Rotor shaft sliding bearing element for a wind turbine with a rotor axis

Abstract

The invention relates to a sliding bearing element (1) for a rotor shaft (2) of a wind turbine (4) having a rotor axis (3), comprising at least the following components: - a bearing surface (5) for hydrodynamic bearing of a corresponding counter surface (6) via a bearing gap (7) between them, which in operation is covered by a bearing oil film; - a circumferential bearing surface (8) for bearing the sliding bearing element (1) on a bearing seat (9) of the sliding bearing element (1); - a hydraulic cylinder (10) by means of which bearing oil can be discharged from an oil chamber (11); - an oil supply channel (12) between the hydraulic cylinder (10) and the bearing surface (5), wherein the bearing oil discharged from the oil chamber (11) can be fed via the oil supply channel (12) to the bearing gap (7), and wherein the circumferential bearing surface (8) of the sliding bearing element (1) is supported in such a way that the sliding bearing element can move low-frictionally in the circumferential direction (13) relative to the bearing seat (9). The sliding bearing element presented here makes it possible to significantly and reliably reduce the starting torque after the hydrodynamic bearing gap has dried out.

Description

Technical Field

[0001] The present invention relates to a sliding bearing element for a rotor shaft having a rotor axis for a wind turbine generator set, a sliding bearing having such a sliding bearing element for a rotor shaft of a wind turbine generator set, a rotor having such a sliding bearing for a wind turbine generator set, and a wind turbine generator set having such a rotor. Background Technology

[0002] Wind turbines are becoming increasingly important in the energy transition and decarbonization of energy infrastructure. Onshore wind turbines can reach power outputs of up to seven megawatts (MW), while a single offshore wind turbine can exceed fifteen MW, thus forming what is known as the energy base load in the future. Here, wind turbines utilize the dominant wind, driving a generator via rotor blades and a rotor shaft connected via a hub. This generator is configured to produce current based on the provided torque. Future (offshore) wind turbines should even provide 20 MW or higher power outputs, reflected in the increased size of the rotor blades, generator, and rotor shaft.

[0003] One of the few drawbacks of wind turbine generators is their behavior during shutdowns in windless conditions or during maintenance, or their restart behavior after extended downtime. Conventional wind turbines are typically supported by rolling bearings. As rotor shaft diameters increase, hydrodynamic sliding bearings become more practical. However, after extended downtime (e.g., half an hour), dry running can occur. That is, the hydrodynamically established lubricating film between the rotor shaft and the wetted bearing surfaces in the bearing clearance diminishes to an insufficient thickness. This leads to mixed friction, resulting in increased starting torque for the wind turbine. This must be accepted, meaning the wind turbine can only be restarted at a starting wind load significantly higher than the minimum operating wind load. Alternatively, a pump must be used to lubricate the bearing as a hydrostatic bearing, which incurs additional costs and potentially increased maintenance requirements and failure probability. Summary of the Invention

[0004] Therefore, the objective of this invention is to at least partially overcome the disadvantages known in the prior art. The features of the invention are derived from the independent claims, and advantageous configurations are shown in the dependent claims. The features of the claims can be combined in any technically meaningful manner, for which reference can also be made to the explanations in the following description and the features in the drawings, including supplementary configurations of the invention.

[0005] This invention relates to a sliding bearing element for a rotor shaft with a rotor axis in a wind turbine generator set, comprising at least the following components: A bearing surface for hydrodynamic support of a corresponding opposing surface through a bearing clearance therebetween, in which a bearing oil film is present during operation. A circumferential bearing surface for supporting a sliding bearing element on a bearing housing of the sliding bearing element; A hydraulic cylinder by means of which bearing oil can be discharged from an oil chamber; An oil supply channel is located between a hydraulic cylinder and a bearing surface, wherein bearing oil discharged from an oil chamber can be supplied to the bearing clearance via the oil supply channel. In this type of bearing, the sliding bearing element is supported by its circumferential bearing surface in a low-friction manner relative to the bearing housing in the circumferential direction.

[0006] In the following description, when referring to axial direction, radial direction, or circumferential direction and the corresponding terms, the rotor axis shall be used as a reference unless explicitly stated otherwise. Ordinal numbers used in the foregoing and following description are for clarity only and do not indicate any order or rank of the components unless explicitly stated otherwise. An ordinal number greater than one does not necessarily imply the existence of another such component.

[0007] The sliding bearing element proposed herein is configured to support the rotor shaft of a wind turbine generator via its bearing surface. The bearing surface of the sliding bearing element is configured to provide hydrodynamic support to a corresponding opposing surface, wherein, during operation, a bearing clearance with a bearing oil film (lubricating film) is formed between the opposing surface and the bearing surface. This bearing oil film serves to reduce friction during rotor shaft operation. In one embodiment, a plurality of sliding bearing elements are preferably arranged circumferentially around the rotor shaft in a uniform and / or load-adaptive manner.

[0008] It is now suggested here that the sliding bearing element itself is supported with low friction relative to a bearing housing at a circumferential bearing surface. In one embodiment, the bearing housing is formed by the rotor shaft of a wind turbine generator, thereby forming a lubricating film in the bearing clearance for hydrodynamic support during the (normal) rotational operation of the rotor by the sliding bearing element relative to the bearing housing (e.g., nacelle) of the respective wind turbine generator. Additionally, the circumferential bearing surface for low-friction support of the sliding bearing element is therefore arranged on the sliding bearing element and located radially inside the hydrodynamic bearing clearance.

