METHODS OF DIAGNOSING HYDRODRIVE TRANSPORTATION AND TECHNOLOGICAL MACHINES
This method refers to a functional diagnosis methods of hydraulic drives and is designed to determine their overall technical condition and remaining life in the process of transport and technological machines on a functional purpose (for example, forest machines). The method is based on the characteristics of the random process of change of pressure in the hydraulic drive, resulting in the interaction of working organs of the car with the subject of work - tree. Experimentally we obtained normalized correlation functions and normalized spectral density of loading hydraulic delimbers when processing trees of various diameters with different operating time periods. The analysis of the graphs of the normalized spectral density shows that operation on various size sites is available for two distinct zones of maximum values. The maximum spectral density are shifted to higher frequencies with a decrease in size of a tree. By increasing the operating time of the machine we observed the shift of the maximum, thus, the high frequency maximum is shifted towards lower frequencies and low frequency maximum is shifted towards high frequencies. As a diagnostic parameter we selected the normalized spectral density as the most informative indicators, with clearly defined maxima, changing in the event of failure of a component of hydraulic drive. The technical condition of the hydraulic drive is estimated by the deviation of the maxima of the normalized spectral density of loading hydraulic drive of the reference values. The comparison of normalized spectral density maximum values of hydraulic drive loading under study with the hydraulic drive of limit state (intended for culling) is used to determine the possibility of the machine further exploitation. This method of functional diagnostics of hydraulic drives for the indirect failure detection in their elements in determining the level of technical condition and evaluating the suitability for further use. With this method it is possible to determine only the general technical condition of the hydraulic drive (whether there is a defective element in the hydraulic drive). In order to define a failure of a certain element (pump, hydraulic drive, pressure hose, etc.) it is necessary to examine this particular element.