Bearing unit for a wind turbine gearbox

Abstract

The application provides a bearing unit for a wind power gear box, the bearing unit (100) comprises a bearing inner ring (1), an outer periphery of the bearing inner ring (1) is provided with an annular raceway (11); a retainer (3) is arranged on the radially outer side of the bearing inner ring (1), the retainer (3) comprises two retainer rings (31) and a plurality of pin shafts (32), the plurality of pin shafts (32) are connected to the retainer rings (31), the plurality of pin shafts (32) extend along the axial direction (A) of the bearing unit (100) and are arranged along the circumferential direction (C) of the bearing unit (100); and cylindrical rollers (2) are rotatably connected to the retainer (3) around the pin shafts (32), the diameter of the cylindrical rollers (2) is 25-50 mm, and the ratio of the axial length of the cylindrical rollers (2) to the diameter is 3.2-13.

Description

Technical Field

[0001] This application belongs to the field of wind turbine gearbox technology, and specifically relates to a bearing unit for wind turbine gearboxes. Background Technology

[0002] Achieving price parity between wind power and thermal power, and reducing the levelized cost of energy (LCoE), remains a major pressure facing the wind power industry. Due to weight restrictions at the top of the wind turbine tower and the maximum transport size of components, the torque density of the wind turbine gearbox directly affects LCoE; therefore, improving the torque density of wind turbine gearboxes has become particularly urgent.

[0003] Mainstream wind turbine gearboxes typically consist of two or more stages of planetary gears. Increasing the number of planetary gears improves torque density because a larger number of planetary gears reduces the contact stress level at the individual gear contact surfaces, allowing for a significant reduction in the diameter of the planetary gears and gear rings. This has led to a trend in recent years where wind turbine megawatt ratings have been increasing in size, while wind turbine gearbox designs have been trending towards miniaturization and lightweighting. This design trend results in a significant reduction in gearbox size, while also reducing the space available for bearing installation.

[0004] Existing bearing assemblies for wind turbine gearboxes consist of two bearing units, which can be arranged symmetrically. Each bearing unit is a double-row cylindrical roller bearing. The double-row cylindrical roller bearing includes an inner ring and cylindrical rollers. The inner ring has inner ring flanges separating the two rows of cylindrical rollers, and inner ring flanges are also located at both ends of the bearing unit. In other words, a single double-row cylindrical roller bearing has three inner ring flanges on its inner ring, forming two raceways.

[0005] The performance of bearings designed to the current dimensions (especially the contact stress on the bearing raceways) is already close to the upper limit required by wind turbine gearbox design standards. Further reducing bearing size to accommodate smaller spaces will make it difficult to meet the design standards' requirements for bearing contact stress, and the theoretical calculated life of the bearings will decrease dramatically, failing to meet the life requirements of planetary gear bearings in wind turbine gearboxes. Furthermore, current cylindrical roller bearing designs fail to fully utilize axial space to bear loads, nor do they make the most of radial space. In some cases, the bearing's effective load-bearing component occupies only about 75% of the bearing mounting area volume.

[0006] In other fields such as rolling mills and automotive transmissions, to improve the load-carrying capacity or lifespan of cylindrical roller bearings, relevant patent documents such as CN219139627U and CN210218408U have disclosed designs that eliminate the intermediate flange and employ two or more rows of rollers arranged side-by-side on a single raceway. However, in wind turbine gearboxes, there have never been similar designs or application examples. Moreover, under the existing design structural parameters and load conditions of wind turbine gearboxes, a design that simply arranges two or more rows of conventional rollers side-by-side cannot enable the bearing to achieve the required load-carrying capacity. This is because the design structure of wind turbine gearboxes has specific application requirements for the outer diameter and width ratio of planetary gear bearings, requirements that have not been fully met in designs from other fields. Utility Model Content

[0007] This application aims to provide a bearing unit for wind turbine gearboxes that adapts to the load-bearing capacity requirements of wind turbine gearboxes.

[0008] Embodiments of this application provide a bearing unit for a wind turbine gearbox, the bearing unit comprising:

[0009] The bearing inner ring has an annular raceway on its outer periphery.

