JP3961305B2 - Tire pressure alarm device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire air pressure alarm device, and more particularly to a tire air pressure alarm device that detects a decrease in air pressure in a run-flat tire and automatically issues an alarm.
[0002]
[Prior art]
In order to ensure safe driving of the vehicle, it is necessary to always set the vehicle tire pressure to an appropriate state. For example, when the air pressure in the tire decreases, the occurrence rate of punctures increases and bursts occur at high speeds, which may cause a serious accident.
[0003]
For this reason, conventionally, various tire pressure alarm devices that detect a decrease in tire air pressure and issue a warning to the driver have been proposed, such as WO01 / 19626A1 or WO01 / 17806A1. As a device for measuring tire air pressure, a device using a method of indirectly estimating tire pressure by inputting data from an ABS speed sensor or a method of directly measuring tire pressure using a pressure sensor is known. Yes. Moreover, in what was indicated by the said gazette, abnormality of a tire air pressure is detected by monitoring tire temperature, and a driver is warned.
[0004]
However, even if the driver receives a warning about a decrease in tire air pressure, the driver may be traveling on an expressway or may not be able to change tires right away depending on other road conditions. On the other hand, in recent years, run flat tires have been developed that can travel a certain distance even if the tire pressure becomes zero after puncture. Run-flat tires include a core type with a metal or synthetic resin ring core attached to the rim in the tire's air chamber, and a relatively rigid crescent-shaped cross section on the inner surface of the tire sidewall. A side-reinforcing type in which a rubber layer is arranged and reinforced is known. Of these, the core type is used for four or more wheeled vehicles because it has a high load-bearing capacity during run-flat driving, and the side-reinforced type is used for passenger cars or two-wheeled vehicles. Yes.
[0005]
[Problems to be solved by the invention]
Since the run-flat tire can travel to some extent even if it is punctured, it is difficult to notice the puncture. Therefore, a tire pressure alarm device that detects an abnormality in the tire pressure and notifies the driver is essential. However, in the conventional tire pressure alarm device, only a drop in the tire pressure is notified, and the driver cannot know how much he can travel. Therefore, even if a decrease in tire air pressure is informed, a run-flat tire causes the vehicle to continue traveling beyond the specified speed and specified distance, possibly resulting in a serious situation. It was.
[0006]
The present invention has been made in view of the above-described conventional problems, and in a pneumatic tire, particularly a run-flat tire, when a decrease in tire air pressure is detected, how much driving can be performed thereafter is driven. It is an object of the present invention to provide a tire pressure alarm device that allows a driver to take appropriate measures by notifying a driver.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a tire air pressure detecting means for detecting an air pressure in the tire, a tire air pressure detection signal from the tire air pressure detecting means, and the tire air pressure is lower than a predetermined set value. When it is determined that the tire pressure has decreased below the set value, the vehicle travel distance from that time is integrated, and after a preset air pressure decrease A remaining travel distance calculating means for calculating a remaining travel distance that is a difference between the predetermined travel distance of safe travel and the accumulated travel distance, and determining that the travel speed of the vehicle has exceeded a predetermined speed And when the vehicle speed exceeds the predetermined speed, the vehicle speed is less than 1 and the vehicle speed is the predetermined speed. By also back down multiplying factor that retains its value in the remaining travel distance, and the remaining travel distance modifying means for modifying the remaining travel distance depending on the running speed of the vehicle, displays the remaining travel distance Display means, travel distance determination means for determining that the remaining travel distance is less than a predetermined threshold, when it is determined that the remaining travel distance is less than the predetermined threshold, and the travel speed is There is provided a tire air pressure alarm device comprising alarm means for issuing a predetermined alarm when it is determined that a predetermined speed is exceeded .
[0008]
The alarm means is preferably an alarm means for issuing an alarm by at least one of a lamp, a buzzer, and a sound.
[0009]
The tire for detecting the air pressure by the tire air pressure detecting means is a run flat tire, and the predetermined distance that can be safely traveled after the air pressure is lowered is determined by the run flat tire. The predetermined speed set in advance is preferably a speed defined in advance by the run-flat tire .
