Piezoelectric pressure sensor for explosion field

Abstract

The invention discloses a piezoelectric pressure sensor for an explosion field, and the sensor comprises a housing, and a diaphragm, a force transmission block, two piezoelectric crystal plates, an inertia compensation mass block and an electrode plate which are disposed on the surface of the housing and in the housing. The two piezoelectric wafers generate positive charges on the upper surfaces and negative charges on the lower surfaces, and due to the fact that the two piezoelectric wafers are connected in series, the sensor outputs voltage signals in direct proportion to shock wave pressure. When the sensor is subjected to the action of acceleration, the inertia compensation mass block can generate opposite acting force on the two piezoelectric crystal plates, so that the two piezoelectric crystal plates respectively generate opposite voltage signals, and the compensation of acceleration parasitic output signals can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric pressure sensors, in particular to an explosion field piezoelectric pressure sensor. Background Art

[0002] The explosion and combustion process of the warhead is often accompanied by strong parasitic effects such as mechanical shock and vibration, thermal shock, and electromagnetic waves. These parasitic effects will cause certain parasitic outputs to the shock wave pressure sensor and acceleration sensor. Especially in the near field of the explosion, the interference signal is superimposed on the air shock wave signal, causing the measured shock wave signal to become distorted, seriously affecting the shock wave measurement and causing the high-impact acceleration sensor to produce serious lateral parasitic output.

[0003] Mechanical vibration and shock are the most important parasitic effects in the shock wave measurement process. Under damage conditions, strong mechanical shocks include seismic waves and mechanical shocks on the sensor mounting plate. Most of the piezoelectric shock wave pressure sensors currently used do not have inertia compensation structures. Piezoelectric shock wave pressure sensors are particularly sensitive to mechanical shock and seismic waves. Their output values ​​may even be larger than the output values ​​under actual pressure excitation. At the same time, they will also stimulate the high-frequency modes of the sensor system. If corresponding measures are not taken, the measured shock wave pressure signal will inevitably be severely distorted.

[0004] Existing piezoelectric pressure sensors with inertia compensation function are all charge output type. The compensation crystal group structure requires four piezoelectric chips, which greatly increases the difficulty of crystal group assembly and places extremely high requirements on the processing quality of the chips. If the chip thickness is too thin, it is easy to break during the assembly process; if the chip is too thick, it will greatly reduce the natural frequency of the sensor. Summary of the Invention

[0005] In view of the defects or shortcomings of the prior art, the present invention provides an explosion field piezoelectric pressure sensor.

[0006] To this end, the explosion field piezoelectric pressure sensor provided by the present invention includes a housing and leads. The housing has a component accommodating chamber, an axial end of the component accommodating chamber has a sensing opening, and a diaphragm is provided at the sensing opening. An insulating film, a force transmission block, a first piezoelectric wafer, an inertia compensation mass block, an electrode sheet, and a second piezoelectric wafer are installed in the component accommodating chamber. The diaphragm, the insulating film, the force transmission block, the first piezoelectric wafer, the inertia compensation mass block, the electrode sheet, and the second piezoelectric wafer are arranged in sequence along the axial direction. Simultaneously, the positive electrode of the first piezoelectric wafer is close to the insulating film, and the negative electrode is close to the inertia compensation mass block. The positive electrode of the second piezoelectric wafer is close to the electrode sheet, and the negative electrode is close to the housing, so that the first piezoelectric wafer and the second piezoelectric wafer are connected in series.

[0007] The force transmission block, the first piezoelectric wafer, the inertia compensation mass block, the electrode sheet and the second piezoelectric wafer form a crystal stack, and an insulating ring is provided between the side wall of the crystal stack and the inner wall of the component accommodating cavity;

[0008] The lead wire passes through the housing and the second piezoelectric wafer and is connected to the electrode sheet.

[0009] An optional solution is that the axial thickness of the inertia compensation mass block is three times the axial thickness of the force transmission block, and the axial thickness of the first piezoelectric chip is twice the axial thickness of the second piezoelectric chip.

[0010] An optional solution is that the diaphragm, force transmission block, and inertia compensation mass block are made of steel; the first piezoelectric chip and the second piezoelectric chip are made of quartz crystal; and the electrode sheet is made of copper.

[0011] An optional solution is that the insulating film is adhered to the lower surface of the diaphragm.

[0012] An optional solution is that the lead wire is connected to the electrode sheet by welding.

[0013] An optional solution is that the diaphragm is welded to the housing.

[0014] An optional solution is that the shell is assembled from an upper shell and a lower shell, a component accommodating cavity is provided in the upper shell, and the lead passes through the lower shell and the second piezoelectric chip to be connected to the electrode sheet.

