The present invention is directed to a wind turbine bearing seal, and more particularly to a floating wind turbine bearing seal having an enhanced profile for sealing the space between wind turbine bearings.
Wind turbines employ bearing structures to control the pitch and yaw of a wind turbine. Conventionally, a yaw bearing permits the turbine blades to turn toward the wind, and a pitch bearing can control the angle of the blades to optimize the force of the incoming wind to turn the blades.
A conventional wind turbine bearing assembly typically is of a type of bearing assembly referred to in art as a “slewing bearing” or “slewing ring bearing”. Such bearing assemblies generally include two concentric ring structures, commonly referred to in the art as “races”. The races define or form a track or recess therebetween, into which a plurality of ball bearings, roller bearings, or similar bearing components may be placed. In such an assembly, with ball or roller bearings in a track formed by two concentric races, the races may rotate relative to one another. It will be appreciated that wind turbine bearing assemblies are quite large, with the races tending to have a diameter of approximately eight to ten feet or more. With structures of such size, which often are made of metal components, wear of the bearing structures needs to be minimized.
The configuration of a slewing ring bearing has a high load carrying capacity, and thus can be utilized in a versatile range of applications, including wind turbines. Due to their design, a slewing ring bearing can reliably support radial, axial and tilting moment loads. It is therefore possible in many cases to replace bearing arrangements including a combination of radial and axial bearings by a single bearing. This reduces the costs and work required in the design of the adjacent structures and the fitting of bearings in a variety of applications, including wind turbines.
To minimize friction as between the relative movements of the ball bearings and races, a lubricating material, such as a lubricating grease, is provided within the track and adjacent surfaces so as to coat the races and ball bearings in areas where they contact. The lubricating material or grease increases the freedom of movement of the bearing structures, which reduces friction and wear. Typically, however, adjacent top and bottom surfaces of the races where they come together, a small space between the two races tends to be present outward from the ball bearings in both directions perpendicularly to the track. The lubricating material or grease, therefore, would leak out from the area of the track and ball bearings unless the space between the races is sealed.
To prevent leakage of the lubricating material or grease, a bearing seal may be provided between the races and in the area of the referenced space between them. Bearing seals also prevent contamination of internal bearing components by external environmental contaminants. Conventional configurations of wind turbine bearing seals, however, have proven deficient. In such conventional configurations, the bearing seal is attached to one or the other of the races. A significant internal torque is generated of the unattached race against the bearing seal. As the races move relative to one another, therefore, the unattached race causes significant wearing of the bearing seal. Wind turbine bearing seals, therefore, typically are subject to intense wear and must be replaced often. A worn seal increases the propensity for leakage of the lubricating material or grease. In addition, once a significant portion of the lubricating material leaks, wearing of the ball bearings and races can reduce the efficiency of the wind turbine, and a severe case of wear can result in damage and failure of the wind turbine components.
The present invention provides an enhanced bearing seal assembly that is less subject to wear as compared to conventional configurations. In exemplary embodiments, a bearing seal assembly is provided for sealing a sealing gap defined by a first race and a second race of a bearing. The bearing seal assembly includes a resilient seal having a cross-sectional profile, wherein the profile defines a flexing portion, and the resilient seal further has a first pressure-bearing side and a second side opposite the first pressure-bearing side. The flexing portion is configured to flex to form an energized seal that seals the sealing gap when a pressure is applied to the first side of the resilient seal, wherein the cross-sectional profile is symmetric about a horizontal axis and asymmetric about a vertical axis. The cross-sectional profile specifically may be a K-shaped profile, and the flexing portion comprises arms defined by the K-shaped profile.
Another aspect of the invention is a bearing assembly including a first race and a second race that define a sealing gap, and the bearing seal assembly that seals the sealing gap.
The bearing seal assembly may include a wear strip section positioned outside of the profile of the resilient seal. The wear strip section may include a first wear strip portion located outside one side of the profile, and a second wear strip portion located outside of the profile oppositely to the first wear strip portion. The wear strip section further may include a removable blast shield that prevents contamination of the bearing seal assembly during installation. Prior to removal, the blast shield connects the first wear strip portion to the second wear strip portion, and removal of the blast shield separates the first wear strip portion from the second wear strip portion.
Another aspect of the invention is a method of assembling a bearing seal assembly. In exemplary embodiments, the method may include the steps of: providing a bearing seal; positioning the bearing seal within a wear strip section having a blast shield to form a seal assembly; compressing the seal assembly with a compressive force; providing a bearing assembly including a first race and a second race that define a sealing gap; inserting the seal assembly into the sealing gap of the bearing assembly; releasing the compressive force; and removing the blast shield. The method further may include subjecting the bearing seal assembly to a coating process prior to removing the blast shield.
