摘要 |
The invention relates generally to a step actuator, in which a lead screw coupled with a screw thread formed in a nut member is installed in a rotor magnet and moves back and forth in an axial direction responding to a rotation of the rotor to transmit power in an axial direction. A cylindrical bearing for rotatably supporting the nut member is disposed at an upper part of the nut member and integrally formed therewith, to fundamentally remove a gap in the axial direction in the coupled area between the cylindrical bearing and the nut member, thereby significantly reducing the feeding error of a rotator in the axial direction when the lead screw moves back and forth in the axial direction, and reducing the number of parts to be assembled to lower the material cost and the labor cost for assembly. |