Spring balancing assembly and solar tracker including spring balancing assembly

Abstract

A solar tracker assembly is provided that includes a support column, a torque tube or torsion beam connected to the support column, a mounting mechanism attached to the torque tube or torsion beam, a drive system connected to the torque tube or torsion beam, and a spring balancing assembly connected to the torque tube or torsion beam. An example spring balancing assembly includes a bearing housing and a sleeve disposed within the bearing housing and configured to slidably mount on a torque tube or torsion beam, and one or more compressible cords that may be made of a flexible material. A compressible cord is located between the sleeve and the bearing housing and provides damping during rotational movement of the solar tracker assembly. An exemplary spring balancing assembly is provided that includes at least one top bracket and at least one bottom bracket, at least one spring, a damper, and a bracket. An example spring balancing assembly includes a bearing housing and a sleeve disposed within the bearing housing and configured to be slidably mounted on a torque tube or torsion beam.

Description

[0001] This application is a divisional application of application number 201880028588.8, filing date March 1, 2018, and invention name “Spring balance assembly and solar tracker including a spring balance assembly”.

[0002] Related applications

[0003] This application claims priority to and the benefit of U.S. Patent Application Serial No. 62 / 466,235, filed March 2, 2017, which is incorporated herein by reference in its entirety. Technical Field

[0004] The present disclosure relates to spring balancing assemblies. The present disclosure also relates to spring assemblies for balancing the rotation of solar trackers and solar cell arrays. Background Art

[0005] Solar tracking systems are used in photovoltaic and solar thermal applications to increase sunlight collection by aiming photovoltaic panels or collectors at the sun as it moves across the sky. In doing so, the tracking system includes a pivot point or bearing on which it rotates. These bearings can be placed at the center of gravity of the tracking system or can be located below the photovoltaic or collector array.

[0006] Array balancing, a technique that places the bearing housing at or near the array's center of gravity, has the benefit of reducing stress on the positioning drive because there is little or no cantilever weight to generate the moment loads inherent in the positioning system. Furthermore, balancing the mechanical system about the center of gravity also reduces or eliminates torsional deflection of the support structure, which can allow for less structural material requirements.

[0007] To balance with a pivot point located at or near the center of gravity of the tracking system, most designs must position the pivot point above the surface of the PV panel module or collector. This creates complexity in the structure, bearing the pivot point, and density inefficiencies because space must exist in the collecting surface for the bearing to reside. The space where the center of gravity bearing resides is often referred to as dead space in the system because solar energy collection is not possible in these areas of the system. When used in large PV panel solar farms or collectors, these dead spaces in the north / south length of the tracker row multiply by the required east / west spacing between trackers and result in a significant reduction in density across the entire field.

[0008] Therefore, there is a need for an improved system for balancing the rotation of a tracking system. There is also a need for an improved balancing system that eliminates dead zones in the system. There is also a need for an improved balancing system that is less complex, requires less structural material, and results in lower torsional deflection in the system. Summary of the Invention

[0009] Exemplary embodiments of the present disclosure largely mitigate the shortcomings of known balanced systems for solar trackers by incorporating spring elements in the solar tracker to counteract mechanical rotation rather than a center of gravity pivot point. This provides the advantages of keeping the pivot bearings and structure uncomplicated and requiring no dead space in the system, which yields all the benefits of a balanced structure without the loss of dead space and field density inefficiencies. These benefits include low complexity, less stress on the mechanical drive system, less structural material, and less torsional deflection of the system, as well as less stress on the bearings themselves since they are located around the circumference of the torque transmitting structural assembly. More specifically, the benefits include lower complexity of the bearings and structure relative to balanced center of gravity bearing systems plus the attributes of a balanced CG system, such as less stress on the mechanical drive system, less structural material, less torsional deflection of the system, and elimination of collector dead space to achieve high density.

[0010] An exemplary embodiment of a solar tracker assembly includes a support column, a torque tube or torsion beam connected to the support column, a mounting mechanism attached to the torque tube or torsion beam, a drive system connected to the torque tube or torsion beam, and a spring balancing assembly connected to the torque tube or torsion beam. One or more types of spring balancing assemblies may be incorporated into the solar tracker assembly to balance its rotation.

[0011] An exemplary embodiment of a spring balance assembly includes at least one top bracket and at least one bottom bracket, at least one spring, a damper, and a bracket. The spring has a first end and a second end. The first end of the spring is attached to the top bracket, and the second end of the spring is attached to the bottom bracket. The damper has a first end and a second end. The first end of the damper is attached to the top bracket, and the second end of the damper is attached to the bottom bracket, such that the damper is positioned substantially parallel to the spring. The bracket is attached to the top bracket and is sized and shaped to accommodate insertion of a torque tube or torsion beam through the bracket, allowing the spring balance assembly to be incorporated into a solar tracker.

[0012] In an exemplary embodiment, the spring is selected from the group consisting of a tension spring, an extension spring, and a leaf spring. The spring can be incorporated into a damper, a damper bracket assembly, or a bearing housing. In an exemplary embodiment, the solar tracker assembly is incorporated into a row of solar trackers, wherein the spring balance assembly includes a first spring balance assembly coupled to a torque tube or torsion beam at or near a first end of the row and coupled to a first spring, and a second spring balance assembly coupled to a torque tube or torsion beam at or near a second end of the row and coupled to a second spring.

[0013] In an exemplary embodiment, a solar tracker assembly includes a support column, a torque tube or torsion beam connected to the support column, a mounting mechanism attached to the torque tube or torsion beam, a drive system connected to the torque tube or torsion beam, and a spring connected to the torque tube or torsion beam. One or more solar modules can be mounted on the mounting mechanism. The spring can be a tension spring, an extension spring, and / or a leaf spring.

[0014] In an exemplary embodiment, the solar tracker assembly further includes a damper bracket assembly attached to the torque tube or torsion beam, and a spring is incorporated into the damper bracket assembly. In an exemplary embodiment, the solar tracker assembly further includes at least one damper attached to the torque tube or torsion beam, and a spring is incorporated into the damper. The solar tracker assembly may have at least one bearing housing that attaches the torque tube or torsion beam to the support column, and the spring may be located in the bearing housing. In an exemplary embodiment, the spring is incorporated into the bearing housing. The solar tracker assembly may also include a torque limiter assembly.

