Load carrier transport unit with compact roller arrangement

Abstract

The invention relates to a conveyor unit (1) for conveying material carriers, comprising: an elongated frame structure (2) having a front frame section (2A) and a rear frame section (2B), each of which has a roller device (5), the roller device is provided with at least two rollers (6) which are rotatably mounted around a vertical rotation axis (D) relative to the frame structure (2); and a carrier element which can be brought into contact with the load carrier and which can be moved in the vertical direction relative to the frame structure (2) by means of a lifting device between a raised position and a lowered position; wherein each of the roller devices (5) has at least one roller (6) which can be driven by means of a roller drive (7) designed as a hub drive.

Description

Technical Field

[0001] The invention relates to a conveyor unit for conveying load carriers and also to a conveying device having a plurality, in particular two, of such conveyor units. Background Art

[0002] Freight carriers are usually used for transporting goods within an enterprise. The freight carriers can be transported by site transport equipment. It is driven underneath, lifted together with the goods supported thereon and lowered again at a specific location after transport. A known example of such a load carrier is the standard and reusable "Euro pallet".

[0003] The prior art already knows various forms of yard transport equipment, hereinafter referred to as conveyor systems. A distinction is therefore made between one-piece and multi-piece conveyor systems. In the former, such as the one-piece conveyor system shown in EP 2 336 075 A1, the sections of the conveyor system that travel beneath the load carrier are fixedly connected to one another. Multi-piece conveyor systems, such as those shown in DE 10 2007 046868 A1, typically comprise a first and second conveyor unit that are not physically connected to one another. Conveyor systems can also be distinguished in terms of their operation. On the one hand, manual or motor-driven operation is possible, as is the case, for example, with manual lifts commonly used for loading and unloading trucks. On the other hand, autonomous conveyor systems are also known; see again EP 2 336 075 A1 for this.

[0004] DE 10 2007 046 868 A1 proposes to achieve all necessary movements of a transport system using only one electric motor. This drive system requires a square base, which requires the same dimensions in both the full width and length of the material carrier. Furthermore, this embodiment with rollers and the accompanying arrangement does not allow travel perpendicular to the longitudinal axis of the conveyor unit, as otherwise the conveyor unit would tip over. Similar conveying devices are known, for example, from DE 10 2013 013684 A1, EP 3 216747 A2, and WO 2018 / 136987 A1. These drive systems all have two wheels that can rotate about a common rotation axis, which rotate about a vertical axis. The disadvantage of these drives is their space-intensive design and the impracticality of travel perpendicular to the longitudinal axis of the conveyor unit.

[0005] In autonomous conveyor systems that move completely under the load carrier to be transported, the perimeter provided by the respective load carrier, i.e., the space available to the conveyor system when entering or exiting under a load carrier parked on the ground, is a crucial limiting factor. Therefore, all components necessary for the function and operation of the conveyor system must be positioned within the available height, width, and length, with certain minimum height and width distances to the load carrier also having to be maintained in order to ensure smooth entry and exit. Summary of the Invention

[0006] The object of the present invention is to provide a conveyor unit or a conveyor device having a plurality of such conveyor units, which conveyor device has a compact roller arrangement and is movable in all directions.

[0007] This object is achieved by the subject matter of independent claim 1. The dependent claims define preferred embodiments of the invention.

[0008] Therefore, the conveying unit according to the invention for conveying a material carrier comprises:

[0009] an elongated frame structure having a front frame section and a rear frame section, each of the front frame section and the rear frame section having a roller arrangement with at least two rollers rotatably mounted relative to the frame structure about a vertical axis of rotation;

[0010] a support element which can be brought into contact with the load carrier and which can be moved in a vertical direction relative to the frame structure between a raised position and a lowered position by means of a lifting device;

[0011] Each of the roller arrangements has at least one roller, which can be driven by means of a roller drive designed as a wheel hub drive.

[0012] In other words, the functional components necessary for moving the conveyor unit are combined in a compact structural unit and accommodated in the individually driven rollers of the conveyor unit. It should be noted that it may be sufficient for only a single roller of the conveyor unit to have such a drive. It is also conceivable for all rollers of the conveyor unit to have such a drive.

