JP2017009536A - Tire pneumatic pressure detector, tire pneumatic pressure monitor, and tire pneumatic pressure monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress switching between notification and notification stop of a notification part according to a temperature change following travel.SOLUTION: A controller of a transmitter measures as a transit time, a time when an acceleration detected by an acceleration sensor becomes a threshold for travel determination or higher. The controller transmits a transmitter signal in a first transmission frequency until the transit time reaches a low-frequency transmission time t1, and transmits the transmitter signal in a second transmission frequency having a higher frequency than the first transmission frequency from the low-frequency transmission time t1 until a set time t2.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a tire pressure detection device, a tire pressure monitoring device, and a tire pressure monitoring system.

  If the air pressure of the tire provided in the vehicle is excessively reduced, there is a risk of causing a reduction in fuel consumption or uneven wear in which part of the tire is worn unevenly. For this reason, in a vehicle, the tire air pressure is monitored, and the driver may be notified before the air pressure drops excessively.

  The tire pressure monitoring device described in Patent Literature 1 includes a transmitter provided on each of a plurality of wheels of a vehicle, and a receiver that operates a notification unit. The transmitter includes a pressure sensor that detects the tire air pressure, and transmits the tire air pressure detected by the pressure sensor to the receiver. The receiver activates the notification unit when the tire air pressure is below the alarm threshold.

JP 2012-228895 A

  Incidentally, the tire air pressure varies in proportion to the temperature in the tire. For this reason, before the start of traveling in a cold region or before the start of traveling in the winter season, the temperature in the tire becomes lower, so that the tire air pressure becomes lower. Further, when the vehicle starts running from this state, the temperature in the tire rises due to frictional heat generated in the tire and the tire air pressure increases. As a result, the air pressure of the tire is higher during traveling than before starting traveling, and the air pressure that was below the alarm threshold before starting traveling may be greater than or equal to the alarm threshold after starting traveling. In this case, notification by the notification unit is performed before the start of traveling, but notification by the notification unit is stopped by performing traveling.

  An object of the present invention is to provide a tire air pressure detection device, a tire air pressure monitoring device, and a tire air pressure monitoring system that can suppress switching between notification of a notification unit and notification stop according to a temperature change accompanying traveling. It is in.

  A tire air pressure detection device that solves the above-described problem is a tire that causes a notification unit to notify when the tire air pressure is less than an alarm threshold and the vehicle traveling time has passed a predetermined set time. A tire air pressure detecting device for transmitting a transmission signal including the tire air pressure data to an air pressure monitoring device, including a pressure sensor for detecting the tire air pressure, and the tire air pressure data detected by the pressure sensor. A transmission unit that transmits a transmission signal to the tire pressure monitoring device, a travel detection unit that detects travel of the vehicle, and a travel time that measures the travel time of the vehicle detected by the travel detection unit as travel time The transmission signal is transmitted at the first transmission frequency until the low-frequency transmission time when the traveling time of the vehicle and the vehicle is earlier than the set time. And a control unit that causes the transmission unit to perform transmission frequency variable transmission that transmits the transmission signal at a second transmission frequency that is higher than the first transmission frequency from the low frequency transmission time to the set time. And comprising.

  The temperature inside the tire rises as the vehicle travels, and the tire air pressure rises accordingly. The tire pressure monitoring device considers that the air pressure may exceed the alarm threshold by the set time until the running time has passed the set time, and notifies the notification section. Don't do it. In addition, when the traveling time reaches the set time, the tire pressure monitoring device performs notification by the notification unit if the most recently received tire pressure is less than the alarm threshold value. The tire pressure detection device temporarily sets the transmission frequency of the transmission signal to the high frequency (second transmission frequency) between the low frequency transmission time and the set time, that is, immediately before the set time. For this reason, it becomes easy for the tire pressure monitoring device to receive the transmission signal by the tire pressure detection device. Therefore, the tire pressure monitoring device cannot receive the transmission signal and the notification by the notification unit is suppressed even though the tire pressure exceeds the alarm threshold before the set time. As a result, switching between notification by the notification unit and notification stop due to a temperature change in the tire accompanying traveling is suppressed.

  The tire pressure detection device includes a wheel side temperature sensor that detects a temperature in the tire, and the control unit detects a temperature in the tire that is detected by the wheel side temperature sensor is lower than a low temperature threshold. The transmission unit performs the transmission frequency variable transmission.

  The switching between notification and notification stop due to temperature change in the tire accompanying traveling occurs when the environmental temperature is extremely low, such as in cold regions and winter. For this reason, the temperature which can determine whether environmental temperature is low temperature is set as a low temperature threshold, so that notification and notification stop are switched, and it is determined whether environmental temperature is low temperature. Then, only when the environmental temperature is determined to be low, by performing transmission frequency variable transmission, power consumption is higher than when transmitting signals with high frequency (second transmission frequency) even when the temperature is not low. Can be reduced.

