JP3457160B2 - Tire pressure warning device - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is used in automobiles. TECHNICAL FIELD The present invention relates to an improvement in a device that constantly detects tire air pressure during traveling of a vehicle and gives an alarm when an abnormality occurs. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device in which a sensor for detecting tire pressure is provided on a tire and wireless information, that is, electromagnetic waves, is used to transmit air pressure information to a control device installed in a vehicle. The present invention was developed as a device suitable for a large vehicle having a large number of tires, but can be applied to a device other than a large vehicle.

[0002]

2. Description of the Related Art A technique in which a tire pressure is constantly detected by a pressure sensor while a vehicle is running, the detection result is transmitted by a radio signal, and the radio signal is received and detected by a receiving device provided on the vehicle side. It has been known. The applicant of the present application has disclosed such an art in which a pressure sensor provided on a tire does not require a battery for a power source (refer to Japanese Patent Laid-Open No. 5-104917, hereinafter referred to as “prior invention”). . This prior invention is to form a resonance circuit by combining a capacitance element whose capacitance changes according to the tire pressure as a pressure sensor and an inductance, and replace the change in tire pressure with the change in the resonance frequency of the resonance circuit. By transmitting a radio wave from the vehicle side, this is resonated to obtain air pressure information.

Further, there is known a device in which a transmission circuit provided with a battery is individually arranged in a tire and a radio wave signal is generated in accordance with tire pressure information (Japanese Patent Laid-Open No. 8-17878).
4 publication). This device prepares a detection device that the driver can carry by hand, and receives the weak radio wave generated by the transmission circuit when the detection device is brought close to the tire.

There is also known a technique in which a radio wave signal transmitted by a pressure sensor provided on a tire is used in common with a radio wave signal emitted by a radio wave key for a vehicle door lock (JP-A-6-2).
No. 47114). In connection with this conventional technique, the above-mentioned reference discloses a technique in which the output of the tire air pressure sensor is guided by a wire to a transmitter attached to the wheel. Also in this technique, it is understood that the transmitter is equipped with a power supply circuit using individual batteries.

[0005]

The inventor of the present application has studied a tire pressure warning device that can be applied to large vehicles. The invention of the prior application has an excellent feature that the circuit on the tire side is simplified because no battery is provided on the tire side, but it is not suitable for a large vehicle having a large number of tires. That is, in the invention of the prior application, the tire side device resonates because the tire side device receives the electromagnetic wave transmitted from the vehicle side antenna and the resonance circuit provided in the tire side device resonates with the electromagnetic wave. The electromagnetic waves emitted from the tire side are sometimes extremely weak. Therefore, in a vehicle having a small number of tires, for example, a passenger car, it is possible to arrange the antennas close to the respective tires, but in a large vehicle having a large number of tires, the number of antennas becomes large and the vehicle side device It turns out that the composition of is complicated.

[0006] In general, there are large-sized vehicles in which four or more tires are provided on one shaft. With such a structure, even if the air pressure of one of them drops, the driver can perceive it by the sense. The tire pressure warning device is required only for the vehicle having such a structure.

On the other hand, the technique of providing a battery power source to the tire side device is a known technique as described above, but the present invention has sought a battery having a configuration as small as possible and not requiring battery replacement. That is, we have sought to shorten the time for transmitting electromagnetic waves as much as possible, suppress battery consumption as much as possible, and make the vehicle life longer than the tire life.

Further, in the case of a large-sized vehicle where the total number of tires is more than ten, even if a warning that the tire pressure has dropped is given, the driver can recognize which tire it is. Need to do so. Generally, it is possible to display the position of this tire on the driver's seat on the panel, but it is rare that a tire pressure drop occurs, and in order to display this on the driver's seat, a display space is provided in the driver's seat. It is not appropriate to provide it.

Further, the tires are equipped when the vehicle is manufactured, but they are relatively frequently replaced with the operation of the vehicle after that, and a complicated setting registration procedure is executed every time the vehicle is replaced. It is not appropriate to do. Furthermore, when the device installed on the tire autonomously transmits electromagnetic waves and the device installed on the vehicle body receives the electromagnetic waves to monitor the tire pressure, a truck base where many vehicles of the same vehicle type are deployed. For example, the alarm should not be confused by the reception of electromagnetic waves from the tires of other vehicles parked nearby or of other vehicles approaching.

The present invention has been made against such a background, and an object thereof is to provide a tire pressure warning device applicable to a large vehicle having a large number of tires. It is an object of the present invention to provide a tire pressure warning device that can cope with the number of tires, which is tens.

It is an object of the present invention to provide a device for displaying to a driver's seat that an electromagnetic wave from the sensor device of a specific tire cannot be received due to a failure of the sensor device mounted on the tire. It is an object of the present invention to provide a device that can identify a sensor device in which a failure has occurred by a simple operation performed by a driver.

[0012]

SUMMARY OF THE INVENTION According to the present invention, the air pressures of all the tires mounted on a vehicle are detected at regular intervals during running, and the tire pressure and its air pressure information are transmitted to a control device by electromagnetic waves. However, when the control device cannot receive the electromagnetic wave, the sensor device displays a failure alarm on the driver's seat as a failure.

