Danfoss Power Solutions Aps

Nils E Sevelsted

Bendt Porskrog

Morten Hoeck Petersen

Helle Bonde Rasmussen

Mogens Frederiksen

Abdul Karim Rahimzai

Niels Bjarne Hansen

Poul Ennemark

Ylnghui Liu

Per Bonde

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 hydraulic steering unit is described comprising a housing () and a non-return valve () having a ball () and a valve seat () at an end of a channel () in the housing (), wherein a movement of the ball () away from the valve seat () is limited by an abutment () in the channel (). Such a steering unit should have a non-return valve which can be produced with low costs. To this end the abutment () extends transversely through the channel.

Hydraulic steering unit

A hydraulic overpressure valve () is provided comprising a valve housing (), a valve seat () located in said valve housing and having a seat center and a seat center axis (), a cone element () movable relatively to said valve seat (), said cone element () having a cone () protruding at least partly into said valve seat () and having a cone center axis (), and force generating means acting on said cone element () in a direction towards said valve seat (). Such a hydraulic overpressure valve should be operated with low noise. To this end said cone () is movable along a path of movement in which said cone center axis is kept outside said seat center axis ().

Hydraulic overpressure valve and hydraulic machine

A hydraulic steering device is provided comprising a supply port arrangement having a supply port (P) and a return port (T), a working port arrangement having two working ports (L, R), direction valve means () arranged between said supply port arrangement and said working port arrangement, at least two fluid meters (), each of said fluid meters () having a movable metering element (), said metering elements () being connected by a shaft (), said shaft () having an axis, selector valve means () being provided, said selector valve means () in a first position arranging said fluid meters () hydraulically in parallel and in a second position shutting off one of said fluid meters (), said selector valve means () having a valve element () shiftable in an direction parallel to said axis. It is an object to reduce wear in said hydraulic steering device in a simple manner. To this end said selector valve means () are arranged between said two fluid meters (), said shaft () extending through said valve element ().

Hydraulic steering device

A hydraulic control arrangement () is described having a directional valve (), a metering pump unit which has at least two metering pumps () which are connected hydraulically in parallel and are operable mechanically in parallel, and a shut-off valve () in hydraulic connection between two of the at least two metering pumps (), a pump connection (P) and a tank connection (T) which are connected to said metering pump unit by way of the directional valve (), and two working connections (L, R) connected to the directional valve (), a control input () of the shut-off valve () being connected to the pump connection (P) by means of a control valve. Such a control arrangement should be operated at a high hydraulic pressure and at the same time it should be made sure that the shut-off valve is actuated only when the required high pressure is available. To this end the control valve () is a pilot operated valve, an inlet () of said control valve () being connected to the pump connection (P), said control valve () connecting said input () and said pump connection (P) in an actuated state of said control valve ().

Growing community of inventors

Sønderborg, Denmark

Nils E Sevelsted