Method for evaluating tire vibration characteristics

Abstract

To provide a tire vibration characteristic evaluation method which allows for accurately evaluating vibration characteristics of a tire when the tire goes over a protrusion on a plane.SOLUTION: A method of evaluating vibration characteristics of a tire 1 is provided. An axial force F1 exhibited when the tire 1 goes over a protrusion 3 provided on a plane 2 is derived from an axial force F2 exhibited when the tire 1 goes over a protrusion 5 provided on a running surface 4a of a running drum 4.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Conventionally, methods for evaluating tire vibration characteristics have been known. For example, Patent Document 1 below proposes a method for evaluating tire vibration characteristics from the axial force when the tire rides over a protrusion provided on the running surface of a running drum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-161412 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the test using a running drum as in Patent Document 1, it is not possible to evaluate the vibration characteristics when the tire goes over a protrusion on a flat surface that the tire comes into contact with during actual running, and only a relative evaluation against a reference tire is possible. Also, if an attempt is made to evaluate the vibration characteristics of a tire using an actual flat surface, it is necessary to prepare an enormous number of flat surfaces, making it difficult to perform an evaluation with high reproducibility.

[0005] The present invention has been devised in consideration of the above-described circumstances, and has as its main object to provide a tire vibration characteristic evaluation method capable of accurately evaluating the vibration characteristics of a tire when going over a protrusion on a flat surface. [Means for solving the problem]

[0006] The present invention is a method for evaluating the vibration characteristics of a tire, characterized in that the axial force when the tire goes over a protrusion provided on a flat surface is determined from the axial force when the tire goes over a protrusion provided on the running surface of a running drum.

[0007] In the method for evaluating vibration characteristics of a tire of the present invention, it is desirable to include a setting step of setting a rolling speed at which the tire runs on the running drum, a running step of running the tire on the running drum at the set rolling speed, a measuring step of measuring an axial force of the tire during the running step, and an evaluation step of determining, based on the measured axial force, the axial force at which the tire goes over the protrusion provided on the plane at an evaluation speed.

[0008] In the method for evaluating vibration characteristics of a tire of the present invention, it is desirable that the setting step includes a first step of determining a first contact length L1, which is the contact length in the tire circumferential direction when the tire in a normal state contacts the flat surface under a normal load, a second step of determining a second contact length L2, which is the contact length when the tire in a normal state contacts the running drum under a normal load, and a third step of setting the rolling speed based on the evaluation speed and the ratio (L2 / L1) of the first contact length L1 and the second contact length L2.

[0009] In the tire vibration characteristic evaluation method of the present invention, it is preferable that in the third step, the rolling speed is set as a product of the evaluation speed and the ratio (L2 / L1).

[0010] The method for evaluating vibration characteristics of a tire of the present invention desirably includes a preparation step of using a computer to set a tire model that reproduces the tire and a drum model that reproduces the running drum, a setting step of setting a rolling speed at which the tire model runs on the drum model, a running step of running the drum model at the set rolling speed, a measurement step of calculating an axial force of the tire model in the running step, and an evaluation step of determining, based on the calculated axial force, the axial force at which the tire goes over the protrusion provided on the plane at an evaluation speed.

[0011] In the tire vibration characteristic evaluation method of the present invention, it is desirable that the rolling speed is lower than the evaluation speed. Effect of the Invention

