CN1297417C - Tyre pressure monitoring system of vehicle - Google Patents

Abstract

The present invention relates to an automobile tyre pressure monitoring system comprising a tyre pressure receiving display and a tyre pressure sensing transmitter, wherein the signals between the tyre pressure receiving display and the tyre pressure sensing transmitter are connected with each other in a wireless transmission mode; the tyre pressure receiving display comprises a radio frequency receiving circuit, a microcontroller circuit, a display circuit, a power supply, a status setting key, a tyre pressure display window, a tyre status indicator lamp and a buzzer; the radio frequency receiving circuit, the microcontroller circuit, the display circuit and the power supply are arranged in a box body, and the status setting key, the tyre pressure display window, the tyre status indicator lamp and the buzzer are arranged on a panel of the box body; and the tyre pressure sensing transmitter comprises a battery arranged under the circuit board, a sensor circuit arranged on the circuit board, a microcontroller circuit and a radio frequency transmitting circuit. The present invention is characterized in that a rubber container is arranged on the circuit board, and an enclosed cavity body filled with liquid forms between the rubber container and circuit board. The present invention solves the technical problem of difficulty in real time monitoring of the tyre pressure of medium-size and large coaches and trucks. The present invention has the advantages of less error in pressure transmission, safety, reliability, and convenient installation and replacement.

Description

Automotive Tire Pressure Monitoring System

Technical field

The invention relates to a vehicle safety monitoring facility, in particular to an inner tube type vehicle tire pressure monitoring system.

Background technique

Insufficient tire pressure during the running of the car will lead to serious tire wear, increased fuel consumption, difficulty in handling and control, and even tire burst, resulting in car crashes and fatal accidents. In order to enhance the safety of the car during driving, it is necessary to monitor the pressure of the car tires in real time, remind the driver to pay attention to the change of tire pressure in time, and take corresponding measures. The original automobile tire pressure monitoring system TPMS (Tire Pressre Meare System) is used to monitor the pressure change of the tubeless tire, but the tubeless tire has little bearing capacity and can only be used for cars or light vehicles. Because large, medium-sized and above passenger and trucks are equipped with inner-tube tires with large load-bearing capacity, the original automobile tire pressure monitoring system TPMS cannot monitor the tire pressure of medium, large and above high-speed passenger and trucks in real time. . For example, the 6th issue of "China Electronics News" issued on December 2, 1999 reported "a kind of automobile tire pressure monitoring system" launched by the German Mercedes-Benz Motor Company. The system is composed of tire pressure sensors, high-frequency detectors and control devices composed of. When the pressure of any tire on the car is lower than the specified standard value, the warning light installed on the dashboard of the car will send an alarm signal to the driver, and the monitoring of the tire pressure is accurate and reliable. But the system does not respond to pressure changes caused by temperature changes, so the effect of hot air on the tires does not cause an alarm. To prevent false alarms, two pressure sensors are installed on each tire. The name disclosed in CN1479678 is "Automotive Tire Inflation Pressure Monitoring Equipment and Method", and its monitoring equipment includes: a device for determining the vehicle wheel speed or other parameters that characterize the vehicle wheel speed, a calculation device for the difference between the wheel speed or wheel speed parameters, A device that evaluates these differences with a setpoint value error and generates an alarm signal when the setpoint value error exceeds a threshold value. In addition, the monitoring device also includes a device for directly measuring the inflation pressure in the tire and transmitting a parameter characterizing the inflation pressure to the analysis device, when the error of the parameter characterizing the inflation pressure from a set value exceeds a corresponding When the threshold value is exceeded, the analysis device generates an alarm signal. The title of CN2092452 announcement is called the patent of " car tire low pressure alarm ", and the car tire low pressure alarm of this patent is to open a small mouth on the rim of the car, and install the sleeve type sensor on it, and install it on the brake disc. linkage switch. When the tire pressure of the car drops to a certain value, the dimension rod of the sleeve sensor is pushed out, drives the linkage switch, and connects the circuit of the buzzer to realize a timely alarm. The title of CN2108338 announcement is called the patent of " automobile tire air pressure reporting device ", and this device is made up of pressure gauge, valve connector, ultrasonic transmitter and receiver etc. Install the pressure pointer and the limit pressure adjustment pointer in the pressure gauge. The two pointers are not in contact with each other and are respectively connected to wire a or wire b. The other end of wire a is connected to the power supply, and the other end of wire b is connected to the ultrasonic transmitter. The ultrasonic transmitter is connected to Wire c and connect to the power supply, install the pressure gauge, battery (power supply) and ultrasonic transmitter in a fixed box, the fixed box is installed on the wheel half shaft, the pressure gauge is connected to the pressure air pipe, and the other end of the air pipe is connected to the air nozzle connected to the tire valve. The tire pressure sensor transmitter of the tubeless tire pressure monitoring system is placed in the tire air, and there is no pressure reading error caused by the non-sensor chip; Can best launch. Although the tire pressure sensor transmitter with the inner tube tire pressure monitoring system can also be placed in the tire, the design requirements for the circuit are high, and each tire pressure sensor transmitter must be installed in the corresponding tire and cannot be interchanged. Therefore, it is inconvenient to install and replace. Also have the tire pressure sensing transmitter to be installed at the valve core place of inner tuber, though easy to install and replace, come off easily and lose, and safety is poor.

