A mechanism for driving a screw rod by supersonic vibration

摘要

A mechanism for driving a screw rod by supersonic vibrations, which may achieve space savings, prevent back-lash of a work rack, and effect smooth operation, is provided.;A first screw rod rotation device (16a, 16a', 16d, 16d') is provided for rotation of a screw rod (2) in a first direction, and a second screw rod rotation device (16b, 16b', 16c, 16c') is provided for rotation of the screw rod (2) in a second direction. The first screw rod rotation device (16: 16a, 16a', 16d, 16d') includes a first vibrator (7) contacting a groove portion (12) of the screw rod (2) at a specific angle, a first spring (8) urging the first vibrator (7) toward the groove portion (12) of a screw rod (2) at a specific pressure and a first piezoelectric actuator (6) for vibrating the first vibrator (7) upon electrical activation. The second screw rod rotation device (16: 16b, 16b', 16c, 16c') includes a second vibrator (7) contacting a groove portion (12) of the screw rod (2) at a specific angle opposite that for rotation in the first direction, a second spring (8) urging the second vibrator (7) toward the groove portion (12) of the screw rod (2) at a specific pressure and a second piezoelectric actuator (6) for vibrating the second vibrator (7) upon electrical activation. The first and second screw rod rotation devices (16) are directly mounted on the work rack (5) which surrounds the screw rod and is slidable in the axial direction of the screw rod.