Shaping method of tapered roller bearing

Abstract

The invention relates to the technical field of bearing modification, in particular to a tapered roller bearing modification method, which comprises the following steps of: establishing a tapered roller bearing model, and loading an actual stress working condition of a bearing; convexity values are selected at equal intervals, and comprehensive stress concentration coefficients Kt matched with different convexity values of the bearing outer ring, the bearing inner ring and the rolling body are calculated; respectively drawing relation curves of convexity values of the inner ring, the outer ring and the rolling body and Kt; selecting the convexity value optimization range of the outer ring, the inner ring and the rolling body corresponding to the minimum value of the Kt, and calculating the optimal convexity modification parameters of the outer ring, the inner ring and the rolling body by taking the minimum value of the Kt as an optimization target and adopting a curved surface response method; and modifying the tapered roller bearing by using the convexity modification parameters. According to the method, the possibility that stress concentration occurs between two parts of a bearing inner ring and an outer ring and a rolling body is considered at the same time, weights are given for calculation, a bearing mechanical analysis model is established, and a better convexity modification value range of the outer ring, the inner ring and the rolling body is obtained, so that the final modification effect of the bearing is optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of bearing profiling, and particularly to a profiling method for tapered roller bearings. Background Art

[0002] The conventional profiling methods for tapered roller bearings are rolling element convexity profiling or profiling at both ends. Due to the cost considerations of the main engine factory and the compression of the installation space, the performance requirements for the bearing, such as load-carrying capacity and life, are gradually increasing. Only profiling the rolling elements no longer meets the anti-fatigue requirements of the bearing. Summary of the Invention

[0003] In view of the defects of the prior art, the present invention provides a profiling method for tapered roller bearings. Aiming at the bearing operating conditions, considering the possibility of stress concentration between the two parts of the inner ring and the outer ring of the bearing and the rolling elements, and assigning weights for calculation, a bearing mechanical analysis model is established to obtain the optimal value ranges of the convexity profiling of the outer ring, inner ring, and rolling elements of the bearing, so as to optimize the final profiling effect of the bearing.

[0004] To achieve the above object, the technical solution provided by the present invention is a profiling method for tapered roller bearings, and its specific steps include: Establish a tapered roller bearing model and load the actual force conditions of the bearing; Select convexity values at equal intervals and calculate the comprehensive stress concentration coefficient Kt matching different convexity values of the outer ring, inner ring, and rolling elements of the bearing; Respectively plot the relationship curves between the inner ring convexity value and Kt, the outer ring convexity value and Kt, and the rolling element convexity value and Kt; Select the optimized range of the outer ring convexity value, the optimized range of the inner ring convexity value, and the optimized range of the rolling element convexity value corresponding to the minimum value of Kt, Taking the minimum value of Kt as the optimization goal, use the surface response method to calculate the optimal convexity profiling parameters of the outer ring, inner ring, and rolling elements; Use the convexity profiling parameters to profile the tapered roller bearing.

[0005] Further, the profiling method further includes calculating the profiling radii of the outer ring, inner ring, and rolling elements of the tapered roller bearing under different convexity values respectively, and the calculation formula: R = [L 2 / (8 × △C)] + 0.5 × △C, wherein, R is the profiling radius, L is the effective length, and △C is the convexity value.

[0006] Further, the step of selecting convexity values at equal intervals and calculating the comprehensive stress concentration coefficient Kt matching different convexity values of the outer ring, inner ring, and rolling elements of the bearing includes: The convexity values are selected at equal intervals, and the comprehensive stress concentration coefficient Kt corresponding to different convexity value matches of the outer ring, inner ring, and rolling elements of the bearing is calculated. The calculation formula is: Kt = A × k o + B × k i , where, k o is the stress concentration coefficient of the outer raceway, and k i is the stress concentration coefficient of the inner raceway, and A and B satisfy: A + B = 1; A / B = M / N; M is the average contact stress between the rolling element with the largest force and the outer raceway of the non-modified structure; N is the average contact stress between the rolling element with the largest force and the inner raceway of the non-modified structure; k o is the ratio of the maximum contact stress of the outer raceway to the average contact stress of the outer raceway; k i is the ratio of the maximum contact stress of the inner raceway to the average contact stress of the inner raceway.

