A method, device and system for detecting microwear of a pitch bearing

Abstract

The application provides a variable pitch bearing fretting wear detection method, device and system, the method comprises: by applying load at at least one target loading point on the target blade, so that the bending moment of the target blade reaches the preset bending moment; calculate the contact stress in the target variable pitch bearing raceway corresponding to the target blade under the preset bending moment; according to the correlation between the contact cycle number of the target variable pitch bearing and the contact stress, the contact cycle number of the target variable pitch bearing test is determined; control the target variable pitch bearing to run in the range of the rated one-way variable pitch angle for the contact cycle number to obtain the fretting wear detection result of the target variable pitch bearing. The application increases the bending moment by applying load, and then increases the contact stress to achieve the purpose of reducing the contact cycle number, which can realize the rapid verification of fretting wear, speed up the evaluation efficiency of the reliability of the variable pitch bearing, and improve the fretting wear detection precision to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of automated testing technology, and in particular to a method, apparatus and system for detecting fretting wear of pitch bearings. Background Technology

[0002] Pitch bearings connect the blades and hub of a wind turbine. Their operation allows the blades to be in the optimal windward position, enabling the turbine to operate safely, stably, and efficiently. Therefore, the reliability of pitch bearings is particularly important for wind turbines.

[0003] Fretting wear refers to a complex type of wear caused by small-amplitude vibrations between mutually pressed metal surfaces. Fretting wear often occurs before fatigue spalling, and in severe cases, it can even lead to bearing fracture failure, thus restricting the reliability and service life of pitch bearings.

[0004] Existing fretting wear testing devices are still in the experimental simulation stage. They generally use motor drive to simulate the wear state of the bearing within the pitch angle. That is, existing fretting wear testing devices test the wear degree of the pitch bearing through simulation, which differs greatly from the wear of the pitch bearing under the actual operation of the wind turbine. This results in defects in testing accuracy and testing efficiency. Summary of the Invention

[0005] This invention provides a method, apparatus, and system for detecting fretting wear in pitch bearings, which addresses the shortcomings of low accuracy and efficiency in existing fretting wear testing, achieves controllable contact stress, and improves the efficiency and accuracy of fretting wear detection in pitch bearings.

[0006] In a first aspect, the present invention provides a method for detecting fretting wear of a pitch bearing, comprising: applying a load at at least one target loading point on a target blade to make the bending moment of the target blade reach a preset bending moment; calculating the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment; determining the number of contact cycles for the target pitch bearing test based on the correlation between the number of contact cycles of the target pitch bearing and the contact stress; and controlling the target pitch bearing to cycle through the number of contact cycles within a rated unidirectional pitch angle range to obtain the fretting wear detection result of the target pitch bearing.

[0007] According to the method for detecting fretting wear of a pitch bearing provided by the present invention, the correlation between the number of contact cycles and the contact stress of the target pitch bearing is determined based on the following: the equivalent load of the target pitch bearing is determined according to the number of rollers and the rolling load of each roller; the correlation between the number of rotational fatigue cycles and the contact stress in the raceway of the target pitch bearing is determined according to the correlation between the rated dynamic load, the equivalent load and the number of rotational fatigue cycles of the target pitch bearing; and the correlation between the number of contact cycles and the contact stress of the target pitch bearing is determined by combining the correlation between the number of rotational fatigue cycles and the number of contact cycles.

[0008] According to the present invention, the ratio between the number of rotational fatigue revolutions and the number of contact cycles of the target pitch bearing is a constant.

[0009] According to the method for detecting fretting wear of a pitch bearing provided by the present invention, the rolling load of each roller is determined based on the following method: obtaining the contact line length, contact stress in the raceway, and the sum of the contact curvature of the contact surface between the roller and the raceway for each roller, so as to determine the rolling load of the roller.

[0010] According to the method for detecting fretting wear of a pitch bearing provided by the present invention, the sum of the contact curvatures of the contact surfaces of the roller and the raceway is determined based on the length of the short semi-shaft of the contact surfaces.

[0011] According to the present invention, a method for detecting fretting wear of a pitch bearing is provided, wherein the rated unidirectional pitch angle range is determined based on the following method: obtaining the unidirectional micro-amplitude pitch angle of the wind turbine during full-load operation; determining the weighted average of all collected unidirectional micro-amplitude pitch angles as the center value of the unidirectional pitch angle of the wind turbine; and determining the rated unidirectional pitch angle range based on the center value of the unidirectional pitch angle.

