EP3517790B1 - Working machine with hydraulics for energy recuperation - Google Patents

Working machine with hydraulics for energy recuperation Download PDF

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Publication number
EP3517790B1
EP3517790B1 EP18212578.1A EP18212578A EP3517790B1 EP 3517790 B1 EP3517790 B1 EP 3517790B1 EP 18212578 A EP18212578 A EP 18212578A EP 3517790 B1 EP3517790 B1 EP 3517790B1
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EP
European Patent Office
Prior art keywords
hydraulic
displacement unit
work machine
actuator
valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP18212578.1A
Other languages
German (de)
French (fr)
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EP3517790A1 (en
Inventor
Bernhard Meitinger
Manuel Wirthensohn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Liebherr Hydraulikbagger GmbH
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Liebherr Hydraulikbagger GmbH
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Publication of EP3517790A1 publication Critical patent/EP3517790A1/en
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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/14—Energy-recuperation means
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E02F3/435—Control of dipper or bucket position; Control of sequence of drive operations for dipper-arms, backhoes or the like
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • E02F9/2235—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps including an electronic controller
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2292—Systems with two or more pumps
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2296—Systems with a variable displacement pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20515—Electric motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20523—Internal combustion engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20569—Type of pump capable of working as pump and motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41509—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41572—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and an output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41581—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/426—Flow control characterised by the type of actuation electrically or electronically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6346—Electronic controllers using input signals representing a state of input means, e.g. joystick position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6651—Control of the prime mover, e.g. control of the output torque or rotational speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6652—Control of the pressure source, e.g. control of the swash plate angle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6658—Control using different modes, e.g. four-quadrant-operation, working mode and transportation mode
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7058—Rotary output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7135—Combinations of output members of different types, e.g. single-acting cylinders with rotary motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/75—Control of speed of the output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/76—Control of force or torque of the output member
    • F15B2211/761—Control of a negative load, i.e. of a load generating hydraulic energy

