Self-propelled agricultural work vehicle

Abstract

A self-propelled agricultural work vehicle (14), in particular for sowing crops or for soil cultivation, is described, which has a steerable front axle (20) attached to a frame and a steerable rear axle (22) attached to the frame, the front wheels (16) and rear wheels (18) of which are equipped with individual wheel drive, wherein the two front wheels (16) each have a steering knuckle (30) oriented towards the center of the vehicle, which are connected to each other via a first crossbar (32), and the two rear wheels (18) each have a steering knuckle (30) oriented towards the center of the vehicle, which are connected to each other via a second crossbar (34), wherein the steering is controlled by a change in the rotational speed of the front wheels (16) and the rear wheels (18).

Description

[0001] The invention relates to a self-propelled agricultural work vehicle, in particular for sowing crops or for soil cultivation.

[0002] Self-driving agricultural work vehicles, also known as robots, are already known from the state of the art.

[0003] AT 512557 A1 describes an agricultural machine consisting of a self-propelled, self-steering vehicle with four wheels and electric drive and a suitable control system, wherein each wheel is driven by its own electric drive, and wherein the vehicle is controlled by means of a front steering system and a rear steering system consisting of a steering axle, steering axle lever, steering linkage and steering lever.

[0004] EP 4194235 A1 discloses an agricultural vehicle comprising a chassis, a front axle comprising two steerable front wheels and an independent front suspension for each of the front wheels, a steering mechanism for steering the front wheels, wherein during a steering maneuver the front wheels define an inner front wheel and an outer front wheel which are closer and farther away respectively with respect to a steering center, a control unit configured to perform the steering maneuver, a rear axle comprising two rear wheels, a drive train arranged to drive at least some of the front and rear wheels, wherein the front axle has for each of the front wheels an actuator which serves to raise and lower the corresponding front wheel with respect to the chassis.

[0005] EP 4248724 A1 relates to a robot and a method for the autonomous cultivation of an agricultural area with plants arranged in rows, with a chassis having two axles which are connected to each other only by a central crossbeam, wherein each axle is arranged on the crossbeam so as to be steerable about a pivot axis and wherein each axle has two steerable wheels which are rotatable about a steering axis and at least one of which is driven.

[0006] From WO 2023 / 223353 A1, an agricultural robot for use in agricultural fields is known. The robot comprises a chassis, a steering system, a front suspension system, a primary drive train, a secondary drive train, an implement coupling system, and an actuator for adjusting the implement position. The robot precisely identifies weeds and removes them optimally in real time. The compact robot is robust and highly maneuverable, allowing it to operate with a small turning radius even in confined spaces. It eliminates the high operating costs of conventional machinery such as tractors, weed killers, rotary tillers, sprayers, and similar equipment. The compact robot can be used in fields with closely spaced crops. It can remove weeds located in close proximity to the crops.

[0007] Based on this state of the art, the inventor(s) have now set themselves the task of creating a robot with improved steering characteristics.

[0008] This problem is solved by independent claim 1. Further advantageous embodiments of the invention are the subject of the dependent claims. These can be combined with one another in a technologically meaningful manner. The description, particularly in conjunction with the drawing, further characterizes and specifies the invention described in the claims.

[0009] According to the invention, a self-propelled agricultural work vehicle, in particular for sowing crops or for soil cultivation, is provided, which has a steerable front axle and a steerable rear axle attached to a frame, the front and rear wheels of which are equipped with individual wheel drive, wherein the two front wheels each have a steering knuckle oriented towards the center of the vehicle, which are connected to each other via a first crossbar, and the two rear wheels each have a steering knuckle oriented towards the center of the vehicle, which are connected to each other via a second crossbar, wherein the steering is controlled by a change in the rotational speed of the front and rear wheels.

