A quartz flexible accelerometer core clamping force monitoring device and monitoring method

Abstract

The application relates to a quartz flexible accelerometer watch core clamping force monitoring device and a monitoring method. The device comprises an upper magnetic conducting ring component, a swing component, a lower magnetic conducting ring component, a connecting ring, an isolation ring and a shell; the upper and lower magnetic conducting ring components and the swing component are connected through the connecting ring, the upper and lower magnetic conducting rings and the connecting ring are welded, and a watch core is formed; the watch core is connected with the shell through the isolation ring and is connected through glue, and a monitoring device is formed; the swing component is composed of a swing piece and a torque coil; a beam on the swing piece is a rigid beam, and the thickness of the beam is the same as the thickness of a swing tongue; gold films on both sides of the swing tongue and end faces of the upper and lower magnetic conducting rings form a differential capacitor sensor, and differential capacitance is led out through two insulators; the device comprises a differential capacitor detection circuit, a digital universal meter and a computer. In the application, the beam of the swing piece in the quartz flexible accelerometer is changed from a flexible beam to a rigid beam, the swing tongue loses the freedom of swing tongue deflection, and then the monitoring of the clamping force of the watch core is realized through the monitoring of the differential capacitor sensor of the accelerometer.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sensors, and particularly relates to a quartz flexible accelerometer watch core clamping force monitoring device and a monitoring method. BACKGROUND

[0002] The quartz flexible accelerometer is the most widely used accelerometer at present, and is used in navigation and guidance systems of spaceflight, aviation, navigation and land use, and is also widely used in the fields of gravity and gravity gradient measurement and oil exploration.

[0003] The quartz flexible accelerometer is composed of an upper magnetic ring component, a pendulum component, a lower magnetic ring component, a connecting ring, an isolation ring and a shell, as shown in the figure. Figure 1 The upper and lower magnetic ring components and the pendulum component are connected through the connecting ring, the upper and lower magnetic rings and the connecting ring are laser welded, and the watch core is formed; the watch core is connected through the isolation ring and the shell, and the accelerometer is formed. The pendulum component is composed of a pendulum piece and a torque coil, and the pendulum tongue of the pendulum piece and the torque coil form a detection mass for sensing acceleration. The upper (lower) magnetic ring component includes an upper (lower) magnetic ring, a magnetic steel, a magnetic pole piece and a thermal magnetic compensation ring, and forms a magnetic circuit. The torque coil is located in the working air gap of the magnetic circuit, and forms a permanent magnet type torque motor. At the same time, the gold film plated on the pendulum tongue and the end faces of the upper and lower magnetic rings form a differential capacitive sensor.

[0004] The quartz flexible accelerometer is a differential closed loop working accelerometer. When there is no acceleration input, the detection mass composed of the pendulum tongue and the torque coil is in the "electric zero position" of the differential capacitive sensor. When there is acceleration input, the detection mass deflects due to the inertial force, deviates from the "electric zero position", and the differential capacitive sensor generates an output. The output is converted into a torque feedback current by a servo circuit and input to the torque coil, to generate an electromagnetic feedback torque to make the detection mass return to the "electric zero position". After reaching a steady state, there is a deviation angle between the position of the detection mass and the "electric zero position". The electromagnetic feedback torque generated by the deviation angle difference is balanced with the inertial torque. Therefore, the feedback current in the torque coil corresponds to the input acceleration, and the size and direction of the input acceleration can be obtained by detecting the size and direction of the torque feedback current.