[0013] In one embodiment, a roller drive designed as a wheel hub drive can be arranged within the roller's rotational trajectory circle. If the roller rotates around its vertical axis of rotation, the so-called rotational trajectory circle is defined by the travel surface of the associated roller. In other words, when the roller rotates, the area of the travel surface farthest from the axis of rotation marks the limit of the area or volume, which determines the maximum available structural volume for the roller drive. In other words, in each angular position of the roller, the roller travel surface is the element farthest from the roller's axis of rotation. This can apply, for example, to projections along the roller's axis of rotation, and also to the three-dimensional volume determined by a complete rotation of the roller around its axis of rotation.

[0014] In another embodiment, the roller drive may include an electric motor, a transmission coupling the electric motor and rollers, a brake that reacts to the electric motor's drive torque, and a control unit for controlling the electric motor. In particular, the electric motor, transmission, and brake are arranged coaxially with the roller's axis of rotation, which can extend substantially horizontally. The brake can also be arranged on the transmission input side, similar to the electric motor. Thus, the braking torque generated by the brake is converted by means of the transmission and, for example, acts at least indirectly on the transmission input shaft. Thus, the rollers arranged on the transmission output side experience a braking torque that is converted, particularly amplifying the transmission ratio. In particular, the brake can operate at the same speed as the electric motor and / or at a different speed than the rollers. Converting the braking torque via the transmission allows for the use of a smaller brake design, ultimately allowing the brake to be installed in the roller unit, particularly when the available space within the roller unit is limited.

[0015] It is also conceivable that the power electronics of the electric motor and / or any integrated rotation sensors are also included in the roller drive, thus also being located within the roller's rotational path. This embodiment minimizes the necessary wiring, which also has a positive impact on the compactness of the roller drive. Furthermore, for example, the wiring that ensures data and / or electrical coupling between the roller unit and other components of the conveyor unit can extend at least partially between an interface fixed to the conveyor unit's frame structure and an interface that rotates about its vertical rotation axis in response to the roller unit's rotational movement. To avoid stress on the wiring caused by the roller unit's rotational movement, the cables can be routed in the form of a cable loop between the aforementioned interfaces or other fastening devices that secure the cables to the frame structure or roller unit. The cable loop can encircle the roller unit's vertical rotation axis, in particular, essentially in a horizontal plane. Elements of the roller unit that rotate about the vertical rotation axis, in particular cable interfaces or cable fixing points, can be located in a vertical projection within the cable loop.

[0016] According to another embodiment, the bearing device for supporting the roller unit, formed by the rollers and the roller drive, relative to the frame structure is arranged within the roller's rotational path circle. It is also possible for only the roller's running surface to extend beyond the support plane. In particular, it is possible for the roller unit to be supported both above and below the roller's axis of rotation relative to the frame structure in the functionally dependent position of the conveyor unit. In other words, the roller unit is supported on the frame structure both above and below the roller's axis of rotation, in particular, with only the roller's running surface again projecting beyond the upper or lower horizontal support plane.

[0017] In summary, the rollers, in particular their running surfaces, are rings, along the bores of which all essential functional components, in particular all functional components, of the roller drive are arranged.

[0018] According to another embodiment, the vertical axis of rotation of the roller, which is required for "steering" the conveyor unit, is spaced apart from the center plane of the roller, in particular from the center plane of the roller's running surface, and can extend in particular parallel to this center plane. Thus, when the roller rotates about its vertical axis of rotation, a relative movement, so to speak, eccentric, occurs between the roller's support surface and the floor area. This arrangement can help create additional installation space for drive components laterally of the roller.

[0019] In another embodiment, the rotation and drive of the rollers of the roller arrangement, in particular all the rollers of the conveyor unit, about a vertical axis of rotation are coordinated by means of electronic control, in particular a control unit and / or power electronics. Thus, in contrast to previous drive concepts for conveyor units, the conveyor unit according to the present invention does not involve any mechanical coupling of the individual rollers. Rather, the rollers are coupled to one another solely via the control electronics in order to implement the desired travel motion.

[0020] It is also conceivable that the roller assembly of the conveyor unit is designed as identical modules, which are particularly interchangeable. Thus, the conveyor unit according to the present invention can have two identical roller assembly modules that do not differ from each other—except for possibly different controls or programming that are limited to the installation position. It is particularly conceivable that the modules are designed so that they can be removed from the conveyor unit and reinserted into it without tools or with relatively minimal use of tools. This design significantly reduces the storage costs of replacement parts and the effort required for repairs.

