Shaft current suppression structure for hollow tube of wind turbine generator set gear box

Abstract

The utility model provides a kind of wind generating set gear box hollow tube's shaft current suppression structure, hollow tube includes generator side section and gear box side section, the structure includes: first insulation component, the first insulation component is connected in series in the conduction path of gear box hollow tube along axial direction, and at least the electrical path of the induction shaft voltage of the generator side section is conducted to the gear box side section via the hollow tube wall surface is blocked;Flow guide component, the flow guide component is electrically connected with the generator side section and is grounded, for bypassing the shaft current on the generator side section to ground system.Through the above structure, first insulation component is connected in series in the conduction path of hollow tube and cooperates flow guide ground, from the source, cut off the channel of the induction shaft voltage of generator side to the conduction of gear box side, so that main bearing and gear box bearing are no longer the conduction path of shaft current, avoid the shaft current from hollow tube damage the bearing of main shaft, the bearing and gear of gear box.

Description

Technical Field

[0001] This utility model relates to the field of wind turbine generators, and in particular to a shaft current suppression structure for a hollow tube in a wind turbine generator gearbox. Background Technology

[0002] As the single-unit capacity and rotor diameter of wind turbine generators continue to increase, the requirements for bearing reliability in their transmission chains are becoming increasingly stringent. During operation, due to electromagnetic induction and the common-mode voltage of the converter, shaft voltage is generated inside the generator on the rotor and its connected hollow shaft. When the shaft voltage exceeds the bearing lubricating oil film threshold, shaft current will form and be released along the nearest metal path, leading to electrolytic pits, melting pits, and microcracks on the bearing raceway and rolling element surfaces, as well as electrolytic corrosion of the gearbox gears. This, in turn, causes increased vibration, accelerated temperature rise, and premature spalling, significantly shortening bearing life and increasing unit downtime maintenance costs.

[0003] For compact semi-direct drive turbines, the gearbox output shaft and generator rotor shaft share a single through-type hollow tube. This hollow tube connects to a slip ring at its rear end and passes through the entire gearbox. During operation, the outer wall of the hollow tube becomes a continuous conductive channel, allowing shaft current to be directly transmitted to the main bearing and all stages of the gearbox bearings and gears, resulting in multi-point electrical erosion. Currently, there is no dedicated blocking and shunting structure for the complete conduction chain of "hollow tube-main bearing-gearbox bearings & gears." Existing solutions generally suffer from high cost, limited installation space, or incomplete blocking of the transmission path, making it difficult to meet the requirements of semi-direct drive turbines for high power density, high reliability, and low maintenance.

[0004] Therefore, there is an urgent need for a shaft current suppression scheme that is simple in structure, easy to assemble, and has both blocking and bypassing functions, in order to solve the technical problem of shaft current corrosion in the hollow tube of the transmission chain of compact wind turbine generator sets. Utility Model Content

[0005] The technical problem to be solved by this utility model is that the shaft current suppression methods of the hollow tube of the wind turbine gearbox are costly, have limited installation space, or do not completely block the path, making it difficult to meet the requirements of semi-direct drive units for high power density, high reliability, and low maintenance. The present invention provides a shaft current suppression structure for the hollow tube of the wind turbine gearbox.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] A shaft current suppression structure for a hollow tube in a wind turbine generator gearbox, the hollow tube comprising a generator-side section and a gearbox-side section, the structure comprising:

[0008] A first insulating component is connected in series along the axial direction in the conductive path of the hollow tube of the gearbox, and at least blocks the electrical path of the induced shaft voltage of the generator side section being conducted through the wall of the hollow tube toward the gearbox side section.

[0009] A current-guiding assembly, which is electrically connected to and grounded to the generator side section, is used to bypass the shaft current on the generator side section to the grounding system.

