Method and device for determining magnitude of interference of multistage assembly components

Abstract

The embodiment of the invention provides a method and device for determining the interference magnitude of a multi-stage assembly component, and the method comprises the steps: determining the yield stress of materials of at least two interference fit parts, and determining the target stress data of the parts based on the yield stress; wherein the component comprises at least two interference fit parts; threshold interference magnitude data of the two interference fit parts are determined, simulation is carried out based on the threshold interference magnitude data, and the stress distribution condition is determined; determining initial stress data based on the stress distribution condition and the storage condition; and determining an interference magnitude range based on the initial stress data and the target stress data. By means of the scheme, it is ensured that even after long-term storage, interference fit of the components can still be kept within the range required by design, and the stability and reliability of equipment are improved.

Description

Technical Field

[0001] The embodiments of this specification relate to the technical field of component assembly, and particularly to a method for determining the interference amount of multi-stage assembly components. Background Art

[0002] After the production and installation of the armature assembly, it usually needs to be stored for a long time, and the equipment accuracy in the long-term storage state needs to be ensured. However, some materials of the armature assembly may undergo room temperature creep under the long-term stress of interference fit, resulting in a reduction in the internal stress of the armature assembly. Therefore, there is a risk that the interference fit stress of the armature assembly will slowly decrease below the lower limit of the interference fit standard under storage conditions, which may affect its accuracy.

[0003] In the mating relationships of the various parts in the armature assembly, there are three groups of interference fits between the feedback rod and the baffle, between the baffle and the spring tube, and between the baffle and the armature. The magnitudes of the interference amounts of these three groups of interference fits greatly affect the mating tightness of the various parts in the armature assembly, which is crucial for ensuring the stability and response speed of the assembly.

[0004] The interference amount not only has an important impact on the assembly and performance of the armature assembly, but also, as the core component of the electro-hydraulic servo valve, the quality of its performance is directly related to the stability and control effect of the entire electro-hydraulic servo system. An appropriate interference amount can ensure that the parts in the armature assembly are firmly fixed after assembly, reducing looseness and friction, which is very crucial for the precise control of the armature assembly. At the same time, the interference amount is also related to the sealing performance and fatigue resistance between parts. An appropriate interference amount can improve these performances and extend the service life of the assembly, which is very important for the long-term stable operation of the electro-hydraulic servo valve. However, an excessive interference amount will cause the stress on the parts to exceed the yield strength, thereby causing a certain degree of damage to the parts.

[0005] Most of the existing research considers the interference amount range from the perspective of assembly, but lacks the consideration of the interference amount of multi-stage assembly from the perspective of service life, and thus fails to solve the problem of the reduction of the pre-tightening force of multi-stage components during long-term storage.

[0006] In multi-stage assembly components, stress relaxation may occur when the components are placed at room temperature for a long time, which may lead to insufficient pre-tightening force. Therefore, it is also necessary to predict the reliability of the components. However, most of the current research does not consider whether the pre-tightening force of the components meets the requirements after long-term storage, and lacks an interference amount optimization control method considering the stress relaxation characteristics during long-term storage. Thus, a better solution is urgently needed. Summary of the Invention

[0007] In view of this, the embodiments of the present specification provide a method for determining the interference amount of a multi-level assembly component. One or more embodiments of the present specification are also related to a device for determining the interference amount of a multi-level assembly component, a computing device, a computer-readable storage medium, and a computer program, so as to solve the technical defects existing in the prior art.

[0008] According to the first aspect of the embodiments of the present specification, there is provided a method for determining the interference amount of a multi-level assembly component, including:

[0009] Determine the yield stress of the materials of at least two interference-fitting parts, and determine the target stress data of the component based on the yield stress; wherein, the component includes at least two interference-fitting parts;

[0010] Determine the threshold interference amount data of at least two interference-fitting parts, and perform simulation based on the threshold interference amount data to determine the stress distribution;

[0011] Determine the initial stress data based on the stress distribution and the storage conditions;

[0012] Determine the interference amount based on the initial stress data and the target stress data.

[0013] In a possible implementation manner, determining the target stress data of the component based on the yield stress includes:

[0014] Determine the relevant interference amount between each part based on the assembly relationship of at least two interference-fitting parts;

[0015] Sort the relevant interference amounts from small to large to determine the sorting result;

[0016] Select the first interference amount in the sorting result as the target stress data.

[0017] In a possible implementation manner, performing simulation based on the threshold interference amount data to determine the stress distribution includes:

[0018] Determine the models of at least two interference-fitting parts, and determine the attribute information of the models;

[0019] Perform assembly based on the models and the attribute information to determine the initial component model;

[0020] Perform interaction simulation based on the initial component model and the threshold interference amount data to determine the stress distribution.

[0021] In a possible implementation manner, performing interaction simulation based on the initial component model and the threshold interference amount data to determine the stress distribution includes:

[0022] Add contact attributes and interaction parameters to the initial component model to determine the target component model;

[0023] Perform finite element simulation based on the target component model and the threshold interference amount data to determine the stress distribution.

[0024] In one possible implementation, determine the initial stress data based on the stress distribution and the storage conditions, including:

[0025] Extract the target stress based on the stress distribution;

[0026] Determine the initial stress data based on the target stress and the storage conditions.

[0027] In one possible implementation, determine the initial stress data based on the target stress and the storage conditions, including:

[0028] Conduct a creep test based on the target stress and the storage conditions to determine the relaxation rate;

[0029] Determine the initial stress data based on the relaxation rate.