[0021] It is also possible that the line connecting the support surfaces of the rollers of the roller arrangement runs perpendicularly to the longitudinal axis of the frame structure, in particular, the rollers of the roller arrangement occupy mirror-symmetrical positions relative to the longitudinal axis of the frame structure.

[0022] The roller units, so to speak, placed side by side, reduce the necessary structural volume along the longitudinal axis of the conveying unit to a minimum. Thus, the support surface of the four-wheeled carriage of the conveying unit is rectangular in a top view.

[0023] In an alternative embodiment, the line connecting the support surfaces of the rollers of the roller arrangement runs obliquely relative to the longitudinal axis of the frame structure, in particular, the rollers of the roller arrangement occupy rotationally symmetrical positions relative to the longitudinal axis of the frame structure.

[0024] In this case, the support surface of the four-wheeled carriage of the conveyor unit will be a parallelogram in a vertical top view. This embodiment can help to reduce the necessary structural frame in width, ie transversely to the longitudinal axis of the conveyor unit.

[0025] The two embodiments described above allow the conveyor unit to be moved perpendicularly to its longitudinal axis. Even when the axes of rotation of the rollers are aligned parallel to the longitudinal axis of the conveyor unit, the support surfaces of the rollers are spaced apart on both sides from the central longitudinal axis of the conveyor unit, so that the entire conveyor unit can be supported by these support surfaces when traveling transversely to its longitudinal axis.

[0026] Since the dissipation of heat losses becomes increasingly important as the roller unit becomes more compact, it can be provided that the individual components or essential components of the roller unit are made of materials with relatively high thermal conductivity. The contact surfaces between these components can also be treated with materials or substances that conduct heat particularly well. This can improve the dissipation of heat to the immediate surroundings or, for example, into the frame structure.

[0027] According to one embodiment, the entire roller drive is arranged within a bearing (or bearing diameter) of the roller unit in the frame, in particular viewed in the vertical and / or horizontal direction.

[0028] It is also conceivable that the entire roller drive including the bearing device is located within the wheel diameter, especially when viewed in the vertical and / or horizontal direction. The running surface of the roller is therefore the component of the roller unit that is farthest from the roller axis of rotation.

[0029] According to another embodiment, the roller unit includes a support structure, in particular a one-piece support element, which is supported via a first rolling bearing, in particular directly on the frame structure, and the rollers and / or the ring gear of the transmission designed as a planetary transmission are supported via a second rolling bearing, in particular directly on the support structure. It is therefore possible to keep the force flow between the rollers and the frame structure as short as possible. As a result, forces and moments acting on the running surface of the rollers from the ground area can be directly introduced into the frame structure via the support structure, and vice versa. It is advantageous that the support structure extends as close as possible to the axis of rotation of the rollers, because this minimizes the moments and reduces material stresses. In this case, the support structure can carry, in particular directly carry, or even contact any components of the roller drive, such as an electric motor, a transmission, a brake, a control unit, a power electronics device, or any combination thereof.

[0030] Another aspect of the invention relates to a conveying device having a plurality of, in particular two, conveying units according to any of the embodiments described above.

[0031] The present invention will be described in detail below based on preferred embodiments and with reference to the accompanying drawings. The present invention may include all features described herein individually and in any meaningful combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings show:

[0033] Figure 1 A conveying device according to the present invention comprising two conveying units is shown;

[0034] Figure 2 A conveying unit according to the invention is shown with a schematically illustrated roller arrangement;

[0035] Figure 3 shows a cross section of a first embodiment of a roller unit according to the invention;

[0036] Figure 4 shows a cross section of another embodiment of a roller unit according to the invention;

[0037] Figure 5 A top view showing a first embodiment of a roller arrangement according to the present invention;

[0038] Figure 6 A second embodiment of the roller arrangement according to the invention is shown in a top view. DETAILED DESCRIPTION

[0039] Figure 1A two-part conveyor device is shown with two physically unconnected conveyor units 1. Such autonomous conveyor devices are known, for example, from DE 10 2007 046 868 A1 and DE 10 2019 001 125 A1. Figure 1 It is also shown how the conveyor unit can be moved completely under a load carrier (transport pallet / “Euro pallet”) in the lowered state in order to subsequently lift the load carrier for transport.

