Differential vibration sensor

Abstract

The invention discloses a differential vibration sensor, and particularly relates to the technical field of sensors. The differential vibration sensor comprises a shell assembly and a base connected with the outside of the shell assembly, the static plate assembly is fixed in the shell assembly through a plurality of fixing screws; the two moving plate assemblies are symmetrically arranged on the upper side and the lower side of the static plate assembly respectively, and each moving plate assembly comprises a moving electrode layer; the two elastic bodies are arranged on the outer sides, back to the static plate assembly, of the two movable plate assemblies respectively; wherein the static plate assembly comprises a static electrode layer, the static electrode layer and the moving electrode layer are oppositely arranged, and a gap is formed between the static electrode layer and the moving electrode layer to form a triboelectric effect structure; a plurality of guide studs are further fixed to the static plate assembly, and a guide hole is formed in the movable plate assembly. The differential vibration sensor provided by the invention realizes self-power supply by using a triboelectric effect, and does not need an external power supply.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and more particularly to a differential vibration sensor. Background Technology

[0002] Vibration sensors play a crucial role in vibration monitoring, fault diagnosis, and intelligent operation and maintenance of mechanical equipment. Traditional vibration sensors mainly include piezoelectric and electromagnetic types. Piezoelectric sensors suffer from problems such as large temperature drift and poor low-frequency response, and typically require externally powered signal conditioning circuits. Electromagnetic sensors, on the other hand, are easily affected by complex electromagnetic environments.

[0003] Sensors based on triboelectric nanogenerators have attracted attention due to their advantages such as self-powered operation, high sensitivity, and low cost. However, existing triboelectric vibration sensors still have room for improvement in terms of structural stability, resistance to lateral interference, and measurement accuracy. For example, Chinese patent CN116592990A discloses a vibration sensor based on triboelectric nanogenerators, but in complex vibration environments, the moving part is prone to swaying in directions other than the measurement direction, leading to signal distortion and reduced measurement accuracy.

[0004] Therefore, developing a self-powered vibration sensor that can operate stably for a long time in complex environments, with high precision and strong anti-interference capabilities, is of great practical significance. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a differential vibration sensor with stable structure, strong anti-interference ability and high measurement accuracy. The differential vibration sensor utilizes the triboelectric effect to achieve self-powered operation and does not require an external power source.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A differential vibration sensor includes: a housing assembly and a base externally connected thereto; a stationary plate assembly fixed inside the housing assembly by multiple fixing screws; two moving plate assemblies symmetrically arranged on the upper and lower sides of the stationary plate assembly, each moving plate assembly including a moving electrode layer; two elastomers respectively disposed on the outer sides of the two moving plate assemblies opposite to the stationary plate assembly; wherein, the stationary plate assembly includes a static electrode layer, the static electrode layer and the moving electrode layer are disposed opposite to each other with a gap, forming a triboelectric effect structure; multiple guide studs are also fixed on the stationary plate assembly, and the moving plate assembly has guide holes, the guide studs passing through the guide holes and cooperating with the guide holes to restrict the movement of the moving plate assembly in a plane parallel to the stationary plate assembly.

[0008] Preferably, the guide studs include at least three and are evenly distributed on the stationary plate assembly. The guide studs extend outward from the upper and lower surfaces of the stationary plate assembly and pass through the guide holes on the upper and lower moving plate assemblies, respectively.

[0009] Preferably, the guide stud has a thread direction opposite to that of the fixing screw.

[0010] Preferably, it further includes a locking assembly that is threaded to the end of the guide stud and presses the elastomer against the moving plate assembly to provide an adjustable elastic preload.

[0011] Preferably, the moving plate assembly further includes a moving plate and a conductive layer, the conductive layer being fixed to the surface of the moving plate facing the stationary plate assembly, and the moving electrode layer being fixed to the conductive layer; and / or,

[0012] The stationary plate assembly also includes a stationary plate, and the stationary electrode layer is fixed on the upper and lower surfaces of the stationary plate.

[0013] Preferably, the conductive layer is electrically connected to a signal connector fixed on the housing assembly via a wire, for outputting the electrical signal generated by the triboelectric effect structure.

[0014] Preferably, both the base and the outer casing assembly are made of metal, together forming an electromagnetic shielding structure.

[0015] Preferably, it also includes a magnet assembly, which is fixed to the base and located below the overall sensor structure.

[0016] Preferably, the elastomer is made of silicone, EVA, foam, or rubber.

[0017] Preferably, the sensor comprises multiple alternating layers of moving plate assemblies and stationary plate assemblies.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) This invention utilizes the triboelectric effect to directly convert mechanical energy into electrical energy without the need for an external power source, thus fundamentally avoiding the noise introduced by the power line and realizing a truly self-powered sensing.

