Underwater turbine

Abstract

The invention relates to an underwater turbine (1) having a rotor hub (2) which is connected to a rotor main shaft (6) for conjoint rotation and is designed to drive the rotor main shaft (6), wherein the rotor main shaft (6) extends in a nacelle (8) connected to the rotor hub (2) via the rotor main shaft (6) and there drives a generator (10) received therein, wherein the rotor hub (2) is furthermore designed to support at least one rotor blade (4), wherein the at least one rotor blade (4) is secured to a rotor blade shaft (204) and wherein the rotor blade shaft (204) is rotatably supported on the rotor hub (2) and has a first rotor-hub-side end (208), which projects into an interior of the rotor hub (2), and a second sea-side end (207) which can be secured to the respective rotor blade (4) for conjoint rotation, wherein in each case the rotor-hub-side end (208) of the rotor blade shafts (204) is designed to interact with a rotor blade adjustment arrangement (300) in order to rotate the at least one rotor blade shaft (204), wherein the rotor blade adjustment arrangement (300) furthermore has a translationally movable push rod (332) which has a first rotor-hub-side end (334) which is designed to project into the rotor hub (2) of the underwater turbine (1) and has at least one connection device (340) which is designed to be connectable to the rotor blade shaft (204) in such a manner that the translational movement of the push rod (332) is converted into a rotational movement of the at least one rotor blade shaft (204), and wherein the push rod (332) has a second nacelle-side end (336) which is designed to extend into the nacelle (8) of the underwater turbine (1), wherein at the nacelle-side end (336) of the push rod (332) a linear drive device (400) is provided which is designed to exert a translational force on the push rod (332) in order to translationally move the push rod (332), wherein the linear drive device (400) is directly or indirectly connected to the rotor main shaft (6) of the underwater turbine (1) such that between the rotor main shaft (6) and the linear drive device (400) an operational connection is provided which is designed such that the counter-force needed to apply the translational force can be introduced into the rotor main shaft (6).

Description

[0001] Description

[0002] Underwater turbine

[0003] Technical area

[0004] The present invention relates to an underwater turbine according to the preamble of claim 1.

[0005] Technical background

[0006] Underwater turbine rotor blades are typically attached to a rotor hub and can be mounted so they can rotate relative to the rotor hub. By rotating the rotor blades, the drive power can be varied. Furthermore, the rotor blade pitch control is used to rotate 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 which enables blade adjustment even in smaller underwater turbines.

[0010] Summary of the invention This object is achieved by an underwater turbine according to claim 1.

[0011] The following describes an underwater turbine comprising a rotor hub designed to drive a rotor main shaft. The rotor main shaft extends into a nacelle connected to the rotor hub via the rotor main shaft, where it drives a generator housed therein. The rotor main shaft can be non-rotatably attached to the rotor hub using fastening means, such as screws.

[0012] Furthermore, the rotor hub is designed to carry at least one rotor blade, wherein the rotor blade is fastened to a rotor blade shaft and wherein the rotor blade shaft is rotatably mounted on the rotor hub and has a first rotor hub-side end which projects into an interior of the rotor hub, and a second sea-side end which can be fastened in a rotationally fixed manner to the respective rotor blade, wherein the rotor hub-side end of the rotor blade shafts is in each case designed to cooperate with a rotor blade adjustment arrangement in order to rotate the at least one rotor blade shaft.

[0013] In order to provide a rotor blade adjustment arrangement even in smaller underwater turbines which have little installation space available, the rotor blade adjustment arrangement itself has a translationally movable push rod which has a first rotor hub-side end which is designed to protrude into the rotor hub of the underwater turbine and has at least one connecting device which is designed to be connectable to the rotor blade shaft in such a way that the translational movement of the push rod is converted into a rotational movement of the at least one rotor blade shaft, and wherein the push rod has a second nacelle-side end which is designed to extend into the nacelle of the underwater turbine.

