SUBSTANTIATION OF THE RATIONAL DESIGN FOR THE MINING HOIST’S DRUM

Rigidity requirements are higher for the split drums of mine rope hoists, since during the operation of the machine one of the  ropes passes through the gap between the drum parts, while the gap must not widen by more than 5 mm. One of the reasons  for the expansion of the gap is the deformation of the adjustable (narrow) part of the drum caused by the force applied by the  brake pads, which expand the drum from the inside. Determining the stress-strain state of the adjustable part of the split drum  of the mine hoist, including by the method of mathematical modeling, is a relevant task.The purpose of the study is to substantiate the rational design for the adjustable part of the split drum of the mine hoist from  the point of view of ensuring sufficient rigidity at a minimal mass. The rigidity should be such that the gap between the drum  parts due to deformation caused by the force applied by the brake pads does not widen beyond the allowed limit.We built three finite element models of the adjustable part of the drum for different designs using the «Lira» software package:  with one plate near the end; with one plate near the brake rim; and wider drum with two end faces (plates). For these models,  we obtained isofields of displacements along the axis of the drum shaft and equivalent stresses (according to Mises) under the  action of a uniformly distributed load in the contact zones of the brake rim and the brake pads. The braking moment created by  this load corresponds to three times the maximum static moment in accordance with the Safety Rules in Coal Mines.Based on the analysis of the modeling results, we concluded that for mine hoists with a split drum and internal pad brakes,  from the point of view of ensuring the permissible expansion of the gap between the drum parts, for the adjustable drum with  a single plate the rational design choice is to install the latter next to the brake rim. In this case, the expansion of the gap  exceeds the norm by only 13.4 %, but the mass is lower by 25 % in comparison with the two-plate drum design. In addition, installation of the  second face requires an increase in the  width of the drum.