[0005] The table core is a key component in a quartz flexible accelerometer. In order to ensure the stability of the performance parameters of the accelerometer under various working conditions, the connection state of the upper and lower magnetic ring components and the pendulum component in the table core must be kept stable. In order to ensure that the connection state of the upper and lower magnetic ring components and the pendulum component in the table core remains stable under various working conditions, a certain clamping force must be maintained between the three components in the table core. During the assembly of the accelerometer, the upper and lower magnetic ring components and the pendulum component are first clamped by an assembly tool, a pre-clamping force is applied, and compressive strain is generated in the three components; then the connecting ring is assembled, at which time the connecting ring is in a free state, and laser welding is performed between the connecting ring and the upper and lower magnetic rings; after that, the assembly tool is removed, at which time the compressive strain of the upper and lower magnetic ring components and the pendulum component decreases, the connecting ring is deformed in tension, and tensile strain is generated; after force balance is achieved, the tensile force generated by the tensile strain of the connecting ring maintains a certain pressure between the upper and lower magnetic ring components and the pendulum component, so that the upper and lower magnetic ring components and the pendulum component continue to maintain a certain compressive strain. This pressure is the clamping force of the table core.

[0006] The size of the table core clamping force is related to the pre-clamping force applied during assembly and also related to the structural dimensions of the connecting ring and other parts. The table core clamping force changes under different working conditions. Since the material of the pendulum plate is quartz glass, and the materials of the upper and lower magnetic rings and the connecting ring are low-expansion alloys, the thermal expansion coefficients of these two materials are different, so when the temperature changes, the thermal deformation amounts of the parts are different, at which time the table core clamping force changes. The contact surface between the upper and lower magnetic rings and the pendulum plate is not ideal mirror surface contact, but there is a certain microscopic unevenness, and after the accelerometer experiences vibration, impact and other effects, the contact stiffness between the upper and lower magnetic rings and the pendulum plate changes slightly, at which time the table core clamping force also changes. The upper and lower magnetic rings and the connecting ring are connected by laser welding, and as the accelerometer is stored and worked for a long time, the stress distribution of the laser welding changes, at which time the table core clamping force also changes.

[0007] When the table core clamping force changes, the compressive strain of the upper and lower magnetic rings and the pendulum plate changes, causing the capacitance values of the two capacitors formed by the pendulum plate tongue gold film and the end surfaces of the upper and lower magnetic rings to change nonlinearly, thereby changing the "electric zero" of the differential capacitive sensor of the accelerometer; the change in the compressive strain of the pendulum plate is also transmitted to the flexible beam, causing the stress state of the flexible beam to change; both of these will change the bias value of the accelerometer, i.e. affect the performance accuracy of the accelerometer. Even worse, when the table core clamping force is not appropriate, it may decrease to zero under certain working conditions, at which time the upper and lower magnetic ring components and the pendulum component may move radially, causing the performance accuracy of the accelerometer to decrease seriously, or even losing function.

[0008] Therefore, it is necessary to monitor the table core clamping force under different working conditions, optimize the pre-clamping force applied in the assembly process and the laser welding process parameters according to the monitoring results, ensure that the table core clamping force is appropriate and stable, and thus ensure the performance accuracy and reliability of the accelerometer. SUMMARY

[0009] The purpose of the present application is to overcome the shortcomings of the prior art and provide a quartz flexible accelerometer table core clamping force monitoring device and monitoring method.

[0010] One of the above-mentioned purposes of the present application is achieved by the following technical solutions:

[0011] A quartz flexible accelerometer table core clamping force monitoring device, characterized in that:

[0012] The upper and lower magnetic ring components and the pendulum component are connected through the connecting ring, the upper and lower magnetic rings and the connecting ring are welded, and the table core is formed; the table core is connected between the isolation ring and the shell through adhesive connection, and the monitoring device is formed; wherein the pendulum component is composed of a pendulum piece and a torque coil; the beam on the pendulum piece is a rigid beam, and the thickness of the beam is the same as the thickness of the pendulum tongue; the gold film on both sides of the pendulum tongue and the end faces of the upper and lower magnetic rings form a differential capacitor sensor, and the differential capacitor is led out through two insulators;

[0013] The differential capacitor detection circuit is used to convert the differential capacitor led out by the insulator into voltage;

[0014] The digital multimeter is used to measure the voltage output by the differential capacitor detection circuit;

[0015] The computer is used to monitor the voltage measured by the digital multimeter in real time, record the number and display.

