Display method for grounding behavior of tire

Abstract

To provide a display method for grounding behavior of a tire that can evaluate local behavior of a tire grounding surface.SOLUTION: A display method for grounding behavior of a tire that displays force and a slip at a plurality of measurement points on a tire grounding surface of a tire tread includes: detecting force operating on the tire tread at respective measurement points when the tire is rolled; acquiring an image of the tire grounding surface simultaneously with the detection of the force; calculating a slip at the respective measurement points based upon the image of the tire grounding surface; and displaying a vector indicating the force at each measurement point and a vector indicating a slip at each measurement point over the image of the tire grounding surface.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a method for indicating the ground contact behavior of a tire. [Background technology]

[0002] Patent Document 1 describes a method for evaluating tire performance based on changes over time in the tire's slip ratio and friction coefficient. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-148456 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, it is not possible to evaluate local behavior on the tire contact patch.

[0005] An object of the present disclosure is to provide a method for displaying tire contact behavior that enables evaluation of local behavior in the tire contact patch. [Means for solving the problem]

[0006] One aspect of the present disclosure is 1. A method for displaying tire contact behavior, comprising displaying forces and slip at a plurality of measurement points on a tire contact surface of a tire tread, the method comprising: Obtaining measurement data of forces acting on the tire tread at each measurement point when the tire is rolling; Acquiring an image of the tire contact surface simultaneously with acquiring the force measurement data; Calculating slip at each measurement point based on the image of the tire contact surface; A vector indicating the force at each measurement point and a vector indicating the slip at each measurement point are superimposed on the image of the tire contact surface and displayed. The present invention provides a method for indicating the ground contact behavior of a tire, the method including:

[0007] This method visually displays the magnitude and direction of force and slip at multiple measurement points on the tire contact patch, allowing for evaluation of local force and slip on the tire contact patch. For example, visually displaying the magnitude and direction of force and slip at multiple measurement points on the tire contact patch while the tire is rolling allows for evaluation of the uneven wear performance of the tire. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a method for displaying tire contact behavior that enables evaluation of local behavior in the tire contact patch. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a display system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram of the measurement device shown in FIG. [Diagram 3] FIG. 3 is a flowchart for explaining a method for displaying the tire ground contact behavior executed by the display system shown in FIG. [Figure 4] FIG. 4 is an example of a display image obtained as a result of the display system shown in FIG. 1 executing the display method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0011] [Display System] FIG. 1 is a schematic configuration diagram of a display system 1 according to the present disclosure.

[0012] 1, the display system 1 according to the present embodiment includes a measurement device 10, a control device 20, and a display device 30. The display system 1 according to the present embodiment is configured to display an image showing local behavior of the tire contact surface of the tire tread when the tire is rolling. Specifically, the display system 1 according to the present embodiment is configured to visually display the force, slip, and wear energy at multiple measurement points on the tire contact surface of the tire tread when the tire is rolling, superimposed on the image of the tire contact surface.

[0013] The measuring device 10 is a test device for measuring the force acting on the tire tread at a predetermined measurement point on the tire contact surface of the tire, and for calculating the slip at the predetermined measurement point on the tire contact surface.

[0014] Fig. 2 is a schematic diagram of the measuring device 10. Referring to Fig. 2, the measuring device 10 includes a road plate 11 and a tire behavior detection unit 12 embedded in the road plate 11. The measuring device 10 detects a force at a predetermined measurement point on the tire contact surface by rolling the test tire T on the road plate 11, and calculates a slip at the predetermined measurement point. Here, when the test tire T is rolled on the road plate, the phase of the test tire T is adjusted so that the predetermined measurement point on the tire contact surface steps on the tire behavior detection unit 12.

[0015] Referring to FIG. 1, the tire behavior detection unit 12 includes a force detection unit 12a and a contact patch imaging unit 12b.

[0016] The force detection unit 12a measures the vector of a force acting on the tire tread at a predetermined measurement point on the tire contact surface when a test tire T (shown in FIG. 2) is rolled on the road plate 11 (shown in FIG. 2). The force detection unit 12a is, for example, a two-axis load cell capable of measuring two orthogonal components of force in a plane parallel to the surface of the road plate 11.

[0017] The contact patch imaging unit 12b images the tire contact patch including predetermined measurement points when a test tire T (shown in FIG. 2) is rolled on a road plate 11 (shown in FIG. 2).

