Patent Description:
From <CIT> a paver is known that comprises a primary driving aggregate with a combustion engine, particularly a diesel engine, and functional units with hydraulic pumps, which are driven from a crankshaft of the combustion engine. <CIT> relates to a paver with a hydraulic drive for a drive axle comprising an adjustable pump and hydraulic drives for working devices, such as conveyors, material distributors, screeds, vibrators and alike. <CIT> describes a hydraulic paver system for operating a paver in different modes, i. a transporting mode and a paving mode, wherein a first and a second hydraulic circuits are controlled independently from each other.

For different operation modes of pavers, it is known to provide different operation speeds of hydraulic pumps of a hydraulic paver system. This is usually realized by an internal combustion engine in combination with a transfer gearbox. However, the output speeds of the gearbox are permanently dependent on the input speed provided at the gear box from the internal combustion engine. This results in hydraulic losses in the hydraulic paver system, as each pump of the hydraulic system of the paver runs at the set speed requested by the highest consumer function of the hydraulic paver system. Thus, improvements of hydraulic paver systems are needed.

An object of the invention is to provide a hydraulic paver system, an electric paver, a method, a control unit, a computer program, and a computer readable medium to overcome the disadvantages outlined above. In particular, an object of the invention is to provide a hydraulic paver system, an electric paver, a method, a control unit, a computer program, and a computer readable medium that provides an increased efficiency when operating a paver to construct road surfaces.

According to a first aspect of the invention, the object is achieved by a hydraulic paver system according to claim <NUM>.

The hydraulic paver system is configured for operating an electric paver in different operation modes. The operation modes are at least a transporting mode and a paving mode that is different to the transporting mode.

In the transporting mode the hydraulic paver system and, thus, the electric paver is operated without conducting paving operations. Such paving operations typically comprise but are not limited to operating the hopper, conveying paving material required for constructing the road surface along the direction of travel of the electric paver, distributing the paving material perpendicular to the direction of travel or operating the screed device of the electric paver. In the transporting mode, the hydraulic paver system is configured to be operated to drive the electric paver from a first position to a second position without paving, i.e. without conducting paving operations. For example, the hydraulic paver system may operate the electric paver in the transporting mode to unload the electric paver from a truck and to drive the electric paver to the place of the construction site where the road surface construction is to start. In another example, the hydraulic paver system may operate in the transporting mode in order to drive the electric paver to and on the truck after having finished the road surface construction. Finally, in a further example, the hydraulic paver system may operate in the transporting mode to drive the electric paver to a parking position or to drive the electric paver from a parking position to the place of the construction site where the road surface construction is to start. In all of these examples, the paver is driven between different locations without conducting paving operations.

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

To operate the electric paver in these different operation modes, the hydraulic paver system comprises a first hydraulic circuit and a second hydraulic circuit, which can be controlled independently of each other. In particular, the first hydraulic circuit can be controlled separate from the second hydraulic circuit. Mainly, the first hydraulic circuit is provided as drive system for driving the paver between two positions and the second hydraulic circuit is provided as drive system for actuating the paving operations.

Operating the hydraulic paver system and, thus, the electric paver in these different operation modes enables to reduce hydraulic losses and, in turn, enables to increase efficiency of the hydraulic paver system and, thus, the electric paver. This is realized as will be described in the following.

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. For example, the at least one driving device is some kind of hydraulic motor. For example, the first hydraulic pump arrangement may comprise at least one fixed displacement pump and/or at least one variable displacement pump and/or at least one screw pump and/or alike.

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. Preferably, the first hydraulic pump arrangement is coupled to the first electric motor unit in a material-locking and/or form-fitting and/or force-fitting manner. In particular, by coupling the first hydraulic pump arrangement to the first electric motor unit, the speed of the first hydraulic pump arrangement is proportional to the speed of the first electric motor unit. Most preferably, a gearbox between the first electric motor unit and the first hydraulic pump arrangement is not provided. In this case, the speed of the first hydraulic pump arrangement corresponds to the speed of the first electric motor unit. It may alternatively be preferred that a gearbox between the first electric motor unit and the first hydraulic pump arrangement is provided.