That is, the present invention provides a sensor device which is mounted on a wheel and which transmits an electromagnetic wave modulated by a signal containing air pressure information of a tire mounted on the wheel, a receiver which is mounted on a vehicle and receives the electromagnetic wave. In a tire air pressure alarm device comprising a control device including an alarm means for issuing an alarm according to the air pressure information obtained in the receiver output, the sensor device includes a pressure sensor for detecting tire air pressure, and a cycle. A clock circuit that generates a trigger signal at t1 (for example, 15 minutes) and a time t2 (<< t1, for example, 200 milliseconds) according to the trigger signal.
A pulse train signal generating circuit for generating a frame pulse including an identification code (ID) and output information of the pressure sensor, and the control apparatus registers the identification codes of all the sensor devices mounted on the vehicle. And a means for issuing a sensor failure alarm when one of the identification codes registered in the registering means is not received for a period of n times the cycle t1 (n is an integer). .

In the control device, a means for judging a sensor failure and an audible audible alarm are continuously sounded and the audible alert is temporarily interrupted each time one of the identification codes registered in the registering means is received. Preferably, the sensor device includes a manual switch and a means for sending the trigger signal when the manual switch is operated.

The sensor device is a spare device mounted on a vehicle.
Mounted on each and every tire including tires.
In each sensor device, a pressure sensor detects a tire pressure, and a pulse train signal generation circuit generates a frame pulse (including an identification code and output information from the pressure sensor for a time t2 in accordance with a trigger signal of a period t1 generated from a clock circuit). A healthy signal) is generated, and this is modulated and transmitted as an electromagnetic wave.

The control device receives the healthy signal transmitted by this electromagnetic wave and registers the identification codes of all the sensor devices mounted on the vehicle. When one of the registered identification codes is not received for a period of n times (for example, 3 times) the cycle t1, the sensor device is in a failure state, and it is determined that the healthy signal cannot be transmitted. It is sent to the alarm means provided.

This failure alarm is sent immediately when one of the registered identification codes is not received for a period of an integral multiple (for example, 3 times) of the cycle t1. Due to the occurrence of this failure alarm, the driver operates the manual mode setting switch, for example, the mode setting button of the momentary switch continuously for a predetermined number of times (for example, 5 times), and the failure sensor specifying mode is set. In this fault sensor identification mode,
The control device continuously emits an audible alarm, and each time it receives one of the identification codes registered in advance by the healthy signal, the audible alert is temporarily interrupted each time it receives the identification code. Let the driver recognize that the sensor device is normal. When the push button of the fault sensor device is pressed, the audible alarm continues.

On the other hand, the frame pulse including the identification code from the sensor device and the output information from the pressure sensor is transmitted when a manual switch provided in the sensor device is operated. Therefore, if the audible alarm is not interrupted when the manual switch provided in the sensor device is operated, it can be considered as a failure, and the driver can easily identify the sensor device in which the failure has occurred. be able to.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The following modes are set in the control device of a tire pressure warning device according to the present invention.

1) Holding wheel number storage mode 2) Initial setting mode 3) Abnormal tire detection mode 4) Warning generation mode 5) Tire specifying mode 6) Failure sensor specifying mode The holding wheel number storing mode is a manual mode setting switch, For example, it is set by operating the mode setting button of the momentary switch for a predetermined time (for example, 3 seconds). In the retained wheel number storage mode, the total number of wheels of the vehicle input by operating the mode setting button is registered, and the total number of wheels is acoustically displayed when the registration is completed.

The initial setting mode is set by operating the mode setting button for a predetermined time (for example, 2 seconds). In this initial setting mode, a signal transmitted by individually operating the manual switch of the sensor device is received, and the identification code of the sensor device included in this signal is registered together with the wheel number of the vehicle. Each time the registration of the identification code is completed, acoustic signals are generated by the number indicating the wheel number. For example, if the tire is the first tire, the acoustic noise is made once, and if it is the fifth tire, the acoustic noise is made five times. Thereby, the driver can surely grasp the number of wheels for which the identification code registration is completed.

When the identification code is registered, the manual switch of each sensor device is operated, and the timer switch for generating the cycle t1 incorporated therein is reset in accordance with this operation, so that the healthy signal generation cycle after that. At t1, the operation time is the start time.

In the abnormal tire detection mode, a predetermined time (for example, 3
(Seconds) is set when the operation is received. In this abnormal tire detection mode, the control device sends a cycle t1 from the sensor device.
The health signal transmitted each time is received, and it is determined whether the registered bit is "1", that is, whether the tire pressure is normal. If "1" is indicated, the tire pressure is normal and the tire pressure detection mode is continued.

The alarm generation mode is set when "0" is shown in the registration bit of the healthy signal in the tire air pressure detection mode, that is, when there is a wheel whose tire air pressure is below a predetermined value. . In this alarm generation mode, the identification code of the tire registered at the initial setting is identified, and an alarm indicating that there is an abnormal pneumatic tire is generated.

The tire specifying mode is set when this alarm is issued. In this tire identification mode, in order for the driver to identify an abnormal tire when an alarm is issued, the manual switch of the sensor device provided on each tire is sequentially operated, and the manual switch of the tire with an abnormality is pressed. Sound alarm when This allows the driver to easily identify the abnormal tire.

