Height-adjustable supporting mechanism for a supporting unit of a supporting system

Abstract

A height-adjustable supporting mechanism (10) for a supporting unit (11) of a supporting system (12) for supporting and securing a radially acting heavy load (13), in particular a tower of a wind power plant, wherein the supporting mechanism (10) comprises a spindle drive (14) with a spherical bearing, wherein the spherical bearing compensates for all angular errors occurring as a consequence of the radially acting heavy load (13) in relation to the longitudinal axis (X) of the spindle drive (14).

Description

[0001] Height-adjustable support mechanism for a support unit of a support system

[0002] The present invention relates to a height-adjustable support mechanism for a support unit of a support system for supporting and securing a radially acting heavy load, in particular a tower of a wind turbine. Such a mechanism is known, for example, from CN 204527377 U.

[0003] In recent years, wind energy has gained increasing importance as a clean and renewable new energy source in light of increasing environmental problems and energy scarcity. Wind energy has gradually become the largest and most mature power generation source among new energy technologies.

[0004] When constructing an offshore wind farm, it is first necessary to transport a large number of towers by a wind turbine installation vessel. Because the towers are each heavy and have a long, cylindrical structure, they are easily susceptible to toppling, necessitating the transport of the towers in a horizontal position. For the horizontal transport of the towers between land and the respective platform at sea, support systems are required. Their support mechanisms ensure safe transfer, lifting, and lowering of the towers.

[0005] The support system disclosed in CN 204527377 describes a hydraulically based support mechanism in which a tower is supported on a horizontally arranged load-bearing plate. The described support mechanism comprises two vertically arranged hydraulic cylinders, each driving a piston rod. The piston rods, in turn, are attached to the underside of the load-bearing plate, enabling the tower to be raised and lowered.

[0006] Wind turbine towers typically weigh between 500 and 4,000 tons, so the lifting cylinders must each generate enormous lifting force in order to raise, lower, or support the load-bearing plate and tower at a certain height.

[0007] Due to the fact that the two hydraulic cylinders are spaced apart from the center of the load-bearing plate and arranged orthogonally to it, and furthermore, the load-bearing plate is flat, but the tower has a cylindrical structure, high tilting moments act on the hydraulic cylinders, which must be absorbed in addition to the weight of the tower. These tilting moments cause an angular offset of the longitudinal axes of the respective hydraulic cylinders toward the center of the load-bearing plate, thus making safe and stable support or height adjustment of the tower impossible.

[0008] To overcome this problem, the support system disclosed in CN 204527377 uses large lifting cylinders to generate high lifting forces that counteract the tipping moments. However, this has the disadvantage that the support systems must be even larger when transporting larger and heavier towers, thus taking up more space on the transport vessels or the respective platform at sea. This, in turn, leads to increased manufacturing and maintenance costs.

[0009] A major disadvantage of the support mechanism, however, is that it is based on a hydraulic pressure principle and is not suitable for supporting such a heavy load. The mechanism loses its functionality in the event of a power failure or a hydraulic pump failure due to a leak. Without the lifting force generated by the hydraulic pump, the tower can neither be raised nor lowered, nor can it be supported at its original height. This could lead to a disaster on the transport vessel or the respective platform at sea, which requires a very high level of safety.

[0010] Based on this, the invention is based on the object of creating an improved support mechanism of the type mentioned above, avoiding the disadvantages of the prior art and advantageously developing the latter. In particular, radial forces acting on a cylindrical heavy load and the resulting tilting moments are to be absorbed and compensated, thus enabling reliable and safe lifting and lowering, especially at different heights, with increased stability.

[0011] A tipping moment is a left-handed or right-handed, in particular a positive or negative moment, which does not act around the main axis of the support mechanism.

[0012] Supporting the cylindrical heavy load here means holding or receiving the load in its position, which does not change relative to a horizontal reference point during the holding or receiving process. Any relative change relative to this horizontal reference point is understood as raising or lowering. According to the invention, this object is achieved by a support mechanism according to claim 1.

