Danfoss Power Solutions Aps

Mogens Frederiksen

Niels Arbjerg

Poul Ennemark

Casper Mikael Olesen

Charles Anthony Bates

Bendt Porskrog

Niels Bjarne Hansen

Nils E Sevelsted

Helle Bonde Rasmussen

Paul Kiran

Per Bonde

The invention relates to a hydraulic steering unit () including a housing (), a spool, a sleeve () arranged between spool and housing (), and a measuring motor () having a number of working chambers (), wherein a first commutation geometry () and a second commutation geometry () are arranged between the sleeve () and the housing (), wherein the commutation geometries () are connected to the working chambers () of the measuring motor () and the housing includes a first direction port (), a second direction port (), a pressure port (), and a return port (). The object is to have a good steering behavior. To this end one of the commutation geometries () is directly connected to the first direction port ().

Hydraulic steering unit

A hydraulic steering unit includes a pressure port connected to a main flow path and a tank port connected to a tank flow path, and a working port arrangement having left and right working flow paths. A first bridge arrangement has first left and first right orifices connected to the main flow path and to first left or first right connecting points, respectively, each connecting point associated respectively with the left or right working flow paths, and second left and second right orifices connected to the tank flow path and to the first left or first right connecting points, respectively. A second bridge arrangement has a similar orifice arrangement connected to second left or second right connecting points. The first and second bridge arrangements have different steering characteristics. Selection means for connecting one of the bridge arrangements between the pressure port and the working port arrangement are provided.

A hydraulic steering unit includes a pressure port connected to a main flow path and a tank port connected to a tank flow path, left and right working ports connected to left and right working flow paths, respectively, a bridge arrangement of variable orifices having a first left orifice connected to the main flow path and to the left working flow path, a first right orifice connected to the main flow path and to the right working flow path, a second left orifice connected to the left working flow path and to the tank flow path, and a second right orifice connected to the right working flow path and to the tank flow path. A variable diagonal orifice is connected to the main flow path and to the tank flow path. The bridge arrangement orifices being closed in neutral position and the diagonal orifice being open in neutral position.

A hydraulic steering unit () is described, said hydraulic steering unit () comprising a supply port arrangement having a pressure port (P) connected to a main flow path () and a tank port (T) connected to a tank flow path (), a working port arrangement having a left working port (L) connected to a left working flow path () and a right working port (R) connected to a right working flow path (), a bridge arrangement () of variable orifices having a first left orifice (AL) connected to the main flow path () and to the left working flow path (), a first right orifice (AR) connected to the main flow path () and to the right working flow path (), a second left orifice (AL) connected to the left working flow path () and to the tank flow path (), and a second right orifice (AR) connected to the right working flow path () and to the tank flow path (). Such a hydraulic steering unit should be operated together with a pressure source of fixed displacements. To this end an idle flow path () branches off the main flow path (), wherein a variable idle orifice (An) is arranged in the idle flow path (), the idle orifice (An) being open in neutral position and closing out of neutral position.

A hydraulic steering unit () is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path () and a tank port (T) connected to a tank flow path (), a working port arrangement having a left working port connected to a left working flow path () and a right working port (R) connected to a right working flow path (), a bridge arrangement () of variable orifices (AL, AR, AL, AR) having a first left orifice (AL) connected to the main flow path () and to the left working flow path (), a first right orifice (AR) connected to the main flow path () and to the right working flow path (), a second left orifice (AL) connected to the left working flow path () and to the tank flow path (), and a second right orifice (AR) connected to the right working flow path () and to the tank flow path (). Such a steering unit should make steering comfortable. To this end a measuring motor () a measuring motor () is arranged in one of the left working flow path () and the right working flow path () and an amplification flow path () is connected to the one working flow path () downstream the measuring motor ().

A hydraulic steering unit () is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path () and a tank port (T) connected to a tank flow path (), a first working port arrangement having a first left working port (L) connected to a first left working flow path () and a first right working port (R) connected to a first right working flow path (), a variable first left orifice (AL) connected to the main flow path () and to the first left working flow path (), a variable first right orifice (AR) connected to the main flow path () and to the first right working flow path (), a variable second left orifice (AL) connected to the first left working flow path () and to the tank flow path (), a variable second right orifice (AR) connected to the first right working flow path () and to the tank flow path (), and a second working port arrangement having a second left working port () connected to a second left working flow path () and a second right working port (R) connected to a second right working flow path (), wherein the variable first left orifice (AL) is connected to the second left working flow path () and the variable first right orifice (AR) is connected to the second right working flow path ().

