JP4187098B2 - Tire failure detection method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire failure detection method and apparatus, and more particularly to a tire failure detection method and apparatus that can detect an internal failure of a tire with high accuracy.
[0002]
[Prior art]
In general, in a tire durability test, a contact-type failure detection device is used to detect an internal failure of the tire, and the detection portion is arranged near the surface of a pneumatic tire rotating on a test drum, and is inflated due to an internal failure. A tire failure is detected by contacting the detected tire surface with the detection unit (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-57-93230 [0004]
[Problems to be solved by the invention]
However, in the method of detecting with the contact-type failure detection device described above, if the pneumatic tire is continuously rotated on the test drum for a long time, the tire internal pressure increases due to the temperature rise of the tire, and the pneumatic tire is moved radially outward. When the rotational speed is increased and the rotational speed is increased, the pneumatic tire expands radially outward due to centrifugal force. In the case of a radial tire, when the load load increases, the portion of the pneumatic tire that contacts the test drum Because the part opposite to the bulge swells, it is necessary to separate the detection part from the tire to some extent in order to eliminate the influence. I can't.
[0005]
For this reason, when the tire surface bulging due to an internal failure is a small displacement that is localized and has a small amount of bulging, the tire surface may be destroyed before it comes into contact with the detection unit. If the tire breaks before detecting an internal failure in this way, it is impossible to identify the location where the failure occurred and analyze the growth process of the failure, which hinders the improvement of the tire.
[0006]
An object of the present invention is to provide a tire failure detection method and apparatus capable of detecting an internal failure of a tire with higher accuracy than before.
[0007]
[Means for Solving the Problems]
To achieve the above object tire failure detection method of the present invention is a tire failure detection method for detecting impaired internal late occurred pneumatic tire rotates, a non-contact which is placed to face the pneumatic tire to the rotating more formula temperature sensor, the surface temperature of a pneumatic tire to the rotating repeats the steps of measuring over one round along the tire circumferential direction, is the measurement at each corresponding position on the tire circumference of the tire to the rotating surface temperature of the predetermined amount of change before and after each time interval is calculated, respectively, that the difference between the change amount the calculated determines that the internal mechanical failure has occurred if it becomes more than a predetermined threshold value Features.
[0009]
Also, tire failure detection device of the present invention is a tire failure detection device for detecting a malfunction internal occurred pneumatic tire rotates, a non-contact temperature sensor disposed to face the pneumatic tire to the rotating When, and a processing means for processing the detection signal from the temperature sensor, said processing means is measured repeatedly over one round along the tire circumferential direction of the pneumatic tire to the rotating by the non-contact type temperature sensor from the surface temperature, the amount of change before and after the predetermined time interval of the surface temperature at each corresponding position on the tire circumference of the tire to the rotating was calculated, the difference between the change amount the calculated is It is characterized in that it is determined that an internal failure has occurred when a predetermined threshold value is exceeded.
[0010]
Another tire failure detection device according to the present invention is a tire failure detection method for detecting that an internal failure has occurred in a rotating pneumatic tire, the non-contact temperature sensor installed facing the pneumatic tire, And processing means for processing a detection signal from the temperature sensor, wherein the temperature sensor repeatedly performs a step of measuring the surface temperature of the rotating pneumatic tire over the circumference in the tire circumferential direction, and the processing The temperature change amount is calculated by comparing the surface temperature data before and after the means measured at a predetermined time interval at each corresponding position on the tire circumference, and the difference in the temperature change amount at any position is calculated. It is characterized in that it is determined that an internal failure has occurred when the value becomes equal to or greater than a predetermined threshold.
[0011]
According to the present invention described above, since a non-contact temperature sensor is used and the occurrence of an internal failure is determined using the difference in the amount of change in the tire surface temperature at each time interval, it depends on the bulging of the tire surface. Internal failure can be detected without Therefore, it is possible to detect a tire failure with higher accuracy than before.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
FIG. 1 shows an example in which the tire failure detection method of the present invention is implemented in a tire durability test, where 1 is a test drum, 2 is a pneumatic tire, and 3 is a pneumatic rotating on the test drum 1 by a rotating test drum 1. A non-contact temperature sensor 4 for measuring the surface temperature of the tire 3 is a processing means for processing a detection signal from the non-contact temperature sensor 3, and the tire failure detection apparatus includes the non-contact temperature sensor 3 and the processing means 4. It has.
[0014]
The test drum 1 is installed so as to be rotatable, and the rotation speed can be changed to an arbitrary speed.
[0015]
A pneumatic tire 2 assembled to a wheel 5 and filled with a predetermined air pressure is rotatably supported on a tire support shaft 6 and rotates on the test drum 1 by contacting the outer peripheral surface of the rotating test drum 1. To do. A predetermined load can be applied to the pneumatic tire 2 via the tire support shaft 6.
