OPERATION CONDITION RESEARCH IN HYDROMECHANICAL AUTO-

OSCILLATORY SYSTEM

L.S. Ushakov Orel State Technical University

Wide use of hydraulic drives in modern machinery created prerequisites for elaboration and creation of powerful and compact percussion (pulse) devices assumed as a basis of executive units of mining, metallurgical, road and municipal machinery. In hydraulic percussion devices occurs a transformation of continuous working fluid flow formed by pump station into oscillatory (cyclic) motions of a head which in the end of the travel performs percussion interactions with a waveguide or with the shank of the instrument used. The requirement in realization of percussive powerful loads to perform various technological operations resulted in elaboration of the considerable amount of percussive device models ( more than 300).

The operation of high-frequency hydraulic hammer is based on agitation of autooscillatory motions of functional elements. Such devices for a stable operation require a thorough tuning of a power pulse system, account of factors in operating fluid viscosity change, temperature conditions and an optimal ratio of input parameters of the hydraulic drive.

But, up till now there are no special test benches and machinery allowing to carry out investigations of such hydraulic percussion system with the use of modern technical measuring and control means of parameters. In view of this in the Orel State technical University there was elaborated a machinery complex DPM-1 consisting of the following functional subsystems: electrical, hydraulic, mechanical (percussive), control, diagnostics and visualization of information.

Fig. 1 Scheme of the experimental complex DPMI:

1,2 - converter of overpressure of type; 3 - microphone; 4 - power unit; 5 - analog - digital converter; 6 - PEVM; 7 - test bench with hydraulic percussive system

Unit of equipment is also aimed for carrying out researches for an auto-oscillatory system stability, an operation condition optimization for pulse hydraulic drives, hammering power transmission to a object to be destructed and for other problem solution.

Processes, which occur in hydraulic machines of a percussive action, are characterized with a quick parameter change in the course of time, availability of high values exceeding nominal ones several times as much, with high pressure, percussive loads. Hence, presentation of analog signals in digital form simplifies recording, saving and processing of experiment results. With the aid of mathematical modeling and statistical working programs (LabView, Matlab, Statistica) in a measuring system of the equipment unit DPM-1 one carries out an analysis of data obtained.