JP2000142044A - Tire air pressure monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently replace tires without requiring to register identification codes of the respective tires in replacing the tires by registering tire identification codes of a plurality of tire sets in a receiving part for monitoring a tire air pressure of the respective tires and a storage part of this receiving part. SOLUTION: This device has a sensor unit 10 and a monitoring unit 12. A tire air pressure sensor 16 of the sensor unit 10 outputs a signal according to an air pressure to be supplied to a transmitting CPU 18. A transmitting circuit 22 transmits a detecting value and a radio signal containing a tire identification code from a transmitting antenna 24. While, the monitoring unit 12 supplies the received detecting value and the tire identification code to a receiving CPU 36 to be compared with a tire identification code preregistered/prestored in a nonvolatile memory 38 to judge which position tire it is to judge the existence of abnormality of tire air pressure on the basis of the received detecting value to thereby efficiently replace tires.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire pressure monitoring device, and more particularly, to a tire pressure monitoring device which includes a transmitter for transmitting tire pressure information to each tire, and a tire for receiving tire pressure information transmitted from the transmitter. The present invention relates to a tire pressure monitoring device including:

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open Publication No.
As disclosed in No. 9, a remote tire pressure monitoring system is known. This remote tire pressure monitoring system is mounted on each tire, detects tire pressure, encodes this detected value, and transmits it together with an identification code of the tire position, and a transmitter provided on the vehicle body and transmitted from each transmitter. And a receiver for receiving and analyzing the signal and supplying the analyzed signal to the driver information console. It discloses that when a tire is replaced, the identification codes of the transmitters of all the tires are stored in the receiver, and the new tire position is notified to the system.

[0003]

In a tire pressure monitoring device such as the above-mentioned conventional remote tire pressure monitoring system, when a standard tire and a studless tire are replaced each time the season changes, each time the replacement is carried out, It is necessary to store the identification code of the transmitter of all tires in the receiver and teach the new tire position to the system,
There was a problem of inefficiency.

[0004] The present invention has been made in view of the above points, and by registering tire identification codes of a plurality of tire sets in a storage unit of a receiving unit, each tire can be regularly replaced when tire replacement is performed. It is an object of the present invention to provide a tire pressure monitoring device which does not need to register the identification code of the tire.

[0005]

According to a first aspect of the present invention, there is provided a transmitter for detecting a tire pressure and transmitting the detected value together with a tire identification code, and receiving the detected value and the tire identification code to receive the detected value and the tire identification code. A tire pressure monitoring device comprising: a reception unit that specifies a tire by comparing the tire identification code with a tire identification code registered in a storage unit and monitors a tire pressure of each tire; To
A tire identification code of a plurality of tire sets is registered.

As described above, since the tire identification codes of a plurality of tire sets are registered in the storage unit of the receiving unit, for example, the standard tire and the studless tire are changed every time the season changes, that is, periodically changed. In this case, there is no need to register the identification code of each tire, and tire replacement can be performed efficiently. According to a second aspect of the present invention, in the tire pressure monitoring device according to the first aspect, the registration of the tire identification code in the storage unit of the receiving unit includes the steps of:
Air injection into the tire is triggered.

As described above, the registration of the tire identification code in the storage unit of the receiving unit is performed by injecting air into the tire as a trigger. Therefore, when registering the tire identification code, a special device such as a magnet is required. And not. According to a third aspect of the present invention, in the tire pressure monitoring device according to the first aspect, the registration of the tire identification code in the storage unit of the receiving unit is performed by reading the tire identification code attached to the tire by code reading means. The signal is supplied from the code reading unit to the receiving unit through a connection cable.

As described above, the registration of the tire identification code in the storage unit of the receiving unit is performed by reading the tire identification code attached to the tire by the code reading unit and supplying the tire identification code to the receiving unit through the connection cable. Even if the tire identification code of one vehicle is registered at the same time, it is possible to prevent the tire identification code of another vehicle from being erroneously registered.

[0009]

FIG. 1 is a system configuration diagram of a tire pressure monitoring device according to an embodiment of the present invention. In this embodiment, the tire pressure is a predetermined set pressure Pse.
It is adjusted to be t. The tire pressure monitoring device of the present embodiment is a device that monitors the tire pressure and issues an alarm indicating an abnormality of the tire pressure when the tire pressure drops below a predetermined value from a set pressure Pset.

As shown in FIG. 1, the tire pressure monitoring device of this embodiment includes a sensor unit 10 and a monitoring unit 12. The sensor unit 10 is mounted inside the wheel, and is driven using the built-in battery 14 as a power supply. As shown in FIG.
Has a tire pressure sensor 16, a transmission CPU 18, a non-volatile memory 20, and a transmission circuit 22.

