Steering Column Tube Adjustment Friction Resistance Analysis Method, Device, Equipment and Storage Medium

Abstract

The present invention belongs to the technical field of simulation analysis, and specifically relates to a method, device, equipment and storage medium for analyzing the adjustment friction resistance of a steering column tube. It includes: First, establish a finite element model of the steering column tube and the bracket; Second, define the contact and boundary conditions and define the material properties of the finite element model; Third, calculate the change value of the friction resistance; Fourth, adjust the unevenness of the bracket at the position of the third bolt; Fifth, calculate the change value of the friction resistance; Sixth, adjust the unevenness of the bracket at the position of the fourth bolt; Seventh, calculate the change value of the friction resistance; Eighth, judge the influence on the adjustment friction resistance of the steering column tube according to the change of the contact surface friction resistance. The present invention can directly judge the magnitude of the steering adjustment resistance during the design stage, timely change the design scheme, shorten the R & D cycle and save the R & D cost; in addition, the present invention can effectively simulate the influence of the force deformation of the steering column tube bracket during the assembly process on the adjustment friction resistance of the steering column tube, and guide the design of the steering column tube bracket.

Description

Technical Field

[0001] The present invention belongs to the technical field of simulation analysis, and specifically relates to a method, device, equipment and storage medium for analyzing the adjustment friction resistance of a steering column tube. Background Art

[0002] With the continuous development of China's automobile industry, the quality of automobiles has been continuously improved, and the safety of automobiles has received increasing attention. People have higher and higher requirements for the performance of automobile parts. The function of the steering control mechanism is to transmit the force exerted by the driver on the steering wheel to the steering gear. At present, in order to ensure the safety of the driver and also to more comfortably and reliably operate the steering system, it is usually required that the steering control mechanism has good maneuverability during operation, which requires that the resistance during adjustment should not be too large.

[0003] CAE simulation analysis, as a key technology for predicting the stress distribution, static strength and other performances of automobile parts, has been widely used in product development. The steering control mechanism, as a key part during the steering process of an automobile, its motion state is directly related to the driving safety of the automobile. The steering control mechanism generally includes a steering wheel, a steering shaft, a steering column tube, a steering main pipe bracket, a universal joint, etc.

[0004] As a part of the steering control mechanism, the angle of the steering column tube can be adjusted according to the usage requirements of different drivers. However, in the actual operation process, the adjustment friction resistance may be too large, which brings a lot of inconvenience to the driver. At present, for the problem of too large adjustment friction resistance of the steering column tube, it usually appears during the test process. Once a problem occurs, relevant parts need to be modified again, which increases the product development cost and is not conducive to the control of the product development cycle.

[0005] The steering column tube is usually fixed on the cross beam through a bracket. For the analysis of the steering column tube bracket, the bracket and the cross beam are usually connected with a rigid unit, and a unit load is applied at the other end of the bracket to calculate the stiffness of the bracket. This method can only provide the stiffness of one bracket as a reference and does not consider the influence of the bolt tightening sequence and tightening force on the deformation of the bracket during the actual assembly process.

[0006] In summary, there are few CAE analysis methods for predicting the adjustment friction resistance of the steering column tube at present, and the CAE analysis of the steering column tube bracket does not consider the influence of the bolt tightening sequence and tightening force during the assembly process. Summary of the Invention

[0007] The present invention provides a method, device, equipment and storage medium for analyzing the frictional resistance of a steering column tube adjustment, which can directly judge the magnitude of the steering adjustment resistance during the design stage, timely change the design scheme, shorten the R & D cycle, and save the R & D cost; in addition, the present invention can effectively simulate the influence of the force deformation of the steering column tube bracket during the assembly process on the frictional resistance of the steering column tube adjustment, guide the design of the steering column tube bracket, and solve the problem that the existing prediction of the magnitude of the adjustment frictional resistance of the steering column tube does not consider the influence of the bolt tightening sequence and tightening force during the assembly process in the CAE analysis of the steering column tube bracket.

[0008] The technical solution of the present invention is described in conjunction with the accompanying drawings as follows:

[0009] In a first aspect, an embodiment of the present invention provides a method for analyzing the frictional resistance of a steering column tube adjustment, including the following steps:

[0010] Step 1: Establish a finite element model of the steering column tube and the bracket using solid network elements;

[0011] Step 2: Define the contact and boundary conditions, and define the material properties of the finite element model, including defining the material elastic modulus and Poisson's ratio, and using linear elastic material properties in the analysis;

[0012] Step 3: Apply the bolt pre-tightening force, record the pressure on the contact surface, and obtain the frictional resistance of the contact surface; apply the steering column adjustment load, record the pressure on the contact surface, and calculate the change value of the frictional resistance; apply the bolt pre-tightening force in sequence and calculate the change value of the frictional resistance;

[0013] Step 4: Adjust the unevenness of the bracket at the position of the third tightened bolt, and adjust the unevenness of the model by 0.6 mm in the opposite direction of the deformation of the bracket after the bolt is tightened, and keep the other positions of the model unchanged.