[0013] Specifically, the problem is solved by a height-adjustable support mechanism for a support unit of a support system for supporting and securing a radially acting heavy load, in particular a wind turbine tower. The support mechanism comprises a spindle drive with a spherical bearing, whereby the spherical bearing compensates for all angular errors relative to the longitudinal axis of the spindle drive that occur as a result of the radially acting heavy load.

[0014] The invention has the significant advantage that, thanks to the spherical bearing of the spindle drive, stabilized lifting and lowering, in particular, reliable support of a cylindrical heavy load, is possible at different heights. All tilting moments resulting from the radially acting heavy load are absorbed, thus compensating for and preventing misalignments. This significantly increases the operational safety factor.

[0015] A further advantage of the invention is that, due to the compensation of the tilting moments by the spherical bearings, it is no longer necessary to use larger support units to counteract the tilting moments. The support units and consequently the support system as a whole can thus be dimensioned more compactly, taking up less space on the transport ships or the respective platform at sea. Several support systems can therefore be set up side by side, allowing the number of towers per transport to be increased. This, in turn, leads to savings in transport costs.

[0016] Another advantage of the invention is that it eliminates the need for compressible and temperature-dependent hydraulic oil, the loss of which due to a leak can lead to system failure. Hydraulic systems under such high loads are subject to very high pressures, which must be controlled and balanced by a multitude of valves. Furthermore, the purity of the hydraulic oil must meet stringent requirements. The higher the pressure, the more viscous the hydraulic oil becomes, so even the smallest contaminants can lead to blockages and system failure.

[0017] Preferred embodiments of the invention are specified in the subclaims.

[0018] In a preferred embodiment, the support mechanism has a spherical bearing arrangement comprising a first bearing and a second bearing. The first bearing is advantageously an axial self-aligning bearing. The second bearing, on the other hand, is advantageously designed as at least one axial spherical roller bearing with a very high load-bearing capacity, which can have specially designed raceways and asymmetrical rollers. Particularly advantageously, two axial self-aligning roller bearings clamped against one another can be provided. This makes it possible to absorb both axial forces in one direction and radial forces with simultaneously acting axial forces. The forces are transferred from one raceway to the other at an angle to the bearing axis. Furthermore, the two bearings can each be designed to be angularly movable in order to absorb and compensate for misalignments, in particular dynamic or static misalignments, during lifting and lowering or during supporting.

[0019] According to an advantageous embodiment of the invention, the first bearing can have a retraction stop ring which can be preloaded via an elastomer spring relative to the axial self-aligning bearing in order to set a specific bearing preload

[0020] According to a further embodiment of the invention, the second bearing has two axial spherical roller bearings that can be clamped against each other.

[0021] In a further preferred embodiment, the support mechanism comprises a spindle drive with a spindle and a rotatably arranged spindle nut. The spindle and the spindle nut are engaged via a movement thread. The spindle drive is more reliable in operation than a hydraulic drive and is particularly suitable for precise height adjustment as well as for pressure and pivoting movements. Furthermore, the spindle drive is compact and cost-effective to manufacture. The spindle drive can be designed for either rotating or stationary operation. Rotating operation means that the spindle nut screws up and down along the movement thread and performs the lifting movement. Stationary operation means that a worm gear has a thread and converts the rotary movement into an axial movement around the spindle, whereby the spindle is secured against twisting.

[0022] The spindle drive preferably has a first support element and a second support element. The first support element is arranged above the spindle nut, and the second support element is arranged below it. The two support elements enable the introduction and absorption of the axial and bending forces that lead to spindle deflection, thus providing efficient support and stabilization of the spindle during operation. Furthermore, they help minimize vibrations to ensure smooth running.

[0023] In order to withstand the high axial forces along the main axis of the spindle drive during operation, the movement thread must be designed with a large pitch before it fails through shearing. A large pitch here means the distance, measured parallel to the main axis, between two adjacent, similarly directed thread flanks of the same thread. The movement thread is preferably designed as a trapezoidal thread. In cross-section, the profile of the trapezoidal thread, in contrast to a metric ISO thread, has the shape of an isosceles trapezoid with a flank angle of at least 30°. Due to this significantly thicker thread, the trapezoidal thread has a particularly high level of friction, so that the spindle drive is designed to be self-locking and self-locking. In other words, in contrast to the state of the art, in the event of a power failure or other error, unintentional, independent lifting or lowering is prevented.The trapezoidal thread prevents the heavy load from being lowered. Furthermore, the drive source, especially the electric motor, can be switched on only to adjust the lifting height of the heavy load, but switched off to support the heavy load at a specific height.

