JP4984901B2 - Wheel condition monitoring system - Google Patents

Description

  The present invention relates to a wheel state monitoring system for monitoring a wheel state.

  In recent years, in order to realize safer vehicle driving, tire pressure monitoring system (TPMS: Tire Pressure Monitoring System) has been developed to notify the driver by wirelessly transmitting information such as tire pressure and temperature to the vehicle body. It has been. In such a tire air pressure monitoring system, a wheel state detection unit for detecting a wheel state such as tire air pressure is provided for each wheel. The wheel state information detected by the wheel state detection unit is wirelessly transmitted to the vehicle body side.

Regarding this type of monitoring system, in Patent Document 1, in response to a transmission request from a vehicle-mounted machine, each tire-mounted machine does not overlap the transmission timing of the pneumatic signal with the transmission timing of other tire-mounted machines. A technique for controlling transmission timing is disclosed. Patent Document 2 discloses a technique for controlling transmission from a sensor unit by trigger signal transmitting means provided corresponding to the sensor unit of each tire. Patent Document 3 discloses a technique for controlling each tire. A technique is disclosed in which a trigger signal transmitter is arranged in the vicinity so that the transmission timing of each tire from the transmitter is different.
JP 2004-322926 A JP 2004-161245 A JP 2004-262324 A

  According to the techniques disclosed in Patent Documents 2 and 3, although the transmission timing from each tire transmitter can be shifted, a trigger signal transmitter is provided corresponding to each tire, resulting in high cost. Moreover, according to the technique disclosed in Patent Document 1, all tire mounting machines respond to a single transmission request from the vehicle body mounting machine. For example, it is desired to acquire sensor information of only a specific wheel. In this case, sensor information from other wheels is not necessary, and transmission power is wasted. In particular, since the tire mounting machine is battery-driven, it is preferable to reduce power consumption as much as possible.

  This invention is made | formed in view of such a subject, The objective is to provide the technique which can acquire wheel state information efficiently from the wheel state detection unit provided in the wheel.

In order to solve the above problems, a wheel state monitoring system according to an aspect of the present invention is provided corresponding to each of a plurality of wheels, and a plurality of wheel state detections that wirelessly transmit the detected wheel state as wheel state information. Each of the plurality of wheel state detection units has a set number of times assigned to be different from each other in the storage unit, and when the number of times the trigger signal is received is the set number of times, the wheel A plurality of wheel state detection units that transmit state information; a vehicle body side receiver that is provided in a vehicle body to which the plurality of wheels are mounted; and that receives the wheel state information transmitted wirelessly from the wheel state detection unit; A trigger signal transmitter that is provided in the vehicle body and transmits a trigger signal wirelessly. The trigger signal transmitter periodically changes the number of times the trigger signal is transmitted within a predetermined time. The wheel state detection unit includes a detecting means for detecting a wheel state, and a wheel side for receiving the trigger signal. A receiver, a timer that counts a predetermined time when the wheel-side receiver receives the trigger signal, a number-counting unit that counts the number of times the trigger signal is received by the wheel-side receiver, and a count by the number-of-times measuring unit A wheel-side transmitter that transmits wheel state information when the number of times is a set number of times, and the number-of-times measuring means is a trigger signal at the wheel-side receiver during counting of the predetermined time by the timer. The wheel-side transmitter increments the number of counts, and the number of times counted by the number-of-times counting means at the end of timing by the timer is the set number of times. When the, it transmits the wheel state information to the vehicle body side receiver.

According to this aspect, each of the plurality of wheel state detection units transmits the wheel state information to the vehicle body side receiver based on the number of times the trigger signal has been received. The transmission timing from the detection unit can be controlled. Further, it is possible to avoid a situation in which each of the plurality of wheel state detection units transmits the wheel state information at the same timing, and the vehicle body side receiver can suitably receive the wheel state information. In addition, the number of trigger signal receptions can be suitably counted. In addition, by counting the number of trigger signal receptions within a predetermined time and building a system that transmits wheel state information when the number of counts when the predetermined time elapses is a set number, only a specific wheel state detection unit Therefore, it is possible to transmit the wheel state information.

  According to the present invention, wheel state information can be efficiently acquired from a wheel state detection unit provided on the wheel.

