JP4957949B2 - Tire pressure monitoring system - Google Patents

Description

  The present invention relates to a tire air pressure monitoring system for measuring air pressure in a tire inner space formed by a vehicle tire and a wheel.

  2. Description of the Related Art There is a tire pressure monitoring system that measures the air pressure in a plurality of tire spaces formed by a plurality of tires and a plurality of wheels provided in a vehicle and can monitor whether or not the air pressure is normal. A tire pressure monitoring system described in Patent Document 1 is installed in each of a plurality of tire spaces, and is installed on a vehicle body side of a plurality of tire-side transmission / reception devices each having air pressure measuring means for measuring the air pressure in the tire space. A vehicle body side transmitting / receiving device. In the tire pressure monitoring system described in Patent Document 1, first, the vehicle body side transmission / reception device transmits to the tire side transmission / reception device so as to transmit identification information unique to each tire side transmission / reception device and measurement result information using the air pressure measurement means. A transmission request is transmitted by radio. And the tire side transmission / reception apparatus which received the transmission request wirelessly transmits its identification information and measurement result information to the vehicle body side transmission / reception apparatus. In the tire pressure monitoring system described in Patent Literature 1, the vehicle body side transmission / reception device includes a transmission antenna for transmitting a transmission request for each of a plurality of tires, and the tire side transmission / reception devices in each tire are in turn. Send a send request to In other words, the vehicle body side transmission / reception device identifies the tire and then transmits a transmission request to the tire side transmission / reception device, so that the tire side transmission / reception device that returns the identification information and the measurement result information is provided at any position of the own vehicle. It is possible to determine whether the received tire side transmitting / receiving device is used.

JP 2004-268612 A

  In the tire pressure monitoring system described in Patent Document 1, in order to specify the position of the tire-side transmitting / receiving device, it is necessary to specify the tire position and then transmit a transmission request only to the tire-side transmitting / receiving device in the tire. is there. Therefore, a transmission antenna for transmitting a transmission request from the vehicle body side transmission / reception device must be installed for each of the plurality of tire side transmission / reception devices. Furthermore, in order for the vehicle body side transmission / reception device to receive the measurement result information from all the tire side transmission / reception devices provided in the vehicle in a state in which the position can be specified, the number of tire side transmission / reception devices must be the same number. A transmission request had to be made using each transmission antenna. Therefore, in the vehicle body side transmission / reception apparatus, the processing load in the request transmission process of the transmission request and the information reception process of the identification information and the measurement result information is large.

  The present invention has been made in view of the above problems, and an object thereof is to perform a request transmission process for a transmission request and an information reception process for identification information and measurement result information with a small processing load in the vehicle body side transmission / reception apparatus. The present invention is to provide a tire pressure monitoring system capable of specifying the positions of all tire-side transmitting / receiving devices.

In order to achieve the above object, the tire air pressure monitoring system according to the present invention is characterized in that a plurality of tires installed separately in a plurality of tire inner spaces formed by a plurality of tires and a plurality of wheels provided in a vehicle. A side transmission / reception device, and a vehicle body side transmission / reception device installed on the vehicle body side of the vehicle,
Each of the tire side transmission / reception devices transmits to the outside an air pressure measurement means for measuring the air pressure in the tire inner space, unique identification information given to each tire side transmission / reception device, and measurement result information by the air pressure measurement means. Tire-side transmission means, tire-side reception means for receiving a transmission request for the identification information and measurement result information from the outside, and when the tire-side reception means receives the transmission request, the tire-side transmission means Tire-side control means for performing information transmission processing for transmitting the identification information and the measurement result information to the outside,
The vehicle body side transmission / reception device includes a plurality of vehicle body side reception means for receiving the identification information and the measurement result information transmitted from the tire side transmission / reception device, and a plurality of transmission requests transmitted to the tire side transmission / reception device. Vehicle body side transmission means, vehicle body side control means for performing the information reception processing of the identification information and the measurement result information by the vehicle body side reception means, and the request transmission processing of the transmission request by the vehicle body side transmission means. A tire pressure monitoring system,
The vehicle body side transmission means is divided into a plurality of groups consisting of at least one vehicle body side transmission means that is less than the number of the tire side transmission / reception devices, and performs the request transmission processing in units of the group,
The vehicle body side receiving means is divided into a plurality of groups consisting of at least one vehicle body side receiving means less than the number of the tire side transmitting / receiving apparatuses, and the identification information transmitted from the tire side transmitting / receiving apparatus in units of the groups. And receiving the measurement result information,
The number t of the tire side transmitting / receiving devices is (2 ^m −1) × (2 ⁿ −1) ≧ t, ^where m is the number of groups of the vehicle body side transmitting means and n is the number of groups of the vehicle body side receiving means. Satisfy the relationship,
The tire-side transmission / reception device is capable of receiving the transmission request from the vehicle body-side transmission means of any group among the plurality of groups of the vehicle body-side transmission means,
The identification information and the measurement result information transmitted from the tire-side transmitting / receiving device can be received by the vehicle-body-side receiving unit of any group among a plurality of groups of the vehicle-body-side receiving unit,
Furthermore, a group of the vehicle body-side transmitting means each tire side transceiver device transmits receivable the transmission request, the identification information and the measurement result information can be received a the vehicle body is transmitted from each tire side transceiver device The combination of the groups of the side receiving means is different for each tire side transmitting / receiving device.

According to the above characteristic configuration, each tire-side transmitting / receiving device in each tire space can receive a transmission request from at least one group of the plurality of groups of the vehicle body-side transmitting means, and is transmitted from the tire-side transmitting / receiving device. Since the identification information and the measurement result information can be received by the vehicle body side reception means of any group of the vehicle body side reception means, all the tire side transmission / reception devices are transmitted from any group of the vehicle body side transmission means. The identification information and measurement result information transmitted from all the tire-side transmitting / receiving devices can be received by the vehicle body-side receiving means of any group of the vehicle body-side receiving means, that is, bidirectional communication is possible. It is possible.
The number t of the tire side transmission / reception devices is (2 ^m −1) × (2 ⁿ −1) ≧ t, ^{where m} is the number of groups of the vehicle body side transmission means and n is the number of groups of the vehicle body side reception means. Satisfying the relationship, the tire-side transmission / reception device is capable of receiving a transmission request from the vehicle-body-side transmission unit of any of the plurality of groups of the vehicle-body-side transmission unit, and from the tire-side transmission / reception device The transmitted identification information and measurement result information can be received by the vehicle body side reception unit of any one of the plurality of groups of the vehicle body side reception unit, and can be received by each tire side transmission / reception device. A group of the vehicle body side transmission means for transmitting a transmission request, and a group of the vehicle body side reception means capable of receiving the identification information and the measurement result information transmitted from each tire side transmitting / receiving device. Since the combination is different for each tire-side transmitting / receiving device, the group of the vehicle-side transmitting means that has transmitted the transmission request and the group of vehicle-body-side receiving means that has received the identification information and the measurement result information from the tire-side transmitting / receiving device. By the combination, the position of the tire-side transmitting / receiving device, that is, the position of the tire on which the tire-side transmitting / receiving device is arranged in the vehicle can be specified.
Further, as shown in the above formula, (2 ^m −1) × (2 ⁿ −1) bidirectional communication possible combinations are possible depending on the number m of the vehicle body side transmission means and the number n of the body side reception means. Yes, even if m <t and n <t with respect to the number t of tire-side transmitting / receiving devices, it is possible to reduce the number of groups m of vehicle body side transmission means and the number of groups n of vehicle body side reception means. In other words, the transmission of the transmission request is m times at the maximum, and the number of the tire-side transmission / reception devices can be smaller.
Therefore, according to the present invention, the positions of all the tire-side transmitting / receiving devices are obtained while performing the request transmission processing of the transmission request and the information receiving processing of the identification information and the measurement result information in a short processing load and in a short time in the vehicle body-side transmitting / receiving device. Can be provided.

