WO2024116969A1 - Determination device - Google Patents

Determination device Download PDF

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Publication number
WO2024116969A1
WO2024116969A1 PCT/JP2023/041799 JP2023041799W WO2024116969A1 WO 2024116969 A1 WO2024116969 A1 WO 2024116969A1 JP 2023041799 W JP2023041799 W JP 2023041799W WO 2024116969 A1 WO2024116969 A1 WO 2024116969A1
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Prior art keywords
wheel
condition
frequency
determination process
elapsed
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PCT/JP2023/041799
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French (fr)
Japanese (ja)
Inventor
正則 小杉
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株式会社東海理化電機製作所
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Publication of WO2024116969A1 publication Critical patent/WO2024116969A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements

Definitions

  • This disclosure relates to a determination device that determines whether there are signs of a wheel coming off.
  • Patent Document 1 JP 2005-329907 A discloses a device that performs processing to determine whether there are signs of a wheel coming off (looseness of the nuts that attach the wheel to the vehicle body) based on the detection value of a detector attached to the wheel (tire or wheel).
  • the frequency with which the determination process is performed is generally fixed at a certain frequency. If the frequency with which the detection process is performed is fixed uniformly to a high value, the determination accuracy improves, but the load on the control unit that performs the determination process increases. On the other hand, if the frequency with which the determination process is performed is fixed uniformly to a low value, the load on the control unit can be reduced, but the determination accuracy decreases.
  • the present disclosure has been made to solve the above-mentioned problems, and its purpose is to reduce the load on the control unit that executes the determination process while maintaining the accuracy of the determination process for determining whether there are signs of wheel detachment.
  • the determination device includes a sensor unit that outputs a signal indicating the state of a wheel attached to a vehicle body, and a control unit that executes a determination process that determines whether there are signs of a wheel falling off based on the signal from the sensor unit. When a predetermined condition is met, the control unit executes the determination process more frequently than when the predetermined condition is not met.
  • the frequency with which the determination process is executed is not fixed to a constant frequency, but is switched depending on whether or not a specified condition is met. Specifically, when the specified condition is met, the frequency with which the determination process is executed is increased. This makes it possible to more accurately determine whether there are signs of a wheel falling off. On the other hand, when the specified condition is not met, the frequency with which the determination process is executed is not increased. This makes it possible to reduce the processing load on the control unit that executes the determination process. As a result, it is possible to reduce the processing load on the control unit while maintaining the accuracy of the determination made by the determination process.
  • FIG. 1 is a diagram illustrating a vehicle on which a determination device is mounted;
  • FIG. 2 is a diagram showing an example of a cross section of a nut on which a sensor device is disposed.
  • FIG. 2 is a diagram illustrating an example of a configuration of a sensor device.
  • FIG. 13 is a diagram showing the monthly occurrence number of wheel detachments.
  • FIG. 13 is a diagram showing the number of wheel detachment occurrences by period after the wheels are removed.
  • 11 is a flowchart (part 1) illustrating an example of a processing procedure of the sensor device.
  • 13 is a flowchart (part 2) illustrating an example of a processing procedure of the sensor device.
  • FIG. 1 is a schematic diagram of a vehicle 200 equipped with a determination device according to this embodiment.
  • the vehicle 200 includes a communication terminal 201, a button 202, an outside air temperature sensor 203, a control device 205, and a number of wheels 210.
  • Each of the multiple wheels 210 includes a wheel 220 and a tire 230 attached to the wheel 220.
  • each wheel 210 is attached to the body of the vehicle 200 (more specifically, the wheel hub 250a shown in FIG. 2) by five nuts 240. Note that the number of nuts 240 on each wheel 210 is not limited to five.
  • the sensor device 100 is disposed on one of the five nuts 240 that attach each wheel 210 to the vehicle body.
  • the sensor device 100 may be disposed on two or more of the five nuts 240 that attach each wheel 210 to the vehicle body.
  • the sensor device 100 according to this embodiment is an example of the "determination device" of the present disclosure.
  • FIG. 2 is a diagram showing an example of a cross section of a nut 240 in which the sensor device 100 is disposed. Note that FIG. 2 shows an example of a double tire. In a double tire, the wheel 220 is composed of an inner wheel 222 and an outer wheel 223.
  • the wheel 220 has a wheel hole 221.
  • a bolt 250 fixed to a wheel hub 250a is inserted (passes through) into the wheel hole 221.
  • the nut 240 fastens the bolt 250 inserted into the wheel hole 221 to the wheel 220.
  • a nut cap 241 is attached to the nut 240.
  • the nut cap 241 includes a ceiling portion 241a and a side portion 241b.
  • the side portion 241b is provided so as to circumferentially surround the portion of the bolt 250 that passes through the wheel hole 221.
  • the ceiling portion 241a is provided so as to face the tip portion 251 of the bolt 250 (in the direction in which the bolt 250 is inserted).
  • the ceiling portion 241a is provided continuously with the side portion 241b.
  • a washer 243 may be provided between the nut 240 and the wheel 220.
  • the sensor device 100 is attached (glued) to the inner surface 241c of the ceiling portion 241a of the nut cap 241. Therefore, the sensor device 100 is disposed in the space S of the nut cap 241 in which the bolt 250 is housed. Note that the sensor device 100 may be attached to the nut 240 itself, rather than to the nut cap 241.
  • the sensor device 100 is equipped with a sensor (e.g., an acceleration sensor) that outputs a signal indicating the mounting state of the wheel 210 relative to the vehicle body, and determines whether there are any signs of the wheel 210 falling off (looseness of the nut 240) based on the signal from the sensor.
  • a sensor e.g., an acceleration sensor
  • FIG. 3 is a diagram showing an example of the configuration of the sensor device 100.
  • FIG. 3 illustrates an example of the configuration in which the sensor device 100 uses an acceleration sensor to determine whether there are signs of the wheel 210 falling off (looseness of the nut 240).
  • the sensor used by the sensor device 100 to determine whether there are signs of the wheel 210 falling off is not necessarily limited to an acceleration sensor, and may be, for example, a magnetic sensor.
  • the sensor device 100 includes an acceleration sensor 1, a signal processing unit 2, a communication unit 3, and a power supply unit 4.
  • the acceleration sensor 1 detects, for example, the acceleration of each of two mutually orthogonal axes (X-axis and Y-axis) in a plane perpendicular to the rotation axis of the wheel 220.
  • the acceleration sensor 1 is an example of a "sensor unit" of the present disclosure.
  • the communication unit 3 is configured to be capable of wireless communication with the communication terminal 201 (see FIG. 1) of the vehicle 200.
  • the communication unit 3 transmits a signal indicating the processing result of the signal processing unit 2 to the communication terminal 201 (see FIG. 1) of the vehicle 200.
  • the communication unit 3 also receives information transmitted from the communication terminal 201 (see FIG. 1) of the vehicle 200 and transmits it to the signal processing unit 2.
  • the power supply unit 4 supplies power to each of the acceleration sensor 1, the signal processing unit 2, and the communication unit 3.
  • the power supply unit 4 can be realized, for example, by a button battery.
  • the signal processing unit 2 is configured to include a processor such as a CPU (not shown), a memory, and an input/output buffer. It executes a process (hereinafter also referred to as a "wheel-falling determination process") to determine whether the nut 240 is loose or not based on the signal from the acceleration sensor 1 (acceleration in the X-axis direction and acceleration in the Y-axis direction), determine whether there is a sign of the wheel 210 falling off based on the determination result, and transmit the determination result from the communication unit 3 to the communication terminal 201 of the vehicle 200.
  • a processor such as a CPU (not shown)
  • a memory such as a central processing unit
  • an input/output buffer input/output buffer
  • the signal processing unit 2 determines that the nut 240 is loose based on the signal from the acceleration sensor 1, it determines that there is a sign of the wheel 210 falling off, and transmits the determination result from the communication unit 3 to the communication terminal 201 of the vehicle 200. On the other hand, if the signal from the acceleration sensor 1 does not determine that the nut 240 is loose, it determines that there is no sign of the wheel 210 falling off, and transmits the determination result from the communication unit 3 to the communication terminal 201 of the vehicle 200.
  • the signal processing unit 2 is an example of a "control unit" in this disclosure.
  • the communication terminal 201 is configured to be capable of wireless communication with the sensor device 100 of each wheel 210.
  • the control device 205 includes a processor such as a CPU (Central Processing Unit) (not shown), a memory, and an input/output buffer.
  • the control device 205 monitors the state of the wheel 210 based on a signal received by the communication terminal 201 from the sensor device 100 of the wheel 210.
  • Button 202 is a button that is pressed by the user when the user performs the operation of attaching or detaching at least one wheel 210. When the user presses button 202, button 202 outputs a signal indicating that it has been pressed by the user to control device 205.
  • the outside air temperature sensor 203 detects the outside air temperature Tout and outputs a signal indicating the detection result to the control device 205.
  • the control device 205 transmits a signal indicating the outside air temperature Tout detected by the outside air temperature sensor 203 from the communication terminal 201 to the communication unit 3 of the sensor device 100 via wireless communication.
  • the control device 205 transmits a signal indicating that at least one wheel 210 has been detached (hereinafter also referred to as a "wheel detachment signal") from the communication terminal 201 to the communication unit 3 of the sensor device 100 via wireless communication.
  • a wheel detachment signal a signal indicating that at least one wheel 210 has been detached
  • the sensor device 100 is configured to switch the execution frequency F of the above-mentioned wheel-off determination process depending on whether a predetermined switching condition is met.
  • the occurrence of wheel detachment is related to the environmental temperature (outside temperature) at the time the wheel detaches and the period of time that has passed since the wheel was removed (the period from when the user removed the wheel to when the wheel detached).
  • Figure 4 shows the monthly number of wheel detachment incidents in Japan in recent years. As Figure 4 shows, wheel detachment incidents are concentrated in the cold months (winter) from November to February. From this situation, it can be inferred that wheel detachment is related to the environmental temperature at the time of occurrence, and more specifically, wheel detachment is more likely to occur when the outside temperature is low.