[0010]
The travel distance is cleared to zero when the air pressure decrease determining means determines that the tire air pressure has decreased below a predetermined set value or when a tire with decreased air pressure is replaced. It is preferable.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a tire pressure alarm device of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings. In the present invention, in a car equipped with a run-flat tire, when the tire pressure falls below a predetermined value, the driver is warned by displaying how much the vehicle can run further according to the situation at that time. Makes it possible to determine what action will be taken thereafter.
[0012]
FIG. 1 is a block diagram showing a schematic configuration of a tire pressure alarm device according to an embodiment of the present invention.
As shown in FIG. 1, the tire pressure alarm device 1 according to the present embodiment mainly includes an air pressure sensor 10 that detects the air pressure in the tire, a control means 12 that receives an air pressure detection signal and other signals and performs various determinations, processes, and the like. According to the judgment result of the control means 12, it has the display means 14 which displays various information, a warning, etc., and the alarm means 16 which issues the warning which notifies that it is a serious situation to a driver | operator.
[0013]
The control means 12 is a core part of the tire air pressure warning device 1 and includes an air pressure drop determination means 18, a remaining travel distance calculation means 20, a travel distance determination means 22, a speed determination means 24, and a remaining travel distance correction means 26. Contains.
The air pressure decrease determining means 18 receives an air pressure detection signal from the air pressure sensor 10 and determines whether or not the tire air pressure falls below a predetermined value set in advance. As a predetermined value serving as a reference for determining this decrease in air pressure, for example, 80% of the normal air pressure of the tire is exemplified. That is, according to this predetermined value, when 20% of the normal air pressure of the tire is released and the air pressure falls, it is determined that the air pressure has been lowered, and an air pressure reduction signal is sent to the remaining travel distance calculation means 20.
[0014]
The vehicle in this embodiment is equipped with run-flat tires, and the air pressure sensor 10 is attached to the rim portion of the wheel. The run flat tire is not particularly limited, and may be a core type or a side reinforcing type. The air pressure sensor 10 is also not particularly limited. For example, the air pressure sensor 10 has a diaphragm made of an elastic material such as silicon rubber at a tire opening that is attached to a wheel rim and communicates with the inside of the tire. The deformation of the diaphragm may be detected as a change in capacitance, or another type. Further, the air pressure sensor 10 is provided with a transmitter (wireless transmission device) that wirelessly transmits a detection signal, and constitutes a sensor tag. The detected tire pressure detection signal is wirelessly transmitted by a wireless transmission device provided in the air pressure sensor 10 constituting the sensor tag. This signal is received by a wireless receiving device provided on the vehicle body side near the tire, and is sent to the air pressure drop determining means 18 of the control means 12.
[0015]
Alternatively, as the tire air pressure detecting means, the tire air pressure of each wheel is calculated based on the wheel speed detected by the wheel speed sensor, for example, in addition to the tire pressure directly measured by the air pressure sensor. It may be asking indirectly. In any case, any device having a function of detecting the air pressure in the tire and sequentially sending the air pressure detection signal to the air pressure drop determining means 18 of the control means 12 may be used.
[0016]
When the remaining travel distance calculation unit 20 receives an air pressure decrease signal indicating that the in-tire air pressure has decreased below the predetermined value from the air pressure decrease determination unit 18, the remaining travel distance calculation unit 20 starts integrating the travel distance of the vehicle from that point. The running distance is accumulated by receiving a signal from a running distance sensor (integrated distance meter) 28 such as a magnet type or an electronic type that detects rotation of an output shaft of a transmission that is usually mounted on the vehicle. The remaining travel distance calculation means 20 integrates the travel distance of the vehicle after the decrease in air pressure is detected, and subtracts this from a predetermined distance (travel limit kilometer) that allows safe travel after the decrease in air pressure. The remaining travel distance is calculated.
[0017]
The predetermined distance for which safe driving can be performed after the air pressure is lowered is, for example, that even if the in-tire air pressure becomes zero, the vehicle can run 80 km at a speed of 80 km per hour by a run-flat tire mounted on the vehicle. The standard determines that the vehicle can travel 100 km at a speed of 60 km per hour.
