| 摘要 |
<p>Disclosed is an electric actuator wherein a ball-circulating mechanism is simplified, increasing reliability, and wherein the number of parts and the number of machining man-hours are decreased, decreasing costs. A ball-screw mechanism (8) is linked to a speed reduction mechanism (6), is supported non-movably in the axial direction and rotatably via a rolling bearing (19) fitted to a housing (2), and is configured from a nut (16) wherein a helical thread groove (16a) is formed on the inner perimeter thereof, and a screw axle (15) that is inserted into the nut (16) with balls (17) therebetween and that is coaxial to a drive shaft (7). In the screw axle (15), a single-wound thread groove (15a) around the outer perimeter, and, separately from the this, a ball-circulating groove (22) that twists in an S-shape in a closed loop are formed. The screw axle (15) is supported movably in the axial direction and non-rotatably with respect to the housing (2) by means of: a parallel key (12) that engages a key groove (13) formed in the housing (2) and fits around the screw axle (15); a bushing (11) fitted to the housing (2); and the ball-circulating groove (22).</p> |