Definitions

  • the invention relates to a work machine with at least one hydraulic actuator for actuating a work device and a first displacement unit which is driven by a drive unit of the work machine and which feeds the hydraulic actuator with hydraulic medium from a hydraulic tank.
  • An example of a corresponding working machine is a hydraulic excavator, the extension arm of which can be actuated by means of a hydraulic linear actuator such as a piston-cylinder unit.
  • a hydraulic linear actuator such as a piston-cylinder unit.
  • a generic working machine is accordingly expanded by at least one second displacement unit driven by the drive unit, which in a working mode feeds the hydraulic actuator and further separate hydraulic consumers from a hydraulic tank with hydraulic medium.
  • the second displacement unit is driven by the hydraulic volume displaced by the at least one hydraulic actuator or a further hydraulic consumer. The kinetic energy generated in this way is fed back to the drive unit via the drive shaft, whereby the drive unit is relieved during the recuperation operation.
  • the additional, second displacement unit is therefore not only used for energy recovery, but also acts as an additional working pump in regular operation, which either supports the first displacement unit or, alternatively, supplies separate consumers with energy.
  • both the first displacement unit and the second displacement unit are part of an open hydraulic circuit, ie the hydraulic actuator is supplied with energy via an open hydraulic circuit. This will implement the solution according to the invention significantly easier compared to existing solutions of the prior art.
  • a control block is provided via which the outgoing pressure lines of the first and the second displacement unit can be connected to the hydraulic actuator and to the other consumers.
  • a corresponding control block comprises at least one control slide for the hydraulic actuator or further control slide for additional optional consumers.
  • a corresponding control slide can preferably provide several switching states, for example one switching position per direction of movement of the actuator and, if necessary, a neutral position for separating the pressure line from the actuator input. The same applies preferably to the at least one further control slide for optional consumers.
  • At least one first directional control valve is provided with at least two switching positions, which is arranged between the second displacement unit and the control block.
  • the connection between the second displacement unit and the control block can be released or interrupted via the at least two switching positions. Accordingly, a first switching position is provided which releases a volume flow from the second displacement unit to the control block, while a second switching position interrupts a volume flow between the second displacement unit and the control block.
  • At least one second directional valve is provided that switches or interrupts a direct connection between the at least one hydraulic actuator and the second displacement unit.
  • the second directional control valve is connected to the output of the hydraulic actuator, at which a corresponding volume flow can be generated for energy recuperation during load-related lowering. In the case of a piston-cylinder unit, this can preferably be the connection on the bottom.
  • the second directional control valve ideally comprises at least two switching positions, with a first switching position being one Volume flow from the hydraulic actuator to the second displacement unit switches, while the second switch position blocks a volume flow from the actuator to the second displacement unit.
  • At least one machine control of the working machine which controls the first and second directional control valves accordingly for the recuperation operation or the regular working operation.
  • the corresponding activation can take place as a function of the position of an operating lever provided for actuating the actuator.
  • This machine control can be designed as a separate machine control, but its integration into a machine control that is provided anyway is advisable.
  • the first directional valve for the recuperation operation is brought into its blocking position by the machine control while the second directional valve is switched to its flow position.
  • the valves are switched accordingly by the machine control when the operating lever is brought into a position for lowering due to the load. In this state, the volume flow generated by lowering the actuator can feed the second displacement unit, which operates as a hydraulic motor, via the second directional control valve.
  • the machine control switches the first directional control valve into its flow control, while the second directional valve remains in its blocking position.
  • the second displacement unit which works as a hydraulic pump, sucks in hydraulic medium from the tank and feeds the volume flow via the first directional valve into the pressure line of the working circuit or into the pressure line of the control block. The same can also apply to a neutral position of the operating lever.
  • the at least one hydraulic actuator is preferably a piston-cylinder unit, which is preferably used to actuate a boom of the work machine. At the Lowering the boom accordingly switches the work machine into recuperation mode, so that the potential energy released can be fed back into the overall system by means of the second displacement unit. It is also conceivable, however, if at least one hydraulic actuator is a rotary consumer, for example a hydraulic travel drive of the work machine.
  • the second displacement unit can be an adjustable pump motor.
  • An electrically controlled pump with a check valve in the suction is also conceivable. The latter would make the use of the aforementioned first directional control valve between the displacement pump and control block unnecessary.
  • the machine control of the work machine sets the swivel angle of the adjustable hydraulic motor or the electrically controlled pump in recuperation mode as a function of a desired target movement speed of the hydraulic actuator, in particular the piston-cylinder unit, i.e. depending on the desired lowering speed of the hydraulic actuator, preferably the extension arm.
  • the desired lowering speed can preferably be determined on the basis of the actual position of an operating lever for actuating the actuator.
  • the machine control is connected to the operating lever to determine its actual position.
  • the maximum volume flow caused by the actuator in recuperation mode can be set via the set swivel angle.
  • the swivel angle can take place as a function of the encoder position of an encoder for controlling the rotary drive and / or as a function of the rotational speed of the rotary drive detected by sensors.
  • At least one further hydraulic consumer is with hydraulic energy during the recuperation operation by the first displacement unit supplyable. Only the second displacement unit works in motor mode, the regular operation of the first displacement unit remains unaffected.
  • a throttle in particular a variable measuring orifice, preferably in the form of a proportional directional valve with an open and a blocking end position, is additionally introduced between the second directional valve and the second displacement unit.
  • the released speed of the second displacement unit can be controlled via the degree of opening of the throttle by throttling the volume flow generated by the actuator. In particular, this is intended to reduce or prevent an increase in the speed of the drive assembly due to the kinetic energy output of the second displacement unit.
  • At least one proportionally controllable bypass valve at the output of the second directional valve, the degree of which is increased by the machine control if the desired movement speed of the actuator cannot be achieved in recuperation mode due to the volume flow limitation of the second displacement unit, i.e. the required volume flow at the output of the actuator would exceed the maximum possible volume flow of the second displacement unit.
  • the bypass valve With the help of the bypass valve, the excess volume flow can be conducted via the bypass into the hydraulic tank, so that the desired movement speed of the actuator is achieved.
  • a linear actuator in the form of the piston-cylinder unit 80 which is used to actuate the excavator boom of the working machine according to the invention, can be seen here.
  • the required hydraulic pressure is provided by the main pump 20, which is driven via the central drive unit 10.
  • the pump 20 is designed as a variable displacement pump.
  • the hydraulic circuit is designed as an open hydraulic circuit, since the hydraulic pump 20 sucks in the necessary hydraulic medium from the tank and supplies the linear actuator 80 with hydraulic energy via the control block 90. Via the block 90, the feed pressure can optionally be fed to the base-side or rod-side connection of the actuator in order to control the actuation direction of the piston.
  • a second displacement unit 30 is mounted, which via the same output shaft of the drive unit 10 together with the first displacement unit 20 is driven by the drive unit 10.
  • This second displacement unit is designed as an adjustable pump motor, the swivel angle of which is set by the central machine control 60.
  • the displacement unit 30 is connected to the hydraulic tank and, in regular working operation, provides a corresponding volume flow at its outlet as a function of the set pivot angle.
  • This pressure line is connected to the control block 90 via a first directional valve 40, the output of the directional valve 40 being brought together with the pressure output line of the main pump 20.
  • the directional control valve 40 has two switching positions. In the first switching position, the valve is permeable in the direction of the control block 90, so that the output pressure of the hydraulic motor 30, together with the pressure line of the main pump 20, is applied to the pressure inlet of the control block 90. The valve locks in the second switching position. The switching position of the directional valve is actuated by the controller 60.
  • the displacement unit 30 is connected to the linear actuator 80 via the same connection by means of the directional control valve 50.
  • the valve inlet is connected to the bottom connection of the linear actuator, since there in recuperation mode, i.e. When lowering the excavator boom, a volume flow is generated by hydraulic oil escaping from the bottom.
  • the valve 50 also has two switching positions, one of which enables the flow from the actuator 80 to the hydraulic motor 30 and the second blocks the flow. This directional valve 50 is also activated via the central control unit 60.
  • Additional hydraulic consumers 100, 110 can be supplied with the necessary pressure level by pumps 20, 30 via control block 90.
  • the actuator 80 is operated via the operating lever 70.
  • the position of the operating lever is recognized by the control.
  • the controller 60 In the neutral position of the operating lever 70 or in its position for lifting the boom (hereinafter referred to as working mode), the controller 60 ensures that the valve 40 remains in its open position and the valve 50 remains in the blocking position.
  • the displacement unit 30 works as an additional working pump and the volume flow generated is made available via the valve 40 at the pressure inlet of the control block 90. Due to the blocking position of the valve 50, the bottom connection of the actuator is only connected to the control block 90.
  • further consumers 100, 110 can be supplied with oil by the working pumps 20, 30.
  • the controller 60 If the operating lever 70 is brought into the corresponding position for lowering the excavator boom, this is recognized by the controller 60 and the hydraulics are switched to recuperation mode.
  • the valve 40 is switched to its blocking position by the controller 60, whereby the volume flow from the second displacement unit 30 to the control block 90 is interrupted.
  • the controller 60 switches the second directional valve 50 into its flow position and the swivel angle of the hydraulic motor 30 is set to a negative swivel angle.
  • the hydraulic pressure on the bottom side of the actuator 80 can be output via the directional control valve 50 to the displacement unit operating as a motor, whereby it generates a torque that relieves the load on the drive shaft of the drive motor 10.
  • the specific pivoting angle of the pump motor 30 is determined by the controller 60 as a function of the actual deflection of the transmitter 70, because this is ultimately decisive for the lowering speed that can be achieved for the extension arm.
  • the other consumers 100, 110 can continue to be supplied with hydraulic oil by the working pump 20 in recuperation mode.
  • FIG. 2 shows details of the control block 90 for controlling the actuator 80 and further consumers 100 according to a first embodiment.
  • the other components correspond to the structure of the Figure 1 .
  • the common pressure line of the displacement units 20, 30 is connected to a first control slide 91 in the form of a proportional directional control valve. This comprises a total of three switch positions a, b and d.
  • the neutral position in which the valve blocks completely is marked with a.
  • the pressure line of the displacement units 20, 30 is connected to the bottom side of the actuator 80, the extending piston rod preferably leads to the lifting of the boom.
  • the pressure line is connected to the rod side of the actuator 80, the volume flow provided by the displacement units 20, 30 actively pushes the piston into the cylinder unit and the boom is "actively" lowered.
  • the valve 40 is brought into its blocking position so that no oil can flow from the displacer unit 30 to the control slide 91.
  • the control slide 91 remains in neutral position a and the valve 50 is opened.
  • the displacer unit 30 is set to a specific negative pivot angle as a function of the deflection of the transmitter 70, which specifies the lowering speed. This will lower the equipment at the desired speed.
  • oil is required on the rod side of the cylinder 80, which oil is made available from the tank via the suction valve 93 of the control block 90.
  • the displacement unit 30 generates a moment that is determined by the pressure that prevails in the cylinder base of the actuator 80 and the set pivot angle of the displacement unit 30. This moment relieves the drive unit 10.
  • the "active lowering" mode must be switched to.
  • the valve 40 is switched to its flow position, while the valve 50 goes into the blocking position.
  • Oil can now flow from the displacement unit 30 to the control slide 91, which is in position 91d.
  • the control slide 91 has to convey the oil from the pumps 20, 30 to the rod side of the lifting cylinder 80.
  • the oil from the bottom must flow back to the tank via the control slide 91, which Valve 50 remains blocked.
  • the displacement unit 30 acts as a second working pump or as a pump for additional consumers 100.
  • the valve 40 For regular work, i.e. the valve 40 is opened to raise the boom, and oil can flow from the displacement unit 30 to the control slide 91.
  • the valve 50 remains closed.
  • the displacement unit 30 is a second working pump or a pump for additional consumers 100.
  • a modified embodiment of the hydraulics is Figure 3 refer to. Identical components are provided with identical reference symbols.
  • a variable measuring orifice 120 is additionally inserted downstream after the second directional control valve 50, ie between the valve 50 and the second displacement unit 30.
  • This proportionally controllable directional valve 120 takes an opening degree between an end position with full bidirectional flow and a second end position in which the valve 120 blocks completely.
  • the current degree of opening of the throttle 120 is also set by the controller 60.
  • the throttle 120 is intended, for example, to prevent the motor 10 from being accelerated by the torque output by the displacement unit 30. A reduction in the volume flow is necessary for this, which is achieved by reducing the cross section in the valve 120 accordingly.
  • FIG. 2 Another change compared to the Figure 2 comprises the control slide 91 of the control block 90 of Figure 3 an additional switch position 91c. If the volume flow due to the required setpoint speed of the actuator 80 is greater than the possible volume flow through the displacement unit 30, the control slide 91 is switched to the position 91c.
  • an additional bypass valve 130 can be arranged downstream on the directional control valve 50, as shown in FIG Figure 4 is shown.
  • This proportionally controllable directional valve 130 switches, depending on the degree of opening, a bypass of the volume flow generated in recuperation operation into the hydraulic tank. If the volume flow is greater than the maximum possible volume flow of the displacement unit 30 due to the required setpoint speed of the actuator 80, the bypass valve 130 is opened to the extent that the required lowering speed can be achieved.
  • the presented exemplary embodiments of the hydraulic circuits of Figures 1 to 4 can not only be used for energy recovery in linear drives, but the functional principle presented can also be used in rotary drives. This is shown using the example of Figure 5 .
  • the hydraulic structure essentially corresponds to the hydraulic circuit diagram of Figure 4 , same parts and components were also used in Figure 5 with the same reference numerals we in the Figures 1 to 4 designated. For the relevant description, reference is therefore made to the preceding description of the figures.
  • a rotary drive 110 is controlled by means of the control block in addition to the linear actuators.
  • the rotary drive can, for example, be a travel drive for the work machine.
  • this has been supplemented, among other things, by the additional proportional control valves 95, 96, which provide the necessary hydraulic supply to the drive 110.
  • the rotary consumer 110 is braked, energy is to be recovered in order to deliver a torque to the internal combustion engine 10 by means of the displacement unit 30.
  • valve 40 In the regular working operation of the consumer 110, the valve 40 is switched to the open position, whereby oil can flow from the displacement unit 30 to the control slide 90.
  • the valve 50 must be closed.
  • the valves 95, 96 of the control block 90 give depending on the position of the transmitter now provided 114 free an opening cross section, whereby the required speed and / or rotational speed of the motor 110 can be set.
  • the direction of rotation can be specified by the switching position of the valves 95, 96.
  • the rotary drive 110 can be accelerated or the current speed of rotation can be maintained.
  • the valve 40 In the braking or recuperation operation of the drive 110, the valve 40 is switched to the closed position, so no oil can flow from the displacement unit 30 to the control block 90.
  • the valve 50 is opened. If the motor 110 rotates clockwise, the valve 95 must be in the lower regulating position.
  • the valve 96 is in the closed position.
  • the additional directional valve 112 is located on the outlet side of the motor 110 and must be in the open switch position, as a result of which the draining oil can be conducted via the displacement unit 30 into the tank.
  • the displacer unit 30 is set to a specific negative swivel angle which is specified by the ECU 60.
  • the ECU 60 calculates the value of the swivel angle from the drive speed specified by the sensor 111 and the detected position of the transmitter 114.
  • the displacement unit 30 generates a torque that results from the hydraulic pressure generated by the drive 110 during the braking process and the set pivot angle of the displacement unit 30, and outputs this to the internal combustion engine 10. Meanwhile, the other consumers 80, 100 can be supplied with oil by the working pump 20.
  • a closed-loop control can take place.
  • the working pump 20 and one of the valves 95 or 96 specify the speed of the motor 110 as a function of the encoder 114.
  • one of the valves 112, 113 which is on the outlet side of the motor 110, must always be in the open position. The draining oil thus flows back via the valve 120 and via the displacement unit 30.
  • valves 120 and 130 corresponds to the function that has already been described using the exemplary embodiment of FIG Figure 4 was explained. If the rotary consumer 110 has a brake valve (not shown here), then this must of course also be controllable by the ECU 60. The integration of the rotary drive could of course also, with a corresponding expansion of the control block 90, also in one of the exemplary embodiments according to FIGS Figures 1 to 3 respectively.
  • recuperation system described here (in particular the exemplary embodiments according to FIGS Figures 1 to 5 ) can be implemented not only for the LS system shown here, but also for systems with electrical pump control.
  • Fig. 5 a mixed system of LS valves and separate control edge valves is shown. If the hydraulic system is designed as a pure system with separate control edge valves (without pressure compensators), an electric pump control is absolutely necessary. Such a system makes recuperation - as described here - considerably easier, since in the case of recuperation the valve in the outlet can be closed and the valve in the inlet can only be opened when required.
  • the displacement unit 30 could be designed in the form of an electrically controlled pump with a check valve in the suction.
  • the valve 40 could be omitted, which is particularly evident in FIG Figure 6 is shown.
  • the valve 50 is then directly connected to the actual suction side of the pump 30, which acts as a pressure input in recuperation mode.