[0015] In an exemplary embodiment, the solar tracker assembly further includes a spring balancing assembly comprising at least one top bracket and at least one bottom bracket, at least one spring, a damper, and a bracket mounting device. The spring has a first end and a second end. The first end of the spring is attached to the top bracket, and the second end of the spring is attached to the bottom bracket. The damper has a first end and a second end. The first end of the damper is attached to the top bracket, and the second end of the damper is attached to the bottom bracket, such that the damper is positioned substantially parallel to the spring. A bracket is attached to the top bracket, and a torque tube or torsion beam is inserted through the bracket to connect the spring balancing assembly to the torque tube or torsion beam.

[0016] An exemplary embodiment of a solar array includes at least one row of trackers. Each row of trackers includes at least one support column, at least one torque tube or torsion beam connected to the support column, a mounting mechanism attached to the torque tube or torsion beam, a drive system connected to the torque tube or torsion beam, a first spring connected to the torque tube or torsion beam at or near a first end of the row, and a second spring connected to the torque tube or torsion beam at or near a second end of the row, where the second end is opposite the first end. One or more solar modules can be mounted on the mounting mechanism of the solar array. The springs can be tension springs, extension springs, and / or leaf springs.

[0017] In an exemplary embodiment, the solar array further includes a damper bracket assembly attached to the torque tube or torsion beam, and a spring is incorporated into the damper bracket assembly. In an exemplary embodiment, the solar array further includes at least one damper attached to the torque tube or torsion beam, and a spring is incorporated into the damper. The solar array may have at least one bearing housing that attaches the torque tube or torsion beam to the support column, and the spring may be located at the bearing housing. In an exemplary embodiment, the spring is incorporated into the bearing housing. The solar array may also include a torque limiter assembly.

[0018] A solar array can have a first spring-balancing assembly connected to a torque tube or torsion beam at or near the first end of the array and incorporating a first spring, and a second spring-balancing assembly connected to the torque tube or torsion beam at or near the second end of the array and incorporating a second spring. Each spring-balancing assembly includes at least one top bracket and at least one bottom bracket, at least one spring, a damper, and a bracket. The spring has a first end and a second end. The first end of the spring is attached to the top bracket, and the second end of the spring is attached to the bottom bracket. The damper has a first end and a second end. The first end of the damper is attached to the top bracket, and the second end of the damper is attached to the bottom bracket, such that the damper is positioned substantially parallel to the spring. The bracket is attached to the top bracket and allows the torque tube or torsion beam to be inserted through the bracket to connect the spring-balancing assembly to the torque tube or torsion beam.

[0019] In an exemplary embodiment, a spring balance assembly includes an eccentric compression sleeve configured to be slidably mounted on a torque tube or torsion beam; a shaped outer bearing housing configured to be mounted over the eccentric compression sleeve; and / or a plurality of compressible cords constructed of an elastic material. The eccentric compression sleeve and the shaped outer bearing housing can provide damping during rotational movement of the solar tracker assembly. The flexible material of the compressible cords can be rubber or another elastomer. In an exemplary embodiment, the sleeve has an octagonal inner surface with one or more substantially flat surfaces, and the bearing housing has one or more protrusions, defining one or more spaces between the substantially flat surfaces and the protrusions. The compressible cords can be disposed in the spaces between the substantially flat surfaces and the protrusions.

[0020] In an exemplary embodiment, the sleeve has an octagonal inner cross-section and a substantially circular outer cross-section with four protrusions. The bearing housing can be substantially square, and the spring balance assembly allows for rotation of the torque tube or torsion beam up to at least plus or minus 45 degrees. In an exemplary embodiment, the sleeve has an octagonal inner cross-section and a substantially triangular outer cross-section with three protrusions, and the spring balance assembly allows for rotation of the torque tube or torsion beam up to at least plus or minus 60 degrees. The outer bearing housing is one of the following: substantially square, substantially hexagonal, and substantially circular with three protrusions.

[0021] An exemplary embodiment of a spring balance assembly includes: a bearing housing having one or more protrusions; a sleeve disposed within the bearing housing such that one or more spaces are defined between the sleeve and the protrusions; and one or more compressible cords composed of an elastomeric material disposed in the spaces between the sleeve and the protrusions.

[0022] In an exemplary embodiment, a spring balance assembly includes a bearing housing and a sleeve disposed within the bearing housing and configured to be slidably mounted on a torque tube or a torsion beam. The spring balance assembly may also include at least one coil spring and a rotation stop. The sleeve may be made of an elastic material and define one or more air spaces. In an exemplary embodiment, the spring balance assembly also includes at least one rotation stop. The bearing housing may be made of an elastic material and also include at least one rotation stop.

[0023] Thus, it can be seen that a spring balancing assembly and balancing system for solar trackers and solar arrays are provided. The disclosed assembly, system, and method provide an improved balancing system that eliminates deadband, reduces complexity, requires less structural material, minimizes actuation force, and results in lower torsional deflection. These and other features and advantages will be understood upon reading the following detailed description and accompanying drawings, in which like reference numerals represent like components throughout. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above features and objects of the present disclosure will become more apparent with reference to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like elements, and wherein:

[0025] Figure 1 is a perspective view of an exemplary embodiment of a solar tracker assembly according to the present disclosure;

[0026] Figure 2A is a perspective view of an exemplary embodiment of a spring balance assembly according to the present disclosure;

[0027] Figure 2B yes Figure 2A A side view of the spring balance assembly;

[0028] Figure 3 is a side view of an exemplary embodiment of a spring balance assembly mounted on a torque tube or torsion beam according to the present disclosure;

[0029] Figure 4 is a perspective view of an exemplary embodiment of a spring balance assembly mounted on a solar tracker assembly according to the present disclosure;

[0030] Figure 5A is a perspective view of an exemplary embodiment of an extension spring balance assembly according to the present disclosure;