When the healthy signal from the sensor device is not received, the control device confirms the identification code of the sensor device which does not transmit the healthy signal, records the occurrence of the failure, and continues the failure alarm.

The failure sensor specifying mode is set when the manual mode setting switch, for example, the wheel number setting button of the momentary switch is continuously operated a predetermined number of times (for example, 5 times) as described above. In this fault sensor identification mode, the identification code of a sensor device that does not transmit a healthy signal is confirmed, and an audible alarm is generated when the push button of the corresponding sensor device is pressed.

When no signal arrives from any of the sensor devices, the arrival of signals from all the sensor devices cannot be stopped at the same time, so an alarm is issued as a failure on the receiving side.

[0029]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a block diagram showing a configuration of a main part of a sensor device in an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a main part of a control device in an embodiment of the present invention, and FIG. 3 is a system according to the embodiment of the present invention. FIG. 4 is a plan view of the vehicle chassis showing the overall configuration of FIG. 4, and FIG. 4 is a diagram showing the system configuration of the control device in the embodiment of the present invention.

In the embodiment of the present invention, a sensor device 1 mounted on a wheel (not shown) for transmitting an electromagnetic wave modulated by a signal containing air pressure information of a tire 31 mounted on the wheel, and a sensor device 1 mounted on a vehicle for transmitting this electromagnetic wave. There is provided a receiver and a control device 2 including an alarm means 3 for issuing an alarm in accordance with air pressure information obtained at the output of the receiver.

As shown in FIG. 1, the sensor device 1 includes a microprocessor (MPU) 10, a pressure sensor 11 that detects tire air pressure and outputs the detected output to the microprocessor 10, and a cycle t1 ( For example, a clock circuit 12 that generates a trigger signal in 15 minutes), a manual switch 13 that opens and closes by operating a push button 13a, a timer switch 14 that starts a timer when the manual switch 13 is operated, E ² PROM or EEPRO in which the identification code of the tire 31 is stored in advance
M15, a modulator 16 for modulating the pulse train signal sent from the microprocessor 10, and the modulator 16
An oscillator 18 for transmitting the output of the above as a radio signal from the antenna 17 and a battery 19 are provided.

In the microprocessor 10, according to the trigger signal generated by the clock circuit 12, a pulse train for generating a frame pulse including an identification code and output information of the pressure sensor 11 for a time t2 (<< t1, eg, 200 milliseconds). Signal generation circuit and manual switch 13
Generates a frame pulse when the
Means for resetting the switch 14 are included.

As shown in FIG. 2, the control device 2 includes a receiver 22 for receiving electromagnetic waves from the sensor device 1 via the antenna 20 and the coaxial cable 21, and this receiver 22.
A digital analyzer 23 for analyzing the received digital signal, a momentary switch 24 for manually setting the mode and the number of wheels, and an alarm signal generation control according to the tire pressure information analyzed by the digital analyzer 23. A program control circuit 25 and a memory 26 are provided.

Further, in the control device 2, a means for registering the identification codes of all the sensor devices 1 mounted on the vehicle and a means for registering this for a period of n times the cycle t1 (n is an integer). Means for issuing a sensor failure alarm when one of the identified identification codes is not received, means for setting a sensor test mode by operation, and means for continuously sounding and registering an acoustic alarm in this sensor test mode. Means for temporarily suspending the audible alarm each time one of the identification codes registered in 1 is received.

The alarm means 3 shown in FIG. 2 is provided with an indoor buzzer 4 and an outdoor buzzer 5 which perform acoustic display for other notifications including alarms, and a lighting display and a blinking display for other notifications including alarms. And a display lamp 6 for performing the operation.

In accordance with the operation of the momentary switch 24, the program control circuit 25 of the control device 2
With the initial setting mode set, a plurality of identification codes are assigned to the tires 3 of the vehicle from electromagnetic waves received within a period t1.
No. 1 as an identification code, a means for registering the tire identification code of the vehicle for the number of tires set by the momentary switch 24, and a means for generating an acoustic signal each time the registration of the tire identification code is completed. And means for acoustically displaying the registered number of tires when the registration of the number of tires is completed.

Further, as shown in FIG. 4, the control device 2 receives the outputs of the vehicle speed sensor 8, the key switch 30, the momentary switch 24, the alarm reset switch 29 and the diagnostic switch 47, and the indoor buzzer 4 The display output is sent to the outdoor buzzer 5, the display lamp 6 and the diagnostic monitor 7. The diagnosis switch 47 is operated when performing a failure diagnosis of the sensor device 1, the control device 2, and the antenna 20, and the diagnosis result is displayed on the diagnosis monitor 7.

FIG. 5 is a front view showing the external shape of the sensor device in the embodiment of the present invention, FIG. 6 is a front view showing the internal structure of the sensor device in the embodiment of the present invention, and FIG. 7 is a view of the sensor device in the embodiment of the present invention. 6 is an enlarged sectional view taken along the line AA shown in FIG. 6, and FIG. 8 is a sectional view taken along the line B- shown in FIG.
FIG. 9 is an enlarged sectional view of B, and FIG. 9 is an enlarged sectional view showing the structure of the manual switch incorporated in the sensor device according to the embodiment of the present invention.

