Solar rotation device with vibration-resistant structure

Abstract

The present invention discloses a solar rotation device having a vibration-resistant structure, which includes a first planetary gear set and a second planetary gear set arranged in the next stage of the first planetary gear set, and in which at least the outer peripheral surfaces of the second PL gear and second ring gear of the second planetary gear set have an inclined tooth profile formed thereon, thus forming a tapered structure.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2022-0006224, filed on January 14, 2022, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings thereof. The present invention relates to a solar rotation device having a vibration-resistant structure, and more particularly to a solar rotation device having a vibration-resistant structure that is attached to a pole and provides a rotational force to a solar panel. [Background technology]

[0002] Generally, a solar power generation system is constructed in the form of an aggregation of a large number of solar panels on a site such as forest land, fallow land, the roof of a building, a reservoir, or a salt field. When the site for a solar power generation plant is a forest or farmland, the site must be leveled by cutting trees and carrying out civil engineering work before the frame structure and solar panels can be installed, which inevitably results in environmental damage, resulting in large-scale damage to trees and soil. Due to these side effects, it is difficult to use forests and farmland as a site for a solar power generation plant, even if they meet the site requirements for solar power generation. Patent Document 1 discloses a self-weight type solar power generation device that can be installed in a non-destructive manner on a building rooftop, embankment, etc. The self-weight type solar power generation device includes a pole assembly formed by connecting at least one pole continuously, and a light collecting plate attached to the top of the pole assembly, and the pole is provided with an inclined surface on the top surface and a filler receiving space inside for receiving a filler. Patent Document 2 relates to a method for installing solar modules without occupying rice fields, and discloses a solar module and method for installing in rice fields that includes a lower support base, an installation and fixing frame, and a support frame so that the solar module can be easily installed in fields that are off-farm after harvest. Patent Document 2 also discloses a solar module having a structure in which multiple easy-to-install solar modules are stacked and connected to the installation and fixing frame of one easy-to-install solar module and one side of the protective frame of another easy-to-install solar module by hinge means, and can be spread out and installed when in use. However, conventional solar power generation systems require a large area for the frame structure that supports the solar panels, and there remains the problem of serious natural damage occurring during construction, so alternative solutions are needed. In addition, conventional solar power generation systems have the disadvantage of low solar power generation efficiency because the solar panels are usually fixed in place. Although systems that track the movement of the sun and move the solar panels have been released for solar power generation, the devices are complex and expensive, making it difficult to build the system. In order to increase the efficiency of solar power generation, it is preferable to rotate the solar panel along a predetermined path taking into account the amount of sunlight. However, if the solar panel is placed at the top of a pole and the rotating shaft of the drive motor is simply connected to the solar panel to rotate it, the rotating shaft of the drive motor may be overloaded, and when external forces such as wind are applied, the connection between the rotating shaft and the solar panel may become misaligned or damaged, causing wiring to break at the rotating part. Therefore, measures to address these problems are required. In addition, when external force such as wind is applied to the solar panel, backlash in the gear assembly installed between the drive motor and the solar panel can cause the solar panel to vibrate, and in severe cases, the gear assembly can be damaged, causing the solar panel to tip over. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Korean Patent Publication No. 2011-0024887 [Patent Document 2] Korean Patent Publication No. 2016-0086729 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention was devised in consideration of the above-mentioned problems, and aims to provide a solar rotation device with a vibration-resistant structure that can prevent the occurrence of unnecessary backlash in the gear assembly provided in the rotation device. Another object of the present invention is to provide a solar rotating device with a vibration-resistant structure that can solve the problem of wiring being broken in the rotating part when the connecting parts between the rotating device and the solar panel are displaced or damaged due to external forces such as wind. [Means for solving the problem]

