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.

Analysis of thermal dynamic micro-EHL considering bearing assembly temperature

To investigate thermal failure of dynamic oil film in cylindrical roller bearings(CRBs), based on the temperature field of CRBs, non-Newtonian dynamic thermal elastohydrodynamic (TEHL) lubricating performance in cylindrical roller bearings was conducted. A single surface bump was coupled with longitudinal waviness on the roller surface, and a dynamic non-Newtonian finite line contact TEHL model was established considering the boundary temperature of the bearing assembly. Effects of the roller boundary temperature, the surface bump amplitude, the rotational speed, and the viscosity-pressure coefficient on thermal failure were analyzed. Comparison of lubricating performance between Newtonian and non-Newtonian fluid was made as well. Results show that, when the roller boundary temperature increases, the pressure and the oil temperature become larger, and the film thickness and frictional coefficient decrease obviously for roller to outer race contact. As the surface amplitude is large enough, or the rotational speed is low enough, phenomenon of partial contact between the roller and the outer ring may be generated due to high boundary temperature of solids. In addition, when the rotational speed is very low, the temperature of the roller surface reaches the first critical temperature of the adsorbed film, so thermal film failure may occur for roller to outer race lubrication.

Investigation of Roller-Tape Contact Pair Used in Precision Mechatronic System

Smoothness of tape movement and stability of the tape area where elements are generated are very important in precision mechatronic devices where precise elements are generated on a steel tape, controlling them in real time. During movement, deformations and vibrations form in the steel tape area where elements are generated as a result of imperfections of movement equipment, contact between the roller surface and the tape, and errors arising in the movement process. This article is based on the need for a detailed theoretical and experimental research of the effects occurring during the movement of the precision steel tape used in measuring systems with precision elements generated on the tape, including an investigation of the roller-tape contact. The article also aims to develop a model of the system for measuring the displacement of the tape in a raster formation device, to investigate and assess possible effects of external and internal factors on steel tape parameters. The article presents experimental research conducted for determining dynamic variables forming during the movement of a steel tape, assessing the factors that may cause raster generation errors in dynamic mode.

A Method for Identifying Defects on Highly Reflective Roller Surface Based on Image Library Matching

Identification of the highly reflective surface defects on roller parts is a requirement to assure high quality of parts. However, the highly reflective roller surface has the reflection characteristics, which easily lead to the missed detection or wrong detection of defect targets in the visual recognition process. For this problem, a new identification method based on image library matching is proposed. First, to protect the edge information of the defect target while eliminating noise, preprocessing of the measured initial images can be accomplished by using the accelerated optimized bilateral filtering. Second, the entropy and grid gray gradient are used to achieve rough segmentation of highly reflective surface defects on roller parts. Finally, a defect fine identification method based on the Hu invariant moment matching integrated with morphological classification is proposed for achieving image library matching and further quickly removing the pseudodefects. Experimental tests were conducted to verify the effectiveness of the proposed method in achieving accurate identification of highly reflective surface defects on roller parts. The proposed method has an accuracy of 98.2%, and the running time can basically meet the requirements of real-time performance.

Influence of the shape of potato tubers on the quality of separation into fractions by the working bodies of potato sorting machines

Many agricultural producers are faced with problems of sorting flat and oval potato tubers into size fractions using roller sorting surfaces. The paper studies the influence of the shape of potato tubers on the speed of their orientation relative to the calibrating holes, and, as a consequence, the performance indicators of machines and the quality of the process performed. The aim of the study is to determine the causes of damage to tubers during sorting and ways to eliminate them. There was substantiated the relationship between the kinematic parameters of the roller surfaces of potato sorting machines and the shape of tubers, which makes it possible to reduce damage and improve the quality of sorting potatoes into fractions. A number of experiments were carried out to deter-mine the relationship between the shape of tubers and the kinematic parameters of the roller surface. In the first experiment, the number of tubers that will pass through the calibrating slot in a certain time was determined at different gear ratios in the drive of the rollers of the calibrating surface. In the second experiment, the time was found for a certain number of tubers of various shapes to pass through the calibrating surface. The graphs of the experimental dependences of the number of tubers of 43 mm thick passed into the calibrating gap between the rollers of 42 mm in 5 seconds on the ratio of the peripheral speeds between the rollers are presented. And the graphs of the dependence of the change in the time of passage of a group of tubers with a thickness of 40 and 42 mm through the gap between the rollers with a width 42 mm from the ratio of the peripheral speeds between the rollers are given. Based on the carried out studies, it was found that the ratio of the peripheral speeds of adjacent rollers, forming the calibrating slot, have a significant effect on the quality of the separation of tubers into fractions and are the cause of damage influenced by deformation. The presented analysis makes it possible to assess the influence of the shape of the tuber on the quality of the separation of tubers by roller calibrating surfaces of potato sorting machines, and also indicates the ways of improving the design of equipment for the finalization of potatoes after har-vest and before sale.