JP2023067754A - Tire position determination system and rotating body position determination system - Google Patents

Abstract

To identify a tire mounted on an axle, using a detector attached to each of the axle and the tire.SOLUTION: A tire position determination system comprises a first tire detector, a rotating body detector and a monitoring unit. The first tire detector is attached to a first tire to detect acceleration. The rotating body detector is attached to a first rotating body to detect acceleration. The monitoring unit obtains a first correspondence relation showing a relation between a first value and a second value in a first period of time, obtains a second correspondence relation showing a relation between a third value and a fourth value in a second period of time, and compares the first correspondence relation with the second correspondence relation, so as to determine whether the first tire rotates in synchronization with the first rotating body or not.SELECTED DRAWING: Figure 19

Description

The present disclosure relates to a tire position determination system and a rotating body position determination system.

Conventionally, in a system (TPMS: Tire Pressure Monitoring System) for monitoring tire pressure in a vehicle, a detector is attached to each of a plurality of tires. A detector attached to each of the plurality of tires transmits air pressure information to a processing device such as an ECU attached to the vehicle body.

Some of such TPMS have an autolocation function that automatically determines to which of a plurality of tires a detector is attached.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2019-048547) discloses a tire condition information detection system that determines to which tire a detector is attached among double tires used in a truck or the like. . In the tire condition information detection system of Patent Document 1, each detector detects the acceleration of the tire in the circumferential direction of rotation, thereby realizing an autolocation function.

JP 2019-048547 A

Generally, however, tire rotation is performed between tires mounted on different axles, as well as between the inside and outside of double tires mounted on the same axle. Even if tires are rotated between tires mounted on different axles, it is desirable to automatically determine which tire the detector is mounted on using the autolocation function. .

The present disclosure has been made to solve the above-mentioned problems, and the purpose thereof is to detect the attached tire with respect to the axle using detectors attached to each of the axle and the tire. to specify.

A tire position determination system according to an aspect of the present disclosure is a tire position determination system provided in a vehicle including a first rotating body that rotates in synchronization with any one of a plurality of tires including a first tire. The tire position determination system includes a first tire detector, a rotating body detector, and a monitoring unit. The first tire detector is attached to the first tire and detects acceleration in a direction intersecting with the rotation axis direction of the first tire. The rotating body detector is attached to the first rotating body and detects acceleration in a direction intersecting with the rotation axis direction of the first rotating body. The monitoring unit is configured to receive information from the first tire detector and the rotating body detector. The monitoring unit acquires a first correspondence relationship indicating a relationship between a first value based on the detection value of the first tire detector and a second value based on the detection value of the rotating body detector in the first period; Acquiring a second correspondence indicating a relationship between a third value based on the detection value of the first tire detector and a fourth value based on the detection value of the rotating body detector in the period, and acquiring the first correspondence and the second correspondence The result of the comparison with the relationship is used to determine whether the first tire rotates in synchronism with the first rotating body.

According to the above aspect, it is determined whether or not the correspondence relationship between the rotation angle of the rotating body and the rotation angle of the first tire in the first period has changed in the second period. Thereby, it is possible to determine whether or not the first tire rotates in synchronization with the first rotating body, and to determine the tire attached to the rotating body.

A rotating body position determination system according to an aspect of the present disclosure is a rotating body position determination system provided in a vehicle including a third rotating body and a fourth rotating body that rotate in synchronization with any one of a plurality of tires. be. The rotating body position determination system includes: a third rotating body detector attached to the third rotating body and detecting acceleration in a direction intersecting the rotation axis direction of the third rotating body; a fourth rotating body detector for detecting acceleration in a direction intersecting with the rotation axis direction of the rotating body; and a monitoring unit configured to receive information from the third rotating body detector and the fourth rotating body detector. Prepare. The monitoring unit determines the mounting position of the third rotating body detector based on the identifier received from the third rotating body detector, and calculates a first value based on the detection value of the third rotating body detector in the first period, and Obtaining a first correspondence relationship indicating a relationship between a value detected by a fourth body of rotation detector and a second value based on the value detected by the fourth body of rotation detector, and obtaining a third value based on a value detected by the body of rotation detector 3 and a fourth rotation in the second period A second correspondence indicating a relationship with a fourth value based on the detection value of the body detector is obtained, and the result of comparing the first correspondence and the second correspondence is used to determine the third rotation and the fourth rotation. Determines whether or not the body rotates in synchronism with the body.

According to the above aspect, it is determined whether or not the correspondence relationship between the rotation angle of the third rotor and the rotation angle of the fourth rotor in the first period changes in the second period. Accordingly, it is possible to determine whether or not the third rotating body rotates in synchronization with the fourth rotating body, and to detect the position of the fourth rotating body based on the identifier received from the third rotating body.

According to the present disclosure, it is possible to identify a tire mounted relative to an axle and determine the position of the tire.

1 is a diagram schematically showing the configuration of a vehicle 10 to which a tire position determination system according to this embodiment is applied; FIG. It is a block diagram which shows the structure of a tire detector. It is an exploded perspective view of a double tire. It is an external perspective view of the tire detector attached to the wheel WH. FIG. 4 is a transition diagram of the arrangement of tire detectors when the tires on the inside of the vehicle rotate; 1 is an external perspective view of an axle detector attached to an axle; FIG. FIG. 10 is a layout transition diagram of the axle detector when the axle rotates; 8 is a diagram showing the relationship between the arrangement of the acceleration sensors shown in FIGS. 5 and 7 and detected values; FIG. FIG. 10 is a diagram showing the arrangement of the double tire and the axle on the right side of the first rear row when viewed from the positive direction side of the Y axis; FIG. 4 is a diagram showing the arrangement of the double tire and axle on the left side of the first rear row when viewed from the negative direction side of the Y axis; FIG. 10 is a diagram showing the arrangement of the double tire and the axle on the right side of the first rear row when viewed from the positive direction side of the Y-axis during the first stop period; FIG. 10 is a diagram showing the arrangement of the double tire and the axle on the left side of the first rear row when viewed from the negative direction side of the Y-axis in the first stop period; 4 is a table of a storage unit collectively storing UHF signals received from each of a tire detector and an axle detector during a first stop period; 4 is a table showing a correspondence relationship of rotation angles in a first stop period; FIG. 10 is a diagram showing the arrangement of the double tire and the axle on the right side of the first rear row when viewed from the positive direction side of the Y axis during the second stop period; FIG. 10 is a diagram showing the arrangement of the double tire and the axle on the left side of the first rear row when viewed from the negative direction side of the Y-axis during the second stop period; FIG. 11 is a table of a storage unit collectively storing UHF signals received from each of a tire detector and an axle detector during a second stop period; FIG. It is a table which shows the correspondence of the rotation angle in a 2nd stop period. 4 is a flowchart showing tire position determination processing by a monitoring unit; FIG. 10 is a table of a storage unit that stores UHF signals received during a first stop period when axle detectors and tire detectors are attached in advance in a specific arrangement; FIG. FIG. 10 is a table of a storage unit that stores UHF signals received during a second stop period when axle detectors and tire detectors are attached in advance in a specific arrangement; FIG. FIG. 11 is an external perspective view of an axle detector attached to an axle in Modification 2; It is a figure which shows the nut looseness detector attached to a nut. FIG. 4 is a diagram for explaining that a plurality of nut looseness detectors are attached to one axle;

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.

[Embodiment 1]
<Overall composition>
FIG. 1 is a diagram schematically showing the configuration of a vehicle 10 to which a tire position determination system 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 are connected to each other and mounted at one tire mounting position. A direction FR shown in FIG. 1 is the forward direction of the vehicle 10 .

In the following description, the vertical direction when the vehicle 10 is arranged on a plane is defined as the "Z-axis direction", and the direction perpendicular to the Z-axis direction and along the forward direction of the vehicle 10 is defined as the "X-axis direction." The direction perpendicular to the X-axis direction is defined as the "Y-axis direction". Further, hereinafter, the positive direction of the Z-axis in each drawing is referred to as the upper side, the negative direction of the Z-axis is referred to as the lower side, the positive direction of the X-axis is referred to as the front side, the negative direction of the X-axis is referred to as the rear side, and the positive direction of the Y-axis is referred to as the rear side. The direction may be called the right side, and the negative direction of the Y-axis may be called the left side.

Vehicle 10 of the present embodiment includes front axles F1, F2 and tires 11, 12, and rear axles R1-R4 and double tires 21-24. The vehicle 10 employs two-axle double tires for the rear wheels. Double tires are mainly used for large vehicles such as trucks and buses.

FIG. 1 illustrates a case where the vehicle 10 is a rear-wheel drive system. Front tires 11 and 12 are attached to a front left axle F1 and a front right axle F2, respectively. That is, the axle F1 rotates integrally with the tire 11 . Similarly, axle F2 rotates integrally with tire 12 .

The rear double tires 21, 22, 23, and 24 are respectively attached to the left axle R1 of the first rear row, the right axle R2 of the first rear row, the left axle R3 of the second rear row, and the second rear row. It is mounted on axle R4 on the right side of the eye. That is, the axles R1 to R4 rotate integrally with the double tires 21 to 24, 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.

In other words, the axles F1, F2, R1-R4 rotate synchronously with the rotation of the tires attached to each. Below, the axles F1, F2, R1 to R4 are collectively referred to as "axes Ax". The axle Ax may correspond to the "first rotating body" in the present disclosure.

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. The double tire 23 includes a tire 23a on the inner side of the vehicle and a tire 23b on the outer side of the vehicle. The double tire 24 includes a tire 24a on the inner side of the vehicle and a tire 24b on the outer side of the vehicle. Hereinafter, each tire 11, 12, 21a to 24b is collectively referred to as "tire Tr".

Furthermore, the vehicle 10 is equipped with a system (TPMS) for monitoring the air pressure of each tire. Specifically, the vehicle 10 includes a plurality of tire detectors 13, 14, 31a, 31b to 34a, 34b each detecting tire air pressure, and gravity sensors in the radial direction of rotation of axles F1, F2, R1 to R4. A plurality of axle detectors 15a, 15b, 16a, 16b, 17a, 17b for detecting acceleration and a TPMS receiver 40 are provided. Tire detectors 13 and 14 are attached to wheels of front tires 11 and 12, respectively. The tire detectors 31a, 31b-34a, 34b are attached to the wheels of the rear tires 21a-24b, respectively. Note that each tire detector 13, 14, 31a, 31b to 34a, 34b may be formed integrally with a valve for sucking air into each tire.

Axle detectors 15a-17b are attached to axles F1, F2, R1-R4, respectively. Note that the locations where the axle detectors 15a to 17b are attached are not limited to the axles. For example, the axle detectors 15a-17b may be attached to hubs, knuckles, etc. that rotate in synchronism with tire rotation. Axle detectors 15a-17b may correspond to "rotating body detectors" in the present disclosure.

