JP2023066796A - Tire abnormality determination system - Google Patents

Abstract

To determine whether an abnormality occurs in attachment of a tire or not.SOLUTION: A tire abnormality determination system comprises: an outside detector that detects acceleration in a rotating/circumferential direction of a tire outside of the vehicle in double tires, an inside detector that detects acceleration in the rotating/circumferential direction of the tire inside of the vehicle in the double tires, and a monitoring unit configured to be able to receive information from the outside detector and information from the inside detector. The monitoring unit, when magnitude of outside acceleration Gb detected by the outside detector deviates by a reference value ΔG0 or more from magnitude of inside acceleration Ga detected by the inside detector, determines that an abnormality occurs in attachment of the tire at the outside of the vehicle.SELECTED DRAWING: Figure 7

Description

TECHNICAL FIELD The present disclosure relates to a system for determining the presence or absence of a tire mounting abnormality.

Conventionally, there is a direct system as one of systems (TPMS: Tire Pressure Monitoring System) for monitoring the air pressure of tires. In this type of TPMS, a detector provided with a sensor such as a pressure sensor is installed directly on the side of the wheel on which the tire is attached. In addition, the vehicle body is equipped with an antenna and a receiver. When the sensor detection signal is transmitted from the wheel side detector, the detection signal is received by the receiver via the antenna, and the tire pressure is measured. detection is performed.

Some of these direct TPMS have an autolocation function that automatically determines which wheel the detector that transmits data is installed on (see, for example, Japanese Patent Application Laid-Open No. 2017-58280). ).

JP 2017-58280 A

A wheel with a tire attached is usually fastened to a hub with bolts and nuts. If a tire installation error (loosening of the bolts and nuts that fasten the wheels, etc.) occurs while the vehicle is running, it can cause vibration, etc. Therefore, in the event that a tire installation error occurs, it should be detected at an early stage. It is desirable to take measures such as notifying the user through

However, Japanese Patent Application Laid-Open No. 2017-58280 makes no specific reference to such problems and countermeasures therefor.

The present disclosure has been made to solve the above-described problems, and its purpose is to determine whether or not there is a tire mounting abnormality.

A tire abnormality determination system according to an aspect of the present disclosure includes a first detector that detects circumferential acceleration of a first tire that is not steered, and a second detector that detects circumferential acceleration of a second tire that is not steered. and a monitoring unit configured to receive information from the first detector and the second detector. The monitoring unit determines that the first tire is abnormally mounted when the magnitude of acceleration detected by the first detector deviates from the magnitude of acceleration detected by the second detector by a reference value or more. .

According to the above aspect, when the two non-steering tires are mounted normally, the magnitude of the acceleration in the circumferential direction of rotation of those tires is approximately the same. If the magnitude of the acceleration in the circumferential direction of rotation deviates by a reference value or more, it is determined that one of the tires (first tire) is abnormally mounted. Accordingly, it is possible to determine whether or not there is an abnormality in the mounting of the tire.

Advantageous Effects of Invention According to the present disclosure, it is possible to determine whether or not there is a tire mounting abnormality.

1 is a diagram (1) schematically showing the configuration of a vehicle; FIG. It is a block diagram which shows the structure of a detector. FIG. 4 is a diagram for explaining directions in which an acceleration sensor detects acceleration; It is an exploded perspective view of a double tire. FIG. 4 is a diagram showing an example of inner acceleration Ga and outer acceleration Gb when no tire mounting abnormality has occurred; FIG. 4 is a diagram showing an example of inner acceleration Ga and outer acceleration Gb when a tire mounting error occurs. FIG. 11 is a flowchart (part 1) showing an example of a processing procedure of a monitoring unit; FIG. FIG. 2 is a diagram (part 2) schematically showing the configuration of the vehicle; FIG. 11 is a flowchart (part 2) showing an example of a processing procedure of the monitoring unit; FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

<Overall composition>
FIG. 1 is a diagram schematically showing the configuration of a vehicle 10 to which a tire abnormality determination system according to this embodiment is applied.

Vehicle 10 according to the present embodiment is a vehicle that has single tires on the front wheels that are steered and double tires on the rear wheels that are not steered. A single tire is a form in which one tire is mounted at one tire mounting position. A double tire is a form in which two tires of the same size connected to each other are mounted at one tire mounting position. Double tires are mainly used for large vehicles such as trucks and buses.

