JP2005170274A - Wheel state detecting device, wheel, and vehicle body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transmit wheel state information detected by a sensor only when a request is issued from a vehicle body side. <P>SOLUTION: This wheel state detecting device 10 comprises a plurality of wheel side communication sections 40 for transmitting a frame signal including a wheel state detected by the sensor 30 disposed in each wheel 20 and an identification code of the sensor, and a vehicle body side communication section 60 for receiving the frame signal. The wheel state detecting device 10 further comprises a start command means for simultaneously transmitting a start command signal to the plurality of wheel side communication sections 40, a receiving means for receiving the frame signal transmitted from the plurality of wheel side communication sections 40 in response to the start command signal, and a standby command means for simultaneously transmitting a standby command signal to the plurality of wheel side communication sections 40 when sensor identification codes of which number is the same as that of previously recorded sensors are received. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wheel state detection device that transmits a wheel state amount detected by a sensor and a sensor identification code to the outside of the wheel.

  In order to drive the vehicle safely, it is necessary to keep the state of the wheels including the tires normal. Therefore, when an abnormality such as insufficient tire air pressure occurs in the wheel, it is necessary to promptly detect this and take appropriate measures.

Conventionally, it has a tire pressure sensor provided on the wheel and a wireless transmission means for wirelessly transmitting a sensor detection signal, and an abnormality is detected by directly detecting the tire pressure of each wheel by the sensor and wirelessly transmitting it to the vehicle body side. A direct tire pressure detecting device is known. Patent Document 1 discloses a technique in which a tire identification code and an output value of an air pressure sensor are placed in the same frame and transmitted to the vehicle body side in such a tire air pressure detecting device.
JP 2000-23615 A

  In some prior arts, when different types of sensors are provided in one tire, different channels are used for different types of sensors to transmit and receive tire state values detected by the sensors. If it does in this way, when the number of sensors provided in a tire increases with the intelligence of a wheel from now on, there is a possibility that the number of channels may become insufficient in the future. Even when the same channel is used, a plurality of tire state values must be transmitted in association with one tire identification code, which complicates the data communication procedure and adds a new sensor. Changing the settings at times is complicated. Furthermore, since it is difficult to supply electric power from the outside to the wheel side sensor and communication device, it is necessary to cover the electric power with a battery, and in order to improve maintainability, the electric power consumption of the wheel side device is suppressed. There is a need.

  The present invention has been made in view of these points, and its purpose is to stop transmission from the wheel side when it is determined that the wheel state information has been received from all the sensors provided on the wheel. An object of the present invention is to provide a wheel state detection device that reduces the number of communication times and communication time.

  In order to solve the above-described problem, an aspect of the present invention includes a plurality of wheel-side communication units that transmit a frame signal including wheel state information detected by a sensor provided on each wheel and an identification code of the sensor. A wheel state detection device including a communication unit outside the wheel that receives the frame signal is provided. The wheel state detection device includes a start command means for simultaneously transmitting a start command signal to the plurality of wheel side communication units, and a frame signal transmitted from the plurality of wheel side communication units in response to the start command signal. And a standby command means for simultaneously transmitting standby command signals to the plurality of wheel side communication units when receiving the same number of identification codes as the number of sensors registered in advance.

  Here, the “start command signal” is a signal for restarting the device in the reception standby state, and the “standby command signal” is a signal for shifting the device in the operation state to the reception standby state. . “Wheel state information” refers to a physical quantity that represents the state of the wheel, and includes, for example, tire pressure, tire temperature, acceleration, and strain.

  According to this aspect, when the wheel state information is required in the communication unit outside the wheel, the wheel side communication unit is activated to start transmission of the frame signal, and it is determined that the wheel state information about all the sensors can be obtained. At this point, the transmission of the frame signal from the wheel side communication unit is stopped, so the number of communication times and communication time are reduced, and the power consumption of the wheel side communication unit can be reduced. The determination of the acquisition of the wheel state information is performed by receiving the same number of sensor identification codes as the number of sensors registered in advance in the communication unit outside the wheel. Therefore, it is possible to add a new sensor to the wheel simply by changing the number of registered sensors in the communication unit outside the wheel. Note that one or a plurality of sensors may be provided for each wheel. When there are a plurality of sensors, the frame signal is configured and transmitted for each sensor.