Each of the tire detectors 13, 14, 31a, 31b to 34a, 34b and the axle detectors 15a to 17b is activated when a predetermined activation condition is satisfied, detects the air pressure of each tire, and outputs a UHF signal containing the detection result. (Ultra High Frequency) band radio signals (hereinafter also simply referred to as “UHF signals”). It should be noted that the "predetermined activation condition" is set in advance so as to be satisfied regularly or irregularly. As a result, the tire detectors 13, 14, 31a, 31b-34a, 34b and the axle detectors 15a-17b are intermittently activated at mutually different timings to transmit UHF signals. The radio signals transmitted by the tire detectors 13, 14, 31a, 31b to 34a, 34b and the axle detectors 15a to 17b are not limited to the UHF band, and may be radio signals of other frequencies.

At least each tire detector 13, 14, 31a, 31b to 34a, 34b is specified in the UHF signal output from each of the tire detectors 13, 14, 31a, 31b to 34a, 34b and the axle detectors 15a to 17b. contains information that indicates a unique ID number for The UHF signals output from the tire detectors 13, 14, 31a, 31b to 34a, 34b contain information indicating the tire pressure. The TPMS receiver 40 receives UHF signals output from the tire detectors 13, 14, 31a, 31b to 34a, 34b, thereby monitoring the air pressure of each tire.

The front tires 11 and 12 and the rear tires 21a to 24b have the same specification and configuration so that tire rotation can be performed. Therefore, tire detectors 13, 14, 31a, 31b to 34a, 34b have the same configuration. Hereinafter, when it is not necessary to distinguish between the tire detectors 13, 14, 31a, 31b to 34a, and 34b, the tire detectors 13, 14, 31a, 31b to 34a, and 34b will not be distinguished. Detector 30” is also described. Further, each of the axle detectors 15a to 17b has the same configuration. In the following description, the axle detectors 15a to 17b will also be referred to as "axle detector 15" without distinguishing between them when there is no need to distinguish between them.

The TPMS receiver 40 is provided on the vehicle body side of the vehicle 10 . The TPMS receiver 40 comprises a monitoring unit 45 for monitoring the air pressure of each tire. The monitoring unit 45 includes a storage section 46, a processing section 47, and an antenna A1. Antenna A<b>1 is configured to be able to receive UHF signals transmitted from tire detector 30 and axle detector 15 . A monitoring unit 45 receives the UHF signal received by antenna A1.

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 tire detector 30 is attached and information indicating the tire air pressure are stored in the storage unit 46 in association with the ID number of each tire detector 30 . In this embodiment, a total of 10 tire positions (front left, front right, rear 1st row left inside, rear 1st row left outside, rear 1st row right inside, rear 1st row right outside, rear 2) left inside row, second rear row left outside, second rear row right inside, and second rear row right outside) are set in advance, and the ID number of each tire detector 30 corresponds to one of the tire positions. attached. For example, the ID number of the tire detector 13 is associated with the tire position "front left", and the ID number of the tire detector 32a is associated with the tire position "rear first row, inside right".

Information indicating the position of the axle to which each axle detector 15 is attached is stored in the storage unit 46 in association with the ID number of each axle detector 15 . In this embodiment, a total of six axle positions (front left, front right, rear first row left, rear first row right, rear second row left, rear second row right) are set in advance. , the ID number of each axle detector 15 is associated with one of the tire positions. For example, the ID number of the axle detector 15a is associated with the tire position "front left", and the ID number of the axle detector 16b is associated with the tire position "rear first row right".

When receiving the UHF signal from each tire detector 30, the monitoring unit 45 refers to the information stored in the storage unit 46 to determine the tire position of the ID number included in the UHF signal. The monitoring unit 45 updates the air pressure at the identified tire location 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 tire detector 32a, the monitoring unit 45 refers to the correspondence relationship between the ID number and the tire position stored in the storage section 46. FIG. As a result, the monitoring unit 45 identifies the tire position of the ID number included in the UHF signal as "right inner side of the first rear row". The monitoring unit 45 updates the specified air pressure of the "right inner side of the first rear row" with the tire air pressure included in the UHF signal.

The TPMS receiver 40 can cause the display unit 52 to display the information on the correspondence relationship between tire positions and tire pressures stored in the storage unit 46 . The display unit 52 is arranged at a position that can be visually recognized by the driver. The display unit 52 is arranged, for example, on an in-vehicle instrument panel.

The TPMS receiver 40 receives various information input by the user via the input unit 53 . Input unit 53 includes, for example, buttons and a touch screen. The input unit 53 is arranged, for example, on an in-vehicle instrument panel, similarly to the display unit 52 .

If the tire pressure included in the received UHF signal is equal to or lower than the low pressure threshold, the monitoring unit 45 causes the display unit 52 to display a warning and the tire position that is 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.

<Configuration of Tire Detector 30>
FIG. 2 is a block diagram showing the configuration of the tire detector 30. As shown in FIG. The tire detector 30 includes a controller 35, a pressure sensor 38, an acceleration sensor (G sensor) 39, an antenna A2, and a transmission 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 tire detector 30 shown in FIG. For example, the storage unit 36 included in the tire detector 13 of FIG. 1 stores "01" as the ID number, and the storage unit 36 included in the tire detector 14 stores "02" as the ID number. remembered.

In the double tire 21, the storage unit 36 included in the tire detector 31b stores "03" as the ID number, and the storage unit 36 included in the tire detector 31a stores "04" as the ID number. ing. In the double tire 22, the storage unit 36 included in the tire detector 32a stores "05" as the ID number, and the storage unit 36 included in the tire detector 32b stores "06" as the ID number. ing. In this manner, the ID number unique to each tire detector 30 is stored in the storage section 36 in each tire detector 30 .

The pressure sensor 38 detects tire air pressure and outputs the detection result (hereinafter also referred to as “tire air pressure P”) to the controller 35 . The acceleration sensor 39 detects uniaxial acceleration generated in the tire detector 30 and outputs the detection result (hereinafter also referred to as “acceleration G”) to the controller 35 . In addition to the pressure sensor 38 and the acceleration sensor 39, the tire detector 30 may further include a temperature sensor for detecting tire temperature.

Controller 35 controls transmitter circuit CT to transmit a UHF signal from antenna A2. The UHF signal to be transmitted includes the ID number stored in the storage unit 36, the information indicating the tire pressure P, the information indicating the acceleration G, the time information when the acceleration G was detected, and the like.

As described above, the tire detector 30 is activated and outputs a UHF signal when a predetermined activation condition is satisfied. The tire detector 30 is provided with a battery (not shown), and operates with electric power supplied from the battery. This battery is configured so that it cannot be easily charged from the outside. Therefore, in the tire detector 30 of Embodiment 1, it is desirable to reduce the power consumption of the tire detector 30 by shortening the operation time as much as possible.

From this point of view, the "predetermined activation condition" is set in advance so as to minimize the activation frequency of the tire detector 30 . For example, the predetermined start conditions include a timer start condition that a timer (not shown) measures that a predetermined timer time has elapsed since the previous stop, and acceleration G detected by the acceleration sensor 39 is a specific value (for example, maximum value or minimum value) may be included.

Note that the "timer time" used for the above-described timer activation condition may be a fixed value or a variable value that varies according to the acceleration G. FIG. For example, the controller 35 may determine whether the tire is rotating based on the acceleration G detected by the acceleration sensor 39, and change the set timer time.

More specifically, the controller 35 sets the timer time to a relatively long time (for example, about several minutes, or even longer, about several hours) when the tire is not rotating and is in a stopped state, and the tire is stopped. When the vehicle is running while rotating, the timer time may be set to a relatively short time (for example, several seconds, or even shorter, several milliseconds). In addition, the time for one activation of the tire detector 30 (the time from activation to next deactivation) may be limited to a relatively short time (for example, several milliseconds).

<Configuration of Axle Detector 15>
As an example, the axle detector 15 has a configuration obtained by removing the pressure sensor 38 from the configuration of the tire detector 30 shown in FIG. Regarding the configuration of axle detector 15, the description of the configuration that is the same as that of tire detector 30 will not be repeated.

The storage unit 36 in the axle detector 15 stores a unique ID number for each axle detector 15 shown in FIG. For example, the storage unit 36 included in the axle detector 15a of FIG. 1 stores "11" as the ID number, and the storage unit 36 included in the axle detector 15b stores "12" as the ID number. remembered. The storage unit 36 included in the axle detector 16a stores "13" as an ID number, and the storage unit 36 included in the axle detector 16b stores "14" as an ID number. there is Further, the storage unit 36 included in the axle detector 17a stores "15" as an ID number, and the storage unit 36 included in the axle detector 17b stores "16" as an ID number. there is

<Double tire configuration>
Vehicle 10 according to the present embodiment has double tires 21 to 24 on the rear wheels, which are non-steering wheels, as described above. FIG. 3 is an exploded perspective view of the double tire 22. FIG. An example of the configuration of the double tire 22 will be described with reference to FIG. 3 . The other double tires 21, 23, and 24 also have the same configuration as the double tire 22. As shown in FIG.

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. The wheels WH of the tires 22a, 22b have flat portions FP. The flat portion FP protrudes outward from the side portion (sidewall portion) of each tire. The tire 22a on the inner side of the vehicle and the tire 22b on the outer side of the vehicle are reversely connected. That is, the tires 22a and 22b are fixed with the flat portions FP of the wheels WH facing each other.

The tire 22a on the vehicle inner side is fixed to the axle R2 by passing the bolt BT of the hub H2 of the axle R2 through a hole provided in the flat portion FP of the wheel WH and tightening it with an inner nut NIN. A screw thread is formed on the tip side (outer side of the vehicle) of the inner nut NIN. An inner nut NIN as shown in FIG. 3 is attached to a wheel of a large vehicle such as a truck in accordance with the JIS system. On the other hand, the inner nut NIN is not attached in the ISO system. The wheel WH in the present embodiment may be a wheel conforming to either the JIS system or the ISO system.

The tire 22b on the outside of the vehicle is fixed to the tire 22a on the inside of the vehicle by threading the thread on the tip side of the inner nut NIN into a hole provided in the flat portion FP of the wheel WH and fastening it with a wheel nut NW. As a result, the tire 22a and the tire 22b are connected to each other and connected to the same axle R2.

The tire 22a is fixed so that the rotation axis of the axle R2 and the rotation axis of the tire 22a are coaxial. Similarly, the tire 22b is fixed so that the rotation axis of the axle R2 and the rotation axis of the tire 22b are coaxial. The tire Tr including the double tire 22 is fixed so that the rotation axis of the axle Ax to which the tire Tr is attached and the rotation axis of the tire Tr are coaxial.

<External view of tire detector 30>
FIG. 4 is an external perspective view of the tire detector 30 attached to the wheel WH. The tire detector 30 is fixedly supported by the wheel WH. FIG. 4 shows a rotation axis direction D1, a rotation circumferential direction D2, and a rotation radial direction D3 of the wheel WH when the tire Tr rotates. The acceleration sensor 39 of the tire detector 30 in the present embodiment is a uniaxial acceleration sensor whose detection direction is the rotational radial direction D3. The detection direction of the acceleration sensor 39 of the tire detector 30 is not limited to the rotation radial direction D3, and may be any direction orthogonal to the rotation axis direction D1. That is, the detection direction of the acceleration sensor 39 of the tire detector 30 may be the rotational circumferential direction D2.

