Platform for a hub of a wind turbine

Abstract

The invention relates to a platform for a hub of a wind turbine. A platform assembly (20) for a hub (4) of a wind turbine (1) is configured to provide a working surface within the hub (4). The platform assembly (20) comprises a first platform (21) coupled to a hub access structure (14), wherein the hub access structure (14) extends in an axial direction (6) between a nacelle (3) of the wind turbine (1) and the hub (4) and provides access from the nacelle (3) to the hub (4).

Description

Technical Field

[0001] The present invention relates to a platform assembly for a hub of a wind turbine, the platform assembly being configured to provide a working surface within the hub. Background Art

[0002] Wind turbines are increasingly being used to generate electrical energy. A wind turbine typically includes a tower and a nacelle mounted on the tower, to which a hub is attached. A rotor is mounted at the hub and coupled to a generator. A plurality of blades extend from the rotor. The blades are oriented in such a way that the wind passing over the blades causes the rotor to rotate, thereby driving the generator to generate electricity. Thus, the rotational energy of the blades is transferred to the generator, which then converts the mechanical energy into electricity and transmits the electricity to a power grid.

[0003] Assembly of wind turbine components is a difficult task due to limited access to components from inside the wind turbine. In particular, mounting blades on the hub during installation of the wind turbine is difficult due to this limited accessibility. However, this limited accessibility also hinders maintenance tasks within the hub throughout the life cycle of the wind turbine.

[0004] Therefore, for installation and maintenance purposes, a platform inside the hub is required, which extends over the axial length of the hub to provide workers with access to the hub components. During operation of the wind turbine, the platform should not collide with any rotating parts. The platform provides a working surface for workers and technicians inside the hub to allow installation and maintenance tasks, such as the installation of blades during assembly of the wind turbine, or maintenance of blade bearings or main bearings, such as replacement or tightening of bolts of bearings, lubrication and replacement of lubricants of bearings, or other routine tasks completed during maintenance of the hub and components attached to the hub.

[0005] From the prior art, platforms at the hub for installation or maintenance purposes are known. In EP 2484893 A2, a maintenance platform is known which is mounted on a rotor and comprises a working surface for workers to step on in order to provide access to the blade root portion of the blade for maintenance purposes. The platform is arranged at an outer part of the hub and through an access hatch, workers can access the interior of the hub. However, the platform does not provide a working surface inside the hub, making maintenance and tightening bolts from inside the hub difficult.

[0006] One possibility to enable access through the working surface in the hub is to use a removable platform. This removable platform must be removed when the hub rotates so as not to collide with the components installed in the hub during the rotation of the hub. This greatly complicates the installation of the blades, since usually the blades are installed one after another by rotating the hub by about 120° to install the next blade. This process of blade installation together with the use of a removable platform has the disadvantage that the removable platform must be separated each time the hub rotates to avoid collisions between the platform and components of the hub. In this case, the removable platform is installed and separated three times for three rotations of the hub to install three blades. Thus, the platform is assembled in the hub for the first blade. Once the blade is installed, the platform is disassembled so that the hub can be rotated by about 120° without colliding with the platform. The platform is then assembled again and the second blade is installed. Thereafter, the platform is disassembled and the hub is rotated again by about 120°. This step is repeated for the third blade. When the installation is completed, the platform is disassembled and hoisted to the ground. Similarly, during maintenance work, the platform has to be lifted from the ground and coupled and uncoupled for each blade.

[0007] The use of removable platforms further increases the installation costs, since these platforms, which are usually made of multiple parts, need to be assembled and disassembled multiple times during blade installation. In addition, the parts of the removable platform need to be lifted, so for maintenance work, a crane may only be needed to lift the removable platform parts from the ground to the hub of the wind turbine.

[0008] An alternative to avoid the use of removable platforms is disclosed in document US2013 / 302175 A1. In this document, three circumferentially distributed support platforms are arranged between a hub cover as a cover covering the hub and the hub to provide access to the inside of the hub for maintenance. This arrangement of three platforms for three blades of a wind turbine enhances the accessibility of the blades from the inside of the hub, thereby simplifying the maintenance of the blades from the hub. However, this solution is not ideal because the platforms will rotate during the operation of the wind turbine, because they are coupled to the rotor, which causes the rotor to move more mass, thereby reducing the efficiency of the turbine. In addition, since the multiple platforms are installed in the hub, it will not be possible to install so many platforms for wind turbines with limited spacing in the hub. Finally, the installation cost increases, because each platform must be coupled to the hub, thereby increasing the material cost and assembly cost. Care must be taken so that during the rotation of the hub under normal wind turbine operation, the multiple platforms will not collide with other parts of the hub. Summary of the invention

[0009] An object of the present invention is to provide a platform assembly for a hub of a wind turbine, the platform assembly being configured to provide a working surface within the hub, which platform assembly overcomes the problems known from the prior art.

[0010] This is achieved by means of the platform assembly according to the invention.

[0011] According to the present invention, a platform assembly for a hub of a wind turbine configured to provide a working surface within the hub includes a first platform coupled to a hub access structure.

[0012] The hub access structure is a structure such as a platform extending in an axial direction between the nacelle and the hub of the wind turbine. The axial direction is the direction along the rotation axis of the wind turbine, i.e. along the rotation axis of the rotor, main shaft, etc. The hub access structure provides access for workers to move from the nacelle to the hub.

[0013] The first platform increases the working surface in the hub around the hub entry structure. This allows maintenance and installation work at the inner part of the hub in the surroundings of the hub entry structure, such as at the main bearing reinforcement plate or at the main bearing.