[0014] In order to also be able to use smaller underwater turbines which have little installation space available but where high forces act on the rotor blades which must be applied by the rotor blade adjustment in order to rotate the rotor blades, it is further proposed that a linear drive device be provided at the nacelle-side end of the push rod which is designed to exert a translational force on the push rod in order to move the push rod translationally, wherein the linear drive is connected directly or indirectly to the main rotor shaft of the underwater turbine, so that an operative connection is provided between the main rotor shaft and the linear drive which is designed in such a way that the counterforce required to apply the translational force can be introduced into the main rotor shaft.

[0015] This allows the force required to adjust the rotor blades to be applied directly to the main rotor shaft instead of the nacelle. This also ensures that the bearing units that support the main rotor shaft in the nacelle do not have to be designed to absorb this force, which would be necessary if the linear drive were supported on the nacelle. This allows the bearing units of the main rotor shaft bearings to be smaller and can be optimized solely for the task of supporting the main rotor shafts.

[0016] According to a further preferred embodiment, the main rotor shaft is hollow, and the push rod is designed to extend through the main rotor shaft into the nacelle of the underwater turbine, and the linear drive is arranged in the nacelle. It is particularly advantageous if the push rod is mounted at its rotor hub end by means of a plain bearing bush, preferably with fluid lubrication. This allows for optimal use of the available installation space, allows even smaller underwater turbines to be equipped with a rotor blade adjustment system, or allows the underwater turbine to be designed more compactly overall.

[0017] To ensure support of the linear drive on the main rotor shaft, it is further preferred if the nacelle-side end of the push rod and the linear drive are at least partially enclosed by a linear drive housing that is non-rotatably attached to the main rotor shaft. This allows the force of the linear drive to be supported directly on the main rotor shaft.

[0018] The linear drive itself can, for example, be an electromechanical linear drive. Such drive devices are easy to install in the underwater turbine and can be operated using the electricity generated by the turbine or mains power. Furthermore, the linear drive device can be designed as an electric geared motor. This allows a rapid movement of an electric motor to be converted into a slow pivoting movement of the rotor blade adjustment. According to a further preferred embodiment, the linear drive has a translationally movable piston that acts translationally on the push rod in order to move the push rod translationally. Preferably, the linear drive is a hydraulic or pneumatic linear drive, and the piston is translationally movable by means of a hydraulic or pneumatic working fluid.This allows a large force to be exerted on the push rod, which can also cause the rotor blades to adjust against high water pressure acting on the rotor blades.

[0019] According to a further preferred embodiment, the nacelle-side end of the push rod and the first end of the piston are accommodated in a push rod-piston connecting housing, which is arranged in the linear drive housing for translational displacement. This creates a particularly simple coupling between the push rod and piston, which enables the direct transmission of the translational force of the piston to the push rod.

[0020] In order to enable adjustment of the piston in a hydraulic or pneumatic linear drive, it is further preferred that the piston is accommodated in a piston housing which surrounds the piston and is designed to define at least a first working chamber for the piston, wherein when the first working chamber is acted upon by a working fluid, the piston acts on the push rod in such a way that the push rod can be moved from a first to a second position.

[0021] The first position can be a so-called feathered position of the rotor blades, i.e., the position in which no torque is transmitted by the rotor blades. In other words, the rotor blades are turned out of the flow. Preloading the rotor blades to the first position advantageously ensures that in the event of a power failure or a problem with the hydraulic or pneumatic linear drive, e.g., a pump malfunction, the underwater turbine is shut down, allowing maintenance or repair work to be carried out.

[0022] Furthermore, a return element, in particular a spring, can be provided on the piston, which is designed to pre-tension the piston into the first position. Alternatively or additionally, the piston housing is further designed to define a second working chamber, wherein when the second working chamber is pressurised with a working fluid, the piston can be moved into the first position. This also allows the rotor blades to be actively rotated from the second position to the first position. Furthermore, this dual action of the piston enables any intermediate position between the first and second positions to be actively controlled. The spring can also be seen as a supporting element for the return to the first position.