The remaining travel distance calculating means 20 subtracts the accumulated distance traveled by the vehicle after the decrease in air pressure from the predetermined distance determined by the standard of 80 km or 100 km, and obtains the remaining travel distance (remaining travel distance capable of safe travel). calculate.
[0018]
The remaining travel distance calculated by the remaining travel distance calculation means 20 is displayed on the display means 14. The display means 14 is installed, for example, in an instrument panel near the driver's seat, and displays that the tire air pressure (of at least one of the tires) has decreased, and displays the remaining travel distance that can be safely traveled thereafter. The driver is encouraged to change tires at the nearest tire shop as soon as possible.
[0019]
The remaining travel distance calculated by the remaining travel distance calculation means 20 is also sent to the travel distance determination means 22. The travel distance determination means 22 determines whether or not the remaining travel distance for which safe travel is possible falls below a predetermined threshold value.
The predetermined threshold is appropriately set, for example, a distance of 10% of the limit traveling kilometer. If the remaining travel distance falls below this threshold, it is determined that the travel distance after the decrease in tire air pressure has reached a safe travel distance (travel limit km). A signal is sent to 16 and a warning is displayed on the display means 14 and a warning is issued from the warning means 16.
The alarm means 16 is not particularly limited, and includes an alarm lamp provided near the driver's seat, a buzzer for generating an alarm sound, an audio device for generating an alarm sound from a speaker, or the like. The alarm may be any one of these lamps, buzzers, sounds, etc., or a combination of a plurality of them.
[0020]
As described above, the remaining traveling distance that can be safely traveled is a distance that is guaranteed when traveling at a speed within a prescribed (predetermined) speed, such as 80 km / h, 80 km / h, for example. When the vehicle travels at a speed exceeding the speed, the situation changes and the remaining travel distance is not necessarily guaranteed. In such a case, it is necessary to correct the remaining travel distance.
[0021]
For this purpose, speed determining means 24 and remaining travel distance correcting means 26 are provided. The speed determination means 24 receives a signal from the vehicle speed sensor 30 provided in the normal vehicle, and determines whether or not the traveling speed of the vehicle has exceeded a predetermined speed. This predetermined speed is a speed defined in advance as, for example, 80 km / h by a run-flat tire mounted on the vehicle.
When the speed determination means 24 determines that the vehicle travel speed has exceeded a predetermined (specified) speed, a signal indicating that the vehicle travel speed has exceeded the predetermined speed and the excess speed are sent to the remaining travel distance correction means 26.
[0022]
When the remaining travel distance correction means 26 receives a signal indicating that the predetermined speed has been exceeded from the speed determination means 24, the remaining travel distance correction means 26 receives the accumulated travel distance at that time from the remaining travel distance calculation means 20, and corrects this. .
This correction is performed by applying coefficient processing that multiplies a predetermined coefficient larger than 1 to the accumulated travel distance in accordance with the speed exceeding the predetermined speed detected by the speed determination means 24. That is, when the vehicle travels at a speed greater than a predetermined speed, the remaining travel distance is reduced by correcting the travel distance so that the travel distance exceeds the actual travel distance.
[0023]
As described above, when the vehicle travels at a speed exceeding the predetermined speed, the remaining travel distance correcting means 26 is corrected so as to increase the accumulated travel distance according to the excess for safety. The corrected accumulated travel distance is sent to the travel distance determination means 22, and the travel distance determination means 22 thereafter integrates the travel distance with respect to the corrected accumulated travel distance, and the result is obtained as the predetermined distance. To calculate the remaining travel distance. Therefore, when the vehicle travels over a predetermined speed, the remaining travel distance is reduced according to the excess. The travel distance determination means 22 determines whether or not to issue an alarm by comparing the remaining travel distance corrected in this way with a predetermined threshold value.
[0024]
At this time, even if the remaining travel distance has not yet reached the threshold value, the travel speed is too high, so the alarm means 16 issues an alarm to warn the driver to travel at a reduced speed. You may do it.
