Method for solving electro-corrosion problem of semi-direct-drive gearbox

Abstract

The invention discloses a method for solving electro-corrosion of a semi-direct-drive gearbox, which relates to the field of wind power, and is characterized in that a section, connected with a variable-pitch slip ring, of a hollow pipe is used as a connecting section, the connecting section is grounded, and a connecting flange for connecting the output end of the gearbox and a rotor of a generator is made of a non-conductive material; or a gasket is additionally arranged between a connecting flange for connecting the output end of the gear box and the rotor of the generator and the output end of the gear box, and the gasket is made of an insulating material; according to the method, measures are provided for the induced voltage generated by a hollow pipe of the gearbox and the induced voltage generated by a connecting flange for connecting the gearbox and a rotor of a generator, and the phenomenon of electrocorrosion of the induced voltage at the positions to the half direct drive gearbox is reduced or even eradicated.

Description

Technical Field

[0001] The present invention relates to the field of wind power, and in particular to a method for solving the problem of electrical corrosion in a semi-direct drive gearbox. Background Art

[0002] In wind turbines, compact semi-direct-drive gearboxes currently use a common drive chain, with the input connected to the rotor shaft and the output connected to the generator. Electrocorrosion within semi-direct-drive gearboxes is a common problem in the industry, generally believed to be caused by shaft voltage during operation. Numerous measures have been implemented to address this issue, such as employing filters, common-mode suppression technology, and the use of insulated bearings or grounded carbon brushes. While these methods can reduce or even prevent electrocorrosion caused by shaft current, in practice, electrocorrosion still persists in semi-direct-drive gearboxes, even with these methods. Further research is needed into the causes and solutions for electrocorrosion in semi-direct-drive gearboxes. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for solving the above-mentioned problems and solving the electro-corrosion problem of a semi-direct-drive gearbox. The method proposes measures to reduce or even eliminate the electro-corrosion phenomenon in the semi-direct-drive gearbox caused by the induced voltage generated by the hollow tube of the gearbox and the induced voltage generated by the connecting flange connecting the gearbox and the rotor of the generator.

[0004] After practice, it was found that there was voltage on the hollow tube and the connecting flange in the compact semi-direct drive gearbox. The voltage formed a current loop in the semi-direct drive gearbox, which led to the problems of bearing electrocorrosion and gear pitting. The voltage on the hollow tube was mainly connected to the section of the pitch slip ring (for the convenience of explanation, the section of the hollow tube connected to the pitch slip ring is referred to as the connecting section in the following text). Since the connecting section is closer to the inside of the generator, and even part of it is located inside the generator, due to the coupling of electromagnetic induction and stray capacitance, voltage is generated on the connecting section and the connecting flange as rotating parts (for the convenience of explanation, the section due to electromagnetic induction is referred to as the connecting section in the following text). The voltage generated by the coupling effect of stray capacitance is collectively referred to as induced voltage), and the gears or bearings in the semi-direct drive gearbox are directly or indirectly in contact with the connecting section and connecting flange. The induced voltage exceeds the insulation threshold of the oil film at the gear or bearing, and local discharge will occur. The instantaneous high temperature (up to thousands of degrees Celsius) causes the metal surface to melt and oxidize, forming pitting or pits, especially the induced voltage generated by the connecting section. To this end, the technical solution adopted by the present invention is as follows: a method for solving the electrical corrosion of the semi-direct drive gearbox is proposed, and a section of the hollow tube connected to the pitch slip ring is called a connecting section, and the connecting section is grounded.

[0005] Furthermore, the connecting section is grounded via a conductive brush.

[0006] Furthermore, a mounting carrier is provided around the connecting section, and the conductive brush is arranged on the mounting carrier.

[0007] Furthermore, the other parts of the hollow tube are called tube bodies. One end of the connecting section is used to connect the pitch slip ring, and the other end of the connecting section is connected to the tube body by bolts. A gasket is provided between the connecting section and the tube body, and the gasket is made of insulating material.