  Another characteristic configuration of the tire pressure monitoring system according to the present invention is that the number of groups of the vehicle body side transmission means is 2, the number of groups of the vehicle body side reception means is 2, and the number of tire side transmission / reception devices is 4. In that point.

According to the above characteristic configuration, since the number of groups of the vehicle body side transmission means is 2 and the number of groups of the vehicle body side reception means is 2, (2 ² −1) × (2 ² −1) = 9 or less The position of the tire side transceiver can be specified. Therefore, the vehicle body side transmission / reception device can receive the identification information and the measurement result information while specifying the position of each tire in the four-wheeled vehicle provided with the tire side transmission / reception device.

Another characteristic configuration of the tire pressure monitoring system according to the present invention is that the transmission request transmitted by one group of the vehicle body side transmission means is provided on a right wheel side of the vehicle among the plurality of tire side transmission / reception devices. The transmission request received by the two tire-side transmitting / receiving devices and transmitted by the other group of the vehicle body-side transmitting means is provided on the left wheel side of the vehicle among the plurality of tire-side transmitting / receiving devices. Received by the two tire side transceivers,
The identification information and the measurement result information received by one group of the vehicle body side receiving means are transmitted from two tire side transmitting / receiving devices provided on the front wheel side of the vehicle among the plurality of tire side transmitting / receiving devices. The identification information and the measurement result information received by the other group of the vehicle body side receiving means are the two tire side transmission / reception units provided on the rear wheel side of the vehicle among the plurality of tire side transmission / reception devices. It is the point which is comprised so that it may transmit from an apparatus.

  According to the above characteristic configuration, when a transmission request is received by two tire-side transmission / reception devices provided on the right wheel side of the vehicle, the identification information and measurement result information transmitted by the two tire-side transmission / reception devices are: Are received separately by the group of vehicle body side receiving means provided on the front wheel side and the group of vehicle body side receiving means provided on the rear wheel side of the vehicle. Similarly, when a transmission request is received by two tire side transmission / reception devices provided on the left wheel side of the vehicle, identification information and measurement result information transmitted by the two tire side transmission / reception devices are provided on the front wheel side of the vehicle. The vehicle body side receiving means group is provided separately from the vehicle body side receiving means group provided on the rear wheel side of the vehicle. Therefore, in the vehicle body side transmission / reception device, whether the tire side transmission / reception device having the received identification information is arranged on the right wheel side or the left wheel side of the vehicle, and is arranged on the front wheel side or the rear wheel side of the vehicle. Can be identified. In addition, when the transmission timing after receiving the transmission request of the tire side transmission / reception devices provided on the front wheels and the rear wheels is different and each group of the vehicle body side reception means receives transmission signals from both tire transmission / reception devices, the reception strength The stronger signal may be determined as a transmission signal from a closer tire-side transmitting / receiving device.

Another characteristic configuration of the tire pressure monitoring system according to the present invention is that one group of the vehicle body side transmission means is arranged on the right side of the outermost metal plate constituting the right side door of the vehicle,
The other group of the vehicle body side transmitting means is that it is arranged on the left side of the outermost metal plate constituting the left side door of the vehicle.

According to the above characteristic configuration, since the outermost metal plate constituting the right side door of the vehicle functions as a shielding plate for radio waves, the radio wave transmitted by one group of the vehicle body side transmission means is transmitted to the left side of the right side door. No longer propagates to As a result, the radio waves transmitted by one group of the vehicle body side transmission means are received by the two tire side transmission / reception devices provided on the right wheel side of the vehicle, but the two tire side transmission / reception devices provided on the left wheel side are received. Depending on the device, it can be prevented from being received. Similarly, since the outermost metal plate constituting the left side door of the vehicle functions as a shielding plate for radio waves, the radio wave transmitted by the other group of the vehicle body side transmission means propagates to the right side of the left side door. Disappear. As a result, the radio wave transmitted by the other group of the vehicle body side transmission means is received by the two tire side transmission / reception devices provided on the left wheel side of the vehicle, but the two tire side transmission / reception devices provided on the right wheel side. Depending on the device, it can be prevented from being received.
Therefore, the tire side transmission / reception device can selectively receive a transmission request from a specific group among a group of a plurality of vehicle body side transmission means.

  Another characteristic configuration of the tire pressure monitoring system according to the present invention is that the vehicle body side transmitting means, the vehicle body side receiving means, and the vehicle body side control means of the vehicle body side transmitting / receiving device use a wireless key. The transmission antenna, the reception antenna, and the control circuit unit that processes the signals transmitted and received between the transmission antenna and the reception antenna are included in the unlocking and locking system for unlocking and locking the side door. It is in the point which is comprised.

  According to the above characteristic configuration, the device configuration of the unlocking and locking system existing in the vehicle can be used as the device configuration of the tire pressure monitoring system, so that the device cost of the tire pressure monitoring system can be reduced.

<First Embodiment>
A tire pressure monitoring system according to a first embodiment will be described below with reference to the drawings.
FIG. 1 is a functional block diagram of a tire pressure monitoring system. The tire pressure monitoring system is separately installed in a plurality of tire inner spaces 4 (4a to 4d) formed by a plurality of tires 2 (2a to 2d) and a plurality of wheels 3 (3a to 3d) provided in the vehicle 1. A plurality of tire side transmitting / receiving devices 10 (10a to 10d) and a vehicle body side transmitting / receiving device 55 installed on the vehicle body 5 side of the vehicle 1 are provided. FIG. 2 is a functional block diagram of the tire side transceiver 10. The configuration of each tire-side transmitting / receiving device 10 (10a to 10d) installed in the plurality of tire inner spaces 4 (4a to 4d) is the same.

