JP3428466B2 - Tire pressure warning device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire air pressure alarm device, and more particularly to a tire air pressure alarm device suitable for extending the life of a battery that drives a transmitter.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open Publication No. 8-50773.
Tire condition monitoring systems are known, as disclosed in US Pat. This tire condition monitoring system has a sensor attached to the tire for detecting the temperature and the tire pressure of the tire, a unit for encoding and transmitting the detected value at a predetermined time interval, and a unit provided on the vehicle body side for transmitting the signal. And an analysis unit for receiving and analyzing the signal.
When the tire air pressure is decreased or the temperature is increased, the unit transmits the detection value at a shorter time interval than the predetermined time interval in the normal condition.

[0003]

In the conventional tire condition monitoring system described above, when the tire air pressure decreases, the unit transmits the detection value at a short time interval, and this is continued for a period when the tire air pressure is low. There is a problem that the life of the battery that supplies power to the unit is shortened when the battery voltage drops.

The present invention has been made in view of the above points, and when the driver determines that the warning is recognized, the transmission time interval of the detected value is made longer than the transmission time interval at the time of abnormality. Thus, it is an object of the present invention to provide a tire pressure warning device capable of suppressing the power consumption of the transmitting unit when the tire pressure is abnormal.

[0005]

According to a first aspect of the present invention, a driver detects a tire air pressure and transmits the detected value, and a driver when receiving the detected value and the tire air pressure drops. A tire pressure warning device having a receiving section that gives a warning to the transmitting section, wherein the transmission of the detected value by the transmitting section is performed at different predetermined time intervals during normal time and abnormal time, and is connected to the receiving section. Reset switch
When it is determined that the driver has recognized the warning when turned on, there is a transmission time interval extending means for making the transmission time interval of the detected value longer than the transmission time interval at the time of the abnormality.

Thus, the reset connected to the receiving section
When it is determined that the driver has recognized the warning by turning on the switch, the transmission time interval of the detected value can be made longer than the transmission time interval of the abnormal condition to suppress the power consumption of the transmitter in the abnormal condition . It is possible to extend the life of the. The invention according to claim 2 detects the tire pressure.
And a transmitter that transmits the detected value and receives the detected value.
To warn the driver in the event of a tire pressure drop.
A tire pressure warning device having a
The transmission of the detected value by the transmission unit is performed during normal time and abnormal time.
At different predetermined time intervals and the ignition
The driver recognizes the warning by turning the switch off.
If it is determined that the transmission time interval of the detected value is
Extend the transmission time interval to make it longer than the transmission time interval at the time of abnormality
Have means .

If the driver recognizes the warning that the tire pressure has dropped, the vehicle should be stopped and the ignition switch turned off. Therefore, no special switch is provided.
It is possible to judge that the driver has recognized the warning and
When the driver judges that the notification has been recognized, the detection value is sent.
To make the time interval longer than the transmission time interval at the time of abnormality
The power consumption of the transmitter in the event of an abnormality can be reduced and
It is possible to extend the life of the pond and that Do not.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system configuration diagram of a tire pressure warning device according to an embodiment of the present invention. In this embodiment, the tire air pressure is a predetermined set air pressure Pset.
Has been adjusted to be The tire air pressure alarm device according to the present embodiment is a device that monitors tire air pressure and issues an alarm indicating an abnormal tire air pressure when the tire air pressure falls below a set value from the set air pressure Pset.

As shown in FIG. 1, the tire pressure warning device of this embodiment includes a sensor unit 10 and a monitoring unit 1.
Equipped with 2. The sensor unit 10 is mounted inside the wheel, and is driven by the built-in battery 14 as a power source. As shown in FIG. 1, the sensor unit 10
Includes a tire pressure sensor 16, a transmission CPU 18, a non-volatile memory 20, a transmission circuit 22, and a reception circuit 28.

The transmission data from the transmission circuit 22 includes an identification signal of the sensor unit 10, and the monitoring unit 12 is the one in which the reception data is transmitted from the sensor unit 10 mounted on the vehicle by this identification signal. Have identified. For this reason, it is necessary to store the identification signal of the sensor unit 10 mounted in the own vehicle in the monitoring unit 12, and this storage work is performed when the vehicle is assembled. At this time, the storage operation may be performed after waiting for the data transmission from the sensor unit 10, but the data transmission from the sensor unit 10 is every 10 to 20 minutes as described later.
The monitoring unit 1
A signal indicating that the storage operation is being performed is transmitted from 2 to the sensor unit 10, and the data transmission from the sensor unit 10 is forcibly performed to shorten the storage operation.

The tire air pressure sensor 16 is an air pressure sensor that outputs a signal corresponding to the tire air pressure. The output signal of the tire pressure sensor 16 is supplied to the transmission CPU 18. The transmission CPU 18 detects the tire air pressure based on the output signal of the tire air pressure sensor 16 and compares the detected value (hereinafter referred to as the detected value Pm) with the reference values Pa and Pb stored in the non-volatile memory 20, The detection value Pm is supplied to the transmission circuit 22 at a frequency according to the detection value Pm.