[0008] Furthermore, after the tube body and the connecting section are bolted together, an insulating support sleeve is sleeved on the screw rod of the bolt, and the insulating support sleeve is located in the coupling hole for the bolt to be coupled on the tube body or / and the connecting section; an insulating gasket is sleeved on the screw rod of the bolt, and the insulating gasket is located between the nut of the bolt and the end face of the tube body, or / and the insulating gasket is located between the nut of the bolt and the end face of the connecting section.

[0009] Furthermore, the connecting flange connecting the output end of the gearbox and the rotor of the generator is made of a non-conductive material.

[0010] Furthermore, the non-conductive material is any one or more combinations of glass fiber reinforced plastics, modified nylon, modified PC or other non-metallic materials.

[0011] Furthermore, there is a connecting flange located between the output end of the gearbox and the rotor of the generator, and one end of the connecting flange is connected to the rotor of the generator, and the other end is connected to the output end of the gearbox by bolts. There is a gasket between the connecting flange and the output end of the gearbox, and the gasket is made of insulating material.

[0012] Furthermore, after the connecting flange and the output end of the gear box are bolted together, an insulating support sleeve is sleeved on the screw of the bolt, and the insulating support sleeve is located in the coupling hole for the bolt to be coupled on the connecting flange or / and the output end of the gear box; an insulating gasket is sleeved on the screw of the bolt, and the insulating gasket is located between the nut of the bolt and the end face of the connecting flange, or / and the insulating gasket is located between the nut of the bolt and the end face of the output end.

[0013] Furthermore, the bolt passes through the gasket.

[0014] Furthermore, the insulating gasket and the insulating support sleeve are integrally formed.

[0015] Furthermore, an insulating sleeve is sleeved on the screw rod, and the insulating sleeve wraps the portion of the screw rod that is not covered by the insulating support sleeve.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] The present invention focuses on solving the technical problem that "the induced voltage generated by the connecting section on the hollow tube forms a current loop in the semi-direct drive gearbox, causing electrical corrosion of the bearing and pitting corrosion of the gears". The connecting section is grounded so that the induced voltage generated by the connecting section in the changing electromagnetic field due to electromagnetic induction and stray capacitance coupling is conducted away, so that a high-voltage current loop will not be formed in the semi-direct drive gearbox, further reducing or even eliminating the electrical corrosion phenomenon in the semi-direct drive gearbox. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Figure 2 This is a schematic diagram of the assembly of the spacer, insulating gasket and insulating support sleeve;

[0021] Figure 3 This is a schematic diagram of the assembly of the conductive brush;

[0022] Markings in the figure: 1-hollow tube; 11-connecting section; 12-tube body; 2-connecting flange; 3-output end; 4-conductive brush; 5-rotor; 6-gasket; 7-bolt; 71-nut; 72-nut; 81-insulating gasket; 82-insulating support sleeve; 83-insulating sleeve; 9-pitch slip ring. DETAILED DESCRIPTION

[0023] In the description of this specification, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of this specification is usually placed when used. It is only for the convenience of describing this specification and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on this specification.

[0024] Furthermore, the use of terms such as "horizontal" and "vertical" in this specification does not necessarily imply that a component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply refers to a direction that is more horizontal than "vertical," and does not imply that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0025] In the description of this specification, it should also be noted that, unless otherwise clearly stipulated and limited, the terms "setting", "installation", "connection" and "connection" should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the internal parts of two components.

[0026] Example 1

[0027] like Figure 1-Figure 3 As shown, a method for solving the electrical corrosion of a semi-direct drive gearbox is described. A section of the hollow tube 1 connected to the pitch slip ring 9 is called a connecting section 11, and the connecting section 11 is grounded. This allows the connecting section 11 to conduct away the induced voltage generated by electromagnetic induction and stray capacitance coupling in a changing electromagnetic field, thereby preventing a current loop from being formed in the semi-direct drive gearbox, further reducing or even eliminating the electrical corrosion phenomenon in the semi-direct drive gearbox.

