JP2023075446A - Tire air pressure monitoring system - Google Patents

Abstract

To easily activate an intended detector by outputting an activation signal from an initiator and make an unintended detector difficult to be activated.SOLUTION: A tire air pressure monitoring system comprises: a rear left side initiator (61) which is arranged on a vehicle body side and has a transmission antenna (L1) that transmits an LF signal; a rear left side detectors (31a, 31b) which are arranged in a double tire (21) on the rear left side and has a reception antenna (L2) that receives the LF signal; and rear right side detectors (32a, 32b) which are arranged in a double tire (22) on the rear right side and has a reception antenna (L2) that receives the LF signal. The initiator (61) on the rear left side is arranged in a region on the front side of the double tire (21) on the rear left side. A transmission axis of the transmission antenna (L1) is orthogonal to the left-right direction of the vehicle. A reception axis of the reception antenna (L2) is orthogonal to the rotational axis direction of each tire.SELECTED DRAWING: Figure 5

Description

FIELD OF THE DISCLOSURE The present disclosure relates to a system for monitoring tire pressure with detectors installed in tires mounted on a vehicle.

Conventionally, there is a direct system as one of systems (TPMS: Tire Pressure Monitoring System) for monitoring the air pressure of tires. In this type of TPMS, a detector provided with a sensor such as a pressure sensor is installed directly on the side of the wheel on which the tire is attached. In addition, the vehicle body is equipped with an antenna and a receiver. When the sensor detection signal is transmitted from the wheel side detector, the detection signal is received by the receiver via the antenna, and the tire pressure is measured. Surveillance takes place.

Among such direct-type TPMS, there is a type in which an initiator is provided on the vehicle body for activating the detector placed on each tire, and the detector is activated by a command signal transmitted from the initiator (for example, See JP-A-2011-183872).

JP 2011-183872 A

When activating a detector installed on a tire with an activation signal sent from an initiator, when the initiator outputs the activation signal targeting a detector close to the initiator, the intended detector close to the initiator is activated. However, unintended detectors may also be activated.

The present disclosure has been made to solve the above-described problems, and the object thereof is to facilitate activation of intended detectors and to activate unintended detectors by outputting activation signals from initiators. to make it difficult.

A tire pressure monitoring system according to one aspect of the present disclosure is a tire pressure monitoring system for monitoring tire pressure of a vehicle, the tire pressure monitoring system includes a first initiator disposed on a vehicle body and having a first transmitting antenna for transmitting a command signal; It is arranged on a first tire of a vehicle, has a first receiving antenna for receiving a command signal, and is activated when the first receiving antenna receives the command signal to output information indicating the air pressure of the first tire. A first detector and a second receiving antenna located at a second tire of the vehicle for receiving the command signal, wherein the pressure of the second tire is activated when the second receiving antenna receives the command signal. and a second detector that outputs information indicating the. The first tire and the second tire are arranged with a predetermined gap in the lateral direction of the vehicle. The first initiator is arranged at a position closer to the first tire than the second tire. The transmission axis of the first transmission antenna is orthogonal to the left-right direction of the vehicle. The receiving axis of the first receiving antenna is orthogonal to the rotation axis direction of the first tire. The receiving axis of the second receiving antenna is perpendicular to the rotation axis direction of the second tire.

According to the above aspect, since the transmission axis of the first transmitting antenna is orthogonal to the left-right direction of the vehicle, the command signal transmitted from the first initiator is difficult to be transmitted in the left-right direction of the vehicle and is orthogonal to the left-right direction of the vehicle. It becomes easier to transmit in the direction of Furthermore, since the receiving axis of the first receiving antenna is orthogonal to the rotational axis direction of the first tire and the receiving axis of the second receiving antenna is orthogonal to the rotational axis direction of the second tire, the first detector and the second detector , it is difficult to receive the command signal from the left and right direction of the vehicle, and it becomes easy to receive the command signal from the direction orthogonal to the left and right direction of the vehicle. Since the first initiator is arranged closer to the first tire than the second tire, the transmission axis of the first transmitting antenna is brought closer to the receiving axis of the first receiving antenna than the receiving axis of the second receiving antenna. can be done. Thus, by transmitting a command signal from the first initiator, it is easier to activate the first detector located on the first tire closer to the first initiator, and located on the second tire farther from the first initiator. The second detector can be made difficult to activate. As a result, by outputting the command signal from the first initiator, the intended first detector can be easily activated, and the unintended second detector can be hard to activate.

