DE102016221719A1 - Hydraulic control arrangement and construction machine with a hydraulic control arrangement - Google Patents

Abstract

The invention relates to a control arrangement for the energy-efficient supply of hydraulic cylinders, in particular of hydraulic differential cylinders with an oil volume flow. In this case, the volumetric flow supply can be purely displacement-controlled in an open circuit. For this purpose, the rod-side connections of all consumers can be connected to a hydraulic pump-motor unit, which can advantageously be driven by an electric machine or can emit electrical energy into an electrical intermediate-circuit memory via this electric machine. The rod-side regeneration of the oil volume flow of a consumption or multiple consumers with an active load in the rod-side cylinder chamber other parallel actuated consumers is thus also possible. By means of a respective hydraulic pump-motor unit on the bottom-side connections of the hydraulic cylinders, by setting a pressure, an equilibrium of forces on the cylinder rod can be specified in such a way that the forces opposing the desired speeds are compensated. With a summation circuit, the individual pump motor units can be interconnected.

Description

Field of the invention

The invention relates to a hydraulic control arrangement according to the preamble of claim 1. Furthermore, the invention relates to a construction machine with a control arrangement.

Background of the invention

Against the background of the steadily increasing degree of electrification of drive trains of mobile machines, an increasing desire for more efficient control systems is increasingly becoming the focus in the development of new drive and control systems for mobile machines. Today's hydraulic control systems, which are based mainly on the throttle control principle, have very large losses, especially in the partial load range and at (simultaneous) parallel operation. For cost reasons, fewer hydraulic machines, in particular in the form of pumps, are usually installed in comparison with the number of parallel controllable consumers in mobile machines. As a result, throttle losses are thus taken into account, which result from the adaptation of the different consumer pressure levels.

It is also known to provide in construction machinery, such as excavators, a hydraulic control arrangement that controls hydraulic consumers for boom, stick, bucket, slewing gear and traction drive.

To avoid the aforementioned energetic disadvantages of hydraulic control arrangements can be provided to use constant pressure systems. In this case, a variable displacement pump maintains a constant pressure in a, in particular hydropneumatic, storage. From this, the respective consumers can use according to their power requirements. As a result, a decoupling of the load, so by the consumers, and the primary energy source, ie the variable displacement, allows. A difference to the primary throttle-controlled system described at the outset is that the pressure level is now fixed, but adaptation to the respective load level is still required. In rotary hydraulic units, such as hydraulic machines, this is done without systemic energy losses by adjusting the displacement of the hydraulic machine. As a result, the output from the hydraulic machine torque can be varied, which is a so-called secondary-controlled drive. This creates a high potential for increasing the efficiency of the drive system. However, a corresponding secondary adjustment does not exist in hydraulic cylinders due to the fixed non-adjustable piston surfaces. In this case, a throttling of the accumulator pressure on the load pressure is thus required, which takes place for example via control valves. This in turn leads to energy losses described above.

For the energy-efficient control of hydraulic cylinders in a constant pressure system, a system is known which has two pressure reservoirs and thus three pressure levels: high pressure, intermediate pressure, tank. The pressure accumulator for high pressure is in this case charged by a pressure-controlled hydraulic pump with pressure medium. The pressure accumulator for intermediate or medium pressure is charged only by a return of the consumer with pressure medium. Consumers in the form of hydraulic cylinders are then operated via switching valves between these pressure levels. A remaining difference of a discrete force level and a real load force is throttled by a proportional valve. In another system for energy-efficient control of consumers in the form of hydraulic cylinders in a constant pressure system, two pressure accumulators are sequentially charged by a hydraulic pump with pressure medium. The hydraulic cylinders are operated analogously to the first described system with switching valves and a proportional valve, in particular with pressure compensators.

Due to the additional pressure level and the use of high-pressure accumulators, there is better matching of the primary-side pressure levels to the load pressure levels of the consumers, resulting in lower throttling losses, and the possibility of energy recuperation. The disadvantage here, however, is the complex circuit structure with multiple switching and proportional valves per valve segment, which is assigned to a consumer, which in turn leads to a high space requirement and high costs. Furthermore, the necessary space for the pressure accumulator of the various pressure levels is disadvantageous. It is also disadvantageous that according to a pressure vessel directive hydropneumatic pressure accumulator must be checked annually, resulting in high maintenance costs and the stoppage of the pressure accumulator starting machine.

Furthermore, systems are known in which a pure displacement control is provided in the manner of a hydrostatic transmission. As a rule, a hydraulic pump is assigned to each hydraulic consumer. Due to the principle, ideally no throttle losses occur in this system, since the volumetric flow provided by the hydraulic pump is taken up directly from the inlet side of the consumer. However, it is problematic when using consumers in the form of differential cylinders, as a arising differential volume flow must be compensated. With positive displacement controllers in a closed circuit, this can be done via additional components, such as tandem pumps or hydrotransformers. However, this in turn increases the component complexity, which leads to an increase in system costs. In addition, additional energy losses occur. As a further possibility for compensating the differential volume flow, it can be provided that the differential pressure flow is supplied to the system via a pressure accumulator on the low pressure side. The disadvantage here again proves the space-consuming and cost-increasing hydropneumatic pressure accumulator. In displacement-controlled systems, which are operated in an open circuit, the return flow is supplied to the tank.

Disclosure of the invention

In contrast, the invention has for its object to provide a control system and a construction machine with a control arrangement which is designed inexpensively and has a low space requirement.

The object with regard to the control arrangement is achieved according to the features of claim 1 and with regard to the construction machine according to the features of claim 12.

Advantageous developments of the invention are the subject of the dependent claims.

According to the invention a particular hydraulic control arrangement, in particular for a construction machine - such as an excavator - is provided, in particular for a mobile work machine, in particular for an electrified construction machine, in particular for an electrified mobile work machine. The control arrangement has at least two, in particular three, four or more hydraulic cylinders. A respective hydraulic cylinder has a piston which can be acted upon by a first pressure chamber in a first travel direction and a second pressure chamber in a second opposite travel direction with fluid or pressure medium. Advantageously, a respective second pressure chamber with a separate hydraulic machine via a respective flow path is fluidly connected. Furthermore, it is advantageous that at least one summing valve or a summing circuit is provided, can be summed with the pressure medium from at least one flow path to at least one of the other flow paths.

Thus, hydraulic machines can advantageously be interconnected in order to supply individual hydraulic cylinders with a higher volume flow. The individual hydraulic machines can thereby advantageously be made comparatively small, whereby costs and installation space can be saved. The summation is thus for example extremely advantageous in a single movement of a hydraulic cylinder.

Preferably, the pressure medium of the flow path to be summed is at least partially or approximately completely or completely summable.

