Assembly for sealing off a pitch tube

Abstract

Proposed is a seal assembly (101, 201, 301) for a pitch tube (103) of a wind turbine gearbox. The seal assembly (101, 201, 301) has at least one axial shaft sealing ring (111) and at least one circular-ring-shaped counterpart running surface that is rotatable relative to the axial shaft sealing ring (111), wherein the pitch tube (103), the axial shaft sealing ring (111) and the counterpart running surface are oriented coaxially with respect to one another, and wherein at least one sealing lip of the axial shaft sealing ring (111) is braced axially against the counterpart running surface.

Description

[0001] Arrangement for sealing a pitch pipe

[0002] The invention relates to a sealing arrangement according to the preamble of claim 1.

[0003] WO 2021 / 083466 A1 discloses a sealing arrangement for a pitch tube of a wind turbine gearbox. A labyrinth seal is used to seal the pitch tube, the labyrinth of which encloses an outer surface of the pitch tube. The pitch tube is rotatable relative to the labyrinth seal and is supported by a bearing in the labyrinth seal.

[0004] The bearing is required to ensure a consistent clearance between the pitch tube and the seal. Otherwise, the pitch tube would collide with the seal due to tolerance-related radial bearing deviations.

[0005] The bearing can generally be lubricated with oil or grease. A grease-lubricated bearing has the disadvantage of a limited service life of the grease filling. An oil-lubricated bearing requires additional lines to supply the bearing with oil.

[0006] The invention is based on the object of improving the mounting and sealing of a pitch tube of a wind turbine gearbox. This object is achieved by a sealing arrangement for a pitch tube of a wind turbine gearbox according to claim 1. Preferred developments are contained in the subclaims and will become apparent from the following description.

[0007] A wind turbine gearbox is a gearbox designed for use in the drive train of a wind turbine. In addition to the gearbox, the drive train includes a wind-driven rotor and a generator. The gearbox is located between the rotor and the generator and transmits the rotor's drive torque to the generator. A pitch tube is a feed-through tube for routing supply lines, such as electrical or hydraulic ones, through the gearbox. It runs through the gearbox or the gearbox housing. Accordingly, the openings of the pitch tube are located outside the gearbox or the housing. The pitch tube is preferably sealed against the housing so that it is impermeable to lubricant.

[0008] According to the invention, the sealing arrangement comprises at least one axial shaft seal. This is a shaft seal that seals a gap extending in the axial direction, i.e., in the direction of a rotational and / or central axis of the pitch tube, between two relatively rotatable transmission components.

[0009] The sealing arrangement also includes at least one annular counter-running surface. The counter-running surface is thus in the shape of a circular ring. An annulus is a surface between two concentric circles, i.e., between two circles with a common center point that extend in a common plane.

[0010] In this case, the counter-running surface is rotatable relative to the axial shaft seal. In particular, a first of the two aforementioned relatively rotatable transmission components, between which the gap to be sealed extends, can have the surface, wherein the axial shaft seal is part of the second transmission component or is fixed in the second transmission component.

[0011] The pitch tube, the axial shaft seal, and the counterface are aligned coaxially. Thus, a center axis of the pitch tube, a center axis of the axial shaft seal, and a center axis of the counterface coincide.

[0012] The axial shaft seal is designed as a lip seal. This means that it has at least one sealing lip. The sealing lip is clamped against the mating surface. This means that the sealing lip rests against the mating surface along a circular or annular contact surface and exerts a clamping force on the mating surface via the contact surface. The axial shaft seal is clamped axially against the mating surface with its sealing lip. Accordingly, the clamping force is axial, i.e., parallel to the aforementioned center axes.

