A method for optimizing and improving nominal pitch

Abstract

The present invention provides an optimization and improvement method for the nominal pitch. The present invention first obtains the thread parameters of the bolt and the nut parameters adapted to the bolt, constructs a first strain parameter model through the thread parameters of the bolt, and then simulates the bolt, and sets relevant parameter values, thereby constructing a second strain parameter model of the bolt, wherein the first strain parameter model and the second strain parameter model are both used to obtain the strain parameters of the bolt. Afterwards, the first strain parameter model and the second strain parameter model are combined to construct an initial pitch difference model. On this basis, the initial pitch difference model is further optimized based on the nut parameters, an optimal pitch difference model is established, and the optimal pitch difference model is used to optimize the design of the pitch. Through the optimal pitch difference model, the optimal pitch difference between the pitch of the pre-designed bolt and the pitch of the nut can be obtained, thereby making the bolt more fatigue-resistant.

Description

Technical Field

[0001] The invention relates to the field of bolt design, and in particular to a method for optimizing and improving a nominal thread pitch. Background Art

[0002] At present, in the prior art, bolts usually need to be used in conjunction with nuts, and the pitch of the bolts is usually equal to the pitch of the nuts, and the tightening task is completed by tightening the nuts. However, the existing bolt products do not perform well in terms of fatigue resistance, which is mainly reflected in the stress concentration phenomenon at the first buckle position, which greatly limits their service life and reliability.

[0003] In order to improve this situation, researchers and engineers have been exploring effective methods to improve the fatigue resistance of bolts. One of the proven effective methods is to create a difference between the pitch of the bolt and the pitch of the nut, namely the pitch difference. The pitch difference refers to the distance between the two adjacent teeth of the nut and the bolt after tightening. By properly adjusting this parameter, the stress distribution at the bottom of the thread can be reconstructed, thereby significantly reducing the stress concentration phenomenon of the bolt at the first buckle position.

[0004] In order to obtain this optimal pitch difference, the main method currently used is to perform finite element analysis on the parametric model. Finite element analysis is a powerful computer simulation technology that can simulate in detail the stress and deformation of the bolt under different working conditions. However, finite element analysis usually requires a lot of computing resources and time, which is a challenge for rapid response to market demand and production applications. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0006] To this end, the first aspect of the present invention proposes a method for optimizing and improving the nominal pitch.

[0007] In view of this, a first aspect of the present invention provides a method for optimizing and improving the nominal pitch, comprising: obtaining thread parameters of a bolt and nut parameters matching the bolt; constructing a first strain parameter model of the bolt based on the thread parameters; simulating the bolt to construct a second strain parameter model of the bolt; combining the first strain parameter model with the second strain parameter model to establish an initial pitch difference model; optimizing the initial pitch difference model based on the nut parameters to obtain an optimal pitch difference model, and optimizing the pitch design using the optimal pitch difference model; wherein both the first strain parameter model and the second strain parameter model are used to obtain the strain parameters of the bolt.

[0008] In addition, the optimization and improvement method of the nominal pitch in the above technical solution provided by the present invention may also have the following additional technical features:

[0009] In some technical solutions of the present invention, optionally, based on the thread parameters, a first strain parameter model of the bolt is constructed, including: obtaining the original height parameter and the deformation height parameter of the first circle of thread at the bottom of the bolt; obtaining the height difference parameter based on the original height parameter and the deformation height parameter; and constructing the first strain parameter model based on the height difference parameter and the original height parameter.

[0010] In some technical schemes of the present invention, optionally, the bolt is simulated to construct a second strain parameter model of the bolt, including: using simulation software to simulate the pre-tightening condition of the bolt, obtaining the concentrated position stress parameters of the root of the compression thread of the bolt, the axial average stress parameters of the bolt, and the root axial stress parameters of the thread bottom one layer higher than the compression thread; based on the concentrated position stress parameters and the axial average stress parameters of the bolt, obtaining the first stress concentration coefficient; based on the root axial stress parameters and the axial average stress parameters of the bolt, obtaining the second stress concentration coefficient; based on the first stress concentration coefficient and the second stress concentration coefficient, establishing a second strain parameter model.

[0011] In some technical solutions of the present invention, optionally, the first strain parameter model and the second strain parameter model are combined to establish an initial pitch difference model, including: obtaining an optimal strain parameter based on the second strain parameter model; setting the optimal strain parameter as the output of the first strain parameter model and the output of the second strain parameter model at the same time, and combining the first strain parameter model and the second strain parameter model; integrating and deriving the combined first strain parameter model and the second strain parameter model to establish the initial pitch difference model.

