Hollow pipe and device used in semi-direct-drive gearbox

Abstract

The utility model discloses a hollow pipe and a device used in a semi-direct-drive gearbox, which relate to the field of wind power, the structure comprises a pipe body and a connecting section, one end of the connecting section is used for being connected with a variable-pitch slip ring, the other end of the connecting section is connected with the pipe body, the connecting section is connected with a grounding wire, and the grounding wire is grounded. The structure is provided aiming at the induced voltage generated by the hollow pipe of the gear box, and the phenomenon of electrocorrosion of the induced voltage at the position to the half direct-drive gear box is reduced or even avoided.

Description

Technical Field

[0001] This utility model relates to the field of wind power, and in particular to a hollow tube and device used in a semi-direct drive gearbox. Background Technology

[0002] In wind turbine generators, compact semi-direct drive gearboxes are commonly used transmission chains, with their input end connected to the wind turbine shaft and their output end connected to the generator. Electro-corrosion within semi-direct drive gearboxes is a prevalent problem in the industry, generally attributed to shaft voltage during operation. While engineers have implemented various measures to address this issue, such as using filters, common-mode rejection technology, insulated bearings, or grounded carbon brushes, these methods can reduce or even eliminate electro-corrosion caused by shaft current. However, in practice, electro-corrosion still exists within semi-direct drive gearboxes even with these methods. Therefore, further research is needed to investigate the causes and solutions for electro-corrosion in semi-direct drive gearboxes. Utility Model Content

[0003] The purpose of this utility model is to provide a hollow tube and device for use in a semi-direct drive gearbox, which addresses the problems mentioned above. This structure is designed to reduce or even eliminate the electro-corrosion phenomenon caused by the induced voltage generated in the hollow tube of the gearbox.

[0004] Through practical experience, it was discovered that voltage exists on the hollow tubes and connecting flanges in compact semi-direct drive gearboxes. This voltage forms a current loop within the gearbox, leading to bearing galvanic corrosion and gear pitting. The voltage on the hollow tubes is primarily concentrated on the section connecting the pitch slip ring (for simplicity, this section will be referred to as the connecting section). Because this connecting section is closer to the generator interior, and in some cases even partially located within the generator, electromagnetic induction and stray capacitance coupling result in voltage on the connecting section and connecting flange, which are rotating components. The voltage generated is collectively referred to as induced voltage. In a semi-direct drive gearbox, the gears or bearings are in direct or indirect contact with the connecting section and connecting flange. If the induced voltage exceeds the insulation threshold of the oil film at the gear or bearing, partial discharge will occur. The instantaneous high temperature (up to several thousand degrees Celsius) will cause the metal surface to melt and oxidize, forming pitting or pits. The induced voltage generated in the connecting section has a more severe impact. Therefore, the technical solution adopted by this utility model is as follows: a hollow tube used in a semi-direct drive gearbox, including a tube body and a connecting section. One end of the connecting section is used to connect to the pitch slip ring, and the other end of the connecting section is connected to the tube body. The connecting section is connected to a grounding wire, and the grounding wire is grounded.

[0005] Furthermore, the connection segment is grounded via a conductive brush.

[0006] Furthermore, the connecting section is surrounded by a mounting carrier, and the conductive brush is mounted on the mounting carrier.

[0007] Furthermore, a gasket made of insulating material is provided between the pipe body and the connecting section.

[0008] Furthermore, the pipe body and the connecting section are joined together by bolts.

[0009] Furthermore, after the pipe body and the connecting section are bolted together, there is an insulating support sleeve on the bolt thread, and the insulating support sleeve is located in the bolt engagement hole on the pipe body and / or the connecting section for bolt engagement; there is an insulating gasket on the bolt thread, and the insulating gasket is located between the bolt nut and the end face of the pipe body, or / and the insulating gasket is located between the bolt nut and the end face of the connecting section.

[0010] Furthermore, the bolt passes through the washer.

[0011] Furthermore, an insulating sleeve is fitted onto the screw, which covers the portion of the screw not covered by the insulating support sleeve.

[0012] A semi-direct drive gearbox having the aforementioned hollow tube.

[0013] A wind turbine generator set having the aforementioned semi-direct drive gearbox.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0015] The key feature of this invention is to solve the technical problem of "the induced voltage generated by the connecting section on the hollow tube forming a current loop in the semi-direct drive gearbox, leading to bearing electro-erosion and gear pitting". By grounding the connecting section, the induced voltage generated by the connecting section in the changing electromagnetic field is conducted away, thereby preventing the formation of a high-voltage current loop in the semi-direct drive gearbox and further reducing or even eliminating the electro-erosion phenomenon in the semi-direct drive gearbox. Attached Figure Description

[0016] This utility model will be described by way of example and with reference to the accompanying drawings, wherein:

[0017] Figure 1 This is a schematic diagram of the hollow tube structure;

[0018] Figure 2 This is an assembly diagram of the pad, insulating pad, and insulating support sleeve;

[0019] Figure 3 This is a schematic diagram of the conductive brush assembly.

