Rotor blade bearing for underwater turbine

Abstract

The invention relates to a rotor blade bearing assembly (214) for an underwater turbine (1), wherein the rotor blade bearing assembly (214) is designed to rotationally support a rotor blade shaft (204) in a rotor hub housing (202), wherein the rotor blade shaft (204) has a sea-side end (207) which is designed to be connected to a rotor blade (4) for conjoint rotation, and a rotor-hub-side end (208) which is designed to be received by a rotor hub (2), and wherein the rotor blade bearing assembly (214) has the rotor blade shaft (204) and a first sea-side bearing unit (220) and a second rotor-hub-side bearing unit (230), wherein the first and the second bearing units (220; 230) are arranged at a distance W from one another, wherein the first and the second bearing units (220; 230) are designed as sliding bearings (225; 235) which each have an inner sliding surface (282; 292) and an outer sliding surface (281; 291), wherein the inner sliding surface (292) of the first sliding surface (225) is formed on the sea-side end (207) of the rotor blade shaft (204) and the inner sliding surface (282) of the second sliding bearing (235) is formed on the rotor-hub-side end (208) of the rotor blade shaft (204), and wherein the outer sliding surfaces (281; 291) of the first and the second sliding bearings (225; 235) are formed by a rotor hub housing portion (252; 262), wherein the rotor hub housing portion (252; 262) is formed as a hollow tube and has a sea-side end (255), on which the sliding layer (291) for the first sliding bearing (225) is formed, and a rotor-hub-side end (254), on which the sliding layer (281) for the second sliding bearing (235) is formed.

Description

[0001] Description

[0002] Rotor blade bearing for underwater turbine

[0003] Technical area

[0004] The present invention relates to a rotor blade bearing arrangement for an underwater turbine according to the preamble of claim 1, as well as a rotor blade arrangement with such a rotor blade bearing arrangement.

[0005] Technical background

[0006] The rotor blades of underwater turbines are typically attached to a rotor hub and can be mounted so they can rotate relative to the rotor hub. By rotating or pivoting the rotor blades, the drive power can be varied. Furthermore, the rotor blade pitch control rotates the rotor blades in such a way that no torque is transferred from the rotor blades to the rotor hub, allowing the turbine to come to a complete standstill. In some designs, the blade pitch control is used to adapt to changing water flow directions without having to rotate the entire underwater turbine.

[0007] However, the loads induced by the rotor blades, especially the high bending moment, lead to high stress on the rotor blade bearings, thus increasing the risk of damage to the rotor blade bearings, which in turn leads to long turbine downtimes. Furthermore, enormous forces act on the blade bearings due to water pressure.

[0008] It is therefore an object of the present invention to provide a rotor blade bearing assembly that can withstand high loads during its service life. Summary of the invention

[0009] This object is achieved by a rotor blade bearing arrangement according to patent claim 1, as well as a rotor hub according to patent claim 11.

[0010] The following presents a rotor blade bearing assembly for an underwater turbine, wherein the rotor blade bearing assembly is designed to rotatably support a rotor blade shaft in a rotor hub housing. The rotor blade shaft has a seaward end designed to be non-rotatably connected to a rotor blade, and a rotor hub end designed to be received by a rotor hub. The rotor blade bearing assembly comprises the rotor blade shaft, a first seaward bearing unit, and a second rotor hub bearing unit, wherein the first and second bearing units are arranged at a distance W from each other.

[0011] In order to provide a rotor blade bearing arrangement that can withstand the high loads and the large temperature differences, it is proposed that the first and the second bearing unit be designed as plain bearings, each having an inner sliding surface and an outer sliding surface, wherein the inner sliding surface of the first plain bearing is formed on the seaward end of the rotor blade shaft and the inner sliding surface of the second plain bearing is formed on the rotor hub-side end of the rotor blade shaft, and wherein the outer sliding surfaces of the first and the second plain bearing are formed by a rotor hub housing section, wherein the rotor hub housing section is shaped like a hollow tube and has a seaward end, on which the sliding layer for the first plain bearing is formed, and a rotor hub-side end, on which the sliding layer for the second plain bearing is formed.

[0012] The rotor hub itself preferably has a rotor hub housing that defines an interior space. In order to make the housing wall as thin as possible while still achieving high rigidity so that the underwater turbine can withstand high water pressures and rotor blade loads, the rotor hub housing can be further reinforced with stiffening ribs arranged in the interior space and reinforcing the structural stability of the rotor hub housing. Furthermore, as shown in a further advantageous embodiment, an assembly opening can be provided in the rotor hub housing, ensuring accessibility to the interior of the rotor hub. According to a preferred embodiment, the rotor hub housing has a hollow tube-shaped rotor hub housing section that is formed integrally with the rotor hub housing and is designed to be equipped with the outer sliding surfaces.

[0013] Alternatively, an embodiment is therefore proposed in which the rotor hub housing section is designed as a separate housing section from the rotor hub housing, which can be installed into a rotor hub housing together with the rotor blade bearing assembly and the rotor blade shaft. The rotor hub housing section is then attached to the rotor hub housing, for example, by means of fastening means, in particular screws. Alternatively, the rotor hub housing section can also be pressed into a correspondingly designed receptacle on the rotor hub housing.

[0014] As a result, the rotor blade bearing arrangement is designed as a module that is simply inserted into the rotor hub. The module preferably has pre-adjusted and / or pre-loaded bearing units and can be inserted into the rotor hub without further adjustment. As further preferred embodiments show, the rotor hub bearing module can also have a seawater seal and / or optionally further rotor blade shaft adjustment components (e.g. gears), etc., which are pre-assembled on the rotor blade bearing arrangement outside the rotor hub and installed as a unit in the rotor hub in a further assembly step. The advantage of the modular design is the simplified assembly of the bearing units, since this can take place outside the rotor hub housing with good accessibility and, as mentioned above, can be inserted into the rotor hub pre-adjusted and pre-loaded.The individual modules can also be replaced very quickly for service work and in the event of damage.

[0015] In order to achieve ideal tilting stiffness and thus high load-bearing capacity and at the same time compensate for the effects of thermal differences in the rotor blade bearing arrangement, it is proposed to arrange the first bearing unit and the second bearing unit at a bearing distance W such that the following applies to the bearing distance W: 0.8*D1 < W < 2*D1, preferably 1*D1 < W < 1.5*D1, where D1 indicates a diameter of the rotor blade shaft at the location of the first offshore bearing unit. According to a further preferred embodiment, the first bearing unit has a larger bearing diameter than the second bearing unit. Due to the smaller design of the second bearing unit, it can be manufactured more cost-effectively and the assembly of the first bearing unit onto the shaft is simplified.

[0016] According to a further preferred embodiment, at least one of the sliding surfaces has a sliding coating. Since both the rotor blade shaft and the rotor hub housing section are usually made of steel, bearing units designed as plain bearings would have a steel-on-steel sliding pairing that has relatively poor sliding properties. If, on the other hand, one of the sliding surfaces is coated with a sliding coating, this can significantly improve the sliding properties. A sliding coating with a plastic or a fiber composite material is particularly preferred, with the fiber composite material in particular comprising sliding fibers. The plastic or the fiber composite material can in particular comprise PTFE as the sliding material.

[0017] According to a further preferred embodiment, at least one plain bearing has radial sliding surfaces that are conically shaped. This makes it possible to provide a bearing arrangement with an O-arrangement, even with plain bearings. This makes it possible to achieve high flexural rigidity and improve the transmission of forces from the rotor shaft via the bearing unit into the rotor hub and / or a stiffening rib formed on the rotor hub. The idea of ​​a continuous force flow path is also implemented in the contour of possible internal stiffening ribs formed on the rotor hub housing. Here, too, force flow can be transmitted from the rotor blade shaft to the inner bearing and then, via the specially shaped stiffening ribs, to the outer contour of the hub. The theoretical force lines converge at the flange connection between the rotor hub and the main rotor shaft and are introduced into the surrounding structure (main rotor shaft).