The tire-side transmitting / receiving device 10 (10a to 10d) uses the unique identification information given to each tire-side transmitting / receiving device 10 (10a to 10d) and the measurement result information by the sensor unit 17 as the tire inner space 4 (4a to 4d). A transmission circuit unit 13 and a transmission antenna 14 for wireless transmission to the outside, and a reception antenna 16 and a reception circuit unit 15 for receiving a transmission request for measurement result information from the outside, and transmitting and receiving information to and from the outside It is comprised so that it can do. The tire-side transmitting / receiving device 10 (10a to 10d) includes a sensor unit 17 as an air pressure sensor that measures the air pressure in the tire inner space 4 (4a to 4d), and the tire-side transmitting / receiving device 10 (10a to 10d). When the storage unit 11 that stores information to be handled (identification information, measurement result information, etc.) and the reception antenna 16 and the reception circuit unit 15 receive a transmission request from the outside, the vehicle is sent to the transmission antenna 14 and the transmission circuit unit 13. And a control circuit unit 12 for performing an information transmission process for transmitting the identification information and the measurement result information to the outside.
As described above, the sensor unit 17 corresponds to the air pressure measurement unit of the present invention, the transmission antenna 14 corresponds to the tire side transmission unit of the present invention, and the reception antenna 16 corresponds to the tire side reception unit of the present invention. The circuit unit 12 corresponds to the tire side control means of the present invention.

The vehicle body side transmission / reception device 55 includes a reception antenna 21 (21e, 21f) that receives identification information and measurement result information transmitted from the tire side transmission / reception device 10 (10a to 10d), and the tire side transmission / reception device 10 (10a to 10d). And a transmission antenna 22 (22e, 22f) for transmitting a transmission request. Further, the vehicle body side transmission / reception device 55 stores information (such as identification information and measurement result information received from the tire side transmission / reception device 10 (10a to 10d)) handled inside the vehicle body side transmission / reception device 55; Information reception processing of identification information and measurement result information by the reception antenna 21 (21e, 21f) and the reception circuit units 31, 32, and request transmission processing of a transmission request by the transmission antenna 22 (22e, 22f) and the transmission circuit units 56, 57 ECU (electronic control unit) 25 which performs.
As described above, the reception antenna 21 (21e, 21f) corresponds to the vehicle body side reception means of the present invention, the transmission antenna 22 (22e, 22f) corresponds to the vehicle body side transmission means of the present invention, and the storage unit 35 is the vehicle body. The ECU 25 corresponds to vehicle side control means.

Below, the specific structure of the vehicle body side transmission / reception apparatus 55 and the tire side transmission / reception apparatus 10 (10a-10d) is demonstrated.
The vehicle body side transmission / reception device 55 transmits a request for transmission of identification information and measurement result information to each tire side transmission / reception device 10 (10a to 10d), and receives the returned identification information and measurement result information. The information regarding the tire pressure of 1 is acquired. And the measurement result information which the vehicle body side transmission / reception apparatus 55 acquired is displayed on the display apparatus 6 provided in the vehicle 1 so that the passenger | crew of the vehicle 1 can recognize. At this time, as will be described later, the display device 6 also displays in a recognizable manner where the information regarding the tire air pressure is in the tire inner space 4 provided in the vehicle 1. In addition to the measurement result information, the identification information may be displayed on the display device 6. The transmission circuit units 56 and 57 perform modulation processing of the transmission request, and the reception circuit units 31 and 32 perform demodulation processing of signals received by the reception antennas 21e and 21f.

  The control circuit unit 12 of the tire side transmitting / receiving device 10 (10a to 10d) causes the storage unit 11 to accumulate measurement result information regarding the air pressure of the tire inner space 4 (4a to 4d) measured by the sensor unit 17 at a predetermined timing. . And if a transmission request is received from the vehicle body side transmission / reception apparatus 55 via the receiving antenna 16, the measurement result information memorize | stored in the memory | storage part 11 and the identification information of own tire side transmission / reception apparatus 10 (10a-10d) will be transmitted. Information transmission processing for wireless transmission to the outside via the antenna 14 is performed. In addition, the reception circuit unit 15 and the transmission circuit unit 13 of the tire-side transmission / reception device 10 (10a to 10d) perform demodulation processing of received signals and modulation processing of signals to be transmitted.

  Further, in the tire pressure monitoring system of the present embodiment, the identification information and the measurement result information received by the vehicle body side transmitting / receiving device 55 are located at any position of the vehicle 1 (in the present embodiment, right front, right rear, left front, left rear). It has a function of discriminating whether it is sent from the provided tire side transmitting / receiving device 10. Therefore, the vehicle body side transmission / reception device 55 includes a plurality of vehicle body side reception means (reception antenna 21e and reception antenna 21f) for receiving measurement result information transmitted from the tire side transmission / reception device 10 (10a to 10d), and the vehicle 1 It has a plurality of vehicle body side transmission means (transmission antenna 22e and transmission antenna 22f) which transmit a transmission request to a plurality of tire side transceivers 10 (10a-10d) provided.

Next, in the tire pressure monitoring system of the present embodiment, the tire-side transceiver 10 (10a) after the vehicle body-side transceiver 55 transmits a transmission request to the plurality of tire-side transceivers 10 (10a to 10d). 10d) and the operation of the vehicle body side transmitting / receiving device 55 will be described.
As described above, in the tire pressure monitoring system of the present embodiment, the identification information and the measurement result information received by the vehicle body side transmitting / receiving device 55 indicate the position of the vehicle 1 (in the present embodiment, right front, right rear, left front, left It is necessary to determine whether the transmission is from the tire-side transmitting / receiving device 10 (10a to 10d) provided in the rear). In the tire pressure monitoring system of the present embodiment, the transmission antennas 22e and 22f as the vehicle body side transmission means are divided into a plurality of groups including at least one transmission antenna 22 that is smaller than the number of the tire side transmission / reception devices 10, and the group. The request transmission process is performed in units. Further, the receiving antennas 21e and 21f as the vehicle body side receiving means are divided into a plurality of groups including at least one receiving antenna 21 which is smaller than the number of the tire side transmitting / receiving devices 10, and the tire side transmitting / receiving devices 10 are grouped in units. The transmitted identification information and measurement result information are received.
And the tire side transmission / reception apparatus 10 (10a-10d) can receive a transmission request from the transmission antenna 22 of any group among the several groups of the transmission antenna 22 (22e, 22f). Further, the identification information and the measurement result information transmitted from the tire-side transmitting / receiving device 10 can be received by the reception antenna 22 of any one of the plurality of groups of the reception antennas 21e and 21f.
Further, a group of transmission antennas 22 that transmit transmission requests that can be received by each tire-side transceiver 10 and a group of reception antennas 21 that can receive identification information and measurement result information transmitted from each tire-side transceiver 10. The combination differs for each tire-side transmitting / receiving device 10.