According to the present disclosure, by outputting the activation signal from the initiator, it is possible to facilitate the activation of the intended detector and make it difficult to activate the unintended detector.

It is a figure which shows the structure of a vehicle typically. It is a block diagram which shows an example of a structure of a detector. It is the side view which looked at the vehicle from the left side. It is a perspective view which shows the state where the detector was attached to each tire. FIG. 4 is a diagram schematically showing an example of a placement area of detectors that can be activated by a rear left initiator;

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a diagram schematically showing the configuration of a vehicle 10 to which a tire pressure monitoring system (TPMS) according to this embodiment is applied. Vehicle 10 according to the present embodiment is a vehicle that has single tires on the front wheels that are steered and double tires on the rear wheels that are not steered. A single tire is a form in which one tire is mounted at one tire mounting position. A double tire is a form in which two tires of the same size connected to each other are mounted at one tire mounting position. Double tires are mainly used for large vehicles such as trucks and buses.

Specifically, the vehicle 10 includes front tires 11 and 12 and rear double tires 21 and 22 . FIG. 1 illustrates a case where the vehicle 10 is a rear-wheel drive system. The rear double tires 21 and 22 are attached to the rear left axle R1 and the rear right axle R2, respectively. The driving system of the vehicle 10 is not limited to the rear-wheel drive system, and may be a front-wheel drive system or an all-wheel drive system.

The double tire 21 includes a tire 21a on the inner side of the vehicle and a tire 21b on the outer side of the vehicle. The double tire 22 includes a tire 22a on the inner side of the vehicle and a tire 22b on the outer side of the vehicle.

Additionally, the vehicle 10 is equipped with a tire pressure monitoring system (TPMS). Specifically, the vehicle 10 includes a plurality of detectors 13 , 14 , 31 a - 32 b each detecting tire pressure, and a TPMS receiver 40 .

Detectors 13 and 14 are installed on front tires 11 and 12, respectively. The detectors 31a-32b are installed on the rear tires 21a-22b, respectively. Each detector 13, 14, 31a-32b may be formed integrally with a valve for sucking air into each tire, for example.

The front tires 11 and 12 and the rear tires 21a to 22b have the same specification and configuration so that tire rotation can be performed. Therefore, the detectors 13, 14, 31a-32b have the same configuration. In the following description, the detectors 13, 14, 31a-32b are also referred to as "detector 30" without distinguishing between them, unless it is necessary to distinguish between them.

Each detector 30 is activated when a predetermined activation condition is satisfied, detects the air pressure of each tire, and includes a detection result in a UHF (Ultra High Frequency) band radio signal (hereinafter simply referred to as "UHF signal"). ). It should be noted that the "predetermined activation condition" is set in advance so as to be satisfied regularly or irregularly. Thereby, each detector 30 can be activated intermittently at mutually different timings.

The UHF signal output by each detector 30 includes at least information indicating a unique ID number for identifying each detector 30 in addition to information indicating tire pressure. By receiving the UHF signal output from each detector 30, the TPMS receiver 40 can monitor the air pressure of each tire.

The TPMS receiver 40 is arranged on the vehicle body side of the vehicle 10 . The TPMS receiver 40 comprises a receiving antenna A1 and a monitoring unit 45. FIG. The receiving antenna A1 is configured to be able to receive UHF signals transmitted from each detector 30 .

The monitoring unit 45 monitors the air pressure of each tire based on the UHF signal received by the receiving antenna A1. The monitoring unit 45 includes a storage section 46 and a processing section 47 .

The processing unit 47 includes a processor such as a CPU (Central Processing Unit) (not shown), a memory, and an input/output buffer. The memory includes ROM (Read Only Memory) and RAM (Random Access Memory). The processor expands a program stored in ROM into RAM and executes it. Various processes executed by the processing unit 47 are described in the programs stored in the ROM.

