Attachment, vehicle combination and computer program product

Abstract

The invention relates to an attachment (67), in particular a front loader (4), and a vehicle combination (1) comprising a work vehicle (66), in particular a tractor (2), and an attachment (67). According to the invention, the attachment (67) has a hydraulic system (26) with hydraulic actuators (59), in particular a lifting cylinder (36) and a tilting cylinder (37). The attachment (67) also has an attachment bus system (27), which is preferably designed as an ISOBUS. The attachment bus system (27) has an attachment bus interface (32) which can be coupled to a work vehicle bus system (15) via a work vehicle bus interface (33). The attachment bus system (27) is coupled to pressure sensors (38, 39, 41, 42) and / or motion sensors (40, 43) such that measurement signals can be transmitted via the attachment bus system (27).Preferably, bidirectional communication and coordination of the operating states of the work vehicle (66) and the attachment (67) takes place via the work vehicle bus system (15) and the attachment bus system (27).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a work vehicle. The work vehicle is, for example, a tractor, an excavator, a wheel loader, or a similar carrier vehicle, which has a hydraulic supply with which hydraulic actuators can be supplied. The work vehicle itself can have permanently mounted hydraulic components. Furthermore, the work vehicle preferably has an interface to which various attachments can be mounted. The hydraulic supply preferably comprises a central hydraulic pump with which a volume flow of pressurized hydraulic fluid can be provided. The hydraulic supply preferably further comprises a tank into which returning hydraulic fluid from hydraulic actuators can flow and from which the central hydraulic pump pumps the hydraulic fluid again.

[0002] The invention further relates to an attachment, which may be, for example, a front loader, a wheel loader bucket, a mower, a plow, or the like. Such attachments preferably also have hydraulic functions, which are implemented with hydraulic actuators on the attachment. The hydraulic actuators on the attachment can, for example, be hydraulic actuating cylinders. In embodiments, the hydraulic actuating cylinders can be differential cylinders with opposing pressure chambers. In further embodiments, several hydraulic actuating cylinders can also be interconnected and form a (common) hydraulic actuator. In principle, various types of hydraulic actuators can be provided on the attachment.

[0003] In the following, reference is partly made to the design of the work vehicle as a tractor and the design of the attachment as a front loader that can be mounted on the tractor, whereby the same may then apply to a different design of the work vehicle and / or the attachment.

[0004] Tractors equipped with a front loader are used in agriculture or municipal applications for lifting, lowering, and transporting loads. It is also possible for a tractor with a front loader to function as a wheel loader.

[0005] Known front loaders have a rocker arm with a column that can be mounted on a mounting bracket, in particular on a tractor attachment. At the end of the rocker arm facing away from the column, the front loader has a tool holder, via which the front loader can be releasably coupled to a tool (e.g., a manure fork, a shovel, a pallet fork, a fork with heavy-duty tines, a round bale fork, or a beet basket). It is also possible for a tool that performs a working stroke (in particular, cutting pliers, a box rotator, a gripping tool, e.g., a film bale gripping tool, a solid manure gripping tool, or a log gripping tool) to be attached to the front loader.

[0006] Conventional booms consist of a front beam and a rear beam. The beams are formed from tubular steel sections that are welded together at an angle at their facing ends. A lifting cylinder, whose hydraulic pressure is provided and controlled by the work vehicle, allows the boom to pivot about a pivot bearing that can be formed between the column and the boom. A tilting cylinder, whose hydraulic pressure is also provided and controlled by the work vehicle, allows the tool holder to pivot relative to the boom. The hydraulic pressure applied to the hydraulic cylinders can be controlled by the driver using levers.Alternatively, the hydraulic actuation of the hydraulic cylinders can be controlled via a joystick or a joystick lever. Moving the joystick or joystick lever forward and backward can raise and lower the front loader's boom, while moving the joystick or joystick lever to the right and left changes the pivot angle of the tool holder relative to the boom around a transverse axis. Additional push-button and / or toggle switches can control additional functions, in particular the actuation of a tool performing a working stroke.

[0007] The hydraulic pressure on the hydraulic cylinders is provided via connecting lines between the work vehicle and the front loader, with the hydraulic fluid being supplied by a hydraulic pump on the work vehicle. The hydraulic system can be controlled from the driver's seat by the driver using controls such as levers, switches, or a joystick, and by means of control devices provided on the work vehicle and / or by means of control devices located on the front loader. The connecting lines of the hydraulic system between the work vehicle and the front loader can be individually connected via connections, or a so-called "multi-coupling" can be used, via which several or all hydraulic connections are connected simultaneously.

[0008] The tool holder can be designed as a so-called Euro quick-change frame or as a tool holder according to one of the standards EN 12525 or ISO 24410.

[0009] Automatic coupling devices are also used, which allow the tool holder to be coupled to the tool and locked without the driver having to leave the cab.

[0010] Coordination devices designed as parallel guides can be used to coordinate the hydraulic loads of the hydraulic cylinder for raising and lowering the swing arm and the hydraulic cylinder for pivoting the tool holder relative to the swing arm in such a way that the angle between the tool holder and the ground does not change or only changes within narrow limits during the lifting and lowering of the swing arm.

[0011] In this technical field, the invention relates to an attachment for a work vehicle and a vehicle combination comprising a work vehicle and an attachment mounted thereon. Furthermore, the invention relates to a computer program product. STATE OF THE ART

[0012] The applicant's patent DE 10 2005 048 280 B4 discloses prior art relating to valves of the work vehicle which can be actuated by the driver for controlling the hydraulic supply of hydraulic cylinders of the front loader, additional solenoid valves and hydraulic coupling devices for coupling connecting lines between the work vehicle and the front loader.

[0013] The applicant's published application DE 10 2005 053 041 A1 discloses prior art relating to a front loader with a column, rigidly connected beams, and an implement holder, as well as a lifting cylinder and a tilting cylinder. The front loader has a parking support that can be folded out via an additional hydraulic cylinder. When the parking support is extended, the front loader can be parked on the implement holder or a tool attached to it, such as a shovel, and the parking support. The center of gravity of the front loader with the tool is located on the ground between the parking locations. However, the front loader can also extend beyond the space between the parking locations to ensure good accessibility of the column and enable the column to be coupled to the attachment bracket of the work vehicle.

[0014] The applicant's patent DE 10 2009 046 213 B4 discloses prior art for the design of a tool holder according to ISO 24410 and with regard to a locking device for locking the tool in the tool holder.

[0015] The applicant's patent EP 1 813 730 B1 discloses prior art for the design of a hydraulic system for controlling a front loader and for pressure control in the hydraulic system.

[0016] The applicant's patent EP 1 903 147 B1 discloses the prior art for the geometric design of the beams of a front loader's swing arm and the integration of the front loader's actuating kinematics with the hydraulic cylinders into the front loader.

[0017] The applicant's patent EP 2 840 186 B1 discloses prior art for the design of an attachment bracket, here in the form of a so-called bone, and for the design of a locking or latching device for locking the column of the front loader to the attachment bracket of the tractor.

[0018] The patent EP 3 158 842 B1 discloses design options for an attachment console of the work vehicle, which here is formed by two attachment towers on both sides of the work vehicle, which have plate-shaped frame elements extending in the longitudinal direction and vertically extending brackets with a bone at the end.

[0019] The applicant's patent EP 3 431 668 B1 discloses general prior art, usable within the scope of the invention, for the design of a partial fairing of the front loader for covering moving components, in particular a control rod.

[0020] The applicant's patent application EP 4 144 925 A1 discloses further possibilities for designing an attachment bracket in the form of an attachment tower, which can be used within the scope of the invention, wherein the attachment tower is at least partially manufactured by means of solid forming. OBJECT OF THE INVENTION

[0021] The present invention is based on the object of proposing an attachment and a vehicle combination formed with a work vehicle and an attachment, which with regard to the control and / or coordination of the operation of the work vehicle and the attachment and / or to enable an extended range of functions is improved. Furthermore, the invention is based on the object of proposing a computer program product for a correspondingly improved vehicle combination. SOLUTION

[0022] The object of the invention is achieved according to the invention with the features of the independent patent claims. Further preferred embodiments of the invention can be found in the dependent patent claims. DESCRIPTION OF THE INVENTION

[0023] An attachment according to the invention, in particular a front loader, has a hydraulic system with two, three, or more hydraulic actuators. The hydraulic actuators are, in particular, a single- or double-acting lifting cylinder, via which a rocker arm of the attachment can be raised and lowered, and / or a single- or double-acting tilting cylinder, via which a tool holder can be pivoted relative to the rocker arm. Within the scope of the invention, it is entirely possible for the hydraulic system to have additional hydraulic actuators to enable an expanded range of functions. For example, the attachment or the front loader can also have a telescopic rocker arm, with the rocker arm being telescoping via another actuator configured as a hydraulic actuating cylinder (cf. the unpublished European patent application EP 23185 356).5, which is made the subject of the present disclosure with regard to the control and design of a telescopic rocker arm. The hydraulic actuator can also be an actuating cylinder, hydraulic drive, or hydraulic motor that is part of the attachment or a tool attached thereto. It is also possible for a hydraulic actuator to be an actuating cylinder of a parking support of a front loader according to DE 10 2005 053 041 A1.

