Drive train of a wind turbine

Abstract

The invention relates to a drive train (1) of a wind turbine, comprising a rotor (2) with a shaft (3), a main bearing (4) supporting the shaft (3), a gearbox (5) which is connected to the shaft (3), and a generator (6) connected to the gearbox (5). In order to subject the gearbox to the lowest possible load even if the main bearing does not ensure precise mounting of the shaft, the invention provides that the gearbox (5) and the generator (6) are elastically mounted relative to the main bearing (4), such that the gearbox (5) and the generator (6) can perform compensating movements relative to the main bearing (4) in the axial direction (a) and / or radial direction (r) to the shaft (3) and / or pivoting movements about an axis perpendicular to the axial direction (a).

Description

Field of the invention

[0001] The invention relates to a drive train of a wind turbine, comprising a rotor with a shaft, a main bearing supporting the shaft, a gearbox connected to the shaft, and a generator connected to the gearbox.

[0002] Such drive trains represent the classic design for wind turbines. The rotor and its rotor blades are connected to a shaft mounted in the main bearing of the wind turbine. The shaft passes through the main bearing and is connected to the gearbox, which in turn connects to the generator.

[0003] The main bearing and the gearbox (or its housing) are usually firmly bolted together. The disadvantage is that if the bearings are not precisely aligned or if the shaft is not precisely guided by the main bearing, the gearbox is subjected to bending stress due to the rigid connection to the shaft, which is detrimental to numerous gearbox components and thus reduces their service life. Summary of the invention

[0004] The invention is therefore based on the object of designing a drive train of the generic type in such a way that the transmission is exposed to the lowest possible load even if the main bearing does not ensure precise mounting of the shaft.

[0005] The solution to this problem by the invention provides that the gearbox and the generator are elastically mounted relative to the main bearing, so that the gearbox and the generator can perform compensating movements relative to the main bearing in the axial and / or radial direction to the shaft and / or pivoting movements about an axis perpendicular to the axial direction.

[0006] Accordingly, as a result of the elastic bearing, the gearbox including the generator should be able to move axially (in the axial direction) and / or laterally and / or rotationally relative to the main bearing around an axis that is perpendicular to the axial direction.

[0007] A preferred embodiment of the invention provides for the main bearing to be a hydrodynamic plain bearing. Such bearings are an advantageous alternative to rolling bearings, which are typically used as main bearings in wind turbines. A hydrodynamic plain bearing advantageously allows for bearing replacement on the tower without disassembling the rotor.

[0008] A preferred design for such a bearing provides for bearing segments (i.e., segmented bearing rings) in the circumferential direction. Particularly in very large wind turbines, segmented hydrodynamic plain bearings have the advantage that very large forging and hardening facilities are not required for the production of the bearing parts, and the transport of the bearing segments is much easier.

[0009] The gearbox and / or generator can be connected to a torque support, which prevents rotation of the gearbox and / or generator around the shaft's axis of rotation. This reliably supports the torque generated despite the gearbox or generator's elastic mounting.

[0010] The gearbox and the generator are preferably firmly connected to each other.

[0011] The main bearing is preferably connected to the gearbox exclusively via the shaft.

[0012] The main bearing is preferably fixedly mounted, in particular firmly bolted, on a support (i.e., on a platform in the tower). Meanwhile, elastic elements are preferably arranged between the support and the gearbox and / or the generator.

[0013] The elastic elements can be springs, especially coil springs. Blocks made of elastomer material are also possible.

[0014] Preferably, at least three, particularly preferably at least four, elastic elements are arranged between the carrier and the transmission; these can be arranged in a triangular or rectangular arrangement when viewed from above. The combination consisting of transmission and generator can also be mounted with three, four, or more elastic elements.

[0015] Hydrodynamic plain bearings are currently rarely used as main bearings for wind turbines. However, for the reasons mentioned above, they can be very advantageous for this application. However, with such bearings, the shaft can usually only be supported with less precision than with rolling bearings. This generally leads to greater bending loads on the (gearbox input) shaft. The proposed invention can effectively counteract this disadvantage.

[0016] If the gearbox and generator are free in all degrees of freedom – except rotation around the shaft axis – (i.e., especially in the axial and radial directions of the shaft), bending loads on the (gearbox input) shaft can be prevented. The gearbox and generator then follow the (minor) tilting and displacement of the shaft. The torque arm prevents the gearbox and generator from rotating around the shaft axis, allowing the output torque to be absorbed.

[0017] The weight of the gearbox and generator is supported by the elastic elements, so no (weight) forces are exerted on the shaft. This is unproblematic, as these are static loads that can be absorbed by the elastic elements.

