Fluid film bearing, in particular for a rotor hub in a wind turbine

Abstract

A fluid film bearing comprising a first and a second component (6, 7), wherein the first component (7) comprises at least two annular sliding surfaces (14, 16, 17, 32, 33) arranged at an angle to each other, wherein the second component (6) comprises a group of respective pads (8, 9, 20, 22, 23, 28, 29, 47, 48, 49) for each of the annular sliding surfaces (14, 16, 17, 32, 33), wherein the respective pad sliding surface (10, 18, 19, 30, 31) of each pad (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) in the respective group supports the respective annular sliding surface (14, 16, 17, 32, 33), wherein the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) in each group are arranged along the second component in the first and second components. The invention relates to a bearing (2) wherein the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) are distributed in the circumferential direction of the bearing (2), wherein first, at least one pad (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of a selected group of the groups is arranged so that the spacing of the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) in the selected group along the circumference is irregular, and / or wherein second, the selected group or the selected group of the groups includes two different types of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49), and / or wherein, thirdly, the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of the selected group or a selected group of the groups are offset along the circumferential direction relative to the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of another group of the groups.

Description

Technical Field

[0001] The invention relates to a fluid film bearing, in particular for a rotor hub in a wind turbine, comprising a first and a second part rotatably connected to each other. Furthermore, the invention relates to a wind turbine. Background Art

[0002] A wind turbine typically comprises a hub to which the rotor blades are mounted, wherein the hub is rotatably supported by a nacelle or some other component of the wind turbine. The hub is typically coupled directly to the rotor of the generator to form a direct drive wind turbine or is coupled via a gearbox. The hub may be supported by one or more bearings. Typically, such bearings are formed as roller bearings. Due to the high precision required when machining these bearings, those bearings are typically very expensive, and wear can result in damage to the bearings. In order to replace a damaged component, it is typically necessary to disassemble the entire bearing. Therefore, the replacement procedure is expensive and can result in long downtimes.

[0003] A sliding bearing is known, for example, from document EP 3276192 to replace such a ball or roller bearing. The disclosed construction requires two bearings to support the drive shaft at both ends of the housing. Additional components, such as thrust bearings or thrust collars, are required to axially support the hub. An alternative bearing construction that allows a single bearing to be used in a wind turbine is disclosed, for example, in document WO 2013 / 034391A2. The bearing uses closely spaced pads mounted on a rotating outer ring of the bearing, which is connected to the hub. Summary of the invention

[0004] It is therefore an object of the present invention to further improve a bearing, in particular a bearing for use in a wind turbine, and in particular to reduce the complexity of a wind turbine using such a bearing, to reduce the wear of the bearing and / or to improve the maintainability of the bearing.

[0005] The problem is solved by a fluid film bearing, in particular for a rotor hub in a wind turbine, the fluid film bearing comprising a first and a second component rotatably connected to each other, wherein the first component comprises at least two annular sliding surfaces extending along the first component in a circumferential direction of the bearing and arranged at an angle to each other, wherein the second component comprises a group of respective pads for each of the annular sliding surfaces, wherein the respective pad sliding surface of each pad in the respective group supports the respective annular sliding surface, wherein the pads in each group are distributed along the second component in the circumferential direction of the bearing, wherein first, at least one pad of a selected group of the groups is arranged such that the spacing of the pads in the selected group along the circumference is irregular, and / or wherein, second, the selected group or a selected group of the groups comprises two different types of pads, and / or wherein, third, the pads of the selected group or a selected group of the groups are offset in the circumferential direction relative to pads of another group of the groups.

[0006] The use of at least two annular sliding surfaces and corresponding pad groups supporting these sliding surfaces allows a combined support in radial and axial directions to be achieved by the same bearing. For example, a first annular sliding surface and an associated radial pad substantially orthogonal to the radial direction can be used to provide radial support, and two pad groups can be used supporting further annular sliding surfaces, which are arranged at an angle to the axial direction of the bearing to provide axial support in both axial directions. Alternatively, for example, two annular sliding surfaces supported by corresponding pad groups can be used, which are arranged at an angle to both the radial direction and the axial direction of the bearing. In this case, each pad group can provide support in the radial direction and in the axial direction.

[0007] The described options regarding the arrangement and type of pads allow for lower complexity and cost of the bearing. Irregular spacing of the pads in one group is particularly advantageous when the axial direction of the bearing is substantially parallel to the horizontal, for example at an angle of less than 30° or less than 15° to the horizontal. This is typical for the bearing of the hub of a wind turbine. In this case, radial support is primarily required to compensate for the pull of gravity on the hub. Thus, for example, all or most of the pads that should provide radial support can be positioned so that they are in the upper half of the circumference when mounted to the inner part of the bearing or in the lower half of the circumference when mounted to the outer part of the bearing. This can reduce the number of pads required and thus reduce the complexity, cost and weight of the bearing.

[0008] Typically, the irregular spacing of the pads of the selected group results in an arrangement in which not all adjacent pads of the selected group are equidistant when measured around the circumference in a given measuring direction. This may be the case, for example, if the bearing comprises at least three pads of the group and one of the pads is offset so that it is closer to one of its adjacent pads than to another of its adjacent pads. Alternatively, two pads may be grouped, for example, in a certain section of the circumference of the bearing so that there is a relatively small distance and a relatively large distance between the pads along the circumference. In the selected group, the distances between the pads may vary, for example, by at least 10% or by at least 30% or by at least 50%.

