JP2022090440A - Evaluation method for tire performance - Google Patents

Abstract

To provide an evaluation method for tire performance enabling the tire performance to be measured with high accuracy.SOLUTION: An evaluation method for tire performance is provided, including: a preparation step S1 of preparing a traveling road surface 3 on which a testing tire is traveled; a testing step S2 of traveling the testing tire on the prepared road surface and obtaining the result of the test; and an evaluation step S3 of evaluating the tire performance based on the result of the test. The preparation step S1 includes: a first measurement step S11 of measuring a first performance value K1 for identifying a surface condition of the road surface; and an adjustment step S13 of adjusting the road surface condition so that the first performance value K1 falls within a first range P1 when the value K1 is not in the first preset range P1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for evaluating tire performance.

The following Patent Document 1 describes a tabletop test method using a tabletop test device having a traveling road surface. In the bench test method, the running performance at the time of cornering is tested by grounding the tire on the running road surface.

Japanese Unexamined Patent Publication No. 2013-167575

In general, the road surface on which a tire is tested runs deteriorates or deteriorates due to contact with the tire and aging. Therefore, in order to accurately evaluate the tire performance, it is necessary to maintain the surface condition of the traveling road surface in a constant state.

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a tire evaluation method capable of accurately evaluating tire performance.

The present invention is an evaluation method for evaluating tire performance, which includes a preparatory step of preparing a traveling road surface on which a test tire is traveled, and a test step of traveling the test tire on the traveling road surface to obtain a test result. Including the evaluation step of evaluating the tire performance based on the test result, the preparatory step includes a first measurement step of measuring a first performance value for specifying the surface state of the traveling road surface, and the first measurement step. When the performance value is not within the predetermined first range, the adjustment step of adjusting the surface condition of the traveling road surface so that the first performance value is within the first range is included.

In the method for evaluating tire performance according to the present invention, it is desirable that the first performance value is a physical quantity related to friction on the traveling road surface.

In the method for evaluating tire performance according to the present invention, it is desirable that the first performance value is a slip resistance value.

In the method for evaluating tire performance according to the present invention, it is desirable that the slip resistance value is BPN (British Pendulum Number).

In the method for evaluating tire performance according to the present invention, it is desirable that the first measurement step measures the first performance value at a plurality of points on the traveling road surface.

It is desirable that the adjustment step according to the present invention includes a step of reducing the roughness of the surface of the traveling road surface or a step of sprinkling a fluid on the traveling road surface.

In the method for evaluating tire performance according to the present invention, it is desirable that the preparation step includes a second measurement step of measuring the first performance value again after the adjustment step.

In the method for evaluating tire performance according to the present invention, in the preparation step, after the second measurement step, when the first performance value is within the first range, the reference tire is run on the traveling road surface. It is desirable to include a break-in step of breaking in the traveling road surface.

It is desirable that the tire performance evaluation method according to the present invention includes a third measurement step in which the break-in step measures a second performance value for specifying the surface state of the traveling road surface with the reference tire.

In the method for evaluating tire performance according to the present invention, it is desirable that the third measurement step is further performed when the break-in step is not within the predetermined second range.

In the method for evaluating tire performance according to the present invention, it is desirable that the second performance value is a physical quantity related to friction on the traveling road surface.

In the method for evaluating tire performance according to the present invention, it is desirable that the second performance value is a sliding friction coefficient.

The method for evaluating tire performance according to the present invention is a fourth measurement in which the first performance value is measured on the traveling road surface when the second performance value is within a predetermined second range in the break-in step. It is desirable to include the process.

In the method for evaluating tire performance according to the present invention, it is desirable that the surface of the traveling road surface is made of a metal material.

By adopting the above configuration, the tire evaluation method of the present invention can accurately measure the tire performance.

It is a perspective view for conceptually explaining one Embodiment of the evaluation method of this invention. It is a top view for conceptually explaining a traveling road surface. It is a flowchart of the evaluation method of this embodiment. It is a flowchart of the preparation process of this embodiment. It is a flowchart of the break-in process of this embodiment. This is an example of the test results obtained in the test process of this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view for conceptually explaining a method for evaluating tire performance according to the present embodiment. As shown in FIG. 1, in the evaluation method of the present embodiment, the vehicle 10 on which the tire 1 is mounted is driven on the traveling road surface 3 to evaluate the tire performance. The present invention is not limited to such an aspect, and can be applied to, for example, a method for evaluating tire performance by a drum tester (not shown) having a well-known structure having a pseudo road surface.

In this specification, a method for evaluating slip friction performance is described as a tire performance. The present invention is not limited to the sliding friction performance, and can be applied to various tire performance evaluation methods such as riding comfort performance and traction performance, for example.

