| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an induction hardening method of a crank shaft capable of reducing distortion of pin parts after hardening all pin parts, and suppressing the bend of the crank shaft when hardening of all journal pars is completed after hardening all pin parts. SOLUTION: The heating start time T1 of two pin parts (for example, P1 and P4 on the outer side) located on both end sides in the axial direction out of a plurality of pin parts (for example, four pin parts P1-P4) disposed along the X-direction of the axis of the multi-cylinder crank shaft (for example, four- cylinder crank shaft) with spaces therebetween is set to be earlier than the heating start time T2 of a plurality of pin parts (for example, pin parts P2 and P3) located between these two pin parts, and the heating finish time T3 of all pin parts P1-P4 in set to be the same, and distortion of the pin parts P1-P4 is reduced thereby.</p> |