[0016]
The non-contact type temperature sensor 3 is preferably composed of an infrared image reading thermometer (for example, an infrared imaging device TVS-8100MKll manufactured by Nippon Avionics Co., Ltd.) that detects the infrared ray and measures the surface temperature, The surface temperature of the rotating pneumatic tire 2 by continuously reading is measured over one turn along the tire circumferential direction, and the process is repeatedly performed at predetermined time intervals.
[0017]
This time interval should be set shorter as the conditions of the tire endurance test become more severe, or as the surface temperature level becomes higher. For example, the interval can be about 1 hour immediately after the start of the test, and about 10 seconds immediately after the occurrence of the failure. In the tire durability test, it is preferable that the non-contact temperature sensor 3 be installed facing both shoulder portions of the pneumatic tire 2 diagonally.
[0018]
The processing means 4 calculates surface temperature data from infrared image data taken from the temperature sensor 3 over the entire circumference of the tire. In addition, the surface temperature data measured before and after a predetermined time interval are compared over one lap at each corresponding position on the tire circumference to calculate the temperature change amount, and even one value is predetermined. If it exceeds the threshold value, it is determined that an internal failure has occurred, the rotation of the test drum 1 is stopped via a control means (not shown), and the tire durability test is terminated.
[0019]
A known rotary encoder (not shown) attached to the tire support shaft 6 is used as a means for identifying each corresponding position on the tire circumference, but it is used for a sidewall portion or a rim portion of the rotating tire. You may make it irradiate light to the attached reflective sheet | seat, and may obtain each corresponding position on a tire periphery by making the position which detected the reflected light into a reference position.
[0020]
Hereinafter, the tire failure detection method of the present invention in the tire durability test will be described with reference to the flow of FIG.
[0021]
First, the test drum 1 is rotated and the pneumatic tire 2 is rotated on the test drum 1. When a predetermined endurance test start speed is reached, a plurality of infrared images of the surface of the pneumatic tire 2 are taken continuously over the circumference of the tire by the temperature sensor 3, and the surface temperature of the pneumatic tire 2 is completely adjusted along the tire circumferential direction. Measure over the lap. This process is repeated at a predetermined time interval (step a).
[0022]
The processing means 4 calculates the surface temperature over the entire circumference of the tire based on the input infrared image every time there is an input for the circumference of the tire from the temperature sensor 3. Then, the front and back surface temperature data measured at predetermined time intervals are compared over one lap at each corresponding position on the tire circumference, and the amount of temperature change at each corresponding position is calculated (step b). ). Further, the calculated temperature change amounts are compared, and the difference between the change amounts (the difference between the maximum change amount and the minimum change amount or the difference between adjacent change amounts) is calculated (step b ′). Preferably, the difference in the amount of change is calculated when the calculated amount of each temperature change exceeds a predetermined amount (for example, 5 ° C.).
[0023]
Subsequently, the difference in the temperature change amount obtained is compared with a predetermined threshold set in advance, to be equal to or larger than the predetermined threshold even one of the differences of each temperature change amount (step c), an internal fault It determines with having generate | occur | produced, the rotation of the test drum 1 is stopped via the control means not shown (step d), and a tire durability test is complete | finished. In step c, if the difference in each temperature change amount is smaller than the predetermined threshold value, the surface temperature measurement of the pneumatic tire 2 is continued, so that the process returns to step a and the subsequent steps are repeated.
[0024]
As a result of intensive studies on the internal failure of the tire, the present inventor has focused on the temperature change on the tire surface. The pneumatic tire 2 rotating on the rotating drum 1 heats up with the passage of time, and the temperature gradually rises. When measuring the tire surface temperature distribution, in general, the relatively high temperature is, for example, the groove bottom portion on the tread surface, and the closer the distance between the tire inner surface and the surface, the higher the temperature, High surface temperature. In other words, the higher the surface temperature is, the higher the internal temperature of that part is, but the temperature rises more at other parts than at other parts, and the temperature of the tire surface corresponding to that part changes more than other parts. Was found to be larger.
[0025]
Therefore, the non-contact temperature sensor 3 is used as described above, and the occurrence of an internal failure is determined using the temporal displacement of the tire surface temperature measured at intervals. As a result, an internal failure can be detected regardless of the bulging state of the tire surface, so that it is possible to detect a tire internal failure with higher accuracy than in the past.
[0026]
In addition, it is possible to detect at the initial stage when an internal failure occurs, and by installing the temperature sensor 3 facing the part to be measured, it is not affected by a groove or a kerf provided on the tire surface. Failure at any part of the tire surface can be detected.
