JP4360455B2 - Method for measuring tire cornering characteristics - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring the cornering characteristics of a tire, and more particularly, tire cornering suitable for measuring arbitrary cornering data as a dependent variable while rotating the tire in a running pattern in which condition variables are continuously changed. The present invention relates to a characteristic measurement method.
[0002]
[Prior art]
When measuring tire cornering characteristics in the steady state, the dependent variables (lateral force, cornering force, self-aligning torque, rolling resistance, tread surface temperature) with the steady state variables (slip angle, load, camber angle, slip rate) Etc.) and a method in which the dependent variable is measured by regarding the state where the condition variable is slowly changed as a steady state.
[0003]
In the former case, since the measurement is performed after the tire condition is stabilized, it generally takes time, and the amount of tire wear is remarkably increased. The tread groove depth has a considerable influence on the cornering characteristics. Therefore, when the tire wear amount increases as described above, a change in cornering characteristics due to condition variables and a change in cornering characteristics due to wear are mixed. Therefore, in order to reduce the amount of wear as much as possible, measurement is generally performed at an extremely low speed. Further, when measuring the cornering characteristics, it is necessary to perform preliminary traveling in consideration of the physical properties of rubber that the tire generates heat and changes its hardness. However, such preliminary traveling further causes wear. Therefore, the above measurement form is not preferable as a tire cornering characteristic measurement method.
[0004]
On the other hand, in the latter case, since the measurement is completed in a relatively short time, there is an advantage that even higher loads (large slip angle, high load, large camber angle, high slip rate) are measured than the former measurement method. . As a measurement procedure, a predetermined preliminary traveling is performed, a traveling pattern in which a change in the condition variable is determined is performed for one cycle, and measurement data of the dependent variable is collected during that period.
[0005]
However, this method has the following problems. First, because the change pattern of the condition variable in the determined preliminary travel does not necessarily match the change pattern being measured in the main travel, and the heat generation temperature history is different between the preliminary travel and the main travel, The cornering characteristics are measured while the tire condition is changing without fulfilling the role. For this reason, the reproducibility of the measurement result is deteriorated. Second, since data is generally collected over time, the condition variables become data with unequal intervals and the number of data becomes large. When using measurement data, draw a so-called Lissajous diagram with the conditional variable on the X-axis and the dependent variable on the Y-axis. To compare the data measured under different conditions and the data measured with different tires, the conditional variable Because the number of data and the data interval do not match, all data of the conditional variables and dependent variables must be stored and compared. In addition, it is desirable to remove noise contained in the measurement data. However, since the data is unequal, the method such as filtering cannot be used as it is, and the data is temporarily increased by interpolation etc. The current situation is that data is compressed by thinning out after filtering.
[0006]
In this way, the tire cornering characteristic measurement method that measures the dependent variable with the condition variable slowly changed as a steady state is compared with the case where the dependent variable is measured with the conditional variable set to the steady state. Although advantageous, there is a desire to further improve its usefulness.
[0007]
[Problems to be solved by the invention]
An object of the present invention is a method for measuring any cornering data as the dependent variable while rotating the tire in running pattern of changing the condition variable continuously, allowing the data processing to facilitate and improve their usefulness Another object of the present invention is to provide a method for measuring tire cornering characteristics.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the tire cornering characteristic measuring method of the present invention provides a dependent variable while rotating a tire in a running pattern that continuously changes at least one of a slip angle, a load, a camber angle, and a slip ratio. In the method of measuring arbitrary cornering data relating to tire cornering characteristics, the measured condition variable value is divided into a plurality of sections having an arbitrary section width, and a dependent variable value at a time corresponding to each section is extracted. An average value of the conditional variable and an average value of the dependent variable are calculated for each section, and processing for associating the conditional variable and the dependent variable as cornering characteristics is performed based on these average values .
[0009]
The condition variable values measured in this way are divided into a plurality of sections having an arbitrary section width, and the dependent variable values at the time corresponding to each section are extracted, and the average value of the conditional variables and the dependent variable values for each section are extracted. By calculating average values and using these average values, it is possible to remove noise and compress data without causing waveform distortion. In particular, even when the measured condition variable values are unequal interval data, the data is compressed by a single process without increasing the data, and this is easily converted into equally spaced data. Can do. As a result, with respect to tire cornering characteristics, it is possible to easily compare data measured under different conditions and data measured with different tires. The data compression process can also be performed in real time while collecting data.
