JP2019001342A - Method and device for detecting abnormality of tire - Google Patents

Abstract

To provide a method and a device for detecting abnormality of a tire each enabling easy detection of abnormality of a tire.SOLUTION: A method for detecting abnormality of a tire includes a secondary resonance circuit 21 provided on a tire-side circuit 20 to detect abnormality of a tire 30 on the basis of variation in impedance of the secondary resonance circuit 21. A capacitor C2 is formed by using an electrode disposed on at least one of a fiber-reinforced layer 36 for enhancing strength of the tire 30 and a load support structure 39 supporting the tire 30. The detected abnormality of the tire 30 is transmitted to a vehicle body side circuit 10 with electric signals or electromagnetic waves.SELECTED DRAWING: Figure 1

Description

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

  As a method for detecting abnormalities such as cracks, cracks, peeling, and scratches generated in a tire, for example, a method disclosed in Patent Document 1 is known. In Patent Document 1, a magnetic body is provided on the surface of a tire at a predetermined pitch, and a magnet that forms an annular magnetic path is provided at an appropriate position on the vehicle body side at a position facing each magnetic body. And the change of the magnetic flux density which arises in an annular magnetic path with rotation of a tire is detected, and abnormality of a tire is detected based on the change of magnetic flux density.

Japanese Patent No. 4198414

  However, since the conventional example disclosed in Patent Document 1 described above detects a tire abnormality based on a change in magnetic flux density, it is an essential 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 abnormality detection device that can easily detect abnormality of a tire. It is to provide.

  In order to achieve the above object, the present invention is a tire abnormality detection method that includes a secondary resonance circuit provided on a tire side and detects an abnormality of a tire based on a change in impedance of the secondary resonance circuit. A capacitor of the secondary resonance circuit is formed by using an electrode disposed on at least one of the fiber reinforcement layer of the tire and the load support structure, and the detected abnormality of the tire is transmitted to the vehicle body side by an electric signal or electromagnetic wave.

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

FIG. 1 is a block diagram illustrating a configuration of a tire abnormality detection apparatus according to a first embodiment of the present invention. FIG. 2A is a cross-sectional view in a side surface direction of a non-pneumatic tire. 2B is an enlarged view of the “α” portion shown in FIG. 2A. FIG. 3 is a partially broken perspective view of a non-pneumatic tire. FIG. 4 is a perspective view showing a state in which a fiber reinforcing layer is provided on the outer periphery of the coat rubber. FIG. 5 is a perspective view showing a state in which a coil of a secondary resonance circuit is formed by providing a conductive wire on the side surface of the load support structure. FIG. 6 is an explanatory diagram showing a state in which 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 apparatus according to the 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 illustrating a configuration of a tire abnormality detection apparatus 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. 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 that flows through the primary resonance circuit 11, A tire abnormality detection circuit 13 that detects abnormalities such as cracks, cracks, and peeling that occur in the tire based on a change in current or voltage is provided.

  2A is a side sectional view of a non-pneumatic tire 30 (hereinafter abbreviated as “tire 30”) to be subjected to abnormality detection, FIG. 2B is an enlarged view of the “α” portion shown in FIG. 2A, and FIG. 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 shape in a side view at the center, and further provided with a load support structure 39 that supports the tire 30 around the wheel 31. The load support structure 39 has a plurality of spokes 32 (eight in the figure) provided from the wheel 31 toward the outer peripheral side, and a circular outer peripheral ring 33 provided at the tip of each spoke 32 in a side view. Yes. The outer ring 33 is made of, for example, a silicone resin, a urethane resin, an epoxy resin, or the like.

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 conductive material or a plate material.
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 coat rubber 35 in contact with the conductor layer 34, a fiber reinforcing layer 36 formed on the outer peripheral portion of the coat rubber 35, and a tread portion 37 formed on the outer peripheral portion of the fiber reinforcing layer 36. ing.

The fiber reinforcement layer 36 is a layer that improves 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 coat rubber 35. Each electric wire forming the fiber reinforcing layer 36 is covered, and the covering is peeled off at the side portion of the tire 30. In this embodiment, the annular conductor 40 is routed so as to go around the end portion of the fiber reinforcement layer 36, and the electric wires forming the fiber reinforcement layer 36 are electrically connected.

  With the above configuration, the conductive layer 34 having conductivity and the fiber reinforcing layer 36 having conductivity are disposed opposite to each other with the coat rubber 35 interposed therebetween, so that the capacitor functions as a capacitor having capacitance. This is 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.

  FIG. 5 is an explanatory diagram showing conductive wires arranged in the load support structure 39 of the tire 30. In FIG. 5, illustration 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, a conductive wire 41 a that forms a loop along one side surface and the other side surface (that is, both side surfaces) of the wheel 31, the spoke 32, and the outer peripheral ring 33 that form the load support structure 39. 41b is routed. Further, a conductive wire 41 c having a loop shape is routed inside the load support structure 39. That is, the conductive wires 41a, 41b, and 41c are routed on the load support structure 39 so as to surround the rotation center of the tire in a direction parallel to the side surface of the tire. The conductive wires 41a, 41b and 41c are connected to form a three-loop loop coil. This is referred to as a 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 constitute the secondary resonance 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. Details will be described below.

