PRESSURE ON THE SOIL OF HOPPER LOADERS IN WORKING CYCLES MAINTENANCE OF COMBINE HARVESTERS

The problem of soil compaction by heavy transport equipment used to transport grain from combines, the solution of which is associated with the use of bunker-loaders (BL), is currently becoming more acute. However, the lack of indicators of the pressure on the soil of their running systems (when moving across fields) and the methodology for assessing the impact of BL on the soil with different body loads of grain, prevent comparative assessments of BL and an objective choice by agricultural producers of samples with the lowest pressure on the soil. The distances of passes across the field in the working cycles of BL for the variants of the number of combines serviced are modeled using original formulas as a result of research. It was found that the total length of the BL run across the field Ltotal in the working cycle is directly proportional to the length of the run Lg of the harvested field and the number of combines serviced. It consists of separate sections-passages characterized by successively increasing soil compaction, the value of which in turn depends on the mass of the loaded grain and the number of support wheels of the BP. The proposed expression for calculating the vertical load on the wheels of the bunker-loader, taking into account the change in the weight of the grain in the body, provides the ability to calculate the maximum pressure on the sections of the BP movement across the field when servicing combines for subsequent comparison with the regulated permissible pressure. It was found that with each loading of grain from the combine bunker, the maximum pressure of the wheels on the soil increases by 104 and 80 kPa for BP with four support wheels and by 38-50 kPa - with eight support wheels, with an increase in pressure to 382-394 kPa and with an excess of the permissible value by 1.8-1.9 times. When working with grain reception in a heavy-duty BP from three bunkers of TORUM combines instead of the possible four, the maximum pressure on the soil is reduced by 9.9% (from 382 to 344 kPa), and when receiving grain from two bunkers - by 20.7% (from 382 to 302 kPa).