[0012] According to the present invention, a method for detecting fretting wear of a pitch bearing is provided, wherein the number of target loading points is multiple; the step of applying a load at at least one target loading point on a target blade to make the bending moment of the target blade reach a preset bending moment includes: applying a load at each target loading point so that the sum of the torques at all target points and the initial bending moment of the target blade is equal to the preset bending moment.

[0013] Secondly, the present invention also provides a pitch bearing fretting wear detection device, comprising: a load application unit for applying a load at at least one target loading point on a target blade to make the bending moment of the target blade reach a preset bending moment; a stress simulation unit for calculating the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment; a cycle calculation unit for determining the number of contact cycles of the target pitch bearing test based on the correlation between the number of contact cycles of the target pitch bearing and the contact stress; and a detection control unit for controlling the target pitch bearing to cyclically run the number of contact cycles within the rated unidirectional pitch angle range to obtain the fretting wear detection results of the target pitch bearing.

[0014] Thirdly, the present invention also provides a pitch bearing fretting wear detection system, comprising a target pitch bearing, a reducer, a motor encoder, a load application device, a force transmitter, and a processor; the reducer is used to drive the target pitch bearing to achieve unidirectional pitch control; the motor encoder is used to acquire the unidirectional pitch angle of the target pitch bearing; the load application device is used to apply a load at at least one target loading point on the target blade; the force transmitter is used to acquire the load value when the load application device applies the load; and the processor is used to execute the pitch bearing fretting wear detection method as described above.

[0015] According to the present invention, a pitch bearing fretting wear detection system is provided, wherein there are two target pitch bearings connected by an adapter flange; wherein the adapter flange is connected to the outer ring of one target pitch bearing and the inner ring of the other target pitch bearing respectively; one target pitch bearing is connected to the blade, and the other target pitch bearing is connected to the drive end of the engine unit.

[0016] Fourthly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the pitch bearing fretting wear detection methods described above.

[0017] Fifthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the pitch bearing fretting wear detection method as described above.

[0018] The pitch bearing fretting wear detection method, device, and system provided by this invention apply a load to increase the bending moment, thereby increasing the contact stress and reducing the number of contact cycles. This enables rapid verification of fretting wear, accelerates the evaluation efficiency of pitch bearing reliability, and improves the accuracy of fretting wear detection to a certain extent. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a fretting wear testing device provided by existing technology;

[0021] Figure 2 This is a schematic flowchart of the pitch bearing fretting wear detection method provided by the present invention;

[0022] Figure 3 This is a schematic diagram of applying a load to a target blade provided by the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of the pitch bearing fretting wear detection device provided by the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of the pitch bearing fretting wear detection system provided by the present invention;

[0025] Figure 6 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] It should be noted that in the description of the embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The terms "upper," "lower," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] Figure 1 This is a schematic diagram of the structure of a fretting wear testing device provided by existing technology, such as... Figure 1 As shown, it mainly includes load 1, swing arm 2, crank 3, motor 4, base 5, bracket 6, load bearing 7, bearing seat 8, experimental bearing 9, loading bearing 10 and loading rod 11.

[0029] The working principle of this fretting wear testing device is as follows: a load bearing 7 and a test bearing 9 are installed on the upper part of the bearing housing 8, and the load bearing 7 and the test bearing 9 are concentric; the base 5 is placed on the bracket 6, and the motor 4 is installed on the base 5, which drives the crank 3 to make a full circle motion. The crank 3 drives the pendulum 2 to swing back and forth. The swing angle of the test bearing 9 can be changed by changing the eccentricity of the pendulum 2; the axial load of the test bearing 9 is obtained by the loading bearing 10 through the upper loading rod 11. Changing the load 1 can make the test bearing 9 receive different loads.

[0030] The information recorded in this fretting wear testing device reveals that it simulates wind turbine operation by using an experimental bearing to mimic the working conditions of a pitch bearing. A motor drives a crank and a pendulum to pull the experimental bearing, subjecting it to fretting wear. Therefore, the device transfers load to a loading rod, which in turn, a loading bearing connected to the loading rod transfers the load to the experimental bearing. However, this existing device has several drawbacks. First, it simulates the fretting wear of a bearing, which differs significantly from the actual operating conditions of a wind turbine. Second, while the loading method reduces the testing cycle to some extent, it cannot accurately estimate the number of bearing contact cycles, leading to inaccurate test results and a lack of precision.

[0031] The following is combined with Figures 2 to 5 This invention describes the method, apparatus, and system for detecting fretting wear of pitch bearings provided in embodiments of the present invention.