<Detected value of acceleration sensor 39 in tire detector 32a>
FIG. 5 is a transition diagram of the arrangement of the tire detector 32a when the tire 22a on the inside of the vehicle rotates. FIG. 5 shows the transition of the arrangement of the tire detector 32a when the tire 22a is viewed from the positive side of the Y-axis direction (outside of the vehicle 10). In other words, FIG. 5 shows the transition of the arrangement of the tire detector 32a when the tire 22a is viewed from the flat portion FP side of the wheel WH of the tire 22a.

FIG. 5 shows layouts 1h to 12h as examples of 12 pattern layouts of the tire detectors 32a. The arrangement 12h of the tire detectors 32a is an arrangement in which the tire detectors 32a are positioned in the rotational radial direction D3 extending in the positive direction of the Z-axis from the center point CP1 of the tire 22a. The arrangement 12h is hereinafter referred to as the "0 degree" or "+360 degree" arrangement.

Arrangement 1h is the arrangement of the tire detector 32a when the tire 22a is rotated clockwise by θ degrees from the state of arrangement 12h. θ degree in FIG. 7 is 30 degrees. The arrangement 1h is hereinafter referred to as the "+30 degrees" arrangement. Furthermore, the arrangement 2h is the arrangement of the tire detector 32a when the tire 22a is rotated clockwise by θ degrees from the state of the arrangement 1h. The arrangement 2h is hereinafter referred to as the "+60 degrees" arrangement.

The arrangement 3h is the arrangement of the tire detector 32a when the tire 22a is rotated clockwise by θ degrees from the state of the arrangement 2h. The arrangement 3h is hereinafter referred to as the "+60 degrees" arrangement. Thus, in FIG. 5, 12 degrees of 0 degrees (360 degrees), 30 degrees, +60 degrees, +90 degrees, +120 degrees, +150 degrees, +180 degrees, +210 degrees, +240 degrees, +270 degrees, +300 degrees, +330 degrees An example arrangement of tire detectors 30 in a pattern is shown. FIG. 5 shows detected values of the acceleration sensor 39 when the vehicle 10 is stopped.

As described with reference to FIG. 4, the acceleration sensor 39 of the tire detector 30 is a uniaxial acceleration sensor that detects acceleration in only one direction, and the detection direction is the tire radial direction (rotational radial direction). Therefore, as shown in FIG. 5, the gravitational acceleration in the detection direction is greatest when the tire detector 30 is at the position 12h (0 degrees) or at the position 6h (+180 degrees).

In the example of FIG. 5, the detection value of the acceleration sensor 39 when the tire detector 30 is at the position 12h is +1G. Also, the detection value of the acceleration sensor 39 when the tire detector 30 is at the position 6h is -1G.

When the tire detector 30 is in the arrangement 1h or 11h, the detection value of the acceleration sensor 39 is +√3/2G. When the tire detector 30 is in the position 2h or position 10h, the detection value of the acceleration sensor 39 is +1/2G. The detection value of the acceleration sensor 39 is 0G when the tire detector 30 is at the position 3h or position 9h.

When the tire detector 30 is at the position 5h or the position 7h, the detection value of the acceleration sensor 39 is -√3/2G. When the tire detector 30 is in the 4h or 8h position, the detected value of the acceleration sensor 39 is -1/2G. Depending on the mounting direction of the tire detector 30, the sign of the gravitational acceleration of the detected value shown in FIG. 5 may be reversed.

Tire detector 30 transmits a UHF signal including the detection value of acceleration sensor 39 to monitoring unit 45 . The monitoring unit 45 can estimate the arrangement of the tire detectors 30 from the detection values of the acceleration sensor 39 . As shown in FIG. 5, each detection value of the acceleration sensor 39 is symmetrical with respect to the Z-axis passing through the center point CP1.

The monitoring unit 45 can acquire at least two placement candidates for the tire detectors 30 based on the detection values of the acceleration sensor 39 . For example, when the detection value of the acceleration sensor 39 is +√3/2G, the monitoring unit 45 acquires the placement 1h and the placement 11h as the placement candidates. When the detection value of the acceleration sensor 39 is -1/2G, the monitoring unit 45 acquires the placement 4h and the placement 8h as the placement candidates.

Also, when the detection value of the acceleration sensor 39 is +1 G, the monitoring unit 45 estimates that the tire detector 30 is at the position 12h. Also, the monitoring unit 45 estimates that the tire detector 30 is at the position 6h when the detection value of the acceleration sensor 39 is -1G.

The tire detector 30 is fixedly attached to the wheel WH of the tire Tr. That is, the arrangement of the tire detectors 30 indicates at which rotation angle the tire Tr is stopped.

<External View of Axle Detector 15>
FIG. 6 is an external perspective view of the axle detector 15 attached to the axle Ax. The axle detector 15 is fixedly supported by the axle Ax. FIG. 6 shows a rotation axis direction D1, a rotation circumferential direction D2, and a rotation radial direction D3 when the axle Ax rotates. As shown in FIG. 3, the axis of rotation of the axle Ax is coaxial with the axis of rotation of the wheel WH.

The acceleration sensor 39 of the axle detector 15 is, like the acceleration sensor 39 of the tire detector 30, a uniaxial acceleration sensor whose detection direction is the rotational radial direction D3. Also, the detection direction of the acceleration sensor 39 of the axle detector 15 is not limited to the rotation radial direction D3, and may be any direction perpendicular to the rotation axis direction D1. Axle Ax has an end face FP<b>2 that is exposed when axle Ax is attached to vehicle 10 .

<Detected Value of Acceleration Sensor 39 in Axle Detector 16b>
FIG. 7 is a layout transition diagram of the axle detector 16b when the axle R2 rotates. FIG. 7 shows a cross section when the axle R2 is viewed from the positive direction side of the Y-axis (outside of the vehicle 10) and the transition of the arrangement of the axle detector 16b.

As in FIG. 5, FIG. 7 shows layouts 1h to 12h as layout examples of 12 patterns of axle detectors 16b. Since the arrangement of axle detector 16b and the detection value of acceleration sensor 39 are the same as in FIG. 5, the description will not be repeated.

That is, the monitoring unit 45 can estimate the placement of the axle detector 15 based on the detection value of the acceleration sensor 39 of the axle detector 15 in addition to the placement of the tire detector 30 . FIG. 8 is a diagram showing the relationship between the arrangement of the acceleration sensor 39 shown in FIGS. 5 and 7 and the detected values. 5 to 7, examples of arrangement of the tire detector 30 and the axle detector 15 with respect to 12 patterns of rotation angles of the tire Tr or the axle Ax have been described. Even when the tire Tr or the axle Ax stops at other rotation angles, the detection value of the acceleration sensor 39 changes according to the phase shown in FIG.

<Determination of tire position>
A specific method of determining tire positions in the vehicle 10 will be described below with reference to FIGS. 9 to 18. FIG. The tire position determination system in the present embodiment uses the relationship between the rotation angle of the tire Tr and the rotation angle of the axle Ax to determine which tire Tr is attached to which axle Ax. That is, the tire position determination system determines the combination of axle Ax and tire Tr. As a result, the tire position determination system automatically determines tire positions even after tire rotation.

The relationship between the rotation angle of the tire Tr and the rotation angle of the axle Ax is acquired by the monitoring unit 45 based on the detection values of the acceleration sensors 39 of the tire detector 30 and the axle detector 15 . 9 and 10 are used to describe the relationship between the tire Tr rotation angle and the axle Ax rotation angle. I will explain an example.

To simplify the explanation, the autolocation function will be described only for the double tires 21 and 22. However, the tire position determination system applies to all the tires Tr and axles Ax provided in the vehicle 10. It has an autolocation function that determines the tire position as

FIG. 9 is a diagram showing the arrangement of the double tire 22 on the right side of the first rear row and the axle R2 when viewed from the positive direction side of the Y axis. FIG. 9 shows wheels WH of tires 22a and 22b, tire detectors 32a and 32b, axle R2, and axle detector 16b when vehicle 10 is stopped.

FIG. 9 shows the arrangement relationship between the tire detectors 32a, 32b and the axle detector 16b in this embodiment. When axle detector 16b is at location 12h, tire detector 32a is at location 1h and tire detector 32b is at location 9h. The arrangement relationship between the tire detectors 32a, 32b and the axle detector 16b shown in FIG. 9 is merely an example, and the tire detectors 32a, 32b and the axle detector 16b may be arranged in other arrangement relationships. good too.

Tire detectors 32a and 32b are fixed to wheels WH of tires 22a and 22b, respectively. That is, the arrangement of the tire detectors 30 indicates at which rotation angle the tire Tr is stopped. Axle detector 16b is fixed to axle R2. That is, the arrangement of the axle detector 15 indicates at which rotation angle the axle Ax is stopped. By acquiring the arrangement relationship between the tire detectors 32a, 32b and the axle detector 16b, the monitoring unit 45 can acquire the correspondence relationship between the rotation angles of the tires 22a, 22b and the axle R2.

FIG. 10 is a diagram showing the arrangement of the double tire 21 on the left side of the first rear row and the axle R1 when viewed from the negative direction side of the Y axis. FIG. 10 shows wheels WH of tires 21a and 21b, tire detectors 31a and 31b, axle R1, and axle detector 16a when vehicle 10 is stopped.

The tire detectors 31a and 31b and the axle detector 16a are arranged in a layout relationship as shown in FIG. When axle detector 16a is at location 12h, tire detector 31a is at location 10h and tire detector 31b is at location 12h. The arrangement relationship between the tire detectors 31a, 31b and the axle detector 16a shown in FIG. 10 is merely an example, and the tire detectors 31a, 31b and the axle detector 16a may be arranged in another arrangement relationship. .

By acquiring the arrangement relationship between the tire detectors 31a and 31b and the axle detector 16a, the monitoring unit 45 can acquire the correspondence relationship between the rotation angles of the tires 21a and 21b and the rotation angle of the axle R1.

<Acquisition of rotation angle>
The monitoring unit 45 acquires the arrangement of the tire detectors 30 based on the detection value of the acceleration sensor 39 of the tire detector 30, and determines the position of the axle detector 15 based on the detection value of the acceleration sensor 39 of the axle detector 15. place. The monitoring unit 45 uses the acquired relationship between the arrangement of the tire detectors 30 and the arrangement of the axle detectors 15 to acquire the correspondence relationship between the rotation angle of the tire Tr and the rotation angle of the axle Ax.

Each of the tire detector 30 and the axle detector 15 is intermittently activated at mutually different timings and transmits UHF signals. Since the tire Tr rotates while the vehicle 10 is running, the detection value of the acceleration sensor 39 changes with time. Therefore, the monitoring unit 45 cannot acquire the positional relationship between the tire detector 30 and the axle detector 15 while the vehicle 10 is running, even using the received UHF signal.

