Method for checking interference fit of pump shaft

Abstract

The present application belongs to the technical field of submersible pumps, and specifically relates to a method for verifying the interference fit of a pump shaft. By loading a first data set, a second data set, and a third data set into a finite element analysis software, the minimum interference and maximum interference of the containing parts and the contained parts during assembly are calculated using the first and second data sets obtained by the finite element analysis software; finally, the third data set obtained by the finite element analysis software is used to verify in turn whether the containing parts and the contained parts meet the requirements under the minimum interference conditions and the maximum interference conditions. In the present application, the containing parts and the contained parts are not simplified, and the third data set includes the data sets of the containing parts and the contained parts under the working load, which is the actual load. Therefore, in the process of design verification, it is more in line with actual needs than the nominal load. The containing parts and the contained parts designed and verified in the present application have higher reliability, and can also achieve the purpose of reducing materials.

Description

Technical Field

[0001] The present application belongs to the technical field of submersible pumps, and specifically relates to a method for verifying the interference fit of a pump shaft. Background Art

[0002] Existing pump shaft designs are typically designed based on the interference fit reserved by engineers' experience, or designed and verified based on simplified thick-walled cylindrical models. The former requires multiple test specimens to determine whether the current design values ​​meet the requirements, and the design cycle is relatively long. In the latter, due to the simplified model, the nominal stress used in the verification can differ significantly from the actual stress. This can lead to reliability issues in the designed structure when faced with complex structural designs and verifications. Furthermore, selecting an excessively large nominal stress can lead to oversized designs, resulting in material waste. Summary of the Invention

[0003] One of the invention purposes of the present application is to provide a method for verifying the interference fit of a pump shaft, which imports the model data of actual including parts and included parts into the finite element analysis software, and verifies in turn through the actual working load whether the including parts and included parts meet the requirements under the minimum interference conditions and the maximum interference conditions, so that the designed including parts and included parts meet the reliability requirements while also achieving the purpose of saving materials.

[0004] According to an embodiment of the present application, a first aspect provides a method for verifying the interference fit of a pump shaft, the method comprising:

[0005] Loading a first data set including model data of the containing component, a second data set including model data of the contained component, and a third data set including working loads of the containing component and the contained component into the finite element analysis software;

[0006] The finite element analysis software obtains the first data set and the second data set and calculates the minimum interference δmin and the maximum interference δmax when the containing part and the contained part are assembled according to a preset formula;

[0007] Analyzing by the finite element analysis software whether the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the minimum interference amount δmin;

[0008] When the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of the minimum interference δmin, the finite element analysis software is used to analyze whether the static strength and fatigue strength of the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of the maximum interference δmax;

[0009] When the containing part and the contained part transmit the working load in the third data set under the maximum interference δmax condition and the working load meets the requirement, the first data set and the second data set that meet the requirement are derived through the finite element analysis software;

[0010] When the included parts and the included parts do not meet the requirements for transmitting the working load in the third data set under the minimum interference δmin condition or the maximum interference δmax condition, the first data set or / and the second data set are corrected according to the preset formula through the finite element analysis software, and are further re-calibrated through the finite element analysis software.

[0011] Furthermore, the first data set includes: the fitting diameter D of the inclusion part, the fitting outer diameter D0 of the inclusion part, the upper dimensional deviation es1 of the inclusion part, the lower dimensional deviation ei1 of the inclusion part, and the surface roughness Ra1 of the inclusion part;

[0012] The second data set includes: the upper dimensional deviation es2 of the contained part, the lower dimensional deviation ei2 of the contained part, the surface roughness Ra2 of the contained part, and the fitting length L of the contained part;

[0013] The third data set includes: at least one of the axial force, radial force, torque, temperature and centrifugal force borne by the containing part and the contained part under working conditions;

[0014] After acquiring the first data set and the second data set, the finite element analysis software calculates the minimum interference δmin and the maximum interference δmax according to the preset formula:

[0015] δmin=ei2-es1-f*(K1*Ra1+k2*Ra2);

[0016] δmax=es2-f*(K1*Ra1+k2*Ra2);

[0017] Where f is the flattening coefficient, K1 and K2 are coefficients respectively.