[0018] Alternatively, at least one plain bearing has radial sliding surfaces that are cylindrical in shape. This type of plain bearing is particularly simple and effective to manufacture, since only cylindrical sliding surfaces with a single diameter need be formed on the rotor blade shaft or on the rotor hub housing section, and no care needs to be taken to ensure that the inclination angles of the sliding surfaces are precisely matched to one another. According to a further preferred embodiment, the rotor blade shaft has a stop step at its offshore end with a first offshore annular axial sliding surface that interacts with a first complementary annular axial sliding surface formed on the rotor hub housing section.

[0019] Alternatively or additionally, the rotor blade shaft can also have a stop step on its rotor hub-side end, which is designed to cooperate with a single-part or multi-part fastening ring, in particular a shaft nut with a thrust washer, in order to fasten the rotor blade shaft in the rotor hub housing section with a defined installation position, wherein the fastening ring has a second rotor hub-side annular axial sliding surface which cooperates with a second complementary annular axial sliding surface formed on the rotor hub housing section.

[0020] Both stop surfaces serve to secure the rotor blade shaft in a specific position relative to the rotor hub housing section, and thus in a specific location within the rotor hub. This allows for precise alignment of the components, which is necessary for connection to a drive mechanism.

[0021] It is also advantageous if the inner sliding surfaces of the first and second plain bearings are each formed by a first and a second sliding bushing, wherein the first sliding bushing is attached to the seaward end of the rotor blade shaft and the second sliding bushing is attached to the rotor hub end of the rotor blade shaft. This eliminates the need for a coating of the rotor blade shaft or the rotor hub housing section. The sliding coating is sometimes less robust than a sliding bushing and it is significantly more complex to provide such a coating. The sliding bushing itself is usually made of a fiber composite material and has fibers, in particular sliding fibers, that are embedded in a plastic matrix. In addition, the fiber composite can also have solid lubricant particles that support the sliding properties.Alternatively or additionally, the sliding bushing can also be made of a plastic that contains solid lubricant.

[0022] According to an advantageous embodiment, the sliding bushing is pressed onto the rotor blade shaft, wherein the rotor shaft and the sliding bushing are designed such that an overlap is provided between the outer diameter of the rotor blade shaft and the inner diameter of the sliding bushing. This ensures that the sliding bushing sits securely on the rotor blade shaft. The inner first and second sliding surfaces are represented by the outer circumferential surfaces of the sliding bushings. The two outer sliding surfaces, which can be brought into sliding contact with the inner sliding surfaces, are formed by the rotor hub housing section. Alternatively, it is also possible to press the first and second sliding bushing into the rotor hub housing section, such that the outer first and second sliding surfaces are formed by an inner circumferential surface of the sliding bushings and the inner first and second sliding surfaces are formed by the outer diameter of the rotor blade shaft.It is also conceivable that one of the two sliding bushings is pressed onto the rotor blade shaft and the other sliding bushing is pressed into the rotor hub housing section.

[0023] The axial sliding surfaces can also be coated with a sliding coating, as described above. However, it is preferred to provide a sliding disk instead of the coating for the axial sliding surfaces, which provides the axial sliding surface. A particularly preferred embodiment is one in which the radial and axial sliding surfaces are provided via a sliding bushing, with a flange then formed on the sliding bushing, which provides the axial sliding surface. Such sliding bushings can be easily mounted on the rotor shaft.

[0024] According to a further preferred embodiment, the rotor blade bearing assembly further comprises at least one seawater seal assembly with at least one sealing lip, wherein the seawater seal assembly is designed to provide a seal between the rotor hub housing section and the rotor blade shaft. Preferably, the seawater seal assembly is designed to be attachable to the rotor hub housing section, and the at least one sealing lip abuts the rotor blade shaft. Preferably, the seawater seal assembly is a redundant lip seal for long maintenance intervals and can include a relubrication function and a condition monitoring system.

[0025] This type of attachment allows the seawater seal to be easily replaced even when the underwater turbine is fully assembled. Furthermore, the design of the rotor blade bearing arrangement according to the aforementioned relationship between bearing spacing and rotor blade shaft diameter allows the rotor blade shaft to have a smaller overall diameter, which in turn also leads to a smaller diameter of the dynamic seawater seal. This, in turn, allows for the relative movement of the seal to be reduced, which in turn reduces wear on the seawater seal.

[0026] As mentioned above, the rotor blade bearing assembly is preferably designed as a module and can advantageously include, in addition to the rotor blade shaft and bearing units, the rotor hub housing section and the seawater seal. This allows the entire assembly to be easily replaced.

[0027] According to a further preferred embodiment, the rotor blade shaft, regardless of whether it is present as a module or not, can have at least one drive component at its first rotor-hub end, which is designed to cooperate with a central drive for rotating the rotor blade shaft. Since the rotor shaft extends relatively far into the interior of the rotor hub due to the bearing arrangement discussed above, the rotor shaft is particularly well suited for central adjustment drives. In this case, all rotor blades are connected via a mechanism and centrally controlled via an actuator (e.g., electric motor, hydraulic cylinder). In other words, the rotor blades are adjusted together, rather than individually.

[0028] According to another preferred embodiment, the drive components are bevel gears, with the adjustment drive preferably driven by an electric geared motor or a hydraulic motor, and torque distribution via a central bevel gear. Alternatively, the drive component can also be a push rod connected to the rotor blade shafts via a connecting rod-Z crankshaft mechanism. The push rod itself is axially movable by means of a linear drive and ensures adjustment of the rotor blade shafts.

[0029] According to a further preferred embodiment, the first and / or second plain bearing is fluid-lubricated, wherein the fluid is preferably a corrosion-inhibiting fluid, in particular deionized and / or demineralized water. Fluid lubrication of the plain bearings enables a further reduction of friction on the sliding surfaces and can simultaneously provide cooling. A special form of fluid lubrication can also be provided, namely lubrication with water. For example, seawater can also be used. If seawater is used, a complex seawater seal can be dispensed with, since it is precisely desired that seawater penetrates the space between the rotor blade shaft and the rotor hub housing section in order to lubricate the plain bearings arranged there.

[0030] However, since seawater is relatively corrosive, it is preferable to use a corrosion-inhibiting fluid for fluid lubrication. For environmental reasons, deionized and / or demineralized water is particularly suitable.

[0031] However, to minimize fluid transfer into the surrounding seawater and also to reduce the buoyancy of the underwater turbine, it is still preferable to flood the entire rotor hub housing with the lubricating fluid. The lubricating fluid should have a density similar to water.

[0032] A further aspect of the present application is therefore directed to a rotor hub assembly for an underwater turbine having a rotor hub housing designed to be non-rotatably connected to a main rotor shaft for driving a generator, and designed to accommodate and rotatably support at least one rotor blade shaft, wherein a rotor blade bearing assembly as described above is used to support the rotor blade shaft. The rotor hub assembly, in turn, is typically non-rotatably connected to a main rotor shaft, which in turn drives a generator to generate power. It is particularly preferred if the interior of the rotor hub housing is flooded with a fluid that simultaneously serves as a lubricant for the plain bearings.

[0033] It is particularly preferred if the fluid has a density similar to that of water, or if the fluid is water, in particular sea water, but preferably deionized and demineralized water.

[0034] While such a design could completely eliminate the need for seawater seals, it is advantageous to install a relatively simple sealing arrangement between the rotor blade shaft and the rotor hub housing. Such a sealing arrangement can be a sealing arrangement that merely performs a dirt-retaining function to protect the plain bearings and drive components from dirt particles. Alternatively or additionally, the sealing arrangement can also be a sealing arrangement with a pressure-equalizing function, which ensures that pressure equalization with the environment can occur in the event of negative or positive pressure in the rotor hub housing. This minimizes wear on the seal, as it does not have to work against pressure.

