Asymmetric double-row tapered roller main bearing for wind turbine and its design method

Abstract

The present invention discloses an asymmetric double-row tapered roller main bearing for a wind turbine and its design method. The asymmetric double-row tapered roller main bearing for a wind turbine includes a main row tapered roller bearing structure and a secondary row tapered roller bearing structure, and the main row tapered roller bearing structure and the secondary row tapered roller bearing structure are asymmetric. The load-bearing capacity of the main row tapered roller bearing structure is greater than that of the secondary row tapered roller bearing structure, and the two rows of tapered roller bearing structures share a common outer ring. The present invention can effectively solve the problem that the load-bearing capacity of the secondary raceway of the traditional double-row tapered roller main bearing is much greater than the requirement, resulting in waste of load-bearing capacity and cost.

Description

Technical Field

[0001] The present invention relates to the technical field of bearings for wind turbines, and in particular to an asymmetric double-row tapered roller main bearing for a wind turbine and a design method thereof. Background Art

[0002] With the continuous expansion of the wind power industry, the capacity and impeller diameter of wind turbines are gradually increasing, which requires a more powerful transmission chain. As one of the important factors affecting the load-bearing capacity and cost of the transmission chain, the research on the main bearing is of great significance.

[0003] At present, the main bearing forms adopted by wind turbines include single bearing forms such as three-row cylindrical roller bearings, symmetric double-row tapered roller bearings, and paired single-row tapered roller bearings mounted back-to-back or face-to-face. Using a single main bearing can shorten the size of the transmission chain, shorten or remove the main shaft of the wind turbine, and reduce the weight of the main unit. Due to the special load of the wind turbine, the ultimate load and fatigue load on the main raceway side of the double-row tapered roller main bearing are much greater than those on the secondary raceway side. The main raceway and secondary raceway of the traditional symmetric double-row tapered roller main bearing have the same load-bearing capacity, which means that when the main raceway meets the load-bearing capacity requirement, the secondary raceway has a waste of load-bearing capacity, thus causing a waste of cost. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an asymmetric double-row tapered roller main bearing for a wind turbine and a design method thereof, which can effectively solve the problem of waste of load-bearing capacity and cost caused by the fact that the load-bearing capacity of the secondary raceway of the traditional double-row tapered roller main bearing is much greater than the requirement.

[0005] To achieve the above purpose, the technical solution provided by the present invention is: an asymmetric double-row tapered roller main bearing for a wind turbine, the double-row tapered roller main bearing includes a main row tapered roller bearing structure and a secondary row tapered roller bearing structure, and the main row tapered roller bearing structure and the secondary row tapered roller bearing structure are asymmetric, and the load-bearing capacity of the main row tapered roller bearing structure is greater than that of the secondary row tapered roller bearing structure, and the two row tapered roller bearing structures share a common outer ring; wherein, a main raceway cage is provided between the main raceway inner ring and the outer ring of the main row tapered roller bearing structure, a secondary raceway cage is provided between the secondary raceway inner ring and the outer ring of the secondary row tapered roller bearing structure, and main raceway rollers and secondary raceway rollers are respectively provided on the main raceway cage and the secondary raceway cage, and an inner ring spacer is provided between the two raceway inner rings.

[0006] Further, one or more of the roller diameter, roller length, contact angle, roller profile modification, and solid or hollow roller parameters of the main row tapered roller bearing structure are different from those of the secondary row tapered roller bearing structure.

[0007] Design method for asymmetric double-row tapered roller main bearing of wind turbine, including two parts: static strength design and fatigue life design;

[0008] Firstly, establish a load coordinate system with the center of the asymmetric double-row tapered roller main bearing as the coordinate origin. Assume that the asymmetric double-row tapered roller main bearing only bears force F x force. Then, the raceway bearing the positive F x force external load is raceway A, and the other row of raceway is raceway B;

[0009] Among them, the specific steps of the static strength design part are as follows:

[0010] 11) Force calculation of rollers in two rows of asymmetric raceways: According to the relationship between contact deformation and force in Hertz contact theory, calculate the deformation of rollers in two rows of asymmetric raceways to obtain the normal force of each slice roller in two rows of asymmetric raceways;

[0011] 12) Calculation of Hertz contact center stress of rollers in two rows of asymmetric raceways: Substitute the normal force of each slice roller in two rows of asymmetric raceways into the Hertz contact center stress calculation formula to obtain the maximum Hertz contact stress of two rows of asymmetric raceways respectively;

[0012] 13) Calculation of static strength safety factor of raceway: Compare the maximum Hertz contact stress of two rows of asymmetric raceways with the allowable Hertz contact stress to obtain the static strength safety factor of the raceway;

[0013] The specific steps of the fatigue life design part are as follows:

[0014] 21) Calculation of equivalent dynamic load of rollers and rings in two rows of asymmetric raceways: Substitute the normal force of each slice roller in two rows of asymmetric raceways into the rolling element equivalent dynamic load formula to obtain the equivalent dynamic load of two rows of rolling elements; furthermore, calculate the equivalent dynamic load of the corresponding rings according to the equivalent dynamic load of two rows of rolling elements;

[0015] 22) Calculation of basic rated life of raceway: According to the definitions of ISO281 and ISO / TS 16281 standards, use the rated rolling element load formula to calculate the rated rolling element loads of two rows of asymmetric raceways respectively, and combine with the equivalent dynamic load to obtain the basic rated life of the raceway according to the basic rated life formula;

[0016] 23) Calculation of correction factors for rollers in two rows of asymmetric raceways: According to the definitions of ISO281 and ISO / TS 16281 standards, use the equivalent dynamic load of the equivalent rings of each slice roller in two rows of asymmetric raceways to obtain the raceway life correction factors of each slice roller in two rows of asymmetric raceways;

[0017] 24) Calculation of the modified rated life of the bearing: The modified rated life of the bearing is calculated by multiplying the raceway life modification factor by the basic rated life of the bearing according to the modified rated life formula.

[0018] Further, in step 11), the calculation of the forces on the two columns of asymmetric raceway rollers is as follows:

[0019] First, the total load deformation constants of the rolling elements and the inner and outer rings of the two raceways are calculated respectively according to the contact deformation formula of Hertz contact theory.