[0030] In one possible implementation, determine the interference amount based on the initial stress data and the target stress data, including:

[0031] Determine the storage stress data from the initial stress data and the target stress data;

[0032] Determine the interference amount based on the storage stress data.

[0033] According to the second aspect of the embodiments of this specification, there is provided a device for determining the interference amount of a multi-stage assembly component, including:

[0034] A target stress determination module, configured to determine the yield stress of the part material and determine the target stress data of the component based on the yield stress; wherein, the component includes at least two interference-fitted parts;

[0035] A stress distribution determination module, configured to determine the threshold interference amount data of at least two interference-fitted parts, perform simulation based on the threshold interference amount data, and determine the stress distribution;

[0036] An initial stress determination module, configured to determine the initial stress data based on the stress distribution and the storage conditions;

[0037] An interference amount determination module, configured to determine the interference amount based on the initial stress data and the target stress data.

[0038] According to the third aspect of the embodiments of this specification, there is provided a computing device, including:

[0039] A memory and a processor;

[0040] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the above-mentioned method for determining the interference amount of the multi-stage assembly components are implemented.

[0041] According to the fourth aspect of the embodiments of the present specification, a computer-readable storage medium is provided, which stores computer-executable instructions. When the instructions are executed by a processor, the steps of the above-mentioned method for determining the interference amount of the multi-stage assembly components are implemented.

[0042] According to the fifth aspect of the embodiments of the present specification, a computer program is provided. When the computer program is executed on a computer, the computer is made to execute the steps of the above-mentioned method for determining the interference amount of the multi-stage assembly components.

[0043] The embodiments of the present specification provide a method and device for determining the interference amount of multi-stage assembly components. The method for determining the interference amount of multi-stage assembly components includes: determining the yield stress of the materials of at least two interference-fit parts, and determining the target stress data of the component based on the yield stress; wherein, the component includes at least two interference-fit parts; determining the threshold interference amount data of the two interference-fit parts, and performing simulation based on the threshold interference amount data to determine the stress distribution; determining the initial stress data based on the stress distribution and the storage conditions; and determining the interference amount range based on the initial stress data and the target stress data. Through the above solutions, it is ensured that even after long-term storage, the interference fit of the component can still be maintained within the designed requirements range, improving the stability and reliability of the equipment. Description of the Drawings

[0044] Figure 1 is a flowchart of a method for determining the interference amount of multi-stage assembly components provided by an embodiment of the present specification;

[0045] Figure 2 is a schematic diagram of a thick-walled cylinder of a method for determining the interference amount of multi-stage assembly components provided by an embodiment of the present specification;

[0046] Figure 3 is a schematic diagram of a unit body of a method for determining the interference amount of multi-stage assembly components provided by an embodiment of the present specification;

[0047] Figure 4 is a schematic diagram of the radial stress of a method for determining the interference amount of multi-stage assembly components provided by an embodiment of the present specification;

[0048] Figure 5 is a schematic diagram of the parts of an armature assembly of a method for determining the interference amount of multi-stage assembly components provided by an embodiment of the present specification;

[0049] Figure 6It is a schematic diagram of the original model of the armature assembly in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0050] Figure 7 It is a cross-sectional view of the armature assembly before interference fitting in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0051] Figure 8 It is a stress nephogram of the feedback rod in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0052] Figure 9 It is a stress nephogram of the baffle in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0053] Figure 10 It is a stress nephogram of the bellows in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0054] Figure 11 It is a stress nephogram of the armature in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0055] Figure 12 It is a linear fitting diagram between the strain growth rate and the logarithm of time at different temperatures in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0056] Figure 13 It is a linear fitting diagram between the parameter C and the logarithm of time lnt at different temperatures in a method for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0057] Figure 14 It is a schematic structural diagram of a device for determining the interference amount of a multi-stage assembly component provided by an embodiment of this specification;

[0058] Figure 15 It is a structural block diagram of a computing device provided by an embodiment of this specification. Detailed implementation manners

[0059] In the following description, many specific details are set forth in order to provide a thorough understanding of this specification. However, this specification can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of this specification. Therefore, this specification is not limited by the specific implementations disclosed below.

[0060] The terms used in one or more embodiments of this specification are for the purpose of describing specific embodiments only and are not intended to limit one or more embodiments of this specification. The singular forms "a" and "the" used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" used in one or more embodiments of this specification refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0061] It should be understood that although the terms first, second, etc. may be used in one or more embodiments of this specification to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of one or more embodiments of this specification, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0062] In this specification, a method for determining the interference amount of a multi-stage assembly component is provided. This specification also relates to a device for determining the interference amount of a multi-stage assembly component, a computing device, and a computer-readable storage medium, which will be described in detail one by one in the following embodiments.

[0063] See Figure 1 , Figure 1 which shows a flowchart of a method for determining the interference amount of a multi-stage assembly component provided according to an embodiment of this specification, specifically including the following steps.

[0064] Step 101: Determine the yield stress of the materials of at least two interference-fit parts, and determine the target stress data of the component based on the yield stress; wherein, the component includes at least two interference-fit parts.

[0065] Among them, the target stress data can be used to calculate the data of the maximum interference amount of the component, that is, the interference amount at which any part in the component does not undergo plastic deformation. The component can be a component obtained by combining at least two interference-fit parts. For example, the component is an armature assembly. Correspondingly, the interference-fit parts can include a feedback rod, a baffle, a spring tube, and an armature.

