HYDRAULIC PAVER SYSTEM, A METHOD, AND A CONTROL UNIT FOR OPERATING AN ELECTRIC PAVER IN DIFFERENT OPERATION MODES, AN ELECTRIC PAVER FOR CONSTRUCTING A ROAD SURFACE, A COMPUTER PROGRAM, AND A COMPUTER READABLE MEDIUM

Abstract

A hydraulic paver system for operating an electric paver in different operation modes including a first hydraulic circuit and a second hydraulic circuit, wherein the first hydraulic circuit includes a first hydraulic pump arrangement configured for providing a hydraulic driving power to driving device(s) for driving the electric paver, and the second hydraulic circuit includes a second hydraulic pump arrangement configured for providing hydraulic working power for working device(s) of the electric paver for paving, wherein the second hydraulic pump arrangement is driven in the paving mode for providing the hydraulic working power, and a control unit for operating the electric paver in the different operation modes, wherein in the transporting mode the first hydraulic circuit is activated and the second hydraulic circuit is deactivated, wherein the deactivated second hydraulic circuit provides a hydraulic standby power that is smaller than the hydraulic working power provided in the paving mode.

Claims

1. A hydraulic paver system for operating an electric paver in different operation modes, wherein the operation modes are at least a transporting mode and a paving mode that is different to the transporting mode, and wherein the hydraulic paver system comprises: a first hydraulic circuit and a second hydraulic circuit, which can be controlled independently of each other, wherein the first hydraulic circuit comprises a first hydraulic pump arrangement that is configured for providing a hydraulic driving power to at least one driving device for driving the electric paver, wherein the first hydraulic pump arrangement is coupled to a first electric motor unit, which drives the first hydraulic pump arrangement in a transporting mode and/or in a paving mode for providing the hydraulic driving power, and the second hydraulic circuit comprises a second hydraulic pump arrangement that is configured for providing hydraulic working power for at least one working device of the electric paver for paving, wherein the second hydraulic pump arrangement is coupled to a second electric motor unit, which drives the second hydraulic pump arrangement in the paving mode for providing the hydraulic working power, and a control unit that is signalling coupled with the first hydraulic circuit and the second hydraulic circuit, wherein the control unit is configured for operating the electric paver in the different operation modes depending on an operation mode selection input, wherein in the transporting mode the first hydraulic circuit is activated and the second hydraulic circuit is deactivated, wherein the deactivated second hydraulic circuit provides a hydraulic standby power that is smaller than the hydraulic working power provided in the paving mode.

2. The hydraulic paver system according to claim 1, wherein in the paving mode the first hydraulic circuit is activated and the second hydraulic circuit is activated, and/or in the transport mode, the second hydraulic circuit is turned off, in particular turned off automatically by default, and/or the second hydraulic circuit may be turned on manually by a user.

3. The hydraulic paver system according to claim 1, wherein in the activated first hydraulic circuit the first electric motor unit is driving the first hydraulic pump arrangement, and/or in the deactivated first hydraulic circuit the first electric motor unit is not driving the first hydraulic pump arrangement, wherein in the deactivated first hydraulic circuit the first electric motor unit is deactivated, and/or in the activated second hydraulic circuit the second electric motor unit is driving the second hydraulic pump arrangement, and/or in the deactivated second hydraulic circuit the second electric motor unit is not driving the second hydraulic pump arrangement, wherein in the deactivated second hydraulic circuit the second electric motor unit is deactivated.

4. The hydraulic paver system according to claim 1, wherein the first hydraulic circuit comprises at least one driving circuit, wherein the at least one driving circuit comprises at least one pump, in particular at least one variable displacement pump and/or at least one fixed displacement pump, wherein the first hydraulic pump arrangement comprises the at least one pump of the at least one driving circuit.

5. The hydraulic paver system according to claim 4, wherein the at least one driving circuit comprises at least two pumps, in particular the variable displacement pump and the fixed displacement pump, which are connected in parallel.