These and further features of the present invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the invention may be employed, but it is understood that the invention is not limited correspondingly in scope. Rather, the invention includes all changes, modifications and equivalents coming within the spirit and terms of the claims appended hereto. Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.
Embodiments of the present invention will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be understood that the figures are not necessarily to scale.
The present invention provides an improved bearing seal and seal assembly for use in a wind turbine bearing. The wind turbine bearing seal and seal assembly of the present invention reduce wear as compared to conventional configurations, while maintaining an effective seal against high-pressure leakage of the lubricating material or grease and against external environmental contaminants.
In accordance with such features, an aspect of the invention is a bearing seal assembly for sealing a sealing gap defined by a first race and a second race of a bearing. Embodiments of the bearing seal assembly may include a resilient seal having a cross-sectional profile. The profile defines a flexing portion, and the resilient seal further has a first pressure-bearing side and a second side opposite the first pressure-bearing side. The flexing portion is configured to flex to form an energized seal that seals the sealing gap when a pressure is applied to the first pressure-bearing side of the resilient seal. The cross-sectional profile may be symmetric about the horizontal axis and asymmetric about the vertical axis, and may be a K-shaped profile in particular. Embodiments of the bearing seal assembly may also include a wear strip section positioned outside of the profile of the resilient seal.
The races and ball or roller bearings may be made of metal and/or metal alloys that are sufficiently strong to support movement of the wind turbine blades. Titanium, steel, aluminum, or other metals, or combinations thereof, may be employed as are known in the art. The ball or roller bearings 20 can spin within the track 18, which permits the races 10 and 12 to rotate about a center axis of the bearing assembly in opposite directions relative to each other and in concentric fashion.
To minimize friction as between the movements of the ball/roller bearings and races, a lubricating material, such as a high performance lubricating grease, is provided within the track 18 and adjacent surfaces so as to coat the races 10/12 and ball bearings 20 in areas where they contact. The lubricating material may be a petroleum based grease or gell, or any comparable lubricants as are known in the art for reducing friction as between moving parts, and moving metal parts in particular. The lubricating material or grease increases the freedom of movement of the bearing structures, which reduces friction and wear. Typically, however, on both sides of the ball bearings in a direction perpendicularly to the track 18, small spaces 22 are present between the two races. The lubricating material or grease, therefore, would leak out from the area of the track 18 unless the spaces 22 between the races are sealed on both sides of the ball bearings.
To prevent leakage of the lubricating material or grease, a resilient bearing seal 24 may be provided between races 10 and 12 within a sealing gap 26 defined by the races at locations outward from the ball bearings 20 in a direction perpendicularly to the track 18. The bearing seal 24 and commensurate sealing gap 26 extend concentrically between the races over the full 360 degrees of the complete slewing ring bearing 100. The resilient bearing seal 24 may be made of a resilient polymer material, rubber or rubber-like material, plastics, thermoplastics, and/or other resilient and flexible materials and combinations thereof as are known in the art to be used for seals. Essentially, any material suitable for a wind turbine bearing seal may be employed to form the bearing seal 24.
Although the present invention is described principally in connection with a bearing assembly formed of concentric races as depicted in
The outer race 10 has a first inside surface 28, and the inner race 12 has a second inside surface 30. The two inside surfaces define the sealing gap 26 and space 22 between the races. As represented by the patterning in
It will be appreciated that in the absence of the bearing seal 24, the lubricating material 32 would simply leak out of the bearing assembly from the sealing gap 26, through an additional outer gap 34 defined by the races, and then to the outside. The bearing seal 24 effectively prevents any significant leakage of the lubricating material through the outer gap 34. The bearing seal 24 also prevents contamination of internal bearing components by external environmental contaminants.
To aid in positioning the bearing seal 24 within the sealing gap 26, the outer race 10 includes an outer race ridge 40, and the inner race 12 includes an inner race ridge 42. The outer and inner race ridges 40/42 maintain the bearing seal 24 within the sealing gap 26. In part because of the race ridges, the bearing seal 24 need not be attached to or fixed to either of the outer (first) or inner (second) races 10 or 12. Rather, the bearing seal rests unattached or “floats” within the sealing gap 26. The bearing seal 24, therefore, is referred to a “floating seal”. A floating bearing seal of the present invention differs from the conventional bearing seal that is fixed to one or other of the races. Because the bearing seal 24 floats in the sealing gap 26, as the races rotate around the seal, the internal torque is diminished as compared to a configuration in which the seal is attached to or fixed to one of the races. As stated above, the unattached race generates a torque as to the fixed bearing seal, which can increase the wearing of the seal, particularly at the initiation of the movement of the races. Because the bearing seal of the present invention floats, this additional torque between a race and the bearing seal is effectively reduced. The configuration of the present invention, therefore, reduces wear as compared to the conventional configurations by reducing the internal torque that results from conventional fixed bearing seals.
