Wind power three-row cylindrical roller bearing oil groove stress calculation method

Abstract

The invention relates to the technical field of bearing design, in particular to a wind power three-row cylindrical roller bearing oil groove stress calculation method, which comprises the following steps of: 1, calculating load distribution and roller contact bandwidth of two rows of rollers of an axial raceway by using an analytical solution method or a numerical solution method according to stress and bearing parameters of a three-row cylindrical roller bearing; 2, establishing a ferrule three-dimensional model by utilizing three-dimensional software, and segmenting loading positions on a raceway one by one according to the calculated roller contact bandwidth; and 3, importing the three-dimensional model into finite element software, and setting material attributes, a fixed bottom surface and a mounting hole in the finite element software. Complex analysis problems are simplified, load distribution calculation, three-dimensional modeling, raceway segmentation, constraint and load application of the rollers are all controlled and executed by programs, the analysis speed is high, and the bearing design period is shortened.

Description

Technical Field

[0001] This invention relates to the field of bearing design technology, specifically a method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines. Background Technology

[0002] Three-row cylindrical roller bearings are crucial connecting components between the blades and hub in wind turbines. They bear radial forces, axial forces, and very large overturning moments. Due to the high stress, the probability of bearing failure is greatly increased. Moreover, the axial raceway of this type of bearing is equivalent to a cantilever beam structure, making the raceway root more susceptible to damage. Therefore, the design of the oil groove at the raceway root is extremely critical. Traditional oil groove calculations use a finite element method with a unified model of the blades, bearings, and hub. While this algorithm is accurate, it is time-consuming. If the design is not reasonable, repeated calculations are required, resulting in a long bearing design cycle that is difficult to keep up with the rapid development of the market. Therefore, we have found a simplified method without affecting the analysis results. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the present invention provides a method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind power, which simplifies the complex analysis problem. The calculation of the load distribution of the rollers, three-dimensional modeling, raceway division, constraints, and load application are all executed by program control, which is fast and shortens the bearing design cycle.

[0004] To achieve the above objectives, the technical solution provided by this invention is a method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines, including...

[0005] Step 1: Based on the forces and bearing parameters of the three-row cylindrical roller bearing, use analytical or numerical methods to calculate the load distribution and roller contact bandwidth of the two rows of rollers in the axial raceway.

[0006] Step 2: Use 3D software to create a 3D model of the raceway, and divide the loading position on the raceway one by one according to the calculated roller contact bandwidth.

[0007] Step 3: Import the 3D model into the finite element software, set the material properties, and fix the bottom surface and mounting holes in the finite element software;

[0008] Step 4: Divide the grid; the positions of the oil grooves and the loading positions cut out by the rollers need to be refined.

[0009] Step 5: Apply the calculated load for each roller to the pre-divided raceway position one by one, and then perform operational analysis;

[0010] Step 6: Check the results after the calculation is complete.

[0011] Furthermore, the analytical solution method described in step one:

[0012] in: This is the angle when the rolling element load is zero. PAmax1 and PAmax2 represent the axial components of the maximum rolling element load on the main thrust and auxiliary thrust raceways, respectively. According to the deformation compatibility condition, this is located at any angular position. Main thrust

[0013] Axial load on raceway rolling elements:

[0014]

[0015] The total axial force Fa1 on one side of the main thrust raceway is:

[0016]

[0017] Let the contact angle of the rolling element be α, then the maximum load P of the rolling element is... max1 =PA max1 / sinα;

[0018] Fa1 = P max1 ×sinα×Z×J0(ε1);

[0019] Similarly, the total axial force Fa2 on one side of the auxiliary thrust raceway is:

[0020] Fa2=P max2 ×sinα×Z×J0(ε2);

[0021] According to the static equilibrium condition:

[0022]

[0023] The resultant moment M1 on one side of the main thrust raceway is:

[0024]

[0025]

[0026] Similarly, the resultant moment M2 on one side of the auxiliary thrust raceway is:

[0027]

[0028] The resultant moment of M1 and M2 should be balanced with the applied overturning moment M.