  FIG. 1 is a diagram schematically illustrating a wheel state monitoring system 200 provided in the vehicle 10 according to the embodiment. The vehicle 10 includes a vehicle main body 12, and the vehicle main body 12 includes a right front wheel 14FR, a left front wheel 14FL, a right rear wheel 14RR, and a left rear wheel 14RL (hereinafter collectively referred to as “wheel 14” as necessary). Installed. The wheel 14 has a tire and a wheel, and a wheel rim formed in a cylindrical shape is provided on the outer periphery of the wheel, and the tire is assembled on the outer periphery of the wheel rim. Thus, a tire air chamber is formed in a region surrounded by the inside of the tire and the outer periphery of the wheel rim.

  The wheel state monitoring system 200 of the present embodiment includes a wheel state detection unit 16a, 16b, 16c, 16d (hereinafter collectively referred to as “wheel state detection unit 16” as necessary), a vehicle body side receiver 18, and an ignition switch 20. , A trigger signal transmitter 22, a wheel speed sensor 24, and an electronic control unit (hereinafter referred to as “ECU”) 100. The wheel state detection unit 16a is mounted on the right front wheel 14FR, the wheel state detection unit 16b is mounted on the left front wheel 14FL, the wheel state detection unit 16c is mounted on the right rear wheel 14RR, and the wheel state detection unit 16d is mounted on the left rear wheel 14RL. .

  The wheel state detection unit 16 has a tire valve and a unit main body. The unit main body has a battery and a base therein, and a processing device to be described later is provided on the base. In addition to this, the unit main body includes an air pressure sensor, a temperature sensor, a transmitter, a receiver, and the like which will be described later. A processing apparatus produces | generates wheel state information from detection results, such as an air pressure sensor and a temperature sensor. The battery supplies power to a base processing device or the like. For this reason, the wheel state detection unit 16 can detect the tire air pressure and the tire chamber temperature and transmit the wheel state information without receiving power from the vehicle body 12. The unit main body is fixed to one end of the tire valve. The wheel state detection unit 16 is attached to the wheel 14 by fixing the tire valve to the wheel rim.

  The vehicle body side receiver 18, the ignition switch 20, the trigger signal transmitter 22, the wheel speed sensor 24, and the ECU 100 are provided in the vehicle body 12. The vehicle body side receiver 18 receives the wheel state information transmitted wirelessly from the wheel state detection unit 16. The vehicle body side receiver 18 is connected to the ECU 100, and wheel state information received by the vehicle body side receiver 18 is output to the ECU 100. The trigger signal transmitter 22 is connected to the ECU 100 and transmits a trigger signal wirelessly based on an instruction from the ECU 100. The transmitted trigger signal is received by the receiver of the wheel state detection unit 16 provided in each wheel 14.

  The ignition switch 20 is turned from an off state by turning a key by a driver, and starts the engine of the vehicle body 12. The ECU 100 detects whether the ignition switch 20 is on or off. The wheel speed sensor 24 detects the rotation of each of the four wheels 14 and detects the wheel speed that is the rotation speed of each of the four wheels 14.

  FIG. 2 is a functional block diagram of the wheel state detection unit 16 according to the present embodiment. The wheel state detection unit 16 includes a wheel-side transmitter 50, a wheel-side receiver 52, an air pressure sensor 54, a temperature sensor 56, and a processing device 60.

  The air pressure sensor 54 and the temperature sensor 56 are detection means for detecting the wheel state, respectively. The air pressure sensor 54 detects the air pressure in the tire chamber (hereinafter referred to as “tire air pressure”), and the temperature sensor 56 is the tire air pressure. Detect room temperature. The air pressure sensor 54 and the temperature sensor 56 are connected to the processing device 60, and the detection results from the air pressure sensor 54 and the temperature sensor 56 are output to the processing device 60. The wheel side transmitter 50 transmits the wheel state information to the vehicle body side receiver 18, and the wheel side receiver 52 receives the trigger signal transmitted from the trigger signal transmitter 22.

