Methods for evaluating vehicle axle assembly performance and designing assembly parameters

Abstract

The present invention discloses a method for evaluating the assembly performance of a vehicle axle and designing assembly parameters, comprising the following steps: step S1, equating a wheel with a hub diameter of #imgabs0# to a cylinder with a diameter of #imgabs1#: #imgabs2#, where k is an equivalent coefficient; step S2, calculating a theoretical wheel-axle joint length L and an equivalent wheel-axle joint length #imgabs3#; step S3, calculating an equivalent coefficient k; step S4, determining the contact stress p of the wheel with a web structure using an equivalent cylinder contact stress calculation formula; step S5, calculating a limit range of the contact stress; step S6, comparing the contact stress calculated using the equivalent cylinder contact stress calculation formula with the limit range of the wheel-axle contact stress, and using the result as a standard for evaluating the assembly performance of the wheel axle. The present invention can equate a wheel with a web structure to a standard cylinder, determine the wheel contact stress of the web structure using the equivalent cylinder contact stress calculation formula, and use the contact stress to evaluate the reliability of the wheel axle assembly and design assembly parameters.

Description

Technical Field

[0001] The invention relates to a method for evaluating the assembly performance of a vehicle axle and designing assembly parameters, and belongs to the technical field of vehicle axle assembly. Background Art

[0002] Wheels and axles are crucial components of rail vehicles, and the quality of their assembly directly impacts driving safety. Wheelset assembly is a crucial step in wheelset production. Most wheelset assembly, both domestically and internationally, utilizes a press-fit method. Railway vehicle wheels and axles are assembled together using an interference fit. The contact stress between the wheel and axle is a key factor in ensuring wheel and axle assembly reliability.

[0003] Currently, most wheels are designed based on experience. However, the randomness of experience often leads to large calculation deviations. The wheel is a non-standard cylindrical structure, and there is no standard calculation formula for contact stress, which makes it difficult to calculate. As a result, there is no quick and effective evaluation method for assembly performance, which often leads to unreasonable structural size design and uncoordinated stiffness.

[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 evaluating the assembly performance of a vehicle axle and designing assembly parameters. The method can equate the wheel with a web structure to a standard cylinder, use the equivalent cylinder contact stress calculation formula to determine the wheel contact stress of the web structure, and use the contact stress to evaluate the reliability of the axle assembly and design the assembly parameters.

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

[0007] A method for evaluating the assembly performance of a vehicle axle comprises the following steps:

[0008] Step S1, the hub diameter is The wheel is equivalent to a diameter of Cylinder: , k is the equivalent coefficient;

[0009] Step S2: Calculate the theoretical wheel-axle connection length L and the equivalent wheel-axle connection length ;

[0010] in, + , = + ,

[0011] = wheel axle combined length - web thickness, is the web thickness;

[0012] Step S3, calculate the equivalent coefficient k: ;

[0013] Step S4: Use the equivalent cylindrical contact stress calculation formula to determine the contact stress p of the wheel of the web structure: ,

[0014] Where, —Interference; E—elastic modulus; —equivalent diameter; —Contact radius, b= / 2; - wheel aperture; —Axle inner diameter radius;

[0015] Step S5, calculating the limit range of contact stress;

[0016] In step S6, the contact stress calculated using the equivalent cylindrical contact stress calculation formula is compared with the limit range of the wheel axle contact stress, and this is used as a standard for evaluating the wheel axle assembly performance.

[0017] Furthermore, when the contact stress calculated using the equivalent cylindrical contact stress calculation formula is within the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance meets the requirements; when the contact stress calculated using the equivalent cylindrical contact stress calculation formula exceeds the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance does not meet the requirements.

[0018] Furthermore, in step S5, according to the standard TB / T1463, the maximum oil injection pressure during assembly of a one-piece wheel is: 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 =136Mpa;

[0019] The minimum back pressure applied during the back pressure test after the axle is assembled is: F=1.2K For the integral wheel, K is 5.2, and the wheel-axle assembly friction force f=μ·p·π· L×10 -3 , by F<μ·p·π· L×10 -3 , determine the wheel axle contact stress p to satisfy:

[0020] p>6.24x10 3 / (μ·π·L) Mpa;

[0021] 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.

[0022] Therefore, the limit range of wheel axle contact stress is:

[0023] 6.24x10 3 / (μ·π·L) <p<136 Mpa。

[0024] Furthermore, the correction formula for the wheel contact stress p is: ,

[0025] Where, —Interference; E—elastic modulus; —equivalent diameter; —Contact radius, b= / 2; —Axle inner diameter radius.

[0026] A method for designing vehicle wheel axle assembly parameters is provided. When the wheel axle contact stress p calculated by the equivalent cylindrical contact stress calculation formula is greater than 136 MPa, the wheel axle assembly parameters are adjusted by reducing the interference or increasing the wheel axle joint length L. When the wheel axle contact stress p calculated by the equivalent cylindrical contact stress calculation formula is less than 6.24x10 3 / (μ·π·L), adjust by increasing the interference or reducing the wheel-axle connection length L.

