Fluid film bearing for a wind turbine

Abstract

A fluid bearing for a wind turbine including a bearing housing, a plurality of bearing pads inside the bearing housing and circumferentially distributed around a longitudinal axis of the fluid bearing, a plurality of supporting structures, each supporting structure having at least a first interface detachably connected to a respective seat provided in the bearing housing and at least a second interface detachably connected to a respective bearing pad of the plurality of bearing pads, the supporting structure including an elastomer allowing tilting of the respective bearing pad parallel to the longitudinal axis, the elastomer being interposed between the respective seat and the respective bearing pad is provided.

Claims

1. A fluid bearing for a wind turbine comprising: a bearing housing; a plurality of bearing pads inside the bearing housing and circumferentially distributed around a longitudinal axis of the fluid bearing; a plurality of supporting structures, each supporting structure having at least a first interface connected to a respective seat provided in the bearing housing and at least a second interface connected to a respective bearing pad of the plurality of bearing pads; and wherein the plurality of supporting structures comprise a plurality of elastomeric layers being interposed between two plates of a non-compressible material to allow a movement of the respective bearing pad, wherein at least some of elastomeric layers are interposed between the respective seat and the respective bearing pad, and completely encased and capsulated within the respective seat.

2. The fluid bearing of claim 1, wherein the elastomeric layers allow the movement of the respective bearing pad parallel and/or orthogonal to the longitudinal axis.

3. A fluid bearing for a wind turbine comprising: a bearing housing; a plurality of bearing pads inside the bearing housing and circumferentially distributed around a longitudinal axis of the fluid bearing; a plurality of supporting structures, each supporting structure having at least a first interface connected to a respective seat provided in the bearing housing and at least a second interface connected to a respective bearing pad of the plurality of bearing pads, wherein the supporting structures are a stack that includes a plurality of elastomeric layers and a plurality of plates made of a non-compressible material, each elastomeric layer of the plurality of elastomeric layers being interposed between two plates of the plurality of plates; wherein the stack extends between the respective seat and the respective bearing pad and allows a movement of the respective bearing pad.

4. The fluid film bearing of claim 3, wherein at least one of the plurality of elastomeric layers is completely encased within the respective seat.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

(2) FIG. 1 depicts a schematic sectional view fluid film bearing for a wind turbine according to embodiments of the present invention;

(3) FIG. 2 depicts a schematic sectional view of a first embodiment for a component of the fluid film bearing of FIG. 1; and

(4) FIG. 3 depicts a schematic sectional view of a second embodiment for the component of the fluid film bearing of FIG. 1.

DETAILED DESCRIPTION

(5) The illustrations in the drawings are schematic. It is noted that in different figures, similar or identical elements or features are provided with the same reference signs. In order to avoid unnecessary repetitions elements or features which have already been described with respect to an embodiment are not described again further in the description.

(6) FIG. 1 partially shows a fluid bearing 10 for a wind turbine (not represented as a whole). The fluid bearing 10 includes a stator portion 10a and a rotor portion (not shown as not being a specific aspect of the present invention), typically a shaft, rotating with respect to the stator portion 10a around a longitudinal axis Y of the fluid bearing.

(7) In the following the terms “longitudinal”, “radial” and “circumferential” are referred, when not differently specified, to the longitudinal axis Y of the fluid bearing 10.

(8) The stator portion 10a comprises a plurality of bearing pads 15. In operation of the fluid bearing 10, a thin layer of rapidly moving pressurized liquid or gas is established between the rotor portion and the bearing pads 15. The lack of contact between the moving parts implies that there is no sliding friction, reducing wear and vibration with respect to other types of bearings. How such this thin fluid layer is established is not a specific aspect of the present invention and therefore not described in further detail.

(9) The fluid bearing 10, in the stator portion 10a, includes a bearing housing 11 having a hollow shape circumferentially distributed around the longitudinal axis Y.

(10) The bearing housing 11 comprises an inner surface 13 longitudinally extended. The plurality of bearing pads 15 are provided inside the bearing housing 11, protruding radially from the inner cylindrical surface 13 towards the longitudinal axis Y. The bearing pads 15 are circumferentially distributed around the longitudinal axis Y. The distribution is not regular but takes into account that on a lower portion of the bearing housing 11, due to the gravity, the load is greater. Therefore, with reference to FIG. 1, which represents a vertical sectional view of the fluid bearing 10 in operative position, two bearing pads 15 are provided on a horizontal plane including the longitudinal axis Y, four bearing pads 15 are provided on an upper portion of the bearing housing 11 above the horizontal plane including the longitudinal axis Y and eight bearing pads 15 are provided on an lower portion of the bearing housing 11 below the horizontal plane including the longitudinal axis Y.

(11) According to other possible embodiments of the present invention, a different number and a different distribution of the plurality bearing pads 15 may be implemented.

(12) For each of the bearing pads 15, the fluid bearing 10 includes a supporting structure 20 for connecting the respective bearing pad 15 to the bearing housing 11.

(13) Each supporting structure 20 comprises a first interface 21 connected to a respective seat 18 provided in the bearing housing 11. In particular, each supporting structure 20 may be connected to the respective seat 18 through the respective first interface 21 in a removable manner, so that the supporting structure 20 and the respective bearing pad 15 attached thereto may be, if necessary, removed and substituted with another supporting structure 20. This may happen, for example, for maintenance purposes or when reconfiguring the fluid bearing 10 by substituting one embodiment of supporting structure 20 with another embodiment of supporting structure 20.

