JP2006015895A - Tire pressure monitoring device - Google Patents

Abstract

A tire pressure monitoring device capable of registering a tire identification code without erroneously registering radio waves from an adjacent vehicle.
SOLUTION: Tire pressure sensors A, B, C, D attached to tires 1, 2, 3, 4 respectively, a receiver attached to a vehicle side, tire identification code registration means for registering an ID In the tire pressure monitoring device equipped with, the receiver is a tuner with antennas (1), (2), (3), (4) set in the vicinity of each of a plurality of tires by the number of tires, When the tire identification code registration means receives the radio wave transmitted from the transmitter of one tire pressure sensor by the tuner with each antenna, the received radio wave intensity is read at least twice at different times from one frame of the transmission signal, Only when the relationship between the received radio wave intensities read at these different times is similar to each other, it is determined as an ID registration candidate.
[Selection] Figure 1

Description

  The present invention belongs to a technical field of a tire pressure monitoring device that determines a mounting position of each tire and individually registers a tire identification code (ID) corresponding to the tire mounting position.

Conventionally, the automatic ID registration logic of a tire pressure monitoring device with a receiving antenna or tuner at each wheel position temporarily stores the reception sensitivity received by each receiver of the vehicle when performing automatic ID registration. Is registered as a candidate for an ID selected by the tuner (see, for example, Patent Document 1).
JP 2003-118333 A

  However, in the conventional tire pressure monitoring device, when the radio wave transmitted from the transmitter of the adjacent vehicle running along with the own vehicle is received by the receiver of the own vehicle, the radio wave transmitted from the transmitter of the adjacent vehicle. When the strength is higher than the strength of the radio wave transmitted from the transmitter of the own vehicle, there is a problem that the tire ID is erroneously registered in the own vehicle.

  The present invention has been made paying attention to the above-mentioned problem. Even if high radio wave intensity enters the receiver of the own vehicle, the buffer capacity for temporarily storing the tire identification code registration candidates is reduced. It is an object of the present invention to provide a tire pressure monitoring device capable of discriminating whether a vehicle is from a transmitter of a car or a transmitter of another vehicle and registering a correct tire identification code without erroneous registration.

In order to achieve the above object, according to the present invention, a pressure sensor that is attached to each of a plurality of tires mounted on a vehicle and detects each tire pressure, and at least the detected tire pressure is wirelessly transmitted together with a tire identification code for each tire. A tire pressure detecting means having a transmitter for transmitting a signal; a receiver mounted on the vehicle side for receiving a radio signal transmitted from the tire pressure detecting means; and a tire identification code of each tire In a tire pressure monitoring device provided with a tire identification code registration means for registering by memory update,
The receiver is set in the vicinity of each of a plurality of tires by the number of tires,
The tire identification code registration means reads at least two received radio wave intensities from one frame of the transmission signal at different times when each radio wave transmitted from the transmitter of one tire pressure detection means is received by each receiver. Only when the relationship between the received radio wave intensities read at these different times is similar to each other, the tire identification code is a registration candidate.

In the tire pressure monitoring device of the present invention, the number of tire-side receivers is set in the vicinity of each of the plurality of tires. Therefore, a high radio wave intensity may instantaneously enter the receiver of the own vehicle from the tire of the vehicle running adjacently. On the other hand, only when the relationship of the received radio wave intensity read from one frame at these different times is similar to each other, if it is a candidate for registration of a tire identification code and instantaneous high radio wave intensity enters from an adjacent vehicle The tire identification code is excluded from registration candidates.
As a result, the buffer capacity for temporarily storing the tire identification code registration candidates as compared with the case of registering the tire identification code with the highest radio wave intensity while temporarily storing the tire identification code registration candidates as in the prior art Even if high signal intensity enters the receiver of the vehicle, it is determined whether it is from the transmitter of the own vehicle or from the transmitter of another vehicle, and an accurate tire identification code without erroneous registration Registration can be carried out.

  Hereinafter, the best mode for carrying out the tire pressure monitoring apparatus of the present invention will be described based on Example 1 shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall view showing a vehicle to which the tire pressure monitoring device of the first embodiment is applied. As shown in FIG. 1, a left front wheel tire 1, a right front wheel tire 2, a left rear wheel tire 3, and a right Rear wheel tire 4, tire pressure sensors A, B, C, D (tire pressure detection means), tuner with antenna (1), (2), (3), (4) (receiver), tire pressure An alarm controller 5, a display 6, and a low air pressure warning lamp 7 are provided.