Contents of Invention

The purpose of the present invention is to provide a kind of automobile tire pressure monitoring system, it can detect and display the pressure of inner tube type automobile tire in real time, when tire overpressure and underpressure, use acousto-optic mode to remind driver to pay attention to tire pressure situation, prevent A tire blowout occurs; when the tire pressure is normal, it can also improve the operating efficiency of the car and reduce fuel consumption.

The automobile tire pressure monitoring system of the present invention comprises the tire pressure receiving display installed in the cab and more than one tire pressure sensing transmitter installed on the automobile tire; between the tire pressure receiving display and the tire pressure sensing transmitter The signal connection is wireless transmission mode; only one tire pressure receiving display is installed in each car, its function is to receive the tire pressure signal emitted by the tire pressure sensor transmitter, display the tire pressure data after processing, and judge whether the tire pressure is normal, If the pressure is under or over pressure, the driver will be reminded by sound and light; one tire pressure sensor transmitter is installed for each tire, and its function is to transmit the pressure data measured by the pressure sensor to the tire pressure receiving display by radio transmission.

The tire pressure receiving display includes a radio frequency receiving circuit, a microcontroller circuit, a display circuit and a power supply arranged in the box body, a state setting key, a tire pressure display window, a tire status indicator light and a buzzer arranged on the box body panel. The RF receiving circuit consists of RF receiving integrated block IC1, antenna filter network C12, C14, L2, low-noise antenna RF amplifier, grounded parallel resonant network L1, C13, bypass capacitors C3, C1, data high-pass filter cut-off frequency capacitor C7, phase-locked Ring reference frequency crystal X1 and matching capacitor C15, phase-locked loop comparator output pulse low-pass filter network R1, C8, C9, low-pass filter power supply bypass capacitor C2, data demodulation power supply bypass capacitor C4, its function is to be composed of The ASK radio frequency signal from the antenna passes through the antenna filter network to the low-noise amplifier LNA inside IC1, and the local oscillator frequency generated by the internal VCO is mixed internally to generate an intermediate frequency signal. The data terminal DATA is output to the integrated block of the microcontroller. Microcontroller circuit consists of IC2, crystal X2, crystal matching capacitors C16, C17, reset network R4, C5, setting circuit SW1, R3, buzzer circuit B1, R5; the function of IC2 is to decode and identify the data from IC1 The pressure data generated by processing is sent to the display circuit, and when the pressure data is abnormal, IC2 generates an alarm signal and sends the buzzer to generate an alarm sound; the function of crystal X2 is to generate the capacitor clock required by IC2; the function of the reset circuit is to generate the upper Electrically delayed low-level reset signal; the function of the setting circuit is to set different states of the microcontroller integrated block IC2. The display circuit consists of a double-digit display digital tube N1, a decimal point field current-limiting resistor R10, a display gate line control circuit Q1, Q2, Q3, resistors R6, R7, R8, tire display light-emitting diodes D1, D2, D3, D4, D5, D6, D7, composed of current limiting resistors R9, R11, R12, R13, R14, R15, R16 in the display field; the function of the double-digit display digital tube N1 is to display pressure data, and Q1 and R6 are strobe control N1 high-digit digital tubes, Q2 and R7 are strobe control N1 low digital tubes, Q3 and R8 are strobe control tire display LEDs. The power supply is composed of ZN1, V2, V4, RZ, R2, C10, and C11, of which ZN1 is externally connected to the car battery, and provides the voltage of the car battery to the voltage regulators V2 and V4; R2, RZ are protection resistors, C10, and C11 are filter capacitors .