[0009] In an alternative embodiment, the bearing housing is arranged radially outside the rotor shaft, i.e., within the bearing housing (e.g., nacelle) of the wind turbine generator set. Additionally, the circumferential bearing surface for low-friction support of the sliding bearing element is therefore arranged on the sliding bearing element and located radially outside the hydrodynamic bearing clearance.

[0010] Due to the low-friction support of the sliding bearing element, the sliding bearing element can move relative to its bearing seat (either on the housing side or the shaft side) due to the increased friction at the bearing surface (due to the lack of a hydrodynamic lubrication film, even to static friction). The frictional resistance at the circumferential bearing surface is designed such that, even when the hydrodynamic effect of the lubrication film (in the bearing clearance) is insufficient, the resulting frictional force is large enough that the sliding bearing element circumferentially follows the applied torque from the corresponding opposing surface. Thus, the required starting torque is reduced to a desired limit via the circumferential bearing surface, and operation can be resumed at lower wind speeds even after a prolonged rotor shutdown.

[0011] In one embodiment, the sliding bearing element is movably supported relative to the bearing housing (e.g., bearing case) at its circumferential bearing surface by means of a self-lubricating material pair. For example, such a material pair is chosen where one party has a coating, such as a sliding layer, preferably impregnated with a predetermined amount of lubricant, to at least achieve mixed friction and have sufficiently low frictional resistance, thereby reliably preventing, for example, overheating and / or wear. In a (preferred alternative) embodiment, the sliding bearing element is circumferentially movably supported with low friction by means of rolling elements at its circumferential bearing surface. For example, the rolling elements are balls in a ball bearing support. It should be noted that in a preferred embodiment (where there is no active return system for returning the sliding bearing element to its target position during normal operation), the frictional resistance at the circumferential bearing surface (together with the opposing bearing housing) (from a resting state) is less than the frictional resistance in the bearing clearance when no hydrodynamic fluid friction is established, but greater than the hydrodynamic fluid friction itself.

[0012] However, in order to restore a sufficiently thick bearing oil film—that is, to restore the lubricating film in the bearing clearance to achieve the desired (or required) low frictional resistance—it is proposed to arrange an oil supply channel between the oil cavity for holding the bearing oil and the bearing surface. Therefore, the oil supply channel is arranged to supply bearing oil to the bearing clearance between the bearing surface and the corresponding opposing surface. For example, such an oil supply channel has a through bore (and thus an opening) leading to the oil cavity in the bearing surface. Furthermore, the opening of the oil supply channel on the bearing surface side is arranged, for example, in the central region of the bearing surface, at least equidistant from the central region relative to the opposite edge of the bearing surface, preferably equidistant from the opening of the oil supply channel on the bearing surface side.

[0013] It should be noted that, under design operating conditions, the lubricating film in the bearing clearance has at least reached the desired thickness by the time the sliding bearing element reaches its maximum circumferential motion. Alternatively, at least at that point, the frictional limit for restarting the wind turbine generator has been reduced to below, but has not yet reached the low and desired frictional resistance of a hydrodynamic sliding bearing support in conventional operation.

[0014] A hydraulic piston allows bearing oil to be discharged from the oil chamber, enabling oil supply to the bearing clearance even when the rotor shaft is not rotating. It should be noted that the hydraulic piston is preferably not designed to maintain static pressure for extended periods, but rather to pump a single volume from the oil chamber into the bearing clearance via the supply channel in a single stroke. In one embodiment, when the hydraulic piston returns to its starting position, bearing oil is no longer supplied to the bearing clearance in a static manner during this period. This makes the system very simple to maintain and allows it to be designed for maintenance-free operation for the desired lifespan. Therefore, the hydraulic piston, oil chamber, and supply channel preferably form a single-stroke system, wherein the displacement volume of the oil chamber is particularly preferably designed to be sufficiently large for the duration of the designed start-up phase.

[0015] It should be noted that in order to achieve efficient operation during the output torque phase of a wind turbine (with a rotating rotor), there is a purely hydrodynamic support without mixed friction, meaning that no pressure is established for the hydrostatic support.

[0016] In one embodiment, such a sliding bearing element (or a plurality of thereof, such as two or three) is arranged only in a predetermined section along the circumference (i.e., arranged according to load), for example, in the region within the Earth's gravitational field where the load is highest due to gravity. This is, for example, in a two-point support, near the underside of the rotor hub (relative to a 12-hour reference system aligned with the Earth's gravitational field at the 6 o'clock position, for example, between 4 o'clock and 8 o'clock) and further away above the bearing (in the clock reference system, for example, between 10 o'clock and 2 o'clock).

[0017] It should be noted that two-point support is not always necessary, nor is every bearing necessarily designed as a sliding bearing. It should also be noted that while it is advantageous to use radial bearings due to the main load (the rotor's weight load), in one implementation, it is equally advantageous and / or necessary to use axial bearings to achieve sufficiently low starting torque. Furthermore, skewed bearings are used, for example, which produce significantly different load distributions. For instance, such load distributions create areas of highest load due to rotor weight. For a first skewed bearing in this so-called O-shaped arrangement, this area is located below the rotor hub, while for a second skewed bearing in this O-shaped arrangement, this area is located further above the hub. If another bearing (e.g., a purely radial bearing) is also present in this bearing arrangement, such a corresponding area of ​​highest load may not exist there, or this area may be primarily determined by other effects, such as shaft deflection due to the conflict between starting torque and generator torque.

