Hydraulic system for supplying a pressure medium to construction machinery, and construction machinery

Abstract

The present invention provides a hydraulic system for supplying a pressure medium to construction machinery, and construction machinery. [Solution] A hydraulic system (30) including a machine-side hydraulic unit (40) having a motor-driven machine-side pump (33) that pressurizes and delivers a pressure medium from a machine-side tank (37), and an additional hydraulic unit (41) having an electric aggregator-side pump (34) that pressurizes and delivers a pressure medium. The non-pressurized inlet connection (47) of the additional hydraulic unit (41) is connectable to the machine-side hydraulic system (40), and the machine-side hydraulic unit (40) has a switching device (35), which is connected to a pressurized line (44) from the machine-side pump (33) and is also connectable to a pressure-resistant outlet connection (46) of the additional hydraulic unit (41), and is further configured to supply pressurized pressure medium from the machine-side pump (33) and / or the aggregator-side pump (34) to the machine-side hydraulic system (36).

Description

TECHNICAL FIELD

[0001] The present invention relates to a hydraulic apparatus for supplying pressure medium to construction machinery, particularly civil engineering machinery, and to a construction machinery, particularly civil engineering machinery, equipped with such an apparatus.

BACKGROUND ART

[0002] Some construction machinery, particularly in the field of special deep foundation construction methods, have high power demand (for example, a magnitude of 400 kW or more) and associated high energy requirements. These construction machines may be used in continuous 24 / 7 operation, for example, in the construction of underground continuous walls, soil mixing processes, or piling and vibration processes.

[0003] Large on-board diesel engines are often used as energy sources to supply the energy required for the operation (travel operation, work operation) of these construction machines, but from the perspective of noise and exhaust gas of these drive units, especially at construction sites in urban areas, there is an increasing number of cases where use is not permitted, or only use with time restrictions is permitted.

[0004] To meet the requirements for noise and exhaust gas reduction, electric construction machinery is known, these machines at most only have an integrated battery for very limited working hours, and are always used in a wired manner, particularly in the case of the aforementioned energy-intensive working methods. In these machines, energy supply is performed via an external network connection. Typically, the voltage of the external power supply is 400V AC or 690V AC, and the connected power is several hundred kVA. In this case, the local power grid is utilized as the primary energy source, or an external stationary generator that is operated by an internal combustion engine and can also use alternative fuels, or other electrical energy sources or converters, for example battery-based energy storage systems or fuel cell systems, may be used.

[0005] However, the use of these large, high-output electric construction machines is associated with several fundamental problems.

[0006] Firstly, during the transportation phase of construction machinery to the construction site, electrical infrastructure (like that at the site) is unavailable, so wired machinery cannot be operated without a transport vehicle.

[0007] While alternative solutions are available to address this issue during the transport phase, they require additional costs and extra effort in handling and logistics. For example, a small, low-power generator specifically for transport, or a limited direct hydraulic supply for drive, could be provided, but these are insufficient to power the construction machine's internal hydraulic system during operation.

[0008] During the scaffolding and on-site relocation phases at a construction site, the primary energy source for powering construction machinery is usually already present, but may be unavailable due to cable routing and logistical arrangements at the construction site.

[0009] If a fully powered electrical infrastructure is not yet established on-site by the planned start date of work, for example, because a sufficiently high-performance grid connection has not yet been installed, construction machinery requiring scaffolding cannot be used, causing delays in the start of work.

[0010] Finally, the availability of full-power electrical infrastructure on site can also be compromised by disruptions such as power outages, overloads, so-called "load limits," cable damage, or power supply interruptions caused by construction work, which will force electric construction machinery to shut down.