[0031] Figure 5B yes Figure 5A A side view of the extension spring balance assembly;

[0032] Figure 6 is a perspective view of an exemplary embodiment of an extension spring balance assembly mounted on a torque tube or torsion beam according to the present disclosure;

[0033] Figure 7 is a side view of an exemplary embodiment of an extension spring balance assembly mounted on a torque tube or torsion beam according to the present disclosure;

[0034] Figure 8 is a side view of an exemplary embodiment of an extension spring balance assembly mounted on a solar tracker assembly according to the present disclosure;

[0035] Figure 9 is a perspective view of an exemplary embodiment of an extension spring balance assembly mounted on a solar tracker assembly according to the present disclosure;

[0036] Figure 10 is a cross-sectional view of an exemplary embodiment of an integrated spring-balanced bearing assembly according to the present disclosure;

[0037] Figure 11 is a cross-sectional view of an exemplary embodiment of an integrated spring-balanced bearing assembly according to the present disclosure;

[0038] Figure 12 is a side view of an exemplary embodiment of an integrated torsion spring balance bearing assembly according to the present disclosure;

[0039] Figure 13A is a top view of an exemplary embodiment of a bearing housing of a spring balance assembly according to the present disclosure;

[0040] Figure 13B According to the present disclosure Figure 13A a side view of an exemplary embodiment of a torsion spring bearing insert;

[0041] Figure 14Ais a perspective view of an exemplary embodiment of an integrated spring-balanced bearing assembly according to the present disclosure;

[0042] Figure 14B yes Figure 14A A front cross-sectional view of an integrated spring balance bearing assembly;

[0043] Figure 14C yes Figure 14A Detailed view of the corner of the elastomer space of the integrated spring balance bearing assembly;

[0044] Figure 15A is a perspective view of an exemplary embodiment of a bearing housing of a spring balance assembly according to the present disclosure;

[0045] Figure 15B yes Figure 15A A front view of the bearing housing;

[0046] Figure 15C yes Figure 15A A side view of the bearing housing;

[0047] Figure 15D yes Figure 14A A top view of a sleeve of a bearing assembly;

[0048] Figure 16A is a perspective view of an exemplary embodiment of a sleeve of a spring balance assembly according to the present disclosure;

[0049] Figure 16B yes Figure 16A A front cross-sectional view of the sleeve;

[0050] Figure 17A is a perspective view of an exemplary embodiment of a compressible cord of a spring balance assembly according to the present disclosure;

[0051] Figure 17B yes Figure 17A A front cross-sectional view of a compressible cord;

[0052] Figure 17C yes Figure 17A A side view of a compressible cord;

[0053] Figure 17D yes Figure 17A A top view of a compressible cord;

[0054] Figure 18A is a front cross-sectional view of an exemplary embodiment of a spring balance assembly without a compressible cord according to the present disclosure;

[0055] Figure 18B yes Figure 18A A front cross-sectional view of a spring balance assembly;

[0056] Figure 18C It is rotating Figure 18A A front cross-sectional view of a spring balance assembly;

[0057] Figure 19 is a perspective view of an exemplary embodiment of a spring balance assembly according to the present disclosure;

[0058] Figure 20A is a front cross-sectional view of an exemplary embodiment of a spring balance assembly according to the present disclosure;

[0059] Figure 20B It is rotated 30 degrees Figure 20A A front cross-sectional view of a spring balance assembly;

[0060] Figure 20C It is rotated 52 degrees. Figure 20A A front cross-sectional view of a spring balance assembly;

[0061] Figure 21 is a perspective view of an exemplary embodiment of a spring balance assembly mounted on a torque tube or torsion beam according to the present disclosure;

[0062] Figure 22 is a perspective view of an exemplary embodiment of a spring balance assembly mounted on a solar tracker assembly according to the present disclosure;

[0063] Figure 23A is a front cross-sectional view of an exemplary embodiment of a spring balance assembly according to the present disclosure;

[0064] Figure 23B It is rotating Figure 23A A front cross-sectional view of a spring balance assembly;

[0065] Figure 23C It is rotating Figure 23A A front cross-sectional view of a spring balance assembly;

[0066] Figure 24 is a perspective view of an exemplary embodiment of a spring balance assembly mounted on a torque tube or torsion beam according to the present disclosure; and

[0067] Figure 25 is a perspective view of an exemplary embodiment of a spring balance assembly mounted on a solar tracker assembly according to the present disclosure. DETAILED DESCRIPTION

[0068] In the following paragraphs, embodiments will be described in detail by way of example with reference to the accompanying drawings, which are not drawn to scale and in which the parts shown are not necessarily drawn in proportion to each other. Throughout the specification, the embodiments and examples shown should be considered as examples rather than limitations of the present disclosure. As used herein, "the present disclosure" refers to any one embodiment described herein, and any equivalents. In addition, reference to various aspects of the present disclosure throughout this document does not mean that all claimed embodiments or methods must include the cited aspects.

[0069] A solar tracker comprising one or more spring balance assemblies will now be described. The spring balance assemblies described herein are designed to allow a large degree of rotation and to counteract the cantilever weight of the collector mounted on a torque tube or torsion beam assembly. Figure 1 As shown, the exemplary solar tracker assembly 12 includes at least one support column 32. The support column 32 can be of any shape and constructed of any material, as long as it is capable of supporting the PV module or collector mounted thereon. The exemplary embodiment of the solar tracker assembly 12 includes two spaced-apart support columns 32. A torque tube or torsion beam 34 or other tracker structure is connected to the support columns. More specifically, the torsion beam 34 bridges the two support columns and can be attached to the support columns 32 via a bearing housing 36 and a bearing housing assembly comprising any suitable fasteners.

[0070] The torque tube or torsion beam 34, comprising a plurality of connected beams, can be of any shape or configuration suitable for supporting a mount or other mounting mechanism, and in exemplary embodiments, has a circular, square, or hexagonal cross-section. It should be noted that the torque tube or torsion beam 34 can be of any cross-sectional shape, including but not limited to circular, round, oval, square, rectangular, triangular, pentagonal, hexagonal, and octagonal. In systems with cantilevered weights, the cantilevered load torque varies as the system rotates.

