Cast crankshafts
AssigneeDaimler-Benz Aktiengesellschaft
InventorsHans-Joachim Schopf, Dietmar Lug
Life of this patent
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Abstract
A cast crankshaft with recesses or apertures provided in crank webs of the crankshaft and are formed in adjoining inner area of the casting material forming the main and crank pins by cores inserted therein prior to casting for the reduction of the weight and of the rotating out-of-round masses as well as of the counterweights thereof. A ratio of the smallest distance of the fillet of the crank pin from the outer surface line of the recess to the diameter of the crank pin lies between the values of 0.45 and 0.66, preferably at a ratio of about 1:2 with such distance being approximately as large as the distance between adjacent fillets at the crank and main pins from one another.
Claims14
A cast crankshaft at least a pair of crank web means, main pin means provided on respective sides of the crank web means, at least one crank pin means provided between the pair of crank web means and cast-in crank pin recess means provided at the crank pin means, the crank pin recess means being formed by core means inserted prior to casting of the crankshaft, characterized in that the crank pin recess means is delimited by a lower boundary surface extending approximately parallel to a longitudinal center axis of the crankshaft, at least one fillet means is provided at the crank pin means at a distance spaced from the boundary surface of the crank pin recess means, at least one further fillet means is provided at each of the main pin means with one of the further fillet means being disposed adjacent the fillet means provided at the crank pin means but spaced therefrom, a ratio of the smallest distance between the fillet means provided at the crank pin means and the lower boundary surface of the crank pin recess means to a diameter of the crank pin means lies between about 0.45 and about 0.66, and in that the smallest distance between the fillet means provided at the crank pin means and the boundary surface of the crank pin recess means is approximately equal to the predetermined distance between the adjacent further fillet means provided at the main pin means and the fillet means provided at the crank pin means.
Dependencies are inferred from the claim text.