  The tire pressure sensors A, B, C, and D are respectively attached to the load valve positions of the road wheels of the tires 1, 2, 3, and 4 of the front and rear wheels, and detect the tire pressure of each tire individually. The ID (tire identification code) for each tire, detected pressure data (tire pressure information), and the like are transmitted to the tuners (1), (2), (3), (4) with antennas by radio signals.

  The antenna-equipped tuners (1), (2), (3), and (4) receive information transmitted from the tire pressure sensors A, B, C, and D and input them to the tire pressure alarm controller 5.

  The tire pressure alarm controller 5 performs ID registration for each tire, displays tire pressure information of the respective tires 1, 2, 3, and 4 of the front and rear wheels specified by the ID registration on the display 6, and front and rear wheels. When it is determined that at least one of the tire air pressures of the tires 1, 2, 3 and 4 has decreased, a lamp lighting command is output to the air pressure decrease warning lamp 6.

  FIG. 2 is a detailed view showing the tire pressure monitoring device of the first embodiment. The tire pressure sensors A, B, C, and D are a pressure sensor 10a (pressure sensor) that detects tire pressure and open (OFF) in a region where the acting centrifugal force is small, and close (ON) in a region where the centrifugal force is large. The centrifugal force switch 10b, the ASIC 10c that is an application specific integrated circuit, the transmitter 10d, and the transmission antenna 10e (transmitter) are respectively configured. Then, with the opening / closing of the centrifugal force switch 10b installed to ensure the battery life as a trigger, a long transmission interval (for example, 1 hour) in a region where the vehicle speed including stop is low, and a short in a region where the vehicle speed is higher than that, The transmission cycle is changed into two stages such as a transmission interval (for example, 1 minute).

  As shown in FIG. 2, the tuners with antennas (1), (2), (3), and (4) include a receiving antenna 11a that receives transmission data from the tire pressure sensors A, B, C, and D. And a tuner 11b which is a receiving circuit. Note that one-time transmission data from the tire pressure sensors A, B, C, and D includes information such as a start bit, function code, ID, pressure data, and checksum.

  As shown in FIG. 2, the tire pressure alarm controller 5 receives a 5V power supply circuit 5a, data received from the tuners 11b, performs various information processing, and performs ID registration. EEPROM 5c which is a read-only memory capable of electrically erasing stored information, and a display drive circuit for outputting a display drive command for displaying tire air pressure information of each tire 1, 2, 3, 4 to display 6 based on received data 5d, a warning lamp output circuit 5e for judging the pressure value of the mounted tire in the received data and outputting a tire air pressure warning command to the air pressure lowering warning lamp 7 when the pressure drops, and temporarily storing the ID registration processing information in the buffer And a RAM (random access memory) 5f to be stored.

  Next, the operation will be described.

  [Automatic ID registration process]

  FIG. 3 is a flowchart showing the flow of the automatic ID registration process for each tire executed by the tire pressure alarm controller 5 of the first embodiment. Each step will be described below (tire identification code registration means).

  In step S1, it is determined whether or not the ignition switch is on. If YES, the process proceeds to step S2, and if NO, the determination in step S1 is repeated.

  In step S2, based on the determination that the ignition switch is on in step S1, it is determined whether or not the vehicle speed V exceeds 30 km / h. If Yes, the process proceeds to step S3. If No, step S5 is performed. Proceed to This determination of the vehicle speed is because the centrifugal force switch 10b is surely turned on and the automatic ID registration mode is entered with a vehicle speed that can be transmitted at a short time interval (eg, 1 minute) as a start trigger.

  Based on the determination that the vehicle speed V in step S2 exceeds 30 km / h, in step S3, the failure diagnosis timer t is started, and in the next step S4, the automatic ID registration timer T is started, and step S5 Proceed to

  In step S5, the presence / absence of data of the ID stored last time is determined. If ID data is present, the process proceeds to step S8 to step S11, and the tuners with antennas (1), (2), (3), (4 ) For each of ID = A, B, C, and D stored in advance, the data is preferentially determined, and then the voltage drop alarm and puncture alarm processing from step S12 is performed. If there is no ID data, the process proceeds to step S6. In step S6, it is determined whether or not the failure diagnosis timer t has passed 600 s (= 600 seconds). If yes, the process proceeds to step S7 and there is no valid data. An alarm is issued, and in the case of No, automatic ID registration processing after step S20 is performed.