[0007] Furthermore, without modifying the outer raceway, inner raceway, and rolling elements of the bearing, the calculation results of the bearing contact stress for the non-modified type are obtained; According to the calculation results, the maximum contact stress value of the outer raceway of the rolling element with the largest force is obtained, the angular position where the rolling element is most stressed in the circumferential direction is located, and the contact stress distribution values along the generatrix of the rolling element at this angular position are obtained. The average of these values is the average contact stress M between the rolling element with the largest force and the outer raceway of the non-modified structure; According to the calculation results, the maximum contact stress value of the inner raceway of the rolling element with the largest force is obtained, the angular position where the rolling element is most stressed in the circumferential direction is located, and the contact stress distribution values along the generatrix of the rolling element at this angular position are obtained. The average of these values is the average contact stress N between the rolling element with the largest force and the inner raceway of the non-modified structure.

[0008] Furthermore, a set of convexity values is selected to modify the outer and inner raceways and rolling elements of the bearing, and the calculation results of the contact stress for the modified bearing are obtained; According to the calculation results, the maximum contact stress value of the outer raceway of the rolling element with the largest force is obtained, the angular position where the rolling element is most stressed in the circumferential direction is located, and the contact stress distribution values along the generatrix of the rolling element at this angular position are obtained. The average of these values is the average contact stress of the outer raceway; then, dividing the maximum contact stress value of the outer raceway by the average contact stress of the outer raceway can obtain k o ; According to the calculation results, obtain the maximum inner raceway contact stress value of the rolling element with the maximum force, locate the angular position where the force on the rolling element in the circumferential direction is the largest, and obtain the contact stress distribution value along the generatrix of the rolling element at this angular position. The average of these values is the average contact stress of the inner raceway; then divide the maximum contact stress value of the inner raceway by the average contact stress of the inner raceway to obtain k i 。

[0009] Further, the step of selecting the optimized range of the outer ring convexity value, the optimized range of the inner ring convexity value, and the optimized range of the rolling element convexity value corresponding to the minimum value of Kt includes: Select the outer ring convexity value △C corresponding to the minimum value of Kt o1 、the inner ring convexity value △C i1 and the rolling element convexity value △C1; Calculate the absolute value of the difference between the outer ring convexity value △C o1 and other outer ring convexity values △C o , and select two outer ring convexity values △C with smaller absolute values o as the convexity values △C o2 and △C o3 ; Calculate the absolute value of the difference between the inner ring convexity value △C i1 and other inner ring convexity values △C i , and select two inner ring convexity values △C with smaller absolute values i as the convexity values △C i2 and △C i3 ; Calculate the absolute value of the difference between the rolling element convexity value △C1 and other rolling element convexity values △C, and select two rolling element convexity values △C with smaller absolute values as the convexity values △C2 and △C3; Combine the 9 convexity values of △C o1 , △C o2 , △C o3 , △C i1 , △C i2 , △C i3 , △C1, △C2 and △C3 into 27 groups of convexity value combinations, and obtain the Kt corresponding to the 27 groups of convexity value combinations respectively.

[0010] Further, the tapered roller bearing model is established using Romax simulation software.

[0011] Further, the tapered roller bearing model uses a stiffness bearing to cooperate in establishing the shafting.

[0012] Advantages of the present invention: For the working conditions of bearings, the possibility of stress concentration occurring between the two parts of the inner ring and outer ring of the bearing and the rolling elements is considered simultaneously, and weights are assigned for calculation, which can be used as an index for scientifically quantifying and evaluating the anti-fatigue characteristics of bearings; considering factors such as processing cost and processing feasibility, a bearing mechanical analysis model is established to obtain the optimal value range of the convexity modification of the outer ring, inner ring, and rolling elements of the bearing. Taking the proposed comprehensive stress concentration coefficient as the optimization target, the optimal solution of the three-convex modification is obtained by using the surface response method. Description of the Drawings

[0013] Figure 1 It is a schematic structural diagram of a tapered roller bearing in an embodiment of the present invention; Figure 2 It is a schematic structural diagram of the outer ring of a tapered roller bearing in an embodiment of the present invention; Figure 3 It is a schematic structural diagram of the inner ring of a tapered roller bearing in an embodiment of the present invention; Figure 4 It is a schematic structural diagram of the rolling element of a tapered roller bearing in an embodiment of the present invention; Figure 5 It is a model established by using Romax in a method for modifying the profile of a tapered roller bearing in an embodiment of the present invention; Figure 6 It is a curve of the comprehensive stress concentration coefficient Kt varying with the outer ring convexity value in a method for modifying the profile of a tapered roller bearing in an embodiment of the present invention; Figure 7 It is a curve of the comprehensive stress concentration coefficient Kt varying with the inner ring convexity value in a method for modifying the profile of a tapered roller bearing in an embodiment of the present invention; Figure 8 It is a curve of the comprehensive stress concentration coefficient Kt varying with the rolling element convexity value in a method for modifying the profile of a tapered roller bearing in an embodiment of the present invention; In the figure: 1. Outer ring, 2. Cage, 3. Inner ring, 4. Rolling element. Detailed Embodiments