As stated above, the bearing seal 24 extends concentrically between the outer race 10 and the inner race 12. As further seen in
As the races of the wind turbine bearing rotate relative to each other, outward pressure of the lubricating material tends to increase substantially within the sealing gap 26. This increased pressure can force the various arms of the bearing seal profile against one or more of the race inside surfaces 28 and 30 at various points. In particular, the cross-sectional profile 58 defines a flexing portion that is configured to flex to form an energized seal that seals the sealing gap. The seal has a first pressure-bearing side and a second side opposite the first side. The first pressure-bearing side may be defined by the two lower arms 58c and 58d, and the second side may be defined by the two opposite arms 58a and 58b of the K-shaped profile. The profile defines a flexing portion in that the arms flex when the increased pressure within the bearing seal assembly is applied to the first pressure-bearing side of the seal. The arms 58c and 58d that define the first pressure-bearing side in particular tend to flex upon an increase in the pressure. In this manner, the flexing portion is configured to flex to form an energized seal that seals the sealing gap when a pressure is applied to the first side of the resilient seal.
The K-shaped profile, therefore, has an advantage in that the arms may flex in response to the increased pressure within the bearing seal assembly. Coupled with the floating configuration described above, the K-shaped profile and the floating configuration substantially reduce the wear of the bearing seal. The seal of the present invention, therefore, lasts longer and provides an enhanced seal as compared to conventional configurations while maintaining an effective seal under increased pressure of the lubricating material.
The embodiment of
The wear strip portions may be made of materials comparable to the materials used to make the bearing seal 24. Such materials, for example, may include a resilient polymer material, rubber or rubber-like materials, plastics, thermoplastics, epoxies, and/or other resilient and flexible materials and combinations thereof as are known in the art to be used for seals. The wear strip portions 60 and 62 further reduce friction as between the bearing seal 24 and the races 10/12, thereby enhancing the floating seal characteristics of the bearing seal. Similarly to the embodiment of
The present invention obviates the need in the conventional configuration to utilize a first bearing seal during coating, which then is removed and replaced with a second bearing seal for actual use. Rather, in the present invention only one bearing seal is required.
The bearing seal assembly 64 may be formed by a variety of processes that would result in the bearing seal 24 being inside the wear strip section 66. For example, to form the bearing seal assembly the bearing seal and the wear strip section 66 may be molded together, or separately formed with the bearing seal being subsequently inserted or installed into the wear strip section to locate the wear strip section outside of the profile of the bearing seal such that the bearing seal is within the wear strip section.
As seen in
In the configuration of
While in the second uncompressed state, the blast shield is removable, and removal of the blast shield separates the first wear strip portion 70 from the second wear strip portion 72. As stated above, to permit the flexing of the blast shield components, the wear strip section 66 may be notched or otherwise weakened at the flexing points 80a-c as compared to the remainder of the wear strip section. After a coating process is completed, the blast shield 74 may be removed from the remainder of the wear strip section 66. For example, the blast shield may be torn or stripped away at the flexing points 80a and 80c from the remainder of the wear strip section 66. In this manner, flexing portions 80a and 80c in particular permit the blast shield 74 to be effectively “unzipped” from the remainder of the wear strip section 66.
The resultant configuration is that of
In accordance with the above,
The method may begin at step 120, in which a bearing seal, such as the bearing seal 24, is provided. At step 130, the bearing seal may be positioned within a wear strip section having a blast shield, such as the wear strip section 66 having the blast shield 74, to form a seal assembly such as the seal assembly 64. It will be appreciated that both the timing and manner of steps 120 and 130 may be varied and/or combined. For example, as stated above, to form the seal assembly the bearing seal and the wear strip section may be molded together, or formed separately with the bearing seal subsequently being inserted or installed into the wear strip section to locate the bearing seal within the wear strip section.
At step 140, the seal assembly may be compressed in the horizontal direction with a compressive force, such as, for example, depicted in
The bearing seal and associated structures described in this disclosure have advantages over conventional configurations. The described bearing seal is provided in a floating configuration and has a profile that is asymmetric about the vertical axis and symmetric about the horizontal axes, and may have a K-shaped profile in particular. The floating configuration combined with a symmetrical profile substantially reduces internal torque generated by the bearing assembly during use. The reduced internal torque results in a substantial reduction of seal wear, which prolongs the life of the seal while precluding leakage of the lubricating material. The use of a wear strip section further reduces such internal torque. The additional blast shield of the wear strip section also protects the bearing seal and other internal bearing components during a coating process. There is no need, therefore, to employ one bearing seal during coating, and then replacing this first bearing seal with a second bearing seal for actual use. The described bearing seal, therefore, is simpler and more efficient to assemble and install as compared to conventional configurations.