[0018] Furthermore, in an advantageous embodiment of the sliding bearing element, it is suggested that the hydraulic cylinder be driven by the circumferential movement of the sliding bearing element relative to the bearing housing, wherein, preferably, the hydraulic cylinder is fixed circumferentially relative to the bearing housing.

[0019] It is suggested here that the hydraulic cylinder be arranged on the sliding bearing element in such a way that the hydraulic cylinder necessarily moves relative to the bearing housing and is thus driven by the circumferential movement of the sliding bearing element. Therefore, the relative movement of the hydraulic cylinder is ensured by the movement of the sliding bearing element, and consequently, the bearing oil is ensured to be discharged from the oil chamber and delivered into the bearing clearance via the oil supply channel.

[0020] In a preferred embodiment, the hydraulic cylinder is fixed relative to the bearing housing such that when the sliding bearing element moves relative to the bearing housing, the associated hydraulic piston is moved into the oil chamber. This results in the discharge end of the hydraulic piston discharging bearing oil from the oil chamber and (to establish the required lubricating film) pumping bearing oil into the bearing clearance via the supply channel. Consequently, the rotor shaft hydrostatically floats, wherein, if necessary, even before the associated bearing clearance is finally established to the desired height, the rotor shaft begins to rotate (e.g., under mixed friction), thus the hydrodynamic component contributes earlier to the rotor shaft's floating (i.e., the establishment of the lubricating film).

[0021] Furthermore, in an advantageous embodiment of the sliding bearing element, it is recommended that the sliding bearing element be preloaded circumferentially by means of at least one energy storage element.

[0022] In one embodiment described above, the frictional relationship between the circumferential bearing surface and the (dry, i.e., insufficiently hydrodynamically driven) bearing surface was illustrated. Alternatively or additionally, it is suggested here that the resistance to the movement of the sliding bearing element relative to its bearing housing is determined by the sum of: the frictional resistance at the circumferential bearing surface, the discharge resistance in the oil cavity (which is largely generated by the rotor mass component acting on the sliding bearing element), and at least one energy storage element. This sum of forces is designed to be less than the frictional force at the dry bearing surface. This ensures that the hydraulic cylinder is driven in this condition.

[0023] Simultaneously, for normal operation (i.e., when there is sufficient hydrodynamic force on the bearing surface), the at least one energy storage element ensures sufficient reaction force to counteract the initiation of movement of the sliding bearing element (and the hydraulic cylinder). This energy storage element is thus preloaded circumferentially such that during normal operation, the sliding bearing element remains in its circumferential position, and during (dry) start-up, after inducing relative movement between the sliding bearing element and its bearing housing, it moves the sliding bearing element back to its initial position.

[0024] In one embodiment, at least one, preferably all, of the energy storage elements is configured as a compression spring. For example, such an energy storage element is configured as a solid spring, a helical compression spring, a disc spring, or a leaf spring and / or as a spring assembly and / or combined with a damper. In another embodiment, at least one, preferably all, of the energy storage elements is configured as a tension spring. For example, the energy storage element is configured as a solid spring, a helical tension spring, and / or a spring assembly and / or combined with a damper. The energy storage element is preferably disposed between a wall of the bearing housing and the sliding bearing element, preferably located at or within an oil groove.

[0025] Furthermore, in an advantageous embodiment of the sliding bearing element, it is recommended that the bearing housing include an oil groove, or that the bearing housing, and preferably also the circumferential bearing surface, be arranged in the oil groove during use.

[0026] In hydrodynamic supports, oil grooves are typically provided in the bearing housing. It is recommended that the circumferential bearing surface be arranged within the oil groove of the bearing housing. Thus, by means of such an oil groove, the circumferential bearing surface is configured to support the sliding bearing element with low friction within a precise limit range. Here, the support device for the sliding bearing element, preferably the sliding bearing element itself, is at least partially immersed in the oil groove. In addition to the low-friction support of the sliding bearing element, improved corrosion resistance of the circumferential support (and preferably the at least one energy storage element) is also achieved.

[0027] In an advantageous embodiment, the oil sump is configured as a bearing oil reservoir within an oil chamber. Here, the bearing oil that is forced into the bearing clearance from the oil chamber during startup is drawn back into the oil sump, preferably by means of a hydraulic piston. Preferably, the bearing oil squeezed out of the bearing clearance (by gravity) is guided into the oil sump by the oil sump.

[0028] Furthermore, in an advantageous embodiment of the sliding bearing element, it is suggested that the hydraulic cylinder can be connected in such a way as by means of a preferably passive directional valve, so that... During relative motion in the circumferential direction, the bearing oil is correspondingly discharged from the oil chamber by the hydraulic cylinder, and thus supplied to the bearing surface through the oil supply channel. When opposite relative movements occur along the circumference, the hydraulic cylinder draws bearing oil into the oil chamber accordingly. Preferably, bearing oil can be drawn from the oil sump, and more preferably, it is used in conjunction with a sliding bearing element according to one embodiment described above.

