Abstract: A hydraulic steering unit (2) includes a steering unit (2) including a supply port arrangement having a supply port (P) and a return port (T), a working port arrangement having two working ports (LR), a steering valve arrangement having two valve elements (32, 33) arranged in a housing (30, 38, 39) and being moveable in relation to each other to change characteristics of orifices, and a measuring motor (9) arranged in a line between the steering valve arrangement and one of the working ports (LR). A hydraulic steering unit should create similar end stop sealings in both steering directions. To this end, backpressure means are provided generating a backpressure on the measuring motor (9), wherein the backpressure means are controlled by the valve element (32, 33), and friction means (43, 43?) are provided between one of the valve elements (33) and the housing (30, 38, 39) or a rotating part of the measuring motor (9) and the housing (30, 38, 39), respectively.

Abstract: A hydraulic overpressure valve (1) is provided comprising a valve housing (2), a valve seat (3) located in said valve housing and having a seat center and a seat center axis (4), a cone element (5) movable relatively to said valve seat (3), said cone element (5) having a cone (6) protruding at least partly into said valve seat (3) and having a cone center axis (4), and force generating means acting on said cone element (5) in a direction towards said valve seat (3). Such a hydraulic overpressure valve should be operated with low noise. To this end said cone (6) is movable along a path of movement in which said cone center axis is kept outside said seat center axis (4).

Abstract: A hydraulic steering unit (3) 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 (7) having a main bleed (A1) and a metering device (8) and being arranged between said high pressure port (P) and said working port arrangement (L, R), an amplification flow path (9) having an amplification bleed (Au) and being arranged between said high pressure port (P) and said working port arrangement (L, R), said main bleed (A1) and said amplification bleed (Au) being controlled together by means of a steering handle (6) and being closed in neutral position of said steering handle (6), and a drain bleed (Ad) which is open in neutral position of said steering handle (6), said drain bleed (Ad) connecting a point (11) upstream said main bleed (A1) and said amplification bleed (Au) to said low pressure port (T).

Abstract: A hydraulic steering system 1 is 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

Abstract: A hydraulic steering system (1) is described comprising a steering unit (3) and a pressure source (4), said steering unit (3) 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 (5), a main flow path (7) having a main bleed (A1) and a metering device (8) and being arranged between said high pressure port (P) and said working port arrangement (L, R), an amplification flow path (9) having an amplification bleed (Au) and being arranged between said high pressure port (P) and said working port arrangement (L, R), said main bleed (A1) and said amplification bleed (Au) being controlled together by means of a steering handle (6) and being closed in neutral position of said steering handle, and said pressure source (4) having a variable displacement.

Abstract: A hydraulic overpressure valve (1) is provided comprising a valve housing (2), a valve seat (3) located in said valve housing and having a seat center and a seat center axis (4), a cone element (5) movable relatively to said valve seat (3), said cone element (5) having a cone (6) protruding at least partly into said valve seat (3) and having a cone center axis (4), and force generating means acting on said cone element (5) in a direction towards said valve seat (3). Such a hydraulic overpressure valve should be operated with low noise. To this end said cone (6) is movable along a path of movement in which said cone center axis is kept outside said seat center axis (4).

Abstract: A hydraulic steering system 1 is 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

Abstract: A hydraulic steering system (1) is described comprising a steering unit (3) and a pressure source (4), said steering unit (3) 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 (5), a main flow path (7) having a main bleed (A1) and a metering device (8) and being arranged between said high pressure port (P) and said working port arrangement (L, R), an amplification flow path (9) having an amplification bleed (Au) and being arranged between said high pressure port (P) and said working port arrangement (L, R), said main bleed (A1) and said amplification bleed (Au) being controlled together by means of a steering handle (6) and being closed in neutral position of said steering handle, and said pressure source (4) having a variable displacement.

Abstract: A hydraulic steering unit (3) 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 (7) having a main bleed (A1) and a metering device (8) and being arranged between said high pressure port (P) and said working port arrangement (L, R), an amplification flow path (9) having an amplification bleed (Au) and being arranged between said high pressure port (P) and said working port arrangement (L, R), said main bleed (A1) and said amplification bleed (Au) being controlled together by means of a steering handle (6) and being closed in neutral position of said steering handle (6), and a drain bleed (Ad) which is open in neutral position of said steering handle (6), said drain bleed (Ad) connecting a point (12) upstream said main bleed (A1) and said amplification bleed (Au) to said low pressure port (T).

Abstract: A hydraulic control arrangement (1) is described having a directional valve (2), a metering pump unit which has at least two metering pumps (3, 4) which are connected hydraulically in parallel and are operable mechanically in parallel, and a shut-off valve (6) in hydraulic connection between two of the at least two metering pumps (3, 4), a pump connection (P) and a tank connection (T) which are connected to said metering pump unit by way of the directional valve (2), and two working connections (L, R) connected to the directional valve (2), a control input (8) of the shut-off valve (6) being connected to the pump connection (P) by means of a control valve. Such a control arrangement should be operated at a high hydraulic pressure and at the same time it should be made sure that the shut-off valve is actuated only when the required high pressure is available.

Abstract: A hydraulic control arrangement (1) is described having a directional valve (2), a metering pump unit which has at least two metering pumps (3, 4) which are connected hydraulically in parallel and are operable mechanically in parallel, and a shut-off valve (6) in hydraulic connection between two of the at least two metering pumps (3, 4), a pump connection (P) and a tank connection (T) which are connected to said metering pump unit by way of the directional valve (2), and two working connections (L, R) connected to the directional valve (2), a control input (8) of the shut-off valve (6) being connected to the pump connection (P) by means of a control valve. Such a control arrangement should be operated at a high hydraulic pressure and at the same time it should be made sure that the shut-off valve is actuated only when the required high pressure is available.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavored to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavoured to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: The invention concerns a hydraulic steering (1) with a supply connection arrangement (P, T), a steering motor (2) and a steering unit (3) between the supply connection arrangement and the steering motor (2), the steering unit (3) having a directional section (4) and a measuring section (5), a steering valve (9) being arranged in parallel to the steering unit (3). With such a steering, it is endeavored to achieve the best possible safety. For this purpose, it is ensured that for each steering direction the directional section (4) comprises a first outlet (A1L, A1R), which is connected to the steering motor (2) by means of a first pipe (23, 24), and a second outlet (A2L, A2R), which is connected to the steering motor (2) by means of a second pipe (25, 26), the first outlet (A1L, A1R) being, in the neutral position of the directional section (4), connected to the measuring section (5), and the first pipe (23, 24) being interruptible by means of a valve arrangement (27, 27a).

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavoured to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavoured to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavored to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: The invention concerns a hydraulic steering (1) with a supply connection arrangement (P, T), a steering motor (2) and a steering unit (3) between the supply connection arrangement and the steering motor (2), the steering unit (3) having a directional section (4) and a measuring section (5), a steering valve (9) being arranged in parallel to the steering unit (3). With such a steering, it is endeavoured to achieve the best possible safety. For this purpose, it is ensured that for each steering direction the directional section (4) comprises a first outlet (A1L, A1R), which is connected to the steering motor (2) by means of a first pipe (23, 24), and a second outlet (A2L, A2R), which is connected to the steering motor (2) by means of a second pipe (25, 26), the first outlet (A1L, A1R) being, in the neutral position of the directional section (4), connected to the measuring section (5), and the first pipe (23, 24) being interruptible by means of a valve arrangement (27, 27a).