[0009] As mentioned above, in most cases of use, the load on the bearing in the radial direction will be determined by the pull of gravity. However, it is advantageous when the bearing can also handle unexpected or rare load events (e.g., during rare wind conditions or during the installation and / or maintenance of a wind turbine). Therefore, it is advantageous to still place at least some of the pads in the upper half of the circumference of the bearing when the pads are mounted to the outer member, or to still place at least some of the pads in the lower half of the circumference of the bearing when the pads are mounted to the inner member to handle such rare load events. A smaller number of pads can be used to handle these rare load events. However, alternatively or in addition, it is also advantageous to use different types of pads in different positions. The pads that mainly provide support during rare loading events can be designed so that when they are used in the same amount as other pads, their life will be lower. Since these pads are rarely fully loaded, they can still achieve a life that is roughly the same as other pads.

[0010] As previously mentioned, the fluid film bearing according to the present invention uses at least two annular sliding surfaces with corresponding pad groups to support these sliding surfaces. The simplest way to support the annular sliding surfaces is to place pads of all groups at each circumferential position where support is required. The disadvantage of this method is that the pads of different groups need to be slightly spaced apart in the axial direction, thus extending the length of the bearing in the axial direction. By offsetting the pads of at least one group relative to the pads of another group in the circumferential direction, the pads of these groups can be placed so that if placed at the same circumferential position, they will overlap in the axial direction, thereby shortening the bearing. Shorter bearings can reduce the amount of material required for the bearing, thereby reducing the cost and weight of the bearing. In addition or alternatively, the offset between the groups can be used to allow a larger pad sliding surface for the pads of at least one group, particularly for one or more groups that provide radial support without the need for longer bearings.

[0011] When at least three pad groups are used, for example one group provides radial support and two groups provide axial support, for example only the pads providing radial support may be offset from the pads providing axial support. However, the two pad groups providing axial support may also be offset relative to each other.

[0012] In a fluid film bearing, it is necessary to provide lubricant to the contact area between the different sliding surfaces. Various lubrication methods are known in the prior art, which will not be discussed in detail. The lubrication can be, for example, flood lubrication, direct lubrication, lubrication through a spray bar or some other type of lubrication. Preferably, oil is used as lubricant in the fluid film bearing. The fluid film bearing can preferably be a hydrodynamic bearing or alternatively a hydrostatic bearing. A combination of these bearing types can also be used, with some pads being lubricated by hydrodynamic lubrication and some pads being lubricated by hydrostatic lubrication. In order to avoid excessive leakage of lubricant, the connections between the different components of the bearing are preferably sealed. For simplicity, the seals between the components are not shown or discussed in this application, as the implementation of such seals is well known in the prior art.

[0013] In a fluid film bearing, the support of one sliding surface by another sliding surface involves an indirect transmission of force, since a thin lubricating film is arranged between these surfaces. In some cases, such as at low rotational speeds in a hydrodynamic bearing, or when a pump supplying lubricant in a hydrostatic bearing is not in operation, the corresponding sliding surfaces may be in direct contact, and thus the support may be achieved by a direct exchange of force.

[0014] The number of pads of the selected group in the first semicircle of the bearing may be higher than the number of pads of the selected group in the second semicircle of the bearing. Alternatively or in addition, pads of the first type may be arranged in the first semicircle of the bearing and pads of the second type may be arranged in the second semicircle of the bearing. As previously mentioned, this is advantageous when, for example, the axial direction is substantially horizontal to provide strong support against gravity.

[0015] Only one type of pad may use a coating to form the pad sliding surface, or different types of pads may use different materials for the coating. Alternatively or additionally, different types of pads may use different materials to form the load-bearing coating of the pad or to form the corresponding contact section of the pad sliding surface. Additionally or alternatively, different types of pads may use different mechanisms to allow tilting of the contact section.

[0016] A pad for a bearing typically comprises the contact section described above and a support section for mounting the contact section to a mounting surface. The mechanism connecting the contact section and the support section typically allows the contact section to tilt in at least one direction to compensate for slight misalignments of the first and second components and to compensate for tolerances. Various methods for providing such a pad are known in the prior art and will therefore not be discussed in detail. It should be noted that in some cases only the contact section is considered to be a pad, while the support section is considered to be a pad support. In portions of the present invention that do not concern individual sections of a pad, the combination of sections discussed will simply be referred to as a pad.

[0017] The material used to form the contact section may be, for example, different types of steel. One or more coatings may be selected, for example, from babbitt, white metal, polymer or some other coating. Examples of mechanisms that allow tilting are pivots, bolt-sleeve connections or flexible supports. The flexible support may be formed, for example, by forming the support member and the contact section of the pad from the same material, and connecting these sections by a connecting member that is made of the same material but has a smaller diameter and therefore has a certain flexibility to allow a slight tilting of the pad sliding surface. Different combinations of the variants mentioned result in differences in the cost, weight and durability of the pad, and may therefore be used to provide at least two types of pads that are used in bearings to optimize these parameters.

