JP6852586B2 - Tire abnormality detection method and abnormality detection device - Google Patents

Description

The present invention relates to a tire abnormality detection method for detecting a tire abnormality and an abnormality detection device.

As a method for detecting abnormalities such as cracks, cracks, peeling, and scratches that occur in a tire, for example, the one disclosed in Patent Document 1 is known. In Patent Document 1, magnetic materials are provided on the surface of a tire at a predetermined pitch, and magnets are provided at appropriate positions on the vehicle body side at positions facing each magnetic material to form an annular magnetic path. Then, the change in the magnetic flux density that occurs in the annular magnetic path with the rotation of the tire is detected, and the abnormality of the tire is detected based on the change in the magnetic flux density.

Japanese Patent No. 4198414

However, in the conventional example disclosed in Patent Document 1 described above, since the abnormality of the tire is detected based on the change in the magnetic flux density, it is an indispensable requirement that the tire is rotating, and the tire is stopped. There was a problem that it was difficult to detect anomalies below.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a tire abnormality detection method and an abnormality detection device capable of easily detecting a tire abnormality. To provide.

In order to achieve the above object, the present invention is a tire abnormality detection method having a secondary resonance circuit provided on the tire side and detecting a tire abnormality based on a change in impedance of the secondary resonance circuit. , The fiber reinforcing layer of the tire, and the electrodes arranged on at least one of the load supporting structures are used to form a capacitor of the secondary resonance circuit, and the detected abnormality of the tire is transmitted to the vehicle body side by an electric signal or an electromagnetic wave.

According to the present invention, it is possible to easily detect an abnormality in a tire.

FIG. 1 is a block diagram showing a configuration of a tire abnormality detection device according to a first embodiment of the present invention. FIG. 2A is a side sectional view of the non-pneumatic tire. FIG. 2B is an enlarged view of the “α” portion shown in FIG. 2A. FIG. 3 is a partially broken perspective view of the non-pneumatic tire. FIG. 4 is a perspective view showing a state in which a fiber reinforcing layer is provided on the outer peripheral portion of the coated rubber. FIG. 5 is a perspective view showing a state in which a conductive wire is provided on the side surface of the load support structure to form a coil of a secondary resonance circuit. FIG. 6 is an explanatory diagram showing how the coil provided in the load support structure and the coil provided in the primary resonance circuit are electromagnetically coupled. FIG. 7 is an equivalent circuit diagram of the tire abnormality detection device according to the first embodiment of the present invention. FIG. 8 is a block diagram showing a configuration of a tire abnormality detection device according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a tire abnormality detection device according to a first embodiment of the present invention. As shown in FIG. 1, the abnormality detection device according to the present embodiment includes a vehicle body side circuit 10 provided on the vehicle body side and a tire side circuit 20 provided on the tire side.

The tire side circuit 20 includes a secondary resonance circuit 21 including a coil and a capacitor. Further, the vehicle body side circuit 10 detects a primary resonance circuit 11 including a coil and a capacitor, an AC signal generation circuit 12 that supplies an AC signal to the primary resonance circuit 11, and a current or voltage flowing through the primary resonance circuit 11. The tire abnormality detection circuit 13 for detecting abnormalities such as cracks, cracks, and peeling that occur in a tire based on a change in current or voltage is provided.

FIG. 2A is a side sectional view of the non-pneumatic tire 30 (hereinafter, abbreviated as “tire 30”) to be detected for abnormality, and FIG. 2B is an enlarged view of the “α” portion shown in FIG. 2A. 3 is a partially broken perspective view of the tire 30.

As shown in FIG. 2A, the tire 30 is provided with a wheel 31 having a circular side view in the center, and further, a load support structure 39 for supporting the tire 30 is provided around the wheel 31. The load support structure 39 has a plurality of spokes 32 (8 in the figure) provided from the wheel 31 toward the outer peripheral side, and a side view circular outer peripheral ring 33 provided at the tip of each spoke 32. There is. The outer peripheral ring 33 is made of, for example, a silicone-based, urethane-based, or epoxy-based resin.

