Analysis Method of Slewing Bearing Based on the Coupling of Rolling Element Entities and Nonlinear Springs

Abstract

The present application discloses an analysis method for a slewing bearing based on the coupling of rolling element entities and non-linear springs, comprising the following steps: Step S1: Obtain the loads applied to the slewing bearing and determine the position of the rolling element with the maximum load; Step S2: Establish an overall finite element model of the slewing bearing, wherein the rolling element at the position with the maximum load is modeled as a solid model, and the remaining rolling elements are equivalent to non-linear springs; Step S3: Apply external loads to the established finite element model of the slewing bearing and conduct simulation calculations; Step S4: Obtain the finite element calculation results and analyze the overall load distribution state and local stress distribution state of the slewing bearing. By modeling the rolling element at the position with the maximum load as a solid model and equivalenting the remaining rolling elements to non-linear springs, the present application can accurately and efficiently obtain the overall load distribution state and local stress distribution state of the slewing bearing through one simulation calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of bearings, and in particular, to an analysis method for a slewing bearing based on the coupling of rolling element entities and non-linear springs. Background Art

[0002] A slewing bearing is a large slewing bearing that can simultaneously bear axial force, radial force and overturning moment, and has functions such as supporting, rotating and transmitting. Its structure is compact and its performance is excellent, and it is widely used in engineering machinery structures such as roadheaders and ships. Due to the harsh working environment and complex operating conditions of the slewing bearing, it is necessary to ensure the safety and stability of its service process. Therefore, it is crucial to conduct a comprehensive load and stress state analysis on the slewing bearing during the design stage.

[0003] The numerical analysis method based on finite element is currently the main method for calculating complex structures. However, considering the large size of the slewing bearing, the large number of rolling elements, and the complex rolling element / raceway contact, if a solid model is directly established for calculation, the meshing process is very complex and involves a large number of meshes, which will lead to extremely large subsequent calculation workload, slow convergence speed, and even non-convergence phenomenon, wasting computing resources and unable to guarantee the accuracy of the calculation results.

[0004] Based on this, some scholars have tried to introduce non-linear trusses, non-linear springs, etc., and equivalent all rolling elements to the above structures, which can eliminate the process of meshing the rolling elements, reduce the number of model meshes, and simplify the calculation process on the premise of ensuring the accuracy of the calculation results, achieving certain effects. However, the current rolling element equivalent calculation methods are all used to analyze the overall load distribution of the slewing bearing. If it is necessary to deeply analyze the local stress distribution state of the rolling elements and raceways after loading, it is necessary to re-establish a local raceway / rolling element contact model, and the load loading method and raceway / rolling element contact method of the constructed local model have been simplified, so the calculation results are not sufficient to reflect the contact state of the raceway / rolling element in the overall model, resulting in certain deviations in the analysis results for local stresses.

[0005] Therefore, there is an urgent need in the art for a new modeling and analysis method for slewing bearings that can solve the above deviation problems. Summary of the Invention

[0006] The purpose of the present application is to provide an analysis method for a slewing bearing based on the coupling of rolling element entities and non-linear springs, so as to accurately and efficiently obtain the overall load of the slewing bearing and the stress distribution state at the local maximum load-bearing part. The technical solution of the present application is as follows:

[0007] An analysis method for a slewing bearing based on the coupling of rolling element entities and non-linear springs, wherein a plurality of rolling elements are arranged in the slewing bearing, and the method includes the following steps:

[0008] Step S1: Obtain the load on the slewing bearing and determine the position of the rolling element that bears the maximum load.

[0009] Step S2: Establish an overall finite element model of the slewing bearing. Among them, the rolling elements at the position with the maximum load are modeled as solid models, and the remaining rolling elements are equivalent to non-linear springs.

[0010] Step S3: Apply external loads to the established finite element model of the slewing bearing and carry out simulation calculations.

[0011] Step S4: Obtain the finite element calculation results and analyze the overall load distribution state and local stress distribution state of the slewing bearing.