[0014] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following detailed description of the specific embodiments of the present invention will be made in conjunction with the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0015] See Figure 1, showing a schematic structural diagram of a tapered roller bearing in an embodiment of the present invention, specifically the 32028 bearing, which is a single-row tapered roller bearing (type 32000) with the brand of ZWZ bearing. The tapered roller bearing includes an outer ring 1, a cage 2, an inner ring 3, and rolling elements 4. The specific steps of the modification method for the tapered roller bearing in this embodiment include: Step S100, as Figure 5 shown, use Romax to establish a tapered roller bearing model and load the actual force conditions of the bearing; establish a shafting with a stiffness bearing fit to avoid interference from other bearings to the analyzed bearing; Step S200, refer to Figures 2 - 4 , calculate the modification radii of the outer ring, inner ring, and rolling elements of the tapered roller bearing under different convexity values respectively. The calculation formula is: R = [L 2 / (8×△C)] + 0.5×△C, where R is the modification radius, L is the effective length, and △C is the convexity value; calculate the modification radii of the outer ring, inner ring, and rolling elements of the tapered roller bearing under different convexity values. The modification radius is used as the input value for calculating the contact stress in the Romax software. After modifying the tapered roller bearing model established in Step S100 using the calculated modification radius and performing stress analysis by simulating the actual force conditions of the bearing, the stress value is further obtained. Figure 4 In

[0016] r is the nominal dimension of the rolling element chamfer. When calculating the effective length of the rolling element using the formula, the effective length L in the formula is equal to the full length of the rolling element minus twice the nominal dimension of the rolling element chamfer. Figures 6 - 8 Step S300, refer to Kt = A×k o + B×k i , where, k o is the stress concentration coefficient of the outer raceway, k i is the stress concentration coefficient of the inner raceway, and A and B satisfy: A + B = 1; A / B = M / N; M is the average contact stress between the rolling element with the maximum force in the non-modified structure and the outer raceway; N is the average contact stress between the rolling element with the maximum force in the non-modified structure and the inner raceway; Specifically, in one embodiment, in step S100, a tapered roller bearing model is established using Romax software, and the actual load-bearing condition is simulated. In step S300, the outer raceway, inner raceway, and rolling elements of the bearing are not profiled, and the contact stress calculation results of the unprofiled bearing are obtained. According to the calculation results, the maximum outer and inner raceway contact stress values of the rolling element with the greatest force are obtained, the angular position with the greatest circumferential force on the rolling element is located, and the contact stress distribution values along the generatrix of the rolling element at this angular position are obtained. The average of these values is the average contact stress between the rolling element with the greatest force in the unprofiled structure and the outer and inner raceways. It should be noted that the average contact stress between the rolling element with the greatest force in the unprofiled structure and the outer raceway refers to the average contact stress between the unprofiled rolling element and the unprofiled outer raceway; similarly, the average contact stress between the rolling element with the greatest force in the unprofiled structure and the inner raceway refers to the average contact stress between the unprofiled rolling element and the unprofiled inner raceway.

[0017] k o is the ratio of the maximum contact stress of the outer raceway to the average contact stress of the outer raceway; k i is the ratio of the maximum contact stress of the inner raceway to the average contact stress of the inner raceway; Specifically, in one embodiment, a tapered roller bearing model is established using Romax software, and the actual load-bearing condition is simulated. A set of convexity values is selected to profile the outer and inner raceways and the rolling elements of the bearing, and the contact stress calculation results of the profiled bearing are obtained. According to the calculation results, the maximum outer raceway contact stress value of the rolling element with the greatest force is obtained, the angular position with the greatest circumferential force on the rolling element is located, and the contact stress distribution values along the generatrix of the rolling element at this angular position are obtained. The average of these values is the average contact stress of the outer raceway. Then, dividing the maximum outer raceway contact stress value by the average contact stress of the outer raceway gives k o ; In addition, according to the calculation results, the maximum inner raceway contact stress value of the rolling element with the greatest force is obtained, the angular position with the greatest circumferential force on the rolling element is located, and the contact stress distribution values along the generatrix of the rolling element at this angular position are obtained. The average of these values is the average contact stress of the inner raceway. Then, dividing the maximum inner raceway contact stress value by the average contact stress of the inner raceway gives k i .

