Finite element dynamics simulation analysis method for bearing inner ring creep influence factors

Abstract

The invention relates to a finite element dynamics simulation analysis method for bearing inner ring creep influence factors, and belongs to the technical field of mechanical engineering. The method comprises the following steps: establishing a deep groove ball bearing-stepped shaft finite element dynamic model by using three-dimensional modeling software; obtaining the contact pressure of the interference fit surface of the bearing inner ring and the shaft through finite element analysis, and comparing the contact pressure with an analytic solution of the Lame equation to verify the accuracy of the deep groove ball bearing-stepped shaft finite element kinetic model; and analyzing an influence rule of the magnitude of interference, the radial load and the pre-tightening force on the creep deformation of the bearing inner ring by utilizing finite element transient dynamics. Compared with the prior art, the method has the advantages that the influence rule of different interference magnitudes, radial loads and pretightening forces on the creep of the bearing inner ring is researched, measures for improving the creep resistance of the bearing inner ring are provided according to the influence rule, the defects of an experimental method are overcome, and the method has guidance and reference significance for improving the creep resistance of the bearing in engineering practice.

Description

Technical Field

[0001] The present invention relates to a finite element dynamics simulation analysis method for influencing factors of inner ring creep of a bearing, belonging to the technical field of mechanical engineering. Background Art

[0002] As an indispensable key component in mechanical equipment, the rolling bearing is not only a basic component for supporting the transmission system, but also a key hub determining mechanical efficiency and reliability. The inner ring of the bearing is fixed to the shaft by interference fit to prevent the inner ring from sliding relative to the shaft. However, once the appropriate interference amount cannot be maintained, a gap is generated on the mating surface between the inner ring and the shaft, and the inner ring will slide relative to the shaft. This phenomenon is called inner ring creep. This seemingly small deformation, if accumulated over a long time, will cause the mating surface to loosen and the stress distribution to change, thereby leading to increased bearing vibration, abnormal temperature rise, and even bearing failure, seriously threatening the safe and stable operation of the equipment. Therefore, how to improve the anti-creep ability of the bearing has important practical application significance for improving the operation efficiency, service life, etc. of mechanical equipment.

[0003] At present, the research methods for rolling bearings, especially for inner ring creep of bearings, are mainly experiments, and the influencing factors for inner ring creep of bearings mainly studied are the interference amount. When the bearing model, working conditions, etc. change, the experiment needs to be carried out again, consuming a large amount of financial and human resources.

[0004] With the development of computer-aided engineering, finite element analysis has been widely used in the mechanical field. It has become possible to simulate the inner ring creep of the bearing by using the finite element numerical simulation method, and the method based on finite element numerical simulation can effectively make up for the deficiencies of the inner ring creep experiment of the bearing. Therefore, how to obtain the influence laws of different parameters on the inner ring creep of the bearing under multiple working conditions by using the finite element numerical simulation method is one of the important research directions at present. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to provide a finite element dynamics simulation analysis method for influencing factors of inner ring creep of a bearing, to study and solve the influence laws of different interference amounts, radial loads, and preloading forces on the inner ring creep of the bearing, and to propose measures for improving the anti-creep performance of the inner ring of the bearing according to the above influence laws, making up for the deficiencies of the experimental method, and having guiding and reference significance for improving the anti-creep performance of the bearing in engineering practice.

[0006] The technical solution adopted by the present invention is: a finite element dynamics simulation analysis method for influencing factors of inner ring creep of a bearing, including the following steps:

[0007] Step S1: Establish a finite element dynamics model of a deep groove ball bearing - stepped shaft;

[0008] Step S2: Obtain the contact pressure of the interference fit surface between the bearing inner ring and the shaft through finite element analysis and compare it with the analytical solution of the Lame equation to verify the accuracy of the finite element dynamics model of the deep groove ball bearing - stepped shaft;

[0009] Step S3: Conduct transient dynamics simulation analysis on the finite element dynamics model of the deep groove ball bearing - stepped shaft to obtain the influence law of different parameters on the creep of the bearing inner ring;

[0010] Step S4: Give measures to improve the anti - creep performance of the bearing in engineering practice according to the results of the dynamics simulation.

