DESIGN OF A ROLL CRUSHER FOR SUNFLOWER STEMS AND SUBSTANTIATION OF THE RATIONAL MODES OF ITS OPERATION

V i k t o r S h e i c h e n k o Corresponding author Doctor of Technical Sciences, Professor Department of Technology and Means of Mechanization of Agricultural Production* Е-mail: vsheychenko@ukr.net V o l o d y m y r V o l s k y i PhD, Senior Researcher** R o s t y s l a v K o t s i u b a n s k y i Postgraduate Students Testing Center** V i k t o r D n e s PhD Department of Modeling Technology Systems and Technical Services of Market Agricultural Production** M i s h a S h e v c h u k Doctor of Philosophy Department of Agricultural Engineering Uman National University of Horticulture Institutska str., 1, Uman, Ukraine, 20305 O l e k s a n d r a B i l o v o d PhD, Associate Professor Department of Industrial Engineering* O l g a D r o z h c h a n a Department of Safety of Life* *Poltava State Agrarian University Skovorody str., 1/3, Poltava, Ukraine, 36003 **National Scientific Center «Institute of Agricultural Engineering and Electrification» Vokzalna str., 11, Hlevakha vill., Ukraine, 08631 This paper reports a study of the technological process of grinding plant residues of sunflower and the causal relationships of factors that form the system of quality indicators. The necessary prerequisites for determining rational modes and parameters of the roll crusher have been devised. A prototype of the roll crusher was designed and fabricated, in which the cutting knives are arranged along the entire width of the grip in a staggered manner, with the possibility to change the angle of inclination to the axis of drum rotation in the range of 5...20°. It was established that in the case of the right-side arrangement of the cutting edge of knives, the highest total level of the percentage of crushed stems in the range of 101–150 mm with an additional load weighing 800 kg exceeded by 1.58 times the corresponding indicators of the roll with an additional load of 600 kg. The largest overall value of the percentage of crushed stems in the range of 0–200 mm when additionally loading the roll with 800 kg was 1.13 times higher than the corresponding indicators of the roll with an additional load of 600 kg. In the range of 0–200 mm, with an additional load on the roll of 600 kg, at the leftside arrangement of the cutting edge of the knives of the roll, higher total percentage of crushed stems was observed compared to the right-side arrangement. At a speed of 7.45 km/h, 13.6 km/h, the cumulative value of the percentage of crushed stems exceeded the corresponding indicators at the right-side arrangement of knives by 1.09 times, at the speed of 18.6 km/h – by 1.04 times, at the speed of 22 km/h – by 1.04 times, respectively. It has been noted that at the left-side arrangement of the cutting edge of the knives of the roll, the percentage of crushed stems in the range of 51–100 mm, with an additional load of 600 kg, exceeded the corresponding indicators with an additional load of 800 kg. At the speed of 10.08 km/h, it was exceeded by 1.9 times; at the speed of 13.6 km/h – by 1.44 times; at the speed of 18.6 km/h – by 1.96 times; at the speed of 22 km/h – by 1.99 times, respectively


Introduction
Technological operations of grinding residues of corn, sunflower, rapeseed, green manure, and a series of other crops are carried out by special machines. The roll crusher in combination with a disc harrow is an extremely effective tool on such an agricultural background. Its action contri-butes to the grinding, partial wrapping of plant residues, as well as the formation of a well-mulched upper layer of soil. This soil layer is characterized by an agronomically valuable structure. Uniform mixing of plant residues with the soil is also advisable in terms of their rapid decomposition, the formation of favorable conditions for sowing, and preventing early clogging.
It should be noted that climate change significantly affects the expansion of forms, types of pests, and plant diseases. When growing corn, farmers are increasingly experiencing a negative impact on the corn by corn butterfly. The use of chemicals does not solve this problem. As practice shows, corn stem choppers are effective in combating this pest.
A series of agrotechnical requirements are put forward to the quality of grinding of residues of coarse-stem crops, the observance of which is possible only if the dependence of quality indicators on technological parameters is taken into consideration. These conditions are basic when designing new machines and tools.
Scientists are constantly searching for new technical and technological solutions and improving the designs of roll crushers. However, the lack of a general methodology for substantiating the rational technological parameters of both combined machines containing disk rotary tools and roll crushers, as well as roll crushers in the form of a mono tool, leads to further serious miscalculations that arise when designing new ones. Blind copying of other people's technological advancements, which is often observed under modern production conditions, leads to the accumulation of problems and the subsequent use of unreasonable solutions.
The quality of operation of roll crushers largely depends on the correct choice of their rational parameters and operating modes, which are fully determined not only by structural features but also by operating conditions. Therefore, investigating the mechanism of influence of the physical and mechanical properties of plant material on the quality of its grinding is a prerequisite for substantiation and development of technological parameters of roll crushers and modes of their operation.