[0014] An advantage of having the platform assembly mounted directly within the hub at the hub access structure is that the platform assembly can be mounted at the hub during assembly of the wind turbine and does not need to be removed during operation of the wind turbine. This saves installation time compared to a removable platform that must be removed when the wind turbine is rotating.

[0015] The platform assembly may be used for installation as well as repair or maintenance of wind turbines.

[0016] A ladder or stairs may be arranged between the hub access structure and the platform assembly so that a worker can easily climb from the hub access structure to the platform assembly.

[0017] According to a preferred embodiment of the invention, the platform assembly is fixed. Fixed means that the platform assembly does not rotate around the rotation axis of the wind turbine during operation of the wind turbine. Therefore, to achieve this, the platform assembly and / or the hub entry structure are not coupled to a rotating part of the drive train of the wind turbine that rotates around the rotation axis of the wind turbine.

[0018] For example, the hub entry structure may be coupled to a housing of the nacelle, which housing is also a fixed component.Even if the nacelle is rotated by the yaw system, the nacelle housing does not rotate about the rotation axis of the wind turbine during operation of the wind turbine.

[0019] The hub access structure may extend between the nacelle and the hub of the wind turbine in an axial direction through an opening between the main bearing and the hub. The opening may be an opening at the main bearing or at a main bearing reinforcement plate to avoid contact between the rotating part of the main bearing and the hub access structure. Thus, neither the hub access structure nor the platform assembly rotates with the main bearing.

[0020] One advantage of having a fixed hub access structure and a fixed platform assembly is that the efficiency of the wind turbine is improved compared to a platform assembly coupled to the rotor of the wind turbine. This is due to the fact that the rotor does not require these additional parts to rotate, which do not contribute to converting the rotational energy of the hub into electrical energy through the generator.

[0021] Additionally, the platform assembly is designed in such a way that the rotating parts of the hub and the main bearing do not collide with the fixed hub entry structure and the fixed platform assembly during operation of the wind turbine.

[0022] According to another preferred embodiment of the present invention, the first platform extends in a direction substantially perpendicular to the axial direction. This means that the length of the first platform extending in a direction substantially perpendicular to the axial direction is greater than the length of the first platform extending in a direction substantially parallel to the axial direction.

[0023] This is particularly advantageous for avoiding collisions between the platform assembly and rotating parts of the hub. Thus, the first platform is elongated along the side of the plate in front of the main bearing reinforcement plate. Since the surface of the reinforcement plate is flat, rotation of the reinforcement plate does not result in a collision between the reinforcement plate and the first platform when the platform extends in a direction along the radial length of the reinforcement plate. In contrast, a platform elongated in the axial direction of the hub during operation of the wind turbine might collide with parts attached to the hub, such as pitch locks or other hydraulic actuators mounted in the hub.

[0024] The extension of the first platform in a direction substantially perpendicular to the axial direction provides a working surface close to the main bearing. This allows, for example, maintenance work to be performed on the main bearing, such as tightening bolts or changing lubricants.

[0025] According to another preferred embodiment of the present invention, the first platform has a position where the working surface of the first platform extends parallel to the ground. Therefore, workers can walk on the first platform to perform maintenance or installation work.

[0026] Preferably, the first platform has a position in which its running surface extends both parallel to the ground and in a direction substantially perpendicular to the axial direction. This allows maintenance or installation work on the main bearing to be performed by walking on the running surface of the first platform.

[0027] According to another preferred embodiment of the invention, the first platform has a position in which the working surface of the first platform extends substantially perpendicular to the ground. This position is a parked position of the first platform, where the platform assembly is positioned during operation of the wind turbine, and has the advantage of avoiding collisions between the first platform and the hub during rotation of the hub.

[0028] According to another preferred embodiment of the present invention, the platform assembly comprises a second platform, the second platform being configured to be coupled to the first platform. The second platform is configured to be positioned in such a way that a surface of the second platform extends substantially in the axial direction. This means that the length of the second platform extending in a direction substantially parallel to the axial direction is greater than the length of the second platform extending in a direction substantially perpendicular to the axial direction.

[0029] Preferably, the second platform is dimensioned in such a way that the working surface of the platform assembly is configured to extend from the hub access structure to the location of the blade bearing. Thus, a worker can reach the blade bearing from the platform assembly. This allows, for example, maintenance work to be performed on the blade bearing, such as tightening bolts or changing lubricants.

[0030] According to another preferred embodiment of the present invention, the second platform has a position where the working surface of the second platform extends parallel to the ground. Therefore, workers can walk on the first platform to perform maintenance or installation work.

[0031] Preferably, the second platform has a position in which its running surface extends both parallel to the ground and in a direction substantially parallel to the axial direction. This allows maintenance or installation work on the blade bearing to be performed by walking on the running surface of the second platform.

[0032] According to another preferred embodiment of the present invention, the second platform is a removable platform.Therefore, the second platform is releasably coupled to the first platform.

[0033] A releasable coupling is understood to be a connection between components that can be released without damaging the individual components. The connection can be achieved by a semi-permanent joining method. For example, bolts, screws, pins, rivets, threads, studs or other longitudinal members can be used as fasteners for the components.

[0034] Thus, the second platform can be mounted on the first platform when it is needed and subsequently, detached from the first platform during operation of the wind turbine.The second platform can then be stored in the nacelle or hoisted to the ground during operation of the wind turbine.

[0035] According to another preferred embodiment of the present invention, the second platform is movable or slidable between a first position below, on top of or in front of the first platform and a second position in which the second platform extends substantially in the axial direction.