[0032] Figure 2 This is a schematic flowchart of the pitch bearing fretting wear detection method provided by the present invention, as shown below. Figure 2 As shown, including but not limited to the following steps:

[0033] Step 101: Apply a load at at least one target loading point on the target blade so that the bending moment of the target blade reaches a preset bending moment;

[0034] Specifically, the target blade is the test blade that is directly connected to the target pitch bearing. By applying a load at at least one target loading point on the target blade, the bending moment of the target blade is increased, and finally the total bending moment of the target blade reaches the preset bending moment.

[0035] There can be one or more target loading points. The specific value of the load applied at the target loading point is not limited, as long as the total bending moment of the target blade reaches the preset bending moment after applying loads at all target loading points.

[0036] The preset bending moment is set in advance according to the practical needs of the specific scenario at the start of the fretting wear detection test.

[0037] Step 102: Calculate the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment;

[0038] Specifically, when the total bending moment of the target blade reaches the preset bending moment, the contact stress in the raceway of the target pitch bearing connected to the target blade is calculated. The pitch bearing raceway is the plane inside the bearing where the rollers roll. When the rollers roll on the pitch bearing raceway, the rollers and the raceway squeeze each other, generating stress. The contact stress is the maximum value of the total contact stress that the raceway can withstand.

[0039] There is a positive correlation between the bending moment of the target blade and the contact stress in the raceway of the target pitch bearing. When the bending moment of the target blade increases to the preset bending moment, the contact stress will also increase accordingly.

[0040] Step 103: Determine the number of contact cycles for the target pitch bearing test based on the correlation between the number of contact cycles and the contact stress.

[0041] Furthermore, after calculating the contact stress, the number of contact cycles for the target pitch bearing test can be determined based on the correlation between the contact stress and the number of contact cycles of the target pitch bearing. The number of contact cycles for the target pitch bearing test refers to the number of times the rollers circulate within the raceway.

[0042] Furthermore, the correlation between the number of contact cycles of the target pitch bearing and the contact stress refers to the correlation between the two under normal operating conditions of the wind turbine.

[0043] Assuming the product of the contact stress within the raceway of the target pitch bearing and the number of contact cycles of the target pitch bearing is a constant, an increase in contact stress will correspondingly decrease the number of contact cycles. Therefore, increasing the contact stress can effectively reduce the number of contact cycles, shorten the fretting wear detection test time, and achieve rapid verification of fretting wear.

[0044] As an optional embodiment, steps 101 to 103 of the above-described pitch bearing fretting wear detection method can all be completed by Bladed software pitch bearing timing simulation.

[0045] Bladed software is a wind turbine design software that can be used for load calculation and performance simulation. Therefore, using Bladed software to complete load calculation and determine contact stress and contact cycle number can not only restore the operating state of the target pitch bearing under fretting wear conditions more quickly and effortlessly, but also avoid the error risks that may occur due to manual operation, and more accurately determine the magnitude of applied load, preset bending moment, contact stress and contact cycle number.

[0046] Step 104: Control the target pitch bearing to run the contact cycle a certain number of times within the rated unidirectional pitch angle range to obtain the fretting wear detection results of the target pitch bearing.

[0047] The rated unidirectional pitch angle range refers to the range of pitch bearing angle changes when the pitch bearing experiences small-amplitude vibration. Controlling the target pitch bearing to operate within the rated unidirectional pitch angle range ensures that the target pitch bearing's current operating condition is equivalent to an operating condition prone to fretting wear.

[0048] Furthermore, ensure that the target pitch bearing operates within the rated unidirectional pitch angle range. After controlling the target pitch bearing to reach the aforementioned contact cycle count, obtain the result of whether the target pitch bearing fails due to the fretting wear failure mechanism, and use this result as the fretting wear detection result. If the target pitch bearing does not exhibit unreliable operation or reduced service life due to fretting wear, it can be considered that the target pitch bearing has passed the fretting wear failure mechanism test.

[0049] Based on the above analysis, using Figure 1 The existing fretting wear testing device provided in this paper determines the fretting wear detection result based on the number of cycles the experimental bearing undergoes when bearing failure occurs.

[0050] However, the pitch bearing fretting wear detection method provided by this invention determines the contact stress in the raceway of the target pitch bearing based on a pre-designed bending moment (i.e., preset bending moment), and then pre-determines a number of rotation cycles (i.e., contact cycle number) that is much smaller than the number of cycles required for fretting wear detection under normal operating conditions. Since the number of contact cycles is determined by this invention, the fretting wear detection result can be directly determined based on the state of the target pitch bearing after it has reached this number of cycles.

[0051] Therefore, it can be clearly compared that the pitch bearing fretting wear detection method provided by the present invention can effectively reduce the detection cycle of fretting wear detection and improve the efficiency of fretting wear detection compared with the detection method of the prior art which does not limit the number of cycles.