[0011] Specifically, the step S1 specifically includes:

[0012] S1 - 1: Establish a finite element dynamics model of the deep groove ball bearing - stepped shaft using 3D modeling software;

[0013] S1 - 2: Based on the established finite element dynamics model of the deep groove ball bearing - stepped shaft, use the finite element pre - processing software Hypermesh for mesh division; the number of elements for mesh division is 222256, and the number of nodes is 261420.

[0014] S1 - 3: Define the simulation material parameters, boundary conditions, and load conditions.

[0015] Specifically, the step S2 specifically includes:

[0016] S2 - 1: Conduct simulation analysis on the finite element dynamics model of the deep groove ball bearing - stepped shaft to obtain the contact pressure of the fit surface between the bearing inner ring and the shaft. Since the analytical method cannot consider the situation at the contact edge, the contact pressure in the middle area of the fit surface is selected here for comparison with the analytical solution of the Lame equation. Select the finite element nodes with an axial relative position of 6 - 12 mm for solution, and take the average to obtain the contact pressure P ave As expressed by the following formula:

[0017]

[0018] In the formula: P ave is the average contact pressure of the contact surface; p i is the contact pressure at the node obtained from the finite element simulation, n is the number of nodes, and i is a variable.

[0019] S2 - 2: Calculate the theoretical analytical solution of the contact pressure of the fit surface between the inner ring and the shaft through the Lame equation. The Lame equation gives the relationship between the contact pressure of the interference fit surface and the interference amount:

[0020]

[0021] Where: p is the contact pressure of the interference fit surface; E is the elastic modulus of the material; δ is the interference amount; c is the radius of the inner ring raceway surface; b is the radius of the shaft.

[0022] Specifically, step S3 specifically includes:

[0023] S3-1: Perform transient dynamic finite element simulation analysis on the mating surface of the bearing inner ring and the shaft with different interference amounts, and obtain the magnitude of the slip amount of the bearing inner ring relative to the shaft under different interference amounts;

[0024] S3-2: Perform transient dynamic finite element simulation analysis on the inner surface of the bearing inner ring with different radial loads, and obtain the magnitude of the slip amount of the bearing inner ring relative to the shaft under different radial loads;

[0025] S3-3: Perform transient dynamic finite element simulation analysis on the bearing with different preloading forces, and obtain the magnitude of the slip amount of the bearing inner ring relative to the shaft under different preloading forces.

[0026] Specifically, step S4 specifically includes:

[0027] S4-1: Fit the slip amount results obtained by transient dynamic simulation according to different interference amounts, different radial loads, and different preloading forces in S3-1 to S3-3 into curves;

[0028] S4-2: Give measures to improve the anti-creep performance of the bearing inner ring by analyzing the curves fitted in S4-1.

[0029] The beneficial effects of the present invention are as follows: The present invention conducts dynamic finite element numerical simulation analysis on the influencing factors of the creep of the deep groove ball bearing inner ring, and gives measures to improve the anti-creep performance of the bearing inner ring through the numerical simulation results. This method can effectively reflect the phenomenon of the creep of the bearing inner ring, effectively make up for the deficiencies of traditional experimental methods, and can provide certain reference and guidance in engineering practice. Description of the Drawings

[0030] Figure 1 is the flow schematic diagram of the present invention;

[0031] Figure 2 is the comparison diagram of the contact pressure between the shaft and the inner ring nodes under different interference amounts of the present invention;

[0032] Figure 3 is the comparison diagram of the contact pressure between the shaft and the inner ring nodes under different radial loads of the present invention;

[0033] Figure 4 is the comparison diagram of the contact pressure between the shaft and the inner ring nodes under different preloading forces of the present invention;

[0034] Figure 5 is the comparison diagram of the slip amount of the bearing inner ring relative to the shaft under different interference amounts of the present invention;

[0035] Figure 6 It is a comparison diagram of the relative slip amount of the bearing inner ring with respect to the shaft under different radial loads of the present invention;

[0036] Figure 7 It is a comparison diagram of the relative slip amount of the bearing inner ring with respect to the shaft under different preloading forces of the present invention. Detailed implementation manners

[0037] To better understand the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, the content of the present invention is not limited to the following embodiments only.