[0020] (2) By precisely matching the guide stud with the guide hole, the present invention strictly limits the movement of the moving plate assembly in the horizontal plane, ensuring that it vibrates only along the measurement direction (Z-axis), effectively eliminating signal crosstalk caused by multi-axis coupled motion, and significantly improving measurement accuracy.

[0021] (3) The differential structure of the present invention with symmetrical upper and lower parts outputs signals with opposite phases, which facilitates subsequent differential processing, effectively suppresses environmental common-mode noise, multiplies useful signals, and has a high signal-to-noise ratio.

[0022] (4) The guide stud of the present invention forms a stable multi-point support guide structure, and combined with the locking component with adjustable preload, the overall structure of the sensor is robust and impact resistant.

[0023] (5) The present invention adopts a combination design of elastomer and locking component, which provides good elastic support and preload adjustment function for moving plate assembly, improves the sensitivity and measurement range of sensor, and extends the service life of sensor.

[0024] (6) The metal casing of the present invention provides electromagnetic shielding and the magnet base is easy to install, making it very suitable for complex industrial sites. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 This is a three-dimensional structural cross-sectional view of the present invention.

[0027] Figure 3 This is a schematic diagram of the internal structure of the present invention.

[0028] Figure 4 This is a schematic diagram of the moving plate assembly of the present invention.

[0029] Figure 5 This is a schematic diagram of the still plate assembly of the present invention.

[0030] Figure 6 This is a schematic diagram of the housing assembly of the present invention.

[0031] The numbers in the diagram are: 1-base, 2-moving plate assembly, 21-moving plate, 22-conductive layer, 23-moving electrode layer, 3-stationary plate assembly, 31-stationary plate, 32-stationary electrode layer, 33-guide stud, 34-fixing screw, 4-elastomer, 5-locking assembly, 6-housing assembly, 61-housing, 62-signal connector, 7-magnet assembly. Detailed Implementation

[0032] 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.

[0033] Example 1

[0034] Reference Figures 1 to 6 This embodiment provides a differential vibration sensor, which achieves high-precision, self-powered vibration measurement through a differential structure and precise mechanical guidance.

[0035] The sensor includes a base 1, a moving plate assembly 2, a stationary plate assembly 3, an elastomer 4, a locking assembly 5, a housing assembly 6, and a magnet assembly 7.

[0036] The base 1 is preferably made of stainless steel in a disc shape. Its main function is to provide a mounting base for the entire sensor and together with the outer shell assembly 6, form an electromagnetic shielding shell to effectively isolate external electromagnetic interference.

[0037] The housing assembly 6 includes a housing 61 and a signal connector 62. The housing 61 is also made of metal (such as aluminum alloy) and is tightly connected to the base 1 by screws to form a closed cavity. The signal connector 62 (such as a BNC connector or aviation plug) is fixed through an opening on the housing 61 and sealed with a sealing ring. Its internal contacts are connected to wires for outputting electrical signals.

[0038] The stationary plate assembly 3 is fixedly mounted inside the housing 61 by a plurality of fixing screws 34. Specifically, the stationary plate assembly 3 includes a circular stationary plate 31, which is preferably made of aluminum alloy to reduce weight. An electrostatic electrode layer 32 is fixed to the upper and lower surfaces of the stationary plate 31 by adhesive bonding. The electrostatic electrode layer 32 is preferably made of polyimide (PI) film, serving as a triboelectric material that readily gains and loses electrons. Furthermore, the stationary plate 31 is machined with a plurality of evenly distributed countersunk holes, some of which are used to install guide studs 33, and others are used to pass through the fixing screws 34 to lock the entire stationary plate assembly 3 onto the housing 61. The guide studs 33 are made of stainless steel and extend vertically outward from the upper and lower surfaces of the stationary plate 31, with an extension length preferably of 15 mm.

[0039] There are two moving plate assemblies 2, both with identical structures, symmetrically arranged on the upper and lower sides of the stationary plate assembly 3. Each moving plate assembly 2 includes a circular moving plate 21, which is preferably made of PEEK (polyetheretherketone) insulating material. A conductive layer 22, which is copper foil tape, is attached to the surface of the moving plate 21 facing the stationary plate 31. A moving electrode layer 23 is fixed on the surface of the conductive layer 22, which is preferably made of PTFE (polytetrafluoroethylene) film, as another triboelectric material with a different triboelectric sequence than the PI film. Multiple guide holes are formed on the moving plate 21, and the positions of these guide holes correspond one-to-one with the guide studs 33 on the stationary plate assembly 3, so that the guide studs 33 can pass precisely through these guide holes.

