Tire bead mechanical property testing device and performance evaluation method

Abstract

The application provides a tire bead mechanical property testing device and a performance evaluation method. The tire bead is subjected to a loading experiment through the tire bead mechanical property testing device. The signal measurement and acquisition system is used to obtain mechanical data in the testing process. The mechanical model analysis is used to obtain mechanical parameters. The performance of the bead is analyzed and evaluated. The breaking strength, deformation, hoop stiffness and radial stiffness of the tire bead are obtained. A scientific basis is provided for the matching design of the tire bead and the rim. The tire is prevented from being turned. The bead is prevented from being broken due to the excessive interference between the bead and the rim.

Description

Technical Field

[0001] This invention belongs to the field of tire technology, specifically relating to a device and evaluation method for testing and evaluating the mechanical properties of tire steel wire rings. Background Technology

[0002] During aircraft and automobile braking, the tire and rim rotate to varying degrees, a process known as tire rotation. Rotation can cause dangers such as tire leaks and blowouts. To avoid this, the industry commonly uses increasing the interference fit between the tire bead and the rim, thus increasing the clamping force exerted on the rim by the steel wire ring in the tire, thereby enhancing the friction between the tire and the rim and preventing rotation. However, in practice, this increases the risk of steel wire ring breakage and reduces the reliability of the tire steel wire ring. Therefore, a device for testing the mechanical properties of tire steel wire rings and corresponding evaluation methods are needed. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a testing device and evaluation method for the mechanical properties of tire bead rings. The device performs loading experiments on tire bead rings, utilizing force and displacement measurement modules to obtain the required mechanical parameters during the test. A mechanical model is then established to analyze and evaluate these parameters, yielding the tire bead ring's breaking strength, stiffness, and other mechanical properties during service. This invention, through experimental measurements and theoretical methods, obtains the ultimate load-bearing capacity of tire bead rings, as well as their circumferential and radial stiffness, providing a scientific basis for designing the interference fit between the tire bead and rim. This prevents tire rotation and avoids bead ring breakage due to excessive interference fit between the bead and rim.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A device for testing the mechanical properties of tire steel wire rings includes:

[0006] The base plate of the device is used to support the entire device structure.

[0007] Bottom actuators are used to provide vertical lift;

[0008] Bottom support pillars are used to support the upper loading and measurement system;

[0009] The middle plate of the device is used to install the lower rail of the instrument and to house the upper structure.

[0010] The upper support column is used to support the top plate of the device;

[0011] The top plate of the device is used to mount the upper slide rail of the instrument.

[0012] The central loading device is coaxially arranged with the bottom actuator and is driven upward by the lifting force.

[0013] Several transmission devices are evenly distributed around the central loading device and slide outward synchronously when the central loading device moves upward;

[0014] 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.

[0015] A force measurement module is located between each transmission device and the corresponding arc-shaped clamping device to collect the thrust in real time.

[0016] 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.

[0017] 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.

[0018] Furthermore, 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.

[0019] Furthermore, the force measurement module and the 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.

[0020] This invention also provides a method for evaluating the mechanical properties of tire steel wire rings, comprising the following steps:

[0021] Step 1: Apply radial thrust to the tire wire ring using the above-mentioned tire wire ring mechanical performance testing device, and simultaneously collect the total clamping force, radial displacement, and number of arc-shaped clamping devices.

[0022] 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;

[0023] 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;

[0024] 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.

[0025] Step 5: Calculate the equivalent elastic modulus of the wire loop using the circumferential force, actual strain, and known cross-sectional area.

[0026] 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.

[0027] 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.

[0028] Furthermore, 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.

[0029] Furthermore, 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, and the true strain is obtained by directly multiplying the equivalent strain by the coefficient.

[0030] Furthermore, 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.

[0031] Furthermore, in step 6, the circumferential stiffness curve is continuously calculated and output based on the ratio of the circumferential force increment to the circumferential deformation increment between two adjacent stages during continuous loading; and the radial stiffness curve is continuously calculated and output based on the ratio of the total clamping force increment to the radial displacement increment between two adjacent stages.

[0032] Furthermore, the circumferential force obtained in step 2 is divided by the cross-sectional area to obtain the cross-sectional stress. The actual strain obtained in step 4 is used as the abscissa and the cross-sectional stress as the ordinate. The stress-strain curve is plotted point by point to directly select the service range of the wire coil.

[0033] Furthermore, 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 theoretical boundary values ​​for output.