[0010] The work vehicle according to the invention is equipped with individual wheel drive at the front and rear wheels. Similar to a conventional kingpin steering system, both the front and rear wheels are each provided with a steering knuckle oriented towards the center of the vehicle. These steering knuckles are connected to a crossbar for both the front and rear axles, resulting in a trapezoidal shape consisting of the crossbar, steering knuckle, and the respective axle. However, the crossbar is not connected to a steering gear or an actuator. According to the invention, steering is achieved by changing the rotational speed of the front or rear wheels. This steering design makes the vehicle's load irrelevant, allowing the maximum power of the drive system to be used for steering.

[0011] According to one embodiment of the invention, the front axle is a rigid axle.

[0012] This approach results in precise guidance of work equipment, which – like the rigid axle – is mounted without any displacement relative to the work vehicle.

[0013] According to a further embodiment of the invention, the rear axle is designed as a pendulum axle.

[0014] It has been found that a pendulum axle leads to better traction of the work vehicle, especially in rough terrain or on uneven ground.

[0015] According to a further embodiment of the invention, the arrangement of front axle, steering knuckle and first crossbar and the arrangement of rear axle, steering knuckle and second crossbar are based on the Ackermann principle.

[0016] The Ackermann principle, as is well known, describes the steering angle deviations of the inner and outer wheels when traversing a circular path. The term "orientation" here means that the steering angles can deviate slightly from the specified position. Because no steering gear is used, the wheels can turn so far that a change in rotational speed alone would no longer be able to correct the steering and would lock the corresponding axle. However, by deliberately deviating from the Ackermann principle, this situation is shifted towards larger steering angles.

[0017] According to a further embodiment of the invention, the inner wheel turns too little compared to the Ackermann principle, and the outer wheel follows the Ackermann principle.

[0018] The arrangement of front axle, steering knuckle and first crossbar and the arrangement of rear axle, steering knuckle and second crossbar are designed according to the Ackermann principle, but are optimized in this way in such a way that an “overshoot” is only reached at a late point in time, i.e. at larger steering angles.

[0019] According to a further embodiment of the invention, the front wheels and the rear wheels are each provided with a pivot arm which can be pivoted about a pivot point located at the end of the front axle or at the end of the rear axle.

[0020] In this way, the ground clearance of the work vehicle can be increased, since the arrangement of front axle, steering knuckle and first crossbar and the arrangement of rear axle, steering knuckle and second crossbar can be offset upwards by the axial length of the pivot arms relative to the center of the wheels.

[0021] According to a further embodiment of the invention, each front wheel and each rear wheel has an electric motor mounted below the swivel arm.

[0022] As described above, the electric motor is controlled to drive the wheels in such a way that the desired steering movement can be achieved. The placement of the electric motor on the swivel arm allows the desired torque to be transmitted to the wheels.

[0023] According to a further embodiment of the invention, the frame is a central beam arranged longitudinally.

[0024] In this way, a weight-optimized design of the work vehicle is achieved.

[0025] According to a further embodiment of the invention, an agricultural implement is attached to the central frame behind the front axle.

[0026] Particularly in combination with the front axle designed as a rigid axle, precise guidance of the work equipment is possible in this way.

[0027] According to a further embodiment of the invention, the working tool is interchangeable.

[0028] In this way, the work vehicle according to the invention can be used for various processing tasks. These include, among others, the application of seeds, fertilizers or plant protection products, as well as soil cultivation for loosening or weed control.

[0029] According to a further embodiment of the invention, the central beam has a centering means into which the working tool is suspended.

[0030] This means that precise positioning relative to the central beam of the work vehicle is possible, and this positioning can be reproduced even after changing the work equipment.

[0031] According to a further embodiment of the invention, the work device extends beyond the work vehicle and can be pivoted upwards.

[0032] In this way, the working width of the work vehicle can be increased, whereby the passage width is not significantly changed when encountering obstacles due to the pivoting of the work device.

[0033] According to a further embodiment of the invention, at least the central beam is made of bent sheet metal.

[0034] This enables cost-effective manufacturing, which is also weight-optimized.

[0035] According to a further embodiment of the invention, the front axle and the rear axle are also made of bent sheet metal.