The monitoring unit 45 detects the tire detectors 30 and the acceleration sensor 39 of the axle detector 15 while the vehicle 10 is stopped in order to obtain the positional relationship between the tire detectors 30 and the axle detectors 15 . Use the detected value. 11 and 12, the positional relationship between the tire detector 30 and the axle detector 15 at an arbitrary stop timing of the vehicle 10 will be described below.

The monitoring unit 45 determines whether the vehicle 10 is stopped based on the traveling speed received from a device (not shown) for detecting the traveling speed of the vehicle 10 .

FIG. 11 is a diagram showing the arrangement of the double tire 22 on the right side of the first rear row and the axle R2 when viewed from the positive direction of the Y axis during the first stop period. The first stop period is any period during which the vehicle 10 stops. The start time of the first stop period is when the vehicle 10 stops, and the end time of the first stop period is when the vehicle 10 starts. Since the tire Tr and the axle Ax rotate as the vehicle 10 travels, the rotation angle of the tire Tr and the axle Ax when the vehicle 10 is stopped differs each time the vehicle 10 stops. In the first stop period, the double tire 22 and the axle R2 are stopped while rotating clockwise by 30 degrees from the state shown in FIG.

FIG. 12 is a diagram showing the arrangement of the double tire 21 on the left side of the first rear row and the axle R1 when viewed from the negative direction side of the Y axis during the first stop period. In the first stopping period, the double tire 21 and the axle R1 are stopped after being rotated 120 degrees clockwise from the state shown in FIG.

During the first stop period, the tire detectors 31a, 31b, 32a, 32b and the axle detectors 16a, 16b intermittently transmit UHF signals at different timings. The monitoring unit 45 causes the storage unit 46 to store information indicated by the UHF signals received at different timings. FIG. 13 is a table of the storage unit 46 that collectively stores the UHF signals received from the tire detector 30 and the axle detector 15 during the first stop period.

The No column indicates an identifier for identifying data for each UHF signal. The ID column indicates a unique ID that each of tire detector 30 and axle detector 15 has. Detected values of the acceleration sensor 39 are shown in the gravity (G) column. A stop ID column indicates the stop period when the UHF signal is received. The estimated angle column indicates the rotation angle of the tire Tr or axle Ax estimated by the monitoring unit 45 .

Upon receiving the UHF signal, the monitoring unit 45 obtains information indicating the ID string and gravity (G) contained in the UHF signal, and stores them in the table of FIG. 13 . The monitoring unit 45 generates a new No column identifier based on the newly received UHF signal, and stores it together with the data obtained from the UHF signal. Also, the monitoring unit 45 generates a new stop ID every time the vehicle 10 stops, and stores the corresponding stop ID based on the time when the UHF signal is received.

The monitoring unit 45 estimates the placement of the axle detector 15 or tire detector 30 based on the information shown in the Gravity (G) column. For example, for the No column "101", the ID column value is "13". ID "13" is previously associated with the axle detector 16a by another table stored in the storage unit 46. FIG. The monitoring unit 45 can determine that the data shown in column No "101" is data based on the UHF signal transmitted by the axle detector 16a.

For the No column "101", the value in the Gravity (G) column is "-1/2". As explained with reference to FIG. 7, the arrangement of the axle detector 16a at which the gravitational acceleration can be -1/2 is the arrangement 4h (+120 degrees) or the arrangement 8h (+240 degrees). The monitoring unit 45 can estimate that the arrangement of the axle detector 16a when receiving the UHF signal of No column "101" is the arrangement 4h (+120 degrees) or the arrangement 8h (+240 degrees).

The monitoring unit 45 estimates the arrangement of the axle detector 16a from the gravitational acceleration value, converts the estimated arrangement into angle information, and stores the information in an estimated angle sequence. The estimated angle column stores data indicating that the arrangement of the axle detector 16a is 120 degrees or 240 degrees. The estimated angle column represents the rotation angle of the axle Ax.

Thus, the monitoring unit 45 uses the UHF signals received from each of the axle detectors 15 to estimate the rotation angle of the axle Ax during the first stop period. Also, the monitoring unit 45 estimates the rotation angle of the tire Tr using the UHF signal received from each of the tire detectors 30 during the first stop period. FIG. 13 shows a table in which the estimated angles of the tire detectors 31a, 31b, 32a, 32b and the axle detectors 16a, 16b are stored.

<Acquisition of Correspondence Relationship of Rotation Angles in First Stop Period>
FIG. 14 is a table showing the correspondence of rotation angles in the first stop period. FIG. 14 shows the correspondence relationship between the rotation angle of each axle detector 15 and the rotation angle of each tire detector 30 during the first stop period. Note that the first suspension period may correspond to the "first period" in the present disclosure.

For example, in the table of FIG. 14, the rotation angle of the axle R1 to which the axle detector 16a with the ID number "13" is attached and the tire 21b to which the tire detector 31b with the ID number "03" is attached. Information "0 degrees or 120 degrees" is stored as a correspondence relationship with the rotation angle of .

The monitoring unit 45 acquires the correspondence relationship between the rotation angle of the axle R1 and the rotation angle of the tire 21b based on the estimated angle estimated in FIG. Specifically, the monitoring unit 45 obtains the angle difference for each combination of estimated angles.

As shown in FIG. 13, the placement of axle detector 16a with ID number "13" is presumed to be placement 4h (+120 degrees) or placement 8h (+240 degrees). Similarly, the arrangement of the tire detector 31b with the ID number "03" is estimated to be the arrangement 4h (+120 degrees) or the arrangement 8h (+240 degrees).

When the axle detector 16a is at the position 4h (+120 degrees) and the tire detector 31b is at the position 4h (+120 degrees), the angular difference is 0 degrees. Further, when the axle detector 16a is at the position 4h (+120 degrees) and the tire detector 31b is at the position 8h (+240 degrees), the angle difference is 120 degrees.

If the axle detector 16a is at the position 8h (+240 degrees) and the tire detector 31b is at the position 4h (+120 degrees), the angular difference is 120 degrees. Also, when the axle detector 16a is at the position 8h (+240 degrees) and the tire detector 31b is at the position 8h (+240 degrees), the angle difference is 0 degrees. That is, the angle difference in each combination of the estimated angles of ID number "13" and ID number "03" is 0 degrees or 120 degrees.

The table in FIG. 14 also shows the rotation angle of the axle R1 to which the axle detector 16a with the ID number "13" is attached, and the tire 21b to which the tire detector 31b with the ID number "05" is attached. Information of "60 degrees or 180 degrees" is stored as a correspondence relationship with the rotation angle of .

As shown in FIG. 13, the placement of axle detector 16a with ID number "13" is presumed to be placement 4h (+120 degrees) or placement 8h (+240 degrees). Also, the arrangement of the tire detector 32a with the ID number "05" is presumed to be the arrangement 2h (+60 degrees) or the arrangement 10h (+300 degrees).

If the axle detector 16a is at position 4h (+120 degrees) and the tire detector 32a is at position 2h (+60 degrees), the angular difference is 60 degrees. Further, when the axle detector 16a is at the position 4h (+120 degrees) and the tire detector 32a is at the position 10h (+300 degrees), the angle difference is 180 degrees.

If the axle detector 16a is at position 8h (+240 degrees) and the tire detector 32a is at position 2h (+60 degrees), the angular difference is 180 degrees. Further, when the axle detector 16a is at the position 8h (+240 degrees) and the tire detector 32a is at the position 10h (+300 degrees), the angle difference is 60 degrees. That is, the angle difference in each combination of the estimated angles of ID number "13" and ID number "05" is 60 degrees or 180 degrees.

In this way, the monitoring unit 45 acquires the angle difference between the estimated angles in each ID number combination and stores it in the table of FIG. Thereby, the monitoring unit 45 obtains the correspondence relationship between the rotation angle of each axle Ax and the rotation angle of each tire Tr during the first stop period. Each piece of data shown in FIG. 14 may correspond to the "first correspondence" in the present disclosure.

<Acquisition of Correspondence Relationship of Rotation Angles in Second Stop Period>
After obtaining the correspondence relationship in the first stop period shown in FIG. 14, the monitoring unit 45 again monitors the rotation angle of each axle Ax and the rotation of each tire Tr in the second stop period after the first stop period. Get the correspondence with the angle. Note that the second suspension period may correspond to the "second period" in the present disclosure.

FIG. 15 is a diagram showing the arrangement of the double tire 22 on the right side of the first rear row and the axle R2 when viewed from the positive direction of the Y axis during the second stop period. The second stop period is a period that starts when the vehicle 10 stops again after the first stop period ends when the vehicle 10 starts moving. The second stop period ends when the vehicle 10 starts again. In the second stopping period, the double tire 22 and the axle R2 are stopped after being rotated 150 degrees clockwise from the state shown in FIG.

FIG. 16 is a diagram showing the arrangement of the double tire 21 on the left side of the first rear row and the axle R1 when viewed from the negative direction side of the Y axis during the second stop period. In the second stop period, the double tire 21 and the axle R1 are stopped after being rotated 270 degrees clockwise from the state shown in FIG.

FIG. 17 is a table of the storage unit 46 that collectively stores the UHF signals received from each of the tire detector 30 and the axle detector 15 during the second stop period. The data shown in the table of FIG. 17 are stored by the monitoring unit 45 in a manner similar to that described in FIG.

FIG. 18 is a table showing the correspondence of rotation angles in the second stop period. The monitoring unit 45 acquires the correspondence relationship of the rotation angles in the second stop period based on the table shown in FIG. 17 . The data shown in the table of FIG. 18 are stored by the monitoring unit 45 in a manner similar to that described in FIG. Each data shown in FIG. 18 may correspond to the “second correspondence” in the present disclosure.
<Comparison of correspondence>
The monitoring unit 45 compares the correspondence of the first stop period shown in FIG. 14 with the correspondence of the second stop period shown in FIG. It is determined whether the tire Tr is attached. That is, the monitoring unit 45 determines the combination of the axle Ax and the tire Tr.

The monitoring unit 45 refers to the table of FIG. 14 and the table of FIG. 18 stored by the storage unit 46 . The monitoring unit 45 compares the angle difference at the first stop and the angle difference at the second stop for ID number "13" and ID number "03".

The angle difference at the first stop is "0 degrees or 120 degrees". The angle difference at the second stop is "0 degrees or 180 degrees". The angle difference at the first stop and the angle difference at the second stop commonly include "0 degree". When both the angle difference at the first stop and the angle difference at the second stop are "0 degree", it means that the relationship indicated by the ID number "13" and the ID number "03" has not changed. means. More specifically, the rotation angle of the axle R1 to which the axle detector 16a with the ID number "13" is attached and the rotation angle of the tire 21b to which the tire detector 31b with the ID number "03" is attached. does not change between the time of the first stop and the time of the second stop.

As described above, the tire Tr attached to the axle Ax rotates in synchronization with the rotation of the attached axle Ax. Therefore, the angular difference between the rotation angle of the axle Ax and the rotation angle of the tire Tr attached to the axle Ax is the same between the first stop and the second stop.