[0018] The proposed concept therefore stipulates that the gearbox or its housing is not bolted to the main bearing or its housing, so that only the (rotor) shaft forms the connection between the main bearing and the gearbox (i.e., a rigid connection exists only between the shaft supported by the main bearing and the gearbox input shaft). Due to the elastic mounting of the gearbox and generator, minor tilting or misalignment movements do not lead to mechanical stress on the gearbox, as the gearbox can follow these movements thanks to the elastic mounting. Accordingly, the gearbox and generator can follow small tilting and displacement movements of the shaft without significant resistance forces. Short description of the drawings

[0019] The drawings illustrate an embodiment of the invention. They show: Fig. 1 schematically shows a side view of the drive train of a wind turbine according to the state of the art, Fig. 2 schematically shows in side view the drive train of the wind turbine according to Fig. 1 in an embodiment according to the invention and Fig. 3 schematically shows the generator, seen in the axial direction of the shaft, which is provided with a torque support. Detailed description of the drawings

[0020] In Fig. Figure 1 shows a diagram of a wind turbine drive train 1, as is known in the art. The rotor 2 with the rotor blades is connected to a shaft 3. The shaft 3 is mounted in a main bearing 4. The shaft 3 passes through the main bearing 4 and is connected to a gearbox 5. The figures do not differentiate between the fact that the shaft 3 does not usually pass through the main bearing 4 and enter the gearbox 5 in one piece, but rather the shaft section emerging from the main bearing 4 is firmly connected to a gearbox input shaft. A generator 6 for generating electrical energy is located behind the gearbox 5.

[0021] Main bearing 4, gearbox 5 and generator 6 are mounted on a carrier 8. Indicated in Fig. 1 also shows that the respective housings of the main bearing 4, the gearbox 5, and the generator 6 are firmly connected, i.e., bolted, to each other. The support 8 is formed by a platform located in the tower of the wind turbine.

[0022] In Fig. An embodiment of the invention is outlined in Figure 2. The structure of the drive train 1 shown here generally corresponds to that according to Fig. 1.

[0023] In contrast to the previously known solution, however, it is now provided that only the main bearing 4 is fixedly or rigidly mounted (screwed) on the carrier 8. However, it can be seen that both the transmission 5 and the generator 6 are not rigidly mounted on the carrier 8, but rather by means of elastic elements 9.

[0024] The elastic elements 9 are designed as helical springs and dimensioned to support the weight of the gearbox 5 and generator 6. Furthermore, the elements 9 prevent any tilting or displacement movements of the shaft 3 that may occur due to insufficiently precise mounting by the main bearing 4 from being directly transmitted to the gearbox 5. Rather, the elements 9 ensure that the gearbox 5 and generator 6 can perform appropriate compensating movements, so that the components in the gearbox, in particular, are not subjected to excessive loads.

[0025] In Fig. 2 shows the axial direction a and the radial direction r relative to the shaft 3. Movements of the gearbox 5 including the generator 6 relative to the carrier 8 can occur in these directions in order to compensate for said bearing errors.

[0026] Accordingly, the gearbox 5 and generator 6 are no longer rigidly arranged, so that precautions are useful to absorb the torque of the shaft 3, which is introduced into the gearbox 5.

[0027] In Fig. 3 shows a solution in which the generator 6—a similar arrangement can, of course, also be provided additionally or alternatively with respect to the transmission 5—is connected to a torque support 7. This is connected on the one hand to the generator 6 and on the other hand to the carrier 8, so that a torque introduced into the transmission 5 or the generator 6 can be supported.

[0028] In the embodiment according to Fig. 3, the torque support 7 is realized by two rods, one of which is fixedly attached to the generator 6; the rods are connected to each other in an articulated manner, with the rod not connected to the generator 6 being mounted in an articulated manner on the support 8. List of reference symbols 1 drivetrain 2 rotors 3 Wave 4 main bearings 5 gearboxes 6 Generator 7 Torque support 8 supports (platform) 9 elastic element (spring) a axial direction r radial direction

Claims

[1] Drive train (1) of a wind turbine, comprising a rotor (2) with a shaft (3), a main bearing (4) supporting the shaft (3), a gearbox (5) which is connected to the shaft (3), and a generator (6) connected to the gearbox (5), characterized by that the gearbox (5) and the generator (6) are elastically mounted relative to the main bearing (4), so that the gearbox (5) and the generator (6) can carry out compensating movements relative to the main bearing (4) in the axial direction (a) and / or radial direction (r) to the shaft (3) and / or pivoting movements about an axis perpendicular to the axial direction (a). [2] Drive train according to claim 1, characterized by that the main bearing (4) is a hydrodynamic plain bearing. [3] Drive train according to claim 2, characterized by that the main bearing (4) has bearing rings segmented in the circumferential direction. [4] Drive train according to one of claims 1 to 3, characterized bythat the gearbox (5) and / or the generator (6) is connected to a torque support (7) which prevents rotation of the gearbox (5) and / or the generator (6) about the axis of rotation of the shaft (3). [5] Drive train according to one of claims 1 to 4, characterized by that the gearbox (5) and the generator (6) are firmly connected to each other. [6] Drive train according to one of claims 1 to 5, characterized by that the main bearing (4) is firmly connected to the gearbox (5) exclusively via the shaft (3). [7] Drive train according to one of claims 1 to 6, characterized by that the main bearing (4) is fixedly arranged on a support (8), in particular is firmly screwed. [8] Drive train according to claim 7, characterized by that elastic elements (9) are arranged between the carrier (8) and the transmission (5) and / or the generator (6). [9] Drive train according to claim 8, characterized bythat the elastic elements (9) are springs, in particular helical springs, or blocks of elastomer material. [10] Drive train according to claim 8 or 9, characterized by that at least three, preferably at least four, elastic elements (9) are arranged between the carrier (8) and the gear (5), preferably in a triangular or rectangular arrangement when viewed in plan view.

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