[0071] A pivot axis 40 extends through the torque tube or torsion beam 34, which can pivot or rotate about the pivot axis 40. A solar module 42 can be mounted to the solar tracker 12, mounted to the torque tube or torsion beam 34 using a clamp or mounting bracket 35, or mounted to a mounting frame via a module mounting bracket assembly or other mounting device. It should be noted that a solar tracker can utilize more than one torque tube or torsion beam in a dual-beam or multi-beam torsion configuration. In such an embodiment, the tracker would have two or more torsion beams extending along its length. A row of multiple trackers can have two or more torsion beams extending along the length of the row.

[0072] A mounting bracket (not shown) is attached to the torque tube or torsion beam 34. In the exemplary embodiment, the mounting bracket includes a front frame support and a rear frame support (not shown). The front frame support is disposed on a first side of the torque tube or torsion beam, and the rear frame support is disposed on a second, opposite side of the torque tube or torsion beam.

[0073] The solar tracker 12 can have a gear-driven mechanical system that includes a rack and pinion 14. The mechanical system can also include a gear drive system 16 that includes a torque limiter 18, such as a torque-limiting clutch. An electric motor 15 can be provided to drive the gear drive system 16, which in turn directly rotates a torsion beam or torque tube 34, or drives the rack and pinion 14, which in turn drives the torque tube or torsion beam 34 or another module mounted on the beam structure. The rack and pinion 14 can be a spur gear rack or a D-ring chain drive secured to the tracker's rotatable torque tube or torsion beam. Thus, when driven by the gear drive system, the tracker rotates. A second, third, and other mechanical units similar to the tracking assembly 12 can be connected to the drive shaft 25 via separate and similar worm assemblies. This can be repeated for multiple mechanical units in the gear-driven mechanical system.

[0074] The exemplary solar tracker assembly 12 may also include one or more dampers 58 incorporated into or near the gear rack to control the release of torsional forces and slow the movement of the solar tracker assembly. The dampers 58 can serve dual functions as stops at the array ends, or they can be located anywhere to help adjust the torsional release reaction speed and resist hinge moment loads. In the exemplary embodiment, a spring is integrated into at least one of the dampers. Additional brackets can be provided that allow the damper 58 to be connected between the torque tube 34 and support column 32 of the tracker 12. The damper 58 can be incorporated into the gear drive to control the rate of tracker rotation during an over-torque release event. When torsion is released by allowing the system to rotate, the rate at which the array is allowed to move can be controlled by the sliding friction of the clutch, an external damper, or both. The spring can be incorporated into one or more of the damper brackets.

[0075] Reference Figure 2A-Figure 9 , an exemplary embodiment of the spring balance assembly 10 and 10a will now be described. The exemplary embodiment of the spring balance assembly includes a top bracket 62, a bottom bracket 64, a damper 66, a bracket 68, and a spring 70, which may be a tension spring, an extension spring, a leaf spring, or any other suitable type of spring. The spring 70 is located between the top bracket 62 and the bottom bracket 64. More specifically, a first end of the spring 70 is directly or indirectly attached to the top bracket, and a second end of the spring 70 is directly or indirectly attached to the bottom bracket 64. As shown in FIG. Figure 2A and Figure 2BAs best shown, spring seat 72 can be used to connect spring 70 to top bracket 62 and bottom bracket 64. Alternatively, as shown in FIG. Figure 5A and Figure 5B As best shown, the spring 70 of the spring balance assembly 10 a may be directly connected to the top bracket 62 and the bottom bracket 64 .

[0076] In the exemplary embodiment, damper 66 is positioned substantially parallel to spring 70. More specifically, a first end of damper 66 is attached to top bracket 62, and a second end of damper 66 is attached to bottom bracket 62. In the exemplary embodiment, a bracket 68 is attached to top bracket 62 and is sized and shaped to allow the torque tube or torsion beam 34 to be inserted through the bracket. This configuration of brackets provides for quick and easy attachment of the torque tube or torsion beam and incorporation of the spring balance assembly into the solar tracker. It should be noted that more than one bracket 68 can be used, and the exemplary embodiment employs two or more brackets 68 for mounting the spring balance assembly to the torque tube or torsion beam 34. The balance spring and damper can also be mounted to the same or different locations on the support column (not shown) via separate brackets with similar effect.

[0077] like Figure 3-Figure 4 and Figure 6-Figure 9 As shown, the extension spring balance assembly 10 or 10a can be incorporated into a solar tracker by connecting the spring balance assembly to the tracker's torque tube or torsion beam. As described above, the spring balance assembly 10 is connected to the solar tracker via one or more brackets 68 on the assembly's top frame. More specifically, because the bracket is sized and shaped to fit over the torque tube or torsion beam, it can be slid onto the torque tube or torsion beam (or a tube or beam inserted through an opening in the bracket) to attach the spring balance assembly to the tracker. Figure 4 、 Figure 6 and Figure 9 As best shown, the spring balance assembly can also be secured to the support column at one or more locations using lower brackets 74. More specifically, the top frame can include pins, threaded fasteners, or other types of fasteners to attach it to the top portion of the support column, and / or the bottom frame can have one or more additional lower brackets 74 that fit around the support member and attach it to the support column at a location at or near the bottom of the support column.

[0078] In an exemplary embodiment, the balancing assembly 10 or 10a can be incorporated into a solar array comprising one or more rows of solar trackers. The solar array can include individual motorized trackers without mechanical connections between the rows. The array can include multiple rows of solar trackers, comprised of multiple connected rows of solar trackers. More specifically, multiple solar trackers can be mechanically connected in a large array configuration so that they can operate in unison driven by a single motor and tracker controller. In an exemplary embodiment, one spring is connected to a torque tube or torsion beam at or near a first end of a tracker row, and another spring is connected to a torque tube or torsion beam at or near a second end of the row. As described above, each spring can be incorporated into a spring balancing assembly or into a damper or bearing housing assembly.

