Promising mobile vehicles with ultra-low pressure tires for agricultural production

BACKGROUND: The article presents the results of experimental studies to assess the vibration load of the dynamic system of the mobile vehicle MEV-600 equipped by an ultra-low pressure tires 1020x420-18 model Bel-79 and an independent suspension during driving on artificial irregularities. As a result of the tests carried out, dependences were obtained to assess the impact on the vibration load of the mobile vehicle of the high-speed mode, tire air pressure and the tank filling degree by process fluid. The obtained dependences show us that their characteristics have a linear dependence in the pre-resonant and post-resonant zones, and a progressive–regressive dependence in the resonant zone. It has been experimentally established that the MES-600 dynamic system has high vibration-proof properties, therefore, an introduction of local springing of operator’s seat is not advisable in the layout scheme, where operator’s cab is located behind the front wheel axle, since the level of vibrations on operator’s seat does not exceed the normative indicators.

AIMS: experimental evaluation of the influence of the parameters of the dynamic system of a mobile power vehicle equipped by an ultra-low pressure tires on its vibration-proof properties and dynamic loading of the structure.

METHODS: The methods of laboratory and field studies on the passage through artificial irregularities are given. The determination of the maximum vertical vibration acceleration on the operator’s seat was carried out using a semi-rigid installation disc, in accordance with the requirements of GOST ISO 10326-1.

RESULTS: The dependences of the tire air pressure and the speed of the MES-600 on the level of vibrations of unsprung and sprung masses when driving over artificial irregularities are obtained. Analysis of these dependencies shows that the characteristics have a pronounced stepwise appearance with three characteristic sections: I – before resonant; II – resonant and III – beyond resonant. In the pre-resonant and over-resonant zones, there is a proportional increase in accelerations on the wheel axis and on the frame above the front axle. In the resonant zone, the characteristics have a progressive-regressive dependence.

CONCLUSIONS: Tests on artificial irregularities have shown that the MES-600 dynamic system has high vibration-proof properties: with full refueling and with 50% refueling of the tank, the level of vibrations over the front axle decreased by five times, and when driving in the current state decreased by 3.7 times, relative to vibrations on the wheel axis; on operator’s seat at various when refueling the tank, the level of fluctuations decreased on average from 3.1 to 4.5 times, relative to fluctuations over the front axle. At high-speed driving modes from 3 m/s to 12 m/s, the level of vibrations on operator’s seat is in the range from 0.063 g to 0.037 g and does not exceed the standard indicators.