JP2009202675A - Irregular pneumatic tire pressure detecting device - Google Patents

Abstract

The present invention relates to a tire air pressure abnormality detection device, which is intended to automatically change a tire air pressure threshold after completion of pressure regulation in tire rotation or replacement.
Whether or not tire pressure adjustment has been performed based on a detection result of a valve core opening / closing detecting means for detecting that a valve core opening / closing operation provided to adjust tire air pressure in each wheel is performed. When it is determined that the tire pressure adjustment has been performed, a tire air pressure threshold is set for each wheel. Based on the comparison result between the detected tire pressure and the set threshold value, an abnormality in the tire pressure of the wheel attached to the vehicle is detected.
[Selection] Figure 5

Description

  The present invention relates to a tire air pressure abnormality detection device, and more particularly to a tire air pressure abnormality detection device suitable for detecting an abnormality of a wheel tire air pressure using a threshold value that differs for each wheel.

2. Description of the Related Art Conventionally, there is known a tire air pressure abnormality detection device that detects an abnormality in tire air pressure in each wheel of a vehicle (see, for example, Patent Document 1). This device has a sensor for detecting the tire air pressure for each wheel, and an initialization switch that is pressed by a dealer or a driver after tire rotation or replacement. In such an apparatus, a first determination value related to the tire pressure when the initialization switch is pressed while the tire pressure is increased from the reference pressure, and then the initialization is performed in a state where the tire pressure is reduced to the reference pressure. Based on the second determination value related to the tire pressure when the switch is pressed, a threshold value for the tire pressure is set. Then, the tire air pressure during normal driving of the vehicle is monitored, and if the tire air pressure is equal to or higher than the threshold, an abnormality in the tire air pressure is warned. Therefore, according to the above-described apparatus, it is possible to set a tire air pressure threshold value by pressing the initialization switch by a driver or the like, and to detect a tire air pressure abnormality using the threshold value.
JP 2005-193712 A

  However, in the apparatus described in Patent Document 1 described above, it is necessary for a person to turn on the initialization switch when setting the threshold value of the tire air pressure. In this respect, since the tire air pressure threshold is not set unless the initialization switch is turned on by a person, the timing for setting the tire air pressure threshold due to forgetting to press the initialization switch or the like is desired. Specifically, the threshold value may not be changed when tire rotation or replacement is performed or immediately after that.

  In general, some vehicles have different tire air pressure thresholds for each wheel mounting position (front wheel and rear wheel). For this reason, if the threshold value for each wheel is not immediately changed when the tire pressure is adjusted during tire rotation or the like, there is a risk of erroneous detection of tire pressure abnormality.

  The present invention has been made in view of the above points, and provides a tire pressure abnormality detection device capable of automatically changing a threshold value of tire pressure after completion of pressure adjustment in tire rotation, replacement, or the like. With the goal.

  The purpose of the above is to determine whether or not the tire pressure adjustment of the wheels of the vehicle has been performed, and for each wheel when it is determined by the pressure adjustment determination means that the tire pressure adjustment has been performed. Threshold value setting means for setting a tire air pressure threshold value, air pressure detection means for detecting the tire air pressure of the wheel, tire pressure detected by the air pressure detection means, and a comparison result of the threshold value set by the threshold setting means. And an abnormality detection means for detecting an abnormality in the tire air pressure of the wheel attached to the vehicle.

  In the invention of this aspect, when it is determined that the tire pressure adjustment of the wheel of the vehicle has been performed, a tire air pressure threshold is set for each wheel. In such a configuration, the tire pressure threshold value is changed every time the tire pressure adjustment is performed, and thus the threshold value change is automatically realized following the tire pressure adjustment. Is prevented.

  In the tire pressure abnormality detection device described above, the pressure adjustment determination means determines that tire pressure adjustment has been performed when tire air flows in and out on a plurality of predetermined wheels within a predetermined time. do it.

  Generally, tire pressure adjustment by tire rotation or replacement does not require much time, and is often completed within a short time. Therefore, according to such a configuration, it is possible to accurately determine whether or not the tire pressure adjustment has been performed.

