A bidirectional vibration piezoelectric energy-harvesting device

Abstract

The application provides a bidirectional vibration piezoelectric energy capturing device, and belongs to the technical field of environmental vibration energy collection. The piezoelectric energy capturing device comprises a piezoelectric energy capturing module, and the piezoelectric energy capturing module comprises a cantilever beam, a mass block, a piezoelectric energy capturing unit, a fixed frame and a positioning block. The cantilever beam comprises a cross beam and a longitudinal beam; the cross beam and the longitudinal beam are connected to form an inverted L-shaped structure; the mass block is fixed at the free end of the cross beam; the longitudinal beam divides the inner part of the fixed frame into two accommodation spaces, and one piezoelectric energy capturing unit is assembled in each accommodation space; and the free end of the longitudinal beam is hinged to the fixed frame. The bidirectional vibration piezoelectric energy capturing device provided in the embodiment of the application combines the L-shaped cantilever beam with the end mass block, so that the piezoelectric energy capturing unit with an amplification frame forms a power system by means of the lever amplification effect, and the integrated collection of multi-directional vibration energy is realized, and the environmental adaptability and the energy conversion efficiency can be significantly improved.

Description

Technical Field

[0001] This invention relates to the field of environmental vibration energy harvesting technology, and more specifically, to a bidirectional vibration piezoelectric energy harvesting device. Background Technology

[0002] With the rapid development of science and technology, wireless sensors are increasingly being used in structural health monitoring and environmental condition sensing (such as in buildings, transportation, forests, deserts, and oceans). However, most existing wireless sensors rely on batteries for power. Their limited lifespan, high maintenance costs, and the environmental pollution caused by discarded batteries, coupled with the inaccessibility of manual replacement in certain scenarios, make a long-term, stable, and environmentally friendly energy supply a key bottleneck restricting their large-scale deployment. Therefore, obtaining sustainable electricity from environmental energy sources is considered an important technological path to replace traditional battery power.

[0003] It is worth noting that vibration energy, a renewable and clean energy source widely distributed in monitoring environments (e.g., the vibrations generated by vehicles or trains in tracks, bridges, and tunnels), is currently unused, resulting in resource waste. If efficient energy harvesting technologies could be employed to convert this energy into electrical energy and store it, it could provide a long-term power supply for wireless sensor networks, significantly reducing the frequency of manual inspections and maintenance costs. However, existing piezoelectric energy harvesting technologies mostly focus on a single vibration direction, and the energy harvesters suffer from low output efficiency and poor adaptability. Existing multi-directional energy harvesting devices generally face problems such as complex structures and insufficient conversion efficiency, making it difficult to fully utilize the electromechanical conversion characteristics of piezoelectric materials. Summary of the Invention

[0004] To address the technical problems of complex structure and low electromechanical conversion efficiency of existing multi-directional energy harvesting devices, the present invention aims to provide a bidirectional vibration piezoelectric energy harvesting device to overcome the bottlenecks of existing technologies that are sensitive to vibration direction and have limited energy conversion efficiency, thereby providing an efficient solution for autonomous power supply of wireless sensor networks.

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] This invention provides a bidirectional vibration piezoelectric energy harvesting device, including a piezoelectric energy harvesting module, wherein the piezoelectric energy harvesting module includes: a cantilever beam, a mass block, a piezoelectric energy harvesting unit, a fixed frame, and a positioning block;

[0007] The cantilever beam has an L-shaped structure, and the mass block is fixed to the free end of the crossbeam of the cantilever beam. The mass block is used to transfer the vibration energy of the external environment to the cantilever beam; the cantilever beam is a rigid body.

[0008] The fixed frame has an open end, and the free end of the longitudinal beam of the cantilever beam extends into the fixed frame from the open end; the longitudinal beam divides the interior of the fixed frame into two identical accommodating spaces, and each accommodating space is equipped with one of the piezoelectric energy harvesting units.