An aspect of the invention, therefore, is a bearing seal assembly for sealing a sealing gap defined by a first race and a second race of a bearing. In exemplary embodiments, the bearing seal assembly includes a resilient seal having a cross-sectional profile, wherein the profile defines a flexing portion, and the resilient seal further has a first pressure-bearing side and a second side opposite the first pressure-bearing side. The flexing portion is configured to flex to form an energized seal that seals the sealing gap when a pressure is applied to the first side of the resilient seal, and wherein the cross-sectional profile is symmetric about a horizontal axis and asymmetric about a vertical axis. The bearing seal assembly may include one or more of the following features either individually or in combination.
In an exemplary embodiment of the bearing seal assembly, the cross-sectional profile is a K-shaped profile, and the flexing portion comprises arms defined by the K-shaped profile.
In an exemplary embodiment of the bearing seal assembly, the first pressure -bearing side is defined by two of the arms of the K-shaped profile, and the second side is defined by two opposite arms of the K-shaped profile.
In an exemplary embodiment of the bearing seal assembly, the bearing seal assembly further includes a wear strip section positioned outside of the profile of the resilient seal.
In an exemplary embodiment of the bearing seal assembly, the wear strip section comprises a first wear strip portion located outside one side of the profile, and a second wear strip portion located outside of the profile oppositely to the first wear strip portion.
In an exemplary embodiment of the bearing seal assembly, the wear strip section further comprises a removable blast shield that prior to removal, connects the first wear strip portion to the second wear strip portion, and removal of the blast shield separates the first wear strip portion from the second wear strip portion.
In an exemplary embodiment of the bearing seal assembly, the blast shield comprises a first segment and a second segment, and the bearing seal assembly is compressible with a compressive force. In a first compressed state of the bearing seal assembly, the first and second segments of the blast shield are oriented in an angular configuration, and in a second uncompressed state of the bearing seal assembly, the first and second segments of the blast shield are linearly aligned. In the first compressed state the bearing seal assembly is insertable into the sealing gap, and upon release of the compressive force, the bearing seal assembly reconfigures to the second uncompressed state to seal the sealing gap.
In an exemplary embodiment of the bearing seal assembly, the blast shield is removable when the bearing seal assembly is in the second uncompressed state.
Another aspect of the invention is a bearing assembly including a first race and a second race that define a sealing gap, and the bearing seal assembly that seals the sealing gap. The bearing assembly may include one or more of the following features either individually or in combination.
In an exemplary embodiment of the bearing assembly, the first race and the second race are concentric races and define a track that is in fluid communication with the sealing gap. The bearing assembly further includes a plurality of ball bearings or roller bearings located within the track that permit the first race to rotate concentrically and in an opposite direction relative to the second race, and a lubricating material for lubricating the ball or roller bearings and the races. The bearing seal assembly is configured to seal the bearing assembly to prevent leakage of the lubricating material from the sealing gap.
In an exemplary embodiment of the bearing assembly, the first race and the second race are stacked in the axial direction and define a track that is in fluid communication with the sealing gap. The bearing assembly further includes a plurality of ball bearings or roller bearings located within the track that permit the first race to rotate in an opposite direction relative to the second race, and a lubricating material for lubricating the ball or roller bearings and the races. The bearing seal assembly is configured to seal the bearing assembly to prevent leakage of the lubricating material from the sealing gap.
In an exemplary embodiment of the bearing assembly, the bearing seal assembly is a floating seal assembly that is not attached to either of the first race or the second race.
In an exemplary embodiment of the bearing assembly, the bearing seal assembly includes a wear strip, wherein at least a portion of the wear strip section is attached to one of the races, and the bearing seal is a floating seal that is not attached to either of the first race, the second race, or the wear strip section.
In an exemplary embodiment of the bearing assembly, resilient seal is energized when a pressure of the lubricating material is applied to the first pressure-bearing side of the resilient seal.
In an exemplary embodiment of the bearing assembly, the bearing assembly is a wind turbine bearing assembly.
Another aspect of the invention is a method of assembling a bearing seal assembly. In exemplary embodiments, the method may include the steps of: providing a bearing seal; positioning the bearing seal within a wear strip section having a blast shield to form a seal assembly; compressing the seal assembly with a compressive force; providing a bearing assembly including a first race and a second race that define a sealing gap; inserting the seal assembly into the sealing gap of the bearing assembly; releasing the compressive force; and removing the blast shield. The method further may include subjecting the bearing seal assembly to a coating process prior to removing the blast shield.
Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
This application claims the benefit of U.S. Provisional Application No. 62/081,685 filed Nov. 19, 2014, which is incorporated herein by reference.
Number | Date | Country | |
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62081685 | Nov 2014 | US |