The vehicle 10 is equipped with, for example, two front wheel tires 1a, two rear wheel tires 1b, and one auxiliary tire 1c arranged behind the rear wheel tires 1b. As the auxiliary tire 1c, for example, a tire having a diameter and a width smaller than that of the rear wheel tire 1b is adopted. The auxiliary tire 1c is not limited to such an aspect. In the present specification, "rear" is opposite to the vehicle traveling direction F. Further, "forward" is the vehicle traveling direction F.

The vehicle 10 of the present embodiment includes a measuring tool 7 having a well-known structure for measuring tire performance, and a well-known structure controlling tool 8 for storing, determining, and controlling information on the measured tire performance. There is. The vehicle 10 is not limited to such an aspect.

The controller 8 includes, for example, a calculation unit including a CPU (central processing unit), a storage unit in which control procedures and programs are stored in advance, and a work memory in which control procedures are read from the storage unit. (Not shown). The controller 8 may be provided with a display unit for displaying the processing result and the like, and an operation unit for the operator to operate. As such a controller 8, for example, a well-known programmable sequencer, a microcomputer, a personal computer, or the like is desirable. The controller 8 stores, for example, information about the first range P1 and the second range P2, which will be described later.

FIG. 2 is a plan view of the traveling road surface 3. As shown in FIG. 2, the traveling road surface 3 of the present embodiment includes a surface 3a with which the traveling tire 1 contacts. The surface 3a is made of, for example, a metal material. As the metal material, for example, it is desirable that it is made of steel. Such a traveling road surface 3 can be used for a long period of time. Further, the steel traveling road surface 3 has a small sliding frictional force with the tire 1, and for example, it is easy to reproduce a traveling state on ice. The surface 3a of the steel traveling road surface 3 may be rusted or scratched due to the adhesion of water or deterioration over time. The traveling road surface 3 has, for example, a length L1 of the vehicle traveling direction F of 18 to 22 m and a width W1 orthogonal to the vehicle traveling direction F of 1800 to 2200 mm.

In the present embodiment, the surface 3a includes a first region 4 in which the tire (shown in FIG. 1) arranged on the left side of the two rear wheel tires 1b comes into contact with the tire during traveling. In the first region 4, for example, the length L2 in the vehicle traveling direction F is 13 to 17 m, and the width W2 orthogonal to the vehicle traveling direction F is 400 to 700 mm. In the present specification, "left side" means the left side in the direction of travel of the vehicle F.

FIG. 3 is a flowchart of the evaluation method of the present embodiment. As shown in FIG. 3, the evaluation method of the present embodiment includes a preparation step S1, a test step S2, and an evaluation step S3. The preparation step S1 is a step of preparing the traveling road surface 3. The test step S2 is a step of running a test tire (not shown) on the traveling road surface 3 prepared in the preparation step S1 and obtaining a test result. The evaluation step S3 is a step of evaluating the tire performance based on the test results obtained in the test step S2.

FIG. 4 is a flowchart of the preparation step S1. As shown in FIG. 4, the preparation step S1 of the present embodiment includes the first measurement step S11 and the adjustment step S13. The preparation step S1 may further include, for example, a first determination step S12, a second measurement step S14, a second determination step S15, and a break-in step S16.

In the first measurement step S11 of the present embodiment, the first performance value K1 for specifying the surface state of the traveling road surface 3 is measured. In the present embodiment, the first performance value K1 is measured at a plurality of points on the traveling road surface 3. The first performance value K1 is measured, for example, on the first region 4.

The first performance value K1 is, for example, a physical quantity related to the friction of the traveling road surface 3. As such a physical quantity, for example, a slip resistance value is adopted. As the first performance value K1, a physical quantity related to vibration or load may be adopted.

The slip resistance value is BPN (British Pendulum Number) in this embodiment. In this embodiment, BPN is measured by a method using a well-known Portable Skid Resistance Tester (for example, manufactured by MASTRAD) (not shown). BPN is about 100 times as large as the slip friction coefficient μ. The slip resistance value may be measured by a method using a well-known Dynamic Friction Tester.

The BPN is measured, for example, at a plurality of measurement points t separated by a pitch p1 (shown in FIG. 2) equal to the vehicle traveling direction F on the first region 4, or at four measurement points t in the present embodiment. The pitch p1 is preferably, for example, 3 to 5 m.

In the first determination step S12 of the present embodiment, it is determined whether or not the first performance value K1 measured in the first measurement step S11 is within the predetermined first range P1. In the first determination step S12, for example, whether or not the first performance value K1 is within the first range P1 is determined by the controller 8. As the first range P1, for example, 25 to 30 of BPN are adopted. When the BPN is at 25 to 30, the frictional state of the wet iron plate is reproduced.