[0011] Furthermore, because fully electrified construction sites are not yet the standard, the conversion of construction machinery fleets with internal combustion engines to those with electric drive systems is not yet widespread or is being implemented with hesitation. This is because, without sufficient electrical infrastructure at the construction site, operators may not be able to use these machines in subsequent projects, and the economic viability of purchasing electrically wired machinery is not guaranteed. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] European Patent Application Publication No. 4428087 [Patent Document 2] European Patent No. 3550083 [Patent Document 3] European Patent No. 2738397 [Overview of the project] [Problems that the invention aims to solve]

[0013] Therefore, the object of the present invention is to solve at least some of these problems and to satisfy the conflicting requirements of reducing noise and exhaust gases from construction machinery, particularly civil engineering machinery, on the one hand, and improving operational readiness on the other. [Means for solving the problem]

[0014] To achieve this, the present invention proposes a hydraulic system for supplying the pressure medium described in claim 1 to construction machinery, particularly civil engineering machinery, and construction machinery, particularly civil engineering machinery having the features described in claim 14. Preferred configurations are described in the respective dependent claims.

[0015] In particular, the present invention relates to a hydraulic system for supplying a pressure medium (working fluid) to construction machinery, in particular civil engineering machinery, and includes a machine-side hydraulic unit having a motor-driven machine-side pump for pressurizing and discharging the pressure medium from a machine-side tank, a machine-side hydraulic system to which the pressure medium can be supplied, and a return line for returning the pressure medium to the machine-side tank; and an additional hydraulic unit having an electric aggregator-side pump for pressurizing and discharging the pressure medium from an aggregator-side tank, a pressure-resistant outlet connection for the pressurized pressure medium, and a non-pressurized inlet connection for returning the pressure medium to the aggregator-side tank. The hydraulic system according to the present invention is characterized in that the non-pressurized inlet connection of the additional hydraulic unit can be (detachably) connected to the machine-side hydraulic system, and the machine-side hydraulic unit has a switching device, the switching device can be connected to a pressurized line from the machine-side pump and can also be (detachably) connected to a pressure-resistant outlet connection of the hydraulic unit, and is configured to further supply pressurized pressure medium from the machine-side pump and / or aggregator-side pump to the machine-side hydraulic system.

[0016] The construction machine, in particular civil engineering machine, according to the present invention includes a lower carriage and an upper carriage mounted on the lower carriage, and a hydraulic system according to the present invention, wherein the machine-side hydraulic unit of the hydraulic system is a component of the internal hydraulic supply system of the construction machine, and its machine-side pump may be driven by a machine-side motor, in particular an internal combustion engine, such as a gasoline engine, diesel engine, gas engine, or gas turbine, and an additional hydraulic unit of the hydraulic system is designed to supply a pressure medium for the (full) operation of the construction machine to the internal hydraulic supply system of the construction machine, even when the machine-side motor is off, and the control device of the construction machine is configured to control the function of the additional hydraulic unit, in particular the operation of the aggregator-side pump, for example via a data connection.

[0017] The present invention is based on the fundamental idea of ​​not completely electrifying construction machinery, particularly civil engineering machinery, but rather of not eliminating the (construction) machine-side internal combustion engine as a standard drive device on the machine side. Instead, the present invention allows the use of a conventional device that is itself a known standard device, which includes a machine-side hydraulic unit. The machine-side hydraulic unit is driven by a machine-side internal combustion engine, such as a diesel engine, and is capable of fully meeting the power requirements of the device and supplying power to a connected hydraulic supply system. The hydraulic supply system has a mobile control block and hydraulic consumers such as a winch motor, travel motor, work equipment, and hydraulic cylinders, which perform movement and work operations. Such construction machinery can actually be operated flexibly and without limitation in the aforementioned problem scenarios (transportation, scaffolding, delays or interruptions in electrical infrastructure at construction sites, and use at construction sites without electrical infrastructure).

[0018] However, in order to enable construction machinery to operate on-site with absolutely zero emissions, an additional external electro-hydraulic unit has been proposed in the form of an additional hydraulic unit equipped with an electric aggregator-side pump. For this purpose, a power supply for the additional hydraulic unit is provided, specifically for the electric motor of the aggregator-side pump.