The first electric motor unit may be a synchronous or asynchronous motor.

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. For example, the at least one working device is some kind of actuation device, for example an auger device and/or a cylinder device and/or a conveyor device and/or alike. For example, the second hydraulic pump arrangement may comprise at least one fixed displacement pump and/or at least one variable displacement pump and/or at least one screw pump and/or alike.

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. Preferably, the second hydraulic pump arrangement is coupled to the second electric motor unit in a material-locking and/or form-fitting and/or force-fitting manner. In particular, by coupling the second hydraulic pump arrangement to the second electric motor unit, the speed of the second hydraulic pump arrangement is proportional to the speed of the second electric motor unit. Most preferably, a gearbox between the second electric motor unit and the second hydraulic pump arrangement is not provided. In this case, the speed of the second hydraulic pump arrangement corresponds to the speed of the second electric motor unit. It may alternatively be preferred that a gearbox between the second electric motor unit and the second hydraulic pump arrangement is provided.

The second electric motor unit may be a synchronous or asynchronous motor.

Further, the hydraulic paver system comprises a control unit that is signalling coupled with the first hydraulic circuit and the second hydraulic circuit. Preferably, the control unit is or comprises a microprocessor with a memory and signalling inputs and signalling outputs. In particular, the control unit may be a personal computer or may be provided remote on a server.

The control unit is configured for operating the electric paver in the different operation modes depending on an operation mode selection input. The operation mode selection input may be provided by the user. For example, the user may select a desired operation mode via a touch screen or a button or alike, which may represent the operation mode selection input. Preferably, depending on the operation mode selection input, the control unit is configured to activate and/or deactivate the first hydraulic circuit and/or activate and/or deactivate the second hydraulic circuit. In particular, the control unit is configured to automatically activate and/or automatically deactivate the first hydraulic circuit and/or automatically activate and/or automatically deactivate the second hydraulic circuit depending on the operation mode selection input. Further preferably, the control unit is configured to activate and/or deactivate the first hydraulic circuit and/or activate and/or deactivate the second hydraulic circuit by default depending on the operation mode selection input.

In the transporting mode the first hydraulic circuit is activated and the second hydraulic circuit is deactivated. Preferably, independent on whether the hydraulic paver system and, thus, the electric paver is operated in transporting mode or paving mode, the first hydraulic circuit is activated automatically by default for driving the electric paver from a first position to a second position. In particular, the activated first hydraulic circuit is equivalent to a first hydraulic circuit that is turned on. Preferably, if the first hydraulic circuit is activated, the first hydraulic pump arrangement is driven by the first electric motor unit. In particular, if the first hydraulic circuit is activated, the first electric motor unit is turned on and running with a speed and, accordingly, the first hydraulic pump arrangement is turned on and running depending on the first electric motor unit.

It is to be understood that, preferably, if the hydraulic paver circuit is operated in the transporting mode, the second hydraulic circuit is deactivated, in particular turned off, by default. However, it may be preferred that second hydraulic circuit is activated manually in the transporting mode. For example, the second hydraulic circuit may be switched on manually by the user of the electric paver in the transporting mode. Preferably, in the transporting mode, the second electric motor unit and/or the second hydraulic pump arrangement is deactivated. It is to be understood that in the transporting mode, it may be preferred that the second electric motor unit is switched to a second electric generator unit and functions as a generator. In particular, in the transporting mode, when the second hydraulic circuit is deactivated, the second electric motor unit may function as an electric generator unit. If the second electric motor unit is switched to a second electric generator unit, the second electric motor unit does not provide any hydraulic power for the working devices. Rather, the working devices provide hydraulic power, which is transferred in the second electric generator unit into electricity.