[0028] It should be noted that the connecting section 11 can be grounded by connecting to a grounding wire, or it can be connected to the rotor 5 of the generator through a wire. The rotor 5 of the generator is electrically connected to the grounding wire, and the grounding wire is grounded (this also exists in the prior art, and those skilled in the art are aware of this and will not be repeated here). This avoids the appearance of too many cables while meeting the grounding requirements and adapts to a compact environment.

[0029] It should be noted that the method disclosed in this embodiment does not make any changes to the structure of the hollow tube 1, but only grounds the connecting section 11. Therefore, the connection between the connecting section 11 and other parts of the hollow tube 1 and the pitch slip ring 9 remains unchanged. Its specific structure is known to those skilled in the art, and therefore, it is described in detail in this specification.

[0030] Example 2

[0031] Based on Example 1, a feasible implementation method is further proposed.

[0032] like Figure 3 As shown, a feasible implementation method is that the connecting section 11 is grounded through a conductive brush 4, which can be an electric brush or a carbon brush. The conductive brush 4 prevents the grounding wire or cable from being entangled when the hollow tube 1 rotates around its own axis, while also ensuring the stability of the induced voltage conduction.

[0033] In one feasible embodiment, a mounting carrier is provided around the connecting section 11, and the conductive brush 4 is disposed on the mounting carrier. The conductive brush 4 maintains contact with the connecting section 11 to ensure that the brush installation does not affect the normal operation of the generator and the stable conduction voltage. Alternatively, the mounting carrier may be located on the pitch slip ring 9, the generator rotor, or the generator end cap.

[0034] like Figure 1-Figure 2 As shown in FIG. 1 , a feasible embodiment is shown, in which the other parts of the hollow tube 1 are called a tube body 12, one end of the connecting section 11 is used to connect the pitch slip ring 9, and the other end of the connecting section 11 is connected to the tube body 12 by means of a bolt 7, and a gasket 6 is provided between the connecting section 11 and the tube body 12, and the gasket 6 is made of an insulating material; that is, the connecting section 11 generates an induced voltage, and due to the blocking effect generated by the gasket 6 made of a non-conductive material, the induced voltage does not form a closed electrical circuit in the semi-direct drive gearbox, and thus the metal surface will not be damaged due to the induced voltage in the semi-direct drive gearbox. The phenomenon of surface melting and oxidation occurs, further reducing or even eliminating the electric corrosion phenomenon in the semi-direct drive gearbox; based on the design of the gasket 6, on the other hand, due to the grounding wire directly connected or connected through the rotor 5 of the generator, the grounding wire itself has resistance, and the cable is long, then the resistance of the grounding wire itself is large, so the induced voltage generated by the connecting section 11 cannot be completely conducted away, it can only be reduced. By setting the gasket 6, the induced voltage on the connecting section 11 can be completely prevented from forming a closed electrical circuit in the semi-direct drive gearbox, even if there is a residual induced voltage.

[0035] Furthermore, after the tube body 12 and the connecting section 11 are bolted together, an insulating support sleeve 82 is sleeved on the screw of the bolt 7, and the insulating support sleeve 82 is located in the engagement hole for the bolt 7 on the tube body 12 or / and the connecting section 11; an insulating gasket 81 is sleeved on the screw of the bolt 7, and the insulating gasket 81 is located between the nut 71 of the bolt 7 and the end face of the tube body 12, or / and the insulating gasket 81 is located between the nut 71 of the bolt 7 and the end face of the connecting section 11; the insulating gasket 81 and the insulating support sleeve 82 are both made of insulating materials, and the screw is supported by the insulating support sleeve 82, so that the screw and the tube body 12 or / and A gap is formed between the inner wall of the engagement hole on the connecting section 11, thereby blocking the contact between the screw and the tube body 12 and / or the connecting section 11. At the same time, the insulating gasket 81 can also block the contact between the nut 71 and the tube body 12 and / or the end face of the connecting section 11. In summary, through the cooperation of the insulating gasket 81 and the insulating support sleeve 82, the contact between the screw and the nut 71 in the bolt 7 and the tube body 12 can be effectively isolated, thereby achieving the purpose of isolating the electrical connection, and effectively avoiding the induced voltage on the connecting section 11 from being electrically connected to the tube body 12 through the bolt 7. On the other hand, the design of the insulating gasket 81 and the insulating support sleeve 82 is also convenient for installation and disassembly.