[0029] When the hydraulic piston is driven in a discharge manner, bearing oil can only be supplied via the oil supply passage on the bearing surface using the directional valve described herein. When the hydraulic piston is driven rearward, in one embodiment, bearing oil can be drawn in via a conduit from a reservoir using the directional valve described herein. Preferably, the directional valve is configured as passive, i.e., switching based on the pressure differential generated by the piston movement of the hydraulic piston. For example, such passive directional valves are conventionally constructed in the form of spring-preloaded closing bodies for the respective flow directions. In an alternative embodiment, the switching body is active, for example, constructed electromechanically, and also includes a sensing device, such as a pressure sensor.

[0030] In a preferred embodiment, bearing oil can be drawn from an oil reservoir (e.g., as described above) via a hydraulic cylinder through a corresponding switching state of a directional valve. See the foregoing description for further details.

[0031] Furthermore, in an advantageous embodiment of the sliding bearing element, it is recommended that rolling elements, preferably needle rollers, be arranged between the circumferential bearing surface of the sliding bearing element and the corresponding bearing housing, and / or the bearing housing preferably operates wet in an oil groove, particularly preferably, in accordance with a sliding bearing element according to an embodiment described above.

[0032] To ensure reliable, low-friction operation of the sliding bearing element in the circumferential direction, it is recommended to arrange rolling elements between the circumferential bearing surface and the corresponding bearing housing. In one embodiment, these rolling elements are constructed as balls, which are arranged in a (technically approximate) point contact manner between the circumferential bearing surface and the bearing housing. In an alternative embodiment, the rolling elements are constructed as cylinders. Due to the geometry of the rolling elements, rolling occurs in a (technically approximate) line contact manner, thereby providing a large area of ​​contact with a smaller installation space requirement, and thus providing high load-carrying capacity. It should be noted that the rotor mass component acting on such a sliding bearing element is significant, and the rolling elements remain constant during normal operation, thus being loaded in the same position for a long time for almost the entire expected lifespan.

[0033] In a preferred embodiment, the rolling element is constructed as a needle roller, wherein the needle roller has a smaller diameter but a longer axial extension than in cylindrical rolling element embodiments. Using a needle roller form of rolling element also allows for longer line contact due to the longer axial extension compared to cylindrical elements, while exhibiting lower radial mounting space requirements. Simultaneously, the longer line contact of the needle roller results in laterally stable rolling between the circumferential bearing surface and the bearing housing.

[0034] Alternatively or additionally, the rolling elements are arranged in oil grooves within the bearing housing and are configured to operate wet within these grooves. In addition to further reducing friction, the oil grooves in which the rolling elements roll also improve their corrosion resistance. For example, such oil grooves are constructed as described above. See the foregoing description for further details.

[0035] Furthermore, in an advantageous embodiment of the sliding bearing element, it is recommended to form a section on the bearing surface that experiences the maximum load under the gravity of the supported rotor shaft in the Earth's gravitational field. This section is arranged from a central angle line parallel to the Earth's gravitational field, within a circumferential angle range of ±30°, preferably ±15°, and particularly preferably ±5° above and / or below.

[0036] Depending on the arrangement of the rotor shaft bearings, the rotor's mass must be borne by one bearing below and another above in the Earth's gravitational field. During the transition from rest to normal operation, the load caused by mass is typically the highest and most decisive. It is recommended that one or more such sliding bearing elements with circumferential bearing surfaces be arranged only in the resulting maximum load zone.

[0037] Here, the circumferential angle range is defined relative to a line perpendicular to the Earth's gravitational field and intersecting the rotor shaft as the zero line (i.e., the 0° position). Therefore, this line is a central angle (or radius) of the circular cross-section of the rotor shaft to be supported, parallel to the Earth's gravitational field, i.e., at the 6 o'clock position in the cross-sectional view. The ±30° range thus corresponds to an angle of 60° and angular positions from 330° to 30°, or, according to the unit circle definition (starting at parallel to the Earth's surface and rotating counterclockwise), 240° to 300°. For the maximum load above the Earth's gravitational field, the corresponding position is the 12 o'clock position. The ±30° range, while also corresponding to an angle of 60°, corresponds to angular positions from 150° to 210°, or, according to the unit circle definition (starting at parallel to the Earth's surface and rotating counterclockwise), 60° to 120°.

[0038] According to another aspect, a sliding bearing for the rotor shaft of a wind turbine generator set is proposed, having at least the following components: Multiple sliding bearing elements, each having a bearing surface for supporting corresponding opposing surfaces through a bearing clearance therebetween that is covered by a bearing oil film during operation, wherein at least one sliding bearing element is constructed according to one embodiment described above. Bearing housing; and Oil sump and / or external source for providing bearing oil to the corresponding bearing clearance. Preferably, at least one bearing housing is included, and preferably, a circumferential bearing surface associated therewith is arranged in an oil groove.

[0039] To support the rotor shaft of a wind turbine generator, for example inside the nacelle, it is recommended to use at least one sliding bearing, preferably at least as a so-called main bearing or a radial bearing of the main bearing. However, it is also advantageous to use sliding bearings as axial bearings and / or as auxiliary bearings.

[0040] The components of the sliding bearing are housed within a bearing housing, wherein preferably the components are protected from external influences within the bearing housing. Preferably, one or more bearing seats are formed within the bearing housing, and more preferably, an oil groove is also maintained. Alternatively or additionally, the respective bearing seats are surrounded by or fixed to the rotor shaft in a rotational manner. In this case, the bearing housing forms a opposing surface relative to the hydrodynamic bearing surface, or the respective components are fixed thereon.

