JP2005199977A - Vehicular tire state monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the power consumption of a detector by suppressing the operation of the detector in a tire to a irreducible minimum in a tire condition monitoring system in which the detector to detect the tire state such as the air pressure and transmit it to a monitor is assembled in the tire, and the tire state of a vehicle is monitored at the monitoring device side. <P>SOLUTION: In the system, a monitoring device successively transmits the starting signal for power supply to a detector in each tire via a transmitter provided on each tire of a vehicle (110), each detector in the tire generates the power supply voltage for starting by the starting signal, and detects the tire state (the air pressure and the temperature), and transmits the result of detection. The monitoring device receives the detection data to monitor the state of all the tires mounted on a vehicle (120, 130). The monitoring device performs the monitoring (200) of transmitting the re-starting signal to the tire from which the detection data cannot be acquired after transmitting the starting signal, and acquiring the detection data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a plurality of detection devices that detect the state (air pressure, etc.) of a plurality of tires mounted on a vehicle and transmit them wirelessly, and by receiving a transmission signal from each detection device, the tire state of each tire is determined. The present invention relates to a vehicle tire condition monitoring system including a monitoring device for monitoring.

  Conventionally, in a vehicle equipped with an air-injection type tire, in order to enhance safety during traveling, the tire condition such as air pressure and temperature is detected for each tire mounted on the vehicle, and the detection result is wirelessly transmitted. There is known a tire condition monitoring system that incorporates a detection device that transmits data and receives a transmission signal from the detection device on the monitoring device side, which is a vehicle-mounted device, so that the state of each tire can be automatically monitored. .

  As this tire condition monitoring system, generally, a configuration in which each detection device in a tire is periodically activated to transmit tire information is known. Since the detection device operates independently regardless of the operation state, there is a problem that the power consumption of the detection device becomes unnecessarily large, and a battery with a large capacity must be incorporated in the tire.

  On the other hand, in order to solve such a problem, when driving of the vehicle is started, the monitoring device transmits an operation start signal to each detecting device to start each detecting device, and when the driving of the vehicle is stopped, monitoring is performed. There has been proposed a monitoring system in which the operation of each detection device is stopped by the device transmitting an operation stop signal to each detection device (see, for example, Patent Document 1).

And according to this proposed monitoring system, since the detection device in each tire can be operated only during driving of a vehicle that requires monitoring of the tire condition, the power consumption of each detection device is reduced, The capacity of the battery incorporated in each tire can be reduced.
JP 2001-250186 A

  However, although the proposed monitoring system can operate the detection device in the tire only during the driving of the vehicle, each detection device operates continuously during the driving of the vehicle. There was a problem that power consumption could not be reduced sufficiently.

  In other words, in the monitoring system proposed above, when the detection device receives the operation start signal from the monitoring device side, the detection device periodically detects the tire state such as the air pressure until the operation stop signal is received. The operation mode for transmitting the result is entered. In this operation mode, even when the tire condition is not detected or transmitted, the standby current flows, so the power consumption by the detection device cannot be reduced sufficiently. is there.

  The present invention has been made in view of such problems, and a detection device that detects a tire state such as air pressure and transmits a detection result to a monitoring device is incorporated in the tire of the vehicle, and the detection device on the monitoring device side that is an in-vehicle device. In the tire condition monitoring system that monitors the tire condition by receiving the transmission signal from the vehicle, the operation of the detection device incorporated in the tire is minimized and the power consumption on the detection device side is reduced. The purpose is to do.

  In the tire condition monitoring system of the present invention (specifically, described in claim 1) made to achieve such an object, a plurality of detection devices incorporated in each tire of a vehicle are respectively provided with air pressures in each tire. Is detected, the detection result is transmitted wirelessly, and the monitoring device receives the detection result from each transmitted detection device to monitor the state of each tire, and the monitoring result ( Notify the occupant of the air pressure of each tire and the decrease in air pressure).

  Further, in the vicinity of each tire, transmission means for wirelessly transmitting an activation signal to the detection device in each tire is arranged, and the monitoring means causes the transmission signal to be transmitted from each of these transmission means. Thus, each of the detection devices is activated, and then the tire condition of each tire is monitored by receiving the detection result transmitted from each of the detection devices. Each detection unit is activated by receiving an activation signal transmitted from a nearby transmission unit, detects a tire condition and transmits a detection result, and then stops operation.

  That is, in the tire condition monitoring system of the present invention, a communication system is configured in which the monitoring device is a master and the detection device in each tire is a slave, and each detection device has transmission means corresponding to each detection device. Only when the activation signal transmitted from the monitoring device side is received, the tire condition is detected and the detection result is transmitted.

  Therefore, on the monitoring device side, it becomes possible to operate each detection device only when it is necessary to acquire the tire state such as air pressure from each detection device, and the operation of each detection device is minimized. The amount of power consumed by each detection device can be sufficiently reduced.

  Therefore, according to the present invention, when a battery is incorporated as a power source for operating the detection device in each tire of the vehicle, it is possible to reduce the capacity of the battery or extend the life of the battery. It becomes.

  Further, in the tire condition monitoring device of the present invention, it is only necessary to activate the detection device in each tire when necessary to monitor the condition of each tire on the monitoring device side. It is not necessary to operate the detection device.