[0038] Embodiment 1: As Figure 1-7 shown, a finite element dynamics simulation analysis method for influencing factors of bearing inner ring creep includes the following steps:

[0039] Step S1: Establish a finite element dynamics model of a deep groove ball bearing - stepped shaft. In this embodiment, the model number of the selected deep groove ball bearing is 6208;

[0040] Step S2: Obtain the contact pressure of the interference fit surface between the bearing inner ring and the shaft through finite element analysis and compare it with the analytical solution of the Lame equation to verify the accuracy of the finite element dynamics model of the deep groove ball bearing - stepped shaft;

[0041] Step S3: Conduct transient dynamics simulation analysis on the finite element dynamics model of the deep groove ball bearing - stepped shaft to obtain the influence law of different parameters on the creep of the bearing inner ring;

[0042] Step S4: Give measures to improve the anti - creep performance of the bearing in engineering practice according to the dynamics simulation results.

[0043] Further, the said step 1) includes the following steps:

[0044] S1 - 1: Use the three - dimensional modeling software Solidworks to establish a finite element dynamics model of a deep groove ball bearing - stepped shaft;

[0045] S1 - 2: On the basis of the established finite element dynamics model of the deep groove ball bearing - stepped shaft, import the finite element dynamics model of the deep groove ball bearing - stepped shaft into the finite element pre - processing software Hypermesh for mesh division. Mesh refinement is carried out on the contact areas between the balls and the inner and outer ring raceways, and the contact parts such as the bearing inner ring and the shaft. Finally, the number of elements for mesh division is 222256, and the number of nodes is 261420;

[0046] S1-3: Define the simulation material parameters, boundary conditions, and load conditions. When establishing the finite element dynamic model of the deep groove ball bearing - stepped shaft, corresponding boundary conditions need to be established according to the actual working conditions of the bearing. Set the contact mode between the ball and the inner and outer ring raceways as frictional contact with a friction coefficient of 0.1; the contact mode between the shaft and the inner ring of the bearing is frictional contact with a friction coefficient of 0.1; the contact mode between the ball and the cage is frictionless contact, with a total of 29 pairs of contact pairs. Adjust the interference amount between the shaft and the inner ring by modifying the "offset" in the contact settings; apply a fixed constraint to the outer surface of the bearing outer ring to restrict its degrees of freedom in three different directions of X, Y, and Z to simulate the restriction of the bearing seat on the bearing in the actual situation; apply a radial bearing load to the inner surface of the bearing inner ring, apply a rotational pair to the shaft, and apply a rotational speed.

[0047] Further, step 2) includes the following steps:

[0048] S2-1: The contact pressure on the interference fit surface between the inner ring of the bearing and the shaft is an important factor affecting the creep of the inner ring. Perform a simulation analysis on the finite element dynamic model of the deep groove ball bearing - stepped shaft to obtain the contact pressure on the mating surface between the inner ring of the bearing and the shaft; since the analytical method cannot consider the situation at the contact edge, the contact pressure in the middle area of the mating surface is selected here for comparison with the analytical solution of the Lame equation; as Figure 2 shown: Obtain the contact pressure of the nodes on the mating surface between the inner ring of the bearing and the shaft under interference amounts of 0.01mm, 0.02mm, and 0.03mm respectively; select the finite element nodes with an axial relative position of 6 - 12mm for solution, and take the average to obtain the contact pressure P ave as expressed by the following formula:

[0049]

[0050] In the formula: P ave is the average contact pressure of the contact surface; p i is the contact pressure on the node obtained from the finite element simulation, n is the number of nodes, and i is the variable.

[0051] S2-2: Calculate the theoretical analytical solution of the contact pressure on the mating surface between the inner ring and the shaft through the Lame equation. The Lame equation gives the relationship between the contact pressure on the interference fit surface and the interference amount:

[0052]

[0053] In the formula: p is the contact pressure on the interference fit surface; E is the elastic modulus of the material; δ is the interference amount; c is the radius of the inner ring raceway surface; b is the radius of the shaft.

[0054] As shown in Table 1: By comparing the numerical simulation solution of the contact pressure with the analytical solution of the Lame equation, the relative error is within 3%, verifying the accuracy of the finite element dynamic model of the deep groove ball bearing - stepped shaft.