[0012] In some technical solutions of the present invention, optionally, based on the nut parameters, the initial pitch difference model is optimized to obtain the optimal pitch difference model, including: obtaining the height parameter of the nut; based on the height parameter, optimizing the initial pitch difference model to obtain the optimal pitch difference model.

[0013] In some technical schemes of the present invention, optionally, based on the first stress concentration coefficient and the second stress concentration coefficient, a second strain parameter model is established, including: obtaining the number of internal thread layers of the nut connected to the bolt and the number of thread layers of the bolt; based on the number of internal thread layers and the number of thread layers, obtaining stress parameters of the nut at different positions of the bolt, and making the stress parameters of the nut at different positions of the bolt equal; based on the stress parameters of the nut at different positions of the bolt, gradually obtaining the tensile stress parameters of the thread connected to the bottom end of the nut; based on the tensile stress parameters, the first stress concentration coefficient and the second stress concentration coefficient, establishing a second strain parameter model.

[0014] In some technical solutions of the present invention, optionally, a computer-readable storage medium is proposed, on which a program or instruction is stored, and when the program or instruction is executed by a processor, a method for optimizing and improving the nominal pitch as in any of the above technical solutions is implemented.

[0015] By adopting the above technical solution, the optimal pitch difference of threaded fasteners with different materials and different structural parameters under specific working conditions can be quickly calculated, which can not only provide theoretical guidance for the design of the pitch, but also provide an important reference basis for actual production, thereby improving production efficiency and product quality, and ultimately promoting technological progress in the entire industry.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0018] Figure 1 A flowchart of a method for optimizing and improving the nominal pitch according to an embodiment of the present invention;

[0019] Figure 2 A first variation diagram of the axial stress of the bolt thread when the pitch difference changes according to an embodiment of the present invention;

[0020] Figure 3 A second variation diagram of the axial stress of the bolt thread when the pitch difference changes according to an embodiment of the present invention;

[0021] Figure 4 is a diagram showing changes in stress increment when the pitch difference changes according to an embodiment of the present invention;

[0022] Figure 5 A schematic diagram of a bolt and a nut connected according to an embodiment of the present invention;

[0023] Figure 6 A schematic diagram of a stress state of a bolt according to an embodiment of the present invention;

[0024] Figure 7 Schematic diagram of the relationship between the concentrated position stress parameter, the root axial stress parameter and the bolt axial average stress parameter according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0027] Refer to the following Figures 1 to 7 A method for optimizing and improving the nominal pitch according to some embodiments of the present invention is described.

[0028] like Figure 1 As shown, the first aspect of the present invention provides a method for optimizing and improving the nominal pitch, comprising:

[0029] Step 102, obtaining thread parameters of the bolt and parameters of a nut matched with the bolt;

[0030] Step 104, constructing a first strain parameter model of the bolt based on the thread parameters;

[0031] Step 106, simulating the bolt to construct a second strain parameter model of the bolt;

[0032] Step 108, combining the first strain parameter model and the second strain parameter model to establish an initial pitch difference model;

[0033] Step 110, based on the nut parameters, optimizing the initial pitch difference model, obtaining the optimal pitch difference model, and optimizing the pitch design using the optimal pitch difference model;

[0034] Wherein, the first strain parameter model and the second strain parameter model are both used to obtain the strain parameters of the bolt. The present invention proposes an optimization and improvement method for the nominal pitch. Wherein, the calculation methods of the strain parameters of the bolt are divided into two types, one is to obtain according to the thread parameters of the bolt, wherein the thread parameters include but are not limited to the state parameters of the thread under non-stress conditions and the state parameters of the thread under stress conditions, and the other is to obtain according to the stress parameters of the bolt, wherein the stress parameters of the bolt include but are not limited to the stress values ​​of the bolt at different positions when pre-tightened. The present invention first obtains the thread parameters of the bolt and the nut parameters adapted to the bolt, constructs the first strain parameter model through the thread parameters of the bolt, then simulates the bolt, and sets the relevant parameter values, and then constructs the second strain parameter model of the bolt, wherein the first strain parameter model and the second strain parameter model are both used to obtain the strain parameters of the bolt. After that, the first strain parameter model and the second strain parameter model are combined to construct an initial pitch difference model. And on this basis, the initial pitch difference model is further optimized based on the nut parameters, the optimal pitch difference model is established, and the optimal pitch difference model is used to optimize the design of the pitch. Through the optimal pitch difference model, the optimal pitch difference between the pre-designed bolt pitch and the nut pitch can be obtained, thereby making the bolt more fatigue-resistant. The above method can directly obtain the optimal pitch difference based on the corresponding parameters of the bolt and nut, without the need to analyze each case like finite element analysis, reducing the calculation difficulty and running time, optimizing the bolt performance, improving the design efficiency, and enhancing the stability and reliability of the bolt product.