[0016] The second of the above-mentioned purposes of the present application is achieved by the following technical solutions:

[0017] A quartz flexible accelerometer table core clamping force monitoring method, characterized in that: based on the above-mentioned detection device, comprising the following steps:

[0018] Step 1, the capacitance of the differential capacitor sensor is led out through three insulators;

[0019] Step 2, the differential capacitor value is converted into voltage value through the differential capacitor detection circuit, and the converted voltage is output to the digital multimeter;

[0020] Step 3, the output voltage of the differential capacitor detection circuit is measured by the digital multimeter, and the data is output to the computer;

[0021] Step 4, real-time monitoring of the digital multimeter measured voltage by computer, recording and displaying.

[0022] The present application has the advantages and positive effects:

[0023] 1. The present application changes the beam of the pendulum tongue in the quartz flexible accelerometer detection device from a flexible beam to a rigid beam, so that the pendulum tongue loses the freedom of rotation around the pendulum tongue, and then monitors the differential capacitor sensor of the accelerometer to monitor the clamping force of the watch core.

[0024] 2. In the method of the present application, the differential capacitor sensor is led out through an insulator, and a differential capacitor detection circuit is connected to convert the differential capacitor into voltage, and then a digital multimeter and a computer are connected to realize real-time monitoring of the differential capacitor.

[0025] 3. Compared with the normal accelerometer, the present application only changes the beam of the pendulum tongue, and the other design states and assembly process states are the same, and from the outside it is still an "accelerometer", so it can be used together with the normal accelerometer for various environmental stress tests such as high and low temperature, vibration and impact, and like the normal accelerometer which can monitor its acceleration output during environmental stress test, the present application can monitor the "clamping force" output during environmental stress test. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a sectional view of the existing quartz flexible accelerometer;

[0027] Figure 2 is a structure diagram of the existing normal flexible beam pendulum tongue, 2a is a front view; 2b is a side view;

[0028] Figure 3 is a structure diagram of the rigid beam pendulum tongue of the present application, which loses the freedom of rotation around the beam, 3a is a front view; 3b is a side view;

[0029] Figure 4 is a watch core using the rigid beam pendulum tongue of the present application, 4a is a longitudinal sectional view; 4b is a left view;

[0030] Figure 5a is a longitudinal sectional view of the accelerometer using the rigid beam pendulum tongue of the present application;

[0031] Figure 5b is a left view of the accelerometer using the rigid beam pendulum tongue of the present application;

[0032] Figure 6 is a block diagram of the watch core clamping force monitoring system of the present application;

[0033] Figure 7 is an output voltage-clamping force calibration curve of an actual device of the present application;

[0034] Figure 8 is the output voltage-temperature test curve of an actual device of the present application. DETAILED DESCRIPTION

[0035] The structure of the present application is further described below in connection with the drawings and by way of examples. It should be noted that the examples are descriptive rather than limiting.

[0036] In a quartz flexible accelerometer, the gold films on both sides of the balance beam tongue form capacitors with the end faces of the upper and lower magnetic guide rings, respectively, and the two capacitors form a differential capacitor sensor for detecting the deflection of the balance beam tongue. As described in the background art, when the clamping force of the watch movement changes, the "electric zero position" of the differential capacitor sensor changes, resulting in a change in the output of the differential capacitor sensor. Therefore, the change in the output of the differential capacitor sensor reflects both the deflection of the balance beam tongue and the change in the clamping force of the watch movement. If the monitoring device adopts the same structure as the quartz flexible accelerometer, but replaces the flexible beam with a rigid beam so that the balance beam tongue cannot deflect, then the change in the output of the differential capacitor sensor only reflects the change in the clamping force of the watch movement, and can be used to monitor the clamping force of the watch movement.

[0037] The structure of a normal balance beam is shown in Figure 2 , and the thickness of the beam is only 0.02mm-0.03mm. The structure of the balance beam after replacing the flexible beam with a rigid beam is shown in Figure 3 , and the thickness of the beam is the same as the thickness of the tongue, so the tongue loses the degree of freedom of deflection around the beam.

