| 摘要 |
A hydraulic control arrangement (10) for regulating the position and/or pull of a plough coupled to a farm tractor via a lifting gear is proposed in which a regulating valve (11) is hydraulically activated via two full bridges (46, 47) lying downstream from a mixing valve (48). Allocated to the control spool (41) of the regulating valve (11) are two outer servo pistons (73, 73'), activated by the position-regulating circuit (46), and two inner servo pistons (78, 78'), activated by the pull-regulating circuit (47), of which the former (73, 73') have a larger, effective pressure area and can be uncoupled from the latter (78, 78') by the maximum control-spool stroke (88). Thus conflicting requirements can be fulfilled in a simple manner by the control arrangement working through high dynamics with optimum time response during pull control and with optimum stability and high adjusting accuracy during position control as a result of suitable damping. <IMAGE>
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