  In the tire air pressure abnormality detection device described above, a valve core opening / closing detection means for detecting that the opening / closing operation of the valve core provided in each wheel has been performed is provided, and the pressure adjustment determination means includes the valve core opening / closing detection means. Based on the detection result, it may be determined whether or not the tire pressure adjustment has been performed.

  In the configuration of this aspect, if the opening / closing operation of the valve core is detected, it is possible to determine the presence / absence of the tire pressure adjustment. Therefore, it is possible to accurately determine whether or not the tire pressure adjustment has been performed. Is possible.

  In this case, the valve core opening / closing detection means detects that the valve core opening / closing operation has been performed based on an output signal of a contact sensor provided in a pore portion that contacts the tip of the valve core when the valve core is opened. What should I do?

  The valve core opening / closing detection means may detect that the opening / closing operation of the valve core has been performed based on a difference in current value flowing through the valve core.

  Further, the tire pressure abnormality detection device described above further includes an air inflow / outflow detection mechanism for detecting whether inflow of air into the tire or outflow of air from the tire is performed in each wheel, and the pressure adjustment determination described above. The means may determine whether or not tire pressure adjustment has been performed based on the detection result by the air inflow / outflow detection mechanism.

  In the configuration of this aspect, if an air inflow / outflow detection mechanism for detecting whether inflow of air into the tire or outflow of air from the tire is provided, the presence / absence of tire pressure adjustment can be determined. Therefore, it is possible to accurately determine whether or not the tire pressure adjustment has been performed.

  Further, in the tire pressure abnormality detecting device described above, the threshold value setting means determines the tire air pressure detected by the air pressure detecting means for each wheel when it is determined that the tire pressure adjustment is performed by the pressure adjustment determining means. A value reduced by a predetermined amount may be set as the threshold value.

  In this aspect of the invention, the threshold value is set based on the tire air pressure after the tire pressure adjustment determination, and therefore it is possible to set an appropriate threshold value for detecting an air pressure abnormality for each tire having different characteristics. Become.

  According to the present invention, it is possible to automatically change the threshold value of tire air pressure after completion of pressure adjustment in tire rotation, replacement, etc., thereby reliably preventing erroneous detection of tire air pressure abnormality.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a tire air pressure abnormality detection device 10 according to an embodiment of the present invention. The tire pressure abnormality detection device 10 according to the present embodiment uses a different threshold value for each wheel (left front wheel FL, right front wheel FR, left rear wheel RL, and right rear wheel RR) attached to the vehicle body. It is a device that detects abnormalities.

  As shown in FIG. 1, the tire pressure abnormality detection device 10 includes a transmitter 12 provided for each wheel of the vehicle. The transmitter 12 is installed and fixed on a rotating part such as a tire wheel that rotates when the vehicle travels, and can rotate together with the rotating part. Each transmitter 12 includes an air pressure sensor that outputs a signal corresponding to the tire pressure of the wheel, a storage unit that stores unique identification information of the wheel, and a transmission unit that wirelessly transmits data. .

  Each transmitter 12 normally transmits a data frame including tire pressure information based on the output of the air pressure sensor and unique identification information stored in the storage unit at an interval of once every predetermined time for each vehicle traveling situation through the transmission unit. Let it transmit wirelessly. For example, the above data frame is wirelessly transmitted once every 1 to 2 hours when the vehicle is stopped, and once every 1 to 2 minutes when the vehicle is traveling.

  The tire pressure abnormality detection device 10 also includes an electronic control unit (hereinafter referred to as ECU) 20 provided on the vehicle body side. The ECU 20 is mainly composed of a computer. The ECU 20 is connected to a receiving unit 22 that receives data wirelessly transmitted by the transmitting unit of the transmitter 12 described above. The data received by the receiving unit 22 is supplied to the ECU 20. When the tire air pressure information is included in the data received by the receiving unit 22, the ECU 20 associates the tire air pressure of each wheel of the vehicle with the unique identification information of the wheel based on the tire air pressure information. To detect.

