A pressure sensor test calibration fixture

Abstract

This invention discloses a pressure sensor testing and calibration fixture, relating to the field of pressure sensor testing technology. The invention includes a base plate and a top cover. The top cover is mounted on the top of the base plate, and a PCB board is fixedly connected to the bottom of the base plate. This invention innovatively modifies the air intake method of existing pressure sensor testing and calibration fixtures. An overload transmission mechanism is designed to match the pressure threshold of the corresponding pressure sensor. Pressurized air intake is transformed into single-sided mechanical transmission air pumping. Accompanying the rotation of the shaft, multiple eccentric wheels located inside the top cover work synchronously without interfering with each other. The rotation of the sleeve plate causes the piston rod connected to the triangular rod to press down, continuously applying pressure to the piston chamber connected to the pressure sensor's air nozzle. When the pressure reaches the safety threshold for pressure sensor measurement, the pressure is actively released. The combined arm pushes the upper pressure sleeve of the sliding rod, transferring excess pressure to the cylinder, protecting the pressure sensor and the fixture itself from damage.

Description

Technical Field

[0001] This invention relates to the field of pressure sensor testing technology, specifically to a pressure sensor testing and calibration fixture. Background Technology

[0002] Pressure sensor testing and calibration fixtures are key equipment for ensuring the accuracy of pressure sensor measurements. They provide a standard pressure environment for the pressure sensor, compare its output signal with the standard value for calibration, and typically consist of a pressure generating system, a standard pressure measuring device, connecting pipelines and valves, and a signal acquisition and processing system. The pressure generating system generates different pressure values, which are applied to the pressure sensor and the standard pressure measuring device through the connecting pipelines. The standard pressure measuring device provides a high-precision pressure value as a reference. The pressure sensor converts the sensed pressure into an electrical signal output. The signal acquisition and processing system collects and compares the two signals, calculates the deviation between the pressure sensor's measured value and the standard value, and calibrates and standardizes the pressure sensor through software algorithms, generating calibration curves or correction coefficients to compensate for measurement errors and improve measurement accuracy.

[0003] Regarding the design of pressure sensor testing and calibration fixtures for compatible fixed testing of batch pressure sensors, as mentioned in the patent text with publication number CN218239165U, 32 pressure sensor cores can be tested online through the combination of calibration fixtures. At the same time, the pressure of each line is controllable and does not affect each other. Furthermore, multiple types of sensors can be adapted by replacing the board. However, the overall calibration fixture lacks overpressure protection. When the pressure exceeds the safety threshold set by the sensor or the fixture, it cannot automatically cut off the pressure source or take pressure relief measures, resulting in damage to the pressure sensor and the fixture itself due to overpressure, affecting personnel operation and equipment safety.

[0004] To address this, we propose a pressure sensor testing and calibration fixture. Summary of the Invention

[0005] The purpose of this invention is to provide a pressure sensor testing and calibration fixture to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a pressure sensor testing and calibration fixture, comprising a base plate and a top cover, wherein the top cover is installed on the top of the base plate, a PCB board is fixedly connected to the bottom of the base plate, a needle plate is installed on the top of the base plate and inside the top cover, probes are uniformly fixed at the bottom of the needle plate and extend to the bottom of the PCB board, positioning strips are symmetrically installed inside the top cover, and pressure sensor bodies are installed in the grooves on both sides of the positioning strips;

[0007] A piston chamber is uniformly fixed inside the top cover, and the vent at the bottom of the piston chamber is connected to the pressure sensor body. A sealing sleeve is uniformly installed on the inner wall at the bottom of the top cover, and the sealing sleeve abuts against the pressure sensor body. An overload transmission mechanism is installed inside the piston chamber.

[0008] Furthermore, a control box is fixed to one side of the top cover by bolts, and rotating shafts are symmetrically and movably connected to the inner walls of both sides of the top cover. Eccentric wheels are evenly fitted and fixed on the rotating shafts. The output end of the motor installed in the control box passes through one side of the top cover and is correspondingly connected to the rotating shaft.

[0009] Furthermore, a sleeve disc is movably connected to the eccentric wheel, and a slide rod is movably connected to one side of the sleeve disc.