[0014] Step 5: Apply the bolt pre-tightening force in sequence and calculate the change value of the frictional resistance;

[0015] Step 6: Adjust the unevenness of the bracket at the position of the fourth tightened bolt by 0.9 mm, and keep the other positions of the model unchanged;

[0016] Step 7: Apply the bolt pre-tightening force in sequence and calculate the change value of the frictional resistance;

[0017] Step 8: Compare the change in the frictional resistance of the contact surface, and judge the influence on the frictional resistance of the steering column tube adjustment according to the change in the frictional resistance of the contact surface.

[0018] Furthermore, in the first step, the bracket includes a fixed bracket, a mounting bracket, and a welding bracket; the fixed bracket, the mounting bracket, the welding bracket, the steering column tube, and the bolts are modeled using first-order hexahedrons, and the other components are modeled using tetrahedrons; the position of the shell of the steering column tube and the rotating shaft at the lower end of the welding bracket is defined and linked with the keyword *Hinge to enable the steering column tube to rotate around the rotating shaft.

[0019] Furthermore, the specific method of the second step is as follows:

[0020] Assemble the model according to the actual installation positions of the components in the steering column tube assembly. Among them, a binding constraint relationship is established between the tube beam and the fixed bracket; contact relationships are established between the fixed bracket and the mounting bracket, between the column tube shell and the steering column tube, and between the welding bracket and the column tube shell; and the degrees of freedom in the 1-6 directions of the two end faces of the tube beam are constrained.

[0021] Furthermore, the specific method of the third step is as follows:

[0022] 31) Without considering the assembly sequence of the bolts, apply a pre-tightening force to the adjusting bolts and the fixing bolts; among them, the bolt pre-tightening force is obtained from the relationship between the bolt pre-tightening force and the bolt tightening torque and applied to each bolt; calculate the bolt pre-tightening force according to formula (1), where the acting direction of the bolt pre-tightening force is along the axial direction of the bolt, and formula (1) is as follows:

[0023]

[0024] In the formula, F is the bolt pre-tightening force; T is the bolt tightening torque; k is the bolt tightening torque coefficient, taking 0.2; D is the bolt diameter;

[0025] 32) Record the pressure F on the contact surface 13 at the last load step N1 , define the output of the contact surface pressure, and the definition method is:

[0026] *CONTACT PRINT, FREQUENCY = 1, MASTER = contact-m, SLAVE = contact-sCFN;

[0027] 33) Calculate the frictional resistance F according to the pressure on the contact surface using formula (2) f1 , and formula (2) is as follows:

[0028] F fn = f * F Nn (2)

[0029] In the formula, n = 1, 2, 3...; F fn is the frictional resistance of the contact surface; F Nn is the contact surface pressure; f is the friction coefficient;

[0030] 34) Connect each node on the end face of the steering column tube to the midpoint of the end face with rigid elements, and apply a steering column adjustment displacement load at the midpoint of the end face, with the direction according to the movement direction of the steering column tube during the actual working process; record the pressure F on the contact surface after analysis. N2 ; Calculate the frictional resistance F according to formula (2). f2 Then, calculate the change ΔF of the frictional resistance according to formula (3). f1 ;

[0031] ΔF fn = F f2n - F f(2n-1) (3)

[0032] In the formula, n = 1, 2, 3,...; ΔF fn is the change value of the frictional resistance on the contact surface; F f2n and F f(2n-1) are both the frictional resistances on the contact surface;

[0033] 35) If ΔF f1 is greater than the evaluation target value, it indicates that the adjustment frictional resistance is too large and structural adjustment is required;

[0034] 36) Apply the pre-tightening force of the adjustment bolt.

[0035] 37) According to the tightening sequence of the bolts during the actual assembly process, apply the pre-tightening force to the four bolts in four load steps in sequence.

[0036] 38) After calculation and analysis, record the pressure F on the contact surface after applying the pre-tightening force of the adjustment bolt. N3 Record the pressure F on the contact surface after applying the pre-tightening force of the four fixing bolts. N4 . Calculate the corresponding frictional resistances F f3 and F f4 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3). f2 .