  • Figure 5 shows the number of wheel detachment incidents occurring in Japan in recent years, broken down by the period following wheel removal.
  • wheel detachment incidents are concentrated within a period of one to two months after the user removes the wheels. From this situation, it can be inferred that wheel detachment is related to the period that has passed since the wheels were removed, and more specifically, wheel detachment is likely to occur within a certain period (one to two months) after the wheels are removed.
  • the switching conditions for switching the execution frequency F of the wheel-off determination process include a "temperature condition” related to the outside air temperature (ambient temperature) and a "time-lapse condition” related to the period after the wheel 210 is detached.
  • the “temperature condition” is a condition in which the outside air temperature Tout is lower than a threshold temperature.
  • the threshold temperature is set to a value that makes it possible to determine whether or not it is the cold season (winter) when wheel detachment occurs most frequently.
  • the threshold temperature is set based on the average temperature when the season changes from autumn to winter, or the average temperature when the season changes from winter to spring.
  • the "elapsed condition” is a condition that the time T that has elapsed since the wheel 210 was removed is less than a threshold time.
  • the threshold time is set to a period of one to two months from the time the wheel was removed, during which time wheel detachment occurs most frequently.
  • the signal processing unit 2 of the sensor device 100 increases the frequency F of execution of the wheel runoff determination process compared to when neither the temperature condition nor the elapsed condition is met.
  • FIG. 6 is a flowchart showing an example of the processing procedure when the signal processing unit 2 of the sensor device 100 executes the wheel runoff determination process.
  • the signal processing unit 2 acquires the outside air temperature Tout (step S10).
  • the signal processing unit 2 can acquire the outside air temperature Tout by receiving the detection result of the outside air temperature sensor 203 from the communication terminal 201 of the vehicle 200. Note that if an outside air temperature sensor is provided in the sensor device 100, the detection result of the outside air temperature sensor in the sensor device 100 may be acquired as the outside air temperature Tout.
  • the signal processing unit 2 acquires the elapsed time T from the time the wheels were detached (step S20). For example, the signal processing unit 2 can count the elapsed time from the time the wheel detachment signal (a signal indicating that the wheel 210 has been detached) was received from the communication terminal 201 of the vehicle 200, and acquire the counted elapsed time as the elapsed time T from the time the wheels were detached.
  • the wheel detachment signal a signal indicating that the wheel 210 has been detached
  • the signal processing unit 2 is configured to be initialized when the output of the acceleration sensor 1 changes in a manner indicating wheel detachment, in view of the fact that the processing frequency (processing cycle) of the signal processing unit 2 after initialization is determined in advance, the number of times that the signal processing unit 2 executes the wheel detachment determination process or a predetermined process (for example, a process for measuring the output of the acceleration sensor 1 or a process for transmitting radio waves) after initialization may be counted, and the counted number of executions may be treated as the elapsed time T since the wheel detachment. In this way, the signal processing unit 2 of the sensor device 100 can independently determine the elapsed time T since the wheel detachment without communicating with the communication terminal 201 of the vehicle 200.
  • a predetermined process for example, a process for measuring the output of the acceleration sensor 1 or a process for transmitting radio waves
  • the signal processing unit 2 determines whether the outside air temperature Tout acquired in step S10 is lower than the above-mentioned threshold temperature (step S30). That is, in step S30, the signal processing unit 2 determines whether the above-mentioned air temperature condition is met.
  • the signal processing unit 2 also determines whether the elapsed time T from the time the wheel was attached or detached, which is acquired in step S20, is less than the above-mentioned threshold time (step S40). That is, in step S40, the signal processing unit 2 determines whether the above-mentioned elapsed condition is met.
  • the signal processing unit 2 sets the execution frequency F of the wheel-off determination process to the initial value F0 (step S60).
  • the signal processing unit 2 sets the execution frequency F of the wheel-off determination process to a predetermined value F2 that is higher than the initial value F0 (step S50). For example, if the initial value F0 is a frequency of once every 30 seconds, the predetermined value F2 is set to a frequency of once every 10 seconds.
  • the signal processing unit 2 executes the wheel runoff determination process at the execution frequency F set in step S50 or step S60 (step S70).
  • the signal processing unit 2 in this embodiment does not fix the execution frequency F of the wheel runoff determination process to a constant value, but switches it depending on whether the temperature conditions and elapsed conditions are met.
  • the signal processing unit 2 sets the execution frequency F of the wheel derailment determination process to a predetermined value F2, which is higher than the initial value F0. This makes it possible to accurately determine whether there are signs of wheel 210 falling off in a situation where there is a possibility of wheel derailment.
  • the signal processing unit 2 sets the execution frequency F of the wheel derailment determination process to an initial value F0, which is lower than the predetermined value F2. This makes it possible to reduce the processing load on the signal processing unit 2 in a situation where there is a low possibility of wheel derailment. As a result, it is possible to reduce the processing load on the signal processing unit 2 while maintaining the determination accuracy of the wheel derailment determination process.
  • the power required to operate the signal processing unit 2 is reduced compared to when the frequency F of execution of the wheel runoff determination process is fixed at a predetermined value F2, so the life of the power supply unit 4 (e.g., a button battery) can be extended.
  • the power supply unit 4 e.g., a button battery
  • the frequency F of execution of the wheel run-off determination process is set to the same value (predetermined value F2) regardless of whether both the temperature condition and the elapsed condition are met.
  • the frequency F of execution of the wheel runoff determination process is set to a higher value than when only one of the temperature condition and the elapsed time condition is met.
  • FIG. 7 is a flowchart showing an example of the processing procedure when the signal processing unit 2 of the sensor device 100 according to this modified example 1 executes the wheel runoff determination process.
  • the flowchart in FIG. 7 is the same as that in FIG. 6 above, except that steps S51 to S54 have been added instead of step S50.
  • the other steps in FIG. 7 (the steps having the same numbers as the steps shown in FIG. 6) have already been explained, so detailed explanations will not be repeated here.
  • the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to the initial value F0 (step S60).
  • the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to a predetermined value F1 that is higher than the initial value F0 (step S54). For example, if the initial value F0 is a frequency of once every 30 seconds, the predetermined value F1 is set to a frequency of once every 10 seconds.
  • the signal processing unit 2 determines whether the elapsed time T from when the wheels were removed is less than the threshold time (step S51).
  • the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to a predetermined value F2b (step S53).
  • the predetermined value F2b is set to a frequency equal to or greater than the predetermined value F1.
  • the predetermined value F1 is a frequency of once every 10 seconds
  • the predetermined value F2b is set to a frequency of once every 10 seconds, the same as the predetermined value F1, or to a frequency of once every 8 seconds, which is greater than the predetermined value F1.
  • the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to a predetermined value F2a (step S52).
  • the predetermined value F2a is set to a frequency higher than the predetermined value F2b. For example, if the predetermined value F2b is a frequency of once every 8 seconds, the predetermined value F2a is set to a frequency of once every 4 seconds.
  • the frequency F of execution of the wheel runoff detection process may be set to a higher value compared to when only one of the temperature condition and the elapsed condition is met. By doing so, it is possible to further improve the accuracy of the wheel runoff detection process while reducing the load on the signal processing unit 2.
  • the temperature condition is that the outside air temperature Tout is lower than a threshold temperature, but instead of or in addition to the condition that the outside air temperature Tout is lower than a threshold temperature, the temperature condition may be that the current period is a period in which the monthly average temperature is lower than a threshold temperature. Also, a condition that the area is cold may be added to the temperature condition.
  • the elapsed condition is that the elapsed time T from when the wheels were detached is less than a threshold time, but the elapsed condition may be that the number of times the wheel-off determination process has been executed since the wheels were detached is less than a threshold number of times.
  • the sensor device 100 arranged on the nut 240 of each wheel 210 performs the wheel derailment determination process, but the entity that performs the wheel derailment determination process is not necessarily limited to the sensor device 100 arranged on the nut 240 of the wheel 210.
  • the control device 205 of the vehicle 200 may execute the wheel runoff determination process.
  • the control device 205 of the vehicle 200 may execute the wheel runoff determination process based on information received from the sensor device 100.
  • a sensor capable of detecting a specific vibration component generated from loosening of the nut 240 of the wheel 210 is arranged on the vehicle 200 side rather than on the nut 240 side (such as a sensor that detects a wheel rotation speed signal used in an anti-lock brake system)
  • the control device 205 of the vehicle 200 may execute the wheel runoff determination process based on the detection result of the sensor.
  • control device 205 of the vehicle 200 executes the wheel runoff determination process
  • the control device 205 may correspond to the "control unit" of this disclosure.
  • a determination device includes a sensor unit that outputs a signal indicating the state of a wheel attached to a vehicle body, and a control unit that executes a determination process to determine the presence or absence of a sign of wheel detachment based on the signal from the sensor unit. When a predetermined condition is satisfied, the control unit increases the frequency of execution of the determination process compared to when the predetermined condition is not satisfied.
  • the frequency with which the determination process is executed is not fixed to a constant frequency, but is switched depending on whether or not a specified condition is met. Specifically, when the specified condition is met, the frequency with which the determination process is executed is increased. This makes it possible to more accurately determine whether there are signs of a wheel falling off. On the other hand, when the specified condition is not met, the frequency with which the determination process is executed is not increased. This makes it possible to reduce the processing load on the control unit. As a result, it is possible to reduce the processing load on the control unit while maintaining the accuracy of the determination process.
  • the predetermined condition includes an elapsed condition regarding the period of time that has elapsed since the wheel was attached to the vehicle body.
  • the control unit increases the frequency of execution of the determination process compared to when the elapsed condition is not satisfied.