In addition, even if the driver reduces the speed by this warning and travels at a speed within a predetermined speed, it is not corrected so as to increase the remaining travel distance , and for the sake of safety, the corrected remaining travel distance is used as it is. An operation is performed.
[0025]
Hereinafter, the operation of the present embodiment will be described with reference to the flowchart of FIG.
First, in step 100, it is assumed that a decrease in tire air pressure is detected. This decrease in air pressure is detected when the air pressure decrease determining means 18 receives an air pressure detection signal from the air pressure sensor 10 and makes a determination at all times during traveling of the vehicle, for example, at regular time intervals. Upon receiving the air pressure detection signal, the air pressure decrease determining means 18 determines whether or not the tire air pressure has decreased in comparison with a predetermined set value. As described above, the set value is, for example, a value that is 20% lower than the normal air pressure. However, the set value is not limited to this value. It is appropriately set depending on the history etc.
[0026]
When a decrease in tire air pressure is detected, in the next step 110, the remaining travel distance calculation means 20 starts to accumulate the travel distance after detecting the decrease in air pressure. When the remaining travel distance calculation means 20 receives the air pressure drop detection signal, it clears the previous travel distance integrated value to 0, receives travel distance data from the travel distance sensor 28, and integrates the travel distance. Clearing of the integrated value may be performed when a tire with reduced air pressure is replaced.
[0027]
In step 120, the remaining travel distance calculation means 20 subtracts the accumulated travel distance after the decrease in air pressure from a predetermined distance (travel limit kilometer) that allows safe travel after the decrease in air pressure, to determine the remaining travel distance. Is calculated.
The calculated remaining travel distance is sent to the travel distance determination means 22 and the display means 14. The display means 14 displays the remaining travel distance to the driver together with a warning message indicating that the tire air pressure has decreased. In this way, not only a warning of a decrease in tire air pressure is issued, but the remaining travel distance is displayed, so that the driver can consider a coping method such as how far the vehicle can travel and where to replace the tire. .
[0028]
In step 130, the speed determination means 24 receives vehicle travel speed data from the vehicle speed sensor 30 at regular time intervals after a decrease in air pressure during vehicle travel is detected, and the travel speed is compared with a predetermined speed set in advance. It is determined whether or not the predetermined speed is exceeded.
If it is determined in this determination that the traveling speed does not exceed the predetermined speed in the travel after the decrease in air pressure, whether or not the remaining travel distance has fallen below a preset threshold in the travel distance determination means 22 in the next step 140. Determined.
[0029]
This threshold value is set in advance to prevent the driver from traveling beyond the travel limit km after the air pressure is reduced. For example, the threshold is 10% of the travel limit km, that is, 10% of the predetermined distance that can be safely traveled after the air pressure is decreased. However, the present invention is not limited to this.
In the travel distance discriminating means 22, the remaining travel distance is compared with the threshold value, and if the remaining travel distance is not yet less than the threshold value, the process returns to step 120, and the accumulated travel distance after the decrease in air pressure The steps of calculating the travel distance, determining the travel speed, and comparing the remaining travel distance with the threshold value are repeated.
[0030]
If it is determined in step 140 that the remaining travel distance is equal to or less than the threshold value, an alarm is issued in step 150. When the travel distance determination unit 22 determines that the remaining travel distance is equal to or less than the threshold value, a signal is sent to the display unit 14 and the alarm unit 16. When the display means 14 receives this signal, the display means 14 displays a message to the driver that the tires have been nearly replaced because the vehicle has nearly reached the driving limit km. Further, the warning means 16 issues a warning to the driver by any one of a lamp, a buzzer, a voice, or a combination thereof.
[0031]
If it is determined in step 130 that the traveling speed exceeds a predetermined speed set in advance, the warning means 16 informs the driver that the speed is too high in step 160. Raise an alarm.
In step 170, when the remaining travel distance correcting means 26 receives a signal from the speed determining means 24 indicating that the travel speed has exceeded a predetermined speed, it receives the accumulated travel distance from the remaining travel distance calculating means 20, On the other hand, the remaining travel distance is corrected by multiplying a predetermined coefficient corresponding to the excess speed.
