WO2021185894A2

WO2021185894A2 - Tracking device for a pv system (central tube and support structure for pv modules)

Info

Publication number: WO2021185894A2
Application number: PCT/EP2021/056796
Authority: WO
Inventors: Bernd Zwingmann; Thomas Keck; Willem LANDMAN; Markus BALZ
Original assignee: Sbp Sonne Gmbh; Shenzhen ATEC Energy & Environment Co., Ltd.
Priority date: 2020-03-20
Filing date: 2021-03-17
Publication date: 2021-09-23
Also published as: EP4122098A2; CN112054755A; CN112054755B; DE102020107793A1; WO2021185894A3

Abstract

Disclosed is a PV system which includes a tracking device and is very light-weight and cost-effective to manufacture, while being subjectable to heavy loads and having a very simple design, requiring only a small amount of material. The PV system is therefore relatively light-weight and is nevertheless very robust.

Description

Title: Tracking device for a PV system (central tube and support structure for PV modules)

description

The power generation of PV systems can be significantly increased if the PV modules can track the position of the sun over the course of a day. This has made it possible to increase electricity generation by 30 to 40%.

A common concept of such a tracking device provides a central tube that is as torsionally stiff as possible and that is rotatably mounted on several supports. One or two rows of PV modules are arranged on an upper side of the central tube. The central tube can be adjusted with the help of a (rotary ) Drive can be rotated. The PV modules attached to the central tube take part in this rotary movement and are thus tracked to the sun.

In the PV systems available on the market with a 2P configuration, the PV modules are attached to the central tube with the help of purlins, the length of which is roughly twice the length of a PV module. These purlins protrude outward orthogonally to the longitudinal axis of the central tube and each carry a PV module on both sides of the central tube. As a result, the PV modules lie on the purlins over their entire length and are held and supported by them.

For economic reasons, efforts are made to make the central tubes very long and to provide a (rotary) drive for the central tube in the middle of the central tube. Examples of this concept are described in US 2017/0359017 A1, US 2018/0073773 A1 and US 2017/0187327 A1. This concept has proven itself in practice.

In PV systems with central tubes, the central tube is subjected to torsion and bending due to wind loads or weight forces. It is particularly important to limit torsion, as otherwise the PV modules mounted on the central tube will be damaged.

This applies to everything for wind-induced dynamic torsion effects, such as so-called "galopping". Understood by that wind-induced torsional vibrations of the central tube, which increase from a certain wind speed to such an extent that the PV modules arranged on the central tube are damaged. In the worst case, "gallopping" can lead to a total loss of the PV system.

The invention is based on the object of optimizing this concept with a view to economic efficiency, availability and service life as well as installation and operating costs, taking into account the specific boundary conditions of outdoor PV systems.

This object is achieved according to the invention by a tracking system for a PV system comprising a central tube, several spaced-apart supports, a rotary drive for the central tube, the central tube being rotatably mounted on the supports, the central tube being composed of several segments, with two adjacent segments are plugged into one another directly or indirectly via a sleeve to form a form-fitting plug connection, and the plug connection is suitable for the transmission of torques and / or bending moments.

The direct plug-in connection according to the invention of segments of the central tube or indirectly using a sleeve makes it possible to manufacture the segments in a factory and to transport them by land or sea to the location of the PV system. Industrial production increases quality and lowers manufacturing costs. at With the tracking device according to the invention, the restriction in the length of the segments, which is caused by the transport from the factory to the location of the PV system, is converted into an advantage. The form-fitting plug connection between two segments can transmit the bending and torsional moments that occur during operation. According to the invention, the connection points between two segments are placed at the locations where the bending moments and / or torques acting on the central tube are large. For example, a plug connection according to the invention is preferably provided where the central tube is rotatably mounted on the supports and / or the rotary drive introduces the torque required to pivot the central tube into the central tube. In an overlapping area of the plug connection, the material thickness is in many cases twice as great as in the other areas of the central tube; assuming that the segments and the socket have the same wall thickness. But you can also choose a larger wall thickness of the sleeve. The form-fitting plug connection according to the invention with or without a sleeve means that the wall thickness of the central tube is at least doubled at the connection points. As a result, higher torques and bending moments can also be transmitted there without the central tube failing.

The person skilled in the art normally strives to place the connection of components in zones in which no high mechanical stresses occur. The invention "disregards" this rule and uses the sleeve for local Reinforcement of the central tube in particularly stressed areas. In other words: the wall thickness of the central tube can be reduced in the less stressed areas.

The object mentioned at the beginning is also achieved according to the invention by a tracking system for a PV system comprising a central tube, several spaced-apart supports and a rotary drive for the central tube, the central tube being rotatably mounted on the supports, with purlins on an upper side of the central tube are attached so that they protrude on both sides of the central tube and a length L _{I3 of} the purlins is less than 0.5x the length of a PV module, so that the purlins on both sides of the central tube by only about a quarter of the Extend the length of a PV module beyond the central tube.

This reduces the material used for the purlins to less than 25%, assuming that the length of "normal" purlins is more than twice the length of a PV module. This reduces the material costs and the system weight considerably. In addition, the arrangement according to the invention is lower and offers a smaller surface area for wind and storm, thereby reducing the wind-induced excitations of the tracking device and the resulting dangers.