[0010]
Further, the tire cornering characteristic measuring method of the present invention for achieving the above object is the method of rotating a tire in a running pattern in which at least one condition variable is continuously changed among a slip angle, a load, a camber angle, and a slip ratio. In the method of measuring arbitrary cornering data related to tire cornering characteristics as a dependent variable, in addition to performing the above-described processing, at least two travel patterns are repeated without performing preliminary travel of a travel pattern different from the test. It is characterized by collecting cornering data at the time of the driving pattern after the first time .
[0011]
In this way, a running pattern that continuously changes an arbitrary condition variable is repeated at least twice, cornering data is collected for the second and subsequent running patterns, and the first running pattern under the same conditions as the measurement is preliminarily run. Therefore, the reproducibility of the measurement result can be improved by approximating the exothermic temperature history in the preliminary traveling and the main traveling.
[0012]
More specifically, the data compression processing is performed by extracting section setting means for dividing the measured condition variable value into a plurality of sections having an arbitrary section width, and extracting a dependent variable value at a time corresponding to each section. Means, computing means for calculating the average value of the condition variable and the average value of the dependent variable for each section, and data processing means for processing the condition variable and the dependent variable in association with each other as cornering characteristics based on the average value. The section setting means divides the measured condition variable value into a plurality of sections having an arbitrary section width, the extraction means extracts a dependent variable value at a time corresponding to each section, and the calculation means The average value of the conditional variable and the average value of the dependent variable are calculated for each section, and the data processing means calculates the conditional variable as a cornering characteristic based on the average value obtained from the calculation means. It is implemented by performing the process of associating a dependent variable.
[0013]
In the present invention, it is possible to improve the usefulness of the tire cornering characteristic measurement method by implementing at least one of the two means described above, but a better result can be obtained by combining these.
[0014]
When data processing is performed with the measured condition variable values divided into a plurality of sections, the section width may be set so that five or more condition variable and dependent variable data are included in the section. More effective data compression is performed by including five or more pieces of data in the section.
[0015]
When a slip angle is selected as the condition variable, the section width of the slip angle is preferably 0.1 to 2.0 °, more preferably 0.1 to 0.5 °.
[0016]
When a load is selected as the condition variable, the section width of the load is preferably 50 to 1000N, more preferably 50 to 500N.
[0017]
When the camber angle is selected as the condition variable, the section width of the camber angle is preferably 0.5 to 2.0 °, more preferably 0.5 to 1.0 °.
[0018]
When the slip ratio is selected as the condition variable, the section width of the slip ratio is preferably 0.2 to 5.0%, more preferably 0.2 to 2.0%.
[0019]
By specifying the interval width of the condition variable as described above, more effective data compression is performed. In other words, since the tire cornering characteristics are non-linear with respect to the condition variables, the characteristics cannot be grasped if the section width is too coarse. On the other hand, if the section width is too small, the effect of noise reduction is reduced and the data compression efficiency is deteriorated.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0021]
In the present invention, using a drum-type testing machine, a belt-type testing machine, etc., while rotating the tire in a running pattern that continuously changes at least one condition variable among slip angle, load, camber angle, and slip rate, Arbitrary cornering data relating to tire cornering characteristics is measured as a dependent variable for the conditional variable. Examples of cornering data include lateral force, cornering force, self-aligning torque, rolling resistance, and tread surface temperature.
[0022]
1 to 3 show measurement data of Example 1 of the present invention. In the first embodiment, the lateral force Fy (N) and the self-aligning torque are used as dependent variables while rotating the tire in a running pattern in which the slip angle SA (°) is continuously changed within a range of ± 13 ° as the conditional variables. Mz (Nm) and tread surface temperature T (° C.) were measured.