In the transporting mode, the deactivated second hydraulic circuit provides a hydraulic standby power that is smaller than the hydraulic working power provided in the paving mode by the second hydraulic circuit. It may be preferred that the hydraulic standby power is zero. It is to be understood that if the second hydraulic circuit provides a standby power of zero, the deactivated second hydraulic circuit is equivalent to a second hydraulic circuit that is turned off. In particular, in the transporting mode, where the second electric motor unit functions as a second electro generator unit, the second electric motor unit does not provide any power for driving the working devices but consumes and, thus, transfers hydraulic power into electric power. Thus, in that regard, the standby power is understood to be negative when the second electric motor unit functions as the second electro generator unit, which is driven by the working devices.

By providing the first hydraulic pump arrangement in the first hydraulic circuit and by providing the second hydraulic pump arrangement in the second hydraulic circuit, a higher range of workings speeds is enabled independent on the different working scenarios. In particular, providing this first hydraulic circuit and this second hydraulic circuit allows to activate and/or deactivate the respective first and/or second electro motor unit and, thus, the respective hydraulic pump arrangements, which leads to reduced losses due to circulation of hydraulic fluid in the first and second hydraulic circuit.

Further, as the functions are divided up into the first and second hydraulic circuit, the speed of the first and second electro motor unit and, thus, of the first and second hydraulic pump arrangement may be controlled independent from each other, which further reduces hydraulic losses.

According to a preferred embodiment of the hydraulic paver system it is provided that in the paving mode the first hydraulic circuit is activated and the second hydraulic circuit is activated. Preferably, the second hydraulic circuit is turned on automatically by default if the hydraulic paver system and, thus, the electric paver is operated in paving mode. Additionally or alternatively, in the transport mode, it is provided that 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.

This preferred embodiment allows to deactivate, in particular turn off, any hydraulic circuits that are not needed. Deactivating or turning off the respective hydraulic circuits that comprise working devices that are not needed for a certain operation mode allows to reduce or stop hydraulic losses at the respective hydraulic pump arrangement.

Further in a preferred embodiment of the hydraulic paver system it is provided that 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 preferably 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 preferably in the deactivated second hydraulic circuit the second electric motor unit is deactivated.

In another preferred embodiment of the hydraulic paver system, the first hydraulic circuit comprises at least one driving circuit, preferably two driving circuits, wherein the at least one driving circuit comprises at least one pump, preferably at least two pumps, 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.

According in another preferred embodiment of the hydraulic paver system, 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. Additionally or alternatively, it is further preferred that the at least one driving circuit comprises two variable displacement pumps, which are connected in parallel.

In yet a further preferred embodiment of the hydraulic paver system, 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, preferably a fixed displacement 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, preferably a fixed displacement 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 preferably, the at least one tamper circuit and the at least one cooling circuit are the same circuit.

In particular, by this preferred embodiment it is ensured that sufficient flow for the cooling circuit is ensured, even though the second hydraulic pump arrangement is deactivated.

Further, according to another preferred embodiment of the hydraulic paver system, the pump or the pumps of the first hydraulic pump arrangement are coupled to the first electric motor unit, wherein preferably, the pumps of the first hydraulic pump arrangement that are coupled to the first electric motor unit, are connected in parallel.

According to a further preferred embodiment of the hydraulic paver system 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 of the electric paver, wherein preferably, the paving material is conveyed in or against the direction of travel, 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 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.

Additionally or alternatively, the second hydraulic circuit comprises at least one hydraulic working circuit, preferably at least two hydraulic working circuits, 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:.

According to yet another preferred embodiment of the hydraulic paver system, it is provided that the at least one cylinder circuit comprises a pump, preferably a variable displacement pump, and/or the at least one conveyor circuit comprises a pump, preferably a fixed displacement pump, the at least one auger circuit comprises a pump, preferably a fixed displacement pump, wherein preferably, 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.

Further, according to a preferred embodiment of the hydraulic paver system, 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 preferably, 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.

Yet according to a further preferred embodiment of the hydraulic paver system it is provided that the first hydraulic circuit comprises at least one hydraulic driving device, preferably two hydraulic driving devices, 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.

According to a further preferred embodiment of the hydraulic paver system, 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 preferably, a share of the hydraulic fluid is forwarded to the tank through the cooling device and/or through a filtering device.

