Air pressure balance structure and wind generating set

Abstract

The invention relates to an air pressure balance structure which comprises a gearbox rear box body, a generator shell, a gearbox output shaft, a first shell and a second shell, a generator cavity is defined by the generator shell and the gearbox rear box body, and a sealing structure is arranged between the gearbox output shaft and an output shaft mounting hole. The first shell is fixedly connected with a rear box body of the gear box, the second shell is fixedly connected with an output shaft of the gear box, the first shell and the second shell form a wind shielding structure, the wind shielding structure divides a cavity of the generator into an inner side space and an outer side space, a rotating gap is formed between the first shell and the second shell, and blades are arranged on the second shell. When the second shell rotates along with the output shaft of the gearbox, the blades rotate so as to generate balance pressure opposite to pressure formed by generator cooling airflow in the outer side space in the rotating gap. The invention further provides a wind generating set. The invention can prevent the gearbox output shaft sealing area from generating positive pressure or negative pressure due to the influence of generator cooling airflow.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, specifically to a pressure balance structure and a wind turbine generator set. Background Technology

[0002] As competition in the wind power market intensifies and wind power equipment prices continue to decline, wind turbine manufacturers are constantly reducing manufacturing costs while ensuring performance meets requirements. In the structure of a wind turbine, the cost and performance of the drivetrain directly determine the overall cost and performance of the turbine.

[0003] like Figure 4 As shown, the drivetrain of a traditional wind turbine generator set includes components such as a hub 101, main shaft 104, main bearing 102, main bearing housing 103, input coupling 105, gearbox 106, output coupling 107, and generator 108. To improve market competitiveness, the development trend of wind turbine generator set drivetrains is to integrate the main shaft, main bearing, main bearing housing, gearbox, and generator into a single structure, thereby eliminating some couplings. This reduces the number of parts and shortens the drivetrain length, ultimately reducing the weight and cost of the wind turbine generator set. Wind turbine generator sets adopting this integrated solution are typically called fully integrated drivetrain wind turbine generator sets. In existing technologies, there are also semi-integrated drivetrains that integrate the gearbox and generator into a single structure, while leaving the other components separate.

[0004] like Figure 5 As shown, the fully integrated transmission chain includes components such as hub 201, front spindle bearing 202, spindle 203, spindle bearing housing 204, bolt group 205, rear spindle bearing 206, front gearbox housing 207, first-stage planetary carrier 208, rear gearbox housing 209, gearbox output shaft 210, generator rotor 211, and generator stator 212. The gearbox input shaft is rigidly connected to the rear end of the spindle 203 via bolt group 205 (or bolt + pin), enabling the torque of the spindle 203 to be transmitted to the gearbox. The front gearbox housing 207 is rigidly connected to the spindle bearing housing 204 as a whole via bolts, and the rear gearbox housing 209 is rigidly connected to the generator housing as a whole. The generator stator 212 is fixed inside the generator housing, and the generator rotor 211 is directly connected to the gearbox output shaft 210 or connected via a coupling.

[0005] In a semi-integrated drivetrain, the gearbox is not integrated with the main shaft, but the rear housing of the gearbox is rigidly connected to the generator housing as a whole, and the generator rotor is integrated with the gearbox output shaft as a whole.

[0006] Compared to traditional wind turbine drivetrains, fully integrated or semi-integrated drivetrains have the following characteristics: the generator is no longer a separate component; the generator stator and rotor are respectively suspended and mounted at the rear end of the gearbox, forming a single integrated gearbox-generator assembly. This type of gearbox-generator integrated assembly has the advantages of compact structure, light weight, and low cost.

[0007] However, this gearbox-generator integrated assembly also has disadvantages. To prevent the generator from overheating during operation, air circulation is required to cool the internal components. Since the generator stator and rotor are mounted on the rear housing of the gearbox and the gearbox output shaft, respectively, the gearbox output shaft and sealing end caps, among other components, will be affected by the generator's cooling air.

[0008] like Figure 6 As shown, when the generator is operating, the generator cooling airflow generated by the generator air cooler 213 flows in the direction of the arrow. It first enters the area between the generator and the gearbox rear housing, where the gearbox output shaft 210 and sealing end caps are located. Then, it flows through the air gap between the generator stator 212 and the generator rotor 211, carrying away the generator's operating heat. When the generator cooling airflow acts on the output shaft sealing structure, such as the sealing end caps, it generates positive pressure at the gearbox output shaft 210. When the output shaft sealing structure at the gearbox output shaft 210 cannot withstand the positive pressure of the generator cooling airflow, the generator cooling airflow in this area easily blows into the gearbox and mixes with the lubricating oil droplets and oil mist sprayed inside the gearbox. This mixture then overflows from the air filter, input end caps, and other locations in the gearbox, causing lubricating oil leakage. The leaked lubricating oil will contaminate the engine compartment, causing safety hazards or other component failures. In severe cases, the leaked lubricating oil will further leak outside the engine compartment, causing an environmental pollution accident.

