JP2003002020A - Detecting system of tire air pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detecting system of tire air pressure that is inexpensive and easily assembled, in relation to the detecting system for detecting air pressure of each tire of a vehicle and informing a driver of it. SOLUTION: This detecting system of tire air pressure is constituted so that a tire air pressure signal from a transmitting device 10 mounted to each tire of the vehicle is received by a plurality of receiving devices 31 that are disposed near the transmitting device and have a built-in receiving antenna and a control device 4 determines whether or not a tire air pressure value is in a normal range based on the signal. Thus, the detecting system requires no expensive coaxial cable, has a low material cost, and allows easy wiring work.

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 detection system for detecting the air pressure of each tire of a vehicle and notifying the tire pressure to a driver or the like.

[0002]

2. Description of the Related Art In recent years, a tire pressure detection system in which a transmitter is mounted on each tire of a vehicle and which uses radio waves to notify the tire pressure state of the vehicle is increasing.

Such a conventional tire air pressure detection system will be described with reference to FIG.

FIG. 8 is a block diagram of a conventional tire air pressure detection system. In FIG. 8, reference numeral 1 denotes a transmitter mounted on each tire of a vehicle for detecting a tire air pressure value and transmitting this as a tire air pressure signal. is there. Reference numeral 2 is a receiving antenna installed near the tire, and 3 is a receiving device for receiving and outputting a signal output from the receiving antenna 2.

Reference numeral 4 converts a tire pressure signal output from the receiving device 3 into a tire pressure value and compares it with a tire pressure minimum value or a tire pressure maximum value for each tire stored in advance so that the tire pressure is normal. The control device 5 for determining whether or not the range is a display device such as a liquid crystal display for displaying the content determined by the control device 4.

In the case of a vehicle, various noises such as engine noise are generated. Therefore, the receiving antenna 2 and the receiving device 3 installed near each tire are connected by a noise-resistant coaxial cable 6. Is configured to.

In the above structure, the transmitter 1 mounted in each tire detects a tire air pressure value with a sensor or the like, converts the tire air pressure value into a tire air pressure signal, modulates the tire air pressure signal, and transmits the high frequency signal.

The high frequency signal from the transmitter 1 is received by the receiving antenna 2 installed near the tire, and the received high frequency signal is output to the receiver 3 through the coaxial cable 6 resistant to noise.

Then, the receiving device 3 demodulates the high frequency signal output from the receiving antenna 2, converts it into a tire air pressure signal, and outputs the obtained tire air pressure signal to the control device 4.

The control device 4 converts the tire air pressure signal output from the receiving device 3 into a tire air pressure value, and compares the tire air pressure value with the tire air pressure minimum value or tire air pressure maximum value of each tire which is stored in advance. It is determined whether it is within the normal range, and if the determined content is not within the normal range, the display device 5 displays such as "tire pressure abnormality" and notifies the driver that the tire pressure is abnormal. To do.

[0011]

However, in the above-mentioned conventional tire pressure detection system, since the plurality of receiving antennas 2 are connected to the receiving device 3 by the expensive coaxial cable 6, the material cost becomes high, and There is also a problem that it takes time for wiring when assembling the vehicle.

SUMMARY OF THE INVENTION The present invention is intended to solve such a conventional problem, and an object thereof is to provide a tire pressure detection system which is inexpensive and easy to assemble.

[0013]

In order to achieve the above object, the present invention has the following constitution.

According to the first aspect of the present invention, a tire pressure signal from a transmitter mounted on each tire of a vehicle is received by a plurality of receivers disposed near the transmitter and having a built-in receiving antenna. The tire pressure detection system is configured so that the control device determines whether the tire pressure value is within the normal range from this signal, and a signal from the transmitter is transmitted by a plurality of receivers having a receiving antenna. Since the signal is received, the transmission distance of the high frequency signal output from the antenna is short, and the effect of ambient noise can be reduced, so expensive coaxial cables are not required, material costs are low, and wiring work is easy. It has the effect of realizing the system.

According to a second aspect of the invention, in the first aspect of the invention, the transmitter transmits the identification number of each transmitter, and the transmitter transmits the identification number of each transmitter in addition to the tire pressure signal. Since it also transmits, even when the receiving device other than the signal placed in the vicinity is received, the control device can determine which transmitting device the tire pressure signal is from,
It has an effect that the air pressure of each tire can be reliably detected.

