Sliding bearing arrangement for a drive unit and drive unit for a tracking system for solar panels

Abstract

Sliding bearing arrangement (600) comprising an outer ring (610) with a sliding lining (611) in which a shaft (200) is mounted, where the shaft (200) is formed in an axial direction into an inner shaft part (220) and at least one outer shaft part (210), wherein the inner shaft part (220) is designed to be supported opposite the outer ring (610) and is sealed against it by an inner sliding bearing seal (630), and the outer shaft part (210) is elastically and positively connected to the outer ring (610) by an outer sliding bearing seal (640).

Description

[0001] The invention relates to a sliding bearing arrangement for a drive unit and a drive system for a tracking system for solar panels.

[0002] Solar power plants are increasingly being equipped with tracking systems during industrial construction projects. Tracking systems, also known as solar trackers, align solar panels according to the current sunlight to increase the efficiency of power generation. This is typically achieved by mounting several solar panels on a rotating axis and aligning them according to the angle of the sunlight via a mechanical drive unit.

[0003] Tracking systems theoretically increase energy yield by up to 30% for single-axis systems and 45% for dual-axis systems. Improvements achieved so far, for example in the USA, range from 20% to 25% for single-axis trackers. The costs are less than 7% higher compared to fixed-mount panels.

[0004] German patent DE 20 2007 01 2008 U1 describes a tracking system for solar modules, mounted on a foundation and a rotatably mounted structure, which is rotated by a drive system depending on the position of the sun. A similar arrangement is also shown in US patent 2023 / 0 336 113 A1.

[0005] EP 2 154 449 A2 describes a solar tracker system with several tracker devices, each having a base on which a fifth wheel coupling with a vertical axis is located, the rotatable part of which carries a scaffold structure for receiving a flat frame which carries photovoltaic modules, wherein this flat frame can pivot on the scaffold structure about a horizontal axis.

[0006] DE 20 2015 003 869 U1 describes a single-axis solar tracker with a multitude of solar panels mounted on a shaft which rotates the solar panels according to the relative movements of the sun.

[0007] A typical industrial photovoltaic system consists of numerous solar panels. These panels are arranged in rows along long shafts, which are driven by one or more actuators.

[0008] Such a system, and therefore also its rotary drive system, is exposed to particular environmental influences such as dirt and moisture. The drive system should be sealed in such a way that maintenance or even repairs – if necessary at all – are only required at long intervals. Furthermore, the drive system should be as cost-effective to produce as possible.

[0009] The object of the invention is therefore to provide a bearing with a sealing mechanism that is suitable to effectively protect a previously described tracking system, in particular the rotary drive system, against environmental influences.

[0010] This invention is solved by a sliding bearing arrangement according to claim 1 and by a drive unit according to claim 8.

[0011] The core idea of ​​the invention takes up the realization that the requirements for a seal in a rotary drive with only very slight rotational movement (swivel angle less than 180 degrees) are completely different from the requirements placed on seals in drives with continuous rotation.

[0012] The sliding bearing arrangement according to the invention comprises an outer ring, for example as part of a housing. This outer ring is stationary and carries a sliding lining. A shaft is mounted within this outer ring. According to the invention, this shaft is divided axially. It consists of an inner shaft section and at least one outer shaft section. The inner shaft section is designed to support the outer ring. The inner shaft section must therefore meet the requirements of a sliding partner vis-à-vis the outer ring, whereas this requirement does not apply to the outer shaft section, and even slight twisting does not result in any functional impairment of the tracking system. For this reason, a significantly more cost-effective material can be selected for the outer shaft section.Preferably, this axial shaft section of the inner shaft part is made of a high-quality material, while the at least one outer shaft part can be made of a lower-quality and therefore more cost-effective material.

[0013] Preferably, the shaft comprises an inner shaft part and two outer shaft parts arranged axially on both sides of the inner shaft part.

[0014] The inner shaft part preferably has at least one groove and the outer shaft part has at least one spring, wherein the groove and spring are complementary and form a positive fit to each other.

[0015] According to the invention, the outer shaft part rests elastically and positively against the outer ring via an outer sliding bearing seal.

[0016] In a preferred embodiment, the outer shaft section comprises a polygonal shaft and a shaft collar adjoining the inner shaft section. An outer sliding bearing seal is arranged radially around the outer circumference of the shaft collar.

[0017] In a preferred embodiment, the outer sliding bearing seal is designed as a multi-lipped seal.

[0018] The outer sliding bearing seal preferably contains grease deposits.

[0019] Preferably, the outer sliding bearing seal is made of polyurethane elastomer.

[0020] The invention further includes a drive unit for a shaft which is divided in the axial direction into an inner shaft part and at least one outer shaft part, wherein the drive unit includes a sliding bearing arrangement as described above.

[0021] The invention further encompasses a tracking system for solar panels comprising a shaft that is axially split as described and includes an inner shaft section and at least one outer shaft section. The shaft is supported on supports in one or more bearings. Solar panels are fixed to the shaft, which is pivotable by at least one drive unit as described above.

[0022] The invention also encompasses a photovoltaic system comprising solar panels with a tracking system described above.