[0079] Exemplary embodiments include a configuration in which two tension springs are positioned toward the ends of the tracker row. The tension springs can be incorporated into the damper bracket assembly or provided separately from the dampers via a separate bracket. Exemplary embodiments include a configuration in which two compression tension springs are positioned toward the ends of the tracker row. The compression tension springs can be incorporated into the damper bracket assembly or provided separately from the dampers via a separate bracket. Exemplary embodiments include a configuration in which two leaf springs are positioned toward the ends of the tracker row (not shown). The leaf springs can be incorporated into the damper bracket assembly or provided separately from the dampers via a separate bracket. In exemplary embodiments, smaller tension rods, tension springs, or leaf springs can be located at each bearing housing. The springs can also be integrated into the bearing housing's stop. Exemplary trackers can include torsion spring pivot points that are integral with the bearing housing and / or torsion spring pivot points that are not integral with the bearing housing but have balanced motion.

[0080] Solar trackers incorporating the aforementioned non-elastic spring balance assembly embodiments typically have an inherent damping mechanism. Dampers and their use in solar trackers are described in detail in U.S. Patent No. 9,581,678, issued on February 28, 2017, the entire contents of which are incorporated herein by reference. Figure 1As best shown, an exemplary solar tracker can include a damper incorporated on or near the gear rack to control the release of torsional forces and slow the motion of the solar tracker assembly. The damper can be incorporated into the gear drive to control the rate at which the tracker rotates during an over-torque event. The maximum angle stop can then be resisted not only by the gear rack, but also by a damper at the gear rack, or by a stop at the end of the solar tracker 12 row, thereby sharing the torsional load of the gear rack 60 and distributing it across multiple points on the torque tube 34. The damper 58 can serve dual purposes as a stop at the end of the array, or the damper can be designed to be placed at any location to help adjust the torsional release reaction speed and resist hinge moment loads.

[0081] Now turn Figure 10 An exemplary embodiment of an integrated spring balance assembly employing a discrete coil spring and a rotation stop will now be described. The spring balance assembly 110 does not provide inherent damping and may require additional dampers to control the speed of movement or oscillation. The spring balance assembly 110, shown in cross-section, has a housing 162 comprising an upper circular portion 166 that slides onto a torque tube or torsion beam of a solar tracker, and a lower portion 168. An inner layer 174 of aluminum or other suitable structural material is disposed within the top portion 166 of the housing 162, with a circular layer 167 of polymer bearing material disposed between the top portion 166 and the inner layer 174. The inner surface of the inner layer 174 is sized and shaped to fit over the torque tube or torsion beam of the solar tracker. In the exemplary embodiment, the inner surface of the inner layer 174 has an octagonal cross-section, and the outer surface has a substantially circular cross-section.

[0082] The lower portion 168 of the housing 162 includes two coil springs 170, a stop 164, and a bottom surface for engaging a mounting bolt 172 or other fastening mechanism. More specifically, the stop 164 is located in the center of the spring balance assembly 110, directly below the inner layer 174. The stop 164 is flanked on each side by a coil spring 170, one coil spring 170 adjacent to the right side of the stop 164 and the other coil spring 170 adjacent to the left side of the stop 164. This dual-spring and stop design of the spring balance assembly 110 advantageously limits rotation of the torque tube or torsion beam along its rotation angle 176 in two ways. Each coil spring 170 provides resistance to rotation, and depending on the direction of rotation, the right or left coil spring can compress downward. Furthermore, as the torque tube or torsion beam rotates, the stop 164 impacts the side of the lower portion 168 of the housing 162 of the spring balance assembly 110, limiting rotation.

[0083] Figure 11An exemplary embodiment of a spring balance assembly with a radially elastic sleeve is shown. Due to the lack of spring hysteresis in the elastomer, this embodiment can also provide inherent damping. Spring balance assembly 210 includes a housing 262 having a stop 264 as part of the internal structure of the housing itself. In the exemplary embodiment, housing 262 is made of aluminum, cast iron, or other suitable structural materials. Disposed within housing 262 is a substantially circular intermediate layer 270 composed of an elastic polymer material. Intermediate polymer layer 270 defines one or more air spaces 272 disposed therein. In the exemplary embodiment, there are multiple air spaces 272 spaced apart and extending around the circumference of intermediate layer 270. Disposed near the inner surface of intermediate layer 270 is a coupler 266, which may be a metal tube cast from the elastomer. Coupler 266 is sized and shaped to slide over the torque tube or torsion beam of a solar tracker and, in the exemplary embodiment, has an octagonal cross-section.

[0084] In an exemplary embodiment, the housing 262 is substantially circular with extended sides and a substantially flat base. It is designed with a stop 264 at the bottom of the circular portion that houses the intermediate layer 270 and the metal tube 266. The housing 262 also has a center rib 274 in its base portion that is located directly below the stop 264. The exemplary embodiment includes at least one rotation stop 268 on the coupler 266. The rotation stop 268 can be located at each bottom corner of each lateral side of the coupler 266. The housing 262 advantageously rotates without any sliding surfaces. Instead, when the torque tube or torsion beam rotates about its rotation angle 276 (e.g. Figure 1 54 is also shown), the spring balance assembly 210 is bent in the middle elastomer layer and provides the rotational spring force. When the torque tube or torsion beam rotates to its limit, one of the rotation stops 268 on the coupler 266 hits the stop 264 of the housing 262. The elastomer between the metal stops acts as a soft stop for rotation.

[0085] Reference Figure 12 、 Figure 13A and Figure 13BA spring balance assembly with an integral longitudinal elastomeric torsion spring and a surface bearing providing inherent damping will now be described. The spring balance assembly 310 includes a bearing housing 362 and an inner elastomeric tube 374, which is bonded to two octagonal metal or plastic inserts at each end of the tube 374. The tube 374 rotates on a polymer bearing layer 367 within the bearing housing 362. The exemplary bearing housing 362 includes an upper circular portion 366 and a lower portion 368, with the lower portion 368 having a bottom surface for engaging mounting bolts 372 or other fastening mechanism. The housing 362 is made of aluminum, cast iron, an engineered polymer, or other suitable structural material. The upper and lower portions 366 and 368 are connected, and the entire housing 362 forms a circular interior. A circular bearing layer 367 is disposed at the ends of the interior of the housing 362 and is made of a polymer bearing material. The inner elastomeric torque tube 34 has an outer surface having a substantially circular cross-section that mates with the circular polymer bearing material 367, and an inner surface sized so that two shaped inserts bonded to each end can be slidably and rotationally keyed to the torque tube or torsion beam 34. In the exemplary embodiment, the inner surface has an octagonal cross-section.

