Method for manufacturing a hydrodynamic axial sliding bearing, in particular an axial sliding bearing for supporting a rotor shaft of a wind turbine

Abstract

Method for manufacturing a hydrodynamic axial sliding bearing (1), in particular an axial sliding bearing (1) for supporting a rotor shaft (11) of a wind turbine (8), comprising the steps: - Manufacturing a ring body (2) from unhardened steel by machining - Manufacturing of fastening structures (4) for fastening individual sliding bearing elements (5) by machining or non-machining one or both axial end faces of the ring body (2) - Arranging and fastening the individual sliding bearing elements (5) to the fastening structures (4) - Separating the ring body (2) to form individual ring segments (7), each of which has one or more sliding bearing elements (5).

Description

[0001] These hydrodynamic axial plain bearings are used to support heavy shafts, primarily in mechanical and plant engineering. For example, they serve as the main bearing for the rotor shaft of a wind turbine. Such shafts have diameters of one meter or more, which inevitably necessitates correspondingly dimensioned bearings to support the rotor shaft. The rotor shaft bearing is of central importance because it is directly subjected to all the forces generated by the wind interacting with the rotor blades, which are connected to the rotor shaft via the hub. Therefore, the bearings are exposed to highly dynamic loads. The shaft is supported by appropriate plain bearing elements, which are fixed in position on a support structure, with a lubrication gap remaining between the plain bearing elements and the rotor shaft.In these bearings, a lubricant, such as oil, is introduced via the sliding bearing elements, forming a lubricating film on which the rotor shaft slides. The basic operating principle of such hydrodynamic bearings for heavy shafts, such as the rotor shaft of a wind turbine, whether axial or radial, is well known.

[0002] Since, as described, the rotor shafts have considerable diameters, the support structures must therefore be dimensioned accordingly large, as they must encompass the rotor shaft.

[0003] The invention is based on the problem of providing a method for the simplified production of a hydrodynamic axial sliding bearing.

[0004] To solve the problem, the invention proposes a method for manufacturing a hydrodynamic axial sliding bearing, in particular an axial sliding bearing for supporting a rotor shaft of a wind turbine, comprising the following steps: - Manufacturing a ring body from unhardened steel by machining - Manufacturing fastening structures for fastening individual sliding bearing elements by machining or non-machining one or both axial end faces of the ring body - Arranging and attaching the individual sliding bearing elements to the mounting structures - Separating the ring body to form individual ring segments, each of which has one or more sliding bearing elements.

[0005] The method according to the invention allows the production of a simply constructed axial sliding bearing in a relatively simple, cost-effective manner, whereby the axial bearing is easy to assemble.

[0006] First, a support structure, i.e., a bearing carrier, in the form of a ring-shaped body made of unhardened steel is manufactured by machining. This can be done, for example, by turning. Then, corresponding mounting structures for attaching individual sliding bearing elements are formed on one or both opposing axial end faces of the ring-shaped body. These mounting structures are essentially interfaces to which the sliding bearing elements, often also referred to as sliding bearing pads, are attached. These mounting structures can be manufactured either by machining, for example, by turning, grinding, or drilling, or without machining, for example, using a laser.These fastening structures can be designed, for example, as corresponding recesses or receptacles or bores or other three-dimensional geometries, with corresponding fastening geometries also being provided on the sliding bearing elements.

[0007] Once the mounting structures are formed, the individual sliding bearing elements are arranged on the ring body and attached to the mounting structures. This attachment can be achieved, for example, by pressing, shrinking, screwing, or similar methods.

[0008] In a final step, the ring body is then separated to form individual ring segments, each ring segment comprising one or more sliding bearing elements. The ring body is thus radially separated, for example by machining or without machining, and divided into individual, preferably equidistant, ring segments. It can, for example, be separated into four ring segments, each rotating by 90°, or three ring segments, each with an extension of 120°, although the invention is not limited to these possibilities. The finished axial sliding bearing is therefore a segmented bearing, consisting of the individual ring segments with the sliding bearing segments arranged thereon.During assembly, the ring segments are attached to appropriate mounting structures. It is not essential that all ring segments form a perfect ring after attachment, as they merely serve as supports for the actual sliding bearing elements and have no other guiding function or similar purpose. In the assembled position, the ring segments, with the sections on their inner circumference where the sliding bearing elements are located, engage in a corresponding radial groove in the rotor shaft or in a groove between the rotor shaft and a downstream gearbox, preferably with axial support in both axial directions.

[0009] As described, in the first step the ring body is manufactured by machining an unhardened steel ring. This is preferably done by turning, but according to the invention also by drilling, whereby axial mounting recesses are formed, preferably in the area of ​​the outer edge of the ring body, via which the subsequent individual ring segments can be axially attached to an adjacent support structure, in particular a neighboring radial bearing, preferably also a hydrodynamic radial bearing, on which the rotor shaft is radially supported. Thus, in the manufacture of the ring body, the ring body is produced in its basic geometry on the one hand, and the corresponding mounting recesses are drilled on the other hand.

