Molybdenum disulfide / PVDF composite film piezoelectric sensor and preparation method thereof

Abstract

The invention discloses a molybdenum disulfide / PVDF (polyvinylidene fluoride) composite film piezoelectric sensor and a preparation method thereof, and relates to the field of piezoelectric sensors, the molybdenum disulfide / PVDF composite film piezoelectric sensor comprises a shell, the top end of the shell is provided with a detection port, the shell is internally provided with a sensing mechanism, the sensing mechanism is connected with a wire, the bottom end of the shell is in threaded connection with a bottom cover, and the bottom cover is in threaded connection with the detection port. An extending end is arranged in the middle of the bottom end of the bottom cover, the extending end communicates with the interior of the bottom cover, an elastic protective sleeve is slidably arranged in the extending end, and when the electric wire is located in the elastic protective sleeve, the two conical protective sleeves can support the edges of the two ends of the interior of the electric wire and the elastic protective sleeve; the electric leakage phenomenon caused by the fact that the two ends in the elastic protection sleeve and the electric wire are bent is avoided, and meanwhile the elastic protection sleeve can prevent external dust from entering the interior to cause the blocking and accumulation phenomenon.

Description

Technical Field

[0001] The present invention relates to the field of piezoelectric sensors, and in particular to a molybdenum disulfide / PVDF composite film piezoelectric sensor and a preparation method thereof. Background Art

[0002] Piezoelectric sensor is a sensor based on piezoelectric effect, which uses the charge phenomenon generated by certain dielectric materials when subjected to external forces to measure non-electrical quantities. PVDF piezoelectric film is a new type of polymer piezoelectric sensor functional material, which has many advantages such as soft texture, light weight, high application sensitivity, wide frequency response range, strong flexibility, high sensitivity, strong impact resistance, small noise signal, small impact on the mechanical properties of the structure, high mechanical strength, good impedance matching, etc. With the deepening of research, it is more and more widely used in the measurement of force, acceleration, displacement and structural strain.

[0003] Existing piezoelectric sensors are generally connected to external devices through wires, which provide electrical energy to the piezoelectric elements to work. When the connection between the wires and the piezoelectric sensors is subjected to external forces, they are easily bent, causing the wires to be worn and broken, affecting safe use.

[0004] Therefore, it is necessary to propose a MoS2 / PVDF composite film piezoelectric sensor and a preparation method thereof to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a molybdenum disulfide / PVDF composite film piezoelectric sensor and a preparation method thereof, so as to solve the problem that the existing piezoelectric sensors are generally connected to external devices through wires, and the piezoelectric elements are provided with electric energy through the wires to work. When the connection between the wires and the piezoelectric sensors is subjected to external forces, they are easily bent, resulting in loss and breakage of the wires, affecting the safety of use.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a molybdenum disulfide / PVDF composite film piezoelectric sensor includes a shell, a detection port is opened at the top of the shell, a sensing mechanism is arranged inside the shell, the sensing mechanism is connected to an electric wire, the bottom end of the shell is threadedly connected to a bottom cover, a protruding end is arranged in the middle of the bottom end of the bottom cover, the protruding end is connected to the inside of the bottom cover, an elastic protective sleeve is slidably arranged in the protruding end, the electric wire protrudes out of the elastic protective sleeve, and conical sleeves are fixed at both ends of the elastic protective sleeve, the conical tips of the two conical sleeves are arranged opposite to each other, the electric wire passes through the middle of the two conical sleeves, and a spacing is left between the two conical sleeves, a plurality of airbags are distributed in the spacing, the plurality of airbags are filled with fire extinguishing dry powder, one side of the airbag is fixed on the inner wall of the elastic protective sleeve, and the other side of the airbag is attached to the outside of the electric wire.

[0007] Preferably, a fixing screw is provided on the outer side of the protruding end, and one end of the fixing screw is pressed tightly against the outer side of the elastic protective sleeve.

[0008] Preferably, a threaded opening is provided on the outer side of the bottom cover, the threaded opening cooperates with the bottom thread inside the shell, and a threaded hole is provided on the outer side of the protruding end for the end of the fixing screw to pass through.

[0009] Preferably, a protruding block is fixed on the inner wall of the shell, a groove is opened at the bottom end of the protruding block, a spring is arranged inside the groove, the bottom end of the spring is connected to an extending block, the extending block extends out of the groove, and a lower pressure plate is connected to the bottom of the extending end of the extending block, and the lower pressure plate is in contact with the top end of the bottom cover.

