Wyniki 1-2 spośród 2 dla zapytania: authorDesc:"Oleh V. PIONTKEVYCH"

Study of the dynamic stability of the belt conveyor adaptive drive DOI:10.15199/48.2019.04.17

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Goods flows, arriving on the belts of the conveyors of various technological applications are characterized by considerable irregularity both regarding the amplitude of loading and goods supply intervals. Irregularity ratio of goods flows can vary within the range of Кn=1,97...2,02 [1]. For this reason the utilization factor of the conveyors, for instance, at mining enterprises, is on average, 50...70% by power and 60...70% by operation duration. The drives of agricultural mobile machines accept loads, the intensity of which differs greatly at different phases of the technological cycle [1]. Transverse conveyors and conveyor unloader of root-cutting machine in the process of the motor transport change, operating with the harvester, stop and beets are accumulated in the tank of the harvester. After the restarting of the conveyors drives the technological loading on the conveyors increases 2,5...3 times as compared with the nominal loading. Similar operation modes are typical for the receiving conveyor of clamp former in the process of root crops unloading into the hopper from the motor transport. In this case, the failure of drive’s elements in electro mechanic drive of the conveyor, and in hydraulic drive [2] - emergency outage as a result of safety valve operation and the shutdown of the hydraulic motor is possible. For further resumption of the conveyor operation the load at its working unit is manually decreased and the restarting of the drive is performed. Such operation modes of the conveyor cause unjustified electric energy consumption, wear of the belt, idlers, increase of the idle run of the belt, downtime of the equipment. That is why, numerous studies [3-5] are aimed at the provision of the coordination of the operation parameters of belt conveyors drive with variable modes of goods flows. One of the directions of the research is the study of drives operation with the regulators of belt motion speed a[...]

Experimental research characteristics of counterbalance valve for hydraulic drive control system of mobile machine DOI:10.15199/48.2019.04.18

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Introduction Mobile machines with hydraulic drive are widely used in industry, transport branch, agriculture [1-3]. Such machines, as a rule, are equipped with high variety of removable operating tools. It enables to use them during greater part of calendar year for performing various operations, such as digging, materials handling, loading operations with bulky materials. Systems of hydraulic drives control of such machines for energy saving, must provide the possibility of regulation of operation organs motion speed and working pressure of pumps in wide ranges. It is important to provide the reliable motion control of the executive device in case of alternating load. Hydraulic drives, based on spool hydraulic separators are widely used in mobile machines. In the process of operation such spools wear, this reduces the degree of leak tightness of hydraulic lines and complicates the operator’s control over the position of the executive device with the load. To provide the possibility of the control over the motion of the executive device and to decrease nonproductive power expenditures in case of the alternative loading counterbalance valves (CBV) are used in the hydraulic drives of mobile machinery. At the same time to provide high degree of leak tightness of operating hydraulic lines controlled check valves are used. Available CBV and controlled check valves increase the cost of the system of hydraulic drive control, its dimensions, mass and operation cost of the mobile machinery [1-7]. The authors elaborated the construction of CBV that simultaneously provides the possibility of the motion speed control of the executive device at the alternative loading and increases the leak tightness degree of the operating hydraulic lines of the hydraulic drive. The following problems are solved to realize the elaborated CBV construction:  provision of high degree of leak tightness;  statistic characteristics st[...]

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