JP4127206B2 - Tire and wheel information processing device - Google Patents

Description

  The present invention relates to a technique for detecting wheel state quantities, and more particularly to a tire that transmits wheel state quantities to a vehicle body and a wheel information processing apparatus that receives and processes wheel state quantities.

  In order for the vehicle to travel safely, it is essential to keep the wheels in a normal state. If the vehicle is run for a long time in a state where the tire is at a low pressure or a high temperature, the reliability of the tire is impaired, and an undesirable phenomenon is caused in some cases. Therefore, there is a demand for a technique for appropriately monitoring the air pressure, temperature and other conditions of individual tires and warning the driver early when an abnormality is detected.

  In order to know the state of each tire, a technology is known in which a sensor with a built-in transmission circuit is provided on the wheel, and the tire state quantity such as air pressure and temperature detected by the sensor is wirelessly transmitted to a receiver on the vehicle body side. (For example, refer to Patent Document 1). When the sensor is driven by a battery, if the tire state quantity is transmitted even when the vehicle is stopped, the battery is consumed quickly, and the battery needs to be replaced early. Further, the storage capacity of the battery built in the sensor can be increased or a plurality of batteries can be mounted in accordance with the long-term use of the tire, but the sensor becomes large and difficult to mount on the tire.

Therefore, it is considered that the tire state amount is transmitted only when necessary to suppress battery consumption. Patent Document 1 discloses a pneumatic sensor that detects rotation of a tire by centrifugal force, energizes a transmission circuit when the rotational speed increases and centrifugal force increases, and transmits a sensor signal. Yes.
Japanese Utility Model Publication No. 5-27644

  In the technique disclosed in Patent Document 1, since the centrifugal force does not work sufficiently during low-speed traveling, the switch is not turned on and the tire state quantity is not transmitted. Therefore, it is not possible to monitor the amount of tire condition in a situation where the vehicle is not necessarily stopped, such as when there is a traffic jam.

  The present invention has been made in view of such a situation, and an object of the present invention is to receive and process a tire that transmits a wheel state quantity to the vehicle body side at an appropriate timing according to traveling of the vehicle, and the wheel state quantity. The provision of wheel information processing devices.

  One embodiment of the present invention relates to a tire. The tire includes a grounding state detection unit that detects a grounding force to a specific location in a circumferential direction of the tire, and information on a tire state amount when the grounding force to the specific location is detected by the grounding state detection unit. And a communication device that performs transmission.

  The communication device may be integrated with a sensor that detects a tire state quantity. In addition, the communication device may have a function of only transmission for transmitting data wirelessly to a receiver on the vehicle body side, or may be driven by power from a battery.

  “Specific location in the circumferential direction of the tire” is at least one location in the circumferential direction of the tire and does not directly contact the ground, but directly from the ground. Including locations that receive ground contact. For example, a tread portion of a tire is a portion that directly contacts the ground and receives a grounding force, and a shoulder portion or a bead portion of the tire is a portion that receives a grounding force indirectly from the ground.

  According to this configuration, data transmission is performed only when a specific location in the circumferential direction of the tire receives a contact force, so that power consumption can be suppressed.

  The ground contact state detection unit may include a switch that is turned on when a ground force is input to the specific location, and the communication device may transmit information related to a tire state amount when the switch is turned on. By using the switch, it is possible to detect the grounding force to a specific location with a simple configuration.

  The switch may be a contact-type switch that is provided in tire rubber and that is turned on by mechanical contact between contacts by a grounding force to the specific location. For example, the contact type switch is turned on when two electrodes come into contact with each other by a grounding force.

  The switch may be a contactless switch that is provided in tire rubber and that is electrically turned on by a change in electrostatic capacitance due to a grounding force to the specific location. The contactless switch is configured such that, for example, the distance between two electrodes is changed by a grounding force to change the electrostatic capacity, and is turned on / off by a change in voltage between the electrodes.

  The grounding state detection unit includes a distance sensor that detects a radial distance of the tire starting from the specific location, and detects a grounding force to the specific location by a change in the distance detected by the distance sensor. Also good. “Starting from a specific location” means that the distance from the specific location as a starting point is substantially detected, and a specific location that receives a contact force and a distance sensor are provided to become an actual starting point of distance measurement. The locations need not be exactly the same location. For example, the specific location that receives contact force is the surface in contact with the ground outside the tread part of the tire, but a distance sensor is provided, and the actual starting point of distance measurement is the inside of the tire even if it is the same tread part. It is the back side. By using the distance sensor, it is possible to accurately detect the grounding force to a specific location.

  Another aspect of the present invention relates to a wheel information processing apparatus. The device includes a wheel state quantity sensor, a wheel side communication device that is provided on the wheel and transmits the wheel state amount, a vehicle body side communication device that communicates with the wheel side communication device, and an information processing that processes the wheel state amount. And a grounding state detection unit that is disposed on a wheel and detects a grounding force to a specific location in a circumferential direction of the wheel, and the wheel side communication device is configured to perform the identification by the grounding state detection unit. When the ground contact force to the location is detected, the wheel state quantity is transmitted. The wheel side communication device may have a transmission only function, and the vehicle body side communication device may have a reception only function. The wheel side communication device may be battery-driven.