As shown in FIGS. 2B and 3, a conductor layer 34 is provided on the outer peripheral portion of the outer peripheral ring 33. The conductor layer 34 is made of a mesh of a conductive material, a plate material, or the like.
An outer peripheral rubber portion 38 is formed on the outer peripheral portion of the conductor layer 34. The outer peripheral rubber portion 38 includes a coated rubber 35 in contact with the conductor layer 34, a fiber reinforcing layer 36 formed on the outer peripheral portion of the coated rubber 35, and a tread portion 37 formed on the outer peripheral portion of the fiber reinforcing layer 36. ing.

The fiber reinforcing layer 36 is a layer for improving the strength of the outer peripheral rubber portion 38, and is configured by arranging conductive electric wires in a mesh shape.
FIG. 4 is a perspective view showing a state in which the fiber reinforcing layer 36 is provided on the outer peripheral portion of the coated rubber 35. Each electric wire forming the fiber reinforced layer 36 is coated, and further, the coating is peeled off at the side portion of the tire 30. Then, in the present embodiment, the annular conductor 40 is arranged so as to go around the end of the fiber reinforced layer 36, and each electric wire forming the fiber reinforced layer 36 is electrically conducted.

With the above configuration, the conductive conductor layer 34 and the fiber reinforcing layer 36, which also has conductivity, are arranged to face each other via the coated rubber 35, and thus function as a capacitor having a capacitance. This is referred to as a capacitor C2. That is, the capacitor C2 is a capacitor (C2 shown in FIG. 7 described later) provided in the secondary resonance circuit 21 of FIG. 1 described above.

FIG. 5 is an explanatory view showing a conductive wire arranged in the load support structure 39 of the tire 30. In FIG. 5, the description of the conductor layer 34 and the outer peripheral rubber portion 38 provided on the outer periphery of the load support structure 39 is omitted.

As shown in FIG. 5, conductive wires 41a forming a loop along one side surface and the other side surface (that is, both side surfaces) of the wheel 31, spoke 32, and outer peripheral ring 33 forming the load support structure 39. 41b is being routed. Further, inside the load support structure 39, a loop-shaped conductive wire 41c is arranged. That is, the conductive wires 41a, 41b, and 41c are arranged in the load supporting structure 39 in the direction parallel to the side surface of the tire so as to surround the center of rotation of the tire. Then, the conductive wires 41a, 41b, and 41c are connected to form a loop-shaped coil having three circumferences. This is referred to as coil L2. That is, the coil L2 is a coil provided in the secondary resonance circuit 21 shown in FIG.

The coil L2 and the capacitor C2 are electrically connected to form the secondary resonant circuit 21 shown in FIG.
When the surface or side surface of the tire 30 is deteriorated or damaged, the capacitance of the capacitor C2 or the inductance of the coil L2 changes. Hereinafter, a detailed description will be given.

When the capacitance of the capacitor C2 is indicated by the same reference numeral C2, when the electrode area is S, the distance between the electrodes is d, the relative permittivity of the dielectric between the electrodes is ε, and the dielectric constant of the vacuum is ε0, the capacitance is electrostatic. The capacitance C2 can be represented by the following equation (1).
C2 = ε ・ ε0 ・ (S / d)… (1)

That is, the capacitance C2 changes according to the electrode area S. Therefore, if the area or conductivity of the fiber reinforced layer 36 changes due to deterioration or damage to the surface of the tire 30, the capacitance C2 will change.

On the other hand, when the side surface of the tire 30 is deteriorated or damaged, any of the conductive wires 41a, 41b, and 41c is damaged due to this, and the inductance of the coil L2 changes. That is, when the surface or side surface of the tire 30 is deteriorated or damaged, the impedance of the secondary resonance circuit 21 including the capacitor C2 and the coil L2 changes. As will be described later, in the present embodiment, the abnormality of the tire 30 is detected based on the change in the impedance of the secondary resonance circuit 21.

