Induction quenching method of gearshift shaft of change gear case

The invention relates to an induction quenching method of a gearshift shaft of a change gear case, which is characterized in that an inductor is a double-coil series inductor which is provided with an effective coil, wherein the effective coil is made of Phi 5*0.5 red copper tube and has the inner diameter of Phi 23 and the turn space of 2mm, a water spray ring is made of 12*10*1.5 red copper tube, has the inner diameter of 75mm and height of 12mm and is fixed below the effective coil, and therefore, the distribution of effective hardening layers can be controlled effectively, the overburningand melting of partial pointed parts or through quenching at thin wall part can be avoided, induction quenching of the two sides and the bottom of a groove and continuous distribution of the effective hardening layers are realized; the induction quenching quality of the spare part reaches the induction quenching technical requirement required by product drawings and using property requirement. The inductor has simple stru