[0010] Furthermore, the overload transmission mechanism includes a mounting plate, a piston rod, a triangular rod, and a combined arm. A triangular rod is movably connected to one side of the sleeve, and a mounting plate is movably connected to the triangular rod. Piston rods are symmetrically installed at the bottom of the mounting plate, and the piston rods are slidably connected to the piston chambers. A combined arm is movably connected to the triangular rod and the sleeve.

[0011] Furthermore, a through hole is provided on the central shaft of the combined arm, one end of the slide rod passes through the through hole on the central shaft of the combined arm and is fixedly connected to a fixing sleeve, and a pressure sleeve is slidably connected to the outer wall of the slide rod located on one side of the combined arm.

[0012] Furthermore, a cylinder is fixed to one side of the fixed sleeve by bolts, and a sleeve post is slidably connected to one end of the cylinder and located inside the fixed sleeve. One side of the sleeve post passes through the upper channel of the fixed sleeve and abuts against the outer wall of the pressure sleeve.

[0013] Furthermore, the top cover, positioning strip, and needle plate are provided with corresponding positioning holes, positioning bolts are installed in the positioning holes, and a baffle is fixed to the side of the positioning strip by bolts.

[0014] The method for using this pressure sensor testing and calibration fixture is as follows:

[0015] Assembly and debugging: disassemble the baffles on both sides of the base plate, fix the needle plate to the PCB board, and match the needle plate at the corresponding probe position with the pressure sensor.

[0016] Place the pressure sensors one by one into the grooves of the positioning strip, while ensuring that the pins of the pressure sensors are aligned with the probes. Then place the top cover of the corresponding air passage, fix the positioning bolt, and begin differential pressure and absolute pressure detection.

[0017] In online testing, the cylinder inside the top cover is matched with the safe pressure threshold of the pressure sensor. The upper limit of the pressure of the corresponding cylinder is adjusted, and the control box drives the rotating shaft to rotate. Accompanied by the rotation of multiple eccentric wheels, the movement of the sleeve pushes the piston rod connected by the triangular rod to pressurize the piston chamber. Air enters from both sides of the pressure sensor at the same time, and the internal sensitive element deforms, displaces or changes other physical quantities. These changes are transmitted through electrical signals to obtain the differential pressure value of the pressure sensor. If one side of the pressure sensor is blocked and the other side is ventilated, the absolute pressure of the pressure sensor is measured.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. In this invention, a top cover is installed on the original test plate. The overload transmission mechanism can be matched with the pressure threshold of the corresponding pressure sensor. The pressurization ventilation is transformed into single-sided mechanical transmission air pumping. With the rotation of the shaft, multiple sets of eccentric wheels located in the top cover work simultaneously. The rotation of the sleeve realizes the downward movement of the piston rod connected to the triangular rod side, continuously applying pressure to the piston chamber connected to the end of the pressure sensor. While continuously compressing the air, the pressure sensor outputs a signal. At the same time, when the pressure sensor safety threshold is reached, the cylinder on the side of the combined arm is actively controlled to reduce the pressure. The rotation of the sleeve can no longer continuously pressurize, and the upper pressure sleeve of the slide rod is pushed by the combined arm to complete the automatic pressure relief work. Meanwhile, the subsequent detection of the pressure sensor on the side of the shaft is not affected.

[0020] 2. This invention mainly comprises a base plate, a needle plate, a PCB board, a limiting strip, and a top cover. The testing and calibration fixture has a simple structure and is easy to disassemble and install. It can perform online testing of 6 groups of pressure sensors at a time, resulting in high testing efficiency. Using this fixture for testing and calibration can significantly shorten the product testing cycle, allowing products on the production line to enter the next process more quickly, greatly improving production efficiency and reducing production costs. Furthermore, the online testing method can acquire various performance data of the sensors in real time. Once a sensor performance abnormality is detected, it can be immediately screened and processed, effectively preventing unqualified products from entering subsequent production stages and strongly ensuring the stability and reliability of product quality. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the pressure sensor testing and calibration fixture of the present invention;

