Method for calculating contact stress of vehicle axle, checking assembly parameters and designing

Abstract

The invention discloses a vehicle axle contact stress calculation and assembly performance inspection and design method, which comprises the following steps of: determining assembly parameters influencing the contact stress; determining the value range of each assembly parameter influencing the contact stress according to design experience; three numerical values of each assembly parameter are taken in the value range of the assembly parameter, and an orthogonal parameter model is established; establishing a contact stress database under different assembly parameters through a finite element simulation technology; learning and training are conducted on the established contact stress database, the mapping relation between the assembling parameters and the contact stress and weighted calculation, a contact stress calculation model is obtained, the mapping relation between the assembling parameters and the contact stress of the wheel shaft is established through the method of combining theory and simulation, and therefore the simple and convenient wheel shaft contact stress calculation method is provided; the wheel axle assembly performance is inspected and designed through the wheel axle contact stress, and the method is used for guiding design and evaluation of parameters of the locomotive wheel axle.

Description

Technical Field

[0001] The invention relates to a method for calculating contact stress of a vehicle axle, inspecting assembly performance and designing the same, and belongs to the technical field of vehicle axle assembly parameter design. Background Art

[0002] Wheels and axles are important components of rail vehicles, and their assembly quality directly affects driving safety. Wheelset assembly is an important part of wheelset production. Most wheelset assemblies at home and abroad adopt the pressure assembly method. However, the pressing process often leads to unqualified phenomena such as excessive or insufficient pressing force, fluctuation of the pressing curve, loosening of the wheel axle counterpressure, etc. due to unreasonable structural or wheel axle parameter design, which greatly reduces production efficiency and wastes production costs. The above problems are closely related to the wheel axle assembly parameters. The assembly parameters have a direct effect on the wheel structural stiffness and the wheel axle contact stress. Inharmonious structural stiffness will cause problems such as unstable pressing force and pressing oil pressure, loosening of the wheel axle counterpressure, and slowness of the wheel axle during the wheel axle assembly process.

[0003] Since the wheel is a non-standard cylinder, there is no standard calculation formula for the wheel-axle contact stress. Currently, locomotive wheels mostly use empirical design to determine assembly parameters, which is highly random and often leads to unreasonable structural dimension design and uncoordinated stiffness. Currently, there is no quick and effective evaluation method and evaluation index for assembly parameters.

[0004] In summary, the prior art obviously has inconveniences and defects in practical use, so it is necessary to improve it. Summary of the invention

[0005] In view of the deficiencies in the background technology, the present invention provides a method for calculating the contact stress of a vehicle axle, inspecting and designing the assembly performance. By combining theory with simulation, a mapping relationship between the assembly parameters of the axle and the contact stress is established, thereby providing a simple method for calculating the contact stress of the axle. The axle assembly performance is inspected and designed through the axle contact stress, which is used to guide the design and evaluation of the parameters of the locomotive axle.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for calculating the contact stress of a vehicle wheel axle comprises the following steps: step S1, determining assembly parameters affecting the contact stress: web thickness B2, hub thickness B3, hub plate fillet R, interference, wheel axle combination length L, wheel diameter D; Step S2, determining the value range of each assembly parameter affecting the contact stress according to design experience; Step S3, each assembly parameter takes 3 values ​​within its value range, and the parameters are grouped as follows: web thickness (X1, X2, X3), hub thickness (Y1, Y2, Y3), hub plate fillet (Z1, Z2, Z3), interference (H1, H2, H3), wheel-axle connection length (L1, L2, L3), wheel diameter (G1, G2, G3); Then, the orthogonal test method was used to establish the orthogonal parameter model (Xi, Yi, Zi, Hi, Li, Gi), where i is 1, 2, 3; Step S4, extracting the contact stress under each orthogonal parameter model by finite element simulation technology, and establishing a contact stress database (Xi, Yi, Zi, Hi, Li, Gi, Pi) under different assembly parameters; Step S5, establishing a mapping relationship and weighted calculation between assembly parameters and contact stress through an artificial neural network calculation model; Step S6, using the contact stress database (Xi, Yi, Zi, Hi, Li, Gi, Pi) established in step S4 to learn and train the mapping relationship and weighted calculation between the assembly parameters and the contact stress in step S5, when the difference between the contact stress output by the output layer of the artificial neural network calculation model and the contact stress in the contact stress database meets the requirements, convergence is achieved, and the contact stress calculation model is obtained.