[0012] The tire vibration characteristic evaluation method of the present invention determines the axial force when the tire goes over a protrusion provided on a flat surface from the axial force when the tire goes over a protrusion provided on the running surface of a traveling drum. Since such a tire vibration characteristic evaluation method determines the axial force when the tire goes over a protrusion provided on a flat surface based on the axial force when the tire goes over a protrusion provided on a traveling drum, which has high reproducibility, the tire vibration characteristic can be evaluated with high accuracy. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic diagram showing an embodiment of a tire of the present invention when it rides over a protrusion provided on a flat surface. [Diagram 2] 2 is a schematic diagram showing the tire of FIG. 1 climbing over a protrusion provided on the running surface of a running drum. FIG. [Diagram 3] 1 is a flowchart of a method for evaluating vibration characteristics of a tire. [Figure 4] 13 is a flowchart of a setting process. [Diagram 5] FIG. 4 is a schematic diagram showing the ground contact surface in the first step. [Figure 6] FIG. 4 is a schematic diagram showing the ground contact surface in the second step. [Figure 7] 13 is a graph showing an example of a result of a road reaction force in a comparative example. [Figure 8] 13 is a graph showing an example of the results of axial vertical forces in a comparative example. [Figure 9] 13 is a graph showing an example of a result of a longitudinal force of an axis in a comparative example. [Figure 10] 13 is a graph showing an example of a result of a road reaction force in the embodiment. [Figure 11] 13 is a graph showing an example of the results of the vertical axial force in the embodiment. [Figure 12] 13 is a graph showing an example of the results of the vertical axial force in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic diagram showing a tire 1 of this embodiment climbing over a protrusion 3 provided on a plane 2, and Fig. 2 is a schematic diagram showing the tire 1 of Fig. 1 climbing over a protrusion 5 provided on a running surface 4a of a running drum 4. The tire 1 is suitably used, for example, as a pneumatic tire for a passenger vehicle. The tire 1 is not limited to a pneumatic tire for a passenger vehicle, and can be used for various tires such as a pneumatic tire for heavy loads, a pneumatic tire for a motorcycle, and an airless tire that is not filled with pressurized air inside.

[0015] As shown in Figures 1 and 2, the method for evaluating the vibration characteristics of tire 1 in this embodiment determines the axial force F1 when tire 1 goes over a protrusion 3 provided on a plane 2 from the axial force F2 when tire 1 goes over a protrusion 5 provided on the running surface 4a of a running drum 4.

[0016] Such a method for evaluating the vibration characteristics of a tire 1 determines the axial force F1 when the tire 1 goes over a protrusion 3 provided on a plane 2 based on the axial force F2 when the tire 1 goes over a protrusion 5 provided on a traveling drum 4, which has high reproducibility, and therefore allows the vibration characteristics of the tire 1 to be evaluated with high accuracy.

[0017] In a more preferred embodiment, the protrusion 3 on the plane 2 has a height of 2 to 20 mm and a square cross section. The protrusion 5 on the running surface 4a of the traveling drum 4 desirably has the same cross section as the protrusion 3 on the plane 2. Such a protrusion 5 of the traveling drum 4 is useful for accurately evaluating the vibration characteristics of the tire 1 when it goes over the protrusion 3 on the plane 2.

[0018] 3 is a flowchart of the vibration characteristic evaluation method of the tire 1 of this embodiment. The vibration characteristic evaluation method of the tire 1 of this embodiment includes a preparation step S1 of preparing the tire 1 and a running drum 4 having protrusions 5 provided on a running surface 4a. In the preparation step S1, for example, the tire 1 in a normal state and the running drum 4 as a bench test device are prepared.

[0019] Here, the "normal state" refers to, in the case where the tire 1 is a pneumatic tire, an unloaded state in which the tire 1 is mounted on a normal rim and adjusted to a normal internal pressure. In the case where the tire 1 is an airless tire, the "normal state" refers to an unloaded state determined by the manufacturer, etc. In addition, in this specification, unless otherwise specified, the dimensions of each part of the tire 1 are values ​​measured in the normal state.

[0020] A "genuine rim" is a rim that is determined for each tire by a standard system that includes the standard on which tire 1 is based, for example, "standard rim" for JATMA, "design rim" for TRA, and "measuring rim" for ETRTO. A "genuine rim" is a rim that is determined for each tire by the manufacturer, etc., when there is no standard system that includes the standard on which tire 1 is based.