  In step S8 to step S11, after data is preferentially determined for ID = A, B, C, and D, in step S12, it is determined whether or not a voltage drop flag is set, and the voltage drop flag is set. If YES in step S13, the count number N is incremented by N = N + 1. In the next step S14, it is determined whether the count number N is N ≦ 10. If N> 10, the process proceeds to step S15. An alarm indicating a voltage drop is issued, and the process returns to step S1.

  On the other hand, if the voltage drop flag is not raised in the determination in step S12, or if the count number N is N ≦ 10 in the determination in step S14, the process proceeds to step S16, and the tire pressure data by the pressure sensor 10a is obtained. It is determined whether the tire pressure data is equal to or less than the puncture warning threshold value. If the tire pressure data is equal to or less than the puncture warning threshold value, the process proceeds to step S17 to count up the number of valid frames and the number of receptions. Whether or not the number of receptions is two or more is determined as described above, and if the condition of step S18 is satisfied, the process proceeds to step S19, where a puncture warning (however, the tire position display is not possible) is issued, and step S1. Return to.

  If it is determined in step S6 that the failure diagnosis timer t has not passed 600 s, or if it is determined in step S16 that the pressure data exceeds the puncture threshold, or if the number of valid frames is 4 or more in step S18, In addition, if it is determined that the number of receptions is not two or more, or if it is determined in step S45 that the automatic ID registration timer T has not passed 7 minutes, the automatic processing after step S20 is performed. The ID registration process is started.

  In step S20, the maximum value of the first RSSI value (1) (RSSI value = radio wave intensity value) measured by the tuners with antennas (1), (2), (3), (4) is the first setting. It is determined whether or not the value is greater than or equal to the value AmV. If Yes, the process proceeds to step S22. If No, the process proceeds to step S21 to invalidate the data as a new ID candidate, and the received data is discarded.

  In step S22, the maximum value (= first value) of the first RSSI value (1) measured by the tuners with antennas (1), (2), (3), (4) and the second value are calculated. It is determined whether or not the difference is equal to or larger than the second set value BmV. If Yes, the process proceeds to step S24. If No, the process proceeds to step S23, where the data as a new ID candidate is invalidated, and the received data is discarded.

  In step S24, the ID and RSSI value satisfying the conditions of step S20 and step S22 are held in the buffer 1 of the RAM 5f, and the process proceeds to step S25.

  In step S25, it is determined whether the maximum value of the last RSSI value (2) measured by the tuners with antennas (1), (2), (3), (4) is greater than or equal to the third set value CmV. If Yes, the process proceeds to step S27. If No, the process proceeds to step S26 to invalidate the data as a new ID candidate, and the received data is discarded from the buffer 1.

  In step S27, the maximum value (= first value) of the last RSSI value (2) measured by the tuners with antennas (1), (2), (3), (4) and the second value are calculated. It is determined whether or not the difference is equal to or greater than the fourth set value DmV. If Yes, the process proceeds to step S29. If No, the process proceeds to step S28, the data as the new ID is invalidated, and the received data is discarded from the buffer 1. The

  In step S29, the ID and RSSI value satisfying the conditions of step S25 and step S27 are moved from buffer 1 to buffer 2 of RAM 5f and held, and the process proceeds to step S30.

  In step S30, it is determined whether or not the ID moved to the buffer 2 in step S29 is the same as the previously stored ID. If Yes, the process proceeds to step S31, and if No, the process proceeds to step S36.

  If the ID moved to the buffer 2 in the determination in step S30 is the same as the previously stored ID, the process proceeds to step S31, where it is determined whether the tire pressure data by the pressure sensor 10a is equal to or less than the puncture alarm threshold; If the tire pressure data is less than or equal to the puncture warning threshold, the process proceeds to step S32 to count up the number of valid frames and the number of receptions. In the next step S33, the number of valid frames is four or more and the number of receptions is two or more. If the condition of step S33 is satisfied, the process proceeds to step S34, a puncture warning (tire position display is possible) is issued, and the process returns to step S1. If it is determined in step S31 that the tire air pressure data exceeds the puncture warning threshold value, the process proceeds to step S35, the data is retained, and the process returns to step S1.