  The wheel side communication unit and the communication unit outside the wheel may transmit and receive the frame signal, the start command signal, and the standby command signal all on the same channel. By doing so, the number of channels is not insufficient even when the number of sensors provided on the wheels is increased. In addition, the start command signal and the standby command signal can be simultaneously transmitted to all the wheel side communication units.

  The standby command means may transmit a standby command signal when a predetermined time has elapsed since the start command signal was transmitted. As a result, even if the communication unit outside the wheel cannot receive the same number of sensor identification codes as the number of sensors registered in advance due to a failure of the sensor, a failure of the wheel side communication unit, noise, etc., the wheel side communication unit transmits the frame signal. Transmission is not continued and power consumption can be reduced.

  The communication unit outside the wheel is, for example, a vehicle body side communication unit provided in a vehicle body. The communication unit outside the wheel may be provided in a factory, a maintenance shop, a parking lot, or the like.

  The present invention can also be expressed as an aspect viewed from a wheel or a vehicle body. One aspect thereof is a wheel including a sensor provided on each wheel and a wheel side communication unit that transmits a frame signal including wheel state information detected by the sensor and an identification code of the sensor. In this case, the receiving means for receiving the start command signal transmitted from the communication unit outside the wheel, the frame transmitting means for transmitting the frame signal in response to the start command signal, and the same number as the number of sensors registered in advance. Standby shift means for shifting to a reception standby state in response to a standby command signal transmitted when the identification code is received by the communication unit outside the wheel.

  Still another aspect of the present invention provides a vehicle body side that receives a frame signal including wheel state information detected by a sensor provided on each wheel and an identification code of the sensor from a wheel side communication unit provided on the wheel side. The vehicle body includes a communication unit. In this case, the vehicle body receives start command means for simultaneously transmitting start command signals to the plurality of wheel side communication units, and frame signals transmitted from the plurality of wheel side communication units in response to the start command signals. Receiving means, and standby command means for simultaneously sending standby command signals to the plurality of wheel side communication units when receiving the same number of identification codes as the number of sensors registered in advance.

  The aspect of the wheel and the aspect of the vehicle body also have the same operations and effects as the wheel state detection device, and similar modifications are also within the scope of the present invention.

  According to the wheel state detection device of the present invention, when the communication unit outside the wheel receives the sensor identification codes for all the sensors, the standby command signal is transmitted to the wheel side communication unit, so the number of communication times and the communication time are reduced. Thus, the power consumption of the wheel side communication unit can be reduced.

  In one embodiment of the present invention, in a wheel state detection device including a wheel side communication unit and a vehicle body side communication unit, an activation command signal is simultaneously transmitted from the vehicle body side communication unit to each wheel side communication unit. It is activated to transmit a frame signal, and when receiving the same number of sensor identification codes as the number of sensors registered in advance, the transmission of the frame signal from the wheel side communication unit is stopped.

  FIG. 1 shows an overall configuration of a vehicle including a wheel state detection device 10 according to an embodiment of the present invention. Each of the four wheels of the vehicle is provided with a state quantity sensor that detects a state quantity of the wheel to be monitored, a wheel side communication unit that transmits wheel state information detected by the state quantity sensor to the vehicle body side, and an antenna. ing. The wheels are mainly composed of tires and wheels. The wheel of the first wheel 20a is provided with a first state quantity sensor 30a, a first wheel side communication unit 40a, and a first antenna 50a. The wheel of the second wheel 20b is provided with a second state quantity sensor 30b, a second wheel side communication unit 40b, and a second antenna 50b. The wheel of the third wheel 20c is provided with a third state quantity sensor 30c, a third wheel side communication unit 40c, and a third antenna 50c. The wheel of the fourth wheel 20d is provided with a fourth state quantity sensor 30d, a fourth wheel side communication unit 40d, and a fourth antenna 50d.

