Abstract: A control device (1) 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 (7) between said pump and tank connections (P, T) being open when said sleeves are in a neutral position, said bypass throttle means (7) 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.

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 provides a fluid controller for controlling a machine, e.g. for steering a vehicle. The controller comprises a housing defining an inlet port connected to the source and an outlet port connected to the pressure operated device. The flow rate is controlled by movement of a valve member within the housing, and a processor provides a reference which is indicative of a desired position of the valve member relative to the housing. The fluid controller comprises a fault detection system based on an observer. The observer calculates a theoretically correct position of the valve member relative to the housing for a given reference, and compares this position to an obtained position of the valve member relative to the housing. The difference between the positions is compared with a threshold value. In order to dynamically change the sensitivity of the system, the threshold value is scaled based on a gradient of the reference.

Abstract: The invention relates to a valve actuator (2), comprising a magnetic core (6) with an interspace (8) and at least one bifurcating branch (7), at least one variable magnetic field generating device (16), at least one permanent magnetic field generating device (13) and at least one movable magnetic component (12), wherein the bifurcating branch (7) defines a first region (4) and a second region (5) of said magnetic core (6).

Abstract: The invention concerns a fluid rotary machine (1) with a housing (2), a shaft (3) led out of the housing (2) and a sensor arrangement (10) comprising a transmitter (12) in active connection with the shaft (3), and a receiver (15). It is endeavoured to arrange the sensor arrangement in an advantageous manner on the fluid rotary machine. For this purpose, the sensor arrangement (10) comprises an accommodation area, in which the transmitter (12) is arranged, the accommodation area being in fluid connection with the inside of the housing (2) and sealed towards the outside, and the receiver (15) is arranged outside the housing (2) and the accommodation area.

Abstract: The invention concerns a fluid rotary machine (1) with a housing (2), a shaft (3) projecting from the housing (2), and being rotatable around an axis (4) and forming part of a movement chain, and a sensor arrangement (10) comprising a transmitter (12) and a receiver (15). It is endeavoured to find a simple solution for detecting the rotation of the shaft with a relatively high accuracy. For this purpose, a channel (21) is provided in the movement chain, and the transmitter (12) is connected to a transfer element (19) transferring a torque that is led through said channel (21) to a section of the movement chain that is farther away from the transmitter (12) than a transmitter-side end of the movement chain.

Abstract: A fluid working machine comprises a controller (12) and a working chamber (2) of cyclically varying volume. The working, chamber has both an electronically controllable primary low pressure valve (14) and a secondary low pressure port (22) associated therewith, each of which is openable and closable in phased relation to cycles of working chamber volume to bring the working chamber into fluid communication with a low pressure manifold (16, 26). At least the primary low pressure valve is under the active control of the controller to enable the controller to determine the net displacement of fluid by the working chamber on a cycle by cycle basis. The primary low pressure valve and the secondary low pressure port are openable concurrently during a portion of at least some cycles of working chamber volume to enable fluid to flow into or out of the working chamber concurrently through both the primary low pressure valve and the secondary low pressure port.

Abstract: The invention concerns a hydraulic valve arrangement (1) with at least two valve modules (2-6), each having a supply channel arrangement with a high-pressure channel (9) and a low-pressure channel (15), a working connection arrangement with at least one working connection (A, B), one directional valve arrangement (16) between the supply channel arrangement (9, 15) and the working connection arrangement (A, B) and a compensation arrangement (19), which is acted upon by a pressure in a load-sensing arrangement. It is endeavored to increase the number of control possibilities. For this purpose, the load-sensing arrangement of at least one valve module (2-6) has a pressure influencing arrangement (25-29) that differs from a pressure influencing arrangement (25-29) of a load sensing arrangement of another valve module (2-6).

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: The invention provides a method of calibrating a steering system for a vehicle, e.g. an off-highway machinery, to allow automatic steering based on input from a position or tracking system, e.g. based on a Global Positioning System (GPS). At least two records, each comprising a position value and a curvature value are established. The position value represents a position of the steered element, e.g. a position of a steered wheel of the vehicle, and the curvature value could e.g. be expressed as a radius of a curve followed by the vehicle with that position of the steered element. The curvature value is determined by the positioning system during movement of the vehicle. Due to the records, it is easy to calibrate or recalibrate the system and the invention is therefore applicable e.g. in connection with manufacturing of vehicles in small batch numbers, e.g. for one of a kind production or for retrofitting of steering components to existing vehicles.