[0029]

[0030] Dividing equation (1-1-2) by (1-1-3) yields:

[0031] Furthermore, the numerical solution method described in step one:

[0032] Assuming the outer ring remains stationary, when the inner ring of the bearing is simultaneously subjected to axial force Fa, radial force Fr, and overturning moment M, corresponding axial displacement δa, radial displacement δr, and rotation angle θ will be generated; let the angle... It is the angle between the rolling element with the greatest load and the other rolling elements; before the bearing is loaded, the distance between the centers of curvature of the inner and outer ring grooves is the same at any angular position, called the original groove center distance A, then A = (f i +f e -1)×Dw;

[0033] Four-point contact ball slewing bearings have two sets of raceways on both the inner and outer rings; the raceway that mainly bears the axial force is called the main thrust raceway, and the other raceway is called the auxiliary thrust raceway; when the bearing is loaded, the center distance between the main and auxiliary thrust raceways changes.

[0034] At any angle position At this point, the center-to-center distance of the main and auxiliary thrust raceways They were changed to:

[0035]

[0036] In the formula: α0 is the initial contact angle, The total elastic deformation of the steel ball and the main and auxiliary thrust raceways It equals the difference between the center-to-center distance of the groove after the inner ring displacement and the original center-to-center distance, i.e. According to Hertz contact theory, the load Q acting on the steel ball and the total elastic deformation δ between the steel ball and the inner and outer raceways are related as follows: Q = K n ×δ 1.5 ;K n Deformation constant;

[0037] The position of any angle can be determined from this formula. Load on the steel ball:

[0038] Load on the steel balls on the main thrust raceway

[0039] Load on steel balls on the auxiliary thrust raceway

[0040] After the inner ring is displaced, at different angular positions Contact angle of the steel ball at the point The contact angle of the main thrust raceway steel balls will also change. It becomes:

[0041]

[0042] Contact angle of the auxiliary thrust raceway steel ball It becomes:

[0043]

[0044] Establish the static equilibrium equations for the inner ring, which state that the forces exerted by all steel balls on the inner ring should be balanced by the external forces:

[0045] The above three equations form a three-dimensional nonlinear equation system with the inner ring displacement as the unknown quantity. When the external load is given, the numerical solution method of the equation system is used to obtain δa, δr, and θ. Then, the load distribution of the rolling element can be obtained by using equations (1-2-1) and (1-2-2).

[0046] Further, step one: Write a program according to the above method to calculate the load distribution of the axial rollers in the raceway; enter the main parameter input interface to input the bearing main parameters; enter the load input interface to input the load; export the FEA data after the calculation is completed.

[0047] Further, step two: Write an automatic calculation program to drive the three-dimensional finite element analysis software; after entering the main page, select the bearing type to be calculated; enter the bearing parameter input interface and input the bearing parameters as required; after the parameters are input, confirm the dimensions and generate the three-dimensional drawing.

[0048] Further, steps three through five: Enter the finite element interface and constrain the generated 3D model in the main program; automatically apply loads to the pre-divided raceways in the main program; after the constraints and loads are created, define the material properties of the model; finally, use the meshing tool provided by the software to divide the model into a mesh with hexahedral elements.

[0049] The beneficial effects of this invention are as follows: This analysis method first calculates the force on each rolling element based on the force of the slewing bearing using analytical or numerical methods. Then, the model of the slewing bearing ring to be analyzed is established in finite element software. Finally, the calculated force on each rolling element is applied to the corresponding position of the slewing bearing ring model for analysis and calculation to obtain the stress results. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the axial raceway roller load distribution.

[0051] Figure 2 The main program diagram for calculating the axial raceway roller load;

[0052] Figure 3 Diagram of the main parameter input interface for three-row cylindrical roller bearings;

[0053] Figure 4 Diagram of the input interface for external loads of three rows of cylindrical roller bearings;

[0054] Figure 5 A diagram showing the calculated axial roller load and contact half-width.

[0055] Figure 6 The main program diagram for automatically creating a 3D model;

[0056] Figure 7 To create a program diagram for a three-row cylindrical ring system;

[0057] Figure 8 Input diagram for parameters of three rows of cylindrical rings;

[0058] Figure 9 A model diagram of three rows of cylindrical rings;

[0059] Figure 10 For constrained mounting hole procedure diagram;

[0060] Figure 11 This is a diagram of the ring constraint model;

[0061] Figure 12 Program diagram for loading roller load;

[0062] Figure 13 A model diagram of the raceway after applying roller load;

[0063] Figure 14 A ring-shaped grid diagram;

[0064] Figure 15 The equivalent stress diagram of the oil groove of the ring is calculated;

[0065] Figure 16 This is a diagram showing the calculated safety factor for the oil groove of the ring. Detailed Implementation

[0066] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0067] like Figures 1-16 As shown, one embodiment of the present invention provides a method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines, including...