[0010] Preferably, the sensing mechanism includes an insulator, a piezoelectric element is arranged inside the insulator, piezoelectric films are arranged at the top and bottom ends of the piezoelectric element, one of the piezoelectric films at the top is close to the detection port, and a circuit is connected to the bottom end of the sensing mechanism, and the circuit is electrically connected to the wire.

[0011] Preferably, an outer side of the connection between the line and the wire is provided with an insulating protective sleeve, and a support frame is fixed between the outer side of the insulating protective sleeve and the inner wall of the shell.

[0012] Preferably, a layer of EVA cushion is fixed on the inner wall of the shell, and the shell is configured to be cylindrical.

[0013] Preferably, the protruding end and the bottom cover are integrally formed, a heat dissipation hole is provided at the bottom end of the bottom cover, the top end of the heat dissipation hole is connected to the interior of the shell, and a filter is provided inside the heat dissipation hole.

[0014] The present invention also discloses a method for preparing a molybdenum disulfide / PVDF composite film piezoelectric sensor, comprising the following steps:

[0015] The first step is to use PVDF as the substrate for the piezoelectric diaphragm, with a convex pressure-sensing microstructure array on the upper surface of the substrate and a concave groove structure on the lower surface of the substrate;

[0016] Step 2: The concave groove structure is filled with a piezoelectric filler, wherein the piezoelectric filler is molybdenum disulfide, and the piezoelectric filler is connected to a circuit;

[0017] The third step is to induce polarization of PVDF with layered molybdenum disulfide to promote the formation of β phase in PVDF, which can be synchronized with the composite material molding.

[0018] Technical effects and advantages of the present invention:

[0019] 1. Inducing polarization of PVDF with layered molybdenum disulfide promotes the formation of β phase in PVDF, which can be synchronized with the composite material molding and has high compatibility. At the same time, combining the good piezoelectric properties of PVDF with the good flexibility and mechanical processing properties of PVDF, it is expected to prepare a piezoelectric composite material with high performance, achieve high output of piezoelectric nanogenerators, and apply it to the field of sensing of small stresses.

[0020] 2. In the actual operation of the present invention, the elastic protective sleeve invention can protect the connection between the wire invention and the inner part of the shell invention. At the same time, the elastic protective sleeve invention can slide up and down in the protruding end invention, and the adjusted length can be fastened by the fixing screw invention, so as to adjust the protection length of the wire invention and improve the service life of the wire invention.

[0021] 3. Furthermore, when the electric wire invention is inside the elastic protective cover invention, the two conical protective cover inventions can support the edges of the electric wire invention and the inner ends of the elastic protective cover invention to prevent the inner ends of the elastic protective cover invention and the electric wire invention from bending, causing the edges to cut the electric wire invention and cause leakage. At the same time, the elastic protective cover invention can prevent external dust from entering the interior and causing blockage and accumulation.

[0022] 4. When the end of the fixing screw invention is pressed against the outside of the elastic protective sleeve invention to fix the position of the elastic protective sleeve invention, the extrusion force will also cause the elastic protective sleeve invention to bend and deform toward the wire invention, so that the inner wall of the elastic protective sleeve invention contacts the outside of the wire invention. At the same time, the wire invention can be limited to prevent the wire invention from moving.

[0023] 5. In addition, multiple airbag inventions can also be supported on the outside of the wire invention to prevent the wire invention from shaking in the elastic protective cover invention. When the outer skin of the wire invention ruptures and leaks electricity, causing fire and combustion, the flame or spark will melt the outer skin of the airbag invention, and the fire-extinguishing dry powder inside the airbag invention will leak out, which can extinguish the fire of the wire invention and improve the safety of use. At the same time, the filled fire-extinguishing dry powder can increase the supporting strength of the airbag invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of a molybdenum disulfide / PVDF composite film piezoelectric sensor of the present invention.

[0025] Figure 2 It is a structural schematic diagram of the threaded port of the present invention.

[0026] Figure 3 It is a schematic structural diagram of the piezoelectric element of the present invention.

[0027] Figure 4It is a schematic diagram of the structure of the airbag and the through hole of the present invention.

