Method for driving a truck-mounted concrete pump, drive system for a truck-mounted concrete pump, and truck-mounted concrete pump

Abstract

The invention relates to a method for driving a truck-mounted concrete pump (100), wherein the truck-mounted concrete pump (100) comprises at least one boom hydraulic pump (122) with limitable drive torque, which boom hydraulic pump is provided for driving a distribution boom (110) and / or a support (107) of the truck-mounted concrete pump (100), and at least one concrete pump hydraulic pump (121a, 121b, 123, 124), which is provided for driving a concrete pump (116, 118, 119) of the truck-mounted concrete pump (100), wherein the truck-mounted concrete pump (100) is designed for a first operating state in which the distribution boom (110) or the support (107) is in operation and the concrete pump (116, 118, 119) is not in operation and wherein the truck-mounted concrete pump (100) is designed for a second operating state in which the distribution boom (110) or the support (107) and the concrete pump (116, 118, 119) are in operation. The method of the invention comprises the following steps: - determining the operating state of the truck-mounted concrete pump (100) and - limiting the drive torque of the boom hydraulic pump (122) in the second operating state. The invention also relates to a corresponding drive system for a truck-mounted concrete pump and to a truck-mounted concrete pump having a drive system of this kind.

Description

[0001] Method for driving a truck-mounted concrete pump and drive system for a truck-mounted concrete pump and truck-mounted concrete pump

[0002] The invention relates to a method for driving a truck-mounted concrete pump and to a drive system for a truck-mounted concrete pump, wherein the truck-mounted concrete pump comprises at least one boom hydraulic pump with a limitable drive torque, which is provided for driving a placing boom and / or a support of the truck-mounted concrete pump and comprises at least one concrete pump hydraulic pump, which is provided for driving a concrete pump of the truck-mounted concrete pump, wherein the truck-mounted concrete pump is configured for a first operating state in which the placing boom or the support is in operation and the concrete pump is not in operation, and wherein the truck-mounted concrete pump is configured for a second operating state in which the placing boom or the support and the concrete pump are in operation. The invention also relates to a truck-mounted concrete pump with such a drive system.

[0003] Truck-mounted concrete pumps today are typically powered by an internal combustion engine, usually a diesel engine. In a truck-mounted concrete pump, the diesel engine drives the truck chassis to transport the pump to the site. On the construction site, the diesel engine is used to drive the working equipment of the concrete pump body, which is typically hydraulically driven by several hydraulic pumps.

[0004] There are now concepts for driving a truck-mounted concrete pump with an electric motor. The power provided by the electric motor to drive the concrete pump structure is generally much lower than that of a diesel engine, for example because the electrical connection load available on a construction site is low compared to the power of a combustion engine. On construction sites where truck-mounted concrete pumps are typically operated, power connections with different connection loads are available, e.g. 63 A or 125 A, corresponding to approximately 44 kW or 87 kW respectively. Furthermore, accumulators can be used on the construction site or on the truck-mounted concrete pump, for example. These batteries are charged by the construction site's power supply during phases of low power demand and provide additional electrical power to drive the truck-mounted concrete pump during phases of increased power demand.For assembling and dismantling the truck-mounted concrete pump or in cases where only a low power requirement is required for concrete delivery on the construction site, the sole use of a battery may be sufficient, so that no connection to a power supply is necessary.

[0005] In an electrically or hybrid-powered truck-mounted concrete pump, an electric motor typically drives one or more hydraulic pumps to hydraulically drive the concrete pump, placing boom, and other work equipment on the truck. These hydraulic pumps are typically pre-set to be driven by an internal combustion engine with an output of > 200 kW, so that the internal combustion engine does not stall when the hydraulic pumps are running at full power. The term "power" of the hydraulic pumps here refers to the drive torque or torque of the hydraulic pumps, which in the case of adjustable hydraulic pumps, for example axial piston pumps with a swashplate, is usually set to a fixed maximum value via a limiting circuit or regulator. Ultimately, the power of the hydraulic pump is a product of the volume flow and the pressure of the hydraulic flow at the hydraulic pump outlet.For the sake of clarity, the term "drive torque" is used below. If the electric motor is driving hydraulic pumps with an electric motor, the electrical power consumption of the electric motor is already at its upper limit and a hydraulic pump suddenly demands more drive torque, for example, during the switching operations of a two-cylinder piston pump, the electric motor's inverter may be overloaded and shut down for safety reasons or trigger an overload protection device in the construction site's power supply.

[0006] It is therefore an object of the invention to provide an improved method for driving a truck-mounted concrete pump or an improved drive system for a truck-mounted concrete pump, in which the available electrical power is used as effectively as possible for driving the working devices of the truck-mounted concrete pump, in particular so that the maximum possible power is available to the working units of the truck-mounted concrete pump for the respective operating state.

[0007] This object is achieved by a method for driving a truck-mounted concrete pump having the features of claim 1 and a drive system for a truck-mounted concrete pump having the features of claim 9 and a truck-mounted concrete pump according to claim 10.

[0008] According to the invention, the method comprises the following steps:

[0009] - Determine the operating status of the truck-mounted concrete pump,

[0010] - Limiting the drive torque of the mast hydraulic pump in the second operating state.

[0011] This means that in the second operating mode, when the at least one boom hydraulic pump drives the placing boom and / or the outrigger and the at least one concrete pump hydraulic pump drives the concrete pump of the truck-mounted concrete pump, the drive torque of the at least one boom hydraulic pump is limited so that more drive torque is available for the at least one concrete pump hydraulic pump in order to drive the concrete pump with the highest possible drive torque. This prioritization takes place, which is necessary to use the available, limited drive energy as effectively as possible to drive the working units of the truck-mounted concrete pump.

[0012] Advantageous embodiments and further developments of the invention emerge from the dependent claims. It should be noted that the features listed individually in the claims can also be combined with one another in any technologically expedient manner, thus revealing further embodiments of the invention.

