JP7658182B2 - Method for evaluating tire vibration characteristics - Google Patents

Description

The present invention relates to a method for evaluating the vibration characteristics of a tire.

Conventionally, methods for evaluating the vibration characteristics of tires are known. For example, the following Patent Document 1 proposes a method for evaluating the vibration characteristics of tires from the axial force when the tire goes over a protrusion provided on the running surface of a running drum.

JP 2016-161412 A

However, tests using a running drum like those in Patent Document 1 cannot evaluate the vibration characteristics when the tire goes over a protrusion on a flat surface that it comes into contact with during actual driving, and can only perform a relative evaluation against a reference tire. In addition, 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.

The present invention was devised in consideration of the above-mentioned circumstances, and its main objective is to provide a method for evaluating the vibration characteristics of a tire that can accurately evaluate the vibration characteristics of a tire when going over a protrusion on a flat surface.

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 on a flat surface is calculated from the axial force when the tire goes over a protrusion on the running surface of a running drum.

The tire vibration characteristic evaluation method of the present invention preferably includes a setting step of setting the 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 the 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 passes over the protrusion provided on the flat surface at an evaluation speed.

In the tire vibration characteristic evaluation method of the present invention, the setting step preferably 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 is in contact with 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 is in contact with 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 to the second contact length L2.

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 the product of the evaluation speed and the ratio (L2/L1).

The tire vibration characteristic evaluation method of the present invention preferably includes a preparation step of setting, using a computer, a tire model that reproduces the tire and a drum model that reproduces the running drum, a setting step of setting the 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 measurement step of calculating the axial force of the tire model during the running step, and an evaluation step of determining, based on the calculated axial force, the axial force when the tire goes over the protrusion provided on the plane at an evaluation speed.

In the tire vibration characteristic evaluation method of the present invention, it is desirable that the rolling speed is smaller than the evaluation speed.

The tire vibration characteristic evaluation method of the present invention determines the axial force when the tire goes over a protrusion on a flat surface from the axial force when the tire goes over a protrusion on the running surface of a running drum. This tire vibration characteristic evaluation method determines the axial force when the tire goes over a protrusion on a flat surface based on the axial force when the tire goes over a protrusion on a running drum, which is highly reproducible, and therefore can accurately evaluate the vibration characteristics of the tire.

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. FIG. 2 is a schematic diagram showing the tire of FIG. 1 climbing over a protrusion provided on the running surface of a running drum. 1 is a flowchart of a method for evaluating vibration characteristics of a tire. 13 is a flowchart of a setting process. FIG. 4 is a schematic diagram showing the ground contact surface in the first step. 11 is a schematic diagram showing the ground contact surface in the second step. FIG. 13 is a graph showing an example of a result of a road reaction force in a comparative example. 13 is a graph showing an example of the results of axial vertical forces in a comparative example. 13 is a graph showing an example of a result of a longitudinal force of an axis in a comparative example. 13 is a graph showing an example of a result of a road reaction force in the embodiment. 13 is a graph showing an example of the results of the vertical axial force in the embodiment. 13 is a graph showing an example of the results of the vertical axial force in the embodiment.

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 car. The tire 1 is not limited to a pneumatic tire for a passenger car, and can be used for various tires such as a pneumatic tire for a heavy load, a pneumatic tire for a motorcycle, and an airless tire that is not filled with pressurized air inside.

As shown in Figures 1 and 2, the method for evaluating the vibration characteristics of tire 1 in this embodiment involves determining the axial force F1 when tire 1 passes over protrusion 3 on flat surface 2 from the axial force F2 when tire 1 passes over protrusion 5 on running surface 4a of running drum 4.

This method of evaluating the vibration characteristics of a tire 1 determines the axial force F1 when the tire 1 goes over a protrusion 3 on a flat surface 2 based on the axial force F2 when the tire goes over a protrusion 5 on a traveling drum 4, which has high reproducibility, so the vibration characteristics of the tire 1 can be evaluated with high accuracy.

In a more preferred embodiment, the protrusions 3 on the plane 2 are 2 to 20 mm high and have a square cross section. It is desirable that the protrusions 5 on the running surface 4a of the traveling drum 4 have the same cross-sectional shape as the protrusions 3 on the plane 2. Such protrusions 5 on the traveling drum 4 are useful for accurately evaluating the vibration characteristics of the tire 1 when it goes over the protrusions 3 on the plane 2.

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

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

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, a "standard rim" for JATMA, a "design rim" for TRA, and a "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.

"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 the "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.

In the method for evaluating the vibration characteristics of a tire 1 according to this embodiment, after the preparation step S1, a setting step S2 is performed in which the 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 when evaluating at a load different from the normal load may be set.

Here, "normal load" refers to the load determined for each tire by each standard in the standard system including the standard on which 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. "Normal load" refers to the load determined for each tire by the manufacturer, etc., when there is no standard system including the standard on which tire 1 is based.

