Rotor hub for underwater turbine

Abstract

The invention relates to a rotor hub (2) for an underwater turbine (1), comprising a rotor hub housing (202) which is designed to receive at least one rotor blade shaft (4). The rotor blade shaft (4) has a first rotor hub-side end (208), which is designed to be received in the interior (210) of the rotor hub housing (202), and a second sea-side end (207), which is designed to be rotationally fixed to a rotor blade (4). Additionally, the rotor blade shaft (4) is mounted in the rotor hub housing (202) by means of a first bearing unit (220) and a second bearing unit (230), wherein the first bearing unit (220) and the second bearing unit (230) are mutually spaced by a bearing distance (W), and the rotor hub (2) additionally has a rotor blade rotary drive device (316) comprising a rotatable driveshaft which is oriented perpendicularly to the rotor blade shafts (4) and at least one end of which is received in the interior (210) of the rotor hub housing (202), said end (208) which is received in the rotor hub housing (202) being rotationally fixed to a central drive bevel gear (314). The first end (208) of the rotor blade shaft (4) has a bevel gear (312) which interacts with the central drive bevel gear (314) such that the rotor blade shaft (4) rotates when the drive bevel gear (314) is operated.

Description

[0001] Description

[0002] Rotor hub for underwater turbine

[0003] Technical area

[0004] The present invention relates to a rotor hub assembly for an underwater turbine according to the preamble of claim 1.

[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] For this purpose, a drive unit is provided on the rotor blades or on the rotor blade shafts, which allows the rotor blades to be rotated.

[0008] However, such drive units are relatively bulky and therefore require a lot of installation space, which is not available, especially in smaller systems.

[0009] It is therefore an object of the present invention to provide a rotor hub arrangement that enables blade adjustment even in smaller underwater turbines. Summary of the invention

[0010] This object is achieved by a rotor hub arrangement according to patent claim 1.

[0011] The following describes a rotor hub for an underwater turbine with a rotor hub housing designed to accommodate at least one rotor blade shaft. The rotor blade shaft itself has a first rotor hub-side end designed to be accommodated in an interior space of the rotor hub housing, and a second seaward end designed to be non-rotatably fastened to a rotor blade, wherein the rotor blade shaft is furthermore mounted in the rotor hub housing by means of a first bearing unit and a second bearing unit. In order to enable blade adjustment even when there is little available installation space, it is further provided that the first bearing unit and the second bearing unit are arranged at a bearing distance W from one another in order to provide a bearing arrangement that allows the rotor blade shafts to extend far into the interior space of the rotor hub housing.In addition, the rotor hub further comprises a central rotor blade rotation drive device comprising a rotatable drive shaft oriented perpendicular to the rotor blade shafts, at least one of whose ends is accommodated in the interior of the rotor hub housing. Bevel gears are provided at the rotor blade shaft ends on the rotor hub side and at the end of the drive shaft accommodated in the rotor hub housing. These bevel gears mesh with each other to enable central adjustment of the rotor blade shafts. The drive shaft is connected in a rotationally fixed manner to a central drive bevel gear, while the bevel gear attached to the rotor blade shafts interacts with the central drive bevel gear such that, when the drive bevel gear is operated, all rotor blade shafts are rotated.

[0012] In order to achieve ideal tilting stiffness and thus high load-bearing capacity and at the same time to compensate for the effects of thermal differences in the rotor blade bearing arrangement, an embodiment is advantageous in which the first bearing unit and the second bearing unit are arranged at a distance from one another in the bearing distance W such that the following applies to the bearing distance W: 0.8*dli < W < 2*dli, preferably 1*dli < W < 1.5*dli, where dli is the inner ring bore diameter of the first inner ring.

[0013] The rotor hub itself preferably has a rotor hub housing that defines an interior space. 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 blade loads, the rotor hub housing can be further reinforced with stiffening ribs arranged in the interior space and increasing the structural stability of the rotor hub housing. Furthermore, as shown by a further advantageous embodiment, a mounting opening can be provided in the rotor hub housing, ensuring accessibility to the interior of the rotor hub.

[0014] Tapered roller bearings or plain bearings are preferably used as bearing units. In this case, a bearing arrangement is particularly preferred in which the first and second bearing units are designed as tapered roller bearings arranged in an O-arrangement. Alternatively, the bearing arrangement can also be provided using plain bearing units. Even when designed using plain bearing units, the two bearing units can be arranged in an O-arrangement. It is particularly preferred if the O-arrangement is designed such that a force flow is introduced from the bearings into the optionally provided stiffening ribs in the rotor hub housing. This ensures ideal and constant force and torque dissipation into the rotor hub housing, while at the same time requiring little material for the rotor hub housing.