  Therefore, as described in claim 2, the tire condition monitoring device according to the present invention is a long wave (LF) having a frequency of about 30 kHz to 300 kHz as a start signal from a transmission unit arranged corresponding to each detection device. Each detection device is provided with a power supply circuit that generates a power supply voltage by rectifying the activation signal, and the detection device is activated when the power supply voltage is generated by the power supply circuit. Then, the tire state may be detected and the detection result may be transmitted.

  In this way, it is not necessary to incorporate a battery in each tire as a power source for the detection device, and it is possible to prevent the detection device from becoming inoperable due to battery consumption. Costs can be reduced and system reliability can be improved.

  By the way, in the tire condition monitoring system of the present invention, the monitoring device receives the transmission signal (the detection result of the tire condition) from each detection device incorporated in the plurality of tires of the vehicle, thereby determining the condition of each tire. Since it is to be monitored, it is necessary to be able to receive a transmission signal from each detection device.

  For this purpose, as described in claim 3, a single reception unit common to each detection device is provided, and the monitoring device transmits a transmission signal from each detection device via the one reception unit. By receiving, the detection result of the tire condition by each detection device may be acquired, or, as described in claim 5, a transceiver comprising a transmission means and a reception means is provided for each tire. Provided on the monitoring device side is to acquire a transmission signal (detection result of the tire condition) from the detection device of each tire via a receiving means in a transceiver arranged in the vicinity of the tire in which the detection device is incorporated. It may be.

  In particular, as described in claim 3, when the monitoring device is configured to acquire the detection result of the tire state transmitted from each detection device via the receiving means common to each detection device. As described in claim 4, the detection device in each tire uses a radio signal of an ultrahigh frequency (VHF, frequency: 30 MHz to 300 MHz) or an ultrahigh frequency (UHF, frequency: 300 MHz to 3 GHz) as a result of detecting the tire condition. It is good to comprise so that it may transmit.

  This is because the ultra-high frequency to ultra-high frequency MHz band radio wave can secure the reach with less transmission power than the long wave and other kHz band radio wave (in other words, the detection device detects the tire condition) The power consumption required to transmit the signal is reduced), and the signal is reflected by a shield existing between the vehicle-side monitoring device, such as a microwave wave such as a microwave, and transmitted from the detection device. This is because it is possible to prevent the signal from reaching the receiving means on the monitoring device side.

  Further, as described in claim 5, a transmitter / receiver is provided for each tire, and on the monitoring device side, the detection result of the tire state transmitted from the detection device in each tire is displayed in the transmitter / receiver corresponding to each tire. When it is configured to acquire via the receiving means, the detection device in each tire and each transceiver corresponding thereto may be configured as described in claim 6.

  That is, as described in claim 6, the detection device in each tire and each transceiver corresponding thereto have a transmission / reception antenna that transmits and receives a long wave (LF) signal having a frequency of about 30 kHz to 300 kHz. In the transmitter / receiver, the transmission means transmits a long-wave band signal as an activation signal via a transmission / reception antenna, and the reception means receives a transmission signal from a detection device in an adjacent tire via the transmission / reception antenna, The reception signal is configured to be output to the monitoring device, and each detection device is provided with a power supply circuit that generates a power supply voltage by rectifying the activation signal received from the transmission means by the transmission / reception antenna. Each detection device is activated when the power supply voltage is generated by this power supply circuit, detects the tire condition, and wirelessly transmits the detection result via the transmission / reception antenna. It may be configured to so that.

  That is, in this way, as in the tire condition monitoring system according to claim 2 described above, it is not necessary to incorporate a battery in each tire as a power source for the detection device, and the detection device cannot be operated due to battery consumption. It is possible to transmit the tire condition detected by each detection device to the monitoring device side using the antenna for starting signal transmission / reception while preventing the Cost can be further reduced.

  In this case, a long-wave (LF) band signal is used not only for supplying power to the detection device but also for transmitting the tire condition detection result from the detection device to the monitoring device. The distance between the detection device that transmits and receives the tire condition detection result and the transmitter / receiver is very short, so that the detection device detects the tire condition detection result. It is possible to sufficiently reduce the amount of power required to transmit.

  Next, when a transmitter / receiver is provided for each tire as in the tire condition monitoring system according to claim 5 or 6, transmission signals from each detection device may interfere with each transmitter / receiver. If the transmission power of each detection device is set so that there is no occurrence, the detection result of the tire state may be transmitted simultaneously from each detection device, but the tire state monitoring system according to claim 3 or 4 Thus, when the transmission signal from each detection device is received via one receiving means common to each detection device, the detection result of the tire condition is simultaneously transmitted from each detection device. It is necessary not to.

And in order to prevent that the detection result of a tire condition is simultaneously transmitted from each detection apparatus in this way, it is good to comprise a monitoring apparatus as described in Claim 7, for example.
That is, in the tire condition monitoring system according to claim 7, the monitoring device causes the detection device in each tire to be individually activated by transmitting activation signals at different timings from the respective transmission means, and then the activated detection is performed. The tire condition of each tire is individually monitored by individually acquiring the tire condition detection results transmitted from the apparatus.

  Therefore, according to this tire condition monitoring system, a plurality of detection devices incorporated in each tire are activated at the same time, and tire condition detection results are not transmitted simultaneously from the plurality of detection devices. The condition of each tire can be monitored individually.