[0035] It should be noted that when the threaded fastener is pre-tightened, the axial stress of the bolt is most concentrated at the root of the thread, so this part is studied in detail. According to the research, if there is no pitch difference between the bolt and the nut, the stress of the thread should be concentrated in one or two turns. As the pitch difference increases, the stress gradually spreads to each turn. When the pitch difference is too large, the stress is concentrated again, concentrated in the top turn. Figure 2 and Figure 3 Shows different pitch differences The stress at the bottom of the thread from -4 to 10 turns on the lower bolt. Outside the clamping area, the stress from -3 to 0 turns of thread is relatively low and uniform, defined as the axial stress at the root of the bolt tooth, expressed as The peak stress from -4 to +7 threads is expressed as The difference between the basic stress and the peak stress is defined as the stress increment, expressed as It is expressed as follows:

[0036] ;

[0037] because represents the stress concentration, so it is necessary to summarize the pitch difference and relationship to analyze and relationship, among which, It is the total fatigue life of the bolt, which is divided into initial fatigue life and residual fatigue life. The calculation formula is: . is the initial fatigue life, is the residual fatigue life. The initial fatigue life is the service life of the bolt before cracks appear, and the residual fatigue life is the fatigue life from the appearance of cracks to complete fracture. Figure 4 Shows and Therefore, the normal distribution equation is used for fitting. The fitting result is represented by the black curve, and its expression is:

[0038] ;

[0039] Therefore, when When I was very young, Appears in the 1st and 2nd thread circle, when When it is very big, Appears on the 5th and 6th threads. Moderate threaded fasteners The weakest. Smaller or larger threaded fasteners have the same Here, the following two issues need to be proven: The fastener has the lowest , whether it has the longest N under dynamic load; and whether it has the same Whether the fasteners have the same N. Therefore, a tensile fatigue test is required to prove them.

[0040] according to , and The relationship between is the stress amplitude, and the specific calculation formula is: ,in is the maximum stress amplitude, is the minimum stress amplitude), we can get the pitch difference The range of threaded fasteners within this range can improve fatigue life more than ordinary fasteners. If we want to use this pitch difference range, we must know the optimal pitch difference In the prior art, the finite element parametric model can only be repeatedly calculated to obtain Therefore, in order to simplify the strain acquisition of the fastener based on the optimal pitch difference methods should establish The mathematical model of .

[0041] Furthermore, in some embodiments of the present invention, a first strain parameter model of the bolt is constructed based on the thread parameters, including: obtaining an original height parameter and a deformation height parameter of the first thread circle at the bottom of the bolt; obtaining a height difference parameter based on the original height parameter and the deformation height parameter; and constructing a first strain parameter model based on the height difference parameter and the original height parameter.

[0042] In this embodiment, the original height of the first thread circle on the bolt when the bolt is not connected to the nut is obtained and the value of the original height is used as the parameter value, that is, the original height parameter. Thereafter, the height of the first thread circle on the bolt after the bolt is tightened by the nut is obtained and the value of the height after the deformation is used as the parameter value, that is, the deformation height parameter. According to the original height parameter and the deformation height parameter, the height difference parameter can be obtained, and according to this height difference parameter and the original height parameter, the first strain parameter model can be established, and the stress parameter of the bolt can be obtained through the first strain parameter model. Through the first strain parameter model, it is possible to provide an important basis for the design of the pitch and subsequent processing, predict the strain of the bolt under different design parameters, thereby optimizing the structure of the bolt, reducing the test time and cost, and improving the accuracy and repeatability of the test.

[0043] Specifically, one of the calculation methods of strain parameters is: .in, is the strain parameter, is the difference between the original height and the height after deformation, is the original height. Then, according to the requirements and the input parameters, the first strain parameter model can be obtained as: .in, is the deformation height parameter, is the original height parameter, is the height difference parameter, The calculation formula is: = .