[0018] The measurement device 10 includes a slippage calculation unit 13. The slippage calculation unit 13 calculates the slippage of the tire contact surface relative to the road surface plate 11 (shown in FIG. 2) at a predetermined measurement point on the tire contact surface by performing pattern matching based on the image of the tire contact surface captured by the contact surface imaging unit 12b.

[0019] The measuring device 10 of this embodiment measures the force and slip at one measurement point on the tire contact patch in one measurement test. The measuring device 10 also measures the slip and force at multiple points in time from when a predetermined measurement point on the tire contact patch comes into contact with a road plate 11 (shown in FIG. 2) until it leaves the road plate 11.

[0020] As the measuring device 10 of this embodiment, for example, a tire tread contact patch behavior measuring device described in Japanese Patent No. 6386304 can be used. Therefore, a detailed description of the measuring device 10 will be omitted in this specification.

[0021] The control device 20 includes a processor 21 that performs calculations, a storage unit 22, and a transmission / reception unit 23. The control device 20 of this embodiment cooperates with the measurement device 10 and the display device 30 to execute a display method for displaying an image representing local behavior of the tire tread at the tire contact surface when the tire is rolled. Specifically, the control device 20 of this embodiment cooperates with the measurement device 10 and the display device 30 to generate an image representing local behavior of the tire tread at the tire contact surface when the tire is rolled.

[0022] The processor 21 includes a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like.

[0023] The storage unit 22 stores a program or data required to execute the display method according to the present embodiment. The storage unit 22 is configured, for example, with an internal recording medium or an external recording medium. The internal recording medium includes a non-volatile memory, etc. The external recording medium includes a hard disk drive (HDD), a solid state drive (SSD), an optical disk device, etc.

[0024] The transmitting / receiving unit 23 transmits and receives data to and from the measuring device 10 and the display device 30. The transmitting / receiving unit 23 is configured with a communication circuit or a communication module for transmitting and receiving data.

[0025] The display device 30 displays the image generated by the control device 20. The display device 30 in this embodiment is a display.

[0026] [Display method] Hereinafter, an example of a process for displaying an image showing a local behavior of the tire contact patch on the display device 30 will be described with reference to Fig. 3. Fig. 3 is a flowchart showing an example of a process procedure for displaying an image showing the behavior of the tire contact patch on the display device 30.

[0027] In step S1, the forces acting on the tire tread at a plurality of measurement points on the tire contact surface are detected. In detail, in step S1, the forces acting on the tire tread at a plurality of measurement points on the tire contact surface are detected, and time series data of the forces at each measurement point is obtained. In this embodiment, a single measurement test using the measurement device 10 detects the force acting on the tire tread at one measurement point, so multiple measurement tests are performed by changing the position of the measurement point. By performing a single measurement test for each measurement point, the measurement device 10 can detect the force acting on the tire tread at each of the measurement points located at different positions on the tire contact surface. In addition, the measurement device 10 detects the force acting on the tire tread at each measurement point at multiple time points from when each measurement point on the tire contact surface of the test tire T comes into contact with the road plate 11 to when it leaves the road plate 11 in each measurement test.

[0028] In step S1, an image of the tire contact patch is acquired simultaneously with the detection of the force. In each measurement test, the measurement device 10 captures an image of the tire contact patch at each time point when the force acting on the tire tread at each measurement point is detected. That is, in step S1, time-series data of the image of the tire contact patch is acquired.

[0029] In step S2, the slippage at each measurement point at each time point is calculated based on the time series data of the image of the tire contact patch acquired in step S1. In detail, in step S2, the slippage at each measurement point at each time point is calculated based on the time series data of the image of the tire contact patch acquired in step S1, and time series data of the slippage at each measurement point is acquired. Specifically, the slippage calculation unit 13 of the measuring device 10 performs pattern matching based on the time series data of the image of the tire contact patch to calculate the slippage of each measurement point of the tire contact patch relative to the road plate 11 at each time point.

[0030] In step S3, the wear energy per unit time at each measurement point is calculated based on the force and slip at each measurement point at each time point. In detail, in step S3, the wear energy per unit time at each measurement point is calculated based on the time series data of the force and slip at each measurement point, and the time series data of the wear energy per unit time at each measurement point is obtained. Specifically, the control device 20 receives the time series data regarding the force and slip at each measurement point from the measurement device 10. The control device 20 calculates the wear energy per unit time at each measurement point based on the time series data received from the measurement device 10. Here, the "wear energy per unit time" in this specification is represented by the inner product of the force vector and the slip vector at each time point.