[0041] The sliding bearing comprises multiple sliding bearing elements, each forming a hydrodynamic support, specifically achieved by means of a bearing clearance between the bearing surface of the relevant sliding bearing element and a corresponding opposing surface of the rotor shaft or bearing housing. For this purpose, the bearing clearance is covered with a bearing oil film (lubricating film). In one embodiment, some, preferably multiple, sliding bearing elements are of a conventional construction (i.e., without a circumferential bearing surface, preferably fixed to a bearing housing), wherein at least one, preferably two or three, sliding bearing elements are constructed according to one embodiment described above. See the above description for further details.

[0042] In addition, an external source and / or oil sump are provided for supplying bearing oil to the bearing clearance. In a preferred embodiment, the bearing oil source and / or oil sump can be connected to the bearing clearance via an oil supply channel through a reversing valve of the sliding bearing element in one of the aforementioned embodiments, specifically as described above, for establishing a hydrostatic lubrication film by means of a hydraulic cylinder.

[0043] The sliding bearing is configured to achieve particularly low starting torque for large and / or heavy-duty shafts (e.g., rotor shafts of multi-megawatt wind turbines). Simultaneously, high fail-safety is required, for example, in the event of electronic and / or lubrication pump failures, and / or due to the robust construction of the sliding bearing element with circumferential bearing surfaces and hydraulic cylinders, it is particularly less prone to failure compared to embodiments with comparable functional ranges.

[0044] According to another aspect, a rotor for a wind turbine generator set is proposed, having at least the following components: A rotor shaft with a rotor axis; At least one sliding bearing according to one embodiment described above; Multiple rotor blades; The hub, through which the rotor blades are connected to the rotor shaft. The rotor shaft is supported in the axial and / or radial directions by means of the hydrodynamic bearing surfaces of the sliding bearing elements, enabling it to rotate about its rotor axis.

[0045] The wind turbine generator set is configured to convert wind energy into electric current through a rotor that can rotate under the action of airflow and a generator connected in a manner that transmits torque.

[0046] For this purpose, the generator is connected by a rotor shaft, which is configured to rotate about the rotor axis.

[0047] To support the rotor shaft, at least one sliding bearing as described above is provided. Preferably, multiple sliding bearings are arranged around the rotor shaft, wherein the rotor shaft (e.g., its cylindrical surface) forms corresponding opposing surfaces for the bearing surfaces of the sliding bearing elements. Alternatively, the sliding bearing elements are fixed to the rotor shaft in a rotational manner, while the opposing surfaces are formed on the housing side.

[0048] To convert wind energy into electricity, multiple rotor blades are installed. These rotor blades convert incoming wind into torque in an aerodynamic manner, thereby rotating the rotor shaft, and converting rotational energy into electrical energy at the generator during load operation.

[0049] The force transmission from the rotor blades to the rotor shaft is achieved via the hub. An adjustment transmission mechanism is usually provided in the hub to adjust the pitch of the rotor blades (or their flow profile) according to the wind speed, and even to turn them into a neutral position when necessary (e.g., in a storm).

[0050] In addition, a hydrodynamic bearing surface is provided for supporting the rotor shaft. Preferably, one or more sliding bearing elements are provided for axial and / or radial support of the rotor shaft. In one embodiment, for example for axial support, double-sided steps or grooves (and radially immersed bearing elements) are formed on the rotor shaft. It should be noted that in one embodiment, two or more bearing positions with axial spacing relative to the rotor axis are provided, wherein preferably only one is configured for axial support, thus forming a so-called fixed-floating bearing arrangement.

[0051] As previously described, the rotor shaft is supported by low friction with a particularly low starting torque using at least one sliding bearing according to one embodiment described above. Simultaneously, high fail-safety is required, for example, in the event of failure of the electronics and / or the lubricating oil pump, and / or due to the robust structure of the sliding bearing elements with circumferential bearing surfaces and hydraulic cylinders, making it particularly less prone to failure compared to embodiments with comparable functional ranges.

[0052] On the other hand, a wind turbine generator set is proposed, which has Towers with a vertical axis; A nacelle with a generator, wherein the nacelle is mounted on a tower and is capable of rotating about a vertical axis by means of a yaw system; and A rotor rotatable about its rotor axis according to one embodiment described above. The rotor shaft is connected to the generator in a manner that transmits torque, so that its rotation around the rotor axis is converted into electric current.

[0053] It should be noted that sliding bearing elements or sliding bearings (or radial and / or axial bearings) are particularly advantageous for the bearing locations explicitly mentioned in wind turbine generator sets. However, the use of sliding bearing elements or sliding bearings is not limited to this, nor is it limited to wind turbine generator sets.

[0054] The wind turbine generator set is configured to convert wind energy into electric current through a rotor that can rotate under the action of airflow and a generator connected in a manner that transmits torque.

[0055] The nacelle is configured to support, and preferably enclose, functional components for energy conversion, with a streamlined outer shape. The nacelle is rotatable about a vertical axis relative to the tower, allowing the rotor to be oriented according to operating conditions (e.g., according to the current wind direction), i.e., oriented by means of a so-called yaw system.