  However, even if the monitoring device is configured as described in claim 7, it is considered that the detection result of the tire condition transmitted from the detection device on the monitoring device side cannot be obtained due to high-frequency noise around the vehicle or the like. In the tire condition monitoring system according to claim 7, when the monitoring device cannot acquire the tire condition detection result transmitted from the corresponding detection device after transmitting the activation signal, as described in claim 8. May be configured to acquire the tire condition detection result from the detection device by transmitting the activation signal again from the transmission means corresponding to the detection device.

  In other words, even if the detection device is activated by transmitting the activation signal, depending on the radio wave condition around the vehicle, the transmission signal from the detection device (the detection result of the tire condition) may not be obtained on the monitoring device side. In such a case, the detection result of the tire condition can be acquired by transmitting the activation signal to the detection device again.

  In this way, the monitoring device can more reliably monitor the state of each tire mounted on the vehicle, and if any tire has an abnormality, the vehicle occupant In contrast, it is possible to promptly notify that effect.

  By the way, in this case, the timing for retransmitting the activation signal to the detection device that could not acquire the tire condition detection result is set immediately after determining that the tire condition detection result could not be acquired from the detection device. However, in this way, the detection result is acquired when the detection device itself is out of order, or when the radio wave condition in the vicinity of the detection device is poor and the detection result can be acquired from another detection device. It is conceivable that a possible detection device cannot be activated.

  For this reason, in the tire condition monitoring system according to claim 8, further, as described in claim 9, the monitoring device sequentially transmits the activation signal to each transmission means, and thereafter transmits the activation signal. It is good to comprise so that a starting signal may be transmitted again from the transmission means corresponding to the detection apparatus which was not able to acquire the detection result of a tire state.

  In this way, when there is a detection device (abnormality detection device) that is not able to acquire the detection result of the tire state despite being activated by transmitting the activation signal, the other detection device mounted on the vehicle is After starting all and obtaining the detection result from the detection device, it becomes possible to retransmit the activation signal to the abnormality detection device, resulting in a delay in obtaining the tire condition from the detection device that can operate normally Can be prevented.

  In this case, when there are a plurality of abnormality detection devices that cannot acquire the tire state detection result, it is necessary to sequentially activate each abnormality detection device by transmitting an activation signal for each abnormality detection device.

  Next, in order to prevent detection results from being simultaneously transmitted from a plurality of detection devices mounted on the vehicle, it is not always necessary to configure the monitoring device as described above. For example, a tire condition monitoring system is claimed. You may comprise as described in claim | item 10.

  That is, in the tire condition monitoring system according to claim 10, each detection device is configured to transmit a tire condition detection result after a different elapsed time has elapsed after receiving the activation signal. The monitoring device simultaneously activates the detection devices by transmitting the activation signals from the transmission units, and then sequentially acquires the detection results of the tire conditions transmitted at different timings from the detection devices, Monitor the tire condition of each tire.

  Therefore, even in this tire condition monitoring system, it is possible to prevent detection results from being simultaneously transmitted from a plurality of detection devices mounted on the vehicle, and the monitoring device side individually monitors tire conditions such as air pressure for each tire. Will be able to.

  The inventions according to claims 7 to 10 described above can be applied even to a tire condition monitoring system in which a transceiver is provided for each tire as described in claim 5 or claim 6. In such a system, since the transmission signal from each detection device can be selectively received by the receiving means in the transceiver corresponding to each detection device, the monitoring device can transmit each transmission signal according to claim 11. By simultaneously starting the detection signals from the means, the respective detection devices are simultaneously activated, and thereafter, the tire state detection results transmitted from the respective detection devices via the respective reception means are individually obtained, You may comprise so that a tire state may be monitored.

  In addition, when the monitoring device is configured to simultaneously transmit the activation signal to each of the detection devices as in the tire condition monitoring system according to claim 10 or claim 11, the monitoring device further includes 12, if there is a detection device (abnormality detection device) that cannot acquire the detection result of the tire condition after transmission of the activation signal, the activation signal is transmitted again from the transmission means corresponding to the abnormality detection device. It is good to comprise so that the detection result of the tire state from an abnormality detection apparatus may be acquired by doing.

  That is, if the monitoring device is configured in this way, the state of each tire mounted on the vehicle can be more reliably monitored on the monitoring device side as in the tire condition monitoring system according to claim 8. Thus, when an abnormality occurs in any of the tires, it is possible to promptly notify the vehicle occupant to that effect.

Embodiments of the present invention will be described below.
FIG. 1 is an explanatory diagram showing the overall configuration of a tire condition monitoring system (hereinafter also simply referred to as a monitoring system) of an embodiment to which the present invention is applied.

  As shown in FIG. 1, the monitoring system of the present embodiment is an air injection type that constitutes front and rear left and right wheels (left front wheel: FL, right front wheel: FR, left rear wheel: RL, right rear wheel: RR) of the vehicle 2. Tubeless tires (hereinafter simply referred to as tires) 4FL, 4FR, 4LR, and 4RR are provided with detection devices 10FL, 10FR, 10RL, and 10RR.

  Each of the detection devices 10FL to 10RR detects an air pressure or the like (air pressure and temperature in the present embodiment) in each of the tires 4FL to 4RR, and the detection result is converted into an ultrahigh frequency (UHF) band RF signal (for example, a frequency of 315 MHz). Signal) is wirelessly transmitted to the monitoring device 40 on the vehicle body side.

