Differential electrostatic vibration sensor

Abstract

The utility model discloses a differential electrostatic vibration sensor, specifically relates to sensor technical field. Differential electrostatic vibration sensor, include: base, lower static piece subassembly is fixed on the base, moving piece subassembly, at least one elastomer provides elastic support for moving piece subassembly, makes it can vibrate relative to lower static piece subassembly, upper static piece subassembly is set in moving piece subassembly top, locking subassembly is used for the lower static piece subassembly, moving piece subassembly, elastomer and upper static piece subassembly are pressed tightly and provide pre -tightening force for elastomer, shell subassembly is sealedly connected with the base, is equipped with signal connector on shell subassembly, wherein, at least one surface of moving piece subassembly is equipped with conducting layer, and is electrically connected with signal connector through wire. The utility model provides differential electrostatic vibration sensor does not need external power supply, has high measuring accuracy, long life and is suitable for the advantage in harsh environment.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to a differential electrostatic vibration sensor. Background Technology

[0002] Vibration sensors play an important role in industrial production, mechanical equipment monitoring, geological exploration, and other fields. Although traditional capacitive vibration sensors have advantages such as high sensitivity and strong resistance to electromagnetic interference, they still have problems such as requiring an external power supply, being prone to failure in high temperature and humidity environments, having a limited lifespan, and being difficult to miniaturize.

[0003] In existing technologies, such as the self-powered vibration sensor disclosed in patent CN116380232A, the measurement accuracy is reduced due to susceptibility to electromagnetic interference; the capacitive sensor disclosed in patent CN112629569A requires optimization in the structural design of its sensing element in terms of accuracy and stability. Therefore, there is an urgent need for a vibration sensor solution that requires no external power supply, has high accuracy, long lifespan, and strong environmental adaptability. Utility Model Content

[0004] In view of the above situation and to overcome the defects of the prior art, this utility model provides a differential electrostatic vibration sensor that does not require an external power supply, has high measurement accuracy, long life and is suitable for harsh environments.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A differential electrostatic vibration sensor includes: a base; a lower stationary plate assembly fixed to the base; a moving plate assembly; an upper stationary plate assembly disposed above the moving plate assembly; at least one elastic body providing elastic support for the moving plate assembly, enabling it to vibrate relative to the lower and upper stationary plate assemblies; a locking assembly for pressing the lower stationary plate assembly, the moving plate assembly, the elastic body, and the upper stationary plate assembly together and providing a preload force to the elastic body; and a housing assembly sealed to the base, the housing assembly having a signal connector; wherein at least one surface of the moving plate assembly has a conductive layer and is electrically connected to the signal connector via a wire; the surfaces of the lower and / or upper stationary plate assemblies facing the moving plate assembly are each provided with an electrostatic electrode layer; when the moving plate assembly vibrates, an electrical signal is generated between its conductive layer and the electrostatic electrode layer through electrostatic induction.

[0007] Preferably, there are two elastomers, which are respectively disposed on the upper and lower sides of the moving plate assembly; the lower stationary plate assembly, the first elastomer, the moving plate assembly, the second elastomer, and the upper stationary plate assembly are stacked sequentially from bottom to top.

[0008] Preferably, the lower stationary plate assembly and the upper stationary plate assembly are respectively provided with a lower stationary electrode layer and an upper stationary electrode layer to form a differential structure.

[0009] Preferably, the moving plate assembly includes a moving plate and conductive layers disposed on its upper and lower surfaces, and a moving electrode layer is further disposed on the outer surface of the conductive layer.

[0010] Preferably, the static electrode layer and / or the dynamic electrode layer are made of an insulating material that can generate electricity through friction, preferably paper, PEEK, PVC or PTFE.

[0011] Preferably, the locking assembly includes a plurality of first guide screws, a plurality of second guide screws, and a plurality of nuts; the first and second guide screws are both fixed to the lower stationary plate assembly and pass through through holes in the moving plate assembly, the elastomer, and the upper stationary plate assembly in sequence; the nuts are screwed onto the ends of the first and second guide screws to provide clamping force.

