Abstract
Provided is a seal for a bearing arrangement for sealing an interior space between at least two parts of the bearing arrangement rotatable relatively to each other, and in which the interior space contains a lubricant, whereby the seal includes a seal part which is shaped for conveying the lubricant with a direction component pointing into the interior space.
Claims
1. A seal for a bearing arrangement for sealing an interior space between at least two parts of the bearing arrangement rotatable relatively to each other, in which the interior space contains a lubricant, wherein the seal comprises a seal part which is shaped for conveying the lubricant with a direction component pointing into the interior space.
2. The seal according to claim 1, wherein the seal part comprises an edge with a lubricant-guiding edge profile, which is a periodically repeated pattern.
3. The seal according to claim 2, wherein the periodically repeated pattern is one of a saw-tooth profile, a pattern consisting of spaced triangles, a sinusoidal profile, and a superposition thereof.
4. The seal according to claim 1, wherein the seal part is one-piece or consists of two or more segments which are connectable to each other.
5. The seal according to claim 1, wherein the seal comprises a seal body connected to the seal part.
6. The seal according to claim 5, wherein the seal body is glued to the seal part.
7. The seal according to claim 5, wherein the edge of the seal part protrudes the seal body.
8. The seal according to claim 5, wherein the seal body consists of an elastic and compressible material.
9. The seal according to claim 8, wherein the seal body consists of one of rubber, cellular rubber, and foamed polymer.
10. The seal according to claim 1, wherein the seal part consists of a polymer material.
11. A wind turbine comprising at least one rotor and at least one stationary structure, in which the rotor and the stationary structure are connected by a bearing, wherein the bearing comprises a seal according to claim 1.
12. The seal according to claim 10, wherein the seal part consists of PTFE.
Description
BRIEF DESCRIPTION
[0018] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:
[0019] FIG. 1 shows a sectional side view of a bearing arrangement of a wind turbine comprising a seal according to embodiments of the invention;
[0020] FIG. 2 shows a top view of an embodiment of a seal according to embodiments of the invention;
[0021] FIG. 3 shows a top view of an alternative embodiment of a seal according to embodiments of the invention;
[0022] FIG. 4 shows a top view of another alternative embodiment of a seal according to embodiments of the invention;
[0023] FIG. 5 shows a top view of another alternative embodiment of a seal according to embodiments of the invention;
[0024] FIG. 6 shows a cut side view of an embodiment of a seal according to embodiments of the invention;
[0025] FIG. 7 shows a perspective view of a seal according to embodiments of the invention; and
[0026] FIG. 8 shows a top view of a seal segment according to embodiments of the invention.
DETAILED DESCRIPTION
[0027] In FIG. 1, a sectional view of a bearing arrangement 21 is shown, in which the bearing arrangement 21 comprises an embodiment of a seal 1 consisting of a seal body 2 and a seal part 3. The bearing arrangement 21 incorporates a rotatable outer ring 4 and a stationary inner ring 5 rotatably mounted by roller 6. The outer ring 4, the inner ring 5, and the roller 6 surround an interior space 22 containing a lubricant like for instance grease. The seal 1 is fixed in between the outer ring 4 and the plate 7 by compression of the seal body 2. The plate 7 is fixed to the outer ring 4 by a screw 8. The seal part 3 of the seal 1 comprises a lubricant-guiding edge profile 9 oriented towards the interior space 22. The depicted bearing arrangement is rotationally symmetric with the outer ring 4, plate 7, screw 8, and seal 1 rotating around the inner ring 5 and the roller 6. This rotational movement of the seal 1, in particular the movement of the lubricant guiding edge profile 9 composed by the seal part 3 causes a conveying of the grease towards the interior space 22.