[0021] "Normal internal pressure" is the air pressure set for each tire by a standard system that includes the standard on which tire 1 is based, such as "maximum air pressure" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "INFLATION PRESSURE" for ETRTO. "Normal internal pressure" is the air pressure set for each tire by the manufacturer, etc., if there is no standard system that includes the standard on which tire 1 is based.

[0022] In the method for evaluating vibration characteristics of a tire 1 according to the present embodiment, after the preparation step S1, a setting step S2 is performed in which a rolling speed V2 when the tire 1 runs on the running surface 4a of the running drum 4 is set. In the setting step S2, for example, in addition to the rolling speed V2, a load or the like for evaluation at a load different from the normal load may be set.

[0023] Here, the "normal load" is the load determined for each tire by each standard in a standard system including the standard on which the tire 1 is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. The "normal load" is the load determined for each tire by the manufacturer, etc., when there is no standard system including the standard on which the tire 1 is based.

[0024] Fig. 4 is a flowchart of the setting step S2. As shown in Fig. 4, the setting step S2 of this embodiment includes a first step S21 for determining a first contact length L1 (shown in Fig. 5) which is a contact length in the tire circumferential direction when the tire 1 in a normal state contacts the plane 2 with a normal load applied thereto.

[0025] Fig. 5 is a schematic diagram showing the contact surface 1a in the first step S21. As shown in Fig. 5, in the first step S21, for example, the tire 1 is placed on a sheet-like pressure sensor provided on a plane to obtain the first contact length L1. In the first step S21, for example, the tire 1 may be placed on a transparent flat plate to obtain the first contact length L1, or the first contact length L1 may be obtained by a simulation using a computer.

[0026] As shown in FIG. 4, the setting process S2 of this embodiment includes a first process S21 and a second process S22 for determining a second contact length L2 (shown in FIG. 6), which is the contact length when the tire 1 in a normal state comes into contact with the running drum 4 under a normal load.

[0027] Fig. 6 is a schematic diagram showing the contact surface 1b in the second step S22. As shown in Fig. 6, in the second step S22, for example, the tire 1 is brought into contact with a sheet-like pressure sensor provided on a curved surface having the same curvature as the traveling drum 4 to obtain the second contact length L2. In the second step S22, for example, the tire 1 may be brought into contact with a transparent curved plate to obtain the second contact length L2, or the second contact length L2 may be obtained by a simulation using a computer.

[0028] 4 to 6, in the setting step S2 of this embodiment, after the first step S21 and the second step S22, a third step S23 is performed in which the rolling speed V2 is set based on the evaluation speed V1 and the ratio (L2 / L1) of the first contact length L1 and the second contact length L2. Such a third step S23 is useful for determining the axial force F1 when the tire 1 goes over the protrusion 3 provided on the flat surface 2 from the axial force F2 when the tire 1 goes over the protrusion 5 provided on the running surface 4a of the running drum 4.

[0029] In the third step S23 of this embodiment, the rolling speed V2 is set to be smaller than the evaluation speed V1. As a result, the vibration characteristic evaluation method for the tire 1 of this embodiment can evaluate the axial force F2 when the tire 1 goes over the protrusion 5 provided on the running surface 4a of the running drum 4 as the axial force F1 when the tire 1 goes over the protrusion 3 provided on the flat surface 2 at the evaluation speed V1.

[0030] In the third step S23, it is preferable to set the rolling speed V2 as the product of the evaluation speed V1 and the ratio (L2 / L1). In such a third step S23, the rolling speed V2 can be set by a simple calculation, and a highly accurate evaluation can be easily performed.

[0031] 3, the method for evaluating vibration characteristics of a tire 1 according to this embodiment includes a running step S3 in which the tire 1 is caused to run on the running surface 4a of the running drum 4 at a set rolling speed V2, and a measurement step S4 in which the axial force F2 of the tire 1 during the running step S3 is measured. Such running step S3 and measurement step S4 provide high reproducibility of the axial force F2 when the tire 1 goes over the protrusion 5 provided on the running surface 4a of the running drum 4, and therefore the vibration characteristics of the tire 1 can be evaluated with high accuracy.

