BALL SPEED REDUCER AND ROTARY TABLE DEVICE USING SAME

摘要

A ball speed reducer rigidly rotatable at high speeds and suitable for a reduction in size and weight and a rotary table device are provided. An index table (10) is formed by securing a table (50) to the upper surface of the worm wheel (30) of the ball speed reducer (20). When a worm gear (22) is rotated according to the rotation of the input shaft (24) of the ball speed reducer (20), balls (36) made of a magnetic material are moved along the spiral ball groove (26) of the worm gear. The worm wheel (30) is rotated when the balls (36) are moved, and the table (50) is rotated. Since the balls (36) are attracted and held to the worm wheel (30) by permanent magnets (34), a case for preventing the balls (36) from falling off the worm wheel (30) can be eliminated. Therefore, the overall size and weight of the ball speed reducer can be reduced. Also, since a backlash is not required, the ball speed reducer can be rigidly rotated at high speeds.