  The grounding state detection unit includes a switch that is turned on when a grounding force is input to the specific location, and the wheel side communication device transmits the wheel information amount when the switch is turned on. You may stand by without transmitting while it is off. Even when the switch has been on for a long time, the wheel side communication device may perform transmission immediately after the switch is switched from off to on, and thereafter wait without performing transmission.

  According to this configuration, transmission by the wheel-side communicator is performed according to the ground contact state of a specific location in the circumferential direction of the wheel, and therefore it is possible to transmit and receive the wheel state quantity at an appropriate timing according to the traveling state of the vehicle. Become. Even during low-speed traveling, a grounding force is applied to a specific location every time the wheel rotates, and the wheel state quantity is transmitted from the wheel-side communication device. Therefore, it is possible to monitor the wheel state even during ultra-low-speed traveling such as traffic jams. In addition, the number of times a specific location receives contact force increases in proportion to the vehicle speed, and the frequency of data transmission from the wheel-side communicator increases, thus preventing a decrease in the data reception rate by radio when traveling at high speed. Can do.

  It should be noted that any combination of the above-described constituent elements and a representation of the present invention converted between a method, an apparatus, a system, and the like are also effective as an aspect of the present invention.

  According to the tire and wheel information processing apparatus of the present invention, it is possible to reliably transmit and receive the wheel state quantity at an appropriate timing according to the traveling of the vehicle.

  In describing some embodiments of the present invention, first, a basic configuration common to the embodiments will be described, and then the embodiment will be described based on the basic configuration.

  FIG. 1 is a diagram illustrating an overall configuration of a vehicle 10 including a wheel information processing device according to the basic configuration of the present invention. The vehicle 10 includes a right front wheel 20FR, a left front wheel 20FL, a right rear wheel 20RR, a left rear wheel 20RL, and a vehicle body 12. Sensor ICs 150FR, 150FL, 150RR, and 150RL that detect wheel state quantities such as air pressure and temperature are installed on the right front wheel 20FR, the left front wheel 20FL, the right rear wheel 20RR, and the left rear wheel 20RL, respectively. The sensor ICs 150FR, 150FL, 150RR, and 150RL transmit detection signals to the vehicle body 12 via the respective transmission antennas 50FR, 50FL, 50RR, and 50RL.

  The vehicle body 12 includes a receiver 62 that receives detection signals transmitted by the sensor ICs 150FR, 150FL, 150RR, and 150RL, a receiving antenna 60, and an electronic control device that collectively controls the vehicle 10 (hereinafter, “ ECU) 64, a warning buzzer 70, and a warning lamp 72 are provided. The ECU 64 grasps the wheel state based on the detection signal received from the receiver 62. When the tire temperature exceeds a predetermined value or the tire air pressure falls below a predetermined value, the ECU 64 informs the driver of the wheel state by turning on the warning lamp 72 or causing the buzzer 70 to sound a warning sound.

  Hereinafter, in order to describe the configuration without distinguishing each wheel, the symbols FR, FL, RR, and RL that distinguish the position of each wheel are omitted. Further, the right front wheel 20FR, the left front wheel 20FL, the right rear wheel 20RR, and the left rear wheel 20RL are collectively referred to as a wheel 20.

  FIG. 2 is a diagram illustrating the configuration of the sensor IC 150 of FIG. The wheel state quantity sensor 30 is installed on a tire, a wheel, a rim, or the like constituting the wheel 20 and detects a wheel state quantity. The wheel state quantity sensor 30 is, for example, an air pressure sensor that detects tire air pressure, a temperature sensor that detects the temperature of air in the tire, a temperature sensor that detects the temperature of the tire tread, an acceleration that detects the acceleration of the wheel, or the like. is there. The grounding state detection unit 100 detects the grounding state at one place in the circumferential direction of the wheel 20 and a place that can receive a grounding force from the ground by the rotation of the wheel 20 (hereinafter simply referred to as “grounding detection place”). .

  The transmitter 40 transmits the wheel state quantity detected by the wheel state quantity sensor 30 to the receiver 62 on the vehicle body 12 side via the antenna 50. The transmitter 40 is driven by the battery 42 and consumes power when transmitting data, but enters a power saving mode when in a standby state. The transmitter 40 transmits the wheel state quantity detected by the wheel state quantity sensor 30 when the grounding state detection unit 100 detects a grounding force to the grounding detection point. In other cases, the transmitter 40 is in a standby state. It is in.

