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- Autors
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Kosolapov V.
- Issue
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Hoisting and transport equipment, 2025, №1(69)
- Pages
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38-49
- DOI
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10.15276/pidtt.1.69.2025.04
- Abstract
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The article analyses the influence of the state of the lubricating film of the hydraulic fluid on the performance of road construction machines with cyclic action with hydrostatic transmission, in particular, the PMTS-1200 front-end loader. The main attention is paid to the influence of the speed of performing work operations by the machine on the overall productivity. The machine power balance equation is used to determine the speed taking into account the engine power load.
An analysis of the factors that affect the performance of the loader shows that the key values are the flow rates of the hydraulic pump and the volumetric efficiency of the hydraulic motor. The determination of these coefficients is based on the change in working fluid leakage through the gaps in the piston pairs and the distribution pair of the pumping unit. These indicators were determined for the period with the minimum intensity of changes in the efficiency of the hydraulic pump and hydraulic motor, i.e. in the steady-state wear mode. A drop in their efficiency during run-in was also taken into account.
Experimental studies were carried out using MGE-46V hydraulic fluid, the properties of which are defined by TU 38 001347-83. The bearing capacity of the lubricating film was studied on a device with a ball-to-ball contact at different temperatures and loads. The results showed that the bearing capacity of the lubricating film decreases with increasing fluid consumption, with the greatest change occurring at a temperature of 293 K.
The wear of friction surfaces was studied on a four-ball friction machine MAST-1.
It was found that the wear function is nonlinear, and the wear intensity increases by almost 65% with the increase in operating time in the range from 0 to 1000 hours. The dependence of wear on the bearing capacity of the lubricating film was determined by the graph-analytical method, which made it possible to model changes in the piston pair of the axial piston pump.
The calculation of the loader's performance showed that a decrease in the bearing capacity of the lubricating film leads to a significant, nonlinear decrease in the machine's performance. The larger the piston pair's azor, the faster the productivity decreases with a decrease in the bearing capacity of the lubricating film. Therefore, it is necessary to control the load-bearing capacity of the lubricant film to maintain high productivity of the loader.
- Keywords
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hydrostatic transmission, bearing capacity of the lubricating film, - hydromechanical efficiency, volumetric efficiency, wear, friction surface
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