Rodless oil extraction device driven by underground permanent magnet linear motor

The invention relates to a rodless oil extraction system driven by an underground permanent magnet linear motor. The rodless oil extraction system is composed of a front piston pipe, magnetic steel and a tail pipe. The front piston pipe is located at the uppermost end of the system and plays the roles of balancing pressure difference and preventing sand; the magnetic steel is located in the middle of the system, and the magnetic steel is powered by a cable to generate magnetic pumping so as to drive a rotor to linearly move in a reciprocating mode; the tail pipe is located at the lower end of the system and plays the roles of limiting the rotor and preventing sand for the motor; a pull-down oil well pump barrel is connected with the front piston pipe in a threaded mode, a pull-down oil well pump plunger and a motor pull rod are connected through a conversion connector with a pin, a pull-down oil well pump upper coupling is connected with an oil tube, an electronic rotor drives the pull-down oil well pump plunger to pump oil, and crude oil enters the oil tube from the pump barrel. According to the rodless oil extraction system, oil extraction without a pumping rod is achieved, and the rod pipe eccentric wear problem which can not be solved in a directional well is solved fundamentally; zero transmission from the motor to an oil well pump is achieved, stroke loss is eliminated, pumping efficiency of the oil well pump and system efficiency are improved, and operation safety risks are reduced.