  • the predetermined conditions include an elapsed condition related to the period of time that has elapsed since the wheel was attached to the vehicle body. Then, when the elapsed condition is met, the control unit increases the frequency of execution of the determination process compared to when the elapsed condition is not met. This makes it possible to reduce the processing load on the control unit in situations where wheel detachment is unlikely to occur, while improving the accuracy of the determination process in situations where wheel detachment is likely to occur.
  • the predetermined conditions include a temperature condition related to the temperature in addition to the progress condition.
  • the control unit sets the execution frequency of the determination process to an initial frequency when neither the progress condition nor the temperature condition is satisfied, and sets the execution frequency of the determination process to be higher than the initial frequency when at least one of the progress condition and the temperature condition is satisfied.
  • the predetermined conditions include a temperature condition related to the temperature in addition to the time that has elapsed. Then, when at least one of the elapsed condition and the temperature condition is satisfied, the control unit increases the frequency of execution of the determination process above the initial frequency. This makes it possible to reduce the processing load on the control unit in situations where wheel detachment is unlikely to occur, while improving the accuracy of the determination process in situations where wheel detachment is likely to occur.
  • control unit sets the execution frequency of the determination process to a first frequency higher than the initial frequency when one of the elapsed condition and the temperature condition is met and the other is not met, and sets the execution frequency of the determination process to a second frequency higher than the first frequency when both the elapsed condition and the temperature condition are met.
  • the execution frequency of the determination process when only one of the elapsed conditions and the temperature condition is met, the execution frequency of the determination process is set to a first frequency, but when both conditions are met, in consideration of the higher possibility of wheel detachment compared to when only one of the conditions is met, the execution frequency of the determination process is set to a second frequency higher than the first frequency. This makes it possible to further improve the accuracy of the determination process while reducing the load on the control unit.
  • the temperature condition includes at least one of the following conditions: the outside air temperature is lower than a predetermined value, and the average air temperature during a predetermined period is lower than a predetermined value.
  • the frequency of execution of the determination process can be increased at times or periods when wheel detachment is likely to occur, thereby improving the accuracy of the determination process.
  • the elapsed condition includes at least one of the following conditions: the time elapsed since the wheel was attached to the vehicle body is less than a predetermined value, or the number of times the determination process or the predetermined process has been executed since the wheel was attached to the vehicle body is less than a predetermined value.
  • the accuracy of the determination process can be improved by increasing the frequency of execution of the determination process within a predetermined period after the wheel is removed, during which time wheel detachment is likely to occur.
  • 1 acceleration sensor, 2 signal processing unit, 3 communication unit, 4 power supply unit 100 sensor device, 200 vehicle, 201 communication terminal, 202 button, 203 outside air temperature sensor, 205 control device, 210 wheel, 220 wheel, 221 wheel hole, 222 inner wheel, 223 outer wheel, 230 tire, 240 nut, 241 nut cap, 241a ceiling portion, 241b side portion, 241c inner surface, 243 washer, 250 bolt, 250a wheel hub, 251 tip portion.

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Abstract

A sensor device (100) comprises: an acceleration sensor (1) that outputs a signal indicating the state of a wheel which is attached to a vehicle body; and a signal processing unit (2) that executes a wheel detachment determination process for determining whether there is any sign of detachment of the wheel, on the basis of the signal from the acceleration sensor (1). When a prescribed switching condition has been established, the signal processing unit (2) increases the frequency of execution of the wheel detachment determination process compared to when a switching condition has not been established. The switching condition includes a temperature condition that the external air temperature is lower than a threshold temperature and an elapse condition that the elapsed time from the time of mounting or dismounting a wheel is less than a threshold time.

Description

判定装置Judging device
　本開示は、車輪脱落の予兆の有無を判定する判定装置に関する。 This disclosure relates to a determination device that determines whether there are signs of a wheel coming off.
　特開２００５－３２９９０７号公報（特許文献１）には、車輪（タイヤあるいはホイール）に取り付けられた検出器の検出値に基づいて、車輪脱落の予兆（車輪を車体に取り付けるナットの緩み）の有無を判定する処理を行なう装置が開示されている。 JP 2005-329907 A (Patent Document 1) discloses a device that performs processing to determine whether there are signs of a wheel coming off (looseness of the nuts that attach the wheel to the vehicle body) based on the detection value of a detector attached to the wheel (tire or wheel).
特開２００５－３２９９０７号公報JP 2005-329907 A
　特開２００５－３２９９０７号公報に開示されたような判定処理を行なう装置において、通常、判定処理の実行頻度は一定の頻度に固定されているのが一般的である。検出処理の実行頻度が一律に高い値に固定されると、判定精度は向上するが、判定処理を行なう制御部の負荷が増大する。一方、判定処理の実行頻度が一律に低い値に固定されると、制御部の負荷を軽減することができるが、判定精度が低下してしまう。 In devices that perform a determination process such as that disclosed in JP 2005-329907 A, the frequency with which the determination process is performed is generally fixed at a certain frequency. If the frequency with which the detection process is performed is fixed uniformly to a high value, the determination accuracy improves, but the load on the control unit that performs the determination process increases. On the other hand, if the frequency with which the determination process is performed is fixed uniformly to a low value, the load on the control unit can be reduced, but the determination accuracy decreases.
　本開示は、上述の課題を解決するためになされたものであって、その目的は、車輪脱落の予兆の有無を判定する判定処理の精度を維持しつつ、判定処理を実行する制御部の負荷を軽減することである。 The present disclosure has been made to solve the above-mentioned problems, and its purpose is to reduce the load on the control unit that executes the determination process while maintaining the accuracy of the determination process for determining whether there are signs of wheel detachment.
　本開示の一態様による判定装置は、車体に取り付けられる車輪の状態を示す信号を出力するセンサ部と、センサ部からの信号に基づいて車輪の脱落の予兆の有無を判定する判定処理を実行する制御部とを備える。制御部は、所定条件が成立している場合、所定条件が成立していない場合に比べて、判定処理の実行頻度を高くする。 The determination device according to one aspect of the present disclosure includes a sensor unit that outputs a signal indicating the state of a wheel attached to a vehicle body, and a control unit that executes a determination process that determines whether there are signs of a wheel falling off based on the signal from the sensor unit. When a predetermined condition is met, the control unit executes the determination process more frequently than when the predetermined condition is not met.
　上記の態様によれば、判定処理の実行頻度が、一定の頻度に固定されるのではなく、所定条件の成否に応じて切り替えられる。具体的には、所定条件が成立している場合には、判定処理の実行頻度が高くされる。これにより、車輪の脱落の予兆の有無をより精度よく判定することができる。一方、所定条件が成立していない場合には、判定処理の実行頻度は高くされない。これにより、判定処理を実行する制御部の処理負荷を軽減することができる。その結果、判定処理による判定精度を維持しつつ、制御部の処理負荷を軽減することができる。 According to the above aspect, the frequency with which the determination process is executed is not fixed to a constant frequency, but is switched depending on whether or not a specified condition is met. Specifically, when the specified condition is met, the frequency with which the determination process is executed is increased. This makes it possible to more accurately determine whether there are signs of a wheel falling off. On the other hand, when the specified condition is not met, the frequency with which the determination process is executed is not increased. This makes it possible to reduce the processing load on the control unit that executes the determination process. As a result, it is possible to reduce the processing load on the control unit while maintaining the accuracy of the determination made by the determination process.
　本開示によれば、車輪脱落の予兆の有無を判定する判定処理の精度を維持しつつ、判定処理を実行する制御部の負荷を軽減することができる。 According to the present disclosure, it is possible to reduce the load on the control unit that executes the determination process while maintaining the accuracy of the determination process for determining whether there are signs of wheel detachment.
判定装置が搭載される車両を模式的に示す図である。1 is a diagram illustrating a vehicle on which a determination device is mounted; センサ装置が配置されるナットの断面の一例を示す図である。FIG. 2 is a diagram showing an example of a cross section of a nut on which a sensor device is disposed. センサ装置の構成の一例を示す図である。FIG. 2 is a diagram illustrating an example of a configuration of a sensor device. 車輪脱落の月別発生件数を示す図である。FIG. 13 is a diagram showing the monthly occurrence number of wheel detachments. 車輪脱着後の期間別の車輪脱落の発生件数を示す図である。FIG. 13 is a diagram showing the number of wheel detachment occurrences by period after the wheels are removed. センサ装置の処理手順の一例を示すフローチャート（その１）である。11 is a flowchart (part 1) illustrating an example of a processing procedure of the sensor device. センサ装置の処理手順の一例を示すフローチャート（その２）である。13 is a flowchart (part 2) illustrating an example of a processing procedure of the sensor device.
　以下、本開示の実施の形態について、図面を参照しながら詳細に説明する。なお、図中同一または相当部分には同一符号を付してその説明は繰り返さない。 Below, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings will be given the same reference numerals and their description will not be repeated.
　図１は、本実施の形態による判定装置が搭載される車両２００を模式的に示す図である。車両２００は、通信端末２０１と、ボタン２０２と、外気温センサ２０３と、制御装置２０５と、複数の車輪２１０とを備える。 FIG. 1 is a schematic diagram of a vehicle 200 equipped with a determination device according to this embodiment. The vehicle 200 includes a communication terminal 201, a button 202, an outside air temperature sensor 203, a control device 205, and a number of wheels 210.
　複数の車輪２１０の各々は、ホイール２２０と、ホイール２２０に取り付けられるタイヤ２３０とを含む。 Each of the multiple wheels 210 includes a wheel 220 and a tire 230 attached to the wheel 220.
　各車輪２１０のホイール２２０は、５つのナット２４０により車両２００の車体（より詳しくは図２に示すホイールハブ２５０ａ）に取り付けられている。なお、各車輪２１０のナット２４０の個数は５つに限定されるものではない。 The wheel 220 of each wheel 210 is attached to the body of the vehicle 200 (more specifically, the wheel hub 250a shown in FIG. 2) by five nuts 240. Note that the number of nuts 240 on each wheel 210 is not limited to five.
