EP3845482A1 - Driverless transport vehicle with a load support platform which can be raised and lowered by a spindle drive - Google Patents

Abstract

The invention relates to an automated guided vehicle (1), in particular for the transport of load carriers (LT), which has a mobile underframe (2) and a load-bearing platform (5) for receiving a load carrier (LT), the underframe (2) in a vertical position Direction is arranged below the load-bearing platform (5) and the load-bearing platform (5) can be raised and lowered in the vertical direction by means of a lifting device (7) on a vehicle frame of the undercarriage (2), the lifting device (7) as a threaded spindle drive (50) at least one vertically arranged threaded spindle drive (50a; 50b; 50c) is formed. At least one vertically arranged linear guide device (80) is arranged between the vehicle frame (3) and the load-bearing platform (5). The linear guide device (80) is designed in such a way that forces from the linear guide device (80) in a plane lying perpendicular to a vertically arranged spindle axis (SA) of the threaded spindle drive (50a; 50b; 50c) from the load-bearing platform (5) to the vehicle frame (3 ) be transmitted.

Description

The invention relates to a driverless transport vehicle, in particular for the transport of load carriers, which has a mobile underframe and a load-bearing platform for receiving a load carrier, the underframe being arranged in the vertical direction below the load-bearing platform and the load-bearing platform by means of a lifting device on a vehicle frame of the undercarriage can be raised and lowered in the vertical direction, the lifting device being designed as a threaded spindle drive with at least one vertically arranged threaded spindle drive.

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-propelled transport vehicles designed as platform vehicles are increasingly being used, which drive under a load carrier, for example a pallet or a roller cart or a shelf with parking feet, and lift it slightly in order to move it horizontally and thus transport it and stop again. These driverless transport vehicles control and navigate themselves automatically and thus autonomously.

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

Various designs of lifting devices are known for raising and lowering the load-bearing platform, for example scissor lifters, cam or eccentric disks with driven eccentrics, which enable the load-bearing platform to be raised in the range from 20mm to 40mm, or Hydraulic cylinder or a threaded spindle drive with at least one vertically arranged threaded spindle drive.

A driverless transport vehicle of the generic type, in which the lifting device for raising and lowering the load-bearing platform is designed as a threaded spindle drive with at least one vertically arranged threaded spindle drive, is from the DE 20 2013 004 209 U1 known.

Such a lifting device for raising and lowering the load-bearing platform, which is designed as a threaded spindle drive with at least one vertically arranged threaded spindle drive, enables high performance so that a heavy load can be lifted with a quick lift, and has a small installation space, so that the Screw drive can be installed in a flat and compact transport vehicle. In addition, such a threaded spindle drive enables a large stroke and thus a large stroke height of the load-bearing platform of at least 100mm, so that a load carrier picked up on the load-bearing platform can be raised so far that its parking feet or rollers are raised so far from the road surface that when the Transport vehicle, the parking feet or rollers of the transported load carriers are located above a safety field generated, for example, by laser scanners arranged on the underframe de transport vehicle, so that the safety field generated by the laser scanners is not disturbed by the parking feet or rollers of the transported load carriers. This enables the transport vehicle to be maneuvered quickly and achieves a less complex safety system for the transport vehicle.

In such a lifting device for raising and lowering the load-bearing platform, which is designed as a threaded spindle drive with at least one vertically arranged threaded spindle drive, the threaded spindle drive should, if possible, only force forces in the direction of the spindle axis of the threaded spindle drive, i.e. forces in the vertical direction, and the torques resulting from friction transferred around the spindle axis of the threaded spindle drive. Lateral forces and bending moments transverse and thus perpendicular to the spindle axis of the threaded spindle drive, which can occur, for example, as a result of acceleration or deceleration or while the transport vehicle is cornering Significantly reduce the service life of the threaded spindle drive and lead to the destruction of the threaded spindle drive, so that the lifting device does not operate reliably.

The present invention is based on the object of providing a transport vehicle of the type mentioned at the outset, in which the lifting device operates reliably.

This object is achieved according to the invention in that at least one vertically arranged linear guide device is arranged between the vehicle frame and the load-bearing platform, which is designed in such a way that forces from the linear guide device in a plane perpendicular to a vertically arranged spindle axis of the threaded spindle drive from the load-bearing platform to the vehicle frame be transmitted.

The idea according to the invention therefore consists in arranging at least one vertically arranged linear guide device between the vehicle frame and the load-bearing platform, which transfers corresponding forces from the load-bearing platform to the vehicle frame in a horizontal plane that is perpendicular to the vertically arranged spindle axis of the threaded spindle drive. Lateral forces and bending moments transverse and thus perpendicular to the spindle axis of the threaded spindle drive are thus transferred from the load-bearing platform to the vehicle frame via the linear guide device, which can effectively ensure that the threaded spindle drive only forces in the direction of the spindle axis of the threaded spindle drive, i.e. forces in the vertical direction, and transmits the torques resulting from friction about the spindle axis of the threaded spindle drive, as a result of which reliable operation of the lifting device is achieved.

In a transport vehicle according to the invention, dynamic inertia forces always occur in all possible directions during operation due to acceleration, deceleration, cornering, uneven road surfaces and vibrations. These forces and torques can be transmitted in a simple manner from the load-bearing platform to the vehicle frame with the at least one vertically arranged linear guide device, so that it is avoided that transverse forces and bending moments occur on the threaded spindle drive transversely and thus perpendicular to the spindle axis of the threaded spindle drive. This enables a long service life of the threaded spindle drive and thus reliable operation of the lifting device.