Abstract: The invention concerns a hydraulic valve arrangement (1) with a supply connection arrangement comprising a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement comprising two working connections (A, B), which can be connected to a motor (4), a directional valve arrangement (5) located between the supply connection arrangement (P, T) and the working connection arrangement (A, B), and a compensation valve (15) acted upon in a first activation direction by a pressure in a first pressure chamber (33), which is connected to a load-sensing pipe (LS), and, if required, by a spring (32), and in a second activation direction opposite to the first activation direction by a pressure downstream of the directional valve arrangement (5), said pressure acting in a second pressure chamber (34), the compensation valve (15) having an inlet (14) and an outlet (19).

Abstract: The invention concerns a hydraulic steering (1) with a steering valve (7) located between a supply connection arrangement (P, T) and a steering motor (2). It is endeavored to improve the safety of such a steering. For this purpose, the steering valve (7) has a hydraulic drive (9, 10) with a pilot valve arrangement (11) supplied by a pressure control valve (5), a stop valve (16) being located between the pressure control valve (5) and the pilot valve arrangement (11).

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 valve arrangement (1) with a supply connection arrangement comprising a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement comprising two working connections (A, B), which can be connected to a motor (4), a directional valve arrangement (5) located between the supply connection arrangement (P, T) and the working connection arrangement (A, B), and a compensation valve (15) acted upon in a first activation direction by a pressure in a first pressure chamber (33), which is connected to a load-sensing pipe (LS), and, if required, by a spring (32), and in a second activation direction opposite to the first activation direction by a pressure downstream of the directional valve arrangement (5), said pressure acting in a second pressure chamber (34), the compensation valve (15) having an inlet (14) and an outlet (19).

Abstract: The invention concerns a hydraulic machine with a set of teeth, having a toothed ring with an inner toothing and a gear wheel with an outer toothing, the gear wheel rotating and orbiting in the toothed ring, the inner toothing and the outer toothing touching each other in contact areas, thus separating pressure chambers, and with a valve arrangement controlling a connection between a connection arrangement having a high pressure connection and a low pressure connection, and the pressure chambers. It is endeavoured to achieve a stable operation, particularly with low speeds. For this purpose, each contact area is provided with an opening, which, at the time when a pressure chamber reaches an extreme value of its volume, produces a short-circuiting with the neighbouring pressure chamber.

Abstract: The invention concerns a hydraulic valve arrangement (1) having at least two working connections (A, B), a check valve (5, 6) being allocated to each working connection (A, B), and a pressure relief valve (7, 8) being allocated to each check valve (5, 6), each pressure relief valve (7, 8) being connected to a control pressure passage (17, 18). The valve arrangement shall ensure a reliable, pressure-less lowering, also in connection with single-actuated consumers, and further enable a pressure-less float position. For this purpose, the check valves (5, 6) can be opened by means of tappets (20, 21), whose sides facing away from the check valves (5, 6) are ending in a pressure chamber (22), which is connected to the control pressure passage (17, 18) of one of the pressure relief valves (7, 8).

Abstract: The invention relates to a hydraulic pump or hydraulic motor having an orbiting cardan shaft. The hydraulic pump or motor includes a housing having an end cover and a port plate. The cardan shaft is mounted in the housing and extends through the port plate. A rotation speed sensor is fixed to the port plate and includes a sensor probe obtaining its signal from the orbiting cardan shaft. A piston may be in contact with the cardan shaft and moving forward and back due to the orbital motion of the cardan shaft. The sensor probe then obtains its signal from the movement of the piston.

Abstract: The invention concerns a hydraulic steering (1) with a steering unit (2) with feedback behaviour, a steering motor (8) connected to the steering unit (2) via working pipes (L, R), a steering member (6) and a feedback suppression device (9), which is located in at least one working pipe (L, R). It is endeavoured to change the feedback behaviour of such a steering in a simple manner. For this purpose, the feedback suppression device (9) has a valve arrangement (10) with hydraulic control inlet (C).

Abstract: If a hydraulic system has several modes of operation, in particular a mode with a high pressure demand (II) and a mode with a high fluid flow demand (II), the hydraulic fluid pump has to be built with an accordingly high fluid flow output. Such a pump is expensive. Therefore it is suggested, to provide two pumps. I.e. a controllable main pump (2) is provided, which supplies the hydraulic consumer (6) during phases (I) of high pressure demand. During phases (II) of high fluid flow demand, normally, relatively low pressures are sufficient. Therefore, it is suggested to provide a parallel boost pump (9), which supplies the hydraulic consumer (6) in addition to the high pressure pump (2), if a high fluid flow is needed. Excess fluid flow output is avoided by controlling the fluid output flow of main pump 2.