[0009] When the generator cooling airflow is as described above Figure 6 When the direction of the middle arrow is opposite, negative pressure will be generated at the gearbox output shaft 210. When the sealing structure at the gearbox output shaft 210 cannot withstand the negative pressure of the generator cooling airflow, the negative pressure will cause the air inside the gearbox to carry lubricating oil or oil mist and leak from the output shaft seal to the rear gearbox housing area, thereby contaminating the generator and engine compartment, causing generator failure, engine compartment contamination and other accidents.

[0010] Because the gearbox output shaft and sealing end cap are located at the rear of the gearbox and surrounded by the generator, repairing or replacing them on-site in the engine room is extremely difficult in the event of an oil leak. If the leak is severe, large cranes (on land) or lifting vessels (at sea) may be required to disassemble and lift the gearbox-generator assembly from the engine room, transport it to the manufacturing plant, disassemble the generator from the rear of the gearbox, and then perform repairs. After repairs, it must be transported back to the site and reassembled using large cranes or lifting vessels. The entire process involves a large workload and extremely high lifting costs, resulting in high overall repair costs. Furthermore, because this method involves disassembly, transportation, repair, and reassembly, the entire repair cycle is time-consuming, and downtime leads to significant power generation losses.

[0011] In summary, wind turbine generator sets using fully integrated or semi-integrated drive trains face the following technical problems: the generator cooling airflow will generate positive or negative pressure at the gearbox output shaft, leading to oil leakage in the gearbox, and consequently resulting in huge maintenance costs and power generation losses. Summary of the Invention

[0012] The purpose of this invention is to propose a pressure balance structure and a wind turbine generator set to reduce or even eliminate gearbox oil leakage caused by positive or negative pressure generated by the generator cooling airflow at the gearbox output shaft.

[0013] This invention discloses a pressure balancing structure applied to a wind turbine generator set. The pressure balancing structure includes a gearbox rear housing, a generator housing, a gearbox output shaft, a first housing, and a second housing. The generator housing is connected to the gearbox rear housing, and the generator housing and the gearbox rear housing define a generator cavity. An output shaft mounting hole is provided on one side of the gearbox rear housing near the generator cavity. The gearbox output shaft is rotatably supported in the output shaft mounting hole, and a sealing structure is provided between the gearbox output shaft and the output shaft mounting hole. The first housing is fixedly connected to the gearbox rear housing. The second housing is fixedly connected to the gearbox output shaft. The first housing and the second housing together form a windproof structure. The windproof structure divides the generator cavity into an inner space located inside the windproof structure and an outer space located outside the windproof structure. The sealing structure is located in the inner space. A rotation gap is provided between the first housing and the second housing. A blade is provided on the second housing. When the second housing rotates with the gearbox output shaft, the blade rotates with the second housing to generate a balanced pressure at the rotation gap that is opposite in direction to the pressure formed by the generator cooling airflow in the outer space.

[0014] Optionally, the first housing is provided with an annular groove at one end near the rotational clearance, and the blade extends into the annular groove.

[0015] Optionally, the output end of the gearbox output shaft extends to the right from the output shaft mounting hole. The second housing includes a disc-shaped component fixedly connected to the output end of the gearbox output shaft. The first housing includes an outer peripheral wall with an open right end. The rotation clearance is disposed between the open right end of the outer peripheral wall and the left side of the disc-shaped component. The annular groove is disposed on the inner periphery of the open right end of the outer peripheral wall, and the opening of the annular groove faces to the right.

[0016] Optionally, the first housing further includes an inner flange connected to the left end of the outer peripheral wall, the inner flange being fixedly connected to the rear housing of the gearbox.

[0017] Optionally, the disc-shaped component is provided with a plurality of first flange holes for fixing and connecting the generator rotor bracket.

[0018] Optionally, the inner circumferential surface of the generator rotor bracket is clearance-fitted with the right end of the outer circumferential wall.

[0019] Optionally, the second housing is provided with a plurality of blades, which are evenly distributed in the circumferential direction of the second housing.

[0020] Optionally, the multiple blades and the second housing constitute a centrifugal impeller.

[0021] Optionally, the second housing is provided with a vent for connecting the inner space with the nacelle of the wind turbine generator set.