[0005] In order to achieve the above object, one aspect of the present invention is a solar panel array solar panel ... a second planetary gear set disposed next to the first planetary gear set to receive rotational force, the second planetary gear set comprising a second sun gear, a plurality of second PL gears disposed at predetermined intervals around the second sun gear and meshed therewith, and a second ring gear meshed with the outer sides of the plurality of second PL gears and outputting reduced rotational force to the first tubular body, wherein at least the peripheral surfaces of the second PL gear and the second ring gear have inclined teeth formed thereon to form a tapered structure. It is preferable that the inclined tooth profile is formed on all of the outer peripheral surface of the second sun gear, the outer peripheral surface of the second PL gear, and the inner peripheral surface of the second ring gear, so that a predetermined clearance is secured at the gear contact surfaces during rotation, and that the tapered structure allows the gears to mesh tightly with each other at the end of rotation, preventing backlash. When the rotation is completed, a force may be applied to the second PL gears due to their own weight in a direction in which they are inserted into the second sun gear and the second ring gear. The first ring gear and the second ring gear may each comprise an assembly of an upper ring gear and a lower ring gear. By connecting the first ring gear to the second sun gear, or by connecting the first ring gear to a portion of the carrier of the second PL gear, rotational force can be transmitted from the first planetary gear set to the second planetary gear set. Another aspect of the present invention provides a multi-stage compound gear assembly for a solar rotation device, comprising: a first planetary gear set including a first sun gear that receives rotational force generated by a drive motor, a plurality of first PL gears arranged at predetermined intervals around the first sun gear and meshed therewith, and a first ring gear meshed on the outside of the plurality of first PL gears; and a second planetary gear set that is arranged next to the first planetary gear set to receive rotational force, and includes a second sun gear, a plurality of second PL gears arranged at predetermined intervals around the second sun gear and meshed therewith, and a second ring gear meshed on the outside of the plurality of second PL gears and outputting reduced rotational force, wherein at least the peripheral surfaces of the second PL gear and the second ring gear have inclined teeth formed thereon, giving them a tapered structure. [Effects of the Invention]

[0006] The solar rotation device having a vibration-resistant structure according to one aspect of the present invention has the following effects. First, the multi-stage compound gear assembly ensures a sufficient reduction ratio and generates the appropriate clearance (backlash) required for rotation at the contact surfaces between the gears. When rotation is complete, the second PL gear, second sun gear, and second ring gear come into tight contact with each other due to their tapered structure, preventing backlash from occurring, thereby preventing vibration and shaking of the solar panel due to wind, etc. By providing a second bearing and an assembly of the first tubular body and the second tubular body, the solar panel array attached to the pole can be firmly supported and rotational force can be transmitted stably without shaking due to external forces such as various vibrations and wind. Third, even if the diameters of the first and second tubular bodies are designed to be the same as or similar to the diameter of the pole, smooth rotation is achieved by the bearings interposed between the first and second tubular bodies, allowing precise rotation control in seconds. Fourth, since the rotation device can be miniaturized and the configuration is simple, the investment can be recovered quickly and the problems of frequent breakdowns and high costs, which are disadvantages of conventional solar tracking devices, can be solved. Fifth, because the solar panels are supported by poles, they are sufficiently separated from the ground and allow for smooth ventilation, which helps prevent the temperature of the solar panels from rising and improves the efficiency of solar power generation. Sixth, if the solar power generation site is in a mountainous area or forest, trees around the poles supporting the solar panels can be left as they are, minimizing natural damage. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a rear perspective view showing the appearance of a solar rotation device having a vibration-resistant structure according to a preferred embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a partially enlarged view of the rotation device shown in FIG. [Figure 3] FIG. 3 is an exploded perspective view showing the internal configuration of the rotation device shown in FIG. 2. [Figure 4] 4 is a perspective view showing a part of the gear unit and the drive motor shown in FIG. 3 in a cutaway view. FIG. [Figure 5] FIG. 5 is a partial cross-sectional view showing the configuration of a gear portion shown in FIG. 4. [Figure 6] FIG. 6 is a cross-sectional view showing a modified embodiment of FIG. 5. [Figure 7] FIG. 6 is a cross-sectional view showing a modified embodiment of FIG. 5. [Figure 8] FIG. 6 is a cross-sectional view showing a modified embodiment of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0008] FIG. 1 is a rear perspective view showing the appearance of a solar rotation device having a vibration-resistant structure according to a preferred embodiment of the present invention, FIG. 2 is a partially enlarged view of the rotation device shown in FIG. 1, FIG. 3 is an exploded perspective view showing the internal configuration of the rotation device shown in FIG. 2, and FIG. 4 is a perspective view showing a portion of the gear unit and drive motor configuration shown in FIG. 3 with a cutaway view.