[0056] The rotor and its blades are connected to the generator indirectly (e.g., via a gearbox and / or overload clutch) or directly in the nacelle via its rotor shaft to generate electricity. The wind turbine generator set includes a rotor shaft supported by a hydrodynamic sliding bearing, which, as previously described, is supported with low friction at a particularly low starting torque by means of at least one sliding bearing according to one embodiment described above. Simultaneously, high fail-safety is required, for example, in the event of failure of electronic components and / or lubrication pumps, and / or due to the robust construction of the sliding bearing elements with circumferential bearing surfaces and hydraulic cylinders, making it particularly less prone to failure compared to embodiments with comparable functional ranges. Attached Figure Description

[0057] The invention will now be explained in detail with reference to the accompanying drawings illustrating the preferred configuration, within the relevant technical context. The invention is by no means limited to these purely schematic drawings, which should be noted as not being drawn to scale and not suitable for defining dimensional relationships. The figures show: Figure 1 A wind turbine generator set having a nacelle and a rotor; Figure 2 A rotor shaft with radial and axial bearings is shown in a schematic side view; Figure 3 The schematic front view shows two sliding bearing elements of a sliding bearing; and Figure 4 The schematic spatial detail diagram shows the following based on... Figure 3 Two sliding bearing elements of a sliding bearing. Detailed Implementation

[0058] exist Figure 1 A wind turbine generator set 4 is shown, comprising a nacelle 31 and a rotor 26. The vertical axis 30 of the tower 29 (shown horizontally here) is oriented vertically in the Earth's gravitational field 19, while the rotor axis 3 of the rotor shaft 2 (shown vertically here) is oriented horizontally in the Earth's gravitational field 19 (typically slightly tilted, e.g., the hub 28 is tilted upwards from the ground surface by about 5° [five degrees] to 7°). The nacelle 31, located at the top of the tower 29, is supported with low friction relative to the tower 29 by means of a yaw system 33 and is configured to rotate about the vertical axis 30. The nacelle 31 carries and encloses a generator 32 and (at least most) the rotor shaft 2, as well as bearing assemblies for the rotor shaft 2 (e.g., constructed as sliding bearings 24). The bearings shown are represented as fixed bearings with radial and axial supports. For example, this is the so-called main bearing for the rotor 26. Further support (by means of auxiliary bearings) is provided for the rotor shaft 2, for example, integrated into the generator 32. A hub 28 is connected to the rotor shaft 2 (located in front of the direction opposite to the airflow direction during power generation operation), and multiple (e.g., three, but two are visible here) rotor blades 27 are connected to this hub, thereby forming a rotor 26 capable of rotating about the rotor axis 3. Figure 2 An example of a possible implementation of the rotor 26 and the generator 32 in the nacelle 31 is shown and will be described below.

[0059] exist Figure 2 In the schematic side view, a rotor shaft 2 capable of rotating about its rotor axis 3 is shown (e.g., applicable to...). Figure 1In the wind turbine generator set 4 shown, two truncated rotor blades 27 of the connected hub 28 and rotor 26 are shown on the left side of the figure, while a (purely optional) gearbox 34 and a connected generator 32 are shown on the right side. The Earth's gravitational field 19 in the figure is oriented from top to bottom. In this embodiment (one of many possible embodiments), the rotor shaft 2 is rotatably supported with low friction by means of a bearing assembly having a fixed bearing (shown on the right side of the figure) and a floating bearing (on the left side). At least one, preferably both, of the bearings in the bearing assembly are constructed as sliding bearings 24, and bearing oil is required to supply them.

[0060] For example, at least one of the bearings is configured as a hydrodynamic sliding bearing 24. Figure 3 and Figure 4 In this paper, a possible embodiment of the sliding bearing element 1 of the segmented sliding bearing 24 is shown as an example of a radial bearing, and is described below.

[0061] exist Figure 3 In the schematic front view, two sliding bearing elements 1 of a sliding bearing 24 are shown, arranged in a circumferential angular range 23 between 5 o'clock and 7 o'clock (i.e., ±30° relative to the central angle 22 parallel to the Earth's gravitational field 19), for example, in the maximum load section 21 of the shown sliding bearing 24. For example, more bearing sections are distributed around the circumference of the rotor shaft 2, wherein these bearing sections preferably employ a conventional construction. The rotor shaft 2 is constructed here as a hollow shaft, and is therefore represented in the center as a ring in this schematic diagram, with its rotor axis 3 shown. A bearing housing 25 is schematically shown around the rotor shaft 2, and in the illustrated embodiment, the sliding bearing elements 1 are held in corresponding bearing seats 9 within the bearing housing 25, meaning that the rotor shaft 2 rotates relative to the sliding bearing elements 1 during normal operation. Corresponding to this configuration, the rotor shaft 2 has an opposing surface 6 on its outer circumference (e.g., integrally formed), which is configured to directly contact the hydrodynamic bearing surface 5 of the sliding bearing elements 1 (and, if necessary, more bearing sections). It should be noted that, for the sake of clarity, the reference numerals in the accompanying drawings are used interchangeably on only one of the two sliding bearing elements 1. Preferably, the two sliding bearing elements 1 are identical in construction.

[0062] During normal operation, with the help of bearing oil and due to the rotation of the rotor shaft 2 around its rotor axis 3 in the circumferential direction 13, a lubricating film 7 is hydrodynamically formed between the opposing surfaces 6 of each sliding bearing element 1 and the bearing surface 5, thereby achieving the desired low coefficient of friction or low resistance friction torque.

