JP4778729B2 - Tire management system - Google Patents

Description

  The present invention includes a sensor module that is attached to the inside of a tire mounted on a vehicle and that measures a tire state quantity including tire internal pressure, and a receiving module that is attached to a vehicle body and receives the measurement data transmitted from the sensor module. It relates to the improvement of the tire management system.

  In order to manage the tire during operation, a sensor module that measures the tire state quantity such as the internal pressure and temperature of the tire is attached to the inside of the tire, and the measurement data from this sensor module is received by the receiving module on the vehicle body side, It has been proposed to install on a vehicle a tire management system configured to transmit the received data to a vehicle operation management center that manages a plurality of vehicles. Based on the above, if it is determined that there is a possibility that the vehicle may break down, the purpose is to prevent dangerous situations by instructing the driver from the vehicle operation management center It is. (For example, Patent Document 1).

  In such a tire management system, a data request signal is transmitted from each receiving module to a corresponding sensor module at a predetermined cycle, and the sensor module measures a tire condition amount in accordance with the timing at which the data request signal is received. And the measurement result is transmitted to the reception module, and the reception module can acquire measurement data from the sensor module in this way.

JP-A-10-104103

  Normally, a battery is incorporated in a sensor module as a power source for driving electronic components such as a sensor, a CPU, a transmitter / receiver transmitter, and the like provided therein. The sensor module is attached to the tire inner surface by, for example, baking, so that the sensor module does not drop or break due to vibration, tire deformation, or the like. In many cases, the battery is not replaced. Therefore, the life of the battery determines the life of the sensor module, and it has been important to keep the battery as long as possible. Of the processes performed by the sensor module, the process of transmitting data to the receiving sensor consumes the most electricity. As the number of measurement data transmissions per unit time increases, the battery consumption increases as much. Battery life will be shortened.

  Therefore, when the transmission cycle of the data request signal to the sensor module is T1, T1 is set to a large value in consideration of this. However, in this case, since the transmission cycle is long, the tire internal pressure When an abnormal condition such as a drop in the temperature occurs suddenly, there may be a case where a long time elapses until the abnormality is received by the receiving module. It was.

  The present invention has been made in view of such problems, and when an abnormal state occurs without sacrificing battery life, the receiving module can receive the abnormality without delay after the occurrence. An object of the present invention is to provide a tire management system that can be used.

<1> is a sensor module that is attached to the inside of a tire mounted on a vehicle, measures a tire state quantity, and transmits the measurement data to the vehicle body side; and the measurement that is provided on the vehicle body side and transmitted from the sensor module In a tire management system comprising a receiving module for receiving data,
The reception module transmits a data request signal for requesting transmission of the measurement data to the sensor module in the first period T1, and the sensor module relates to at least one tire state quantity in a first period shorter than the first period T1. Configured to perform a process of measuring the tire state quantity at a cycle T2 of 2,
The sensor module
For each of the measurements performed in the second cycle, a process is performed to determine whether the measured data is outside a predetermined normal range,
When it is determined that the data is out of the normal range, the abnormality flag is immediately set to a value indicating an abnormal state, and at this time, the number of continuous acquisitions of measurement data that is out of the normal range is determined in advance. If the received integer is less than or equal to the integer N1, transmission processing for transmitting the latest measurement data and abnormality flag data to the receiving module by the predetermined number N2 in the third period T3 shorter than the second period T2 is performed. Done
If it is determined that the data is within the normal range, a process for setting an abnormal flag to a value representing a normal state is performed,
When a reception of a data request signal from a reception module is detected, the tire management system is configured to immediately perform transmission processing for transmitting the latest measurement data and abnormality flag data to the reception module.

  <2> is a preferable item of <1>, and the integer N1 is smaller than (T1 / T2).

  <3> is a preferable one of <1> or <2>, and the sensor module includes a ROM that stores a limit value that defines the normal range.

  <4> is preferably any one of <1> to <3>. When the value of the abnormality flag indicates an abnormal state in the signal received from the sensor module, the reception module The transmission of the data request signal to the sensor module is configured to be transmitted at a cycle shorter than the first cycle.

  According to <1>, the sensor module measures the tire state quantity at a cycle T2 shorter than the transmission cycle T1 of the data request signal from the receiving module, determines whether this is a normal state or an abnormal state, and measures If the result is an abnormal state, the measurement data and the abnormal flag data are immediately transmitted to the receiving module, so that the data can be transmitted to the receiving module without delay after the abnormality occurs, and the tire state quantity is normal. In such a state, only the measurement data is transmitted to the receiving module at the same long cycle T1 as in the prior art, so that battery consumption is not greatly increased.