According to a third aspect of the present invention, in the second aspect of the present invention, the signal output from the receiving device is added to the receiving level indicating the strength at the time of reception and output to the control device, or
Only a signal of a predetermined reception level or higher is output to the control device, and the control device determines the tire pressure signal only when the input reception level is equal to or higher than the reference reception level registered in advance, or By making sure that only signals with a predetermined reception level or higher are input, the control device can make a decision only with a good tire pressure signal having a predetermined strength, thus realizing a tire pressure detection system with few erroneous determinations. It has the effect of being able to.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the plurality of receiving devices output a receiving level indicating the strength of reception, and the control device outputs a tire pressure signal having a large receiving level. The tire air pressure value is determined by using the tire air pressure value. Since the control device determines the tire air pressure signal having the highest reception level among a plurality of signals, it has the effect of making a more reliable determination.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

The same components as those described in the section of the prior art are designated by the same reference numerals to simplify the detailed description.

(First Embodiment) Using the first embodiment,
The invention of claims 1 and 2 will be described.

FIG. 1 is a block diagram of a tire air pressure detection system according to a first embodiment of the present invention. In FIG. 1, 10 is mounted on each tire of a vehicle and detects a tire air pressure value to determine the tire air pressure value. A transmitter for transmitting as a pneumatic signal, 31 is a receiver for receiving a signal from the transmitter with a built-in receiving antenna, and the plurality of receivers 31 are front wheels A.
1 and A2 and a rear wheel B1 and B2.

Reference numeral 4 is a control device such as a microcomputer for judging whether the tire pressure value output from the receiving device 31 is within a normal range, and 5 is a display device such as a liquid crystal for displaying the contents judged by the control device 4. is there.

FIG. 2 is a block circuit diagram of the transmitter 10. In FIG. 2, 11 is a pressure detecting means such as a sensor for detecting a tire air pressure value, and 12 is a tire air pressure signal. And a transmission control means such as a microcomputer, 13 is a high frequency transmission means such as an IC which modulates the tire pressure signal from the transmission control means 12 and transmits it as a high frequency signal, 14 is a transmission antenna for transmitting this high frequency signal, and 15 is a pressure A battery serving as a power source for the detection unit 11, the transmission control unit 12, and the high frequency transmission unit 13.

FIG. 3 is a block circuit diagram of the receiver 31. In FIG. 3, reference numeral 21 is a receiving antenna for receiving a high frequency signal from the transmitter, and 22 is a demodulator of this high frequency signal and outputs it as a tire pressure signal. High-frequency receiving means such as an IC, 23 is a reception control means such as a microcomputer that decodes the tire pressure signal, and 24 is an output means such as an IC that outputs a tire pressure value.

The transmission control means 12 of the transmission device 10 is registered with the identification number of each transmission device 10, and the reception control means 23 of the reception device 31 in the central portion between the front wheels A1 and A2 has a right side. The identification numbers of the transmitters 10 mounted on the front wheels A1 and the left front wheels A2 are the same as the rear wheel right side B1 in the reception control means 23 of the receiver 31 near the center of the rear wheels B1 and B2.
Also, the identification number of the transmitter 10 mounted on the rear wheel left side B2 is registered.

Further, the control device 4 is registered with the identification numbers of all four of these transmitting devices 10, the minimum tire air pressure value and the maximum tire air pressure value of each tire, and the tire air pressure detection system is constructed. .

In the above structure, the transmission control means 12 of the transmission device 10 mounted on each tire manages time, the pressure detection means 11 detects the tire air pressure value and outputs the value to the transmission control means 12.

Then, as shown in the wireless data format of FIG. 4, the transmission control means 12 has a synchronizing signal 25A for making a timing at which the receiving device reads the tire pressure signal, a registered identification number 25B, and a pressure detecting means. The tire air pressure signal having the tire air pressure value 25C output from 11 is converted and output, the high frequency transmitting means 13 modulates the tire air pressure signal into a high frequency signal, and the transmitting antenna 14 transmits this.

Then, the high-frequency signal from the transmitting device 10 is received by the receiving antenna 21 built in the receiving device 31, and the high-frequency receiving means 22 demodulates this high-frequency signal and outputs it to the reception control means 23 as a tire pressure signal. To do.

Next, the reception control means 23 uses the tire pressure signal input from the high frequency reception means 22 to determine the synchronization signal 2
Transmission device identification number 25B in synchronization with the signal of 5A
And read the tire pressure value 25C.