Furthermore, in vehicle 10 according to the present embodiment, two-axle double tires are employed for the rear wheels. Specifically, the vehicle 10 includes front tires 11 and 12 and rear double tires 21-24.

FIG. 1 illustrates a case where the vehicle 10 is a rear-wheel drive system. The rear double tires 21, 22, 23, and 24 are respectively attached to the left axle R1 of the first rear row, the right axle R2 of the first rear row, the left axle R3 of the second rear row, and the second rear row. It is mounted on axle R4 on the right side of the eye. The driving system of the vehicle 10 is not limited to the rear-wheel drive system, and may be a front-wheel drive system or an all-wheel drive system.

The double tire 21 includes a tire 21a on the inner side of the vehicle and a tire 21b on the outer side of the vehicle. The double tire 22 includes a tire 22a on the inner side of the vehicle and a tire 22b on the outer side of the vehicle. The double tire 23 includes a tire 23a on the inner side of the vehicle and a tire 23b on the outer side of the vehicle. The double tire 24 includes a tire 24a on the inner side of the vehicle and a tire 24b on the outer side of the vehicle.

Furthermore, the vehicle 10 is equipped with a system (TPMS) for monitoring the air pressure of each tire. Specifically, vehicle 10 includes a plurality of detectors 13 , 14 , 31 a - 34 b each detecting tire pressure, and TPMS receiver 40 . Detectors 13 and 14 are installed on wheels of front tires 11 and 12, respectively. The detectors 31a-34b are installed on the wheels of the rear tires 21a-24b, respectively. Each detector 13, 14, 31a-34b may be formed integrally with a valve for sucking air into each tire, for example.

Each detector 13, 14, 31a to 34b is activated when a predetermined activation condition is satisfied, detects the air pressure of each tire, and includes a detection result in a UHF (Ultra High Frequency) band radio signal (hereinafter simply referred to as (also referred to as "UHF signal"). It should be noted that the "predetermined activation condition" is set in advance so as to be satisfied regularly or irregularly. Thereby, the detectors 31 to 34 can be intermittently activated at mutually different timings.

The UHF signals output by the detectors 13, 14, 31a-34b include information indicating tire air pressure and at least information indicating a unique ID number for identifying each detector 13, 14, 31a-34b. is included. The TPMS receiver 40 can monitor the air pressure of each tire by receiving the UHF signal output from each detector 13, 14, 31a-34b.

The front tires 11 and 12 and the rear tires 21a to 24b have the same specification and configuration so that tire rotation can be performed. Therefore, the detectors 13, 14, 31a-34b have the same configuration. In the following description, the detectors 13, 14, 31a-34b are also referred to as "detector 30" without distinguishing between them, unless it is necessary to distinguish between them.

The TPMS receiver 40 is provided on the vehicle body side of the vehicle 10 . The TPMS receiver 40 comprises an antenna A 1 and a monitoring unit 45 . Antenna A1 is configured to be able to receive UHF signals transmitted from each detector 30 . A monitoring unit 45 monitors the air pressure of each tire based on the UHF signal received by antenna A1. The monitoring unit 45 includes a storage section 46 and a processing section 47 .

The processing unit 47 includes a processor such as a CPU (Central Processing Unit) (not shown), a memory, and an input/output buffer. The memory includes ROM (Read Only Memory) and RAM (Random Access Memory). The processor expands a program stored in ROM into RAM and executes it. Various processes executed by the processing unit 47 are described in the programs stored in the ROM.

Information indicating the tire position where each detector 30 is arranged, information indicating the tire air pressure, etc. are stored in the storage unit 46 in association with the ID number of each detector 30 . In this embodiment, a total of 10 tire positions (front left, front right, rear 1st row left inside, rear 1st row left outside, rear 1st row right inside, rear 1st row right outside, rear 2) left inside row, second rear row left outside, second rear row right inside, and second rear row right outside) are set in advance, and the ID number of each detector 30 is associated with one of the tire positions. It is For example, the ID number of the detector 13 is associated with the tire position "front left", and the ID number of the detector 32a is associated with the tire position "rear first row right inside".

