BEARING HOUSING ASSEMBLY FOR SOLAR TRACKERS

A coupling system for use with a solar tracker includes a torque tube coupling defining an arcuate slot therethrough, a mounting bracket couplable to a portion of a pier, and a first fastener, a portion of the first fastener slidably and rotatably received within a portion of the slot to enable polyaxial rotation of the torque tube coupling relative to the mounting bracket.

BACKGROUND

Technical Field

The present disclosure relates to solar power generation systems, and more particularly, to couplings for accommodating misalignment and thermal expansion of torque tubes of solar trackers.

Background of Related Art

To follow the trajectory of the sun, solar trackers mount solar modules on torque tube which is rotatably supported on a plurality of piers. During operation of the solar tracker, thermal fluctuations occur daily and seasonably resulting in thermal expansion and contraction of the solar tracker components. In many instances, thermal expansion is not significant enough to impart noticeable forces on the components. However, the torque tubes of the solar trackers can span significant lengths, which results in noticeable expansion and contraction during daily and seasonal temperature fluctuations.

As can be appreciated, the thermal expansion and contraction of the torque tubes can impart not so insignificant axial loads on the support structures. The torque tubes of the solar tracker are rotatably supported on the piers by a coupling. These couplings enable the torque tube to rotate about its longitudinal axis and in many embodiments, enable the torque tube to axially slide within the coupling to accommodate thermal expansion and contraction of the torque tube. As can be appreciated, axial movement of the torque tube can impart significant loads on the couplings and the piers supporting them. Axial forces due to expansion and contraction of the torque tube can cause the piers to deflect or otherwise deform to accommodate this axial movement by the torque tube. This deflection by the piers can cause misalignment of the couplings with respect to the torque tubes, which can cause increased friction or binding of the torque tube as the torque tube is rotated within the couplings. This binding or increased friction increases the amount of force required to rotate the torque tube, which in turn, imparts increased load on the actuators or motors effectuating the rotation, and in some instances can cause the torque tube to twist along its length, causing some solar panels to rotate more or less than other solar panels along the length of the torque tube.

SUMMARY

In accordance with an aspect of the present disclosure, a coupling system for use with a solar tracker includes a torque tube coupling, the torque tube coupling defining an arcuate slot therethrough, a mounting bracket, the mounting bracket couplable to a portion of a pier, and a first fastener, a portion of the first fastener slidably and rotatably received within a portion of the slot to enable polyaxial rotation of the torque tube coupling relative to the mounting bracket.

In aspects, the first fastener may enable the torque tube coupling to rotate relative to the mounting bracket about a first axis defined through a length of the torque tube coupling.

In other aspects, the first fastener may enable the torque tube coupling to rotate relative to the mounting bracket about a second axis defined transverse to the first axis.

In certain aspects, the coupling system may include a spherical coupled to a portion of the first fastener and slidably and rotatably received within the slot of the torque tube coupling.

In other aspects, the arcuate slot may define a curvate profile along the length of the slot to retain the spherical therein.

In aspects, the coupling system may include a second fastener disposed in spaced relation to the first fastener, a portion of the second fastener slidably and rotatably received within a portion of the slot to enable polyaxial rotation of the torque tube coupling relative to the mounting bracket.

In other aspects, each of the first and second fasteners may include a respective first and second spherical disposed thereon, the first and second sphericals slidably and rotatably received within the slot of the torque tube coupling.

In certain aspects, the torque tube coupling may include a notch defined therethrough, the notch configured to receive a portion of a torque tube therein.

In aspects, the coupling system may include a torque tube clamp selectively couplable to a portion of the torque tube coupling, the torque tube clamp configured to abut a portion of a torque tube received within the notch to couple the torque tube to the torque tube coupling.

In other aspects, the torque tube clamp may include a protuberance disposed thereon that is configured to abut a portion of the torque tube.

In certain aspects, the torque tube clamp may include a pair of opposed flanges disposed thereon to engage a respective portion of the torque tube coupling to inhibit movement of the torque tube clamp along a transverse axis defined through the torque tube coupling.