When both the angle difference at the first stop and the angle difference at the second stop are "0 degree", the monitoring unit 45 monitors the rotation angle of the axle R1 and the tire It can be determined that the angle difference with the rotation angle of 21b is the same. Accordingly, the monitoring unit 45 determines that the tire 21b may be attached to the axle R1.

Next, an example of comparing the angle difference at the first stop and the angle difference at the second stop for ID number "13" and ID number "05" will be described.

The angle difference at the first stop is "60 degrees or 180 degrees". The angle difference at the second stop is "90 degrees". The angle difference at the first stop and the angle difference at the second stop do not include a common angle difference. That is, it means that the relationship indicated by the ID number "13" and the ID number "05" changed between the time of the first stop and the time of the second stop.

More specifically, the rotation angle of the axle R1 to which the axle detector 16a with the ID number "13" is attached and the rotation angle of the tire 22a to which the tire detector 32a with the ID number "05" is attached. The correspondence has changed between the time of the first stop and the time of the second stop. Since the angular difference of the axle Ax and the angular difference of the tires Tr attached to the axle Ax do not change between the first stop and the second stop, the monitoring unit 45 detects that the axle R1 , it can be determined that the tire 22a is not mounted.

In this way, the monitoring unit 45 detects that the tire Tr associated with the ID number is aligned with the axle Ax if the angle difference at the time of the first stop and the angle difference at the time of the second stop include a common angle difference. Determine that it may be installed. If the angle difference at the first stop and the angle difference at the second stop do not include a common angle difference, the monitoring unit 45 determines that the tire Tr associated with the ID number is attached to the axle Ax. It can be determined that the

In the examples of FIGS. 14 and 18, the common angle difference. The monitoring unit 45 can determine that the tires 21b and 21b may be attached to the axle R1, and the tires 22a and 22b may be attached to the axle R2.

On the other hand, each combination of ID numbers "13" and "03", ID numbers "13" and "04", ID numbers "14" and "05", and ID numbers "14" and "06" includes a common angular difference. not The monitoring unit 45 can determine that the tires 22a and 22b are not attached to the axle R1 and the tires 21b and 21b are not attached to the axle R2.

In this way, the monitoring unit 45 uses the result of comparing the angle difference in the rotation angle at the first stop and the angle difference in the rotation angle at the second stop to determine which tire Tr is synchronized with which axle Ax. and determine whether or not to rotate. That is, the monitoring unit 45 determines which tire Tr is not attached to which axle Ax.

Note that even when the tire Tr is not attached to the axle Ax, a common angle difference may be included depending on the rotation angle at the first stop and the rotation angle at the second stop. By performing comparison processing in a plurality of stop periods, it is possible to determine a combination indicating which tire Tr is attached to which axle Ax.
<Procedure for Tire Position Determination>
FIG. 19 is a flow chart showing tire position determination processing by the monitoring unit 45 . The monitoring unit 45 determines whether the vehicle 10 has stopped (step S101). That is, the monitoring unit 45 determines whether the tire Tr and the axle Ax are stopped.

If the vehicle 10 is not stopped (NO in step S101), the monitoring unit 45 leaves the process at step S101. If the vehicle 10 is stopped (YES in step S101), the monitoring unit 45 determines whether or not a UHF signal has been received from the tire detector 30 or the axle detector 15 (step S102). Tire detector 30 and axle detector 15 intermittently transmit UHF signals at different timings.

When the UHF signal is received (YES in step S102), the monitoring unit 45 stores the information included in the UHF signal together with the stop ID in the storage section 46 (step S103).

If the UHF signal has not been received (NO in step S102), it is determined whether or not the vehicle 10 has started (step S104). If the vehicle 10 has not started (NO in step S104), the monitoring unit 45 returns the process to step S102. If the vehicle 10 has started (YES in step S104), the monitoring unit 45 updates the stop ID (step S105). That is, the monitoring unit 45 generates a stop ID to be given when the vehicle stops next time.

The monitoring unit 45 determines whether there are a plurality of stop IDs for which the information of the UHF signal from each of the tire detector 30 and the axle detector 15 is complete (step S106). That is, the tire detectors 30 and the axle detectors 15 intermittently transmit UHF signals at different timings. is not limited. Therefore, the monitoring unit 45 determines whether there are at least two stopping periods in which UHF signals have been received from all tire detectors 30 and axle detectors 15 .

If there is not a plurality of stop IDs for which the UHF signal information from each of the tire detector 30 and the axle detector 15 is complete (NO in step S106), the monitoring unit 45 repeats the processing from step S101 to step S106. . When there are a plurality of stop IDs for which the information of the UHF signal from each of the tire detector 30 and the axle detector 15 is complete (YES in step S106), the monitoring unit 45 detects different stop IDs. , the angle difference of the rotation angle is compared.

The monitoring unit 45 determines which tire Tr is not attached to which axle Ax. At this time, the monitoring unit 45 determines which tire Tr may be attached to which axle Ax. The monitoring unit 45 can improve the accuracy of the determination result by repeating the processing procedure shown in FIG. 19 a plurality of times.

As described above, in the monitoring unit 45 of the present embodiment, the rotation angle of the tire Tr is estimated based on the detection value of the tire detector 30, and the rotation angle of the axle Ax is estimated based on the detection value of the axle detector 15. Presumed. In the first stop period, the estimated "rotational angle of the tire Tr" may correspond to the "first value" in the present disclosure. In the first stop period, the estimated "rotational angle of the axle Ax" may correspond to the "second value" in the present disclosure.

Also, in the second stop period, the estimated "rotational angle of the tire Tr" may correspond to the "third value" in the present disclosure. In the second stop period, the estimated "rotational angle of the axle Ax" may correspond to the "fourth value" in the present disclosure. The monitoring unit 45 does not estimate the rotation angle of the tire Tr and the rotation angle of the axle Ax based on the detection value of the tire detector 30 and the detection value of the axle detector 15. And the tire position may be determined only from the detected value of the axle detector 15 . That is, the monitoring unit 45 uses only the detection value of the acceleration sensor 39 without converting the detection value of the acceleration sensor 39 into the "estimated angle" shown in FIGS. A comparison process may be performed between them to determine the tire position.

[Modification 1 of Embodiment 1]
In the tire position determination system described above, as shown in FIGS. 9 and 10, the axle detector 15 and the tire detector 30 are installed at arbitrary positions by the user. The arrangement of 30 has no regularity. However, the axle detector 15 and tire detector 30 may be pre-mounted in a specific arrangement.

For example, the tire detectors 31a and 31b attached to the tires 21a and 21b, respectively, and the axle detector 16a attached to the axle R1 can be attached so that the mutual angle difference is 0 degree in advance. Similarly, the tire detectors 32a and 32b attached to the tires 22a and 22b, respectively, and the axle detector 16b attached to the axle R2 can be attached so that the mutual angle difference is 0 degree in advance.

Thus, when the arrangement of the axle detector 15 and the tire detector 30 is determined in advance, the monitoring unit 45 receives information on the arrangement of the axle detector 15 and the tire detector 30 via the input section 53. to get For example, input unit 53 receives information regarding the arrangement of axle detector 15 and tire detector 30 . As a result, the monitoring unit 45 can perform comparison processing using the correspondence acquired from the information on the arrangement of the axle detector 15 and the tire detector 30 and the correspondence of the rotation angle estimated during the stop period.

FIG. 20 is a table of the storage unit 46 that stores UHF signals received during the first stop period when the axle detector 15 and the tire detector 30 are attached in advance in a specific arrangement. FIG. 21 is a table of the storage unit 46 that stores UHF signals received during the second stop period when the axle detector 15 and the tire detector 30 are attached in advance in a specific arrangement.

As described above, when the tire detector 30 and the axle detector 15 are mounted so that the angle difference between them is 0 degrees, as shown in FIG. The arrangement of the tire detector 30 and the axle detector 15 estimated by 12h can be the arrangement 12h (0 degree). As shown in FIG. 21, since the axle R1 and the axle R2 do not rotate synchronously, the arrangement of the tire detector 30 and the estimated tire detector 30 and axle detector 15 are different in the second stop period. becomes.

That is, the detected values of the acceleration sensors of the axle detector 16a corresponding to the ID number "13", the tire detector 31b corresponding to the ID number "03", and the tire detector 31a corresponding to the ID number "04" are +1. Become. Further, the detection values of the acceleration sensors of the axle detector 16b corresponding to the ID number "14", the tire detector 32a corresponding to the ID number "05", and the tire detector 32b corresponding to the ID number "06" are +1/ 2.

In this way, even when the axle detector 15 and the tire detector 30 are attached in advance in a specific arrangement, the monitoring unit 45 detects the rotation angle of the axle Ax and the tire Tr attached to the axle Ax. does not change, it is possible to determine the combination of the axle Ax and the tire Tr attached to the axle Ax.

[Modification 2 of Embodiment 1]
In the embodiment described above, the axle detector 15 was attached to the side of the axle Ax, as shown in FIG. However, the axle detector 15 may be mounted on the end face FP2 of the axle Ax.

FIG. 22 is an external perspective view of the axle detector 15 attached to the axle Ax in Modification 2. As shown in FIG. An end face FP2 of an axle Ax employed in a large vehicle such as a truck or bus is attached so as to pass through a wheel WH of a tire Tr, as shown in FIG. That is, end face FP2 is exposed to the outside of vehicle 10 when axle Ax is attached to vehicle 10 .

If the tire Tr is coupled to the vehicle body using an axle shaft, it may be difficult to place the axle detector 15 on the side of the axle Ax that synchronizes rotation with the tire Tr. Therefore, as shown in FIG. 22, the axle detector 15 is attached to the end face FP2 exposed when the axle Ax is attached to the vehicle 10, thereby facilitating attachment of the axle detector 15. can be done.

[Modification 3 of Embodiment 1]
An example of the monitoring unit 45 of the above-described embodiment performing tire position determination using the detection values of the axle detector 15 and the tire detector 30 while the vehicle is stopped has been described. However, the monitoring unit 45 may use the detection values of the axle detector 15 and the tire detector 30 during travel to determine the tire position by time synchronization.

In the tire position determination system according to Modification 3, each tire detector 30 and each axle detector 15 is provided with a timer for time synchronization. Each tire detector 30 and each axle detector 15 all have time synchronized timers. Each tire detector 30 and each axle detector 15 transmits a UHF signal when the timer reaches a specific time. Thereby, the monitoring unit 45 can acquire the detection value of each tire detector 30 and the detection value of each axle detector 15 at the same timing.

Alternatively, the tire position determination system may have an initiator that sends command signals to each tire detector 30 and each axle detector 15 . The initiator collectively transmits a command signal to each tire detector 30 . Each tire detector 30 transmits a UHF signal to the monitoring unit 45 with the reception of the command signal as a predetermined activation condition. Thereby, the monitoring unit 45 can acquire the detection value of each tire detector 30 and the detection value of each axle detector 15 at the same timing.

