Load-dependent regulation of hydraulic motors

Abstract

Method for the load-dependent regulation of a hydrostatic drive (), with a closed hydraulic fluid circuit comprising a first hydraulic motor () and, parallel to this, a second hydraulic motor (), whereby both hydraulic motors (and) are capable of being powered by a hydraulic pump () via a high-pressure line () and a low-pressure line () and are mechanically coupled to each other via a transmission (). The displacement of the first hydraulic motor () can be adjusted proportionally to an electrical signal of an electronic control system () by means of an electro-proportional control valve () and the displacement of the second hydraulic motor () can be adjusted by means of a pressure-proportional control valve () which is hydraulically connected to the high-pressure line () via a control pressure line (). The pressure-proportional control valve can be activated by means of a control pressure which is dependent on the high pressure. By means of automatic opening of the pressure-proportional control valve () dependent on the high pressure, proportional to the exceedance of a predefinable pressure limit in the high-pressure line (), the displacement of the second hydraulic motor () is adjusted by means of a second servo control unit which can be controlled via the pressure-proportional control valve (). By means of the electronic control system (), the actual volume flow passing through the first hydraulic motor () is determined and compared with a target value for the volume flow. Based on a deviation between the actual and target value for the volume flow, the electronic control system () calculates an adapted control signal and transmits this to the electro-proportional control valve (), as a result of which the displacement of the first hydraulic motor () is adaptable by means of a first servo control unit (), which is controlled via the electro-proportional control valve ().