[0066] In a possible implementation manner, determining the target stress data of the component based on the yield stress includes: determining the relevant interference amounts between the parts based on the assembly relationship of at least two interference-fit parts; sorting the relevant interference amounts from small to large to determine the sorting result; and selecting the first interference amount of the sorting result as the target stress data.

[0067] Among them, the relevant interference amount is the maximum interference amount selected for each part after assembly.

[0068] In practical applications, the maximum interference amount of each interference relationship can be determined through the thick-walled cylinder theory according to the principle that the stress on the materials of each part should not exceed the corresponding yield stress of each material.

[0069] For multi-layer interference fits, the middle part is subjected to internal and external pressures, such as p 0 and p are the internal and external contact surface stresses of the cylinder respectively, and R 1 and R 2 are the inner radius and outer radius of the cylinder respectively. Similarly, for the calculation of the interference fit parameters of the armature assembly, the key geometric data of each component can be extracted and abstracted as a thick-walled cylinder subjected to internal and external pressures for calculation. The thick-walled cylinder theory comprehensively considers geometric relationships, static relationships, and physical relationships.

[0070] Figure 2 represents a thick-walled cylinder, and p 1 and p 2 are the internal pressure and external pressure of the cylinder respectively. Taking two adjacent cylindrical surfaces with radii ρ and ρ + dρ and two adjacent radial surfaces with an included angle of , a unit body abcd is taken out from the cylinder, and the dimension of the unit body along the axis direction (i.e., the dimension perpendicular to the drawing plane) is set to one unit.

[0071] Furthermore, the unit body is enlarged as shown in Figure 3 . Since the deformation is symmetric about the axis of the cylinder, the displacement u of each point in the cylinder along the radial direction is related to the radius ρ. After deformation, the ad side of the unit body is displaced to a'd ', and the circumferential strain is obtained as follows:

[0072]

[0073] Because the displacement u is a function of ρ, on the ab side, if the radial displacement at point a is u, then the radial displacement at point b should be u + du. The radial strain at point a is:

[0074]

[0075] The normal stress σ ρ acting on the cylindrical surface ad of the unit body, as shown in Figure 4 , is called the radial stress, and the normal stress acting on the radial surface ab is called the circumferential stress or hoop stress. According to the property of axisymmetry, both σ ρ and are only functions of ρ and are independent of the angle. Therefore, the normal stresses on the cd and ab surfaces are the same, and the normal stress on the bc surface is one increment dσ more than that on the ab surface.ρ Due to the axisymmetry, there is no shear stress on the four surrounding faces of the element, so σ ρ and are both principal stresses. Projecting the internal forces acting on the element onto the coordinate ρ direction, we get:

[0076] After arranging the above formula and neglecting the higher-order infinitesimals, we get:

[0077]

[0078] In the case of linear elasticity, from the generalized Hooke's law, the relationship between stress and strain is obtained:

[0079]

[0080] In the formula, E is the Young's modulus of the material, and μ is the Poisson's ratio of the material.

[0081] Based on the relationships in the above three aspects, the stress and deformation of the thick-walled cylinder can be further obtained. Substituting Eqs. (1) and (2) into Eqs. (4) and (5), we get:

[0082]

[0083] From this, σ ρ and are obtained as:

[0084]

[0085] Substituting σ ρ and in the above formula into the equilibrium equation (3), after arrangement, we get:

[0086]

[0087] This is the equilibrium equation expressed in terms of the displacement u. When solving the above differential equation, let ρ = e t , that is, lnρ = t, then the differential equation (10) is transformed into:

[0088] From this, the general solution of the displacement u is obtained as:

[0089]

[0090] In the formula, A and B are integration constants.

[0091] Substituting the displacement u into (8) and (9), the stress is obtained:

[0092]

[0093] The boundary conditions for determining the integration constants are: when ρ = a, σρ = -p 1 ; when ρ = b, σ ρ = -p 2

[0094] Substitute them into (12) respectively, and we get:

[0095]

[0096] Solve from the above two equations:

[0097]

[0098] Substitute the constants A and B back into equations (16) and (17) to obtain the expression of stress:

[0099]

[0100] Equations (18) and (19) show that σ ρ and are constants. According to the generalized Hooke's law, the strain ε Z in the axial direction is also a constant and has nothing to do with ρ. Therefore, the cross-section before deformation remains a plane after deformation.

[0101] Substitute the integration constants in equations (16) and (17) into equation (11) to find the radial displacement of any point in the cylinder wall as:

[0102]

[0103] Above, equations (18), (19), and (20) are the theoretical formulas for thick-walled cylinders. The calculation will be illustrated in combination with the armature assembly.

[0104] The theoretical formulas for thick-walled cylinders are as follows:

[0105]

[0106] Among them, σ r is the radial stress, σ θ is the circumferential stress, σ is the total stress, r is the radius of the cylinder, R 1 and R 2 are the minor diameter and major diameter of the cylinder respectively, E is the elastic modulus, μ is the Poisson's ratio, and u is the radial displacement.

[0107] When analyzing the interference fit value range of the armature assembly, according to the assembly relationship of each part, the armature assembly is divided into two parts: the interference fit of armature + baffle + feedback rod and the interference fit of spring tube + baffle + feedback rod for separate analysis.

[0108] In this case, p 1 is the stress between the feedback rod and the baffle, p 2is the stress between the baffle and the armature. Let r 1 be the radius of the feedback rod, r 2 be the outer diameter of the contact position between the upper end of the baffle and the armature, r 3 be the outer diameter of the armature.