  Further, in the vicinity of the tires 4FL to 4RR on the vehicle body side, as a transmission means of the present invention, a long wave (LF) band start signal (for example, a frequency of 120 kHz) to the detection devices 10FL to 10RR in the tires 4FL to 4RR. Transmitters 30FL to 30RR for activating each of the detection devices 10FL to 10RR are arranged by transmitting each of the detection devices 10FL to 10RR, and each of the detection devices 10FL to 10RR transmits from the adjacent transmitters 30FL to 30RR. The vehicle is activated in response to the activated signal, detects a tire condition such as air pressure, and transmits the detection result to the monitoring device 40.

  The transmission power of the activation signal (LF signal) from each transmitter 30FL to 30RR is set so that the activation signal reaches only the detection devices 10FL to 10RR corresponding to each transmitter 30FL to 30RR (FIG. 1). The transmission power of the RF signal of each of the detection devices 10FL to 10RR reaches the receiving antenna 42 on the monitoring device 40 side, and the tire condition is detected on the monitoring device 40 side. It is set to such an extent that the result (detected data) can be restored.

  On the other hand, the monitoring device 40 activates the detection devices 10FL to 10RR by individually transmitting activation signals to the detection devices 10FL to 10RR via the transmitters 30FL to 30RR, and then activates the detection devices 10FL activated. The RF signal transmitted from -10RR is received by the receiving antenna 42 as a receiving means, and the received signal is demodulated to monitor the tire condition (air pressure, temperature, etc.) of each tire 4FL-4FR, and the monitoring By outputting the result to a notification device 60 provided in the vicinity of the driver's seat, the tire condition is notified to the occupant.

  The notification device 60 is composed of a display device for displaying the tire condition and an alarm device such as a buzzer and a speaker for notifying the sound when the tire condition is abnormal. Displayed on the display device, and when the tire condition is abnormal, the display device identifies and displays the tire in which the abnormality has occurred, and generates an alarm sound from the alarm device.

Next, the detection devices 10FL to 10RR, the transmitters 30FL to 30RR, and the monitoring device 40 are each configured as shown in FIG.
Since the detection devices 10FL to 10RR and the transmitters 30FL to 30RR provided for each wheel have the same configuration, FIG. 2 shows one detection device 10 and one transmitter 30. In the following description, the detection devices 10FL to 10RR for each wheel are collectively referred to as the detection device 10, and the transmitters 30FL to 30RR for each wheel are collectively referred to as the transmitter 30.

  As shown in FIG. 2, the detection device 10 includes a receiving antenna 12 that receives the activation signal (LF signal) transmitted from the transmitter 30, and a storage device (not shown) that rectifies the received signal from the receiving antenna 12. A power supply circuit 14 that charges a capacitor, generates a DC constant voltage using the power charged in the capacitor, and supplies the DC constant voltage to an internal circuit of the detection device 10, and detects a reception signal from the reception antenna 12 and is included in the reception signal A receiving circuit 16 that restores information, a pressure sensor 22 that detects the air pressure in the tire 4, a temperature sensor 24 that detects the temperature in the tire 4, and the air pressure and temperature detected by these sensors 22 and 24. Based on the information restored by the transmission circuit 28 and the reception circuit 16 that transmit data from the transmission antenna 26 as a detection signal (RF signal) indicating the tire condition, the monitoring device 40, it is determined whether or not a tire condition detection command has been transmitted to the detection device 10, and if it is determined that a detection command has been transmitted, the tire condition (via the pressure sensor 22 and the temperature sensor 24) ( And a control circuit 20 for detecting the detection result (detection data) from the transmission circuit 28.

  Here, the control circuit 20 is configured by a microcomputer centering on a CPU, ROM, RAM, and the like, and a sensor ID, which is identification information unique to the tire in which the detection device 10 is incorporated, is stored in advance in the ROM. It is remembered. Then, when the control circuit 20 is activated upon receiving the direct current constant voltage generated by the power supply circuit 14, it is then determined whether or not the information restored by the receiving circuit 16 is a detection command for the detection device 10. Judgment is made based on the sensor ID included in the information.

  Further, since the transmission circuit 28 used for transmitting the tire state detection data transmits the detection data as a UHF band RF signal, a local oscillator for generating a UHF band carrier wave, and the local oscillator And a modulation circuit that modulates the carrier wave generated according to the output data (detection result) from the control circuit 20, and transmits the RF signal obtained by modulating the carrier wave by the modulation circuit from the transmission antenna 26.

  Similarly to the reception antenna 42 on the monitoring device 40 side, the transmission antenna 26 is configured by an antenna capable of transmitting and receiving a signal in the UHF band (for example, 315 MHz), and the reception antenna 12 is transmitted from the transmitter 30. In order to receive the activation signal (LF signal), the antenna is configured by a resonant antenna that receives the LF signal by utilizing the resonance between the capacitor and the coil.

  Note that the internal circuits of the detection device 10 such as the reception circuit 16, the control circuit 20, and the transmission circuit 28 are all operated by receiving a DC constant voltage generated by the power supply circuit 14. A battery for supplying power to the detection device 10 is not provided in the tire 4 provided with. On the other hand, since the transmitter 30 and the monitoring device 40 are so-called in-vehicle devices, the transmitter 30 and the monitoring device 40 operate by receiving power supply from the in-vehicle battery mounted on the vehicle.