[0044] It should be understood that when a nut with an optimal pitch difference is tightened onto a bolt, the bolt will deform in the axial direction.

[0045] Furthermore, in some embodiments of the present invention, the bolt is simulated to construct a second strain parameter model of the bolt, including: using simulation software to simulate the pre-tightening condition of the bolt, obtaining the concentrated position stress parameters of the root of the compression thread of the bolt, the bolt axial average stress parameters on the radial section of the compression thread, and the root axial stress parameters of the thread bottom one layer higher than the compression thread; based on the concentrated position stress parameters and the bolt axial average stress parameters, obtaining the first stress concentration coefficient; based on the root axial stress parameters and the bolt axial average stress parameters, obtaining the second stress concentration coefficient; based on the first stress concentration coefficient and the second stress concentration coefficient, establishing a second strain parameter model.

[0046] In this embodiment, when the bolt is tightened by the nut, the thread on the bolt will be subjected to pressure from the nut, and this pressure value is the stress of the thread. First, the bolt is simulated using simulation software to simulate the situation when the bolt is pre-tightened, and then the thread on the bolt will generate corresponding stress. At this time, the axial stress on the root of the compressed thread on the bolt is obtained, that is, the concentrated position stress parameter; at the same time, the axial stress on the thread bottom one layer higher than the above-mentioned compressed thread is obtained, that is, the root axial stress parameter; then, the average axial stress parameter of the bolt is obtained.

[0047] On this basis, according to the different axial stresses, stress concentration parameters are obtained respectively. Among them, based on the stress parameter of the concentrated position and the average axial stress parameter of the bolt, the stress concentration coefficient of the loaded thread root of the bolt is obtained, that is, the first stress concentration coefficient; based on the root axial stress parameter and the average axial stress parameter of the bolt, the stress concentration coefficient of the loaded upper thread root of the bolt is obtained, that is, the second stress concentration coefficient. Then, based on the first stress concentration coefficient and the second stress concentration coefficient, a second strain parameter model is established, and the second strain parameter model is also used to obtain stress parameters. The second strain parameter model can provide an important basis for the design of the pitch and subsequent processing, optimize the bolt design, and enhance the flexibility of the design.

[0048] Specifically, the calculation formula of the first stress concentration factor is: .in, is the first stress concentration factor, is the stress parameter at the concentrated location, is the average axial stress parameter of the bolt. The calculation formula of the second stress concentration factor is: .in, is the second stress concentration factor, is the root axial stress parameter.

[0049] Furthermore, in some embodiments of the present invention, the first strain parameter model and the second strain parameter model are combined to establish an initial pitch difference model, including: obtaining an optimal strain parameter based on the second strain parameter model; setting the optimal strain parameter as the output of the first strain parameter model and the output of the second strain parameter model at the same time, and combining the first strain parameter model and the second strain parameter model; integrating and deriving the combined first strain parameter model and the second strain parameter model to establish the initial pitch difference model.

[0050] In this embodiment, because both the first strain parameter model and the second strain parameter model are used to obtain the strain parameters of the bolt. Then the present application uses the second strain parameter model to calculate and obtain the optimal strain parameter, wherein the optimal strain parameter is the strain value when the bolt and the nut have the optimal pitch difference. To obtain the optimal strain parameter of the bolt, the optimal strain parameter is set as the output of the first strain parameter model and the output of the second strain parameter model at the same time. In this way, the first strain parameter model and the second strain parameter model can be combined, and then the combined first strain parameter model and the second strain parameter model are integrated and derived to establish an initial pitch difference model, improve the scientific nature of the bolt design, optimize the pitch design, and do not need to analyze each case like finite element analysis. You only need to bring in the parameters to obtain the pitch difference, which reduces the difficulty of calculation and running time.

[0051] It should be noted that when the nut parameters and the bolt parameters are standard values, the initial pitch difference model can directly obtain the optimal pitch difference. For example, in the prior art, the nuts are all nuts with five layers of threads and the height of the nuts is 10 mm, so the optimal pitch difference can be directly obtained through the initial pitch difference model.