[0018] Furthermore, analyzing by the finite element analysis software whether the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the minimum interference δmin condition includes:

[0019] Analyze the containing part and the contained part by the finite element analysis software to calculate the contact area S1 of the containing part and the contained part in a bonding state when the containing part and the contained part are under the condition of the minimum interference δmin;

[0020] Analyzing by the finite element analysis software the contact area S2 between the containing part and the contained part in a bonded state when the containing part and the contained part transmit the working load in the third data set under the minimum interference amount δmin condition;

[0021] When the ratio of S2 to S1 is not less than the set threshold, the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the minimum interference amount δmin condition;

[0022] When the ratio of S2 to S1 is less than the set threshold, the containing part and the contained part do not meet the requirements when transmitting the working load in the third data set under the minimum interference amount δmin condition.

[0023] Furthermore, when the containing part and the contained part fail to meet the requirements when transmitting the working load in the third data set under the minimum interference δmin condition, the dimensional lower deviation ei2 of the contained part in the second data set is corrected by the finite element analysis software according to a preset formula to ei2=ei2+δ1, where δ1 is a positive number;

[0024] At the same time, the fitting length L of the included parts in the second data set is corrected to L=L+δ2, where δ2 is a positive number.

[0025] Further, when the inclusion member and the inclusion member fail to meet the requirements for transmitting the working load in the third data set under the maximum interference condition;

[0026] Then the lower deviation ei2 of the size of the included part in the second data set is corrected to ei2=ei2-δ3, where δ3 is a positive number;

[0027] At the same time, the fitting length L of the included parts in the second data set is corrected to L=L+δ4, where δ4 is a positive number.

[0028] Furthermore, when the surface roughness Ra1 of the containing part and the surface roughness Ra2 of the contained part are both in the range of 0.8 to 1.6, the flattening coefficient f has a value range of 0.2 to 0.5;

[0029] When the surface roughness Ra1 of the containing part and the surface roughness Ra2 of the contained part are both in the range of 1.6 to 3.2, the flattening coefficient f is in the range of 0.5 to 1.0;

[0030] The value range of K1 and K2 is 3 to 6;

[0031] The δ1 and the δ3 are positive numbers not less than 0.001, respectively, and the δ2 ​​and the δ4 are positive numbers not less than 0.1, respectively.

[0032] Furthermore, when the containing part and the contained part meet the requirements for transmitting the working load under the maximum interference δmax condition, the finite element analysis method is used to analyze whether the requirements are met under the temperature difference method assembly constraint condition;

[0033] If the requirements are met, exporting the first data set and the second data set that meet the requirements;

[0034] If the requirements are not met, the first data set and / or the second data set are corrected by the finite element analysis software.

[0035] Furthermore, the temperature difference method includes:

[0036] Calculating the assembly temperature T of the contained part using the finite element analysis software; T = T0 + ΔD / (α*D), where T0 is the initial temperature of the contained part before assembly; ΔD is the diameter reduction value of the containing part, ΔD = -1*δmax + Δ0, where Δ0 is the minimum dimensional difference between the containing part and the contained part during assembly;

[0037] Δ0=(-7x10^(-10))*D^3+(4x10^(-7))*D^2-0.0001*D-0.0045;

[0038] The α is the linear expansion coefficient of the contained part;

[0039] When the temperature T is higher than -196° C., the containing component and the contained component meet the assembly requirements. At this time, the first data set and the second data set that meet the requirements are derived through finite element analysis software.

[0040] When the temperature T is lower than -196°C, the containing part and the contained part do not meet the assembly requirements. In this case, the first data set is corrected by the finite element analysis element to:

[0041] The matching diameter D of the inclusion is:

[0042] D=(1+δ5)*D;where δ5 is a constant;

[0043] The outer diameter D0 of the inclusion is:

[0044] D0=(1+δ5)*D0;

[0045] The first data set and the second data set are re-calibrated using the finite element analysis software.