[0009] The free end of the longitudinal beam is hinged to the fixed frame. Each piezoelectric energy harvesting unit is fixedly connected to the longitudinal beam via a positioning block. The longitudinal beam forms a lever structure with the hinge point as the fulcrum and the positioning block. The longitudinal beam amplifies and transmits the vibration force transmitted by the mass block to the positioning block through the lever effect. The positioning block transmits the amplified force to the piezoelectric energy harvesting unit, so that the piezoelectric energy harvesting unit vibrates with the cantilever beam. The piezoelectric energy harvesting unit converts environmental vibration energy into electrical energy through the piezoelectric effect. The piezoelectric energy harvesting unit transmits the electrical energy through a wire.

[0010] Optionally, the piezoelectric energy harvesting unit includes: a piezoelectric stack assembly and a force amplification frame;

[0011] The force amplification frame includes: a first force-bearing beam, a second force-bearing beam, and two connecting beams; the first force-bearing beam, the second force-bearing beam, and the two connecting beams are connected to each other to form a frame structure; the first force-bearing beam and the second force-bearing beam are arranged opposite to each other; the first force-bearing beam is fixedly connected to the longitudinal beam through a positioning block; the second force-bearing beam is connected to the fixed frame through a positioning block.

[0012] The piezoelectric stack assembly is installed within the force amplification frame, and both ends of the piezoelectric stack assembly are connected to two connecting beams respectively.

[0013] Optionally, the first load-bearing beam and the second load-bearing beam are respectively arched, the arch tops of the first load-bearing beam and the second load-bearing beam are respectively connected to the positioning block, and the arch feet of the first load-bearing beam and the second load-bearing beam are respectively connected to the connecting beam.

[0014] Optionally, the connecting beam has a boss on one side within the force amplification frame, and the surface of the boss has a mounting groove; both ends of the piezoelectric stack assembly are respectively placed in the two mounting grooves.

[0015] Optionally, the piezoelectric stack assembly includes: a piezoelectric stack and a fixing block;

[0016] The piezoelectric stack includes a piezoelectric substrate and a conductive sheet; the piezoelectric substrate and the conductive sheet are stacked alternately to form an integral structure; both ends of the piezoelectric stack are connected to a fixing block through an adhesive layer, and the fixing block is placed in the corresponding mounting groove.

[0017] Optionally, the piezoelectric stack assembly further includes: an insulating layer;

[0018] The insulating layer is disposed between the piezoelectric stack and the fixing block; the insulating layer is connected to the piezoelectric stack and the fixing block respectively through an adhesive layer.

[0019] Optionally, the fixed frame includes: two right-angled J-shaped frames; each right-angled J-shaped frame includes: a short plate, a long plate, and a bottom plate; the short plate, long plate, and bottom plate are connected to each other to form a J-shaped structure with an open end, and the short plate and long plate are arranged opposite to each other; the two right-angled J-shaped frames are symmetrically arranged and the outer surfaces of the short plates of the two right-angled J-shaped frames are fitted together; the longitudinal beam is hinged to the short plate.

[0020] Optionally, the bidirectional vibratory piezoelectric energy harvesting device further includes: a hinge; the hinge includes: a first hinge plate, a second hinge plate, and a rotating shaft; the first and second hinge plates are respectively sleeved on the rotating shaft; the rotating shaft is disposed on the top of the two short plates, and the axis of the rotating shaft extends along the thickness direction of the right-angled J-shaped frame; the first hinge plate is inserted between the outer sides of the two short plates and the first hinge plate is fixed on the two short plates, and the second hinge plate is installed on the side of the longitudinal beam; the second force-bearing beam is connected to the long plate through a positioning block.

[0021] Optionally, the thickness of the piezoelectric substrate is less than 3 mm, and the number of piezoelectric substrates is not less than 15.