[0040] The guide stud 33 and the guide hole on the moving plate assembly 2 are fitted with a small clearance, allowing the moving plate assembly 2 to slide freely along the axial direction (i.e., the Z-axis direction) of the guide stud 33, but its movement is strictly restricted to the plane parallel to the stationary plate 31 (i.e., the XY direction). This precise guiding mechanism ensures that the moving plate assembly 2 can only reciprocate along the Z-axis during vibration, avoiding signal interference caused by lateral swaying, thereby significantly improving the accuracy of vibration measurement.

[0041] The number of elastic bodies 4 is twice that of the guide studs 33, and they are respectively disposed on the outer side of the upper and lower moving plate assemblies 2, opposite to the stationary plate assembly 3. The elastic bodies 4 are preferably silicone gaskets with a thickness of 2 mm. The function of the elastic bodies 4 is to provide elastic restoring force for the moving plate assembly 2 and to determine the sensor's natural frequency and measurement range.

[0042] The locking assembly 5 includes a nut and a locking nut, which are threadedly connected to the end of a guide stud 33 extending beyond the moving plate assembly 2. By tightening the nut, a preload can be applied to the elastic body 4, thereby adjusting the initial force between the moving plate assembly 2 and the stationary plate assembly 3 and the stiffness of the system. The locking nut is used to prevent the nut from loosening under vibration. In this environment, the guide stud 33 has the functions of "guiding" and "bearing the preload".

[0043] The magnet assembly 7 is fixed to the center of the base 1 by a double-ended screw, and it includes a neodymium iron boron permanent magnet. The main function of the magnet assembly 7 is to facilitate the sensor to be attached to the surface of the ferromagnetic device for measurement, greatly improving the ease of installation.

[0044] Working principle:

[0045] During assembly, first, the stationary plate assembly 3 is fixed inside the housing 61 using fixing screws 34. Then, the guide holes of the upper and lower moving plate assemblies 2 are aligned with the guide studs 33 on the upper and lower sides, respectively, and inserted. Next, the elastomers 4 are fitted onto the guide studs 33 on both sides, and then the nuts of the locking assembly 5 are screwed in and adjusted to a suitable preload. Finally, the lead wires of the conductive layer 22 are soldered to the internal contacts of the signal connector 62, and the base 1 is placed on top to complete the assembly.

[0046] During operation, the sensor is attached to the device under test via the magnet assembly 7. When the device vibrates in the Z-axis direction, the entire sensor housing moves accordingly. Due to inertia, the moving plate assembly 2 will undergo relative displacement with respect to the stationary plate assembly 3, compressing or releasing the elastomer 4. During this process, the moving electrode layer 23 (PTFE) and the stationary electrode layer 32 (PI) periodically contact and separate. Based on the principle of contact-separation triboelectric nanogenerator, charges are generated on the contact surface, thereby generating an alternating induced electrical signal on the conductive layer 22. The electrical signal is output to an external acquisition device through the signal connector 62. Since the upper and lower moving plate assemblies 2 are symmetrical differential structures, their output signals are out of phase, allowing for differential processing to effectively suppress common-mode noise (such as temperature drift) and multiply the useful vibration signal, ultimately achieving high signal-to-noise ratio and high-precision vibration measurement.

[0047] Example 2

[0048] The main difference between this embodiment and Embodiment 1 lies in the selection of materials and some dimensions.

[0049] The base 1 is made of iron, with a diameter of 60mm and a thickness of 12mm.

[0050] The moving plate 21 is made of aluminum alloy with a thickness of 6mm; the moving electrode layer 23 is made of polyimide film.

[0051] The static electrode 31 is made of titanium alloy with a thickness of 10mm; the static electrode layer 32 is made of polyamide film.

[0052] The guide stud 33 and the retaining screw 34 are made of copper and have an extension length of 18mm. In particular, the guide stud 33 and the retaining screw 34 are screws with opposite thread directions. This cross-thread design can better resist the risk of loosening caused by vibration.

[0053] Elastomer 4 uses an EVA foam gasket with a thickness of 3mm.

[0054] The outer casing 61 is connected to the base 1 by welding to achieve better sealing.

[0055] This embodiment also possesses all the technical effects described in Embodiment 1, and adapts to possible special working conditions through different material combinations, including but not limited to more corrosive environments.

[0056] For those skilled in the art, the present invention is not limited to the details of the exemplary embodiments described above. Various modifications and substitutions can be made to the materials, shapes, and details of the components without departing from the principles and spirit of the invention, and all such modifications and substitutions should fall within the scope of protection defined by the claims of the present invention. Specifically:

[0057] The base 1 is not limited to stainless steel, but may also be made of other metal materials that provide good structural strength and electromagnetic shielding performance, including but not limited to iron, aluminum alloy, titanium alloy, etc.