[0015] Particularly in the case of tapered roller bearings, such an arrangement and spacing can compensate for the thermal growth of the rotor blade shaft as well as the growth of the bearing inner rings compared to the bearing outer rings, thus reducing the risk of preload loss in the bearing.

[0016] The first bearing unit is preferably located on the offshore side. Especially with the offshore bearing unit, the difference between the inner and outer bearing rings due to changing water temperatures and general thermal expansion is particularly large compared to the rotor-side bearing unit.

[0017] According to a further preferred embodiment, the rotor hub is further configured to be connectable to a rotor main shaft that drives a generator for power generation, or is formed integrally with the rotor main shaft, wherein the rotor main shaft has a longitudinal axis, and wherein a longitudinal axis of the drive shaft extends in the direction of the longitudinal axis of the rotor main shaft. This makes it possible to provide a particularly compact central drive system that can also be installed in small underwater turbines. Furthermore, a gearbox can be provided between the rotor main shaft and the generator, which converts a slow rotation of the rotor main shaft into a fast rotation of the generator.

[0018] Furthermore, it is preferred if the rotor blade rotation drive device is an electric or hydraulic geared motor. The geared motor can, for example, be an electric or hydraulic motor with a coupled gearbox. It is also possible to use a hydraulic direct drive, for example, a swivel cylinder, as the drive unit for the central bevel gear.

[0019] According to a further preferred embodiment, the rotor main shaft can be at least partially hollow, and the rotor blade twist drive device can be arranged in the hollow space of the rotor main shaft. This enables a particularly compact design that can also be used in underwater turbines with limited installation space.

[0020] Alternatively, a preferred embodiment is one in which the rotor blade twisting drive device is arranged opposite the main rotor shaft. Even then, the rotor blade twisting mechanism takes up little space and can also be used in small underwater turbines. It is particularly preferred if the rotor blade twisting drive device is arranged in a drive device housing that is connected to the rotor hub housing in a rotationally fixed and sealed manner. This ensures that the space available in the rotor hub housing interior is not further restricted by the drive mechanism.

[0021] It is also advantageous if a flow guidance structure extending in the direction of flow is provided on the rotor hub housing, which is designed to reduce water resistance. This can reduce the hydrodynamic drag of the rotor hub in the water, which in turn has a positive effect on the flow towards the rotor blades. Furthermore, the flow guidance structure can also actively improve the flow towards the at least one rotor blade.

[0022] Such a flow-guiding structure is particularly preferred when the drive unit is accommodated in an additional drive device housing. In this case, the flow-guiding structure is advantageously connected to the drive device housing. This prevents the additional drive device housing from impairing the flow characteristics of the underwater turbine.

[0023] According to another preferred embodiment, a gear is provided between the rotor blade shaft and the bevel gear connected to the rotor blade shaft. This allows the rapid rotation provided by an electric motor to be converted into a slow pivoting movement for rotor blade adjustment.

[0024] In a further advantageous embodiment, a locking device is provided in the rotor hub, which is designed to prevent rotation of the rotor blade shaft. In this case, the locking device can also be implemented, for example, via a self-locking gear arranged between the rotor blade shaft and the bevel gear connected to the rotor blade shaft. Alternatively or additionally, an embodiment is advantageous in which the locking device is connected in a rotationally fixed manner to the rotor hub and / or the main rotor shaft. In this case, for example, the locking device can have a stationary element that is rotationally fixedly connected to the rotor hub and / or the main rotor shaft. This allows the rotor blades to be fixed in a specific position, for example a feathering position. A feathering position is understood to be a position of the rotor blades in which no torque can be induced on the rotor blades by the flow.During maintenance work, or if, for example, a power supply for the rotor blade adjustment fails, it is advantageous for the entire underwater turbine to be shut down. Therefore, it is particularly preferred to use a locking device that is pre-tensioned to the feathering position.

[0025] According to a preferred embodiment, the locking device comprises an axially movable element, in particular with a toothed structure, which is designed to engage with the bevel gear and / or the drive bevel gear to prevent rotation of the rotor blade shaft. This allows direct action to be exerted on the rotor blade shafts.

[0026] It is particularly advantageous if the axially movable element can be moved by means of a hydraulic, mechanical, or electrical actuating device from a first position, in which no locking occurs, to a second position, in which locking occurs. Furthermore, it is advantageous if the axially movable element or the actuating device is designed such that the axially movable element of the locking device moves into the second position, in which locking occurs, without the action of the actuating device, wherein the second position of the axial element results in the rotor blades being locked in the feathered position.