[0009] 1 to 4, a solar rotation device 100 having a vibration-resistant structure according to a preferred embodiment of the present invention includes a first tubular body 101 connected to the back surface of a solar panel array 15, a second tubular body 106 assembled to the lower part of the first tubular body 101 and having its lower end fixed to a pole 10, a drive motor 107 attached to the inside of the second tubular body 106 to provide rotational force to the first tubular body 101, and a gear unit 109 that transmits the rotational force provided by the drive motor 107 to the first tubular body 101. Preferably, the solar rotation device 100 includes contact units 102, 103, and 104 having at least three contact points attached to the joining portion between the first tubular body 101 and the second tubular body 106. The solar panel array 15 is configured by connecting a plurality of solar panels 15a in series with each other. The solar panel array 15 is attached to an inclined surface formed at the upper end of the first tubular body 101, and is installed so as to be inclined with respect to the ground. The installation angle of the solar panel array 15 is determined according to the angle of the inclined surface. The pole 10 is installed vertically to the ground, and its lower end is fixed to the ground by fastening means such as an anchor bolt, etc. Preferably, the pole 10 is a metal tubular body with a round outer periphery, like a typical street light pole, but may be made of various other materials and shapes. The first tubular body 101 is a pipe-shaped structure having a circular peripheral surface and a waterproof cover 105 provided on its inclined upper surface. The waterproof cover 105 is detachably fastened so that the internal space of the first tubular body 101 can be opened and closed. The second tubular body 106 is a pipe-shaped structure with a circular peripheral surface, assembled so as to be located below the first tubular body 101. A space is provided at the lower end of the second tubular body 106 into which the upper end portion of the pole 10 can be fitted. By fitting the pole 10 into the space, the second tubular body 106 is fixed to the upper end of the pole. In order to enhance the connection between the rotating device 100 and the pole 10 and to form a structurally stable assembly, the diameters of the first tubular body 101 and the second tubular body 106 can be designed to be the same as or similar to the diameter of the pole. Between the first tubular body 101 and the second tubular body 106, a gear portion 109 including a predetermined bearing (see reference numeral 116 in FIG. 5) is interposed. The gear unit 109, which reduces the rotational force provided by the drive motor 107 at a sufficient ratio and transmits it to the first tubular body 101, is composed of a multi-stage compound gear assembly including at least two planetary gear sets. Hereinafter, the configuration of the invention will be described focusing on an embodiment in which the gear unit 109 is composed of an assembly of two planetary gear sets. The gear unit 109 includes a first planetary gear set that receives rotational force from the rotary shaft of the drive motor 107, and a second planetary gear set that is assembled after the first planetary gear set. If the gear unit 109 includes three or more planetary gear sets, an additional planetary gear set is disposed before the first planetary gear set.