[0010] A cage, disposed radially outside the inner ring of the bearing, the cage comprising two cage rings and a plurality of pins connected to the cage rings, the plurality of pins extending axially along the bearing unit and arranged circumferentially along the bearing unit; and

[0011] A cylindrical roller rotatably connected to the cage about the pin, the cylindrical roller having a diameter of 25 to 50 mm and an axial length to diameter ratio of 3.2 to 13.

[0012] In at least one possible implementation, a row of cylindrical rollers is arranged within the raceway, the ratio of the axial length to the diameter of the cylindrical rollers being 4 to 9.

[0013] In at least one possible implementation, at least two rows of cylindrical rollers are arranged side by side along the axial direction within the raceway, the ratio of the axial length to the diameter of the cylindrical rollers being 3.2 to 6.5.

[0014] In at least one possible implementation, the cylindrical rollers are used for direct rolling contact with the inner circumferential surface of the planetary gear, and the bearing unit does not include an outer bearing ring.

[0015] In at least one possible implementation, the two ends of the pin are respectively connected to the two cage rings, the center hole of the cylindrical roller is a through hole, and the pin passes through the cylindrical roller so that the cylindrical roller is sleeved on the pin.

[0016] In at least one possible implementation, the number of cylindrical rollers and pins is the same in the same cage, or the number of cylindrical rollers is greater than the number of pins, and at least some of the cylindrical rollers are not mounted on the pins.

[0017] In at least one possible implementation, one end of the pin is connected to the cage ring, the other end of the pin is a suspended free end, and the pin is inserted into the center hole of the cylindrical roller.

[0018] In at least one possible implementation, the center hole of the cylindrical roller is a blind hole, or

[0019] The central hole of the cylindrical roller is a through hole, or

[0020] The center hole of one part of the cylindrical rollers is a blind hole, while the center hole of the other part of the cylindrical rollers is a through hole.

[0021] In at least one possible implementation, in the same cage, the number of cylindrical rollers is half the number of pins, or the number of cylindrical rollers is greater than half the number of pins, and at least some of the cylindrical rollers are not mounted on the pins.

[0022] In at least one possible implementation, the diameter of the pin is smaller than the inner diameter of the center hole of the cylindrical roller, and a gap is left between the pin and the center hole of the cylindrical roller.

[0023] In at least one possible implementation, the pin includes:

[0024] The first pins at both ends are respectively connected to the cage ring; and

[0025] A second pin, one end of which is connected to the cage ring and the other end of which is a suspended free end,

[0026] The number of the first pins is two or more, and the number of the first pins is less than the number of the second pins.

[0027] By adopting the above technical solution, at least one of the following beneficial effects can be obtained.

[0028] (1) By installing cylindrical rollers through pin shafts, the circumferential clearance of the cylindrical rollers can be reduced, thereby increasing the number of cylindrical rollers, improving the bearing capacity, and meeting the bearing capacity requirements of wind turbine gearboxes.

[0029] (2) The outer circumferential surface of a single bearing inner ring has only one raceway, eliminating the stress caused by dimensional deviations in multiple raceway surfaces. Removing the intermediate flange located in the middle of the raceway allows for more efficient use of axial space, and the entity that effectively bears the load accounts for approximately 90% of the bearing mounting area volume, thus enhancing the bearing's load-bearing capacity.

[0030] (3) The diameter of the cylindrical rollers and the ratio of the axial length to the diameter of the cylindrical rollers have been optimized. The diameter of the cylindrical rollers is smaller, resulting in a larger number of cylindrical rollers in the circumferential direction and a stronger bearing load capacity. Compared with the existing cylindrical roller bearings in wind turbine gearboxes, the bearing capacity is increased by about 20%. In addition, the bearing unit of this application has a smaller overall size than the cylindrical roller bearings in existing wind turbine gearboxes, and has a bearing installation space size that is basically equivalent to that of hydraulic sliding bearings. The cylindrical roller bearings are more compact and smaller in size, and have a lower linear velocity at the same speed. The frictional torque and frictional power consumption are small during the start-up and operation of the wind turbine gearbox. In addition, the weight is also reduced compared with traditional cylindrical roller bearings in wind turbine gearboxes, and the impact inertia is small, making it suitable for acceleration and deceleration conditions. The weight reduction reduces the production cost, achieving a bearing cost that is basically equivalent to that of hydraulic sliding bearings. Attached Figure Description

[0031] Figure 1 A schematic diagram of the structure of a bearing assembly for a wind turbine gearbox according to a first embodiment of this application is shown.

