CN218566760U - A high-performance piezoresistive pressure sensor - Google Patents

Abstract

The utility model provides a high-performance piezoresistive pressure sensor, which comprises a filler neck, a shell and a plug which are connected in sequence; the pressure-sensing pipe is characterized in that a core body pressure-sensing cavity and a pressure-sensing core body are arranged in the filler pipe nozzle, and the pressure-sensing core body is arranged in the core body pressure-sensing cavity; a first filter plate, a signal conditioning plate and a second filter plate are arranged in the shell; the first filter board is electrically connected with a pin of the pressure sensing core body, the signal conditioning board is connected with the second filter board through a pin connector, and the second filter board is connected with the plug through a wire. The utility model filters the voltage signal output by the pressure sensing core body through the first filtering plate, amplifies the filtered voltage signal through the signal conditioning plate and compensates the temperature, thereby improving the output precision of the sensor; carry out the filtering through the power that sets up second filtering board docking plug input, prevent that power signal from producing the interference to the normal work of sensor, further promoted the output accuracy and the long-term stability of sensor.

Description

A high-performance piezoresistive pressure sensor

technical field

The utility model relates to the technical field of sensors, in particular to a high-performance piezoresistive pressure sensor.

Background technique

Piezoresistive pressure sensors are widely used in military and aerospace fields, and many applications have strict requirements on the reliability and temperature error of the sensor. For example, in pipeline pressure measurement applications, once the sensor fails and the measured gas or liquid leaks, not only will the measurement task fail, but in severe cases it will even cause casualties. Compared with other similar sensors, the piezoresistive sensor has no general mechanical transmission structure, so it completely eliminates the friction error, and can also eliminate the error caused by the creep and hysteresis of the metal diaphragm in the general sensor, greatly improving the accuracy of the sensor, and It has good shock resistance, corrosion resistance, anti-interference ability, stability and reliability, and is widely used in aerospace, aviation, navigation and other fields.

The error of piezoresistive pressure sensor mainly comes from the influence of ambient temperature and electromagnetic interference. The error caused by temperature influence is generally eliminated by temperature compensation technology. The error of electromagnetic interference is generally eliminated by electromagnetic shielding technology, and electromagnetic shielding Technology can only shield the interference of the external signal of the sensor, and the interference of the internal signal of the sensor cannot be effectively eliminated, resulting in low sensor accuracy; with the development of the national economy, the accuracy of piezoresistive pressure sensors in fields such as aerospace, weaponry, etc. Higher and higher requirements are put forward for reliability and reliability, and the accuracy of traditional piezoresistive pressure sensors can no longer meet the requirements.

Contents of the invention

The utility model proposes a high-performance piezoresistive pressure sensor, which solves the problem in the prior art that the piezoresistive pressure sensor only eliminates signal interference through electromagnetic shielding, resulting in low detection accuracy.

The technical scheme of the utility model is achieved in that:

A high-performance piezoresistive pressure sensor, including a nozzle connected in sequence, a housing and a plug; the nozzle is provided with a core pressure-sensing cavity and a pressure-sensing core, and the pressure-sensing core is installed on the core sensor In the pressure chamber; the housing is equipped with a first filter board, a signal conditioning board and a second filter board, and the signal conditioning board is electrically connected to the first filter board, the second filter board, and the pressure-sensing core respectively; The first filter board is electrically connected to the pins of the pressure-sensitive core, the signal conditioning board is electrically connected to the second filter board using a pin connector, and the signal conditioning board is electrically connected to the first filter board through a PFC flexible cable. connected, the second filter board is electrically connected with the plug using wires.

The utility model filters the voltage signal output by the pressure-sensitive core by setting the first filter board, amplifies the filtered voltage signal and compensates the temperature through the signal conditioning board, and outputs a voltage signal or current that meets the standard according to the application scene signal, which improves the accuracy of sensor output data; by setting the second filter board to filter the power input by the docking plug, it prevents the power signal from interfering with the sensor output signal, and further improves the accuracy of sensor detection data; the second filter The board also plays the role of anti-power reverse connection, anti-surge and electrostatic protection.

As a preferred solution of the utility model, one end of the nozzle is equipped with a porous buffer screw, and the other end is sealed and connected with the casing; the drainage hole of the porous buffer screw communicates with the pressure-sensing cavity of the core body; the medium is introduced into the The pressure sensing chamber of the core can reduce the impact energy of the medium; in addition, the design of the pressure sensing chamber of the core can make the medium fully mixed and act on the surface of the pressure sensing core, making the pressure measurement more stable and accurate.

As a preferred solution of the present invention, the signal conditioning board is integrated with a signal amplification unit, an ADC sampling unit, a micro control unit, a DAC conversion unit and a V/I conversion unit that are electrically connected in sequence, and the input terminal of the signal amplification unit Connected to the output end of the first filter board, the output end of the V/I conversion unit is connected to the cable of the plug; the input of the second filter board is connected to the cable of the plug, and the output is connected to the micro control unit;

The signal amplifying unit is used to amplify the voltage signal output by the first filter board, the ADC sampling unit is used to convert the amplified voltage signal (analog signal) into a digital signal, and the micro control unit is used to amplify the The digital signal is processed (temperature compensation), the DAC conversion unit is used to convert the digital signal after temperature compensation into an analog signal, and the V/I conversion unit is used to output an analog voltage signal or an analog current signal according to demand, and It is transmitted to the monitoring terminal through the plug-in cable.