[0010] 4 and 5, the first planetary gear set includes a first sun gear 110 that is substantially connected to the rotary shaft of the drive motor 107 and receives rotational force therefrom, a plurality of first PL gears 111 that are arranged at predetermined intervals around the first sun gear 110 and mesh with the first sun gear 110, a first ring gear 112 that is arranged outside the plurality of first PL gears 111 and meshes with the first PL gears 111, and a motor cover 117 that encloses the first ring gear 112. Here, if the gear unit 109 includes a planetary gear set with, for example, three or more stages, a ring gear (not shown) of another planetary gear set located in front of the first planetary gear set may be connected to the first sun gear 110 to transmit rotational force thereto. The second planetary gear set includes a second sun gear 113 connected to the first ring gear 112 to receive rotational force, a plurality of second PL gears 114 spaced apart around the second sun gear 113 and meshing therewith, a second ring gear 115 meshing with the outer surfaces of the second PL gears 114 and fixed to the first tubular body 101, and a cross roller bearing 116 disposed within the second ring gear 115. A portion of the lower end of the second sun gear 113 is fitted and fixed to the first ring gear 112 and rotates integrally with the first ring gear 115 to receive rotational force. Alternatively, a portion (e.g., a carrier pin) of a carrier 118 supporting the plurality of second PL gears 114 may be connected to the first ring gear 112 to receive rotational force. In this case, a variant in which the second sun gear 113 is omitted is also possible. Both the first ring gear 112 and the second ring gear 115 may be comprised of an assembly of an upper ring gear 112a, 115a and a lower ring gear 112b, 115b. Since the second planetary gear set outputs reduced rotational force to the first tubular body 101, at least the second PL gear 114 and the second ring gear 115 have inclined teeth formed on their peripheral surfaces to form a tapered structure (see the oval in FIG. 5). Most preferably, as shown in FIGS. 4 and 5, the outer peripheral surface of the second sun gear 113, the outer peripheral surface of the second PL gear 114, and the inner peripheral surface of the second ring gear 115 all have inclined teeth formed at a predetermined pitch along the outer periphery to form a tapered structure. That is, the second sun gear 113 has a relatively narrow upper cross section and a relatively wide lower cross section, and the second PL gear 114 has a relatively wide upper cross section and a relatively narrow lower cross section. Furthermore, the upper part of the second ring gear 115 has a relatively wide inner diameter, and the lower part of the second ring gear 115 has a relatively narrow inner diameter corresponding to the peripheral surface of the second PL gear 114. In this case, the second sun gear 113 is composed of a tapered first portion and a non-tapered second portion that is fitted and fixed to the first ring gear 115. Good . With this tapered structure, when the planetary gear set rotates, a predetermined clearance necessary for smooth rotation is ensured between the contact surfaces of the second sun gear 113, the second PL gear 114, and the second ring gear 115. When rotation ends, the gears (second sun gear 113, second PL gear 114, and second ring gear 115) return to their original positions due to their own weight, and the tapered structure allows them to closely mesh with each other, effectively preventing unnecessary backlash. A spring may be added to one side of the gear portion 109 to apply elastic force so that the gears (second sun gear 113, second PL gear 114, and second ring gear 115) can return more quickly when rotation ends. The tapered structure as described above is formed at least at the contact portion between the second PL gear 114 and the second ring gear 115, which has the effect of preventing the rotating device 100 from vibrating due to external forces such as wind. If the second sun gear 113 also has a tapered structure, the second PL gear 114 is stably supported by the second sun gear 113 located at its center, which makes it possible to more effectively prevent the rotating device from vibrating due to external forces. If a predetermined backlash of several millimeters is required on the contact surfaces between the gears (second sun gear 113, second PL gear 114, second ring gear 115) during rotation of the second planetary gear set, the plurality of second PL gears 114 move slightly upward while overcoming their own weight due to the rotational force, thereby ensuring the backlash necessary for smooth rotation. Meanwhile, when the rotation of the second planetary gear set ends, the plurality of second PL gears 114 return downward to their original positions due to their own weight, and because they are tightly meshed with the second sun gear 113 and second ring gear 115 due to their tapered structure, the rotating device 100 is prevented from shaking due to external forces such as wind, and therefore shaking of the solar panel array 15 can be prevented.

[0011] According to a modified embodiment of the present invention, various combinations of gears having a tapered structure among the second sun gear 113, the second PL gear 114, and the second ring gear 115 may be used. Specifically, as shown in Fig. 6, the inclined teeth forming the tapered structure may be formed only on the outer circumferential surface of the second PL gear 114 and the inner circumferential surface of the second ring gear 115, and the outer circumferential surface of the second sun gear 113 may have a non-tapered tooth profile. In this case, the upper second ring gear 115a and the lower second ring gear 115b constituting the second ring gear 115 have different inner diameters corresponding to the inclined surface of the second PL gear 114. As another variation, the inclined tooth profile forming the tapered structure may be formed only on the inner peripheral surface of the second ring gear 115 as shown in FIG. 7, and the second sun gear 113 and the second PL gear 114 may be configured to have non-tapered tooth profiles. As yet another variation, the inclined tooth profile forming the tapered structure may be formed only on the outer peripheral surface of the second PL gear 115 as shown in FIG. 8, and the second sun gear 113 and the second ring gear 115 may be configured to have non-tapered tooth profiles. The drive motor 107 is fixedly installed upright inside the second tubular body 106 , preferably coaxially with the second tubular body 106 , and provides a rotational force to the gear portion 109 .

