Tire performance evaluation method

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

[Technical field]

[0001] The present invention relates to a method for evaluating tire performance. [Background technology]

[0002] The following Patent Document 1 describes a bench test method using a bench test device having a road surface. In the bench test method, a tire is placed in contact with the road surface and the running performance during cornering is tested. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-167575 A Summary of the Invention [Problem to be solved by the invention]

[0004] In general, the road surface on which a tire is test-driven changes or deteriorates due to contact with the tire or due to aging. Therefore, in order to accurately evaluate tire performance, it is necessary to maintain the surface condition of the road surface in a constant state.

[0005] The present invention has been devised in view of the above problems, and has as its main object to provide a tire evaluation method capable of evaluating tire performance with high accuracy. [Means for solving the problem]

[0006] The present invention is an evaluation method for evaluating tire performance, comprising a preparation step of preparing a driving road surface on which a test tire is run, a test step of running the test tire on the driving road surface to obtain test results, and an evaluation step of evaluating tire performance based on the test results, wherein the preparation step includes a first measurement step of measuring a first performance value for identifying the surface condition of the driving road surface, and, if the first performance value is not within a predetermined first range, an adjustment step of adjusting the surface condition of the driving road surface so that the first performance value is within the first range.

[0007] In the tire performance evaluation method according to the present invention, it is preferable that the first performance value is a physical quantity related to friction of the traveling road surface.

[0008] In the tire performance evaluation method according to the present invention, the first performance value is preferably a skid resistance value.

[0009] In the method for evaluating tire performance according to the present invention, the skid resistance value is preferably BPN (British Pendulum Number).

[0010] In the tire performance evaluation method according to the present invention, it is preferable that the first measurement step measures the first performance value at a plurality of points on the traveling road surface.

[0011] In the tire performance evaluation method according to the present invention, it is preferable that the adjustment step includes a step of reducing a surface roughness of the traveling road surface, or a step of sprinkling a fluid on the traveling road surface.

[0012] In the tire performance evaluation method according to the present invention, the preparation step desirably includes a second measurement step of measuring the first performance value again after the adjustment step.

[0013] In the tire performance evaluation method according to the present invention, it is desirable that the preparation step includes a break-in step of running a reference tire on the traveling road surface to break in the traveling road surface when the first performance value is within the first range after the second measurement step.

[0014] In the tire performance evaluation method according to the present invention, the break-in step desirably includes a third measurement step of measuring a second performance value for identifying the surface condition of the traveled road surface with the reference tire.

[0015] In the tire performance evaluation method according to the present invention, it is preferable that, in the break-in step, when the second performance value is not within a predetermined second range, the third measurement step is further carried out.

[0016] In the tire performance evaluation method according to the present invention, the second performance value is preferably a physical quantity relating to friction of the traveling road surface.

[0017] In the tire performance evaluation method according to the present invention, the second performance value is preferably a coefficient of sliding friction.

[0018] In the tire performance evaluation method according to the present invention, it is desirable that the break-in process includes a fourth measurement process of measuring the first performance value on the traveling road surface when the second performance value is within a predetermined second range.

[0019] In the method for evaluating tire performance according to the present invention, it is preferable that the surface of the traveling road surface is made of a metallic material. Effect of the Invention

[0020] The tire evaluation method of the present invention employs the above-mentioned configuration, making it possible to measure tire performance with high accuracy. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view for conceptually explaining one embodiment of an evaluation method of the present invention. [Diagram 2] FIG. 2 is a plan view for conceptually explaining a traveling road surface. [Diagram 3] 2 is a flowchart of an evaluation method according to the present embodiment. [Figure 4] 4 is a flowchart of a preparation process according to the present embodiment. [Diagram 5] 4 is a flowchart of a break-in process according to the present embodiment. [Figure 6] 4 is an example of a test result obtained in a test process of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view for conceptually explaining a tire performance evaluation method according to the present embodiment. As shown in Fig. 1, the evaluation method according to the present embodiment involves running a vehicle 10 equipped with a tire 1 on a road surface 3 to evaluate tire performance. Note that the present invention is not limited to this embodiment, and can also be applied to, for example, a tire performance evaluation method using a drum testing machine (not shown) of a well-known structure having a simulated road surface.