[0027] It is further advantageous if, in the second position, the axially movable element is, on the one hand, rotationally fixedly connected to the stationary element and, on the other hand, engages with the bevel gear and / or the drive bevel gear. Preferably, the rotationally fixed connection between the stationary element and the axially movable element is provided by means of several circumferentially distributed bolts. This enables a simple but very direct locking of the adjustment mechanism.

[0028] Furthermore, it is preferred if the central drive bevel gear has a smaller diameter than the bevel gears connected to the rotor blade shafts. This allows the rapid rotation of the drive motor to be converted into a slow pivoting movement of the rotor blades without the need for an additional gear between the rotor blade shaft and the bevel gear. This allows a drive gear, which is optionally arranged between the drive motor and the central drive bevel gear, to be smaller in size to achieve the same rotational speed at the rotor blade.

[0029] 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.

[0030] Short character description

[0031] 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.

[0032] There show: Fig. 1 to Fig. 23: schematic sectional views of various different preferred embodiments for an underwater turbine.

[0033] Detailed description of the invention

[0034] In the following, identical or functionally equivalent elements are identified by the same reference symbols.

[0035] 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; however, 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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).

[0045] 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.

[0046] The bearing inner rings 222; 232, more precisely an inner bore 227, 237 of the bearing inner rings 222; 232, or the plain bearing bushings 226; 236, each have an inner diameter d11, d21 dimensioned such that the bearing inner rings 222, 232 or the plain bearing bushings 226; 236 can be connected in a rotationally fixed manner to the respective rotor blade shaft 204. Typically, the inner diameters d11, d21 are 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 bushings 226; 236 can be fastened to the rotor blade shaft 204 with a press fit.

[0047] 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). Of course, it is equally possible to non-rotatably connect the plain bearing bushes 226; 236 to the rotor hub housing section 252; 262, preferably by pressing them into the rotor hub housing section 252; 262.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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:

[0054] X:Y “ 6:1.

[0055] This allows a short distance between the rotor blade shafts 204-1, 204-2 with a relatively large rotor blade pitch.

[0056] Fig. 9 further shows that the rotor hub housing 202 has rib structures 250 which structurally reinforce the housing 202 and make it possible to provide a relatively thin-walled housing 202 which, however, can withstand high loads, in particular high water pressure at greater depths.

[0057] 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).

[0058] 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.

[0059] 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 when assembling the module 260 into the rotor hub housing 202 can be significantly simplified.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] Fig. 6 shows an embodiment in which, analogous to an O-arrangement of a tapered roller bearing, tapered plain bearing bushes are used, which are also arranged in an O-arrangement. The rotor blade shaft 204 can have a tapered plain bearing bush receiving surface (or sliding surface) 205; however, it is also possible for an additional bearing element, such as an inner ring 286, to be arranged on the rotor blade shaft 204. This bearing element supports the tapered plain bearing bush 236 or serves as a sliding surface for the tapered plain bearing bush. The angle of incidence of the tapered plain bearing arrangement is again selected such that force can be introduced into the reinforcing ribs 250.

[0069] The plain bearing bushings 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 bushings 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.

[0070] 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. 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-retaining function can be provided (see Figure 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 great stress and merely ensures the retention of dirt particles that could endanger the plain bearing pairing between the rotor housing 202 and the rotor blade shaft 204.

[0071] With such a fluid-lubricated bearing, sealing devices at 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.

[0072] 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 rotation 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 the rotor blade shaft being installed in the housing 202 itself (see Figures 2 and 10 to 13). The electric motor 316 can be designed compactly and in the interior 210 and rotor hub 2 (see Fig. 11) or in the rotor main shaft 6 designed as a hollow shaft (see Fig.12) may be arranged.

[0073] 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 gear is arranged between the bevel gear 312 and the rotor blade shaft 204 in the embodiment shown.

[0074] 317. The bevel gears 312-1, 312-2 are connected to a transmission input shaft

[0075] 318. The speed is reduced and the torque increased via a gear ratio 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.

[0076] 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).

[0077] Instead of an electric motor 316, the housing section 272 can of course also accommodate other types of drive units.

[0078] 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.

[0079] 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.

[0080] Instead of a bevel gear arrangement, a push rod arrangement 330 can also be used as the central rotor blade twisting device 300.

[0081] 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 cooperates with the rotor blade shaft 204 to twist 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 rotor main shaft 6. This bore can be sealed by means of a seal 374 (see Fig. 17) in the case of a flooded rotor hub.