[0010] The fastening structures used to secure the sliding bearing elements can be manufactured, as described, by turning, grinding, and / or drilling – i.e., by machining. Any machining method that allows for the creation of the three-dimensional fastening structure is conceivable. Alternatively, the fastening structure can also be manufactured without machining using laser processing. This method also allows for the creation of corresponding three-dimensional fastening structures.

[0011] According to a convenient embodiment of the inventive method, the ring body can be heated, particularly inductively, before the sliding bearing elements are arranged and fastened. This heating simplifies the fastening of the sliding bearing elements to the mounting structures, especially if, as further provided for in the invention, the sliding bearing elements are pressed onto the mounting structures of the heated ring body. In this case, there is no fastening via separate fasteners, but rather a purely form-fit and force-fit connection. The ring body can be heated in any way, but preferably inductively, since inductive heating also allows for local heating of the areas actually to be heated.In the case of press-fitting, the fastening structures have corresponding receiving sections into which the sliding bearing elements are positively inserted with corresponding insertion sections and, after cooling, are also held in place by friction. The receiving and insertion sections can have any geometry, for example, square, round, or oval, as long as they enable a corresponding positive and frictional fit.

[0012] Alternatively, or possibly additionally, it is conceivable that the sliding bearing elements are screwed to the mounting structures using screw connections. The sliding bearing elements thus have corresponding receptacles such as bores or similar features through which the individual mounting screws are inserted, while the mounting structures, for example, have corresponding internal threaded bores into which the mounting screws are screwed.

[0013] Furthermore, it is possible that after the sliding bearing elements have been arranged and fastened, they are mechanically machined to adjust their axial height. This means that once the sliding bearing elements are in their final assembly position on the ring body, they are reworked and precisely adjusted to the required axial height during this finishing process.

[0014] In addition to the method itself, the invention further relates to a hydrodynamic axial sliding bearing, in particular manufactured according to the method of the type described above, consisting of several ring segments made of unhardened steel, each of which has one or more sliding bearing elements attached to respective mounting structures. The sliding bearing elements can be arranged only on one axial side of the ring body or the ring segments, i.e., support only on one axial side; however, preferably corresponding sliding bearing elements are arranged on both axial sides or end faces of the ring segments, so that bidirectional axial support is provided.

[0015] Preferably, each ring segment has several axial mounting points for connection to a third object, for example an adjacent bearing ring of an adjacent hydrodynamic radial sliding bearing.

[0016] The sliding bearing elements themselves can be pressed or screwed onto the ring segments.

[0017] The invention is explained below with reference to exemplary embodiments and the drawings. The drawings are schematic representations and show: Fig. 1 a schematic representation of an axial sliding bearing according to the invention, and Fig. 2 a schematic representation of an assembly situation of an axial sliding bearing according to the invention for supporting a rotor shaft of a wind turbine.

[0018] Fig. Figure 1 shows a hydrodynamic axial sliding bearing 1 according to the invention, comprising a ring body 2 made of an unalloyed steel, which was produced by machining a base material. In the region of the outer edge, a plurality of separate axial mounting receptacles 3 in the form of axial bores are formed, via which the axial sliding bearing can be screwed to a support structure, such as an adjacent radial bearing, in the mounting position.

[0019] Furthermore, located radially further inward than the mounting receptacles 3, a multitude of separate mounting structures 4 are provided, which serve to fasten individual axial sliding bearing elements 5, also referred to as axial bearing pads. The mounting structures 4 are also machined, but can also be produced without machining by laser processing. They are designed such that the mounting of the sliding bearing elements is achieved either by a positive and force fit, meaning that the sliding bearing elements 5 are pressed in, i.e., held in an interference fit. Alternatively, it is also conceivable that the mounting structures allow the fixing of the sliding bearing elements 5 by means of suitable fastening screws. A combination of interference fit and screw fastening is also conceivable.The fastening structures 4 are preferably formed on both axial end faces of the ring body 2, so that corresponding sliding bearing elements 5 are arranged on both sides of the ring body 2, and consequently the element to be supported, preferably a rotor shaft of a wind turbine, is axially supported in both directions via the axial sliding bearing 1. The fastening structures 4 on both sides of the ring body are, of course, preferably identical, so that identical interfaces are provided on the ring body 2 as well as on the sliding bearing elements 5.

[0020] After being fixed to the ring body 2 or the mounting structures 4, the sliding bearing elements 5 undergo final mechanical machining to ensure precise axial height and length, resulting in a uniform bearing surface around the circumference. In the assembled position, a narrow lubrication gap forms between each sliding bearing element 5 and the adjacent bearing surface of the component being supported, i.e., the rotor shaft. Lubricant is introduced into this gap from the side of the axial bearing 1 via the sliding bearing elements 5, forming a lubricating film over which the sliding bearing action takes place.