[0036] Example 3

[0037] In Example -, it is mainly proposed to solve the impact of the induced voltage generated on the hollow tube 1 on the semi-direct drive gearbox. As described in the invention content in this specification, the connecting flange 2 will also generate induced voltage. Therefore, based on Example -, a specific implementation method that can be implemented is further proposed.

[0038] In the first embodiment, the connecting flange 2 connecting the output end 3 of the gearbox and the rotor 5 of the generator is made of non-conductive material. By replacing the metal material with the non-conductive material, the connecting flange 2 will not generate an induced voltage in a changing electromagnetic field, thereby not forming a high-voltage current loop in the semi-direct drive gearbox, further reducing or even eliminating the electrical corrosion phenomenon in the semi-direct drive gearbox.

[0039] For the first embodiment, the above-mentioned non-conductive material is any one of fiberglass, modified nylon, and modified PC. Although fiberglass, modified nylon, and modified PC are commonly used non-conductive materials on the market, they are not currently used in the manufacture of the connecting flange 2. This embodiment proposes to use this material to manufacture the connecting flange 2, which mainly can meet the non-conductive requirements on the one hand and meet the strength requirements after replacement on the other hand.

[0040] It should be noted that, under the premise of meeting the non-conductive requirements and strength requirements, the non-conductive material is not limited to any one of the above-mentioned fiberglass, modified nylon, and modified PC, but can also be any one or more combinations of fiberglass, modified nylon, modified PC or other non-metallic materials.

[0041] like Figure 2 As shown, in the second embodiment, there is a connecting flange 2 located between the output end 3 of the gearbox and the rotor 5 of the generator, and one end of the connecting flange 2 is connected to the rotor 5 of the generator, and the other end is connected to the output end 3 of the gearbox by bolts 7. There is a gasket 6 between the connecting flange 2 and the output end 3 of the gearbox, and the gasket 6 is made of insulating material; that is, the connecting flange 2 generates an induced voltage, and due to the blocking effect generated by the gasket 6 made of insulating material, the induced voltage will not form a closed electrical circuit in the semi-direct drive gearbox, and thus the metal surface will not melt or oxidize due to the induced voltage in the semi-direct drive gearbox, thereby further reducing or even eliminating the electrical corrosion phenomenon in the semi-direct drive gearbox.

[0042] It should be noted that, for the second embodiment, compared with the first embodiment, the connecting flange 2 is made of metal material, so an induced voltage will also be generated, and the connecting flange 2 is connected to the rotor 5 of the generator, and the rotor 5 of the generator is electrically connected to a grounding wire, and the grounding wire is grounded (this also exists in the prior art, and those skilled in the art are aware of this and will not be repeated here). Therefore, the induced voltage generated by the connecting flange 2 will pass through the rotor 5 of the generator and the grounding wire and then be grounded, so the induced voltage generated on the connecting flange 2 will not accumulate excessively, and there will be no situation where the voltage is too high to break through the gasket 6, that is, the second embodiment can work for a long time.

[0043] Further, if Figure 2 As shown, for the second embodiment, after the connecting flange 2 and the output end 3 of the gear box are bolted together, there is an insulating support sleeve 82 sleeved on the screw of the bolt 7, and the insulating support sleeve 82 is located in the coupling hole for the bolt 7 on the connecting flange 2 or / and the output end 3 of the gear box; there is an insulating gasket 81 sleeved on the screw of the bolt 7, and the insulating gasket 81 is located between the nut 71 of the bolt 7 and the end face of the connecting flange 2, or / and the insulating gasket 81 is located between the nut 71 of the bolt 7 and the end face of the output end 3; the effect and implementation principle achieved are similar to those in the embodiment in which the insulating support sleeve 82 and the insulating gasket 81 are present, and will not be described in detail here.

