JP4561455B2 - Tire failure detection method and apparatus - Google Patents

Description

  The present invention relates to a method and an apparatus for detecting a failure of a tire rotating on a drum in a tire endurance test, and more specifically, to accurately detect even a tire failure with a very slow traveling speed generated in a sidewall portion. TECHNICAL FIELD The present invention relates to a tire failure detection method and apparatus capable of performing the same.

  In the tire durability test in the room, if the durability test is continued in a state where a tire failure has occurred, the tire may burst. Therefore, it is desired to detect the failure promptly and terminate the test when a failure occurs in the tire.

  Conventionally, as a device for detecting a failure of a tire rotating on a drum in a tire endurance test, a tire is formed by extending a thin line along the outer edge in the meridian direction of the tire and contacting the raised failure point of the tire with the thin line A contact type that detects a failure has been proposed (see, for example, Patent Document 1).

However, in the contact type detection device as described above, in order to avoid malfunction, it is necessary to separate the thin line that becomes the detection unit from the tire surface by a predetermined distance. As a result, when a tire failure occurs and the progress speed is extremely slow, the amount of bulging caused by the failure does not readily reach the distance away from the detection unit even though the failure occurs. There was a problem that failure detection was delayed.
JP 2004-77464 A

  An object of the present invention is to provide a tire failure detection method and apparatus capable of accurately detecting even a tire failure that occurs at a sidewall portion and has a very slow traveling speed.

  A tire failure detection method of the present invention that achieves the above object is a method for detecting a failure of a tire that rotates on a drum in a tire durability test, and includes a plurality of tires that are centered on a tire rotation axis on a surface of a sidewall portion of the tire. In this case, it is determined that a tire failure has occurred when at least one of a predetermined amount of local distortion and cracking occurs in any of the concentric circles.

  The tire failure detection device of the present invention is a device for detecting a failure of a tire rotating on a drum, displaying a plurality of concentric circles centered on a tire rotation axis on a sidewall portion surface in a tire endurance test, Image input means for capturing images of a plurality of concentric circles of the tire rotating on the drum, and a predetermined amount of local distortion and cracks in any one of the concentric circles from the image signals of the concentric circles input from the image input means. And image processing means for determining whether or not at least one has occurred and determining that a tire failure has occurred when determining that it has occurred.

  According to the above-described present invention, by using a tire having a plurality of concentric circles centered on the tire rotation axis on the sidewall surface, it is possible to determine that a tire failure has occurred from the distortion of the concentric circles. Therefore, the occurrence of a tire failure can be detected in a non-contact manner by an image input means or the like. Therefore, there is no problem of the distance to arrange the detection part using the contact type, and therefore, even if a tire failure with a very slow traveling speed occurring in the sidewall part can be detected at an early stage, the tire failure It becomes possible to improve the detection accuracy of the.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of a tire failure detection device according to the present invention. This tire failure detection device X is a device that detects a failure of a tire 2 that rotates on a drum 1 in a tire durability test.

  As the tire 2 for performing the durability test, as shown in FIG. 2, a tire having a plurality of concentric circles 3 centered on the tire rotation axis O on the entire surface 2a of the sidewall portion 2A is used. The concentric circle 3 is preferably displayed in white for easy recognition, but any color or display form may be adopted as long as it can be distinguished from the surface 2a of the sidewall portion 2A.

  The interval s (see FIG. 3) between adjacent concentric circles 3 can be practically in the range of 0.1 mm to 30 mm, and is appropriately selected depending on the size of the tire to be tested. If the interval s is smaller than 0.1 mm, it is difficult to write concentric circles 3 adjacent to each other with an interval. On the contrary, if it exceeds 30 mm, there is a possibility that the interval becomes too wide and the detection accuracy is lowered.

  The tire failure detection device X is input from the image input means 4 including a video camera that captures images of a plurality of concentric circles 3 provided on the sidewall 2 surface 2a of the tire 2 rotating on the drum 1. In addition, image processing means 5 comprising a personal computer that determines that a tire failure has occurred when local distortion occurs in any one of the concentric circles 3 from image signals of a plurality of concentric circles 3 is provided.

  The image input means 4 is a tire that is installed to face one sidewall portion surface 2a of the tire 2 that is rotatably supported by a tire durability tester main body (not shown) with the tire rotation axis O being horizontal. The plurality of concentric circle 3 portions 3a passing through the facing positions by 2 can be taken in at the same time. Image signals of a plurality of concentric circles 3 captured by the image input unit 4 are input to the image processing unit 5.