[0021] Once all the sliding bearing elements 5 are mounted and finished, the ring body 2 is divided along the marked parting lines 6, resulting in four ring segments 7 in the example shown. Each segment has a plurality of mounting receptacles 3 and sliding bearing elements 5. The separation is achieved by radial cuts along the parting lines 6, which can be done by machining, for example by sawing or cutting, or without machining using a laser. Thus, in the example shown, four separate ring segments 7 are formed, rotating by 90°. They can all be identical with respect to the arrangement and number of mounting receptacles 3 and sliding bearing elements 5, but the positioning of the mounting receptacles 3 and the sliding bearing elements 5 can vary slightly depending on local requirements.The axial sliding bearing 1, segmented in this way, can be easily assembled, as this only requires screwing the individual ring segments 7 to the supporting structure, such as the adjacent ring of the radial bearing, which is relatively simple. In the assembled position, the ring segments 7 again combine to form a ring shape.

[0022] A typical manufacturing route for the axial sliding bearing 1 according to the invention looks, for example, as follows: 1. Turning an unhardened base material to produce the ring body 2 and drilling the axial mounting recess 3, 2. Forming the fastening structures 4 provided on one or both sides of the ring body 2 by laser processing 3. Inductive heating of the ring body 2 and arrangement of the sliding bearing elements 5 4. Pressing the sliding bearing elements 5 into the fastening structures 4, for example by means of an axially placed press ring. 5. Final machining of the sliding bearing elements 5 for adjusting the axial height of the sliding bearing elements 5 6. Separating the ring body 2 into individual ring segments 7

[0023] Fig. Figure 2 shows an assembly example of an axial sliding bearing 1 according to the invention. The figure shows a section of a wind turbine 8 comprising several rotor blades 9 arranged on a hub 10, which in turn is connected to a rotor shaft 11, which is coupled to a gearbox 12 driving a generator 13. During operation, the hub 10 and, consequently, the rotor shaft 11 rotate due to the interaction of the rotor blades 9 with the wind, necessitating appropriate bearing support for the rotor shaft 11. In the example shown, this support is provided radially by two hydrodynamic radial sliding bearings 14, each having a bearing ring 15 on which a plurality of separate radial sliding bearing elements 16, also referred to as radial bearing pads, are arranged on the inner circumference. The two radial bearings 14 are mounted on a corresponding base structure 17 via the bearing rings 15.

[0024] The corresponding axial bearing of the rotor shaft 11, which prevents it from moving axially due to dynamically changing load conditions, is provided by an axial sliding bearing 1 according to the invention, which is in Fig. Figure 2 is also shown. As indicated by the dashed connecting line 18, the ring segments 7 are axially fixed to the adjacent bearing ring 15 of the adjacent radial bearing 14 by means of suitable connecting screws guided through the mounting receptacles 3, and are thus firmly connected to the base structure 17 or supported with respect to it. The sliding bearing elements 5 provided on both sides of the ring segments 7 engage in a groove 19 formed between an axial end face 20 of the rotor shaft 11 and an axial end face 21 of the gearbox 12. They are clearly supported in both axial directions. Reference symbol list 1 axial plain bearing 2 ring bodies 3 Mounting bracket 4 Mounting structure 5 sliding bearing element 6 dividing line 7 ring segment 8 wind turbines 9 rotor blade 10 hub 11 Rotor shaft 12 gearboxes 13 Generator 14 radial plain bearings 15 bearing ring 16 sliding bearing element 17 Basic structure 18 connecting line 19 Nut 20 Front surface 21 Front surface

Claims

[1] Method for manufacturing a hydrodynamic axial sliding bearing (1), in particular an axial sliding bearing (1) for supporting a rotor shaft (11) of a wind turbine (8), comprising the steps: - Manufacturing a ring body (2) from unhardened steel by machining - Manufacturing of fastening structures (4) for fastening individual sliding bearing elements (5) by machining or non-machining one or both axial end faces of the ring body (2) - Arranging and fastening the individual sliding bearing elements (5) to the fastening structures (4) - Separating the ring body (2) to form individual ring segments (7), each of which has one or more sliding bearing elements (5). [2] Method according to claim 1, characterized by , that the ring body (2) is produced by turning and drilling to form axial mounting recesses (3). [3] Method according to claim 1 or 2, characterized by , that the fastening structures (4) are manufactured by turning and / or grinding and / or drilling, or that the fastening structures (4) are manufactured using a laser. [4] Method according to any of the preceding claims, characterized by , that the ring body (2) is heated, in particular inductively, before the sliding bearing elements (5) are arranged and fastened. [5] Method according to claim 4, characterized by , that the sliding bearing elements (5) are pressed onto the fastening structures (4) of the heated ring body (2). [6] Method according to any one of claims 1 to 4, characterized by , that the sliding bearing elements (5) are screwed to the fastening structures (4) via screw connections. [7] Method according to any of the preceding claims, characterized by , that after arranging and fastening the sliding bearing elements (5) are mechanically machined to adjust the axial height. [8] Axial sliding bearing (1), in particular manufactured according to the method according to one of the preceding claims, consisting of several ring segments (7) made of unhardened steel, each of which has one or more sliding bearing elements (5) attached to respective fastening structures (4). [9] Axial sliding bearing (1) according to claim 8, characterized by , that each ring segment has multiple axial mounting receptacles (3) for connection to a third object. [10] Axial sliding bearing (1) according to claim 8 or 9, characterized by that the sliding bearing elements (5) are pressed or screwed onto the ring segments (7).

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