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Description

Die Erfindung betrifft eine Arbeitsmaschine mit wenigstens einem hydraulischen Aktor zur Betätigung eines Arbeitsgerätes und einer durch einen Antriebsaggregat der Arbeitsmaschine angetriebenen ersten Verdrängereinheit, die den hydraulischen Aktor aus einem Hydrauliktank mit Hydraulikmedium speist.The invention relates to a work machine with at least one hydraulic actuator for actuating a work device and a first displacement unit which is driven by a drive unit of the work machine and which feeds the hydraulic actuator with hydraulic medium from a hydraulic tank.

Ein Beispiel für eine entsprechende Arbeitsmaschine ist ein hydraulischer Bagger, dessen Auslegerarm mittels eines hydraulischen Linearaktors wie einer Kolbenzylindereinheit betätigbar ist. Üblicherweise muss für das Absenken des Auslegers keine hydraulische Energie aufgebracht werden, da sich der Ausleger lastbedingt absenken kann. In diesem Zusammenhang ist es wünschenswert, die dabei frei werdende potentielle Energie in das System zurückzuspeisen.An example of a corresponding working machine is a hydraulic excavator, the extension arm of which can be actuated by means of a hydraulic linear actuator such as a piston-cylinder unit. Usually, no hydraulic energy has to be applied to lower the boom, since the boom can lower due to the load. In this context it is desirable to feed the potential energy that is released back into the system.

Aus dem Stand der Technik sind bisher diverse Lösungsansätze für die Energierekuperation bekannt. Ein Teil dieser Lösungsansätze setzt auf einen geschlossenen Hydraulikkreis für die Energierekuperation, was jedoch vergleichsweise teuer und komplex ist. Gemäß alternativen Lösungen wird bei einer Senkbewegung ein Verdränger mit dem zurückgespeisten Hydraulikmedium gefördert. Das dadurch erzeugte Drehmoment treibt einen angeschlossenen Generator zur Erzeugung elektrischer Energie an. Die dazu benötigte Elektrik macht auch diese Lösung vergleichsweise aufwändig und teuer, insbesondere da die zurückgewonnene Energie zunächst zwischengespeichert werden muss.Various solutions for energy recuperation are known from the prior art. Some of these approaches rely on a closed hydraulic circuit for energy recuperation, which, however, is comparatively expensive and complex. According to alternative solutions, a displacer is conveyed with the returned hydraulic medium during a lowering movement. The resulting Torque drives a connected generator to generate electrical energy. The electrical system required for this also makes this solution comparatively complex and expensive, especially since the recovered energy must first be temporarily stored.

Eine bekannte Arbeitsmaschine ist von der WO 2015/130518 A1 offenbart.One known working machine is from the WO 2015/130518 A1 disclosed.

Gesucht wird daher nach einer alternativen Lösung, die vergleichsweise einfach ist. Gelöst wird diese Aufgabe durch eine Arbeitsmaschine gemäß den Merkmalen des Anspruchs 1. Vorteilhafte Ausgestaltungen der Arbeitsmaschine sind Gegenstand der abhängigen Ansprüche.We are therefore looking for an alternative solution that is comparatively simple. This object is achieved by a work machine according to the features of claim 1. Advantageous configurations of the work machine are the subject of the dependent claims.

Erfindungsgemäß wird demzufolge eine gattungsgemäße Arbeitsmaschine um wenigstens eine durch das Antriebsaggregat angetriebene zweite Verdrängereinheit erweitert, die in einem Arbeitsbetrieb den hydraulischen Aktor und weitere separate hydraulische Verbraucher aus einem Hydrauliktank mit Hydraulikmedium speist. Während eines Rekuperationsbetriebs wird die zweite Verdrängereinheit durch das von dem wenigstens einen hydraulischen Aktor oder einem weiteren hydraulischen Verbraucher verdrängte Hydraulikvolumen angetrieben. Die hierdurch erzeugte kinetische Energie wird über die Antriebswelle an das Antriebsaggregat zurückgespeist, wodurch das Antriebsaggregat während des Rekuperationsbetriebes entlastet wird.According to the invention, a generic working machine is accordingly expanded by at least one second displacement unit driven by the drive unit, which in a working mode feeds the hydraulic actuator and further separate hydraulic consumers from a hydraulic tank with hydraulic medium. During a recuperation operation, the second displacement unit is driven by the hydraulic volume displaced by the at least one hydraulic actuator or a further hydraulic consumer. The kinetic energy generated in this way is fed back to the drive unit via the drive shaft, whereby the drive unit is relieved during the recuperation operation.

Die zusätzliche zweite Verdrängereinheit dient demzufolge nicht nur für die Energierückgewinnung, sondern agiert im regulären Arbeitsbetrieb als zusätzliche Arbeitspumpe, die entweder die erste Verdrängereinheit unterstützt oder alternativ separate Verbraucher mit Energie versorgt.The additional, second displacement unit is therefore not only used for energy recovery, but also acts as an additional working pump in regular operation, which either supports the first displacement unit or, alternatively, supplies separate consumers with energy.

Bezeichnend für die erfindungsgemäße Lösung ist, dass sowohl die erste Verdrängereinheit als auch die zweite Verdrängereinheit Teil eines offenen Hydraulikreislaufes sind, d.h. der hydraulische Aktor wird über einen offenen Hydraulikkreislauf mit Energie versorgt. Dadurch wird die Umsetzung der erfindungsgemäßen Lösung deutlich einfacher im Vergleich zu bestehenden Lösungen des Standes der Technik.It is characteristic of the solution according to the invention that both the first displacement unit and the second displacement unit are part of an open hydraulic circuit, ie the hydraulic actuator is supplied with energy via an open hydraulic circuit. This will implement the solution according to the invention significantly easier compared to existing solutions of the prior art.

Gemäß der Erfindung ist ein Steuerblock vorgesehen, über den die ausgehenden Druckleitungen der ersten als auch der zweiten Verdrängereinheit mit dem hydraulischen Aktor und mit den weiteren Verbrauchern verbindbar sind. Ein entsprechender Steuerblock umfasst zumindest wenigstens einen Steuerschieber für den hydraulischen Aktor bzw. weitere Steuerschieber für zusätzliche optionale Verbraucher. Ein entsprechender Steuerschieber kann vorzugsweise mehrere Schaltzustände vorsehen, bspw. jeweils eine Schaltstellung pro Bewegungsrichtung des Aktors und gegebenenfalls eine Neutralstellung für die Trennung der Druckleitung vom Aktoreingang. Selbiges gilt vorzugsweise für den wenigstens einen weiteren Steuerschieber für optionale Verbraucher.According to the invention, a control block is provided via which the outgoing pressure lines of the first and the second displacement unit can be connected to the hydraulic actuator and to the other consumers. A corresponding control block comprises at least one control slide for the hydraulic actuator or further control slide for additional optional consumers. A corresponding control slide can preferably provide several switching states, for example one switching position per direction of movement of the actuator and, if necessary, a neutral position for separating the pressure line from the actuator input. The same applies preferably to the at least one further control slide for optional consumers.

Gemäß der Erfindung ist wenigstens ein erstes Wegeventil, mit wenigstens zwei Schaltstellungen vorgesehen, das zwischen zweiter Verdrängereinheit und Steuerblock angeordnet ist. Über die wenigstens zwei Schaltstellungen kann die Verbindung zwischen zweiter Verdrängereinheit und Steuerblock freigegeben bzw. unterbrochen werden. Demzufolge ist also eine erste Schaltstellung vorgesehen, die einen Volumenstrom von der zweiten Verdrängereinheit zum Steuerblock freigibt, während eine zweite Schaltstellung einen Volumenstrom zwischen zweiter Verdrängereinheit und Steuerblock unterbricht.According to the invention, at least one first directional control valve is provided with at least two switching positions, which is arranged between the second displacement unit and the control block. The connection between the second displacement unit and the control block can be released or interrupted via the at least two switching positions. Accordingly, a first switching position is provided which releases a volume flow from the second displacement unit to the control block, while a second switching position interrupts a volume flow between the second displacement unit and the control block.

Zusätzlich ist wenigstens ein zweites Wegeventil, vorgesehen, dass eine direkte Verbindung zwischen dem wenigstens einem hydraulischen Aktor und der zweiten Verdrängereinheit schaltet bzw. unterbricht. Insbesondere ist das zweite Wegeventil mit dem Ausgang des hydraulischen Aktors verbunden, an dem beim lastbedingten Absenken für die Energierekuperation ein entsprechender Volumenstrom erzeugbar ist. Bei einer Kolben-Zylindereinheit kann dies bevorzugt der bodenseitige Anschluss sein. Das zweite Wegeventil umfasst idealerweise wenigstens zwei Schaltstellungen, wobei eine erste Schaltstellung einen Volumenstrom vom hydraulischen Aktor zur zweiten Verdrängereinheit schaltet, während die zweite Schaltstellung einen Volumenstrom vom Aktor zur zweiten Verdrängereinheit sperrt.In addition, at least one second directional valve is provided that switches or interrupts a direct connection between the at least one hydraulic actuator and the second displacement unit. In particular, the second directional control valve is connected to the output of the hydraulic actuator, at which a corresponding volume flow can be generated for energy recuperation during load-related lowering. In the case of a piston-cylinder unit, this can preferably be the connection on the bottom. The second directional control valve ideally comprises at least two switching positions, with a first switching position being one Volume flow from the hydraulic actuator to the second displacement unit switches, while the second switch position blocks a volume flow from the actuator to the second displacement unit.

