con
27、trollable to maintain within specified limits either: a) speed of engine, shaft output of infinitely variable drive, or drive wheels of the machine being tested; or b) drawbar pull. It shall be capable of testing the machine to full drawbar performance without exceeding its own safe operating limits
28、. 5.2 Means to measure and record the following: 6 Preparation for test 6.1 Measure and/or adjust engine performance to the manufacturers specification on an engine or PTO dynamometer. 6.2 Carry out a service check on the machine prior to testing to ensure that: a) all mechanical adjustments are as
29、recommended by the manufacturer (engine speeds, brakes, clutches, etc.); b) fuel, lubricants, and coolant are as specified by the manufacturer. 6.3 Add payload, ballast and/or attachments as required. 6.4 Adjust tyre pressures as specified by the manufacturer (see6.8). 6.5 Weigh the machine and obta
30、in total mass and distribution on drive wheels with the operator in position on the seat and a full fuel tank. 6.6 Connect the machine to the dynomometer car and hook up all instrumentation. The height of the drawbar/hitch point shall be set as recommended by the manufacturer. Adjust the hitch on th
31、e dynamometer car to maintain a horizontal line of pull. If the machine is normally used for towing, attachment shall be at the towing hitch or drawbar. Ground engaging machines such as graders or scrapers should have the load attached at a height no more than100mm above ground level. Accuracy Time
32、0,2 s Distance 0,5 % Pull 1,0 % Engine speed (r/min) 1,0 % Output shaft of infinitely variable drives 1,0 % Drive wheel or sprocket revolutions 0,5 % Machine mass 1,5 % of massmeasured Tyre pressure 3,0 % Grouser height or tread depth 1,0 mm Temperature Wet and dry bulb 1 C Barometric pressure 0,35
33、kPaBS6419:1983 BSI 12-1999 3 6.7 Operate the test train sufficiently to determine that all systems are operating properly. 6.8 Prepare the drive tyres of a rubber-tyred machine by driving on the test track and applying a partial load (1/2to3/4 of maximum) while operating in first or second gear. Obs
34、erve the wear pattern on the lugs of the tyres. If contact is not occurring across the full width of the tread face, lower the tyre pressure. Caution: Do not reduce pressure below the low limit for the actual weight being carried on each tyre see machine manufacturers recommendations. Tyre tread or
35、track grouser wear should not exceed50% of the new lug/grouser depth. 6.9 The track tension should be adjusted to manufacturers specification. 6.10 Determine the “free roll” or no tractive pull revolutions of the drive wheels or sprockets over a measured distance by driving the machine in the lowest
36、 gear or ratio with the engine at a low running speed, with no directional (steering) corrections, for a distance of at least50m. Determine the “free roll” counts. 6.11 Record general data as shown inTable 1. 7 Procedure 7.1 Prior to recording test data, the machine shall be operated until engine, t
37、ransmission and final drive fluid temperatures are in the operating range. During the test runs, the engine controls shall be set at a position where the engine develops maximum power. 7.2 While travelling the test distance in the desired gear (or ratio of infinitely variable drive) and with the tow
38、ed load adjusted to maintain the average speed of engine, drive wheels or sprockets at specified revolutions per minute (r/min) for each specific test run, record: a) drawbar pull; b) time; c) distance; d) engine speed (r/min); e) output shaft revolutions per minute (r/min) of infinitely variable dr
39、ive; f) number of revolutions of each drive axle. As an alternative procedure, the drawbar pull for each run may be controlled and held as constant as possible. The same data are recorded. The distance and axle revolution counters may be controlled automatically by an electronic timer. If so, the du
40、ration of each test run is determined by time rather than distance. The time and distance of recorded test runs should be sufficient to achieve the desired accuracy. The average of two runs (one in each direction) should be used in reporting machine performance at each selected speed or pull. There
41、should be a minimum of steering during the recorded runs. Revolutions of the drive wheels on wheeled machines shall not vary from each other by more than3%. Revolutions of the drive sprockets on track machines shall not vary from each other by more than2%. During any recorded run the instantaneous s
42、peed of engine or of the output shaft of infinitely variable drive shall not vary more than3% from the specified speed. The average speed for any one run shall not vary more than 3% from the specified speed and the average for the two selected runs shall not vary more than0,5% from the specified spe
43、ed. 7.3 A series of runs are taken in each gear, all at wide open (full) throttle. The load is varied from minimum to maximum until the drive system peak torque is reached or up to the point of15% wheel slip or7% track slip. 7.4 On machines with torque converters or infinitely variable drive systems
44、, if stall pull values are to be measured, it may be necessary to add more ballast to the machine to prevent wheel slip before the stall is obtained. 7.5 Tests should be limited to travel speeds that can be safely obtained under the given conditions, usually less than20km/h. Extra precautions must b
45、e observed for high speed runs. 7.6 The following calculations may be made: 7.6.1 The slip, s, may be calculated, as a percentage, from the formula: where N is the distance count (bike wheel); f is the constant, the ratio of drive wheel to bike wheel count i.e.f =r/n, where r is the free roll drive
46、wheel count, and n is the free roll bike count; R is the drive wheel revolution count (average of right and left).BS6419:1983 4 BSI 12-1999 7.6.2 The travel speed, V, may be calculated from the following formula: where N is the distance count (bike wheel); n is the free roll bike count; d is the fre
47、e roll distance, in metres; t is the time to travel test distance, in seconds (to the nearest0,1s); c is the constant, distance per count of bike wheeli.e.c = d/n. 7.6.3 The drawbar power, P, is calculated from the formula: P = VL where L is the drawbar pull, in kilonewtons, averaged for either time
48、 or distance. 8 Test results 8.1 Test results shall be presented as shown in the sample data sheets ofTable 1 andTable 2. 8.2 Curves should be plotted from the results of the series of test runs. Typical curves are shown inFigure 1. 8.3 The drawbar power recorded shall be the power developed at the
49、hitch point including wheel slip; however, the measured wheel slip shall be stated.BS6419:1983 BSI 12-1999 5 Table 1 Recommended format for reporting results Drawbar pull according to ISO 7464 Summary of test results Gear Drawbar max pull kN Travel speed km/h % Slip Drawbar max power kW Travel speed km/h or engine speed r/min % Slip Drawbar power rated speed a kW Weather Temperature Barometric pressure kPa Wet bulb C Dry bulb C a Advertised engine power.BS 6419:1983 6 BSI 12-1999 Table 2 Drawbar pull