[0058] The moving piece 21 and the stationary piece 31 have a wide range of material choices. They can be made of metal materials (such as iron, stainless steel, and aluminum alloy) as described in the embodiments, or they can be made of insulating or non-metallic materials to achieve specific properties, such as acrylic, PEEK, PVC, PTFE, and ceramics.

[0059] The moving electrode layer 23 and the stationary electrode layer 32 are triboelectric material pairs, and their materials can be selected from a variety of dielectric materials or metals. The moving electrode layer 23 can be selected from paper, PEEK, PVC, PTFE, etc.; the stationary electrode layer 32 can be selected from paper, PEEK, PVC, PTFE, and other materials that are paired with it in the triboelectric sequence.

[0060] In addition to copper foil tape, conductive layer 22 can also be made of other metal materials, such as nickel foil.

[0061] The elastomer 4 can be selected according to the required stiffness, damping and frequency response, and its material includes, but is not limited to, EVA, silicone, foam, rubber, or a spring when higher temperature resistance and linearity are required.

[0062] The materials of the guide stud 33, the fixing screw 34 and the locking assembly 5 (including the nut and the lock nut) can be selected according to the requirements of strength, rust prevention and cost. For example, iron, copper and stainless steel are all feasible options.

[0063] Furthermore, the "differential" structure described in this invention is not limited to two layers. It can be extended into a multi-layer structure by alternately stacking multiple moving plate components 2 and stationary plate components 3, depending on the requirements of signal output and sensitivity.

Claims

1. A differential vibration sensor, characterized in that, include: The outer casing assembly (6) and the base (1) connected to it externally; The stationary plate assembly (3) is fixed inside the housing assembly (6) by a plurality of fixing screws (34); Two moving plate assemblies (2) are symmetrically arranged on the upper and lower sides of the stationary plate assembly (3), and the moving plate assembly (2) includes a moving electrode layer (23). Two elastic bodies (4) are respectively disposed on the outer side of the two moving sheet assemblies (2) opposite to the stationary sheet assembly (3); The stationary plate assembly (3) includes a stationary electrode layer (32), which is disposed opposite to the moving electrode layer (23) and has a gap, forming a triboelectric effect structure. The stationary plate assembly (3) is also fixed with a plurality of guide studs (33), and the moving plate assembly (2) is provided with a guide hole. The guide studs (33) pass through the guide hole and cooperate with the guide hole to restrict the movement of the moving plate assembly (2) in a plane parallel to the stationary plate assembly (3).

2. The differential vibration sensor according to claim 1, characterized in that, The guide studs (33) include at least three and are evenly distributed on the stationary plate assembly (3). The guide studs (33) extend outward from the upper and lower surfaces of the stationary plate assembly (3) and pass through the guide holes on the upper and lower moving plate assemblies (2) respectively.

3. The differential vibration sensor according to claim 2, characterized in that, The guide stud (33) has the opposite thread direction to the fixing screw (34).

4. The differential vibration sensor according to claim 1, characterized in that, It also includes a locking assembly (5) which is threaded to the end of the guide stud (33) and presses the elastomer (4) onto the moving plate assembly (2) to provide an adjustable elastic preload.

5. The differential vibration sensor according to claim 1, characterized in that, The moving plate assembly (2) further includes a moving plate (21) and a conductive layer (22), the conductive layer (22) being fixed to the surface of the moving plate (21) facing the stationary plate assembly (3), and the moving electrode layer (23) being fixed to the conductive layer (22); and / or, the stationary plate assembly (3) further includes a stationary plate (31), the stationary electrode layer (32) being fixed to the upper and lower surfaces of the stationary plate (31).

6. The differential vibration sensor according to claim 5, characterized in that, The conductive layer (22) is electrically connected to a signal connector (62) fixed on the housing assembly (6) via a wire, for outputting the electrical signal generated by the triboelectric effect structure.

7. The differential vibration sensor according to claim 1, characterized in that, The base (1) and the outer shell assembly (6) are both made of metal and together form an electromagnetic shielding structure.

8. The differential vibration sensor according to claim 1, characterized in that, It also includes a magnet assembly (7), which is fixed to the base (1) and located below the overall structure of the sensor.

9. The differential vibration sensor according to claim 1, characterized in that, The elastomer (4) is made of silicone, EVA, foam or rubber.

10. The differential vibration sensor according to claim 1, characterized in that, The sensor includes multiple alternating layers of moving plate assembly (2) and stationary plate assembly (3).

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