Patent ID: 7028599
Filing Date: 2006-04-18
Classification: F15B

Abstract:
1. A control device for continuous motion of a hydraulic control motor, comprising: a throttle needle; two throttle devices arranged in series in a hydraulic flow path between a pump and a tank; a hydraulic line branching off between the throttle devices, the hydraulic line arranged to lead to a working chamber of the control motor; wherein a first one of the throttle devices includes a controllable throttle valve having a piston in a housing bore, one side of the piston arranged to support a valve head forming a boundary of an annular gap between an inflow duct and an outflow duct, the throttle needle arranged on another side of the piston arranged in a hydraulic control path, the throttle needle axially movable in a throttle opening and configured to continuously control a pressure drop at the annular gap, the hydraulic control path extending from the inflow duct through the throttle opening to the tank, through a precontrol bore in the piston and through a pressure chamber arranged between the piston and the throttle opening, one end of the precontrol bore positioned on a side of the piston bordering the annular gap in a region of the inflow duct so that the one end of the precontrol bore remains open if the annular gap is closed, another end of the precontrol bore arranged so that the piston, in response to complete opening of the controllable throttle valve, pushes against a stop face to automatically close the another end of the precontrol bore; and wherein the control device is configured to operate according to an open-center principle.