[0055] Table 1

[0056]

[0057] The contact pressure on the mating surface under different radial loads is obtained through numerical simulation, as Figure 3 shown: the radial load has little effect on the contact pressure of the mating surface; the contact pressure between the inner ring of the bearing and the shaft mating surface under different preloading forces is obtained, as Figure 4 shown: the influence of the preloading force on the contact pressure is mainly reflected on the contact edge of the mating surface; with the application of the preloading force, the contact pressure at the contact edge shows a decreasing trend, and the pressure distribution on the contact surface becomes more uniform, alleviating the stress concentration at the contact edge. Therefore, applying a preloading force can reduce the fatigue and wear at the contact edge.

[0058] Further, step 3) includes the following steps:

[0059] S3-1: When the radial load of the bearing is 10 KN, the rotational speed is 600 rpm, and the calculation time is 0.1 s, the slip amounts of the inner ring of the bearing relative to the shaft under interference amounts of 0.01 mm, 0.02 mm, and 0.03 mm are obtained. The results show that: with the increase of the interference amount, the slip amount of the inner ring of the bearing relative to the shaft shows a decreasing trend. This is because as the interference amount increases, the contact pressure between the shaft and the inner ring increases, and the combined action of this contact pressure and the friction coefficient forms a static friction force, which improves the anti-creep ability of the inner ring of the bearing.

[0060] S3-2: On the premise of applying a fixed interference amount of 0.03 mm to the mating surface of the inner ring of the bearing and the shaft, radial loads of 5 KN, 15 KN, and 20 KN are respectively applied to the inner surface of the inner ring of the bearing, the calculation time is 0.1 s, and transient dynamic finite element simulation analysis is performed on the above three working conditions to obtain the slip amounts of the inner ring of the bearing relative to the shaft under the three working conditions. The results show that: with the increase of the radial load, the slip amount of the inner ring of the bearing relative to the shaft continuously increases. This is because as the radial load increases, the contact deformation on the mating surface of the shaft and the inner ring continuously increases, and the gap generated in the opposite direction of the radial load also continuously increases, reducing the anti-creep ability of the inner ring of the bearing.

[0061] S3-3: On the premise of applying a fixed interference amount of 0.01 mm and a radial load of 10 KN to the mating surface of the inner ring of the bearing and the shaft, preloading forces of 0 N, 2 KN, and 4 KN are respectively applied to the bearing, the calculation time is 0.1 s, and transient dynamic finite element simulation analysis is performed on the above three working conditions to obtain the slip amounts of the inner ring of the bearing relative to the shaft under the three working conditions. The results show that: the slip amount at the contact edge of the mating surface decreases with the application of the preloading force. This is because the application of the preloading force alleviates the stress concentration at the contact edge.

[0062] Further, step 4) includes the following steps:

[0063] S4-1: Fit the slip amount results obtained from transient dynamic simulation under the above different working conditions into curves: Fit the slip amount data obtained from numerical simulation analysis under different interference amounts into curves. As Figure 5 shown: Before 0.03 s, the slip amounts under the three working conditions all start to increase slowly from 0 because the first 0.03 s is the loading process of the load and rotational speed. When the load and rotational speed reach constant values, the growth of the slip amount is relatively fast. Finally, the slip distance gradually tends to a steady state with the increase of time. When the interference amount increases from 0.01 mm to 0.03 mm, the slip amount decreases by about 72%. Fit the slip amount data obtained from numerical simulation analysis under different radial loads into curves. As Figure 6 shown: Before 0.03 s, the slip amounts under the three working conditions all start to increase slowly from 0 because the first 0.03 s is the loading process of the load and rotational speed. When the load and rotational speed reach constant values, the growth of the slip amount is relatively fast. Finally, the slip distance gradually tends to a steady state with the increase of time. The difference in slip amount is very small when the radial loads are 5 KN and 15 KN, while the slip amount increases significantly when the radial load increases to 20 KN. This is because when the radial load is 20 KN, it is close to the limit value of the rated dynamic load of the bearing, and the contact deformation on the mating surface increases, resulting in a significant increase in the slip amount. When the radial load increases from 15 KN to 20 KN, the slip amount increases by about 45%. Fit the slip amount data obtained from numerical simulation analysis under different pre-tightening forces into curves. As Figure 7 shown: Before 0.03 s, the slip amounts under the three working conditions all start to increase slowly from 0 because the first 0.03 s is the loading process of the load and rotational speed. When the load and rotational speed reach constant values, the growth of the slip amount is relatively fast. Finally, the slip distance gradually tends to a steady state with the increase of time. When the pre-tightening force increases from 0 to 4 KN, the slip amount decreases by about 14%.

