An insulating end cover structure suitable for offshore wind turbines

Abstract

The present invention discloses an insulating end cover structure suitable for offshore wind turbines, including an annular insulating end cover, a bearing chamber is installed in the annular insulating end cover, an insulating layer and a sealing mechanism are provided at the connection between the two, a bearing is provided in the bearing chamber, and the bearing is movably installed on the circumferential surface of the rotor; wherein, a stator is connected to the outer end surface of the annular insulating end cover, and a grounding brush in contact with the rotor is installed on the stator for conducting the shaft current between the stator and the rotor; after the annular insulating end cover and the bearing chamber are assembled, a vacuum pressure varnishing treatment is first performed to fill the gap between the two, and at the same time, the entire insulating layer is covered and wrapped to form a dense protective layer to prevent moisture from entering, and then a water immersion test is performed, and after the insulation resistance meets the standard, fine processing is performed to ensure the moisture resistance of the structure. The insulating end cover structure of the present invention adopts multiple measures to prevent moisture from entering the insulating layer, significantly improving the reliability of the insulating end cover, and is particularly suitable for complex and humid environments at sea.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore wind turbine generator devices, and in particular relates to an insulating end cover structure suitable for offshore wind turbine generators. Background Art

[0002] At present, compared with the development of onshore wind farms, offshore wind power has the advantages of not occupying land, more stable wind resources, higher wind speed, less environmental impact on human production and life, and significantly better efficiency than onshore wind farms. Therefore, it has become an important direction for the development of global wind power in the future. my country has a long coastline and a vast area of ​​available sea areas, rich wind energy resources, and the offshore wind energy value is about three times that of onshore wind energy. The development of offshore and offshore wind turbines has broad application prospects.

[0003] As we all know, due to the special offshore environment, the generator is required to have the ability to adapt to high salt spray and high humidity environments. In addition, due to the difficulty in maintenance, the maintenance cost of offshore wind turbines accounts for about 25% of the cost of electricity, and higher requirements are placed on reliability and maintainability. Therefore, in order to improve the reliability of wind turbines, measures are usually taken to suppress shaft current to avoid electrical corrosion damage to bearings. The effective measure to suppress shaft current is usually to use insulating end covers. However, if the insulating end cover structure on land is directly used in offshore wind turbines, it is difficult to adapt to the high humidity environment conditions at sea.

[0004] In order to reduce the maintenance workload, offshore wind turbines usually use oil lubrication structure to avoid frequent grease replenishment. At the same time, the lubrication effect is good and can ensure a low bearing temperature. When oil lubrication is used, the lubricating oil pipe is usually made of metal to meet the 25-year use requirement, which will short-circuit the insulating layer of the insulating end cover. Usually, in order to reduce costs, the generator and the gearbox share a lubrication system. After the lubricating oil has been running for a long time, iron filings and powder from the wear of gears and other parts will enter the lubricating oil, causing bearing damage. If the contaminated lubricating oil enters the insulating layer of the insulating end cover, it will cause the insulation layer to fail to conduct. However, the existing technology does not have an effective means to solve this problem.

[0005] In view of this, the inventor proposes an insulating end cover structure suitable for an offshore wind turbine to overcome the defects of the prior art. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an insulating end cover structure suitable for offshore wind turbines. The end cover structure of the present invention solves the problems of wind turbines in high humidity environments at sea and insulation layer failure caused by oil lubrication structure.

[0007] The purpose of the present invention is to be solved by the following technical solutions:

[0008] An insulating end cover structure suitable for an offshore wind turbine generator comprises an annular insulating end cover, a bearing chamber is installed at the inner ring and inner end surface of the annular insulating end cover, a sealing mechanism is provided at the connection between the annular insulating end cover and the bearing chamber, a bearing is provided in the bearing chamber, and the bearing is movably installed on the circumferential surface of a rotor;

[0009] Wherein, the outer end surface of the annular insulating end cover is connected to a stator, and a grounding brush is installed on the stator, and the end of the grounding brush contacts the circumferential surface of the rotor to conduct the shaft current between the stator and the rotor;

[0010] The annular insulating end cover is radially provided with an oil filling hole and an oil collecting hole at the upper and lower parts respectively. The oil filling hole is connected with the bearing in the bearing chamber through an oil filling pipeline. The bearing chamber shell is provided with an oil drain hole for discharging the oil after lubricating the bearing and flowing back to the oil tank through the oil return pipe installed on the oil collecting hole.