[0031] In step S4, the time series data on the force, slip, and wear energy obtained at each measurement point is matched in terms of the time relationship between the multiple measurement points. In this embodiment, the time series data on the force, slip, and wear energy at each measurement point (hereinafter, sometimes referred to as display data at each measurement point) is composed of data from when each measurement point on the tire contact surface of the test tire T comes into contact with the road plate 11 to when it leaves the road plate 11. Therefore, the time relationship between the multiple measurement points is not matched in terms of the display data. In this embodiment, the control device 20 matches the time relationship between the multiple measurement points in terms of the display data obtained at each measurement point by executing at least one of processes 1 and 2 described below.

[0032] <Process 1> The control device 20 sets one of the measurement points A1-A14 as a reference measurement point, and estimates the difference between the time when the reference measurement point contacts the tire contact surface and the time when each measurement point contacts the tire contact surface, based on the coordinates of the measurement points A1-A14 on the tire contact surface and the rotational speed of the test tire. The control device 20 reflects the estimated time difference in the display data, thereby matching the time relationships between the multiple measurement points for the display data obtained at each measurement point.

[0033] <Process 2> The control device 20 assumes or acquires the shape of the tire contact surface, and estimates the difference between the time when the reference measurement point contacts the tire contact surface and the time when each measurement point contacts the tire contact surface from the shape of the tire contact surface. The control device 20 reflects the estimated time difference in the display data, thereby matching the time relationship between the multiple measurement points for the display data obtained at each measurement point.

[0034] In step S5, a display result in which the force, slip, and wear energy at each measurement point are visually displayed is displayed on the display device 30. In this embodiment, a still image (hereinafter, sometimes referred to as a display image) in which the force, slip, and wear energy at each measurement point at the same time are superimposed on an image of the tire contact surface is displayed on the display device 30 as a display result. The control device 20 generates a display image by superimposing a force vector at each measurement point, a slip vector at each measurement point, and a figure representing the magnitude of wear energy per unit time at each measurement point at the same time on an image of the tire contact surface (hereinafter, sometimes referred to as an original image) that is the source for creating the display result. The control device 20 generates one display image for each time point. After that, data of the display image is transmitted from the control device 20 to the display device 30, and the display image is displayed on the display device 30. The display device 30 may selectively display display images at multiple times, or may display them simultaneously.

[0035] FIG. 4 shows a display image P1 at a specific time, which is an example of a display result displayed on the display device 30. Referring to FIG. 4, in the display image P1, a plurality of measurement points A1 to A14 represented by dots are displayed superimposed on the original image P2. In the display image P1, force vectors B1 to B14 corresponding one-to-one to the measurement points A1 to A14 are displayed superimposed on the original image P2. In the display image P1, slip vectors C1 to C14 corresponding one-to-one to the measurement points A1 to A14 are displayed superimposed on the original image P2. In the display image P1, figures (circles in this embodiment) representing the magnitudes of wear energies D1 to D14 corresponding one-to-one to the measurement points A1 to A14 are displayed superimposed on the original image P2. In the display image P1, the magnitudes of the wear energies D1 to D14 are represented by the sizes of the corresponding circles.

[0036] [effect] The display method of this embodiment provides the following advantages.

[0037] According to the display method of this embodiment, the magnitude and direction of the force and slip at a plurality of measurement points A1 to A14 on the tire contact patch are visually displayed, making it possible to evaluate local force and slip on the tire contact patch. When the magnitude and direction of the force and slip at a plurality of measurement points A1 to A14 on the tire contact patch while the tire is rolling are visually displayed as in this embodiment, it becomes possible to evaluate the uneven wear performance of the tire.

[0038] Generally, the wear performance of a tire is evaluated based on the wear energy at the tire contact surface. According to the display method of this embodiment, the magnitude of the wear energy per unit time at a plurality of measurement points A1 to A14 on the tire contact surface is visually displayed, making it possible to evaluate the local wear energy per unit time of the tire contact surface. In addition, by evaluating the wear energy per unit time at each time point from when the measurement points on the contact surface of the test tire T (shown in FIG. 2) come into contact with the road plate 11 to when they leave the road plate 11, it is possible to evaluate at which time point the magnitude of the wear energy affects the uneven wear performance.