[0019] This power supply may have a connection to an external electrical energy source (construction site power supply, main power supply, or generator), the voltage level of which is typically 400V AC or 690V AC. For example, the local power grid can be used as the primary energy source. However, a generator (with zero CO2 emissions) powered by an internal combustion engine (e.g., using hydrogen as the energy carrier), or a stationary electrical energy source, such as a battery-based rechargeable electrical energy storage system (rechargeable battery) or a converter (generator or fuel cell) that converts and supplies electrical energy, can also be used as a power supply. Such rechargeable electrical storage devices and / or converters may preferably be integrated into or mounted in an additional hydraulic unit.

[0020] This additional electro-hydraulic unit takes the form of an additional external hydraulic unit, which can completely supply hydraulic energy to the construction machine or its hydraulic supply system, that is, all hydraulic components required for the intended operation.

[0021] For this purpose, the non-pressurized inlet connection of the additional hydraulic unit can be detachably connected to the machine-side hydraulic system, and the machine-side hydraulic unit has a switching device that is (detachably) connected to both the pressure guide line from the machine-side pump and the pressure-resistant outlet connection of the additional hydraulic unit. The switching device is further configured to selectively supply the machine-side hydraulic system with pressurized pressure medium from the machine-side pump (when the internal combustion engine is operating) or from the aggregator-side pump (when operating only electrically). In this operating state, the internal combustion engine of the construction machine is shut down, as a result of which the hydraulic pump of the construction machine no longer needs to supply the machine-side hydraulic system, and thus the hydraulic functions of the construction machine, and the desired avoidance of noise and exhaust gas can be achieved.

[0022] A summation operation is also possible and encompassed by the present invention, in which the machine-side hydraulic system is selectively supplied with pressurized pressure medium from both the machine-side pump (still driven by the internal combustion engine) and the aggregator-side electric pump via the switching device. By at least partially sacrificing the reduction of noise and exhaust gas caused by shutting down the internal combustion engine, a higher total hydraulic power can be provided in this mode under certain operating conditions, which is particularly advantageous when the drive unit of the construction machine as the base machine is not designed to meet the corresponding power demand.

[0023] Accordingly, according to the present invention, two hydraulic units are presented, that is, one is a machine-side hydraulic unit equipped with a hydraulic pump driven by the standard engine (especially the internal combustion engine) of the construction machine, and the other is an additional hydraulic unit equipped with a hydraulic pump driven by an electric motor.

[0024] The supply of pressure medium to the hydraulic system of a construction machine by an additional hydraulic unit is effected via a detachable connection between the pressure-resistant hydraulic line and the non-pressurized hydraulic line, that is, between the pressure-resistant outlet connection for the pressurized pressure medium and the non-pressurized inlet connection for returning the pressure medium to the aggregator-side tank, and the corresponding connection on the machine-side hydraulic unit side, preferably via an interface, in which interface, preferably at least the connections for the pressure medium of the interface, preferably also the connections for exchanging control signals and / or operating data (if present), are arranged on a dedicated multi-connector on the additional hydraulic unit.

[0025] The corresponding connections for the hydraulic lines and, if necessary, the corresponding connections for exchanging control signals and / or operating data may also be combined on the side of the supplied construction machine, for example as a corresponding counter interface on a dedicated multi-connector, whereby the connectors can be detachably connected in one step, and the corresponding connections can be established easily and in an operationally safe manner. For this purpose, coupling elements adapted specifically for the connectors can be provided, in which the hydraulic lines and, if present, the data lines are bundled into a line package. In order to ensure the coupled state in an operationally safe manner, the connectors may be provided with a locking mechanism which, in cooperation with a switching device or a valve device, allows the passage of pressure medium or signals via the coupling elements only when the coupling is confirmed at both ends. In this way, the hydraulic unit and hydraulic system of the construction machine and the additional external hydraulic unit are connected in an operationally safe manner to form a common hydraulic apparatus.

[0026] This (hydraulic) interface can be designed for general purpose use so that it can be used in combinations of various construction machines and various additional hydraulic units (with different outputs).