[0044] Example 4

[0045] Based on the solutions disclosed in Examples 2-3, a feasible implementation method is further proposed.

[0046] In a feasible implementation manner, the screw rod of the bolt 7 passes through the gasket 6 so that the gasket 6 can be supported by the screw rod, thereby improving the position stability of the gasket 6.

[0047] A feasible implementation method is that the outer diameter of the insulating support sleeve 82 matches the inner diameter of the handle hole, and the inner diameter of the insulating support sleeve 82 matches the diameter of the screw; this method can make the axis of the screw and the axis of the handle hole collinear after the insulating support sleeve 82 is made into a screw, on the one hand, improving the stability of the structure and avoiding position fluctuations; on the other hand, it avoids the situation where the voltage breaks through the air due to a position being too close at a certain point, causing the isolation electrical connection to fail.

[0048] Furthermore, the insulating gasket 81 and the insulating support sleeve 82 are integrally formed, that is, a sleeve-like structure with a T-shaped cross-section is formed. This structure can use the end face of the insulating gasket 81 as a positioning surface, which can effectively improve the dimensional accuracy for the coaxial installation of the insulating support sleeve 82.

[0049] A feasible implementation method, as described above, although there is a gap between the screw and the inner wall of the handle hole under the action of the insulating support sleeve 82, it is also possible that the air in the gap is broken down due to excessive voltage. In order to prevent this situation from happening, the screw and nut 71 in the isolation bolt 7 and the output end 3 of the gear box are ensured; or / and the screw and nut 71 in the isolation bolt 7 and the tube body 12 are ensured to avoid the induced voltage generated at the connecting flange 2 from being connected to the output end 3 of the gear box, or / and avoid the induced voltage generated at the connecting section 11 from being connected to the tube body 12; further design is that an insulating sleeve 83 is also provided on the screw, and the insulating sleeve 83 wraps the part of the screw that is not covered by the insulating support sleeve 82.

[0050] Furthermore, the insulating support sleeve 82 can be integrally formed with the insulating sleeve 83 .

[0051] Example 5

[0052] A hollow tube 1 comprises a tube body 12 and a connecting section 11. One end of the connecting section 11 is used to connect to a pitch slip ring 9, and the other end of the connecting section 11 is connected to the tube body 12. A grounding wire is connected to the connecting section 11, and the grounding wire is grounded.

[0053] In a feasible implementation manner, the hollow tube 1 can be used in the methods described in Examples 1-4.

[0054] In a feasible implementation manner, a conductive brush 4 is installed on the pitch slip ring 9 , the conductive brush 4 is in contact with the connecting section 11 , and the grounding wire is connected to the conductive brush 4 .

[0055] In a feasible implementation manner, a gasket 6 made of insulating material is provided between the pipe body 12 and the connecting section 11 .

[0056] In a feasible implementation manner, the pipe body 12 and the connecting section 11 are fastened together by a bolt 7 , and the screw in the bolt 7 passes through the gasket 6 .

[0057] A feasible implementation method is that after the tube body 12 and the connecting section 11 are bolted together, there is an insulating support sleeve 82 that is sleeved on the screw rod of the bolt 7, and the insulating support sleeve 82 is located in the coupling hole for the bolt 7 on the tube body 12 and / or the connecting section 11; there is an insulating gasket 81 that is sleeved on the screw rod of the bolt 7, and the insulating gasket 81 is located between the nut 71 of the bolt 7 and the end face of the tube body 12, or / and the insulating gasket 81 is located between the nut 71 of the bolt 7 and the end face of the connecting section 11.

