Pressure Measuring Device

Abstract

This utility model is a specialized instrument for measuring tire pressure and other inflatable products and can be used as part of a test rig for aircraft tires. The technical objective of the utility model, consistent with the positive results of its application, is to improve the accuracy of tire pressure measurements for vehicles. The device consists of a rotating and a stationary part. The rotating part is mounted on the rotating assembly sleeve and includes a strain gauge pressure transducer that measures the nitrogen pressure in a tubeless tire. The strain gauges are connected in a full-bridge configuration.The positive terminal of the rotating secondary winding of the transformer is connected to the converter input via a series-connected filter consisting of a diode and inductor connected in parallel, and a voltage stabilizer. The pressure converter output is connected via an operational amplifier to the frequency converter, whose output, via a filter made in the form of a capacitor, is connected to the positive terminal of the secondary winding of the rotating transformer. The negative terminal of the secondary winding is pulled to ground. The stationary section includes the primary stationary winding of the transformer, secured to the axis of the rotating assembly hub. The positive terminal of the winding is connected to the measuring input of the control unit and to the power output, and the negative terminal of the primary transformer winding is pulled to ground.The control unit is based on a microcontroller, and the measuring input of the control unit is based on an operational amplifier connected to the analog-to-digital converter line of the microcontroller. 4 pp. f-ly, 1 fig.

Description

[0001] The utility model relates to specialized devices for measuring pressure in tires and other inflatable products and can be used as part of a test bench for testing aircraft tires for compliance with the qualification requirements for aircraft tires, regulated by the regulatory document KT 32-02.

[0002] A device for monitoring the pressure in automobile tires is known from the prior art, comprising pressure drop sensors and an electrical circuit for polling them (RU 2160437 C2, IPC G01L 9 / 00, G01L 17 / 00, published 10.12.2000). The sensors are configured to respond to the difference in pressure in the tires, one of the front axle, the other of the rear axle, wherein the base of each sensor is a flexible tube made of insulating material, bent so that it has vertical parts, each connected to one of the tires of the axle, filled with a non-freezing conductive liquid with three electrodes mounted, two of which are located in the vertical parts of the tube at the level of the liquid surface, determining the permissible pressure drop in the tire of the automobile.

[0003] The disadvantage of the known technical solution is the limited possibility of adapting the device for measuring the pressure of a gaseous medium in aircraft tires.

[0004] The closest technical solution to the claimed utility model and selected as a prototype is a portable threshold electronic pressure gauge for measuring the pressure in a pneumatic tire of a vehicle (RU 2216002 C2, IPC G01L 17 / 00, B60C 23 / 00, published 10.11.2003). The device comprises a pressure indicator connected to a microcontroller, an analog-to-digital converter, the output of which is connected to the microcontroller, and the input to the pressure sensor, a power source with a device shutdown control system connected to an activation button and to the aforementioned units of the device.

[0005] A drawback of the device is its low technological level, due to the large number of discrete elements in its design, which complicates its electrical circuit. For example, using a separate real-time chip seems unnecessary, as all modern microcontrollers contain built-in timers / counters that ensure precise time interval counting.

[0006] The technical problem that the claimed utility model is aimed at solving is to increase the accuracy of measuring the pressure in vehicle tires, primarily in aircraft tires, with the ability to save the recorded measurement results and transmit them to a remote vehicle condition monitoring system.

[0007] This problem is solved by a device for measuring aircraft tire pressure consisting of a rotating and a stationary part. The rotating part is mounted on the rotating assembly sleeve and includes a strain gauge pressure transducer, which measures the nitrogen pressure in the tubeless tire. The strain gauges of the transducer are connected in a full-bridge circuit. The positive terminal of the rotating secondary winding of the transformer is connected to the transducer input via a series-connected filter made of a diode and inductor connected in parallel, and a voltage stabilizer. The output of the pressure transducer is connected via an operational amplifier to a frequency converter, the output of which is connected via a filter made in the form of a capacitor to the positive terminal of the secondary winding of the transformer, with the negative terminal of the secondary winding pulled to ground.The stationary section comprises a primary fixed transformer winding, secured to the rotation unit's hub axis. The positive terminal of the winding is connected to the control unit's measuring input and the power output, while the negative terminal of the primary transformer winding is pulled to ground. The control unit is based on a microcontroller, and the control unit's measuring input is based on an operational amplifier connected to the microcontroller's analog-to-digital converter (ADC) line.

[0008] A positive technical result provided by the combination of features of the device is an increase in the accuracy of measuring the pressure in an aircraft tire due to the use of a control unit in the device, based on a microcontroller

[0009] The utility model is illustrated by a drawing, where Fig. 1 shows a fragment of the electrical circuit diagram of the device.

[0010] The device for measuring pressure, preferably in an aircraft tire, has the following structure.