[0012] Preferably, the first guide screw and the second guide screw have opposite thread directions and are distributed alternately on the lower stationary plate assembly.

[0013] Preferably, the elastomer is made of EVA, silicone, foam, rubber, or a metal spring.

[0014] Preferably, it also includes a magnet assembly connected to the base for adsorbing and fixing the sensor to the surface of the object being measured.

[0015] Preferably, the differential electrostatic vibration sensor has a multi-layer structure, comprising multiple moving plate assemblies, multiple lower stationary plate assemblies, and multiple upper stationary plate assemblies arranged in alternating layers, with adjacent layers separated by an elastomer.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) Mechanical vibration energy is directly converted into electrical signals through the principle of electrostatic induction, without the need for external power supply, thus realizing self-powered power supply and expanding the passive application scenarios.

[0018] (2) The differential structure of the upper and lower stationary plate components effectively amplifies the output signal and suppresses common-mode interference such as temperature drift, which significantly improves the measurement accuracy and reliability.

[0019] (3) The structure is simple and compact. Through the design of locking components and elastomers, the stability and vibration sensitivity of the structure are guaranteed. It is easy to achieve miniaturization and has a long service life.

[0020] (4) The dynamic and static electrode layers can be made of high-performance electret materials, which have good electromagnetic interference resistance and environmental adaptability.

[0021] (5) Output performance can be further improved through multi-layer stacking or surface microstructure design, which is highly flexible. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0023] Figure 2 This is a cross-sectional structural diagram of the present invention.

[0024] Figure 3 This is a schematic diagram of the internal structure of this utility model.

[0025] Figure 4 This is a schematic diagram of the lower stationary plate assembly of this utility model.

[0026] Figure 5 This is a schematic diagram of the moving plate assembly of this utility model.

[0027] Figure 6 This is a schematic diagram of the upper stationary plate assembly of this utility model.

[0028] Figure 7 This is a schematic diagram of the outer shell assembly of this utility model.

[0029] The corresponding names of the reference numerals in the attached drawings are as follows: 1-base, 2-lower stationary plate assembly, 21-lower stationary plate, 22-lower stationary electrode layer, 23-first guide screw, 24-second guide screw, 3-moving plate assembly, 31-moving plate, 32-conductive layer, 33-moving electrode layer, 4-elastic body, 5-upper stationary plate assembly, 51-upper stationary plate, 52-upper stationary electrode layer, 6-locking assembly, 7-housing assembly, 71-housing, 72-signal connector, 8-magnet assembly. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0031] Example 1:

[0032] See Figure 1-7 The differential electrostatic vibration sensor provided by the present invention includes a base 1, a lower stationary plate assembly 2, a moving plate assembly 3, an elastomer 4, an upper stationary plate assembly 5, a locking assembly 6, a housing assembly 7, and a magnet assembly 8.

[0033] The base 1 is made of 304 stainless steel and is cylindrical in shape with dimensions of 42mm × 21mm. The central area of ​​the base 1 has a groove for installing the lower stationary plate assembly 2, and the edges have steps and sealing grooves for connecting the outer shell assembly 7.

[0034] The lower stationary plate assembly 2 is fixed to the groove of the base 1 with epoxy resin adhesive. The lower stationary plate assembly 2 includes a lower stationary plate 21, a lower stationary electrode layer 22, a first guide screw 23, and a second guide screw 24. The lower stationary plate 21 is made of polytetrafluoroethylene (PTFE) sheet with a thickness of 0.5 mm to provide good insulation and mechanical strength. The lower stationary electrode layer 22 is a 0.1 mm thick PTFE film, which is uniformly attached to the upper surface of the lower stationary plate 21 with adhesive. The four first guide screws 23 and the four second guide screws 24 are all M3 stainless steel screws, evenly distributed around the circumference and vertically fixed in the countersunk holes of the lower stationary plate 21, with their screw portions extending upward. Among them, the first guide screws 23 have right-hand threads, and the second guide screws 24 have left-hand threads, and the two are arranged in a cross-alternating pattern on the lower stationary plate 21.

