An analysis method for the force and service life of the main bearing cage of a shield machine

Abstract

The present invention provides an analysis method for the force and life of the shield machine main bearing cage. The analysis method for the force aspect includes the following steps: Step S1, establish a three-dimensional rigid body dynamics model; Step S2, design the assembly for Parasolid format export; Step S3, establish the parameters of kinematic pairs, contact pairs, external loads, and rotational speeds; Step S4, run the ADAMS simulation and output the contact force; Step S5, establish a 1 / 2 three-dimensional model of the cage A; Step S6, import the 1 / 2 three-dimensional model of the cage A into the ABAQUS software; Step S7, obtain the stress and strain of the cage A. The analysis method for the life aspect of the present invention further includes Step S8, solve the life of each dangerous area, and take the minimum value of all life calculation values as the life of the cage A. The present invention can improve the accuracy and efficiency of the analysis of the force and life of the shield machine main bearing cage at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of shield machine main bearings, and in particular to a method for analyzing the stress and life of a shield machine main bearing retainer. Background Art

[0002] Economic development depends on the interconnection of all things, and transportation interconnection is a key link. Subways and tunnels are a popular choice in transportation interconnection because they have less impact on ground buildings and ecology. The efficient and safe excavation of subways and tunnels is inseparable from shield machines. The main bearing is the power component of the shield machine, and its performance will directly affect the efficiency of the shield machine. Therefore, how to analyze and design the main bearing is very critical to the service performance of the shield machine.

[0003] The cage is one of the main parts of the shield machine main bearing, which is mainly used to separate rollers and guide rollers. Since the working condition of the shield machine main bearing is low speed and heavy load, the roller directly bears a large load and transfers part of the load to the cage in the form of collision and friction. Therefore, the strength of the cage directly affects the performance of the main bearing. However, there is a gap between the cage and the roller and ring, and the stress state is related to the position. Therefore, the dynamic analysis of the cage is essential.

[0004] Compared with other bearings, shield machine main bearings have the following characteristics: 1) Large diameter, up to 6m; 2) Large differences in parts size, on the one hand, the ring diameter can reach more than 6m, while the smallest roller diameter may be only 50mm; 3) Both axial and radial load-bearing rollers; 4) The cage is not an integral ring, but arc-shaped segments, with no connection between segments. Therefore, the force model of shield machine main bearings is much more complicated than other small bearings.

[0005] In the prior art, when the main bearing is subjected to dynamic analysis, only a few methods consider the cage, and the accuracy of the analysis results needs to be improved. For example, the patent with publication number CN112329177 A discloses a modeling and simulation method for the dynamic model of the main bearing of a shield machine, which uses a rigid-flexible coupling model to solve the vibration signal of the main bearing, but the flexible model actually only uses a few degrees of freedom and it is difficult to fully describe the deformation. The patent with publication number CN 113076614 A discloses a method for calculating the life of a needle roller bearing cage that combines bearing dynamics and FEM. It establishes a dynamic equation around the cage force, forming a data transfer from dynamic analysis to finite element analysis, but because the external load does not directly act on the cage, it is difficult for this patent to reflect the effect of the external load on the cage. Summary of the invention

[0006] The object of the present invention is to provide an analysis method for the force and service life of the main bearing cage of a shield machine, which is used to solve the force condition and service life of the main bearing cage of the shield machine, and improve the accuracy and efficiency of the analysis results. The specific technical solution is as follows:

[0007] In the first aspect, the present invention provides an analysis method for the force of the main bearing cage of a shield machine, which includes the following steps:

[0008] Step S1: Establish a rigid body dynamics three-dimensional model in CERO software according to the actual size of the main bearing of the shield machine

[0009] The main bearing includes a raceway, type I cage, type II cage, type III cage, type I roller, type II roller and type III roller; wherein, the raceway includes an inner ring, a first outer ring and a second outer ring;