Darüber hinaus ist es zweckmäßig, wenn wenigstens eine Maschinensteuerung der Arbeitsmaschine vorgesehen ist, die das erste und zweite Wegeventil entsprechend für den Rekuperationsbetrieb bzw. den regulären Arbeitsbetrieb ansteuert. Die entsprechende Ansteuerung kann in Abhängigkeit der Stellung eines für die Aktorbetätigung vorgesehenen Bedienhebels erfolgen. Diese Maschinensteuerung kann als separate Maschinensteuerung ausgestaltet sein, es bietet sich jedoch deren Integration in eine ohnehin vorgesehene Maschinensteuerung an.In addition, it is expedient if at least one machine control of the working machine is provided, which controls the first and second directional control valves accordingly for the recuperation operation or the regular working operation. The corresponding activation can take place as a function of the position of an operating lever provided for actuating the actuator. This machine control can be designed as a separate machine control, but its integration into a machine control that is provided anyway is advisable.

Bevorzugt ist es, wenn das erste Wegeventil für den Rekuperationsbetrieb von der Maschinensteuerung in seine Sperrstellung gebracht wird, während das zweite Wegeventil in seine Durchflussstellung geschaltet wird. Insbesondere werden die Ventile entsprechend durch die Maschinensteuerung geschaltet, wenn der Bedienhebel in eine Stellung zum lastbedingten Absenken verbracht wird. In diesem Zustand kann der durch das Absenken des Aktors erzeugte Volumenstrom über das zweite Wegeventil die als Hydraulikmotor arbeitende zweite Verdrängereinheit speisen.It is preferred if the first directional valve for the recuperation operation is brought into its blocking position by the machine control while the second directional valve is switched to its flow position. In particular, the valves are switched accordingly by the machine control when the operating lever is brought into a position for lowering due to the load. In this state, the volume flow generated by lowering the actuator can feed the second displacement unit, which operates as a hydraulic motor, via the second directional control valve.

Für den regulären Arbeitsbetrieb, vorzugsweise sobald mittels des Bedienhebels eine der lastbedingten Senkbewegung gegenläufige Bewegung ausgelöst wird, schaltet die Maschinensteuerung das erste Wegeventil in seine Durchflusssteuerung, während das zweite Wegeventil in seiner Sperrstellung verbleibt. Die als Hydraulikpumpe arbeitende zweite Verdrängereinheit saugt in diesem Fall Hydraulikmedium aus dem Tank an und speist den Volumenstrom über das erste Wegeventil in die Druckleitung des Arbeitskreises bzw. in die Druckleitung des Steuerblocks ein. Gleiches kann auch für eine Neutralstellung des Bedienhebels gelten.For regular operation, preferably as soon as a movement in the opposite direction to the load-related lowering movement is triggered by means of the operating lever, the machine control switches the first directional control valve into its flow control, while the second directional valve remains in its blocking position. In this case, the second displacement unit, which works as a hydraulic pump, sucks in hydraulic medium from the tank and feeds the volume flow via the first directional valve into the pressure line of the working circuit or into the pressure line of the control block. The same can also apply to a neutral position of the operating lever.

Bevorzugt ist der wenigstens eine hydraulische Aktor eine Kolbenzylindereinheit, die vorzugsweise zur Betätigung eines Auslegers der Arbeitsmaschine dient. Beim Absenken des Auslegers schaltet die Arbeitsmaschine demzufolge in den Rekuperationsbetrieb, sodass die abgegebene potenzielle Energie mittels der zweiten Verdrängereinheit in das Gesamtsystem zurückgespeist werden kann. Denkbar ist es jedoch ebenfalls, wenn wenigstens ein hydraulischer Aktor ein rotatorischer Verbraucher ist, bspw. ein hydraulischer Fahrantrieb der Arbeitsmaschine.The at least one hydraulic actuator is preferably a piston-cylinder unit, which is preferably used to actuate a boom of the work machine. At the Lowering the boom accordingly switches the work machine into recuperation mode, so that the potential energy released can be fed back into the overall system by means of the second displacement unit. It is also conceivable, however, if at least one hydraulic actuator is a rotary consumer, for example a hydraulic travel drive of the work machine.

Die zweite Verdrängereinheit kann ein verstellbarer Pumpenmotor sein. Denkbar ist auch eine elektrisch geregelte Pumpe mit Rückschlagventil in der Ansaugung. Letztere würde den Einsatz des vorgenannten ersten Wegeventils zwischen Verdrängerpumpe und Steuerblock unnötig machen.The second displacement unit can be an adjustable pump motor. An electrically controlled pump with a check valve in the suction is also conceivable. The latter would make the use of the aforementioned first directional control valve between the displacement pump and control block unnecessary.

Bei Verwendung des verstellbaren Hydromotors bzw. der elektrisch geregelten Pumpe ist vorgesehen, dass die Maschinensteuerung der Arbeitsmaschine den Schwenkwinkel des verstellbaren Hydromotors bzw. der elektrisch geregelten Pumpe im Rekuperationsbetrieb in Abhängigkeit einer gewünschten Soll-Bewegungsgeschwindigkeit des hydraulischen Aktors, insbesondere der Kolbenzylindereinheit einstellt, d.h. in Abhängigkeit der gewünschten Senkgeschwindigkeit des Hydraulikaktors, bevorzugt des Auslegerarms. Die gewünschte Senkgeschwindigkeit kann bevorzugt anhand der Ist-Stellung eines Bedienhebels zur Betätigung des Aktors ermittelt werden. Demzufolge ist die Maschinensteuerung mit dem Bedienhebel zur Ermittlung deren Ist-Stellung verbunden. Über den eingestellten Schwenkwinkel lässt sich der maximale, durch den Aktor im Rekuperationsbetrieb hervorgerufene Volumenstrom einstellen.When using the adjustable hydraulic motor or the electrically controlled pump, it is provided that the machine control of the work machine sets the swivel angle of the adjustable hydraulic motor or the electrically controlled pump in recuperation mode as a function of a desired target movement speed of the hydraulic actuator, in particular the piston-cylinder unit, i.e. depending on the desired lowering speed of the hydraulic actuator, preferably the extension arm. The desired lowering speed can preferably be determined on the basis of the actual position of an operating lever for actuating the actuator. As a result, the machine control is connected to the operating lever to determine its actual position. The maximum volume flow caused by the actuator in recuperation mode can be set via the set swivel angle.

Ist der hydraulische Aktor ein Rotationsantrieb und erfolgt die Rekuperation im Bremsbetrieb des Rotationsantriebes, so kann der Schwenkwinkel in Abhängigkeit der Geberstellung eines Gebers zur Steuerung des Rotationsantriebs und/oder in Abhängigkeit der sensorisch erfassten Drehzahl des Rotationsantriebes erfolgen.If the hydraulic actuator is a rotary drive and the recuperation takes place in braking mode of the rotary drive, the swivel angle can take place as a function of the encoder position of an encoder for controlling the rotary drive and / or as a function of the rotational speed of the rotary drive detected by sensors.

Idealerweise ist wenigstens ein weiterer hydraulischer Verbraucher während des Rekuperationsbetriebes durch die erste Verdrängereinheit mit hydraulischer Energie versorgbar. Es arbeitet lediglich die zweite Verdrängereinheit im Motorbetrieb, der reguläre Arbeitsbetrieb der ersten Verdrängereinheit bleibt hiervon unberührt.Ideally, at least one further hydraulic consumer is with hydraulic energy during the recuperation operation by the first displacement unit supplyable. Only the second displacement unit works in motor mode, the regular operation of the first displacement unit remains unaffected.

Es kann vorgesehen sein, dass zwischen dem zweiten Wegeventil und der zweiten Verdrängereinheit zusätzlich eine Drossel, insbesondere eine variable Messblende, vorzugsweise in Form eines Proportionalwegeventils mit einer geöffneten und einer sperrenden Endstellung, eingebracht ist. Über den Öffnungsgrad der Drossel kann die ausgelöste Drehzahl der zweiten Verdrängereinheit durch Drosselung des durch den Aktor erzeugten Volumenstroms gesteuert werden. Insbesondere soll hierdurch eine Drehzahlerhöhung des Antriebsaggregates durch die abgegebene kinetische Energie der zweiten Verdrängereinheit reduziert bzw. unterbunden werden.It can be provided that a throttle, in particular a variable measuring orifice, preferably in the form of a proportional directional valve with an open and a blocking end position, is additionally introduced between the second directional valve and the second displacement unit. The released speed of the second displacement unit can be controlled via the degree of opening of the throttle by throttling the volume flow generated by the actuator. In particular, this is intended to reduce or prevent an increase in the speed of the drive assembly due to the kinetic energy output of the second displacement unit.

Ferner ist es möglich, am Ausgang des zweiten Wegeventils wenigstens ein proportional steuerbares Bypassventil anzuordnen, dessen Öffnungsgrad durch die Maschinensteuerung erhöht wird, falls die gewünschte Bewegungsgeschwindigkeit des Aktors im Rekuperationsbetrieb aufgrund der Volumenstrombegrenzung der zweiten Verdrängereinheit nicht erreicht werden kann, d.h. der benötigte Volumenstrom am Ausgang des Aktors würde den maximal möglichen Volumenstrom der zweiten Verdrängereinheit übersteigen. Mit Hilfe des Bypass-Ventils kann der überschüssige Volumenstrom über den Bypass in den Hydrauliktank geleitet werden, so dass ein Erreichen der gewünschten Bewegungsgeschwindigkeit des Aktors sichergestellt ist.Furthermore, it is possible to arrange at least one proportionally controllable bypass valve at the output of the second directional valve, the degree of which is increased by the machine control if the desired movement speed of the actuator cannot be achieved in recuperation mode due to the volume flow limitation of the second displacement unit, i.e. the required volume flow at the output of the actuator would exceed the maximum possible volume flow of the second displacement unit. With the help of the bypass valve, the excess volume flow can be conducted via the bypass into the hydraulic tank, so that the desired movement speed of the actuator is achieved.

