LOAD-DEPENDENT REGULATION OF HYDRAULIC MOTORS

摘要

Method for the load-dependent regulation of a hydrostatic drive (1), with a closed hydraulic fluid circuit comprising a first hydraulic motor (5) and, parallel to this, a second hydraulic motor (6), whereby both hydraulic motors (5 and 6) are capable of being powered by a hydraulic pump (3) via a high-pressure line (7) and a low-pressure line (8) and are mechanically coupled to each other via a transmission (70). The displacement of the first hydraulic motor (5) can be adjusted proportionally to an electrical signal of an electronic control system (50) by means of an electro-proportional control valve (10) and the displacement of the second hydraulic motor (6) can be adjusted by means of a pressure-proportional control valve (20) which is hydraulically connected to the high-pressure line (7) via a control pressure line (21). 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 (20) dependent on the high pressure, proportional to the exceedance of a predefinable pressure limit in the high-pressure line (7), the displacement of the second hydraulic motor (6) is adjusted by means of a second servo control unit which can be controlled via the pressure-proportional control valve (20). By means of the electronic control system (50), the actual volume flow passing through the first hydraulic motor (5) 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 (50) calculates an adapted control signal and transmits this to the electro-proportional control valve (10), as a result of which the displacement of the first hydraulic motor (5) is adaptable by means of a first servo control unit (14), which is controlled via the electro-proportional control valve (10).

主权项

1. A 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 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, whereby:
the displacement of the first hydraulic motor can be adjusted proportionally to an electrical signal of an electronic control system via an electro-proportional control valve, the displacement of the second hydraulic motor can be adjusted via a pressure-proportional control valve which is hydraulically connected to the high-pressure line via a control pressure line and which can be activated by means of a control pressure dependent on the high pressure;whereby the method comprises the following steps:
automatic high-pressure-dependent opening of the pressure-proportional control valve, proportional to an exceedance of a predefinable pressure limit in the high-pressure line, whereby the predefinable pressure limit is equal to an opening pressure of the pressure-proportional control valve, adjustment of the displacement of the second hydraulic motor by a second servo control unit which can be controlled via the pressure-proportional control valve, definition of an actual volume flow passing through the first hydraulic motor by means of the electronic control system, comparison of the actual value for the volume flow with a target value for the volume flow by means of the electronic control system, calculation of an adapted control signal by the electronic control system based on a deviation between the actual and target value for the volume flow, transmitting of the adapted control signal to the electro-proportional regulation valve, and electro-proportional adaptation of the displacement of the first hydraulic motor by means of a first servo control unit which can be controlled via the electro-proportional control valve.