Tire bead ring mechanical property testing device and property evaluation method

Abstract

According to the tire steel wire ring mechanical property testing device and the performance evaluation method, the tire steel wire ring is subjected to a loading experiment through the tire steel wire ring mechanical property testing device, mechanical data in the testing process are obtained through a signal measuring and collecting system, and mechanical parameters are obtained through mechanical model analysis; the performance of the steel wire ring is analyzed and evaluated to obtain the breaking strength, the deformation condition, the circumferential rigidity, the radial rigidity and the like of the tire steel wire ring, a scientific basis is provided for the matching design of the tire bead and the rim, the tire is prevented from transposition, and meanwhile the steel wire ring is prevented from being broken due to the too large interference magnitude of the tire bead and the rim.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tires, and particularly relates to a tire bead mechanical property testing device and an evaluation method. BACKGROUND

[0002] During braking of an airplane or a vehicle, the tire and the rim will rotate relative to each other to a certain extent, which is referred to as rotation. The rotation problem can cause the tire to leak and even to be damaged. In order to avoid the rotation problem between the tire and the rim, a common method in the industry is to increase the interference amount between the tire bead and the rim, increase the clamping force of the tire bead on the rim, and thus increase the friction between the tire and the rim to avoid the rotation problem. However, in actual situations, this can increase the risk of rupture of the tire bead and reduce the reliability of the tire bead. Therefore, a tire bead mechanical property testing device and a corresponding evaluation method are needed. SUMMARY

[0003] To solve the above technical problems, the application provides a tire bead mechanical property testing device and an evaluation method. The tire bead is subjected to a loading experiment by using the tire bead mechanical property testing device, the required mechanical parameters in the testing process are obtained by using a force measuring module and a displacement measuring module, a mechanical model is established to analyze and evaluate the above mechanical parameters, and the breaking strength, stiffness and other mechanical properties of the tire bead in the service process are obtained. The application obtains the ultimate bearing capacity of the tire bead and the mechanical properties such as the hoop stiffness and the radial stiffness of the tire bead by experimental measurement and theoretical methods, provides a scientific basis for the design of the interference amount between the tire bead and the rim, avoids the rotation of the tire, and prevents the rupture of the tire bead caused by the excessive interference amount between the tire bead and the rim.

[0004] To achieve the above purpose, the application adopts the following technical solutions:

[0005] A tire bead mechanical property testing device, comprising:

[0006] A device bottom plate for placing the entire device structure;

[0007] A bottom actuator for providing vertical lift;

[0008] A bottom support column for supporting an upper loading and measuring system;

[0009] A device middle plate for installing an instrument lower slide rail and placing an upper structure;

[0010] An upper support column for supporting a device top plate;

[0011] The device top plate is used for installing an instrument upper slide rail.

[0012] a center loading device coaxially arranged with the bottom actuator and driven upward by the lifting force;

[0013] a plurality of transmission devices evenly distributed around the center loading device and synchronously sliding outward when the center loading device moves upward;

[0014] a plurality of arc-shaped clamping devices correspondingly arranged outside the transmission devices and expanding radially outward with the outward movement of the transmission devices to exert radial thrust on the steel wire ring clamped on the periphery of each arc-shaped clamping device;

[0015] a force measuring module arranged between each transmission device and the corresponding arc-shaped clamping device for real-time acquisition of the thrust;

[0016] a displacement measuring module arranged opposite to the arc-shaped clamping device for real-time acquisition of the radial displacement of the steel wire ring;

[0017] an upper slide rail and a lower slide rail respectively constraining the upper and lower end faces of the arc-shaped clamping device so that it can only move radially in the horizontal plane; the vertical lifting force of the bottom actuator is converted into radial thrust acting on the steel wire ring through the center loading device, the transmission device and the arc-shaped clamping device, and the synchronous acquisition of thrust and radial displacement is completed simultaneously in the process.

[0018] Further, the center loading device is an n-sided prism, and the transmission device and the arc-shaped clamping device are each n groups, and the n groups of arc-shaped clamping devices form a complete circle to uniformly exert radial load on the steel wire ring in an n-point synchronous manner.

[0019] Further, the force measuring module and the displacement measuring module output the thrust signal and the radial displacement signal collected at the same time in pairs for subsequent direct calculation of the hoop force, hoop deformation and stiffness of the steel wire ring according to the preset mechanical model.