[0032] Figure 2 A schematic diagram of the structure of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a first embodiment of this application is shown.

[0033] Figure 3 A cross-sectional view of a bearing assembly for a wind turbine gearbox according to a first embodiment of this application is shown.

[0034] Figure 4 A cross-sectional view of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a first embodiment of this application is shown.

[0035] Figure 5 A side view of a bearing assembly for a wind turbine gearbox according to a first embodiment of this application is shown.

[0036] Figure 6A schematic diagram of the structure of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a second embodiment of this application is shown.

[0037] Figure 7 A cross-sectional view of a bearing assembly for a wind turbine gearbox according to a second embodiment of this application is shown.

[0038] Figure 8 A cross-sectional view of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a second embodiment of this application is shown.

[0039] Figure 9 A schematic diagram of the structure of a bearing assembly for a wind turbine gearbox according to a third embodiment of this application is shown.

[0040] Figure 10 A schematic diagram of the structure of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a third embodiment of this application is shown.

[0041] Figure 11 A cross-sectional view of a bearing assembly for a wind turbine gearbox according to a third embodiment of this application is shown.

[0042] Figure 12 A cross-sectional view of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a third embodiment of this application is shown.

[0043] Figure 13 A schematic diagram of the structure of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a fourth embodiment of this application is shown.

[0044] Figure 14 A cross-sectional view of a bearing assembly for a wind turbine gearbox according to a fourth embodiment of this application is shown.

[0045] Figure 15 A cross-sectional view of a bearing assembly (partial cylindrical rollers not shown) for a wind turbine gearbox according to a fourth embodiment of this application is shown.

[0046] Explanation of reference numerals in the attached figures

[0047] 1. Bearing inner ring; 11. Raceway; 12. Flange

[0048] 2 Cylindrical rollers

[0049] 3. Cage 31. Cage Ring 32. Pin

[0050] Axial direction C Circumferential direction R Radial direction Detailed Implementation

[0051] To more clearly illustrate the above-mentioned objectives, features, and advantages of this application, specific embodiments of this application are described in detail in conjunction with the accompanying drawings in this section. Besides the embodiments described in this section, this application can also be implemented in other different ways. Those skilled in the art can make corresponding improvements, modifications, and substitutions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed in this section. The scope of protection of this application should be determined by the claims.

[0052] (First Implementation)

[0053] like Figures 1 to 5 As shown, the first embodiment of this application proposes a bearing assembly for a wind turbine gearbox. The wind turbine gearbox is the gearbox of a wind turbine generator. The wind turbine gearbox may include planetary gears with inner bores, and the bearing assembly can be installed into the inner bores of the planetary gears. The bearing assembly may include multiple bearing units 100, and the multiple (e.g., two) bearing units 100 may be arranged along an axial direction A. Each bearing unit 100 may have the same structure and axial dimensions.

[0054] The bearing unit 100 may include an inner bearing ring 1, a plurality of cylindrical rollers 2 and a cage 3, wherein the plurality of cylindrical rollers 2 and the cage 3 are disposed on the outer side of the inner bearing ring 1 in the radial direction R.

[0055] The outer circumference of the inner ring 1 of the bearing may be provided with a raceway 11 and two flanges 12. The raceway 11 is annular, and the two flanges 12 can protrude radially outward from the outer circumference of the inner ring 10. The two flanges 12 are located at the two axial ends of the inner ring 10 (or the raceway 11), and the axial interval between the two flanges 12 forms the raceway 11.

[0056] In the first embodiment of this application, the inner bearing ring 1 of the plurality of bearing units 100 of the bearing assembly can be formed by splicing together the plurality of inner bearing rings 1. In other possible embodiments, the inner bearing rings of the plurality of bearing units 100 of the bearing assembly can be integrally formed.