[0007] Further, in step S2, the value range of the web thickness B2 is: 15-30mm, the value range of the hub thickness B3 is: 50-100mm, the value range of the hub plate radius R is: 0-200mm, the value range of the interference amount is: 1.1‰-1.3‰d, d is the wheel aperture, the value range of the wheel axle connection length L is: 200-250mm, and the value range of the wheel diameter D is: 950-1250mm.

[0008] Furthermore, in step S5, the assembly parameters (Xi, Yi, Zi, Hi, Li, Gi) are used as the input layer of the artificial neural network calculation model, the assembly parameters of the input layer are mapped and weighted in the hidden layer, and the contact stress is used as the output parameter of the output layer of the artificial neural network calculation model.

[0009] A method for testing the assembly performance of a vehicle axle, step T1, setting a set of assembly parameters according to an empirical range, and calculating the contact stress using the contact stress calculation model; Step T2, calculating the limit range of contact stress; Step T3, comparing the wheel axle contact stress calculated in step T1 with the limit range of the wheel axle contact stress, thereby checking the assembly performance of the wheel axle.

[0010] Furthermore, in step T2, according to standard TBT1463, the maximum contact stress of the wheel axle should not be greater than P 压 =170Mpa. Based on the test and assembly experience and taking into account the pressure loss, it is determined that the maximum contact stress of the wheel axle should not be greater than 0.8P 压 =136 Mpa; The minimum back pressure applied during the back pressure test after the wheel axle is assembled is: F=1.2Kd, d is the wheel hole diameter, the integral wheel diameter K is 5.2, and the wheel axle assembly friction force f=μ·p·π·d·L×10 -3 , by F < μ·p·π·d· L×10 -3 , determine the wheel-axle contact stress p to satisfy: p>6.24x10 3 / (μ·π·L)Mpa; Where: L is the wheel-axle joint length, μ is the wheel-axle friction coefficient. According to the wheel-axle reverse pressure test results, μ is 0.1 when the wheel-axle is press-assembled by oil injection. Therefore, the limit range of wheel axle contact stress is: 6.24x10 3 / (μ·π·L) <p<136 Mpa。

[0011] A method for designing a wheel axle of a vehicle, when the wheel axle contact stress p calculated by the contact stress calculation model is greater than 136 MPa, the wheel axle contact stress p is adjusted by reducing the interference or increasing the wheel axle connection length L; When the wheel axle contact stress p calculated by the contact stress calculation model is less than 6.24x10 3 / (μ·π·L), adjust by increasing the interference or reducing the wheel-axle connection length L.

[0012] Furthermore, when the wheel-axle contact stress still cannot meet its limit range within the adjustable range of the interference and the wheel-axle combination length L, the structural stiffness of the wheel is adjusted; When adjusting the structural stiffness of the wheel, first adjust the web thickness and hub thickness, then adjust the wheel diameter and rim thickness.

[0013] Furthermore, when the axle contact stress p is too large, the structural stiffness of the wheel is reduced by reducing the web thickness, hub thickness, wheel diameter and rim thickness. When the axle contact stress p is too small, the structural stiffness of the wheel is increased by increasing the web thickness, hub thickness, wheel diameter and rim thickness.

[0014] Furthermore, based on locomotive operation experience combined with transmission torque and axle material properties, the adjustable range of the interference is set to 1.1-1.3‰d, where d is the wheel aperture; based on design experience, the adjustable range of the wheel-axle connection length L is set to 200-250mm.

[0015] After adopting the above technical solution, the present invention has the following advantages compared with the prior art: 1. By using the contact stress calculation model, the wheel axle contact stress can be easily calculated by inputting the assembly parameters of the wheel axle (Xi, Yi, Zi, Hi, Li, Gi), thereby eliminating the need to calculate the contact stress using complex finite element analysis, and making the operation more simple and easy.

[0016] 2. The wheel axle contact stress can be quickly calculated using the contact stress calculation model, and the calculated wheel axle contact stress can be conveniently compared with the limit range of the wheel axle contact stress to check the assembly performance of the wheel axle.

[0017] 3. When the calculated wheel-axle contact stress p is too large or too small, the interference, wheel-axle connection length L and structural stiffness are added and subtracted within a certain range, and the corresponding wheel-axle contact stress is calculated using the contact stress calculation model, and compared with the limit range of the wheel-axle contact stress, so as to design the wheel-axle parameters.

[0018] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural diagram of the wheel and axle assembly.

