Method for measuring tire characteristics

Abstract

This provides a tire characteristic measurement method that can quickly measure the axial force when a tire crosses an obstacle at various speeds. [Solution] The tire characteristics measurement method includes: step S1 of mounting a tire T on a tire rotation shaft 4 of a tire testing machine 1 equipped with a drum 2 having a running surface S on which a first projection 3 is provided; acquisition step S2 of rotating the drum 2 continuously for multiple rotations to run the tire T on the running surface S and acquiring time-series data of the force acting on the tire rotation shaft 4 when the tire T crosses over the first projection 3 in each of the multiple rotations, wherein the rotation speed of the drum 2 when the tire T crosses over the first projection 3 is different in each rotation; and calculation step S3 of calculating force tire running speed series data based on the force time-series data.

Description

Technical Field

[0001] The present invention relates to a method for measuring tire characteristics.

Background Art

[0002] Patent Document 1 below discloses a method for evaluating the vibration characteristics of a tire using a drum tester. This drum tester includes a shaft on which a tire is mounted and a drum having a running surface provided with a step. The method involves mounting the tire on the shaft of the drum tester and running it on the running surface, and measuring the time-series data Y(t) of the axial force acting on the shaft when the tire crosses the step during the running process.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The force (axial force) generated on the tire rotation axis when the tire crosses a protrusion tends to vary depending on the running speed of the tire. Also, since the speed at which the maximum value and / or the extreme value of the axial force is shown is related to the motion characteristics of the tire, it is important to measure the time-series data as described above at various speeds. As an example of this type of measurement, the rotational speed of the drum was kept constant so that the running speed of the tire was 10 km / h, the axial force was measured over a plurality of revolutions, and the waveform was averaged to obtain the time-series data of the axial force at a tire running speed of 10 km / h. And since such a process was performed for various speeds, for example, at intervals of several km / h, there was a problem that it took a lot of time to measure the axial force.

[0005] This invention was devised in view of the above-described circumstances, and its main objective is to provide a tire characteristic measurement method that can measure the axial force when a tire crosses a protrusion at various speeds in a short amount of time. [Means for solving the problem]

[0006] The present invention relates to a method for measuring tire characteristics, comprising: a step of mounting a tire on the tire rotation axis of a tire testing machine equipped with a drum having a running surface provided with a first projection; an acquisition step of running the tire on the running surface by rotating the drum continuously for multiple rotations, and acquiring time-series data of the force acting on the tire rotation axis when the tire crosses over the first projection in each of the multiple rotations, wherein the acquisition step is to make the rotation speed of the drum different for each rotation when the tire crosses over the first projection; and a calculation step of calculating tire running speed-series data of the force based on the time-series data of the force. [Effects of the Invention]

[0007] By adopting the above configuration, the tire characteristics measurement method of the present invention can measure the axial force when a tire crosses a protrusion at various speeds in a short amount of time. [Brief explanation of the drawing]

[0008] [Figure 1] This is a conceptual overall diagram of the tire testing machine used in the tire characteristics measurement method of this embodiment. [Figure 2] This is a conceptual block diagram showing an example of the configuration of the control unit. [Figure 3] This flowchart shows an example of the processing procedure for measuring tire characteristics. [Figure 4] A flowchart illustrating an example of the processing procedure for the acquisition step. [Figure 5] This graph shows an example of time-series data of the force acting on the tire's rotation axis. [Figure 6]This graph shows an example of tire speed-series data for the force acting on the tire's rotation axis. [Figure 7] This graph shows an example of a tire's resonant frequency. [Modes for carrying out the invention]

[0009] One embodiment of the present invention will be described below with reference to the drawings. The drawings contain exaggerations and representations that differ from the actual structural dimensional ratios in order to aid in understanding the present invention. Furthermore, where there are multiple embodiments, the same or common elements are denoted by the same reference numerals throughout the specification, and redundant descriptions are omitted. Moreover, the specific configurations shown in the embodiments and drawings are for the purpose of understanding the content of the present invention, and the present invention is not limited to the specific configurations shown in the illustrations.

[0010] [Drum testing machine] Figure 1 is a conceptual overall diagram of the tire testing machine 1 used in the tire characteristics measurement method of this embodiment. As shown in Figure 1, the tire testing machine 1 includes a drum 2. The tire testing machine 1 of this embodiment further includes a drum support section 11, a tire support section 12, an axial force detection section 13, a drum rotation position detection section 14, and a control section 15.

