JP2008149803A - Method and device for sensing tire failure, and tire for sensing failure inside tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately sense breakage inside a tire without influences on behaviors of the tire. <P>SOLUTION: A rubber magnet 11 is embedded inside a tire such as a belt end, a ply folded end and a bead filler part of a tire 20, and magnetic field measuring means 12 is arranged near the rubber magnet 11 outside the tire 20, so as to detect a waveform of an elapsed time of a magnetic field H from a rolling tire. A waveform difference value K between the detected magnetic field waveform and a pre-found magnetic field waveform when crack does not occur inside the tire is calculated, so as to sense whether the inside of the tire is broken or not based on the waveform difference value K. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for detecting a tire failure, and more particularly to detection of a tire failure caused by a crack generated inside the tire.

In a tire, a carcass ply or a belt is attached and used as a skeleton member, but when the tire rotates at a high speed, a large stress acts on the end of the belt, so a crack is generated between the belt layer and the surrounding rubber. May occur and the belt end may be destroyed. Such destruction of the belt end portion causes the both ends of the belt layer in the width direction to rise, and as a result, the steering stability performance is greatly reduced, which may lead to a serious accident. Further, during high-speed rotation, a large shearing force may act on the rubber in the bead filler portion sandwiched between the carcass ply and the bead core that wraps around the bead core, causing cracks to be generated and breaking. Therefore, it is necessary to promptly detect a failure due to such a crack generated in the tire.
On the other hand, when a tire breaks down, the heat at the failure point increases, and the temperature near the failure point resonates, so a method of measuring the temperature of the running tire using a temperature sensor and detecting the tire failure from this temperature Has been proposed.
FIG. 6 is a diagram showing an example of a configuration of a conventional tire failure detection device. A temperature sensor 31 that measures the temperature of a tire and a transmission signal that transmits a detection signal of the temperature sensor 31 to the vehicle body side via a transmission antenna 33. As shown in FIG. 7, the temperature sensor unit 30 including the portion 32 includes a vicinity of the end 51 a of the belt layer 51 of the pneumatic tire 50, a vicinity of the end 52 a of the carcass layer 52, and a tire tread 53. In the vehicle mounting unit 40, the temperature of each part is measured and transmitted to the vehicle mounting unit 40 provided on the vehicle body side, and the vehicle mounting unit 40 receives the signal with the receiving antenna 41 provided in the receiving unit 42. The processing unit 43 compares the temperature data of each part and the preset warning temperature. When the measured temperature exceeds the warning temperature, the warning unit 44 is activated. Te so that alert the driver (for example, see Patent Document 1).
JP 2005-67447 A

  However, in the conventional method, a foreign matter having high rigidity such as the temperature sensor unit 30 is embedded at the belt end portion, which may cause a tire failure as a core of a new crack. In particular, when the temperature sensor unit 30 is disposed at the belt end where a large stress acts when the tire rolls, the belt end is likely to be broken.

  The present invention has been made in view of the conventional problems, and an object of the present invention is to accurately detect destruction inside the tire such as a belt end without affecting the behavior of the tire.

As a result of intensive studies, the inventors have not only affected the behavior of the tire if the rubber magnet is embedded in the tire, such as the belt end, but also the location where the rubber magnet is embedded in the tire. Since the rubber magnet is destroyed at the same time when it is destroyed, it is found that if the magnetic field generated by the rubber magnet is measured, the destruction inside the tire can be detected from the change in the magnetic field. It is.
That is, the invention according to claim 1 of the present application is a method for detecting a failure of a tire, in which a rubber magnet is disposed inside the tire and a magnetic field measuring means is disposed in proximity to the tire during rolling. A magnetic field from the tire is measured, and destruction inside the tire is detected based on the magnitude or magnetic field waveform of the measured magnetic field.
Invention of Claim 2 is the tire failure detection method of Claim 1, Comprising: The said rubber magnet is any one of the belt edge part of a tire, a ply edge part, a ply folding | turning edge part, and a bead filler part. It is arranged at one place, plural places or all places.