[0023]
As shown in FIGS. 1 to 3, at least two travel patterns for increasing or decreasing the slip angle SA within the measurement range are repeated, and cornering data for the second and subsequent travel patterns is collected. Here, the cycle in which the slip angle SA is decreased from 0 ° to −13 °, increased from −13 ° to + 13 °, and decreased from + 13 ° to 0 ° is defined as a single running pattern, and data in the latter half of the graph is obtained. use. That is, the data of the lateral force Fy, the self-aligning torque Mz, and the tread surface temperature T are slightly different between the first half and the second half of the graph, but the second half data (second time) is the third time (not shown). )) And is stable.
[0024]
Based on the above results, plotting the slip angle SA, which is a conditional variable, on the X-axis and the lateral force Fy, which is the dependent variable, and the self-aligning torque Mz, on the Y-axis, shows the processing data associating the conditional variable with the dependent variable. 4 is obtained. FIG. 4 includes a total of 2750 data collected at a frequency of 25 data per 0.5 ° slip angle for each dependent variable. As it is, the number of data is large, and it is difficult to store and compare data. Therefore, as shown in FIG. 5, the data is compressed with a slip angle of 0.5 ° step for each dependent variable to obtain a total of 53 data, thereby facilitating data storage and comparison.
[0025]
The data compression process divides the measured condition variable value (slip angle SA) into a plurality of sections having arbitrary section widths, and time dependent variables (lateral force Fy, self-aligning torque) corresponding to each section. Mz) is extracted, the average value of the conditional variable and the average value of the dependent variable are calculated for each section, and these average values may be plotted as described above.
[0026]
For example, as shown in FIG. 6, a section having a section width of 0.5 ° is set as the slip angle SA, and the lateral force Fy at the time corresponding to the section is extracted. Then, the average value of the data in the frame indicated by the broken line is calculated for the slip angle SA, the average value of the data in the frame indicated by the solid line is calculated for the lateral force Fy, and both average values are stored as data corresponding to each other. Just do it. Similarly for the self-aligning torque Mz, as shown in FIG. 7, a section having a section width of 0.5 ° is set in the slip angle SA, and the self-aligning torque Mz at the time corresponding to the section is extracted. For the slip angle SA, the average value of the data in the frame indicated by the broken line is calculated, for the self-aligning torque Mz, the average value of the data in the frame indicated by the solid line is calculated, and both average values are data corresponding to each other. Save as.
[0027]
8 to 10 show measurement data of Example 2 of the present invention. In Example 2, the rolling resistance Fx (N) and the lateral force Fy () are used as dependent variables while rotating the tire in a running pattern in which the slip ratio SR (%) is continuously changed within a range of ± 35% as the conditional variables. N), the tread surface temperature T (° C.) was measured.
[0028]
As shown in FIGS. 8 to 10, at least two travel patterns for increasing or decreasing the slip ratio SR within the measurement range are repeated, and cornering data for the second and subsequent travel patterns is collected. Here, the cycle in which the slip rate SR is decreased from 0% to -35%, increased from -35% to + 35%, and decreased from + 35% to 0% is defined as one run pattern, and the data in the latter half of the graph is use. That is, the data of the rolling resistance Fx, the lateral force Fy, and the tread surface temperature T are slightly different between the first half and the second half of the graph, but the second half data (second time) is the third time and later (not shown). Is in good agreement and stable.
[0029]
Based on the above results, when the slip ratio SR, which is a conditional variable, is plotted on the X axis, and the rolling resistance Fx, which is the dependent variable, and the lateral force Fy are plotted on the Y axis, FIG. 11 shows processing data associating the conditional variable with the dependent variable. can get. FIG. 11 includes a total of 1400 data collected at a frequency of 10 data per 1% slip rate for each dependent variable. As it is, the number of data is large, and it is difficult to store and compare data. In addition, since the condition variable is data at unequal intervals, it is difficult to remove noise by filtering. Therefore, as shown in FIG. 12, the data is compressed at a slip rate of 1% step for each dependent variable to obtain a total of 61 data, thereby facilitating data storage and comparison. Further, noise can be easily removed even if the condition variable is data of unequal intervals.
[0030]
In the data compression process, the measured condition variable value (slip rate SR) is divided into a plurality of sections having an arbitrary section width, and time dependent variables (rolling resistance Fx, lateral force Fy) corresponding to each section. Is extracted, the average value of the conditional variable and the average value of the dependent variable are calculated for each section, and these average values may be plotted as described above.