[0020]

[0021]

[0022] Among them, K A and K B are the total load deformation constants of the rolling elements of raceway A and raceway B with the inner and outer rings respectively, and K iA and K iB are the load deformation constants of the rolling elements of raceway A and raceway B with the inner ring raceway respectively, and K oA and K oB are the load deformation constants of the rolling elements of raceway A and raceway B with the outer ring raceway respectively. n is the Palmgren exponent, which takes the value of 10 / 9 for roller bearings.

[0023] Then, according to the total load deformation constants K A and K B of the rolling elements of the two raceways with the inner and outer rings respectively, the normal acting loads of the rolling elements of raceway A and raceway B with the raceway are calculated respectively.

[0024] Q A = K A δ A n

[0025] Q B = K B δ B n

[0026] Q A and Q B are the normal acting loads of the rolling elements of raceway A and raceway B with the raceway respectively; δ A and δ B are the total normal deformations of the rolling elements of raceway A and raceway B with the raceway respectively.

[0027] The single rolling elements of raceway A and raceway B are cut into m A and m B respectively along the radial direction of the roller.For the slice, the total load deformation constants of each slice of rolling elements in the two raceways become K n,A = K A / m A and K n,B = K B / m B ;

[0028] In the FEA software, each slice of rollers in the two raceways is replaced by a link element connecting the inner and outer rings of the raceway. Their stiffnesses are set according to K n,A , K n,B respectively. The initial displacement of each link element needs to consider the modification amount of the roller profile curve at the position of the corresponding slice of the roller, and then calculate the normal force of each slice of the roller, which are Q A,j,k and Q B,j,k respectively. Among them, Q A,j,k represents the normal force of the j-th rolling element and the k-th slice of the roller in raceway A, j = [1, 2,... Z A , k = [1, 2,... m A , and Z A is the number of rolling elements in raceway A; Q B,j,k represents the normal force of the j-th rolling element and the k-th slice of the roller in raceway B, where j = [1, 2,... Z B , k = [1, 2,... m B , and Z B is the number of rolling elements in raceway B.

[0029] Furthermore, in step 12), the calculation of the Hertz contact center stress of the two columns of asymmetric raceway rollers is specifically as follows:

[0030] The formula for the Hertz contact center stress of a roller bearing is:

[0031]

[0032]

[0033] Among them, b is half of the Hertz contact width, that is, the Hertz contact width is 2b, Q is the normal force between the roller and the raceway, E1 and E2 are the elastic moduli of the rolling element and the raceway respectively; ν1 and ν2 represent the Poisson's ratios of the rolling element and the raceway respectively; l represents the contact roller length corresponding to Q; R1 and R2 represent the radii of curvature of the rolling element and the raceway along the rolling direction of the roller, and the sign of the radius of curvature is positive for the convex surface and negative for the concave surface; σ o represents the maximum Hertz contact center stress;

[0034] Substitute the normal forces Q A,j,k and QB,j,k Substitute into the above Hertz contact center stress formula respectively to find the maximum Hertz contact stresses σ oA,max and σ oB,max of raceway A and raceway B respectively.

[0035] Furthermore, in step 13), the calculation of the static strength safety factor of the raceway is specifically as follows:

[0036] Substitute the maximum Hertz contact stresses σ oA,max and σ oB,max of raceway A and raceway B into the following formulas respectively to calculate the static strength safety factors S A and S B of the two raceways respectively, and take the smaller value as the static strength safety factor of the raceway;

[0037]

[0038] where HV is the Vickers hardness of the raceway surface, [σ] is the allowable Hertz contact stress for static strength, and σ o is σ oA,max or σ oB,max .

[0039] Furthermore, in step 21), the calculation of the equivalent dynamic load of the two rows of asymmetric raceway rollers is specifically as follows:

[0040] According to the definitions in ISO281 and ISO / TS 16281 standards, substitute the normal forces Q A,j,k and Q B,j,k of the j-th rolling element and the k-th roller of raceway A and raceway B into the rolling element equivalent dynamic load formula to obtain the rolling element equivalent dynamic loads of the k-th roller of raceway A and raceway B,

[0041]

[0042]

[0043] where Z A , Z B are the numbers of rolling elements of raceway A and raceway B respectively; e is the life index, which is 4 for the ring rotating relative to the load of the roller bearing and 4.5 for the ring stationary relative to the load of the roller bearing;

[0044] According to the above formulas, distinguish the rings rotating and stationary relative to the load, and calculate the equivalent dynamic load q Ae,i,k of the k-th piece of the inner ring of raceway A, the equivalent dynamic load q Ae,o,k of the k-th piece of the outer ring of raceway A, the equivalent dynamic load q Be,i,k of the k-th piece of the inner ring of raceway B, and the equivalent dynamic load q of the k-th piece of the outer ring of raceway B respectively.Be,o,k , for raceway A, k = [1, 2,... m A , m A is the number of rolling element radial slices along the roller for raceway A, and for raceway B, k = [1, 2,... m B , m B is the number of rolling element radial slices along the roller for raceway B;

[0045] Calculate the equivalent dynamic load of the ring:

[0046] When α > 45°

[0047]

[0048]

[0049] When α ≤ 45°

[0050]

[0051]

[0052] where P A,k , P B,k are the equivalent dynamic loads of the rings corresponding to the k-th slice of rollers of raceway A and raceway B, respectively.