[0022] Compared with the prior art, the technical solution provided by this invention has at least the following beneficial effects:

[0023] The bidirectional vibration piezoelectric energy harvesting device provided in this invention utilizes the geometric configuration and dynamic response characteristics of an L-shaped cantilever beam to synchronously couple the vertical and horizontal vibration energy generated by the mass block into the horizontal input of the piezoelectric energy harvesting unit. This achieves integrated collection of multi-directional vibration energy and, with the help of the lever amplification effect, significantly improves environmental adaptability and energy conversion efficiency, overcoming the technical bottlenecks of traditional devices' sensitivity to vibration direction and low energy utilization. This vibration piezoelectric energy harvesting device can be widely applied in complex transportation infrastructure scenarios such as railway bridges, tunnels, and subways, enabling free deployment and stable operation. By efficiently collecting multi-directional environmental vibration energy and converting it into electrical energy, this device can provide a continuous and reliable energy supply for IoT terminal devices such as structural health monitoring systems and ecological environment monitoring networks, demonstrating significant technical practicality and application prospects. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a bidirectional vibration piezoelectric energy harvesting device according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a piezoelectric energy harvesting module according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the connection structure between a cantilever beam and a mass block according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of a piezoelectric energy harvesting unit according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of a force amplification frame according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of a right-angled J-shaped frame according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of a hinge member according to an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of a box-type outer frame according to an embodiment of the present invention;

[0033] Figure 9 This is a schematic diagram of a lever structure formed by a longitudinal beam and a mounting block according to an embodiment of the present invention.

[0034] [Figure Labels]

[0035] 1-Cantilever beam; 11-Horizontal beam; 12-Longitudinal beam;

[0036] 2-Mass block;

[0037] 3-Piezoelectric energy harvesting unit: 31-Piezoelectric stack assembly; 311-Piezoelectric stack; 3111-Piezoelectric substrate; 3112-Conductive sheet; 312-Fixing block; 32-Force amplification frame; 321-First force bearing beam; 322-Second force bearing beam; 323-Connecting beam; 3231-Boss; 3231a-Mounting groove;

[0038] 4a - Accommodation space; 41 - Right-angled J-shaped frame; 411 - Long board; 412 - Short board;

[0039] 5-Location block;

[0040] 6-Hinge; 61-First hinge plate; 62-Second hinge plate; 63-Shaft;

[0041] 7-Box-type outer frame. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0043] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0044] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0045] It is understood that the meanings of “on”, “above”, and “above” in this invention should be interpreted in the broadest manner, such that “on” means not only “directly on” something, but also includes the meaning of being “on” something with an intervening feature or layer, and that “above” or “above” means not only “on” something, but also includes the meaning of being “on” something without an intervening feature or layer.

[0046] Furthermore, spatially related terms such as “below,” “under,” “lower,” “above,” and “upper” are used herein for convenience to describe the relationship of one element or feature to one or more other elements or features, as illustrated in the accompanying drawings. Spatially related terms are intended to cover different orientations in the use or operation of the device other than those depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially related descriptive terms used herein can be interpreted similarly.

[0047] Figure 1 This is a schematic diagram of the structure of a bidirectional vibration piezoelectric energy harvesting device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a piezoelectric energy harvesting module according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the connection structure between a cantilever beam and a mass block according to an embodiment of the present invention; see reference. Figure 1-3 This invention provides a bidirectional vibration piezoelectric energy harvesting device, which includes a piezoelectric energy harvesting module. The piezoelectric energy harvesting module includes a cantilever beam 1, a mass block 2, a piezoelectric energy harvesting unit 3, a fixed frame, and a positioning block 5. The cantilever beam 1 includes a crossbeam 11 and a longitudinal beam 12. The crossbeam 11 and the longitudinal beam 12 are connected to form an inverted L-shaped structure. The mass block 2 is fixed to the free end of the crossbeam 11 and is used to transfer environmental vibration energy to the cantilever beam 1. The fixed frame has an open end, and the free end of the longitudinal beam 12 extends into the fixed frame from the open end. The longitudinal beam 12 divides the interior of the fixed frame into two... Each of the four identical accommodating spaces 4a contains one piezoelectric energy harvesting unit 3. The free end of the longitudinal beam 12 is hinged to the fixed frame, and each piezoelectric energy harvesting unit 3 is fixedly connected to the longitudinal beam 12 via a positioning block 5. The longitudinal beam 12 forms a lever structure with the hinge point as the fulcrum and the positioning block 5. The longitudinal beam 12 amplifies and transmits the vibration force transmitted by the mass block 2 to the positioning block 5 through the lever effect. The positioning block 5 transmits the amplified force to the piezoelectric energy harvesting unit 3, so that the piezoelectric energy harvesting unit 3 vibrates with the cantilever beam. The piezoelectric energy harvesting unit 3 converts environmental vibration energy into electrical energy through the piezoelectric effect, and transmits the electrical energy through a wire.

