Hydrostatic drive, especially for excavators

摘要

The drive consists of a hydraulic pump and motor, with at least the pump having a displacement which can be adjusted by valve actuated equipment. The valve is controlled by a signal which can be disabled, and a device can apply a further control signal, which is derived from the pressure in the hydraulic circuit between the pump and the motor. The device, and with it the valve actuation, so controls the displacement volume of the pump, that above a predetermined working pressure, the volume increases with decreasing pressure under positive load along a characteristic line (KLL) with negative gradient, and when under negative load decreases with decreasing pressure along a line (KLS) also having a negative gradient. The relationship holds in each quadrant of the 4-quadrant performance graph.