Pumping-back type mechanical main shaft

The utility model discloses a pumpback type mechanical main shaft, which relates to the technical field of friction stir welding, aims to solve the problems that a plurality of welding flashes exist and a welding seam tail hole needs to be led out, and adopts the technical scheme that the pumpback type mechanical main shaft comprises a main shaft motor and a mounting seat, and a main shaft motor adjusting base plate is fixed on one side of the main shaft motor; the spindle motor adjusting base plate is fixed to one side of the mounting seat, a spindle rear end mounting seat is mounted on one side of the mounting seat, a mounting positioning sleeve is fixed to the peripheral side of the spindle rear end mounting seat, and a withdrawing shaft servo motor is fixed to one side of the mounting positioning sleeve. The main shaft motor is used for driving the stirring needle to rotate, the withdrawing shaft servo motor is used for driving the withdrawing shaft to move front and back, the limitation of a conventional