[0052] Specifically, .in, is the tensile stress parameter of the thread connected to the bottom end of the nut, is Young's modulus, is the optimal strain parameter. Young's modulus is a physical quantity that describes the ability of solid materials to resist deformation. Young's modulus, also known as tensile modulus, is the most common type of elastic modulus or modulus of elasticity. When it is the optimal pitch difference, the initial pitch difference model can be established. The initial pitch difference model is: .in, is the optimal pitch difference, D is the nominal diameter of the bolt, The preload force of the bolt.

[0053] Furthermore, in some embodiments of the present invention, based on the nut parameters, the initial pitch difference model is optimized to obtain the optimal pitch difference model, including: obtaining the height parameter of the nut; based on the height parameter, optimizing the initial pitch difference model to obtain the optimal pitch difference model.

[0054] In this embodiment, the nut can be further improved according to the matching nut parameters of the bolt, thereby obtaining the optimal pitch difference. Among them, the initial pitch difference model is optimized by the height parameter of the nut to obtain the optimal pitch difference model, further optimize the pitch design, extend the service life of the bolt and nut, and improve the accuracy of the optimal pitch difference.

[0055] Specifically, when the height of the nut increases compared to the original height, the calculation formula for the optimal pitch difference is: .in, It is the height parameter of the nut, in millimeters.

[0056] Furthermore, in some embodiments of the present invention, a second strain parameter model is established based on the first stress concentration coefficient and the second stress concentration coefficient, including: obtaining the number of internal thread layers of the nut connected to the bolt and the number of thread layers of the bolt; based on the number of internal thread layers and the number of thread layers, obtaining stress parameters of the nut at different positions of the bolt, and making the stress parameters of the nut at different positions of the bolt equal; based on the stress parameters of the nut at different positions of the bolt, gradually obtaining the tensile stress parameters of the thread connected to the bottom end of the nut; based on the tensile stress parameters, the first stress concentration coefficient and the second stress concentration coefficient, establishing a second strain parameter model.

[0057] In this embodiment, it should be noted that when the nut and the bolt are connected, they are gradually connected as the threads are tightened layer by layer, and the specific tightening situation will be specifically analyzed according to the number of thread layers of the bolt and the number of thread layers of the nut. Then, firstly, the number of internal thread layers of the nut connected with the bolt and the number of thread layers of the bolt are obtained.

[0058] Then, according to the number of internal thread layers and the number of thread layers, the stress parameters of the nut and bolt when tightened at different layers can be calculated layer by layer and the stress parameters of these different layers can be made equal. Based on these stress parameters, the tensile stress parameters of the thread connected to the bottom end of the nut can be gradually obtained.

[0059] Finally, a second strain parameter model is established based on the tensile stress parameter, the first stress concentration factor and the second stress concentration factor.

[0060] Specifically, in one embodiment, Figure 5As shown in the figure, the nut has 5 layers of threads. When pre-tightening ordinary threaded fasteners, AE always keeps in contact. However, the pitch difference fasteners are different. At the beginning of pre-tightening, only E is in contact. As the pre-tightening force F increases, D→C→B→A gradually contact.

[0061] In order to ensure that the stress at the bottom of each bolt tooth is consistent from -3 to 4, we have:

[0062] = = = = = = ;in, , , , , Represent the upper thread root stress of the bolt at the loaded position E, D, C, B, and A respectively; , , , , They represent the stress at the stress concentration position of the bolt thread root at positions E, D, C, B, and A respectively. It represents the stress at the bottom of bolt teeth from -1 to -3 and below. According to the above equation, we know: = , = , = , = , = ;but, Always greater than , so we can only near If you know and The relationship between can be used to solve the above equation.

[0063] Table 1

[0064]

[0065] like Figure 5 As shown in Table 1, at the beginning of tightening, only E is in contact, and the stress at the bottom of the bolt at position 4 is , the stress at position 3 to -3 is Since the distance between the bolt tooth bottom and the contact area at position 4 is relatively close, Greater than During the process of increasing the preload, positions E and D come into contact and generate contact force, while position 4 remains The stress generated by the contact between D and E accumulates at the bolt root at position 3, so the stress here is , and the next thread root also accumulates the stress generated by the contact between D and E ,in Greater than Similarly, when A to E are all in contact, the stress at the bottom of each bolt tooth is shown in the rightmost column of Table 1.

[0066] On this basis, the stress parameter set of nuts and bolts when tightened at different layers is calculated layer by layer. The calculation method is as follows.

