The invention relates to a pressure supply device for prioritised volume flow splitting, in particular in mobile working machines, comprising at least one adjusting pump (2) controllable by means of an LS signal as main pump, a constant-displacement pump (4) as an auxiliary pump, two pressure balances, a system to be supplied primarily, in particular in the form of steering hydraulics (PL), which outputs an LS signal, a system to be supplied secondarily, which outputs a further LS signal, in particular in the form of working hydraulics (PA), and a further system to be supplied hydraulically, in particular in the form of brake hydraulics (PB), wherein one pressure balance (DW1) is used to supply the system (PL) to be supplied primarily and/or the further hydraulic system (PB), the other pressure balance (DW2) is used to supply the system (PL) to be supplied primarily and/or the system (PA) to be supplied secondarily,

A hydraulic steering arrangement (2) is described having a main flow path (8) with a flow meter (9) and an amplification flow path (10) opening into the main flow path (8) at a connecting point (11) located between the flow meter (9) and a working port arrangement (L, R). Such a steering arrangement should have in a simple way a large flow of the hydraulic fluid to the working port arrangement. To this end pressure increasing means (17) are arranged in the main flow path (8) upstream the connecting point (11).

A hydraulic steering arrangement 1 is described comprising a supply port arrangement having a pressure port (4) and a tank port (5), a working port arrangement having two working ports (6, 7), a steering unit (2) arranged in a flow path (9) between the supply port arrangement (4, 5) and the working port arrangement (6, 7), and a second flow path (13) in form of an amplification flow path bridging the steering unit (2) and having an amplification orifice (A.sub.U1) which is controlled as function of the steering unit (2). Such a steering arrangement should have a possibility to change the steering behaviour. To this end at least a third flow path (14) in form of an amplification flow path is arranged in parallel to the second flow path (13), wherein the second/or the third flow path (13, 14) comprise an valve (15).

In order to provide a steering device for a construction/transport/farm machine which can be steered by means of a steering wheel operation and by means of a lever operation (or automatic steering) such that not only can a mechanism for prioritizing the steering wheel operation be achieved with a simple configuration, but the mechanism can also be caused to stably operate, the steering device is provided with: steering cylinders 1; a steering valve 2; a pump 3; a steering wheel control valve 4; an electromagnetic control valve 5 for lever/automatic steering; a steering wheel priority valve 6; and a change-over valve 7 which, upon sensing a load pressure generated when the steering wheel control valve 4 is operated, switches the setting of the steering wheel priority valve 6 by using the load pressure, wherein the change-over valve 7 for switching the setting of the steering wheel priority valve 6 has a two-port two-position configuration whereby a drain oil passage of the steering wheel priority valve 6 is closed by utilizing the load pressure generated when the steering wheel control valve 4 is operated.

A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

A steering apparatus for an industrial vehicle includes: a manual steering circuit which includes a first valve opened/closed according to an operation of a steering wheel and supplies hydraulic oil discharged from a hydraulic pump to a steering cylinder through the first valve; an automatic steering circuit which includes a second valve opened/closed according to a calculation result of automatic operation control and supplies the hydraulic oil discharged from the hydraulic pump to the steering cylinder through the second valve; and a branching valve which is disposed between the hydraulic pump and the first and second valves and branches the hydraulic oil to the manual steering circuit and the automatic steering circuit. The branching valve is a priority valve which preferentially supplies the hydraulic oil to the manual steering circuit at a designed flow rate equal to or larger than a predetermined flow rate for operating the steering cylinder.

A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

A vehicle includes a chassis, a tractive element coupled to the chassis, and a parking brake system. The chassis includes at least one of a transmission or a structural frame. The parking brake system includes a parking brake configured to brake the tractive element when engaged. The parking brake is configured to be disengaged to permit rotation of the tractive element in response to the parking brake receiving a fluid. The parking brake system includes a fluid supply configured to supply the fluid to the parking brake to disengage the parking brake. The fluid supply is configured to stop supplying the fluid in response to a component of the vehicle ceasing operation. The parking brake system includes a pump coupled to the chassis and configured to supply the fluid to the parking brake at least when the component of the vehicle is not operating.

A hydraulic steering arrangement (1) including a supply port (2), a return port (4), a working port arrangement having two working ports (5, 6), a main flow path (7) between the supply port (2) and one of the working ports (5) and a return flow path (8) between the other working port (6) and the return port (4), wherein the main flow path (7) includes a main orifice (A1), a flow meter (9), a first flow meter orifice (A2) upstream the flow meter (9), a second flow meter orifice (A3) downstream the flow meter (9), and a first working port orifice (A4), the return flow path (8) includes a second working port orifice (A5), a load sensing point (17) is arranged between the main orifice (A1) and the first flow meter orifice (A2), a drain orifice (Ad) is arranged between the load sensing point (17) and the return port (4), and a priority valve arrangement (10) is arranged between the supply port (2) and the main orifice (A1). Such a steering arrangement should enable a high steering speed without loss of comfort. To this end a load sensing port (16) of the priority valve arrangement (10) is connected to the load sensing point (17), characterized in that a priority outlet (CF) of the priority valve arrangement (10) is directly connected to the main orifice (A1), the load sensing port (16) of the priority valve arrangement (10) is directly connected to the load sensing point (17) and the main flow path (7) includes a check valve (24) between the load sensing point (17) and the working port (5) of the main flow path (7), the check valve (24) opening in a direction towards the working port (5).

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.