KR20220039199A - Real-time tire running-test device and its testing methods - Google Patents

Abstract

Disclosed are a real-time tire running test device and a test method thereof. According to the present invention, the real-time tire running test device comprises: a test drum rotating a tire; a spindle fixing the tire to rotate the tire on a test device; a carrier moving the spindle with the tire mounted thereon to the test drum to maintain the tire while applying a pressure to the tire; and a microphone collecting a friction sound generated by the tire. The real-time tire running test device further comprises a control unit determining defect status in real time based on the frequency, wavelength, and amplitude of the friction sound acquired through the microphone. Accordingly, a vulnerable portion of a tire with weak durability performance can be identified to remedy the corresponding portion to effectively increase the durability performance of the tire. When an accident occurs, a safety accident involving a worker performing work in the vicinity by fragments can be prevented. A collision between a drum and a rim can be prevented to reduce maintenance and management costs of the test device. Defect occurrence time can be consistently maintained to reduce durability performance differences by test deviations.

Description

Real-time tire running-test device and its testing methods

The present invention relates to a real-time tire driving test apparatus and a test method therefor, and more particularly, it is possible to detect a defect at an early stage by measuring a noise signal during a tire endurance performance test, so that the test can be stopped in advance before an accident occurs. It relates to a real-time tire driving test apparatus and its test method.

In general, a tire driving test is for measuring performance such as a change in physical properties of a tire according to a change in driving speed and load of a vehicle.

In addition, the speed applied to the tire can be controlled by the output of the motor that rotates the drum, and the load applied to the tire is controlled using a servomotor when the carriage approaches the drum.

The overall test is made by combining the speed of the tire and the time that the load is applied, which is handled by a PLC (Programmable Logic Controller). By connecting the thread with the limit device at the end of the thread, the limit device operates when the thread is broken due to tire fragments due to an accident, and the PLC removes the load from the carriage and controls the drum to stop. will do

However, in the case of these tests, it is difficult to set up the same and reproducible test setup because the location for connecting the threads is slightly different for each operator and the tension of the threads is different. The accident could not be detected until it expanded and burst.

When such a tire burst occurs, debris can fly and cause great damage to people working nearby. Fires can also occur because the tires rotate at high speed.

In order to solve this problem, a 'tire abnormality detection device (Korean Patent Registration No. 1494102)' that detects an accident of a tire by measuring the noise of a tire has been proposed in the prior art.

However, this prior art detects an accident by the magnitude of sound pressure, and it is impossible to properly determine the accident time when external noise occurs, and it is difficult to detect the accident time based on a certain standard for each tire, and also detects defects using vibration signals However, since the accelerometer is attached to the spindle shaft and measures the vibration signal, fragments from the high-speed tire wrap around the sensor cable, and there is a limit to damaging the sensor.

Korean Patent Registration No. 1494102 Korean Patent Registration No. 152343

Accordingly, the technical problem to be solved by the present invention is a real-time tire driving test apparatus that can detect a defect at an early stage by measuring a noise signal during a tire endurance performance test and stop the test before an accident occurs, and a real-time tire driving test apparatus and the same To provide a test method.

In order to achieve the above-described technical problem, the present invention provides a test drum for rotating a tire, a spindle for fixing the tire so that it can be rotated in a test apparatus, and applying pressure to the tire by moving the spindle on which the tire is mounted to the test drum. A real-time tire driving test apparatus comprising a carrier capable of holding the tire and a microphone for collecting friction noise generated from the tire, the real-time tire driving test apparatus comprising: determining whether a defect exists in real time based on the frequency, wavelength, and amplitude of the friction sound acquired through the microphone; It provides a real-time tire driving test apparatus comprising; a control unit.

According to another embodiment of the present invention, after creating a distribution form by substituting characteristic factors for the frequency, wavelength, and amplitude, it may be determined whether or not the product is good quality based on the non-defective boundary line of the steel phase.

In addition, the present invention provides a step (S1) of preparing a database including normal data and defect data through a driving test of multiple tires, and obtaining normal data immediately after the speed of the test target tire increases and comparison data after a certain period of time (S2), selecting a characteristic factor to be applied to the normal data and the comparison data through a Z-score (S3), and substituting the normal data and the comparison data into the selected characteristic factor It provides a real-time tire driving test method comprising the steps of presenting a distribution form (S4) and determining whether or not the tire running test is successful by creating a non-defective boundary line on the distribution form (S5).

According to another embodiment of the present invention, the jet score may be to select a characteristic factor based on whether the normal data and comparison data groups of the database are far from each other and the data of each group are close to each other.

According to another embodiment of the present invention, the non-defective boundary line may be set through a vector operator.