[0013] A particularly advantageous embodiment of the invention relates to the fact that the truck-mounted concrete pump further comprises at least one electric motor drivable with different available electrical supply powers for driving the at least one boom hydraulic pump and the at least one concrete pump hydraulic pump, wherein the drive torque of the at least one concrete pump hydraulic pump is limitable and wherein the method comprises the further steps: - determining the available electrical supply power of the at least one electric motor,

[0014] - Limiting the adjustable drive torque of the at least one boom hydraulic pump and / or the at least one concrete pump hydraulic pump depending on the available electrical supply power of the at least one electric motor.

[0015] By taking into account the available electrical power supply of the at least one electric motor driving the hydraulic pumps when limiting the drive torque of the hydraulic pumps, it is ensured that the hydraulic pumps cannot draw so much drive torque from the electric motor that the electrical supply system for driving the truck-mounted concrete pump is overloaded. This is because an electric motor driving a hydraulic pump, which suddenly requires a high drive or torque when driving a work device, may suddenly consume a very large amount of current that the drive system of the truck-mounted concrete pump cannot provide, thus overloading the electrical supply.

[0016] Advantageously, the sum of the drive torques of the at least one first boom hydraulic pump and the at least one concrete pump hydraulic pump is limited such that the available electrical supply power of the electric motors driving the hydraulic pumps is not exceeded.

[0017] According to a preferred embodiment, in a first drive type, the at least one boom hydraulic pump and the at least one concrete pump hydraulic pump are driven by at least one electric motor and in a second drive type, the at least one boom hydraulic pump and the at least one concrete pump hydraulic pump are driven by an internal combustion engine, the method comprising the steps:

[0018] - Determine the drive type,

[0019] - Limiting the drive torque of the boom hydraulic pump only in the first drive type. Taking the drive type into account has the advantage that when the hydraulic pumps are driven by an internal combustion engine, the full, unlimited power of the hydraulic pumps can be used to drive the working equipment of the truck-mounted concrete pump. With electric drive, however, the drive torque(s) are limited on the hydraulic side to avoid overloading the limited electrical supply of the electric motor(s) that drive the hydraulic pumps.

[0020] Advantageously, when starting the at least one boom hydraulic pump and / or the at least one concrete pump hydraulic pump, the drive torque of the hydraulic pumps is limited more than during ongoing operation. The greater limitation of the drive torque during start-up ensures that no immediate overload occurs when starting a work device. Through fine adjustment during ongoing operation of the work device, the drive torque limitation can be reduced if necessary to drive the work device with greater power.

[0021] Advantageously, each of the at least one boom hydraulic pump and / or the at least one concrete pump hydraulic pump is assigned a power measuring unit that measures the current drive torque of the hydraulic pumps. By measuring the drive torque with a power measuring unit, which is achieved, for example, by measuring the hydraulic pressure and the volume flow at the hydraulic pump output, the drive torque can be limited more precisely, ensuring that the maximum possible power is always available to drive a work device.

[0022] According to an advantageous embodiment, the electrical power consumption of the at least one drive motor embodied as an electric motor is recorded and compared with the available electrical supply power of the at least one electric motor, and the drive torque of the at least one boom hydraulic pump or at least one concrete pump hydraulic pump driven by the at least one electric motor is limited such that the electrical power consumption of the at least one electric motor is lower than or equal to the available electrical supply power. By recording the electrical power consumption of the electric motor, it is possible to set the drive torque limitation even more precisely, so that the maximum possible power is always available for the operation of the work equipment driven by the hydraulic pumps.

[0023] A preferred embodiment provides that the truck-mounted concrete pump is supplied with electrical drive energy from a construction site power supply and has an additional power supply from a rechargeable battery with a variable charge level, whereby the drive torque of the hydraulic pumps is limited depending on the charge level of the rechargeable battery. This has the advantage that, especially when the rechargeable battery is at a high charge level, the limitation of the drive torque of the hydraulic pumps can be reduced because the risk of overloading the construction site power supply is low if the local energy storage device can contribute to the power supply of the electric motors, particularly to cover power peaks.

[0024] Further features, details, and advantages of the invention will become apparent from the following description and from the drawings, which show exemplary embodiments of the invention. Corresponding objects or elements are provided with the same reference numerals in all figures. They show:

[0025] Figure 1 Truck-mounted concrete pump according to the invention,

[0026] Figure 2 Drive system according to the invention in a first

[0027] embodiment,

[0028] Figure 3 Drive system according to the invention in a second

[0029] embodiment, and

[0030] Figure 4 Drive system according to the invention in a third

[0031] Embodiment. Figure 1 shows a truck-mounted concrete pump 100 according to the invention with a drive system according to the invention, or a truck-mounted concrete pump 100 operated according to the method according to the invention. The truck-mounted concrete pump 100 comprises a truck 102 driven by a truck combustion engine 103, having a chassis 104 on whose frame 105 a concrete pump body 101 is arranged. The concrete pump body 101 essentially comprises a concrete pump substructure

[0032] 106 with a support 107 with hydraulically driven support cylinders 108 and foldable or extendable support beams 109, as well as a hydraulically driven two-cylinder thick-matter pump 116 for pumping concrete. The concrete pump substructure 106 carries at its rear end a feed hopper 117 for liquid fresh concrete, into which an agitator 118 stirs the fresh concrete, which may, for example, be poured from a truck mixer. A hydraulically driven thick-matter changeover valve 119, for example in the form of a pipe switch (see Fig. 3), is arranged in the lower area of ​​the feed hopper 117. Instead of a pipe switch 119, for example an S-pipe or a so-called rock slide valve, the thick-matter changeover valve 119 could also be constructed, for example, from one or more rotary or flat slide valves.The working equipment, the two-cylinder high-density solids pump 119, together with the high-density solids changeover valve 119 and the agitator 118, form the concrete pump for conveying the concrete. The concrete pump substructure 106 also includes hydraulic pumps 121, 122, 123, and 124 (see Fig. 3) for the conventional hydraulic drive of the working equipment 107, 110, 116, 118, 119, and 136 of the concrete pump superstructure 101. The concrete pump substructure 106 is connected via a turntable 111 to a placing boom 110, the individual boom segments 112 of which are interconnected via articulated joints 113. The placing boom 110, or each of the articulated joints 113, is actuated by means of hydraulic cylinders 114 or other suitable articulated drives 114. The hydraulic pressure to drive the hydraulic cylinders 110 of the distribution boom 110 and the support.