The sensor device 1 is housed in the case 33, and the case 33 is fixed to the tire valve 34. The tire valve 34 is connected by a mounting nut 35 so as to communicate with the tire 31. The pressure sensor 11 includes a bellows 37 that expands and contracts due to changes in air pressure, and the bellows 37.
A contact 38 fixed to the inner surface of the head of the tire, and a conduction terminal 40 that contacts the contact 38 and sends an electric signal to the circuit board 39 when the air pressure exceeds a predetermined value. Is located in.

The push button 13a of the manual switch 13 and the tire valve 34 are arranged so as to project outside the case 33, and the antenna 17 is fixed to the protruding portion of the tire valve 34. The circuit board 39 includes the microprocessor (MPU) 10, the clock circuit 12, the timer switch 14, the E ² PROM or EEPROM 15, the modulator 16 and the oscillator 18 described above. An identification code unique to the sensor device 1 mounted on each tire 31 is engraved on the surface of the case 33.

The manual switch 13 is, as shown in FIG.
Case 49 and switch board 4 housed in the case 40
1, an opening / closing switch 42, a rubber diaphragm 43, an O-ring 44 and a spring 45, and a rubber cap 46 that contains a housing 49 and transmits the pressing force to the rubber diaphragm 43 when the push button 13a is pressed. It is composed of The open / close switch 42 is a switch in which conductive rubber is brought into contact with the pattern of the switch substrate 41 to be conductive when the rubber cap 46 is pressed, or another switch which is mechanically turned on when pressed. Used.

FIG. 10 (a) is a diagram showing a state in which the sensor device according to the embodiment of the present invention is mounted on a wheel, and FIG. 10 (b) is a partially enlarged view of the sensor device portion. The sensor device 1 is fixed using a belt 36 so as to be pressed from the wheel inner surface line side toward the wheel outer surface line side indicated by the arrow.

FIG. 11 is a perspective view showing the operation surface of the momentary switch according to the embodiment of the present invention. The momentary switch 24 has the number of wheels (number of tires) of the vehicle.
There is provided a mode setting button 24a for setting the number of retained wheels storage mode by operation when storing the number of wheels, and a number of wheels setting button 24b for inputting the total number of retained wheels by operation after setting the storage mode for the number of retained wheels. This mode setting button 2
4a and the wheel number setting button 24b are turned on when a finger is pressed to send a setting signal, and when the finger is released, they are automatically returned and turned off.

FIG. 12 is a diagram showing the structure of the main part of the antenna on the control device side in the embodiment of the present invention. The antenna 20 arranged on the control device 2 side is formed by a loop-shaped receiving antenna wire, and the connection portion with the coaxial cable 21 is covered with a waterproof case 48. As shown in FIG. 3, a plurality of the antennas 20 are arranged in the chassis of the vehicle.

FIG. 13 is a diagram for explaining the shape and size of the control device in the embodiment of the present invention. The control device 2 shown in FIG. 2 is housed in a housing 2a, D = 120 mm,
The size is about W = 100 mm and Z = 30 mm.

Here, the transmission frame generated by the pulse train signal generation circuit will be described. FIG. 14 is a diagram showing the structure of a transmission frame in the embodiment of the present invention. The numbers in the figure are the number of bits.

The sensor device 1 is provided with a unique identification code (ID) for distinguishing it from other wheels. This identification code is composed of 25 bits, and the No.
1 to No. Up to 33,554,431 (= 2 ²⁵ -1) are given. Therefore, if this number is exceeded, the No. The number is returned to 1 and the same number is repeatedly given, but since the number of digits is extremely large, there is no practical overlap.

The frame used in this embodiment is shown in FIG.
As shown in FIG. 5, it is divided into 5 blocks, a synchronization bit (10 bits), a start bit (2 bits), a first,
Second and third identification code (ID) codes (7 bits each), fourth identification code (ID) code (4 bits), stop bit (1 bit), registration bit (1 bit),
Switch bit (1 bit) and parity bit (1
The total time is 50 ms, and the time required for transmission is 40 milliseconds per frame.

The sync bit is composed of a combination of "0" and "1" and is used for clarifying where the frame starts when transmitting and receiving. If the identification code (ID) code is “zero”, all the bits of the first identification code (ID) code to the fourth identification code (ID) code are “0”, so the maximum “0” is 7 In succession. Therefore, at least "0" is required to recognize the beginning of the signal.
The identification bit that continues 8 times is required. As for the bits used in the present embodiment, each block is composed of 10 bits as shown in FIG. 14, and accordingly, the synchronization bit is provided with 10 bits in which 10 "0" s are arranged.

Since one block of the identification code (ID) code is composed of 10 bits, 25 identification code codes are divided into four blocks. When the control device 2 receives the divided identification code, it restores it and recognizes it.

FIG. 14A shows a start bit. In order to make it easier to recognize the beginning of the signal, it is arranged at the beginning of each block and is represented by "11". (B) is a stop bit which indicates the end of each block and is represented by "1". (C) is a registration bit, which is "1" at the time of transmitting the initial setting signal and "0" at the normal time. (D) is a switch bit and is represented by "1" when the tire air pressure is normal, and by "0" when it is below a predetermined value. (E) is a parity bit that represents the parity result of the identification code. By comparing this parity before the controller 2 compares the identification code,
The processing can be simplified and the reliability of the signal processing can be improved by the double processing.

