EP3848324B1 - Automatic guided vehicle - Google Patents

Description

The invention relates to a driverless transport vehicle, in particular for the transport of load carriers, which has a support frame and a chassis, wherein the chassis has a central axis with two non-steered wheels, a front axle with at least one steered wheel unit and a rear axle with at least one steered wheel unit, wherein the central axis and the front axle of the chassis are arranged on a first boom which is articulated to the support frame by means of a first articulation axis which has a horizontal pivot axis running in the transverse direction of the vehicle, and the rear axle of the chassis is arranged on a second boom which is articulated to the central axis or the first boom by means of a second articulation axis which has a horizontal pivot axis running in the transverse direction of the vehicle, wherein the second boom is connected to the support frame by means of a coupling element which is articulated to the second boom and to the support frame.

A generic driverless transport vehicle is from the FR 3 042 183 A1 known.

A driverless transport vehicle is from the DE 20 2013 004 209 U1 known.

The WO 2019/183220 A2 discloses an automated guided vehicle having a pivot joint between a front chassis unit and a rear chassis unit, both of which support a support structure that pivotally supports a payload enclosure.

To optimize and automate internal transport, driverless and thus autonomous transport vehicles, so-called AGVs (automated guided vehicles), are increasingly being used for internal transport. For this purpose, various forms of compact and flat self-driving transport vehicles designed as platform trucks are increasingly being used, which drive under a load carrier, for example a pallet or a trolley, and if necessary lift it slightly in order to move it horizontally and then These driverless transport vehicles control and navigate themselves automatically and are therefore autonomous.

Areas of application for such driverless transport vehicles in internal transport include, for example, the transport of pallets or trolleys from the storage location to a picking workstation and back or from a picking workstation to a production workstation.

Depending on the task, loads, load carriers and environment, there are different requirements and therefore different types, sizes and designs of such driverless transport vehicles.

In order to meet the requirements of such driverless transport vehicles in terms of limited maneuvering space, compact external dimensions and low manufacturing costs in the best possible compromise, driverless transport vehicles of this type with a chassis with three axles are known, of which the center axle is designed as a driven axle (drive axle) and the front axle and the rear axle are each designed as a non-driven axle with steerable wheels. If the drive wheels of the center axle can be operated and controlled independently of one another, a change in direction of travel can be forced and steering can take place by using different speeds and/or directions of rotation of the two drive wheels of the center axle, whereby the transport vehicle can rotate on the spot around its center point.

In the case of driverless transport vehicles of this type with a three-axle chassis, it must be ensured that the drive wheels are always sufficiently loaded in order to be able to safely transfer the drive torque to the roadway.

For this purpose, a chassis concept is known for a generic driverless transport vehicle with a three-axle chassis, in which the central axle, which is designed as the drive axle, is arranged a certain amount in the vertical direction below a connecting plane that connects the non-driven front axle and the non-driven rear axle. When driving over a level road, the drive axle always carries the largest part of the total load, and the other two axles (front axle/rear axle) only support one of the two axles, while the other axle is in the air. If the load changes, for example due to braking deceleration, the transport vehicle can tilt slightly about a transverse axis until the other axle comes into contact with the road and the support load is shifted from one axle to the other axle. However, the disadvantage of such a chassis concept is that the transport vehicle is only suitable for small uneven ground and small ramp angles of the road. In addition, the tilting of the vehicle about the transverse axis results in an inconsistency when the transport vehicle is driving. In addition, with such a chassis concept it is necessary to design the drive axle for the total load of the transport vehicle.

Furthermore, a chassis concept is known for a generic driverless transport vehicle with a three-axle chassis in which the load is balanced between the three axles, for example using spring elements. However, the disadvantage of such a chassis concept is that the chassis has a complex and elaborate structure and the load balancing between the three axles can be incomplete depending on the loading condition of the transport vehicle.

The present invention is based on the object of providing a driverless transport vehicle of the type mentioned at the beginning, in which the distribution of the load across the three axles is improved.

This object is achieved according to the invention in that the transport vehicle has a load-bearing platform for receiving a load carrier, wherein the load-bearing platform is arranged on the support frame and the support frame and the chassis are arranged vertically below the load-bearing platform, wherein the support frame has a longitudinal member running in the longitudinal direction of the vehicle and arranged centrally in the transverse direction of the vehicle, on which the first articulation axis is arranged and to which the coupling element is articulated.

The chassis of the transport vehicle according to the invention achieves a distribution of the mass forces and thus a load distribution on the three axles, which is always defined in every loading state of the transport vehicle, on roads with significant unevenness and when driving on ramps. The The transport vehicle provided with the chassis according to the invention can travel over larger uneven ground and larger ramp angles and the chassis has a simple structure.

In the transport vehicle according to the invention, the support frame is connected to the chassis on the one hand to the first boom via the first joint axis and on the other hand to the second boom, which can be pivoted about the second joint axis on the central axis or the first boom, via the coupling element, which is articulated to both the second boom and the support frame. The coupling element can be used to easily transmit forces between the support frame and the second boom and to easily achieve the length compensation required when pivoting the second boom about the second joint axis, which is arranged on the central axis which can be pivoted about the first joint axis or on the first boom which can be pivoted about the first joint axis.

