JPH1178446A - Tire inflation pressure warning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify a faulty sensor device with simple operation by registering identification codes of all sensor devices equipped at a vehicle, and giving a warning of a sensor failure when any one of the registered identification codes is not received for a period integer times as long as a specified cycle of trigger signals. SOLUTION: This tire inflation pressure warning device is provided with sensor devices 1 mounted on individual tires so as to transmit air pressure information, and a control device receiving and sending out an alarm. A pulse train signal generating circuit of the sensor device 1 generates and transmits frame pulse including an identification code and pressure information for specified time according to trigger signals generated in a specified cycle by a clocking circuit 12. In a control device receiving the frame pulse, when one of registered identification codes is not received for a period integer times as long as the specified cycle, the sensor device 1 is recorded as a failure, and a failure warning is given by a display lamp and an interior buzzer. The failure of the sensor device 1 can therefore be specified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention is applied to an automobile. The present invention relates to an improvement in a device that constantly detects tire pressure while a vehicle is running and issues an alarm when an abnormality occurs. The present invention relates to an apparatus for providing a sensor for detecting tire air pressure on a tire and transmitting air pressure information by a radio signal, that is, an electromagnetic wave, to a control apparatus installed in a vehicle. Although the present invention has been developed as a device suitable for a large vehicle having a large number of tires, the present invention can be applied to a device other than a large vehicle.

[0002]

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

There is also known a device in which a transmission circuit having a battery is individually provided in a tire and which generates a radio signal in accordance with tire pressure information (Japanese Patent Laid-Open No. 8-17878).
No. 4). This device prepares a detection device that is carried by the driver's hand, and receives a weak radio wave generated by a transmission circuit when the detection device is brought close to a tire.

Further, a technique is known in which a radio signal transmitted by a pressure sensor provided on a tire is shared with a radio signal generated by a radio key for door lock of an automobile (Japanese Patent Laid-Open No. 6-2).
No. 47114). In relation to this prior art, the reference publication discloses a technique in which the output of a tire pressure sensor is guided by a wire to a transmission device mounted on a wheel. In this technique, it is understood that the transmission device is provided with a power supply circuit using an individual battery.

[0005]

SUMMARY OF THE INVENTION The present inventor has studied a tire pressure warning device which can be applied to a large vehicle. The prior invention has an excellent feature that a battery circuit is simplified on the tire side since 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 prior application, the tire-side device receives an electromagnetic wave transmitted from the vehicle-side antenna, and uses the property of the resonance circuit provided in the tire-side device to resonate with the electromagnetic wave. The transmitted electromagnetic waves from the tire side are sometimes very weak. For this reason, in a vehicle with a small number of tires, for example, a passenger car, it is possible to dispose the antenna close to each tire, but in a large vehicle with a large number of tires, the number of antennas becomes large, and the vehicle side device Was found to be complicated.

[0006] In general, in some large vehicles, four or more tires are provided on one shaft, and in such a structure, even if the air pressure of one of them decreases, the driver recognizes it with a sense. This is difficult, and a vehicle having such a structure requires a tire pressure warning device.

On the other hand, the technique of providing a battery power supply to the tire-side device is a known technique as described above. However, the present invention has sought a configuration in which the battery is made as small as possible and does not require battery replacement. That is, it has been sought to shorten the time for transmitting electromagnetic waves as much as possible, minimize battery consumption, and extend the life of the vehicle to the tire life or more.

Further, when the number of tires in a large vehicle is as large as more than ten, even if a warning is given that the tire air pressure has dropped, the driver can recognize which tire it is. You need to do that. In general, it is conceivable to display the position of the tire on the driver's seat as a panel.However, such a decrease in the air pressure of the tire rarely occurs. The provision is not appropriate.

Further, the tires are installed when the vehicle is manufactured, but are replaced relatively frequently after the operation of the vehicle, and a complicated setting registration procedure is executed every time the tire is replaced. It is not appropriate to do so. Furthermore, when an electromagnetic wave is transmitted autonomously from a device provided on the tire and is received by a device provided on the vehicle body, the tire pressure is monitored. In such a case, electromagnetic waves from tires of other vehicles parked in the vicinity or other vehicles running close to each other should not be received, and the alarm should not be confused.