Advantageous Effects of Invention According to the present invention, it is possible to identify a vulnerable part of a tire having a weak durability, and thereby improve the tire durability performance effectively by supplementing the part.

In addition, when an accident occurs, it is possible to prevent safety accidents that may occur to workers working in the vicinity due to debris, and it is possible to prevent the collision between the drum and the rim, thereby reducing the maintenance cost of the test equipment.

In addition, it is possible to consistently maintain the time of occurrence of defects, thereby exhibiting the effect of reducing the difference in durability performance due to test deviation.

1 is a diagram schematically showing the configuration of a testing apparatus according to the present invention,
Figure 2 is a diagram schematically showing the role of the system controlled by the control unit of Figure 1,
3 is a graph showing tire friction noise generated during a test according to the present invention in analog form;
4 is a graph showing a distribution form as a result of substituting the amplitude of tire friction noise according to the present invention to two characteristic factors, and displayed in the xy coordinate system, and showing good or bad (normal and defective) based on the non-defective boundary line, which is an imaginary line;
5 is a table showing examples of various equations of characteristic factors according to the present invention.

Hereinafter, it should be noted that the technical terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention, and the technical terms used in the present invention have a different meaning in particular in the present invention. Unless defined, it should be interpreted in the meaning generally understood by those of ordinary skill in the art to which the present invention pertains, and should not be interpreted in an overly comprehensive meaning or in an excessively reduced meaning.

In addition, when the technical term used in the present invention is an incorrect technical term that does not accurately express the spirit of the present invention, it should be understood by being replaced with a technical term that can be correctly understood by those skilled in the art. In addition, the general terms used in the present invention should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted in an excessively reduced meaning.

In addition, the singular expression used in the present invention includes a plural expression unless the context clearly indicates otherwise. It should not be construed as necessarily including all of several steps, and it should be construed that some components or some steps may not be included, or additional components or steps may be further included.

1 is a diagram schematically showing the configuration of a testing apparatus according to the present invention, FIG. 2 is a diagram schematically illustrating the role of the system controlled by the control unit of FIG. 1, and FIG. 3 is a diagram that occurs during testing according to the present invention It is a graph showing the tire friction noise as it is in analog form, and FIG. 4 is a result of substituting the amplitude of tire friction noise according to the present invention into two characteristic factors to create a distribution form and display it in the xy coordinate system, based on the non-defective line, which is an imaginary line It is a graph showing good and bad (normal and defective) as , and FIG. 5 is a table showing examples of various equations of characteristic factors according to the present invention, which will be described with reference to this.

The real-time tire driving test apparatus 100 according to the present invention includes a test drum 300 for rotating a tire 200, a spindle 400 for fixing the tire so that it can rotate in the test apparatus, and a spindle on which the tire is mounted. Real-time tire driving comprising a carrier 500 capable of moving to a test drum and maintaining the tire while applying pressure, a microphone 600 collecting a friction sound generated from the tire, and a control unit determining whether a defect is based on the friction sound In the test apparatus, it is characterized in that the defect is determined in real time based on the frequency, wavelength, and amplitude of the fricative sound acquired through the microphone (600).

The microphone 600 is disposed vertically above or below the portion where the tire and the test drum come into contact, measures the noise of the friction-rotating tire, and transmits a noise signal to the control unit, and the control unit includes a sound processing engine (DAQ), a computer, It performs the role and function of converting the noise measured in analog, including PLC, into digital and storing it as data.

In addition, the digital data of the noise acquired by the control unit as friction noise is information about the frequency, amplitude, and wavelength of the sound, and these data are basic data for judging a normal or defective state in real time through signal processing by computing, If it is judged as defective, the test equipment can be stopped, and although it is not specifically limited, the ECE-R30 High Speed test method can be used.

The control unit creates a distribution form by substituting characteristic factors for the frequency, wavelength, and amplitude of friction noise, and then determines whether the product is good or not based on the quality boundary line of the steel phase. .

The real-time tire driving test method according to the present invention includes the steps of preparing a database including normal data and defect comparison data through a driving test of multiple tires (S1), and a jet score of a characteristic factor to be applied to the normal data and the defect data Selecting through (Z-score) (S2), substituting normal data and defect data into the selected characteristic factors to present a non-defective boundary line in the distribution form (S3) and the test tire measured during real-time driving The data is characterized in that it includes a step (S4) of determining whether the tire is satisfactory or not based on the non-defective boundary line.

First, step S1 is a process of preparing a database including normal data and defect data through a driving test of multiple tires. The drum rotates in contact with the tire at a predetermined speed and load, causing damage, pressure drop, and puncture. Data acquired for a certain period of time after the tire has reached the appropriate temperature and the temperature warmed during driving (immediately after warming up) is classified as normal data, and data acquired for a certain period of time before the tire becomes defective is classified as defect data.

