A Static Tire Radial Force Zoning Fitting Method and Device

Abstract

The present invention discloses a method and device for fitting static tire radial force partitioning. The method includes: conducting a static radial rigidity test on a test tire to obtain multiple sets of vertical forces and radial displacements during the load loading stage and the load unloading stage, plotting a scatter diagram of test data of vertical force and radial displacement with the radial displacement as the abscissa and the vertical force as the ordinate; dividing the load loading stage and the load unloading stage of the test data scatter diagram according to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load respectively to form six partitions; separately performing a cubic polynomial fitting on the vertical force and radial displacement of each partition to determine the radial rigidity of each partition; and fitting a radial rigidity curve based on the radial rigidity of each partition, thereby further improving the accuracy of the static tire radial rigidity result and making it more convenient for tire characteristic analysis.

Description

Technical Field

[0001] The present application relates to the field of tire mechanical property data processing, and more specifically, to a method and device for fitting static tire radial force in zones. Background Art

[0002] When a tire bears a load and is subjected to a radial force, the relationship between the radial force and the displacement is called the radial stiffness, which affects the comfort performance of the tire.

[0003] In the prior art, when performing a static radial stiffness test on a tire, only the test data in the vertical force loading stage is obtained, and the test data in the vertical force unloading stage is not considered. The accuracy of the static tire radial stiffness obtained is low, and the obtained radial stiffness values are all single-point values, which is not convenient for analyzing the characteristics of the tire.

[0004] Therefore, how to improve the accuracy of the static tire radial stiffness result and make it more convenient for tire characteristic analysis is a technical problem to be solved at present. Summary of the Invention

[0005] The present invention discloses a method for fitting static tire radial force in zones to solve the technical problems in the prior art that the accuracy of the static tire radial stiffness result is low and it is not convenient for tire characteristic analysis. The method includes:

[0006] Assemble the test tire onto the test rim, inflate the test tire to a preset air pressure and park it for a first preset duration, and fix the combination of the test tire and the test rim to the test rigid machine;

[0007] Apply a vertical force to the test tire at a preset moving speed until each preset target load is reached and finally the preset maximum target load is reached. Among them, after each preset target load or the preset maximum target load is reached and maintained for a second preset duration, the radial displacement is determined;

[0008] Unload the vertical force on the test tire from the preset maximum target load until it is reduced to each of the preset target loads respectively. Among them, after each reduction to a preset target load and maintaining the second preset duration, the radial displacement is determined;

[0009] Taking the radial displacement as the abscissa and the vertical force as the ordinate, draw a scatter plot of the test data of the vertical force and the radial displacement;

[0010] According to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load, divide the load loading stage and the load unloading stage of the test data scatter plot and form six zones;

[0011] Individually perform a separate cubic polynomial fitting on the vertical force and radial displacement of each partition and determine the radial rigidity of each partition;

[0012] Generate a radial rigidity curve by fitting the radial rigidities of each partition.

[0013] In some embodiments of the present application, individually perform a separate cubic polynomial fitting on the vertical force and radial displacement of each partition and determine the radial rigidity of each partition. Specifically:

[0014] Let the cubic polynomial fitting formula be y = ax 3 + bx 2 + cx + d. Individually fit the vertical force and radial displacement of each partition according to the cubic polynomial fitting formula to obtain the values of the constants a, b, and c;

[0015] Take the derivative of the cubic polynomial fitting formula to obtain the derivative formula y' = 3ax 2 + 2bx + c. Substitute the values of the constants a, b, and c into the derivative formula to determine the radial rigidity of each partition;

[0016] where y is the vertical force, x is the radial displacement, and y' is the radial rigidity.

[0017] In some embodiments of the present application, the preset maximum target load includes 80%, or 100%, or 120% of the maximum load of the test tire.

[0018] In some embodiments of the present application, before loading the vertical force on the test tire at the preset moving speed until each preset target load is reached, the method further includes:

[0019] Load the vertical force on the test tire at the preset moving speed until the pre-test load is reached, unload after maintaining for a third preset duration, repeat the preset number of times for pre-testing, and after the pre-testing is completed, inflate the test tire to the preset air pressure.