According to the invention, the support frame has a longitudinal beam running in the longitudinal direction of the vehicle, on which the first articulation axis is arranged and to which the coupling element is connected in an articulated manner. This makes it possible to achieve a simple and cost-effective construction of the support frame. The longitudinal beam is preferably designed as a slim, bending- and torsion-resistant longitudinal beam, so that the longitudinal beam takes up little installation space and the transport vehicle has a compact structure with small dimensions.

According to the invention, the longitudinal member is arranged centrally in the transverse direction of the vehicle. The longitudinal member can thus utilize the installation space between the two wheel carriers of the two wheels of the central axle and can be arranged between the two wheel carriers of the wheels of the central axle, whereby the transport vehicle has compact vertical dimensions and is thus designed as a flat-built transport vehicle that can drive under a load carrier to be transported, for example a pallet or a trolley.

According to an advantageous embodiment of the invention, the first articulation axis is arranged in the vehicle longitudinal direction between the center axis and the front axle.

Particular advantages arise if, according to one embodiment of the invention, the second joint axis is arranged coaxially to a rotation axis of the wheels of the central axis. The second boom is thus rotatably mounted or pivotable about the rotation axis of the wheels of the central axis, for example on the central axis. This enables a simple construction. Alternatively, the second joint axis can be arranged parallel to the rotation axis of the wheels of the central axis and arranged near the rotation axis of the wheels of the central axis, for example on the first boom or on the central axis.

According to an advantageous embodiment of the invention, the coupling element is arranged in the vehicle longitudinal direction between the center axle and the rear axle.

Particular advantages arise if, according to an advantageous development of the invention, the first joint axis comprises two joint connections that are arranged at a distance from one another in the transverse direction of the vehicle. With two such joint connections arranged coaxially to the first joint axis, which are arranged at a distance from one another in the transverse direction of the vehicle, not only forces can be transmitted between the support frame and the first boom at the first joint axis, but torques can also be transmitted from the support frame to the first boom around the longitudinal axis of the transport vehicle.

With regard to a simple structure of the first joint axis, particular advantages arise if the joint connections are each designed as a bolt connection. The two bolt connections that form the first joint axis can have two separate bolts or one common bolt.

According to a further development of the invention, the bolt connections between the first boom of the chassis and the support frame can be designed as conventional force measuring bolts, so that a relatively accurate measurement of the loading state of the transport vehicle with regard to weight force and center of gravity of the load carried is possible.

According to an advantageous development of the invention, the wheels of the central axle are each mounted in or on a wheel carrier so as to be rotatable about the axis of rotation, wherein the Wheel carriers are attached to the first boom. The wheel carriers are thus firmly connected to the first boom, which allows for a simple construction of the chassis.

A simple and cost-effective design for the second joint axis can be achieved if, according to an advantageous embodiment of the invention, the second joint axis comprises at least one bearing ring arranged on the second arm, which is rotatably mounted on a circular ring surface of the wheel carrier. The circular ring surface can be produced in a cost-effective manner by means of a suitably machined surface on the outer circumference of the wheel carrier, on which the second arm is rotatably mounted with the bearing ring.

Advantageously, a plain bearing is arranged between the circular ring surface of the wheel carrier and the bearing ring. The plain bearing can be used to achieve low frictional forces on the second joint axis.

According to an advantageous embodiment of the invention, the coupling element has at least one tension-compression rod which is articulated to the second boom by means of a third joint axis which has a horizontal pivot axis running in the transverse direction of the vehicle, and which is articulated to the support frame by means of a fourth joint axis which has a horizontal pivot axis running in the transverse direction of the vehicle. The support frame is thus connected to the pivotable second boom via the coupling element which is articulated to the second boom and to the support frame by means of two horizontal joint axes, so that the coupling element can be formed by a simply constructed tension-compression rod which transmits corresponding tensile or compressive forces in only one direction, namely the longitudinal direction of the coupling element.

With regard to a simple structure, advantages arise when the third joint axis and the fourth joint axis are each designed as a joint connection, which is designed as a bolt connection. According to a further development of the invention, one or both bolt connections between the coupling element and the support frame can be designed as conventional force measuring bolts, so that a relatively accurate measurement of the loading state of the transport vehicle in terms of weight and centre of gravity of the load being carried.

According to an advantageous embodiment of the invention, the longitudinal member is widened in the area of the front axle and in the area of the rear axle. This makes it easy to safely take up the load of the load carrier from the support frame.

