Hydraulic linear drive

摘要

The hydraulic linear drive consists of a double-acting hydraulic cylinder (10), on one piston-rod side of which a thread (15) is formed on which a nut (16) sits. On a widened part (16A), the nut (16) has an external helical tooth system (17) which meshes with a corresponding gear (19) on the drive shaft of an electric motor (20). The nut (16) is arranged with slight play between two bearing surfaces and upon axial displacement actuates hydraulic control means (27, 28) via which pressure medium is passed from a pressure-medium source to the pressure spaces (11, 12) of the hydraulic cylinder (10). In this way, a hydraulic/mechanical feedback with self-locking is obtained, i.e. the hydraulic cylinder can no longer be adjusted in the event of the hydraulics or the electric motor (20) failing. <IMAGE>