FIG. 7 is an equivalent circuit diagram of the primary resonance circuit 11 and the secondary resonance circuit 21. As shown in FIG. 7, the secondary resonance circuit 21 is configured as a series connection circuit of the capacitor C2, the coil L2, and the resistor R2.

On the other hand, the primary resonance circuit 11 is configured as a series connection circuit of the capacitor C1 and the coil L1 and is connected to the AC signal generation circuit 12. Then, as shown in FIG. 6, the coils L2 are arranged close to the coil L1 and opposed to each other, and are electromagnetically coupled.

Further, the numerical value of each element is set so that the resonance frequency of the primary resonance circuit 11 and the resonance frequency of the secondary resonance circuit 21 match. That is, the capacitance of the capacitor C2 composed of the conductor layer 34 and the fiber reinforcing layer 36 described above and the inductance of the coil L2 composed of the conductive wires 41a, 41b, and 41c arranged in a loop are known. Therefore, the capacitance of the capacitor C1 of the primary resonance circuit 11 and the inductance of the coil L1 are set so as to match these resonance frequencies.
Therefore, when an AC signal having a resonance frequency is output by the AC signal generation circuit 12 and a current flows through the primary resonance circuit 11, a current flows through the secondary resonance circuit 21 due to electromagnetic field coupling.

Next, the operation of the present embodiment configured as described above will be described. As described above, the resonance frequency of the primary resonance circuit 11 and the resonance frequency of the secondary resonance circuit 21 are the same, and when the AC signal of this resonance frequency is output from the AC signal generation circuit 12, the coils L1 and L2 Since it is electromagnetically coupled, a current flows through the primary resonance circuit 11 and the secondary resonance circuit 21. The current flowing through the primary resonance circuit 11 when the tire 30 is not damaged is defined as the "reference current".

When the surface or side surface of the tire 30 is damaged, the capacitance of the capacitor C2 or the inductance of the coil L2 changes, and the impedance of the secondary resonant circuit changes. Therefore, the current flowing through the primary resonant circuit 11 changes.

The tire abnormality detection circuit 13 calculates the difference between the current detected by the primary resonance circuit 11 and the above reference current, and if it is determined that the difference is larger than the preset threshold value, the tire 30 fails. Is determined to have occurred. In other words, when the impedance of the secondary resonance circuit 21 changes, the current flowing through the primary resonance circuit 11 changes with the change in the impedance. When this change, that is, the difference from the reference current becomes equal to or greater than the threshold value, it is determined that the tire 30 has an abnormality such as cracks, cracks, or peeling.

That is, when the impedance of the secondary resonance circuit 21 changes, the abnormality of the tire 30 due to the change in impedance is transmitted to the primary resonance circuit 11 as an electric signal (or electromagnetic wave). That is, the electromagnetic field coupling between the primary resonance circuit 11 and the secondary resonance circuit 21 functions as a communication circuit. In this way, the abnormality that occurs in the tire 30 can be detected.

In this way, in the tire detection device according to the first embodiment, the capacitor C2 of the secondary resonance circuit 21 is formed by the conductor layer 34 and the fiber reinforcing layer 36. Therefore, when an abnormality occurs in the tire 30 and the capacitance of the capacitor C2 changes, the impedance of the secondary resonance circuit 21 changes. Then, since the abnormality of the tire is detected based on this change in impedance, the abnormality occurring in the tire 30 can be detected with high accuracy regardless of whether the tire 30 is rotating (when the vehicle is running) or stopped (when the vehicle is stopped). Will be possible.

Further, the vehicle body side circuit 10 is provided with the primary resonance circuit 11 which is electromagnetically coupled to the secondary resonance circuit 21, and the change in the current flowing through the primary resonance circuit 11 is detected to detect the abnormality of the tire 30, so that the abnormality of the tire 30 is detected. Can be detected with high accuracy.