The transmission circuit 22 transmits a radio signal including the detected value Pm from the transmission antenna 22 to the monitoring unit 12. Further, the consultation circuit 28 receives the wireless signal transmitted from the monitoring unit 12 via the reception antenna 26 and transmits the reset signal included in this signal to the CPU 18
Supply to. On the other hand, the monitoring unit 12 is installed in the vehicle compartment and is driven by the battery of the vehicle as a power source. As shown in FIG. 1, the monitoring unit 12 includes a transmission / reception circuit 34 and a reception CPU 36. Transmitter / receiver circuit 3
4 receives the wireless signal transmitted from the sensor unit 10 side via the antenna 32, and supplies the detection value Pm contained in this signal to the reception CPU 36. Receiving CPU 36
Determines whether there is an abnormality in tire air pressure based on the detected value Pm.

The monitoring unit 12 also includes a display warning device 38. The display / warning device 38 displays a numerical value of the tire air pressure, and gives a warning when the tire air pressure is abnormal, for example, by using first to third warning lights. The reception CPU 36 has a built-in non-volatile memory in which predetermined first to third alarm values P1,
P2 and P3 (P1>P2> P3) are stored,
When the detected value Pm falls below P1, P2, and P3,
The first warning light, the second warning light, and the third warning light of the display warning device 38
Turn on the warning light.

The first to third alarm values P1 to P3 are set to, for example, 1.5 atm, 0.7 atm, and 0 atm based on the atmospheric pressure. Therefore, the first
An alarm (first alarm) that indicates an initial decrease in tire pressure when the warning light is lit, an alarm that indicates puncture of the tire (second alarm) when the second warning light is lit, and a third warning light is lit. As a result, an alarm (third alarm) indicating that the tire air is completely exhausted is issued.

The number of alarm values is not limited to three, and one or two alarm values or four or more alarm values may be provided. Further, instead of the first to third warning lights, for example, an alarm device for issuing an alarm by sound such as a buzzer may be provided. In addition, the receiving CPU 36 of the monitoring unit 12
A reset switch 40 is connected to the. The reset switch 40 is a switch that is turned on by the operation of the driver when the driver recognizes an abnormality in the tire pressure by the display warning device 38. When the reset switch 40 is turned on, the reception CPU 36 supplies a reset signal to the transmission / reception circuit 34, and the transmission / reception circuit 34 transmits a wireless signal including the reset signal from the antenna 32 to the sensor unit 10.

By the way, as described above, the sensor unit 1
0 is driven by the built-in battery 14 as a power source because it is provided inside the wheel. The sensor unit 10 is
In particular, the transmitting circuit 22 consumes a large amount of power when transmitting a wireless signal. Therefore, in order to extend the life of the built-in battery 14, the detection value Pm is transmitted intermittently, and
It is desirable to increase the transmission time interval.

On the other hand, when the tire air pressure drops below a predetermined value, it is necessary to have the driver take appropriate measures according to this situation, and therefore it is necessary to shorten the transmission time interval of the detected value Pm. However, after the driver recognizes that the tire pressure has dropped below a predetermined value, the detected value Pm
Is less necessary even if the transmission time interval is shortened, and only the problem that the transmission time interval of the detection value Pm is short and the power consumption of the built-in battery 14 is large remains. Therefore, in the present embodiment, after the driver recognizes the tire pressure abnormality, the transmission time interval of the detection value Pm is lengthened to suppress the power consumption of the built-in battery 14.

FIG. 2 shows a flow chart of a routine executed by the transmission CPU 18 of the present invention. When the routine shown in FIG. 2 is started, first, step S10 is executed.
In step S10, the current tire air pressure Pm is detected based on the output signal of the tire air pressure sensor 16. In step S12 subsequent to step S10, the reset flag is off, and the tire air pressure Pm is the predetermined reference value Pa.
(For example, Pa = P1) is determined.

As a result, the reset flag is off, and
If Pm <Pa and the tire pressure is abnormal, then step S14 is executed. Step S14
Then, it is determined whether or not the timer T is equal to or more than the predetermined value t1, and T ≧
In the case of t1, the process proceeds to step S16 and the tire air pressure Pm
To the monitoring unit 12. The above-mentioned predetermined value t1 is a value corresponding to, for example, 2 to 3 seconds. After this, step S
At 18, the timer T is reset to 0 and the process proceeds to step S22.

On the other hand, if T <t1 in step S14, the timer T is incremented by 1 in step S20 and the process proceeds to step S22. In step S22, it is determined whether or not a wireless signal including a reset signal is received from the monitoring unit 12, and if the reset signal is not received, the current tire air pressure Pm is determined based on the output signal of the tire air pressure sensor 16 in step S23. After detection, step S
Proceed to 14. If a reset signal is received, the reset flag is turned on in step S24 and then step S30.
Proceed to.