6. The hydraulic paver system according to claim 5, wherein the first hydraulic circuit comprises at least one tamper circuit and/or at least one cooling circuit, wherein the at least one tamper circuit comprises a pump that is part of the first hydraulic pump arrangement, wherein the pump of the at least one tamper circuit is configured for providing a hydraulic tamping power to a tamping device for tamping with the electric paver, and/or the at least one cooling circuit comprises a pump that is part of the first hydraulic pump arrangement, wherein the pump of the at least one cooling circuit is configured for providing a hydraulic flow to a cooling device for cooling the hydraulic fluid of the first hydraulic circuit, wherein the at least one tamper circuit and the at least one cooling circuit are the same circuit.

7. The hydraulic paver system according claim 4, wherein the pump or the pumps of the first hydraulic pump arrangement are coupled to the first electric motor unit, wherein the pumps of the first hydraulic pump arrangement are coupled to the first electric motor unit, are connected in parallel.

8. The hydraulic paver system according to claim 1, wherein the working devices comprise at least one hydraulic conveyor actuation device for driving at least one conveyor device for conveying paving material along the direction of travel (T) of the electric paver, wherein the paving material is conveyed in or against the direction of travel (T), and/or at least one hydraulic auger actuation device for driving at least one auger device for distributing the paving material crosswise to the direction of travel (T) of the electric paver, and/or at least one hydraulic cylinder actuation device for lifting and/or extending a screed device of the electric paver and/or for opening a hopper and/or for closing the hopper, and/or at least one hydraulic tamper actuation device for driving at least one tamper device of the electric paver, and/or wherein the second hydraulic circuit comprises at least one hydraulic working circuit, wherein the at least one hydraulic working circuit comprises at least one pump, and/or wherein the at least one hydraulic working circuit is at least one of the following: at least one conveyor circuit that is configured for providing hydraulic conveyor power for the at least one hydraulic conveyor actuation device for driving the at least one conveyor device of the electric paver, at least one auger circuit that is configured for providing hydraulic auger power for the at least one hydraulic auger actuation device for driving the at least one auger device of the electric paver, at least one cylinder circuit that is configured for providing hydraulic cylinder power for the at least one hydraulic cylinder actuation device for lifting and/or extending the screed device of the electric paver and/or for closing the hopper and/or for opening the hopper, and at least one tamper circuit that is configured for providing hydraulic tamper power for the at least one hydraulic tamper actuation device for driving the tamper device of the electric paver, at least one vibration circuit that is configured for providing hydraulic vibration power for the at least one hydraulic vibration actuation device for driving the vibration device of the electric paver, wherein the at least one auger circuit and the at least one conveyor circuit are the same hydraulic circuit.

9. The hydraulic paver system according to claim 1, wherein the at least one cylinder circuit comprises a pump, the at least one conveyor circuit comprises a pump, and/or the at least one auger circuit comprises a pump, wherein in the case the at least one auger circuit and the at least one conveyor circuit are the same hydraulic circuit, the pumps of the at least one conveyor circuit and the at least one auger circuit are connected in parallel.

10. The hydraulic paver system according to claim 1, wherein the pump of the at least one cylinder circuit and/or the pump of the at least one auger circuit and/or the pump of the at least one conveyor circuit and/or the pump of the at least one tamper circuit are coupled to the second electric motor unit, wherein the pumps of the at least one cylinder circuit and/or of the at least one auger circuit and/or the at least one conveyor circuit and/or the pump of the at least one tamper circuit are connected in parallel.

11. The hydraulic paver system according to claim 4, wherein the first hydraulic circuit comprises at least one hydraulic driving device, wherein each hydraulic driving device is fluidically connected on their input side to the at least one pump of the at least one driving circuit, so that the pump of the respective at least one driving circuit delivers a hydraulic fluid in the direction of the hydraulic driving device during operation of the electric paver, wherein the output side of each hydraulic driving device is fluidically connected to the input side of the at least one pump of the at least one driving circuit and/or a tank unit.

12. The hydraulic paver system according to claim 6, wherein the first hydraulic circuit comprises the hydraulic tamper actuation device, wherein the hydraulic tamper actuation device is fluidically connected on its input side to the pump of the respective at least one tamper circuit, so that the pump of the respective at least one tamper circuit delivers a hydraulic fluid in the direction of the hydraulic tamper actuation device during operation of the paver, wherein the output side of each hydraulic tamper actuation device is fluidically connected to the tank unit, wherein a share of the hydraulic fluid is forwarded to the tank through the cooling device and/or through a filtering device.

