Hydraulic system

A hydraulic system for a working vehicle, the hydraulic system comprising:

• a first group of hydraulically actuated devices which are actuated simultaneously to carry out a first set of functions of said working vehicle and which are not actuated in order to carry out a second set of functions of said working vehicle;
• a second group of hydraulically actuated devices which are actuated simultaneously to carry out the second set of functions of said working vehicle and which are not actuated in order to carry out the first set of functions of said working vehicle;
• two or more hydraulic pump assemblies for supplying hydraulic fluid to the hydraulically actuated devices of the first and second groups;
• wherein the hydraulic system is arranged so that each hydraulically actuated device of the first group is supplied by a different one of the hydraulic pump assemblies;
• wherein the hydraulic system is arranged so that each hydraulically actuated device of the second group is supplied by a different one of the hydraulic pump assemblies;
• and
• wherein at least one of the hydraulic pump assemblies is arranged for supplying hydraulic fluid to both a hydraulically actuated device of the first group and a hydraulically actuated device of the second group;
• and
• wherein the first set of functions relates to movement of a working arm of said working vehicle, and wherein the first group of hydraulically actuated devices comprises two or more actuators associated with movement of said working arm;
• and/or wherein the second set of functions relates to movement of a chassis of said working vehicle, and wherein the second group of hydraulically actuated devices comprises two or more actuators associated with movement of the chassis.

A hydraulic system for a working vehicle, the hydraulic system comprising:

• a plurality of hydraulically actuated devices;
• one or more hydraulic pump assemblies for supplying a variable output of hydraulic fluid to the hydraulically actuated devices;
• and
• a plurality of proportional control valves, wherein the hydraulic system is arranged such that hydraulic fluid exiting each of the hydraulically actuated devices flows through a restriction of a respective one of the proportional control valves;
• wherein the hydraulic system is configured to control a flow of hydraulic fluid supplied to the hydraulically actuated devices by varying the output of hydraulic fluid from the one or more hydraulic pump assemblies, and to control a flow of hydraulic fluid exiting each of the hydraulically actuated devices via adjusting a restriction area of the respective one of the proportional control valves;
• and
• wherein the number of hydraulic pump assemblies is less than the number of hydraulically actuated devices, and wherein one or more of the hydraulic pump assemblies is a shared pump assembly for supplying hydraulic fluid to two or more of the hydraulically actuated devices.

A hydraulic system for a working vehicle, the hydraulic system comprising:

• a plurality of hydraulically actuated devices;
• a plurality of hydraulic pump assemblies for supplying a variable output of hydraulic fluid to the hydraulically actuated devices;
• and
• a plurality of proportional control valves, wherein the hydraulic system is arranged such that hydraulic fluid exiting each of the hydraulically actuated devices flows through a restriction of a respective one of the proportional control valves;
• and
• wherein the hydraulic system is configured to control a flow of hydraulic fluid supplied to the hydraulically actuated devices by varying the output of hydraulic fluid from the hydraulic pump assemblies, and to control a flow of hydraulic fluid exiting each of the hydraulically actuated devices via adjusting a restriction area of the respective one of the proportional control valves,
• wherein the plurality of hydraulically actuated devices comprises a left-hand track motor for actuating a left-hand track of the working vehicle and a right-hand track motor for actuating a right-hand track of the working vehicle, and wherein the left-hand track motor is supplied with hydraulic fluid from a first of the hydraulic pump assemblies and the right-hand track motor is supplied with hydraulic fluid from a second of the hydraulic pump assemblies.

A hydraulic system for a working vehicle, the hydraulic system comprising:

• a plurality of hydraulically actuated devices;
• a plurality of hydraulic pump assemblies for supplying a variable output of hydraulic fluid to the hydraulically actuated devices;
• and
• a plurality of proportional control valves, wherein the hydraulic system is arranged such that hydraulic fluid exiting each of the hydraulically actuated devices flows through a restriction of a respective one of the proportional control valves;
• and
• wherein the hydraulic system is configured to control a flow of hydraulic fluid supplied to the hydraulically actuated devices by varying the output of hydraulic fluid from the hydraulic pump assemblies, and to control a flow of hydraulic fluid exiting each of the hydraulically actuated devices via adjusting a restriction area of the respective one of the proportional control valves;
• wherein the plurality of hydraulically actuated devices comprises a boom actuator for raising or lowering a working arm of the working vehicle and a dipper arm actuator for pivoting a dipper arm of the working vehicle relative to a boom of the working vehicle, and wherein the boom actuator is supplied with hydraulic fluid from one of the hydraulic pump assemblies and the dipper arm actuator is supplied with hydraulic fluid from a different one of the hydraulic pump assemblies.

A hydraulic system for a working vehicle, the hydraulic system comprising:

• a hydraulically actuated device;
• a hydraulic pump assembly for supplying a variable output of hydraulic fluid to the hydraulically actuated device;
• and
• a proportional control valve, wherein the hydraulic system is arranged such that hydraulic fluid exiting the hydraulically actuated device flows through a restriction of the proportional control valve;
• wherein the hydraulic system is configured to control a flow of hydraulic fluid supplied to the hydraulically actuated device by varying the output of hydraulic fluid from the hydraulic pump assembly, and to control a flow of hydraulic fluid exiting the hydraulically actuated device via adjusting a restriction area of the proportional control valve;
• and
• wherein the hydraulic pump assembly is driven by an electric motor, and wherein the hydraulic system is configured such that output of hydraulic fluid from the hydraulic pump assembly is varied by adjusting a rotation speed of said electric motor.