JP2012158277A - Tire information detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly specify a failure part of a trigger machine on a receiver side, in a tire information detecting device for transmitting tire information such as tire air pressure to a vehicle body side receiver from a wheel side transmitter in response to a trigger signal from the trigger machine.SOLUTION: A control part 41 of an initiator driver 4 as the trigger machine transmits the trigger signal to the sensor transmitter 2 by adding failure part specifying information for specifying the failure part when detecting a failure of the initiator driver 4. A control part 21 of the sensor transmitter 2 transmits a response signal including the failure part specifying information to the receiver 3 when the failure part specifying information is added to the received trigger signal. A control part 31 of the receiver 3 stores the failure part specifying information in a memory 35 when the failure part specifying information is included in the received response signal.

Description

  The present invention relates to a tire information detection device for detecting a wheel mounting position and tire air pressure (tire information).

  One type of tire air pressure detection device is a direct type (see, for example, Patent Documents 1 and 2). In this type of tire pressure detecting device, a transmitter including a sensor such as a pressure sensor that outputs a signal corresponding to the tire pressure is wirelessly transmitted to the wheel provided with the tire. . A receiver that receives a signal from the transmitter is provided on the vehicle body side. Then, the tire air pressure is calculated based on the signal received by the receiver, and a warning is issued if the air pressure is reduced.

  Further, in Patent Document 1, even when the wheel position is changed, such as tire rotation, the wheel mounting position can be specified so that it can be determined to which wheel the signal from the transmitter is mounted. A tire pressure detecting device having a function is disclosed. In the tire air pressure detection device disclosed in Patent Document 1, a trigger machine that transmits a trigger signal is provided on the vehicle body side. The trigger machine is provided so that the distance to each transmitter attached to each wheel is different. In addition, the trigger device is connected to the receiver through a communication line so as to be communicable, and is configured to transmit a trigger signal based on an instruction from the receiver, for example.

  The trigger signal from the trigger device is received by each transmitter at a reception intensity corresponding to the transmission distance. In each transmitter, the reception intensity of the received trigger signal is calculated, and a response signal including the reception intensity is transmitted to the receiver. Then, based on the received intensity included in the response signal, it is determined from which transmitter the response signal is transmitted, that is, the mounting position of the wheel. That is, in the tire air pressure detection device of Patent Document 1, a response signal including a signal (reception intensity) corresponding to the position of the wheel is transmitted from the transmitter to the receiver in response to the trigger signal. Some tire pressure signals are transmitted from the transmitter to the receiver in response to the trigger signal.

Japanese Patent No. 4175348 JP 2006-175971 A

  By the way, in the tire information detection apparatus that detects the wheel mounting position and the tire air pressure in response to the trigger signal, the receiver is connected to the in-vehicle LAN, but the trigger device is not connected to the in-vehicle LAN. Therefore, when the communication line between the receiver and the trigger machine is disconnected, there is a problem that the receiver side cannot quickly grasp the state of the trigger machine. In particular, when the trigger machine is out of order, the failed part of the trigger machine cannot be quickly identified.

  The present invention has been made in view of the above problems, and even if a communication line between a receiver and a trigger machine is disconnected, a tire information detection device that can quickly identify a faulty part of the trigger machine on the receiver side. The issue is to provide.

In order to solve the above problems, the present invention provides a response signal provided on a wheel provided with a tire and including a signal corresponding to the position of the wheel or a signal corresponding to the air pressure of the tire in response to a trigger signal. A transmitter to transmit,
A trigger machine provided on the vehicle body side for transmitting the trigger signal;
In a tire information detection device comprising: a receiver provided on a vehicle body side, connected to be able to communicate with the trigger machine via a communication line, and receiving a response signal from the transmitter;
The trigger machine includes a failure part detection means for detecting a failure part of the trigger machine, and when the failure part detection means detects the failure part, it adds failure part specifying information for specifying the failure part. To send the trigger signal,
When the transmitter receives the trigger signal to which the failed part specifying information is added, the transmitter transmits a response signal including the failed part specifying information added to the trigger signal.

  According to this, since the trigger machine includes the failure part detection means for detecting the failure part of the trigger machine, when the trigger machine fails, the failure part is detected by the failure part detection means. And the failure part specific information which specifies the failure part is added to a trigger signal and a response signal, ie, is transmitted to a receiver via a transmitter. Therefore, even if the communication line between the receiver and the trigger machine is disconnected, the failure part of the trigger machine can be quickly specified based on the failure part specifying information on the receiver side.

