Hydraulic drive unit for e.g. core puller, has controller or regulation unit controlling regulation of pump, where signal of controller or regulation unit is measured, so that position of piston is computed from measured signal

摘要

The unit (1) has a hydraulic piston movable between two end positions (E1, E2) in a cylinder (2) for moving an injection molding machine part. A hydraulic passage (5) is arranged between a hydraulic pump (4) and the cylinder, where the hydraulic pump conveys the hydraulic fluid. A controller or a regulation unit (7) controls regulation of the hydraulic pump. A flow rate of the hydraulic fluid per unit time unit is measured by a measuring unit. Signal of the controller or regulation unit is measured, so that a position (P) of the piston is computed from the measured signal.