The present invention has been made in such a background, and an object of the present invention is to provide a tire pressure warning device applicable to a large vehicle having a large number of tires. SUMMARY OF THE INVENTION An object of the present invention is to provide a tire pressure warning device that can handle even when the number of tires becomes several tens.

An object of the present invention is to provide a device for displaying on a driver's seat that a failure has occurred in a sensor device mounted on a tire and electromagnetic waves cannot be received from a sensor device of a specific tire. An object of the present invention is 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 pressure of each of the tires mounted on a vehicle is detected at regular intervals during traveling, and the tire pressure information together with the tire identification code is transmitted to a control device by electromagnetic waves. When the control device cannot receive the electromagnetic wave, the sensor device determines that the sensor device has failed and displays a failure alarm on the driver's seat.

That is, the present invention provides a sensor device mounted on a wheel for transmitting an electromagnetic wave modulated by a signal including air pressure information of a tire mounted on the wheel, a receiver mounted on a vehicle and receiving the electromagnetic wave, A tire pressure alarm device including a control device including an alarm unit that sends an alarm in accordance with the air pressure information obtained from the output of the receiver; wherein the sensor device includes: a pressure sensor that detects a tire air pressure; 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 that generates a frame pulse including an identification code (ID) and output information of the pressure sensor, and registers in the control device identification codes of all sensor devices mounted on the vehicle. Means for sending an alarm for sensor failure when one of the identification codes registered in the registering means is not received for a period of n times (n is an integer) of the period t1. .

The control device includes means for judging a sensor failure, sounding an acoustic alarm continuously, and suspending the acoustic alarm 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 includes a spare device mounted on the vehicle.
Mounted on each and every tire, including tires.
In each of the sensor devices, the pressure sensor detects the tire pressure, and the pulse train signal generating circuit generates a frame pulse (ID) including an identification code and output information from the pressure sensor over a time t2 according to a trigger signal of a cycle t1 generated from a clock circuit. A healthy signal is generated, modulated, and transmitted as an electromagnetic wave.

The control device receives the healthy signal transmitted by the electromagnetic wave and registers identification codes of all the sensor devices mounted on the vehicle. If one of the registered identification codes is not received for a period of n times (for example, three times) the period t1, the sensor device is in a fault state and cannot transmit a healthy signal and issues a fault alarm to the driver's seat. Send it to the provided alarm means.

The transmission of the failure alarm is performed immediately when one of the registered identification codes is not received for a period of an integral multiple (for example, three times) of the period t1. When the driver operates the manual mode setting switch, for example, the mode setting button of the momentary switch a predetermined number of times (for example, five times) continuously by the occurrence of the failure alarm, the failure sensor specific mode is set. In this failure sensor identification mode,
The control device continuously emits an audible alarm, and when receiving one of the identification codes registered in advance by the healthy signal, the control device temporarily suspends the audible alarm and receives the identification code. That is, the driver is made aware that the sensor device is normal. When the push button of the failure sensor device is pressed, the audible alarm is continued.

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

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following modes are set in the control device of the tire pressure alarm device according to the present invention.

1) Retained wheel number storage mode 2) Initial setting mode 3) Abnormal tire detection mode 4) Alarm generation mode 5) Tire identification mode 6) Fault sensor identification mode The retained wheel number storage 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 when the registration is completed, the total number of wheels is displayed by sound.

The initial setting mode is set by operating the mode setting button for a predetermined time (for example, two seconds). In this initial setting mode, a signal transmitted when a manual switch of the sensor device is individually operated is received, and the identification code of the sensor device included in the signal is registered together with the wheel number of the vehicle. Each time the registration of this identification code is completed, the number of acoustic signals generated is the number indicating the wheel number. For example, for the first tire, one acoustic noise is produced, and for the fifth tire, five acoustic sounds are produced. As a result, the driver can reliably grasp the number of wheels whose identification code registration has been completed.