13. The hydraulic paver system according to claim 1, wherein the second hydraulic circuit comprises the hydraulic cylinder actuation device, wherein the hydraulic cylinder actuation device is fluidically connected on its input side to the pump of the respective at least one cylinder circuit, so that the pump delivers a hydraulic fluid in the direction of the hydraulic cylinder actuation device during operation, wherein the output side of each hydraulic cylinder actuation device is fluidically connected to the tank unit, and/or the second hydraulic circuit comprises the hydraulic auger actuation device, wherein the hydraulic auger actuation device is fluidically connected on its input side to the pump of the respective at least one auger circuit, so that the pumps delivers a hydraulic fluid in the direction of the hydraulic auger actuation device during operation, wherein the output side of each hydraulic auger actuation device is fluidically connected to the tank unit, wherein a share of the hydraulic fluid is forwarded to the tank unit through the cooling device and/or through the filtering device, and/or the second hydraulic circuit comprises the hydraulic conveyor actuation device, wherein the hydraulic conveyor actuation device is fluidically connected on its input side to the pump of the respective at least one conveyor circuit, so that the pumps delivers a hydraulic fluid in the direction of the hydraulic conveyor actuation device during operation, wherein the output side of each hydraulic conveyor actuation device is fluidically connected to the tank unit, wherein a share of the hydraulic fluid is forwarded to the tank unit through the cooling device and/or through the filtering device.

14. An electric paver for constructing a road surface, said paver comprising a hydraulic paver system according to claim 1.

15. A method for operating an electric paver according to claim 14 in different operation modes, the method comprising following steps: determining an operation mode selection input, and switching to the respective operation mode of the electric paver depending on the determined operation mode selection input, wherein the operation modes are at least a transporting mode and a paving mode that is different to the transporting mode, and when operating the electric paver in the transporting mode providing a transporting mode actuation signal for activating a first hydraulic circuit and deactivating a second hydraulic circuit, and/or when operating the electric paver in the paving mode providing a paving mode actuation signal for activating the first hydraulic circuit and activating the second hydraulic circuit.

16. A method according to claim 15, when operating the electric paver in the transporting mode or the paving mode controlling a travel speed of the electric paver by controlling the speed of the first electric motor unit and/or if the first hydraulic circuit comprises at least one driving circuit with at least one variable displacement pump, controlling a stroke out of the at least one variable displacement pump.

17. A method according to claim 15, when operating the electric paver in the paving mode controlling a working speed of at least one working device by controlling the speed of the second electric motor unit and/or depending on the travel speed of the electric paver and, if the second hydraulic circuit comprises at least one working circuit with at least one variable displacement pump, controlling a stroke out of the at least one variable displacement pump, depending on a paving width, a paving height and the paving speed.

18. A control unit for operating an electric paver in different operation modes, wherein the control unit is configured to perform the steps of the method according to claim 15.

19. A computer program comprising program code means for performing the steps of claim 15 when said program is run on a control unit.

20. A computer readable medium carrying a computer program comprising program code means for performing the steps of claim 15 when said program is run on a control unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0063] With reference to the appended drawings, below follows a more detailed description of embodiments of the present disclosure cited as examples.

[0064] In the drawings:

[0065] FIG. 1 is a three-dimensional view of a paver in a one embodiment;

[0066] FIG. 2 is a schematic circuit diagram of an embodiment of the hydraulic paver system of a paver as shown in FIG. 1;

[0067] FIG. 3 is a schematic view of the core components of a further embodiment of the first hydraulic circuit 10; and

[0068] FIG. 4 is schematic view of the core components of the second hydraulic circuit as schematically shown in the circuit diagram of the hydraulic paver system in FIG. 2;

[0069] FIG. 5 is a schematic block diagram depicting detailed example steps for controlling a hydraulic paver system and, thus, an electric paver in a transporting mode; and

[0070] FIG. 6 is a schematic block diagram depicting detailed example steps for controlling a hydraulic paver system and, thus, an electric paver in a paving mode.