Weitere Vorteile und Eigenschaften der Erfindung sollen im Folgenden anhand eines in den Figuren dargestellten Ausführungsbeispiels näher erläutert werden. Es zeigen:

Fig. 1:
ein hydraulisches Schaltbild zur Verdeutlichung der erfindungsgemäßen Funktionsweise der Arbeitsmaschine in Form eines Hydraulikbaggers;
Fig. 2:
ein hydraulisches Schaltbild für ein erstes Ausführungsbeispiel der vorliegenden Erfindung;
Fig. 3:
ein weiteres Hydraulikschaltbild für ein zweites Ausführungsbeispiel,
Fig. 4:
ein weiteres Hydraulikschaltbild für ein drittes Ausführungsbeispiel,
Fig. 5:
ein Hydraulikschaltbild einer Modifikation des dritten Ausführungsbeispiels gemäß Fig. 4 und
Fig. 6:
ein hydraulisches Schaltbild zur Verdeutlichung einer nicht zur Erfindung gehörenden Abwandlung aller Ausführungsbeispiele gemäß den Figuren 1 bis 5.
Further advantages and properties of the invention are to be explained in more detail below with reference to an exemplary embodiment shown in the figures. Show it:
Fig. 1:
a hydraulic circuit diagram to illustrate the operation of the machine according to the invention in the form of a hydraulic excavator;
Fig. 2:
a hydraulic circuit diagram for a first embodiment of the present invention;
Fig. 3:
another hydraulic circuit diagram for a second embodiment,
Fig. 4:
another hydraulic circuit diagram for a third embodiment,
Fig. 5:
a hydraulic circuit diagram of a modification of the third embodiment according to Fig. 4 and
Fig. 6:
a hydraulic circuit diagram to illustrate a non-part of the invention modification of all the embodiments according to Figures 1 to 5 .

Die grundlegende Funktionsweise der vorliegenden Erfindung soll anhand des skizzierten Hydraulikschaltbildes der Figur 1 erläutert werden. Hierbei ist der Steuerblock 90 für die Ansteuerung des hydraulischen Aktors 80 nicht weiter dargestellt, sondern davon unabhängig soll der Kerngedanke der Erfindung anhand des Schaltbildes erläutert werden.The basic mode of operation of the present invention will be based on the sketched hydraulic circuit diagram of Figure 1 explained. Here, the control block 90 for the control of the hydraulic actuator 80 is not shown in any more detail, but the core concept of the invention is to be explained independently of this with the aid of the circuit diagram.

Ersichtlich ist hier ein Linearaktor in Form der Kolbenzylindereinheit 80, der zur Betätigung des Baggerauslegers der erfindungsgemäßen Arbeitsmaschine dient. Der erforderliche Hydraulikdruck wird durch die Hauptpumpe 20 bereitgestellt, die über das zentrale Antriebsaggregat 10 angetrieben wird. Die Pumpe 20 ist als Verstellpumpe ausgeführt. Der Hydraulikkreis ist als offener Hydraulikkreislauf ausgestaltet, da die Hydraulikpumpe 20 das notwendige Hydraulikmedium aus dem Tank ansaugt und über den Steuerblock 90 den Linearaktor 80 mit hydraulischer Energie versorgt. Über den Block 90 kann der Speisedruck wahlweise dem bodenseitigen oder stangenseitigen Anschluss des Aktors zugeführt werden, um die Betätigungsrichtung des Kolbens zu steuern.A linear actuator in the form of the piston-cylinder unit 80, which is used to actuate the excavator boom of the working machine according to the invention, can be seen here. The required hydraulic pressure is provided by the main pump 20, which is driven via the central drive unit 10. The pump 20 is designed as a variable displacement pump. The hydraulic circuit is designed as an open hydraulic circuit, since the hydraulic pump 20 sucks in the necessary hydraulic medium from the tank and supplies the linear actuator 80 with hydraulic energy via the control block 90. Via the block 90, the feed pressure can optionally be fed to the base-side or rod-side connection of the actuator in order to control the actuation direction of the piston.

Erfindungsgemäß ist eine zweite Verdrängereinheit 30 montiert, die über dieselbe Ausgangswelle des Antriebsaggregats 10 gemeinsam der mit ersten Verdrängereinheit 20 durch das Antriebsaggregat 10 angetrieben wird. Diese zweite Verdrängereinheit ist als verstellbarer Pumpenmotor ausgestaltet, dessen Schwenkwinkel von der zentralen Maschinensteuerung 60 eingestellt wird. Die Verdrängereinheit 30 ist zum einen mit dem Hydrauliktank verbunden und stellt im regulären Arbeitsbetrieb in Abhängigkeit des eingestellten Schwenkwinkels einen entsprechenden Volumenstrom an ihrem Ausgang zur Verfügung. Diese Druckleitung steht über ein erstes Wegeventil 40 mit dem Steuerblock 90 in Verbindung, wobei der Ausgang des Wegeventils 40 mit der Druckausgangsleitung der Hauptpumpe 20 zusammengeführt wird.According to the invention, a second displacement unit 30 is mounted, which via the same output shaft of the drive unit 10 together with the first displacement unit 20 is driven by the drive unit 10. This second displacement unit is designed as an adjustable pump motor, the swivel angle of which is set by the central machine control 60. On the one hand, the displacement unit 30 is connected to the hydraulic tank and, in regular working operation, provides a corresponding volume flow at its outlet as a function of the set pivot angle. This pressure line is connected to the control block 90 via a first directional valve 40, the output of the directional valve 40 being brought together with the pressure output line of the main pump 20.

Das Wegeventil 40 umfasst zwei Schaltstellungen. In der ersten Schaltstellung ist das Ventil in Richtung des Steuerblockes 90 durchlässig, so dass der Ausgangsdruck des Hydromotors 30 zusammen mit der Druckleitung der Hauptpumpe 20 am Druckeingang des Steuerblockes 90 anliegt. In der zweiten Schaltstellung sperrt das Ventil. Die Schaltstellung des Wegeventils wird durch die Steuerung 60 betätigt.The directional control valve 40 has two switching positions. In the first switching position, the valve is permeable in the direction of the control block 90, so that the output pressure of the hydraulic motor 30, together with the pressure line of the main pump 20, is applied to the pressure inlet of the control block 90. The valve locks in the second switching position. The switching position of the directional valve is actuated by the controller 60.

Darüber hinaus steht die Verdrängereinheit 30 über denselben Anschluss mittels des Wegeventils 50 mit dem Linearaktor 80 in Verbindung. Im gezeigten Ausführungsbeispiel ist der Ventileingang mit dem bodenseitigen Anschluss des Linearaktors verbunden, da dort im Rekuperationsbetrieb, d.h. beim Absenken des Baggerauslegers, ein Volumenstrom durch bodenseitig austretendes Hydrauliköl erzeugt wird.In addition, the displacement unit 30 is connected to the linear actuator 80 via the same connection by means of the directional control valve 50. In the embodiment shown, the valve inlet is connected to the bottom connection of the linear actuator, since there in recuperation mode, i.e. When lowering the excavator boom, a volume flow is generated by hydraulic oil escaping from the bottom.

Das Ventil 50 umfasst ebenfalls zwei Schaltstellungen, von denen eine den Durchfluss vom Aktor 80 zum Hydromotor 30 freigibt und die zweite den Durchfluss sperrt. Auch dieses Wegeventil 50 wird über die zentrale Steuereinheit 60 angesteuert.The valve 50 also has two switching positions, one of which enables the flow from the actuator 80 to the hydraulic motor 30 and the second blocks the flow. This directional valve 50 is also activated via the central control unit 60.

Über den Steuerblock 90 lassen sich weitere hydraulische Verbraucher 100, 110 mit dem notwendigen Druckniveau durch die Pumpen 20, 30 versorgen. Über den Bedienhebel 70 wird der Aktor 80 bedient.Additional hydraulic consumers 100, 110 can be supplied with the necessary pressure level by pumps 20, 30 via control block 90. The actuator 80 is operated via the operating lever 70.

Die Stellung des Bedienhebels wird von der Steuerung erkannt. In der Neutralstellung des Bedienhebels 70 bzw. in seiner Stellung zum Anheben des Auslegers (nachfolgend Arbeitsbetrieb genannt) sorgt die Steuerung 60 dafür, dass das Ventil 40 in seiner Durchlassstellung und das Ventil 50 in der Sperrstellung verbleibt. Die Verdrängereinheit 30 arbeitet in diesem Fall als zusätzliche Arbeitspumpe und der erzeugte Volumenstrom wird über das Ventil 40 am Druckeingang des Steuerblocks 90 bereitgestellt. Aufgrund der Sperrstellung des Ventils 50 ist der bodenseitige Anschluss des Aktors nur mit dem Steuerblock 90 verbunden. Neben dem Aktor 80 können weitere Verbraucher 100, 110 von den Arbeitspumpen 20, 30 mit Öl versorgt werden.The position of the operating lever is recognized by the control. In the neutral position of the operating lever 70 or in its position for lifting the boom (hereinafter referred to as working mode), the controller 60 ensures that the valve 40 remains in its open position and the valve 50 remains in the blocking position. In this case, the displacement unit 30 works as an additional working pump and the volume flow generated is made available via the valve 40 at the pressure inlet of the control block 90. Due to the blocking position of the valve 50, the bottom connection of the actuator is only connected to the control block 90. In addition to the actuator 80, further consumers 100, 110 can be supplied with oil by the working pumps 20, 30.