[0028] FIG. 2 shows a top view on a first embodiment of a seal 1. The seal 1 comprises a seal body 2 and a seal part 3. In this embodiment, the lubricant guiding edge profile 9 is a saw-tooth profile, which is formed by a periodical repetition of right-angled triangles 15. Each of the right-angled triangles 15 comprises a tip angle 10, an edge in forward direction 11, and an edge in backward direction 12. Forward and backward direction refer to the movement direction of the seal 1. For an application in a wind turbine, a range for the tip angle is 15 to 45, the range of the dimension of the edge in forward direction is between 5 mm and 30 mm and for the edge in backward direction between 2 mm to 10 mm. The seal body 2 has a thickness in between 20 mm and 40 mm and a height extending in the plane of projection of also 20 mm to 40 mm and consists of an elastic and compressible material, rubber, cellular rubber or foamed polymer. The seal part consists of a polymer material, PTFE and has a thickness in the plane of projection between 1 mm and 3 mm. The usage of PTFE for the seal part 3 causes in an arrangement like shown in FIG. 1 low friction between the seal part 3 and the inner ring 5 during operation of the bearing arrangement 21. The seal 1 is installed in such way, that there is no gap or only a small gap between seal part 3 and the inner ring 5. Grease or other lubricant that comes in contact with an edge in forward direction 11 of the depicted saw-tooth profile is shifted towards the interior space 22 of the bearing arrangement 21. While moving constantly during operation, the seal 1 constantly conveys grease or other lubricant, which is going to leak from the bearing, back towards the interior space 22 and minimizes therefore the amount of leaked lubricant. The entire saw-tooth profile of the lubricant-guiding edge profile 9 is protruding the seal body 2, so that the tips in forward direction of the right-angled triangles 15 are not covered by the seal body 2.
[0029] Alternative embodiments of the invention are depicted in FIG. 3. The seal 1 consists of a seal body 2 and a seal part 3 exhibiting a lubricant guiding edge profile 9 consisting of separated triangles 13. In this embodiment, the triangles 13 of the lubricant-guiding edge profile 9 are separated by intermediate sections 14. The lubricant guiding functionality of the seal part is obtained only by the edges of the triangles 13 that point towards the interior space of the bearing and not by the intermediate sections 14. As the triangles 13 of this embodiment are isosceles triangles, the lubricant guiding functionality of the seal 1 is provided in both directions of circumferential rotational movement. Alternatively, the edge profile 9 can contain also other types of triangles or other geometric shapes that are repeated periodically either with the intermediate sections 14 or without.
[0030] Further embodiments of the invention are shown in FIG. 4 where a seal 1 consisting of a seal body 2 and a seal part 3 exhibit a sinusoidal lubricant-guiding edge profile 9. The sinusoidal edge profile also enables a lubricant guiding functionality in both rotational directions. In this case, the lubricant is guided by the forward direction side of the sinusoidal wave form.
[0031] Further embodiments with a superposition of triangular and sinusoidal patterns is shown in FIG. 5. The pattern obtained from the superposition exhibits periodically repeated geometric shapes, which form edges dedicated as edges in forward direction 11 which are differently than the edges in backward direction 12. As depending on the superimposed patterns, a wide variety of lubricant guiding edge profiles can be obtained for lubricant guidance in both one direction and two directions by superposition. In all depicted embodiments, the lubricant-guiding edge profile 9 of the seal part 3 is protruding the seal body 2 in such way that the entire lubricant guiding edge profile 9 is not covered by the seal body 2.
[0032] In FIG. 6, a seal part segment 16 is shown exhibiting a flute 17 and a notch 18 as counterpart for a dovetail joint. Also, the segmented seal body 2 exhibits a flute 23 and a notch 24 for establishing a positive connection. The seal part of a seal can be one-piece, so that the ring structure is obtained by connecting the flute 17 to the notch 18 of the same seal part segment. Alternatively, two or more seal part segments 16 can be connected to each other to form a ring like it is depicted in FIG. 7. Thereby, the lubricant-guiding edge profile 9 of each seal part segment is formed in such way, that the connected seal part segments exhibit in total an edge profile with a constant periodicity. In FIG. 7, the seal body 2 is one-piece and has been attached, for instance by gluing, to the connected seal part segments 16.
[0033] A sectional view of an unmounted seal 1 is depicted in FIG. 8. The seal part 3 made of PTFE is glued to the seal body 2 made for instance of cellular rubber and can be one piece or consists of separate parts which are for instance glued together or otherwise permanently fixed. The upper part 20 of the seal body can protrude the lower part 19 on either side and the range of the protrudance is between 2.5 mm and 7.5 mm. The seal 1 is mounted in the bearing by compression of the upper part 20 between for instance the outer ring 4 and the plate 7 like it is shown in FIG. 1. Due to this compression, the relative movement between the outer ring 4 and the seal 1 is prevented and the seal 1 is fixed in its mounted state.
[0034] Although the invention has been illustrated and described in greater detail with reference to the preferred exemplary embodiment, the invention is not limited to the examples disclosed, and further variations can be inferred by a person skilled in the art, without departing from the scope of protection of the invention.
[0035] For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.