DETAILED DESCRIPTION

[0071] FIG. 1 shows a vehicle 2 in form of an electric paver 2. Although the embodiment of the present disclosure will be described with respect to the paver, the disclosed subject matter is not restricted to this particular heavy-duty vehicle. The disclosed subject matter may also be applied in other heavy-duty vehicles with similar requirements.

[0072] As can be seen, the electric paver 2 comprises one screed device 4 having several screed units 5 and a hopper 6.

[0073] With respect to the direction of travel T, the screed device 4 is arranged at the back of the electric paver 2 and the hopper 6 is arranged in the front for storing paving material required for paving in operation. For operation, i.e., to produce a road surface, the screed device 4 is arranged behind the paver 2 in the direction of travel T of the electric paver 2 and provided with the paving material stored in the hopper 6. Thus, the screed device 4 virtually follows the paver 2 when a road surface is produced. The screed device 4 is attached to the paver by a screed attachment unit 7. By means of the screed attachment unit 7, the screed device 4 can be lifted up in a transport position when not paving (not shown) or lowered down into a paving position for paving as shown in FIG. 1. Accordingly, the screed attachment unit 7 is usually attached to the electric paver 2 by some kind of lifting device 8, which is configured to lift the screed device 4 up in the transport position or lower it down in the paving position. Further, the screed attachment unit 7 allows to adjust the angle at which the screed device 4 rests on the surface to be produced. To achieve this, the screed attachment unit 7 comprises some kind of angle adjustment device 9, which allows to adjust the angle at which the screed device 4 rests on the surface to be produced.

[0074] The two screed units 5 arranged in the middle, directly behind the paver 2, are also known as main screed units 5a. These two main screed units 5a are swivel mounted to the screed attachment unit 7 in such a manner that they can swivel around a swivel axis S that extends in the direction of travel T of the paver 2. This allows adjusting the slope of the road surface. Further, it can be seen that attached to each main screed unit 5a a displaceable screed unit 5b is attached comprising respective extensions to increase the width of the paver 2 for paving.

[0075] The electric paver 2 disclosed in FIG. 1 may comprise a hydraulic paver system 1 as described in the following with respect to the embodiment of the hydraulic paver system 1 viewed in FIG. 2.

[0076] FIG. 2 is a schematic circuit diagram of an embodiment of the hydraulic paver system 1 of a paver 2, for example of the paver 2 as shown in FIG. 1. The hydraulic paver system 1 is configured for operating the electric paver 2 in different operation modes.

[0077] The operation modes are at least a transporting mode and a paving mode.

[0078] In the transporting mode, the electric paver 2 is driven by means of the hydraulic paver system 1 from a first position to a second position without paving. For example, the hydraulic paver system 1 may be run in the transporting mode to unload the electric paver 2 from a truck and to drive the electric paver 2 to the place of the construction site where the road surface construction is to start. In another example, the hydraulic paver system 1 may be run in the transporting mode in order to drive the electric paver 2 to and on the truck after having finished the road construction. Finally, in a further example, the hydraulic paver system 1 may be run in the transporting mode to drive the electric paver 2 to a parking position or to drive the electric paver 2 from a parking position to the place of the construction site where the road construction is to start. In all of these examples, the paver 2 is driven between different locations without conducting paving operations.

[0079] In the paving mode, the electric paver 2 is driven by means of the hydraulic paver system 1 from a first position to a second position whilst paving. Thus, operating the hydraulic paver system 1 in the paving mode means that the electric paver 2 is conducting paving operations whilst being driven. In the paving mode, a road surface is constructed by conducting the paving operations whilst driving the paver 2.

[0080] In order to operate the hydraulic paver system 1 and, thus, the electric paver 2 at least in these two operation modes, the hydraulic paver system 1 comprises a first hydraulic circuit and a second hydraulic circuit 20, which can be controlled independently of each other. These two hydraulic circuits 10, 20 are disclosed in FIG. 2.

[0081] As can be seen, the first hydraulic circuit 10 comprises a first hydraulic pump arrangement 11 that is configured for providing a hydraulic driving power to at least one driving device 13 for driving the electric paver 2. The first hydraulic pump arrangement 11 is coupled to a first electric motor unit 12. The first electric motor unit is configured for driving the first hydraulic pump arrangement 11 in the transporting mode as well as in the paving mode. Thus, the electric motor provides the hydraulic driving power need for both, when the hydraulic paver system 1 is operated in transporting mode as well when the hydraulic paver system 1 is operated in paving mode.