[0011] Furthermore, an insulating layer is provided between the annular insulating end cover and the bearing chamber, and the insulating layer comprises a radial insulating ring between the inner ring of the annular insulating end cover and the bearing chamber and an axial insulating plate between the inner end surface of the annular insulating end cover and the bearing chamber.

[0012] Furthermore, the radial insulating ring is a weft-free belt, and the axial insulating plate is a glass cloth plate.

[0013] Furthermore, the sealing mechanism is located between the inner end surface of the annular insulating end cover and the outer ring of the bearing chamber, and is used to prevent the discharged oil from entering the insulating layer;

[0014] The sealing mechanism comprises a first sealing ring embedded in the outer ring of the bearing chamber, a second sealing ring embedded in the inner end surface, and a sealing ring that squeezes the first sealing ring and the second sealing ring. The sealing ring is fixedly connected to the inner end surface by a fastener.

[0015] Furthermore, the gaps between the sealing ring, the annular insulating end cover and the bearing chamber are all coated with waterproof sealant.

[0016] Furthermore, a filter screen for filtering lubricating oil is provided at the oil filling port on the oil filling hole.

[0017] Furthermore, the oil drain hole consists of a straight hole and an inclined hole, one end of the straight hole is connected to the bearing, and the other end is connected to the inclined hole, and the angle between the inclined hole and the horizontal plane is an acute angle.

[0018] Furthermore, after the annular insulating end cover is assembled with the bearing chamber, a vacuum pressure dip coating treatment is performed.

[0019] Furthermore, the annular insulating end cover and the bearing chamber are treated with paint and then subjected to water immersion testing.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention discloses an insulating end cover structure suitable for an offshore wind turbine. The present invention arranges an insulating layer between the annular insulating end cover and the bearing chamber, blocks the path of the shaft current through the insulating layer, eliminates or reduces the shaft voltage, avoids the shaft current generated at the bearing oil film, and further causes the bearing to be damaged by electrical corrosion; in addition, after the annular insulating end cover and the bearing chamber are assembled, a vacuum pressure varnishing treatment is performed, that is, the gap between the two is filled with insulating varnish, and the entire insulating layer is covered and wrapped at the same time to form a dense protective layer to prevent moisture from entering the interior of the structure; secondly, a sealing mechanism composed of a sealing ring, a sealing ring and a sealant is arranged on the side of the insulating layer close to the lubricating oil, that is, the insulating end cover structure prevents moisture from entering the insulating layer through a variety of measures, and significantly improves the reliability of the insulating end cover.

[0022] 2. The present invention provides an insulating end cover structure suitable for offshore wind turbines. After the annular insulating end cover and the bearing chamber are treated with paint, a water immersion test is performed. After long-term immersion, if the insulation resistance still meets the standard, fine processing is performed without disassembly, thereby ensuring the moisture resistance of the structure.

[0023] 3. The present invention is an insulating end cover structure suitable for offshore wind turbines. The insulating end cover can be made into an insulating end cover of a suitable size according to the size of the motor, and can be assembled on permanent magnet, double-fed, asynchronous and other offshore generators, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 It is a schematic diagram of the overall structure of the insulating end cover structure of the present invention;

[0027] Figure 2 It is a schematic cross-sectional view of the overall structure of the insulating end cover structure of the present invention;

[0028] Figure 3 It is a cross-sectional schematic diagram of the connection structure between the annular insulating end cover and the bearing chamber of the present invention;

[0029] Figure 4 It is a schematic structural diagram of the annular insulating end cover of the present invention;

[0030] Among them: 1 is an annular insulating end cover; 2 is a bearing chamber; 3 is a sealing mechanism; 4 is a bearing; 5 is a rotor; 6 is a stator; 7 is a grounding brush; 8 is an oil filling pipeline; 9 is an oil return pipe; 10 is an insulating layer; 11 is an inner ring; 12 is an inner end face; 13 is an outer end face; 14 is an oil filling hole; 15 is an oil collecting hole; 21 is an oil drain hole; 31 is a first sealing ring; 32 is a second sealing ring; 33 is a sealing ring; 34 is a waterproof sealant; 81 is an insulating joint; 101 is a radial insulating ring; 102 is an axial insulating plate; 121 is an annular groove; 141 is an oil filling port; 142 is a filter screen. DETAILED DESCRIPTION

[0031] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices consistent with some aspects of the present invention as detailed in the appended claims.