  Next, the transmitter 30 drives the transmission antenna 32 in accordance with the transmission antenna 32 configured using a capacitor and a coil, similarly to the reception antenna 12 in the detection device 10, and the transmission data output from the monitoring device 40. The drive circuit 34 is configured to resonate (in other words, resonate).

  In addition, the monitoring device 40 includes a plurality (four for front, rear, left and right wheels in this embodiment) for outputting transmission data to the transmitter 30 for each wheel (specifically, 30FL to 30RR). The interface circuit (hereinafter referred to as I / F circuit) 46 and the transmission data are sequentially output to each transmitter 30 via each I / F circuit 46, so that the corresponding detection device 10 is transmitted from each transmitter 30. A control circuit 50 that transmits a start signal to the receiver, and a receiving circuit 44 that receives the RF signal transmitted from the detection device 10 via the reception antenna 42 and restores the tire state detection data transmitted by the detection device 10. Is provided.

  The control circuit 50 is configured by a microcomputer centering on a CPU, ROM, RAM, and the like, similar to the control circuit 20 in the detection apparatus 10, and a sensor ID assigned to each detection apparatus 10 is stored in the ROM. And tire position data representing the position of the tire corresponding to the sensor ID is stored in advance.

  When the control circuit 50 transmits an activation signal to each detection device 10, the control circuit 50 reads the sensor ID and the tire position of the tire 4 that is the detection target at that time from the ROM, and is arranged at the read tire position. The transmitter 30 transmits a non-modulated LF signal for a certain period of time, and then transmits a detection command to which the read sensor ID is assigned. An activation signal is transmitted to the detection device 10.

  The transmitter 30 transmits an unmodulated LF signal for a certain period of time to detect the tire condition and transmit the detection result on the detection device 10 side to the power supply circuit 14 on the detection device 10 side. This is to supply necessary power.

  In addition, after transmitting the activation signal, the control circuit 50 receives the return signal (RF signal) from the detection device 10 by the reception antenna 42, and when the detection data is restored by the reception circuit 44, the control circuit 50 The restored detection data is taken in and output to the notification device 60 to notify the occupant of the tire condition.

  Next, the tire state monitoring process executed by the control circuit 50 in the monitoring device 40 in this way to monitor the state of each tire mounted on the vehicle, and the control in the detection device 10 in conjunction with this processing The reply signal transmission process executed by the circuit 20 will be described in detail along the flowchart shown in FIG.

  The tire condition monitoring process shown in FIG. 3 is performed when the vehicle is operated before traveling, such as when the door lock is released by the keyless entry system of the vehicle, or when the ignition switch is turned on. This process is periodically executed at predetermined monitoring time intervals after the engine is started, and the return signal transmission process is executed by the detection device 10 that has received the start signal by executing the tire condition monitoring process. It is processing.

  As shown in FIG. 3, when the monitoring device 40 starts the tire condition monitoring process, first, in step 110 (hereinafter, “step” will be referred to as “S”), transmission arranged near the tire 4 currently being monitored. A start signal is transmitted from a machine (hereinafter referred to as a monitoring target transmitter) 30.

  As described above, the activation signal is transmitted by a procedure of first transmitting an unmodulated LF signal for a certain period of time and then transmitting an LF signal modulated in accordance with a detection command including a sensor ID. Is done.

  Further, immediately after the start of the tire condition monitoring process, the transmitter 30FL at the left front wheel position is set as an initial value of the monitoring target transmitter 30, and then the monitoring target transmitter 30 performs a change process (S150) described later. Is changed to transmitters 30FR, 30RL, and 30RR.

  Next, when the activation signal is transmitted from the monitoring target transmitter 30 in S110, the power supply circuit 14 is connected to the monitoring target transmitter 30 in the detection device 10 in the tire 4 located in the vicinity of the monitoring target transmitter 30. The control circuit 20 is activated in response to the generated power supply voltage and starts a reply signal transmission process.

  In this reply signal transmission process, first, in S310, the reception circuit 16 restores the detection command by determining whether or not the detection command is restored from the activation signal. When the detection command is restored in the receiving circuit 16 (S310: YES), the process proceeds to S320, where it is determined whether or not the sensor ID of the detection device 10 is given to the detection command.

  Also, in S320, if it is determined that the sensor ID of the detection device 10 is not given to the detection command, the reply signal transmission process is terminated, and conversely, the sensor ID of the detection device 10 is set to the detection command. If it is determined that the pressure is applied, the air pressure and temperature in the tire 4 are detected using the pressure sensor 22 and the temperature sensor 24 in S330, and a transmission header is added to the detected data in S340. Then, by outputting to the transmission circuit 28, the detection data is transmitted from the transmission circuit 28, and then the reply signal transmission process is terminated.

  For this reason, in the tire condition monitoring process executed on the monitoring device 40 side, after the activation signal is transmitted from the monitoring target transmitter 30 in S110, the process proceeds to S120, and the receiving circuit 44 for a predetermined time. Determines whether or not a reply signal from the detection apparatus 10 has been received, and waits for the reception circuit 44 to receive a reply signal from the detection apparatus 10 in the vicinity of the monitored transmitter 30.

  If it is determined in S120 that the receiving circuit 44 has received the reply signal from the detection device 10, the process proceeds to S130, and the receiving circuit 44 receives the demodulated received data (the tire condition). Detection data), the abnormality of the tire 4 (air pressure drop, temperature rise, etc.) is determined on the basis of the received data, and the determination result is output to the notification device 60, so that the tire state is indicated to the notification device 60. Let me know.