[0035] According to a further preferred embodiment, the rotor hub assembly comprises at least two opposing rotor blades that are attached to rotor blade shafts, which in turn are each supported and attachable by means of the rotor blade bearing assembly. As mentioned above, the rotor blade shafts each have a first seaward end that can be attached to the rotor blade in a rotationally fixed manner, and a second rotor hub-side end that projects into an interior of the rotor hub. Furthermore, the opposing rotor blade shafts are arranged in the rotor hub with the aid of the rotor blade bearing assembly such that a diameter X of a circle described by the rotor hub-side ends of the rotor blade shafts and a diameter Y of a circle described by the seaward ends of the rotor blade shafts satisfy the following relationship:

[0036] X:Y ~ 6:1.

[0037] In a preferred embodiment in which two opposing rotor shafts are used, this means that a distance X between the rotor hub-side ends of the two opposing rotor blade shafts and the distance Y between the sea-side ends of the two opposing rotor blade shafts satisfy the said relation.

[0038] As mentioned above, the rotor blade shafts extend deep into the interior of the rotor hub and enable a fully integrated, centralized rotor blade pitch system, combining compact design with cost efficiency.

[0039] According to a further preferred embodiment, a so-called spinner is also arranged on the rotor hub, which is designed to improve the flow dynamics of the turbine. A spinner is a streamlined fairing that is attached to the center of the rotor hub. Spinners make the turbine more streamlined overall, thereby reducing flow resistance and smoothing the flow path. The spinner can also be designed to accommodate drive components of the rotor blade adjustment system, for example the geared motor for the bevel gear drive or the linear drive for the. According to a further preferred embodiment, the rotor hub arrangement and / or the underwater turbine as a whole is also protected against corrosion by providing a corrosion-protective coating and / or at least one sacrificial anode.

[0040] Further advantages and advantageous embodiments are set forth in the description, the drawings, and the claims. In particular, the combinations of features set forth in the description and the drawings are purely exemplary, so the features may also be present individually or in other combinations.

[0041] Short character description

[0042] The invention will be described in more detail below with reference to exemplary embodiments illustrated in the drawings. The exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of the invention. This scope is defined solely by the appended claims.

[0043] They show:

[0044] Fig. 1 to Fig. 23: schematic sectional views of various different preferred embodiments of an underwater turbine.

[0045] Detailed description of the invention

[0046] In the following, identical or functionally equivalent elements are identified by the same reference symbols.

[0047] Figure 1 shows a schematic sectional view of an underwater turbine 1. The underwater turbine 1 comprises as its main components a rotor hub 2, which is designed to mount and support rotor blades 4, and a main rotor shaft 6 which is rigidly connected to the rotor hub 2 and extends into a nacelle 8 in which a generator 10 for generating electricity is accommodated. The main rotor shaft 6 can be fastened to the rotor hub 2, for example, by means of fastening means, in particular screws 5. A water current flows against the rotor blades 4, thereby causing the rotor hub 2 to rotate. The rotationally fixed connection of the rotor hub 2 to the main rotor shaft 6, in turn, drives a rotor 12 of the generator 10, which is rotationally fixedly connected to the main rotor shaft 6.The rotor 12 can be attached directly to the main rotor shaft 6, but it is also possible for a gearbox (not shown) to be arranged between the main rotor shaft 6 and the generator 10, which converts the slow rotation of the main rotor shaft 6 into a fast rotation for power generation. The main rotor shaft 4, in turn, is rotatably mounted in the nacelle 8 by means of bearing units 14, 16. The bearing units 14, 16 are particularly designed to accommodate axial and radial loads. For example, the main rotor shaft 6 can be mounted on axial and radial bearing units.

[0048] The rotor blades 4 are preferably also mounted so that they can be adapted to the respective flow direction without having to rotate the entire nacelle 8. Furthermore, the adjustment of the rotor blades 4 also allows the rotor blades 4 to be rotated into the so-called feathered position, in which the flow does not cause the rotor hub 2 to rotate. This allows the underwater turbine 1 to be shut down entirely.

[0049] The rotor blades 4 themselves are typically arranged symmetrically to one another and, in the case of two rotor blades 4-1, 4-2, are arranged directly opposite one another. With more than two rotor blades, such as three or four rotor blades 4, these can be arranged at a distance of 120° or 90° from one another.

[0050] In the embodiments shown in Figures 1 to 23, a two-bladed rotor is shown which has two opposing rotor blades 4-1; 4-2.

[0051] Furthermore, Figures 2 to 23 show various details and embodiments of the underwater turbine 1. In particular, Figures 2 to 5 show various basic designs of a rotor hub assembly 200. The rotor hub assembly 200 typically comprises a rotor hub housing 202 into which a rotor blade shaft 204 is inserted.

[0052] The rotor blade shaft 204, in turn, is designed to be connected to the actual rotor blades 4 (see Fig. 1) and can be constructed in one or more parts. It is also possible for the rotor blade shaft to be designed as a shaft stub. The two-part design into rotor blade 4 and rotor blade shaft 204 allows the rotor hub assembly 200 to be transported pre-assembled, with the rotor blades only being connected to the rotor hub assembly 200, and more precisely to the rotor blade shaft 204, at the site of use. In some embodiments, it is even possible to mount the rotor blades on the rotor blade shaft underwater. For this purpose, it is particularly advantageous if a rotor hub interior 210 is sealed off from the water into which the underwater turbine is installed.

[0053] In the two-bladed rotor shown in Figs. 2 to 5, the rotor blade shafts 204-1, 204-2 each have a seaward end 207 and a rotor hub-side end 208. The seaward end 206 is designed to be connected to the actual rotor blades 4, while the rotor hub-side end 208 projects into an interior space 210 of the rotor hub assembly 200 and is designed to be connected to a preferably central rotor blade twisting device 300. To enable twisting of the rotor blades or the rotor blade hubs 204, the rotor blade shafts 204 are rotatably mounted relative to the housing 202 of the rotor hub 2 by means of a rotor blade bearing assembly 214.

[0054] The rotor blade shafts 204 themselves define a length L of the rotor blade shaft 204 between their seawater-side end 207 and their rotor hub-side end 208. The two rotor hub-side ends 208-1 and 208-2 and the two seawater-side ends 207-1, 207-2 are in turn spaced apart by a distance X and Y, respectively. If more than two rotor blades are present, the rotor hub-side ends 207 and the seawater-side ends 208 each lie on a circle with a diameter X and Y, respectively.

[0055] The rotor blade bearing assembly 214 further comprises a first offshore bearing unit 220 and a second rotor hub-side bearing unit 230. The bearing units 220 and 230 can be designed as rolling bearing units 221, 231, as shown in Figures 2 to 5. However, it is also possible, as shown in Figures 6 to 8, to design the bearing units 214 as plain bearing units 225; 235.

[0056] If the bearing units 220; 230 are designed as rolling bearings 221; 231, they each have an inner ring 222; 232 and an outer ring 223; 233, which define a bearing interior between them in which rolling elements 224; 234 are arranged. The rolling elements 224; 234 can optionally be guided in a rolling bearing cage (not shown).

[0057] If the bearing units 220; 230 are designed as plain bearings 225; 235, plain bearing bushes 226; 236 can be provided, which ensure particularly good plain bearing support. The bearing inner rings 222; 232, more precisely an inner bore 227, 237 of the bearing inner rings 222; 232, or the plain bearing bushes 226; 236, each have an inner diameter dli, d2i that is dimensioned such that the bearing inner rings 222, 232 or the plain bearing bushes 226; 236 can be connected in a rotationally fixed manner to the respective rotor blade shaft 204. The inner diameters dli, d2i are usually dimensioned such that they overlap with an outer diameter of the rotor blade shaft 204, so that the bearing inner rings 222, 232 or the plain bearing bushes 226; 236 can be press-fitted to the rotor blade shaft 204.