[0109] First, using the fact that the stress inside the armature is less than the yield strength of the armature material 1J50, that is, the maximum value of the stress inside the armature is its yield strength, p 2 maximum value can be calculated. At this time, R 1 = r 2 , R 2 = r 3 , r = r 2 , σ < σ 1J50 , p 2 The expression for the maximum value is:

[0110]

[0111] Then, using the fact that the stress outside the feedback rod is less than the yield strength of the feedback rod material 3J21, that is, the maximum value of the stress outside the feedback rod is its yield strength, p 1 maximum value can be calculated. At this time, R 1 = 0, R 2 = r 1 , r = r 1 , σ < σ 3J21 . p 1 The expression for the maximum value is:

[0112] p 1max1 = σ 3J21 (23)

[0113] As the value of p1 decreases, the stress inside the baffle will decrease, and the decrease of p2 will increase the circumferential stress inside the baffle. Therefore, keeping p2 at the maximum value unchanged and changing p1, make the maximum value of the stress inside the baffle be the yield strength of the baffle material 3J1.

[0114] The stress inside the baffle. At this time, R 1 = r 1 , R 2 = r 2 , r = r 1 , p 2 = p 2max , and the calculation is:

[0115]

[0116] p 1 The second maximum value p 1max2 , take the minimum value between p 1max1 and p 1max2 as p1max .

[0117] Let p 1 = p 1max , p 2 = p 2max . Substitute into the calculation formula of u to solve the displacements of each part.

[0118] When R 1 = r 2 , R 2 = r 3 , r = r 2 , E = E 1J50 , the displacement u 3in of the inner side of the armature can be obtained.

[0119] When R 1 = r 1 , R 2 = r 2 , r = r 2 , E = E 3J1 , the displacement u 2out of the outer side of the baffle can be obtained.

[0120] When R 1 = r 1 , R 2 = r 2 , r = r 1 , E = E 3J1 , the displacement u 2in of the inner side of the baffle can be obtained.

[0121] When R 1 = 0, R 2 = r 1 , r = r 1 , E = E 3J21 , the displacement u 1out of the outer side of the feedback rod can be obtained.

[0122] The interference amount between the baffle and the armature is:[[]]

[0123] Iter1 = 2×(u 3in - u 2out )(25)[[]]

[0124] The interference amount between the feedback rod and the baffle is:[[]]

[0125] Iter2 = 2×(u 2in - u 1out )(26)[[]]

[0126] Similarly, just change different R 1 , R 2 , r, E. The calculation process is the same.

[0127] In this case, p 1 is the stress between the feedback rod and the baffle, and p 2 is the stress between the baffle and the bourdon tube. Let r 11 be the radius of the feedback rod, r 21 be the outer diameter at the contact position between the lower end of the baffle and the bourdon tube, and r 31 be the outer diameter of the bourdon tube.

[0128] First, since the stress inside the bourdon tube is less than the yield strength of the bourdon tube material QBe1.9, that is, the maximum value of the stress inside the bourdon tube is its yield strength, p 2 maximum value can be calculated from this. At this time, R 1 = r 21 , R 2 = r 31 , r = r 21 , σ < σ QBe1.9 , and p 2 maximum value can be solved:

[0129]

[0130] Then, since the stress outside the feedback rod is less than the yield strength of the feedback rod material 3J21, that is, the maximum value of the stress outside the feedback rod is its yield strength, p 1 maximum value can be calculated inversely from this. At this time, R 1 = 0, R 2 = r 11 , r = r 11 , σ < σ 3J21 , and p 1 maximum value can be solved:

[0131] p 1max1 = σ 3J21 (28)

[0132] As the value of p1 decreases, the stress inside the baffle will decrease, and the decrease of p2 will increase the circumferential stress inside the baffle. Therefore, keeping p2 at the maximum value unchanged and changing p1, make the maximum value of the stress inside the baffle be the yield strength of the baffle material 3J1.

[0133] The stress inside the baffle. At this time, R 1 = r 11 , R 2 = r 21 , r = r 11 , p 2 = p 2max , and the calculation is:

[0134]

[0135] Solve p 1The second maximum value p 1max2 , take p 1max1 and p 1max2 The minimum value between them is p 1max .

[0136] Let p 1 = p 1max , p 2 = p 2max , substitute into the calculation formula of u to solve the displacements of each part.

[0137] When R 1 = r 21 , R 2 = r 31 , r = r 21 , E = E QBe1.9 , the inner displacement u of the bourdon tube can be obtained 31in .

[0138] When R 1 = r 11 , R 2 = r 21 , r = r 21 , E = E 3J1 , the outer displacement u of the baffle can be obtained 21out .

[0139] When R 1 = r 11 , R 2 = r 21 , r = r 11 , E = E 3J1 , the inner displacement u of the baffle can be obtained 21in .

[0140] When R 1 = 0, R 2 = r 11 , r = r 11 , E = E 3J21 , the outer displacement u of the feedback rod can be obtained 11out .

[0141] The interference between the baffle and the bourdon tube is:

[0142] Iter3 = 2×(u 31in - u 21out )(30)

[0143] The interference between the feedback rod and the baffle is:

[0144] Iter21 = 2×(u 21in - u 11out )(31)

[0145] Combined with the interference amount between the obtained feedback rod and the baffle, its final value is the minimum value between Iter2 and Iter21. That is:

[0146] Iter2 = min(Iter2,Iter21)(32)

[0147] That is, the target stress data is the minimum value between Iter2 and Iter21.