  Conversely, if it is determined in S120 that the return signal from the detection apparatus 10 is not received by the receiving circuit 44 even though a predetermined time has elapsed after the activation signal is transmitted, the process directly proceeds to S140. Transition. Note that the predetermined time for performing the reception determination of the return signal in S120 is set to be slightly longer than the time required for the detection apparatus 10 to transmit the detection data after receiving the activation signal.

  Next, in S140, it is determined whether or not transmission of activation signals from all transmitters 30 mounted on the vehicle has been completed after activation of the tire condition monitoring process. If it is determined in S140 that the transmission of the activation signal from all the transmitters 30 has been completed, in S150, the monitored transmitter 30 that transmits the activation signal in S110 causes the activation signal to be transmitted. After changing to the transmitter 30 that has not been changed, the process proceeds to S110 again, and the processes after S110 are executed.

  If it is determined in S140 that the transmission of the activation signal from all transmitters 30 has been completed, the process proceeds to S160, and the activation signal is transmitted in S110, but in S120. It is determined whether or not there is a detection device that has not received a reply signal (that is, whether or not a reply error has occurred).

  And in S160, if it is judged that the reply signal has been received from all the detection devices 10 mounted on the vehicle and no reply error has occurred, the tire condition monitoring process is terminated, conversely, If it is determined that there is a reply error, the process proceeds to S200, and a tire condition monitoring process is executed for the tire 4 in which the reply error has occurred.

  The process of S200 is a process of executing again the same processes as S110 to S130 for the monitoring target transmitter 30 when the reply signal cannot be received in S120. When the process of S200 is completed, In S210, it is determined whether or not there is a reply error again at the time of executing the process of S200.

  If it is determined in S210 that there is no reply error during the execution of the process of S200, the tire condition monitoring process is terminated, and conversely, there is a reply error again during the execution of the process of S200. If it is determined that, the following S220 determines whether or not the number of executions (monitoring times) of the monitoring process in S200 for the tire 4 in which a reply error has occurred has reached a preset upper limit value.

  When it is determined in S220 that the number of times of monitoring for the tire 4 having a reply error has not reached the upper limit value, the process proceeds to S200 again, and the tire in which a reply error is determined in S210. 4 is executed again. Conversely, when it is determined in S220 that the number of times of monitoring for the tire 4 in which a reply error has occurred has reached the upper limit value, the tire condition monitoring process is terminated.

  As described above, in the monitoring system of the present embodiment, the transmitters 30FL to 30RR are provided corresponding to the detection devices 10FL to 10RR in the tires 4FL to 4RR. Then, as shown in FIG. 4, when monitoring the state of each of the tires 4FL to 4RR, the monitoring device 40 transmits an activation signal from the transmitters 30FL to 30RR in order, so that each of the detection devices 10FL to 10RR is transmitted. Power is sequentially supplied, and reply signals (RF signals) sequentially transmitted from the detection devices 10FL to 10RR activated by the power supply are received via one reception antenna 42 common to the detection devices 10FL to 10RR. Thus, detection data representing the state of each tire 4FL to 4RR is acquired from each of the detection devices 10FL to 10RR.

  Accordingly, the monitoring device 40 can operate the detection devices 10FL to 10RR only when it is necessary to acquire detection data from the detection devices 10FL to 10RR for monitoring the tire condition. The operation of 10FL to 10RR can be suppressed to the minimum necessary, and the power consumption in each of the detection devices 10FL to 10RR can be reduced.

  In particular, in the present embodiment, the monitoring device 40 supplies power to each of the detection devices 10FL to 10RR by an activation signal transmitted from each of the transmitters 30FL to 30RR to each of the detection devices 10FL to 10RR, so that the inside of each tire 4FL to 4RR. Since the battery for operating each of the detection devices 10FL to 10RR is not built in, the cost of the tire condition monitoring system can be reduced, and the tire condition cannot be monitored due to the battery running out. Therefore, the reliability of the system can be improved.

  Each of the detection devices 10FL to 10RR determines whether the detection command is for itself or another device based on the sensor ID given to the detection command transmitted from the monitoring device 40 side. However, since the detection data is transmitted only when the detection command is for itself, the detection data is simultaneously transmitted from the plurality of detection devices 10FL to 10RR, and the monitoring device 40 transmits the detection data. It is possible to prevent the signal (RF signal) from interfering.

  By the way, even if the monitoring device 40 transmits activation signals from the transmitters 30FL to 30RR, the detection command cannot be restored on the detection devices 10FL to 10RR side due to the surrounding high frequency noise, or the detection device 40 detects the detection command. When the detection data transmitted from the devices 10FL to 10RR cannot be restored, the tire state cannot be monitored on the monitoring device 40 side.

  However, in this embodiment, there is a detection device that could not acquire detection data even though the detection signals were transmitted from the detection devices 10FL to 10RR to all the detection devices 10FL to 10RR in order. When doing so (see the return error shown in FIG. 4), the monitoring device 40 is configured to repeatedly transmit a start signal up to a predetermined number of monitoring times until detection data can be acquired from the detection device.

  For this reason, when the monitoring device 40 monitors the tire condition, even if there is a detection device that cannot acquire detection data due to high-frequency noise interference, the detection data is acquired from the detection device by transmitting the activation signal again. Thus, it becomes possible to prevent a delay in detecting a tire in which an abnormality such as puncture has occurred.