[0046] Furthermore, the range of δ5 is 0.01 to 0.1.

[0047] Furthermore, the temperature difference method further comprises:

[0048] After obtaining the first and second data sets, the finite element analysis software is used to analyze the different depths Ld of the contained part inserted into the liquid nitrogen, where Ld = n*L, n is a positive number, and the depth Ld corresponding to the shrinkage of the contained part closest to ΔD and the shortest time is derived, and the optimal depth value is derived.

[0049] The method for verifying the interference fit of the pump shaft of the present application is to load the first data set, the second data set and the third data set into the finite element analysis software, and then calculate the minimum interference and maximum interference of the containing part and the contained part during assembly using the first data set and the second data set obtained by the finite element analysis software; finally, the third data set obtained by the finite element analysis software is used to verify whether the containing part and the contained part meet the requirements under the minimum interference condition and the maximum interference condition. In the present application, the containing part and the contained part are not simplified, and the third data set includes the data set of the containing part and the contained part under the working load, which is the actual load. Therefore, it is more in line with actual needs in the process of design verification than the nominal load. The containing part and the contained part designed and verified in the present application have higher reliability and can also achieve the purpose of reducing material waste.

[0050] In addition, during the verification process, the present application adopts a scheme of verifying the minimum interference and the maximum interference in sequence. When the minimum interference or the maximum interference does not meet the requirements, the subsequent verification is stopped, and the first data set of the including part and / or the second data set of the included part are corrected to re-calibrate, thereby improving the design verification efficiency of the interference fit. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a flow chart of a method for checking interference fit of a pump shaft in one embodiment of the present application;

[0052] Figure 2 This is a flow chart of a method for checking interference fit of a pump shaft in another embodiment of the present application;

[0053] Figure 3 This is a flow chart of a method for checking interference fit of a pump shaft in another embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0055] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention.

[0056] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented. Any structural modifications, changes in proportional relationships, or adjustments in size should still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0057] Terms such as "upper," "lower," "left," "right," "center," "longitudinal," "transverse," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification to indicate positions or locations are based on those shown in the accompanying drawings and are intended solely for ease of description. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and are therefore not to be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

[0058] like Figure 1 As shown, Figure 1 This is a flow chart of a method for verifying the interference fit of a pump shaft in one embodiment of the present application. It should be noted that the "included part" in this application can be understood as a mounting hole, and the "included part" can be understood as the shaft that fits within the mounting hole. For example, when a pump shaft is designed with a mounting hole, the pump shaft can be understood as the "included part," and the motor shaft that fits within the mounting hole can be understood as the "included part."

[0059] The pump shaft interference fit verification method mentioned in this application can be designed and verified in finite element analysis software in combination with the actual load conditions of the actual containing parts and the contained parts, so as to be as consistent as possible with the actual situation, thereby making the obtained containing parts and the contained parts have higher reliability when connected, and at the same time can achieve the purpose of saving materials. In addition, the verification method in this application verifies the containing parts and the contained parts under the minimum interference amount and the maximum interference amount conditions in turn. When the current verification standard is not met, the subsequent verification is stopped, and the first data set in the containing part and / or the second data set in the contained part are corrected and the verification is restarted, thereby improving the design data efficiency of the containing parts and the contained parts.

[0060] Specifically, the verification method for the pump shaft interference fit includes:

[0061] S110: loading a first data set including model data of the containing component, a second data set including model data of the contained component, and a third data set including working loads of the containing component and the contained component into the finite element analysis software;

[0062] S120: The finite element analysis software obtains the first data set and the second data set and calculates the minimum interference δmin and the maximum interference δmax when the containing part and the contained part are assembled according to a preset formula;

[0063] S130: Analyze using finite element analysis software whether the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of minimum interference δmin;

[0064] S140: When the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of the minimum interference δmin, the finite element analysis software is used to analyze whether the static strength and fatigue strength of the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of the maximum interference δmax;

[0065] S150: When the including part and the included part transmit the working load in the third data set under the condition of the maximum interference δmax and the working load meets the requirements, the first data set and the second data set that meet the requirements are derived through the finite element analysis software;

[0066] S160: When the included parts and the included parts do not meet the requirements for transmitting the working load in the third data set under the minimum interference δmin condition or the maximum interference δmax condition, the first data set or / and the second data set are corrected according to the preset formula through the finite element analysis software, and the finite element analysis software is continued to be re-calibrated.