[0036] This also enables cost-effective manufacturing, which is also weight-optimized.

[0037] According to a further embodiment of the invention, the track width of the front axle and the rear axle is adjustable in discrete steps.

[0038] In this way, the track width of the work vehicle can be changed depending on the desired application without having to provide different frame components.

[0039] According to a further embodiment of the invention, the work vehicle has a solar roof mounted on the top, which is divided into two sections along the longitudinal direction, and which can be folded individually.

[0040] The solar roof can supply electrical energy to the batteries that power the electric motor. When folded up, it allows access to components underneath the vehicle. Furthermore, this design allows for a narrow passage width while maintaining a large solar roof area, as the roof can extend beyond the vehicle. The two halves of the solar roof can also be extended at multiple levels, resulting in an even larger solar roof area.

[0041] According to a further embodiment of the invention, the work vehicle has a storage container below the solar roof.

[0042] The storage container can be used for seeds or fertilizer, and easy filling is possible thanks to the aforementioned folding up of the solar roof.

[0043] Furthermore, a refilling system is provided with a self-propelled agricultural work vehicle, in particular as described above, and with a container that can be coupled to the work vehicle with a storage container, in particular via a screw conveyor, so that spreading particles can be transferred from the container of the refilling system to the storage container.

[0044] The work vehicle can autonomously proceed to the refilling system and connect to the hopper as soon as the fill level of the storage hopper falls below a predefined threshold. This threshold can also be set by a control unit, which calculates, based on track lengths, application rate, and the hopper fill level, whether the work vehicle still has sufficient supply to continue working or needs to return to the refilling system.

[0045] Some exemplary embodiments are explained in more detail below with reference to the drawing. The drawing shows: Fig. 1 a first embodiment of a work vehicle according to the invention in a perspective side view, Fig. 2 a schematic view of the steering geometry of the work vehicle Fig. 1, Fig. 3 in a perspective view a detailed view of a wheel on its axle of the work vehicle Fig. 1, Fig. 4 in a perspective view a detailed view of a central beam of the work vehicle Fig. 1, Fig. 5 in a perspective view a detailed view of a fastening for work equipment of the work vehicle Fig. 1, and Fig. 6 in a perspective view another of the work vehicle from Fig. 1.

[0046] In the figures, identical or functionally equivalent components are provided with the same reference symbols.

[0047] In Fig. Figure 1 shows a first embodiment of a work vehicle 14 according to the invention in a perspective side view. The work vehicle 14 has front wheels 16 and rear wheels 18. The front wheels 16 are arranged on a front axle 20 and the rear wheels 18 on a rear axle 22. Each front wheel 16 and each rear wheel 18 is driven by its own electric motor 24, which is mounted in the hub of the respective wheel. The speed of each electric motor 24 is individually controlled by a control unit in the form of an individual wheel drive. The front axle 20 and the rear axle 22 are attached to a central beam 26 as a frame, which is arranged centrally along the longitudinal direction of the work vehicle 14. On its upper surface, the work vehicle has a solar roof 28, which is divided into two halves in the area and along the central beam 26.

[0048] A characteristic feature of the work vehicle 14 according to the invention is its steering system. This will be described below with reference to the Fig. 2 explained in detail.

[0049] The two front wheels 16 each have a steering knuckle 30 oriented towards the center of the vehicle, which are connected to each other via a first crossbar 32. The steering knuckle 30 is rotatable with respect to both the front axle 20 and the first crossbar 32 via a corresponding articulated connection. The two rear wheels 18 also have a steering knuckle 30 oriented towards the center of the vehicle, which are connected to each other via a second crossbar 34. The steering of the work vehicle 14 is controlled exclusively by changing the rotational speed of the front wheels 16 and the rear wheels 18. Neither the first crossbar 32 nor the second crossbar 34 is connected to a steering gear or an actuator.

