METHOD OF SETTING DEPTH OF QUENCHING HARDENED LAYER OF CRANKSHAFT FOR MULTI-CYLINDER ENGINE, METHOD OF PRODUCING CRANKSHAFT, AND CRANKSHAFT

摘要

PROBLEM TO BE SOLVED: To provide a method of setting a quenching depth which can reduce bending and elongation in quenching a pin part and a journal part of a crankshaft for multi-cylinder engines.SOLUTION: A method of setting a quenching depth includes: first and second steps of grasping bending amounts and elongation amounts under a first reference condition of quenching pin parts and a second reference condition of quenching journal parts; third and fourth steps of grasping bending amounts and elongation amounts under a first modification condition of modifying the quenching depth of the pin parts individually from the first reference condition and a second modification condition of modifying the quenching depth of the journal parts individually from the second reference condition; fifth and sixth steps of determining rates of change of grasping bending amounts and elongation amounts for each modification condition relative to the reference condition; and a seventh step of calculating quenching depths for individual parts so that a bending amount and an elongation amount are minimized, on the basis of the rates of changes of bending amounts and elongation amounts.