[Embodiment 2]
In the first embodiment described above, by obtaining a combination of the axle detector 15 attached to the axle Ax and the tire detector 30 attached to the tire Tr, the tire Tr to which the tire detector 30 is attached is detected. A tire position determination system for determining position has been described. In the tire position determination system according to Embodiment 2, an example in which a nut looseness detector is used instead of the axle detector 15 will be described. In the second embodiment, the description of the configuration overlapping with that of the first embodiment will not be repeated.

In the example of Embodiment 2, one nut looseness detector is provided for one axle Ax. That is, since vehicle 10 in Embodiment 2 has six axles Ax, vehicle 10 is similarly provided with six nut looseness detectors. Hereinafter, all the nut looseness detectors provided in vehicle 10 according to the second embodiment are collectively referred to as "nut looseness detectors 70".

The nut looseness detector 70 has a structure obtained by removing the pressure sensor 38 from the structure of the tire detector 30 shown in FIG. That is, nut looseness detector 70 has the same configuration as axle detector 15 described in the first embodiment.

FIG. 23 shows the nut looseness detector 71 attached to the nut NW. The nut looseness detector 71 is a nut looseness detector corresponding to the axle R2. FIG. 23 shows one of the nuts NW used for the vehicle inner tire 22a and the vehicle outer tire 22b shown in FIG. In FIG. 23, the illustration of the inner nut NIN described in FIG. 3 is omitted for simplification of illustration.

As shown in FIG. 23, nuts NW and bolts BT fasten wheels WH of tires 22b and 22a to hubs H2. Specifically, the nut NW is screwed onto the bolt BT inserted into the wheel hole 221, thereby fastening the wheel WH of the tires 22b, 22a to the hub H2.

A nut cap 241 is attached to the vehicle outer side of the nut NW. As shown in FIG. 23, the nut cap 241 includes a ceiling portion 241a and side portions 241b. The side portion 241b is provided so as to circumferentially surround the nut NW. The ceiling portion 241a is provided so as to face the tip portion 251 of the bolt BT. A washer 243 is provided between the nut NW and the wheel WH.

In the example of Embodiment 2, the nut looseness detector 71 is attached to the inner surface 241c of the ceiling portion 241a of the nut cap 241 . That is, the nut looseness detector 71 is arranged in the space S of the nut cap 241 that accommodates the bolt BT. Note that the nut looseness detector 71 may be attached to the nut NW itself instead of the nut cap 241 .

The nut looseness detector 71 acquires the relative positional relationship between the nut NW and the vehicle body, for example, based on the uniaxial acceleration detected by the acceleration sensor, and determines whether the nut NW is loose. Any method for detecting nut looseness may be used as long as the nut looseness detector 70 includes an acceleration sensor. For example, the nut looseness detector 70 uses a magnetic sensor to detect looseness of the nut NW. You may In Embodiment 2, the nut NW is an example of the "first rotor" of the present disclosure. Also, the nut looseness detector 70 is an example of the "rotating body detector" in the present disclosure.

The tire position determination system of the second embodiment acquires a combination of nut looseness detector 70 and tire detector 30 using the method described in the first embodiment. That is, each of nut looseness detector 70 and tire detector 30 has an acceleration sensor, and transmits the detection value of the acceleration sensor to monitoring unit 45 . When the nut NW is not loosened, the nut NW rotates in synchronization with the tire Tr.

In the present disclosure, "rotating body that rotates in synchronism with the tire Tr" refers to an object that rotates at the same angular velocity (rad/s) about the rotation axis of the tire Tr. Note that "rotating in synchronism with the tire Tr" means that a member attached to the tire Tr rotates together with the tire Tr. As a result, it rotates or revolves around the same rotation axis as that of the tire Tr. The axle Ax is fixed at a position overlapping the rotation axis Ar1 of the tire Tr shown in FIG. Therefore, when the tire Tr rotates, the axle Ax rotates integrally with the tire Tr around the rotation axis Ar1 of the tire Tr.

On the other hand, the nut NW is fixed to the wheel WH at a position away from the rotation axis Ar1 of the tire Tr. orbit around. Therefore, the axle Ax and the nut NW rotate synchronously with the tire Tr.

Therefore, in the second embodiment as well, the monitoring unit 45 can obtain a corresponding combination from the detected value of the acceleration sensor and the detected value of the tire detector 30 received from the nut looseness detector 70 .

Furthermore, in Embodiment 2, each of the nut looseness detectors 70 transmits information including a unique identifier to the monitoring unit 45 in addition to the detection value of the acceleration sensor. Thereby, the monitoring unit 45 can identify from which nut looseness detector 70 the detection value of the acceleration sensor received from the nut looseness detector 70 is received.

In the example of the second embodiment, it is predetermined in which tire position each of the nut looseness detectors 70 should be arranged. More specifically, for example, the surface of the nut looseness detector 71 is provided with tire position information indicating "first rear row, right side". The tire position information may be attached in advance by the manufacturer of the nut looseness detector 71, or the user may determine the tire position to be arranged for each nut looseness detector 70 by himself/herself. Thus, each nut looseness detector 70 is associated with the tire position.

After determining the combination of the nut looseness detector 70 and the tire detector 30 by the method described in the first embodiment, the monitoring unit 45 monitors the tire position information and the tire detection information linked to the nut looseness detector 70. The container 30 can be linked. This allows the monitoring unit 45 to display the tire position of the tire detector 30 to the user.

Here, the advantage of linking the tire position to the nut looseness detector 70 will be described. Since the tire detector 30 is attached inside the tire Tr, when the tire is rotated, the axle Ax attached together with the tire Tr changes. On the other hand, as shown in FIG. 23, the nut cap 241 to which the nut looseness detector 70 is attached and the nut NW to which the nut looseness detector 70 can be attached can be easily removed from the bolt BT. Therefore, the user can remove the nut looseness detector 70 before tire rotation, and reattach the nut looseness detector 70 again after tire rotation so as to correspond to the same axle Ax. is. Thus, the nut looseness detector 70 is attached to the tire position indicated on the surface of the nut looseness detector 70 before and after tire rotation.

As described above, in the tire position determination system of Embodiment 2, the tire position is tied to the easily removable nut looseness detector 70 instead of the axle detector 15, and the tire position of the tire detector 30 is determined based on the tire position. Tire position can be determined.

The timing at which nut looseness detector 70 and tire detector 30 transmit the detection value of the acceleration sensor is not limited to arbitrary timing when vehicle 10 is stopped. Nut looseness detector 70 and tire detector 30 are, for example, based on the reception of a specific signal from another device, so that nut looseness detector 70 and tire detector 30 all transmit at the same timing. may be configured. The specific signal received from other equipment may be, for example, a trigger signal received from monitoring unit 45 or a synchronization signal received from a communication satellite.

In one aspect, the tire position determination system of Embodiment 2 may include axle detector 15 in addition to nut looseness detector 70 and tire detector 30 . In this case, the monitoring unit 45 can determine the tire position of the tire detector 30 and the tire position of the nut looseness detector 70 based on the tire position of the axle detector 15 . That is, the monitoring unit 45 detects a combination of the three configurations of the axle detector 15, the tire detector 30, and the nut looseness detector 70, which are attached to rotating bodies that rotate synchronously. Thereby, the monitoring unit 45 can determine which nut NW of the tire Tr corresponding to which axle Ax each of the nut looseness detectors 70 is attached.

In another aspect, the second embodiment may include nut looseness detector 70 and axle detector 15 without including tire detector 30 . In this case, the monitoring unit 45 can determine the tire position of the nut looseness detector 70 based on the tire position of the axle detector 15 .

Thus, in the present embodiment, the objects to be combined are not limited to two objects such as the tire detector 30 and the nut looseness detector 70. Three objects can be one combination. Hereinafter, the axle detector 15, the tire detector 30, and the nut looseness detector 70 are collectively referred to as "detectors." In addition, one unit of a plurality of detectors attached to rotating bodies that rotate synchronously is collectively referred to as a "group". In the example of Embodiment 2, the total number of groups is the same as the number of axles Ax. That is, the total number of groups is six. An example in which one group includes a plurality of detectors will be described below.

[Modification 1 of Embodiment 2]
In the second embodiment described above, an example in which one nut looseness detector 70 is provided for one axle Ax has been described. As shown in FIG. 3, multiple nuts NW are attached to one wheel WH. Modification 1 of Embodiment 2 describes a configuration in which a plurality of nut looseness detectors 70 are attached to one axle Ax.

FIG. 24 is a diagram for explaining that a plurality of nut looseness detectors 70 are attached to one axle Ax. FIG. 24 shows a view of the tire 22b viewed from the positive side of the Y axis. As shown in FIG. 24, in Modification 1 of Embodiment 2, nut looseness detector 71a and nut looseness detector 71b are attached to axle R2 corresponding to tire 22b. In Modification 1 of Embodiment 2, two nut looseness detectors 70 are similarly attached to the other axle Ax. In Modified Example 1 of Embodiment 2, the nut looseness detector 71b is an example of the "second rotating body detector" in the present disclosure.

Monitoring unit 45 can detect that nut looseness detector 71a, nut looseness detector 71b, and tire detector 32b are included in the same group by the method described in the first embodiment. Furthermore, the monitoring unit 45 can also detect that the group includes the tire detector 32a in addition to the tire detector 32b by receiving the detection value of the acceleration sensor from the tire detector 32a. Further, when the axle detector 16b is attached to the axle R2, the monitoring unit 45 can also detect that the axle detector 16b is included in the group based on the detection value of the acceleration sensor of the axle detector 16b.

That is, the monitoring unit 45 detects that all of the five detectors, ie, the nut looseness detectors 71a, 71b, the tire detectors 32a, 32b, and the axle detector 16b, are attached to a rotating body that rotates synchronously. can do. In the tire position determination system in Modification 1 of Embodiment 2, even if one group includes a plurality of detectors such that a plurality of nut looseness detectors 70 are attached to one axle Ax, , it is possible to determine which group each detector belongs to.

The number of nut looseness detectors 70 attached to one wheel as shown in FIG. 24 is not limited to two. For example, nut looseness detectors 71a to 71h may be attached to all eight nuts NW shown in FIG. In this case, one group may contain 11 detectors. Note that the number of detectors included in one group can be more than 11, such as when more nuts NW than shown in FIG. 24 are attached.

[Modification 2 of Embodiment 2]
In Modification 1 of Embodiment 2 described above, it was explained that there are as many groups as there are axles Ax, and that one group can include a plurality of detectors. Modification 2 of Embodiment 2 describes a method of determining whether or not detectors are appropriately included in each group. Specifically, the monitoring unit 45 in Modification 2 of Embodiment 2 detects that the mounting position of the nut looseness detector 70 is incorrect.

In the example of FIG. 24, two nut looseness detectors 71a and 71b are attached to one wheel. Two nut looseness detectors 70 are similarly attached to the other axle Ax. That is, in Modification 2 of Embodiment 2, it is predetermined that two nut looseness detectors 70 are included in the same group for one axle detector 15 .

In this way, when the number of nut looseness detectors 70 attached to one axle detector 15 is predetermined, in Modification 2 of Embodiment 2, the number of nuts different from the predetermined number is determined. An error in the mounting position of the nut looseness detector 70 is detected depending on whether or not the looseness detector 70 is included in one group.

