| 摘要 |
A servo-regulating circuit for a hydraulic forward drive unit (10), which operates with an electrically-controlled set value of the position and with mechanical feed-back of the actual position. The flows of the working medium to and from the drive unit (10), whose value determines the speed v of the tool movements, are fed via valve elements (34, 36) of a servo-regulating valve (29) which can be jointly controlled via the regulating distances epsilon 1 and epsilon 2 according to the pre-set value. The circuit amplification Kv can be switched by valve-controlled operation of a switching system. In the servo-regulating circuit, the servo-regulating valve (29) has at least one additional valve element (35, 37) which effects the positioning movements of the valve element serving to control the movement with the circuit amplification Kv1; through this element runs a flow-path, parallel to the flow-path of the servo-regulating valve (29), which can be opened up by the operation of an amplification control valve arrangement (51, 53); as a result the circuit amplification Kv2 is adjusted. A device (66) is provided with which the control-valve system can be controlled as required as regards its throughflow setting, which enables operation with the modified value, Kv2. |
