METHOD OF RADIALLY PRESSURISING THE BORE IN A CRANK THROW TO THE YIELD STRESS PRIOR TO SHRINK-FITTING IT TO THE MAIN BEARING PIN

摘要

A crank throw comprises two arms (1) and a crank pin (3). Each arm includes a bore (2) to be shrink-fitted over a pin portion on a main bearing pin. Before assembling the shaft, the bore (2) is subjected to a radial pressure of a level bringing the stress in at least part of the material surrounding the bore up on the yield stress of the material. After stress relaxation compression stresses remain in the material near the bore periphery, which reduces the resulting stress level in the assembled shaft.