  Further, the transmitter according to the present invention includes a disconnection detection unit that detects disconnection of the communication line, the failure part detection unit detects the failure part, and the disconnection detection unit detects the disconnection. The trigger signal to which the failure part specifying information is added is transmitted.

  If the communication line is not disconnected, the failure part of the trigger machine can be specified through the communication line. Therefore, it is preferable to transmit the failure part specifying information when the communication line is disconnected as described above.

1 is a block diagram showing a schematic configuration of a tire air pressure detection device 1. FIG. 4 is a flowchart of processing executed by a control unit 41 of the initiator driver 4. It is a flowchart of the process which the control part 21 of the sensor transmitter 2 performs. 2 is a diagram illustrating the configuration of a trigger signal 100 and a diagram illustrating the configuration of a response signal 200. FIG.

  Hereinafter, embodiments of a tire information detection device according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a tire air pressure detection device 1 to which a tire information detection device of the present invention is applied. The tire air pressure detecting device 1 is provided in the vehicle 6. The vehicle 6 is provided with wheels 61 provided with tires. Although only one wheel 61 is shown in FIG. 1, the vehicle 6 is provided with four wheels 61, that is, a driver seat side front wheel, a passenger seat side front wheel, a driver seat side rear wheel, and a passenger seat side rear wheel. It has been.

  As shown in FIG. 1, the tire air pressure detection device 1 includes a sensor transmitter 2, a receiver 3, an initiator driver 4, and a display 7. The sensor transmitter 2 also includes a battery (not shown), and each component is operated by the battery. The sensor transmitter 2 is attached to each wheel 61, and more specifically, for example, is attached to an air injection valve in the wheel of each wheel 61. The sensor transmitter 2 includes a control unit 21, a sensing unit 22, a receiving unit 23, a receiving antenna 24, a transmitting unit 25, and a transmitting antenna 26.

  The sensing unit 22 outputs a signal (detection signal) corresponding to the tire air pressure, and is composed of, for example, a strain gauge type, a diaphragm type, or a semiconductor type pressure sensor. The sensing unit 22 is connected to the control unit 21, and the detection signal output from the sensing unit 22 is input to the control unit 21.

  The receiving unit 23 receives a trigger signal transmitted from the initiator driver 4 described later via the receiving antenna 24. The receiving unit 23 includes a demodulation circuit that demodulates the received LF band trigger signal into a signal that can be read by the control unit 21. The receiving unit 23 is connected to the control unit 21, and a trigger signal received by the receiving unit 23 is input to the control unit 21.

  The transmission unit 25 includes a modulation circuit that modulates the response signal transmitted from the control unit 21 into a signal in the RF band (for example, 315 MHz band), and wirelessly transmits the modulated response signal from the transmission antenna 26 as an RF radio wave. To do.

  The control unit 21 includes a CPU, a ROM, a RAM, and the like, and the CPU executes predetermined processing according to a program stored in the ROM. Specifically, when receiving the trigger signal from the receiving unit 23, the control unit 21 receives the detection signal from the sensing unit 22, generates a response signal including the detection signal, and transmits the response signal to the transmission unit. To 25. That is, the response signal including the detection signal is transmitted to the transmission unit 25. The response signal is composed of a plurality of frames, and the detection signal of the sensing unit 22 is stored in one of these frames. Further, in another frame of the response signal, ID information for identifying which wheel 61 is the response signal attached to, or the reception intensity of the trigger signal (the attachment position of the wheel 61 as in Patent Document 1). And the like) are stored as necessary. When storing the reception intensity in the frame of the response signal, the control unit 21 executes a process for calculating the reception intensity of the trigger signal received from the reception unit 23.

  Moreover, the control part 21 of each sensor transmitter 2 is comprised so that a response signal may be transmitted, for example, shifting timing. For this purpose, for example, the transmission timing for transmitting the response signal after several seconds after receiving the trigger signal is set differently for each sensor transmitter 2 in advance.

  As described above, the control unit 21 is configured to transmit a response signal in response to the trigger signal. In addition to this, the sensing unit is determined every predetermined period (for example, every minute) by its own determination. It may be configured to transmit 22 detection signals. The sensor transmitter 2 corresponds to the “transmitter” in the present invention.

  The receiver 3 is provided on the vehicle body side of the vehicle 6 and includes a control unit 31, a reception unit 32, an interface unit 33, a reception antenna 34, and a memory 35. The receiving unit 32 receives an RF radio wave response signal from the sensor transmitter 2 via the receiving antenna 34. The receiving unit 32 includes a demodulation circuit that demodulates the received response signal into a signal that can be read by the control unit 31. The receiving unit 32 is connected to the control unit 31, and a response signal received by the receiving unit 32 is input to the control unit 31. The receiving antenna 34 is one or more common antennas that collectively receive response signals from the sensor transmitters 2 and is fixed to the vehicle body of the vehicle 6.

