Vehicle axle assembly performance evaluation and assembly parameter design method

Abstract

The invention discloses a vehicle axle assembly performance evaluation and assembly parameter design method, which comprises the following steps: S1, enabling a wheel with the hub diameter of # imgabs0 # to be equivalent to a cylinder with the diameter of # imgabs1 #: # imgabs2 #, k being an equivalent coefficient; s2, calculating a theoretical axle combination length L and an equivalent axle combination length # imgabs3 #; s3, calculating an equivalent coefficient k; s4, determining the contact stress p of the wheel with the web structure by adopting an equivalent cylinder contact stress calculation formula; S5, calculating the limit range of the contact stress; and S6, comparing the contact stress calculated by adopting an equivalent cylinder contact stress calculation formula with the limit range of the contact stress of the wheel shaft, and taking the result as a standard for evaluating the assembly performance of the wheel shaft. According to the method, the wheel of the web structure can be equivalent to a standard cylinder, the wheel contact stress of the web structure is determined by adopting an equivalent cylinder contact stress calculation formula, the wheel axle assembly reliability is evaluated by utilizing the contact stress, and the assembly parameters are designed.

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 important components of rail vehicles, and their assembly quality directly affects driving safety. Wheelset assembly is an important part of wheelset production. Most wheelset assembly at home and abroad adopts the pressure assembly method. The wheels and axles of railway vehicles are assembled together by interference fit. The contact stress between the wheel and axle is the main factor to ensure the reliability of wheel and axle assembly.

[0003] Currently, wheels are mostly designed empirically. 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 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 evaluating the assembly performance of a vehicle axle and designing assembly parameters. The wheel of a web structure can be equivalent to a standard cylinder, and the wheel contact stress of the web structure is determined by using the equivalent cylinder contact stress calculation formula. The contact stress is used to evaluate the reliability of the wheel axle assembly and to design assembly parameters.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for evaluating the assembly performance of a vehicle axle comprises the following steps: 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: , ,i=1,2, In the formula, - wheel aperture; - equivalent diameter; - Poisson's ratio of the contained part; Step S4, using the equivalent cylindrical contact stress calculation formula to determine the contact stress p of the wheel of the web structure: , In the formula, —Interference; E—elastic modulus; — equivalent diameter; —Contact radius, b= / 2; —Axle inner diameter radius; Step S5, calculating the limit range of contact stress; Step S6, comparing the contact stress calculated by 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.

[0007] 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.

[0008] Further, 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 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 =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)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。

[0009] Furthermore, the correction formula of the wheel contact stress p is: , In the formula, —Interference; E—elastic modulus; — equivalent diameter; —Contact radius, b= / 2; —Axle inner diameter radius.

[0010] A method for designing vehicle wheel axle assembly parameters, when the wheel axle contact stress p calculated by the equivalent cylindrical contact stress calculation formula is greater than 136 MPa, it is 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.

[0011] Furthermore, based on the experience of locomotive operation, combined with the transmission torque and the performance of the wheel axle material, the adjustable range of the interference is set to the wheel aperture 1.1-1.3‰ times; according to design experience, the adjustable range of the wheel-axle combination length L is set to 200-250mm.

[0012] 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 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, 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.

[0014] After adopting the above technical solution, the present invention has the following advantages compared with the prior art: 1. The contact stress is calculated using the equivalent cylindrical contact stress calculation formula and further corrected by the correction coefficient. 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 realizing the evaluation of the vehicle wheel axle assembly performance.

[0015] 2. By adding and subtracting 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, the wheel-axle parameters are designed.

[0016] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the wheel.

[0018] In the figure, 1- rim, 2- belly plate, 3- hub. DETAILED DESCRIPTION

[0019] 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.

[0020] like Figure 1 As shown, the present invention provides a method for evaluating the assembly performance of a vehicle axle, comprising the following steps: Step S1, the diameter of the wheel hub 3 is The wheel is equivalent to a diameter of Cylinder: , k is the equivalent coefficient; 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.

[0021] The structural rigidity of the wheel is greater than the diameter The stiffness of a cylinder with a diameter less than The stiffness of the cylinder. When calculating the contact stress for the outer diameter of a cylinder, its value will be smaller than the actual value. When contact stress is calculated for the outside diameter of a cylinder, its value will be larger than the actual value.

