Patent ID: 8567272

Claim:
A step actuator comprising: a housing; a stator in the housing; a rotor including a magnet provided radially inward of the stator and a nut member inserted into the magnet and protruding through one side of the housing; a bearing rotatably supporting the nut member; a screw member coupled with the nut member to linearly move as the rotor rotates; and a mounting member supported on one side of the housing to support the screw member in such a manner that the screw member is linearly movable, wherein the nut member includes an end portion passing through the bearing and a coupling portion extending from the end portion to couple with the bearing, and wherein the end portion of the nut member has an outer circumferential surface coupled with an inner circumferential surface of an inner race of the bearing, and the coupling portion is coupled with a lateral surface of the inner race of the bearing.