When the UHF signal is received from each detector 30, the monitoring unit 45 refers to the information stored in the storage unit 46 to specify the tire position of the ID number included in the UHF signal, and the specified tire position. is updated with the tire pressure contained in the UHF signal. For example, when the monitoring unit 45 receives a UHF signal containing the ID number of the detector 32a, the monitoring unit 45 refers to the corresponding relationship between the ID number and the tire position stored in the storage unit 46 to obtain the information contained in the UHF signal. The tire position corresponding to the ID number is identified as "first rear row, right inner side", and the air pressure of the identified "rear first row, right inner side" is updated with the tire pressure included in the UHF signal.

The TPMS receiver 40 can cause the display unit 60 to display the information on the correspondence relationship between tire positions and tire pressures stored in the storage unit 46 . The display unit 60 is arranged at a position that can be visually recognized by the driver. The display unit 60 is arranged, for example, on an in-vehicle instrument panel.

If the tire pressure included in the received UHF signal is equal to or less than the low pressure threshold, the monitoring unit 45 causes the display unit 60 to display a warning and the tire position where the tire pressure is equal to or less than the low pressure threshold. The TPMS receiver 40 performs this tire air pressure determination process for each received UHF signal, and monitors the air pressure of each tire. This allows the driver to recognize in real time the position of the tire that has fallen below the low pressure threshold.

<Configuration of detector 30>
FIG. 2 is a block diagram showing the configuration of the detector 30. As shown in FIG. The detector 30 includes a controller 35, a pressure sensor 38, an acceleration sensor (G sensor) 39, an antenna A2, and a transmission circuit CT.

The controller 35 includes a storage section 36 and a processing section 37 . The processing unit 37 includes a processor such as a CPU (not shown), a memory, and an input/output buffer. The memory includes ROM and RAM. The processor expands a program stored in ROM into RAM and executes it. Programs stored in the ROM describe various processes to be executed by the processing unit 37 .

A unique ID number is stored in the storage unit 36 for each detector 30 shown in FIG. For example, the storage unit 36 included in the detector 13 of FIG. 1 stores "01" as an ID number. In addition, "02" is stored as an ID number in the storage unit 36 included in the detector 14 of FIG. In this manner, the ID number unique to each detector 30 is stored in the storage section 36 in each detector 30 .

The pressure sensor 38 detects tire air pressure and outputs the detection result (hereinafter also referred to as “tire air pressure P”) to the controller 35 . The acceleration sensor 39 detects acceleration (force) acting on the detector 30 and outputs a detection result (hereinafter also referred to as “acceleration G”) to the controller 35 . In addition to pressure sensor 38 and acceleration sensor 39, detector 30 may further include a temperature sensor for detecting tire temperature.

The controller 35 controls the transmission circuit CT to output the UHF signal from the antenna A2. The UHF signal includes information indicating the acceleration G in addition to information indicating the ID number and the tire pressure P stored in the storage unit 36 .

As described above, the detector 30 is activated and outputs a UHF signal at the timing when a predetermined activation condition is satisfied. The detector 30 is provided with a battery (not shown) and operates on electric power supplied from the battery. Since this battery cannot be easily charged from the outside, the operating time of the detector 30 is minimized for detection. It is desirable to reduce the power consumption of the device 30 . From this point of view, the "predetermined activation condition" is set in advance so as to minimize the activation frequency of the detector 30 . For example, the predetermined activation conditions include a timer activation condition that a timer (not shown) measures that a predetermined timer time has elapsed since the previous stop, and acceleration G detected by the acceleration sensor 39 is a specific value (for example, maximum value or minimum value) may be included.

The "timer time" used in the above-described timer activation condition may be a fixed value, or may be a variable value that varies according to the acceleration G, for example. For example, the controller 35 determines whether the tires are rotating based on the acceleration G, which is the detection result of the acceleration sensor 39, and if the tires are not rotating and is in a stopped state, the timer time is relatively long. Set the time (for example, several minutes, or even longer several hours), and set the timer time to a relatively short time (for example, several seconds, or even shorter several millimeters) when the tires are rotating. seconds). Also, the time for one activation of the detector 30 (time from activation to next deactivation) may be limited to a relatively short time (for example, several milliseconds).

<Detection direction of acceleration sensor (G sensor) 39>
FIG. 3 is a diagram for explaining directions in which the acceleration sensor 39 detects acceleration. Note that FIG. 3 illustrates a configuration in which a valve for drawing air into the tire and the detector 30 are integrally formed.