[0036] Thus, the second platform is stackable in this first position. This has the advantage that when the second platform is stowed or stacked above, below or in front of the first platform, the working surface extending in the axial direction is reduced, thereby significantly reducing the working surface of the platform assembly when the platform assembly is not needed. This may be the case during operation of the wind turbine. By reducing the size of the working platform, collisions between the platform assembly and the rotating part of the hub may be avoided.

[0037] In addition, the slidable or movable system allows for a quick extension of the second platform in the axial direction. Thus, when a working surface is needed, a worker can, for example, rotate the second platform from a parked, stowed position to an extended position and lock the second platform in the extended position, i.e. a position in which the second platform is substantially extended in the axial direction. This significantly reduces installation time, since the second platform can be installed much faster than with a removable platform. In addition, the second platform is not hoisted from the ground to the hub, since the second platform is stowed at the first platform during operation of the wind turbine, which also reduces installation costs by reducing installation time and avoiding the use of a crane for hoisting.

[0038] According to another preferred embodiment of the present invention, the platform assembly comprises a telescopic system for moving the second platform from a stowed position to an extended position, in which the surface of the second platform is substantially extended in the axial direction. The telescopic system comprises a slidable telescopic surface member, which can slide from the stowed position to the extended position, thereby increasing the surface of the second platform.

[0039] According to another preferred embodiment of the present invention, the second platform telescopic system includes a telescopic arm and a telescopic surface member.

[0040] Preferably, the telescoping system comprises at least one telescoping surface member mounted to be telescopically slidable from its stowed position superimposed above, below or in front of the first platform to its extended position extending in the axial direction.

[0041] Preferably, the telescopic system comprises a first telescopic surface member and a second telescopic surface member, both mounted so as to be telescopically slidable relative to each other in an axial direction.

[0042] Preferably, the first telescopic surface member is arranged to surround the second telescopic surface member in the stowed position.

[0043] Preferably, the first telescopic surface member is arranged to overlap above or below the second telescopic surface member in the stowed position.

[0044] An advantage of having two telescoping surface members slidable relative to each other is that by sliding the telescoping surfaces, and thereby extending the working surface of the platform assembly in the axial direction, the working surface of the second platform is significantly increased.

[0045] Preferably, the telescopic system comprises a plurality of telescopic surface members which are mounted so as to be telescopically slidable relative to each other in the axial direction. This has the advantage that the axial extension of the working surface is increased by each telescopic surface member of the telescopic system and at the same time this allows a considerable reduction of the working surface in the stowed position, since the telescopic surface members can be superimposed on each other, thereby considerably reducing the surface of the second platform in the stowed position.

[0046] The telescopic system includes a telescopic arm coupled to a telescopic surface member. The telescopic arm may include a plurality of hollow cylinders stacked on top of each other, which can slide relative to each other and increase the length of the telescopic arm.

[0047] Using an actuator system, the telescopic arm can be extended from a stowed position to an extended position, thereby also sliding the telescopic surface member to which the telescopic arm is attached and thereby increasing the surface of the telescopic system.

[0048] According to another preferred embodiment of the invention, the platform assembly comprises a rotation system for rotating the second platform relative to the first platform. For example, the second platform may have an edge pivotally connected to the first platform. This allows the second platform to be rotated from a stowed position, in which the second platform is superimposed above or below the first platform or also superimposed within the first platform, to an extended position, thereby increasing the working surface of the platform assembly in the axial direction. The rotation system has the advantage that it reduces the time for the platform assembly to extend from the stowed position to the extended position, compared to a system in which the second platform must be connected to the first platform.

[0049] According to another preferred embodiment of the present invention, the rotation system comprises a hinge or pin joint for rotational movement. The hinge or pin joint can be coupled to the first platform and the second platform by means of a bushing. For example, the hinge or pin joint can be coupled to the edge of the first platform and the edge of the second platform to pivotally couple the second platform to the first platform.

[0050] According to another preferred embodiment of the present invention, the rotation system comprises a locking pin and a lock socket for fixing the second platform in the stowed position and / or the rotated position. The locking pin is a pin with a smaller diameter than the lock socket, and the locking pin can be introduced into the lock socket to fix the locking pin to the lock socket, thereby fixing the components attached to the locking system together.

[0051] Preferably, the locking pin is coupled to the second platform and the locking socket is coupled to the first platform to lock the second platform to the first platform.

[0052] Preferably, the locking pin is coupled to the first platform and the locking socket is coupled to the second platform to lock the second platform to the first platform.

[0053] Preferably, one locking pin is coupled to the second platform and two locking sockets are coupled to the first platform. In the stowed position, the locking pin of the second platform is fixed at the first locking socket of the first platform, thereby fixing the second platform to the first platform in this position. When the locking pin is released from the first locking socket to rotate the second platform relative to the first platform, the locking pin is then rotated, for example 90°, about the axis of the hinge or pin joint to a rotational position, which is a position in which the second platform extends in the axial direction. In this position, the second locking socket of the first platform can be positioned so that the locking pin of the second platform can engage with the second locking socket of the first platform to fix the second platform to the first platform in this rotational position.

[0054] Preferably, one lock socket is coupled to the second platform and two lock pins are coupled to the first platform. In the stowed position, the lock socket of the second platform is fixed at the first lock pin of the first platform, thereby fixing the second platform to the first platform in this position. When the first lock pin is released from the lock socket to rotate the second platform relative to the first platform, the lock socket of the second platform is then rotated, for example 90°, about the axis of the hinge or pin joint to a rotational position, which is a position in which the second platform extends in the axial direction. In this position, the second lock pin of the first platform can be positioned so that the lock socket of the second platform can engage with the second lock pin of the first platform to fix the second platform to the first platform in this rotational position.