[0037] Further, the specific method of step five is as follows:

[0038] 51) Apply the bolt pre-tightening force according to the tightening sequence of the bolts in step three.

[0039] 52) After calculation and analysis, respectively record the pressure F on the contact surface after applying the pre-tightening force of the adjustment bolt 6. N5 and the pressure F on the contact surface after applying the pre-tightening force of the four fixing bolts. N6 ; Calculate the corresponding frictional resistances F f5 and F f6 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3). f3 .

[0040] Further, the specific method of step seven is as follows:

[0041] 71) Apply bolt pre-tightening force according to the tightening sequence of bolts in step six;

[0042] 72) After calculation and analysis, record the pressure F on the contact surface after applying the pre-tightening force of the adjusting bolt 6 N7 and the pressure F on the contact surface after applying the pre-tightening force of the four fixing bolts; calculate the corresponding frictional resistance F N8 according to formula (2); and then calculate the change ΔF of the frictional resistance by using formula (3). f7 and F f8 f4 .

[0043] Further, the specific method of step eight is as follows:

[0044] 81) Calculate the change percentages δ1 and δ2 of the change in the frictional resistance change amount ΔF f3 , ΔF f4 relative to ΔF f2 by using formula (4);

[0045]

[0046] wherein, n = 1, 2, 3,...,, δ n is the change percentage of the change in the frictional resistance change amount;

[0047] 82) If δ1 ≤ 5% and δ2 ≤ 5%, it is considered that the deformation of the bracket caused during the pre-tightening process has no influence on the adjustment frictional resistance of the steering column tube; otherwise, it is considered that the deformation of the bracket caused during the pre-tightening process affects the smoothness of the steering column tube adjustment, and the bracket structure needs to be adjusted.

[0048] Second, the embodiment of the present invention also provides an analysis device for the adjustment frictional resistance of a steering column tube, including:

[0049] A modeling module for establishing a finite element model of the steering column tube and the bracket;

[0050] A definition module for defining contact and boundary conditions, defining the material properties of the finite element model, including defining the material elastic modulus and Poisson's ratio, and adopting linear elastic material properties in the analysis;

[0051] A first calculation module for applying bolt pre-tightening force, recording the pressure on the contact surface, and obtaining the frictional resistance on the contact surface; applying a steering column adjustment load, recording the pressure on the contact surface, and calculating the change value of the frictional resistance; and applying bolt pre-tightening force in sequence and calculating the change value of the frictional resistance;

[0052] ​The first adjustment module is used to adjust the unevenness of the bracket at the third bolt;

[0053] The second calculation module is used to apply bolt pre-tightening forces in sequence and calculate the change value of the friction resistance;

[0054] The second adjustment module is used to adjust the unevenness of the bracket at the fourth bolt;

[0055] The third calculation module is used to apply bolt pre-tightening forces in sequence and calculate the change value of the friction resistance;

[0056] The judgment module is used to compare the change in the contact surface friction resistance and judge the influence on the steering column tube adjustment friction resistance according to the change in the contact surface friction resistance.

[0057] In a third aspect, an embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements a method for analyzing the adjustment friction resistance of a steering column tube as described in any one of the embodiments of the present invention.

[0058] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements a method for analyzing the adjustment friction resistance of a steering column tube as described in any one of the embodiments of the present invention.

[0059] The beneficial effects of the present invention are as follows:

[0060] The present invention can directly judge the magnitude of the steering adjustment resistance during the design stage, can timely change the design scheme, shorten the R & D cycle, and save R & D costs; in addition, it can effectively simulate the influence of the force deformation of the steering column tube bracket during the assembly process on the steering column tube adjustment friction resistance of the present invention, and can guide the design of the steering column tube bracket. [[ID=2,6]]Description of the Drawings

[0061] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0062] Figure 1 It is a schematic diagram of the steering column tube assembly model;

[0063] Figure 2 It is a schematic diagram of the bolt tightening sequence and the contact surface position;

[0064] Figure 3 It is a schematic diagram of the steering column tube loading direction;

[0065] Figure 4 It is a schematic diagram for adjusting the unevenness of the model;

[0066] Figure 5 It is a schematic flow chart of a method for analyzing the adjusting friction resistance of a steering column tube in the first embodiment of the present invention;

[0067] Figure 6 It is a schematic structural diagram of a device for analyzing the adjusting friction resistance of a steering column tube in the second embodiment of the present invention;

[0068] Figure 7 It is a schematic structural diagram of an electronic device in the third embodiment of the present invention. Specific embodiments

