JP2012224230A - Tire position determination system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire position determination system that notifies a user of tire positions while reducing a calculation load on the vehicle.SOLUTION: The tire position determination system includes: a transmitter 7 which is provided at a position to have different distances to each of tires 2 provided in a vehicle 1, and starts each tire valve 3 by radio; a position detection request part 4b that transmits a position detection request signal Srq to each tire valve 3, the position detection request signal including at least a signal receiving intensity range indicating a signal receiving intensity of each tire valve 3 for receiving a radio wave transmitted from the transmitter 7; a signal intensity acquisition part 31b that acquires the signal receiving intensity when each tire valve 3 receives the position detection request signal Srq; a position determination part 31c that determines the tire position depending on the position of the signal receiving intensity acquired by the signal intensity acquisition part 31b in the receiving signal intensity range; and a position transmission part 31d that transmits a position signal Sp, including the determination result of the position determination part 31c, from each tire valve 3 to a vehicle body.

Description

  The present invention relates to a tire position determination system that determines the position of each tire.

  Conventionally, a tire pressure monitoring system (TPMS: Tire Pressure Monitoring System) is known as an apparatus mounted on a vehicle. The tire pressure monitoring system is a system for monitoring tire abnormality by acquiring tire pressure and temperature by wireless communication from a sensor mounted on a tire of a vehicle during traveling. The sensor is integrally mounted on the tire valve (see, for example, Patent Document 1).

  The tire valve of the tire pressure monitoring system as described above is provided with a transmitter that transmits detection information such as air pressure and temperature detected by a mounted sensor using a radio signal. In addition, the vehicle is provided with a receiver that can receive a wireless signal including detection information transmitted from the transmitter, and a control device that displays air pressure, temperature, and the like from the received signal and warns when there is an abnormality. Most transmitters are built in tire valves.

  In the tire pressure monitoring system, a radio signal including valve identification information (valve ID) is transmitted from a tire valve transmitter in order to determine whether the radio signal is transmitted from a tire valve corresponding to the host vehicle. . Then, the control device of the tire pressure monitoring system authenticates whether or not the valve ID is registered in advance, and on the condition that the authentication is established, the air pressure and temperature based on the detection information included in the radio signal. Is displayed, and a warning is given when an abnormality occurs.

JP 2003-335115 A

  By the way, in the tire pressure monitoring system, in order to authenticate the valve ID, the valve ID of the tire mounted on the host vehicle must be registered in the control device of the tire pressure monitoring system. Accordingly, tire pressure monitoring systems have been developed that transmit a valve ID from a tire and register the tire position based on the received signal strength of a radio signal including the valve ID. However, in recent years, calculation processing on the vehicle side has been enlarged due to integration of systems in an in-vehicle device provided in a vehicle, and it is also required to reduce calculation processing. Therefore, there is a demand for a tire position determination system that can grasp the tire position while suppressing the calculation load on the vehicle side.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a tire position determination system capable of grasping a tire position while suppressing a calculation load on the vehicle side.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 is a receiving means for receiving a radio signal including air pressure information of the tire in a vehicle body from a tire valve attached to a tire of the vehicle, and a control device for monitoring the air pressure received by the receiving means. In a tire position determination system for determining each position of the tire, the distance from each tire provided in the vehicle is provided at a different position, and the tire valve is wirelessly provided. A position detection request for transmitting to the tire valve request information including at least a reception signal intensity range indicating a startable transmission means and a reception signal intensity range at which each tire valve receives a radio wave from the transmission means. Means, and a received signal strength acquisition means for acquiring a received signal strength when the tire valve receives the request information; The tire position determination means for determining the tire position according to which of the reception signal intensity ranges the reception signal intensity acquired by the reception signal intensity acquisition means, and position information including the determination result of the tire position determination means, The gist of the invention is that it includes tire position transmitting means for transmitting from the tire valve to the vehicle body.

  According to the configuration, the request information including the reception signal strength range at each tire position is transmitted from the vehicle, and the tire valve that has received the request information based on the reception signal strength range determines the tire position by itself and determines the vehicle. Send location information including results. For this reason, since the tire valve determines the tire position only by transmitting the reception signal strength determined in advance depending on the tire position, the tire position can be grasped while suppressing the calculation load on the vehicle side.