[0023] In this specification, a method for evaluating sliding friction performance will be described as a tire performance. Note that the present invention is not limited to sliding friction performance, and can be applied to methods for evaluating various tire performances, such as ride comfort performance and traction performance.

[0024] The vehicle 10 is fitted with, for example, two front tire 1a, two rear tire 1b, and one auxiliary tire 1c disposed rearward of the rear tire 1b. The auxiliary tire 1c has, for example, a smaller diameter and width than the rear tire 1b. Note that the auxiliary tire 1c is not limited to this embodiment. In this specification, "rear" refers to the side opposite to the vehicle traveling direction F. Also, "forward" refers to the vehicle traveling direction F.

[0025] The vehicle 10 of this embodiment includes a measuring tool 7 having a known structure for measuring tire performance, and a control tool 8 having a known structure for storing, determining, controlling, etc., information related to the measured tire performance. However, the vehicle 10 is not limited to this embodiment.

[0026] The control tool 8 includes, for example, a calculation unit consisting of a CPU (Central Processing Unit), a storage unit in which control procedures and programs are stored in advance, and a working memory into which the control procedures are read from the storage unit (not shown). The control tool 8 may be provided with a display unit for displaying processing results and the like, and an operation unit for an operator to operate. As such a control tool 8, for example, a well-known programmable sequencer, a microcomputer, a personal computer, or the like is desirable. The control tool 8 stores, for example, information relating to a first range P1 and a second range P2, which will be described later.

[0027] FIG. 2 is a plan view of the road surface 3. As shown in FIG. 2, the road surface 3 of this embodiment has a surface 3a with which the tire 1 comes into contact while traveling. The surface 3a is made of, for example, a metal material. The metal material is preferably made of, for example, steel. Such a road surface 3 can be used for a long period of time. In addition, the road surface 3 made of steel has a small sliding friction force with the tire 1, and it is easy to reproduce, for example, a traveling condition on ice. Note that the road surface 3 made of steel may have rust or scratches on its surface 3a due to adhesion of water or deterioration over time. The road surface 3 has, for example, a length L1 in the vehicle travel direction F of 18 to 22 m and a width W1 perpendicular to the vehicle travel direction F of 1800 to 2200 mm.

[0028] In this embodiment, the surface 3a includes a first region 4 with which the left tire (shown in FIG. 1) of the two rear tires 1b comes into contact during traveling. The first region 4 has, for example, a length L2 in the vehicle traveling direction F of 13 to 17 m and a width W2 perpendicular to the vehicle traveling direction F of 400 to 700 mm. In this specification, the "left side" means the left side when facing the vehicle traveling direction F.

[0029] Fig. 3 is a flowchart of the evaluation method of this embodiment. As shown in Fig. 3, the evaluation method of this embodiment includes a preparation step S1, a testing step S2, and an evaluation step S3. The preparation step S1 is a step of preparing a traveling road surface 3. The testing step S2 is a step of running a test tire (not shown) on the traveling road surface 3 prepared in the preparation step S1 to obtain test results. The evaluation step S3 is a step of evaluating tire performance based on the test results obtained in the testing step S2.

[0030] Fig. 4 is a flowchart of the preparation step S1. As shown in Fig. 4, the preparation step S1 of this embodiment includes a first measurement step S11 and an 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.

[0031] In the first measurement step S11 of this embodiment, a first performance value K1 is measured to identify the surface condition of the traveled road surface 3. In this embodiment, the first performance value K1 is measured at a plurality of points on the traveled road surface 3. The first performance value K1 is measured on the first region 4, for example.

[0032] The first performance value K1 is, for example, a physical quantity related to the friction of the traveled road surface 3. For example, a skid resistance value is used as such a physical quantity. Note that, as the first performance value K1, a physical quantity related to vibration or load may also be used.

[0033] In this embodiment, the skid resistance value is BPN (British Pendulum Number). In this embodiment, the BPN is measured by a method using a well-known Portable Skid Resistance Tester (for example, manufactured by MASTRAD) (not shown). The BPN is about 100 times larger than the sliding friction coefficient μ. The skid resistance value may also be measured by a method using a well-known Dynamic Friction Tester.

[0034] The BPN is measured at a plurality of measurement points t, for example, four measurement points t in this embodiment, spaced apart at a pitch p1 (shown in FIG. 2) equal to the vehicle travel direction F on the first area 4. The pitch p1 is preferably, for example, 3 to 5 m.