These data refer to data obtained by converting an analog sound generated by a tire that rotates while rubbing into a digital signal through the microphone.

For example, after warming up, the sound generated by the rotating tire at 1 minute intervals is measured for 10 minutes, the amplitude according to the time is acquired, and the amplitude is stored as normal data, and the time flows at 1 minute intervals for 10 minutes from 20 minutes before the accident. Acquires amplitudes according to , and stores them as defect data, and prepares a database that collects data on multiple tires.

Next, step S2 is a step of selecting a characteristic factor to be applied to the normal data and the defect data through a Z-score. As can be seen in the table of FIG. 5, the characteristic factor is the population average, variance, As a value expressed by various equations such as frequency, signal to noise ratio (SNR), and root mean square (RMS), it is important to determine which characteristic factor to use. Based on the variance value, the larger the difference in the mean value and the smaller the variance value, the more advantageous characteristic factors are judged.

In other words, the jet score selects an equation as a characteristic factor by which the normal data and defective data groups in the database are far from each other (the difference in average value is large), and the data of each group is close to each other (the variance is small).

As an example, such a jet score may be expressed by Equation 1 below.

<Equation 1>

Here, the numerator is the difference between the averages of the characteristic factors, and the denominator is the variance. If the Z-score value is large, it means that the difference in the mean value between the groups is large, the variance of each group is small, and it means that the classification between the two groups is excellent.

: 모집단1의 평균

: mean of population 1

: 모집단2의 평균

: mean of population 2

: 모집단1의 표준편차 (분산의 제곱)

: standard deviation of population 1 (squared of variance)

: 모집단2의 표준편차 (분산의 제곱)

: standard deviation of population 2 (squared of variance)

: 모집단1의 표본수

: number of samples in population 1

: 모집단2의 표본수

: number of samples in population 2

In other words, the characteristic factors are very diverse, and the jet score is used as a method of quantifying how far apart the normal and defective data groups are by selecting N characteristic factors with large jet scores rather than substituting them with a specific algorithm.

The dimension of the distribution of data is determined according to the number of characteristic factors selected. If two characteristic factors are selected, it becomes a line separating the good product boundary in planar coordinates, and if three characteristic factors are selected, it becomes a good product boundary surface in spatial coordinates. .

If N characteristic factors are selected in this way, the quality boundary is divided into N-1 dimensions.

Next, step S3 is a step of determining whether or not the tire driving test is successful by substituting normal data and defect data into the selected characteristic factor to present a distribution form and creating a non-defective boundary line. In order to perform judgment (pass/fail judgment), it is necessary to create a good product boundary line that distinguishes the distributed data. can be set through

The vector operator connects the outermost data of each characteristic factor to create a vector value, and considers the only line in which the distance between each vector of normal and defective data is the maximum as a non-defective line. If two characteristic factors are selected, the outermost data of the two characteristic factors is selected for the normal data and the defective data in planar coordinates, and this is calculated as a vector value. . If three characteristic factors are selected, the outermost data becomes three and becomes a plane vector.

In step S4, the data measured in real time during the tire driving test is a step to determine whether a defect is normal or defective based on the above-mentioned non-defective boundary line.

Driving test device 100, tire 200,
test drum 300, spindle 400,
Carrier 500, microphone 600.

Claims (5)

A test drum for rotating the tire, a spindle for fixing the tire so that it can rotate in the test device, a carrier for maintaining the tire while applying pressure by moving the spindle on which the tire is mounted to the test drum; A real-time tire driving test apparatus including a microphone for collecting friction sounds,
and a control unit that determines whether there is a defect in real time based on the amplitude of the friction sound acquired through the microphone.
The method of claim 1,
A real-time tire driving test apparatus, characterized in that after creating a distribution form by substituting the characteristic factor into the amplitude, it is determined whether the product is good or not based on the non-defective boundary line of the steel phase.
preparing a database including normal data and defect data through a driving test of multiple tires (S1);
acquiring normal data immediately after the speed of the test target tire increases and comparison data after a predetermined time (S2);
selecting a characteristic factor to be applied to the normal data and the comparison data through a Z-score (S3);
presenting a distribution form by substituting normal data and comparative data into the selected characteristic factors (S4); and
A real-time tire driving test method comprising: a step (S5) of determining whether or not the tire driving test is successful by creating a non-defective boundary line in the distribution form.
4. The method of claim 3,
The jet score is a real-time tire driving test method, characterized in that the characteristic factor is selected based on whether the normal data of the database and the comparison data group are far from each other and the data of each group are close to each other.
4. The method of claim 3,
The real-time tire driving test method, characterized in that the non-defective boundary line is set through a vector calculator.

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