[0027] Preferably, the additional hydraulic unit, in particular the aggregator-side pump, is configured to be controlled by the control device of the supplied construction machine, whereby the control device of the construction machine takes over the control of the generic hydraulic apparatus and executes machine tasks according to the required power requirements.

[0028] For this purpose, a connection (which can be wired or wireless) is provided to the additional hydraulic unit to exchange control signals and / or operational data between the additional hydraulic unit and the control device of the supplied construction machine.

[0029] In the case of a wired connection, in order to exchange control signals and / or operational data between the additional hydraulic unit and the control device of the supplied construction machine, this may be integrated into a corresponding control line or contact within a potentially general-purpose interface / opposite interface for connecting the hydraulic units.

[0030] Even if an additional hydraulic unit is configured to be controlled by the construction machine's control system to ensure the necessary hydraulic supply to the construction machine, at least with respect to the operation of the hydraulic pump, it may have its own control capabilities, and at least some of its functions (power supply, charge management in the case of an internal rechargeable battery, cooling of the pressure medium and / or part of the power supply (rechargeable battery), and function monitoring) may be performed autonomously, without the need for any higher-level control by the construction machine to which it is supplied. Thus, the control of the construction machine may be limited to the hydraulic functions and does not need to be extended with special control functions for the internal operation and monitoring of the additional hydraulic unit.

[0031] The non-pressurized inlet connection of the additional hydraulic unit can function as a pressure equalization line between the machine-side tank and the aggregator-side tank, by being configured to allow for direct (detachable) fluid connection to the machine-side tank and designed to the appropriate dimensions considering the possible flow rate. The direct connection has the advantage that, while the additional hydraulic unit is in operation, a pump installed in the unit can be supplied with pressurized medium or working fluid from the machine-side or aggregator-side tank on the suction side, eliminating the need for an additional tank level equalization function.

[0032] In a further configuration, the return pressure medium or hydraulic fluid from the machine-side hydraulic system may be led to or via a switching device, where the return line of the machine-side hydraulic system is also connected to the switching device, and the non-pressurized inlet connection of an additional hydraulic unit may be connected to the switching device (removably). In this case, the switching device may be designed to function internally to direct the return flow rate of the pressure medium to the machine-side tank or the aggregator-side tank as desired. In this configuration, a smaller diameter passive pressure equalizing line or a controllable bidirectional pressure equalizer may be provided to be connected (removably) between the machine-side tank and the aggregator-side tank.

[0033] The switching device has a controllable directional switching valve element (such as a ball valve or a switchable valve such as a cartridge block) or a passive check valve arrangement for switching between the hydraulic supply from the machine-side hydraulic system and the hydraulic supply to the connected consuming equipment by the machine-side hydraulic unit or an additional hydraulic unit, or for setting cumulative simultaneous supply, thereby allowing the supply flow rate to be actively or passively selected and set.

[0034] In a particularly preferred configuration, the additional hydraulic unit may be mounted on a self-supporting frame, thereby enabling it to be moved, transported, and handled as a functional unit independently of the supplied construction machinery. In this variation, it is preferable that the external hydraulic unit be housed in a separate enclosure from the supplied construction machinery.

[0035] In a configuration as a separate functional unit, the external hydraulic unit may be further designed to be detachably mounted on a mounting base on the upper carriage of the construction machine being supplied, particularly on the ballast base at the rear of the construction machine. This modification facilitates integration with the construction machine because the area of ​​the ballast base usually has sufficient space not occupied by other functional units of the machine, and the ballast base has the necessary strength or load capacity to support the mass of the unit. Furthermore, the mass of the external hydraulic unit itself can be used as ballast for the construction machine.

[0036] However, external hydraulic units may also be designed to be mounted in a different location on the upper carriage of the construction machine, for example, on the side, or to be installed independently next to the construction machine. In the latter case, the connection lines or specific connection elements between the construction machine or machine-side hydraulic unit and the additional external hydraulic unit must be designed to be correspondingly long and protected from damage during operation.