[0020] The application also provides a method for evaluating the mechanical properties of a tire steel wire ring, comprising the following steps:

[0021] Step 1: applying radial thrust to the steel wire ring using the above-mentioned tire steel wire ring mechanical property testing device, and synchronously acquiring the total hoop tightening force, radial displacement and the number of arc-shaped clamping devices;

[0022] Step 2: determining the hoop force of the cross section of the steel wire ring according to the total hoop tightening force and the number of arc-shaped clamping devices according to the preset cross section force evaluation method;

[0023] Step 3: converting the radial displacement into hoop deformation according to the geometric relationship, and calculating the equivalent strain according to the ratio of the hoop deformation to the initial circumference of the steel wire ring;

[0024] Step 4, the equivalent strain is substituted into the nonlinear evaluation criterion with the number of arc-shaped clamping devices changing to obtain the real strain of the bead when the actual tire is assembled on the rim;

[0025] Step 5, the equivalent elastic modulus of the bead is calculated according to the hoop force, the real strain and the known cross-sectional area;

[0026] Step 6, the hoop stiffness is determined according to the ratio of the hoop force to the hoop deformation at the same time, and the radial stiffness is determined according to the ratio of the total hoop force to the radial displacement at the same time;

[0027] Step 7, the hoop force, the equivalent strain, the real strain, the equivalent elastic modulus, the hoop stiffness and the radial stiffness are comprehensively output to complete the mechanical property evaluation of the bead.

[0028] Further, the cross-sectional force conversion rule in step 2 is that the total hoop force is divided by the product of twice the number of arc-shaped clamping devices and the sine value of π / n radian to obtain the hoop force, wherein n is the number of arc-shaped clamping devices.

[0029] Further, the nonlinear proportionality coefficient in step 4 monotonically decreases with the increase of the number of arc-shaped clamping devices, and when the number increases from 2 to 100, the proportionality coefficient continuously decreases, and the real strain is directly obtained by multiplying the equivalent strain by the coefficient.

[0030] Further, in step 5, the equivalent elastic modulus is calculated according to the quotient of the hoop force and the cross-sectional area, the real strain, and the modulus is output as a homogeneous material parameter for subsequent finite element modeling.

[0031] Further, in step 6, the hoop stiffness curve is continuously calculated and output according to the ratio of the hoop force increment to the hoop deformation increment in the continuous loading process, and the radial stiffness curve is continuously calculated and output according to the ratio of the total hoop force increment to the radial displacement increment.

[0032] Further, the hoop force obtained in step 2 is divided by the cross-sectional area to obtain the cross-sectional stress, and the real strain obtained in step 4 is taken as the abscissa and the cross-sectional stress is taken as the ordinate to draw the stress-strain curve point by point, which is used for directly selecting the service interval of the bead.

[0033] Further, when the number of arc-shaped clamping devices tends to infinity, the hoop force is the quotient of the total hoop force and 2π, the real strain is equal to the equivalent strain, and the hoop force, the real strain and the equivalent elastic modulus in the limit state are directly output as the theoretical boundary values.

[0034] Beneficial effects:

[0035] 1. The present application drives the intermediate loading device by the bottom actuator, drives the arc clamping device by the peripheral transmission device to load the tire bead, so that the lifting force of the bottom actuator is converted into horizontal plane thrust, and the test range of the present application is large, and the types of the beads that can be detected are extensive.

[0036] 2. The present application can obtain the size of the hoop force of the bead in the horizontal plane during the test process through the force measuring module, and obtain the real-time radial deformation of the bead during the test process through the displacement measuring module, and according to the proposed mechanical performance evaluation method of the tire bead, the cross-sectional force and the hoop deformation of the tire bead are obtained, so as to comprehensively evaluate the mechanical performance of the tire bead.

[0037] 3. The present application can accurately calculate the cross-sectional strength of the tire bead through the proposed mechanical model, convert the hoop force of the bead in the horizontal plane obtained by the force measuring module into the hoop force on the cross section of the tire bead, and accurately evaluate the ultimate strength of the tire bead when the tire bead is loaded and destroyed, thereby providing a scientific basis for the interference design of the tire and the rim.

[0038] 4. The present application can convert the equivalent strain of the bead measured by the bead mechanical performance testing device into the real strain of the tire bead when the tire is assembled on the rim, so as to avoid the influence of the number of arc clamping devices on the real strain of the tire bead obtained by the bead mechanical performance testing device, and thus the mechanical parameters obtained by the present application can be used to scientifically and reasonably evaluate the mechanical performance of the tire bead.

