Abstract: An object of the present invention is to provide an electric actuator having a structure capable of reducing an external force or impact acting on a screw shaft when a piston rod is at a stretched position. An electric actuator includes a nut, a piston rod, recesses, keys, holes, and a tapered portion. Into the nut, a screw shaft is screwed. The piston rod moves linearly via the nut. The recesses are formed on an outer circumferential surface of the nut. The keys are each provided to a recess. The tapered portion is formed on an inner wall of the cylinder body. The piston rod advances to move the keys outward to cause the keys to fit to the tapered portion to block retraction of the piston rod.

Abstract: An object of the present invention is to provide an electric actuator having a structure capable of reducing an external force or impact acting on an screw shaft when a piston rod is at a stretched position. An electric actuator 1 includes a nut 5, a piston rod 4, recesses 6, keys 7, holes 8, an a tapered portion 9. Into the nut 5, a screw shaft 3 is screwed. The piston rod 4 moves linearly via the nut 5. The recesses 6 are formed on an outer circumferential surface of the nut 5. The keys 7 are each provided to a recess 6. The tapered portion 9 is formed on an inner wall of the cylinder body 2. The piston rod 4 advances to move the keys 7 outward to cause the keys 7 to fit to the tapered portion 9 to block retraction of the piston rod 4.