[0013] The sealing arrangement according to the invention enables an axially offset arrangement of the axial shaft seal and the counter-running surface. Radial movements of the axial shaft seal and the counter-running surface relative to one another due to tolerance-related radial positional deviations of the pitch tube therefore do not lead to a collision of the axial shaft seal with the counter-running surface. Rather, the axial distance between the axial shaft seal and the counter-running surface remains constant. This eliminates the need for bearings for the pitch tube in the area of ​​the sealing arrangement. Likewise, there is no need for lubricant lines specifically designed for bearings. If the pitch tube is not supported in the area of ​​the sealing arrangement and is thus free-floating, there is no risk of bearing damage.

[0014] In a preferred embodiment, the axial shaft seal is fixed in a rotationally fixed manner relative to the pitch tube. Since the counter-running surface is rotatable relative to the axial shaft seal, this implies that the counter-running surface and, accordingly, the aforementioned second transmission component are rotatable relative to the pitch tube.

[0015] The arrangement is preferably further developed with a web that runs around the pitch tube. The web is preferably rotationally symmetrical to the aforementioned central axes. It has the counter-running surface. This implies that the web is part of the aforementioned second gear component. Starting from a base body of the second gear component, the web preferably extends radially inward, i.e., in the direction of the aforementioned central axes.

[0016] The axial shaft seal can be fixed directly to the pitch tube. In this case, the pitch tube is identical to the aforementioned first transmission component. In a preferred embodiment, however, the first transmission component is a means that is designed separately from the pitch tube, in particular is not integrally connected to the pitch tube. The means is designed to be fixed in several axial positions, i.e., in at least two axial positions, on an outer surface of the pitch tube. Preferably, the means can be fixed in at least three, at least four, at least five, at least ten, at least twenty, or any number of axial positions on the outer surface of the pitch tube.

[0017] Preferably, the means is fixed to the pitch tube in a fixed manner, i.e., without the possibility of relative movement. In the unfixed state, the means is preferably axially displaceable on the outer surface of the pitch tube. In a position that the means can assume within the scope of its displaceability on the outer surface of the pitch tube, it can then be fixed to the outer surface of the pitch tube.

[0018] The ability of the means to be fixed in several axial positions according to the further development is advantageous because it enables precise positioning of the means and thus of the axial shaft seal relative to the counter-running surface, independent of tolerance-related length deviations of the pitch tube.

[0019] The means is preferably further developed with a recess. This recess runs in the circumferential direction and thus around a central axis of the means. If the means is fixed to the pitch tube, the recess thus runs around the pitch tube and around the central and / or rotational axis of the pitch tube.

[0020] The course of the recess is preferably self-contained. A beginning from which the means runs around its central axis therefore corresponds to the end of this course. In particular, the recess can be rotationally symmetrical to the central axis of the means and thus also to the central and / or rotational axis of the pitch tube. In the axial direction, the recess extends so far that it projects beyond the web on both the rotor and generator sides. The recess therefore extends further in the axial direction than the web on both the rotor and generator sides. The web is thus axially aligned in such a way that in the event of a radial positional deviation of the pitch tube, it can plunge into the recess without touching the center. This prevents damage to the means and the web even in the event of larger positional deviations.

[0021] As an alternative to the axial shaft seal, in a preferred embodiment, the counter surface can be fixed in a rotationally fixed manner relative to the pitch tube. In this case, the axial shaft seal, which is rotatable relative to the counter running surface, is rotatable relative to the pitch tube. In this case, too, a web having the counter running surface preferably extends around the pitch tube, as described above. In contrast to the above embodiments, however, the web is also fixed in a rotationally fixed manner relative to the pitch tube when the counter running surface is fixed in a rotationally fixed manner relative to the pitch tube.

[0022] Furthermore, the arrangement is preferably further developed with a means that, as described above, can be fixed in several axial positions on the outer surface of the pitch tube. According to the further development, however, the means does not comprise the axial shaft seal, but rather the counter-running surface.

[0023] In a preferred embodiment, the means described above, which comprises the axial shaft seal or the counter-running surface, is non-positively fixed to a cylindrical section of the outer surface of the pitch tube. Specifically, the outer surface of the pitch tube is at least partially circular-cylindrical. At least a portion of the outer surface of the pitch tube thus has the shape of a circular cylinder. The means is non-positively fixed to this surface.

