International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The driving factor is an important technical feature of dynamical loaded working machines. It is especially important to know its value for the working wheel speed reducer of the rotating excavators. In this paper is presented a concept for determining the driving factor of a concrete gearbox speed reducer. To calculate the value of the driving factor according to the specified concept, knowledge of the load regime and the carrying capacity of the gearbox is necessary. The load regime is known from the load function, which is given in the paper, and is determined on the basis of the experimental measurements carried out for this purpose. The carrying capacity of the speed reducer is calculated by theoretical analysis according to the established methodology in this paper, for the characteristic pairs of gears determined in this analysis. As the most important gear pair, from the aspect of determining the driving factor, the most loaded gear pair is taken, in which during the exploitation of the speed reducer the most interventions are made, compared to the other gear pairs of the gearbox.

This paper presents the directions for load and safety appreciation of carrying structures component elements and their application to a particular object respectively carrying structure of rotating excavator working wheel. Load and safety of the carrying structure and its component elements are estimated based on the calculation of load and safety factors. The estimated load is based on the calculated value of load factors, while the safety by comparison of the calculated safety factors to the values of recommended minimum safety factors obtained by examinations of such structures in practice. With these indicators we have a situation where we are providing the static strength control of the analyzed elements. The paper presents numerical values of the load and safety coefficients for the excavator SRs-630 working in the coalmine "Suvodol" Bitola, for all characteristic working regimes in its exploitation lifetime. The numerical values of load and safety coefficients relate to clamps of the working wheel carrying structure and the most loaded joint of this structure.

As a result of the conducted theoretical and experimental researches of the local state of strains at the most loaded intersection of the clamps on the working wheel’s carrying structure in a concrete rotating excavator, an array of results has been attained. This paper represents systematically by means of diagrams the results of such researches under normal and specific working regimes of the excavator.

The specific working regimes during the entire exploitation life of the excavator account for about 1 %, with the excavator working in specific cases while digging under unpredictable working conditions. The experimental magnitudes of the strains are obtained with conducted experimental measurement in compliance with the established methodology for this purpose. The theoretical magnitudes of the strains are derived using the established mathematical model of clamps and applied computer FEM analysis.