[0055] According to another preferred embodiment of the invention, the swivel system comprises a spring. The spring pulls the second platform towards the first platform so that it helps to lock the second platform to the first platform, because pulling the second platform towards the first platform by means of the spring reduces the force required by a worker to pull the second platform towards the first platform in order to lock the two platforms together, for example by means of a locking pin-lock-socket system.

[0056] In order to rotate the second platform relative to the first platform, the second platform is pushed to overcome the force of the spring, thereby releasing the locking pin from the lock socket and disengaging the locking system. Then, the second platform is rotated to the rotation position. Finally, the second platform is released, and the force of the spring brings the second platform toward the first platform, and the locking pin and the lock socket are combined together by the force of the spring, thereby locking the second platform to the first platform.

[0057] The spring may bear against or be supported by a bushing or nut attached to the first or second platform.Using a spring has the advantage that it makes the second platform flush with the first platform and helps to secure the two platforms together, thereby increasing the safety of the platform assembly.

[0058] According to another preferred embodiment of the present invention, the platform assembly has a first state in which the second platform is separated from the first platform or stowed above, below or in front of the first platform to limit the surface of the platform assembly within the hub, especially when the hub rotates. The first state is the parking state of the platform assembly.

[0059] Having a detached or stowed second platform reduces the surface of the platform assembly within the hub, thereby allowing the platform assembly to be parked in the hub without having to remove the platform assembly during operation of the wind turbine. Thus, at least the first platform of the platform assembly can be left parked in the hub in the first state while the hub is rotating.

[0060] In the first state, the surface of the platform assembly extending in the axial direction is minimized.

[0061] According to another preferred embodiment of the present invention, the first platform is movable between a horizontal position and a vertical position, in particular when the platform assembly is in the first state.

[0062] In this horizontal position, the working surface of the first platform extends in a direction parallel to the ground. Therefore, the normal vector of the working surface is parallel to the gravity vector. In this position, the worker can walk on the working surface of the first platform.

[0063] In this vertical position, the working surface of the first platform extends in a direction perpendicular to the ground. Therefore, the normal vector of the working surface is perpendicular to the gravity vector.

[0064] In the first state, the platform assembly can be parked in a horizontal position or a vertical position, depending on the rotating components of the hub, and is used to avoid collisions between the platform assembly and these rotating components. The selected position of the first state depends on the hub design and the rotating components of the hub, but both positions or intermediate positions between the two positions can be used as the parking position or the first state of the platform assembly.

[0065] If the second platform is stacked or folded together with the first platform, the second platform can also be moved between the horizontal position and the vertical position. Therefore, the platform assembly can be moved between the horizontal position and the vertical position.

[0066] According to another preferred embodiment of the present invention, the platform assembly has a second state, in which the second platform is coupled to the first platform, wherein the second platform extends in the axial direction to increase the working surface within the hub.

[0067] Thus, in the first state, the working surface of the platform assembly extends substantially in a direction perpendicular to the axial direction, since this is the direction in which the first platform extends. In the second state, the working surface extends in a direction perpendicular to the axial direction due to the first platform and in a direction parallel to the axial direction due to the second platform in the extended state.

[0068] According to another preferred embodiment of the present invention, the second platform comprises a platform support member, which is configured to support the platform in the second state. The platform support member supports the second platform in the second state on the wheel hub. Therefore, the platform support member is arranged between the wheel hub and the second platform. Since the wheel hub does not rotate in the second state of the platform assembly, the platform assembly can be directly supported on the wheel hub. Therefore, the platform assembly is supported both on the wheel hub and on the wheel hub access structure, which increases the stability of the platform assembly.

[0069] The platform support may also be arranged between the platform assembly and the blade bearing reinforcement plate, or between the platform assembly and the pitch lock.

[0070] According to another preferred embodiment of the invention, the platform assembly has a third state in which the platform assembly moves between a horizontal position and a vertical position at an inclined angle in order to rotate the hub without causing the hub to collide with the platform assembly. In this position, a collision between the rotating hub and the platform assembly with the second platform in the extended state can be avoided. This is particularly useful because the platform assembly can then reach the three blade bearings by rotating the hub without having to switch to the first state at each rotation.

[0071] In the third state, the platform is not supported on the rotating hub, so if a platform support disposed between the rotating hub and the platform assembly is used, it should be removed before rotating the hub.

[0072] The platform assembly in the third state is advantageous in order to be able to rotate the hub by 120° in the axial direction from one blade bearing to the next blade bearing without the platform assembly colliding with other rotating parts of the hub. Therefore, when the blade bearing installation work or maintenance work of the first blade bearing is completed, the platform support is subsequently removed and the platform assembly is moved from the second state to the third state. Thereafter, the hub is rotated by 120° so that the second blade bearing is located next to the platform assembly. The platform assembly is then moved from the third state to the second state and the platform support is attached to the platform assembly. At this point, the blade bearing installation work or maintenance work can be started for the second blade bearing. The same process is carried out for the third blade bearing.

[0073] This is advantageous because it significantly reduces installation time compared to switching from the second state to the first state when the hub is to be rotated to reach the next blade bearing. Thus, when the platform assembly is in the third state, the second platform does not need to be separated or stacked with the first platform in the first state in order to rotate the hub. The third state is a temporary position that allows rapid installation or maintenance of the blade bearing and allows the hub to rotate freely without colliding with any components of the platform part.

[0074] According to another preferred embodiment of the present invention, the platform assembly further comprises a guardrail. The guardrail improves the safety of the platform by preventing workers or equipment from falling from the edge of the platform.