[0010] Select any one of the type I cage, type II cage and type III cage as the object of attention for subsequent step analysis, denote the selected any one cage as cage A, and divide the contact area of cage A into regions;

[0011] Step S2: Export the assembly composed of the raceway, type I cage, type II cage, type III cage, type I roller, type II roller and type III roller in Parasolid format;

[0012] Step S3: Use the Python secondary development tool to import the assembly exported in step S2 into ADAMS software, and establish the following parameters: kinematic pairs, contact pairs, external loads and rotational speed;

[0013] Among them, the kinematic pairs include a revolute pair between the inner ring and the ground, a sliding pair between the first outer ring and the ground, a fixed pair between the second outer ring and the ground, and a fixed pair between the cage A skeleton and the contact area;

[0014] The contact pairs include roller-cage, cage-raceway, roller-raceway and cage-cage;

[0015] The external loads include axial force, radial force, overturning moment and torque;

[0016] The rotational speed is applied to the revolute pair between the inner ring and the ground;

[0017] Step S4: Input the parameters established in step S3 into ADAMS software, run the ADAMS simulation, extract the force and motion conditions of the contact area of cage A changing with time under the external load from the calculation results of step S3, and output the contact force;

[0018] Step S5: Establish a 1 / 2 three-dimensional model of the cage A in CREO software, and the 1 / 2 of the cage A is separated by the normal plane of the arc tangent of the cage A as the symmetry plane;

[0019] Step S6: Import the 1 / 2 three-dimensional model of the cage A into ABAQUS software, denoted as model A, and define the material properties;

[0020] Step S7: Solve the finite element model using implicit dynamics to obtain the stress and strain of model A, that is, the stress and strain of the cage A.

[0021] Furthermore, in step S3, the interaction between each contact pair is collision contact, with the stiffness set to 100000 N / mm, the damping to 50 N·s / mm, the exponent to 1.5, the penetration depth to 1.5 mm, the static friction critical speed to 0.1 mm / s, the dynamic friction critical speed to 10 mm / s, the static friction coefficient to 0.08, the dynamic friction coefficient to 0.05, and the distribution coefficient to 0.15.

[0022] Furthermore, in step S3, the rotational speed is set to 2 r / min.

[0023] Furthermore, in step S6, in model A, model A is divided into several hexahedron meshes. The meshes correspond to the elements in the finite element model in step S7, and the nodes correspond to the element nodes in the finite element model in step S7. After the load output from step S4 is simplified by the rain flow counting method, it is used as the boundary condition of model A, and the load application position is determined by the Python secondary development tool; meanwhile, symmetric constraints are applied to the symmetry plane of the model A.

[0024] Furthermore, the mesh size is 1 mm.

[0025] Furthermore, in step S4, the position where the external load acts on the cage A is approximately determined as follows:

[0026] a) The force application positions of the type I rollers, type II rollers, and type III rollers on the cage A

[0027] At the center of the radial side wall of the pocket, select a row of nodes as the force application position of the cylindrical surface of the type I rollers, type II rollers, or type III rollers on the cage A; on the center line of the axial side wall of the pocket, randomly select points by the Python secondary development tool, and expand the area to a four-connected domain about this point as the force application position of the end face of the type I rollers, type II rollers, or type III rollers on the cage A;

[0028] b) The force application positions of the raceway on the cage A

[0029] The acting position of the ring rib and the cage A is the guiding surface of the cage A, and the contact form is line contact. All possible contact lines on the guiding surface of the cage A are extracted, and a contact line is randomly selected as the acting position of the ring rib and the cage A through the Python secondary development tool. The length of the contact line is related to the size of the guiding surface;

[0030] c) The force application position of the adjacent cage A on the cage A

[0031] The acting area of the adjacent cage A on the analyzed cage A is the end face of the cage A, and the actual acting position is a certain straight line on the end face. All possible contact lines on the end face of the cage A are extracted, and a contact line is randomly selected as the acting position of the remaining cage A and the cage A through the Python secondary development tool. The contact surface size is related to the end face size of the cage A.

