JP7806478B2 - Measuring device and measuring method - Google Patents

Description

This disclosure relates to a measurement device for measuring tire contact patch stress and a measurement method using the test device.

Measuring devices for measuring tire contact patch stress are known. For example, Patent Document 1 below proposes a measuring device that measures tire contact patch stress using a sensor unit attached to a tire testing drum.

Japanese Patent Application Laid-Open No. 2019-203717

However, the measuring device in Patent Document 1 is unable to measure the tire's contact patch stress when the sensor protrusion of the sensor unit that comes into contact with the tire overlaps with the tire's lateral grooves, and accurate measurement can take a long time.

This disclosure was devised in light of the above-mentioned circumstances, and its primary objective is to provide a measurement device and measurement method that can accurately measure tire contact patch stress in a short period of time.

The present disclosure relates to a measuring device for measuring the contact patch stress of a tire, which includes a cylindrical drum having a running surface on which the tire runs, and a stress detection unit provided on a portion of the running surface, the stress detection unit including a detection surface with which the tire comes into contact, and the detection surface having a length in the drum circumferential direction that is greater than its width in the drum axial direction.

By having the above-described configuration, the measuring device disclosed herein can accurately measure tire contact patch stress in a short period of time.

FIG. 2 is a cross-sectional schematic view of the measuring device of the present embodiment. FIG. 2 is a partial perspective view of a measurement device including a stress detection unit according to the present embodiment. FIG. 10 is a development view showing the arrangement of stress detection units according to another embodiment. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. FIG. 10 is a schematic cross-sectional view of a stress detection unit according to another embodiment. FIG. 10 is a schematic cross-sectional view of a stress detection unit according to still another embodiment. 1 is a flowchart of a measurement method according to the present embodiment.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.
Fig. 1 is a cross-sectional schematic diagram showing a measuring device 1 of this embodiment. As shown in Fig. 1, the measuring device 1 of this embodiment is for measuring the contact patch stress of a tire T. Fig. 1 shows a passenger car tire as an example of the tire T to be measured, but the tire T is not limited to this, and the measuring device 1 can measure various tires T.

The tire T has, for example, multiple circumferential grooves t1 extending in the tire circumferential direction and multiple land portions t2 separated by the circumferential grooves t1. The tire T of this embodiment also has multiple lateral grooves t3 extending in the tire axial direction. For example, the lateral grooves t3 are provided in each of the multiple land portions t2. The land portions t2 of the tire T may be provided with, for example, sipes (not shown). Here, a sipe is a cut with a width of less than 2 mm perpendicular to the longitudinal direction, and is distinguished from a lateral groove t3 with a groove width of 2 mm or more.

The measuring device 1 of this embodiment includes a cylindrical drum 2 having a running surface 2a on which the tire T runs, and a stress detection unit 3 provided on part of the running surface 2a. The running surface 2a and stress detection unit 3 are provided, for example, on the inner circumferential surface of the drum 2.

The measuring device 1 preferably includes a tire support device 4 that supports the tire T so that it can rotate freely and move in the drum axial direction, and a drum support device 5 that rotates the drum 2. Such a measuring device 1 can measure the overall contact patch stress of the tire T by moving the tire T in the drum axial direction while running it over the stress detection unit 3.

Figure 2 is a partial perspective view of the measuring device 1 including the stress detection unit 3 of this embodiment. As shown in Figure 2, the stress detection unit 3 of this embodiment includes a detection surface 3a that comes into contact with the tire T. It is desirable that the length L of the detection surface 3a in the drum circumferential direction be greater than the width W of the detection surface 3a in the drum axial direction.

Such a detection surface 3a can measure the contact patch stress even if it overlaps with the lateral groove t3 of the tire T. Furthermore, because the detection surface 3a has a long contact time with the tire T, it can accurately measure the contact patch stress of the tire T. Therefore, the measurement device 1 in this embodiment can accurately measure the contact patch stress of the tire T in a short period of time.

In a more preferred embodiment, multiple stress detection units 3 are arranged in the drum axial direction. This type of measurement device 1 can measure the overall contact patch stress of the tire T even if the distance the tire T is moved in the drum axial direction is small, and measurements can be completed in a short time.

In this embodiment, the number of stress detection units 3 is equal to or greater than the number of land portions t2 extending in the circumferential direction of the tire T. Such stress detection units 3 can simultaneously measure the contact patch stress of each land portion t2, further shortening the time required for measurement.

Figure 3 is an exploded view showing the arrangement of the stress detection unit 3 in another embodiment. As shown in Figure 3, the stress detection unit 3 in this embodiment includes a first detection unit 3A and a second detection unit 3B that is spaced apart from the first detection unit 3A in the drum circumferential direction. In this embodiment, the first detection unit 3A and the second detection unit 3B are provided at different positions in the drum axial direction.

Such a stress detection unit 3 can reduce the distance that the tire T needs to be moved in the drum axial direction, and by arranging it so that there are no gaps in the drum axial direction, it is also possible to simultaneously measure the contact patch stress of the entire tire T. Therefore, the arrangement of the stress detection unit 3 in this embodiment is useful for measuring the contact patch stress of the tire T more accurately in a shorter time.

