Calculation of vehicle axle contact stress, inspection of assembly parameters and design methods

Abstract

The present invention discloses a method for calculating contact stress of a vehicle wheel axle, inspecting and designing assembly performance, comprising the following steps: determining assembly parameters that affect contact stress; determining the value ranges of various assembly parameters that affect contact stress based on design experience; taking three values for each assembly parameter within its value range to establish an orthogonal parameter model; establishing a contact stress database under different assembly parameters through finite element simulation technology; and performing learning and training on the established contact stress database, the mapping relationship between assembly parameters and contact stress, and weighted calculation to obtain a contact stress calculation model. The present invention establishes a mapping relationship between the assembly parameters of the wheel axle and the contact stress through a method combining theory with simulation, thereby providing a simple wheel axle contact stress calculation method, inspecting and designing the wheel axle assembly performance through the wheel axle contact stress, and guiding the design and evaluation of parameters of locomotive wheel axles.

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 a key step in wheelset production. Most wheelset assembly methods, both domestically and internationally, use press assembly. However, during the press assembly process, unreasonable structural or axle parameter design often lead to unqualified phenomena such as excessive or insufficient press force, fluctuating press curves, and loose axle counterpressure, which greatly reduces production efficiency and wastes production costs. The above problems are closely related to the axle assembly parameters. The assembly parameters have a direct effect on the wheel structural stiffness and axle contact stress. Inconsistent structural stiffness will cause unstable press force and press oil pressure, loose axle counterpressure, and axle sluggishness 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 the assembly parameters, which is highly random and often leads to unreasonable structural size design and inconsistent stiffness. Currently, there is no quick and effective evaluation method or evaluation index for the assembly parameters.

[0004] In summary, the existing technology has obvious inconveniences and defects in actual use, so it is necessary to improve it. Summary of the Invention

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

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for calculating contact stress of a vehicle wheel axle comprises the following steps: Step S1, determining assembly parameters that affect the contact stress: web thickness B2, hub thickness B3, hub plate fillet R, interference, wheel axle coupling length L, and wheel diameter D;

[0008] Step S2, determining the value ranges of various assembly parameters that affect contact stress based on design experience;

[0009] 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).

[0010] 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;

[0011] 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;

[0012] Step S5, establishing a mapping relationship between assembly parameters and contact stress and weighted calculation through an artificial neural network calculation model;

[0013] 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.

[0014] Furthermore, 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.

[0015] 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.

[0016] A method for testing the assembly performance of a vehicle axle comprises: step T1, setting a set of assembly parameters according to an empirical range, and calculating the contact stress using the contact stress calculation model;

[0017] Step T2, calculating the limit range of contact stress;

[0018] 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.

[0019] Furthermore, 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;

[0020] 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:

[0021] p>6.24x10 3 / (μ·π·L) Mpa;

[0022] 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.

[0023] Therefore, the limit range of wheel axle contact stress is:

[0024] 6.24x10 3 / (μ·π·L) <p<136 Mpa。

[0025] A vehicle axle design method, when the axle contact stress p calculated using the contact stress calculation model is greater than 136 MPa, is adjusted by reducing the interference or increasing the axle coupling length L;

[0026] 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.

[0027] Furthermore, when 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, the structural stiffness of the wheel is adjusted;

[0028] When adjusting the structural stiffness of the wheel, first adjust the web thickness and hub thickness, then adjust the wheel diameter and rim thickness.

[0029] 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.

[0030] Furthermore, based on locomotive operation experience combined with the transmission torque and axle material properties, the adjustable range of the interference fit 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.

[0031] After adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0032] 1. The contact stress calculation model can be used to conveniently calculate the wheel axle contact stress by inputting the assembly parameters of the wheel axle (Xi, Yi, Zi, Hi, Li, Gi). This eliminates the need for complex finite element analysis to calculate the contact stress, making the calculation more convenient and easier to operate.

[0033] 2. The wheel axle contact stress can be quickly calculated using the contact stress calculation model. The calculated wheel axle contact stress can be conveniently compared with the limit range of the wheel axle contact stress to test the assembly performance of the wheel axle.

[0034] 3. If the calculated wheel-axle contact stress p is too large or too small, the interference fit, wheel-axle coupling length L, and structural stiffness are added or subtracted within a certain range. 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 to design the wheel-axle parameters.

[0035] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural diagram of the wheel and axle assembly.

[0037] In the figure,

[0038] 1- Wheel, 2- Rim, 3- Web, 4- Hub, 5- Axle. DETAILED DESCRIPTION

[0039] 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.

[0040] like Figure 1 As shown, the present invention provides a method for calculating the contact stress of a vehicle axle, comprising the following steps:

[0041] Step S1, determining the assembly parameters that affect the contact stress: the thickness B2 of the web 3, the thickness B3 of the hub 4, the hub plate fillet R, the interference, the wheel-axle connection length L, and the diameter D of the wheel 1;

[0042] Axle assembly parameters include wheel structural parameters and axle assembly parameters. Wheel structural parameters include: wheel diameter (D), rim thickness (B1), web thickness (B2), hub thickness (B3), wheel aperture (d), and hub-web transition (abbreviated as hub-plate fillet R). Axle assembly parameters include: interference fit, wheel-axle coupling length (L), press-fit force, and oil injection pressure. Each assembly parameter has varying degrees of influence on contact stress. The six parameters with the greatest impact are: web thickness (B2), hub thickness (B3), hub fillet R, interference fit, wheel-axle coupling length (L), and wheel diameter (D).