Further preferably, the first pressure chambers are fluidly connected to a common hydraulic machine. With the common hydraulic machine, for example, a pressure, in particular a discharge pressure, be jointly controlled. This solution has the advantage that upon actuation of one or more hydraulic cylinders to compensate for a differential volume flow no throttle losses, as in the above-mentioned prior art occur. Furthermore, no additional components, such as tandem pumps, hydraulic transformers or hydropneumatic pressure accumulator necessary. In addition, as in the case of secondarily regulated drives, see the prior art explained above, when one or more hydraulic cylinders are actuated, one or more of the first pressure chambers displaces pressure medium directly for regeneration for another hydraulic cylinder or for recuperation in the form of electrical energy, for example in one electric cache, use, for example, by the common hydraulic machine drives a generator. In other words, compared to pure Einzelverdrängergesteuerte drives in which the hydraulic cylinders are driven by dedicated hydraulic machines, such as closed-circuit hydrostatics or tandem pumps in the open circuit, the advantage that with active loads - ie loads in a direction of travel of the hydraulic cylinder act - which can be regenerated from the first pressure chamber flowing volume directly into other controlled hydraulic cylinder. This increases the efficiency of the system, since caching in the electrical circuit is not necessary. Through the connection of the second pressure chambers with a respective hydraulic machine, a pressure in the manner that a resulting pressure force on the piston, which is composed of the pressure forces of the two pressure chambers, exactly corresponds to the opposing forces, which counteracts a movement request in the respective hydraulic cylinder , Thus, similar to secondary-regulated drives, the speed can be set or regulated via the adjustment of the resulting drive force. Furthermore, by specifying the resulting pressure forces on the piston, in particular by presetting the desired pressure by the operator, a load-sensing behavior can be set specifically. It can thus be dependent on the counter forces Set speed, the speed can decrease with increasing counter-forces, so that the operator must specify a greater target pressure, if the speed is to be maintained or increased. Such a control arrangement has improved energy efficiency. Thus, this can also be used, for example, for electrified construction machines, in which, for example, fuel cells or batteries are used as a replacement for a diesel engine drive, in which lower amounts of energy than diesel-powered construction equipment can be stored or carried.

Further advantageously no hydropneumatic pressure accumulator for displaying the function of the differential volume flow compensation is necessary by the control arrangement according to the invention. It thus eliminates the disadvantages of the pressure accumulator, which is space-consuming, costly and maintenance-intensive and requires a complex adaptation of the accumulator pressure. Furthermore, a direct regeneration of the volume flow of one or more hydraulic cylinders whose load is an active load to the first pressure chambers of the other hydraulic cylinder is possible. Furthermore account for throttle control, see the above-explained prior art, principle conditional throttle losses to adjust between a load and a pump pressure. Furthermore, it is possible in the control arrangement according to the invention that a clamping of the hydraulic cylinder is made possible during load changes, throttle losses - compared to principle-related throttle losses in throttle controls - are avoided. Furthermore, the control arrangement allows a load-sensing system behavior in the sense of open-loop (OC) system behavior control. In addition, a volume-flow-recorded system behavior, in terms of a load sensing (LS) control or a control with load-independent flow distribution (LUDV control) can be achieved. An LS control is for example from the DE 197 14 141 A1 known. Furthermore, it is advantageous that no inlet and outlet valves for heat dissipation and oil conditioning are necessary, compared to the positive displacement control in a closed circuit.

In a further embodiment of the invention, the piston of a respective hydraulic cylinder has a piston rod, wherein the respective hydraulic cylinder is formed for example as a differential cylinder. The piston rod can pass through the first pressure chamber, wherein the first direction of travel can be a retraction direction and the second direction of travel can be an extension direction of the piston rod.

Preferably, the first pressure chambers are connected to a common flow path, in particular a common pump line, to which in turn the common hydraulic machine is connected. In other words, it is proposed that the rod sides of each hydraulic differential cylinder of the main consumers be connected to a pump line. About the common connected to this line hydraulic machine, which can be designed for the entire rod side applied Eckleistung the connected consumers, the rod sides of the consumers are supplied with flow or can by this hydraulic machine with extending hydraulic cylinders with active loads, ie loads in the direction of travel (Extension direction) act, be recuperated and stored in an electrical DC link.

Advantageously, the summing valve is designed such that it connects the flow paths to be summed together.

Preferably, at least three hydraulic cylinders are provided, whose respective second pressure chamber is fluidically connected to a separate hydraulic machine via a respective flow path, at least between the first and the second flow path and between the second and the third flow path a summing valve is provided. This allows a flexible summation. For example, a summation of all three flow paths done.

In terms of apparatus technology, the summing valve can be simple or it can be a part of the summing valves or a respective summing valve can be designed as a switching valve. For example, the summing valve or a respective summing valve has a first port connected to one flow path to be summed, and a second port connected to the other flow path to be summed. Furthermore, a third connection may be provided which is connected via a first check valve to the one flow path to be summed and which is connected to the other flow path to be summed via a second check valve. The respective check valve can then open in the flow direction away from the summing valve. In a first switching position of a valve spool of the summing valve all ports can be separated from each other. In a second switching position, all connections are preferably connected to one another. The valve spool is preferably acted upon in the direction of the first switching position with a spring force of a valve spring and can be acted upon by an actuating force in the direction of the second switching position of an actuator, in particular an electromagnetically operable actuator opposite.

Alternatively or additionally, it can be provided that the summing valve or a part of the summing valves or a respective summing valve is designed as a proportional valve. The summing valve or a respective summing valve can then be arranged, for example, simply in one of the flow paths to be summed. The summing valve or a respective summing valve may have a first connection which is connected to that hydraulic machine whose flow path is to be summed. A second port may then be connected to a second pressure space of the hydraulic cylinder which is connected to the flow path to be summed. The summing valve or a respective summing valve can thus be arranged with its first and second connection in a flow path or a respective flow path. A third connection of the summing valve or a respective summing valve can then be connected to a further flow path for summing, wherein the further flow path can then be a flow path between a third pressure chamber of one of the hydraulic cylinders and the associated hydraulic machine. The summing valve or a respective summing valve preferably has a valve slide. This can be brought into first switching positions, in which preferably the first and second terminals are connected and the third terminal is blocked. Furthermore, the valve spool can be brought into second switching positions, in which the first is connected to the third port and the second port is blocked, whereby a summation of two flow paths can take place. In the direction of the first switching positions of the valve spool is preferably acted upon by the spring force of a valve spring. In the direction of the second switching positions of the valve spool with an actuating force of an actuator, in particular an electromagnetically operable actuator, be acted upon.

Advantageously, a summing valve is arranged in a respective flow path, which is connected to one of the hydromachines for the second pressure chambers.

Furthermore, it is advantageous if at least two summing valves are arranged in at least one of the flow paths formed between a hydraulic machine and a second pressure chamber. These can thus be arranged fluidly in series. The summing valves are then each connected via their third connection, each with a different flow path - which are each arranged between a hydraulic machine and a second pressure chamber - connected. Thus, pressure medium in the flow path with the at least two summing valves can be flexibly divided if necessary.

In a preferred embodiment, three hydraulic cylinders are provided, the respective second pressure chamber is fluidly connected to a separate hydraulic machine via a respective flow path, wherein in the first flow path, a first summing valve is arranged, which is connected to the second flow path. In the third flow path may be arranged a second summing valve which is connected to the second flow path. In the second flow path may be arranged a third summing valve which is connected to the first flow path. The first and second summing valves may be fluidically connected preferably between the hydraulic machine connected to the second flow path and the third summing valve. For example, the third summing valve is fluidly connected to the first flow path between the first summing valve and the hydraulic cylinder connected to the first flow path. In a further embodiment of the invention, a fourth summing valve may alternatively or additionally be provided for the third summing valve, which is arranged fluidically in the first flow path between the first summing valve and the hydraulic cylinder connected to the first flow path and which is connected to the third flow path. The fourth summing valve is then preferably connected between the second summing valve and the hydraulic cylinder connected to the third flow path. The third summing valve is preferably connected to the first flow path between the first and fourth summing valves.