  The image processing means 5 determines whether or not a predetermined amount of local distortion has occurred in each concentric circle 3 from the input image signal data. When a tire failure occurs in the sidewall portion 2A of the tire 2 rotating on the drum 1, the portion of the surface 2a corresponding to the position of the tire failure locally rises, and as shown in FIG. 3, the raised portion In FIG. 6, the concentric circle 3 is locally deformed and distortion occurs. The tire failure is found from the local distortion.

  Therefore, the image processing means 5 recognizes each concentric circle 3 from the image data in accordance with an image processing program inputted in advance, and calculates the distortion amount in each portion 3a of each recognized concentric circle 3. When the calculated strain amount exceeds a preset threshold value, it is determined that a predetermined amount of local strain has occurred, and it is determined that a tire failure has occurred.

  The distortion amount a (see FIG. 4) serving as a threshold can be set in a range of about 0.2 mm to 3 mm. Since the degree of distortion of concentric circles due to tire failure differs depending on the rubber used in the tire, the structure, the size, the measurement position of the sidewall portion 2A, and the like, it is appropriately selected from this range. If the strain amount a is smaller than this range, there is a risk of erroneous detection. Conversely, if the strain amount a is larger than this range, the tire may burst.

  When the image processing means 5 determines that a predetermined amount of local distortion has occurred in any of the concentric circles 3 and a tire failure has occurred, the tire failure has occurred in the control unit 7 of the tire durability tester that controls the rotation of the drum 1. A signal notifying that it has occurred is output, and the control section 7 receives this signal, stops the rotation of the drum 1 and ends the tire durability test.

  In the tire endurance test, the tire rotation speed and / or tire load may be changed stepwise (usually increased stepwise) in some cases. In that case, when the tire rotation speed or the tire load is changed, the tire 2 is deformed, and therefore the size of the concentric circle 3 is changed. In order to prevent this change from being erroneously determined as distortion, when the control unit 7 outputs a control signal for changing the tire rotation speed or / and the tire load, a signal for stopping the processing is output to the image processing means 5. In response to the signal, the image processing means 5 stops the calculation of the distortion amount of the concentric circle 3 and stops the judgment of the tire failure. After the change, the control unit 7 keeps the tire rotational speed or / and the tire load load constant. When the control is performed, a signal for releasing the stop is output to the image processing means 5, and upon receiving the signal, the image processing means 5 restarts the calculation of the amount of distortion of the concentric circle 3 and determines a tire failure. Good.

  When the time to change in steps is known in advance, the determination of the tire failure is stopped when the time to change the image processing means 5 comes without using the signal from the control unit 7. be able to.

  Further, when a tire durability test is performed by continuously changing (continuously increasing) the tire rotation speed and / or tire load load, image processing is performed using the amount of change per unit time of the concentric circle 3 that is deformed. The means 5 can be configured to determine a tire failure.

  Hereinafter, the tire failure detection method of the present invention will be described using the above-described tire failure detection device X. In the method of the present invention, a plurality of tire rotation tests are performed on the surface 2a of the sidewall portion 2A in the tire durability test. The tire 2 displaying the concentric circle 3 is used, and the tire 2 is rotated on the drum 1. The image of the sidewall surface 2 a including the plurality of concentric circle 3 portions 3 a of the rotating tire 2 is sequentially captured by the image input means 4, and the image signal is input to the image processing means 5.

  The image processing means 5 determines whether or not a predetermined amount of local distortion has occurred in any of the concentric circles 3 from the input image signal data of the portions 3a of the plurality of concentric circles 3. If the image processing means 5 determines that a predetermined amount of local distortion has occurred in any of the concentric circles 3, it is determined that a tire failure has occurred, and the tire durability tester control unit 7 for controlling the rotation of the drum 1 has tires. A signal notifying that a failure has occurred is output, and the control unit 7 stops the rotation of the drum 1 and ends the tire durability test.

  When the tire endurance test is performed by changing the tire rotation speed or / and the tire load load stepwise, as shown in FIG. 5, the stop output when the tire rotation speed or / and the tire load load is changed. The image processing means 5 determines whether or not the tire rotational speed or / and the tire load load has been changed based on whether or not the signal is input from the control unit 7. If there is no stop signal, the distortion amount of the concentric circle 3 is calculated. To do. When the calculated strain amount exceeds a preset threshold value, it is determined that a predetermined amount of local strain has occurred and a tire failure has occurred, and a tire failure has occurred in the control unit 7 of the tire durability tester. A signal informing that is output and the failure detection is terminated. When a stop signal is input from the control unit 7, the image processing means 5 does not calculate the amount of distortion of the concentric circle 3 until a cancel signal is input.