[0067] In step S110, the model data of the included component included in the first dataset includes at least the dimensional information and material information of the included component. The model data of the contained component included in the second dataset includes at least the dimensional information and material information of the contained component. In other words, the information included in the first dataset is identical to the data of the included component in actual production and application, and the information included in the second dataset is identical to the data of the contained component in actual production and application. In this application, the data of the included and contained components imported into the finite element analysis software is not simplified.

[0068] The third data set includes the loads that the containing part and the contained part need to bear in actual operation. For example, the third data set may include force or moment.

[0069] In step S120, after the finite element analysis software acquires the first and second data sets, it can calculate the minimum interference δmin and maximum interference δmax of the containing part and the contained part during the interference fit based on the containing part model data included in the first data set and the contained part model data included in the second data set. The formula for calculating the minimum interference δmin and the formula for calculating the maximum interference δmax can be directly obtained based on the dimensional deviation of the containing part and the contained part, or can be obtained using a corresponding formula after considering the dimensional deviation and surface quality, such as surface roughness, of the containing part and the contained part.

[0070] In steps S130 to S160, the finite element analysis software is used to determine in turn whether the containing part and the contained part meet the requirements under the minimum interference and maximum interference conditions. Unlike the existing verification method, the present application adopts an iterative optimization scheme, and when the requirements are not met under the minimum interference condition, the subsequent verification is stopped, and the first data set and / or the second data set are corrected to continue searching for the first data set and the second data set that meet the requirements. That is, the present application provides a solution for cyclic iterative optimization by correcting the first data set and / or the second data set. When both the first data set and the second data set meet the minimum interference condition and the maximum interference condition, it means that the current first data set and the second data set meet the requirements.

[0071] It should be noted that the reason for first verifying the load transfer in the third data set under the minimum interference condition in this application is that, under the minimum interference condition, the normal pressure exerted on the mating surface by the containing and contained parts is smaller than under the maximum interference condition. Therefore, the friction force and friction torque generated at the mating surface between the containing and contained parts are relatively small. In other words, if the load in the third data set can be transferred under the minimum interference condition, then the load in the third data set will also be transferred under the maximum interference condition.

[0072] During the maximum interference check, the assembly stress generated by the containing and contained parts under maximum interference is greater than the assembly stress under minimum interference. Therefore, if the static strength and fatigue strength requirements are met during the maximum interference check, the requirements will also be met under minimum interference. Failure to meet static strength requirements can be understood as failure caused by the stress at the assembly point of the containing or contained part exceeding its yield strength. Failure to meet fatigue strength requirements can be understood as failure caused by the containing or contained part being subjected to cyclic stress.

[0073] Furthermore, in one embodiment, the first data set includes: the fitting diameter D of the included part, the fitting outer diameter D0 of the included part, the upper dimensional deviation es1 of the included part, the lower dimensional deviation ei1 of the included part, and the surface roughness Ra1 of the included part.

[0074] The second data set includes: the upper dimensional deviation es2 of the included part, the lower dimensional deviation ei2 of the included part, the surface roughness Ra2 of the included part, and the fitting length L of the included part.

[0075] The third data set includes: at least one of axial force, radial force, torque, temperature and centrifugal force borne by the containing component and the contained component under working conditions.

[0076] After obtaining the first and second data sets, the finite element analysis software calculates the minimum interference δmin and the maximum interference δmax according to the preset formula:

[0077] δmin=ei2-es1-f*(K1*Ra1+k2*Ra2);

[0078] δmax=es2-f*(K1*Ra1+k2*Ra2);

[0079] Where f is the flattening coefficient, K1 and K2 are coefficients respectively.

