Provision of allowance for the root and connecting rod necks and balancing of the forgings of the crankshaft of a heavy-duty vehicle

Abstract

The article discusses the requirements for balancing crankshafts. The unbalanced mass of the crankshaft after machining should be oriented in a certain angular sector, which ensures the removal of material in the opposite phase along the end surface of the counterweights. The existing calculation methods provide the specified imbalance conditions only at the design stage of the crankshaft forging by sorting through combinations of geometric accuracy indicators within the fields of their tolerances with simultaneous calculation of the position of the unbalanced mass. The method provides the design position of the unbalanced mass, but does not extend to the forging manufacturing process. The article considers the practice of machining production of changing the position of the machining base, which ensures the redistribution of masses. unprocessed elements of counterweights and the hit of an unbalanced mass in a given angular sector. Changing the position of the processing base completely redistributes the allowance for the root and connecting rod necks, which is not taken into account in the process of hot volumetric stamping of crankshaft forgings. The article presents a calculation scheme that allows taking into account changes in the position of the machining base, as well as mathematical dependencies that allow, according to measurements from the extreme trunnions of the crankshaft forging, to simulate the distribution of the allowance for the root and connecting rod necks from the machining base. Mathematical dependencies allow you to select the value of the adjustment displacements of the stamping equipment and ensure that there is an allowance for all angular phases of the main and connecting rod necks of the crankshaft forging.