JP2022090558A - Tire condition monitoring system, receiver, and transmitter - Google Patents

Abstract

To provide a tire condition monitoring system, a receiver, and a transmitter in which they are easily installed to a vehicle, and consumption power can be decreased.SOLUTION: A tire condition monitoring system 1 comprises: a transmitter 2 which is arranged in a vehicular tire, acquires information indicating tire condition, and repeatedly transmits a signal including the information indicating tire condition; and a receiver 3 which is arranged in a vehicle body of the vehicle, and receives the signal. The receiver can be switchable between a first reception mode where a signal is always received and a second reception mode where a cycle consisting of a signal receiving condition and a signal unreceiving condition following it is repeated. When no signal is continuingly received for a specific period while the receiver is activated at the first reception mode, it is switched to the second reception mode.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire condition monitoring system, a receiver, and a transmitter.

Conventionally, there has been known a tire condition monitoring system that monitors the condition of a tire by transmitting information from a sensor installed on the tire from a transmitter installed on the tire to a receiver installed on the vehicle body of the vehicle. In the system, there is known a technique of changing the operating state of a transmitter or a receiver according to the operating state of a vehicle in order to reduce power consumption. For example, Patent Document 1 discloses a tire pressure monitoring device that changes the operating state of a transmitter or a receiver based on information acquired by a wheel speed sensor installed on a vehicle body.

Japanese Unexamined Patent Publication No. 2005-153641

However, in the conventional technique, in order for the receiver to receive information about the operating state of the vehicle from other in-vehicle devices such as wheel speed sensors, it is necessary to wire and connect the receiver to other in-vehicle devices or accessory power supplies. , It took a lot of man-hours to install the receiver on the car body.

An object of the present invention made in view of such circumstances is to provide a tire condition monitoring system, a receiver, and a transmitter capable of reducing power consumption while facilitating installation in a vehicle.

The tire condition monitoring system according to the present invention is installed on the tire of the vehicle, acquires information indicating the condition of the tire, and repeatedly transmits a signal including the information indicating the condition of the tire, and the vehicle body of the vehicle. A first reception mode in which the receiver is always capable of receiving the signal, and a state in which the signal can be received and a state in which the signal is not received thereafter. The operation can be switched between the second reception mode in which the cycle consisting of the above is repeated, and the second reception is performed when the signal is not continuously received for a predetermined period during the operation in the first reception mode. It is configured to switch the operation to the mode.
According to such a configuration, the receiver can switch the operation mode based on the signal received from the transmitter without receiving the information from the device other than the transmitter. Therefore, it is possible to reduce the power consumption while facilitating the installation of the tire condition monitoring system in the vehicle.

In the tire condition monitoring system according to the present invention, the transmitter repeatedly transmits the signal at a first transmission mode in which the signal is repeatedly transmitted at a first time interval and a second time interval longer than the first time interval. The operation can be switched in the second transmission mode, and when it is determined that the vehicle is stopped during the operation in the first transmission mode, the operation is switched to the second transmission mode. It is preferably configured. According to such a configuration, the power consumption of the transmitter can be reduced.

In the tire condition monitoring system according to the present invention, the transmitter acquires information indicating the running state of the vehicle, and when the speed of the vehicle is continuously equal to or lower than a predetermined speed for the first period, the vehicle It is preferable to determine that the vehicle is stopped. According to such a configuration, the transmitter can determine that the vehicle 4 is stopped with a simple configuration.

In the tire condition monitoring system according to the present invention, it is preferable that the data length of the signal transmitted in the second transmission mode is longer than the data length of the signal transmitted in the first transmission mode. According to such a configuration, the receiver can accurately receive the signal without failing to receive the signal even during the operation in which the power consumption is suppressed.

In the tire condition monitoring system according to the present invention, the transmitter switches the operation to the first transmission mode when it is determined that the vehicle is not stopped during the operation in the second transmission mode, and the operation is switched to the first transmission mode. The data length of the signal transmitted from the transmitter is the data of the signal transmitted in the second transmission mode a predetermined number of times after the operation of the transmitter is switched from the second transmission mode to the first transmission mode. It is preferably left long. According to such a configuration, the receiver can accurately receive the signal without failing to receive it even when the operation mode is switched.

In the tire condition monitoring system according to the present invention, the signal includes information indicating an operating state of the transmitter, and the receiver is included in the signal received during operation in the second receiving mode. When it is determined that the transmitter is in the first transmission mode based on the information indicating the operating state of the transmitter, it is preferable to switch the operation to the first reception mode. According to such a configuration, the receiver can change the operation mode of the receiver when it is determined that the frequency of receiving the signal by the receiver increases.

In the tire condition monitoring system according to the present invention, the duration of one cycle of the receiver in the second reception mode is the duration of the signal transmitted by the transmitter during operation in the second transmission mode. Is also preferred to be short. According to such a configuration, the receiver can accurately receive the signal transmitted by the transmitter in the second transmission mode without failing to receive the signal while operating in the second reception mode.

In the tire condition monitoring system according to the present invention, the duration of the signal is preferably 1.5 to 2 times the duration of the one cycle. According to such a configuration, the receiver can accurately receive the signal.

The receiver according to the present invention is a receiver included in the above-mentioned tire condition monitoring system, which is a state in which the signal can always be received, a first reception mode, a state in which the signal can be received, and subsequent states. The operation can be switched between the second reception mode in which the cycle consisting of the non-reception state is repeated, and the signal is not received continuously for a predetermined period during the operation in the first reception mode. It is configured to switch the operation to the second reception mode.
According to such a configuration, the receiver can switch the operation mode based on the signal received from the transmitter without receiving the information from the device other than the transmitter. Therefore, in the tire condition monitoring system, it is possible to reduce the power consumption while facilitating the installation of the receiver in the vehicle.