According to an advantageous development of the invention, the support frame is provided with support elements in the area of the four outer corners of the vehicle, which are intended to support the vehicle on a road surface. The additional support elements can be used to improve the tipping stability of the transport vehicle in a simple manner. The support elements arranged and fastened to the support frame are preferably arranged on the support frame in such a way that the support elements are arranged as close as possible to the four outer corners of the transport vehicle and have a small vertical distance from the road, so that the support elements are located as close to the road as is possible without disrupting normal driving. If the transport vehicle tips over during operation, for example as a result of an error, one of the support elements comes into contact with the road and thereby increases the support base of the transport vehicle, so that further tipping of the transport vehicle is prevented.

According to one embodiment of the invention, the load-bearing platform is firmly attached to the support frame. A load placed on the load-bearing platform is thus received via a load-bearing platform rigidly attached to the support frame.

According to an alternative embodiment of the invention, the load-bearing platform is arranged on the support frame so that it can be raised and lowered in the vertical direction by means of a lifting device. A load placed on the load-bearing platform is thus picked up by a load-bearing platform arranged on the support frame so that it can be raised and lowered. For this purpose, a corresponding lifting device can be provided between the support frame and the load-bearing platform, with which the load-bearing platform and the load can be raised or lowered.

According to an advantageous embodiment of the invention, the wheel unit of the front axle and/or the rear axle is each designed as a non-driven and passive steered wheel unit. The corresponding wheel unit on the front axle or rear axle can advantageously be passively steered by means of a caster.

According to an alternative embodiment of the invention, the wheel unit of the front axle and/or the rear axle is each designed as a non-driven and actively steered wheel unit. The corresponding wheel unit on the front axle or on the rear axle can advantageously be actively steered by a corresponding steering drive.

According to an alternative embodiment of the invention, the wheel unit of the front axle and/or the rear axle is each designed as a driven and actively steered wheel unit. The corresponding wheel unit on the front axle or on the rear axle can advantageously be driven by a corresponding drive unit, for example an electric drive motor, and actively steered by a corresponding steering drive. In conjunction with a driven central axle, the drive forces can be distributed to all wheels. Alternatively, the central axle can be provided with non-driven and non-steered wheels, which enables a cost-effective construction of the central axle.

According to an advantageous embodiment of the invention, the wheel unit of the front axle and/or the rear axle is designed as a double wheel with two wheels arranged at a distance from each other. If the wheel unit is passively steered, the torques for steering the wheel unit can be reduced with such a double wheel. In addition, a gap is created between the two wheels of the double wheel, which can be used for the installation of further components, for example sensors, actuators or connecting elements.

According to an advantageous embodiment of the invention, the front axle and/or the rear axle has a wheel unit arranged centrally in the transverse direction of the transport vehicle.

Alternatively, the front axle and/or the rear axle can be designed as a swing axle with two wheel units, in particular with two passively steered wheel units. According to an advantageous embodiment of the invention, the wheels of the central axle are designed as drive wheels, each of which is driven by a drive unit, in particular an electric drive unit, with the wheel carriers being designed as housings for the drive units. The speed of the two drive wheels can preferably be controlled or regulated independently of one another. A change in direction of travel can thus be forced by different speeds and/or directions of rotation of the two drive wheels of the central axle, thus enabling steering. This also makes it possible to rotate the transport vehicle on the spot around its center point.

If the wheel unit of the front axle and/or the rear axle is designed as a driven and actively steered wheel unit, according to an advantageous embodiment of the invention the wheels of the central axle can be designed as non-driven wheels.

The transport vehicle according to the invention has a number of advantages.

The chassis and the supporting frame are space-saving and cost-effective and enable a space-saving and cost-effective design of the transport vehicle.

A statically determined load distribution is achieved by the articulated connection of the first boom, which is provided with the central axis and the front axle, to the support frame and the articulated connection of the second boom, which is provided with the rear axle, to the central axis or the first boom, as well as the connection of the second boom to the support frame by means of the coupling element. The bending and torsion-resistant support frame takes the payload as well as cladding parts and components of the driverless transport vehicle, for example a battery, an electric lifting motor of a lifting device of the load-carrying platform, electronic controls for controlling the electric drive units of the two drive wheels and for controlling the lifting motor, as well as sensors, for example sensors for monitoring the environment and/or for navigating the driverless transport vehicle. The support frame is connected to the two booms and thus to the vehicle via the articulated axis and the articulated coupling element. the chassis is connected in such a way that the reaction forces to the weight force as well as to the drive and braking forces are distributed in a favourable manner across the three axles of the chassis. By choosing the distances between the joint axes and the axles, an optimum load distribution can be constructed on the chassis, which results in high tipping stability in the direction of travel, high tipping stability in the transverse direction of the vehicle and thus transverse to the direction of travel, favourable loads on the three axles and wheels, favourable ground pressure and sufficient traction on the drive wheels for driving and braking.

Overall, a compact and maneuverable driverless transport vehicle with a three-axle chassis is achieved, in which the inertia forces on the three axles of the chassis are always defined in every loading condition, when driving on a road with significant road unevenness and when driving on ramps.

The constantly defined load distribution on the three axles of the chassis achieved with the chassis according to the invention makes it possible to dimension the wheels, axles, brakes and wheel bearings precisely to the loads without having to take into account large allowances for uncertainties in the load distribution, so that a space-saving and cost-effective design of the chassis can be achieved.

