Patent ID: 9156129
Filing Date: 2015-10-13
Classification: B24B

Abstract:
1. A grinding machine that grinds a workpiece by advancing and retracting a grinding wheel in synchronization with a rotational phase of the workpiece, comprising: a deflection degree acquisition unit that acquires a degree of deflection of an eccentric cylindrical portion of the workpiece during grinding based on a shape of the workpiece and a grinding condition, the eccentric cylindrical portion having a center offset from a rotation center of the workpiece, and a portion to be ground by the grinding wheel being the eccentric cylindrical portion; a first correction value computing unit that computes a first correction value for a command position of the grinding wheel relative to the eccentric cylindrical portion based on the degree of deflection; and a command position correction unit that corrects the command position of the grinding wheel relative to the eccentric cylindrical portion based on the first correction value, wherein the deflection degree acquisition unit comprises: a unit that computes a theoretical grinding efficiency by multiplying a grinding point velocity by a cut-in depth based on the shape of the workpiece and the grinding condition; a unit that acquires a real grinding efficiency during grinding; a unit that acquires a real pressing force in a cut-in direction, the eccentric cylindrical portion receiving the real pressing force from the grinding wheel during grinding; a unit that computes a sharpness coefficient that expresses a relationship between the real grinding efficiency and the real pressing force based on the acquired real grinding efficiency and the acquired real pressing force; a unit that computes a grinding force based on the theoretical grinding efficiency and the sharpness coefficient; a unit that acquires the real pressing force during spark-out, as a coolant dynamic pressure; a unit that computes a computed pressing force value that is a sum of the grinding force and the coolant dynamic pressure; a unit that acquires a stiffness of the workpiece; and a unit that computes the degree of deflection of the workpiece by dividing the computed pressing force value by the stiffness of the workpiece.