  According to a second aspect of the present invention, in the tire position determination system according to the first aspect, when the vehicle body cannot correctly receive the position information, the position detection requesting unit narrows the received signal strength range and performs the request. The gist is to transmit the information to the tire valve again.

  The received signal strength is expected to deviate from the original value due to environmental influences and the position of the tire valve. Therefore, according to the same configuration, when a plurality of tire valves transmit the same tire position because the received signal strength deviates from the original value, the same received signal strength is reduced by narrowing the overlapping received signal strength range. It becomes possible to make one tire included in the range. Therefore, it is possible to accurately grasp the tire position.

  According to a third aspect of the present invention, in the tire position determination system according to the first or second aspect, the position information includes a valve ID for identifying the tire valve together with the tire position determined by the tire position determination means. The gist of the present invention is that the vehicle body includes tire position registration means for associating the tire position transmitted from the tire position transmission means with the valve ID and registering it in the control device.

  According to this configuration, the tire position and valve ID determined by the tire valve based on the received signal intensity range transmitted from the vehicle are registered in the vehicle. For this reason, it is possible to grasp the tire position from the valve ID included in the radio signal transmitted from the tire valve, and to monitor the air pressure and the like at each tire position.

  According to a fourth aspect of the present invention, in the tire position determination system according to the first or second aspect, a vehicle ID registration for registering a vehicle ID, which is a unique ID of the vehicle body, in each tire valve attached to each tire. And the position information is a signal including the vehicle ID registered in the tire valve together with the tire position determined by the tire position determination unit, and is a signal transmission source based on the vehicle ID. The gist of the present invention is that the vehicle body is provided with a tire position determination means for determining the tire position based on the tire position included in the position information.

  According to this configuration, the vehicle ID of the vehicle corresponding to the tire valve is registered, and when the air pressure information is requested, the tire position is determined by the tire valve based on the received signal strength range, and the tire position and the vehicle ID are determined. And air pressure information. For this reason, while confirming that it is a tire valve corresponding to the own vehicle by vehicle ID, it is possible to acquire the air pressure in each tire position.

  According to the present invention, in the tire position determination system, it is possible to grasp the tire position while suppressing the calculation load on the vehicle side.

The block diagram which shows schematic structure of a tire pressure monitoring system. (A) Schematic diagram showing contents of position detection request signal, (b) Schematic diagram showing contents of position signal, (c) Schematic diagram showing contents of detection signal. The figure which shows the received signal strength and the received signal strength range which change with the distance of a transmitter and a tire valve. The sequence chart which shows the tire position registration operation | movement in a tire pressure monitoring system. The sequence chart which shows the retry of the tire position registration operation | movement in a tire pressure monitoring system. The sequence chart which shows the acquisition operation | movement of the detection information in a tire pressure monitoring system. The sequence chart which shows the retry of acquisition operation | movement of the detection information in a tire pressure monitoring system.

(First embodiment)
A first embodiment in which the present invention is embodied in a tire pressure monitoring system will be described below with reference to FIGS. A vehicle is provided with a tire pressure monitoring system (TPMS: Tire Pressure Monitoring System) that detects tire pressure and the like and monitors abnormalities such as air pressure.

  As shown in FIG. 1, each tire 2 (a total of 4) of the vehicle 1 has an air inlet and tire valves 3 (a total of 4) that detect and transmit the air pressure of the tire 2. Is provided. The tire valve 3 is equipped with a valve control unit 31 that controls the operation of the tire valve 3. Connected to the valve control unit 31 is a UHF transmission unit 33 that transmits a detection signal Stp including the air pressure of the tire 2 by radio waves in a UHF (Ultra High Frequency) band. The valve control unit 31 is provided with a memory 31a that stores a valve ID.

  The tire valve 3 includes a pressure sensor 34 that detects the pressure of the tire 2, a temperature sensor 35 that detects the temperature of the tire 2, an acceleration sensor 36 that detects acceleration applied in the radial direction of the tire 2, and the like. . These sensors output detection signals to the valve control unit 31. The detection signal Stp transmitted by the UHF transmission unit 33 includes the air pressure and temperature of the tire 2, the unique ID (valve ID) of the tire 2, and the like. The tire valve 3 transmits a detection signal Stp from the UHF transmission unit 33 in order from each tire valve 3 when the acceleration sensor 36 detects acceleration. The UHF transmitter 33 functions as a transmission unit.