  The interface unit 33 is an interface for communicating with the initiator driver 4 to be described later. The interface unit 33 transmits a signal sent from the control unit 31 to the initiator driver 4 and receives a signal sent from the initiator driver 4. Send to control unit 31. In the present embodiment, the interface unit 33 is a UART (Universal Asynchronous Receiver Transmitter) interface. The receiver 3 and the initiator driver 4 are connected by a communication line 5, and communication between the receiver 3 and the initiator driver 4 is performed via the communication line 5.

  The memory 35 stores various types of information based on instructions from the control unit 31, and for example, a flash memory or a hard disk device is used. In the present embodiment, the memory 35 stores failure site specifying information for specifying the failure site of the initiator driver 4.

  The control unit 31 includes a CPU, a ROM, a RAM, and the like, and the CPU executes predetermined processing according to a program stored in the ROM. Specifically, the control unit 31 instructs the initiator driver 4 to transmit a trigger signal. The command timing may be, for example, a predetermined periodic timing or a timing at the time of vehicle inspection at a dealer or the like. Moreover, when the control unit 31 receives a response signal from the sensor transmitter 2, the control unit 31 calculates the tire pressure based on the detection signal of the sensing unit 22 included in the response signal. Then, when the tire air pressure is smaller than a predetermined threshold value, the control unit 31 displays a warning on the display 7 that the tire air pressure has decreased. When a body ECU or a meter ECU is interposed between the receiver 3 and the display unit 7, the control unit 31 causes the display unit 7 to display a decrease in tire air pressure via the body ECU or the meter ECU. become.

  In addition, when the response signal from the sensor transmitter 2 includes the reception intensity of the trigger signal, the control unit 31 sends the response signal sent to any of the four wheels 61 based on the reception intensity. The wheel position detection which identifies whether it is the thing of the sensor transmitter 2 attached to is performed. For the details of this wheel position detection method, for example, the method of Patent Document 1 is used.

  The receiver 3 having the above configuration is connected to the in-vehicle LAN 8 and can communicate with various devices through the in-vehicle LAN 8. For example, when a tire pressure diagnostic tool is connected to the in-vehicle LAN 8 by a dealer or the like, the control unit 31 of the receiver 3 detects the tire pressure or specifies the wheel position based on the command of the diagnostic tool. Execute the process.

  The display device 7 is disposed at a place where the driver can visually recognize, and is configured by an alarm lamp disposed in an instrument panel of the vehicle 6, for example. When the signal indicating that the tire air pressure has decreased is sent from the control unit 31 of the receiver 3, the display device 7 displays the fact to notify the driver of the decrease in the tire air pressure.

  The initiator driver 4 corresponds to a “trigger machine” in the present invention, and transmits a trigger signal based on a command from the control unit 31 of the receiver 3. The initiator driver 4 is provided on the vehicle body side of the vehicle 6, specifically, for example, at the same position as in Patent Document 1, that is, at a different distance from all four wheels 61 (strictly speaking, a transmission antenna 43 described later). Are provided at different distances from all four wheels 61). When the tire air pressure detection device 1 does not perform wheel position detection based on the reception intensity of the trigger signal, the initiator driver 4 may not be provided at a position different from all the wheels 61. The initiator driver 4 may be a single one that collectively transmits a trigger signal to each sensor transmitter 2, or a plurality of initiator drivers 4 may be provided for each sensor transmitter 2. When the initiator driver 4 is provided for each sensor transmitter 2, each initiator driver 4 is provided, for example, near the sensor transmitter 2 (wheel 61) in charge of each initiator driver 4. The initiator driver 4 is connected to the receiver 3 through the communication line 5 but is not connected to the in-vehicle LAN 8.

  The initiator driver 4 includes a control unit 41, a transmission unit 42, a transmission antenna 43, and an interface unit 44. The transmission unit 42 is a part that generates a trigger signal of a predetermined intensity based on a command from the control unit 41 and wirelessly transmits the trigger signal from the transmission antenna 43 as an LF radio wave (for example, a 125 kHz band radio wave). The transmission antenna 43 is composed of one or a plurality of antennas, and is an antenna that transmits the trigger signal generated by the transmission unit 42. FIG. 1 illustrates an example in which the transmission antenna 43 includes two transmission antennas 43a and 43b. In this case, for example, one transmission antenna 43a is fixed to the front of the vehicle 6 (position close to the front wheel 61), and the other transmission antenna 43b is fixed to the rear of the vehicle 6 (position close to the rear wheel 61). Note that as many transmission antennas as the number of sensor transmitters 2 may be provided. In this case, each transmission antenna is fixed near the sensor transmitter 2 in charge. Further, when the initiator drivers 4 are provided as many as the number of sensor transmitters 2, each initiator driver 4 is provided with one transmission antenna.

