METHOD FOR HARDENING HELICAL CYLINDRICAL SPRINGS Russian patent published in 2017 - IPC B21F35/00 C21D9/02 F16F1/06 

FIELD: machine engineering.

SUBSTANCE: method involves winding the spring with a pitch exceeding the pitch of the finished spring, heat treatment, wheel blasting, lumo control, grinding of the ends of the heat-treated spring, compression of the spring until the coils touch. In the final stage, cold work hardening of the outer and inner surfaces of the compressed spring is carried out by blanking and cold work hardening of the compressed spring surface is carried out along the contact line of the coils by means of a hardening device when a compressed spring is located in a die hole. The cold work hardening of the outer and inner surfaces of the compressed spring is carried out by expanding the coils of the spring to the surface of the die hole with the punch entering it, wherein the diameter of the die hole is equal to the diameter of the compressed spring. The gap between the die hole and the punch surface is chosen less than the diameter of the coil spring by 0.2…5 mm. The cold work hardening of the compressed spring surface along the contact line of the coils is carried out by compressing the springs with a force of 5…300F₃, where F₃ is the spring force at maximum deformation.

EFFECT: increased productivity of hardening and the stability of the elastic properties of the spring.

3 cl, 3 dwg