In the case of the invention, the frames that are already present in PV modules rest at one end on the short purlins and are connected to them there. As a result, the frame of each PV module takes on the "load-bearing function" that the very long purlins take on in conventional tracking devices. This reduces weight, material usage and costs.

It is possible to mount one or two rows of photovoltaic modules (hereinafter PV modules) on the central pipe with the help of the purlins. In the figures, two rows of PV modules are always shown.

It has proven to be advantageous if the central tube consists of a closed sheet metal profile that has been folded over several times. It is possible to assemble the central tube from two halves and to connect them to one another along the joint by clinching, riveting, gluing and / or welding. This creates a very torsionally stiff central tube. The central tube or its segments can be manufactured inexpensively from thin sheet metal, in particular sheet steel or aluminum sheet. A wall thickness of 2 mm is sufficient in many cases.

The segments of the central tube can be produced, for example, in a length of 10 meters and then transported by land / sea to the location of the PV system.

It has proven to be advantageous if the central tube has an octagonal, axially symmetrical cross section, a height H of the central tube being greater than is a width B of the central tube. This cross section allows the load capacity of the central tube to be adapted to the loads that actually occur. If the height of the central tube is greater than its width, the bending moments resulting from the weight of the PV modules and the torsional moments occurring during operation can be absorbed. The stress on the material is relatively even over the circumference of the central tube. The central tube according to the invention is therefore very light and inexpensive and nevertheless very resilient and powerful.

When the sleeve is pushed into the interior of segments of the central tube (hereinafter referred to as inner sleeve), it has a cross section that enables a positive fit with the inner cross section of the segments. The clearance between the socket and the segments is small; it can even be zero.

The outer contour of the inner sleeve and the inner cross-section of the segments do not necessarily have to be geometrically similar; For example, the inner sleeve can be designed as a tube with eight ribs, with one rib being received in one corner of the segment without play or with little play. This also results in a form-fitting connection between the inner sleeve and the segment.

In a corresponding manner, the sleeve (outer sleeve), when it is pushed onto the segments of the central tube, has an inner cross-section which is designed in such a way that it can be pushed onto the segments with little play.

In addition, it is possible to connect the segments to one another by means of screws or rivets in order to effectively prevent unwanted "wandering" of the sleeve on the central pipe.

The transmission of bending moments and torques takes place via the large-area form fit between the socket and the segments of the central tube or directly between the segments of the central tube.

The sleeve can be produced, for example, by extrusion. Of course, it is also possible to manufacture the sleeve from folded sheet metal, similar to the segments of the central tube. The length and wall thickness of the socket are essentially determined by the bending moments that the socket has to transmit.

In order to be able to fasten the PV modules to the "top" of the central tube and to be able to support the PV modules with the aid of struts, several fastening straps are provided at regular intervals on the segments.

The fastening straps are usually welded-on sheet metal straps.

As a rule, four fastening straps are arranged in one plane, the normal vector of which runs parallel to the longitudinal axis of the central tube. The top two Fastening straps are used to connect a short purlin to the central tube. A PV module is attached to this short purlin, for example by screwing or riveting the frame of the PV module to the purlin.

A strut that supports the PV module from below is attached to each of the two lower fastening straps. The struts are connected to the frame of the PV module. The distance of this connection from the support of the frame on the purlins is 0.4 m to about half the length of a PV module. As a result, the weight forces of the PV module are introduced into the central tube easily and with little material expenditure.

The struts, which are attached to the underside of the central tube, are shorter than a PV module and support this PV module on its underside. As a result, the frame of the PV module, which is already present, is integrated into the PV system according to the invention as a load-bearing element. This saves construction costs and reduces the use of materials. Both improve the economy of the PV system according to the invention.

Basically, it is desirable if the angle between the frame of the PV module and the struts is as large as possible. It should be at least 10 °, but preferably more than 15 ° and ideally even more than 20 °. Then the forces that act on the frame of the PV module and the struts are minimal. In principle, this is supported by the cross-section of the central tube according to the invention. In order to increase this angle without changing the height H of the central tube, it is possible to provide a spacer between the underside of the central tube and the bearing point of the strut.

In order to be able to introduce the torques required for tracking the PV modules into the central tube, a flange is welded to the socket or a segment of the central tube. Alternatively, the flange can also be connected to the sleeve or the segment by clinching, riveting and / or gluing. This flange has to absorb very large forces and is therefore made of relatively thick sheet metal.

In order to improve the introduction of the load from the flange into the central tube or the socket, a reinforcement plate is provided in accordance with the invention in the interior of the central tube or the socket and, if necessary, welded in place. This causes a local reinforcement of the central pipe where the flange is welded to the central pipe or the socket. In addition, the welding of the thick-walled flange to the relatively thin-walled segment or the relatively thin-walled sleeve is facilitated. In addition, the load transfer from the flange into the segment or the socket is improved.

However, it is also possible to push two segments directly into one another and thereby implement the plug connection according to the invention without a sleeve. In this case a first segment has a slightly smaller outer contour than the other segment, so that the first segment can be pushed into the other segment without play or with little play to form a plug connection. A connecting element with a flange and a lever can be arranged in the overlapping area of this plug connection.

The connecting element is preferably open on one side so that it can be pushed onto the central tube at any desired point and can be fixed there, for example by means of screws. The transmission of torque between the central tube and the connecting element takes place in a form-fitting manner via the outer contour of the central tube and the inner contour of the connecting element.