As shown in Figures 2 and 3, the length L of the detection surface 3a is preferably 10 mm or more. Having a length L of 10 mm or more for the detection surface 3a ensures sufficient contact time with the tire T and reduces the influence of the lateral grooves t3 and sipes of the tire T, allowing the contact patch stress of the tire T to be measured accurately in a short period of time. From this perspective, the length L of the detection surface 3a is more preferably 20 mm or more.

The length L of the detection surface 3a is preferably greater than the maximum groove width of the lateral groove t3 of the tire T. Such a stress detection unit 3 can reliably measure the contact patch stress even if the detection surface 3a overlaps the lateral groove t3 of the tire T.

The width W of the detection surface 3a is preferably less than 10 mm. Having a width W of the detection surface 3a of less than 10 mm increases the resolution in the tire axial direction, which helps to accurately measure the contact patch stress of the tire T. From this perspective, the width W of the detection surface 3a is more preferably 5 mm or less.

The width W of the detection surface 3a is preferably smaller than the minimum groove width of the circumferential groove t1 of the tire T. Such a stress detection unit 3 can reliably detect the circumferential groove t1 of the tire T, and is useful for accurately measuring the contact patch stress of the tire T.

As shown in Figure 2, the contour of the detection surface 3a is, for example, elliptical. This type of stress detection unit 3 can average and measure a force even if it acts locally on a portion of the detection surface 3a, which is useful for measuring the contact patch stress of the tire T in a short period of time.

As shown in Figure 3, the contour of the detection surface 3a may be, for example, rectangular. Such a detection surface 3a can measure a wider area at once, allowing the contact patch stress of the tire T to be measured in a shorter time.

If the detection surface 3a has a rectangular contour, it is desirable that the corners be chamfered. The detection surface 3a may also have an oval contour, for example. Such a detection surface 3a can reduce false detections caused by chipped or caught corners, and is useful for accurately measuring the contact patch stress of the tire T.

Figure 4 is a schematic cross-sectional view taken along line A-A in Figure 2. As shown in Figure 4, the stress detection unit 3 of this embodiment includes a three-component force sensor 3b that can detect the force acting on the detection surface 3a. This type of stress detection unit 3 is suitable for averaging and measuring the force acting on the detection surface 3a.

Figure 5 is a schematic cross-sectional view of a stress detection unit 6 in another embodiment. As shown in Figure 5, the stress detection unit 6 includes, for example, a detection surface 6a whose length L in the drum circumferential direction is greater than the drum axial width W (shown in Figure 2), and a six-component force sensor 6b that can detect the force and moment acting on the detection surface 6a. Such a stress detection unit 6 can also accurately measure the contact length of the contact patch of the tire T.

Figure 6 is a schematic cross-sectional view of a stress detection unit 7 in yet another embodiment. As shown in Figure 6, the stress detection unit 7 includes, for example, a detection surface 7a whose length L in the drum circumferential direction is greater than the width W in the drum axial direction (shown in Figure 2), and two three-component force sensors 7b arranged apart from the detection surface 7a in the drum circumferential direction. This type of stress detection unit 7 can also detect forces and moments acting on the detection surface 7a.

Next, a measurement method for measuring the contact patch stress of tire T using the above-described measurement device 1 will be described with reference to Figures 1 and 2. The measurement method for measuring the contact patch stress of tire T in this embodiment is performed using measurement device 1, so the contact patch stress of tire T can be measured accurately in a short period of time.

Figure 7 is a flowchart of the measurement method of this embodiment. As shown in Figure 7, the measurement method of this embodiment first performs a preparation step S1 in which the tire T to be measured is mounted on the measurement device 1. In the preparation step S1, it is desirable to apply a predetermined load to the tire T.

In the measurement method of this embodiment, after the preparation step S1, a running step S2 is performed in which the drum 2 is rotated so that the tire T runs on the running surface 2a. In the running step S2, it is desirable to rotate the drum 2 at a predetermined speed. In the running step S2, for example, the tire support device 4 is moved in the drum axial direction to change the contact position between the detection surface 3a and the tire T. This running step S2 can quantitatively measure the contact patch stress of the tire T.

In this embodiment, the measurement method involves a measurement step S3 in which the contact patch stress of the tire T traveling in the traveling step S2 is measured. The measurement step S3 measures, for example, the contact pressure, longitudinal force, and lateral force of the tire T passing over the detection surface 3a. It is desirable that the measurement step S3 combines measurement data of the tire T that has moved in the drum axial direction in the traveling step S2 to determine the overall contact patch stress of the tire T. This type of measurement step S3 can accurately measure the contact patch stress of the tire T in a short period of time.

In this embodiment, measurement step S3 is performed using a stress detection unit 3 whose detection surface 3a has a length L greater than the maximum groove width of the lateral groove t3. This type of measurement step S3 can reliably measure contact patch stress even if the detection surface 3a overlaps the lateral groove t3 of the tire T, and can shorten the time required for measurement.

