A hydraulic system (40) for a work machine comprising a priority circuit (41) including at least a first priority actuator (47, 48) and a priority control valve (58) for controlling the supply of hydraulic fluid to the first priority actuator (47, 48) and for providing a load sense signal indicative of the load acting on the first priority actuator (47, 48); an auxiliary circuit (42) including at least a first auxiliary actuator (51) and at least a first auxiliary control valve (80) for controlling the supply of hydraulic fluid to the first auxiliary actuator (51); at least a first pump (46) for producing a flow of hydraulic fluid; and a priority valve (74) for distributing the flow from the pump (46) to the priority circuit (41) and auxiliary circuit (42) for operating the respective actuators thereof, with priority being given to the priority circuit (41) as a function of the load sense signal.

A hydraulic arrangement for distributing a fluid in pressure coming from a source among multiple hydraulic units of a work vehicle. At least one of the hydraulic units provides an electronic load sensing signal and of the hydraulic units provides a hydraulic load sensing signal. The hydraulic arrangement includes a priority valve configured to divide the flow of fluid between the hydraulic units. The priority valve and source are hydraulically controlled by a first hydraulic load sensing signal resulting as the greatest of a plurality of hydraulic load pressure signals taken from the hydraulic unit. The hydraulic arrangement also includes a conversion unit configured to transform an electronic load sensing signal of at least one of the hydraulic units in an equivalent hydraulic load sensing signal so as to define the first hydraulic load sensing signal.

A steering assistance device includes: a steering angle detection unit that detects the steering angle of a vehicle; a pump unit that performs steering assistance of the vehicle by using oil pressure; a motor that performs steering assistance of the vehicle by using electrical power; and a steering control unit that causes the pump unit to perform steering assistance with the steering assistance amount thereof reduced by a predetermined amount from the predetermined steering assistance amount, and causes the motor to perform steering assistance, in a case where the pump unit can perform steering assistance in a steering assistance amount predetermined for the detected steering angle.

A steering assistance device includes: a steering angle detection unit that detects the steering angle of a vehicle; a pump unit that performs steering assistance of the vehicle by using oil pressure; a motor that performs steering assistance of the vehicle by using electrical power; and a steering control unit that causes the pump unit to perform steering assistance with the steering assistance amount thereof reduced by a predetermined amount from the predetermined steering assistance amount, and causes the motor to perform steering assistance, in a case where the pump unit can perform steering assistance in a steering assistance amount predetermined for the detected steering angle.

A hydraulic system for an electric working vehicle or hybrid working vehicle of the kind having an electric source of power and an alternative source of power, the hydraulic system comprising: one or more hydraulically actuated devices; and a hydraulic pump configured to supply hydraulic fluid to the one or more hydraulically actuated devices; wherein the hydraulic pump is configured to operate in a low output state when a flow of hydraulic fluid is not required by the one or more hydraulically actuated devices; and wherein the hydraulic system is configured to use hydraulic fluid supplied by the hydraulic pump in the low output state for one or more auxiliary functions of the hydraulic system.

The operability can be improved when the rotational speed of the engine is low and the working device actuator and the steering actuator are operated in a combined manner, while the configuration of prioritizing the operation of the steering actuator is maintained. A control device (70) included in a wheel loader (1) determines whether a working device (4) is in load lifting operation or not based on the pressure that is between a working device directional switching valve (44) and an orifice (45) and is detected by a pressure sensor (71), and reduces the opening area of a steering control valve (37) when determining that the rotational speed of an engine (14) detected by a rotational speed sensor (72) is equal to or less than a predetermined threshold (Ns) and a working device is in the load lifting operation.

The operability can be improved when the rotational speed of the engine is low and the working device actuator and the steering actuator are operated in a combined manner, while the configuration of prioritizing the operation of the steering actuator is maintained. A control device (70) included in a wheel loader (1) determines whether a working device (4) is in load lifting operation or not based on the pressure that is between a working device directional switching valve (44) and an orifice (45) and is detected by a pressure sensor (71), and reduces the opening area of a steering control valve (37) when determining that the rotational speed of an engine (14) detected by a rotational speed sensor (72) is equal to or less than a predetermined threshold (Ns) and a working device is in the load lifting operation.

A hydraulic system for an electric working vehicle or hybrid working vehicle of the kind having an electric source of power and an alternative source of power, the hydraulic system comprising: one or more hydraulically actuated devices; and a hydraulic pump configured to supply hydraulic fluid to the one or more hydraulically actuated devices; wherein the hydraulic pump is configured to operate in a low output state when a flow of hydraulic fluid is not required by the one or more hydraulically actuated devices; and wherein the hydraulic system is configured to use hydraulic fluid supplied by the hydraulic pump in the low output state for one or more auxiliary functions of the hydraulic system.

The self-propelled construction machine according to the invention has a braking device which comprises at least one hydraulically actuated braking device actuating device 8 which has a pressure chamber 10A, 11A that can be acted upon with a hydraulic fluid. The braking device actuating device 8 is formed in such a way that, in a locking position, the running gear 3B, to which the braking device actuating device 8 is assigned, is braked, and, in an operating position, the running gear is unbraked. In addition, the construction machine according to the invention has a hydrostatic steering device 9, which comprises at least one hydraulic steering device actuating device 22. In the event of a malfunction in the supply of hydraulic fluid to the braking device actuating device 10, 11, the hydraulic system has a manually actuated emergency-operation valve arrangement 16 which is formed in such a way that, after the manual actuation thereof, a fluid connection is created between the steering device actuating device 22 and the pressure chamber 10A, 11A of the braking device actuating device 10, 11. The emergency-operation valve arrangement 16 has a valve block 27 in which flow paths are formed which can be shut off by means of shut-off screws 31, 32.

The invention relates to a hydraulic steering facility for mobile systems, with a steering circuit for a steering facility and a working circuit for a working hydraulic system, whereby the steering circuit and the working hydraulic system are connected to a supply pump via a shared flow dividing valve and the flow dividing valve is connected to a load signal connection of the steering device. It is provided that the steering facility has an adjustable input choke that is connected via an inflow connection of the steering facility to the flow dividing valve, between the load signal connection and downstream of the input choke, a parallel circuit consisting of a choke and an adjustable second load signal choke is arranged, and the load signal connection is further connected via an adjustable first load signal choke to a return flow connection of the steering facility.