According to the invention it is provided that the drive for pivoting or rotating the central tube is a linear drive, one end of which is rotatably mounted on the flange or a lever formed on the flange. The other end of the drive is attached at least indirectly to a support of the tracking device. As a rule, you will screw a bracket to the support, which in turn takes the end of the linear drive.

Electric linear drives (that is, electromechanical screw drives), hydraulic cylinders or pneumatic cylinders can be used as linear drives. The construction according to the invention is designed and suitable for all types of linear drives. Some aspects of the invention are summarized again below: The central tube is subjected to torsional loads and during operation

Exposed to bending moments that vary along its length. The central pipe must have a certain rigidity and its construction must not fail under any of the loads occurring during operation (normal operation, storm, snowfall).

In order to achieve an efficient material utilization, it is desirable to load the material almost equally at all points on the central tube, so that a good material utilization is achieved. At the same time, the central tube should be simple and inexpensive to manufacture. The selected octagonal cross-section, the height H of which is greater than its width B, fulfills these boundary conditions in an excellent way. Because there are intermediate surfaces between the flat surfaces (top, bottom and side walls) of the central tube, local kinking problems are avoided. It is also possible to introduce local material deformations (e.g. in the form of beads) into the flat surfaces of the central tube in order to further reduce the risk of bulging due to local overloads.

Another problem with thin-walled tubes is the introduction of forces and / or torques into these tubes. According to the invention it is provided that fastening straps are attached to the Central pipe to be welded. The purlins and struts according to the invention are mounted on these fastening straps.

The tabs or fastening tabs according to the invention are preferably welded to the intermediate surfaces of the central tube and are shaped in such a way that they fill the "corners" created by the preferably octagonal tube section. The resulting rectangular cross-section of the central tube in this plane facilitates the transport of the central tubes. Looking at the torsional load and the

Bending stress on the central tube, it becomes clear that under certain load conditions, both the torsional and the bending moment are locally different. In other words: the loads are a function of the location or the distance from the rotary drive. Normally, a central pipe is dimensioned in such a way that it can cope with the most unfavorable load case at any point, although this load case only occurs in a few places. The result is an oversized central tube that is very heavy and more expensive than necessary.

According to the invention, it is provided that adjacent segments of the central tube are positively connected by sleeves, preferably in the areas in which locally high torsional loads and / or high bending loads occur during operation. These are usually the places where the central tube is rotatably mounted on the supports. The sleeves create overlapping areas in which the wall thicknesses of the central pipe and sleeve add up. Due to the locally greater wall thickness, the stresses [N / mm ² ] occurring in the central pipe and the socket are reduced and local overloading of the central pipe is effectively prevented.

The octagonal profile of the pipe and a large overlap between the socket and segments of the central pipe make it possible to transfer both bending and torsional moments from one segment to another. The overlapping of pipes at highly stressed points doubles the torsional strength and the moment of inertia and thus reduces stress peaks. This enables thinner elements in areas with little stress on the pipe, which reduces material consumption with constant cross-sections within an element.

In order to effectively transfer torsional loads, the pipes can either be provided with a geometric locking profile (such as the octagonal shape), which is able to transfer the torsional loads. To the

Transfer of bending loads, a minimum length of the overlap is required.

Another problem is the introduction of torques from the actuating drive into the central tube. This is done according to the invention by a flange on which a lever can be formed. A linear drive according to the invention is in turn attached to the lever. According to the invention it is provided that where the flange to the sleeve and / or a segment of the central tube is welded, a reinforcing plate is welded onto the inside of the sleeves and / or the segment. This leads to a better introduction of force into the central tube and simplifies the welding process.

PV tracking systems with a (long) central tube and only one rotary drive can twist under wind load. These wind-induced "harmonic" torsional vibrations ("galopping") can reach large amplitudes and destroy the tracking device and the PV modules. Therefore, they must be prevented or limited.

This is done by a twist lock according to the invention. When the torsion tube reaches a defined (rotary) position at the place where the locking device is installed (usually this is a support of the PV system), the rotary lock according to the invention is activated and, as a result, further torsion of the central tube is prevented at this point .

Locking device is installed on a support which is located relatively far from the drive of the central tube. There the wind-induced torsion of the central tube is relatively large. The twist lock according to the invention limits the torsion to an uncritical level. As a result, gallopping is prevented.

In the PV system according to the invention, a purlin with a reduced length is used, which is only long enough to accommodate the inner fastening tabs of the module frame / panel to connect the central pipe. The outer mounting bracket is supported by an additional diagonal strut that is connected to the lower mounting bracket on the bottom of the central tube. The strut acts as a compression and tension element and reduces the bending in the purlin.

Further advantages and advantageous embodiments of the invention can be found in the following drawings and their description and in the claims.

All of the features disclosed in the drawing and the description thereof in the claims can be essential to the invention both individually and in any combination.

drawing

Show it:

Figure 1: An isometry of an inventive

PV system with tracking system of a PV system according to the invention,

FIG. 2: an isometric view of part of the tracking system according to the invention,

FIG. 3: a side view of part of the tracking system according to the invention,

FIG. 4: the cross section through an exemplary embodiment of a central tube according to the invention, Figures 5 and 6: Alternatives to the invention

Connection of segments of the central tube,

Figures 7 and 8: an embodiment of a connection according to the invention between a flange and the central tube or a sleeve,

Figures 9 and 10: a further embodiment of a direct connection according to the invention of two segments without a sleeve,

Figures 11 and 12: a further embodiment of a connection according to the invention between a flange and the central tube or a sleeve,

FIGS. 13 to 16: The mounting according to the invention of the central tube on a polygon in various representations;

Figures 17 to 20: Details of the inventive arrangement and fastening of the PV modules on the central tube,

FIGS. 21 and 22: two views of the PV tracker; FIG. 23: a flange piece in three views and

FIG. 24: a half-shell in three views.