In a further embodiment, each hydraulic machine of a respective second pressure chamber is advantageously assigned a drive unit or a motor, in particular an electric drive unit or electric motor. This can be used in a simple manner for a respective second pressure chamber, a respective so-called pump-motor unit. The drive units can then be driven as a generator of the respective hydraulic machine by the hydraulic machine can be used as a hydraulic motor. Furthermore, conversely, a respective drive unit can drive the respective hydraulic machine as a hydraulic pump. By means of the summation according to the invention, the individual, in particular bottom-side, pump-motor units and their inverters can thus be kept extremely small in their dimensioning. As a result, costs for material and cooling and space can be saved.

Furthermore, the drive unit or a motor, in particular an electric drive unit or an electric motor, is preferably assigned to the common hydraulic machine for the first pressure chambers. As a result, for the first pressure chambers, a so-called pump-motor unit be used. The drive unit is then drivable as a generator of the common hydraulic machine, which then acts in the form of a hydraulic motor. Conversely, the drive unit can drive the hydraulic machine as a hydraulic pump.

Preferably, a control device is provided for controlling the motors for the hydraulic machines. An inverter can then be arranged in each case between the control unit and a respective motor. The sensors of the control arrangement can furthermore be connected to the control unit.

A power supply of one or more motors or of all motors is preferably effected via at least one battery and / or one fuel cell and / or via a power supply connection, whereby electrification of the control arrangement is made possible.

Alternatively or additionally, it is conceivable to drive a hydraulic machine or a respective hydraulic machine or all hydraulic machines via at least one internal combustion engine. A respective hydraulic machine driven by an internal combustion engine is preferably pivotable.

According to the invention, a construction machine or a mobile working machine, in particular an excavator or electrified excavator, in particular an electrified mobile working machine, is provided with a control arrangement according to one or more of the preceding aspects. Such a construction machine can be electrically driven without any functional loss compared to a construction machine driven by an internal combustion engine. Preferably, one of the hydraulic cylinders is provided for a boom. Alternatively or additionally, it can be provided that one of the hydraulic cylinders is provided for a handle. Furthermore, it can alternatively or additionally be provided that one of the hydraulic cylinders is provided for a spoon. As a result, one or more of the main consumer main, such as boom, handle and spoon, energy-efficient and needs-based be supplied with an oil flow. For the boom and / or handle and / or spoon thus no direct electric drive, but these are directly driven hydraulically via the hydraulic cylinder, which in turn can be controlled by electrically driven hydraulic machines. The hydraulic cylinders have the advantage that a large power density compared to direct electrical drives is possible. Furthermore, with the hydraulic cylinder device technology simply a holding function can be implemented and the hydraulic cylinders are extremely inexpensive and robust.

Furthermore, it is alternatively or additionally conceivable that one of the hydraulic cylinders is provided for an additional consumer.

Preferably, in the construction machine a slewing gear drive and / or a traction drive is driven by an electric motor. Thus, the rotary consumers can be driven directly electrically.

A valve spool of the above and below explained valves may also be formed as a valve body, which is not a valve spool. If the valve spool is proportionally adjustable, it is conceivable that it can assume intermediate positions between its switching positions.

list of figures

• 1 in einem Schaltplan eine Steueranordnung gemäß einem ersten Ausführungsbeispiel,
• 2 in einem Schaltplan die Steueranordnung gemäß einem weiteren Ausführungsbeispiel,
• 3 in einer vergrößerten Darstellung einen Teil der Steueranordnung aus 2,
• 4 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel,
• 5 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel,
• 6 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel,
• 7 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel,
• 8 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel,
• 9 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel,
• 10 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel und
• 11 in einem Schaltplan einen Teil der Steueranordnung gemäß einem weiteren Ausführungsbeispiel.

Preferred embodiments of the invention are explained in more detail below with reference to schematic drawings. Show it:

• 1 in a circuit diagram, a control arrangement according to a first embodiment,
• 2 in a circuit diagram, the control arrangement according to a further embodiment,
• 3 in an enlarged view of a part of the control arrangement 2 .
• 4 in a circuit diagram, a part of the control arrangement according to a further embodiment,
• 5 in a circuit diagram, a part of the control arrangement according to a further embodiment,
• 6 in a circuit diagram, a part of the control arrangement according to a further embodiment,
• 7 in a circuit diagram, a part of the control arrangement according to a further embodiment,
• 8th in a circuit diagram, a part of the control arrangement according to a further embodiment,
• 9 in a circuit diagram, a part of the control arrangement according to a further embodiment,
• 10 in a circuit diagram, a part of the control arrangement according to another embodiment and
• 11 in a circuit diagram, a part of the control arrangement according to another embodiment.

According to 1 is a control arrangement 1 represented, which is used in particular for an electrified excavator. This has a common hydraulic machine 2 , which can be used as a hydraulic pump and as a hydraulic motor. The hydraulic machine 2 is output side via a central pump line 4 connected to the hydraulic cylinders 6, 8, 10 and 12. The hydraulic machine 2 is at a respective first pressure chamber 14 the hydraulic cylinder 6 to 12 connected. The hydraulic cylinders 6 to 12 are designed as differential cylinders, wherein a respective piston 16 the respective first pressure chamber 14 from a respective second pressure chamber 18 separates. A respective piston rod 20 penetrates the respective first pressure chamber 14 , which is then designed as an annulus. To a respective second pressure chamber 18 Then each another hydraulic machine 22, 24, 26 and 28 is connected.

The hydraulic machine 2 is with a drive unit 30 connected in the form of an electric machine that can be used as a motor and generator. The hydraulic machine 2 with the drive unit 30 forms a pump motor unit, either from the drive unit 30 is driven or this drives itself in generator function, depending on the resulting load case of the connected hydraulic cylinder 6 to 12 , Furthermore, the hydraulic machines 22 to 28 also each with a drive unit 32 connected in the form of an electric machine that can be used as a motor and generator. The hydraulic machines 22 to 28 then form with their respective drive unit 30 a pump-motor unit.

Furthermore, the hydraulic machines 2 and 22 to 28 each with a prestressed low pressure side 34 connected. Alternatively, it is conceivable not to design the low-pressure side biased. From the low pressure side 34 can pressure medium from the hydraulic machines 2 and 22 to 28 be promoted and it can be pressure medium over the hydraulic machines 2 and 22 to 28 be released in this.

Adjacent to the central hydraulic machine 2 is on the pump line side 4 a pressure sensor 36 intended. Furthermore, there is a respective pressure sensor 38 adjacent to a respective port of the pump line 4 to the first pressure room 14 a respective hydraulic cylinder 6 to 12 connected. The from the pressure sensor 36 detected actual pressure can then follow a predetermined by a control strategy target pressure. This actual pressure is passed through the hydraulic machine 2 with the drive unit 30 set. The hydraulic machine 2 together with the drive unit 30 is for the rod-side system cornering performance of all hydraulic cylinders 6 to 12 designed. The hydraulic machines 22 to 28 with their associated drive unit are in contrast to the central hydraulic machine 2 with its drive unit 30 only for the bottom side over the second pressure chamber 18 of the respective hydraulic cylinder 6 to 12 designed to be transmitted corner power. Furthermore, there is a respective pressure sensor 40 to a respective second pressure chamber 18 connected. About the pressure sensors 40 and 38 at the connections of the hydraulic cylinders 6 to 12 can be concluded on the cylinder pressures and thus knowing the dimensions of the hydraulic cylinder on the resulting forces and thus on the load conditions. With the knowledge of the load conditions can be calculated, whether at the hydraulic cylinders 6 to 12 a pushing or pulling load acts. This allows a pilot control of the hydraulic hydraulic machines 22 to 28 and 2 along with their drive units 30 respectively 32 in the sense of optimal system behavior. In addition, with knowledge of the actual pressure in the bottom-side second pressure chamber 18 the hydraulic cylinder 6 to 12 a set by an operating strategy respectively predetermined target pressure can be adjusted.