[0032] The vibration characteristic evaluation method for tire 1 of this embodiment includes an evaluation step S5 of determining, based on the measured axial force F2, the axial force F1 when tire 1 passes over protrusion 3 provided on flat surface 2 at evaluation speed V1. The axial force F1 when tire 1 of this embodiment passes over protrusion 3 provided on flat surface 2 at evaluation speed V1 is determined as the axial force F2 when tire 1 passes over protrusion 5 provided on running surface 4a of running drum 4 at rolling speed V2. Such a vibration characteristic evaluation method for tire 1 can easily obtain an accurate evaluation of the vibration characteristic of tire 1.

[0033] In another embodiment of the method for evaluating vibration characteristics of a tire 1, the evaluation is performed by simulation using a computer. In the preparation step S1 of the other embodiment, a tire model that reproduces the tire 1 and a drum model that reproduces the running drum 4 are set using a computer. The drum model preferably includes a protrusion model that reproduces the protrusion 5. This method for evaluating vibration characteristics of a tire 1 does not require the preparation of an actual tire 1 or running drum 4, and can easily perform many evaluations with different conditions.

[0034] In the setting step S2 of another embodiment, a rolling speed V2 when the tire model runs on the drum model is set. The setting step S2 is preferably performed in the first step S21 to the third step S23 shown in Fig. 4. Such a setting step S2 is useful for determining the axial force F1 when the tire 1 goes over a protrusion 3 provided on the plane 2 from the axial force F2 when the tire model goes over a protrusion model provided on the drum model.

[0035] In another embodiment, the running step S3 involves running the tire model on a drum model at a set rolling speed V2. In another embodiment, the measurement step S4 involves calculating the axial force F2 of the tire model in the running step S3. In such a running step S3 and measurement step S4, the calculation load of the axial force F2 when going over a protrusion model provided on the drum model is small, so that it is possible to perform a calculation taking into account the influence of multiple disturbances, and it is possible to accurately evaluate the vibration characteristics of the tire 1.

[0036] In the evaluation step S5 of the other embodiment, the axial force F1 when the tire 1 goes over the protrusion 3 provided on the plane 2 at the evaluation speed V1 is calculated based on the calculated axial force F2. Such a method for evaluating the vibration characteristics of the tire 1 can easily obtain an accurate evaluation of the vibration characteristics of the tire 1.

[0037] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment and can be modified in various ways. EXAMPLES

[0038] Tests were conducted on the embodiment of the tire vibration characteristic evaluation method shown in Figures 1 to 6. As a comparative example, a test was conducted in which a traveling drum was run at an evaluation speed. In addition, as an evaluation standard, a standard test was conducted in which a protrusion was provided on a flat surface and the drum was run. The common specifications and test method are as follows.

[0039] <Common specifications> Tire size: 205 / 60R16 Rim size: 16×6J Air pressure: 220kPa Load: 4.5kN Rated speed: 40km / h Protrusion height: 5mm Protrusion cross-sectional shape: square

[0040] <Comparative Example Test> The upper and lower road reaction forces and axial force were measured when the vehicle went over a protrusion on the traveling drum at an evaluation speed of 40 km / h. The axial force was measured as an up-down axle force and axle longitudinal force. The test results of the comparative example are shown as symbol A in Figs. 7 to 9. Fig. 7 is a graph showing an example of the results of the up-down road reaction forces of the comparative example, Fig. 8 is a graph showing an example of the results of the up-down axle force of the comparative example, and Fig. 9 is a graph showing an example of the results of the longitudinal axle force of the comparative example. The horizontal axes of Figs. 7 to 9 each represent time.

[0041] <Testing of the Example> The first contact length when the tire touched a flat surface and the second contact length when the tire touched a curved surface with the same curvature as the running drum were measured. Since the first contact length was 155 mm and the second contact length was 135 mm, the rolling speed was set to 40 km / h x (135 mm / 155 mm) = 34.8 km / h.