Literature review and problem statement
The dependence of the quality of roll crusher performance on operating conditions is sometimes so noticeable that there is a need to develop a model range of tools for each soil and climatic zone [1]. A wide range of changes in most properties of plant material, even for the same field, is the cause-andeffect factor that predetermines the quality of operation [2].
The use of special machines, which include roll crushers, is advisable only if they are loaded to the full [3]. It should be noted that in addition to sunflower and corn stubble, it is also advisable to carry out operations of grinding and processing green manure, processing of rapeseed stubble, cereals, etc. [4].
On arable lands of many countries, it is most likely that at the same time as the temperature increases in the summer months, we should expect an increase in the deficit of moisture available to plants in the soil [5]. In such climatic changes, the most urgent issues are related to the maximum accumulation of precipitation during the year and the most rational utilization of moisture in the warm period. This can be achieved by wide implementation of such soil cultivation systems that make it impossible to turn the arable layer annually. Such measures improve the preservation and accumulation of mulch soil surfaces, reduce the speed of movement of the ground layer of air, and contribute to better preservation of moisture accumulated during the autumn-winter period [6].
When mechanically processing stubble of coarse-stem crops, the degree of grinding of stems is an important indicator of the quality of the technological operation [7]. For corn, the evaluation criterion is the number of non-damaged parts of stems longer than 5 cm, in which corn butterfly pupae can winter. For other cultures, this indicator is not so important [8].
Under such conditions, we note the absence in the above publications of quantitative assessment of the quality of operations of grinding of coarse-stem crops in the entire range of sizes of plant residues.
Paper [9] reports the results of studying a machine-tractor assembly, which simultaneously performs technological operations of grinding and soil wrapping of plant residues (sunflower stubble). The first operation is carried out using a shredder of plant residues installed in front. The plow installed at the back performs a wrapping operation. It is noted that the number of crushed particles less than 15 cm long increased by 1.5 times, and the number of particles longer than 30 cm decreased by 3 times. When analyzing the entire volume of plant residues in the soil, their non-damaged part did not exceed 1 %. However, the authors ignored the question of determining the impact exerted on the quality of grinding plant residues by the assembly's movement speed.
Study [10] noted that the return and deep burying of agricultural straw in the soil is an effective way to use and process straw resources, reduce pollution, and increase soil fertility. The authors of [10] designed a combined unit for deep harrowing, stubble grinding, turning, and burying crushed straw. Thus, the machine combined the functions of cleaning the stubble and opening the furrow. According to the results of statistical analysis, it was concluded that the speed of rotation of the blade, which destroys the stubble, did not affect the resistance to tillage. However, the depth of soil cutting both by the guide blade and the destruction of the stubble affected the resistance and, therefore, affected the soil cultivation capacity. It is noted that the optimal efforts on soil cultivation and the quality of stubble grinding were, respectively, 21.6 kN and 96.3 % at a rotational speed of 340 rpm. The proposed design of the combined unit is believed to be effective in deep furrowing, soil destruction, stubble breaking, and burying crushed corn straw with good operating quality. However, the authors ignored the issues of influencing the quality indicators of the technological operation of grinding additional vertical weight applied to the chopper.
In order to improve the quality of work and reduce the energy consumption by the machine for grinding straw, a scheme and mechanism of operation of a two-rolling tiller [11] was proposed. According to the results of experimental studies of the proposed design, high quality of work on grinding corn stems was noted. The rate of grinding of stems reached almost 90 %. However, the authors do not give specific values of the degree of grinding of corn stems in the range exceeding 50 mm.
Based on the constructed mathematical model, work [12] analyzed the conditions of interaction of the stem with the cob. Two types of possible options for the arrangement of knives are proposed, which creates the preconditions for designing a new type of narrow-band rotary cultivators and plant residue shredders. However, the authors did not consider an experimental study of the proposed structure.
Mulchers or roll crushers in the solo version, despite their high efficiency in the destruction of stems, on the contrary, do not have the above additional advantages [13]. On the contrary, their unsystematic use can lead to the accumulation of large masses of plant residues on the soil surface, which slows its warming up in spring. Uniform mixing of plant residues with the soil is also advisable in terms of their rapid decomposition, the formation of favorable conditions for sowing, and preventing early clogging [14].
That is why it is necessary to develop roll crushers both in mono-execution and as part of special units. Due to this, it would be possible to subsequently use them for surface tillage with intensive mixing. Among the above-mentioned operations are stubble peeling, field cultivation with a large number of plant coarse residues, pre-sowing tillage, and wrapping of organic fertilizers.