[0035] The moving plate assembly 3 is disposed above the lower stationary plate assembly 2. The moving plate assembly 3 includes a moving plate 31, a conductive layer 32, and a moving electrode layer 33. The moving plate 31 is an aluminum alloy disc with a thickness of 0.3 mm. The conductive layer 32 can be implemented in various ways. As a preferred embodiment, a 0.1 mm thick copper adhesive tape is used, which is tightly bonded to the upper and lower surfaces of the moving plate 31 using conductive adhesive. As a better alternative, the conductive layer 32 can be formed by coating the surface of the moving plate 31 with conductive silver paste. The thickness of this conductive silver paste coating is approximately 0.05 mm, and the conductivity of the conductive silver paste is ≥5 × 10⁻⁶. 5 With a strength of S / cm and a high temperature resistance of ≥200℃, it can form a uniform and strongly adherent conductive path. The moving electrode layer 33 is a 0.1mm thick PTFE film, which is applied to the outer surfaces of the upper and lower conductive layers 32 using an adhesive. Thus, the moving piece assembly 3 forms a five-layer composite structure from top to bottom: moving electrode layer 33, conductive layer 32, moving piece 31, conductive layer 32, and moving electrode layer 33.

[0036] Two elastic bodies 4 are used, both being silicone gaskets with a thickness of 1 mm and an outer diameter matching that of the moving plate 31. The first elastic body 4 is pressed and fixed between the lower stationary electrode layer 22 of the lower stationary plate assembly 2 and the lower surface moving electrode layer 33 of the moving plate assembly 3. The second elastic body 4 is pressed and fixed between the upper surface moving electrode layer 33 of the moving plate assembly 3 and the upper stationary plate assembly 5. That is, the lower stationary plate assembly 2, the first elastic body 4, the moving plate assembly 3, the second elastic body 4, and the upper stationary plate assembly 5 are stacked sequentially from bottom to top. The two elastic bodies 4 together provide symmetrical elastic support for the moving plate assembly 3, allowing it to vibrate freely in the vertical direction.

[0037] The upper stationary plate assembly 5 is disposed above the second elastic body 4. The upper stationary plate assembly 5 includes an upper stationary plate 51 and an upper stationary electrode layer 52. The upper stationary plate 51 is made of PTFE sheet with a thickness of 0.5 mm. The upper stationary electrode layer 52 is a PTFE film with a thickness of 0.1 mm, which is uniformly attached to the lower surface of the upper stationary plate 51 by an adhesive. Thus, both the lower stationary plate assembly 2 and the upper stationary plate assembly 5 are provided with stationary electrode layers, which, together with the middle moving plate assembly 3, constitute a highly sensitive differential sensing structure.

[0038] The locking assembly 6 includes multiple first guide screws 23, multiple second guide screws 24, and multiple stainless steel nuts. The first guide screws 23 and second guide screws 24 pass sequentially through corresponding through holes in the lower stationary plate 21, the first elastic body 4, the moving plate 31, the second elastic body 4, and the upper stationary plate 51, after which the nuts are screwed onto the threaded ends of the guide screws. Tightening the nuts provides preload to the upper and lower elastic bodies 4.

[0039] The housing assembly 7 includes a housing 71 and a signal connector 72. The housing 71 is made of aluminum alloy, and its lower end is bonded to the base 1 with a ring of epoxy resin sealant to form a sealed cavity. The signal connector 72 is a gold finger pin that is inserted through a hole in the side wall of the housing 71 and sealed with a rubber sealing ring. The conductive layer 32 of the moving plate assembly 3 is electrically connected to the inner end of the signal connector 72 through an extremely fine silver-plated copper wire. When the conductive layer 32 is copper tape, it is soldered using low-temperature soldering; when the conductive layer 32 is a conductive silver paste coating, it can be directly crimped using its own conductive adhesion, or bonded using conductive adhesive.