[0032] In a second aspect, the present invention provides an analysis method for the life of the shield machine main bearing cage, which includes the analysis method for the force on the shield machine main bearing cage described above, and further includes step S8 after step S7;

[0033] The step S8 is to estimate the fatigue parameters of the material of model A according to the Seeger approximate algorithm, find the dangerous areas at different times based on the finite element solution, solve the life of each dangerous area based on the Corten-Dolan cumulative damage criterion, and take the minimum value of all life calculation values as the life of the cage A.

[0034] Further, in step S8, the tensile strength of the material of model A is 600 MPa and the elastic modulus is 215 GPa.

[0035] Applying the technical solution of the present invention has at least the following beneficial effects:

[0036] (1) The present invention proposes an analysis method for the force and life of the shield machine main bearing cage. Starting from the unique structure of the main bearing cage, this method jointly solves step by step through rigid body dynamics, finite element method and fatigue life algorithm to obtain the external load, stress, strain and life under the working conditions of the cage, while improving the accuracy and efficiency of the analysis results. In addition, since this analysis method does not need to perform finite element analysis on the overall main bearing, and the size of the segmented cage for the finite element analysis object is relatively fixed, therefore, as the size of the main bearing increases, the calculation cost of this analysis method will not increase significantly. The present invention can be used not only for analyzing the shield machine main bearing, but also for analyzing other bearings with the characteristics of segmented cages.

[0037] (2) The present invention proposes an approximate estimation method for the external load application position of the cage A. The analysis object is only the cage. To avoid its rigid body displacement, fixed constraints are applied to its symmetry plane. To reflect the response of the cage under variable loads, dynamic solution is adopted in the analysis method of the present invention. Since the model to be solved is relatively simple, the cost of adopting implicit dynamic solution will not be too large. At the same time, this approximate estimation method also improves the accuracy of finite element method modeling.

[0038] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0040] Figure 1 is a schematic structural diagram of a main bearing of a shield machine in Embodiment 1 of the present invention;

[0041] Among them, 1. Second outer ring, 2. Inner ring, 3. First outer ring, 4. Type I roller, 5. Type III roller, 6. Type II roller, 7. Type I cage, 8. Type III cage, 9. Type II cage;

[0042] Figure 2 is the position where the cylindrical surface of the roller of Type I roller, Type II roller or Type III roller applies force to the cage;

[0043] Figure 3 is the position where the end face of the roller of Type I roller, Type II roller or Type III roller applies force to the cage;

[0044] Figure 4 is the position where the raceway applies force to the cage A;

[0045] Figure 5 is the position where the adjacent cage A applies force to the cage A;

[0046] Among them, in Figure 2-5 the meshes correspond to the elements in the finite element model in step S7, and the nodes correspond to the element nodes in the finite element model in step S7. The nodes marked with hollow circles are the force application positions;

[0047] Figure 6 is a schematic diagram of the geometric segmentation of the cage A;

[0048] Figure 7 is a schematic diagram of the external load received by the assembly. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0050] Embodiment 1:

[0051] Refer to Figure 1 , an analysis method for the force-bearing of the cage of a shield machine main bearing, comprising the following steps:

[0052] Step S1: Establish a rigid body dynamics three-dimensional model in CERO software according to the actual size of the shield machine main bearing

[0053] The main bearing includes a raceway, a type-I cage 7, a type-II cage 9, a type-III cage 8, type-I rollers 4, type-II rollers 6, and type-III rollers 5; wherein, the raceway includes an inner ring 2, a first outer ring 3, and a second outer ring 1;

[0054] Select any one of the type-I cage, type-II cage, and type-III cage as the object of concern for subsequent step analysis, denote the selected any one cage as cage A, and perform regional segmentation on the contact area of cage A; Refer to Figure 6 , after the regional segmentation of the contact area of cage A, the contact area of cage A is specifically divided into a cage-cage contact area 1-1, an outer ring-cage contact area 1-2, an inner ring-cage contact area 1-3, a roller cylindrical surface-cage contact area 1-4, and a roller end face-cage contact area 1-5. After the regional segmentation, the matching between contact pairs and contact areas is realized to clarify the acting positions of subsequent contact forces;

