Stress-transmitting device for solar tracker

Abstract

The present invention relates to a device comprising a first stop (9), attached to an inner surface (5) of a bushing (3) which is driven by a torsion shaft (1) of a solar tracker; and at least one contact area (10) arranged on the first stop (9). The contact area(s) (10) are configured to make contact with respective second stops (11) which are solidly attached to a clamp (7), which is attached to a foundation post (2) of the tracker and which externally surrounds the bushing (3), when the torsion shaft (1) is in at least one predetermined stop orientation, to transmit loads and stress produced by incident wind to the foundation post (2). The device allows wind loads to be transmitted from the torsion shaft (1) to the foundation through the foundation posts (2), avoiding loading the gearbox of the solar tracker.

Description

[0001] DESCRIPTION

[0002] FORCE TRANSMITTER DEVICE FOR SOLAR TRACKER

[0003] Field of invention

[0004] The present invention is applicable in the solar energy sector, particularly in the field of solar trackers. More specifically, the invention relates to a force transmission device intended for use in a solar tracker to transmit wind forces from the torsion axis to the foundation posts of said solar tracker.

[0005] Background of the invention

[0006] The use of devices that support the load of a beam while simultaneously allowing the beam to rotate is known in the prior art. For example, in the solar installation sector, a surface has a plurality of solar panels connected by a beam that pivots on a north-south axis to orient the panels according to the sun's position. This beam is supported by a bearing that allows its rotation, mounted in a clamp fixed to a support beam, which transmits the loads to the ground. To achieve this effect, some solutions involve a closed clamp, such as patent ES2801478, while others have a split clamp, facilitating the mounting of the tracker.

[0007] Furthermore, each tracker design has a defensive position, also called the "flag position," defined by a predetermined angle formed by the horizontal wind direction and the orientation of the tracker's panels. In a rigid structure, the horizontal position has the least exposure to wind and, therefore, should bear the least amount of load. However, in reality, solar trackers are flexible structures, so the horizontal position is the one that generates the greatest aeroelastic instabilities. Conversely, the most vertical position is the most stable, even at the cost of transmitting greater loads to the ground.

[0008] The vast majority of solar trackers consist of a central actuator and a linear array of torsion beams to which the panels are attached. The longer the beam array, the more competitive the tracker becomes, as it allows the cost of the electronics and central actuator to be spread across a larger number of photovoltaic panels.

[0009] In the aforementioned case of defense positions close to the vertical that are aeroelastically more stable, at the cost of transmitting greater forces to the ground, solutions are sought where the torsion caused by the wind is not transmitted to the central actuator but to each foundation post.

[0010] Summary description of the invention

[0011] The present invention overcomes the aforementioned drawbacks by means of a force-transmitting device for a solar tracker, according to independent claim 1. Optional advantageous embodiments are described in the dependent claims and in the description of an exemplary embodiment. In particular, the invention also relates to a solar tracker that includes said force-transmitting device.

[0012] Instead of the conventional transmission of forces and energy associated with incident wind from the torsion shaft, through a gearbox acting as a fixed support, to the foundation posts and finally to the ground, the device of the invention causes this transfer of forces and energy directly from the torsion shaft to the foundation posts, with little or no intervention from the gearbox, and then to the ground. This transmission of forces to each foundation post is achieved by means of a stop that prevents the direct involvement of the bushing, which is generally made of plastic, making it fragile and potentially unreliable under impact, thus losing the required durability.Thus, the solar tracker can include one or more gearboxes, mounted on the corresponding foundation posts, so that they do not need to function as an embedded structure to receive loads, mainly wind or rotation loads, from the torsion axis.

[0013] The main advantage of the proposed solution is that it allows for a tracker defense strategy against high winds by positioning the tracker as vertically as possible, that is, at the maximum permissible tracker rotation angle, for example, 55°. In this position, the structure is aeroelastically more stable against incident winds. This also allows for optimization of the torsion axis dimensions, permitting longer trackers if the torsion axis dimensions remain the same, or smaller torsion axes for a given tracker length. This advantage is particularly important considering that aeroelastic instability effects are more pronounced in longer trackers because the loads and stresses travel a greater distance to reach the ground.

[0014] Brief description of the figures

[0015] The above and other advantages and features will be more fully understood from the following detailed description of an example embodiment, with reference to the following figures, which should be considered in an illustrative and not limiting manner.

[0016] Figure 1 shows a perspective view of the stress-transmitting device of the present invention.

[0017] Figure 2 shows an exploded perspective view of the stress-transmitting device of Figure 1 mounted on a solar tracker.