At the time of registration of the identification code, the manual switch of each sensor device is operated, and the timer switch for generating the built-in period t1 is reset in accordance with this operation. At t1, the operation time is the start time.

In the abnormal tire detection mode, a predetermined time (for example, 3) of a mode setting button indicating the completion of the initial setting of the identification code is set.
(Seconds). In this abnormal tire detection mode, the control device sends a cycle t1 from the sensor device.
A healthy signal transmitted every time is received, and it is determined whether or not the registered bit is “1”, that is, whether or not the tire pressure is normal. If "1" is indicated, the tire pressure is assumed to be normal and the tire pressure detection mode is continued.

The alarm generation mode is set when the registered bit of the healthy signal indicates "0" in the tire pressure detection mode, that is, when it is indicated that there is a wheel whose tire pressure is equal to or less than a predetermined value. . In this alarm generation mode, the identification of the identification code registered at the time of initial setting is performed, and an alarm indicating that there is an abnormal pneumatic tire is generated.

The tire specifying mode is set in response to the alarm. In this tire identification mode, in order for the driver to identify an abnormal tire when an alarm is generated, the manual switches of the sensor devices provided for each tire are sequentially operated, and the manual switch of the abnormal tire is pressed. Generates an audible alarm when Thereby, the driver can easily identify the abnormal tire.

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

As described above, the failure sensor identification mode is set when a manual mode setting switch, for example, a wheel number setting button of a momentary switch is continuously operated a predetermined number of times (for example, five times). In this failure 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 a push button of the corresponding sensor device is pressed.

When no signal arrives from any of the sensor devices, it is impossible that the arrival of signals from all of the sensor devices will not stop at the same time. Therefore, an alarm is issued as a failure on the receiving side.

[0029]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a main part of a sensor device according to an embodiment of the present invention, FIG. 2 is a block diagram illustrating a configuration of a main part of a control device according to the embodiment of the present invention, and FIG. FIG. 4 is a plan view of a vehicle chassis part showing the overall configuration of the vehicle, and FIG. 4 is a diagram showing a system configuration of a control device according to 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 mounted on a vehicle and transmitting the electromagnetic wave. There is provided a receiver for receiving and a control device 2 including an alarm means 3 for issuing an alarm in accordance with air pressure information obtained from an 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 pressure and outputs a detection output to the microprocessor 10, and a cycle t1 ( A clock circuit 12 that generates a trigger signal at 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, and an individual switch. E ² PROM or EEPROM storing the identification code of the tire 31 in advance
M15, a modulator 16 for modulating a pulse train signal sent from the microprocessor 10, and a modulator 16
An oscillator 18 that transmits the output of the antenna 17 as a radio signal from an antenna 17 and a battery 19 are provided.

The microprocessor 10 has a pulse train for generating a frame pulse including an identification code and output information of the pressure sensor 11 over a time t2 (≪t1, for example, 200 milliseconds) in accordance with a trigger signal generated by the clock circuit 12. Signal generation circuit and manual switch 13
Generates a frame pulse when is operated,
Means for resetting the switch 14.

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

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

The alarm means 3 shown in FIG. 2 includes an indoor buzzer 4 and an outdoor buzzer 5 for providing an acoustic display for other information including an alarm, and a lighting display and a blinking display for other information including an alarm. 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
In the state where the initial setting mode is set, a plurality of identification codes are determined from the electromagnetic waves received within the cycle t1 of the tire 3 of the vehicle.
1 means for recording as an identification code, means for registering the tire identification code of the vehicle for the number of tires set by the momentary switch 24, and means for generating an acoustic signal each time registration of the tire identification code is completed. Means for displaying the registered number of tires when the registration of the number of tires is completed.

As shown in FIG. 4, 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 are input to the control device 2, 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 diagnostic 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 diagnostic monitor 7.