　各車輪２１０を車体に取り付ける５つのナット２４０のうちの１つには、センサ装置１００が配置される。なお、センサ装置１００は、各車輪２１０を車体に取り付ける５つのナット２４０のうちの２つ以上に配置されていてもよい。本実施の形態によるセンサ装置１００は、本開示の「判定装置」の一例である。 The sensor device 100 is disposed on one of the five nuts 240 that attach each wheel 210 to the vehicle body. The sensor device 100 may be disposed on two or more of the five nuts 240 that attach each wheel 210 to the vehicle body. The sensor device 100 according to this embodiment is an example of the "determination device" of the present disclosure.
　図２は、センサ装置１００が配置されるナット２４０の断面の一例を示す図である。なお、図２には、ダブルタイヤの例が示されている。ダブルタイヤにおいては、ホイール２２０は、内側ホイール２２２と外側ホイール２２３とで構成される。 FIG. 2 is a diagram showing an example of a cross section of a nut 240 in which the sensor device 100 is disposed. Note that FIG. 2 shows an example of a double tire. In a double tire, the wheel 220 is composed of an inner wheel 222 and an outer wheel 223.
　ホイール２２０には、ホイール穴２２１が設けられている。ホイール穴２２１には、ホイールハブ２５０ａに固定されているボルト２５０が挿入（貫通）される。ナット２４０は、ホイール穴２２１に挿入された状態のボルト２５０をホイール２２０に締結する。 The wheel 220 has a wheel hole 221. A bolt 250 fixed to a wheel hub 250a is inserted (passes through) into the wheel hole 221. The nut 240 fastens the bolt 250 inserted into the wheel hole 221 to the wheel 220.
　ナット２４０には、ナットキャップ２４１が取り付けられている。ナットキャップ２４１は、天井部２４１ａと、側面部２４１ｂとを含む。側面部２４１ｂは、ボルト２５０のうちホイール穴２２１を貫通した部分を周状に取り囲むように設けられている。天井部２４１ａは、ボルト２５０の先端部２５１と（ボルト２５０の挿入方向に）対向するように設けられている。天井部２４１ａは、側面部２４１ｂと連続的に設けられている。なお、ナット２４０とホイール２２０との間には、ワッシャ２４３が設けられていてもよい。 A nut cap 241 is attached to the nut 240. The nut cap 241 includes a ceiling portion 241a and a side portion 241b. The side portion 241b is provided so as to circumferentially surround the portion of the bolt 250 that passes through the wheel hole 221. The ceiling portion 241a is provided so as to face the tip portion 251 of the bolt 250 (in the direction in which the bolt 250 is inserted). The ceiling portion 241a is provided continuously with the side portion 241b. A washer 243 may be provided between the nut 240 and the wheel 220.
　センサ装置１００は、ナットキャップ２４１の天井部２４１ａの内表面２４１ｃに取り付けられて（接着されて）いる。したがって、センサ装置１００は、ボルト２５０が収容されるナットキャップ２４１の空間Ｓ内に配置されている。なお、センサ装置１００は、ナットキャップ２４１ではなくナット２４０自体に取り付けられてもよい。 The sensor device 100 is attached (glued) to the inner surface 241c of the ceiling portion 241a of the nut cap 241. Therefore, the sensor device 100 is disposed in the space S of the nut cap 241 in which the bolt 250 is housed. Note that the sensor device 100 may be attached to the nut 240 itself, rather than to the nut cap 241.
　センサ装置１００は、車体に対する車輪２１０の取付状態を示す信号を出力するセンサ（たとえば加速度センサ）を備え、そのセンサからの信号に基づいて車輪２１０の脱落の予兆（ナット２４０の緩み）の有無を判定する。 The sensor device 100 is equipped with a sensor (e.g., an acceleration sensor) that outputs a signal indicating the mounting state of the wheel 210 relative to the vehicle body, and determines whether there are any signs of the wheel 210 falling off (looseness of the nut 240) based on the signal from the sensor.
　図３は、センサ装置１００の構成の一例を示す図である。図３には、センサ装置１００が車輪２１０の脱落の予兆（ナット２４０の緩み）の有無を加速度センサを用いて判定する場合の構成が例示されている。なお、センサ装置１００が車輪２１０の脱落の予兆の有無を判定するために用いられるセンサは、必ずしも加速度センサに限定されず、たとえば磁気センサであってもよい。 FIG. 3 is a diagram showing an example of the configuration of the sensor device 100. FIG. 3 illustrates an example of the configuration in which the sensor device 100 uses an acceleration sensor to determine whether there are signs of the wheel 210 falling off (looseness of the nut 240). Note that the sensor used by the sensor device 100 to determine whether there are signs of the wheel 210 falling off is not necessarily limited to an acceleration sensor, and may be, for example, a magnetic sensor.
　センサ装置１００は、加速度センサ１と、信号処理部２と、通信部３と、電源部４とを備える。加速度センサ１は、たとえば、ホイール２２０の回転軸に対して直交する平面において互いに直交する２つの軸（Ｘ軸およびＹ軸）の各々の加速度を検出する。加速度センサ１は、本開示の「センサ部」の一例である。 The sensor device 100 includes an acceleration sensor 1, a signal processing unit 2, a communication unit 3, and a power supply unit 4. The acceleration sensor 1 detects, for example, the acceleration of each of two mutually orthogonal axes (X-axis and Y-axis) in a plane perpendicular to the rotation axis of the wheel 220. The acceleration sensor 1 is an example of a "sensor unit" of the present disclosure.
　通信部３は、車両２００の通信端末２０１（図１参照）との間で無線通信可能に構成される。通信部３は、信号処理部２の処理結果を示す信号を車両２００の通信端末２０１（図１参照）に送信する。また、通信部３は、車両２００の通信端末２０１（図１参照）から送信された情報を受信して信号処理部２に送信する。 The communication unit 3 is configured to be capable of wireless communication with the communication terminal 201 (see FIG. 1) of the vehicle 200. The communication unit 3 transmits a signal indicating the processing result of the signal processing unit 2 to the communication terminal 201 (see FIG. 1) of the vehicle 200. The communication unit 3 also receives information transmitted from the communication terminal 201 (see FIG. 1) of the vehicle 200 and transmits it to the signal processing unit 2.
　電源部４は、加速度センサ１、信号処理部２、および、通信部３の各々に電力を供給する。電源部４は、たとえばボタン電池などで実現することができる。 The power supply unit 4 supplies power to each of the acceleration sensor 1, the signal processing unit 2, and the communication unit 3. The power supply unit 4 can be realized, for example, by a button battery.
　信号処理部２は、図示されないＣＰＵ等のプロセッサと、メモリと、入出力バッファとを含んで構成される。加速度センサ１からの信号（Ｘ軸方向の加速度およびＹ軸方向の加速度）に基づいてナット２４０が緩んでいるか否かを判定し、その判定結果に基づいて車輪２１０の脱落の予兆の有無を判定し、その判定結果を通信部３から車両２００の通信端末２０１に送信する処理（以下「脱輪判定処理」ともいう）を実行する。信号処理部２は、加速度センサ１からの信号に基づいてナット２４０が緩んでいると判定される場合には車輪２１０の脱落の予兆が有ると判定し、その判定結果を通信部３から車両２００の通信端末２０１に送信する。一方、加速度センサ１からの信号に基づいてナット２４０が緩んでいると判定されない場合には車輪２１０の脱落の予兆が無いと判定し、その判定結果を通信部３から車両２００の通信端末２０１に送信する。信号処理部２は、本開示の「制御部」の一例である。 The signal processing unit 2 is configured to include a processor such as a CPU (not shown), a memory, and an input/output buffer. It executes a process (hereinafter also referred to as a "wheel-falling determination process") to determine whether the nut 240 is loose or not based on the signal from the acceleration sensor 1 (acceleration in the X-axis direction and acceleration in the Y-axis direction), determine whether there is a sign of the wheel 210 falling off based on the determination result, and transmit the determination result from the communication unit 3 to the communication terminal 201 of the vehicle 200. If the signal processing unit 2 determines that the nut 240 is loose based on the signal from the acceleration sensor 1, it determines that there is a sign of the wheel 210 falling off, and transmits the determination result from the communication unit 3 to the communication terminal 201 of the vehicle 200. On the other hand, if the signal from the acceleration sensor 1 does not determine that the nut 240 is loose, it determines that there is no sign of the wheel 210 falling off, and transmits the determination result from the communication unit 3 to the communication terminal 201 of the vehicle 200. The signal processing unit 2 is an example of a "control unit" in this disclosure.
　図１に戻って、通信端末２０１は、各車輪２１０のセンサ装置１００との間で無線通信可能に構成される。 Returning to FIG. 1, the communication terminal 201 is configured to be capable of wireless communication with the sensor device 100 of each wheel 210.
　制御装置２０５は、図示されないＣＰＵ（Central　Processing　Unit）等のプロセッサと、メモリと、入出力バッファとを含んで構成される。制御装置２０５は、車輪２１０のセンサ装置１００から通信端末２０１が受信した信号に基づいて、車輪２１０の状態を監視する。 The control device 205 includes a processor such as a CPU (Central Processing Unit) (not shown), a memory, and an input/output buffer. The control device 205 monitors the state of the wheel 210 based on a signal received by the communication terminal 201 from the sensor device 100 of the wheel 210.
　ボタン２０２は、少なくとも１つの車輪２１０の脱着作業をユーザが行なった場合に、ユーザによって押されるボタンである。ユーザがボタン２０２を押すと、ボタン２０２は、ユーザによって押されたことを示す信号を制御装置２０５に出力する。 Button 202 is a button that is pressed by the user when the user performs the operation of attaching or detaching at least one wheel 210. When the user presses button 202, button 202 outputs a signal indicating that it has been pressed by the user to control device 205.
