Operational failure of tractor gears

Vinokurov, G. G.; Yakovleva, S. P.; Vasileva, Marina; Makharova, S.N.

doi:10.3103/s1068798x12030239

Cited by 2 publications

(5 citation statements)

References 2 publications

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“…The original gear micro hardness is confirming the recommended values ISO 6336-5 [4] and reference [5], as shown in table (1) and figure (6).…”

Section: Discussion Of Resultssupporting

confidence: 76%

“…ISSN: 2319-1058 Gear (1) had some broken teeth and cracks at the keyway, as shown in figure (4) but not complete separation as the original gear, figure (2). Also, gear (2) had some broken teeth and cracks at the keyway, as shown in figure (5). Both manufactured gears had a severe pitting through the most of gears' teeth, as shown in figures (3, 4 and 5).…”

Section: Observations and Reviewmentioning

confidence: 92%

“…Vinokurov et al [5] concluded that the failure of gears was occurred due to the insufficient hardness of the case because it was varying between 53 to 58 HRC and this value is not satisfying the standard GOST 21354-87 established the hardness of surface hardened teeth within the range of 56-63 HRC.…”

Section: Literature Surveymentioning

confidence: 99%

“…Usually those gears have about 20 years' life but the manufactured set was failed within 3 weeks and that not logically so the failure reasons must be investigated to overcome in the future. Visual inspection had carried out and set of photos were taken for recording the conditions of the gears as shown in figures (1,2,3,4,5) for the original and manufactured gears. Micro hardness survey was done and microstructure investigation was applied.…”

Section: Introductionmentioning

confidence: 99%

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Failure Analysis for Angle Head Spiral Gears

2017

IJIET

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In this paper, a failure analysis for angle head spiral gears of CNC milling machines is investigated for discovering the failure reasons and so overcoming them in the future. Two spiral mating gears' set is of identical dimensions and its role is to convert the vertical motion to horizontal motion for a certain machining operations is studied in this research work. The gears are manufactured from carburized steel (18CrNiMo7-6), DIN standard No.1.6587. The gear module is 4 mm and number of teeth is 22 teeth. The gears have been failed after 2 weeks of operation. A visual investigation has been carried out and a set of photos were taken. The visual investigation showed that the gears have undergone some broken teeth. The operating conditions have been revised during consecutive intervals of operation. The design data has been reviewed according to standard gear design recommendations followed by a check for the manufactured gear data according to that design data. Material analysis and micro hardness measurements followed by a microstructure have been also investigated. Heat treatment faults were found. The micro hardness survey through the teeth tips and roots were not correct because there was a decarburization at the manufactured gear up to 1 mm case depth and the carburizing depth at the teeth tip 2-2.2 mm is not suitable and more than the standards recommendations to the gears of module 4 mm. The micro hardness measurements and micro structure revealed that the case hardness at gear tips was less than at its roots. This refers to an excessive retained austenite due to the slow rate of cooling in the quenching operation which did not avoid the CC curve nose and the gear temperature was less than 700 Co before quenching. In addition, the thick layer of the carburized case may lead to more probable to retained austenite formation. The thick carburized layer at teeth tip leads to brittle teeth at their tip, which leads to their failure due to sudden or impact loads. Therefore, it is recommended to select the carburizing parameters matching with standards recommendations of the carburizing layer with maintaining its thickness difference at both the teeth tips and roots.

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“…The original gear micro hardness is confirming the recommended values ISO 6336-5 [4] and reference [5], as shown in table (1) and figure (6).…”

Section: Discussion Of Resultssupporting

confidence: 76%

Section: Observations and Reviewmentioning

confidence: 92%

Section: Literature Surveymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Failure Analysis for Angle Head Spiral Gears

2017

IJIET

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“…The material analysis confirmed suitable material as required, microhardness survey of the pinion had revealed that a carburizing case depth at the teeth was not confirming the recommended values of references [17,18] because the depth equal 2.3 mm and it is much greater than the recommended suitable to the case data which causing the carburizing case is full hardened portion at the tip of the teeth. So, this portion miss its toughness and could not resist impact load.…”

Section: The Material Microhardness and Microstructurementioning

confidence: 98%

Failure analysis for high stress gear

2017

IJLTET

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INTRODUCTIONGear failure is one of the most serious problems causing a headache to gears designers, manufacturers and users. The industrial processes do not need an unplanned shut down due to any reasons because it cost a lot of money and waste of time and effort. Gear failure have many reasons to occur; it may happen due to a lot of error sources in gear process production such as: design, manufacturing, heat treatment, maintenance or random so, the problem of gear failure must be analyzed, investigated, and clearly solved for avoiding its bad effects in the operation. The present case investigates a pinion gear failure in sugar industry which was subjected to a high stress due to, high power drive motor 315 kw, single stage reduction of 16/70, module 5.08 and width 85 mm. the gear box is driving a circulation fan which is critical in the industry process. This circulation fan must work 24 hrs / day. The environmental and operating conditions were reviewed carefully searching for corrosion, erosion or overload causes. The routine maintenance was carried out. Material selection and heat treatment specifications were analyzed and compared to gear standard design recommendations. Visual inspection and a set of photos were taken for documenting the failure case as shown in figures (1, 2, 3). Micro hardness survey was carried out to the teeth and the area between teeth at the root sections. Also the gear microstructure was investigated looking for the microstructure and compare it with the target microstructure of the standards. The contact stress and bending stress on the teeth are calculated regarding the operating conditions. The gear design criteria were reviewed concerning the design standards procedures and recommendations. The results of the above investigations were discussed concerning the design and standards requirements. Also a comparison with other works was done. Finally conclusion and recommendations were drawn.

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Operational failure of tractor gears

Cited by 2 publications

References 2 publications

Failure Analysis for Angle Head Spiral Gears

Failure Analysis for Angle Head Spiral Gears

Failure analysis for high stress gear

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