[0086] The elastomeric torque tube layer 374 has at least one integrally formed protrusion that is bonded to the bearing housing 362. In the exemplary embodiment, the torque tube 34 is fixed to the center of the bearing housing 362, while each end is bonded to a torque tube or torsion beam. In this embodiment, the torque tube causes the elastomeric torsion spring 374 to twist relative to the bearing housing, thereby generating a balancing rotational force when rotating in either direction. The elastomeric torque tube 374 is anchored to the housing 362 by anti-rotation tabs 376 that interlock with holes in the upper portion 366 of the housing 362. When the desired rotation angle limit is reached, the rotation stop 364 engages the bearing housing 362 at a notch 365. The design of the spring balance assembly 310 advantageously minimizes the assembly's diameter by aligning the torsion spring layer 374 parallel to the axis of rotation. More specifically, the bearing ends of the surfaces of the stop 364 and the inner structural layer 374 are located at the ends of the housing 362 and bonded to the shape of the torque tube or torsion beam at those ends. The keyed end is molded into a resilient tube that is centrally connected to the housing 362 .

[0087] Now go to Figures 14A-17D, a spring balance assembly that provides a balancing spring force and inherent damping will now be described. As discussed in detail herein, the spring balance assembly 410 includes one or more compressible cords 478 to provide a rotationally balancing spring force and damping capability. In an exemplary embodiment, the compressible cords 478 are made of a flexible material, which can be an elastic material such as rubber. The lack of hysteresis in the rubber or other elastic material provides natural damping, eliminating the need for a damper in some cases. The compressible cords are incorporated into an assembly having a generally square bearing housing and a generally circular sleeve. Assembly 410 is designed to allow for a large degree of rotation and to offset heavy objects such as solar trackers that mount solar modules. More specifically, the square design allows for rotational motion up to approximately 48 degrees of rotation, plus or minus.

[0088] Assembly 410 includes a sleeve 470 sized and shaped to slide over or through a torque tube or torsion beam. The inner surface 472 of sleeve 470 can have any suitable shape to correspond to the cross-sectional shape of the torque tube or torsion beam. In the exemplary embodiment, inner surface 472 of sleeve 470 has an octagonal shape, and outer surface 480 is substantially circular and has four protrusions 486 to compress compressible cord 478 as it rotates. Spring balance assembly 410 also includes a bearing housing 476. Sleeve 470 is disposed within bearing housing 476, with compressible cord 478 positioned between sleeve 470 and bearing housing 476. Bearing housing 476 can have any suitable shape and, in the exemplary embodiment, is substantially square with four rounded corners.

[0089] In the exemplary embodiment, the sleeve 470 is disposed within the bearing housing 476 along with four compressible cords 478, each of which is located near a corner 484 of the bearing housing 476. More specifically, as Figure 14A and Figure 14B As best shown, when the sleeve 470 is provided with the bearing housing 476, four spaces 482 are defined between the sleeve's outer surface 480 and the inner surface of the bearing housing's radius 484. Each compressible cord 478 is positioned in a space 482 such that the compressible cord is securely positioned between the sleeve 470 and the bearing housing 476. The four generally circular protrusions of the sleeve's outer surface 480 may have flat portions 488 positioned to correspond with the spaces 482 such that the compressible cords 478 rest on the sleeve's flat portions.

[0090] like Figure 16BAs best shown, in the exemplary embodiment, the sleeve 470 has a relatively thinner cross-section at each flat portion 488 than a relatively thicker cross-section at the sleeve's more protrusions 486, and the sleeve's outer surface 480 alternates between the flat portions 488 and the plurality of rounded portions or protrusions 486. The thinner cross-section is designed to accommodate the compressible cord 478 at the flat portions 488 of the sleeve 470. Figure 16A and Figure 16B As best shown, each flat portion 488 of the sleeve 470 may define a transition 490 from one protrusion 486 to an adjacent protrusion 486 .

[0091] As sleeve 470 rotates, compressible cord 478 both rolls and compresses to provide a balanced rotational spring force. This force is a function of the hardness (rigidity) of the elastomer in relation to the geometry of sleeve 470 and bearing housing 476, which entrains compressible cord 478. In this embodiment, the spring bearing is designed to counteract the cantilevered rotational weight of a device mounted on a torque tube or torsion beam. The cantilevered weight is a sinusoidal function of the rotational angle, the weight, and the distance of the weight from the center of rotation. Therefore, it is advantageous to design the spring force curve of the elastomeric spring bearing assembly to provide a resistance curve that approximates a sinusoidal function of the rotational angle corresponding to the torque amplitude generated by the moment generated by the collector mounted on the torque tube or torsion beam.

[0092] The spring balance assembly 410 advantageously allows up to + or - 48 degrees of rotation and benefits from a small outer envelope and four compressible cords. Applications requiring + or - 48 degrees of rotation may benefit from this design because of its small radius from the center rotation point, which minimizes cantilever weight, and because the spring and damper loads are shared with the four compressible cords.

[0093] Reference Figures 18A-22 Another exemplary embodiment of a spring balance assembly 510 provides inherent damping by incorporating a compressible cord 576 into a circular three-lobed bearing housing and a modified Reuleaux triangle sleeve 570. In some applications, up to + or - 63 degrees of rotation is required, which the assembly 510 can facilitate.