The tire pressure sensing transmitter includes a battery located under the circuit board, a sensor circuit located on the circuit board, a microcontroller circuit and a radio frequency transmitter circuit, and a rubber bag is arranged on the circuit board, and the edge of the rubber bag and the circuit The edge of the board is closely attached and stuck in the package crimping metal frame, and the closed cavity formed between the rubber bag and the circuit board is filled with liquid; except for the upper part of the rubber bag, the rest of the above components are sealed with packaging materials. Inside the rubber jacket. The sensor circuit is composed of the sensor integrated block U1 and the pull-up resistor R1. Its function is to output the pressure data obtained by the sensor integrated block U1 window to the microcontroller through amplified sampling processing; U1 sends it to the microcontroller integrated block U2 at regular intervals. Interrupt signal, reset signal and output pressure and other data; and receive the strobe signal, clock signal and command signal from the microcontroller integrated block U2; the role of the pull-up resistor R1 is to maintain a high level when U1 is output data. The microcontroller circuit is composed of microcontroller integrated block U2, crystal X1, and crystal matching capacitors C2 and C3; among them, the microcontroller integrated block U2 works and receives the pressure data from U1, which is processed by the microcontroller integrated block U2. Output to the RF transmitter; U2 receives the interrupt signal and reset signal from U1; the I/O port of U2 generates the gate line NCS, data output line SDO, clock line CLK, and data input line SDI required by U1; the role of crystal X1 It is to generate the clock signal of the microcontroller; the function of C2 and C3 is to match the crystal oscillator to generate precise oscillation frequency. The radio frequency transmitting circuit is composed of transmitting transistor Q1, transmitting antenna A1, capacitors C1, C4, C5, C6, resistor R3 and crystal X2; the role of transmitting transistor Q1 is to generate radio frequency oscillating signals and amplify and transmit them; the role of transmitting antenna A1 is to effectively Transmit radio frequency signal, and serve as the inductance part of the radio frequency oscillation circuit; Capacitors C1 and C4 are radio frequency oscillation capacitors; C6 is the output coupling capacitor; C5 is the radio frequency oscillation AC bypass capacitor; the function of resistor R3 is to provide radio frequency oscillation amplification bias current; When the data signal of the controller U2 is high level, the radio frequency oscillator amplifies and works, and when it is low level, the radio frequency oscillator does not work, thereby generating an ASK radio frequency signal and transmitting it through the transmitting antenna.

In the automobile tire pressure monitoring system, the tire pressure sensing transmitter is installed between the inner tube of the automobile tire and the tire pad, and the upper part of the rubber bag is in close contact with the inner tube. In this way, the force F per unit area on the inner tube of the automobile tire can be easily obtained, that is, the pressure P. The pressure P obtained by the rubber bag is transmitted to the pressure sensing chip of the sensor circuit through the pressure transmission medium, so that the circuit board can obtain the pressure data, and after the amplification, sampling and processing, it is transmitted through the transmitting antenna of the radio frequency transmitting circuit, and the tire installed in the cab The pressure receiving display can receive the signal from the tire pressure sensor transmitter.

In the automobile tire pressure monitoring system, the liquid filled in the closed cavity formed between the rubber bag of the tire pressure sensing transmitter and the circuit board is silicone oil or liquid grease. The best effect is to use liquid as the pressure transmission medium to transmit the pressure to the sensor.

The invention solves the technical problem that the original automobile tire pressure monitoring system TPMS cannot monitor the pressure of the tires of medium and large passenger trucks running at high speed in real time. It not only has small pressure transmission error, is safe and reliable, but also is easy to install and replace.

Description of drawings

Fig. 1 is a schematic diagram of the use state of the present invention.

Fig. 2 is a structural schematic diagram of a tire pressure sensing transmitter.

Figure 3 is a circuit diagram of the tire pressure receiving display.

Figure 4 is a circuit diagram of the tire pressure sensing transmitter.

