TRANSFER APPARATUS PERMITTING MINUTE FEED AND SPEEDY FEED

摘要

PURPOSE:To permit positioning with high precision by screwing a ball nut with a ball screw shaft and permitting a transfer table connected to the nut to be fed minutely or speedily by permitting the relative revolution transfer or the transfer in the axial direction between the shaft and the nut. CONSTITUTION:A ball nut 29 having a driven gear 49 is screwed with a ball screw shaft 7 which is movable in the direction of revolution and fixed and axially supported in the axial direction onto a fixed bed 1. An outer cylinder 40 having a driving gear 47 is spline-fitted through steel balls 50 in the movable state in the axial direction and in the direction of revolution onto a ball spline shaft 8 which movably holds the ball nut 29 in the axial direction and in the direction of revolution and s axially supported rotatably onto the fixed bed 1, and two stepping motors 17 and 18 are connected to the shafts 7 and 8. The shaft 7 is revolved stepwise by a minute angle by controlling the motors 17 and 18, and the nut 29 is fed minutely or speedily for the shaft 7 by adding the amount of feed of the ball nut 29 or by the difference between the respective amounts of feed of the shaft and the ball nut by the drive of the motors 17 and 18.