[0075] The guardrails may be detachable guardrails which are detached when the platform assembly is in the first state and are attached when the platform assembly is in the second state and / or the third state. It is advantageous to detach the guardrails when the platform is in the first state to reduce the volume occupied by the platform assembly during operation of the wind turbine, thereby reducing the risk of collision between the rotating part of the hub and the platform assembly.

[0076] A detachable railing may be attached to the first platform and / or the second platform.

[0077] According to another preferred embodiment of the present invention, the platform assembly further comprises a damper configured to absorb shock pulses. The use of a damper is useful for moving the platform assembly from a vertical position to a horizontal position or from a third state to a horizontal position because it absorbs shock and slows the rotation between these positions. It also allows the worker to rotate the platform assembly with less effort. The damper also dampens and stabilizes the platform assembly when the worker walks on the walking surface and provides further support for the stability of the platform.

[0078] The damper may be a shock absorber, such as a gas or hydraulic spring or a mechanical spring.

[0079] The damper also stabilizes the platform assembly in the third state and maintains the platform assembly at the tilt angle during the third state.

[0080] The damper may be a retractable damper mounted or releasably connected between a rotating component of the hub, such as the hub itself or the main bearing reinforcement plate, and the first or second platform of the platform assembly.

[0081] The damper may also be a fixed component mounted between two fixed parts, for example between the wheel hub entry structure and the first platform of the platform assembly. This has the advantage that the damper does not need to be separated from the platform assembly when the wheel hub rotates.

[0082] According to another preferred embodiment of the present invention, the platform assembly is supported on the main bearing or the main bearing reinforcement plate in a horizontal position by means of a support bracket.

[0083] According to another preferred embodiment of the present invention, the support bracket includes a support bracket pin and a support bracket socket. The support bracket pin can be coupled to the platform assembly, and the support bracket socket can be coupled to the main bearing reinforcement plate. When the first platform is in a horizontal position, using the support bracket to support the platform assembly increases the stability of the platform assembly and helps to fix the platform assembly to the main bearing.

[0084] In order to lock the supporting bracket pin to the supporting bracket socket, the platform assembly can be moved from a vertical position to a horizontal position, thereby automatically introducing the supporting bracket pin into the supporting bracket socket.

[0085] After the platform assembly is supported by the support bracket, the second platform of the platform assembly can be extended to the second state in the axial direction. When the platform assembly or at least the first platform of the platform assembly is in a horizontal position, the platform assembly is fixed by the support bracket for workers to work on the working surface of the platform assembly.

[0086] The main bearing reinforcement plate is usually in an inclined position, i.e., at a specific angle to the vertical position. This feature can be used to avoid collision between the support bracket pin and the support bracket socket when the main bearing and the hub rotate with the platform assembly parked in the vertical position during operation of the wind turbine. Due to the inclination of the main bearing reinforcement plate, there is a gap between the support bracket pin coupled to the platform assembly and the support bracket socket coupled to the main bearing reinforcement plate, which allows the main bearing to rotate without colliding with the platform assembly or the support bracket pin.

[0087] Therefore, it is advantageous to have the platform assembly in a vertical position in its parked or first state, particularly when the main bearing reinforcement plate is tilted. In the parked state of the platform assembly, the wind turbine can rotate freely in an operational mode without colliding with the platform assembly.

[0088] The support bracket may be a built-in support bracket, wherein a portion of the support bracket is attached to the main bearing or the main bearing reinforcement plate, and another portion of the support bracket is attached to the platform assembly. This has the advantage that a worker does not have to move any portion in order to secure the platform assembly to the main bearing, and the portions can be coupled together by rotating the platform assembly from a vertical position to a horizontal position.

[0089] Yet another aspect of the present invention is a method for increasing a working surface in a wheel hub by means of a platform assembly, the platform assembly comprising a first platform coupled to a wheel hub access structure and a second platform coupled to the first platform, wherein the platform assembly has: a first state in which the second platform is stowed above, below or in front of the first platform; and a second state in which the second platform is extended in an axial direction to increase the working surface in the wheel hub, wherein the platform assembly comprises a rotation system. The method comprises the step of rotating the second platform relative to the first platform from the first state to the second state.

[0090] This method allows increasing the axial surface of the platform assembly in order to be able to reach the blade bearings through the platform assembly.

[0091] According to another aspect of the present invention, the platform assembly has a third state in which the platform assembly moves between a horizontal position and a vertical position at an inclined angle, and the method further comprises the step of rotating the platform assembly from the second state to the third state.

[0092] This allows the hub to be rotated during maintenance or installation work to be able to reach the next blade bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] In order to facilitate the understanding of the characteristics of the invention and as an integral part of this specification, some drawings are attached, on which there are illustrative and non-limiting reference numerals, and the following drawings are presented:

[0094] Figure 1 A perspective view of a wind turbine is shown.

[0095] Figure 2 The hub access structure is shown through the main bearing reinforcement plate opening, which allows workers to enter between the main bearing and the hub.

[0096] Figure 3 and Figure 4 Shows Figure 2 A wheel hub entry structure, wherein a first platform of a platform assembly is coupled at the wheel hub entry structure, and the platform assembly is rotatably fixed to the wheel hub entry structure.

[0097] Figure 5 Shows Figure 2 The hub enters the structure, wherein the platform assembly includes a first platform and a second platform coupled to the first platform.

[0098] Figure 6 Another perspective view shows Figure 5 A platform assembly, wherein a railing is installed at the platform assembly and the platform assembly is supported by a platform support.

[0099] Figure 7 The coupling of the second platform of the platform assembly is shown, which is achieved by means of a pin coupling.

[0100] Figure 8 and Fig. 9 A second platform is shown, which is stacked below the first platform and has a telescoping system for extending the second platform in the axial direction.