[0094] As the torque tube or torsion beam 34 of the solar tracker assembly 12 rotates, the damping cords 578 compress as the sleeve 570 rotates about the rotation angle 592, while the bearing housing 576 remains in a fixed position. More specifically, as the sleeve 570 rotates and the sleeve's three protrusions 586 shift relative to the stationary bearing 576, each damping cord 578 compresses between the inner wall of the bearing housing 576 and the protruding surface 586 of the sleeve 570. As the position of each protrusion 586 changes, the size of the space 582 decreases. When the compressible cords 578 reach their maximum compressibility, they provide a rotational spring force and damping when compression is released due to the lack of hysteresis in the elastomeric material. The compressible cords 578 can be made of a flexible material, such as an elastic material, such as rubber. The inherent lack of hysteresis in rubber or other elastic materials provides natural damping, thus eliminating the need for a damper. Assembly 510 is designed to allow a large degree of rotation and to counteract cantilever moment loads from objects such as solar trackers to which solar modules are mounted.

[0095] Spring balance assembly 510 includes a sleeve 570 sized and shaped to slide over or through a torque tube or torsion beam. In an exemplary embodiment, an inner surface 572 of sleeve 570 has an octagonal shape. Sleeve 570 has a substantially triangular cross-section, and an outer surface 580 has three primarily flat portions 588 forming the sides of the triangle and three rounded portions or protrusions 586 forming the angles of the triangle. Bearing housing 576 has a generally hexagonal cross-section with six flat side portions 574 and six angled corners 584. Bearing housing 576 can be designed so that the angles are not exactly equal. In an exemplary embodiment, the base angle has a smaller angle than the top angle.

[0096] In the exemplary embodiment, sleeve 570 is disposed within bearing housing 576 such that each protrusion 586 of sleeve 570 is positioned adjacent one of three alternating internal angled corners 584 of bearing housing 576. Figure 18A As best shown, in this configuration of assembly 510 , each flat portion 588 of sleeve 570 is located at one of three other alternating internal angled corners 584 facing bearing housing 576 such that a space 582 is defined between each flat portion 588 and each internal angled corner 548 .

[0097] Sleeve 570 can be used with Figure 23A-Figure 256. In this variation of the spring balance assembly 510a, the bearing housing 676 is generally circular and has three protrusions 686, and the sleeve 570 is disposed within the bearing housing 676 such that each of the three major flat portions 588 of the sleeve 570 is located facing one of the protrusions 686, defining a space 582 between each flat portion 588 and each protrusion 686. The generally circular bearing housing with three protrusions, combined with the hexagonal design, provides better grip on the compressible cord at large rotational angles.

[0098] As the sleeve 570 rotates, the compressible cords 578 both roll and compress into a smaller space, generating a balancing spring force. Because the cantilevered weight of the device mounted on the torque tube or torsion beam 34 generates a moment about the center of rotation, the spring design is preferably constructed to equally counteract the moment generated by the device during rotation. The balancing force is a moment about the center of mass and is therefore a sinusoidal function of the angle of rotation. The torque generated by the cantilevered weight of the device is equal to sin * angle * weight * distance from the center of mass. This describes a sinusoidal function with an amplitude. To design a correspondingly equal balancing force, the generated rotational spring force should be sinusoidal in shape. The desired amplitude is derived from the compression of the compressible cords during rotation and their corresponding resistance to compression, or hardness, measured in durometer. The hardness of the elastomer, its properties during compression, and the geometric relationship between the sleeve enclosing the compressible cords and the bearing housing are interrelated variables to achieve the desired balancing amplitude, approximating a sinusoidal torque-resistance curve.

[0099] In the exemplary embodiment, compressible cords 578 are positioned between the sleeve 570 and the bearing housing 576. In the exemplary embodiment, there are three compressible cords 578, each of which is positioned adjacent an interior angled corner 584 of the bearing housing 576. More specifically, as best shown in FIG20 , each compressible cord 578 is positioned within one of three spaces 582 defined between three flat portions 588 of the sleeve 570 and the interior angled corner 584 of the bearing housing 576. Each compressible cord 578 is positioned within a space 582 such that the compressible cord is securely disposed between the sleeve 570 and the bearing housing 576.

[0100] The spring-balance assembly 510 advantageously allows for a wide range of rotation of the solar tracker 12, which can reach up to 126 degrees, or plus or minus at least 63 degrees. As the torque tube or torsion beam 34 of the solar tracker assembly 12 rotates, the sleeve 570 rotates, the bearing housing 576 remains in a fixed position, and the damping cords 578 compress. More specifically, as the sleeve 570 rotates about the rotational axis 592 and the sleeve's raised portion 586 shifts relative to the stationary bearing 576, each damping cord 578 compresses between the inner wall and each angled corner 584 of the bearing 576, as the edge of the sleeve's raised portion 586, located in space 582, decreases in size due to the changing position of each rounded portion 586. When the compressible cords 578 reach their maximum compressibility, they provide damping due to the lack of hysteresis in the rubber material. Furthermore, when the compressible cord 578 reaches its designed rotational limit, further rotation is possible, but the resistance to rotation can be designed to increase significantly as rotation exceeds a limit that will create a soft stop to the system's rotation.

[0101] When used in conjunction with a solar tracker's torsion limiter design, the exemplary embodiments of the spring-balanced assembly described herein allow the torsion limiter to release torsion purely as a function of wind-induced torque, rather than as a function of wind plus the torque induced by the cantilever in the system. This allows for more precise control of the torsion release and minimizes the speed and damping required in the system, as the weight of the system's cantilever is no longer applied to the torsion limiter and does not increase the torque force or resulting release speed.

[0102] Exemplary embodiments of spring-balanced assemblies used with torsion limiters eliminate the need for deadband and increase power plant density and overall land use efficiency. When used in conjunction with a torque limiter, they enable the torque limiter to react more precisely and predictably, as variables such as the tracker's position and cantilever weight play no role in the torque applied to the limiter. They also reduce the speed of the tracker system during torque release, as the additional variable cantilever weight does not increase dynamic loads once the torsion release motion is initiated. The exemplary design reduces shock loads through the counterweight and can also produce a soft stop when engaging mechanical stops on the tracker bearings.