  The processing device 60 is configured by a microprocessor, and includes an information processing unit 62, a number counting unit 64, a timer 66, a transmission control unit 68, and a storage unit 70. The timer 66 measures time. The storage unit 70 stores a unit ID used as identification information for uniquely identifying the wheel state detection unit 16. The information processing unit 62 uses the detection results of the air pressure sensor 54 and the temperature sensor 56 to acquire tire air pressure information and tire air chamber temperature information (hereinafter also referred to as “tire air pressure information etc.”). The information processing unit 62 generates wheel state information including the acquired tire air pressure information and tire air chamber temperature information. The wheel state information is configured in a predetermined data format including the unit ID, and is transmitted from the wheel-side transmitter 50 in response to a transmission instruction from the transmission control unit 68.

  In the wheel state monitoring system 200 of this embodiment, each of the plurality of wheel state detection units 16 receives wheel state information from the wheel side transmitter 50 based on the number of times the trigger signal is received by the wheel side receiver 52. It has a function of transmitting to the receiver 18. Thereby, the environment where the transmission timings from the wheel state detection unit 16 do not overlap each other can be created, and the transmission intervals of the plurality of wheel state detection units 16 can be controlled from the ECU 100. Each wheel state detection unit 16 holds the set number of times assigned to be different from each other in the storage unit 70, and when the number of times the trigger signal is received by the wheel side receiver 52 is the set number of times, The transmitter 50 transmits wheel state information. The set number of times assigned differently is preset in the wheel state detection unit 16 as a condition for transmitting the wheel state information from the wheel side transmitter 50 and is grasped by the ECU 100 on the vehicle body 12 side. Therefore, the ECU 100 can individually acquire the wheel state information from the wheel state detection unit 16 mounted on the desired wheel 14 by controlling the number of trigger signals to be transmitted.

  For example, the wheel state detection unit 16a of the right front wheel 14FR is assigned one set number of times, and the wheel state detection unit 16b of the left front wheel 14FL is assigned twice the set number of times to detect the wheel state of the right rear wheel 14RR. The unit 16c is assigned three set times, and the wheel state detection unit 16d of the left rear wheel 14RL is assigned four set times. When the vehicle main body 12 is equipped with a spare tire, the spare tire wheel state detection unit 16 may be assigned a set number of five times. Each wheel state detection unit 16 counts the number of times the trigger signal is received, and transmits the wheel state information when the counted number is the set number. By assigning different set times to each wheel state detection unit 16, it is possible to avoid a situation in which wheel state information is transmitted from a plurality of wheel state detection units 16 at the same timing, and from the ECU 100, the wheel state of a specific wheel 14 It is possible to instruct the transmission of information.

  The number counting unit 64 counts the number of times the trigger signal is received by the wheel side receiver 52. At this time, the number measuring unit 64 counts the number of times the trigger signal is received from when the wheel side receiver 52 receives the trigger signal until a predetermined time elapses. The predetermined time may be about several seconds. The count value is set to 0 before the trigger signal reception count starts. When the timer 66 receives the trigger signal in the wheel side receiver 52, the timer 66 measures a predetermined time. Specifically, when the wheel side receiver 52 receives the trigger signal when the count value is 0, the number counting unit 64 increments the count value (that is, the count value is 1), and the timer 66 starts the timing operation. An instruction is sent, and the timer 66 starts a timing operation for a predetermined time. If the wheel-side receiver 52 further receives a trigger signal while the timer 66 is measuring the predetermined time, the number counting unit 64 increments the count value. When the timer 66 finishes the timing operation for a predetermined time, the timer 66 notifies the count measuring unit 64 of the end of the timing operation, and the count measuring unit 64 stops the increment operation.

  The transmission control unit 68 monitors the number of counts by the number counting unit 64 and acquires a count value when a predetermined time has elapsed. The transmission control unit 68 reads the set number of times stored in the storage unit 70 and supplies a transmission instruction to the wheel side transmitter 50 when the count value is the set number of times. The wheel side transmitter 50 transmits the wheel state information generated by the information processing unit 62 based on the transmission instruction to the vehicle body side receiver 18. The count measuring unit 64 returns the count value to 0 when the count value at the end of the timing operation is delivered to the transmission control unit 68.

  As described above, when the wheel side receiver 52 receives the trigger signal when the count value by the number counting unit 64 is 0, the timer 66 starts the time counting operation, and when the count value is a value other than 0, Even when the side receiver 52 receives the trigger signal, the time-counting operation being executed is reset and a new time-measurement operation is not started. Thereby, it is possible to accurately measure the predetermined time after starting the timer.