[0035] In the first judgment step S12 of this embodiment, it is judged whether or not the first performance value K1 measured in the first measurement step S11 is within a predetermined first range P1. In the first judgment step S12, for example, it is judged by the control tool 8 whether or not the first performance value K1 is within the first range P1. For example, a BPN of 25 to 30 is adopted as the first range P1. When the BPN is in the range of 25 to 30, the friction state of a wet iron plate is reproduced.

[0036] If 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. If it is determined in the first determination step S12 that the first performance value K1 is within the first range P1 (Y in FIG. 3), the break-in step S16 is performed.

[0037] In the adjustment step S13 of this embodiment, the surface condition of the travel road surface 3 is adjusted so that the first performance value K1 falls within the first range P1. In this embodiment, at each measurement point t in the first region 4, the first performance value K1 is adjusted to fall within the first range P1.

[0038] In the adjustment step S13, for example, when the BPN exceeds the first range P1, a fluid is sprayed onto the travel road surface 3. The fluid is preferably, for example, water, but may be industrial lubricating oil or the like. Furthermore, when the BPN exceeds the first range P1, the surface 3a of the travel road surface 3 is polished. This reduces the surface roughness of the travel road surface 3, and the BPN is reduced. Furthermore, when the BPN is smaller than the first range P1, for example, the surface 3a of the travel road surface 3 is polished by a well-known blasting process so as to increase the BPN, and the surface roughness is increased.

[0039] In the second measurement step S14 of the present embodiment, the first performance value K1 is measured again. In the second measurement step S14, the first performance value K1 is measured at each measurement point t of the first region 4, for example, by the same measurement method as in the first measurement step S11.

[0040] In the second determination step S15 of this embodiment, it is determined whether the first performance value K1 measured in the second measurement step S14 is within the first range P1. In the second determination step S15, the first performance value K1 is determined, for example, by the same determination method as in the first determination step S12.

[0041] In the second determination step S15, if 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. If 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.

[0042] The break-in process S16 is a process of running a reference tire 1T (shown in FIG. 1) on the traveling road surface 3 to break in the traveling road surface 3. Fig. 5 is a flowchart of the break-in process S16. As shown in Fig. 5, the break-in process S16 of this embodiment includes a third measurement process T1, a third judgment process T2, and a fourth measurement process T3.

[0043] In the third measurement step T1, in this embodiment, a second performance value K2 is measured to identify the surface condition of the travel road surface 3. In the third measurement step T1, as shown in FIG. 1, a vehicle 10 having an auxiliary tire 1c is used.

[0044] In the third measurement step T1 of this embodiment, a vehicle 10 is used that has a reference tire 1T mounted on the left rear tire 1b. 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 runs through the first region 4.

[0045] 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 the load or vibration acting on the traveling road surface 3. In this embodiment, the second performance value K2 is the sliding friction coefficient μ. The sliding friction coefficient μ is a friction coefficient with respect to the sliding speed V, and is calculated from the vertical load Fz and the longitudinal force Fx acting on the reference tire 1T during traveling. In this specification, the sliding friction coefficient μ is expressed by the following equation. Sliding friction coefficient μ=Fx / Fz

[0046] The slip velocity V is calculated as the difference (V2-V1) between the velocity V1 of the vehicle 10 and the peripheral velocity V2 of the reference tire 1T.

[0047] A load sensor is used as the measuring tool 7 for measuring the vertical load Fz and the longitudinal force Fx. For example, a well-known six-component force gauge is preferably used as the load sensor. The sliding friction coefficient μ is preferably measured when the sliding speed V is in the range of 1 to 30 km / h, and more preferably in the range of 1.8 to 24 km / h.

[0048] The reference tire 1T is preferably, for example, a slick tire (not shown) having no grooves on the tread surface 5 of the tread portion, or a tire having only a plurality of circumferential grooves G on the tread surface 5. In this embodiment, the circumferential grooves G extend continuously in a straight line in the circumferential direction of the tire. 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.

[0049] In the present embodiment, the third determination step T2 is to determine whether the second performance value K2 is within a predetermined second range P2. In the third determination step T2, the second performance value K2 is determined by the control device 8, for example.