[0020] The markings in the diagram are: 1-pipe body; 2-connecting section; 3-gasket; 4-conductive brush; 5-bolt; 51-nut; 52-screw; 61-insulating gasket; 62-insulating sleeve; 63-insulating support sleeve; 7-mounting carrier. Detailed Implementation

[0021] In the description of this specification, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this specification and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification.

[0022] Furthermore, the use of terms such as "horizontal" or "vertical" in this specification does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0023] In the description of this specification, it should also be noted that, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” should be interpreted broadly. For example, a link can be a fixed link, a detachable link, or an integral link; it can be a mechanical link or an electrical link; it can be a direct link or an indirect link through an intermediate medium; it can be a connection within two components.

[0024] Example 1

[0025] like Figures 1-3 As shown, a hollow tube used in a semi-direct drive gearbox includes a tube body 1 and a connecting section 2. One end of the connecting section 2 is connected to a pitch slip ring, and the other end of the connecting section 2 is connected to the tube body 1. The connecting section 2 is connected to a grounding wire, which is grounded. To solve the technical problem of "the induced voltage generated by the connecting section 2 on the hollow tube forming a current loop in the semi-direct drive gearbox, leading to bearing electrolytic corrosion and gear pitting," the connecting section 2 is grounded through a grounding wire. This allows the induced voltage generated by the connecting section 2 in the changing electromagnetic field to be conducted away, thereby preventing the formation of a high-voltage current loop in the semi-direct drive gearbox and further reducing or even eliminating electrolytic corrosion in the semi-direct drive gearbox.

[0026] It should be noted that connection section 2 can be grounded by connecting to a grounding wire, or it can be connected to the rotor of the generator by a wire. The rotor of the generator is electrically connected to a grounding wire, which is grounded (this also exists in the prior art, and those skilled in the art are aware of this, so it will not be described in detail here). This way, while meeting the grounding requirements, the occurrence of too many cables can be avoided, making it suitable for compact environments.

[0027] It should be noted that the structure disclosed in this embodiment does not make any changes to the structure of the tube body 1 and the connecting section 2. Therefore, the connection between the connecting section 2, the tube body 1 and the pitch slip ring and other components remains unchanged. The specific structure is known to those skilled in the art. Therefore, it is described in detail in this specification.

[0028] In one optional implementation, the connecting section 2 is grounded through a conductive brush 4, which can be either a conductive brush or a carbon brush. The conductive brush 4 prevents the grounding wire or cable from getting tangled when the hollow tube rotates around its own axis, and also ensures the stability of the induced voltage conduction.

[0029] In one feasible implementation, a mounting carrier 7 is provided around the connecting section 2, and the conductive brush 4 is disposed on the mounting carrier 7, maintaining contact with the connecting section 2 to ensure that the conductive brush 4 does not affect the normal operation of the generator and the stable conduction voltage after installation. Optionally, the mounting carrier 7 can be located at positions such as the pitch slip ring, generator rotor, or generator end cover.

[0030] In one optional embodiment, a gasket 3 made of insulating material is provided between the pipe body 1 and the connecting section 2. When the connecting section 2 generates an induced voltage, the blocking effect of the non-conductive gasket 3 prevents this induced voltage from forming a closed electrical circuit within the semi-direct drive gearbox. This prevents the metal surface from melting or oxidizing due to the induced voltage within the semi-direct drive gearbox, further reducing or even eliminating electro-corrosion. Furthermore, based on the design of the gasket 3, the grounding wire, whether directly connected or connected through the generator rotor, has inherent resistance, and due to the long cable length, this resistance is high. Therefore, the induced voltage generated by the connecting section 2 cannot be completely conducted away, only reduced. By providing the gasket 3, the formation of a closed electrical circuit within the semi-direct drive gearbox by the induced voltage on the connecting section 2 can be completely prevented, even if a residual induced voltage exists.

[0031] In one optional embodiment, the pipe body 1 and the connecting section 2 are connected by bolts 5 to achieve a detachable connection, which facilitates maintenance.

[0032] One possible specific implementation, such as Figure 2As shown, after the pipe body 1 and the connecting section 2 are engaged with bolt 5, an insulating support sleeve 63 is fitted onto the threaded rod 52 of bolt 5, and the insulating support sleeve 63 is located in the engagement hole on the pipe body 1 and / or the connecting section 2 for the bolt 5 to engage; an insulating gasket 61 is fitted onto the threaded rod 52 of bolt 5, and the insulating gasket 61 is located between the nut 51 of bolt 5 and the end face of pipe body 1, or / and the insulating gasket 61 is located between the nut 51 of bolt 5 and the end face of connecting section 2; both the insulating gasket 61 and the insulating support sleeve 63 are made of insulating material, and the insulating support sleeve 63 supports the threaded rod 52, so that the threaded rod 52 and the pipe body 1 are engaged. A gap is formed between the screw 52 and the inner wall of the engagement hole on the connecting section 2, thereby preventing the screw 52 from contacting the tube body 1 and / or the connecting section 2. At the same time, the insulating gasket 61 can also prevent the nut 51 from contacting the end face of the tube body 1 and / or the connecting section 2. In summary, by using the insulating gasket 61 and the insulating support sleeve 63 together, the screw 52 and nut 51 in the bolt 5 can be effectively isolated from contact with the tube body 1, thereby achieving the purpose of isolating electrical connection and effectively preventing the induced voltage on the connecting section 2 from being electrically connected to the tube body 1 through the bolt 5. On the other hand, this design of the insulating gasket 61 and the insulating support sleeve 63 also facilitates installation and disassembly.