[0057] The bearing unit 100 can be a cylindrical roller bearing. The cylindrical roller 2 is cylindrical with a central hole, which can be a through hole, for the pin 32 described later to pass through.

[0058] The rolling surface of the cylindrical roller 2 directly rolls into contact with the outer circumferential surface of the inner ring 1 of the bearing (i.e., raceway 11) and the inner circumferential surface of the inner bore of the planetary gear in the wind turbine gearbox. In other words, the bearing assembly does not include the outer ring of a conventional cylindrical roller bearing. The bearing assembly for the wind turbine gearbox eliminates the outer ring of a conventional bearing, reducing the radial dimensions of the entire bearing assembly and the wind turbine gearbox, which is beneficial for the compact radial dimensions of the wind turbine gearbox.

[0059] Furthermore, the diameter Dw of the cylindrical roller can be 25 to 50 mm, and the ratio λ (i.e., the length-to-diameter ratio Lw / Dw) of the axial length Lw of the cylindrical roller 2 can be 3.2 to 13. The range of diameters and the range of ratios of the axial length Lw to the diameter Dw of the cylindrical roller 2 in this application result in a small radial footprint for the cylindrical roller 2, thereby making the envelope diameter of the bearing unit 100 smaller. Therefore, the bearing unit 100 of this application occupies a small radial space overall, and the inner diameter of the matching planetary gear can be smaller, thus greatly reducing the diameter of the planetary gear and allowing for the installation of more planetary gears, thereby increasing the torque density of the wind turbine gearbox. Furthermore, compared to traditional cylindrical rollers, the cylindrical rollers of this application have a larger length-to-diameter ratio and are more slender. Under the same bearing pitch circle diameter, more cylindrical rollers 2 can be placed in the circumferential direction, which improves the rigidity of the overall bearing unit 100. More cylindrical rollers 2 mean more contact area between the bearing inner ring 1, the raceway 11, and the planetary gear. More contact area can distribute the load and reduce the pressure (also known as contact stress) borne by a single cylindrical roller 2 and the raceway 11, thereby improving the bearing's static load capacity, overall load-bearing capacity, and theoretical calculated life to meet the application conditions.

[0060] Preferably, a row of cylindrical rollers 2 is arranged within the raceway 11, and the ratio λ (i.e., length-to-diameter ratio Lw / Dw) of the axial length Lw of the cylindrical roller 2 can be 4 to 9. Alternatively, at least two rows of cylindrical rollers 2 are arranged side-by-side along the axial direction A within the raceway 11, and the ratio λ of the axial length Lw of the cylindrical roller 2 to the diameter Dw can be 3.2 to 6.5. This allows the bearing unit 100 to ensure high bearing load capacity while also meeting the requirements for lightweighting, miniaturization, and cost control in the specific application scenario of wind turbine gearboxes.

[0061] Compared to existing double-row and multi-row roller bearings for wind turbine gearboxes, this application allows for an increase in the axial length Lw of the cylindrical rollers within the same axial space, thus making more efficient use of the axial space used for bearing installation. The axial length Lw of the load-bearing cylindrical rollers occupies a larger proportion of the bearing mounting area (e.g., greater than 90%), which not only meets the requirements for a more compact design but also enhances the bearing's load-bearing capacity and improves load-bearing efficiency. Furthermore, under the same load-bearing requirements, the increased axial length Lw of the cylindrical rollers not only improves the load-bearing capacity but also promotes lower cost, miniaturization, and lighter weight for wind turbine gearboxes using this bearing assembly, contributing to high torque density in wind turbine gearboxes.

[0062] Each bearing unit 100's cage 3 may include two cage rings 31 and multiple pins 32. The two cage rings 31 are respectively a first cage ring and a second cage ring, which are respectively disposed on both axial sides of the cylindrical roller 2. The cage rings 31 are annular, and the pins 32 extend axially, with their axial ends connected to the two cage rings 31 respectively. The multiple pins 32 can be evenly arranged circumferentially C. Optionally, the pins 32 can be connected to the cage rings 31 by welding, riveting, or other methods. Here, such pins can be referred to as first pins.