[0024] The invention is based on the finding that, for conventional vehicle combinations, the interface between the work vehicle and the attachment exclusively features a hydraulic interface, via which a hydraulic control pressure for a lifting cylinder and a hydraulic control pressure for a tilting cylinder, which are controlled by a valve device of the work vehicle, are transmitted from the work vehicle to the attachment. The attachment is thus a type of "passive system" whose operating state is determined by the work vehicle without any possibility of electronic influence from the attachment.

[0025] According to the invention, it is proposed that the attachment have an attachment bus system. The attachment bus system has an attachment bus interface. The attachment bus system can be connected to a work vehicle bus system via the attachment bus interface. For this purpose, the attachment bus interface can be designed as at least one plug or a combined plug strip. It is also possible for the attachment bus interface to be designed for a suitable connection for automatically coupling the attachment to the work vehicle. It is further possible for the attachment bus interface to be integrated into an overall interface serving additional functions, into which hydraulic connections can also be integrated.

[0026] In one variant of the invention, the attachment has pressure sensors that measure pressures in the hydraulic system. For example, it is possible for pressure sensors to measure the pressure in a pressure chamber of a hydraulic actuator or preferably in both pressure chambers of the hydraulic actuator (directly or indirectly), which preferably applies to the lifting cylinder and / or the tilting cylinder. According to the invention, the pressure sensors are then coupled to the attachment bus system (directly or via a control unit of the attachment) in such a way that the measurement signals from the pressure sensors (or signals calculated therefrom by the control unit) can be transmitted via the attachment bus system. The measurement signals from the pressure sensors or the calculated signals can also be transmitted to the work vehicle bus system via the attachment bus interface and a work vehicle bus interface.

[0027] For an alternative or cumulative variant of the invention, the attachment has motion sensors. The motion sensors detect a travel or angle of the attachment, which describes an operating state of the attachment. For example, a motion sensor can detect a travel of a hydraulic actuator, in particular of the lifting cylinder and / or the tilting cylinder. It is also possible for a motion sensor to detect an angle of rotation of a joint of the attachment, for example an angle of rotation of the tool holder relative to the swing arm and / or an angle of rotation of the swing arm relative to the column. The motion sensors are then coupled (directly or via a control unit of the attachment) to the attachment bus system in such a way that the measurement signals from the motion sensors (or signals calculated therewith by the control unit) are transmitted via the attachment bus system (and possiblycan also be transmitted via the attachment bus interface, the work vehicle bus interface to the work vehicle bus system).

[0028] Within the scope of the invention, the connection between the attachment bus interface and the work vehicle bus interface can be used unidirectionally for transmitting signals between the work vehicle and the attachment, or unidirectionally for transmitting signals between the attachment and the work vehicle. Preferably, data is transmitted bidirectionally between the work vehicle and the attachment.

[0029] The measurement signals recorded by means of the pressure sensors and / or motion sensors can be made available (directly or by conversion by a control unit of the attachment) within the scope of the invention for a control unit of the work vehicle and used there for the appropriate adjustment of the operating state of the work vehicle and the units of the work vehicle according to an operating state of the attachment and / or displayed for a user on a display device in the driver's cab.

[0030] According to a further proposal of the invention, the attachment has an electronically controlled valve device. The attachment further has at least one hydraulic supply connection. The hydraulic supply connection is then connected to a supply line of the work vehicle for the purpose of providing the pressurized hydraulic fluid. The supply line is supplied with the hydraulic fluid by a pump of the work vehicle.

[0031] Preferably, the attachment has at least one hydraulic supply connection that can be connected to the work vehicle, while there are no hydraulic control connections between the work vehicle and the attachment. Rather, in this case, the control signals are transmitted exclusively electrically or electronically, preferably via the attachment bus interface. A supply connection or supply line can be a connection or line through which hydraulic fluid is transferred from the work vehicle to the attachment, or a connection or line through which hydraulic fluid is returned from the attachment to the work vehicle.

[0032] Within the scope of the invention, the operation of the pump of the work vehicle can also be controlled as needed by means of the measurement signals of the pressure sensors and / or motion sensors transmitted to the work vehicle or the signals calculated therewith and / or valve elements in the area of ​​the hydraulic supply system of the work vehicle can be controlled depending on these measurement signals.

[0033] For the embodiment according to the invention, the valve device is responsible for controlling or regulating the hydraulic loading of the hydraulic actuators depending on information provided via the attachment data bus.

[0034] This will be explained using a simple example that does not limit the invention: If the driver in a cab of the work vehicle gives a manual signal to raise or lower the attachment (for example, using a joystick), such a signal can be transmitted via the work vehicle bus system, the work vehicle bus interface, and the attachment bus interface to the attachment bus system, and the valve device is then controlled according to this signal. In this case, the control pressures are not generated on the work vehicle, but directly on the attachment. It is even possible that, based on the measurement signals from the pressure sensors and / or motion sensors, not only the hydraulic control pressures are controlled, but the hydraulic pressure on the hydraulic actuators is also regulated by feedback of the actual signals.

[0035] For a special embodiment of the attachment according to the invention, it has a stroke sensor that detects the stroke of a lifting cylinder of the attachment. The stroke sensor can be located outside the lifting cylinder and detects the relative position between components moving when the swing arm is raised and lowered. It is also possible for the stroke sensor to be integrated into the lifting cylinder itself and, for example, detect a relative movement of the piston of the lifting cylinder relative to the cylinder housing of the lifting cylinder.

[0036] Alternatively or cumulatively, it is possible for the attachment to have a tipping path sensor that detects the tipping path of a tipping cylinder of the attachment.

[0037] With regard to the integration of the tipping travel sensor into the attachment, the above statements regarding the lifting travel sensor apply accordingly.

[0038] Alternatively or cumulatively, it is possible for the attachment to have a pressure sensor that detects a pressure applied to a pressure chamber of a lifting cylinder or a tilting cylinder or another hydraulic actuator. Preferably, however, the attachment has a pair of pressure sensors that detect the pressures applied to oppositely acting pressure chambers of a double-acting lifting cylinder or tilting cylinder or any other actuating cylinder. Within the scope of the invention, the attachment can also have an angle sensor that detects a pivot angle of the swing arm of the attachment relative to the column of the attachment, and / or an angle sensor that detects a pivot angle of a tool holder of the attachment relative to the swing arm of the attachment.Within the scope of the invention, the signals of the said sensors are then transmitted (directly or after conversion by a control unit of the attachment) via the attachment bus system.

[0039] According to a further proposal of the invention, the attachment bus system also has a tool bus interface. The attachment bus system can be connected to a tool bus system via the tool bus interface. In this way, an overall bus system can be created via which the work vehicle bus system, the attachment bus system and the tool bus system can communicate with one another (unidirectionally or bidirectionally). This embodiment is particularly advantageous if the tool has a hydraulic actuator. In this case, a sensor of the tool, in particular a motion sensor or a pressure sensor, can detect an operating position of the tool and this operating state can then be transmitted to the attachment bus system and / or the work vehicle bus system via the measurement signal (directly or with conversion by a control unit of the front loader). In the work vehicle, for example,The operating position of the tool can be displayed to the user on a display, or the operating position can be used to control additional actuators or units of the work vehicle or attachment. It is also possible, however, for control signals to be transmitted from the work vehicle via the attachment or from the attachment to the tool bus system, which are then used by a control unit of the tool to control or regulate the operating position of the tool's actuator.

[0040] It is possible for the attachment to only have the attachment bus system, which can then be directly coupled to any sensors and / or to any control unit for the valve device or units. According to one proposal of the invention, in addition to the attachment bus system, which, as explained, is coupled to the work vehicle bus system and / or the tool bus system, the attachment has a further attachment bus system, which preferably does not communicate directly with the work vehicle and the tool. A control unit is then arranged between the attachment bus system and the further attachment bus system, via which control unit the two aforementioned bus systems are connected to one another. For example, it is possible for the attachment bus system to be designed as an ISOBUS, while the further attachment bus system is designed as a CAN bus system.The additional attachment bus system then serves to connect the sensors and / or the valve device and any units. According to this embodiment, the two different bus systems can be specifically adapted to the respective requirements. For example, the additional attachment bus system can enable faster data transmission and thus faster control of the valve device and actuators, which can be ensured on the one hand by a faster data transmission rate of the additional attachment bus system and / or by a reduction in the volume of data exchanged via this additional attachment bus system. To name just one example that does not limit the invention, image signals can also be transmitted via the attachment bus system, whereas this is not the case for the additional attachment bus system.

[0041] A further solution to the problem underlying the invention is a vehicle combination comprising a work vehicle, in particular a tractor, and an attachment mounted on the work vehicle, in particular a front loader. The work vehicle then comprises a work vehicle bus system. The work vehicle bus system comprises an operating device, which may, for example, be a joystick or a touchscreen. Furthermore, the work vehicle bus system may comprise a display device, such as a monitor, which, if configured as a touchscreen, may also simultaneously provide an operating unit.