Further, since the abnormality of at least one of the capacitor C2 and the coil L2 is detected based on the change in the impedance of the secondary resonance circuit 21, it is possible to detect deterioration and damage occurring on the surface or side surface of the tire 30. It becomes.

Further, since the resonance frequencies of the primary resonance circuit 11 and the secondary resonance circuit 21 are matched and the AC signal of this resonance frequency is output from the AC signal generation circuit 12, the secondary resonance circuit 21 generated due to the abnormality of the tire 30. The change in current and voltage due to the change in impedance of the above becomes large, and the accuracy of abnormality detection can be improved.

Further, since the capacitor C2 of the secondary resonance circuit 21 is formed by the conductive fiber reinforcing layer 36 and the conductor layer 34 provided on the outer peripheral surface of the load support structure 39, the capacitor C2 can be easily formed. Furthermore, it is possible to detect abnormalities such as cracks, peeling, and cracks that occur on all the outer peripheral surfaces of the tire 30.

Further, the end of the electric wire of the fiber reinforced layer 36 is connected to the end side of the tire contact patch of the fiber reinforced layer 36 by an annular conductor 40 arranged along the circumferential direction of the tire. That is, in the conductive electric wire in the fiber reinforced layer 36 which is usually coated with an insulator, the conductor ends where the conductor portion is exposed are continuously connected by the annular conductor 40, so that the electrode area of the capacitor C2 Increases. Therefore, the conductivity of the fiber reinforced layer 36 can be made uniform, and a stable impedance change can be generated against damage and deterioration occurring on the surface over the entire circumference of the tire 30.

Further, the conductive wires 41a, 41b, and 41c are arranged in the load support structure 39 so as to surround the center of rotation of the tire 30 in the direction parallel to the side surface of the tire 30 to form the coil of the secondary resonance circuit 21. If any part of the load-bearing structure 39 is damaged, the conductivity will be damaged. Therefore, it is possible to detect an abnormality occurring on the side surface of the tire 30 as soon as possible at the stage of minor and local damage.

Further, by arranging conductive wires on both side surfaces of the load support structure 39, the coil of the secondary resonance circuit 21 can be easily configured. Generally, the stress concentration of the load bearing structure 39 made of a uniform material occurs on the surface of the structure. Therefore, it is known that fatigue fracture of the load bearing structure 39 usually occurs from the surface. By arranging conductive wires on both sides of the load-bearing structure 39, fatigue fracture generated from the surface of the structure can be detected without omission at the stage of local and minor fracture.

On the other hand, if voids or foreign matter are present inside the structure and the load supporting structure 39 is not made of a uniform material, the load supporting structure 39 may be destroyed from the inside. By arranging conductive wires inside the structure, even if fatigue fracture occurs from the inside, it is possible to detect it at the stage of local and minor fracture.

Further, in the above-described embodiment, an example of detecting an abnormality of the tire 30 based on the current flowing through the primary resonance circuit 11 has been described, but the present invention is not limited to this, and the voltage generated in the primary resonance circuit 11 is not limited to this. It is also possible to detect an abnormality in the tire 30 by detecting a change in the tire 30.

Further, in the above-described embodiment, an example of detecting an abnormality of a tire mounted on a vehicle has been described, but the present invention is not limited to this, and can be applied to other tires as well. ..

Further, the tire is not limited to the non-pneumatic tire, and can be adopted for the pneumatic tire. Further, in the present embodiment, the tire having the spokes 32 in the load support structure 39 has been described as an example, but a honeycomb structure or a load support structure having another structure may be applied.

[Explanation of the second embodiment]
Next, a second embodiment of the tire abnormality detection device according to the present invention will be described. FIG. 8 is a block diagram showing a configuration of a tire abnormality detection device according to a second embodiment. As shown in FIG. 8, the tire abnormality detection device according to the second embodiment includes a vehicle body side circuit 10a and a tire side circuit 20a.