[0018] List of references

[0019] 1 Torsion shaft 2 Foundation post

[0020] 3 Bushing

[0021] 4 Hole

[0022] 5 Interior surface

[0023] 6 Exterior surface

[0024] 7. Closing element

[0025] 8 Pieces

[0026] 9 First limit

[0027] 10 Contact Zone

[0028] 11 Second limit

[0029] 12 Slits

[0030] 13 Wing

[0031] 14 Soul

[0032] 15 Angular projections

[0033] 16 Offspring

[0034] 17 Nut

[0035] 18 Washer

[0036] 19 Cradle

[0037] 20 Profile

[0038] Detailed description of the invention

[0039] A detailed description of a preferred embodiment of the force transmitter device for a solar tracker, the subject of the present invention, is then provided with the help of the attached figures 1-2 referred to above.

[0040] The solar tracker to which the device of the invention is applicable comprises a torsion shaft (1), which is supported on foundation posts (2). The tracker also includes, as is conventional, a drive (not shown), mounted on one of the foundation posts (2), for actuating a tracking rotation on the torsion shaft (1). It is possible to include several drives, each mounted on its corresponding foundation post (2), depending on the size of the tracker. The tracker further includes a bushing (3) with a through-hole (4), intended to house and surround the torsion shaft (1), and the hole (4) defines an inner surface (5) in the bushing (3) that secures the torsion shaft (1) so that the torsion shaft (1) drives the bushing (3) by means of the tracking rotation.The inner surface (5) has a shape adapted to the configuration of the torsion shaft (1) and, in the example shown, is square, although it can also be other shapes, such as octagonal or hexagonal, for example. Furthermore, the bushing (3) also has an outer surface (6).

[0041] The torsion axis (1), together with the bushing (3), is supported on the foundation post (2) by means of support elements that also surround the bushing (3) and, therefore, the torsion axis (1). To surround the bushing (3), the support elements are configured accordingly, according to various possibilities. In a less preferred example, the support elements comprise a single piece that completely surrounds the bushing (3). However, in the more preferred example, represented by Figures 1-2, the support elements comprise: a cradle (19), for example, made of stamped metal, which does not completely surround the bushing (3); and, optionally, an inverted U-shaped profile (20) inserted between the foundation post (2) and the cradle (19), allowing variable height and, optionally, tilt adjustment.According to the example shown, to surround the upper part of the bushing (3) there is additionally a closing element (7), preferably metallic, connected to the cradle (19), for example, through a screw joint comprising: screw stems (16), to be housed in holes (21) of the cradle (19); as well as, optionally, respective nuts (17) and / or washers (18).

[0042] The bushing (3) is preferably made of a plastic material. The outer surface (6) of the bushing (3) can have various shapes, such as cylindrical, as shown in the figures, or spherical, corresponding to the support means—in particular, the cradle (19)—and, where applicable, the locking element (7). It is preferred that the bushing (3) be made in two or more pieces (8), preferably in two pieces (8), to facilitate the mounting of the torsion shaft (1) within the bushing (3).

[0043] Fixed to the inner surface (5) of the bushing (3) and thus integral with the torsion shaft (1), is a first stop (9), provided with at least one contact area (10) for making contact with a respective second stop (11) integral with the support means, for example, the locking element (7), when the torsion shaft (1) is in at least one predetermined stop orientation during tracking rotation, in order to transmit to the foundation post (2) loads and stresses produced by incident wind, for example, in the defensive position. Preferably, two stop orientations are defined, corresponding to the maximum rotation permitted for the torsion shaft (1) by design in each direction. Preferably, the first stop (9) is arranged on a lower part of the bushing (3).The first stop (9) and the second stop (11) have the purpose of supporting and transferring forces towards the foundation posts (2) involving the reducers as little as possible, so they can be made of impact-resistant material, for example, a metallic material suitable for screws, or of an impact-absorbing material, for example, a suitable elastomer, either alone or covering a rigid element.

[0044] The second stop (11) can be a protruding element of the support means, such as, as shown in the figures, of the cradle (19). For example, the second stop (11) can be a component of the bolted joint described above, such as the head or shank (16) of the bolt, the nut (17), or the washer (18), whether metallic or elastomeric, among others, of said bolted joint used to close the locking element (7) around the bushing (3), or even a rubber or plastic pad. In the example shown, the first stop (9) has two contact zones (10), corresponding to two second stops (11), to transmit loads in each of the two defined stop orientations.

[0045] According to the embodiment shown in Figure 1, the inner surface (5) has grooves (12) to accommodate the first stop (9). The first stop (9) may be configured as at least a U-shaped body with two wing-like plates (13) connected by a web-like plate (14), where the contact areas (10) are located on one of the wings (13) of said body. In the embodiment illustrated in the figures, the first stop (9) comprises a single body mounted on a lower part of the bushing (3), although optionally, a body mounted on the upper part of the bushing (3) may also be provided. Additionally, to improve retention, the first stop (9) may also include angled projections (15) extending from the web (14) to engage laterally with the inner surface (5) of the bushing (3).If two bodies are available, one at the top and one at the bottom, the respective angles (15) can be in mutual contact, at an intermediate dimension of the bushing (3), or even the two bodies, together with the angles (15), can form a single piece in the form of a ring to completely embrace the torsion shaft (1).