The tire pressure sensor 16 is a pressure sensor that outputs a signal corresponding to the tire pressure. The output signal of the tire pressure sensor 16 is supplied to the transmission CPU 18. The transmission CPU 18 detects the tire pressure based on the output signal of the tire pressure sensor 16 and compares the detected value (hereinafter referred to as a detected value Pm) with reference values Pa and Pb stored in the nonvolatile memory 20. The detection value Pm is supplied to the transmission circuit 22 at a frequency corresponding to the detection value Pm. Further, a tire identification code is stored in the non-volatile memory 20, and this tire identification code is supplied to the transmission circuit 22 together with the detection value Pm. The transmission circuit 22 detects the detection value Pm
And a radio signal including a tire identification code
To the monitoring unit 12.

On the other hand, the monitoring unit 12 is installed in the cabin, and is driven by using the battery of the vehicle as a power supply. As shown in FIG. 1, the monitoring unit 12 includes a transmission / reception circuit 34, a reception CPU 36, a nonvolatile memory 38, and a tire set selection switch (SW) 39. The receiving circuit 34 is connected to the sensor unit 10 via the receiving antenna 32.
The radio signal transmitted from the side is received, and the detection value Pm and the tire identification code included in this signal are supplied to the reception CPU 36. The receiving CPU 36 compares the received tire identification code with the tire identification code previously registered and stored in the non-volatile memory 38 to determine which tire (front left wheel, front right wheel, left rear wheel, right rear wheel) Is determined, and the presence or absence of an abnormality in the tire pressure is determined based on the received detection value Pm.

Here, the nonvolatile memory 38 stores tire identification codes of a plurality of tire sets (for example, two sets). For example, as shown in FIG. 2, tire identification codes IDA1 to IDA5 of standard tires are registered in addresses # 0 to # 4 of the nonvolatile memory 38. I
DA1 is a left front wheel tire identification code, IDA2 is a right front wheel tire identification code, IDA3 is a left rear wheel tire identification code,
IDA4 is a tire identification code of the right rear wheel, and IDA5 is a tire identification code of the spare tire. Also, address # 5
# 9 is a tire identification code IDB1 of a studless tire.
To IDB5 are stored. IDB1 is the tire identification code of the left front wheel, IDB2 is the tire identification code of the right front wheel, IDB3
Is the tire identification code of the left rear wheel, IDB4 is the tire identification code of the right rear wheel, and IDB5 is the tire identification code of the spare tire. The tire set selection switch 39 instructs which tire set registered in the nonvolatile memory 38 to use the tire identification code.

If a predetermined value (for example, all zeros) is registered in addresses # 4 and # 9 where the tire identification code of the spare tire is registered, it indicates that the spare tire of the tire set is not mounted. It is conceivable that a studless tire used only for a short period of time may not be equipped with a spare tire. In this case, all zeros are registered in address # 9. This is because the tire identification code IDB5 of the spare tire is registered at the address # 9, and when the spare tire of the studless tire is not actually mounted, the receiving CPU 36 transmits the wireless signal from the spare tire of the studless tire for a predetermined time or more. If no signal is transmitted, it is erroneously determined that the spare tire of the studless tire is abnormal (battery exhausted).

As described above, since the tire identification codes of a plurality of tire sets are registered in the non-volatile memory 38 of the monitoring unit 12, for example, the standard tire and the studless tire are changed every season, that is, periodically. In the case of replacement, there is no need to register the identification code of each tire, and tire replacement can be performed efficiently.

The monitoring unit 12 also has a display warning device 40. The display / warning device 40 displays a numerical value of the tire pressure, and gives a warning when the tire pressure is abnormal by, for example, first to third warning lights. The receiving CPU 36 stores predetermined first to third alarm values P1, P2 in the nonvolatile memory 38.
2 and P3 (P1>P2> P3), and when the detection value Pm falls below P1, P2, and P3, the first warning light, the second warning light, and the second warning light of the display warning device 40 are sequentially displayed. 3 Turn on the warning light.

The first to third alarm values P1 to P3 are set to 1.5 atm, 0.7 atm, and 0 atm, respectively, based on the atmospheric pressure. Therefore, the first
A warning (first warning) indicating an initial decrease in tire pressure is provided by turning on the warning light, a warning (second warning) indicating tire puncture is provided by turning on the second warning light, and a third warning light is turned on. As a result, an alarm (third alarm) indicating that the air in the tire has completely escaped is issued.

