200kw medium frequency induction heating machine, the best choice for quenching, deformation and tempering correction of spline sleeves

The material of a motor spline sleeve is 20Cr2Ni4 steel, the number of teeth is 6, the module m is 2.54mm, and the pressure angle is 30°. The technical requirements are: first, the hardness after carburizing and quenching is >58HRC; second, the spline sleeve The transmission torque is 25000N·m, and it is thermally socketed with the rotating shaft (interference fit), and is required to withstand 10kN pulling force without loosening; third, manufacturing accuracy, tooth shape tolerance <0.029rmm, tooth direction tolerance <0.015mm, ring gear radial circle The runout is <0.036mm, requiring small distortion after heat treatment to meet part accuracy and fit requirements.

Usually after carburizing and quenching of spline sleeve parts, the inner diameter of both ends shrinks, while the middle part shows large distortion, and the tooth shape and tooth direction distortion are out of tolerance. Correction according to traditional technology, using grinding processing. However, grinding is labor-consuming, time-consuming and costly; the grinding accuracy is poor, so that the spline sleeve and the rotating shaft thermal sleeve are easily cracked when assembled. Manual grinding has been used in production. However, although the price of manual grinding has decreased, the labor intensity of workers is high and the operating environment is poor. Moreover, the tooth shape and tooth direction deviation of manual grinding are often large, which cannot meet the technical requirements, resulting in assembly time. The mating contact surface is so small that it cannot withstand the test of not loosening under 110kN tension, so the manual grinding method is not applicable in production.

Zhengzhou Gou's uses a 200kw medium frequency heating machine to perform tempering correction to prevent carburizing and quenching deformation, so as to meet the accuracy requirements of parts and the technical requirements for assembly and torque transmission. The tempering correction method measures are as follows:

(1) Make a 45 steel dummy shaft matched with the spline sleeve.

(2) The spline sleeve is taken out after carburizing, quenching and tempering for 1 hour. Use a manual press to press the dummy shaft into the spline sleeve (hot sleeve) with a depth of 61.5mm (fitting section).

(3) Temper at 200℃x2h, and press out the dummy shaft after coming out of the furnace.

Using the above tempering correction method, the tooth shape and tooth direction tolerances of the spline sleeve meet the technical requirements. There is no cracking during hot-sleeving. After hot-sleeving, it cannot be pulled under a tensile force of 10kN, and the performance is excellent. The production operation shows that the spline sleeve parts treated by the above process are still running well after more than 3 years of operation.