  The interface unit 44 is an interface for communicating with the receiver 3 and is a UART interface similarly to the interface unit 33 of the receiver 3.

  The control unit 41 includes a CPU, a ROM, a RAM, and the like, and the CPU executes a predetermined process according to a program stored in the ROM. Specifically, the control unit 41 is a part that comprehensively controls the trigger signal to be transmitted to the sensor transmitter 2, and determines, for example, the transmission intensity of the trigger signal or the transmission timing of the trigger signal. . As the transmission timing, the control unit 41 determines a transmission timing that is determined based on a command from the receiver 3. The trigger signal transmitted from the control unit 41 is composed of a plurality of frames.

  Further, the control unit 41 constitutes a “failed part detecting means” in the present invention and has a function of detecting a failed part of the initiator driver 4. Specifically, for example, it is possible to detect a failure in each of the above components (the transmission unit 42, the transmission antenna 43, and the interface unit 44). In addition to the transmission unit 42, the transmission antenna 43, and the interface unit 44, the control unit 41 can also detect a failure in a peripheral circuit constituting the initiator driver 4, and further, a configuration in the control unit 41 (connected to the CPU). ROM, RAM, etc.) can also be detected. As a method for detecting a faulty part, for example, a method of monitoring the terminal voltage of each part connected to the control unit 41 is used. That is, when the terminal voltage indicates an abnormal voltage, the control unit 41 determines (identifies) that the portion connected to the terminal indicating the abnormal voltage has failed. In addition to the method of monitoring the terminal voltage, the control unit 41 employs a method of determining that the part has failed when the part that has been commanded to perform a specific action does not perform a desired action, for example. Also good.

  As described above, since the initiator driver 4 is not connected to the in-vehicle LAN 8, if the communication line 5 is temporarily disconnected, the state of the initiator driver 4 cannot be quickly grasped on the receiver 3 side. In particular, when the initiator driver 4 fails, failure analysis cannot be performed quickly. Therefore, in the tire air pressure detection device 1 of the present invention, when the initiator driver 4 fails, failure part specifying information for specifying the failure part is transmitted to the receiver 3 via the sensor transmitter 2. The processing at that time will be described below with reference to the flowcharts of FIGS. FIG. 2 shows a flowchart of processing executed by the control unit 41 of the initiator driver 4, and FIG. 3 shows a flowchart of processing executed by the control unit 21 of the sensor transmitter 2. 2 and 3 is started, for example, when the ignition switch of the vehicle 6 is turned on, and is repeatedly executed at predetermined intervals.

  First, the control unit 41 of the initiator driver 4 determines whether or not the initiator driver 4 has failed (S11 in FIG. 2). If there is no failure (S11: No), the process of the flowchart of FIG. 2 is terminated. On the other hand, if a failure of the initiator driver 4 is detected (S11: Yes), the process proceeds to S12. In S12, it is determined whether or not the communication line 5 is disconnected (S12). Specifically, when the control unit 41 attempts to communicate with the receiver 3 and the communication cannot be performed, it is determined that the communication line 5 is disconnected (S12). In addition, the control part 41 which performs the process of S12 is equivalent to the "disconnection detection means" in this invention. When the communication line 5 is not disconnected (S12: No), it is determined whether or not the communication line 5 is disconnected again at the next time (S12). That is, it is continuously monitored whether the communication line 5 is disconnected (S12). When the communication line 5 is disconnected (S12: Yes), the trigger signal to which the failure part specifying information for specifying the failure part is added is transmitted to the sensor transmitter 2 (S13). Here, FIG. 4A is a diagram illustrating the configuration of the trigger signal 100 in S13. FIG. 4A shows an example in which the trigger signal 100 is composed of a plurality of frames 101 to 106. The failure part specifying information is stored in any one of the frames 101 to 106 of the trigger signal 100 (frame 105 in FIG. 4A). The other frames 101 to 104 and 106 store the same information as the trigger signal transmitted when the initiator driver 4 is not malfunctioning. After the process of S13, the process of the flowchart of FIG.