[0022] Figure 2 This is a schematic diagram of the disassembly of the upper baffle of the pressure sensor testing and calibration fixture of the present invention;

[0023] Figure 3 This is a schematic diagram of the disassembly of the top cover and top plate of the pressure sensor testing and calibration fixture of the present invention;

[0024] Figure 4This is a schematic diagram of the disassembly of the top cover of the pressure sensor testing and calibration fixture of the present invention;

[0025] Figure 5 This is a schematic diagram of the connection structure between the pins of the multiple pressure sensors and the needle plate of the present invention;

[0026] Figure 6 This is a schematic diagram of the installation of the overload transmission mechanism on the piston chamber of the present invention;

[0027] Figure 7 This is a schematic diagram of the cylinder structure connected to the slide rod side of the present invention.

[0028] In the diagram: 1. Base plate; 2. PCB board; 3. Needle plate; 4. Top cover; 5. Control box; 6. Positioning strip; 7. Positioning bolt; 8. Rotating shaft; 9. Eccentric wheel; 10. Piston chamber; 11. Sleeve disc; 12. Overload transmission mechanism; 121. Hanging plate; 122. Piston column; 123. Triangular rod; 124. Combined arm; 13. Slide rod; 14. Cylinder; 15. Fixed sleeve; 16. Sleeve column; 17. Pressure sleeve. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see Figure 1-7 The present invention provides a technical solution:

[0031] Example 1: As Figure 1 To perform the pressure sensor calibration test, a high-precision pressure calibrator must be prepared in advance as a standard pressure source to provide an accurate and known pressure value for comparison and calibration of the pressure sensor under test. A ventilation device, such as an air pump, gas pipeline, valve, etc., is also required to introduce gas at different pressures into the pressure sensor. Data acquisition equipment, such as a digital multimeter, data acquisition card, etc., is also required to record the output signal of the pressure sensor. The pressure sensor is correctly installed on the test interface of the ventilation device, ensuring a firm connection and no gas leakage. According to the sensor's instruction manual, the power supply and signal output lines of the sensor are connected to the data acquisition device. A test environment with relatively stable temperature and humidity and no strong electromagnetic interference or vibration is selected.

[0032] This invention modifies the original ventilation pipeline, which also vents air to both ends of the pressure sensor. One end is pressurized by mechanical transmission. Compared with air pumps at both ends, after the pressure sensor reaches the safety threshold, it is not possible to quickly cut off the pressure source or automatically depressurize. The pressure sensor and the tooling itself are damaged due to overpressure, resulting in large errors in the subsequent data collection.

[0033] like Figure 3 and Figure 4 As shown, a control box 5 is installed on the side of the top cover 4. The drive component inside the control box 5 controls the rotation of the rotating shaft 8 inside the top cover 4. Multiple sets of eccentric wheels 9 are arranged on the rotating shaft 8 and corresponding to the pressure sensor fixed at the bottom. A mounting plate 11 is fitted on the eccentric wheel 9, as shown. Figure 6 As shown, the overload transmission mechanism 12 is installed on the side of the sleeve 11;

[0034] Here is a detailed description of the pressure overload adjustment. The main body of the overload transmission mechanism 12 is a triangular rod 123. One end of the triangular rod 123 is movably connected to the sleeve plate 11, and the other side is movably connected to the combined arm 124. The bent end of the combined arm 124 is movably connected to the sleeve plate 11. A sliding rod 13 is also slidably connected at the rotation center of the combined arm 124. The end of the sliding rod 13 is movably connected to the triangular rod 123 and the sleeve plate 11. With the rotation of the rotating shaft 8, the rotation of the eccentric wheel 9 realizes the up and down movement of the sleeve plate 11, thereby pushing the entire triangular rod 123 and the hanging plate 121 connected to the triangular rod 123 to move.

[0035] A piston rod is symmetrically fixed at the bottom of the mounting plate 121. The piston rod is slidably connected to the piston chamber 10. As the piston rod slides down, it continuously pressurizes the connected pressure sensor. Meanwhile, the air pump located at the other air inlet of the pressure sensor circulates air. Both apply pressure to the pressure sensor at the same time, causing the internal sensitive element to deform, displace, or change other physical quantities, which are then converted into electrical signals for transmission, thereby obtaining the differential pressure value of the pressure sensor.