[0069] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0070] Embodiment 1

[0071] Figure 5 It is a flow chart of a method for analyzing the adjusting friction resistance of a steering column tube provided in the first embodiment of the present invention. This method can be executed by a device for analyzing the adjusting friction resistance of a steering column tube in the second embodiment of the present invention. The device can be implemented in a software and / or hardware manner, such as Figure 6 As shown, the method specifically includes the following steps:

[0072] A method for analyzing the adjusting friction resistance of a steering column tube includes the following steps:

[0073] Step 1: Use finite element modeling software to perform mesh division on each component in the steering column tube assembly to establish a finite element model of the steering column tube and the bracket;

[0074] Refer to Figure 1 , the bracket includes a fixed bracket 2, a mounting bracket 4, and a welding bracket 5; the fixed bracket 2, the mounting bracket 4, the welding bracket 5, the steering column tube, and the bolt are modeled using first-order hexahedrons. The requirement for the hexahedron element mesh type is C3D8I; other components are modeled using tetrahedrons. The requirement for the first-order tetrahedron element mesh type is C3D4; adjust the meshes at the contact positions between the welding bracket 5 and the housing 7 of the steering column tube, and between the fixed bracket 2 and the mounting bracket 4, so that the nodes at the contact positions are in one-to-one correspondence. The mounting bracket 4 and the welding bracket 5 are connected by welding. It is required to model the weld structure according to the weld model and connect them by the co-node method.

[0075] The housing 7 of the steering column tube is linked to the position of the rotating shaft at the lower end of the welding bracket 5 by defining a connection with the keyword *Hinge, enabling the steering column tube to rotate around the rotating shaft.

[0076] The Hinge definition method is as follows:

[0077] *CONNECTOR SECTION, ELSET= Unit set name

[0078] HINGE,

[0079] Local coordinate system name said.

[0080] Step 2: Define the contact and boundary conditions, and define the material properties of the finite element model, including defining the elastic modulus and Poisson's ratio of the material. Linear elastic material properties are adopted in the analysis;

[0081] Assemble the model according to the actual installation positions of the various components in the steering column tube assembly. Among them, a bonded constraint relationship is established between the tube beam 1 and the fixed bracket 2; contact relationships are established between the fixed bracket 2 and the mounting bracket 4, between the housing 7 of the steering column tube and the steering column tube 8, and between the welding bracket 5 and the housing 7 of the steering column tube; and the degrees of freedom in the 1-6 directions of the two end faces of the tube beam are constrained. The first contact surface 13 between the welding bracket 5 and the housing 7 of the steering column tube (due to structural symmetry, only one of the first contact surface 13 or the second contact surface 14 needs to be concerned) is the main contact surface of this method. The housing 7 side of the steering column tube is defined as the master surface, named contact-m, and the welding bracket 5 side is defined as the slave surface, named contact-s. The friction coefficient f = 0.15 is set in the contact relationship.

[0082] Generally, the steering column tube 8 and the brackets are made of steel material, with an elastic modulus E = 210000 MPa and a Poisson's ratio μ = 0.3.

[0083] Refer to Figure 2 and Figure 3 , Step 3: Apply the bolt pre-tightening force, record the pressure on the contact surface, and obtain the frictional resistance of the contact surface; apply the steering column adjustment load, record the pressure on the contact surface, and calculate the change value of the frictional resistance; apply the bolt pre-tightening force in sequence and calculate the change value of the frictional resistance;

[0084] 31) Without considering the assembly sequence of the bolts, apply pre-tightening forces to the adjusting bolt 6 and the first, second, third, and fourth fixing bolts 9, 10, 11, 12; among them, the bolt pre-tightening force is obtained from the relationship between the bolt pre-tightening force and the bolt tightening torque and applied to each bolt; the bolt pre-tightening force is calculated according to formula (1), where the acting direction of the bolt pre-tightening force is along the axial direction of the bolt, and formula (1) is as follows:

[0085]

[0086] In the formula, F is the bolt pre-tightening force; T is the bolt tightening torque; k is the bolt tightening torque coefficient, taking 0.2; D is the bolt diameter;

[0087] It is necessary to record the pressure F on the contact surface 13 at the last load step N1 , define the output of the contact surface pressure, and the definition method is as follows:

[0088] *CONTACT PRINT,FREQUENCY=1,MASTER=contact-m,SLAVE=contact-sCFN,

[0089] Solve through ABAQUS / standard, and the contact surface pressure result is output in the DAT file. The output file is as follows:

[0090] CONTACT OUTPUT FOR SLAVE SURFACE contact-s AND MASTER SURFACEcontact-m

[0091]

[0092] Among them, CFNM is the resultant force of the contact pressure, and CFN1, CFN2, and CFN3 respectively represent the component forces in three directions. CFNM is obtained by the following formula:

[0093]

[0094] Among them, cpress is the contact pressure of each node on the slave surface, S is the area of the slave surface, and n is the number of nodes on the slave surface.

