MEASURING METHOD OF PIN DIAMETER FOR CRANKSHAFT MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a measuring method of a pin diameter for a crankshaft machine capable of accurately obtaining a measured value by eliminating runout of the measured value from an outer diameter of a crank pin even if the position of measurement by a gauge is swung due to the revolution of the crank pin. SOLUTION: The outer diameter of a master workpiece is measured by using a gauge 36 in advance. The runout caused by a swinging movement of the gauge 36 is obtained on the basis of measured value of the master workpiece. An arithmetic expression representing the runout is stored into a memory 42. The outer diameter of a crank pin 18a is measured by using the gauge 36 when the crank pin 18a is machined while a crankshaft 18 is being turned around the axis L1 of a journal 18b. The runout stored in the memory 42 is subtracted from the measured value of the pin diameter using the arithmetic expression. By such a correction, the correct measured value of the pin diameter is obtained.