Figure 4 is a flowchart of the setting step S2. As shown in Figure 4, the setting step S2 of this embodiment includes a first step S21 of determining a first contact length L1 (shown in Figure 5), which is the contact length in the tire circumferential direction when the tire 1 in a normal state comes into contact with a plane 2 under a normal load.

Figure 5 is a schematic diagram showing the contact surface 1a in the first step S21. As shown in Figure 5, the first step S21 involves, for example, determining the first contact length L1 by grounding the tire 1 on a sheet-like pressure sensor provided on a flat surface. The first step S21 may also determine the first contact length L1 by grounding the tire 1 on a transparent flat plate, or may determine the first contact length L1 by a computer-based simulation.

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.

Figure 6 is a schematic diagram showing the contact surface 1b in the second step S22. As shown in Figure 6, the second step S22 involves, for example, determining the second contact length L2 by placing the tire 1 on a sheet-shaped pressure sensor that is provided on a curved surface with the same curvature as the traveling drum 4. The second step S22 may, for example, determine the second contact length L2 by placing the tire 1 on a transparent curved plate, or may determine the second contact length L2 by a computer-based simulation.

As shown in Figures 4 to 6, the setting step S2 of this embodiment includes a first step S21 and a second step S22, followed by a third step S23 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 to the second contact length L2. This 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.

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 of 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.

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 this manner, the third step S23 can set the rolling speed V2 with a simple calculation, and can easily perform a highly accurate evaluation.

As shown in Figure 3, the method for evaluating the vibration characteristics of a tire 1 in this embodiment includes a running step S3 in which the tire 1 runs 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.

The vibration characteristic evaluation method for tire 1 of this embodiment includes an evaluation step S5 for determining the axial force F1 when tire 1 passes over protrusion 3 provided on flat surface 2 at evaluation speed V1 based on the measured axial force F2. 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 a highly accurate evaluation of the vibration characteristics of tire 1.

In another embodiment, the vibration characteristic evaluation method for a tire 1 is evaluated by a computer-based simulation. 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 up using a computer. It is preferable that the drum model includes a protrusion model that reproduces the protrusion 5. This type of vibration characteristic evaluation method for 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.

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

In another embodiment, the running process S3 runs the tire model on a drum model at a set rolling speed V2. In another embodiment, the measurement process S4 calculates the axial force F2 of the tire model in the running process S3. In such a running process S3 and measurement process S4, the calculation load of the axial force F2 when going over the protrusion model provided on the drum model is small, so that it is possible to perform calculations that take into account the effects of multiple disturbances, and to accurately evaluate the vibration characteristics of the tire 1.

In another embodiment, the evaluation step S5 determines the axial force F1 when the tire 1 passes over a protrusion 3 provided on a plane 2 at an evaluation speed V1 based on the calculated axial force F2. This method of evaluating the vibration characteristics of a tire 1 can easily obtain a highly accurate evaluation of the vibration characteristics of the tire 1.

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

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 the 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.

<Common specifications>
Tire size: 205/60R16
Rim size: 16x6J
Air pressure: 220kPa
Load: 4.5 kN
Estimated speed: 40km/h
Protrusion height: 5mm
Projection cross-sectional shape: Square

<Tests for Comparative Examples>
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 an evaluation speed of 40 km/h. The axial forces were measured as vertical axle force and longitudinal axle force. The test results of the comparative example are shown as symbol A in Figures 7 to 9. Figure 7 is a graph showing an example of the results of the vertical road reaction forces of the comparative example, Figure 8 is a graph showing an example of the results of the vertical axle force of the comparative example, and Figure 9 is a graph showing an example of the results of the longitudinal axle force of the comparative example. The horizontal axes of Figures 7 to 9 each represent time.

Example Tests
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 traveling 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.

The upper and lower road reaction forces and 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 force was measured as both the vertical and longitudinal axle forces. The test results of the embodiment are shown as B in Figures 10 to 12. Figure 10 is a graph showing an example of the results of the upper and lower road reaction forces of the embodiment, Figure 11 is a graph showing an example of the results of the vertical and longitudinal axle forces of the embodiment, and Figure 12 is a graph showing an example of the results of the longitudinal axle forces of the embodiment. The horizontal axes of Figures 10 to 12 each represent time.

<Evaluation Criteria Test>
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 standard test are shown as C in Figures 7 to 12.

The test results confirmed that the waveforms of the road reaction force and axial force of the example were equivalent to the evaluation criteria, and compared to the comparative example, it was possible to accurately evaluate the vibration characteristics of the tire when going over a protrusion on a flat surface.

1 Tire 2 Flat surface 3 Protrusion 4 Traveling drum 4a Traveling surface 5 Protrusion

Claims (4)

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. 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). 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 rolling speed is smaller than the evaluation speed.
Method for evaluating tire vibration characteristics. 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 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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