[0058] The bearing outer rings 223, 233 are non-rotatably mounted on a rotor hub housing section 252; 262. The rotor hub housing section 252 can be designed as an integral component of the rotor hub housing 202 (see, for example, Figs. 2 and 3), but it is also possible for the rotor hub housing section 262 to be a separate housing section that is connected to the rotor hub housing by means of fastening means 264 (see, for example, Figs. 4 and 5).

[0059] Of course, it is equally possible to connect the plain bearing bushes 226; 236 to the rotor hub housing section 252; 262 in a rotationally fixed manner, preferably by pressing them into the rotor hub housing section 252; 262.

[0060] For the rotationally fixed connection, an inner diameter of the rotor hub housing from section 252, 262 is usually dimensioned such that it has an overlap with an outer diameter of the bearing outer rings 223, 233 or the plain bearing bushes 226; 236, so that the bearing outer rings 223, 233 or the plain bearing bushes 226; 236 can be fastened with a press fit in the rotor hub housing section 252; 262.

[0061] Furthermore, the rotor hub assembly 200 has a preferably dynamic seawater sealing assembly 240 which is designed to seal a gap 242 between the rotor blade shaft 204 and the housing 202 in order to prevent water from entering the interior of the rotor hub 2.

[0062] In order to achieve ideal tilting stiffness and thus high load-bearing capacity, while simultaneously compensating for the effects of thermal differences in the rotor blade bearing assembly 214, the first bearing unit 220 and the second bearing unit 230 are spaced apart from one another by a specific bearing distance W, each measured from the center of the bearing unit (see Figs. 2, 3 and 6, 7). The bearing distance W is set in relation to the inner diameter dli of the inner bore 227 of the offshore bearing unit 220, so that 0.8*dli < W < 2*dli, preferably l*dli < W < l.5*dli.

[0063] This also makes it possible to compensate for the possible thermal growth of the rotor blade shaft 204, as well as the ring growth of the warm bearing inner rings 222 compared to the cooler bearing outer rings 223, in rolling bearings 221; 231, especially in tapered roller bearings, which ensures jam-free operation of the bearing units 220, 230. Furthermore, this also makes it possible to counteract a loss of preload in the bearing arrangement—provided the bearing units 220, 230 are installed with a preload, as is common, for example, with tapered roller bearings.

[0064] The special spaced arrangement of the bearing units 220, 230 further allows the rotor blade shaft 204 to be longer and thus extend further into the interior 210 of the rotor hub 2. Furthermore, the diameter of the rotor blade shaft 204 can be reduced, as the forces exerted by the rotor blade 4 on the rotor blade shaft 204 and on the bearings 220, 230 are distributed over a longer distance. The smaller shaft diameter, in turn, allows the seawater-side seal assemblies 240, which seal the rotor hub, to also have a smaller diameter. This reduces the relative movement of the seals, which contributes to the overall slower wear of the seals.

[0065] It is particularly preferred that a length L of the rotor blade shaft 204 is adapted such that a distance X of the rotor hub-side ends 208-1, 208-2 of two opposing rotor blade shafts 204-1, 204-2 and a distance of the seawater-side ends 207-1, 207-2 of the opposing rotor blade shafts 204-1, 204-2 (or alternatively the diameters X, Y of the circles described by the corresponding ends 208 and 207, respectively) satisfy the following relationship: X: Y ≡ 6: 1.

[0066] This allows for a short distance between the rotor blade shafts 204-1, 204-2 with a relatively large rotor blade pitch. Fig. 9 further shows that the rotor hub housing 202 has rib structures 250 that structurally reinforce the housing 202 and enable the provision of a relatively thin-walled housing 202 that can nevertheless withstand high loads, in particular high water pressure at greater depths.

[0067] As can be seen in particular from Figs. 2 to 6, the bearing units are arranged such that they form an O-arrangement, wherein the O-arrangement is designed such that a force flow can be absorbed by the rib structures 250 arranged in the housing 202 and transmitted to the rotor main shaft 6. This is possible both with rolling bearing units, in particular tapered roller bearings, and with a corresponding plain bearing design (see Fig. 6).

[0068] Furthermore, Figures 2, 3 and 6 to 8 show that the rotor blade shaft 204 can be inserted into the rotor hub housing 202 together with the bearing units 220 and 230, wherein the rotor hub housing 202 in this embodiment has the rotor hub housing section 252 which is formed integrally with the rotor hub housing and extends inwardly in a tubular manner and which can be designed as a bearing seat for the outer rings 223; 233 or as a sliding surface or seat for the plain bearing bushes 226; 236.

[0069] Alternatively, however, the rotor blade shaft 204 and the bearing units 220 and 230 can also be designed as a module 260, which can be inserted in its entirety into the rotor hub housing 202 (see in particular Figures 4 and 5). For this purpose, the module 260 further comprises the separate rotor hub housing section 262, which is also tubular and is referred to below as the module housing section 262 and is designed as a bearing seat for the outer rings 223; 233 or as a sliding surface or seat for the plain bearing bushes 226; 236 for the bearing units 220 and 230, respectively. The tubular module housing section 262 can be fastened to the housing 202 of the rotor hub assembly by means of fastening elements 264. The design as module 260 has the advantage that the bearing units 220 and 230 can be provided fully assembled and, if necessary, preloaded and only need to be inserted into the housing.Furthermore, in this case, the seawater seal 240 can already be attached to the module 260, so that the assembly steps for assembling the module 260 into the rotor hub housing 202 can be significantly simplified. Tapered roller bearings are particularly suitable as bearing units 220; 230, since they can absorb high external loads, especially bending moments, in an O-arrangement and enable a continuous force introduction into the main rotor shaft 6. This also allows the bearings to be dimensioned smaller overall.

[0070] Alternatively, Figures 6 to 8 show the above-mentioned plain bearing of the rotor blade shaft 204. Figures 6 to 8 show a rotor shaft 204 that is inserted into the housing 202 of the rotor hub 2, with a sliding pairing being formed between the tubular housing section 252 of the raw hub housing 202, or the module housing section 262, and the rotor blade shaft 204, which pairing each forms a first offshore sliding surface pairing 280 and a rotor hub-side sliding surface pairing 290. Figures 6 to 8 only show the integrated design with a housing section 252 and not the modular design. However, the following statements apply analogously.

[0071] To form the rotor hub-side sliding surface pairing 280 or the seawater-side sliding surface pairing 290 with outer sliding surfaces 281; 291 and inner sliding surfaces 282, 292, the housing section 252 has, in particular, a first rotor hub-side section 254 and a second seaside section 255, which are designed as outer sliding surfaces 281, 291. In this exemplary embodiment, the inner sliding surfaces 282; 292 are formed by the plain bearing bushes 226; 236. The inner and outer sliding surfaces 281, 291, 282, 292 are designed as radial sliding surfaces that serve to radially support the rotor blade shaft 204 with respect to the rotor hub housing section 252.

[0072] Analogously, an outer surface 203 of the rotor blade shaft 204 can serve as counter sliding surfaces. Fig. 8 illustrates such an embodiment in which the plain bearing bushes 226, 236 are pressed into the rotor hub housing section 252 and the rotor blade shaft 204 has a first surface section 203-1 and a second surface section 203-2, which are designed as inner sliding surfaces 282, 292.

[0073] Additionally, axial sliding surfaces 283, 293 (outer); 284, 294 (inner) can also be provided. The axial sliding surfaces 283, 293; 284, 294 enable, for example, the rotor blade shaft 204 to be equipped with a stop surface 206 at its offshore end 207, which interacts with a corresponding counter-stop surface 256 on the rotor hub housing section 252 to define a defined insertion position of the rotor blade shaft 204 in the rotor hub housing 202. The outer axial sliding surface 293 is then formed on the stop surface 206, while the inner axial sliding surface 294 is formed on the counter-stop surface 256 of the rotor hub housing section 252.