  In step S36, it is determined whether or not a new ID is stored in the buffer 2 of each of the tuners with antennas (1), (2), (3), (4). In the case of, return to Step S1.

  In step S37, the previously stored four IDs are set as one set, and it is determined whether or not the ID set in the buffer 2 matches the previous one. If No, the process proceeds to step S39, and if Yes, Proceeding to step S38, it is determined that the four-wheel rotation has been performed, ID registration is executed, and the process proceeds to step S43.

  In step S39, the previously stored four IDs are set as one set, and it is determined whether or not the ID set in the buffer 2 matches the previously stored three IDs. If No, the process proceeds to step S41. If Yes, the process proceeds to step S40, it is determined that the three-wheel rotation has been performed, ID registration is executed, and the process proceeds to step S43.

  In step S41, the previously stored four IDs are set as one set, and it is determined whether or not the ID set in the buffer 2 matches the two stored last time. If No, the process proceeds to step S45. In the case of Yes, the process proceeds to step S42, it is determined that the two-wheel rotation is performed, ID registration is executed, and the process proceeds to step S43.

  In step S43, it is determined whether or not the corresponding wheel determined to have been rotated is an ID registered wheel. If the wheel is an ID registered, the process proceeds to step S48. If the wheel is other than an ID registered, the process proceeds to step S44. Proceed to continue automatic ID registration and proceed to step S45.

  In step S45, if it is determined in steps S37 to S41 that there is no four-wheel rotation, three-wheel rotation, or two-wheel rotation, or the wheel whose ID is registered based on the rotation determination in steps S43 to S44 is other than ID registration. If the automatic ID registration is ongoing, it is determined whether or not the automatic ID registration timer T has passed 7 minutes. If Yes, the process proceeds to step S46, and if No, the process returns to step S20.

  In step S46, based on the determination that the automatic ID registration timer T has passed 7 minutes in step S45, the ID in the buffer 2 of the corresponding tuner with the antenna is compared with the average RSSI value (frame average). Then, the process proceeds to step S47, where a new ID having the maximum RSSI average value is registered, and the process proceeds to step S48.

  In step S48, if it is determined in step S43 that the corresponding wheel is an ID registered wheel, or if a new ID is registered in step S47, the newly stored ID is received as data valid, and the process proceeds to step S49. Then, it is determined whether or not the tire pressure data by the pressure sensor 10a is equal to or less than the puncture alarm threshold value. If the tire pressure data is equal to or less than the puncture alarm threshold value, the process proceeds to step S51 to count up the number of effective frames and the number of receptions. In step S52, it is determined whether the number of valid frames is 4 or more and the number of receptions is 2 or more. If the condition of step S52 is satisfied, the process proceeds to step S53, and a puncture warning (tire position display is possible) is issued. It is. If it is determined in step S49 that the tire air pressure data exceeds the puncture warning threshold, the process proceeds to step S50 and is held as the latest data.

[Received data example]
For example, when a radio wave is transmitted from the transmitter of the tire pressure sensor A set on the left front wheel of the host vehicle while traveling at a vehicle speed of 50 km / h, FIG. 5 shows one transmission (= 5 frames) at 500 ms. Fig. 6 shows an example of data, and Fig. 6 shows one frame data example of the transmitter, reception strength (= radio wave strength) characteristics and tuner reading position (RSSI (1) and RSSI (2)) in the tuner with antenna. FIG.
Here, when the transmission data from the transmitter of the tire pressure sensor A is received by the tuner with the antenna, the position of the tuner with the antenna is influenced by the mounting position of the vehicle body, and the radio wave intensity is apparent from the broken line in FIG. There is a characteristic that the level changes. In Fig. 6, the first RSSI value (1) measured by the tuner with antenna and the last RSSI value (2) measured by the tuner with antenna are about 15ms that move by transmitting one frame data at a vehicle speed of 50km / h. Data at a position with a time difference of.