Next, the operation of the embodiment of the present invention thus constructed will be described.

The feature of the present invention is that the sensor device 1 detects the air pressure of the tire 31 by the pressure sensor 11, and according to the trigger signal from the clock circuit 12,
A frame pulse (healthy signal) including the pressure information detected from the pulse train signal generation circuit and the identification code (ID) of the sensor device 1 is generated, the control device 2 receives this frame pulse and registers the identification code, and the cycle t1 (Eg 15
It is to issue a sensor device failure alarm when one of the registered identification codes is not received for a period of n times (minutes) (n is an integer, for example, 3).

The sensor device 1 is equipped with all the wheels 3 of the vehicle.
1 is equipped separately. Therefore, the control device 2 stores the number of wheels owned by the wheels 31 mounted on the vehicle, and stores the identification code corresponding to each wheel number.

First, the possessed wheel number storage mode by the control device 2 will be described. FIG. 15 is a flow chart showing the flow of operation in the retained wheel storage mode by the control device in the embodiment of the present invention.

When the control device 2 is activated by operating the key switch 30 and the mode setting button 24a of the momentary switch 24 is continuously operated for 3 seconds or more, the program control circuit 25 causes the number of wheels possessed by the vehicle ( Number of tires)
Is set, and the display lamp 6 is blinked every 0.3 seconds to indicate that the retained wheel number storage mode has been set.

When the wheel number setting button 24b of the momentary switch 24 is operated in accordance with this display and the mode setting button 24a is operated after the total number of possessed wheels is input, the number of wheels input by this operation is changed. The total number of wheels of the vehicle is stored in the memory 26. The total number of owned wheels is set as one wheel if the wheel number setting button 24b is operated once and as two wheels if operated twice. For example, if the vehicle has 13 wheels, the mode setting button 24a is set to 1 after operating 13 times. By being operated, the total number of wheels 13 is input.

When the total number of wheels is input and stored in this way, the control circuit 2 displays the total number of wheels input by the indoor buzzer 4, the outdoor buzzer 5 and the display lamp 6 three times.
The display of the stored total number of wheels is as shown in FIGS.
It is performed as shown in. The figure (a) is one wheel, (b) is two
The figure shows a display example of six wheels, (c) is six wheels, and (d) is twelve wheels. For example, in the case of six wheels, as shown in FIG. 7C, a slightly long sounding and lighting indicating five wheels and a short sounding and lighting indicating one wheel are repeated three times. Further, in the case of 12 wheels, as shown in FIG. 3D, a short sounding and lighting of one wheel is made to be continuous twice after making a slightly long sounding of 5 wheels in succession. Repeat 3 times.

The display by the indoor buzzer 4, the outdoor buzzer 5 and the display lamp 6 enables the driver to confirm that the total number of wheels of the vehicle has been input and stored.

When the control device 2 completes the setting process of the total number of wheels, the control device 2 changes the lighting of the indoor buzzer 4, the outdoor buzzer 5 and the display lamp 6 to a cycle of 1 second and sets the initial setting mode. .

Next, the operation of transmitting the identification code by the sensor device 1 in the initial setting mode will be described. When the push button 13a of the sensor device 1 is operated for 2 seconds or more, the manual switch 13 is turned on, and a start signal is sent from the battery 19 to the microprocessor 10, the modulator 16 and the oscillator 18. The microprocessor 10 resets the timer switch 14 by this activation signal.

At the same time, the detection output of the pressure sensor 11 is taken in, and the identification code of the sensor device 1 stored in advance in the E ² PROM or EEPROM 15 is read out, and a frame pulse containing this identification code and the air pressure information of the tire 31 is read. Is generated by the pulse train signal generation circuit, modulated by the modulator 16 at the period t1 set by the timer switch 14, and transmitted from the oscillator 18 as an electromagnetic wave through the antenna 17 for a time t2 (200 milliseconds).

FIG. 17 is a diagram showing the structure of a frame transmitted from the sensor device according to the embodiment of the present invention. This shows only the block 5 of the frame described with reference to FIG. 5 is an example when the air pressure of the sensor device 1 of 5 is normal. In this way, in the transmission frame at the time of initial setting, the registration bit indicated by diagonal lines is transmitted with "1".

The frame thus configured is transmitted as a healthy signal for five frames as shown in FIG.
This transmission is continued from when the push button 13a is operated until the electric energy of the battery 19 is exhausted. If the transmission time of one frame is 40 milliseconds, the transmission time t2 per transmission is 200 milliseconds for five frames. If the transmission cycle t1 is set to 15 minutes based on the past results, the life of the battery 19 is longer than the life of the vehicle. Therefore, the battery 19 can be used without being replaced until it is discarded. it can.

Since the transmission cycle t1 is the start time when the push button 13a is operated, the push button 13a is next.
Until is operated, the same cycle t1 is repeated with the first operation as the start time.

FIG. 19 is a diagram showing the frame structure of the block 5 of the healthy signal in the embodiment of the present invention. In this example, the wheel number No. 5 shows the configuration of tire No. 5 when the tire pressure is normal. The frame pulse from the sensor device 1 at the time of initial setting is transmitted with the registration bit being "0". The control device 2 recognizes that the frame pulse is transmitted from the sensor device 1 by confirming the registration bit “0”.

