The effect of regrinding bearing surfaces on stresses in overlapped crankshafts

Regrinding the crankpin and/or the journal of a crankshaft changes the shape and most of the important dimensions. It reduces the overlap and increases the stresses in the crankpin and journal fillets. Strain-gauged model tests and finite element calculations for simply supported, single-crank throws have been carried out for four shapes: the standard design, reduced crankpin only, reduced journal only and both bearing surface diameters reduced by 5 per cent. Radial loading of the crankpin, pure radial bending and pure torsion have been applied separately. The stresses have been normalized with respect to the nominal bending stresses in the neck (the minimum section) between crankpin and journal fillets. The resulting stress concentration factors are reduced by regrinding.