As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, A various aspect can be taken in the range which does not deviate from the summary of this invention.
For example, in the above embodiment, as shown in FIG. 4, the monitoring device 40 sequentially transmits activation signals to all the detection devices 10FL to 10RR mounted on the vehicle, and then returns a response signal corresponding to the activation signal. In other words, detection data can be acquired from the detection device 10 in which a reply error has occurred by configuring the detection device 10 that has not received (that is, detection data) to transmit the activation signal again. As shown in FIG. 5, regarding the retransmission of the activation signal to the detection device 10 in which a reply error has occurred, immediately after determining the reply error in the middle of sequentially transmitting the activation signal to each of the detection devices 10FL to 10RR. You may make it perform.

  In the above-described embodiment, the monitoring device 40 has been described as transmitting the activation signal to each of the detection devices 10FL to 10RR in turn. This is because the detection data is transmitted from the detection devices 10FL to 10RR. For example, as shown in FIG. 6, if the time from receiving the activation signal to transmitting the reply signal (detection data) is set to a different time for each detection device 10, as shown in FIG. The monitoring device 40 may be configured to simultaneously transmit activation signals from the transmitters 30FL to 30RR to the detection devices 10FL to 10RR.

  In this case, re-transmission of the activation signal when a reply error occurs may be executed after the completion of reception of reply signals from all the detection devices 10FL to 10RR.

  Next, in the above-described embodiment, when transmitting detection data from the detection device 10 to the monitoring device 40, an RF signal in the UHF band is used, and when transmitting an activation signal from the monitoring device 40 to the detection device 10. In the above description, the LF signal in the long wave (LF) band that can supply power to the detection device 10 is used. However, the transmission of detection data from the detection device 10 to the monitoring device 40 is the same LF signal as the activation signal. May be used.

  That is, as illustrated in FIG. 7, each detection device 10 includes a drive circuit 29 that transmits detection data from the reception antenna 12 by driving the reception antenna 12 instead of the transmission circuit 28 and the transmission antenna 26 of the above embodiment. In the vicinity of each detection device 10, a transmitter / receiver 31 capable of transmitting / receiving an LF signal via a transmission antenna 32 is provided instead of the transmitter 30, and the monitoring device 40 further includes the reception of the above embodiment. Instead of the antenna 42 and the reception circuit 44, a reception circuit 48 that processes the reception signal from the amplification circuit 36 for amplifying the reception signal provided in the transceiver 31 and restores the detection data is provided for each transceiver 31. By providing, all transmission / reception of data between the detection device 10 and the monitoring device 40 may be performed using the LF signal via the transceiver 31.

  In FIG. 7, the amplifier circuit 36 in the transceiver 31 corresponds to the receiving means of the present invention (Claim 5), and the receiving device 12 and the transmitting antenna 32 in the detector 10 and the transceiver 31 are the present invention. This corresponds to the transmission / reception antenna of claim 6.

  In this way, when the monitoring system is configured using the detection device 10, the transceiver 31, and the monitoring device 40 illustrated in FIG. 7, the monitoring device 40 returns a reply signal (detection data) from each detection device 10. ) Can be acquired individually via the transceiver 31 corresponding to each detection device 10 and the reception circuit 48 corresponding thereto.

  Therefore, in this case, the monitoring device 40 does not set the time from when each of the detection devices 10FL to 10RR receives the activation signal to the time when the reply signal (detection data) is transmitted. When acquiring detection data, as shown in FIG. 8, you may comprise so that a starting signal may be transmitted simultaneously from each detection apparatus 10FL-10RR.

  In the monitoring system shown in FIG. 7, when the monitoring device 40 acquires the detection data from each detection device 10, the procedure shown in FIGS. 4 to 6 is the same as the monitoring system shown in FIGS. The detection data may be acquired by

  Next, in the above embodiment, a sensor ID is registered for each detection device 10, and when the activation signal is transmitted from the monitoring device 40 to each detection device 10, the sensor ID is assigned to the activation signal. Thus, the detection data is transmitted from the specific detection device 10, but the transmission power of the activation signal from the transmitter 30 (or the transmitter / receiver 31) corresponding to each detection device 10 and the directivity of the transmission antenna 32 are described. If the detection device 10 and the transmitter 30 are made to correspond to each tire position on a one-to-one basis by adjusting the characteristics, setting the frequency of the activation signal, etc., without assigning a sensor ID to each detection device 10, Detection data can be acquired from the detection device 10 individually.

It is explanatory drawing showing the structure of the whole monitoring system of an Example. It is a block diagram showing the structure of a detection apparatus, a transmitter, and a monitoring apparatus. It is a flowchart showing the tire condition monitoring process and reply signal transmission process which are each performed by the monitoring apparatus and a detection apparatus. It is a time chart showing the transmission / reception timing of the starting signal and reply signal transmitted / received according to the tire condition monitoring process shown in FIG. FIG. 5 is a time chart showing a modified example of transmission / reception timings of an activation signal and a reply signal shown in FIG. It is a time chart showing the transmission-and-reception timing of a starting signal and a reply signal when a monitoring apparatus transmits a starting signal to each detection apparatus simultaneously. It is a block diagram showing the other structural example of the monitoring system. It is a time chart showing the transmission / reception timing of the starting signal and a reply signal realizable with the monitoring system shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Vehicle, 4, 4FL-4RR ... Tire, 10, 10FL-10RR ... Detection apparatus, 12 ... Reception antenna, 14 ... Power supply circuit, 16 ... Reception circuit, 20 ... Control circuit, 22 ... Pressure sensor, 24 ... Temperature sensor , 26 ... transmitting antenna, 28 ... transmitting circuit, 29 ... driving circuit, 30, 30FL to 30RR ... transmitter, 31 ... transceiver, 32 ... transmitting antenna, 34 ... driving circuit, 36 ... amplifier circuit, 40 ... monitoring device, 42 ... receiving antenna, 44 ... receiving circuit, 48 ... receiving circuit, 50 ... control circuit, 60 ... notification device.