An optimal compromise between manufacturing costs, wear, road load, traction and tipping safety can be determined and implemented in the design of the chassis. If the chassis is designed accordingly, the maximum braking deceleration can be limited even if the parking brakes on the drive wheels are applied in an emergency. This would otherwise be significantly higher than the design value for light to medium loads and could lead to instability of the load being carried or the transport vehicle.

Figur 1

ein erfindungsgemäßes fahrerloses Transportfahrzeug in einer perspektivischen Darstellung,

Figur 2

das Transportfahrzeug der Figur 1 mit angehobener Lastaufnahmeplattform,

Figur 3

das Transportfahrzeug der Figuren 1 und 2 ohne Verkleidungsbauteile,

Figur 4

eine perspektivische Darstellung des Tragrahmens und des Fahrwerks des erfindungsgemäßen Transportfahrzeugs,

Figur 5

eine weitere perspektivische Darstellung des Tragrahmens und des Fahrwerks des erfindungsgemäßen Transportfahrzeugs,

Figur 6

eine Explosionsdarstellung des Tragrahmens und des Fahrwerks des erfindungsgemäßen Transportfahrzeugs,

Figur 7

eine Darstellung des Tragrahmens und des Fahrwerks des erfindungsgemäßen Transportfahrzeugs auf einer ebenen Fahrbahn,

Figur 8

eine Darstellung des Tragrahmens und des Fahrwerks des erfindungsgemäßen Transportfahrzeugs auf einer eine Senke aufweisenden Fahrbahn und

Figur 9

eine Darstellung des Tragrahmens und des Fahrwerks des erfindungsgemäßen Transportfahrzeugs auf einer eine Kuppe aufweisenden Fahrbahn.

Further advantages and details of the invention are explained in more detail with reference to the embodiment shown in the schematic figures.

Figure 1

a driverless transport vehicle according to the invention in a perspective view,

Figure 2

the transport vehicle of the Figure 1 with raised load-bearing platform,

Figure 3

the transport vehicle of the Figures 1 and 2 without cladding components,

Figure 4

a perspective view of the supporting frame and the chassis of the transport vehicle according to the invention,

Figure 5

a further perspective view of the supporting frame and the chassis of the transport vehicle according to the invention,

Figure 6

an exploded view of the supporting frame and the chassis of the transport vehicle according to the invention,

Figure 7

a representation of the supporting frame and the chassis of the transport vehicle according to the invention on a flat roadway,

Figure 8

a representation of the supporting frame and the chassis of the transport vehicle according to the invention on a roadway with a depression and

Figure 9

a representation of the supporting frame and the chassis of the transport vehicle according to the invention on a roadway having a hill.

In the Figures 1 to 3 a driverless, in particular autonomous, transport vehicle 1 according to the invention is shown. The transport vehicle 1 is designed for the horizontal transport of a load carrier (not shown in detail), for example a pallet or a trolley.

The transport vehicle 1 has a mobile undercarriage 2, which is provided with a supporting frame 3 and a chassis 4, and a load-bearing platform 5 arranged above the undercarriage 2 for receiving the load carrier.

The undercarriage 2 has cladding components 6 arranged on the support frame 3, under which the support frame 3 and the chassis 4 are arranged. The Figures 1 and 2 show the transport vehicle 1 with the cladding components 6. In the Figure 3 the cladding components 6 are not shown.

In the embodiment shown, the load-bearing platform 5 is arranged on the support frame 3 so that it can be raised and lowered in the vertical direction. For this purpose, a Figures 2 and 3 shown lifting device 7 is provided, which is connected to the load-bearing platform 5.

The support frame 3 and the chassis 4 are arranged vertically below the load-bearing platform 5. The transport vehicle 1 is thus designed as a flat and compact self-propelled transport vehicle that allows the load carrier to be driven under and the load carrier to be lifted with the load-bearing platform 5 in order to transport the load carrier horizontally and then set it down again. The navigation and control of the transport vehicle 1 takes place automatically or autonomously; alternatively, remote-controlled operation of the transport vehicle 1 is also possible.

The chassis 4 of the transport vehicle 1 according to the invention consists of three axles and is formed by a central axle 10 with two non-steered wheels 10a, 10b, a front axle 11 with at least one steered wheel unit 11a and a rear axle 12 with at least one steered wheel unit 12a.

The structure of the supporting frame 3 and the chassis 4 is described below using the Figures 4 to 6 described in more detail.

The central axis 10 and the front axle 11 of the chassis 4 are arranged on a first boom 15, which is connected in an articulated manner to the support frame 3 by means of a first joint axis G1. The first joint axis G1 has a horizontal pivot axis S1 running in the transverse direction Q of the vehicle. The first boom 15 is designed as a bending and torsion-resistant boom. The first boom 15 extends forward in the longitudinal direction L of the vehicle.