[0074] Analogously, an axial plain bearing can also be formed on the rotor hub-side end 208 of the rotor blade shaft 204 or the rotor hub-side end 254 of the rotor hub housing section 252. In the illustrated embodiments in Figs. 7 and 8, a stop surface 257 is also formed on the rotor hub side of the rotor hub housing section 252, which is designed as an outer axial sliding surface 283 for the rotor hub-side plain bearing 235. A shaft nut 246, which is equipped with an inner sliding surface 284, can cooperate with this sliding surface 283, for example. The shaft nut 246 serves, for example, to secure the rotor blade shaft 204 in the rotor hub housing 202.

[0075] Instead of the plain bearing bushings 226; 236 shown in the figures, the corresponding sliding surfaces 281, 291; 282, 292; 283; 293; 284; 294 can also be provided with a sliding coating, for example made of a fiber composite material, to avoid a steel-on-steel sliding pair. The plain bearing bushing 226; 236 can also be made of a fiber composite material. Such a fiber composite material preferably comprises a sliding fiber and / or a plastic matrix made of a lubricious material, such as PTFE.

[0076] In the embodiments shown in Figures 6 and 7, plain bearing bushes 226; 236 are used, which are non-rotatably attached to the rotor blade shaft 204, while in Figure 8 the plain bearing bushes are pressed into the rotor hub housing section 252.

[0077] Fig. 6 shows an embodiment in which, analogous to an O-arrangement of a tapered roller bearing, conical plain bearing bushes are used, which are also arranged in an O-arrangement. The rotor blade shaft 204 can have a conical plain bearing bush receiving surface (or sliding surface) 205, but it is also possible for an additional bearing element, such as an inner ring 286, to be arranged on the rotor blade shaft 204, which carries the conical plain bearing bush 236 or serves as a sliding surface for the conical plain bearing bush. The angle of attack of the conical plain bearing arrangement is again selected such that force can be introduced into the reinforcing ribs 250. The plain bearing bushes 226, 236 can also form cylindrical sliding surfaces, as shown in Fig. 7 and Fig. 8. Furthermore, Fig.7 and 8 show that the plain bearing bushes 226; 236 have a cylindrical sleeve portion 228; 238 serving as a radial bearing, with the aid of which the radial sliding surfaces 281, 291; 282, 292 are formed, and a flange portion 229, 239 serving as an axial bearing, with the aid of which the axial sliding surfaces 283, 293, 284, 294 are formed.

[0078] According to a further preferred embodiment, the plain bearing is also fluid-lubricated, in particular water-lubricated. For this purpose, the entire interior 210 of the rotor hub 2 can preferably be flooded with a fluid, so that not only the plain bearing bushes 226; 236, as shown in Figures 6 to 8, are lubricated with the fluid, but also other bearing units arranged in the rotor hub interior 210. The fluid can be water, in particular deionized and demineralized water, which, compared to seawater, has corrosion-reducing properties, or a fluid that has a density similar to water.

[0079] If water is used as the fluid, the seawater seal 240, which completely seals the gap 242 between the rotor housing 202 and the rotor blade shaft 204, can be omitted and only a simple seal 244 with a dirt retention function can be provided (see Fig. 7). Since the same pressure prevails both in the rotor housing interior 210 and in the surrounding medium, this seal 244 is not subjected to significant stress and merely retains dirt particles that could endanger the plain bearing pairing between the rotor housing 202 and the rotor blade shaft 204.

[0080] With such a fluid-lubricated bearing, sealing devices on the rotor hub-side end 208 of the rotor blade shaft 204 can also be dispensed with. Typically, an interior space of both the rotor blade shaft 204 and the rotor blade 4 is filled with water to prevent floating or buoyancy due to trapped air. As a result, the rotor blade shaft 204, as shown in particular in Figure 8, can be designed entirely as a hollow shaft, which is closed, for example, only by means of crank pulleys. Of course, it is also possible to design the rotor blade shaft 204 not entirely as a hollow shaft, as shown in Figures 6 and 7. Furthermore, the embodiments of Figures 2, 4 and 10 to 13 show that a bevel gear drive 310 is used as the central rotor blade rotating device 300 for adjusting the rotor blade shafts 204.For adjustment using a bevel gear drive 310, in the illustrated embodiments, a bevel gear 312-1 or 312-2 is attached to the rotor blade shaft 204 at the rotor hub-side end 208, which mesh with a central bevel gear 314. The central bevel gear 314 is in turn driven by a drive unit 316 or an electric motor and enables adjustment of the rotor blades by 360°. This solution is possible both with a modular design as shown in Figure 4 and with installation of the rotor blade shaft in the housing 202 itself (see Figures 2 and 10 to 13). The electric motor 316 can be designed compactly and arranged in the interior 210 and rotor hub 2 (see Figure 11) or in the main rotor shaft 6 designed as a hollow shaft (see Figure 12).

[0081] In the embodiment shown in Fig. 11, the drive motor 316 is compact and can therefore transmit the required torque directly. To provide the required torque to the rotor blade shaft 204, a gearbox 317 is provided between the bevel gear 312 and the rotor blade shaft 204 in the illustrated embodiment. The bevel gears 312-1, 312-2 are coupled to a gearbox input shaft 318. The speed is reduced and the torque increased via a gear ratio stage 319. The rotor blade shaft is non-rotatably mounted on the gearbox output side. The gearbox 317 is preferably designed with one or more planetary stages.

[0082] However, if the electric motor 316 is structurally relatively bulky, it may further be provided to provide an additional housing section 272 on the housing 202 of the rotor hub assembly 200, which is designed to accommodate the electric motor 316. In order not to impair the streamlining of the underwater turbine 1 in this case or to improve the flow to the rotor blades 4, a so-called spinner 274 may be attached to the housing section 272 (see in particular Figs. 2, 10 and 13).

[0083] Instead of an electric motor 316, the housing section 272 can of course also accommodate other types of drive units.

[0084] Furthermore, in particular, Figs. 4, 10, and 12 show that the main rotor shaft 6 is hollow and that cables 270 can be passed through it, which can be used to control the electric motor 316. Furthermore, Figs. 2, 4, and 10 to 13 show that the rotor blade shafts 204 can also have a bore 209 through which cables 270 can be passed, for example, to supply current to sensors (not shown) and to transmit signals that detect, for example, a deformation of the rotor blades 4 and / or a load acting on the rotor blades 4.

[0085] Since the rotor blades do not need to constantly move to new positions and it is sometimes useful to move the rotor blades into a so-called feathered position and hold them there, in which no torque can be transmitted from the water flow to the rotor blades, e.g., for maintenance purposes, it is also useful to provide a locking device 320 that fixes the rotor blades in a specific position. For this purpose, as shown in Figure 13, a locking device 320 that is non-rotatably attached to the rotor hub housing 202 can be provided. This locking device also has a bevel gear 322 that can be engaged with the bevel gears 312-1 and 312-2 by means of actuating elements 324 to prevent them from rotating further. If the locking bevel gear 322 is engaged with the bevel gears 312, the drive unit 316 can be de-energized and does not have to constantly hold the bevel gears 312 and thus the respective rotor blade shafts 204 in their position.This is also advantageous in terms of energy efficiency. Furthermore, the locking device 320 can be designed such that, in the event of a power failure, the locking bevel gear 322 only engages with the bevel gears 312 when the rotor blades 4 move into the feathered position due to the water flow and because no force is rotating the rotor blades into the water flow. The locking device 320 then ensures that further rotation of the rotor blades 4 is not possible.

[0086] Instead of a bevel gear arrangement, a push rod arrangement 330 can also be used as the central rotor blade twisting device 300.