The aim and objectives of the study
The purpose of our study is to design a roll crusher of sunflower stems and to substantiate the rational modes of its operation. This would make it possible to improve the quality of technological operations of crushing sunflower stems by reducing unevenness, reducing energy costs, and intensifying the grinding process.
To accomplish the aim, the following tasks have been set: -to design and fabricate a roll crusher with angles of inclination of cutting knives variable to the axis of rotation; -to investigate the effect of additional vertical weight applied above the center of mass of the roll crusher on the quality indicators of grinding and wrapping of sunflower stems; -to investigate the impact of the arrangement of the cutting edge of a crushing knife of the roll crusher on the quality indicators of the operations of grinding and wrapping sunflower stems; -to investigate the impact of the speed of energy unit on the quality indicators of grinding and wrapping sunflower stems.

The study materials and methods
An experimental sample of the roll crusher of plant residues was investigated atthe research sites of TOV «Krasnyanskye SP «Agromash» (Vinnytsia oblast) and DP DG «Olenivske» NNTs «IMESG» (Kyiv oblast). The test conditions are given in Table 1.
According to the research program, a one-time run through the agro phone was carried out, which was represented by equal areas of the field after harvesting sunflower. During our research, the indicators of crushing and processing plant residues in the soil were determined. The assembly of the roll crusher included the MTS-80 tractor (manufactured at the Minsk Tractor Plant, Republic of Belarus).
In the field, the speed of movement of the energy unit was determined as follows. The plots of the field were in advance divided into sections of length l (l = 100-150 m). The time it took for the unit to travel the plot was determined by a stopwatch. The data acquired were entered in the table. Speed was determined from the following dependence: where t is the time of operation execution at this length of the plot, s. We collected samples of crushed plant mass at different sites of the field both in the width of grip by working bodies of the roll and in the length of the run. At the sites determined in this way, a wooden control frame measuring 1×1 m was placed. Plant residues located both on the soil surface and at the entire depth of cultivation were collected from the frame area in specially prepared and signed packages. Sorting of selected crushed stems into fractions, determining their length, weight, and humidity, were carried out in the laboratory. The length of the fractions of crushed stems was determined by the ruler. The value of the defined length of each particle of the stem was entered in the table. The number of stem particles that fit the selected size intervals made it possible to determine the frequency of occurrence of the event of particles in each interval. Data grouping was smoothed out by random fluctuations inherent in a small amount of data capable of storing the main, characteristic features of the collected experimental material in general. Determining the number and size of group intervals did not result in significant losses in relation to the process. Experimental data were grouped at intervals of the same size (50 mm) in the ranges of 0-50 mm, 51-100 mm, 101-150 mm, 151-200 mm, over 201 mm. Under such conditions, tables of all lengths of fractions of plant residues were compiled.
Our study was carried out at speeds of 7.45 km/h, 10.08 km/h, 13.6 km/h, 18.6 km/h, and 22.0 km/h. At each speed, three repetitions were made.
The weight of the package with selected plant residues, as well as the weight of individual fractions of crushed residues, was determined by scales in the laboratory.
The moisture content of raw materials was determined by a weight method according to DSTU ISO 6496:2005.
We analyzed the processes of grinding and processing plant residues by statistical methods according to [15].The analysis involved a sample of stem particles, which were formed in certain predetermined ranges: 0-50 mm, 51-100 mm, 101-150 mm, 151-200 mm, over 201 mm. According to the results of the research, graphical dependences were built, where the axis of ordinate hosted the quantity m n +1, which represented a dependent variable (where n is the full sample volume, m is the average rank value determined for each value of the stem particle). The axis of abscissa hosted the intervals of groups of particles of crushed stems. Since the plot of the accumulated probability determines the probability that the variable «equals, or less than», the value of the dependent variable was marked above the upper limit of each interval.