Information indicating the tire position where each detector 30 is arranged, information indicating tire air pressure, etc. are stored in the storage unit 46 in association with the ID number of each detector 30 . In the present embodiment, a total of six tire positions (front left, front right, rear left inside, rear left outside, rear right inside, rear right outside) are set in advance. is associated with any tire position. For example, the ID number of the detector 13 is associated with the tire position "front left", and the ID number of the detector 32b is associated with the tire position "rear right outside".

When the UHF signal is received from each detector 30, the monitoring unit 45 refers to the information stored in the storage unit 46 to specify the tire position of the ID number included in the UHF signal, and the specified tire position. is updated with the tire pressure contained in the UHF signal. For example, when the monitoring unit 45 receives a UHF signal containing the ID number of the detector 32a, the monitoring unit 45 refers to the corresponding relationship between the ID number and the tire position stored in the storage unit 46 to obtain the information contained in the UHF signal. The tire position corresponding to the ID number is identified as "rear right inner", and the air pressure of the identified "rear right inner" is updated with the tire air pressure included in the UHF signal.

The TPMS receiver 40 can cause the display unit 60 to display the information on the correspondence relationship between tire positions and tire pressures stored in the storage unit 46 . The display unit 60 is arranged at a position that can be visually recognized by the driver. The display unit 60 is arranged, for example, on an in-vehicle instrument panel.

If the tire pressure included in the received UHF signal is equal to or less than the low pressure threshold, the monitoring unit 45 causes the display unit 60 to display a warning and the tire position where the tire pressure is equal to or less than the low pressure threshold. The TPMS receiver 40 performs this tire air pressure determination process for each received UHF signal, and monitors the air pressure of each tire. This allows the driver to recognize in real time the position of the tire that has fallen below the low pressure threshold.

Further, vehicle 10 according to the present embodiment is provided with initiators 51 , 52 , 61 , 62 for starting each detector 30 . Each initiator 51 , 52 , 61 , 62 is electrically connected to the TPMS receiver 40 .

The initiator 51 is arranged in a region located in the radial direction of rotation of the front left tire 11 (a region behind the tire 11 in the example shown in FIG. 1) and used to activate the detector 13 . The initiator 52 is arranged in a region located in the radial direction of rotation of the tire 12 on the front right side (the region behind the tire 12 in the example shown in FIG. 1) and used to activate the detector 14 .

The initiator 61 is arranged in a region located in the radial direction of rotation of the rear left double tire 21 (a region in front of the double tire 21 in the example shown in FIG. 1), and is used to activate the detectors 31a and 31b. The initiator 62 is arranged in a region located in the radial direction of rotation of the right rear double tire 22 (a region in front of the double tire 22 in the example shown in FIG. 1), and is used to activate the detectors 32a and 32b.

Each initiator 51, 52, 61, 62 has the same configuration. In the following description, the initiators 51, 52, 61, and 62 are also referred to as the "initiator 50" without distinguishing between them when the initiators 51, 52, 61, and 62 need not be distinguished.

Each initiator 50 has a transmission antenna L1, and is configured to be able to output a radio wave signal in a long-wave (Low Frequency) band (hereinafter also simply referred to as "command signal" or "LF signal") from the transmission antenna L1. Each initiator 50 transmits an LF signal (command signal) to each detector 30 based on a command from the monitoring unit 45 .

The transmitting antenna L1 is an antenna (for example, a coil antenna) having directivity in which the radio wave output intensity in the transmission axis direction along a specific direction is higher than the radio wave output intensity along the direction intersecting the transmission axis direction. In the present embodiment, the transmission axis of the transmission antenna L1 of each initiator 50 is set along a direction perpendicular to the left-right direction of the vehicle 10 (the front-rear direction of the vehicle 10 in the example shown in FIG. 1).

<Configuration of detector 30>
FIG. 2 is a block diagram showing an example of the configuration of the detector 30. As shown in FIG. The detector 30 includes a controller 35, a pressure sensor 38, an acceleration sensor (G sensor) 39, a receiving antenna L2, a receiving circuit CR, a transmitting antenna A2, and a transmitting circuit CT.