[0042] Then, the upper and lower road reaction forces and the axial force were measured when the vehicle went over a protrusion on the traveling drum at a set speed of 34.8 km / h. The axial forces were measured as the vertical axle force and the longitudinal axle force. The test results of the embodiment are shown as B in Figs. 10 to 12. Fig. 10 is a graph showing an example of the results of the vertical road reaction forces of the embodiment, Fig. 11 is a graph showing an example of the results of the vertical axle force of the embodiment, and Fig. 12 is a graph showing an example of the results of the longitudinal axle force of the embodiment. The horizontal axes of Figs. 10 to 12 respectively represent time.

[0043] <Testing criteria> The vertical road reaction forces and axial force were measured when the vehicle went over a protrusion on a flat surface at an evaluation speed of 40 km / h. The axial force was measured as vertical axle force and longitudinal axle force. The results of the evaluation criteria test are shown as C in Figures 7 to 12.

[0044] As a result of the test, it was confirmed that the waveforms of the road reaction force and axial force of the embodiment were equivalent to the evaluation standards, and compared to the comparative example, it was possible to accurately evaluate the vibration characteristics of a tire when going over a protrusion on a flat surface. [Explanation of symbols]

[0045] 1 Tire 2 planes 3 protrusions 4 Traveling drum 4a Running surface 5 protrusions

Claims

1. 1. A method for evaluating vibration characteristics of a tire, comprising: The axial force when the tire goes over a protrusion provided on a flat surface is calculated from the axial force when the tire goes over a protrusion provided on the running surface of a running drum, A setting step of setting a rolling speed when the tire runs on the running drum; a running step of running the tire on the running drum at the set rolling speed; a measuring step of measuring an axial force of the tire during the running step; and an evaluation step of determining an axial force when the tire goes over the protrusion provided on the plane at an evaluation speed based on the measured axial force, The setting step includes: A first step of determining a first contact length L1, which is a contact length in a tire circumferential direction when the tire in a normal state contacts the flat surface with a normal load applied thereto; A second step of determining a second contact length L2, which is a contact length when the tire in a normal state is in contact with the traveling drum under a normal load; and a third step of setting the rolling speed based on the evaluated speed and a ratio (L2 / L1) of the first contact length L1 to the second contact length L2. Method for evaluating tire vibration characteristics.

2. 2. The method for evaluating vibration characteristics of a tire according to claim 1, wherein the third step sets the rolling speed as a product of the evaluation speed and the ratio (L2 / L1).

3. A method for evaluating vibration characteristics of a tire, comprising: The axial force when the tire goes over a protrusion provided on a flat surface is calculated from the axial force when the tire goes over a protrusion provided on the running surface of a running drum, A setting step of setting a rolling speed when the tire runs on the running drum; a running step of running the tire on the running drum at the set rolling speed; a measuring step of measuring an axial force of the tire during the running step; and an evaluation step of determining an axial force when the tire goes over the protrusion provided on the plane at an evaluation speed based on the measured axial force, The rolling speed is smaller than the evaluation speed. Method for evaluating tire vibration characteristics.

4. A method for evaluating vibration characteristics of a tire, comprising: The axial force when the tire goes over a protrusion provided on a flat surface is calculated from the axial force when the tire goes over a protrusion provided on the running surface of a running drum, A preparation process of setting a tire model that reproduces the tire and a drum model that reproduces the traveling drum using a computer; a setting step of setting a rolling speed when the tire model runs on the drum model; a running step of running the tire model on the drum model at the set rolling speed; a measuring step of calculating an axial force of the tire model during the running step; and an evaluation step of determining an axial force when the tire goes over the protrusion provided on the plane at an evaluation speed based on the calculated axial force, The rolling speed is smaller than the evaluation speed. Method for evaluating tire vibration characteristics.

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