  When the tire pressure is detected for each wheel, the ECU 20 monitors whether or not the tire pressure is in an abnormal state. Specifically, the ECU 20 stores in advance a correspondence relationship between wheel unique identification information (which may include a correspondence relationship with a wheel mounting position) and a tire air pressure threshold for detecting an abnormality. Part 24. When the data is received by the receiving unit 22, the tire pressure information and the unique identification information are extracted from the data, and the tire pressure is associated with the unique identification information stored in the storage unit 24. It is determined whether or not it is less than the threshold value, and a tire pressure drop abnormality is detected.

  A buzzer 26 and a warning lamp 28 are also connected to the ECU 20. The buzzer 26 is provided to give a warning sound to the vehicle driver in the vehicle, and is driven by generating a warning sound according to an instruction from the ECU 20. Further, the warning lamp 28 is provided in a combination meter or the like that can be visually recognized by a vehicle driver in the vehicle, and is driven by being lit by an instruction from the ECU 20. The ECU 20 drives the buzzer 26 and the warning lamp 28 to notify the vehicle driver of the abnormality that the tire air pressure is reduced when detecting an abnormality in the tire air pressure for any of the wheels.

  By the way, some vehicles have different tire air pressure threshold values for each vehicle mounting position. For example, the threshold value may be small for the front wheels and the threshold value may be large for the rear wheels. For this reason, if the threshold value for each wheel is not changed immediately when tire pressure adjustment is performed during tire rotation or tire replacement, that is, if the threshold value is maintained as before, There is a risk of false detection of a drop abnormality.

  Here, it is conceivable to change the threshold value of the tire air pressure of each wheel by a manual switch operation of a dealer operator or a vehicle driver after adjusting the tire pressure. However, in this method, the threshold value is not changed unless a switch operation is performed by a person. Therefore, a situation may occur in which the threshold value is not changed at an appropriate timing such as immediately after tire rotation due to forgetting to perform the switch operation. Therefore, the tire pressure abnormality detection device 10 according to the present embodiment is characterized in that the tire pressure threshold value is automatically changed immediately after the tire pressure adjustment. Hereinafter, the characteristic part of a present Example is demonstrated with reference to FIGS.

  FIG. 2 shows a cross-sectional view of the wheels of the vehicle. FIG. 3 shows a configuration diagram of a valve provided in each wheel. 3A is an external view of the valve, FIG. 3B is an external view of the valve core of the valve, and FIG. 3C is a tip of the valve core that contacts when the valve core is opened. The contact surfaces of the pores are shown respectively. FIG. 4 is a view for explaining the opening / closing operation of the valve core. FIG. 5 shows a flowchart of an example of a control routine executed by the ECU 20 to change the threshold value of the tire air pressure in this embodiment.

  In the present embodiment, each wheel is provided with a valve 30 for opening and closing a passage through which tire air flows when flowing in and out. The valve 30 has a valve core 34 that is movable in the longitudinal direction with respect to the outer cylinder 32 at the pores in the outer cylinder 32. In the normal state, the valve body 34a of the valve core 34 is seated on the valve seat of the pore portion. In this case, the above-mentioned passage is closed, and air does not flow in and out. On the other hand, when the air chuck for adjusting the tire air pressure is attached to the valve 30, the valve body 34a of the valve core 34 is separated from the valve seat of the pore portion. In this case, the passage is opened, and external air flows into the tire through the air chuck, or the air in the tire flows out through the air chuck.

  The valve core 34 has a stem 34b that extends further in the longitudinal direction from the valve body 34a in the pore portion. The stem 34b does not come into contact with the inner surface 36 of the air hole portion in the outer cylinder 32 when the tip of the stem 34b is in a normal state, that is, when the valve element 34a is seated on the valve seat. When the inflow / outflow is performed, it is configured so as to contact the inner surface 36 of the pore portion in the outer cylinder 32.

  A valve opening / closing switch 40 is disposed at the contact portion of the inner surface 36 of the pore portion of the outer cylinder 32. The valve opening / closing switch 40 is a contact sensor that detects whether or not the tip of the stem 34b of the valve core 34 is in contact with the inner surface 36 of the pore, and is turned off when the tip of the stem is not in contact with the inner surface 36 of the pore. On the other hand, the stem tip is turned on when it is in contact with the inner surface 36 of the pore portion. The valve opening / closing switch 40 is always turned on as long as an air chuck is attached to the valve 30 and air flows in and out.