  According to <2>, since the maximum number of continuous transmissions N1 in the short cycle T2 of transmission based on the determination at the time of occurrence of abnormality is (T1 / T2), this transmission is performed over a long period of time longer than the long cycle T1. It is possible to prevent the battery from being consumed at an early stage, and when the tire is removed from the vehicle and stored in a state where the air is removed, the sensor module performs measurement at the second period T2. However, transmission processing is not performed, and this can also reduce battery consumption.

  According to <3>, the sensor module includes a ROM that stores a limit value that defines the normal range. First, the limit value is set in accordance with the size of the tire to which the sensor module is attached. In this case, the limit value is not rewritten, and strict air pressure management can be performed over a long period of time.

  According to <4>, if the value of the abnormality flag indicates an abnormal state in the signal received from the sensor module, the reception module transmits the data request signal to the sensor module next time. Since transmission is performed with a period shorter than the period, even if the data transmission from the sensor module in the second period T2 ends, if the abnormal state continues, it is shorter than the first period T1. The tire state quantity can be received in a cycle, and a quicker response to the abnormal state is possible.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a state where a sensor module is attached to a tire, and FIG. 2 is a schematic layout diagram illustrating a configuration of a tire management system. The sensor module 3 is attached to the inside of each tire T attached to the vehicle V.

  In the case shown in the drawing, the sensor module 3 is attached by being baked onto the inner surface of the tire T, and is provided so as not to be isolated or broken from the tire even if the running tire is deformed under load. The sensor module 3 includes a detection unit that detects tire internal pressure and the like, an antenna 3a and a transmitter that control transmission and reception with the reception module 1, and a control unit that controls these. As a detection means, what detects tire temperature besides tire internal pressure can also be included. The sensor module 3 attached to the inside of the tire T is attached to the wheel W in addition to the illustrated embodiment, or is held by a separate means in the tire internal pressure space surrounded by the tire T and the wheel W. It is also possible.

  The tire management system 10 is provided in the vehicle V, and the sensor module 3 attached to the inside of each tire T, the receiving module 1 that receives data from these sensor modules 3, and the receiving module 1 with the sensor module 3 Each receiving module 1 has a transmitter and an antenna 1a for transmitting and receiving to and from the corresponding sensor module 3.

  FIG. 3 is a flowchart showing processing of the sensor module 3. In step s1, the sensor module 3 performs a measurement process for measuring a tire state quantity such as an internal pressure of the tire at a time interval of the second period T2 (step s1). Next, in step s2, it is determined whether the measurement data is within the normal range (normal state) or not (abnormal state). If this is normal, the abnormality flag is set to 0 (step s3) and the n1 counter is set. Is cleared (step s4), and the operation for checking the presence / absence of a data transmission request signal from the receiving module is started (step s9).

  Here, the abnormality flag indicates whether the latest measurement data is in a normal state or an abnormal state. In this embodiment, when this is 1, it indicates an abnormal state, and when it is 0, it indicates a normal state. . The n1 counter is a counter representing the number of consecutive measurement results in an abnormal state. When the measurement data is in a normal state, the continuity is interrupted, and is initialized to 0 when the system is started in step s4. After (step s0), if the measurement result in the abnormal state is 1 or more due to continuous measurement, this is cleared.

  Further, the operation for checking the presence / absence of the data transmission request signal from the reception module 1 shown in step s9 is performed so that the data transmission request is checked only when the sleep and wakeup are repeated repeatedly at a predetermined cycle, for example. In this case, battery consumption can be suppressed only during the sleep time.

  In step s2, if the measurement data is in an abnormal state, the abnormal flag is set to 1 (step s5), and it is determined whether or not the number of continuous measurements (n1 + 1) in the abnormal state is N1 or less. (Steps 6 and 7) If the number of consecutive measurements (n1 + 1) is N1 or less, a transmission process for transmitting the abnormal flag data and the measurement data to the receiving module is performed (Step s8). The number of transmission processes is N2 times and the third period T3. In the figure, n2 represents a counter value of a counter for counting the number of transmission processes.

  Then, after completion of the N2 times of transmission processing, the operation for checking the presence or absence of the data transmission request signal from the reception module 1 is started (step s9).

  In step s9, when the sensor module 3 detects the data transmission request signal from the reception module 1, the sensor module 3 performs the transmission process of transmitting the latest measurement data and the abnormality flag data to the reception module 1 only once (step s10). . The measurement process (step s2) having the second period T2 is performed at an independent timing unrelated to the transmission process performed based on the data request from the reception module 1.