[0024] The force-fit connection is preferably achieved through a compressive stress that the means applies to the circular cylindrical section of the outer surface. To apply the compressive stress, the means can, for example, have a clamping mechanism. Alternatively, the means can be secured by an interference fit, which can be achieved, for example, by shrinking the means onto the circular cylindrical section of the outer surface and / or by expanding the pitch tube in the area of ​​the circular cylindrical section.

[0025] The advanced force-locking fixation of the means allows the axial position of the means to be freely selected within the circular cylindrical section. The set of possible axial positions of the means thus corresponds to an open or closed interval of real numbers.

[0026] In a preferred development, the arrangement comprises, in addition to the above-described first-mentioned axial shaft seal and the above-described first-mentioned counter-running surface, a further axial shaft seal and a further counter-running surface. The further axial shaft seal is arranged mirror-symmetrically to the first-mentioned axial shaft seal. Likewise, the further counter-running surface is arranged mirror-symmetrically to the first-mentioned counter-running surface. A mirror plane of the axial shaft seals and a mirror plane of the counter-running surfaces are identical. The mirror plane is preferably oriented radially, i.e., orthogonally to the above-mentioned axis of rotation and the above-mentioned central axes.

[0027] Similar to the first axial shaft seal and the first counter-running surface, the second counter-running surface is rotatable relative to the second axial shaft seal. The pitch tube, the second axial shaft seal, and the second counter-running surface are aligned coaxially with each other according to the further development. Like the first axial shaft seal, the second axial shaft seal also has at least one sealing lip. This lip is clamped axially against the second counter-running surface.

[0028] The above statements regarding the further development of the first-mentioned axial shaft seal and the first-mentioned counter-running surface preferably also apply mutatis mutandis to the further axial shaft seal and the further counter-running surface. In particular, the above-mentioned means can also comprise the further axial shaft seal in addition to the first-mentioned axial shaft seal. The recess of the means is preferably further developed such that it axially projects on both sides not only beyond the web that has the first-mentioned counter-running surface, but also beyond a web that has the further counter-running surface.

[0029] The arrangement according to the invention or a preferred further development is preferably developed as part of the wind turbine gearbox described above. The pitch tube of the arrangement forms a pitch tube of the wind turbine gearbox.

[0030] The pitch tube can be fixed in an output shaft or a housing of the transmission in a rotationally fixed manner. In a preferred embodiment, however, the pitch tube is fixed in an input shaft of the transmission in a rotationally fixed manner. This allows it to be rotated relative to the output shaft and the housing.

[0031] The further development provides that the output shaft or the housing has the axial shaft seal or the counter-running surface. In this case, the output shaft is arranged coaxially with the input shaft.

[0032] In a further preferred embodiment, the pitch tube is fixed exclusively in the input shaft. This means that, apart from the input shaft, the pitch tube is not mounted or fixed in any other component of the transmission, in particular not in the output shaft or the housing. This embodiment eliminates the generator-side bearing for the pitch tube, which is common in the prior art. Accordingly, there is no need to supply this bearing with oil. The risk of bearing damage is also eliminated.

[0033] The gear mechanism is preferably further developed with a disk having a continuous recess. The recess is preferably rotationally symmetrical. In particular, the recess can be rotationally symmetrical to the above-described axis of rotation and / or to the above-described central axes.

[0034] The pitch tube runs through the recess. The disc serves as a centering disc for the pitch tube. If the radial positional deviations are too large, the pitch tube temporarily comes into contact with the disc at one edge of the recess. The disc thus prevents even greater radial positional deviations, which could otherwise lead to damage.

[0035] The use of a centring disc, as described in the advanced design, is advantageous because it can be made of a material with good sliding properties, such as Teflon or nylon. Furthermore, the disc can be mounted so that it is accessible from outside the housing. This makes it easy to replace the disc in the event of advanced wear or damage.