[0050] The second range P2 is, for example, a range in which the coefficient of variation Cv of the sliding friction coefficient μ (Cv value) is within 6%. The smaller the Cv value, the more uniform the surface condition of the traveled road surface 3 is maintained, and the more accurately the tire performance of the test tire (not shown) can be measured. The coefficient of variation Cv is calculated by the following formula. Coefficient of variation Cv = (standard deviation σ) / (average value of sliding friction coefficient μ)

[0051] When the coefficient of variation Cv is used as the second range P2, it is desirable to measure the sliding friction coefficient μ at a plurality of locations (for example, seven locations) at approximately equal intervals in the tire circumferential direction.

[0052] If 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. If 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), a fourth measurement step T3 is performed.

[0053] In the fourth measurement step T3 in this embodiment, a first performance value K1 is measured on the travel 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.

[0054] Next, a testing process S2 is performed. In the testing process S2 of this embodiment, the vehicle 10 and the road surface 3 shown in FIG. 1 are used. In the testing process S2 of this embodiment, a test tire (not shown) is mounted on the left rear tire 1b. Then, the vehicle 10 is operated so that the test tire passes through the first area 4, and a second performance value K2 of the test tire on the first area 4 is measured. In the testing process S2, the second performance value K2 is measured, for example, in the same manner as in the third measurement process T1. FIG. 6 is an example of a graph showing the relationship between the sliding speed V and the sliding friction coefficient μ measured in the testing process S2.

[0055] In this embodiment, it is preferable to use a tire having the same tread pattern as the right rear tire 1b as the test tire.

[0056] Next, an evaluation step S3 is performed in which tire performance is evaluated based on the second performance value K2 obtained in the testing step S2. In this embodiment, a known method is adopted for the testing step S2 and the evaluation step S3. As described above, in this embodiment, tire performance is tested in the first region 4 where the surface condition of the traveling road surface 3 is maintained in a constant state, so that tire performance can be evaluated with high accuracy.

[0057] Although a 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 and carried out in various forms. [Explanation of symbols]

[0058] 3. Road surface S1 Preparation process S11 1st measurement process S13 Adjustment process S2 Testing process S3 Evaluation process K1 First performance value P1 1st range

Claims

1. An evaluation method for evaluating tire performance, comprising: A preparation step of preparing a road surface on which the test tire is to run; a test step of running the test tire on the running road surface to obtain a test result; and evaluating tire performance based on the test results, The preparation step includes a first measurement step of measuring a first performance value for identifying a surface condition of the travel road surface; and if the first performance value is not within a predetermined first range, adjusting the surface condition of the travel road surface so that the first performance value is within the first range. the preparation step includes a second measurement step of measuring the first performance value again after the adjustment step, the preparation step includes a break-in step of running a reference tire on the traveling road surface to break the reference tire in when the first performance value is within the first range after the second measurement step, How tire performance is evaluated.

2. The tire performance evaluation method according to claim 1 , wherein the first performance value is a physical quantity related to friction of the traveling road surface.

3. The tire performance evaluation method according to claim 1 , wherein the first performance value is a skid resistance value.

4. The tire performance evaluation method according to claim 3 , wherein the skid resistance value is BPN (British Pendulum Number).

5. The tire performance evaluation method according to claim 1 , wherein the first measurement step measures the first performance value at a plurality of points on the traveling road surface.

6. 6. The tire performance evaluation method according to claim 1, wherein the adjustment step includes a step of reducing a surface roughness of the traveling road surface, or a step of sprinkling a fluid on the traveling road surface.

7. A method for evaluating tire performance described in any one of claims 1 to 6, wherein the break-in process includes a third measurement process of measuring a second performance value for identifying the surface condition of the driving road surface using the reference tire.

8. A tire performance evaluation method as described in claim 7, wherein the break-in process further includes performing the third measurement process if the second performance value is not within a predetermined second range.

9. A method for evaluating tire performance as described in claim 7 or 8, wherein the second performance value is a physical quantity related to friction of the traveling road surface.

10. A method for evaluating tire performance described in any one of claims 7 to 9, wherein the second performance value is a sliding friction coefficient.

11. A method for evaluating tire performance described in any one of claims 7 to 10, wherein the break-in process includes a fourth measurement process of measuring the first performance value on the driving road surface when the second performance value is within a predetermined second range.

12. A method for evaluating tire performance described in any one of claims 1 to 11, wherein the surface of the road surface is a metal material.

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