According to an advantageous embodiment of the invention, the linear guide device has at least one linear guide which has a guide rod which is fastened to the load-bearing platform and which is guided in a sliding guide arranged on the vehicle frame. With such a linear guide, forces in a horizontal plane, which is perpendicular to the vertically arranged spindle axis of the threaded spindle drive, can be easily transferred from the load-bearing platform to the vehicle frame, so that transverse forces and bending moments on the threaded spindle drive are prevented from transversely and thus perpendicularly occur to the spindle axis. The linear guide is connected to the load-bearing platform at one end by means of the guide rod and is connected to the vehicle frame in the vertical direction below the load-bearing platform by means of the sliding guide and is supported on it. One of these two connections, for example the connection of the linear guide to the load-bearing platform or to the vehicle frame, should be rigid and the other connection, for example the connection of the linear guide to the vehicle frame or to the load-bearing platform, should be flexible.

According to a particularly advantageous embodiment of the invention, the linear guide device has two linear guides, a first linear guide being designed to transfer forces from the load-bearing platform to the vehicle frame in all directions in the horizontal plane perpendicular to the vertically arranged spindle axis of the threaded spindle drive, and a second Linear guide is designed to transmit torques about a longitudinal axis of the first linear guide from the load-bearing platform to the vehicle frame. With two such linear guides, a defined transmission of the forces in the horizontal plane, which is perpendicular to the vertically arranged spindle axis of the threaded spindle drive, is possible. The first linear guide transfers forces transversely and thus perpendicular to the spindle axis of the threaded spindle drive in all directions from the load-bearing platform to the vehicle frame, while the second Linear guide absorbs torques about the longitudinal axis of the first linear guide. The second linear guide thus forms a type of torque support.

According to an advantageous embodiment of the invention, the first linear guide has a guide rod with a circular cross section, which is guided with little play in an annular sliding guide, in particular a sliding bush. With a simple structure, such a linear guide enables forces to be transmitted transversely and thus perpendicular to the spindle axis of the threaded spindle drive in all directions from the load-bearing platform to the vehicle frame.

According to an advantageous embodiment of the invention, the second linear guide has a guide rod with an angular cross-sectional profile, in particular a rectangular cross-section, which is guided in a sliding guide having an angular cross-sectional profile, in particular a rectangular sliding guide, in such a way that the guide rod on the sliding guide has little play in the transverse direction of the vehicle is guided and has a game in the vehicle longitudinal direction to the sliding guide. The guide rod arranged in the sliding guide attached to the vehicle frame thus only transmits forces in a single direction transversely and thus perpendicular to the spindle axis of the threaded spindle drive, for example in the transverse direction of the vehicle, due to the corresponding design of the play between the guide rod and the sliding guide the longitudinal axis of the first linear guide can be added.

For this purpose, the first linear guide is advantageously arranged at a distance from the second linear guide in the longitudinal direction of the vehicle. This results in a correspondingly large distance and thus lever arm of the second linear guide from the first linear guide in a simple manner, so that the second linear guide can absorb and transmit the corresponding torques about the longitudinal axis of the first linear guide.

According to an advantageous embodiment of the invention, the threaded spindle drive has a spindle nut rotatably mounted on the vehicle frame, which can be driven by means of a drive unit of the lifting device, and a threaded spindle guided in the spindle nut, which is fixedly attached to the load-bearing platform. The threaded spindle drive thus consists of a spindle nut that is attached to the The vehicle frame is rotatably mounted and is driven and rotates by means of the drive unit, and a threaded spindle guided through the spindle nut, which is prevented from rotating and for this purpose is non-rotatably fastened to the load-bearing platform. The rotation of the spindle nut driven by the drive unit is thus converted into a vertical linear movement of the threaded spindle and thus a lifting movement of the load-bearing platform.

According to a preferred embodiment of the invention, the threaded spindle drive has at least two threaded spindle drives, which are driven by the drive unit by means of a traction mechanism drive, in particular a toothed belt drive. With several threaded spindle drives, a high performance of the lifting device can be achieved in a simple manner in order to be able to lift a heavy load with a rapid stroke. Using a traction drive, in particular a toothed belt drive, several threaded spindle drives can be driven in a simple manner by a single drive unit.

According to an advantageous embodiment of the invention, the spindle nut of each threaded spindle drive is non-rotatably connected to a gearwheel, in particular a toothed belt pulley, which is driven by the traction mechanism of the traction mechanism drive, particularly a toothed belt of the toothed belt drive. The spindle nut of the corresponding threaded spindle drive is thus in each case connected to a gear, for example a toothed belt pulley, so that the gear driven by the traction means, for example the toothed belt pulley driven by the toothed belt, rotates together with the spindle nut of the corresponding threaded spindle drive.

According to an advantageous development of the invention, the traction mechanism drive has a deflecting roller rotatably mounted on the vehicle frame, over which the traction mechanism is guided, the deflecting roller being arranged concentrically to a longitudinal axis of the linear guide. A deflection roller of the traction mechanism drive can thereby be arranged concentrically around the linear guide in a space-saving manner.

The connection of the threaded spindle drive with the load-bearing platform is advantageously designed to be largely flexible. For this purpose, according to an advantageous embodiment of the invention, the threaded spindle with the Load-bearing platform attached via a spring element, in particular a rubber ring.

The connection of the threaded spindle drive to the vehicle frame is advantageously designed to be largely flexible. For this purpose, according to an advantageous embodiment of the invention, the spindle nut is rotatably mounted in the vehicle frame by means of a spherical roller bearing.

According to an advantageous development of the invention, the threaded spindle is arranged in a protective sleeve attached to the vehicle frame. With a protective sleeve arranged on the vehicle frame, in which the threaded spindle is arranged, the threaded spindle drive can be protected in a simple manner against dust whirled up by the road surface. With protective sleeves of this type, the reliability of the lifting device can be further increased with little additional effort.