[0087] Figures 3, 5, and 14 to 23 show, as an alternative central rotor blade twisting device 300, the push rod assembly 330 with a push rod 332 that is axially movable and interacts with the rotor blade shaft 204 to rotate it. The push rod 332 typically has a first rotor hub-side end 334 and a second opposite end 336, and extends through a bore 60 in the main rotor shaft 6. In the case of a flooded rotor hub, this bore can be sealed by means of a seal 374 (see Fig. 17). The push rod 332 is moved axially by means of a linear drive 400, wherein the linear drive 400 can interact directly with the push rod (see Figs. 14 and 15), but can also act indirectly on the push rod as a separate component (see Fig. 16).

[0088] As can be seen in particular from Figures 17 and 18, the push rod 332 is connected to the rotor hub end 208 of the rotor blade shaft 204 by means of a connecting device 340.

[0089] The connecting device 340 has one connecting rod 342 per rotor blade shaft 204. Each connecting rod 342 comprises a connecting rod 344, at the ends 346; 348 of which an eye 350; 352 is formed. The eyes 350; 352 serve as plain bearings for bolts 354; 356, which ensure a rotatable attachment of the connecting rod 342.

[0090] The connecting rod 342 is rotatably connected at its first end 346 by means of the bolts 354 to a connecting rod-push rod connecting element, in particular a connecting rod holder 358, which in turn is non-rotatably attached to the push rod 332.

[0091] On the second side 348, the respective connecting rods 342-1, 342-2 are rotatably attached to connecting rod-rotor blade shaft connecting elements, for example crank disks 360-1, 360-2, by means of bolts 356, wherein each crank disk 360 is in turn connected in a rotationally fixed manner to the corresponding rotor blade shaft 204, wherein, for example, fastening elements 362 can be used.

[0092] The sectional view of Fig. 8 shows in particular a further embodiment of the connecting rod-rotor blade shaft connection, wherein here also a crank disk 360 is used, which is fastened to the rotor blade shaft 204 with fastening elements 362. Furthermore, it can be seen from this exemplary embodiment that the connecting rods 342-1, 342-2 each have a spherical bearing unit 380-1, 380-2 in their second connecting rod eyes 352, which in the illustrated exemplary embodiment is designed as a spherical plain bearing. The spherical bearing unit 380 in turn has an outer ring 381 and an inner ring 382, ​​which are arranged slidingly against one another. The spherical plain bearing 380 can, for example, be pressed into the connecting rod eye 352 with the aid of a bolt 384 that carries the bearing and can be connected to the crank disk 360. Furthermore, Fig.8 shows that an O-ring 390 can be inserted as a seal between the crank disk 360 and the rotor blade shaft 204, which, for example, seals a flooded rotor blade shaft against a dry rotor hub interior.

[0093] If the push rod is moved axially, as shown in Figures 18, A, B, and C, the rotor blade shaft 204 can be rotated from a first maximum position I (see Figure 11A) to a second maximum position II (see Figure 11C). In the center position shown in Figure 11B, the connecting rod 342 is at its maximum angle. Furthermore, it is preferred that the first maximum position I corresponds to a feathered position, and the second maximum position II corresponds to a maximum force absorption position of the rotor blades 4 in the water flow.

[0094] Furthermore, it is preferred that the push rod 332 is pre-tensioned into the flag position I, so that only when the push rod 332 is actively moved is the rotor blade 4 moved into a position in which the water flow exerts a torque on the rotor blades 4.

[0095] The push rod 332 can, as shown in Figures 15 to 23, be accommodated in the rotor main shaft 6, which is designed as a hollow shaft. However, it is also possible for the push rod 332, as shown in Figure 14, to be arranged on a side of the rotor hub 2 opposite the rotor main shaft 6. In this case, analogous to the bevel gear drive of Figures 2 and 3, a housing 272 is provided that surrounds the push rod mechanism 330, and the housing 272 can in turn be equipped with a spinner 274 as a flow optimization element.

[0096] If the push rod 332 extends through the rotor main shaft 6, which is designed as a hollow shaft, as shown in Figures 3, 5 and 15 to 23, a linear bearing unit 370 in the form of a bearing bush 372 is also arranged on the rotor main shaft 6, which supports the push rod 332 with respect to the rotor main shaft 6 and ensures axial mobility of the push rod 332. The push rod 332 itself, as mentioned above, has a rotor hub-side end 334 and a second end, which in Figures 3, 5 and 15 to 23 is designed as a nacelle-side end 336. The second end 336 can extend through the entire rotor shaft 6, but it is also possible, as shown in particular in Figure 15, for the nacelle-side end 336 of the push rod 332 to also be received in the rotor main shaft 6. In order to move the push rod 332 axially, as mentioned above, the second end 336 of the push rod 332 is subjected to axial force directly or indirectly by means of a linear drive 400.In the embodiments illustrated in Figures 14 and 15, the push rod 332 is designed at its second end 336 as a hydraulic piston 402, which is received in a hydraulic cylinder 404. In Figure 14, the hydraulic cylinder 404 is received in the housing section 272, while in the embodiment of Figure 15, the hydraulic cylinder is inserted into the rotor main shaft 6.

[0097] Of course, in addition to the hydraulic linear drive 400 shown here, any other linear drive 400 can be used, for example a pneumatic linear drive or a worm drive.

[0098] The push rod 332, designed as a piston, has a flange 405 at its second end, which is sealingly guided in the piston housing 404 and thus forms a first working chamber 406 and a second working chamber 408. The first working chamber 406 and the second working chamber 408 can each be pressurized with hydraulic fluid in order to move the push rod piston 402 and thus the push rod 332 from the first position I to the second position II. A pump unit 410 is also provided for the application of hydraulic fluid, which, in the embodiment shown in Fig. 15, is non-rotatably received in the nacelle 8 and is rotatably attached to the hydraulic cylinder 404 via a rotary union 412. Such rotary unions 412 are known in the prior art and will therefore not be described further.

[0099] The rotary union 412 is in turn rotationally fixed to the nacelle 8 by means of a fastening element 414. Furthermore, control units 416 are accommodated stationary in the nacelle 8. Figure 15 shows that a cable bushing is provided for the cable 270, which runs from the nacelle 8 or the control units 416 through the main rotor shaft 6 and extends into the rotor blades 4, for example, to supply current to sensors and / or transmit signals. This cable 270 is also connected to the stationary elements 416; 410 in the nacelle 8 via a rotary union 419 at the end of the rotor hub 6.

[0100] Figures 16 to 23 show embodiments in which the gondola-side end 336 of the push rod 332 extends into the gondola interior 802. In these illustrated embodiments, too, the push rod 332 is moved from the first I to the second II position by means of a hydraulic linear drive 400. In contrast to the embodiment shown in Figure 12, however, in the embodiments shown in Figures 16 to 23, the push rod 332 or its gondola-side end 336 is not directly pressurized with a hydraulic fluid, but the gondola-side end 336 of the push rod 332 is moved from the first I to the second II position by means of a separate linear drive unit 400, which is non-rotatably fastened in the gondola 8.However, since the push rod 332 rotates with the rotor hub 2 in the same way as the rotor main shaft 6, but the linear drive 400 is stationary, a rotational decoupling must be provided between the push rod 332 and the linear drive 400.

[0101] The figures further show that the linear drive 400 again has an axially moving piston 402, which is now, however, designed as a separate element and acts on the nacelle-side end 336 of the push rod 332. For this purpose, the piston 402 has a push rod-side end 420 and a nacelle-side end 422. The nacelle-side end 422 of the piston 402 is received in a piston-cylinder housing 404 and is designed to be pressurized with hydraulic fluid. For this purpose, a first working chamber 406 and a second working chamber 408 are provided, which, analogous to the exemplary embodiment described above, are pressurized with hydraulic fluid supplied by the pump unit 410 in order to move the piston 402 from the first position I to the second position II.