[0043] Step S2: Determine the value ranges of various assembly parameters that affect 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 connection length L is: 200-250mm, and the value range of the wheel 1 diameter D is: 950-1250mm.

[0044] In 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, an orthogonal test method is used to establish an orthogonal parameter model (Xi, Yi, Zi, Hi, Li, Gi), where i is 1, 2, or 3.

[0045] Step S4: extract the contact stress under each orthogonal parameter model through finite element simulation technology, and establish a contact stress database (Xi, Yi, Zi, Hi, Li, Gi, Pi) under different assembly parameters.

[0046] In step S5, a mapping relationship and weighted calculation between assembly parameters and contact stress are established 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 in the hidden layer. The contact stress is used as the output parameter of the output layer.

[0047] 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. During the training process, convergence is achieved 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, and the contact stress calculation model is obtained.

[0048] By using the contact stress calculation model, the wheel axle contact stress can be conveniently 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.

[0049] The present invention also provides a method for inspecting vehicle axle assembly parameters, comprising the following steps:

[0050] Step T1, setting a set of assembly parameters according to an empirical range, and calculating the contact stress using the contact stress calculation model;

[0051] Step T2, calculating the limit range of contact stress; contact stress is the main factor affecting the press-fitting force. When contact stress exceeds the oil injection pressure, press-fitting cannot be performed or the press-fitting force is excessive. Therefore, the limit range of contact stress is determined by deducing the oil injection pressure and the counter pressure;

[0052] 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; after the wheel axle is assembled, a back pressure test is conducted. 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 K for integral wheels is 5.2, that is, F = 6.24d, where d is the wheel aperture. The friction force of the wheel axle assembly is 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:

[0053] p>6.24x10 3 / (μ·π·L) Mpa;

[0054] Where: L is the wheel-axle joint length, μ is the wheel-axle friction coefficient, and μ is 0.1 when the wheel-axle is press-assembled by oil injection according to the wheel-axle back pressure test results; units of each parameter: F-kN, f-kN, p-Mpa, d f -mm, L-mm;

[0055] Therefore, the limit range of wheel axle contact stress is:

[0056] 6.24x10 3 / (μ·π·L) <p<136 Mpa。

[0057] Step T3, comparing the wheel axle contact stress calculated in step T1 with the limit range of the wheel axle contact stress to check the assembly performance of the wheel axle;

[0058] 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 connection 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.

[0059] Based on locomotive operation experience, combined with the transmission torque and axle material properties, the adjustable range of the interference fit is set to 1.1-1.3‰ times the wheel aperture, that is, 1.1-1.3‰d; based on design experience, the adjustable range of the wheel axle connection length L is set to 200-250mm.

[0060] If the axle contact stress still cannot meet its limit within the adjustable range of the interference fit and the wheel-axle connection length (L), adjust the wheel's structural stiffness. To do this, first adjust the web thickness and hub thickness, then adjust the wheel diameter and rim thickness. If the axle contact stress p is too large, reduce the wheel's structural stiffness by reducing the web thickness, hub thickness, wheel diameter, and rim thickness. If the axle contact stress p is too small, increase the wheel's structural stiffness by increasing the web thickness, hub thickness, wheel diameter, and rim thickness.

[0061] 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. The stress is then compared with the limit range of the wheel-axle contact stress.

[0062] The present invention also includes an assembly parameter visualization design system, which compiles the contact stress calculation model into a visualization design system through computer language, including an input interface and an output interface.

[0063] First, enter the wheel diameter and axle diameter parameters in the input interface to determine the interference fit. Then, use the system to set a set of initial parameters based on empirical ranges: web thickness, hub thickness, hub fillet parameters, and wheel-axle joint length. Once these settings are complete, the output wheel-axle contact stress can be calculated.

[0064] The wheel-axle contact stress is then tested, and initial parameter optimization suggestions are provided. When contact stress is high, the output is: increase the wheel-axle coupling length, reduce the interference fit, or reduce structural stiffness (reduce web thickness, hub thickness, hub plate fillet, and rim thickness). When contact stress is low, the output is: reduce the wheel-axle coupling length, increase the interference fit, or increase structural stiffness (increase web thickness, hub thickness, hub plate fillet, and rim thickness). Parameters are optimized according to the optimization suggestions until all requirements are met. Based on the set assembly parameters, the design system automatically calculates the back-pressure test parameters.

[0065] The foregoing is an example of the best mode of carrying out the present invention. Any portion not described in detail herein is common knowledge within the skill of one of ordinary skill in the art. The scope of protection of the present invention is determined by the claims. Any equivalent transformation based on the technical teachings of the present invention is also within the scope of protection 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 inspecting the assembly performance of a vehicle axle is provided based on the method for calculating the contact stress of a vehicle axle according to any one of claims 1 to 3, characterized in that: 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 is provided according to the method for calculating the contact stress of a vehicle axle according to any one of claims 1 to 3, characterized in that: 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. Where μ is the axle friction coefficient.

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.

Images