The rear axle 12 of the chassis 4 is arranged on a second boom 16. The second boom 16 is articulated to the central axis 10 or the first boom 15 by means of a second articulated axis G2. The second articulated axis G2 has a horizontal pivot axis S2 running in the transverse direction Q of the vehicle. The second boom 16 is connected to the support frame 3 by means of a coupling element 20. The coupling element 20 is articulated to the second boom 16 and to the support frame 3. The second boom 16 is designed as a bending and torsion-resistant boom. The second boom 16 extends rearward in the longitudinal direction L of the vehicle.

The first joint axis G1 is - as shown in the Figures 4 to 6 can be seen - arranged in the vehicle longitudinal direction L between the central axle 10 and the front axle 11.

In the illustrated embodiment, as in the Figures 4 to 6 can be seen - the second joint axis G2 is arranged coaxially to a rotation axis D of the two wheels 10a, 10b of the central axis 11, so that the second boom 6 is arranged pivotably about the rotation axis D of the central axis 10.

The coupling element 20 is - as in the Figures 4 to 6 can be seen - arranged in the vehicle longitudinal direction L between the central axle 10 and the rear axle 12.

The support frame 3 is thus connected to the chassis 4, firstly to the first, fixed boom 15 by the first articulated connection G1 and secondly to the second, pivotable boom 16 by the coupling element 20.

The two wheels 10a, 10b of the central axle 10 are in the illustrated embodiment - as in the Figures 4 to 6 can be seen in more detail - each mounted in a wheel carrier 30a, 30b so as to be rotatable about the axis of rotation D. The wheel carriers 30a, 30b are rigidly and thus firmly attached to the first arm 15. For this purpose, a first fastening flange 31a is formed on the first arm 15, to which the first wheel carrier 30a can be fastened, for example by means of fastening screws 32. For this purpose, a second fastening flange 31b is also formed on the first arm 15, to which the second wheel carrier 30b can be fastened, for example by means of fastening screws not shown in detail. In the illustrated embodiment, the second fastening flange 31b is formed integrally on the first boom 15. In the illustrated embodiment, the first fastening flange 31a is formed on a flange plate 33 which is fastened to the boom 15, for example by means of fastening screws 34.

In the embodiment shown, the second joint axis G2 is formed by two bearing rings 40a, 40b attached to the second boom 16. The bearing ring 40a is rotatably mounted on a circular ring surface 41a of the wheel carrier 30a. The bearing ring 40b is correspondingly rotatably mounted on a circular ring surface 41b of the wheel carrier 30b. The circular ring surfaces 41a, 41b are arranged concentrically to the axis of rotation D of the wheels 10a, 10b. The second boom 16 is thus mounted so that it can rotate or pivot about the central axis 10 of the chassis 4.

A plain bearing (not shown in detail), for example a plastic plain bearing, can be arranged between the circular ring surface 41a, 41b of the wheel carrier 30a, 30b and the corresponding bearing ring 40a, 40b.

In the exemplary embodiment shown, the first joint axis G1 comprises two joint connections G1a, G1b, which are arranged at a distance from one another in the transverse direction Q of the vehicle. The two joint connections G1a, G1b are each designed as a bolt connection. The joint connection G1a is formed by a receiving bore 25a in a side plate 26a of the first boom 15 and a receiving bore in a flange plate 27a of the support frame 3, in which a bolt 28 of the bolt connection is arranged. The receiving bore 25a of the bolt 28 formed in the side plate 26a of the boom 15 is formed in the exemplary embodiment shown by a semicircular recess in the side plate 26a and a half-shell 29a fastened to the side plate 26a, which is provided with a second semicircular recess. The articulated connection G1b is formed by a receiving bore 25b in a side plate 26b of the first boom 15 and a receiving bore in a flange plate 27b of the support frame 3, in which the bolt 28 of the bolt connection is arranged. The receiving bore 25b of the bolt 28 formed in the side plate 26b of the boom 15 is formed in the embodiment shown by a semicircular recess in the side plate 26b and a half-shell 29b attached to the side plate 26b. which is provided with a second semicircular recess. In the illustrated embodiment, a common bolt 28 is provided for both joint connections G1a, G1b.

The bolt 28 can be designed as a force measuring bolt.

The two articulated connections G1a, G1b, which form the first articulated axis G1 and are arranged at a distance from one another in the transverse direction Q of the vehicle, make it possible to transmit forces between the supporting frame 3 and the first boom 15 and to transmit torques about the longitudinal axis L of the vehicle.

The coupling element 20 has at least one tension-compression rod 50 and is provided with two joints. For this purpose, the coupling element 20 is connected in an articulated manner to the second boom 16 by means of a third articulated axis G3, which has a horizontal pivot axis S3 running in the transverse direction Q of the vehicle, and to the support frame 3 by means of a fourth articulated axis G4, which has a horizontal pivot axis S4 running in the transverse direction Q of the vehicle.