[0101] Figures 10 to 17 A second platform stacked below a first platform is shown, wherein the platform assembly includes a rotation system, a locking system, and a telescoping system.

[0102] Figures 18 to 21 A telescoping system of a platform assembly for extending the working surface of a second platform is shown.

[0103] Fig. 22 A platform assembly is shown mounted at a hub entry structure in a parked position or first state, the platform assembly including a damper mounted between the platform assembly and the hub entry structure.

[0104] Fig.23 The platform assembly is shown in a horizontal position with the damper mounted between the platform assembly and the hub entry structure.

[0105] Fig.24 The platform assembly is shown in a third condition at an inclined angle.

[0106] Fig.25 Attachment of the platform assembly by means of support brackets is shown.

[0107] Figures 26 to 28 The platform assembly including the support bracket and the rotation of the tilted main bearing reinforcement plate are shown. DETAILED DESCRIPTION

[0108] Figure 1 A wind turbine 1 is shown comprising a tower 2, a nacelle 3 arranged at an upper end of the tower 2, a hub 4 connected to the nacelle 3 and three blades 5 extending from the hub 4. The wind turbine 1 has an axial direction 6, which is a direction along a rotation axis of the wind turbine 1.

[0109] Figure 2 A hub access structure 14 is shown through the main bearing reinforcement plate opening 15 which allows a worker to gain access between the main bearing and the hub 4 .

[0110] The main bearing reinforcement plate opening 15 rotates with the rotation of the hub 4, and the hub access structure 14 is a fixed component and, therefore, does not rotate about the axial direction 6 of the wind turbine 1 during operation of the wind turbine 1. Therefore, the hub access structure 14 passes through the main bearing reinforcement plate opening 15 so that there is no contact between the hub access structure 14 and the main bearing reinforcement plate 10. This arrangement allows the hub access structure 14 to be retained during operation of the wind turbine 1, since it does not have to be separated from the nacelle 3, as it does not hinder the rotation of the hub 4.

[0111] Figure 3 and Figure 4 Shows Figure 2 The wheel hub enters the structure 14 , wherein the first platform 21 of the platform assembly 20 is coupled at the wheel hub enters the structure 14 , and the platform assembly 20 is rotatably fixed to the wheel hub enters the structure 14 .

[0112] The first platform 21 provides a walking surface for workers to perform maintenance or installation work at the main bearing or the main bearing reinforcement plate 10, such as tightening the fastener 12 of the fastener ring 13 or replacing lubricant.

[0113] Since the first platform 21 is fixed, the main bearing can be rotated so as to reach all the fastening devices 12 of the fastening device circle 13 of the main bearing, thereby avoiding the installation of a large platform assembly 20 at the hub access structure 14. Therefore, it is sufficient that the first platform 21 extends from the hub access structure 14 to the radial position of the fastening device circle 13 in a direction substantially perpendicular to the axial direction 6, that is, along the radius of the main bearing reinforcement plate 10, to reach all the fastening devices 12 on the fastening device circle 13. Once the worker has completed the maintenance of the fastening devices 12 in the section accessible by the platform assembly 20, the main bearing can be rotated so that the worker can reach the next section of the fastening devices 12 in the fastening device circle 13 without repositioning the platform assembly 20.

[0114] Figure 3 and Figure 4 The vertical and horizontal positions of the platform assembly 20 are shown. The transition between the two positions can be accomplished by a rotation system 36 such as a hinge. Both positions can be the parked state or the first state 27 of the platform assembly 20. The selected position of the first state 27 depends on the design of the hub 4 and the rotating parts of the hub 4, and one or the other or an intermediate position between the two positions can be selected as the parked state or the first state 27 to avoid collision between the platform assembly 20 and the rotating parts of the hub 4.

[0115] Figure 5 Shows Figure 2 The wheel hub enters the structure 14 , wherein the platform assembly 20 includes a first platform 21 and a second platform 22 coupled to the first platform 21 .

[0116] The second platform 22 increases the working surface of the platform assembly 20 and allows workers to reach the blade bearings from the platform assembly 20 .

[0117] Figure 6 Another perspective view shows Figure 5 The platform assembly 20 is provided with a railing 23 mounted thereon and supported by a platform support 26. The platform assembly 20 is in a second state 28, in which the second platform 22 is coupled to the first platform 21 and extends in the axial direction 6 to increase the working surface within the hub 4.

[0118] As can be seen here, a worker can reach the blade bearing by walking on the working surface of the platform assembly 20 and perform maintenance work or installation work on the blade bearing or on the blade bearing reinforcement plate 11. To increase the safety of the platform assembly 20, a railing 23 is installed, which can be detached later.

[0119] The platform assembly 20 is supported by a platform support 26 mounted between a pitch lock 16 of the blade bearing and the second platform 22 of the platform assembly 20 .

[0120] In order to reduce the working surface of the platform assembly 20 extending in the axial direction 6, the second platform 22 can be separated from the first platform 21, such as Figure 7 The coupling is accomplished by pin coupling.

[0121] Another alternative to reduce the working surface of the platform assembly 20 is to stack the second platform 22 below the first platform 21, such as Figure 8 and Fig. 9 In these figures, a telescoping system 40 comprising a plurality of telescoping surface members 42 allows the working surface of the platform assembly 20 to be increased.

[0122] Figures 10 to 17 A second platform 22 is shown stacked below the first platform 21 , wherein the platform assembly 20 includes a rotation system 36 , a locking system, and a telescoping system 40 .

[0123] exist Fig.10 In the figure, the second platform 22 is stowed under the first platform 21 and secured by a locking pin 31, which cannot be seen in this perspective, and a locking socket 32. The figure shows the platform assembly 20 in its first state 27.