When the capacitance of the capacitor C2 is denoted by the same symbol C2, when the electrode area is S, the distance between the electrodes is d, the relative dielectric constant of the dielectric between the electrodes is ε, and the dielectric constant of the vacuum is ε0, The capacity C2 can be expressed by the following equation (1).
C2 = ε · ε0 · (S / d) (1)

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

  On the other hand, when the side surface of the tire 30 deteriorates or is 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 deteriorates or is 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, an abnormality of the tire 30 is detected based on a change in impedance of the secondary resonance circuit 21.

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

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

In addition, the numerical values of the respective elements are set so that the resonance frequency of the primary resonance circuit 11 and the resonance frequency of the secondary resonance circuit 21 coincide. That is, the capacitance of the capacitor C2 composed of the conductor layer 34 and the fiber reinforcement layer 36 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 coincide with these resonance frequencies.
Therefore, when an AC signal having a resonance frequency is output from 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 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 coincide with each other. When an AC signal having this resonance frequency is output from the AC signal generation circuit 12, the coils L1 and L2 are connected. Due to the electromagnetic coupling, a current flows through the primary resonance circuit 11 and the secondary resonance circuit 21. A current flowing through the primary resonance circuit 11 when the tire 30 is not damaged is referred to as a “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 changes. Accordingly, the current flowing through the primary resonance 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-described reference current, and if it is determined that the difference is greater than a preset threshold value, the tire 30 malfunctions. Is determined to have occurred. In other words, when the impedance of the secondary resonant circuit 21 changes, the current flowing through the primary resonant circuit 11 changes with the change in impedance. When the difference, that is, the difference from the reference current is equal to or greater than the threshold value, it is determined that an abnormality such as a crack, a crack, or a separation has occurred in the tire 30.

  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 coupling between the primary resonance circuit 11 and the secondary resonance circuit 21 functions as a communication circuit. Thus, an abnormality occurring in the tire 30 can be detected.

  Thus, 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 reinforcement 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. And since abnormality of a tire is detected based on this change in impedance, 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 when it is stopped (when the vehicle is stopped). Is possible.

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

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

  Further, the resonance frequencies of the primary resonance circuit 11 and the secondary resonance circuit 21 are made to coincide with each other, and an AC signal having this resonance frequency is output from the AC signal generation circuit 12, so that the secondary resonance circuit 21 generated due to the abnormality of the tire 30. The amount of change in current and voltage due to the impedance change becomes larger, and the abnormality detection accuracy 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, delaminations, and cracks that occur on all outer peripheral surfaces of the tire 30.

  Furthermore, the end of the electric wire of the fiber reinforcement layer 36 is connected to the end portion of the tire ground contact surface of the fiber reinforcement layer 36 by an annular conductor 40 disposed along the circumferential direction of the tire. That is, in the conductive wire in the fiber reinforcing layer 36 that is normally coated with an insulator, the conductor end portions where the conductor portions are exposed are continuously connected by the annular conductor 40, so that the electrode area of the capacitor C2 Will increase. Therefore, the electrical conductivity of the fiber reinforcement layer 36 can be made uniform, and a stable impedance change can be generated against damage and deterioration occurring on the surface over the circumference of the tire 30.

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

  Further, by arranging the conductive wires on both side surfaces of the load support structure 39, the coil of the secondary resonance circuit 21 can be easily configured. In general, the stress concentration of the load support structure 39 made of a uniform material occurs on the surface of the structure. Therefore, it is known that fatigue failure of the load support structure 39 usually occurs from the surface. By arranging the conductive wires on both surfaces of the load support structure 39, fatigue failure occurring from the surface of the structure can be detected without leakage at the stage of local and minor destruction.

  On the other hand, when there are voids or foreign matter inside the structure and the load support structure 39 is not made of a uniform material, the structure may be broken from the inside. By arranging a conductive wire inside the structure, even if a fatigue failure occurs from the inside, it can be detected at the stage of local and minor failure.

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

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

  Moreover, it is not limited to a non-pneumatic tire, It is possible to employ | adopt also about a pneumatic tire. In this embodiment, the tire having the spokes 32 in the load support structure 39 has been described as an example. However, a load support structure having a honeycomb structure or other structures may be applied.

[Description of 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 illustrating a configuration of a tire abnormality detection device according to the 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 10 a includes a tire abnormality notification circuit 15. On the other hand, the tire-side circuit 20 a 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 that shown in FIG. 1 shown in the first embodiment, the description of the configuration is omitted. The AC signal generation circuit 23 supplies an AC signal to the secondary resonance circuit 21.
Moreover, the communication circuit 51 which performs signal communication between the vehicle body side circuit 10a and the tire side circuit 20a is provided.