[0034] Beneficial effects:

[0035] 1. This invention uses a bottom actuator to drive an intermediate loading device, which in turn drives a peripheral transmission device to push an arc-shaped clamping device to load the tire steel wire ring. This converts the lift force of the bottom actuator into a horizontal thrust force, which is amplified to perform mechanical performance tests on high-strength tire steel wire rings. This invention has a large testing range and can test a wide variety of steel wire rings.

[0036] 2. This invention can obtain the magnitude of the clamping force in the horizontal plane of the tire wire ring during the test through the force measurement module, obtain the real-time radial deformation of the tire wire ring during the test through the displacement measurement module, and obtain the cross-sectional force and circumferential deformation of the tire wire ring according to the proposed tire wire ring mechanical performance evaluation method, so as to comprehensively evaluate the mechanical performance of the tire wire ring.

[0037] 3. The mechanical model proposed in this invention can accurately calculate the cross-sectional strength of the tire steel wire ring, and convert the clamping force in the horizontal plane of the steel wire ring obtained by the force measurement module into the circumferential force on the cross-section of the tire steel wire ring. This allows for an accurate evaluation of the ultimate strength of the tire steel wire ring under load failure, providing a scientific basis for the interference fit design of tires and rims.

[0038] 4. The mechanical model proposed in this invention can convert the equivalent strain of the steel wire ring measured by the steel wire ring mechanical performance testing device into the actual strain of the tire steel wire ring when the tire is actually assembled onto the rim. This can avoid the influence of the number of arc-shaped clamping devices on the final obtained true strain of the tire steel wire ring in the steel wire ring mechanical performance testing device. Therefore, the mechanical performance of the tire steel wire ring can be scientifically and reasonably evaluated based on the mechanical parameters obtained according to this invention.

[0039] 5. This invention treats the tire wire bead as a structure composed of a homogeneous material. Based on point 2 and the proposed mechanical model, the cross-sectional stress and actual strain of the tire wire bead are obtained, thereby obtaining the mechanical performance evaluation index of the homogeneous material. In this way, the winding structure of the wire bead is no longer considered when performing finite element modeling analysis, avoiding the non-convergence problem of contact analysis caused by the winding contact of the wires, and greatly reducing the difficulty of finite element whole tire simulation.

[0040] 6. Based on point 5 above, this invention can obtain the relationship curve between stress and actual strain of the tire wire ring, thereby selecting the service range of the wire ring according to different mechanical performance ranges, thus maximizing the mechanical performance of the wire ring and ensuring the structural safety of the wire ring during actual processing.

[0041] 7. Based on point 2, this invention can obtain the relationship between the circumferential force and circumferential deformation of the wire coil, as well as the relationship between the radial pressure of the arc-shaped clamping device on the wire coil and the radial displacement of the wire coil. This allows for the acquisition of a quantitative evaluation criterion for the stiffness of the wire coil, which is beneficial for guiding and evaluating the design of the wire coil winding structure, the interference fit design between the tire and the rim, and for subsequent evaluation and analysis of the tire through finite element simulation studies. Attached Figure Description

[0042] Figure 1 A schematic diagram of a tire wire bead mechanical performance testing device provided in an embodiment of the present invention;

[0043] Figure 2 A detailed cross-sectional view of the upper loading and measurement module of a tire wire bead mechanical performance testing device provided in an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram illustrating the working principle of a tire wire bead mechanical performance testing device provided in an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of a mechanical model for evaluating the mechanical properties of a tire wire ring when the number of arc-shaped clamping devices is n, as provided in an embodiment of the present invention; the left image is the main view, and the right image is an enlarged view of B in the left image;

[0046] Figure 5 This is a schematic diagram of a mechanical model for evaluating the mechanical performance of a tire steel wire ring when the number of arc-shaped clamping devices is n=6, as provided in an embodiment of the present invention; the left figure is the main view, and the right figure is an enlarged view of C in the left figure;

[0047] Figure 6 A schematic diagram illustrating the nonlinear proportional relationship between the strain proportionality coefficient and the number of arc-shaped clamping devices in a method for evaluating the mechanical properties of tire steel wire rings provided in an embodiment of the present invention.

[0048] Figure 7 A schematic diagram of the circumferential stiffness curve of a tire wire bead mechanical performance testing device provided in this embodiment of the invention;

[0049] Figure 8 A schematic diagram of the radial stiffness curve of a tire wire ring collected by a mechanical performance testing device provided in an embodiment of the present invention.