[0124] Figures 11 to 13The transition of the platform assembly 20 from the first state 27 to the second state 28 is shown, in which the rotation system 36 allows the second platform 22 to be rotated relative to the first platform 21 by means of the hinge 30. Thus, the second platform 22 is pivotably connected to the first platform 21, so that the second platform 22 rotates between a first position in which the second platform 22 is arranged below the first platform 21 and a second position in which the second platform 22 is in front of the first platform 21 and extends the working surface of the platform assembly 20 in the axial direction 6.

[0125] In order to further extend the working surface of the platform assembly 20 in the axial direction 6, the platform assembly 20 may include Fig.13 A telescoping system with a telescoping surface member 42 is shown in FIG.

[0126] Figures 14 to 17 A detailed view of the rotation of the second platform 22 relative to the first platform 21 of the platform assembly 20 by means of the rotation system 36 is shown.

[0127] The first platform 21 is rigidly coupled to the hub entry structure 14. The second platform 22 is pivotably coupled to the first platform 21 by means of a hinge 30 supported by a bushing 33.

[0128] The rotation system 36 comprises a spring 34 supported by a nut 35 at the hinge 30. The spring 34 pulls the second platform 22 towards the first platform 21.

[0129] Using spring 34 with the lock system including locking pin 31 and lock socket 32 ​​allows to keep second platform 22 fixed to first platform 21 in first state 27, second state 28 and third state 29 of platform assembly 20. This is because spring 34 constantly pulls second platform 22 against first platform 21.

[0130] In order to rotate the second platform 22 relative to the first platform 21, the second platform 22 is pushed to overcome the force of the spring 34, which releases the locking pin 31 from the lock socket 32 ​​and disengages the locking system. Then, the second platform 22 is rotated to the rotation position. Finally, the second platform 22 is released, and the force of the spring 34 brings the second platform 22 toward the first platform 21, and the locking pin 31 and the lock socket 32 ​​are combined together by the force of the spring 34, thereby locking the second platform 22 to the first platform 21.

[0131] As can be seen in the figures, the second platform 22 has a locking pin 31 and the first platform 21 has a locking socket 32, but the reverse is also possible.

[0132] The lock socket 32 ​​is a hole configured to receive the lock pin 31. The lock pin 31 is a cylindrical member having a longitudinal axis, a side surface, and a first end and a second end. The lock pin 31 is configured to be fitted in the lock socket 32.

[0133] The platform assembly 20 further comprises a telescopic system 40 arranged at the second platform 22, allowing the second platform 22 to be extended and increase the working surface by means of a telescopic surface member 42 and a telescopic arm 41. The telescopic system 40 rotates with the second platform 22 and is superimposed with the second platform 22 in the first state 27 of the platform assembly 20.

[0134] Figures 18 to 21 A telescoping system 40 of the platform assembly 20 for extending the working surface of the second platform 22 is shown.

[0135] The telescopic system 40 includes a plurality of telescopic arms 41 coupled to a plurality of telescopic surface members 42. By pulling the telescopic arm 41 of each telescopic surface member 42, the telescopic surface member 42 slides and extends the working surface of the second platform 22. In this case, with four telescopic surface members 42, the working surface of the second platform 22 is extended from Figure 18 to Figure 21 Four times.

[0136] Fig. 22 The platform assembly 20 is shown mounted at the hub access structure 14 in a parked position or first state 27, the platform assembly 20 including a damper 24 mounted between the platform assembly 20 and the hub access structure 14. The platform assembly 20 is in a vertical position.

[0137] By arranging the damper 24 between the platform assembly 20 and the hub access structure 14 , which are both fixed components, this has the advantage that the damper 24 does not have to be removed during operation of the wind turbine 1 .

[0138] Fig.23 The platform assembly 20 is shown in a horizontal position with a damper 24 mounted between the platform assembly 20 and the hub access structure 14. The damper 24 facilitates rotation of the platform assembly 20 from a horizontal position to a vertical position and vice versa.

[0139] Fig.24 The platform assembly 20 is shown in a third state 29 at an inclination angle 25. This is the position of the platform assembly 20 during installation or maintenance of the blade bearing, wherein the platform assembly 20 is fixed in this temporary position to be able to rotate the hub 4 without parts of the hub 4 colliding with the platform assembly 20.

[0140] The railing 23 may be left attached to the platform assembly 20 in this position, which reduces installation time.

[0141] The platform assembly 20 is supported by the damper 24 in this position.

[0142] Fig.25Attachment of the platform assembly 20 is shown with the aid of a support bracket 50. The support bracket 50 includes a support bracket pin 51 coupled to the platform assembly 20 and a support bracket socket 52 coupled to the main bearing reinforcement plate 10. When the first platform 21 is in a horizontal position, the use of the support bracket 50 to support the platform assembly 20 increases the stability of the platform assembly 20 and helps to secure the platform assembly 20 to the main bearing.

[0143] Figures 26 to 28 The main bearing reinforcement plate 10 is shown in an inclined position, ie at a certain angle to the vertical position. This is a common design for main bearings.

[0144] exist Fig.26 , the platform assembly 20 is in a horizontal position, wherein the platform assembly 20 is coupled to the main bearing reinforcement plate 10 by means of the support bracket 50. After the platform assembly 20 is supported by means of the support bracket 50, the second platform 22 of the platform assembly 20 can be extended to the second state 28 along the axial direction 6. When the platform assembly 20 or at least the first platform 21 of the platform assembly 20 is in a horizontal position, the platform assembly 20 is fixed by the support bracket 50 for workers to work on the working surface of the platform assembly 20.