Specifically, in the present embodiment illustrated in FIG. 1, since the vehicle 1 is a four-wheel vehicle, the tire 2 and the wheel 3 are four sets, that is, the number of the tire-side transmission / reception devices 10 is four. The number of transmission antennas 22 as vehicle body side transmission means included in the vehicle body side transmission / reception device 55 is two, and the number of reception antennas 21 as vehicle body side reception means is two. Of the two receiving antennas 21, the receiving antenna 21e on the front wheel side is provided on the front side of the center of the wheel base of the vehicle, and the receiving antenna 21f on the rear wheel side is on the rear side of the center of the wheel base of the vehicle. Is provided. And the transmission request received by the two tire side transmission / reception devices 10a, 10b provided on the right wheel side of the vehicle 1 among the plurality of tire side transmission / reception devices 10 (10a to 10d) Transmitted by the transmitting antenna 22e. The transmission request received by the two tire side transmission / reception devices 10c and 10d provided on the left wheel side of the vehicle 1 among the plurality of tire side transmission / reception devices 10 (10a to 10d) is transmitted from the vehicle body side transmission / reception device 55. Transmitted by the antenna 22f.
That is, in the present embodiment, each of the transmission antenna 22e and the transmission antenna 22f constitutes a group (that is, the number of groups is 2), and the request is made in units of groups (that is, the transmission antenna 22e and the transmission antenna 22f are separately provided). Perform transmission processing. And the tire side transmission / reception device 10a and the tire side transmission / reception device 10b can receive a transmission request from the transmission antenna 22e of one group, and the tire side transmission / reception device 10c and the tire side transmission / reception device 10d are transmitted from the transmission antenna 22f of the other group. A transmission request can be received.

Similarly, the identification information and the measurement result information received by the receiving antenna 21e of the vehicle body side transmission / reception device 55 include two pieces of information provided on the front wheel side of the vehicle 1 among the plurality of tire side transmission / reception devices 10 (10a to 10d). It is transmitted from the tire side transceiver 10a, 10c. Further, the identification information and the measurement result information received by the receiving antenna 21f of the vehicle body side transmission / reception device 55 are two of the plurality of tire side transmission / reception devices 10 (10a to 10d) provided on the rear wheel side of the vehicle 1. It is transmitted from the tire side transceiver 10b, 10d.
That is, in the present embodiment, the receiving antenna 21e and the receiving antenna 21f each constitute a group (that is, the number of groups is 2), and the tire side in units of the group (that is, the receiving antenna 21e and the receiving antenna 21f are separately provided). The identification information and the measurement result information transmitted from the transmission / reception device 10 are received. The identification information and measurement result information transmitted from the tire-side transmitting / receiving device 10a and the tire-side transmitting / receiving device 10c can be received by the receiving antenna 21e of one group and transmitted from the tire-side transmitting / receiving device 10b and the tire-side transmitting / receiving device 10d. The identification information and measurement result information to be received can be received by the receiving antenna 21f of the other group.
The relationship between the tire-side transmitting / receiving device 10 (10a to 10d) and the vehicle body-side transmitting / receiving device 55 is summarized as shown in Table 1 below. However, “◯” indicates that communication is possible, and “X” indicates that communication is not possible.

  As described above, in this embodiment, a group of transmission antennas 22 that transmit transmission requests that can be received by each tire-side transmitting / receiving device 10, and identification information and measurement result information transmitted from each tire-side transmitting / receiving device 10 are received. The possible combinations of groups of receiving antennas 21 are different for each tire-side transmitting / receiving device 10. As a result, as shown in Table 1, when a transmission request is transmitted from any of the transmission antennas 22 included in the vehicle body side transmission / reception device 55, which reception antenna 21 receives the identification information from the tire side transmission / reception device 10 (10a to 10d) and By analyzing whether the measurement result information is received, it is possible to determine at which position of the vehicle 1 the tire-side transmitting / receiving device 10 (10a to 10d) having the identification information is provided.

Next, when the number of sets of tires 2 and wheels 3, that is, the number of tire-side transmission / reception devices 10 is t, the number of groups of transmission antennas 22 of the vehicle-body-side transmission / reception device 55 arranged as described above (that is, The number of groups of vehicle body side transmission means) and the number of groups of receiving antennas 21 (that is, the number of groups of vehicle body side reception means), the position of the tire side transmission / reception device 10 (10a to 10d) can be specified. Will be described. In this embodiment, when the number of groups of the transmission antennas 22 of the vehicle body side transmission / reception device 55 is m, there are 2 ^m combinations in which the ^m transmission antennas 22 transmit and do not transmit a transmission request. However, if at least one of the m transmitting antennas 22 does not transmit a transmission request, the identification information and the measurement result information are not returned from the tire-side transmitting / receiving device 10 (10a to 10d). However, it is necessary to exclude one case where the transmission request is not transmitted. Therefore, in the present embodiment, there are (2 ^m −1) combinations when m transmission antennas 22 transmit a transmission request and when no transmission request is transmitted.
Similarly, when the number of groups of the receiving antennas 21 of the vehicle body side transmission / reception device 55 is n, there are 2 ⁿ combinations when the n receiving antennas 21 receive the identification information and the measurement result information and do not receive them. . However, since at least one of the n reception antennas 21 must receive the identification information and the measurement result information from the tire-side transmission / reception device 10 (10a to 10d), all the n reception antennas 21 have the identification information and It is necessary to exclude one case where measurement result information is not received. Therefore, in the present embodiment, there are (2 ⁿ −1) combinations when the n reception antennas 21 receive the identification information and the measurement result information and when they do not.
Accordingly, when the number of the tire-side transmitting / receiving devices 10 is t, the number of groups of the transmitting antennas 22 of the vehicle-body-side transmitting / receiving device 55 is set so as to satisfy the relationship of (2 ^m −1) × (2 ⁿ −1) ≧ t. m and the number of groups of the receiving antennas 21 of the vehicle body side transmission / reception device 55 may be n. That is, in order to specify the positions of the t tire-side transmission / reception devices, a group of m vehicle body-side transmission units that satisfy the relationship of (2 ^m −1) × (2 ⁿ −1) ≧ t and n There may be a group of vehicle body side receiving means.

Second Embodiment
The tire air pressure monitoring system of the second embodiment is different from the first embodiment in the configuration of the transmission antenna and the reception antenna of the vehicle body side transmitting / receiving device. The tire pressure monitoring system of the second embodiment will be described below, but the description of the same configuration as that of the first embodiment will be omitted.