1. Designing and fabricating a roll crusher with the angles of inclination of cutting knives variable to the axis of rotation
In order to increase the efficiency of grinding coarse plant residues and reduce the energy intensity of the corresponding technological operations of grinding and processing crop residues that remain after harvesting corn, sunflower, rapeseed, and other crops, a roll crusher has been designed and manufactured.
The roll crusher has a frame ( Fig. 1), on which a stretcher is hinged through the fingers, where two drums with cutting knives are installed with the help of brackets, arranged along the entire width of the grip in a checkered manner. The knives can change the angle of inclination to the axis of rotation of the drum in the range of 5...20°, and the stretcher together with the drums can fall and rise in a vertical plane thanks to two hydraulic cylinders, which are fixed hinged. The specifications of the roll crusher can be found in Table 2. The number of knives in a row of drum 4 pieces 10 Knife sharpening angle 30°1 1 The angle of the knife to the axis of the drum 10°T he roll crusher of plant residues can work both as part of a trailer combined unit for grinding and processing plant residues, and autonomously, as a mounted machine assembled with a tractor.
The structural execution of knives of the roll crusher makes it possible to install them with external (right-side) arrangement) or by orienting the cutting edge of the knife inside the drum (left-side arrangement) (Fig. 2). This structural feature was used to determine the effect of the knife cutting edge orientation option (knife installation option) on the quality indicators of grinding and burying plant residues.

2. Results of determining the effect of additional weight on the quality indicators of grinding sunflower stems
Our study was carried out in order to determine the effect of additional vertical weight on the quality indicators of the technological process of grinding plant residues of sunflower with a roll crusher at the right-side and left-side arrangement of the knife cutting edge.

2. 1. Results of the study on the right-side arrangement of the knives of the roll
The roll crusher was additionally loaded with vertical force. The strength values were changed depending on the mass of the liquid with which the container was filled. The liquid tank was placed in the middle part of the symmetrically longitudinal plane of the roll. The experiments implied filling the container with water in the amount of 600 and 800 kg (5.88 and 7.84 kN) (Fig. 3, a).
The results of the experiment were used as a control in which the roll crusher at a speed of 7.2 km/h was assembled with the disc harrow BDVP-3.8 (manufactured at TOV Krasnyanske SP «Agromash», Ukraine). The tractor loading was 43.4 kf/m per meter of the unit's grip width. Under such conditions, the possibility of taking samples in the form of crushed stems, both after the roll and after the disc harrow ( Fig. 3, b, c), has been implemented. Each experiment was repeated three times.
We estimated the efficiency of grinding stems according to the accumulated frequency of events (the number) of the established sizes of stem particles in a certain range of their sizes. This length range is identical to the sizes defined for other experiments.  Tables 3, 4 give the percentage of crushed sunflower stems at a speed of 7.45 km/h at the right-side arrangement of the cutting edge of the knife. It was established that in the range of 0-50 mm, the percentage was 12.9 % per 600 kg of an additional load, 12.5 % for 800 kg, 18.6 % for the roll in a disc harrowing unit. The increase in the last experiment by almost 15 % of the values of particles of crushed fractions compared to others is due to the structural differences of the units that carried them out. The width of the tractor drive in the assembly of the roll crusher with a disc harrow is 1.35 times (full equipped weight, 1.38 times) larger than the indicators of tractor drives with a roll crusher.
The increase in the percentage of crushed stems in the range of 51-100 mm for a speed of 7.45 km/h was 25.8 % for an additional loading of 600 kg (it reached the level of 38.7 %). With an additional load of 800 kg -22.2 % (it reached 34.7 %). For a unit containing a roll crusher and a disc harrow, this indicator was 25.4 % (it reached 44 %). Note that the largest total level of crushed stems in the range of 101-150 mm is established with an additional load of the roll of 800 kg. An increase in the value of the additional loading force led to a corresponding increase in the percentage of crushed parts of the stems. The accumulated value of the percentage of crushed stem particles for this state of the roll exceeded by 1.58 times the corresponding value of the roll with an additional load of 600 kg and by 1.33 times for the assembly of the roll crusher and disc harrow.
Note that the largest total value of the percentage of crushed stems in the range of 0-200 mm was established when additionally loading the roll with 800 kg. These values were 1.13 times higher than the indicators of the roll with an additional load of 600 kg and 1.05 times higher than the unit in the assembly of the roll crusher and disc harrow.
In the range exceeding 201 mm, the increase in the percentage of crushed stems amounted to 600 kg -19.