[0010] In this scheme, the above structure is adopted, and a first insulating component is inserted in series in the conductive path of the hollow tube and grounded in conjunction with current conduction. This cuts off the channel for the induced shaft voltage on the generator side to be conducted to the gearbox side from the source, so that the main bearing and the gearbox bearing no longer become the path for shaft current, thus avoiding damage to the bearings of the main shaft, the bearings of the gearbox, and the gears by the shaft current from the hollow tube.

[0011] Preferably, the first insulating component is embedded between the generator side section and the gearbox, and both ends of the first insulating component are axially connected to and fixed to the generator side section and the gearbox side section, respectively.

[0012] In this solution, the above structure is used to directly embed the first insulating component between the generator side section and the gearbox side section, so that the insulating component forms part of the hollow tube and insulates the hollow tube itself, preventing the shaft current on the hollow tube from flowing into the main bearing. No additional insulating structure is required, thus improving space utilization.

[0013] Preferably, the first insulating component is provided with a first connection structure at both ends facing the generator side section and the gearbox side section;

[0014] The generator side section and the gearbox side section are provided with a second connection structure at their ends facing the first insulating component;

[0015] The first connecting structure and the second connecting structure are convex and concave parts with adapted shapes;

[0016] The first insulating component is connected to the generator side section and the gearbox side section by tenon and mortise joints to restrict the relative rotation of the first insulating component and the generator side section or the gearbox side section in the axial direction.

[0017] In this solution, the above-mentioned structure is adopted. By utilizing the circumferential limiting effect of the first / second connection structure, the torque load is reliably transferred from the metal tube to the insulating component, increasing the connection strength between the hollow tube and the first insulating component. The convex-concave shape adaptation is adopted to form a tenon and mortise structure, which increases the connection strength.

[0018] Preferably, the first connecting structure and the second connecting structure are respectively disposed on the outer side of the end face of the first insulating component and the generator side section or the gearbox side section, forming an open groove and a protrusion;

[0019] or,

[0020] The first connection structure and the second connection structure are respectively disposed on the inner side of the end face of the first insulating component and the generator side section or the gearbox side section, forming a closed keyway and an inner convex key.

[0021] In this solution, the above-mentioned structure is adopted, and the first connecting structure and the second connecting structure are arranged in two forms: "outer ring open groove-protrusion" or "internal closed keyway-inner convex key".

[0022] Open outer ring: In this method, the groove is formed on the surface of the pipe fitting, and both the outer peripheral surface and the end face of the pipe fitting are open, making the groove visible. This simplifies processing and alignment, and makes assembly intuitive.

[0023] Internally enclosed: The mating surfaces are hidden inside the end face, and there are no openings on the outer circumference, resulting in a simple appearance. At the same time, due to the shortened lever arm, more uniform torque transmission and higher tensile strength can be obtained under the same size.

[0024] Preferably, a first connecting structure is provided at both ends of the first insulating component, and the first connecting structures at both ends are staggered in the circumferential direction of the first insulating component so that the projections of the first connecting structures at both ends on the radial plane of the first insulating component do not at least partially overlap.

[0025] In this solution, the above structure is adopted. The radial plane refers to the plane that is perpendicular to the axis of the circular tube and passes through the center of the circle, i.e., the cross-section of the first insulating component. The first connecting structures at both ends of the first insulating component are staggered to make the shear force on each part of the insulating component uniform and increase its service life.

[0026] Preferably, the first insulating component is an insulating long tube, at least a portion of which extends to connect with the slip ring, such that the entire hollow tube on the generator side is made of insulating material.

[0027] In this scheme, the above structure is adopted, and the insulated long tube extends directly to the slip ring, turning the entire "generator-side hollow tube" into a high-resistivity body, fundamentally eliminating the induced voltage source.

[0028] Preferably, the first insulating component consists of an insulating cylinder and an adhesive layer. The insulating cylinder is axially sleeved with the adjacent generator side section and / or the gearbox side section through a tenon and mortise fit, and forms torque transmission and electrical isolation through adhesive curing.