[0095] The contact surface pressure F N1 is the corresponding result of CFNM. After that, according to the pressure F on the contact surface N1 , use formula (2) to calculate the frictional resistance F f1 , and formula (2) is as follows:

[0096] F fn = f * F Nn (2)

[0097] In the formula, n = 1, 2, 3...; F fn is the frictional resistance of the contact surface; F Nn is the contact surface pressure; f is the friction coefficient;

[0098] Connect each node on the end face of the steering column tube to the midpoint of the end face with rigid elements, and apply a steering column adjustment displacement load of 2 mm at this midpoint. The direction is based on the movement direction of the steering column tube during the actual working process, such asFigure 3 ; Record the pressure F on the contact surface after analysis N2 ; Calculate the frictional resistance F according to formula (2) f2 , and then calculate the change ΔF of the frictional resistance according to formula (3) f1 ;

[0099] ΔF fn = F f2n - F f(2n-1) (3)

[0100] In the formula, n = 1, 2, 3,...; ΔF fn is the change value of the frictional resistance on the contact surface; F f2n and F f(2n-1) are both the frictional resistances on the contact surface;

[0101] If ΔF f1 is greater than the evaluation target value, it indicates that the adjusted frictional resistance is too large and structural adjustment is required;

[0102] Apply the pre-tightening force of the adjusting bolt 6; then, according to the tightening sequence of the bolts in the actual assembly process, apply the pre-tightening forces of the first bolt 9, the second bolt 10, the third bolt 11, and the fourth bolt 12 in four load steps in sequence. This step requires that the pre-tightening forces of the five bolts be applied through five load steps, and the corresponding CFNM should be output for each load step. After solving through the ABAQUS / standard solver, record the pressure F on the contact surface after applying the pre-tightening force of the adjusting bolt 6 N3 , record the pressure F on the contact surface after applying the pre-tightening forces of the four fixing bolts N4 . Calculate the corresponding frictional resistances F f3 and F f4 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3) f2

[0103] Step Four. As Figure 4 shown, adjust the unevenness of the mounting bracket 4 at the position of the third bolt 11, and adjust the unevenness of the model by 0.6 mm in the opposite direction of the deformation of the bracket after the bolt is tightened, and keep the models at other positions unchanged.

[0104] During the process of tightening the bolts, each time a bolt is tightened, the bracket will produce corresponding deformation, and the more bolts are tightened, the greater the possible deformation. This step is to simulate the deformation in this process by adjusting the unevenness of the model, and through comparative analysis, it can be intuitively shown whether this deformation has an impact on the change of the frictional resistance at the position of the first contact surface 13.

[0105] Step Five. Apply the bolt pre-tightening forces in sequence and calculate the change value of the frictional resistance;

[0106] 51) Apply the bolt pre-tightening force in accordance with the tightening sequence of the bolts in Step 3;

[0107] 52) After calculation and analysis, record the pressure F on the contact surface after applying the pre-tightening force of the adjusting bolt 6 N5 and the pressure F on the contact surface after applying the pre-tightening force of the four fixing bolts; N6 Calculate the corresponding frictional resistance F f5 and F f6 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3) f3 .

[0108] Step 6: Adjust the unevenness of the bracket at the position of the fourth bolt 12 by 0.9 mm, and keep the model unchanged at other positions;

[0109] Step 7: Apply the bolt pre-tightening force in sequence and calculate the change value of the frictional resistance;

[0110] 71) Apply the bolt pre-tightening force in accordance with the tightening sequence of the bolts in Step 3;

[0111] 72) After calculation and analysis, record the pressure F on the contact surface after applying the pre-tightening force of the adjusting bolt 6 N7 and the pressure F on the contact surface after applying the pre-tightening force of the four fixing bolts; N8 Calculate the corresponding frictional resistance F f7 and F f8 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3) f4 .

[0112] Step 8: Compare the change of the frictional resistance on the contact surface, and judge the influence on the adjustment frictional resistance of the steering column tube according to the change of the frictional resistance on the contact surface.