[0039] 5. The present application regards the tire bead as a structure composed of a homogeneous material, and based on the second point and the proposed mechanical model, the cross-sectional stress and the real strain of the tire bead are obtained, so as to obtain the mechanical performance evaluation index of the homogeneous material, so that the winding structure of the bead is no longer considered when performing finite element modeling analysis, the problem of non-convergence caused by the contact analysis of the steel wire winding is avoided, and the difficulty of finite element whole tire simulation is greatly reduced.

[0040] 6. Based on the above fifth point, the present application can obtain the stress and real strain relationship curve of the tire bead, so as to select the service interval of the bead according to the different mechanical performance sections of the bead, so as to maximize the mechanical performance of the bead, and ensure the structural safety of the bead in the actual processing process.

[0041] 7. Based on the second point, the relationship between the bead ring hoop force and the hoop deformation can be obtained, and the relationship between the radial pressure of the arc-shaped clamping device on the bead ring and the radial displacement of the bead ring can also be obtained, so that the quantitative evaluation criterion of the bead ring stiffness is obtained, which is beneficial to guiding the evaluation of the winding structure design of the bead ring, the interference amount design of the tire and the rim, and the subsequent evaluation analysis of the finite element simulation research of the tire. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A schematic diagram of a tire bead mechanical property testing device provided by an embodiment of the present application is shown in the figure.

[0043] Figure 2 A cross-sectional detail view of an upper loading and measuring module of a tire bead mechanical property testing device provided by an embodiment of the present application is shown in the figure.

[0044] Figure 3 A working principle schematic diagram of a tire bead mechanical property testing device provided by an embodiment of the present application is shown in the figure.

[0045] Figure 4 A mechanical model schematic diagram of a tire bead mechanical property evaluation method provided by an embodiment of the present application when the number of arc-shaped clamping devices is n is shown in the figure. The left figure is a front view, and the right figure is an enlarged view of B of the left figure.

[0046] Figure 5 A mechanical model schematic diagram of a tire bead mechanical property evaluation method provided by an embodiment of the present application when the number of arc-shaped clamping devices is n = 6 is shown in the figure. The left figure is a front view, and the right figure is an enlarged view of C of the left figure.

[0047] Figure 6 A nonlinear proportional relationship schematic diagram of a strain proportional coefficient of a tire bead mechanical property evaluation method provided by an embodiment of the present application with the increase of the number of arc-shaped clamping devices is shown in the figure.

[0048] Figure 7 A bead ring hoop stiffness curve schematic diagram collected by a tire bead mechanical property testing device provided by an embodiment of the present application is shown in the figure.

[0049] Figure 8 A bead ring radial stiffness curve schematic diagram collected by a tire bead mechanical property testing device provided by an embodiment of the present application is shown in the figure.

[0050] Figure 9 A bead ring stress-strain relationship curve schematic diagram collected by a tire bead mechanical property testing device provided by an embodiment of the present application is shown in the figure.

[0051] Wherein, the reference signs are: 1-device bottom plate, 2-actuator, 3-bottom support column, 4-device middle plate, 5-upper support column, 6-device top plate, 7-upper slide rail, 8-center loading device, 9-transmission device, 10-force measurement module, 11-arc-shaped clamping device, 12-lower slide rail, 13-displacement measurement module, 14-bottom actuator force, 15-steel ring mechanical model, 16-arc-shaped clamping device mechanical model, 17-transmission device pressure mechanical model. DETAILED DESCRIPTION

[0052] To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical methods in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present application.

[0053] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship between components, movement conditions, etc. in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0054] As shown in Figure 1 , Figure 2 , a tire steel ring mechanical property testing device of the present application comprises:

[0055] A device bottom plate 1 is used to place the entire device structure.

[0056] A bottom actuator 2 is used to provide vertical lift.

[0057] A bottom support column 3 is used to support the upper loading and measurement system.

[0058] A device middle plate 4 is used to install the instrument lower slide rail 12 and place the upper structure.

[0059] An upper support column 5 is used to support the device top plate 6.

[0060] A device top plate 6 is used to install the instrument upper slide rail 7.

[0061] A center loading device 8 is coaxially arranged with the bottom actuator and is driven by the lift to move upward.