The invention according to claim 3 is a tire failure detection device for detecting a failure of a tire, a rubber magnet disposed inside the tire, a magnetic field measuring means disposed in the vicinity of the tire, and this And a failure detection means for detecting destruction of the inside of the tire based on the output of the magnetic field measurement means.
According to a fourth aspect of the present invention, in the tire failure detection device according to the third aspect, the rubber magnet may be any one of a belt end portion, a ply end portion, a ply folded end portion, and a bead filler portion of the tire. It is arranged at a place, a plurality of places, or all places.
The invention according to claim 5 is the tire failure detection device according to claim 3 or claim 4, wherein the failure detection means is a magnetic field when no crack is generated inside the tire determined in advance. A storage means for storing a standard magnetic field waveform that is a waveform, a waveform difference calculating means for calculating a waveform difference that is a difference between the standard magnetic field waveform and the measured magnetic field waveform, and the inside of the tire based on the waveform difference, It is comprised from the determination means which determines whether it has destroyed.
According to a sixth aspect of the present invention, in the tire failure detection device according to any one of the third to fifth aspects, an alarm unit is further provided that issues an alarm when the failure detection unit detects a breakage inside the tire. It is a thing.
The invention according to claim 7 is a tire capable of detecting a failure caused by a crack generated inside the tire, and is characterized in that a rubber magnet is arranged inside the tire.
The invention according to claim 8 is the tire for detecting an internal failure of the tire according to claim 7, wherein the rubber magnet includes a belt end portion, a ply end portion, a ply folded end portion, and a bead filler portion of the tire. It is arranged at any one place, a plurality of places, or all places.

According to the present invention, the belt end portion of the tire, the ply end portion, the ply turn-up end portion, and the bead filler portion, and the like (at the inside of the tire) where failure such as destruction is a concern when a large stress is applied. A rubber magnet is disposed, and a magnetic field measuring means is disposed in the vicinity of the tire to measure the magnetic field from the rolling tire. Based on the measured magnetic field magnitude or magnetic field waveform, the tire interior Since the destruction of the tire is detected, the destruction inside the tire can be accurately detected without affecting the behavior of the tire.
At this time, a standard magnetic field waveform that is a magnetic field waveform when no crack is generated inside the tire is obtained in advance, and if this standard magnetic field waveform is compared with the measured magnetic field waveform, the inside of the tire is destroyed. It can be accurately determined whether or not.
In addition, if an alarm means is provided to issue an alarm when the inside of the tire is detected, measures such as replacing the tire can be taken before the inside of the tire becomes large, preventing accidents due to tire failure. be able to.

Hereinafter, the best mode of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a tire failure detection device 10 according to the best mode, and FIG. 2 is a cross-sectional view of a main part of a belt end failure detection tire 20 according to the present invention. In each figure, 11 is a rubber magnet embedded in an end portion 23a of a belt 23 provided between a tread 21 and a carcass ply 22 of a belt end failure detection tire (hereinafter referred to as a tire) 20, and 12 is the tire described above. Magnetic field measuring means for measuring the magnetic field from the tire 20 in which the rubber magnet 11 is embedded, which is disposed outside the belt end portion 23a on the outer side of the belt 20, and 13 is a wheel speed sensor for detecting the rotational speed of the tire. , 14 is a magnetic field waveform detecting means for detecting the magnetic field waveform of the rolling tire from the output of the magnetic field measuring means 12, and 15 is a standard waveform to be described later on the detected magnetic field waveform based on the output of the wheel speed sensor. Magnetic field waveform converting means 16 for converting to a vehicle speed waveform corresponding to the vehicle speed at the time of measurement, 16 is the previously calculated bell that is stored in the converted magnetic field waveform and storage means 17. Waveform difference calculating means 18 for calculating a waveform difference that is a difference from a standard magnetic field waveform that is a magnetic field waveform when no crack is generated at the end, 18 is a belt end breakage from the magnitude of the calculated waveform difference The failure determination means 19 for determining whether or not the failure has occurred is an alarm means for warning the driver of the belt end breakage based on the result of the failure determination means 18.

In this example, the magnetizing direction of the rubber magnet 11 is magnetized so that the rubber magnet 11 becomes a vertical direction when the rubber magnet 11 comes to the opposite side of the ground contact surface of the tire 20, and the magnetic field measuring means 12 is set to the tire. However, with respect to the magnetization direction of the rubber magnet 11 and the position where the magnetic field measuring means 12 is arranged, the magnetic field from the rubber magnet 11 is sufficient. There is no particular limitation as long as it can be detected. For example, in the case of a tire having a diameter of about 700 mm, the distance between the tread 21 and the magnetic field measuring means 12 is preferably 50 mm or less, and particularly preferably about 15 mm.
In this example, a magnetic sensor using a magnetoresistive element is used as the magnetic field measuring means 12, but other magnetic sensors such as a magnetic sensor using a Hall element may be used.

