1、BSI Standards PublicationBS ISO 789-3:2015Agricultural tractors TestproceduresPart 3: Turning and clearance diametersBS ISO 789-3:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 789-3:2015. Itsupersedes BS 6347-3:1983 which is withdrawn.The UK participatio
2、n in its preparation was entrusted to TechnicalCommittee AGE/6, Agricultural tractors and forestry machinery.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users
3、are responsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 79529 9ICS 65.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theS
4、tandards Policy and Strategy Committee on 30 September 2015.Amendments issued since publicationDate Text affectedBS ISO 789-3:2015 ISO 2015Agricultural tractors Test procedures Part 3: Turning and clearance diametersTracteurs agricoles Mthodes dessai Partie 3: Diamtres de braquage et de dgagementINT
5、ERNATIONAL STANDARDISO789-3Third edition2015-09-01Reference numberISO 789-3:2015(E)BS ISO 789-3:2015ISO 789-3:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be repro
6、duced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester
7、.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 789-3:2015ISO 789-3:2015(E)Foreword iv1 Scope . 12 Terms and definitions . 13 Apparatus . 54 General requirements . 54.1 Test area 54.2 Tracto
8、r test requirements . 54.2.1 Tire and wheel equipment 54.2.2 Track (tread) setting . 54.2.3 Other settings . 55 Procedure. 65.1 Right-hand turn, without brakes . 65.1.1 Direct measurement . 65.1.2 Alternate GPS method . 65.2 Left-hand turn, without brakes . 65.3 Right-hand turn, with brakes . 75.4 L
9、eft-hand turn, with brakes . 76 Test report 10Annex A (informative) Specimen test report 11 ISO 2015 All rights reserved iiiContents PageBS ISO 789-3:2015ISO 789-3:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO memb
10、er 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 technical committee has been established has the right to be represented on that committee. International organizations, government
11、al 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 of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance a
12、re 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 was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is
13、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 patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or
14、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 not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assess
15、ment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 23, Tractors and machinery for agriculture and forestry, Subcommittee 2, C
16、ommon tests.This third edition cancels and replaces the second edition (ISO 789-3:1993), which has been technically revised.ISO 789 consists of the following parts, under the general title Agricultural tractors Test procedures: Part 1: Power tests for power take-off Part 2: Rear three-point linkage
17、lifting capacity Part 3: Turning and clearance diameters Part 4: Measurement of exhaust smoke Part 5: Partial power PT0 Non-mechanically transmitted power Part 6: Centre of gravity Part 7: Axle power determination Part 8: Engine air cleaner Part 9: Power tests for drawbar Part 11: Steering capabilit
18、y of wheeled tractors Part 12: Low temperature startingISO/OECD 789 consists of the following parts, under the general title Agricultural tractors Test procedures: Part 10: Hydraulic power at tractor/implement interfaceiv ISO 2015 All rights reservedBS ISO 789-3:2015INTERNATIONAL STANDARD ISO 789-3:
19、2015(E)Agricultural tractors Test procedures Part 3: Turning and clearance diameters1 ScopeThis part of ISO 789 specifies a method of determining the turning and clearance diameters of wheeled agricultural tractors.It applies to wheeled agricultural tractors having at least two axles fitted with pne
20、umatic tyres.2 Terms and definitionsFor the purpose of this document, the following terms and definitions apply.2.1agricultural tractorself-propelled agricultural vehicle having at least two axles and wheels, or endless tracks, particularly designed to pull agricultural trailers and to pull, push, c
21、arry and operate implements used for agricultural work (including forestry work), which may be provided with detachable loading platformNote 1 to entry: The agricultural vehicle has a maximum design speed of not less than 6 km/h and may be equipped with one or more seats.SOURCE: ISO 12934:2013, 3.12
