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 device is provided comprising a supply port arrangement having a supply port (P) and a return port (T), a working port arrangement having two working ports (L, R), direction valve means (2) arranged between said supply port arrangement and said working port arrangement, at least two fluid meters (3, 4), each of said fluid meters (3, 4) having a movable metering element (12, 15), said metering elements (12, 15) being connected by a shaft (5), said shaft (5) having an axis, selector valve means (6) being provided, said selector valve means (6) in a first position arranging said fluid meters (3, 4) hydraulically in parallel and in a second position shutting off one of said fluid meters (3, 4), said selector valve means (6) having a valve element (20) shiftable in an direction parallel to said axis. It is an object to reduce wear in said hydraulic steering device in a simple manner.

Abstract: A hydraulic system of a vehicle is provided, said system including: a first hydraulic circuit (1) having a first pressure source (2) and at least a first hydraulic consumer (3, 4), a second hydraulic circuit (5) having a second pressure source (6) and at least a second hydraulic consumer (7), connecting means (10, 11) allowing a flow of hydraulic fluid at least from said first hydraulic circuit (1) to said second hydraulic circuit (5), and control means (16) for controlling operation of said hydraulic consumers (3, 4, 7). Such a hydraulic system should allow safe operation of a vehicle with low energy consumption of the hydraulic system.

Abstract: A hydraulic valve arrangement (1) is provided comprising comprising a supply port arrangement having a high pressure port (2) and a low pressure port (4), a working port arrangement having two working ports (6, 7), a first valve (13) arranged between said high pressure port (2) and said working port arrangement (6, 7), a second valve (14) arranged between said low pressure port (4) and said working port arrangement (6, 7), a controller (19) for controlling said first valve (13) and said second valve (14), said controller (19) having an input connection (20) for receiving a signal of an operator input device, and a regenerative flow path which can be established by means of at least one of said first valve (13) and said second valve (14). The function of such a hydraulic valve arrangement should be enhanced. To this end said controller (19) said controller interrupts said regenerative flow path when a feed pressure at said working port arrangement (6, 7) exceeds a predetermined pressure level.

Abstract: The invention provides a steering system comprising a controlled element which is movable in a neutral area comprising a neutral position and in areas on opposite sides of the neutral area based on a steering input and a handle for requesting a desired position for the controlled element. The handle is movable between set-points in a center zone comprising a center set-point and set-points on opposite sides of the center zone. Furthermore, a steering unit is arranged to receive set-points from the handle, to determine a corresponding controlled position of the controlled element, and to move the controlled element to said controlled position. In order to prevent or reduce jerks, the steering unit is adapted to vary a speed by which the controlled element is moved to the controlled position. The speed is variable in dependence of the received set-point.

Abstract: A valve group includes an inlet module and at least one service module connected to the inlet module, the inlet module having a housing, a pressure port, a pressure gallery, a tank port, a tank gallery, a spool movable in the housing to interrupt in a first position a connection between the pressure port and the pressure gallery and to connect in a second position the pressure port and the pressure gallery. A first pressure transducer is provided to detect a first pressure in the pressure gallery and a second pressure transducer is provided to detect a second pressure in the tank gallery, the pressure transducers being connected to a controller determining the position of the spool based on the pressures read from the pressure transducers.

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: The invention relates to a fluid distribution valve (1, 25, 29, 37, 43), comprising at least a first fluid port (2), a second fluid port (3) and a third fluid port (4). These ports are connecting to a fluid distribution chamber (5). The second fluid port (3) can be selectively connected to the first fluid port (2) and/or the third fluid port (4) through said distribution chamber (5). The second fluid port (3) is arranged between the first fluid port (2) and the third fluid port (4).

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 method for controlling steering of a vehicle (1) is provided, the vehicle (1) defining two or more steerable axes, and the vehicle (1) comprising a number of wheels (2), each of said wheels (2) being associated with one of said steerable axes in such a manner that steering of a given wheel (2) 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 (4) and a longitudinal center axis defined by the vehicle (1). The second steering input defines an angle between the virtual steering axis (4) and the longitudinal center axis. The third steering input defines a position of a center of rotation (5) along the virtual steering axis (4).