[0062] A plurality of transmission devices 9 are evenly distributed around the center loading device and synchronously slide outward when the center loading device moves upward.

[0063] A plurality of arc-shaped clamping devices 11 are arranged on the outside of the transmission device one by one, and expand radially outward with the outward movement of the transmission device to exert a radial pushing force on the steel wire ring clamped on the periphery of each arc-shaped clamping device;

[0064] A force measuring module 10 is arranged between each transmission device and the corresponding arc-shaped clamping device for real-time acquisition of the pushing force;

[0065] A displacement measuring module 13 is arranged opposite the arc-shaped clamping device for real-time acquisition of the radial displacement of the steel wire ring;

[0066] The upper slide rail 7 and the lower slide rail 12 constrain the upper and lower end faces of the arc-shaped clamping device respectively, so that it can only move radially in the horizontal plane; the vertical lifting force of the bottom actuator is converted into a radial pushing force acting on the steel wire ring through the center loading device, the transmission device and the arc-shaped clamping device, and the synchronous acquisition of the pushing force and the radial displacement is completed synchronously in the process.

[0067] The transmission device 9, the force measuring module 10, the arc-shaped clamping device 11 are radially connected together, clamped between the upper slide rail 7 and the lower slide rail 12, and the displacement measuring module 13 is arranged opposite the arc-shaped clamping device 11.

[0068] The loading system is composed of the upper slide rail 7, the center loading device 8, the transmission device 10, the arc-shaped clamping device 11 and the lower slide rail 12, and is driven by the bottom actuator to push the intermediate loading device upward, drive the peripheral transmission device to push the arc-shaped clamping device to load the steel wire ring, so that the lifting force of the bottom actuator is converted into a pushing force in the horizontal plane, and the lifting force of the actuator is amplified at the same time.

[0069] The force measuring module obtains the pushing force of the arc-shaped clamping device 11 on the steel wire ring through the force measuring module 10 between the transmission device 10 and the arc-shaped clamping device 11, that is, the force measuring module acquires the pressure of the transmission device on the arc-shaped clamping device in real time, so as to realize the acquisition of the loading force value of the steel wire ring in the horizontal plane, and the total tightening force of the tire steel wire ring The calculation formula is:

[0070] (1)

[0071] In the formula, is the force value of each force measuring module (unit: kN), n is the number of arc-shaped clamping devices, and m is the index value.

[0072] The displacement measuring module 13 is installed at the position opposite the arc-shaped clamping device 11, and the radial deformation of the steel wire ring can be measured by loading the steel wire ring through the n arc-shaped clamping devices 11, and the hoop deformation of the entire steel wire ring can be obtained and equivalent strain The radial deformation, circumferential deformation, and equivalent strain of the wire ring are as follows:

[0073] = (2)

[0074] (3)

[0075] (4)

[0076] In the formula, The number of arc-shaped clamping devices, The specific formula for the average radius (in mm) of the wire coil is as follows: (5)

[0077] In the formula, This is the inner radius of the wire loop (in mm). The radius of the cross-section of the wire loop is in mm.

[0078] This invention also provides a method for evaluating the mechanical properties of tire steel wire rings. Figure 4 The schematic diagram of the mechanical model in the evaluation method specifically includes:

[0079] This invention proposes a mechanical model for evaluating the cross-sectional strength of tire steel wire rings based on mechanical principles, such as... Figure 4 As shown, Figure 4 In this context, A represents one-nth of the entire mechanical model. Within A... For the cross-sectional force of the wire coil, The radial component of the force on the cross section of the wire coil. This is the component of the force perpendicular to the radial direction of the wire coil. The radial thrust is collected by the force measurement module, and θ is π divided by the number of arc-shaped clamping devices n.

[0080] The circumferential force of the wire ring cross section can be accurately calculated, thereby obtaining the ultimate strength of the wire ring at failure and enabling precise evaluation of the failure strength of the wire ring. The formula for calculating the force of the wire ring cross section is as follows:

[0081] (6)

[0082] In the formula, Let n be the circumferential force on the cross section of the wire ring.

[0083] This invention proposes a nonlinear evaluation criterion for converting the equivalent strain of the steel wire ring obtained from a tire steel wire ring mechanical performance testing device into the actual strain of the steel wire ring during the actual tire and rim assembly process. The specific nonlinear evaluation criterion is as follows:

[0084] (7)

[0085] wherein:

[0086] (8)

[0087] wherein, is a strain ratio coefficient, is an equivalent strain of the steel wire ring loaded by the n arc-shaped clamping devices, is a real strain of the steel wire ring in the actual processing process.

