The main drawbacks of cultivators intended for the tillage of stony soils are low reliability of the working bodies, high draught resistance and inability to maintain the required depth of tillage. Hence, the scientists in the Gorsky State Agrarian University conducted a range of studies and trials that allowed them to improve the design. The aim of the present study was to develop a new design of the closed-circuit elastic suspension for the working bodies of a cultivator that is intended for the performance on stony soils and provides high reliability, low draught resistance of the working bodies (in comparison with the existing models), and the required depth of tillage. The tests of the proposed design were performed in the laboratory conditions on a specially designed and constructed stand equipped with tensometric devices. Horizontal and vertical stiffness of the suspension and its frequency was studied. The field trials were performed by a specially constructed machine that was mounted on a tractor. The machine was equipped with tensometric gauges that were reading the sensors with the frequency of 1000 times per second. All the primary data were processed by the respective methods of mathematical statistics. The authors identified the effective model of the closed-circuit elastic suspension for the central working body with the radius of bows R1=125mm, R2=135mm, horizontal stiffness Сhor=25.6 N/mm and natural vibration frequency ν ϵ [10.2…16.2] Hz. A closed-circuit bow type suspension with the stiffness Сhor=18.34 N/mm and natural vibration frequency ν ϵ [8.5…8.7] were most suitable for the side working bodies of a cultivator. It was established that in comparison with the traditional mounting of working bodies, the designed elastic suspension of the working bodies provided the reduction of the draught resistance by 3.7…15%, high reliability and uniform required depth of tillage.

The article is devoted to the search for a mathematical model convenient for practical calculations to determine the critical value of the angle of gradient for the tractor-mounted heavy tilther. It shows the existing mathematical model, which is then refined based on the stiffness of the elastic tractor wheels and their vertical reactions offset. Three methods of solving the resulting equations are analyzed, upon which the optimal one is chosen. As a result, a simple and convenient in practice mathematical model to determine the critical value of the angle of gradient for the tractor-mounted implement is obtained. The analysis of the calculation results showed that depending on the operating conditions and the weight of the tractor counterweight, the differences between the results calculated using the traditional and refined models can reach more than 4 degrees, which is very important to ensure the hill climbing safety.

The article deals with a design of the adjustable lightweight safety device made from composite materials and used for reversible plows. Initially, a design scheme was developed. It was theoretically and experimentally investigated. Research was conducted by the Department of Tractors and Agricultural Machines of the Gorsky State Agrarian University. As a result, software was developed. It is used to determine rational values of the main parameters of the safety lock. The following values of the parameters were obtained: the diameter of fiberglass rods dr = 16 mm; the rod length lr = 0.85 m; the number of rods nr = 16 (8 in each spring); the height of the center of the stop e = 0.15 m; the radius of the crank rr = 0.12 m; the rod length lr = 0.25 m; the initial value of the angle of crank rotation acro = 30 … 700. During the laboratory experimental studies, using the strain gauging method, we studied a change in the traction resistance of a section when it is deepened, and reliability of obstacles of various heights. The traction resistance was 7800 … 11600N, which is sufficient to ensure reliable operation of the plow section in the North Caucasus region. In all experiments, a decrease in the traction resistance was observed when the section returned after deepening to its original position, which was caused by the gravity section and hysteresis losses in the composite rods. Field tests of the upgraded model of the reversible plow PON-3 confirmed high efficiency of the safety lock design.

The article provides analytical dependences for calculating such important parameters of the cutter for soil cultivation as the number of revolutions of the shaft with the knives fixed on it, the indicator of the kinematic regime, feed to the knife, as well as the power consumed by the cutter. Taking into account the results of research by other authors, numerical calculations were carried out. The following are the results of experimental studies of the process of milling the soil, carried out using a prototype machine. The torque on the drive shaft of the machine was determined using the strain gauge method. To determine the rotational speed of the cutter shaft, optical sensors were used, the translational speed of the machine was determined based on the processing of signals from a speed meter driven by the support wheel of the machine. As a result, it was found that the milling cutter with the values of the parameters determined theoretically provides high quality soil cultivation. The calculated values of the power consumed by the cutter are in good agreement with the experimental results.

The article is devoted to the improvement of the tiller designed to operate on rocky soils. The elements of the interaction theory between the tiller work tools and the rocks in the soil are presented. Two cases of the machine blade hitting a rock were analyzed. The improved machine design containing safety devices and a digital alarm system that reports the operator on the safety device response is proposed. Safety devices are installed on each machine section, which reduces the area of untilled soil during their response. A contactless sensor is installed above each section, the signal from which is analyzed by a measuring device according to a special algorithm. Rational values for the main parameters of the tiller section fuses are determined and the time of the section blade hit a rock is studied. The improved tiller sample testing of 2020 and 2021 on rocky soils in the mountainous terrain proved the efficiency of the proposed design.