Bridge expansion joint-oriented vibration power generation device and method

Abstract

The application provides a vibration power generation device and method for bridge expansion joints, and belongs to the technical field of bridge engineering structure energy recovery and micro new energy power generation. The device comprises two force transmission top plates, a plurality of piezoelectric sheets are installed on the force transmission top plates, a rhombic force transmission structure and a plurality of piezoelectric power generation units are installed between the two force transmission top plates, the piezoelectric power generation unit comprises a reset spring assembly and a stacked piezoelectric power generation device, the transmission rack of the rhombic force transmission structure is engaged with a gear transmission displacement amplification mechanism, and the gear transmission displacement amplification mechanism is connected with an electromagnetic power generation unit. The application realizes low-loss transmission and efficient amplification of displacement, fully plays the performance of the composite power generation unit, and guarantees the structural compatibility with the existing expansion joints, without changing the original stress characteristics and the core displacement compensation function.

Description

Technical Field

[0001] This invention belongs to the field of energy recovery and micro-new energy power generation technology in bridge engineering structures, specifically relating to a vibration power generation device and method for bridge expansion joints. Background Technology

[0002] With the development of intelligent operation and maintenance technology for bridge engineering, bridge health monitoring systems have widely deployed low-power sensor terminals, wireless transmission modules, and other equipment. A continuous and stable power supply for these devices is a core prerequisite for the normal operation of the system. Existing bridge monitoring equipment mostly uses municipal power grids or chemical batteries for power: municipal power requires the installation of power lines, resulting in high construction and wiring costs, and coverage is difficult for bridges in remote areas; chemical batteries have a limited lifespan, requiring regular manual replacement, leading to high operation and maintenance costs, and discarded batteries pose an environmental pollution risk, making it difficult to meet the long-term low-maintenance, unmanned operation and maintenance needs of bridges. Therefore, collecting the mechanical energy generated during bridge service and converting it into electrical energy to achieve energy self-sufficiency for monitoring equipment has become an important research direction in this field.

[0003] In the field of mechanical energy generation and micro-energy harvesting technology, piezoelectric power generation and electromagnetic power generation are two widely researched and applied technologies. Piezoelectric power generation is based on the positive piezoelectric effect of piezoelectric materials. When a piezoelectric medium deforms under external mechanical force, its interior becomes polarized, and the corresponding surfaces generate equal amounts of opposite charges, directly converting mechanical energy into electrical energy. The core technical characteristics of this technology are compact structure, fast response speed, no electromagnetic interference, easy miniaturization and modular integration, and suitability for low-frequency micro-amplitude vibration / displacement scenarios. Currently, piezoelectric power generation technology has been applied in energy recovery scenarios such as road vehicle vibration, rail transit wheel-rail vibration, and building structure vibration. For different stress conditions, the industry has developed adaptable piezoelectric structures. Among them, stacked piezoelectric power generation structures can withstand large vertical loads, have high energy density, and are suitable for low-frequency high-pressure conditions; piezoelectric cantilever beam structures can amplify micro-deformation and have high response sensitivity to small displacements and vibrations, and can be used for broadband micro-vibration energy harvesting. However, the single piezoelectric power generation scheme has inherent limitations: its energy conversion efficiency is highly dependent on the deformation range of the piezoelectric material, it has poor adaptability to large reciprocating displacement, and over-range displacement is prone to fatigue damage to the piezoelectric material, and the output power is limited under low-frequency quasi-static displacement.

[0004] Electromagnetic power generation is based on Faraday's law of electromagnetic induction, which states that when a closed conductor moves in a magnetic field, cutting magnetic field lines, an induced electromotive force is generated in the circuit, converting mechanical energy into electrical energy. The core technical features of this technology are stable output power, adaptability to low-to-medium frequency reciprocating linear displacement, and long service life. Currently, electromagnetic power generation technology has been applied in research and engineering pilot projects in scenarios such as ocean wave energy recovery and reciprocating energy harvesting in rail transit. To improve power generation efficiency under small displacements, the industry often uses transmission mechanisms to convert linear reciprocating motion into rotational motion, increasing the speed at which the conductor cuts magnetic field lines, lowering the power generation start-up threshold, and improving energy conversion efficiency. However, a single electromagnetic power generation scheme has inherent limitations: its response sensitivity to micro-displacements is insufficient, and there is a start-up displacement threshold, making it difficult to achieve effective power generation under the daily temperature-induced micro-displacements of bridge expansion joints; conventional displacement amplification mechanisms occupy a large space and have high transmission losses, making them unsuitable for the narrow installation space of bridge expansion joints.