In accordance with another aspect of the present disclosure, a coupling system for use with a solar tracker includes a torque tube coupling, the torque tube coupling defining an arcuate slot therethrough, a mounting bracket, the mounting bracket couplable to a portion of a pier, and a first fastener assembly, the first fastener assembly including a bolt selectively couplable to a portion of the mounting bracket and selectively received through a portion of the slot of the torque tube coupling, and a spherical rotatably disposed on a portion of the bolt, the spherical slidably and rotatably received within a portion of the slot to enable polyaxial rotation of the torque tube coupling relative to the mounting bracket.

In aspects, the coupling system may include a second fastener assembly disposed in spaced relation to the first fastener assembly, the second fastener assembly including a second blot selectively couplable to a portion of the mounting bracket and selectively received through a portion of the slot of the torque tube coupling, and a second spherical rotatably disposed on a portion of the blot, the second spherical slidably and rotatably received within a portion of the slot to enable polyaxial rotation of the torque tube coupling relative to the mounting bracket.

In certain aspects, the torque tube coupling may include a notch defined therein, the notch configured to receive a portion of a torque tube therein.

In other aspects, the coupling system may include a torque tube clamp selectively couplable to a portion of the torque tube coupling, the torque tube clamp configured to abut a portion of a torque tube received within the notch to couple the torque tube to the torque tube coupling.

In certain aspects, the torque tube coupling may be formed by stamping.

In accordance with another aspect of the present disclosure, a coupling system for use with a solar tracker includes a pier extending between opposed first and second end portions, a mounting bracket coupled to the second end portion of the pier, a torque tube coupling operably coupled to the mounting bracket, the mounting bracket permitting polyaxial rotation of the torque tube coupling relative to the mounting bracket as the second end portion of the pier is caused to be deflected relative to the first end portion.

In aspects, the coupling system may include a torque tube selectively coupled to a portion of the torque tube coupling, wherein axial expansion and contraction of the torque tube effectuates a corresponding deflection of the first end portion of the pier.

In certain aspects, the torque tube coupling may include an arcuate slot defined therein configured to slidably and rotatably receive a portion of a spherical therein, the spherical operably coupled to a portion of the mounting bracket.

In other aspects, the torque tube coupling may include a notch defined therein, the notch configured to selectively receive a portion of the torque tube therein.

DETAILED DESCRIPTION

The present disclosure is directed to a coupling system for use with a solar tracker. The coupling system, or bearing housing assembly, includes a pair of pier couplings, a mounting bracket, a torque tube coupling assembly, and a pair of fastener assemblies. The pair of pier couplings is configured to selectively couple the mounting bracket to a pier of the solar tracker. The mounting bracket is selectively coupled to the pair of pier couplings and is configured to operably support the torque tube coupling assembly thereon. In this manner, the mounting bracket includes a pair of through-holes defined therethrough that is configured to receive a respective fastener assembly of the pair of fastener assemblies therethrough.

The torque tube coupling assembly includes a pair of half-sections and a torque tube clamp selectively coupled thereto. The pair of half-sections define a generally half-circle or taco profile and include an arcuate slot defined therethrough adjacent a lower arcuate outer surface. The arcuate slot of each half-section of the pair of half sections includes an upturned flange extending along a perimeter thereof to which a pair of plates are clinched or otherwise coupled to, which forms a raceway in which a spherical or ball is cradled, cupped, or otherwise retained. The pair of plates define an arcuate profile when viewed from a side of the pair of half-sections to accommodate the spherical profile of the spherical. As can be appreciated, the clinching of the pair of plates to the upturned flanges of the slots of the pair of half-sections inhibits the pair of half-sections from splitting apart or otherwise being separated. Each of the pair of half-sections includes a notch defined therein and through an upper surface thereof that is configured to selectively receive a portion of a torque tube therein. As such, rotation of the torque tube effectuates a corresponding rotation of the pair of half-sections.

The torque tube clamp defines a generally U-shaped profile and includes a protuberance disposed on a backspan thereof that is configured to abut or otherwise contact a torque tube. In this manner, the torque tube clamp is selectively coupled to the pair of half-sections to clamp or otherwise couple a torque tube to the pair of half-sections when the torque tube is disposed within the notch of the pair of half-sections. As can be appreciated, with the torque tube coupled to the pair of half-sections, rotation of the torque tube effectuates a corresponding rotation of the torque tube coupling assembly and axial movement of the torque tube effectuates a corresponding axial movement of the torque tube coupling assembly.