Then, the transmission device identification number registered in advance and the read transmission device identification number 25B are compared, and when they match each other, the transmission device identification number 25B and the tire pressure value 25C obtained by the reading are shown in FIG. The tire pressure signal is converted into a tire pressure signal as shown in the wired data format 5 and output to the control device 4 through the output means 24.

Further, the control device 4 compares the tire air pressure signal input from the output means 24 with the previously registered identification number of each transmitter and the transmitter identification number 25B included in the tire air pressure signal. Then, from which transmitter, that is, which tire the tire pressure signal of the tire is read, and the tire pressure minimum value or tire pressure maximum value of each tire of the vehicle that is registered in advance is included in the tire pressure signal. Tire pressure value 25
By comparing with C, it is determined for each tire whether or not the input tire pressure value is within the normal range.

If the determined content is not within the normal range, the display device 5 displays "abnormal tire pressure" or the like to notify the driver that the tire pressure is abnormal.

As described above, according to this embodiment, the tire pressure signals from the transmitters mounted on the respective tires of the vehicle are received by the plurality of receivers arranged near the transmitter and having the receiving antenna built therein. By configuring the tire pressure detection system so that the control device determines whether the tire pressure value is within the normal range based on this signal, a plurality of receiving devices having a receiving antenna receive signals from the transmitting device. Since the transmission distance of the high frequency signal output from the antenna is short and the influence of ambient noise can be reduced, expensive coaxial cables are not required, material costs are low, and a tire pressure detection system that can be easily wired is provided. It can be realized.

Further, since the transmitting device transmits the identification number of each transmitting device, the transmitting device also transmits the identifying number of each transmitting device in addition to the tire air pressure signal. Even when the tire pressure signal is received, the control device can determine from which transmitting device the tire pressure signal is transmitted, and the tire pressure of each tire can be reliably detected.

In the above description, each transmitting device 10
However, even if the identification number is not transmitted from the transmitting device 10, the control device 4 determines whether the tire pressure signal is the front tire pressure signal or the rear tire pressure signal in the connection state with the receiving device. Since these signals can be determined, the input tire air pressure value is compared with the front wheel A1, A2 by comparing those signals with the tire air pressure minimum value or tire air pressure maximum value of each tire of the vehicle registered in advance.
It is possible to determine whether it is within the normal range on the side or the rear wheels B1, B2.

(Second Embodiment) Using the second embodiment,
The invention will be described particularly in the inventions described in claims 3 and 4.

The same components as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

Also in the present embodiment, as shown in FIG. 1, the transmitter 10 mounted on each tire transmits the tire pressure value as a tire pressure signal, and the receiver 31 receives this signal and controls it. It is the same as in the first embodiment that the control device 4 determines the tire pressure value of this signal, and the display device 5 displays the determined content, which is output to the device 4.

The respective identification numbers are registered in the transmitter 10, and the transmitter 10 transmits the identification number and the tire pressure value as a tire pressure signal, as in the first embodiment.

However, in the first embodiment, the front wheels A1, A
In the receiving device 31 between the two, the identification numbers of the front wheels A1 and A2 are
The receiving device 31 between the rear wheels B1 and B2 has a configuration in which the identification numbers of the rear wheels B1 and B2 are registered, but in the present embodiment, between the front wheels A1 and A2 and between the rear wheels B1 and B2. Both receiving devices 31 of the front wheels A1, A2 and rear wheels B
The identification numbers of all four transmitting devices 10 of 1 and B2 are registered.

The tire pressure signal output from the receiving device 31 to the control device 4 is the identification number 25 in the case of the first embodiment as shown in the wired data format of FIG.
In addition to B and the tire air pressure value 25C, a reception level 25D that indicates the strength of the received radio wave from the transmitter 10 is also added.

Further, as in the case of the first embodiment, the control device 4 further includes the identification numbers of all the four transmitting devices 10 of the front wheels A1 and A2 and the rear wheels B1 and B2, and the minimum tire pressure value of each tire. In addition to the maximum tire pressure, etc., the transmitter 1
In order to prevent an erroneous determination from 0 to a reception state of the receiving device 31 being strong or weak, a reference reception level of a predetermined value or more is registered.