[0148] Step 102: Determine the threshold interference amount data of at least two interference fit parts, and perform simulation based on the threshold interference amount data to determine the stress distribution.

[0149] Among them, the threshold interference amount data can be the minimum interference amount, and the minimum interference amount can be determined according to the material-related standards of the parts.

[0150] In practical applications, in order to ensure the tight fit of the parts in the armature assembly after long-term storage, reduce looseness and friction, and ensure the stability and response speed of the assembly, it is necessary to determine the minimum interference amount of each interference fit relationship in the armature assembly according to the national standard. The interference amount of the parts in the assembly after long-term stress relaxation should meet the requirement of not less than the minimum interference amount. The stress magnitude corresponding to the minimum interference amount is calculated by finite element simulation.

[0151] In a possible implementation manner, performing simulation based on the threshold interference amount data to determine the stress distribution includes: determining the models of at least two interference fit parts, and determining the attribute information of the models; performing assembly based on the models and the attribute information to determine the initial component model; performing interaction simulation based on the initial component model and the threshold interference amount data to determine the stress distribution.

[0152] Among them, the attribute information includes material information, assembly relationship, and assembly sequence.

[0153] In practical applications, the descriptions of the parts of the armature assembly are as Figure 5 shown. Before the simulation process, import the 3D model into the Abaqus software, as Figure 6 shown. Since the wing-shaped structures at both ends of the armature model are far from the mating part and have little influence on the simulation results, the structure can be simplified, and the specific simplification method is not limited in the embodiments of this specification.

[0154] It should be noted that before the simulation process, the 3D model can be imported into other finite element software, and this specification does not limit the finite element software.

[0155] Furthermore, according to the given material information, create materials in the Abaqus software and assign them to the corresponding parts. According to the assembly relationship and assembly sequence determined in the process assembly flow, place the parts at the interference fit preparation positions, asFigure 7 as shown, which is the initial component model.

[0156] In a possible implementation, interaction simulation is performed based on the initial component model and the threshold interference amount data to determine the stress distribution, including: adding contact properties and interaction parameters to the initial component model to determine the target component model; performing finite element simulation based on the target component model and the threshold interference amount data to determine the stress distribution.

[0157] In practical applications, considering that the friction force has little influence on the model results after assembly and for the convenience of model convergence, a frictionless contact property is adopted. Between the feedback rod and the baffle: the master surface is selected as the mating hole surface of the baffle, the slave surface is selected as the mating shaft surface of the feedback rod, and the interference amount is selected as the maximum interference amount of 0.012 mm.

[0158] Furthermore, between the baffle and the spring tube: the master surface is selected as the mating hole surface of the spring tube, the slave surface is selected as the mating shaft surface of the baffle, and the interference amount is selected as the maximum interference amount of 0.012 mm.

[0159] Furthermore, between the armature and the baffle: the master surface is selected as the mating shaft surface of the baffle, the slave surface is selected as the mating hole surface of the armature, and the interference amount is selected as the maximum interference amount of 0.02 mm. The interaction settings are applied to all analysis steps.

[0160] After the above parameter settings, finite element simulation can be carried out to obtain the finite element simulation results. See Figure 8 , which is the stress nephogram of the feedback rod simulation. See Figure 9 , which is the stress nephogram of the baffle. See Figure 10 , which is the stress nephogram of the spring tube. See Figure 11 , which is the stress nephogram of the armature.

[0161] Step 103: Determine the initial stress data based on the stress distribution and the storage conditions.

[0162] Among them, the storage conditions can be time conditions. For example, store for 10 years. The initial stress data can be the initial stress value, that is, the minimum stress value that meets the storage conditions.

[0163] In a possible implementation, determining the initial stress data based on the stress distribution and the storage conditions includes: extracting the target stress based on the stress distribution; determining the initial stress data based on the target stress and the storage conditions.

[0164] Among them, the target stress can be the maximum stress in the simulation results.

[0165] In practical applications, the maximum stress is extracted from the simulation results, that is, the stress value of the part after stress relaxation, which is used for subsequent calculation of the initial stress value. The interference amount of the parts in the component after a long time of stress relaxation should meet the requirement of not less than the minimum interference amount, and the stress corresponding to this interference amount is the result after the part has experienced stress relaxation. Therefore, it is necessary to inversely calculate the initial minimum stress corresponding to this stress through an accelerated creep model. For details, see the following steps.

[0166] In a possible implementation, the initial stress data is determined based on the target stress and storage conditions, including: performing a creep test based on the target stress and storage conditions to determine the relaxation rate; determining the initial stress data based on the relaxation rate.

[0167] (1) Specifically, measure and record the cross-sectional diameter and gauge length within the gauge of the creep specimen at room temperature;

[0168] (2) Install the creep specimen on the equipment fixture and zero the force sensor;

[0169] (3) Install the extensometer rod at the gauge of the specimen and install the extensometer. Detect and adjust the coaxiality of the extensometer rod by applying a tensile force less than 500 N to ensure that the difference in the readings of the extensometers on both sides is less than 0.002

[0170] mm. After completing the coaxiality detection, return to the unloaded state and zero the extensometer;

[0171] (4) After the installation and debugging are completed, apply a pre-tensile force of 60 N to the creep specimen to eliminate the gap between the specimen and the equipment. Then, use the creep experiment program for loading and recording. The loading rate is 100 N / s. After loading to the target load, keep the load unchanged and continue for the specified experimental time;

[0172] (5) After the experiment is completed, unload, remove the extensometer rod and extensometer in sequence, remove the specimen and save the data to complete the experiment.