  For the tire air pressure detection device, the control unit, when the travel detection unit detects the travel of the vehicle after the time that the travel of the vehicle has not been continuously detected exceeds a predetermined time, The transmission frequency variable transmission is performed again.

  When the vehicle stops for a long time, the temperature inside the tire that has risen due to traveling decreases due to the environmental temperature. For this reason, if the time when the vehicle is continuously stopped exceeds a predetermined time, it is considered that there is a possibility of switching between notification by the notification unit and notification stop when traveling is resumed, and transmission frequency variable transmission Let's try again. Thereby, when the running and stop of the vehicle are repeated, it is suppressed that the notification by the notification unit and the notification stop are repeated.

  A tire air pressure monitoring device that solves the above-described problems is a tire air pressure monitoring device that receives a transmission signal including tire air pressure data transmitted from a tire air pressure detection device provided on each wheel of the vehicle and monitors the tire air pressure. It is a monitoring device, and includes a reception unit that receives the transmission signal, a reception side travel detection unit that detects the travel of the vehicle, and a time during which the vehicle travel is detected by the reception side travel detection unit. A reception-side travel time measurement unit that measures as a reception side control unit that can cause a notification unit to notify when the air pressure received by the reception unit is below an alarm threshold, and the reception Even if the air pressure is less than the alarm threshold, the side control unit does not notify the notification unit until the traveling time has passed a predetermined set time.

  The temperature inside the tire rises as the vehicle travels, and the tire air pressure rises accordingly. For this reason, even if the tire air pressure is less than the alarm threshold until the running time reaches the set time, it is assumed that the tire air pressure may exceed the alarm threshold by the set time, and the notification unit is notified. Do not do. For this reason, when the tire air pressure is below the alarm threshold, switching between the notification by the notification unit and the notification stop is suppressed compared to the tire pressure monitoring device that performs the notification by the notification unit regardless of the travel time. .

  In the tire pressure monitoring device, when the traveling time has passed the set time, the receiving side control unit causes the notification unit to notify when the recently received air pressure is below the alarm threshold.

According to this, when the set time elapses, the notification by the notification unit can be promptly performed.
In the tire pressure monitoring device, the receiving side control unit, when the air pressure received by the receiving unit is less than a low pressure threshold set lower than the alarm threshold, regardless of the traveling time, the notification unit To inform.

  According to this, the threshold value for making a notification part perform alerting | reporting is set in multiple steps. For this reason, as a low-pressure threshold value, it is possible to perform notification by the notification unit even before the travel time has passed the set time by setting a threshold value that is preferably notified to the notification unit regardless of the surrounding environment.

  With respect to the tire pressure monitoring device, when the temperature detected by the outside air temperature sensor that detects the outside air temperature is less than the low temperature threshold for outside air temperature, the reception side control unit is until the traveling time has passed the set time. Even if the air pressure is less than the alarm threshold, the notification unit is not notified.

  According to this, similar to the tire pressure detection device, the tire pressure monitoring device also notifies the notification section until the set time elapses only when the environmental temperature is determined to be low enough to cause a change between notification and notification stop. Do not do. For this reason, when the outside air temperature is equal to or greater than the low temperature threshold for outside air temperature, the notification is performed without waiting for the set time to elapse, so that the notification can be promptly performed when the air pressure is less than the alarm threshold.

  A tire air pressure monitoring system that solves the above-described problems includes a tire air pressure detection device according to any one of claims 1 to 3 and a tire according to any one of claims 4 to 7. An air pressure monitoring device.

  ADVANTAGE OF THE INVENTION According to this invention, the switching of the alerting | reporting part according to the temperature change accompanying driving | running | working and alerting | reporting stop can be suppressed.

1 is a schematic configuration diagram of a vehicle equipped with a tire pressure monitoring system. The schematic block diagram of the transmitter in embodiment. (A) And (b) is a time chart which shows the measurement aspect of the travel time in embodiment. (A) is a time chart showing the temperature detected by the wheel side temperature sensor, (b) is a time chart showing the tire air pressure detected by the pressure sensor, and (c) is when the temperature in the tire is below the low temperature threshold. (D) is a time chart showing the temperature detected by the vehicle body side temperature sensor, (e) is the tire air pressure from the running detection to the set time. A time chart showing whether or not the receiver performs notification by the notification unit when it fluctuates across the alarm threshold, (f) is when the tire air pressure fluctuates across the alarm threshold from the travel detection to the set time The time chart which shows whether the receiver of a comparative example performs alerting | reporting by an alerting | reporting part. (A) is a time chart showing the tire air pressure detected by the pressure sensor, (b) is a time chart showing the transmission frequency of the transmission signal transmitted from the transmission circuit when the temperature inside the tire is lower than the low temperature threshold, c) is a time chart showing whether or not the receiver performs notification by the notification unit when the tire air pressure is maintained below the alarm threshold from the detection of traveling to the set time. (A) is a time chart showing the temperature detected by the wheel side temperature sensor, (b) is a time chart showing the tire air pressure detected by the pressure sensor, and (c) is when the temperature inside the tire is equal to or higher than a low temperature threshold. (D) is a time chart showing the temperature detected by the vehicle body side temperature sensor, (e) is the outside air temperature detected by the vehicle side temperature sensor. The time chart which shows whether a receiver performs alerting | reporting by an alerting | reporting part when it is more than an external temperature threshold value. (A) is a time chart showing the tire air pressure detected by the pressure sensor in the modified example, (b) is the transmission frequency of the transmission signal transmitted from the transmission circuit when the temperature in the tire in the modified example is lower than the low temperature threshold. (C) is a time chart which shows whether the receiver in a modification performs alerting | reporting by an alerting | reporting part.