[0039] The display method of this embodiment includes matching the time relationship between the multiple measurement points A1 to A14 for the time series data of force and slip acquired at each measurement point. This makes it possible to display the magnitude and direction of force and slip at the same time point at the multiple measurement points A1 to A14 in the display image, even in the case of single-point measurement in which time series data of force and slip at one measurement point is obtained by one measurement test as in this embodiment.

[0040] In the display method of this embodiment, a single measurement test using the measuring device 10 detects the force acting on the tire tread at one measurement point, so multiple measurement tests are performed by changing the position of the measurement point. By performing one measurement test for each measurement point, the measuring device 10 can detect the force acting on the tire tread at each of the measurement points at different positions on the tire contact surface. In this way, by performing a measurement test in which the force acting on the tire tread at one measurement point is detected multiple times by changing the position of the measurement point, the position of the measurement point on the tire contact surface can be set arbitrarily. As a result, it is possible to evaluate uneven wear performance by focusing on a specific position (for example, the leading side or trailing side) on the land part of the tread. In addition, according to the display method of this embodiment, compared to a display method using a force matrix sensor (FMS) or the like that measures the force and slip of the entire tire contact surface, it is possible to measure the force and slip using a measuring device with a simple configuration with fewer steps.

[0041] The display method according to the present disclosure is not limited to the configuration of the above embodiment, and various modifications are possible.

[0042] (First Modification) In the above embodiment, as an example of the display method according to the present disclosure, the wear energy per unit time at each measurement point is calculated and the wear energy per unit time at each measurement point is superimposed on the original image and displayed, but the display method according to the present disclosure is not limited to this. In the display method according to the first modification of the present disclosure, the cumulative wear energy from the start of contact at each measurement point, that is, the cumulative wear energy from when the measurement point on the tire contact surface comes into contact with the road plate 11, may be calculated and the cumulative wear energy at each measurement point may be displayed on the original image. According to the display method according to the first modification, the uneven wear performance of the tire can be evaluated by evaluating the local cumulative wear energy from when the measurement point on the tire contact surface of the test tire T (shown in FIG. 2) comes into contact with the road plate 11.

[0043] (Second Modification) In the above embodiment, as an example of the display method according to the present disclosure, the force, slip, and wear energy at each measurement point at a specific time are superimposed on the original image and displayed, but the display method according to the present disclosure is not limited to this. In the display method according to the second modification of the present disclosure, the force, slip, and wear energy at each measurement point may be superimposed on the original image and dynamically displayed in chronological order. In other words, in the display method according to the second modification of the present disclosure, a moving image in which the force, slip, and wear energy at each measurement point dynamically change in chronological order may be displayed. According to the display method according to the second modification, the force, slip, and wear energy at each measurement point on the tire contact surface of the test tire T (shown in FIG. 2) after each measurement point contacts the road plate 11 are visually displayed in chronological order, making it easier to evaluate the local behavior of the tire contact surface when the tire is rolling.

[0044] (Other variations) In the above embodiment, an example of the display method according to the present disclosure has been described in which the force vector, slip vector, and figures representing the wear energy per unit time at each measurement point are superimposed on the original image, but the display method according to the present disclosure is not limited to this. In the display method according to the present disclosure, only the force vector and slip vector at each measurement point may be superimposed on the original image.

[0045] In the above embodiment, the slippage is calculated by the measuring device 10, but the slippage may be calculated by the control device 20.

[0046] [Note] The display method according to the present disclosure provides the following aspects.

[0047] [Aspect 1] The display method according to the present disclosure includes: 1. A method for displaying forces and slip at a plurality of measurement points on a tire contact surface of a tire tread, comprising: Detecting a force acting on the tire tread at each measurement point when the tire is rolling; Acquiring an image of the tire contact surface simultaneously with the detection of the force; Calculating slip at each measurement point based on the image of the tire contact surface; A vector indicating the force at each measurement point and a vector indicating the slip at each measurement point are superimposed on the image of the tire contact surface and displayed. The present invention provides a display method, including:

[0048] [Aspect 2] The display method according to the present disclosure includes: Calculate the wear energy per unit time at each measurement point based on the force and slip at each measurement point; The wear energy per unit time at each measurement point is displayed on the image of the tire contact surface. The display method according to embodiment 1 further comprises:

[0049] [Aspect 3] The display method according to the present disclosure includes: Calculate the cumulative wear energy from the start of contact at each measurement point based on the force and slip at each measurement point; The accumulated wear energy at each measurement point is superimposed on the image of the tire contact surface. The display method according to embodiment 1 or 2 is further provided.