The following is the operation of the control arrangement 1 explained in four load cases. The listed pressure data are sample values and serve for a better understanding.

By the hydraulic cylinder 10, the system can be given a maximum load pressure. This has a passive load in the illustrated load case. That is, an external load acting on the cylinder 42 is opposite to a direction of movement direction of the hydraulic cylinder 10 directed. This is to enter after an operator request, bringing the load 40 works in the opposite direction. The self-adjusting load pressure - without bias in the second cylinder chamber 18 of the hydraulic cylinder - in the first pressure chamber 14 of the hydraulic cylinder 10 should be 200 bar. In order to compensate for pressure losses caused by lines and the hydraulic cylinder 10 to hold a pressure against, so that the speed with the hydraulic machine 26 and the associated drive unit 32 can be specified, the target pressure for adjusting the pressure in the central pump line 4 For example, an offset of 10 bar was added. The central hydraulic machine 2 together with their drive unit 30 should adjust following this target pressure. By the one with the second pressure chamber 18 hydraulic machine 26 connected to the hydraulic cylinder 10 together with its drive unit 32 the speed of the hydraulic cylinder 10 is specified. Exemplary acts in the second pressure chamber 18 of the hydraulic cylinder 10, a pressure of 5 bar to adjust the desired speed of the hydraulic cylinder 10 can. The hydraulic machine 26 operates in this case as a hydraulic motor and drives the drive unit 32 as a generator. This can then cache in an electrical intermediate circuit necessary for the bias of the hydraulic cylinder 10 energy.

The hydraulic cylinder 12 should also be retracted. However, an active load acts on it. That is, an external load 44 on the cylinder rod 20 the hydraulic cylinder 12 acts, has the same direction as the direction of movement of the hydraulic cylinder 12. Without the necessary bias of the hydraulic cylinder 12, the load pressure in the second pressure chamber 18 by way of example 50 bar. Because in the first pressure chamber 14 of the hydraulic cylinder 12, however, through the via the hydraulic machine 2 retained pressure of 210 bar, must in the second pressure chamber 18 be provided a higher pressure than the load pressure, such as 180 bar. The speed will in turn be through that with the second pressure chamber 18 the hydraulic cylinder 12 connected hydraulic machine 28 together with the drive unit 32 specified. The hydraulic machine 28 then works as a hydraulic motor and drives the drive unit 32 as a generator. This can then buffer the necessary for the bias of the hydraulic cylinder 12 energy.

The hydraulic cylinder 6 is unlike the two aforementioned hydraulic cylinders 10 and 12 are extended. Because in this case the sense of direction of the outer to the cylinder rod 20 acting load 46 is to be predetermined contrary to the sense of direction of the movement, the hydraulic cylinder 6 experiences a passive load. A pressure which is without bias of the hydraulic cylinder 6 in the second pressure chamber 18 should be set, for example, 100 bar. In order to be able to extend the hydraulic cylinder 6, the hydraulic machine 22 works together with its drive unit 32 as a hydraulic pump to a pressure, for example, 270 bar, can apply, in turn, the bias in the first pressure chamber 14 of the hydraulic cylinder 6 counteract. The drive unit connected to the hydraulic machine 22 32 thus works as a motor and takes the electrical intermediate circuit energy. The energy to be applied for overcoming the bias is in the pump line 4 to disposal. The volume flow obtained can either be used for other parallel driven-in hydraulic cylinders, such as the hydraulic cylinders 10 and 12, or he can on the hydraulic machine 2 the drive unit 30 as a generator drive. This can then feed and store energy in the electrical buffer or, for example, for the drive units 32 the hydraulic machines 22 and 24 are used.

If the case occurs that a load pressure in the second pressure chamber of the hydraulic cylinder 6 is significantly greater than the exemplary 100 bar or the pressure in the pump line 4 greater than the exemplary 200 bar, so if necessary, no sufficient pressure difference can be realized in order to extend the hydraulic cylinder 6 can. If necessary, it is then possible to slow down the speed of the consumers 10 or 6 in order to reduce their load pressures, if these depend to a large extent on the speed. Alternatively, it would be conceivable to prioritize the hydraulic cylinder 6 and to shut off the hydraulic cylinder 10. Furthermore, it would be conceivable, the first pressure chamber 14 of the hydraulic cylinder 10 from the pump line 4 For example, with a valve to disconnect and with the low pressure side 34 to connect, for example via a valve. In an advantageous embodiment, this can always be the case, for example, with passive loads and extending cylinders 6 to 12 done because the (lossy) bias in the first pressure chamber 14 deleted and this offset thus not in the form of applied energy from the hydraulic machine 22 together with its drive unit 32 must be applied.

Furthermore, the hydraulic cylinder 8 is to be extended, with an active load acting on it. That is, the sense of direction of the outer to the cylinder rod 20 acting load 48 is equal to the sense of direction of the desired movement. Without the bias due to the pressure in the pump line 4 would the load pressure in the first pressure chamber 14 of the hydraulic cylinder 8 150 bar. The hydraulic machine 24 together with its drive unit 32 this must be an additional pressure of 40 bar in the second pressure chamber 18 Apply to perform the desired movement. The drive unit 32 thus works as a motor and takes the electrical DC link energy. The energy to be applied for overcoming the bias is the central pump line 4 to disposal. The volume flow obtained can either be used for other parallel driven incoming consumers, such as the hydraulic cylinders 10 and 12, or he can the hydraulic machine 2 drive as a hydraulic motor, via the drive unit 32 in the function as generator energy can be fed and stored in the electrical intermediate circuit or for the drive units 32 the hydraulic machines 22 and 24 is available.

According to 2 is a control arrangement 50 for use in an electrified mobile work machine, especially for use in an electrified excavator. This has several valve segments 52 to 58 each a hydraulic cylinder 60 to 66 assigned. The mobile work machine can have a fully electrified powertrain. An energy supply takes place, for example, autonomously via batteries or via a fuel cell. However, it would also be conceivable to supply via a mains connection, for example via a power cable. Alternatively, it would be conceivable that the control arrangement 50 is driven by an internal combustion engine or by a plurality of internal combustion engines.

If it is assumed that a purely electrified powertrain, then it can be assumed that all rotary main consumers, such as chassis or slewing, are driven directly electrically. The main main linear consumers, such as boom, stick or spoon, can then with the control arrangement 50 energy-efficiently supplied. Hydraulic secondary consumers, such as claws or shield, can be supplied via other valve segments, such as the valve segment 58 via a central hydraulic machine 68. In addition to the central hydraulic machine 68 hydraulic machines 70, 72 and 74 are provided. The hydraulic machine 70 is the second pressure chamber 18 assigned to the hydraulic cylinder 60, which is used for a boom. The hydraulic machine 72 in turn is for the second pressure chamber 18 the hydraulic cylinder 62 is provided, which is used for a stem. Furthermore, the hydromachine 74 is for the second pressure space 18 provided the hydraulic cylinder 64 which is used for a spoon.

