Drive Unit
AssigneeBosch Rexroth AG
InventorJoerg Dantlgraber
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Abstract
Disclosed is a drive unit, in particular for a closing unit, an injection unit, or an ejector of an injection molding machine. The drive unit comprises a double-acting force transmitting element provided with a small and a large piston unit which are disposed in a cylinder. The large piston unit is adapted to be pressurized by a great force both in input and in output directions. According to the invention, both the large piston unit with respect to the cylinder and the cylinder with respect to a movable element of the drive of the small piston unit are spring-prestressed.
Claims13
A drive unit, in particular for a closing unit, an injection unit, a slider, or an ejector of an injection molding machine, comprising a double-acting hydraulic force transmitting element comprising two piston units movable relative to each other with different active surfaces which confine, along with a cylinder, pressure chambers, wherein the smaller piston unit is preferably driven electrically and the cylinder, for applying a great axial force, is adapted to be fixed via a hydraulically actuated clamping means with respect to a frame of the machine, and a centering spring arrangement for centering the large piston unit with respect to the cylinder, and a prestressed pressure spring via which the cylinder is supported by a movable element of the drive.
Dependencies are inferred from the claim text.