  FIG. 7 is a radar chart showing the radio wave intensity level (reception intensity level) received by the tuners with antennas (1) and (4) when the tire is rotated once. In FIG. 7, the first RSSI value (1) measured by the tuners with antennas (1) and (4) and the last RSSI value (2) measured by the tuners with antennas (1) and (4) are: The data is at a position where there is an angle difference (about 35 °) that fluctuates when one frame data is transmitted at a vehicle speed of 50 km / h.

[Automatic ID registration function]
For example, when traveling at 30 km / h or higher, in the flowchart of FIG. 3, the process proceeds from step S 1 → step S 2 → step S 3 → step S 4, and in step S 4, the automatic ID registration timer T starts. In this automatic ID registration mode, since the centrifugal force switch 10b of the transmitter is surely turned on and the vehicle speed that can be transmitted is used as a start trigger, the traveling condition of 30 km / h or more is set as a start condition.

  If there is ID data stored last time, the process proceeds from step S5 to step S8 to step S11, and stored in advance for each tuner (1), (2), (3), (4) with antenna. Data is preferentially determined for ID = A, B, C, and D, and then a voltage drop alarm and a puncture alarm process in steps S12 to S19 are performed. That is, after entering the automatic ID registration mode, ID = A, B, C, D stored in advance for each tuner with antenna (1), (2), (3), (4) is given priority. By making data determinable, normal tire pressure warning system control can be entered as early as possible when the tire pressure sensor is not replaced or rotated.

  On the other hand, when the voltage drop alarm or the puncture alarm is not performed (steps S16 and S18), or when there is no data of the ID stored last time and the failure diagnosis timer t passes 600 s (step S6). Or until the automatic ID registration timer T elapses for 7 minutes (step S45), the process of determining ID registration candidates in steps S20 to S29 is performed.

In other words, the first RSSI value (1) (= radio wave intensity level at the first bit position of the frame) measured by each tuner with antenna (1), (2), (3), (4) is measured. ,
Condition A: The maximum value of the first RSSI value (1) is not less than the first set value AmV (step S20).
Condition B: The difference between the maximum value of the first RSSI value (1) and the second value is equal to or larger than the second set value BmV (step S22).
If either of these is established, it is temporarily stored in the buffer 1 of the RAM 5f as an ID registration candidate (step S24).

Next, the last RSSI value (2) (= radio wave intensity level at the last bit position of the frame) measured by each tuner with antenna (1), (2), (3), (4) was measured. And
Condition C: The maximum value of the last RSSI value (2) is greater than or equal to the third set value CmV (step S25)
Condition D: The difference between the maximum value of the last RSSI value (2) and the second value is equal to or larger than the fourth set value DmV (step S27).
If both of these are established, the data temporarily held as the ID registration candidate is moved from the buffer 1 of the RAM 5f to the buffer 2 and held (step S29). If the conditions A, B, C, and D are not cleared, they are discarded as data (steps S21, S23, S26, and S28).

  As described above, in Example 1, the maximum RSSI value is equal to or greater than the threshold value with a time interval within one frame, and the difference between the maximum RSSI value (first value) and the second value is If the condition is determined to be equal to or greater than the threshold value and both conditions are satisfied, the transmission data from the tire pressure sensor set for the tire of the host vehicle is trusted and the candidate is registered as an ID registration candidate. That is, a high-accuracy ID registration candidate is obtained by using the maximum value of the reception level received by a tuner that is close to the transmitter that transmits data and has high sensitivity.

  Incidentally, for example, when a radio wave is transmitted from the transmitter of the tire pressure sensor set on the right front wheel of the adjacent vehicle, the tuners (1) and (4) with the antenna of the own vehicle are used as the tire pressure sensor of the adjacent vehicle. When the data from is received, as shown by the broken line characteristics in FIG. 7, the tuners (1) and (4) with the antenna of the own vehicle instantaneously receive data having a high radio wave intensity level. However, conditions A and B satisfying that the maximum value of the first RSSI value (1) is greater than or equal to the threshold value and the difference between the first and second values of the first RSSI value (1) is greater than or equal to the threshold value. Even if, the conditions C and D that the maximum value of the last RSSI value (2) is equal to or greater than the threshold and the difference between the first and second values of the last RSSI value (2) is equal to or greater than the threshold. Is not satisfied and the ID registration candidate data is discarded, so that even if a strong radio wave is transmitted from an adjacent vehicle, erroneous ID registration is prevented.