  According to the present invention described above, in the tire endurance test, the tire 2 in which a plurality of concentric circles 3 around the tire rotation axis O are displayed on the surface 2a of the sidewall portion 2A is used as the tire to be tested. Since the occurrence of the tire failure is determined from the distortion, the tire failure can be detected in a non-contact manner by the image input means 4 or the like. Therefore, even if the tire failure occurs at the sidewall portion 2A and the traveling speed is very slow, the tire failure can be detected at an early stage before the tire bursts, and the detection can be performed with high accuracy.

  In the present invention, in the above embodiment, the tire failure is detected using the distortion of the concentric circle 3 provided on the tire 2, but when the surface 2a is locally raised due to the tire failure, in the raised portion 6, As shown in FIG. 6, the concentric circles 3 are not continuous, and cracks 8 are locally broken. Therefore, the image processing means 5 determines whether or not a predetermined amount of local cracks 8 have occurred in any of the concentric circles 3 instead of the above-described distortion, and determines that a tire failure has occurred when it is determined that such a crack has occurred. You may make it do. Alternatively, both the concentric circle 3 strain and the crack 8 may be used, and it is determined that a tire failure has occurred when at least one of a predetermined amount of local strain and crack occurs in any of the concentric circles 3. What should I do?

  Further, when a protrusion such as a brand mark is formed on the surface 2a of the sidewall portion 2A, the image input means 4 as an image in which the concentric circles 3 formed on the surface 2a are distorted from the beginning due to the unevenness. May be read. In that case, the image of the concentric circle 3 for one turn of the tire is inputted to the image processing means 5 through the image input means 4 at the stage before entering the test, and the image data of the concentric circle 3 for one turn of the tire is used as a reference. It is preferable to store the data in a memory and determine the distortion of the concentric circle 3 by using the difference (difference at each corresponding position) between the reference data and the data obtained during the test.

It is a front view which shows one Embodiment of the tire failure detection apparatus of this invention. It is a side view of the tire of FIG. It is the elements on larger scale which show the example which the local distortion produced in the concentric circle provided in the sidewall part surface of the tire of FIG. It is explanatory drawing which shows the amount of distortion of a concentric circle. It is a flowchart which shows the tire failure detection method in the case of performing a tire durability test by changing a tire rotational speed or / and a tire load load in steps. It is explanatory drawing which shows the example of the crack which the concentric circle interrupted locally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drum 2 Tire 2A Side wall part 2a Surface 3 Concentric circle 4 Image input means 5 Image processing means 6 Raised part 8 Crack O Tire rotation axis X Tire failure detection apparatus

Claims (7)

  A method for detecting a failure of a tire rotating on a drum in a tire endurance test, wherein a tire having a plurality of concentric circles centered on a tire rotation axis on the surface of the sidewall is used as the tire, and any one of the concentric circles is used. A tire failure detection method for determining that a tire failure has occurred when at least one of a predetermined amount of local distortion and cracking occurs.   A plurality of concentric images of the tire rotating on the drum are input to the image processing means by the image input means, and a predetermined amount of local image is applied to any one of the concentric circles from the plurality of concentric image signals input by the image processing means. The tire failure detection method according to claim 1, wherein it is determined whether or not at least one of a general distortion and a crack has occurred, and it is determined that a tire failure has occurred when it is determined that the failure has occurred.   The tire failure detection method according to claim 1 or 2, wherein an interval between adjacent concentric circles is 1 mm to 30 mm.   4. The tire failure detection method according to claim 1, wherein when the tire endurance test changes tire rotation speed or / and tire load load stepwise, the determination of the tire failure is stopped at the time of change.   In a tire endurance test, a device for detecting a failure of a tire rotating on a drum and displaying a plurality of concentric circles centered on a tire rotation axis on a sidewall portion surface, the plurality of tires rotating on the drum It is determined whether or not at least one of a predetermined amount of local distortion and crack has occurred in any of the concentric circles from the image input means for capturing the concentric image and a plurality of concentric image signals input from the image input means. A tire failure detection apparatus comprising: an image processing unit that determines that a tire failure has occurred when it is determined that a tire failure has occurred.   The tire failure detection device according to claim 5, wherein an interval between adjacent concentric circles is 1 mm to 30 mm. The tire according to claim 5 or 6, wherein when the tire endurance test changes the tire rotation speed or / and the tire load load stepwise, the image processing means stops judging the tire failure at the time of the change. Failure detection device.

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