Thermometric diagnostics of elements of reaper drive for sunflower harvesting

Abstract

Ensuring failure-free operation of agricultural machinery in seasonal operation conditions is based on a maintenance system including diagnostics. A promising method of diagnosing the technical condition of mechanical transmission units is contactless thermometry based on measuring the intensity of infrared radiation of friction pairs. The purpose of the work is to verify the thermometric diagnostic method for mechanical transmission units of agricultural machinery. The results of experimental development of technology of thermometric nondestructive testing of the cardan joint of ZAFFRANI 940N reaper drive CLAAS TUCANO 570 grain harvester are presented in the work. The method of conducting the experiment included monitoring the temperature of parts and ambient air, the dynamic parameters of the reaper drive and the level of solar radiation. In order to implement the system approach, evaluation of the thermal state of the object of research was carried out at three hierarchical levels. The first level is represented by an analytical equation for determining the temperature in the friction zone. The second hierarchical level is implemented using CAE-technology, which makes it possible to establish the relationship of temperature in the friction zone and diagnostic temperature on the surface of the part. The influence of external heating factors at the third hierarchical level is due to solar radiation, which causes heating of the surfaces of the parts. To take this factor into account and compensate for the measured temperature values, a mathematical model of the thermal balance for the studied unit was developed, which includes thermal energy from solar radiation and energy supplied to the environment through convection and radiation. A summary of the results of the study confirms the effectiveness of thermometric nondestructive testing for mechanical transmission units using the example of bearing assemblies of the cardan joint of the reaper drive.

Temperature Conditions and Diagnostics of Bearings

“…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].…”

Procedure for Simulation of Stable Thermal Conductivity of Bearing Assemblies

“…When diagnosing the bearing, the measured temperature is compared with the limit value of 250°С [6]. The use of automatic temperature control allows the use of two diagnostic criteria -friction temperature in the wear zone and the rate of change of friction temperature in the wear zone [7][8][9][10]. The speed of temperature change in the friction zone can be the most important technical indicator of the change in the working state of the bearing units.…”