Hereinafter, an embodiment of a tire pressure detection device, a tire pressure monitoring device, and a tire pressure monitoring system will be described.
As shown in FIG. 1, the vehicle 11 includes four wheels 12 in which tires 14 are mounted on wheels 13. The vehicle 11 is equipped with a control device 15 that comprehensively controls the operation of the vehicle 11 such as starting and stopping the engine. The control device 15 is connected to an ignition switch 16 that allows the driver of the vehicle 11 to start and stop the engine, and a speedometer 17 that detects the traveling speed of the vehicle 11.

  The vehicle 11 is equipped with a tire pressure monitoring system 10. The tire pressure monitoring system 10 includes a transmitter 20 as a tire pressure detection device attached to each of four wheels 12 of the vehicle 11 and a receiver 40 as a tire pressure monitoring device installed on the vehicle body of the vehicle 11. ing.

  The transmitter 20 is attached so as to be disposed in the internal space of the tire 14. Each transmitter 20 detects the air pressure of the corresponding tire 14 and wirelessly transmits a transmission signal including air pressure data indicating the detected air pressure of the tire 14.

  As shown in FIG. 2, each transmitter 20 includes a pressure sensor 21, a wheel side temperature sensor 22, an acceleration sensor 23, a controller 24, a transmission circuit 25, a transmission antenna 26, and a battery 27. The transmitter 20 operates by supplying power from the battery 27. The controller 24 as a control unit controls the operation of the transmitter 20 in an integrated manner. The pressure sensor 21 detects the pressure in the corresponding tire 14 (air pressure of the tire 14), and outputs the air pressure data of the tire 14 obtained by the detection to the controller 24. The wheel side temperature sensor 22 detects the temperature in the corresponding tire 14 (temperature in the tire), and outputs temperature data in the tire 14 obtained by the detection to the controller 24. The acceleration sensor 23 detects the acceleration acting on itself by rotating integrally with the wheel 12 and outputs the detected acceleration to the controller 24. In the present embodiment, the acceleration sensor 23 detects the acceleration in the direction in which the centrifugal force acts as the wheel 12 rotates.

  The controller 24 includes a CPU 24a, a storage unit 24b (RAM, ROM, etc.), a microcomputer including a timer, and the like, and an ID code that is identification information unique to each transmitter 20 is registered in the storage unit 24b. . This ID code is information used to identify each transmitter 20 at the receiver 40.

  The controller 24 outputs air pressure data and data including an ID code to a transmission circuit 25 as a transmission unit. The transmission circuit 25 modulates data from the controller 24 to generate a transmission signal as a modulation signal, and wirelessly transmits the transmission signal from the transmission antenna 26.

  As shown in FIG. 1, the receiver 40 includes a reception controller 41, a reception circuit 42, and a reception antenna 43. A display controller 44, an alarm device 45, and a vehicle body side temperature sensor 46 are connected to the reception controller 41 of the receiver 40. The reception controller 41 includes a CPU 41a, a reception-side storage unit 41b (ROM, RAM, etc.), a microcomputer including a timer, and the like. The reception-side storage unit 41b stores a program for comprehensively controlling the operation of the receiver 40. Has been. The receiving circuit 42 as a receiving unit demodulates a transmission signal received from each transmitter 20 through the receiving antenna 43 and sends the demodulated signal to a receiving controller 41 as a receiving side control unit.

  The vehicle body side temperature sensor 46 detects the outside air temperature. The vehicle body side temperature sensor 46 may be a temperature sensor provided in the vehicle 11 or a temperature sensor provided in the receiver 40. When a temperature sensor provided in the vehicle 11 is used as the vehicle body side temperature sensor 46, the outside air temperature detected by the temperature sensor may be acquired via the control device 15.

  The reception controller 41 grasps the air pressure of the tire 14 corresponding to the transmission source transmitter 20 based on the transmission signal from the reception circuit 42. The reception controller 41 causes the display 44 to display information related to the air pressure of the tire 14.

