A center-of-mass change bending-torsional coupling type piezoelectric energy harvesting device

Abstract

This invention discloses a variable center-of-mass bending-torsional coupling piezoelectric energy harvesting device, belonging to the field of piezoelectric material energy harvesting control. The device includes a mountain-shaped cantilever beam, piezoelectric ceramic plates, and two sets of variable center-of-mass mechanisms. The mountain-shaped cantilever beam is fixed to a support plate, and the piezoelectric ceramic plates are adhered to it. The two sets of variable center-of-mass mechanisms are respectively connected to both ends of the mountain-shaped cantilever beam, and rubber films are adhered to the opposite cavities of the two water tanks. External excitation causes the water in the water tanks to vibrate, and the centers of mass of the two water tanks shift in opposite directions, generating torque in opposite directions. This drives the mountain-shaped cantilever beam to undergo bending-torsional coupling vibration. The piezoelectric ceramic plates convert their mechanical energy into electrical energy through the positive piezoelectric effect and harvest it. This invention improves energy harvesting efficiency compared to traditional single bending type piezoelectric energy harvesting devices by utilizing the variable center-of-mass mechanism to generate bending-torsional coupling vibration and harvest energy. Simultaneously, by utilizing the center-of-mass shift caused by water vibration to induce bending-torsional coupling vibration in the mountain-shaped cantilever beam and harvest energy, it improves energy utilization.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric material energy harvesting and control, and specifically relates to a variable center-of-mass bending-torsional coupling type piezoelectric energy harvesting device. It utilizes the positive piezoelectric effect of a piezoelectric ceramic sheet to harvest electrical energy converted from the mechanical energy of the bending-torsional coupling vibration of a mountain-shaped cantilever beam caused by changes in the center of mass of a water storage tank. This improves upon the shortcomings of traditional piezoelectric energy harvesting devices, such as low energy harvesting efficiency and low energy utilization. It has broad application prospects in the field of piezoelectric energy harvesting. Background Technology

[0002] Currently, there are three main methods for converting mechanical energy into electrical energy: electrostatic energy harvesting, electromagnetic energy harvesting, and piezoelectric energy harvesting. However, electrostatic energy harvesting requires an initial voltage and has low energy density; electromagnetic energy harvesting has relatively low output power and is too bulky; while piezoelectric smart structures, as a type of mechanoelectric coupling structure based on the positive piezoelectric effect of piezoelectric materials, can flexibly realize the conversion between mechanical energy and electrical energy, thereby capturing mechanical energy from the external environment and having a wider range of applications.

[0003] In existing technologies, the most common piezoelectric energy harvester structure is the cantilever beam structure. Its working principle is based on the fact that the mechanical energy of bending vibration generated by the cantilever beam under external excitation can be converted into electrical energy and harvested through the positive piezoelectric effect of the piezoelectric ceramic sheet. However, the mechanical energy generated by the deformation vibration of a single bending cantilever beam structure is relatively small, and its energy harvesting efficiency and energy utilization rate are both low.

[0004] By inducing bending-torsional coupled vibrations in the cantilever beam through a variable center of mass mechanism, the mechanical energy generated by the deformation vibration of the cantilever beam is increased. Under the same external excitation, the energy harvesting efficiency is improved; at the same time, by utilizing the change in the center of mass of the water storage tank caused by water vibration, the energy utilization rate is improved. Summary of the Invention

[0005] The purpose of this invention is to provide a variable center of mass bending-torsional coupling piezoelectric energy harvesting device, aiming to improve the energy harvesting efficiency and energy utilization rate of traditional piezoelectric energy harvesting devices.

[0006] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0007] A piezoelectric energy harvesting device with variable center of mass bending-torsion coupling, characterized in that it includes: a piezoelectric energy harvesting section, a first variable center of mass mechanism, and a second variable center of mass mechanism;

[0008] The aforementioned variable center of mass bending-torsional coupling piezoelectric energy harvesting device is characterized in that: the piezoelectric energy harvesting part includes: a mountain-shaped cantilever beam 3 and a piezoelectric ceramic sheet 4; the mountain-shaped cantilever beam 3 has a mountain-shaped frame structure, and the piezoelectric ceramic sheet 4 is attached to the mountain-shaped cantilever beam 3; the fixed end of the mountain-shaped cantilever beam 3 is fixed to the support plate 1 by two sets of fixed end fasteners 2, the cantilever end is connected to a first variable center of mass mechanism, and at the same time, a second variable center of mass mechanism is connected to its concave part near the fixed end, the purpose of which is to make the mountain-shaped cantilever beam 3 undergo bending-torsional coupling vibration caused by the change of the center of mass of the two sets of variable center of mass mechanisms.