[0082] The second hydraulic circuit 20 comprises a second hydraulic pump arrangement 21. The second hydraulic pump arrangement 21 is configured for providing hydraulic working power for at least one working device of the electric paver 2 for paving. For this purpose, the second hydraulic pump arrangement 21 is coupled to a second electric motor unit 12. The second electric motor unit 12 is configured for driving the second hydraulic pump arrangement 21 in the paving mode for providing the hydraulic working power required when operated in the paving mode.

[0083] Depending on the operation mode, the first hydraulic circuit 10 and the second hydraulic circuit 20 of the hydraulic paver system 1 can be activated or deactivated. If the hydraulic paver system 1 is operated in the transporting mode, the first hydraulic circuit 10 is activated and the second hydraulic circuit 20 is deactivated by default. However, if the hydraulic paver system 1 is operated in the paving mode, both hydraulic circuits 10, 20, i.e., the first hydraulic circuit 10 and the second hydraulic circuit 20 are automatically activated by default.

[0084] It is to be understood that the deactivated second hydraulic circuit 20 provides a hydraulic standby power that is smaller than the hydraulic working power provided in the paving mode. However, it is particularly preferred, that deactivated means turned off, i.e., in the transporting mode the second hydraulic circuit 20 is turned off automatically by default. In that case, if the second hydraulic circuit 20 is turned off the standby power is equal to zero as the second electric motor unit 12 is turned off and, thus, does not provide any speed and torque that would drive second hydraulic pump arrangement 21.

[0085] Accordingly, if the first hydraulic circuit 10 is deactivated, the first hydraulic circuit 10 provides a hydraulic standby power that is smaller than the hydraulic driving power. With respect to the first hydraulic circuit 10 it is particularly preferred, that deactivated means turned off as well, i.e., that the first hydraulic circuit 10 is turned off when deactivated. In that case, if the first hydraulic circuit 10 is turned off the standby power is equal to zero as the first electric motor unit 12 is turned off and, thus, does not provide any speed and torque that would drive first hydraulic pump arrangement 11.

[0086] In order to independently control the first hydraulic circuit 10 and the second hydraulic circuit 20, the hydraulic paver system 1 comprises a control unit 30. For this purpose, the control unit 30 is signalling coupled with the first hydraulic circuit 10 and the second hydraulic circuit 20. The control unit 30 is configured for operating the electric paver 2 in the different operation modes depending on an operation mode selection input. The operation mode selection input may usually be provided by the user or driver of the hydraulic paver system 1 and, thus, of the electric paver 2. The user or driver may provide the operation mode selection input via some kind of user interface, for example a touch screen, some kind of button or alike.

[0087] If the first hydraulic circuit 10 is activated, the first electric motor unit 12 is driving the first hydraulic pump arrangement 11. On the contrary, if the first hydraulic circuit 10 is deactivated, the first electric motor unit 12 is not driving the first hydraulic pump arrangement 11. In some embodiments, in the deactivated first hydraulic circuit 10 the first electric motor unit 12 is deactivated.

[0088] If the second hydraulic circuit 20 is activated, the second electric motor unit 22 is driving the second hydraulic pump arrangement 21. On the contrary, if the second hydraulic circuit is deactivated, the second electric motor unit 22 is not driving the second hydraulic pump arrangement 21. In some embodiments, in the deactivated second hydraulic circuit 20 the second electric motor unit 22 is deactivated.

[0089] From the embodiment shown in FIG. 2 of the hydraulic paver system 1, it can be seen that the first hydraulic circuit 10 comprises two driving circuits 110. Each of the driving circuits 110 comprises two pumps, one variable displacement pump 111 and one fixed displacement pump 112. These pumps 111, 112 of the two driving circuits 110 are part of the first hydraulic pump arrangement 11. The variable displacement pump 111 and the fixed displacement pump 112 of each driving circuit 110 are connected in parallel on a driving shaft that is coupled to the first electric motor unit 12.