[0033] 107 is provided by a common hydraulic pump 122, which for the sake of simplicity is referred to below as the boom hydraulic pump 122. The hydraulic pumps 121a, 121b, 123, 124 for driving the two-cylinder thick matter pump, the pipe switch 119, and for driving the agitator 118 are hereinafter collectively referred to as concrete pump hydraulic pumps. From the outlet of the feed hopper 117, or from the outlet of the thick matter changeover valve 119 arranged in the feed hopper 117, a concrete delivery line (not shown) runs along the placing boom 110, through which the fresh concrete filled into the feed hopper 117 by a truck mixer is conveyed to the placement site on a construction site.

[0034] Figure 2 shows a first embodiment of a drive system according to the invention for a truck-mounted concrete pump 100 according to the invention. In this embodiment, the concrete pump assembly 101 can be driven by both an internal combustion engine 103 and an electric motor M. This is therefore a truck-mounted concrete pump with a hybrid drive. The drive systems shown in Figures 3 and 4 also show hybrid drives. However, the drive system according to the invention is also applicable to purely electrically driven truck-mounted concrete pumps 100.

[0035] In the embodiment of Figure 2, the two concrete pump hydraulic pumps 121a and 121b drive two differential cylinders (not shown separately) of a two-cylinder slurry pump 116. The boom hydraulic pump 122 alternately drives the placing boom 110 or the support 107 via a switching device (not shown). The concrete pump hydraulic pump 123 is provided for driving the pipe switch 119 of the concrete pump, i.e., this second concrete pump hydraulic pump 123 charges a hydraulic accumulator (not shown), whose energy is then used in the working cycle of the differential cylinders of the two-cylinder slurry pump 116 to abruptly switch the pipe switch 119. The third concrete pump hydraulic pump 124 is provided for driving the agitator 118 of the concrete pump.In this exemplary embodiment, the hydraulic pumps 121a, 121b, 122, 123, 124 are coupled to form a hydraulic pump train 120 and are driven via the transfer case 132 either by the truck's internal combustion engine 103 or by the electric motor M. The electric motor M is supplied with electrical drive energy from the DC intermediate circuit 135 of the drive system by the inverter 146. The DC intermediate circuit 135 draws the electrical drive energy for the electric motor M from one or more AC / DC converters 129, which are connected via one or more power lines 145a, 145b and mains connection plugs 143a, 143b, for example, to a component power supply 142. The converter(s) 129 can, for example, consist of one or more commercially available chargers connected in parallel, such as those used for charging electrically powered passenger cars.The converter(s) 129 can provide galvanic decoupling, so that no separate transformers for galvanic decoupling are necessary. The construction site power supply 142 can, for example, have grid connections with different current intensities, for example, 32 amps, 63 amps, and 125 A at 400 V AC. Alternatively or additionally, the construction site power supply 142 can also have direct current supplies, such as those known for charging vehicles with direct current via the CCS system. Alternatively or additionally, an accumulator or a fuel cell could also be present on the construction site for the construction site power supply.Depending on the various mains connections of the component power supply 142, the mains connection plugs 143a, 143b can, if AC connections are available, be connected to mains connections of different or equal power, for example, via different mains adapters 144. For example, if two mains connections with 63 amperes are available, two 63 ampere mains adapters 144 could feed an electrical power into the DC intermediate circuit 135 that approximately corresponds to a 125 ampere connection. A 125 ampere connection provides a drive power of approximately 87 kW, which is relatively low compared to the drive power of the combustion engine 103, which is typically > 200 kW. The mains adapters 144 are coded so that the control device 137 can determine the electrical supply power available from the component power supply 142, for example, via data acquisition lines 141.Optionally, a rechargeable battery 126 can be connected to the DC intermediate circuit 135, which feeds additional electrical drive energy into the DC intermediate circuit 135, for example to absorb load peaks, but also to assemble and disassemble the truck-mounted concrete pump 100 purely in electric operation, i.e., to extend the outrigger 107 and unfold the placing boom 110. Depending on the capacity of the battery 126, it can also be used to drive the concrete pump. The battery 126 is charged, for example, via the DC intermediate circuit 135 by supplying it with electrical energy, for example, from the construction site power supply 142 or from the electric motor MG switched to generator mode. In this case, the electric motor M is driven by the combustion engine 103 via the transfer case 132.A transmission 130 for the drive is arranged on the internal combustion engine 103 and a cardan shaft 131 leads from the transmission 130 to the transfer case 132. Alternatively, a power take-off 134 (see Fig. 3) could also drive the transfer case 132.

[0036] A control device 137 is connected to an input device 138, with which a machine operator can, for example, adjust the delivery rate of the concrete pump or control the placing boom 110. The input device 138 can be permanently connected to the control device 137 and / or is designed, for example, as a radio remote control. In this exemplary embodiment, the control device 137 is connected by data acquisition lines 141 (shown in dashed lines) to the mains connection plugs 143, the converters 129, the optional accumulator 126, the inverter 146, and the

[0037] Power measuring units 127 are connected. The data acquisition lines 141 can be implemented, for example, in the form of a data bus system, for example, a CAN bus. The control device 137 can, for example, detect the electrical connection power or supply power available from the component power supply 142 using appropriately coded network adapters 144. Furthermore, the control device 137 can, for example, detect the charge level of the accumulator 126. The power measuring units 127, connected to the control device 137 via data acquisition lines 141, detect, for example, the hydraulic pressure and the volume flow at the output of the hydraulic pumps 121a, 121b, 122, 123, 124. The hydraulic volume flow can also be detected via the setting angle and the speed of the hydraulic pumps 121a, 121b, 122, 123, if these are designed, for example, as axial piston pumps with a swash plate.The control device 137 can determine the drive torque currently applied to drive the hydraulic pumps 121a, 121b, 122, 123, 124 via the volume flow and the output pressure, if necessary by estimating the power loss of the hydraulic pumps 121a, 121b, 122, 123, 124. Not all hydraulic pumps have to be connected or equipped with corresponding power measuring units 127. In the event that a hydraulic pump is designed as a constant flow pump, for example as a gear pump, in this embodiment the hydraulic pump 124 driving the agitator 118, its drive torque can under certain circumstancesbe assumed to be constant or, in comparison to the usually much more powerful hydraulic pumps 121a, 121b for driving the two-cylinder thick matter pump 11, it can be regarded as negligible or it can be determined from the difference between the instantaneous electrical supply power of the electric motor M and the known drive torques of the hydraulic pumps 121a, 121b, 122, 123. The drive torque of a constant flow pump, such as the agitator pump 124 here, can, for example, also be limited to a defined maximum drive torque via a pressure relief valve, so that the drive torque is limited even without an active or dynamic limitation of the drive torque of the constant flow pump 124, which is not easily possible. A variable limitation of the maximum drive torque of a constant flow pump could also be achieved via a proportionally controlled pressure relief valve.