According to 3 the valve section 52 turns off 2 explained in more detail. This has a pressure channel 76 which is connected to the own hydraulic machine 70. Furthermore, there is a pump channel 78 provided, which is designed throughout and is connected to the central hydraulic machine 68. Furthermore, a tank channel 80 provided, which is also continuous and with the low pressure side 82 , please refer 2 , connected is. Furthermore, there are continuous pressure channels 84 and 86 provided to the other valve sections 54 and 56, see 2 to connect with their corresponding hydraulic machine 72 and 74. The valve segment 52 has a check valve 88 on, with a pressure medium connection between the pressure chambers 18 and 14 the hydraulic cylinder 60 and the hydraulic machines 68 and 70 up and is zuusteuerbar. Via a first connection is the check valve 88 with the first pressure chamber 14 and via a second connection to the second pressure chamber 18 connected. Furthermore, it is connected to the central hydraulic machine 68 via a third connection and to the hydraulic machine 70 via a fourth connection. In a first switching position of a valve slide, the terminals are separated from each other and in a second switching position is the first pressure chamber 14 with the hydraulic machine 68 and the second pressure chamber 18 connected to the hydraulic machine 70. The valve slide is biased in its closed position with a spring force of a valve spring and can be actuated in the opposite direction via an actuator. In the de-energized state of the check valve 88 Thus, the connections are separated from each other. As a result, a safe load holding function can be ensured.

In the flow path between the check valve 88 and the first pressure chamber 14 is a connection valve 90 intended. With this, the first pressure chamber 14 either with the check valve 88 or with the tank channel 80 So the low pressure side 82 get connected. The connection valve 90 is proportionally adjustable, with a valve spool in the direction of first switching positions with pressure medium of the tank channel 80 and opposite in the direction of second switching positions with pressure medium of the pressure chamber 18 is charged. Furthermore, the valve spool is acted upon in the direction of the first switching positions by a spring force of a valve spring. In the first switching positions is the first pressure chamber 14 with the shut-off valve 88 connected and in the second switching positions is the first pressure chamber 14 with the tank channel 80 connected.

With the connection valve 90 can at very high load pressures in the second pressure chamber 18 of the hydraulic cylinder 16 with acting passive loads the bias in the central pumping channel 78 be circumvented, whereby high cylinder forces are possible. Due to the proportional adjustability of the connecting valve 90 is an optimal transition behavior allows.

Furthermore, according to 3 two pressure relief valves 92 and 94 intended. The pressure relief valves 92 . 94 can perform a load protection function, which allows them to open, for example, at high load pressure peaks and a connection to the prestressed low-pressure side (tank channel 80 ) can release. The pressure relief valves 92 . 94 Additionally have a Nachsaugfunktionalität, which if necessary pressure medium from the prestressed low pressure side (Tankkanal 80 ) can be sucked in to avoid cavitation in case of load changes or movement changes.

According to 2 has the control arrangement 50 a valve segment in the form of a connection plate 96 which is arranged on the valve segment 52. These are then the hydromachines 68 to 74 connected. The connection plate 96 has as continuous channels the tank channel 80 , the pumping channel 78 , the pressure channel 76 and the pressure channels 84 and 86 on. Furthermore, in the connection plate 96 a leader line 98 with a spring-biased check valve 100 intended. The preload line 98 branches from the tank channel 80 off and is with the low pressure side 82 , which is for example a tank, connected. The check valve 100 opens in the flow direction to the low pressure side 82 , The check valve 100 serves to bias the tank channel 80 , Over the prestressed tank channel 80 are the hydraulic machines 68 to 74 supplied with pressure medium or can feed pressure medium in these, depending on the load cases. Should be from one or more of the hydraulic cylinders 60 to 66 flowing back flow of the Pressure medium is insufficient to cover a required inflow volume, is via a check valve 102 this directly from the low biased low pressure side 82 , which can be designed as a tank, sucked. The check valve 102 is between the low pressure side 82 and the hydraulic machines 68 to 74 arranged. The check valves 100 and 102 are thus arranged fluidly parallel to each other and on the one hand with the low pressure side 82 and on the other hand with the tank channel 80 connected.

According to 2 are the pressure sensors 38 and 40 provided with the second pressure chamber 18 or first pressure chamber 14 the hydraulic cylinders 60 to 64 are connected. Furthermore, the pressure sensor 36 intended. There is also a pressure sensor 104 between the check valve 102 and the hydraulic machines 68 to 74 provided, thus the pressure in the tank channel 80 taps.

The valve segments 54 and 56 are designed according to the valve segment 52, wherein in the valve segment 54 of the pressure channel 84 opens and in the valve segment 56 of the pressure channel 86 empties. As continuous channels are in the valve segments 54 and 56 of the pump channel 78 and the tank channel 80 provided to supply the last valve segment 58. The attached hydraulic cylinder 66 serves as an additional consumer. Instead of the connection valve 88 and the check valve 90 , please refer 3 , is in the valve segment 58, a control valve 106 intended. About this can then the first pressure chamber 14 and the second pressure chamber 18 alternately with either the low pressure side 82 or the central hydraulic machine 68 can be connected or the pressure medium connection can be blocked. An extension and retraction of the hydraulic cylinder 66 is thus possible. About the pressure relief valves used as load protection valves 92 and 94 with integrated Nachsaugfunktion be the pressure chambers 14 . 18 Protected against excessive load pressures and cavitation from the prestressed tank channel 80 replenishment.

The central hydraulic machine 68 is connected to the central pumping channel 78 Connected and supplies all rod-side connections of the hydraulic cylinder 60 to 66 , ie all main consumers and all secondary consumers with a pressure medium. The individual hydraulic machines 70 are with the individual pressure channels 76 . 84 and 86 connected and supply the bottom-side connections of the three hydraulic cylinders 60 to 64 as the main consumer with pressure medium.

Via the central pumping channel 78 Thus, further valve sections are supplied to control linear secondary consumers. The valve segment 58 is exemplified for this purpose.

According to 4 is a valve segment 108 as an alternative embodiment to the valve segment 52 3 shown. In contrast to 3 This is an electrically actuated connection valve 110 used to the first pressure chamber 14 the hydraulic cylinder 60 with the biased low pressure side 82 , please refer 2 , connect to. The connection valve 110 is thus instead of the pressure medium of the second pressure chamber 18 via an electromagnetic actuator 112 actuated. However, it is generally possible with passive loads of the hydraulic cylinder 60, the first pressure chamber 14 to relieve pressure and an increase in the pressure in the second pressure chamber 18 , caused by the bias pressure in the central pump channel 78 , to avoid. The overall system behavior becomes more energy efficient.