[0037] The present invention will be described below based on exemplary embodiments with reference to the accompanying drawings. [Brief explanation of the drawing]

[0038] [Figure 1] This is an external view of a construction machine (civil engineering machine) and an additional electro-hydraulic unit that is mounted as a rear attachment to the construction machine. [Figure 2] This is a schematic diagram of a modified hydraulic system showing a machine-side hydraulic unit and an additional electro-hydraulic unit. [Modes for carrying out the invention]

[0039] The civil engineering machine 10 illustrated in Figure 1 in the form of a mobile transport device 11 is an example of a construction machine in which the hydraulic system 30 according to the present invention may be used, and is useful in illustrating the features of the present invention.

[0040] The transport device 11 may preferably include a crawler lower carriage 14 on which an upper carriage 16 can be mounted in particular rotatably. The driver's cab 15 and / or control cabinet of the upper carriage 16 is provided with a control device or control unit 17 which can be used to control the functions of the transport device 11 and the functions of the tools 12 attached to the transport device. In particular, via an articulation mechanism 18, the mast 13 may be attached to the upper carriage 16, preferably in an adjustable manner, so that the mast 13 takes a substantially vertical position when in operation.

[0041] According to the illustrated exemplary embodiment, the mast 13 may preferably be configured as a leader mast with a linear guide 19 on its front. In the example of Figure 1, a drilling drive carriage 21 with a rotary drive unit 22 is mounted vertically movable along the linear guide 19. The tools shown in Figure 1 are merely examples, and other tools may also be mounted depending on the work task.

[0042] A cable 23 can be routed through a mast head (not shown) at the upper end of the mast 13, from which an excavation drive carriage 21 is suspended. The other end of the cable 23 is routed to a cable winch 24, which is attached to the upper carriage.

[0043] The construction machine 10 is equipped with a hydraulic system 30 according to the present invention for supplying a pressure medium to the construction machine 10, and one modified example thereof is shown in Figure 2 as a schematic system diagram.

[0044] The hydraulic system 30 includes a (construction) machine-side hydraulic unit 40, which has a machine-side pump 33 driven by the standard drive engine 31 of the construction machine 10, which, under pressure, transfers a pressure medium (working fluid) from a machine-side tank 37 to a machine-side hydraulic system 36 that can be supplied with the pressure medium via a pressurized line 44, and also has a return line 45 for returning the pressure medium back to the machine-side tank 37. The hydraulic system 30 also includes an additional external hydraulic unit 41.

[0045] The standard drive engine 31 of the construction machine 10 is housed within the casing of the upper carriage 16 and may be, for example, a gasoline engine, diesel engine, gas engine, or internal combustion engine of the gas turbine type.

[0046] The machine-side hydraulic system or hydraulic supply system 36 has, in a manner known in itself, a mobile control block and hydraulic consumers such as a winch motor, travel motor, work equipment, and hydraulic cylinders, and is capable of movement and work operations. According to the present invention, there is no substantial change to this machine-side hydraulic system or hydraulic supply system 36.

[0047] The additional external hydraulic unit 41 includes an aggregator-side pump 34 electrically driven by an electric motor 32 for pressurizing and transferring a pressurized medium from the aggregator-side tank 38, and also includes a pressure-resistant outlet connection 46 connected to the pump 34 for the pressurized medium via a pressure-resistant line 42, and a non-pressurized inlet connection 47 for returning the pressurized medium to the aggregator-side tank 38 via a non-pressurized return line 43.

[0048] The non-pressurized inlet connection 47 of the additional hydraulic unit 41 is detachably connected to the machine-side hydraulic system 40. The machine-side hydraulic unit 40 has a switching device 35, which is hydraulically connected to a pressurized line 44 from the machine-side pump 33 and is also detachably connected to the pressure-resistant outlet connection 46 of the additional hydraulic unit 41 (via an interface 39 described later). The switching device 35 is configured to selectively supply pressurized pressure medium from the machine-side pump 33 and / or the aggregator-side pump 34 to the machine-side hydraulic system 36, thereby optionally supplying pressurized pressure medium or working fluid to the machine-side hydraulic system 36 and its consuming equipment from the machine-side pump 33 driven by the construction machine's drive engine 31, or from the electric pump 34 of the external additional hydraulic unit 41 (preferably allowing the construction machine's drive engine 31 to then be stopped, reducing noise and exhaust emissions).