[0015] The inertia compensation mass block in the crystal assembly structure of the pressure sensor of the present invention is used to compensate for the parasitic output caused by acceleration and has an inertia compensation function. The crystal assembly also includes two piezoelectric chips, which are connected in series to output a voltage signal. The small number of piezoelectric chips reduces the difficulty of assembly, has a small impact on the natural frequency of the sensor, and ensures the dynamic performance of the piezoelectric pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the cross-sectional structure of the explosion field piezoelectric pressure sensor of the present invention.

[0017] Figure 2 : This is the pressure output response of the piezoelectric pressure sensor in the explosion field according to the embodiment of the present invention. DETAILED DESCRIPTION

[0018] Unless otherwise specified, the terms and methods herein are understood by those skilled in the art or are implemented using existing methods.

[0019] The directional or orientation terms such as axial and downward described herein are consistent with those in the drawings of the specification. It should be noted that the drawings of the specification are intended to explain the present invention, and the solutions obtained by technicians in this field through equivalent transformations on the basis of the drawings are all within the scope of the disclosure of the present invention.

[0020] See also Figure 1 As shown, the explosion field piezoelectric pressure sensor of the present invention includes a housing, a component accommodating chamber is provided in the housing, a diaphragm 1 is provided at a sensing opening at an axial end of the component accommodating chamber, an insulating film 2, a force transmission block 3, a first piezoelectric chip 4, an inertia compensation mass block 5, an electrode sheet 6, and a second piezoelectric chip 7 are sequentially arranged in the accommodating chamber along the axial direction;

[0021] Wherein: the diaphragm 1 is fixed to, for example, a sensing opening at the axial end of the component accommodating cavity by welding; the insulating film 2 is adhered to the lower surface of the diaphragm 1 to isolate the positive charge generated by the first piezoelectric chip 4; the first piezoelectric chip 4 is a non-porous chip, and the second piezoelectric chip 7 is a chip with a hole for the lead 11 to penetrate and connect, for example, to the electrode sheet 6 by welding;

[0022] The first piezoelectric chip 4 and the second piezoelectric chip 7 are connected in series, that is, the positive electrode of the first piezoelectric chip 4 is close to the insulating film 2, and the negative electrode is close to the inertia compensation mass block 5, and the positive electrode of the second piezoelectric chip 7 is close to the electrode sheet 6, and the negative electrode is close to the shell or the inner wall of the accommodating cavity; because the first piezoelectric chip 4 and the second piezoelectric chip 7 are connected in series, the electrode sheet 6 outputs a voltage signal;

[0023] The force transmission block 3, the first piezoelectric chip 4, the inertia compensation mass block 5, the electrode sheet 6, and the second piezoelectric chip 7 form a crystal stack and are coaxially stacked in the accommodating cavity. An insulating ring 8 is provided between the side wall of the crystal stack and the inner wall of the accommodating cavity to ensure the insulation of the sensor;

[0024] The lead wire 11 passes through the housing and the second piezoelectric wafer and is welded to the electrode sheet 6 .

[0025] The working principle of the explosion field piezoelectric pressure sensor of the present invention is as follows:

[0026] When the shock wave pressure acts on the sensor, the shock wave pressure is transmitted in sequence through the diaphragm 1, the force transmission block 3, the first piezoelectric chip 4, the inertia compensation mass block 5, the electrode plate 6, and the second piezoelectric chip 7. Each structural component is affected by the shock wave pressure. The first piezoelectric chip 4 generates positive charges on the upper surface and negative charges on the lower surface. The second piezoelectric chip 7 also generates positive charges on the upper surface and negative charges on the lower surface. Since the first piezoelectric chip 4 and the second piezoelectric chip 7 are connected in series, the electrode plate 6 outputs a voltage signal proportional to the shock wave pressure and outputs it through the lead 11.

[0027] When the sensor is subjected to acceleration (especially acceleration in the same direction but opposite to the shock wave pressure), the entire sensor is subjected to force, namely, the diaphragm 1, force transmission block 3, first piezoelectric chip 4, inertia compensation mass block 5, electrode plate 6, and second piezoelectric chip 7 are all subjected to inertial force. At this time, the inertia compensation mass block 5 exerts opposing forces on the first piezoelectric chip 4 and the second piezoelectric chip 7, such as tensile stress on the first piezoelectric chip and compressive stress on the second piezoelectric chip; alternatively, compressive stress on the first piezoelectric chip and tensile stress on the second piezoelectric chip, causing the first piezoelectric chip 4 and the second piezoelectric chip 7 to generate opposite voltage signals, thereby compensating for the parasitic acceleration output signal.

[0028] To ensure that the inertia compensation mass 5 exerts opposing forces on the first and second piezoelectric wafers 4 and 7 when subjected to external acceleration, in a preferred embodiment, the axial structural dimensions or axial thickness ratios of the force transmission block 3, the inertia compensation mass 5, the first piezoelectric wafer 4, and the second piezoelectric wafer 7 can be optimized. For example, the axial thickness of the inertia compensation mass 5 is three times that of the force transmission block 3, and the axial thickness of the first piezoelectric wafer 4 is twice that of the second piezoelectric wafer 7.