[0018] The annular sliding surface supported by the pad sliding surfaces of the selected group of pads may be arranged at an angle to the radial direction of the bearing. In other words, the selected group of pads may be radial pads which provide at least a certain amount of radial support for the sliding surface. As previously mentioned, the use of a bearing for a hub of a wind turbine will result in a substantially horizontal axial direction. Therefore, the amount of axial support required is substantially constant around the circumference of the bearing, and it is mainly the amount of radial support required that varies. Therefore, varying the type or spacing of the radial pads is particularly advantageous.

[0019] Such radial pads may, for example, be formed by a plurality of pad groups, the pad sliding surfaces of which are at an angle of at least 10° or 20° to the radial and axial directions, preferably at an angle of between 35° and 55°, and face different axial directions. These types of pads will provide both radial support and axial support. Alternatively, at least one radial pad group may be used which is substantially orthogonal to the radial direction, for example arranged at an angle of less than 15° or 10° or 5° to the radial direction. At least one further pad group, preferably two further pad groups, may be used to provide axial support. These may be substantially orthogonal to the axial direction. In general, pads or sliding surfaces arranged at an angle to the radial direction may be considered radial pads or radial sliding surfaces. Pads and sliding surfaces arranged at an angle to the axial direction may be considered axial pads or axial sliding surfaces.

[0020] In a preferred embodiment, the first component is an outer component of the bearing, wherein at least one of the annular sliding surfaces is formed on the inner circumference of the first component, and / or wherein the corresponding pad sliding surface of at least one of the pads of the group has a convex shape. Preferably, all groups of annular sliding surfaces supporting an angle with the radial direction are convex to match the surface of the annular sliding surface which is also convex. Thus, the first component can be considered as an outer component of the bearing and the second component as an inner component of the bearing.

[0021] Using pads mounted to an inner part rather than an outer part (the inner part may in particular be stationary and the outer part may in particular be rotatable) allows easier access to the pads, in particular when fluid film bearings are used in wind turbines. In this case, the inner part typically has the general shape of a tube in the area of ​​the bearing. The inner part thus forms a natural crawl space or even a larger entry space for personnel to access the wall of the inner part to which the pads may be mounted. As discussed in more detail below, mounting the pads on the inner part may also help to avoid sharp angles at the circumferential ends of the pad sliding surface of the pad, which may also help to reduce wear.

[0022] Preferably, the corresponding pad sliding surface of the pad providing radial support has a convex shape. When the sliding surface has a convex shape, the tangent line at any point of the sliding surface does not intersect the sliding surface. Compared with pads with sliding surfaces having a concave shape, sharp angles at the edges of the radial pad sliding surface are avoided, which can help increase the life of the pad.

[0023] Preferably, the radial pad sliding surface contacted by such a pad may have the shape of a segment of a circle in a cross section orthogonal to the axis of rotation of the bearing. Preferably, this is true for each cross section orthogonal to the axis of rotation intersecting the radial pad sliding surface. The direction of the axis of rotation may also be referred to as the axial direction.

[0024] The outer part sliding surface may have a rounded shape in one or more of the cross sections in question, resulting in a similar shape of the two sliding surfaces and thus in improved support.

[0025] The first component may form an annular projection extending in the radial direction toward the second component, wherein an annular sliding surface is formed on a radial end of the projection and on both axial ends of the projection, wherein a first group of pads is arranged on one side of the projection and a second group of pads is arranged on the opposite side of the projection in the axial direction. The annular sliding surface formed on the radial end of the projection may be supported by a sliding surface of a third group of pads, the third group of pads particularly comprising radial pads.

[0026] The projection may form an outer ring of the bearing. The projection may in particular have an I-shaped cross section in a section orthogonal to the circumferential direction of the bearing.

[0027] The first component may form an inner or outer annular segment and two annular projections extending from the annular segment in radial direction toward the second component, wherein the annular sliding surface is formed on mutually facing inner surfaces of the annular segment and the annular projections, wherein all pads are arranged between the annular projections.

[0028] The pad sliding surfaces of the first group of pads, in particular the pad sliding surfaces of the radial pads, can support the annular sliding surfaces formed on the annular inner or outer section. The pad sliding surfaces of the corresponding pad group, in particular the axial pad group, can support the corresponding annular sliding surfaces arranged on the corresponding protrusions. Since the annular sliding surfaces arranged on the protrusions face each other, axial support in two axial directions can be provided.

[0029] The inner or outer annular segment and the two projections may form an inner or outer ring of a bearing, which inner or outer ring has a U-shaped cross section in a section orthogonal to the circumferential direction.

[0030] The normals of the pad sliding surfaces of two pad groups providing radial support can be inclined relative to the radial direction, wherein the pad sliding surface of a first group of these groups can face the first axial end of the bearing, and wherein the pad sliding surface of a second group of these groups can face the second axial end of the bearing.

[0031] The normals of these pad sliding surfaces may be inclined at an angle less than 90° and greater than 0° relative to the radial direction, preferably at an angle between 30° and 60°, for example at an angle of approximately 45°. By increasing the angle of inclination, a stronger support of the pad in the axial direction is achieved, while reducing the angle provides a stronger support in the radial direction. The inclination of the pads towards different ends of the bearing results in the radial pad sliding surfaces facing different directions of different groups. Thus, the two pad groups provide axial support in two directions while still providing radial support. The first component may form an annular protrusion, which extends in a radial direction towards the second component and forms two annular sliding surfaces, wherein the normals of the annular sliding surfaces are inclined relative to the radial direction towards different ends of the bearing, wherein each of the annular sliding surfaces is supported in the axial and radial directions by one of the pad groups, wherein the outer component sliding surfaces face each other or face away from each other.