[0049] It is also possible to cumulatively supply the pressure medium or working fluid to the machine-side hydraulic system 36 via both pumps 33 and 34 in a saturation operation, provided that the switching device 35 is designed at the corresponding switching position. This modification is useful, for example, when the hydraulic output of the machine-side pump or aggregator-side pump alone is insufficient for a particular work task or mounting device.

[0050] To perform the hydraulic switching function, the switching device 35 includes an internal connection channel and an actively (manually or motor-driven) controllable directional switching valve element or a passive check valve device, depending on the switching stage, to switch the forward flow rate of the pressurized pressure medium from each pump 33, 34 to the machine-side hydraulic system 36.

[0051] The non-pressurized inlet connection 47 and pressure-resistant outlet connection 46 for the pressure medium of the additional hydraulic unit 41 may be arranged as separate connections or incorporated into a common interface 39 with a dedicated composite connector on the additional hydraulic unit 41 side, for example on a connection panel on the housing 54 of the enclosed unit 50, or at one end of a bundle of connection lines, and the interface 39 may be detachably coupled / connected to the corresponding opposing interface on the supplying construction machine 10 side to establish the corresponding connection. If configured as a wired connection, connections for exchanging control signals and / or operating data between the additional hydraulic unit 41 and the control device 17 of the construction machine 10 may also be incorporated into the interface 39 and the bundle of connection lines.

[0052] To drive the functions of the additional hydraulic unit 41, particularly the electric aggregator-side pump 34, the additional hydraulic unit 41 has a power supply. This power supply includes, as shown in Figure 1, a connecting cable 52 for an external electrical energy source, particularly a power supply at the construction site, a main power supply, or an external generator, and / or a rechargeable storage device for electrical energy, particularly a rechargeable battery, and / or a converter for converting and supplying electrical energy, particularly a generator or fuel cell. The rechargeable storage device and / or converter may be integrated into or mounted in the housing 54 of the additional hydraulic unit 41, if provided.

[0053] To control the hydraulic operation within a system having hydraulic units connected to one another via interface 39, an additional hydraulic unit 41, particularly an aggregator-side pump 34, is configured to be controlled by a control unit 17 of the construction machine 10, which acts as a higher-level control unit, according to power demand. For this purpose, the hydraulic system 30 includes connections, which can be wired or wireless, for exchanging control signals and / or operational data between the additional hydraulic unit 41 (specifically, a dependent control unit incorporated therein) and the higher-level control unit 17 of the construction machine 10. Although dependent with respect to the control of the aggregator-side pump 34, the additional hydraulic unit 41 or its incorporated dependent control unit may be configured to autonomously and independently perform at least some of its operational functions, such as power supply, charging management of rechargeable batteries, cooling of pressure medium or rechargeable batteries or motors, and function monitoring, particularly without control by the construction machine 10 or its control unit 17.

[0054] To ensure that an unpressurized pressure medium or working fluid is reliably supplied (suction) to the pump 34 of the additional hydraulic unit 41, the unpressurized inlet connection 47 of the additional hydraulic unit 41 can be directly connected to the machine-side tank 37 via the interface 39, as shown in Figure 2, thereby functioning as a pressure equalization connection line between the machine-side tank 37 and the aggregator-side tank 38.