  FIG. 3 is a functional block diagram of the tire pressure monitoring system according to the second embodiment. In the second embodiment, the vehicle body side transmission / reception device 20 includes four transmission antennas 22 (22a to 22d) as vehicle body side transmission means and four reception antennas 21 (21a to 21d) as vehicle body side reception means. In the present embodiment, the four transmission antennas 22 (22a to 22d) of the vehicle body side transmitting / receiving device 20 are provided on the vehicle body 5 side in the vicinity of the tire 2 (2a to 2d) attached to the vehicle 1. . This is because the reach of radio waves transmitted from the transmission antennas 22 (22a to 22d) of the vehicle body side transmitting / receiving device 20 is short. That is, the transmission request transmitted wirelessly from each transmission antenna 22 (22a to 22d) of the vehicle body side transmission / reception device 20 is individually transmitted to the tire side transmission / reception device 10 (10a to 10d) installed in the vicinity thereof. Will be. The four receiving antennas 21 (21a to 21d) of the vehicle body side transmitting / receiving device 20 are also provided on the vehicle body 5 side in the vicinity of the tire 2 (2a to 2d) attached to the vehicle 1. This is also because the reach distance of radio waves transmitted wirelessly from the tire-side transmitting / receiving device 10 (10a to 10d) is short. That is, each receiving antenna 21 (21a to 21d) of the vehicle body side transmitting / receiving device 20 is individually provided in the vicinity of each tire side transmitting / receiving device 10 (10a to 10d).

Two receiving antennas 21a and 21c provided on the front wheel side of the vehicle 1 are connected to a receiving circuit unit 23 via a combiner 28, and two receiving antennas 21b and 21d provided on the rear wheel side of the vehicle 1 are combined. It is connected to the receiving circuit unit 23 via the device 29. Here, the receiving antennas 21a and 21c are provided on the front side of the center of the vehicle wheel base, and the receiving antennas 21b and 21d are provided on the rear side of the center of the wheel base of the vehicle. The synthesizers 28 and 29 are for synthesizing two signals into one. However, the receiving circuit unit 23 switches between a state in which communication is possible between the two reception antennas 21a, 21c on the front wheel side and a state in which communication is possible between the two reception antennas 21b, 21d on the rear wheel side. An antenna selector section 23a. That is, the receiving circuit unit 23 selectively switches between the state of receiving radio waves with the front-wheel-side receiving antennas 21a and 21c and the state of receiving radio waves with the rear-wheel-side receiving antennas 21b and 21d with the antenna selector unit 23a. ing.
That is, in the present embodiment, the vehicle body side transmitting / receiving device 20 has two vehicle body side receiving means (receiving antenna 21a and receiving antenna 21c) on the front wheel side, and two vehicle body side receiving means (receiving antenna 21b and receiving antenna 21b) on the rear wheel side. It has a receiving antenna 21d).

Similarly, two transmission antennas 22a and 22b provided on the right side of the vehicle 1 are connected to the transmission circuit unit 24 via a distributor 26, and two transmission antennas 22c and 22d provided on the left side of the vehicle 1 are distributed. It is connected to the transmission circuit unit 24 via the device 27. The distributors 26 and 27 are for distributing one signal to the same two signals. However, the transmission circuit unit 24 switches between a state in which communication is possible between the two transmission antennas 22a, 22b on the right wheel side and a state in which communication is possible between the two transmission antennas 22c, 22d on the left wheel side. An antenna selector section 24a. That is, the transmission circuit unit 24 selectively switches the state of transmitting radio waves from the right-wheel side transmission antennas 22a and 22b and the state of transmitting radio waves from the left-wheel side transmission antennas 22c and 22d by the antenna selector unit 24a. ing.
That is, in the present embodiment, the vehicle body side transmission / reception device 20 has two vehicle body side transmission means (transmission antenna 22a and transmission antenna 22b) on the right wheel side, and two vehicle body side transmission means (transmission antenna 22b and transmission antenna 22b on the left wheel side). It has a transmission antenna 22d).

Therefore, in this embodiment, the receiving antenna 21a and the receiving antenna 21c constitute one group, and receive identification information and measurement result information transmitted from the tire-side transmitting / receiving device 10a and the tire-side transmitting / receiving device 10c for each group. . And the receiving antenna 21b and the receiving antenna 21d comprise the other group, and receive the identification information and measurement result information transmitted from the tire side transmission / reception device 10b and the tire side transmission / reception device 10d in the group unit.
Further, the transmission antenna 22a and the transmission antenna 22b constitute one group and perform the request transmission process in units of the group. The transmission antenna 22c and the transmission antenna 22d constitute the other group, and perform the request transmission process in units of the group.

  Similar to the first embodiment, the relationship between the tire side transmitting / receiving device 10 (10a to 10d) and the vehicle body side transmitting / receiving device 20 is summarized as shown in Table 2 below. However, “◯” indicates that communication is possible, and “X” indicates that communication is not possible.

  As described above, also in the present embodiment, the tire-side transmission / reception device 10 can receive a transmission request from the transmission antenna 22 of any group among the plurality of groups of the transmission antennas 22. The transmitted identification information and measurement result information can be received by the reception antenna 21 of any one of the plurality of groups of the reception antennas 21. And the group of the transmission antenna 22 which transmits the transmission request which each tire side transmission / reception apparatus 10 can receive, and the group of the reception antenna 21 which can receive the identification information and measurement result information transmitted from each tire side transmission / reception apparatus 10 The combination differs for each tire-side transmitting / receiving device 10. As a result, as shown in Table 2, when a transmission request is transmitted from any of the transmission antennas included in the vehicle body side transmission / reception device 20, which reception antenna is identified from the tire side transmission / reception device 10 (10a to 10d) and measurement results. By analyzing whether the information is received, it is possible to determine in which position of the vehicle 1 the tire-side transmitting / receiving device 10 (10a to 10d) having the identification information is provided.

<Third Embodiment>
The tire air pressure monitoring system of the third embodiment is different from the second embodiment in the configuration of the receiving antenna of the vehicle body side transmitting / receiving device. The tire pressure monitoring system of the third embodiment will be described below, but the description of the same configuration as that of the second embodiment will be omitted.

FIG. 4 is a functional block diagram of the tire pressure monitoring system according to the third embodiment. In the tire pressure monitoring system of the present embodiment, the vehicle body side transmitting / receiving device 30 includes two receiving circuit units 31 and 32. In the third embodiment, the vehicle body side transmitting / receiving apparatus 30 includes four transmission antennas 22 (22a to 22d) as vehicle body side transmission means and four reception antennas 21 (21a to 21d) as vehicle body side reception means. In the present embodiment, the four transmission antennas 22 (22a to 22d) of the vehicle body side transmitting / receiving device 30 are provided on the vehicle body 5 side in the vicinity of the tire 2 (2a to 2d) attached to the vehicle 1. . The two receiving antennas 21 a and 21 c provided on the front wheel side are connected to the receiving circuit unit 31 via the combiner 28. Similarly, the two receiving antennas 21 b and 21 d provided on the rear wheel side are connected to the receiving circuit unit 32 via the combiner 29. The receiving circuit unit 31 and the receiving circuit unit 32 are connected to the ECU 25 separately. Thus, the two receiving antennas 21a and 21c provided on the front wheel side and the two receiving antennas 21b and 21d provided on the rear wheel side are connected to the ECU 25 via the separate receiving circuit units 31 and 32. Thus, the ECU 25 can simultaneously receive two pieces of identification information and measurement result information from the reception antenna 21a and the reception antenna 21b. On the other hand, in the second embodiment, for example, the receiving antenna 21a and the receiving antenna 21b are configured such that only one of the receiving antenna 21a and the receiving antenna 21b is selected by the antenna selector 23a. Two identification information and measurement result information could not be received simultaneously.
As described above, in the present embodiment, the vehicle body side transmission / reception device 30 has two vehicle body side reception means (reception antenna 21a and reception antenna 21c) on the front wheel side, and two vehicle body side reception means (reception) on the rear wheel side. The antenna 21b and the receiving antenna 21d) are separately provided.