[0028] Figure 5 For the present invention Figure 4 Enlarged schematic diagram at point A in the middle.

[0029] In the figure: 1. outer shell; 2. detection port; 3. bottom cover; 4. protruding end; 5. elastic protective cover; 6. electric wire; 7. fixing screw; 8. threaded mouth; 9. piezoelectric diaphragm; 10. piezoelectric element; 11. insulator; 12. circuit; 13. EVA cushion; 14. support frame; 15. conical sleeve; 16. airbag; 17. through hole; 18. lower pressure plate; 19. protrusion; 20. groove; 21. spring; 22. protruding block. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clarify the technical solutions in the embodiments of the present invention; it is clearly described in detail. 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 creative work are within the scope of protection of the present invention.

[0031] The present invention provides Figure 1 - Figure 5 A molybdenum disulfide / PVDF composite film piezoelectric sensor shown includes a shell 1, a detection port 2 is opened at the top of the shell 1, a sensing mechanism is arranged inside the shell 1, and the sensing mechanism is connected to an electric wire 6. The sensing mechanism includes an insulator 11, and a piezoelectric element 10 is arranged inside the insulator 11. Piezoelectric diaphragms 9 are arranged on the upper and lower surfaces of the piezoelectric element 10, and the upper and lower piezoelectric diaphragms 9 are respectively covered with positive and negative electrodes.

[0032] One of the piezoelectric diaphragms 9 at the top is close to the detection port 2, and the bottom of the sensor mechanism is connected to a line 12, which is electrically connected to the wire 6. The piezoelectric diaphragm 9 close to the detection port 2 is bent toward the piezoelectric element 10 by an external force, and the piezoelectric element 10 is subjected to pressure or deformation, generating an electric potential signal output. By amplifying and processing the output signal, the value of the measured physical quantity can be obtained.

[0033] Specifically, a measurement conversion circuit and a charge amplifier are provided on the line 12. After the charge amplifier and the measurement circuit amplify and transform the impedance, they output an electric quantity proportional to the external force. Since this is the prior art, it will not be described in detail.

[0034] The bottom end of the shell 1 is threadedly connected to the bottom cover 3, and an extension end 4 is arranged in the middle of the bottom end of the bottom cover 3, and the extension end 4 is connected to the inside of the bottom cover 3. A threaded opening 8 is arranged on the outer side of the bottom cover 3, and the threaded opening 8 cooperates with the bottom thread inside the shell 1. The extension end 4 and the bottom cover 3 are integrally formed, and the extension end 4 and the bottom cover 3 are arranged in a T shape.

[0035] An elastic protective sleeve 5 is slidably arranged in the protruding end 4, the electric wire 6 protrudes from the elastic protective sleeve 5, and conical sleeves 15 are fixed at both ends of the elastic protective sleeve 5, the conical tips of the two conical sleeves 15 are arranged oppositely, the electric wire 6 passes through the middle of the two conical sleeves 15, and a spacing is left between the two conical sleeves 15, and multiple air bags 16 are distributed in the spacing, and the multiple air bags 16 are filled with fire extinguishing dry powder, one side of the air bag 16 is fixed on the inner wall of the elastic protective sleeve 5, and the other side of the air bag 16 is attached to the outer side of the electric wire 6. The elastic protective sleeve 5 is elastic and can be deformed by external force.

[0036] A fixing screw 7 is arranged on the outer side of the protruding end 4 , and one end of the fixing screw 7 is pressed tightly against the outer side of the elastic protective sleeve 5 .

[0037] In the actual operation of the present invention, the elastic protective cover 5 can protect the connection between the wire 6 and the inside of the shell 1. At the same time, the elastic protective cover 5 can slide up and down in the protruding end 4, and the adjusted length can be fastened by the fixing screw 7, so that the length of the protection of the wire 6 can be adjusted to improve the service life of the wire 5.

[0038] Furthermore, when the wire 6 is inside the elastic protective cover 5, the two conical protective covers 5 can support the edges of the wire 6 and the two ends of the elastic protective cover 5 to prevent the two ends inside the elastic protective cover 5 and the wire 6 from bending, causing the edges to cut the wire 6 and cause leakage. At the same time, the elastic protective cover 5 can prevent external dust from entering the interior and causing blockage and accumulation.