The vehicle body side circuit 10a includes a tire abnormality notification circuit 15. On the other hand, the tire side circuit 20a includes a secondary resonance circuit 21, a tire abnormality detection circuit 22, and an AC signal generation circuit 23. Since the secondary resonance circuit 21 is the same as FIG. 1 shown in the first embodiment described above, the description of the configuration will be omitted. The AC signal generation circuit 23 supplies an AC signal to the secondary resonance circuit 21.
Further, a communication circuit 51 for communicating a signal between the vehicle body side circuit 10a and the tire side circuit 20a is provided.

The tire abnormality detection circuit 22 sets the current flowing through the secondary resonance circuit 21 as a reference current when the tire 30 is not deteriorated or damaged. Then, when the failure of the tire 30 is detected, the current flowing through the secondary resonance circuit 21 is detected, and when the difference between the detected current and the reference current exceeds a predetermined threshold value, an abnormality occurs in the tire 30. Judge that there is. Then, the abnormality occurrence signal is output.

As the communication circuit 51, a method of transmitting using electromagnetic waves or light, or a method of transmitting by wire via a slip ring can be used. It is also possible to use optical transmission using a light source such as an LED and an optical fiber.

The tire abnormality notification circuit 15 indicates that an abnormality has occurred in the tire 30 by, for example, issuing an alarm signal when an abnormality in the tire 30 is detected by the tire abnormality detection circuit 22 and the abnormality detection signal is received. Notify vehicle occupants, workers, etc.

Next, the operation of the tire abnormality detection device according to the second embodiment will be described. When an AC signal having a resonance frequency of the secondary resonance circuit 21 is output from the AC signal generation circuit 12 shown in FIG. 8, a current flows through the secondary resonance circuit 21. The current flowing through the secondary resonance circuit 21 when the tire 30 is not damaged is defined as the "reference current".

When the surface or side surface of the tire 30 is damaged, the capacitance of the capacitor C2 or the inductance of the coil L2 changes, and the impedance of the secondary resonance circuit 21 changes. Therefore, the current flowing through the secondary resonant circuit 21 changes.

The tire abnormality detection circuit 22 calculates the difference between the current detected by the secondary resonance circuit 21 and the above reference current, and when it is determined that the difference is larger than the preset threshold value, the tire 30 is used. Judge that a failure has occurred. In other words, when the impedance of the secondary resonance circuit 21 changes, the current flowing through the secondary resonance circuit 21 changes. Therefore, when this change, that is, the difference from the reference current becomes equal to or greater than the threshold value, It is determined that the tire 30 has an abnormality such as a crack, a crack, or a peeling.

When a tire abnormality is detected, the detected tire abnormality is transmitted to the tire abnormality notification circuit 15 of the vehicle body side circuit 10a by an electric signal or an electromagnetic wave via the communication circuit 51. As a result, it is possible to notify the occupants, workers, and the like of the vehicle that an abnormality has occurred in the tire 30.

In this way, in the tire abnormality detection device according to the second embodiment, the secondary resonance circuit 21 and the AC signal generation circuit 23 are provided in the tire side circuit 20a, and the secondary resonance circuit 21 is provided with the secondary resonance circuit. It supplies an AC signal with a resonance frequency. Then, when an abnormality occurs in the tire 30, the impedance of the secondary resonance circuit 21 changes and the current flowing through the secondary resonance circuit 21 changes, so that the occurrence of the abnormality can be detected.

Further, in the second embodiment, the AC signal generation circuit 23 is provided in the tire side circuit 20a, and the tire side circuit 20a detects the abnormality of the tire 30, so that the number of parts provided in the vehicle body side circuit 10a can be reduced. It will be possible. Further, it is possible to detect an abnormality of the tire 30 even when the tire 30 is not rotating.

