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GB/T 24648.1-2009 English PDF

GB/T 24648.1-2009 (GB/T24648.1-2009, GBT 24648.1-2009, GBT24648.1-2009)
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BASIC DATA
Standard ID GB/T 24648.1-2009 (GB/T24648.1-2009)
Description (Translated English) Assessment of tractor reliability
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard T60
Classification of International Standard 65.060.10
Word Count Estimation 20,274
Date of Issue 2009-11-15
Date of Implementation 2010-05-01
Quoted Standard GB/T 3871.3; GB/T 3871.4; GB/T 3871.6; GB/T 3871.12; GB/T 6229; GB/T 24648.2-2009
Drafting Organization National Quality Supervision and Inspection Center tractors
Administrative Organization National Standardization Technical Committee tractor
Regulation (derived from) National Standard Approval Announcement 2009 No.13 (Total No.153)
Summary This standard specifies the terms and definitions tractor reliability assessment, fault classification and judgment rule, assessment index system, assessment methods and the use of tractors reliability test methods. This section applies to the tractor has been finalized for the evaluation of the reliability, the reliability of the prototype trial assessment can also be implemented by reference.

GB/T 24648.1-2009 NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 65.060.10 T 60 Assessment of tractor reliability ISSUED ON: NOVEMBER 15, 2009 IMPLEMENTED ON: MAY 01, 2010 Issued by: General Administration of Quality Supervision, Inspection and Quarantine; Standardization Administration of the People's Republic of China. Table of Contents Foreword ... 3  1 Scope ... 4  2 Normative references ... 4  3 Terms and definitions ... 4  4 Fault classification and judgement rules ... 6  5 Evaluation indicator system ... 8  6 Evaluation methods ... 11  7 Use test methods ... 12  Annex A (Informative) Tractor test summary ... 18  Annex B (informative) Examples of tractor faults ... 26  Assessment of tractor reliability 1 Scope This Part of GB/T 24648 specifies terms and definitions, fault classification and judgment rules, evaluation indicator system, evaluation method for assessment of tractor reliability as well as test methods for tractor reliability during use. This Part is applicable to reliability assessment and evaluation of shaped tractor. Reliability assessment of prototype tractor may refer to this Part. 2 Normative references The provisions in following documents become the provisions of this Part of GB/T 24648 through reference in this Part. For dated references, the subsequent amendments (excluding corrigendum) or revisions do not apply to this Part, however, parties who reach an agreement based on this Part are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies. GB/T 3871.3, Agricultural tractors - Test procedures - Part 3: Power tests for power take-off (GB/T 3871.3-2006, ISO 789-1:1990, MOD) GB/T 3871.4, Agricultural tractors - Test procedures - Part 4: Rear three-point linkage lifting capacity (GB/T 3871.4-2006, ISO 789-2:1993, MOD) GB/T 3871.6, Agricultural tractors - Test procedures – Part 6: Determination of braking performance (GB/T 3871.6-2006, ISO 5697: 1982, Agricultural and forestry vehicles - Determination of Braking Performance, IDT) GB/T 3871.12, Agricultural tractors - Test procedures - Part 12: Working tests GB/T 6229, Test methods for walking tractors GB/T 24648.2-2009, Reliability assessment of engineering and agricultural machine - Evaluation parameter system and failure classification code 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 operating time The time for a product to complete various defined functions. For tractor, operating time includes tractor load operation time, turning time at turn-row and conversion time for tractor’s null operation (5h null operation time is converted to 1h working time), but excluding tractor running-in time, performance test time and engine idle time. 3.2 fault correction time The time required from fault is found to product function is recovered, that is, the sum of fault diagnosis time, repair time and commissioning time, but excluding time delayed by human or natural factors. 3.3 maintenance time The operating time required to complete maintenance specified in user manual. It includes shift maintenance and time spent on maintenance at all levels, but excluding time delayed by human or natural factors. 3.4 fault All phenomena that a product or its component cannot perform its specified functions or performance indicators are deteriorated beyond specified range (see 2.2 in GB/T 24648.2-2009). For example, parts damage, wear overrun, weld cracking, paint peeling, loose fasteners, sign off and difficulty in starting, power reduction, fuel consumption increase, slow rise and other phenomena that exceed specified values. 3.5 inherent weakness fault Under specified conditions of use, the fault that is caused by defect inherent in product itself. For example, excessive deformation, fracture, early wear and fatigue of parts, abnormal corrosion and aging, loosening or failure of fasteners, performance degradation, and "three leaks" (see 2.3 in GB/T 24648.2-2009). 