[0005] Bridge expansion joints are essential core components of bridge structures, used to compensate for axial expansion and contraction displacements caused by factors such as temperature changes, vehicle loads, concrete creep and shrinkage, and foundation settlement, ensuring ride comfort and structural safety. During bridge service, vehicle impacts and temperature variations cause continuous reciprocating displacement of the expansion joints. The mechanical energy generated in this process is currently mostly dissipated through structural damping and friction, without effective recovery and utilization, resulting in a waste of renewable energy.

[0006] Current research on energy recovery in bridge structures mainly focuses on energy harvesting from the vibration of the main bridge beam and the vibration of vehicles on the bridge deck. There are relatively few technologies related to energy recovery from the displacement of bridge expansion joints, and existing solutions suffer from the following key shortcomings: First, most adopt a single piezoelectric or electromagnetic power generation mode, which is difficult to simultaneously adapt to the full range of operating conditions, including the small-amplitude temperature-induced displacement of expansion joints and the large displacement caused by vehicle impacts. This results in a narrow energy harvesting bandwidth and poor adaptability to operating conditions. Second, there is a lack of efficient transmission and displacement amplification mechanisms suitable for the confined installation space of expansion joints. Displacement transmission losses are high, the amplification ratio is insufficient, and it is difficult to fully utilize the performance of the power generation unit. Third, the structural compatibility between the device and the bridge expansion joint is insufficient, which can easily affect the original displacement compensation function of the expansion joint or impose additional loads on the main bridge structure, making it difficult to adapt to the complex outdoor service environment of bridges. Fourth, existing solutions often fail to consider the energy supply requirements for bridge health monitoring, and the engineering application scenarios for energy recovery are unclear.

[0007] Existing bridge expansion joints are essential core components for compensating for the expansion and contraction displacement of bridge beams. During service, the mechanical energy of reciprocating displacement caused by temperature changes and vehicle loads is largely dissipated and wasted through structural damping. Existing bridge health monitoring equipment mostly relies on municipal power grids or chemical batteries for power supply, resulting in high costs, limited coverage, and difficult operation and maintenance. Research on energy recovery for bridge structures has largely focused on the vibration of main beams and bridge decks, with very few mature solutions for energy recovery from expansion joint displacement, and most of them employ a single piezoelectric or single electromagnetic power generation mode. Furthermore, existing technologies have the following technical defects: First, the power supply schemes of existing monitoring equipment cannot meet the on-site self-powering requirements of long-term low-maintenance and unmanned operation and maintenance of bridges; second, existing single-power generation mode expansion joint energy recovery schemes, due to their inherent limitations, cannot simultaneously adapt to the full range of operating conditions, including the small-amplitude temperature-induced displacement of expansion joints and the large-amplitude displacement caused by vehicle impacts, resulting in low energy recovery efficiency and poor adaptability to operating conditions; third, existing solutions lack efficient transmission and displacement amplification mechanisms adapted to the confined installation space of expansion joints, resulting in high displacement transmission losses and insufficient compatibility with the expansion joint structure, posing a risk to its core displacement compensation function and insufficient engineering practicality. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned technical problems and provide a vibration power generation device and method for bridge expansion joints.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A vibration power generation device for bridge expansion joints includes: two force transmission top plates, on which multiple piezoelectric plates are mounted; a rhomboid force transmission structure and multiple piezoelectric power generation units are installed between the two force transmission top plates; each piezoelectric power generation unit includes a return spring assembly and a stacked piezoelectric power generation device; the transmission rack of the rhomboid force transmission structure meshes with a gear transmission displacement amplification mechanism; and the gear transmission displacement amplification mechanism is connected to an electromagnetic power generation unit.