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

The sensor device 1 is housed in a case 33, which is fixed to a tire valve 34. The tire valve 34 is connected to the tire 31 by a mounting nut 35. The pressure sensor 11 includes a bellows 37 that expands and contracts due to a change in air pressure, and the bellows 37.
A contact 38 fixed to the inner surface of the head of the vehicle and a conductive terminal 40 that contacts the contact 38 and sends an electric signal to the circuit board 39 when the air pressure is equal to or higher than a predetermined value. Placed in

The push button 13a of the manual switch 13 and the tire valve 34 are disposed so as to protrude 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.
The housing 49 and the switch board 4 housed in the housing 40
1, an open / close switch 42, a rubber diaphragm 43, an O-ring 44, a spring 45, and a rubber cap 46 that includes a housing 49 and transmits the pressing force to the rubber diaphragm 43 when the push button 13a is pressed. It consists of. The open / close switch 42 is a switch of a form in which the conductive rubber is in contact with the pattern of the switch substrate 41 when the rubber cap 46 is pressed, or a switch of a structure that is mechanically turned on when pressed. Used.

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

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

FIG. 12 is a diagram showing the configuration 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 line, and a connection portion with the coaxial cable 21 is covered by a waterproof case 48. As shown in FIG. 3, a plurality of the antennas 20 are arranged in a chassis portion of the vehicle.

FIG. 13 is a diagram for explaining the shape and size of the control device according to the embodiment of the present invention. The control device 2 shown in FIG. 2 is housed in the housing 2a, D = 120 mm,
It is formed in a size of 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 a configuration 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) to clarify the distinction from the other wheels. This identification code is composed of 25 bits.
No. 1 to No. 33, 554, 431 (= 2 ²⁵ −1). Therefore, when this number is exceeded, the No. Returning to 1, the same number is repeatedly assigned, but since the number of digits is extremely large, there is no practical duplication.

The frame used in this embodiment is shown in FIG.
Is divided into five blocks, a synchronization bit (10 bits), a start bit (2 bits), a first bit,
Second and third identification code (ID) code (7 bits each), fourth identification code (ID) code (4 bits), stop bit (1 bit), registration bit (1 bit),
The switch bit (1 bit) and the parity bit (1 bit)
), And the time required for transmission is 40 milliseconds per frame.

The synchronization bit is composed of a combination of "0" and "1", and is used to clarify where the start of the frame is at the time of transmission / reception. If the identification code (ID) code is “zero”, all bits from the first identification code (ID) code to the fourth identification code (ID) become “0”, so that the maximum “0” is 7 Continuous. Therefore, in order to recognize the beginning of the signal, at least "0"
Are required for eight consecutive identification bits. As shown in FIG. 14, the bits used in this embodiment are each composed of 10 bits, and the synchronous bits have a margin of 10 bits in which ten "0" s are arranged.

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

(A) in FIG. 14 is a start bit. In order to make it easy to recognize the beginning of the signal, it is arranged at the head of each block and is represented by "11". (B) is a stop bit indicating 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 is "0" at normal times. (D) is a switch bit, which is represented by "1" if the tire pressure is normal and "0" if the tire pressure is equal to or less than a predetermined value. (E) is a parity bit indicating a parity result of the identification code. By comparing the parity before the control device 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 configured as described above 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 responds to a trigger signal from the clock circuit 12 in accordance with the trigger signal.
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 the frame pulse, registers the identification code, and registers the period t1. (For example, 15
The purpose of the present invention is to send out a sensor device failure alarm when one of the registered identification codes is not received for a period of n times (n is an integer, for example, 3) times (minutes).

The sensor device 1 includes all the wheels 3 of the vehicle.
1 is individually equipped. Therefore, the control device 2 stores the number of wheels 31 held on the vehicle and stores an identification code corresponding to each wheel number.

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

When the control device 2 is started 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 determines the number of wheels of the vehicle ( Number of tires)
Is set, and the display lamp 6 flashes every 0.3 seconds to indicate that the stored wheel number storage mode has been set.

