Danfoss Power Solutions Aps

Sauer Danfoss Aps

Sauer-danfoss Holding A/s

Sauer-danfoss (nordborg) A/s

Minibooster Hydraulics A/s

Poul Ennemark

Niels Arbjerg

Mogens Frederiksen

Casper Mikael Olesen

Charles Anthony Bates

Tom Rudolph

Tom Tychsen

Svend Erik Thomsen

Jens Vester

Soeren Liljenberg

Siegfried Zenker

Niels Bjarne Hansen

Anders Kryhlmand

Leif Hansen

Morten Hoeck Petersen

Christen Espersen

Knud Meldgaard Jensen

Peter Gade Peistrup

Ove Pedersen

Brian Petersen

Joergen Mads Clausen

Joergen P Todsen

S&oslash;ren Zaremba

Thomas Bauer

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 () 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 steering system () is provided having a steering device () and a symmetrically acting steering motor (), said steering device () comprising a supply port arrangement having a high pressure port (P) and a low pressure port (T), a working port arrangement having two working ports (L, R), a control valve (), two working lines () each connecting said control valve () with one of said working ports (L, R), and a measuring motor (). Such a hydraulic steering system should show a comfortable steering behavior. To this end said measuring motor () is arranged in one of said working lines ().

Hydraulic steering system

A hydraulic steering system () is described comprising a first steering circuit () and a second steering circuit (), each of said steering circuits () comprising a steering device () and a steering motor () connected to said steering device (), each of said steering devices () comprising a supply port arrangement having a high pressure port (Pa, Pb) and a low pressure port (Ta, Tb), a working port arrangement having two working ports (La, Ra; Lb, Rb) connected to said steering motor (), a control valve (), and a measuring motor (). Such a steering system should have a comfortable steering behavior. To this end in each of said steering devices () said measuring motor () is arranged in a working line () between said control valve () and one of said working ports (La, Ra; Lb, Rb).

A method for controlling steering of a vehicle () is provided, the vehicle () defining two or more steerable axes, and the vehicle () comprising a number of wheels (), each of said wheels () being associated with one of said steerable axes in such a manner that steering of a given wheel () is obtained by steering the steerable axis associated therewith. The method comprises providing a first, a second and a third steering input. The first steering input defines a point of intersection between a virtual steering axis () and a longitudinal center axis defined by the vehicle (). The second steering input defines an angle between the virtual steering axis () and the longitudinal center axis. The third steering input defines a position of a center of rotation () along the virtual steering axis (). A position for each of the steerable axes defined by the vehicle () is calculated, which causes the vehicle () to rotate about the center of rotation () defined by the first, second and third steering inputs, and each of the steerable axes is moved to the calculated position.

Method for controlling steering of a vehicle

A hydraulic system () is provided comprising a supply port arrangement (P, T), a working port arrangement (A, B), and a booster section (), said supply port arrangement having at least a supply port (P), said booster section () being arranged between said supply port arrangement (P, T) and said working port arrangement (A, B). The operational possibilities of such a hydraulic system should be extended. To this end said working port arrangement comprises at least two working ports (A, B), flow direction changing means () are provided changing a flow direction through said working port arrangement and inactivating means () are provided inactivating or activating said booster section () for each flow direction.

Hydraulic system

A hydraulic steering device () is described comprising a supply port arrangement having a supply port (P) and a tank port (T), a working port arrangement having two working ports (L, R), a main flow path () between the supply port (P) and the working port arrangement, a return flow path () between the working port arrangement and the tank port (T), flow meter means () being arranged in said main flow path (), said flow meter means () comprising at least two flow meters () and a flow meter valve means (), said flow meter valve means () in a first operation mode connecting at least two flow meters () in parallel and in a second operation mode making inactive at least one flow meter (). Such a steering device should be operated comfortable for a driver. To this end an amplification flow path () is arranged in parallel to said main flow path (), said amplification flow path () being connected to said main flow path () downstream said flow meter means () in a direction from said supply port (P) to said working port arrangement.

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Soenderborg, Denmark

Poul Ennemark