[0027] Furthermore, based on the experience of locomotive operation, combined with the transmission torque and the performance of the axle material, the adjustable range of the interference is set to the wheel aperture. 1.1-1.3‰ times; based on design experience, the adjustable range of the wheel axle connection length L is set to 200-250mm.

[0028] 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 connection length L, the structural stiffness of the wheel is adjusted;

[0029] When adjusting the structural stiffness of the wheel, first adjust the web thickness and hub thickness, then adjust the wheel diameter and rim thickness.

[0030] Furthermore, when the axle contact stress p is too large, the structural stiffness of the wheel is reduced, and the web thickness, hub thickness, wheel diameter and rim thickness are reduced; when the axle contact stress p is too small, the structural stiffness of the wheel is increased, and the web thickness, hub thickness, wheel diameter and rim thickness are increased.

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

[0032] 1. The contact stress is calculated using the equivalent cylindrical contact stress calculation formula and further corrected using a correction factor. When the calculated contact stress is within the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance meets the requirements. When the contact stress calculated using the equivalent cylindrical contact stress calculation formula exceeds the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance does not meet the requirements, thereby achieving an evaluation of the vehicle wheel axle assembly performance.

[0033] 2. By adding and subtracting the interference fit, the wheel-axle connection length L, and the structural stiffness 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, the wheel-axle parameters are designed.

[0034] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the wheel.

[0036] In the figure,

[0037] 1- rim, 2- web, 3- hub. DETAILED DESCRIPTION

[0038] 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.

[0039] like Figure 1 As shown, the present invention provides a method for evaluating the assembly performance of a vehicle axle, comprising the following steps:

[0040] Step S1, the diameter of the hub 3 is The wheel is equivalent to a diameter of Cylinder: , k is the equivalent coefficient;

[0041] Most wheels are designed as web structures. There is no theoretical calculation method for contact stress of wheels with web structures. In order to calculate contact stress, the outer diameter of the wheel is divided into three diameters of the hub. and outer diameter Two parts, such as Figure 1 shown.

[0042] The structural stiffness of the wheel is greater than the diameter The stiffness of a cylinder with a diameter less than The cylindrical stiffness of When calculating the contact stress for the outer diameter of the cylinder, the value will be smaller than the actual value. When contact stress is calculated for the outside diameter of a cylinder, its value will be greater than the actual value.

[0043] The contact stress of the wheel with web structure is equivalent to the calculation diameter Contact stress of the wheel with a cylindrical structure.

[0044] Step S2: Calculate the theoretical wheel-axle connection length L and the equivalent wheel-axle connection length ;in,

[0045] + , = + ,

[0046] = wheel axle combined length - web thickness, is the web thickness, such as Figure 1 As shown;

[0047] Step S3, calculate the equivalent coefficient k: ;

[0048] Step S4: Use the equivalent cylindrical contact stress calculation formula to determine the contact stress p of the wheel of the web structure: ,

[0049] Where, —Interference; E is the elastic modulus; —equivalent diameter; —Contact radius (b= / 2, - wheel aperture); —Axle inner hole radius (the axle inner hole radius is the radius of the center hole of the hollow axle, solid axle =0).

[0050] The wheel contact stress calculated in step S4 is a theoretical value. In order to verify the improved algorithm for the contact stress of the web structure wheel-axle interference fit, finite element simulation is used for inspection and analysis. To make the contact stress closer to the actual value, a correction factor is introduced when calculating the contact stress using the equivalent cylindrical contact stress calculation formula; the correction factor is determined to be 1.2 using finite element technology simulation test analysis.

[0051] The modified formula for calculating the contact stress p of the wheel of the web structure is obtained as follows: ,

[0052] Where, —Interference; E—elastic modulus; —equivalent diameter; —Contact radius (b= / 2); —Axle inner diameter radius.

[0053] Step S5, calculate the limit range of contact stress; contact stress is the main factor affecting the press-fitting force. When it is higher than the oil injection pressure, press-fitting cannot be performed or the press-fitting force is too large. Therefore, the limit range of contact stress is determined by deducing the oil injection pressure and the counter pressure. Standard TB / T1463 stipulates that the maximum oil injection pressure for the assembly of a monoblock wheel is: 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 , i.e. 136Mpa; after the axle is assembled, a back pressure test is carried out. The axle must not be loose during the back pressure test. The minimum back pressure applied during the test is: F=1.2K (The back pressure during the test is 1.2K Implementation), the standard stipulates that for integral wheels, K is 5.2, that is, F=6.24 , - wheel aperture. Wheel-axle assembly friction f = μ·p·π· L×10 -3 , by F<μ·p·π· L×10 -3 , determine the wheel axle contact stress p to satisfy:

[0054] p>6.24x10 3 / (μ·π·L) Mpa;

[0055] 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;

[0056] Therefore, the limit range of wheel axle contact stress is:

[0057] 6.24x10 3 / (μ·π·L) <p<136 Mpa。

[0058] Step S6, comparing the contact stress calculated using the equivalent cylindrical contact stress calculation formula with the limit range of the wheel axle contact stress, and using this as a standard for evaluating the wheel axle assembly performance;

[0059] When the contact stress calculated using the equivalent cylindrical contact stress calculation formula is within the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance meets the requirements; when the contact stress calculated using the equivalent cylindrical contact stress calculation formula exceeds the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance does not meet the requirements.

