Volvo Construction Equipment Ab

Volvo Wheel Loaders Ab

Bo Vigholm

Andreas Ekvall

Markku Palo

Kim Heybroek

Lennart Strandberg

Johan Hallman

Joakim Sjögren

Nils-Erik Bånkestad

Gunnar Löwestrand

Reno Filla

Joakim Unnebäck

Gunnar Lindgren

Karl Uebel

Patrik Wahlström

Johan Lillemets

Erik Carldén

Patrik Stener

Jan Karlsson

Kausihan Selvam

Benny Truong

Linda Åberg

Stefan Johansson

Joakim Fröberg

Sven-Alie Carlsson

Rauno Räisanen

Patrik Fransson

Kjell Sjogren

Stefan Harald Salomonsson

Sven-&angst;ke Carlsson

Method for controlling a hydraulic system for a working machine, the system including a first electric machine connected to a first hydraulic machine the first hydraulic machine including an input side and an output side a second electric machine connected to a second hydraulic machine the second hydraulic machine including a high-pressure side and a low-pressure side the high-pressure side connected to the input side; a hydraulic consumer coupled to the output side via a supply line and configured to be powered by the first hydraulic machine; a first return line hydraulically coupling the hydraulic consumer to the input side and to the high-pressure side; wherein the method includes detecting a return flow from the hydraulic consumer through the first return line; and controlling the second hydraulic machine to maintain a pressure in the first return line at a pressure level higher than a predetermined minimum pressure level.

Method for controlling a hydraulic system of a working machine

A hydraulic system for a working machine, the system comprising: an electric machine connected to a first hydraulic machine and to a second hydraulic machine via a common axle, an output side of the second hydraulic machine being connected to an input side of the first hydraulic machine, wherein the first hydraulic machine is a variable displacement hydraulic machine with unidirectional flow; at least one hydraulic consumer hydraulically coupled to an output side of the first hydraulic machine via a supply line and configured to be powered by the first hydraulic machine; a first return line hydraulically coupling the hydraulic consumer to the input side of the first hydraulic machine.

Hydraulic system and a method for controlling a hydraulic system of a working machine

A hydraulic system for a working machine includes a first electric machine connected to a first hydraulic machine; a second electric machine connected to a second hydraulic machine, an output side of the second hydraulic machine being connected to an input side of the first hydraulic machine; at least one hydraulic consumer hydraulically coupled to an output side of the first hydraulic machine via a supply line and configured to be powered by the first hydraulic machine; and a valve arrangement arranged between the hydraulic consumer and the first and second hydraulic machines, wherein the valve arrangement is configured to control a return flow of hydraulic fluid from the hydraulic consumer to either the input side of the first hydraulic machine or an input side of the second hydraulic machine based on a requested output pressure from the first hydraulic machine.

A hydraulic system includes a first electric machine connected to a first hydraulic machine and a second electric machine connected to a second hydraulic machine. An output side of the second hydraulic machine is connected to an input side of the first hydraulic machine. A hydraulic consumer is hydraulically coupled to an output side of the first hydraulic machine via a supply line and is powered by the first hydraulic machine. A return line hydraulically couples the hydraulic consumer to an input side of the first hydraulic machine. The second hydraulic machine provides a flow of hydraulic fluid to the input side of the first hydraulic machine if a requested flow from the first hydraulic machine exceeds a flow of the return line and recuperates energy if the requested flow from the first hydraulic machine is lower than the flow of the return line.

Hydraulic system for a working machine

A method is disclosed for controlling brake forces of a working machine, the working machine including a frame and two front wheels and two rear wheels mounted to the frame, the working machine further including a front wheel brake arranged to brake at least one of the front wheels, and a rear wheel brake arranged to brake at least one of the rear wheels, the front wheel brake being controllable independently of the rear wheel brake, and vice versa, the working machine further including an implement connected to the frame so as to be movable in relation to the frame. The method includes determining a position of the implement in relation to the frame, and distributing the brake forces between the front and rear wheel brakes at least partly based on the determined implement position.

Method for controlling brake forces of a working machine

The invention relates to a drive system for a working machine, the drive system including: a gearbox; an internal combustion engine having an engine output shaft; a power takeoff coupled to the engine output shaft; a torque converter having an input shaft operatively coupled to the engine and an output shaft operatively coupled to the gearbox; a hydraulic cooling fan; a hydraulic fan pump coupled to the power takeoff and connected to the hydraulic fan via a first hydraulic valve. The drive system further includes: a hydraulic motor coupled to the gearbox and configured to provide power to the gearbox for vehicle propulsion, wherein the hydraulic motor is coupled to the hydraulic fan pump via a second hydraulic valve and arranged to receive power from the hydraulic fan pump. The invention further relates a method for controlling the described drive system.