[0048] The cantilever beam 1 adopts an L-shaped structure, consisting of a horizontal crossbeam 11 and a vertical longitudinal beam 12 rigidly connected together. Both can be made of rigid plate-like materials. The free end of the crossbeam 11 can be fixed with a mass block 2 through pre-drilled mounting holes, and the free end is hinged to the fixed frame to allow free swinging. The cantilever beam 1 is a rigid body, and its material includes, but is not limited to, stainless steel, aluminum alloy, silicon carbide, ceramic, or rigid polycarbonate plastic.

[0049] Mass 2, located at the free end of crossbeam 11, generates inertial force during vibration. The right-angle structure of cantilever beam 1 converts both vertical and horizontal vibrations into horizontal oscillations, driving longitudinal beam 12 to compress the piezoelectric energy harvesting units 3 on both sides, achieving synchronous energy harvesting from vertical and horizontal vibrations. Mass 2 can be designed in various shapes, such as cubes, cuboids, or trapezoidal prisms. By changing its mass, mass 2 can alter the natural frequency of the piezoelectric energy harvesting unit 3, enabling it to match resonance conditions at different frequency bands under environmental vibration excitation, thereby achieving efficient and integrated collection of multi-frequency vibration energy.

[0050] The piezoelectric energy harvesting unit 3 can be a piezoelectric energy harvester, which can convert environmental vibration energy into electrical energy by generating an electric charge when subjected to tensile or compressive stress based on the piezoelectric effect. Two piezoelectric energy harvesting units 3 are used, symmetrically installed on both sides of the longitudinal beam 12 via positioning blocks 5, forming a lever mechanism with the hinge point as the fulcrum O. For example... Figure 9 As shown, the fulcrum O and the positioning block 5 form a resistance arm L2, and the right-angle connection point between the fulcrum and the longitudinal beam 12 forms a power arm L1. The longitudinal beam 12 is subjected to a horizontal force F1 transmitted from the mass block 2 in the right direction (or left), and the positioning block 5 is subjected to a horizontal resistance F2 applied by the longitudinal beam 12 in the left direction (or right). According to the lever principle, the following formula exists: F1·L1=F2·L2. Since L1>L2, then F2>F1. That is, the vibration force of the longitudinal beam 12 is amplified and transmitted to the positioning block 5 through the lever effect, and the positioning block 5 transmits the amplified force to the piezoelectric energy harvesting unit 3.

[0051] Mass block 2, cantilever beam 1 and piezoelectric energy harvesting unit 3 form a vibration system. Under external vibration excitation, mass block 2 drives cantilever beam 1 to vibrate. The horizontal and vertical vibrations are converted into horizontal forces through the L-shaped structure. The force is amplified by lever principle and transmitted to piezoelectric energy harvesting unit 3. Finally, electrical energy is extracted through wires.