  The reception controller 41 further informs the driver of an abnormality in the air pressure of the tire 14 by an alarm device 45. The reception controller 41 determines whether or not the air pressure of the tire 14 ascertained from the received air pressure data is less than an alarm threshold, and if it is less than the alarm threshold, it is determined that an abnormality has occurred in the tire 14. The alarm threshold value is set to a value that can notify the driver that the tire 14 has an excessively decreased air pressure before the tire 14 has an excessively decreased air pressure. As the alarm device 45, for example, a device for notifying abnormality by lighting or blinking of light or a device for notifying abnormality by sound is applied. Therefore, in this embodiment, the alarm device 45 serves as a notification unit that notifies the driver.

  As described above, when the air pressure of the tire 14 is less than the alarm threshold value, the reception controller 41 performs notification by the alarm device 45, but the air pressure of the tire 14 varies in proportion to the temperature in the tire 14. The temperature in the tire 14 increases in accordance with the generation of frictional heat accompanying the traveling of the vehicle 11, and the air pressure of the tire 14 also increases accordingly. For this reason, when the air pressure of the tire 14 becomes less than or equal to the alarm threshold due to a change in the temperature in the tire 14 due to the traveling of the vehicle 11, notification by the alarm device 45 and notification stop are switched. Although this operation is a normal operation as the tire air pressure monitoring system 10, it is difficult for the driver to determine whether or not an abnormality has occurred in the tire 14 by repeating the notification and the notification stop. For this reason, in this embodiment, it is suppressed that the alerting | reporting by the alarm device 45 and alerting | reporting stop are repeated by performing the following processes.

  As shown in FIGS. 3A and 3B, the controller 24 determines whether the vehicle 11 is running or stopped based on the acceleration input from the acceleration sensor 23. More specifically, since the centrifugal acceleration acting on the acceleration sensor 23 increases as the vehicle 11 travels, the acceleration sensor 23 detects when the vehicle 11 is stopped in consideration of the tolerance of the acceleration sensor 23. A value higher than the acceleration to be set is set as the threshold value for travel determination. Then, the controller 24 determines that the vehicle 11 is traveling when the acceleration detected by the acceleration sensor 23 is greater than or equal to the travel determination threshold.

  The controller 24 measures the time when the acceleration detected by the acceleration sensor 23 is equal to or greater than the travel determination threshold as travel time. As shown in FIG. 3B, when the acceleration detected by the acceleration sensor 23 becomes equal to or greater than the travel determination threshold at time t11, the controller 24 starts measuring travel time. When the acceleration detected by the acceleration sensor 23 becomes less than the travel determination threshold at time t12, the controller 24 interrupts the travel time measurement. When the acceleration detected by the acceleration sensor 23 is less than the travel determination threshold, the controller 24 measures the time during which the acceleration is less than the travel determination threshold as the stop time.

  The controller 24 can determine that the vehicle 11 is stopped when the acceleration detected by the acceleration sensor 23 is less than the travel determination threshold. When the vehicle 11 stops, if the vehicle 11 is temporarily stopped by a traffic light or the like, it can be considered that the vehicle 11 continues to travel, and if the vehicle 11 is stopped for a long time by parking in a parking lot or the like, the traveling is ended. Can be considered as The temperature in the tire 14 is increased due to frictional heat caused by the traveling of the vehicle 11, but if the vehicle is temporarily stopped by a traffic light or the like, the traveling is resumed in a short time, There is little effect on temperature. On the other hand, when the stop time of the vehicle 11 is long, the temperature in the tire 14 that has risen due to traveling decreases due to heat exchange with the environmental temperature.

  The controller 24, when the vehicle 11 resumes traveling at time t13 before the stop time of the vehicle 11 exceeds the predetermined time (when the acceleration detected by the acceleration sensor 23 is equal to or greater than the traveling determination threshold), The travel time measurement is restarted from the time when the travel time measurement is interrupted. On the other hand, if the time when the vehicle 11 stops at time t14 and the vehicle 11 continues to stop at time t15 (stop time) exceeds a predetermined time, the controller 24 keeps the vehicle 11 for a long time. Therefore, it is considered that the temperature in the tire 14 has decreased, and the running time is reset. That is, when the time when the vehicle 11 is continuously stopped exceeds a predetermined time, the travel time is measured from 0 at the next travel (time t16). In the present embodiment, as the predetermined time, a time that can be considered that the vehicle 11 is temporarily stopped is set. In the present embodiment, the acceleration sensor 23 serves as a travel detection unit, and the controller 24 serves as a travel time measurement unit.