[0055] Step S2: Export the assembly composed of the raceway, type-I cage, type-II cage, type-III cage, type-I rollers, type-II rollers, and type-III rollers in Parasolid format; after exporting to the Parasolid intermediate format, number all the parts of the assembly to ensure that sub-parts with the same size have searchable and unique names;

[0056] Step S3: Use the Python secondary development tool to import the assembly exported in step S2 into ADAMS software, and establish the following parameters: kinematic pairs, contact pairs, external loads, and rotational speeds;

[0057] Among them, the kinematic pairs include a rotational pair between the inner ring and the ground, a sliding pair between the first outer ring and the ground, a fixed pair between the second outer ring and the ground, and a fixed pair between the cage A skeleton and the contact area;

[0058] The contact pairs include roller-cage, cage-ring, roller-ring and cage-cage, specifically including the contact pairs between type I rollers - type I cages, type II rollers - type II cages, type III rollers - type III cages, type I cages - inner rings, type I cages - first outer rings, type II cages - inner rings, type II cages - second outer rings, type III cages - inner rings, type III cages - first outer rings, type III cages - second outer rings, type I rollers - inner rings, type I rollers - first outer rings, type II rollers - inner rings, type II rollers - second outer rings, type III rollers - inner rings, type III rollers - first outer rings, type III rollers - second outer rings, type I cages - type I cages, type II cages - type II cages, and type III cages - type III cages; the parameters of the contact pairs depend on the materials of the contact pairs and the lubrication conditions;

[0059] See Figure 7 , the external load is specifically the axial force F a , radial force F r , tipping moment M and torque N;

[0060] The rotational speed is applied to the revolute pair between the inner ring and the ground;

[0061] Step S4: Input the parameters established in step S3 into the ADAMS software, run the ADAMS simulation, extract the force and motion conditions of the contact area of cage A under the external load over time from the calculation results of step S3, and output the contact force;

[0062] Step S5: Establish a 1 / 2 three-dimensional model of cage A in the CREO software, and the 1 / 2 of cage A is separated by the normal plane of the arc tangent of cage A as the symmetry plane;

[0063] Step S6: Import the 1 / 2 three-dimensional model of cage A into the ABAQUS software, denoted as model A, and define the material properties;

[0064] Step S7: Use the implicit dynamics to solve the finite element model to obtain the stress and strain of model A, that is, the stress and strain of cage A.

[0065] In step S3, the interaction between the contact pairs is collision contact, with the stiffness set to 100000 N / mm, the damping to 50 N·s / mm, the exponent to 1.5, the penetration depth to 1.5 mm, the static friction critical speed to 0.1 mm / s, the dynamic friction critical speed to 10 mm / s, the static friction coefficient to 0.08, the dynamic friction coefficient to 0.05, and the distribution coefficient to 0.15.

[0066] In step S3, the rotational speed is set to 2 r / min.

[0067] In step S6, in Model A, Model A is divided into a number of hexahedral meshes. The meshes correspond to the elements in the finite element model in step S7, and the nodes correspond to the element nodes in the finite element model in step S7. The load output from step S4 is simplified by the rain flow counting method and used as the boundary condition of Model A. The load application position is determined by a Python secondary development tool. Meanwhile, symmetric constraints are applied to the symmetry plane of the said Model A.

[0068] The mesh size is 1 mm.