　外気温センサ２０３は、外気温Ｔｏｕｔを検出し、検出結果を示す信号を制御装置２０５に出力する。 The outside air temperature sensor 203 detects the outside air temperature Tout and outputs a signal indicating the detection result to the control device 205.
　制御装置２０５は、外気温センサ２０３によって検出された外気温Ｔｏｕｔを示す信号を、無線通信により、通信端末２０１からセンサ装置１００の通信部３に送信する。 The control device 205 transmits a signal indicating the outside air temperature Tout detected by the outside air temperature sensor 203 from the communication terminal 201 to the communication unit 3 of the sensor device 100 via wireless communication.
　制御装置２０５は、ユーザによってボタン２０２が押された場合、少なくとも１つの車輪２１０の脱着作業が行なわれたことを示す信号（以下「車輪脱着信号」とも称する）を、無線通信により、通信端末２０１からセンサ装置１００の通信部３に送信する。 When the user presses the button 202, the control device 205 transmits a signal indicating that at least one wheel 210 has been detached (hereinafter also referred to as a "wheel detachment signal") from the communication terminal 201 to the communication unit 3 of the sensor device 100 via wireless communication.
　＜脱輪判定処理の実行頻度の切替＞
　本実施の形態によるセンサ装置１００は、上述の脱輪判定処理の実行頻度Ｆを、所定の切替条件の成否に応じて切り替えるように構成されている。 <Switching the execution frequency of the wheel run detection process>
The sensor device 100 according to this embodiment is configured to switch the execution frequency F of the above-mentioned wheel-off determination process depending on whether a predetermined switching condition is met.
　近年の車輪脱落の発生状況を考察すると、車輪脱落の発生には、車輪脱落発生時の環境温度（外気温）、および車輪脱着後の経過期間（ユーザによる車輪脱着作業時から車輪脱落発生時までの期間）が関係していることが推察される。 Considering the occurrence of wheel detachment in recent years, it is surmised that the occurrence of wheel detachment is related to the environmental temperature (outside temperature) at the time the wheel detaches and the period of time that has passed since the wheel was removed (the period from when the user removed the wheel to when the wheel detached).
　図４は、近年の日本国での車輪脱落の月別発生件数を示す図である。図４に示すように、車輪脱落の発生は、１１月から２月までの寒い時期（冬期）に集中している。この状況から、車輪脱落には発生時の環境温度が関係している、より具体的には、車輪脱落は外気温が低い場合に発生し易いことが推察される。 Figure 4 shows the monthly number of wheel detachment incidents in Japan in recent years. As Figure 4 shows, wheel detachment incidents are concentrated in the cold months (winter) from November to February. From this situation, it can be inferred that wheel detachment is related to the environmental temperature at the time of occurrence, and more specifically, wheel detachment is more likely to occur when the outside temperature is low.
　図５は、近年の日本国での車輪脱着後の期間別の車輪脱落の発生件数を示す図である。図５に示すように、車輪脱落の発生は、ユーザによる車輪脱着作業後の１～２ヶ月の期間内に集中している。この状況から、車輪脱落は、車輪脱着後の経過期間が関係している、より具体的には、車輪脱着後の一定期間（１～２ヶ月）内に発生し易いことが推察される。 Figure 5 shows the number of wheel detachment incidents occurring in Japan in recent years, broken down by the period following wheel removal. As Figure 5 shows, wheel detachment incidents are concentrated within a period of one to two months after the user removes the wheels. From this situation, it can be inferred that wheel detachment is related to the period that has passed since the wheels were removed, and more specifically, wheel detachment is likely to occur within a certain period (one to two months) after the wheels are removed.
　上記のような推察結果に鑑み、本実施の形態においては、脱輪判定処理の実行頻度Ｆを切り替えるための切替条件として、外気温（環境温度）に関する「気温条件」と、車輪２１０の脱着後の期間に関する「経過条件」とが含まれる。 In light of the above-mentioned inference, in this embodiment, the switching conditions for switching the execution frequency F of the wheel-off determination process include a "temperature condition" related to the outside air temperature (ambient temperature) and a "time-lapse condition" related to the period after the wheel 210 is detached.
　「気温条件」は、外気温Ｔｏｕｔがしきい温度よりも低い、という条件である。しきい温度は、車輪脱落の発生が集中する寒い時期（冬期）であるか否かを判定可能な値に設定される。たとえば、しきい温度は、秋期から冬期に切り替わる時期の平均気温、あるいは、冬期から春期に切り替わる時期の平均気温に基づいて設定される。 The "temperature condition" is a condition in which the outside air temperature Tout is lower than a threshold temperature. The threshold temperature is set to a value that makes it possible to determine whether or not it is the cold season (winter) when wheel detachment occurs most frequently. For example, the threshold temperature is set based on the average temperature when the season changes from autumn to winter, or the average temperature when the season changes from winter to spring.
　「経過条件」は、車輪２１０の脱着時からの経過時間Ｔがしきい時間未満である、という条件である。しきい時間は、車輪脱落の発生が集中する、車輪脱着時からの１～２ヶ月の間の時間に設定される。 The "elapsed condition" is a condition that the time T that has elapsed since the wheel 210 was removed is less than a threshold time. The threshold time is set to a period of one to two months from the time the wheel was removed, during which time wheel detachment occurs most frequently.
　センサ装置１００の信号処理部２は、上述の気温条件および経過条件の少なくとも一方が成立している場合には、気温条件および経過条件の双方が成立していない場合よりも、脱輪判定処理の実行頻度Ｆを高くする。 When at least one of the temperature conditions and the elapsed conditions described above is met, the signal processing unit 2 of the sensor device 100 increases the frequency F of execution of the wheel runoff determination process compared to when neither the temperature condition nor the elapsed condition is met.
　図６は、センサ装置１００の信号処理部２が脱輪判定処理を実行する際の処理手順の一例を示すフローチャートである。 FIG. 6 is a flowchart showing an example of the processing procedure when the signal processing unit 2 of the sensor device 100 executes the wheel runoff determination process.
　信号処理部２は、外気温Ｔｏｕｔを取得する（ステップＳ１０）。たとえば、信号処理部２は、車両２００の通信端末２０１から外気温センサ２０３の検出結果を受信することによって、外気温Ｔｏｕｔを取得することができる。なお、センサ装置１００内に外気温センサが備えられる場合には、センサ装置１００内の外気温センサの検出結果を外気温Ｔｏｕｔとして取得するようにしてもよい。 The signal processing unit 2 acquires the outside air temperature Tout (step S10). For example, the signal processing unit 2 can acquire the outside air temperature Tout by receiving the detection result of the outside air temperature sensor 203 from the communication terminal 201 of the vehicle 200. Note that if an outside air temperature sensor is provided in the sensor device 100, the detection result of the outside air temperature sensor in the sensor device 100 may be acquired as the outside air temperature Tout.
　次いで、信号処理部２は、車輪脱着時からの経過時間Ｔを取得する（ステップＳ２０）。たとえば、信号処理部２は、車両２００の通信端末２０１から車輪脱着信号（車輪２１０の脱着作業が行なわれたことを示す信号）を受信した時からの経過時間をカウントし、カウントした経過時間を車輪脱着時からの経過時間Ｔとして取得することができる。 Then, the signal processing unit 2 acquires the elapsed time T from the time the wheels were detached (step S20). For example, the signal processing unit 2 can count the elapsed time from the time the wheel detachment signal (a signal indicating that the wheel 210 has been detached) was received from the communication terminal 201 of the vehicle 200, and acquire the counted elapsed time as the elapsed time T from the time the wheels were detached.
　また、加速度センサ１の出力が車輪脱着を示す態様で変化した場合に信号処理部２が初期化されるように構成されている場合には、初期化後における信号処理部２の処理頻度（処理周期）が事前に決まっていることに鑑み、初期化後における信号処理部２の脱輪判定処理または所定処理（たとえば、加速度センサ１の出力を計測する処理、もしくは電波を送信する処理）の実行回数をカウントし、カウントされた実行回数を車輪脱着時からの経過時間Ｔとして扱うようにしてもよい。このようにすることで、センサ装置１００の信号処理部２が、車両２００の通信端末２０１との通信を行なうことなく単独で車輪脱着時からの経過時間Ｔを把握することができる。 Furthermore, if the signal processing unit 2 is configured to be initialized when the output of the acceleration sensor 1 changes in a manner indicating wheel detachment, in view of the fact that the processing frequency (processing cycle) of the signal processing unit 2 after initialization is determined in advance, the number of times that the signal processing unit 2 executes the wheel detachment determination process or a predetermined process (for example, a process for measuring the output of the acceleration sensor 1 or a process for transmitting radio waves) after initialization may be counted, and the counted number of executions may be treated as the elapsed time T since the wheel detachment. In this way, the signal processing unit 2 of the sensor device 100 can independently determine the elapsed time T since the wheel detachment without communicating with the communication terminal 201 of the vehicle 200.
　次いで、信号処理部２は、ステップＳ１０で取得された外気温Ｔｏｕｔが上述のしきい温度よりも低いか否かを判定する（ステップＳ３０）。すなわち、信号処理部２は、ステップＳ３０において、上述の気温条件の成否を判定する。 Then, the signal processing unit 2 determines whether the outside air temperature Tout acquired in step S10 is lower than the above-mentioned threshold temperature (step S30). That is, in step S30, the signal processing unit 2 determines whether the above-mentioned air temperature condition is met.
　また、信号処理部２は、ステップＳ２０で取得された車輪脱着時からの経過時間Ｔが上述のしきい時間未満であるか否かを判定する（ステップＳ４０）。すなわち、信号処理部２は、ステップＳ４０において、上述の経過条件の成否を判定する。 The signal processing unit 2 also determines whether the elapsed time T from the time the wheel was attached or detached, which is acquired in step S20, is less than the above-mentioned threshold time (step S40). That is, in step S40, the signal processing unit 2 determines whether the above-mentioned elapsed condition is met.