As a preferred solution of the utility model, the nozzle, the housing, and the plug are all made of electromagnetic shielding materials, which enhances the electromagnetic shielding effect of the sensor and ensures that the sensor can work stably in harsh environments; the pressure-sensitive core The joints between the body and the shell are welded, the structure is stable, and the shielding and sealing are good.

As a preferred solution of the present invention, the connector and the housing are detachably connected by fastening screws, which is convenient for cable installation and sensor maintenance.

Beneficial effect

Compared with the prior art, the utility model has the beneficial effects of:

(1) The utility model filters the voltage signal output by the pressure-sensitive core by setting the first filter board, and amplifies and temperature-compensates the filtered voltage signal through the signal conditioning board, and outputs a voltage that meets the standard according to the application scene The signal or current signal improves the accuracy of the sensor output data; by setting the second filter board to filter the power input by the plug, it prevents the power signal from interfering with the sensor output signal, and further improves the accuracy of the sensor detection data;

(2) The impact energy of the medium can be reduced by setting the porous buffer screw to introduce the medium into the pressure-sensing cavity of the core; in addition, the design of the pressure-sensing cavity of the core can make the medium fully mixed and evenly act on the surface of the pressure-sensing core, making pressure measurement easier Smooth and precise.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic diagram of the internal structure of a high-performance piezoresistive pressure sensor of the present invention;

Fig. 2 is a schematic diagram of the external structure of a high-performance piezoresistive pressure sensor of the present invention;

Fig. 3 is a schematic block diagram of the electrical connection structure of a high-performance piezoresistive pressure sensor of the present invention;

In the figure: 1. Nozzle; 2. Housing; 3. Connecting plug; 4. Core pressure sensing chamber; 5. Pressure sensing core; 6. First filter board; 7. Signal conditioning board; 8. Second filter Board; 9. Porous buffer screw; 10. Fastening screw; 11. Pin; 12. Pin connector; 13. Flexible cable; 14. Conductor.

Detailed ways

The following will clearly and completely describe the technical solutions of the utility model in conjunction with the embodiments of the utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Referring to Figures 1 and 2, this embodiment provides a high-performance piezoresistive pressure sensor, including a nozzle 1, a housing 2 and a plug 3 connected in sequence; the nozzle 1 is provided with a core pressure-sensitive Cavity 4 and pressure-sensing core body 5, described pressure-sensing core body 5 is installed in the core body pressure-sensing cavity 4; Described housing 2 interior is installed with first filter board 6, signal conditioning board 7 and second filter board 8 ( are fixed and installed by screws), the signal conditioning board 7 is electrically connected with the first filter board 6, the second filter board 8, and the pressure-sensitive core 5 respectively; the lead of the first filter board 6 and the pressure-sensitive core 5 Pin 11 is electrically connected, the signal conditioning board 7 is electrically connected to the second filter board 8 using a pin connector 12, the signal conditioning board 7 is electrically connected to the first filter board 6 through a PFC flexible flat cable 13, and the second The second filter board 8 is electrically connected to the connector plug 3 using flexible wires 14 .

In this embodiment, the voltage signal output by the pressure-sensitive core 5 is filtered by setting the first filter board 6, and the filtered voltage signal is amplified and temperature compensated by the signal conditioning board 7, and a voltage meeting the standard is output according to the application scenario The signal or current signal improves the accuracy of the sensor output data; by setting the second filter board 8 to filter the power input from the plug 3, the power signal is prevented from interfering with the sensor output signal, and the accuracy of the sensor detection data is further improved; The second filter board 8 also plays the role of preventing power reverse connection and electrostatic protection.

As a preferred solution of this embodiment, one end of the nozzle 1 is equipped with a porous buffer screw 9, and the other end is sealed with the shell 2 by laser welding; the drainage hole of the porous buffer screw 9 communicates with the core pressure sensing chamber 4; The porous buffer screw 9 is set to introduce the medium into the pressure-sensing cavity 4 of the core body, which can reduce the impact energy of the medium; in addition, the design of the pressure-sensing cavity 4 of the core body can make the medium fully mixed and evenly act on the surface of the pressure-sensing core body 5, making pressure measurement easier Smooth and precise.