Description of exemplary embodiments:

In FIG. 1, a PV system with a tracking system according to the invention is shown in a view from the rear. The entire PV system with the tracking system according to the invention is provided with the reference number 1. The PV system 1 comprises a multiplicity of PV modules 3 which are arranged on both sides of a central tube 5. The central tube 5 is rotatably mounted on supports 7. The structural details of this storage cannot be seen in FIG. In FIG. 1, but also in FIG. 2, it can be seen that each PV module 3 has a frame 9. This frame 9 is used for stabilization, so that the

Glasses and semiconductor layers of the actual PV module 3 are not exposed to any inadmissible mechanical loads. The frame 9 usually consists of four aluminum profiles which are connected to one another at the corners.

Struts 11 are arranged between the “underside” of the central tube 5 and the frame 9 of the PV modules 3. They support the PV modules 3. It can also be seen in FIG. 1 that the frames 9 rest on purlins 13 in the area of the central tube 5. The purlins 13 are short metal profiles that serve as supports for the frames 9 of the PV modules 3 in the area of the central tube. The purlins 13 are connected to the top of the central tube.

The frame 9 can be screwed to the purlins 13. It is also possible to connect the frame 9 of the modules to the purlins 13 via rivets or in some other way. The struts 11 are connected at one end to the central tube 5 on its underside; for example by a screw or rivet connection. The opposite end of the struts 11 is also connected to the frame 9 of the PV module 3 by screws or rivets. For the rigidity and stability of the construction according to the invention, it is important that the fastening straps of the frame 9 on the purlins 13 on the one hand and the point at which the struts 11 support the frame 9 have the greatest possible distance A from one another. In addition, an angle 15 between the struts 11 and the frame 9 should be as large as possible. Then the mechanical load on both the frame 9 and the struts 11 is minimized with the same use of material.

A linear drive is arranged on the support 7.2. A rotary lock according to the invention is arranged on the support 7.3. This twist lock is explained in detail below with reference to FIGS. 11 to 14.

FIG. 2 shows the central tube 5 with the purlins 13, a strut 11 and a PV module 3 with a frame 9. The fact that a large number of components have been omitted compared with FIG. 1 improves the

Clarity. The left part of the central tube 5 in FIG. 2 shows that four fastening tabs 19 are arranged at regular intervals. These four fastening straps are in one plane. A normal vector of this plane runs parallel to a longitudinal axis of the central tube 5.

At the right end of the central tube 5, the four fastening tabs 19 can also be seen. A purlin 13 is screwed onto the two upper fastening straps. The two lower fastening tabs in FIG. 2 serve as abutments for the struts 11. In the left part of FIG. 2 it can be seen that the fastening tabs can be designed as bent sheet metal parts. They can be connected to the central tube 5, for example, by welding, chinches or rivets.

The distances between the fastening tabs 19 in the longitudinal direction of the central tube 5 are matched to the width of the PV modules 3. As a result, two adjacent PV modules 3 can be fastened to a purlin 13. It is also possible to support neighboring PV modules 11 with a strut 112. This cannot be seen in FIG. 2 because only one PV module 3 has been shown.

FIG. 3 shows a front view of a PV system 1 according to the invention. The same components as in FIG. 2 are visible. As can be clearly seen from FIG. 3, the PV system is constructed symmetrically with respect to the central tube 5, so that the weight forces of the PV modules 3 cancel each other out. The shear forces of the struts 11 on the central tube 5 also cancel each other out. In FIG. 3, a bearing 21 is visible below the central tube 5. This bearing 21 forms the axis of rotation or pivoting of the central tube 5 and the components arranged on it; especially the PV modules 3.

The cross section of the central tube 5 according to the invention is shown in FIG. The cross section of the central tube 5 is symmetrical with respect to an axis 23 and an axis 25. A height H of the central tube 5 is greater than a width B of the central tube 5. As a result, the central tube 5 can in addition to the bending moments resulting from the weight of the PV modules absorb the wind-induced torque. This is achieved by the enlargement H compared to the width B. The width B is ultimately largely determined by the torques to be transmitted. By suitably coordinating the H / B ratio, it is possible to keep the material stress at various points on the central tube 5 at a high level and to equalize it. As a result, a material-saving and lightweight construction is achieved without impairing the service life and stability of the construction. In FIG. 4, in addition to the width B and the height H of the central tube 5, an upper side 27, an underside 29 and side walls 31 are provided with reference symbols. Top 27 and bottom 29 have the same dimensions.

The same also applies to the side walls 31. This results results from the symmetry of the cross-section with respect to axes 23 and 25.

Intermediate surfaces 33 (here at an angle of 45 °) are arranged between the top 27 and the side walls 31 or the bottom 29 and the side walls 31, so that the cross section of the central tube 5 is composed of eight surfaces and, accordingly, eight corners.