[0018] In step S400, the curves of the inner ring convexity value versus Kt, the outer ring convexity value versus Kt, and the rolling element convexity value versus Kt are respectively plotted; See Figure 6 , and select the outer ring convexity value of 40 um corresponding to the minimum value of Kt; in addition, select two convexity values of 30 um and 35 um with relatively small absolute differences from the outer ring convexity value of 40 um among other outer ring convexity values.

[0019] SeeFigure 7 Select the inner ring convexity value of 20 um corresponding to the minimum value of Kt; in addition, select two convexity values of 15 um and 25 um with relatively small absolute values of the difference from the inner ring convexity value of 20 um among other inner ring convexity values.

[0020] See Figure 8 Select the convexity value of the rolling element of 40 um corresponding to the minimum value of Kt; in addition, select two convexity values of 30 um and 35 um with relatively small absolute values of the difference from the convexity value of the rolling element of 40 um among other convexity values of the rolling element.

[0021] It should be noted that when taking values, take two relatively adjacent values. Specifically, when the convexity value corresponding to the minimum value of Kt is already the maximum value, take the two values before it; when the convexity value corresponding to the minimum value of Kt is not the maximum value, take the two values before and after it respectively.

[0022] Step S500, according to Figures 6 - 8 It can be seen that considering the optimal range of the comprehensive stress concentration coefficient Kt, the optimized range of the outer ring convexity value is 30 um to 40 um, the optimized range of the rolling element convexity value is 30 um to 40 um, and the optimized range of the inner ring convexity value is 15 um to 25 um. See Table 1: The design response table of the three variables, where -1 represents the minimum value of the convexity value optimization range, 0 represents the intermediate value of the convexity value optimization range, and 1 represents the maximum value of the convexity value optimization range. Taking the rolling element as an example, the optimized range of the rolling element convexity value is 30 um to 40 um. In the response table, -1 refers to 30 um, 0 refers to 35 um, and 1 refers to 40 um.

[0023] Table 1

[0024] According to Table 1, using the surface response method, the convexity values of the outer ring, inner ring, and rolling element corresponding to the optimal solution of Kt can be calculated. The outer ring convexity value is 32.26 um, the inner ring convexity value is 19.64 um, and the rolling element convexity value is 35.67 um.

[0025] Step S600, use the convexity modification parameters, with the outer ring convexity value of 32.26 um, the inner ring convexity value of 19.64 um, and the rolling element convexity value of 35.67 um to modify the tapered roller bearing.

[0026] Traditional empirical formula for full convex modification of rolling elements:

[0027] Where: △C is the convexity value, with the unit of mm; L is the effective length, with the unit of mm; E 1.E 2 is the elastic modulus of the material, with the unit of N / mm 2 ; for steel bearings ; v 1. v 2 is the Poisson's ratio of the material. For steel bearings ; Q is the load of the rolling element with the maximum load in the bearing, with the unit of N.

[0028] The convexity of the outer and inner raceways follows the factory processing standard. Generally, the convexity is controlled at 3 - 7 μm.

[0029] Table 2

[0030] See Table 2: Comparison table of the comprehensive stress concentration coefficient Kt of the optimized bearing and the Kt of the traditional empirical three - convex profile - modified bearing. The comprehensive stress concentration coefficient Kt of the optimized bearing has decreased by 19.58% compared with the traditional empirical three - convex profile - modified structure. The problem of bearing raceway fatigue has been effectively improved and verified by the bearing enhanced life test. The research results have effectively improved the empirical - based three - convex profile - modification method of bearings and have important engineering application value.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0032] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0033] In the present invention, unless otherwise clearly specified or defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified or defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0035] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

Claims

1. A modification method for a tapered roller bearing, characterized in that: The specific steps include: Establish a tapered roller bearing model and load the actual force conditions of the bearing; Select the convexity values at equal intervals and calculate the comprehensive stress concentration coefficient Kt for different convexity value matches of the outer ring, inner ring, and rolling elements of the bearing; Respectively plot the relationship curves of the inner ring convexity value and Kt, the outer ring convexity value and Kt, and the rolling element convexity value and Kt; Select the optimization ranges of the outer ring convexity value, inner ring convexity value, and rolling element convexity value corresponding to the minimum value of Kt, Taking the minimum value of Kt as the optimization goal, use the surface response method to calculate the optimal convexity modification parameters of the outer ring, inner ring, and rolling elements; Modify the tapered roller bearing using the convexity modification parameters.