[0088] The present application regards the tire steel wire ring as a homogeneous material, and evaluates and analyzes the mechanical property of the homogeneous material to obtain a quantitative evaluation result, and the formula of the equivalent elastic modulus of the homogeneous material is:

[0089] (9)

[0090] wherein, is a cross-sectional area of the steel wire ring, and specifically is: , is a total clamping force received by the tire steel wire ring, and is specifically obtained from the formula (1).

[0091] The present application proposes an evaluation method of the stiffness of the tire steel wire ring based on the displacement measurement module, the force measurement module and the proposed mechanical model, which is convenient for subsequent finite element true research work of the tire, and the evaluation method of the circumferential stiffness of the steel wire ring is obtained according to the relationship between the circumferential force of the steel wire ring and the circumferential deformation.

[0092] (10)

[0093] wherein:

[0094] (11)

[0095] wherein, is an equivalent elastic modulus of the steel wire ring regarded as a homogeneous material, is a circumferential deformation amount (unit: mm) of the steel wire ring, is an average radius (unit: mm) of the steel wire ring, is a cross-sectional area of the steel wire ring.

[0096] Meanwhile, the radial stiffness evaluation method of the steel wire ring can also be obtained according to the relationship between the pressure of the arc-shaped clamping device on the steel wire ring and the radial deformation of the steel wire ring.

[0097] (12) ​​

[0098] in:

[0099] (13)

[0100] In the formula, This is the radial stiffness evaluation coefficient; the other parameters are the same as above.

[0101] In one embodiment of the present invention, the tire wire bead mechanical performance testing device of the present invention is exemplified by six arc-shaped clamping devices 11, such as... Figure 1 As shown. Figure 2 As shown, it contains six transmission devices 9, with a central loading device 8 in the shape of a hexagonal prism. An arc-shaped clamping device 11 clamps the tire wire ring through a groove in the center. The testing device uses a bottom actuator 2 to apply an upward force 14 to the central hexagonal prism, pushing the surrounding transmission devices 9, thereby causing the outermost arc-shaped clamping device 11 to expand the wire ring outwards until it is damaged by the load. Figure 3 As shown, during the entire loading process, the force measurement module 10 records in real time the force applied by the transmission device 9 to the arc-shaped clamping transducer 11, i.e. the pressure on the wire ring, while the displacement measurement module 13 monitors in real time the displacement of the arc-shaped clamping device 11, i.e. the expansion of the wire ring.

[0102] In one embodiment of the present invention, a mechanical model for evaluating the cross-sectional strength of tire steel wire rings is proposed based on a testing device with n arc-shaped clamping devices, such as... Figure 4 As shown, the circumferential force of the wire ring cross section can be accurately calculated, enabling precise evaluation of the ultimate strength of the wire ring. Figure 4 In the model, the steel wire ring mechanical model 15 is the model of the steel wire ring clamped during actual test loading; the arc-shaped clamping device mechanical model 16 is the model of the arc-shaped clamping device 11 of the test device; and the force transmission device pressure mechanical model 17 is the model of the pressure of the transmission device 9 collected by the force measurement module 10 during the loading process of the test device. Selecting a fraction B (n-th percentile) of the entire mechanical model for force analysis, the formula for calculating the cross-sectional strength of the tire steel wire ring can be obtained:

[0103] (6)

[0104] When the number of arc-shaped clamping devices n=6, as follows Figure 5 As shown, according to equation (6), the magnitude of the cross-sectional force of the wire ring is:

[0105] ;

[0106] In one embodiment of the present invention, taking a tire steel wire ring equipped with six arc-shaped clamping devices 11 as an example, the ultimate strength of the steel wire ring is calculated. When the steel wire ring is damaged by loading, the values ​​measured by each force measuring module are as follows: , , , , , Then the total clamping force of the wire ring in the plane at this time is:

[0107] ;

[0108] According to formula (6), the ultimate strength of the wire ring is ( ):

[0109] ;

[0110] In the formula, The destructive force of the wire ring section when there are 6 arc-shaped push blocks (in kN).