[0023] Preferably, the piston is arranged in the piston housing in such a way that the piston essentially only performs a translational movement with respect to the piston housing.

[0024] According to a further preferred embodiment, the linear drive housing is non-rotatably connected to the main rotor shaft and at least partially surrounds the piston housing. The piston housing is non-rotatably supported in the nacelle, with a first rotationally decoupling bearing unit arranged between the linear drive housing and the piston housing. This enables relatively simple use of a hydraulic or pneumatic linear drive, since no rotary feedthrough for the hydraulic fluid or compressed air needs to be provided. Furthermore, with this configuration, the force exerted by the hydraulic or pneumatic drive can be supported on the main rotor shaft via the linear drive housing.

[0025] According to a further advantageous embodiment, the piston is connected to the push rod-piston connecting housing in a rotationally fixed manner, and the nacelle-side end of the push rod is rotatably mounted in the push rod-piston connecting housing by means of a second rotationally decoupling bearing unit. This means that the push rod-piston connecting housing itself is only translationally movable and essentially does not rotate, since the piston itself is only translationally movable.

[0026] Alternatively, the nacelle-side end of the push rod can be non-rotatably connected to the push rod-piston connecting housing, in which case the piston is rotatably mounted in the push rod-piston connecting housing by means of a second rotationally decoupling bearing unit. This means that the push rod-piston connecting housing itself rotates together with the push rod, while the piston remains stationary. Both designs allow for direct power transmission between the push rod and the piston, while simultaneously using a piston that can only be moved in a translational direction.

[0027] Alternatively or in addition to a return element arranged in the piston housing, which acts directly on the piston, an embodiment is also advantageous in which a return element is provided which is arranged such that it acts on the push rod-piston connecting housing. Here, too, the return element preloads the push rod into the first position, the so-called flag position. To ensure that the return element is not supported on one side by a rotating element and on the other side by a stationary element, in the case of a rotating push rod-piston connecting housing the return element can be supported directly on the linear drive housing, whereas in the case of a stationary push rod-piston connecting housing it can be supported on the piston housing.

[0028] Furthermore, a rotary union or slip ring can be arranged on the linear housing. The rotary union or slip ring can also be used to supply power to sensors or encoders located in the rotor main shaft, the rotor hub, the rotor blade shafts, or the rotor blades, and / or to transmit signals to or from the sensors. For this purpose, one or more cables can be routed from the nacelle to the rotor hub and others.

[0029] According to a further preferred embodiment, the connecting device with which the push rod is fastened to the rotor blades further comprises a first connecting rod and a second connecting rod, wherein each connecting rod has a connecting rod with a first end and a second end, and furthermore a first connecting rod eye is formed at the first end and a second connecting rod eye is formed at the second end, wherein the first connecting rod eye is connectable directly or indirectly to the push rod and the second connecting rod eye is connectable directly or indirectly to the rotor blade shaft. The connecting rod connection allows a simple rotary connection to be established with the rotor blades, which is also suitable for transmitting high torques. Furthermore, this makes it possible to provide a fully integrated, centralized rotor blade adjustment system, combining a compact design with cost efficiency.To connect the connecting rods to the push rod, the connecting device can, as shown in a further embodiment, further comprise a connecting rod-push rod connecting element having a first end and a second end, wherein the first end is rotatably connectable to the first connecting rod eye of the first connecting rod and the second end is rotatably connectable to the first connecting rod eye of the second connecting rod. The connecting rod-push rod connecting element further comprises a fastening device between the first and second ends, which is designed to attach the connecting rod-push rod connecting element to the push rod in a tension- and shear-resistant manner. This allows the force of the push rod to be distributed simultaneously and evenly between the two connecting rods.