[0102] Furthermore, Figures 16, 19 and 20, 21 in particular show that the push rod-side end 420 of the piston 402 and the nacelle-side end 336 of the push rod 332 are accommodated in a push rod-piston connecting housing 426. The push rod-piston connecting housing 426 is in turn axially displaceably accommodated in a linear drive housing 428, which in turn is non-rotatably coupled to the rotor main shaft 6. The piston 402, more precisely the push rod-side end 420 of the piston 402, can be connected in a rotationally fixed manner to the push rod-piston connecting housing 426 (see Fig. 16, 19), but it is also possible, as shown in Figs. 20 and 21, that the nacelle-side end 336 of the push rod 332 is coupled in a rotationally fixed manner to the push rod-piston connecting housing 426.

[0103] In both cases, it must be taken into account that the linear drive housing 428 and the

[0104] Push rod 332 rotates together with the main rotor shaft 6, while the piston 402 of the linear drive 400 is stationary. For this reason, a first and a second bearing unit 430, 440 are arranged in the push rod-piston connecting housing 426. In the illustrated embodiment, the bearing units 430; 440 are designed as rolling bearings with an inner ring 432; 442, an outer ring 434; 444, and rolling elements 436; 446 arranged therebetween, but can also be a plain bearing. As can be seen in particular from the detailed views of Figures 19, 20 and 21, the bearing inner rings 432 and 442 are fastened in a rotationally fixed manner to the push rod 332 (see Figure 19) or in a rotationally fixed manner to the piston 402 (see Figures 20, 21), while the outer rings 434; 444 are received in a rotationally fixed manner by the push rod-piston connecting housing 426.

[0105] By providing the bearing units 430 and 440 in the push rod-piston connecting housing 426, a rotational decoupling between the rotating push rod 332 and the stationary piston 402 can be achieved. Accordingly, the push rod-piston connecting housing 426 of the embodiments illustrated in Figures 19 to 23 is also stationary, while in the embodiment of Figures 20, 21 it rotates together with the rotor main shaft 6, the linear drive housing 428, and the push rod 332.

[0106] As further illustrated in Figures 3, 5, and 16 to 23 and mentioned above, the linear drive 400 is also designed as a hydraulic piston drive in this exemplary embodiment. The piston 402 is guided in a cylinder 404 and, together with the cylinder, forms a first working chamber 406 and a second working chamber 408, which are alternately supplied with hydraulic fluid by means of a hydraulic fluid provided by the hydraulic pump 410 in order to move the piston 402 from a first position I to a second position II. For this purpose, the piston 402 has a flange 405 at the cylinder-housing-side end 422, with which the piston 402 is sealingly guided in the piston housing 404 and separates the working chambers 406, 408 from one another. The piston housing 404 is supported, on the one hand, in a rotationally fixed manner in the nacelle by means of a fastening means 414 and is at least partially enclosed by the linear drive housing 428.This ensures a defined position and fastening of the linear drive 400 in the gondola.

[0107] However, since, as mentioned above, the linear drive housing 428 is rotationally fixedly connected to the rotor main shaft 6 and therefore also rotates, while the piston housing 404 is stationary, rotational decoupling must also be provided between the piston housing 404 and the linear drive housing 428. In the exemplary embodiments illustrated in Figures 16 and 19 to 23, this rotational decoupling is achieved via two bearing units 450, 460, which, analogous to the bearing units 420, 430, are designed as rolling bearings, in particular tapered roller bearings, and each have an inner ring 452, 462, an outer ring 454; 464, and rolling elements 456; 466 arranged therebetween. The inner rings 452, 462 are arranged rotationally fixed on the piston housing 424, while the outer rings 454, 464 are arranged rotationally fixed in the linear housing 428. Of course, a plain bearing can also be used here or the bearing units can be arranged differently.

[0108] As can also be seen from the detailed views of Figures 19, 20 and 21, a preloading element 470 in the form of a spring is also arranged on the push rod-piston connecting housing 426, which preloads the push rod 332 into a first position I (see in particular Fig. 21). The first position I is preferably the feather position, so that in the event of a power failure or a lack of hydraulic fluid, the rotor blades 4 are rotated out of the flow, so that no torque is introduced into the underwater turbine 1. If the push rod-piston connecting housing 426 is connected to the piston 402 in a rotationally fixed manner, the spring is preferably supported, as can be seen from Figure 19, on the one hand on the push rod-piston connecting housing 426 and on the other hand on the piston housing 404. In contrast, if the push rod-piston connecting housing 426 is connected to the push rod 332 in a rotationally fixed manner (see Fig.20, 21), it rotates with the push rod 332 and the linear drive housing 428, so that the spring return element 470 can be supported on the one hand on the push rod-piston connecting housing 426 and on the other hand on the linear drive housing 428, as shown in Figures 21 and 22.

[0109] In addition to the preload element 470, which preloads the push rod 332 into a specific position, it is further advantageous if a locking device 480 is also provided, which blocks the linear movement of the push rod 332. The locking device 480 can have locking elements, for example in the form of bolts 482, 484, which, as shown in Figures 19 to 21, engage with the push rod-piston connecting housing 426 and fix it in a specific position. For this purpose, the push rod-piston connecting housing 426 has an opening 486 into which the bolt 482 or 484 can be inserted, holding the push rod 332 in a specific, predetermined position. The first position I (see Fig. 21) can again be the vane position of the rotor blades, while the second position II (see Fig. 20) can correspond to an optimal torque transmission position of the rotor blades 6. Of course, several locking pins can also be provided.

[0110] Alternatively or in addition to the bolts 482, 484, which interact with the push rod-piston connecting housing 426, it can also be provided, as can be seen from the exemplary embodiment in Figs. 22 and 23, that the locking device 480 acts directly on the push rod 332. For example, a bolt 488 can be arranged on the main rotor shaft 6, which extends through a bore 490 in the main rotor shaft 6 in the direction of the push rod 332 and there interacts with a bolt receptacle 492 provided in the push rod 332 in order to secure the push rod 332 in a specific position. In this case, too, it is advantageous that this position corresponds to the feathering position of the rotor blades 4, since in this case it is ensured that even in the event of a power failure or inactive control of the rotor blades, they remain rotated out of the flow and do not introduce any further torque into the underwater turbine.

[0111] The locking device 480 as well as other elements and sensors can in turn be energized or controlled via control units 416 arranged in the nacelle 8.

[0112] For this purpose, cables 418 can also be provided, which extend via corresponding rotary unions to the locking elements or the rotor blades in order to conduct signals or current.

[0113] List of reference symbols

[0114] 1 underwater turbine

[0115] 2 rotor hub

[0116] 4 rotor blades

[0117] 5 screws

[0118] 6 Rotor main shaft

[0119] 8 gondolas

[0120] 802 gondola interior

[0121] 10 Generator

[0122] 12 Generator rotor

[0123] 14, 16 bearing units rotor main shaft

[0124] 200 rotor hub arrangement

[0125] 202 rotor hub housing

[0126] 203 Rotor blade shaft lateral surface

[0127] 204 Rotor blade shaft

[0128] 205 tapered bearing surface for tapered plain bearing bush

[0129] 206 stop surface

[0130] 207 seaward end of the rotor blade shaft

[0131] 208 rotor hub end of the rotor blade shaft

[0132] 209 Rotor blade shaft bore

[0133] 210 Interior

[0134] 214 Rotor blade bearing arrangement

[0135] 220 offshore rotor blade shaft bearing unit

[0136] 230 rotor hub-side rotor blade shaft bearing unit

[0137] 221; 231 rolling bearings

[0138] 222; 232 inner ring

[0139] 223; 233 outer ring

[0140] 224; 234 Rolling elements; 235 Plain bearings; 236 Plain bearing bushes; 237 Inner bore of the bearing rings; 238 Sleeve section of the plain bearing bush; 239 Optional flange section of the plain bearing bush

[0141] S eewas serdi chtung

[0142] Gap between housing and rotor blade shaft

[0143] Dirt retention seal

[0144] shaft nut

[0145] Rib structures

[0146] Rotor hub housing section Rotor hub-side first housing section Sea-side second housing section Counter stop surface