[0053] Furthermore, in step 22), the calculation of the basic rated life of the raceway is as follows:

[0054] Solve for the rated rolling element dynamic load q Ac,i of the inner ring of raceway A, the rated rolling element dynamic load q Ac,o of the outer ring of raceway A, the rated rolling element dynamic load q Bc,i of the inner ring of raceway B, and the rated rolling element dynamic load q Bc,o of the outer ring of raceway B, respectively, according to the rated rolling element load formula applicable to the inner ring and the rated rolling element load applicable to the outer ring,

[0055] The rated rolling element load formula is:

[0056]

[0057]

[0058] where q Ac is the rated dynamic load of the rolling element slices of the inner or outer ring of raceway A, i.e., the upper symbol applies to the inner ring and the lower symbol applies to the outer ring; q Bc is the rated dynamic load of the rolling element slices of the inner or outer ring of raceway B, i.e., the upper symbol applies to the inner ring and the lower symbol applies to the outer ring; γ A is a dimensionless parameter of raceway A, γ B is the dimensionless parameter of raceway B. b m,A is the material and process correction factor of the rated dynamic load of raceway A. When α A ≤ 45°, b m,A = 1.3. When 45 < α A ≤ 90°, b m,A = 1; b m,B is the material and process correction factor of the rated dynamic load of raceway B. When α B ≤ 45°, b m,B = 1.3. When 45 < α B ≤ 90°, b m,B = 1; λ A , η A are the correction factors of the rated dynamic load of raceway A for structure, contact mode, and guiding mode. When α A ≤ 45°, λ A = 0.83, η A = 1; when 45 < α A ≤ 90°, λ A = 0.73. λ B , η B are the correction factors of the rated dynamic load of raceway A for structure, contact mode, and guiding mode. When α B ≤ 45°, λ B = 0.83, η B = 1; when 45 < α B ≤ 90°, λ B = 0.73. D w,A , D w,B are the roller diameters of raceway A and raceway B respectively; d wp,A , d wp,B are the roller pitch circle diameters of raceway A and raceway B respectively; L we,A , L we,B are the effective lengths of the rollers of raceway A and raceway B respectively; If the forces on the rolling elements are fully considered or verified, λ A , λ B can be amplified, with a maximum of 1.

[0059] Through the dynamic load q Ac,i of the rated sliced rolling elements of the inner ring of raceway A, the dynamic load q Ac,o of the rated sliced rolling elements of the outer ring of raceway A, the dynamic load q Bc,i of the rated sliced rolling elements of the inner ring of raceway B, and the dynamic load q Bc,o of the rated sliced rolling elements of the outer ring of raceway B, combined with the equivalent dynamic load q Ae,i,k, the equivalent dynamic load q of the k-th piece of the outer ring of raceway A Ae,o,k , the equivalent dynamic load q of the k-th piece of the inner ring of raceway B Be,i,k and the equivalent dynamic load q of the k-th piece of the outer ring of raceway B Be,o,k are substituted into the basic rating life formula of the raceway to calculate the basic rating life L10 of the raceway:

[0060]

[0061] Among them, for raceway A, k = [1, 2,... m A , m A is the number of rolling element radial slices of raceway A along the roller, and for raceway B, k = [1, 2,... m B , m B is the number of rolling element radial slices of raceway B along the roller.

[0062] Furthermore, in step 23), the calculation of the correction coefficient of the two rows of asymmetric raceway rollers is specifically as follows:

[0063] According to the raceway life correction coefficient formula defined in ISO281 and ISO / TS 16281 standards:

[0064] When α ≤ 45°

[0065] When 0.1 ≤ κ < 0.4

[0066] When 0.4 ≤ κ < 1

[0067] When 1 ≤ κ < 4

[0068] When 45 < α ≤ 90°

[0069] When 0.1 ≤ κ < 0.4

[0070] When 0.4 ≤ κ < 1

[0071] When 1 ≤ κ < 4

[0072] Among them, aiso is the correction coefficient, κ is the lubricant viscosity ratio, e c is the lubricant contamination factor, C u is the fatigue load life, and P is the equivalent dynamic load of the ring;

[0073] The equivalent dynamic loads P A,k and P B,k of the k-th piece of rollers of raceway A and raceway B are respectively substituted for the equivalent dynamic load P of the ring in the formula to obtain the life correction coefficient aiso of the k-th piece of rolling elements of raceway A respectivelyA,k 、Roller life correction factor aiso for the k-th rolling element of raceway B B,k , for raceway A, k = [1, 2,... m A , m A is the number of radial slices of the rolling elements of raceway A along the roller, for raceway B, k = [1, 2,... m B , m B is the number of radial slices of the rolling elements of raceway B along the roller.

[0074] Furthermore, in step 24), the calculation of the corrected rated life of the bearing is specifically as follows:

[0075] Combining the correction factors of the two rows of asymmetric raceway rollers and the basic rated life of the raceway, and obtaining the corrected rated life L10r of the bearing according to the corrected rated life formula,

[0076]

[0077] where, aiso A,k is the roller life correction factor for the k-th piece of raceway A, aiso B,k is the roller life correction factor for the k-th piece of raceway B, q Ac,i is the dynamic load of the rated sliced rolling elements of the inner ring of raceway A, q Ac,o is the dynamic load of the rated sliced rolling elements of the outer ring of raceway A, q Bc,i is the dynamic load of the rated sliced rolling elements of the inner ring of raceway B, q Bc,o is the dynamic load of the rated sliced rolling elements of the outer ring of raceway B, q Ae,i,k is the equivalent dynamic load of the k-th piece of the inner ring of raceway A, q Ae,o,k is the equivalent dynamic load of the k-th piece of the outer ring of raceway A, q Be,i,k is the equivalent dynamic load of the k-th piece of the inner ring of raceway B, q Be,o,k is the equivalent dynamic load of the k-th piece of the outer ring of raceway B, m A is the number of radial slices of the rolling elements of raceway A along the roller, m B is the number of radial slices of the rolling elements of raceway B along the roller.

[0078] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0079] 1. The asymmetric double-row tapered roller main bearing of the present invention can effectively improve the utilization rate of the bearing load-carrying capacity. At the same time, on the premise of meeting the design requirements of the load-carrying capacity, the material cost of the main bearing can be reduced by 10-20% year-on-year, and the greater the power and the larger the impeller of the fan, the more significant the cost reduction.

[0080] 2. For the asymmetric double-row tapered roller main bearing of the present invention, the effect of the upwind fan is more significant than that of the downwind fan. Description of the Drawings

[0081] Figure 1 This is a sectional view of the asymmetric double-row tapered roller main bearing of the present invention.

[0082] Figure 2 This is the load coordinate system of the asymmetric double-row tapered roller main bearing of the present invention. Detailed implementation manners

[0083] The present invention will be further described below in conjunction with specific embodiments.