[0030] It is particularly advantageous if the fastening device is arranged centrally on the connecting rod-push rod connecting element in order to achieve a uniform force distribution across both connecting rods. Furthermore, it is advantageous if a longitudinal axis of the connecting rod-push rod connecting element, which is defined between the first end and the second end of the connecting rod-push rod connecting element, is aligned perpendicular to a longitudinal axis of the push rod, which ensures that the force is applied to both connecting rods simultaneously.

[0031] According to a further advantageous embodiment, the connecting rod-push rod connecting element further has a first bolt at its first end and a second bolt at its second end, which are each received by the first connecting rod eye of the first connecting rod and the first connecting rod eye of the second connecting rod. This provides a sliding bearing between the connecting rod eye and the bolt, which ensures good rotatability with low susceptibility to failure. It is particularly preferred if a sliding bushing is arranged between the connecting rod eye and bolt, which reduces the friction between the components. Alternatively or additionally, a sliding coating can also be provided on the bolt, in the connecting rod eye and / or on the sliding bushing, which likewise ensures improved sliding properties.

[0032] Since both the connecting rod and the pin are typically made of steel, a sliding bearing for the pin in the connecting rod eye would result in a steel-on-steel sliding pair, which has relatively poor sliding properties. However, if 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 fiber composite material can, in particular, comprise PTFE as the sliding material.

[0033] Since the sliding coating is sometimes less robust than a sliding bushing and providing such a coating is significantly more complex, providing a sliding bushing is also very advantageous. The sliding bushing itself is usually made of a fiber composite material and has fibers, especially sliding fibers, embedded in a plastic matrix. Additionally, the fiber composite can also contain solid lubricant particles that support the sliding properties. Alternatively or additionally, the sliding bushing can also be made of a plastic that contains a solid lubricant.

[0034] Furthermore, an embodiment is advantageous in which the plain bearing between the connecting rod eye and the pin is fluid-lubricated. This also prevents friction on the sliding surfaces. Greases or oils can be used as the fluid, but it is also possible to provide water lubrication. This type of water lubrication is particularly advantageous for underwater turbines because, in order to prevent undesirable buoyancy of the underwater turbine, as many cavities as possible in the rotor hub, the rotor blade shaft and the rotor blades are flooded with a fluid that has a similar density to water and is preferably water. To prevent corrosion, however, deionized and demineralized water is preferably used as the fluid, which also serves as a lubricant for the plain bearing.Another advantage of a fluid-filled rotor hub is that there is no, or only a very small, pressure difference between the interior of the rotor hub and the surrounding seawater. This allows for the use of cost-effective seals that do not have to withstand large pressure differences during operation.

[0035] According to a further preferred embodiment, the connecting device further comprises a first connecting rod-rotor blade shaft connecting element having a first end and a second end, wherein the first end is rotatably connected to the second connecting rod eye of the first connecting rod and the second end is connected in a rotationally fixed manner to the first rotor blade shaft, as well as a second connecting rod-rotor blade shaft connecting element having a first end and a second end, wherein the first end is rotatably connected to the second connecting rod eye of the second connecting rod and the second end is connected in a rotationally fixed manner to the second rotor blade shaft. Preferably, the first and second connecting rod-rotor blade shaft connecting elements are designed such that an eccentric connection is achieved between the connecting rod and the rotor blade shaft. Preferably, the connecting rod-rotor blade shaft connecting element is designed as a crank disk.The crank disk can also be designed to serve as a cover for the rotor blade shaft. This also allows, for example, an embodiment in which the rotor blade shaft is designed as a hollow shaft, the interior of which is flooded with a fluid, such as seawater, while the rotor hub interior is designed to be dry. Such a seal also enables the rotor blades to be mounted on the rotor shafts even underwater. An O-ring seal, for example, can be provided as a seal between the crank disk and the rotor blade shaft.