[0113] Calculate the change percentage δ1, δ2 of the change in the frictional resistance change amount ΔF f3 , ΔF f4 relative to ΔF f2 using formula (4);

[0114]

[0115] In the formula, n = 1, 2, 3,..., δ n is the change percentage of the frictional resistance change amount;

[0116] If δ1 ≤ 5% and δ2 ≤ 5%, it is considered that the deformation of the bracket caused during the pre-tightening process has no influence on the adjustment frictional resistance of the steering column tube; otherwise, it is considered that the deformation of the bracket caused during the pre-tightening process affects the smoothness of the adjustment of the steering column tube, and the bracket structure needs to be adjusted.

[0117] Example 2

[0118] Refer to Figure 6 , a device for analyzing the frictional resistance of a steering column tube adjustment, comprising:

[0119] A modeling module for establishing a finite element model of the steering column tube and the bracket;

[0120] A definition module for defining contact and boundary conditions, and defining the material properties of the finite element model, including defining the material elastic modulus and Poisson's ratio, and using linear elastic material properties in the analysis;

[0121] A first calculation module for applying bolt pre-tightening force, recording the pressure on the contact surface, and obtaining the frictional resistance of the contact surface; applying a steering column adjustment load, recording the pressure on the contact surface, and calculating the change value of the frictional resistance; and applying bolt pre-tightening force in sequence and calculating the change value of the frictional resistance;

[0122] A first adjustment module for adjusting the unevenness of the bracket at the third bolt;

[0123] A second calculation module for applying bolt pre-tightening force in sequence and calculating the change value of the frictional resistance;

[0124] A second adjustment module for adjusting the unevenness of the bracket at the fourth bolt;

[0125] A third calculation module for applying bolt pre-tightening force in sequence and calculating the change value of the frictional resistance;

[0126] A judgment module for comparing the change in the frictional resistance of the contact surface and judging the influence on the frictional resistance of the steering column tube adjustment according to the change in the frictional resistance of the contact surface.

[0127] Embodiment III

[0128] Figure 7 It is a schematic structural diagram of a computer device in Embodiment III of the present invention. Figure 7 It shows a block diagram of an exemplary computer device 102 suitable for implementing the embodiments of the present invention. Figure 7 The shown computer device 102 is only an example and should not bring any limitation to the functions and usage scope of the embodiments of the present invention.

[0129] As Figure 7 shown, the computer device 102 is presented in the form of a general-purpose computing device. The components of the computer device 102 may include but are not limited to: one or more processors or processing units 16, a system memory 28, and a bus 18 connecting different system components (including the system memory 28 and the processing unit 16).

[0130] Bus 18 represents one or more of several types of bus architectures, including a memory bus or memory controller, a peripheral bus, an Accelerated Graphics Port, a processor bus, or a local bus using any of the several bus architectures. By way of example, such architectures include, but are not limited to, Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MAC) bus, Enhanced ISA bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

[0131] Computer device 102 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by computer device 102, including both volatile and nonvolatile media, removable and non-removable media.

[0132] System memory 28 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. Computer device 102 can further include other removable / non-removable, volatile / nonvolatile computer system storage media. By way of example only, storage system 34 can be used for reading and writing non-removable, nonvolatile magnetic media ( Figure 7 not shown and typically called a "hard disk drive"). Although Figure 7 not shown in, a disk drive for reading and writing a removable nonvolatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing a removable nonvolatile optical disk (e.g., CD-ROM, DVD-ROM, or other optical media) can be provided. In these cases, each drive can be connected to bus 18 by one or more data media interfaces. Memory 28 can include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the present invention.

[0133] A program / utility 40 having a set (at least one) of program modules 42 can be stored, for example, in memory 28, and such program modules 42 include - but are not limited to - an operating system, one or more application programs, other program modules, and program data, each of which examples or some combination thereof may include an implementation of a network environment. Program modules 42 typically carry out the functions and / or methods of the embodiments described herein.

[0134] The computer device 102 can also communicate with one or more external devices 14 (such as a keyboard, a pointing device, a display 24, etc.), and can also communicate with one or more devices that enable a user to interact with the computer device 102, and / or communicate with any device that enables the computer device 102 to communicate with one or more other computing devices (such as a network card, a modem, etc.). Such communication can be carried out through the input / output (I / O) interface 22. In addition, in the computer device 102 of this embodiment, the display 24 does not exist as an independent entity, but is embedded in the mirror. When the display surface of the display 24 is not displaying, the display surface of the display 24 and the mirror visually merge into one. Moreover, the computer device 102 can also communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through the network adapter 20. As shown in the figure, the network adapter 20 communicates with other modules of the computer device 102 through the bus 18. It should be understood that although not shown in the figure, other hardware and / or software modules can be used in combination with the computer device 102, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0135] The processing unit 16 executes various functional applications and data processing by running the programs stored in the system memory 28, for example, implementing a method for analyzing the frictional resistance of a steering column tube provided in the embodiments of the present invention.