[0052] The bidirectional vibration piezoelectric energy harvesting device provided in this invention, through the geometric configuration and dynamic response characteristics of the cantilever beam 1, synchronously couples the vertical and horizontal vibration energy generated by the mass block 2 into the horizontal input of the piezoelectric energy harvesting unit 3, achieving integrated collection of multi-directional vibration energy. Utilizing the lever amplification effect, it significantly improves environmental adaptability and energy conversion efficiency, overcoming the technical bottlenecks of traditional devices' sensitivity to vibration direction and low energy utilization. This bidirectional vibration piezoelectric energy harvesting device can be widely applied in complex transportation infrastructure scenarios such as railway bridges, tunnels, and subways, achieving free deployment and stable operation. By efficiently collecting multi-directional environmental vibration energy and converting it into electrical energy, this device can provide a continuous and reliable energy supply for IoT terminal devices such as structural health monitoring systems and ecological environment monitoring networks, demonstrating significant technical practicality and application prospects.

[0053] Furthermore, in related technologies, vibration energy harvesting devices employ a thin plate-like partition vertically placed between two piezoelectric energy harvesting units. A mass block is fixed to the top of the partition plate, and the vibration force is amplified and transmitted to the piezoelectric energy harvesting units through a resonant amplification mechanism between the mass block, the partition plate, and the force amplification frame. Compared with this prior art vibration energy harvesting device, the embodiment of this invention uses a rigid cantilever beam. Compared to a flexible beam composed of a thin plate-like partition plate, the deformation amplitude is smaller, reducing energy loss and enabling a greater degree of force transmission to the piezoelectric energy harvesting units, significantly improving force transfer efficiency. The force transmission in the embodiment of this invention mainly relies on a lever structure, amplifying and transmitting force through the lever effect without relying on large-amplitude deformation, providing a reliable force transmission path for the rigid beam. At the same time, the L-shaped rigid cantilever beam 1 used in the embodiment of this invention can effectively resist tensile and compressive stresses, avoiding the problem of fracture or damage caused by frequent bending of flexible beams, and extending service life.

[0054] It should be noted that the bidirectional vibration piezoelectric energy harvesting device in this embodiment of the invention adopts a modular design, consisting of multiple independent piezoelectric energy harvesting modules arranged in parallel, and finally encapsulated within a box-type outer frame 7. For example... Figure 8 As shown, the outer box frame 7 has a hollow cuboid structure, and the fixed frame is fixed to the inner wall of the outer box frame 7. This modular integrated design achieves the scalability of the overall power of the device through parallel expansion, enabling the system to adapt to energy harvesting needs of different scales.

[0055] Figure 4 This is a schematic diagram of the structure of a piezoelectric energy harvesting unit according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the force amplification frame according to an embodiment of the present invention. (See attached diagram.) Figure 4 and Figure 5 In some embodiments, the piezoelectric energy harvesting unit 3 may include: a force amplification frame 32 and a piezoelectric stack 311 assembly 31; the force amplification frame 32 includes: a first force-bearing beam 321, a second force-bearing beam 322 and two connecting beams 323; the first force-bearing beam 321, the second force-bearing beam 322 and the two connecting beams 323 are connected to each other to form a frame structure; the first force-bearing beam 321 and the second force-bearing beam 322 are arranged opposite to each other; the first force-bearing beam 321 is fixedly connected to the longitudinal beam 12 through a positioning block 5; the second force-bearing beam 322 is connected to the fixed frame through a positioning block 5; the piezoelectric stack 311 assembly 31 is installed in the force amplification frame 32, and both ends of the piezoelectric stack 311 assembly 31 are respectively connected to the two connecting beams 323.