  For example, the number counting unit 64 may control the time counting operation of the timer 66 using a timer execution flag. Specifically, when the wheel side receiver 52 receives the trigger signal when the count value is 0, the number counting unit 64 sets the timer execution flag from OFF to ON, and instructs the timer 66 to start the time measuring operation. Send. After the predetermined time has elapsed, the number counting unit 64 is notified of the end of the time measuring operation, and sets the timer execution flag to off. In response to reception of the trigger signal, the number measuring unit 64 can send a timer 66 start instruction to the timer 66 only when the timer execution flag is set to OFF. This makes it possible to accurately measure the predetermined time without resetting the timing operation before the predetermined time elapses from the timer activation.

  FIG. 3 is a functional block diagram of the vehicle main body 12 in the wheel state monitoring system 200. The vehicle main body 12 includes a vehicle body side receiver 18, an ignition switch 20, a trigger signal transmitter 22, a wheel speed sensor 24, and an ECU 100. The ECU 100 includes a vehicle state determination unit 80 that determines the vehicle state, a transmission control unit 82 that controls the transmission operation of the trigger signal transmitter 22, an information analysis unit 84 that analyzes the wheel state information received by the vehicle body side receiver 18, and reception. A storage unit 86 for storing data and various tables is provided.

  The vehicle state determination unit 80 determines whether the vehicle is in a state that requires monitoring of tire pressure information and the like. For example, immediately after the engine is started or when the traveling state becomes high speed traveling, the vehicle state determination unit 80 determines that the tire pressure information and the like should be monitored. Specifically, when the vehicle state determination unit 80 detects that the ignition switch 20 is turned on, or detects that the vehicle is traveling at a high speed from the wheel speed detected by the wheel speed sensor 24, the tire pressure information or the like. It is determined that it is necessary to monitor the trigger signal transmitter 22, and an operation instruction for the trigger signal transmitter 22 is sent to the transmission control unit 82. When receiving an operation instruction from the vehicle state determination unit 80, the transmission control unit 82 controls the transmission operation of the trigger signal transmitter 22 so as to transmit a trigger signal according to a predetermined pattern.

FIG. 4 is a diagram for explaining the trigger signal transmission timing. Trigger signal transmitter 22, an instruction from the transmission control unit 82, the period the number of originations within a predetermined time T ₂ (T ₁₎ to vary. That is, in the first period, and once the number of originations within a predetermined time period T _2, in a subsequent period, the number of originations twice, three times, by four times, all mounted on the vehicle body 12 A trigger signal toward the wheel 14 is transmitted. When there is a spare tire, the number of transmissions is set to 5 times. Note that the specific number of times is according to the above-described example, and it goes without saying that the number of times is not limited to these numerical values.

Wheel state detection unit 16, after receiving the first trigger signal, monitors the trigger signal to be transmitted to the predetermined time T _2. Note that the first trigger signal means a signal transmitted at the beginning of each cycle in FIG. All wheel state detection unit 16, for receiving a first trigger signal at substantially the same timing, the timing of the monitoring period of the predetermined time T ₂ is completed also substantially equal. Wheel state detection unit 16, since it has a function of transmitting the wheel state information based on the number of times of receiving the trigger signal to a predetermined time T _2, after a predetermined time T _2, 1 single wheel state detection unit Wheel state information is transmitted from only 16. In the trigger signal transmission example shown in FIG. 4, the wheel state information is transmitted in the order of the wheel state detection unit 16a, the wheel state detection unit 16b, the wheel state detection unit 16c, and the wheel state detection unit 16d in successive cycles. The vehicle body side receiver 18 receives the transmitted wheel state information, and the information analysis unit 84 analyzes the wheel state information. The storage unit 86 holds an ID correspondence table that describes the correspondence between the unit ID and the mounting position of the wheel 14, and the information analysis unit 84 refers to the ID correspondence table and detects the wheel state information that transmitted the wheel state information. The attachment position of the unit 16 can be specified.

  For example, when the information analysis unit 84 determines that the tire pressure of a specific wheel 14 is low, the transmission control unit 82 further determines the number of tires assigned to the wheel 14 in order to reconfirm the tire pressure. The trigger signal may be transmitted from the trigger signal transmitter 22.