  If there is no tire replacement or rotation and the ID moved to the buffer 2 is the same as the ID stored last time, the process proceeds from step S30 to step S31, and in steps S31 to S35, a puncture alarm process or a data holding process is performed. Is done.

  If the tire is not replaced but the tire is rotated, the process proceeds from step S30 to step S36, and in steps S36 to S44, the ID is determined based on each four-wheel, three-wheel, or two-wheel rotation determination. Register.

  Further, when a new ID is registered by exchanging tires, the reception intensity level is also held in the buffer 2 for each frame until step S45, and data is received as an ID registration mode for 7 minutes. In step S46, if it is determined that 7 minutes have elapsed, the process proceeds from step S46 to step S47, and an ID whose average reception level is the maximum value is newly registered as an ID to be registered.

  Next, the effect will be described.

  (1) A pressure sensor 10a that is attached to each of a plurality of tires 1, 2, 3, and 4 mounted on a vehicle and detects each tire air pressure, and at least the detected tire air pressure is converted into a radio signal together with the ID of each tire. Tire pressure sensors A, B, C, and D having a transmitter 10 and a transmission antenna 10e for transmission, and are attached to the vehicle side and receive radio signals from the tire pressure sensors A, B, C, and D. In a tire pressure monitoring device comprising a receiver and a tire identification code registration means for registering the ID of each tire 1, 2, 3, 4 by storing and updating in the EEPROM 5c, the receiver comprises a plurality of tires 1, The tuners with antennas (1), (2), (3), (4) set in the vicinity of the tires 2, 3 and 4 are set as many as the number of tires. When the radio wave transmitted from the transmitter of the tire pressure sensor is received by the tuners with antennas (1), (2), (3), (4), at least twice at different times from one frame of the transmission signal Only when the received radio wave intensity is read and the relations of the received radio wave intensity read at these different times are similar to each other, the ID registration candidate is used, so the buffer capacity for temporarily storing the ID registration candidate is reduced. On the other hand, even if a high signal strength enters the tuner (1), (2), (3), (4) with the antenna of the vehicle, it is from the transmitter of the vehicle or from the transmitter of another vehicle. And accurate ID registration without erroneous registration can be performed.

  (2) The tire identification code registration means reads at least twice at different times in one frame of the transmission signal received by each tuner with antenna (1), (2), (3), (4). Only when each of the maximum received radio field strengths is greater than or equal to a preset threshold value, the maximum received radio field intensity that is closest to the transmitter and has high reception sensitivity is determined as an ID registration candidate. It is possible to select ID registration candidates with high accuracy.

  (3) The tire identification code registration means reads at least twice at different times in one frame of the transmission signal received by the tuner with each antenna (1), (2), (3), (4). Only when the difference between the maximum received radio field strength and the second-order value is equal to or greater than a preset threshold value, it is considered as an ID registration candidate, so the reception sensitivity is higher in order from the transmitter. It is possible to select an ID registration candidate with high accuracy by using the maximum value and the second value of the received radio wave intensity.

  (4) The tire identification code registration means is the first maximum received radio wave intensity within one frame of the transmission signal received by the tuner with each antenna (1), (2), (3), (4). If the difference between the maximum value and the second-order value is equal to or greater than a preset threshold, the tuners with antennas (1), (2), The maximum value of the last received radio wave intensity within one frame of the transmission signal received in (3) and (4) is greater than or equal to the preset threshold value, and the difference between the maximum value and the second value is Only when the threshold value is greater than or equal to the set threshold, it is considered as an ID registration candidate, and only when both the maximum value condition and the difference condition are satisfied at the most distant time within one frame time. By making it an ID registration candidate, selection of an incorrect ID registration candidate is surely prevented, and the accuracy is extremely high. ID registration candidates can be selected.

  As described above, the tire pressure monitoring device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and is described in each claim of the claims. Design changes and additions are allowed without departing from the scope of the present invention.

  For example, in the first embodiment, an example in which it is determined that the data is reliable as an ID registration candidate by satisfying the conditions A and B and the conditions C and D is shown. May check whether the permutation of the level received at the beginning of the frame matches the permutation of the level received at the end of the frame, and further, as shown in FIG. Since 5 frames can be received continuously, it may be confirmed that the tuner position with the maximum value that can be determined for each frame does not change between the reception of the first frame and the reception of the last frame. Furthermore, these conditions may be appropriately combined, or different condition judgments may be performed in parallel.