[0011] Furthermore, the rhomboid force transmission structure includes a base, and two linkage mechanisms are hinged between the two bases. The two linkage mechanisms are symmetrically arranged, and each linkage mechanism includes a connecting rod hinged through a rotating shaft. The two rotating shafts are respectively hinged to a transmission rack and a rack fixing member, and the rack is slidably mounted on the rack fixing member.

[0012] Furthermore, the gear transmission displacement amplification mechanism includes a primary input gear, which meshes with the rack and the multi-stage speed-increasing gear set respectively. The final gear of the multi-stage speed-increasing gear set is mounted on the output transmission shaft. There are transmission gears at the upper and lower ends of the output transmission shaft respectively. The transmission gears mesh with transmission gears, and the transmission gears are mounted on the input shaft of the electromagnetic power generation unit.

[0013] Furthermore, the piezoelectric power generation unit also includes linear bearings respectively installed on the two force transmission top plates, the linear bearings being connected to the return spring assembly, and a stacked piezoelectric power generation device being installed between the two return spring assemblies.

[0014] Furthermore, the stacked piezoelectric power generation device includes two cover plates, with multiple supports and multiple stacked piezoelectric blocks disposed between the two cover plates, and a force steering block installed between every two stacked piezoelectric blocks, the force steering block being connected to the support.

[0015] Furthermore, the support has two inclined planes, the angle between the inclined planes and the horizontal plane being 10°-20°.

[0016] Furthermore, the angle formed between the inclined plane and the horizontal plane of the inclined plane structure is 15°.

[0017] Furthermore, the electromagnetic power generation unit includes an input shaft, on which a one-way ratchet is mounted. The one-way ratchet is connected to a magnet rotor, which is rotatably mounted on a magnet rotor mounting bracket. A coil stator is mounted below the magnet rotor and on a coil stator mounting bracket. The magnet rotor and the coil stator are coaxially mounted and have a gap between them.

[0018] The present invention may also include:

[0019] A vibration-based power generation method for bridge expansion joints, utilizing the aforementioned device, includes the following steps:

[0020] The device is embedded in the displacement working area between the left and right beams of the bridge expansion joint. When a slight displacement occurs, the piezoelectric sheet on the top plate bends and deforms, generating piezoelectric energy. At the same time, the displacement compresses the return spring assembly, which transmits the force to the stacked piezoelectric power generation device, which generates piezoelectric energy again after being compressed.

[0021] When encountering a large displacement, the diamond-shaped force transmission structure extends and pushes the transmission rack, which amplifies the speed through a multi-stage speed-increasing gear set and drives the electromagnetic power generation unit. The input shaft drives the magnet rotor to rotate at high speed in one direction through a one-way ratchet, and the coil stator cuts the magnetic field lines to generate induced electrical energy.

[0022] The electrical energy output from the two power generation paths mentioned above is rectified and stabilized before being combined to provide a self-powered power source for the bridge health monitoring equipment.

[0023] The beneficial effects of this invention are as follows:

[0024] This invention directly uses the reciprocating displacement that inevitably occurs during the service of expansion joints as an energy source, completing the conversion of mechanical energy into electrical energy on-site. It eliminates the need for external municipal power grid wiring and periodic replacement of chemical batteries, thus realizing the resource utilization of waste displacement energy and fundamentally solving the problem of stable on-site self-powering for monitoring equipment. This significantly reduces the construction and operation and maintenance costs throughout the system's life cycle and avoids the environmental pollution risks of waste batteries.

[0025] This invention adopts a piezoelectric-electromagnetic coupling composite power generation architecture. The electromagnetic power generation unit adapts to the large reciprocating displacement caused by vehicle passage, while the piezoelectric sheet adapts to the small temperature-induced displacement during daily use. The two power generation modes complement each other, which not only solves the problems of insufficient response to small displacement and high start-up threshold of single electromagnetic power generation, but also avoids the shortcomings of poor adaptability to large displacement and easy fatigue damage of single piezoelectric power generation. It realizes energy recovery of expansion joints under all working conditions and in a wide frequency band, greatly improves the overall energy conversion efficiency, and ensures stable power output at all times.