  FIG. 5 shows a transmission number table stored in the storage unit 86. In the transmission frequency table, the wheel position is associated with the transmission frequency for the wheel position. From this number-of-transmissions table, for example, it is derived that the number of transmissions of the left front wheel 14FL is two.

  When it is determined from the analysis result by the information analysis unit 84 that the air pressure of the left front wheel 14FL is low, the transmission control unit 82 refers to the transmission number table and sends a trigger signal to the trigger signal transmitter 22 for a predetermined time. Instruct to send twice. Thereby, the wheel state detection unit 16b mounted on the left front wheel 14FL responds and can transmit the wheel state information. Thus, the wheel state monitoring system 200 can send a wheel state information transmission instruction to the specific wheel state detection unit 16 only by controlling the number of trigger signals transmitted within a predetermined time.

  FIG. 6 shows a flow of wheel state information transmission processing. When the wheel side receiver 52 monitors the trigger signal (N in S10) and receives the trigger signal (Y in S10), the number counting unit 64 increments the count value from 0 to 1 (S12). The number measurement unit 64 sends a timer 66 start instruction to the timer 66, and the timer 66 starts the timer operation (S14). Subsequently, the wheel-side receiver 52 monitors the trigger signal (N in S16), and when receiving the trigger signal (Y in S16), increments the count value by one. During the time measurement by the timer 66 (N in S20), this increment process is continued. When the timing operation by the timer 66 ends (Y in S20), the transmission control unit 68 determines whether the count value at that time is equal to the set number of times that constitutes the transmission condition (S22). When the count value is equal to the set number of times (Y in S22), the wheel side transmitter 50 transmits the wheel state information to the vehicle body side receiver 18 (S24). On the other hand, if the count value is not equal to the set number of times (N in S22), the wheel state information is not transmitted. This flow ends when the count value is set to 0 (S26).

In the processing device 60, the wheel-side receiver 52 maintains a standby state in order to monitor the trigger signal, but the wheel-side transmitter 50 preferably normally maintains a power saving state. For example, the wheel-side transmitter 50 upon receiving the trigger signal at the wheel side receiver 52 is activated in the active state, after a predetermined time T _2, when they are not responding are also shifted to the power saving state. If a response is to be made, the wheel state information may be transmitted and then shifted to the power saving state. Thereby, it becomes possible to suppress the consumption of a battery.

  The present invention is not limited to the above-described embodiments, and any combination of the elements of the embodiments as appropriate is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to the embodiments based on the knowledge of those skilled in the art, and embodiments to which such modifications are added can be included in the scope of the present invention. Here are some examples.

  For example, in the embodiment, when a spare tire is also included, one set number of times from 1 to 5 is assigned to the wheel state detection unit 16 of each wheel 14. A plurality of consecutive set times may be assigned.

  FIG. 7 shows the correspondence between the wheel state detection unit and the assigned set number of times. The wheel state detection unit 16a of the right front wheel 14FR is assigned 1 to 3 times, and the wheel state detection unit 16b of the left front wheel 14FL is assigned 4 to 6 times, and the wheel of the right rear wheel 14RR is assigned. The state detection unit 16c is assigned a set number of 7 to 9 times, and the wheel state detection unit 16d of the left rear wheel 14RL is assigned a set number of times of 10 to 12. When the vehicle body 12 is equipped with a spare tire, the spare tire wheel state detection unit 16 may be assigned a set number of 13 to 15 times.

  In the example shown in FIG. 7, a plurality of consecutive setting times are assigned to each wheel state detection unit 16, and the setting times are continued so as not to be interrupted between the wheel state detection units. That is, the set number of times assigned to all the wheel state detection units 16 is a continuous number of 1 to 12 times, and each wheel state detection unit 16 is assigned three consecutive set times. As described above, it is preferable that the set number of times allocated not only within the wheel state detection unit 16 but also between the wheel state detection units is continued.

  FIG. 8 shows a transmission frequency table when a set number of times is assigned to each wheel state detection unit 16 as shown in FIG. In the transmission frequency table, the wheel position is associated with the transmission frequency for the wheel position. From this transmission number table, for example, it is derived that the number of transmissions of the trigger signal to the left front wheel 14FL is six.