[0050] The arrangement consisting of the front axle 20, steering knuckle 30, and first crossbar 32, as well as the arrangement consisting of the rear axle 22, steering knuckle 30, and second crossbar 34, exhibits the typical trapezoidal shape, which can be dimensioned such that the steering geometry follows the Ackermann principle. However, according to the invention, a different approach is taken. While the arrangement consisting of the front axle 20, steering knuckle 30, and first crossbar 32, as well as the arrangement consisting of the rear axle 22, steering knuckle 30, and second crossbar 34, are based on the Ackermann principle, the wheel steering is such that, when cornering, the inner wheel turns less than the Ackermann principle would, while the outer wheel follows the Ackermann principle.

[0051] In Fig. Figure 3 shows a front view of the work vehicle 14. It can be seen that the front wheels 16 are connected to the steering knuckles 30 via pivot arms 36. This increases the ground clearance of the work vehicle 14, as the first crossbar 32 and the axle 20 can be guided above the pivot arms 36. The rear wheels 18 on the rear axle 22 are arranged according to the same principle, with pivot arms 36 also provided between the steering knuckles 30 and the rear wheels 18. For optimal torque transmission, the electric motor 24 is connected to the respective wheels 16 and 18 at the hub.

[0052] In Fig. Figure 4 shows a side view of the work vehicle 14 with only the components arranged below the central beam 28. According to one embodiment of the invention, the front axle 20 is a rigid axle. This results in precise guidance of work implements, which, like the rigid axle, are attached to the central beam 26 without any displacement relative to the work vehicle. The rear axle 22 is designed as a pendulum axle. It has been found that a pendulum axle leads to better traction of the work vehicle 14, particularly in rough terrain or on uneven ground.

[0053] In Fig. Figure 5 shows a detailed view of the attachment of the implement to the central link 26. The central link 26 interacts with a centering element 40 in the form of a plate, over which the implement is suspended and which supports it. The implement can extend beyond the vehicle 14 and be pivotable upwards. Here, the implement is represented only by a bracket 44 and top link 46.

[0054] The work vehicle 14 is in Fig. Figure 6 shows another perspective side view. It can be seen that the work vehicle 14 has the solar roof 28 mounted on its upper surface, which is divided lengthwise into two halves. Both halves can be folded independently. The batteries for operating the electric motor 24 can be supplied with electrical energy through the solar roof 28. When folded up, it allows access to components on the work vehicle 14 located underneath. Furthermore, this design allows the passage width to be kept small while maintaining a large surface area for the solar roof 28, which can extend beyond the work vehicle 14.

[0055] The work vehicle 14 below the solar roof 28 has a storage container 42, which is in Fig. Figure 4 shows the storage container 42, which can be used for seeds or fertilizer, and can be easily filled by folding up the solar roof 28 as mentioned above.

[0056] The central frame member 28, the front axle, and the rear axle are made of bent sheet metal. This allows for cost-effective manufacturing, which is also weight-optimized. Other manufacturing methods are also possible.

[0057] According to a further embodiment of the invention, the track width of the front axle 20 and the rear axle 22 is adjustable in discrete steps. In this way, the track width of the work vehicle 14 can be changed depending on the desired application without having to provide different frame components. For this purpose, the components in Fig. The 6 screws shown 48 are used to fix the two sliding parts of the axle to each other.

[0058] The self-propelled agricultural work vehicle 14 can also operate with a refilling system with a container that can be connected to the work vehicle's storage container 42, for example, via a screw conveyor, so that free-flowing particles are transferred from the refilling system's container to the storage container 42. Powdered or liquid materials can also be processed. The work vehicle 14 can autonomously move to the refilling system and connect to the container as soon as the fill level of the storage container 42 falls below a predefined threshold.