[0012] In some specific embodiments, before the step S2), it is necessary to obtain the non-linear stiffness coefficient curve of the non-linear spring through finite element analysis or experimental methods, and determine the number of non-linear springs used to equivalent a single rolling element.

[0013] In some specific embodiments, the process of obtaining the non-linear stiffness coefficient curve and the number of the non-linear spring is as follows:

[0014] Establish a finite element contact model of the roller / raceway and a space rectangular coordinate system, and mesh the finite element contact model of the roller / raceway.

[0015] According to the actual working conditions, constrain or release the degrees of freedom of the raceway and the roller in the x-axis, y-axis, and z-axis directions respectively.

[0016] Apply loads to the raceway, simulate and analyze the deformation of the roller under different loads, and obtain the non-linear stiffness coefficient curve of the non-linear spring used to equivalent the roller.

[0017] According to the size and load-bearing characteristics of the slewing bearing, determine that the roller is equivalent to N equally spaced non-linear springs.

[0018] In some specific embodiments, the element type of the meshing is C3D8I element.

[0019] The technical solution provided by this application has at least the following beneficial effects:

[0020] 1. By equivalently processing some rolling elements with non-linear springs, this application method converts the deformation of some rolling elements into the deformation of the springs, greatly simplifies the meshing process of the rolling elements and reduces the number of model meshes, reduces the computational workload, and improves the computational efficiency. At the same time, the rolling elements at the position with the maximum load are modeled as solid models and refined meshing is carried out, improving the computational accuracy and ensuring the accuracy of the obtained local stress distribution state. That is, this application method realizes the enhancement of the model convergence while ensuring the accuracy of the simulation results.

[0021] 2. Through one simulation calculation, the present invention can simultaneously obtain the overall load distribution state of the slewing bearing and the local stress state at the rolling element with the maximum load, without separately establishing a local model of the raceway / rolling element to analyze the local stress state of the bearing, avoiding the errors generated in the modeling and simulation processes of the local model of the raceway / rolling element, and ensuring the accuracy of the results of the local stress distribution state of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a flowchart of the analysis method for the slewing bearing based on the coupling of the rolling element entity and the nonlinear spring provided by the embodiment of the present application;

[0024] Figure 2 It is an axial sectional view (only partially shown) of a three-row cylindrical roller slewing bearing applying the method of the present invention in the embodiment of the present application;

[0025] Figure 3 It is a finite element contact model diagram of the roller / raceway established in the embodiment of the present application;

[0026] Figure 4 It is a non-linear stiffness coefficient curve diagram of the non-linear spring used to equivalent the roller in the embodiment of the present application;

[0027] Figure 5 It is a simplified roller / raceway contact model diagram in the embodiment of the present application;

[0028] In the figure, 1. Inner ring, 2. First outer ring, 3. Second outer ring, 4. Main thrust roller, 5. Radial roller, 6. Auxiliary thrust roller, 7. Non-linear spring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To facilitate the understanding of the present application, the following will describe the technical solutions in the present application more comprehensively and meticulously in conjunction with the drawings of the specification and the preferred embodiments. However, the protection scope of the present application is not limited to the following specific embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the protection scope of the present application.

[0030] It should be specifically noted that when a component is described as having a "fixed, fixedly connected, connected or communicated" relationship with another component, it can be directly fixed, fixedly connected, connected or communicated to the other component, or indirectly fixed, fixedly connected, connected or communicated to the other component through other intermediate components.

[0031] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of this application.

[0032] Embodiment

[0033] See Figure 2 , the analysis object in this application is a typical three-row cylindrical roller turntable bearing. The turntable bearing includes an inner ring 1 arranged radially and an outer ring. The outer ring includes a first outer ring 2 and a second outer ring 3 arranged axially. Among them, the second outer ring 3 is arranged closer to the working surface (such as the cutter head) than the first outer ring 2. The first outer ring 2 and the second outer ring 3 are fixedly connected by bolts. During the working process, the outer ring is fixed as a whole while the inner ring 1 rotates.

