Simulation of a grain harvester threshing drum resource

. A significant part of agricultural machinery has a seasonal nature of operation, when sudden failures are extremely undesirable. Proceeding from this, modeling the real operating conditions of bearings in design calculations is relevant, and the novelty of solving the problem lies in the use of modern target computer-aided design programs for this. Research goal. Theoretical determination of the service life of agricultural machinery bearings using targeted computer software, taking into account the real conditions of their operation. Making recommendations of a structural nature to eliminate factors that accelerate bearing wear and increase reliability. Methods. Mathematical modeling of the operating conditions of the bearings of the threshing drum of a combine harvester using the target software. Results. The article presents the main reasons for the premature failure of the bearing units of agricultural machinery, considers the types of methods used to calculate and simulate the operating conditions of rolling bearings, taking into account the specifics of machines and mechanisms in which they are used. On the example of the threshing apparatus of a combine harvester, an evaluation characteristic of the adaptation of the existing computer software applications for the calculation of bearings to the operating conditions of agricultural machinery has been carried out. The most reliable software application was selected, which takes into account the maximum number of factors influencing the service life of the bearing assemblies. The reason for the discrepancy between the values of the calculated and actual service life of the bearing assemblies of the threshing drum of a grain harvester is determined, which is due to the still unaccounted temperature deformation factor (drum shaft elongation), which leads to the disappearance of the thermal gap between the rings and rolling elements of the bearings decrease in the efficiency of the nodal seals. Conclusions. 1. The established dependence of the influence of the change and the difference in temperature of the constituent elements of the threshing apparatus unit on the durability of the bearings. It was found that when the difference between the temperatures of the bearing housings and the threshing drum shaft is more than 20 ° C, the thermal gap between its rings and the rolling elements disappears due to the thermal elongation of the drum shaft, which leads to the opening of the seal joints, and therefore to a decrease bearing life. A structural solution is proposed for the modernization of bearing assemblies, which achieves the leveling of the negative impact of thermal elongation of the shaft with minimized interventions in the base structure and associated material costs. A similar solution can be used in most agricultural machinery mechanisms, where, due to low rigidity or for other reasons, it is impossible to have a stable mutual arrangement of components rotating on bearings.