[0063] The pin 32 can be inserted into the cylindrical roller 2, and the pin 32 can support and position the cylindrical roller 2, for example, by passing the pin 32 through the cylindrical roller 2, allowing the cylindrical roller 2 to rotate around the pin 32. Using the pin 32 for positioning and installation ensures a certain circumferential clearance between the multiple cylindrical rollers 2, and that the multiple cylindrical rollers 2 are evenly distributed in the raceway 11. The cage 3 prevents the cylindrical rollers 2 from colliding and rubbing against each other during the operation of the bearing unit 100, helping to maintain the bearing's accuracy and stability, and making the bearing easy to assemble and maintain.

[0064] The cage 3 in this application is a pin-type cage. Compared to the traditional pocket-type cage, this application eliminates the need for cage-free structures (such as the crossbeam of a pocket-type cage) located between the cylindrical rollers. This allows for smaller clearances between adjacent cylindrical rollers 2 and a larger number of cylindrical rollers 2 in the same raceway 11, improving the bearing's load-carrying capacity and overall rigidity. The pin-type cage enables the bearing's load-carrying capacity to rival that of a full complement rolling element bearing, while maintaining a certain clearance between the rollers to avoid wear caused by direct contact. This better meets the load-carrying capacity requirements of gearboxes, wind power, and other fields. Here, a full complement rolling element bearing refers to a cageless bearing where the total circumferential clearance of each row of rolling elements is less than the diameter of the rolling elements and is as small as possible to improve the bearing's load-carrying capacity and operational stability.

[0065] The pin-type cage has a relatively compact and stable overall structure, which can provide a certain degree of rigid support, help improve the rotational accuracy and rigidity of the bearing, reduce the deformation of the bearing during operation, and thus make the wind turbine gearbox more stable and precise.

[0066] When subjected to impact loads, the pin 32 can absorb and buffer some of the impact energy through its own elastic deformation or by setting energy-absorbing components, thereby reducing the impact load transmitted to the cage ring 31 of the cage 3 and other components of the bearing, reducing the probability of failures such as cage breakage and cylindrical roller detachment caused by impact, and improving the bearing's impact resistance and reliability.

[0067] The diameter of the pin 32 can be smaller than the inner diameter of the center hole of the cylindrical roller 2, and a gap is left between the pin 32 and the center hole of the cylindrical roller 2. This gap is used to allow lubricating oil to enter, which can reduce the friction between the cylindrical roller 2 and the pin 32, and when installing the pin 32, this gap can facilitate the insertion of the pin 32 into the center hole of the cylindrical roller 2.

[0068] Optionally, the number of cylindrical rollers 2 and pins 32 in the same cage 3 can be the same, that is, each cylindrical roller 2 corresponds to one pin 32, so that adjacent cylindrical rollers 2 maintain a small gap, and adjacent cylindrical rollers 2 do not directly contact each other, avoiding wear. Alternatively, the number of cylindrical rollers 2 can be greater than the number of pins 32, that is, at least some of the cylindrical rollers 2 are not installed on the pins 32 and can be free from being constrained and fixed by the pins 32. The circumferential gap between the cylindrical rollers 2 can be further reduced. In this way, some of the cylindrical rollers 2 can be understood as full-compact rolling elements, so that more cylindrical rollers 2 can be set in the raceway 11, further improving the bearing's load-bearing capacity.

[0069] (Second Implementation)

[0070] The bearing assembly for a wind turbine gearbox according to the second embodiment of this application has most of the same structure as the bearing assembly for a wind turbine gearbox according to the first embodiment. The same reference numerals are used for identical or similar components in both embodiments, and specific structures will not be described again. The main differences between the bearing assembly for a wind turbine gearbox according to the second embodiment and the bearing assembly for a wind turbine gearbox according to the first embodiment include the cylindrical rollers 2 and the pins 32.

[0071] like Figures 6 to 8 As shown, a second embodiment of this application proposes a bearing assembly for a wind turbine gearbox. The bearing assembly may include a plurality of bearing units 100, and the plurality of (e.g., two) bearing units 100 may be arranged along an axial direction A.