[0147] Module tubular module housing section

[0148] Fasteners for module

[0149] Cable

[0150] Drive device housing

[0151] Spinner rotor-side sliding surface pairing sea-side sliding surface pairing ; 291 outer radial sliding surfaces ; 292 inner radial sliding surfaces ; 293 outer axial sliding surface ; 294 inner axial sliding surface

[0152] inner ring

[0153] Rotor blade twisting device

[0154] Bevel gear drive

[0155] Bevel gear on rotor blade shaft central bevel gear

[0156] Bevel gear drive (electric motor)

[0157] Gearbox

[0158] Transmission input shaft

[0159] Translation level

[0160] locking device

[0161] locking bevel gear

[0162] Thrust rod arrangement

[0163] push rod

[0164] Rotor hub side first end second end

[0165] Holding element

[0166] Connecting device

[0167] connecting rod

[0168] Connecting rod first connecting rod end second connecting rod end first connecting rod eye second connecting rod eye

[0169] bolt

[0170] bolt

[0171] Connecting rod-push rod connecting element; connecting rod holder

[0172] Connecting rod-rotor blade shaft connecting element; crank disc

[0173] Fasteners

[0174] Linear bearing unit

[0175] Bearing bush spherical plain bearing

[0176] outer ring

[0177] inner ring

[0178] bolt

[0179] O-ring linear actuator

[0180] hydraulic piston

[0181] flange

[0182] Hydraulic cylinder first working chamber second working chamber

[0183] pump

[0184] rotary union

[0185] Fastening in gondola

[0186] Control units

[0187] Cable

[0188] Slip ring, hub end of the piston, nacelle end of the piston, piston housing = cylinder, push rod-piston connecting housing, linear drive housing; 440 bearing units; 442 bearing inner ring; 444 bearing outer ring; 446 rolling elements; 460 bearing units

[0189] Reset element

[0190] Locking device; 484 locking elements = bolts

[0191] Bolt receiving opening

[0192] bolt

[0193] drilling

[0194] Bolt holder X distance

[0195] Y distance dli inner diameter d2i inner diameter

[0196] W bearing distance

[0197] L Length of the rotor blade shaft

Claims

Patent claims Rotor blade bearing for underwater turbine 1. Rotor blade bearing arrangement (214) for an underwater turbine (1), wherein the rotor blade bearing arrangement (214) is designed to rotatably support a rotor blade shaft (204) in a rotor hub housing (202), wherein the rotor blade shaft (204) has a seaward end (207) designed to be connected in a rotationally fixed manner to a rotor blade (4), and a rotor hub-side end (208) designed to be received by a rotor hub (2), and wherein the rotor blade bearing arrangement (214) has the rotor blade shaft (204) and a first seaward bearing unit (220) and a second rotor hub-side bearing unit (230), wherein the first and the second bearing unit (220; 230) are arranged at a distance W from one another, characterized in that the first and the second bearing unit (220; 230) are designed as plain bearings (225; 235), each an inner sliding surface (282; 292) and an outer sliding surface (281;291), wherein the inner sliding surface (292) of the first sliding bearing (225) is formed on the seaward end (207) of the rotor blade shaft (204) and the inner sliding surface (282) of the second sliding bearing (235) is formed on the rotor hub-side end (208) of the rotor blade shaft (204), and wherein the outer sliding surfaces (281; 291) of the first and second sliding bearings (225; 235) are formed by a rotor hub housing section (252; 262), wherein the rotor hub housing section (252; 262) is formed in a hollow tube shape and has a seaward end (255), on which the sliding layer (291) for the first sliding bearing (225) is formed, and a rotor hub-side end (254), on which the sliding layer (281) for the second sliding bearing (235) is designed, has.; 2. Rotor blade bearing assembly (214) according to claim 1, wherein the rotor hub housing section (252) is formed integrally with a rotor hub housing (202), or wherein the rotor hub housing section (262) is designed as a housing section (262) separate from the rotor hub housing (202) and can be installed into a rotor hub housing (202) together with the rotor blade bearing arrangement (214) and the rotor blade shaft (204).

3. Rotor blade bearing arrangement (214) according to claim 1 or 2, wherein the rotor blade shaft (204) has a diameter Dl at the location of the first offshore bearing unit (225) and wherein the bearing distance W is: 0.8*Dl < W < 2*Dl, preferably 1*D1 < W < 1.5*DL 4. Rotor blade bearing assembly (214) according to one of the preceding claims, wherein the first bearing unit (225) has a larger bearing diameter than the second bearing unit (235).

5. Rotor blade bearing assembly (214) according to one of the preceding claims, wherein at least one of the sliding surfaces (281; 291; 282; 292) has a sliding coating.

6. Rotor blade bearing arrangement (214) according to one of the preceding claims, wherein at least one plain bearing (225; 235) has radial sliding surfaces (281; 291; 282; 292) which are conical in shape, and / or wherein at least one plain bearing (225; 235) has radial sliding surfaces (281; 291; 282; 292) which are cylindrical in shape.

7. Rotor blade bearing arrangement (214) according to one of the preceding claims, wherein the rotor blade shaft (204) has at its seaward end (207) a stop step (206) with a first seaward annular axial sliding surface (293) which cooperates with a first complementary annular axial sliding surface (294) formed on the rotor hub housing section (252; 262).

8. Rotor blade bearing arrangement (214) according to one of the preceding claims, wherein the rotor blade shaft (204) has a stop step at its rotor hub-side end (208) which is designed to cooperate with a single-part or multi-part fastening ring, in particular a shaft nut (246) with a thrust washer, in order to fasten the rotor blade shaft (204) in the rotor hub housing section (252; 262) with a defined installation position, wherein the fastening ring (246) has a second rotor hub-side annular axial sliding surface (284) which cooperates with a second complementary annular axial sliding surface (283) formed on the rotor hub housing section (252; 262).

9. Rotor blade bearing arrangement (214) according to one of the preceding claims, wherein the inner sliding surfaces (281, 291) of the first and second sliding bearings (225; 235) are formed by a first and a second sliding bushing (226; 236) respectively, wherein the first sliding bushing (226) is attached to the seaward end of the rotor blade shaft (204), and the second sliding bushing (236) is attached to the rotor-side end of the rotor blade shaft (204).

10. Rotor blade bearing arrangement (214) according to one of claims 7 to 9, wherein a sliding disk is arranged between the first axial sliding surfaces (293; 294) and / or the second axial sliding surfaces (283; 284), wherein preferably at least one of the sliding disks is designed as a flange (229; 239) of the first and / or second sliding bushing (226; 236).

11. Rotor blade bearing arrangement (214) according to one of the preceding claims, wherein the first and / or second plain bearings (225; 235) are fluid-lubricated, wherein preferably the fluid is a corrosion-preventing fluid, in particular deionized and / or demineralized water.

12. Rotor hub assembly (200) for an underwater turbine (1) with a rotor hub housing (202) which is designed to be connected in a rotationally fixed manner to a rotor main shaft (6) for driving a generator (10), and is designed to receive and rotatably support at least one rotor blade shaft (204), wherein a rotor blade bearing assembly (214) according to one of the preceding claims is provided for supporting the rotor blade shaft (204).

13. The rotor hub assembly (200) of claim 12, wherein the rotor hub shell (202) is flooded with a fluid, the fluid being configured as a lubricant for the first and second plain bearings (225; 235).

14. Rotomabe assembly (200) according to claim 12 or 13, wherein the fluid has a density similar to water, or wherein the fluid is water, in particular seawater, but preferably deionized and demineralized water.

15. Rotor hub assembly (200) according to one of claims 12 to 14, wherein a sealing assembly (240) with pressure compensation function is arranged between the rotor blade shaft (204) and the rotor hub housing (202).

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