[0032] The projection can in particular form an inner or outer ring of a bearing which has a tapered I-shaped or U-shaped cross section in a section orthogonal to the circumferential direction. The annular sliding surface can in particular be arranged in a V-shape in the section on the axial end of the projection, for example when forming a ring with a tapered I-shape, or in a recess formed by the projection, for example when forming a ring with a tapered U-shape.

[0033] The pads of the first group may be arranged at a different circumferential position than the pads of the second group. This may allow a shortening of the bearing in the axial direction, in particular when a tapered U-shape of the inner or outer ring is used as described above, since the pairs of pads of the different groups providing axial support from both sides do not need to be arranged at the same circumferential position and therefore do not need to be arranged at different axial positions, but may be arranged in a straight line along the circumference of the second component.

[0034] The first or second component may be formed (particularly cast) in one piece and comprise a hub for a wind turbine. This may simplify the assembly of the wind turbine and potentially reduce the amount of material required and thus in particular the weight of the bearing and the hub. Alternatively, the first or second component may be attached to the hub of the wind turbine, for example by a flange connection.

[0035] The inner or outer ring of the bearing may be a forged steel ring, which may be formed, for example, by a protrusion of the first component as described above, which may be hardened, for example, to obtain a wear-resistant and damage-resistant surface. Alternatively, it may be a cast iron ring, which may be coated to obtain a wear-resistant and damage-resistant surface. Other implementations are also possible.

[0036] The invention also relates to a wind turbine comprising a rotor having a rotor hub, the rotor hub being connected to another component of the wind turbine using a fluid film bearing according to the invention, wherein the hub is part of or mounted to the first or second component. Preferably, the hub can be mounted to an outer one of the first and second components. The connection between the respective valve component and the hub can be torque proof. The other component is preferably connected to the nacelle and / or the stator of the generator, in particular via a torsion proof connection. The component connected to the hub can also be connected to the rotor of the generator or the input stage of the gearbox via a torque proof connection.

[0037] The number of pads of the selected group in the upper or lower half of the circumference of the bearing may be higher than the number of pads of the selected group in the other half of the circumference of the bearing. Additionally or alternatively, pads of the first type may be arranged in the upper half of the circumference of the bearing and pads of the second type may be arranged in the lower half of the circumference of the bearing. These features have been discussed with respect to the bearing according to the invention. Preferably, the hub is connected to the other component by a single bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. However, the accompanying drawings are only schematic diagrams and are designed only for illustrative purposes and are not intended to limit the present invention. The accompanying drawings show:

[0039] Figure 1is an exemplary embodiment of a wind turbine according to the invention, comprising an exemplary embodiment of a fluid film bearing according to the invention,

[0040] Figure 2 yes Figure 1 A perspective view of the internal components of the bearing shown,

[0041] Figure 3 is used for Figure 1 The general shape of the radial pads in the bearing shown, and

[0042] Figure 4-13 are detailed views of various other embodiments of fluid film bearings according to the invention, which may be used in embodiments of wind turbines according to the invention. DETAILED DESCRIPTION

[0043] Figure 1 A detailed view of a wind turbine 1 is shown, comprising a rotor hub 3 rotatably connected to another component 5 of the wind turbine 1 using a fluid film bearing 2. The hub 3 is mounted to a first component 7 of the bearing 2 using a torque-proof connection. For example, a flange connection may be used. Alternatively, the hub 3 and the first component 7 may be formed (e.g. cast) as a single piece.

[0044] The first component 7 is also connected to the structure 4 using a torque-resistant connection. The structure 4 may be used to carry a rotor of a generator of the wind turbine 1 which is not provided in the structure 4 for reasons of simplicity and clarity. Figure 1 Shown in.

[0045] The second part 6 of the bearing has an annular shape and can be formed in one piece with the other part 5 or connected to the other part 5 using a torque-proof connection. The other part 5 can in particular be or carry a stator of a generator of the wind turbine 1, which is not shown for reasons of simplicity and clarity.

[0046] Since the present invention focuses on the implementation and distribution of the various pads, details regarding the lubrication of the fluid film bearings, such as seals and a pump that may optionally be used to deliver the lubricant, are omitted from the figures.

[0047] In order to radially support the first component 7, the second component 6 comprises a first group of pads 8, 9 distributed along the circumference of the second component 6. The pads 8, 9 of the group are arranged so that the spacing of the pads 8, 9 along the circumference is irregular. In this example, the pads 8, 9 of the group providing radial support are arranged only in the upper half of the circumference. Alternatively, different numbers or types of pads can be used for different parts of the circumference. This distribution is advantageous because the main load in the radial direction is usually due to the gravity acting on the hub 3.

[0048] Each pad 8, 9 has a respective pad sliding surface 10, which supports in radial direction an annular sliding surface 14 of the first component 7. The sliding surfaces 10, 14 may, for example, be coated to improve the durability of the sliding surfaces and / or to further reduce friction. Although during normal operation the sliding surfaces 10, 14 are usually not in direct contact due to a thin lubricant film disposed between the sliding surfaces 10, 14, contact between the sliding surfaces 10, 14 may occur, for example, at low rotational speeds or when a pump for conveying lubricant is not operating.