The detector 30 is fixed to the wheel WH to which the tire is attached. The acceleration sensor 39 is a uniaxial acceleration sensor that detects acceleration in one direction. In this embodiment, the detector 30 is fixed to the wheel WH so that the direction in which acceleration is detected by the acceleration sensor 39 is the circumferential direction of rotation of the tire. That is, the acceleration sensor 39 detects the acceleration in the circumferential direction of rotation of the tire.

Note that the acceleration sensor 39 detects positive acceleration when the tire rotates in either clockwise or counterclockwise direction when viewed from the lateral direction (vehicle width direction). It is configured to detect the acceleration as a negative value when rotating and accelerating in the other direction.

<Double tire configuration>
Vehicle 10 according to the present embodiment has double tires 21 to 24 on the rear wheels, which are non-steering wheels, as described above.

4 is an exploded perspective view of the double tire 22. FIG. An example of the configuration of the double tire 22 will be described with reference to FIG. 4 . The other double tires 21, 23, and 24 also have the same configuration as the double tire 22. As shown in FIG.

The double tire 22 includes a vehicle inner tire (hereinafter also referred to as "inner tire") 22a and a vehicle outer tire (hereinafter also referred to as "outer tire") 22b. The tire 22a on the vehicle inner side is fixed to the axle R2 by passing the bolt BT of the hub H2 of the axle R2 through a hole provided in the flat portion FP of the wheel WH and tightening it with an inner nut NIN. A screw thread is formed on the tip side (vehicle outer side) of the inner nut NIN.

The outer tire 22b is fixed to the inner tire 22a by threading the screw thread on the tip side of the inner nut NIN through a hole provided in the flat portion FP of the wheel WH and fastening it with a wheel nut NW. As a result, the tire 22a and the tire 22b are connected to each other and connected to the axle R2.

The flat portion FP of each wheel WH protrudes outward from the side surface portion (sidewall portion) of each tire. The tires 22a and 22b are fixed with the flat portions FP of the wheels WH facing each other.

Detector 30 (detector 32a, detector 32b) according to the present embodiment detects acceleration as a positive value when the tire is rotated clockwise and accelerated when the tire is viewed from the flat portion FP side, It is fixed to each wheel WH so that the acceleration when it rotates counterclockwise and accelerates is detected as a negative value. Therefore, when the vehicle 10 accelerates forward, the detector 32a of the inner tire 22a detects a positive value of acceleration, while the detector 32b of the outer tire 22b detects negative acceleration of the same magnitude as the detector 32a. will be detected as the value of

In the following description, when the double tire 22 is viewed from the side, the detector 32a of the inner tire 22a and the detector 32b of the outer tire 22b are arranged at overlapping positions.

<Detection of abnormal tire installation>
If a tire installation error occurs while the vehicle is running, it can cause vibration, etc. Therefore, it is desirable to take measures such as detecting the tire installation error early and notifying the user. .

In particular, in the vehicle 10 equipped with double tires, even if the tire on the outer side of the vehicle is mounted abnormally, the user may not notice the abnormal mounting of the tire because the vehicle can run on the tire on the inner side of the vehicle. Therefore, it can be said that there is an even greater need for detecting a tire mounting abnormality in the vehicle 10 equipped with double tires.

Therefore, the monitoring unit 45 according to the present embodiment is configured to determine whether or not there is a tire mounting abnormality by the following method.

The inner tire 22a and the outer tire 22b of the double tire 22 are fixed to each other and rotate integrally. Therefore, the magnitude of the acceleration G detected by the acceleration sensor 39 installed on the inner tire 22a (hereinafter also simply referred to as "inner acceleration Ga") and the acceleration G detected by the acceleration sensor 39 installed on the outer tire 22b (hereinafter also simply referred to as "outer acceleration Gb") has substantially the same value.

FIG. 5 is a diagram showing an example of the magnitude of the inner acceleration Ga and the magnitude of the outer acceleration Gbn when there is no tire mounting error. When the vehicle 10 accelerates in the forward direction when there is no tire mounting error, the magnitude of the inner acceleration Ga and the magnitude of the outer acceleration Gb are approximately the same value.