  Since the transmitter 40 does not transmit the wheel state quantity while the ground detection point is not receiving the ground force, power is saved. Further, since the number of times that the ground contact detection point provided at one place in the circumferential direction of the wheel 20 receives the ground force increases in proportion to the rotational speed of the wheel 20, that is, the vehicle speed, the transmission frequency of the wheel state quantity by the transmitter 40 is increased. Will increase in proportion to the vehicle speed. That is, as the vehicle 10 travels at a higher speed, the transmission frequency of the wheel state quantity by the transmitter 40 increases, and as the vehicle speed decreases, the transmission frequency of the wheel state quantity decreases, and when the vehicle 10 stops, Since there is no rotation, the transmitter 40 does not transmit the wheel state quantity.

  Here, the wheel state quantity sensor 30 and the ground state detection unit 100 are incorporated in the sensor IC 150, and the transmitter 40, the wheel state quantity sensor 30, and the ground state detection unit 100 are integrated as an integrated circuit. Although the configuration is shown, one or both of the wheel state quantity sensor 30 and the ground state detection unit 100 may be provided outside the sensor IC 150 and connected to the sensor IC 150 by a connection line.

  Several embodiments according to the basic configuration of FIGS. 1 and 2 will be described below.

Embodiment 1
FIG. 3 is a diagram illustrating the configuration of the sensor IC 150a according to the first embodiment. In the present embodiment, a temperature sensor 30a that detects the temperature of the tire is used as an example of the wheel state quantity sensor 30, and the contact state switch 110a and the on / off state of the contact type switch 110a are used as the ground state detection unit 100. A detecting unit 120a for detecting the above is used.

  The contact switch 110a is configured such that two electrodes 112 and 114 face each other with a gap 113 therebetween. When no grounding force is input, the gap 113 is formed between the electrodes 112 and 114 by the tension of the spring 115. The two electrodes 112 and 114 are not in contact with each other and become electrically non-conductive. When the grounding force is applied, the two electrodes 112 and 114 come into contact with each other and become conductive.

  The detection unit 120a detects the conduction state of the contact switch 110a, and sends a transmission instruction signal for notifying the transmitter 40 of transmission timing when the contact type switch 110a changes from a non-conduction state to a conduction state. The transmitter 40 receives the transmission instruction signal from the detection unit 120a and transmits the temperature information detected by the temperature sensor 30a to the receiver 62.

  FIG. 4 is a diagram illustrating another configuration of the sensor IC 150a according to the first embodiment. In FIG. 3, the transmitter 40 is always driven by the battery 42 and is in the power saving mode when transmission is not performed. In the configuration of FIG. 4, the battery 42 is connected to the contact type switch 110a. When the contact switch 110a is in a non-conductive state, no power is supplied to the transmitter 40. When the contact switch 110a becomes conductive, the battery 42 is connected to the transmitter 40 and power is supplied. When the contact-type switch 110a is turned on, the transmitter 40 receives power supplied from the battery 42 and transmits temperature data detected by the temperature sensor 30a to the receiver 62.

  While the contact type switch 110a is on, power from the battery 42 is supplied to the transmitter 40. The transmitter 40 detects temperature data detected at the timing when the contact type switch 110a is switched from off to on. After that, even if the transmitter 40 receives power from the battery 42, the contact-type switch 110a remains on and operates in the power saving mode. Thereby, even if the vehicle happens to stop while the contact type switch 110a is on, the transmitter 40 does not continue to transmit temperature data.

  FIG. 5 is a diagram for explaining an installation location of the contact switch 110a and the sensor IC 150a in the sectional view of the wheel 20. As shown in FIG. The wheel 20 includes a tire 21, a wheel 22, and a rim 26. The contact type switch 110a and the sensor IC 150a are embedded at substantially the center of the tread portion 21a at one place in the circumferential direction of the tire 21. The temperature sensor 30 a included in the sensor IC 150 a measures the temperature of the tread portion 21 a of the tire 21.

  The grounding detection location P is a location in contact with the ground corresponding to the location where the contact switch 110a is embedded. This figure shows a state where the ground detection point P is not grounded, and since no contact force is applied to the contact type switch 110a, there is a gap between the two electrodes, and the contact type switch 110a is turned off. is there. While the contact type switch 110a is OFF, the sensor IC 150a does not transmit detection data from the temperature sensor 30a. In the figure, the antenna 50 for transmission is not shown.

  FIG. 6 is a diagram for explaining a state where the ground detection point P is grounded. When the tread portion 21a of the tire 21 is pressed against the ground 400, a grounding force is applied to the contact type switch 110a, there is no gap between the two electrodes, and the contact type switch 110a is turned on. At the timing when the contact switch 110a is turned on, the sensor IC 150a transmits data detected by the temperature sensor 30a to the vehicle body 12 side.

  FIGS. 7A and 7B are diagrams illustrating the contact switch 110a and the sensor IC 150a embedded in the tire 21 in different modes. In FIG. 7A, the sensor IC 150a is embedded in the shoulder portion 21b of the tire 21, and is connected to the contact type switch 110a embedded in the center of the tread portion 21a by a conductive wire. The temperature sensor 30a in the sensor IC 150a measures the temperature of the shoulder portion 21b. Also in this case, when the ground detection point P of the tire 21 is grounded, the contact switch 110a is turned on, and at that timing, the sensor IC 150a transmits the temperature data of the shoulder portion 21b detected by the temperature sensor 30a.

