Danfoss Power Solutions Aps

Abdul Karim Rahimzai

Casper Mikael Olesen

Bendt Porskrog

Niels Arbjerg

Ole Soerensen

Poul Ennemark

Nils E Sevelsted

Rene Andersen

René Andersen

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 arrangement () including a supply port (), a return port (), a working port arrangement having two working ports (), a main flow path () between the supply port () and one of the working ports () and a return flow path () between the other working port () and the return port (), wherein the main flow path () includes a main orifice (A1), a flow meter (), a first flow meter orifice (A2) upstream the flow meter (), a second flow meter orifice (A3) downstream the flow meter (), and a first working port orifice (A4), the return flow path () includes a second working port orifice (A5), a load sensing point () is arranged between the main orifice (A1) and the first flow meter orifice (A2), a drain orifice (Ad) is arranged between the load sensing point () and the return port (), and a priority valve arrangement () is arranged between the supply port () and the main orifice (A1). Such a steering arrangement should enable a high steering speed without loss of comfort. To this end a load sensing port () of the priority valve arrangement () is connected to the load sensing point (), characterized in that a priority outlet (CF) of the priority valve arrangement () is directly connected to the main orifice (A1), the load sensing port () of the priority valve arrangement () is directly connected to the load sensing point () and the main flow path () includes a check valve () between the load sensing point () and the working port () of the main flow path (), the check valve () opening in a direction towards the working port ().

Hydraulic steering 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 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.

A hydraulic steering arrangementis described comprising a supply port arrangement having a pressure port () and a tank port (), a working port arrangement having two working ports (), a steering unit () arranged in a flow path () between the supply port arrangement () and the working port arrangement (), and a second flow path () in form of an amplification flow path bridging the steering unit () and having an amplification orifice (A) which is controlled as function of the steering unit (). Such a steering arrangement should have a possibility to change the steering behaviour. To this end at least a third flow path () in form of an amplification flow path is arranged in parallel to the second flow path (), wherein the second/or the third flow path () comprise an valve ().

A hydraulic steering arrangement () is described comprising a supply port arrangement (P, T) having a pressure port (P) and a tank port (T), a working port arrangement having two working ports (L, R), a main flow path () having a main orifice (A), at least one further orifice (A, A, A) downstream the main orifice (A), and a measuring motor (), the main flow path () being arranged between the pressure port (P) and the working port arrangement (L, R), a return flow path () arranged between the working port arrangement (L, R) and the tank port (T), an amplification flow path () having an amplification orifice (A) and being arranged between the pressure port (P) and the working port arrangement (L, R), and an adjustable pressure source () connected to the pressure port (P) and having a load sensing port (), wherein a main drain orifice (A) is connected between the main flow path () downstream the main orifice (A) and the return flow path (). It should be possible to operate such a steering arrangement with a dynamic flow. To this end a flow divider () connects the load sensing port () with the main flow path () downstream the main orifice (A) and the amplification flow path () downstream the amplification orifice (A).

A hydraulic steering arrangement is shown having a steering unit and two working ports each of which being connected to the steering unit by a working line (), wherein an anti jerk valve () is arranged in each working line (), the anti jerk valve () having a valve element () being loaded in opening direction by the pressure in the working line () and in closing direction by restoring means (). A vehicle equipped with such a steering arrangement should have a good comfort. To this end the valve element () is loaded in closing direction by the pressure in the working line () via delay means ().

A hydraulic steering arrangement () is described having a main flow path () with a flow meter () and an amplification flow path () opening into the main flow path () at a connecting point () located between the flow meter () and a working port arrangement (L, R). Such a steering arrangement should have in a simple way a large flow of the hydraulic fluid to the working port arrangement. To this end pressure increasing means () are arranged in the main flow path () upstream the connecting point ().

A hydraulic steering unit () is disclosed comprising a working port arrangement (L, R) having two working ports (L, R), a supply port arrangement having a high pressure port (P) and a low pressure port (T), a main flow path () having a main bleed (A) and a metering device () and being arranged between said high pressure port (P) and said working port arrangement (L, R), an amplification flow path () having an amplification bleed (Au) and being arranged between said high pressure port (P) and said working port arrangement (L, R), said main bleed (A) and said amplification bleed (Au) being controlled together by means of a steering handle () and being closed in neutral position of said steering handle (), and a drain bleed (Ad) which is open in neutral position of said steering handle (), said drain bleed (Ad) connecting a point () upstream said main bleed (A) and said amplification bleed (Au) to said low pressure port (T).

Hydraulic steering unit and hydraulic steering system

A hydraulic steering systemis described comprising a steering unit and a priority valve, said steering unit comprising a working port arrangement having two working ports, a supply port arrangement having a high pressure port and a low pressure port, a load sensing port, a main flow path having a main bleed and a metering device and being arranged between said high pressure port and said working port arrangement, an amplification flow path having an amplification bleed and being arranged between said high pressure port and said working port arrangement, said main bleed and said amplification bleed being controlled together by means of a steering handle and being closed in neutral position of said steering handle, wherein said priority valve comprises a priority outlet connected to said high pressure port of said steering unit, a valve element moveable in a priority direction to connect an inlet of said priority valve to said priority outlet, and a load sensing connection connected to said load sensing port of said steering unit, said priority outlet being connected to said load sensing connection via a priority valve bleed, a pressure at a point downstream said priority bleed acting on said valve element in said priority direction, wherein said load sensing port is connected to said low pressure port via a drain bleed being open in neutral position of said steering handle and closing upon actuation of said steering handle out of said neutral position.

Hydraulic steering system

A hydraulic steering system () is described comprising a steering unit () and a pressure source (), said steering unit () comprising a working port arrangement (L, R) having two working ports, a supply port arrangement having a high pressure port (P) and a low pressure port (), a main flow path () having a main bleed (A) and a metering device () and being arranged between said high pressure port (P) and said working port arrangement (L, R), an amplification flow path () having an amplification bleed (Au) and being arranged between said high pressure port (P) and said working port arrangement (L, R), said main bleed (A) and said amplification bleed (Au) being controlled together by means of a steering handle () and being closed in neutral position of said steering handle, and said pressure source () having a variable displacement.

A hydraulic steering arrangement () is provided comprising a static steering unit () and an adjustable pressure source () connected to a pressure port () of said steering unit () and having a load sensing port (). Such a steering unit should enable a fast reaction of the steering unit. To this end said pressure source () is a dynamic pressure source having an orifice (Adyn) outputting hydraulic fluid to said load sensing port (), a load sensing line () connecting said load sensing port () and a low pressure port (), a control valve () being arranged in said load sensing line () between said load sensing port () and said low pressure port (), said control valve () being actuated by a control pressure within said steering unit () and throttling a flow through said load sensing line () depending on said control pressure.

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Sonderborg, Denmark

Abdul Karim Rahimzai