[0063] The special feature of the sliding bearing elements 1 shown here is that they are themselves supported relative to their respective bearing seats 9 (here, bearing housing 25) by means of their circumferential bearing surfaces 8. Their exact functions will be explained below. Figure 4 This will be explained in the text. It should be noted in advance that when the bearing clearance 7 dries up, the frictional torque between the rotor shaft 2 and the associated sliding bearing element 1 increases. As a result, the associated sliding bearing element 1 is driven along the circumferential direction 13 by the rotor shaft 2 (e.g., during startup) through the resulting frictional engagement.

[0064] exist Figure 4 In the schematic spatial detail diagram, it is shown that according to Figure 3 Two sliding bearing elements 1 of a sliding bearing 24 are shown. To make the two sliding bearing elements 1 clearly visible, the rotor shaft 2 is shown as transparent. In the sliding bearing element 1 on the right side of the diagram, the bearing surface 5 is clearly visible. During normal operation, the opposing surface 6 of the rotor shaft 2 slides on it via a hydrodynamically formed lubricating film 7. However, after a period of downtime, this bearing clearance 7 may dry out (resulting in insufficient thickness of the lubricating film 7), generating mixed friction between the opposing surface 6 and the bearing surface 5, thus significantly increasing the starting torque that needs to be overcome compared to the frictional torque during normal operation.

[0065] Through the circumferential bearing surfaces 8 (located on the lower side in the illustration) opposite the bearing surface 5, each sliding bearing element 1 is supported with low friction relative to the bearing housing 9 (relative to the bearing shell 25), and thus can move with low friction along the circumferential direction 13 with the rotor shaft 2 within a limited path. In the illustrated embodiment, rolling elements 17 (optionally constructed as needle rollers 18) are provided between the bearing housing 9 and the circumferential bearing surfaces 8 of the sliding bearing elements 1. Preferably, the bearing housing 9 is arranged in an oil groove 15, thereby configuring the rolling elements 17 for wet operation.

[0066] In addition, a hydraulic cylinder 10 and an oil chamber 11 (illustrated by dashed lines in the sliding bearing element 1 located on the right side of the diagram) are provided, and here (optionally) configured as a passive system. The hydraulic cylinder 10 is supported relative to the bearing housing 9, that is, supported here on a (radial) wall 35 (preferably fixed to this wall 35). When the sliding bearing element 1 moves relative to the bearing housing 9 in the circumferential direction 13, its hydraulic piston (not visible here) is forced into the oil chamber 11 along its stroke axis 38, thereby reducing the volume of the (pump) filled with bearing oil in the oil chamber 11. As a result, the bearing oil is pumped into the bearing clearance 7 through the oil supply channel 12 (here a drilled hole between the bearing surface 5 and the oil chamber 11 via a reversing valve 16 and a check valve 39), thereby hydrostatically establishing a lubricating film 7. Therefore, the coefficient of friction and the resulting resistive frictional torque are significantly reduced. It should be noted that in one embodiment, mixed friction still exists at this time, that is, the level of lubricating film 7 formed due to hydrodynamic establishment during normal operation has not yet been reached.

[0067] In this illustrated embodiment, the hydraulic piston is also passively used to replenish bearing oil to the oil chamber 11 again (optionally). For this purpose, two energy storage elements 14, configured as helical compression springs, are arranged between the radial wall 35 and an opposing wall 36 of the sliding bearing element 1. These energy storage elements 14 are clamped to act in opposition to the ingress movement of the hydraulic piston along its stroke axis 38. Once the friction between the opposing surface 6 of the rotor shaft 2 and the bearing surface 5 of the sliding bearing element 1 (e.g., due to the bearing oil pumped from the oil chamber 11) has sufficiently decreased, the sliding bearing element 1 is pushed away from the radial wall 35 of the bearing housing 9, thereby increasing the discharge volume (pump volume) of the oil chamber 11 again. During this process, bearing oil is drawn in due to negative pressure. However, the bearing oil should not be drawn in from the bearing clearance 7 via the oil supply passage 12. For this purpose, a reversing valve 16 is provided in this advantageous embodiment. As the hydraulic piston moves (discharges) into the oil chamber 11 along its stroke axis 38, the directional valve is switched so that bearing oil can flow out via the supply passage 12. As the hydraulic piston (in the opposite direction) moves outward from the oil chamber 11 along its stroke axis 38 (draws in), the directional valve 16 is switched so that bearing oil is drawn in from an external source (optionally the oil sump 15) via the suction line 37, thereby filling the oil chamber 11. For this purpose, the directional valve 16 is used, which (preferably adjusted by preload) closes in response to the applied pressure differential, or opens at the opposite pressure differential. In this embodiment, the check valve 39 prevents bearing oil from being drawn into the bearing clearance 7, but allows bearing oil to be supplied due to suction in the bearing clearance 7 or due to oil pressure from the hydraulic cylinder 10, so as to establish static pressure in the bearing clearance 7.

[0068] Using the sliding bearing element proposed here, the starting torque after the hydrodynamic bearing clearance has dried out can be significantly and reliably reduced.