The third joint axis G3 and the fourth joint axis G4 are each designed as a joint connection, which is designed as a bolt connection. The joint connection forming the third joint axis G3 is formed by a receiving bore 51 of the second boom 16 and a receiving bore 52 of the tension-compression rod 50, in which a bolt 53 of the bolt connection is arranged. The joint connection forming the fourth joint axis G4 is formed by a receiving bore 55 of the support frame 3 and a receiving bore 56 of the tension-compression rod 50, in which a bolt 57 of the bolt connection is arranged.

The bolt 53 and/or the bolt 57 can be designed as a force measuring bolt.

The coupling element 20, which is designed as a tension-compression rod 50 and is coupled to the second boom 16 and to the support frame 3 by the two joint axes G3, G4, thus only transmits forces in one direction between the support frame 3 and the second boom 16, namely in the longitudinal direction of the coupling element 20.

In the exemplary embodiment shown, the support frame 3 has a longitudinal member 3a running in the vehicle's longitudinal direction L, on which the first articulation axis G1 is arranged and to which the coupling element 20 is articulatedly connected at the fourth articulation axis G4. The longitudinal member 3a is designed as a bending and torsion-resistant longitudinal member.

The longitudinal beam 3a of the support frame 3 is arranged centrally in the vehicle transverse direction Q. Between the two fastening flanges 31a, 31b, which are arranged on the first boom 15 and to which the wheel carriers 30a, 30b are fastened, a gap is formed in which the longitudinal beam 3 is arranged or can be inserted. The longitudinal beam 3a thus uses the space between the two wheel carriers 30a, 30b. This enables a flat design of the transport vehicle 1.

The longitudinal member 3a and thus the support frame 3 is widened in the area of the front axle 12 and in the area of the rear axle 13a and is provided with the lifting device 7 in the widened end areas, so that the load taken up by the load-bearing platform 5 is taken up by the widened end areas of the support frame 3.

In the illustrated embodiment, the support frame 3 is provided in the area of the four outer corners of the transport vehicle 1 with a column-like support element 60, 61, 62, 63, which have a small distance from the roadway during normal driving operation and come into contact with the roadway when the transport vehicle 1 is tipped over.

In the embodiment shown, the two wheels 10a, 10b of the central axle 10 are each designed as a drive wheel, each of which is driven by a drive unit, for example an electric drive unit. The central axle 10 is thus designed as a drive axle with two drive units, which are firmly connected to the first boom 15. The drive unit can be formed by an electric drive motor, which drives the corresponding wheel 10a, 10b directly or with the interposition of a gear. The two drive units can be controlled or regulated independently of one another in terms of speed and direction of rotation, so that different speeds on the two wheels 10a, 10b and The transport vehicle 1 can be steered and can turn on the spot by means of the wheels 10a, 10b in different directions of rotation. The wheel carriers 30a, 30b are designed as housings for the drive units.

In the illustrated embodiment, the wheel unit 11a of the front axle 11 is designed as a non-driven and passively steered wheel unit 11a. The wheel unit 11a is mounted on the front end of the first boom 15 so as to be rotatable about a vertical axis V1 by means of a corresponding bearing. The wheel unit 11a is provided with a caster and is passively steered by the caster.

The wheel unit 11a of the front axle 11 is arranged centrally in the vehicle transverse direction Q.

The wheel unit 11a of the front axle 11 is designed as a double wheel with two wheels 70, 71 arranged laterally spaced from each other.

For this purpose, the two wheels 70, 71 are mounted so as to be rotatable about a common horizontal axis of rotation D10 in a turntable 72, which is mounted so as to be rotatable about the vertical axis V1 in the first boom 15. The horizontal axis of rotation D10 is spaced apart from the vertical axis V1 in the horizontal direction, with this distance forming the caster for passive steering of the wheel unit 11a.

In the illustrated embodiment, the wheel unit 12a of the rear axle 12 is designed as a non-driven and passively steered wheel unit 12a. The wheel unit 12a is mounted at the rear end of the second boom 16 so as to be rotatable about a vertical axis V2 by means of a corresponding bearing. The wheel unit 12a is provided with a caster and is passively steered by the caster.

The wheel unit 12a of the rear axle 12 is arranged centrally in the transverse direction Q of the vehicle.

The wheel unit 12a of the rear axle 12 is designed as a double wheel with two wheels 75, 76 arranged laterally spaced from each other.

For this purpose, the two wheels 75, 76 are mounted so as to be rotatable about a common horizontal axis of rotation D11 in a turntable 77, which is mounted so as to be rotatable about the vertical axis V2 in the second boom 16. The horizontal axis of rotation D11 is spaced apart from the vertical axis V2 in the horizontal direction, with this distance forming the caster for passive steering of the wheel unit 12a.

