Prediction of angle error due to torsional deformation in non-circular grinding

Abstract

Non-circular grinding is used in the grinding of crankshafts. In contrast to general grinding, the precision in non-circular grinding is affected by torsional deformation, which results in errors in the grinding depth. In this study, an equation to detect the angle error caused by torsional deformation is established considering the grinding force, the structure of the crankshaft, and the distribution of torque. The angle error due to torsional deformation was found to be up to 0.44 arcsec, which is 5 % of the angle error obtained from previous studies. This difference occurred as the previous studies did not exclusively detect the errors caused by bending deformation and torsional deformation. However, the established equation detects these errors separately. The fundamental cause of the two errors is the change in the structure of the crankshaft caused by bending. Further, the errors were eliminated via steady rest to reduce the bending of the crankshaft. Although the proposed equation is not entirely error-free, the results obtained by the equation have higher accuracy than those of previous studies.