[0173] The operation method of the stress relaxation experiment is as follows:

[0174] (1) Measure and record the cross-sectional diameter and gauge length within the gauge of the stress relaxation specimen at room temperature;

[0175] (2) Install the stress relaxation specimen on the equipment fixture and zero the force sensor;

[0176] (3) After the installation and debugging are completed, apply a pre-tensile force of 60 N to the stress relaxation specimen to eliminate the gap between the specimen and the equipment. Then, use the stress relaxation experiment program for loading and recording. The loading rate is 100 N / s. After loading to the target load, keep the displacement unchanged and continue for 100 h;

[0177] (4) After the experiment, unloading is carried out. After removing the specimen and saving the data, the experiment is completed.

[0178] In the armature assembly, through basic tests on various materials, it is found that the beryllium bronze material has the weakest ability to resist stress relaxation under normal working conditions. Therefore, through long-term creep tests of beryllium bronze Qbe1.9 at room temperature and creep tests under different high-temperature conditions, the stress relaxation ratio of this material after being stored at room temperature for 20 years is explored.

[0179] For the accelerated test of metal materials, the commonly used accelerated model is mainly the Arrhenius acceleration model. Based on a large amount of experimental data, Arrhenius proposed the Arrhenius acceleration model in 1880, which can be used to predict the life of materials or products. It is expressed as:

[0180]

[0181] Among them, v s is the material property degradation index, Q is the activation energy related to the material, T is the absolute temperature, k is the Boltzmann constant, and its value is k = 8.617×10 -5 eV / K -1 .

[0182] Taking the logarithm of both sides of it, we can get:

[0183] ln v s = a + b / T (35)

[0184] Among them, a = lnγ, b = -Q / k.

[0185] It can be seen from the above formula that the logarithm of the material property degradation index has a linear relationship with the reciprocal of the absolute temperature. Applying it to the creep test of beryllium bronze at different temperatures, the expression of v s is

[0186]

[0187] The creep tests of beryllium bronze Qbe1.9 specimens are carried out at room temperature and two different high-temperature conditions of 403K and 433K. It can be found that the strain during the creep process has a linear relationship with the logarithm of time. And the higher the temperature, the higher the strain growth rate. The strain growth rate can be expressed as:

[0188] Δε / ε 0 = v s ln t + C (37)

[0189] Among them, Δε is the strain increment, ε 0 is the initial strain value after loading, t is the creep time, v s and C are temperature-related coefficients.

[0190] Therefore, by performing a linear regression fitting on the relationship between the strain growth rate and the logarithm of time at different temperatures according to Equation (36), the equations of the creep curves at different temperatures can be obtained, as shown in Table 1. The fitting effect is as Figure 12 shown, where the scatter points are the test data, the straight line is the fitting curve, the abscissa is the logarithm of time, and the ordinate p / p0 is the stress after storing the corresponding time divided by the initial stress.

[0191] Table 1

[0192]

[0193] For the Arrhenius equation, taking the logarithm of both sides gives the strain growth rate v s , the absolute temperature T, and the thermal activation energy Q required for dislocation movement satisfy the following equation:

[0194]

[0195] It can be seen that there is a linear relationship between the strain growth rate and the reciprocal of temperature during the creep process, and a linear regression fitting is performed on the two.

[0196] The fitting equation is:

[0197]

[0198] If the creep time t = 1 and it is substituted into the equation of the strain growth rate (Equation (36)), it can be seen that the integration constant C in the creep equation can be regarded as the strain growth rate after one hour of creep, that is:

[0199]

[0200] Taking the logarithm of both sides respectively gives:

[0201]

[0202] From Equation (40), it can be seen that there is also a linear relationship between the logarithm of the integration constant C and the reciprocal of temperature. Fitting the integration constant C in the regression equations at different temperatures fitted in Table 1 with the corresponding temperatures, the fitting effect is as Figure 13 shown, where the scatter points are the test data, the straight line is the fitting curve, and the abscissa T_1 is the reciprocal of time.

[0203] The final fitting equation is:

[0204]

[0205] After calculating v s and C at room temperature (T = 293K), substitute each parameter into the creep strain equation (36), that is:

[0206] Δε / ε 0(室温) = 0.004004 ln t + 0.02526(43)

[0207] Since the creep strain of beryllium bronze is small during long-term storage at room temperature, it can be approximately regarded as a stress relaxation process, and the test force is within the elastic region of the material. Therefore, the stress and strain satisfy:

[0208] p = E × ε(44)

[0209] Then the relaxation rate Δp / p of the material 0 satisfies:

[0210] Δp / p 0(室温) = 0.004004 ln t + 0.02526(45)

[0211] After obtaining the relaxation rate, the initial minimum interference amount corresponding to the initial stress value can be calculated using the thick-walled cylinder theory, that is, the initial stress data.

[0212] Step 104: Determine the interference amount based on the initial stress data and the target stress data.

[0213] In a possible implementation manner, determining the interference amount based on the initial stress data and the target stress data includes: determining the storage stress data from the initial stress data and the target stress data; determining the interference amount based on the storage stress data.

[0214] In practical applications, the data between the initial stress data and the target stress data can all meet the requirement that the component still meets the minimum interference amount after reaching the storage time. According to engineering requirements, appropriate storage stress data can be selected from this range to obtain the final required interference amount.