[0031]
In each of the above-described embodiments, data collection and data compression processing are described as independent processes in order to facilitate understanding of the present invention. However, data compression processing can be performed simultaneously with data collection.
[0032]
【The invention's effect】
As described above, according to the present invention, the tire cornering characteristics can be arbitrarily set as a dependent variable while rotating the tire in a running pattern that continuously changes at least one of the slip angle, load, camber angle, and slip ratio. In the method of measuring the cornering data, the following effects can be obtained and the usefulness thereof can be enhanced.
[0033]
(1) Since at least two traveling patterns are repeated and cornering data for the second and subsequent traveling patterns is collected, the reproducibility of measurement results that differ according to the test procedure in the past is improved.
[0034]
(2) Since the dependent variable observed in synchronization with the condition variable is averaged, noise is removed without causing waveform distortion, and various data quantities are calculated with high accuracy.
[0035]
(3) Since equidistant data can be obtained with respect to the condition variable, it is possible to easily compare data measured under different conditions and data measured with different tires, and data can be easily stored.
[Brief description of the drawings]
FIG. 1 is a graph showing slip angle and lateral force data with respect to time as measurement data of Example 1 of the present invention.
FIG. 2 is a graph showing slip angle and self-aligning torque data with respect to time as measurement data of Example 1 of the present invention.
FIG. 3 is a graph showing slip angle and temperature data with respect to time as measurement data of Example 1 of the present invention.
FIG. 4 is a graph showing data of a lateral force and a self-aligning torque with respect to a slip angle as measurement data of Example 1 of the present invention.
FIG. 5 is a graph showing compression data of lateral force and self-aligning torque against slip angle as measurement data of Example 1 of the present invention.
FIG. 6 is a graph showing slip angle and lateral force data with respect to time for explaining a data compression method in the present invention.
FIG. 7 is a graph showing slip angle and self-aligning torque data with respect to time for explaining a data compression method according to the present invention.
FIG. 8 is a graph showing slip ratio and rolling resistance data with respect to time as measurement data of Example 2 of the present invention.
FIG. 9 is a graph showing slip ratio and lateral force data with respect to time as measurement data of Example 2 of the present invention.
FIG. 10 is a graph showing slip ratio and temperature data with respect to time as measurement data of Example 2 of the present invention.
FIG. 11 is a graph showing rolling resistance and lateral force data with respect to a slip ratio as measurement data of Example 2 of the present invention.
FIG. 12 is a graph showing compression data of rolling resistance and lateral force with respect to slip ratio as measurement data of Example 2 of the present invention.
[Explanation of symbols]
SA Slip angle SR Slip ratio Fx Rolling resistance Fy Lateral force Mz Self-aligning torque T Temperature

Claims (7)

  Measured in a method for measuring arbitrary cornering data related to tire cornering characteristics as a dependent variable while rotating the tire in a running pattern in which at least one of the condition variables of slip angle, load, camber angle and slip ratio is continuously changed. The condition variable value is divided into multiple sections with arbitrary section widths, and the dependent variable value at the time corresponding to each section is extracted, and the average value of the conditional variable and the average value of the dependent variable are calculated for each section. And a tire cornering characteristic measuring method for performing a process of associating a conditional variable and a dependent variable as a cornering characteristic based on the average value. The tire cornering characteristic measuring method according to claim 1, wherein cornering data is collected at the time of the second and subsequent traveling patterns by repeating at least two traveling patterns . The tire cornering characteristic measuring method according to claim 1 or 2 , wherein the section width is set so that five or more condition variable and dependent variable data are included in the section. The tire cornering characteristic measuring method according to any one of claims 1 to 3 , wherein a section width of the slip angle as the condition variable is 0.1 to 2.0 °. The tire cornering characteristic measuring method according to any one of claims 1 to 3 , wherein a section width of the load which is the condition variable is 50 to 1000N. The tire cornering characteristic measuring method according to any one of claims 1 to 3 , wherein a section width of the camber angle which is the conditional variable is 0.5 to 2.0 °. The tire cornering characteristic measuring method according to any one of claims 1 to 3 , wherein a section width of the slip ratio as the conditional variable is 0.2 to 5.0%.

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