[0038] The control device 137 is connected to the inverter 146 via a control line 139 (shown in dotted lines) and controls the electric motor M via this line. The electric motor M draws the electrical supply power for driving the hydraulic pumps 121a, 121b, 122, 123, 124 via the inverter 146 from the DC intermediate circuit 135. During the switching operations of the two-cylinder thick matter pump 116 or the pipe switch 119, or in the event of a blockage in the conveying line or a blockage of the pipe switch 119 in the feed hopper, it is possible that the current consumption of the electric motor M increases sharply due to a greatly increased hydraulic backpressure, which causes a high drive torque in the hydraulic pumps 121a, 121b, 119, which can lead to the inverter 146 being switched off via an internal safety circuit or to the converter 129 or the component power supply 142 being overloaded and overload fuses being triggered.Limiting the drive torque of the hydraulic pumps 121a, 121b, 119 thus ensures, in particular, that a certain drive torque cannot be exceeded and thus that no overload can occur on the electrical drive side. The available electrical supply power of the electric motor M therefore depends, in particular, on the available component power supply 142, whereby the optionally provided accumulator 126 can also absorb power peaks if it is sufficiently charged. If a powerful power supply is available via the component power supply 142, the inverter 146, for example, can also be the limiting factor for the available electrical supply power of the electric motor M, and it must be ensured that the inverter 146 is not overloaded.To prevent this, the control device 137 is connected via control lines 139, for example a data bus connection, to drive torque limiters 128, which in this exemplary embodiment are assigned to the hydraulic pumps 121a, 121b, 122, 123 and via which the drive torque of the hydraulic pumps 121a, 121b, 122, 123 can be limited. The drive torque limiters 128 can be designed, for example, as hydraulic or electro-hydraulic controllers of the hydraulic pumps 121a, 121b, 122, 123. In the drive system according to the invention, the drive torque of at least one hydraulic pump 121a, 121b, 122, 123, 124 is limited depending on the available electrical supply power of the electric motor M.Because the control device 137 has access to all data on the available electrical supply power of the electric motor M, which, as explained above, depends on various factors, the control device 137 can limit the drive torque of at least one hydraulic pump 121a, 121b, 122, 123, 124 in such a way that no shutdown or damage to the drive system occurs. Ultimately, fine control must be achieved to an actual electrical value, meaning that no massive torque or drive torque peaks may occur. The optional accumulator 126 helps compensate for short-term peaks in current consumption. If no accumulator 126 is present or it is discharged, the drive torques must be limited as precisely as possible from the outset, because a massive peak in the drive torque of even one hydraulic pump can lead to the drive system coming to a standstill.Instead of the accumulator 126 or in addition to the accumulator 126, another electrical energy storage device, for example a supercapacitor or the like, can be provided, which, although it has a low capacity, can absorb and release electrical energy very quickly depending on the situation.

[0039] In the embodiment of Figure 2, the electric motor M drives at least two hydraulic pumps 121a, 121b, 122, 123, 124, and the drive torques of the at least two hydraulic pumps 121a, 121b, 122, 123 are limited such that the sum of the drive torques of the at least two hydraulic pumps 121a, 121b, 122, 123, 124 does not exceed the available electrical supply power of the at least one electric motor M. In addition, fine adjustment in limiting the drive torques of the hydraulic pumps 121a, 121b, 122, 123 can be made by controlling the voltage of the DC link 135 and / or the torque of the electric motor M.

[0040] The drive torques of the individual hydraulic pumps 121a, 121b, 122, 123 can be limited interdependently. For example, the drive torques of the boom hydraulic pumps 122 and any existing fixed-displacement pumps (bypass pump, cooler, etc.) can be added together, resulting in the drive torque still available for the hydraulic pumps 121a, 121b without overloading the drive system.

[0041] Conversely, in particular, the drive torque of the concrete pump hydraulic pumps 121a, 121b, 123, 124 can be added together, resulting in the drive torque still available for the mast hydraulic pump 122, to which the mast hydraulic pump is then limited accordingly.

[0042] The drive system is configured to limit the drive torque of the hydraulic pump 121a, 121b, 122, 123, 124 driving this work device 107, 110, 116, 118, 119, 136 more strictly at the start of operation than during ongoing operation of the work devices 107, 110, 116, 118, 119, 136. The reason for this is that at the start of operation of a work device, in particular when commissioning the two-cylinder thick matter pump 116, it is difficult to estimate which drive torque is necessary for its operation and how high the power consumption of the electric motor M will then be. Therefore, the drive torque, in particular of the hydraulic pumps 121a, 121b, is initially limited more strictly than necessary.After the two-cylinder slurry pump 116 has been started, the control device 137 can record all necessary data, in particular regarding the electrical supply to the electric motor M, as explained above, and, if necessary, reduce the limitation of the drive torque of individual or all hydraulic pumps 121a, 121b, 122, 123, so that the concrete pump structure 101 can be operated at maximum possible power. In this case, a certain reserve in the electrical supply power of the electric motor M may need to be provided. By providing at least one hydraulic pump 121a, 121b, 122, 123 with a

[0043] Power measuring unit 127 is assigned, which detects the current actual drive torque of the hydraulic pumps 121a, 121b, 122, 123, an even more precise limitation of the drive torque of the hydraulic pumps 121a, 121b, 122, 123 can be carried out.