Next, operation | movement of the tire failure detection apparatus 10 by this invention is demonstrated.
First, the magnetic field from the tire 20 is continuously detected by the magnetic field measuring means 12. FIG. 3 is a diagram showing a time-change waveform (magnetic field waveform) of the magnetic field H from the moving tire 20 measured by the magnetic field measuring means 12 and detected by the magnetic field waveform detecting means 14. The thin solid line (thick solid line) Is the magnetic field waveform (standard magnetic field waveform) when there is no crack at the end of the belt obtained in advance, and the one shown by the thick solid line is It is a magnetic field waveform when the belt end portion is broken, which is measured at the same wheel speed as that during the standard magnetic field waveform measurement. Since the tire 20 includes magnetized members such as the belt 23 and the bead portion 24 in addition to the rubber magnet 11, the magnetic field waveform is a periodic waveform accompanying rotation as shown in FIG.
When obtaining the waveform difference value K, which is the difference between the magnetic field magnetic field waveform from the rotating tire 20 detected by the magnetic field waveform detecting means 14 and the standard magnetic field waveform, it is necessary to align the wheel speeds. Therefore, in this example, magnetic field waveform conversion means 15 is provided to convert the detected magnetic field waveform into a vehicle speed waveform corresponding to the vehicle speed at the time of standard waveform measurement based on the output of the wheel speed sensor 13, and this conversion is performed. The measured magnetic field waveform is sent to the waveform difference calculating means 16 to calculate the waveform difference from the standard magnetic field waveform.
FIG. 4 is a diagram showing the time change of the difference (ΔH) between the magnetic field waveform detected by the magnetic field waveform detecting means 14 and the standard magnetic field waveform, and this difference ΔH is also a periodic waveform.
That is, when the crack generated in the belt end portion is developed and the belt end portion is broken, the rubber magnet 11 is also cracked. Therefore, the magnetic field generated by the rubber magnet 11 is reduced. The magnetic field from does not change. Therefore, ΔH which is the difference between the magnetic field waveform detected by the magnetic field waveform detecting means 14 and converted by the magnetic field waveform converting means 15 and the standard magnetic field waveform stored in the storage means 17 by the waveform difference calculating means 16. The peak value is extracted and sent as a waveform difference value K to the failure determination means 18. The failure determination means 18 compares the waveform difference value K with a preset threshold value. When the waveform difference value K exceeds the threshold value, it is determined that the belt end is broken.
When the failure determination means 18 determines that the belt end portion is broken, the alarm means 19 issues an alarm to the driver by turning on a lamp or the like. As a result, measures such as tire replacement can be taken before the end of the belt breaks down, so accidents due to tire failures can be prevented.

  Thus, according to this best mode, the rubber magnet 11 is embedded in the belt end portion 23a of the tire 20, and the magnetic field measuring means 12 is disposed outside the tire 20 in the vicinity of the rubber magnet 11. A time-dependent waveform of the magnetic field H from the rolling tire is detected, and the detected magnetic field waveform and a standard magnetic field waveform that is a magnetic field waveform obtained when a crack is not generated in the belt end portion obtained in advance. The waveform difference value K, which is the difference between the two, is calculated, and based on this waveform difference value K, it is detected whether the belt end has been destroyed and an alarm is issued to the driver. It is possible to take measures such as exchanging tires before the tire becomes large, and to prevent accidents caused by tire failures.

  In the above-described best mode, the case where the rubber magnet 11 is disposed on the belt end portion 23a of the tire 20 has been described. However, the ply folded end portion, the bead filler portion, and the like are also damaged due to large stress during high-speed rotation. Therefore, as shown in FIG. 5, the bead is a reinforcing rubber member sandwiched between the folded end portion 22a of the carcass ply 22 and the bead core 24c of the bead portion 24 and the folded carcass ply 22. It is preferable to place the rubber magnet 11 on the filler portion 25 and the like so as to detect cracks and breakage of the portion. Note that a plurality of the rubber magnets 11 may be disposed over the entire circumference of the tire, or may be partially disposed at an arbitrary location.