When it is determined in the first determination step S12 that the first performance value K1 is not within the first range P1 (N in FIG. 3), the adjustment step S13 is performed. Further, in the first determination step S12, when it is determined that the first performance value K1 is within the first range P1 (Y in FIG. 3), the break-in step S16 is performed.

In the adjustment step S13 of the present embodiment, the surface condition of the traveling road surface 3 is adjusted so that the first performance value K1 is within the first range P1. In the present embodiment, the first performance value K1 is adjusted to be within the first range P1 at each measurement point t in the first region 4.

In the adjustment step S13, for example, when the BPN exceeds the range P1 of the first range, the fluid is sprinkled on the traveling road surface 3. As the fluid, for example, water is desirable, but industrial lubricating oil or the like may also be used. Further, when the BPN exceeds the range P1 of the first range, the surface 3a of the traveling road surface 3 is polished. As a result, the surface roughness of the traveling road surface 3 is reduced, and the BPN is reduced. Further, when the BPN is smaller than within the first range P1, for example, the surface 3a of the traveling road surface 3 is polished by a well-known blasting process so as to increase the BPN, and the surface roughness becomes large.

In the second measurement step S14 of the present embodiment, the first performance value K1 is measured again. In the second measurement step S14, for example, the first performance value K1 at each measurement point t in the first region 4 is measured by the same measurement method as in the first measurement step S11.

In the second determination step S15 of the present embodiment, it is determined whether or not the first performance value K1 measured in the second measurement step S14 is within the first range P1. In the second determination step S15, for example, the first performance value K1 is determined by the same determination method as in the first determination step S12.

In the second determination step S15, when it is determined that the first performance value K1 measured in the second measurement step S14 is within the first range P1 (Y in FIG. 4), the break-in step S16 is performed. Further, when it is determined that the first performance value K1 measured in the second measurement step S14 is not within the first range P1 (N in FIG. 4), the adjustment step S13 is performed again.

The break-in step S16 is a step of running the reference tire 1T (shown in FIG. 1) on the running road surface 3 to break-in the running road surface 3. FIG. 5 is a flowchart of the break-in step S16. As shown in FIG. 5, the break-in step S16 of the present embodiment includes a third measurement step T1, a third determination step T2, and a fourth measurement step T3.

In the third measurement step T1, in the present embodiment, the second performance value K2 for specifying the surface state of the traveling road surface 3 is measured. In the third measurement step T1, as shown in FIG. 1, a vehicle 10 having an auxiliary tire 1c is used.

In the third measurement step T1 of the present embodiment, the vehicle 10 in which the reference tire 1T is mounted on the left rear wheel tire 1b is used. In the third measurement step T1, for example, the vehicle 10 is driven so that the reference tire 1T passes through the first region 4. The auxiliary tire 1c is, for example, a tire for measuring the speed V1 of the vehicle 10. The reference tire 1T is, for example, a tire for measuring the second performance value K2. In the third measurement step T1, for example, it is desirable that the auxiliary tire 1c also travels in the first region 4.

The second performance value K2 is, for example, a physical quantity related to the friction of the traveling road surface 3. The second performance value K2 may be, for example, a physical quantity related to a load or vibration acting on the traveling road surface 3. The second performance value K2 is the sliding friction coefficient μ in the present embodiment. The slip friction coefficient μ is a friction coefficient with respect to the slip speed V, and is calculated from the vertical load Fz and the front-rear force Fx acting on the reference tire 1T during traveling. The slip friction coefficient μ is expressed by the following equation in the present specification.
Sliding friction coefficient μ = Fx / Fz

The slip speed V is calculated by the difference (V2-V1) between the speed V1 of the vehicle 10 and the peripheral speed V2 of the reference tire 1T.

A load sensor is adopted as a measuring tool 7 for measuring such a vertical load Fz and a front-back force Fx. As the load sensor, for example, a well-known six-component force meter is preferably adopted. The slip friction coefficient μ is preferably measured in the range of the slip speed V of 1 to 30 km / h, and more preferably in the range of 1.8 to 24 km / h.

As the reference tire 1T, for example, a slick tire (not shown) having no groove on the tread portion 5 of the tread portion, or a tire having only a plurality of circumferential grooves G on the tread portion 5 is desirable. As the circumferential groove G, in the present embodiment, a groove G that extends continuously and linearly in the tire circumferential direction is adopted. Such a reference tire 1T has a small change in rigidity on the tread surface 5, and is useful for accurately measuring the surface condition of the traveling road surface 3.

In the present embodiment, the third determination step T2 determines whether or not the second performance value K2 is within the predetermined second range P2. In the third determination step T2, for example, the second performance value K2 is determined by the controller 8.