Drive system for a working machine and a method for controlling the drive system

A hydraulic fluid tank arrangement for a working machine is provided, the arrangement including a hydraulic fluid tank; an inlet portion for receiving hydraulic fluid into the hydraulic fluid tank; and an oil filter arranged in fluid communication with the inlet portion; wherein the hydraulic fluid tank arrangement further includes a gas removal device arranged in fluid communication with the oil filter downstream the inlet portion and upstream the oil filter for removing gas from the hydraulic fluid before the hydraulic fluid reaches the oil filter. A method for removing gas from hydraulic fluid contained in a hydraulic fluid tank arrangement is also provided.

Hydraulic fluid tank arrangement

A hydraulic system for a working machine is a load sensing system and includes a hydraulic actuator for movement of an implement and a control valve having an inlet valve and an outlet valve for controlling the flow of hydraulic fluid from a pump to the hydraulic actuator and for draining hydraulic fluid from the hydraulic actuator, respectively. The hydraulic system also includes an arrangement for determining the load on the hydraulic actuator. The hydraulic system further includes a valve for disconnecting the flow of hydraulic fluid from the pump to the hydraulic actuator, while allowing another flow of hydraulic fluid to the hydraulic actuator, provided that the determined load on the hydraulic actuator exceeds a threshold value.

Load sensing hydraulic system for a working machine, and a method for controlling a load sensing hydraulic system

A hydraulic system for a working machine is a load sensing (LS) system and includes a first hydraulic actuator and a first control valve for controlling the flow of hydraulic fluid from a pump to the first hydraulic actuator and for draining hydraulic fluid from the first hydraulic actuator, respectively, and a second hydraulic actuator and a second control valve for controlling the flow of hydraulic fluid from the pump to the second hydraulic actuator and for draining hydraulic fluid from the second hydraulic actuator, respectively. The hydraulic system further includes a first hydraulic circuit for providing an LS pressure for the first actuator and a second hydraulic circuit for providing an LS pressure for the second actuator. At least one of the first and second hydraulic circuits includes an offset valve for changing the LS pressure before providing the LS pressure to the pump.

Load sensing hydraulic system for a working machine

A working machine that includes an internal combustion engine, a generator, an energy storage and an electric motor for driving one or more wheels of the working machine is provided. The internal combustion engine is arranged to drive the generator and the generator is arranged to supply power to the electric motor via the energy storage. The working machine further includes an accelerator for controlling the electric motor, and a hydraulic pump for driving a hydraulic actuator. The hydraulic pump has a drive source different from the electric motor and the accelerator is arranged for controlling the speed of the hydraulic pump.

Working machine arranged with means to drive and control a hydraulic pump

A hydraulic system is provided for a working machine that includes a hydraulic cylinder for raising and lowering an implement. The hydraulic system includes a sensor for measuring a pressure in the hydraulic cylinder; and a control unit for controlling the movement of the hydraulic cylinder; wherein the control unit is configured to compare a pressure value measured by the sensor with a preset target pressure level range and to control the pressure in the hydraulic cylinder to be within the preset target pressure level range by adding or draining hydraulic fluid to/from a pressure side of the hydraulic cylinder for maintaining a substantially constant ground contact force between the implement and the ground.

Hydraulic system and method for controlling an implement of a working machine

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.

Method for controlling lowering of an implement of a working machine

A hydraulic system for a work machine including a first and a second hydraulic actuator, and a first and a second hydraulic machine for providing hydraulic fluid to at least one of the first and the second actuator via a first and a second priority valve, respectively. The first and second priority valves are controlled by a pressure drop &#x394;P over the inlet valve of the first actuator such that when &#x394;P is lower than a first threshold value T, a flow of hydraulic fluid is allowed only to the first actuator. The second priority valve allows a flow of hydraulic fluid to both the first and second actuator for a pressure drop higher than T. The first priority valve is further configured to allow a flow of hydraulic fluid to both of the first and second actuator for a pressure drop higher than a second threshold value Twhich is higher than T

Twin priority valve

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.

Arrangement for charging an accumulator

A system for a working machine is adapted for springing the movement of a load during transport and includes at least one hydraulic cylinder for operating the load, an accumulator, and a valve adapted to control a flow communication between the hydraulic cylinder and the accumulator. The system includes a first control valve arranged on a conduit connecting to the piston side of the hydraulic cylinder, a second control valve arranged on a conduit connecting to the piston rod side of the hydraulic cylinder, a first pressure sensor for detecting a load pressure of the hydraulic cylinder, a second pressure sensor for detecting a charge pressure of the accumulator, and a control unit adapted to receive signals with information about the pressures detected by the pressure sensors and to generate control signals corresponding to the detected pressures for controlling the springing function.

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Stora Sundby, Sweden

Bo Vigholm