[0032]
As described above, the run-flat tire is prescribed in advance so that it can run for how many kilometers at a speed of km even when the air pressure becomes zero. Therefore, the run flat tire has a speed exceeding the prescribed speed (predetermined speed). When the vehicle has traveled, the specified travel limit kilometer cannot be guaranteed, so the remaining travel distance is corrected to be in a safer range.
The travel distance discriminating means 22 compares the corrected remaining travel distance with a threshold value in step 140. The subsequent steps are the same as described above.
[0033]
As described above, since the remaining travel (possible) distance after the tire air pressure is decreased is displayed, the driver can appropriately cope with the tire air pressure decrease in consideration of road conditions.
When the driver changes tires at the nearest tire shop or the like, it is preferable that all the remaining travel distance integration routines are automatically reset. The automatic reset function can prevent the driver from forgetting to reset manually and can ensure the correct operation of the system.
[0034]
Also, when the tire punctures while the vehicle is running, the air temperature inside the tire rises rapidly, so not only the air pressure inside the tire but also the air temperature inside the tire, By using it together with the air pressure information, it is possible to more reliably detect a decrease in tire air pressure due to puncture.
Therefore, it is preferable that a temperature sensor is also attached to the air pressure sensor attached to the tire rim, and the temperature detection signal is also wirelessly transmitted to the vehicle body side receiving device by the wireless transmitting device.
[0035]
As described above, the tire pressure alarm device of the present invention has been described in detail. However, the present invention is not limited to the above embodiment, and various improvements and modifications are made without departing from the gist of the present invention. Of course it is also good.
[0036]
【The invention's effect】
As described above, according to the present invention, after the decrease in tire air pressure is detected, the remaining travel distance up to the limit number of kilometers that can be safely traveled is displayed to the driver. On the other hand, the driver can take appropriate measures.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a tire air pressure alarm device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tire pressure alarm apparatus 10 Air pressure sensor 12 Control means 14 Display means 16 Alarm means 18 Air pressure fall determination means 20 Remaining travel distance calculation means 22 Travel distance determination means 24 Speed determination means 26 Remaining travel distance correction means 28 Travel distance sensor 30 Vehicle speed sensor

Claims (4)

Tire pressure detecting means for detecting the tire air pressure;
Receiving a tire air pressure detection signal from the tire air pressure detecting means, and determining that the tire air pressure is lower than a preset value;
When it is determined that the tire internal pressure has decreased below the set value, the travel distance of the vehicle from that time is integrated, and the predetermined distance that can be safely traveled after the air pressure decrease is integrated. A remaining travel distance calculating means for calculating a remaining travel distance that is a difference from the travel distance
Speed determining means for determining that the traveling speed of the vehicle has exceeded a predetermined speed set in advance;
When the speed determining means determines that the traveling speed of the vehicle has exceeded the predetermined speed, a coefficient that is smaller than 1 and maintains the value even when the traveling speed of the vehicle returns to the predetermined speed or less. A remaining travel distance correcting means for correcting the remaining travel distance according to a travel speed of the vehicle by multiplying the remaining travel distance;
Display means for displaying the remaining travel distance;
Travel distance determination means for determining that the remaining travel distance is below a predetermined threshold;
An alarm means for issuing a predetermined alarm when it is determined that the remaining travel distance is below the predetermined threshold, and when it is determined that the travel speed exceeds the predetermined speed ;
A tire pressure alarm device comprising:   2. The tire pressure alarm device according to claim 1, wherein the alarm means is an alarm means for issuing an alarm by at least one of a lamp, a buzzer, and a sound. The tire for detecting the air pressure by the tire air pressure detecting means is a run flat tire,
The predetermined distance that can be safely traveled after the preset air pressure drop is determined by the run-flat tire,
3. The tire pressure alarm device according to claim 1, wherein the predetermined speed set in advance is a speed defined in advance by the run-flat tire . The travel distance is cleared to zero when the air pressure decrease determining means determines that the tire air pressure has decreased below a predetermined set value, or when a tire with decreased air pressure is replaced. The tire pressure alarm device according to any one of 1 to 3 .

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