[0038] The watch movement is assembled using the rigid beam balance beam, as shown in Figure 4 , and then the watch movement is assembled into the case, and the monitoring device of the present application is assembled, as shown in Fig. 5. The balance beam 5, the upper magnetic guide ring 3, the lower magnetic guide ring 6, and the connecting ring 4 are assembled into the watch movement, and the assembly process parameters are the same as the actual assembly process parameters. The watch movement, the isolation ring 2, and the case 1 are assembled into the monitoring device of the present application, and the assembly process parameters are also the same as the actual assembly process parameters. In the monitoring device of the present application, the gold films on both sides of the balance beam tongue form a differential capacitor sensor with the end faces of the upper and lower magnetic guide rings, the differential capacitor is led out through the insulator 7 and the insulator 8, an external differential capacitor detection circuit converts the differential capacitor into a voltage, and then a digital multimeter measures the output voltage of the differential capacitor detection circuit, and a computer is connected to monitor the measured voltage of the digital multimeter in real time, record the data, and display the data.

[0039] Since the monitoring device of the present application is only different from the normal accelerometer in the beam of the pendulum, other design states and assembly process states are the same, and it is still an "accelerometer" from the outside, so it can be subjected to various environmental stress tests such as high and low temperature, vibration and impact together with the normal accelerometer, and like the normal accelerometer can monitor its acceleration output when subjected to environmental stress tests, the device of the present application can monitor its "clamping force" output when subjected to environmental stress tests.

[0040] In order to verify the effectiveness of the monitoring device of the present application, an actual monitoring device was subjected to output voltage-clamping force calibration test in the state of the watch core, that is, the clamping force of the watch core was changed by an assembly tool, and the change of the output voltage was measured, Figure 7 The calibration curve thereof is shown in the figure, and it can be seen that the output voltage changes with the change of the clamping force, and the fitting slope of the voltage / clamping force is 0.03 mV / N. The monitoring device was placed in a high and low temperature chamber, and the output voltage thereof was measured at -20℃, 0℃ and 30℃, and the measured curve is shown in the figure Figure 8 The fitting slope of the voltage / temperature is 0.004 mV / ℃, and thus the scale factor of the clamping force / temperature is about 0.13 N / ℃.

[0041] Although the embodiments of the present application and the drawings are disclosed for the purpose of illustration, those skilled in the art can understand that various substitutions, changes and modifications are possible without departing from the spirit of the present application and the appended claims, and thus the scope of the present application is not limited to the disclosed contents of the embodiments and the drawings.

Claims

1. A device for monitoring the clamping force of a quartz flexible accelerometer core, characterized in that: The device includes an upper magnetic ring component, a pendulum component, a lower magnetic ring component, a connecting ring, an isolation ring, and a housing. The upper and lower magnetic ring components and the pendulum component are connected by the connecting ring, and the upper and lower magnetic ring components and the connecting ring are welded together to form the core. The core is glued to the housing through the isolation ring to form a monitoring device. The pendulum component consists of a pendulum plate and a torque coil. The beam on the pendulum plate is a rigid beam, and the thickness of the beam is the same as the thickness of the pendulum tongue. The gold films on both sides of the pendulum plate and the end faces of the upper and lower magnetic ring components form a differential capacitive sensor, and the differential capacitor is led out through two insulators. It includes a differential capacitance detection circuit, used to convert the differential capacitance led out from the insulator into voltage; Includes a digital multimeter for measuring the output voltage of the differential capacitor detection circuit; It includes a computer for real-time monitoring of voltage measurements taken by digital multimeters, recording and displaying the readings.

2. A monitoring method based on the quartz flexible accelerometer core clamping force monitoring device according to claim 1, characterized in that: Step 1: Lead out the capacitance of the differential capacitive sensor through two insulators; Step 2: Convert the differential capacitance value into a voltage value through the differential capacitance detection circuit, and output the converted voltage to the digital multimeter; Step 3: Use a digital multimeter to measure the output voltage of the differential capacitor detection circuit and output the data to the computer. Step 4: Monitor the voltage measured by the digital multimeter in real time using a computer, and record and display the readings.

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