[0044] The actual electrical power consumption of the electric motor M can be detected by the control device 137, for example, using the inverter 146, and compared with the available electrical supply power. The drive torque of the hydraulic pumps 121a, 121b, 122, 123 driven by the electric motor M can then be limited such that the electrical power consumption of the electric motor M is lower than or equal to the available electrical supply power.

[0045] In this embodiment, the drive torque of the hydraulic pump 122, which drives the placing boom 110 or the support 107, is sensibly limited more during operation of the concrete pump, because during operation of the concrete pump generally only slow movements of the placing boom 110 are necessary, so that the hydraulic pumps 121a, 121b, which drive the two-cylinder thick matter pump 116, have unlimited drive torque available during the concrete delivery process, or more drive torque can be allocated which is not required for driving the placing boom 110.

[0046] The charging speed at which the hydraulic accumulator (not shown) for switching the pipe switch 119 is charged with hydraulic oil from the hydraulic pump 123 between switching operations depends on the thick matter delivery rate specified, for example, via the input device 138. If the specified thick matter delivery rate is low, the delivery pistons of the two-cylinder thick matter pump 116 move correspondingly more slowly and the time between switching operations is correspondingly longer. Therefore, the charging speed for the hydraulic accumulator can be adjusted accordingly by adjusting the power of the hydraulic pump 123, so that the hydraulic accumulator is always only filled shortly before switching. By doing this, the hydraulic pump 123 does not rhythmically withdraw more power than necessary from the drive system due to unnecessarily short charging operations.In addition, a maximum drive torque of the hydraulic pump 123 can be specified via the drive torque limiter 128, for example depending on the available electrical supply power.

[0047] Figure 3 shows a drive system according to the invention for a truck-mounted concrete pump 100 in a second embodiment.

[0048] The essential difference between the first and second embodiments of the drive system according to the invention is that the hydraulic pump train 120 in the second embodiment is divided into two separate hydraulic pump trains 120a and 120b. The first hydraulic pump train 120a has the hydraulic pumps 121a and 121b for driving the two-cylinder thick matter pump 116 and the hydraulic pump 122 for driving the distribution boom 110 and the support 107. This first hydraulic pump train 120a can, as in the first embodiment, be driven either by the internal combustion engine 103 or by an electric machine MG, which then operates as an electric motor.When the first hydraulic pump train 120a is driven by the internal combustion engine 103, the electric machine MG is operated as a power generator in that the electric machine MG, like the hydraulic pumps 121a, 121b, 122, is driven by the internal combustion engine 103 via the power take-off shaft 133. The electric machine MG is preferably arranged behind the hydraulic pumps 121a, 121b, 122 from the perspective of the internal combustion engine 103. However, the electric machine MG could also be arranged between the internal combustion engine 103 and the hydraulic pumps 121a, 121b, 122 or between the hydraulic pumps 121b and 122.The advantage of arranging the electric machine MG behind the hydraulic pump train 120a is, in particular, that for the electrical operation of the hydraulic pump train 120a, the two hydraulic pumps 121a and 121b intended for driving the two-cylinder sludge pump 116 can be decoupled from one another by a mechanical decoupling 140, for example, a clutch or a freewheel. When the hydraulic pump train 120a is operated with the internal combustion engine 103, greater drive power is available than with electrical operation, and both hydraulic pumps 121a, 121b are driven jointly when the mechanical coupling 140 is closed and can drive the two-cylinder sludge pump 116 with a relatively large drive power available from the internal combustion engine.In electric mode, the drive power, i.e., the electrical supply power of the electric machine MG operating as an electric motor, is comparatively low, and the two hydraulic pumps 121a and 121b are mechanically decoupled from each other, so that the electric machine MG only drives the hydraulic pump 122 for the placing boom 110 or the support 107, as well as the hydraulic pump 121b for driving the two-cylinder thick matter pump 116 of the concrete pump. This prevents the two hydraulic pumps 121a and 121b from operating in a partial load range due to the lower drive power in electric mode, which is associated with relatively low efficiency for hydraulic pumps, especially axial pumps with swash plates.The drive power of the electric motor MG, in conjunction with the electrical supply power, is designed so that the hydraulic pump 121b can be operated with good efficiency in the highest possible load range. Because the available drive power in electric operation is already lower than when operated with a combustion engine, it is entirely sufficient to drive the two-cylinder slurry pump 116 with just one hydraulic pump 121b.

[0049] The hydraulic pump train 120b includes the hydraulic pump 123 for driving the thick matter switching valve 119 of the concrete pump and the hydraulic pump 124 for driving the agitator 118 of the concrete pump. Additional hydraulic pumps could follow, for example, for driving a hydraulic oil cooler, a water pump, a high-pressure cleaner, etc., which are not shown for reasons of clarity. The hydraulic pump train 120b is driven both by the combustion engine 103 when driving the concrete pump assembly 101 and by an electric motor M during electrical operation.When operating the concrete pump assembly 101 with the combustion engine 103, where no component power supply 142 is available, the electric machine MG operating in generator mode, in particular, provides the electrical supply power for driving the electric motor M by feeding the electrical power generated by the electric machine MG into the DC link 135 via the inverter 146a. The accumulator 126 can then additionally be charged from the DC link 135, or the accumulator 126 can be used to absorb excess power generated by the electric machine MG.If another electrical energy storage device, such as a supercapacitor, is used instead of or in addition to the accumulator 126, it can also absorb and release electrical power for short periods of time, so that, for example, the power output of the generator MG does not have to be constantly adjusted to the power consumption of the electric motor M. During electric operation, i.e., when a component power supply 142 is available or the optional accumulator 126 can feed sufficient electrical supply power into the DC link 135, both hydraulic pump trains 120a and 120b are driven electrically. In electric operation, the electric mesh MG operates as an electric motor and is therefore also referred to below as the electric motor MG for this electric operation.In this second exemplary embodiment, two electric motors M, MG, which can be driven with different available electrical supply powers, are provided for driving the hydraulic pumps 121a, 121b, 122, 123, 124. In this exemplary case, the different available electrical supply powers are defined by the available component power connections (125A / 63A / 32A) and, if appropriate, combinations thereof, in conjunction with the electrical supply power of the optionally present accumulator 126. This means that the available electrical supply power is defined by the electrical power that can be drawn from the DC link 135 for the electrical supply of the at least one electric motor M, MG.In this second exemplary embodiment, the truck-mounted concrete pump 100 is also configured for a first operating state in which the placing boom 110 or the support 107 is in operation and the concrete pump 116, 118, 119 is not in operation, or for a second operating state in which the placing boom 110 or the support 107 and the concrete pump 116, 118, 119 are in operation. The operating state of the truck-mounted concrete pump 100 is determined and the drive torque of the boom hydraulic pump 122 is limited in the second operating state, so that the maximum possible power is available for concrete delivery, particularly during the concrete delivery process of the concrete pump. However, the placing boom 110, which is only moved slowly during concrete delivery anyway, can still be moved.However, this also means, in particular conversely, that the drive torque of the boom hydraulic pump 122 is not necessarily limited in the first operating state and thus the process of supporting the truck-mounted concrete pump 100 and folding and unfolding the placing boom 110 can be carried out with the maximum possible power when the concrete pump is at a standstill.