According to a further development of the invention, the vehicle frame has a running gear with at least one wheel unit that can be steered about a vertical axis of rotation, the guide rod of the linear guide and / or the threaded spindle of the threaded spindle drive being arranged in such a way that the guide rod of the linear guide and / or the threaded spindle of the threaded spindle drive has a Uses free space in the rotation area of the steerable wheel unit around the vertical axis of rotation. For the undisturbed steering movement of the wheel unit around the vertical axis of rotation, a corresponding free space must be provided on the transport vehicle in the area of rotation of the steerable wheel unit and thus of the steered wheels. If the guide rod of the linear guide and / or the threaded spindle of the threaded spindle drive is arranged in such a way that the guide rod of the linear guide and / or the threaded spindle of the threaded spindle drive uses the free space available in the rotation range of the steerable wheel unit around the vertical axis of rotation, the limited space available in a compact and flat transport vehicle can be effectively used.

For this purpose, according to a preferred embodiment of the invention, the guide rod of the linear guide and / or the threaded spindle of the threaded spindle drive is arranged coaxially to the vertical axis of rotation of the steerable wheel unit.

In particular, when the steerable wheel unit is designed as a passive wheel unit steered by means of a caster, in which the horizontal axis of rotation of the steered wheel is arranged at a distance from the vertical axis of rotation, a guide rod of the linear guide and / or which is arranged coaxially to the vertical axis of rotation of the steerable wheel unit can be used Threaded spindle of the threaded spindle drive, the free space available in the range of rotation of the steerable wheel unit around the vertical axis of rotation can be used in a simple manner by the guide rod of the linear guide and / or by the threaded spindle of the threaded spindle drive.

According to an advantageous embodiment of the invention, the steerable wheel unit is designed as a double wheel with two spaced apart wheels, the guide rod of the linear guide and / or the threaded spindle of the threaded spindle drive being arranged between the two wheels of the double wheel. By using a double wheel instead of a single wheel and a corresponding distance (track) between the two wheels, it is made possible in a simple manner to incorporate the guide rod of the linear guide and / or the threaded spindle of the threaded spindle drive into the available free space in the rotation area of the steerable wheel unit without the function of the steerable wheel unit To affect the wheel unit.

According to an advantageous development of the invention, the threaded spindle drive is provided with a braking device. With a braking device of this type, in its braking position, it is prevented in a simple manner that the load-bearing platform with the picked-up load is lowered in an uncontrolled manner or lowered at an angle in the event of a malfunction or a defect in the lifting device.

According to an advantageous embodiment of the invention, the braking device is designed as a spring-loaded brake that can be electrically actuated into a release position. Such a spring-loaded brake is acted upon by a spring device in the braking position and can be acted upon in the release position by an electrical actuating device, for example an electromagnet. Using a corresponding sensor system and an electronic control device that controls the braking device, various and multiple malfunctions / defects in the lifting device can be detected in which the braking device is actuated into the braking position, for example a crack in the Traction mechanism of the traction mechanism drive or a break in a drive shaft of the drive unit. Such a spring-loaded brake that can be electrically actuated into a release position also makes it possible to control the spring-loaded brake into the braking position during normal operation of the transport vehicle with the load-bearing platform raised, so that the drive unit can be switched off to save energy.

According to an alternative and also advantageous embodiment of the invention, the braking device is designed as a claw brake acting on the gearwheel, which is actuated by a spring device in the direction of a braking position and is actuated by the traction means of the traction mechanism drive, in particular a toothed belt of the toothed belt drive, in the direction of a release position . The claw brake is thus actuated by the tensioned traction mechanism of the traction mechanism drive against the force of the spring device in the release position. If the traction mechanism breaks, the claw brake is thus urged into the braking position by the spring device, in which the claws of the claw brake engage the toothing of the gearwheel and block the threaded spindle drive in the lowering direction. With such a claw brake, the threaded spindle drive can be braked and blocked with little construction effort for the braking device in the event of a crack in the traction mechanism of the traction mechanism drive.

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

The lifting device according to the invention with the additional linear guide device enables a long and reproducible service life of the threaded spindle drive, since transverse forces and bending moments acting on the at least one threaded spindle drive are reliably avoided.

The lifting device according to the invention with the additional linear guide device has a constant drive torque over the entire lifting range, whereby a uniform lifting speed and thus a short lifting time is possible and makes it possible to make the drive unit of the lifting device small and inexpensive.

The lifting device according to the invention with the additional linear guide device enables a large lifting range of the load-bearing platform with a low complexity of the construction and thus in a cost-effective manner.

In connection with a sealed bearing of the spindle nut and a protective sleeve for the threaded spindle, a low-maintenance or maintenance-free lifting device is achieved.

The lifting device according to the invention with the additional linear guide device enables good efficiency, for example when the threaded spindle drive is designed as a ball screw drive. As a result, the drive unit of the lifting device can be made small and inexpensive and there is energy saving and a low heat input into the transport vehicle, which means that cooling of the transport vehicle is easy to implement or can be omitted entirely.

The lifting device according to the invention with the additional linear guide device enables good mechanical rigidity due to the additional linear guide device through defined and directly acting linear guides. This results in a low tendency to vibrations.

If several threaded spindle drives are used, which are driven by a traction drive, for example a toothed belt drive, a reliable mechanical synchronization of the threaded spindle drives by the traction of the traction drive results in a simple manner.

With the braking device on the threaded spindle drive, a safety brake is achieved with little construction effort, with which the threaded spindle drive can be braked and blocked in the event of a malfunction or a defect in the lifting device, for example a crack in the traction mechanism of the traction mechanism drive.

