A piezoelectric accelerometer for measuring a vibration signal

Abstract

The utility model provides a piezoelectric accelerometer for measuring vibration signal relates to the field of vibration sensor, including piezoelectric ceramic ring, piezoelectric ceramic ring is along the radial polarization, is respectively pasted with upper electrode and lower electrode on the upper and lower surface of piezoelectric ceramic ring, and the electric field direction of upper electrode and lower electrode for applying alternating voltage is orthogonal with the polarization direction of piezoelectric ceramic ring alternating voltage;Mass ring, with piezoelectric ceramic ring concentric and cover piezoelectric ceramic ring outside, and the first insulating layer for blocking mass ring and piezoelectric ceramic ring electric connection is arranged between mass ring and piezoelectric ceramic ring;Cylindrical center fixed rod, insert in the inner ring of piezoelectric ceramic ring, and with piezoelectric ceramic ring forms the second insulating layer for blocking center fixed rod and piezoelectric ceramic ring electric connection.The piezoelectric ceramic ring and mass ring of annular composite structure are adopted in the application, and the alternating voltage of the electric field direction and the polarization direction orthogonal can excite d 15 Mode shear piezoelectric effect.

Description

Technical Field

[0001] This utility model relates to the field of vibration sensors, and in particular to a piezoelectric accelerometer for measuring vibration signals. Background Technology

[0002] Piezoelectric accelerometers, as core components in vibration measurement, have wide applications in industrial monitoring, aerospace, and other fields. Traditional structures typically employ a central compression or shear design, utilizing the d-axis of piezoelectric materials... 33 or d 31 The model achieves electromechanical conversion. Although this type of structure is technologically mature, it still has obvious limitations in practical applications.

[0003] Central compression accelerometers typically employ a sandwich structure of mass block-piezoelectric element-base, which inherently presents a trade-off between sensitivity and resonant frequency. Increasing sensitivity requires either increasing the mass block size or reducing system stiffness, but this leads to a decrease in resonant frequency, affecting high-frequency measurement capabilities. Furthermore, this structure is sensitive to base strain and is easily affected by deformation of the mounting surface, resulting in measurement errors.

[0004] Shear-type designs have mitigated the strain sensitivity issue of the base to some extent, but existing solutions often employ triangular central pillars or multi-layered stacked structures. These structures can lead to stress concentration when transmitting vibrational energy, potentially causing degradation of the piezoelectric material's performance over long-term operation. Furthermore, the complex mechanical structure increases manufacturing difficulty and cost, limiting its miniaturization potential.

[0005] In recent years, ring-structure accelerometers have provided a new approach to solving the above problems. However, existing designs mostly adopt axial polarization, which fails to fully utilize the advantages of the shear mode of piezoelectric materials, such as the stress concentration problem caused by triangular structures and multi-layer stacked structures. Utility Model Content

[0006] This invention provides a piezoelectric accelerometer for measuring vibration signals, the purpose of which is to fully utilize the advantages of axial polarization, reduce stress concentration, and extend the service life of the accelerometer.

[0007] To achieve the above objectives, embodiments of this utility model provide a piezoelectric accelerometer for measuring vibration signals, comprising:

[0008] A piezoelectric ceramic ring, wherein the piezoelectric ceramic ring is radially polarized, and an upper electrode and a lower electrode are respectively attached to the upper and lower surfaces of the piezoelectric ceramic ring;

[0009] A mass ring, concentric with the piezoelectric ceramic ring and sleeved outside the piezoelectric ceramic ring, is provided with a first insulating layer between the mass ring and the piezoelectric ceramic ring to prevent electrical connection between the mass ring and the piezoelectric ceramic ring;

[0010] A cylindrical central fixing rod is inserted into the inner ring of the piezoelectric ceramic ring, and together with the piezoelectric ceramic ring, forms a second insulating layer to prevent the central fixing rod from being electrically connected to the piezoelectric ceramic ring;

[0011] The electric field direction of the alternating voltage applied by the upper and lower electrodes is parallel to the axis of the central fixed rod.

[0012] Preferably, the first insulating layer and the second insulating layer are made of epoxy resin material. The first insulating layer is bonded to the piezoelectric ceramic ring and the mass ring, respectively, and the second insulating layer is bonded to the central fixing rod and the inner ring of the piezoelectric ceramic ring, respectively.

[0013] Preferably, the piezoelectric ceramic ring is bonded to the upper electrode and the lower electrode respectively through a conductive layer.