According to 5 are the hydraulic machines 68 to 74 shown, wherein the hydraulic machine 68, the drive unit 30 and the other hydraulic machines 70 to 74, respectively, the drive unit 32 assigned. The drive units 30 and 32 each have their own inverter 114 supplied with power from an electrical link, not shown here. They receive their control signals from a central control unit 116 , In this run all necessary sensor signals 118 such as from the pressure sensors 36 . 38 . 40 and 104 , and are processed and evaluated according to an operating strategy. A respective hydraulic machine 68 to 74 can be a pressure medium over the prestressed tank channel 80 suck in or depending on load cases pressure medium in this tank channel 80 feed. Should that of the hydraulic cylinders 60 to 66 , please refer 2 , backflowing pressure medium is insufficient to cover the required inflow volume flow, so can via the check valve 102 Pressure medium can be sucked directly from a less biased or unbiased central tank.

It is conceivable according to the arrangement in 5 to dispense with a variety of sensors. Will the pressure in the prestressed tank channel 80 over the pressure sensor 104 measured, see 2 , it can with knowledge of the electrical current of the drive units 30 and 32 on the engine torque and thus on the pressure difference of the respective hydraulic machine 68 to 74 getting closed. This can at least on the pressure sensors 38 , please refer 2 , be waived. About the speed of the drive units 30 and 32 Furthermore, the volumetric flows of the hydraulic machines can be determined 68 to 74 be estimated, thus predicting the speeds of the hydraulic cylinder 60 to 66 can be taken.

According to 6 is an alternative embodiment to the arrangement in 5 shown. The hydraulic machines 70, 72 and 74 are in this case over a common drive unit 120 driven. For this purpose, however, it is then necessary that at least two of the three hydraulic machines 70 to 74 are designed to be pivotable. These are according to the embodiment in 6 the hydromachines 72 and 74. Thus, these hydraulic machines have an adjustable displacement to adjust an individual volume flow can. Knowing the input speed and the intake volume of these two hydraulic machines 72 and 74, the consumer flow rates can be determined.

In 7 is another embodiment for the arrangement of the hydraulic machines 68 to 74 shown. These are common here via a drive unit 122 driven. However, for this it is necessary that three of the hydraulic machines 68 to 74 are designed to be pivotable as adjusting units in order to generate an individually adjustable volume flow can. Knowing the input speed and the displacement of these pivotable hydraulic machines 70 to 74, the consumer flow rates can be determined.

It is conceivable embodiment according to 7 Conventionally with an internal combustion engine instead of designed as an electric motor drive unit 122 together with their inverter 124 to operate. For this it is then necessary that all four hydraulic machines 68 to 74 are designed as adjusting units to set at a fixed speed of the engine all degrees of freedom of the hydraulic system can. This offers the possibility of all the advantages of the control arrangement mentioned above 50 without requiring complete electrification.

According to 8th is another embodiment of a valve segment 126 as an alternative to the valve segments 52 3 or 108 out 4 , this is a simple and inexpensive variant of a regeneration circuit, with which mainly the extension speed of the hydraulic cylinder 60 can be increased. Such a valve segment 126 For example, see also for the other hydraulic cylinders 62 and 64, see 2 be used. At the valve segment 126 is an additional regeneration valve 128 intended. The other valves 88 to 94 are according to the 3 designed. The trained as a proportional valve regeneration valve 128 can be the first pressure chamber 14 with the second pressure chamber 18 via a flow path 130 connect. For this purpose has the regeneration valve 128 a first connection with the first pressure chamber 14 is connected, and a second port connected to the second pressure chamber 18 connected is. Furthermore, it has a third port, via which it connects to the first port of the connection valve 90 connected. A valve spool of the regeneration valve 128 is acted upon in the direction of first switching positions with a spring force of a valve spring and in the direction of second switching positions via an actuator with an actuating force. In first switching positions, the first pressure chamber 14 with the connection valve 90 connected, wherein the second pressure chamber 18 is locked. In the second switching positions then the first pressure chamber 14 with the second pressure chamber 18 connected, in which case the connection to the connecting valve 90 is controlled. In intermediate positions of the regeneration valve 128 may be both part of the return flow rate at passive loads in the pumping channel 78 as well as in the inlet, so the second pressure chamber 18 , the hydraulic cylinder 60 are regenerated. The speed of the extending hydraulic cylinder 60 is mainly due to the released cross-section of the regeneration valve 128 dependent. The individually the second pressure chamber 18 hydraulic machine 72 associated with hydraulic cylinder 60, see 2 , then resembles the missing volume in the second pressure chamber 18 if this can not be compensated by suction valves.

According to 9 a further embodiment of a regeneration circuit is shown. Here is a valve segment 131 together with the hydraulic cylinder 60, a valve segment 132 and another valve segment 134 shown as end plate. The further embodiment of the control arrangement according to 9 serves to a load pressure-related return flow from the first pressure chamber 14 the hydraulic cylinder 60 for energy recovery and simultaneous regeneration in the inlet to use. Unlike the valve segment 126 out 8th has the valve segment 131 out 9 an additional line 136 that is a regeneration valve 129 with the low pressure side of the hydraulic cylinder 60 associated hydraulic machine 72 can connect. This is the line 136 via a check valve 138 of the valve segment 134 connected to the suction side of the hydraulic machine 72. The check valve 138 opens here in the flow direction to the hydraulic machine 72. Furthermore, the hydraulic machine 72 is different from 2 not directly with the check valve 102 connected but via a branch line 140 , In this is a control valve 142 arranged. This has two ports, with a first port between the check valve 138 and the hydraulic machine 72 is connected and the second connection to the check valve 102 connected. In a first switching position of a valve spool of the switching valve designed as a control valve 142 the connections are connected and disconnected in a second switching position. The valve spool of the control valve 142 is determined by the spring force of a spring and with pressure medium between the check valve 102 and the control valve 142 is tapped, acted upon in the direction of the first switching position. opposed in the direction of the second switching position, ie in the reverse direction, the valve spool is acted upon with pressure medium, which is between the check valve 138 and the regeneration valve 129 is tapped. Thus, by the additional line 136 the load pressure-related return flow of the hydraulic cylinder 60 after switching the regeneration valve 129 over the check valve 138 slammed on the suction side of the hydraulic machine 72. This can then be driven as a hydraulic motor and its associated drive unit 32 as a generator drive. Thus, the energy stored in the load-pressure return flow can be converted into electrical energy and made available to the electrical intermediate circuit. At the same time then promotes the hydraulic machine 72, the return flow in the inlet side and the second pressure chamber 18 of the hydraulic cylinder 60. A cylinder volume fraction of pressure medium can then through the pressure relief valve 92 from the prestressed tank channel 80 be sucked.

According to 9 is further in the valve segment 134 a control valve 144 intended. About this, the common hydraulic machine 68 either with the pump channel 78 or via a low pressure line 146 with the low pressure side between the check valve 102 and the hydraulic machine 68 are connected. The control valve 144 has a first port connected to the hydraulic machine 68. A second connection is with the pump channel 78 connected and a third connection with the low pressure line 146 , A valve slide can be acted upon via a valve spring in a first switching position with a spring force, in which the hydraulic machine 68 with the pumping channel 78 is connected and the connection to the low pressure line 146 Is blocked. Via an actuator of the valve spool can be actuated in a second switching position in which the hydraulic machine 68 with the low pressure line 146 is connected and the pump channel 78 is separated from the hydraulic machine 68. With the control valve 144 can thus in the second switching position pressure fluid from the hydraulic machine 68 in the prestressed tank channel 80 be encouraged. This is particularly advantageous if, for example, the hydraulic cylinder 60 is extended and in this case pressure medium from the tank channel 80 takes and the other hydraulic cylinder 62 to 66, see 2 , are not actuated. As a result, an active suction of the inlet side of the hydraulic cylinder 60 is then to its second pressure chamber 18 allows.