[0036] According to a further preferred embodiment, the first connecting rod-rotor blade connecting element has, at its first end, an inner bearing element that is received by an outer bearing element formed by or attached to the second connecting rod eye of the first connecting rod, and the second connecting rod-rotor blade connecting element has, at its first end, an inner bearing element that is received by an outer bearing element formed by or attached to the second connecting rod eye of the second connecting rod. This also makes it possible to create a rotary connection between the second connecting rod eye and the respective connecting rod-rotor blade connecting element, which is particularly simple and, in particular, designed as a plain bearing.

[0037] In this exemplary embodiment, good torsion capability is also provided with low susceptibility to failure. It is particularly preferred if a sliding layer is arranged between the inner bearing element and the outer bearing element, which reduces friction between the components. The sliding layer can, for example, be provided as a sliding coating on the inner bearing element and / or the outer bearing element, thus ensuring improved sliding properties.

[0038] Since both the connecting rod and the connecting rod-to-rotor blade connecting element, and thus the inner bearing element and / or the outer bearing element, are typically made of steel, the sliding bearing of the inner bearing element and the outer bearing element would result in a steel-to-steel sliding pair, which has relatively poor sliding properties. However, if 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.

[0039] Since the sliding coating is sometimes less robust than a sliding bushing and providing such a coating is significantly more complex, providing a sliding bushing is also very advantageous. The sliding bushing itself is usually made of a fiber composite material and has fibers, especially sliding fibers, embedded in a plastic matrix. Additionally, the fiber composite can also contain solid lubricant particles that support the sliding properties. Alternatively or additionally, the sliding bushing can also be made of a plastic that contains a solid lubricant.

[0040] Furthermore, an embodiment is advantageous in which the plain bearing between the inner bearing element and the outer bearing element is fluid-lubricated. This also prevents friction on the sliding surfaces. Greases or oils can be used as the fluid, but it is also possible to provide water lubrication. This type of water lubrication is particularly advantageous for underwater turbines because, in order to prevent undesired buoyancy of the underwater turbine, as many cavities as possible in the rotor hub, the rotor blade shaft and the rotor blades are flooded with a fluid that has a similar density to water and is preferably water. To prevent corrosion, however, deionized and demineralized water is preferably used as the fluid, which also serves as a lubricant for the plain bearing.

[0041] In order to be able to compensate for misalignments between the connecting rod and the connecting rod-rotor blade connecting element, it is further preferred if the inner and outer bearing elements are designed as spherical bearing units, in particular as spherical plain bearings or as spherical roller bearings.

[0042] 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. Brief description of the figures

[0043] 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.

[0044] They show:

[0045] Fig. 1 to Fig. 23: schematic sectional views of various different preferred embodiments of an underwater turbine.

[0046] Detailed description of the invention

[0047] In the following, identical or functionally equivalent elements are identified by the same reference symbols.

[0048] 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 rotor main 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 rotor main shaft 6 can be fastened to the rotor hub 2, for example, by means of fastening means, in particular screws 5. The rotor blades 4 are subjected to a water flow, thereby causing the rotor hub 2 to rotate. The rotationally fixed connection of the rotor hub 2 to the rotor main shaft 6 in turn drives a rotor 12 of the generator 10, which is rotationally fixedly connected to the rotor main 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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 rotation 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.

[0055] 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.

[0056] The rotor blade bearing assembly 214 further comprises a first offshore bearing unit 220 and a second rotor hub 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.

[0057] 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).

[0058] 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.

[0059] 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 dli, d2i that is 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. 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 bushings 226; 236 can be fastened to the rotor blade shaft 204 with a press fit. The bearing outer rings 223, 233 are rotationally fixedly connected to a rotor hub housing section 252; 262. The rotor hub housing section 252 can be designed as an integral part of the rotor hub housing 202 (see, for example, Fig.2 and 3), however, it is also possible for the rotor hub housing section 262 to be a separate housing section which is connected to the rotor hub housing by means of fastening means 264 (see, for example, Fig. 4 and 5).

[0060] 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.