[0020] Correspondingly, the present invention also proposes a static tire radial force partition fitting device, and the device includes:

[0021] A loading module for loading a vertical force on the test tire;

[0022] A positioning module for determining the radial displacement of the test tire;

[0023] A controller for:

[0024] When receiving a test instruction sent by a user, the control loading module applies a vertical force to the test tire at a preset moving speed until each preset target load is reached and finally the preset maximum target load is reached. Among them, after each preset target load or the preset maximum target load is reached and maintained for a second preset duration, the radial displacement is determined by the positioning module;

[0025] The control loading module unloads the vertical force on the test tire from the preset maximum target load until it is reduced to each of the preset target loads respectively. Among them, after each reduction to a preset target load and maintaining the second preset duration, the radial displacement is determined by the positioning module;

[0026] Taking the radial displacement as the abscissa and the vertical force as the ordinate, draw a scatter diagram of the test data of the vertical force and the radial displacement;

[0027] According to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load, divide the load loading stage and the load unloading stage of the test data scatter diagram respectively and form six partitions;

[0028] Separate cubic polynomial fittings are performed on the vertical force and the radial displacement of each partition respectively, and the radial rigidity of each partition is determined;

[0029] Generate a radial rigidity curve according to the radial rigidity fittings of each partition.

[0030] In some embodiments of the present application, the controller is specifically used for:

[0031] Let the cubic polynomial fitting formula be y = ax 3 + bx 2 + cx + d, perform separate fittings on the vertical force and the radial displacement of each partition according to the cubic polynomial fitting formula, and obtain the numerical values of the constants a, b, and c;

[0032] Derive the cubic polynomial fitting formula to obtain the derivative formula y' = 3ax 2 + 2bx + c, substitute the numerical values of the constants a, b, and c into the derivative formula to determine the radial rigidity of each partition;

[0033] Among them, y is the vertical force, x is the radial displacement, and y' is the radial rigidity.

[0034] In some embodiments of the present application, the preset maximum target load includes 80%, or 100%, or 120% of the maximum load of the test tire.

[0035] In some embodiments of the present application, the controller is further used for:

[0036] When receiving a preliminary test instruction sent by a user, control the loading module to load a vertical force on the test tire at the preset moving speed until the preliminary test load is reached, unload after maintaining for a third preset duration, and repeat the preset number of times for the preliminary test.

[0037] By applying the above technical solution, a static radial rigidity test is carried out on the test tire to obtain multiple groups of vertical forces and radial displacements in the load loading stage and the load unloading stage. Taking the radial displacement as the abscissa and the vertical force as the ordinate, a scatter plot of the test data of the vertical force and the radial displacement is drawn; according to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load, the load loading stage and the load unloading stage of the test data scatter plot are divided respectively to form six partitions; the vertical forces and radial displacements of each partition are separately fitted with a cubic polynomial to determine the radial rigidity of each partition; a radial rigidity curve is generated by fitting the radial rigidities of each partition, thereby further improving the accuracy of the static tire radial rigidity result and making it more convenient for tire characteristic analysis. Brief Description of the Drawings

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0039] Figure 1 Fig. shows a schematic flow chart of a method for fitting static tire radial force partitions proposed in an embodiment of the present invention;

[0040] Figure 2 Fig. shows a schematic diagram of a tire coordinate system in an embodiment of the present invention;

[0041] Figure 3 Fig. shows a schematic diagram of a static tire radial rigidity test in an embodiment of the present invention;

[0042] Figure 4 Fig. shows a schematic structural diagram of a device for fitting static tire radial force partitions proposed in an embodiment of the present invention. Detailed Description of the Embodiments

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0044] The embodiment of the present application provides a method for fitting the radial force of a static tire in zones. By performing a cubic polynomial fit on the test data of the radial force in each zone, the test data in the load application stage and the load unloading stage can be accurately fitted into a smooth curve, which is used to calculate tire characteristic values, conduct benchmark analysis, or be used for tire model identification, featuring high accuracy, good repeatability, and high efficiency.

[0045] As Figure 1 shown, the method includes the following steps:

[0046] Step S101: Assemble the test tire onto the test rim, inflate the test tire to a preset air pressure and park it for a first preset duration, and then fix the combination of the test tire and the test rim to the test rigid machine.

[0047] In this embodiment, first, a tire radial rigidity test is performed, and the final static radial rigidity result is determined according to the test data. The test rigid machine is used to perform a radial rigidity test on the test tire.

[0048] First, select a tire with good appearance quality as the test tire, then assemble the test tire onto the test rim, inflate the test tire to a preset air pressure and park it for a first preset duration.

