TAPERED ROLLER SCREW DRIVING APPARATUS

摘要

A driving apparatus has a roller screw member that includes a main shaft; a plurality of roller shafts projecting radially outwardly and upward ly at an angle from the radial direction of the main shaft and arranged at equally spaced intervals along a helical line around the main shaft, and a plurality of rollers rotatably mounted on the roller shafts. The rollers tapered to the angle are mounted on the roller shafts and oriented with the tapering inwardly to the main shaft thereby providing each roller with a bottom region of its tapered surface being perpendicularly oriented with the axis of the main shaft. The driving apparatus also includes a rail member adjacent and axially oriented with the main shaft of the roller screw member. The rail member includes a plurality of equally spaced projections having inclined upper surfaces adapted for radial engagement with the bottom region of the tapered surfaces of the rollers, the inclinati on of the projection upper surfaces being equal to that of the helical line of the roller shafts of the roller screw member. The angle of the tapering provides a sliding fre e engagement is determined to have a projected extension of the tapered roller bottom regions intersecting the axis of their respective roller shaft on the axis of the main shaft. The rollerscrew member is adapted for axial movement and the rail member is fixed against axial movement, the rotation of the main shaft provides the roller screw member to move in the axial direction of the main shaft with the roller tapered surfaces rotatably engaging the projection upper surfaces.