About the control valve 142 the suction side of the hydraulic machine 72 from the prestressed tank channel 80 be separated. If the return volume flow of the hydraulic cylinder 60 is to be regenerated during extension, the regeneration valve will be used 129 the connection of the line 136 with the prestressed tank channel 80 disconnected and a connection of the line 136 with the load pressure-bearing first pressure chamber 14 the hydraulic cylinder 60 made. For this purpose, the regeneration valve 129 according to 9 next to the connection to the first pressure chamber and the connection to the check valve 90 another connection to the tank channel 80 connected is. In addition, the regeneration valve has 129 a connection with the line 136 connected is. According to 9 is the regeneration valve 129 designed as a switching valve, wherein a valve spool is biased by the spring force of a valve spring in a first switching position. This is the first pressure room 14 with the shut-off valve 90 and the tank channel 80 with the line 136 connected. Via an actuator of the valve spool is actuated in a second switching position, in which the first pressure chamber 14 with the line 136 is connected and the other ports are locked. In the second switching position of the regeneration valve 129 can then be in the line 136 prevailing load pressure for actuating the control valve 142 are used, whereby the connection of the hydraulic machine 72 with the prestressed tank channel 80 is disconnected. Whether the return flow rate of the hydraulic cylinder 60 is to be regenerated can be determined from the signals of the pressure sensors 36 . 38 and 40 , please refer 2 , which are determined in accordance with an operating strategy by the control unit 116 , please refer 5 , are processed.

According to 10 a summation circuit for the control arrangement according to the invention is shown. This is in a valve segment 148 educated. In the valve segment are the pump channel 78 , the, in particular prestressed, tank channel 80 , the pressure channel 76 , the pressure channel 84 and the pressure channel 86 designed as continuous channels to communicate with the hydraulic cylinders 60 to 66 , please refer 2 to be connectable. In particular, the arrangement of the hydraulic machines 68 to 74 , the pressure sensors 36 . 104 and the check valves 100 . 102 corresponds to the embodiment according to 2 ,

To sum the flow paths in the form of the pressure channels 76 . 84 and 86 are two summing valves 150 . 152 intended. With the first summing valve 150 can the pressure channels 76 and 84 and with the second summing valve 152 the pressure channels 84 and 86 be summed up. The first summing valve 150 has a first with the pressure channel 76 and a second with the pressure channel 84 connected connection. A third port is via a first check valve 154 with the pressure channel 76 and a second check valve 156 with the pressure channel 84 connected. The check valves 154 . 156 open in the flow direction away from the first summing valve 150 , A valve spool of the first formed as a switching valve summing valve 150 can be brought into a first switching position and a second switching position. In the first Switching position, the terminals are separated from each other and in the second switching position all connections are connected. In the direction of the first switching position of the valve slide of a spring force of a valve spring and in the opposite direction of an actuating force of an actuator can be acted upon.

The second summing valve 152 is according to the first summing valve 150 designed. It is with its first connection to the pressure channel 84 and with its second connection to the pressure channel 86 connected. Via a first check valve 158 it is the pressure channel 84 and a second check valve 160 to the pressure channel 86 connected. The check valves 158 and 160 open in the flow direction away from the associated summing valve 152 ,

According to 10 can through the summing valve 150 the pressure channel 76 and the pressure channel 84 connected, thus the hydraulic cylinder 60, see 2 , which may be used for the boom, with the hydraulic cylinder 62, which can be used for the stem, can be fluidly connected. Thus, it is possible, for example, to supply the boom with the volume flow of the hydraulic machine 72 and thus to increase its extension speed. In this case, however, preferably the handle is not actuated in order to control the extension speed of the boom exactly. When increasing the extension speed of the stem applies accordingly. About the check valves 154 . 156 is a drainage of pressure medium from the pressure channel 76 to the pressure channel 84 and vice versa prevented.

About the summing valve 152 can the pressure channels 84 and 86 be connected, whereby a summation of the flow rates of the hydraulic machines 72 and 74 is made possible. As a result, then preferably either the hydraulic cylinder 62 for the stem, see 2 or the hydraulic cylinder 64 for the spoon are extended faster. If the stem to be extended faster, so preferably the spoon is not operated and vice versa in the faster extension of the spoon, the stem is not operated to control each controlled the extension speed can. About the check valves 158 . 160 in turn, a drainage of pressure medium from the pressure channel 84 to the pressure channel 86 and vice versa prevented.

By controlling both summing valves 150 . 152 For example, all of the individual hydraulic machines 70, 72 and 74 can be fluidly connected. In this interconnection, preferably only one of the hydraulic cylinders 60, 62 or 64, see 2 , operated to accurately control the speed of the actuated hydraulic cylinder 60, 62 or 64 can. According to 11 a further embodiment of a summing circuit is shown. In contrast to 10 is the summing circuit in the valve segment 148 designed differently to easily parallel operation of hydraulic cylinders 60, 62 and 64, see 2 to enable.

For the summing circuit is according to 11 in the pressure channel 76 a first summing valve 162 and in the pressure channel 86 a second summing valve 164 intended. Furthermore, in the pressure channel 84 a third summing valve 166 and in the pressure channel 76 another fourth summing valve 168 , The summing valves 162 to 168 are the same design and designed as proportional valves. The first summing valve 162 is with a first port and with a second port in the pressure port 76 used. There is a third connection with the pressure channel 84 connected. In the first switching positions of a valve spool of the summing valve 162 the first port and the second port are connected, bringing the pressure channel 76 is open. The third connection is blocked in the first switching positions. In second switching positions of the valve spool, the first and the third port are connected and the second port is blocked, whereby the pressure channel 76 with the pressure channel 84 connected is. The valve spool is acted upon in the direction of the first switching positions with the spring force of a valve spring and in the direction of the second switching positions with an actuating force of an actuator. The second summing valve 164 is then with its first and second connection in the pressure channel 86 used. The third port is with the pressure channel 84 connected. The third summing valve 166 is then with its first and second connection in the pressure channel 84 used. The third port is with the pressure channel 76 connected. The fourth summing valve 168 is then with its first and second connection in the pressure channel 86 used. The third port is with the pressure channel 86 connected. The third summing valve 166 is with its third connection then between the first and fourth summing valve 162 and 168 to the pressure channel 76 connected. The fourth summing valve 168 is with its third connection between the second summing valve 164 and the hydraulic cylinder 64 connected.