[0084] As Figure 1 shown, for the asymmetric double-row tapered roller main bearing of the wind turbine unit in this embodiment, the double-row tapered roller main bearing includes a main row tapered roller bearing structure and a secondary row tapered roller bearing structure, and the main row tapered roller bearing structure and the secondary row tapered roller bearing structure are asymmetric, that is, one or more of the roller diameter, roller length, contact angle, roller profile modification, and roller hollow or solid parameters of the main row tapered roller bearing structure are different from those of the secondary row tapered roller bearing structure, and it is ensured that the load-bearing capacity of the main row tapered roller bearing structure is greater than that of the secondary row tapered roller bearing structure. The two rows of tapered roller bearing structures share a common outer ring 3; wherein, a main raceway cage 102 is provided between the main raceway inner ring 101 of the main row tapered roller bearing structure and the outer ring 3, a secondary raceway cage 202 is provided between the secondary raceway inner ring 201 of the secondary row tapered roller bearing structure and the outer ring 3, and main raceway rollers 103 and secondary raceway rollers 203 are respectively provided on the main raceway cage 102 and the secondary raceway cage 202, and an inner ring spacer 4 is provided between the two raceway inner rings.

[0085] In addition, the installation direction of the main row tapered roller bearing structure is related to the type of the wind power generating unit. Assuming that the main row tapered roller bearing structure is raceway A and the secondary row tapered roller bearing structure is raceway B, when the impeller of the unit is installed on the inner ring, raceway A is in the oncoming wind direction; when the impeller is installed on the outer ring, raceway B is in the oncoming wind direction.

[0086] The following is the design method of the above-mentioned asymmetric double-row tapered roller main bearing of the wind turbine unit in this embodiment, including two parts: static strength design and fatigue life design.

[0087] As Figure 2 shown, first, a load coordinate system is established with the center of the asymmetric double-row tapered roller main bearing as the coordinate origin. Assuming that the asymmetric double-row tapered roller main bearing only bears force F x force, then the raceway bearing the positive F x force external load is raceway A, and the other raceway is raceway B.

[0088] The specific steps of the static strength design part are as follows:

[0089] 11) Force calculation of the rollers in two asymmetric raceways: According to the relationship between contact deformation and force in Hertz contact theory, the normal force of each slice roller in the two asymmetric raceways is obtained by calculating the deformation of the rollers in the two asymmetric raceways.

[0090] The calculation process is as follows:

[0091] First, calculate the total load deformation constants of the rolling elements and the inner and outer rings of the two raceways respectively according to the contact deformation formula of Hertz contact theory.

[0092]

[0093]

[0094] Among them, K A , K B are the total load deformation constants of the rolling elements of raceway A, the rolling elements of raceway B and the inner and outer rings respectively. K iA , K iB are the load deformation constants of the rolling elements of raceway A, the rolling elements of raceway B and the inner raceway respectively. K oA , K oB are the load deformation constants of the rolling elements of raceway A, the rolling elements of raceway B and the outer raceway respectively. n is the Palmgren index, and the value for roller bearings is 10 / 9.

[0095] Then, according to the total load deformation constants K A and K B of the rolling elements of the two raceways and the inner and outer rings, calculate the normal acting loads of the rolling elements of raceway A, the rolling elements of raceway B and the raceway respectively.

[0096] Q A =K A δ A n

[0097] Q B =K B δ B n

[0098] Q A , Q B are the normal acting loads of the rolling elements of raceway A, the rolling elements of raceway B and the raceway respectively; δ A , δ B are the total normal deformations of the rolling elements of raceway A, the rolling elements of raceway B and the raceway respectively.

[0099] Cut the single rolling elements of raceway A and raceway B along the radial direction of the roller into m A , m BFor each slice of the rolling elements in the two raceways, the total load deformation constants of each slice of the rolling elements in the two raceways become K n,A = K A / m A and K n,B = K B / m B ;

[0100] In the FEA software, each slice of the rollers in the two raceways is replaced by a link element that connects the inner and outer rings of the raceway. Their stiffnesses are set according to K n,A , K n,B respectively. The initial displacement of each link element needs to consider the modification amount of the roller profile curve at the position of the corresponding slice of the roller, and then calculate the normal force of each slice of the roller, which are Q A,j,k and Q B,j,k respectively. Among them, Q A,j,k represents the normal force of the j-th rolling element and the k-th slice of the roller in raceway A, where j = [1, 2,... Z A , k = [1, 2,... m A , and Z A is the number of rolling elements in raceway A; Q B,j,k represents the normal force of the j-th rolling element and the k-th slice of the roller in raceway B, where j = [1, 2,... Z B , k = [1, 2,... m B , and Z B is the number of rolling elements in raceway B.

[0101] 12) Calculation of the Hertz contact center stress of the rollers in two non-symmetric raceways: By substituting the normal forces of each slice of the rollers in the two non-symmetric raceways into the Hertz contact center stress calculation formula, the maximum Hertz contact stresses of the two non-symmetric raceways are obtained respectively;

[0102] The calculation process is as follows:

[0103] The formula for the Hertz contact center stress of a roller bearing is:

[0104]

[0105]

[0106] Among them, b is half of the Hertz contact width, that is, the Hertz contact width is 2b, Q is the normal force between the roller and the raceway, E1 and E2 are the elastic moduli of the rolling element and the raceway respectively; ν1 and ν2 represent the Poisson's ratios of the rolling element and the raceway respectively; l represents the contact roller length corresponding to Q; R1 and R2 represent the curvature radii of the rolling element and the raceway along the rolling direction of the roller, and the sign of the curvature radius is positive for the convex surface and negative for the concave surface; σ oRepresents the maximum stress at the Hertz contact center;

[0107] Substitute the normal force Q of each rolling element of raceway A and raceway B A,j,k , Q B,j,k into the above Hertz contact center stress formula respectively, and calculate the maximum Hertz contact stresses σ oA,max and σ oB,max of raceway A and raceway B respectively.