[0029] In this solution, the above structure is adopted, and the insulating cylinder and the adjacent metal section are connected by tenon and mortise joints and glued together, which simultaneously achieves the dual functions of "torque transmission" and "electrical isolation", eliminating the need for additional flanges and bolts and simplifying the structure.

[0030] Preferably, it also includes:

[0031] The second insulation component is disposed between the hollow tube on the side of the gearbox and the rear end cover of the main shaft, and is used to block the conduction path of shaft current from the hollow tube to the main bearing.

[0032] In this solution, the above-mentioned structure is adopted, and a second insulating component is added between the hollow tube on the side of the gearbox and the rear end cover of the main shaft. On the basis that the first insulating component has blocked the main conduction path, the residual path leading to the main bearing through the flange-bolt-end cover is further cut off, forming a "segmented isolation" pattern. This avoids the main bearing from becoming the outlet for shaft current, significantly reduces the risk of electro-erosion, and improves the reliability of the transmission chain.

[0033] Preferably, the second insulating assembly includes an insulating bolt, an insulating gasket, and insulating paper. The insulating bolt secures the flange of the hollow tube to the rear end cover of the main shaft, and the insulating gasket and the insulating paper are disposed on both sides of the flange.

[0034] In this solution, the above-mentioned structure is adopted. By using the combination of insulating bolts, insulating gaskets and insulating paper, a continuous insulating barrier can be established on both sides of the flange simply by replacing the existing fasteners. There is no need to change the original shape and size of the end cap or hollow tube, so as to achieve low-cost and quick assembly of secondary protection, while maintaining the flange connection rigidity and ensuring that torque transmission is not affected.

[0035] Preferably, the current guiding assembly includes a retaining ring, brush filaments, and a flexible copper braid. The retaining ring is fastened to the outer periphery of the generator side section, and the brush filaments are in conductive contact with the retaining ring and connected to the unit grounding grid via the copper braid to achieve low-impedance grounding of the shaft current.

[0036] In this solution, the above-mentioned structure is adopted. The generator side hollow tube is directly connected in parallel with the unit grounding grid through the current guiding component composed of a retaining ring, brush wire, and flexible copper braid, forming a low-impedance bypass. This allows the shaft current to be discharged preferentially through the brush wire and copper braid, reducing the current share flowing through the bearing, thereby alleviating bearing raceway electro-corrosion and extending the maintenance cycle and service life.

[0037] The positive and progressive effects of this utility model are as follows: Through the shaft current suppression structure of the hollow tube of the wind turbine generator gearbox in this solution, a first insulating component is inserted in series in the conductive path of the hollow tube and cooperated with current conduction grounding to cut off the channel for the induced shaft voltage on the generator side to be conducted to the gearbox side from the source, so that the main bearing and the gearbox bearing no longer become the path of shaft current, and avoid the shaft current from the hollow tube from damaging the bearings of the main shaft, the bearings of the gearbox and the gears. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the shaft current suppression structure of the hollow tube of the wind turbine generator gearbox in Embodiment 1 of this utility model.

[0039] Figure 2 for Figure 1 A magnified view of a portion of the image.

[0040] Figure 3 for Figure 2 Cross-sectional view of the gearbox side section / generator side section on the X-plane.

[0041] Figure 4 for Figure 2 Cross-sectional view of the first insulating component on the X-plane.

[0042] Figure 5 This is a schematic diagram of the structure for suppressing shaft current in the hollow tube of a wind turbine gearbox.

[0043] Figure 6 for Figure 5 Cross-sectional view of the first insulating component on the X-plane.

[0044] Figure 7 for Figure 5 Cross-sectional view of the gearbox side section / generator side section on the Y-plane.

[0045] Figure 8 This is a schematic diagram of the shaft current suppression structure of the hollow tube gearbox of the wind turbine generator set according to Embodiment 2 of this utility model.