[0020] In the figure, 1- wheel, 2- rim, 3- belly plate, 4- hub, 5- axle. DETAILED DESCRIPTION

[0021] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0022] like Figure 1 As shown, the present invention provides a method for calculating the contact stress of a vehicle axle, comprising the following steps: Step S1, determining assembly parameters that affect contact stress: web 3 thickness B2, hub 4 thickness B3, hub plate fillet R, interference, wheel-axle connection length L, wheel 1 diameter D; The wheel axle assembly parameters include wheel structure parameters and wheel axle assembly parameters. The wheel structure parameters include: wheel 1 diameter D, rim 2 thickness B1, web 3 thickness B2, hub 4 thickness B3, wheel aperture d, and transition part between hub and web (abbreviated as: hub plate fillet R); the wheel axle assembly parameters include: interference, wheel axle combination length L, press force, and oil injection pressure. Each assembly parameter has different degrees of influence on contact stress. The six assembly parameters that have the greatest influence on contact stress are: web 3 thickness B2, hub 4 thickness B3, hub plate fillet R, interference, wheel axle combination length L, and wheel 1 diameter D.

[0023] Step S2, determine the value ranges of various assembly parameters that affect the contact stress based on design experience. Based on experience, the value range of the web 3 thickness B2 is: 15-30mm, the value range of the hub 4 thickness B3 is: 50-100mm, the value range of the hub plate fillet R is: 0-200mm, the value range of the interference amount is: 1.1‰-1.3‰d (d is the wheel aperture), the value range of the wheel axle combination length L is: 200-250mm, and the value range of the wheel 1 diameter D is: 950-1250mm.

[0024] Step S3, each assembly parameter takes 3 values ​​within its value range, and the parameters are grouped as follows: web thickness (X1, X2, X3), hub thickness (Y1, Y2, Y3), hub plate fillet (Z1, Z2, Z3), interference (H1, H2, H3), wheel-axle connection length (L1, L2, L3), wheel diameter (G1, G2, G3); then, an orthogonal test method is used to establish an orthogonal parameter model (Xi, Yi, Zi, Hi, Li, Gi), where i is 1, 2, 3; Step S4, extracting the contact stress under each orthogonal parameter model by finite element simulation technology, and establishing a contact stress database (Xi, Yi, Zi, Hi, Li, Gi, Pi) under different assembly parameters.

[0025] Step S5, establishing a mapping relationship and weighted calculation between assembly parameters and contact stress through an artificial neural network calculation model, the artificial neural network calculation model includes an input layer, a hidden layer and an output layer, the assembly parameters (Xi, Yi, Zi, Hi, Li, Gi) are used as the input layer, the assembly parameters of the input layer are mapped and weighted calculated in the hidden layer, and the contact stress is used as the output parameter of the output layer.

[0026] Step S6, using the contact stress database (Xi, Yi, Zi, Hi, Li, Gi, Pi) established in step S4 to perform learning and training on the mapping relationship and weighted calculation between the assembly parameters and the contact stress in step S5. During the learning and training process, when the difference between the contact stress output by the output layer of the artificial neural network calculation model and the contact stress in the contact stress database meets the requirements, convergence is achieved, and the contact stress calculation model is obtained.

[0027] By using the contact stress calculation model, the wheel axle contact stress can be easily calculated by inputting the assembly parameters of the wheel axle (Xi, Yi, Zi, Hi, Li, Gi), thereby eliminating the need to calculate the contact stress through complex finite element analysis.

[0028] The present invention also provides a method for inspecting assembly parameters of a vehicle axle, comprising the following steps: Step T1, setting a set of assembly parameters according to an empirical range, and calculating the contact stress using the contact stress calculation model; Step T2, calculating the limit range of contact stress; contact stress is the main factor affecting the press-fitting force. When the contact stress is higher than the oil injection pressure, press-fitting cannot be performed or the press-fitting force is too large. Thus, the limit range of contact stress is determined by deriving the oil injection pressure and the counter pressure. According to standard TBT1463, the maximum contact stress of the wheel axle should not be greater than P 压 =170Mpa. Based on the test and assembly experience and taking into account the pressure loss, it is determined that the maximum contact stress of the wheel axle should not be greater than 0.8P 压 =136 Mpa; after the wheel axle is assembled, the back pressure test is carried out. The wheel axle must not be loose during the back pressure test. The minimum back pressure applied during the test is: F=1.2Kd (the back pressure during the test is implemented according to 1.2Kd). The standard stipulates that the integral wheel K is 5.2, that is, F=6.24d, d-wheel aperture. Wheel axle assembly friction f=μ·p·π·d· L×10 -3 , by F < μ·p·π·d· L×10 -3 , determine the wheel-axle contact stress p to satisfy: p>6.24x10 3 / (μ·π·L)Mpa; Where: L-wheel-axle joint length, μ-wheel-axle friction coefficient, according to the wheel-axle back pressure test results, when the wheel-axle is oil-filled and pressed, μ is 0.1; units of each parameter: F-kN, f-kN, p-Mpa, d f -mm, L-mm; Therefore, the limit range of wheel-axle contact stress is: 6.24x10 3 / (μ·π·L) <p<136 Mpa。