  Hereinafter, the first wheel 20a, the second wheel 20b, the third wheel 20c, and the fourth wheel 20d are collectively referred to as “wheel 20”, and the first state quantity sensor 30a, the second state quantity sensor 30b, and the third state quantity. The sensor 30c and the fourth state quantity sensor 30d are collectively referred to as “state quantity sensor 30”. In addition, the first wheel side communication unit 40a, the second wheel side communication unit 40b, the third wheel side communication unit 40c, and the fourth wheel side communication unit 40d are collectively referred to as “wheel side communication unit 40”, and the first antenna. 50a, the second antenna 50b, the third antenna 50c, and the fourth antenna 50d are collectively referred to as a “wheel-side antenna 50”.

  The state quantity sensors 30 in the present embodiment are generic names of sensors that detect one physical quantity, and as an example, may be a TPMS (Tire Pressure Monitoring System) sensor that detects tire air pressure as monitoring information. In addition, sensors for detecting various states such as temperature, contact surface wet / dry information, tire wear, acceleration, and strain can be provided. In FIG. 1, one state quantity sensor 30 is provided for each wheel. However, as will be described later, according to the present embodiment, the necessary number of state quantity sensors according to the number of state quantities to be monitored. 30 can be provided on the wheel 20.

  Each state quantity sensor 30 sends the detected wheel state information to the corresponding wheel side communication unit 40. The wheel side communication unit 40 is attached to the inside of the wheel, for example. Each wheel side communication unit 40 transmits the received wheel state information to the antenna 78 on the vehicle body side via the corresponding wheel side antenna 50. In addition, in FIG. 1, although the wheel side communication part 40 is shown as one for each wheel, you may provide multiple according to the number of state quantity sensors provided in a wheel. The state quantity sensor 30 and the wheel side communication unit 40 are driven using a battery (not shown) as a power source.

  The vehicle body side communication unit 60 receives wheel state information from the four wheel side communication units 40 via the antenna 78 on the vehicle body side. In addition, although the wheel side communication part 40 and the vehicle body side communication part 60 are each provided with the communication circuit, CPU, and memory, these structures are mentioned later. The vehicle body side communication unit 60 is driven using a battery (not shown) included in the vehicle body as a power source.

  The vehicle body side communication unit 60 sends the received wheel state information to an electronic control unit (hereinafter referred to as “ECU”) 80. The ECU 80 determines the state of the wheel 20 based on the wheel state information. The ECU 80 turns on the warning lamp 72 when the state of the wheel 20 is reduced to a warning level, such as when the temperature of the wheel 20 exceeds a predetermined value or the air pressure of the wheel 20 falls below a predetermined value. The driver is notified by causing the buzzer 74 to sound a warning sound.

  FIG. 2 is a diagram illustrating the internal configuration of the wheel side communication unit 40 and the vehicle body side communication unit 60 in the wheel state detection device 10. Each block shown here can be realized in hardware by an element such as a CPU and a memory of a computer, a communication circuit, and a mechanical device, and in software by a computer program or the like. It is drawn as a functional block realized by the cooperation. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by a combination of hardware and software.

  Wheel state information detected by the state quantity sensor 30 provided on the wheel is supplied to the frame transmission unit 42 of the wheel side communication unit 40. The frame transmission unit 42 includes a memory (not shown) that stores a sensor identification code (hereinafter referred to as “sensor ID”) for uniquely identifying all the state quantity sensors 30 provided in the vehicle. Yes. The sensor ID is, for example, 256 from 0 to 255, and is given by serial numbers for all the state quantity sensors. By making the sensor ID a serial number, it becomes easy to add a new state quantity sensor to the wheel. The sensor ID is registered in the frame transmission unit 42 when the tire is first attached to the vehicle body at the factory or when the tire is changed (rotated).