22、.2tracktreaddistance at ground level between two vertical planes passing through the centreline of ground contact of the tires parallel to the median plane of the tractor with the wheels in the straight ahead positionNote 1 to entry: In the case of dual wheels, it is the distance at ground level bet
23、ween two planes passing through the centreline of the dual wheels.Note 2 to entry: See Figure 1. ISO 2015 All rights reserved 1BS ISO 789-3:2015ISO 789-3:2015(E)Figure 1 Track (tread) of the wheeled tractor2.3wheelbasehorizontal distance between the two vertical planes passing through the rotational
24、 centrelines of the wheels, where one plane is for the front wheels and the other for the rear wheelsNote 1 to entry: In the case of a tractor equipped with a rear tandem, it is the distance between two vertical planes passing through the centres of the front wheel and the vertical plane midway betw
25、een the wheel centres of the two axles of the tandem.Note 2 to entry: See Figure 2.2 ISO 2015 All rights reservedBS ISO 789-3:2015ISO 789-3:2015(E)Figure 2 Wheelbase of the wheeled tractor2.4turning diameterdiameter of the circular path described by the centre of tire contact with the surface of the
26、 test site of the wheel describing the largest circle when the tractor is executing its sharpest practicable turn under the test conditions described in Clause 5Note 1 to entry: See Figure 3.2.5clearance diameterdiameter of the smallest circle which will enclose the outermost points of projection of
27、 the tractor and its equipment while executing its sharpest practicable turnNote 1 to entry: See Figure 3. ISO 2015 All rights reserved 3BS ISO 789-3:2015ISO 789-3:2015(E)Figure 3 Tractor turning configurations4 ISO 2015 All rights reservedBS ISO 789-3:2015ISO 789-3:2015(E)3 Apparatus3.1 Tape measur
28、e, of length greater than the turning and clearance diameters to be measured, having a tolerance within 0,5 %.3.2 Plumb-line, if required, for measuring clearance diameters.3.3 GPS equipment for alternate test, corrected GPS having a measurement accuracy sufficient to produce a linear measurement to
29、lerance of 0,5 %.4 General requirements4.1 Test areaThe test area shall be a compacted or paved dry surface affording good tire adhesion, capable of displaying legible markings, and resistant to defacement by turning machines. The test surface shall be visually flat, with no more than 3 % grade in a
30、ny direction.In selecting the test area used for GPS measurement, take into consideration the effects of obstructions (e.g. tall buildings, trees, etc.) on GPS accuracy.4.2 Tractor test requirements4.2.1 Tire and wheel equipmentThe tractor to be tested shall be in its operating state, and the attach
31、ments with which it is equipped and their positions shall be noted.The tire, wheel and fender equipment shall be that commonly used in the country for which the tractor is intended, i.e. as specified by the manufacturer, and shall be stated in the test report. Generally, dual wheeled tractors or tra
32、ctors with added ballast should not be tested unless it is the only specification presented by the manufacturer. Tire pressures, tractor ballast and use of duals on front or rear shall be recorded in the test report. If steering and/or axle oscillation stops and fenders are part of standard equipmen
33、t, then these shall be positioned according to the manufacturers instructions.4.2.2 Track (tread) settingA track (tread) setting of 1 500 mm 25 mm shall be used. If this is not possible, the nearest setting specified by the manufacturer shall be used. Additional measurement may be made at other trac
34、k settings specified by the manufacturer. Front and rear track settings shall be as nearly as possible the same and shall be recorded.4.2.3 Other settings4.2.3.1 Tractors which have all wheels steerable, or which incorporate devices for disconnecting either or both axles, shall be tested in each ope
35、rating condition in which the tractor is intended to be used.Results shall be recorded for each operating condition.4.2.3.2 Tractors which have more than one powered axle, and which have devices for disconnecting the power to any of the axles, shall be tested in each operating condition in which the
