Assessment of the influence of the working fluid production on the output parameters of the transmission hydraulic motor of the front loader

Abstract

Problem. During the operation of the volumetric hydraulic drive of the front loader, as the surfaces of the movable interfaces of the hydraulic drive elements wear out, the gaps increase, and as a result, the leaks of the working fluid (WF) increase, and, therefore, the performance of the machine as a whole decreases. The resource of the hydraulic drive units is largely determined by the physicochemical properties of the WF, and in particular, the ability of the WF to reduce the specific load in the contact of the surfaces of the movable joints. During the operation of the transmission hydraulic drive, the aging of the fluid occurs. As a result, its operational properties deteriorate, including a decrease in the bearing capacity of the WF lubricant film. This leads to an increase in the wear of the interface surfaces of the volumetric hydraulic drive of the transmission (VHDT) and a decrease in the productivity of the machine. Goal. Experimental studies of the influence of the working fluid production on the rate of change of the volumetric efficiency of the hydraulic motor of the volumetric hydraulic drive of the front loader transmission have been carried out. Methodology. The tests of the MP-90 hydraulic motor were carried out at the stand. The object of the study was the hydraulic motor of the MP-90 frontal loader. Hydraulic oil MANITOU HUILE HYDRAULIQUE ISO HV46 with different operating time was used as the WF. Samples were taken from the transmission drive system of the PMTS-1200 front loader. The experimental ones were carried out under the following conditions: WF temperature, t = 323 K; rotational speed of the pump drive shaft, n = 25 s ; the operating time of the WF varied within the range of T = 0–720 motor-hours with a step of 200 motor-hours; the purity of RZ is not less than 10 class according to GOST 17216-2001; the test time was taken equal to 40 hours; pressure in the discharge line 26.5 MPa, vibration amplitude 6 MPa, vibration frequency 0.2 s. Results. It is shown that an increase in the operating time of the WF during the operation of the machine determines, other things being equal, an increase in the rate of change in the volumetric efficiency of the VHDT hydraulic motor. Originality. To prevent increased wear of the moving surfaces of the VHDT interfaces during the operation of the front-end loader, it is necessary to use WF the bearing capacity of the lubricating film which is higher than the maximum permissible value. Practical value. The use of the results of the study will increase the VHDT of the hydraulic drive elements of the front loader and reduce the rate of decrease in its productivity during its operation.