[0023] Further aspects of the invention can be seen in the figures described below. Fig. 1. the basic structure of a photovoltaic system, Fig. 2 a three-dimensional representation of the drive arrangement according to the invention Fig. 3 a partial sectional view of the sliding bearing arrangement according to the invention Fig. 4 a partial sectional view of the sliding bearing arrangement according to the invention Fig. 5 a partial sectional view of the sliding bearing arrangement according to the invention

[0024] Fig. Figure 1 shows the basic structure of a rotary-tracking photovoltaic system 1. For tracking, a shaft 200 is mounted in bearings 300 on supports 400. Solar panels 100 are fixed to the shaft 200. In this embodiment, the entire combination of shaft 200, solar panels 100, and mountings 101 is pivoted back and forth around the longitudinal axis of the shaft 200, following the direction of the sunlight, by a single drive unit 500, designed as a rotary actuator. The pivoting movement is indicated by the arrow 201.

[0025] Photovoltaic systems are exposed to environmental influences such as dirt and moisture. Accordingly, a sliding bearing arrangement is provided according to the invention, which is described with reference to the further figures:

[0026] Fig. Figure 2 shows a three-dimensional representation of the drive unit 500 according to the invention. This unit comprises a sliding bearing arrangement 600, which supports a shaft consisting of two outer shaft sections 210 and an inner shaft section (not visible here because it is enclosed by the sliding bearing arrangement 600). The outer shaft sections 210 comprise a shaft polygon 211 and a shaft collar 212, which adjoins the inner shaft section. The sliding lining 611 is also visible. The outer sliding bearing seal according to the invention is not visible here.

[0027] Figures 3, 4, and 5 each show a partial sectional view of the sliding bearing arrangement 600 according to the invention from different perspectives. The inner shaft section 220 and an outer shaft section 210 are shown in each figure. The inner shaft section 220 is the rotating sliding bearing partner to the stationary outer sliding bearing ring 610, which carries the sliding lining 611. The outer sliding bearing ring 610 also serves as a stop for the outer sliding bearing seal 640, which is arranged on the circumference of the shaft collar 212 of the outer shaft section 210. A conventional inner sliding bearing seal 630 is also visible.

[0028] Fig. Figure 5 additionally shows the connection between the inner shaft part 220 and the outer shaft part 210 via a groove 221 and a spring 213. Reference sign 1 photovoltaic system 100 solar panels 200 wave 201 Swivel movement of the shaft 210 outer shaft part 211 Wave-shaped polygon 212 wave collars 213 spring 220 inner shaft part 221 Nut 300 bearings 400 support 500 drive unit 600 sliding bearing arrangement 610 Plain bearing outer ring 611 Sliding surface 630 inner sliding bearing seal 640 outer sliding bearing seal

Claims

[1] Sliding bearing arrangement (600) comprising an outer ring (610) with a sliding lining (611) in which a shaft (200) is supported, where the shaft (200) is formed in an axial direction into an inner shaft part (220) and at least one outer shaft part (210), wherein the inner shaft part (220) is designed to be supported opposite the outer ring (610) and is sealed against it by an inner sliding bearing seal (630), and the outer shaft part (210) is elastically and positively connected to the outer ring (610) by an outer sliding bearing seal (640). [2] Sliding bearing arrangement (600) according to claim 1, characterized by , that the outer wave part (210) comprises a wave polygon (211) and a wave collar (212) adjoining it, wherein the outer sliding bearing seal (640) is arranged radially circumferentially along an outer circumference of the shaft collar (212). [3] Sliding bearing arrangement (600) according to claim 1 or 2, characterized by , that the outer sliding bearing seal (640) is designed as a multi-lipped seal. [4] Sliding bearing arrangement (600) according to one of claims 1 to 3, characterized by , that the outer sliding bearing seal (640) forms grease deposits. [5] Sliding bearing arrangement (600) according to one of claims 1 to 4, characterized by , that the outer sliding bearing seal (640) is made of polyurethane elastomer. [6] Sliding bearing arrangement (600) according to one of claims 1 to 5, characterized by , that the inner shaft part (220) has at least one groove (221) and the outer shaft part (210) has at least one spring (213), wherein the groove (221) and the spring (213) are complementary and form a positive fit to each other. [7] Sliding bearing arrangement (600) according to one of claims 1 to 6, characterized by, that the shaft (200) is formed in the axial direction into an inner shaft part (220) and two outer shaft parts (210) which are arranged in the axial direction on both sides of the inner shaft part (220). [8] Drive unit for a shaft (200) which is divided in the axial direction into an inner shaft part (220) and at least one outer shaft part (210), characterized by , that the drive unit comprises a sliding bearing arrangement (600) according to one of claims 1 to 7. [9] Tracking system for solar panels comprising a shaft (200) which is divided in the axial direction into an inner shaft part (220) and at least one outer shaft part (210), wherein the shaft (200) is supported in one or more bearings (300) on supports (400) and is fixed to the solar panel (100), wherein the shaft (200) is pivotable by at least one drive unit according to claim 8. [10] Photovoltaic system comprising solar panels (100) with a tracking system according to claim 9.

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