36、 tractor is intended to be used.Results shall be recorded for each operating condition. ISO 2015 All rights reserved 5BS ISO 789-3:2015ISO 789-3:2015(E)5 Procedure5.1 Right-hand turn, without brakes5.1.1 Direct measurement5.1.1.1 Drive the tractor slowly forward while making its sharpest possible ri
37、ght-hand turn, that is, with the steering kept on full right-hand lock, at a speed not exceeding 2 km/h for at least one complete turn, until it is established that the minimum turning circle is being described.5.1.1.2 Continue to drive the tractor slowly forward on the same lock for a further compl
38、ete turn, at a speed not exceeding 2 km/h. At short regular intervals around the turn, mark on the ground those points coinciding with the centre of the tire-to-ground contact area of the outermost wheel. Make the marks immediately behind this contact area and determine the position of each mark by
39、visually projecting vertically downwards from the centre of the tire tread width at points on the tire circumference situated as close as possible to the ground.The marking may be done with or without stopping the tractor. The broken circle formed by the marks on the ground is the turning circle.5.1
40、.1.3 During the turn described in 5.1.1.2, stop the tractor and drop a plumb-line (3.2) to the ground from the outermost point of the tractor (that is from the point of the tractor describing the largest circle). Clearly mark the point on the ground beneath the plumb-line: this point lies on the tra
41、ctor clearance circle.5.1.1.4 Measure (3.1) the diameter of the turning circle (see 5.1.1.2) at a minimum of three places spaced approximately equally around the circle as shown in Figure 4. Calculate the average value of the diameter measured and report it as the “minimum turning diameter, right-ha
42、nd, without brakes”.5.1.1.5 Measure and record the radial distance between the point on the tractor clearance circle (see 5.1.1.3) and the circumference of the tractor turning circle (see 5.1.1.2). Add twice this dimension to the minimum turning diameter and report the result as the “minimum clearan
43、ce diameter, right-hand, without brakes”.5.1.2 Alternate GPS method5.1.2.1 Drive the tractor slowly forward while making its sharpest possible right-hand turn, that is, with the steering kept on full right-hand lock, at a speed not exceeding 2 km/h for at least one complete turn, until it is establi
44、shed that the minimum turning circle is being described.5.1.2.2 The diameter of the turning circle shall be calculated as shown in Figure 5 and report it as the “minimum turning diameter, right-hand, without brakes”.5.1.2.3 Measure and record the lateral and longitudinal position from the GPS receiv
45、er (3.3) to the points on the vehicle most likely to produce the largest clearance circle. Calculate as shown in Figure 5 and record the largest clearance circle diameter.5.2 Left-hand turn, without brakesRepeat the procedures described in 5.1 with the tractor driven forward while making its sharpes
46、t possible left-hand turn, that is, with the steering kept on full left-hand lock. Report the results as the “minimum turning diameter, left-hand, without brakes”.6 ISO 2015 All rights reservedBS ISO 789-3:2015ISO 789-3:2015(E)5.3 Right-hand turn, with brakesWhere applicable, repeat the procedure de
47、scribed in 5.1 with the inside non-steered wheel brake applied with a pedal effort sufficient to lock the wheel, subject to a maximum of 60 daN.Report the results as the “minimum turning/clearance diameter, right-hand, with brakes”.5.4 Left-hand turn, with brakesWhere applicable, repeat the procedur
48、e described in 5.3 with the tractor making its sharpest possible left-hand turn, that is, with the steering kept on full left-hand lock.Report the results as the “minimum turning/clearance diameter, left-hand, with brakes”.Figure 4 Calculation of the diameters from measurements between three approxi
49、mately equally spaced circumference pointsDABCAB AC BC ABC=+()+()2222 22 22 444 ISO 2015 All rights reserved 7BS ISO 789-3:2015ISO 789-3:2015(E)Figure 5 Geometric for calculation of the turning diameterCEFLF=+(cos )( sin)222=+tan(cos )(sin )1 2EFLFDDLCDLCtGPSGPS= + +2222222 222( ) () cos( )pi8 ISO 2015 All rights reservedBS ISO 789-3:2015ISO 789-3:2015(E)DDLLMNDLLMNcGPSGPS= + +2222222 22 22 22( )() () () cos(pi+tan()1NLMSymbol ExplanationDtminimum turning di