This preferred embodiment has the particular advantage that no additional pump for circulating the hydraulic fluid within the respective hydraulic circuit is needed for cooling purposes.

Further, according to a preferred embodiment of the hydraulic paver system, 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 pump 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 preferably, 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 pump 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 preferably, a share of the hydraulic fluid is forwarded to the tank unit through the cooling device and/or through the filtering device,
According to a further aspect of the invention, the object is achieved by an electric paver according to claim <NUM>. The electric paver is configured for constructing a road surface. The electric paver comprises a hydraulic paver system according to the aspect and embodiments described herein.

As to the advantages, preferred embodiments and details of the electric paver, reference is made to the corresponding aspect and embodiments of the hydraulic paver system described herein above.

According to a further aspect of the invention, the object is achieved by method according to claim <NUM>. The method is for operating a hydraulic paver system and, thus, an electric paver in different operation modes according to the aspect and embodiments of the hydraulic paver system described herein.

The method comprises following steps, wherein following steps are performed by the control unit: 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.

As to the advantages, preferred embodiments and details of the method, reference is made to the corresponding aspect and embodiments of the hydraulic paver system and electric paver described herein above.

According to a preferred embodiment of the method it is provided that 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 preferably, 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.

In a further preferred embodiment of the method it is provided that 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 preferably depending on the travel speed of the electric paver and, preferably, 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.

According to a further aspect of the invention, the object is achieved by a computer program according to claim <NUM>.

As to the advantages, preferred embodiments and details of the computer program, reference is made to the corresponding aspect and embodiments of the hydraulic paver system, the electric paver, the method, and the control unit described herein above.

According to a further aspect of the invention, the object is achieved by a computer readable medium according to claim <NUM>.

As to the advantages, preferred embodiments and details of the computer readable medium, reference is made to the corresponding aspect and embodiments of the hydraulic paver system, the electric paver, the method and the computer readable medium described herein above.

Embodiments of the invention are now described below with reference to the drawings. These are not necessarily intended to show the embodiments to scale; rather, where useful for explanation, the drawings are in schematized and/or slightly distorted form. With regard to additions to the gauges directly recognizable from the drawings, reference is made to the relevant prior art. It should be borne in mind that a wide variety of modifications and changes concerning the shape and detail of an embodiment can be made without departing from the general idea of the invention. The features of the invention disclosed in the description, in the drawings as well as in the claims may be essential for the further development of the invention both individually and in any combination. In addition, all combinations of at least two of the features disclosed in the description, the drawings and/or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiments shown and described below, or limited to any subject matter that would be limited as compared to the subject matter claimed in the claims. In the case of stated design ranges, values lying within the stated limits are also intended to be disclosed as limiting values and to be capable of being used and claimed as desired. For simplicity, identical reference signs are used below for identical or similar parts or parts with identical or similar function.

<FIG> shows a vehicle <NUM> in form of an electric paver <NUM>. Although the embodiment of the invention will be described with respect to the paver, the invention is not restricted to this particular heavy-duty vehicle. The invention may also be applied in other heavy-duty vehicles with similar requirements.

As can be seen, the electric paver <NUM> comprises one screed device <NUM> having several screed units <NUM> and a hopper <NUM>.

With respect to the direction of travel T, the screed device <NUM> is arranged at the back of the electric paver <NUM> and the hopper <NUM> 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 <NUM> is arranged behind the paver <NUM> in the direction of travel T of the electric paver <NUM> and provided with the paving material stored in the hopper <NUM>. Thus, the screed device <NUM> virtually follows the paver <NUM> when a road surface is produced. The screed device <NUM> is attached to the paver by a screed attachment unit <NUM>. By means of the screed attachment unit <NUM>, the screed device <NUM> 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>. Accordingly, the screed attachment unit <NUM> is usually attached to the electric paver <NUM> by some kind of lifting device <NUM>, which is configured to lift the screed device <NUM> up in the transport position or lower it down in the paving position. Further, the screed attachment unit <NUM> allows to adjust the angle at which the screed device <NUM> rests on the surface to be produced. To achieve this, the screed attachment unit <NUM> comprises some kind of angle adjustment device <NUM>, which allows to adjust the angle at which the screed device <NUM> rests on the surface to be produced.