[0056] The first force-bearing beam 321 and the second force-bearing beam 322 can each be designed as an arched structure, with the arched surface protruding from the side away from the piezoelectric stack 311 assembly 31, and the angle between the arch apex and the line connecting the two arch feet is an obtuse angle. Both the first force-bearing beam 321 and the second force-bearing beam 322 are made of rigid materials. The arch apex of the first force-bearing beam 321 and the second force-bearing beam 322 are respectively connected to the longitudinal beam 12 or the fixed frame via positioning blocks 5, and the arch feet of the first force-bearing beam 321 and the second force-bearing beam 322 are respectively connected to the connecting beam 323, forming a complete force transmission path. To ensure that the horizontal force transmitted by the longitudinal beam 12 can be transmitted to the force amplification frame 32 without loss, the positioning block 5 can be set perpendicular to the longitudinal beam 12. The connecting beam 323 is provided with a boss 3231 having a mounting groove 3231a, facilitating the installation and disassembly of the piezoelectric stack 311 assembly 31.

[0057] Mass block 2, cantilever beam 1, force amplification frame 32, and piezoelectric stack 311 assembly 31 form a single-degree-of-freedom vibration system. Under external vibration excitation, mass block 2 drives cantilever beam 1 to generate multi-directional vibration. Its L-shaped structure unifies the horizontal and vertical vibrations into a horizontal force. This force is initially amplified by positioning block 5 through a lever mechanism and then transmitted to force amplification frame 32. Force amplification frame 32 adopts an optimized obtuse-angled arch structure design to amplify the force a second time, ultimately significantly enhancing the tensile and compressive stresses borne by the piezoelectric stack 311 module, thereby greatly improving the electromechanical energy conversion efficiency. This dual amplification mechanism effectively solves the technical problem of low energy conversion efficiency of traditional piezoelectric energy harvesting devices under low-amplitude vibration environments.

[0058] Specifically, see Figure 4 In some embodiments, the piezoelectric stack 311 assembly 31 includes a piezoelectric stack 311 and a fixing block 312. The two ends of the piezoelectric stack 311 are respectively bonded to the fixing block 312 by epoxy resin adhesive layers. The fixing block 312 is placed in the corresponding mounting groove 3231a. The mounting groove 3231a and the mating surface of the fixing block 312 are provided with mounting holes. The fixing block 312 is fixed in the mounting groove 3231a by bolt fastening. This threaded connection method facilitates the installation and maintenance of the piezoelectric stack 311 assembly 31.

[0059] The piezoelectric stack 311 includes a piezoelectric substrate 3111 and a conductive sheet 3112. The piezoelectric substrate 3111 and the conductive sheet 3112 are stacked alternately to form an integral structure. The outermost conductive sheet 3112 is bonded to an insulating ceramic layer with an epoxy resin adhesive layer for insulation encapsulation. The insulating ceramic layer is then bonded to a fixing block 312 with an epoxy resin adhesive layer to form a stable overall structure. The conductive sheet 3112 is a rectangular metal sheet, and each layer of conductive sheet 3112 is connected to an external wire via a contact connection structure. The piezoelectric substrate 3111 is a rectangular piezoelectric ceramic sheet, and each layer of piezoelectric substrate 3111 is connected to the wire in parallel. The thickness of the piezoelectric substrate 3111 is less than 3 mm, and the number of piezoelectric ceramic sheets is not less than 15.

[0060] Figure 6 This is a schematic diagram of a right-angled J-shaped frame according to an embodiment of the present invention. (See attached diagram.) Figure 2 and Figure 6 In some embodiments, the fixed frame includes two right-angled J-shaped frames 41; each right-angled J-shaped frame 41 includes a short plate 412, a long plate 411, and a base plate; the short plate 412, the long plate 411, and the base plate are connected to each other to form a U-shaped structure with an open end, and the short plate 412 and the long plate 411 are arranged opposite to each other; the two right-angled J-shaped frames 41 are symmetrically arranged and the outer surfaces of the two short plates 412 are fitted together and fastened together by bolts or other means through mounting holes pre-set on the short plates 412 to form an integral rigid structure. The area enclosed by the right-angled J-shaped frames 41 is an accommodating space 4a for installing the piezoelectric energy harvesting unit 3.