[0036] In a preferred embodiment, a gap extending in the radial direction between the disk or an edge of the recess and the pitch tube is narrower than a gap extending in the radial direction between the above-described web and the pitch tube or the above-described means. The width of the former gap is thus smaller than the width of the latter gap. As a result, in the event of a radial positional deviation, the pitch tube comes into contact with the disk before the web touches the pitch tube or the means. Damage to the web is thus avoided.

[0037] Preferred embodiments of the invention are illustrated in the figures. Corresponding reference numerals indicate identical or functionally equivalent features. In detail:

[0038] Fig. 1 shows an arrangement for sealing a pitch pipe;

[0039] Fig. 2 shows an alternative arrangement; and

[0040] Fig. 3 shows another alternative arrangement.

[0041] The sealing arrangement 101 for a pitch tube 103 shown in Fig. 1 has a clamping bush 105. The clamping bush 105 is non-positively fixed to an outer surface 109 of the pitch tube 103 by means of a conical clamping mechanism 107. The clamping bush 105 has a first axial shaft seal 111 and a second axial shaft seal 113. The first axial shaft seal 111 and the second axial shaft seal 113 serve to seal the clamping bush 105 against an end piece 115. The end piece 115 forms a flange 117 that can be screwed to a corresponding flange of an output shaft or a gearbox housing.

[0042] Furthermore, the end piece 115 forms a first web 119 and a second web 121. The first web 119 and the second web 121 extend radially inward from the end piece 115 or a base body of the end piece 115, i.e., in the direction of a rotational axis of the pitch tube 103.

[0043] The first axial shaft seal 111 is located on the rotor side of the first web 119. It has a sealing lip that extends from the first axial shaft seal 111 or from a base body of the axial shaft seal 111 on the generator side toward the first web 119. The sealing lip contacts a circular counter-running surface formed by the first web 119.

[0044] The second axial shaft seal 113 and the second web 121 are constructed mirror-symmetrically to the first axial shaft seal 111 and the first web 119. Accordingly, the second axial shaft seal 113 also has a sealing lip. This lip extends from the second axial shaft seal 113 or from a base body of the second axial shaft seal 1113 on the rotor side toward the second web 121. The sealing lip contacts an annular counter-running surface formed by the second web 121.

[0045] A centering disk 123 is screwed to the end piece 115. This forms a circular, through-hole in the center through which the pitch tube 103 extends. If the radial positional deviations are too great, the pitch tube 103 comes into contact with an edge of the hole in the centering disk 123 and thus bears against the centering disk 123. This prevents the first web 119 and the second web 121 from colliding with the clamping bush 105. Compared to the sealing arrangement 101 shown in Fig. 1, in the sealing arrangement 202 shown in Fig. 2, the assignments of the first seal 111 and the second seal 113 as well as the first web 119 and the second web 121 to the clamping bush 105 and to the end piece 115 are inverted. Thus, according to Fig. 2, the clamping bush 105 forms the first web 119 and the second web 121. The end piece 115 has the first axial shaft seal 111 and the second axial shaft seal 113.

[0046] The arrangement of the clamping bush 115 can also be inverted, as can be seen from the sealing arrangement 301 shown in Fig. 3. According to Fig. 3, the clamping bush 105 is arranged radially outside a bush 303. It is positively fixed in an inner, circular cylindrical surface of the end piece 115. Accordingly, the end bush 105 is axially displaceable within the end piece 115 during assembly and can thus be fixed in a suitable axial position during assembly.

[0047] As with the sealing arrangement 101 shown in Fig. 1, the first web 119 and the second web 121 of the sealing arrangement 301 shown in Fig. 3 also extend radially inward toward the pitch tube 103. The clamping bush 105 forms the first web 119 and the second web 121 according to Fig. 3.