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 Gehäuse,

Figur 4

das Transportfahrzeug der Figuren 1 bis 3 mit angehobener Lastaufnahmeplattform und darauf befindlichem Ladungsträger und

Figur 5

einen Ausschnitt der Figur 3,

Figur 6

ein erfindungsgemäßes Transportfahrzeug in einer Darstellung von unten ohne Fahrwerk,

Figur 7

einen Längsschnitt eines Gewindespindeltriebs der Hubvorrichtung,

Figur 8

einen Längsschnitt einer Weiterbildung eines Gewindespindeltriebs der Hubvorrichtung,

Figur 9

einen Längsschnitt der ersten Linearführung der Linearführungseinrichtung,

Figur 10

einen Ausschnitt des Zugmitteltriebs,

Figur 11

ein erfindungsgemäßes Transportfahrzeug in einer Darstellung von unten mit lenkbaren Radeinheiten,

Figur 12

einen Längsschnitt durch eine lenkbare Radeinheit auf ebener Fahrbahnoberfläche,

Figur 13

einen Längsschnitt durch eine lenkbare Radeinheit bei einer Rampenfahrt und

Figur 14

eine Bremseinrichtung des Gewindespindeltriebs in einer vergrößerten Darstellung.

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

Figure 1

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

Figure 2

the transport vehicle of Figure 1 with raised load platform,

Figure 3

the transport vehicle of Figures 1 and 2 without housing,

Figure 4

the transport vehicle of Figures 1 to 3 with a raised load-carrying platform and load carrier on it and

Figure 5

a section of the Figure 3 ,

Figure 6

a transport vehicle according to the invention in a representation from below without chassis,

Figure 7

a longitudinal section of a threaded spindle drive of the lifting device,

Figure 8

a longitudinal section of a further development of a threaded spindle drive of the lifting device,

Figure 9

a longitudinal section of the first linear guide of the linear guide device,

Figure 10

a section of the traction drive,

Figure 11

a transport vehicle according to the invention in a representation from below with steerable wheel units,

Figure 12

a longitudinal section through a steerable wheel unit on a level road surface,

Figure 13

a longitudinal section through a steerable wheel unit when traveling on a ramp and

Figure 14

a braking device of the threaded spindle drive in an enlarged view.

In the Figures 1 to 4 a driverless, in particular autonomous, transport vehicle 1 according to the invention is shown. The transport vehicle 1 is for horizontal transport one in the Figure 4 shown load carrier LT formed, for example a pallet or a trolley. In the Figure 4 a load carrier LT designed as a trolley is shown, which carries a pallet P with a load LA located on it.

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

The underframe 2 has an outer housing 6 arranged on the vehicle frame 3 as a cladding, under which the vehicle frame 3 and the running gear 4 are arranged. The Figures 1 , 2 and 4th show the transport vehicle 1 with the housing 6 Figure 3 the housing 6 is not shown.

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

The underframe 2, in which the vehicle frame 3 and the running gear 4 are arranged, is arranged in the vertical direction below the load-bearing platform 5. The transport vehicle 1 is thus designed as a flat and compact self-propelled transport vehicle that enables the load carrier LT to be driven under and the load carrier LT to be lifted with the load-bearing platform 5 in order to transport the load carrier LT horizontally and set it down again. The navigation and control of the transport vehicle 1 takes place automatically or autonomously; as an alternative, remote-controlled operation of the transport vehicle 1 is also possible.

The chassis 4 of the transport vehicle 1 according to the invention has at least two axles. In the illustrated embodiment, the chassis consists of three axles and is supported by a central axle 10 with two non-steered wheels 10a, 10b, a front axle 11 with at least one wheel unit 11a rotatably arranged around a vertical axis V1 and thus steered, and a rear axle 12 with at least one a vertical axis V2 rotatably arranged and thus steered wheel unit 12a is formed. The front axle 11 is arranged in the vehicle longitudinal direction L of the transport vehicle 1 at a distance to the front from the central axis 10. Correspondingly, the rear axle 12 is arranged at a distance to the rear from the central axis 10 in the vehicle longitudinal direction L of the transport vehicle 1.

In the illustrated embodiment, the two wheels 10a, 10b of the central axis 10 are each designed as a drive wheel and form a drive of the transport vehicle 1. The wheels 10a, 10b designed as drive wheels are each driven by a drive unit, for example an electric drive unit. The central axis 10 is thus designed as a drive axis with two drive units. The drive unit can each be formed by an electric traction motor which drives the corresponding wheel 10a, 10b directly or with the interposition of a gear. The speed and direction of rotation of the two drive units can be controlled or regulated independently of one another, so that the transport vehicle 1 can be steered and turned on the spot by different speeds on the two wheels 10a, 10b and different directions of rotation of the wheels 10a, 10b.

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 rotatably mounted about the 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 of the transport vehicle 1.

The wheel unit 11a of the front axle 11 is designed as a double wheel with two wheels 20, 21 arranged laterally spaced from one another.

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 rotatably mounted about the 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 vehicle transverse direction Q of the transport vehicle 1.

The wheel unit 12a of the rear axle 12 is designed as a double wheel with two wheels 22, 23 arranged laterally spaced from one another.

In the Figure 1 the load-bearing platform 5 is shown in a lowered position in which the load-bearing platform 5 is located directly above the housing 6 of the underframe 2. In the Figure 2 and the Figure 4 the load-bearing platform 5 is shown in the raised position. As from the Figure 4 As can be seen, the rollers R of the load carrier LT, which is designed as a trolley, are lifted from a roadway surface FB. The load-bearing platform 5 with the load carrier LT picked up can be raised by means of the lifting device 7 to such an extent that the rollers R are raised so far from the road surface FB that when the transport vehicle 1 is driven, the rollers R of the transported load carrier LT are above one, for example, of the Underframe 2 of the transport vehicle 1 arranged laser scanners are generated security field, so that the security field generated by the laser scanners is not disturbed by the rollers R of the transported load carrier LT.