  On the other hand, on the sensor transmitter 2 side, it is first determined whether or not a trigger signal has been received (S21 in FIG. 3). If the trigger signal has not been received (S21: No), the process of the flowchart of FIG. 3 is terminated. On the other hand, when the trigger signal is received (S21: Yes), the process proceeds to S22. In S22, it is determined whether or not failure part specifying information is added to the received trigger signal (S22). When the failure part specifying information is not added (S22: No), a normal response signal, that is, a response signal including the detection intensity of the sensing unit 22 and the reception intensity of the trigger signal is transmitted to the receiver 3 ( S24). In this case, a normal trigger signal is transmitted from the initiator driver 4 separately from the processing of FIG. After the process of S24, the process of the flowchart of FIG.

  On the other hand, when failure part specific information is added to the trigger signal (S22: Yes), the process proceeds to S23. In S23, a response signal including the failure part specifying information is transmitted to the receiver 3 (S23). Note that the failure part specifying information included in the response signal may not be completely the same information as the failure part specifying information added to the trigger signal, and any information can be used as long as it is information that can specify the failure part on the receiver 3 side. It may be processed. Here, FIG. 4B is a diagram illustrating the configuration of the response signal 200 in S23. FIG. 4B shows an example in which the response signal 200 is composed of a plurality of frames 201 to 206. Fault site identification information is stored in any frame of response signal 200 (frame 205 in FIG. 4B). In the other frames 201 to 204 and 206, for example, information similar to a response signal (such as a detection signal of the sensing unit 22) transmitted when the initiator driver 4 is not out of order is stored. In S23, a response signal including only the failure part specifying information may be transmitted. After the process of S23, the process of the flowchart of FIG.

  When a response signal including failure part specifying information is transmitted in S23, the response signal is received by the receiver 3. Then, the failure part specifying information is extracted from the response signal by the control unit 31 of the receiver 3 and stored in the memory 35. As a result, the receiver 3 side can identify the failed part of the initiator driver 4 at any time by referring to the failed part specifying information stored in the memory 35. Therefore, for example, when a failure analysis tool is connected to the in-vehicle LAN 8 by a dealer or the like and the failure analysis of the initiator driver 4 is performed, the failure portion of the initiator driver 4 can be quickly identified, and as a result, replacement or repair of the failure portion can be performed. Can be done quickly.

  Note that the tire information detection device according to the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the scope of the claims. For example, in the above embodiment, when the initiator driver 4 fails and the communication line 5 is disconnected, the failure part specifying information is transmitted to the receiver 3 via the sensor transmitter 2. When a failure occurs, the failure site specifying information may be transmitted regardless of whether the communication line 5 is disconnected. As a result, the receiver 3 can grasp the failure of the initiator driver 4 more quickly, and can identify the failure portion of the initiator driver 4.

  In FIG. 2 of the above embodiment, the failure of the initiator driver 4 is first determined (S11), and then the disconnection of the communication line 5 is determined (S12), but in what order these processes of S11 and S12 are performed. It may be executed with. In the above embodiment, the failure part specifying information is stored in the memory 35. In addition to this, the failure part specified by the failure part specifying information is notified to the driver by the display 7 or the like. good.

DESCRIPTION OF SYMBOLS 1 Tire pressure detection apparatus 2 Sensor transmitter 21 Control part 3 Receiver 31 Control part 35 Memory 4 Initiator driver 41 Control part 42 Transmission part 43 Transmission antenna 44 Interface part 5 Communication line 6 Vehicle 61 Wheel 7 Indicator 8 In-vehicle LAN

Claims (2)

A transmitter provided on a wheel provided with a tire and transmitting a response signal including a signal corresponding to the position of the wheel or a signal corresponding to the pressure of the tire in response to a trigger signal;
A trigger machine provided on the vehicle body side for transmitting the trigger signal;
In a tire information detection device comprising: a receiver provided on a vehicle body side, connected to be able to communicate with the trigger machine via a communication line, and receiving a response signal from the transmitter;
The trigger machine includes a failure part detection means for detecting a failure part of the trigger machine, and when the failure part detection means detects the failure part, it adds failure part specifying information for specifying the failure part. To send the trigger signal,
When the transmitter receives the trigger signal to which the failed part specifying information is added, the transmitter transmits a response signal including the failed part specifying information added to the trigger signal. Detection device. The transmitter includes a disconnection detection unit that detects disconnection of the communication line, and the faulty part identification unit detects the faulty part when the faulty part detection unit detects the faulty part and the disconnection detection unit detects the disconnection. The tire information detection device according to claim 1, wherein the trigger signal to which information is added is transmitted.

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