[0061] Figure 7 This is a schematic diagram of the structure of a hinge member according to an embodiment of the present invention. (See attached diagram.) Figure 2 and Figure 7 In some embodiments, the bidirectional vibratory piezoelectric energy harvesting device further includes: a hinge 6; the free end of the longitudinal beam 12 is hinged to the short plate 412 via the hinge 6; the hinge 6 includes: a first hinge plate 61, a second hinge plate 62, and a rotating shaft 63; the first hinge plate 61 and the second hinge plate 62 are respectively sleeved on the rotating shaft 63, and both the first hinge plate 61 and the second hinge plate 62 can rotate toward the piezoelectric energy harvesting unit 3; the rotating shaft 63 is installed on the top of the two short plates 412, and its axis extends along the thickness direction of the right-angled J-shaped frame 41; the first hinge plate 61 is inserted between the outer sides of the two short plates 412 and is fixed on the two short plates 412, and the second hinge plate 62 is installed on the side of the longitudinal beam 12; the second force-bearing beam 322 is connected to the long plate 411 via a positioning block 5. Both the short plate 412 and the long plate 411 have pre-drilled mounting holes, which can be used to connect with other components by bolts or other fastening methods.

[0062] The assembly process of the bidirectional vibration piezoelectric energy harvesting device is as follows:

[0063] 1) In step S101, the free end of the crossbeam 11 of the cantilever beam 1 is provided with a mounting hole, and the mass block 2 is fixed in the mounting hole by bolts, adhesive or welding.

[0064] 2) Place the two right-angled J-shaped frames 41 symmetrically, with the outer surfaces of the two short plates 412 touching, and fasten them with bolts to connect the two right-angled J-shaped frames 41 into a whole. Fit the first hinge and the second hinge onto the rotating shaft 63, which is positioned along the width of the right-angled J-shaped frame 41 at the top of the two short plates 412. The first hinge 61 and the second hinge 62 can rotate toward the accommodating space 4a. Insert the first hinge 61 between the outer surfaces of the two short plates 412, and fix the first hinge plate 61 to the two short plates 412 with bolts. The second hinge is fixed to the free end of the longitudinal beam 12 with bolts.

[0065] 3) Stack and align the piezoelectric stack 311, insulating ceramic sheet, and fixing block 312 sequentially, apply epoxy resin adhesive to the contact points to fix them together, and then place the fixing block 312 in the mounting groove 3231a. The mounting groove 3231a has pre-set mounting holes, and the fixing block 312 is fastened in the mounting groove 3231a with bolts. After the piezoelectric energy harvesting unit 3 is assembled, it is placed in the accommodating space 4a, with one piezoelectric energy harvesting unit 3 in each accommodating space 4a. Then, the second force bearing beam 322 of the force amplification frame 32 is fixed to the inner side wall of the long plate 411 with bolts, and the first force bearing beam 321 is fixed to the longitudinal beam 12 with the positioning block 5, thus assembling the piezoelectric energy harvesting module.

[0066] 4) Arrange multiple independent piezoelectric energy harvesting modules side by side and encapsulate them in a box-type outer frame 7. The box-type outer frame 7 has a hollow cuboid structure. Fix the long plate 411 of the right-angled J-shaped frame 41 to the inner side wall of the box-type outer frame 7 with bolts to complete the overall assembly.