The pair of fastener assemblies includes a bolt, a pair of sleeves, a spherical, and a nut. The spherical is a spherical bearing, ball bearing, or the like and is configured to be received within the slot or raceway of the torque tube coupling assembly such that the torque tube coupling assembly is permitted to rotate about a first axis defined through a longitudinal axis of the torque tube and rotate about a second axis defined transverse to the first axis and through a center of the spherical bearings of each of the pair of fastener assemblies. The sphericals of each of the pair of fastener assemblies are disposed in spaced relation to one another and are rotatably supported on the bolt. In this manner, the bolt is selectively received within a corresponding bore defined through the mounting bracket and extends through the slot of the torque tube coupling assembly. Each of the pair of sleeves is disposed on opposing sides of the spherical and are supported on the bolt. In this manner, the pair of sleeves is interposed between the spherical and the mounting bracket on each side of the spherical. The nut is threadably engaged with the bolt and secures the fastener assembly to the mounting bracket.

In operation, with the torque tube coupled to the coupling assembly, as the torque tube expands and contracts due to daily or seasonal temperature fluctuations, the torque tube coupling assembly is caused to likewise translate relative to the pier on which the coupling assembly is supported. The axial motion torque tube and torque tube coupling assembly exerts an axial force on the spherical of the fastener assembly, which in turn exerts a force on the mounting bracket, pair of pier couplings, and the pier. Continued axial motion of the torque tube causes the pier to deflect or otherwise bend relative to the ground, causing the mounting bracket to form an angle relative to the torque tube. To avoid misalignment and binding of the torque tube within the torque tube coupling assembly, the spherical enables the torque tube coupling assembly to rotate relative to the pier and mounting bracket to maintain a generally perpendicular angle relative to the torque tube. Therefore, the torque tube is permitted to freely rotate relative to the pier on the sphericals of the pair of fastener assemblies. These and other aspects of the present disclosure will be described in detail herein below with reference to the drawings.

Referring now to the drawings, a solar tracker provided in accordance with the present disclosure is illustrated inFIG.1and generally identified by reference numeral10. The solar tracker10includes a plurality of piers12disposed in spaced relation to one another and embedded in the earth. A torque tube14extends between each adjacent pier12and is rotatably supported on each pier12. The torque tube14is rotatably supported on each pier12by a coupling assembly or bearing housing assembly (BHA)20, a slew drive (not shown), amongst others. In one non-limiting embodiment, the torque tube is rotatably supported on each pier12by a respective BHA20, as will be described in further detail hereinbelow.

The solar tracker10includes a plurality of solar panels16supported on each respective torque tube14. The span between two adjacent piers12is referred to as a bay18and may be generally in the range of about 8 meters in length. A plurality of solar trackers10may be arranged in a north-south longitudinal orientation to form a solar array.

With reference toFIG.2-8, the coupling assembly or BHA20includes a pair of pier couplings22, a mounting bracket40, a torque tube coupling assembly60, and a pair of fastener assemblies100. Each of the pair of pier couplings22is substantially similar to one another, and therefore, only one pier coupling22will be described in detail herein in the interest of brevity. The pier coupling22defines a generally lowercase ‘r” profile, having a first leg24extending between opposed upper and lower portions24aand24b, respectively, and a second, generally transverse leg26extending between opposed first and second end portions26aand26b, respectively (FIG.3). The second leg26is coupled to the upper portion24aof the first leg adjacent the second end portion26aand extends therefrom. Although generally described as being disposed transverse to the first leg24, it is contemplated that the second leg26may define any suitable angle relative to the first leg24.

The first leg24is coupled to a respective pier12using any suitable means, such as fasteners, welding, adhesives, amongst others and the second leg26is coupled to a portion of the mounting bracket40using any suitable means, such as fasteners, welding, adhesives, amongst others, and may be coupled to the mounting bracket40using the same or different means employed for coupling the pier coupling22to the pier12. As can be appreciated, the pier coupling22fastens or otherwise couples the mounting bracket40to a pier12such that forces transmitted to the pier coupling22are transferred to the pier12.