[0042] In this case, the work vehicle bus system has the previously mentioned work vehicle bus interface. The attachment of the vehicle combination can then be designed as described above. The work vehicle bus system and the attachment bus system are then linked to each other via a connection between the work vehicle bus interface and the attachment bus interface. It is also possible for the vehicle combination to additionally have the tool with a tool bus system, in which case the attachment bus system is additionally linked to the tool bus system via suitable interfaces.

[0043] The interfaces can also be connected to the electrical power supply. For example, an interface for a power supply can be provided in the form of a three-pin socket.

[0044] The implement bus interface and the work vehicle bus interface can be designed, for example, as ISOBUS sockets. As a non-limiting example, the ISOBUS socket can be designed as a four-pin Deutsch connector.

[0045] Finally, it is also possible for coupling to take place via hydraulic connections, in particular for a hydraulic supply.

[0046] In a particular embodiment of the invention, the work vehicle has an ISOBUS socket at the rear, which is intended for connection to a rear-mounted implement, which may be driven by a PTO. In this case, a cable connection of the work vehicle bus system, designed as an ISOBUS, can run from the rear to the front of the work vehicle, where the connection to the implement bus system, also designed as an ISOBUS, is established via suitable interfaces.For this embodiment, a branching plug or branching point can be inserted into the ISOBUS socket already present in the rear area, which enables a branching into an ISOBUS line that is connected to the attachment in the rear area, as well as an ISOBUS line that runs along the work vehicle from the rear area to the front area and enables coupling with the work vehicle bus system in the front area. It is possible, for example, for the latter ISOBUS line to be routed underneath the work vehicle in the longitudinal direction of the work vehicle from the rear area to the front area. In this case, the ISOBUS line can be integrated into a connecting or cable harness with additional lines, cables, hydraulic lines, etc.

[0047] According to one embodiment of the invention, the work vehicle and / or the attachment have / have a control unit with control logic. This control unit with the control logic then coordinates the operation of the work vehicle and the operation of the attachment via the attachment bus interface. If a control unit or control logic is mentioned below, this can refer to the case where the control unit with the control logic (and an associated valve device for controlling the control pressures for the lifting cylinder and / or the tilting cylinder and any other actuators) can be arranged in the area of ​​the work vehicle and / or in the area of ​​the attachment, without this being emphasized again in each case.

[0048] However, it is also possible for a control unit with control logic to be arranged on the work vehicle and the attachment, whereby the control units and control logic can then communicate with each other to ensure the functionalities explained below.