The controller 35 includes a storage section 36 and a processing section 37 . The processing unit 37 includes a processor such as a CPU (not shown), a memory, and an input/output buffer. The memory includes ROM and RAM. The processor expands a program stored in ROM into RAM and executes it. Programs stored in the ROM describe various processes to be executed by the processing unit 37 .

A unique ID number is stored in the storage unit 36 for each detector 30 shown in FIG. For example, the storage unit 36 included in the detector 13 arranged on the front left tire 11 stores "01" as the ID number. Further, "02" is stored as an ID number in the storage unit 36 included in the detector 14 arranged on the right front tire 12 in FIG. In this manner, the ID number unique to each detector 30 is stored in the storage section 36 in each detector 30 .

The pressure sensor 38 detects tire air pressure and outputs the detection result to the controller 35 . The acceleration sensor 39 detects acceleration acting on the detector 30 and outputs the detection result to the controller 35 . In addition to pressure sensor 38 and acceleration sensor 39, detector 30 may further include a temperature sensor for detecting tire temperature.

The receiving antenna L2 receives the LF signal transmitted from the initiator 50 . The LF signal received by the receiving antenna L2 is sent to the controller 35 via the receiving circuit CR. By receiving the LF signal from the receiving circuit CR, the controller 35 can recognize the information contained in the LF signal and the received signal strength indicator (RSSI) of the LF signal.

The receiving antenna L2 is an antenna (for example, a coil antenna) having directivity in which the radio wave receiving sensitivity in the receiving axial direction along a specific direction is higher than the radio wave receiving sensitivity along the direction intersecting the receiving axial direction. In the present embodiment, the receiving axis of the receiving antenna L2 of each detector 30 is in a direction orthogonal to the left-right direction of the vehicle 10, that is, a direction orthogonal to the rotation axis direction of each tire (in the example shown in FIG. 4 described later, Circumferential direction of the tire).

The controller 35 controls the transmission circuit CT to output the UHF signal from the transmission antenna A2. The UHF signal includes information indicating the ID number stored in the storage unit 36, the tire air pressure detected by the pressure sensor 38, and the acceleration detected by the acceleration sensor 39.

As described above, the detector 30 is activated and outputs a UHF signal at the timing when a predetermined activation condition is satisfied. The detector 30 is equipped with a battery (not shown) and operates on electric power supplied from the battery. However, since this battery cannot be easily charged from the outside, the operating time of the detector 30 is minimized for detection. It is desirable to reduce the power consumption of the device 30 . From this point of view, the activation condition of the detector 30 is set in advance so as to minimize the activation frequency of the detector 30 . For example, the activation condition of the detector 30 includes a timer activation condition that a timer (not shown) measures that a predetermined timer time has elapsed since the previous stop, and the acceleration detected by the acceleration sensor 39 is a specific value (for example, (maximum value or minimum value).

Furthermore, in the present embodiment, the initiator activation condition that the detector 30 has received the LF signal from the initiator 50 is also included in the activation conditions for the detector 30 . Since a small amount of power is consumed by the detector 30 even during a period when the detector 30 waits for reception of the LF signal (hereinafter also referred to as a "standby period"), from the viewpoint of suppressing the power consumption of the detector 30, detection The standby period of the device 30 is intermittently set. For example, the standby period may be set in a relatively long period (for example, about several minutes), and one standby period may be limited to a relatively short period of time (for example, about several milliseconds).

Each detector 30 is activated when it receives an LF signal from the initiator 50 and outputs a UHF signal containing information indicating the tire pressure.

<Transmission axial direction of transmission antenna L1 of initiator 50>
FIG. 3 is a side view of the vehicle 10 viewed from the left side. Initiators 51 and 52 are arranged in a region behind front tires 11 and 12 . The initiators 61 and 62 are arranged in front regions of the rear double tires 21 and 22 .

In the present embodiment, the transmission axis of transmission antenna L<b>1 of each initiator 50 is set along the longitudinal direction of vehicle 10 . Note that the transmission axis of the transmission antenna L1 may be set along a direction orthogonal to the left-right direction of the vehicle 10, and is not necessarily set along the front-rear direction of the vehicle 10. For example, the transmission axis of transmission antenna L<b>1 may be set along the vertical direction of vehicle 10 .

