JP2002055026A - Method and equipment for measuring high-speed uniformity of tire and method for sorting tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an equipment for predicting high-speed uniformity of a tire accurately in a short time, and to provide a method for sorting tires based on its prediction value. SOLUTION: In the method for measuring the high-speed uniformity of a tire, measurement data of high-speed uniformity is recorded any time, according to the traveling time and curve fitted to an operation formula converging to a constant value, and the converged value is estimated as the high-speed uniformity or that tire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring method for predicting an estimated value of a high-speed uniformity of a tire, a measuring apparatus therefor, and a high-speed uniformity sorting method for a tire.

[0002]

2. Description of the Related Art The measurement of the uniformity (uniformity) of a tire, which is one of the exciting forces applied to the vibrations of a vehicle such as an automobile, is performed by using a well-known uniformity machine defined in JASO (Japan Automobile Engineering Association) C607. Tire is 60R
It measures low-speed uniformity when rotating at a low speed of less than or equal to PM. Fluctuation of force in the radial direction of the tire (radial force variation, RFV) and fluctuation of force in the tire width direction (lateral force variation, LFV)
And the variation of the force in the tire longitudinal direction (tangential force variation, TFV).

When a tire runs in a high speed range where it is actually used, the tire characteristics change as the tire temperature increases, and it takes a long time for the characteristics to stabilize and converge. I have. Therefore, in the high-speed uniformity that measures at the actual speed of the tire, a sufficient warm-up time is required to obtain a highly accurate measurement value.

[0004]

In recent years, there has been a strong demand in the market for improvement of high-speed uniformity due to vibration and noise problems during high-speed running, and there has been an increasing demand to apply high-speed uniformity standards for tires to product standards.

[0005] The high-speed uniformity is inaccurate when measured with insufficient warm-up time, and a tire having a large uniformity is accidentally shipped to the market. Also, when sufficient warm-up time is provided and the accuracy is measured to improve the measurement efficiency, the measurement efficiency decreases and many tires are reduced. Cannot be measured, and a large number of uniformity machines are required for use in product inspection on a normal production line, resulting in a significant increase in cost.

According to the present invention, the convergence value of the tire high-speed uniformity is easily estimated from the data during the measurement of the high-speed uniformity of the tire by calculating the measurement data during the warm-up of the tire. It is an object of the present invention to provide a high-speed uniformity measurement method and a device for a tire, and a method for selecting a tire, which can accurately measure the high-speed uniformity.

[0007]

SUMMARY OF THE INVENTION The present invention has been made as a result of study to solve the above-mentioned problems, and the relationship between the tire warm-up time and the high-speed uniformity is reduced to a constant value over time as shown in FIG. This has been achieved based on the fact that the convergence has been confirmed, and it has been found that the high-speed uniformity is curve-fitted to an arithmetic expression representing asymptotics such that it converges to a certain value.

According to a first aspect of the present invention, in the method for measuring high-speed uniformity of a tire, measurement data of the high-speed uniformity is recorded at any time according to a traveling time, and the measured data is curve-fitted to an arithmetic expression converging to a certain value. And calculating the convergence value as the high-speed uniformity value of the tire.

According to a second aspect of the present invention, in the method for measuring high-speed uniformity of a tire, measurement data of the high-speed uniformity is recorded at any time according to a running time, and the measured data is curve-fitted to an arithmetic expression converging to a certain value. The method according to claim 1, wherein a value is calculated for each traveling time, and when a change in the value of the convergence value becomes a fixed value or less, the convergence value at that time is estimated as a high-speed uniformity value of the tire. This is a method for measuring high-speed uniformity of tires.

According to a third aspect of the present invention, there is provided a tire uniformity measuring device including a data processing device in which a rim-assembled tire is detachably attached to a drum rotating at a high speed. A high-speed uniformity data processing function for a tire according to the tire high-speed uniformity measurement method according to claim 1 or 2, further comprising a linear correlation between the high-speed uniformity value obtained by the data processing and a true high-speed uniformity value. Using the confidence range of the estimate obtained from the relationship, or using the maximum width of data variation obtained from multiple measurement data,
A high-speed tire uniformity measurement device having a data processing function for comparison with a tire high-speed uniformity standard.

According to a fourth aspect of the present invention, there is provided a method for measuring a high-speed uniformity of a tire according to the first or second aspect, or a method for measuring a high-speed uniformity of a tire according to the third aspect, wherein the estimated value of the high-speed uniformity is a true value. Pass / fail the fast uniformity standard value of the tire by using the estimated confidence range obtained from the primary correlation with the fast uniformity value or by using the maximum width of data variation obtained from multiple measurement data. And selecting the tires, and a high-speed uniformity sorting method for the tires.