In the embodiment shown, the central axis 10 of the chassis 4 is thus designed as a driven drive axle, which consists of two drive units that are firmly connected to the bending and torsion-resistant first boom 15. The first boom 15 carries the non-driven front axle 11 of the chassis 4, which includes the passively steered wheel unit 11a. The bending and torsion-resistant second boom 16 carries the non-driven rear axle 12 of the chassis 4, which includes the passively steered wheel unit 12a. The second boom 16 can be rotated or pivoted about the axis of rotation D of the wheels 10a, 10b of the central axis 10 (articulated axis G2). This articulated axis G2 can be produced simply and inexpensively by means of the bearing rings 40a, 40b arranged on the second boom 16, which run on the circular ring surfaces 41a, 41b produced on the housings of the drive units 30a, 30b. The support frame 3 is connected to the chassis 4, firstly to the first, fixed boom 15 by the first articulated connection G1, which is formed by the two articulated connections G1a, G1b arranged at a distance from one another in the transverse direction Q of the vehicle, and secondly to the second boom 16, which can be pivoted about the central axis 10, by the coupling element 20 having the two joints (articulated axes G3, G4).

The cladding components 6 are attached to the support frame 3. Furthermore, other components of the driverless transport vehicle 1, not shown in detail, are attached to the support frame 3, for example a battery, an electric lifting motor of the lifting device 7, electronic controls for controlling the electric drive units of the two wheels 10a, 10b and for controlling the lifting motor, as well as sensors, for example sensors for monitoring the environment and/or for navigating the driverless transport vehicle.

In the Figure 7 the supporting frame 3 and the chassis 4 of the transport vehicle 1 according to the invention are shown on a flat roadway FB. The wheels 10a, 10b the central axle 10, the wheel unit 11a of the front axle 11 and the wheel unit 12a of the rear axle 12 are in contact with the ground.

The Figure 8 shows the support frame 3 and the chassis 4 of the transport vehicle 1 according to the invention when driving through a depression in the roadway FB, with the central axis 10 located in the depression of the roadway FB. The wheels 10a, 10b of the central axis 10, the wheel unit 11a of the front axle 11 and the wheel unit 12a of the rear axle 12 are in contact with the ground. Compared to the Figure 7 the first boom 15 is pivoted clockwise about the first joint axis G1, so that the central axis 10 is pivoted downwards and the front axle 11 is pivoted upwards. Due to the pivoting movement of the central axis 10 downwards, the second boom 16, which is coupled to the central axis 10 about the second joint axis G2 and is articulated to the support frame 3 with the coupling element 20 having two joints (joint axes G3, G4), is pivoted counterclockwise, so that the rear axle 12 is pivoted upwards. The coupling element 20 enables the necessary length compensation when pivoting the second boom 16.

The Figure 9 shows the supporting frame 3 and the chassis 4 of the transport vehicle 1 according to the invention when driving over a crest on the roadway FB, with the central axis 10 located on the crest of the roadway FB. The wheels 10a, 10b of the central axis 10, the wheel unit 11a of the front axle 11 and the wheel unit 12a of the rear axle 12 are in contact with the ground. Compared to the Figure 7 the first boom 15 is pivoted anti-clockwise about the first joint axis G1, so that the central axis 10 is pivoted upwards and the front axle 11 is pivoted downwards. Due to the pivoting movement of the central axis 10 upwards, the second boom 16, which is coupled to the central axis 10 about the second joint axis G2 and is articulated to the support frame 3 with the coupling element 20 having two joints (joint axes G3, G4), is pivoted clockwise, so that the rear axle 12 is pivoted downwards. The coupling element 20 enables the necessary length compensation when pivoting the second boom 16.

Claims (23)