  In FIG. 7B, the sensor IC 150a is embedded in the bead portion 21c of the tire 21, and is connected to the contact switch 110a embedded in the center of the tread portion 21a by a conductive wire. The lead wire between the contact switch 110a and the sensor IC 150a passes through the inside of the tire 21 in the figure, but may be attached to the inner surface of the tire 21 or through the inside of the tire 21. In this case, the temperature sensor 30a in the sensor IC 150a measures the temperature of the bead portion 21c, and the contact-type switch 110a is turned on at the timing when the ground detection point P of the tire 21 is grounded, and the bead portion 21c from the sensor IC 150a. Temperature data is sent.

  As shown in FIGS. 7A and 7B, the sensor IC 150a is installed in a place suitable for the temperature sensor 30a to detect the temperature. Further, when the wheel state quantity sensor 30 is an air pressure sensor that detects the air pressure of the tire 21, a sensor IC 150a incorporating the air pressure sensor is provided, for example, in a valve, and the contact type switch 110a provided in the tread portion 21a is connected by a conductor. It is connected to the sensor IC 150a in the valve. Thus, the contact type switch 110a only needs to be provided in the tread portion 21a, and the installation location of other configurations is arbitrary. Further, when the temperature sensor 30a is provided outside the sensor IC 150a and is connected to the sensor IC 150a, the sensor IC 150a is installed in the tread portion 21a together with the contact type switch 110a, and only the temperature sensor 30a is provided in another location. Also good.

  As another installation form of the contact switch 110a and the sensor IC 150a, both the contact switch 110a and the sensor IC 150a may be provided on the shoulder portion 21b or the bead portion 21c of the tire 21. When the ground detection point P is grounded, a grounding force is directly applied to the tread portion 21a from the ground, but at the same time, the grounding force is transmitted to the shoulder portion 21b and the bead portion 21c. Therefore, you may provide the contact type switch 110a in the shoulder part 21b and the bead part 21c.

  In this case, the location of the shoulder portion 21b and the bead portion 21c where the contact switch 110a is provided is defined as a ground detection location P. The detection unit 120a detects an indirect grounding force input to the grounding detection point P provided with the contact type switch 110a based on the conduction state of the contact type switch 110a. At this time, the indirect grounding, such as making the inclination of the two electrodes of the contact type switch 110a perpendicular to the direction in which the grounding force is transmitted or making the gap between the two electrodes narrower than in the case where the bead portion 21c is provided. Adjustment is performed so that the contact-type switch 110a is reliably turned on by force.

  FIG. 8 is a flowchart showing the detection procedure of the wheel state quantity by the sensor IC 150a having the above configuration.

  The detection unit 120a detects the grounding state of the grounding detection point P of the tire 21 provided with the contact type switch 110a by detecting the conduction state of the contact type switch 110a (S10). When the grounding force to the grounding detection point P is not detected (N in S10), the detection unit 120a repeats Step S10. When the grounding force to the grounding detection point P is detected (Y in S10), the detection unit 120a sends a transmission instruction signal for notifying the transmitter 40 of the transmission timing (S11).

  When the ground detection point P comes to a position just below the wheel 20 due to the rotation of the wheel 20, the ground detection point P is grounded, and the contact type switch 110a receives the grounding force to the maximum and becomes conductive. In addition, even before the ground detection point P comes to a position just below the wheel 20, the grounding force is transmitted and the contact type switch 110a may be in a conductive state. In any case, the contact-type switch 110a is switched from the non-conductive state to the conductive state only once in one rotation of the wheel 20. At that timing, the detection unit 120a sends a transmission instruction signal to the transmitter 40. send.

  When the transmitter 40 receives the transmission instruction signal from the detection unit 120a, the transmitter 40 acquires the detection data of the wheel state quantity from the wheel state quantity sensor 30 (S12). For example, when the wheel state quantity sensor 30 is a temperature sensor 30 a provided in the tread portion 21 a of the tire 21, the temperature of the tread portion 21 a is detected and the detected data is supplied to the transmitter 40. The transmitter 40 transmits the wheel state quantity detection data supplied from the wheel state quantity sensor 30 to the receiver 62 of the vehicle body 12 via the antenna 50 (S14). The ECU 64 of the vehicle body 12 processes the received wheel state quantity.

  When the battery 42 is exhausted (Y in S16), the sensor IC 150a ends the wheel state quantity detection procedure. However, as long as the battery 42 continues to be in service (N in S16), the sensor IC 150a proceeds to step S10 for detecting the grounding by the detector 120a. Return and the subsequent processing is repeated.