[0072] Each bearing unit 100's cage 3 may include two cage rings 31 and multiple pins 32. The two cage rings 31 are respectively the first cage ring and the second cage ring, which are respectively disposed on opposite axial sides of the cylindrical roller 2. Two sets of pins 32 may be provided, with each set of pins 32 evenly arranged circumferentially C on the cage rings 31. One end of each pin 32 is connected to the cage ring 31, and the other end is a suspended free end. The free ends of the two sets of pins 32 are spaced apart. Here, this type of pin can be referred to as the second pin.

[0073] One set of pins 32 has its ends connected to the first cage ring, and the other set of pins 32 has its ends connected to the second cage ring. The pins 32 connected to the two cage rings 31 can be aligned, so that the two ends of the same cylindrical roller 2 can be respectively mounted on the pins 32 of the two cage rings 31.

[0074] In the same cage 3, the number of cylindrical rollers 2 can be half the number of pins 32, that is, two pins 32 are used to install and position one cylindrical roller 2 from both sides of the axial direction. Alternatively, the number of cylindrical rollers 2 can be greater than half the number of pins 32, that is, at least some of the cylindrical rollers 2 are not installed on the pins 32 and can be free from being constrained and fixed by the pins 32. The circumferential clearance between the cylindrical rollers 2 can be further reduced. In this way, some of the cylindrical rollers 2 can be understood as full-compact rolling elements, so that more cylindrical rollers 2 can be set in the raceway 11, thereby further improving the bearing's load-bearing capacity.

[0075] The cylindrical roller 2 is cylindrical with a central hole, which can be a blind hole. The pin 32 can be inserted into the central hole to mount the cylindrical roller 2 on the cage 3, and the cylindrical roller 2 can rotate around the pin 32.

[0076] In one possible implementation, the cage 3 may include a pin (through pin) connected at both ends to two cage rings respectively, and a pin (split pin) suspended at one end connected to the other end of the cage ring. The through pin can mate with a cylindrical roller with a through hole in its center, while the split pin can mate with a cylindrical roller with a blind hole or a through hole in its center. Rolling elements with through holes in their center facilitate the passage of lubricating oil, resulting in better lubrication performance of the bearing.

[0077] It is understandable that all cylindrical rollers 2 could be cylindrical rollers 2 with through holes in the center.

[0078] (Third Implementation)

[0079] The bearing assembly for a wind turbine gearbox according to the third embodiment of this application has most of the same structure as the bearing assembly for a wind turbine gearbox according to the first embodiment. The same reference numerals are used for identical or similar components in both embodiments, and specific structures will not be described again. The main difference between the bearing assembly for a wind turbine gearbox according to the third embodiment and the bearing assembly for a wind turbine gearbox according to the first embodiment includes the cylindrical roller 2.

[0080] like Figures 9 to 12 As shown, a third embodiment of this application proposes a bearing assembly for a wind turbine gearbox. The bearing assembly may include a plurality of bearing units 100, and the plurality of (e.g., two) bearing units 100 may be arranged along an axial direction A.

[0081] At least two rows of cylindrical rollers 2 can be arranged side by side along the axial direction A within the same raceway 11. The opposing end faces of the multiple cylindrical rollers 2 can abut against each other, enhancing the overall rigidity and stability of the bearing, especially resisting deformation when subjected to axial loads.

[0082] Setting multiple rows of cylindrical rollers 2 in the raceway 11 can result in a smaller length-to-diameter ratio of the cylindrical rollers 2, making machining easier and reducing production costs. Optionally, two rows of cylindrical rollers 2 can be arranged side by side along the axial direction A in the same raceway 11, and the ratio λ of the axial length Lw to the diameter Dw of the cylindrical rollers 2 (i.e., the length-to-diameter ratio Lw / Dw) can be from 3.2 to 6.5.

[0083] The axial lengths of multiple cylindrical rollers 2 can be the same or different.

[0084] When multiple cylindrical rollers 2 have the same axial length, cylindrical rollers 2 of uniform length simplify the manufacturing process, reduce the types of cylindrical rollers 2, facilitate large-scale production, and reduce costs.

