Danfoss Power Solutions Aps

Danfoss A/s

Sauer Danfoss Aps

Niels Arbjerg

Mogens Frederiksen

Poul Ennemark

Casper Mikael Olesen

Charles Anthony Bates

Abdul Karim Rahimzai

Rene Andersen

Bendt Porskrog

Ole Soerensen

Holger Krogsg&aring;rd Rom

Jesper Kirkegaard

Paul Kiran

Steffen Lorentzen

René Andersen

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 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 ().

Hydraulic steering arrangement

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 device is provided comprising a supply port arrangement having a pressure port (P) and a tank port (), a working port arrangement having two working ports (L, R), a main flow path () between the pressure port (P) and the working port arrangement, a return flow path () between the working port arrangement and the tank port (), flow meter means () being arranged in said main flow path (), an amplification flow path () being 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 pressure port (P) to said working port arrangement. A risk of dangerous situations in case of jamming of the flow meter should be reduced. To this end pressure increasing means are provided increasing a pressure over said flow meter means () in case a flow through said main flow path () is blocked by said flow meter ().

Hydraulic steering device

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.

A control device () for a hydrostatic steering motor comprises supply and return pump and tank connections (P, T), a slide valve arrangement in which inner and outer slide element sleeves are rotatable relative to each other to both sides of a neutral position through a limited small angle, said sleeves mutually forming controlled supply and return passages connected to said motor having supply and return throttles which are closed when said sleeves are in a neutral position, bypass throttle means () between said pump and tank connections (P, T) being open when said sleeves are in a neutral position, said bypass throttle means () having a set of at least two variable orifices connected in series. In such a device the noise should be reduced when a higher supply pressure of hydraulic fluid is used.

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Sydals, Denmark

Niels Arbjerg