[0215] The embodiments of the present specification provide a method and device for determining the interference amount of a multi-stage assembly component. The method for determining the interference amount of the multi-stage assembly component includes: determining the yield stress of the part material, and determining the target stress data of the component based on the yield stress; wherein, the component includes at least two parts; determining the threshold interference amount data of two interference-fitting parts, and performing simulation based on the threshold interference amount data to determine the stress distribution; determining the initial stress data based on the stress distribution and the storage conditions; determining the interference amount based on the initial stress data and the target stress data. Through the above solutions, it is ensured that even after long-term storage, the interference fit of the component can still be maintained within the designed requirement range, improving the stability and reliability of the equipment.

[0216] Corresponding to the above method embodiments, the present specification also provides embodiments of a device for determining the interference amount of a multi-stage assembly component, Figure 14The figure shows a schematic structural diagram of an interference amount determination device for a multi-stage assembly component provided by an embodiment of this specification. As Figure 14 shown, the device includes:

[0217] A target stress determination module 1501, configured to determine the yield stress of the material of the interference fit parts, and determine the target stress data of the component based on the yield stress; wherein, the component includes at least two interference fit parts;

[0218] A stress distribution determination module 1502, configured to determine the threshold interference amount data of at least two interference fit parts, and perform simulation based on the threshold interference amount data to determine the stress distribution;

[0219] An initial stress determination module 1503, configured to determine the initial stress data based on the stress distribution and the storage conditions;

[0220] An interference amount determination module 1504, configured to determine the interference amount based on the initial stress data and the target stress data.

[0221] In a possible implementation manner, determining the target stress data of the component based on the yield stress includes:

[0222] Determining the relevant interference amount between the parts based on the assembly relationship of at least two interference fit parts;

[0223] Sorting the relevant interference amounts from small to large to determine the sorting result;

[0224] Selecting the first interference amount in the sorting result as the target stress data.

[0225] In a possible implementation manner, performing simulation based on the threshold interference amount data to determine the stress distribution includes:

[0226] Determining the models of at least two interference fit parts and determining the attribute information of the models;

[0227] Performing assembly based on the models and the attribute information to determine the initial component model;

[0228] Performing interaction simulation based on the initial component model and the threshold interference amount data to determine the stress distribution.

[0229] In a possible implementation manner, performing interaction simulation based on the initial component model and the threshold interference amount data to determine the stress distribution includes:

[0230] Adding contact attributes and interaction parameters to the initial component model to determine the target component model;

[0231] Performing finite element simulation based on the target component model and the threshold interference amount data to determine the stress distribution.

[0232] In a possible implementation, initial stress data is determined based on the stress distribution and storage conditions, including:

[0233] Extracting target stress based on the stress distribution;

[0234] Determining initial stress data based on the target stress and storage conditions.

[0235] In a possible implementation, initial stress data is determined based on the target stress and storage conditions, including:

[0236] Conducting a creep test based on the target stress and storage conditions to determine the relaxation rate;

[0237] Determining initial stress data based on the relaxation rate.

[0238] In a possible implementation, the interference amount is determined based on the initial stress data and the target stress data, including:

[0239] Determining storage stress data from the initial stress data and the target stress data;

[0240] Determining the interference amount based on the storage stress data.

[0241] The embodiments of this specification provide a method and device for determining the interference amount of a multi-stage assembly component. The multi-stage assembly component interference amount determination device includes: determining the yield stress of the part material, and determining the target stress data of the component based on the yield stress; wherein, the component includes at least two parts; determining the threshold interference amount data of two interference-fitting parts, and simulating based on the threshold interference amount data to determine the stress distribution; determining the initial stress data based on the stress distribution and storage conditions; determining the interference amount based on the initial stress data and the target stress data. Through the above solutions, it is ensured that even after long-term storage, the interference fit of the component can still be maintained within the range of design requirements, improving the stability and reliability of the equipment.

[0242] The above is a schematic solution of a multi-stage assembly component interference amount determination device of this embodiment. It should be noted that the technical solution of this multi-stage assembly component interference amount determination device and the technical solution of the above multi-stage assembly component interference amount determination method belong to the same concept. For the details not described in the technical solution of the multi-stage assembly component interference amount determination device, reference can be made to the description of the technical solution of the above multi-stage assembly component interference amount determination method.

[0243] Figure 15The structural block diagram of a computing device 1600 provided according to an embodiment of this specification is shown. The components of the computing device 1600 include but are not limited to a memory 1610 and a processor 1620. The processor 1620 is connected to the memory 1610 through a bus 1630, and a database 1650 is used to store data.

[0244] The computing device 1600 further includes an access device 1640, which enables the computing device 1600 to communicate via one or more networks 1660. Examples of these networks include the Public Switched Telephone Network (PSTN), Local Area Network (LAN), Wide Area Network (WAN), Personal Area Network (PAN), or a combination of communication networks such as the Internet. The access device 1640 may include one or more of any type of wired or wireless network interfaces (for example, a network interface card (NIC)), such as an IEEE 802.11 Wireless Local Area Network (WLAN) wireless interface, a Worldwide Interoperability for Microwave Access (Wi-MAX) interface, an Ethernet interface, a Universal Serial Bus (USB) interface, a cellular network interface, a Bluetooth interface, a Near Field Communication (NFC).

[0245] In an embodiment of this specification, the above components of the computing device 1600 and Figure 15 other components not shown may also be connected to each other, for example, through a bus. It should be understood that Figure 15 the shown structural block diagram of the computing device is only for illustrative purposes and not a limitation on the scope of this specification. Those skilled in the art can add or replace other components as needed.