Wird der Bedienhebel 70 in die entsprechende Stellung zum Absenken des Baggerauslegers verbracht, so wird dies durch die Steuerung 60 erkannt und die Hydraulik in den Rekuperationsbetrieb geschaltet. Dazu wird das Ventil 40 von der Steuerung 60 in seine Sperrstellung geschaltet, wodurch der Volumenstrom von der zweiten Verdrängereinheit 30 zum Steuerblock 90 unterbrochen wird. Gleichzeitig schaltet die Steuerung 60 das zweite Wegeventil 50 in seine Durchflussstellung und der Schwenkwinkel des Hydromotors 30 wird auf einen negativen Schwenkwinkel eingestellt. Hierdurch kann der Hydraulikdruck der Bodenseite des Aktors 80 über das Wegeventil 50 an die als Motor arbeitende Verdrängereinheit abgegeben werden, wodurch diese ein Drehmoment erzeugt, das die Antriebswelle des Antriebsmotors 10 entlastet.If the operating lever 70 is brought into the corresponding position for lowering the excavator boom, this is recognized by the controller 60 and the hydraulics are switched to recuperation mode. For this purpose, the valve 40 is switched to its blocking position by the controller 60, whereby the volume flow from the second displacement unit 30 to the control block 90 is interrupted. At the same time, the controller 60 switches the second directional valve 50 into its flow position and the swivel angle of the hydraulic motor 30 is set to a negative swivel angle. As a result, the hydraulic pressure on the bottom side of the actuator 80 can be output via the directional control valve 50 to the displacement unit operating as a motor, whereby it generates a torque that relieves the load on the drive shaft of the drive motor 10.

Der konkrete Schwenkwinkel des Pumpenmotors 30 wird von der Steuerung 60 in Abhängigkeit der tatsächlichen Auslenkung des Gebers 70 festgelegt, denn dieser ist letztendlich entscheidend für die erzielbare Senkgeschwindigkeit des Auslegerarms. Die weiteren Verbraucher 100, 110 können im Rekuperationsbetrieb weiterhin von der Arbeitspumpe 20 mit Hydrauliköl versorgt werden.The specific pivoting angle of the pump motor 30 is determined by the controller 60 as a function of the actual deflection of the transmitter 70, because this is ultimately decisive for the lowering speed that can be achieved for the extension arm. The other consumers 100, 110 can continue to be supplied with hydraulic oil by the working pump 20 in recuperation mode.

Figur 2 zeigt Einzelheiten des Steuerblocks 90 für die Ansteuerung des Aktors 80 sowie weiterer Verbraucher 100 gemäß einem ersten Ausführungsbeispiel. Die sonstigen Komponenten entsprechen dem Aufbau der Figur 1. Die gemeinsame Druckleitung der Verdrängereinheiten 20, 30 steht mit einem ersten Steuerschieber 91 in Form eines proportionalen Wegeventils in Verbindung. Dieser umfasst insgesamt drei Schaltstellungen a, b sowie d. Mit a ist die Neutralstellung gekennzeichnet, in der das Ventil vollständig sperrt. In der Schaltstellung b ist die Druckleitung der Verdrängereinheiten 20, 30 mit der Bodenseite des Aktors 80 verbunden, die ausfahrende Kolbenstange führt vorzugsweise zum Anheben des Auslegers. In der Schaltstellung d wird die Druckleitung hingegen mit der Stangeseite des Aktors 80 verbunden, der durch die Verdrängereinheiten 20, 30 bereitgestellte Volumenstrom drückt den Kolben aktiv in die Zylindereinheit und der Ausleger wird "aktiv" gesenkt. Figure 2 shows details of the control block 90 for controlling the actuator 80 and further consumers 100 according to a first embodiment. The other components correspond to the structure of the Figure 1 . The common pressure line of the displacement units 20, 30 is connected to a first control slide 91 in the form of a proportional directional control valve. This comprises a total of three switch positions a, b and d. The neutral position in which the valve blocks completely is marked with a. In the switch position b, the pressure line of the displacement units 20, 30 is connected to the bottom side of the actuator 80, the extending piston rod preferably leads to the lifting of the boom. In the switching position d, however, the pressure line is connected to the rod side of the actuator 80, the volume flow provided by the displacement units 20, 30 actively pushes the piston into the cylinder unit and the boom is "actively" lowered.

Für den Rekuperationsbetrieb wird das Ventil 40 in seine Sperrstellung verbracht, so dass kein Öl von der Verdrängereinheit 30 zum Steuerschieber 91 fließen kann. Der Steuerschieber 91 bleibt in Neutralstellung a und das Ventil 50 wird geöffnet. Die Verdrängereinheit 30 wird in Abhängigkeit von der Auslenkung des Gebers 70, der die Senkgeschwindigkeit vorgibt, auf einen bestimmten negativen Schwenkwinkel gestellt. Dadurch senkt sich die Ausrüstung mit der gewünschten Geschwindigkeit ab. Bei dem Absenkvorgang wird auf der Stangenseite des Zylinders 80 Öl benötigt, das über das Nachsaugventil 93 des Steuerblocks 90 aus dem Tank bereitgestellt wird. Die Verdrängereinheit 30 erzeugt ein Moment, das durch den Druck, der im Zylinderboden des Aktors 80 herrscht, und den eingestellten Schwenkwinkel der Verdrängereinheit 30 bestimmt wird. Durch dieses Moment wird das Antriebsaggregat 10 entlastet.For the recuperation operation, the valve 40 is brought into its blocking position so that no oil can flow from the displacer unit 30 to the control slide 91. The control slide 91 remains in neutral position a and the valve 50 is opened. The displacer unit 30 is set to a specific negative pivot angle as a function of the deflection of the transmitter 70, which specifies the lowering speed. This will lower the equipment at the desired speed. During the lowering process, oil is required on the rod side of the cylinder 80, which oil is made available from the tank via the suction valve 93 of the control block 90. The displacement unit 30 generates a moment that is determined by the pressure that prevails in the cylinder base of the actuator 80 and the set pivot angle of the displacement unit 30. This moment relieves the drive unit 10.

Sobald auf der Stangenseite Druck benötigt wird, um die Senkbewegung aufrecht zu erhalten, muss in den Modus "aktives senken" umgeschaltet werden. Hierzu wird das Ventil 40 in seine Durchflussstellung geschaltet, während das Ventil 50 in Sperrstellung geht. Öl kann nun von der Verdrängereinheit 30 zum Steuerschieber 91 fließen, der in der Stellung 91d steht. Der Steuerschieber 91 muss das Öl von den Pumpen 20, 30 zur Stangenseite des Hubzylinders 80 weiterleiten. Das Öl aus der Bodenseite muss über den Steuerschieber 91 zum Tank zurückfließen, das Ventil 50 bleibt gesperrt. Die Verdrängereinheit 30 agiert in diesem Betriebszustand als zweite Arbeitspumpe oder als Pumpe für weitere Verbraucher 100.As soon as pressure is required on the rod side in order to maintain the lowering movement, the "active lowering" mode must be switched to. For this purpose, the valve 40 is switched to its flow position, while the valve 50 goes into the blocking position. Oil can now flow from the displacement unit 30 to the control slide 91, which is in position 91d. The control slide 91 has to convey the oil from the pumps 20, 30 to the rod side of the lifting cylinder 80. The oil from the bottom must flow back to the tank via the control slide 91, which Valve 50 remains blocked. In this operating state, the displacement unit 30 acts as a second working pump or as a pump for additional consumers 100.

Für den regulären Arbeitsbetrieb, d.h. zum Anheben des Auslegers wird das Ventil 40 geöffnet, Öl kann von der Verdrängereinheit 30 zum Steuerschieber 91 fließen. Das Ventil 50 bleibt geschlossen. Die Verdrängereinheit 30 ist in diesem Betriebszustand eine zweite Arbeitspumpe oder eine Pumpe für weitere Verbraucher 100.For regular work, i.e. the valve 40 is opened to raise the boom, and oil can flow from the displacement unit 30 to the control slide 91. The valve 50 remains closed. In this operating state, the displacement unit 30 is a second working pump or a pump for additional consumers 100.

Die Ansteuerung des weiteren Verbrauchers in Form einer zweiten Kolbenzylindereinheit 100 ist ähnlich mittels eines zweiten baugleichen Steuerschiebers 92 sowie zusätzlichen Nachsaugeventilen verwirklicht.The activation of the additional consumer in the form of a second piston-cylinder unit 100 is implemented similarly by means of a second structurally identical control slide 92 and additional suction valves.