The transmitter according to the present invention is a transmitter included in the tire condition monitoring system described above, and has a first transmission mode in which the signal is repeatedly transmitted at a first time interval and a second transmission mode longer than the first time interval. The operation can be switched between the second transmission mode in which the signal is repeatedly transmitted at time intervals, and the first is the case where it is determined that the vehicle is stopped during the operation in the first transmission mode. 2 It is configured to switch the operation to the transmission mode.
According to such a configuration, in the tire condition monitoring system, the receiver can be configured to be able to switch the operation mode based on the signal received from the transmitter without receiving information from a device other than the transmitter. .. Therefore, it becomes easy to install the receiver in the vehicle in the tire condition monitoring system. Further, in the tire condition monitoring system, the power consumption of the transmitter can be reduced.

According to the present invention, it is possible to provide a tire condition monitoring system, a receiver, and a transmitter that can reduce power consumption while facilitating installation in a vehicle.

It is a schematic diagram which shows schematic the tire condition monitoring system which concerns on one Embodiment of this invention. FIG. 3 is a functional block diagram schematically showing a transmitter configuration included in FIG. 1. It is a flowchart which shows the operation of a transmitter. FIG. 3 is a functional block diagram schematically showing a configuration of a receiver included in FIG. 1. It is a flowchart which shows the operation of a receiver. It is a schematic diagram which shows schematic the operation state of the receiver in the 2nd reception mode. It is the schematic which shows the operation of the tire condition monitoring system which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals. In the description of the present embodiment, the description will be omitted or simplified as appropriate for the same or corresponding parts.

(Configuration of tire condition monitoring system)
An outline of the tire condition monitoring system 1 according to the present embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic view schematically showing a tire condition monitoring system 1 according to an embodiment of the present invention. The tire condition monitoring system 1 includes a transmitter 2 and a receiver 3.

The tire condition monitoring system 1 is used to monitor the condition of the tire 5 of the vehicle 4. The state of the tire 5 is, for example,, but is not limited to, the internal pressure, temperature, strain, and the like of the tire.

The vehicle 4 is, for example, an automobile such as a passenger car, a truck, a bus, and a two-wheeled vehicle. However, the vehicle 4 is not limited to an automobile, and may be any vehicle 4 having a tire 5.

The tire 5 is, for example, a pneumatic tire. In such a case, the tire 5 is attached to the rim of the wheel and is filled with air up to the specified internal pressure. However, the tire 5 is not limited to air, and may be filled with a gas such as nitrogen, or any fluid containing a liquid or a gel-like substance up to a specified internal pressure.

The transmitter 2 is installed on the tire 5 of the vehicle 4. For example, the transmitter 2 may be installed so as to face the internal space of the tire 5 by being integrally configured with the air valve of the tire 5. The transmitter 2 acquires information indicating the state of the tire 5, and wirelessly transmits a signal including the acquired information indicating the state of the tire 5. The receiver 3 is installed on the vehicle body 4A of the vehicle 4 and receives the signal transmitted from the transmitter 2. The positions and numbers of the transmitter 2, the receiver 3, and the tire 5 in the vehicle 4 shown in FIG. 1 are examples, and can be arbitrarily determined according to their uses and the like. For example, a plurality of transmitters 2 may be included in the tire condition monitoring system 1 depending on the number of tires 5 included in the vehicle 4.

The tire condition monitoring system 1 may further include an in-vehicle device 6 and a battery 7 of the vehicle 4. The in-vehicle device 6 may be any computer installed in the vehicle 4, such as a control device (ECU: Electronic Control Unit) of the vehicle 4, a car navigation system, or the like. The in-vehicle device 6 may be installed integrally with the vehicle 4 or may be detachably installed.

The receiver 3 and the vehicle-mounted device 6 are connected to each other so as to be able to communicate with each other by wire or wirelessly via a vehicle-mounted network such as a CAN (Controller Area Network) or a dedicated line. For example, the receiver 3 transmits information indicating the state of the tire 5 received from the transmitter 2 to the in-vehicle device 6. As a result, the in-vehicle device 6 can display information indicating the state of the tire 5 so that the driver of the vehicle 4 can view it. Alternatively, the vehicle-mounted device 6 can control the vehicle 4 based on the information indicating the state of the tire 5. Further, the receiver 3 may be directly connected to the battery 7. As a result, it is not necessary to wire the receiver 3 to the accessory power supply in order to receive the power supply, and the receiver 3 can be easily installed in the vehicle 4. In particular, in a large vehicle such as a truck, wiring to an accessory power supply requires advanced knowledge and skills such as raising the cabin, which is effective.

Next, the transmitter 2 and the receiver 3 of the tire condition monitoring system 1 will be described in detail.

(Transmitter configuration)
The configuration of the transmitter 2 according to the present embodiment will be described with reference to FIG. FIG. 2 is a functional block diagram schematically showing the configuration of the transmitter 2. As shown in FIG. 2, the transmitter 2 includes a first sensor unit 21, a second sensor unit 22, a communication unit 23, a storage unit 24, and a control unit 25. The first sensor unit 21, the second sensor unit 22, the communication unit 23, the storage unit 24, and the control unit 25 are connected to each other so as to be able to communicate with each other by wire or wirelessly.

The first sensor unit 21 includes one or more sensors. The sensor of the first sensor unit 21 is, for example, a pressure sensor, a temperature sensor, a strain sensor, or the like. As a result, the first sensor unit 21 acquires information indicating the state of the tire 5, such as the internal pressure, temperature, or strain of the tire 5. The sensor included in the first sensor unit 21 is not limited to the above-mentioned sensor, and may be arbitrarily determined according to the information to be acquired as the information indicating the state of the tire 5.