[0050] In order to ensure that the electrical power consumed by the electric motors M, MG does not exceed the total available electrical supply power, in this exemplary embodiment the drive torques of the hydraulic pumps 121a, 121b, 122, 123 driven by the two electric motors M, MG are limited such that the sum of the drive torques of the hydraulic pumps 121a, 121b, 122, 123 does not exceed the available electrical supply power of the two electric motors M, MG.

[0051] In this second exemplary embodiment, the entire electrical supply power available via the DC intermediate circuit 135 is distributed among the two electric motors M, MG, which are controlled via the inverters 146a and 146b. It should be noted that the available electrical supply power can also be defined or limited via the inverters 146a and 146b, respectively. This means that the DC intermediate circuit 135 could, under certain circumstances, provide a larger electrical supply power for one of the electric motors MG, M, but due to the limited power of the inverters 146a and 146b, this power cannot be passed on to the motors MG and M without overloading the inverters 146a and 146b, respectively, because this could lead to an undesired shutdown of the inverters 146a and / or 146b.For this reason, the drive torque of the hydraulic pumps 121a, 121b, 122, 123 must always be limited so that the inverters 146a and 146b do not enter an overload state.

[0052] Ultimately, depending on the design of the drive system, the available electrical connected load is always the lowest common denominator of the component power supply 142, the converter(s) 129, the DC link 135, and the inverter(s) 146. This means, for example, that if a component power supply 142 with a high electrical supply load is available, the electrical supply load that limits the drive torque of one or more hydraulic pumps 121a, 121b, 122, 123 can still be defined via the inverter(s) 146, which should not be overloaded.

[0053] In this exemplary illustration, a hydraulic oil tank 125a is assigned to the hydraulic pump train 120a, from which the hydraulic pumps 121a, 121b, 122 draw hydraulic oil. A separate hydraulic oil tank 125b is assigned to the hydraulic pump train 120b. The hydraulic pump trains 120a and 120b, but in particular the hydraulic pump train 120b that is not coupled to the combustion engine 103, can thus be arranged very flexibly on the concrete pump structure 101 without the need for long, complex hydraulic hoses to connect all hydraulic pumps to a single hydraulic oil tank 125. Of course, both hydraulic pump trains 120a and 120b can also draw the hydraulic oil required for the drive from a common hydraulic oil tank 125.

[0054] Figure 4 shows a drive system according to the invention for a truck-mounted concrete pump 100 in a third embodiment.

[0055] The hydraulic pump train 120a together with the electric machine MG is constructed identically to the embodiment shown in Figure 3 and is therefore not described separately again.

[0056] In contrast to the embodiment of Figure 3, there is no second hydraulic pump train 120b in Figure 4; instead, the hydraulic pumps 123, 124, and 147 are driven separately by electric motors M1, M2, and M3. This embodiment also shows a hydraulically driven fan 136 for a hydraulic oil cooler, which is driven by the hydraulic pump 147, with the hydraulic pump 147 being driven by the electric motor M1. The hydraulic pumps 121a, 121b, 122, and 147 use a common hydraulic oil tank 125a, while the hydraulic pumps 123 and 124 draw the hydraulic oil for operating the work devices 118, 119, and 136 from the separate hydraulic oil tank 125b. However, all hydraulic pumps could also use a common hydraulic oil tank 125, or multiple hydraulic tanks could be assigned to the hydraulic pumps in a different way.

[0057] In this third exemplary embodiment, the hydraulic pumps 121a / 121b, 122, and 123 are equipped with power measuring units 127 to determine the respective drive torque of these hydraulic pumps. For the hydraulic pumps 124 and 127, which are fixed-displacement pumps (i.e., non-controllable), no power is determined; instead, a constant drive torque is assumed, for example. The hydraulic pumps 121a / 121b, 122, and 123 are equipped with drive torque limiters 128. In electrical operation, when the electric machine MG operates as an electric motor and only drives the hydraulic pumps 121b and 122, the drive torque limiter 128 on the hydraulic pump 121a is not active because the hydraulic pump 121a is already decoupled via the clutch 140.

[0058] In the embodiments of the invention shown in Figures 2 to 4, the available electrical supply power of the at least one electric motor M, MG, M1, M2, M3 is determined and the drive torque of the at least one hydraulic pump 121a, 121b, 122, 123, 124 is limited as a function of the available electrical supply power of the at least one electric motor M, MG, M1, M2, M3.