[0246] The computing device 1600 can be any type of stationary or mobile computing device, including mobile computers or mobile computing devices (e.g., tablet computers, personal digital assistants, laptop computers, notebook computers, netbooks, etc.), mobile phones (e.g., smartphones), wearable computing devices (e.g., smartwatches, smart glasses, etc.) or other types of mobile devices, or stationary computing devices such as desktop computers or personal computers (PCs). The computing device 1600 can also be a mobile or stationary server.

[0247] Among them, the processor 1620 is used to execute the following computer-executable instructions, and when the computer-executable instructions are executed by the processor, the steps of the above-mentioned multi-level assembly component interference amount determination method are implemented. The above is a schematic solution of a computing device in this embodiment. It should be noted that the technical solution of this computing device and the technical solution of the above-mentioned multi-level assembly component interference amount determination method belong to the same concept. For the details not described in detail in the technical solution of the computing device, reference can be made to the description of the technical solution of the above-mentioned multi-level assembly component interference amount determination method.

[0248] An embodiment of this specification also provides a computer-readable storage medium, which stores computer-executable instructions, and when the computer-executable instructions are executed by the processor, the steps of the above-mentioned multi-level assembly component interference amount determination method are implemented.

[0249] The above is a schematic solution of a computer-readable storage medium in this embodiment. It should be noted that the technical solution of this storage medium and the technical solution of the above-mentioned multi-level assembly component interference amount determination method belong to the same concept. For the details not described in detail in the technical solution of the storage medium, reference can be made to the description of the technical solution of the above-mentioned multi-level assembly component interference amount determination method.

[0250] An embodiment of this specification also provides a computer program, and when the computer program is executed on a computer, the computer is made to execute the steps of the above-mentioned multi-level assembly component interference amount determination method.

[0251] The above is a schematic solution of a computer program in this embodiment. It should be noted that the technical solution of this computer program and the technical solution of the above-mentioned multi-level assembly component interference amount determination method belong to the same concept. For the details not described in detail in the technical solution of the computer program, reference can be made to the description of the technical solution of the above-mentioned multi-level assembly component interference amount determination method.

[0252] The above description has been made of specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the acts or steps recited in the claims may be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0253] The computer instructions include computer program code, which may be in source code form, object code form, executable file, or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, removable hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0254] It should be noted that for the foregoing method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the embodiments of this specification are not limited by the described order of actions, because according to the embodiments of this specification, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the embodiments of this specification.

[0255] In the above embodiments, the descriptions of the various embodiments have their own focuses. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0256] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The alternative embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of the embodiments of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the embodiments of this specification, so that those skilled in the art can understand and utilize this specification well. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. A method for determining the interference of a multi-level assembly component, characterized in that: include: Determining the yield stress of the materials of at least two interference-fit parts, and determining the target stress data of the component based on the yield stress; wherein the component includes the at least two interference-fit parts; Determine threshold interference data of the at least two interference fit parts, and perform simulation based on the threshold interference data to determine stress distribution; determining initial stress data based on the stress distribution and storage conditions; An interference amount is determined based on the initial stress data and the target stress data.

2. The method according to claim 1, characterized in that The step of determining target stress data of a component based on the yield stress comprises: Determining the relevant interference amounts between the parts based on the assembly relationship of the at least two interference-fit parts; Sorting the related interference amounts from small to large to determine a sorting result; The first interference value of the sorting result is selected as the target stress data.

3. The method according to claim 1, characterized in that The simulating based on the threshold interference data to determine the stress distribution includes: Determining models of the at least two interference fit parts, and determining attribute information of the models; Assemble based on the model and the attribute information to determine an initial component model; An interaction simulation is performed based on the initial component model and the threshold interference data to determine stress distribution.

4. The method according to claim 3, characterized in that The performing interaction simulation based on the initial component model and the threshold interference data to determine the stress distribution includes: Adding contact attributes and interaction parameters to the initial component model to determine a target component model; Finite element simulation is performed based on the target component model and the threshold interference data to determine stress distribution.

5. The method according to claim 1, characterized in that: The determining of initial stress data based on the stress distribution and storage conditions comprises: Extracting target stress based on the stress distribution; Initial stress data is determined based on the target stress and storage conditions.

6. The method according to claim 1, characterized in that The determining of initial stress data based on the target stress and storage conditions comprises: Performing a creep test based on the target stress and storage conditions to determine a relaxation rate; Initial stress data is determined based on the relaxation rate.

7. The method according to claim 1, characterized in that The determining of the interference amount based on the initial stress data and the target stress data comprises: determining stored stress data from the initial stress data and the target stress data; An interference amount is determined based on the stored stress data.

8. A device for determining interference of multi-stage assembly components, characterized in that: include: A target stress determination module is configured to determine the yield stress of the part material, and determine the target stress data of the component based on the yield stress; wherein the component includes at least two interference fit parts; A stress distribution determination module is configured to determine threshold interference data of the at least two interference fit parts, and to perform simulation based on the threshold interference data to determine stress distribution; an initial stress determination module, configured to determine initial stress data based on the stress distribution and storage conditions; The interference determination module is configured to determine the interference based on the initial stress data and the target stress data.

9. A computing device, characterized in that include: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the method for determining the interference amount of a multi-level assembly component as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method for determining interference of multi-level assembly components as claimed in any one of claims 1 to 7.

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