[0014] Preferably, the mass ring is a high-density metal with a density greater than or equal to 19 g / cm³.

[0015] Preferably, the high-density metal is a tungsten alloy.

[0016] Preferably, the central fixing rod is a rod made of metal.

[0017] The above-mentioned solution of this utility model has the following beneficial effects:

[0018] This application employs a ring-shaped composite structure of a piezoelectric ceramic ring and a mass ring. Applying an alternating voltage with an electric field direction orthogonal to the polarization direction can excite d 15 The shear piezoelectric effect of the mode. At the same time, the central fixing rod adopts a cylindrical structure, because its smooth sides can smoothly and continuously transmit the force, fundamentally avoiding the stress concentration problem inherent in conventional triangular central pillars.

[0019] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the present invention;

[0021] Figure 2 This is a schematic diagram of the polarization of a piezoelectric ceramic ring;

[0022] Figure 3 yes Figure 1 A sectional view.

[0023] [Explanation of Labels in the Attached Image]

[0024] 10-Piezoelectric ceramic ring, 20-Upper electrode, 30-Lower electrode, 40-Mass ring, 41-First insulating layer, 50-Central fixing rod, 51-Second insulating layer.

[0025] D-polarization direction. Detailed Implementation

[0026] To make the technical problems, technical solutions and advantages of this utility model clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0027] like Figure 1-3 As shown, where Figure 3 yes Figure 1 A sectional view, the axis of the central fixing rod 50 is... Figure 3 The cross-sections are coplanar. An embodiment of this utility model provides a piezoelectric accelerometer for measuring vibration signals, including a piezoelectric ceramic ring 10, a mass ring 40, and a central fixing rod 50. The piezoelectric ceramic ring 10 is annular, having concentric inner and outer rings. The piezoelectric ceramic ring 10 is radially polarized. An upper electrode 20 is attached to the upper surface of the piezoelectric ceramic ring 10, and a lower electrode 30 is attached to the lower surface of the piezoelectric ceramic ring 10. The upper electrode 20 and the lower electrode 30 are used to apply alternating voltage.

[0028] A mass ring 40, as described above, is also fitted around the outer edge of the piezoelectric ceramic ring 10. The mass ring 40 is concentrically arranged with the piezoelectric ceramic ring 10, and a first insulating layer 41 is provided between the mass ring 40 and the piezoelectric ceramic ring 10. The first insulating layer 41 is used to block the electrical connection between the mass ring 40 and the piezoelectric ceramic ring 10. It can be understood that the mass ring 40 is fitted around the outer edge of the composite structure formed by the piezoelectric ceramic ring 10, the upper electrode 20, and the lower electrode 30.

[0029] The aforementioned central fixing rod 50 is cylindrical and is inserted into the inner ring of the piezoelectric ceramic ring 10. A second insulating layer 51 is provided between the central fixing rod 50 and the piezoelectric ceramic ring 10, and the second insulating layer 51 blocks the electrical connection between the central fixing rod 50 and the piezoelectric ceramic ring 10.

[0030] In this application, the electric field direction of the alternating voltage is parallel to the axial direction of the central fixed rod 50. When the alternating voltage is applied, d is activated. 15 The shear piezoelectric coefficient generates axisymmetric shear strain. This strain produces different deformations on the upper and lower surfaces of the piezoelectric ceramic ring 10. For example, when the upper surface expands radially, the lower surface contracts radially, or when the upper surface contracts radially, the lower surface expands radially, forming the strain gradient required for bending deformation.

[0031] The shear strain generated by the piezoelectric ceramic ring 10 causes radial deformation in opposite directions on its upper and lower surfaces. Simultaneously, the mass ring 40 is positioned circumferentially around the piezoelectric ceramic ring 10, and this radial deformation is transmitted to the mass ring 40. The inertial mass of the mass ring 40 provides an acceleration-sensitive mechanism, and the shear strain of the piezoelectric ceramic ring 10 is effectively amplified through the mass inertia of the mass ring 40. This allows the radially polarized piezoelectric ceramic ring 10 to utilize its d... 15 The coefficient enables the conversion of shear strain to charge signal, significantly improving the charge output sensitivity of the sensor.