Note that the number of alarm values is not limited to three, and one, two, or four or more alarm values may be provided. Further, instead of the first to third warning lights, for example, an alarm device that issues an alarm by sound such as a buzzer may be provided. To register the tire identification code in the nonvolatile memory 38, a registration switch provided in advance is operated to enter the registration mode. After the registration mode is entered, for example, the left front wheel, the right front wheel, the left rear wheel, The tire identification code is registered in the order of the right rear wheel and the spare tire (the order is determined in advance). Of course, the registration switch may be used to specify the left front wheel, the right front wheel, the left rear wheel, the right rear wheel, and the spare tire for registration. Further, the registration may be performed in any order unless it is necessary to distinguish the front left wheel, the front right wheel, the rear left wheel, the rear right wheel, and the spare tire.

By the way, tire replacement (rotation)
Is performed, it is necessary to re-register the tire identification code registered in the nonvolatile memory 38. Conventionally, a strong magnet or the like is brought close to the tire and swept to make the sensor unit 10
Is set as the registration mode, and the tire identification code is transmitted. The monitoring unit receives the tire identification code for registration. In this case, a special device such as a strong magnet is required. In the present invention, the tire identification code is re-registered in the non-volatile memory 38 at the time of inflation, so that a special device is not required when re-registering.

FIG. 3 shows a flowchart of a routine executed by the transmission CPU 18 of the present invention. This routine is repeatedly executed at predetermined time intervals. When the routine shown in FIG. 3 is started, first, step S10 is executed. In step S10, the current tire pressure Pm is detected based on the output signal of the tire pressure sensor 16. In step S11 following step S10, the difference dP (= Pm−) between the current tire pressure Pm and the previous tire pressure Pmk.
Pmk) exceeds a predetermined value dP1.
When dP ≦ dP1, the process proceeds to step S12, where dP> d
In the case of P1, the process proceeds to step S24.

In step S12, it is determined whether or not the tire pressure Pm is lower than a predetermined reference value Pa (for example, Pa = P1). As a result, if an abnormality has occurred in the tire pressure when Pm <Pa, then step S14 is executed. In step S14, the timer T reaches a predetermined value t.
It is determined whether it is 1 or more, and if T ≧ t1, step S1
Proceeding to 6, the tire pressure Pm and the tire identification code are transmitted to the monitoring unit 12. The predetermined value t1 is, for example, 2
This is a value corresponding to ~ 3 seconds. Thereafter, the timer T is reset to 0 in step S18, 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 flow advances to step S22. In step S22, the tire pressure Pm detected this time is transferred to the previous tire pressure Pmk, and this processing cycle ends. D in step S11
In the case of P> dP1, it is determined that the tire pressure has been rapidly increased, that is, the air has been injected into the tire, and the process proceeds to step S24 with this as a trigger, and the tire identification code is re-registered in the nonvolatile memory 38. For this purpose, the tire identification code read from the nonvolatile memory 20 is transmitted to the monitoring unit 12 continuously N times (several times to several tens times). Thereafter, this processing cycle is ended. The reason why the tire identification code is repeatedly transmitted N times is to prevent the monitoring unit 12 from missing reception.

As described above, since the registration of the tire identification code in the non-volatile memory 38 is performed by injecting air into the tire as a trigger, a special device such as a magnet is required when registering the tire identification code. do not do. FIG. 4A shows a frame format of a signal for transmitting the tire pressure Pm and the tire identification code in step S16. In the figure, a start bit for synchronization is provided at the head, and a tire identification code for identifying the sensor unit 10 is provided next. Next, the cord of the tire pressure Pm is arranged.
Finally, a stop bit for synchronization is provided. On the other hand, FIG. 4B shows a frame format of a signal transmitted to re-register the tire identification code in step S24. In the figure, a start bit for synchronization is provided at the head, and a tire identification code for identifying the sensor unit 10 is repeatedly arranged twice, and the tire pressure Pm is not arranged. Finally, a stop bit for synchronization is provided.

As described above, by making the signal frame format for transmitting the tire pressure Pm different from the signal frame format for transmitting the tire identification code, the tire identification code is re-registered. Even if a signal of the signal frame format of FIG. 4A is transmitted from a sensor unit provided on a tire of a nearby vehicle, the tire identification code of the signal frame format of FIG. It will not be done.

A receiving antenna is provided in the vicinity of a base for injecting air into the tire of the air injecting apparatus, and this receiving antenna is connected to the receiving antenna 32 of the monitoring unit 12 to increase the receiving sensitivity. Alternatively, when the monitoring unit 12 receives a signal of the signal frame format shown in FIG. 4B, the display and warning device 40 may display the received tire identification code.

