Brueninghaus Hydromatik Gmbh

Bernhard Adler

Reinhold Schniederjan

Horst Stegmaier

The invention relates to an electromagnet for actuating a valve. To this end, the electromagnet () comprises an armature (), which can be axially displaced in an armature space () and whose axial motion displaces a tappet () to the valve. The electromagnet is provided with reflux channel (), which is connected to the armature space () and via which the armature space () is connected to a tank volume () in order to lead away a pressure medium leakage flow that is flowing out of the valve and into the armature space ().

Electromagnet

A pressure-control valve ( ) comprises a first control piston ( ), which is disposed between a first pressure chamber ( ), which adjoins the first control piston ( ) and is connected to at least one working line (A, B), and a second pressure chamber ( ), which adjoins the first control piston ( ) and is pushed against a stop ( ) by a first preloading spring ( ). A throttle ( ) connects the first pressure chamber ( ) and the second pressure chamber ( ). The second pressure chamber ( ) is connected to a second control piston ( ), which is preloaded by a second preloading spring ( ) and which, when a predetermined pressure in the second pressure chamber ( ) is exceeded, is displaced to an extent such that a control edge ( ) of the second control piston ( ) clears a connection of the second pressure chamber ( ) to a hydraulic fluid discharge point ( ). The first control piston ( ) comprises a control edge ( ) which connects an actuating pressure line ( ) to a hydraulic fluid discharge point ( ) when the first control piston ( ) is displaced against the first preloading spring ( ). An actuator ( ), which is regulated by a control signal, presses onto the second control piston ( ) against the second preloading spring ( ).

Pressure-control valve

A control circuit, in particular for a slewing gear of a digger, has a hydraulic fluid tank ( ), connected to two adjusting pressure chambers ( ). Each of the connections contains a separate brake valve ( ). The first of the valves ( ) is operated by the differential between the working pressure in the first working conduit ( ), and the control pressure in the control conduit ( ) charged with the higher pressure. The second valve ( ) is operated by the differential between the working pressure in the second working circuit ( ) and the control pressure in the control circuit charged with the higher pressure. Slow braking by the brake valves is interrupted when the slewing gear swings out against a resistance such as a heap of debris.

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Elchingen, Germany

Bernhard Adler