[0050] [Aspect 4] The display method according to the present disclosure includes: Detecting a force acting on the tire tread at each measurement point when the tire is rolling includes detecting forces at each measurement point at a plurality of times when the tire is rolling and obtaining time series data of the forces at each measurement point; Acquiring an image of the tire contact surface simultaneously with the detection of the force includes acquiring images of the tire contact surface at multiple time points when the force is detected, to acquire time-series data of the images of the tire contact surface, Calculating the slip at each measurement point based on the image of the tire contact surface includes calculating the slip at each measurement point at each time point based on time-series data of the image of the tire contact surface, and obtaining time-series data of the slip at each measurement point; The display method according to any one of aspects 1 to 3 further includes matching the temporal relationships among the multiple measurement points for the time series data of force and slip acquired at each measurement point before superimposing and displaying the vector indicating the force at each measurement point and the vector indicating the slip at each measurement point on the image of the tire contact surface.

[0051] [Aspect 5] The display method according to the present disclosure includes: The display method of embodiment 4 provides a display method in which the display of vectors indicating the force at each measurement point and vectors indicating the slippage at each measurement point are superimposed on the image of the tire contact surface, the display method including dynamically displaying vectors indicating the force at each measurement point and vectors indicating the slippage at each measurement point in chronological order superimposed on the image of the tire contact surface. [Explanation of symbols]

[0052] 1 Display System 10. Measuring Equipment 11 Road Plate 12 Tire behavior detection unit 12a Force detection unit 12b Ground surface imaging unit 13 Slip calculation section 20 Control device 21 Processors 22 Memory section 23 Transmitter / receiver 30 Display device

Claims

1. 1. A method for displaying tire contact behavior, comprising displaying forces and slip at a plurality of measurement points on a tire contact surface of a tire tread, the method comprising: Detecting a force acting on the tire tread at each measurement point when the tire is rolling; Acquiring an image of the tire contact surface simultaneously with the detection of the force; Calculating slip at each measurement point based on the image of the tire contact surface; A vector indicating the force at each measurement point and a vector indicating the slip at each measurement point are superimposed on the image of the tire contact surface and displayed. A method for displaying tire ground contact behavior, comprising:

2. Calculate the wear energy per unit time at each measurement point based on the force and slip at each measurement point; A graphic representing the magnitude of wear energy per unit time at each measurement point is superimposed on the image of the tire contact surface. The method for indicating the ground contact behavior of a tire according to claim 1 , further comprising:

3. Calculate the cumulative wear energy from the start of contact at each measurement point based on the force and slip at each measurement point; A graphic representing the magnitude of the accumulated wear energy at each measurement point is superimposed on the image of the tire contact surface. The method for indicating the ground contact behavior of a tire according to claim 1 , further comprising:

4. Detecting a force acting on the tire tread at each measurement point when the tire is rolling includes detecting forces at each measurement point at a plurality of times when the tire is rolling and obtaining time series data of the forces at each measurement point; Acquiring an image of the tire contact surface simultaneously with the detection of the force includes acquiring images of the tire contact surface at multiple time points when the force is detected, to acquire time-series data of the images of the tire contact surface, Calculating the slip at each measurement point based on the image of the tire contact surface includes calculating the slip at each measurement point at each time point based on time-series data of the image of the tire contact surface, and obtaining time-series data of the slip at each measurement point; 4. The method for displaying tire contact behavior according to claim 1, further comprising: matching a temporal relationship between the plurality of measurement points for time-series data of force and slip acquired at each measurement point before superimposing and displaying a vector indicating the force at each measurement point and a vector indicating the slip at each measurement point on the image of the tire contact surface.

5. 5. The method for displaying tire contact behavior as described in claim 4, wherein displaying vectors indicating the force at each measurement point and vectors indicating the slip at each measurement point superimposed on the image of the tire contact surface includes dynamically displaying vectors indicating the force at each measurement point and vectors indicating the slip at each measurement point superimposed on the image of the tire contact surface in chronological order.

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