[0108] 13) Calculation of the static strength safety factor of the raceway: Compare the maximum Hertz contact stress of the two non-symmetrical raceways with the allowable Hertz contact stress to obtain the static strength safety factor of the raceway;

[0109] The calculation process is as follows:

[0110] Substitute the maximum Hertz contact stresses σ oA,max and σ oB,max of raceway A and raceway B into the following formula respectively, and calculate the static strength safety factors S A and S B of the two raceways respectively, and take the smaller value as the static strength safety factor of the raceway;

[0111]

[0112] where HV is the Vickers hardness of the raceway surface, [σ] is the allowable Hertz contact stress for static strength, and σ o is σ oA,max or σ oB,max .

[0113] The specific steps of the fatigue life design part are as follows:

[0114] 21) Calculation of the equivalent dynamic load of the rollers and rings of the two non-symmetrical raceways: Substitute the normal force of each slice of the rollers of the two non-symmetrical raceways into the rolling element equivalent dynamic load formula to obtain the equivalent dynamic load of the two rows of rolling elements; and then calculate the equivalent dynamic load of the corresponding rings according to the equivalent dynamic load of the two rows of rolling elements;

[0115] The calculation process is as follows:

[0116] According to the definitions of ISO281 and ISO / TS 16281 standards, substitute the normal forces Q A,j,k and Q B,j,k of the jth rolling element and the kth slice of the rollers of raceway A and raceway B into the rolling element equivalent dynamic load formula respectively, and obtain the rolling element equivalent dynamic load of the kth slice of the rollers of raceway A and raceway B,

[0117]

[0118]

[0119] Among them, Z A and Z B are the numbers of rolling elements in raceway A and raceway B respectively; e is the life index, which is 4 for the ring rotating relative to the load of a roller bearing and 4.5 for the ring stationary relative to the load of a roller bearing;

[0120] According to the above formula, distinguish the rings rotating and stationary relative to the load, and calculate the equivalent dynamic load q of the k-th slice of the inner ring of raceway A Ae,i,k , the equivalent dynamic load q of the k-th slice of the outer ring of raceway A Ae,o,k , the equivalent dynamic load q of the k-th slice of the inner ring of raceway B Be,i,k , the equivalent dynamic load q of the k-th slice of the outer ring of raceway B Be,o,k , for raceway A, k = [1, 2,... m A , m A is the number of slices of the rolling elements of raceway A along the radial section of the rollers. For raceway B, k = [1, 2,... m B , m B is the number of slices of the rolling elements of raceway B along the radial section of the rollers;

[0121] Calculate the equivalent dynamic load of the ring:

[0122] When α > 45°

[0123]

[0124]

[0125] When α ≤ 45°

[0126]

[0127]

[0128] Among them, P A,k and P B,k are the equivalent dynamic loads of the rings equivalent to the k-th slice of rollers in raceway A and raceway B respectively.

[0129] 22) Calculate the basic rated life of the raceway: According to the definitions in ISO281 and ISO / TS 16281 standards, use the rated rolling element load formula to calculate the rated rolling element loads of the two non-symmetric raceways respectively, and combine with the equivalent dynamic load to obtain the basic rated life of the raceway according to the basic rated life formula;

[0130] The calculation process is as follows:

[0131] Solve the rated rolling element dynamic load q of the rated slices of the inner ring of raceway A respectively according to the rated rolling element load formula applicable to the inner ring and the rated rolling element load applicable to the outer ringAc,i 、Dynamic load of the rolling elements per slice of the outer ring of raceway A, q Ac,o 、Dynamic load of the rolling elements per slice of the inner ring of raceway B, q Bc,i and dynamic load of the rolling elements per slice of the outer ring of raceway B, q Bc,o ,

[0132] The formula for the rated rolling element load is:

[0133]

[0134]

[0135] Where q Ac is the rated dynamic load per slice of the rolling elements of the inner or outer ring of raceway A, i.e., the upper symbol applies to the inner ring and the lower symbol applies to the outer ring; q Bc is the rated dynamic load per slice of the rolling elements of the inner or outer ring of raceway B, i.e., the upper symbol applies to the inner ring and the lower symbol applies to the outer ring; γ A is the dimensionless parameter of raceway A, γ B is the dimensionless parameter of raceway B, b m,A is the correction factor for the material and process of the rated dynamic load of raceway A. When α A ≤45°, b m,A = 1.3. When 45 < α A ≤90°, b m,A = 1; b m,B is the correction factor for the material and process of the rated dynamic load of raceway B. When α B ≤45°, b m,B = 1.3. When 45 < α B ≤90°, b m,B = 1; λ A , η A are the correction factors for the structure, contact mode, and guiding mode of the rated dynamic load of raceway A. When α A ≤45°, λ A = 0.83, η A = 1; when 45 < α A ≤90°, λ A = 0.73, λ B , η B are the correction factors for the structure, contact mode, and guiding mode of the rated dynamic load of raceway A. When α B ≤45°, λ B = 0.83, η B = 1; when 45 < α B ≤90°, λ B = 0.73, D w,A and D w,B are the roller diameters of raceway A and raceway B respectively; d wp,A and d wp,B are the roller pitch circle diameters of raceway A and raceway B respectively; L we,A and L we,B are the effective lengths of the rollers of raceway A and raceway B respectively; If the forces on the rolling elements are fully considered or verified, λ A and λ B can be enlarged, with a maximum of 1;

[0136] Through the dynamic load q of the rolling elements of the rated slice of the inner ring of raceway A Ac,i , the dynamic load q of the rolling elements of the rated slice of the outer ring of raceway A Ac,o , the dynamic load q of the rolling elements of the rated slice of the inner ring of raceway B Bc,i and the dynamic load q of the rolling elements of the rated slice of the outer ring of raceway B Bc,o Combined with the equivalent dynamic load q of the k-th slice of the inner ring of raceway A Ae,i,k , the equivalent dynamic load q of the k-th slice of the outer ring of raceway A Ae,o,k , the equivalent dynamic load q of the k-th slice of the inner ring of raceway B Be,i,k and the equivalent dynamic load q of the k-th slice of the outer ring of raceway B Be,o,k Substitute into the basic rated life formula of the raceway to calculate the basic rated life L10 of the raceway:

[0137]

[0138] Among them, for raceway A, k = [1, 2,...m A , m A is the number of radial slices of the rolling elements of raceway A along the roller, for raceway B, k = [1, 2,...m B , m B is the number of radial slices of the rolling elements of raceway B along the roller.