  According to the tire and wheel information processing apparatus of the first embodiment, the wheel-side transmitter 40 transmits the detection data of the wheel state quantity only at the timing when the contact detection point P in the circumferential direction of the tire 21 receives the contact force. Since it transmits and does not transmit except the timing, power consumption can be suppressed. Further, as the vehicle speed of the vehicle 10 increases, the period at which the contact detection point P receives the contact force decreases, and the transmission frequency of detection data from the transmitter 40 increases. The reception state in the device 62 does not deteriorate.

Embodiment 2
FIG. 9 is a diagram illustrating the configuration of the sensor IC 150b according to the second embodiment. A different point from Embodiment 1 is demonstrated. In the present embodiment, as the ground state detection unit 100, an ultrasonic sensor 110b and a detection unit 120b that detects a ground state from an output value from the ultrasonic sensor 110b are used.

  The ultrasonic sensor 110b measures the distance to the object by transmitting ultrasonic waves to the object and receiving the reflected wave. In the present embodiment, the ultrasonic sensor 110 b is provided at the ground detection point P of the tire 21 and is used to measure the distance from the ground detection point P to the rim surface of the wheel while the vehicle 10 is traveling. The detecting unit 120b detects the grounding state of the grounding detection point P by examining the change in the distance detected by the ultrasonic sensor 110b.

  FIG. 10 is a diagram for explaining an installation location of the sensor IC 150 b in the cross-sectional view of the wheel 20. The ultrasonic sensor 110 b in the sensor IC 150 b is disposed in the center of the tread portion 21 a of the tire 21, and an ultrasonic transmitter / receiver appears inside the tire 21. The ultrasonic sensor 110b applies the ultrasonic wave 300 to the surface of the rim 26 on the tire 21 side (referred to as a rim drop or a wheel drop) and receives the reflected wave 302, thereby detecting the ground detection point P, more precisely the ground detection point. The distance H from the point on the inner surface of the tread portion 21a corresponding to P to the rim drop is measured. Since the tread portion 21a of the tire 21 is pressed against the ground 400 in the state where the ground detection point P of the tire 21 is grounded, the distance H to the rim drop is larger than the state where the ground detection point P is not grounded. Shorter.

FIG. 11 is a diagram for explaining the change over time of the distance H from the ground detection point P to the rim drop detected by the ultrasonic sensor 110b provided at the ground detection point P. FIG. The graph of the figure shows the time change of the distance H, with the horizontal axis representing time T and the vertical axis representing distance H. The distance H when the ground detection point P is not grounded is h ₀ , which is the maximum value. When the ground detection point P is grounded, the distance H decreases to h ₁ .

A threshold value h _th is set in advance between the maximum value h ₀ and the minimum value h ₁ of the measured distance H, and the detection unit 120b causes the distance H measured by the ultrasonic sensor 110b to fall to the threshold value h _th. It is determined that the contact detection point P has received a contact force. By making the threshold value h _{th of the} ground contact determination slightly larger than the minimum value h _1, it is possible to prevent the ground contact detection error at the ground contact detection point P caused by the distance measurement error or the influence of disturbance.

The detection unit 120b determines the time points t ₁ and t ₂ when the distance H has decreased to the threshold value h _th as the transmission timing of the wheel state quantity, and sends a transmission instruction signal to the transmitter 40 at the time points t ₁ and t ₂ .

In the present embodiment, the processing of the ground contact detection S10 in the wheel state quantity detection procedure in FIG. 8 is performed by detecting that the distance H detected by the ultrasonic sensor 110b is equal to or less than the threshold value _hth . Subsequent processing steps S11 to S16 are the same as those in the first embodiment.

  12A and 12B are diagrams illustrating another configuration example of the sensor IC according to the present embodiment. The sensor IC 152b shown in FIG. 12A uses an air pressure sensor 30b as an example of the wheel state quantity sensor 30, and the air pressure sensor 30b is provided outside the sensor IC 152b and connected to the sensor IC 152b with a connection line. It is a configuration. The sensor IC 154b shown in FIG. 12B similarly uses the air pressure sensor 30b, but the air pressure sensor 30b is provided inside the sensor IC 154b, while the ultrasonic sensor 110b is provided outside the sensor IC 154b and connected by a connection line. It is.

  FIG. 13 is a diagram for explaining an installation location of the sensor IC 152b of FIG. A sensor IC 152b incorporating the ultrasonic sensor 110b is provided in the center of the tread portion 21a of the tire 21. On the other hand, the air pressure sensor 30b connected to the sensor IC 152b via a connection line is provided in the valve 24 and detects the air pressure in the tire 21.

  FIG. 14 is a diagram for explaining an installation location of the sensor IC 152b of FIG. The ultrasonic sensor 110 b is provided in the center of the tread portion 21 a of the tire 21, and the sensor IC 154 b including the air pressure sensor 30 b is provided in the valve 24.

  When the tire air pressure is detected as the wheel state quantity, the tire air pressure cannot be measured even if the air pressure sensor 30b is provided in the rubber of the tire 21, and therefore the air pressure sensor 30b is installed on the inner surface of the rim 26 on the side of the tire 21. There is a need. In that case, as shown in FIG. 13 or FIG. 14, the air pressure sensor 30b may be installed in a place suitable for measuring the air pressure, and the ultrasonic sensor 110b may be installed in the rubber of the tread portion 21a.