Therefore, in this embodiment, the receiving antenna 21a and the receiving antenna 21c constitute one group, and receive identification information and measurement result information transmitted from the tire-side transmitting / receiving device 10a and the tire-side transmitting / receiving device 10c for each group. . And the receiving antenna 21b and the receiving antenna 21d comprise the other group, and receive the identification information and measurement result information transmitted from the tire side transmission / reception device 10b and the tire side transmission / reception device 10d in the group unit.
Further, the transmission antenna 22a and the transmission antenna 22b constitute one group and perform the request transmission process in units of the group. The transmission antenna 22c and the transmission antenna 22d constitute the other group, and perform the request transmission process in units of the group.

  Similar to the second embodiment, the relationship between the tire side transmitting / receiving device 10 (10a to 10d) and the vehicle body side transmitting / receiving device 30 is summarized as shown in Table 3 below. However, “◯” indicates that communication is possible, and “X” indicates that communication is not possible.

  As described above, also in the present embodiment, the tire-side transmission / reception device 10 can receive a transmission request from the transmission antenna 22 of any group among the plurality of groups of the transmission antennas 22. The transmitted identification information and measurement result information can be received by the reception antenna 21 of any one of the plurality of groups of the reception antennas 21. And the group of the transmission antenna 22 which transmits the transmission request which each tire side transmission / reception apparatus 10 can receive, and the group of the reception antenna 21 which can receive the identification information and measurement result information transmitted from each tire side transmission / reception apparatus 10 The combination differs for each tire-side transmitting / receiving device 10. In the tire pressure monitoring system according to the present embodiment, the ECU 25 can simultaneously receive two pieces of identification information and measurement result information from the receiving antenna 21a and the receiving antenna 21b (or the receiving antenna 21c and the receiving antenna 21d). For example, in the second embodiment, a request transmission process for transmitting a transmission request from the transmission antennas 22a and 22b with the distributor 26 selected by the antenna selector unit 24a, and a state in which the distributor 27 is selected by the antenna selector unit 24a Therefore, it is necessary to perform the request transmission process of transmitting a transmission request from the transmission antennas 22c and 22d twice, a total of four times. However, in the present embodiment, the vehicle body side transmitting / receiving device 30 includes a request transmission process for transmitting a transmission request from the transmission antennas 22a and 22b in a state where the distributor 26 is selected by the antenna selector unit 24a, and a distributor by the antenna selector unit 24a. In the state where 27 is selected, it is only necessary to perform two request transmission processes called request transmission processes for transmitting transmission requests from the transmission antennas 22c and 22d. Therefore, the number of request transmission processes of the vehicle body side transmitting / receiving device 30 can be reduced. Moreover, since the number of times of information transmission processing of the tire side transmitting / receiving device 10 is reduced, the power consumption in the tire pressure monitoring system 10 can be reduced.

<Fourth embodiment>
The tire air pressure monitoring system of the fourth embodiment is different from the third embodiment in the configuration of the receiving antenna of the vehicle body side transmitting / receiving device. The tire pressure monitoring system of the fourth embodiment will be described below, but the description of the same configuration as that of the third embodiment will be omitted.

  FIG. 5 is a functional block diagram of the tire pressure monitoring system according to the fourth embodiment. In the fourth embodiment, the vehicle body side transmitting / receiving device 40 includes two receiving antennas 21 (21e, 21f) as two vehicle body side receiving means. The reception antenna 21e provided on the front wheel side of the vehicle 1 is connected to the ECU 25 via the reception circuit unit 31, and the reception antenna 21f provided on the rear wheel side of the vehicle 1 is connected to the ECU 25 via the reception circuit unit 32. Connected. Here, the receiving antenna 21e is capable of receiving radio waves transmitted from the tire-side transmitting / receiving devices 10a and 10c provided on the front wheel side of the vehicle 1, and the receiving antenna 21f is provided on the rear wheel side of the vehicle 1. The radio waves transmitted from the tire-side transmitting / receiving devices 10b and 10d can be received. In other words, in the present embodiment, the vehicle body side transmitting / receiving device 40 has one vehicle body side receiving means (receiving antenna 21e) on the front wheel side and one vehicle body side receiving means (receiving antenna 21f) on the rear wheel side. Will be.

Therefore, in this embodiment, the receiving antenna 21e forms one group, and receives identification information and measurement result information transmitted from the tire-side transmitting / receiving device 10a and the tire-side transmitting / receiving device 10c in units of groups. And the receiving antenna 21f comprises the other group, and receives the identification information and measurement result information transmitted from the tire side transmission / reception device 10b and the tire side transmission / reception device 10d in the group unit.
Further, the transmission antenna 22a and the transmission antenna 22b constitute one group and perform the request transmission process in units of the group. The transmission antenna 22c and the transmission antenna 22d constitute the other group, and perform the request transmission process in units of the group.

  Table 4 below summarizes the relationship between the tire-side transmitting / receiving device 10 (10a to 10d) and the vehicle-body-side transmitting / receiving device 40 described above. However, “◯” indicates that communication is possible, and “X” indicates that communication is not possible.

  As described above, also in the present embodiment, the tire-side transmission / reception device 10 can receive a transmission request from the transmission antenna 22 of any group among the plurality of groups of the transmission antennas 22. The transmitted identification information and measurement result information can be received by the reception antenna 21 of any one of the plurality of groups of the reception antennas 21. And the group of the transmission antenna 22 which transmits the transmission request which each tire side transmission / reception apparatus 10 can receive, and the group of the reception antenna 21 which can receive the identification information and measurement result information transmitted from each tire side transmission / reception apparatus 10 The combination differs for each tire-side transmitting / receiving device 10.

<Fifth Embodiment>
The tire air pressure monitoring system of the fifth embodiment is different from the second embodiment in the configuration of the transmitting antenna and the receiving antenna of the vehicle body side transmitting / receiving device. The tire pressure monitoring system of the fifth embodiment will be described below, but the description of the same configuration as that of the second embodiment will be omitted.