In the present embodiment, front initiators 51 and 52 are arranged at positions sufficiently separated from rear double tires 21 and 22 along the longitudinal direction of vehicle 10 . The output intensity of the LF signal from the initiators 51 and 52 is set to an intensity that does not reach the rear double tires 21 and 22 . As a result, even if the front initiators 51 and 52 output the LF signal, the detectors 30 arranged on the rear double tires 21 and 22 are not activated.

Similarly, the rear initiators 61 and 62 are arranged at positions sufficiently separated from the front tires 11 and 12 along the longitudinal direction of the vehicle 10 . The output intensity of the LF signal from the initiators 61 and 62 is set to an intensity that does not reach the front tires 11 and 12 . Accordingly, even if the LF signal is output from the rear initiators 61 and 62, the detectors 30 arranged on the front tires 11 and 12 are not activated.

<Receiving axial direction of receiving antenna L2 of detector 30>
FIG. 4 is a perspective view showing the detector 30 attached to each tire. In this embodiment, the detector 30 is fixed to the wheel portion WH of the tire. Further, the detectors 30 are fixed to the wheel portion WH so that the receiving axis of the receiving antenna L2 of each detector 30 is aligned with the circumferential direction of tire rotation. Accordingly, the receiving axis of the receiving antenna L2 of each detector 30 is set to be perpendicular to the left-right direction of the vehicle 10 when each tire is mounted on the vehicle 10 .

The receiving axis of the receiving antenna L2 may be set along the direction perpendicular to the rotation axis direction of each tire, and is not necessarily set along the rotation circumferential direction of each tire. For example, the receiving axis of the receiving antenna L2 may be set along the radial direction of rotation of each tire.

<Activation of Detector 30 by Initiator 50>
In the tire pressure monitoring system having the configuration described above, the front initiators 51 and 52 are positioned sufficiently far from the rear double tires 21 and 22, and the LF signals are sent from the initiators 51 and 52. Even if it is output, the detector 30 arranged on the rear tire is not activated. Similarly, the rear initiators 61 and 62 are arranged at positions sufficiently distant from the front tires 11 and 12, so that even if the LF signals are output from the initiators 61 and 62, they are not arranged on the front tires. Detector 30 is not activated.

On the other hand, the distance between the front initiators 51 and 52 arranged side by side in the left-right direction of the vehicle 10 can be only about the width of the vehicle 10 at maximum. Therefore, for example, when an LF signal is output from the initiator 51 for activating the front left detector 13, not only the intended front left detector 13 but also the unintended front right detector 14 is activated. It may get lost.

Similarly, the distance between the rear initiators 61 and 62 that are arranged side by side in the left-right direction of the vehicle 10 can be only about the width of the vehicle 10 at maximum. Therefore, for example, when an LF signal is output from the initiator 61 for activating the rear left detectors 31a and 31b, not only the intended rear left detectors 31a and 31b but also the unintended rear right detector 32a , 32b may also start up.

As a countermeasure, in the tire pressure monitoring system according to the present embodiment, the transmission axis of the transmission antenna L1 of each initiator 50 is set along the front-rear direction of the vehicle 10 (the direction perpendicular to the left-right direction of the vehicle 10). In addition, the receiving axis of the receiving antenna L2 of each detector 30 is set in a direction orthogonal to the rotation axis direction of each tire (a direction orthogonal to the left-right direction of the vehicle 10). As a result, when the LF signal is output from each initiator 50, it is possible to easily activate the intended detector 30 and to make it difficult to activate the unintended detector 30. FIG.

FIG. 5 is a diagram schematically showing an example of the arrangement area AR1 of the detectors 30 that can be activated by the initiator 61 on the rear left side. As described above, since the transmission axis of the transmission antenna L1 of the initiator 61 is set along the longitudinal direction of the vehicle 10, the LF signal transmitted from the initiator 61 is difficult to transmit in the lateral direction of the vehicle 10. This facilitates transmission in the longitudinal direction of the vehicle 10 . Furthermore, since the receiving axes of the receiving antennas L2 of the detectors 31a and 31b are set along the direction perpendicular to the rotation axis direction of the double tires 21 (that is, the longitudinal direction of the vehicle 10), the detectors 31a and 31b are , LF signals from the left and right directions of the vehicle 10 are difficult to receive, and LF signals from the front and rear directions of the vehicle 10 are easily received. Since the initiator 61 is arranged in the area in front of the rear left double tire 21, the transmission axis of the transmission antenna L1 of the left initiator 61 is positioned rearward from the transmission axis of the transmission antenna L1 of the right initiator 62. It can be brought close to the receiving axis of the receiving antenna L2 of the left detectors 31a and 31b.

