US Patent 8453530 Linear actuator

Linear actuator device, comprising a housing (2), an externally threaded screw (5) mounted to a piston (9), an internally threaded extended nut (7) and a motor (16) comprising a stator (33) and a rotor element (30) positioned around the extended nut (7), wherein a plurality of first magnets (31) of the rotor element (30) are positioned in relation to the stator (33) such that the stator (33) lies between the extended nut (7) and the first magnets (31) of the rotor element (30). The advantage of the invention is that linear actuators with a high energy density can be manufactured in an easy and cost-effective manner.