  Further, as another modification, the installation location of the ultrasonic sensor 110b is changed, for example, the ultrasonic sensor 110b is installed at one place on the inner surface of the rim 26 on the tire 21 side, and the ultrasonic sensor 110b is connected to the tread portion of the tire 21. By applying an ultrasonic wave toward the inner surface side of 21a and receiving the reflected wave, from the point on the inner surface of the tread portion 21a corresponding to the ground detection point P, more precisely, the ground detection point P to the rim drop. The distance H may be measured.

Embodiment 3
FIG. 15 is a diagram illustrating the configuration of the sensor IC 150c according to the third embodiment. Differences from the second embodiment will be described. In the present embodiment, instead of the ultrasonic sensor 110b of the second embodiment, a reflective photointerrupter 110c capable of measuring the distance to the proximity object is used.

  The reflective photointerrupter 110c is a combination of a light emitting diode and a phototransistor in one element. The light emitting diode emits infrared light, and the phototransistor detects the reflected light, thereby measuring the distance to the object. . In the present embodiment, the reflective photo interrupter 110c is provided in the tread groove at a position corresponding to the grounding detection point P of the tire 21, and is used to detect the distance from the tread groove to the ground at the time of grounding. The detection unit 120c detects the ground state of the ground detection point P by examining the change in the distance detected by the reflective photointerrupter 110c.

  FIG. 16 is a diagram for explaining an installation location of the sensor IC 150 c in the cross-sectional view of the wheel 20. The sensor IC 150c is installed so as to face the tread groove 310 at the center of the tread portion 21a. FIG. 17 is an enlarged view of the installation location of the sensor IC 150c. The reflective photointerrupter 110c in the sensor IC 150c measures the distance D from the tread groove 310 to the ground 400 by irradiating the ground 400 with infrared rays from the tread groove 310 and receiving the reflected light. In a state where the ground contact detection point P is located directly below the wheel 20 and is substantially grounded, the height of the tread groove 310 is reduced by the ground contact force, and the distance D is shortened.

Similar to the second embodiment, the detection unit 120c examines the time change of the distance D detected by the reflective photointerrupter 110c, and when the distance D decreases to the threshold value _dth , the ground detection point P exerts the grounding force. It determines with having received, the time is determined as a transmission timing, and a transmission instruction signal is sent to the transmitter 40. Here, the threshold value d _th is set between the maximum distance d ₀ when the ground detection point P does not receive the ground force and the minimum distance d ₁ when the ground detection point P receives the maximum ground force. The Note that an ultrasonic proximity sensor may be used to measure the distance of the tread groove 310 instead of the reflective photointerrupter 110c of the present embodiment.

  In the present embodiment, the reflective photointerrupter 110c cannot detect the reflected light due to the infrared irradiation unless the ground detection point P is located near the ground 400. Therefore, the distance from the tread groove 310 to the ground 400 is always detected. Although D is not measured, if the reflected light cannot be detected sufficiently, it may be considered that the distance D is infinite. In addition, the reflective photo interrupter 110c does not necessarily measure the distance D from the tread groove 310 to the ground 400, but simply detects the presence or intensity of reflected light by infrared irradiation, thereby grounding the ground detection point P. Force may be detected. When the grounding detection point P is not receiving a grounding force, the reflected infrared light is not detected or is very weak even if detected, but the grounding detection point P is the wheel 20 As it approaches directly below, the reflected light is detected, and when the ground detection point P is located just below the wheel 20, the reflected light is the strongest. From this, the detection unit 120c checks the presence or intensity of the reflected light detected by the reflective photointerrupter 110c, and when the reflected light is detected or when reflected light having a predetermined threshold intensity or more is detected, You may determine with the earthing | grounding detection location P receiving the earthing force.

Embodiment 4
FIG. 18 is a diagram illustrating the configuration of the sensor IC 150d according to the fourth embodiment. Differences from the second embodiment will be described. The acceleration sensor 110 d is provided at the ground contact detection point P of the tire 21 and detects the radial acceleration of the tire 21. The detection unit 120d detects the grounding state of the grounding detection point P by examining the change in acceleration detected by the acceleration sensor 110d.

  FIG. 19 is a diagram for explaining an installation location of the sensor IC 150d in the cross-sectional view of the wheel 20. As shown in FIG. The acceleration sensor 110d in the sensor IC 150d is disposed in the center of the tread portion 21a and measures the acceleration in the radial direction of the tire 21. In the state where the ground contact detection point P of the tire 21 is grounded, the radius of the tire 21 is shortened by the ground contact force.