[0026] This invention presents a composite transmission scheme that combines a rhombic force transmission structure with a gear-driven displacement amplification mechanism for expansion joint installation space. The device can be directly installed in the existing displacement area of ​​the expansion joint without requiring large-scale modifications to the main bridge structure or the core structure of the expansion joint. The rhombic force transmission structure can transmit horizontal displacement and vertical load with low loss within a limited space, while the gear transmission mechanism can efficiently convert small linear displacements into high-speed rotational motion. This achieves both low-loss transmission and efficient amplification of displacement, fully utilizing the performance of the composite power generation unit, while ensuring structural compatibility with existing expansion joints, without altering their original stress characteristics and core displacement compensation function, and without imposing additional loads on the main bridge structure. It is suitable for installation on newly built bridges and renovation of existing bridges, has strong adaptability to complex outdoor service environments, and possesses extremely high engineering practicality and scalability. Attached Figure Description

[0027] Appendix Figure 1 This is a schematic diagram of the structure of the present invention;

[0028] Appendix Figure 2 This is a schematic diagram of the structure of the piezoelectric power generation unit of the present invention;

[0029] Appendix Figure 3 This is a schematic diagram of the rhomboid force transmission structure and gear transmission displacement amplification mechanism of the present invention;

[0030] Appendix Figure 4 This is an exploded view of the electromagnetic power generation unit of the present invention;

[0031] Appendix Figure 5 This is an exploded view of the piezoelectric power generation unit of the present invention;

[0032] Appendix Figure 6 This is a schematic diagram of the rhomboid force transmission structure of the present invention.

[0033] In the attached diagram: 1. Piezoelectric element; 2. Reset spring assembly; 3. Stacked piezoelectric generator; 3-1. Cover plate; 3-2. Bracket; 3-3. Force steering block; 3-4. Stacked piezoelectric block; 4. Rhomboid force transmission structure; 4-1. Base; 4-2. Rack; 4-3. Rack fixing component; 4-4. Connecting rod; 5. Gear transmission displacement amplification mechanism; 5-1. First-stage input gear; 5-2. Last-stage gear; 5-3. Transmission gear one; 5-4. Transmission gear two; 5-5. Output transmission shaft; 6. Force transmission top plate; 7. Electromagnetic generator unit; 7-1. One-way ratchet; 7-2. Magnet rotor; 7-3. Input shaft; 7-4. Magnet rotor fixing frame; 7-5. Coil stator; 7-6. Coil stator fixing frame; 8. Linear bearing. Detailed Implementation

[0034] The present invention will now be further described with reference to the accompanying drawings.

[0035] A vibration power generation device for bridge expansion joints, as shown in the attached figure. Figure 1 As shown, it includes: two force transmission top plates 6, on which multiple piezoelectric plates 1 are installed; a rhomboid force transmission structure 4 and multiple piezoelectric power generation units are installed between the two force transmission top plates; each piezoelectric power generation unit includes a reset spring assembly 2 and a stacked piezoelectric power generation device 3; the transmission rack 4-2 of the rhomboid force transmission structure 4 meshes with a gear transmission displacement amplification mechanism 5; and the gear transmission displacement amplification mechanism 5 is connected to an electromagnetic power generation unit 7.

[0036] As attached Figure 2 As shown, the piezoelectric power generation unit also includes linear bearings 8 respectively installed on the two force transmission top plates. The linear bearings 8 are connected to the return spring assembly 2, and a stacked piezoelectric power generation device 3 is installed between the two return spring assemblies 2.

[0037] As attached Figure 5 As shown, the stacked piezoelectric power generation device 3 includes two cover plates 3-1, with multiple supports 3-2 and multiple stacked piezoelectric blocks 3-4 arranged between the two cover plates. A force steering block 3-3 is installed between every two stacked piezoelectric blocks 3-4, and the force steering block 3-3 is connected to the support 3-2.