[0082] The push rod 332 is moved axially by means of a linear drive 400, whereby 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).

[0083] 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.

[0084] 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 sliding bearings for bolts 354; 356, which ensure a rotatable fastening of the connecting rods 342. 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.

[0085] 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.

[0086] 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 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 so as to slide 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.

[0087] Furthermore, it can be seen in Fig. 8 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.

[0088] 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 middle position shown in Figure 11B, the connecting rod 342 is set at a maximum angle. Furthermore, it is preferred that the first maximum position I corresponds to a feathering position and the second maximum position II corresponds to a maximum force absorption position of the rotor blades 4 in the water flow. Furthermore, it is preferred that the push rod 332 is preloaded into the feathering 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.

[0089] 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.

[0090] 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.

[0091] 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 exemplary 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 exemplary embodiment of Figure 15, the hydraulic cylinder is inserted into the rotor main shaft 6.

[0092] Of course, in addition to the hydraulic linear drive 400 shown here, any other linear drive 400 can also be used, for example a pneumatic linear drive or a worm drive. 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 feedthrough 412.Such rotary unions 412 are known in the prior art and are therefore not described further.

[0093] The rotary union 412 is in turn non-rotatably attached 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] In both cases, it should be noted that the linear drive housing 428 and the push rod 332 rotate together with the rotor main 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.

[0098] 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.

[0099] 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.

[0100] However, since, as mentioned above, the linear drive housing 428 is non-rotatably connected to the rotor main shaft 6 and therefore also rotates, but the piston housing 404 is stationary, rotational decoupling must also be provided between the piston housing 404 and the linear drive housing 428.

[0101] In the 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 in a rotationally fixed manner on the piston housing 424, while the outer rings 454, 464 are arranged in a rotationally fixed manner in the linear housing 428. Of course, a plain bearing can also be used here, or the bearing units can be arranged differently.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] List of reference symbols

[0108] 1 underwater turbine

[0109] 2 rotor hub

[0110] 4 rotor blades

[0111] 5 screws

[0112] 6 Rotor main shaft

[0113] 8 gondolas

[0114] 802 gondola interior

[0115] 10 Generator

[0116] 12 Generator rotor

[0117] 14, 16 bearing units rotor main shaft

[0118] 200 rotor hub arrangement

[0119] 202 rotor hub housing

[0120] 203 Rotor blade shaft lateral surface

[0121] 204 Rotor blade shaft

[0122] 205 tapered bearing surface for tapered plain bearing bush

[0123] 206 stop surface

[0124] 207 seaward end of the rotor blade shaft

[0125] 208 rotor hub end of the rotor blade shaft

[0126] 209 Rotor blade shaft bore

[0127] 210 Interior

[0128] 214 Rotor blade bearing arrangement

[0129] 220 offshore rotor blade shaft bearing unit

[0130] 230 rotor hub-side rotor blade shaft bearing unit

[0131] 221; 231 rolling bearings

[0132] 222; 232 inner ring

[0133] 223; 233 outer ring

[0134] 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

[0135] S eewas serdi chtung

[0136] Gap between housing and rotor blade shaft

[0137] Dirt retention seal

[0138] shaft nut

[0139] Rib structures

[0140] Rotor hub housing section Rotor hub-side first housing section Sea-side second housing section Counter stop surface

[0141] Module tubular module housing section

[0142] Fasteners for module

[0143] Cable

[0144] Drive device housing

[0145] 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

[0146] inner ring

[0147] Rotor blade twisting device

[0148] Bevel gear drive

[0149] Bevel gear on rotor blade shaft central bevel gear

[0150] Bevel gear drive (electric motor)

[0151] Gearbox

[0152] Transmission input shaft

[0153] Translation level

[0154] locking device

[0155] locking bevel gear

[0156] Thrust rod arrangement

[0157] push rod

[0158] Rotor hub side first end second end

[0159] Holding element

[0160] Connecting device

[0161] connecting rod

[0162] Connecting rod first connecting rod end second connecting rod end first connecting rod eye second connecting rod eye