[0036] Furthermore, a pressure sleeve 17 is added to the entire slide bar 13, such as Figure 7 As shown, a fixed sleeve 15 is fixed to the end of the slide rod 13, and a cylinder 14 is installed on the side of the fixed sleeve 15. The cylinder 14 can be fixed and the air pressure is regulated. A sleeve post 16 is slidably connected to the side of the cylinder 14. The end of the sleeve post 16 extends through the groove of the outer wall of the fixed sleeve 15 and abuts against the pressure sleeve 17. When the eccentric wheel 9 drives the sleeve plate 11 to rotate, it will also apply pressure to the combined arm 124, causing the combined arm 124 to bend.

[0037] At the same time, the pressure sleeve 17 on the side of the slide bar 13 is squeezed, and the pressure sleeve 17 will push the sleeve column 16 when it is squeezed. The sleeve column 16 is connected to the cylinder 14. After the internal pressure value of the cylinder 14 is set, the combined arm 124 cannot squeeze the sleeve column 16 through the pressure sleeve 17, causing the sleeve plate 11 to squeeze the piston rod downward as a whole, and continuously pressurize and ventilate the pressure sensor.

[0038] When the safety threshold set by cylinder 14 is reached, the rotation of the sleeve 11 applies pressure to the combined arm 124, pushing the pressure sleeve 17 to move. The sleeve 16 slides inside cylinder 14, and the rotation of the eccentric wheel 9 can no longer drive the piston rod to continuously press down the air in the piston chamber 10. However, the eccentric wheel 9 as a whole is not affected. The eccentric wheel 9, which is limited in pressure, rotates on its own. For other pressure sensors that have not reached the safety threshold of cylinder 14, pressure can still be applied by rotating the eccentric wheel 9.

[0039] It should be noted that the air pressure value set in cylinder 14 can be automatically adjusted according to the pressure sensor measurement threshold. Through mechanical transmission, pressure is applied to one side of the pressure sensor, and cylinder 14 acts as a buffer. When the pressure sensor reaches the measurement threshold, the mechanical structure is activated to transfer the pressure, preventing damage to the pressure sensor and the tooling itself due to overpressure, thus ensuring the safety of personnel and equipment. Damage to the calibration tooling here is mostly due to loose sealing gaskets at the connection points.

[0040] Example 2: For pressure sensors placed within a test calibration fixture, such as... Figure 1 As shown, the tooling adopts a composite assembly method. The top is the top cover 4, and the bottom of the top cover 4 is a specially designed positioning strip 6. The positioning strip 6 is customized according to the shape of the pressure sensor. The slots on both sides are similar to the shape of the pressure sensor, which facilitates the placement and fixing of the pressure sensor.

[0041] Secondly, a needle plate 3 is installed at the bottom of the positioning strip 6, and corresponding probes are installed on the needle plate 3. A PCB board 2 is also fixed on the base plate 1. The needle plate 3 is fixed on the PCB board 2 with screws according to the corresponding through holes on the PCB board 2 and the needle plate 3. After the pressure sensor is placed in the groove of the product positioning strip 6, the pressure sensor positioning strip 6 is aligned and limited by the positioning bolt 7 so that the pins of the pressure sensor are in complete contact with the probes on the needle plate 3. At any time, the baffle is fixed on both sides of the product positioning strip 6 to further fix the pressure sensor so that it will not move or fall off the product positioning strip 6 when the tooling shakes. This would cause the pins of the pressure sensor to not be in complete contact with the tooling probes, resulting in communication abnormalities during testing. The air nozzles on the top cover 4 correspond one-to-one with the air nozzles of the pressure sensor to ensure that the air can be accurately delivered to the pressure sensor when the tooling is vented.

[0042] When performing absolute pressure measurement, the piston rod 122 is used to pressurize and add gas, while the gas nozzle on the other side is in a blocked state. This fixture can measure products with two different pressurization forms, absolute pressure and differential pressure, and has a wider range of applications.

