ANALYTICAL SUBSTANTIATION OF THE STRUCTURAL PARAMETERS OF THE TECHNICAL CONDITION OF THE FIVE-PLUNGER SUPPORT OF AXIAL-PISTON HYDRAULIC MACHINES

Abstract

The purpose of the work was to provide an analytical justification of the structural parameters of the technical condition of the annular support of the five plungers, which could be used to evaluate the further use of the plunger pair in the technological process of repairing the axial-piston hydraulic unit. To achieve it, the first step is to analyze the operating conditions of the fifth plunger of the pumping unit of the hydraulic machine, which is a hydrostatic bearing, which allows to reduce mechanical losses in friction pairs at the expense of some increase in volumetric losses provided for by design solutions. At the same time, it is noted that the change in the structural parameters of the ring support of the heel as a result of hydroabrasive wear leads to an increase in the gap in the friction pair and causes an increase in volume losses of the working fluid. The analytically obtained relationship between the height of the annular support of the heel of the plunger, the gap in the coupling and the pressure of the working fluid relates the change in the height of the annular support to the size of the gap between the annular support of the heel and the support of the cradle for a hydraulic pump or an inclined washer for a hydraulic motor, which indicates the possibility use as a structural parameter to control the ring support of the heel of the plunger its height, subject to uniform wear. To determine the volumetric losses of the working fluid, which are formed by increasing the gap between the ring support of the heel and the support of the cradle, a dependence was analytically obtained. It was determined that the losses of the working fluid between the ring support of the heel and the support of the cradle do not significantly affect the volumetric efficiency of the transmission and can be compensated by the booster pump. The obtained quantitative assessment of the wear of the height of the ring support of the heel can be used to normalize the height of the support during direct diagnostic work when determining the technical condition of the plunger heel.