From the Figure 4 It can also be seen that the load LA transported on the load-bearing platform 5 is often larger than the base area of the transport vehicle 1, so that the transported load LA protrudes beyond the outer contour of the transport vehicle 1.

The housing 6 is fastened to the vehicle frame 3. Furthermore, on the vehicle frame 3 within the housing 6 in the vehicle interior more in the Figures 1 to 4 Components not shown in detail of the driverless transport vehicle 1 attached, for example an electric drive unit 20 of the lifting device 7, electronic controls for controlling the electric drive units of the two wheels 10a, 10b and for controlling the drive unit 20, a traction battery, which the electric drive units of the two wheels 10a , 10b and the electric drive unit 20 of the lifting device 7, as well as sensors, for example sensors for monitoring the surroundings and / or for navigating the driverless transport vehicle.

The lifting device 7 is - as from the Figures 3 and 5 can be seen - designed as a threaded spindle drive 50 with at least one vertically arranged threaded spindle drive. In the illustrated embodiment, the threaded spindle drive 50 has three threaded spindle drives 50a, 50b, 50c. The threaded spindle drives 50a, 50b, 50c are driven by the electric drive unit 20 by means of a traction drive, in the illustrated embodiment a toothed belt drive 51. The electric drive unit 20 drives the threaded spindle drives 50a, 50b, 50c via a toothed belt 53 of the toothed belt drive 51. In the exemplary embodiment shown, the threaded spindle drive 50a is arranged centrally in the rear region of the vehicle frame 3 in the transverse direction Q of the vehicle. The threaded spindle drives 50b, 50c are arranged in the front region of the vehicle frame 3 at a distance from one another in the vehicle transverse direction Q.

The threaded spindle drives 50a, 50b, 50c are preferably designed as ball screws in order to achieve a high efficiency of the threaded spindle drives 50a, 50b, 50c. As a result, the drive unit 20 can be made correspondingly small.

The threaded spindle drive 50a, 50b, 50c each has - as in FIG Figure 7 which represents a longitudinal section through one of the threaded spindle drives 50a, 50b, 50c - a spindle nut 55 which is rotatably mounted on the vehicle frame 3 and which can be driven by means of the electric drive unit 20 of the lifting device 7. A vertically arranged threaded spindle 56 is guided in the spindle nut 55 and is fastened in a rotationally fixed manner to the load-bearing platform 5, so that the threaded spindle 56 is prevented from rotating.

The spindle nut 55 of each threaded spindle drive 50a, 50b, 50c is non-rotatably connected to a gear 57, in particular a toothed belt pulley 58, with which the toothed belt 53 of the toothed belt drive 51 is in positive engagement.

The threaded spindle 56 of the corresponding threaded spindle drive 50a, 50b, 50c is each flexibly connected to the load-bearing platform 5, for which purpose a spring element 60, for example a rubber ring, is provided. The spring element 60 is arranged between the load-bearing platform 5 and a fastening screw 61 screwed into the upper end face of the threaded spindle 56.

The spindle nut 55 of the corresponding threaded spindle drive 50a, 50b, 50c is flexibly connected to the vehicle frame 3, for which purpose the spindle nut 55 is rotatably mounted on the vehicle frame 3 by means of a spherical roller bearing 62. The spherical roller bearings 62 are designed as sealed spherical roller bearings in the illustrated embodiment.

In the Figure 8 , in which a development of the corresponding threaded spindle drives 50a, 50b, 50c is shown, the threaded spindle 56 is arranged in a protective sleeve 65 fastened to the vehicle frame 3. The protective sleeves 65 have the function of a dust protection sleeve which protect the threaded spindles 56 of the threaded spindle drives 50a, 50b, 50c against dust whirled up by the road surface. The protective sleeves 65 are preferably made of plastic. In the exemplary embodiment shown, the protective sleeves 65 are clipped into a groove 66 on the vehicle frame 3.

As from the Figure 5 As can be seen, the electric drive unit 20 of the lifting device 7 is arranged on the vehicle frame 3 laterally next to the threaded spindle drive 50a. The drive unit 20 drives a toothed belt pulley 70. A deflection roller 71 is rotatably mounted on the vehicle frame 3 between the toothed belt pulley 70 and the toothed belt slide 58 of the threaded spindle drive 50a. Laterally next to the threaded spindle drive 50a on the vehicle side opposite the drive unit 20, a further deflection roller 72 is rotatably mounted on the vehicle frame 3. The toothed belt 53 of the toothed belt drive 51 is via the toothed belt pulley 70, the deflection roller 71, the toothed belt slide 58 of the threaded spindle drive 50a, the other Deflection roller 72, the toothed belt slide 58 of the threaded spindle drive 50b and the toothed belt pulley 58 of the threaded spindle drive 50c, the toothed belt 53 being positively engaged with the toothed belt pulleys 70 and 58.

The toothed belt drive 51 also has a tensioning device for the toothed belt 53, which is not shown in detail in the figures.

If the electric drive unit 20 drives the toothed belt pulley 70, all toothed belt pulleys 58 of the threaded spindle drives 50a, 50b, 50c are driven via the toothed belt 53, whereby the spindle nuts 55 of the threaded spindle drives 50a, 50b, 50c are rotated by means of the toothed belt pulleys 58 and according to the direction of rotation of the Spindle nuts 55 extend the threaded spindles 56, which are fastened non-rotatably on the load-bearing platform 5, upwards to raise the load-bearing platform 5 or retract them downward to lower the load-bearing platform 5.