[0049] In some embodiments of the present application, the preset air pressure can be 250 kPa or 290 kPa, and the first preset duration is not less than 24 h. Those skilled in the art can flexibly set different preset air pressures and first preset durations according to actual needs.

[0050] Step S102: Load a vertical force on the test tire at a preset moving speed until each preset target load is reached and finally the preset maximum target load is reached. Among them, after each preset target load or the preset maximum target load is reached and maintained for a second preset duration, the radial displacement is determined.

[0051] In this embodiment, the direction of the vertical force corresponds to the tire coordinate system. As Figure 2 shown, it is a schematic diagram of the tire coordinate system. The vertical force corresponds to the Z'-axis of the tire coordinate system. The tire coordinate system is a right-handed rectangular coordinate system with the tire contact center as the origin. The X'-axis is the intersection line of the tire center plane and the road plane, and the forward direction of the tire center plane is positive; the Z'-axis is the vertical line, and the upward direction is positive; the Y'-axis is in the road plane, and the direction is determined according to the right-hand rule.

[0052] Pre-set multiple preset target loads, such as Figure 3As shown, a vertical force Fz is applied to the test tire at a preset moving speed until each preset target load is reached and finally the preset maximum target load is reached. After each preset target load or preset maximum target load is reached, to improve the test accuracy, a second preset duration is maintained, and then the radial displacement Sz is determined, so that multiple sets of vertical forces Fz and radial displacements Sz corresponding to each preset target load and the preset maximum target load can be obtained during the load application stage.

[0053] Optionally, the preset moving speed is 50 mm / min and the second preset duration is 1 min. Those skilled in the art can flexibly set different preset moving speeds and second preset durations according to actual needs.

[0054] To improve the accuracy of test data, in some embodiments of the present application, before applying a vertical force to the test tire at a preset moving speed until each preset target load is reached, the method further includes:

[0055] Apply a vertical force to the test tire at the preset moving speed until a preliminary test load is reached, unload after maintaining a third preset duration, repeat the preset number of times for the preliminary test, and inflate the test tire to the preset air pressure after the preliminary test is completed.

[0056] In this embodiment, before officially performing the radial rigidity test on the test tire, a preset number of preliminary tests are first carried out. After determining that there is no problem with the test tire and the test rigidity machine, the test tire is inflated to the preset air pressure for the official test.

[0057] Optionally, the preliminary test load is 80% of the maximum load of the test tire, and the third preset duration can be 5 s.

[0058] Step S103, unload the vertical force from the test tire from the preset maximum target load until it is reduced to each of the preset target loads respectively, wherein the radial displacement is determined after each reduction to a preset target load and maintaining the second preset duration.

[0059] In this embodiment, as Figure 3 shown, after the test in the load application stage is completed, the load unloading stage is entered. The vertical force Fz is unloaded from the test tire from the preset maximum target load until it is reduced to each of the preset target loads respectively. After each reduction to a preset target load, the second preset duration is maintained, and then the radial displacement Sz is determined, so that multiple sets of vertical forces Fz and radial displacements Sz corresponding to each preset target load can be obtained during the load unloading stage.

[0060] Step S, draw a scatter plot of the test data of the vertical force and the radial displacement with the radial displacement as the abscissa and the vertical force as the ordinate.

[0061] In this embodiment, based on multiple sets of vertical forces and radial displacements obtained in steps S102 and S103, a scatter plot of test data of vertical force and radial displacement is plotted with the radial displacement as the abscissa and the vertical force as the ordinate.

[0062] Step S105: Divide the load loading stage and the load unloading stage of the test data scatter plot according to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load respectively to form six partitions.

[0063] It can be understood that the load loading stage of the test data scatter plot is divided into three partitions corresponding to 0%-30%, 30%-60%, and 60%-100% of the set maximum target load, and the load unloading stage of the test data scatter plot is divided into three partitions corresponding to 0%-30%, 30%-60%, and 60%-100% of the set maximum target load.

[0064] Step S106: Separately perform a cubic polynomial fitting on the vertical force and radial displacement of each partition and determine the radial rigidity of each partition.

[0065] In some embodiments of the present application, in order to accurately determine the radial rigidity of each partition, a cubic polynomial fitting is separately performed on the vertical force and radial displacement of each partition to determine the radial rigidity of each partition. Specifically:

[0066] Let the cubic polynomial fitting formula be y = ax 3 + bx 2 + cx + d, and perform a separate fitting on the vertical force and radial displacement of each partition according to the cubic polynomial fitting formula to obtain the values of constants a, b, and c;

[0067] Derive the cubic polynomial fitting formula to obtain the derivative formula y' = 3ax 2 + 2bx + c, and substitute the values of constants a, b, and c into the derivative formula to determine the radial rigidity of each partition;

[0068] Among them, y is the vertical force, x is the radial displacement, and y' is the radial rigidity.