  The valve opening / closing switch 40 is provided in the transmitter 12 described above. For example, after the valve opening / closing switch 40 is turned on, the transmitter 12 is, for example, a predetermined time from the turning on (specifically, generally the minimum time required to adjust the tire pressure of one wheel; for example, When the valve opening / closing switch 40 is turned off after a lapse of 1 minute), a data frame including the fact that the valve core 34 is pushed down and the unique identification information stored in the storage unit is wirelessly transmitted through the transmission unit. When the data received by the receiving unit 22 includes the fact that the valve core 34 of the wheel is pushed down, the ECU 10 pushes down the valve core 34 in the outer cylinder 32 for the wheel of the unique identification information, and opens the valve opening / closing switch 40. Detect that is turned on.

  In the above configuration, normally, the valve body 34a of the valve core 34 of the valve portion 30 is seated on the valve seat, so that the tip of the stem 34b does not contact the inner surface 36 of the pore portion in the outer cylinder 32. On the other hand, in order to adjust the tire pressure after tire rotation or tire replacement (for example, to adjust the front wheels to a relatively low tire pressure and the rear wheels to a relatively high tire pressure), a dealer operator When the air chuck is sequentially attached to each of the valves 30 of each wheel by the vehicle driver and the air flows into or out of the tire, the valve body 34a of the valve core 34 of the valve 30 is turned into a valve. By separating from the seat, the tip of the stem 34 b comes into contact with the inner surface 36 of the pore portion in the outer cylinder 32. In this case, the valve opening / closing switch 30 is activated and turned on.

  Then, when the inflow of air into the tire or the outflow of air from the tire is completed and the mounting of the air chuck to the valve 30 is released, the valve body 34a of the valve core 34 is seated on the valve seat, whereby the stem 34b The tip end of the gas pipe and the inner surface 36 of the pore portion in the outer cylinder 32 are not in contact with each other. In this case, the valve opening / closing switch 30 is inactivated and turned off.

  For example, after the valve opening / closing switch 40 has been turned on, the transmitter 12 has, for example, the valve opening / closing switch 40 after a predetermined time (minimum time required for adjusting the tire air pressure of one wheel) has elapsed since the turning on. The data including the tire pressure information based on the fact that the valve core 34 is pushed down when the valve is turned off, the output of the air pressure sensor immediately after the valve opening / closing switch 40 is turned off, and the unique identification information stored in the storage unit The frame is wirelessly transmitted from the transmission unit to the reception unit 22. This wireless transmission process is performed in the transmitter 12 of each wheel.

  The ECU 20 receives a data frame including that the above-described valve core 34 has been pushed down from all of the transmitters 12 provided on each wheel, and the valve core 34 has received the data for all the wheels having different unique identification information. It is determined whether or not the valve opening / closing switch 40 is turned on by being pushed down in the outer cylinder 32 (step 100). As a result, when it is not detected that the valve opening / closing switch 40 is turned on for all the wheels, the same processing is repeated thereafter.

  On the other hand, when it is detected that the valve opening / closing switch 40 is turned on for all the wheels, the detection of the ON state of the valve opening / closing switch 40 for all the wheels is performed for a predetermined time (specifically, In general, it is determined whether or not it has been realized within the maximum time required for adjusting the tire pressure of all the wheels (for example, 15 minutes) (step 102). As a result, when it is determined that it has not been realized within the predetermined time, the processing of step 100 is repeated thereafter. On the other hand, if it is determined that the vehicle has been realized within the predetermined time, it is determined that the tire pressure is adjusted for all the wheels of the vehicle (step 104).

  If the ECU 20 determines that the tire pressure has been regulated for all the wheels, then the ECU 20 performs a process of setting a tire pressure threshold for detecting a drop abnormality for all the wheels having different unique identification information ( Step 106). Specifically, for each wheel having different unique identification information, the tire pressure included in the data frame when the data frame including the fact that the valve core 34 transmitted from the transmitter 12 of each wheel is pushed down is received. A value corresponding to the tire pressure detected based on the information (specifically, a value obtained by reducing the tire pressure by a predetermined amount; for example, 75% of the tire pressure) is set as a tire pressure threshold. Then, for each wheel, information indicating the set tire air pressure threshold value is stored in the storage unit 24 in association with the unique identification information of the wheel.