[0139] 23) Calculation of the roller correction factor for two non-symmetric raceways: According to the definitions in ISO281 and ISO / TS 16281 standards, the raceway life correction factor for each slice of the two non-symmetric raceways is obtained by using the equivalent dynamic load of the equivalent rings of each slice of the two non-symmetric raceways;

[0140] The calculation process is as follows:

[0141] According to the raceway life correction factor formula defined in ISO281 and ISO / TS 16281 standards:

[0142] When α ≤ 45°

[0143] When 0.1 ≤ κ < 0.4

[0144] When 0.4 ≤ κ < 1

[0145] When 1 ≤ κ < 4

[0146] When 45 < α ≤ 90°

[0147] When 0.1 ≤ κ < 0.4

[0148] When 0.4 ≤ κ < 1

[0149] When 1 ≤ κ < 4

[0150] Where aiso is the correction coefficient, κ is the lubricant viscosity ratio, e c is the lubricant contamination factor, C u is the fatigue load life, and P is the equivalent dynamic load of the ring;

[0151] The equivalent dynamic loads P A,k and P B,k of the k-th roller of raceway A and raceway B are respectively substituted for the equivalent dynamic load P of the ring in the formula, and the life correction coefficients aiso A,k of the k-th rolling element of raceway A and aiso B,k of the k-th rolling element of raceway B are obtained respectively. For raceway A, k = [1, 2,... m A , where m A is the number of radial slices of the rolling elements of raceway A along the roller. For raceway B, k = [1, 2,... m B , where m B is the number of radial slices of the rolling elements of raceway B along the roller.

[0152] 24) Calculation of the corrected rated life of the bearing: The corrected rated life of the bearing is calculated by multiplying the raceway life correction coefficient by the basic rated life of the bearing according to the corrected rated life formula.

[0153] The calculation process is as follows:

[0154] Combining the correction coefficients of the two columns of rollers with asymmetric raceways and the basic rated life of the raceway, and obtaining the corrected rated life L10r of the bearing according to the corrected rated life formula,

[0155]

[0156] Where aiso A,k is the life correction coefficient of the k-th rolling element of raceway A, aiso B,k is the life correction coefficient of the k-th rolling element of raceway B, and q Ac,iThe rated slice rolling element dynamic load of the inner ring of raceway A, q Ac,o The rated slice rolling element dynamic load of the outer ring of raceway A, q Bc,i The rated slice rolling element dynamic load of the inner ring of raceway B, q Bc,o The rated slice rolling element dynamic load of the outer ring of raceway B, q Ae,i,k The equivalent dynamic load of the k-th slice of the inner ring of raceway A, q Ae,o,k The equivalent dynamic load of the k-th slice of the outer ring of raceway A, q Be,i,k The equivalent dynamic load of the k-th slice of the inner ring of raceway B, q Be,o,k The equivalent dynamic load of the k-th slice of the outer ring of raceway B, m A The number of slices of the rolling elements of raceway A along the radial direction of the rollers, m B The number of slices of the rolling elements of raceway B along the radial direction of the rollers.

[0157] The above-described embodiments are only the preferred embodiments of the present invention, and do not limit the scope of implementation of the present invention. Therefore, all changes made according to the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. Design method for asymmetric double-row tapered roller main bearing of wind turbine, characterized in that: The double-row tapered roller main bearing includes a main-row tapered roller bearing structure and a sub-row tapered roller bearing structure, and the main-row tapered roller bearing structure and the sub-row tapered roller bearing structure are asymmetric. The load-carrying capacity of the main-row tapered roller bearing structure is greater than that of the sub-row tapered roller bearing structure. The two rows of tapered roller bearing structures share a common outer ring. One or more of the roller diameter, roller length, contact angle, roller profile modification, and roller hollow or solid parameters of the main-row tapered roller bearing structure are different from those of the sub-row tapered roller bearing structure. Among them, a main raceway cage is provided between the inner ring and the outer ring of the main raceway of the main-row tapered roller bearing structure, and a sub-raceway cage is provided between the inner ring and the outer ring of the sub-raceway of the sub-row tapered roller bearing structure. Main raceway rollers and sub-raceway rollers are respectively provided on the main raceway cage and the sub-raceway cage, and an inner ring spacer is provided between the two inner raceways. The design method of the asymmetric double-row tapered roller main bearing of the wind turbine includes two parts: static strength design and fatigue life design. First, a load coordinate system is established with the center of the asymmetric double-row tapered roller main bearing as the coordinate origin. Assume that this asymmetric double-row tapered roller main bearing only bears force F x force. Then, the raceway that bears the positive F x force external load is raceway A, and the other row of raceways is raceway B; The specific steps of the static strength design part are as follows: 11) Force calculation of two rows of asymmetric raceway rollers: According to the relationship between contact deformation and force in Hertz contact theory, the normal force of each slice roller of the two rows of asymmetric raceway rollers is obtained by calculating the deformation of the two rows of asymmetric raceway rollers. 12) Calculation of Hertz contact center stress of two rows of asymmetric raceway rollers: By substituting the normal force of each slice roller of the two rows of asymmetric raceway rollers into the Hertz contact center stress calculation formula, the maximum Hertz contact stress of the two rows of asymmetric raceways is obtained respectively. 13) Calculation of the static strength safety factor of the raceway: Compare the maximum Hertz contact stress of the two rows of asymmetric raceways with the allowable Hertz contact stress to obtain the static strength safety factor of the raceway. The specific steps of the fatigue life design part are as follows: 21) Calculation of equivalent dynamic load of two rows of asymmetric raceway rollers and rings: By substituting the normal force of each slice roller of the two rows of asymmetric raceway rollers into the rolling element equivalent dynamic load formula, the equivalent dynamic load of the two rows of rolling elements is obtained. Furthermore, the equivalent dynamic load of the corresponding rings is calculated respectively according to the equivalent dynamic load of the two rows of rolling elements. 22) Calculation of the basic rated life of the raceway: According to the definitions of ISO281 and ISO / TS16281 standards, the rated rolling element load of the two rows of asymmetric raceways is calculated respectively by using the rated rolling element load formula, and the basic rated life of the raceway is obtained according to the basic rated life formula in combination with the equivalent dynamic load. 23) Calculation of correction factors for two rows of asymmetric raceway rollers: According to the definitions of ISO281 and ISO / TS16281 standards, the raceway life correction factors of each slice roller of the two rows of asymmetric raceways are obtained by using the equivalent dynamic load of the equivalent rings of each slice roller of the two rows of asymmetric raceways. 24) Calculation of the corrected rated life of the bearing: By using the raceway life correction factor and the basic rated life of the bearing according to the corrected rated life formula, the corrected rated life of the bearing is calculated.