[0059] The electrical design of the drive system presented in connection with Figures 2, 3 and 4, comprising one or more converters 129, a DC intermediate circuit 135 and the inverters 146a, 146b, 146c, 146d controlling the at least one electric motor M, M1, M2, M3, has the particular advantage that power peaks occurring when driving the units 116, 107 / 110, 118, 119, 136, which are not absorbed by limiting the drive torque of the at least one hydraulic pump 121a, 121b, 122, 123, 124, 136, cannot lead to an overload of the component power supply 142. This is particularly the case if the converter(s) 129 limit the power consumption of the component power supply 142.The maximum power available from the construction site power supply 142 via the individual power connector(s) 143 can be specified, for example, in the converter(s) 129 via an input device 138 or, as described above, via coded power adapters 144. The converter(s) 129 then only draw enough electrical power from the construction site power supply 142 via the power connector(s) 143 to prevent the construction site power supply 142 from being overloaded.If the electric motor(s) MG, M1, M2, M3 should in total draw more electrical power from the DC intermediate circuit 135 than is supplied to the DC intermediate circuit 135 by the converter(s) 129 limiting the electrical power, this can only lead to a short-term reduction in the voltage in the DC intermediate circuit 135 until the power consumption of the electric motors MG, M1, M2, M3 is again within the scope of the available electrical supply power by limiting the drive torques of the hydraulic pumps 121a, 121b, 122, 123, 124, 147 or by another form of relief of the hydraulic pumps 121a, 121b, 122, 123, 124, 147, for example by releasing a blockage in the concrete conveyance. A targeted control of the electric motor(s) MG, M1, M2, M3 via the inverter(s) 146a, 146b, 146c, 146d to limit the power consumption is therefore not necessary.

[0060] In the event that one of the higher-priority working devices 107, 110, 116, 118, 119, 136, for example the concrete pump 116, requires a higher power or drive torque when pumping the concrete pump 116, the drive torque of one or more of the other working devices 107, 110, 118, 119, 136 can be reduced, for example for a limited time, so that more drive power or drive torque is available for the higher-priority working device without limiting the drive torque. The prioritization of the drives can be assigned dynamically and, for example, defined differently when the placing boom 110 is the only drive than during the concrete delivery process, in which the concrete pump 116 and the placing boom 110 are in operation simultaneously. This can, for example, resolve a blockage of the agitator 118 by specifically focusing the power on the hydraulic pump 124 driving the agitator 118.

[0061] It would also be possible, for example, to reduce the drive torque for the placing boom 110 to a maximum even when the concrete pump 116 and the placing boom 110 are operating simultaneously, as long as there is no movement request for the placing boom 110. This means, for example, that the joysticks for controlling the placing boom 110 on a remote control are not deflected. This allows the maximum possible drive torque to be assigned to the concrete pump 116 even during the concrete delivery process. As soon as a movement of the placing boom 110 is initiated, for example by deflecting a joystick on a remote control, the permissible drive torque of the boom hydraulic pump 122 can be slightly increased and the drive torque of the concrete pump hydraulic pump 121 can be slightly reduced. The adjustment of the drive torque of the boom hydraulic pump 122 can also depend on the boom segment 112 to be moved.For example, to control the first boom segment 112, which requires a relatively high drive torque, more drive torque can be released to the boom hydraulic pump 122 than when moving only the last boom segment 112, which is significantly lighter and requires less drive torque. The drive torque limit of the concrete pump hydraulic pump can then be adjusted accordingly so that the total power does not exceed the maximum power.

[0062] Otherwise, for the third embodiment of Figure 4, as for the second embodiment of Figure 3, the electric machine MG operates as a generator when driving the concrete pump structure 101 with the internal combustion engine 103 and provides the electrical supply power for driving the electric motors M1, M2 and M3, if necessary in conjunction with the accumulator 126.

[0063] It should also be noted that the available electrical supply power is temporally variable or can also be deliberately varied over time. For example, if the mains connection plug 143, the mains adapter 144, or the power cable 145 is wound up on a cable drum, for example, because the component power supply 142 is not far away, and limiting factors due to possible overheating are present, a higher drive torque for the hydraulic pumps 121a, 121b, 122, 123, 124, 147 could nevertheless be released for a limited period of time than during continuous operation. It would also be possible to measure the operating temperature of the electrical components or their cooling, if they are cooled by a cooling circuit. As soon as a critically high temperature is detected, the drive torques of individual or all hydraulic pumps 121a, 121b, 122, 123, 124, 147 are more severely limited in order to cool the components.

[0064] The limitation of the hydraulic pump drive torque presented here should not be confused with the power control of the hydraulic pumps. For example, the power of hydraulic pump 122 is controlled via a load-sensing circuit during operation of the distribution boom 110, because the hydraulic pressure at the output of this hydraulic pump must be constantly adjusted to the distribution boom 110 and its position and can, for example, vary between 0 and 300 bar. Limiting the drive torque of the hydraulic pump then leads, for example, to a slower movement of the distribution boom 110 by reducing the volume flow while simultaneously maintaining hydraulic oil pressure to hold the distribution boom 110 in its position.

[0065] The invention has been presented here only in connection with hybrid drives, but it is understood that the invention presented here can also be applied, in particular, to purely electrically driven truck-mounted concrete pumps.

[0066] In summary, it can be stated that the intelligent limitation of the drive torque of the hydraulic pumps presented here enables a very stable drive system for a truck-mounted concrete pump 100, which cannot be jeopardized by sudden load peaks on the electrical drive side.

[0067] 100 truck-mounted concrete pumps

[0068] 101 Concrete pump construction

[0069] 102 Truck 103 Truck combustion engine

[0070] 104 chassis

[0071] 105 truck frames

[0072] 106 Concrete pump substructure

[0073] 107 Support 108 Support cylinder

[0074] 109 support beams

[0075] 110 Distribution boom

[0076] 111 turntable

[0077] 112 mast arm segments 113 articulated joint

[0078] 114 Articulated joint drive

[0079] 116 Two-cylinder thick matter pump of the concrete pump 117 Feed hopper

[0080] 118 Concrete pump agitator

[0081] 119 Thick matter switching valve (pipe switch) of the concrete pump

[0082] 120 hydraulic pump train

[0083] 121a,b Hydraulic pump Two-cylinder thick matter pump

[0084] 122 Hydraulic pump mast / support

[0085] 123 Hydraulic pump changeover valve / pipe switch

[0086] 124 Hydraulic pump agitator

[0087] 125 hydraulic oil tank

[0088] 126 accumulator

[0089] 127 Power measurement unit

[0090] 128 Drive torque limitation

[0091] 129 AC / DC converters

[0092] 130 Gearbox Drive

[0093] 131 Cardan shaft wheel drive

[0094] 132 transfer case

[0095] 133 Power take-off shaft (PTO)