In the part on the right in FIG. 4, a cross section through the central tube 5 according to the invention is shown in a plane in which four fastening tabs 19 are present. The fastening tabs 19 can be designed as multiple folded sheet metal profiles with a U-shaped cross-section when viewed from the side of the central tube (see FIG. 12 in this regard). As a result of the fastening tabs 19 shown as an example, the octagonal cross-sectional profile of the central tube 5 becomes a "rectangle" in the plane shown.

The fastening tabs 19 have screw holes, which are shown by dash-dotted lines. In the area of the upper side 27, the purlin 13 shown in FIG. 2 is screwed on with the aid of the fastening straps 19 or their screw holes.

The struts 11, which support the PV modules 3 on the frame 9, are screwed to the fastening tabs 19 of the underside 29 (see also FIGS their description). Further details on this are shown and explained below with reference to FIGS. 17 ff.

In order to enlarge the angle 15 (see FIG. 3) between the frame 9 and the struts 11 and thereby reduce the load on these components, it can be advantageous to arrange an intermediate element 35 on the underside 29 of the central tube. This intermediate element 35 can be a square tube. It is screwed onto the lower fastening tabs 19. Screw holes are provided on its underside 36 in order to attach a strut 11. As a result, the load on the struts 11 and the frame 9 can be reduced in a targeted manner without the central tube 5 having to be changed in terms of its geometry.

Using FIGS. 5 and 6, variants of the connection according to the invention of two segments of the central tube 5 with a sleeve are explained. The segments of the central tube 5 are denoted by 5.1, 5.2 and 5.3 in FIGS. 6 and 7.

The connection according to the invention between the segments 5.1 and 5.2 can be realized with the aid of a first embodiment of a sleeve 37 according to the invention. The sleeve 37 is pushed into the interior of the segments 5.1 and 5.2. This means that the sleeve 37 has an outer contour which corresponds to the inner contour of the central tube 5. In FIG. 4, the inner contour is denoted by the reference symbol 39. The connection between segments 5.2 and 5.3 takes place via a sleeve 43 which is pushed over the outside of segments 5.2 and 5.3, respectively. This means that the inner contour of the sleeve 43 corresponds to the outer contour 41 (see FIG. 4) of the central tube 5 or its segments 5.2, 5.3.

The overlap of the sleeves 37 or 43 and the segments 5.1, 5.2 and 5.3 has been provided with the reference symbol 45 in FIGS. 5 and 6.

A sliding fit or a slight clearance fit is provided between the sleeves 37, 43 and the segments 5.1 to 5.3 in order to make it easy to assemble the sleeves 37, 43 on site. So that the transmission according to the invention of bending and torque between the segments 5.1 and 5.2 or 5.2 and 5.3 can take place with the help of the sleeves 37, 43, the overlap 45 should be selected to be sufficiently large. Based on the main dimensions H, B of segments 5.1, 5.25.3 and the static and dynamic loads to which it is exposed during operation, the required overlap 45 can be determined for each application.

In FIG. 6, the connection between the sleeve 37 and the segment 5.2 of FIG. 6 is shown in somewhat more detail. In this illustration, a side wall 31 and two intermediate surfaces 33 of the segment 5.2 are visible.

The sleeve 37 has on its outside of the inner contour 39 of the segment 5.2 corresponding side walls and Interfaces on. These are not provided with a reference number in FIG. The overlap 45 can also be clearly seen in FIG. FIG. 7 is an example of how the connection according to the invention of segments of the central pipe 5 with a sleeve 37 at the highly stressed points of the central pipe 5 can reduce the local stresses and stresses in the central pipe 5 or the sleeves 37. FIG. 7 shows that the sleeve 37 pushed into the segment 5.2 increases the wall thickness. According to the invention it is provided that the plug connection with the sleeve 37 is provided at the locations of the central tube 5 where the highest loads occur on the central tube 5 during operation. ^{The stress [N / mm 2} ] decreases due to the local increase in wall thickness.

A plurality of intermediate pieces 53 are arranged on the sleeve 37 shown in FIG. The intermediate pieces 53 are designed in such a way that their outer contour corresponds to the inner contour 41 of the central tube 5. As a result, as can be seen from the left-hand part of FIG. 7, the contact area between the inner contour of the central tube 5 and the sleeve 37 is reduced.

In spite of this, the transmission of bending moments and torques is just as good in this embodiment as the sleeves 37, 43 described with reference to FIGS. 5 and 6. To prevent axial displacement of the segment 5.2 and the sleeve 37, a locking screw 55 is provided, which is inserted through the segment 5.2 and the sleeve 37 and then screwed. A corresponding screw connection is of course also provided on the other end of the sleeve 37, but not shown in the figures.

The actuating force to be applied by the linear drive can be predetermined structurally via the length of the lever 49. In principle, the longer the lever 49, the lower the actuating forces. However, this also increases the travel range.

In the figure 8 a further embodiment of a sleeve 37 according to the invention is shown. A flange 47 is welded to the sleeve 37, which serves to convert the adjusting movements of a linear drive (not shown in FIG. 8) into a rotary movement of the central tube 5. As can be seen from FIG. 8, a lever arm 49 with a receiving bore 51 is formed on the flange 47. One end of a linear drive or a locking rod of a rotary lock 17 can be fastened to the receiving bore 51.