  Similar to the controller 24 of the transmitter 20, the reception controller 41 of the receiver 40 measures the travel time. Specifically, the receiver 40 acquires the speed of the vehicle 11 detected by the speedometer 17 via the control device 15, and the time when the speed of the vehicle 11 becomes equal to or higher than the threshold speed is set as the travel time. The time when the speed of the vehicle 11 is less than the threshold speed is measured as the stop time. As the threshold speed, for example, the acceleration detected by the acceleration sensor 23 is set to a speed that is equal to or higher than the travel determination threshold. Thereby, the travel time measured by the transmitter 20 and the travel time measured by the receiver 40 are made to coincide. In practice, there is a difference between the travel time measured by the transmitter 20 and the travel time measured by the receiver 40 due to the tolerance of each member of the transmitter 20 and the receiver 40. For convenience, the description will be made assuming that they are the same. In the present embodiment, the reception controller 41 that detects the travel of the vehicle 11 from the speed of the speedometer 17 and measures the travel time is the reception-side travel detection unit and the reception-side travel time measurement unit.

  When the acceleration detected by the acceleration sensor 23 is greater than or equal to the travel determination threshold, that is, when the vehicle 11 is traveling, the controller 24 periodically transmits a transmission signal from the transmission circuit 25. At this time, the controller 24 causes the transmission circuit 25 to perform transmission frequency variable transmission for changing the transmission frequency according to the travel time. Details will be described below.

  As shown in FIGS. 4A and 4B, as the vehicle 11 travels, the temperature inside the tire 14 increases, and the air pressure of the tire 14 also increases accordingly. Moreover, as shown in FIG.4 (c), when the vehicle 11 starts driving | running | working, the controller 24 of the transmitter 20 will transmit a transmission signal with 1st transmission frequency. Transmission of the transmission signal at the first transmission frequency is performed until the traveling time reaches a predetermined low frequency transmission time t1. When the traveling time passes the low-frequency transmission time t1, the controller 24 acquires the temperature in the tire 14 detected by the wheel-side temperature sensor 22. And if the temperature in the tire 14 is less than a low temperature threshold value, transmission frequency will be switched so that a transmission signal may be transmitted with 2nd transmission frequency. The second transmission frequency is higher than the first transmission frequency. In addition, high frequency may increase the frequency | count of transmitting a transmission signal itself, and may increase the number of the frames transmitted at once. Transmission of the transmission signal at the second transmission frequency is performed from the low frequency transmission time t1 to the set time t2. When the traveling time reaches the set time t2, the transmission signal is transmitted at a frequency lower than the second transmission frequency. In this embodiment, this transmission frequency is the same as the first transmission frequency. The set time t2 is a predetermined time, for example, a time determined based on the laws and regulations of each country. According to the laws and regulations of each country, when an abnormality occurs in the air pressure of the tire 14 according to each country, it is determined by when the notification should be performed from the start of traveling. The set time t2 is set to a time at which notification should be performed or a time slightly shorter than this time. The low frequency transmission time t1 is earlier than the set time t2, and when the transmission signal is transmitted at the second transmission frequency, the receiver 40 can receive the transmission signal by the set time t2. Is set to the estimated time.

  The low temperature threshold is set to a temperature at which it can be determined whether the environmental temperature is low enough to switch between notification and notification stop. It is considered that the air pressure of the tire 14 is less than the alarm threshold value due to the influence of the environmental temperature because it is considered to be an environment such as a cold region or winter, so the temperature is detected by the wheel side temperature sensor 22 to determine whether the environmental temperature is low. Deciding.

  The reception controller 41 of the receiver 40 recognizes the air pressure of the tire 14 by receiving the transmission signal. As shown in FIG. 4D, similarly to the transmitter 20, the receiver 40 determines whether or not the environmental temperature is low enough to cause the alarm device 45 to switch between notification and notification stop. When the outside air temperature detected by the temperature sensor 46 is less than the outside air temperature low temperature threshold, the notification is not performed until the set time t2 has elapsed. Note that the low temperature threshold for outside air temperature is set to a value similar to the low temperature threshold.

In FIG.4 (b), the air pressure of the tire 14 is more than an alarm threshold value at the time t3 which is the time between the low frequency transmission time t1 and the setting time t2.
As shown in FIG. 4 (e), the receiver 40 does not notify the alarm device 45 until the set time t2, so even if the air pressure received before the time t3 is less than the alarm threshold value, the alarm device 45. Do not let the notification by. Further, since the air pressure is equal to or higher than the alarm threshold at the set time t2, the receiver 40 does not notify the alarm device 45. When the traveling time reaches the set time t2, the receiver 40 determines whether or not to cause the alarm device 45 to perform notification according to the latest received air pressure. If the receiver 40 cannot receive a transmission signal transmitted after time t3 due to the influence of the communication environment or the like by the set time t2, the receiver 40 warns by the air pressure received before time t3. In order to determine whether or not the alarm device 45 is to be notified, the alarm device 45 is to be notified. In the present embodiment, the transmission signal is transmitted at a high frequency between the low frequency transmission time t1 and the set time t2 in order to suppress the switching between the notification and the notification stop due to the inability to receive the transmission signal. .