　外気温Ｔｏｕｔがしきい温度よりも高い場合（ステップＳ３０においてＮＯ）であって、かつ車輪脱着時からの経過時間Ｔがしきい時間を超えている場合（ステップＳ４０においてＮＯ）、すなわち気温条件および経過条件の双方が成立していない場合、車輪脱落が発生する可能性は低いことが想定されるため、信号処理部２は、脱輪判定処理の実行頻度Ｆを初期値Ｆ０に設定する（ステップＳ６０）。 If the outside air temperature Tout is higher than the threshold temperature (NO in step S30) and the time T that has elapsed since the wheel was removed exceeds the threshold time (NO in step S40), that is, if both the air temperature condition and the time elapsed condition are not met, it is assumed that the possibility of the wheel falling off is low, so the signal processing unit 2 sets the execution frequency F of the wheel-off determination process to the initial value F0 (step S60).
　一方、外気温Ｔｏｕｔがしきい温度よりも低い場合（ステップＳ３０においてＹＥＳ）、あるいは、車輪脱着時からの経過時間Ｔがしきい時間未満である場合（ステップＳ４０においてＹＥＳ）、すなわち上述の気温条件および経過条件の少なくとも一方が成立している場合、車輪脱落が発生する可能性があることが想定されるため、信号処理部２は、脱輪判定処理の実行頻度Ｆを初期値Ｆ０よりも高い所定値Ｆ２に設定する（ステップＳ５０）。たとえば、初期値Ｆ０が３０秒毎に１回の頻度である場合、所定値Ｆ２は１０秒毎に１回の頻度に設定される。 On the other hand, if the outside air temperature Tout is lower than the threshold temperature (YES in step S30), or if the time T that has elapsed since the wheel was removed is less than the threshold time (YES in step S40), that is, if at least one of the above-mentioned temperature conditions and elapsed conditions is met, it is assumed that the wheel may fall off, so the signal processing unit 2 sets the execution frequency F of the wheel-off determination process to a predetermined value F2 that is higher than the initial value F0 (step S50). For example, if the initial value F0 is a frequency of once every 30 seconds, the predetermined value F2 is set to a frequency of once every 10 seconds.
　次いで、信号処理部２は、ステップＳ５０あるいはステップＳ６０で設定された実行頻度Ｆで脱輪判定処理を実行する（ステップＳ７０）。 Then, the signal processing unit 2 executes the wheel runoff determination process at the execution frequency F set in step S50 or step S60 (step S70).
　以上のように、本実施の形態による信号処理部２は、脱輪判定処理の実行頻度Ｆを、一定値に固定するのではなく、気温条件および経過条件の成否に応じて切り替える。 As described above, the signal processing unit 2 in this embodiment does not fix the execution frequency F of the wheel runoff determination process to a constant value, but switches it depending on whether the temperature conditions and elapsed conditions are met.
　具体的には、気温条件および経過条件の少なくとも一方が成立している場合、信号処理部２は、脱輪判定処理の実行頻度Ｆを初期値Ｆ０よりも高い所定値Ｆ２に設定する。これにより、車輪脱落が発生する可能性がある状況において、車輪２１０の脱落の予兆の有無を精度よく判定することができる。一方、気温条件および経過条件の双方が成立していない場合には、信号処理部２は、脱輪判定処理の実行頻度Ｆを所定値Ｆ２よりも低い初期値Ｆ０に設定する。これにより、車輪脱落が発生する可能性が低い状況において、信号処理部２の処理負荷を軽減することができる。その結果、脱輪判定処理による判定精度を維持しつつ、信号処理部２の処理負荷を軽減することができる。 Specifically, when at least one of the temperature condition and the elapsed condition is met, the signal processing unit 2 sets the execution frequency F of the wheel derailment determination process to a predetermined value F2, which is higher than the initial value F0. This makes it possible to accurately determine whether there are signs of wheel 210 falling off in a situation where there is a possibility of wheel derailment. On the other hand, when neither the temperature condition nor the elapsed condition is met, the signal processing unit 2 sets the execution frequency F of the wheel derailment determination process to an initial value F0, which is lower than the predetermined value F2. This makes it possible to reduce the processing load on the signal processing unit 2 in a situation where there is a low possibility of wheel derailment. As a result, it is possible to reduce the processing load on the signal processing unit 2 while maintaining the determination accuracy of the wheel derailment determination process.
　また、脱輪判定処理の実行頻度Ｆを所定値Ｆ２に固定する場合に比べて、信号処理部２の作動に要する電力が抑えられるため、電源部４（たとえばボタン電池）の寿命を延ばすことができる。 In addition, the power required to operate the signal processing unit 2 is reduced compared to when the frequency F of execution of the wheel runoff determination process is fixed at a predetermined value F2, so the life of the power supply unit 4 (e.g., a button battery) can be extended.
　［変形例１］
　上述の実施の形態においては、気温条件および経過条件の少なくとも一方が成立している場合には、気温条件および経過条件の双方が成立しているか否かに関わらず、脱輪判定処理の実行頻度Ｆが同じ値（所定値Ｆ２）に設定される。 [Modification 1]
In the above-described embodiment, when at least one of the temperature condition and the elapsed condition is met, the frequency F of execution of the wheel run-off determination process is set to the same value (predetermined value F2) regardless of whether both the temperature condition and the elapsed condition are met.
　これに対し、本変形例１では、温度条件および経過条件の双方が成立している場合には、温度条件および経過条件の一方のみが成立している場合に比べて、脱輪判定処理の実行頻度Ｆをより高い値に設定する。 In contrast, in this first modified example, when both the temperature condition and the elapsed time condition are met, the frequency F of execution of the wheel runoff determination process is set to a higher value than when only one of the temperature condition and the elapsed time condition is met.
　図７は、本変形例１によるセンサ装置１００の信号処理部２が脱輪判定処理を実行する際の処理手順の一例を示すフローチャートである。図７のフローチャートは、上述の図６にフローチャートのステップＳ５０に代えて、ステップＳ５１～Ｓ５４を追加したものである。図７のその他のステップ（図６に示したステップと同じ番号を付しているステップ）については、既に説明したため詳細な説明はここでは繰り返さない。 FIG. 7 is a flowchart showing an example of the processing procedure when the signal processing unit 2 of the sensor device 100 according to this modified example 1 executes the wheel runoff determination process. The flowchart in FIG. 7 is the same as that in FIG. 6 above, except that steps S51 to S54 have been added instead of step S50. The other steps in FIG. 7 (the steps having the same numbers as the steps shown in FIG. 6) have already been explained, so detailed explanations will not be repeated here.
　外気温Ｔｏｕｔがしきい温度よりも高い場合（ステップＳ３０においてＮＯ）であって、かつ車輪脱着時からの経過時間Ｔがしきい時間を超えている場合（ステップＳ４０においてＮＯ）、すなわち温度条件および経過条件の双方が成立していない場合、信号処理部２は、脱輪判定処理の実行頻度Ｆを初期値Ｆ０に設定する（ステップＳ６０）。 If the outside air temperature Tout is higher than the threshold temperature (NO in step S30) and the elapsed time T from when the wheel was removed exceeds the threshold time (NO in step S40), i.e., if both the temperature condition and the elapsed condition are not met, the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to the initial value F0 (step S60).
　外気温Ｔｏｕｔがしきい温度よりも高い場合（ステップＳ３０においてＮＯ）であって、かつ車輪脱着時からの経過時間Ｔがしきい時間未満である場合（ステップＳ４０においてＹＥＳ）、すなわち温度条件および経過条件のうちの経過条件のみが成立している場合、信号処理部２は、脱輪判定処理の実行頻度Ｆを初期値Ｆ０よりも高い所定値Ｆ１に設定する（ステップＳ５４）。たとえば、初期値Ｆ０が３０秒毎に１回の頻度である場合、所定値Ｆ１は１０秒毎に１回の頻度に設定される。 If the outside air temperature Tout is higher than the threshold temperature (NO in step S30) and the time T that has elapsed since the wheel was removed is less than the threshold time (YES in step S40), that is, if only the elapsed condition of the temperature condition and the elapsed condition is satisfied, the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to a predetermined value F1 that is higher than the initial value F0 (step S54). For example, if the initial value F0 is a frequency of once every 30 seconds, the predetermined value F1 is set to a frequency of once every 10 seconds.
　信号処理部２は、外気温Ｔｏｕｔがしきい温度よりも低い場合（ステップＳ３０においてＹＥＳ）、車輪脱着時からの経過時間Ｔがしきい時間未満であるか否かを判定する（ステップＳ５１）。 If the outside air temperature Tout is lower than the threshold temperature (YES in step S30), the signal processing unit 2 determines whether the elapsed time T from when the wheels were removed is less than the threshold time (step S51).
　外気温Ｔｏｕｔがしきい温度よりも低い場合（ステップＳ３０においてＹＥＳ）であって、かつ車輪脱着時からの経過時間Ｔがしきい時間を超えている場合（ステップＳ５１においてＮＯ）、すなわち温度条件および経過条件のうちの温度条件のみが成立している場合、信号処理部２は、脱輪判定処理の実行頻度Ｆを所定値Ｆ２ｂに設定する（ステップＳ５３）。所定値Ｆ２ｂは、所定値Ｆ１以上の頻度に設定される。たとえば、所定値Ｆ１が１０秒毎に１回の頻度である場合、所定値Ｆ２ｂは、所定値Ｆ１と同じ１０秒毎に１回の頻度、あるいは所定値Ｆ１よりも多い８秒毎に１回の頻度に設定される。 If the outside air temperature Tout is lower than the threshold temperature (YES in step S30) and the elapsed time T from when the wheel was removed exceeds the threshold time (NO in step S51), that is, if only the temperature condition of the temperature condition and the elapsed condition is satisfied, the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to a predetermined value F2b (step S53). The predetermined value F2b is set to a frequency equal to or greater than the predetermined value F1. For example, if the predetermined value F1 is a frequency of once every 10 seconds, the predetermined value F2b is set to a frequency of once every 10 seconds, the same as the predetermined value F1, or to a frequency of once every 8 seconds, which is greater than the predetermined value F1.