  Next, timing examples of the measurement process and transmission process of the sensor module 3 and the transmission process of the data request signal of the reception module 1 will be described. FIG. 4 is a timing chart showing an example of signal output of the sensor module and the receiving module when the tire state quantity changes from normal to abnormal. FIG. 5 is a chart showing an enlarged view of the signal D in FIG. 6 is an enlarged chart showing the signal C in FIG. 4, and FIG. 7 is an example of signal output of the sensor module and the receiving module when the tire state quantity returns from normal to a normal state after a slight lapse of an abnormal state. It is a timing chart which shows.

FIG. 4A is a timing chart showing the timing of the measurement process of the sensor module 3 in pulses as time on the horizontal axis, and the value of measurement data in each measurement process is represented by the height of the pulse. . In the figure, P _L is a limit value of the tire state quantity to be measured. For example, when the measured tire state quantity is the tire internal pressure, P _L is a lower limit value allowed as the tire internal pressure. An internal pressure below P _L is an abnormal condition. In the case of the example shown in FIG. 4A, the measurement data acquired after the measurement process with the sign “S” represents that it is continuously abnormal. The limit value of the normal range is stored in the ROM and cannot be easily rewritten.
Here, the measurement process is performed at a predetermined second period T2.

  FIG. 4B is a timing chart showing the transmission timing of the data request signal for requesting the sensor module 3 to transmit the measurement data from the receiving module 1, and the transmission period is the measurement process of the sensor module 3. It can be defined as the first period T1 independent of the timing, and the data request signal transmission process D is repeatedly performed at a time interval of the period T1.

  Here, the period T2 is set so as to be smaller than the period T1, and therefore, when the tire state quantity is normal, the measurement can be performed in a period shorter than the data transmission period, and the battery life can be reduced. It is possible to deal with sudden occurrence of abnormal conditions without sacrificing.

  FIG. 4C is a timing chart showing the timing at which the sensor module 3 performs transmission processing. When the sensor module 3 receives the data request signal from the receiving module 1, the sensor module 3 transmits the abnormal flag data and the measurement data. Although the process A is performed only once, if the measurement data is out of the normal range as a result of the measurement process performed in the cycle T2, the transmission process C is performed in addition to the transmission process A. This transmission process C is performed for a predetermined number of times N1, and thereafter, even if the measurement data acquired in the measurement process is abnormal, this transmission process is not performed as long as the abnormal state continues.

  On the other hand, after the transmission process C N1 times, the data request signal is transmitted from the reception module 1 to the sensor module 3 at the cycle T1, so that the sensor module 3 responds to the measurement data and the abnormality flag. A transmission process B for transmitting data is performed. Here, the transmission process B is distinguished from the transmission process A. In the transmission process A, the value of the abnormality flag transmitted is 0, whereas in the transmission process B, the value of the abnormality flag is 1. Therefore, the transmission process A and the transmission process B are different only in this point.

  As shown in FIG. 5, the data request signal D transmitted by the receiving module 1 is a collection of m1 (m2) single data request signals E transmitted in a predetermined cycle. If the data request signal E is not transmitted from the sensor module 3 within a predetermined time, the data request signal E is transmitted again and the data transmission from the sensor module 3 is awaited. In this way, the transmission operation of the data request signal E is continued until the data transmission from the sensor module 3 is confirmed. Therefore, the number m1 (m2) of data request signals E varies depending on whether or not data is transmitted from the sensor module.

  On the other hand, the transmission process C performed when the measurement data acquired by the sensor module 3 as a result of the measurement process is out of the normal range is a single process repeated at the third periphery T3 as shown in FIG. The transmission process F is gathered a predetermined number of times N2, and the greater the number of times, the higher the probability of reception by the receiving module, but the corresponding increase in battery consumption. It is preferable to set an optimum value.

  FIG. 4 shows the signal timing when the abnormal state continues for a long time after the normal state of the tire, but the abnormal state is short in a short period of time and when the normal state is restored, FIG. As shown in FIG. 4, even if the number of consecutive measurement data that becomes abnormal is less than the predetermined number N1, the transmission process C in the second cycle T2 is stopped. Then, the transmission process C in the second cycle T2 is not performed until the tire state quantity becomes an abnormal state again. This is to suppress battery consumption, and N1 is preferably set to (T1 / T2) or less, which is just enough to increase battery consumption even if N1 is further increased. This is because the effect cannot be expected.

  7A to 7C are diagrams showing examples of transmission timings different from those shown in FIGS. 4A to 4C. FIG. The timing of the measurement processing of the sensor module 3 is expressed in pulses on the axis, and a timing chart in which the height of the pulse is proportional to the value of the measurement data. FIG. On the other hand, FIG. 7C is a timing chart showing the transmission timing of the data request signal for requesting the transmission of measurement data, and FIG.

