A Drive for Transmission of the Rotational and Translational Motion to a Vacuum

Abstract

A drive is described that provides the rotation of a water-cooled rod at a speed of 0.2–30 rpm and its translation to a vacuum of up to 1 × 10^–6 Torr through a distance of 400 mm at a speed of 0.05–100 mm/min. The positioning accuracy is ±0.2 mm over the entire distance of the displacement. The transmitted load is approximately 100 kg. High accuracy and a wide range of rotational and translational speeds of the rod are provided by digital servomotors and a kinematic scheme of the drive, which eliminates the occurrence of bending moments on ball slideways and ball-screw assemblies. The reliable sealing of the rod is achieved using a plate bellows with a great stroke and a magnetic–liquid vacuum feed-trough to rotate the rod.