2. 2. Results of studying a roll crusher with the rightside arrangement of the knife cutting edge
The distribution of sunflower residue fractions at the left-side arrangement of the knives of the roll is given in the summarized tables, which establish the corresponding indicators of the passage of the roll with an additional load of 800 kg (Table 3) and an additional load of 600 kg (Table 4).
Analyzing the results of the research given in Tables 3, 4, note that in the range of less than 50 mm, the highest percentage of crushed stem particles (31.6 %) was established at a speed of 22 km/h with an additional load of 600 kg. An increase in the additional load from 600 to 800 kg did not lead to a corresponding increase in the percentage of crushed sunflower particles at all the speeds studied. At a speed of 7.45 km/h, the percentage of crushed sunflower particles with an additional load of 600 kg was 14.5 % against 12.4 % with an additional load of 800 kg. At a speed of 10.08 km/h, the percentage of crushed particles was, respectively, 21 % with an additional load of 600 kg and 11 % for 800 kg. The percentages of crushed sunflower stems at a speed of 10.08 km/h with an additional load of 600 kg exceeded the corresponding indicators with an additional load of 800 kg. At a speed of 13.6 km/h, this ratio was 1.44 times, at a speed of 18.6 km/h -1.96 times, at a speed of 22 km/h -1.99 times, respectively.
An increase in speed both in terms of additional load of 600 kg and 800 kg led to a corresponding increase in the percentage of crushed sunflower stems.
In the range of 51-100 mm with an additional load of the roll of 600 kg, the largest percentage of crushed stems was established at 50.6 % at a speed of 13.  Table 3 Generalized results of studying the distribution of sunflower residues when using a roll crusher with an additional load of 800 kg  Table 4 Generalized results of studying the distribution of sunflower residue fractions using a roll crusher with an additional load of 600 kg  The largest total value of the percentage of crushed stems in the range of 0-100 mm was established at the right-side arrangement of the knives, with an additional load of 800 kg at a speed of 18.6 km/h -53.6 %.
In the range of 0-150 mm, we established the excess of the total (accumulated) values of the percentage of crushed stems with an additional load of the roll of 800 kg at the right-side arrangement of knives at all (except for the speed of 13.6 km/h) speeds studied. With an additional load of 600 kg, this pattern changed significantly. The roll with the left-side arrangement of knives in the range of 0-150 mm was characterized by greater values of the total percentage of crushed stems at almost all (except the speed of 10.08 km/h) speeds of experimental studies.
In the range of 0-200 mm, with an additional load of 600 kg, the roll with the left-side arrangement of knives was also characterized by higher total percentages of crushed stems compared to the right-side arrangement of knives. Thus, at a speed of 7.45 km/h, the accumulated value of the percentage of crushed stems in the range of 0-200 mm exceeded the corresponding indicators with the right-side arrangement of knives by 1.09 times. At a speed of 13.6 km/hby 1.09 times, at 18.6 km /h -1.04 times. At 22 km/h, this ratio was 1.04 times, respectively.
At a speed of 10.08 km/h, these indicators were almost the same (88 %, the left-side arrangement; 88.5 %, the rightside arrangement).
The additional loading of the roll with 800 kg changed the pattern of differences in the distribution of percentages of crushed sunflower stems for the right-side arrangement and the left-side arrangement of knives. There was no pronounced pattern of dominance of the knife installation direction in the pattern of changing the percentage of crushed stems. At a speed of 7.45 km/h, the total value of the percentage of crushed stems was the same (84.1 %). At the speeds of 10.08 km/h and 18.6 km/h, the rolls with the right-side arrangement of the knives were characterized by higher total values. This ratio was 80.3 % against 63 % at 10.08 km/h, 83.3 % vs. 76.3 % at 18.6 km/h. At 13.6 km/h and 22 km/h, the highest percentage of crushed stems were demonstrated by rolls with the left-side arrangement of knives. Accordingly, at a speed of 13.6 km/h-75 % against 77.6 %, and at a speed of 22 km/h, 85.7 % against 82 %at the right-side arrangement.
The energy costs for various installation of the cutting edge were not determined.