  As shown in FIG. 4 (f), as a comparative example, a receiver is assumed that, when air pressure less than the alarm threshold is received, the alarm device 45 is notified regardless of the travel time. The receiver of the comparative example causes the alarm device 45 to notify when it receives an air pressure less than the alarm threshold. Then, when the air pressure of the tire 14 becomes equal to or higher than the alarm threshold due to the temperature increase in the tire 14 as the vehicle 11 travels, the notification by the alarm device 45 is stopped. For this reason, the notification by the alarm device 45 and the notification stop are switched.

  As shown in FIGS. 5A to 5C, when the set pressure t <b> 2 has elapsed and the air pressure of the tire 14 most recently received by the receiver 40 is less than the alarm threshold, the receiver 40 is connected to the alarm 45. To inform. For this reason, when the traveling time reaches the set time t2, the alarm device 45 promptly notifies.

  As shown in FIG. 6A to FIG. 6C, when the temperature in the tire 14 detected by the wheel side temperature sensor 22 is equal to or higher than the low temperature threshold, the transmitter 20 Send at the sending frequency. That is, when the temperature in the tire 14 is equal to or higher than the low temperature threshold, it is considered that the environmental temperature is not so low that switching between notification and notification stop occurs, and the transmission signal is not transmitted frequently before the set time t2. .

  In addition, as shown in FIGS. 6D and 6E, the receiver 40 determines that the running time when the outside air temperature detected by the vehicle body side temperature sensor 46 is equal to or higher than the outside temperature low temperature threshold. Regardless, when an air pressure less than the alarm threshold is received, the alarm device 45 is notified.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) The transmitter 20 transmits the transmission signal at the first transmission frequency during the travel time until the low frequency transmission time t1, and from the low frequency transmission time t1 to the set time t2 than the first transmission frequency. The transmission signal is transmitted at a high second transmission frequency. That is, the transmission signal is transmitted with high frequency immediately before the set time t2 elapses. When the traveling time reaches the set time t2, the receiver 40 determines whether or not to cause the alarm device 45 to perform notification according to the most recently received air pressure data. By temporarily increasing the transmission frequency of the transmission signal between the low frequency transmission time t1 and the set time t2, the reception circuit 42 can easily receive the transmission signal. Therefore, the alarm device 45 is notified when the set time t2 has elapsed because the receiver 40 cannot receive a transmission signal even though the air pressure of the tire 14 has exceeded the alarm threshold before the set time t2. Is suppressed. For this reason, it is suppressed that the alerting | reporting by the alarm device 45 and a notification stop are switched by the temperature change in the tire 14 accompanying driving | running | working.

(2) Moreover, since the receiver 40 receives the transmission signal, the power consumption is reduced as compared with the case where the transmission signal is always transmitted with high frequency.
(3) The transmitter 20 performs transmission frequency variable transmission when the temperature in the tire 14 detected by the wheel side temperature sensor 22 is less than the low temperature threshold. Switching between notification and notification stop due to a temperature change in the tire 14 associated with traveling occurs when the environmental temperature is extremely low, such as in a cold region or winter. For this reason, a low temperature threshold is set, and transmission frequency variable transmission is performed when the environmental temperature is low enough to cause switching between notification and notification stop. Since the transmission frequency variable transmission is not performed except in a cold district or in winter, power consumption due to the transmission signal being transmitted frequently is reduced.

  (4) When the vehicle 11 stops for a long time, the temperature in the tire 14 that has risen due to traveling is cooled by the surrounding environment. For this reason, when the time when the vehicle 11 is continuously stopped exceeds a predetermined time or longer, it is considered that there is a possibility that the alarm 45 switches between notification and notification stop, and the travel time is reset. Thereby, transmission frequency variable transmission can be performed again. Therefore, when the traveling and stopping of the vehicle 11 are repeated, it is possible to suppress the notification by the alarm device 45 and the notification stop being repeated.

  (5) The receiver 40 does not notify the alarm device 45 even if the received air pressure is less than the alarm threshold until the traveling time reaches the set time t2. Therefore, when the air pressure of the tire 14 exceeds the alarm threshold by the set time t2 due to the traveling of the vehicle 11, the alarm device 45 does not notify, so the alarm device 45 switches between notification and notification stop. Is suppressed.

  (6) When the travel time reaches the set time t2, the reception controller 41 causes the alarm device 45 to notify when the latest received air pressure is less than the alarm threshold. For this reason, it is possible to promptly notify when the traveling time reaches the set time t2.

  (7) When the outside air temperature is lower than the low temperature threshold value for the outside air temperature, the receiver 40 causes the alarm device 45 to make a notification regardless of the travel time when receiving the air pressure below the alarm threshold value. For this reason, when the environmental temperature is not low enough to cause switching between notification and notification stop, notification can be promptly performed.

  (8) Changing the transmission frequency according to the travel time and determining whether the alarm device 45 is to be notified according to the travel time are stored in the storage unit 24b and the reception-side storage unit 41b. It is executed by the program. Therefore, switching between notification and notification stop can be suppressed only by changing the software without changing the hardware of the transmitter 20 or the receiver 40.