[0034] Along the direction away from the working surface, a secondary thrust roller 6, a radial roller 5, and a main thrust roller 4 are sequentially arranged axially between the inner ring 1 and the outer ring. The main thrust roller 4 is located between the first outer ring 2 and the inner ring 1. The secondary thrust roller 6 is located between the second outer ring 3 and the inner ring 1. The radial roller 5 is located at the junction of the first outer ring 2 and the second outer ring 3. Each roller is cylindrical. The rolling axes of the main thrust roller 4 and the secondary thrust roller 6 are perpendicular to the central axis of the turntable bearing. The rolling axis of the radial roller 5 is parallel to the central axis of the turntable bearing.

[0035] See Figure 1 , a method for analyzing a turntable bearing based on the coupling of a rolling element entity and a nonlinear spring, specifically including the following steps:

[0036] Step S1: Obtain the loads on the turntable bearing and determine the positions of the main thrust roller and the secondary thrust roller with the maximum load.

[0037] Step S2: Establish a space rectangular coordinate system. As Figure 3 shown, establish a finite element contact model of the roller / raceway and perform mesh division. The element type of the mesh division is C3D8I element. According to the actual working state of the turntable bearing, completely constrain the six degrees of freedom of the lower raceway, release the degrees of freedom of the upper raceway and the roller along the y-axis direction, and then apply a series of loads to the upper raceway along the negative y-axis direction to simulate and analyze the deformation of the roller under different loads, so as to obtain the nonlinear stiffness coefficient curve of the spring that can be equivalent to the main thrust roller and the nonlinear stiffness coefficient curve of the spring that can be equivalent to the secondary thrust roller. AsFigure 4 As shown, according to the dimensions and load-bearing characteristics of the slewing bearing, it is determined that both the main thrust rollers and the auxiliary thrust rollers are equivalent to four non-linear springs evenly distributed.

[0038] Step S3: Establish an overall finite element model of the slewing bearing. Among them, the main thrust rollers and the auxiliary thrust rollers at the position with the maximum load are both modeled as solid models, while the remaining rollers are respectively equivalent to the corresponding non-linear springs described above. The equivalent roller / raceway contact model can be simplified as Figure 5 shown.

[0039] Step S4: Apply external loads to the established finite element model of the slewing bearing and carry out simulation calculations.

[0040] Step S5: Obtain the finite element calculation results and analyze the overall load distribution state and local stress distribution state of the slewing bearing.

[0041] In this embodiment, the non-linear stiffness coefficient of the spring used to equivalent the rolling elements is obtained by simulation methods, and it can also be obtained by experimental means in other embodiments. In addition, the method of the present application is also applicable to other types of slewing bearings other than the three-row cylindrical roller slewing bearing.

[0042] Since the stress distribution state at the position with the maximum load of the slewing bearing is the key information for the strength analysis of the slewing bearing, therefore, in the method of the present application, the main thrust rollers and the auxiliary thrust rollers with the maximum load are modeled as solid roller models, and the meshing of the rollers and the rings at this position is refined to ensure the accuracy of the analysis of the local stress state; while the rollers in other parts are all equivalent to non-linear springs to reduce the number of meshes of the finite element model and improve the convergence of the model.

[0043] To further illustrate the effect of the method of the present application, for the slewing bearings of the same model and specification, two other finite element models are established for analysis. One of the finite element models has the rollers not equivalent to non-linear springs and are all solid roller models, which is Scheme A; while the other finite element model has all the rollers equivalent to non-linear springs, which is Scheme B.

[0044] At the same time, in Scheme A, Scheme B and the scheme of the present application, the meshing method and quantity of the rings of the slewing bearing are exactly the same. In Scheme A and the scheme of the present application, the meshing method and quantity of the rollers of the slewing bearing are exactly the same, and the same simulation conditions are set for calculation. Finally, the comparison results of the required time for the finite element simulation of the three schemes are shown in Table 1.