[0136] Embodiment 4

[0137] Embodiment 4 of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements a method for analyzing the frictional resistance of a steering column tube provided in all the embodiments of the present application.

[0138] Any combination of one or more computer-readable media may be employed. The computer-readable media may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0139] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, in which the computer-readable program code is carried. Such a propagated data signal may take many forms, including—but not limited to—electromagnetic signals, optical signals, or any suitable combination of the foregoing. The computer-readable signal medium may also be any computer-readable medium that is not a computer-readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0140] The program code embodied on the computer-readable medium may be transmitted using any appropriate medium, including—but not limited to—wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0141] The computer program code for carrying out operations of the present invention may be written in one or more programming languages, or combinations thereof, including object-oriented programming languages such as Java, Smalltalk, C++, as well as conventional procedural programming languages such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or it may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0142] Note that the above is only a preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for analyzing the frictional resistance of a steering column tube, characterized in that It includes the following steps: Step 1: Establish a finite element model of the steering column tube and the bracket using entity network units; Step 2: Define the contact and boundary conditions, and define the material properties of the finite element model, including defining the elastic modulus and Poisson's ratio of the material, and using linear elastic material properties in the analysis; Step 3: Apply bolt pre-tightening force, record the pressure on the contact surface, and obtain the frictional resistance of the contact surface; apply the steering column adjustment load, record the pressure on the contact surface, and calculate the change value of the frictional resistance; apply the bolt pre-tightening force in sequence according to the bolt number, and calculate the change value of the frictional resistance; Step 4: Adjust the unevenness of the bracket at the position of the third tightened bolt, and adjust the unevenness of the model by 0.6 mm in the opposite direction of the deformation of the bracket after the bolt is tightened, and the models at other positions remain unchanged; Step 5: Apply the bolt pre-tightening force in sequence according to the bolt number, and calculate the change value of the frictional resistance; Step 6: Adjust the unevenness of the bracket at the position of the fourth tightened bolt by 0.9 mm, and the models at other positions remain unchanged; Step 7: Apply the bolt pre-tightening force in sequence according to the bolt number, and calculate the change value of the frictional resistance; Step 8: Compare the change of the frictional resistance on the contact surface, and judge the influence on the adjustment frictional resistance of the steering column tube according to the change of the frictional resistance on the contact surface.

2. The method for analyzing the steering column tube adjustment frictional resistance according to claim 1, characterized in that In Step 1, the bracket includes a fixed bracket, a mounting bracket and a welding bracket; the fixed bracket, the mounting bracket, the welding bracket, the steering column tube and the bolts are modeled by first-order hexahedrons, and other components are modeled by tetrahedrons; the position of the rotating shaft at the lower end of the shell of the steering column tube and the welding bracket is defined and linked by the keyword *Hinge to realize the rotation of the steering column tube around the rotating shaft.

3. A method for analyzing the adjustment friction resistance of a steering column tube according to claim 1, characterized in that, The specific method of Step 2 is as follows: Assemble the model according to the actual installation positions of the components in the steering column tube assembly. Among them, a binding constraint relationship is established between the pipe beam and the fixed bracket; contact relationships are established between the fixed bracket and the mounting bracket, between the column tube shell and the steering column tube, and between the welding bracket and the column tube shell; and the degrees of freedom in the 1-6 directions of the two end faces of the pipe beam are constrained.