When the number-of-wheels 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 held wheels is input, the number of wheels input by this operation is reduced. The total number of wheels of the vehicle is stored in the memory 26. The total number of wheels held is set as one wheel by operating the wheel number setting button 24b once, and two wheels by operating the wheel number twice. For example, if the vehicle has 13 wheels, the mode setting button 24a is set to 1 after operating 13 times. By performing the operation twice, 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 input total number of wheels three times using the indoor buzzer 4, the outdoor buzzer 5, and the display lamp 6.
The display of the stored total number of wheels is shown in FIGS.
Is performed as shown in FIG. FIG. 2A shows one wheel, and FIG. 2B shows two wheels.
(C) shows a display example of six wheels, and (d) shows a display example of twelve wheels. For example, in the case of six wheels, as shown in FIG. 6C, a slightly longer sound and lighting indicating five wheels and a short sound and lighting indicating one wheel are repeated three times. In the case of 12 wheels, as shown in FIG. 4 (d), a slightly longer sound indicating five wheels is continuously performed twice, and then a short sound indicating one wheel and lighting are continuously performed twice. Repeat three times.

The display by the indoor buzzer 4, the outdoor buzzer 5, and the display lamp 6 allows 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 processing of the total number of retained wheels, it changes the lighting of the indoor buzzer 4, the outdoor buzzer 5, and the display lamp 6 to a one-second cycle, and sets an initial setting mode. .

Next, an operation of transmitting an 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 two seconds or more, the manual switch 13 is turned on, and a start signal is transmitted from the battery 19 to the microprocessor 10, the modulator 16 and the oscillator 18. The microprocessor 10 resets the timer switch 14 by the start signal.

[0062] Simultaneously, with taking the detected output of the pressure sensor 11, reads the identification code of the sensor device 1 which has previously been stored in the E ² PROM or EEPROM 15, the frame pulses comprising pressure information of the identification code and the tire 31 Is generated by the pulse train signal generation circuit, is modulated by the modulator 16 at the cycle t1 set by the timer switch 14, and is transmitted from the oscillator 18 as an electromagnetic wave via the antenna 17 over 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 in FIG. 5 shows an example in which the air pressure of the sensor device 1 is normal. As described above, the transmission frame at the time of the initial setting is transmitted with the registration bit indicated by oblique lines being “1”.

The frames configured as described above are transmitted as healthy signals in 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 runs out. Assuming that the transmission time for one frame is 40 milliseconds, the transmission time t2 for one transmission is 200 milliseconds for five frames. If the transmission cycle t1 is set to 15 minutes based on the results so far, the life of the battery 19 is longer than the life of the vehicle. Therefore, it is possible to use the vehicle 19 without replacing the battery 19 until the vehicle is disposed of. it can.

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

FIG. 19 is a diagram showing a 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 when the tire pressure is normal. The frame pulse at the time of the initial setting from the sensor device 1 is transmitted with the registration bit set to “0”. The control device 2 recognizes the frame pulse transmitted from the sensor device 1 by confirming the registration bit “0”.

Next, an operation of registering an identification code in the initial setting mode by the control device 2 will be described. FIG. 20 is a flowchart 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 operating the push button 13a of the sensor device 1, the control device 2 stores the first 50 bits of one frame in the memory 26. 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 determined to be normal and the transmitted identification code is registered in the memory 26. If the parity determination result is not correct, the reception of the frame pulse is repeated until the determination is correct, and is continued.

Each time the control device 2 registers the identification code,
A buzzer that indicates the number of the wheel is the indoor buzzer 4.
And from the outdoor buzzer 5. That is, if the number of wheels is the first, one blow sound is generated as shown in FIG. 16 (a), and if the number of wheels is the second, two blow sounds are generated as shown in FIG.
Generates a ringing sound. In the case of the sixth case, FIG.
A buzzing sound is generated in the form shown in FIG. Thus, the number of wheels for which registration of the identification code has been completed 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 receiving the operation input, the control device 2 compares the final number of wheels at the time of inputting the identification code with the total number of wheels stored at the time of inputting the number of held wheels, and if the number is the same, identifies all the wheels. It is determined that the registration of the code has been completed, the initial setting mode is released, the blinking of the display lamp 6 and the sounding of the indoor buzzer 4 and the outdoor buzzer 5 are stopped, and the abnormal tire detection mode is set.