  The frame transmission unit 42 refers to this memory, configures the wheel state information and the corresponding sensor ID as one frame, and wirelessly transmits this frame to the vehicle body side communication unit 60. The frame transmission unit 42 configures and transmits a separate frame for each state quantity sensor 30 regardless of how many state quantity sensors 30 are provided on one wheel 20. Therefore, when one wheel 20 is provided with a plurality of state quantity sensors 30, a plurality of types of frame signals are transmitted from one wheel-side communication unit 40. The reason for transmitting in separate frames in this way is that the possibility of data interference decreases by shortening the frame length. The transmission of the frame signal from the frame transmission unit 42 is repeated until a standby command signal is received from the vehicle body side communication unit 60.

  FIG. 3 shows a data format of a frame signal transmitted from the frame transmission unit 42. A start bit for synchronization is provided at the head of the frame. The start bit is followed by a sensor ID for identifying the source state quantity sensor, and then wheel state information detected by the state quantity sensor is arranged. Since the sensor ID is given as a serial number as described above, the data length is determined. When the data length of the wheel state information differs depending on the type of the state quantity sensor, a bit indicating the start of data or a bit for notifying the data length may be added. An end bit may be added to prevent collision during transmission.

  The frame reception unit 62 of the vehicle body side communication unit 60 receives the frame signal transmitted from the frame transmission unit 42 via the antenna 78, and acquires the sensor ID included in this signal. The frame receiving unit 62 sets a flag corresponding to the sensor ID, and stores a frame signal corresponding to the sensor ID received for the first time in response to the current start command signal in a memory (not shown). FIG. 4 schematically shows this operation. The frame reception unit 62 is provided with the same number of flags as the number of state quantity sensors registered in advance. Since a flag is set for a sensor ID that has already been received, a frame that includes a sensor ID that is not flagged is stored in the memory, and a frame that includes a sensor ID that is flagged is discarded without being stored in the memory. . Therefore, when the same number of sensor IDs as the number of state quantity sensors registered in advance are stored in the memory, that is, when all the flags are set, frame signals from all the sensors mounted on the vehicle are received. It becomes possible to judge. Thus, the frame signal repeatedly transmitted until the standby command signal is received can be stored only once for one state quantity sensor.

  The number of state quantity sensors in the frame receiving unit 62 is set when a tire is first attached to the vehicle body at the factory or when a tire is replaced (rotated).

  When the frames for all the state quantity sensors are stored in the frame receiving unit 62, the standby command unit 64 sends a standby command signal for instructing to stop the transmission of the frame signal and enter the reception standby state to all the wheels. Simultaneously transmit to the communication unit 40. When receiving the standby command signal, the command receiving unit 46 of the wheel side communication unit 40 instructs the frame transmitting unit 42 to stop the transmission of the frame signal. Further, the standby state transition unit 44 turns off the supply of power from the battery to each state quantity sensor 30 and puts the wheel side communication unit 40 in the reception standby state until the activation command signal is received from the activation command unit 66. Transition.

  The frame signal received by the frame receiving unit 62 is passed to the ECU 80. The ECU 80 compares the sensor ID in the frame signal with the sensor ID registered in advance in the memory, and at which position the received wheel state information is, that is, any of the left front wheel, right front wheel, left rear wheel, and right rear wheel. Determine whether the tires are related to. ECU80 determines the state of each wheel based on the wheel state information which specified the position. For example, if the state value detected by the state quantity sensor is tire pressure, the state value is compared with a predetermined threshold value. If there is an abnormality, the buzzer 74 or the warning lamp 72 is used to check the tire pressure. Notify the driver of the abnormality.