[0052] Meanwhile, the experimental object of the fretting wear testing method provided by this invention is the target pitch bearing, which is substantially different from the experimental object of the fretting wear testing device in the prior art, which is the experimental bearing. The fretting wear testing method provided by this invention implements the detection process of fretting wear of the pitch bearing in the actual working environment, while the fretting wear testing device in the prior art uses the data results of the number of cycles required for the experimental bearing to undergo fretting wear in a simulated environment, and then uses this data result to predict the fretting wear of the actual pitch bearing.

[0053] Therefore, the fretting wear test method provided by the present invention can accurately detect whether the target pitch bearing will fail due to fretting wear in the actual working environment, thereby leading to low reliability or reduced service life of the pitch bearing.

[0054] The pitch bearing fretting wear detection method provided by the present invention increases the bending moment by applying a load, thereby increasing the contact stress and reducing the number of contact cycles. This effectively accelerates the fretting wear detection efficiency and improves the fretting wear detection accuracy.

[0055] Based on the above embodiments, as an optional embodiment, the correlation between the number of contact cycles of the target pitch bearing and the contact stress involved in step 103 above is determined in the following way:

[0056] The equivalent load of the target pitch bearing is determined based on the number of rollers in the target pitch bearing and the rolling load of each roller.

[0057] Based on the correlation between the rated dynamic load, equivalent load, and number of rotational fatigue cycles of the target pitch bearing, the correlation between the number of rotational fatigue cycles of the target pitch bearing and the contact stress in the raceway is determined.

[0058] By combining the correlation between the number of rotational fatigue revolutions and the number of contact cycles of the target pitch bearing, the correlation between the number of contact cycles and the contact stress of the target pitch bearing is determined.

[0059] Specifically, the number of rollers in the target pitch bearing is the total number of rollers in the raceway of the target pitch bearing; the rolling load of each roller refers to the load applied to the raceway when each roller rolls in the raceway of the target pitch bearing; the equivalent load of the target pitch bearing is the theoretical calculated load of the target pitch bearing. During the simulation calculation, the target pitch bearing is regarded as bearing the actual load under the action of the theoretical calculated load.

[0060] Furthermore, based on the number of rollers in the target pitch bearing and the rolling load of each roller, the equivalent load generated during rolling in the raceway of the target pitch bearing can be determined, specifically by the following formula (1):

[0061] P = Q * Z (1)

[0062] Where Z is the number of rollers in the target pitch bearing; Q is the rolling load generated by each roller rolling in the raceway of the target pitch bearing; and P is the equivalent load generated by all rollers rolling in the raceway of the target pitch bearing.

[0063] Further, after determining the equivalent load of the target pitch bearing, the correlation between the rotational fatigue cycle number of the target pitch bearing and the contact stress in the raceway is determined based on the correlation between the rated dynamic load, equivalent load, and rotational fatigue cycle number of the target pitch bearing. The rotational fatigue cycle number of the target pitch bearing refers to the critical life at which fatigue wear will occur when the target pitch bearing reaches its rotational fatigue cycle number; the rated dynamic load of the target pitch bearing refers to the load that the pitch bearing can withstand when its basic rated life is exactly 1 million revolutions. Furthermore, the correlation between the rated dynamic load, equivalent load, and rotational fatigue cycle number of the target pitch bearing can be determined by the following formula (2):

[0064]

[0065] Wherein, L is the number of rotational fatigue revolutions of the target pitch bearing; C is the rated dynamic load of the target pitch bearing; and P is the equivalent load of the target pitch bearing.

[0066] Combining formula (2), the relationship between the number of rotational fatigue revolutions of the target pitch bearing and the contact stress in the raceway can be determined by the following formula (3):

[0067]

[0068] Wherein, L is the number of rotational fatigue revolutions of the target pitch bearing; C is the rated dynamic load of the target pitch bearing; S is the contact stress in the raceway of the target pitch bearing; le is the contact line length of the roller, which refers to the curve length of the contact between the roller and the raceway; ∑ρ is the sum of the contact curvatures of the contact surfaces of the roller and the raceway, which refers to the sum of the curvatures of the contact surfaces of the roller and the raceway; and Z is the number of rollers in the target pitch bearing.

[0069] The rotational fatigue revolutions and the number of contact cycles of the target pitch bearing satisfy a certain quantitative relationship. For example:

[0070] N = 100 * L

[0071] Where N is the number of contact cycles of the target pitch bearing, and L is the number of rotational fatigue revolutions of the target pitch bearing.

[0072] Combining the equal relationship between the number of rotational fatigue cycles and the number of contact cycles, the correlation between the number of contact cycles and the contact stress can be obtained by substituting it into formula (3).