FIGS. 20A and 20B are diagrams illustrating the principle of detecting the grounding state of the grounding detection point P by the acceleration sensor 110d. FIG. 20A shows a state where the ground detection point P where the acceleration sensor 110d is provided is not grounded. Between the radial acceleration g ₀ of the tire 21 detected by the acceleration sensor 110d and the angular velocity ω of the wheel 20, the distance from the acceleration sensor 110d to the center O of the tire 21, that is, the radius of the tire 21 is r _0. , G ₀ = r ₀ × ω ² holds.

FIG. 20B shows a state where the ground detection point P is grounded. The distance to the center O of the acceleration sensor 110d and the tire 21, i.e. the radius r ₁ of the tire 21 is shorter than the radius r ₀ of the tire 21 when not grounded by the ground forces. If the angular velocity ω of the wheel 20 is constant at this time, g ₁ = r ₁ × ω ² between the radial acceleration g ₁ of the tire 21 detected by the acceleration sensor 110d and the angular velocity ω of the wheel 20. since the relation holds, the acceleration g ₁ in the radial direction of tire 21 is smaller than the state where grounding detection point P is not grounded. Therefore, the ground contact state of the ground contact detection point P can be detected from the change in the radial acceleration of the tire 21.

FIG. 21 is a diagram for explaining the time change of the radial acceleration G of the tire 21 detected by the acceleration sensor 110d provided at the ground detection point P. As shown in FIG. The graph of the figure shows time change of the acceleration G, with the horizontal axis representing time T and the vertical axis representing acceleration G. The acceleration G when the ground detection point P is not grounded is g ₀ , which is the maximum value. When ground detection position P is grounded, the acceleration G falls to g _1.

As in the second embodiment, a threshold value g _th is set in advance between the maximum value g ₀ and the minimum value g ₁ of the acceleration G to be measured, and the detection unit 120d determines that the acceleration G measured by the acceleration sensor 110d is determines the threshold g time t ₁ which fell to a _th, t ₂ at ground detection position P is subjected to ground forces, determines the time t _1, t ₂ and the transmission timing of the wheel information amount transmitted to the transmitter 40 Send an instruction signal.

  The present invention has been described based on the embodiments. The above embodiments are exemplifications, and it is understood by those skilled in the art that various modifications thereof are also included in the scope of the present invention. Examples of such modifications are given.

  The contact type switch 110a according to the first embodiment is turned on / off by mechanical contact of two electrodes, but may be a capacitive contactless switch. If a contactless switch of capacitance type is used, if the distance between two electrodes is reduced by the grounding force, the capacitance increases and the voltage between the electrodes decreases. can do. In addition, a switch that detects a grounding force by detecting expansion and contraction due to the grounding force by a voltage change using a piezoelectric element or a strain gauge may be configured.

In the fourth embodiment, the ground contact state of the ground detection point P is detected by the time change of the acceleration G detected by the acceleration sensor 110d. However, a wheel speed sensor is provided for each wheel 20, and the wheel speed sensor is The angular velocity ω may be detected, and the detection unit 120d may be configured to calculate the radius r = G / ω ² of the tire 21 using the relationship G = r × ω ² . In this case, the detection unit 120d can similarly detect the ground contact state of the ground contact detection point P from the time change of the radius r of the tire 21. In this case, it can be considered that a combination of the acceleration sensor 110d and the wheel speed sensor constitutes a distance sensor that measures the radius r of the tire 21.

  In general, when transmitting data wirelessly from a transmitter provided on a wheel to a receiver on the vehicle body, the position of the transmitter changes with the rotation of the wheel, so the transmitter on the wheel side and the receiver on the vehicle body side Depending on the positional relationship, there is a so-called “radio wave blind spot” in which the radio wave from the transmitter does not reach the receiver on the vehicle body side. In the embodiment of the present invention, the time point when the contact force to the contact detection point P is detected is determined as the transmission timing, and the detection data of the wheel state quantity is transmitted, but the contact force to the contact detection point P is detected. After that, there is a delay for a very short time between the detection of wheel state quantity detection data. Depending on the relationship between the delay in transmission timing and the vehicle speed, the transmission timing may occur when the wheel-side transmitter enters the blind spot of radio waves in a situation where the vehicle is traveling at a certain speed. In order to avoid such a situation, the transmitter on the wheel side may randomly delay the transmission start time when transmitting the detection data of the wheel state quantity after detecting the ground contact. Thereby, a random offset is added to the transmission timing, and it is possible to avoid a situation in which the detection data of the wheel state quantity is continuously transmitted at a cycle in which the transmitter enters the blind spot of the radio wave while traveling at a certain speed.