[0011] The drum 2 in this embodiment is, for example, cylindrical and equipped with a drum rotation shaft 18. The drum 2 is a so-called outside drum, having a running surface S on its cylindrical outer surface 2o for the tire T to run on. In other embodiments, the drum 2 may be a so-called inside drum (not shown), having a running surface S on its cylindrical inner surface.

[0012] The outer diameter of drum 2 is conventionally, for example, 1500 to 3500 mm. In this embodiment, the outer diameter of drum 2 is approximately 2500 mm.

[0013] On the running surface S of the drum 2, for example, one first protrusion 3 is provided. The first protrusion 3 locally protrudes in the drum diameter direction from the cylindrical outer peripheral surface 2o. The first protrusion 3 is, for example, substantially rectangular parallelepiped-shaped in a cross section orthogonal to the drum rotation axis 18. Although not particularly limited, the height of the first protrusion 3 is, for example, 2 to 30 mm. Also, the length of the first protrusion 3 in the drum circumferential direction is, for example, 2 to 200 mm. As an example, the first protrusion 3 has a height of 10 mm and lengths of 20 mm each for the bottom side and the top side in the drum circumferential direction.

[0014] The drum support portion 11 includes, for example, a support portion 16 and a drive portion 17.

[0015] The support portion 16 includes, for example, a pair of fixed frames provided on both axial sides of the drum 2 and bearings (not shown) fixed to each fixed frame. The bearings support the drum rotation axis 18 rotatably in a substantially horizontal state. Therefore, the drum 2 is rotatable about the axis of the drum rotation axis 18.

[0016] The drive portion 17 includes, for example, a rotary drive portion such as an electric motor M. The electric motor M is connected to the drum rotation axis 18 via a linking means 19 such as a belt. Therefore, by rotationally driving the electric motor M, the drum 2 can be rotated. Also, the drive portion 17 of the present embodiment is configured such that when the rotation of the electric motor M is stopped, the drum 2 can continue to rotate (coast) by inertia until the kinetic energy due to the inertial force at that time is consumed. Therefore, when the electric motor M is stopped, the drum 2 rotating at a certain rotational speed gradually decreases its rotational speed and finally stops. The electric motor M is driven and stopped by a signal from the control portion 15.

[0017] The tire support portion 12 of the present embodiment includes, for example, a support means 21 and a pressing means​​​The support means 21 can rotatably support a rim (not shown) of the tire T assembled with the rim and filled with internal pressure. The pressing means 20 is, for example, a fluid pressure cylinder having a telescopic rod, and can move the support means 21 up and down. By adjusting the amount of expansion and contraction of the rod of the pressing means 20, the relative distance between the tire T and the drum 2 can be adjusted. Therefore, the tire support portion 12 can bring the tire T into contact with the running surface S of the drum 2 with a predetermined ground contact pressure. Thereby, when the drum 2 rotates, the tire T can rotate and run due to the friction with the running surface S of the drum 2.

[0019] In a preferred embodiment, the tire support portion 12 may further include a suspension portion 22. The suspension portion 22 is provided, for example, between the pressing means 20 and the support means 21, and absorbs the vertical vibration of the tire T. The suspension portion 22 includes, for example, a spring portion 22A and a damper portion 22B. Therefore, the suspension portion 22 helps to reproduce the behavior of the tire during running closer to that of an actual vehicle.

[0020] The axial force detection unit 13 of the present embodiment detects the force acting on the tire rotation axis 4 when the tire T crosses the first protrusion 3 of the running surface S (hereinafter sometimes simply referred to as "axial force"). The axial force detection unit 13 of the present embodiment can detect, as the axial force, the axial force in the vertical direction A of the tire T and / or the axial force in the front-rear direction B of the tire T. The axial force detection unit 13 transmits, for example, a signal corresponding to the detected axial force to the control unit 15. The axial force detection unit 13 is attached to, for example, the tire rotation axis 4. A known sensor or the like can be appropriately employed for the axial force detection unit 13, and a load cell is employed in the present embodiment.

[0021] The drum rotation position detection unit 14 of the present embodiment is configured to output one pulse signal (trigger signal) every time the drum 2 makes one rotation. The trigger signal of the drum rotation position detection unit 14 is transmitted to the control unit 15. In other embodiments, the drum rotation position detection unit 14 may be configured to continuously detect the rotation position of the drum 2.