[0096] 134 Gearbox power take-off (N MV) 135 DC link

[0097] 136 fans

[0098] 137 Control device

[0099] 138 Input device

[0100] 139 Control line

[0101] 140 Mechanical decoupling

[0102] 141 Data acquisition line

[0103] 142 component power supply

[0104] 143 mains connector

[0105] 144 power adapters

[0106] 145 power line

[0107] 146 inverters

[0108] 147 Hydraulic pump fan

[0109] M; M1 ; M2; M3: electric motors

[0110] MG: Electric motor / generator

Claims

Patent claims 1. A method for driving a truck-mounted concrete pump (100), wherein the truck-mounted concrete pump (100) comprises - at least one boom hydraulic pump (122) with a limitable drive torque, which is provided for driving a distribution boom (110) and / or a support (107) of the truck-mounted concrete pump (100), - at least one concrete pump hydraulic pump (121a, 121b, 123, 124) intended to drive a concrete pump (116, 118, 119) of the truck-mounted concrete pump (100), - wherein the truck-mounted concrete pump (100) is set up for a first operating state in which the distribution boom (110) or the support (107) is in operation and the concrete pump (116, 118, 119) is not in operation and, - wherein the truck-mounted concrete pump (100) is configured for a second operating state in which the distribution boom (110) or the support (107) and the concrete pump (116, 118, 119) are in operation, - the procedure comprising the following steps: - Determine the operating status of the truck-mounted concrete pump (100), - Limiting the drive torque of the mast hydraulic pump (122) in the second operating state.

2. Method for driving a truck-mounted concrete pump (100) according to claim 1, wherein the truck-mounted concrete pump (100) further comprises at least one electric motor (M, MG, M1, M2, M3) drivable with different available electrical supply powers for driving the at least one boom hydraulic pump (122) and the at least one concrete pump hydraulic pump (121a, 121b) and the Drive torque of the at least one concrete pump hydraulic pump (121a, 121b) can be limited, the method comprising the further steps: - Determining the available electrical supply power of at least one electric motor (M, MG, M1), - Limiting the drive torque of the at least one boom hydraulic pump (122) and the at least one concrete pump hydraulic pump (121a, 121b) depending on the available electrical supply power of the at least one electric motor (M, MG, M1).

3. Method for driving a truck-mounted concrete pump (100) according to claim 2, wherein the sum of the drive torques of the at least one boom hydraulic pump (122) and the at least one concrete pump hydraulic pump (121a, 121b, 123, 124) is limited such that the available electrical supply power of the electric motors (M, MG, M1) driving the hydraulic pumps (121a, 121b, 122, 123, 124) is not exceeded.

4. A method for driving a truck-mounted concrete pump (100) according to claim 1 or 2, wherein in a first drive type, the at least one boom hydraulic pump (122) and the at least one concrete pump hydraulic pump (121a, 121b, 123, 124) are driven by at least one electric motor (M, MG, M1) and in a second drive type, the at least one boom hydraulic pump (122) which drives the distribution boom (110) and / or the support (110) and the at least one concrete pump hydraulic pump (121a, 121b, 123, 124) are driven by an internal combustion engine (103), the method comprising the steps: - Determine the drive type - Limiting the drive torque of the mast hydraulic pump (122) only in the first drive mode.

5. Method for driving a truck-mounted concrete pump (100) according to one of the preceding claims, characterized in that when starting the at least one boom hydraulic pump (122) and / or the at least one concrete pump hydraulic pump (121a, 121b, 123, 124), the drive torque of the hydraulic pumps (121a, 121b, 122, 123, 124) is limited more strongly than during ongoing operation.

6. Method for driving a truck-mounted concrete pump (100) according to one of the preceding claims, wherein the at least one boom hydraulic pump (122) and / or the at least one concrete pump hydraulic pump (121a, 121b, 123, 124) is / are each assigned a power measuring unit (127) which detects the instantaneous drive torque of the hydraulic pumps (121a, 121b, 122, 123, 124).

7. A method for driving a truck-mounted concrete pump (100) according to one of claims 2 to 6, wherein the electrical power consumption of the at least one drive motor designed as an electric motor (M, MG, M1) is recorded and compared with the available electrical supply power of the at least one electric motor (M, MG, M1), and the drive torque of the at least one boom hydraulic pump (122) or at least one concrete pump hydraulic pump (121a, 121b, 123, 124) driven by the at least one electric motor (M, MG, M1) is limited such that the electrical power consumption of the at least one electric motor (M, MG, M1) is lower than or equal to the available electrical supply power.

8. Method for driving a truck-mounted concrete pump (100) according to one of the preceding claims, wherein the truck-mounted concrete pump (100) is supplied with electrical drive energy from a construction site power supply (142) and has an additional power supply from an accumulator (126) with a variable charge state, wherein the drive torque of the hydraulic pumps (121a, 121b, 122) is limited depending on the charge state of the accumulator (126).

9. Drive system for a truck-mounted concrete pump (100) with - at least one boom hydraulic pump (122) with a limitable drive torque, which is provided for driving a distribution boom (110) and / or a support (100) of the truck-mounted concrete pump (100), - at least one concrete pump hydraulic pump (121a, 121b, 123, 124) which is provided for driving a concrete pump (116, 118, 119) of the truck-mounted concrete pump (100), wherein the truck-mounted concrete pump (100) is set up for a first operating state in which the distribution boom (110) or the support (107) is in operation and the concrete pump (116, 118, 119) is not in operation and, - wherein the truck-mounted concrete pump (100) is set up for a second operating state in which the distribution boom (110) or the support (107) and the concrete pump (116, 118, 119) are in operation, characterized in that that in the second operating state the power of the at least one mast hydraulic pump (122) is limited.

10. Truck-mounted concrete pump (100) with drive system according to claim 9.

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