[0009] The aforementioned variable center of mass bending-torsional coupling piezoelectric energy harvesting device is characterized in that: the first variable center of mass mechanism includes: a mass block 5, a rectangular water tank 7, and a large rubber film 8; the rectangular water tank 7 is connected to the cantilever end of the mountain-shaped cantilever beam 3 through two sets of cantilever end fasteners 6; the two sets of mass blocks 5 are placed outside the two sets of cantilever end fasteners 6 to increase the vibration amplitude of the beam; the large rubber film 8 is pasted on the cavity opening of the rectangular water tank 7 to cause the center of mass of the water in the rectangular water tank 7 to shift along the cavity direction when the water vibrates under external excitation, thereby causing the mountain-shaped cantilever beam 3 to undergo bending-torsional coupling vibration.

[0010] The aforementioned variable center of mass bending-torsional coupling piezoelectric energy harvesting device is characterized in that: the second variable center of mass mechanism includes: a convex water tank 9, two sets of beam fasteners 10, two sets of L-shaped fasteners 11, and a small rubber film 12; the convex top of the convex water tank 9 is solid and is connected to the concave end of the mountain-shaped cantilever beam 3 near the fixed end through the two sets of beam fasteners 10 and the two sets of L-shaped fasteners 11; the cavity opening of the convex water tank 9 is opposite to the cavity opening of the rectangular water tank 7, and the small rubber film 12 is pasted on the cavity opening of the convex water tank 9. The purpose is to cause the center of mass of the convex water tank 9 to shift in the opposite direction to the center of mass of the rectangular water tank 7 when the water in the convex water tank 9 vibrates under external excitation, thereby causing a pair of opposite torques, so that the mountain-shaped cantilever beam 3 generates bending-torsional coupling vibration mechanical energy, which is converted into electrical energy through the positive piezoelectric effect of the piezoelectric ceramic sheet 4, thereby realizing the piezoelectric energy harvesting function. Attached Figure Description

[0011] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate the invention and are used to explain it, but do not constitute an undue limitation of the invention.

[0012] Figure 1 This is a schematic diagram of the overall appearance structure of a variable center of mass bending-torsion coupling piezoelectric energy harvesting device according to the present invention.

[0013] Figure 2 This is a schematic diagram of the vibration configuration under bending vibration mode of a piezoelectric energy harvesting device with variable center of mass bending-torsional coupling according to the present invention.

[0014] Figure 3 This is a schematic diagram of the vibration configuration under the bending-torsional coupling vibration mode of a variable center of mass piezoelectric energy harvesting device according to the present invention.

[0015] Figure 4 This is a schematic diagram of the first variable center of mass mechanism of a piezoelectric energy harvesting device of the present invention, which is a type of variable center of mass bending-torsion coupling.

[0016] Figure 5 This is a schematic diagram of the second centroid variable mechanism of a piezoelectric energy harvesting device of the present invention, which is a type of piezoelectric energy harvesting device with variable centroid bending-torsion coupling.

[0017] In the diagram: 1. Support plate; 2. Fixed end fastener; 3. Mountain-shaped cantilever beam; 4. Piezoelectric ceramic sheet; 5. Mass block; 6. Cantilever end fastener; 7. Rectangular water tank; 8. Large rubber membrane; 9. Convex water tank; 10. Beam fastener; 11. L-shaped fastener; 12. Small rubber membrane. Detailed Implementation

[0018] The following description, in conjunction with the accompanying drawings, further illustrates the detailed content of the present invention and its specific embodiments.