In addition, you may change embodiment as follows.
As shown in FIGS. 7A to 7C, a low pressure threshold may be set in addition to the alarm threshold as a threshold for causing the alarm device 45 to issue an alarm. As the low-pressure threshold, a value lower than the alarm threshold is set, and is set to a value that can issue an alarm when the air pressure drops excessively. When the tire 14 air pressure indicated by the air pressure data is less than the low pressure threshold, the reception controller 41 causes the alarm device 45 to make a notification regardless of the travel time. According to this, when the air pressure of the tire 14 is so low that the fluctuation of the air pressure of the tire 14 due to the temperature change due to traveling can be ignored, this can be notified to the driver.

  -Transmission frequency variable transmission may be performed irrespective of the temperature in the tire 14 detected by the wheel side temperature sensor 22. In this case, the transmitter 20 may not be provided with the wheel side temperature sensor 22.

  In the embodiment, from the air pressure data included in the transmission signal transmitted from the transmitter 20, the receiver 40 determines whether the air pressure of the tire 14 is less than the alarm threshold. You may determine whether it is less than an alarm threshold value. When the pressure sensor 21 detects the air pressure of the tire 14, the controller 24 of the transmitter 20 determines whether the air pressure of the tire 14 is less than an alarm threshold value. Then, when the air pressure of the tire 14 is less than the alarm threshold, the transmitter 20 transmits the transmission signal including the alarm flag. When the receiver 40 receives a transmission signal including an alarm flag, the receiver 40 determines that the air pressure of the tire 14 is less than the alarm threshold. Similarly, the controller 24 of the transmitter 20 may determine whether the air pressure of the tire 14 is less than the above-described low pressure threshold.

  In the embodiment, the travel time is reset when the time when the acceleration detected by the acceleration sensor 23 is continuously less than the travel determination threshold exceeds a predetermined time, but is not limited thereto. For example, when the ignition switch 16 is turned on (or off), the transmitter 20 is notified that the ignition switch 16 is turned on (or off), and the transmitter 20 turns on (or off) the ignition switch 16. The travel time may be reset when triggered by.

  In the embodiment, the timing at which the controller 24 determines whether the temperature in the tire 14 is lower than the low temperature threshold may be at the start of traveling. Similarly, the timing at which the reception controller 41 determines whether or not the outside air temperature is less than the outside air temperature low threshold may be at the start of traveling or at the low frequency transmission time t1.

The first transmission frequency may be different from the transmission frequency of the transmission signal transmitted after the set time t2.
-You may alert | report by displaying on the indicator 44 using the indicator 44 as an alerting | reporting part. In addition, the notification unit may be a member different from the member provided in the vehicle body, for example, a portable terminal owned by the driver.

  -The temperature data in the tire 14 may be included in the transmission signal. In this case, the reception controller 41 recognizes the temperature in the tire 14 based on the transmission signal. When the temperature in the tire 14 is equal to or higher than the low temperature threshold, if the air pressure below the alarm threshold is received, the alarm is output regardless of the running time. The device 45 may be notified.

-You may use other than the acceleration sensor 23 as a driving | running | working detection part. For example, a shock sensor or the like may be used.
The receiving side travel detection unit is not limited to the speedometer 17. For example, the reception controller 41 as the reception-side travel detection unit may determine that the vehicle 11 is traveling while receiving a transmission signal.

  ・ If the received air pressure decreases with the passage of time or if there is no increase in air pressure commensurate with the temperature rise, the receiver 40 does not mean that the air pressure has decreased due to the influence of the environmental temperature. Therefore, the alarm device 45 may notify the user regardless of the travel time. In other words, when the receiver 40 detects that the air pressure has decreased due to the influence of the environmental temperature, such as when detecting an increase in air pressure commensurate with the temperature increase, the alarm 40 notifies the alarm until the set time t2 elapses. It is not necessary to perform.

  Further, when the air pressure detected by the pressure sensor 21 decreases with the passage of time, or when there is no increase in air pressure commensurate with the temperature rise, the transmitter 20 determines these and flags the transmission signal. May be transmitted. When the receiver 40 receives the transmission signal including the flag, the alarm device 45 is notified when the air pressure is equal to or lower than the alarm threshold value regardless of the travel time. Further, when the transmitter 20 detects an increase in air pressure commensurate with the temperature increase, the transmitter 20 may perform transmission by including a flag in the transmission signal. When receiving the transmission signal including the flag, the receiver 40 does not notify the alarm device 45 until the set time t2.

The receiver 40 may be mounted on the vehicle 11 provided with a transmitter having a constant transmission frequency.
The receiver 40 may not perform the notification by the alarm device 45 until the set time t2 has elapsed only when the vehicle 11 travels in a cold region based on the position information by the GPS of the vehicle.