[0059] The features specified above and in the claims, as well as those discernible from the illustrations, can be advantageously implemented both individually and in various combinations. The invention is not limited to the described embodiments but can be modified in many ways within the scope of expert knowledge. List of reference symbols: 14 work vehicles 16 front wheel 18 rear wheel 18 rear wheels 20 front axle 22 Rear axle 24 Electric motor 26 Central beam 28 solar roof 28 Central beam 30 axle stubs 32 first crossbar 34 second crossbar 36 Swivel arm 40 centering devices 42 storage containers 44 bracket 46 Top links 48 screws QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] AT 512557 A1

[0003] EP 4194235 A1

[0004] EP 4248724 A1

[0005] WO 2023 / 223353 A1

[0006]

Claims

Self-propelled agricultural work vehicle (14), in particular for sowing crops or for soil cultivation, which has a steerable front axle (20) attached to a frame and a steerable rear axle (22) attached to the frame, the front wheels (16) and rear wheels (18) of which are equipped with individual wheel drive, wherein the two front wheels (16) each have a steering knuckle (30) oriented towards the center of the vehicle, which are connected to each other via a first crossbar (32), and the two rear wheels (18) each have a steering knuckle (30) oriented towards the center of the vehicle, which are connected to each other via a second crossbar (34), wherein the steering is controlled by a change in the rotational speed of the front wheels (16) and the rear wheels (18). Self-propelled agricultural work vehicle (14) according to claim 1, wherein the front axle (20) is a rigid axle. Self-propelled agricultural work vehicle (14) according to one of claims 1 or 2, wherein the rear axle (22) is designed as a pendulum axle. Self-propelled agricultural work vehicle (14) according to one of claims 1 to 3, wherein the arrangement of front axle (20), steering knuckle (30) and first crossbar (32) and the arrangement of rear axle (22), steering knuckle (30) and second crossbar (34) are based on the Ackermann principle. Self-propelled agricultural work vehicle (14) according to claim 4, in which the inner wheel turns less than the Ackermann principle and the outer wheel follows the Ackermann principle. Self-propelled agricultural work vehicle (14) according to one of claims 1 to 5, wherein the front wheels (16) and the rear wheels (18) are each provided with a pivot arm (36) which connects to the axle stubs (30) of the crossbars (32; 34) and is pivotable about a pivot point located at the end of the front axle (20) or at the end of the rear axle (22). Self-propelled agricultural work vehicle (14) according to one of claims 1 to 6, wherein each front wheel (16) and each rear wheel (18) has an electric motor (24) mounted in the center. Self-propelled agricultural work vehicle (14) according to one of claims 1 to 7, wherein the frame is a longitudinally arranged central beam (26). Self-propelled agricultural work vehicle (14) according to claim 8, in which an agricultural work implement is attached behind the front axle (20) to the central beam (26). Self-propelled agricultural work vehicle (14) according to claim 8 or 9, wherein the work implement is interchangeable. Self-propelled agricultural work vehicle (14) according to one of claims 8 to 10, wherein the central beam (26) interacts with a centering means (40) over which the work implement is suspended. Self-propelled agricultural work vehicle (14) according to one of claims 8 to 11, wherein the work implement extends beyond the work vehicle (14) and is pivotable upwards. Self-propelled agricultural work vehicle (14) according to one of claims 8 to 12, wherein at least the central beam (26) is made of bent sheet metal. Self-propelled agricultural work vehicle (14) according to claim 13, in which, furthermore, the front axle (20) and the rear axle (22) are made of bent sheet metal. Self-propelled agricultural work vehicle (14) according to one of claims 1 to 14, wherein the track width of the front axle (20) and the rear axle (22) is adjustable in discrete steps. Self-propelled agricultural work vehicle (14) according to one of claims 1 to 15, which has a solar roof (28) mounted on the top side, which is divided into two sections about the longitudinal direction, which can be folded individually. Self-propelled agricultural work vehicle (14) according to claim 16, which has a storage container (42) below the solar roof (28). Refilling system with a self-propelled agricultural work vehicle (14), in particular according to one of claims 1 to 17, and with a container which can be coupled to the work vehicle (14) with a storage container (42), in particular via a screw conveyor, so that spreading particles can be transferred from the container of the refilling system to the storage container. Refilling system according to claim 18, wherein the work vehicle (14) independently goes to the container and couples as soon as the fill level of the storage container (42) falls below a predetermined threshold.

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