[0024] In a further preferred embodiment, the spindle drive comprises a high-pressure lubrication device for lubricating the spindle nut. Lubricating the spindle nut or spindle reduces the high friction and noise generated between the spindle nut and spindle due to the trapezoidal thread. Reducing friction, particularly the coefficient of friction, consequently reduces wear, which in turn extends the service life of the spindle nut or spindle. Furthermore, lubrication of the spindle nut increases the overall smoothness of the spindle drive and enables precise height adjustments, even at higher lifting speeds.

[0025] The high-pressure lubrication device preferably has a control device for monitoring the lubricant content in the high-pressure lubrication device. Monitoring the lubricant content ensures automated lubrication, so that a specific lubricant content, in particular a defined volume of lubricant per stroke and / or per unit of time, is released from the high-pressure lubrication device to lubricate the spindle nut or spindle. This ensures, on the one hand, that the spindle nut or spindle is sufficiently lubricated to enable optimal operation of the spindle drive. On the other hand, it prevents overlubrication.

[0026] In order to apply the lubricant to the interior of the spindle nut, in particular to the internal thread of the spindle nut or the external thread of the spindle, the spindle nut preferably has at least one lubricant channel running transversely to the main axis for introducing the lubricant. Due to the transverse arrangement of the lubricant channel, the amount of lubricant can be applied evenly and precisely to the external thread, in particular to one thread of the moving thread, depending on the position of the spindle nut.

[0027] Preferably, a high-pressure lubrication line can be provided for introducing a lubricant, which is guided externally next to the spindle drive via a telescopic lubrication line guide.

[0028] In a preferred embodiment, the spindle drive comprises a drive element. The drive element simply transmits the rotational movement generated by an external drive source, in particular a drive torque, directly to the spindle, thereby causing the spindle or spindle nut to rotate.

[0029] The drive element can preferably be connected to an electric motor. This includes both a synchronous and an asynchronous motor. The lifting height and lifting speed depend on the pitch of the drive screw and the speed of the applied drive torque. Due to the high axial forces along the main axis of the spindle drive caused by the weight of the heavy load, electric motors are particularly suitable because of their very high efficiency. With an electric motor, the drive torque and consequently the drive speed are available from the start, enabling precise lifting and lowering of the heavy load at all times.

[0030] Preferably, the spindle drive is sealed in the drive area by a sealing element that slides flexibly on the drive element. This prevents lubricant or other contaminants released from the high-pressure lubrication device during operation, for example, from entering the drive area via the drive element and contaminating the drive train, in particular the electric motor, and causing it to malfunction. In a further preferred embodiment, the spindle drive has a force measuring device. The force measuring device can measure both the axial forces acting along the main axis of the spindle drive due to the applied weight force and the tilting moments resulting from the radial forces, so that the lifting speed or lifting height of the spindle drive can be precisely adjusted depending on the acting forces.This is particularly advantageous when multiple spindle drives are spaced apart from one another around the circumference of the heavy load to lift, lower, or support the heavy load together. In other words, the heavy load can be supported by multiple spindle drives distributed over the circumference, so that in addition to compensating for the spherical bearings per spindle drive, radial forces acting on the spindle can also be balanced by the sum of all spindle drives. This enables even more stable lifting, lowering, or supporting.

[0031] In a further preferred embodiment, the spindle drive has a control device. The control device processes the signals sent by the force measuring device, allowing individual or multiple spindle drives to be controlled depending on the acting forces. For example, the lifting speed or lifting height of an individual spindle drive can be adjusted depending on or independently of the other spindle drives. The spindle drives can thus be operated synchronously or asynchronously.

[0032] The invention will be explained in more detail below with reference to the accompanying drawings. The illustrated embodiments represent examples of how the device according to the invention can be designed.