[0022] The present invention also proposes a wind turbine generator set, including the pressure balance structure described in any of the above claims.

[0023] The air pressure balance structure proposed in this invention can isolate the generator cooling airflow circulation channel from the gearbox output shaft sealing area, and can generate a balanced pressure opposite to the pressure direction formed by the generator cooling airflow, thereby preventing the gearbox output shaft sealing area from being affected by the generator cooling airflow and generating harmful positive or negative pressure. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the pressure balance structure described in some embodiments; Figure 2 for Figure 1 A magnified view of a portion of the view; Figure 3 This is a schematic diagram of the structure of the first and second housings described in some embodiments; Figure 4 This is a schematic diagram of the transmission chain of a conventional wind turbine generator set as described in the background art. Figure 5This is a schematic diagram of the fully integrated transmission chain described in the background art; Figure 6 This is a schematic diagram of the flow direction of the generator cooling airflow described in the background art.

[0025] The part numbers in the figure are as follows: 301—Gearbox rear housing, 302—Gearbox output shaft, 303—Sealed end cover, 304—Bearing, 305—First housing, 306—Second housing, 307—Outer peripheral wall, 308—Inner flange, 309—Slotted component, 310—Cavity, 311—Disc-shaped component, 312—Blade, 313—Ventilation hole, 314—Rotation clearance, 315—Inner space, 316—Second bolt, 317—Third bolt, 318—Generator rotor bracket, 319—First bolt, 320—Second flange hole, 321—First flange hole, 322—Outer space. Detailed Implementation

[0026] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0027] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0028] like Figures 1 to 3The diagram illustrates a pressure balancing structure applied to a wind turbine generator set. The pressure balancing structure includes a gearbox rear housing 301, a generator housing, a gearbox output shaft 302, a first housing 305, and a second housing 306. The generator housing is connected to the gearbox rear housing 301, and the generator housing and gearbox rear housing 301 define a generator cavity. The gearbox rear housing 301 has an output shaft mounting hole on one side near the generator cavity. The gearbox output shaft 302 is rotatably supported in the output shaft mounting hole via a bearing 304. A sealing structure is provided between the gearbox output shaft 302 and the output shaft mounting hole. The first housing 305 is fixedly connected to the gearbox rear housing 301, and the second housing 306... The body 306 is fixedly connected to the gearbox output shaft 302. The first housing 305 and the second housing 306 together form a windproof structure. The windproof structure divides the generator cavity into an inner space 315 located inside the windproof structure and an outer space 322 located outside the windproof structure. The sealing structure is located in the inner space 315. A rotation gap 314 is provided between the first housing 305 and the second housing 306. A blade 312 is provided on the second housing 306. When the second housing 306 rotates with the gearbox output shaft 302, the blade 312 rotates with the second housing 306 to generate a balanced pressure at the rotation gap 314 that is opposite in direction to the pressure formed by the generator cooling airflow in the outer space 322.

[0029] By adopting the above technical solution, a pressure balance structure is formed on the outside of the gearbox output shaft 302. Firstly, the wind-blocking structure of the first housing 305 and the second housing 306 separates the inner space 315 from the outer space 322, reducing the amount of generator cooling airflow entering the inner space 315. Secondly, when the wind turbine is operating, the blades 312 rotate with the second housing 306, generating a balancing pressure at the rotation gap 314 that is opposite in direction to the pressure formed by the generator cooling airflow in the outer space 322, creating a counteracting effect. This achieves non-contact pressure isolation between the inner space 315 and the outer space 322. In other words, by adopting the above-mentioned pressure balance structure, the generator cooling airflow circulation channel can be isolated from the sealed area of ​​the gearbox output shaft 302, generating a balancing pressure opposite in direction to the pressure formed by the generator cooling airflow. This prevents the sealed area of ​​the gearbox output shaft 302 from being affected by the generator cooling airflow, thus reducing or even avoiding gearbox oil leakage caused by the generator cooling airflow.

[0030] More specifically, the rotational clearance 314 between the first housing 305 and the second housing 306 is a clearance formed to allow the second housing 306 to rotate. This rotational clearance 314 can be designed to be small, for example, 0.1-0.5 mm. The small clearance fit between the first housing 305 and the second housing 306 forms a small clearance sealing structure, which has a certain sealing and isolation effect. It can isolate the gearbox output shaft 302 area from the generator cooling airflow area, that is, divide the generator cavity into an inner space 315 and an outer space 322. Most of the generator cooling airflow can be confined to the outer space 322, effectively reducing the generator cooling airflow leakage into the inner space 315.