　外気温Ｔｏｕｔがしきい温度よりも低く（ステップＳ３０においてＹＥＳ）、かつ、車輪脱着時からの経過時間Ｔがしきい時間未満である場合（ステップＳ５１においてＹＥＳ）、すなわち温度条件および経過条件の双方が成立している場合、信号処理部２は、脱輪判定処理の実行頻度Ｆを所定値Ｆ２ａに設定する（ステップＳ５２）。所定値Ｆ２ａは、所定値Ｆ２ｂよりも高い頻度に設定される。たとえば、所定値Ｆ２ｂが８秒毎に１回の頻度である場合、所定値Ｆ２ａは、４秒毎に１回の頻度に設定される。 If the outside air temperature Tout is lower than the threshold temperature (YES in step S30) and the elapsed time T from when the wheel was removed is less than the threshold time (YES in step S51), that is, if both the temperature condition and the elapsed condition are met, the signal processing unit 2 sets the execution frequency F of the wheel removal determination process to a predetermined value F2a (step S52). The predetermined value F2a is set to a frequency higher than the predetermined value F2b. For example, if the predetermined value F2b is a frequency of once every 8 seconds, the predetermined value F2a is set to a frequency of once every 4 seconds.
　以上のように、温度条件および経過条件の双方が成立している場合には、温度条件および経過条件の一方のみが成立している場合に比べて、脱輪判定処理の実行頻度Ｆをより高い値に設定するようにしてもよい。このようにすることで、信号処理部２の負荷を軽減しつつ、脱輪判定処理による判定精度をさらに向上させることができる。 As described above, when both the temperature condition and the elapsed condition are met, the frequency F of execution of the wheel runoff detection process may be set to a higher value compared to when only one of the temperature condition and the elapsed condition is met. By doing so, it is possible to further improve the accuracy of the wheel runoff detection process while reducing the load on the signal processing unit 2.
　［変形例２］
　上述の実施の形態においては気温条件を外気温Ｔｏｕｔがしきい温度よりも低いという条件にしたが、気温条件は、外気温Ｔｏｕｔがしきい温度よりも低いという条件に代えてあるいは加えて、現在の時期が月間平均気温がしきい温度よりも低い時期であるという条件にしてもよい。また、気温条件に、寒い地域であるという条件を加えてもよい。 [Modification 2]
In the above embodiment, the temperature condition is that the outside air temperature Tout is lower than a threshold temperature, but instead of or in addition to the condition that the outside air temperature Tout is lower than a threshold temperature, the temperature condition may be that the current period is a period in which the monthly average temperature is lower than a threshold temperature. Also, a condition that the area is cold may be added to the temperature condition.
　また、上述の実施の形態においては経過条件を車輪脱着時からの経過時間Ｔがしきい時間未満であるという条件にしたが、経過条件を、車輪脱着時からの脱輪判定処理の実行回数がしきい回数未満であるという条件にしてもよい。 In addition, in the above embodiment, the elapsed condition is that the elapsed time T from when the wheels were detached is less than a threshold time, but the elapsed condition may be that the number of times the wheel-off determination process has been executed since the wheels were detached is less than a threshold number of times.
　［変形例３］
　上述の実施の形態においては各車輪２１０のナット２４０に配置されるセンサ装置１００が脱輪判定処理を実行するが、脱輪判定処理を実行する主体は、必ずしも車輪２１０のナット２４０に配置されるセンサ装置１００であることに限定されない。 [Modification 3]
In the above-described embodiment, the sensor device 100 arranged on the nut 240 of each wheel 210 performs the wheel derailment determination process, but the entity that performs the wheel derailment determination process is not necessarily limited to the sensor device 100 arranged on the nut 240 of the wheel 210.
　たとえば、車両２００の制御装置２０５が脱輪判定処理を実行するようにしてもよい。たとえば、車両２００の制御装置２０５が、センサ装置１００から受信した情報に基づいて脱輪判定処理を実行するようにしてもよい。また、ナット２４０側ではなく車両２００側に車輪２１０のナット２４０の緩みから発生する特有の振動成分を検出可能なセンサ（たとえばアンチロックブレーキシステムに用いられる車輪の回転速度信号を検出するセンサなど）が配置されている場合には、当該センサの検出結果に基づいて車両２００の制御装置２０５が脱輪判定処理を実行するようにしてもよい。 For example, the control device 205 of the vehicle 200 may execute the wheel runoff determination process. For example, the control device 205 of the vehicle 200 may execute the wheel runoff determination process based on information received from the sensor device 100. In addition, if a sensor capable of detecting a specific vibration component generated from loosening of the nut 240 of the wheel 210 is arranged on the vehicle 200 side rather than on the nut 240 side (such as a sensor that detects a wheel rotation speed signal used in an anti-lock brake system), the control device 205 of the vehicle 200 may execute the wheel runoff determination process based on the detection result of the sensor.
　車両２００の制御装置２０５が脱輪判定処理を実行する場合、当該制御装置２０５が本開示の「制御部」に相当し得る。 When the control device 205 of the vehicle 200 executes the wheel runoff determination process, the control device 205 may correspond to the "control unit" of this disclosure.
　今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本開示の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of the present disclosure is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.
　以上に説明した例示的な実施の形態およびその変形例は、以下の態様の具体例である。
　（第１項）　本開示による判定装置は、車体に取り付けられる車輪の状態を示す信号を出力するセンサ部と、センサ部からの信号に基づいて車輪の脱落の予兆の有無を判定する判定処理を実行する制御部とを備える。制御部は、所定条件が成立している場合、所定条件が成立していない場合に比べて、判定処理の実行頻度を高くする。 The exemplary embodiment and its modified examples described above are specific examples of the following aspects.
(1) A determination device according to the present disclosure includes a sensor unit that outputs a signal indicating the state of a wheel attached to a vehicle body, and a control unit that executes a determination process to determine the presence or absence of a sign of wheel detachment based on the signal from the sensor unit. When a predetermined condition is satisfied, the control unit increases the frequency of execution of the determination process compared to when the predetermined condition is not satisfied.
　上記の態様によれば、判定処理の実行頻度が、一定の頻度に固定されるのではなく、所定条件の成否に応じて切り替えられる。具体的には、所定条件が成立している場合には、判定処理の実行頻度が高くされる。これにより、車輪の脱落の予兆の有無をより精度よく判定することができる。一方、所定条件が成立していない場合には、判定処理の実行頻度は高くされない。これにより、制御部の処理負荷を軽減することができる。その結果、判定処理による判定精度を維持しつつ、制御部の処理負荷を軽減することができる。 According to the above aspect, the frequency with which the determination process is executed is not fixed to a constant frequency, but is switched depending on whether or not a specified condition is met. Specifically, when the specified condition is met, the frequency with which the determination process is executed is increased. This makes it possible to more accurately determine whether there are signs of a wheel falling off. On the other hand, when the specified condition is not met, the frequency with which the determination process is executed is not increased. This makes it possible to reduce the processing load on the control unit. As a result, it is possible to reduce the processing load on the control unit while maintaining the accuracy of the determination process.
　（第２項）　第１項に記載の判定装置において、所定条件は、車輪を車体に取り付けた時からの経過期間に関する経過条件を含む。制御部は、経過条件が成立している場合、経過条件が成立していない場合に比べて、判定処理の実行頻度を高くする。 (2) In the determination device described in 1, the predetermined condition includes an elapsed condition regarding the period of time that has elapsed since the wheel was attached to the vehicle body. When the elapsed condition is satisfied, the control unit increases the frequency of execution of the determination process compared to when the elapsed condition is not satisfied.
　上記の態様によれば、車輪脱落の発生には車輪脱着後の経過期間が関係していることに鑑み、所定条件には、車輪を車体に取り付けた時からの経過期間に関する経過条件が含まれる。そして、制御部は、経過条件が成立している場合は、そうでない場合に比べて判定処理の実行頻度を高くする。これにより、車輪脱落が発生する可能性が低い状況において制御部の処理負荷を軽減しつつ、車輪脱落が発生する可能性がある状況において判定処理の精度を向上させることができる。 In the above aspect, in view of the fact that the occurrence of wheel detachment is related to the period of time that has elapsed since the wheel was removed, the predetermined conditions include an elapsed condition related to the period of time that has elapsed since the wheel was attached to the vehicle body. Then, when the elapsed condition is met, the control unit increases the frequency of execution of the determination process compared to when the elapsed condition is not met. This makes it possible to reduce the processing load on the control unit in situations where wheel detachment is unlikely to occur, while improving the accuracy of the determination process in situations where wheel detachment is likely to occur.
　（第３項）　第２項に記載の判定装置において、所定条件は、経過条件に加えて、気温に関する気温条件を含む。制御部は、経過条件および気温条件の双方が成立していない場合は判定処理の実行頻度を初期頻度とし、経過条件および気温条件の少なくとも一方が成立した場合は判定処理の実行頻度を初期頻度よりも高くする。 (3) In the determination device described in 2, the predetermined conditions include a temperature condition related to the temperature in addition to the progress condition. The control unit sets the execution frequency of the determination process to an initial frequency when neither the progress condition nor the temperature condition is satisfied, and sets the execution frequency of the determination process to be higher than the initial frequency when at least one of the progress condition and the temperature condition is satisfied.