[0011] The device consists of a rotating and a stationary part, wherein the rotating part is mounted on the bushing of the tire rotation unit (wheel shell) and includes a strain gauge pressure transducer 1, which measures the nitrogen pressure in a tubeless tire, the strain gauges 2 of which are connected in a full-bridge circuit. The positive terminal of the rotating secondary winding of the transformer 5 is connected to the input of the transducer through a series-connected filter 3, made of a diode and inductor connected in parallel, and a voltage stabilizer 4; the output of the pressure transducer 1 is connected through an operational amplifier 6 to a frequency converter 7, the output of which, through a filter made in the form of a capacitor 8, is connected to the positive terminal of the secondary winding of the transformer 5, while the negative terminal of the secondary winding of the transformer is pulled to the ground.The stationary section comprises the primary fixed winding of transformer 5, secured to the axis of the rotating assembly hub. The positive terminal of the transformer winding is connected to the measuring input of the control unit (not shown in the figures) and to the power output, which is based on a composite transistor representing a Darlington pair. The negative terminal of the transformer primary winding is pulled to ground. The control unit is based on a microcontroller, which can be a domestically produced 1887BE7T microcircuit, and the measuring input of the control unit is based on an operational amplifier connected to the first line of the microcontroller's analog-to-digital converter.

[0012] The microcontroller includes a microprocessor core containing program FLASH memory, the output of which is connected via a decoder to general-purpose registers connected to the arithmetic logic unit, to which the static random-access memory (SRAM) of the data is connected. The microprocessor core is connected via a system bus to the peripheral devices of the microcontroller, which include a general-purpose input / output interface grouped into universal bidirectional eight-bit GPIO input / output ports, a universal synchronous-asynchronous receiver / transmitter (USART), timers / counters, a pulse-width modulator (PWM), and an eight-channel ten-bit analog-to-digital converter (ADC).In this case, the first GPIO input / output port is connected to the power output of the device, the second and third GPIO input / output ports are connected, respectively, to a text LCD indicator and a push-button keyboard consisting of sixteen keys, which are intended for testing and calibrating the device, the first line of the analog-to-digital converter, as mentioned above, is connected to the measuring input of the device, and a radio module is connected to the universal synchronous-asynchronous transceiver, which ensures the transmission of telemetry information to a remote tire pressure monitoring system.

[0013] The pressure measuring device works as follows.

[0014] Initially, the rotating part of the device is mounted on the tire rotation unit hub, the stationary part is secured to the rotation unit hub axis, and the device control unit housing is secured to the body of the measuring rig or vehicle. If the device is used in an aircraft, the control unit is installed in the cockpit. After completing the above installation steps, the positive terminal of the transformer's primary winding is connected to the device control unit's measurement input and its power output, and the text LCD indicator and keypad are connected to the second and third GPIO ports of the microcontroller to configure the device's operating parameters, specifically to establish a wireless communication channel with a remote tire pressure monitoring system. After completing the necessary settings, the device is activated.

[0015] During the entire measurement period, the microprocessor core of the microcontroller, based on the control program stored in the program FLASH memory, generates a sinusoidal signal and, in the case of using the 1887BE7T microcontroller control unit as the basis, uses the PB5 (OC1A) line of port B, operating in the alternative function mode - the pulse-width modulator output, through the power output, supplies power to the pressure transducer 1 with an alternating current of approximately 3200 Hz through a transformer. After power is supplied to the converter, the microprocessor core of the microcontroller reads the tire pressure value measured through the measuring input of the analog-to-digital converter, buffers the data in the SRAM data memory and transmits it to the remote tire pressure monitoring system.

[0016] Each measurement cycle lasts 150 ms; the circuit is powered for 15 ms, and pressure measurements are performed over five cycles, each lasting 2 ms. As a result, pressure transducer 1 of the device converts the measured pressure range from 0 to 300 psi (0 ÷ 20.4 atm) into a current frequency in the range of 50 to 100 kHz.

[0017] Thus, the device considered in this application is a high-tech device that can be useful both in conducting certification, periodic and technological tests of tires for compliance with qualification requirements, and in scientific research tests, for example, in the experimental study of the characteristics of aircraft tires, including their reliability, strength and time between failures.

Claims

1. A device for measuring the pressure in aircraft tires, comprising a fixed part, characterized in that the fixed part includes a primary fixed winding of a transformer secured to the axis of the sleeve of the rotation unit, wherein the positive terminal of the winding is connected to the measuring input of the control unit and to the power output, and the negative terminal of the primary winding of the transformer is pulled to the "ground", wherein the control unit is implemented on the basis of a microcontroller, and the measuring input of the control unit is implemented on the basis of an operational amplifier connected to the line of the analog-to-digital converter of the microcontroller, including a microprocessor core containing FLASH program memory, the output of which is connected through a decoder to general-purpose registers connected to an arithmetic logic unit, to which operational static SRAM data memory is connected;The microprocessor core is connected via a system bus to the peripheral devices of the microcontroller, which include a general-purpose input / output interface grouped into universal bidirectional eight-bit GPIO input / output ports and an analog-to-digital converter; the measuring input of the control unit is connected to the line of the analog-to-digital converter of the microcontroller, and its first GPIO input / output port is connected to the power output of the device.

2. A device for measuring pressure according to paragraph 1, characterized in that the power output is made on the basis of a composite transistor, which is a Darlington pair.

3. The device according to paragraph 1, characterized in that the microprocessor core is connected via a system bus to the peripheral devices of the microcontroller, which include a universal synchronous-asynchronous transceiver, timers / counters, and a pulse-width modulator.

4. A pressure measuring device according to paragraph 1, characterized in that a text LCD indicator and a push-button keyboard consisting of sixteen keys are connected to the second and third GPIO input / output ports, respectively.

5. The device according to paragraph 1, characterized in that the microcontroller of the control unit is a microcontroller of the 1887BE7T model.

Images