  When the threshold value of the tire pressure is set, the ECU 20 thereafter receives the data frame including the tire pressure information from the transmitter 12 of each wheel by the receiving unit 22 and stores the wheel pressure stored in the storage unit 24. Based on the correspondence between the unique identification information and the threshold value of the tire pressure for detecting an abnormality, a process for detecting a tire pressure drop abnormality is performed. When a tire pressure drop abnormality is detected for any of the wheels, the buzzer 26 and the warning lamp 28 are driven to notify the vehicle driver that the tire air pressure has dropped.

  In such a tire pressure abnormality detection device 10, each time a wheel operator 30 or a vehicle driver or the like opens / closes the valve 30 of the wheel to adjust the tire pressure, the wheel pressure abnormality detection device 10 is automatically operated. The threshold value for detecting an abnormality in tire air pressure is changed for each. Therefore, the change of the threshold value of the tire pressure is automatically realized following the tire pressure adjustment in the tire rotation or the tire replacement without any switch operation or the like by a person, so that the threshold value change can be performed at an appropriate timing. In addition, it is possible to prevent erroneous detection of tire air pressure abnormality due to the fact that the tire air pressure threshold value is not changed after tire pressure adjustment.

  In general, tire pressure adjustment during tire rotation, tire replacement, switching between general traveling and high-speed traveling, etc. is performed for all wheels of the vehicle. In this case, not much time is required from the start to the completion of the tire pressure adjustment for all the wheels.

  On the other hand, in this embodiment, whether or not the tire pressure adjustment based on the on / off of the valve opening / closing switch 40 has been performed is determined by determining whether the stem tip of the valve core 34 is the outer cylinder for all the wheels within a predetermined time. This is done based on whether or not the tire air has flowed in and out of contact with the inner surface 36 of the pores in 32. If tire air does not flow in / out for all wheels within a predetermined time, it is not determined that tire pressure adjustment has been performed, and if tire air flows in / out for all wheels within a predetermined time. It is determined that tire pressure adjustment has been performed. Therefore, according to the configuration of the present embodiment, it is possible to accurately determine whether or not tire pressure adjustment by tire rotation or the like has been performed.

  Further, in this embodiment, when it is determined that the tire pressure adjustment is performed, the tire pressure is decreased by a predetermined amount according to the tire pressure based on the signal output from the air pressure sensor after the tire pressure adjustment is completed. A value (for example, 75% of the tire pressure) is set as the tire pressure threshold. In such a configuration, if the tire pressure adjustment of each wheel is appropriately performed, it is possible to set an appropriate threshold for detecting an abnormality in tire air pressure. Therefore, according to the present embodiment, the tire pressure threshold setting for each wheel according to the wheel mounting position can be automatically and appropriately set, and the tire resulting from the tire pressure threshold setting not being set appropriately. It is possible to prevent erroneous detection of abnormal air pressure.

  In the above embodiment, the valve opening / closing switch 40 corresponds to the “contact sensor” recited in the claims, and the ECU 20 is transmitted from the transmitter 12 of each wheel and received by the receiver 22. By detecting that the valve core 34 is pushed down and the valve opening / closing switch 40 is turned on based on the obtained data, the “valve core opening / closing detecting means” described in the claims is a step in the routine shown in FIG. By executing the process 104, the “pressure adjustment determining means” described in the claims performs the process of step 106, and the “threshold setting means” described in the claims is transmitted by each wheel. To detect the tire pressure of the wheel based on the tire pressure information included in the data transmitted from the machine 12 and received by the receiving unit 22 The "pneumatic pressure detecting means" described in the claims detects the tire pressure abnormality based on whether or not the tire pressure is less than a set threshold value. "Is realized.

  By the way, in the above-described embodiment, transmission of a data frame including that the valve core 34 is pushed down and the valve opening / closing switch 40 is turned on is performed when the valve opening / closing switch 40 is turned off thereafter. However, it may be performed when the valve opening / closing switch 40 is turned on or when a predetermined time has elapsed after being turned on.