As shown in Figure 3, as a preferred solution of this embodiment, the signal conditioning board 7 is integrated with a signal amplification unit, an ADC sampling unit, a micro control unit, a DAC conversion unit and a V/I conversion unit that are electrically connected in sequence, so that The input end of the signal amplifying unit is connected with the output end of the first filter board 6, and the output end of the V/I conversion unit is connected with the cable of the plug 3; the input of the second filter board 8 is connected with the plug 3 Cable connection, the output is connected with the micro control unit;

The signal amplifying unit is used to amplify the voltage signal output by the first filter board 6, the ADC sampling unit is used to convert the amplified voltage signal (analog signal) into a digital signal, and the micro control unit is used to The digital signal is processed (temperature compensation), the DAC conversion unit is used to convert the digital signal after temperature compensation into an analog signal, and the V/I conversion unit is used to output an analog voltage signal (0.5-4.5V ) or an analog current signal (4-20mA), and transmit it to the monitoring terminal through the cable connected to plug 3; For conversion of wire-based current signals, the zero-point voltage corresponds to 4mA current output, and the full-scale output corresponds to 20mA current output; the signal conditioning board 7 integrates related pads for voltage and current output, and the required output can be directly printed on the circuit board There is no need to redesign or replace the circuit board.

The pressure sensing core 5 of this embodiment is based on the silicon piezoresistive principle to realize pressure measurement, and its core component is a silicon piezoresistive chip; the silicon piezoresistive chip converts the felt medium pressure into a mV level voltage signal. The output of silicon piezoresistive chips is generally tens to hundreds of millivolts, which cannot meet the application needs of the product; at the same time, silicon materials are more sensitive to temperature, and the resistance value of diffused silicon resistors will change with temperature. When measuring in the region, the temperature has a great influence on the pressure measurement. Therefore, in this embodiment, the mV-level voltage signal output by the pressure-sensitive core 5 is amplified by the signal amplification unit to meet the application requirements of the product; The amplified voltage signal is subjected to temperature compensation processing to eliminate the influence of ambient temperature on the detection data of the pressure-sensing core 5, thereby improving the accuracy of the sensor detection data.

As a preferred solution of this embodiment, the nozzle 1, the housing 2, and the plug 3 are all made of electromagnetic shielding materials (metal materials with good shielding performance), which enhances the electromagnetic shielding effect of the sensor and ensures that the sensor can operate under severe conditions. stable work in the environment. The joints between the pressure-sensitive core and the shell are welded, the structure is stable, and the shielding and sealing properties are good.

As a preferred solution of this embodiment, the connector plug 3 is detachably connected to the housing 2 through fastening screws 10, which is convenient for cable installation and sensor maintenance.

The working principle of the sensor in this embodiment is as follows:

The cable connected to the plug 3 is used to introduce an external power supply, and the external power supply is filtered by the second filter board 8 to supply power to the signal conditioning board 7, the first filter board 6 and the pressure-sensitive core 5; the nozzle 1 is connected to the medium pipe to introduce the fluid medium, The fluid medium flows into the core pressure-sensing chamber 4 through the drainage hole of the porous buffer screw 9 and acts on the pressure-sensing core 5. The voltage signal output by the pressure-sensing core 5 is filtered by the first filter plate 6 and then transmitted to the signal conditioning board 7. After amplification and temperature compensation of the signal conditioning board 7 , a standard voltage or current signal is output, and then transmitted to the monitoring terminal through the cable connected to the plug 3 .

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included in the Within the protection scope of the present utility model.

Claims (5)

1. A high-performance piezoresistive pressure sensor is characterized in that it comprises a nozzle (1), a housing (2) and a plug (3) connected in sequence; the nozzle (1) is internally provided with a core sensor A pressure chamber (4) and a pressure-sensing core (5), the pressure-sensing core (5) is installed in the core pressure-sensing chamber (4); a first filter plate (6) is installed inside the housing (2) ), the signal conditioning board (7) and the second filter board (8), the signal conditioning board (7) is respectively connected with the first filter board (6), the second filter board (8), the pressure-sensitive core (5) Electrical connection; the first filter board (6) is electrically connected to the pin (11) of the pressure-sensitive core (5), and the signal conditioning board (7) and the second filter board (8) use pin connectors (12) Electrically connected, the signal conditioning board (7) is electrically connected with the first filter board (6) through a flexible cable (13), and the second filter board (8) and the plug (3) use a wire ( 14) Electrical connection. 2. A high-performance piezoresistive pressure sensor according to claim 1, characterized in that a porous buffer screw (9) is installed at one end of the nozzle (1), and the other end is sealed with the housing (2) ; The drainage hole of the porous buffer screw (9) communicates with the core pressure-sensing chamber (4). 3. A kind of high-performance piezoresistive pressure sensor as claimed in claim 1, is characterized in that, on the described signal conditioning board (7), is integrated with successively electrically connected signal amplifying unit, ADC sampling unit, micro control unit, DAC conversion unit and V/I conversion unit, the input end of the signal amplification unit is connected to the output end of the first filter board (6), and the output end of the V/I conversion unit is connected to the cable of the plug (3) ; The input of the second filter board (8) is connected to the cable of the plug (3), and the output is connected to the micro control unit. 4. A kind of high-performance piezoresistive pressure sensor as claimed in claim 1, is characterized in that, described nozzle (1), shell (2), connector (3) all adopt electromagnetic shielding material to make, Each seam between the pressure-sensitive core (5) and the shell (2) is welded. 5. A high-performance piezoresistive pressure sensor according to claim 1, characterized in that, the connector (3) is detachably connected to the housing (2) by fastening screws (10).

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