The second sensor unit 22 includes one or more sensors. The sensor of the second sensor unit 22 is, for example, an acceleration sensor, an angular velocity sensor, or the like. As a result, the second sensor unit 22 acquires information indicating the traveling state of the vehicle 4, such as acceleration and angular velocity. Although the details will be described later, the information acquired by the second sensor unit 22 is used to change the operation mode of the transmitter 2 according to the traveling state of the vehicle 4. The sensor included in the second sensor unit 22 is not limited to the above-mentioned sensor, and may be arbitrarily determined according to the information to be acquired as the information indicating the traveling state of the vehicle 4.

The communication unit 23 includes one or more wireless communication modules. The communication module is, for example, a communication module corresponding to a communication standard such as a wireless LAN (local area network) or Bluetooth (registered trademark). As a result, the communication unit 23 wirelessly transmits a signal including information indicating the state of the tire 5 to the receiver 3.

The storage unit 24 is, for example, a semiconductor memory, a magnetic memory, an optical memory, or the like. The storage unit 24 may function as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 24 stores arbitrary information used for the operation of the transmitter 2. For example, the storage unit 24 may store a system program, an application program, embedded software, or the like. Further, the storage unit 24 may store information necessary for operating the transmitter 2 in a plurality of operation modes.

The control unit 25 includes one or more processors. The processor may be, for example, a general-purpose processor such as a CPU (Central Processing Unit), a dedicated processor specialized for a specific process, or the like. The control unit 25 is not limited to the processor, and may include one or more dedicated circuits. The dedicated circuit may be, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

Each of the control units 25 is to realize the functions of the transmitter 2 including the functions of the components such as the first sensor unit 21, the second sensor unit 22, the communication unit 23, and the storage unit 24 described above. Control the components. Further, as a function of the transmitter 2, the control unit 25 is provided with a time measuring function such as a timer in order to measure the time when the processing is executed or to execute the processing at a predetermined time interval.

With reference to FIG. 3, the operation of the transmitter 2 realized by controlling each function of the transmitter 2 by the control unit 25 will be described. FIG. 3 is a flowchart showing the operation of the transmitter 2. This operation corresponds to the control method of the transmitter 2.

In step S101, the control unit 25 acquires information indicating the state of the tire 5.

Specifically, the control unit 25 acquires information indicating the state of the tire 5 by the first sensor unit 21. The information indicating the state of the tire 5 is, for example, the internal pressure of the tire 5 acquired by the pressure sensor. The control unit 25 may store the acquired information indicating the state of the tire 5 in the storage unit 24 in association with the acquisition time of the information.

In step S102, the control unit 25 acquires information indicating the traveling state of the vehicle 4.

Specifically, the control unit 25 acquires information indicating the traveling state of the vehicle 4 by the second sensor unit 22. The information indicating the traveling state of the vehicle 4 is, for example, the angular velocity of the tire 5 acquired by the angular velocity sensor. The control unit 25 may store the acquired information indicating the running state of the vehicle 4 in the storage unit 24 in association with the acquisition time of the information.

In step S103, the control unit 25 determines whether or not the vehicle 4 is stopped. For example, the control unit 25 may determine that the vehicle 4 is stopped when the speed of the vehicle 4 is continuously equal to or lower than the predetermined speed S for the first period. The first period is, for example, 15 minutes. The predetermined speed S is, for example, 5 km / h. However, the first period and the predetermined speed S may be arbitrarily determined.

More specifically, the control unit 25 calculates the speed of the vehicle 4 based on the information indicating the traveling state of the vehicle 4 acquired by the second sensor unit 22. The control unit 25 determines whether or not the calculated speed of the vehicle 4 is continuously equal to or lower than the predetermined speed S for the first period. For example, when the information indicating the traveling state of the vehicle 4 is the angular velocity of the tire 5, the control unit 25 calculates the speed of the vehicle 4 from the angular velocity of the tire 5. However, even if the control unit 25 determines whether or not the information indicating the running state of the vehicle 4 acquired by the second sensor unit 22 exceeds a predetermined threshold value without actually calculating the speed of the vehicle 4. good. For example, when the information indicating the traveling state of the vehicle 4 is the angular velocity of the tire 5, the control unit 25 keeps the angular velocity of the tire 5 for the first period and does not exceed the predetermined angular velocity corresponding to the predetermined speed S. In this case, it may be determined that the vehicle 4 is stopped.

On the other hand, when the calculated speed of the vehicle 4 exceeds a predetermined speed S, the control unit 25 may immediately determine that the vehicle 4 is running, that is, it is not stopped.

In step S103, when it is determined that the vehicle 4 is traveling, that is, the vehicle 4 is not stopped (step S103-NO), in step S104, the control unit 25 provides information indicating the state of the tire 5. The transmitter 2 is operated in the first transmission mode (normal transmission mode) in which the included signal is repeatedly transmitted at the first time interval. The first transmission mode is a mode in which a signal including information indicating the state of the tire 5 is repeatedly transmitted in a situation where the state of the tire may change, such as while the vehicle 4 is running. The first time interval is, for example, every 1 to 10 minutes. However, the first time interval may be any time interval other than 1 to 10 minutes.

Specifically, the control unit 25 determines whether or not the first time has elapsed since the last signal was transmitted. When the control unit 25 determines that the first time has elapsed since the last signal was transmitted, the control unit 25 generates a signal including information indicating the state of the tire 5 acquired by the first sensor unit 21. In addition to the information indicating the state of the tire 5, the signal includes the preamble, information indicating the operation mode of the transmitter 2 (for example, in this step, a flag set with a value indicating the "first transmission mode"), and the transmitter. It may include an identifier uniquely indicating 2 (for example, a transmitter ID). The preamble is data such as a bit string, which defines a start position of a data body transmitted by a signal and is set in front of the data body in order to synchronize communication. In the first transmission mode, the preamble data length is, for example, 2 to 5 ms when transmitting at a data rate of 10 kbps.