[0039] When the end of the fixing screw 7 is pressed against the outside of the elastic protective sleeve 5 to fix the position of the elastic protective sleeve 5, the extrusion force will also cause the elastic protective sleeve 5 to bend and deform toward the wire 6, so that the inner wall of the elastic protective sleeve 5 contacts the outside of the wire 6, and at the same time, the wire 6 can be limited to prevent it from moving.

[0040] In addition, multiple airbags 16 can also be supported on the outside of the wire 6 to prevent the wire 6 from shaking in the elastic protective cover 5. When the outer skin of the wire 6 breaks and leakage occurs, causing a fire, the flame or spark will melt the outer skin of the airbag 16, and the fire extinguishing dry powder inside the airbag 16 will leak out, which can extinguish the fire of the wire 6 and improve the safety of use. At the same time, the filled fire extinguishing dry powder can increase the supporting strength of the airbag 16.

[0041] A threaded hole is provided on the outer side of the protruding end 4 for the end of the fixing screw 7 to pass through.

[0042] A protruding block 19 is fixed on the inner wall of the shell 1, and a groove 20 is opened at the bottom end of the protruding block 19. A spring 21 is arranged inside the groove 20. The bottom end of the spring 21 is connected to a protruding block 22. The protruding block 22 protrudes out of the groove 20, and the bottom of the protruding end of the protruding block 22 is connected to a lower pressure plate 18, which abuts against the top of the bottom cover 3.

[0043] In the actual operation of the present invention, the bottom cover 3 and the outer shell 1 can be disassembled to facilitate personnel to replace and repair the internal structure.

[0044] At the same time, when the bottom cover 3 is rotated and threadedly installed inside the shell 1, the top of the bottom cover 3 will contact the lower pressure plate 18, and as the bottom cover 3 rotates and rises, the protruding block 22 will retract into the groove 20, and the pressure-reducing spring 21. Due to the elastic force of the spring 21, a certain height is always left between the threaded opening 8 on the outside of the bottom cover 3 and the thread inside the shell 1, so as to avoid the bottom cover 3 being locked or the thread slipping caused by excessive rotation.

[0045] An insulating protective sleeve is provided on the outer side of the connection between the line 12 and the wire 6 , and a support frame 14 is fixed between the outer side of the insulating protective sleeve and the inner wall of the housing 1 .

[0046] A layer of EVA cushion 13 is fixed on the inner wall of the shell 1 . The shell 1 is configured to be cylindrical. When the entire device falls, the EVA cushion 13 can absorb the impact and improve the safety of the internal structure of the shell 1 .

[0047] A heat dissipation hole 23 is provided at the bottom end of the bottom cover 3 , the top end of the heat dissipation hole 23 is communicated with the interior of the housing 1 , and a filter is provided inside the heat dissipation hole 23 to facilitate the dissipation of internal heat.

[0048] The present invention also discloses a method for preparing a molybdenum disulfide / PVDF composite film piezoelectric sensor, comprising the following steps:

[0049] S1. The piezoelectric diaphragm 9 uses PVDF as a substrate, and a protruding pressure-sensing microstructure array is provided on the upper surface of the substrate, and a concave groove structure is provided on the lower surface of the substrate. At the same time, PVDF, as a new type of polymer piezoelectric sensor functional material, has many advantages such as soft texture, light weight, high application sensitivity, wide frequency response range, strong flexibility, high sensitivity, strong impact resistance, small noise signal, little influence on the mechanical properties of the structure, high mechanical strength, and good impedance matching.

[0050] S2. The concave groove structure is filled with a piezoelectric filler, which is molybdenum disulfide. The piezoelectric filler is connected to the line 12. Molybdenum disulfide has a high piezoelectric coefficient, so it can generate more charges and has better sensitivity.

[0051] S3. Use layered molybdenum disulfide to induce polarization of PVDF and promote the formation of β phase in PVDF. It can be synchronized with the composite material molding and has high compatibility.

[0052] At the same time, the good piezoelectric properties of PVDF are combined with the good flexibility and mechanical processing properties of PVDF in order to prepare a piezoelectric composite material with high performance, achieve high output of piezoelectric nanogenerators, and apply it to the field of sensing of small stresses.

