Compression type high-temperature (300 DEG C) piezoelectric acceleration sensor

Abstract

The invention relates to the technical field of high-temperature vibration monitoring, and provides a novel compression type structure sensor aiming at the problems of sensitivity attenuation and insufficient thermal stability of a traditional piezoelectric sensor under the working condition of 200-300 DEG C. According to the device, monolithic PZT piezoelectric ceramic is adopted as a sensitive element, and the depolarization temperature is increased to 302 DEG C through a double-doping technology, which is obviously superior to that of similar materials. According to the structural design, the laminated layout of the lower pressing block, the mass block, the insulating sheet, the piezoelectric ceramic and the base is adopted, the insulating sheet is provided with a reserved circular groove and a wiring notch, and efficient lead-out of an electrode wire is achieved. Tests show that the sensor is low in charge sensitivity attenuation in an environment of 300 DEG C and high in inherent frequency. Through single-chip design and material modification, high-sensitivity vibration detection in a high-temperature environment is realized while the preparation process is simplified, and the sensor can be widely applied to the fields of aero-engine monitoring, new energy automobile thermal management and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a compression-type high-temperature acceleration sensor. Background Art

[0002] High-precision vibration monitoring technology is a core pillar for ensuring the reliability of high-end equipment throughout its lifecycle. In strategic areas such as thermal management of new energy vehicle powertrains, precision machining accuracy control for precision machine tools, and structural health monitoring of aircraft engines, real-time acquisition and analysis of vibration signals holds irreplaceable engineering value for condition-based maintenance (CBM) and closed-loop control of process quality. These typical applications generally face challenges in medium- to high-temperature operating environments of 200-300°C. Traditional piezoelectric vibration sensors, due to material limitations, face technical bottlenecks such as sensitivity attenuation, reduced signal-to-noise ratio, and insufficient thermal stability in high-temperature environments.

[0003] The core of high-temperature piezoelectric accelerometers lies in the temperature resistance and piezoelectric performance of the piezoelectric sensitive element, that is, the piezoelectric sheet. The piezoelectric sheet needs to maintain good piezoelectric performance at the required temperature. Although traditional PZT piezoelectric ceramics have excellent electromechanical coupling characteristics, their Curie temperature (T c =260-280℃) and depolarization inflection point (d 33 The PZT piezoelectric ceramics used in this patented piezoelectric sensitive element have achieved d 33 The temperature stability is greatly improved, and 100% of the initial piezoelectric response is still maintained at a high temperature of 302°C, meeting the application requirements of 300°C.

[0004] Furthermore, existing compression sensors mostly use ring-shaped piezoelectric discs, which are difficult to manufacture and often produce microcracks during processing, affecting device performance. This invention has designed a novel sensor structure using a monolithic and circular design, offering high sensitivity, a wide response range, and excellent temperature resistance, with a maximum operating temperature of 300°C. Summary of the Invention

[0005] The present invention provides a compression-type high-temperature piezoelectric acceleration sensor, which adopts high depolarization temperature PZT piezoelectric ceramics and a single-piece wafer design to prepare an acceleration sensor that can work stably at 300°C.

[0006] The sensor comprises a lower pressing block, a mass block, an upper insulating sheet, a sensitive element, a lower insulating sheet and a base.

[0007] Preferably, the pressing block is composed of a bolt column and a contact piece, and is located on the top of the sensor.

[0008] Preferably, the mass block is located between the lower pressing block and the upper insulating sheet, and is used to achieve acceleration measurement through inertial force conversion.

[0009] Preferably, the upper and lower insulating sheets are designed with a circular groove reserved in the middle and a wiring slot.

[0010] Preferably, the piezoelectric sensitive element is composed of a single double-doped PZT piezoelectric ceramic piece, which is placed in the circular groove of the lower insulating piece and fixed by the upper insulating piece.

