Method for changing the load on a loaded component of a pitch bearing

Abstract

Method for changing the load of a loaded component of a pitch bearing, comprising the following steps: Determining a speed difference between an inner ring and a loaded component of the pitch bearing, wherein the inner ring serves to connect to a blade; and Rotating the inner ring and the loaded component relative to a certain angle according to the following formula such that the load on the loaded component changes and that the loaded component is no longer in a heavy load area, where the heavy load area is an area that is loaded with the maximum gravity of the blade and the loaded component includes a ball of the pitch bearing and a holder of the pitch bearing: nm = ni 2 ( 1 − γ ) , γ = D cos ∝ dm , where n m The rotational speed of the combination of the ball and the holder is, n iwhere is the rotational speed of the inner ring or blade, D is the diameter of the ball, α is a contact angle, and dm is the distribution circle diameter of a rolling body.

Description

TECHNICAL AREA

[0001] The invention generally relates to the field of wind power generation, and in particular to a method for changing the load on a loaded component of a pitch bearing. Furthermore, the invention relates to a system for changing the load on a loaded component of a pitch bearing. STATE OF THE ART

[0002] In recent years, the clean energy sector has experienced rapid development as countries pay more attention to environmental concerns. As a new type of energy source, clean energy offers advantages over traditional fossil fuels, including widespread availability, renewability, and low pollution. The use of wind turbines is a particularly significant example of a clean energy source.

[0003] A key component of a wind turbine (or WTG) is the pitch bearing, which adjusts the angle between the turbine blade and the blade's plane of rotation. This creates a windward angle, thus increasing the turbine's power output. Generally, replacing the pitch bearing requires removing the blade, and after the replacement, the blade is lifted and reinstalled. Wind turbine blades are typically dozens of meters long, such as 30 meters, and weigh hundreds of kilograms. Replacing a pitch bearing involves relatively high costs and certain risks. Therefore, ways to extend the lifespan of the pitch bearing are a key industry concern.

[0004] German patent applications DE 10 2016 113 786 A1 and DE 10 2016 113 785 A1 each describe a method for adjusting the pitch angle of a rotor blade of a wind turbine and a corresponding wind turbine. US patent 2011 / 0291422 A1 describes a wind turbine generator and a roller bearing for a wind turbine generator. REVELATION OF THE INVENTION

[0005] Therefore, an object of the present invention is to provide a method and a corresponding system for changing the load on a loaded component of a pitch bearing. The method and / or system can significantly reduce the probability that one and the same loaded component of a pitch bearing is always in a heavy-load range, thereby greatly increasing the service life of the pitch bearing.

[0006] According to a first aspect of the present application, the problem is solved by a method for changing a load on a loaded component of a pitch bearing according to claim 1, which includes, among other things, the following steps: Determining a speed difference between an inner ring and a loaded component of the pitch bearing, wherein the inner ring serves to connect to a blade; and Rotating the inner ring relative to the loaded component by a certain angle such that the load on the loaded component changes.

[0007] It should be noted that the phrase "rotational speed difference between an inner ring and a loaded component of the pitch bearing" refers to a difference between the rotational speed of the inner ring of the pitch bearing around a rotating shaft of the pitch bearing and the rotational speed of the loaded component around the rotating shaft of the pitch bearing. The rotational speed can, for example, include a linear velocity and an angular velocity. Furthermore, the inventor discovers that a speed difference between a loaded component, such as a ball and a holder, and the inner ring depends on the rotational speed of the inner ring. Therefore, a desired relative angle of rotation between the loaded component and the inner ring can be achieved after the inner ring has rotated through a specific angle.Furthermore, it should be noted that the terms "inner ring" and "outer ring" in the present invention serve only for differentiation and do not define the relationship between two ring bodies with respect to their inner and outer arrangement; however, the inner ring is a rotatable ring body connected to blades, and the outer ring is a non-rotatable ring body attached to a hub. Therefore, in some embodiments, it is possible for an inner ring to be arranged outside of an outer ring or even inside an outer ring, but all these scenarios fall within the scope of the present invention.