Claims

1. A molybdenum disulfide / PVDF composite film piezoelectric sensor, comprising a housing (1), characterized in that: The top of the housing (1) is provided with a detection port (2), the interior of the housing (1) is provided with a sensor mechanism, the sensor mechanism is connected to an electric wire (6), the bottom end of the housing (1) is threadedly connected to a bottom cover (3), a protruding end (4) is provided in the middle of the bottom end of the bottom cover (3), the protruding end (4) is connected to the interior of the bottom cover (3), an elastic protective cover (5) is slidably provided in the protruding end (4), the electric wire (6) protrudes from the elastic protective cover (5), and the elastic protective cover (5) is provided in a manner that allows the electric wire (6) to extend out of the elastic protective cover (5). Conical sleeves (15) are fixed at both ends of the inner part of the sheath (5), and the conical tips of the two conical sleeves (15) are arranged opposite to each other. The electric wire (6) passes through the middle of the two conical sleeves (15), and a spacing is left between the two conical sleeves (15). A plurality of air bags (16) are distributed in the spacing, and the plurality of air bags (16) are filled with fire extinguishing dry powder. One side of the air bag (16) is fixed on the inner wall of the elastic protective sleeve (5), and the other side of the air bag (16) is attached to the outer side of the electric wire (6).

2. The molybdenum disulfide / PVDF composite film piezoelectric sensor according to claim 1, characterized in that: A fixing screw (7) is arranged on the outer side of the protruding end (4), and one end of the fixing screw (7) is pressed tightly against the outer side of the elastic protective sleeve (5).

3. The molybdenum disulfide / PVDF composite film piezoelectric sensor according to claim 1, characterized in that: The outer side of the bottom cover (3) is provided with a threaded opening (8), the threaded opening (8) and the bottom thread inside the outer shell (1) are matched, and the outer side of the protruding end (4) is provided with a threaded hole for the end of the fixing screw (7) to pass through.

4. The molybdenum disulfide / PVDF composite film piezoelectric sensor according to claim 1, characterized in that: A protruding block (19) is fixed on the inner wall of the shell (1), a groove (20) is provided at the bottom end of the protruding block (19), a spring (21) is arranged inside the groove (20), the bottom end of the spring (21) is connected to a protruding block (22), the protruding block (22) protrudes out of the groove (20), and the bottom of the protruding end of the protruding block (22) is connected to a lower pressure plate (18), and the lower pressure plate (18) abuts against the top end of the bottom cover (3).

5. The molybdenum disulfide / PVDF composite film piezoelectric sensor according to claim 1, characterized in that: The sensing mechanism comprises an insulator (11), a piezoelectric element (10) is arranged inside the insulator (11), and piezoelectric films (9) are arranged on the upper surface and the lower surface of the piezoelectric element (10), wherein one of the piezoelectric films (9) located at the upper side is close to the detection port (2), and a circuit (12) is connected to the bottom end of the sensing mechanism, and the circuit (12) is electrically connected to the electric wire (6).

6. The molybdenum disulfide / PVDF composite film piezoelectric sensor according to claim 5, characterized in that: An insulating protective sleeve is provided on the outer side of the connection between the line (12) and the wire (6), and a support frame (14) is fixed between the outer side of the insulating protective sleeve and the inner wall of the outer shell (1).

7. The molybdenum disulfide / PVDF composite film piezoelectric sensor according to claim 1, characterized in that: A layer of EVA cushion (13) is fixed on the inner wall of the outer shell (1), and the outer shell (1) is configured in a cylindrical shape.

8. The molybdenum disulfide / PVDF composite film piezoelectric sensor according to claim 1, characterized in that: The protruding end (4) and the bottom cover (3) are integrally formed, a heat dissipation hole (23) is provided at the bottom end of the bottom cover (3), the top end of the heat dissipation hole (23) is connected to the interior of the housing (1), and a filter is provided inside the heat dissipation hole (23).

9. A method for preparing a MoS2 / PVDF composite film piezoelectric sensor, comprising a MoS2 / PVDF composite film piezoelectric sensor as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1, the piezoelectric diaphragm (9) uses PVDF as a substrate, a protruding pressure sensing microstructure array is provided on the upper surface of the substrate, and a concave groove structure is provided on the lower surface of the substrate; S2, the concave groove structure is filled with a piezoelectric filler, the piezoelectric filler is molybdenum disulfide, and the piezoelectric filler is connected to the circuit (12); S3, using layered molybdenum disulfide to induce polarization of PVDF, promoting the formation of β phase in PVDF, and synchronized with the composite material molding.

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