[0029]
In the present invention, in the above embodiment, an example in which the tire failure is measured from the tread portion 2A to the sidewall portion 2B of the pneumatic tire 2 is shown. However, the tire failure in the bead portion 2C from the sidewall portion 2B or the bead portion 2C is shown. In the case of measuring, without capturing a plurality of infrared images continuously as described above, a non-contact temperature sensor 3 captures a single infrared image taken from the tire axial direction and uses it. The processing means 4 may be used for processing.
[0030]
The non-contact temperature sensor 3 configured to capture an infrared image requires a large amount of memory or the like for image processing in the processing unit 4, and therefore the process of measuring the surface temperature of the pneumatic tire as described above is performed for a predetermined time. It is preferable to repeat the operation at intervals because it is possible to reduce the cost by using a commercially available device. However, the present invention is not limited to this, and the pneumatic tire is rotated by the temperature sensor 3 using a high-performance processing means. The surface temperature of 2 is continuously measured continuously, and the amount of temperature change at each corresponding position on the tire circumference is obtained using the front and back surface temperature data measured at a predetermined time interval. Good.
[0031]
As the non-contact type temperature sensor 3, the above-described infrared image reading thermometer that detects infrared rays can be preferably used. However, the non-contact type temperature sensor 3 is naturally not limited to this, and may be a non-contact type that can measure the tire surface temperature. Other embodiments may be used.
[0032]
The tire failure detection method and apparatus of the present invention described above can be preferably used in a tire durability test, but can also be applied to, for example, an apparatus that is mounted on a vehicle and detects a tire failure. In that case, an alarm generating means for generating an alarm is connected to the processing means 4 so that when the processing means 4 determines that an internal failure of the tire has occurred, the alarm generating means notifies the driver of it. Is good.
[0033]
【The invention's effect】
The present invention as described above, using a non-contact type temperature sensor, the difference in temperature variation on the circumference of the surface temperature data before and after the measured at a predetermined time interval is equal to or greater than a predetermined threshold value In this case, it is determined that an internal failure has occurred. Therefore, the internal failure can be detected regardless of the amount of bulging of the tire surface, and therefore, the tire failure can be detected with higher accuracy than in the past.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an example of implementing a tire failure detection method of the present invention in a tire durability test.
FIG. 2 is a flowchart showing a tire failure detection method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Test drum 2 Pneumatic tire 3 Non-contact-type temperature sensor 4 Processing means 5 Wheel

Claims (9)

A tire failure detection method for detecting impaired internal late occurred pneumatic tire rotates,
More non-contact temperature sensor which is installed to face the pneumatic tire to the rotating, the surface temperature of a pneumatic tire to the rotating repeats the steps of measuring over one round along the tire circumferential direction, and the rotating the amount of change before and after the predetermined time interval of the measured surface temperature at each corresponding position on the tire circumference of the tire was calculated, the difference between the change amount the calculated is equal to or larger than a predetermined threshold value tire failure detection method determines that the internal mechanical failure has occurred when it becomes. The tire failure detection method according to claim 1 , wherein the step of measuring the surface temperature of the rotating tire over the entire circumference in the tire circumferential direction is performed at each predetermined time interval. The tire failure detection method according to claim 1 or 2 non-contact type temperature sensor is infrared image reading thermometer. Each corresponding position on the tire circumference of the rotating tire is identified by detecting reflected light of light applied to a reflection sheet attached to a sidewall portion or a rim portion of the rotating tire. 4. The tire failure detection method according to any one of 3. A tire failure detection device for detecting an internal fault occurs in the pneumatic tire rotates,
A non-contact temperature sensor installed facing the rotating pneumatic tire; and processing means for processing a detection signal from the temperature sensor, wherein the processing means is rotated by the non-contact temperature sensor. Change of the surface temperature before and after each predetermined time interval at each corresponding position on the tire circumference of the rotating tire from the surface temperature repeatedly measured over one circumference along the tire circumferential direction of the pneumatic tire the amount was calculated, the difference is a tire failure detection device determines that generates an internal fault if it becomes more than a predetermined threshold value between the variation of the calculated. The tire failure detection device according to claim 5 , wherein the step of repeatedly measuring the surface temperature of the rotating tire by the non-contact temperature sensor over the entire circumference along the tire circumferential direction is performed at each predetermined time interval. The tire failure detection device according to claim 5 or 6 non-contact type temperature sensor is infrared image reading thermometer. The tire according to any one of claims 5 to 7 , wherein an alarm generating means is connected to the processing means, and the alarm generating means generates an alarm when it is determined that the processing means has detected the internal failure. Failure detection device. A reflective sheet is attached to the sidewall or rim of the rotating tire, and the corresponding position on the tire circumference of the rotating tire is identified by detecting the reflected light of the light irradiated on the reflective sheet. The tire failure detection device according to any one of claims 5 to 8 .

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