  5 and 6 are flowcharts illustrating communication logic between the wheel side communication unit 40 and the vehicle body side communication unit 60. FIG. First, the start command unit 66 in the vehicle body side communication unit 60 sends a start command signal for requesting the wheel side communication units 40 of all the wheels mounted on the vehicle to transmit the wheel state information and the sensor ID. Transmit (S10). Subsequently, the vehicle body side communication unit 60 enters a receivable state, and the frame reception unit 62 receives the frame signal transmitted from the wheel side communication unit 40 (S12). Next, the frame receiving unit 62 determines whether or not the same number of sensor IDs as the number of state quantity sensors registered in advance have been received (S14). This determination is made based on, for example, whether all the above flags are set.

  When the same number of sensor IDs as the number of registered sensors has not been received (NO in S14), the frame receiving unit 62 determines whether or not a predetermined time set in advance has elapsed since the start command signal was transmitted. (S16). If the predetermined time has not elapsed (NO in S16), the frame receiving unit 62 continues to receive the frame signal.

  When the frame reception unit 62 has received the same number of sensor IDs as the number of registered sensors (YES in S14), it can be determined that the reception of frame signals for all the state quantity sensors has been completed. A standby command signal is transmitted to all the wheel side communication units 40 so as to shift to the reception standby state (S18). Even when a predetermined time has elapsed since the start command signal was transmitted in S16 (YES in S16), the standby command unit 64 similarly transmits a standby command signal (S18). This means that if the sensor IDs of all the state quantity sensors cannot be obtained even after a predetermined time, the state quantity sensor 30 or the wheel side communication unit 40 has failed or some state that prevents communication has occurred. Since it is considered, it is performed in order to avoid useless power consumption in the wheel side communication unit 40. At this time, a warning lamp 72 or buzzer 74 may be used to issue an alarm notifying the occurrence of an error.

  Next, a flowchart of the wheel side communication unit 40 will be described with reference to FIG. The wheel side communication unit 40 is normally in a reception standby state, and does not detect the wheel state by the state quantity sensor 30 unless it receives an activation command signal (NO in S20). When the command receiving unit 46 receives an activation command signal from the vehicle body side communication unit 60 (YES in S20), detection by the state quantity sensor 30 is started, and the frame transmission unit 42 includes the sensor ID and the wheel stored in the memory. The state information is formed into a frame and transmitted to the vehicle body side communication unit 60 (S22). Next, the command receiving unit 46 of the wheel side communication unit 40 determines whether or not a standby command signal has been received (S24). When the command receiving unit 46 has not received the standby command signal (NO in S24), the process returns to S22, and the frame transmitting unit 42 continues to transmit the frame signal. When the frame receiving unit 42 has received the standby command signal (YES in S24), the standby state transition unit 44 stops transmission of the frame signal and shifts the wheel side communication unit 40 to the reception standby state (S26). .

  Conventionally, when different types of sensors are provided in one tire, there are those that use a different channel for each type of sensor to transmit and receive the tire condition value detected by the sensor. If the number increases, the number of channels may be insufficient. Further, since it is necessary to change the channel in order to receive the data of each sensor, it takes time to receive. In addition, when a sensor is newly added, the setting of the channel of the transceiver must be changed, and there is a problem that the operation becomes complicated.

  As described above, in this embodiment, in order to determine that the frame signals for all the state quantity sensors 30 have been received, the frame reception unit 62 in the vehicle body side communication unit 60 includes the number of state quantity sensors. The same number of flags corresponding to the serial numbers may be prepared, and the sensor IDs of the state quantity sensors provided on the wheels may be registered in the frame transmission unit 42 in the wheel side communication unit 40. Therefore, even when the number of sensors provided on the wheels is increased, the setting can be easily changed within the range of the number of flags prepared in advance in the frame reception unit 62. Further, since the frame signal, the start command signal, and the standby command signal are all transmitted and received through the same channel, it is not necessary to set the channel in the vehicle body side communication unit. Furthermore, since there is no restriction on the number of channels, the total number of state quantity sensors and the degree of freedom of the number of state quantity sensors for each wheel are increased.