[0033] In these drawings

[0034] Fig. 1 : a cross-section of a support system with several support units. - io -

[0035] Fig. 2: a cross-section of a single spindle drive in the retracted state,

[0036] Fig. 3: a cross-section through an upper bearing of the spindle drive according to Fig. 2 and

[0037] Fig. 4 shows a cross-section through a lower bearing of the spindle drive according to Fig. 2.

[0038] Fig. 1 shows a support system 12 with several support units 11 for lifting, lowering, and supporting a radially acting heavy load 13, in particular a tower of a wind turbine. Specifically, the support system 12 has four support units 11, each with its own spindle drive 14, wherein these four support units 11 are arranged along a circumference of an inner support surface 12a of the support system.

[0039] 12 are arranged. The support units 11 are integrated in the support system 12 and firmly connected to the support system 12.

[0040] The support units 11 are arranged along the inner support surface 12a in such a way that the main axes Xi of the spindle drives 14i of the inner support units 11i form an angle α and the main axes Xa of the spindle drives 14a of the support units 11a form an angle β, relative to a vertical axis V of the heavy load 13. In other words, the support units 11 and consequently the spindle drives 14 are arranged at a distance from one another both along the circumference of the inner support surface 12a and along the circumference of the heavy load 13, wherein the main axes Xi of the inner spindle drives 14i are angled by an angle α and the main axes Xa of the outer spindle drives 14a are angled by an angle β relative to the vertical axis V of the heavy load 13. The two angles α and β depend on the weight and diameter of the heavy load to be supported and can vary depending on the load.This means the inner and outer spindle drives 14i and 14a can be spaced closer to each other or further apart from each other around the circumference of the heavy load 13 in order to support the heavy load.

[0041] 13 in such a way that the radially acting forces due to the heavy load 13 are optimally compensated by the spherical bearings of the individual spindle drives 14. Each support unit 11 comprises a modular load-bearing unit 11L, each having a load-bearing carrier 11T, wherein the spindle drive 14 of each support unit 11 is connected to the associated load-bearing carrier 11T directly or indirectly by a coupling element, such that the load-bearing carrier 11T can be axially displaced by a specific stroke along the main axis X of the respective spindle drive 14. In other words, the load-bearing carrier 11T is connected to the spindle drive 14 and is extended and retracted by the spindle drive 14 to lift, lower, and support the heavy load 13.

[0042] In Fig. 1, the four load-carrying beams 11aT are shown in an extended state by a specific stroke, and the four inner load-carrying beams 11iT are shown in a retracted state. The retracted and extended state of the individual load-carrying beams 11T depends on the angles α and β, and in particular on the weight and diameter of the heavy load 13 to be supported. Each load-carrying beam 11T can be displaced axially along its main axis by a specific stroke, depending on or independently of the other load-carrying beams 11T.

[0043] Each load-bearing support 11T comprises a load-bearing surface 11F, on which the heavy load 13 rests directly. The load-bearing surface 11F has a concave shape, in particular a shape adapted to the diameter or circumference of the heavy load 13 to be supported, so that at least one radial force FX of the heavy load 13 is introduced along the main axis X of the spindle drive 14. All other radial forces F acting as a result of the heavy load 13 that do not act along the main axis X of the spindle drive 14 are absorbed and compensated by the spherical bearing.

[0044] Fig. 2 shows a cross-section of a single spindle drive 14 in the retracted state. The spindle drive 14 essentially comprises a housing 16 with a rectangular cross-section, a spindle 17, a spindle nut 18, which engages with the spindle 17 via a movement thread 19, a first bearing 30, a second bearing 40, and a drive element 26.

[0045] The spindle drive 14 is housed in a substantially box-shaped outer housing 27. The likewise box-shaped housing 16 of the spindle drive 14 is slidably mounted in the box-shaped outer housing 27 via slide rails. The box-shaped outer housing 27 is firmly connected to the support unit 11 via a flange connection 27a, so that each support unit 11 comprises a box-shaped outer housing 27, each with a spindle drive 14 (see Fig. 1).