[0022] The drum rotation position detection unit 14 is, for example, attached to the drum rotation shaft 18. In this embodiment, the drum rotation position detection unit 14 is positioned to output a trigger signal just before the tire T crosses over the first projection 3 on the running surface S. Various types of photosensors and the like can be appropriately used in the drum rotation position detection unit 14.

[0023] Figure 2 is a conceptual block diagram showing an example of the configuration of the control unit 15. The control unit 15 in this embodiment includes an acquisition unit 23, a calculation unit 24, and a storage unit 25. The acquisition unit 23 and the calculation unit 24 mainly perform the acquisition step S2 and the calculation step S3, respectively, which will be described later. Such a control unit 15 can be configured by, for example, a computer. In this embodiment, the control unit 15 is provided in the tire testing machine 1, but in other embodiments, the control unit 15 may be configured separately from the tire testing machine 1.

[0024] In this embodiment, the acquisition unit 23 can output a drive signal for the electric motor M to the drive unit 17 in order to rotate the drum 2 while it is stopped. The acquisition unit 23 can also output a signal to the drive unit 17 to stop the drive signal for the electric motor M in order to stop the rotating drum 2. When the drive signal is stopped, the drum 2 will coast (rotate freely by inertia) and eventually come to a stop. In addition, in this embodiment, the acquisition unit 23 can also receive a signal corresponding to the axial force from the axial force detection unit 13 and a trigger signal from the drum rotation position detection unit 14. Furthermore, the acquisition unit 23 can acquire time-series data of the axial force from these received signals and store it in the storage unit 25.

[0025] In this embodiment, the calculation unit 24 can calculate tire travel speed series data of axial force based on the time series data of axial force stored in the storage unit 25 by the acquisition unit 23, and store it in the storage unit 25.

[0026] The control unit 15 of this embodiment further includes a first evaluation unit 28, a second evaluation unit 29, and a display unit 26. The first evaluation unit 28 and the second evaluation unit 29 each perform the evaluation of tire characteristics as described later. The display unit 26 of this embodiment can display various data processed by the acquisition unit 23, the calculation unit 24, the first evaluation unit 28, and the second evaluation unit 29 on the monitor 27.

[0027] [Method for measuring tire characteristics] Next, a method for measuring tire characteristics using the tire testing machine 1 of this embodiment will be described. Figure 3 is a flowchart showing an example of the processing procedure for measuring tire characteristics. As shown in Figure 3, in the tire characteristics measurement method of this embodiment, first, the tire T is mounted on the tire rotation shaft 4 of the tire testing machine 1 so as to contact the running surface S of the drum 2 (step S1).

[0028] In step S1 of this embodiment, it is preferable that the tire T is pre-assembled onto the regular rim and filled with the regular internal pressure. Furthermore, it is even more preferable that the tire T is mounted by the pressing means 20 so that the regular load is applied. This makes it possible to bring the tire T closer to the actual driving conditions.

[0029] The aforementioned "standard rim" refers to the rim defined for each tire within the standards system that includes the standard on which the tire is based. For example, it is the "standard rim" for JATMA, the "Design Rim" for TRA, and the "Measuring Rim" for ETRTO.

[0030] The aforementioned "standard internal pressure" is the air pressure specified for each tire by each standard within the standards system, including the standard on which the tire is based. For JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0031] The aforementioned "standard load" refers to the load specified for each tire within the standard system, including the standard on which the tire is based, in the case of pneumatic tires for which various standards are defined. For example, it is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "LOAD CAPACITY" for ETRTO. In the case of tires for which various standards are not defined, the "standard load" refers to the maximum load applicable when using the tire, in accordance with the standards mentioned above.

[0032] Next, in the tire characteristics measurement method of this embodiment, time-series data of the axial force is acquired when the drum 2 is rotated continuously for multiple rotations (acquisition step S2). In acquisition step S2 of this embodiment, data of the axial force of the tire T in the vertical direction A is acquired. Figure 4 is a flowchart showing an example of the processing procedure for acquisition step S2. As shown in Figure 4, in acquisition step S2 of this embodiment, first, the drum 2 is rotated at a certain rotational speed (step S21).