An exemplary embodiment of a form-fitting connection according to the invention between two segments 5.1 and 5.4 of a central tube 5 is illustrated and explained with the aid of FIGS. In Figures 9 and 10 is another

Exemplary embodiment of a form-fitting connection according to the invention of two segments 5.1 and 5.4 of a central tube 5 is shown. In this embodiment there is no sleeve. The main dimensions H, B of the segments 5.1 and 5.4 differ slightly, so that the segment 5.4 on the right in FIG. 9 can be pushed into the segment 5.1 on the left in FIG. 9 without play or with little play. The segments 5.1 and 5.4 have a cross section as shown and explained, for example, with reference to FIGS. 4 to 6.

Because the two segments 5.1 and 5.4 are pushed directly into one another, bending moments and torques can be transmitted directly via this form-fitting connection. A socket in the actual sense is not required for this. The overlap 45 is selected in accordance with the requirements in each individual case. As a result, the torques and bending moments occurring there can be reliably transmitted at the highly stressed points, in particular the bearing points of the central tube on the pylons.

If a torque is to be introduced into the central tube 5 at this point, a lever 49 can be connected there to the central tube 5 with the aid of a shell-like fastening element 61.

FIG. 10 shows a side view of the connecting element 61 with the lever 49. at In this exemplary embodiment, the connecting element 61 has a U-shaped shell, the inner contour of which corresponds to the outer contour of the segment 5.1. It can be pushed onto the segment 5.1 of the central tube 5 from below, for example. This creates a form-fitting

Torque transmission between the lever 49 and the central tube 5 allows.

In order to stiffen the connecting element 61, a flange 47 is formed which surrounds the fastening element 61 and merges into the lever 49.

As can be seen from FIGS. 9 and 10, several fastening bores 63 are present on the fastening element 61. With the help of these fastening holes, the fastening element can be screwed to the segments 5.1 and 5.4.

The fastening bores 63 are preferably arranged opposite one another on the legs of the shell-shaped fastening element 61 which run parallel to one another. This makes it possible to screw the fastening element 61 to the central tube 5 with through bolts (not shown in FIGS. 9 and 10).

These screws only serve to fix the fastening element 61 on the central tube 5. They do not transmit any torque; instead, this is done according to the invention via the form fit between the shell-shaped Fastening element 61 and the central tube 5 or the segment 5.1.

A great advantage of this solution can be seen in the fact that the wall thickness of the fastening element 61 and of the lever 49 can be selected according to the loads occurring during operation. The wall thickness can be significantly greater than the wall thickness of the central tube 5. As a result, a material thickness corresponding to the loads occurring is achieved.

If one looks at FIG. 9, then the wall thickness of the central tube is greatest where the fastening element 61 is arranged. The wall thickness is made up of the wall thickness of the segments 5.4, 5.1 and the fastening element 61.

A further exemplary embodiment of a form-fitting connection according to the invention between the segments of the central tube and a sleeve 37 is shown on the basis of FIGS. In the case of the socket 37, a flange 47 is welded onto the octagonal pipe section. In this exemplary embodiment, the flange 47 is provided with a square or rectangular outer contour. Through bores are arranged at the corners of the flange 47. These are not provided with a reference number.

A lever 49 is screwed onto two of these fastening or through bores. On this lever 49, a receiving bore 51 is formed, which in turn is not one The linear actuator shown interacts in order to be able to perform a rotary movement of the central tube 5. The flange 47 of the sleeve 37 can also be used to screw a segment 5.1 of the central tube 5 to the flange 47.

A correspondingly designed segment 5.1 is shown in FIG. In this embodiment, a frame 65 with a square outer contour is attached to one end of the segment 5.1. Triangular plates 67 are arranged in the corners of the frame 65. The plates 67 are welded both to the frame 65 and to the intermediate surfaces 33 of the central tube 5.

The plates 67 have through bores 63, the drilling pattern of which corresponds to the corresponding bores in the flange 47. This makes it possible to positively connect two segments 5.1 to one another with a sleeve 37 according to FIG. 11 and to screw the end of the segments 5.1 to the flange 47 of the sleeve 37. It is also possible to weld a flange 47 to the end of the segment 5.1, as shown in FIG. This flange can be manufactured easily and inexpensively. It can also be welded to the end of segment 5.1 in a simple and reliable manner. By choosing the material thickness (e.g.

B. 8 mm) it can be easily adapted to the loads that occur. Another advantageous embodiment of the flange 47 is shown in FIG. Their description follows further below after the description of FIG. 22. In the figure 13 a support 7 is shown. A bracket 69 is attached to the support 7. The console 69 serves as an abutment for a linear actuator (not shown) which is arranged between the console 69 and the lever 49 of the central tube. By changing the length of the linear actuator, the central tube 5 is rotated.

The console 69 can be designed as a double-folded sheet metal blank. It comprises receiving bores 71 in which the linear actuator can be received.

A bearing block 73 is formed at the upper end of the support 7. The bearing block 73 is in two parts in this embodiment. It consists of two bent sheet metal pieces that are screwed to the support 7.

At the upper ends of the bearing block 53 in FIG. 13, receiving bores 75 are formed which receive a bolt which serves as a bearing axis. The two receiving bores 75 of the bracket 73 to a certain extent form a storage alley (not shown in FIG. 13). This bolt is not shown in FIG. However, it is shown in FIGS. 14, 15 and 16 and given the reference number 77.