[0008] In a preferred embodiment of the present invention, the loaded component comprises at least one of the following: a ball of the pitch bearing and a retainer of the pitch bearing. The ball and the retainer are components of the pitch bearing that are subjected to relatively high forces and are easily damaged. The service life of the pitch bearing can thus be significantly increased if such components are not constantly located in a high-load area. It should be noted that the loaded component according to the invention is not limited to a ball or a retainer, but that in other pitch bearing designs, further components can be included between the inner and outer rings of the pitch bearing, as well as respective loaded segments of the outer ring.

[0009] In a further development of the present invention, it is provided that determining the speed difference between the inner ring and the loaded component of the pitch bearing comprises: Calculating the rotational speed difference between the ball and / or the holder and the inner ring blade, depending on the pitch bearing's specification parameters. This improved method allows for easy determination of the rotational speed difference. Other approaches to determining the rotational speed are also conceivable, e.g.: performing a rotational speed measurement using a speed sensor; performing a pressure measurement using a pressure sensor to determine the angular position of a loaded component; determining the position of the loaded components using a proximity sensor to determine the rotational speed difference, etc.

[0010] In a further development of the present invention, it is provided that the rotation of the inner ring and the loaded component relative to each other by a certain angle, such that the load on the loaded component changes, comprises the following steps: Determine the most stressed component; and Rotating the inner ring and the most heavily loaded component relative to each other by a certain angle such that the most heavily loaded component is no longer the most heavily loaded component.

[0011] In a preferred embodiment of the present invention, the angle is between 120° and 140°. This preferred embodiment allows the loaded component to be effectively excluded from the heavy load range with a relatively small rotation angle.

[0012] In a further development of the present invention, it is provided that the rotation of the inner ring and the loaded component relative to each other by a certain angle such that the load on the loaded component changes comprises: the rotation of the inner ring and the loaded component relative to a certain angle such that the loaded component is no longer in a heavy load area, where the heavy load area is an area that is subjected to the maximum gravity of the blade.

[0013] In a further development of the present invention, it is provided that the process is carried out periodically.

[0014] In a second aspect of the present invention, the problem is solved by a system for changing the load of a loaded component of a pitch bearing according to claim 3, which includes, among other things: a controller designed to perform the following actions: Determining a speed difference between an inner ring and a loaded component of the pitch bearing, wherein the inner ring serves to connect to a blade; and Generating a control signal depending on the speed difference; an actuator designed to rotate the inner ring and the loaded component relative to each other by a certain angle depending on the control signal, such that the load on the loaded component changes.

[0015] The controller can be implemented, for example, by means of software, hardware, firmware or a combination thereof, while the actuator can be implemented, for example, by means of a motor located in the hub to rotate the blade, i.e. the inner ring can be rotated by rotating the blade.

[0016] In a preferred embodiment of the present invention, it is provided that the loaded component comprises at least one of the following: a ball of the pitch bearing and a holder of the pitch bearing.

[0017] Furthermore, the present invention relates to a wind turbine comprising the system according to the present invention.

[0018] The present invention has at least the following advantageous effects: Following a study, the inventor arrives at the following clear insight: The service life of the pitch bearing is primarily determined by its loaded component, such as a ball, a holder, and the like, while the pitch circumference of wind turbine blades is always between 0° and 90°. Consequently, the pitch bearing operates in a pivoting manner; therefore, some balls and holders are constantly operating in the heavy-load range, which reduces the service life of the pitch bearing. Simultaneously, the inventor discovers that the speed difference between a loaded component, such as a ball, a holder, and the like, and the inner ring depends on the rotational speed of the inner ring. Therefore, a desired relative angle of rotation between the loaded component and the inner ring can be achieved after the inner ring has rotated through a specific angle.The present invention thus enables a rotational speed difference between a combination of a ball and a holder of a pitch bearing and an inner ring, after the inner ring (the blade) has been rotated by a certain angle, to cause the combination of the ball and the holder to rotate relative to the inner ring (the blade) by a specific angle. By implementing this concept, for example at regular intervals, it is possible to ensure that a loaded component such as a ball, a holder, and the like is subjected to a uniform load during its service life, thereby effectively extending the service life of the pitch bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is described in more detail below in combination with specific embodiments with reference to the figures. Fig. Figure 1 shows a top view of a pitch bearing of a wind turbine; and Fig. Figures 2A to 2B illustrate the principle of the concepts according to the invention. FORMS OF EXECUTION OF THE INVENTION

[0020] It should be noted that the respective assemblies in the figures are exaggerated for illustrative purposes and are not necessarily to scale. Identical or functionally equivalent assemblies in the figures are marked with the same reference symbol.