  In addition, according to this embodiment, the activation command to all the wheel side communication units 40 is performed all at once, and the sensor ID and the wheel state information are transmitted in one frame, so that communication is simplified. . Furthermore, since the frame signal is transmitted only when the vehicle body side communication unit 60 requests, regular communication from the wheel side communication unit 40 is not required, and the power consumption can be reduced.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications thereof are also included in the scope of the present invention. For example, a communication unit having the same function as the vehicle body side communication unit described above may be provided in a factory, a maintenance shop, a parking lot, or the like.

It is a whole block diagram of the wheel state detection apparatus which concerns on one Embodiment of this invention. It is a block diagram of the wheel side communication part and vehicle body side communication part of FIG. It is a figure which shows the data structure of the flame | frame transmitted for every state quantity sensor. It is a conceptual diagram of the mode of the storage of the sensor identification code in a frame receiver. It is a flowchart of operation | movement of a wheel side communication part. It is a flowchart of operation | movement of a vehicle body side communication part.

Explanation of symbols

  10 wheel state detection device, 20 wheels, 30 state quantity sensor, 40 wheel side communication unit, 42 frame transmission unit, 44 standby state transition unit, 46 command reception unit, 50 wheel side antenna, 60 vehicle body side communication unit, 62 frame reception , 64 standby command section, 66 start command section, 78 vehicle body side antenna, 80 ECU.

Claims (10)

A plurality of wheel side communication units that transmit a frame signal including wheel state information detected by sensors provided on each wheel and an identification code of the sensor; and a communication unit outside the wheel that receives the frame signal. In the wheel state detection device including:
Start command means for simultaneously transmitting start command signals to the plurality of wheel side communication units;
Receiving means for receiving frame signals transmitted from the plurality of wheel side communication units in response to the start command signal;
Standby command means for simultaneously transmitting standby command signals to the plurality of wheel side communication units when receiving the same number of identification codes as the number of sensors registered in advance;
A wheel state detection device further comprising:   The wheel state detection device according to claim 1, wherein the frame signal, the start command signal, and the standby command signal are all transmitted and received on the same channel.   3. The wheel state detection device according to claim 1, wherein the standby command means transmits the standby command signal when a predetermined time has elapsed since the start command signal was transmitted.   The wheel state detection device according to any one of claims 1 to 3, wherein a communication unit outside the wheel is provided in a vehicle body. A wheel provided with a sensor provided on each wheel, and a wheel side communication unit that transmits a frame signal including wheel state information detected by the sensor and an identification code of the sensor,
Receiving means for receiving an activation command signal transmitted from a communication unit outside the wheel;
Frame transmission means for transmitting the frame signal in response to the activation command signal;
In response to a standby command signal transmitted when the same number of identification codes as the number of sensors registered in advance are received in the communication unit outside the wheel, standby shift means for shifting to a reception standby state;
A wheel characterized by further comprising:   The wheel according to claim 5, wherein the frame signal, the start command signal, and the standby command signal are all transmitted and received on the same channel.   The wheel according to claim 5 or 6, wherein a communication unit outside the wheel is provided in a vehicle body. A vehicle body including a vehicle body side communication unit that receives a frame signal including wheel state information detected by a sensor provided on each wheel and an identification code of the sensor from a wheel side communication unit provided on the wheel side,
Start command means for simultaneously transmitting start command signals to a plurality of wheel side communication units;
Receiving means for receiving frame signals transmitted from the plurality of wheel side communication units in response to the start command signal;
Standby command means for simultaneously transmitting standby command signals to the plurality of wheel side communication units when receiving the same number of identification codes as the number of sensors registered in advance;
A vehicle body characterized by further comprising:   9. The vehicle body according to claim 8, wherein the frame signal, the start command signal, and the standby command signal are all transmitted and received through the same channel. The vehicle body according to claim 8 or 9, wherein the standby command means transmits the standby command signal when a predetermined time has elapsed since the start command signal was transmitted.

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