The control unit 25 controls the communication unit 23 to transmit the generated signal. When the signal is transmitted, the control unit 25 stores the time when the signal is transmitted as the time when the signal was last transmitted in the storage unit 24, and repeats the process from step S101. The control unit 25 may store the operation mode of the transmitter 2 at the time of transmission, the content of the transmitted signal, and the like in the storage unit 24 in association with the time when the signal was last transmitted.

On the other hand, when the control unit 25 determines that the first time has not elapsed since the last signal was transmitted, the control unit 25 repeats the process from step S101 without generating and transmitting the signal.

In step S103, when it is determined that the vehicle 4 is stopped, that is, the vehicle 4 is not traveling (step S103-YES), in step S105, the control unit 25 provides information indicating the state of the tire 5. The transmitter 2 is operated in the second transmission mode (power saving mode) in which the included signals are repeatedly transmitted at the second time interval longer than the first time interval. The second transmission mode is a mode in which a signal including information indicating the state of the tire 5 is transmitted at a longer interval than the first transmission mode in a situation where the state of the tire is unlikely to change, such as when the vehicle 4 is stopped. The second time interval is, for example, every hour. However, the second time interval may be any time interval other than one hour, which is longer than the first time interval.

Specifically, the control unit 25 determines whether or not the second time has elapsed since the last signal was transmitted. When the control unit 25 determines that the second time has elapsed since the last signal was transmitted, the control unit 25 generates a signal including information indicating the state of the tire 5 acquired by the first sensor unit 21. In addition to the information indicating the state of the tire 5, the signal includes the preamble, information indicating the operation mode of the transmitter 2 (for example, in this step, a flag set with a value indicating the "second transmission mode"), and the transmitter. It may include an identifier uniquely indicating 2.

The data length of the signal transmitted in the second transmission mode is longer than the data length of the signal transmitted in the first transmission mode. That is, the duration of the signal transmitted in the second transmission mode is longer than the duration of the signal transmitted in the first transmission mode. For example, the data length of the signal may be lengthened by making the preamble included in the signal in the second transmission mode a long preamble and making it longer than the preamble included in the signal in the first transmission mode. As a result, the transmitter 2 can make the receiver 3 accurately receive the signal without failing to receive the signal even during the operation in which the receiver 3 suppresses the power consumption. For example, the data length of the signal in the second transmission mode may be set to a length in the range of 1 to 1.4 times the data length of the signal in the first transmission mode. Therefore, the signal preamble in the second transmission mode has a longer data length of, for example, about 200 ms when transmitting at a data rate of 10 kbps than the signal preamble in the first transmission mode.

The data length of the signal transmitted from the transmitter 2 is the data length of the signal transmitted in the second transmission mode a predetermined number of times after the operation of the transmitter 2 is switched from the second transmission mode to the first transmission mode. May be left alone. The predetermined number of times is, for example, two times, but is not limited to this. As a result, even if there is a time lag between the operation of the transmitter 2 switching from the second transmission mode to the first transmission mode and the switching of the receiver 3 from the second reception mode to the first reception mode, the receiver 3 can accurately receive the signal without failing to receive it.

The control unit 25 controls the communication unit 23 to transmit the generated signal. When the signal is transmitted, the control unit 25 stores the time when the signal is transmitted as the time when the signal was last transmitted in the storage unit 24, and repeats the process from step S101. The control unit 25 may store the operation mode of the transmitter 2 at the time of transmission, the content of the transmitted signal, and the like in the storage unit 24 in association with the time when the signal was last transmitted.

On the other hand, when the control unit 25 determines that the second time has not elapsed since the last signal was transmitted, the control unit 25 repeats the process from step S101 without generating and transmitting the signal.

(Receiver configuration)
The configuration of the receiver 3 according to the present embodiment will be described with reference to FIG. FIG. 4 is a functional block diagram schematically showing the configuration of the receiver 3. As shown in FIG. 4, the receiver 3 includes a communication unit 31, a storage unit 32, and a control unit 33. The communication unit 31, the storage unit 32, and the control unit 33 are connected to each other so as to be able to communicate with each other by wire or wirelessly.

The communication unit 31 includes one or more wireless communication modules. The communication module is, for example, a communication module corresponding to a communication standard such as a wireless LAN or Bluetooth. As a result, the communication unit 31 wirelessly receives the signal including the information indicating the state of the tire 5 transmitted from the transmitter 2.

The storage unit 32 is, for example, a semiconductor memory, a magnetic memory, an optical memory, or the like. The storage unit 32 may function as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 32 stores arbitrary information used for the operation of the receiver 3. For example, the storage unit 32 may store a system program, an application program, embedded software, or the like. Further, the storage unit 32 may store information necessary for operating the receiver 3 in a plurality of operation modes.

The control unit 33 includes one or more processors. The processor may be, for example, a general-purpose processor such as a CPU, a dedicated processor specialized for a specific process, or the like. The control unit 33 is not limited to the processor, and may include one or more dedicated circuits. The dedicated circuit may be, for example, FPGA or ASIC.

The control unit 33 controls each component in order to realize the function of the receiver 3, including the functions of the components such as the communication unit 31 and the storage unit 32 described above. Further, as a function of the receiver 3, the control unit 33 is provided with a time measuring function such as a timer in order to measure the time when the processing is executed or to execute the processing at a predetermined time interval.

With reference to FIG. 5, the operation of the receiver 3 realized by controlling each function of the receiver 3 by the control unit 33 will be described. FIG. 5 is a flowchart showing the operation of the receiver 3. This operation corresponds to the control method of the receiver 3.