  A control device 4 for controlling the tire pressure monitoring system is mounted on the vehicle body of the vehicle 1. The control device 4 is connected to a receiver 5 that receives a detection signal Stp including the air pressure of the tire 2 transmitted from the tire valve 3 of each tire 2 by radio waves in the UHF band. The control device 4 is connected with a display device 6 for displaying the air pressure of the tire 2 to the driver. The display device 6 is installed in the driver's seat of the vehicle 1. The receiver 5 functions as a receiving unit.

  When receiving the detection signal Stp, the receiver 5 outputs the valve ID and the detection information included in the detection signal Stp to the control device 4. The control device 4 performs ID verification for determining whether or not the valve ID in the detection signal Stp matches the valve ID stored in the memory 4a. If the ID verification is established, the control device 4 is registered in the vehicle 1. It is recognized that the signal is from the tire 2. Then, the control device 4 reads the air pressure and temperature of the tire 2 included in the detection signal Stp and causes the display device 6 to display the air pressure and temperature of the tire 2. Further, if the air pressure or temperature of the tire 2 is abnormal, the control device 4 notifies that fact by the display device 6 or an alarm (not shown). The control device 4 repeatedly executes this operation every time it receives the detection signal Stp from the tire valve 3.

  The tire pressure monitoring system of the present embodiment is provided with a tire position determination system for determining the tire position in the vehicle 1 by causing the tire valve 3 to calculate the position of each tire valve 3 and returning it to the vehicle 1. . That is, the vehicle 1 is provided with a transmitter 7 that makes a tire position detection request to the tire valve 3. The transmitter 7 transmits a position detection request signal Srq to the tire valve 3 using radio waves in an LF (Low Frequency) band. In addition, the tire valve 3 is provided with an LF receiver 32 that receives LF band radio waves transmitted from the vehicle 1.

  The control device 4 of the vehicle 1 is provided with a position detection request unit 4b that causes the transmitter 7 to transmit a position detection request signal Srq that causes the tire valve 3 to detect the tire position. The position detection request unit 4b transmits a position detection request signal Srq from the transmitter 7 by LF radio waves when registering a valve ID such as a registration mode. The position detection request unit 4b functions as a position detection request unit. Further, the position detection request signal Srq corresponds to request information.

  As shown in FIG. 2A, the position detection request signal Srq includes a wake code that activates the tire valve 3, a bit that requests the tire valve 3 to start position determination, and which position of the tire valve 3 is used. A received signal strength range indicating whether or not the position detection request signal Srq is received at a certain received signal strength is included. The reception signal strength range includes a data group of a signal reception strength of the left front tire, a right front tire reception signal strength range, a left rear tire reception signal strength range, and a right rear tire reception signal strength range.

  As shown in FIG. 3, the received signal strength of the radio signal transmitted from the transmitter 7 received by each tire valve 3 at each tire position becomes higher as the distance from the transmitter 7 becomes shorter. The lower the distance from, the lower the value (L1 <L2 <L3 <L4). That is, the relationship of the received signal strength of each tire valve 3 is as follows: received signal strength V1 of the left front tire valve 3> received signal strength V2 of the right front tire valve 3> received signal strength V3 of the left rear tire valve 3> right rear The received signal intensity V4 of the tire valve 3 becomes. The reception signal strength ranges R1, R2, R3, and R4 are set in advance so as to include the reception signal strengths V1, V2, V3, and V4 of the respective tire valves 3. The reception signal strength ranges R1, R2, R3, and R4 set in this way are included in the position detection request signal Srq. The received signal strength range R1 is a range sandwiched between the upper limit threshold T1 and the lower limit threshold T2, and the received signal strength range R2 is a range sandwiched between the upper limit threshold T2 and the lower limit threshold T3, and the received signal strength range. R3 is a range sandwiched between the upper limit threshold T3 and the lower limit threshold T4, and the received signal strength range R4 is a range sandwiched between the upper limit threshold T4 and the lower limit threshold T5.