[0046] The spindle nut 18 is surrounded by a cylindrical protective cover 23. The spindle nut 18 has lubricant lines 25 for introducing a lubricant, which are guided via laterally arranged telescopic lubrication line guides, thus ensuring secure guidance of the lubricant line. A high-pressure-resistant adhesive oil can preferably be used as the lubricant. The lubricant lines are connected to a high-pressure lubrication device (not shown here). By lubricating the spindle nut 18 or the spindle 17, the high friction and noise generated between the spindle nut 18 and the spindle 17 due to the trapezoidal thread are reduced. This enables precise height adjustments.

[0047] The high-pressure lubricant device preferably has a control device (not shown here) for monitoring a lubricant content in the high-pressure lubricant device, thus ensuring automated lubrication of the spindle nut 18 or the spindle 17. In particular, a specific lubricant content, in particular a volume of lubricant defined per stroke and / or per unit of time, can be dispensed from the high-pressure lubricant device for lubricating the spindle nut 18 or the spindle 17. In the illustrated embodiment, the movement thread 19 is designed as a trapezoidal thread with a thread pitch of 28 mm and a nominal diameter of 320 mm. It is conceivable that the trapezoidal thread, in a further preferred embodiment, has a higher or lower thread pitch or nominal diameter depending on the heavy load to be absorbed.The thick trapezoidal thread has a particularly high friction, so that the spindle drive 14 is designed to be self-locking and self-locking.

[0048] The spherical bearing comprises the first bearing 30 and the second bearing 40. The first bearing 30 is designed as an axial self-aligning bearing and absorbs forces acting in the Z direction at least orthogonal to the longitudinal axis X of the spindle drive 14. The second bearing 40 is designed as a multiple axial spherical roller bearing and absorbs forces acting in the Y direction at least orthogonal to the longitudinal axis X of the spindle drive 14. The first bearing 30 is arranged below a support element 20 and above the spindle nut 18. The second bearing 40 is arranged below the spindle nut 18.

[0049] The structure of the first bearing 30, which represents the upper bearing according to Figure 2, is shown in more detail in Figure 3. This bearing incorporates an axial self-aligning bearing 32. A first support element is designated by 20. The axial self-aligning bearing 32 can be preloaded via a retraction stop ring 34 using an interposed elastomer spring 36. The preload compensates for forces that are not introduced at an angle to the main spindle 17. The bearing clearance of the bearing 30 can be adjusted, effectively preventing radial deflection from the spherical bearing shell. Finally, the retraction protection provided by the retraction stop ring 34 absorbs the lifting forces.

[0050] Figure 3 also shows the spindle nut 18, which is indirectly connected to the axial self-aligning bearing 32 via an anti-twist device 38. The spindle nut is made of bronze and is therefore seawater-resistant. This enables particularly advantageous maritime use. A lubricant connection 39 is provided on the side of the spindle nut 18. The more precise structure of the second bearing 40, which represents the lower bearing, can be seen in Figure 4. The bearing 40 has a first axial self-aligning roller bearing 42 and a second axial self-aligning roller bearing 44, with the second axial self-aligning roller bearing serving to precisely clamp the bearing system and to absorb lift-off forces. A nut 46 is provided for clamping and adjusting the bearing clearance. This arrangement can absorb retraction forces of approximately 100 kN.Precise adjustment of the bearing clearance is necessary because excessive clearance in bearing 40 would result in radial deflection of the spherical bearing shells. 48 designates a special mechanical seal. 49 designates a bearing housing.

[0051] The drive element 26 is firmly connected to the electric motor 26a by a flange connection and to the spindle 17 by a screw connection. The electric motor 26a is preferably designed as a geared motor and has a drive power of at least 7.5 kW in order to generate a drive torque between 17,800 Nm and 25,000 Nm. It is conceivable that, in a further preferred embodiment, the electric motor may have higher or lower power values. The electric motor can be designed as either a synchronous or an asynchronous motor.

[0052] In the illustrated embodiment, the spindle drive 14 is designed to rotate, so that the lifting movement is carried out as a result of the screwing and unscrewing of the spindle nut 18 along the movement thread 19. It is conceivable that the spindle drive 14 is designed to be vertical in a further preferred embodiment, so that the lifting movement is carried out as a result of a conversion of a rotary movement into axial movement around the spindle 17 by a worm gear with a thread, wherein the spindle 17 is secured against twisting.

