LINEAR ACTUATOR AND OSCILLATION CONTROL DEVICE FOR RAILWAY VEHICLE

PROBLEM TO BE SOLVED: To provide a compact linear actuator with small back drive force which is unlikely to have solidification due to abrasion powder and an oscillation control device for a railway vehicle having the linear actuator.SOLUTION: A linear actuator comprises: a main body of a hollow structure having an opening end and a closed end; a cylinder having an opening end on the side of the opening end and fixed at the closed end of the main body; a direct-operated rod whose one end extends from the opening end of the main body and which has a wearing in the outer periphery of the other end and is housed in the cylinder slidably in the axial direction; a hollow shaft supported in the main body rotatably. The hollow shaft has a permanent magnet in part of the outer peripheral surface. A coil part in part of the inner surface of the main body and the permanent magnet configure a hollow motor. A nut part fixed in the hollow shaft concentrically and a screw part in the outer peripheral surface of the direct-operated rod are engaged together to configure a rotary direct operation conversion mechanism. The actuator has a rotary oil seal part which seals between the hollow shaft and the main body on both sides of the nut part in the axial direction.