  As shown in FIG. 1, the LF receiver 32 of the tire valve 3 is provided with a received signal strength detection circuit (RSSI: Received Signal Strength Indicator) 32 a that detects the received signal strength of the received radio signal. When the RSSI 32 a receives the radio signal, the RSSI 32 a outputs the detection result to the valve control unit 31 when detecting the received signal strength.

  The valve control unit 31 is provided with a signal strength acquisition unit 31b that acquires the received signal strength detected by the RSSI 32a. When the signal strength acquisition unit 31b receives the position detection request signal Srq from the vehicle 1, the signal strength acquisition unit 31b acquires the received signal strength when the position detection request signal Srq is received from the RSSI 32a. The signal strength acquisition unit 31b functions as a received signal strength acquisition unit.

  Further, the valve control unit 31 is provided with a position determination unit 31c that determines the tire position using the received signal strength acquired by the signal strength acquisition unit 31b. The position determination unit 31c determines the tire position depending on which of the received signal strength ranges R1, R2, R3, and R4 included in the position detection request signal Srq the received signal strength acquired by the signal strength acquisition unit 31b. For example, as shown in FIG. 3, if the received signal strength is V1, the position determining unit 31c is included in the left front received signal strength range R1, and therefore determines that the tire position is front left. The position determination unit 31c functions as a tire position determination unit.

  Further, the valve control unit 31 is provided with a position transmission unit 31d that transmits a position signal Sp including the tire position determined by the position determination unit 31c to the vehicle 1. The position transmission unit 31d transmits a position signal Sp including the tire position and the valve ID from the UHF transmission unit 33. The position transmission unit 31d functions as a tire position transmission unit. Further, the position signal Sp corresponds to position information.

  As shown in FIG. 2 (b), the position signal Sp includes a bit for notifying that the own signal is the position signal Sp, a tire position determined by the position determination unit 31c, a valve ID for identifying the tire valve 3, including. The position signal Sp has the same signal format (frequency, signal frame, bit rate, etc.) as the detection signal Stp.

  As shown in FIG. 1, the control device 4 of the vehicle 1 determines the tire position of each tire valve 3 by checking the tire position and valve ID included in the position signal Sp transmitted from each tire valve 3. A position determination unit 4c is provided. The position determination unit 4c determines whether or not one tire valve 3 is positioned for each tire position, and determines the tire position. In addition, the position determination part 4c functions as a tire position determination means.

  Further, the control device 4 is provided with a position registration unit 4d that registers each tire valve 3 based on the tire position and the valve ID included in the position signal Sp transmitted from each tire valve 3. The position registration unit 4d registers each tire valve 3 in the memory 4a in association with each valve ID and the tire position based on the determination result of the position determination unit 4c. The position registration unit 4d functions as a tire position registration unit.

  Here, since the position of the tire valve 3 slightly changes due to the rotation of the tire 2, it is also conceivable that the received signal intensity changes. As shown in FIG. 3, for example, the reception signal strength V2 (shown as V2 ′) of the right front tire valve 3 that is originally included in the right front reception signal strength range R2 is included in the left front reception signal strength range R1. is there. That is, two received signal strengths V1 and V2 ′ are included in the left front received signal strength range R1. In such a case, the position determination units 31c of the two tire valves 3 determine the tire position as front left based on the received signal strength. Then, a position signal Sp including the front left tire position is transmitted from the two tire valves 3.

  As shown in FIG. 1, when the position determination unit 4c receives the position signal Sp transmitted from each tire valve 3, the tire position overlaps, so the valve ID and the tire position cannot be associated with each other. The position cannot be determined. In such a case, the position detection requesting unit 4b narrows the received signal strength range where the tire positions overlap to set the received signal strength narrow range, and transmits the position detection request signal Srq including the received signal strength narrow range to the transmitter. 7 to send again. That is, as shown in FIG. 3, the position detection requesting unit 4b, for example, when the left reception signal strength range R1 includes two reception signal strengths V1 and V2 ', the left front reception signal strength range R1. By increasing the lower limit threshold T2, the left front reception signal strength range R1 is narrowed, and the left front reception signal strength narrow range R1 ′ is set. Note that the upper right threshold value T2 of the right front received signal strength range R2 increases, and therefore the range becomes larger.