[0049] The pad sliding surface 10 has a convex shape, such as Figure 2 and 3 In particular, Figure 2 and 3 The second component 6 is shown without the surrounding first component 7, and the overall shape of the individual pads 8, 9 is schematically shown. Figure 3 As shown, the pad sliding surface 10 at least approximates the shape of a segment 15 of a circle in a cross section orthogonal to the axial direction of the bearing 2. Figure 1 The axial direction is consistent with the horizontal direction.

[0050] The convex shape of the pad sliding surface 10 closely matches the shape of the annular sliding surface 14, i.e., is at least approximately circular in the same cross section. Another advantage of using a convex surface is that sharp angles at the edges 24, 25 of the pad sliding surface 10 are avoided. This can help reduce wear of the pad sliding surface 10 and the annular sliding surface 14.

[0051] about Figure 3 With reference to the general shape of the pads 8, 9 shown in FIG, it should be noted that pads for bearings and therefore also pads 8, 9 and other pads to be described later generally allow a certain amount of tilting of the sliding surface of the respective pad relative to a support section of the pad, which is used to support the pad against a mounting surface or some other mounting point. The sliding surface is generally provided by a contact section, which is mounted to the support section by a mechanism that allows tilting, such as by a pivot or ball-and-socket connection. A flexible support may also be provided as a mechanism that allows tilting. In this case, the contact section and the support section may be formed from the same material, connected by a thinner portion of the same material, which forms the mechanism that allows tilting. Although some of the examples that follow will show these different parts, the exact type of connection between the contact section and the support section is only relevant when different types of pads are used. Therefore, for simplicity, in FIG. Figure 1-3 In some of the following figures, the pad is shown as a single piece of material.

[0052] In reference Figure 1-3In the example discussed, the pads 8, 9 are radially inserted into through holes 12 of the body 11 of the second part 6 of the bearing. Preferably, they comprise a base plate 13, which can be screwed or bolted to the body 11. Since the radial forces exerted on the radial pad sliding surface 10 must be absorbed by the connecting elements for connecting the base plate 13 to the body 11, it is preferred to use a plurality of connecting elements distributed around the circumference of the through hole 12, such as a plurality of screws or bolts.

[0053] In the example discussed, the pad sliding surface 10 and the annular sliding surface 14 are substantially orthogonal to the radial direction and are therefore able to support the first component 7 and therefore the hub 3 only in the radial direction. In order to provide axial support for the first component 7 and thus for the hub 3, the first component 7 has two further annular sliding surfaces 16, 17 which are substantially orthogonal to the axial direction of the bearing 2. The annular sliding surface 17 is supported by the pad sliding surface 19 of the second group of pads 20, 21. The annular sliding surface 16 is supported by the pad sliding surface 18 formed by the third group of pads 22, 23. Thus, the first component 7 is supported in both axial directions.

[0054] like Figure 2 As shown in particular, the pads 8, 9 of the first group are offset in the circumferential direction relative to the pads 20 to 23 of the second and third groups. This allows a shorter bearing 2 or the use of sliding surfaces 10 of pads 8, 9 that are larger in the axial direction without using a longer bearing 2.

[0055] exist Figure 1 In the cross section orthogonal to the bearing circumferential direction shown, the annular first component 7 has a shape approximately like the letter "I" and forms a protrusion extending in the radial direction toward the second component 6. An annular sliding surface 14 is formed on the radial end of the protrusion, and annular sliding surfaces 16, 17 are formed on the axial end of the protrusion.

[0056] The pads 20-24 can be replaced by being radially removed or inserted through the through holes 26 of the body 11 of the inner part 6, so that they are sandwiched between the body 11 and the first part 7. In order to allow easy maintenance of the pads 8, 9 and the pads 20-24, the hub 3 and the second part 6 and the further part 5 or a subgroup of these parts can form an internal space 27 to allow personnel to access the second part 6. As previously mentioned, the pads 8, 9 and the pads 20-24 are all radially inserted into the body 11 of the second part 6 and can therefore be easily accessed from such an internal space 27. As discussed later, for example with reference to Fig.12 and 13 , other methods for mounting the pad may also be used.

[0057] In the examples discussed above, the pad sliding surface 10 providing radial support is substantially orthogonal to the radial direction. Therefore, it is necessary to use a group of further pads 20-23 to achieve axial support of the first component 7 and therefore the hub 3. Figure 4 An alternative embodiment is shown, in which the first part 7 has a conical shape, thereby forming two annular sliding surfaces 32, 33, which are substantially parallel to the circumferential direction of the bearing 2, but are arranged at an angle to the radial and axial directions of the bearing 2. This embodiment uses two groups of pads 28, 29, each group supporting a respective one of the annular sliding surfaces 32, 33. The respective normals of the pad sliding surfaces 30, 31 for the respective groups of pads 28, 29 are inclined with respect to the radial direction. Therefore, two groups of pads 28, 29 are sufficient to provide both radial and axial support.

[0058] A plurality of pairs of these pads 28, 29 may be spaced apart along the circumference of the second component 6. Preferably, the two groups of pads 28, 29 are irregularly spaced apart around the circumference, for example a greater number of pads 28, 29 are used in the upper part of the circumference. Alternatively or in addition, two different types of pads 28, 29 are used in different parts of the circumference. Both approaches are advantageous because the load in the radial direction varies along the circumference, since the main load in the radial direction is usually caused by gravity. This is also true for the other embodiments described later.

