摘要:
A pressurized medium assembly includes a first working chamber and a second working chamber. The first and second working chambers are adapted to together produce a load. The pressurized medium assembly includes a first control arrangement adapted to provide a fluid communication between the first working chamber and a pressure line in an on/off manner. The pressurized medium assembly further includes a second control arrangement adapted to provide a fluid communication between the second working chamber and a pressure line. The second control arrangement is adapted to proportionally regulate the pressure in the second working chamber.
摘要:
A hydraulic system for a working machine includes a hydraulic actuator and a first hydraulic machine for supplying fluid to the hydraulic actuator. The hydraulic system further includes a hydraulic transformer for supplying fluid to the hydraulic actuator in parallel with the first hydraulic machine, and an accumulator for fluid. The hydraulic transformer includes a first port and a second port and the transformer is adapted to transform a first pressure and a first flow at the first port to a second pressure and a second flow at the second port. The second port of the hydraulic transformer is in fluid communication with the hydraulic actuator and the first port is in communication with the accumulator.
摘要:
An arrangement for charging an accumulator with hydraulic fluid is provided. The accumulator is used in a hydraulic boom suspension system for a lift arm of a vehicle and the arrangement includes a first hydraulic pump arranged to supply hydraulic fluid to a hydraulic cylinder system of the lift arm, and a second hydraulic pump arranged to supply hydraulic fluid to a second hydraulic system. The second hydraulic pump is further arranged to supply hydraulic fluid for charging the accumulator.
摘要:
A method is provided for controlling a hydraulic system of a working machine. The hydraulic system includes a hydraulic machine for providing hydraulic fluid to one or more actuators of the working machine. The method includes receiving a signal requesting a pump pressure from the hydraulic machine based on the load pressure of a first actuator of the one or more actuators which first actuator has the highest load pressure of the one or more actuators, discriminating the pressure request from the first actuator provided that the first actuator is stalled due to overload or geometrical limitations, and controlling the hydraulic machine to provide a pump pressure based on the load pressure of a second actuator of the one or more actuators which second actuator is in operation and has the second highest load pressure of the one or more actuators, or, if no actuator in addition to the first actuator is present and in operation, controlling the hydraulic machine to provide a predetermined idle pump pressure.
摘要:
A method for controlling lowering of an implement of a working machine is provided. The working machine has a hydraulic system including a hydraulic cylinder for moving the implement and a first control valve for controlling the flow of hydraulic fluid from the piston side of the hydraulic cylinder, and a recovery unit connected to the control valve for recovering energy by receiving a return flow from the piston side of the hydraulic cylinder. The piston side of the hydraulic cylinder and the control valve are connected to each other, and the piston rod side of the hydraulic cylinder is connected to the control valve and to the recovery unit in a point between the control valve and the recovery unit. The method includes identifying a requested lowering speed of the implement, and identifying a desired pressure at the piston side of the hydraulic cylinder and controlling the recovery unit to provide a counter pressure resulting in the desired pressure at the piston side of the hydraulic cylinder, and enabling fluid communication between the piston side of the hydraulic cylinder and the recovery unit, and between the piston side of the hydraulic cylinder and the piston rod side of the hydraulic cylinder, via the control valve, and controlling the control valve in such a way that the flow through the control valve corresponds to the requested lowering speed of the implement.
摘要:
A method is provided for controlling a hydraulic system of a working machine, which hydraulic system includes a first hydraulic machine for providing hydraulic fluid to a first actuator of the working machine, and a second hydraulic machine for providing hydraulic fluid to a second actuator of the working machine and for providing hydraulic fluid to the first actuator. The method includes using a first control mode, and in the first control mode allowing a flow of hydraulic fluid from the second hydraulic machine to the second actuator, wherein the pump pressure of the second hydraulic machine is selected based on the load pressure of the second actuator independently of the load pressure of the first actuator. The method further includes using a second control mode provided that the requested flow to the first actuator exceeds a predetermined threshold value, and in the second control mode allowing a flow of hydraulic fluid from the second hydraulic machine to the first actuator, wherein the pump pressure of the second hydraulic machine is selected based on the highest value of the load pressure of the second actuator and the load pressure of the first actuator.
摘要:
A hydraulic system for a working machine includes at least one work function and a control valve unit for controlling hydraulic fluid to and from the work function, and a recovery unit connected to a return port of the control valve unit for recovering energy from the work function. The system further includes an arrangement for limiting the pressure of the hydraulic fluid at the return port, which pressure limiting arrangement has a pilot-operated valve adapted to set a maximum allowable pressure at the return port of the control valve unit. The pressure is variable by controlling the pilot-operated valve by a control unit.
摘要:
A method is provided for controlling a hydraulic system of a working machine, which hydraulic system includes a first hydraulic machine for providing hydraulic fluid to a first actuator of the working machine, and a second hydraulic machine for providing hydraulic fluid to a second actuator of the working machine and for providing hydraulic fluid to the first actuator. The method includes using a first control mode, and in the first control mode allowing a flow of hydraulic fluid from the second hydraulic machine to the second actuator, wherein the pump pressure of the second hydraulic machine is selected based on the load pressure of the second actuator independently of the load pressure of the first actuator. The method further includes using a second control mode provided that the requested flow to the first actuator exceeds a predetermined threshold value, and in the second control mode allowing a flow of hydraulic fluid from the second hydraulic machine to the first actuator, wherein the pump pressure of the second hydraulic machine is selected based on the highest value of the load pressure of the second actuator and the load pressure of the first actuator.
摘要:
A hydraulic system for a working machine includes at least one work function and a control valve unit for controlling hydraulic fluid to and from the work function, and a recovery unit connected to a return port of the control valve unit for recovering energy from the work function. The system further includes an arrangement for limiting the pressure of the hydraulic fluid at the return port, which pressure limiting arrangement has a pilot-operated valve adapted to set a maximum allowable pressure at the return port of the control valve unit. The pressure is variable by controlling the pilot-operated valve by a control unit.
摘要:
An arrangement for charging an accumulator with hydraulic fluid is provided. The accumulator is used in a hydraulic boom suspension system for a lift arm of a vehicle and the arrangement includes a first hydraulic pump arranged to supply hydraulic fluid to a hydraulic cylinder system of the lift arm, and a second hydraulic pump arranged to supply hydraulic fluid to a second hydraulic system. The second hydraulic pump is further arranged to supply hydraulic fluid for charging the accumulator.