INFLUENCE OF THE MACHINING OF EDGES OF BLADES OF TRACTOR TORQUE COVERTER IMPELLERS ON ITS CHARACTERISTICS

Abstract

The production of impellers for hydrodynamic transmission of traction-transport machines is a complex technological task. Manufacturing of blades by punching with subsequent assembling and welding to toroidal surfaces ensures obtaining of specified angles of flow input and output, but does not provide an equidistant flowline of the working fluid in the intervane space, since the blades punched from sheet material have the same thickness along the length. Consequently, there is an increase in energy losses during the movement of the working fluid in the intervane channels and the coefficient of efficiency decreases. In the manufacture of impellers by casting provides the necessary spatial shape and variable in direction of flow thickness of the blade, but due to technological limitations, it is not possible to obtain the required thickness of the input and output edges. In addition, the forced turn cutting of blades eliminates the rounding of these edges. The required geometry of the edges can be achieved by their machining, but such an operation is undesirable due to its very high labor intensity. In large-scale and mass production, locksmithing operations should be excluded. In connection with said above, the question of level of influence of the impeller blade edges geometry on the characteristics of hydrotransmission is important. This article presents the results of experimental studies of the effect of machining of the torque converter impeller blade edges, manufactured by casting into the chill mold, on the efficiency coefficient and the converting properties of the hydrotransmission. The influence of blade edges machining is shown for each wheel separately and in aggregate. The conclusion is substantiated that the laborious operation of the metalworking of impeller blades' edges can be eliminated in the mass production of torque converters without significant degrading of the hydrotransmission characteristics.