[0033] The rotation of the drum 2 is performed by the acquisition unit 23 outputting a drive signal for the electric motor M to the drive unit 17. At this time, the acquisition unit 23 controls the rotational speed of the drum 2. As a result, in step S21 of this embodiment, the tire T can be driven on the running surface S. The rotational speed is, for example, the rotational speed at which the speed of the tire T becomes the running speed at which axial force data is to be acquired, and is predetermined based on the diameter of the tire T and the size of the drum 2.

[0034] During the rotation of drum 2, the acquisition unit 23 receives a signal corresponding to the axial force from the axial force detection unit 13 and a trigger signal from the drum rotation position detection unit 14.

[0035] Next, in the acquisition step S2 of this embodiment, the drum 2 is allowed to coast (step S22). In this embodiment, the drum 2 is allowed to coast by the acquisition unit 23 outputting a signal to the drive unit 17, which stops the drive signal of the electric motor M. As a result, the rotational speed of the drum 2 gradually decreases from a certain rotational speed due to the resistance caused by contact with the tire T.

[0036] Next, in acquisition step S2 of this embodiment, time-series data of the axial force A in the vertical direction of the tire T is acquired (measured) (step S23). Such measurement is performed based on the signal corresponding to the axial force received by the acquisition unit 23. Figure 5 is a graph showing an example of time-series data of the axial force A in the vertical direction of the tire T. As shown in Figure 5, the time-series data of the axial force A in the vertical direction of the tire T is acquired as data of the relationship between the axial force A in the vertical direction of the tire T and time for each rotation of the drum 2.

[0037] Returning to Figure 4, in the acquisition step S2 of this embodiment, the tire travel speed is calculated (step S24). This calculation is performed based on the trigger signal received by the acquisition unit 23. In this embodiment, the tire travel speed is calculated for each rotation of the drum 2 as the circumference L of the drum 2 / the time required for one rotation of the drum 2. Here, the time required for one rotation of the drum 2 is the interval between the reception of trigger signals for each rotation of the drum 2 (the time from receiving one trigger signal to receiving the next trigger signal).

[0038] Next, in the acquisition step S2 of this embodiment, time-series data of the axial force A in the vertical direction of the tire T and the tire travel speed are stored together (step S25). In this embodiment, the acquisition unit 23 stores the time-series data of the axial force A in the vertical direction of the tire T acquired in step S23 and the tire travel speed calculated in step S24 together in the storage unit 25.

[0039] Next, in acquisition step S2 of this embodiment, it is determined whether the tire travel speed is less than or equal to a predetermined speed (step S26). Any tire travel speed can be set as the predetermined speed, but in this embodiment, it is set to 1 km / h. In this embodiment, if it is determined that the tire travel speed is less than or equal to the predetermined speed (Yes in step S26), acquisition step S2 is terminated. On the other hand, if it is determined that the tire travel speed is not less than or equal to the predetermined speed (No in step S26), steps S23 to S25 are executed again. As a result, time-series data of the axial force A in the vertical direction of the tire T when the tire T crosses over the first projection 3 is acquired (measured) for each of the multiple rotations of the drum 2, and the rotation speed of the drum 2 when the tire T crosses over the first projection 3 can be made different for each rotation.

[0040] Figure 5 illustrates the time-series data of the axial force A in the vertical direction of the tire T from the first to the fourth rotation of the drum 2. More specifically, Figure 5 shows the trigger signal and the time t1 to t4 required for one rotation of the drum 2 from the first to the fourth rotation. It also shows the average speed V1 to V4 of the tire T from the first to the fourth rotation of the drum 2. In this embodiment, the display unit 26 displays the graph illustrated in Figure 5 on the monitor 27. This makes it possible to visualize the time-series data of the axial force A in the vertical direction of the tire T.

[0041] In the acquisition step S2 of this embodiment, it is preferable to vary the rotational speed of the drum 2 by 1 km / h or more when the tire T crosses over the first projection 3. This makes it possible to acquire (measure) axial force data at various tire travel speeds while shortening the time required to measure the time-series data of the axial force.