[0050] Figure 9 A schematic diagram of the stress-strain relationship curve of a tire wire ring collected by a mechanical performance testing device provided in an embodiment of the present invention;

[0051] The attached diagram is labeled as follows: 1-device base 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 clamping device, 12-lower slide rail, 13-displacement measurement module, 14-bottom actuator force, 15-wire ring mechanical model, 16-arc clamping device mechanical model, 17-transmission device pressure mechanical model. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical methods of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

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

[0054] like Figure 1 , Figure 2 As shown, the tire wire bead mechanical performance testing device of the present invention includes:

[0055] Device base plate 1, used to place the entire device structure;

[0056] Bottom actuator 2, used to provide vertical lift;

[0057] Bottom support column 3 is used to support the upper loading and measurement system;

[0058] The middle plate 4 of the device is used to install the lower rail 12 of the instrument and to house the upper structure;

[0059] Upper support column 5 is used to support the top plate 6 of the device;

[0060] The top plate 6 of the device is used to install the upper slide rail 7 of the instrument;

[0061] The center loading device 8 is coaxially arranged with the bottom actuator and is driven upward by the lifting force.

[0062] Several transmission devices 9 are evenly distributed around the central loading device and slide outward synchronously when the central loading device moves upward;

[0063] Several arc-shaped clamping devices 11 are arranged one-to-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.

[0064] Force measurement module 10 is located between each transmission device and the corresponding arc-shaped clamping device, and is used to collect the thrust in real time.

[0065] The displacement measurement module 13 is arranged opposite the arc-shaped clamping device and is used to collect the radial displacement of the wire ring in real time.

[0066] The upper slide rail 7 and the lower slide rail 12 respectively constrain 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 lift of the bottom actuator is converted into 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 in the process.

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

[0068] The loading system consists of an upper slide rail 7, a central loading device 8, a transmission device 10, an arc-shaped clamping device 11, and a lower slide rail 12. The loading is driven by the bottom actuator, which pushes the central loading device upward, thereby driving the peripheral transmission device to push the arc-shaped clamping device to load the wire ring. This converts the lift force of the bottom actuator into a thrust force in the horizontal plane, and at the same time amplifies the lift force of the actuator.

[0069] The force measurement module, through the force measurement module 10 between the transmission device 10 and the arc-shaped clamping device 11, obtains the pushing force of the arc-shaped clamping device 11 on the steel wire ring. That is, the force measurement module collects the pressure of the transmission device on the arc-shaped clamping device in real time, thereby realizing the acquisition of the loading force value in the horizontal plane of the steel wire ring. Therefore, the total clamping force on the tire steel wire ring is obtained. The calculation formula is:

[0070] (1)

[0071] In the formula, The force values ​​(in kN) of each force measurement module are given, n is the number of arc-shaped clamping devices, and m is the index value.

[0072] Displacement measurement module 13 is installed directly opposite the arc-shaped clamping device 11. By loading the steel wire ring with n arc-shaped clamping devices 11, the radial deformation of the steel wire ring can be measured. This allows us to obtain the circumferential deformation of the entire wire coil. 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 cross-sectional radius 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 on the cross-section of the wire ring 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 on the cross-section of the wire ring 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] in:

[0086] (8)

[0087] In the formula, The strain proportionality coefficient, Let n be the equivalent strain when n arc-shaped clamping devices apply load to the wire ring. This represents the actual strain of the wire ring during the actual processing.

[0088] This invention treats the tire wire bead as a homogeneous material and evaluates and analyzes its mechanical properties to obtain quantitative evaluation results, including the equivalent elastic modulus of the homogeneous material. The formula is:

[0089] (9)

[0090] In the formula, The cross-sectional area of ​​the wire coil is as follows: , The total clamping force on the tire wire ring is obtained by equation (1).

[0091] This invention proposes a method for evaluating the stiffness of tire bead rings based on a displacement measurement module, a force measurement module, and a proposed mechanical model. This method facilitates subsequent finite element analysis of tires. The circumferential stiffness of the bead rings is obtained based on the relationship between the circumferential force and circumferential deformation of the bead rings. Evaluation methods:

[0092] (10)

[0093] in:

[0094] (11)

[0095] In the formula, To treat the steel wire coil as an equivalent elastic modulus of a homogeneous material, This represents the circumferential deformation of the wire loop (in mm). This is the average radius of the wire loop (in mm). This represents the cross-sectional area of ​​the wire coil.