[0043] The working principle of this invention is as follows: the pressure sensors are installed in batches on the calibration fixture, the baffles on both sides of the base plate 1 are removed, the needle plate 3 is fixed to the PCB board 2, and the needle plate 3 at the corresponding probe position is matched with the pressure sensor pin.

[0044] Place the pressure sensors one by one into the inner groove of the positioning strip 6, while ensuring that the pins of the pressure sensors are aligned with the probes. Then place the top cover 4 of the corresponding air passage, fix the positioning bolt 7, and begin differential pressure and absolute pressure detection.

[0045] The cylinder 14 inside the top cover 4 is matched with the safe pressure threshold of the pressure sensor. The corresponding cylinder 14 is adjusted to meet the upper pressure limit. The control box 5 drives the rotating shaft 8 to rotate, accompanied by the rotation of multiple eccentric wheels 9. The movement of the sleeve 11 pushes the piston column 122 connected to the triangular rod 123 to pressurize the piston chamber 10. Air enters from both sides of the pressure sensor at the same time, and the internal sensitive element undergoes deformation, displacement or other physical quantity changes. These changes are transmitted through electrical signals to obtain the differential pressure value of the pressure sensor. When one side of the pressure sensor is blocked and the other side is ventilated, the absolute pressure of the pressure sensor is measured.

[0046] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A pressure sensor test calibration fixture comprising a base plate (1) and a top cover (4), characterized in that, A top cover (4) is installed on the top of the base plate (1), and a PCB board (2) is fixedly connected to the bottom of the base plate (1). A needle plate (3) is installed on the top of the base plate (1) and inside the top cover (4). Probes are evenly fixed at the bottom of the needle plate (3) and extend to the bottom of the PCB board (2). Positioning strips (6) are symmetrically installed inside the top cover (4), and pressure sensor bodies are installed in the grooves on both sides of the positioning strips (6). The top cover (4) has a piston chamber (10) evenly fixed inside, and the bottom vent of the piston chamber (10) is connected to the pressure sensor body. The bottom inner wall of the top cover (4) is evenly equipped with a sealing sleeve, and the sealing sleeve abuts against the pressure sensor body. An overload transmission mechanism (12) is installed inside the piston chamber (10). A control box (5) is fixed to one side of the top cover (4) by bolts. Rotating shafts (8) are symmetrically and movably connected to the inner walls of both sides of the top cover (4). Eccentric wheels (9) are evenly fitted and fixed on the rotating shafts (8). The output end of the motor installed in the control box (5) passes through one side of the top cover (4) and is correspondingly connected to the rotating shafts (8). A sleeve disc (11) is movably connected to the eccentric wheel (9), and a slide rod (13) is movably connected to one side of the sleeve disc (11). The overload transmission mechanism (12) includes a mounting plate (121), a piston rod (122), a triangular rod (123), and a combined arm (124). The triangular rod (123) is movably connected to one side of the sleeve (11). The mounting plate (121) is movably connected to the triangular rod (123). The piston rod (122) is symmetrically installed at the bottom of the mounting plate (121), and the piston rod (122) is slidably connected to the piston chamber (10). The combined arm (124) is movably connected to the triangular rod (123) and the sleeve (11). A through hole is provided on the central axis of the combined arm (124). One end of the slide rod (13) passes through the through hole on the central axis of the combined arm (124) and is fixedly connected to a fixed sleeve (15). A pressure sleeve (17) is slidably connected to the outer wall of the slide rod (13) and located on one side of the combined arm (124). A cylinder (14) is fixed to one side of the fixed sleeve (15) by bolts. A sleeve post (16) is slidably connected to one end of the cylinder (14) and located inside the fixed sleeve (15). One side of the sleeve post (16) passes through the upper channel of the fixed sleeve (15) and abuts against the outer wall of the pressure sleeve (17).

2. The pressure sensor test and calibration fixture of claim 1, wherein, The top cover (4), positioning strip (6) and needle plate (3) are provided with corresponding positioning holes, and positioning bolts (7) are installed in the positioning holes. A baffle is fixed to the side of the positioning strip (6) by bolts.

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