[0019] See Figure 1 As shown, a piezoelectric energy harvesting device with variable center of mass bending-torsion coupling includes a support plate 1, fixed end fasteners 2, a mountain-shaped cantilever beam 3, a piezoelectric ceramic sheet 4, a mass block 5, cantilever end fasteners 6, a rectangular water tank 7, a large rubber film 8, a convex water tank 9, beam fasteners 10, L-shaped fasteners 11, and a small rubber film 12. The fixed end of the mountain-shaped cantilever beam 3 is fixed to the support plate 1 by two sets of fixed end fasteners 2, and the piezoelectric ceramic sheet 4 is attached to the mountain-shaped cantilever beam 3 to form a piezoelectric energy harvesting part. The cantilever end of the mountain-shaped cantilever beam 3 is connected to the rectangular water tank 7 by two sets of cantilever end fasteners 6 to form a first variable center of mass mechanism. At the same time, it is connected to the convex water tank 9 near the fixed end concave part by two sets of beam fasteners 10 and two sets of L-shaped fasteners 11 to form a second variable center of mass mechanism.

[0020] See Figure 2 and Figure 3 As shown, the mountain-shaped cantilever beam 3 is a mountain-shaped frame structure. Its cantilever end and fixed end are respectively connected to a rectangular water tank 7 of the first variable center of mass mechanism and a convex water tank 9 of the second variable center of mass mechanism. A cavity is set in the negative X direction of the rectangular water tank 7 and a large rubber film 8 is attached thereto. At the same time, a cavity is set in the positive X direction of the convex water tank 9 and a small rubber film 12 is attached thereto. The purpose is to make the water in the rectangular water tank 7 and the convex water tank 9 vibrate under external excitation at a certain frequency, so that the center of mass of the two water tanks shifts to the negative X direction and the positive X direction respectively, and generates opposite torques in the clockwise and counterclockwise directions along the Y direction, so that the mountain-shaped cantilever beam 3 undergoes bending-torsional coupling vibration.

[0021] See Figure 4 As shown, the first variable center of mass mechanism includes: a mass block 5, a rectangular water tank 7, and a large rubber film 8; the rectangular water tank 7 is connected by two sets of cantilever end fasteners 6; the two sets of mass blocks 5 are placed outside the two sets of cantilever end fasteners 6 to increase the amplitude of beam vibration; the large rubber film 8 is pasted on the negative X-direction cavity of the rectangular water tank 7 to cause the center of mass to shift in the negative X-direction.

[0022] See Figure 5 As shown, the second variable center of mass mechanism includes: a convex water tank 9, two sets of beam fasteners 10, two sets of L-shaped fasteners 11, and a small rubber film 12; the top of the convex water tank 9 is solid and is connected to the recessed part of the mountain-shaped cantilever beam 3 near the fixed end through the two sets of beam fasteners 10 and the two sets of L-shaped fasteners 11; the cavity opening of the convex water tank 9 is on the opposite side to the cavity opening of the rectangular water tank 7, and the small rubber film 12 is pasted on the positive X-direction cavity opening of the convex water tank 9. The purpose is to make the center of mass of the convex water tank 9 shift in the positive X-direction when the water vibrates, thereby generating a torque in the opposite direction to the negative X-direction shift of the center of mass of the rectangular water tank 7, so as to realize the bending-torsional coupling vibration of the mountain-shaped cantilever beam 3.

[0023] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made to the present invention should be included within the scope of protection of the present invention.

Claims

1. A piezoelectric energy harvesting device with variable core bending-torsion coupling, characterized in that: The structure includes a support plate (1), a mountain-shaped cantilever beam (3), a piezoelectric ceramic sheet (4), a rectangular water tank (7), a large rubber film (8), a convex water tank (9), and a small rubber film (12). One end of the mountain-shaped cantilever beam (3) is fixed to the support plate (1), and the other end is connected to the rectangular water tank (7). At the same time, the convex water tank (9) is connected to the concave part near the fixed end. The piezoelectric ceramic sheet (4) is pasted on the mountain-shaped cantilever beam (3). The rectangular water tank (7) is positioned in the negative X direction. A cavity is opened and a large rubber film (8) is pasted on it. At the same time, a cavity is opened in the positive X direction of the convex water tank (9) and a small rubber film (12) is pasted on it. When an external excitation of a certain frequency is given, the water in the two water tanks vibrates, causing the center of mass of the rectangular water tank (7) to shift in the negative X direction and generate a clockwise torque in the Y direction. Meanwhile, the center of mass of the convex water tank (9) shifts in the positive X direction and generates a counterclockwise torque in the Y direction, causing the bending-torsional coupling vibration of the mountain-shaped cantilever beam (3) and capturing energy.

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