As the second range P2, for example, it is adopted that the value (Cv value) of the coefficient of variation Cv of the slip friction coefficient μ is within 6%. The smaller the Cv value, the more the uniformity of the surface condition of the traveling road surface 3 is maintained, and the tire performance of the test tire (not shown) can be measured accurately. The coefficient of variation Cv is calculated by the following formula.
Coefficient of variation Cv = (standard deviation σ) / (mean value of slip friction coefficient μ)

When the coefficient of variation Cv is used as the second range P2, it is desirable that the slip friction coefficient μ is measured at a plurality of points (for example, 7 points) at substantially equal pitches in the tire circumferential direction.

When it is determined in the third determination step T2 that the second performance value K2 is not within the second range P2 (N in FIG. 5), the third measurement step T1 and the third determination step T2 are repeated again. When it is determined in the third determination step T2 that the second performance value K2 is within the second range P2 (Y in FIG. 5), the fourth measurement step T3 is performed.

In the fourth measurement step T3, in the present embodiment, the first performance value K1 is measured on the traveling road surface 3. In the fourth measurement step T3, for example, the BPN is measured by the same method as in the first measurement step S11, and it is confirmed that the BPN is within the first range P1.

Next, the test step S2 is performed. In the test step S2 of the present embodiment, the vehicle 10 and the traveling road surface 3 shown in FIG. 1 are used. In the test step S2, in the present embodiment, the test tire (not shown) is mounted on the left rear wheel tire 1b. Then, the vehicle 10 is operated so that the test tire passes through the first region 4, and the second performance value K2 of the test tire on the first region 4 is measured. In the test step S2, for example, the second performance value K2 is measured in the same manner as in the third measurement step T1. FIG. 6 is an example of a graph showing the relationship between the slip speed V measured in the test step S2 and the slip friction coefficient μ.

In the present embodiment, it is desirable that the test tire adopts a tire having the same tread pattern as the right rear wheel tire 1b.

Next, an evaluation step S3 in which the tire performance is evaluated is performed based on the second performance value K2 obtained in the test step S2. In the present embodiment, a well-known method is adopted for such a test step S2 and an evaluation step S3. As described above, in the present embodiment, the tire performance is tested in the first region 4 in which the surface condition on the traveling road surface 3 is maintained in a constant state, so that the tire performance can be evaluated accurately.

Although the particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified into various embodiments.

3 Traveling road surface S1 Preparation process S11 First measurement process S13 Adjustment process S2 Test process S3 Evaluation process K1 First performance value P1 First range

Claims (14)

It is an evaluation method for evaluating tire performance.
The preparatory process to prepare the road surface on which the test tires will run, and
A test process in which the test tire is run on the running road surface to obtain a test result, and
Including an evaluation process for evaluating tire performance based on the test results.
The preparation step includes a first measurement step of measuring a first performance value for specifying the surface state of the traveling road surface, and a first measurement step.
When the first performance value is not within the predetermined first range, the adjustment step of adjusting the surface condition of the traveling road surface so that the first performance value is within the first range is included.
How to evaluate tire performance. The method for evaluating tire performance according to claim 1, wherein the first performance value is a physical quantity related to friction on the traveling road surface. The method for evaluating tire performance according to claim 1 or 2, wherein the first performance value is a slip resistance value. The method for evaluating tire performance according to claim 3, wherein the slip resistance value is a BPN (British Pendulum Number). The method for evaluating tire performance according to any one of claims 1 to 4, wherein the first measurement step measures the first performance value at a plurality of points on the traveling road surface. The method for evaluating tire performance according to any one of claims 1 to 5, wherein the adjusting step includes a step of reducing the roughness of the surface of the traveling road surface or a step of sprinkling a fluid on the traveling road surface. .. The method for evaluating tire performance according to any one of claims 1 to 6, wherein the preparation step includes a second measurement step of measuring the first performance value again after the adjustment step. The preparatory step includes, after the second measurement step, a break-in step of running a reference tire on the traveling road surface to acclimatize the traveling road surface when the first performance value is within the first range. The method for evaluating tire performance according to claim 7. The tire performance evaluation method according to claim 8, wherein the break-in step includes a third measurement step of measuring a second performance value for specifying the surface state of the traveling road surface with the reference tire. The tire performance evaluation method according to claim 9, wherein the break-in step further performs the third measurement step when the second performance value is not within the predetermined second range. The method for evaluating tire performance according to claim 9, wherein the second performance value is a physical quantity related to friction on the traveling road surface. The method for evaluating tire performance according to any one of claims 9 to 11, wherein the second performance value is a sliding friction coefficient. Any of claims 9 to 12, wherein the break-in step includes a fourth measurement step of measuring the first performance value on the traveling road surface when the second performance value is within a predetermined second range. The method for evaluating tire performance according to item 1. The method for evaluating tire performance according to any one of claims 1 to 13, wherein the surface of the traveling road surface is made of a metal material.

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