[0055] In the modified example shown in Figure 2, the return line 45 from the machine-side hydraulic system 36 is directly connected to the machine-side tank 37, returning the pressure medium to the machine-side tank 37 after it has passed through. However, in a modified example not shown, the return line 45 of the machine-side hydraulic system 36 may first be connected to a switching device 35, and the unpressurized inlet connection 47 of an additional hydraulic unit 41 may also be connected to the switching device 35 via an interface 39. The switching device 35 may then be configured, by internal connection channels and an actively (manually or motor-driven) controllable directional switching valve element, to further direct the return flow rate of the pressure medium to the machine-side tank 37 (when the machine-side pump 33 is powered by the machine-side engine 31) or the aggregator-side tank 38 (when the aggregator-side pump 34 is powered by an electric motor 32). Furthermore, a passive pressure equalization line or a controllable bidirectional pressure equalization device (not shown) can be connected between the machine-side tank 37 and the aggregator-side tank 38 (via interface 39) to ensure that the filling level of the pressure medium in the tanks is reliably equalized. Moreover, the tanks 37 and 38 do not need to be the same size.

[0056] A particularly advantageous configuration of the present invention is that an additional hydraulic unit 41 is mounted on a self-supporting support frame 53 and can be relocated independently of each supplied construction machine 10 as an independent functional unit 50 via this frame. The functional components of the hydraulic unit 41 are housed and sealed in a housing 54 independent of the construction machine 10 in this connection, as shown in Figure 1. Such a functional unit 50 is preferably designed to be detachably mounted to a well-designed mounting section 51 of the construction machine 10. Due to the size and mass of the functional unit 50, the ballast mount of the construction machine 10 is often located in the rear region of the upper carriage 16, which is suitable as a mounting section 51, as shown in Figure 1.

[0057] As shown in Figure 2 and described herein, each single pump 33, 34 of the machine-side hydraulic unit 40 and the additional hydraulic unit 41 represents the entire respective pump line and may consist of one or more pumps for the working hydraulic system only, and possibly additional peripheral pumps.

[0058] Although not shown in the drawings, filters may be provided on the machine side and / or in additional hydraulic units 41 to purify the pressure medium returned to their respective tanks. Similarly, although not shown, a cooling system may be provided in additional hydraulic units 41 to cool the pressure medium and / or, if present, part of the power supply (rechargeable battery) or other components.

Claims

1. A hydraulic system (30) for supplying a pressure medium to construction machinery, particularly civil engineering machinery, A machine-side hydraulic unit (40) comprising a motor-driven machine-side pump (31) for pressurizing and discharging a pressure medium from a machine-side tank (37), a machine-side hydraulic system (36) to which the pressure medium can be supplied, and a return line (45) for returning the pressure medium to the machine-side tank (37), The additional hydraulic unit (41) comprises an electric aggregator-side pump (34) for pressurizing and discharging a pressure medium from an aggregator-side tank (38), a pressure-resistant outlet connection (46) for the pressurized pressure medium, and a non-pressurized inlet connection (47) for returning the pressure medium to the aggregator-side tank (38), The non-pressurized inlet connection (47) of the additional hydraulic unit (41) is connectable to the machine-side hydraulic system (40), and The machine-side hydraulic unit (40) is characterized by including a switching device (35) which is connected to a pressurized line (44) from the machine-side pump (33), and is also connectable to the pressure-resistant outlet connection (46) of the additional hydraulic unit (41), and is further configured to supply the pressurized pressure medium from the machine-side pump (31) and / or the aggregator-side pump (32) to the machine-side hydraulic system (36), Hydraulic device (30).

2. The additional hydraulic unit (41) is characterized in that it includes a power supply for the electric motor (32) of the electric aggregator-side pump (34), The hydraulic apparatus (30) according to claim 1.

3. The power supply includes an external electrical energy source, particularly a power source at a construction site, a main power source, or a connection to a generator (52), and / or a rechargeable storage device for electrical energy, particularly a rechargeable battery, and / or a converter for converting and supplying electrical energy, particularly a generator or fuel cell, wherein preferably the rechargeable storage device and / or the converter are integrated with or mounted to the additional hydraulic unit (41), if provided. The hydraulic device (30) according to claim 2.

4. The additional hydraulic unit (41), in particular the aggregator-side pump (34), is configured to be controlled by the control device (17) of the supplied construction machine (10), A hydraulic device (30) according to any one of claims 1 to 3.