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0033] See also Figures 1 to 4 As shown, the present invention provides an insulating end cover structure suitable for an offshore wind turbine, comprising an annular insulating end cover 1, wherein a bearing chamber 2 is installed at the inner ring 11 and the inner end surface 12 of the annular insulating end cover 1, and a sealing mechanism 3 is provided at the connection between the annular insulating end cover 1 and the bearing chamber 2, and a bearing 4 is provided in the bearing chamber 2, and the bearing 4 is movably installed on the circumferential surface of a rotor 5.

[0034] Among them, the annular insulating end cover 1 of the embodiment of the present invention is connected to the stator 6 on the outer end surface 13 on the right side, and a grounding brush 7 is installed on the stator 6. The end of the grounding brush 7 is in contact with the circumferential surface of the rotor 5, which is used to conduct the shaft current between the stator 6 and the rotor 5; the annular insulating end cover 1 is radially provided with an oil filling hole 14 and an oil collecting hole 15 at the upper and lower parts, respectively, the oil filling hole 14 is connected to the bearing 4 in the bearing chamber 2 through the oil filling pipeline 8, and the bearing chamber 2 shell is provided with an oil drain hole 21, which is used to discharge the oil after lubricating the bearing 4 and flow back to the oil tank through the return oil pipe 9 installed on the oil collecting hole 15.

[0035] Specifically, a filter screen 142 for filtering the lubricating oil is provided at the oil filling port 141 on the oil filling hole 14 to prevent impurities from entering and damaging the bearing 4, thereby improving the cleanliness of the lubricating oil and the operating reliability of the bearing; in addition, the oil drain hole 21 consists of a straight hole and an inclined hole, one end of the straight hole is connected to the bearing 4, and the other end is connected to the inclined hole, and the angle between the inclined hole and the horizontal plane is an acute angle, thereby ensuring that the lubricating oil can still be discharged smoothly when the generator is installed at an inclination angle.

[0036] Specifically, in the embodiment of the present invention, an insulating layer 10 is provided between the annular insulating end cover 1 and the bearing chamber 2, and the insulating layer 10 includes a radial insulating ring 101 between the inner ring 11 of the annular insulating end cover 1 and the bearing chamber 2, and an axial insulating plate 102 between the inner end surface 12 of the annular insulating end cover 1 and the bearing chamber 2. Preferably, the radial insulating ring 101 is a weft-free belt, and the axial insulating plate 102 is a glass cloth plate. By providing the insulating layer 10, the annular insulating end cover 1 and the bearing chamber 2 are separated, the path of the shaft current is blocked, and the grounding device is avoided to be provided at the same time, the shaft current is conducted, the shaft voltage is eliminated or reduced, and the shaft current is avoided to be generated at the oil film of the bearing 4, which causes the bearing to be damaged by electrical corrosion. In addition, after the annular insulating end cover 1 of the present invention is assembled with the bearing chamber 2, a vacuum pressure varnishing treatment is first performed to fill the gap between the two metal materials with insulating varnish, and at the same time cover and wrap the entire insulating layer 10 to form a dense protective layer to prevent moisture from entering and causing the insulating layer 10 to fail; after the varnishing treatment, a water immersion test is performed, and after a long period of immersion, if the insulation resistance still meets the standard, fine processing is performed without disassembling the assembly relationship, thereby ensuring the moisture resistance of the structure.

[0037] An insulating joint 81 is provided on the oil filling pipeline 8 to prevent the oil filling pipe from short-circuiting the insulating layer 10 of the insulating end cover.

[0038] The sealing mechanism 3 of the embodiment of the present invention is located between the inner end surface 12 of the annular insulating end cover 1 and the outer ring of the bearing chamber 12, and is used to prevent the discharged oil from entering the insulating layer 9; specifically,

[0039] The sealing mechanism 3 includes a first sealing ring 31 embedded in the outer ring of the bearing chamber 2 (a groove is provided on the outer ring) and a second sealing ring 32 embedded in the inner end surface 12 (a groove 121 is provided on the inner end surface), and a sealing ring 33 that squeezes the first sealing ring 31 and the second sealing ring 32. The sealing ring 33 is fixedly connected to the inner end surface 12 by evenly arranged fasteners to prevent lubricating oil from entering the insulating layer 10, because the entry of contaminated oil will cause the insulating layer 10 to fail. Preferably, the first sealing ring 31 and the second sealing ring 32 are both oil-resistant, high-temperature-resistant, wear-resistant, and fatigue-resistant O-ring sealing rings made of silicone rubber or fluororubber.