3. Results of studies to determine the effect of the arrangement of the knife cutting edge on the quality indicators of the grinding of sunflower stems
When analyzing our results (Tables 3, 4), we note that at the left-side arrangement of the drum knife at all intervals studied, there was an increase in the percentage of crushed fractions. Thus, in the range of 0-50 mm, the average value of the percentage of crushed fractions at the left-side arrangement of the knife was 12.46 % against 10.52 % at the right-side arrangement. In the range of 51-100 mm, the specified indicator was 34.7 % at the left-side arrangement and 30.2 % at the right-side arrangement, and in the range of 101-150 mm, respectively, 62.4 % and 52.9 %. Exceeding the percentage of crushed particles at the left-side arrangement of the knife compared to the right-side arrangement in the interval of 0-150 mm was about 18 %.
It was established that the percentage of sunflower stems crushed into fractions at the left-side arrangement of the knife at all intervals studied exceeded by 4 % the value at the right-side arrangement of the knife. It should be noted that these values were established with an additional load of the roll with a vertical force of 7.8 kN (weight 800 kg) at a speed of 7.45 km/h.

4. Results of studies on determining the impact of movement speed on the quality indicators of sunflower stem grinding
It was established (Fig. 4, a)that at the right-side arrangement of the knife, the percentage of crushed stems of the fraction up to 50 mm at a speed of 7.45 km/h was 12.5 %, at a speed of 10 Analyzing the results of our studies (Fig. 4, 5) we note that an increase in speed leads to a corresponding increase in the percentage of crushed stems in all defined ranges. This is especially true at the speeds of 18. 6

Discussion of results on determining the effect of additional weight on the quality indicators of grinding sunflower stems
Our studies showed significant prospects for the use of roll crushers in order to solve a problem to improve the quality of grinding of coarse-stem plant residues. Based on the results of examining a roll crusher, both in the mono version and in the disc harrow unit, it was established that the performance indicators of the technological process involving these machines are quite acceptable. Their application for grinding coarse-stem plant residues, which remain after harvesting corn, sunflower, rapeseed, and other crops, looks promising. When mechanically processing corn stubble, the degree of grinding of stems is an important indicator of the quality of the technological operation. The evaluation criterion used is the indicator of the number of non-damaged parts of stems longer than 5 cm, in which corn butterfly pupae can winter. From these pupae, adults are formed in the spring. It is worth noting that the corn butterfly is considered an extremely dangerous pest. Technological methods of dealing with it have not yet been sufficiently worked out. Therefore, modern technologies of cultivation of this crop provide for a series of operations aimed at grinding the particles of stems, followed by wrapping them to a sufficient depth (more than 10 cm).
In addition to green manure, intensive grinding of plant residues by roll crushers in combination with surface cultivation is very important when cutting rapeseed stubble. A thin layer of mulch on the surface draws moisture well and is favorable for the emergence of rapid shoots of carrion seeds. For farms with a high concentration of this crop, the roll crusher is as important a tool for maintaining a decent level of agriculture as for the reliable grinding of corn and sunflower stems.
It was found that an increase in the load of the roll at the right-side arrangement of the cutting edge of knives from 600 to 800 kg did not lead to a corresponding increase in the total value of the percentage of crushed stems. At a speed of 7.45 km/h, the roll crusher with an additional load of 800 kg demonstrated better performance compared to the corresponding indicators of the roll with an additional load of 600 kg. However, according to absolute total indicators, the percentage of crushed stems in the range of 0-150 mm and 0-200 mm, the roll with an additional load of 600 kg at a speed of 10.08 km/h demonstrated better performance. These indicators were, respectively, 72.6 % and 88.5 %.
It should be noted that for the speed of 7.45 km/h, which is the lowest value studied, the percentage of crushed stems in fractions increased much more dynamically than in experiments of relatively higher velocity values. This is natural, since at low speeds the conditions of contact (copying) by the knives of the roll crusher of soil relief are more stable. That is, the implementation of the technological process of grinding occurs under conditions when there is no (not significant) separation of individual parts of the roll crusher from the soil surface due to significant components of vertical dynamic excitations. At low speed values, stable vertical pressing force, which levels (extinguishes) vertical dynamic movements, the quality of grinding operations and, accordingly, the burying in the range of 101-200 mm of the crushed fractions of stems is the highest.
Note the absence of a pronounced pattern of dominance of the direction of installing knives on the total value of the percentage of crushed stems. However, the search and research in this direction should be continued while establishing the quality indicators of grinding coarse plant residues that remain after harvesting corn, sunflower, rapeseed, and other crops.