[0031] More specifically, during rotation, the blade 312 generates an airflow at the rotation gap 314 that is at a pressure equivalent to but opposite in direction to the generator cooling airflow. This generates a balanced pressure at the rotation gap 314 that is opposite in direction to the pressure generated by the generator cooling airflow in the outer space 322. This separates the outer space 322 through which the generator cooling airflow flows from the inner space 315 where the gearbox output shaft 302 sealing area is located, effectively preventing the generator cooling airflow from generating harmful positive or negative pressure in the gearbox output shaft 302 area.

[0032] In practical implementation, the sealing structure includes a sealing end cap 303.

[0033] In some embodiments, an annular groove is provided at one end of the first housing 305 near the rotational clearance 314, and the blade 312 extends into the annular groove. The annular groove and the blade 312 cooperate to better form a balanced pressure.

[0034] As a specific example, the output end of the gearbox output shaft 302 extends to the right from the output shaft mounting hole. The second housing 306 includes a disc-shaped member 311 fixedly connected to the output end of the gearbox output shaft 302. The first housing 305 includes an outer peripheral wall 307 with an open right end. A rotation gap 314 is disposed between the right end opening of the outer peripheral wall 307 and the left side of the disc-shaped member 311. An annular groove is disposed on the inner periphery of the right end opening of the outer peripheral wall 307, with the groove opening facing to the right.

[0035] In some embodiments, the first housing 305 further includes an inner flange 308 connected to the left end of the outer peripheral wall 307, and the inner flange 308 is fixedly connected to the gearbox rear housing 301. The inner flange 308 is provided with a plurality of second flange holes 320, and a plurality of second bolts 316, each engaging with a plurality of second flange holes 320, are used to fix the inner flange 308 to the gearbox rear housing 301, thereby fixing the first housing 305 to the gearbox rear housing 301. In a specific implementation, the inner flange 308 has an annular structure, and the annular inner flange 308 is tightly connected to the gearbox rear housing 301, forming a certain degree of seal.

[0036] As a specific example, a groove-shaped member 309 is fixedly connected to the inner periphery of the right end of the outer peripheral wall 307, and the groove-shaped member 309 and the right end of the outer peripheral wall 307 form a groove cavity 310 of an annular groove.

[0037] In some embodiments, the disc-shaped member 311 is provided with a plurality of first flange holes 321 for fixing and connecting the generator rotor support 318. The disc-shaped member 311 forms a transition flange, which helps to reduce the difficulty of disassembling and assembling the generator rotor. In a specific implementation, the generator rotor support 318 is fixedly connected to the disc-shaped member 311 by a plurality of first bolts 319 that mate with the plurality of first flange holes 321, and the disc-shaped member 311 is fixedly connected to the gearbox output shaft 302 by a plurality of third bolts 317.

[0038] In some embodiments, the inner circumferential surface of the generator rotor support 318 is clearance-fitted with the right end of the outer circumferential wall 307. The clearance between the inner circumferential surface of the generator rotor support 318 and the right end of the outer circumferential wall 307, along with the rotational clearance 314, forms a tortuous clearance, which can further reduce the generator cooling airflow entering the inner space 315. In specific implementations, the generator rotor support 318 needs to rotate, therefore the size of the clearance between the two needs to ensure the smooth rotation of the generator rotor support 318.

[0039] In some embodiments, a plurality of blades 312 are provided on the second housing 306, and the plurality of blades 312 are evenly distributed in the circumferential direction of the second housing 306. The plurality of blades 312 can form a more uniform balanced pressure. The number, shape, size, and distribution diameter of the blades 312 can be determined according to the wind pressure to be balanced.

[0040] In some embodiments, multiple blades 312 and the second housing 306 constitute a centrifugal impeller. The rotation of the centrifugal impeller generates outward air pressure, which is opposite in direction to the inward air pressure generated by the generator cooling airflow, achieving a counteracting effect. As a preferred embodiment, the centrifugal impeller and the annular groove on the first housing 305 constitute a centrifugal pressurization structure, which can better form air pressure isolation between the inner space 315 and the outer space 322.

[0041] By employing the aforementioned pressure balancing structure, due to the rotational clearance 314 between the first housing 305 and the second housing 306, the generator cooling airflow can still leak from this clearance 314 into the inner space 315, resulting in a slight adverse effect. To mitigate or eliminate this adverse effect, in some embodiments, the second housing 306 is provided with a vent 313 for connecting the inner space 315 with the nacelle of the wind turbine generator set. After a small amount of generator cooling airflow leaks into the inner space 315, it can enter the nacelle environment through the vent 313, thereby ensuring that the air pressure in the area of ​​the sealing end cover 303 of the gearbox output shaft 302 is basically the same as the atmospheric pressure of the nacelle, eliminating the possibility of gearbox oil leakage due to positive or negative air pressure in this area. In specific implementations, a channel for connecting the vent 313 and the nacelle can be formed on the outside of the second housing 306, and this channel can be formed by a cylindrical component disposed in the generator chamber.