[0046] Explanation of reference numerals in the attached figures:

[0047] Gearbox side section A

[0048] Generator side section B

[0049] First insulation component 10

[0050] Main bearing 1 / 3

[0051] High-speed bearing 2

[0052] Gearbox 4

[0053] Unit slip ring 9

[0054] First connection structure 21

[0055] Second connection structure 11 Detailed Implementation

[0056] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0057] Example 1

[0058] Figures 1 to 3 A specific implementation of a shaft current suppression structure for a hollow tube gearbox in a semi-direct drive wind turbine generator set is presented.

[0059] like Figure 1 As shown, the hollow tube includes a generator side section B and a gearbox side section A along the axial direction, and the two sections are connected in series by a first insulating component 10; a flow guiding component is provided on the outer periphery of the generator side section B; a second insulating component (not shown in the figure) is provided between the flange of the gearbox side section A and the rear end cover of the main bearings 1 and 3.

[0060] like Figure 1 , 2 As shown in Figures 3 and 4, the first insulating component 10 is an integral cylindrical insulator, axially inserted between the generator-side section B and the gearbox-side section A, preventing the two metal tubes from directly conducting electricity. During operation, the shaft voltage of the generator-side hollow tube is interrupted by the first insulating component 10, preventing it from propagating along the tube wall to the gearbox side, thereby reducing the shaft current of the main bearing 1 / 3 and the high-speed bearing 2. The current-conducting component makes conductive contact with the generator-side section B and conducts residual charge to the housing ground, forming a dual protection of "blocking + bypassing". This arrangement does not require changing the inner diameter of the original hollow tube, nor does it affect the torque transmission path.

[0061] Embedded position such as Figures 2 to 4 As shown, the two end faces of the first insulating component 10 are axially aligned with the end faces of the generator-side section B and the gearbox-side section A, respectively, and are fixed by bonding or slight interference fit. Both bonding and slight interference fit can also be used simultaneously to achieve a better connection effect, making the insulating component an integral part of the hollow tube itself. Compared to adding an insulating flange to the outside of the tube, this embedded solution does not occupy additional axial space and does not require increasing the unit length, exhibiting good compatibility with existing semi-direct drive models.

[0062] In this embodiment, the first insulating component 10 is connected to the hollow tube by a tenon and mortise joint to improve torsional strength. Specifically, the first insulating component 10 has a first connecting structure 21 (protrusion or recess) at both ends, and a second connecting structure 11 (recess or protrusion) at the corresponding ends of the generator side section B and the gearbox side section A. During assembly, the first connecting structure 21 and the second connecting structure 11 fit together to form a circumferential lock, preventing relative rotation between the first insulating component 10 and the metal tube section. The mating surfaces of the protrusion and the recess can be rectangular, trapezoidal, or involute, as long as they can achieve the "insertion-anti-rotation" function.

[0063] Specifically, in this embodiment, the following is adopted: Figures 2 to 4 An open design is shown: the groove is located on the outer ring of the end face and extends to the outer peripheral surface, the assembly marks are visible, the machining and alignment are intuitive, and it is convenient for on-site maintenance.

[0064] In another embodiment, using Figures 5 to 7 The closed design is shown: the groove is completely hidden inside the end face, the outer circumference has no opening, the appearance is continuous, and the lever arm can be reduced and the pull-out resistance can be improved because the mating position is close to the center.

[0065] Both forms can be used individually or mixed at both ends of the same first insulating component 10, and both can achieve the purpose of stopping rotation.

[0066] Furthermore, after the insulating cylinder 22 of the first insulating component 10 is sleeved with the metal pipe section, epoxy or acrylic structural adhesive is injected into the mating surface. After curing at room temperature, it can transmit the rated torque. The adhesive layer can fill in processing errors and provide a second electrical barrier to ensure long-term operation without failure.