[0073] Based on the above embodiments, as an optional embodiment, the ratio between the number of rotational fatigue revolutions and the number of contact cycles of the target pitch bearing is a constant.

[0074] Specifically, the above formula (3) can be further simplified to the following formula (4):

[0075]

[0076] Where L is the number of rotational fatigue revolutions of the target pitch bearing; S is the contact stress in the raceway of the target pitch bearing; and C′ is a constant.

[0077] In other words, there is always a constant relationship between the number of rotational fatigue cycles of the target pitch bearing and the contact stress in the raceway of the target pitch bearing. Combined with the fact that the number of rotational fatigue cycles of the target pitch bearing and the number of contact cycles satisfy a certain quantitative relationship, the relationship between the number of contact cycles and the contact stress in the raceway can be determined by the following formula (5):

[0078]

[0079] Where N is the number of contact cycles of the target pitch bearing; S is the contact stress in the raceway of the target pitch bearing; and C″ is a constant.

[0080] Furthermore, from formulas (4) and (5), the ratio between the number of rotational fatigue revolutions and the number of contact cycles of the target pitch bearing can be obtained as the ratio between two constants, C′ and C″.

[0081] The pitch bearing fretting wear detection method provided by the present invention increases the bending moment by applying a load, thereby increasing the contact stress and reducing the number of contact cycles. This effectively accelerates the fretting wear detection efficiency and improves the fretting wear detection accuracy.

[0082] Based on the above embodiments, as an optional embodiment, the rolling load of each roller is determined in the following manner:

[0083] The rolling load of each roller is determined by obtaining the contact line length of each roller, the contact stress within the raceway, and the sum of the contact curvatures of the contact surfaces where the roller contacts the raceway.

[0084] Specifically, after obtaining the contact line length of each roller, the contact stress in the raceway, and the sum of the contact curvatures of the contact surfaces where the roller and the raceway contact, the rolling load of the roller can be determined by the following formulas (6), (7), (8), and (9):

[0085]

[0086] Where Q is the rolling load of each roller; S is the contact stress in the raceway of the target pitch bearing; b is the length of the short half-shaft of the contact surface; and le is the contact line length of the roller.

[0087] As an optional embodiment, the sum of the contact curvatures of the contact surfaces of the roller and the raceway is determined based on the length of the minor semi-axis of the contact surfaces.

[0088] The minor axis length of the contact surface refers to the length of the minor axis length of the contact surface when the roller rolls in the raceway. The contact surface that contacts the raceway is an ellipse.

[0089] Furthermore, after obtaining the length of the minor semi-axis of the contact surface, the sum of the contact curvatures of the contact surfaces where the roller and the raceway contact each other can be determined by the following formula (7):

[0090]

[0091] Where b is the length of the minor axis of the contact surface; Q is the rolling load of each roller; le is the contact line length of the roller; and ∑ρ is the sum of the contact curvatures of the contact surfaces where the roller and the raceway come into contact.

[0092] From the above formulas (6) and (7), we can further obtain the following formula (8):

[0093]

[0094] Where Q is the rolling load of each roller; S is the contact stress in the raceway; le is the contact line length of the roller; and ∑ρ is the sum of the contact curvatures of the contact surfaces of the roller and the raceway.

[0095] Furthermore, combining Q at both ends of equation (8) yields the following equation (9):

[0096]

[0097] Where Q is the rolling load of each roller; S is the contact stress in the raceway; le is the contact line length of the roller; and ∑ρ is the sum of the contact curvatures of the contact surfaces of the roller and the raceway.

[0098] Finally, to more clearly illustrate the correlation between determining the number of contact cycles of the target pitch bearing and the contact stress provided by the embodiments of the present invention, the following embodiments are provided for illustration:

[0099] 1. Substitute formula (7) into formula (6) to obtain formula (8);

[0100] 2. By combining the Qs at both ends of formula (8), we can obtain formula (9). Combining formula (9), formula (1), and formula (2), we can obtain formula (3).

[0101] 3. Formula (3) can be further simplified into formula (4), and combined with the fact that the number of rotational fatigue revolutions of the target pitch bearing and the number of contact cycles satisfy a certain equal relationship, formula (5) is obtained from formula (4).

[0102] Based on the above embodiments, as an optional embodiment, the rated unidirectional pitch angle range involved in step 104 above is determined in the following way:

[0103] Obtain the unidirectional micro-amplitude pitch angle of the wind turbine during full-load operation.

[0104] The weighted average of all collected unidirectional micro-pitch angles is determined as the center value of the unidirectional pitch angle of the wind turbine.

[0105] The rated unidirectional pitch angle range is determined based on the center value of the unidirectional pitch angle.

