DE102024108257B4 - Main bearing of a wind turbine - Google Patents

Abstract

The invention relates to a main bearing (1) of a wind turbine, wherein the main bearing (1) is designed as a plain bearing, wherein the outer bearing ring (2) of the plain bearing consists of a number of bearing segments (3, 4) arranged around the circumference of the outer bearing ring (2), and wherein the bearing segments (3, 4) have a bearing surface (5, 6) which is set or adjustable to a defined radial position (r ₁ , r ₂ ). To further develop a main bearing designed as a sliding bearing for a wind turbine in such a way as to reduce friction and thus wear during start-up and stop-down processes, the invention provides that the bearing segments (3, 4) consist of a first group and a second group, wherein the bearing segments (3) of the first group are set or adjustable to a first radial position (r ₁ ) and wherein the bearing segments (3) of the first group have a first spring elasticity in the radial direction (r) and wherein the bearing segments (4) of the second group are set or adjustable to a second radial position (r ₂ ) which differs from the first radial position (r ₁ ) and wherein the bearing segments (4) of the second group have a second spring elasticity in the radial direction (r) which differs from the first spring elasticity, wherein the first radial position (r ₁ ) is greater than the second radial position (r ₂ ) and wherein the first spring elasticity is greater than the second spring elasticity.

Description

Field of invention

The invention relates to a main bearing of a wind turbine, wherein the main bearing is designed as a plain bearing, wherein the outer bearing ring of the plain bearing consists of a number of bearing segments arranged around the circumference of the outer bearing ring, and wherein the bearing segments have a bearing surface that is set or adjustable to a defined radial position.

A generic main bearing for a wind turbine is derived from the US 2020/0173425 A1 known.

For supporting the rotor of a wind turbine, hydrodynamic plain bearings are an attractive alternative to the rolling bearings that are commonly used. These plain bearings allow for bearing replacement on the tower without disassembling the rotor, which is very cost-effective. Another significant advantage of segmenting the outer ring of the bearing, particularly in very large wind turbines, is that such plain bearings do not require large forging and hardening facilities, and the segments are also easier to transport.

In the aforementioned previously known solution, the individual bearing segments of the outer ring are designed with regard to the expected maximum load and fixed in the position required by the design.

No special consideration is given to low load conditions.

The problem is that mixed friction occurs during start-up and stop-down processes in hydrodynamic plain bearings, causing a certain amount of wear on the sliding surfaces of the bearing segments. Furthermore, this introduces relatively high frictional torques into the structure. At low wind speeds, a correspondingly high frictional torque in the plain bearing can prevent the wind turbine from starting.

Due to a highly variable load direction, the individual segments of the sliding bearing are exposed to different loads and are sometimes not needed at all in certain load directions.

Various solutions for the design of a plain bearing are derived from the DE 10 2017 223 370 A1 , the US 2011/0188988 A1 , the US 2019/0195204 A1 and the WO 2019/120870 A1 known.

Summary of the invention

The invention is based on the objective of further developing a main bearing designed as a sliding bearing for a wind turbine in such a way that friction and thus wear during start-up and stop-down processes can be reduced. This should enable a longer service life for a bearing of this type.

The solution to this problem by the invention provides that the bearing segments consist of a first group and a second group, wherein the bearing segments of the first group are set or adjustable to a first radial position and wherein the bearing segments of the first group have a first spring elasticity in the radial direction and wherein the bearing segments of the second group are set or adjustable to a second radial position which is different from the first radial position and wherein the bearing segments of the second group have a second spring elasticity in the radial direction which is different from the first spring elasticity, wherein the first radial position is greater than the second radial position and wherein the first spring elasticity is greater than the second spring elasticity.

The aforementioned radial positions refer to the radial position of the bearing surfaces of the bearing segments to accommodate the component being supported, in particular the rotor of the wind turbine. A larger radial position means that the bearing surface of the bearing segment is located closer to the component being supported, specifically the rotor of the wind turbine. This refers to the radial distance of the bearing surface of the bearing segment from the housing part that accommodates the outer bearing ring.

Regarding spring elasticities, it should be noted that a higher spring elasticity value results in a greater spring deflection (in the radial direction) when a force (from the rotor) is applied. Higher spring elasticity therefore means that the spring constant or spring stiffness (measured in N/m) has a lower value than in the case of lower spring elasticity.

The difference between the first radial layer and the second radial layer is preferably between 0.1 mm and 5.0 mm.

The first spring elasticity is preferably at least 3 times, and preferably at least 5 times, greater than the second spring elasticity. Correspondingly, the spring constant in the case of the first spring elasticity is at least 3 times, and preferably at least 5 times, smaller. than the spring constant in the case of the second spring elasticity.

The bearing segments of the first group and the bearing segments of the second group are preferably arranged axially adjacent to one another. Alternatively, however, it is also possible for the bearing segments of the first group and the bearing segments of the second group to follow one another alternately in the circumferential direction. It is also possible that, in the circumferential direction, more than one bearing segment of the second group follows a bearing segment of the first group (or vice versa).