[0067] Furthermore, in this embodiment, the insulating cylinder 22 can be made of fiber-reinforced resin-based composite material or engineering ceramics. The former is lightweight and easy to process; the latter has better temperature resistance and tracking resistance. Users can choose according to environmental conditions, and both can meet the insulation and strength requirements.

[0068] like Figure 1 As shown, the second insulation component (not shown in the figure) is located between the gearbox side section A flange and the main shaft rear end cover, and includes insulating bolts, insulating gaskets, and insulating paper. During assembly, simply replace the original metal bolts with insulating bolts and install insulating gaskets and insulating paper on both sides of the flange. This maintains the original connection rigidity while blocking the path of shaft current flowing through the flange-bolt-end cover to the main bearing 1 / 3, achieving the function of a "rear gate". No additional processing is required, on-site replacement time is short and cost is low, and the creepage distance can be significantly increased, providing redundant protection for the main bearing 1 / 3.

[0069] The current-guiding assembly is a grounding device fitted onto a hollow tube. Connected to a slip ring, it contains components such as a retaining ring, brush filaments, wires, or copper braids (not shown in the figure). Connecting the generator side section and the rotor support, it directly grounds the hollow tube inside the generator. This directs shaft current to the rotor brake disc, rotor support, or gearbox components with good conductivity to the grounding system, reducing damage to the bearings from shaft current. Specifically, the retaining ring clamps tightly to the outer circumference of the generator side section, the brush filaments make conductive contact with the retaining ring under spring pressure, and the copper braids conduct the current to the casing grounding grid. The entire assembly can rotate with the shaft. During maintenance, simply loosening the retaining ring allows for brush filament replacement without disassembling the coupling or brake disc, simplifying operation.

[0070] Example 2

[0071] The shaft current suppression structure of the hollow tube of the wind turbine gearbox in this embodiment is roughly the same as that in Embodiment 1, except for the positions of the first connecting structure 21 and the second connecting structure 11.

[0072] In this embodiment, as Figure 8 As shown, when both ends of the first insulating component 10 are made of protrusions or keyways, the protrusions (or keyways) at both ends can be staggered in the circumferential direction so that their projections on the plane where the end face of the first insulating component 10 is located (the two end faces of the first insulating component 10 are parallel planes) do not coincide. This makes the stress on each part of the insulating component more uniform, reduces local shear stress, and extends the life of the insulating component.

[0073] Specifically, the first connecting structures 21 at both ends of the first insulating component 10 are staggered in the circumferential direction of the first insulating component 10 so that the projections of the first connecting structures 21 at both ends onto the radial plane of the first insulating component 10 do not at least partially coincide. The radial plane refers to a plane perpendicular to the axis of the first insulating component 10 and passing through the center of the circle, that is, the cross-section of the first insulating component.

[0074] Furthermore, the gearbox side section A and generator side section B of the hollow tube are provided with dovetail tenons, i.e., the outer opening is narrow and the bottom opening is wide. Gearbox side section A and generator side section B are respectively connected to connecting sleeves made of insulating material (i.e., the first insulating component 10). The first insulating component 10 is provided with tenons that mate with the dovetail tenons. The top of the tenon is wide and the root is narrow. The tenons on both sides of the connecting sleeve are not in the same plane. During assembly, the tenons and tenons are inserted into the tenons in the radial direction of the hollow tube. The structure can be strengthened by using structural adhesive bonding or by adding a ring made of insulating material to the outside of the connecting sleeve.

[0075] Example 3

[0076] The shaft current suppression structure of the hollow tube of the wind turbine gearbox in this embodiment is roughly the same as that in Embodiment 1, except for the arrangement of the first insulation component 10.

[0077] In this embodiment, the first insulating component 10 is directly extended into an insulating long tube, with its right end extending to the connecting flange of the unit slip ring 09, so that the entire hollow tube on the generator side is made of insulating material. This solution eliminates induced voltage at the source, further reducing the probability of shaft current generation, and is suitable for new machine design or major renovation.