[0080] In this embodiment, the dimensional deviation and surface roughness of the containing and contained parts are key to calculating the minimum and maximum interferences. In this embodiment, the calculation of the minimum and maximum interferences takes into account not only the dimensional deviation but also the surface roughness of the containing and contained parts.

[0081] Since the surfaces of the containing and contained parts are uneven during the actual production process, and the protruding parts of the surfaces of the containing and contained parts will inevitably be scratched and flattened during interference fit, this reason is taken into account when calculating the minimum and maximum interference fit values, so that the corrected minimum and maximum interference fit values ​​are as close as possible to the actual assembly conditions.

[0082] In one embodiment, see Figure 2 As shown, in the above step S130, when determining whether the minimum interference condition meets the requirements, the following scheme can be used for determination:

[0083] Finite element analysis software is used to analyze whether the containing parts and the contained parts meet the requirements when transmitting the working load in the third data set under the condition of minimum interference δmin, including:

[0084] Finite element analysis software is used to analyze the contact area S1 of the containing part and the contained part in the bonding state when the containing part and the contained part are under the condition of the minimum interference δmin;

[0085] Finite element analysis software is used to analyze the contact area S2 of the containing part and the contained part in a bonding state when the containing part and the contained part transmit the working load in the third data set under the condition of minimum interference δmin;

[0086] When the ratio of S2 to S1 is not less than the set threshold, the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of minimum interference δmin;

[0087] When the ratio of S2 to S1 is less than the set threshold, the containing part and the contained part do not meet the requirements when transmitting the working load in the third data set under the condition of the minimum interference δmin.

[0088] In this embodiment, when judging whether the containing part and the contained part meet the requirements under the minimum interference condition, the scheme adopted is to compare the change in the ratio of the contact area of ​​the containing part and the contained part in the bonding state at the interference fit before and after the third data set load is applied. It should be noted that when the containing part and the contained part transfer the load, the containing part and the contained part will produce relative sliding at the assembly point, and the contact area of ​​the containing part and the contained part in the bonding state will decrease, so S2 will be smaller than the area of ​​S1. If the ratio of the contact area after the load is applied to the contact area when the load is not applied is less than the threshold value, it means that there is a possibility that the containing part and the contained part will loosen after the load is applied, so the ratio of the contact areas can be used to judge whether the minimum interference meets the requirements. The threshold set in this embodiment can be 0.75~1.

[0089] Furthermore, when the including part and the included part do not meet the requirements when transmitting the working load in the third data set under the condition of minimum interference δmin, the finite element analysis software is used to correct the dimensional deviation ei2 of the included part in the second data set according to the preset formula to ei2=ei2+δ1, where δ1 is a positive number; at the same time, the fitting length L of the included part in the second data set is corrected to L=L+δ2, where δ2 is a positive number.

[0090] In this embodiment, when the minimum interference condition does not meet the requirements, it is provided that the lower deviation of the included part and the fitting length of the included part can be corrected. The reason for correcting these two parameters is that when the minimum interference condition does not meet the requirements, the main reason is that the containing part and the included part do not meet the requirements when transmitting torque or axial force. Although increasing the fitting diameter D of the containing part can also be used to try to iteratively solve the problem, the fitting diameter D is the minimum size that meets the requirements after calculation. If this value is increased, the size of the containing part and the included part will increase, which is not in line with the principle of material conservation. For this reason, this embodiment adopts the method of increasing the lower deviation of the size of the included part and increasing the fitting length of the included part, so that the friction and friction torque of the containing part and the included part at the assembly point are increased, thereby meeting the requirements when transmitting torque or axial force.