For example, assume that monitoring unit 45 determines that only nut looseness detector 71a of nut looseness detectors 70 is included in the group that includes axle detector 16b for axle R2. In this case, the monitoring unit 45 detects only one nut looseness detector 70 even though two nut looseness detectors 70 should be attached to the axle detector 16b. It is detected that the device 71b is attached to the wheel WH of another tire Tr or has fallen off.

More specifically, if another group includes three nut looseness detectors 70, the monitoring unit 45 displays to the user that the mounting position of the nut looseness detectors 70 is incorrect, and all groups If the total number of nut looseness detectors 70 is less than 12, it is displayed to the user that some of the nut looseness detectors 70 may have fallen off. Thus, in the second modification of the second embodiment, by predetermining the number of nut looseness detectors 70 included in one group, errors in the mounting position of the nut looseness detectors 70 and from the wheel WH It is possible to detect the loss of the nut looseness detector 70 due to falling off of the nut. In other words, the monitoring unit 45 determines whether or not the number of rotating bodies rotating in synchronism with the tires Tr matches a predetermined number.

[Embodiment 3]
In the first embodiment, the position of the tire Tr to which the tire detector 30 is attached is determined by acquiring the combination of the axle detector 15 attached to the axle Ax and the tire detector 30 attached to the tire Tr. A tire position determination system has been described. In Embodiment 3, a rotating body position determination system that detects a combination of rotating bodies using a nut looseness detector instead of the tire detector 30 will be described. In the third embodiment, descriptions of configurations overlapping those of the first and second embodiments will not be repeated.

The rotating body position determination system of Embodiment 3 does not include tire detector 30 , but includes only nut looseness detector 70 and axle detector 15 . In the example of Embodiment 3, as in Embodiment 2, one nut looseness detector is provided for one axle Ax. That is, since vehicle 10 in Embodiment 3 has six axles Ax, vehicle 10 is similarly provided with six nut looseness detectors.

As described above, the monitoring unit 45 of Embodiment 1 specified the position of the tire detector 30 with reference to the position of the axle detector 15 . The monitoring unit 45 of Embodiment 2 specified the position of the tire detector 30 with reference to the position of the nut looseness detector 70 . In the example of Embodiment 3, the monitoring unit 45 identifies the position of the nut looseness detector 70 with reference to the position of the axle detector 15 .

In the third embodiment, tire position information is not attached to the surface of the nut looseness detector 70 as in the second embodiment. In other words, the monitoring unit 45 cannot specify the tire position based on the information received from the nut looseness detector 70 . The monitoring unit 45 of the third embodiment detects the position of the nut looseness detector 70 based on the position of the axle detector 15 by combining the axle detector 15 fixed to the axle Ax and the nut looseness detector 70. Identify. The monitoring unit 45 of Embodiment 3 determines the mounting position of the axle detector 15 based on the identifier received from the axle detector 15 . That is, the monitoring unit 45 determines whether or not the axle detector 15 and the nut looseness detector 70 rotate synchronously, thereby determining the attachment position and the nut based on the identifier received from the axle detector 15. The position of the nut looseness detector 70 is identified by matching it with the looseness detector 70 . Thereby, the monitoring unit 45 of Embodiment 3 can detect at which position the nut looseness detector 70 is attached.

In addition, the monitoring unit 45 of the third embodiment is a modification of the second embodiment when, for example, one axle detector 15 is combined with a number of nut looseness detectors 70 different from the predetermined number. As in Example 2, it is displayed to the user that the mounting position of the nut looseness detector 70 is incorrect, or that part of the nut looseness detector 70 may have fallen off. Thereby, in Embodiment 3, the nut looseness detector 70 can be appropriately managed.

In Embodiment 3, the axle detector 16b may correspond to the "third rotating body detector" in the present disclosure. In Embodiment 3, referring to FIGS. 1 and 23, nut looseness detector 71 attached to a position corresponding to axle detector 16b corresponds to the "fourth rotating body detector" in the present disclosure. can. Further, the nut looseness detector 70 other than the nut looseness detector 71 in the third embodiment can correspond to the "fifth rotating body detector" in the present disclosure.

[Embodiment 4]
In Embodiments 1 to 3, configurations in which at least a plurality of detectors are included in one group have been described. For example, in the second embodiment, a configuration in which tire detector 30 and nut looseness detector 70 are included in one group has been described. In Embodiment 4, an example will be described in which tire detector 30 is removed from the configuration of Embodiment 2, and nut looseness detector 70 is the only detector included in one group. In the fourth embodiment, the description of the configuration overlapping with that of the second embodiment will not be repeated.

Referring to FIG. 1, vehicle 10 according to the fourth embodiment includes front axles F1 and F2 and tires 11 and 12, and rear axles R1 and R2 and tires 21b and 22b. That is, the vehicle 10 according to Embodiment 4 has a configuration obtained by removing the axles R3, R4 and the tires 23, 24, 21a, 22a from the vehicle 10 shown in FIG. In short, the vehicle 10 of Embodiment 4 is a vehicle provided with four axles Ax and tires Tr.

The rotating body position determination system according to Embodiment 4 does not include tire detector 30 and axle detector 15, but includes only four nut looseness detectors 70 as detectors. It is predetermined that each of the four nut looseness detectors 70 is attached to each of the tires 11, 12, 21b, 22b. The monitoring unit 45 according to the fourth embodiment acquires the acceleration detection value of each of the four nut looseness detectors 70 . The monitoring unit 45 uses the method described in the first embodiment to determine whether or not there is a nut looseness detector 70 that can be combined among the four nut looseness detectors 70 .

When the monitoring unit 45 detects a nut looseness detector 70 that can be combined among each of the four nut looseness detectors 70, the monitoring unit 45 displays to the user that the mounting position of the nut looseness detector 70 is incorrect. . When nut looseness detectors 70 that can be combined are detected, it means that a plurality of nut looseness detectors 70 are included in one group. The four nut looseness detectors 70 are not attached to the tires 11, 12, 21b, and 22b, respectively. In this case, the vehicle 10 has a plurality of nut looseness detectors 70 attached to one tire Tr. It will be in a state where

For example, two nut looseness detectors 70 are attached to tire 11, one nut looseness detector 70 is attached to tire 12, one nut looseness detector 70 is attached to tire 21b, and nut looseness detection is performed to tire 22b. A state in which the device 70 is not attached may correspond. Therefore, the monitoring unit 45 in the fourth embodiment displays to the user that the nut looseness detector 70 is attached to an incorrect attachment position that is not the predetermined attachment position. On the other hand, when the nut looseness detector 70 that can be combined is not detected, the monitoring unit 45 in the fourth embodiment can display to the user that there is no abnormality in the mounting position of the nut looseness detector 70. .

As a result, in the rotating body position determination system of the fourth embodiment, when each nut looseness detector 70 is not combined with another nut looseness detector 70, the nut looseness detector can be appropriately installed at a predetermined mounting location. 70 is attached. In the fourth embodiment, the configuration in which only one detector is included in the group using the nut looseness detector 70 has been described, but the one detector included in the group is not the nut looseness detector 70. It may be the tire detector 30 or the axle detector 15 .

[Common Modification in Embodiments 1 to 4]
In FIG. 4, it has been explained that the detection direction D3 of the tire detector 30 is the rotation radial direction D3 orthogonal to the rotation axis direction D1 of the tire Tr. However, the detection direction D3 of the tire detector 30 is not limited to the rotational radial direction D3 orthogonal to the rotational axis direction D1, and may be any direction as long as it intersects the rotational axis direction D1. That is, the detection direction D3 may be a direction inclined from the rotation axis direction D1, and may be a direction intersecting the XY plane in FIG.

That is, the acceleration in the direction intersecting with the rotation axis direction D1 includes at least a component in the rotation radial direction D3. Therefore, by extracting the component in the radial direction D3 of rotation from the acceleration in the direction intersecting with the axial direction D1, the tire detector 30 can detect the acceleration in the radial direction D3 of rotation. As a result, the tire detector 30 can transmit the detection value of the acceleration generated in the rotational radial direction D<b>3 to the monitoring unit 45 .

In the nut looseness detector 70 and the axle detector 15 as well, the direction in which acceleration is detected may be any direction that includes at least a direction component to be detected. Further, instead of all of the nut looseness detector 70, the axle detector 15, and the tire detector 30 included in the vehicle 10 detecting the acceleration in the direction intersecting the rotation axis direction D1, the nut looseness detector 70, the axle At least one of the detector 15 and the tire detector 30 may detect acceleration in a direction intersecting with the rotational axis direction D1.

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.

(Section 1) A tire position determination system according to an aspect of the present disclosure is provided in a vehicle provided with a first rotating body that rotates in synchronization with any one of a plurality of tires including a first tire. judgment system. The tire position determination system includes a first tire detector, a rotating body detector, and a monitoring unit. The first tire detector is attached to the first tire and detects acceleration applied in a direction crossing the axial direction of the rotation shaft of the first tire. The rotating body detector is attached to the first rotating body and detects acceleration applied in a direction crossing the axial direction of the rotation axis of the first rotating body. The monitoring unit is configured to receive information from the first tire detector and the rotating body detector. The monitoring unit acquires a first correspondence relationship indicating a relationship between a first value based on the detection value of the first tire detector and a second value based on the detection value of the rotating body detector in the first period; Acquiring a second correspondence indicating a relationship between a third value based on the detection value of the first tire detector and a fourth value based on the detection value of the rotating body detector in the period, and acquiring the first correspondence and the second correspondence The result of the comparison with the relationship is used to determine whether the first tire rotates in synchronism with the first rotating body.

According to the above aspect, it is determined whether or not the correspondence relationship between the rotation angle of the rotating body and the rotation angle of the first tire during the first stop period has changed during the second stop period. Thereby, it is possible to determine whether or not the first tire rotates in synchronization with the first rotating body, and to determine the tire attached to the rotating body.

(Section 2) In the tire position determination system according to Section 1, the first period and the second period are periods during which the vehicle is stopped, and the first period is a period different from the second period.

According to the above aspect, the detection values of each axle detector 15 and each tire detector 30 can be synchronized without providing an initiator or a timer for time synchronization.

(Section 3) In the tire position determination system according to Section 1 or 2, the first value and the third value are the rotation angle of the first tire estimated using the detection value of the first tire detector. and the second value and the fourth value are the rotation angles of the first rotating body estimated using the detection values of the rotating body detector.

According to the above aspect, the rotation angle of the first tire and the rotation angle of the first rotor are estimated using the detection value of the acceleration sensor for each stop period, and the estimated rotation angle of the first tire and the first rotation angle are estimated. Correspondence can be acquired using the rotation angle of the rotating body.

(Item 4) The tire position determination system according to item 1 or 2 further includes an input section connected to the monitoring unit. The input unit receives input of information about the first correspondence.

According to the above aspect, comparison processing can be performed based on the detection value of the acceleration sensor 39 during one stop period, and the time required to obtain the comparison result can be shortened.