It is a figure explaining the whole structure of the vehicle provided with the wheel information processing apparatus which concerns on the basic composition of this invention. It is a figure explaining the structure of the sensor IC of FIG. FIG. 3 is a diagram illustrating a configuration of a sensor IC according to the first embodiment. It is a figure explaining another structure of the sensor IC which concerns on Embodiment 1. FIG. In the sectional view of a wheel, it is a figure explaining the installation place of the contact type switch and sensor IC concerning Embodiment 1. FIG. It is a figure explaining the state which the grounding detection location grounded. It is a figure explaining another installation location of the contact-type switch which concerns on Embodiment 1, and sensor IC. 4 is a flowchart showing a procedure for detecting a wheel state quantity by the sensor IC according to the first embodiment. It is a figure explaining the structure of the sensor IC which concerns on Embodiment 2. FIG. In the sectional view of a wheel, it is a figure explaining the installation location of sensor IC concerning Embodiment 2. FIG. It is a figure explaining the time change of the distance from the ground detection location detected by the ultrasonic sensor provided in the ground detection location to the rim drop. It is a figure explaining the other structural example of the sensor IC which concerns on Embodiment 2. FIG. It is a figure explaining the installation location of sensor IC of the composition of Drawing 12 (a) in a sectional view of a wheel. It is a figure explaining the installation location of sensor IC of the composition of Drawing 12 (b) in a sectional view of a wheel. FIG. 10 is a diagram for explaining a configuration of a sensor IC according to a third embodiment. It is a figure explaining the installation location of sensor IC concerning Embodiment 3 in a sectional view of a wheel. It is an enlarged view of the installation location of sensor IC of FIG. It is a figure explaining the structure of the sensor IC which concerns on Embodiment 4. FIG. It is a figure explaining the installation location of sensor IC in sectional drawing of a wheel. It is a figure explaining the principle by which the grounding state of a grounding detection location is detected by the acceleration sensor of FIG. It is a figure explaining the time change of the acceleration of the radial direction of the tire detected by the acceleration sensor provided in the contact detection location.

Explanation of symbols

  10 vehicle, 12 vehicle body, 20 wheel, 21 tire, 21a tread part, 21b shoulder part, 21c bead part, 22 wheel, 26 rim, 30 wheel state quantity sensor, 30a temperature sensor, 30b air pressure sensor, 40 transmitter, 42 battery , 62 receiver, 64 ECU, 70 buzzer, 72 warning lamp, 100 ground state detection unit, 110a contact type switch, 110b ultrasonic sensor, 110c reflective photo interrupter, 110d acceleration sensor, 120a-d detection unit.

Claims (12)

A contact state detection unit that detects a contact force to a specific location in the circumferential direction of the tire;
A tire comprising: a communicator that transmits information related to a tire state quantity when a contact force to the specific location is detected by the contact state detection unit.   The ground contact state detection unit includes a switch that is turned on by an input of a ground contact force to the specific location, and the communication device transmits information on the tire state amount when the switch is turned on. The tire according to claim 1.   The tire according to claim 2, wherein the switch is a contact-type switch that is provided in tire rubber and is turned on by mechanical contact between the contacts by a grounding force to the specific location.   The tire according to claim 2, wherein the switch is a contactless switch that is provided in a tire rubber and is electrically turned on by a change in electrostatic capacitance due to a grounding force to the specific location.   The ground contact state detection unit includes a distance sensor that detects a radial distance of a tire starting from the specific location, and detects a ground contact force to the specific location based on a change in the distance detected by the distance sensor. The tire according to claim 1.   The distance sensor is provided in a tread portion of a tire and measures a distance from an inner surface of the tread portion to a rim surface of the wheel, and the contact state detection unit is configured such that the measured distance is equal to or less than a predetermined threshold value. The tire according to claim 5, wherein a contact force to the specific part is detected when it becomes.   The distance sensor is provided in a tread groove of a tire and measures a distance from the tread groove to the ground, and the grounding state detection unit is configured such that when the measured distance becomes a predetermined threshold value or less, The tire according to claim 5, wherein a contact force to the specific portion is detected.   The ground contact state detection unit includes an acceleration sensor that detects a radial acceleration of a tire at the specific location, and detects a ground contact force to the specific location based on a change in acceleration detected by the acceleration sensor. The tire according to claim 1. A wheel state quantity sensor; a wheel side communication device that is provided on the wheel and transmits the wheel state quantity; a vehicle body side communication device that communicates with the wheel side communication machine; and an information processing unit that processes the wheel state quantity. In the wheel information processing device,
It is arranged on the wheel, and includes a grounding state detection unit that detects a grounding force to a specific location in the circumferential direction of the wheel,
The wheel information processing apparatus, wherein the wheel side communication device transmits the wheel state quantity when a grounding force to the specific location is detected by the grounding state detection unit. The grounding state detection unit includes a switch that is turned on by input of a grounding force to the specific location,
The wheel information according to claim 9, wherein the wheel side communication device transmits the wheel information amount when the switch is turned on, and waits without performing transmission while the switch is turned off. Processing equipment.   The ground contact state detecting unit detects a ground contact force to the specific location by a change in a detection value by a distance sensor that detects a distance in a radial direction of a wheel starting from the specific location. The wheel information processing apparatus described. 10. The wheel according to claim 9, wherein the ground contact state detection unit detects a ground contact force to the specific location by a change in a detection value by an acceleration sensor that detects acceleration in a radial direction of the wheel at the specific location. Information processing device.

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