[0049] According to the invention, the following extended functional scopes can preferably be provided on an attachment and / or a vehicle combination: a) It is possible for pressure control to take place on the basis of the measurement signals for the pressures in the lifting cylinder and / or tilting cylinder and / or any other hydraulic actuator of the attachment or tool, so that the operating positions of the valve device for generating the control pressures for the lifting cylinder, tilting cylinder or any other hydraulic actuator can be controlled by means of the control logic and control unit, thereby achieving increased precision. It is also possible for the pressure control to include pressure limitation so that excessive pressures, which could lead to damage, can be reliably avoided. The following are some possible examples of pressure control that do not limit the invention: It is possible, for example, for a tool to be designed as a bale gripper that is hydraulically actuated by an actuating cylinder or motor of the tool.For comfortable and safe use, the clamping force of the bale gripper must be limited; this can be achieved based on pressure control. If different tools with hydraulic actuators that require different maximum operating pressures are held on the attachment, the control logic can set a tool-specific pressure limit based on manually entered or automatically recorded information about which tool is currently coupled to the attachment. It is also possible to ensure a pressure relief function, which is particularly the case when a hydraulic motor is operated on a tool. Pressure relief can then prevent overloading of the motor and tool, which can occur, for example, due to jamming or other blockage of the hydraulic motor.If the pressure exceeds a previously defined threshold, the valve device is controlled in such a way that no further increase in pressure occurs or the pressure is reduced. At the same time, information can be transmitted via the bus system to the work vehicle and the user via a monitor or other display device that an overload or improper operation, in particular a blockage of the hydraulic motor, has occurred. b) A further function possible within the scope of the invention is that a load carried by the attachment is automatically determined by means of the control logic. Alternatively or cumulatively, a coordinate of a center of gravity of a load carried by the attachment can be determined.For example, the load is the mass of the tool held on the attachment and / or the mass of an object or material supported on the tool, in particular a material in a bucket or an object on a pallet. Within the scope of the invention, the load and / or the center of gravity can be determined based on the measurement signals from the pressure sensors. The actuating force of a lifting cylinder or tilting cylinder can be calculated from the resulting force hydraulically exerted on the piston of the cylinder, which in turn depends on the pressures in the two pressure chambers of the actuating cylinder. If the resulting force in a lifting cylinder is known (for static operation or dynamic operation), for example, the control logic converts this resulting force into the load using the specific kinematics of the attachment and / or the tool.The specific kinematics of the attachment must be taken into account because, for example, the same load on a bucket attached to a front loader will result in different required resulting forces in the area of ​​the lifting cylinder for different boom lengths. On the other hand, the signals from the motion sensors are also taken into account when determining the load because, for example, the support force of the lifting cylinder for holding a load at a given height can depend on the operating position of the attachment, such as the pivot angle of the boom relative to the column. The same applies to determining the coordinates of the load's center of gravity. If the control logic is to determine both the load and the coordinates of the center of gravity, two unknown quantities must be determined from a mathematical perspective.Determining the two unknowns requires that sufficient measurement signals are available, namely the pressure signals from the pressure sensors on the one hand and the motion sensors on the other. Within the scope of the invention, after determining the load and / or the coordinates of the center of gravity of the load, these can be taken into account for controlling the operating positions of the attachment or the vehicle combination. For example, the load and the coordinates of the center of gravity can be used to determine when a critical operating state of the vehicle combination is reached, which can result in reduced stability with the risk of tipping over. Based on a determined load and / or the center of gravity, the operating speeds of the actuating cylinders can also be limited and / or the actuating travel of the actuating cylinders can be limited.Preferably, the control logic stores the type of attachment, including its kinematics and dimensions or related characteristic parameters, on the one hand, and the kinematic parameters or characteristic parameters of the tool, on the other. This allows for a one-time calibration of an attachment and / or tool by determining the respective parameters during test operation, in particular the load and at least one coordinate of the center of gravity, with subsequent storage of this data. If a specific tool and / or attachment is then used in the vehicle combination, this is automatically detected or manually selected by the user, and the determined parameters are then read out and used for subsequent operation with the attachment or tool.Preferably, the load and / or the coordinate of a center of gravity is determined within a predetermined partial actuating range of the actuating range of the lifting cylinder and / or tilting cylinder. It is also possible that (in particular for determining the coordinate of a center of gravity) two different partial actuating ranges or specific different actuating positions of at least one actuating cylinder, in particular the lifting cylinder, are approached. It is possible that the result of the determination of the load and / or a coordinate of the center of gravity is displayed on a display device of the work vehicle. If multiple weighing processes take place, the control logic can be suitably configured to then add up the multiple determined loads to obtain a total weight. Preferably, a load and / or a coordinate of a center of gravity is determined while the vehicle combination is parked.However, it is also possible within the scope of the invention for the load and / or the coordinates of the center of gravity to be determined while the vehicle combination is traveling, which is preferably only the case below a threshold travel speed. c) A further proposal of the invention is based on the knowledge that for an attachment, the force ratios on a lifting cylinder depend on the size of the load. If the lifting cylinder is controlled by providing a control pressure, different loads carried by the attachment lead to different lifting speeds of the lifting cylinder for the same control pressure, whereby a lifting speed can be either a positive speed, which can lead to an increase in height or a lifting, or a negative lifting speed, which reduces the height and thus lowers the load.Preferably, the lowering of the boom is controlled or regulated in such a way that, when the same lowering command is given by the driver or by a control unit, e.g., when a joystick controlling the lowering is deflected the same way, the same lowering speed of the boom around the joint is achieved, regardless of the load, or the same lowering speed of the tool is achieved in the vertical direction. Known designs of attachments or front loaders, for example, can result in lowering occurring at excessive speed when a heavy load is carried and the driver commands lowering the lifting cylinder. In the worst case, this makes sensitive control by the user impossible and can lead to damage.According to the invention, the lifting speed of the lifting cylinder and / or the tipping speed of the tipping cylinder can be controlled or regulated depending on the load, taking into account the measurement signals from the pressure sensors and / or the measurement signals from the motion sensors. Such control or regulation can consist of specifying the hydraulic control pressures acting on the lifting cylinder and its pressure chambers. It is also possible to arrange an adjustable throttle in a pressure chamber that must be emptied to lower the lifting cylinder, the throttle position of which then depends on the load.It is also possible within the scope of the invention for the control or regulation of the lifting speed and / or tilting speed to take into account the position of an operating element, in particular a joystick, so that a greater lifting speed or tilting speed is controlled for a stronger actuation or deflection of the operating element or joystick than for a smaller actuation or deflection. For one proposal of the invention, the control logic ensures that the lifting speed is the same in both directions, so that the same actuation of the operating element or deflection of the joystick in different directions for lifting and lowering results in the same actuating speed of the lifting cylinder in both directions.However, it is also possible that the controlled or regulated speed is not the speed of the actuating cylinder, but a speed of the attachment or tool at a significant position, which may require that different actuating speeds of the actuating cylinders must be achieved depending on the operating position of the attachment and / or tool and thus depending on the current kinematic conditions. d) It is possible within the scope of the invention that when a specific operating state of the attachment and / or tool is brought about, the specific operating state is stored, in particular by storing the pressures to which the pressure chambers of the lifting cylinder and the tilting cylinder and any other actuator are subjected and / or the measurement signals of the motion sensors in the specific operating state.If such an operating state is to be restored at a later date, this can be done automatically by the control logic automatically applying pressure to the hydraulic actuators to restore this stored operating state. This automatic restoration of the stored operating state can be triggered manually by the driver, for example, via a button, touchscreen, or joystick, or it can be triggered automatically depending on any operating state of the vehicle combination, the detection of a specific geodetic position of the vehicle combination via a GPS system, or the reaching of a positioning range.Preferably, storage and / or retrieval is possible in two different modes: For one mode, only the storage and retrieval of an operating position of an actuating cylinder, in particular of the lifting cylinder or tilting cylinder, takes place. In contrast, for another operating mode, the combined storage and retrieval of both an operating position of the lifting cylinder and an operating position of the tilting cylinder can take place. Alternatively or cumulatively to the storage of only specific operating positions, a storage and retrieval of an operating state history can also take place. To name merely one example that does not limit the invention, such a stored operating state history can include an initial position in which a front loader is lowered and a bucket attached to the front loader rests flat on the ground.In this starting position, the bucket can be filled into a pile of material by moving the vehicle combination forward. The bucket is then raised by operating the lifting cylinder, while the bucket is tilted backward by operating the tilting cylinder to secure the contents in the bucket during the lifting movement and any subsequent travel movement. An end position is reached when the boom with the tool is at a predetermined working height. The stored operating status history therefore contains the operating variables and profiles between the starting position and the end position. If the same operating status history is required at a later time, the driver does not have to bring about this operating status history by specifically controlling the lifting cylinder and the tilting cylinder.Instead, the operating state history can be automatically restored by the control logic. The restoration of the operating state history can be triggered by pressing a button or by a specific movement of the joystick. Different modes are also possible in this case. In one mode, only an operating state history can be induced for the lifting cylinder and / or the tilting cylinder, while in another mode, the operating state histories of both the lifting cylinder and the tilting cylinder are restored simultaneously. e) It is possible for the control logic to initiate an automatic oscillating movement of a tool holder of the attachment.This is advantageous, for example, when a bucket on a front loader is not automatically completely emptied when tipping, but rather material still clings to the inner surfaces of the bucket, which then needs to be "shaken off" as a result of the oscillating movement. It is possible, for example, for such an automatic oscillating movement to be triggered by a switch, joystick, or similar device, whereby the control logic then hydraulically loads the tilt cylinder to produce an oscillating tilting movement. The amplitude of the oscillation can be specified by a switch or the extent to which a joystick is operated. It is possible for the amplitude of the oscillation to remain constant for a predetermined period of time or for the duration of an actuation of an actuating element. It is also possible for the amplitude of the oscillating movement to decay and decrease over time.Within the scope of the invention, there are a variety of possibilities for inducing the oscillating movement of the tool holder. For example, it is possible for the valve device to apply greater and lesser pressures to the pressure chambers of the tilting cylinder alternately and in opposite directions. Such varied hydraulic loading of the pressure chambers by means of the valve device can be achieved by alternating connection to a pressure source and a pressure sink. It is also possible for the hydraulic system to be completely shut off, but for a limiter of the hydraulic system or a piston to be moved back and forth in an oscillating manner by means of an electric drive.It is also possible for the hydraulic system connected to the tipping cylinder to be connected to a hydraulic oscillator that induces hydraulic oscillations, whereby an initial deflection of the oscillator can be brought about by a pressure jump when a pressure chamber of the tipping cylinder is pressurized. It is possible for the oscillating movement of the tool holder to be brought about exclusively by the tipping cylinder. It is also possible for the movement to be additionally supported by an oscillating movement of the lifting cylinder. It is also possible, alternatively or cumulatively, for the engine of the work vehicle to be driven in such a way that the work vehicle (and thus the front loader with the tool holder) executes an oscillating forward-backward movement.An oscillating movement of the tool holder can also be used, for example, to shake material arranged in a bucket in such a way that it is compacted. It is possible for the frequency of the oscillating movement to be specified by the driver, or for different specific frequencies to be preset. It is also possible for the frequency of the