(Item 5) In the tire position determination system according to items 1 to 4, the first rotating body is an axle attached to the first tire.

According to the above aspect, the tire position of the tire detector 30 can be determined based on the tire position to which the axle Ax is attached.

(Section 6) In the tire position determination system according to Section 5, the first rotating body has a first end surface exposed when the first rotating body is attached to the vehicle, and the rotating body detector includes , mounted on the first end face.

According to the above aspect, the axle detector 15 can be easily attached.

(Item 7) In the tire position determination system according to items 1 to 4, the first rotating body is a fastening member that fastens the wheel of the first tire and another member.

According to the above aspect, the tire position of the tire detector 30 can be determined based on the tire position to which the nut NW, which is the fastening member, is attached.

(Section 8) In the tire position determination system according to Section 7, the monitoring unit determines the mounting position of the rotating body detector based on the identifier received from the rotating body detector.

According to the above aspect, the tire position of the tire detector 30 can be determined based on the tire position information tied to the nut looseness detector 70 .

(Section 9) In the tire position determination system according to Section 7 or 8, a second rotating body that rotates in synchronization with one of the plurality of tires, and attached to the second rotating body, It further comprises a second body of rotation detector that detects acceleration applied in a direction intersecting with the axial direction of the rotation axis of the second body of rotation.

According to the above aspect, a plurality of nut looseness detectors 70 and tire detectors 30 can be combined.

(Item 10) In the tire position determination system according to Item 9, the monitoring unit determines whether or not the number of rotating bodies rotating in synchronization with the first tire matches a predetermined number.

According to the above aspect, the number of detectors to be included in the group can be used to determine whether the detectors are attached incorrectly or lost due to falling off or the like.

(Item 11) In the tire position determination system according to items 1 to 10, the first tire detector detects acceleration of the first tire in a direction perpendicular to the rotational axis direction.

According to the above aspect, the detection direction of the tire detector may be any direction as long as it includes a desired detection direction component.

(Item 12) In the tire position determination system according to items 1 to 11, the rotating body detector detects acceleration in a direction perpendicular to the rotation axis direction of the first rotating body.

According to the above aspect, the detection direction of the rotating body detector may be any direction as long as it includes a component of the desired detection direction.

(Item 13) In the tire position determination system according to items 1 to 12, it is attached to a second tire different from the first tire, and detects acceleration applied in a direction intersecting the axial direction of the rotation axis of the second tire. and a second tire detector. The monitoring unit acquires a third correspondence relationship indicating a relationship between a value based on the value detected by the second tire detector and a value based on the value detected by the rotating body detector in the first period, and acquires a third correspondence relationship in the second period. , obtaining a fourth correspondence indicating a relationship between a value based on the value detected by the second tire detector and a value based on the value detected by the rotating body detector, and comparing the third correspondence with the fourth correspondence Based on the results obtained, it is determined whether or not the second tire rotates in synchronization with the first rotating body.

According to the above aspect, it is possible to determine the tire attached to each axle in the vehicle 10 including a plurality of tires and axles.

(Item 14) In the tire position determination system according to Item 13, the second tire detector detects acceleration in a direction perpendicular to the rotation axis direction of the second tire.

According to the above aspect, the detection direction of the second tire detector may be any direction as long as it includes a desired detection direction component.

(Section 15) A rotating body position determination system provided in a vehicle provided with a third rotating body and a fourth rotating body that rotate in synchronization with one of a plurality of tires. The rotating body position determination system includes: a third rotating body detector attached to the third rotating body for detecting acceleration applied in a direction intersecting the axial direction of the rotation axis of the third rotating body; , a fourth rotating body detector that detects acceleration applied in a direction intersecting the axial direction of the rotation axis of the fourth rotating body, and information from the third rotating body detector and the fourth rotating body detector can be received. and a monitoring unit. The monitoring unit determines the mounting position of the third rotating body detector based on the identifier received from the third rotating body detector, and calculates a first value based on the detection value of the third rotating body detector in the first period, and Obtaining a first correspondence indicating a relationship between a value detected by the fourth body of rotation detector and a second value based on the value detected by the fourth body of rotation detector, and obtaining a third value based on the value detected by the body of rotation detector and the fourth rotation in the second period A second correspondence indicating a relationship with a fourth value based on the detection value of the body detector is obtained, and the result of comparing the first correspondence and the second correspondence is used to determine the third rotating body and the fourth rotating body. Determines whether or not the body rotates in synchronism with the body.

According to the above aspect, the position of the fourth rotor can be detected with reference to the mounting position of the third rotor.

(Section 16) In the rotor position determination system according to Section 15, the monitoring unit determines whether or not the number of rotors rotating in synchronization with the third rotor matches a predetermined number. .

According to the above aspect, it is possible to appropriately manage the detectors by judging whether the detectors are attached incorrectly or lost due to falling off or the like from the number of combined detectors.

(Item 17) In the rotating body position determination system according to Item 15 or 16, a fifth rotating body that rotates in synchronization with one of the plurality of tires, and a fifth rotating body attached to the fifth rotating body and a fifth rotating body detector for detecting acceleration applied in a direction crossing the axial direction of the rotation axis of the fifth rotating body.

According to the above aspect, a plurality of nut looseness detectors 70 and axle detectors 15 can be combined.

1h to 12h arrangement 10 vehicle 11, 12, 21a to 24 tires 13, 14, 31a, 31b to 34a, 34b tire detectors 15a to 17b axle detectors 21 to 24 double tires 35 controller 36, 46 storage unit, 37, 47 processing unit, 38 pressure sensor, 39 acceleration sensor, 40 receiver, 45 monitoring unit, 52 display unit, 53 input unit, A1, A2 antenna, Ar1 rotation axis, F1, F2, R1 to R4 Axle, BT bolt, CP1 center point, CT transmission circuit, D1 rotation axis direction, D2 rotation circumferential direction, D3 rotation radial direction, FP plane part, FP2 end face, FR direction, H2 hub, NIN inner nut, NW wheel nut, P Tire pressure, WH wheel.

Claims (17)

A tire position determination system provided in a vehicle provided with a first rotating body that rotates in synchronization with any one of a plurality of tires including a first tire,
a first tire detector attached to the first tire for detecting acceleration applied in a direction crossing the axial direction of the rotation shaft of the first tire;
a rotating body detector that is attached to the first rotating body and detects acceleration applied in a direction that intersects the axial direction of the rotation axis of the first rotating body;
a monitoring unit configured to receive information from the first tire detector and the rotating body detector;
The monitoring unit is
Acquiring a first correspondence relationship indicating a relationship between a first value based on the detection value of the first tire detector and a second value based on the detection value of the rotating body detector in a first period;
obtaining a second correspondence indicating the relationship between a third value based on the detection value of the first tire detector and a fourth value based on the detection value of the rotating body detector in a second period;
A tire position determination system that determines whether or not the first tire rotates in synchronization with the first rotating body using a result of comparing the first correspondence and the second correspondence. The first period and the second period are periods during which the vehicle is stopped,
The tire position determination system according to claim 1, wherein said first period is a stop period different from said second period. The first value and the third value are rotation angles of the first tire estimated using the detection value of the first tire detector,
2. The tire position determination system according to claim 1, wherein said second value and said fourth value are rotation angles of said first rotating body estimated using detection values of said rotating body detector. further comprising an input unit connected to the monitoring unit;
2. The tire position determination system according to claim 1, wherein said input unit receives input of information relating to said first correspondence. The tire position determination system according to claim 1, wherein said first rotating body is an axle to which said first tire is attached. the first rotating body has a first end surface exposed when the first rotating body is attached to the vehicle;
6. The tire position determination system of claim 5, wherein the rotating body detector is mounted on the first end surface. The tire position determination system according to claim 1, wherein the first rotating body is a fastening member that fastens the wheel of the first tire and another member. 8. The tire position determination system of claim 7, wherein the monitoring unit determines the mounting position of the rotating body detector based on the identifier received from the rotating body detector. a second rotating body that rotates in synchronization with any one of the plurality of tires;
The tire position determination according to claim 7, further comprising a second rotating body detector attached to said second rotating body and detecting acceleration applied in a direction intersecting with the axial direction of the rotation axis of said second rotating body. system. 10. The tire position determination system according to claim 9, wherein said monitoring unit determines whether or not the number of rotating bodies rotating in synchronization with said first tire matches a predetermined number. 2. The tire position determination system according to claim 1, wherein said first tire detector detects acceleration in a direction orthogonal to a rotation axis direction of said first tire. 2. The tire position determination system according to claim 1, wherein said body of rotation detector detects acceleration in a direction perpendicular to the direction of the axis of rotation of said first body of rotation. Further comprising a second tire detector attached to a second tire different from the first tire and detecting acceleration applied in a direction intersecting with the axial direction of the rotation axis of the second tire,
The monitoring unit is
Acquiring a third correspondence indicating a relationship between a value based on the value detected by the second tire detector and a value based on the value detected by the rotating body detector in the first period;
Acquiring a fourth correspondence relationship indicating a relationship between a value based on the value detected by the second tire detector and a value based on the value detected by the rotating body detector in the second period;
Claims 1 to 12, wherein it is determined whether or not the second tire rotates in synchronization with the first rotating body, using a result of comparing the third correspondence relationship and the fourth correspondence relationship. The tire position determination system according to any one of Claims 1 to 3. 14. The tire position determination system according to claim 13, wherein said second tire detector detects acceleration applied in a direction intersecting with the axial direction of the rotation axis of said second tire. A rotating body position determination system provided in a vehicle provided with a third rotating body and a fourth rotating body that rotate in synchronization with one of a plurality of tires,
a third rotating body detector attached to the third rotating body for detecting acceleration applied in a direction intersecting with the axial direction of the rotation axis of the third rotating body;
a fourth rotating body detector attached to the fourth rotating body for detecting acceleration applied in a direction intersecting with the axial direction of the rotation axis of the fourth rotating body;
a monitoring unit configured to receive information from the third rotating body detector and the fourth rotating body detector;
The monitoring unit is
determining the mounting position of the third rotating body detector based on the identifier received from the third rotating body detector;
Acquiring a first correspondence relationship indicating a relationship between a first value based on the detection value of the third body of rotation detector and a second value based on the detection value of the fourth body of rotation detector in a first period;
Acquiring a second correspondence relationship indicating a relationship between a third value based on the detection value of the third body of rotation detector and a fourth value based on the detection value of the fourth body of rotation detector in a second period;
A rotating body position determination system that determines whether or not the third rotating body and the fourth rotating body rotate synchronously using a result of comparing the first correspondence relationship and the second correspondence relationship. . 16. The rotating body position determination system according to claim 15, wherein said monitoring unit determines whether or not the number of rotating bodies rotating in synchronization with said third rotating body matches a predetermined number. a fifth rotating body that rotates in synchronization with any one of the plurality of tires;
17. The fifth rotating body detector according to claim 15, further comprising a fifth rotating body detector attached to the fifth rotating body and detecting acceleration applied in a direction intersecting with the axial direction of the rotation axis of the fifth rotating body. rotating body position determination system.

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