[0091] It should be noted that δ1 and δ2 in this application can be understood as the step size of the correction during iteration. For example, δ1 can be any value between 0.001 and 0.1, and is of course not limited to this. δ2 can be any value between 0.1 and 10, and is of course not limited to this. In addition, δ1 and δ2 are not limited to fixed values ​​during the iteration process; for example, in the early iterations, δ1 and δ2 values ​​can be selected to be larger values, and in the later iterations, δ1 and δ2 can be converted to smaller values. When the number of iterations is less than N1, δ1 can be a constant C11, and δ2 can be a constant C21; when the number of iterations is greater than or equal to N1 and less than N2, δ1 can be a constant C12, and δ2 can be a constant C22, where C11 is not less than C12, and C21 is not less than C22. In this way, the first and second data sets that meet the requirements can be obtained through iteration more quickly.

[0092] In one embodiment, in the above step S140, whether the requirements are met under the maximum interference condition can be determined by the following steps:

[0093] When the working load transmitted between the included parts under the condition of maximum interference does not meet the requirements, the dimensional deviation ei2 of the included parts in the second data set is corrected to ei2=ei2-δ3, where δ3 is a positive number; at the same time, the fitting length L of the included parts in the second data set is corrected to L=L+δ4, where δ4 is a positive number.

[0094] In this embodiment, when the maximum interference fit between the containing member and the contained member does not meet the requirements, the stress between the containing member and the contained member can be reduced to meet the requirements. To achieve this, the dimensional deviation of the contained member can be reduced. If the dimensional deviation of the contained member is reduced, the load transfer capacity between the containing member and the contained member is reduced if the mating length of the contained member is not changed. To achieve this, the mating length of the contained member needs to be increased.

[0095] In one embodiment, based on the actual interference fit of the containing part and the contained part, parameter selections for calculating the minimum and maximum interference fits under different surface quality conditions of the containing part and the contained part are also listed. These optional parameters can make the calculation of the minimum and maximum interference fits of the containing part and the contained part more consistent with actual conditions, thereby enabling the optimization results to be applied in practice. Specifically, when the surface roughness Ra1 of the containing part and the surface roughness Ra2 of the contained part are both in the range of 0.8 to 1.6, the flattening coefficient f has a value range of 0.2 to 0.5; when the surface roughness Ra1 of the containing part and the surface roughness Ra2 of the contained part are both in the range of 1.6 to 3.2, the flattening coefficient f has a value range of 0.5 to 1.0; the value range of K1 and K2 is 3 to 6; δ1 and δ3 are positive numbers not less than 0.001, and δ2 and δ4 are positive numbers not less than 0.1.

[0096] In one embodiment, see Figure 3 As shown, when the including part and the included part meet the requirements for transmitting the working load under the maximum interference δmax condition, the finite element analysis method is used to analyze whether the requirements are met under the assembly constraint conditions of the temperature difference method; if the requirements are met, the first data set and the second data set that meet the requirements are derived;

[0097] If the requirements are not met, the first data set and / or the second data set are corrected using finite element analysis software.

[0098] After the minimum and maximum interference fits of the including and included parts are determined, during the actual installation process, it is also necessary to consider the impact of the assembly temperature on the dimensions of the including and included parts. If the current dimensions do not meet the requirements, the first data set of the including part and the second data set of the included part need to be corrected.

[0099] Furthermore, in one embodiment, the temperature difference method includes:

[0100] Calculate the temperature T of the included parts assembly using finite element analysis software;

[0101] T = T0 + ΔD / (α*D), where T0 is the initial temperature of the contained part before assembly; ΔD is the diameter reduction value of the contained part, ΔD = -1*δmax + Δ0, where Δ0 is the minimum dimensional difference between the containing part and the contained part during assembly;

[0102] Δ0=(-7x10^(-10))*D^3+(4x10^(-7))*D^2-0.0001*D-0.0045;

[0103] α is the linear expansion coefficient of the contained part;

[0104] When T is higher than -196°C, the containing part and the contained part meet the assembly requirements. At this time, the first data set and the second data set that meet the requirements are derived through the finite element analysis software;

[0105] When T is lower than -196°C, the containing part and the contained part do not meet the assembly requirements. At this time, the first data set is corrected by the finite element analysis element as follows:

[0106] The matching diameter D of the included parts is:

[0107] D=(1+δ5)*D;where δ5 is a constant;

[0108] The outer diameter D0 of the included part is:

[0109] D0=(1+δ5)*D0;

[0110] The first and second data sets were recalibrated using finite element analysis software.