[0040] In order to further improve the sealing effect, in the embodiment of the present invention, waterproof sealant 34 is coated on the exposed gaps between the sealing ring 33 and the annular insulating end cover 1 and the bearing chamber 2 to prevent moisture from entering the insulating layer 10 and causing a decrease in insulation performance.

[0041] Based on the above insulating end cover structure, the present invention can be manufactured into insulating end covers of suitable sizes according to the size of the motor, and assembled on permanent magnet, double-fed, asynchronous and other offshore generators.

[0042] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part adopt conventional means such as mature machining and welding in the prior art. The machinery and parts adopt conventional models in the prior art and will not be described in detail here. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0043] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0044] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. An insulating end cover structure suitable for an offshore wind turbine, comprising an annular insulating end cover (1), a bearing chamber (2) being installed at an inner ring (11) and an inner end surface (12) of the annular insulating end cover (1), and a sealing mechanism (3) being provided at a connection between the annular insulating end cover (1) and the bearing chamber (2), a bearing (4) being provided in the bearing chamber (2), and the bearing (4) being movably installed on a circumferential surface of a rotor (5); wherein: The outer end surface (13) of the annular insulating end cover (1) is connected to a stator (6), and a grounding brush (7) is installed on the stator (6). The end of the grounding brush (7) contacts the circumferential surface of the rotor (5) and is used to conduct the shaft current between the stator (6) and the rotor (5). The annular insulating end cover (1) is provided with an oil injection hole (14) and an oil collecting hole (15) at the upper and lower parts thereof in a radial direction. The oil injection hole (14) is connected to the bearing (4) in the bearing chamber (2) through an oil injection pipeline (8). The shell of the bearing chamber (2) is provided with an oil discharge hole (21) for discharging the oil after lubricating the bearing (4) and returning the oil to the oil tank through an oil return pipe (9) installed on the oil collecting hole (15). An insulating layer (10) is provided between the annular insulating end cover (1) and the bearing chamber (2), the insulating layer (10) comprising a radial insulating ring (101) between the inner ring (11) of the annular insulating end cover (1) and the bearing chamber (2), and an axial insulating plate (102) between the inner end surface (12) of the annular insulating end cover (1) and the bearing chamber (2); After the annular insulating end cover (1) and the bearing chamber (2) are assembled, a vacuum pressure varnishing treatment is performed; The annular insulating end cover (1) and the bearing chamber (2) are subjected to a paint treatment and then subjected to a water immersion test; The sealing mechanism (3) is located between the inner end surface (12) of the annular insulating end cover (1) and the outer ring of the bearing chamber (2), and is used to prevent the discharged oil from entering the insulating layer (10); the sealing mechanism (3) comprises a first sealing ring (31) embedded in the outer ring of the bearing chamber (2), a second sealing ring (32) embedded in the inner end surface (12), and a sealing ring (33) that squeezes the first sealing ring (31) and the second sealing ring (32), and the sealing ring (33) is fixedly connected to the inner end surface (12) by a fastener; The gaps between the sealing ring (33), the annular insulating end cover (1) and the bearing chamber (2) are all coated with waterproof sealant (34).

2. The insulating end cover structure suitable for an offshore wind turbine according to claim 1, characterized in that: The radial insulating ring (101) is a weft-free belt, and the axial insulating plate (102) is a glass cloth plate.

3. The insulating end cover structure suitable for an offshore wind turbine according to claim 1, characterized in that: A filter screen (142) for filtering lubricating oil is provided at the oil filling port (141) on the oil filling hole (14).

4. The insulating end cover structure suitable for an offshore wind turbine according to claim 1, characterized in that: The oil injection pipeline (8) is provided with an insulating joint (81).

5. The insulating end cover structure suitable for an offshore wind turbine according to claim 1, characterized in that: The oil drain hole (21) consists of a straight hole and an inclined hole. One end of the straight hole is connected to the bearing (4), and the other end is connected to the inclined hole. The angle between the inclined hole and the horizontal plane is an acute angle.

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