FIG. 6 is a functional block diagram of the tire pressure monitoring system according to the fifth embodiment. In the vehicle body side transmission / reception device 50 of this embodiment, the transmission antennas 22a and 22b and the distributor 26 of the vehicle body side transmission / reception device 20 described in the second embodiment with reference to FIG. 3 are replaced with one transmission antenna 22e of this embodiment. Similarly, the transmission antennas 22c and 22d and the distributor 27 of the vehicle body side transmitting / receiving device 20 are replaced with one transmission antenna 22f of the present embodiment. Further, the receiving antennas 21a and 21c and the combiner 28 of the vehicle body side transmitting / receiving device 20 described in the second embodiment with reference to FIG. 3 are replaced with one receiving antenna 21e of the present embodiment, and the vehicle body side transmitting / receiving device 20 is also the same. The receiving antennas 21b and 21d and the combiner 29 are replaced with one receiving antenna 21f of the present embodiment.
With this configuration, the number of transmission antennas and reception antennas included in the vehicle body side transmission / reception device 50 is reduced, so that there is an advantage that the device cost can be reduced.

<Sixth Embodiment>
The tire pressure monitoring system of the sixth embodiment is a modification of the arrangement of the four transmitting antennas included in the vehicle body side transmitting / receiving apparatus described in the fourth embodiment with reference to FIG. The tire pressure monitoring system of the sixth embodiment will be described below, but the description of the same configuration as that of the fourth embodiment will be omitted.

FIG. 7 is a functional block diagram of the tire pressure monitoring system according to the sixth embodiment. As shown in FIG. 7, the vehicle body side transmission / reception device 60 includes four transmission antennas 61 (61a to 61d). FIG. 8 is a diagram for explaining the installation position of the transmission antenna 61a included in the vehicle body side transmission / reception device 60 shown in FIG. Specifically, the four transmission antennas 61 (61a to 61d) are provided outside the outermost metal plates 63 (63a to 63d) constituting the side door 62 (62a to 62d). FIG. 8 shows only the installation position of the transmission antenna 61a provided on the front side of the right wheel side among the four transmission antennas 61 (61a to 61d), but the other transmission antennas 61b, 61c, 61d Since the installation form is the same as that of the transmission antenna 61a, illustration and description thereof are omitted. As shown in FIG. 8, the transmission antenna provided on the front side on the right wheel side of the vehicle 1 among the transmission antennas 61 (61 a to 61 d) as the vehicle body side transmission means included in the vehicle body side transmission / reception device 60 shown in FIG. 7. The group 61a is arranged on the right side of the outermost metal plate 63a constituting the right side door 62a of the vehicle 1.
Specifically, the transmission antenna 61a is provided inside a door handle 64 provided on the surface of the metal plate 63a of the right side door. That is, since the metal plate 63a constituting the right side door 62a functions as a shielding plate for radio waves, the radio wave transmitted by the transmission antenna 61a does not propagate to the left side of the right side door 62a. As a result, it is ensured that the vehicle body side transmission / reception device 60 can make a transmission request only to the desired tire side transmission / reception device 10 (here, the tire side transmission / reception device 10a).

Although not shown because it is the same as the configuration of the transmission antenna 61a, the transmission antenna 61b provided on the rear side of the right wheel side of the vehicle 1 is the outermost side constituting the right side door 62b of the vehicle 1. It is arrange | positioned in the door handle of the right side of the metal plate 63b. The transmission antenna 61c provided on the front side of the left wheel side of the vehicle 1 is disposed in the door handle on the left side of the outermost metal plate 63c constituting the left side door 62c of the vehicle 1, The transmission antenna 61d provided on the rear side is disposed in the door handle on the left side of the outermost metal plate 63d constituting the left side door 62d of the vehicle 1. In this way, one group formed by the transmission antennas 61a and 61b as the vehicle body side transmission means is arranged on the right side of the outermost metal plates 63a and 63b constituting the right side doors 62a and 62b of the vehicle 1, Similarly, the other group constituted by the transmission antennas 61c and 61d as the vehicle body side transmission means is arranged on the left side of the outermost metal plates 63c and 63d constituting the left side doors 62c and 62d of the vehicle 1.
As described above, the vehicle body side transmission / reception device 60 can surely make a transmission request only to the desired tire side transmission / reception device 10 among the plurality of tire side transmission / reception devices 10 (10a to 10d).

  Moreover, in this embodiment, the unlocking and locking system which unlocks and locks the side door 62 (62a-62d) of the vehicle 1 using the wireless key is constructed in the vehicle 1. The unlocking and locking system has a wireless portable device (not shown) that functions as an electronic key for verifying that the vehicle occupant is an occupant, and is an operation switch mounted on the door handle 64. If the driver 66 is operated, the side door 62 is unlocked, and if the passenger gets out of the vehicle 1 and operates the operation switch 66, the side door 62 is locked. Alternatively, an electrostatic capacitance type contact detection sensor may be provided on the door handle 64, and the side door 62 may be unlocked when an occupant carrying the portable device comes into contact with the contact detection sensor. Specifically, in this system, an identification signal unique to the portable device is stored, and when the portable device receives an identification signal transmission request from the vehicle 1 side, the portable device wirelessly transmits the identification signal of confidence to the vehicle 1 side. . On the vehicle 1 side, the identification signal of the portable device is authenticated based on the identification information transmitted from the portable device. On the vehicle 1 side, if the identification signal is valid, the side door 62 is opened on condition that the above-described human operation (operation of the operation switch 66, contact with the door handle 64, etc.) has been performed. Unlock. The side door 62 can also be unlocked and locked by inserting a key into a key cylinder 65 provided on the door handle 64 and rotating it. Some of the side doors 62 (62a to 62d) are not provided with the key cylinder 65.

As described above, in the unlocking and locking system described above, the vehicle 1 side receives vehicle body side transmission means (such as a transmission antenna) for transmitting an identification signal transmission request to the portable device, and receives the identification signal from the portable device. And a control circuit unit such as an ECU for processing signals transmitted and received between the vehicle body side transmission unit and the vehicle body side reception unit.
Here, the tire pressure monitoring system described above is necessary for notifying the occupant of the air pressure in the tire inner space 4 (4a to 4d) when the vehicle 1 is traveling, and the unlocking and locking system described above is Necessary when stopping. Further, both of them require a vehicle body side transmission means (transmission antenna or the like), a vehicle body side reception means (reception antenna or the like), and an ECU. Therefore, in the present embodiment, the vehicle body side transmission means, the vehicle body side reception means, and the vehicle body side control means (ECU) included in the vehicle body side transmission / reception device 60 are the vehicle body side transmission means, the vehicle body side reception means, and the unlocking and locking system. The control circuit unit that processes signals transmitted and received by the vehicle body side transmission unit and the vehicle body side reception unit is configured to be used in combination.
Therefore, since the device configuration of the above-described unlocking and locking system existing in the vehicle 1 can be used as the device configuration of the tire pressure monitoring system, the cost of the tire pressure monitoring system can be reduced.

