Estimation of the Residual Operation Life Period of Mechanical Transmissions of Mining Machines by Means of Superficial Metal Hardness Measurement in Increased Wear Areas of Their Parts

The present paper contains a statement of basic provisions of the estimation method for the energy capacity of parts of mechanical transmissions of mining machinery. A method was substantiated for the assessment of the residual operation life period of large-pitch gears by means of regular hardness measurement of the superficial metal layer of the interaction gear surface. Patterns of gear hardness mutations of large-pitch gear transmissions were discovered. In order to investigate the influence of value and type of load upon the reduction of the operation life of the mechanical transmissions of mining machinery, an experimental fixture was built, and laboratory experimental work was done to study the destruction of non-standard elements. The strain parameters of the samples were determined, as well as local metal hardness changes in the areas adjoining the destruction spots. Crucial strain corresponds to the increased hardness with the limit value for the material given in the destruction area. In accordance with the experimental data, it was determined that the observed local hardness changes take place in areas where the stress is increased over the proportionality limit, and the work of the destruction forces assigned to the density of dislocations immediately adjoining the destruction plane is expressed as hardness increment, the latter being a constant value.