  In the first embodiment, in step S47, an example is shown in which an ID whose reception level average value is the maximum value is newly registered as an ID registration, but an ID whose reception level integrated value is the maximum value is shown. You may make it newly register as what should be ID-registered.

  In the embodiment, the tire pressure monitoring device in a vehicle equipped with four tires such as a passenger car is shown, but the tire pressure monitoring device in a small vehicle equipped with three tires or a large vehicle equipped with five or more tires may be used. Can be applied.

1 is an overall view showing a vehicle to which a tire pressure monitoring device according to a first embodiment is applied. 1 is a detailed view showing a tire pressure monitoring device of Example 1. FIG. It is the flowchart 1 which shows the flow of the automatic ID registration process of each tire performed with the tire pressure warning controller of Example 1. FIG. 5 is a flowchart 2 showing a flow of an automatic ID registration process for each tire executed by the tire pressure alarm controller according to the first embodiment. In the first embodiment, an example of data of one transmission (= 5 frames) in 500 ms from the transmitter is shown. In Example 1, it is a figure which shows the reading position (RSSI (1) and RSSI (2)) of the receiving intensity (= radio wave intensity) characteristic in an tuner with an antenna, and a radio wave intensity in the transmitter in Example 1. FIG. It is the figure which showed the radio wave intensity level (reception intensity level) which tuner (1), (4) with an antenna received when rotating the tire 1 time in Example 1 as a radar chart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Left front wheel tire 2 Right front wheel tire 3 Left rear wheel tire 4 Right rear wheel tire A, B, C, D Tire pressure sensor (tire pressure detection means)
(1), (2), (3), (4) Tuner with antenna (receiver)
5 Tire pressure alarm controller 5c EEPROM
5f RAM
6 Display 7 Low air pressure warning lamp 10a Pressure sensor 10b Centrifugal switch 10c ASIC
10d Transmitter (transmitter)
10e Transmitting antenna (transmitter)
11a receiving antenna 11b tuner

Claims (4)

A pressure sensor that is attached to each of a plurality of tires mounted on a vehicle and detects each tire air pressure, and a transmitter that transmits at least the detected tire air pressure together with a tire identification code for each tire by a radio signal. Tire pressure detecting means;
A receiver attached to the vehicle side for receiving a radio signal transmitted from the tire pressure detecting means;
Tire identification code registration means for registering the tire identification code of each tire by storage update to a memory;
In a tire pressure monitoring device equipped with
The receiver is set in the vicinity of each of a plurality of tires by the number of tires,
The tire identification code registration means reads at least two received radio wave intensities from one frame of the transmission signal at different times when each radio wave transmitted from the transmitter of one tire pressure detection means is received by each receiver. The tire pressure monitoring device is characterized in that it is a candidate for registration of a tire identification code only when the relationship between received radio wave intensities read at different times is similar to each other. In the tire pressure monitoring device according to claim 1,
The tire identification code registering means is configured such that each of the maximum values of the received radio wave intensity read at least twice at different times among one frame of the transmission signal received by each receiver is equal to or greater than a preset threshold value. A tire pressure monitoring apparatus characterized in that only when there is a tire identification code registration candidate. In the tire pressure monitoring device according to claim 1,
The tire identification code registration means is configured to determine whether a difference between a maximum value of received radio wave intensity and a second-order value read at least twice at different times in one frame of a transmission signal received by each receiver. A tire pressure monitoring device, characterized in that it is a candidate for registration of a tire identification code only when it is greater than or equal to a preset threshold value. In the tire pressure monitoring device according to claim 1,
The tire identification code registration means is configured such that the maximum value of the first received radio wave intensity is equal to or greater than a preset threshold value within one frame of the transmission signal received by each receiver, and the maximum value and the second value. Is greater than or equal to a preset threshold value, and the maximum value of the last received radio wave intensity within one frame of the transmission signal received by each receiver is greater than or equal to a preset threshold value. In addition, the tire pressure monitoring device is characterized in that it is a candidate for registration of a tire identification code only when the difference between the maximum value and the second-order value is equal to or greater than a preset threshold value.

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