On the other hand, if the outer tire 22b is attached abnormally due to improper fastening (looseness) of the wheel nut NW, etc., the inner tire 22a and the outer tire 22b will not rotate integrally. is a different value.

FIG. 6 is a diagram showing an example of the magnitude of the inner acceleration Ga and the outer acceleration Gb when the outer tire 22b is mounted abnormally. Note that FIG. 6 illustrates a state in which the outer tire is inclined at an angle θ with respect to the inner tire. In this case, the magnitude of the outer acceleration Gb is smaller than the magnitude of the inner acceleration Ga (=Ga·cos θ).

In view of this point, the monitoring unit according to the present embodiment detects the magnitude (absolute value) of the outer acceleration Gb detected by the detector 30 of the outer tire and the inner acceleration detected by the detector 30 of the inner tire. Ga is compared with the magnitude (absolute value) of Ga, and if the difference is greater than the reference value ΔG0, it is determined that the outer tire of the double tire is mounted abnormally.

FIG. 7 is a flow chart showing an example of a processing procedure when the monitoring unit 45 determines whether the tire is mounted abnormally.

The monitoring unit 45 acquires the outer acceleration Gb from the detector 30 (hereinafter also referred to as "outer detector 30b") arranged on the outer tire of the double tires (step S10).

Next, the monitoring unit 45 acquires the inner acceleration Ga from the detector 30 (hereinafter also referred to as "inner detector 30a") arranged on the inner tire of the double tires (step S12).

Next, the monitoring unit 45 determines whether or not the difference between the magnitude (absolute value) of the outer acceleration Gb and the magnitude (absolute value) of the inner acceleration Ga is greater than or equal to the reference value ΔG0 (step S14). If the difference is not greater than or equal to the reference value ΔG0 (NO in step S14), the monitoring unit 45 terminates the process.

If the difference is greater than or equal to the reference value ΔG0 (YES in step S14), the monitoring unit 45 determines that the outside tire of the double tire is mounted abnormally (step S16). At this time, the monitoring unit 45 may cause the display section 60 to display information about the tire determined to be mounting abnormally to notify the user.

As described above, the tire abnormality determination system according to the present embodiment includes the outer detector 30b that detects the circumferential acceleration of the outer tire of the dual tires, and the outer detector 30b that detects the circumferential acceleration of the inner tire of the double tires. It comprises an inner detector 30a and a monitoring unit 45 configured to receive information from the outer detector 30b and the inner detector 30a. When the magnitude of the outer acceleration Gb detected by the outer detector 30b deviates from the magnitude of the inner acceleration Ga detected by the inner detector 30a by a reference value ΔG0 or more, the monitoring unit 45 determines whether the outer tire is installed. Judged as abnormal.

According to such a configuration, it is possible to detect the mounting abnormality of the double tires, which is in great need of detection.

[Modification 1]
Each detector 30 described above is activated separately at the timing when each activation condition is satisfied, and outputs a UHF signal including information on the acceleration G. FIG. Therefore, it is conceivable that the timing at which the monitoring unit 45 acquires the outer acceleration Gb and the timing at which the inner acceleration Ga is acquired are greatly deviated. In this case, even if there is no tire mounting error, the magnitude of the outer acceleration Gb and the magnitude of the inner acceleration Ga may differ from each other due to changes in the longitudinal acceleration of the vehicle 10 due to the user's driving operation. .

Therefore, when the time interval between the timing at which the monitoring unit 45 acquires the outer acceleration Gb and the timing at which the inner acceleration Ga is acquired deviates by a predetermined time or longer, the tire mounting abnormality determination (the process of step S14 in FIG. 7) is performed. ) itself, and the acquired acceleration data may be discarded. As a result, it is possible to prevent an erroneous determination that a tire mounting abnormality has occurred even though the tire mounting abnormality has not actually occurred.

[Modification 2]
In the above-described embodiment, an initiator may be provided for activating each detector 30 .

FIG. 8 is a diagram schematically showing the configuration of a vehicle 10A according to Modification 2. As shown in FIG. Vehicle 10A is obtained by adding initiators 51, 52, 61, 62 for starting each detector 30 to vehicle 10 shown in FIG.