[0058] Furthermore, an insulating sleeve 83 is sleeved on the screw, and the insulating sleeve 83 wraps the portion of the screw that is not covered by the insulating support sleeve 82.

[0059] It should be noted that the structure of the tube body 12 and the connecting section 11 of the hollow tube 1 is known to those skilled in the art. This specification focuses on the grounding of the connecting section 11 and the installation of the insulating gasket 81. For this reason, the specific structure of the hollow tube 1 will not be described in detail in this specification.

[0060] Example 6

[0061] A semi-direct drive gearbox has the hollow tube 1 described in Example 5.

[0062] 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.

[0063] Example 7

[0064] A wind turbine generator set having the semi-direct drive gearbox described in Example 6.

[0065] 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.

[0066] The present invention is not limited to the aforementioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A method for solving the electrical corrosion of a semi-direct drive gearbox, characterized by: A section of the hollow tube (1) connected to the pitch slip ring (9) is called a connecting section (11), and the connecting section (11) is grounded.

2. The method according to claim 1, wherein: The connecting section (11) is grounded via a conductive brush (4).

3. The method according to claim 2, wherein: A mounting carrier is provided around the connecting section (11), and the conductive brush (4) is arranged on the mounting carrier.

4. The method according to claim 1, wherein: The other parts of the hollow tube (1) are called the tube body (12). One end of the connecting section (11) is used to connect the pitch slip ring (9). The other end of the connecting section (11) is connected to the tube body (12) by bolts (7). A gasket (6) is provided between the connecting section (11) and the tube body (12), and the gasket (6) is made of insulating material.

5. The method according to claim 4, characterized in that: After the tube body (12) and the connecting section (11) are engaged with the bolt (7), an insulating support sleeve (82) is sleeved on the screw of the bolt (7), and the insulating support sleeve (82) is located in an engagement hole on the tube body (12) or / and the connecting section (11) for the bolt (7) to engage; an insulating gasket (81) is sleeved on the screw of the bolt (7), and the insulating gasket (81) is located between the nut (71) of the bolt (7) and the end face of the tube body (12), or / and the insulating gasket (81) is located between the nut (71) of the bolt (7) and the end face of the connecting section (11).

6. The method according to claim 1, wherein: The connecting flange (2) for connecting the output end (3) of the gearbox and the rotor (5) of the generator is made of a non-conductive material.

7. The method according to claim 6, characterized in that: The non-conductive material is any one or more combinations of glass fiber reinforced plastics, modified nylon, modified PC or other non-metallic materials.

8. The method according to claim 1, wherein: A connecting flange (2) is located between the output end (3) of the gearbox and the rotor (5) of the generator, and one end of the connecting flange (2) is connected to the rotor (5) of the generator, and the other end is connected to the output end (3) of the gearbox by bolts (7). A gasket (6) is present between the connecting flange (2) and the output end (3) of the gearbox, and the gasket (6) is made of insulating material.

9. The method according to claim 8, characterized in that: After the connecting flange (2) and the output end (3) of the gear box are bolted together, an insulating support sleeve (82) is sleeved on the screw of the bolt (7), and the insulating support sleeve (82) is located in a fitting hole on the connecting flange (2) or / and the output end (3) of the gear box for the bolt (7) to fit together; an insulating gasket (81) is sleeved on the screw of the bolt (7), and the insulating gasket (81) is located between the nut (71) of the bolt (7) and the end face of the connecting flange (2), or / and the insulating gasket (81) is located between the nut (71) of the bolt (7) and the end face of the output end (3).

10. The method according to claim 5 or 9, characterized in that: The bolt (7) passes through the washer (6).

11. The method according to claim 5 or 9, characterized in that: The insulating gasket (81) and the insulating support sleeve (82) are integrally formed.

12. The method according to claim 5 or 9, characterized in that: The screw rod is also covered with an insulating sleeve (83), which wraps the portion of the screw rod that is not covered by the insulating support sleeve (82).

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