[0042] This application reduces the possibility of gearbox oil leakage from multiple dimensions, thereby improving the operational reliability of wind turbine generator sets and ultimately enhancing their competitiveness.

[0043] As a specific example, the first housing 305 is a thin-shell structure of rotation, tightly fixed to the rear housing 301 of the gearbox, concentric with the gearbox output shaft 302 and not rotating; the second housing 306 is directly integrated with the generator rotor transition flange and rotates together with the gearbox output shaft 302. The first housing 305 and the second housing 306 are concentrically fitted with a small clearance to form a small-clearance sealing structure. Multiple blades 312 are directly designed on the generator rotor transition flange, evenly distributed around the circumference to form a booster impeller. The booster impeller is embedded in the annular groove of the first housing 305 to form a centrifugal booster structure. Vent holes 313 are designed on the generator rotor transition flange, evenly distributed around the circumference, to achieve communication with the internal environment of the engine compartment and maintain consistent air pressure.

[0044] The present invention also proposes a wind turbine generator set, including the pressure balance structure described in any of the above claims.

[0045] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., means that a specific feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0046] In the description of this invention, it should be understood that the terms "left," "right," etc., indicate directions based on the attached... Figure 1 The coordinate system used in this invention is for the purpose of facilitating and simplifying the description of the invention, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the invention.

Claims

1. A pressure balancing structure, characterized in that, The pressure balancing structure is applied to a wind turbine generator set. The pressure balancing structure includes a gearbox rear housing, a generator housing, a gearbox output shaft, a first housing, and a second housing. The generator housing is connected to the gearbox rear housing, and the generator housing and gearbox rear housing define a generator cavity. The gearbox rear housing has an output shaft mounting hole on one side near the generator cavity. The gearbox output shaft is rotatably supported in the output shaft mounting hole. A sealing structure is provided between the gearbox output shaft and the output shaft mounting hole. The first housing is fixedly connected to the gearbox rear housing, and the second housing is... The gearbox output shaft is fixedly connected. The first housing and the second housing together form a windproof structure. The windproof structure divides the generator cavity into an inner space located inside the windproof structure and an outer space located outside the windproof structure. The sealing structure is located in the inner space. A rotation gap is provided between the first housing and the second housing. A blade is provided on the second housing. When the second housing rotates with the gearbox output shaft, the blade rotates with the second housing to generate a balanced pressure at the rotation gap that is opposite in direction to the pressure formed by the generator cooling airflow in the outer space.

2. The pressure balance structure according to claim 1, characterized in that, The first housing has an annular groove at one end near the rotational clearance, and the blade extends into the annular groove.

3. The pressure balance structure according to claim 2, characterized in that, The output end of the gearbox output shaft extends to the right from the output shaft mounting hole. The second housing includes a disc-shaped component fixedly connected to the output end of the gearbox output shaft. The first housing includes an outer peripheral wall with an open right end. The rotation clearance is located between the open right end of the outer peripheral wall and the left side of the disc-shaped component. The annular groove is located on the inner periphery of the open right end of the outer peripheral wall, and the opening of the annular groove faces to the right.

4. The pressure balance structure according to claim 3, characterized in that, The first housing also includes an inner flange connected to the left end of the outer peripheral wall, and the inner flange is fixedly connected to the rear housing of the gearbox.

5. The pressure balance structure according to claim 3, characterized in that, The disc-shaped component is provided with multiple first flange holes for fixing and connecting the generator rotor bracket.

6. The pressure balance structure according to claim 5, characterized in that, The inner circumferential surface of the generator rotor support is clearance-fitted with the right end of the outer circumferential wall.

7. The pressure balance structure according to claim 1, characterized in that, The second housing is provided with a plurality of blades, which are evenly distributed in the circumferential direction of the second housing.

8. The pressure balance structure according to claim 7, characterized in that, The multiple blades and the second housing constitute a centrifugal impeller.

9. The pressure balance structure according to claim 1, characterized in that, The second housing is provided with a vent for connecting the inner space with the nacelle of the wind turbine generator set.

10. A wind turbine generator set, characterized in that, Includes the pressure balance structure as described in any one of claims 1-9.

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