If possible, the threaded spindle drives 50a, 50b, 50c should only force forces in the direction of the spindle axis SA of the threaded spindle drive 50a, 50b, 50c, i.e. forces in the vertical direction, and the torques resulting from friction around the spindle axis SA of the threaded spindle drive 50a, 50b, 50c transfer. Lateral forces and bending moments transverse and thus perpendicular to the spindle axis SA of the threaded spindle drive 50a, 50b, 50c, which occur, for example, when the transport vehicle 1 accelerates or decelerates or while cornering, can significantly reduce the service life of the threaded spindle drive 50a, 50b, 50c and up to lead to the destruction of the threaded spindle drive 50a, 50b, 50c.

In a transport vehicle 1 according to the invention, dynamic inertia forces always occur in all possible directions during operation due to acceleration, deceleration, cornering, uneven road surfaces and vibrations. According to the invention, these forces and torques are transmitted from the load-bearing platform 5 to the vehicle frame 3 with at least one vertically arranged linear guide device 80, so that the linear guide device 80 avoids transverse forces and bending moments on the threaded spindle drives 50a, 50b, 50c transversely and thus perpendicular to the spindle axis SA of the Screw spindle drives 50a, 50b, 50b occur.

The vertically arranged linear guide device 80 is arranged between the vehicle frame 3 and the load-bearing platform 5 and is designed in such a way that forces from the linear guide device 80 in a horizontal plane lying perpendicular to the vertically arranged spindle axes SA of the threaded spindle drives 50a, 50b, 50b from the load-bearing platform 5 to the Vehicle frame 3 are transferred.

In the illustrated embodiment, the linear guide device 80 consists of two linear guides 81, 82. The first linear guide 81 consists - as from the Figure 9 can be seen from a vertically arranged guide rod 85 which is fastened to the load-bearing platform 5 and which is guided in a sliding guide 86 arranged on the vehicle frame 3. For this purpose, the guide rod 85 is fastened to the load-bearing platform 5 at the upper end area and is supported vertically below the load-bearing platform 5 via the sliding guide 86 on the vehicle frame 3. The second linear guide 82 consists of a vertically arranged guide rod 87 which is fastened to the load-bearing platform 5 and which is guided in a sliding guide 88 arranged on the vehicle frame 3. For this purpose, the guide rod 87 is fastened to the load-bearing platform 5 at the upper end area and is supported vertically below the load-bearing platform 5 via the sliding guide 88 on the vehicle frame 3.

In order to transfer the forces that occur with the two linear guides 81, 82 in a defined manner from the load-bearing platform 5 to the vehicle frame 3, the first linear guide 81 is designed, forces in all directions in the perpendicular to the vertically arranged spindle axes SA of the threaded spindle drives 50a, 50b, 50c to transfer lying plane from the load-bearing platform 5 to the vehicle frame 3. The second linear guide 82 is designed to transmit torques about a vertical longitudinal axis LG of the first linear guide 81 from the load-bearing platform 5 to the vehicle frame 3.

The guide rod 85 of the first linear guide 81 has this - as from the Figures 5 , 6th and 9 It can be seen - has a circular cross-section and is guided with little play in an annular sliding guide 86, which is designed as a sliding bush and is attached to the vehicle frame 3. The guide rod 85 can thus forces in all Directions in the plane lying perpendicular to the vertically arranged spindle axes SA of the threaded spindle drives 50a, 50b, 50c are transferred from the load-bearing platform 5 to the vehicle frame 3.

The guide rod 87 of the second linear guide 82 has this - as from the Figures 5 and 6th can be seen - a rectangular cross-section, and is guided in a rectangular slide guide 88 attached to the vehicle frame 3 in such a way that the guide rod 87 is guided on the slide guide 88 in the vehicle transverse direction Q with little play and the guide rod 87 in the vehicle longitudinal direction L to the slide guide 88 forwards and backwards each has a game. The guide rod 88 can therefore only transmit forces in one direction, in the illustrated embodiment in the vehicle transverse direction Q, transversely to the spindle axis SA of the threaded spindle drives 50a, 50b, 50c from the load-bearing platform 5 to the vehicle frame 3. The second linear guide 82 is arranged at a distance from the first linear guide 81 in the vehicle longitudinal direction L, so that the guide rod 87 of the second linear guide 82, which is only supported in the vehicle transverse direction Q in the sliding guide 88, absorbs torques about the vertical longitudinal axis LG of the first linear guide 81 from the load-bearing platform 5 the vehicle frame 3 transmits.

As from the Figure 11 As can be seen, the vertically moving guide rod 87 of the second linear guide 82 is arranged such that the guide rod 87 of the second linear guide uses an existing free space in the rotation range of the steerable wheel unit 11a about the vertical axis of rotation V1.

Furthermore, the threaded spindle 56 of the threaded spindle drive 50a, which moves in the vertical direction, is arranged such that the threaded spindle 56 of the threaded spindle drive 50b uses an existing free space in the rotation area of the steerable wheel unit 12a about the vertical axis of rotation V2.

With such an arrangement of the guide rod 87 of the second linear guide 82 and the threaded spindle 56 of the threaded spindle drive 50a, the space available in the flat and compact transport vehicle 1 for installing the corresponding components can be optimally used.