Each initiator 51 , 52 , 61 , 62 is electrically connected to the TPMS receiver 40 . The initiator 51 is arranged near the front left tire 11 and used to activate the detector 13 . The initiator 52 is arranged near the front right tire 12 and used to activate the detector 14 . The initiator 61 is arranged near the rear left double tires 21 and 23 and is used to activate the detectors 31a, 31b, 33a and 33b. The initiator 62 is arranged near the rear right double tires 22, 24 and is used to activate the detectors 32a, 32b, 34a, 34b.

Each initiator 51, 52, 61, 62 has the same configuration. In the following description, the initiators 51, 52, 61, and 62 are also referred to as the "initiator 50" without distinguishing between them when the initiators 51, 52, 61, and 62 need not be distinguished.

The initiator 50 includes an antenna (not shown), and is configured to be capable of outputting an LF (Low Frequency) band radio signal (hereinafter also simply referred to as an "LF signal") from the antenna. The initiator 50 transmits the LF signal based on instructions from the monitoring unit 45 .

Each detector 30 can receive the LF signal from the initiator 50 in a standby state. Each detector 30 is configured to start up and output a UHF signal when it receives an LF signal from the initiator 50 in the standby state, in addition to when the above-described predetermined start condition is satisfied.

In vehicle 10</b>A according to Modification 2, each detector 30 can be activated by initiator 50 . In view of this point, the monitoring unit 45 according to Modification 2 determines the tire mounting abnormality in two steps. Specifically, the monitoring unit 45 first determines whether there is a possibility of a tire mounting error based on the acceleration G output by the detectors 30 themselves. When it is determined that there is a possibility of a tire mounting abnormality, the monitoring unit 45 causes the initiator 50 to forcibly activate each detector 30 to measure and output the acceleration G in a shorter cycle. A request is made to the detector 30, and the presence or absence of tire mounting abnormality is determined based on the acceleration G detected in a short period.

FIG. 9 is a flow chart showing an example of a processing procedure when the monitoring unit 45 according to Modification 2 determines whether the tire is mounted abnormally. The flowchart of FIG. 9 is obtained by adding steps S20 to S26 to the flowchart of FIG. 7 described above, and changing step S14 of the flowchart of FIG. 7 described above to step S14A.

The monitoring unit 45 acquires the outer acceleration Gb from the outer detector 30b of the double tire (step S10), and acquires the inner acceleration Ga from the inner detector 30a (step S12). In steps S10 and S12, it is assumed that each of outer detector 30b and inner detector 30a separately measures and outputs acceleration G in a relatively long first cycle (for example, several minutes).

Next, the monitoring unit 45 determines whether there is a possibility of an outside tire mounting abnormality based on the outside acceleration Gb and the inside acceleration Ga acquired in steps S10 and S12 (step S20). For example, when the difference between the magnitude of the outer acceleration Gb and the magnitude of the inner acceleration Ga is equal to or greater than the reference value ΔG0, the monitoring unit 45 determines that there is a possibility that the outer tire is mounted abnormally. If it is not determined that there is a possibility of tire mounting abnormality (NO in step S20), monitoring unit 45 skips subsequent processing.

On the other hand, when it is determined that there is a possibility of tire mounting abnormality (YES in step S20), monitoring unit 45 causes initiator 50 to output an LF signal including a short-cycle measurement request signal. The short-period measurement request signal is a signal for forcibly activating each detector 30 to request each detector 30 to measure and output the acceleration G in a shorter period.

When each detector 30 receives the short-cycle measurement request signal in the standby state, each detector 30 has a second cycle (for example, several milliseconds) that is shorter than the first cycle (for example, several minutes) before receiving the short-cycle measurement request signal. to measure and output acceleration.

Next, the monitoring unit 45 acquires the outer acceleration Gb detected by the outer detector 30b in the short second period (step S24), and acquires the inner acceleration Ga detected by the inner detector 30a in the short second period. (step S26).

Next, the monitoring unit 45 determines whether or not the difference between the magnitude of the outer acceleration Gb acquired in step S24 and the magnitude of the inner acceleration Ga acquired in step S26 is greater than or equal to the reference value ΔG0 (step S14A). . If the difference is not greater than or equal to the reference value ΔG0 (NO in step S14A), monitoring unit 45 ends the process.

If the difference is greater than or equal to the reference value ΔG0 (YES in step S14A), the monitoring unit 45 determines that the outer tire of the double tire is mounted abnormally (step S16).