[0032] Correspondingly, non-contact optical measuring equipment can be used to measure bending deformation in this application. For example, measurement points are set on the upper surface of the piezoelectric ceramic ring 10 and the edge of the mass ring 40, respectively, to verify the displacement transfer effect by comparing the input strain and output displacement. An impedance analyzer is used to measure the system's resonance characteristics, including parameters such as resonant frequency, mechanical quality factor, and equivalent capacitance. Vibration testing is performed on a standard vibration table, measuring the axial sensitivity and the ratio of lateral sensitivity.

[0033] Preferably, in this application, both the first insulating layer 41 and the second insulating layer 51 are epoxy resin materials. Epoxy resin material is coated onto the outer surface of the piezoelectric ceramic ring 10, and then a mass ring 40 is fitted onto the outer edge of the piezoelectric ceramic ring 10. The piezoelectric ceramic ring 10 and the mass ring 40 are bonded together using epoxy resin material. The epoxy resin forms the first insulating layer 41 between the mass ring 40 and the piezoelectric ceramic ring 10. Because epoxy resin has insulating properties, the first insulating layer 41 can block the electrical connection between the piezoelectric ceramic ring 10 and the mass ring 40.

[0034] The second insulating layer 51 is disposed on the inner ring of the central fixing rod 50 and the piezoelectric ceramic ring 10 in the same manner.

[0035] Furthermore, in this application, the piezoelectric ceramic ring 10 is bonded to the upper electrode 20 and the lower electrode 30 respectively by conductive adhesive. The conductive adhesive is conductive, so conductive layers are formed between the piezoelectric ceramic ring 10 and the upper electrode 20 and between the piezoelectric ceramic ring 10 and the lower electrode 30, which achieve the effects of conduction and bonding.

[0036] In this embodiment, a conductive layer is used to achieve both bonding and conductivity, avoiding the need for pre-tightening the electrodes and piezoelectric ceramic ring 10 with bolts, thus preventing stress concentration around bolt holes and uneven pre-tightening force. Simultaneously, the conductive layer enables a more uniform stress distribution, avoiding stress concentration issues associated with multi-layered stacked structures.

[0037] This application extends the service life of the piezoelectric ceramic ring 10 by avoiding stress concentration, thus suppressing the initiation of microcracks and the degradation of its performance.

[0038] In this application, the mass ring 40 is made of a high-density metal, which refers to a metal with a density greater than or equal to 19 g / cm³. In this embodiment, the high-density metal is a tungsten alloy.

[0039] Preferably, the central fixing rod 50 is a rod made of metal.

[0040] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A piezoelectric accelerometer for measuring vibration signals, characterized in that, include: A piezoelectric ceramic ring (10) is radially polarized, and an upper electrode (20) and a lower electrode (30) are respectively attached to the upper and lower surfaces of the piezoelectric ceramic ring (10). A mass ring (40) is concentric with the piezoelectric ceramic ring (10) and sleeved outside the piezoelectric ceramic ring (10). A first insulating layer (41) is provided between the mass ring (40) and the piezoelectric ceramic ring (10) to prevent electrical connection between the mass ring (40) and the piezoelectric ceramic ring (10). A cylindrical central fixing rod (50) is inserted into the inner ring of the piezoelectric ceramic ring (10) and forms a second insulating layer (51) with the piezoelectric ceramic ring (10) to prevent the central fixing rod (50) from being electrically connected to the piezoelectric ceramic ring (10). The electric field direction of the alternating voltage applied by the upper electrode (20) and the lower electrode (30) is parallel to the axis of the central fixed rod (50).

2. The piezoelectric accelerometer for measuring vibration signals according to claim 1, characterized in that: The first insulating layer (41) and the second insulating layer (51) are made of epoxy resin. The first insulating layer (41) is bonded to the piezoelectric ceramic ring (10) and the mass ring (40) respectively. The second insulating layer (51) is bonded to the central fixing rod (50) and the inner ring of the piezoelectric ceramic ring (10) respectively.

3. The piezoelectric accelerometer for measuring vibration signals according to claim 1, characterized in that: The piezoelectric ceramic ring (10) is bonded to the upper electrode (20) and the lower electrode (30) respectively through a conductive layer.

4. The piezoelectric accelerometer for measuring vibration signals according to claim 1, characterized in that: The mass ring (40) is a high-density metal with a density greater than or equal to 19 g / cm³.

5. The piezoelectric accelerometer for measuring vibration signals according to claim 4, characterized in that: The high-density metal is a tungsten alloy.

6. The piezoelectric accelerometer for measuring vibration signals according to claim 1, characterized in that: The central fixing rod (50) is a rod made of metal.

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