At least the bearing segments of a group preferably each consist of a support element arranged on a component made of elastomeric material, wherein the component made of elastomeric material is fixed to a housing part. In this case, the elasticity of at least one group of bearing segments is provided by the component made of elastomeric material.

A particularly preferred embodiment of the invention provides that the bearing segments of the first group are equipped with a fluid inlet to the bearing surface in order to create a hydrostatic bearing function. Accordingly, a hydrostatic bearing function is generated which, starting from a standstill of the rotor, ensures virtually frictionless bearing operation, thereby preventing wear.

Friction, and therefore the wear occurring during start-up and stop-down processes, can be significantly minimized by hydrostatic lubrication pockets in plain bearing segments. Plain bearing segments with hydrostatic lubrication pockets have a lower load-bearing capacity in normal wind turbine operation than plain bearing segments without hydrostatic lubrication pockets. This is advantageously utilized by combining hydrostatic and hydrodynamic lubrication pockets in the proposed design.

The bearing segments of the first group can be equipped with adjusting means for changing their first radial position. These adjusting means can comprise a hydraulic piston-cylinder system used for adjusting the first radial position. Alternatively, the adjusting means can also comprise a mechanical adjusting system, in particular a tappet, used for adjusting the first radial position. This design ensures that the bearing segments of the first group are retracted in their radial position towards the rotor once the motor has started; this is particularly advantageous when the bearing segments of the first group are designed as hydrostatic elements.

The proposed hydrodynamic plain bearing thus has a load-controlled sliding surface. An increasing sliding surface is created with increasing load, while the plain bearing segments with hydrostatic lubrication pockets – in addition to the plain bearing segments without hydrostatic lubrication pockets – ensure low wear during rotor start-up and shutdown.

Brief description of the drawings

• 1 schematisch in der geschnittenen Seitenansicht ein Hauptlager einer Windkraftanlage gemäß einer ersten Ausführungsform der Erfindung, wobei von dem zur Lagerung eingesetzten Gleitlager nur ein Teil dargestellt ist, und
• 2 schematisch in der geschnittenen Vorderansicht das Hauptlager gemäß einer zweiten Ausführungsform der Erfindung, wobei wiederum von dem zur Lagerung eingesetzten Gleitlager nur ein Teil dargestellt ist.

The drawings illustrate exemplary embodiments of the invention. They show:

• 1 schematically in a cutaway side view a main bearing of a wind turbine according to a first embodiment of the invention, wherein only a part of the sliding bearing used for the bearing is shown, and
• 2 schematically in the cutaway front view the main bearing according to a second embodiment of the invention, wherein again only a part of the sliding bearing used for support is shown.

Detailed description of the drawings

In 1 The main bearing 1 of a wind turbine is sketched, which is designed as a plain bearing. Bearing segments 3, 4 are arranged in a housing part 11, forming the outer bearing ring 2 and each having a bearing surface 5, 6. The bearing surfaces 5, 6 face the rotor of the wind turbine and, in particular, the shaft part 13 thereof, and support it. The bearing segments 3, 4 extend (as shown in 1 (not shown) around the entire circumference of the shaft part 13, so that the latter is fully supported.

Out of 1 It is evident that the bearing segments 3 and 4 consist of two groups. Bearing segments 3 form a first group, and bearing segments 4 form a second group. In the exemplary embodiment according to 1 The two groups 3, 4 are arranged next to each other in axial direction a and are attached in the housing part 11.

Furthermore, it can be seen that the surface of the bearing surfaces 5, 6 is arranged in different radial positions for the two groups 3 and 4. In this respect, the radial direction r is first noted, which in 1 is entered. In the case of bearing segments 3, i.e., in the case of the first group, a first radial position r ₁ is present, while in the case of bearing segments 4, i.e., in the case of the second group, a second radial position r ₂ is given. The two radial positions r ₁ , r ₂ are to be understood as being from the perspective of the housing part 11, as can be seen from the registered designation of the two radial positions.

The first radial layer _r1 is larger than the second radial layer _r2 . Accordingly, the surface of bearing surface 5 is closer to shaft part 13 than the surface of bearing surface 6, which is located somewhat further away from shaft part 13.

Furthermore, it can be seen that the bearing segments 3, 4 each consist of a support element 7 or 8, which can be provided with a sliding layer in the area of the bearing surface 5, 6 in a manner known per se. The support element 7, 8 is connected to a component 9 or 10, which consists of an elastomeric material and therefore has spring-like properties. By selecting a correspondingly different radial height of the component 9, 10, it is achieved that the spring elasticity of the bearing segment 3 and that of the bearing segment 4 are of different magnitudes, whereby the elasticity in the radial direction r is to be understood.

Since a component 9 is provided for the bearing segment 3, which has a larger extension in the radial direction r than in the case of the bearing segment 4, the bearing segment 3 has a first spring elasticity which is greater than the second spring elasticity (for the relevant definition, reference is made to the above explanations on the spring constant).

Thus, in the case of the exemplary embodiment, the main bearing forms according to 1 An axially split radial sliding bearing. This consists of two groups of bearing segments 3, 4 (also referred to as pads), which are set differently in their radial height and are mounted with different stiffness.

