CROSSKILL AND STAR-WHEELED ROLLERS. FUNCTIONAL AND DYNAMIC TESTS

Experimental field research of crosskill and star-wheeled rollers similar by design provides their developers and users with information on understanding their design and functional features. The purpose of the research is to compare the functional features of crosskill and star-wheeled rollers according to the criteria of clods breaking effect, compacting action, resistance to sticking in the range of pre-sowing and surface tillage depth. Methods and materials. Dynamic tests involved the study of three types of rollers. The research hypothesis assumed that the selected criteria for evaluating the work of rollers (intensity of breaking of clods, compacting action of rollers, intensity of bottom compaction and performance of rollers at high soil moisture) depend on roller pressure and different speed regimes, as they are derived from the shape of work surfaces. Sub-criteria studies were supposed to be carried out on the same type of soil: clods breaking characteristics on dry W = (10… 12) %, compacting effect on physically mature soil W = (15… 20) %, efficiency at high humidity - W = (25… 27) %. Evaluation of soil characteristics was performed by thermostatic-weight method according to the generally accepted method of "cutting ring" [Kaczynski NA, 1947], according to the volume of the cylinder 100 cm3. To determine the intensity of bottom compaction used the methodology and technical means of L. Pogorilyy UkrNDIPVT development. Statistical analysis of experimental data was performed by the method of analysis of variance according to [Dospekhov, 1985] and interpreted by standard computer programs Excel in the form of graphs. Results. The intensity of clods breaking with a classic roller is the lowest and depends on the speed of movement. The intensity of breaking by the modernized roller is approximately 1.1 times higher and with increasing speed is almost stable. The intensity of clods breaking by a specialized roller is the highest and almost (10...20) %, respectively, exceeds the previous two rollers and does not significantly depend on the increase in speed. The greatest compaction of the soil (the height of the layer to which the pre-prepared soil asked after the passage of the roller) is characteristic of a specialized roller, which is almost (1.5…1.7) times higher than the classic and modernized, respectively. Depending on the depth of pre-tillage (5…10) cm, compaction by rollers varies approximately twice. The greatest intensity of compaction of a bottom is provided by the specialized roller, and modernized and classical condense accordingly in (1,2…1,4) times below. The specialized roller sticks the fastest, which is facilitated by the 4-tier arrangement of working surfaces and their maximum in comparison with others contact with the ground. Sticking of the modernized roller surface is as that of the specialized. The classic roller surface remains clean for the longest time. Conclusions. The classic roller compacts both the upper and lower horizons of the soil well enough, brings little moisture to the surface, has a medium clods breaking effect, can be recommended for a wide range of works, but its primary purpose is cultivating after sowing; as a compromise it can be used for pre-sowing tillage with good quality indicators. The upgraded roller compacts the top layer of the soil well, carries away little moisture, mulches the surface, distributes the effort well at different depths of cultivation and can be recommended primarily for pre-sowing tillage; as a compromise solution can be used after sowing with good quality indicators. Specialized roller – star-wheeled, has good penetrating ability, works most actively, providing the best clods breaking effect, slightly carries away wet horizons on the surface; can be recommended for leveling and use on the soil after its main cultivation. Each of the studied rollers can be used to some extent in all these technological operations, but the best result will be achieved taking into account their characteristics, type and period of execution.