As described above, the initiator 50 for activating each detector 30 is provided, and the initiator 50 forcibly activates each detector 30 when it is determined that there is a possibility of a tire mounting abnormality. Alternatively, the acceleration G may be measured in a shorter cycle. As a result, it is possible to accurately determine the tire mounting abnormality while suppressing the power consumption of each detector 30 as much as possible.

[Modification 3]
In the above-described embodiment, the outer tire of the double tires is used as a determination target for mounting abnormality, and the inner tire is used as a comparison target. An example of determination has been described.

However, the tires to be determined and the tires to be compared may be non-steering tires, and are not necessarily limited to the outer and inner tires of the double tires.

For example, in the vehicle 10, when the eight non-steered rear tires 21a to 24b do not have a mounting abnormality, the magnitude of the acceleration in the circumferential direction of rotation of these tires is basically the same value. Become. Therefore, the tire to be determined and the tire to be compared may be arbitrarily selected from the eight rear tires 21a to 24b.

In addition, in a normal passenger car that does not have double tires, the left and right rear wheels that are not steered can be used as tires to be determined and tires to be compared.

[Modification 4]
In the above-described embodiment, an example has been described in which the inner tire detector 30 and the outer tire detector 30 are arranged so as to overlap when the double tires are viewed from the side.

However, in practice, it is conceivable that when the double tires are viewed from the side, the inner tire detector 30 and the outer tire detector 30 are not overlapped and are arranged at positions shifted by a predetermined angle. . In this case, the magnitude of the outer acceleration Gb and the magnitude of the inner acceleration Ga may have different values due to the influence of gravitational acceleration even if there is no tire mounting error.

As a countermeasure, for example, each detector 30 is added with a function of detecting acceleration in the radial direction of tire rotation, and each detector 30 grasps its own rotational angular position based on the acceleration in the radial direction of tire rotation, and detects in advance. Acceleration in the circumferential direction of the tire is output at a predetermined rotational angular position (e.g., 12 o'clock or 6 o'clock or both at which the acceleration in the circumferential direction of the tire does not include the effect of gravitational acceleration). It may be configured to By doing so, even if the arrangement angle of the detector 30 of the tire to be determined is deviated from the arrangement angle of the detector 30 of the tire to be compared, any predetermined arbitrary Accelerations in the circumferential direction of tire rotation at rotational angular positions can be compared. Therefore, it is possible to appropriately determine the presence or absence of tire mounting abnormality.

Further, when the initiator 50 described in the second modified example is provided, the initiator 50 forcibly activates each detector 30 to measure and output the acceleration G in a shorter cycle, so that the monitoring unit 45 The waveform of the acceleration G for one rotation of the tire may be grasped. By doing so, the monitoring unit 45 can compare the accelerations in the circumferential direction of the tire rotation at any predetermined rotation angle position, or compare the waveforms of the acceleration G with each other. Therefore, it is possible to appropriately determine the presence or absence of tire mounting abnormality.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

The exemplary embodiments and modifications thereof described above are specific examples of the following aspects.
(1) A tire abnormality determination system according to one aspect of the present disclosure includes a first detector that detects acceleration in the circumferential direction of rotation of a first tire that is not steered, and a detector that detects acceleration in the circumferential direction of rotation of a second tire that is not steered. 2 detectors and a monitoring unit configured to receive information from the first detector and the second detector. The monitoring unit determines that the first tire is abnormally mounted when the magnitude of the acceleration detected by the first detector deviates from the magnitude of the acceleration detected by the second detector by a reference value or more. .

According to the above aspect, in view of the fact that the magnitude of the acceleration in the circumferential direction of rotation of the two non-steered tires is approximately the same value, the magnitude of the acceleration in the circumferential direction of rotation of the two tires that are not steered deviates by a reference value or more. If so, it is determined that the first tire is improperly mounted. Accordingly, it is possible to determine whether or not there is an abnormality in the mounting of the tire.

(2) In one aspect, the first tire and the second tire are double tires that are arranged on the vehicle while being connected to each other.

According to the above aspect, it is possible to determine whether or not there is a mounting abnormality in the double tires that are mainly employed in large vehicles such as trucks and buses.

(3) In one aspect, the first tire is a tire that is positioned further outside the vehicle than the second tire.