[0068] Step 1: Based on the forces and bearing parameters of the three-row cylindrical roller bearing, use analytical or numerical methods to calculate the load distribution and roller contact bandwidth of the two rows of rollers in the axial raceway.

[0069] Step 2: Use 3D software to create a 3D model of the raceway, and divide the loading position on the raceway one by one according to the calculated roller contact bandwidth.

[0070] Step 3: Import the 3D model into the finite element software, set the material properties, and fix the bottom surface and mounting holes in the finite element software;

[0071] Step 4: Divide the grid; the positions of the oil grooves and the loading positions cut out by the rollers need to be refined.

[0072] Step 5: Apply the calculated load for each roller to the pre-divided raceway position one by one, and then perform operational analysis;

[0073] Step 6: Check the results after the calculation is complete.

[0074] In one embodiment, step one is an analytical solution method:

[0075] in: This is the angle when the rolling element load is zero. PAmax1 and PAmax2 represent the axial components of the maximum rolling element load on the main thrust and auxiliary thrust raceways, respectively. According to the deformation compatibility condition, this is located at any angular position. Main thrust

[0076] Axial load on raceway rolling elements:

[0077]

[0078] The total axial force Fa1 on one side of the main thrust raceway is:

[0079]

[0080] Let the contact angle of the rolling element be α, then the maximum load P of the rolling element is... max1 =PA max1 / sinα;

[0081] Fa1 = P max1 ×sinα×Z×J0(ε1);

[0082] Similarly, the total axial force Fa2 on one side of the auxiliary thrust raceway is:

[0083] Fa2=P max2 ×sinα×Z×J0(ε2);

[0084] According to the static equilibrium condition:

[0085]

[0086] The resultant moment M1 on one side of the main thrust raceway is:

[0087]

[0088] Similarly, the resultant moment M2 on one side of the auxiliary thrust raceway is:

[0089]

[0090] The resultant moment of M1 and M2 should be balanced with the applied overturning moment M.

[0091]

[0092] Dividing equation (1-1-2) by (1-1-3) yields:

[0093]

[0094] The above equation is the fundamental equation for analytically solving the load distribution of rolling elements. Since ε1 + ε2 = 1, this equation is actually a univariate nonlinear equation about ε1. For any given set of loads Fa and M, a unique value of ε1 can be obtained. In actual solution, to avoid the difficulty of solving equation (1-1-4), the following table is calculated using the Gaussian numerical integration method based on different values ​​of ε1 and ε2:

[0095]

[0096] As can be seen from this table, The value of is monotonically decreasing; therefore, when the external load is known, it can be determined according to... By referring to the table and using linear interpolation, J0(ε1,ε2) is obtained, and then P is calculated by substituting it into equation (1-1-2). max1 Finally, the rolling element load at any angular position can be calculated using equation (1-1-1). The calculation method is basically similar for slewing bearings with different main and auxiliary thrust raceway parameters, and will not be elaborated here.

[0097] In one embodiment, step one is a numerical solution method:

[0098] Assuming the outer ring remains stationary, when the inner ring of the bearing is simultaneously subjected to axial force Fa, radial force Fr, and overturning moment M, corresponding axial displacement δa, radial displacement δr, and rotation angle θ will be generated; let the angle... It is the angle between the rolling element with the greatest load and the other rolling elements; before the bearing is loaded, the distance between the centers of curvature of the inner and outer ring grooves is the same at any angular position, called the original groove center distance A, then A = (f i +f e -1)×Dw;

[0099] Four-point contact ball slewing bearings have two sets of raceways on both the inner and outer rings; the raceway that primarily bears axial force is called the main thrust raceway, and the other raceway is called the auxiliary thrust raceway. When the bearing is loaded, the center-to-center distance between the main and auxiliary thrust raceways changes.