  As shown in FIG. 1, when the tire valve 3 receives the position detection request signal Srq transmitted from the vehicle 1, the tire valve 3 detects the received signal intensity, determines the tire position, and transmits the position signal Sp including the tire position. To do. At this time, since the left front received signal strength range R1 ′ is narrowed from the left front received signal strength range R1, overlapping of tire positions is eliminated. Therefore, the vehicle 1 can register the tire position by transmitting the position signal Sp including the different tire position from each tire valve 3. When the position detection requesting unit 4b of the vehicle 1 can register the tire position within the changed received signal intensity range, the position detection requesting part 4b registers the received signal intensity narrow range in the memory 4a and uses it for subsequent position specification.

Next, the registration operation of the tire pressure monitoring system of this example will be described with reference to FIGS.
As shown in FIG. 4, for example, when the vehicle 1 is set to the registration mode, the vehicle 1 transmits a position detection request signal Srq to register the tire position of each tire valve 3 (step S <b> 1). That is, the position detection request unit 4b causes the transmitter 7 to transmit a position detection request signal Srq including the received signal intensity range at each tire position.

  When the tire valve 3 receives the position detection request signal Srq, the tire valve 3 detects the received signal strength (step S2). That is, when receiving the position detection request signal Srq from the vehicle 1, the signal strength acquisition unit 31b acquires the received signal strength of the position detection request signal Srq detected by the RSSI 32a. Subsequently, the tire valve 3 determines the tire position based on the acquired received signal strength (step S3). That is, the position determination unit 31c determines the tire position depending on whether the received signal strength acquired by the signal strength acquisition unit 31b is included in any of the received signal strength ranges R1, R2, R3, and R4 included in the position detection request signal Srq. To do. The tire valve 3 transmits a position signal Sp including the determined tire position (step S4). That is, the position transmission unit 31d causes the UHF transmission unit 33 to transmit the position signal Sp including the tire position and the valve ID obtained from the received signal strength.

  When the vehicle 1 receives the position signal Sp transmitted from each tire valve 3, the vehicle 1 checks the tire position and valve ID included in each position signal Sp (step S5). That is, the position determination part 4c confirms whether one valve ID exists with respect to each tire position. When the vehicle 1 can confirm all the tire positions, the vehicle 1 registers the tire position and the valve ID in association with each other (step S6). That is, the position registration unit 4d registers each tire valve 3 in the memory 4a in association with each valve ID and the tire position.

  As shown in FIG. 5, when a plurality of valve IDs exist for one tire position in step S5, the vehicle 1 does not register the tire position and makes a tire position detection request again. Do (retry).

  When the tire position detection request is retried, the vehicle 1 sets a reception signal intensity narrow range in which the reception signal intensity ranges of the overlapping tire positions are narrowed (step S10). That is, for example, when the two reception signal strengths V1 and V2 ′ are included in the left front reception signal strength range R1, the position detection request unit 4b increases the lower limit threshold of the left front reception signal strength range R1. Then, a reception signal intensity narrow range R1 ′ on the left front side in which the reception signal intensity range is narrowed is set.

  Subsequently, the vehicle 1 transmits a position detection request signal Srq in order to register the tire position of each tire valve 3 (step S11). That is, the position detection request unit 4b causes the transmitter 7 to transmit a position detection request signal Srq that includes a received signal intensity narrow range at each tire position.

  When the tire valve 3 receives the position detection request signal Srq, the tire valve 3 detects the received signal strength (step S12), and determines the tire position based on the acquired received signal strength (step S13). The tire valve 3 transmits a position signal Sp including the determined tire position (step S14).

  When the vehicle 1 receives the position signal Sp transmitted from each tire valve 3, the vehicle 1 confirms the tire position and valve ID included in each position signal Sp (step S15), and can confirm all tire positions. In this case, the tire position and the valve ID are associated and registered (step S16). When the tire position can be registered, the vehicle 1 registers the received signal intensity narrow range (step S17). That is, the position detection request unit 4b registers the changed received signal intensity narrow range in the memory 4a.