Eine modifizierte Ausführungsform der Hydraulik ist Figur 3 zu entnehmen. Gleiche Bauteile sind mit identischen Bezugszeichen versehen. Gegenüber der Ausführungsvariante der Figur 2 wird stromabwärts nach dem zweiten Wegeventil 50, d.h. zwischen dem Ventil 50 und der zweiten Verdrängereinheit 30, zusätzlich eine variable Messblende 120 eingefügt. Dieses proportional steuerbare Wegeventil 120 nimmt einen Öffnungsgrad zwischen einer Endstellung mit vollem bidirektionalen Durchfluss und einer zweiten Endstellung, in der das Ventil 120 vollständig sperrt, ein. Dadurch lässt sich der Volumenstrom zwischen dem Wegeventil 50 und der Verdrängereinheit 30 auf einen bestimmten Volumenstrom drosseln. Der aktuelle Öffnungsgrad der Drossel 120 wird ebenfalls durch die Steuerung 60 eingestellt. Über die Drossel 120 soll beispielsweise verhindert werden, dass der Motor 10 durch das abgegebene Moment der Verdrängereinheit 30 beschleunigt wird. Hierfür ist eine Reduzierung des Volumenstroms notwendig, was durch die entsprechende Reduzierung des Querschnitts im Ventil 120 erreicht wird.A modified embodiment of the hydraulics is Figure 3 refer to. Identical components are provided with identical reference symbols. Compared to the variant of the Figure 2 a variable measuring orifice 120 is additionally inserted downstream after the second directional control valve 50, ie between the valve 50 and the second displacement unit 30. This proportionally controllable directional valve 120 takes an opening degree between an end position with full bidirectional flow and a second end position in which the valve 120 blocks completely. As a result, the volume flow between the directional valve 50 and the displacement unit 30 can be throttled to a specific volume flow. The current degree of opening of the throttle 120 is also set by the controller 60. The throttle 120 is intended, for example, to prevent the motor 10 from being accelerated by the torque output by the displacement unit 30. A reduction in the volume flow is necessary for this, which is achieved by reducing the cross section in the valve 120 accordingly.

Als weitere Änderung gegenüber der Figur 2 umfasst der Steuerschieber 91 des Steuerblocks 90 der Figur 3 eine zusätzliche Schaltstellung 91c. Ist der Volumenstrom aufgrund der geforderten Sollgeschwindigkeit des Aktors 80 größer als der mögliche Volumenstrom über die Verdrängereinheit 30, wird der Steuerschieber 91 in die Stellung 91c geschaltet.Another change compared to the Figure 2 comprises the control slide 91 of the control block 90 of Figure 3 an additional switch position 91c. If the volume flow due to the required setpoint speed of the actuator 80 is greater than the possible volume flow through the displacement unit 30, the control slide 91 is switched to the position 91c.

Alternativ zur Modifikation des Steuerschiebers 91 mit der zusätzlichen Schaltstellung 91c kann ein zusätzliches Bypassventil 130 stromabwärts am Wegeventil 50 angeordnet werden, wie dies in Figur 4 gezeigt ist. Dieses proportional steuerbare Wegeventil 130 schaltet, je nach Öffnungsgrad, einen Bypass des im Rekuperationsbetrieb erzeugten Volumenstroms in den Hydrauliktank. Ist der Volumenstrom aufgrund der geforderten Sollgeschwindigkeit des Aktors 80 größer als der maximal mögliche Volumenstrom der Verdrängereinheit 30, wird das Bypassventil 130 soweit geöffnet, dass die geforderte Senkgeschwindigkeit erzielt werden kann.As an alternative to modifying the control slide 91 with the additional switch position 91c, an additional bypass valve 130 can be arranged downstream on the directional control valve 50, as shown in FIG Figure 4 is shown. This proportionally controllable directional valve 130 switches, depending on the degree of opening, a bypass of the volume flow generated in recuperation operation into the hydraulic tank. If the volume flow is greater than the maximum possible volume flow of the displacement unit 30 due to the required setpoint speed of the actuator 80, the bypass valve 130 is opened to the extent that the required lowering speed can be achieved.

Die vorgestellten Ausführungsbeispiele der Hydraulikkreise der Figuren 1 bis 4 lassen sich nicht nur für die Energierückgewinnung bei Linearantrieben einsetzen, sondern das vorgestellte Funktionsprinzip kann ebenfalls bei Rotationsantrieben zur Anwendung kommen. Gezeigt wird dies am Beispiel der Figur 5. Der Hydraulikaufbau entspricht im Wesentlichem dem Hydraulikschaltbild der Figur 4, gleiche Bestandteile und Komponenten wurden auch in Figur 5 mit denselben Bezugszeichen wir in den Figuren 1 bis 4 bezeichnet. Zur diesbezüglichen Beschreibung wird daher auf die vorangegangene Figurenbeschreibung verwiesen.The presented exemplary embodiments of the hydraulic circuits of Figures 1 to 4 can not only be used for energy recovery in linear drives, but the functional principle presented can also be used in rotary drives. This is shown using the example of Figure 5 . The hydraulic structure essentially corresponds to the hydraulic circuit diagram of Figure 4 , same parts and components were also used in Figure 5 with the same reference numerals we in the Figures 1 to 4 designated. For the relevant description, reference is therefore made to the preceding description of the figures.

Im Unterschied zur Figur 4 wird in Figur 5 mittels des Steuerblockes ergänzend zu den Linearaktoren ein Rotationsantrieb 110 angesteuert. Der Rotationsantrieb kann bspw. ein Fahrantrieb der Arbeitsmaschine sein. Dazu ist dieser unter anderem um die zusätzlichen proportionalen Steuerventile 95, 96 ergänzt worden, die für die notwendige Hydraulikversorgung des Antriebes 110 sorgen. Auch hier soll beim Abbremsen des rotatorischen Verbrauchers 110 Energie zurückgewonnen werden, um mittels der Verdrängereinheit 30 ein Moment an den Verbrennungsmotor 10 abzugeben.In contrast to the Figure 4 is in Figure 5 A rotary drive 110 is controlled by means of the control block in addition to the linear actuators. The rotary drive can, for example, be a travel drive for the work machine. For this purpose, this has been supplemented, among other things, by the additional proportional control valves 95, 96, which provide the necessary hydraulic supply to the drive 110. Here too, when the rotary consumer 110 is braked, energy is to be recovered in order to deliver a torque to the internal combustion engine 10 by means of the displacement unit 30.

Im regulären Arbeitsbetrieb des Verbrauchers 110 wird das Ventil 40 in die offene Stellung geschaltet, wodurch Öl von der Verdrängereinheit 30 zum Steuerschieber 90 fließen kann. Das Ventil 50 muss geschlossen sein. Die Ventile 95, 96 des Steuerblockes 90 geben in Abhängigkeit der Stellung des nun vorgesehenen Gebers 114 einen Öffnungsquerschnitt frei, wodurch die geforderte Geschwindigkeit und/oder Drehzahl des Motors 110 eingestellt werden kann. Zudem kann durch die Schaltposition der Ventile 95, 96 die Drehrichtung vorgegeben werden. Der Rotationsantrieb 110 kann beschleunigt bzw. die aktuelle Rotationsgeschwindigkeit gehalten werden.In the regular working operation of the consumer 110, the valve 40 is switched to the open position, whereby oil can flow from the displacement unit 30 to the control slide 90. The valve 50 must be closed. The valves 95, 96 of the control block 90 give depending on the position of the transmitter now provided 114 free an opening cross section, whereby the required speed and / or rotational speed of the motor 110 can be set. In addition, the direction of rotation can be specified by the switching position of the valves 95, 96. The rotary drive 110 can be accelerated or the current speed of rotation can be maintained.

Im Brems- bzw. Rekuperationsbetrieb des Antriebes 110 wird das Ventil 40 in die geschlossene Stellung geschaltet, daher kann kein Öl von der Verdrängereinheit 30 zum Steuerblock 90 fließen. Das Ventil 50 wird geöffnet. Dreht der Motor 110 im Uhrzeigersinn, so muss das Ventil 95 in der unteren Regelposition sein. Das Ventil 96 ist in der geschlossenen Position. Das zusätzliche Wege-Ventil 112 befindet sich in diesem Fall auf der Ablaufseite des Motors 110 und muss in der offenen Schaltstellung sein, wodurch das ablaufende Öl über die Verdrängereinheit 30 in den Tank geleitet werden kann. Die Verdrängereinheit 30 wird auf einen bestimmten negativen Schwenkwinkel gestellt, der von der ECU 60 vorgegeben wird. Die ECU 60 errechnet den Wert des Schwenkwinkels aus der Antriebs-Drehzahl, die der Sensor 111 vorgibt, und der erfassten Stellung des Gebers 114.In the braking or recuperation operation of the drive 110, the valve 40 is switched to the closed position, so no oil can flow from the displacement unit 30 to the control block 90. The valve 50 is opened. If the motor 110 rotates clockwise, the valve 95 must be in the lower regulating position. The valve 96 is in the closed position. In this case, the additional directional valve 112 is located on the outlet side of the motor 110 and must be in the open switch position, as a result of which the draining oil can be conducted via the displacement unit 30 into the tank. The displacer unit 30 is set to a specific negative swivel angle which is specified by the ECU 60. The ECU 60 calculates the value of the swivel angle from the drive speed specified by the sensor 111 and the detected position of the transmitter 114.

Die Verdrängereinheit 30 erzeugt ein Moment, das sich aus dem erzeugten Hydraulikdruck des Antriebs 110 während des Bremsvorgangs und dem eingestellten Schwenkwinkel der Verdrängereinheit 30 ergibt, und gibt dieses an den Verbrennungsmotor 10 ab. Die weiteren Verbraucher 80, 100 können währenddessen von der Arbeitspumpe 20 mit Öl versorgt werden.The displacement unit 30 generates a torque that results from the hydraulic pressure generated by the drive 110 during the braking process and the set pivot angle of the displacement unit 30, and outputs this to the internal combustion engine 10. Meanwhile, the other consumers 80, 100 can be supplied with oil by the working pump 20.