Claims (12)

A plurality of detection devices that are each incorporated in a plurality of tires of a vehicle, detect a tire condition including at least the air pressure of each tire, and transmit the detection results wirelessly;
A monitoring device mounted on a vehicle and monitoring the tire condition of each tire by receiving detection results transmitted from the detection devices, and notifying the occupant of the monitoring results;
A vehicle tire condition monitoring system comprising:
Each of the tires is disposed in the vicinity of each of the tires, and includes a plurality of transmission means for wirelessly transmitting an activation signal to the detection device in each tire,
The monitoring device activates the detection devices by transmitting activation signals from the transmission means, and then receives detection results transmitted from the detection devices. Monitor tire condition,
Each of the detection devices is activated by receiving an activation signal transmitted from each of the transmission means, detects the tire condition and transmits the detection result, and then stops operation. Vehicle tire condition monitoring system. Each transmitting means is configured to transmit a long wave band signal as the activation signal,
Each of the detection devices includes a power supply circuit that generates a power supply voltage by rectifying the start signal transmitted from the transmission means, and starts when the power supply voltage is generated by the power supply circuit to The vehicle tire condition monitoring system according to claim 1, wherein detection and transmission of the detection result are performed.   The monitoring device receives a transmission signal from each detection device via one receiving means common to each detection device, and acquires the detection result of the tire condition by each detection device. The vehicle tire condition monitoring system according to claim 1 or 2.   4. The vehicle tire condition monitoring system according to claim 3, wherein each of the detection devices transmits a detection result of the tire condition with a radio signal of an ultra-short wave or an ultra-short wave. In the vicinity of each tire, a transmitter / receiver provided with the transmitting means and a receiving means for receiving a radio signal transmitted from a detecting device in the adjacent tire is provided,
The monitoring device acquires the detection result of the tire condition transmitted from each of the detection devices via a reception unit in a transceiver arranged in the vicinity of the tire in which the detection device is incorporated. The vehicle tire condition monitoring system according to claim 1. Each of the detection devices and the transceivers each include a transmission / reception antenna for transmitting / receiving a signal in a long wave band,
In the transceiver, the transmission means transmits a long-wave band signal as the activation signal via the transmission / reception antenna, and the reception means transmits a transmission signal from a detection device in an adjacent tire via the transmission / reception antenna. And receiving the output signal to the monitoring device,
Each detection device includes a power supply circuit that generates a power supply voltage by rectifying a start signal from the transmission means received by the transmission / reception antenna, and starts when the power supply voltage is generated by the power supply circuit The vehicle tire condition monitoring system according to claim 5, wherein the tire condition is detected, and the detection result is wirelessly transmitted via the transmission / reception antenna.   The monitoring device individually activates the detection devices by causing the transmission means to transmit the activation signals at different timings, and after transmitting the activation signal, the tire condition transmitted from the corresponding detection device. The vehicle tire condition monitoring system according to any one of claims 1 to 6, wherein the tire condition of each tire is individually monitored by individually acquiring detection results.   When the monitoring device cannot acquire the tire condition detection result transmitted from the corresponding detection device after transmitting the activation signal, the monitoring device causes the transmission signal corresponding to the detection device to transmit the activation signal again. The vehicle tire condition monitoring system according to claim 7, wherein a tire condition detection result from the detection device is acquired.   The monitoring device sequentially transmits a start signal to each of the transmission units, and then transmits a start signal again from the transmission unit corresponding to the detection device that could not acquire the tire condition detection result by transmitting the start signal. The vehicle tire condition monitoring system according to claim 8. Each of the detection devices is configured to transmit the detection result of the tire state after a lapse of different elapsed time after receiving the activation signal,
The monitoring device simultaneously activates the detection devices by simultaneously transmitting activation signals from the transmission units, and then sequentially acquires tire condition detection results transmitted at different timings from the detection devices. The tire condition monitoring system for a vehicle according to any one of claims 1 to 6, wherein the tire condition of each tire is monitored.   The monitoring device simultaneously activates the detection devices by simultaneously transmitting activation signals from the transmission units, and transmits the activation signals from the detection devices via the reception units after transmission of the activation signals. 7. The vehicle tire condition monitoring system according to claim 5 or 6, wherein the tire condition of each tire is monitored by individually acquiring the detection results of the detected tire condition.   When there is a detection device that cannot acquire a tire condition detection result after transmitting the activation signal, the monitoring device transmits the activation signal again from a transmission unit corresponding to the detection device, thereby detecting the detection device. The vehicle tire condition monitoring system according to claim 10 or 11, wherein a tire condition detection result is acquired from the vehicle.

Images