If the registration of the recognition codes for all the wheels has not been completed, the blinking of the display lamp 6 is continued, and the sounds of the indoor buzzer 4 and the outdoor buzzer 5 are changed to, for example, "beep, beep,...". I do. When the push button 13a is operated again for two seconds or more due to this sound, the indoor buzzer 4 and the outdoor buzzer 5 are sounded in a cycle of one second as “P, P,...”, And registration of all the sensor devices 1 is performed. The same operation is repeated until the operation is completed.
When the key switch 30 is turned off, the control operation of the control device 2 is stopped.

As described above, when the initial setting including the storage of the number of held wheels and the identification code is performed by the sensor device 1 and the control device 2, the output of the identification code and the output of the pressure sensor 11 is performed at a constant period t1 (200 milliseconds). A frame pulse including information is continuously transmitted from the sensor device 1 as a healthy signal by electromagnetic waves.

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

The pressure sensor 11 provided in the sensor device 1
Is a threshold at which the air pressure of the tire 31 is set (for example,
When the pressure falls below 7.0 ± 0.5 kgf / cm ² ), the bellows 37 shown in FIG. 7 expands, and the contact which normally comes into contact with the conductive terminal 40 and is turned on is opened and turned off.

When the microprocessor (MPU) 10 receives the off signal, the microprocessor 2 (MPU) 10 reads the E ² PROM or EEPROM.
The identification code (ID) stored in M15 is read, and an alarm frame including the identification code is generated.
As shown in FIG. 21, this alarm frame is formed by 15 frames only for the first transmission so as not to be superimposed on the healthy signal transmitted from the sensor device 1 of another wheel. FIG. 22 shows only block 5 of one frame. If the tire air pressure is equal to or lower than the threshold value, the switch bit indicated by oblique lines is set to “0”.

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

FIG. 23 is a flowchart showing a flow of an abnormal tire detecting operation by the control device according to 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.

If the switch bit is "0", the electromagnetic wave is received when the sensor device 1 mounted on the tire enters a certain range on the circumference when the wheel is not rotating or when the vehicle is running 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 the speed exceeds 5 km / h, it is determined that the electromagnetic wave from the sensor device 1 has been reliably received, the vehicle speed flag is set, and the alarm generation mode is set.
Even if the vehicle speed falls below 5 km / h after the vehicle speed flag has been set, the alarm generation state is maintained while being set.

FIG. 24 is a flowchart showing a flow of an alarm generation operation by the control device according to 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,
The indoor buzzer 4 sounds and an alarm is generated to urge the user to take measures for the abnormal pneumatic tire. The driver can recognize from the warning that the tire pressure is abnormal. At this time, the control device 2 sets the tire identification mode.

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

When the control device 2 sets the tire identification 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. The control device 2 sequentially receives the confirmation operation signals and, when the push button 13a of the abnormally-pneumatic tire is operated, blows the outdoor buzzer 5 for one second to indicate that the tire is at an abnormal air-pressure. This allows the driver to specify the abnormal pneumatic tire.

When the tire identified as having 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 deleted by this overwriting, even if the transmission of the frame pulse from the sensor device 1 of the abnormal pneumatic tire is continued, it is not an object of control and no alarm is generated. After newly registering the identification code in this way, the control device 2 resets the vehicle speed flag, cancels the alarm generation mode, and sets the abnormal tire detection mode. Thereafter, a detection operation is performed by receiving a healthy signal.

Next, a sensor failure judging operation by the control device 2 which is a feature of the present invention will be described. FIG.
6 is a flowchart showing the flow of the sensor device failure determination operation by the control device according to the embodiment of the present invention.

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

When the driver resets the alarm reset switch 29 by recognizing the occurrence of a failure in the sensor device in accordance with the failure alarm, 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 continuously operated five times, the failure sensor identification mode is set. Set.