In step S201, the control unit 33 operates the receiver 3 in the first reception mode (normal reception mode) in which signals can always be received. The first reception mode is a mode in which a signal including information indicating the state of the tire 5 transmitted from the transmitter 2 at a high frequency is repeatedly received from the transmitter 2 in a situation where the state of the tire may change, such as while the vehicle 4 is running. be. The first reception mode of the receiver 3 is an operation mode corresponding to the first transmission mode of the transmitter 2.

Specifically, the control unit 33 controls the communication unit 31 so that the signal can always be received. As a result, the control unit 33 can receive the signal from the communication unit 31 at any time when a signal including information indicating the state of the tire 5 is transmitted from the transmitter 2. When the control unit 33 receives a signal, the control unit 33 stores the received signal in the storage unit 32. The control unit 33 further stores the time when the signal is received in the storage unit 32 as the time when the signal was last received.

In step S202, the control unit 33 determines whether or not the signal has been continuously received for the second period. The second period is, for example, 15 minutes or more. The second period is a time longer than the first time interval, which is the time interval for the transmitter 2 to transmit the signal in the first transmission mode, and is the time interval for the transmitter 2 to transmit the signal in the second transmission mode. The time is shorter than the second time interval. In the present embodiment, the second period is equal to the first period described above, but may be different from the first period.

Specifically, the control unit 33 measures the elapsed time from the time when the signal was last received. When it is determined that the second period has elapsed from the time when the signal was last received, the control unit 33 determines that the signal has not been continuously received for the second period.

In step S202, when it is determined that the second period has not elapsed from the time when the signal was last received (step S202-NO), the control unit 33 operates the receiver 3 in the first reception mode. The process from step S201 is repeated as it is.

When it is determined in step S202 that the second period has elapsed from the time when the signal was last received (step S202-YES), in step S203, the control unit 33 is in a state where the signal can be received and the subsequent reception. The receiver 3 is operated in the second reception mode (intermittent reception mode) in which the cycle consisting of the non-existent state is repeated. The second reception mode is a mode in which a signal including information indicating the state of the tire 5 transmitted from the transmitter 2 at a low frequency is repeatedly received from the transmitter 2 in a situation where the state of the tire is unlikely to change, such as when the vehicle 4 is stopped. be. The second reception mode of the receiver 3 is an operation mode corresponding to the second transmission mode of the transmitter 2. As a result, the control unit 33 switches the operation of the receiver 3 from the first reception mode to the second reception mode without receiving the notification that the transmitter 2 has switched from the first transmission mode to the second transmission mode. Can be done.

The second reception mode of the receiver 3 will be described in more detail with reference to FIG. FIG. 6 is a schematic diagram schematically showing an operating state of the receiver 3 in the second reception mode. In FIG. 6, the control unit 33 operates the receiver 3 so as to repeat a cycle consisting of a state in which signals can be received and a state in which signals cannot be received.

Specifically, as shown in FIG. 6, the control unit 33 controls the communication unit 31 so that the _signal can be received during the duration TON. Next, the control unit 33 controls the communication unit 31 so that the signal is not received during the duration T _OFF . By repeating these processes, the control unit 33 sets the receiver 3 so that the cycle consisting of a state in which the signal can be received and a state in which the signal cannot be received is repeated with a duration T _TOTAL ( _{TON + T OFF =} T _TOTAL ). Make it work. For example, the control unit 33 may activate the communication unit 31 so that the communication unit 31 can receive a signal, and stop the communication unit 31 so that the communication unit 31 does not receive the signal. .. The duration _TON is, for example, 10 ms. The duration T _OFF is, for example, 50 ms to 150 ms. In this way, the control unit 33 can suppress the power consumption of the receiver 3 by providing a period for partially limiting the functions of the receiver 3.

Here, the duration T _TOTAL of one cycle is shorter than the duration of the signal transmitted by the transmitter 2 in the second transmission mode. More preferably, the duration T _TOTAL of one cycle is shorter than the preamble of the signal transmitted by the transmitter 2 in the second transmission mode. As a result, the receiver 3 can accurately receive the signal transmitted by the transmitter 2 in the second transmission mode in the second reception mode without failing to receive the signal. For example, the duration of the signal in the second transmission mode may be 1.5 to 2 times the duration _TTOTAL of one cycle. As a result, the power consumption of the transmitter 2 can be suppressed while causing the receiver 3 to accurately receive the signal.

With reference to FIG. 5 again, in step S204, the control unit 33 determines whether or not the transmitter 2 is operating in the first transmission mode based on the signal received from the transmitter 2.

Specifically, the control unit 33 determines whether or not the transmitter 2 is operating in the first transmission mode based on the information indicating the operation mode of the transmitter 2 included in the signal received from the transmitter 2. judge.

In step S204, when it is determined that the transmitter 2 is operating in the first transmission mode while the receiver 3 is operating in the second reception mode (step S204-YES), the control unit 33 controls the step S201. The process from the above is repeated to switch the receiver 3 from the second reception mode to the first reception mode.

On the other hand, when it is determined in step S204 that the transmitter 2 is not operating in the first transmission mode (step S204-NO), the control unit 33 keeps the receiver 3 operating in the second reception mode. , The process from step S203 is repeated.

(Operation of tire condition monitoring system)
The operation of the tire condition monitoring system 1 in the present embodiment will be described with reference to FIG. 7. FIG. 7 is a schematic diagram schematically showing the operation of the tire condition monitoring system 1. In this operation, the tire condition monitoring system 1 is used to monitor the internal pressure of the air filled in the tire 5 as an example of the information indicating the condition of the tire 5. In such a case, the tire condition monitoring system 1 is also referred to as a tire pressure monitoring system (TPMS).