[0106] Specifically, the pitch angle of each timing pitch bearing is obtained when the wind turbine operates under all load conditions. Then, based on the critical pitch angle value θ of the wind turbine... crit From the obtained pitch angles of each timing pitch bearing, select all pitch angles less than or equal to θ. crit The pitch angle is taken as the unidirectional micro-pitch angle. Wherein, θ crit It can be calculated using existing formulas.

[0107] Furthermore, based on the frequency of occurrence of each unidirectional micro-pitch angle, the weights of all obtained unidirectional micro-pitch angles are determined, and the average value of all weighted unidirectional micro-pitch angles is taken. This average value of the unidirectional micro-pitch angles is used as the center value of the unidirectional pitch angle of the wind turbine.

[0108] Furthermore, the rated unidirectional pitch angle range is determined based on the center value of the unidirectional pitch angle.

[0109] As an optional embodiment, it is assumed that a total of 100 pitch angles are obtained from the wind turbine's operation sequence under full load conditions; θ crit It is 2°; among all pitch angles, less than or equal to θ crit There are a total of 60, and these 60 are less than or equal to θ. crit The pitch angle is taken as the unidirectional micro-pitch angle. Assuming that there are 20 unidirectional micro-pitch angles of 0.5°, 20 unidirectional micro-pitch angles of 1°, and 20 unidirectional micro-pitch angles of 1.5°, the center value of the unidirectional pitch angle can be calculated by weighted average of these 60 unidirectional micro-pitch angles. The specific calculation can be obtained by the following formula (10):

[0110]

[0111] Where θ is the center value of the unidirectional pitch angle.

[0112] Therefore, based on the calculated center value θ of the unidirectional pitch angle, the rated unidirectional pitch angle range is determined to be the interval [0°, 1°].

[0113] The pitch bearing fretting wear detection method provided by this invention, based on weighted determination of the center value of the unidirectional pitch angle, can more accurately locate the actual pitch angle when fretting wear occurs in the pitch bearing, and more accurately detect the working condition of the target pitch bearing under fretting wear conditions.

[0114] Based on the above embodiments, as an optional embodiment, the number of target loading points involved in step 101 above is multiple;

[0115] The step of applying a load at at least one target loading point on the target blade to make the bending moment of the target blade reach a preset bending moment includes:

[0116] A load is applied at each of the target loading points such that the sum of the torques at all target points and the initial bending moment of the target blade is equal to the preset bending moment.

[0117] As a preferred embodiment, Figure 3 This is a schematic diagram of a specific embodiment of applying a load to a target blade provided by the present invention, as shown below. Figure 3 As shown, there are four target loading points on the target blade that are directly connected to the target pitch bearing. The same load or different loads can be applied to these four target loading points. It is only necessary to ensure that the torque provided at these four target loading points after the load is applied can make the total bending moment of the target blade reach the preset bending moment.

[0118] Furthermore, the total bending moment of the target blade can be obtained by the following formula:

[0119] M0 = F0 * L0

[0120] M=F1*L1+F2*L2+F3*L3+F4*L4+M0

[0121] Where M0 is the initial bending moment of the target blade; F0 is the weight of the target blade; L0 is the distance from the center of gravity of the target blade to the pitch bearing; M is the total bending moment of the target blade; F1 is the load applied at target loading point 1; L1 is the distance from target loading point 1 to the pitch bearing; F2 is the load applied at target loading point 2; L2 is the distance from target loading point 2 to the pitch bearing; F3 is the load applied at target loading point 3; L3 is the distance from target loading point 3 to the pitch bearing; F4 is the load applied at target loading point 4; L4 is the distance from target loading point 4 to the pitch bearing.

[0122] The pitch bearing fretting wear detection method provided by the present invention applies loads at multiple target loading points, which can ensure that the total bending moment of the target blade reaches the preset bending moment while ensuring that the target blade will not be affected by excessive load applied to only one target loading point, thus ensuring the operational reliability and service life of the target blade.

[0123] Figure 4 This is a schematic diagram of the structure of the pitch bearing fretting wear detection device provided by the present invention, as shown below. Figure 4 As shown, it mainly includes a load application unit 41, a stress simulation unit 42, a cycle calculation unit 43, and a detection and control unit 44, wherein:

[0124] The load application unit 41 is used to apply a load at at least one target loading point on the target blade so that the bending moment of the target blade reaches a preset bending moment.

[0125] The stress simulation unit 42 is used to calculate the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment.

[0126] The number of contact cycles calculation unit 43 is used to determine the number of contact cycles of the target pitch bearing test based on the correlation between the number of contact cycles of the target pitch bearing and the contact stress.