[0085] When multiple cylindrical rollers 2 have different lengths, they can be staggered in the axial direction. This makes the stress level inside the bearing more uniform, and the contact wear between the cylindrical rollers 2 and the raceway 11 more uniform. Furthermore, it increases the flexibility of bearing design, allowing for flexible matching of the number of rows of cylindrical rollers 2 and the length of each row of cylindrical rollers 2 according to actual application conditions, thereby optimizing internal stress distribution and reducing production costs.

[0086] (Fourth Implementation)

[0087] The bearing assembly for a wind turbine gearbox according to the fourth embodiment of this application has most of the same structure as the bearing assembly for a wind turbine gearbox according to the third embodiment. The same reference numerals are used for identical or similar components in both embodiments, and specific structures will not be described again. The main difference between the bearing assembly for a wind turbine gearbox according to the fourth embodiment and the bearing assembly for a wind turbine gearbox according to the third embodiment includes the pin 32.

[0088] like Figures 13 to 15 As shown, the fourth embodiment of this application proposes a bearing assembly for a wind turbine gearbox. The bearing assembly may include a plurality of bearing units 100, and the plurality of (e.g., two) bearing units 100 may be arranged along an axial direction A.

[0089] Each bearing unit 100's cage 3 may include two cage rings 31 and multiple pins 32. The two cage rings 31 are a first cage ring and a second cage ring, respectively, and are respectively disposed on both axial sides of the cylindrical roller 2. Two sets of pins 32 may be provided, with each set of pins 32 evenly arranged along the circumferential direction C on the cage rings 31. One end of each pin 32 is connected to the cage ring 31, and the other end is a suspended free end. The free ends of the two sets of pins 32 are spaced apart.

[0090] Two rows of cylindrical rollers 2 can be arranged side by side along the axial direction A within the same raceway 11. The ends of one set of pins 32 are connected to the first cage ring, and the ends of the other set of pins 32 are connected to the second cage ring. The pins 32 connected to the two cage rings 31 can be aligned.

[0091] The cylindrical roller 2 is cylindrical with a central hole, which can be a blind hole. The pin 32 can be inserted into the central hole to mount the cylindrical roller 2 on the cage 3, and the cylindrical roller 2 can rotate around the pin 32.

[0092] In one possible implementation, the cage 3 may include a pin (a through-hole pin, the first pin) connected at both ends to two cage rings 31 respectively, and a pin (a split through-hole pin, the second pin) suspended at the other end of the cage ring 31. The through-hole pin can mate with a cylindrical roller with a through hole in its center, while the split through-hole pin can mate with a cylindrical roller 2 with a blind hole or a through hole in its center. A rolling element with a through hole in its center facilitates the passage of lubricating oil, resulting in better lubrication performance of the bearing. In particular, the through-hole pin can mate with more cylindrical rollers.

[0093] In one possible implementation, a bearing unit 100, or a rolling element corresponding to the same raceway, has both a first pin and a second pin. The number of first pins can be two, three, four, or more, but less than the number of second pins. The first pins can connect two cage rings 31, improving the structural stability and integrity of the cage. The connection between the second pins and the rolling elements (cylindrical rollers) or cage rings is simpler, thus combining structural stability with ease of connection.

[0094] This application is not limited to the above embodiments. Those skilled in the art can make various modifications to the above embodiments of this application under the guidance of this application, without departing from the scope of this application. In addition, the following description is provided.

[0095] In the above embodiments, each bearing unit 100 of the bearing assembly has the same structure and size, but this application is not limited to this. In other possible embodiments, the structure and axial dimensions of each bearing unit 100 of the bearing assembly may be different.

[0096] It should be understood that at least some aspects or features of the above-described implementation methods, embodiments, or examples can be appropriately combined.

[0097] It is understood that, in this application, when the number of parts or components is not specifically limited, the number can be one or more, where multiple refers to two or more. For cases where the number of parts or components shown in the drawings and / or described in the specification is, for example, two, three, four, etc., this specific number is generally exemplary and not restrictive, and can be understood as multiple, i.e., two or more; however, this does not mean that this application excludes the case of one.