Conclusions
1. We have designed and fabricated a prototype of the roll crusher, in which the cutting knives are arranged along the entire width of the grip in a staggered manner with the ability to change the angle of inclination to the axis of rotation of the drum in the range of 5...20°. Lifting and lowering of drums with cutting knives in a vertical plane is carried out thanks to two hinged hydraulic cylinders.
2. The causal relations of factors that determine the system of formation of indicators of quality of grinding of sunflower stems and form the necessary prerequisites for determining rational modes and parameters of the roll crusher have been investigated. It was established that at the left-side arrangement of the cutting edge of knives, an increase in loading from 600 to 800 kg in the range of 0-50 mm did not lead to a corresponding increase in the percentage of crushed sunflower particles at all the speeds under study.
3. It has been noted that at the left-side arrangement of the cutting edge of the knives of the roll, the percentage of crushed stems in the range of 51-100 mm with an additional load of 600 kg exceeded the corresponding indicators with an additional load of 800 kg. This excess at a speed of 10.08 km/h was 1.9 times, at a speed of 13.6 km/h -1.44 times, at a speed of 18.6 km/h -1.96 times, at 22 km/h -1.99 times, respectively.
It was established that at the right-side arrangement of the cutting edge of the knives of the roll: -the largest total level of the percentage of crushed stems in the range of 101-150, with an additional load of 800 kg, exceeded by 1.58 times the corresponding indicators of the roll with an additional load of 600 kg, and by 1.33 times those of the roll crusher in an assembly with a disc harrow; -the largest total value of the percentage of crushed stems in the range of 0-200 mm with an additional load of the roll of 800 kg was 1.13 times higher than the corresponding indicators of the roll with an additional load of 600 kg and 1.05 times the roll in the disc harrow unit; -with an additional load of the roll of 600 kg, the largest total value of the percentage of grinding of stems in the range of 0-50 mm and 0-200 mm was established at a speed of 10.08 km/h, and, with an additional load of 800 kg -at a speed of 7.45 km/h.
No pronounced pattern of dominance of the direction of installing a knife on the total value of the percentage of crushed stems was established.
4. The percentage of crushed particles at a speed of 10.08 km/h and with an additional load of 600 kg was 1.9 times higher than the corresponding indicators with an additional load of 800 kg. At a speed of 13.6 km/h, this excess was 1.44 times, at a speed of 18.6 km/h -1.96 times, at 22 km/h -1.99 times, respectively. In the range of 0-150 mm, the highest (at the level of 75.3 %) value of the percentage of crushed stems with an additional load of 600 kg and the speed of 13.6 km/h exceeds by 1.19 times the corresponding indicators of the roll with an additional load of 800 kg and at a speed of 22 km/h. In the range of 0-200 mm, with an additional load of 600 kg, the roll with the left-side arrangement of knives was characterized by higher total percentages of crushed stems compared to the right-side arrangement of knives. At a speed of 7.45 km/h, the accumulated value of the percentage of crushed stems exceeded the corresponding indicators at the right-side arrangement of knives by 1.09 times, at a speed of 13.6 km/h -1.09 times, at 18.6 km/h -1.04 times, at 22 km/h -1.04 times, respectively.