In FIG. 14, a rotary bearing of the central tube 5 or a segment 5.1 on the bearing block 73 is shown in isometric view and partially in section. the end The two-part design of the bearing block 73 can be clearly seen in this isometric view. The bearing pin 77 is also clearly visible. In this exemplary embodiment, the bearing pin 77 is secured in the axial direction via a securing plate 79, so that it cannot unintentionally wander out of the receiving bores 71. The central tube 5 is rotatably mounted on the bearing pin 77. This can be done, for example, with the aid of a sleeve 73, as shown and explained in FIGS. 7, 8, 9 or 10. For this purpose, a receiving bore cooperating with the bearing pin 77 is made in the flange 47.

As a result, a very efficient storage is realized in a cost-effective manner. This bearing allows axial displacements, for example due to thermally induced expansions of the central tube 5.

FIG. 15 shows a section through the bearing.

FIG. 16 shows a side view of a support 7, a bearing block 73 as well as a sleeve 37 and a central tube or tube segment according to FIG. The interaction of the bearing block, bearing pin flange 47 and lever 49 can be clearly seen on the basis of these figures. The arrangements according to the invention of the fastenings of the PV modules 3 will be explained in more detail with reference to FIGS. 17, 18 and 19.

FIG. 17 shows that short purlins 13 are arranged on the fastening straps 19 on the upper side of the central tube 5. The fastening tabs 19 are not provided with reference numerals in FIG. 17 for the sake of clarity. Struts 11, which support the PV module 3 from below, are fastened to the fastening straps on the underside of the central tube 5.

In FIG. 18, the connections between the PV module 3 and the purlins 13 and the connection between the strut 11 and the frame of the PV module 3 are enlarged and shown in detail. Because the arrangement of the PV modules 3 is symmetrical with respect to the central tube 5, only one half of the arrangement is shown in FIG. In particular, only half the central tube 5 is shown with a side wall 31 and two intermediate or connecting surfaces 33.

The fastening tabs 19 are arranged on the intermediate or connecting surfaces 33. As can be seen, for example, from FIG. 12, the fastening tabs 19 have bores through which a purlin 13 can be screwed to the central tube. The purlins 13 according to the invention are relatively short. They only protrude about 30 to 50 cm (0.5x length - 0.2 m) laterally beyond the central tube 5. The purlins 13 are a support for the frame 9 of the PV module 3. This frame 9 is connected to the purlin 13 with one or more fastening screws 81. It is important to ensure that the frame 9 rests flat and flat on the purlin 13 so that only the permissible bending moment is introduced into the frame 9 and thus also into the PV module 3.

The contact surfaces on the lower connecting straps 19 are therefore preferably set somewhat obliquely so that they run in the direction of the longitudinal axis of the struts 11. This avoids bending stress occurring there. In Figure 19, the outer end of the strut 11 is shown. The strut 11 can be designed as a thin-walled tube which has a tab 83 at its ends. The tab 83 can be made of sheet metal, for example, and can be connected to the strut 11, for example by welding.

The tab 83 can also be produced by reshaping the strut 11 at its ends. The tab 83 has at least one through hole. The strut 11 is screwed to the frame 9 of the PV module with a fastening screw 85 via the through hole.

So that no bending moments are introduced into the bracket 83 and the struts 11, spacer sleeves are arranged on the fastening screw 85, which allow the bracket 83 to be tilted so that the brace 11 is not subjected to bending stress even after the fastening screw 85 has been tightened. FIG. 20 shows a section through two adjacent PV modules 3 at the level of the fastening screws 85. This also results in the tab 83 of a strut 11 being so wide that it is suitable for supporting two adjacent PV modules 3. Therefore, two through bores and two fastening screws 85 are shown in FIG.

In contrast to the exemplary embodiment explained with reference to FIG. 12, the flange 47 in the exemplary embodiment shown in FIG. 23 is part of a flange piece 87 which has the aforementioned flange 47 and a short pipe piece 89. The flange and the pipe section 89 are welded together. The cross section of the pipe section 89 corresponds to the cross section of a sleeve 37 which is pushed into the interior of the central tube 5, or a sleeve 43 which is pushed over the central tube 5 on the outside. With regard to the cross-sections of the sleeves 37 and 43, reference is made to FIGS. 4 to 6 and their description.

Several bores 91 are present in the pipe section 89. This makes it possible to screw the flange piece 87 to the central tube 5 after the tube piece 89 has been pushed into or onto one end of a segment 5.1 or 5.2 of the central tube 5. This has the advantage that the manufacture and transport of the central tubes 5 are simplified. The flange pieces 87 are only screwed to the central tubes during assembly on site. The half-shell 93 shown in FIG. 24 is based on a similar consideration. The half-shells 93 comprise a carrier plate 95, at the ends of which several fastening tabs 19 are welded. The carrier plate 95 is a sheet metal strip which is folded so that it rests on the outside of the central tube 5. Bores 97 for fastening screws (not shown) are provided at the ends of the carrier plate 95.

If two half-shells 93 are arranged opposite one another around a central tube 5, one can through the opposite bore 97

Insert the fastening screws (not shown) and screw a nut onto the end of each fastening screw. By tightening this screw connection, the half-shells 93 are fastened to the central tube 5 with a positive fit in the circumferential direction and with a frictional fit in the longitudinal direction. Here, too, the assembly only takes place on site when the PV system 1 is erected, without having to weld on the central tube 5.

