Numerical and experimental investigation of transients in hydraulic systems. A possibility of rotor unit wear detection of axial piston pump based on measurement signals time-frequency analysis in the present study is described. Spectral Power Density PSD, Short-time Fourier transform STFT and generalized Wigner-Vill algorithm WVD were used for this purpose. The axial piston pump with the swinging plate, in which the good and the worn rotor unit were mounted, has been tested.

Two-stage pressure relief valve controlled with a piezoelectric stack. In this article one of the few developed solutions of the proportional indirect pressure control valve, with a piezoelectric stack used to control the valve, has been presented. In this paper the most interesting results of the tests for the valve variant equipped with the low voltage piezoelectric stack have been presented.

Calculations of hydraulic lines compensation mounted on tankers. In the paper the FEM analysis of main lines of U-type expansion loops mounted in the hydraulic central loading system installation on product and chemical tankers has been presented. The axial forces problem in installations mounted along of ship’s open decks executed from hull deformations stresses is given. The principles and advantages of use of the compensation of hydraulic lines have been described.

Laboratory researches of the hydraulic force generator. The stand for static and dynamic tests of press, anchoring blocks, anchorages as well as prestressing elements, which used hydraulic force generator has been described. A regression function describing power of the electric motor, depending on the chosen design parameters of the generator has been proposed. Experimental studies have been carried out and the regression coefficients have been determined.

Application of the proportional control in the hydraulic systems of the mechanical shovels. The article has described briefly all the operating functions as well as the construction of the hydraulic system in a standard mechanical shovel. On the example of the hydraulic system of hydraulic excavator, the system of the proportional control has been introduced. By means of the hydraulic schemes, the primary functions and the benefits of the proportional control in excavators have been presented.