[0098] In this application, unless otherwise expressly stated or limited, terms such as "installation," "assembly," "connection," "linking," "joining," "linking," "abutment," "communication," "connection," "conduction," "fixing," and "fastening" should be interpreted broadly, for example, they can be direct or indirect. For instance, regarding connection, it 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; it can be the internal communication of two components or the interaction between two components, unless otherwise expressly stated or limited. For instance, regarding communication / conduction, it can be direct communication / conduction or indirect communication / conduction through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0099] In this application, unless otherwise expressly stated or limited, a component being disposed / installed / located / enclosed / placed within, inside, or incorporated in another component can be either of the following two situations: a portion or a majority of the one component is located within the other component; or the one component is completely enclosed within the other component.

[0100] Although the present application has been described in detail using the above embodiments, it will be apparent to those skilled in the art that the present application is not limited to the embodiments described herein. The present application can be modified and implemented as alternative embodiments without departing from the spirit and scope of the present application as defined by the claims. Therefore, the description in this specification is for illustrative purposes only and does not have any limiting meaning for the present application.

Claims

1. A bearing unit for a wind turbine gearbox, characterized in that, The bearing unit includes: The bearing inner ring has an annular raceway on its outer periphery. A cage, disposed radially outside the inner ring of the bearing, the cage comprising two cage rings and a plurality of pins connected to the cage rings, the plurality of pins extending axially along the bearing unit and arranged circumferentially along the bearing unit; and A cylindrical roller rotatably connected to the cage about the pin, the cylindrical roller having a diameter of 25 to 50 mm and an axial length to diameter ratio of 3.2 to 13.

2. The bearing unit for a wind turbine gearbox according to claim 1, characterized in that, A row of cylindrical rollers is arranged in the raceway, and the ratio of the axial length to the diameter of the cylindrical rollers is 4 to 9.

3. The bearing unit for a wind turbine gearbox according to claim 1, characterized in that, At least two rows of cylindrical rollers are arranged side by side along the axial direction in the raceway, and the ratio of the axial length to the diameter of the cylindrical rollers is 3.2 to 6.

5.

4. The bearing unit for a wind turbine gearbox according to claim 1, characterized in that, The bearing unit is used to be mounted into the inner bore of the planetary gear, and the cylindrical rollers are used to make direct rolling contact with the inner circumferential surface of the planetary gear. The bearing unit does not include the outer bearing ring.

5. The bearing unit for a wind turbine gearbox according to claim 1, characterized in that, The two ends of the pin are respectively connected to the two cage rings. The center hole of the cylindrical roller is a through hole. The pin passes through the cylindrical roller so that the cylindrical roller is sleeved on the pin.

6. The bearing unit for a wind turbine gearbox according to claim 2, characterized in that, In the same cage, the number of cylindrical rollers and pins are the same, or the number of cylindrical rollers is greater than the number of pins, and at least some of the cylindrical rollers are not mounted on the pins.

7. The bearing unit for a wind turbine gearbox according to claim 1, characterized in that, One end of the pin is connected to the cage ring, and the other end of the pin is a suspended free end. The pin is inserted into the center hole of the cylindrical roller.

8. The bearing unit for a wind turbine gearbox according to claim 7, characterized in that, The center hole of the cylindrical roller is a blind hole, or The central hole of the cylindrical roller is a through hole, or The center hole of one part of the cylindrical rollers is a blind hole, while the center hole of the other part of the cylindrical rollers is a through hole.

9. The bearing unit for a wind turbine gearbox according to claim 2, characterized in that, In the same cage, the number of cylindrical rollers is half the number of pins, or the number of cylindrical rollers is greater than half the number of pins, and at least some of the cylindrical rollers are not mounted on the pins.

10. The bearing unit for a wind turbine gearbox according to claim 1, characterized in that, The diameter of the pin is smaller than the inner diameter of the center hole of the cylindrical roller, and a gap is left between the pin and the center hole of the cylindrical roller.

11. The bearing unit for a wind turbine gearbox according to claim 1, characterized in that, The pin includes: The first pins at both ends are respectively connected to the cage ring; and A second pin, one end of which is connected to the cage ring and the other end of which is a suspended free end, The number of the first pins is two or more, and the number of the first pins is less than the number of the second pins.

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