[0061] 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.

[0062] Furthermore, the rotor hub assembly 200 has a preferably dynamic seawater seal 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.

[0063] 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 1*dli W 1.5*dli.

[0064] 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 colder bearing outer rings 223, in rolling bearings 221; 231, particularly 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 if the bearing units 220, 230 are installed with a preload, as is usual with tapered roller bearings, for example.

[0065] 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.

[0066] 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 ≥ 1.

[0067] This allows a short distance between the rotor blade shafts 204-1, 204-2 with a relatively large rotor blade pitch.

[0068] Fig. 9 further shows that the Rotoman 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.

[0069] 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).

[0070] 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.

[0071] 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.

[0072] 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.

[0073] Alternatively, Figures 6 to 8 show the above-mentioned plain bearing of the rotor blade shaft 204, wherein Figures 6 to 8 depict a rotor shaft 204 that is inserted into the housing 202 of the rotor hub 2, wherein a sliding pair is formed between the tubular housing section 252 of the tubular hub housing 202, or the module housing section 262, and the rotor blade shaft 204, each forming a first offshore sliding surface pairing 280 and a rotor hub-side sliding surface pairing 290. Figures 6 to 8 depict only the integrated design with a housing section 252, not the modular design. However, the following statements apply analogously.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] With such a fluid-lubricated bearing, sealing devices at the rotor hub 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 Figure 8 in particular, can be designed entirely as a hollow shaft, which is closed, for example, only by means of crank disks. 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.

[0085] 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 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.

[0086] 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.

[0087] 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).

[0088] Instead of an electric motor 316, the housing section 272 can of course also accommodate other types of drive units.

[0089] 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.

[0090] 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 can be provided that is non-rotatably attached to the rotor hub housing 202. 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 in engagement 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.

[0091] Instead of a bevel gear arrangement, a push rod arrangement 330 can also be used as the central rotor blade twisting device 300.

[0092] 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.

[0093] 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).

[0094] As can be seen in particular from Figures 17 and 18, the push rod 332 is connected to the rotor hub-side end 208 of the rotor blade shaft 204 by means of a connecting device 340. The connecting device 340 has a connecting rod 342 for each 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 fastening of the connecting rod 342.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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 blade interior.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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 using a linear drive 400. In the exemplary embodiments shown 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 Fig. 14, the hydraulic cylinder 404 is received in the housing section 272, while in the exemplary embodiment of Fig. 15, the hydraulic cylinder is inserted into the main rotor shaft 6. 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.

[0104] 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.

[0105] 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.

[0106] 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, the push rod 332 is also 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] List of reference symbols

[0120] 1 underwater turbine

[0121] 2 rotor hub

[0122] 4 rotor blades

[0123] 5 screws

[0124] 6 Rotor main shaft

[0125] 8 gondolas

[0126] 802 gondola interior

[0127] 10 Generator

[0128] 12 Generator rotor

[0129] 14, 16 bearing units rotor main shaft

[0130] 200 rotor hub arrangement

[0131] 202 rotor hub housing

[0132] 203 Rotor blade shaft lateral surface

[0133] 204 Rotor blade shaft

[0134] 205 tapered bearing surface for tapered plain bearing bush

[0135] 206 stop surface

[0136] 207 seaward end of the rotor blade shaft

[0137] 208 rotor hub end of the rotor blade shaft

[0138] 209 Rotor blade shaft bore

[0139] 210 Interior

[0140] 214 Rotor blade bearing arrangement

[0141] 220 offshore rotor blade shaft bearing unit

[0142] 230 rotor hub-side rotor blade shaft bearing unit

[0143] 221; 231 rolling bearings

[0144] 222; 232 inner ring

[0145] 223; 233 outer ring

[0146] 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

[0147] S eewas serdi chtung

[0148] Gap between housing and rotor blade shaft

[0149] Dirt retention seal

[0150] shaft nut

[0151] Rib structures

[0152] Rotor hub housing section rotor hub-side first housing section sea-side second housing section