  When the valve ID of each tire valve 3 is registered in the vehicle 1, the tire pressure monitoring system receives the detection signal Stp transmitted from the tire valve 3 by the receiver 5 and confirms each tire position from the valve ID. The air pressure information of each tire 2 can be displayed on the display device 6.

  In the tire pressure monitoring system according to the present embodiment, when registering the valve ID of the tire valve 3 in the vehicle 1, the position detection request signal Srq including the received signal strength range for determining the tire position from the vehicle 1 is included. Send. In the tire pressure monitoring system, each tire valve 3 determines the tire position based on the received signal strength detected by the position detection request signal Srq, and transmits a position signal Sp including the tire position to the vehicle 1. That is, since the tire position determination calculation in the registration of the valve ID to the vehicle 1 is performed on the tire valve 3 side, the tire position can be grasped while suppressing the calculation load on the vehicle 1 side.

  In addition, when the tire positions transmitted from the tire valve 3 are overlapped, the tire position is more accurately determined by causing the tire valve 3 to determine again the tire position based on the received signal intensity narrow range obtained by narrowing the received signal intensity range. I can grasp it.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) The position detection request signal Srq including the reception signal intensity range at each tire position is transmitted from the vehicle 1, and the tire valve 3 that has received the position detection request signal Srq based on this reception signal intensity range determines the tire position by itself. Then, the tire position is transmitted to the vehicle 1. For this reason, the tire valve 3 determines the tire position only by transmitting the reception signal strength determined in advance depending on the tire position, so that the tire position can be grasped while suppressing the calculation load on the vehicle 1 side. .

  (2) The reception signal strength is expected to deviate from the original value due to environmental influences and the position of the tire valve 3, and the tire valve 3 has transmitted the same tire position due to the reception signal strength deviating from the original value. In some cases, the tires 2 included in the same received signal strength range can be made one by narrowing the overlapping received signal strength ranges. Therefore, the tire position can be accurately grasped.

  (3) The tire position and valve ID determined by the tire valve 3 based on the received signal intensity range transmitted from the vehicle 1 are registered in the vehicle 1. For this reason, the tire position can be grasped by the valve ID included in the position detection request signal Srq transmitted from the tire valve 3, and the air pressure of each tire 2 can be monitored.

(4) Since the narrowed received signal strength range is stored on the vehicle side and can be used at the time of subsequent position specification, communication can be made efficient. Thus, the number of communications can be reduced.
(Second Embodiment)
Hereinafter, a second embodiment in which the present invention is embodied in a tire pressure monitoring system will be described with reference to FIGS. 6 and 7. In the tire pressure monitoring system of this embodiment, a position detection request signal Srq is transmitted from the vehicle 1 as a request signal of the detection signal Stp, a vehicle ID is registered in the tire valve 3, and a tire position and a vehicle are included in the detection signal Stp. The point including the ID is different from the first embodiment. Hereinafter, a description will be given focusing on differences from the first embodiment. Note that the tire pressure monitoring system of this embodiment has substantially the same configuration as the tire pressure monitoring system of the first embodiment shown in FIG.

As shown in FIG. 1, a vehicle ID unique to the vehicle is registered in the vehicle 1. That is, a vehicle ID for identifying the vehicle 1 is registered in the memory 4 a of the control device 4.
Further, the vehicle ID of the vehicle 1 to which the tire 2 is attached is also registered in the tire valve 3. That is, the valve control unit 31 is provided with a vehicle ID registration unit 31e that registers a vehicle ID in the memory 31a. The vehicle ID registration unit 31e acquires a vehicle ID and registers it in the memory 31a when the vehicle ID is included in a wireless signal transmitted from a registration tool (not shown) or the like. The vehicle ID registration unit 31e functions as a vehicle ID registration unit.

  The vehicle 1 transmits a position detection request signal Srq to the tire valve 3 when it is desired to acquire detection information such as the air pressure of the tire 2. When the tire valve 3 receives the position detection request signal Srq, the tire valve 3 detects the received signal intensity and determines the tire position, as in the first embodiment. Then, the tire valve 3 transmits a detection signal Stp including the determined tire position, a vehicle ID registered in advance, and detection information of the tire 2.