1. Driverless transport vehicle (1), in particular for transporting load carriers, which has a load-bearing frame (3) and a running gear (4), wherein the running gear (4) has a centre axle (10) with two unsteered wheels (10a, 10b), a front axle (11) with at least one steered wheel unit (11a), and a rear axle (12) with at least one steered wheel unit (12a), wherein the centre axle (10) and the front axle (11) of the running gear (4) are arranged on a first bracket (15) which is connected in an articulated manner to the load-bearing frame (3) by means of a first pivot pin (G1) which has a horizontal swivel pin (S1) which runs in the vehicle transverse direction (Q), and the rear axle (12) of the running gear (4) is arranged on a second bracket (16) which is connected in an articulated manner to the centre axle (10) or the first bracket (15) by means of a second pivot pin (G2) which has a horizontal swivel pin (S2) which runs in the vehicle transverse direction (Q), wherein the second bracket (16) is connected to the load-bearing frame (3) by means of a coupling element (20) which is connected in an articulated manner to the second bracket (16) and to the load-bearing frame (3), characterized in that the transport vehicle (1) has a load-receiving platform (5) for receiving a load carrier, wherein the load-receiving platform (5) is arranged on the load-bearing frame (3), and the load-bearing frame (3) and the running gear (4) are arranged in the vertical direction below the load-receiving platform (5), wherein the load-bearing frame (3) has a longitudinal carrier (3a) which runs in the vehicle longitudinal direction (L), is arranged centrally in the vehicle transverse direction (Q), on which the first pivot pin (G1) is arranged, and to which the coupling element (20) is connected in an articulated manner.
2. Driverless transport vehicle according to Claim 1, characterized in that the first pivot pin (G1) is arranged in the vehicle longitudinal direction (L) between the centre axle (10) and the front axle (11).
3. Driverless transport vehicle according to Claim 1 or 2, characterized in that the second pivot pin (G2) is arranged coaxially with respect to a rotational axis (D) of the wheels (10a, 10b) of the centre axle (10).
4. Driverless transport vehicle according to one of Claims 1 to 3, characterized in that the coupling element (20) is arranged in the vehicle longitudinal direction (L) between the centre axle (10) and the rear axle (12).
5. Driverless transport vehicle according to one of Claims 1 to 4, characterized in that the first pivot pin (G1) comprises two articulated connections (G1a, G1b) which are arranged spaced apart from one another in the vehicle transverse direction (Q).
6. Driverless transport vehicle according to Claim 5, characterized in that the articulated connections (G1a, G1b) are each configured as a bolt connection.
7. Driverless transport vehicle according to one of Claims 1 to 6, characterized in that the wheels (10a, 10b) of the centre axle (10) are each mounted in or on a wheel support (30a, 30b) such that they can be rotated about the rotational axis (D), wherein the wheel supports (30a, 30b) are fastened to the first bracket (15).
8. Driverless transport vehicle according to Claim 7, characterized in that the second pivot pin (G2) comprises at least one bearing ring (40a; 40b) which is arranged on the second bracket (16) and is mounted rotatably on a circular ring surface (41a; 41b) of the wheel support (30a; 30b).
9. Driverless transport vehicle according to Claim 8, characterized in that a plain bearing is arranged between the circular ring surface (41a; 41b) of the wheel support (30a; 30b) and the bearing ring (40a; 40b).
10. Driverless transport vehicle according to one of Claims 1 to 9, characterized in that the coupling element (20) has at least one push-pull rod (50) which is connected in an articulated manner to the second bracket (16) by means of a third joint pin (G3) which has a horizontal swivel pin (S3) which runs in the vehicle transverse direction (Q), and which push-pull rod is connected in an articulated manner to the load-bearing frame (3) by means of a fourth joint pin (G4) which has a horizontal swivel pin (S4) which runs in the vehicle transverse direction (Q).
11. Driverless transport vehicle according to Claim 10, characterized in that the third joint pin (G3) and the fourth joint pin (G4) are each configured as an articulated connection which is configured as a bolt connection.
12. Driverless transport vehicle according to one of Claims 1 to 11, characterized in that the longitudinal carrier (3a) is widened in the region of the front axle (11) and in the region of the rear axle (12).
13. Driverless transport vehicle according to one of Claims 1 to 12, characterized in that, in the region of the four outer corners of the transport vehicle (1), the load-bearing frame (3) is provided with supporting elements (60, 61, 62, 63) which are provided to support the transport vehicle (1) on a roadway surface (FB).
14. Driverless transport vehicle according to one of Claims 1 to 13, characterized in that the load-receiving platform (5) is fastened fixedly to the load-bearing frame (3).
15. Driverless transport vehicle according to one of Claims 1 to 13, characterized in that the load-receiving platform (5) is arranged on the load-bearing frame (3) such that it can be lifted and lowered in the vertical direction by means of a lifting device (7).
16. Driverless transport vehicle according to one of Claims 1 to 15, characterized in that the wheel unit (11a, 12a) of the front axle (11) and/or the rear axle (12) is configured in each case as a non-driven and passively steered wheel unit (11a, 12a).
17. Driverless transport vehicle according to one of Claims 1 to 15, characterized in that the wheel unit (11a, 12a) of the front axle (11) and/or the rear axle (12) is configured in each case as a non-driven and actively steered wheel unit (11a, 12a).
18. Driverless transport vehicle according to one of Claims 1 to 15, characterized in that the wheel unit (11a, 12a) of the front axle (11) and/or the rear axle (12) is configured in each case driven and actively steered wheel unit (11a, 12a).
19. Driverless transport vehicle according to one of Claims 1 to 18, characterized in that the wheel unit (11a; 12a) is configured in each case as a twinned wheel with two wheels (70, 71; 75, 76) which are arranged spaced apart.
20. Driverless transport vehicle according to one of Claims 1 to 19, characterized in that the front axle (11) and/or the rear axle (12) have/has a wheel unit (11a, 12a) which is arranged centrally in the vehicle transverse direction (Q).
21. Driverless transport vehicle according to one of Claims 1 to 19, characterized in that the front axle (11) and/or the rear axle (12) are/is configured as a swing axle with two wheel units.
22. Driverless transport vehicle according to one of Claims 1 to 21, characterized in that the wheels (10a, 10b) of the centre axle (10) are configured as drive wheels which are each driven by a drive unit, in particular an electric drive unit, wherein the wheel supports (30a, 30b) are configured as housings of the drive units.
23. Driverless transport vehicle according to one of Claims 1 to 21, characterized in that the wheels (10a, 10b) of the centre axle (10) are configured as non-driven wheels.

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