[0100] At any angle position At this point, the center-to-center distance of the main and auxiliary thrust raceways They were changed to:

[0101]

[0102] In the formula: α0 is the initial contact angle, The total elastic deformation of the steel ball and the main and auxiliary thrust raceways It equals the difference between the center-to-center distance of the groove after the inner ring displacement and the original center-to-center distance, i.e. According to Hertz contact theory, the load Q acting on the steel ball and the total elastic deformation δ between the steel ball and the inner and outer raceways are related as follows: Q = K n ×δ 1.5 ;K n Deformation constant;

[0103] The position of any angle can be determined from this formula. Load on the steel ball:

[0104] Load on the steel balls on the main thrust raceway

[0105] Load on steel balls on the auxiliary thrust raceway

[0106] After the inner ring is displaced, at different angular positions Contact angle of the steel ball at the point The contact angle of the main thrust raceway steel balls will also change. It becomes:

[0107]

[0108]

[0109] Contact angle of the auxiliary thrust raceway steel ball It becomes:

[0110]

[0111] Establish the static equilibrium equations for the inner ring, which state that the forces exerted by all steel balls on the inner ring should be balanced by the external forces:

[0112] The above three equations form a three-dimensional nonlinear equation system with the inner ring displacement as the unknown. When the external load is given, the numerical solution method (Newton-Raphson method) is used to solve the equation system to obtain δa, δr, and θ. Then, the load distribution of the rolling element can be obtained using equations (1-2-1) and (1-2-2).

[0113] In one embodiment, step one: Write a program according to the above method to calculate the load distribution of the axial rollers within the raceway, such as... Figure 2 As shown; enter the main parameter input interface and input the bearing main parameters, such as... Figure 3 As shown; click on Load and Material to enter the load input interface and input the load, such as... Figure 4 As shown; after the calculation is complete, export the FEA data, as follows. Figure 5 As shown.

[0114] In one embodiment, step two: Write an automatic calculation program to drive the three-dimensional finite element analysis software, such as... Figure 6 As shown; after entering the main page, select the bearing type to be calculated, such as... Figure 7 As shown; enter the bearing parameter input interface and input the bearing parameters as required, such as... Figure 8 As shown; after inputting the parameters, confirm the dimensions to generate a 3D model, as shown. Figure 9 As shown;

[0115] In one embodiment, steps three to five involve entering the finite element interface and constraining the generated 3D model in the main program, such as... Figures 10-11 As shown; in the main program, the load is automatically applied to the pre-divided raceways, as follows. Figures 12-13 As shown; after the constraints and loads are created, define the material properties of the model; finally, use the meshing tool provided by the software to divide the model into a mesh with hexahedral elements, such as... Figure 14 As shown.

[0116] After the calculation is complete, view the results, such as... Figure 15 As shown;

[0117] The results show that the maximum stress value of the slewing bearing race is located at the root of the maximum load area in the raceway's middle beam. As the load acting within the raceway gradually decreases along the raceway, the stress at the root of the middle beam also gradually decreases. The local maximum stress calculated according to the fourth strength theory is 405.4 N / mm². 2 This result is consistent with the stress measured during the overall static load and life tests of the bearing, indicating that this analytical method is reasonable. According to the standard requirements for slewing bearing design and material selection, the allowable stress of the slewing bearing races after surface treatment is approximately [σ] = 650 N / mm². 2 The maximum stress obtained from finite element analysis is σ. max= 405.4 N / mm 2 According to the fourth strength theory σ max <[σ], therefore, the design of the center beam thickness of the slewing bearing race is reasonable. Based on this stress distribution, the safety factor of the slewing bearing race can also be directly derived, such as... Figure 16 As shown.

[0118] According to the safety factor distribution diagram of the bearing ring obtained from the finite element analysis, the minimum safety factor of the bearing ring is 1.6, while the user requires a safety factor of 1.2. This indicates that the strength of this bearing component meets the user's requirements. If the analysis and calculation results do not meet the user's requirements, the central beam of the bearing ring will be appropriately thickened, and the size of the oil groove at the root of the beam will be appropriately changed, without affecting the overall design requirements. Then, the analysis and calculation will be performed until the user's requirements are met.

[0119] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0120] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0121] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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 components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0122] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0123] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

Claims

1. A method for calculating the oil groove stress of a three-row cylindrical roller bearing in wind turbines, characterized in that: include Step 1: Based on the forces and bearing parameters of the three-row cylindrical roller bearing, use analytical or numerical methods to calculate the load distribution and roller contact bandwidth of the two rows of rollers in the axial raceway. Step 2: Use 3D software to create a 3D model of the raceway, and divide the loading position on the raceway one by one according to the calculated roller contact bandwidth. Step 3: Import the 3D model into the finite element software, set the material properties, and fix the bottom surface and mounting holes in the finite element software; Step 4: Divide the grid; the positions of the oil grooves and the loading positions cut out by the rollers need to be refined. Step 5: Apply the calculated load for each roller to the pre-divided raceway position one by one, and then perform operational analysis; Step 6: Check the results after the calculation is complete.