Next, the detection information acquisition operation by the tire pressure monitoring system of this embodiment will be described with reference to FIGS.
As shown in FIG. 6, during traveling, the vehicle 1 transmits a position detection request signal Srq to cause each tire valve 3 to transmit detection information (step S21). That is, the position detection request unit 4b causes the transmitter 7 to transmit a position detection request signal Srq including the received signal intensity range at each tire position.

  As in the first embodiment, the tire valve 3 detects the received signal strength (step S22), and determines the tire position based on the detected received signal strength (step S23). Then, the tire valve 3 transmits a detection signal Stp including detection information such as the determined tire position, vehicle ID, and air pressure (step S24). That is, the position transmission unit 31d causes the UHF transmission unit 33 to transmit the detection signal Stp including the tire position obtained from the received signal strength, the vehicle ID registered in the memory 31a, and detection information such as air pressure.

  When the vehicle 1 receives the detection signal Stp transmitted from each tire valve 3, the vehicle 1 confirms the tire position and vehicle ID included in each detection signal Stp (step S25). That is, the position determination part 4c confirms whether one valve ID exists with respect to each tire position. When the vehicle 1 can confirm the positions of all the tires, the vehicle 1 displays the detection information of each tire 2 on the display device 6 (step S26).

  As shown in FIG. 7, when there are a plurality of valve IDs for one tire position in step S25, the vehicle 1 detects the detection information of the tire 2 as in the first embodiment. The display information is not displayed and the detection information request for the tire 2 is requested again (retry).

  When the request for the detection information of the tire 2 is retried, the vehicle 1 sets a reception signal intensity narrow range that narrows the reception signal intensity range of the overlapping tire position (step S30), and sets the tire position of each tire valve 3. In order to register, a position detection request signal Srq is transmitted (step S31).

  The tire valve 3 detects the received signal strength (step S32), and determines the tire position based on the acquired received signal strength (step S33). The tire valve 3 transmits a detection signal Stp including the determined tire position, vehicle ID, and detection information (step S34).

  When the vehicle 1 receives the detection signal Stp transmitted from each tire valve 3, the vehicle 1 can confirm the tire position and valve ID included in each detection signal Stp (step S35), and can confirm all tire positions. In that case, the detection information of each tire 2 is displayed on the display device 6 (step S36). Then, when the detection information of each tire 2 can be displayed on the display device 6, the vehicle 1 registers the received signal intensity narrow range (step S37).

  In the tire pressure monitoring system according to the present embodiment, the vehicle ID corresponding to the vehicle 1 is registered by registering the vehicle ID unique to the tire valve 3 without registering the valve ID of the tire valve 3 in the vehicle 1. Can be recognized. Moreover, the vehicle 1 can acquire the detection information of each tire 2 by including the tire position together with the detection information of the tire 2. That is, it is possible to grasp the tire position and the state of the tire 2 without registering the valve ID in the vehicle 1.

As described above, according to the embodiment described above, in addition to the effects (1), (2) and (4) of the first embodiment, the following effects can be obtained.
(5) When the vehicle ID of the vehicle 1 corresponding to the tire valve 3 is registered and the air pressure information is requested, the tire position is determined by the tire valve 3 based on the received signal intensity range. And air pressure information. For this reason, while confirming that it is the tire valve 3 corresponding to the own vehicle 1 by vehicle ID, the air pressure in each tire position can be acquired.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, when the received signal strength range is narrowed, the lower limit threshold value of the overlapping received signal strength range is increased, but the upper limit threshold value of the overlapping received signal strength range may be decreased.

In the above embodiment, when the same tire position exists, the received signal strength range is narrowed, but retry may be performed using the same received signal strength range.
In the above embodiment, the sensors mounted on the tire valve 3 are not limited to those described in the embodiment, and may be appropriately changed or added.

  In the first embodiment, the tire valve 3 is not limited to the one that transmits the detection signal Stp when the acceleration sensor 36 detects the rotation of the tire 2. For example, the tire valve 3 may constantly transmit the detection signal Stp.

  In the above embodiment, the radio signal is transmitted from the tire valve 3 using radio waves in the UHF band, but other frequency bands such as the LF band and the HF (High Frequency) band may be used instead of the UHF band.