At time point T0, it is assumed that the vehicle 4 is stopped, the transmitter 2 is operating in the second transmission (power saving) mode, and the receiver 3 is operating in the second reception (intermittent reception) mode. .. Specifically, the transmitter 2 repeatedly transmits a signal including information indicating the state of the tire 5 at the second time interval in the second transmission mode. In the second reception mode, the receiver 3 repeats a state in which the signal can be received and a state in which the signal cannot be received at predetermined time intervals.

At the time point T1, the vehicle 4 is still stopped, and the control unit 25 of the transmitter 2 stops the vehicle 4 based on the information indicating the running state of the vehicle 4 acquired by the second sensor unit 22. It is determined that it is. The control unit 25 of the transmitter 2 keeps the transmitter 2 operating in the second transmission mode, and repeatedly transmits a signal including information indicating the state of the tire 5 at the second time interval. The control unit 33 of the receiver 3 receives a signal from the transmitter 2, and the transmitter 2 operates in the second transmission mode based on the information including the information indicating the operation mode of the transmitter 2 included in the received signal. It is determined that there is. Therefore, the control unit 33 of the receiver 3 keeps the receiver 3 operating in the second reception mode.

After that, when the vehicle 4 starts traveling and the speed of the vehicle 4 exceeds a predetermined speed S at the time point T2, the control unit 25 of the transmitter 2 is acquired by the second sensor unit 22 of the vehicle 4. It is determined that the vehicle 4 is traveling based on the information indicating the traveling state of the vehicle 4. As a result, the control unit 25 of the transmitter 2 switches the operation of the transmitter 2 from the second transmission mode to the first transmission (normal) mode, and sends a signal including information indicating the state of the tire 5 at the first time interval. Send repeatedly. Specifically, the control unit 25 of the transmitter 2 transmits a signal including information indicating the state of the tire 5 when it is determined that the first time has elapsed since the last signal was transmitted. At this time, the control unit 25 of the transmitter 2 keeps the data length of the signal to be transmitted as the data length of the signal transmitted in the second transmission mode for a predetermined number of times (twice in this embodiment). Then, at the time point T3, the control unit 33 of the receiver 3 receives the signal from the transmitter 2, and the transmitter 2 first receives the signal based on the information indicating the operation mode of the transmitter 2 included in the received signal. Judge that it is operating in the transmission mode. As a result, the control unit 33 of the receiver 3 operates the receiver 3 in the first reception mode in which the signal can always be received.

At the time point T4, the vehicle 4 is still running, and the control unit 25 of the transmitter 2 is running the vehicle 4 based on the information indicating the running state of the vehicle 4 acquired by the second sensor unit 22. It is determined that there is. The control unit 25 of the transmitter 2 keeps the transmitter 2 operating in the first transmission mode, and repeatedly transmits a signal including information indicating the state of the tire 5 at the first time interval. The control unit 33 of the receiver 3 receives a signal from the transmitter 2, and the transmitter 2 operates in the first transmission mode based on the information including the information indicating the operation mode of the transmitter 2 included in the received signal. It is determined that there is. The control unit 33 of the receiver 3 keeps the receiver 3 operating in the first reception mode.

After that, the vehicle 4 decelerates, and at the time point T5, the speed of the vehicle 4 falls below the predetermined speed S. Then, at the time point T6, the control unit 25 of the transmitter 2 continuously determines the speed of the vehicle 4 for the first period based on the information indicating the traveling state of the vehicle 4 acquired by the second sensor unit 22. Since the speed is S or less, it is determined that the vehicle 4 is stopped. As a result, the control unit 25 of the transmitter 2 switches the operation of the transmitter 2 from the first transmission mode to the second transmission mode, and repeatedly transmits a signal including information indicating the state of the tire 5 at the second time interval. .. Specifically, the control unit 25 of the transmitter 2 transmits a signal including information indicating the state of the tire 5 when it is determined that the second time has elapsed since the last signal was transmitted.

At the time point T7, the control unit 33 of the receiver 3 determines that the signal has not been continuously received for the second period after the second period has elapsed from the time when the signal was last received. As a result, the control unit 33 of the receiver 3 switches the operation of the receiver 3 from the first reception mode to the second reception mode. In this way, in the tire condition monitoring system 1, the transmitter 2 and the receiver 3 can switch their respective operations.

As described above, the tire condition monitoring system 1 according to the embodiment of the present invention is installed on the tire 5 of the vehicle 4, acquires information indicating the condition of the tire 5, and includes information indicating the condition of the tire 5. The receiver 3 includes a transmitter 2 that repeatedly transmits a signal and a receiver 3 that is installed in the vehicle body 4A of the vehicle 4 and receives the signal, and the receiver 3 has a first reception mode in which the signal can always be received. The operation can be switched between the second reception mode, which repeats a cycle consisting of a state in which the signal can be received and a state in which the signal cannot be received, and the operation can be continuously performed for a predetermined period during the operation in the first reception mode. It is configured to switch the operation to the second reception mode when the signal is not received. According to such a configuration, the receiver 3 can switch the operation mode based on the signal received from the transmitter without receiving the information from the device other than the transmitter 2. Therefore, in order to receive the information used by the receiver 3 for switching the operation mode from other in-vehicle devices such as the wheel speed sensor, it is not necessary to wire and connect the receiver 3 to the other in-vehicle device or the accessory power supply. Therefore, it is possible to reduce the power consumption while facilitating the installation of the tire condition monitoring system 1 in the vehicle 4.