3.6 secondary fault The fault of other parts of product that is directly or indirectly caused by fault of some part of product, or the derived fault caused by inherent weakness fault. For example, when engine is broken due to broken connecting rod bolts and damages of a series of parts such as connecting rods, bushings, pistons and cylinders, broken connecting rod bolts shall be inherent weakness fault, and damages of a series of parts shall be secondary fault (see 2.4 in GB/T 24648.2- 2009). See formula (2) for mean interval time between faults. Where, MTBF - Mean interval time between faults of tractor, in hours (h); tci - Timing end test time of the ith tractor to be tested, in hours (h); for tractor to be investigated, it is accumulated operating time, in hours (h); ra - Total number of faults (except minor faults) of tractors to be tested or investigated during use or test period (including during run-in and performance test). If all tested tractors have no faults (except minor faults), it is specified to use to represent. 5.4 Mean interval time between downtime faults See formula (3) for mean interval time between downtime faults. Where, DTMTBF - Mean interval time between downtime faults of tractor, in hours (h); rd - Total number of downtime faults (i.e., fatal faults and severe faults) of tractors to be tested or investigated during use or test period (including during run-in and performance test). If all tested tractors have no faults (except minor faults), it is specified to use to represent. 5.5 Trouble-free comprehensive score Within specified test time, if one of tractors to be tested has fatal fault, this type of tractor shall fail in trouble-free comprehensive score. Its Q value shall not be calculated. For tractor to be tested that has no fatal fault, its trouble-free comprehensive score is calculated according to formula (4): or total cost of troubleshooting of this type of tractor (including replacement and repair costs) during test period specified in 7.3.3.2, in RMB; Ct - Unit price of this type of tractor, in RMB. 6 Evaluation methods 6.1 Data sources Sources that are used to evaluate tractor reliability may come from the following three aspects. 6.1.1 Use test According provisions of Clause 7, perform reliability test, combing with production use. 6.1.2 Laboratory or test site reliability test According to method specified in relevant standard, perform reliability test in laboratory or on test site where conditions are controllable. However, equivalent relationship between such test time and actual use time of user shall be known in advance. 6.1.3 User survey Conduct sample surveys or full follow-up surveys among users to obtain reliability data for actual use of tractor. 6.2 Fault determination For all faults of tractor, according to provisions of Clause 4, determine the nature of each fault and its category one by one, which are used as basis to calculate relevant indicators. 6.3 Marking methods for indicator Marking format for tractor’s reliability indicators is specified as follows: Indicator code = indicator value (data source) For example: reliability indicators for tractor of which ××× type engine calibration power is less than 18kW are as follows: MTTFF=150h (3×500h use test) MTBF=250h (3×500h use test) load specified in user manual. Lifting time is the time used when lower suspension point rises from the lowest point to the highest point when throttle is fully open. 7.3.2.3 Brake test According to provisions of GB/T 3871.6, measure maximum average deceleration speed of cold braking. 7.3.3 Put test prototype into normal use under actual conditions for use. It shall use and perform maintenance strictly according to provisions in user manual. All kinds of work quality shall meet agronomic requirements. 7.3.3.1 Record test situation of each test prototype in details according to Table A.5. 7.3.3.2 Total working time of test prototype is 1500h. It is 2×750h for tractor of which engine calibration power is greater than 18kW, 3×500h for rest tractors. 7.3.3.3 Work items for each test prototype: field work item (ploughing, hoeing, sowing, collecting) time of wheel tractor and walking tractor is not less than 70% of total operating time; transportation time is not more than 30%; fixed work is not allowed. For crawler tractor, all are field work, and fixed work is not allowed. For forestry skidding tractor, all are skidding work. Work items and time proportion for tractors of other special uses are drafted and determined by referring to this Part. 7.3.3.4 During test process, it shall measure at any time hourly fuel consumption required to complete various works, so as to determine and adjust load degree of each test prototype. Average load factors for field work of wheel and walking tractors shall not be lower than 55% and 50%, respectively; transportation work is rated load mass. Average load factors for field work of crawler tractor shall not be less than 60%. Carrying capacity of forestry skidding tractor shall not be less than 80% of rated carrying capacity. 7.3.3.5 For all faults happened during use test (including run-in and performance tests), it shall record occurrence time, situation, cause analysis, repair work time in details. When necessary, it shall take photos and conduct physical and chemical analysis. For all faults, it shall, according to relevant provisions of Clause 4, determine their categories to which they belong and record them in Table A.6 and Table A.7. 