List of reference symbols

I PV system 3 PV module

5 central tube 7 support

9 Frame of a PV module

II strut 13 purlin 15 angles

17 Twist lock 19 mounting bracket 21 bearing 23, 35 axis H height of the central tube B width of the central tube 27 top 29 bottom 31 side walls

33 Intermediate or connecting surface 35 Intermediate piece 37 Socket

39 Inner contour of the central tube 41 Outer contour of the central tube 43 Socket 45 Cover 47 Flange 49 Lever

51 Location hole 53 Intermediate piece 55 Screw 57 Weld seam 59 Counter plate 61 Connection element 63 Through hole 65 Frame 67 Plate 69 Bracket 71 Location hole 73 Bearing block 75 Location hole 77 Bearing pin 79 Securing plate 81 Fastening screw 83 Bracket

85 Fastening screw 87 Flange piece 89 Pipe section 91 Hole Half-shell support plate hole

Claims

1. Tracking system for a PV system comprising a central tube (5), several spaced-apart supports (7) and a rotary drive for the central tube (5), the central tube (5) being rotatably mounted on the supports (7), wherein the central tube (5) consists of several segments (5.1, 5.2,

5.3, 5.4), two adjacent segments (5.1, 5.2, 5.3, 5.4) being plugged into one another directly or indirectly via a sleeve (37, 43) to form a form-fitting plug connection, and the plug connection for transmitting torques and bending moments is suitable.

2. Tracking system for a PV system comprising a central tube (5), several spaced-apart supports (7) and a rotary drive for the central tube (5), the central tube (5) being rotatably mounted on the supports (7), wherein purlins (13) are attached to the central tube (5) in such a way that they protrude on both sides over the central tube (5), a length (L) of the purlins (13) being less than 0.5x a length (L ₃ ) of a PV module (3).

3. Tracking system according to claim 1 or 2, characterized in that the central tube (5) or the segments (5.1, 5.2, 5.3, 5.4) and the sleeves (37, 43) have a symmetrical cross-section with one or more lines of symmetry, a height (H) of the central tube (5) or the socket (37, 43) being greater than a width (B) of the central tube (5) or the socket (37, 43) .

4. Tracking system according to one of the preceding claims, characterized in that the central tube (5) or the segments (5.1, 5.2, 5.3,

5.4) and the sleeves (37, 43) have an octagonal cross-section.

5. Tracking system according to one of the preceding claims, characterized in that a plurality of fastening tabs (19) are arranged on the central tube (5) or its segments (5.1, 5.2, 5.3), that the fastening tabs (19) are arranged in one plane, and that a normal vector of this plane runs parallel to a longitudinal axis of the central tube (5).

6. Tracking system according to claim 5, characterized in that the purlins (13) are fastened to the fastening tabs (19) on an upper side (27) of the central tube (5).

7. Tracking system according to claim 5 or 6, characterized in that support struts (11) are fastened to the fastening tabs (19) on an underside (29) of the central tube (5).

8. Tracking system according to one of the preceding claims, characterized in that two rows of PV modules (3) are arranged on the central tube (5), a frame (9) of the PV modules (3) having its underside on a first End () rests on two purlins (13) and is detachably connected to the purlins (13).

9. Tracking system according to claim 7 and 8, characterized in that the frame (9) of a PV module (3) is supported in an area spaced from the first end by two struts (11) and is detachably connected to them.

10. Tracking system according to one of the preceding claims 1 and 3 to 9, characterized in that a flange (47) is welded to at least one sleeve (37, 43).

11. Tracking system according to claim 9, characterized in that the sleeve (37) in the region of the weld seam (57) between the sleeve (37, 43) and the flange (47) has at least one reinforcement plate or counter plate (59).

12. Tracking system according to one of the preceding claims 1 and 3 to 11, characterized in that a flange (47) is welded to at least one end of the segments (5.1, 5.4).

13. Tracking system according to one of claims 1 and 3 to 9, characterized in that two adjacent Segments (5.1, 5.4) are plugged directly into one another, and that a connecting element (61) with a flange (47) and / or a lever (49) is arranged in an overlapping area (45) of the segments (5.1, 5.4).

14. Tracking system according to claim 13, characterized in that the connecting element (61) has a cross-section that is open on one side, and that the connecting element (61) is pushed onto the central tube ().

15. Tracking system according to one of the preceding claims, characterized in that a flange (47) is welded to at least one sleeve (37, 43).

16. Tracking system according to one of the preceding claims, characterized in that the drive is a linear drive, that a bracket (69) is present on at least one support (7), and that the linear drive between the bracket (69) and one on the flange (47) formed or on the flange (47) attached lever (49) is arranged.

17. Tracking system according to one of the preceding claims, characterized in that it comprises a flange piece (87) which consists of a flange (47) and a pipe section (89), and that the pipe section (89) is inserted into one end of a central pipe (5 ) or pushed onto the end of a central tube (5) and screwed to it.

18. Tracking system according to one of the preceding

Claims, characterized in that several fastening straps (19) are arranged on a carrier plate (95), and that two carrier plates (95) are placed opposite one another around the central tube (5) and screwed together.

19. Tracking system according to claim 18, characterized in that the carrier plate (95) is a multi-folded sheet metal strip, and that the carrier plate (95) has bores (97) for fastening screws at the ends.