[0059] For ease of maintenance, the pads 28, 29 are mounted in through holes 38, 39 of the body 11 of the second component 6. As previously described, the base plate 13 may be used to bolt, screw or otherwise attach the respective pads 28, 29 to the body 11.

[0060] Figure 4 A more detailed structure of the individual pads 28, 29 is also shown. Each of the pads 28, 29 comprises a support section 36 comprising a base plate 13 for fixing the respective pad 28, 29 to the body 11. The respective sliding surface 30, 31 is provided by a respective contact section 34, which contact section may, for example, be coated to provide the respective sliding surface 30, 31. The mechanism 35 connecting the contact section 34 and the support section 36 may, for example, implement a ball and socket connection or some other means to allow a slight tilting of the respective pad sliding surface 30, 31. When different types of pads are used in a pad group supporting the same annular sliding surface, as described below with reference to Figure 8 As discussed, one way to distinguish between different types of pads is to use different mechanisms 35 for different types of pads, such as using a flexible connection for some of the pads and a ball and socket connection for other pads in the group. The pads 28, 29 can be connected by moving them from, for example, Figure 1 The interior space 27 is shown removed for easy maintenance.

[0061] Figure 5 shows minor variations of the previously discussed embodiments. Figure 4 The embodiments shown are identical and therefore the same reference numerals are used for the different parts. The main difference between these embodiments is that the pads 28, 29 are mounted to the body 11 of the first part 6. Although reference is made to Figure 4 The embodiment discussed allows particularly easy removal of the pads 28, 29, since they can be removed even when forces are loaded from the first component via the pad sliding surfaces 30, 31, but this embodiment has the disadvantage that the fixing means for fixing the respective base plate 13 to the body 11 need to support the pads 28, 29 against any forces applied by the first component 7 onto the radial pad sliding surfaces 30, 31.

[0062] When using Figure 5 In the embodiment shown, the forces exerted by the first part 7 via the pad sliding surfaces 30, 31 are directly transmitted to the body 11 of the inner part 6. In this case, the pads 28, 29 cannot be removed parallel to the support axis. Instead, they are Figure 5 The pads 28, 29 can be removed orthogonally to the axis as shown by the arrow 37 in FIG. Figure 1 The interior space 27 is shown close up.

[0063] Figure 6 , 7 and 8 show the reference Figure 1-3 An alternative embodiment similar to the embodiment discussed, in that separate groups of shims are used for radial and axial support. The first difference between these embodiments is the shape of the first component 7. Although in Figures 1 to 3 In the embodiment of the first component 7, the cross section orthogonal to the circumferential direction of the bearing 2 has an I-shape, but according to Figures 6 to 8 The embodiment uses a first component 7 having a U-shape in cross section, which is formed by an annular outer section 41 and two protrusions 42, 43 extending from the annular outer section 41 toward the first component 6, as shown in FIG. Figure 6 and 7 shown.

[0064] Similar to the previously discussed embodiment, the pads 8, 9, 47, 48, 49 providing radial support for the first component 7 and the pads 20-23 providing axial support for the first component 7 are arranged at different positions along the circumferential direction of the bearing 2. Figure 8 It is obvious in Figure 8 A perspective view of the second component 6 is shown. Thus, Figure 6 and 7 Cross-sections of the bearing 2 at different locations along the circumference of the bearing 2 are shown to illustrate the interaction of the pads 8 and pads 20 , 22 with the first component 7 .

[0065] like Figure 6 As shown, the annular sliding surface 14 is formed by an annular outer section 41. The pad 8 is mounted to the body 11 of the second component 6 in substantially the same manner as in the previously discussed embodiments. Due to the relatively large gap 45 between the protrusions 42, 43 and the radial pad 8, only the pad sliding surface 14 interacts with the outer component 7.

[0066] like Figure 7 As shown, the pads 20, 22 are sandwiched between a support ring 44 formed by the body 11 of the second component 6 and corresponding protrusions 42, 43 of the outer component 7. Since there is a sufficiently large gap 46 between the pads 20, 22 and the annular outer section 41 of the first component 7, the axial pads 20, 22 interact only with the protrusions 42, 43 to axially support the first component 7. The corresponding pad sliding surfaces 18, 19 support the corresponding annular sliding surfaces 16, 17. Figure 7 The annular sliding surfaces 16, 17 in the embodiment face each other, while in accordance with Figure 1-3 In the embodiment of FIG. 5 , the annular sliding surfaces 16 , 17 which provide the same function face away from each other.

[0067] The embodiments discussed are Figure 1-3 Another difference of the embodiment of the present invention is that additional pads 47, 48, 49 are used in the pad group supporting the annular sliding surface 14, such as Figure 8 As shown. Since the further pads 47, 48, 49 are arranged in the lower half of the circumference of the bearing 2 and the bearing group only provides radial support, the bearings 47, 48, 49 are hardly loaded during normal operation of the bearing 2. Therefore, they are mainly used to provide additional radial support in rare loading situations, for example during construction or maintenance of the wind turbine or in rare wind conditions. Therefore, it is advantageous to use two different types of pads in the group, the first type of pads 8, 9 providing support during normal operation and the second type of pads 47, 48, 49 providing support in rare loading situations.