[0042] Returning to Figure 3, in the tire characteristic measurement method of this embodiment, the tire running speed series data of the axial force A in the vertical direction of the tire T is calculated (calculation step S3). Such calculation is performed based on the set of time-series data of the axial force A in the vertical direction of the tire T and the tire running speed stored in the storage unit 25 by the acquisition unit 23 in step S25. Figure 6 is a graph showing an example of the tire running speed series data of the axial force A in the vertical direction of the tire T. As shown in Figure 6, in calculation step S3 of this embodiment, the calculation unit 24 calculates the tire running speed series data of the axial force A in the vertical direction of the tire T based on the difference between the maximum and minimum values ​​of the time-series data of the axial force A in the vertical direction of the tire T for each rotation of the drum 2. This makes it possible to measure the speed-dependent axial force in a short time. In this embodiment, the display unit 26 displays the graph shown in Figure 6 on the monitor 27. This makes it possible to visualize the running speed series data of the axial force A in the vertical direction of the tire T.

[0043] As described above, the tire characteristic measurement method of this embodiment can acquire time-series data of axial force by varying the tire T's running speed at the time the tire T crosses over the first protrusion 3 on each lap. Furthermore, the tire characteristic measurement method of this embodiment can calculate axial force series data of the tire running speed based on the time-series data of axial force acquired in this way. This makes it possible to measure the axial force when the tire T crosses over the first protrusion 3 at various tire running speeds in a short amount of time. Specifically, at various tire running speeds of 80 km / h or less, the tire characteristic measurement method of this embodiment can reduce the measurement time by approximately 83% compared to conventional measurement methods.

[0044] [Method for evaluating tire characteristics] As shown in Figure 3, in the tire characteristics measurement method described above, steps S1 to S3 were performed, but in the tire characteristics evaluation method, the tire characteristics may be further evaluated thereafter (step S4).

[0045] In this embodiment, step S4 preferably includes a first evaluation step in which the tire characteristics are evaluated based on the maximum value and / or local maximum value of the tire running speed series data of the axial force A in the vertical direction of the tire T, calculated by the tire characteristics measurement method. In this embodiment, the first evaluation unit 28 calculates the maximum value and local maximum value of the tire running speed series data of the axial force A in the vertical direction of the tire T, and the tire running speed at the time of the maximum value and local maximum value.

[0046] As shown in Figure 6, the tire speed series data for the axial force of tire T in the vertical direction A has a maximum value F of axial force. In this embodiment, the maximum value F is also the local maximum value. In other embodiments, the tire speed series data for the axial force of tire T in the vertical direction A may have the maximum value and local maximum value of axial force separately. In step S4 of this embodiment, in any embodiment, the tire characteristics can be evaluated based on the maximum value and local maximum value of the tire speed series data for the axial force of tire T in the vertical direction A, and the tire speed at which the maximum value and local maximum value occur, so that the characteristics of tire T can be evaluated without omission.

[0047] Step S4 of this embodiment may include a second evaluation step in which the time-series data of the axial force A in the vertical direction of the tire T, calculated by the tire characteristic measurement method, is frequency-analyzed, and the frequency at which the frequency-series data of the axial force A in the vertical direction of the tire T peaks is evaluated as the resonant frequency of the tire T. In this embodiment, the second evaluation unit 29 calculates the frequency-series data of the axial force by frequency-analyzing the time-series data of the axial force A in the vertical direction of the tire T. Furthermore, the second evaluation unit 29 calculates the frequency at which the frequency-series data of the axial force A in the vertical direction of the tire T peaks.

[0048] Figure 7 is a graph showing an example of the resonant frequency of tire T. As shown in Figure 7, in the frequency analysis of the time-series data of the axial force in the vertical direction A of tire T at the example tire speeds VA, VB, and VC, the axial force in the vertical direction A of tire T peaks at the resonant frequency f of tire T. As described above, tire speed VA is the tire speed at which the axial force in the vertical direction A of tire T is at its maximum value F. At such a tire speed VA, the peak of the axial force in the vertical direction A of tire T is particularly large, and the resonance of tire T is excited particularly strongly. Therefore, by performing a frequency analysis of the time-series data of the axial force in the vertical direction A of tire T at tire speed VA, the resonant frequency f of tire T can be calculated with high accuracy. In this embodiment, the display unit 26 displays the graph shown in Figure 7 on the monitor 27. This makes it possible to visualize the resonant frequency f of tire T.

[0049] In this embodiment, the frequency analysis range is preferably 0.7 to 150 Hz. This allows for efficient frequency analysis and reduces the time required to calculate the resonant frequency f of the tire T.