[0111] When the tire's steel wire bead is damaged by loading Substituting into the above formula, the ultimate strength of the steel wire ring can be obtained as follows:

[0112] ;

[0113] In one embodiment of the present invention, the steel wire ring is loaded using n arc-shaped clamping devices to obtain the real-time strain change of the steel wire ring. Using the nonlinear evaluation criterion between the experimentally measured strain and the actual strain proposed in this invention, the actual strain of the steel wire ring during actual processing can be obtained. The specific evaluation criterion is as follows:

[0114] (7)

[0115] Where A is the nonlinear proportionality coefficient:

[0116] (8)

[0117] When the number of arc-shaped clamping devices (n) increases from 2 to 100, the nonlinear proportional relationship between the strain proportionality coefficient and the increase in the number of arc-shaped clamping devices is as follows: Figure 6 As shown. Figure 6 In the diagram, A2 is the magnitude of the nonlinear proportionality coefficient A when the number of arc-shaped clamping devices n=2. n It is the magnitude of the nonlinear proportional coefficient A when the number of arc-shaped clamping devices is n.

[0118] In an embodiment of the present application, the intermediate loading device is pushed upward by the actuator at the bottom of the tire bead mechanical property testing device, which drives the transmission to push the arc-shaped clamping device to load the bead. Taking the configuration of six arc-shaped clamping devices as an example, the pushing force of each arc-shaped clamping device on the bead and the radial displacement of the bead during loading are obtained through the force measuring module and the displacement measuring module. According to formula (9), when n=6, we have:

[0119] ;

[0120] In an embodiment of the present application, taking the tire bead mechanical property testing device with six arc-shaped clamping devices as an example, when n=6, substituting into formula (11) gives:

[0121] ;

[0122] The tire bead mechanical property testing instrument with six arc-shaped clamping devices obtained by actual processing is used to conduct loading test on the bead, and the hoop stiffness curve of the tire bead is obtained as shown in Figure 7 .

[0123] When n=6, substituting into formula (13) gives:

[0124] ;

[0125] The tire bead mechanical property testing instrument with six arc-shaped clamping devices obtained by actual processing is used to conduct loading test on the bead, and the radial stiffness curve of the bead is obtained as shown in Figure 8 .

[0126] In an embodiment of the present application, taking the tire bead mechanical property testing device with six arc-shaped clamping devices 11 as an example, according to the relationship between the cross-sectional stress and the true strain of the tire bead, we have:

[0127] (14)

[0128] Wherein:

[0129] ;

[0130] ;

[0131] The tire bead mechanical property testing instrument with six arc-shaped clamping devices obtained by actual processing is used to conduct loading test on the bead, and the cross-sectional stress and the true strain of the tire bead are obtained, and thus the stress-strain curve of the cross section of the tire bead is obtained as shown in Figure 9As shown, according to the stress-strain curve, a reasonable interference can be selected in designing the tire, so that the steel bead in the tire can fully play the mechanical properties during service, and meanwhile the structural safety thereof is ensured. Figure 9 In the formula, σ is the cross-section stress of the tire steel bead obtained through the test, and ε is the true strain of the steel bead obtained through the test and the nonlinear evaluation criterion

[0132] In one possible embodiment of the present application, the present application provides a tire steel bead mechanical property testing device and evaluation method. When the number of arc-shaped clamping devices is According to the formula (1), the total hoop force of the steel bead can be obtained even if more than 6 arc-shaped clamping devices are used to load the tire steel bead.

[0133] According to the calculation formula (6) of the cross-section strength of the steel bead, the following equation can be obtained:

[0134] .

[0135] Those skilled in the art will easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.​

Claims

1. A device for testing the mechanical properties of tire steel wire rings, characterized in that, include: Bottom actuator, used to output vertical lift; The central loading device is coaxially arranged with the bottom actuator and is driven upward by the lifting force. Several transmission devices are evenly distributed around the central loading device and slide outward synchronously when the central loading device moves upward; Several arc-shaped clamping devices are arranged one by one on the outside of the transmission device, and expand radially outward as the transmission device moves outward, so as to apply radial thrust to the wire rings clamped on the outer periphery of each arc-shaped clamping device. A force measurement module is located between each transmission device and the corresponding arc-shaped clamping device to collect the thrust in real time. The displacement measurement module is arranged opposite the arc-shaped clamping device and is used to collect the radial displacement of the wire ring in real time. The upper and lower slide rails respectively constrain the upper and lower end faces of the arc-shaped clamping device, allowing it to move radially only in the horizontal plane. The vertical lift of the bottom actuator is converted into a radial thrust acting on the wire ring through the central loading device, transmission device, and arc-shaped clamping device, and the thrust and radial displacement are synchronously collected during this process.