The two screed units <NUM> arranged in the middle, directly behind the paver <NUM>, are also known as main screed units 5a. These two main screed units 5a are swivel mounted to the screed attachment unit <NUM> in such a manner that they can swivel around a swivel axis S that extends in the direction of travel T of the paver <NUM>. 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 <NUM> for paving.

The electric paver <NUM> disclosed in <FIG> may comprise a hydraulic paver system <NUM> as described in the following with respect to the preferred embodiment of the hydraulic paver system <NUM> viewed in <FIG>.

<FIG> is a schematic circuit diagram of a preferred embodiment of the hydraulic paver system <NUM> of a paver <NUM>, for example of the paver <NUM> as shown in <FIG>. The hydraulic paver system <NUM> is configured for operating the electric paver <NUM> in different operation modes.

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

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

In the paving mode, the electric paver <NUM> is driven by means of the hydraulic paver system <NUM> from a first position to a second position whilst paving. Thus, operating the hydraulic paver system <NUM> in the paving mode means that the electric paver <NUM> 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 <NUM>.

In order to operate the hydraulic paver system <NUM> and, thus, the electric paver <NUM> at least in these two operation modes, the hydraulic paver system <NUM> comprises a first hydraulic circuit <NUM> and a second hydraulic circuit <NUM>, which can be controlled independently of each other. These two hydraulic circuits <NUM>, <NUM> are disclosed in <FIG>.

As can be seen, the first hydraulic circuit <NUM> comprises a first hydraulic pump arrangement <NUM> that is configured for providing a hydraulic driving power to at least one driving device <NUM> for driving the electric paver <NUM>. The first hydraulic pump arrangement <NUM> is coupled to a first electric motor unit <NUM>. The first electric motor unit is configured for driving the first hydraulic pump arrangement <NUM> 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 <NUM> is operated in transporting mode as well when the hydraulic paver system <NUM> is operated in paving mode.

The second hydraulic circuit <NUM> comprises a second hydraulic pump arrangement <NUM>. The second hydraulic pump arrangement <NUM> is configured for providing hydraulic working power for at least one working device of the electric paver <NUM> for paving. For this purpose, the second hydraulic pump arrangement <NUM> is coupled to a second electric motor unit <NUM>. The second electric motor unit <NUM> is configured for driving the second hydraulic pump arrangement <NUM> in the paving mode for providing the hydraulic working power required when operated in the paving mode.

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

It is to be understood that the deactivated second hydraulic circuit <NUM> 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. it is particularly preferred that in the transporting mode the second hydraulic circuit <NUM> is turned off automatically by default. In that case, if the second hydraulic circuit <NUM> is turned off the standby power is equal to zero as the second electric motor unit <NUM> is turned off and, thus, does not provide any speed and torque that would drive second hydraulic pump arrangement <NUM>.

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

In order to independently control the first hydraulic circuit <NUM> and the second hydraulic circuit <NUM>, the hydraulic paver system <NUM> comprises a control unit <NUM>. For this purpose, the control unit <NUM> is signalling coupled with the first hydraulic circuit <NUM> and the second hydraulic circuit <NUM>. The control unit <NUM> is configured for operating the electric paver <NUM> 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 <NUM> and, thus, of the electric paver <NUM>. 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.

If the first hydraulic circuit <NUM> is activated, the first electric motor unit <NUM> is driving the first hydraulic pump arrangement <NUM>. On the contrary, if the first hydraulic circuit <NUM> is deactivated, the first electric motor unit <NUM> is not driving the first hydraulic pump arrangement <NUM>. Preferably in the deactivated first hydraulic circuit <NUM> the first electric motor unit <NUM> is deactivated.

If the second hydraulic circuit <NUM> is activated, the second electric motor unit <NUM> is driving the second hydraulic pump arrangement <NUM>. On the contrary, if the second hydraulic circuit <NUM> is deactivated, the second electric motor unit <NUM> is not driving the second hydraulic pump arrangement <NUM>. Preferably in the deactivated second hydraulic circuit <NUM> the second electric motor unit <NUM> is deactivated.