7.3.3.6 In test, general fault and severe fault shall be excluded before test is continued. In the event of any major damage caused by non-essential causes, organization in charge of test may negotiate with entrusting party before it selects another prototype for testing. If test is a sampling test, it must be reported to entrusting authority for approval before standby prototype can be Where, Qso - Total workload to complete a work, in hectares (ha) or tons kilometers (t·km); Qs - Shift workload to complete a work, in hectares (ha) or tons kilometers (t·km). d) Average productivity Respectively collect according to work category. Average productivity is calculated according to formula (10). Where, qsp - Average productivity of tractor to complete a work, in hectares per hour (ha/h) or tons kilometers per hour [(t·km)/h]; ts - Shift operating time to complete a work [see formula (11)], in hours (h). e) Average hourly fuel consumption See formula (12) for average hourly fuel consumption. Where, Gtp - Average hourly fuel consumption of tractor to complete a work, in kilograms per hour (kg/h); Gs - Total fuel consumption of tractor to complete a work, in kilograms (kg); Gfk - Idling hourly fuel consumption of tractor engine, in kilograms per hour (kg/h). f) Average unit workload fuel consumption See formula (13) for average unit workload fuel consumption. Table A.2 -- PTO shaft (engine bench) test results Tractor model _________ Manufacturer ______ Engine model ___ Test site _________ Inspection basis _______________ Test date: before test _________ after test _______ Average atmospheric conditions during test: Before use test: temperature _____°C Air pressure _____kPa Relative humidity _____% After use test: temperature _______°C Air pressure ______kPa Relative humidity ____% Highest temperature during test: Before use test: cooling water _____°C Lubricating oil _____°C Fuel ____°C Intake ___°C After use test: cooling water ______°C Lubricating oil ___°C Fuel _____°C Intake _____°C Number of test prototype 1 2 3 Performance parameter Pd/kW ne/(r/min) Gt/(kg/h) gd/[g/(k W·h)] Pd/kW ne/(r/min) Gt/(kg/h) gd/[g/(k W·h)] Pd/kW ne/(r/min) Gt/(kg/h) gd/[g/(k W·h)] Be for e t es 1) Ma xim um po we r o ca libr ati on sp ee 2) 85 of ite 1) tor qu 3) 75 of ite 2) tor qu 4) 50 of ite 2) tor qu 5) 25 of ite 2) tor qu 6) No loa d - - Av era ge - - - Table A.5 – Use test shifts of tractor reliability Tractor model ______________ Prototype No. __________ Test date ________________ Work name _________ Soil type and vegetation (or road) conditions ________________ Work situation: working depth ______cm working width ____cm or loading mass _______t Workload of this shift: working area __________ha Transportation load _________ t·km Fuel consumption of this shift: fuel ____kg Engine oil ___kg Chassis lubricant ________kg Work content Start time End time Duration / h min Work gear Downtime / min Null operating time / min Idling time / min Total Maintenance time of this shift __ h __min Fault repair time ___ h ___min Tractor working time __h ___min Note: Recorder: Reviewer: Participant: Table A.6 -- Registration of use test faults of tractor reliability Tractor model ________ Manufacturer ________ Prototype No. _____ Test date _______ Fault appearance date _______________ Work name _________________________ Accumulated operating time of tractor _________________ h List of parts damaged in this fault: Name No. of piece Number of pieces Accumulated operating time of each part / h Exit-factory unit price of this part / RMB Description of fault phenomenon and its influence degree (with photo) Fault cause and its physical and chemical test results: Troubleshooting method: Fault category _______________ Fault repair time _________h Repair cost______ RMB Table A.9 – Comprehensive collection of user test of tractor reliability Tractor model __________ Manufacturer ___________ Test start and end date ______ Test prototype No. 1 2 3 Accumulated operating time / h Accumulated idling time / h Accumulated maintenance time / h Accumulated repair time / h Accumulated fuel consumption / kg Fuel Lubricating oil Engine Chassis Accumulated workload Field / ha Transport / (t·km) Average hourly fuel consumption / (kg / h) Field Transport Average unit workload fuel consumption Field / (kg/ha) Transport / [kg/(t·km)] Operating-time proportion of each gear / % Gear Gear Gear Gear Gear Average load coefficient of field work/% Field work time as a percentage of total time /% Recorder: Reviewer: Participant: Table A.10 -- Evaluation results of tractor reliability Tractor model ____ Manufacturer _______ Test start and end date _______ Accumulated number of faults (times): No. of test prototype 1 2 3 Total Fatal fault Severe fault General fault Minor fault Total Reliability indicators MTTFF= h ( h use test) MTBF= h ( h use test) DTMTBF= h ( h use test) Q= h ( h use test) PWC= h ( h use test) Recorder: Reviewer: Participant: Annex B (informative) Examples of tractor faults B.1 General parts are in accordance with provisions of Table B.1. Table B.1 No. Name Fault mode Situation description Category 1 Body, rack, walking equipment Breaking, disengaging I 2 Internal parts of body Damaged or invalid II 3 Important parts and components outside body Damaged or invalid II 4 General parts outside body Damaged or invalid III 5 Important fasteners outside body Multiple damage Fastener bolt strength of 8.8 or more, nut of 8 or more, causing connection failure II 6 Important fasteners outside body Individually damaged or loosened multiple times No connection failure III 7 General fasteners outside body Damaged or detached No connection failure IV 8 Part joint surface Serious “three leaks” Exclude by disassembling and replacement II 9 Part joint surface “Three leaks” Exclude by not disassembling and replacement III 10 Part joint surface Leakage Wet IV 11 Warning sign or seal Falling off III 12 Non-warning sign Falling off IV 13 Surface paint wax and electroplated coating Large pieces of flakes III 14 Surface paint wax and electroplated coating Falling off IV 15 Non-essential plastic parts Cracks IV 16 Butter mouth Damaged or detached IV ...