2. The tire steel wire bead mechanical performance testing device according to claim 1, characterized in that, The central loading device is an n-sided prism, and there are n sets of transmission devices and arc-shaped clamping devices. The n sets of arc-shaped clamping devices together form a complete circle, applying a uniform radial load to the wire ring in a synchronous manner at n points.

3. A tire steel wire bead mechanical performance testing device according to claim 1 or 2, characterized in that, The force measurement module and displacement measurement module output the thrust signal and radial displacement signal collected at the same time in pairs, which are used to directly calculate the circumferential force, circumferential deformation and stiffness of the wire ring according to the preset mechanical model.

4. A method for evaluating the mechanical properties of tire steel wire rings, characterized in that, Includes the following steps: Step 1: Apply radial thrust to the tire wire ring using the mechanical performance testing device described in any one of claims 1-3, and simultaneously collect the total clamping force, radial displacement, and number of arc-shaped clamping devices; Step 2: Based on the total clamping force and the number of arc-shaped clamping devices, determine the circumferential force of the wire ring section according to the preset section force evaluation method; Step 3: Convert the radial displacement into circumferential deformation according to geometric relationships, and calculate the equivalent strain based on the ratio of circumferential deformation to the initial circumference of the wire ring; Step 4: Substitute the equivalent strain into the nonlinear evaluation criterion that varies with the number of arc-shaped clamping devices to obtain the true strain of the wire ring when the actual tire is assembled onto the rim. Step 5: Calculate the equivalent elastic modulus of the wire loop using the circumferential force, actual strain, and known cross-sectional area. Step 6: Determine the circumferential stiffness by the ratio of circumferential force to circumferential deformation at the same moment, and determine the radial stiffness by the ratio of total clamping force to radial displacement at the same moment. Step 7: Output the circumferential force, equivalent strain, true strain, equivalent elastic modulus, circumferential stiffness, and radial stiffness to complete the mechanical performance evaluation of the steel wire ring.

5. The method for evaluating the mechanical properties of tire steel wire rings according to claim 4, characterized in that, The cross-sectional force conversion rule in step 2 is to divide the total clamping force by the product of twice the number of arc-shaped clamping devices and the sine value of π / n radians to obtain the circumferential force, where n is the number of arc-shaped clamping devices.

6. The method for evaluating the mechanical properties of tire steel wire rings according to claim 4, characterized in that, The nonlinear proportional coefficient mentioned in step 4 decreases monotonically as the number of arc-shaped clamping devices increases. When the number increases from 2 to 100, the proportional coefficient decreases continuously. The true strain is obtained by directly multiplying the equivalent strain by the coefficient.

7. The method for evaluating the mechanical properties of tire steel wire rings according to claim 4, characterized in that, In step 5, the equivalent elastic modulus is calculated by the quotient of circumferential force, cross-sectional area, and true strain, and this modulus is output as a parameter of the homogeneous material for subsequent finite element modeling.

8. The method for evaluating the mechanical properties of tire steel wire rings according to claim 7, characterized in that, In step 6, during the continuous loading process, the circumferential force and circumferential deformation of the wire ring at each moment are obtained through the signal measurement and acquisition system and the mechanical model, and the circumferential stiffness curve of the wire ring is output. At the same time, the radial force and radial deformation of the wire ring at each moment are obtained, and the radial stiffness curve of the wire ring is output.

9. The method for evaluating the mechanical properties of tire steel wire rings according to claim 8, characterized in that, Divide the circumferential force obtained in step 2 by the cross-sectional area to obtain the cross-sectional stress. Use the actual strain obtained in step 4 as the abscissa and the cross-sectional stress as the ordinate to plot the stress-strain curve point by point, which can be used to directly select the service range of the wire coil.

10. The method for evaluating the mechanical properties of tire steel wire rings according to claim 9, characterized in that, When the number of arc-shaped clamping devices approaches infinity, the circumferential force is taken as the quotient of the total clamping force and 2π, and the actual strain and equivalent strain are equal. The circumferential force, actual strain and equivalent elastic modulus under this limit state are directly used as the theoretical boundary values ​​for output.

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