Although the tire abnormality detection method and the tire abnormality detection device of the present invention have been described above based on the illustrated embodiment, the present invention is not limited to this, and the configurations of each part have the same functions. It can be replaced with any configuration.

10, 10a Body side circuit 11 Primary resonance circuit 12 AC signal generation circuit 13 Tire abnormality detection circuit 15 Tire abnormality notification circuit 20, 20a Tire side circuit 21 Secondary resonance circuit 22 Tire abnormality detection circuit 23 AC signal generation circuit 30 Non-pneumatic type Tire 31 Wheel 32 Spoke 33 Outer ring 34 Conductive layer 35 Coated rubber 36 Fiber reinforcement layer 37 Tread part 38 Outer rubber part 39 Load support structure 40 Circular conductor 41a Conductive wire 41b Conductive wire 41c Conductive wire 51 Communication circuit

Claims (10)

It is a tire abnormality detection method that has a secondary resonance circuit provided on the tire side and detects a tire abnormality based on a change in impedance of the secondary resonance circuit.
A capacitor of the secondary resonant circuit is formed by using a fiber reinforcing layer for increasing the strength of the tire and electrodes arranged on at least one of the load-bearing structures that support the tire.
A tire abnormality detection method characterized in that a detected tire abnormality is transmitted to the vehicle body side by an electric signal or an electromagnetic wave. In the method for detecting an abnormality in a tire according to claim 1,
A method for detecting an abnormality in a tire, which comprises supplying an AC signal to the secondary resonant circuit and detecting a change in impedance of the secondary resonant circuit based on a current or voltage generated in the secondary resonant circuit. The method for detecting an abnormality in a tire according to claim 1.
An AC signal is supplied to the primary resonant circuit provided on the vehicle body side and electromagnetically coupled to the secondary resonant circuit, and the impedance change of the secondary resonant circuit is changed based on the current or voltage generated in the primary resonant circuit. A tire abnormality detection method characterized by detection. In the method for detecting an abnormality in a tire according to claim 3,
A method for detecting an abnormality in a tire, characterized in that the resonance frequencies of the primary resonance circuit and the secondary resonance circuit are matched, and the AC signal is an AC signal of the resonance frequency. In the method for detecting an abnormality in a tire according to any one of claims 1 to 4.
A method for detecting an abnormality in a tire, which comprises detecting a change in impedance of the secondary resonance circuit based on a change in at least one of the capacitance of the capacitor of the secondary resonance circuit and the inductance of the coil. .. In the method for detecting a tire abnormality according to any one of claims 1 to 5,
A method for detecting an abnormality in a tire, wherein the capacitor of the secondary resonance circuit is composed of the fiber reinforcing layer and a conductor layer formed on the outer peripheral surface of the load supporting structure. The method for detecting an abnormality in a tire according to any one of claims 1 to 6.
A method for detecting an abnormality in a tire, wherein the fiber reinforcing layer is electrically connected to an end side of a ground contact surface of the tire by an annular conductor arranged along the circumferential direction of the tire. The method for detecting an abnormality in a tire according to any one of claims 1 to 7.
A tire abnormality characterized in that a conductive wire is arranged in the load support structure so as to surround the center of rotation of the tire in a direction parallel to the side surface of the tire to form a coil of the secondary resonance circuit. Detection method. In the method for detecting an abnormality in a tire according to claim 8,
A method for detecting an abnormality in a tire, wherein the coils of the secondary resonance circuit are provided on both side surfaces of the load support structure. A tire abnormality detection device having a secondary resonance circuit provided on the tire side and detecting a tire abnormality based on a change in impedance of the secondary resonance circuit.
A capacitor of the secondary resonant circuit is formed by using a fiber reinforcing layer for increasing the strength of the tire and electrodes arranged on at least one of the load-bearing structures that support the tire.
A tire abnormality detection device characterized by being equipped with a communication circuit that transmits detected tire abnormalities to the vehicle body side by electric signals or electromagnetic waves.

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