In embodiments, the pier coupling22may include one or more gussets28extending between the first leg24and the second leg26to stiffen or otherwise strengthen the pier coupling22. It is envisioned that the pier coupling22may be formed as a unitary component by stamping, hydroforming, machining, additive manufacturing, amongst others, or in embodiments, may be formed from one or more components joined together via welding, fasteners, adhesives, clinching, amongst others.

With reference toFIG.3, the mounting bracket40defines a generally U-shaped configuration having a backspan42extending between opposed vertical flanges44and46, respectively. As described hereinabove, it is envisioned that the backspan42of the mounting bracket40may be coupled to each of the pier couplings22using any suitable means, such as fasteners, welding, adhesives, amongst others. The opposed vertical flanges44,46are substantially similar to one another and therefore, only one vertical flange26will be described in detail herein in the interest of brevity. The vertical flange44extends from the backspan42and terminates at an end portion44a. Although generally illustrated as defining a trapezoidal profile, it is envisioned that the vertical flange44may define any suitable profile, such as rectangular, square, oval, racetrack, amongst others. The vertical flange44includes a pair of through-holes48defined therethrough adjacent the end portion44aand disposed in spaced relation to one another. The pair of through-holes48is configured to receive a respective fastener therethrough, as will be described in further detail hereinbelow. In embodiments, the vertical flange44may include a tab50disposed on the end portion44aat a center portion thereof. The vertical flange44may include an aperture defined therethrough that is configured to receive a fastener (not shown) or the like. It is envisioned that the mounting bracket40may be formed as a unitary component by stamping, hydroforming, machining, additive manufacturing, amongst others, or in embodiments, may be formed from one or more components joined together via welding, fasteners, adhesives, clinching, amongst others.

With reference toFIGS.5and6, the torque tube coupling assembly60includes a pair of half-sections62coupled to and disposed in juxtaposed relationship to one another and a torque tube clamp90configured to clamp or otherwise couple a torque tube14to the pair of half-sections62as will be described in further detail hereinbelow.

Each of the pair of half sections62is substantially similar to one another and therefore, only one half-section62will be described in detail herein in the interest of brevity. The half section62defines a generally half-circle or taco shaped configuration defining a generally planar upper surface64and a generally arcuate lower surface66extending between opposed end portions of the upper surface64. The half section62includes a generally planar center surface68interposed between the upper surface64and the arcuate lower surface66defining a cavity70therebetween.

The center surface68includes a slot72defined therein having a generally arcuate profile and generally following the arcuate profile of the arcuate lower surface66, although it is contemplated that the slot72may include any suitable profile and length, depending upon the design needs of the torque tube coupling assembly60. The slot72defines an upturned flange74extending around the perimeter of the slot72and extending away from the center surface68. The upturned flange74defines a generally arcuate profile arcing towards an interior portion of the slot72, although it is contemplated that the upturned flange74may define any suitable profile, such as linear, sinusoidal, amongst others. With reference toFIG.6, when the pair of half sections62is coupled to one another, the slot72is generally aligned in each of the pair of half sections62and the upturned flange74of each of the pair of half-sections62extends in opposing directions defining a raceway therebetween for receipt of a spherical, ball bearing, or the like, as will be described in further detail hereinbelow.

The center surface68of the half section62defines a notch76therethrough which extends through the upper surface64. The notch76is configured to receive a portion of a torque tube14therein. In this manner, the notch76may define a profile that complementary to an outer profile of the torque tube14(e.g., D-shaped, circular, oval, amongst others) or in embodiments may be different that the outer profile of the torque tube14. In one non-limiting embodiment, the notch76defines a generally U-shaped profile to receive a portion of the torque tube14therein. In embodiments, the notch76may include an upturned flange78extending into the cavity70. It is envisioned that the upturned flange78may extend any suitable distance and may be the same or similar distance to that of the upper surface64and the arcuate lower surface66. As can be appreciated, the upturned flange78provides an increased bearing area on which the torque tube14can abut. It is envisioned that the pair of half sections62may be formed from any suitable material, such as a metallic material, a non-metallic material, a composite, amongst others, and may be formed from one or more pieces of material using any suitable method such as stamping, hydroforming, additive manufacturing, welding, machining, adhesives, amongst others. In embodiments, each of the pair of half sections62may be formed form the same or different material from one another, depending upon the design needs of the torque tube coupling assembly60.