According to the above aspect, it is possible to determine whether or not there is a mounting abnormality in the outer tire of the double tire.

(4) In one aspect, it further comprises an initiator that outputs a command signal to the first detector and the second detector. The first detector and the second detector periodically detect acceleration. The monitoring unit determines whether there is a possibility that a mounting abnormality has occurred based on the acceleration detected by the first detector and the acceleration detected by the second detector. When it is determined that there is a possibility, a request signal is output to the first detector and the second detector via the initiator. The first detector and the second detector detect acceleration in a second period shorter than the first period before receiving the request signal when receiving the request signal from the initiator. When the magnitude of the acceleration detected by the first detector in the second period deviates from the magnitude of the acceleration detected by the second detector in the second period by a reference value or more, the monitoring unit is determined to be abnormal.

According to the above aspect, the acceleration detection cycle by the first detector and the second detector can be suppressed to the relatively long first cycle until it is determined that there is a possibility that the mounting abnormality has occurred. . Therefore, the power consumption of the first detector and the second detector can be suppressed. On the other hand, if it is determined that there is a possibility that a mounting abnormality has occurred, the detection period of the acceleration by the first detector and the second detector is changed to a second period shorter than the first period, thereby monitoring the It is possible to suppress a large deviation between the timing at which the unit acquires the acceleration from the first detector and the timing at which the unit acquires the acceleration from the second detector. Accordingly, it is possible to accurately determine the tire mounting abnormality. As a result, the power consumption of the first detector and the second detector can be suppressed as much as possible, and the tire mounting abnormality can be accurately determined.

(5) In one aspect, the first detector detects the air pressure of the first tire in addition to the circumferential acceleration of the first tire. The second detector detects the air pressure of the second tire in addition to the circumferential acceleration of the second tire.

According to the above aspect, using the first detector and the second detector, it is possible to monitor the air pressure of the tire in addition to determining whether the tire is mounted abnormally.

10, 10A vehicle 11, 12, 21a-24b tires 13, 14, 31a-34b detectors 21-24 double tires 30a inner detector 30b outer detector 35 controller 36, 46 storage unit 37 , 47 processing unit, 38 pressure sensor, 39 acceleration sensor, 40 receiver, 45 monitoring unit, 51, 52, 61, 62 initiator, 60 display unit, A1, A2 antenna, CT transmission circuit, R1, R2, R3, R4 Axle, FP plane, H2 hub, NIN inner nut, NW wheel nut, WH wheel.

Claims (5)

a first detector that detects the acceleration in the circumferential direction of rotation of the first tire that is not steered;
a second detector that detects the acceleration in the circumferential direction of rotation of the second tire that is not steered;
a monitoring unit configured to receive information from the first detector and the second detector;
The monitoring unit detects a mounting error of the first tire when the magnitude of the acceleration detected by the first detector deviates from the magnitude of the acceleration detected by the second detector by a reference value or more. A tire abnormality determination system that determines that there is. 2. The tire abnormality determination system according to claim 1, wherein said first tire and said second tire are double tires arranged on a vehicle while being connected to each other. 3. The tire abnormality determination system according to claim 2, wherein the first tire is a tire arranged outside the vehicle relative to the second tire. Further comprising an initiator that outputs a command signal to the first detector and the second detector,
the first detector and the second detector periodically detect acceleration;
The monitoring unit is
determining whether there is a possibility that the mounting abnormality has occurred based on the acceleration detected by the first detector and the acceleration detected by the second detector;
outputting a request signal to the first detector and the second detector via the initiator when it is determined that there is a possibility that the mounting abnormality has occurred;
The first detector and the second detector detect acceleration in a second period shorter than a first period before receiving the request signal when receiving the request signal from the initiator,
The monitoring unit detects that the magnitude of the acceleration detected by the first detector in the second period deviates from the magnitude of the acceleration detected by the second detector in the second period by the reference value or more. 4. The tire abnormality determination system according to any one of claims 1 to 3, wherein the tire abnormality determination system determines that there is an installation abnormality of the first tire when the first tire is present. The first detector detects the air pressure of the first tire in addition to the acceleration in the circumferential direction of rotation of the first tire,
The tire abnormality determination system according to any one of claims 1 to 4, wherein the second detector detects the air pressure of the second tire in addition to the circumferential acceleration of the second tire.

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