According to the first to third aspects of the present invention, the convergence value of the high-speed uniformity of the tire can be predicted by using an arithmetic expression to estimate the high-speed uniformity, and the predicted value is determined and the timing to end the measurement is determined. Therefore, high-speed uniformity can be measured in a short time, and measurement of a large number of tires can be performed.

[0013] According to the invention of claim 4, according to claims 1 to 3,
The high-speed uniformity of the tire estimated according to the invention is compared with the standard value of the high-speed uniformity of the tire, and a pass / fail judgment is made. In addition, it is apparent that the measurement of a tire having a value equal to or less than the standard value or a value equal to or greater than the standard value can be completed in a shorter time, and the working efficiency is further improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to an example of a high-speed uniformity RFV primary component (hereinafter abbreviated as high-speed RFV).

FIG. 1 is a schematic view of a high-speed tire uniformity measuring apparatus 10 according to the present invention. A rim-assembled tire 1 is mounted on a tire rotating shaft 3 having a load cell 2. The tire 1 is rotated by a driving motor 7 disposed on a drum shaft 6 at a predetermined rotational speed.
Above, it is attached to the support frame 4 so as to be able to freely contact and separate. Tire 1
, A predetermined load is applied to the tire, the axis of the tire and the axis of the drum are fixed at a fixed distance, and a change in force due to the rotation of the tire is detected by the load cell 2.

The detected value is processed by the data processing device 9 into a load variation waveform for one rotation of the tire to determine each force variation of the tire. This processing device includes a computer having storage means, arithmetic means, and the like, and corrects an unbalance component due to a tire assembly or a rim to obtain a true force variation.

In the above-mentioned high-speed RFV, data is recorded at any time from the start of traveling, and if three or more points of data can be recorded, the data is curve-fitted to an asymptotic expression such that the data converges to a certain value. The data is sent to a data processing device provided in the device, and the high-speed RFV convergence value at that time is calculated by the processing device.

The arithmetic expression indicating the convergence is, for example, the following expression 1 when the data tends to decrease and converge, and the following expression 2 when the data tends to increase and converge: Can be applied.

Y = A · e− ^{t / τ} + B (Equation 1) Y = A · (1- ^{et / τ} ) + B (Equation 2) Here, Y is the convergence of the high-speed RFV. Predicted value, t is measurement time,
τ is a time constant, and A and B are coefficients.

When the data is curve-fitted to the above equation (1) or (2), it converges to a certain value over time as illustrated in FIG. 2 or FIG. Converges to A + B.

Selection of the above formulas 1 and 2 is determined by comparing the sizes of the first data and the second data or the latest data.

In addition to the above two formulas, any formula that can indicate the direction of convergence as shown in the following formula 3 can be used.

Y = A · t ^B (Equation 3) FIGS. 4 and 5 show examples in which the measured data is specifically applied to the above-described equation 1 or 2 to calculate.

FIG. 4 shows high-speed RFV measurement data 119, 127, 133, and 13 when running for 1, 3, 6, 9, and 11 minutes.
The calculation formula of the convergence prediction value is obtained from the five data points having an increasing tendency of 9,141N according to the formula 2, and the formula Y = 3
0.0 · (1−et− ^5.66 ) +114,
The convergence value was 144N, and the correlation coefficient was R = 0.999.

FIG. 5 shows a calculation formula of a convergence prediction value obtained from eight points of high-speed RFV measurement data in the case of a decreasing tendency in accordance with Expression 1 in the same manner as described above, and Expression Y = 32.6 · e.
^{-T / 8 . 45} + 22, the convergence value was 22N, and the correlation coefficient was R = 0.999.

As described above, by selecting the convergence equation according to the tendency of the measured data to increase or decrease, the high-speed RF
V can be curve-fitted to the equation with a high correlation to predict the convergence value, and it can be seen that V is effective for predicting the high-speed RFV convergence value in a short time.

The convergence value is determined by: (1) calculating the convergence value in order from the measurement data for each traveling time within the traveling time until the convergence value based on the actually measured value is expected to be obtained; A method of determining when the change of the operation value becomes equal to or less than a certain value, (2) a high-speed R up to a predetermined time.
It is determined by a method of obtaining an estimated value by curve fitting the FV measurement data to an arithmetic expression.

The fixed value and the designated time in the above case are determined in consideration of an error with respect to a standard value or the like at the time of shipping, and the standard can be determined according to use conditions such as product specifications and destinations. .

Next, a description will be given of the determination of the pass / fail of the high-speed RFV in the tire selection and the termination of the measurement accompanying the determination.