2. The design method of the asymmetric double-row tapered roller main bearing of a wind turbine according to claim 1, characterized in that: In step 11), the force calculation of the two rows of asymmetric raceway rollers is specifically as follows. First, calculate the total load deformation constants of the rolling elements and the inner and outer rings of the two raceways respectively according to the contact deformation formula of Hertz contact theory. Among them, K A and K B are the total load deformation constants of the rolling elements of raceway A, the rolling elements of raceway B and the inner and outer rings respectively. K iA and K iB are the load deformation constants of the rolling elements of raceway A, the rolling elements of raceway B and the corresponding inner raceway respectively. K oA and K oB are the load deformation constants of the rolling elements of raceway A, the rolling elements of raceway B and the outer raceway respectively. n is the Palmgren exponent, which takes the value of 10 / 9 for roller bearings; Then, according to the total load deformation constants K of the rolling elements of the two raceways with the inner and outer rings A and K B calculate the normal acting loads of the rolling elements of raceway A, the rolling elements of raceway B and the raceway respectively Q A = K A δ A n Q B = K B δ B n Q A and Q B are the normal acting loads of the rolling elements of raceway A, the rolling elements of raceway B and the raceway respectively; δ A and δ B are the total normal deformations of the rolling elements of raceway A, the rolling elements of raceway B and the raceway respectively; The single rolling elements of raceway A and raceway B are each cut into m A 、m B pieces along the radial direction of the rollers, then the total load deformation constants of each piece of rolling elements in the two raceways become K n,A = K A / m A and K n,B = K B / m B ; In the FEA software, each roller of the two raceways is replaced by a link unit connecting the inner and outer rings of the raceway, and its stiffness is set according to K n,A , K n,B . The initial displacement of each link unit needs to consider the modification amount of the roller profile curve at the position of the corresponding sliced roller, and then calculate the normal force of each sliced roller, which are Q A,j,k and Q B,j,k , respectively. Among them, Q A,j,k represents the normal force of the j-th rolling element and the k-th roller of raceway A, where j = [1, 2,... Z A , k = [1, 2,... m A , and Z A is the number of rolling elements of raceway A; Q B,j,k represents the normal force of the j-th rolling element and the k-th roller of raceway B, where j = [1, 2,... Z B , k = [1, 2,... m B , and Z B is the number of rolling elements of raceway B.

3. The design method of the asymmetric double-row tapered roller main bearing of a wind turbine according to claim 1, characterized in that: In step 12), the calculation of the Hertz contact center stress of the two rows of asymmetric raceway rollers is as follows: The formula for the Hertz contact center stress of a roller bearing is: where b is half of the Hertz contact width, i.e., the Hertz contact width is 2b, Q is the normal force between the roller and the raceway, E1 and E2 are the elastic moduli of the rolling element and the raceway respectively; ν1 and ν2 represent the Poisson's ratios of the rolling element and the raceway respectively; l represents the contact roller length corresponding to Q; R1 and R2 represent the radii of curvature of the rolling element and the raceway along the rolling direction of the roller respectively, and the sign of the radius of curvature is positive for the convex surface and negative for the concave surface; σ o represents the maximum stress at the Hertz contact center; Substitute the normal force Q of each rolling element of raceway A and raceway B A,j,k , Q B,j,k into the above Hertz contact center stress formula respectively, and find the maximum Hertz contact stresses σ oA,max and σ oB,max of raceway A and raceway B respectively.

4. The design method of the asymmetric double-row tapered roller main bearing of a wind turbine according to claim 1, characterized in that: In step 13), the calculation of the static strength safety factor of the raceway is as follows: Substitute the maximum Hertz contact stresses σ of raceway A and raceway B oA,max and σ oB,max into the following formulas respectively to calculate the static strength safety factors S A and S B , and take the smaller value as the static strength safety factor of the raceway; Among them, HV is the Vickers hardness of the raceway surface, [σ] is the allowable Hertz contact stress for static strength, and σ o is σ oA,max or σ oB,max .

5. The design method of the asymmetric double-row tapered roller main bearing of a wind turbine according to claim 1, wherein: In step 21), the calculation of the equivalent dynamic load of the two rows of asymmetric raceway rollers is as follows: According to the definitions in ISO 281 and ISO / TS 16281 standards, the normal forces Q of the j-th rolling element and the k-th roller of raceway A and raceway B are respectively A,j,k and Q B,j,k are substituted into the equivalent dynamic load formula of the rolling element to obtain the equivalent dynamic load of the rolling element of the k-th roller of raceway A and raceway B Among them, Z A , Z B are the numbers of rolling elements of raceway A and raceway B respectively; e is the life index, which is 4 for the ring rotating relative to the load of a roller bearing and 4.5 for the ring stationary relative to the load of a roller bearing; According to the above formula, the equivalent dynamic load q of the k-th piece of the inner ring of raceway A is calculated separately for the relatively loaded rotating and stationary rings Ae, i ,k , the equivalent dynamic load q of the k-th piece of the outer ring of raceway A Ae,o,k , the equivalent dynamic load q of the k-th piece of the inner ring of raceway B Be,i,k , the equivalent dynamic load q of the k-th piece of the outer ring of raceway B Be,o,k , for raceway A, k = [1, 2,... m A , m A is the number of radial slices of the rolling elements of raceway A along the roller, for raceway B, k = [1, 2,... m B , m B is the number of radial slices of the rolling elements of raceway B along the roller; Calculate the equivalent dynamic load of the ring: When α > 45° When α ≤ 45° Among which P A,k and P B,k are respectively the equivalent ring dynamic load of the kth roller of raceway A and raceway B.