In the above configuration, when the tire pressure signal including the identification number and the tire pressure value is transmitted from the transmitter 10 mounted on each tire of the vehicle, as in the first embodiment, the front wheels A1, A2 side. The receiving device 31 on the rear wheel side also receives this, the receiving level 25D of each is added, and the signal is output to the control device 4.

The control device 4 is the receiving device 3 on the front wheel side.
From the signals input from both 1 and the receiving device 31 on the rear wheel side, the reference reception level registered in advance is compared with the two input reception levels 25D, and the input reception level 25D is registered. Only when the level is equal to or higher than the reference reception level, it is determined for each tire whether the input tire air pressure value is within the normal range, as in the first embodiment.

As described above, according to the present embodiment, the signal output from the receiving device is added to the receiving level indicating the strength of reception to output the signal to the control device, and the receiving level input to the control device is set in advance. By judging the tire pressure signal only when it is equal to or higher than the registered reference reception level, the control device makes a judgment using a good tire pressure signal having a predetermined strength, and thus a tire with few erroneous judgments. It is possible to realize an air pressure detection system.

In the above description, the receiving device 31 outputs the signal from the transmitting device 10 by adding the reception level 25D to the signal, but the reference receiving level is registered in the receiving device 31 in advance and reception is performed. The device 31 compares the input reception level 25D with the registered reference reception level, and outputs the tire pressure signal to the control device 4 only when the input reception level 25D is equal to or higher than the reference reception level. However, the present invention can be implemented.

Further, in a situation where interference of radio waves to be received occurs due to rotation of tires or changes in use environment, and a change in reception level occurs, tire pressure signals from the transmitters 10 of the front wheels A1 and A2 are received. The reception level of the reception device 31 on the front wheels A1, A2 side may be low and the reception level of the reception device 31 on the rear wheels B1, B2 side may be high. In that case, the control device 4 has a high reception level 25D. If the tire pressure signal of the other receiving device 31 is used to determine for each tire whether the tire pressure value is within the normal range, the control device has a tire pressure signal having a higher reception level among a plurality of signals. Since the determination is made in step 1, more reliable determination can be performed.

Furthermore, in the above description, a system in which a plurality of receiving devices 31 are connected in parallel to the control device 4 as shown in FIG. 1 has been described, but each transmitting device 10 signals each tire of the vehicle to a signal. When the transmission is performed by adding distinguishable identification numbers, the outputs of a plurality of receiving devices can be superimposed on one signal line in time series, so that a plurality of receiving devices 41 are connected in series as shown in FIG. The system may be an integrated system.

[0050]

As described above, according to the present invention, there is an advantageous effect that it is possible to obtain a tire pressure detection system which is inexpensive and easy to assemble.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a tire air pressure detection system according to a first embodiment of the present invention.

FIG. 2 is a block circuit diagram of the transmitter.

FIG. 3 is a block circuit diagram of the receiving device.

FIG. 4 is a diagram showing the wireless data format.

FIG. 5 is a diagram showing the same wired data format.

FIG. 6 is a diagram showing a wired data format according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of a tire air pressure detection system according to another embodiment.

FIG. 8 is a block diagram of a conventional tire pressure detection system.

[Explanation of symbols]

1,10 transmitter 4 control device 5 Display device 11 Pressure detection means 12 Transmission control means 13 High frequency transmitter 14 transmitting antenna 15 batteries 21 receiving antenna 22 High frequency receiving means 23 Reception control means 24 Output means 25A sync signal 25B transmitter identification number 25C tire pressure value 25D reception level 31,41 receiver

Claims (4)

[Claims] 1. A transmitter mounted on each tire of a vehicle for detecting a tire pressure value and transmitting the detected tire pressure value as a tire pressure signal; and a receiver having a receiving antenna for receiving a signal from the transmitter. A tire air pressure detection system comprising: a control device that determines whether a tire air pressure value output from the receiving device is within a normal range, and a plurality of the receiving devices, each of which is arranged near the transmitting device. 2. The tire pressure detection system according to claim 1, wherein the transmitter transmits the identification number of each transmitter. 3. The signal output from the receiving device is added to the reception level indicating the strength of reception to output the signal to the control device, or
The tire air pressure detection system according to claim 2, wherein only a signal having a predetermined reception level or higher is output to the control device. 4. The tire pressure value is determined using a tire pressure signal having a large reception level among the signals input by the control device, while the plurality of receiving devices output the reception level indicating the strength of reception. The tire pressure detection system according to claim 2.