In the tire condition monitoring system 1 according to the embodiment of the present invention, the transmitter 2 repeats the signal in the first transmission mode in which the signal is repeatedly transmitted at the first time interval and in the second time interval longer than the first time interval. The operation can be switched between the second transmission mode for transmission, and when it is determined that the vehicle 4 is stopped during the operation in the first transmission mode, the operation is switched to the second transmission mode. It is configured. According to this configuration, in the tire condition monitoring system 1, in a situation where the condition of the tire is unlikely to change, such as when the vehicle 4 is stopped, the transmission interval of the signal including the information indicating the condition of the tire 5 is lengthened. The power consumption of the transmitter 2 can be reduced.

In the tire condition monitoring system 1 according to the embodiment of the present invention, the transmitter 2 acquires information indicating the running state of the vehicle 4, and the speed of the vehicle 4 is continuously equal to or lower than a predetermined speed for the first period. In addition, it is preferable to determine that the vehicle 4 is stopped. According to such a configuration, in the tire condition monitoring system 1, the transmitter 2 can determine that the vehicle 4 is stopped with a simple configuration, and the tire condition monitoring system 1 can be provided at low cost. ..

In the tire condition monitoring system 1 according to the embodiment of the present invention, the data length of the signal transmitted in the second transmission mode is preferably longer than the data length of the signal transmitted in the first transmission mode. According to such a configuration, in the tire condition monitoring system 1, the receiver 3 can accurately receive the signal without failing to receive the signal even during the operation in which the power consumption is suppressed.

In the tire condition monitoring system 1 according to the embodiment of the present invention, the transmitter 2 operates in the first transmission mode when it is determined that the vehicle 4 is not stopped during the operation in the second transmission mode. The data length of the signal transmitted from the switch and the transmitter 2 is the data of the signal transmitted in the second transmission mode a predetermined number of times after the operation of the transmitter 2 is switched from the second transmission mode to the first transmission mode. It is preferably left long. According to this configuration, in the tire condition monitoring system 1, the operation of the transmitter 2 is switched from the second transmission mode to the first transmission mode, and the receiver 3 is switched from the second reception mode to the first reception mode. Even when a time lag occurs, the receiver 3 can accurately receive the signal without failing to receive it.

In the tire condition monitoring system 1 according to the embodiment of the present invention, the signal includes information indicating the operating state of the transmitter 2, and the receiver 3 receives the signal during the operation in the second receiving mode. When it is determined that the transmitter 2 is in the first transmission mode based on the information indicating the operation state of the transmitter 2 included in the above, it is preferable to switch the operation to the first reception mode. According to this configuration, in the tire condition monitoring system 1, when the receiver 3 determines that the frequency of receiving the signal increases, the receiver 3 receives the signal by changing the operation mode of the receiver 3. It can be received accurately without any loss. In particular, the receiver 3 receives the information used for the determination from the transmitter 2, and in order to acquire the information regarding the operating state of the vehicle 4, the receiver 3 is used as another in-vehicle device, an accessory power source, or the like. Since it is not necessary to connect by wiring, it is possible to facilitate the installation of the receiver 3 in the vehicle 4.

In the tire condition monitoring system 1 according to the embodiment of the present invention, the duration of one cycle in the second reception mode of the receiver 3 is the continuation of the signal transmitted by the transmitter 2 during the operation in the second transmission mode. It is preferably shorter than the time. According to such a configuration, in the tire condition monitoring system 1, the receiver 3 can accurately receive the signal transmitted by the transmitter 2 in the second transmission mode in the second reception mode without failing to receive the signal.

In the tire condition monitoring system 1 according to the embodiment of the present invention, the duration of the signal transmitted by the transmitter 2 during the operation in the second transmission mode is the continuation of one cycle in the second reception mode of the receiver 3. It is preferably 1.5 to 2 times the time. According to such a configuration, in the tire condition monitoring system 1, the receiver 3 can accurately receive the signal.

The receiver 3 according to the embodiment of the present invention is the receiver 3 included in the tire condition monitoring system 1 and has a first reception mode in which signals can always be received and a state in which signals can be received. When the operation can be switched between the second reception mode that repeats the cycle consisting of the following and the non-reception state, and the signal is not continuously received for a predetermined period during the operation in the first reception mode. It is configured to switch the operation to the second reception mode. According to such a configuration, the receiver 3 can switch the operation mode based on the signal received from the transmitter 2 without receiving the information from the device other than the transmitter 2. Therefore, in the tire condition monitoring system 1, the power consumption can be reduced while facilitating the installation of the receiver 3 in the vehicle 4.

The transmitter 2 according to the embodiment of the present invention is the transmitter 2 included in the tire condition monitoring system 1 from the first transmission mode in which signals are repeatedly transmitted at the first time interval and the first time interval. The operation can be switched between the second transmission mode in which the signal is repeatedly transmitted at a long second time interval, and when it is determined that the vehicle 4 is stopped during the operation in the first transmission mode, the first operation is performed. 2 It is configured to switch the operation to the transmission mode. According to such a configuration, in the tire condition monitoring system 1, the receiver 3 can switch the operation mode based on the signal received from the transmitter 2 without receiving information from a device other than the transmitter 2. can do. Therefore, it becomes easy to install the receiver 3 in the vehicle 4 in the tire condition monitoring system 1. Further, in the tire condition monitoring system 1, the power consumption of the transmitter 2 can be reduced.

Although the present invention has been described based on the drawings and embodiments, it should be noted that those skilled in the art can make various modifications and modifications based on the present invention. Therefore, it should be noted that these modifications and modifications are within the scope of the present invention. For example, the configurations or functions included in each embodiment or each embodiment can be rearranged so as not to be logically inconsistent. Further, the configurations or functions included in each embodiment can be used in combination with other embodiments or other embodiments, and a plurality of configurations or functions may be combined into one, divided into one, or one. It is possible to omit the part.