[0090] If the pumps of each driving circuit 110 are driven by the first electric motor unit 12, hydraulic fluid is drawn into the pumps on their input side and supplied to driving devices 13 each driving circuit 110 comprises. Each hydraulic driving device 13 is fluidically connected to the pumps of each driving circuit 110. In particular, each hydraulic driving device 13 is fluidically connected on their input side to the output side of the pumps of each driving circuit 110.

[0091] It is to be understood that the variable displacement pump 111 is part of some kind of closed loop hydraulic circuit and the fixed displacement pump 112 is part of some kind of open loop hydraulic circuit. In the closed loop hydraulic circuit a share of the hydraulic fluid that has been used to drive the hydraulic driving device 13 is supplied to the input side of the variable displacement pump 111. The remaining share of the hydraulic fluid that has been used to drive the hydraulic driving device 13 is supplied to the tank unit 3. In the open loop hydraulic circuit, hydraulic fluid is drawn into the stationary displacement pump 112 from the tank unit 3.

[0092] Thus, if the first electric motor unit 12 is activated and, thus, driven, the respective pumps that are coupled to the first electric motor unit 12 are driven accordingly depending on the speed and torque provided by the first electric motor unit 12. The driven pumps 111, 112 generate a respective flow of the hydraulic fluid that is used to drive the hydraulic driving device 13. The hydraulic driving device 13 is to be understood as some kind of hydraulic motor that may be coupled to the wheels of the electric paver 2 for driving the electric paver 2. The speed and torque of the hydraulic driving device 13 and of the wheels of the electric paver 2 and, thus, of the electric paver 2 depends on the speed and torque of the first electric motor unit 12 and on the stroke out of the variable displacement pump 111 of the driving circuit 110. It is obvious that the speed of the hydraulic driving device 13 and, thus, of the electric paver 2 may be varied by varying the speed of the first electric motor unit 12 and/or by varying the stroke out of the variable displacement pump 111.

[0093] Furthermore, the first hydraulic circuit 10 may comprise one tamper circuit 120 that is at the same time a cooling circuit 120, which is, thus, also called tamper-cooling circuit 120. As can be seen, the tamper-cooling circuit 120 comprises one fixed displacement pump 121. This fixed displacement pump 121 of the tamper-cooling circuit 120 is also part of the first hydraulic pump arrangement 11. The fixed displacement pump 121 of the tamper-cooling circuit 120 is configured for providing a hydraulic tamping power to a tamping actuation device to actuate the tamping device 18 for tamping with the electric paver 2. Additionally, the fixed displacement pump 121 of the tamper-cooling circuit 120 is configured for providing a hydraulic flow to a cooling device 16 for cooling the hydraulic fluid of the first hydraulic circuit 10. The fixed displacement pump 121 of the tamper-cooling circuit 120 is connected in parallel to the remaining pumps of the first hydraulic pump arrangement 11 and also coupled to the first electric motor unit 12.

[0094] The speed of the fixed displacement pump 121 of the tamper-cooling circuit 120 is proportional to the speed of the first electric motor unit 12. Thus, the operation of the tamping device 18 is proportional to the speed the first electric motor unit 12.

[0095] It is to be understood that in the transporting mode, the tamper device 18 can be deactivated. This may be achieved by controlling a tamper control valve, which prevents a hydraulic flow to or through the tamper actuation device in the transporting mode and, thus, prevents actuation of tamper device 18 when not needed. Thus, it may be controlled that the tamper actuation device is only activated in paving mode for tamping the paving material provided to construct the road surface. In the paving mode, the tamper actuation device is activated automatically by default.

[0096] It is to be understood that the fixed displacement pump 121 of the tamper-cooling circuit 120 is providing a flow of hydraulic fluid independent on whether the hydraulic paver system 1 or the electric paver 2 is operated in the transporting mode or the paving mode. The fixed displacement pump 121 of the tamper-cooling circuit 120 needs to run in each operation mode for cooling the hydraulic fluid that is circulated in the first hydraulic circuit 10. Thereby, at least a share of the hydraulic fluid is forwarded to the tank through the cooling device 16 and through a filtering device 17.

