Drive unit
AssigneeBosch Rexroth AG
InventorJoerg Dantlgraber
Life of this patent
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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.
Claims14
A drive unit comprising a double-acting hydraulic force transmitting element comprising two piston units, each including at least one piston, movable relative to each other with different sized active surfaces smaller and larger respectively, which confine, along with a cylinder, pressure chambers, wherein the smaller piston unit is driven electrically with an electric drive, and the cylinder, for applying an 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 larger 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 unit.
Dependencies are inferred from the claim text.