A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (8) connected to a main flow path (2) and a tank port (5) connected to a tank flow path (3), a working port arrangement having a left working port (L) connected to a left working flow path (4) and a right working port (R) connected to a right working flow path (5), a variable first left orifice (A2L) connected to the main flow path (2) and to the left working flow path (4), a variable first right orifice (A2R) connected to the main flow path (2) and to the right working flow path (5), a variable second left orifice (A3L) connected to the left working flow path (4) and to the tank flow path (3), and a variable second right orifice (A3R) connected to the right working flow path (5) and to the tank flow path (3). Such a steering unit should allow comfortable steering. To this end a measuring motor (15) is arranged in one of the working flow parts (4, 5).

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a first working port arrangement having a first left working port (L1) connected to a first left working flow path (4) and a first right working port (R1) connected to a first right working flow path (5), a variable first left orifice (A2L) connected to the main flow path (2) and to the first left working flow path (4), a variable first right orifice (A2R) connected to the main flow path (2) and to the first right working flow path (5), a variable second left orifice (A3L) connected to the first left working flow path (4) and to the tank flow path (3), a variable second right orifice (A3R) connected to the first right working flow path (5) and to the tank flow path (3), and a second working port arrangement having a second left working port (12) connected to a second left working flow path (9) and a second right working port (R2) connected to a second right working flow path (10), wherein the variable first left orifice (A2L) is connected to the second left working flow path (9) and the variable first right orifice (A2R) is connected to the second right working flow path (10).

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a first working port arrangement having a first left working port (L1) connected to a first left working flow path (4) and a first right working port (R1) connected to a first right working flow path (5), a variable first left orifice (A2L) connected to the main flow path (2) and to the first left working flow path (4), a variable first right orifice (A2R) connected to the main flow path (2) and to the first right working flow path (5), a variable second left orifice (A3L) connected to the first left working flow path (4) and to the tank flow path (3), a variable second right orifice (A3R) connected to the first right working flow path (5) and to the tank flow path (3), and a second working port arrangement having a second left working port (12) connected to a second left working flow path (9) and a second right working port (R2) connected to a second right working flow path (10), wherein the variable first left orifice (A2L) is connected to the second left working flow path (9) and the variable first right orifice (A2R) is connected to the second right working flow path (10).

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a working port arrangement having a left working port (L) connected to a left working flow path (4) and a right working port (R) connected to a right working flow path (5), a bridge arrangement (21) of variable orifices (A2L, A3L, A2R, A3R) having a first left orifice (A2L) connected to the main flow path (2) and to the left working flow path (4), a first right orifice (A3R) connected to the main flow path (2) and to the right working flow path (5), a second left orifice (A3L) connected to the left working flow path (4) and to the tank flow path (3), and a second right orifice (A3R) connected to the right working flow path (5) and to the tank flow path (3). 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 (1) to the outside.

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a working port arrangement having a left working port (L) connected to a left working flow path (4) and a right working port (R) connected to a right working flow path (5), a bridge arrangement (21) of variable orifices (A2L, A3L, A2R, A3R) having a first left orifice (A2L) connected to the main flow path (2) and to the left working flow path (4), a first right orifice (A3R) connected to the main flow path (2) and to the right working flow path (5), a second left orifice (A3L) connected to the left working flow path (4) and to the tank flow path (3), and a second right orifice (A3R) connected to the right working flow path (5) and to the tank flow path (3). 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 (1) to the outside.

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a working port arrangement having a left working port (L) connected to a left working flow path (9) and a right working port (R) connected to a right working flow path (10), a bridge arrangement (15) of variable orifices having a first left orifice (A2L) connected to the main flow path (2) and to a left connecting point (16) at the left working flow path (9), a first right orifice (A2R) connected to the main flow path (2) and to a right connecting point (17) at the right working flow path (10), a second left orifice (A3L) connected to the left connecting point (16) at the left working flow path (9) and to the tank flow path (3), and a second right orifice (A3R) connected to the right connecting point (17) at the right working flow path (10) and to the tank flow path (3). Such a steering unit should allow for a comfortable steering. To this end reverse flow prevention means (20, 21) are arranged in at least one of the left working flow path (9) and the right working flow path (10).

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (2) and a tank port (T) connected to a tank flow path (3), a working port arrangement having a left working port (L) connected to a left working flow path (9) and a right working port (R) connected to a right working flow path (10), a bridge arrangement (15) of variable orifices having a first left orifice (A2L) connected to the main flow path (2) and to a left connecting point (16) at the left working flow path (9), a first right orifice (A2R) connected to the main flow path (2) and to a right connecting point (17) at the right working flow path (10), a second left orifice (A3L) connected to the left connecting point (16) at the left working flow path (9) and to the tank flow path (3), and a second right orifice (A3R) connected to the right connecting point (17) at the right working flow path (10) and to the tank flow path (3). Such a steering unit should allow for a comfortable steering. To this end reverse flow prevention means (20, 21) are arranged in at least one of the left working flow path (9) and the right working flow path (10).

A hydraulic steering unit (1) is described, said hydraulic steering unit (1) comprising a supply port arrangement having a pressure port (P) connected to a main flow path (3) and a tank port (T) connected to a tank flow path (4), a working port arrangement having a left working port (L) connected to a left working flow path (5) and a right working port (R) connected to a right working flow path (6), a bridge arrangement (14) of variable orifices having a first left orifice (A2L) connected to the main flow path (3) and to the left working flow path (5), a first right orifice (A2R) connected to the main flow path (3) and to the right working flow path (6), a second left orifice (A3L) connected to the left working flow path (5) and to the tank flow path (4), and a second right orifice (A3R) connected to the right working flow path (6) and to the tank flow path (4). Such a hydraulic steering unit should be operated together with a pressure source of fixed displacements. To this end an idle flow path (15) branches off the main flow path (3), wherein a variable idle orifice (An) is arranged in the idle flow path (15), the idle orifice (An) being open in neutral position and closing out of neutral position.

A hydraulic steering unit (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (5) and a tank port (T) connected to a tank flow path (6), a working port arrangement having a left working port (L) connected to a left working flow path (7) and a right working port (R) connected to a right working flow path (8), a bridge arrangement (14) of variable neutral open orifices, said bridge arrangement (14) comprising a first left orifice (A2L) connected to a main flow path (5) and to the left working flow path (7), a first right orifice (A2R) connected to a main flow path (5) and to the right working flow path (8), a second left orifice (A3L) connected to the left working flow path (7) and to the tank flow path (6), and a second right orifice (A3R) connected to the right working flow path (8) and to the tank flow path (6). 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 (1) is described comprising a supply port arrangement having a pressure port (P) connected to a main flow path (5) and a tank port (T) connected to a tank flow path (6), a working port arrangement having a left working port (L) connected to a left working flow path (7) and a right working port (R) connected to a right working flow path (8), a bridge arrangement (14) of variable neutral open orifices, said bridge arrangement (14) comprising a first left orifice (A2L) connected to a main flow path (5) and to the left working flow path (7), a first right orifice (A2R) connected to a main flow path (5) and to the right working flow path (8), a second left orifice (A3L) connected to the left working flow path (7) and to the tank flow path (6), and a second right orifice (A3R) connected to the right working flow path (8) and to the tank flow path (6). 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.