By the way, if the reset flag is turned on in step S12 or the tire pressure is normal with Pm ≧ Pa, the process proceeds to step S30. In step S30, it is determined whether or not the timer T is equal to or greater than the predetermined value t2. If T ≧ t2, the process proceeds to step S32 to transmit the tire air pressure Pm to the monitoring unit 12. The predetermined value t2 is, for example, 10
It is a value corresponding to 20 minutes. After this, step S34
Then, the timer T is reset to 0 and the process proceeds to step S10.
On the other hand, if T <t2 in step S30, step S3
At step S1, the timer T is incremented by 1 at step S1.
Go to 0.

That is, if Pm ≧ Pa and the tire pressure is normal, steps S10, S12, and S30 to S36 are repeated. Therefore, the detection value Pm is transmitted to the monitoring unit 12 at a long transmission time interval of about 10 to 20 minutes. The power consumption of the built-in battery 14 is suppressed. When Pm <Pa and the tire pressure becomes abnormal, steps S14 to S23 are repeated and the detection value Pm is transmitted to the monitoring unit 12 at a short transmission time interval of 2 to 3 seconds.

When the driver recognizes an abnormality in the tire pressure and turns on the reset switch 40, the process proceeds from step S22 to step S24 to turn on the reset flag and set 10 to 20.
The detection value Pm is transmitted to the monitoring unit 12 at a long transmission time interval of about a minute to suppress the power consumption of the internal battery 14.
As a result, the life of the built-in battery 14 can be extended.

By the way, if the driver recognizes the warning that the tire pressure has dropped, the vehicle should be stopped and the ignition switch turned off to check the tire. Therefore, when the ignition switch is turned off, the reset flag is turned on. Then, it is possible to determine that the driver has recognized the warning without providing the reset switch 40. If the ignition switch is turned off,
The normal transmission time interval may be set longer than when the ignition switch is turned on.

In the above embodiment, the transmission time interval when the reset flag is on is set to 10 to 20 which is the same as the normal time.
Although it is set to about minutes, the transmission time interval when the reset flag is on is the transmission time interval 2 when the reset flag is off.
If it is longer than ~ 3 seconds, even shorter than 10 ~ 20 minutes,
Alternatively, it may be long, and further transmission of the detected value Pm thereafter may be stopped.

In the above embodiment, the sensor unit 10 corresponds to the transmitting section described in the claims, the monitoring unit 12 corresponds to the receiving section described in the claims, and steps S12, S22, and S24 are performed. Corresponds to the transmission time interval extension means.

[0027]

As described above, according to the invention, the invention described in claim 1
If the reset switch connected to the receiver is turned on,
If the driver recognizes that the warning
Make the transmission time interval longer than the transmission time interval at the time of abnormality.
This helps reduce the power consumption of the transmitter in the event of an abnormality.
Battery life can be extended.

Further , according to the invention described in claim 2,
Stop the vehicle if the driver recognizes a low air pressure warning
I should turn off the ignition switch.
Therefore, the driver can give a warning without installing a special switch.
You can judge that you recognized it, and the driver acknowledges the warning.
If it is judged that it has been recognized, the transmission time interval of the detected value is abnormal
By setting longer than the transmission time interval of
The power consumption of the transmitter can be reduced and the battery life can be extended.
Can be done.

[0029]

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a tire pressure warning device that is an embodiment of the present invention.

FIG. 2 is a flowchart of a routine executed by the transmission CPU 18 of the present invention.

[Explanation of symbols]

10 sensor unit 12 Monitoring unit 14 Built-in battery 16 Tire pressure sensor 18 Send CPU 20 Non-volatile memory 22 Transmitter circuit 28 Receiver circuit 34 Transmitter / receiver circuit 36 Receiving CPU 38 Display warning device 40 reset switch

Claims (2)

(57) [Claims] 1. A tire pressure warning device comprising: a transmitter for detecting a tire pressure and transmitting the detected value; and a receiver for receiving the detected value and alerting a driver when the tire pressure is low. The transmission of the detected value by the transmitting unit is performed at a predetermined time interval that differs between a normal time and an abnormal time, and the receiving unit
A transmission time interval extending means for making the transmission time interval of the detected value longer than the transmission time interval of the abnormality when it is determined that the driver recognizes the warning by turning on the reset switch connected to Tire pressure warning device characterized by. 2. A tire pressure is detected and the detected value is sent.
A transmission unit signal for, at the time of abnormality of tire air pressure is lowered to receive the detection value
Tire pressure alarm with receiver for warning driver
In the device, the transmission of the detection value by the transmission unit is performed during normal time and abnormal time.
And the ignition are performed at different time intervals.
The driver recognizes the warning by turning the switch off.
If it is determined that the detection value transmission time interval
Note: The transmission time interval extension is set to be longer than the transmission time interval when an error occurs.
A tire pressure warning device characterized by having a long means .