In the tire selection, a convergence value using data obtained by taking a sufficient warm-up time (for example, a 30-minute running-in operation) is taken as a true value in consideration of the reliability range of the estimation, and the convergence value in the warm-up time before that is used. It is obtained from a first-order correlation with a convergence value using data. For example, when a correlation analysis is performed between a predicted convergence value (X) at a warm-up time of 10 minutes and a predicted convergence value (Y) at a warm-up time of 30 minutes, a primary correlation such as Y = a · X is obtained. Calculated from the 90% confidence margin.

(Embodiment) Table 1 shows the magnitude of the primary component of the high-speed RFV, which is a predicted value of the high-speed RFV calculated from a plurality of data of the running (warming time) of 15 minutes. Fast R after 15 minutes and final convergence value
The FV actual measurement values are shown.

Here, the measurement conditions are as follows.

Tire size: 175 / 70R14 84H Rim size: 14 × 5-J Air pressure: 196 kPa Load: 3727 N Speed: 140 km / h

[Table 1] Example 1 shows that the high-speed RFV tends to increase with the running time, and the high-speed RFV predicted value calculated by applying the running data for 15 minutes to Equation 2 is 65N with respect to the final convergence value of 64N. In Example 2, the high-speed RFV tended to decrease with the running time, and the predicted high-speed RFV value calculated by applying the running data for 15 minutes to Equation 1 was 22N with respect to the final convergence value of 22N.

Table 2 shows the results of the high-speed RFV measurement at each running time and the predicted values at that time in the second embodiment. The determination of the high-speed RFV predicted value and the end of the measurement will be described.

[0035]

[Table 2] If you decide on the data up to the travel time specified in advance,
If the designated time is 15 minutes, the high-speed RFV predicted value is 22N.

If the prediction value is determined when the change in the high-speed RFV prediction value becomes equal to or less than the specified value, if the measurement is to be terminated when the change becomes 5 N or less, the data change From the tendency, the previous predicted value is 28N with respect to the predicted value 22N for 15 minutes of traveling, and the difference is 6N, so that it is necessary to continue the measurement. In 20 minutes of traveling, the predicted value is 22N, and the difference from the previous predicted value 22N is 0N, the measurement is completed, and the predicted value of the high-speed RFV can be determined to be 22N.

As described above, according to this method, the convergence value can be determined in a shorter time than originally required, and the measurement can be completed.

Next, a description will be given of an embodiment in which the tires are sorted at the time of shipment and the measurement is terminated at that time.

Examples of the method of judging against the standard value in the tire selection are as follows: (1) When the measured data is recorded and the level is determined to be below the standard value, (2)
(3) When it is determined that the value of the curve-fit convergence value is equal to or less than the standard value even when considering the error, 4) When the measured data is recorded and the level is determined to exceed the standard value, (5) When the change in the measured data is increasing and it is determined that the standard value is exceeded, (6) Convergence with curve fitting For example, when it is determined that the value exceeds the standard value even when the error is considered.

The confidence range of the estimation is defined as the true value of the convergence value using the measured data of the warm-up time up to 30 minutes, and the primary correlation with the predicted convergence value using the measured data in a shorter time. More required. For example, when a correlation analysis is performed between a convergence predicted value (X) at a warm-up time of 10 minutes and a convergence value (Y) at a warm-up time of 30 minutes, a correlation of Y = 1.032 · X is obtained. Assume that the 90% confidence width is 7N. In consideration of this value, it is determined whether the convergence value is within the standard.

When the measurement data of high-speed uniformity of some tires was obtained, the maximum value of the change in the data was 41N. In consideration of this value, it is determined whether the convergence value is within the standard value.

Here, when the standard value of the high-speed RFV is less than 100 N, the determinations (1) to (6) and the end of the measurement will be described below.

(1) The data measured during the warm-up time is 59
If it is less than N, it is determined that it is less than 100N, which is plus 41N, even if it increases the most, so that the measurement can be ended. For example, there is a case where the measurement data is 55N regardless of the warm-up time.

(2) The measured data is decreasing,
Is obtained, the convergence value is determined to be less than 100N, and the measurement can be terminated. For example, the case where the measurement data changes to 110, 102, 96N.

(3) When the predicted convergence value based on the data in the middle of the measurement becomes 93N or less, the confidence range is 7N.
Since the convergence value is determined to be 100 N or less at the risk rate of 5%, the measurement can be ended. For example, the convergence value estimated from the measurement data up to the warm-up time of 10 minutes is 93
N.

(4) The data measured during the warm-up time is 14
If it is 2N or more, minus 41 even if it decreases the most
Since N is determined to be more than 100N, the measurement can be ended. For example, there is a case where the measurement data is 150 N regardless of the warm-up time.