From the preferred embodiment shown in <FIG> of the hydraulic paver system <NUM>, it can be seen that the first hydraulic circuit <NUM> comprises two driving circuits <NUM>. Each of the driving circuits <NUM> comprises two pumps, one variable displacement pump <NUM> and one fixed displacement pump <NUM>. These pumps <NUM>, <NUM> of the two driving circuits <NUM> are part of the first hydraulic pump arrangement <NUM>. The variable displacement pump <NUM> and the fixed displacement pump <NUM> of each driving circuit <NUM> are connected in parallel on a driving shaft that is coupled to the first electric motor unit <NUM>.

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

It is to be understood that the variable displacement pump <NUM> is part of some kind of closed loop hydraulic circuit and the fixed displacement pump <NUM> 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 <NUM> is supplied to the input side of the variable displacement pump <NUM>. The remaining share of the hydraulic fluid that has been used to drive the hydraulic driving device <NUM> is supplied to the tank unit <NUM>. In the open loop hydraulic circuit, hydraulic fluid is drawn into the stationary displacement pump <NUM> from the tank unit <NUM>.

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

Furthermore, it is preferred that the first hydraulic circuit <NUM> comprises one tamper circuit <NUM> that is at the same time a cooling circuit <NUM>, which is, thus, also called tamper-cooling circuit <NUM>. As can be seen, the tamper-cooling circuit <NUM> comprises one fixed displacement pump <NUM>. This fixed displacement pump <NUM> of the tamper-cooling circuit <NUM> is also part of the first hydraulic pump arrangement <NUM>. The fixed displacement pump <NUM> of the tamper-cooling circuit <NUM> is configured for providing a hydraulic tamping power to a tamping actuation device to actuate the tamping device <NUM> for tamping with the electric paver <NUM>. Additionally, the fixed displacement pump <NUM> of the tamper-cooling circuit <NUM> is configured for providing a hydraulic flow to a cooling device <NUM> for cooling the hydraulic fluid of the first hydraulic circuit <NUM>. The fixed displacement pump <NUM> of the tamper-cooling circuit <NUM> is connected in parallel to the remaining pumps of the first hydraulic pump arrangement <NUM> and also coupled to the first electric motor unit <NUM>.

The speed of the fixed displacement pump <NUM> of the tamper-cooling circuit <NUM> is proportional to the speed of the first electric motor unit <NUM>. Thus, the operation of the tamping device <NUM> is proportional to the speed the first electric motor unit <NUM>.

It is to be understood that in the transporting mode, the tamper device <NUM> 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 <NUM> 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. Preferably, in the paving mode, the tamper actuation device is activated automatically by default.

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

<FIG> is a schematic view of the core components of a further embodiment of the first hydraulic circuit <NUM>. Contrary to the embodiment of the first hydraulic circuit <NUM> shown in <FIG>, the first hydraulic circuit <NUM> of the embodiment shown in <FIG> comprises just one driving circuit <NUM>. It can be seen that the first hydraulic pump arrangement <NUM> is directly coupled to the first electric motor unit <NUM>. Further, <FIG> illustrates the parallel connection of the variable displacement pump and the fixed displacement pump of the driving circuit <NUM> and of the fixed displacement pump <NUM> of the tamper-cooling circuit <NUM>.

In this preferred embodiment of the hydraulic paver system <NUM> the second hydraulic circuit <NUM> comprises two hydraulic working circuits <NUM>, <NUM>.

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

In the paving mode, the other working hydraulic circuit is a so called cylinder circuit <NUM> that generates a hydraulic cylinder power as working power for the hydraulic cylinder actuation device <NUM> for lifting and extending a screed device <NUM> and its respective screed units <NUM>, 5a, 5b and for opening and for closing the hopper <NUM>.