[0050] Although particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments and can be implemented in various modified forms.

[0051] [Note] The present invention includes the following embodiments.

[0052] [Invention 1] A method for measuring tire characteristics, A step of mounting a tire onto the tire rotation shaft of a tire testing machine equipped with a drum having a running surface on which a first projection is provided, An acquisition step comprising: rotating the drum continuously for multiple rotations to cause the tire to travel on the running surface, and acquiring time-series data of the force acting on the tire's rotation axis when the tire crosses the first protrusion in each of the multiple rotations, wherein the rotation speed of the drum when the tire crosses the first protrusion differs in each rotation; The calculation step includes calculating tire speed series data of the force based on the time series data of the force, Methods for measuring tire characteristics. [Invention 2] The tire characteristics measurement method according to the present invention 1, wherein the acquisition step involves gradually decreasing the rotational speed of the drum from a certain rotational speed. [Invention 3] The tire characteristics measurement method according to the present invention 1, wherein the acquisition step involves gradually reducing the rotational speed of the drum by allowing the drum to coast from a certain rotational speed. [4th Invention] The tire characteristics measurement method according to any one of invention 1 to 3, wherein the acquisition step involves making the rotational speed of the drum when the tire crosses the first protrusion differ by 1 km / h or more in each circumference. [5th ​​Invention] The tire characteristics measurement method according to any one of invention 1 to 4, wherein the calculation step involves calculating tire speed series data of the force based on the difference between the maximum and minimum values ​​of the time series data of the force. [Invention 6] A method for evaluating tire characteristics, A method for evaluating tire characteristics, comprising a first evaluation step of evaluating the tire characteristics based on the maximum value and / or local maximum of the tire running speed series data of the force calculated by the measurement method described in any one of inventions 1 to 5. [7th Invention] A method for evaluating tire characteristics, A method for evaluating tire characteristics, comprising a second evaluation step of performing frequency analysis on the time-series data of force obtained by the measurement method described in any one of inventions 1 to 5, and evaluating the frequency at which the frequency-series data of force peaks as the resonant frequency of the tire. [8th Invention] The tire characteristics evaluation method according to the present invention, wherein the range of the frequency analysis is 0.7 to 150 Hz. [Explanation of symbols]

[0053] 1. Tire testing machine 2 drums 3 1st protrusion 4 Tire rotation axis T-tire S Running surface S2 Acquisition Steps S3 Calculation Step

Claims

1. A method for measuring tire characteristics, A step of mounting a tire onto the tire rotation shaft of a tire testing machine equipped with a drum having a running surface on which a first projection is provided, An acquisition step in which the drum is rotated continuously for multiple rotations to make the tire run on the running surface, and time-series data of the force acting on the tire rotation axis when the tire crosses over the first protrusion in each of the multiple rotations, wherein the rotation speed of the drum when the tire crosses over the first protrusion is different in each rotation, The calculation step includes calculating tire speed series data of the force based on the time series data of the force, Methods for measuring tire characteristics.

2. The tire characteristics measurement method according to claim 1, wherein in the acquisition step, the rotational speed of the drum is gradually reduced from a certain rotational speed.

3. The method for measuring tire characteristics according to claim 1, wherein in the acquisition step, the rotational speed of the drum is gradually reduced by coasting the drum from a certain rotational speed.

4. The tire characteristics measurement method according to claim 2, wherein in the acquisition step, the rotational speed of the drum when the tire crosses the first protrusion is made to differ by 1 km / h or more in each rotation.

5. The tire characteristic measurement method according to any one of claims 1 to 4, wherein the calculation step involves calculating tire speed series data of the force based on the difference between the maximum and minimum values ​​of the time series data of the force.

6. A method for evaluating tire characteristics, A method for evaluating tire characteristics, comprising a first evaluation step of evaluating the tire characteristics based on the maximum value and / or local maximum value of the tire running speed series data of the force calculated by the measurement method described in claim 1.

7. A method for evaluating tire characteristics, A method for evaluating tire characteristics, comprising a second evaluation step of performing frequency analysis on the time-series data of force obtained by the measurement method described in claim 1, and evaluating the frequency at which the frequency-series data of force peaks as the resonant frequency of the tire.

8. The method for evaluating tire characteristics according to claim 7, wherein the range of the frequency analysis is 0.7 to 150 Hz.

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