(14) The seat 18 is a radial recess provided on the inner surface 13 of the bearing housing 11. The seat has the shape of a parallelepiped having an opening on the inner surface 13, a plane base opposite to the opening and four plane lateral surfaces connecting the plane base to the opening. The seat may however have an alternative shape such as being circular, triangular or other multisided shape, but in any case, any lateral surface has a uniform cross section between the seats plane base and its opening. Accordingly, any lateral surface of the seat recess can encase (encircle) a lateral surface of the elastomer 30 (FIG. 2) here shown as a complete encasement of the elastomer lateral surfaces, but in alternative (not shown) the seat encases the elastomer 30 in part only.

(15) The plane base of the seat 18 is orthogonal to a radial direction of the fluid bearing 10. The four plane lateral surfaces of the seat 18 are orthogonal to a circumferential direction the fluid bearing 10, i.e. practically almost oriented according to a radial direction of the fluid bearing 10.

(16) Consequently, the first interface 21 as a parallelepiped shape for matching the radial recess of the seat 18.

(17) The supporting structure 20 further includes a second interface 22 for connecting the supporting structure 20 to the respective bearing pad 15. The second interface 22 is provided in the supporting structure 20 radially opposite to the first interface 21. In particular, each supporting structure 20 may be connected to the respective bearing pad 15 through the respective second interface 22 in a removable manner, so that the bearing pad 15 may be, if necessary for example during maintenance of the fluid bearing 10, removed and substituted with another bearing pad 15.

(18) According to the present invention, the supporting structure 20 comprises an elastomer 30 allowing tilting of the respective bearing pad 15. The elastomer 30 is interposed between the respective seat 18 and the respective bearing pad 15.

(19) According to respective embodiments of the present invention, bearing pad 15 may tilt parallel to the longitudinal axis Y, i.e. in the plane of the attached figures, or about a direction orthogonal to the longitudinal axis Y or about both directions.

(20) With reference to FIG. 2, a first embodiment of the supporting structure 20 is shown. Such supporting structure 20 comprises 2 an elastomer 30 provided as an elastomeric layer between the respective seat 18 and the respective bearing pad 15. The elastomeric layer 30 contacts the respective seat 18, the first interface 21 being therefore provided on the elastomeric layer 30. The supporting structure 20 further include a liner 32, e.g. made of steel or other non-compressible material, extending between the elastomeric layer 30 and the respective bearing pad 15. The second interface 22 is therefore provided on the liner 32.

(21) As seen in the embodiment of FIG. 2, the elastomer 30 is encased within the seat 18 and in contact within the lateral surfaces of the seat 18 and completely capsulated within the seat 18, i.e. the elastomer 30 is both encircled on its lateral surfaces by the recess lateral surface and enclosed between the bottom interface surface 21 of this recess and the liner 32 inner surface on top.

(22) According to an alternative embodiment (not shown) of the present invention the radial positions of the elastomeric layer 30 and of the, e.g. steel, liner 32 are inverted, the elastomeric layer 30 being in contact with the respective bearing pad 15 and the liner 32 being in contact with the respective seat 18.

(23) According to another alternative embodiment (not shown) of the present invention the radial position of the elastomer layer 30 is intermediate between the respective seat 18 and the respective bearing pad 15.

(24) With reference to FIG. 3, a second embodiment of the supporting structure 20 is shown. Such supporting structure 20 comprises a plurality of elastomeric layers 30 and a plurality of plates 31, each elastomeric layer 30 being radially interposed between two plates 31.

(25) The pluralities of elastomeric layers 30 and of plates 31 constitutes a stack 40 where each elastomeric layer 30 is interposed between two plates 31 and each plate 31 is interposed between two elastomeric layer 30.

(26) The stack 40 extends between the respective seat 18 and the respective bearing pad 15, the first interface 21 and the second interface 22 being respectively provided on two respective plates 31.

(27) The radial thickness and size of the elastomeric layers 30 and of the plates 31 are adjusted to achieve the limiting torsional moment about the longitudinal axis Y, which is needed for the alignment of the bearing pad 15.

(28) As seen in the embodiment of FIG. 3, several of the elastomeric layers 30 are completely encased within the seat 18, i.e. the elastomer is encircled by the lateral surfaces of the seat recess. Further as illustrated, the plates 31 of a non-compressible material are dimensioned (top and bottom surface area) slightly larger than the elastomeric layers 30, and the individual elastomers 30 can thus expand within the cavity formed between two plates 31 when the bearing pad 15 is subjected to a load.

(29) According to alternative embodiments (not shown) one or both of the first interface 21 and the second interface 22 are provided on respective elastomeric layers 30.

(30) According to yet another alternative embodiment (not shown) the stack of layers 40 is arranged in a way that all of the multiple elastomeric layers 30 are encased within the seat, and optionally a liner 32 placed on top of the stack 40 extending between the stack 40 and the respective bearing pad 15.

(31) It should be noted that the term “comprising” does not exclude other elements or steps and the use of articles “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

(32) Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

(33) 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.