4. The method for analyzing the steering column tube adjustment friction resistance according to claim 1, characterized in that, The specific method of Step 3 is as follows: 31) Without considering the assembly sequence of the bolts, apply pre-tightening force to the adjusting bolts and the fixing bolts; among them, the bolt pre-tightening force is obtained from the relationship between the bolt pre-tightening force and the bolt tightening torque, and is applied to each bolt; the bolt pre-tightening force is calculated according to formula (1), where the acting direction of the bolt pre-tightening force is along the axis of the bolt, and formula (1) is as follows: In the formula, F is the bolt pre-tightening force; T is the bolt tightening torque; k is the bolt tightening torque coefficient, taking 0.2; D is the bolt diameter; 32) Record the pressure F on contact surface 13 at the last load step N1 , define the output of contact surface pressure in the following way: *CONTACT PRINT,FREQUENCY=1,MASTER=contact-m,SLAVE=contact-sCFN; 33) Calculate the frictional resistance F using formula (2) based on the pressure on the contact surface f1 , and formula (2) is as follows: F fn = f * F Nn (2) where n = 1, 2, 3...; F fn is the frictional resistance of the contact surface; F Nn is the contact surface pressure; f is the friction coefficient; 34) Connect each node on the end face of the steering column tube to the midpoint of the end face with rigid elements, and apply a steering column adjustment displacement load at the midpoint of the end face, with the direction according to the movement direction of the steering column tube during the actual working process; record and analyze the pressure F on the contact surface. N2 ; Calculate the frictional resistance F according to formula (2). f2 Then calculate the change ΔF of the frictional resistance according to formula (3). f1 ; ΔF fn = F f2n - F f(2n-1) (3) where n = 1, 2, 3, ……; ΔF fn is the change value of the frictional resistance of the contact surface; F f2n and F f(2n-1) are both the frictional resistances of the contact surface; 35) If ΔF f1 is greater than the evaluation target value, it indicates that the adjusted frictional resistance is too large and structural adjustment is required; 36) Apply the pre-tightening force of the adjusting bolts; 37) According to the tightening sequence of the bolts in the actual assembly process, apply pre-tightening force to the four bolts in four load steps in sequence; 38) After calculation and analysis, record the pressure F on the contact surface after applying the pre-tightening force of the adjusting bolt N3 , and record the pressure F on the contact surface after applying the pre-tightening forces of the four fixing bolts N4 ; Calculate the corresponding frictional resistances F f3 and F f4 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3) f2 .

5. A method for analyzing the adjustment friction resistance of a steering column tube according to claim 4, characterized in that, The specific method of Step 5 is as follows: 51) Apply the bolt pre-tightening force according to the bolt tightening sequence in Step 3; 52) After calculation and analysis, record the pressure F on the contact surface after applying the pre-tightening force of the adjusting bolt 6 N5 and the pressure F on the contact surface after applying the pre-tightening force of the four fixing bolts N6 ; Calculate the corresponding frictional resistance F f5 and F f6 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3) f3 .

6. The method for analyzing the adjustment friction resistance of a steering column tube according to claim 5, characterized in that, The specific method of Step 7 is as follows: 71) Apply the bolt pre-tightening force according to the bolt tightening sequence in Step 3; 72) After calculation and analysis, record the pressure F on the contact surface after applying the pre-tightening force of the adjusting bolt 6 N7 and the pressure F on the contact surface after applying the pre-tightening force of the four fixing bolts N8 ; Calculate the corresponding frictional resistance F f7 and F f8 according to formula (2), and then calculate the change ΔF of the frictional resistance using formula (3) f4 .

7. A method for analyzing the adjustment friction resistance of a steering column tube according to claim 5, characterized in that, The specific method of Step 8 is as follows: 81) Calculate the change in frictional resistance ΔF using formula (4). f3 and ΔF f4 The percentage changes δ1 and δ2 relative to ΔF f2 are calculated. where n = 1, 2, 3, ……, δ n is the percentage change in the change amount of the frictional resistance; 82) If δ1 ≤ 5% and δ2 ≤ 5%, it is considered that the deformation of the bracket caused during the preloading process has no effect on the adjustment friction resistance of the steering column tube; otherwise, it is considered that the deformation of the bracket caused during the preloading process affects the smoothness of the steering column tube adjustment, and the bracket structure needs to be adjusted.

8. An analysis device for the adjustment friction resistance of a steering column tube, characterized in that, including a modeling module for establishing a finite element model of the steering column tube and the bracket; a definition module for defining contact and boundary conditions and defining the material properties of the finite element model, including defining the material elastic modulus and Poisson's ratio, and using linear elastic material properties in the analysis; a first calculation module for applying bolt preloading force, recording the pressure on the contact surface, and obtaining the friction resistance of the contact surface; applying a steering column adjustment load, recording the pressure on the contact surface, and calculating the change value of the friction resistance; and sequentially applying bolt preloading forces in the order of bolt numbers and calculating the change value of the friction resistance; a first adjustment module for adjusting the unevenness of the bracket at the third bolt; a second calculation module for sequentially applying bolt preloading forces in the order of bolt numbers and calculating the change value of the friction resistance; a second adjustment module for adjusting the unevenness of the bracket at the fourth bolt; a third calculation module for sequentially applying bolt preloading forces in the order of bolt numbers and calculating the change value of the friction resistance; a judgment module for comparing the change in the contact surface friction resistance and judging the influence on the adjustment friction resistance of the steering column tube based on the change in the contact surface friction resistance.

9. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements a method for analyzing the adjustment friction resistance of a steering column tube as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements a method for analyzing the adjustment friction resistance of a steering column tube as described in any one of claims 1-7.

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