When the vehicle is manufactured, it is necessary to register the tire identification code in the nonvolatile memory 38. Conventionally, a strong magnet or the like is brought close to the tire and swept to make the sensor unit 1
0 is set as the registration mode, the tire identification code is transmitted, and the tire identification code is received and registered by the monitoring unit. In this case, the tire identification code is simultaneously stored in the nonvolatile memory 38 of a plurality of vehicles at the manufacturing factory. When trying to register, the signal transmitted from the sensor unit 10 of the adjacent vehicle is received by the monitoring unit of the own vehicle, and there is a risk of erroneous registration.

In the present invention, when registering a tire identification code in the nonvolatile memory 38, the tire identification code is input from a bar code and registered, whereby the tire identification code is stored in the nonvolatile memory 38 of a plurality of vehicles at a manufacturing factory. Can be registered at the same time. For this reason, in the sensor unit manufacturing process, the nonvolatile memory 20 of each sensor unit 10 is used.
Is recorded on a sticker (or tag) with a bar code, and the bar code recording sticker is stored in a pair with the sensor unit 10 or its packaging.

Next, in the tire assembling process, the sensor unit 10 is installed in the tire and assembled to the wheel, and the sensor unit 10 and a pair of barcode recording stickers are attached to the assembled tire. Furthermore, in the vehicle assembly process,
After assembling the tire and the monitoring unit 12 into the vehicle, the bar code of the bar code recording sticker 52 attached to the tire 50 is read by a bar code reader 54 as shown in FIG.
, And reads the read tire identification code from the bar code reader 54 through the connection cable 56 to the monitoring unit 1.
Feed to 2. In this case, the monitoring unit 12 receives the tire identification code from the barcode reader 54, and
An input interface 58 is provided to supply to U36.

As described above, at the time of registration, the tire identification code is read by the bar code reader 54 and the connection cable 56 is read.
Even if the tire identification codes of a plurality of vehicles are registered simultaneously at a short distance, the tire identification codes of the sensor units 10 of the adjacent vehicles are erroneously registered in the nonvolatile memory 38 of the own vehicle. There is no danger.

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 the bar code reader 54 reads the code. Corresponding to the means.

[0031]

As described above, the first aspect of the present invention provides
Since the tire identification codes of a plurality of tire sets are registered in the storage unit of the receiving unit, for example, each time the season changes between the standard tire and the studless tire, that is, when the tire is periodically replaced, the identification of each tire is performed. There is no need to register a code, and tire replacement can be performed efficiently.

According to the second aspect of the present invention, the registration of the tire identification code in the storage unit of the receiving unit is performed by injecting air into the tire as a trigger. No special equipment is required. According to the third aspect of the present invention, the registration of the tire identification code in the storage unit of the receiving unit is performed by reading the tire identification code attached to the tire by code reading means and supplying the tire identification code to the receiving unit through the connection cable. Even if the tire identification codes of a plurality of vehicles are registered at the same time, it is possible to prevent erroneous registration of the tire identification codes of other vehicles.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a tire pressure monitoring device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the relationship between addresses and stored contents of a nonvolatile memory 38 according to the present invention.

FIG. 3 is a flowchart of a routine executed by a transmission CPU 18 of the present invention.

FIG. 4 is a diagram showing a signal frame format of the present invention.

FIG. 5 is a diagram illustrating registration of a tire identification code according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 sensor unit 12 monitoring unit 14 built-in battery 16 tire pressure sensor 18 transmission CPU 20, 38 non-volatile memory 22 transmission circuit 28 reception circuit 34 reception circuit 36 reception CPU 39 tire set selection switch 52 barcode recording seal 54 barcode reader 56 connection Cable 58 input interface

Claims (3)

[Claims] A transmission unit for detecting a tire air pressure and transmitting the detected value together with a tire identification code; and a tire identification unit which receives the detected value and the tire identification code and registers the tire identification code in a storage unit. A tire pressure monitoring device comprising: a receiving unit that identifies a tire by comparing with a code and monitors a tire pressure of each tire, wherein a tire identification code of a plurality of tire sets is registered in a storage unit of the receiving unit. A tire pressure monitoring device, characterized in that: 2. The tire pressure monitoring device according to claim 1, wherein the registration of the tire identification code in the storage unit of the receiving unit is performed by injecting air into the tire as a trigger. 3. The tire pressure monitoring device according to claim 1, wherein the registration of the tire identification code in the storage unit of the receiving unit is performed by reading the tire identification code attached to the tire by code reading unit, and the code reading unit. A tire pressure monitoring device, wherein the tire pressure is supplied to the receiving unit through a connection cable.