6. The design method of the asymmetric double-row tapered roller main bearing of a wind turbine according to claim 1, characterized in that: In step 22), the calculation of the basic rated life of the raceway is as follows: Solve the rated rolling element dynamic load q of the inner ring of the raceway A, the rated rolling element dynamic load q of the outer ring of the raceway A, the rated rolling element dynamic load q of the inner ring of the raceway B, and the rated rolling element dynamic load q of the outer ring of the raceway B respectively according to the rated rolling element load formula applicable to the inner ring and the rated rolling element load formula applicable to the outer ring. Ac,i and the rated rolling element dynamic load q of the outer ring of the raceway A Ac,o and the rated rolling element dynamic load q of the inner ring of the raceway B Bc,i and the rated rolling element dynamic load q of the outer ring of the raceway B Bc,o , The formula for the rated rolling element load is: wherein, q Ac is the rated dynamic load of the rolling element slice of the inner or outer ring of raceway A, that is, the upper symbol applies to the inner ring and the lower symbol applies to the outer ring; q Bc is the rated dynamic load of the rolling element slice of the inner or outer ring of raceway B, that is, the upper symbol applies to the inner ring and the lower symbol applies to the outer ring; γ A is the dimensionless parameter of raceway A, γ B is the dimensionless parameter of raceway B, b m,A is the correction coefficient of the rated dynamic load material and process of raceway A. When α A ≤45°, b m,A = 1.

3. When 45 < α A ≤90°, b m,A = 1; b m,B is the correction coefficient of the rated dynamic load material and process of raceway B. When α B ≤45°, b m,B = 1.

3. When 45 < α B ≤90°, b m,B = 1; λ A , η A are the correction coefficients of the rated dynamic load structure, contact mode, and guiding mode of raceway A. When α A ≤45°, λ A = 0.83, η A = 1. When 45 < α A ≤90°, λ A = 0.73, λ B , η B are the correction coefficients of the rated dynamic load structure, contact mode, and guiding mode of raceway A. When α B ≤45°, λ B = 0.83, η B = 1. When 45 < α B ≤90°, λ B = 0.73, D w,A 、D w,B are the roller diameters of raceway A and raceway B respectively; d wp,A 、d wp,B are the roller pitch circle diameters of raceway A and raceway B respectively; L we,A 、L we,B are the effective lengths of the rollers of raceway A and raceway B respectively; If the forces on the rolling elements are fully considered or verified, λ A 、λ B can be amplified, with a maximum of 1; Rated slice rolling element dynamic load q of the inner ring of raceway A Ac,i 、Rated slice rolling element dynamic load q of the outer ring of raceway A Ac,o 、Rated slice rolling element dynamic load q of the inner ring of raceway B Bc,i And rated slice rolling element dynamic load q of the outer ring of raceway B Bc,o Combined with the equivalent dynamic load q of the k-th slice of the inner ring of raceway A Ae,i,k 、Equivalent dynamic load q of the k-th slice of the outer ring of raceway A Ae,o,k 、Equivalent dynamic load q of the k-th slice of the inner ring of raceway B Be,i,k And equivalent dynamic load q of the k-th slice of the outer ring of raceway B Be,o,k Substitute into the basic rated life formula of the raceway to calculate the basic rated life L10 of the raceway: Among them, for raceway A, k = [1, 2,... m A , m A is the number of rolling elements of raceway A sliced along the radial direction of the roller. For raceway B, k = [1, 2,... m B , m B is the number of rolling elements of raceway B sliced along the radial direction of the roller.

7. The design method of the asymmetric double-row tapered roller main bearing of a wind turbine according to claim 1, characterized in that: In step 23), the calculation of the correction factor of the two rows of asymmetric raceway rollers is as follows: According to the formula for the raceway life correction factor defined in ISO281 and ISO / TS16281 standards: When α ≤ 45° When When When When 45 < α ≤ 90° When When When where aiso is the correction coefficient, κ is the lubricant viscosity ratio, and e c is the lubricant contamination factor, C u is the fatigue load life, and P is the equivalent dynamic load of the ring; The equivalent dynamic load P of the raceway A and the k-th roller of the raceway B A,k , P B,k are respectively substituted for the equivalent dynamic load P of the raceway in the formula to obtain the life correction factor aiso of the k-th rolling element of the raceway A A,k and the life correction factor aiso of the k-th rolling element of the raceway B B,k . For the raceway A, k = [1, 2,... m A , where m A is the number of radial slices of the rolling elements of the raceway A along the roller. For the raceway B, k = [1, 2,... m B , where m B is the number of radial slices of the rolling elements of the raceway B along the roller.

8. The design method of the asymmetric double-row tapered roller main bearing of a wind turbine according to claim 1, characterized in that: In step 24), the calculation of the corrected rated life of the bearing is as follows: Combining the correction factor of the two rows of asymmetric raceway rollers and the basic rated life of the raceway, and obtaining the corrected rated life L10r of the bearing according to the corrected rated life formula. Among them, aiso A,k is the life correction coefficient of the kth rolling element in raceway A, aiso B,k is the life correction coefficient of the kth rolling element in raceway B, q Ac,i is the dynamic load of the rated sliced rolling elements of the inner ring in raceway A, q Ac,o is the dynamic load of the rated sliced rolling elements of the outer ring in raceway A, q Bc,i is the dynamic load of the rated sliced rolling elements of the inner ring in raceway B, q Bc,o is the dynamic load of the rated sliced rolling elements of the outer ring in raceway B, q Ae,i,k is the equivalent dynamic load of the kth slice of the inner ring in raceway A, q Ae,o,k is the equivalent dynamic load of the kth slice of the outer ring in raceway A, q Be,i,k is the equivalent dynamic load of the kth slice of the inner ring in raceway B, q Be,o,k is the equivalent dynamic load of the kth slice of the outer ring in raceway B, m A is the number of slices of the rolling elements in raceway A along the radial direction of the roller, m B is the number of slices of the rolling elements in raceway B along the radial direction of the roller.

Images