  Further, the data frame including that the valve opening / closing switch 40 is turned on includes the detected tire pressure information based on the air pressure sensor used for setting the tire pressure threshold value after completion of the tire pressure adjustment. A data frame including the fact that 40 is turned on and a data frame including detected tire pressure information based on the air pressure sensor may be transmitted separately and independently. In this case, it is desirable to set the threshold value of the tire pressure using the detected tire pressure information received after receiving the data frame including the fact that the valve opening / closing switch 40 is turned on.

  Further, in the above embodiment, in order to detect that the opening / closing operation of the valve core 34 has been performed, the valve core 34 is provided with a stem 34b extending in the longitudinal direction from the valve body 34a within the pore portion of the outer cylinder 34. Thus, the valve opening / closing switch 40, which is a contact sensor, is disposed at a portion where the tip of the stem 34b contacts the pore inner surface 36 in the outer cylinder 32. However, the present invention is not limited to this. As shown in FIG. 6, the valve core 34 is not provided with a stem 34 b further extending from the valve body 34 a, and is located between the valve body 34 a of the valve core 34 having the same conductivity as the inner wall of the pore portion of the outer cylinder 32 having conductivity. A device for detecting a current flowing through the circuit may be provided after a circuit through which the current flows is provided.

  This current detection device includes a voltage source 50 that applies a constant voltage between the inner wall of the pore portion of the outer cylinder 32 and the valve body 34a of the valve core 34, and a current that flows in a circuit connected in series to the voltage source 50. And a current sensor 52 for detecting. In the case where the valve core 34 is closed (FIG. 6A) and the case where the valve core 34 is opened (FIG. 6B), a current flows between the inner wall of the air hole of the outer cylinder 32 and the valve body 34a of the valve core 34. The resistance at the time is different. When the valve core 34 is closed, the stem of the valve core 34 does not extend so much, so its resistance is small. On the other hand, when the valve core 34 is opened, the stem of the valve core 34 extends downward, so its resistance is large. Therefore, if the resistance of this part is detected based on the current value detected by the current sensor 52 and the magnitude of the resistance value is determined, specifically, the current value detected by the current sensor 52 is determined as that value. It is possible to detect that the opening / closing operation of the valve core 34 has been performed if the resistance of the part is wirelessly transmitted from the wheel transmitter 12 to the ECU 20 side and the resistance value is compared and determined on the ECU 20 side. It becomes.

  Further, in order to detect that the opening / closing operation of the valve core 34 has been performed, the state of distortion of the valve stem may be detected and used. The stem of the valve core 34 is distorted when an air chuck for adjusting tire air pressure is attached. Therefore, if the valve stem distortion state that is different between when the air chuck is not mounted and when the air chuck is mounted is detected and the presence / absence of the distortion is determined, specifically, the valve stem distortion state is determined by the wheel. If the transmitter 12 is wirelessly transmitted to the ECU 20 side and the ECU 20 side determines whether the valve stem is distorted or not, it can be detected that the valve core 34 has been opened and closed.

  Further, in the above-described embodiment, the determination as to whether or not the tire pressure adjustment has been performed is made based on the detection result that the valve core 34 has been opened and closed, but the present invention is not limited to this. As shown in FIG. 7, whether or not the tire pressure is adjusted by detecting the presence or absence of air flowing through the valve 30 when air flows into the tire from the outside or when air flows out from the tire to the outside. It is good also as determining.

  This modification includes an air inflow / outflow detection mechanism 70 that detects air flowing through the valve 30. The air inflow / outflow detection mechanism 70 includes a fixed portion 72 and a movable portion 74 having conductivity provided in a passage in the valve 30. The fixing portion 72 is fixed to the inner wall of the passage in the valve 30 via an insulator. The movable portion 74 is swingably supported on the inner wall of the passage in the valve 30 and swings along the flow of air in the passage (vertical direction in FIG. 7). Two movable portions 74 are provided across the fixed portion 72, and each extend in a radial direction that closes the passage. When there is no air flow in the passage in the valve 30, the fixed portion 72 and the movable portion 74 are not in contact with each other (FIG. 7A), but when air flows into the tire from the outside, the fixed portion 72 and the outside The movable portion 74 on the side contacts (FIG. 7B). On the other hand, when the air flows out from the tire, the fixed portion 72 and the movable portion 74 on the tire inner side come into contact with each other (FIG. 7C).