In this embodiment, measurement step S3 is performed using a measurement device 1 in which the number of stress detection units 3 is equal to or greater than the number of land portions t2. This type of measurement step S3 can simultaneously measure the contact patch stress of each land portion t2, further shortening the time required for measurement.

The above describes in detail particularly preferred embodiments of the present disclosure, but the present disclosure is not limited to the above-described embodiments and can be modified and implemented in various ways.

[Note]
The present disclosure is as follows.

[Disclosure 1]
A measuring device for measuring the contact patch stress of a tire, comprising: a cylindrical drum having a running surface on which the tire runs; and a stress detection unit provided on a part of the running surface, wherein the stress detection unit includes a detection surface with which the tire comes into contact, and the length of the detection surface in the drum circumferential direction is greater than the width of the detection surface in the drum axial direction.

[Disclosure 2]
The measurement device described in Disclosure 1, wherein the detection surface has a rectangular outline.

[Disclosure 3]
The measurement device described in Disclosure 2, wherein the contour of the detection surface has chamfered corners.

[Disclosure 4]
The measurement device described in Disclosure 1, wherein the contour of the detection surface is elliptical.

[Disclosure 5]
The measuring device according to any one of Disclosures 1 to 4, wherein the detection surface has a length of 10 mm or more and a width of less than 10 mm.

[Disclosure 6]
The measuring device according to any one of claims 1 to 5, wherein the stress detection unit includes a three-component force sensor capable of detecting a force acting on the detection surface.

[Disclosure 7]
The measuring device described in the present disclosure 6, wherein the stress detection unit includes two of the three-component force sensors.

[Disclosure 8]
The measuring device according to any one of claims 1 to 5, wherein the stress detection unit includes a six-component force sensor capable of detecting forces and moments acting on the detection surface.

[Disclosure 9]
the stress detection unit includes a first detection unit and a second detection unit spaced apart from the first detection unit in the drum circumferential direction,
The measuring device according to any one of Disclosures 1 to 8, wherein the first detection unit and the second detection unit are provided at different positions in the drum axial direction.

[Disclosure 10]
A measurement method for measuring the contact patch stress of the tire using a measurement device described in any one of Disclosures 1 to 9.

[Disclosure 11]
The tire has lateral grooves extending in the tire axial direction,
The measurement method described in the present disclosure 10, wherein the length of the detection surface is measured by the stress detection unit, which is greater than the maximum groove width of the lateral groove.

[Disclosure 12]
The tire has a circumferential groove extending in a tire circumferential direction and a plurality of land portions separated by the circumferential groove,
12. The measurement method according to claim 10 or 11, wherein the measurement is performed using the measurement device in which the number of the stress detection portions is equal to or greater than the number of the land portions.

REFERENCE SIGNS LIST 1 Measuring device 2 Drum 2a Traveling surface 3 Stress detection unit 3a Detection surface

Claims (10)

A measuring device for measuring a tire contact patch stress, comprising:
a cylindrical drum having a running surface on which the tire runs, and a plurality of stress detection units provided on a part of the running surface,
each of the stress detection units includes a detection surface that comes into contact with the tire;
The length of the detection surface in the drum circumferential direction is greater than the width of the detection surface in the drum axial direction,
the plurality of stress detection portions include a first detection portion and a second detection portion spaced apart from the first detection portion in the drum circumferential direction,
The first detection unit and the second detection unit are provided at different positions in the drum axial direction .
Measuring equipment. The measurement device of claim 1, wherein the detection surface has a rectangular contour. The measurement device described in claim 2, wherein the corners of the detection surface are chamfered. The measurement device of claim 1, wherein the detection surface has an elliptical contour. The measurement device described in any one of claims 1 to 4, wherein the length of the detection surface is 10 mm or more and the width is less than 10 mm. The measuring device according to claim 1 , wherein each of the plurality of stress detection units includes a three-component force sensor capable of detecting a force acting on the detection surface. The measurement device according to claim 6 , wherein each of the plurality of stress detection units includes two of the three-component force sensors. 6. The measuring device according to claim 1, wherein each of the plurality of stress detection units includes a six-component force sensor capable of detecting a force and a moment acting on the detection surface. A measurement method for measuring a contact patch stress of a tire using a measurement device for measuring the contact patch stress of the tire, the method comprising:
the measuring device includes a cylindrical drum having a running surface on which the tire runs, and a stress detection unit provided on a part of the running surface,
the stress detection unit includes a detection surface that comes into contact with the tire,
The length of the detection surface in the drum circumferential direction is greater than the width of the detection surface in the drum axial direction,
The tire has a circumferential groove extending in a tire circumferential direction and a plurality of land portions separated by the circumferential groove,
The measurement is performed using the measuring device in which the number of the stress detection portions is equal to or greater than the number of the land portions.
Measurement method. The tire has lateral grooves extending in the tire axial direction,
The measurement method according to claim 9 , wherein the length of the detection surface is greater than a maximum groove width of the lateral groove by the stress detection unit.