Next, the identification code registration operation by the control device 2 in the initial setting mode will be described. FIG. 20 is a flow chart showing the flow of the identification code registration operation by the control device in the embodiment of the present invention.

When the control device 2 receives the frame pulse transmitted by the operation of the push button 13a of the sensor device 1, the control device 2 stores 50 bits for the first one frame in the memory 26 and sequentially transmits two frames to five frames. The parity up to the frame and the parity of the first frame stored are determined. If the parity determination result is correct, the ID code in the buffer is compared with the ID code in the memory. If they match, the transmitted data is regarded as normal, and the transmitted identification code is registered in the memory 26. If the parity determination result is not correct, frame pulse reception is repeated and continued until the determination is correct.

Each time the control device 2 registers the identification code,
The indoor buzzer 4 emits a buzzing sound indicating the number of the rings.
And it is generated from the outdoor buzzer 5. That is, if the number of rings is the first, one beeping sound is generated as shown in FIG. 16 (a), and if it is the second, the number is 2 as shown in FIG.
Generates a single beeping sound. Also, if it is the sixth, the same figure (c)
The sounding sound is generated in the form shown in (1), and the sounding sound is generated in the form shown in FIG. As a result, the number of rings for which the identification code has been registered can be confirmed.

When the input operation of the identification codes for all the wheels mounted on the vehicle is completed, the mode setting button 24a of the momentary switch 24 is operated for 3 seconds. When the control device 2 receives this operation input, it compares the final number of wheels at the time of inputting this identification code with the total number of wheels stored at the time of inputting the number of possessed wheels, and if the number is the same, it identifies all the wheels. The registration of the code is considered to be completed, the initial setting mode is released, the blinking of the display lamp 6 and the buzzing of the indoor buzzer 4 and the outdoor buzzer 5 are stopped, and the abnormal tire detection mode is set.

If the identification codes for all the wheels have not been registered, the indicator lamp 6 continues to blink and the sounds of the indoor buzzer 4 and the outdoor buzzer 5 are changed to, for example, "beep, blip, ..." To do. When the push button 13a is operated again for 2 seconds or more by this sounding, the indoor buzzer 4 and the outdoor buzzer 5 are made to sound like "pee, pee, ..." with a cycle of 1 second, and all the sensor devices 1 are registered. The same operation is repeated until the end.
When the key switch 30 is turned off, the control operation of the control device 2 is stopped.

In this way, when the sensor device 1 and the control device 2 perform the initial setting including the stored number of wheels and the identification code, the identification code and the output of the pressure sensor 11 are output at a constant cycle t1 (200 milliseconds). A frame pulse containing information is continuously transmitted from the sensor device 1 as a healthy signal by electromagnetic waves.

Now, the operation of detecting the air pressure and generating the alarm signal by the sensor device 1 will be described.

Pressure sensor 11 provided in the sensor device 1
Is a threshold value for which the air pressure of the tire 31 is set (for example,
When it becomes 7.0 ± 0.5 kgf / cm ² ) or less, the bellows 37 shown in FIG. 7 expands, and the contact which was in contact with the conduction terminal 40 in the normal state and was in the on state is opened to be in the off state.

Upon receipt of this off signal, the microprocessor (MPU) 10 receives the E ² PROM or EEPRO.
The identification code (ID) stored in M15 is read and an alarm frame including this identification code is generated.
This alarm frame is formed by 15 frames only for the first transmission so as not to overlap with the healthy signal transmitted from the sensor device 1 of another wheel as shown in FIG. FIG. 22 shows only the block 5 of one frame. When the tire pressure is below the threshold value, the switch bit indicated by the diagonal line is set to "0".

The sensor device 1 modulates the alarm frame formed by the 15 frames and transmits it as an electromagnetic wave. After the first transmission, similar to the healthy signal, the transmission of 5 frames is repeated at a cycle t1 (15 minutes) until a measure such as replacement with a spare tire is taken.

FIG. 23 is a flow chart showing the flow of the abnormal tire detection operation by the control device in the embodiment of the present invention.

Since the abnormal tire detection mode has already been set by the operation input, when the control device 2 receives the healthy signal from the sensor device 1, it determines whether or not the alarm frame is composed of 15 frames. . If it is an alarm frame, it is determined whether or not "0" is indicated in the switch bit.

When the switch bit is "0", the electromagnetic wave is received when the wheel is not rotating or when the sensor device 1 mounted on the tire enters a certain range on the circumference when the vehicle is traveling at low speed. Since the situation becomes impossible, the detection output from the vehicle speed sensor 8 is taken in and it is determined whether or not the vehicle speed exceeds 5 km / h. If it exceeds 5 km / h, it is assumed that the electromagnetic wave from the sensor device 1 has been reliably received, and the vehicle speed flag is set and the alarm generation mode is set.
This vehicle speed flag remains set even if the vehicle speed falls below 5 km / h after being set, and the alarm generation state is maintained.

FIG. 24 is a flow chart showing the flow of the alarm generation operation by the control device in the embodiment of the present invention.