[0097] FIG. 3 is a schematic view of the core components of a further embodiment of the first hydraulic circuit 10. Contrary to the embodiment of the first hydraulic circuit 10 shown in FIG. 2, the first hydraulic circuit 10 of the embodiment shown in FIG. 3 comprises just one driving circuit 110. It can be seen that the first hydraulic pump arrangement 11 is directly coupled to the first electric motor unit 12. Further, FIG. 3 illustrates the parallel connection of the variable displacement pump and the fixed displacement pump of the driving circuit 110 and of the fixed displacement pump 121 of the tamper-cooling circuit 120.

[0098] In this embodiment of the hydraulic paver system 1 the second hydraulic circuit 20 comprises two hydraulic working circuits 210, 220.

[0099] In the paving mode, one of the two hydraulic working circuits 220 generates working power for a working device that is a hydraulic conveyor actuation device 15 for driving at least one conveyor device for conveying paving material along the direction of travel T of the electric paver 2 and a hydraulic auger actuation device 15 for driving an auger device for distributing the paving material crosswise to the direction of travel T of the electric paver 2. Accordingly, this hydraulic working circuit, which incorporates the auger circuit and the conveyor circuit in the same hydraulic circuit 220, is configured for providing hydraulic cylinder power and a hydraulic conveyor power for the hydraulic conveyor actuation device for driving the conveyor device of the electric paver 2 and for the hydraulic auger actuation device 15 for driving the auger device of the electric paver 2.

[0100] In the paving mode, the other working hydraulic circuit is a so called cylinder circuit 210 that generates a hydraulic cylinder power as working power for the hydraulic cylinder actuation device 14 for lifting and extending a screed device 4 and its respective screed units 5, 5a, 5b and for opening and for closing the hopper 6.

[0101] From FIG. 2 it can be seen that the cylinder circuit 210 comprises one variable displacement pump 211 that is coupled to the second electric motor unit 12. The conveyor circuit and the auger circuit are the same circuit 220 comprising two fixed displacement pumps 221 that are connected in parallel and coupled to the second electric motor unit 12.

[0102] Further, the variable displacement pump 211 of the cylinder circuit 210 is connected in parallel with the two fixed displacement pumps 221 of the conveyor and auger circuit 220.

[0103] The second hydraulic circuit 20 comprises the hydraulic cylinder actuation device 14 wherein the hydraulic cylinder actuation device 14 is fluidically connected on its input side to the pump 211 of the cylinder circuit 210, so that the pump 211 delivers a hydraulic fluid in the direction of the hydraulic cylinder actuation device 14 during operation for actuating the screed device 4 and hopper 6. The output side of the hydraulic cylinder actuation device 14 is fluidically connected to the tank unit 3.

[0104] Further, the second hydraulic circuit 20 comprises the hydraulic auger actuation device and the hydraulic conveyor actuation device 15.

[0105] Both, the hydraulic auger actuation device and the hydraulic conveyor actuation device 15 are fluidically connected on its input side to the pumps 221 of the conveyor and auger circuit 220. These pumps 221 then deliver a hydraulic fluid in the direction of the hydraulic auger actuation device and the hydraulic conveyor actuation device 15 during operation to actuate the respective auger device and conveyor device. The output side of the hydraulic auger actuation device and the hydraulic conveyor actuation device 15 is fluidically connected to the tank unit 3, wherein a share of the hydraulic fluid is forwarded to the tank unit 3 through the cooling device 16 and through the filtering device 17.

[0106] FIG. 4 is a schematic view of the core components of the second hydraulic circuit 20 as schematically shown in the circuit diagram of the hydraulic system 1 in FIG. 2. The schematic arrangement of the second hydraulic circuit 20 shows the parallel connection of the fixed displacement pumps 221 of the conveyor and auger circuit and the variable displacement pump 211 of the cylinder circuit 210 that are part of the second hydraulic pump arrangement 21 and coupled to the second electric motor unit 22.

[0107] FIGS. 5 and 6 are a schematic block diagrams depicting detailed example steps for operating an electric paver according to some embodiments. FIG. 5 depicts an example embodiment for controlling the electric paver 2 in a transporting mode. FIG. 6 on the other hand depicts an example embodiment for controlling the electric paver 2 in a paving mode.