[0038] The bracket 3-2 has two inclined plane structures, with an angle of 10°-20° between the inclined plane and the horizontal plane, preferably 15°. The inclined plane is used to make contact with the force steering block, converting the pressure F input in the vertical direction into a component force along the inclined plane direction, thereby pushing the force steering block to move horizontally.

[0039] Force and transmission relationship: The upper end of the bracket is in contact with or fixed to the cover plate, bearing the vertical pressure F transmitted from the cover plate. The inclined surface of the bracket abuts against the force-directing block. After the pressure F is decomposed by the inclined surface, a normal component perpendicular to the inclined surface is generated. This component force pushes the force-directing block to laterally compress the stacked piezoelectric blocks. By setting the angle of the inclined surface of the bracket, the force can be amplified. The bracket is installed between the cover plate and the force-directing block, and its bottom or side is provided with a limiting structure (such as a guide groove or positioning boss) to ensure that the bracket maintains stable inclined surface contact during the force process and avoids lateral slippage. The force-directing block is located on the inclined side of the bracket, and the stacked piezoelectric blocks are placed on the other side of the force-directing block. When the bracket is compressed, the force-directing block moves horizontally to compress the stacked piezoelectric blocks, realizing piezoelectric power generation.

[0040] The bracket is made of high-strength metal materials (such as stainless steel or alloy steel), and its inclined surface is precision machined to ensure a good fit with the force steering block, reducing stress concentration and energy loss.

[0041] As attached Figure 3 As shown, the gear transmission displacement amplification mechanism 5 includes a first-stage input gear 5-1, which meshes with the rack 4-2 and the multi-stage speed-increasing gear set. The last-stage gear 5-2 of the multi-stage speed-increasing gear set is mounted on the output transmission shaft 5-5. The upper and lower ends of the output transmission shaft 5-5 are respectively equipped with a first transmission gear 5-3, which meshes with a second transmission gear 5-4. The second transmission gear 5-4 is mounted on the input shaft 7-3 of the electromagnetic power generation unit 7.

[0042] As attached Figure 4 As shown, the electromagnetic power generation unit 7 includes an input shaft 7-3, on which a one-way ratchet 7-1 is mounted. The one-way ratchet 7-1 is connected to a magnet rotor 7-2. The magnet rotor 7-2 is rotatably mounted on a magnet rotor mounting bracket 7-4. A coil stator 7-5 is mounted below the magnet rotor 7-2. The coil stator 7-5 is mounted on a coil stator mounting bracket 7-6. The magnet rotor 7-2 and the coil stator 7-5 are coaxially mounted and have a gap between them.

[0043] As attached Figure 6 As shown, the rhomboid force transmission structure 4 includes a base 4-1, and two linkage mechanisms are hinged between the two bases 4-1. The two linkage mechanisms are symmetrically arranged. Each linkage mechanism includes a connecting rod 4-4 hinged through a rotating shaft. The two rotating shafts are respectively hinged to a transmission rack 4-2 and a rack fixing member 4-3. The rack 4-2 is slidably mounted on the rack fixing member 4-3.

[0044] Working principle:

[0045] The device is embedded in the displacement working area between the left beam and the right beam of the bridge expansion joint. When a slight displacement occurs, the piezoelectric sheet 1 on the top plate 6 bends and deforms, generating piezoelectric energy. At the same time, the displacement causes the reset spring assembly 2 to be compressed, which transmits the force to the stacked piezoelectric generator 3, and generates piezoelectric energy again after being compressed.

[0046] When encountering a large displacement, the diamond-shaped force transmission structure 4 extends and pushes the transmission rack, which amplifies the speed through a multi-stage speed-increasing gear set and drives the electromagnetic power generation unit 7. The input shaft 7-3 drives the magnet rotor 7-2 to rotate at high speed in one direction through the one-way ratchet 7-1, and the coil stator 7-5 cuts the magnetic field lines to generate induced electrical energy.

[0047] The electrical energy output from the two power generation paths mentioned above is rectified and stabilized before being combined to provide a self-powered power source for the bridge health monitoring equipment.