<Another embodiment>
<1>
In the above embodiment, the case where the sensor unit 17 is an air pressure sensor that measures the air pressure in the tire inner space 4 has been described. However, a temperature sensor, a voltage sensor, and the like may be additionally provided. In this case, the control circuit unit 12 of the tire side transceiver 10 (10a to 10d) can correct the air pressure measured by the air pressure sensor based on the measurement result of the temperature sensor. In that case, the control circuit unit 12 of the tire-side transmitting / receiving apparatus 10 stores the corrected air pressure in the storage unit 11 based on the measurement result of the temperature sensor. Moreover, a voltage sensor measures the voltage value of the internal power supply (not shown) of the tire side transmission / reception apparatus 10 (10a-10d). Then, by transmitting the air pressure value, the voltage value and the like together with the air pressure value as measurement result information from the tire side transmitting / receiving device 10 (10a to 10d) to the vehicle body side transmitting / receiving device, the information is displayed on the display device 6.

<2>
In the above embodiment, the case where the vehicle body side transmission / reception apparatus has two or four vehicle body side transmission means and two or four vehicle body side reception means has been described. However, the number of vehicle body side transmission means and the number of vehicle body side reception means The number can be changed as appropriate. For example, the vehicle body side transmission / reception means may be modified to have three vehicle body side transmission means and one vehicle body side reception means.
Moreover, although the four-wheeled vehicle was illustrated in the said embodiment, the number of wheels (namely, the number of tire side transmission / reception apparatuses) may be any number. For example, the tire pressure monitoring system of the present invention can be provided for a vehicle such as six wheels.

Functional block diagram of the tire pressure monitoring system of the first embodiment Functional block diagram of tire side transceiver Functional block diagram of the tire pressure monitoring system of the second embodiment Functional block diagram of the tire pressure monitoring system of the third embodiment Functional block diagram of the tire pressure monitoring system of the fourth embodiment Functional block diagram of the tire pressure monitoring system of the fifth embodiment Functional block diagram of the tire pressure monitoring system of the sixth embodiment The figure explaining the installation position of the transmission antenna which a vehicle body side transmission / reception apparatus has

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Tire 3 Wheel 4 Tire internal space 10 Tire side transmission / reception apparatus 12 Control circuit part (tire side control means)
14 Transmitting antenna (tire transmitting means)
16 Receiving antenna (tire side receiving means)
17 Sensor part (Air pressure measurement means)
21 Receiving antenna (vehicle body side receiving means)
22 Transmitting antenna (vehicle body side transmitting means)
25 ECU (electronic control unit, vehicle body side control means)
35 Storage unit (vehicle body side storage means)
55 Car body side transceiver

Claims (5)

A plurality of tire-side transmitting / receiving devices respectively installed in a plurality of tire inner spaces formed by a plurality of tires and a plurality of wheels provided in the vehicle; and a vehicle-body-side transmitting / receiving device installed on the vehicle body side of the vehicle Prepared,
Each of the tire side transmission / reception devices transmits to the outside an air pressure measurement means for measuring the air pressure in the tire inner space, unique identification information given to each tire side transmission / reception device, and measurement result information by the air pressure measurement means. Tire-side transmission means, tire-side reception means for receiving a transmission request for the identification information and measurement result information from the outside, and when the tire-side reception means receives the transmission request, the tire-side transmission means Tire-side control means for performing information transmission processing for transmitting the identification information and the measurement result information to the outside,
The vehicle body side transmission / reception device includes a plurality of vehicle body side reception means for receiving the identification information and the measurement result information transmitted from the tire side transmission / reception device, and a plurality of transmission requests transmitted to the tire side transmission / reception device. Vehicle body side transmission means, vehicle body side control means for performing the information reception processing of the identification information and the measurement result information by the vehicle body side reception means, and the request transmission processing of the transmission request by the vehicle body side transmission means. A tire pressure monitoring system,
The vehicle body side transmission means is divided into a plurality of groups consisting of at least one vehicle body side transmission means that is less than the number of the tire side transmission / reception devices, and performs the request transmission processing in units of the group,
The vehicle body side receiving means is divided into a plurality of groups consisting of at least one vehicle body side receiving means less than the number of the tire side transmitting / receiving apparatuses, and the identification information transmitted from the tire side transmitting / receiving apparatus in units of the groups. And receiving the measurement result information,
The number t of the tire side transmitting / receiving devices is (2 ^m −1) × (2 ⁿ −1) ≧ t, ^where m is the number of groups of the vehicle body side transmitting means and n is the number of groups of the vehicle body side receiving means. Satisfy the relationship,
The tire-side transmission / reception device is capable of receiving the transmission request from the vehicle body-side transmission means of any group among the plurality of groups of the vehicle body-side transmission means,
The identification information and the measurement result information transmitted from the tire-side transmitting / receiving device can be received by the vehicle-body-side receiving unit of any group among a plurality of groups of the vehicle-body-side receiving unit,
Furthermore, a group of the vehicle body-side transmitting means each tire side transceiver device transmits receivable the transmission request, the identification information and the measurement result information can be received a the vehicle body is transmitted from each tire side transceiver device A tire pressure monitoring system, wherein a combination of groups of the side receiving means is different for each tire transmitting / receiving device.   The tire pressure monitoring system according to claim 1, wherein the number of groups of the vehicle body side transmission means is 2, the number of groups of the vehicle body side reception means is 2, and the number of tire side transmission / reception devices is 4. The transmission request transmitted by one group of the vehicle body side transmission means is received by the two tire side transmission / reception devices provided on the right wheel side of the vehicle among the plurality of tire side transmission / reception devices, and the vehicle body The transmission request transmitted by the other group of the side transmission means is received by the two tire side transmission / reception devices provided on the left wheel side of the vehicle among the plurality of tire side transmission / reception devices,
The identification information and the measurement result information received by one group of the vehicle body side receiving means are transmitted from two tire side transmitting / receiving devices provided on the front wheel side of the vehicle among the plurality of tire side transmitting / receiving devices. The identification information and the measurement result information received by the other group of the vehicle body side receiving means are the two tire side transmission / reception units provided on the rear wheel side of the vehicle among the plurality of tire side transmission / reception devices. The tire pressure monitoring system according to claim 2, wherein the tire pressure monitoring system is configured to be transmitted from the apparatus. One group of the vehicle body side transmission means is arranged on the right side of the outermost metal plate constituting the right side door of the vehicle,
The tire pressure monitoring system according to claim 3, wherein the other group of the vehicle body side transmission means is arranged on the left side of the outermost metal plate constituting the left side door of the vehicle.   The vehicle body side transmitting means, the vehicle body side receiving means, and the vehicle body side control means of the vehicle body side transmitting / receiving device use a wireless key to unlock and lock the side door of the vehicle. The tire pressure monitor according to claim 3 or 4, wherein the tire pressure monitor is configured to be used both as a transmission antenna, a reception antenna, and a control circuit unit that processes signals transmitted and received between the transmission antenna and the reception antenna. system.

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