  Since the wheel state monitoring system 200 monitors the wheel state even when the vehicle 10 is traveling at a high speed, it is conceivable that the reception of the trigger signal may occur in the wheel state detection unit 16. In such a case, as shown in FIG. 7, by assigning a set number of times to each wheel state detection unit 16, even if some of the trigger signals cannot be received, the desired wheel state detection unit 16 Can respond. In the example shown in FIG. 7 and FIG. 8, since reception of two trigger signals at maximum is allowed, even if the reception state in the wheel state detection unit 16 is bad, the intended wheel state detection unit 16 Can respond.

Further, the transmission timing of each wheel state detection unit 16 may be set in advance to one another differently from the timing for the monitoring period of the predetermined time T ₂ has ended. Thus, by varying the transmission timing from the timing of the monitoring period has ended for a predetermined time T _2, wants also no wheel state detection unit 16 in a case in response, transmits the wheel state detection unit 16 to respond Interference with can be avoided.

It is a figure which shows typically the wheel state monitoring system provided in the vehicle which concerns on an Example. It is a functional block diagram of the wheel state detection unit according to the present embodiment. It is a functional block diagram of the vehicle main body in a wheel state monitoring system. It is a figure for demonstrating the transmission timing of a trigger signal. It is a figure which shows the transmission frequency table stored in the memory | storage part. It is a figure which shows the flow of the transmission process of wheel state information. It is a figure which shows a response | compatibility with a wheel state detection unit and the allocated setting frequency | count. It is a figure which shows the transmission frequency table at the time of assigning a setting frequency with respect to each wheel state detection unit as shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle, 12 ... Vehicle main body, 14 ... Wheel, 16 ... Wheel state detection unit, 18 ... Vehicle body side receiver, 20 ... Ignition switch, 22 ... Trigger signal Transmitter, 24 ... wheel speed sensor, 50 ... wheel side transmitter, 52 ... wheel side receiver, 54 ... air pressure sensor, 56 ... temperature sensor, 60 ... processing device, 62 ... Information processing unit, 64 ... Counting unit, 66 ... Timer, 68 ... Transmission control unit, 70 ... Storage unit, 80 ... Vehicle state determination unit, 82 ... Transmission control unit, 84 ... information analysis unit, 86 ... storage unit, 100 ... ECU, 200 ... wheel state monitoring system.

Claims (3)

A plurality of wheel state detection units provided corresponding to each of the plurality of wheels and wirelessly transmitting the detected wheel state as wheel state information , wherein each of the plurality of wheel state detection units is different from each other. A plurality of wheel state detection units that transmit wheel state information when the assigned number of times is stored in the storage unit and the number of times the trigger signal is received is the number of times set ,
A vehicle body-side receiver that is provided on a vehicle body to which the plurality of wheels are mounted, and that receives wheel state information transmitted wirelessly from the wheel state detection unit;
A trigger signal transmitter that is provided in the vehicle body and transmits a trigger signal wirelessly, and the trigger signal transmitter periodically changes the number of times the trigger signal is transmitted within a predetermined time;
The wheel state detection unit includes:
Detecting means for detecting a wheel state;
A wheel side receiver for receiving the trigger signal;
A timer for measuring a predetermined time when the wheel-side receiver receives a trigger signal;
Number-of-times measuring means for counting the number of times the trigger signal is received in the wheel side receiver;
When the number of times counted by the number-of-times measuring means is a set number of times, a wheel-side transmitter that transmits wheel state information,
The number-of-times counting means increments the number of counts when receiving a trigger signal at the wheel side receiver during the measurement of the predetermined time by the timer,
The wheel-side transmitter transmits wheel state information to the vehicle-body-side receiver when the number of times counted by the number-of-times measuring means at the end of timing by the timer is a set number of times. Wheel condition monitoring system. It said frequency measurement means, the wheel condition monitoring system according to claim 1, characterized in that return after the count end of the predetermined time by the timer, the count number to zero. 3. The wheel state according to claim 2, wherein the timer starts a counting operation for the predetermined time when the wheel-side receiver receives a trigger signal when the number of times counted by the number-of-times counting means is 0. 4. Monitoring system.

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