Claims

CLAIMS 1. Force transmitter device for solar tracker, characterized in that it comprises: - a first stop (9), intended to be fixed to an inner surface (5) of a bushing (3) that surrounds, and is driven by, a torsion shaft (1) of a solar tracker; and - at least one contact zone (10) disposed on the first stop (9); wherein the contact zone or zones (10) are configured, when the torsion axis (1) is in at least one predetermined stop orientation, to make contact with respective second stops (11) which are integral with support means intended to jointly support the torsion axis (1) and the bushing (3) on a foundation post (2) of the follower, the support means being intended to surround the bushing (3) and the torsion axis (1) externally, the contact of the contact zone or zones (10) being for transmitting to the foundation post (2) loads and stresses produced by incident wind. 2.- Force transmitter device for solar tracker according to claim 1, wherein the first stop (9) is metallic. 3.- Force transmitting device for solar tracker according to any of claims 1-2, wherein the first stop (9) is arranged in a lower part of the bushing (3). 4.- Force transmitting device for solar tracker according to any of claims 1-3, wherein the first stop (9) has two contact zones (10). 5.- Force transmitting device for solar tracker according to any of claims 1-4, wherein the first stop (9) is configured as at least one U-shaped body, with two wing-like plates (13) connected by a web-like plate (14), wherein the contact zone or zones (10) are located on one of the wings (13). g 6.- Force transmitting device for solar tracker according to claim 5, wherein the first stop (9) comprises only a U-shaped body, which is located at the top or bottom of the bushing (3). 7.- Force transmitting device for solar tracker according to claim 5, wherein the first stop (9) comprises two U-shaped bodies, one located at the top and the other at the bottom, of the bushing (3). 8.- Force transmitter device for solar tracker according to claim 7, wherein the two U-shaped bodies constitute a single piece that completely embraces the torsion shaft (1). 9.- Force transmitting device for solar tracker according to any of claims 1-8, wherein the first stop (9) further includes angular projections (15) to be housed laterally in an inner surface (5) of the bushing (3). 10.- Force transmitting device for solar tracker according to claims 7 and 9 jointly, wherein the angles (15) of each of the U-shaped bodies meet the angles of the other U-shaped body.

11. Solar tracker comprising: - a torsion axis (1), supported on foundation posts (2); - a drive, mounted on one of the foundation posts (2), for actuating a tracking slew on the torsion axis (1); - a bushing (3) with a through-hole (4), intended to house and surround the torsion shaft (1), wherein the hole (4) defines in the bushing (3) an inner surface (5) that secures the torsion shaft (1) such that the torsion shaft (1) drives the bushing (3) by means of the following rotation; and - support means, surrounding the bushing (3) and the torsion shaft (1), and supporting the torsion shaft (1) and the bushing (3) on one of the foundation posts (2); the solar tracker being characterized in that it further comprises the force transmitting device described in any of claims 1-10. 12.- Solar tracker according to claim 11, wherein the inner surface (5) of the bushing (3) has grooves (12) to accommodate the first stop (9).

13. Solar tracker according to any of claims 11-12, wherein the support means comprise a piece that entirely surrounds the bushing (3).

14. Solar tracker according to any of claims 11-12, wherein the support means comprise: - a cradle (19), on which the bushing (3) is supported, without completely surrounding the bushing (3); and - a closing element (7), connected superiorly to the cradle (19), to jointly surround the bushing (3).

15. Solar tracker according to any of claims 11-12, wherein the second or second stops (11) are protruding elements of the support means. 16.- Solar tracker according to claim 15, wherein the second or second stops (11) protrude from the cradle (19). 17.- Solar tracker according to any of claims 14-16, wherein the second or second stops (11) form part of a bolted joint used to close the closing element (7) around the bushing (3).

18. Solar tracker according to claim 17, wherein the second or second stops (11) are selected from: - stem (16) of the bolted joint; - head of the bolted joint; - nut (17) of the bolted joint; and - washer (18) of the bolted joint.

19. Solar tracker according to any of claims 13-15, wherein the second or second stops (11) comprise a rubber or plastic block.

20. Solar tracker according to any of claims 11-19, wherein each stop orientation corresponds to a maximum rotation allowed to the torsion axis (1) by design in one or both directions.

21. Solar tracker according to any of claims 11-20, wherein the bushing (3) is made of a plastic material.

22. Solar tracker according to any of claims 11-21, wherein the bushing (3) is manufactured in two or more pieces (8) to facilitate mounting of the torsion shaft (1) within the bushing (3). 23.- Solar tracker according to any of claims 11-22, further comprising a reducer mounted on one of the foundation posts (2), in such a way that it does not need to function as an embedment or receive loads from the torsion axis (1).

24. Solar tracker according to any of claims 11-23, wherein the support means comprise a single piece that entirely surrounds the bushing (3).

25. Solar tracker according to any of claims 11-24, wherein the bushing (3) has an outer surface (6) with a cylindrical or spherical shape, corresponding to the support means.

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