[0033] In one feasible implementation, the screw 52 of the bolt 5 passes through the washer 3, so that the washer 3 can be supported by the screw 52, ​​thereby improving the positional stability of the washer 3.

[0034] In one feasible implementation, the outer diameter of the insulating support sleeve 63 matches the inner diameter of the engagement hole, and the inner diameter of the insulating support sleeve 63 matches the diameter of the screw 52. This method ensures that after the insulating support sleeve 63 is made into the screw 52, ​​the axis of the screw 52 is collinear with the axis of the engagement hole. On the one hand, this improves the stability of the structure and avoids positional fluctuations; on the other hand, it avoids the situation where a certain position is too close, causing voltage breakdown of the air and resulting in failure of the electrical connection.

[0035] Furthermore, the insulating gasket 61 and the insulating support sleeve 63 are integrally formed, forming a sleeve-shaped structure with a T-shaped cross section. This structure can use the end face of the insulating gasket 61 as the positioning surface, which can effectively improve the dimensional accuracy for the coaxial installation of the insulating support sleeve 63.

[0036] In one feasible implementation, as described above, although there is a gap between the screw 52 and the inner wall of the engagement hole under the action of the insulating support sleeve 63, there is still a possibility that the air in the gap may be broken down due to excessive voltage. In order to prevent this from happening, and to ensure the effect of isolating the screw 52 and nut 51 in the isolation bolt 5 from the output end of the gearbox; or / and to ensure the effect of isolating the screw 52 and nut 51 in the isolation bolt 5 from the tube body 1, so as to avoid the induced voltage generated at the connecting flange from conducting with the output end of the gearbox, or / and to avoid the induced voltage generated at the connecting section 2 from conducting with the tube body 1, a further design is that the screw 52 is also fitted with an insulating sleeve 62, which covers the part of the screw 52 that is not covered by the insulating support sleeve 63.

[0037] Further design allows the insulating support sleeve 63 to be integrally formed with the insulating sleeve 62.

[0038] Example 2

[0039] A semi-direct drive gearbox having the hollow tube described in Example 1.

[0040] It should be noted that the structure of the semi-direct drive gearbox is known to those skilled in the art, and the assembly of the hollow tube 1 and the remaining structure of the semi-direct drive gearbox will not be described in detail in this specification.

[0041] Example 3

[0042] A wind turbine generator set having the semi-direct drive gearbox described in Example 2.

[0043] It should be noted that the structure of the wind turbine generator set is known to those skilled in the art, and the assembly of the semi-direct drive gearbox and the remaining structure of the semi-direct drive gearbox will not be described in detail in this specification.

[0044] This invention is not limited to the specific embodiments described above. This invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A hollow tube used in a semi-direct drive gearbox, characterized in that: It includes a tube body (1) and a connecting section (2). One end of the connecting section (2) is used to connect to the pitch slip ring, and the other end of the connecting section (2) is connected to the tube body (1). The connecting section (2) is connected to a grounding wire, which is grounded.

2. The hollow tube according to claim 1, characterized in that: The connecting section (2) is grounded through a conductive brush (4).

3. The hollow tube according to claim 2, characterized in that: The connecting segment (2) is surrounded by a mounting carrier (7), and the conductive brush (4) is mounted on the mounting carrier (7).

4. The hollow tube according to claim 1, characterized in that: A gasket (3) made of insulating material is provided between the pipe body (1) and the connecting section (2).

5. The hollow tube according to claim 4, characterized in that: The pipe body (1) and the connecting section (2) are connected by bolts (5).

6. The hollow tube according to claim 5, characterized in that: After the pipe body (1) and the connecting section (2) are engaged by the bolt (5), there is an insulating support sleeve (63) on the thread (52) of the bolt (5), and the insulating support sleeve (63) is located in the engagement hole on the pipe body (1) and / or the connecting section (2) for the bolt (5) to engage; there is an insulating gasket (61) on the thread (52) of the bolt (5), and the insulating gasket (61) is located between the nut (51) of the bolt (5) and the end face of the pipe body (1), or / and the insulating gasket (61) is located between the nut (51) of the bolt (5) and the end face of the connecting section (2).

7. The hollow tube according to claim 6, characterized in that: The bolt (5) passes through the washer (3).

8. The hollow tube according to claim 6, characterized in that: An insulating sleeve (62) is also fitted on the screw (52), which covers the part of the screw (52) that is not covered by the insulating support sleeve (63).

9. A semi-direct drive gearbox, characterized in that: The semi-direct drive gearbox has a hollow tube as described in any one of claims 1-8.

10. A wind turbine generator set, characterized in that: The wind turbine has the semi-direct drive gearbox as described in claim 9.

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