oscillating movement to be dependent on the load. f) The control logic can ensure automatic vibration damping of the attachment. Vibrations of the attachment can occur, for example, if the actuation of the actuating cylinders changes, for example, if a actuating cylinder is actuated quickly or braked quickly.In this case, resulting dynamic oscillations of the attachment can be dampened, for example by increasing the throttling effect of throttles in the supply lines to the pressure chambers of the actuating cylinders or by actively counteracting this by pressurising pressure chambers in such a way that resulting oscillations are reduced. g) It can be problematic if several actuating cylinders on the attachment, in particular the lifting cylinder, the tilting cylinder and at least one other hydraulic actuator of the attachment and / or tool, have to be operated in parallel. In this case, priority may be given to the hydraulic fluid being supplied to the consumer in the area where the pressure is lowest, which can then result in an undersupply of the other consumers, which can lead to the other consumers not being operated or not being operated sufficiently.According to one embodiment of the invention, the control logic automatically controls and / or regulates the distribution of a supply flow of hydraulic fluid, which is transmitted from the work vehicle to the attachment, to the consumers, in particular the lifting cylinder, the tilting cylinder and / or at least one further hydraulic actuator, by suitably controlling the valve device. On the one hand, the distribution can be carried out in such a way that, despite different pressures of the individual consumers, the consumers are operated to the required extent. It is also possible, however, for the control logic to distribute the supply flow based on prioritization in such a way that the entire supply flow or a minimum portion of the supply flow is made available to a higher-priority consumer (at least for a period of time).Within the scope of the invention, the control logic can also influence the operation of the pump of the work vehicle to control the supply, in particular by controlling the speed of the pump and / or a stroke of the pump. h) Within the scope of the invention, the control logic can also ensure parallel guidance of a tool holder. This embodiment is based on the fact that for specific operating processes, for example lifting a pallet on a tool designed as a pallet fork, it is important that the orientation of the tool relative to the ground does not change during lifting or lowering. However, the pivoting of the rocker arm by actuating the lifting cylinder for lifting and lowering leads to a change in the angle of the tool holder relative to the ground due to the circular movement of the rocker arm around its linkage.In this case, the control logic can also control the tilting cylinder in parallel with the actuation of the lifting cylinder in such a way that the pivoting of the tool holder resulting from the actuation of the lifting cylinder is counteracted by the actuation of the tilting cylinder in such a way that the orientation of the tool does not change. For this purpose, the control logic can take into account a previously taught-in, read-in or user-selected type of attachment and / or type of tool to determine the automatic actuation of the lifting cylinder and the tilting cylinder to ensure parallel guidance of the tool holder. i) It is possible for the control logic to limit the travel of the lifting cylinder, the tilting cylinder and / or any other actuating cylinder by specifying a minimum and / or maximum travel of the actuating cylinder.It is possible that this limitation can be used to specify a kind of "working window" for the actuating cylinder and thus for the attachment or tool. To cite merely one non-limiting example, an upper limit for the travel of the lifting cylinder can be set such that the vehicle combination can be operated in a building with a reduced ceiling height. The maximum limit for the travel of the lifting cylinder is then selected such that a collision of the attachment and the tool held on it with the building's ceiling is excluded. j) It can be problematic if the travel of an actuating cylinder is limited by a stop. If the actuating cylinder and thus the attachment reach the stop, the resulting stop forces and the oscillations triggered by the stop can impair comfort, impair the load held on the attachment, and cause damage.According to one embodiment of the invention, the control logic ensures damping in the region of an end position of a travel of the lifting cylinder and / or an travel of the tilting cylinder in order to at least reduce such impairments. This damping can, for example, consist in the motion sensors detecting when the actuating cylinder is at a predetermined distance from the end position. If this is the case and the actuating cylinder continues to approach the end position, the control logic can actuate the valve device in such a way that a lower actuating speed is achieved, which can then lead to reduced impact forces. It is also possible for the speed to be successively reduced (in steps or continuously) as the end position is approached.In a particular embodiment of the invention, damping takes into account the kinetic energy of the attachment and, under certain circumstances, also the load held on the attachment, such that damping is increased at greater kinetic energy. In addition to influencing the hydraulic pressures applied to the pressure chambers of the actuating cylinders, damping can also be achieved by means of an adjustable throttle, whereby the damping set by the control logic can then increase as the end position is approached or can be dependent on the calculated kinetic energy of the attachment, possibly including the tool and the load held on it. It is also possible for the distance from the end position of the travel path for which an increase in damping occurs to be dependent on a calculated kinetic energy of the attachment, possibly including the tool and the load held on it.k) A further aspect of the invention is devoted to operation of the vehicle combination in which the attachment with the tool attached to it and possibly a carried load is moved over an uneven road surface. If in this case the operating position of the attachment and the tool remains unchanged, the attachment, the tool and the load follow the unevenness of the road surface, which can result in considerable dynamic forces. The invention proposes that the control logic controls and regulates a reduction in the movements of the tool holder when driving on uneven road surfaces. In this case, damping of occurring vibrations can be brought about by suitable control of the pressure chambers of the actuating cylinders and / or increasing the damping for the pressurization of the pressure chambers by means of an adjustable throttle device.It is also possible for the actuating cylinders to be controlled in such a way that, regardless of unevenness in the road surface, the control or regulation objective is that the tool holder always has the same absolute height and / or always has the same orientation. In this case, the valve device for controlling the control pressures of the lifting cylinder and the tilting cylinder is controlled taking into account a height sensor, the motion sensors and / or the measurement signals from the pressure sensors. Alternatively or cumulatively, within the scope of the invention, the control logic can also control a level control device of the work vehicle in such a way that movement of the chassis of the work vehicle is at least reduced when driving on uneven road surfaces, which can then also reduce oscillations of the column and thus of the attachment and tool held on the column.In this case, for example, the chassis of the work vehicle can have air suspension or the chassis of the work vehicle can be supported on the vehicle wheels via adjustable springs and / or dampers. According to one proposal of the invention, the damping of movements of the tool holder is achieved by at least one pressure chamber of an actuating cylinder being connected via a valve to a hydraulic accumulator, in which a hydraulic volume is preferably supported on a pneumatic volume via a movable wall or diaphragm. If damping is to be achieved, the connection between the pressure chamber and the accumulator can be specifically established via the valve. It is also possible for the valve to have different operating positions in which the connection is made via different throttle cross-sections (in steps or continuously), so that the extent of the damping can be influenced via the operating position of this valve.l) According to a further proposal of the invention, the control logic is suitably designed to ensure locking and / or unlocking of a locking device that locks the tool to the tool holder of the attachment. According to the invention, this control logic is for the first time arranged with a valve device for actuating the locking device between the locked position and the unlocked position on the attachment itself. According to a special proposal of the invention, locking and / or unlocking of the locking device is only possible in selected operating positions or operating position ranges, for which purpose the control logic can use the measurement signals from the motion sensors. For example, unlocking of the tool can only be enabled by means of the control logic when the attachment is lowered.m) Within the scope of the invention, the multifunctional communication between the work vehicle and the attachment can also be used to activate and / or deactivate a drive, in particular an all-wheel drive, of the work vehicle depending on an operating state of the attachment. For example, the all-wheel drive of the work vehicle can be activated depending on a lifting height of the swing arm of the attachment in order to increase the stability of the work vehicle on the ground at a specific lifting height. It is also possible for the all-wheel drive to be activated only when the lifting height of the swing arm falls below a threshold value, which makes it possible for a shovel held on the swing arm to be driven into a pile of material on the ground in all-wheel drive operation.Above the lifting height specified by the threshold value, the work vehicle can then move without all-wheel drive, which can reduce wear on the vehicle's wheels, reduce the load and tension on the work vehicle, increase steering flexibility and, under certain circumstances, also result in a smaller steering radius. n) If the load is known as a result of the previously explained automatic determination of a load carried by the attachment or through manual input of a load by the user, the control logic can also specify a maximum travel speed for the work vehicle which is dependent on the load. This contributes to the operational safety of the work vehicle during travel. o) It is also possible for the control logic to bring about a predetermined dependency of the angle of the tool holder on the travel of the actuating cylinders.This predetermined dependency can, for example, involve guidance such that the lifting cylinder and the tilting cylinder are controlled in such a way that the angle of the tool holder follows a predetermined course when lifting or lowering. For example, the course can be such that, regardless of the actuation of the actuating cylinders, the tool holder always has the same angle to the ground, which can ensure, for example, parallel guidance. However, it is also possible for the tool, in particular a shovel, to tilt automatically when lifting and lowering. p) It is also possible for a so-called speed scaling function to be provided by means of the control logic.This means that, using the control unit, the control logic, and the valve device of the attachment, different conversion characteristics can be used to convert a signal specified by the driver, for example, via the joystick and transmitted via the attachment bus interface, into a control of the lifting cylinder and / or the tilting cylinder. The different conversion characteristics can then be selected automatically by the control unit depending on the operating situation, or the driver can select one conversion characteristic from several available conversion characteristics.For example, it is possible for a first conversion characteristic to relate a joystick deflection to the control signal for the valve device, or to an opening position of a valve, or to a pressure adjustment by the valve device, while a second conversion characteristic may relate to a different linear dependency with a different gain factor or even a non-linear dependency. Any curved dependency, with or without a jump and / or kink, can be used as a non-linear dependency. To name just one example that does not limit the invention, a small gain factor may be used for a small joystick deflection, while a larger gain factor may be used for a larger joystick deflection.This can be used to advantage by allowing the driver to make sensitive control decisions for small joystick movements, while for larger movements the cylinder and / or tilt cylinder can be controlled at a higher speed to enable rough but fast control. q) It is possible for the control logic to ensure a so-called speed mode in which the valves and the lifting cylinder and / or tilt cylinder are controlled to achieve increased or maximum speeds. This can also include increasing or maximizing the gain of a control signal given via a joystick. r) For one suggestion, the control logic ensures a so-called float function.With a float function, opposing pressure chambers of the actuating cylinder, in particular of the lifting cylinder and / or the tilting cylinder, are short-circuited via the valve device of the attachment or connected to one another via a throttle of the valve device of the attachment. This means that the actuating cylinder can be adjusted when external forces are exerted on the attachment. For example, if a bucket attached to the tool holder of a front loader rests on the ground, the float function enables the bucket to perform a compensating movement when the ground is uneven and the vehicle is in operation. This can at least reduce damage to the ground or the forces acting on the tool and the front loader.s) Through the interaction and signal exchange between the work vehicle and the attachment via the bus system and the bus interfaces, the operation of the work vehicle's pump for providing the hydraulic pressure can be coordinated with the respective operating state of the attachment. In particular, it is possible for the work vehicle's pump to be controlled depending on a load carried by the attachment. For example, if the control unit of the attachment detects that the attachment is carrying a heavy load (in particular a load that is greater than a predetermined threshold), the pump can be controlled in such a way that an increased volume flow of hydraulic fluid is made available by increasing the stroke.It is also possible, however, that in this case the speed of the pump of the work vehicle is increased, which in one embodiment of the invention can also be brought about by increasing the speed of an engine of the work vehicle that drives the pump, or by adjusting a gearbox via which the engine of the work vehicle is coupled to the pump. It is also possible for a stroke of the pump to be reduced in order to be able to provide higher pressures, which can then be supplied to the actuating cylinders in order to enable the actuating movements despite the increased load. It is also possible for the control of the pump to be continuously changed depending on the size of the load.