[0067] ;

[0068] It follows that:

[0069] ;

[0070] It follows that:

[0071] ; and then we can conclude:

[0072] ;

[0073] It follows that:

[0074] ;

[0075] It follows that:

[0076] .

[0077] like Figure 6 As shown, it schematically shows the specific location of each stress when the nut has only one circle of thread.

[0078] like Figure 7 As shown, Figure 7 The starting position of the arrow in , , , , Represent the average axial stress of the bolt at positions E, D, C, and B respectively; , , , , They represent the upper thread root stress at the loaded positions of the bolts at E, D, C, B, and A respectively; , , , , They represent the stress concentration positions of the bolt thread root at positions E, D, C, B, and A, respectively. , and The ratios are 9.6:4.3:1. , and When, according to Figure 7 You can get , , and .

[0079] Finally, the tensile stress parameters of the nut at position A (i.e. the thread connected to the bottom end of the nut) are obtained. , whose magnitude is also equal to the radial cross-sectional stress at position A, that is, the average axial stress of the bolt, which causes the bolt to move axially, which is approximately equal to the pitch difference.

[0080] In some embodiments, optionally, a computer-readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the method for optimizing and improving the nominal pitch in any of the above embodiments is implemented, thereby having all the beneficial technical effects of the method for optimizing and improving the nominal pitch in any of the above embodiments.

[0081] The computer readable storage medium includes a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0082] A computer-readable storage medium may be a tangible device that can retain and store instructions for use by an instruction execution device, and may be an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above devices, but is not limited thereto. A non-exhaustive list of more specific examples of computer-readable storage media includes: portable computer floppy disks, hard disks, random access memories, read-only memories, erasable programmable read-only memories, static random access memories, portable compact disk read-only memories, digital versatile disks, memory cards, floppy disks, encoding mechanical devices (such as punched cards or grooves with raised structures having instructions recorded therein), and any suitable combination of the above devices. The computer-readable storage medium used herein should not be understood as a transmission signal itself, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media, or electrical signals transmitted through wires, etc.

[0083] In one specific embodiment, the workflow of the present invention is as follows:

[0084] First, obtain the original height of the first thread on the bolt when it is not connected to the nut, that is, the original height parameter ; After that, the height of the first thread on the bolt (i.e., the thread on the bolt used to obtain the original height) after the bolt is tightened by the nut is obtained after the deformation, i.e., the deformation height parameter . According to the original height parameter and deformation height parameters , can obtain the height difference parameter , according to the height difference parameter With the original height parameter , establish the first strain parameter model.

[0085] Secondly, simulation software is used to simulate the situation when the bolt is tightened by the nut, and the axial stress on the root of the compressed thread on the bolt is obtained, that is, the concentrated position stress parameter At the same time, the axial stress of the thread root one layer higher than the above-mentioned compressed thread is obtained, that is, the root axial stress parameter ; Then, obtain the average axial stress parameter of the bolt Based on the stress parameters at the concentrated location The average axial stress parameter of the bolt , get the first stress concentration factor ; Based on the root axial stress parameters The average axial stress parameter of the bolt , obtain the second stress concentration factor .

[0086] On this basis, because the nut and bolt are connected gradually as the threads are tightened layer by layer, and the specific tightening situation will be analyzed specifically according to the number of thread layers of the bolt and the number of thread layers of the nut. Therefore, first obtain the number of internal thread layers of the nut connected to the bolt and the number of thread layers of the bolt.

[0087] Then, according to the number of internal thread layers and thread layers, the stress parameters of the nut and bolt when tightened at different layers can be calculated layer by layer, and the stress parameters of the nut at different positions on the bolt can be made equal. Then, the tensile stress parameters of the thread connected to the bottom end of the nut can be obtained through the stress parameters of the nut at different positions on the bolt. , and according to the tensile stress parameter , the first stress concentration factor and the second stress concentration factor , establish the second strain parameter model , the second strain parameter model is also used to obtain the strain parameters It should be noted that, in the case of the optimal pitch difference, the stress parameters of each thread should be the same. In this case, by setting the stress parameters of the nut at different positions of the bolt to be equal, the strain parameters of the bolt under the optimal pitch difference can also be obtained.