[0145] Fig. 27 and 28 A schematic diagram of the vertical position of the platform assembly 20 is shown, wherein the platform assembly 20 is separated from the main bearing reinforcement plate 10 and the main bearing reinforcement plate 10 is rotated. This is the case when the platform assembly 20 is in the first state 27, wherein the second platform 22 is separated from the first platform 21, or as shown in this figure, is stowed under the first platform 21 to limit the surface of the platform assembly 20 within the hub 4.

[0146] like Fig.28 As shown in FIG, due to the inclined main bearing reinforcement plate 10, when the platform assembly 20 is in the vertical position, there is a gap between the support bracket pin 51 and the support bracket socket 52, that is, there is a gap between the platform assembly 20 and the main bearing, which avoids the collision between the support bracket pin 51 and the support bracket socket 52 when the main bearing rotates with the wheel hub 4. Due to the schematic nature of the figure, no gap is shown between the wheel hub entry structure 14 and the main bearing reinforcement plate 10. However, during the design of the wheel hub entry structure 14, care should be taken so that neither the main bearing reinforcement plate 10 nor the support bracket socket 52 will collide with the wheel hub entry structure 14, for example by shifting the step of the wheel hub entry structure 14 in the axial direction 6.

[0147] A damper 24 may also be installed between the platform assembly 20 and the hub entry structure 14 , which is not shown here.

[0148] Reference numerals list

[0149] 1. Wind Turbine

[0150] 2 Tower

[0151] 3 Cabin

[0152] 4 wheels

[0153] 5 blades

[0154] 6 Axial direction

[0155] 10Main bearing reinforcement plate

[0156] 11 Blade bearing reinforcement plate

[0157] 12 Fastening device

[0158] 13 Fastening means circle

[0159] 14Hub access structure

[0160] 15 Main bearing reinforcement plate opening

[0161] 16 Pitch lock

[0162] 20 Platform Components

[0163] 21 First Platform

[0164] 22 Second Platform

[0165] 23 Railing

[0166] 24 Damper

[0167] 25 Tilt Angle

[0168] 26 Platform support

[0169] 27 First State

[0170] 28 Second State

[0171] 29 Third State

[0172] 30 hinges

[0173] 31 Locking pin

[0174] 32 lock socket

[0175] 33 Bushing

[0176] 34 Spring

[0177] 35 Nut

[0178] 36 Rotation System

[0179] 40 telescopic system

[0180] 41 Telescopic arm

[0181] 42 Telescopic surface member

[0182] 50 support bracket

[0183] 51 Support bracket pin

[0184] 52 Support bracket socket.

Claims

1. A platform assembly (20) for a hub (4) of a wind turbine (1), configured to provide a working surface within the hub (4), characterized in that: The platform assembly (20) comprises a first platform (21) coupled to a hub access structure (14), wherein the hub access structure (14) extends in an axial direction (6) between a nacelle (3) and the hub (4) of the wind turbine (1) and provides access from the nacelle (3) to the hub (4), wherein the platform assembly (20) further comprises a second platform (22) configured to be coupled to the first platform (21), wherein the second platform (22) is configured to be positioned in such a manner that a surface of the second platform (22) extends substantially in the axial direction (6), and wherein the platform assembly (20) has a third state (29), in which the platform assembly (20) moves between a horizontal position and a vertical position at an inclination angle (25) in order to rotate the hub (4) without causing the hub (4) to collide with the platform assembly (20).

2. The platform assembly (20) according to claim 1, characterized in that: The first platform (21) extends in a direction substantially perpendicular to the axial direction (6).

3. The platform assembly (20) according to claim 1, characterized in that: The platform assembly (20) comprises a telescoping system (40) for moving the second platform from a stowed position to an extended position, in which the surface of the second platform (22) extends substantially along the axial direction (6).

4. The platform assembly (20) according to claim 3, characterized in that: The telescopic system (40) comprises a telescopic arm (41) and a telescopic surface member (42).

5. The platform assembly (20) according to claim 1, characterized in that: The platform assembly (20) includes a rotation system (36) for rotating the second platform (22) relative to the first platform (21).

6. The platform assembly (20) according to claim 5, characterized in that: The rotation system (36) includes a hinge (30) for rotational movement and a locking pin (31) and a locking socket (32) for fixing the second platform (22) in a stowed position and / or a rotated position.

7. The platform assembly (20) according to claim 1, characterized in that: When the wheel hub (4) rotates, the platform assembly (20) has a first state (27), in which the second platform (22) is separated from the first platform (21) or retracted above, below or in front of the first platform (21) to limit the surface of the platform assembly (20) within the wheel hub (4).

8. The platform assembly (20) according to claim 7, characterized in that: When the platform assembly (20) is in the first state (27), the first platform (21) is movable between a horizontal position and a vertical position.

9. The platform assembly (20) according to claim 7, characterized in that: The platform assembly (20) has a second state (28), in which the second platform (22) is coupled to the first platform (21), wherein the second platform (22) extends along the axial direction (6) to increase the working surface within the hub (4).

10. The platform assembly (20) according to claim 9, characterized in that The second platform (22) includes a platform support (26) configured to support the platform in the second state (28).

11. The platform assembly (20) according to any one of claims 1 to 10, characterized in that: The platform assembly (20) also includes a handrail (23).

12. The platform assembly (20) according to any one of claims 1 to 10, characterized in that: The platform assembly (20) also includes a damper (24) configured to absorb impact pulses.

13. A method for increasing a working surface in a hub (4) by means of a platform assembly (20) according to any one of claims 9-10, the method comprising the step of rotating the second platform (22) relative to the first platform (21) from the first state (27) to the second state (28).

Images