Analysis of Bearing Assemblies Refit in Agricultural PTO Shafts

Abstract

The paper analyzes the problems of the most commonly used cardan shafts in agricultural machinery through a theoretical review and tests on a laboratory test bench. The aim of the research presented in this paper was to define the justification of a new method for retrofitting universal joint bearing units compared to the traditional methods of retrofitting. The new approach is based on energy efficiency (saving energy, raw materials and labor) compared to the conventional methods of retrofitting. The presented investigation to justify the proposed refit was carried out after the investigation of the extent of damage to the elements of the bearing assembly, which lasted 4.02 minutes per sample, with the aim of obtaining information essential for the purpose of our work. The proposed diagnosis and refit of the cardan bearings can help to extend the service life and improve the reliability of the universal joint shafts already in service. The results of the research have shown that the method with replaceable bushings (installation of undamaged surfaces in the load transfer zone) is 6.24 to 7.54 times cheaper than the complete repair of the elements of the bearing assembly, 2.11 to 2.83 times cheaper than the refit method, in which the damaged joints are replaced with new ones, and 1.62 to 2.74 times cheaper than the purchase of new double PTO (Power Take-Off) shafts.

Temperature Conditions and Diagnostics of Bearings

“…The size of the heat loss is an indirect feature characterizing the technical state of the friction pair, therefore, the thermal mode of the mechanical transmission unit can be used to diagnose its state. In addition, the result of exceeding the limit temperatures will be a violation of the normal lubrication mode and the transmission unit will enter the limit state [4][5][6][7][8].…”