[0096] Furthermore, a method for evaluating the radial stiffness of the wire ring can be derived based on the relationship between the pressure exerted on the wire ring by the arc-shaped clamping device and the radial deformation of the 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 a 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 one embodiment of the present invention, an actuator at the bottom of a tire wire bead mechanical performance testing device applies an upward thrust to an intermediate loading device, which drives a transmission device to push an arc-shaped clamping device to load the wire bead. Taking a configuration of 6 arc-shaped clamping devices as an example, the thrust of each arc-shaped clamping device on the wire bead and the radial displacement of the wire bead during the loading process are obtained through a force measurement module and a displacement measurement module. According to formula (9) (n=6):

[0119] ;

[0120] In one embodiment of the present invention, the tire wire bead mechanical performance testing device of the present invention takes 6 arc-shaped clamping devices as an example. Then, when n=6, substituting into formula (11) yields:

[0121] ;

[0122] The steel wire ring was subjected to a loading test using a mechanical performance testing instrument with six arc-shaped clamping devices that were actually manufactured. The circumferential stiffness curve of the tire steel wire ring was obtained as follows: Figure 7 As shown.

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

[0124] ;

[0125] The wire rings were subjected to loading tests using a mechanical property testing instrument with six arc-shaped clamping devices that were actually manufactured. The radial stiffness curves of the wire rings were obtained as follows: Figure 8 As shown.

[0126] In one embodiment of the present invention, the tire wire bead mechanical performance testing device proposed in this invention takes six arc-shaped clamping devices 11 as an example. Based on the relationship between the cross-sectional stress and the actual strain of the tire wire bead, the following can be obtained:

[0127] (14)

[0128] in:

[0129] ;

[0130] ;

[0131] The steel wire ring was subjected to a loading test using a mechanical performance testing instrument with six arc-shaped clamping devices manufactured in actual production. The cross-sectional stress and true strain of the tire steel wire ring were obtained, resulting in the stress-strain curve of the tire steel wire ring cross-section, as shown below. Figure 9As shown, this stress-strain curve can guide the selection of a reasonable interference fit in tire design, so that the steel wire ring in the tire can fully exert its mechanical properties during service, while ensuring its structural safety. Figure 9 In this context, σ represents the cross-sectional stress of the tire wire bead obtained through testing, and ε represents the true strain of the wire bead obtained through testing and nonlinear evaluation criteria.

[0132] In one possible embodiment of the present invention, the present invention provides a tire steel wire bead mechanical performance testing device and evaluation method, wherein the number of arc-shaped clamping devices is... When more than 6 arc-shaped clamping devices are used to load the tire wire ring, according to formula (1), the wire ring is subjected to a total clamping force at this time.

[0133] According to the calculation formula (6) for the cross-sectional strength of the wire ring, we can obtain ( ):

[0134] .

[0135] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating the mechanical properties of tire steel wire rings, characterized in that, The mechanical performance evaluation of tire steel wire rings includes: The base plate of the device is used to support the entire device structure. Bottom support pillars are used to support the upper loading and measurement system; The middle plate of the device is used to install the lower rail of the instrument and to house the upper structure. The upper support column is used to support the top plate of the device; 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 slide rail installed on the top plate of the device and the lower slide rail installed on the middle plate of the device respectively constrain 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 lift of the bottom actuator is converted into 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 in the process. The method includes the following steps: Step 1: Apply radial thrust to the tire wire ring using a tire wire ring mechanical performance testing device, 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. The nonlinear evaluation criteria are: （7） in: （8） In the formula, The strain proportionality coefficient, Let n be the equivalent strain when n arc-shaped clamping devices apply load to the wire ring. This represents the actual strain of the wire coil during the actual processing. 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.

2. The method for testing the mechanical properties of tire steel wire rings 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 form a complete circle, and apply a uniform radial load to the wire ring in a synchronous manner at n points.

3. A method for testing the mechanical properties of tire steel wire rings 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. The method for evaluating the mechanical properties of tire steel wire rings according to claim 1, 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.

5. The method for evaluating the mechanical properties of tire steel wire rings according to claim 1, 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.

6. The method for evaluating the mechanical properties of tire steel wire rings according to claim 1, 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.

7. The method for evaluating the mechanical properties of tire steel wire rings according to claim 6, 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.

8. The method for evaluating the mechanical properties of tire steel wire rings according to claim 7, 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.

9. The method for evaluating the mechanical properties of tire steel wire rings according to claim 8, 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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