[0127] The detection control unit 44 is used to control the target pitch bearing to cyclically run the contact cycle number within the rated unidirectional pitch angle range in order to obtain the fretting wear detection result of the target pitch bearing.

[0128] It should be noted that the pitch bearing fretting wear detection device provided in this embodiment of the invention can execute the pitch bearing fretting wear detection method described in any of the above embodiments during specific operation, and this embodiment will not elaborate on this.

[0129] The pitch bearing fretting wear detection device provided by the present invention increases the bending moment by applying a load, thereby increasing the contact stress and reducing the number of contact cycles. This effectively accelerates the fretting wear detection efficiency and improves the fretting wear detection accuracy.

[0130] Figure 5 This is a schematic diagram of the structure of the pitch bearing fretting wear detection system provided by the present invention, as shown below. Figure 5 As shown, it mainly includes a target pitch bearing 51, a reducer 52, a motor encoder 53, a load application device 54, a force transmitter 55, and a processor 56, wherein:

[0131] The speed reducer 52 is used to drive the target pitch bearing 51 to achieve unidirectional pitch control;

[0132] The motor encoder 53 is used to obtain the unidirectional pitch angle of the target pitch bearing 51.

[0133] The load application device 54 is used to apply a load at at least one target loading point on the target blade;

[0134] The force transmitter 55 is used to obtain the load value when the load application device 54 applies a load.

[0135] The processor 56 is used to execute the pitch bearing fretting wear detection method described in any of the above embodiments.

[0136] The pitch bearing fretting wear detection system provided by this invention increases the bending moment by applying a load, thereby increasing the contact stress and reducing the number of contact cycles. This effectively accelerates the fretting wear detection efficiency and improves the fretting wear detection accuracy.

[0137] Based on the above embodiments, as an optional embodiment, there are two target pitch bearings, and the two target pitch bearings are connected by an adapter flange.

[0138] The adapter flange is connected to the outer ring of one target pitch bearing and the inner ring of another target pitch bearing.

[0139] One target pitch bearing is connected to the blade, and the other target pitch bearing is connected to the drive end of the engine unit.

[0140] Specifically, the two target pitch bearings are connected via an adapter flange, which is a component used for connecting shafts to each other. Connecting the blades via one target pitch bearing and the engine drive end via the other, and connecting the outer ring of one target pitch bearing to the inner ring of the other via the adapter flange, allows the inner ring of one target pitch bearing to rotate while the outer ring is fixed, and the inner ring of the other target pitch bearing to be fixed while the outer ring rotates. Both target pitch bearings can achieve axial rolling between the rollers and raceways, thus enabling small-amplitude vibrations under fretting wear conditions.

[0141] In addition, connecting the two target pitch bearings via an adapter flange can prevent jamming during continuous operation.

[0142] The pitch bearing fretting wear detection system provided by this invention can more accurately verify the operational reliability of the target pitch bearing by conducting fretting wear detection tests on two target pitch bearings under different rotation conditions, ensuring that the working life of the target pitch bearing will not have a large error.

[0143] Figure 6 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 6 As shown, the electronic device may include a processor 610, a communication interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other via the communication bus 640. The processor 610 can call logical instructions in the memory 630 to execute a pitch bearing fretting wear detection method. This method includes: applying a load at at least one target loading point on a target blade to make the bending moment of the target blade reach a preset bending moment; calculating the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment; determining the number of contact cycles for the target pitch bearing test based on the correlation between the number of contact cycles and the contact stress; and controlling the target pitch bearing to cycle through the number of contact cycles within the rated unidirectional pitch angle range to obtain the fretting wear detection results of the target pitch bearing.

[0144] Furthermore, the logical instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0145] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer is able to execute the pitch bearing fretting wear detection method provided in the above embodiments, the method comprising: applying a load at at least one target loading point on a target blade to make the bending moment of the target blade reach a preset bending moment; calculating the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment; determining the number of contact cycles of the target pitch bearing test according to the correlation between the number of contact cycles of the target pitch bearing and the contact stress; controlling the target pitch bearing to cycle through the number of contact cycles within the rated unidirectional pitch angle range to obtain the fretting wear detection result of the target pitch bearing.

[0146] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the pitch bearing fretting wear detection method provided in the above embodiments. The method includes: applying a load at at least one target loading point on a target blade to make the bending moment of the target blade reach a preset bending moment; calculating the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment; determining the number of contact cycles for the target pitch bearing test based on the correlation between the number of contact cycles of the target pitch bearing and the contact stress; and controlling the target pitch bearing to cycle through the number of contact cycles within the rated unidirectional pitch angle range to obtain the fretting wear detection result of the target pitch bearing.