[0064] S4-2: Give measures to improve the anti-creep performance of the bearing inner ring by analyzing the curves fitted in S4-1: In engineering practice, the optimal interference amount selected for the 6208 type bearing is between 0.02 mm and 0.03 mm. In engineering practice, the radial load for the 6208 type bearing should not exceed 15 KN, otherwise the phenomenon of creep of the bearing inner ring will be rapidly aggravated. In engineering practice, in order to improve the anti-creep performance of deep groove ball bearings, axial pre-tightening can be carried out on deep groove ball bearings, and axial pre-tightening can reduce the stress concentration at the contact edge.

[0065] The specific implementation manners of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above implementation manners, and various changes can be made without departing from the gist of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. A finite element dynamics simulation analysis method for the factors affecting the creep of the inner ring of a bearing, characterized in that: The following steps are involved: Step S1: establishing a deep groove ball bearing-step shaft finite element dynamics model; Step S2: The contact pressure between the inner ring of the bearing and the interference fit surface of the shaft is obtained by finite element analysis and compared with the analytical solution of the Lame equation to verify the accuracy of the finite element dynamic model of the deep groove ball bearing-stepped shaft; Step S3: performing transient dynamic simulation analysis on the deep groove ball bearing-step shaft finite element dynamic model to obtain the influence of different parameters on the creep of the bearing inner ring; Step S4: providing measures for improving the anti-creep performance of bearings in engineering practice according to the dynamic simulation results.

2. The finite element dynamics simulation analysis method for the creep influencing factors of the inner ring of a bearing according to claim 1, characterized in that: The step S1 specifically includes: S1-1: Use 3D modeling software to establish a finite element dynamic model of deep groove ball bearing-step shaft; S1-2: Based on the established deep groove ball bearing-step shaft finite element dynamics model, the finite element pre-processing software Hypermesh is used for meshing; S1-3: Define simulation material parameters, boundary conditions and load conditions.

3. The finite element dynamics simulation analysis method for the creep influencing factors of the inner ring of a bearing according to claim 1, characterized in that: The step S2 specifically includes: S2-1: Simulate and analyze the finite element dynamics model of deep groove ball bearing-step shaft to obtain the contact pressure between the inner ring of the bearing and the shaft mating surface. Select the contact pressure in the middle area of ​​the mating surface to compare with the analytical solution of the Lame equation, select the finite element nodes in the middle area with the axial relative position to solve, and take the average to obtain the contact pressure P ave It is expressed as follows: Where: P ave is the average contact pressure on the contact surface; p i is the contact pressure on the node obtained by finite element simulation, n is the number of nodes, and i is the variable; S2-2: The theoretical analytical solution for calculating the contact pressure between the inner ring and the shaft is calculated using the Lame equation. The Lame equation gives the relationship between the contact pressure of the interference fit surface and the interference amount: Where: p is the contact pressure of the interference fit surface; E is the elastic modulus of the material; δ is the interference; c is the radius of the inner ring raceway surface; b is the shaft radius.

4. The finite element dynamics simulation analysis method for the creep influencing factors of the inner ring of a bearing according to claim 1, characterized in that: The step S3 specifically includes: S3-1: Perform transient dynamic finite element simulation analysis on the matching surface between the inner ring of the bearing and the shaft with different interference amounts, and obtain the slip amount of the inner ring of the bearing relative to the shaft under different interference amounts; S3-2: Apply different radial loads to the inner surface of the bearing inner ring to perform transient dynamic finite element simulation analysis to obtain the slip amount of the bearing inner ring relative to the shaft under different radial loads; S3-3: Apply different preload forces to the bearing and perform transient dynamic finite element simulation analysis to obtain the amount of slip of the bearing inner ring relative to the shaft under different preload forces.

5. The finite element dynamics simulation analysis method for the creep influencing factors of the inner ring of a bearing according to claim 4, characterized in that: The step S4 specifically includes: S4-1: Fitting the slip results obtained from S3-1 to S3-3 into a curve; S4-2: By analyzing the fitted curve in S4-1, measures to improve the creep resistance of the inner ring of the bearing are given.

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