Thermal diagnostics of mechanical gear elements of combine harvester

Abstract

The work carried out practical testing of the technology of thermal diagnostics of belt gear elements of the grating mill drive of the combine harvester. The basis of the technology is the principle of using the coefficient of the temperature ratio on the surface of the diagnosed unit and temperature in the friction zone, expressed through the coefficient of proportionality of the finite element model. The peculiarity of the thermal diagnostics, in this case, is to compare the temperature in the friction zone with the maximum allowable temperature for the direct contact zone in the mechanical transmission unit. The object of the study is the tensioning roller of the drive of the grating mill of the first stage of the CLAAS TUCANO 580 combine harvester with 6203-2RS TIMKEN bearings. The result of the numerical experiment showed a significant effect on the temperature in the friction zone of the operational parameters - radial force and rotational speed. The use of 3D-modeling made it possible to determine the key parameter of the proposed thermal diagnostics technology - the proportionality coefficient of the finite-element model k=0.489. The temperature of the bearing assembly of the tension roller was measured periodically, using a non-contact method during harvesting in the 2020 season. For the period of regular observations of 128 moto-hours, the value of the maximum temperature growth rate in the friction zone Vτ=0.025 °C/min and the maximum temperature in the friction zone 69.5 °C, taking into account the ambient air temperature, were determined. No failures of the diagnosed unit were found. In the process of application of thermal diagnostics technology, no errors of the first kind are recorded, which indicates the effectiveness of the proposed technology.

Temperature Conditions and Diagnostics of Bearings

“…The friction zone temperature analytical model is based on structural, process and operational factors [13]:…”

“…Thermal diagnostics accuracy of bearing assemblies is affected by heating factors from ambient air, adjacent heat sources and solar radiation [9]. Therefore, diagnostics by the temperature measured on the outer surface of the bearing assembly has no practical application [10][11][12][13][14][15]. Modern technologies and technical means of temperature measurement make it possible to perform thermal diagnostics automatically, without manual labour, but only when measuring the temperature of the outer surface of the bearing assembly [16][17][18][19].…”