[0069] It can be understood that y and Figure 3 Fz in Figure 3 are both vertical forces, and x and

[0070] Sz in

[0071] are both radial displacements.

[0070] It should be noted that the solutions of the above embodiments are only a specific implementation solution proposed in the present application, and other methods of separately performing a cubic polynomial fitting on the vertical force and radial displacement of each partition and determining the radial rigidity of each partition belong to the protection scope of the present application.

[0071] Step S107: Generate a radial stiffness curve by fitting the radial stiffness of each partition.

[0072] In this embodiment, a smooth radial stiffness curve is generated by fitting the radial stiffness of each partition. This radial stiffness curve can be used to calculate tire characteristic values, conduct benchmark analysis, or be used for tire model identification.

[0073] Optionally, in some embodiments of the present application, the preset maximum target load includes 80%, or 100%, or 120% of the maximum load of the test tire.

[0074] By applying the above technical solutions, a static radial stiffness test is performed on the test tire to obtain multiple sets of vertical forces and radial displacements in the load loading stage and the load unloading stage. Taking the radial displacement as the abscissa and the vertical force as the ordinate, a scatter plot of the test data of the vertical force and the radial displacement is plotted; the load loading stage and the load unloading stage of the test data scatter plot are divided according to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load respectively to form six partitions; the vertical forces and radial displacements of each partition are individually fitted with a cubic polynomial to determine the radial stiffness of each partition; a radial stiffness curve is generated by fitting the radial stiffness of each partition, thereby further improving the accuracy of the static tire radial stiffness result and making it more convenient for tire characteristic analysis.

[0075] The embodiment of the present application also proposes a static tire radial force partition fitting device, as Figure 4 shown, the device includes:

[0076] A loading module 10 for loading a vertical force on the test tire;

[0077] A positioning module 20 for determining the radial displacement of the test tire;

[0078] A controller 30 for:

[0079] When receiving a test instruction sent by the user, controlling the loading module 10 to load a vertical force on the test tire at a preset moving speed until each preset target load is reached and finally the preset maximum target load is reached. Among them, after each preset target load or the preset maximum target load is reached and maintained for a second preset duration, the radial displacement is determined by the positioning module 20;

[0080] Controlling the loading module 10 to unload the vertical force on the test tire from the preset maximum target load until it is reduced to each preset target load respectively. Among them, after each reduction to a preset target load and maintaining the second preset duration, the radial displacement is determined by the positioning module 20;

[0081] Taking the radial displacement as the abscissa and the vertical force as the ordinate, plot the scatter diagram of the test data of the vertical force and the radial displacement;

[0082] According to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load, divide the load loading stage and the load unloading stage of the test data scatter diagram respectively and form six partitions;

[0083] Separate cubic polynomial fitting is performed on the vertical force and the radial displacement of each partition respectively, and the radial rigidity of each partition is determined;

[0084] Generate a radial rigidity curve according to the fitting of the radial rigidity of each partition.

[0085] In the specific application scenario of the present application, the controller 30 is specifically used for:

[0086] Let the cubic polynomial fitting formula be y = ax 3 + bx 2 + cx + d, perform separate fitting on the vertical force and the radial displacement of each partition according to the cubic polynomial fitting formula, and obtain the numerical values of the constants a, b, and c;

[0087] Derive the cubic polynomial fitting formula to obtain the derivative formula y' = 3ax 2 + 2bx + c, substitute the numerical values of the constants a, b, and c into the derivative formula to determine the radial rigidity of each partition;

[0088] Among them, y is the vertical force, x is the radial displacement, and y' is the radial rigidity.

[0089] In the specific application scenario of the present application, the preset maximum target load includes 80%, or 100%, or 120% of the maximum load of the test tire.