[0088] At this time, because the second strain parameter model is established through simulation, the second strain parameter model can obtain the strain parameters under the optimal pitch difference, that is, the optimal strain parameters, by setting the stress parameters at different bolt positions to be equal before simulation and then simulating the bolts and nuts. , the optimal strain parameter At the same time, the output of the first strain parameter model and the output of the second strain parameter model are set, so that the first strain parameter model and the second strain parameter model can be combined, and then the combined first strain parameter model and the second strain parameter model are combined. Perform integrated derivation to establish the initial pitch difference model .

[0089] Finally, through the height parameter of the nut , optimize the initial pitch difference model, adjust the pitch difference accordingly, and obtain the optimal pitch difference model . Set the height parameter , original height parameters and tensile stress parameters Substitute it into the optimal pitch difference model to obtain the optimal pitch difference of the pre-designed bolt , and according to the optimal pitch difference Optimize the pitch, where the pitch can be the pitch of the bolt or the pitch of the nut. The difference between the pitch of the bolt and the pitch of the nut is the optimal pitch difference. That's it.

[0090] In the claims, specification and drawings of the present invention, the term "multiple" refers to two or more than two. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, which is only for the purpose of more conveniently describing the present invention and making the description process simpler, rather than indicating or implying that the device or element referred to must have the specific orientation described, be constructed and operated in a specific orientation, so these descriptions cannot be understood as limiting the present invention; the terms "connect", "install", "fix" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection between multiple objects, or a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects, or an indirect connection between multiple objects through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood based on the specific circumstances of the above data.

[0091] In the claims, specification and drawings of the present invention, the description of the terms "one embodiment", "some embodiments", "specific embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In the claims, specification and drawings of the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for optimizing and improving the nominal pitch, characterized in that: include: Obtaining thread parameters of the bolt and parameters of the nut matching the bolt; Based on the thread parameters, constructing a first strain parameter model of the bolt; Construct the first strain parameter model of the bolt, including: Obtaining a height difference parameter based on the original height parameter and the deformed height parameter; Constructing a first strain parameter model based on the height difference parameter and the original height parameter; Simulating the bolt to construct a second strain parameter model of the bolt; Construct the second strain parameter model of the bolt, including: The first stress concentration factor and the second stress concentration factor are obtained respectively; and a second strain parameter model is established based on the first and second stress concentration factors. The establishment of the second strain parameter model specifically includes: Get the number of internal thread layers of the nut and the number of thread layers of the bolt; Obtain stress parameters; Obtaining tensile stress parameters; Establishing a second strain parameter model; Combining the first strain parameter model and the second strain parameter model to establish an initial pitch difference model; When the first strain parameter model and the second strain parameter model are combined to establish the initial pitch difference model: Based on the second strain parameter model, obtaining an optimal strain parameter; The optimal strain parameter is set as the output of the first strain parameter model and the output of the second strain parameter model at the same time, and the first strain parameter model and the second strain parameter model are jointly established; Integrate and derive the first strain parameter model and the second strain parameter model after the combination to establish the initial pitch difference model; Based on the nut parameters, the initial pitch difference model is optimized to obtain an optimal pitch difference model, and the pitch design is optimized using the optimal pitch difference model; When optimizing the initial pitch difference model based on the nut parameters to obtain the optimal pitch difference model: Get the height parameter of the nut; Based on the height parameter, the initial pitch difference model is optimized to obtain an optimal pitch difference model; Wherein, the first strain parameter model and the second strain parameter model are both used to obtain the strain parameters of the bolt; Among them, the first strain parameter model is: ;in, is the strain parameter, is a deformation height parameter, which is the height of the first thread on the bolt after the bolt is tightened by the nut. is the original height parameter, which is the original height of the first thread on the bolt when the bolt is not connected with the nut. is the height difference parameter, The calculation formula is: = ; Second strain parameter model , is the tensile stress parameter of the thread connected to the bottom end of the nut, is Young's modulus; Among them, the calculation formula of the first stress concentration factor is: ;in, is the first stress concentration factor, is the stress parameter at the concentrated location, is the average axial stress parameter of the bolt; the calculation formula of the second stress concentration factor is: ;in, is the second stress concentration factor, is the root axial stress parameter; Among them, the initial pitch difference model is: ;in, is the optimal pitch difference, D is the nominal diameter of the bolt, is the bolt preload; The calculation formula for the optimal pitch difference is: ;in, It is the height parameter of the nut, in millimeters.

2. A computer-readable storage medium storing a program or instruction, characterized in that: When the program or the instruction is executed by the processor, the method for optimizing and improving the nominal pitch described in claim 1 is implemented.

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