[0029] Step T3, comparing the wheel axle contact stress calculated in step T1 with the limit range of the wheel axle contact stress, thereby checking the assembly performance of the wheel axle; The present invention also provides a method for designing vehicle wheel axle assembly parameters. When the wheel axle contact stress p calculated in step T1 is greater than 136 MPa, the wheel axle assembly parameters are adjusted by reducing the interference or increasing the wheel axle assembly length L. When the wheel axle contact stress p calculated in step T1 is less than 6.24x10 3 / (μ·π·L), adjust by increasing the interference or reducing the wheel-axle connection length L.

[0030] According to locomotive operation experience combined with transmission torque and axle material properties, the adjustable range of interference is set to 1.1-1.3‰ times the wheel aperture, i.e. 1.1-1.3‰d; according to design experience, the adjustable range of wheel-axle connection length L is set to 200-250mm.

[0031] If the wheel-axle contact stress still cannot meet its limit range within the adjustable range of the interference and the wheel-axle combination length L, then adjust the structural stiffness of the wheel. When adjusting the structural stiffness of the wheel, first adjust the web thickness and the hub thickness, and then adjust the wheel diameter and the rim thickness. When the wheel-axle contact stress p is too large, reduce the structural stiffness of the wheel, reduce the web thickness, hub thickness, wheel diameter and rim thickness. When the wheel-axle contact stress p is too small, increase the structural stiffness of the wheel, increase the web thickness, hub thickness, wheel diameter and rim thickness.

[0032] The axle parameters are designed by performing addition and subtraction calculations on the interference fit, the wheel-axle connection length L and the structural stiffness within a certain range, and using the contact stress calculation model to calculate the corresponding wheel-axle contact stress, and comparing it with the limit range of the wheel-axle contact stress.

[0033] The present invention also includes an assembly parameter visualization design system, which compiles the contact stress calculation model into a visualization design system through a computer language, including an input interface and an output interface. First, input the wheel diameter and axle 5 diameter parameters in the input interface to determine the interference; set a set of initial parameters based on the empirical range through the system: web thickness, hub thickness, hub plate fillet parameters, and wheel-axle connection length. After the settings are completed, the output wheel-axle contact stress can be calculated; Then the wheel-axle contact stress is tested and initial parameter optimization suggestions are given. When the contact stress is large, the output is: increase the wheel-axle connection length, reduce the interference, or reduce the structural stiffness (reduce the web thickness, hub thickness, hub plate fillet, and rim thickness); when the wheel-axle contact stress is small, the output is: reduce the wheel-axle connection length, increase the interference, or increase the structural stiffness (increase the web thickness, hub thickness, hub plate fillet, and rim thickness). Parameters are optimized according to the optimization suggestions until all requirements are met. For the set assembly parameters, the design system can automatically calculate the back pressure test parameters.

[0034] The above is an example of the best implementation of the present invention, and the parts not described in detail are common knowledge of ordinary technicians in the field. The protection scope of the present invention shall be based on the content of the claims, and any equivalent transformation based on the technical enlightenment of the present invention is also within the protection scope of the present invention.

Claims

1. A method for calculating vehicle axle contact stress, characterized by: The following steps are included: Step S1, determining the assembly parameters that affect the contact stress: web thickness B2, hub thickness B3, hub plate fillet R, interference, wheel-axle connection length L, wheel diameter D; Step S2, determining the value ranges of various assembly parameters that affect contact stress based on design experience; Step S3: Each assembly parameter takes three values ​​within its range. The parameters are grouped as follows: web thickness (X1, X2, X3), hub thickness (Y1, Y2, Y3), hub plate fillet (Z1, Z2, Z3), interference (H1, H2, H3), wheel-axle coupling length (L1, L2, L3), and wheel diameter (G1, G2, G3). Then, the orthogonal test method was used to establish the orthogonal parameter model (Xi, Yi, Zi, Hi, Li, Gi), where i is 1, 2, or 3; Step S4, extracting the contact stress under each orthogonal parameter model through finite element simulation technology, and establishing a contact stress database (Xi, Yi, Zi, Hi, Li, Gi, Pi) under different assembly parameters; Step S5, establishing a mapping relationship between assembly parameters and contact stress and weighted calculation through an artificial neural network calculation model; In step S6, the mapping relationship between the assembly parameters and the contact stress and the weighted calculation in step S5 are trained using the contact stress database (Xi, Yi, Zi, Hi, Li, Gi, Pi) established in step S4. When the difference between the contact stress output by the output layer of the artificial neural network calculation model and the contact stress in the contact stress database meets the requirements, convergence is achieved, and the contact stress calculation model is obtained.