[0108] As disclosed in FIG. 5, the method 1000 for controlling the hydraulic paver system 1 of the electric paver 2 in transporting mode comprises several steps described in the following:

[0109] The method includes the step of determining 1010 an operation mode selection input. This may step may be conducted by the user providing information on or selecting the desired operation mode. For example, the user may select on a touch screed or by means of some kind of button or alike the desired operation mode. Based on this selection the operation mode selection input is determined.

[0110] Depending on the determined operation mode selection input, i.e., for example, whether paving mode or transporting mode is determined as operation mode, the method comprises the step of switching 1020 to the respective operation mode of the electric paver 2.

[0111] When operating the electric paver 2 in the transporting mode is determined, the method comprises the step of providing a transporting mode actuation signal for activating 1030a a first hydraulic circuit 10 and deactivating 1040 a second hydraulic circuit 20. Further, when operating the electric paver 2 in the transporting mode, the travel speed of the electric paver 2 is controlled by controlling 1060 the speed of the first electric motor unit 12 and, by controlling 1070 a stroke out of a variable displacement pump 111 of a driving circuit 110 of the first hydraulic circuit 10. In that regard, a large stroke out leads to a larger flow of the hydraulic fluid and, thus, increases the travel speed further. If on the other hand, the stroke out is minimized, the flow of the hydraulic fluid is minimized and, thus, the travel speed decreased.

[0112] As disclosed in FIG. 6, the method 1000 for controlling the hydraulic paver system 1 of the electric paver 2 in paving mode comprises several steps described in the following:

[0113] As described with respect to the steps of controlling the electric paver 2 in transporting mode,

[0114] The method includes the steps of determining 1010 an operation mode selection input and switching 1020 to the respective operation mode of the electric paver 2 depending on the determined operation mode selection input.

[0115] When operating the electric paver 2 in the paving mode is determined, the method comprises the step of providing a paving mode actuation signal for activating 1030b the first hydraulic circuit 10 and activating 1050 the second hydraulic circuit 20. Further, when operating the electric paver 2 in the paving mode, the travel speed of the electric paver 2 is controlled as described above with respect to the control of the travel speed when the electric paver 2 is operated in transporting mode, i.e., by controlling 1060 the speed of the first electric motor unit 12 and by controlling 1070 a stroke out of a variable displacement pump 111 of a driving circuit 110 of the first hydraulic circuit 10.

[0116] When operating the electric paver 2 in the paving mode the method further comprises the step of controlling a working speed of at least one working device by controlling 1080 the speed of the second electric motor unit 22. In some embodiments, the speed of the second electric motor unit 22 is controlled depending on the travel speed of the electric paver 2. Further, the if the working circuit comprises a variable displacement pump 211, the working speed may also be controlled depending on the stroke out of the variable displacement pump 211. With respect to the hydraulic paver system 1 described above, the working speed of the hydraulic cylinder actuation device for actuating the screed device 4 and the hopper 6 may be varied, in addition to varying the speed of the second electric motor unit 22, by means of the variable displacement pump 211 that is part of the cylinder circuit 210. Further it is to be understood that the working speed of the second electric motor unit is not only controlled depending on the traveling speed of the electric paver 2 but also depending on a paving width and a paving height of the road surface to be constructed.

REFERENCE SIGNS

[0117] 1 hydraulic paver system [0118] 2 electric paver [0119] 3 tank unit [0120] 4 screed device [0121] 5, 5a, 5b screed units [0122] 6 hopper [0123] 7 screed attachment unit [0124] 8 lifting device [0125] 9 angle adjustment device [0126] 10 first hydraulic circuit [0127] 11 first hydraulic pump arrangement [0128] 12 first electric motor unit [0129] 13 hydraulic driving unit [0130] 14 hydraulic cylinder actuation device [0131] 15 hydraulic auger conveyor actuation device [0132] 16 cooling unit [0133] 17 filtering device [0134] 20 second hydraulic circuit [0135] 21 second hydraulic pump arrangement [0136] 22 second electric motor unit [0137] 110 driving circuit [0138] 111, 211 variable displacement pump [0139] 112, 121, 221 fixed displacement pump [0140] 120 tamper circuit [0141] 210 cylinder circuit [0142] 220 auger conveyor circuit [0143] S swivel axis [0144] T direction of travel