[0022] The contact stress of the wheel with web structure is equivalent to the calculation diameter of Contact stress of the wheel with a cylindrical structure.

[0023] 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, such as Figure 1 As shown; Step S3, calculate the equivalent coefficient k: , ,i=1,2, In the formula, - wheel aperture; - equivalent diameter; -Poisson's ratio of the contained part (determined by the material of the part); Step S4, using the equivalent cylindrical contact stress calculation formula to determine the contact stress p of the wheel of the web structure: , In the formula, —Interference; E is the elastic modulus; — equivalent diameter; —Contact radius (b= / 2); —Axle bore radius (the axle bore radius is the radius of the center hole of a hollow axle, solid axle =0).

[0024] The contact stress of the wheel calculated by step S4 is a theoretical value. In order to verify the improved algorithm of the contact stress of the wheel-axle interference fit of the web structure, finite element simulation is used for inspection and analysis. In order 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 by finite element technology simulation test analysis.

[0025] The modified formula for calculating the contact stress p of the wheel of the web structure is obtained as follows: , In the formula, —Interference; E—elastic modulus; — equivalent diameter; —Contact radius (b= / 2); —Axle inner diameter radius.

[0026] 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 deriving the oil injection pressure and the counter pressure. Standard TB / T1463 stipulates that the maximum oil injection pressure during the assembly of an integral wheel is: 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 , i.e. 136Mpa; after the wheel axle is assembled, the back pressure test is carried out. The wheel axle shall 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 inspection 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: 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。

[0027] Step S6, comparing the contact stress calculated by 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; When the contact stress calculated by 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 by 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.

[0028] The present invention also provides a method for designing vehicle axle assembly parameters: 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.

[0029] According to the experience of locomotive operation, combined with the transmission torque and the performance of the wheel axle material, the adjustable range of the interference is set to the wheel aperture 1.1-1.3‰ times; according to design experience, the adjustable range of the wheel-axle combination length L is set to 200-250mm.

[0030] 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, the structural stiffness of the wheel is adjusted. When adjusting the structural stiffness of the wheel, the thickness of the web 2 and the thickness of the hub 3 are adjusted first, and then the wheel diameter and the thickness of the rim 1 are adjusted. When the wheel-axle contact stress p is too large, the structural stiffness of the wheel is reduced, and the thickness of the web 2, the thickness of the hub 3, the diameter of the wheel 1 and the thickness of the rim 1 are reduced; when the wheel-axle contact stress p is too small, the structural stiffness of the wheel is increased, and the thickness of the web 2, the thickness of the hub 3, the diameter of the wheel 1 and the thickness of the rim 1 are increased.

[0031] 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.

[0032] 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 evaluating the assembly performance of a vehicle axle, characterized in that: 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: , ,i=1,2, In the formula, - wheel aperture; - equivalent diameter; - Poisson's ratio of the contained part; Step S4, using the equivalent cylindrical contact stress calculation formula to determine the contact stress p of the wheel of the web structure: ， In the formula, —Interference; E—elastic modulus; — equivalent diameter; —Contact radius, b= / 2; —Axle inner diameter radius; Step S5, calculating the limit range of contact stress; Step S6, comparing the contact stress calculated by 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.

2. A method for evaluating vehicle axle assembly performance according to claim 1, characterized in that: When the contact stress calculated by 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 by 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. A method for evaluating the assembly performance of a vehicle axle according to claim 1, characterized in that: 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 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 =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 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。 4. A method for evaluating vehicle axle assembly performance as claimed in claim 1, characterized in that: The correction formula for the wheel contact stress p is: , In the formula, —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: 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. A method for designing vehicle axle assembly parameters as claimed in claim 5, characterized in that: According to the experience of locomotive operation, combined with the transmission torque and the performance of the wheel axle material, the adjustable range of the interference is set to the wheel aperture 1.1-1.3‰ times; according to design experience, the adjustable range of the wheel-axle combination length L is set to 200-250mm.

7. A method for designing vehicle axle assembly parameters as claimed in claim 5, characterized in that: When the wheel-axle contact stress still cannot meet its limit range within the adjustable range of the interference fit and the wheel-axle combination 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. A method for designing vehicle axle assembly parameters as claimed in claim 7, characterized in that: 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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