[0111] In this embodiment, if the assembly temperature T calculated by the finite element analysis software is higher than -196°C, it indicates that the contained component can be cooled by liquid nitrogen, and the minimum temperature for liquid nitrogen cooling is -196°C. If the temperature difference method does not meet the requirements, the above-mentioned temperature difference method shows that increasing the mating diameter D of the contained component can correspondingly reduce the assembly temperature T. Here, δ5 ranges from 0.01 to 0.1.

[0112] Furthermore, the temperature difference method also includes:

[0113] After obtaining the first and second data sets, the finite element analysis software is used to analyze the different depths L of the included part inserted into the liquid nitrogen. d When L d =n*L, n is a positive number, the depth L corresponding to the shrinkage of the contained part closest to ΔD and the shortest time d , and derive the optimal depth value.

[0114] In this embodiment, the amount of contraction of the contained part varies when the contained part is inserted into liquid nitrogen at different lengths. Therefore, in this application, simulation analysis is performed in finite element analysis software to obtain the optimal depth value of the contained part when inserted into liquid nitrogen for cooling.

[0115] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0116] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for checking the interference fit of a pump shaft, characterized in that: The verification method comprises: A first data set including model data of an including component, a second data set including model data of a contained component, and a third data set including operating loads of the including component and the contained component are loaded into finite element analysis software; the including component is a component having an assembly hole, and the contained component is a shaft that fits into the assembly hole; After acquiring the first data set and the second data set, the finite element analysis software calculates the minimum interference δmin and the maximum interference δmax when the containing part and the contained part are assembled according to a preset formula; Analyzing by the finite element analysis software whether the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the minimum interference amount δmin; When the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of the minimum interference δmin, the finite element analysis software is used to analyze whether the static strength and fatigue strength of the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the condition of the maximum interference δmax; When the containing part and the contained part transmit the working load in the third data set under the maximum interference δmax condition and the working load meets the requirement, the first data set and the second data set that meet the requirement are derived through the finite element analysis software; When the included parts and the included parts do not meet the requirements for transmitting the working load in the third data set under the minimum interference δmin condition or the maximum interference δmax condition, the first data set or / and the second data set are corrected according to the preset formula through the finite element analysis software, and are further re-calibrated through the finite element analysis software.

2. The method for checking the interference fit of a pump shaft according to claim 1, characterized in that: The first data set includes: the fitting diameter D of the inclusion part, the fitting outer diameter D0 of the inclusion part, the upper dimensional deviation es1 of the inclusion part, the lower dimensional deviation ei 1 of the inclusion part, and the surface roughness Ra1 of the inclusion part; The second data set includes: the upper dimensional deviation es2 of the contained part, the lower dimensional deviation ei 2 of the contained part, the surface roughness Ra2 of the contained part, and the fitting length L of the contained part; The third data set includes: at least one of the axial force, radial force, torque, temperature and centrifugal force borne by the containing part and the contained part under working conditions; After acquiring the first data set and the second data set, the finite element analysis software calculates the minimum interference δmin and the maximum interference δmax according to the preset formula: δmin=ei 2-es1-f*(K1*Ra1+k2*Ra2); δmax=es2-f*(K1*Ra1+k2*Ra2); Where f is the flattening coefficient, K1 and K2 are coefficients respectively.

3. The method for checking the interference fit of a pump shaft according to claim 2, characterized in that: Analyzing by the finite element analysis software whether the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the minimum interference amount δmin includes: Analyze the containing part and the contained part by the finite element analysis software to calculate the contact area S1 of the containing part and the contained part in a bonding state when the containing part and the contained part are under the condition of the minimum interference δmin; Analyzing by the finite element analysis software the contact area S2 between the containing part and the contained part in a bonded state when the containing part and the contained part transmit the working load in the third data set under the minimum interference amount δmin condition; When the ratio of S2 to S1 is not less than the set threshold, the containing part and the contained part meet the requirements when transmitting the working load in the third data set under the minimum interference amount δmin condition; When the ratio of S2 to S1 is less than the set threshold, the containing part and the contained part do not meet the requirements when transmitting the working load in the third data set under the minimum interference amount δmin condition.