The receiver 40 may determine whether or not it is a winter season from the calendar, and may not perform the notification by the alarm device 45 until the set time t2 has elapsed only in the winter season.
The receiver 40 may determine whether or not to notify the alarm device 45 until the set time t2 elapses, depending on whether or not the notification and the notification stop are switched during the past travel. For example, when the notification and the notification stop are switched during the previous travel, the notification may not be performed until the set time t2 has elapsed, and the notification and notification are performed among the most recent travelings. The determination may be made from the rate at which stop switching occurs.

  The reception controller 41 of the receiver 40 may determine whether or not the alarm device 45 is not notified until the set time t <b> 2 elapses, based on the received increase in the air pressure of the tire 14. For example, when it can be determined that the air pressure of the tire 14 is equal to or higher than the alarm threshold by the set time t2 from the increase in the air pressure of the tire 14, the alarm device 45 may not be notified until the set time t2 has elapsed. Good. Further, when the controller 24 of the transmitter 20 determines that the air pressure of the tire 14 detected by the pressure sensor 21 is equal to or higher than the alarm threshold value by the set time t2, the controller 24 may perform transmission by including a flag in the transmission signal. . In this case, when receiving a transmission signal including this flag, the receiver 40 may not cause the alarm device 45 to notify the user until the set time.

  DESCRIPTION OF SYMBOLS 10 ... Tire pressure monitoring system, 11 ... Vehicle, 12 ... Wheel, 14 ... Tire, 20 ... Transmitter, 21 ... Pressure sensor, 22 ... Wheel side temperature sensor, 23 ... Acceleration sensor, 24 ... Controller, 25 ... Transmission circuit, DESCRIPTION OF SYMBOLS 40 ... Receiver, 41 ... Reception controller, 42 ... Reception circuit, 45 ... Alarm, 46 ... Body side temperature sensor.

Claims (8)

When the tire air pressure is less than the alarm threshold value and the traveling time of the vehicle has passed a predetermined set time, the tire air pressure monitoring device is configured to notify the tire air pressure data to the tire air pressure monitoring device. A tire pressure detecting device for transmitting a transmission signal including:
A pressure sensor for detecting the air pressure of the tire;
A transmission unit for transmitting a transmission signal including the tire pressure data detected by the pressure sensor to the tire pressure monitoring device;
A travel detector for detecting travel of the vehicle;
A travel time measuring unit that measures a time during which the travel of the vehicle is detected by the travel detection unit as a travel time;
The transmission signal is transmitted at a first transmission frequency until a low-frequency transmission time in which the traveling time of the vehicle is earlier than the set time, and the first transmission is transmitted from the low-frequency transmission time to the set time. A tire air pressure detection device comprising: a control unit that causes the transmission unit to perform transmission frequency variable transmission that transmits the transmission signal at a second transmission frequency that is higher than the frequency. A wheel side temperature sensor for detecting the temperature in the tire,
The tire pressure detection device according to claim 1, wherein the control unit causes the transmission unit to perform the transmission frequency variable transmission when a temperature in the tire detected by the wheel side temperature sensor is lower than a low temperature threshold.   When the travel detection unit detects the travel of the vehicle after a time during which the travel of the vehicle has not been continuously detected by the travel detection unit exceeds a predetermined time, the control unit again performs the transmission frequency variable transmission. The tire pressure detection device according to claim 1 or 2, wherein the tire pressure detection device is performed. A tire pressure monitoring device that receives a transmission signal including tire pressure data transmitted from a tire pressure detection device provided on each wheel of a vehicle and monitors the tire pressure,
A receiver for receiving the transmission signal;
A receiving side travel detector for detecting travel of the vehicle;
A reception side travel time measuring unit that measures the time during which the vehicle travel is detected by the reception side travel detection unit as a travel time;
A receiving-side control unit capable of notifying the notifying unit when the air pressure received by the receiving unit is below an alarm threshold, and
The reception-side control unit is a tire pressure monitoring device that does not notify the notification unit even if the air pressure is less than the alarm threshold until the travel time has passed a predetermined set time.   The tire pressure monitoring according to claim 4, wherein when the traveling time has passed a set time, the receiving side control unit causes the notification unit to notify when the recently received air pressure is below the alarm threshold. apparatus.   The receiving side control unit, when the air pressure received by the receiving unit is less than a low pressure threshold value set lower than the alarm threshold value, causes the notification unit to perform notification regardless of the travel time. The tire pressure monitoring device according to claim 4 or 5.   When the temperature detected by the outside air temperature sensor that detects the outside air temperature is less than the low temperature threshold for outside air temperature, the air pressure remains at the alarm threshold until the travel time has passed the set time. The tire pressure monitoring device according to any one of claims 4 to 6, wherein the notification unit is not notified even if the temperature is less than the value. The tire pressure detection device according to any one of claims 1 to 3,
A tire pressure monitoring system comprising: the tire pressure monitoring device according to any one of claims 4 to 7.