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

In this failure identification mode, the control circuit 2
The display lamp 6 flashes at 0.5-second intervals, and the indoor buzzer 4 and the outdoor buzzer 5 sound at 0.5-second intervals. Here, the driver operates the push button 13a for each sensor device 1 to confirm 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 the frame pulse has arrived, the display lamp 6 is turned off for 2 seconds and then flashes at 0.5-second intervals, and at the same time, the indoor buzzer 4 and the outdoor buzzer 5 stop sounding for 2 seconds and then 0.5 seconds. Sounds every second. By stopping for two seconds, the driver can confirm that the sensor device 1 is normal.

When the frame pulse has not arrived, the indicator lamp 6 continues to blink at 0.5 second intervals because the sensor device 1 is in the transmission disabled state or the ID code has been destroyed. The sounding of the indoor buzzer 4 and the outdoor buzzer 5 is continued as it is. Thus, the driver can specify that the sensor device 1 is out of order.

The control device 2 makes this determination for input operations from all the sensor devices 1. The sounding 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 after the failure is recovered.

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

The control device 2 determines that there is an abnormality in the transmission / reception system when a state in which all the healthy signals transmitted from the sensor device 1 provided for each wheel cannot be received at the cycle t1 occurs. Record the failure. The target of the 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 lit, and the indoor buzzer 4 and the outdoor buzzer 5 are sounded to warn of a failure state and to urge the user to take measures. When the driver operates the alarm reset switch 29 according to the failure alarm, the display lamp 6 continues to be lit, and the indoor buzzer 4 and the outdoor buzzer 5 stop sounding. Even if a measure is taken against the failure and the state returns to a normal state, the alarm generation by turning on the display lamp is continued until the key switch 30 is turned off.

[0096]

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

[Brief description of the 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 the embodiment of the present invention.

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

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

FIG. 5 is a front view showing the external 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.

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

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

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

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

FIG. 11 is a perspective view showing an operation surface of a 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 the control device side in the embodiment of the present invention.

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

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

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

FIGS. 16 (a) to (d) are views showing display examples of a display indicating completion of storage of the total number of held wheels 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 illustrating 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 healthy signal block 5 in the embodiment of the present invention.

FIG. 20 is a flowchart showing a 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 a configuration of an alarm frame block 5 in the embodiment of the present invention.

FIG. 23 is a flowchart showing a flow of an 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 an 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 according to the embodiment of the present invention.

FIG. 27 is a flowchart showing a flow of a fault sensor specifying 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 according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sensor apparatus 2 Control apparatus 2a, 49 Case 3 Alarm means 4 Indoor buzzer 5 Outdoor buzzer 6 Indicator lamp 7 Diag 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 speed setting button 25 program control circuit 26 memory 29 alarm reset switch Reference Signs List 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 Conductive terminal 41 Switch board 42 Open / close switch 43 Rubber diaphragm 44 O-ring 45 Spring 46 Rubber cap 47 Diag switch 48 Waterproof case

Claims (3)

[Claims] 1. A sensor device mounted on a wheel for transmitting an electromagnetic wave modulated by a signal including air pressure information of a tire mounted on the wheel, a receiver mounted on a vehicle for receiving the electromagnetic wave, and an output of the receiver. A tire pressure alarm device including a control device that includes an alarm unit that sends an alarm in accordance with the air pressure information obtained in the above. And a pulse train signal generating circuit that generates a frame pulse including an identification code (ID) and output information of the pressure sensor over a time t2 according to the trigger signal. Means for registering the identification codes of all the sensor devices provided in the device, and a period of n times (n is an integer) of the period t1. 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 according to claim 1, further comprising: means for judging a sensor failure; sounding an audible alarm continuously; and outputting an audible alarm each time one of the identification codes registered in the registering means is received. Means for temporarily suspending
The tire pressure warning device as described in the above. 3. The tire pressure warning device according to claim 2, wherein the sensor device includes a manual switch, and means for transmitting the trigger signal when the manual switch is operated.