Screw shaft feed mechanism and positioning control method therefor

Abstract

A screw shaft feed mechanism includes a screw shaft (25) rotatably supported by a frame (19) and extending in a shaft feed direction of a work table (shaft fed base) (1); a nut member (39) rotatably supported by the work table (1) and engaged with the screw shaft (25); a screw shaft drive motor (29) for rotating the screw shaft (25); and a nut drive motor (57) for rotating the nut member (39), wherein both screw shaft driving means and nut driving means are provided with a motor having a device detecting a rotational angle of a motor shaft, respectively. In a positioning control method for a screw shaft feed mechanism, the screw shaft drive motor (29) and the nut drive motor (57) are activated simultaneously; the screw shaft drive motor (29) and the nut drive motor (57) are deactivated in such a way that a time difference is produced between when the screw shaft (25) stops and when the nut member (39) stops; and the work table (1) is located by controlling deceleration of any one of the screw shaft drive motor (39) and the nut drive motor (57) which is stopped later. In this positioning control method, it is possible to locate the work table at high speed and simultaneously at high positioning accuracy.

Dependencies are inferred from the claim text.