It is contemplated that each of the pair of half sections62is coupled to one another using any suitable means, such as welding, adhesives, fasteners, clinching, amongst others. In one non-limiting embodiment, the pair of half-sections62includes a pair of plates80,82disposed on opposed portions of the slot72(e.g., upper and lower portions). Each of the pair of plates80,82defines a generally arcuate (e.g., concave) profile when viewed from a side portion of the pair of half-sections62and generally follow the arcuate profile of the slot72along its length. In this manner, the pair of plates80,82cooperate to define a circular or oval slot in which a ball bearing or the like can be disposed (e.g., cradled, clinched, etc.) to accommodate polyaxial movement of the torque tube coupling60relative to the pier12as the torque tube14expands and contracts in an axial direction. Each of the pair of plates80,82is clamped or otherwise clinched onto a portion of each respective upturned flange78to aid in securing the pair of half-sections62to one another and maintain the pair of plates80,82in the proper location during use. It is contemplated that the pair of plates80,82may be formed from the same or different material than the pair of half-sections62. In one non-limiting embodiment, the pair of plates80,82is formed from a material that is harder than the pair of half-sections62to inhibit the spherical from deforming or otherwise wearing the pair of plates80,82as the spherical rides or translates within the slot72.

With reference toFIG.7, the torque tube clamp90defines a generally U-shaped configuration having a backspan92extending between a pair of opposed flanges94disposed in a transverse orientation to the backspan92and defining a cavity96therebetween. The pair of opposed vertical flanges94is disposed in spaced relation to one another such that each of the pair of opposed vertical flanges94abuts or otherwise overhangs an outer portion of the upper surface64of each of the pair of half-sections62to aid in locating the torque tube clamp90relative to the pair of half-sections62and aid in clamping or otherwise coupling the pair of half-sections62to one another. The backspan92includes a protuberance98formed thereon that extends into the cavity96formed between the pair of opposed flanges94. In embodiments, the protuberance98extends past the pair of opposed vertical flanges94such that the protuberance98abuts or otherwise clamps or squeezes a torque tube when the torque tube is received within the notch76. In this manner, the torque tube clamp90is selectively coupled to a portion of one or both of the pair of half-sections62using any suitable means, such as fasteners, clamps, adhesives, welding, amongst others. In one non-limiting embodiment, the torque tube clamp90is selectively coupled to the pair of half-sections62using a pair of fasteners. It is envisioned that the torque tube clamp90may be formed from any suitable material, such as a metallic material, a non-metallic material, a composite, or the like, and may formed from the same or different material than the various components described herein. In embodiments, the torque tube clamp90is formed from one or more pieces of material using any suitable method, such as stamping, hydroforming, machining, additive manufacturing, welding, adhesives, amongst others.

With additional reference toFIGS.6and8, the pair of fastener assemblies100are substantially similar and therefore, only one fastener assembly100will be described in detail herein in the interest of brevity. The fastener assembly100includes a bolt102, a pair of sleeves104, a ball or spherical106, and a nut108. The bolt102includes a head102aand a shank102bdisposed thereon and extending therefrom. The shank102bis at least partially threaded to threadably engage a threaded portion of the nut108and includes an outer dimension that is configured to be received within the pair of through-holes48of the mounting bracket40. Although generally illustrated as being a hex bolt, it is contemplated that the bolt102may be any suitable fastener, such as a cap screw, threaded rod, unthreaded rod, amongst others.