[0045] Table 1 Statistical table of simulation time for Scheme A, Scheme B and the scheme of the present application

[0046]

[0047]

[0048] It can be clearly seen from the data in Table 1 that the time required for the finite element model analysis of the roller without non-linear spring equivalent treatment is much longer than that of the other two models. Moreover, as the number of meshes continues to increase, when it exceeds one million elements, the calculation process has extremely high requirements for the performance of computer hardware, and the calculation results are difficult to converge, resulting in extremely low calculation efficiency.

[0049] Both the finite element model analysis of the roller with all solid models and the solution of the present application can obtain the overall load distribution state of the slewing bearing. However, obviously, the former cannot obtain the key information required for bearing strength verification - the stress distribution state at the part of the bearing with the maximum load. Therefore, it can only analyze by establishing a local roller / raceway finite element contact model again and inputting the load. However, this method cannot ensure that the input load is the same as the non-uniformly distributed load on the roller under the working state, and it is difficult to ensure that the positional relationship between the two rings and the roller in the established model is the same as the true positional relationship between the ring and the roller in the slewing bearing under the working state. That is, there will be a certain degree of angle between the ring and the roller under the load state of the slewing bearing, and it is difficult to ensure the same angle between the ring and the roller in the secondary modeling. In contrast, the latter can directly obtain the stress distribution state at the roller with the maximum load during the overall simulation analysis of the slewing bearing. Since the local roller / raceway finite element contact model is not simplified, the obtained results can more accurately reflect the true stress distribution state of the roller / raceway. On the above basis, the time used by the solution of the present application is very close to that of Scheme B. Even if the time consumption of the solution of the present application is slightly longer, on the premise of ensuring the calculation accuracy, its calculation efficiency is within an acceptable range.

[0050] The above are only some embodiments of the present application, and thus do not limit the patent protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Within the spirit and principle of the present application, any improvement or equivalent replacement made by using the content of the specification and drawings of the present application, directly or indirectly applied to other related technical fields, shall be included in the patent protection scope of the present application.

Claims

1. A method for analyzing a slewing bearing based on the coupling of rolling element entities and non-linear springs. A number of rolling elements are provided in the slewing bearing. Characterized in that, The method includes the following steps: Step S1: Obtain the load on the slewing bearing and determine the position of the rolling element with the maximum load. Step S2: Establish an overall finite element model of the slewing bearing, in which the rolling element with the maximum load is modeled as a solid model, and the remaining rolling elements are equivalent to non-linear springs. Step S3: Apply external loads to the established finite element model of the slewing bearing and carry out simulation calculations. Step S4: Obtain the finite element calculation results and analyze the overall load distribution state and local stress distribution state of the slewing bearing.

2. The method for analyzing a slewing bearing based on the coupling of rolling element entities and non-linear springs according to claim 1, Characterized in that, Before the step S2), it is necessary to obtain the non-linear stiffness coefficient curve of the non-linear spring through finite element analysis or experimental methods and determine the number of non-linear springs used to equivalent a single rolling element.

3. The method for analyzing a slewing bearing based on the coupling of rolling element entities and non-linear springs according to claim 2, Characterized in that, The process of obtaining the non-linear stiffness coefficient curve and the number of non-linear springs is as follows: Establish a finite element contact model of the roller / raceway and a space rectangular coordinate system, and carry out mesh division on the finite element contact model of the roller / raceway; According to the actual working conditions, constrain or release the degrees of freedom of the raceway and the roller in the x-axis, y-axis and z-axis directions respectively; Apply loads to the raceway, simulate and analyze the deformation of the roller under different loads, and obtain the non-linear stiffness coefficient curve of the non-linear spring used to equivalent the roller; According to the size and load characteristics of the slewing bearing, determine that the roller is equivalent to N equally spaced non-linear springs.

4. The method for analyzing a slewing bearing based on the coupling of rolling element entities and non-linear springs according to claim 3, Characterized in that, The element type of the mesh division is C3D8I element.

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