Ball-screw device for robotic machine tool - performs synchronous rotation of ball-screw and ball-wedge nuts driving shaft when clutch is engaged

摘要

The axial line of the output shaft (35a) of the driving motor is parallel to that of the driving shaft (2). A ball-screw nut (5) is coupled directly to the output shaft. A ball-wedge nut (6) is coupled to a rotary shaft (18) with clutch-and-brake (22) connection to the output shaft. A predetermined ratio of transmission to one nut (5) is equated to a prescribed ratio of transmission to the other nut (6). Both nut rotations are monitored by a position detector (40). ADVANTAGE - A shortened device allows easy motor replacement without removal of nuts. Cumulative errors are avoided and high positional precision is insensitive to shock loads.