Accordingly, the arrangement area AR1 of the detector 30 that can be activated by the initiator 61 on the left rear includes the left rear detectors 31a and 31b and does not include the right rear detectors 32a and 32b. That is, by transmitting the LF signal from the initiator 61, the detectors 31a and 31b arranged on the left side double tire 21 closer to the initiator 61 can be easily activated, and the detectors 31a and 31b arranged on the right side double tire 22 farther from the initiator 61 can be activated. It is possible to make it difficult to start the detectors 32a and 32b. As a result, by outputting the LF signal from the initiator 61, it is possible to easily activate the intended left detectors 31a and 31b and to make it difficult to activate the unintended right detectors 32a and 32b.

When the rear right detectors 32a and 32b are activated, when the front left detector 13 is activated, when the front right detector 14 is activated, and when the rear left detectors 31a and 31b are activated is similar to

For example, when activating the front right detector 14 , the monitoring unit 45 causes the front right initiator 52 to transmit an activation signal. Since the transmission axis of the transmission antenna L1 of the initiator 52 is set along the front-rear direction of the vehicle 10, the LF signal transmitted from the initiator 52 is difficult to be transmitted in the left-right direction of the vehicle 10. easier to communicate to Furthermore, since the receiving axis of the receiving antenna L2 of the detector 14 on the front right side is set along the direction perpendicular to the rotation axis direction of the tire 12 (that is, the longitudinal direction of the vehicle 10), the detector 14 It is difficult to receive LF signals from the left and right directions of the vehicle 10, and it becomes easy to receive LF signals from the front and rear directions of the vehicle 10. - 特許庁Since the initiator 52 is arranged in the area behind the tire 14 on the right front side, the transmission axis of the transmission antenna L1 of the initiator 52 is set to the detector on the right side of the transmission axis of the transmission antenna L1 of the left initiator 51. 14 can be brought close to the receiving axis of the receiving antenna L2. As a result, by outputting the LF signal from the initiator 52 on the front right side, it is possible to easily activate the intended detector 14 on the right front side and to make it difficult to activate the unintended detector 13 on the left front side.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

The exemplary embodiments and modifications thereof described above are specific examples of the following aspects.
(1) A tire pressure monitoring system according to the present disclosure is a tire pressure monitoring system for monitoring tire pressure of a vehicle, the tire pressure monitoring system including a first initiator disposed on a vehicle body and having a first transmitting antenna for transmitting a command signal; It is arranged on a first tire of a vehicle, has a first receiving antenna for receiving a command signal, and is activated when the first receiving antenna receives the command signal to output information indicating the air pressure of the first tire. A first detector and a second receiving antenna located on a second tire of the vehicle for receiving the command signal, wherein the pressure of the second tire is activated when the second receiving antenna receives the command signal. and a second detector that outputs information indicating the. The first tire and the second tire are arranged with a predetermined gap in the lateral direction of the vehicle. The first initiator is arranged at a position closer to the first tire than the second tire. The transmission axis of the first transmission antenna is orthogonal to the left-right direction of the vehicle. The receiving axis of the first receiving antenna is orthogonal to the rotation axis direction of the first tire. The receiving axis of the second receiving antenna is perpendicular to the rotation axis direction of the second tire.