Detailed ways

1 and 2, the box body 10 is provided with a radio frequency receiving circuit 11, a microcontroller circuit 12, a display circuit 13 and a power supply 14, and the box body 10 panel is provided with a state setting key 15, a tire pressure display window 16, The tire pressure receiving display 1 of tire state indicator lamp 17 and buzzer 18 is installed in the automobile cab, and power supply 14 is connected with automobile storage battery; Above, the battery 21 is installed under the circuit board 20, and the rubber bag 25 is buckled on the top of the circuit board 20, so that the edge of the rubber bag 25 is closely attached to the edge of the circuit board 20, and is stuck in the package crimping metal frame 26, Silicone oil 27 is filled in the closed cavity formed between the rubber bag 25 and the circuit board 20, and then, with encapsulating material—epoxy resin 28, the remaining parts except the top of the rubber bag 25 are sealed in the rubber jacket 29, namely Constitute tire pressure sensing transmitter 2. The tire pressure sensing transmitter 2 is installed between the inner tube of the automobile tire and the tire pad, and each tire is equipped with a tire pressure sensing transmitter 2, and the top of the rubber bag 25 is closely contacted with the inner tube.

When in use, first turn on the power supply of the car, and the buzzer 18 of the tire pressure receiving display 1 will make a short beep, indicating that the tire pressure monitoring system of the car starts to work. After one beep, it will beep continuously for 15S. At the same time, the tire status indicator 17 indicating the tire position will flicker. When the pressure is lower than the normal pressure, the flickering speed is slow, about 2S once, and when the pressure is higher than the normal pressure, the flickering speed is faster, about 1S. , to remind the driver that some tires are not within the normal pressure range. If there is a big difference between the tire pressure and the normal pressure, the buzzer 18 will always sound, and the tire status indicator light 17 will flash non-stop, reminding the driver that the tire must be inflated or deflated. When the tire pressure was normal, the tire status indicator light 17 representing the tire position would not flicker, and the always bright tire status indicator light represented that the number displayed by the LED nixie tube was the pressure data of the tire at this position.

When the tire pressure needs to be displayed cyclically, the status setting key 15 of the tire pressure receiving display 1 can be pressed, and the tire status indicator light 17 will press the left front wheel→right front wheel→right rear wheel→left rear wheel→(right rear inner wheel→ Left rear inner wheel →) left front wheel shines in turn, every time you press it, the position where the tire status indicator light 17 is lit changes once, and the numerical value of the LED nixie tube indicates the tire pressure at the position where the tire status indicator light 17 is lighted. When the tire pressure is displayed cyclically, if the tire pressure at this position is abnormal, the tire status indicator light 17 will always be on for 5 seconds, and then flash.

If the tire pressure sensing transmitter 2 installed on the tire is damaged and no signal is received in two hours, the tire status indicator light 17 at the corresponding position will also flash all the time, and the buzzer 18 will stop after buzzing for 15 seconds. When the position tire pressure is displayed by the state setting key 15, the tire pressure display window 16 will display the symbol "nP".

Claims (3)

1. Automobile tire pressure monitoring system, including the tire pressure receiving display (1) installed in the cab and more than one tire pressure sensing transmitter (2) installed on the automobile tire; the tire pressure receiving display (1) and the tire pressure The signal connection between the sensing transmitters (2) is a wireless transmission mode; the tire pressure receiving display (1) includes a radio frequency receiving circuit (11), a microcontroller circuit (12), a display Circuit (13) and power supply (14), the state setting key (15) that is located on the box body (10) panel, tire pressure display window (16), tire state indicator light (17) and buzzer (18); The tire pressure sensing transmitter (2) comprises a battery (21) located under the circuit board (20), a sensor circuit (22) located on the circuit board, a microcontroller circuit (23) and a radio frequency transmitting circuit (24) , which is characterized in that a rubber bag (25) is arranged on the circuit board (20), and the edge of the rubber bag (25) is in close contact with the edge of the circuit board (20), and is stuck in the package crimping metal frame (26), The closed cavity formed between the rubber bag (25) and the circuit board (20) is filled with liquid (27); except the top of the rubber bag (25), all the other components are sealed with packaging material (28). Inside the rubber jacket (29). 2. The automobile tire pressure monitoring system according to claim 1, characterized in that the tire pressure sensing transmitter (2) is installed between the inner tube and the tire pad of the automobile tire, and the upper part of the rubber bag (25) is in close contact with the inner tube . 3. The automobile tire pressure monitoring system according to claim 1, characterized in that it is filled in the closed cavity formed between the rubber bag (25) of the tire pressure sensing transmitter (2) and the circuit board (20). Liquid (27) is silicone oil.

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