2. The method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines according to claim 1, characterized in that, The analytical solution method described in step one: in: This is the angle when the rolling element load is zero. PAmax1 and PAmax2 represent the axial components of the maximum rolling element load on the main thrust and auxiliary thrust raceways, respectively. According to the deformation compatibility condition, this is located at any angular position. Axial load on the rolling elements of the main thrust raceway: The total axial force Fa1 on one side of the main thrust raceway is: Let the contact angle of the rolling element be α, then the maximum load P of the rolling element is... max1 =PA max1 / sinα; Fa1=P max1 ×sinα×Z×J0(ε1); Similarly, the total axial force Fa2 on one side of the auxiliary thrust raceway is: Fa2=P max2 ×sinα×Z×J0(ε2); According to the static equilibrium condition: The resultant moment M1 on one side of the main thrust raceway is: Similarly, the resultant moment M2 on one side of the auxiliary thrust raceway is: The resultant moment of M1 and M2 should be balanced with the applied overturning moment M. Dividing equation (1-1-2) by (1-1-3) yields:

3. The method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines according to claim 1, characterized in that, The numerical solution method described in step one: Assuming the outer ring remains stationary, when the inner ring of the bearing is simultaneously subjected to axial force Fa, radial force Fr, and overturning moment M, corresponding axial displacement δa, radial displacement δr, and rotation angle θ will be generated; let the angle... It is the angle between the rolling element with the greatest load and the other rolling elements; before the bearing is loaded, the distance between the centers of curvature of the inner and outer ring grooves is the same at any angular position, called the original groove center distance A, then A = (f i +f e -1)×Dw; Four-point contact ball slewing bearings have two sets of raceways on both the inner and outer rings; the raceway that mainly bears the axial force is called the main thrust raceway, and the other raceway is called the auxiliary thrust raceway; when the bearing is loaded, the center distance between the main and auxiliary thrust raceways changes. At any angle position At this point, the center-to-center distance of the main and auxiliary thrust raceways They were changed to: In the formula: α0 is the initial contact angle, The total elastic deformation of the steel ball and the main and auxiliary thrust raceways It equals the difference between the center-to-center distance of the groove after the inner ring displacement and the original center-to-center distance, i.e. According to Hertz contact theory, the load Q acting on the steel ball and the total elastic deformation δ between the steel ball and the inner and outer raceways are related as follows: Q = K n ×δ 1.5 ;K n Deformation constant; The position of any angle can be determined from this formula. Load on the steel ball: Load on the steel balls on the main thrust raceway Load on steel balls on the auxiliary thrust raceway After the inner ring is displaced, at different angular positions Contact angle of the steel ball at the point The contact angle of the main thrust raceway steel balls will also change. It becomes: Contact angle of the auxiliary thrust raceway steel ball It becomes: Establish the static equilibrium equations for the inner ring, which state that the forces exerted by all steel balls on the inner ring should be balanced by the external forces: The above three equations form a three-dimensional nonlinear equation system with the inner ring displacement as the unknown quantity. When the external load is given, the numerical solution method of the equation system is used to obtain δa, δr, and θ. Then, the load distribution of the rolling element can be obtained by using equations (1-2-1) and (1-2-2).

4. The method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines according to claim 1, characterized in that, Step 1: Write a program based on the above method to calculate the load distribution of the axial rollers in the raceway; enter the main parameter input interface to input the bearing main parameters; enter the load input interface to input the load; Export the FEA data after the calculation is complete.

5. The method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines according to claim 1, characterized in that, Step 2: Write an automatic calculation program to drive the 3D finite element analysis software; after entering the main page, select the bearing type to be calculated; enter the bearing parameter input interface and input the bearing parameters as required; after the parameters are input, confirm the dimensions and generate the 3D drawing.

6. The method for calculating the oil groove stress of a three-row cylindrical roller bearing for wind turbines according to claim 1, characterized in that, Steps 3 to 5: Enter the finite element interface and constrain the generated 3D model in the main program; automatically apply loads to the pre-divided raceway in the main program; after the constraints and loads are created, define the material properties of the model; finally, use the meshing tool provided by the software to divide the model into a mesh with hexahedral elements.

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