[0048] This invention relates to a vibration power generation device for bridge expansion joints, which is integrally embedded within the displacement working area between the left and right beams of the bridge expansion joint. When the bridge undergoes horizontal reciprocating displacement due to temperature changes or vehicle traffic, the displacement is transmitted to the device through a force transmission top plate. The device automatically selects two coordinated power generation paths based on the displacement amplitude:

[0049] Piezoelectric power generation path under micro-displacement: When the expansion joint produces a daily temperature-induced micro-displacement (e.g., a slow displacement within a few millimeters), the force-transmitting top plate displacement forces the piezoelectric sheet (1) to bend and deform. The piezoelectric sheet on its surface generates charge due to the positive piezoelectric effect, realizing the first stage of piezoelectric power generation. At the same time, the displacement continues to be transmitted to the reset spring assembly below it through the rhomboid force transmission structure. After being compressed, the reset spring assembly transmits the force to the stacked piezoelectric power generation device. The stacked piezoelectric blocks are compressed, generating the second stage of piezoelectric power generation. The reset spring assembly provides preload and return force during the displacement return stroke to ensure continuous operation of the device.

[0050] Electromagnetic power generation path under large displacement: When the expansion joint experiences significant reciprocating displacement due to vehicle traffic, the force transmission top plate pushes the piezoelectric plate and the rhomboid force transmission structure. The rhomboid force transmission structure consists of four sets of equal-length connecting rods hinged together to form a closed-loop rhombus, with its left lateral hinge point rigidly connected to the transmission rack. The rhomboid structure expands and contracts with the displacement of the expansion joint, converting the horizontal displacement into the linear reciprocating motion of the transmission rack. The tooth surface of the transmission rack meshes with the first-stage input gear of the gear transmission displacement amplification mechanism, converting linear motion into rotational motion; the first-stage input gear meshes in series with a multi-stage speed-increasing gear set, achieving progressive amplification of rotational speed. The final-stage gear is coaxially fixed with the output transmission shaft, which transmits the high-speed rotational motion to the electromagnetic power generation unit.

[0051] The output drive shaft of the gear-driven displacement amplification mechanism is coaxially fixed to the inner ring of a one-way ratchet via a flat key or spline. The outer ring of the one-way ratchet is rigidly connected to the rotor support of the magnet rotor. The one-way ratchet ensures that the magnet rotor always rotates in one direction, avoiding alternating forward and reverse rotation caused by the reciprocating motion of the expansion joint. The magnet rotor consists of a rotor support and permanent magnets evenly embedded along its circumference, rotatably supported on a fixed frame via bearings. The coil stator is fixed to the fixed frame, coaxially fitted with the magnet rotor, and maintains a uniform air gap. When the magnet rotor rotates at high speed in one direction, the coil stator cuts the rotating magnetic field, generating an alternating induced electromotive force according to Faraday's law of electromagnetic induction.

[0052] The electrical energy generated by piezoelectric elements and stacked piezoelectric generators, as well as the electrical energy generated by the electromagnetic generator unit, is processed by rectification, filtering, and voltage regulation circuits before being combined and output as a stable DC power supply to power the low-power sensors, wireless transmission modules, and other equipment in the bridge health monitoring system. The two power generation paths work complementaryly under both small and large displacements, and can also generate power collaboratively under medium displacements, achieving efficient recovery and conversion of mechanical energy into electrical energy across all operating conditions and a wide frequency band for the expansion joints, thus enabling on-site self-powering of the bridge health monitoring equipment.

[0053] 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 present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vibration power generation device for bridge expansion joints, characterized in that, include: Two force transmission top plates (6) are provided, on which multiple piezoelectric plates (1) are installed. A rhomboid force transmission structure (4) and multiple piezoelectric power generation units are installed between the two force transmission top plates. The piezoelectric power generation unit includes a reset spring assembly (2) and a stacked piezoelectric power generation device (3). The transmission rack (4-2) of the rhomboid force transmission structure (4) meshes with a gear transmission displacement amplification mechanism (5). The gear transmission displacement amplification mechanism (5) is connected to an electromagnetic power generation unit (7).