  Here, preferable examples of T1, T2, and T3 include those in which T1 is 10 minutes to 1 hour, T2 is 1/2 to 1/20 of T1, and T3 is 10 to 100 ms.

  Next, a modified example of the tire management system of the present invention will be described. In the above embodiment, as shown in FIG. 2, the receiving module 1 and its antenna 1a are arranged in the vicinity of the tire with the sensor module 3, but only the antenna 1a is arranged in the vicinity of the tire T. The receiving module 6 may be provided in the central control module 5A as shown in the schematic layout diagram of the configuration of the tire management system 10A of the modified example. The tire management system 10A is configured as shown in FIG. An antenna for disposing one or more receiving modules 6 inside 5A, further disposing an antenna switching means 7 between the receiving module 6 and the plurality of antennas 1a, and switching the antenna switching means 7 to connect to the receiving module 6. By selecting 1a, one or more (one in the illustrated case) receiving modules 6 common to these antennas 1a can be used for all antennas. It is configured to process signals from Na 1a. The antenna switching means 7 can be constituted by a wiring relay, a semiconductor switch, or the like. However, a port that is always connected to each antenna 1a is provided as hardware in the receiving module 6, and each port is opened and closed by software. You may comprise by what is performed in. When the receiving module is arranged in the vicinity of the tire, the receiving module is easily broken because the vicinity of the tire is a place where rocks and the like frequently fly when the vehicle travels. If only the antenna is placed near the tire and the receiving module is integrated with the central control module where rocks do not fly, the communication efficiency between the receiving module and the sensor module will not be sacrificed, and damage will be caused by flying rocks, etc. Damage can be minimized by limiting the possible parts to the antenna alone. Furthermore, the structure can be simplified by integrating the receiving module and the central control module.

The present invention can be used not only for a tire management system for construction vehicles but also for a system that manages tires that measure all types of tire condition information including those for passenger cars in real time.

It is sectional drawing shown in the state which attached the sensor module to the tire. 1 is a schematic layout diagram showing a configuration of a tire management system. It is a flowchart which shows the process of a sensor module. It is a timing chart which shows the example of the signal output of a sensor module and a receiving module when a tire state quantity changes from normal to abnormal. 5 is an enlarged chart of a signal D in FIG. 5 is an enlarged chart illustrating a signal C in FIG. It is a timing chart which shows the example of the signal output of a sensor module and a receiving module at the time of returning to normal, after a tire state quantity passes from an abnormal state for a while slightly. It is a schematic arrangement | positioning figure which shows the structure of the tire management system of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception module 1a Antenna of reception module 3 Sensor module 3a Antenna of sensor module 5, 5A Central control module 6 Reception module 7 Antenna switching means 10, 10A Tire information management system T Tire W Wheel

Claims (4)

A sensor module that is attached to the inside of a tire mounted on a vehicle, measures a tire state quantity, and transmits the measurement data to the vehicle body side, and a reception that is provided on the vehicle body side and receives the measurement data transmitted from the sensor module. In the tire management system with modules,
The reception module transmits a data request signal for requesting transmission of the measurement data to the sensor module in the first period T1, and the sensor module relates to at least one tire state quantity in a first period shorter than the first period T1. Configured to perform a process of measuring the tire state quantity at a cycle T2 of 2,
The sensor module
For each of the measurements performed in the second cycle, a process is performed to determine whether the measured data is outside a predetermined normal range,
When it is determined that the data is out of the normal range, the abnormality flag is immediately set to a value indicating an abnormal state, and at this time, the number of continuous acquisitions of measurement data that is out of the normal range is determined in advance. If the received integer is less than or equal to the integer N1, transmission processing for transmitting the latest measurement data and abnormality flag data to the receiving module by the predetermined number N2 in the third period T3 shorter than the second period T2 is performed. Done
If it is determined that the data is within the normal range, a process for setting an abnormal flag to a value representing a normal state is performed,
A tire management system configured to perform a transmission process of transmitting the latest measurement data and abnormality flag data to the reception module immediately upon detection of reception of a data request signal from the reception module.   The tire management system according to claim 1, wherein the integer N1 is smaller than (T1 / T2).   The tire management system according to claim 1, wherein the sensor module includes a ROM that stores a limit value that defines the normal range.   If the value of the abnormality flag in the signal received from the sensor module indicates an abnormal state, the reception module transmits a data request signal to the sensor module for the next time with a period shorter than the first period. The tire management system according to any one of claims 1 to 3, wherein the tire management system is configured.

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