[0069] Explanation of reference numerals in the attached figures 1. Sliding bearing components 2. Rotor shaft 3. Rotor shaft 4 Wind turbine generator sets 5. Bearing surface 6 Opposite surfaces 7. Bearing clearance / lubricating film 8 Circumferential bearing surface 9. Bearing housing 10 Hydraulic cylinders 11. Oil cavity 12 Oil supply channels 13 Zhou Xiang 14 Energy Storage Components 15 Oil tank 16. Reversing valve 17 Rolling element 18 needle rollers 19 Earth's Gravitational Field 20 Gravity 21 Maximum load section 22. Central Diagon 23 Circumferential angle range 24 Sliding bearings 25 Bearing housing 26 rotors 27 Rotor blades 28-inch wheels 29 towers 30 Vertical axis 31 Cabin 32 Generators 33 Yaw System 34 Gearbox 35. Radial wall of bearing housing 36 Opposite walls 37. Oil suction line 38 travel axis 39. Check valve.

Claims

1. A sliding bearing element (1) for a rotor shaft (2) having a rotor axis (3) in a wind turbine generator set (4), characterized in that, include: The bearing surface (5) is used to provide hydrodynamic support to the corresponding opposing surface (6) through the bearing clearance (7) therebetween, which is covered with a bearing oil film during operation; Circumferential bearing surface (8) for supporting the sliding bearing element (1) on the bearing seat (9) of the sliding bearing element (1); A hydraulic cylinder (10) is used to discharge bearing oil from the oil chamber (11); An oil supply channel (12) is located between the hydraulic cylinder (10) and the bearing surface (5), wherein bearing oil discharged from the oil chamber (11) can be supplied to the bearing clearance (7) via the oil supply channel (12), wherein the sliding bearing element (1) is supported with low friction in a circumferential (13) relative to the bearing seat (9) by means of its circumferential bearing surface (8).

2. The sliding bearing element (1) according to claim 1, wherein, The hydraulic cylinder (10) is driven by the movement of the sliding bearing element (1) relative to the bearing seat (9) in the circumferential direction (13), wherein, preferably, the hydraulic cylinder (10) is fixed to the bearing seat (9) in the circumferential direction (13).

3. The sliding bearing element (1) according to claim 1 or claim 2, wherein, The sliding bearing element (1) is preloaded along the circumferential direction (13) by means of at least one energy storage element (14).

4. The sliding bearing element (1) according to any one of the preceding claims, wherein, The bearing housing (9) includes an oil groove (15), or, in use, the bearing housing (9) and preferably also includes the circumferential bearing surface (8) arranged in the oil groove (15).

5. The sliding bearing element (1) according to any one of the preceding claims, wherein, The hydraulic cylinder (10) can be connected by means of a preferably passive directional valve (16) such that... During relative motion along the circumferential direction (13), bearing oil is correspondingly discharged from the oil chamber (11) by means of the hydraulic cylinder (10), and thus supplied to the bearing surface (5) via the oil supply channel (12), and When opposite relative movements occur along the circumferential direction (13), bearing oil is drawn into the oil chamber (11) by means of the hydraulic cylinder (10), wherein, preferably, bearing oil can be drawn from the oil groove (15), and particularly preferably, in conjunction with the sliding bearing element (1) according to claim 4.

6. The sliding bearing element (1) according to any one of the preceding claims, wherein, Rolling elements (17), preferably needle rollers (18), are arranged between the circumferential bearing surface (8) of the sliding bearing element (1) and the corresponding bearing housing (9), and / or the bearing housing (9) preferably operates wet in an oil groove (15), particularly preferably in accordance with the sliding bearing element (1) according to claim 4.

7. The sliding bearing element (1) according to any one of the preceding claims, wherein, A section (21) of the bearing surface (5) that is subjected to the greatest load by the gravity (20) of the supported rotor shaft (2) in the Earth's gravitational field (19) is formed, wherein the section (21) is arranged from the central angle line (22) parallel to the Earth's gravitational field (19) within a circumferential angle range (23) of ±30°, preferably ±15°, and particularly preferably ±5° above and / or below.

8. A sliding bearing (24) for the rotor shaft (2) of a wind turbine generator set (4), characterized in that, Includes at least the following components: A plurality of sliding bearing elements (1), each having a bearing surface (5) for supporting a corresponding opposing surface (6) through a bearing gap (7) therebetween which is covered by a bearing oil film during operation, wherein at least one of the sliding bearing elements (1) is configured according to any one of the preceding claims; Bearing housing (25); and Oil groove (15) and / or external source for providing bearing oil for the corresponding bearing clearance (7), wherein, preferably at least one of the bearing housings (9), and preferably also the associated circumferential bearing surface (8), is arranged in the oil groove (15).

9. A rotor (26) for a wind turbine generator set (4), characterized in that, Includes at least the following components: A rotor shaft (2) having a rotor axis (3); At least one sliding bearing (24) according to claim 8; Multiple rotor blades (27); Hub (28), wherein the rotor blades (27) are connected to the rotor shaft (2) via the hub (28), wherein the rotor shaft (2) is supported axially and / or radially by means of the hydrodynamic bearing surface (5) of the sliding bearing element (1) so as to be able to rotate about its rotor axis (3).

10. A wind turbine generator set (4), characterized in that, include Tower (29) with a vertical axis (30); A nacelle (31) with a generator (32), wherein the nacelle (31) is arranged on the tower (29) and is rotatable about the vertical axis (30) by means of a yaw system (33); and The rotor (26) according to claim 9 is rotatable about its rotor axis (3), wherein, The rotor shaft (2) is connected to the generator (32) in a torque-transmitting manner to convert its rotation about the rotor axis (3) into electric current.

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