[0103] Torque limiters, torque limiters, torque limiting clutches, and solar trackers incorporating torque and torque limiters are described in detail in U.S. Patent No. 9,581,678, issued on February 28, 2017, the entire contents of which are incorporated herein by reference. An exemplary gear drive system includes a torque limiting clutch and a gear assembly including at least one gear. In an exemplary embodiment, the gear drive system of a solar tracker includes a torque limiting clutch on a first-stage gear of the solar tracker. An exemplary embodiment may include a single-stage gear drive solar tracker, wherein the gear drive system is a single-stage worm gear drive that directly rotates a solar collector array. The gear assembly may include a one-way gearbox, and the torque limiter may be a torque limiting clutch contained within the gearbox. The torque limiter, in the form of a clutch, may be located between the output of the worm gear drive and the solar collector array. Exemplary embodiments also include two-stage or multi-stage solar trackers. The gear assembly includes at least one gear, and in an exemplary embodiment, the gear is a worm gear.

[0104] In an exemplary embodiment, a torque-limiting clutch is located between the output of the first-stage worm gear and the connection to the second-stage gear. The torque-limiting clutch can be located at the output of the gear assembly, at the output of the solar tracker's first-stage gear, and before the gear drive system engages the solar tracker's rack gear. The clutch can be located at two tapered portions of the worm gear. Two steel cones engage the worm gear under spring tension, which can be adjusted via a nut or other adjustment mechanism. The torque limiter can be a motor brake located at the input of a bidirectional gearbox, rather than a clutch. The torque limiter can be an electric motor connected to an asymmetric input / output bidirectional gearbox, where the efficiency of driving the gearbox input is greater than the efficiency of driving the gearbox output. The solar tracker can be a push / pull link tracker, and the torque limiter can be a linear slide. The solar tracker can include a hydraulic system, and the torque limiter can be a pressure reducing valve. In an exemplary embodiment, the torque-limiting mechanism can be a bidirectional gear drive motor assembly that reverses at a predetermined torque.

[0105] In an exemplary embodiment, a torque-limiting clutch can be incorporated into multiple solar trackers connected in an array configuration consisting of one or more rows of solar trackers. In an exemplary embodiment, one spring is connected to a torque tube or torsion beam at or near a first end of a tracker row, and another spring is connected to the torque tube or torsion beam at or near a second end of the row. As described above, each spring can be incorporated into a spring balance assembly or into a damper or bearing housing assembly. Advantages of the embodiments discussed above include less stress on the tracker's drive system, less deflection in the torque tube or solar structure, less material required in the torque tube or torsion beam in the case of a torsional deflection control design, and the ability to use less complex pivots and structures.

[0106] Thus, it can be seen that spring balancing assemblies, systems, and methods are provided that can be incorporated into systems such as solar trackers. While the systems, devices, and methods have been described in terms of exemplary embodiments, it should be understood that the present disclosure is not necessarily limited to the disclosed embodiments. While illustrative embodiments have been described above, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the present disclosure.

[0107] It should be understood that any of the aforementioned configurations and specialized components or chemical compounds can be used interchangeably with any of the systems of the aforementioned embodiments. It is intended to encompass various modifications and similar arrangements included within the spirit and scope of the claims, the scope of which should be accorded the broadest interpretation to encompass all such modifications and similar structures. This disclosure includes any and all embodiments of the following claims. It is intended that the appended claims cover all such variations and modifications that fall within the true spirit and scope of this disclosure.

Claims

1. A solar tracker assembly comprising: Torque tube; a column supporting the torque tube; a solar module attached to the torque tube; a drive system attached to the torque tube, the drive system configured to rotate the torque tube and the solar module relative to the column from a first position in which the solar module creates a cantilevered weight on a left side of the torque tube to a second position in which the solar module creates a cantilevered weight on a right side of the torque tube; as well as A balancing assembly comprising: a top bracket secured to a torque tube so that the top bracket rotates with the torque tube; a bottom bracket secured to a column supporting the torque tube; and a spring element attached at one end to the top bracket and at an opposite end to the bottom bracket, wherein the spring element provides a balance for the cantilevered weight of the solar module in a first position and the cantilevered weight of the solar module in a second position.

2. The solar tracker assembly of claim 1, wherein: The top bracket includes a flange portion, and the spring element is attached to the top bracket at or near an end of the flange portion. 3 . The solar tracker assembly of claim 2 , wherein the flange portion of the top bracket has a tapered shape such that the flange portion narrows toward an end.

4. The solar tracker assembly of claim 1 , wherein the top bracket is secured to the torque tube by an elongated strap attachable to the top bracket at each end and sized and shaped to surround the torque tube.

5. The solar tracker assembly of claim 4, wherein the elongated strap is shaped to surround a torque tube having a circular cross-sectional shape.

6. The solar tracker assembly of claim 1, wherein the base bracket is configured to be securable to the post at different locations on the post.

7. The solar tracker assembly of claim 1 , further comprising a damper having one end attached to the top bracket and an opposite end attached to the bottom bracket.

8. A solar tracker assembly comprising: Torque tube; a column supporting the torque tube; a solar module attached to the torque tube; a drive system attached to the torque tube, the drive system configured to rotate the torque tube and the solar module relative to the mast; as well as A balancing assembly comprising: a top bracket secured to a torque tube so that the top bracket rotates with the torque tube; a bottom bracket secured to a column supporting the torque tube; and a spring element attached at one end to the top bracket and at an opposite end to the bottom bracket, wherein the top bracket includes a flange portion having a tapered end and the spring element is attached to the top bracket at or near the tapered end of the flange portion.

9. The solar tracker assembly of claim 8, wherein: The top bracket is secured to the torque tube by an elongated strap that is attachable to the top bracket at each end and is sized and shaped to surround the torque tube.

10. The solar tracker assembly of claim 9, wherein: The elongated strip is shaped to surround a torque tube having a circular cross-sectional shape.

11. The solar tracker assembly of claim 8, wherein: The bottom bracket is configured to be securable to the post at various locations on the post.

12. The solar tracker assembly of claim 8, further comprising a damper having one end attached to the top bracket and an opposite end attached to the bottom bracket.

Images