Claims

1. A shaft current suppression structure for a hollow tube in a wind turbine generator gearbox, the hollow tube comprising a generator-side section and a gearbox-side section, characterized in that, The structure includes: A first insulating component is connected in series along the axial direction in the conductive path of the hollow tube of the gearbox, and at least blocks the electrical path of the induced shaft voltage of the generator side section being conducted through the wall of the hollow tube to the gearbox side section. A current-guiding assembly, which is electrically connected to and grounded to the generator side section, is used to bypass the shaft current on the generator side section to the grounding system.

2. The shaft current suppression structure of the hollow tube of the wind turbine generator gearbox as described in claim 1, characterized in that, The first insulating component is embedded between the generator side section and the gearbox, and its two ends are axially connected and fixed to the generator side section and the gearbox side section, respectively.

3. The shaft current suppression structure of the hollow tube of the wind turbine generator gearbox as described in claim 2, characterized in that, The first insulating component has a first connection structure at both ends facing the generator side section and the gearbox side section; The generator side section and the gearbox side section are provided with a second connection structure at their ends facing the first insulating component; The first connecting structure and the second connecting structure are convex and concave parts with adapted shapes; The first insulating component is connected to the generator side section and the gearbox side section by tenon and mortise joints to restrict the relative rotation of the first insulating component and the generator side section or the gearbox side section in the axial direction.

4. The shaft current suppression structure of the hollow tube of the wind turbine generator gearbox as described in claim 3, characterized in that, The first connection structure and the second connection structure are respectively disposed on the outer side of the end face of the first insulating component and the generator side section or the gearbox side section, forming an open groove and a protrusion; or, The first connection structure and the second connection structure are respectively disposed on the inner side of the end face of the first insulating component and the generator side section or the gearbox side section, forming a closed keyway and an inner convex key.

5. The wind turbine generator set gear box hollow tube shaft current suppression structure according to claim 3, characterized in that, The first insulating component has a first connecting structure at both ends, and the first connecting structures at both ends are staggered in the circumferential direction of the first insulating component so that the projections of the first connecting structures at both ends on the radial plane of the first insulating component do not overlap at least partially.

6. The shaft current suppression structure of the hollow tube of the wind turbine generator gearbox as described in claim 1, characterized in that, The first insulating component is an insulating long tube, at least a portion of which extends to connect with a slip ring, so that the entire hollow tube on the generator side is made of insulating material.

7. The shaft current suppression structure of the hollow tube of the wind turbine generator gearbox as described in any one of claims 1 to 6, characterized in that, The first insulating component consists of an insulating cylinder and an adhesive layer. The insulating cylinder is axially sleeved with the adjacent generator side section and / or the gearbox side section through tenon and mortise joints, and forms torque transmission and electrical isolation through adhesive curing.

8. The shaft current suppression structure of the hollow tube of the wind turbine generator gearbox as described in claim 1, characterized in that, Also includes: The second insulation component is disposed between the hollow tube on the side of the gearbox and the rear end cover of the main shaft, and is used to block the conduction path of shaft current from the hollow tube to the main bearing.

9. The shaft current suppression structure for the hollow tube of the wind turbine generator gearbox as described in claim 8, characterized in that, The second insulating assembly includes an insulating bolt, an insulating gasket, and insulating paper. The insulating bolt secures the flange of the hollow tube to the rear end cover of the main shaft, and the insulating gasket and the insulating paper are disposed on both sides of the flange.

10. The shaft current suppression structure of the hollow tube of the wind turbine generator gearbox as described in claim 1, characterized in that, The current guiding assembly includes a retaining ring, brush filaments, and a flexible copper braid. The retaining ring is fastened to the outer periphery of the generator side section, and the brush filaments are in conductive contact with the retaining ring and connected to the unit grounding grid through the copper braid to achieve low-impedance grounding of the shaft current.

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