Servo stretching mechanism of thermoforming machine

A servo stretching mechanism of a thermoforming machine comprises a stretching head, a stretching rod and a stretching driving mechanism, and the stretching driving mechanism comprises a servo motor,a spline flange, a spline shaft, a lead screw, a nut, a stretching head lifting plate and a lifting guide mechanism. Wherein the servo motor is installed on an upper fixed plate of the thermoforming machine, the spline flange is rotatably installed on the upper fixed plate, the spline flange is in transmission connection with the servo motor, and the spline shaft is located in a key hole of the spline flange; the upper end of the screw rod is connected with the lower end of the spline shaft; the stretching head lifting plate is arranged on the lifting guide mechanism and is connected with thenut; and the upper end of the stretching rod is mounted on the stretching head lifting plate. By additionally arranging the transmission structure of the spline shaft and the spline flange, lifting and rotating of the lead scr