Each of the pair of sleeves104is substantially similar to one another and therefore, only one sleeve104will be described in detail herein in the interest of brevity. The sleeve104extends between opposed first and second end portions104aand104brespectively and defines a generally circular cross-section, although it is contemplated that the sleeve104may define any suitable cross-section, such as square, rectangular, oval, hexagonal, amongst others. The sleeve104includes a through-bore104cdefined through the first and second end portions104a,104bthat includes an inner dimension that is configured to receive a portion of the shank102bof the bolt, as will be described in further detail hereinbelow.

Each of the pair of sleeves104is configured to be interposed between an inner portion of the opposed vertical flanges44,46of the mounting bracket40and the spherical106, such that a sleeve of the pair of sleeves104is disposed on either side of the spherical106to center or otherwise maintain the torque tube coupling assembly60at a central location between the opposed vertical flanges44,46. In embodiments, each of the pair of sleeves104includes a length that leaves a gap or space between the pair of sleeves104and the spherical106and/or the opposed vertical flanges44,46of the mounting bracket40to enable the torque tube coupling assembly60to freely move relative to the mounting bracket40. Although generally described has leaving a gap between the between the pair of sleeves104and the spherical106and/or the opposed vertical flanges44,46, it is envisioned that the pair of sleeves104may include any suitable length and may the same length of may have different lengths depending upon the design needs of the BHA20.

The spherical106defines a generally spherical profile having a centerbore106adefined therethrough that is configured to receive a portion of the shank102bof the bolt102therethrough. The spherical106includes an outer dimension that is configured to be slidably received within the slot72of the torque tube coupling assembly60such that the spherical106abuts or otherwise rides against one or both of the pair of plates80,82. As can be appreciated, the arcuate profile of the pair of plates80,82cradles or otherwise cups the ball or spherical106to inhibit movement in a transverse or axial direction relative to the bolt102while permitting the torque tube coupling assembly60to pivot or otherwise rotate about the spherical106. It is contemplated that the spherical106may be a spherical bearing, a ball bearing, amongst others, and may include a hardness suitable to resist deforming or the like from a load imparted thereon.

The nut108threadably engages the threaded portion of the shank102bof the bolt102to capture or otherwise secure the bolt102, the pair of sleeves104, the spherical106, and the torque tube coupling assembly60to the mounting bracket40. It is envisioned that the nut108may be any suitable fastener, such as a flange nut, lock nut, amongst others.

With reference toFIG.9, in operation, the torque tube14is disposed within the notch76of the torque tube coupling assembly60and the torque tube clamp90is secured or otherwise coupled to the pair of half-sections62to clamp or otherwise inhibit movement of the torque tube14relative to the torque tube coupling assembly60. As the torque tube14expands or contracts due to daily temperature fluctuations or seasonal changes, the torque tube14applies an axial force on the torque tube coupling assembly60in a pushing or pulling manner. The axial force placed upon the torque tube coupling assembly60is transferred to the spherical106, which in turn, transfers the force to one or both of the pair of sleeves104, which in turn, transfers the force to the mounting bracket40. The force applied to the mounting bracket40is transferred to the pair of pier couplings22, and therefore, the pier12. As can be appreciated, the axial force applied to the pier12causes the pier12to deflect or otherwise bend relative to the ground, due to the pier12being embedded in the earth, which forms an angle relative to the torque tube14. This deflection by the pier12causes the BHA20to likewise form an angle relative to the torque tube14, which can cause binding or otherwise inhibit rotation of the torque tube relative to the pier12.

The circular profile of the spherical106enables the torque tube coupling assembly60to maintain a generally 90-degree angle relative to the torque tube14as the torque tube coupling assembly60is caused to translate axially relative to the pier12, while enabling the pier12and the mounting bracket40to deflect and form an angle relative to the torque tube coupling assembly60. It is envisioned that the spherical106enable the pier12and, therefore, the mounting bracket40to rotate up to about 5 degrees relative to the torque tube coupling assembly60without causing the torque tube14to bind or be inhibited from rotating relative to the pier12. As can be appreciated, the arcuate slot72of the pair of half-sections62forms a raceway through which the spherical106can ride as the torque tube coupling assembly60is caused to be rotated by the torque tube14relative to the pier12. In embodiments, the slot72includes a length that enables the torque tube coupling assembly62to rotate through a range of about 55 degrees.