[0012] Further referring to Figure 3, a first contact 102, a second contact 103, and a third contact 104 for transmitting power and / or signals are provided at or around the joining portion or contact portion between the first tubular body 101 and the second tubular body 106. Although not shown, according to a variant of the present invention, a rotating device having more than three contacts may also be provided. The first contact 102 and the second contact 103 are each composed of a contact pair consisting of conductor rings 102a, 103a fixed so as to be substantially connected to the second tubular body 106, and conductor blocks 102b, 103b that slide against the upper surfaces of the conductor rings 102a, 103a to maintain continuous contact during relative rotation between the first tubular body 101 and the second tubular body 106. The conductor ring 102a of the first contact 102 and the conductor ring 103a of the second contact 103 are arranged concentrically with each other. One of the first contact 102 and the second contact 103 is a negative terminal, and the other is a positive terminal. Both ends of the entire output section of the multiple solar panels 15a are connected to the first contact 102 and the second contact 103, respectively. The power output through the first contact 102 and the second contact 103 is supplied to a power generation inverter 108 and used for power generation. The third contact 104 is composed of a contact pair consisting of a conductor ring 104a that is fixed to the rotating portion of the gear unit 109 above the first contact 102 and the second contact 103 and rotates integrally with the first tubular body 101, and a conductor block 104b that slides against the lower surface of the conductor ring 104a and maintains contact when the first tubular body 101 and the second tubular body 106 rotate relative to each other. The third contact 104 is electrically connected to a positive terminal drawn from a portion of the output section (e.g., the output end of one solar panel 15a) of the multiple solar panels 15a that make up the solar panel array 15. The power output through the third contact 104 is used as a power source for driving the drive motor 107 and a predetermined PCB (Printed Circuit Board). The third contact 104 is preferably positioned relatively radially inward from the rotation axis of the rotating device, i.e., closer to the drive motor 107, than the second contact 103, to supply power to the drive motor 107 and the PCB. The first contact 102 is preferably used as a negative common terminal for the second contact 103 and the third contact 104. The electrical polarities given to the first contact 102, the second contact 103 and the third contact 104 are not limited to the above-described embodiment, and may of course be variously modified. The solar rotation device 100 configured as described above rotates the first tubular body 101 by providing the rotational force of the drive motor 107 to the gear unit 109, thereby gradually rotating the solar panel array 15 fixed to the upper end of the first tubular body 101. The first tubular body 101 rotates relative to the second tubular body 106 fixed to the pole 10 while stably supporting the solar panel 15a. Bearings are interposed between the first tubular body 101 and the second tubular body 106, providing structural stability and enabling smooth rotation. The rotation path of the solar panel 15a is preferably set to maximize exposure to the sun, taking into account the amount of solar radiation. By rotating the solar panel 15a at a constant speed for a predetermined period of time, the amount of solar power generated can be increased compared to when the solar panel 15a is placed stationary and facing in one direction, without the need for a separate solar tracking device with a complex structure. Furthermore, in addition to the solar panel array 15, the present invention may also be equipped with an elevating lighting unit and an elevating CCTV (Closed Circuit Television) camera unit. In this case, the lighting unit and the CCTV camera unit are raised by winding up the first and second lifting cords as the drums built into the main body of each unit are rotated in the forward direction. When the lighting unit and the CCTV camera unit are connected to their respective main bodies located at the top of the pole 10, the upper and lower contacts built into the main bodies come into contact with each other, thereby supplying power to the lighting unit and the CCTV camera unit. Here, power for driving the lighting unit and the CCTV camera unit may be provided, for example, through the first contact.

[0013] In the solar rotation device 100 according to the present invention, the rotational force generated by the drive motor 107 during operation rotates the first tubular body 101 through the gear unit 109, causing the solar panel array to rotate gradually. The first tubular body 101 rotates relative to the second tubular body 106 fixed to the pole, while stably supporting the solar panel array. The gear unit 109 is composed of a planetary gear set including a first planetary gear set and a second planetary gear set, and reduces the rotational force of the drive motor 107 and outputs it to the first tubular body 101. The first tubular body 101 rotates integrally with the solar panel array 15 fixed to its upper surface. The rotational force of the drive motor 107 is transmitted in a chain reaction to the first planetary gear set and the second planetary gear set. During rotation of the second planetary gear set, a predetermined clearance necessary for smooth rotation is ensured between the contact surfaces of the second sun gear 113, the second PL gear 114, and the second ring gear 115. When rotation is completed, the gears return to their original positions under their own weight, and the tapered structure allows them to closely mesh with each other, preventing unwanted backlash. While it is most preferable to form the tapered structure on all of the second sun gear 113, the second PL gear 114, and the second ring gear 115, the effect of reducing unwanted backlash can be achieved even if only the second PL gear 114 and the second ring gear 115 are formed with the tapered structure. The assembly in which the assembly of the first tubular body 101 and the second tubular body 106 is coupled to the solar panel 15a can transmit rotational force more stably than the conventional technology in which the rotational shaft of the drive motor is simply connected to the solar panel and rotated, because the diameters of the first tubular body 101 and the second tubular body 106 are larger than the diameter of the rotational shaft of the drive motor 107. In other words, even if external forces such as vibrations generated by the drive motor or wind are applied, the rotational force of the drive motor can be transmitted to the solar panel 15a without error.

