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Research of noise in tractor K700 cabin

Pobedin A. V., Dolotov A. A., Iskaliev A. I., Potapov P. V.

Journal of KONES

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2015

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Vol. 22, No. 1

261--264

EN

This paper briefly describes method of noise-measuring tractor’s K700 cabin, obtained noise spectres were analysed and recommendations based on these results for noise decreasing in cabin K700 are proposed. Air noise penetrates into the tractor’s K700 cabin through panels, enclosures, apertures, chinks etc. Structural noise in the cabin is caused by vibrations transfer from sources along tractor frame through vibration isolators to cabin walls and carcass. At that, the main noise sources are engine case, air system, exhaust system, engine cooling system fan and also transmission case located under cabin floor. Every panel in the cabin has own intensity of sound waves radiation and thus contributes to forming of the sound field on the operator workspace. Therefore, it is important to know the sound pressure level near every panel into the cabin. It was state that at low frequencies, noise from left windshield prevails. In addition, in high frequencies bands the highest sound pressure issues from partition between engine area and cabin. Noise spectres have sound pressure peaks in bands with centre frequencies. Total noise level perceived by operator in tractor cabin is less during tractor motion on dirt road without aggregate than during its work with seeding machine on field prepared for winter grasp. At that, partition between engine area and cabin contributes greatly. Thus, for integrated noisiness, reducing in the tractor cabin sound isolation of partition between engine area and cabin should be increased and also sound isolation of windshields located closely to exhaust pipe has to be improved. To decrease low-frequency noise optimization of tractor cabin vibration isolation system need to be performed.

2

Method of evaluation of the probabilistic dispersion of traction and transport vehicles estimated noisiness

Dolotov A. A., Pobedin A. V., Iskaliev A. I., Potapov P. V., Bezverhov V. A.

Journal of KONES

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2015

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Vol. 22, No. 1

91--94

EN

This paper describes questions, which are connected with possibility of obtaining the dispersion of traction and transport vehicles (TTV) noisiness computation on the stage of its development. Experimental data shows that noise around TTV and at operator workplace has wide dispersion of values for even one model produced by one factory at the same time. It concerns practically every type of TTV – new and with some operating time, at mass, individual and serial producing, and at similar operation conditions. Mathematical functions for determination of dispersion mentioned above in dependence on confidence interval of various sources noisiness were obtained. The general method for assessment of probabilistic dispersion of estimated noisiness results is presented. This general method for probabilistic dispersion of computational evaluation of TTV noisiness consists of next stages: assessment of dispersion (confident interval) of acoustic power of each separate noise source; determination of computational function (choice or compiling formulas for computation); determination of dispersion (confident interval) for sound absorption coefficients and other independent variables; determination of partial derivatives for computational function on each independent variable; obtaining of functional dependence of result dispersion of input factors (arguments); calculating of numerical assessment value of TTV noisiness determination result.

3

Decreasing of vibration load level on tractor operator’s working place by means of using of vibrations dynamic dumpers in cabin suspension

Shekhovtsov K. V., Sokolov-Dobrev N. S., Pobedin A. V., Liashenko M. V., Shekhovtsov V. V., Potapov P. V.

Journal of KONES

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2015

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Vol. 22, No. 1

276--284

EN

This paper is devoted to describing of method of decreasing of vibration load level on tractor operator’s working place by means of using of vibrations dynamic dampers in cabin suspension (on other words – dynamic absorbers of dynamic vibroisolators). Standard cabin vibroisolators of tractors DT and VT series include monolith rubber block and have limited capabilities to change its elastic parameters adaptively during impact of vertical and lateral vibration loads with various frequencies. Elastic-damping properties of these vibroisolators does not allow to provide comfortable conditions for operator work because their abilities of vibration damping are not enough especially at low-frequency vibrations. Dynamic vibration dampers installed in cabin suspension were proposed by authors for decreasing of vibration load level on operator workplace. These dampers include additional masses connected to main mass due to elastic-damping elements. Several variants of dynamic vibroisolators schemes were proposed by authors. These schemes differ in quantity of additional masses (one, two or three) and type of connection between additional masses and main mass due elastic-damping elements (parallel or in series). Three-dimensional model of caterpillar chassis, suspension, engine, cabin and operator’s seat of tractor was created in software “Universal mechanism” for performing of computational research. On this model, researches of vibration of sprung mass were made for tractor motion with and without hook load at 3rd and 7th gears on smooth surface and on testing areas with single, periodic and random bumps. Research results indicate undoubtedly best vibroprotective properties of cabin’s suspensions with dynamic vibroisolators.