[0163] bolt

[0164] bolt

[0165] Connecting rod-push rod connecting element; connecting rod holder

[0166] Connecting rod-rotor blade shaft connecting element; crank disc

[0167] Fasteners

[0168] Linear bearing unit

[0169] Bearing bush spherical plain bearing

[0170] Outer ring

[0171] inner ring

[0172] bolt

[0173] O-ring linear actuator

[0174] hydraulic piston

[0175] flange

[0176] Hydraulic cylinder first working chamber second working chamber

[0177] pump

[0178] rotary union

[0179] Fastening in gondola

[0180] Control units

[0181] Cable

[0182] 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

[0183] Reset element

[0184] Locking device; 484 locking elements = bolts

[0185] Bolt receiving opening

[0186] bolt

[0187] drilling

[0188] Bolt holder X distance

[0189] Y distance dli inner diameter d2i inner diameter

[0190] W bearing distance

[0191] L Length of the rotor blade shaft

Claims

P a t e n t a n s p r ü c h e 1. Rotor hub (2) for an underwater turbine (1) with a rotor hub housing (202) which is designed to receive at least one rotor blade shaft (4), wherein the rotor blade shaft (4) has a first rotor hub-side end (208) which is designed to be received in an interior space (210) of the rotor hub housing (202), and a second sea-side end (207) which is designed to be rotatably fastened to a rotor blade (4), wherein the rotor blade shaft (4) is furthermore mounted in the rotor hub housing (202) by means of a first bearing unit (220) and a second bearing unit (230), characterized in that the first bearing unit (220) and the second bearing unit (230) are arranged at a bearing distance W from one another, and in that the rotor hub (2) furthermore has a rotor blade twist drive device (316) which has a (4) aligned, rotatable drive shaft,which is received with at least one of its ends in the interior (210) of the rotor hub housing (202) and is connected in a rotationally fixed manner to a central drive bevel gear (314) at the end (208) received in the rotor hub housing (202), and the rotor blade shaft (4) has at its first end (208) a bevel gear (312) which cooperates with the central drive bevel gear (314) in such a way that when the drive bevel gear (314) is operated, the rotor blade shaft (4) is rotated.

2. Rotor hub (2) according to claim 1, wherein the rotor hub (2) is further designed to be connectable to a rotor main shaft (6) which drives a generator (12) for power generation, or is formed integrally with the rotor main shaft (6), wherein the Rotor main shaft (6) has a longitudinal axis, and wherein a longitudinal axis of the drive shaft extends in the direction of the longitudinal axis of the rotor main shaft (6).

3. Rotoromabe (2) according to claim 1 or 2, wherein the rotor blade twist drive device (316) is an electric or hydraulic geared motor.

4. Rotor hub (2) according to one of the preceding claims, wherein the rotor main shaft (6) is at least partially hollow and the rotor blade twist drive device (316) is arranged in the hollow space of the rotor main shaft.

5. Rotor hub (2) according to claim 2 or 3, wherein the rotor blade twist drive device (316) is arranged opposite the rotor main shaft (6), wherein preferably the rotor blade twist drive device (316) is arranged in a drive device housing (272) which is connected in a rotationally fixed and sealing manner to the rotor hub housing (202).

6. Rotor hub (2) according to one of the preceding claims, wherein the rotor hub housing (202) further comprises a flow guide structure (274) extending in the direction of flow, which is designed to reduce water resistance, wherein preferably the flow guide structure (274) is connected to the drive device housing (272).

7. Rotor hub (2) according to one of the preceding claims, wherein a gear is arranged between the rotor blade shaft (6) and the bevel gear (312) connected to the rotor blade shaft (6). (317) is provided for.

8. Rotor hub (2) according to one of the preceding claims, wherein a locking device (320) is further provided in the rotor hub (2) which is designed to prevent rotation of the rotor blade shaft (4).

9. Rotomabe (2) according to claim 8, wherein the locking device (320) is biased into a locking position.

10. Rotor hub (2) according to claim 8 or 9, wherein the locking device (320) is connected in a rotationally fixed manner to the rotor hub (2) and / or the rotor main shaft (6), wherein preferably the locking device (320) comprises a stationary element which is connected in a rotationally fixed manner to the rotor hub (2) and / or the rotor main shaft (6).

11. Rotor blade shaft (2) according to one of claims 8 to 10, wherein the locking device (320) comprises an axially movable element (322), in particular with a toothed structure, which is designed to engage with the bevel gear (312) and / or the drive bevel gear (314) in order to prevent the rotation of the rotor blade shaft (204).

12. Rotomabe (2) according to claim 11, wherein the axially movable element (322) is movable by means of a hydraulic, mechanical or electrical actuating device from a first position in which no locking occurs to a second position in which locking occurs.

13. Rotomabe (2) according to claim 12, wherein in the second position the axially movable element (322) is on the one hand connected in a rotationally fixed manner to the stationary element and on the other hand is in engagement with the bevel gear (312) and / or the drive bevel gear (314), wherein the rotationally fixed connection between the stationary element and the axially movable element (322) is preferably provided by means of a plurality of circumferentially distributed bolts (324).

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