[0050] Preferably, the attachment or vehicle combination has a database. Specific characteristics of tools that can be coupled to a tool holder of the attachment can be stored in the database. This characteristic data can be provided and stored at the factory or loaded and saved via a data network or a cloud connection. It is also possible for the user to teach the tool this characteristic data during initial use of the attachment by moving the attachment into specific, predefined operating positions or by running a test program, which then enables the characteristic data to be determined automatically. If a specific tool is then actually used in conjunction with the attachment, the driver can select the specific characteristic data of this tool or these characteristic data are selected automatically.Alternatively or cumulatively, specific characteristics of the attachment can also be stored in the database and retrieved for the respective attachment used, whereby the above-mentioned provisions for the characteristics of the tools apply accordingly to the provision, teaching and retrieval of the characteristics.

[0051] For automatic identification of a specific attachment and / or a specific tool to be used, the attachment or tool can have an RFID chip that contains an identifier for the respective type of attachment or tool and can be read to identify the type. It is also possible, for example, to use another identifier, particularly in the form of a readable barcode or QR code, or for the tool or attachment to be identified based on automatic image recognition of an image captured by a camera. It is also possible for the attachment or tool to have a specific contact contour that can then be scanned to identify the type of attachment or tool.

[0052] According to a further proposal of the invention, the attachment receives (at least) one control variable via the attachment bus interface. This control variable can be specified by the driver via an operating device or a joystick in the driver's cab of the work vehicle. Alternatively or additionally, this control variable can be specified automatically by a control unit of the work vehicle depending on the operating state of the work vehicle. The control variable can be, for example, a target travel of an actuating cylinder, in particular the lifting cylinder and / or the tilting cylinder or another hydraulic actuator (in particular the tool). This control variable is preferably independent of which specific attachment and / or which specific tool is attached to the work vehicle.For this proposed invention, the control unit of the attachment then has control logic that adapts the control of the valve device to the specific attachment and / or the specific tool. The control logic controls the valve device to generate the hydraulic actuation of the lifting cylinder, the tilting cylinder, and / or the actuator, on the one hand, taking into account the control variable received via the attachment bus interface. In addition, the control logic takes into account specific characteristics of the tool that is currently coupled to the attachment. This can include, for example, geometric data of the tool, characteristic data of a motor of the tool or actuating cylinder of the tool, dimensions, and coordinates of articulation points.Alternatively or additionally, the control logic can also consider specific characteristics of the attachment's geometry, such as dimensions, in particular the length of a swing arm, the height or offset of a swing arm, pivot points of the column and the attachment bracket, pivot points of the actuating cylinders, pivot points of the tool holder, and the like. Alternatively or additionally, it is possible for the control logic to additionally consider specific characteristics of the lifting cylinder, tilting cylinder, and / or other hydraulic actuator. For example, different actuating cylinders can be installed for different types of attachments, which provide the same travel for different volume flows and / or pressures in the pressure chambers.This inventive design thus enables the work vehicle to transmit control signals that are independent of the specific attachment and / or tool used, while the specific adaptation to the attachment and tool is then carried out by the control logic of the attachment's control unit. It is possible for the aforementioned characteristic data to be stored in the attachment's database, as previously explained.

[0053] According to a further proposal of the invention, the attachment has an interface via which operating data of the attachment can be transmitted. The interface can be a wired or wireless interface, whereby a wireless interface can be designed as a WLAN interface, Bluetooth interface, or similar. The operating data can be transmitted via the interface to a central computer of the user, the operator of a fleet of the work vehicle, a company in whose area the work is being carried out, or to a data cloud. To name just one example that does not limit the invention, a load automatically determined by the attachment can be transmitted via the interface. As a result of this transmission, the mass of the transported load can be documented, and the mass can then be saved for documentation purposes.

[0054] A further solution to the problem underlying the invention is provided by a computer program product. The computer program product is suitably configured for operation on a control unit of the work vehicle or the attachment. The work vehicle is configured for the attachment of an attachment, as previously explained. The computer program product has control logic that enables an operator to control the attachment using an operating device of the work vehicle via control commands, and the control commands for controlling hydraulic actuators of the attachment are transmitted to an attachment bus system via a work vehicle bus system, a work vehicle bus interface, or an attachment bus interface.

[0055] Preferably, the computer program product has control logic that enables functions, operating states or measurement signals from pressure sensors or motion sensors of the attachment or a tool held thereon to be displayed to an operator on a display device of the work vehicle.

[0056] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0057] The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be effective alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0058] With regard to the disclosure content – ​​not the scope of protection – of the original application documents and the patent, the following applies: Further features can be found in the drawings – in particular the illustrated geometries and the relative dimensions of several components to one another, as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or features of different patent claims is also possible, deviating from the chosen references of the patent claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features of different patent claims.Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

[0059] The number of features mentioned in the claims and the description is to be understood as meaning that exactly this number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least." Thus, for example, if reference is made to one element, this is to be understood as meaning that exactly one element, two elements, or more elements are present. The features mentioned in the claims may be supplemented by further features or may be the only features present in the subject matter of the respective claim.

[0060] The reference signs contained in the patent claims do not represent a limitation of the scope of the subject-matter protected by the patent claims. They serve solely to make the patent claims easier to understand. BRIEF DESCRIPTION OF THE CHARACTERS

[0061] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. 1 shows a highly schematic vehicle combination with a work vehicle, a rear attachment, a front attachment and a tool. Fig. 2 shows a spatial view of a detail of an attachment designed as a front loader. FIGURE DESCRIPTION

[0062] Fig. 1a vehicle combination 1. The vehicle combination 1 comprises a work vehicle 66. In the following, reference is made to the design of the work vehicle 66 as a tractor 2, without any restriction in this regard.

[0063] An attachment 3 is detachably attached to the rear of the tractor 2.

[0064] An attachment 67 is detachably attached to the front of the tractor 2 in the area of ​​a mounting bracket. In the following, reference is made to the design of the attachment 67 as a front loader 4, the column of which is attached to the mounting bracket, without any restriction in this regard.

[0065] The front loader 4 carries a tool 5 in the end region facing away from the tractor 2 in the area of ​​a tool holder which is detachable and locked via a locking device.

[0066] The tractor 2 has a control unit 6, which can be configured as a central control unit or comprise several interconnected sub-control units. The control unit 6 serves to control the functions of the tractor 2 and, for this purpose, controls the units of the tractor 2.

[0067] The tractor 2 has a display device 7, in particular a screen 8, and an operating device 9, in particular a joystick 10, pedals, switches, controllers, etc. The display device 7 and the operating device 9 communicate with the control unit 6, wherein operating signals input via the operating device 9 are transmitted to the control unit 6 and the control unit 6 sends information to the display device 7, which is displayed on the display device 7 in order to bring this information to the attention of the driver of the tractor 2.

[0068] The control unit 6 controls units, in particular an engine 11 and a transmission 12 of the tractor 2, in accordance with the inputs of the operating device 9 and automatically determined control commands.

[0069] The tractor 2 has a hydraulic system 13. In the hydraulic system 13, a volume flow of a pressurized hydraulic medium is provided by a hydraulic pump 14. The operation of the pump 14 is controlled or regulated by the control unit 6, wherein the control unit 6 can activate and deactivate the pump 14, specify the speed of the pump 14, and / or specify any adjustable stroke of the pump 14.

[0070] The tractor 2 has a work vehicle bus system 15, which is preferably designed as an ISOBUS 16. The control unit 6, the display device 7, the operating device 9, the engine 11, the transmission 12, and the pump 14 (as well as other components of the tractor 2) are connected to the work vehicle bus system 15, and these communicate via the work vehicle bus system 15.

[0071] The attachment 3 has a control unit 17. The control unit 17 controls the function of a hydraulic unit 18 of the attachment 3. The work vehicle bus system 15 has a work vehicle bus interface 19, which is connected to an attachment bus interface 20 of the attachment bus system 21. The attachment bus system 21, which is preferably also implemented as an ISOBUS, communicates with the control unit 17 of the attachment 3.

[0072] The pump 14 of the tractor 2 supplies hydraulic fluid in a supply line 22, which is connected via a work vehicle supply interface 23 to an attachment supply interface 24 of the attachment 3. The attachment supply interface 24 is connected via a supply line 25 to the hydraulic unit 18 for supplying the latter under the control of the control unit 17.

[0073] The front loader 4 has a hydraulic system 26 and an implement bus system 27, which is preferably designed as an ISOBUS. A supply line 28 of the hydraulic system 26 is connected to a supply line 31 of the tractor 2 via a connection between an implement supply interface 29 and a work vehicle supply interface 30, which is supplied with hydraulic fluid by the pump 14.

[0074] The attachment bus system 27 is connected to the work vehicle bus system 15 for bidirectional communication via the connection of an attachment bus interface 32 to a work vehicle bus interface 33.

[0075] The front loader 4 has a control unit 34 connected to the attachment bus system 27. The front loader 4 has a valve device 35. The valve device 35 can be designed as a single valve unit with a common housing or as several flanged valve modules. It is also possible for the valve device 35 to be designed with several valve units distributed throughout the front loader 4, which are connected to one another via hydraulic lines. The valve unit 35 is supplied with a hydraulic supply pressure and a hydraulic volume flow via the hydraulic system 26.

[0076] For the illustrated embodiment, the front loader 4 has a lifting cylinder 36 and a tilting cylinder 37, each designed as a double-acting cylinder. The pressure chambers of the lifting cylinder 36, 37 are each subjected to control pressures, which are controlled by the valve device 35 under the control of the control unit 34. The purpose of this is to initiate the actuating movements of the lifting cylinder 36 and the tilting cylinder 37 or to maintain them in a predetermined operating position.

[0077] The lifting cylinder 36 has pressure sensors 38, 39, each of which is assigned to a pressure chamber of the lifting cylinder 36. Furthermore, the lifting cylinder 36 has a motion sensor 40 that detects the travel of the lifting cylinder 36.

[0078] The tilt cylinder 37 has pressure sensors 41, 42, each of which is assigned to a pressure chamber of the tilt cylinder 37. Furthermore, the tilt cylinder 37 has a motion sensor 43, which detects the travel of the tilt cylinder 37.

[0079] A motion sensor 44 can detect the movement of the rocker arm, in particular a pivot angle of the rocker arm relative to the column of the front loader 4. It is also possible for a motion sensor 45 to detect the movement of the tool 5 relative to a tool holder of the front loader 4, which can also be a pivot angle.

[0080] The pressure sensors 38, 39, 41, 42 and the motion sensors 40, 43, 44, 45 communicate with the attachment bus system 27.

[0081] The tool 5 also has a control unit 46. The control unit 46 controls a valve device 47 of the tool 5. The valve device 47 controls the control pressures for an aggregate of the tool 5, in this case, control pressures for pressure chambers of an actuating cylinder 48. The actuating cylinder 48 has pressure sensors 49, 50 for detecting the pressures in the pressure chambers and a motion sensor 51 for detecting the travel of the actuating cylinder 48.

