PREDICTION OF THE MAIN GEAR LIFETIME OF BELAZ DUMP TRUCK AT THE DESIGN STAGE

The purpose of the research is to improve the method for calculating the lifetime of bevel gears with a circular tooth of the driving axle of the BELAZ dump truck with a hydromechanical transmission. An analysis of domestic and foreign calculation methods showed that when determining the contact stresses in the gearing, the influence of the modification of the side surfaces of the teeth on the magnitude of internal dynamic loads is not taken into account, which leads to a significant overestimation of the calculated lifetime of gears during their design. The solution to the problem is the introduction of refinement coefficients into the calculation methods traditionally used in OJSC “BELAZ”, the values of which are determined according to the recommendations of the Gleason company (USA), the supplier of gear-cutting equipment to OJSC “BELAZ”. Comparison of the actual value of the lifetime of the gear wheels of the main gear, established according to the results of the career operation of the BELAZ dump truck with a carrying capacity of 90 t with a hydromechanical transmission (about 142,000 km of run), with the results of calculating the lifetime using the proposed (134,000 km of run) and traditional (167,000 km of run) methods showed that the relative error in estimating the lifetime of the bevel gears of the drive axle of the dump truck, calculated by the proposed method, is about 6 %, and by the traditional one — 15.5%.