When the alarm generation mode is set, the control device 2 blinks the display lamp 6 every 0.5 seconds, and
The indoor buzzer 4 beeps to generate an alarm, prompting the operator to take measures against the abnormal pneumatic tire. The driver can recognize that the tire pressure is abnormal by this alarm. At this time, the control device 2 sets the tire specifying mode.

FIG. 25 is a flow chart showing the flow of the abnormal pneumatic tire specifying operation in the embodiment of the present invention.

When the control device 2 sets the tire specifying mode, the driver confirms the abnormal pneumatic tire.
This confirmation is performed by sequentially operating the push buttons 13a of the sensor device 1 mounted on each tire. When the control device 2 sequentially receives the confirmation operation signals and operates the push button 13a of the abnormal pneumatic tire, the control device 2 sounds the outdoor buzzer 5 for one second to display that the tire has an abnormal pneumatic pressure. This allows the driver to identify the abnormal pneumatic tire.

When the tire identified as having an abnormal air pressure is replaced with a spare tire and the push button 13a of the sensor device 1 is operated, the identification code and the air pressure information are transmitted by electromagnetic waves as frame pulses. . The control device 2 receives this frame pulse and overwrites the identification code of the abnormal tire stored in the memory 26 with the identification code of the spare tire. Since the identification code of the abnormal tire is erased by this overwriting, even if the transmission of the frame pulse is continued from the sensor device 1 of the abnormal pneumatic tire, it is not the target of control and no alarm is issued. When the control device 2 newly registers the identification code in this way, the vehicle speed flag is reset, the alarm generation mode is released, and the abnormal tire detection mode is set. After that, the detection operation is performed by receiving the healthy signal.

Next, the sensor failure judgment operation by the control device 2, which is a feature of the present invention, will be described. Figure 2
6 is a flow chart showing the flow of the sensor device failure judgment operation by the control device in the embodiment of the present invention.

The control device 2 determines whether or not a healthy signal from each sensor device 1 has arrived, and when there is a sensor device 1 that does not receive a healthy signal, it records that sensor device as a failure. The display lamp 6 is continuously turned on and the indoor buzzer 4 is continuously sounded to generate a failure alarm. At the same time, 7 segments 8 in the driver's seat
The identification code of the sensor device is displayed on the digit display for 3 seconds. When there are a plurality of sensor devices 1 to which the identification code has not arrived, the display is performed in order from the youngest identification code.

When the driver recognizes the occurrence of the sensor device failure according to the failure alarm and the alarm reset switch 29 is operated, the control device 2 causes the indoor buzzer 4 to operate.
Is stopped, and the lighting of the display lamp 6 is continued as it is. When the driver turns on the alarm reset switch 29 to specify the failure occurrence sensor device and the wheel number setting button 24b of the momentary switch 24 is operated five times in succession, the failure sensor identification mode is set. To set.

FIG. 27 is a flow chart showing the flow of the fault sensor specifying operation by the control device in the embodiment of the present invention.

In this failure specifying mode, the control circuit 2
The display lamp 6 blinks at intervals of 0.5 seconds, and the indoor buzzer 4 and the outdoor buzzer 5 sound at intervals of 0.5 seconds. Here, the driver operates the push button 13a of each sensor device 1 to confirm the transmission of the frame pulse.

The control device 2 determines whether or not a frame pulse has arrived from each sensor device 1 by this confirmation operation. If a frame pulse has arrived, the display lamp 6 is stopped for 2 seconds and then blinks at 0.5 second intervals, and at the same time, the indoor buzzer 4 and the outdoor buzzer 5 are stopped for 2 seconds and then 0.5 Sounds at intervals of seconds. By stopping for 2 seconds, the driver can confirm that the sensor device 1 is normal.

When the frame pulse does not arrive, the sensor device 1 is in the transmission disabled state or the ID code is destroyed, so that the display lamp 6 continues to blink at 0.5 second intervals, and The sounds of the indoor buzzer 4 and the outdoor buzzer 5 are continued as they are. Thereby, the driver can specify that the sensor device 1 is out of order.

The control device 2 makes this determination for the input operation from all the sensor devices 1. The buzzing of the indoor buzzer 4 and the outdoor buzzer 5 and the blinking of the display lamp 6 continue until the key switch 30 is turned off even if the failure is recovered.

FIG. 28 is a flow chart showing the flow of the receiver failure diagnosis operation by the controller in the embodiment of the present invention.

When the control device 2 cannot receive all the healthy signals transmitted at the cycle t1 from the sensor device 1 provided for each wheel, the control device 2 determines that the transmission / reception system has an abnormality, and determines the transmission / reception system. Record the failure. The target of this transmission / reception system failure includes the sensor device 1, the control device 2, the antenna 20, and the coaxial cable 21.

Next, the display lamp 6 is continuously turned on, and the indoor buzzer 4 and the outdoor buzzer 5 are sounded to warn the operator that there is a failure and to prompt the operator to take action. When the driver operates the alarm reset switch 29 in accordance with this failure alarm, the indicator lamp 6 continues to be lit, and the indoor buzzer 4 and the outdoor buzzer 5 stop sounding. Even if the trouble is taken and the normal state is restored, the alarm is continuously generated by turning on the display lamp until the key switch 30 is turned off.