[0014] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims. [Industrial Applicability]

[0015] When the present invention is applied, solar power generation can be performed with high efficiency by stably rotating the solar panel attached to the upper end of the pole.

Claims

1. A solar rotation device having a vibration-resistant structure that is attached to the upper end of a pole and rotates a solar panel array, a first tubular body coupled to the solar panel array; a second tubular body coupled to a lower portion of the first tubular body and fixed to an upper end of a pole; a gear unit including at least two planetary gear sets for transmitting reduced rotational force to the first tubular body; a drive motor fixed inside the second tubular body to provide rotational force to the gear portion, The gear portion is a first planetary gear set including a first sun gear receiving a rotational force generated by the drive motor, a plurality of first PL gears arranged at predetermined intervals around the periphery of the first sun gear and meshing with the first sun gear, and a first ring gear meshing with the outer sides of the plurality of first PL gears; a second planetary gear set disposed next to the first planetary gear set to receive the rotational force, the second planetary gear set including a second sun gear, a plurality of second PL gears disposed at predetermined intervals around the periphery of the second sun gear and meshed therewith, and a second ring gear meshed with the outer sides of the plurality of second PL gears to output a reduced rotational force to the first tubular body; an outer peripheral surface of the second sun gear, an outer peripheral surface of the second PL gear, and an inner peripheral surface of the second ring gear all have inclined teeth formed thereon to form a tapered structure; the second sun gear has a relatively narrow upper cross section and a relatively wide lower cross section; the second PL gear has a relatively wide upper cross section and a relatively narrow lower cross section; an upper portion of the second ring gear has a relatively wide inner diameter, and a lower portion of the second ring gear has a relatively narrow inner diameter corresponding to a peripheral surface of the second PL gear; The second PL gears rise slightly during gear rotation to ensure backlash between the second sun gear and the second PL gear, and between the second ring gear and the second PL gear, and at the end of rotation, the second PL gears descend to tightly mesh with the second sun gear and the second ring gear, preventing backlash from occurring. A solar rotation device with vibration-resistant structure.

2. 2. The solar rotation device having a vibration-resistant structure as described in claim 1, wherein when rotation is completed, a force is applied to the plurality of second PL gears by their own weight in a direction in which they are inserted into the second sun gear and the second ring gear.

3. The solar rotation device having a vibration-resistant structure according to claim 1 , wherein the first ring gear and the second ring gear each comprise an assembly of an upper ring gear and a lower ring gear.

4. 2. A solar rotation device having a vibration-resistant structure as described in claim 1, wherein the first ring gear and the second sun gear are connected together, or the first ring gear and a part of the carrier of the second PL gear are connected together, thereby transmitting rotational force from the first planetary gear set to the second planetary gear set.

5. 1. A multi-stage compound gear assembly for a solar rotation device for rotating a solar panel array, comprising: a first planetary gear set including a first sun gear that receives a rotational force generated by a drive motor, a plurality of first PL gears that are arranged at predetermined intervals around the periphery of the first sun gear and mesh with the first PL gears, and a first ring gear that meshes with the outer sides of the plurality of first PL gears; a second planetary gear set disposed next to the first planetary gear set to receive rotational force, the second planetary gear set including a second sun gear, a plurality of second PL gears disposed at predetermined intervals around the periphery of the second sun gear and meshed therewith, and a second ring gear meshed with the outer sides of the plurality of second PL gears to output reduced rotational force; an outer peripheral surface of the second sun gear, an outer peripheral surface of the second PL gear, and an inner peripheral surface of the second ring gear all have inclined teeth formed thereon to form a tapered structure; the second sun gear has a relatively narrow upper cross section and a relatively wide lower cross section; the second PL gear has a relatively wide upper cross section and a relatively narrow lower cross section; an upper portion of the second ring gear has a relatively wide inner diameter; a lower portion of the second ring gear having a relatively narrow inner diameter corresponding to a peripheral surface of the second PL gear; The second PL gears rise slightly during gear rotation to ensure backlash between the second sun gear and the second PL gear, and between the second ring gear and the second PL gear, and at the end of rotation, the second PL gears descend to tightly mesh with the second sun gear and the second ring gear, preventing backlash from occurring. Multi-stage compound gear assembly for solar rotating device.

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