[0153] Counter stop surface

[0154] Module tubular module housing section

[0155] Fasteners for module

[0156] Cable

[0157] Drive device housing

[0158] Spinner rotor hub-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

[0159] inner ring

[0160] Rotor blade twisting device

[0161] Bevel gear drive

[0162] Bevel gear on rotor blade shaft central bevel gear

[0163] Bevel gear drive (electric motor)

[0164] Gearbox

[0165] Transmission input shaft

[0166] Translation level

[0167] locking device

[0168] locking bevel gear

[0169] Thrust rod arrangement

[0170] push rod

[0171] Rotor hub side first end second end

[0172] Holding element

[0173] Connecting device

[0174] connecting rod

[0175] Connecting rod first connecting rod end second connecting rod end first connecting rod eye second connecting rod eye

[0176] bolt

[0177] bolt

[0178] Connecting rod-push rod connecting element; connecting rod holder

[0179] Connecting rod-rotor blade shaft connecting element; crank disc

[0180] Fasteners

[0181] Linear bearing unit

[0182] Bearing bush spherical plain bearing

[0183] outer ring

[0184] inner ring

[0185] bolt

[0186] O-ring linear actuator

[0187] hydraulic piston

[0188] flange

[0189] Hydraulic cylinder first working chamber second working chamber

[0190] pump

[0191] rotary union

[0192] Fastening in gondola

[0193] Control units

[0194] Cable

[0195] Slip ring rotor hub end of the piston nacelle end of the piston piston housing = cylinder

[0196] Push rod-piston connecting housing

[0197] Linear actuator housing; 440 bearing units; 442 bearing inner ring; 444 bearing outer ring; 446 rolling elements; 460 bearing units

[0198] Reset element

[0199] locking device; 484 Sperrei emente=bolt

[0200] Bolt receiving opening

[0201] bolt

[0202] drilling

[0203] Bolt holder X distance

[0204] Y distance dli inner diameter d2i inner diameter

[0205] W bearing distance

[0206] L Length of the rotor blade shaft

Claims

P a t e n t a n s p r ü c h e 1. Underwater turbine (1) with a rotor hub (2) which is connected in a rotationally fixed manner to a rotor main shaft (6) and is designed to drive the rotor main shaft (6), wherein the rotor main shaft (6) extends into a nacelle (8) connected to the rotor hub (2) via the rotor main shaft (6) and drives a generator (10) accommodated therein, wherein the rotor hub (2) is further designed to carry at least one rotor blade (4), wherein the at least one rotor blade (4) is fastened to a rotor blade shaft (204), and wherein the rotor blade shaft (204) is rotatably mounted on the rotor hub (2) and has a first rotor-hub-side end (208) which projects into an interior of the rotor hub (2), and a second sea-side end (207) which can be fastened in a rotationally fixed manner to the respective rotor blade (4), wherein the rotor-hub-side end (208) of the rotor blade shafts (204) is designed to cooperate with a rotor blade adjustment arrangement (300),to rotate the at least one rotor blade shaft (204), wherein the rotor blade adjustment arrangement (300) further comprises a translationally movable push rod (332) having a first rotor hub-side end (334) which is designed to protrude into the rotor hub (2) of the underwater turbine (1) and having at least one connecting device (340) which is designed to be connectable to the rotor blade shaft (204) such that the translational movement of the push rod (332) is converted into a rotational movement of the at least one rotor blade shaft (204), and wherein the push rod (332) has a second nacelle-side end (336) which is designed to extend into the nacelle (8) of the underwater turbine (1), characterized in that a linear drive device (400) is provided at the nacelle-side end (336) of the push rod (332), which is designed to is to exert a translational force on the push rod (332),to move the push rod (332) translationally, wherein the linear drive device, (400) is connected directly or indirectly to the main rotor shaft (6) of the underwater turbine (1), so that an operative connection is provided between the main rotor shaft (6) and the linear drive device (400), which is designed such that the counterforce required to apply the translational force can be introduced into the main rotor shaft (6).