2. The profiling method of a tapered roller bearing according to claim 1, characterized in that: The modification method also includes calculating the modification radii of the outer ring, inner ring, and rolling elements of the tapered roller bearing under different convexity values respectively. The calculation formula: R = [L 2 / (8 × △C)] + 0.5 × △C, Where, R is the modification radius, L is the effective length, and △C is the convexity value.

3. A profiling method for a tapered roller bearing according to claim 1, characterized in that: The steps of selecting the convexity values at equal intervals and calculating the comprehensive stress concentration coefficient Kt for different convexity value matches of the outer ring, inner ring, and rolling elements of the bearing include: Select the convexity values at equal intervals and calculate the comprehensive stress concentration coefficient Kt for different convexity value matches of the outer ring, inner ring, and rolling elements of the bearing. The calculation formula: Kt = A × k o + B × k i , Where, k o is the stress concentration coefficient of the outer raceway, k i is the stress concentration coefficient of the inner raceway, and A and B satisfy: A + B = 1; A / B = M / N; M is the average contact stress between the most stressed rolling element and the outer raceway in the non-modified structure; N is the average contact stress between the most stressed rolling element and the inner raceway in the non-modified structure.

4. A profiling method for a tapered roller bearing according to claim 3, characterized in that: Do not modify the outer raceway, inner raceway, and rolling elements of the bearing to obtain the calculation results of the bearing contact stress without modification; According to the calculation results, obtain the maximum outer raceway contact stress value of the most stressed rolling element, locate the angular position where the rolling element is most stressed in the circumferential direction, and obtain the contact stress distribution values along the generatrix of the rolling element at this angular position. The average of these values is the average contact stress M between the most stressed rolling element and the outer raceway in the non-modified structure; According to the calculation results, obtain the maximum inner raceway contact stress value of the most stressed rolling element, locate the angular position where the rolling element is most stressed in the circumferential direction, and obtain the contact stress distribution values along the generatrix of the rolling element at this angular position. The average of these values is the average contact stress N between the most stressed rolling element and the inner raceway in the non-modified structure.

5. A profiling method for a tapered roller bearing according to claim 3, characterized in that: Select a set of convexity values to modify the outer and inner raceways and rolling elements of the bearing to obtain the calculation results of the contact stress of the modified bearing; According to the calculation results, obtain the maximum outer raceway contact stress value of the rolling element with the largest force, locate the angular position where the force on the rolling element in the circumferential direction is the largest, and obtain the contact stress distribution value along the generatrix of the rolling element at this angular position. The average of these values is the average contact stress of the outer raceway; then divide the maximum contact stress value of the outer raceway by the average contact stress of the outer raceway to obtain k o ; According to the calculation results, the maximum inner raceway contact stress value of the rolling element with the maximum force is obtained, the angular position where the force on the rolling element in the circumferential direction is the largest is located, and the contact stress distribution value along the generatrix of the rolling element at this angular position is obtained. The average of these values is the average contact stress of the inner raceway; then dividing the maximum contact stress value of the inner raceway by the average contact stress of the inner raceway can obtain k i 。 6. A profiling method for a tapered roller bearing according to claim 1, characterized in that: The steps of selecting the optimization ranges of the outer ring convexity value, inner ring convexity value, and rolling element convexity value corresponding to the minimum value of Kt include: Select the outer ring convexity value △C corresponding to the minimum value of Kt o1 , inner ring convexity value △C i1 and rolling element convexity value △C1; Calculate the outer ring convexity value △C o1 The absolute value of the difference from other outer ring convexity values △C o Select the two outer ring convexity values △C with smaller absolute values o As the convexity value △C o2 And △C o3 ; Calculate the inner ring convexity value △C i1 The absolute value of the difference from other inner ring convexity values △C i Select the two inner ring convexity values △C with smaller absolute values i As the convexity value △C i2 And △C i3 ; Calculate the absolute value of the difference between the rolling element convexity value △C1 and the other rolling element convexity values △C, and select the two rolling element convexity values △C with smaller absolute values as the convexity values △C2 and △C3; △C o1 、△C o2 、△C o3 、△C i1 、△C i2 、△C i3 、 △C1, △C2 and △C3 are combined into 27 groups of camber value combinations, and the corresponding Kt values for the 27 groups of camber value combinations are obtained respectively.

7. A profiling method for a tapered roller bearing according to any one of claims 1-6, characterized in that: The tapered roller bearing model is established using Romax simulation software.

8. A method for modifying a tapered roller bearing according to any one of claims 1-6, characterized in that: The tapered roller bearing model uses a stiffness bearing to cooperate in establishing the shafting.

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