  The tire abnormality detection circuit 22 sets a current flowing through the secondary resonance circuit 21 as a reference current when the tire 30 is not deteriorated or damaged. 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, an abnormality occurs in the tire 30. Judge that there is. Then, an 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 light transmission using a light source such as an LED and an optical fiber.

  When the abnormality of the tire 30 is detected by the tire abnormality detection circuit 22 and the abnormality detection signal is received, the tire abnormality notification circuit 15 generates an alarm signal, for example, to indicate that the abnormality has occurred in the tire 30. Notify vehicle occupants and workers.

  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 illustrated in FIG. 8, a current flows through the secondary resonance circuit 21. A current flowing through the secondary resonance circuit 21 when the tire 30 is not damaged is referred to as a “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. Accordingly, the current flowing through the secondary resonance circuit 21 changes.

  The tire abnormality detection circuit 22 calculates the difference between the current detected by the secondary resonance circuit 21 and the reference current, and if it is determined that the difference is greater than a preset threshold value, the tire 30 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, so when this difference, that is, when the difference from the reference current is greater than or equal to the threshold value, It is determined that an abnormality such as a crack, a crack, or a peeling has occurred in the tire 30.

  If 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 via the communication circuit 51 by an electric signal or electromagnetic wave. As a result, it is possible to notify the vehicle occupant, worker, etc. that an abnormality has occurred in the tire 30.

  In this manner, 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 includes the secondary resonance circuit 21. An AC signal having a resonance frequency is supplied. 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.

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

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

DESCRIPTION OF SYMBOLS 10, 10a Car 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 Tire 31 Wheel 32 Spoke 33 Outer ring 34 Conductor layer 35 Coated rubber 36 Fiber reinforcement layer 37 Tread part 38 Outer rubber part 39 Load support structure 40 Annular conductor 41a Conductive line 41b Conductive line 41c Conductive line 51 Communication circuit

Claims (10)

A tire abnormality detection method comprising a secondary resonance circuit provided on a tire side, and detecting an abnormality of a tire based on a change in impedance of the secondary resonance circuit,
Forming a capacitor of the secondary resonance circuit by using a fiber reinforcing layer for increasing the strength of the tire and an electrode disposed on at least one of a load supporting structure for supporting the tire;
A method for detecting an abnormality of a tire, comprising transmitting the detected abnormality of the tire to the vehicle body side by an electric signal or an electromagnetic wave. In the tire abnormality detection method according to claim 1,
A tire abnormality detection method comprising: supplying an AC signal to the secondary resonance circuit; and detecting a change in impedance of the secondary resonance circuit based on a current or a voltage generated in the secondary resonance circuit. The tire abnormality detection method according to claim 1,
An AC signal is supplied to a primary resonance circuit that is provided on the vehicle body side and electromagnetically coupled to the secondary resonance circuit, and a change in impedance of the secondary resonance circuit is determined based on a current or voltage generated in the primary resonance circuit. A method for detecting an abnormality of a tire, characterized by detecting. In the tire abnormality detection method according to claim 3,
The tire abnormality detection method, wherein 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 tire abnormality detection method according to any one of claims 1 to 4,
A tire abnormality detection method, comprising: detecting a change in impedance of the secondary resonance circuit based on a change in at least one of a capacitance of a capacitor of the secondary resonance circuit and an inductance of a coil. . In the tire abnormality detection method according to any one of claims 1 to 5,
The tire abnormality detection method, wherein the capacitor of the secondary resonance circuit includes the fiber reinforcement layer and a conductor layer formed on an outer peripheral surface of the load support structure. A tire abnormality detection method according to any one of claims 1 to 6,
The tire abnormality detection method, wherein the fiber reinforcement layer is electrically connected to an end portion of the ground contact surface of the tire by an annular conductor disposed along a circumferential direction of the tire. A tire abnormality detection method according to any one of claims 1 to 7,
An abnormality in a tire characterized in that a conductive wire is routed in the load supporting structure so as to surround a rotation center of the tire in a direction parallel to a side surface of the tire to form a coil of the secondary resonance circuit. Detection method. In the tire abnormality detection method according to claim 8,
The tire abnormality detection method, wherein the coil of the secondary resonance circuit is provided on both side surfaces of the load support structure. A tire abnormality detection device that has a secondary resonance circuit provided on a tire side and detects an abnormality of a tire based on a change in impedance of the secondary resonance circuit,
Forming a capacitor of the secondary resonance circuit by using a fiber reinforcing layer for increasing the strength of the tire and an electrode disposed on at least one of a load supporting structure for supporting the tire;
A tire abnormality detection device comprising a communication circuit that transmits a detected tire abnormality to a vehicle body side by an electric signal or electromagnetic wave.

Images