[0011] From the above technical solution, it can be seen that the compression-type high-temperature (300°C) piezoelectric acceleration sensor described in the present invention has certain advantages, as shown in the following:

[0012] 1. The use of single-piece PZT piezoelectric ceramics reduces the cost of piezoelectric sensitive components.

[0013] 2. Using high-valent ion and low-valent ion dual-doped lead zirconate titanate ceramic sheets as piezoelectric sensitive elements effectively increases the operating temperature of the sensor.

[0014] 3. The entire interior adopts direct full contact surface design, which effectively increases the maximum contact area and natural frequency of the piezoelectric sensitive element. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0016] Attachment Figure 1 This is a schematic diagram of the structure of the piezoelectric accelerometer in Example 1.

[0017] Attachment Figure 2 This is the overall assembly diagram of the piezoelectric acceleration sensor in Example 1.

[0018] Attachment Figure 3 This is a diagram of the insulating sheet parts in Example 1.

[0019] Attachment Figure 4 This is the amplitude-frequency curve of the piezoelectric acceleration sensor in Example 1.

[0020] Attachment Figure 5 This is a diagram of the insulating sheet parts in Example 2.

[0021] Numbers in the figure: 1, lower pressure block; 2, mass block; 3, upper insulating sheet; 4, piezoelectric sensitive element; 5, lower insulating sheet; 6, base. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Example 1: The present invention proposes a compression-type high-temperature (300°C) piezoelectric acceleration sensor, comprising a lower pressing block, a mass block, an upper insulating sheet, a piezoelectric sensitive element based on modified lead zirconate titanate piezoelectric ceramics, a lower insulating sheet, and a base. The overall structure is shown in the attached Figure 1 , Attachment Figure 2 , pass the bolts on the lower pressure block through the shell and connect it to the pressure block, connect the mass block, upper insulating sheet, piezoelectric ceramic, lower insulating sheet to the base in turn, connect the base to the shell through the 4 screw holes at the bottom, and after fixing, screw on the pressure block to press down and fix the entire structure.

[0024] The insulating sheet is shown in the attached Figure 3 A large circular groove is designed on the insulating sheet to fix the piezoelectric ceramics, a small circular groove is designed on the large circular groove to place the solder joints on the piezoelectric ceramics, and a wire groove is reserved for the lead-out of the electrode wires.

[0025] The piezoelectric ceramics are modified PZT piezoelectric ceramics, the Curie temperature of which reaches 330° C. and the depolarization temperature of which reaches 302° C.

[0026] The piezoelectric sensitive element is made of piezoelectric ceramics. The electrode wires resistant to 300℃ are led out at the center of the positive and negative poles using 350℃ high-temperature solder, and the lower insulating sheet is placed in line with the position of the insulating sheet's circular groove and the wire groove, and then the upper insulating sheet is covered.

[0027] A high temperature test system was built to test the sensitivity of the piezoelectric accelerometer in the temperature range from room temperature to 300°C. The results are shown in the attached Figure 4 , frequency response test results of piezoelectric accelerometer at 300℃ high temperature.

[0028] Example 2: The difference from Example 1 is that the slot in the middle of the insulating sheet is a square slot design, see attached Figure 5 , using square piezoelectric ceramics.

[0029] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A design of a compression type high temperature (300℃) piezoelectric acceleration sensor, characterized by Simple structure and excellent performance.

2. The sensor according to claim 1 comprises a lower pressing block, a mass block, an upper insulating sheet, a sensitive element, a lower insulating sheet, and a base.

3. The pressing block according to claim 1 is composed of a bolt column and a contact piece and is located on the top of the sensor.

4. The mass block according to claim 1 is located between the lower pressing block and the upper insulating sheet, and is used to measure acceleration through inertial force conversion.

5. The upper and lower insulating sheets according to claim 1 are designed with a circular groove reserved in the middle and a wiring slot.

6. The piezoelectric sensitive element according to claim 1 is composed of a single piece of PZT-4 piezoelectric ceramic sheet, placed in the circular groove of the lower insulating sheet and fixed by the upper insulating sheet.

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