From <FIG> it can be seen that the cylinder circuit <NUM> comprises one variable displacement pump <NUM> that is coupled to the second electric motor unit <NUM>. The conveyor circuit and the auger circuit are the same circuit <NUM> comprising two fixed displacement pumps <NUM> that are connected in parallel and coupled to the second electric motor unit <NUM>. Further, the variable displacement pump <NUM> of the cylinder circuit <NUM> is connected in parallel with the two fixed displacement pumps <NUM> of the conveyor and auger circuit <NUM>.

The second hydraulic circuit <NUM> comprises the hydraulic cylinder actuation device <NUM> wherein the hydraulic cylinder actuation device <NUM> is fluidically connected on its input side to the pump <NUM> of the cylinder circuit <NUM>, so that the pump <NUM> delivers a hydraulic fluid in the direction of the hydraulic cylinder actuation device <NUM> during operation for actuating the screed device <NUM> and hopper <NUM>. The output side of the hydraulic cylinder actuation device <NUM> is fluidically connected to the tank unit <NUM>.

Further, the second hydraulic circuit <NUM> comprises the hydraulic auger actuation device and the hydraulic conveyor actuation device <NUM>.

Both, the hydraulic auger actuation device and the hydraulic conveyor actuation device <NUM> are fluidically connected on its input side to the pumps <NUM> of the conveyor and auger circuit <NUM>. These pumps <NUM> then deliver a hydraulic fluid in the direction of the hydraulic auger actuation device and the hydraulic conveyor actuation device <NUM> 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 <NUM> is fluidically connected to the tank unit <NUM>, wherein a share of the hydraulic fluid is forwarded to the tank unit <NUM> through the cooling device <NUM> and through the filtering device <NUM>.

<FIG> is a schematic view of the core components of the second hydraulic circuit <NUM> as schematically shown in the circuit diagram of the hydraulic system <NUM> in <FIG>. The schematic arrangement of the second hydraulic circuit <NUM> shows the parallel connection of the fixed displacement pumps <NUM> of the conveyor and auger circuit and the variable displacement pump <NUM> of the cylinder circuit <NUM> that are part of the second hydraulic pump arrangement <NUM> and coupled to the second electric motor unit <NUM>.

<FIG> and <FIG> are a schematic block diagrams depicting detailed example steps for operating an electric paver according to preferred embodiments. <FIG> depicts an example embodiment for controlling the electric paver <NUM> in a transporting mode. <FIG> on the other hand depicts an example embodiment for controlling the electric paver <NUM> in a paving mode.

As disclosed in <FIG>, the method <NUM> for controlling the hydraulic paver system <NUM> of the electric paver <NUM> in transporting mode comprises several steps described in the following:
The method includes the step of determining <NUM> 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.

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 <NUM> to the respective operation mode of the electric paver <NUM>.

When operating the electric paver <NUM> 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 <NUM> and deactivating <NUM> a second hydraulic circuit <NUM>. Further, when operating the electric paver <NUM> in the transporting mode, the travel speed of the electric paver <NUM> is controlled by controlling <NUM> the speed of the first electric motor unit <NUM> and, preferably, by controlling <NUM> a stroke out of a variable displacement pump <NUM> of a driving circuit <NUM> of the first hydraulic circuit <NUM>. 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.

As disclosed in <FIG>, the method <NUM> for controlling the hydraulic paver system <NUM> of the electric paver <NUM> in paving mode comprises several steps described in the following:
As described with respect to the steps of controlling the electric paver <NUM> in transporting mode,
The method includes the steps of determining <NUM> an operation mode selection input and switching <NUM> to the respective operation mode of the electric paver <NUM> depending on the determined operation mode selection input.

When operating the electric paver <NUM> 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 <NUM> and activating <NUM> the second hydraulic circuit <NUM>. Further, when operating the electric paver <NUM> in the paving mode, the travel speed of the electric paver <NUM> is controlled as described above with respect to the control of the travel speed when the electric paver <NUM> is operated in transporting mode, i.e. by controlling <NUM> the speed of the first electric motor unit <NUM> and, preferably, by controlling <NUM> a stroke out of a variable displacement pump <NUM> of a driving circuit <NUM> of the first hydraulic circuit <NUM>.

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