5. In particular, a connection is provided, either wired or wirelessly, for exchanging control signals and / or operational data between the additional hydraulic unit (41) and the control device (17) of the construction machine (10) to which it is supplied. The hydraulic apparatus (30) according to claim 4.

6. The additional hydraulic unit (41) is configured to autonomously perform at least some of its functions, such as power supply, charge management, cooling, and function monitoring, without control by the supplied construction machine (10) / the construction machine (10), A hydraulic device (30) according to any one of claims 1 to 5.

7. The non-pressurized inlet connection (47) of the additional hydraulic unit (41) is capable of being directly connected to the machine-side tank (37) and functions as a pressure equalization connection line between the machine-side tank (37) and the aggregator-side tank (38), characterized in that A hydraulic device (30) according to any one of claims 1 to 6.

8. The return line (45) of the machine-side hydraulic system (36) is connected to the switching device (35), the non-pressurized inlet connection (47) of the additional hydraulic unit (41) is connectable to the switching device (35), and the switching device (35) is configured to arbitrarily guide the return flow rate of the pressure medium to the machine-side tank (37) or the aggregator-side tank (38), characterized in that A hydraulic device (30) according to any one of claims 1 to 6.

9. A passive pressure equalization line or a controllable bidirectional pressure equalization device is provided connectably between the machine-side tank (37) and the aggregator-side tank (38), characterized in that A hydraulic device (30) according to any one of claims 1 to 8.

10. The switching device (35) is characterized by having a controllable directional switching valve element or a passive check valve arrangement, and switching the forward flow rate of the pressure medium to the machine-side hydraulic system (40), A hydraulic device (30) according to any one of claims 1 to 9.

11. The pressure-resistant outlet connection (46) and the non-pressurized inlet connection (47) for the pressure medium of the additional hydraulic unit (41), and preferably, if present, a connection for exchanging control signals and / or operational data between the additional hydraulic unit (41) and the control device (17) of the supplied construction machine (10), wherein the connection is detachably connectable to a corresponding opposing interface on the supplied construction machine (10) side to establish the corresponding connection, wherein preferably, at least the connection for the pressure medium of the interface (39), and preferably the connection for exchanging control signals and / or operational data, are also located in the additional hydraulic unit (41) on a dedicated composite connector, for example on a connection panel on the housing (54), or at one end of a bundle of connection lines. A hydraulic device (30) according to any one of claims 1 to 10.

12. The additional hydraulic unit (41) is mounted on a self-supporting support frame (53) and can be rearranged as a unit (50) independently of the supplied construction machine (10), wherein the external hydraulic unit (41) is preferably enclosed in a housing (54) independent of the supplied construction machine (10). A hydraulic device (30) according to any one of claims 1 to 11.

13. The external hydraulic unit (41) is configured to be detachably attached to the mounting receiving portion (51) of the construction machine (10) to which it is supplied, particularly to the ballast receiving portion of the construction machine (10), The hydraulic apparatus (30) according to claim 12.

14. A lower carriage (14) and an upper carriage (16) mounted on the lower carriage (14), A hydraulic system (30) according to any one of claims 1 to 13, wherein the machine-side hydraulic unit (40) is part of the internal hydraulic supply system of the construction machine (10), and the machine-side pump (33) can be driven by a machine-side motor (31), in particular by an internal combustion engine, comprising: The additional hydraulic unit (41) is designed to supply pressure medium to the internal hydraulic supply system in order to operate the construction machine (10) even when the machine-side motor (31) is turned off, and The control device (17) of the construction machine (10) is configured to control the functions of the additional hydraulic unit (41), particularly the operation of the aggregator-side pump (34), especially via data connection. In particular, civil engineering machinery, such as construction machinery (10).

15. The unit (50) comprises a mounting support (51) for the detachable attachment of the additional hydraulic unit to the upper carriage, preferably a mounting support (51) which is a ballast support of the construction machine (10), A construction machine (10) as described in claim 14, which is particularly a civil engineering machine.

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