In order to provide a corresponding free space for such an arrangement of the guide rod 87 of the second linear guide 82 and the threaded spindle 56 of the threaded spindle drive 50a, as shown in FIG Figure 12 It can be seen - the bearing of the steerable wheel unit 12a about the vertical axis of rotation V2 is designed as a flat bearing 100 with a large diameter. In the Figure 12 the structure of the steerable wheel unit 12a is shown, in the area of which the threaded spindle 56 of the threaded spindle drive 50a is arranged. The steerable wheel unit 11a, in the area of which the guide rod 87 of the second linear guide 82 is arranged, has an analogous structure. Furthermore, the steerable wheel unit 12a is provided as a double wheel with two wheels 22, 23 arranged in parallel and laterally spaced from one another, instead of a central single wheel. For this purpose, the wheels 22, 23 are arranged laterally spaced from one another. The guide rod 87 of the second linear guide 82 is arranged between the two wheels 20, 21 of the double wheel of the steerable wheel unit 11a. The threaded spindle 56 of the threaded spindle drive 50a is accordingly arranged between the two wheels 22, 23 of the double wheel of the steerable wheel unit 11a

The steerable wheel unit 11a and the steerable wheel unit 12a can be attached directly to the vehicle frame 3. In the Figure 13 an alternative embodiment is shown in which the steerable wheel unit 12a is movably suspended on the vehicle frame 3 in order to be able to compensate for uneven road surfaces and to enable ramps to be driven on. It goes without saying that the steerable wheel unit 11a can also be suspended movably on the vehicle frame 3.

The pulley 71 of the toothed belt drive 51 is - as from the Figures 5 , 9 and 10 It can be seen - arranged concentrically to the longitudinal axis LG of the first linear guide 81 in a space-saving manner. For this purpose, the deflection roller 71 is rotatably mounted on a tubular fastening flange 89 of the vehicle frame 3, in which the sliding guide 86 of the first linear guide 81 is arranged.

In the illustrated embodiment, the threaded spindle drive 50 is still - as from FIG Figure 5 can be seen - provided with a braking device 90. In the illustrated embodiment, a corresponding braking device 90 is provided on each threaded spindle drive 50a, 50b, 50c for this purpose.

The braking device 90 is in each case designed as a claw brake 91 acting on the gear 57 and thus on the toothed belt pulley 58, which is non-rotatably connected to the spindle nut 55 of the corresponding threaded spindle drive 50a, 50b, 50c.

The claw brake 91 consists - as from the Figure 14 can be seen in more detail - from a lever 92 pivotably mounted on the vehicle frame 3 about a vertical pivot axis S. The lever 92 is provided on a first lever arm 92a with tooth-like claws 93 which can be brought into engagement with the teeth on the outer circumference of the toothed belt pulley 58 and engage can. The lever 92 is actuated by a spring device 94 in the direction of a braking position. The spring device 94 is supported on the vehicle frame 3 and is connected to the lever 92. In the exemplary embodiment shown, the spring device 94 is designed as a compression spring which acts on the lever 92 with respect to the pivot axis S opposite the claws 93. In the braking position, the claws 93 of the lever 92 engage the teeth of the toothed belt pulley 58. The lever 92 is preloaded by the spring device 94 in such a way that, in the braking position, the toothed belt pulley 58 and thus the spindle nut 55 are blocked in the direction of the lowering of the load-bearing platform 5.

The claw brake 91 is actuated by the traction mechanism of the traction mechanism drive, in the illustrated embodiment by the toothed belt 53 of the toothed belt drive, in the direction of a release position. During normal operation of the lifting device 7, the claw brake 91 is released against the force of the spring device 94 in that the tensioned toothed belt 53 of the toothed belt drive pivots the lever 92 against the force of the spring device 94 about the pivot axis S into a release position. For this purpose, the lever 92 has a second lever arm 92b which extends to the toothed belt 53 and which is connected to the toothed belt 53. The second lever arm 92b is thus actuated by the toothed belt 53.

In order to achieve contact between the second lever arm 92b of the lever and the toothed belt 53 with as little friction and wear as possible, a toothed wheel 95 is arranged on the second lever arm 92b and is in positive engagement with the toothed belt 53. The gear 95 is on for this purpose the second lever arm 92b is mounted rotatably about a vertical axis of rotation DA by means of a suitable, smooth-running bearing.

When the lifting device 7 is in operation with the toothed belt 53 driven, the toothed wheel 95 thus runs with the toothed belt 53. The force from the belt tension of the toothed belt 53 is thus transmitted via the gear 95 to the lever arm 92b in order to actuate the lever 92 against the force of the spring device 94 into the release position of the claw brake 91.

Should the toothed belt 53 tear, the lever 92 is actuated by the spring device 94 into the braking position due to the lack of belt tension of the toothed belt 53, in which the claws 93 engage the toothing of the toothed belt pulley 58 and the toothed belt pulley 58 is blocked in the direction of the lowering of the load-bearing platform 5. An uncontrolled or oblique lowering of the load-bearing platform 5 in the event of a crack in the toothed belt 53 is thus reliably prevented.

The invention is not limited to the illustrated embodiment. It goes without saying that more than three threaded spindle drives can also be provided.

As an alternative to a toothed belt drive 51, the traction mechanism drive can also be designed as a chain drive.