Abstract: A hydraulic steering device is provided comprising a supply port arrangement having a pressure port (P) and a tank port (5), a working port arrangement having two working ports (L, R), a main flow path (14) between the pressure port (P) and the working port arrangement, a return flow path (16) between the working port arrangement and the tank port (5), flow meter means (15) being arranged in said main flow path (14), an amplification flow path (17) being arranged in parallel to said main flow path (14), said amplification flow path (17) being connected to said main flow path (14) downstream said flow meter means (15) 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 (15) in case a flow through said main flow path (14) is blocked by said flow meter (15).

Abstract: A hydraulic steering arrangement (1) is provided comprising a static steering unit (2) and an adjustable pressure source (3) connected to a pressure port (4) of said steering unit (2) and having a load sensing port (21). Such a steering unit should enable a fast reaction of the steering unit. To this end said pressure source (3) is a dynamic pressure source having an orifice (Adyn) outputting hydraulic fluid to said load sensing port (21), a load sensing line (22) connecting said load sensing port (21) and a low pressure port (11), a control valve (24) being arranged in said load sensing line (22) between said load sensing port (21) and said low pressure port (11), said control valve (24) being actuated by a control pressure within said steering unit (2) and throttling a flow through said load sensing line (22) depending on said control pressure.

Abstract: An electrohydraulic control valve comprising a valve element that is displaceable in a first direction by a pressure in a first pressure chamber and in a second direction by a pressure in a second pressure chamber. The first pressure chamber is connectable to a high pressure supply and a low pressure supply. The second pressure chamber is connectable to the high pressure supply and the low pressure supply. A first magnetic valve is connected to the first pressure chamber and a second magnetic valve is connected to the second pressure chamber. A third magnetic valve is connected to the high pressure supply and to the first magnetic valve and to the second magnetic valve. It is intended to provide an electrohydraulic control valve that is both reliable and less complex than previous valve arrangements. To this end the first magnetic valve and the second magnetic valve are three-way valves.

Abstract: In open-circuit hydraulic systems (1), the cross-sections of the supply lines (6) and input valves of the hydraulic pump (3) have to be large, so that sufficient flow flux can be provided. This hinders a reduction of the size of the pump and the whole hydraulic system. It is suggested that the supply flow (7) of a hydraulic pump (3) is charged by a second, charging pump (2), to a mid-pressure level (7). The cross-sections of the supply flow areas can thus be decreased.

Abstract: The invention concerns a rotation angle sensor, in particular a steering angle sensor (1) for a steering unit, with a housing (2) comprising an exterior (8), a pick-up sensor (7) arranged in a sensor chamber in the housing (2) to perform rotary movements around a rotation axis, and a stationary receiver interacting with the pick-up sensor (7). It is endeavored to make such steering angle sensors fit for rough environmental conditions. For this purpose, the sensor chamber is connected to the exterior (8) via at least one free space (16).

Abstract: Disclosed is a cylinder assembly for a fluid-working machine. The assembly includes a body having a first end and a second end. The body further includes a cylinder, a poppet valve seat and a face-sealing annular valve seat. The cylinder is open to the first end and configured to receive a reciprocating piston. The poppet and annular valve seats extend around an axis through the cylinder. An annular valve including the annular valve seat and an annular valve member extends around the cylinder. Thus, the cylinder assembly is compact.

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 steering device (1) 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 (14) between the supply port (P) and the working port arrangement, a return flow path (16) between the working port arrangement and the tank port (T), flow meter means (15) being arranged in said main flow path (14), said flow meter means (15) comprising at least two flow meters (27, 28) and a flow meter valve means (30), said flow meter valve means (30) in a first operation mode connecting at least two flow meters (27, 28) in parallel and in a second operation mode making inactive at least one flow meter (27). Such a steering device should be operated comfortable for a driver.