[0048] In Fig. 3, the first axial shaft seal 111 and the second axial shaft seal 113 are also fixed to the pitch tube 103. The bushing 303 serves this purpose. This bushing is circular-cylindrical and hollow inside. It is positively fixed to the pitch tube 103. Axially, the bushing 303 is in contact with a shoulder 305 of the pitch tube 103 on one side. On the other side, it is held in place by a locking ring 307, which is inserted into a corresponding groove in the pitch tube 103. Reference numeral

[0049] Sealing arrangement pitch tube clamping bush

[0050] clamping mechanism

[0051] lateral surface

[0052] Axial shaft seal

[0053] Axial shaft seal end piece flange

[0054] web

[0055] web

[0056] Centering disc

[0057] Sealing arrangement

[0058] Sealing arrangement

[0059] socket

[0060] Paragraph

[0061] Retaining ring

Claims

Patent claims 1. Sealing arrangement (101, 201, 301) for a pitch tube (103) of a wind turbine gearbox; characterized by at least one axial shaft sealing ring (111) and at least one annular counter-running surface rotatable relative to the axial shaft sealing ring (111); wherein the pitch tube (103), the axial shaft sealing ring (111), and the counter-running surface are aligned coaxially with one another; and wherein at least one sealing lip of the axial shaft sealing ring (111) is axially clamped against the counter-running surface.

2. Arrangement (101, 301) according to claim 1; characterized in that the axial shaft sealing ring (111) is fixed in a rotationally fixed manner relative to the pitch tube (103).

3. Arrangement (101, 201, 301) according to one of the preceding claims; characterized by at least one web (119) extending around the pitch tube (103) and having the counter-running surface.

4. Arrangement (101) according to one of the preceding claims; characterized by a means (105) which is designed to be fixed in several axial positions on an outer surface (109) of the pitch tube (103) and has the axial shaft sealing ring (111).

5. Arrangement (101) according to the preceding claim; characterized in that the means (105) has a recess extending in the circumferential direction, which projects axially beyond the web (119) on both sides.

6. Arrangement (201) according to claim 1; characterized in that the counter-running surface is fixed in a rotationally fixed manner relative to the pitch tube (103).

7. Arrangement (201) according to the preceding claim; characterized by a means (105) which is designed to be fixed in a plurality of axial positions on an outer circumferential surface (109) of the pitch tube (103) and has the counter-running surface.

8. Arrangement (101, 201) according to one of claims 4, 5 or 7; characterized in that the means (105) is fixed in a force-fitting manner on a circular-cylindrical section of the outer surface (109) of the pitch tube (103).

9. Arrangement (101, 201, 301) according to one of the preceding claims; characterized by a further axial shaft sealing ring (113) arranged mirror-symmetrically to the axial shaft sealing ring (111) and a further counter-running surface arranged mirror-symmetrically to the counter-running surface and rotatable relative to the further axial shaft sealing ring (113); wherein the pitch tube (103), the further axial shaft sealing ring (113) and the further counter-running surface are aligned coaxially to one another; and wherein at least one sealing lip of the further axial shaft sealing ring (113) is clamped axially against the further counter-running surface.

10. Wind turbine gearbox with a pitch tube (103); characterized by an arrangement (101, 201, 301) according to one of the preceding claims. 11 . Transmission according to the preceding claim; characterized in that the pitch tube (103) is fixed in an input shaft of the transmission in a rotationally fixed manner; wherein an output shaft of the transmission arranged coaxially to the input shaft or a housing of the transmission has the axial shaft sealing ring (111, 113) or the counter-running surface.

12. Transmission according to the preceding claim; characterized in that the pitch tube (103) is fixed exclusively in the input shaft.

13. A transmission according to one of the preceding two claims; characterized by a disc (123) with a continuous recess; wherein the pitch tube (123) extends through the recess.

14. Transmission according to the preceding claim with an arrangement according to one of claims 3 to 5; characterized in that a radial gap extending between the disc (123) and the pitch tube (103) is narrower than a radial gap () extending between the web (119) and the pitch tube (103) or the means (105).

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