[0040] In addition to the supporting elements (not shown) for lifting the load carrier, Figure 2 The conveying unit 1 shown in FIG. 1 has a frame structure, which is Figure 2 In the example shown, the conveyor unit is divided into a front frame section 2A and a rear frame section 2B. Predefined structural volumes are provided in both the front frame section 2A and the rear frame section 2B to accommodate the roller assembly 5, each with two rollers. Therefore, all components of the roller assembly 5 must be accommodated within the available structural volume, which is again limited in height h and width b by the perimeter provided by the load carrier. The length l of the structural volume available solely for the roller assembly 5 can be varied, however, at the expense of other devices necessary for the function of the conveyor unit, such as a lifting device (not shown) for the load element, an energy storage device, or sensor systems necessary for autonomous operation. Because the roller assembly 5 in the example shown has two identical roller units 8, only half the structural volume is available for the latter.

[0041] The goal is to minimize the structural volume of the roller unit 8, as in Figure 3 As can be seen in FIG, all roller drives 7 necessary for driving the rollers 6 are arranged within the rotation path circle 9. Figure 3 The rotational path circle 9 shown in FIG. 1 is defined by the fact that the roller 6 is twisted 90° about its rotation axis D. All components of the roller drive 7 and the bearing 16 of the roller unit 8 relative to the frame structure 2 and about the vertical rotation axis D are arranged within the rotational path circle 9 .

[0042] from Figure 3 It is also apparent that the electric motor 11, the single-stage planetary gear 12, and the brake 13 are not only arranged coaxially with one another, but also relative to the axis of rotation R of the roller 6. The installation space available to the right of the brake 13 is occupied by the control unit 14 and the power electronics 15 for the electric motor 11. The running surface 10 of the roller 6 is directly connected to the ring gear (not shown) of the planetary gear 12 and forms the only component that extends beyond the upper and lower horizontal bearing planes defined by the rotary bearing 16.

[0043] Figure 4 The roller unit 8 according to the present invention is shown in another embodiment, including a support structure 17 designed as a one-piece element. The support element 17 is supported directly on the frame structure 2 via a rolling bearing 16 above and below the roller axis of rotation R, respectively, and is rotatable about the vertical axis of rotation D. The ring gear 18 of the planetary gear is supported directly on the support element 17 via two additional rolling bearings 19 above and below the roller axis of rotation R, and is rotatable about the horizontal axis of rotation R. The direct support of the support element 17 on the frame structure 2, on the one hand, and the direct support of the ring gear 18 or the roller 6 on the support element 17, on the other hand, allows for direct force transmission between the frame structure 2 and the roller 6, which improves the stability of the roller unit 8 according to the present invention. It can also be seen that the support element 17 extends vertically close to the vertical axis of rotation D, which also results in low moment loads on the roller unit 8. At the same time, space is created for the electric motor 11 and brake 12, which are directly supported by the support element 17. In the embodiment shown, the bearing 16 is not completely within the swivel circle 9, but is within the diameter of the roller 6 or the running surface 10, viewed both horizontally and vertically.

[0044] Figure 5 A first embodiment of a roller arrangement 5 according to the invention is shown, which has exactly two roller units 8 arranged “side by side”, as shown in FIG. Figure 3 The vertical rotation of the corresponding roller is achieved by two independent actuators, which are Figure 4 , schematically depicted as circles. The mechanical connection to the respective roller units 8 can be established, for example, via a belt drive (not shown), although any differently designed connection means, such as a chain drive or a gear drive, are conceivable. The rollers can be rotated independently of one another about their respective vertical axes of rotation via independent actuators, which can be designed as electric motors or servomotors. Because the steering movement of the individual rollers is performed by the actuators assigned to them, the steering of the conveyor unit according to the present invention is completely independent of the drive of the rollers by the electric motors 11 assigned to the respective rollers. Figure 5 It is also shown as an example for Figure 5The cable for the signal and energy supply of the roller unit 8 on the left is arranged in the middle. The cable runs between the interface on the frame side and the interface on the roller unit side and forms a cable loop between the interfaces around the vertical axis of rotation of the roller unit 8. Due to the "redundant" cable length between the interfaces, this allows a certain number of rotations of the roller unit 8 without causing any significant stress on the cable. Alternatively, Figure 5 The points shown at the ends of the cable loop in FIG. 8 can also be fixing points at which the cable is fixed in position relative to the frame structure or the roller unit 8 .