(5) The measured data is increasing,
Is obtained, the convergence value is determined to be 100 N or more, so that the measurement can be ended. For example, if the measurement data is 80, 91, 97, 102N
And when it changes.

(6) When the predicted value of convergence based on data in the middle of measurement is 108 N or more, the confidence range is 7 N, and it is determined that the convergence value is 100 N or more at a risk rate of 5%. Can be terminated. For example,
Measurement data after 1, 4, 7, 10 minutes of warm-up time is 13
In the case of 0, 120, 115, and 112N, the estimated convergence value is 109N, and the measurement can be completed.

As described above, according to the present invention, the high-speed RFV
Prediction and tire sorting can be performed efficiently and in a short time, and accordingly, capital investment can be suppressed.

The arithmetic processing of the measurement data of the high-speed RFV, the determination of the convergence value, and the judgment of the selection are performed by the data processing device provided in the high-speed uniformity measuring device at the same time as the measurement, and are computer-processed.
V can be measured and processed in the same manner as high-speed RFV.

[0051]

As described above, according to the present invention, the measurement data of the high-speed uniformity of the tire is recorded at any time according to the running time, and the measured data is curve-fitted to an arithmetic expression converging to a certain value. Calculate and estimate the convergence value as the high-speed uniformity value of the tire, and when the change of the convergence value falls below a certain value, estimate and measure the convergence value at that time as the high-speed uniformity value of the tire. Is a high-speed uniformity measurement method for tires that can be terminated. Further, a processing function is provided in which the rim-assembled tire is detachably mounted on a drum rotating at high speed, predicts the high-speed uniformity, and compares the tire with a standard value of the tire based on the prediction to select a tire. Is a high-speed uniformity measurement device for tires equipped with a data processing device that has a high-speed uniformity measurement, so that each component of the high-speed uniformity can be predicted in a shorter time and more accurately than before, suppressing stagnation on the production line, and producing products with stable quality. It can be supplied to the market and can respond to market requirements.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a uniformity measuring device according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating an arithmetic expression used in the present invention.

FIG. 3 Same as above.

FIG. 4 is a diagram illustrating prediction of a convergence value of a high-speed RFV according to the embodiment of the present invention.

FIG. 5 Same as above.

FIG. 6 is a diagram showing a relationship between a traveling time and a high-speed RFV.

[Explanation of symbols]

 10 High-speed uniformity measuring device 1 Tire 2 Load cell 3 Tire rotation axis 4 Tire support frame 5 Drum 6 Drum rotation axis 7 Driving motor 9 Data processing device

Claims (4)

[Claims] 1. A high-speed uniformity measurement method for a tire, wherein high-speed uniformity measurement data is recorded at any time according to a running time, and the measured data is curve-fitted to an arithmetic expression converging to a certain value to calculate a convergence value thereof.
A method for measuring a high-speed uniformity of a tire, wherein the convergence value is estimated as a high-speed uniformity value of the tire. 2. A high-speed uniformity measurement method for a tire, wherein high-speed uniformity measurement data is recorded at any time according to a traveling time, and the measured data is curve-fitted to an arithmetic expression converging to a certain value, and the convergence value is calculated for each traveling time. When the change in the value of the convergence value becomes equal to or less than a certain value, the convergence value at that time is estimated as the high-speed uniformity value of the tire, and the high-speed uniformity of the tire according to claim 1, Measurement method. 3. A tire uniformity measuring device comprising a data processing device in which a rim-assembled tire is detachably mounted on a drum rotating at a high speed, wherein the data processing device is one of claims 1 and 2. A high-speed uniformity data processing function of the tire according to the high-speed uniformity measurement method for a tire according to item 2 is provided, and the high-speed uniformity value obtained by the data processing is obtained from a linear correlation with a true high-speed uniformity value. A tire high-speed tire characterized by having a data processing function that compares with a high-speed uniformity standard of the tire by using the estimated confidence width or the maximum width of variation of data obtained from a plurality of measurement data. Uniformity measuring device. 4. The high-speed uniformity obtained by the method for measuring high-speed uniformity of a tire according to claim 1 or 2 or the high-speed uniformity obtained by the measuring apparatus for high-speed uniformity of a tire according to claim 3 is a linear high-speed uniformity value with a true high-speed uniformity value. Using the estimated confidence range obtained from the correlation or the maximum width of the variation of the data obtained from the plurality of measurement data, the pass / fail judgment is performed on the high-speed uniformity standard value of the tire and the tire is selected. A high-speed uniformity sorting method for tires.