In the first embodiment, an initiator type in which the tire valve 3 is activated by the activation signal from the initiator and transmits the detection signal Stp may be employed.
In the above embodiment, the request information is not limited to the position detection request signal Srq that functions as a trigger signal for the tire valve 3, but may be other signals. For example, a dedicated radio signal sent separately after the trigger signal may be used.

  In the above embodiment, the position information is not limited to the position signal Sp and the detection signal Stp in the embodiment, and may be any information that can determine the tire position. For example, the position signal Sp may also serve as tire air pressure information, and the detection signal Stp may be a dedicated signal for notifying a position determination result. Further, it may be a signal issued only for notifying the confirmation result of the received signal strength range.

  In the second embodiment, the vehicle ID may be wirelessly transmitted from the transmitter 7 to the tire valve 3 automatically and registered in the tire valve 3. The position detection request signal Srq may be transmitted with the vehicle ID included.

In the above embodiment, the transmission means is not limited to the transmitter 7 installed on the vehicle body, and may be a dedicated tool outside the vehicle, for example.
Next, a technical idea that can be grasped from the above embodiment will be described together with its effects.

  (A) The tire position determination system according to claim 2, wherein the reception signal intensity range is narrowed by increasing a lower threshold of the reception signal intensity ranges of overlapping tire positions. .

  According to this configuration, the received signal strength range is narrowed by increasing the lower threshold of the received signal strength range of overlapping tire positions, so that a new received signal strength range can be set without performing complicated arithmetic processing. it can.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Tire, 3 ... Tire valve, 4 ... Control apparatus, 4a ... Memory, 4b ... Position detection request part as position detection request means, 4c ... Position determination part as tire position determination means, 4d ... Tire Position registration unit as position registration means, 5 ... Receiver as reception means, 6 ... Display device, 7 ... Transmitter as transmission means, 31 ... Valve control section, 31a ... Memory, 31b ... Tire position determination means Position determination unit, 31c ... Signal intensity acquisition unit as reception signal strength acquisition unit, 31d ... Position transmission unit as tire position transmission unit, 32 ... LF reception unit, 32a ... RSSI (reception signal strength detection circuit), 33 ... UHF Transmitting unit, 34 ... pressure sensor, 35 ... temperature sensor, 36 ... acceleration sensor, R1, R1 ', R2, R3, R4 ... received signal intensity range, Sp ... position signal, Srq ... position Output request signal, Stp ... detection signal, V1, V2, V2', V3, V4 ... received signal strength.

Claims (4)

Used in a tire pressure monitoring system comprising a receiving means for receiving a radio signal including air pressure information of the tire from a tire valve attached to a vehicle tire and a control device for monitoring the air pressure received by the receiving means. In the tire position determination system for determining each position of the tire,
Transmission means provided at different positions from each tire provided in the vehicle, and capable of starting the tire valve wirelessly;
Position detection requesting means for transmitting to the tire valve request information including at least a received signal strength range indicating how much received signal strength each radio wave from the transmitting means is received by each tire valve;
Received signal strength acquisition means for acquiring received signal strength when the tire valve receives the request information;
Tire position determination means for determining a tire position according to which of the reception signal intensity ranges the reception signal intensity acquired by the reception signal intensity acquisition means;
A tire position determination system comprising: tire position transmission means for transmitting position information including a determination result of the tire position determination means from the tire valve to the vehicle body. In the tire position determination system according to claim 1,
When the vehicle body cannot correctly receive the position information, the position detection request unit narrows the reception signal intensity range and transmits the request information to the tire valve again. In the tire position determination system according to claim 1 or 2,
The position information is a signal including a valve ID for identifying the tire valve together with the tire position determined by the tire position determination means,
A tire position determination system comprising tire position registration means for associating and registering the tire position transmitted from the tire position transmission means with the valve ID in the control device. In the tire position determination system according to claim 1 or 2,
The tire valve is provided with vehicle ID registration means for registering a vehicle ID, which is a unique ID of the vehicle body, in each tire valve attached to each tire,
The position information is a signal including the vehicle ID registered in the tire valve together with the tire position determined by the tire position determination means,
The vehicle body includes tire position determination means that confirms the legitimacy of the tire valve that is the signal transmission source based on the vehicle ID and that determines the tire position based on the tire position included in the position information. Tire position determination system.

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