Danfoss Power Solutions Aps

Poul Ennemark

Tom Rudolph

Abdul Karim Rahimzai

Niels Bjarne Hansen

Nils E Sevelsted

Thomas Bauer

A hydraulic arrangement () including a supply port (P), a return port (T), a working port arrangement (L, R), and a valve () controlling a supply of hydraulic fluid from the supply port (P) to the working port arrangement (L, R), wherein the valve () includes a housing () and a spool () movable in lengthwise direction in the housing () and forming together with the housing () at least one flow path the resistance of which depends on the position of the spool () in the housing (), and the spool () is actuated by a hydraulic pilot pressure () in a pressure chamber (). In such a hydraulic arrangement a safety functionality should be achieved in a simple way. To this end the housing () includes a pilot pressure relief port () connected to the return port (T) via a shut-off valve () and the spool () after a predetermined stroke () opens a connection between the pressure chamber () and the pilot pressure relief port ().

Hydraulic arrangement

A fluid controller (), in particular as part of a hydraulic steering unit, is described, said controller () comprising a housing () having a supply port arrangement, a sleeve () arranged rotatably in a bore of the housing (), a spool () arranged rotatably in the sleeve (), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve () comprises a commutation geometry () having a number of pairs of commutation grooves () and controlling together with a housing geometry () of the housing () a flow of hydraulic fluid into and out of the working chambers and the spool () comprises a spool geometry controlling together with a valve geometry of the sleeve () a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behaviour. To this end at least one of the commutation grooves () comprise a closed bottom and at least one of the commutation grooves () comprise a throughgoing opening () forming part of the valve geometry.

Fluid controller, in particular as part of a hydraulic steering unit

A fluid controller (), in particular as part of a hydraulic steering unit, is described said controller () comprising a housing () having a supply port arrangement, a sleeve () arranged rotatably in a bore of the housing (), a spool () arranged rotatably in the sleeve (), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve () comprises a commutation geometry () having a first partition and controlling together with a housing geometry () of the housing () a flow of hydraulic fluid into and out of the working chambers and the spool () comprises a spool geometry () controlling together with a valve geometry () of the sleeve () a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behavior. To this end the valve geometry () comprises a second partition different from the first partition.

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Sønderborg, Denmark

Poul Ennemark