According to the above aspect, since the transmission axis of the first transmitting antenna is orthogonal to the left-right direction of the vehicle, the command signal transmitted from the first initiator is difficult to be transmitted in the left-right direction of the vehicle and is orthogonal to the left-right direction of the vehicle. It becomes easier to transmit in the direction of Furthermore, since the receiving axis of the first receiving antenna is orthogonal to the rotational axis direction of the first tire and the receiving axis of the second receiving antenna is orthogonal to the rotational axis direction of the second tire, the first detector and the second detector , it is difficult to receive the command signal from the left and right direction of the vehicle, and it becomes easy to receive the command signal from the direction orthogonal to the left and right direction of the vehicle. Since the first initiator is arranged closer to the first tire than the second tire, the transmission axis of the first transmitting antenna is brought closer to the receiving axis of the first receiving antenna than the receiving axis of the second receiving antenna. can be done. Thus, by transmitting a command signal from the first initiator, it is easier to activate the first detector located on the first tire closer to the first initiator, and located on the second tire farther from the first initiator. The second detector can be made difficult to activate. As a result, by outputting the command signal from the first initiator, the intended first detector can be easily activated, and the unintended second detector can be hard to activate.

(2) In one aspect, the first initiator is arranged in a region in the radial direction of rotation of the first tire.

According to the above aspect, the first transmitting antenna and the first receiving antenna are arranged so as to line up in the direction orthogonal to the left-right direction of the vehicle. Therefore, the command signal transmitted from the first initiator can be easily transmitted by the first initiator.

(3) In one aspect, the vehicle further includes a second initiator arranged at a position closer to the second tire than the first tire and having a second transmitting antenna for transmitting the command signal. The transmission axis of the second transmitting antenna is orthogonal to the left-right direction of the vehicle.

According to the above aspect, by transmitting the command signal from the second initiator, it becomes easier to activate the second detector closer to the second initiator, and the first detector located on the first tire away from the second initiator. It can make it difficult to activate the device.

(4) In one aspect, the second initiator is arranged in a region in the radial direction of rotation of the second tire.

According to the above aspect, the second transmitting antenna and the second receiving antenna are arranged so as to line up in the direction perpendicular to the left-right direction of the vehicle. Therefore, the command signal transmitted from the second initiator can be easily transmitted by the second initiator.

(5) In one aspect, the command signal is a radio signal having a long waveband.
According to the above aspect, it is possible to activate the first detector or the second detector with a radio signal having a long waveband.

10 vehicle, 11, 12, 21a-22b tire, 13, 14, 31a-32b detector, 21, 22 double tire, 35 controller, 36, 46 storage unit, 37, 47 processing unit, 38 pressure sensor, 39 acceleration sensor , 40 TPMS receiver, 45 monitoring unit, 51, 52, 61, 62 initiator, 60 display unit, A1, L2 receiving antenna, A2, L1 transmitting antenna, CR receiving circuit, CT transmitting circuit, R1, R2 axle, WH wheel Department.

Claims (5)

A tire pressure monitoring system for monitoring tire pressure of a vehicle, comprising:
a first initiator disposed on the vehicle body of the vehicle and having a first transmitting antenna for transmitting a command signal;
a first receiving antenna disposed on a first tire of the vehicle for receiving the command signal, and activated to increase the air pressure of the first tire when the first receiving antenna receives the command signal; A first detector that outputs information indicating
a second receiving antenna disposed on a second tire of the vehicle for receiving the command signal; activated when the second receiving antenna receives the command signal to increase the air pressure of the second tire; A second detector that outputs information indicating
The first tire and the second tire are arranged at a predetermined interval in the left-right direction of the vehicle,
The first initiator is arranged at a position closer to the first tire than the second tire,
A transmission axis of the first transmission antenna is perpendicular to the left-right direction of the vehicle,
the receiving axis of the first receiving antenna is perpendicular to the rotation axis direction of the first tire,
The tire air pressure monitoring system, wherein the receiving axis of the second receiving antenna is perpendicular to the rotation axis direction of the second tire. The tire pressure monitoring system according to claim 1, wherein the first initiator is arranged in a region located in the radial direction of rotation of the first tire. Further comprising a second initiator arranged at a position closer to the second tire than the first tire and having a second transmitting antenna for transmitting the command signal;
3. The tire pressure monitoring system according to claim 2, wherein a transmission axis of said second transmission antenna is perpendicular to the lateral direction of said vehicle. 4. The tire pressure monitoring system according to claim 3, wherein said second initiator is arranged in a region located in the radial direction of rotation of said second tire. The tire pressure monitoring system according to any one of claims 1 to 4, wherein said command signal is a radio wave signal having a long wave band.

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