[0096]

As described above, according to the present invention, it is possible to display on the driver's seat that electromagnetic waves from the sensor device of a specific tire cannot be received due to a failure of the sensor device mounted on the tire. It is possible to specify the sensor device in which the failure has occurred by a simple operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a sensor device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a main part of a control device according to an embodiment of the present invention.

FIG. 3 is a plan view of a vehicle chassis showing an overall configuration of a system according to an embodiment of the present invention.

FIG. 4 is a diagram showing a system configuration of a control device in the embodiment of the present invention.

FIG. 5 is a front view showing the outer shape of the sensor device according to the embodiment of the present invention.

FIG. 6 is a front view showing the internal structure of the sensor device according to the embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view taken along the line AA shown in FIG. 6 of the sensor device according to the embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view taken along line BB shown in FIG. 6 of the sensor device according to the embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view showing the structure of a manual switch incorporated in the sensor device according to the embodiment of the present invention.

FIG. 10A is a diagram showing a state in which a sensor device according to an embodiment of the present invention is mounted on a wheel, and FIG. 10B is a partially enlarged view of a sensor device portion.

FIG. 11 is a perspective view showing an operation surface of the momentary switch according to the embodiment of the present invention.

FIG. 12 is a diagram showing a configuration of a main part of an antenna on a control device side according to an embodiment of the present invention.

FIG. 13 is a diagram for explaining the shape and size of the control device according to the embodiment of the present invention.

FIG. 14 is a diagram showing a structure of a transmission / reception frame in the embodiment of the present invention.

FIG. 15 is a flowchart showing a flow of operation in a retained wheel storage mode by the control device in the embodiment of the present invention.

16 (a) to 16 (d) are views showing a display example of a total possessed wheel storage completion display in the embodiment of the present invention.

FIG. 17 is a diagram showing a configuration of a frame transmitted from the sensor device according to the embodiment of the present invention.

FIG. 18 is a diagram for explaining the configuration and transmission time of a healthy signal transmitted from the sensor device according to the embodiment of the present invention.

FIG. 19 is a diagram showing a frame structure of a block 5 of a healthy signal in the embodiment of the present invention.

FIG. 20 is a flowchart showing the flow of an identification code registration operation by the control device in the embodiment of the present invention.

FIG. 21 is a diagram showing a configuration of an alarm frame according to the embodiment of the present invention.

FIG. 22 is a diagram showing the configuration of a block 5 of an alarm frame according to the embodiment of the present invention.

FIG. 23 is a flowchart showing a flow of abnormal tire detection operation in the embodiment of the present invention.

FIG. 24 is a flowchart showing the flow of an alarm generation operation in the embodiment of the present invention.

FIG. 25 is a flowchart showing a flow of abnormal pneumatic tire specifying operation in the embodiment of the present invention.

FIG. 26 is a flowchart showing the flow of a sensor device failure determination operation by the control device in the embodiment of the present invention.

FIG. 27 is a flowchart showing the flow of a fault sensor identifying operation by the control device according to the embodiment of the present invention.

FIG. 28 is a flowchart showing the flow of a receiver failure diagnosis operation by the control device in the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 sensor device 2 control device 2a, 49 housing 3 alarm means 4 indoor buzzer 5 outdoor buzzer 5 indicator lamp 7 diagnostic monitor 8 vehicle speed sensor 10 microprocessor 11 pressure sensor 12 clock circuit 13 manual switch 13a push button 14 timer switch 15 E ² PROM or EEPROM 16 Modulator 17, 20 Antenna 18 Oscillator 19 Battery 21 Coaxial cable 22 Receiver 23 Digital analyzer 24 Momentary switch 24a Mode setting button 24b Wheel number setting button 25 Program control circuit 26 Memory 29 Alarm reset switch 30 key switch 31 tire 32 spare tire 33 case 34 tire valve 35 mounting nut 36 belt 37 bellows 38 contact 39 circuit board 40 conduction terminal 41 switch board 2 off switch 43 Rubber diaphragms 44 O-ring 45 spring 46 rubber caps 47 diagnostic switch 48 waterproof case

Claims (2)

(57) [Claims] 1. A sensor device mounted on a wheel for transmitting an electromagnetic wave modulated by a signal containing air pressure information of a tire mounted on the wheel, a receiver mounted on a vehicle and receiving the electromagnetic wave, and an output of the receiver. In a tire pressure warning device including a control device including a warning unit that outputs a warning according to the air pressure information obtained in step 1, the sensor device includes a pressure sensor that detects a tire pressure, and a trigger signal at a cycle t1. And a pulse train signal generation circuit that generates a frame pulse including an identification code (ID) and output information of the pressure sensor for a time t2 in accordance with the trigger signal. Means for registering the identification codes of all the sensor devices equipped in the device, and a period of n times the period t1 (n is an integer). Comprise means for sending an alarm sensor failure when one of the registered identification code means for the registration is not received over a tire pressure warning system according to claim. 2. The control device provides a means for judging a sensor failure and an audible alarm every time an audible alarm is continuously emitted and one of the identification codes registered in the registering means is received. The tire pressure warning device according to claim 1, further comprising: a means for temporarily suspending.