JP2018040483A5 - - Google Patents

Claims (6)

An electric motor, a ball screw that transmits the rotational force of the electric motor, and a housing that houses the ball screw;
The ball screw includes a screw shaft extending in an axial direction and having a spiral groove formed on an outer peripheral surface; a nut having a spiral groove formed on an inner peripheral surface thereof opposite to the spiral groove of the screw shaft; and a spiral of the screw shaft. A plurality of rolling elements that are movably loaded in a rolling path formed by a groove and a spiral groove of the nut, and mounted on the nut, the rolling element is circulated back from the end point of the rolling path to the start point. A circulation member in which a return path is formed, and a cover member that covers the circulation member;
On the inner peripheral surface of the housing, a groove portion is formed along the axial direction that engages with the cover member, restricts rotation of the nut in the circumferential direction, and allows the nut to move in the axial direction .
A ball screw actuator characterized in that a cross-sectional shape perpendicular to the axial direction of the groove portion is a rectangular shape or an arc shape .   The ball screw actuator according to claim 1, wherein the cover member is made of synthetic resin.   The ball screw actuator according to claim 1, wherein a cross-sectional shape orthogonal to the axial direction of the cover member is a rectangular shape or an arc shape. The ball screw actuator according to claim 1, wherein a plurality of the groove portions are formed in pairs at positions facing each other in the circumferential direction . The flat portion on the outer peripheral surface of the nut is formed, the circulation member and a ball screw actuator according to claim 1 wherein the cover member is mounted et the to the flat portion. Wherein the housing, a ball screw actuator according to claim 1, limiting unit for limiting the movement of the axis of the nut is kicked set.