　上記の態様によれば、車輪脱落の発生には車輪脱着後の経過期間に加えて気温が関係していることに鑑み、所定条件には、経過期間に加えて、気温に関する気温条件が含まれる。そして、制御部は、経過条件および気温条件の少なくとも一方が成立した場合は、判定処理の実行頻度を初期頻度よりも高くする。これにより、車輪脱落が発生する可能性が低い状況において制御部の処理負荷を軽減しつつ、車輪脱落が発生する可能性がある状況において判定処理の精度を向上させることができる。 In the above aspect, in view of the fact that the occurrence of wheel detachment is related to temperature in addition to the time that has elapsed since the wheel was removed, the predetermined conditions include a temperature condition related to the temperature in addition to the time that has elapsed. Then, when at least one of the elapsed condition and the temperature condition is satisfied, the control unit increases the frequency of execution of the determination process above the initial frequency. This makes it possible to reduce the processing load on the control unit in situations where wheel detachment is unlikely to occur, while improving the accuracy of the determination process in situations where wheel detachment is likely to occur.
　（第４項）　第３項に記載の判定装置において、制御部は、経過条件および気温条件の一方が成立し、かつ他方が成立していない場合は判定処理の実行頻度を初期頻度よりも高い第１頻度とし、経過条件および気温条件の双方が成立している場合は判定処理の実行頻度を第１頻度よりも高い第２頻度とする。 (4) In the determination device described in 3, the control unit sets the execution frequency of the determination process to a first frequency higher than the initial frequency when one of the elapsed condition and the temperature condition is met and the other is not met, and sets the execution frequency of the determination process to a second frequency higher than the first frequency when both the elapsed condition and the temperature condition are met.
　上記の態様によれば、経過条件および気温条件のうちの一方の条件のみが成立している場合には判定処理の実行頻度を第１頻度としつつ、双方の条件が成立している場合には、一方の条件のみが成立している場合に比べて車輪脱落が発生する可能性が高いことに鑑み、判定処理の実行頻度を第１頻度よりも高い第２頻度にする。これにより、制御部の負荷を軽減しつつ、判定処理による判定精度をさらに向上させることができる。 According to the above aspect, when only one of the elapsed conditions and the temperature condition is met, the execution frequency of the determination process is set to a first frequency, but when both conditions are met, in consideration of the higher possibility of wheel detachment compared to when only one of the conditions is met, the execution frequency of the determination process is set to a second frequency higher than the first frequency. This makes it possible to further improve the accuracy of the determination process while reducing the load on the control unit.
　（第５項）　第３または４項に記載の判定装置において、気温条件は、外気温が所定値よりも低いという条件、および所定期間における平均気温が所定値よりも低い時期であるという条件の少なくとも一方を含む。 (5) In the determination device described in 3 or 4, the temperature condition includes at least one of the following conditions: the outside air temperature is lower than a predetermined value, and the average air temperature during a predetermined period is lower than a predetermined value.
　上記の態様によれば、車輪脱落が発生し易い時間あるいは時期に、判定処理の実行頻度を高くして判定処理による判定精度を向上させることができる。 According to the above aspect, the frequency of execution of the determination process can be increased at times or periods when wheel detachment is likely to occur, thereby improving the accuracy of the determination process.
　（第６項）　第２～５項のいずれかに記載の判定装置において、経過条件は、車輪を車体に取り付けた時点からの経過時間が所定値未満であるという条件、または、車輪を車体に取り付けた時からの判定処理または所定処理の実行回数が所定値未満であるという条件の少なくとも一方を含む。 (6) In the determination device described in any one of paragraphs 2 to 5, the elapsed condition includes at least one of the following conditions: the time elapsed since the wheel was attached to the vehicle body is less than a predetermined value, or the number of times the determination process or the predetermined process has been executed since the wheel was attached to the vehicle body is less than a predetermined value.
　上記の態様によれば、車輪脱落が発生し易い車輪脱着後の所定期間内に、判定処理の実行頻度を高くして判定処理による判定精度を向上させることができる。 According to the above aspect, the accuracy of the determination process can be improved by increasing the frequency of execution of the determination process within a predetermined period after the wheel is removed, during which time wheel detachment is likely to occur.
　１　加速度センサ、２　信号処理部、３　通信部、４　電源部、１００　センサ装置、２００　車両、２０１　通信端末、２０２　ボタン、２０３　外気温センサ、２０５　制御装置、２１０　車輪、２２０　ホイール、２２１　ホイール穴、２２２　内側ホイール、２２３　外側ホイール、２３０　タイヤ、２４０　ナット、２４１　ナットキャップ、２４１ａ　天井部、２４１ｂ　側面部、２４１ｃ　内表面、２４３　ワッシャ、２５０　ボルト、２５０ａ　ホイールハブ、２５１　先端部。 1 acceleration sensor, 2 signal processing unit, 3 communication unit, 4 power supply unit, 100 sensor device, 200 vehicle, 201 communication terminal, 202 button, 203 outside air temperature sensor, 205 control device, 210 wheel, 220 wheel, 221 wheel hole, 222 inner wheel, 223 outer wheel, 230 tire, 240 nut, 241 nut cap, 241a ceiling portion, 241b side portion, 241c inner surface, 243 washer, 250 bolt, 250a wheel hub, 251 tip portion.

Claims (6)

  1. 　車体に取り付けられる車輪の状態を示す信号を出力するセンサ部と、
    　前記センサ部からの信号に基づいて前記車輪の脱落の予兆の有無を判定する判定処理を実行する制御部とを備え、
    　前記制御部は、所定条件が成立している場合、前記所定条件が成立していない場合に比べて、前記判定処理の実行頻度を高くする、判定装置。     a sensor unit that outputs a signal indicating a state of a wheel attached to a vehicle body;
    a control unit that executes a determination process to determine whether or not there is a sign of the wheel falling off based on a signal from the sensor unit,
    The control unit increases the frequency of execution of the determination process when a predetermined condition is satisfied, compared to when the predetermined condition is not satisfied.
  2. 　前記所定条件は、前記車輪を前記車体に取り付けた時からの経過期間に関する経過条件を含み、
    　前記制御部は、前記経過条件が成立している場合、前記経過条件が成立していない場合に比べて、前記判定処理の実行頻度を高くする、請求項１に記載の判定装置。     the predetermined condition includes a period of time that has elapsed since the wheel was attached to the vehicle body,
    The determination device according to claim 1 , wherein the control unit increases the frequency of execution of the determination process when the elapsed condition is satisfied, compared to when the elapsed condition is not satisfied.
  3. 　前記所定条件は、前記経過条件に加えて、気温に関する気温条件を含み、
    　前記制御部は、
    　　前記経過条件および前記気温条件の双方が成立していない場合は前記判定処理の実行頻度を初期頻度とし、
    　　前記経過条件および前記気温条件の少なくとも一方が成立した場合は前記判定処理の実行頻度を前記初期頻度よりも高くする、請求項２に記載の判定装置。     The predetermined condition includes a temperature condition related to temperature in addition to the elapsed condition,
    The control unit is
    When neither the elapsed condition nor the temperature condition is satisfied, the execution frequency of the determination process is set to an initial frequency;
    The determination device according to claim 2 , wherein, when at least one of the elapsed condition and the temperature condition is satisfied, the frequency of execution of the determination process is made higher than the initial frequency.
  4. 　前記制御部は、
    　　前記経過条件および前記気温条件の一方が成立し、かつ他方が成立していない場合は前記判定処理の実行頻度を前記初期頻度よりも高い第１頻度とし、
    　　前記経過条件および前記気温条件の双方が成立している場合は前記判定処理の実行頻度を前記第１頻度よりも高い第２頻度とする、請求項３に記載の判定装置。     The control unit is
    When one of the elapsed condition and the temperature condition is satisfied and the other is not satisfied, a first frequency is set to be a frequency that is higher than the initial frequency.
    The determination device according to claim 3 , wherein, when both the elapsed condition and the temperature condition are satisfied, the determination process is executed at a second frequency that is higher than the first frequency.
  5. 　前記気温条件は、外気温が所定値よりも低いという条件、および所定期間における平均気温が所定値よりも低い時期であるという条件の少なくとも一方を含む、請求項３または４に記載の判定装置。 The determination device according to claim 3 or 4, wherein the temperature condition includes at least one of the following conditions: the outside air temperature is lower than a predetermined value, and the average air temperature during a predetermined period is lower than a predetermined value.
  6. 　前記経過条件は、前記車輪を前記車体に取り付けた時点からの経過時間が所定値未満であるという条件、または、前記車輪を前記車体に取り付けた時からの前記判定処理または所定処理の実行回数が所定値未満であるという条件の少なくとも一方を含む、請求項２～４のいずれかに記載の判定装置。 The determination device according to any one of claims 2 to 4, wherein the elapsed condition includes at least one of the following conditions: the elapsed time from the time the wheel was attached to the vehicle body is less than a predetermined value, or the number of times the determination process or the predetermined process has been executed since the wheel was attached to the vehicle body is less than a predetermined value.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH082221A (en) * 1994-06-21 1996-01-09 Toyota Motor Corp Abnormal tire pressure judging device
JP2016188769A (en) * 2015-03-30 2016-11-04 Ntn株式会社 Wheel nut looseness detection device and sensor unit for detecting the looseness
JP2018506470A (en) * 2015-01-27 2018-03-08 ニラ・ダイナミクス・エイビイ Loose wheel detection
JP2023066796A (en) * 2021-10-29 2023-05-16 株式会社東海理化電機製作所 Tire abnormality determination system
JP7409541B1 (en) * 2023-03-20 2024-01-09 いすゞ自動車株式会社 Instruction device and instruction method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH082221A (en) * 1994-06-21 1996-01-09 Toyota Motor Corp Abnormal tire pressure judging device
JP2018506470A (en) * 2015-01-27 2018-03-08 ニラ・ダイナミクス・エイビイ Loose wheel detection
JP2016188769A (en) * 2015-03-30 2016-11-04 Ntn株式会社 Wheel nut looseness detection device and sensor unit for detecting the looseness
JP2023066796A (en) * 2021-10-29 2023-05-16 株式会社東海理化電機製作所 Tire abnormality determination system
JP7409541B1 (en) * 2023-03-20 2024-01-09 いすゞ自動車株式会社 Instruction device and instruction method

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