In the above example, the magnetic field magnetic field waveform from the moving tire 20 detected by the magnetic field waveform detecting means 14 is converted into a vehicle speed waveform corresponding to the vehicle speed at the time of standard waveform measurement, and then the waveform with the standard magnetic field waveform. The difference is calculated, but the magnetic field waveform is periodic, so if you convert the magnetic field waveform with time on the horizontal axis into a magnetic field waveform with the tire position on the horizontal axis, the waveform difference will be calculated regardless of the wheel speed. It can be calculated.
In the above example, the peak value of the waveform difference ΔH is the waveform difference value K. However, the waveform difference value K is not limited to this, and an integrated value of ΔH is calculated and used as the waveform difference value. Another amount obtained from the waveform of the waveform difference ΔH may be used as the waveform difference value.
In addition, it is not always necessary to obtain the waveform difference of the magnetic field waveform in order to detect the destruction of the inside of the tire such as the belt end portion 23a, simply by setting a threshold value to the peak value of the magnetic field waveform and detecting the peak value of the detected magnetic field waveform. It may be determined that the tire is malfunctioning when is below a predetermined threshold. However, when a plurality of rubber magnets 11 are embedded in the tire and a plurality of tire failures are detected in parallel, it is necessary to set a peak value position and a threshold value, as in this example. It is preferable to use the waveform difference.

  As described above, according to the present invention, it is possible to accurately detect the destruction inside the tire without affecting the behavior of the tire, so it is possible to detect the failure of the tire in advance, and the safety of the vehicle. Can be improved.

It is a figure which shows the structure of the tire failure detection apparatus which concerns on the best form of this invention. It is sectional drawing which shows the structure of the tire for belt end failure detection by this invention. It is a figure which shows an example of a magnetic field waveform. It is a waveform of the difference of the magnetic field waveform at the time of normal of a belt edge part, and the magnetic field waveform at the time of destruction. It is sectional drawing which shows the other example of arrangement | positioning of a rubber magnet. It is a figure which shows one structural example of the conventional tire failure detection apparatus. It is a figure which shows the embedding location of the temperature sensor unit used for the conventional tire failure detection apparatus.

Explanation of symbols

10 tire failure detection device, 11 rubber magnet, 12 magnetic field measuring means,
13 wheel speed sensor, 14 magnetic field waveform detecting means, 15 magnetic field waveform converting means,
16 waveform difference calculation means, 17 storage means, 18 failure determination means, 19 alarm means,
20 Belt end failure detection tire, 21 tread, 22 carcass ply,
22a Folding end of carcass ply, 23 belt, 23a belt end,
24 bead parts, 24c bead core, 25 bead filler parts.

Claims (8)

  A rubber magnet is arranged inside the tire, and a magnetic field measuring means is arranged in the vicinity of the tire to measure the magnetic field from the rolling tire. Based on the measured magnetic field magnitude or magnetic field waveform, A tire failure detection method, comprising detecting destruction inside a tire.   2. The rubber magnet according to claim 1, wherein the rubber magnet is disposed at any one, plural, or all of a belt end portion, a ply end portion, a ply folded end portion, and a bead filler portion of the tire. Tire failure detection method.   A rubber magnet arranged inside the tire, a magnetic field measuring means arranged close to the tire, and a failure detecting means for detecting destruction inside the tire based on the output of the magnetic field measuring means A tire failure detection device.   4. The rubber magnet is disposed at any one, a plurality of, or all of a belt end portion, a ply end portion, a ply folded end portion, and a bead filler portion of a tire. The tire failure detection device described in 1.   The failure detection means includes a storage means for storing a standard magnetic field waveform which is a magnetic field waveform when no crack is generated in the tire, and a difference between the standard magnetic field waveform and the measured magnetic field waveform. 5. A waveform difference calculating means for calculating the waveform difference, and a determining means for determining whether or not the inside of the tire is destroyed based on the waveform difference. The tire failure detection device described in 1.   6. The tire failure detection device according to claim 3, further comprising alarm means for issuing an alarm when the failure detection means detects destruction inside the tire.   A tire for detecting an internal failure of a tire, characterized in that a rubber magnet is disposed therein.   The said rubber magnet is arrange | positioned in the belt edge part of a tire, a ply edge part, a ply folding | turning edge part, and one place, multiple places, or all the places of a bead filler part. The tire for tire internal failure detection described in 1.

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