[0045] exist Figure 5 In the case of the arrangement shown in FIG, the connecting line V runs between the travel surfaces of the respective rollers 6 perpendicular to the longitudinal axis of the conveyor unit 1. The arrangement of two roller units 8 shown allows for a roller arrangement 5 that is very short in length l. The minimum width b is predetermined by the diameter of the rollers 6 or the diameter of the revolving path circle 9.

[0046] exist Figure 6 1 shows an embodiment that is more compact in width b. Here, the roller units 8 are arranged offset from one another so that their respective support surfaces can be connected via a connecting line V that runs obliquely to the longitudinal axis L of the conveyor unit 1 .

[0047] Although Figure 6 The embodiment shown is designed to be slightly longer in length l, but the diameter of the roller 6 or the revolving path circle 9, and thus the total structural volume available for the roller drive 7 and the support device 16 for a given width b, can be designed to be larger, which, for example, leads to a lower pressure per unit area on the supporting surface of the roller 6, while travel perpendicular to the longitudinal axis L of the conveying unit 1 is still possible.

Claims

1. A conveying unit (1) for conveying a material carrier, the conveying unit comprising: - an elongated frame structure (2), comprising a front frame section (2A) and a rear frame section (2B), each of the front frame section and the rear frame section comprising a roller arrangement (5) having at least two rollers (6) mounted so as to be rotatable relative to the frame structure (2) about a vertical axis of rotation (D); a support element capable of coming into contact with the load carrier, said support element being movable in the vertical direction between a raised position and a lowered position relative to the frame structure (2) by means of a lifting device; It is characterized in that Each of the roller arrangements (5) has at least one roller (6) which can be driven by means of a roller drive (7) designed as a wheel hub drive.

2. A conveying unit according to claim 1, wherein the roller drive (7) is arranged within a rotation trajectory circle (9) of the roller (6), and the rotation trajectory circle is swept by the travel surface (10) of the roller (6) when the roller (6) rotates around the vertical rotation axis (D).

3. A conveying unit according to any one of claims 1 or 2, wherein the roller drive (7) includes an electric motor (11), a transmission device (12) coupling the electric motor (11) and the roller (6), a brake (13) reacting to the driving torque of the electric motor (11), and a control unit (14) for controlling the electric motor (11), in particular, wherein the electric motor (11), the transmission device (12) and the brake (13) are arranged coaxially with the rotation axis (R) of the roller (6).

4. The conveyor unit according to claim 3, wherein the roller drive (7) further comprises power electronics (15) of the electric motor (11).

5. A conveying unit according to any one of claims 1 to 4, wherein a supporting device (16) for supporting a roller unit (8) relative to the frame structure (2) is arranged within a rotational trajectory circle (9) of the roller (6), the roller unit being formed by the roller (6) and the roller drive (7), the rotational trajectory circle being swept by the travel surface (10) of the roller (6) when the roller (6) rotates around the vertical rotation axis (D), in particular, wherein the roller unit (8) is supported relative to the frame structure (2) not only above the rotation axis (R) of the roller (6) but also below the rotation axis.

6. A conveying unit according to any one of claims 1 to 5, wherein the vertical axis of rotation (D) of the roller (6) is spaced apart from the center plane (M) of the roller (6), in particular from the center plane (M) of the roller travel surface (10), and in particular extends parallel to the center plane.

7. A conveying unit according to any one of claims 1 to 6, wherein the coordination of the rotation and drive of the rollers (6) of the roller device (5), in particular all the rollers (6) of the conveying unit (1) around the vertical axis of rotation (D) is carried out by means of an electronic control device, in particular by means of the control unit (14) and / or the power electronic device (15).

8. The conveyor unit according to claim 1, wherein the roller arrangement (5) of the conveyor unit (1) is designed as identically constructed modules, which are in particular replaceable with one another.

9. A conveying unit according to any one of claims 1 to 8, wherein the line (V) connecting the support surfaces (17) of the rollers (6) of the roller device (5) extends perpendicularly to the longitudinal axis (L) of the frame structure (2), in particular, wherein the rollers (6) of the roller device (5) occupy mirror-symmetrical positions relative to the longitudinal axis (L) of the frame structure (2).

10. A conveying unit according to any one of claims 1 to 8, wherein the line (V) connecting the support surfaces (17) of the rollers (6) of the roller device (5) extends obliquely relative to the longitudinal axis (L) of the frame structure (2), in particular, wherein the rollers (6) of the roller device (5) occupy a rotationally symmetrical position relative to the longitudinal axis (L) of the frame structure (2).

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