[0082] The tool 5 has a hydraulic system 52. A supply line 53 of the hydraulic system 52 provides hydraulic fluid for the valve device 47. The supply line 53 is connected to the hydraulic system 26 of the front loader 4 (and via it to the hydraulic system 13 and the pump 14 of the tractor 2) via a connection of a tool supply interface 54 and an attachment supply interface 55.

[0083] The tool 5 has a tool bus system 56, which is particularly designed as an ISOBUS. The tool bus system 56 communicates with the pressure sensors 49, 50 and the motion sensor 51. Furthermore, the tool bus system 56 communicates with the control unit 46.

[0084] The tool bus system 56 communicates with the attachment bus system 27 (and via this with the work vehicle bus system 15) via the connection of a tool bus interface 57 with an attachment bus interface 58.

[0085] The lifting cylinder 36, the tilting cylinder 37 and the actuating cylinder 48 form hydraulic actuators 59, the hydraulic actuation of which is controlled within the scope of the invention via the attachment bus system 27.

[0086] Preferably, the front loader 4 according to the invention (in addition to any bus interfaces and electrical connections) exclusively has at least one hydraulic supply connection, but not a further hydraulic connection for transmitting a hydraulic control pressure from the tractor 2 to the front loader 4.

[0087] It is possible for the control unit of the front loader 4 to automatically activate and / or deactivate the headlights of the front loader 4, which can occur depending on the motion sensors of the front loader 4, in particular depending on a lifting height. The headlights can be used, for example, to illuminate a target in the area in which unloading, for example tipping a bucket, is to take place. A headlight can be attached to a cross tube in front of the boom, which is guided by a parallel guide so that the alignment of the headlight relative to the ground does not change. It is possible for the headlight to then only be activated when a minimum lift is reached, which then illuminates the target area and allows the bucket to be tipped into the illuminated target area.

[0088] Fig. 2shows a detail of a front loader 4 with a tool holder 60, a rocker 61 with two parallel rocker struts 62, 63, and associated tilt cylinders 37a, 37b. The rocker struts 62, 63 are connected to one another in the front end region via a cross strut 64. The control unit 34 and the valve device 35 are held on the cross strut 64, wherein these are preferably flanged to one another. The control unit 34 and the valve device 35 are covered by a cover 65 (preferably at least upwards and / or downwards). It is possible for the cover 65 to be hinged open or otherwise detachable to allow access to the control unit 34 and / or the valve device 35.

[0089] If a tractor 2 is referred to here, the statements can apply accordingly to any other work vehicle, and a corresponding replacement can be made. If a front loader 4 is referred to here, the statements can apply accordingly to any other attachment, in particular a wheel loader bucket, a mower, a plow, etc., and a corresponding replacement can be made. If the hydraulic actuators of the front loader 4 are referred to as a lifting cylinder or a tilting cylinder, the statements can apply accordingly to any other actuating cylinder, any hydraulic actuator, or any hydraulic unit.

[0090] The invention relates to an attachment 67 for a work vehicle 66, having at least two hydraulic actuators 59, wherein the attachment 67 has a hydraulic attachment supply interface 24 which is designed to be connected to a hydraulic system 13 of the work vehicle 66, wherein the attachment 67 further has an attachment bus interface 32 which is designed to be connected to the work vehicle bus system 15 of the work vehicle 66, wherein the attachment supply interface 24 is designed to supply the attachment 67 with hydraulic fluid provided by the work vehicle 66 and wherein the attachment bus interface 32 is designed to transmit electrical or electronic control commands for actuating the at least two hydraulic actuators 59 of the attachment 67.

[0091] The valve device 35 has at least two control valves with which hydraulic fluid provided by the work vehicle 66 can be forwarded for control and supply to the at least two hydraulic actuators 59, in particular the lifting cylinder 46 and the tilting cylinder 37, in the form of control pressures for the pressure chambers, wherein the at least two control valves are controlled by the control unit 34.

[0092] It is particularly preferred if the valve device 35 has exactly two or exactly three control valves for controlling two or three hydraulic actuators of the attachment 67. A valve device 35 with three control valves is relatively compact and can thus be easily accommodated on an attachment 67. At the same time, if such a valve device 35 were mounted on the work vehicle 66, embodiments according to the prior art would already require the connection of two or three hydraulic supply lines (each with a forward line and a return line) or two or three pairs of control lines for the three hydraulic actuators.For an embodiment proposed here, the use of a (single) hydraulic supply interface and the electronic bus interface is sufficient, thus reducing the number of connections that must be made when attaching the attachment to the work vehicle.

[0093] For one proposal, the attachment is a wheel loader bucket carrier, and the tool is a bucket. A first control valve of the valve device is then configured to actuate a hydraulic actuator for raising and lowering or tilting the bucket. A second control valve can then be configured to actuate a hydraulic actuator for raising and lowering the wheel loader bucket carrier. A further control valve is preferably available to actuate an additional, undefined / flexibly configurable function of the attachment.

[0094] The valve device preferably has a hydraulic branch, with which hydraulic fluid provided via the hydraulic supply interface to the attachment 67 is supplied to the hydraulic actuators of the attachment 67 as needed. Preferably, the control valves each have two ports A and B, to each of which hydraulic fluid can be supplied as needed, with hydraulic fluid then being received in the other port B or A. Preferably, the hydraulic supply interface has a port P, to which pressurized hydraulic fluid is supplied, and a port T, via which hydraulic fluid can flow back into a tank of the work vehicle 66.The valve device 35 with the control valves is designed to distribute the pressurized hydraulic fluid provided at P to the individual connections A and B of the individual hydraulic actuators as required, in accordance with the control commands that the control valves receive from the control unit 34.

[0095] It is possible that the attachment 67 has exactly the one hydraulic supply interface described. Conventional attachments often have multiple (separate) hydraulic supply interfaces for multiple hydraulic actuators. A valve device 35 with control valves for operating the hydraulic actuators of the attachment 67 is then usually mounted on the work vehicle. This concept can be abandoned here: according to a concept proposed here, the attachment 67 has its own control unit 34, and the hydraulic interface serves (only) to provide pressurized hydraulic fluid as an energy source.

[0096] Preferably, only one electronic interface, in particular the attachment bus interface 32, is configured to transmit control commands for actuating the at least two hydraulic actuators from the work vehicle 66 to the attachment 67. Preferably, all information relating to the operation of the attachment 67 or the hydraulic actuators of the attachment 67 is transmitted via the electronic interface, in particular the attachment bus interface 32, and thus via the work vehicle bus system 15.

[0097] Preferably, the attachment 67 forms a self-contained system with the control unit 34, which communicates with the work vehicle bus system 15 via the attachment bus interface 32.

[0098] An operating system is preferably operated on the control unit 6 of the work vehicle 66, on which computer program products 68 associated with the attachment 67 can be installed or operated. The computer program product 68 described here is preferably programmed and configured specifically for the respective specific attachment 67.

[0099] The operating device 9 of the work vehicle 66 is, for example, a joystick 10 permanently installed in the work vehicle 66. With the computer program product 68, it is possible to use such a joystick 10 or another operating device permanently provided in the work vehicle 66 to control the attachment 67. In particular, the installation of special operating devices for the respective attachment 67 in the work vehicle can be dispensed with.

[0100] Particularly preferably, the computer program product 68 is configured to display functions of the attachment 67 for an operator on a display or display device 7 of the work vehicle 66.

[0101] The described attachment 67 and the computer program product 68, 69 define a novel interface between attachments 67 and work vehicles 66. Communication with the work vehicle 66 is realized via the work vehicle bus system 15. The HMI devices present in the work vehicle 66 (operating devices such as joysticks, displays present in the work vehicle, or the bus infrastructure present there) are used to control the attachment 67. A display in the work vehicle 66 can be used, in particular, for an operator to select and visualize the functionalities of the attachment 67.

[0102] The control unit 34 of the attachment 67 controls the control valves of the valve assembly 35 of the attachment 67 and detects the current status of the attachment 67 using the described sensors. Based on this information, together with the current control commands transmitted via the work vehicle bus system 15, the control unit 34 calculates new setpoint commands for the control valves in the valve assembly 35 of the attachment 67.

[0103] On the control unit 6 of the work vehicle 66 is a computer program product 68 or the control unit 34 of the attachment 69 is a computer program product 69 installed, which enables an operator to control or actuate / operate the attachment 67 via the operating device 9 of the work vehicle 66. Preferably, the computer program product 68, 69 is also configured to output information about the operation / actuation and, if applicable, the status of the attachment 67 and its hydraulic actuators on the display device 7 of the work vehicle 66.