[0067] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, elements, and circuits are not described in detail.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bidirectional vibratory piezoelectric energy harvesting device, characterized in that, The system includes a piezoelectric energy harvesting module, which comprises: a cantilever beam, a mass block, a piezoelectric energy harvesting unit, a fixed frame, and a positioning block. The cantilever beam has an L-shaped structure, and the mass block is fixed to the free end of the crossbeam of the cantilever beam. The mass block is used to transfer the environmental vibration energy to the cantilever beam. The cantilever beam is a rigid body. The fixed frame has an open end, and the free end of the longitudinal beam of the cantilever beam extends into the fixed frame from the open end; the longitudinal beam divides the interior of the fixed frame into two identical accommodating spaces, and each accommodating space is equipped with one of the piezoelectric energy harvesting units. The free end of the longitudinal beam is hinged to the fixed frame, and each piezoelectric energy harvesting unit is fixedly connected to the longitudinal beam through a positioning block. The longitudinal beam forms a lever structure with the hinge point as the fulcrum and the positioning block. The longitudinal beam amplifies and transmits the vibration force transmitted by the mass block to the positioning block through the lever effect. The positioning block transmits the amplified force to the piezoelectric energy harvesting unit, so that the piezoelectric energy harvesting unit vibrates with the cantilever beam. The piezoelectric energy harvesting unit converts environmental vibration energy into electrical energy through the piezoelectric effect, and the piezoelectric energy harvesting unit transmits the electrical energy through a wire. The piezoelectric energy harvesting unit includes: a piezoelectric stack assembly and a force amplification frame; The force amplification frame includes: a first force-bearing beam, a second force-bearing beam, and two connecting beams; the first force-bearing beam, the second force-bearing beam, and the two connecting beams are connected to each other to form a frame structure; the first force-bearing beam and the second force-bearing beam are arranged opposite to each other; the first force-bearing beam is fixedly connected to the longitudinal beam through a positioning block; the second force-bearing beam is connected to the fixed frame through a positioning block. The piezoelectric stack assembly is installed inside the force amplification frame, and both ends of the piezoelectric stack assembly are connected to two connecting beams respectively; The first load-bearing beam and the second load-bearing beam are respectively arched structures. The arch tops of the first load-bearing beam and the second load-bearing beam are respectively connected to the positioning block, and the arch feet of the first load-bearing beam and the second load-bearing beam are respectively connected to the connecting beam. The connecting beam has a boss on one side within the force amplification frame, and the surface of the boss has a mounting groove; the two ends of the piezoelectric stack assembly are respectively placed in the two mounting grooves.

2. The bidirectional vibratory piezoelectric energy harvesting device according to claim 1, characterized in that, The piezoelectric stack assembly includes: a piezoelectric stack and a fixing block; The piezoelectric stack includes a piezoelectric substrate and a conductive sheet; the piezoelectric substrate and the conductive sheet are stacked alternately to form an integral structure; both ends of the piezoelectric stack are connected to a fixing block through an adhesive layer, and the fixing block is placed in the corresponding mounting groove.

3. The bidirectional vibration piezoelectric energy harvesting device according to claim 2, characterized in that, The piezoelectric stack assembly further includes: an insulating layer; The insulating layer is disposed between the piezoelectric stack and the fixing block; the insulating layer is connected to the piezoelectric stack and the fixing block respectively through an adhesive layer.

4. The bidirectional vibratory piezoelectric energy harvesting device according to claim 1, characterized in that, The fixed frame includes: two right-angled J-shaped frames; each right-angled J-shaped frame includes: a short plate, a long plate, and a bottom plate; the short plate, long plate, and bottom plate are connected to each other to form a J-shaped structure with an open end, and the short plate and long plate are arranged opposite to each other; the two right-angled J-shaped frames are symmetrically arranged and the outer surfaces of the short plates of the two right-angled J-shaped frames are fitted together; the longitudinal beam is hinged to the short plate.

5. The bidirectional vibration piezoelectric energy harvesting device according to claim 4, characterized in that, Also includes: Hinged joints; The hinge includes: a first hinge plate, a second hinge plate, and a pivot. The first hinge plate and the second hinge plate are respectively sleeved on the rotating shaft; the rotating shaft is set on the top of the two short plates, the first hinge plate is inserted between the outer sides of the two short plates and the first hinge plate is fixed on the two short plates, and the second hinge plate is installed on the side of the longitudinal beam; the second load-bearing beam is connected to the long plate through a positioning block.

6. The bidirectional vibratory piezoelectric energy harvesting device according to claim 2, characterized in that, The thickness of the piezoelectric substrate is less than 3 mm, and the number of piezoelectric substrates is not less than 15.

Images