A hydraulic steering unit () is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path () and a tank port (T) connected to a tank flow path (), a working port arrangement having a left working port (L) connected to a left working flow path () and a right working port (R) connected to a right working flow path (), a bridge arrangement () of variable neutral open orifices, said bridge arrangement () comprising a first left orifice (AL) connected to a main flow path () and to the left working flow path (), a first right orifice (AR) connected to a main flow path () and to the right working flow path (), a second left orifice (AL) connected to the left working flow path () and to the tank flow path (), and a second right orifice (AR) connected to the right working flow path () and to the tank flow path (). Such a steering unit has a good steering behavior but can function as a closed-center solution. To this end a further variable orifice arrangement is arranged between the supply port (P) arrangement and the working port arrangement (T), which further orifice arrangement is closed in neutral position.

A hydraulic steering unit () is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path () and a tank port (T) connected to a tank flow path (), a working port arrangement having a left working port (L) connected to a left working flow path () and a right working port (R) connected to a right working flow path (), a bridge arrangement () of variable orifices (AL, AL, AR, AR) having a first left orifice (AL) connected to the main flow path () and to the left working flow path (), a first right orifice (AR) connected to the main flow path () and to the right working flow path (), a second left orifice (AL) connected to the left working flow path () and to the tank flow path (), and a second right orifice (AR) connected to the right working flow path () and to the tank flow path (). Such a steering unit allows steering a vehicle with low energy consumption. To this end a load sensing port (LS) is provided, the load sensing port (LS) signaling a pressure in the steering unit () to the outside.

A hydraulic steering unit () is described comprising a supply port arrangement having a pressure port () connected to a main flow path () and a tank port () connected to a tank flow path (), a working port arrangement having a left working port (L) connected to a left working flow path () and a right working port (R) connected to a right working flow path (), a variable first left orifice (AL) connected to the main flow path () and to the left working flow path (), a variable first right orifice (AR) connected to the main flow path () and to the right working flow path (), a variable second left orifice (AL) connected to the left working flow path () and to the tank flow path (), and a variable second right orifice (AR) connected to the right working flow path () and to the tank flow path (). Such a steering unit should allow comfortable steering. To this end a measuring motor () is arranged in one of the working flow parts ().

A hydraulic steering unit () is described comprising a supply port arrangement having a pressure port () connected to a main flow path () and a tank port (T) connected to a tank flow path (), a working port arrangement having a left working port (L) connected to a left working flow path () and a right working port (R) connected to a right working flow path (), a bridge arrangement () of variable orifices having a first left orifice (AL) connected to the main flow path () and to the left working flow path (), a first right orifice (AR) connected to the main flow path () and to the right working flow path (), a second left orifice (AL) connected to the left working flow path () and to the tank flow path (), and a second right orifice (AR) connected to the right working flow path () and to the tank flow path (). Such a hydraulic steering unit should allow comfortable steering. To this end a measuring motor arrangement is arranged in one of the left working flow path () and the right working flow path (), the measuring motor arrangement () having a first measuring motor () and a second measuring motor ().

A hydraulic steering unit () is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path () and a tank port (T) connected to a tank flow path (), a working port arrangement having a left working port (L) connected to a left working flow path () and a right working port (R) connected to a right working flow path (), a bridge arrangement () of variable orifices having a first left orifice (AL) connected to the main flow path () and to a left connecting point () at the left working flow path (), a first right orifice (AR) connected to the main flow path () and to a right connecting point () at the right working flow path (), a second left orifice (AL) connected to the left connecting point () at the left working flow path () and to the tank flow path (), and a second right orifice (AR) connected to the right connecting point () at the right working flow path () and to the tank flow path (). Such a steering unit should allow for a comfortable steering. To this end reverse flow prevention means () are arranged in at least one of the left working flow path () and the right working flow path ().

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 ().

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Sydals, Denmark

Mogens Frederiksen