Lozinskiy D. Proportional electro-hydraulic valve with the independent control of streams for mobile machines

Research object - working processes in proportional electrohydraulic valves. Research goal - reduction of power losses in the hydraulic drive of a mobile machine through creation of the hydraulic drive with independent control of streams. To achieve the goal, mathematical simulation of the processes in the proportional electrohydraulic directional control valve with independent control of streams was performed, taking into account its design features and operating modes, on the basis of nonlinear differential equations using numerical methods of their solution as well as experimental research of said characteristics at specially-designed stands. Scientific novelty consists in the following: for the first time the relationship was established between the response of the spool in the second stage of the directional control valve with independent control of streams and flow rate characteristics of the throttling elements and the first-stage valve response; for the first time an optimization criterion for the first stage of the directional control valve was developed, which makes it possible, on the basis of the functional, to provide maximal response and linear relationship between the displacement of the spool in the second stage of the directional control valve and the control voltage; mathematical model of the proportional electrohydraulic directional control valve with independent control of streams was developed that includes non-linear relationships between the losses through the diametric annual gap in the second-stage spool and through the valve-seat coupling of the controlled check valve; regularities were established of the influence of the first-stage throttling elements conductivity on the hysteresis value of the second-stage spool displacement dependence on the control voltage. Practical importance of the obtained results consists in the following: practical recommendations are developed on the choice of the design parameters, which make it possible to improve static and dynamic characteristics of the proportional electrohydraulic directional control valve with independent control of streams; directional control valve with independent control of streams and improved static, dynamic and power characteristics is designed; hydraulic drive circuit on the basis of the developed directional control valve is proposed, which provides high sealing degree for the hydraulic engine chambers and power losses reduction; new hydraulic drive circuit was designed for the loader "BOREX-2271" on the basis of the developed directional control valve with independent control of streams. Implementation degree: the results of the thesis are implemented at "BOREX"joint-stock company (Borodianka) and into the educational process at the department of Machine-building technology and automation of Vinnytsia National Technical University. Application field - machine-building.