[0147] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0148] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting fretting wear in a pitch bearing, characterized in that, include: By applying a load at at least one target loading point on the target blade, the bending moment of the target blade reaches a preset bending moment; Calculate the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment; The number of contact cycles for the target pitch bearing test is determined based on the correlation between the number of contact cycles and the contact stress. The target pitch bearing is controlled to cyclically run the contact cycle number within the rated unidirectional pitch angle range to obtain the fretting wear detection results of the target pitch bearing; The correlation between the number of contact cycles of the target pitch bearing and the contact stress is determined based on the following method: The equivalent load of the target pitch bearing is determined based on the number of rollers in the target pitch bearing and the rolling load of each roller. Based on the correlation between the rated dynamic load, equivalent load, and number of rotational fatigue cycles of the target pitch bearing, the correlation between the number of rotational fatigue cycles of the target pitch bearing and the contact stress in the raceway is determined. By combining the correlation between the number of rotational fatigue revolutions and the number of contact cycles of the target pitch bearing, the correlation between the number of contact cycles and the contact stress of the target pitch bearing is determined.

2. The method for detecting fretting wear of pitch bearings according to claim 1, characterized in that, The ratio between the number of rotational fatigue revolutions and the number of contact cycles of the target pitch bearing is a constant.

3. The method for detecting fretting wear of pitch bearings according to claim 1, characterized in that, The rolling load on each roller is determined based on the following method: The rolling load of each roller is determined by obtaining the contact line length of each roller, the contact stress within the raceway, and the sum of the contact curvatures of the contact surfaces where the roller contacts the raceway.

4. The method for detecting fretting wear of pitch bearings according to claim 1, characterized in that, The sum of the contact curvatures of the contact surfaces where the roller contacts the raceway is determined based on the length of the minor semi-axis of the contact surfaces.

5. The method for detecting fretting wear of pitch bearings according to claim 1, characterized in that, The rated unidirectional pitch angle range is determined based on the following method: Obtain the unidirectional micro-amplitude pitch angle of the wind turbine during full-load operation. The weighted average of all collected unidirectional micro-pitch angles is determined as the center value of the unidirectional pitch angle of the wind turbine. The rated unidirectional pitch angle range is determined based on the center value of the unidirectional pitch angle.

6. The method for detecting fretting wear of pitch bearings according to claim 1, characterized in that, The number of target loading points is multiple; The step of applying a load at at least one target loading point on the target blade to make the bending moment of the target blade reach a preset bending moment includes: A load is applied at each of the target loading points such that the sum of the torques at all target points and the initial bending moment of the target blade is equal to the preset bending moment.

7. A device for detecting fretting wear of pitch bearings, characterized in that, include: A load application unit is used to apply a load at at least one target loading point on a target blade so that the bending moment of the target blade reaches a preset bending moment. The stress simulation unit is used to calculate the contact stress in the raceway of the target pitch bearing corresponding to the target blade under the preset bending moment. The cycle count unit is used to determine the number of contact cycles for the target pitch bearing test based on the correlation between the number of contact cycles and the contact stress; to determine the equivalent load of the target pitch bearing based on the number of rollers and the rolling load of each roller; to determine the correlation between the number of rotational fatigue cycles and the contact stress in the raceway based on the correlation between the rated dynamic load, equivalent load, and number of rotational fatigue cycles of the target pitch bearing; and to determine the correlation between the number of contact cycles and the contact stress by combining the correlation between the number of rotational fatigue cycles and the number of contact cycles. The detection and control unit is used to control the target pitch bearing to cyclically run the contact cycle number within the rated unidirectional pitch angle range to obtain the fretting wear detection results of the target pitch bearing.

8. A fretting wear detection system for pitch bearings, characterized in that, Includes target pitch bearing, gearbox, motor encoder, load application device, force transmitter and processor; The speed reducer is used to drive the target pitch bearing to achieve unidirectional pitch control; The motor encoder is used to obtain the unidirectional pitch angle of the target pitch bearing; The load application device is used to apply a load at at least one target loading point on the target blade; The force transmitter is used to acquire the load value when the load applying device applies a load. The processor is used to execute the pitch bearing fretting wear detection method as described in any one of claims 1-6.

9. The pitch bearing fretting wear detection system according to claim 8, characterized in that, There are two target pitch bearings, and the two target pitch bearings are connected by an adapter flange; The adapter flange is connected to the outer ring of one target pitch bearing and the inner ring of another target pitch bearing. One target pitch bearing is connected to the blade, and the other target pitch bearing is connected to the drive end of the engine unit.

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