2. Underwater turbine (1) according to claim 1, wherein the rotor main shaft (6) is hollow and the push rod (332) is designed to extend through the rotor main shaft (6) into the nacelle (8) of the underwater turbine (1), and the linear drive device (400) is arranged in the nacelle (8).

3. Underwater turbine (1) according to claim 1 or 2, wherein the nacelle-side end (336) of the push rod (332) and the linear drive device (400) are at least partially surrounded by a linear drive housing (426), wherein the linear drive housing (426) is fixedly secured to the rotor main shaft (6) in a rotationally fixed manner.

4. Underwater turbine (1) according to one of the preceding claims, wherein the linear drive device (400) is an electromechanical linear drive.

5. Underwater turbine (1) according to one of claims 1 to 3, wherein the linear drive device (400) has a translationally movable piston (402) which acts translationally on the push rod (332) in order to move the push rod (332) translationally, wherein preferably the linear drive device (400) is a hydraulic or pneumatic linear drive and the piston (402) is translationally movable by means of a hydraulic or pneumatic working fluid.

6. Underwater turbine (1) according to claim 3 and 5, wherein the nacelle-side end (336) of the push rod (332) and a first rotor-side end of the piston (402) are received in a push rod-piston connecting housing (426) which is arranged so as to be translationally displaceable in the linear drive housing (426).

7. Underwater turbine (1) according to claim 5 or 6, wherein the piston (402) is received in a piston housing (424) surrounding the piston (402) and is designed to define at least a first working space (406) for the piston (402), wherein when the first working chamber is acted upon by a working fluid, the piston (402) acts on the push rod (332) in such a way that the push rod (332) can be moved from a first to a second position.

8. Underwater turbine (1) according to claim 7, wherein the piston housing (424) is further designed to define a second working chamber (408) for the piston (402), wherein when the second working chamber (408) is acted upon by a working fluid, the piston (402) acts on the push rod (332) such that the push rod (332) is movable from a second to a first position.

9. Underwater turbine (1) according to one of claims 5 to 8, wherein the linear drive housing (428) is connected in a rotationally fixed manner to the rotor main shaft (6) and at least partially surrounds the piston housing (424), and wherein the piston housing (424) is supported in a rotationally fixed manner in the nacelle (8), wherein a first rotationally decoupling bearing unit (450; 460) is arranged between the linear drive housing (428) and the piston housing (424).

10. Underwater turbine (1) according to one of claims 6 to 9, wherein the piston (402) is connected in a rotationally fixed manner to the push rod-piston connecting housing (426) and the nacelle-side end (336) of the push rod (332) is rotatably mounted in the push rod-piston connecting housing (426) by means of a second rotationally decoupling bearing unit (430; 440).

11. Underwater turbine (1) according to one of claims 6 to 9, wherein the nacelle-side end (336) of the push rod (332) is connected in a rotationally fixed manner to the push rod-piston connecting housing (426) and the piston (402) is rotatably mounted in the push rod-piston connecting housing (426) by means of a second rotationally decoupling bearing unit (430; 440).

12. Underwater turbine (1) according to one of claims 5 to 11, wherein a return element (470), in particular a spring, is further provided, which is designed to pretension the push rod (332) into the first position.

13. Underwater turbine (1) according to claim 12, wherein the return element (470) is arranged such that it acts on the push rod-piston connecting housing (426).

4. Underwater turbine (1) according to one of the preceding claims, wherein the push rod (332) at the rotor hub end (334) is connectable to the rotor blade shaft (204) via a connecting rod (344; 342) rotatably mounted on the push rod (332) and a connecting rod-rotor blade connecting element (358) rotatably mounted on the connecting rod (342) and rotatably attachable to the rotor blade shaft (204).

Images