[0060] The present invention also provides a method for designing vehicle axle assembly parameters:

[0061] When the wheel-axle contact stress p calculated by the equivalent cylindrical contact stress calculation formula is greater than 136 MPa, it can be adjusted by reducing the interference or increasing the wheel-axle connection length L; when the wheel-axle contact stress p calculated by the equivalent cylindrical contact stress calculation formula is less than 6.24x10 3 / (μ·π·L), adjust by increasing the interference or reducing the wheel-axle connection length L.

[0062] According to the experience of locomotive operation, combined with the transmission torque and the performance of the axle material, the adjustable range of the interference is set to the wheel aperture. 1.1-1.3‰ times; based on design experience, the adjustable range of the wheel axle connection length L is set to 200-250mm.

[0063] 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), the wheel's structural stiffness should be adjusted. To do this, first adjust the thickness of the web 2 and hub 3, then adjust the wheel diameter and the thickness of the rim 1. If the axle contact stress p is too large, reduce the wheel's structural stiffness by reducing the thickness of the web 2, hub 3, wheel 1 diameter, and rim 1. If the axle contact stress p is too small, increase the wheel's structural stiffness by increasing the thickness of the web 2, hub 3, wheel 1 diameter, and rim 1.

[0064] 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.

[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 evaluating the assembly performance of a vehicle axle, characterized by: The steps include: Step S1, the hub diameter is The wheel is equivalent to a diameter of Cylinder: , k is the equivalent coefficient; Step S2: Calculate the theoretical wheel-axle connection length L and the equivalent wheel-axle connection length ; in, + , = + , = wheel axle combined length - web thickness, is the web thickness; Step S3, calculate the equivalent coefficient k: ; Step S4: Use the equivalent cylindrical contact stress calculation formula to determine the contact stress p of the wheel of the web structure: ， Where, —Interference; E—elastic modulus; —equivalent diameter; —Contact radius, b= / 2; - wheel aperture; —Axle inner diameter radius; Step S5, calculating the limit range of contact stress; In step S6, the contact stress calculated using the equivalent cylindrical contact stress calculation formula is compared with the limit range of the wheel axle contact stress, and this is used as a standard for evaluating the wheel axle assembly performance.

2. The method for evaluating vehicle axle assembly performance according to claim 1, wherein: When the contact stress calculated using the equivalent cylindrical contact stress calculation formula is within the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance meets the requirements; when the contact stress calculated using the equivalent cylindrical contact stress calculation formula exceeds the limit range of the wheel axle contact stress, the vehicle wheel axle assembly performance does not meet the requirements.

3. The method for evaluating vehicle axle assembly performance according to claim 1, wherein: In step S5, according to the standard TB / T1463, the maximum oil injection pressure during the assembly of the integral wheel is: 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 =136Mpa; The minimum back pressure applied during the back pressure test after the axle is assembled is: F=1.2K For the integral wheel, K is 5.2, and the wheel-axle assembly friction force f=μ·p·π· L×10 -3 , by F<μ·p·π· 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。 4. The method for evaluating vehicle axle assembly performance according to claim 1, wherein: The correction formula for the wheel contact stress p is: , Where, —Interference; E—elastic modulus; —equivalent diameter; —Contact radius, b= / 2; —Axle inner diameter radius.

5. A method for designing vehicle axle assembly parameters, characterized in that: The designed method is based on the method for evaluating the assembly performance of a vehicle axle according to any one of claims 1 to 4: When the wheel-axle contact stress p calculated by the equivalent cylindrical contact stress calculation formula is greater than 136 MPa, it can be adjusted by reducing the interference or increasing the wheel-axle connection length L; when the wheel-axle contact stress p calculated by the equivalent cylindrical contact stress is less than 6.24x10 3 / (μ·π·L), adjust by increasing the interference or reducing the wheel-axle connection length L.

6. The method for designing vehicle axle assembly parameters according to claim 5, wherein: According to the experience of locomotive operation, combined with the transmission torque and the performance of the axle material, the adjustable range of the interference is set to the wheel aperture. 1.1-1.3‰ times; based on design experience, the adjustable range of the wheel axle connection length L is set to 200-250mm.

7. The method for designing vehicle axle assembly parameters according to claim 5, 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 connection 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 vehicle axle assembly parameters according to claim 7, wherein: When the wheel-axle contact stress p is too large, the structural stiffness of the wheel is reduced, and the web thickness, hub thickness, wheel diameter and rim thickness are reduced; when the wheel-axle contact stress p is too small, the structural stiffness of the wheel is increased, and the web thickness, hub thickness, wheel diameter and rim thickness are increased.

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