[0090] In the specific application scenario of the present application, the controller 30 is further used for:

[0091] When receiving the pre-test instruction sent by the user, control the loading module 10 to load the vertical force on the test tire at the preset moving speed until the pre-test load is reached, unload after maintaining the third preset duration, and repeat the preset number of times for pre-test.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A static tire radial force partition fitting method, characterized in that, The method includes: Assembling the test tire onto the test rim, inflating the test tire to a preset air pressure and parking it for a first preset duration, and fixing the combination of the test tire and the test rim to the test rigid machine; Loading a vertical force on the test tire at a preset moving speed until each preset target load is reached and finally reaching the preset maximum target load, wherein the radial displacement is determined after each preset target load or the preset maximum target load is reached and maintained for a second preset duration; Unloading the vertical force on the test tire from the preset maximum target load until it is reduced to each of the preset target loads respectively, wherein the radial displacement is determined after each reduction to a preset target load and maintained for the second preset duration; Drawing a scatter plot of the test data of the vertical force and the radial displacement with the radial displacement as the abscissa and the vertical force as the ordinate; Dividing the load loading stage and the load unloading stage of the test data scatter plot according to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load respectively to form six zones; Separately performing a cubic polynomial fitting on the vertical force and the radial displacement of each zone and determining the radial rigidity of each zone; Generating a radial rigidity curve by fitting the radial rigidities of each zone.

2. The method according to claim 1, wherein Separately performing a cubic polynomial fitting on the vertical force and the radial displacement of each zone and determining the radial rigidity of each zone, specifically: Let the cubic polynomial fitting formula be y = ax 3 + bx 2 + cx + d. According to the cubic polynomial fitting formula, the vertical force and radial displacement of each partition are separately fitted to obtain the values of the constants a, b, and c; Derive the cubic polynomial fitting formula to obtain the derivative formula y' = 3ax 2 + 2bx + c, and substitute the values of the constants a, b, and c into the derivative formula to determine the radial rigidity of each partition; where y is the vertical force, x is the radial displacement, and y' is the radial rigidity.

3. The method according to claim 1, characterized in that The preset maximum target load includes 80%, or 100%, or 120% of the maximum load of the test tire.

4. The method according to claim 1, wherein Before loading the vertical force on the test tire at a preset moving speed until each preset target load is reached, the method further includes: Loading the vertical force on the test tire at the preset moving speed until a pretest load is reached, unloading it after maintaining a third preset duration, repeating the pretest for a preset number of times, and inflating the test tire to the preset air pressure after the pretest is completed.

5. A static tire radial force partition fitting device, characterized in that The device includes: A loading module for loading a vertical force on the test tire; A positioning module for determining the radial displacement of the test tire; A controller for: When receiving a test instruction sent by the user, controlling the loading module to load a vertical force on the test tire at a preset moving speed until each preset target load is reached and finally reaching the preset maximum target load, wherein the radial displacement is determined by the positioning module after each preset target load or the preset maximum target load is reached and maintained for a second preset duration; Controlling the loading module to unload the vertical force on the test tire from the preset maximum target load until it is reduced to each of the preset target loads respectively, wherein the radial displacement is determined by the positioning module after each reduction to a preset target load and maintained for the second preset duration; Drawing a scatter plot of the test data of the vertical force and the radial displacement with the radial displacement as the abscissa and the vertical force as the ordinate; Dividing the load loading stage and the load unloading stage of the test data scatter plot according to 0%-30%, 30%-60%, and 60%-100% of the preset maximum target load respectively to form six zones; Separate cubic polynomial fittings are performed on the vertical force and radial displacement of each partition respectively, and the radial rigidity of each partition is determined. A radial rigidity curve is generated by fitting the radial rigidities of each partition.

6. The device according to claim 5, characterized in that, The controller is specifically configured to: Let the cubic polynomial fitting formula be y = ax 3 + bx 2 + cx + d. According to the cubic polynomial fitting formula, the vertical force and radial displacement of each partition are separately fitted to obtain the values of the constants a, b, and c; Derive the cubic polynomial fitting formula to obtain the derivative formula y' = 3ax 2 + 2bx + c, and substitute the values of the constants a, b, and c into the derivative formula to determine the radial rigidity of each partition; Where y is the vertical force, x is the radial displacement, and y' is the radial rigidity.

7. The device according to claim 5, characterized in that, The preset maximum target load includes 80%, or 100%, or 120% of the maximum load of the test tire.

8. The device according to claim 5, characterized in that, The controller is further configured to: When receiving a pre-test instruction sent by the user, control the loading module to load a vertical force on the test tire at the preset moving speed until the pre-test load is reached, unload after maintaining for a third preset duration, and repeat the preset number of times for pre-testing.

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