[0021] Unless otherwise specified, in the present invention the phrases "is arranged on ...", "is arranged above ...", and "is arranged over ..." do not preclude the presence of an intermediate means. Furthermore, the phrase "is arranged on or above ..." merely refers to a relative positional relationship between two components; and in certain cases, such as after reversing a product direction, it can also be changed to "is arranged below or under ...", and vice versa.

[0022] In the present invention, the respective embodiments serve only to describe the concepts of the present invention and are not to be understood as limiting.

[0023] Unless otherwise stated, the counter words "a" and "an" do not exclude the scene of the presence of multiple elements.

[0024] It should be noted that, for the sake of clarity and simplicity, only a subset of components or assemblies are shown in the exemplary embodiments of the present invention. However, the person skilled in the art will understand that, by applying the teachings of this invention, components or assemblies required in a specific scenario can be added as needed.

[0025] It should be noted that, within the scope of the present invention, the terms "equal," "identical," "equivalent," or the like do not imply that the values ​​of the two are absolutely equal; rather, a certain degree of rational error is permitted. That is to say, these terms also include "essentially equal," "essentially identical," and "essentially equivalent." Similarly, the technical terms relating to directions, namely "perpendicular to," "parallel to," and the like, also include, in the present invention, the meanings of "essentially perpendicular to" and "essentially parallel to."

[0026] Furthermore, the numbering of the steps in the respective methods of the present invention does not restrict the order in which the method steps may be carried out. Unless otherwise specified, the respective method steps may be carried out in different sequences.

[0027] In the present invention, the controller can be implemented using software, hardware, firmware, or a combination thereof. The controller can be a separate component or an integral part of a larger component.

[0028] The present invention will be described in more detail below in combination with specific embodiments with reference to the figures.

[0029] Fig. Figure 1 shows a top view of a pitch bearing 100 of a wind turbine.

[0030] As in Fig. As shown in Figure 1, the pitch bearing 100 comprises an inner ring 101 and an outer ring 102. Blades (not shown) are connected to the inner ring 101 of the pitch bearing by bolts. The inner ring 101 and the outer ring 102 of the pitch bearing are connected via a four-point contact of the ball 103 and transmit charges. It should be noted that the terms "inner ring" and "outer ring" are used for differentiation only and do not define the relationship between two ring bodies with respect to their inner and outer arrangement. The inner ring is a rotatable ring body connected to blades, and the outer ring is a non-rotatable ring body attached to a hub. Therefore, in some embodiments, an inner ring may be arranged outside or inside an outer ring, but all these scenarios fall within the scope of the present invention.The inner ring 101 is connected to blades and is therefore rotatable for adjusting the blade angle of the blades, namely an enclosing angle between a wind turbine blade and a plane of rotation of the blade. From . Fig. 1. It is evident that, due to the presence of the relatively large gravitational force of the blade and the arrangement of the pitch bearing not in a horizontal direction (normally it is located on different planes with the rotation of the hub), some components of the pitch bearing (e.g., ball and holder for holding balls) are probably located in an area with large charges, while another component is probably located in an area with small charges.

[0031] Fig. Figures 2A to 2B illustrate the principle of the concepts according to the invention.