2. The method for calculating vehicle axle contact stress according to claim 1, wherein: In step S2, the value range of the web thickness B2 is: 15-30mm, the value range of the hub thickness B3 is: 50-100mm, the value range of the hub plate radius R is: 0-200mm, the value range of the interference is: 1.1‰-1.3‰d, d is the wheel aperture, the value range of the wheel axle connection length L is: 200-250mm, and the value range of the wheel diameter D is: 950-1250mm.

3. The method for calculating vehicle axle contact stress according to claim 1, wherein: In step S5, the assembly parameters (Xi, Yi, Zi, Hi, Li, Gi) are used as the input layer of the artificial neural network calculation model, the assembly parameters of the input layer are mapped and weighted in the hidden layer, and the contact stress is used as the output parameter of the output layer of the artificial neural network calculation model.

4. A method for testing the assembly performance of a vehicle axle, characterized by: Step T1, setting a set of assembly parameters according to an empirical range, and calculating the contact stress using the contact stress calculation model; Step T2, calculating the limit range of contact stress; In step T3, the wheel axle contact stress calculated in step T1 is compared with the limit range of the wheel axle contact stress to check the assembly performance of the wheel axle.

5. The method for testing the assembly performance of a vehicle axle according to claim 4, wherein: In step T2, according to the standard TBT1463, the maximum contact stress of the wheel axle should not be greater than P 压 =170Mpa. Based on test and assembly experience and taking into account pressure loss, it is determined that the maximum contact stress of the wheel axle should not be greater than 0.8P 压 =136 MPa; The minimum back pressure applied during the back pressure test after the wheel axle is assembled is: F=1.2Kd, d is the wheel hole diameter, the integral wheel diameter K is 5.2, and the wheel axle assembly friction force f=μ·p·π·d·L×10 -3 , by F<μ·p·π·d· L×10 -3 , determine the wheel axle contact stress p to satisfy: p>6.24x10 3 / (µ·π·L)Mba: Where: L is the wheel-axle joint length, μ is the wheel-axle friction coefficient. According to the wheel-axle back pressure test results, μ is set to 0.1 when the wheel-axle is press-assembled by oil injection. Therefore, the limit range of wheel axle contact stress is: 6.24x10 3 / (μ·π·L) <p<136 Mpa。 6. A method for designing a vehicle axle, characterized by: When the wheel-axle contact stress p calculated using the contact stress calculation model is greater than 136 MPa, the wheel-axle contact stress is adjusted by reducing the interference or increasing the wheel-axle connection length L; When the wheel axle contact stress p calculated by the contact stress calculation model is less than 6.24x10 3 / (μ·π·L), adjust by increasing the interference or reducing the wheel-axle connection length L.

7. The method for designing a vehicle axle according to claim 6, wherein: If the wheel-axle contact stress still cannot meet its limit range within the adjustable range of the interference fit and the wheel-axle joint length L, adjust the structural stiffness of the wheel; When adjusting the structural stiffness of the wheel, first adjust the web thickness and hub thickness, then adjust the wheel diameter and rim thickness.

8. The method for designing a vehicle axle according to claim 7, wherein: When the wheel-axle contact stress p is too large, the structural stiffness of the wheel is reduced by reducing the web thickness, hub thickness, wheel diameter and rim thickness. When the wheel-axle contact stress p is too small, the structural stiffness of the wheel is increased by increasing the web thickness, hub thickness, wheel diameter and rim thickness.

9. The method for designing a vehicle axle according to claim 6, wherein: Based on locomotive operation experience, combined with transmission torque and axle material properties, the adjustable range of the interference is set to 1.1-1.3‰d, where d is the wheel aperture; based on design experience, the adjustable range of the axle connection length L is set to 200-250mm.

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