[0053] Specifically, in the illustrated embodiment, the lifting movement is carried out in such a way that a rotational movement, in particular a drive torque, is generated by an external drive source, in particular the electric motor 26a, which is transmitted to the spindle 17 by the drive element 26 and sets the spindle 17 in rotation. Since the spindle drive 14 is designed to be rotating and the spindle nut 18 is engaged with the spindle 17 via the movement thread 19, the spindle nut 18 screws up along the movement thread 19 during lifting, in particular a positive stroke, and unscrews along the movement thread 19 during lowering, in particular a negative stroke.

[0054] During a positive stroke movement, the spindle nut 18 screws along the movement thread 19 and moves the first bearing 30 and with it the housing 16 relative to the outer housing 27. The spindle drive 14 can be connected to the associated load-bearing carrier 11T directly or indirectly by a coupling element 31, so that the load-bearing carrier 11T can be positively displaced axially by a certain stroke along the main axis X of the spindle drive 14 by the telescopic retraction and extension of the housing 16.

[0055] During a negative stroke movement, the force flow occurs in the same way, with the spindle nut 18 unscrewing along the movement thread 19.

[0056] When holding or supporting the heavy load, the force flow occurs in the same way as in a negative lifting movement, whereby the high friction due to the trapezoidal thread supports the spindle nut 18 and consequently the cylindrical inner housing 16 being self-locking in the supported height position.

[0057] At all times, the spindle 17 is supported and mounted by the spherical bearing. This means that both the axial forces FX acting along the main axis X and the radial forces F, as well as the resulting tilting moments, are absorbed by the spherical bearing, thus compensating for and preventing misalignments. This enables stabilized lifting and lowering, particularly reliable support of the cylindrical heavy load 13, at different heights.

Claims

Claims Height-adjustable support mechanism (10) for a support unit (11) of a support system (12) for supporting and securing a radially acting heavy load (13), in particular a tower of a wind turbine, characterized in that the support mechanism (10) comprises a spindle drive (14) with a spherical bearing, wherein the spherical bearing compensates for all angular errors occurring as a result of the radially acting heavy load (13) relative to the longitudinal axis (X) of the spindle drive (14). Support mechanism according to claim 1, characterized in that the spherical bearing comprises a first bearing (30) and a second bearing (40), wherein the first bearing (30) is an axial self-aligning bearing and wherein the second bearing (40) has at least one axial self-aligning roller bearing and preferably two axial self-aligning roller bearings. Support mechanism according to one of the preceding claims, characterized in that the first bearing (40) has a retraction stop ring which can be preloaded via an elastomer spring relative to the axial spherical bearing in order to set a specific bearing preload. Support mechanism according to one of the preceding claims, characterized in that the second bearing (30) has two axial spherical roller bearings which can be braced against one another. Support mechanism according to one of the preceding claims, characterized in that the spindle drive (13) comprises a spindle (17) and a rotatably arranged spindle nut (18) which engages with the spindle (17) via a movement thread (19). Support mechanism according to one of the preceding claims, characterized in that the movement thread (19) is designed as a trapezoidal thread.Support mechanism according to one of the preceding claims, characterized in that the spindle drive (14) comprises a high-pressure lubricant device for lubricating the spindle nut (18). Support mechanism according to one of the preceding claims, characterized in that the high-pressure lubricant supply device has a control device for monitoring a lubricant content in the high-pressure lubricant device. Support mechanism according to one of the preceding claims. characterized in that a high-pressure lubrication line is provided for introducing a lubricant, which is guided externally next to the spindle drive (14) via a telescopic lubrication line guide. Support mechanism according to one of the preceding claims, characterized in that the spindle drive (14) comprises a drive element (26) for transmitting a rotary movement. Support mechanism according to one of the preceding claims, characterized in that the drive element (26) is connectable to an electric motor (26a). Support mechanism according to one of the preceding claims, characterized in that the spindle drive (14) is sealed in the drive region by a sealing element that slides flexibly on the drive element (26). Support mechanism according to one of the preceding claims, characterized in that the spindle drive (14) has a force measuring device.Support mechanism according to one of the preceding claims, characterized in that the spindle drive (14) has a control device.

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