[0040] The magnet assembly 8 includes a neodymium iron boron magnet and a double-ended screw, which connects to the center of the bottom of the base 1 to magnetically attach the sensor to the surface of the ferrous object being measured. The magnet assembly 8 allows for quick installation and removal of the entire sensor without the need for drilling holes in the equipment.

[0041] Before assembly, the electret layer (which may be a moving electrode layer and / or upper and lower static electrode layers) needs to be pre-electretized, i.e., charged on the material surface is injected and stored. Electret methods include corona discharge, triboelectric discharge, and electron injection, with corona discharge being the most common. Corona discharge generates charged ions through tip discharge, which are then captured by the electret. The operating environment must be dry and clean to ensure the stability of the stored charge in the electret.

[0042] Working principle:

[0043] When the sensor vibrates with the object being measured, the moving plate assembly 3 undergoes a slight displacement relative to the upper and lower stationary plate assemblies due to inertia, causing a dynamic change in the spacing between the moving electrode layer 33 and the lower and upper stationary electrode layers 22 and 52. Because of the static charge on the surface of the electret layer, this spacing change induces a change in charge on the conductive layer 32 of the moving plate assembly 3 through electrostatic induction, thus generating an alternating electrical signal. This signal is transmitted to the signal connector 72 for output via a wire. Due to the use of a symmetrical differential structure, when the moving plate moves upward, the signal from the decrease in capacitance of the upper stationary plate and the signal from the increase in capacitance of the lower stationary plate are superimposed, effectively amplifying the output and suppressing common-mode interference caused by environmental factors such as temperature, significantly improving the signal-to-noise ratio and measurement accuracy. With the above structure, the sensor provided in this embodiment can achieve high-precision measurement with a measurement range of 0.01Hz-14kHz, a response time of less than 100ms, and is suitable for a wide temperature range of -50℃ to 80℃.

[0044] Example 2:

[0045] In another embodiment, the present invention can be simplified to a single-sided sensing structure to reduce costs. In this embodiment, only one elastic body 4 is provided, which is disposed between the moving plate assembly 3 and the lower stationary plate assembly 2. The upper stationary plate assembly 5 may not have the upper stationary electrode layer 52, and may only serve as a mechanical limit and structural support. Alternatively, the upper stationary plate assembly 5 may only have the upper stationary electrode layer 52, while the lower stationary plate assembly 2 may not have it. This simplified structure can still achieve the basic function of vibration sensing.

[0046] Example 3:

[0047] This application can be extended to a multi-layer structure to improve electrical signal output. In a specific example, the sensor adopts a stacked structure of "stationary plate assembly - moving plate assembly - stationary plate assembly - moving plate assembly - stationary plate assembly", that is, it includes two moving plate assemblies 3 and three stationary plate assemblies, with the layers separated by an elastic body 4. The conductive layers 32 of multiple moving plate assemblies 3 can be connected in parallel to the signal connector 72. This structure can approximately double the output charge, significantly improving the sensitivity of the sensor.

[0048] Example 4:

[0049] On the surfaces of the moving electrode layer 33 and / or the lower static electrode layer (22) and the upper static electrode layer (52), microstructures at the micrometer or nanometer scale are fabricated. These microstructures can be, but are not limited to, arrayed protrusions, pits, wrinkles, or composite structures. Periodic pyramidal, cylindrical, or grooved microstructures can be formed on the PTFE film surface through laser etching, chemical etching, or molding processes. The microstructures increase the effective frictional contact area and electrostatic induction area between the moving electrode layer 33 and the lower static electrode layer (22) and the upper static electrode layer (52). When the sensor vibrates, the more intense contact separation behavior and the more effective changes in electric field lines at the microscale can induce more static charge, thereby significantly enhancing the output electrical signal. By setting microstructures, sensitivity can be improved without changing the basic size of the sensor and the external circuitry, making it particularly suitable for applications that detect weak vibration signals.