According to 11 are thus the pressure channels 76 . 84 and 86 in each case by the summing valves designed as proportional valves 162 to 168 connectable with each other. For example, the pressure channel 76 through the summing valve 162 with the pressure channel 84 get connected. Will the summing valve 162 fully energized in this case, consists of the hydraulic machine 70, a direct connection to the pressure channel 84 , Thus, the volumetric flows of the hydraulic machines 70 and 72 can be completely summed up and the hydraulic cylinder 62, see 2 to be provided for the stalk. Should both the hydraulic cylinder 60, see 2 , for the boom and the Hydraulic cylinder 62 are actuated in parallel for the stem and requires, for example, the hydraulic cylinder 62 a larger volume flow than the hydraulic machine 72 can promote, so the valve spool of the summation valve 162 be moved to an intermediate position in the manner that, for example, a pressure in the pressure channel 76 is accumulated in the type to a flow distribution in the individual pressure channel 84 to enable. Possible resulting throttle losses can be reduced by clamping the (extending) hydraulic cylinder with the lower load pressure at passive loads by the central hydraulic machine 68. There may be a pressure adjustment of both hydraulic cylinders 60 and 62 in the inlet by increasing the pressure in the first pressure chamber 14 , please refer 2 , the lastniederen of the two hydraulic cylinders 60 and 62 take place. Here, the first pressure chamber 14 the higher-load of the two hydraulic cylinders 60 and 62 with the, in particular biased, tank channel 80 get connected. The converted by the clamping with the hydraulic machine 68 electrical energy can be used or cached in the electrical intermediate circuit. Through the summing valves 164 . 166 and 168 can also be a connection between the individual individual pressure channels 86 . 84 and 76 be achieved. A summation of the volume flow of the actually associated with the spoon hydraulic machine 74 with the example for the hydraulic cylinder 62 (stem) required flow rate is thus possible.

The summing valves can have a modular structure, so that an individual configuration of a valve block by the end user is possible. Thus, for example, it is also conceivable that in the sense of a cost-optimal design of the control arrangement described here completely dispensed with one of the individual the bottom sides of the cylinder associated pump motor units 70, 72, 74 and the design of the volume flow to that of the remote pump assigned Consumers only via the summing valves described 162 to 168 he follows.

The invention relates to a control arrangement for the energy-efficient supply of hydraulic cylinders, in particular of hydraulic differential cylinders with an oil volume flow. In this case, the volumetric flow supply can be purely displacement-controlled in an open circuit. For this purpose, the rod-side connections of all consumers can be connected to a hydraulic pump-motor unit, which can advantageously be driven by an electric machine or can emit electrical energy into an electrical intermediate-circuit memory via this electric machine. The rod-side regeneration of the oil volume flow of a consumption or multiple consumers with an active load in the rod-side cylinder chamber other parallel actuated consumers is thus also possible. By means of a respective hydraulic pump-motor unit on the bottom-side connections of the hydraulic cylinders, by setting a pressure, an equilibrium of forces on the cylinder rod can be specified in such a way that the forces opposing the desired speeds are compensated. It is possible here to specify a desired speed (measurement of the speed on the cylinder piston or the rotational speed of the electric machine) or to set a resulting force difference (via the specification of the pressure in the cylinder bottom side). With the latter variant, a load-sensing behavior can be represented. By means of pressure sensors at the connections as well as in the pump and tank line, it is possible to determine the respective load conditions by determining the corresponding pressures and to set the necessary pressures in the cylinder chambers for clamping the cylinder. In an advantageous embodiment can be dispensed with position and the majority of pressure sensors, as can be closed on the speed difference and the electric current of the electric machines on the flow and the pump torque on the pressure difference. With a summation circuit, the individual pump motor units can be interconnected.

LIST OF REFERENCE NUMBERS

1

control arrangement

2

hydromachine

4

pump line

6 to 12

hydraulic cylinders

14

first pressure chamber

16

piston

18

second pressure chamber

20

piston rod

22 to 28

hydromachine

30

drive unit

32

drive unit

34

Low pressure side

36

pressure sensor

38

pressure sensor

40

pressure sensor

42

Lorries

44

Lorries

46

Lorries

48

Lorries

50

control arrangement

52 to 58

valve segment

60 to 66

hydraulic cylinders

68 to 74

hydromachine

76

pressure channel

78

pump channel

80

tank channel

82

Low pressure side

84

pressure channel

86

pressure channel

88

check valve

90

connecting valve

92

Pressure relief valve

94

Pressure relief valve

96

connecting plate

98

bias line

100

check valve

102

check valve

104

pressure sensor

106

control valve

108

valve segment

110

connecting valve

112

actuator

114

inverter

116

control unit

118

sensor signals

120

drive unit

122

drive unit

124

inverter

126

valve segment

128

regeneration valve

129

regeneration valve

130

flow path

131

valve segment

132

Between the valve segment

134

valve segment

136

management

138

check valve

140

branch line

142

control valve

144

control valve

146

Low-pressure line

148

valve segment

150

summing

152

summing

154

check valve

156

check valve

158

check valve

160

check valve

162

summing

164

summing

166

summing

168

summing

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19714141 A1 [0015]

Claims (12)

Control arrangement, in particular for a construction machine, with at least two hydraulic cylinders (60, 62, 64), wherein a respective hydraulic cylinder (60, 62, 64) has a piston (16), which via a first pressure chamber (14) in a first direction of travel and via a second pressure chamber (18) in a second direction of travel can be acted upon with fluid, characterized in that a respective second pressure chamber (18) with its own hydraulic machine (70, 72, 74) via a respective flow path (76, 84, 86) fluidly and at least one summing valve (150, 152; 162-168) is provided, with which the pressure medium of at least one of the flow paths (76, 84, 86) is summable to at least one other of the flow paths (76, 84, 86). Control arrangement after Claim 1 , wherein the first pressure chambers (14) are fluidically connected to a common hydraulic machine (68). Control arrangement after Claim 1 or 2 , wherein at least three hydraulic cylinders (60, 62, 64) are provided, the respective second pressure chamber (18) with its own hydraulic machine (70, 72, 74) via a respective flow path (76, 84, 86) is fluidically connected, wherein between the first and second flow paths (76, 84) and / or between the second and third flow paths (84, 86) a summing valve (150, 152) is provided. Control arrangement according to one of the preceding claims, wherein the summing valve (150, 152) or a part of the summing valves (150, 152) or a respective summing valve (150, 152) is designed as a switching valve. A control arrangement as claimed in any preceding claim, wherein the summing valve (150, 152) or a portion of the summing valves (150, 152) or a respective summing valve (150, 152) is connected to one of the flow paths (76, 84, 86) via a first port; connected via a second port to another of the flow paths (76, 84, 86) and via a third port with two in the flow direction away from the summing valve (150, 152) opening check valves (154, 156), wherein the one check valve with the one Flow path (76, 84, 86) and the other check valve with the other flow path (76, 84, 86) is connected. Control arrangement after Claim 5 , wherein a valve spool of the summing valve (150, 152) blocks the connections in a first switching position and connects the connections in a second switching position. Seoulanordnung according to one of the preceding claims, wherein the summing valve (162-168) or a part of the summing valves (162-168) or a respective summing valve (162-168) is designed as a proportional valve. A control arrangement as claimed in any one of the preceding claims, wherein the summing valve (162-168) or a portion of the summing valves (162-168) or a respective summing valve (162-168) is disposed in one of the flow paths (76,84,86) to be summed. Control arrangement after Claim 8 wherein the summing valve (162-168) is disposed via first and second ports in one of the flow paths (76, 84, 86) and connected via a third port to another flow path (76, 84, 86). Control arrangement after Claim 9 wherein a valve spool of the summing valve (162-168) in first switch positions connects the first and second ports and blocks the third port, and wherein the valve spool in second switch positions connects the first and third ports and blocks the second port. Control arrangement after Claim 10 , wherein the valve spool of the summing valve (162-168) can be brought into intermediate positions between the first and second switching positions. Construction machine with a control arrangement according to one of the preceding claims.

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