For example, in the above-described embodiment, all or part of the functions or processes described as the functions of the transmitter 2 or the functions of the receiver 3 may be realized by a program. The program can be recorded on a computer-readable non-temporary recording medium. The non-temporary recording medium that can be read by a computer is, for example, a magnetic recording device, an optical disk, an optical magnetic recording medium, or a semiconductor memory. The distribution of the program is carried out, for example, by selling, transferring, or renting a portable recording medium such as a DVD (digital versatile disc) or a CD-ROM (compact disc read only memory) in which the program is recorded. Alternatively, the program can be distributed by storing the program in the storage of a predetermined server and transferring the program from the predetermined server to another computer. The program may be provided as a program product.

The processor of the transmitter 2 or the receiver 3 temporarily stores, for example, a program recorded on a portable recording medium or a program transferred from a predetermined server in a memory. Then, the processor reads the program stored in the memory and executes the process according to the read program. The program includes information used for processing by the processor and equivalent to the program. For example, data that is not a direct command to the processor but has the property of defining the processing of the processor corresponds to "a program-like data".

Further, for example, in the above-described embodiment, all or a part of the functions or processes described as the functions or processes of the transmitter 2 may be realized as the functions or processes of the receiver 3. In such a case, a program describing the processing contents for realizing each function of the transmitter 2 according to the embodiment is stored in a memory or the like provided in the receiver 3, and the program is read and executed by the processor or the like of the receiver 3. May be good. Similarly, all or part of the function or process described as the function or process of the receiver 3 may be realized as the function or process of the transmitter 2.

Further, for example, in the above-described embodiment, the transmitter 2 includes a first sensor unit 21 and a second sensor unit 22, and the first sensor unit 21 acquires information indicating the state of the tire 5 and the second sensor. It has been described as assuming that the unit 22 acquires information indicating the traveling state of the vehicle 4. However, the transmitter 2 may acquire information indicating the state of the tire 5 and information indicating the running state of the vehicle 4 by one sensor. Alternatively, the transmitter 2 does not include the first sensor unit 21 or the second sensor unit 22, and is communicably connected to the first sensor unit 21 or the second sensor unit 22 installed on the tire 5, so that the tire can be used. Information indicating the state of 5 or information indicating the running state of the vehicle 4 may be acquired.

1: Tire condition monitoring system, 2: Transmitter, 21: 1st sensor unit, 22: 2nd sensor unit, 23: Communication unit, 24: Storage unit, 25: Control unit, 3: Receiver, 31: Communication unit 31, 32: Storage unit, 33: Control unit, 4: Vehicle, 4A: Body, 5: Tire, 6: In-vehicle device, 7: Battery

Claims (10)

A transmitter installed on a tire of a vehicle, which acquires information indicating the condition of the tire and repeatedly transmits a signal including information indicating the condition of the tire.
A receiver installed on the vehicle body and receiving the signal,
Including
The receiver is
The operation can be switched between the first reception mode in which the signal can always be received and the second reception mode in which the cycle consisting of a state in which the signal can be received and a state in which the signal cannot be received is repeated.
A tire condition monitoring system configured to switch the operation to the second reception mode when the signal is not continuously received for a predetermined period during the operation in the first reception mode. The transmitter is
The operation can be switched between the first transmission mode in which the signal is repeatedly transmitted at the first time interval and the second transmission mode in which the signal is repeatedly transmitted at a second time interval longer than the first time interval.
The tire condition monitoring system according to claim 1, wherein the operation is switched to the second transmission mode when it is determined that the vehicle is stopped during the operation in the first transmission mode. .. The transmitter is
Obtaining information indicating the running state of the vehicle,
The tire condition monitoring system according to claim 2, wherein when the speed of the vehicle is continuously equal to or lower than a predetermined speed for the first period, it is determined that the vehicle is stopped. The tire condition monitoring system according to claim 2 or 3, wherein the data length of the signal transmitted in the second transmission mode is longer than the data length of the signal transmitted in the first transmission mode. When the transmitter determines that the vehicle is not stopped during the operation in the second transmission mode, the transmitter switches the operation to the first transmission mode.
The data length of the signal transmitted from the transmitter is the data length of the signal transmitted in the second transmission mode a predetermined number of times after the operation of the transmitter is switched from the second transmission mode to the first transmission mode. The tire condition monitoring system according to claim 4, wherein the data length remains unchanged. The signal contains information indicating the operating state of the transmitter.
When the receiver determines that the transmitter is in the first transmission mode based on the information indicating the operating state of the transmitter included in the received signal during the operation in the second reception mode. The tire condition monitoring system according to any one of claims 2 to 5, wherein the operation is switched to the first reception mode. Any of claims 2 to 6, wherein the duration of one cycle of the receiver in the second receive mode is shorter than the duration of the signal transmitted by the transmitter during operation in the second transmit mode. The tire condition monitoring system described in item 1. The tire condition monitoring system according to claim 7, wherein the duration of the signal is 1.5 to 2 times the duration of the one cycle. A receiver included in the tire condition monitoring system according to any one of claims 1 to 8.
The operation can be switched between the first reception mode in which the signal can always be received and the second reception mode in which the cycle consisting of a state in which the signal can be received and a state in which the signal cannot be received is repeated.
A receiver configured to switch the operation to the second reception mode when the signal is not continuously received for a predetermined period during the operation in the first reception mode. A transmitter included in the tire condition monitoring system according to any one of claims 1 to 8.
The operation can be switched between the first transmission mode in which the signal is repeatedly transmitted at the first time interval and the second transmission mode in which the signal is repeatedly transmitted at a second time interval longer than the first time interval.
A transmitter configured to switch the operation to the second transmission mode when it is determined that the vehicle is stopped during the operation in the first transmission mode.

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