Wird nur der Antrieb 110 angesteuert (z.B. Fahrantrieb bei einem Mobilbagger auf öffentlichen Straßen), dann kann eine Regelung ähnlich einem geschlossenen Kreis erfolgen. Die Arbeitspumpe 20 und eines der Ventile 95 oder 96 (je nach Fahrtrichtung) geben die Geschwindigkeit des Motors 110 in Abhängigkeit von dem Geber 114 vor. Je nach Fahrtrichtung muss immer eines der Ventile 112, 113, das auf der Ablaufseite des Motors 110 ist, in offener Stellung sein. So fließt das ablaufende Öl über das Ventil 120 und über die Verdrängereinheit 30 zurück.If only the drive 110 is activated (eg travel drive in a mobile excavator on public roads), a closed-loop control can take place. The working pump 20 and one of the valves 95 or 96 (depending on the direction of travel) specify the speed of the motor 110 as a function of the encoder 114. Depending on the direction of travel, one of the valves 112, 113, which is on the outlet side of the motor 110, must always be in the open position. The draining oil thus flows back via the valve 120 and via the displacement unit 30.

Die Funktionalität der Ventile 120 und 130 entspricht der Funktion, die bereits anhand des Ausführungsbeispiels der Figur 4 erläutert wurde. Sollte der rotatorische Verbraucher 110 über ein Bremsventil verfügen (hier nicht dargestellt), dann muss dieses natürlich auch durch die ECU 60 steuerbar sein. Die Einbindung des Rotationsantriebs könnte selbstverständlich auch, bei entsprechender Erweiterung des Steuerblockes 90, auch in eines der Ausführungsbeispiele gemäß den Figuren 1 bis 3 erfolgen.The functionality of the valves 120 and 130 corresponds to the function that has already been described using the exemplary embodiment of FIG Figure 4 was explained. If the rotary consumer 110 has a brake valve (not shown here), then this must of course also be controllable by the ECU 60. The integration of the rotary drive could of course also, with a corresponding expansion of the control block 90, also in one of the exemplary embodiments according to FIGS Figures 1 to 3 respectively.

Das hier beschriebene System zur Rekuperation (insbesondere die Ausführungsbeispiele gemäß den Figuren 1 bis 5) kann nicht nur für das hier dargestellte LS-System umsetzbar sein, sondern auch für Systeme mit elektrischer Pumpenregelung.The recuperation system described here (in particular the exemplary embodiments according to FIGS Figures 1 to 5 ) can be implemented not only for the LS system shown here, but also for systems with electrical pump control.

In Fig. 5 ist ein Mischsystem aus LS-Ventilen und getrennten Steuerkanten-Ventilen dargestellt. Wird das Hydrauliksystem als reines System mit getrennten Steuerkanten-Ventilen ausgeführt (ohne Druckwaagen), dann ist eine elektrische Pumpenregelung zwingend erforderlich. Durch ein solches System wird die Rekuperation - wie hier beschrieben - wesentlich vereinfacht, da im Fall der Rekuperation das Ventil im Ablaif geschlossen werden kann und das Ventil im Zulauf nur bei Bedarf geöffnet werden kann.In Fig. 5 a mixed system of LS valves and separate control edge valves is shown. If the hydraulic system is designed as a pure system with separate control edge valves (without pressure compensators), an electric pump control is absolutely necessary. Such a system makes recuperation - as described here - considerably easier, since in the case of recuperation the valve in the outlet can be closed and the valve in the inlet can only be opened when required.

Alternativ zu Fig. 1, in der 30 ein Pumpenmotor ist, könnte die Verdrängereinheit 30 in der Form einer elektrisch geregelten Pumpe mit Rückschlagventil in der Ansaugung ausgeführt sein. Dadurch könnte das Ventil 40 entfallen, was insbesondere in Figur 6 dargestellt ist. Auch ist hier dann das Ventil 50 direkt mit der eigentlichen Saugseite der Pumpe 30 verbunden, die im Rekuperationsbetrieb als Druckeingang agiert.alternative to Fig. 1 , in which 30 is a pump motor, the displacement unit 30 could be designed in the form of an electrically controlled pump with a check valve in the suction. As a result, the valve 40 could be omitted, which is particularly evident in FIG Figure 6 is shown. Here, too, the valve 50 is then directly connected to the actual suction side of the pump 30, which acts as a pressure input in recuperation mode.

Werden große Energiemengen zurück ins System gespeist, dann ist es sinnvoll eine Energiespeichereinrichtung einzubauen, wie sie zum Beispiel in der EP 2 722 530 A1 beschrieben ist, auf deren Inhalt an dieser Stelle vollumfänglich Bezug genommen wird.If large amounts of energy are fed back into the system, then it makes sense to install an energy storage device, such as that in the EP 2 722 530 A1 is described, the content of which is fully referred to at this point.

Claims (10)

  1. Work machine having at least one hydraulic actuator (80) for actuating a piece of working equipment, further hydraulic consumers (100, 110), two displacement consumers (20, 30) driven by drive assembly (10) of the work machine, and a control block (90), wherein the first displacement unit (20) feeds the control block (90) with hydraulic medium from a hydraulic tank, the second displacement unit (30) in the working mode feeds the control block (90) with hydraulic medium from a hydraulic tank, and is drivable during a recovery mode by the hydraulic volume displaced by the at least one hydraulic actuator (80) or by a hydraulic consumer (100, 110) in order to feed kinetic energy back to the drive assembly (10) and the control block (90) connects the pressure lines of the first and second displacement unit (30) with the hydraulic actuator (80) and the further consumers (100, 110), wherein at least one first ski selector valve (40) having at least two switch positions is provided whose first switch position releases the flow from the second displacement unit (30) to the control block (90) and whose second switch position interrupts a volume flow between the second displacement unit (30) and the control block (90), and wherein at least one second ski selector valve (50) having at least two switch positions is provided via which a direct connection between the at least one hydraulic actuator (80) and the second displacement unit (30), in particular a volume flow from the actuator (80) to the second displacement unit (30), can be released or blocked.
  2. Work machine in accordance with claim 1, characterized in that a machine control (60) is provided to control the first (40) and second (50) ski selector valves that switches the first ski selector valve (40) into its blocked position and the second ski selector valve (50) into its flow position in the recovery mode and that brings the first ski selector valve (40) into its flow position and the second ski selector valve (50) into its blocked position in the working mode.
  3. Work machine in accordance with one of the preceding claims, characterized in that the second displacement unit (30) is an adjustable pump motor or an electrically regulated pump having a check valve in the suction.
  4. Work machine in accordance with claims 2 and 3, characterized in that the machine control (60) of the work machine sets the pivot angle of the adjustable pump motor (30) or of the electrically regulated pump in the recovery mode in dependence on a desired movement speed of the hydraulic actuator (80), in particular in dependence on the actual position of an operating lever (70) for the actuator actuation and/or in dependence on the detected movement speed, in particular the rotary speed, of the actuator (80).
  5. Work machine in accordance with one of the preceding claims, characterized in that the at least one hydraulic actuator (80) is a piston-in-cylinder unit that preferably serves the actuation of a boom of the work machine, with a recovery mode preferably taking place during a lowering movement of the boom.
  6. Work machine in accordance with one of the preceding claims, characterized in that the at least one actuator (80) is a rotary drive, preferably a travel drive of the work machine, with a recovery mode preferably taking place during the braking of the rotational movement.
  7. Work machine in accordance with one of the preceding claims, characterized in that the further hydraulic consumers (100, 110) can be supplied with hydraulic energy by the first displacement unit (20) in the recovery mode.
  8. Work machine in accordance with claim 2, characterized in that at least one restrictor (120), in particular a variable aperture restrictor, preferably in the form of a proportional ski selector valve having an open and a blocking end position, is arranged between the second ski selector valve (50) and the second displacement unit (30), with the degree of opening of the restrictor (120) being selected by the machine control such (60) that kinetic energy fed back by the second displacement unit (30) does not result in a speed increase of the drive assembly.
  9. Work machine in accordance with claim 2, characterized in that at least one proportionally controllable bypass valve (130) is provided at the output of the second ski selector valve (50) and its degree of opening can be increased by the machine control (60) if the volume flow to be displaced due to a movement speed of the actuator (80) desired in the recovery mode is greater than the maximum possible volume flow for driving the second displacement unit (30).
  10. Work machine in accordance with claims 1-5, 7-9, characterized in that the work machine is a hydraulic excavator and the at least one hydraulic actuator (80) is a piston-in-cylinder unit for actuating the excavator arm.
EP18212578.1A 2018-01-29 2018-12-14 Working machine with hydraulics for energy recuperation Active EP3517790B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102018101924.6A DE102018101924A1 (en) 2018-01-29 2018-01-29 Work machine with hydraulics for energy recuperation

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EP3517790A1 EP3517790A1 (en) 2019-07-31
EP3517790B1 true EP3517790B1 (en) 2020-10-21

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US (1) US10927867B2 (en)
EP (1) EP3517790B1 (en)
CN (1) CN110094377B (en)
DE (1) DE102018101924A1 (en)
ES (1) ES2845206T3 (en)

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DE102022206501A1 (en) * 2022-06-28 2023-12-28 Robert Bosch Gesellschaft mit beschränkter Haftung Hydraulic drive and method for regenerative lowering of an element of a work machine

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DE102006060351B8 (en) * 2006-12-20 2008-07-24 Sauer-Danfoss Gmbh & Co Ohg Hydraulic circuit with energy recovery
WO2011041410A2 (en) * 2009-09-29 2011-04-07 Purdue Research Foundation Regenerative hydraulic systems and methods of use
CN103597220B (en) 2011-06-15 2016-02-17 日立建机株式会社 The power regeneration device of Work machine
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EP3517790A1 (en) 2019-07-31
CN110094377B (en) 2022-10-28
RU2019102201A (en) 2020-07-28
US10927867B2 (en) 2021-02-23
US20190234049A1 (en) 2019-08-01
DE102018101924A1 (en) 2019-08-01
CN110094377A (en) 2019-08-06
RU2019102201A3 (en) 2022-03-25
ES2845206T3 (en) 2021-07-26

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