[0029] In the specific solution, the shape and structure of the diaphragm 1, insulating film 2, force transmission block 3, first piezoelectric chip 4, inertia compensation mass block 5, electrode sheet 6, and second piezoelectric chip 7 are determined according to the sensor housing structure, and are commonly disc or cylindrical.

[0030] In a specific solution, the diaphragm 1, the force transmission block 3, and the inertia compensation mass block 5 can be made of high-strength steel; the first and second piezoelectric chips can be made of quartz crystal; and the electrode sheet 6 can be made of copper.

[0031] Example:

[0032] The shell of the explosion field piezoelectric pressure sensor of this embodiment is assembled by an upper shell 9 and a lower shell 10 (specifically, it can be assembled by welding), wherein a component accommodating cavity is provided in the upper shell; the inner diameter of the component accommodating cavity provided in the shell 9 is 3.9 mm, the axial thickness of the diaphragm 1 is 0.2 mm, the thickness of the insulating film 2 is 0.2 mm, the thickness of the force transmission block 3 is 0.5 mm, the thickness of the first piezoelectric chip 4 is 0.4 mm, the thickness of the inertia compensation mass block 5 is 1.5 mm, the thickness of the electrode sheet 6 is 0.1 mm, the thickness of the second piezoelectric chip 7 is 0.2 mm, and the cross-section of each component is circular.

[0033] In this embodiment, the diaphragm 1 , the force transmission block 3 , and the inertia compensation mass block 5 are made of maraging steel; the first and second piezoelectric wafers are made of quartz crystal; and the electrode sheet 6 is made of copper.

[0034] The finite element simulation method is used to simulate and analyze the sensor of this embodiment. The simulation conditions are: the sensor body is set as a fixed constraint, a pressure load of 0-1 MPa is applied in the vertical direction of the sensor diaphragm, and the voltage output signal of the electrode sheet is the output signal of the sensor. The pressure output response of the sensor of this embodiment is as follows: Figure 2 As shown in Figure 3, the results show that the pressure sensitivity of the sensor is 39.7V / MPa.

Claims

1. An explosion field piezoelectric pressure sensor, comprising a housing and a lead (11), wherein a component accommodating cavity is provided in the housing, characterized in that: An induction opening is provided at one axial end of the component accommodating cavity, and a diaphragm (1) is provided at the induction opening. An insulating film (2), a force transmission block (3), a first piezoelectric chip (4), an inertia compensation mass block (5), an electrode sheet (6) and a second piezoelectric chip (7) are installed in the component accommodating cavity, and the diaphragm, the insulating film, the force transmission block, the first piezoelectric chip, the inertia compensation mass block, the electrode sheet and the second piezoelectric chip are arranged in sequence along the axial direction; at the same time, the positive electrode of the first piezoelectric chip is close to the insulating film and the negative electrode is close to the inertia compensation mass block, and the positive electrode of the second piezoelectric chip is close to the electrode sheet and the negative electrode is close to the shell, so that the first piezoelectric chip and the second piezoelectric chip are connected in series; The force transmission block (3), the first piezoelectric chip (4), the inertia compensation mass block (5), the electrode sheet (6) and the second piezoelectric chip (7) form a crystal pile, and an insulating ring (8) is provided between the side wall of the crystal pile and the inner wall of the component accommodating cavity; The lead wire passes through the housing and the second piezoelectric wafer and is connected to the electrode sheet.

2. The explosion field piezoelectric pressure sensor according to claim 1, characterized in that: The axial thickness of the inertia compensation mass block (5) is three times the axial thickness of the force transmission block (3), and the axial thickness of the first piezoelectric chip (4) is twice the axial thickness of the second piezoelectric chip (7).

3. The explosion field piezoelectric pressure sensor according to claim 1, characterized in that: The diaphragm (1), the force transmission block (3) and the inertia compensation mass block (5) are made of steel; the first piezoelectric chip (4) and the second piezoelectric chip (7) are made of quartz crystal; and the electrode sheet (6) is made of copper.

4. The explosion field piezoelectric pressure sensor according to claim 1, characterized in that: The insulating film is bonded to the lower surface of the diaphragm.

5. The explosion field piezoelectric pressure sensor according to claim 1, characterized in that: The lead wire is connected to the electrode sheet by welding.

6. The explosion field piezoelectric pressure sensor according to claim 1, characterized in that: The diaphragm is welded to the shell.

7. The explosion field piezoelectric pressure sensor according to claim 1, characterized in that: The shell is assembled from an upper shell (9) and a lower shell (10); a component accommodating cavity is provided in the upper shell; the lead wire passes through the lower shell and the second piezoelectric chip and is connected to the electrode sheet.

Images