[0068] Since the pads 47, 48, 49 are rarely fully loaded, the second type of pads may be less durable than the first type of pads or provide greater friction when strongly loaded. For example, a different coating or no coating may be used for the pad sliding surfaces of the pads 47, 48, 49. Alternatively or in addition, different mechanisms allowing tilting and / or different materials for other components of the pads 47, 48, 49 may be used. Thus, the cost and weight of the further pads 47, 48, 49 may be kept low.

[0069] Fig. 9 Shown is a reference Figure 6-8Variants of the discussed embodiments. Only a small circumferential section of the bearing 2 is shown, wherein a portion of the first component 7 is cut away to show the arrangement of the pads 20-22 and one of the pad sliding surfaces 10 for radial support. To improve clarity, the different pads 20-22 are shown in slightly more detail, rather than simply as outlines as in the previous examples.

[0070] according to Fig. 9 The main difference between the embodiment of and the previously discussed embodiment is the arrangement of the different pads 20-22 that provide axial support. In the previous embodiment, two pads 20, 22 are arranged at corresponding circumferential positions, and both pads 20, 22 are supported by the support ring 44. However, according to Fig. 9 The embodiment of the present invention places all pads 20-22 for axial support at different circumferential positions. Therefore, the first group of pads 20, 21 is placed at a different circumferential position than the second group of pads 22, 23, the pad sliding surface 19 of the pads 20, 21 supports the annular sliding surface 17, and the pad sliding surface 18 of the pads 22, 23 supports the annular sliding surface 16, which is Fig. 9 The protrusion 42 in the bearing is hidden. Using only a single pad 20-22 at each circumferential position can reduce the width of the bearing, which can be advantageous in some cases.

[0071] For the previous reference Figure 4 and 5 A similar reduction in the width of the bearing 2 can be achieved with the embodiment discussed, which uses two annular sliding surfaces 32, 33, both of which are arranged at an angle to the radial direction and to the axial direction, thus supporting the first component 7 in the axial direction and in the radial direction. Fig.10 and 11 Such an embodiment is described, which shows a cross section orthogonal to the circumferential direction of the bearing 2 at different circumferential positions. Figure 4 and 5 In the context of the present invention, the same reference numerals are used for components having the same or similar purposes.

[0072] and Figure 4 and 5 The first difference of the embodiment shown is the shape of the first component 7. Figure 4 and 5 Unlike the tapered I-shape shown, the first part 7 now has a tapered U-shape with two protrusions having tapered ends, thereby forming two annular sliding surfaces 32, 33. Fig.10 and 11 In the embodiment of FIG. 5 , the annular sliding surfaces 32 , 33 face each other.

[0073] Due to this arrangement of the annular sliding surfaces 32, 33, the two pads 28, 29 cannot be arranged at the same position in the circumferential direction of the bearing 2. Instead, they are displaced a certain distance in the circumferential direction. Preferably, the pads 28, 29 are arranged so that Fig.10 The first group of pads 28 are oriented as shown and have Fig.11 The second group of pads 29 in the illustrated orientation alternates.

[0074] Fig.12 Another variant of the fluid film bearing 2 in question is shown. The overall design of the bearing 2 is similar to that of the reference Figure 1-3 The bearing 2 in question has a first, generally I-shaped part 7 which is radially supported by a group of pads 8 and axially supported by two groups of pads 20, 22. Fig.12 In the example shown, the pads 20, 22 are arranged at the same circumferential position as the pad 8. It is also possible to use different circumferential positions for the pads 8 and the pads 20, 22 and / or to place the pads 20, 22 at different circumferential positions for different axial support directions.

[0075] Reference Figure 1-3 Examples and grounds for discussion Fig.12 The main difference between the embodiments of the present invention is that the pads 20, 22 for axial support are mounted to the body 11 of the second component 6. Instead of inserting them radially between the first component 7 and the body 11, they are inserted into the axial opening 47 of the body 11 and attached to the body 11 via the base plate 13 extending over the opening, for example by screwing or bolting the base plate 13 to the body 11. This method has already been described with reference to Figure 1 See discussion of bearing 8.

[0076] The second component 6 is connected to the other component 5 via a connection 50 located outside the pad 20, thus allowing the pad 8 and the pads 20, 22 to be moved in the respective directions indicated by the arrows 37 as shown in the reference Figure 1 The interior space 27 in question is removed.

[0077] Fig.13 Another variant of the bearing 2 is shown. Fig.12 The main difference of the bearing 2 shown is the different mounting of the pad 8. Instead of attaching the pad via the base plate 13, the support section 36 of the radial pad 8 is supported directly by the body 11 of the second component 6. This may be advantageous when it is expected that the pad 8 will be strongly loaded, since otherwise these strong loads would have to be supported by the screws or bolts fixing the base plate 13 to the body 11.

[0078] According to Fig.12 Another difference of the embodiment is that a connection portion 50 with another component 5 is provided. Fig.13In the embodiment shown, the pad 20 is therefore located outside the inner space 27 formed by the further component 5 and the bearing 2. Although this arrangement may make replacement of the axial pad 20 more cumbersome, it may be advantageous in some cases, for example when a small diameter of the further component 5 is required.