[0050] Example 5:

[0051] The static and dynamic electrode layers can also be made of polyetheretherketone (PEEK) or polyvinyl chloride (PVC) film. The elastomer 4 can also be replaced with a metal spring or polyurethane foam. The base 1 and the outer shell 71 can also be injection molded from engineering plastics such as PPS to meet specific requirements.

Claims

1. A differential electrostatic vibration sensor, characterized in that, include: Base (1); The lower stationary plate assembly (2) is fixed on the base (1); Moving plate assembly (3); Upper stationary plate assembly (5), disposed above the moving plate assembly (3); At least one elastomer (4) provides elastic support for the moving plate assembly (3) so that it can vibrate relative to the lower stationary plate assembly (2) and the upper stationary plate assembly (5); Locking assembly (6) is used to press the lower stationary plate assembly (2), the moving plate assembly (3), the elastomer (4) and the upper stationary plate assembly (5) together and to provide preload force to the elastomer (4); The housing assembly (7) is sealed to the base (1), and the housing assembly (7) is provided with a signal connector (72). The moving plate assembly (3) has at least one surface provided with a conductive layer (32) and is electrically connected to the signal connector (72) via a wire; The surfaces of the lower stationary plate assembly (2) and / or the upper stationary plate assembly (5) facing the moving plate assembly (3) are provided with a static electrode layer; When the moving plate assembly (3) vibrates, its conductive layer (32) and the static electrode layer generate an electrical signal through electrostatic induction.

2. The differential electrostatic vibration sensor according to claim 1, characterized in that, The number of the elastic body (4) is two, which are respectively disposed on the upper and lower sides of the moving plate assembly (3); the lower stationary plate assembly (2), the first elastic body (4), the moving plate assembly (3), the second elastic body (4), and the upper stationary plate assembly (5) are stacked in sequence from bottom to top.

3. The differential electrostatic vibration sensor according to claim 1 or 2, characterized in that, The lower stationary plate assembly (2) and the upper stationary plate assembly (5) are respectively provided with a lower stationary electrode layer (22) and an upper stationary electrode layer (52) to form a differential structure.

4. The differential electrostatic vibration sensor according to claim 1, characterized in that, The moving plate assembly (3) includes a moving plate (31) and a conductive layer (32) disposed on its upper and lower surfaces. The outer surface of the conductive layer (32) is also provided with a moving electrode layer (33).

5. The differential electrostatic vibration sensor according to claim 4, characterized in that, The static electrode layer and / or the dynamic electrode layer (33) are made of an insulating material that can generate electricity through friction, such as paper, PEEK, PVC or PTFE.

6. The differential electrostatic vibration sensor according to claim 1, characterized in that, The locking assembly (6) includes a plurality of first guide screws (23), a plurality of second guide screws (24) and a plurality of nuts; the first guide screws (23) and the second guide screws (24) are both fixed on the lower stationary plate assembly (2) and pass through the through holes on the moving plate assembly (3), the elastomer (4) and the upper stationary plate assembly (5) in sequence; the nuts are screwed into the ends of the first guide screws (23) and the second guide screws (24) to provide clamping force.

7. The differential electrostatic vibration sensor according to claim 6, characterized in that, The first guide screw (23) and the second guide screw (24) have opposite thread directions and are interspersed on the lower stationary plate assembly (2).

8. The differential electrostatic vibration sensor according to claim 1, characterized in that, The material of the elastomer (4) is EVA, silicone, foam, rubber or metal spring.

9. The differential electrostatic vibration sensor according to claim 1, characterized in that, It also includes a magnet assembly (8), which is connected to the base (1) and is used to adsorb and fix the sensor to the surface of the object being measured.

10. The differential electrostatic vibration sensor according to claim 1, characterized in that, The differential electrostatic vibration sensor has a multi-layer structure, comprising multiple moving plate assemblies (3), multiple lower stationary plate assemblies (2), and multiple upper stationary plate assemblies (5) arranged in alternating layers, with adjacent layers separated by an elastic body (4).

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