4. The method for checking the interference fit of a pump shaft according to claim 3, characterized in that: When the containing part and the contained part fail to meet the requirements when transmitting the working load in the third data set under the minimum interference δmin condition, the dimensional lower deviation ei 2 of the contained part in the second data set is corrected by the finite element analysis software according to a preset formula to be ei 2=ei 2+δ1, where δ1 is a positive number; At the same time, the fitting length L of the included parts in the second data set is corrected to L=L+δ2, where δ2 is a positive number.

5. The method for checking the interference fit of a pump shaft according to claim 4, characterized in that: When the inclusion part and the inclusion part fail to meet the requirements for transmitting the working load in the third data set under the maximum interference condition; Then the lower deviation ei 2 of the size of the included part in the second data set is corrected to ei 2=ei 2-δ3, where δ3 is a positive number; At the same time, the fitting length L of the included parts in the second data set is corrected to L=L+δ4, where δ4 is a positive number.

6. The method for checking the interference fit of a pump shaft according to claim 5, characterized in that: When the surface roughness Ra1 of the containing part and the surface roughness Ra2 of the contained part are both in the range of 0.8 to 1.6, the flattening coefficient f is in the range of 0.2 to 0.5; When the surface roughness Ra1 of the containing part and the surface roughness Ra2 of the contained part are both in the range of 1.6 to 3.2, the flattening coefficient f is in the range of 0.5 to 1.0; The value range of K1 and K2 is 3 to 6; The δ1 and the δ3 are positive numbers not less than 0.001, respectively, and the δ2 ​​and the δ4 are positive numbers not less than 0.1, respectively.

7. The method for checking the interference fit of a pump shaft according to claim 2, characterized in that: When the containing part and the contained part meet the requirements for transmitting the working load under the maximum interference δmax condition, the finite element analysis method is used to analyze whether the requirements are met under the temperature difference method assembly constraint condition; If the requirements are met, exporting the first data set and the second data set that meet the requirements; If the requirements are not met, the first data set and / or the second data set are corrected by the finite element analysis software.

8. The method for checking the interference fit of a pump shaft according to claim 7, characterized in that: The temperature difference method includes: Calculating the temperature T of the included component assembly by the finite element analysis software; T = T0 + ΔD / (α*D), where T0 is the initial temperature of the contained part before assembly; ΔD is the diameter reduction value of the contained part, ΔD = -1*δmax + Δ0, where Δ0 is the minimum dimensional difference between the containing part and the contained part during assembly; Δ0=(-7x10^(-10))*D^3+(4x10^(-7))*D^2-0.0001*D-0.0045; The α is the linear expansion coefficient of the contained part; When the temperature T is higher than -196° C., the containing component and the contained component meet the assembly requirements. At this time, the first data set and the second data set that meet the requirements are derived through finite element analysis software. When the temperature T is lower than -196°C, the containing part and the contained part do not meet the assembly requirements. In this case, the first data set is corrected by the finite element analysis element to: The matching diameter D of the inclusion is: D=(1+δ5)*D;where δ5 is a constant; The outer diameter D0 of the inclusion is: D0=(1+δ5)*D0; The first data set and the second data set are re-calibrated using the finite element analysis software.

9. The method for checking the interference fit of a pump shaft according to claim 8, characterized in that: The range of δ5 is 0.01 to 0.

1.

10. The method for checking the interference fit of a pump shaft according to claim 8, characterized in that: The temperature difference method also includes: After obtaining the first data set and the second data set, the finite element analysis software is used to analyze the different depths L of the contained part inserted into the liquid nitrogen. d When L d =n*L, n is a positive number, the depth L corresponding to the shrinkage of the contained part closest to ΔD and the shortest time d , and derive the optimal depth value.

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