Claims (19)

Driverless transport vehicle (1), in particular for the transport of load carriers (LT), which has a mobile underframe (2) and a load-bearing platform (5) for receiving a load carrier (LT), the underframe (2) in the vertical direction below the load-bearing platform (5) is arranged and the load-bearing platform (5) can be raised and lowered in the vertical direction by means of a lifting device (7) on a vehicle frame of the underframe (2), the lifting device (7) being a threaded spindle drive (50) with at least one vertically arranged Threaded spindle drive (50a; 50b; 50c) is designed, characterized in that at least one vertically arranged linear guide device (80) is arranged between the vehicle frame (3) and the load-bearing platform (5), which is designed in such a way that the linear guide device (80) Forces in a spindle axis (SA) of the threaded spindle drive (50 a; 50b; 50c) lying level can be transferred from the load-bearing platform (5) to the vehicle frame (3). Driverless transport vehicle according to Claim 1, characterized in that the linear guide device (80) has at least one linear guide (81; 82) which has a guide rod (85; 87) which is fastened to the load-bearing platform (5) and which is in a position on the vehicle frame (3 ) arranged sliding guide (86; 88) is guided. Driverless transport vehicle according to Claim 1 or 2, characterized in that the linear guide device (80) has two linear guides (81, 82), a first linear guide (81) being formed, forces in all directions in the spindle axis (SA) which is perpendicular to the vertically arranged spindle ) of the threaded spindle drive (50a; 50b; 50c) lying plane from the load-bearing platform (5) to the vehicle frame (3), and a second linear guide (82) is designed, torques about a longitudinal axis (LG) of the first linear guide (81) to be transferred from the load-bearing platform (5) to the vehicle frame (3). Driverless transport vehicle according to Claim 3, characterized in that the first linear guide (81) has a guide rod (85) with a circular cross-section, which is guided with little play in an annular sliding guide (86), in particular a sliding bush. Driverless transport vehicle according to Claim 3 or 4, characterized in that the second linear guide (82) has a guide rod (87) with an angular cross-sectional profile, in particular a rectangular cross-section, which is inserted in a sliding guide (88) having an angular cross-sectional profile, in particular a rectangular sliding guide (88) is guided in such a way that the guide rod (87) is guided on the sliding guide (88) with little play in the transverse direction of the vehicle (Q) and has a play in the longitudinal direction (L) of the vehicle with respect to the sliding guide (88). Driverless transport vehicle according to one of Claims 3 to 5, characterized in that the first linear guide (81) is arranged at a distance from the second linear guide (82) in the longitudinal direction (L) of the vehicle. Driverless transport vehicle according to one of Claims 1 to 6, characterized in that the threaded spindle drive (50a; 50b; 50c) has a spindle nut (55) which is rotatably mounted on the vehicle frame (3) and which can be driven by means of a drive unit (20) of the lifting device (7) is, and has a threaded spindle (56) guided in the spindle nut (55) and fastened in a rotationally fixed manner to the load-bearing platform (5). Driverless transport vehicle according to one of claims 1 to 7, characterized in that the threaded spindle drive (50a; 50b; 50c) has at least two threaded spindle drives (50a, 50b, 50c) which are driven by the drive unit by means of a traction drive, in particular a toothed belt drive (51) (20) are driven. Driverless transport vehicle according to Claim 8, characterized in that the spindle nut (55) of each threaded spindle drive (50a; 50b; 50c) is non-rotatably connected to a toothed wheel (57), in particular a toothed belt pulley (58), which is driven by the traction mechanism of the traction mechanism drive, in particular a toothed belt (53) of the toothed belt drive (51). Driverless transport vehicle according to claim 8 or 9, characterized in that the traction mechanism drive has a deflection roller (71) rotatably mounted on the vehicle frame (3) over which the traction mechanism is guided, the deflection roller (71) concentric to a longitudinal axis (LG) of the Linear guide (81; 82) is arranged. Driverless transport vehicle according to one of Claims 7 to 10, characterized in that the threaded spindle (56) is attached to the load-bearing platform (5) via a spring element (60), in particular a rubber ring. Driverless transport vehicle according to one of Claims 7 to 11, characterized in that the spindle nut (55) is rotatably mounted in the vehicle frame (3) by means of a spherical roller bearing (62). Driverless transport vehicle according to one of Claims 7 to 12, characterized in that the threaded spindle (56) is arranged in a protective sleeve (65) fastened to the vehicle frame (3). Driverless transport vehicle according to one of Claims 1 to 13, characterized in that the vehicle frame (3) has a chassis (4) with at least one wheel unit (11a; 12a) which can be steered about a vertical axis of rotation (V1; V2), the guide rod (85 ; 87) of the linear guide (81; 82) and / or the threaded spindle (56) of the threaded spindle drive (50a; 50b; 50c) is arranged such that the guide rod (85; 87) of the linear guide (80; 81) and / or the The threaded spindle (56) of the threaded spindle drive (50a; 50b; 50c) uses a free space in the range of rotation of the steerable wheel unit (11a; 12a) about the vertical axis of rotation (V1; V2). Driverless transport vehicle according to Claim 14, characterized in that the guide rod (85; 87) of the linear guide (80; 81) and / or the threaded spindle (56) of the threaded spindle drive (50a; 50b; 50c) is coaxial with the vertical axis of rotation (V1; V2 ) the steerable wheel unit (11a; 12a) is arranged. Driverless transport vehicle according to claim 14 or 15, characterized in that the steerable wheel unit (11a; 11b) is designed as a double wheel with two spaced apart wheels (20, 21; 22, 23), the guide rod (85; 87) of the linear guide ( 80; 81) and / or the threaded spindle (56) of the threaded spindle drive (50a; 50b; 50c) is arranged between the two wheels (20, 21; 22, 23) of the double wheel. Driverless transport vehicle according to one of Claims 1 to 16, characterized in that the threaded spindle drive (50) is provided with a braking device (90). Driverless transport vehicle according to Claim 17, characterized in that the braking device (90) is designed as a spring-loaded brake which can be electrically actuated into a release position. Driverless transport vehicle according to claim 17, characterized in that the braking device (90) is designed as a claw brake (91) which acts on the gearwheel and which is actuated by a spring device (94) in the direction of a braking position and by the traction mechanism of the traction mechanism drive, in particular the Toothed belt (53) of the toothed belt drive (51) is actuated in the direction of a release position.

Images