[0079] Obviously, the features discussed with respect to the individual embodiments may be combined in various ways. Furthermore, the connection of the first and second components 6, 7 of the bearing 2 to various other components of the wind turbine 1 may vary. For example, the first component 7 may be formed as a single piece with the hub 3 and / or the structure 4, or the outer component 7 may be connected to one or both of these components by a different connection, for example by a flange connection. Correspondingly, the further component 5 and the second component 6 may be provided as a single piece, or they may be connected by a flange or the like. It is also possible to use the first component 7 as an inner component of the bearing 2 and the second component 6 as an outer component of the bearing 2.

[0080] Although the present invention has been described in detail with reference to the preferred embodiments, the present invention is not limited to the disclosed examples, and those skilled in the art can derive other variations from the disclosed examples without departing from the scope of the present invention.

Claims

1. A fluid film bearing comprising a first component (7) and a second component (6) rotatably connected to each other, wherein: The first component (7) comprises at least two annular sliding surfaces (14, 16, 17, 32, 33) extending along the first component (7) in the circumferential direction of the bearing (2) and arranged at an angle to each other, wherein the second component (6) comprises a group of respective pads (8, 9, 20, 22, 23, 28, 29, 47, 48, 49) for each of the annular sliding surfaces (14, 16, 17, 32, 33), wherein the respective pad sliding surface (10, 18, 19, 30, 31) of each pad (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) in the respective group supports the respective annular sliding surface (14, 16, 17, 32, 33) 7, 32, 33), wherein the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) in each group are distributed along the second component in the circumferential direction of the bearing (2), wherein, thirdly, the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of a selected group of the groups are offset in the circumferential direction relative to the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of another group of the groups, and wherein the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of these groups are placed so that if placed at the same circumferential position, they will overlap in the axial direction.

2. The fluid film bearing according to claim 1, characterized in that: The number of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of the selected group in a first semicircle of the bearing (2) is greater than the number of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of the selected group in a second semicircle of the bearing (2), and / or pads of the first type (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) are arranged in the first semicircle of the bearing (2) and pads of the second type (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) are arranged in the second semicircle of the bearing (2).

3. The fluid film bearing according to claim 1 or 2, characterized in that: First, at least one pad (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of a selected group of the groups is arranged so that the spacing of the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) in the selected group is irregular along the circumference, and / or, second, the selected group of the groups includes two different types of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49).

4. The fluid film bearing according to claim 3, characterized in that: Only one type of pad (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) uses a coating to form the pad sliding surface (10, 18, 19, 30, 31), or different types of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) use different materials for the coating, and / or different types of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) use different materials to form the corresponding contact sections (34) of the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) carrying the coating or forming the pad sliding surface (10, 18, 19, 30, 31) and / or different mechanisms (35) to allow the contact sections (34) to tilt.

5. The fluid film bearing according to one of claims 1, 2 and 4, characterized in that The annular sliding surface (14, 16, 17, 32, 33) supported by the pad sliding surface (10, 18, 19, 30, 31) of the selected group of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) is arranged at an angle to the radial direction of the bearing (2).

6. The fluid film bearing according to one of claims 1, 2 and 4, characterized in that The first component (7) is an outer component of the bearing (2), wherein at least one of the annular sliding surfaces (14, 16, 17, 32, 33) is formed on the inner circumference of the first component (7), and / or wherein the corresponding pad sliding surface (10, 18, 19, 30, 31) of at least one pad (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of the group has a convex shape.

7. The fluid film bearing according to one of claims 1, 2 and 4, characterized in that The first component (7) forms an annular protrusion extending in a radial direction toward the second component (6), wherein the annular sliding surface (14, 16, 17, 32, 33) is formed on a radial end of the protrusion and on both axial ends of the protrusion, wherein a first group of the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) is arranged on one side of the protrusion and a second group of the pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) is arranged on an opposite side of the protrusion in the axial direction.

8. The fluid film bearing according to one of claims 1, 2 and 4, characterized in that The first component (7) forms an inner or outer annular segment (41) and two annular projections (42, 43) extending from the annular segment (41) in radial direction toward the second component (6), wherein the annular sliding surfaces (14, 16, 17, 32, 33) are formed on the inner surfaces of the annular segment (41) and the annular projections (42, 43) facing each other, wherein all pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) are arranged between the annular projections (42, 43).

9. The fluid film bearing according to claim 1, characterized in that: The fluid film bearing is a fluid film bearing for a rotor hub (3) in a wind turbine (1).

10. Wind turbine comprising a rotor with a rotor hub (3) connected to another component (5) of the wind turbine (1) using a fluid film bearing (2) according to one of the preceding claims, wherein The hub (3) is part of or mounted to the first component (7) or the second component (6).

11. The wind turbine according to claim 10, characterized in that The number of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) of the selected group in the upper or lower half of the circumference of the bearing (2) is higher than the number of pads (8, 9, 20, 21, 22, 23, 28, 47, 48, 49) of the selected group in the other half of the circumference of the bearing (2), and / or the first type of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) are arranged in the upper half of the circumference of the bearing, and the second type of pads (8, 9, 20, 21, 22, 23, 28, 29, 47, 48, 49) are arranged in the lower half of the circumference of the bearing (2).

12. A wind turbine according to claim 10 or 11, characterised in that The hub (3) is connected to the other component (5) via a single bearing (2).

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