[0069] In step S4, the positions of the external loads acting on the cage A are approximately determined as follows:

[0070] a) The force application positions of the type I rollers, type II rollers, and type III rollers on the cage A

[0071] Refer to Figure 2 , at the center of the radial side wall of the pocket, select a row of nodes (the node distance is the same as the effective length of the type I rollers, type II rollers, or type III rollers) as the force application position of the cylindrical surface of the type I rollers, type II rollers, or type III rollers on the cage A; refer to Figure 3 , on the center line of the axial side wall of the pocket, randomly select points by a Python secondary development tool and expand the area into a four-connected domain about this point as the force application position of the end face of the type I rollers, type II rollers, or type III rollers on the cage A;

[0072] b) The force application position of the raceway

[0073] Refer to Figure 4 , the acting position of the raceway rib and the cage A is the guiding surface of the cage A, and the contact form is line contact. Extract all possible contact lines on the guiding surface of the cage A, and randomly select a contact line by a Python secondary development tool as the acting position of the raceway rib and the cage A. The contact line length is related to the size of the guiding surface;

[0074] c) The force application position of the cage A

[0075] Refer to Figure 5 , the acting area of the adjacent cage A on the analyzed cage A is the end face of the cage A, and the actual acting position is a certain straight line on the end face. Extract all possible contact lines on the end face of the cage A, and randomly select a contact line by a Python secondary development tool as the acting position of the other cage A and the cage A. The contact surface size is related to the size of the end face of the cage A.

[0076] An analysis method for the life of the cage of the main bearing of a shield machine, including the analysis method for the force on the cage of the main bearing of the shield machine, and further including step S8 after step S7;

[0077] Step S8 is to estimate the fatigue parameters of the material of model A according to the Seeger approximation algorithm, find the dangerous areas at different times based on the finite element solution, solve the life of each dangerous area based on the Corten-Dolan cumulative damage criterion, and take the minimum value of all life calculation values as the life of cage A.

[0078] In step S8, the tensile strength of the material of model A is 600 MPa and the elastic modulus is 215 GPa.

[0079] The fatigue parameters of the material of model A obtained by using the Seeger approximation algorithm in step S8 are shown in Table 1.

[0080] Table 1

[0081] Fatigue parameter value <![CDATA[Fatigue strength factor σ f (MPa)]]> 900 Fatigue strength index b -0.087 <![CDATA[Fatigue toughness factor ε f > 0.59 Fatigue ductility index c -0.58 Cyclic strain hardening factor K'(MPa) 990 Cyclic strain hardening index n' 0.15

[0082] Using the analysis method for the force and life of the cage of the main bearing of the shield machine described in Embodiment 1, according to the simulation results, the maximum Mises stress of cage A changing with time is 36.4 MPa, and the calculated life value exceeds 10 7 cycles, which is about 2×10 5 h, exceeding the design life of 10,000 h of the main bearing of the shield machine. Therefore, the life of the cage analyzed by simulation meets the requirements.

[0083] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An analysis method for the force-bearing of the main bearing cage of a shield machine, characterized in that It includes the following steps: Step S1: Establish a rigid body dynamics three-dimensional model in CERO software according to the actual size of the main bearing of the shield machine The main bearing includes a raceway, a type I cage, a type II cage, a type III cage, type I rollers, type II rollers and type III rollers; among them, the raceway includes an inner ring, a first outer ring and a second outer ring; Select any one of the type I cage, type II cage and type III cage as the object of concern for subsequent step analysis, denote the selected any one cage as cage A, and divide the contact area of cage A; Step S2: Export the assembly composed of the raceway, type I cage, type II cage, type III cage, type I rollers, type II rollers and type III rollers in Parasolid format; Step S3: Use the Python secondary development tool to import the assembly exported in step S2 into ADAMS software, and establish the following parameters: kinematic pairs, contact pairs, external loads and rotational speed; Among them, the kinematic pairs include a revolute pair between the inner ring and the ground, a sliding pair between the first outer ring and the ground, a fixed pair between the second outer ring and the ground, and a fixed pair between the cage A skeleton and the contact area; The contact pairs include roller-cage, cage-raceway, roller-raceway and cage-cage; The external loads include axial force, radial force, overturning moment and torque; The rotational speed is applied to the revolute pair between the inner ring and the ground; Step S4: Input the parameters established in step S3 into ADAMS software, run the ADAMS simulation, extract the force and motion conditions of the contact area of cage A changing with time under the external load from the calculation results of step S3, and output the contact force; Step S5: Establish a 1 / 2 three-dimensional model of cage A in CREO software, and the 1 / 2 of cage A is separated by the normal plane of the arc tangent of cage A; Step S6: Import the 1 / 2 three-dimensional model of cage A into ABAQUS software, denote it as model A, and define the material properties; Step S7: Use the implicit dynamics to solve the finite element model to obtain the stress and strain of model A, that is, the stress and strain of cage A.