[0104] It is possible that the attachment 67 can basically be operated autonomously with Provision of the supply of hydraulic fluid from the work vehicle 66 and provision of the electrical or electronic control signals which are transmitted from the work vehicle 66 to the attachment 67 via the attachment bus interface 32, transmission of operating variables of the attachment 67, in particular based on the measurement signals from the pressure sensors and / or motion sensors, via the attachment bus interface 32 from the attachment 67 to the work vehicle, electrical power supply between the work vehicle 66 and the attachment via a suitable plug or a power supply connection. LIST OF REFERENCE SYMBOLS

[0105] 1Vehicle combination 2Tractor 3Attachment 4Front loader 5Tool 6Control unit 7Display device 8Screen 9Operating device 10Joystick 11Engine 12Transmission 13Hydraulic system 14Pump 15Work vehicle bus system 16ISOBUS 17Control unit 18Hydraulic unit 19Work vehicle bus interface 20Attachment bus interface 21Attachment bus system 22Supply line 23Work vehicle supply interface 24Attachment supply interface 25Supply line 26Hydraulic system 27Attachment bus system 28Supply line 29Attachment supply interface 30Work vehicle supply interface 31Supply line 32Attachment bus interface 33Work vehicle bus interface 34Control unit 35Valve assembly 36Lifting cylinder 37Tilt cylinder 38Pressure sensor 39Pressure sensor 40Motion sensor 41Pressure sensor 42Pressure sensor 43Motion sensor 44Motion sensor 45Motion sensor 46Control unit 47Valve assembly 48Actuating cylinder 49Pressure sensor 50Pressure sensor 51Motion sensor52Hydraulic system 53Supply line 54Tool supply interface 55Attachment supply interface 56Tool bus system 57Tool bus interface 58Attachment bus interface 59Hydraulic actuator 60Tool holder 61Swing arm 62Swing arm strut 63Swing arm strut 64Cross brace 65Cover hood 66Work vehicle 67Attachment 68Computer program product 69Computer program product

Claims

1. An attachment (67), in particular a front loader (4), comprising a) a hydraulic system (26) with at least two hydraulic actuators (59) and b) an attachment bus system (27) having an attachment bus interface (32) via which the attachment bus system (27) can be connected to a work vehicle bus system (15), c) wherein the attachment bus system (27) is directly or via a control unit (34) of the attachment (67) ca) coupled to pressure sensors (38, 39, 41, 42) in such a way that measurement signals from the pressure sensors (38, 39, 41, 42) or signals dependent thereon can be transmitted via the attachment bus system (27), and / or cb) coupled to motion sensors (40, 43) in such a way that measurement signals from the motion sensors (40, 43) or signals dependent thereon can be transmitted via the attachment bus system (27).

2. Attachment (67) according to claim 1, wherein a) the attachment (67) has an electronically controlled valve device (35), b) the attachment (67) has a hydraulic attachment supply interface (29) which is connected to the electronically controlled valve device (35) of the attachment (67), and c) the valve device (35) controls or regulates the hydraulic application of the hydraulic actuators in dependence on information transmitted via the attachment bus system (27).

3. Attachment (67) according to one of the preceding claims, wherein the attachment (67) a) has a stroke sensor which detects the stroke of a lifting cylinder (36) of the attachment (67), and / or b) has a tilting path sensor which detects the tilting path of a tilting cylinder (37) of the attachment (67), and / or c) has a pressure sensor (38, 39, 41, 42) which detects a pressure with which a pressure chamber of a hydraulic actuator, in particular of the lifting cylinder (36) or the tilting cylinder (37), is acted upon, and / or d) a pair of pressure sensors (38, 39;41, 42) which detect the pressures with which oppositely acting pressure chambers of a double-acting hydraulic actuator, in particular of the lifting cylinder (36) or tilting cylinder (37), are acted upon, and / or e) an angle sensor which detects a pivot angle of a rocker of the attachment (67) relative to a column of the attachment (67), and / or f) an angle sensor which detects a pivot angle of a tool holder of the attachment (67) relative to a rocker of the attachment (67); 4. Attachment (67) according to one of the preceding claims, wherein the attachment bus system (27) has a tool bus interface (57) via which the attachment bus system (27) can be connected to a tool bus system (56).

5. Attachment (67) according to one of the preceding claims, wherein the attachment (67) has a further attachment bus system, wherein the attachment bus system (27) and the further attachment bus system are connected to one another via a control unit (34).

6. Vehicle combination (1) with a) a work vehicle (66), in particular a tractor (2), which has a work vehicle bus system (15) which communicates with an operating device (9) of the work vehicle (66) and has a work vehicle bus interface (33), and b) an attachment (67), in particular a front loader (4), according to one of claims 1 to 5, c) wherein the work vehicle bus system (15) and the attachment bus system (27) are coupled to one another via a connection of the work vehicle bus interface (33) to the attachment bus interface (32).

7. Attachment (67) according to one of claims 1 to 5 or vehicle combination (1) according to claim 6, wherein the work vehicle (66) and / or the attachment (67) has / has a control unit (6, 34) with control logic which coordinates an operation of the work vehicle (66) and an operation of the attachment (67) via the attachment bus interface (32).

8. Attachment (67) or vehicle combination (1) according to claim 7, wherein the control logic is designed such that a) pressure regulation of the pressures in the lifting cylinder (36) and / or tilting cylinder (37) and / or a hydraulic actuator (59) takes place and / or b) a determination of a load carried by the attachment (67) and / or a coordinate of a center of gravity of a load carried by the attachment (67) takes place and / or c) a lifting speed and / or tilting speed is controlled or regulated as a function of a load and / or d) at least one predetermined operating state or operating state profile of the attachment (67) is stored and the stored predetermined operating state or operating state profile is automatically brought about and / or e) an automatic oscillating movement of a tool holder of the attachment (67) can be brought about and / or f) automatic vibration damping of the attachment (67) takes placeand / or g) a control and / or regulation of the distribution of a supply flow of the hydraulic fluid to the lifting cylinder (36), the tilting cylinder (37) and / or at least one hydraulic actuator (59) is carried out and / or h) a control and / or regulation of a parallel guidance of a tool holder is carried out and / or i) a limitation of an actuating travel of the lifting cylinder (36) and / or an actuating travel of a tilting cylinder (37) and / or a hydraulic actuator (59) is carried out and / or j) damping is brought about in the region of an end position of an actuating travel of the lifting cylinder (36) and / or a tilting cylinder (37) and / or a hydraulic actuator (59) and / or k) a reduction of the movements of a tool holder and / or a chassis of the work vehicle (66) when the vehicle combination (1) is traveling on an uneven road surface is controlled or regulated and / or l) a locking and / or unlocking of a locking device for the locking onetool with the tool holder of the work vehicle (66) and / or m) an automatic activation and / or deactivation of an all-wheel drive of the work vehicle (66) takes place as a function of an operating state of the work vehicle (66) and / or n) an automatic adjustment of a maximum travel speed of the work vehicle (66) from a load carried by the attachment (67) takes place and / or o) a predetermined dependency of an angle of the tool holder on the travel of the lifting cylinder (36) is brought about and / or p) a speed scaling function is carried out and / or q) a speed mode is ensured and / or r) a float function is provided and / or s) a control of a pump of the work vehicle (66) takes place as a function of a load carried by the attachment (67).

9. Attachment (67) or vehicle combination (1) according to one of the preceding claims, wherein a tool database is present in which a) specific characteristic data of tools that can be coupled to a tool holder of the attachment (67) and / or b) specific characteristic data of attachments (67) can be stored.

10. Attachment (67) or vehicle combination (1) according to one of the preceding claims, wherein the attachment (67) receives a control variable via the attachment bus interface (32), which is predetermined in particular via an operating device (9) or a joystick (10) of the work vehicle (66) or a control unit (6) of the work vehicle (66), and the control unit (34) of the attachment (67) has control logic which controls the valve device (35) of the attachment to generate the hydraulic actuation of the lifting cylinder (36), the tilting cylinder (37) and / or the actuator (59) taking into account the received control variable and a) specific characteristic data of a tool which is coupled to a tool holder of the attachment (67), and / or b) specific characteristic data of the geometry of the attachment (67) and / or c) specific characteristic data of the lifting cylinder (36), the tilting cylinder (37) and / or the Actuator (59) is controlled.

11. Attachment (67) or vehicle combination (1) according to one of the preceding claims, wherein the attachment (67) has an interface via which operating data of the attachment (67), in particular a load determined by the attachment (67), can be transmitted.

12. Computer program product (68; 69) configured for operation on a control unit (6) of a work vehicle (66), in particular a tractor (2), which is configured for mounting an attachment (67), in particular a front loader (4), according to one of the preceding claims, or a control unit (34) of an attachment, wherein the computer program product (68; 69) is configured to enable an operator to control the attachment (67) with an operating device (9) of the work vehicle (66) via control commands and to transmit the control commands for controlling hydraulic actuators (59) of the attachment (67) via a work vehicle bus system (15), a work vehicle bus interface (33), an attachment bus interface (32) to an attachment bus system (27).

13. Computer program product (68; 69) according to claim 12, configured to display functions or operating states or measurement signals from pressure sensors (38, 39, 41, 42) or motion sensors (40, 43) of the attachment (67) or a tool held thereon for an operator on a display device (7) of the work vehicle (66).

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