  A terminal S1 is connected to the fixed portion 72, and a terminal S2 is connected to the movable portion 74, respectively. The terminals S1 and S2 are disconnected when the fixed portion 72 and the movable portion 74 are not in contact with each other, and are connected when the fixed portion 72 and the movable portion 74 are in contact with each other. Therefore, if the connection state between these terminals S1 and S2 is detected, specifically, the voltage value between the terminals is wirelessly transmitted from the transmitter 12 of the wheel to the ECU 20 side, and the voltage value on the ECU 20 side. , It is possible to detect the inflow of air to the tire from the outside or the outflow of air from the tire to the outside, that is, the presence or absence of air flowing to the valve 30, and whether or not the tire pressure adjustment has been performed. It becomes possible to determine.

1 is a configuration diagram of a tire air pressure abnormality detection device according to an embodiment of the present invention. It is sectional drawing of the wheel which a vehicle has. It is a block diagram of the valve | bulb provided in each wheel. It is a figure for demonstrating the opening / closing operation | movement of a valve core. It is a flowchart of an example of the control routine performed in order to change the threshold value of a tire air pressure in a present Example. It is a figure for demonstrating operation | movement of the tire pressure abnormality detection apparatus which is a modification of this invention. It is a figure for demonstrating operation | movement of the tire pressure abnormality detection apparatus which is a modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tire pressure abnormality detection device 12 Transmitter 20 Controller 22 Receiving part 24 Storage part 30 Valve 34 Valve core 36 Pore part inner surface 40 Valve opening / closing switch

Claims (7)

A pressure adjustment determination means for determining whether or not the tire pressure adjustment of the wheel of the vehicle has been performed;
Threshold setting means for setting a tire air pressure threshold for each wheel when it is determined that the tire pressure adjustment is performed by the pressure adjustment determination means;
Air pressure detecting means for detecting the tire pressure of the wheel;
An abnormality detection means for detecting an abnormality in tire air pressure of a wheel attached to the vehicle based on a comparison result between a tire air pressure detected by the air pressure detection means and a threshold value set by the threshold value setting means;
A tire pressure abnormality detection device comprising:   2. The tire pressure abnormality according to claim 1, wherein the pressure adjustment determination unit determines that the tire pressure adjustment has been performed when tire air flows into and out of a plurality of predetermined wheels within a predetermined time. Detection device. Provided with a valve core opening / closing detection means for detecting that the opening / closing operation of the valve core provided in each wheel has been performed,
The tire pressure abnormality detection device according to claim 1, wherein the pressure adjustment determination unit determines whether or not tire pressure adjustment has been performed based on a detection result of the valve core opening / closing detection unit.   The valve core opening / closing detection means detects that the valve core opening / closing operation has been performed based on an output signal of a contact sensor provided in a pore portion that contacts the tip of the valve core when the valve core opens. The tire pressure abnormality detecting device according to claim 3, wherein   4. The tire pressure abnormality detection device according to claim 3, wherein the valve core opening / closing detection means detects that the valve core has been opened / closed based on a difference in a current value flowing through the valve core. Each wheel has an air inflow / outflow detection mechanism that detects whether inflow of air into the tire or outflow of air from the tire is performed,
The tire pressure abnormality detection device according to claim 1 or 2, wherein the pressure adjustment determination means determines whether or not tire pressure adjustment is performed based on a detection result by the air inflow / outflow detection mechanism. . The threshold setting means uses, as the threshold value, a value obtained by reducing the tire air pressure detected by the air pressure detection means for each wheel by a predetermined amount when it is determined that the tire pressure adjustment is performed by the pressure adjustment determination means. The tire pressure abnormality detection device according to any one of claims 1 to 6, wherein the tire pressure abnormality detection device is set.