2. The analysis method of the shield machine main bearing cage in terms of force according to claim 1, characterized in that In step S3, the interaction between each contact pair is collision contact, the stiffness is set to 100000N / mm, the damping is 50N·s / mm, the exponent is 1.5, the penetration depth is 1.5mm, the static friction critical speed is 0.1mm / s, the dynamic friction critical speed is 10mm / s, the static friction coefficient is 0.08, the dynamic friction coefficient is 0.05, and the distribution coefficient is 0.

15.

3. The analysis method of the shield machine main bearing cage in terms of force according to claim 2, characterized in that In step S3, the rotational speed is set to 2r / min.

4. The analysis method of the shield machine main bearing cage in terms of force according to claim 3, characterized in that, In step S6, in model A, model A is divided into several hexahedron meshes, the meshes correspond to the elements in the finite element model in step S7, the nodes correspond to the element nodes in the finite element model in step S7, the load output from step S4 is simplified by the rain flow counting method and used as the boundary condition of model A, and the load application position is determined by the Python secondary development tool; at the same time, a symmetry constraint is applied to the symmetry plane of the model A.

5. The analysis method of the shield machine main bearing cage in terms of force and life according to claim 4, characterized in that The grid size is 1 mm.

6. The analysis method of the shield machine main bearing cage in terms of force according to claim 5, characterized in that, In step S4, the position of the external load acting on the cage A is approximately determined as follows: a) The force application positions of the type I rollers, type II rollers, and type III rollers on the cage A At the center of the radial sidewall of the pocket, select a row of nodes as the force application position of the cylindrical surface of the type I rollers, type II rollers, or type III rollers on the cage A; on the center line of the axial sidewall of the pocket, randomly select points by the Python secondary development tool, and expand the area into a four-connected domain about this point as the force application position of the end face of the type I rollers, type II rollers, or type III rollers on the cage A; b) The force application position of the raceway on the cage A The acting position of the raceway rib and the cage A is the guiding surface of the cage A, and the contact form is line contact. Extract all possible contact lines on the guiding surface of the cage A, and randomly select a contact line by the Python secondary development tool as the acting position of the raceway rib and the cage A. The length of the contact line is related to the size of the guiding surface; c) The force application position of the adjacent cage A on the cage A The acting area of the adjacent cage A on the analyzed cage A is the end face of the cage A, and the actual acting position is a certain straight line on the end face. Extract all possible contact lines on the end face of the cage A, and randomly select a contact line by the Python secondary development tool as the acting position of the remaining cage A and the cage A. The contact surface size is related to the end face size of the cage A.

7. A method for analyzing the service life of the shield machine main bearing cage, characterized in that It includes the analysis method of the main bearing cage of the shield machine in terms of force as described in any one of claims 1-6, and further includes step S8 after step S7; The step S8 is to estimate the fatigue parameters of the material of model A according to the Seeger approximation algorithm, find the dangerous areas at different times based on the finite element solution, solve the life of each dangerous area based on the Corten-Dolan cumulative damage criterion, and take the minimum value of all life calculation values as the life of the cage A.

8. The analysis method for the life of the shield machine main bearing cage according to claim 7, characterized in that, In step S8, the tensile strength of the material of the model A is 600 MPa and the elastic modulus is 215 GPa.

Images