Bearing segment 3 is positioned higher (from the perspective of housing part 11), meaning it initially absorbs the load when shaft part 13 exerts forces on the outer bearing ring 2. Bearing segment 3 is mounted with significantly more elasticity compared to bearing segment 4. Consequently, as wind speed and the load increase, bearing segment 3 compresses until bearing segment 4 engages. Bearing segment 4 is mounted lower but with greater rigidity and then assumes the majority of the load.

The exemplary embodiment according to 2 This illustrates that instead of an axial offset of the bearing segments 3, 4, an offset in the circumferential direction U can also be provided. 2 Only three bearing segments are shown in total, namely one bearing segment 3 and two bearing segments 4, although of course bearing segments 3, 4 are arranged over the entire circumference of the shaft part 13.

In 2 It is also indicated (by a double arrow) that adjusting means 12 can be provided for the first radial position _r1 . This allows the bearing segments 3 to be moved back in their radial position after the rotor has started, so that the bearing load is predominantly absorbed by the bearing segments 4. The method by which the bearing segments 3 are adjusted in the radial direction r is essentially arbitrary. For example, tappets can be used for this purpose. This also allows the stiffness to be influenced.

This is particularly advantageous when 4 classic hydrodynamic segments are used for the bearing segments, while 3 hydrostatic sliding bearing segments are used for the sliding bearing segments.

In this case, it is advantageous to install sliding bearing segments 3 with hydrostatic lubrication pockets of greater height (first radial layer _r1 ) and more elastic mounting together with sliding bearing segments 4 without hydrostatic lubrication pockets of lesser height (second radial layer _r2 ) and less elastic mounting. During start-up operations under low wind loads, the hydrostatic sliding bearing segments 3 are primarily in contact. Under high wind loads, the elastically mounted sliding bearing segments 3 with hydrostatic lubrication pockets compress, and the more load-bearing sliding bearing segments 4 without hydrostatic lubrication pockets come into contact.

The sliding bearing segments 3 with hydrostatic lubrication pockets can, as explained, be mounted, for example, on hydraulic tappets or hydraulic cylinders, so that they can be extended for start and stop operations.

Reference symbol list

1

Main bearing of the wind turbine

2

Outer bearing ring

3

Storage segment

4

Storage segment

5

Storage area

6

Storage area

7

Support element

8

Support element

9

component

10

component

11

Housing part

12

Setting device for the first radial position

13

shaft part

a

axial direction

r

radial direction

U

Circumferential direction

r1

first radial layer

r2

second radial layer

Claims (10)

Main bearing (1) of a wind turbine, wherein the main bearing (1) is designed as a plain bearing, wherein the outer bearing ring (2) of the plain bearing consists of a number of bearing segments (3, 4) arranged around the circumference of the outer bearing ring (2), and wherein the bearing segments (3, 4) have a bearing surface (5, 6) that is set or adjustable to a defined radial position ( _r1 , _r2 ), characterized in that the bearing segments (3, 4) consist of a first group and a second group, wherein the bearing segments (3) of the first group are set or adjustable to a first radial position ( _r1 ) and wherein the bearing segments (3) of the first group have a first spring elasticity in the radial direction (r) and wherein the bearing segments (4) of the second group are set or adjustable to a second radial position ( _r2 ) that differs from the first radial position ( _r1 ), and wherein the bearing segments (4) the second group in radial direction (r) have a second spring elasticity which is different from the first spring elasticity, wherein the first radial position (r ₁ ) is larger than the second radial position (r ₂ ) and wherein the first spring elasticity is larger than the second spring elasticity. Main storage after Claim 1 , characterized in that the difference between the first radial position (r ₁ ) and the second radial position (r ₂ ) is between 0.1 mm and 5.0 mm. Main storage after Claim 1 or 2 , characterized in that the first spring elasticity is greater than the second spring elasticity by at least a factor of 3, preferably by at least a factor of 5. Main storage after one of the Claims 1 until 3 , characterized in that the bearing segments (3) of the first group and the bearing segments (4) of the second group are arranged axially (a) next to each other. Main storage after one of the Claims 1 until 3 , characterized in that the bearing segments (3) of the first group and the bearing segments (4) of the second group alternate in circumferential direction (U). Main storage after one of the Claims 1 until 5 , characterized in that at least the bearing segments (3, 4) of a group each consist of a support element (7, 8) which is arranged on a component (9, 10) made of elastomer material, wherein the component (9, 10) made of elastomer material is fixed to a housing part (11). Main storage after one of the Claims 1 until 6 , characterized in that the bearing segments (3) of the first group are provided with a fluid inflow to the bearing surface (5) in order to establish a hydrostatic bearing function. Main storage after one of the Claims 1 until 7 , characterized in that the bearing segments (3) of the first group are provided with adjusting means (12) with which the first radial position (r ₁ ) can be changed. Main storage after Claim 8 , characterized in that the adjusting means comprise a hydraulic piston-cylinder system which is used for adjusting the first radial position (r ₁ ). Main storage after Claim 8 , characterized in that the adjusting means have a mechanical adjusting system, in particular comprising a cup tappet, which is used for adjusting the first radial position (r ₁ ).