[0032] As in Fig. As shown in Figure 2A, the inventor, after conducting a study, arrives at the following clear insight: The service life of the pitch bearing is primarily determined by its loaded component, such as a ball 103, a holder 104, and the like, while the pitch circumference of wind turbine blades is always between 0° and 90°. Consequently, the pitch bearing operates in a pivoting manner; therefore, some balls 103 and holders 104 constantly operate in the heavy-load range, which reduces the service life of the pitch bearing. Simultaneously, the inventor discovers that the speed difference between a loaded component, such as a ball 103 and a holder 104, and the like, and the inner ring 101 depends on the rotational speed of the inner ring 101 (see the following description for details).Therefore, a desired relative angle of rotation between the loaded component – ​​the ball 103 and the holder 104 – and the inner ring 101 can be achieved after the inner ring 101 has rotated through a specific angle. Thus, the present invention, with a rotational speed difference of a combination of a ball 103 and a holder 104 of a pitch bearing and an inner ring 101, allows the combination of the ball 103 and the holder 104 to rotate relative to the inner ring (the blade) through a specific angle after the inner ring 101 (the blade) has been rotated through a certain angle, thereby changing the force distribution of the respective loaded components. By implementing this concept, for example at regular intervals, it is possible to ensure that a loaded component such as a ball 103, a holder 104, and the like is subjected to a uniform load throughout its service life, thereby effectively extending the service life of the pitch bearing.

[0033] It will be on Fig. 2B is referenced. The following relationship applies to the speed difference between the ball 103, the holder 104 and the inner ring 101, and the rotational speed of the inner ring 101: nm=ni2(1−γ); γ=D cos ∝dm, where n m The rotational speed of the combination of the ball 103 and the holder 104 is, n i where D is the rotational speed of the inner ring 101 or the blade, D is the diameter of the ball 103, α is a contact angle, and d m is the distribution circle diameter of a rolling body.

[0034] A study found that it is possible to effectively avoid the same balls always being in the heavy load area by rotating the combination of the holder 104 and the ball 103 by 140 to 106 degrees at regular intervals with respect to the inner ring 101 or the blade.

[0035] A 55.2430 pitch bearing is given as an example. The ball diameter is 55 mm, the roller track distribution circle diameter is 2430 mm, γ = 0.016, and the speed ratio is n. m and n i The ratio is 0.4920. When the inner ring (the blade) of the pitch bearing rotates a full 9 revolutions, the ball and holder combination rotates 4.43 revolutions, and the ball and holder rotate 154° relative to the inner ring (the blade). A service interval of every two years is given as an example. Over 20 years of operation, the time that the same part of the ball and holder is in the heavy-duty range will be reduced ninefold, thus significantly extending the service life of the pitch bearing.

[0036] Although some embodiments of the present invention are described in the present application documents, those skilled in the art will understand that these embodiments are presented only as examples. Based on the teaching of the invention, those skilled in the art can devise many variants, alternatives, and further developments without exceeding the scope of the present invention. The attached set of claims aims to limit the scope of the present invention and thus include the claims per se, as well as methods and structures to an equivalent extent.

Claims

[1] Method for changing the load of a loaded component of a pitch bearing, comprising the following steps: Determining a speed difference between an inner ring and a loaded component of the pitch bearing, wherein the inner ring serves to connect to a blade; and Rotating the inner ring and the loaded component relative to a certain angle according to the following formula such that the load on the loaded component changes and that the loaded component is no longer in a heavy load area, where the heavy load area is an area that is loaded with the maximum gravity of the blade and the loaded component includes a ball of the pitch bearing and a holder of the pitch bearing: nm=ni2(1−γ), γ=D cos ∝dm, where n m The rotational speed of the combination of the ball and the holder is, n iwhere is the rotational speed of the inner ring or blade, D is the diameter of the ball, α is a contact angle, and dm is the distribution circle diameter of a rolling body. [2] Method according to claim 1, wherein the method is carried out periodically. [3] System for changing the load of a loaded component of a pitch bearing, comprising: a controller designed to perform the following actions: Determining a speed difference between an inner ring and a loaded component of the pitch bearing, wherein the inner ring serves to connect to a blade; and Generating a control signal depending on the speed difference; an actuator designed to rotate the inner ring and the loaded component relative to the control signal by a certain angle according to the following formula, such that the load on the loaded component changes and the loaded component is no longer in a heavy load area, where the heavy load area is an area subjected to the maximum gravity of the blade and the loaded component comprises a ball of the pitch bearing and a holder of the pitch bearing: nm=ni2(1−γ), γ=D cos ∝dm, where n m The rotational speed of the combination of the ball and the holder is, n i where is the rotational speed of the inner ring or blade, D is the diameter of the ball, α is a contact angle, and dm is the distribution circle diameter of a rolling body. [4] Wind power plant comprising the system according to claim 3.

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