2. The vibration power generation device for bridge expansion joints according to claim 1, characterized in that, The rhomboid force transmission structure (4) includes a base (4-1), and two linkage mechanisms are hinged between the two bases (4-1). The two linkage mechanisms are symmetrically arranged. The linkage mechanism includes a connecting rod (4-4) hinged through a rotating shaft. The two rotating shafts are respectively hinged to a transmission rack (4-2) and a rack fixing member (4-3). The rack (4-2) is slidably mounted on the rack fixing member (4-3).

3. The vibration power generation device for bridge expansion joints according to claim 1, characterized in that, The gear transmission displacement amplification mechanism (5) includes a first-stage input gear (5-1), which meshes with the rack (4-2) and the multi-stage speed-increasing gear set respectively. The last-stage gear (5-2) of the multi-stage speed-increasing gear set is mounted on the output transmission shaft (5-5). The upper and lower ends of the output transmission shaft (5-5) are respectively equipped with a first transmission gear (5-3). The first transmission gear (5-3) meshes with a second transmission gear (5-4). The second transmission gear (5-4) is mounted on the input shaft (7-3) of the electromagnetic power generation unit (7).

4. The vibration power generation device for bridge expansion joints according to claim 1, characterized in that, The piezoelectric power generation unit also includes linear bearings (8) respectively installed on the two force transmission top plates. The linear bearings (8) are connected to the reset spring assembly (2). A stacked piezoelectric power generation device (3) is installed between the two reset spring assemblies (2).

5. The vibration power generation device for bridge expansion joints according to claim 1, characterized in that, The stacked piezoelectric power generation device (3) includes two cover plates (3-1), and multiple supports (3-2) and multiple stacked piezoelectric blocks (3-4) are arranged between the two cover plates. A force steering block (3-3) is installed between every two stacked piezoelectric blocks (3-4), and the force steering block (3-3) is connected to the support (3-2).

6. The vibration power generation device for bridge expansion joints according to claim 5, characterized in that, The bracket (3-2) has two inclined plane structures, and the angle between the inclined plane and the horizontal plane is 10°-20°.

7. The vibration power generation device for bridge expansion joints according to claim 6, characterized in that, The angle between the inclined plane and the horizontal plane of the inclined plane structure is 15°.

8. The vibration power generation device for bridge expansion joints according to claim 1, characterized in that, The electromagnetic power generation unit (7) includes an input shaft (7-3), on which a one-way ratchet (7-1) is mounted. The one-way ratchet (7-1) is connected to a magnet rotor (7-2). The magnet rotor (7-2) is rotatably mounted on a magnet rotor mounting bracket (7-4). A coil stator (7-5) is mounted below the magnet rotor (7-2). The coil stator (7-5) is mounted on a coil stator mounting bracket (7-6). The magnet rotor (7-2) and the coil stator (7-5) are coaxially mounted and have a gap.

9. A vibration-based power generation method for bridge expansion joints, characterized in that, The method, using the apparatus according to any one of claims 1-8, comprises: The device is embedded in the displacement working area between the left beam and the right beam of the bridge expansion joint. When a slight displacement occurs, the piezoelectric sheet (1) on the force transmission top plate (6) will bend and deform, generating piezoelectric energy. At the same time, the displacement will cause the reset spring assembly (2) to be compressed, and the force will be transmitted to the stacked piezoelectric power generation device (3), which will generate piezoelectric energy again after being compressed. When encountering a large displacement, the rhomboid force transmission structure (4) extends and pushes the transmission rack, which drives the electromagnetic power generation unit (7) after the speed is amplified by the multi-stage speed-increasing gear set. The input shaft (7-3) drives the magnet rotor (7-2) to rotate at high speed in one direction through the one-way ratchet (7-1), and the coil stator (7-5) cuts the magnetic field lines to generate induced electric energy. The electrical energy output from the two power generation paths mentioned above is rectified and stabilized before being combined to provide a self-powered power source for the bridge health monitoring equipment.

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