A differential dual-output electromagnetic vibration energy harvesting device

Abstract

The present invention discloses a differential dual-output electromagnetic vibration energy harvesting device, characterized in that the vibration mechanism includes a magnetic conduction framework, a first annular magnet and a second annular magnet, and the induction mechanism includes a first annular induction coil and a second annular induction coil. The magnetic conduction framework is connected to the middle part of the inner side of the outer casing through an elastic connection mechanism. On both sides of the magnetic conduction framework along the axial direction, symmetric depressions are respectively formed to form a first annular installation groove and a second annular installation groove which are separated from each other. The first annular magnet is fixedly sleeved on the inner groove wall of the first annular installation groove, the first annular induction coil is fixedly arranged at one end of the outer casing and extends into the first annular installation groove, the second annular magnet is fixedly sleeved on the inner groove wall of the second annular installation groove, and the second annular induction coil is fixedly arranged at the other end of the outer casing and extends into the second annular installation groove. The advantage is that it can efficiently provide electric energy in the form of differential dual-output.

Description

Technical Field

[0001] The present invention relates to an electromagnetic vibration energy harvesting device, and particularly to a differential dual-output electromagnetic vibration energy harvesting device. Background Art

[0002] Effectively converting the vibration energy widely existing in the environment into electrical energy is one of the most potential and promising technical solutions in the field of self-powered technology. The forms of vibration energy harvesting are divided into piezoelectric, electromagnetic, and electrostatic. Among them, electromagnetic vibration energy harvesting has the advantages of small volume, low cost, large output power, etc., and has received extensive attention in recent years. Its working principle is as follows: environmental vibration drives the spring to cause relative displacement between the magnet and the coil. According to Faraday's law of electromagnetic induction, the magnetic flux through the closed circuit in the magnetic field changes, and an alternating induced electromotive force will be generated in the coil of the circuit.

[0003] A Chinese invention patent with the application number CN202210246852.3 discloses a differential electromagnetic vibration energy harvesting device. The device is provided with an annular chute on the bottom plate, and its inner rolling ball rolls in the annular chute after sensing vibration, driving the bar-shaped limiting groove and the elliptical track to move relative to each other, so that the coil cuts the magnetic induction line to generate electrical energy. This energy harvesting device transmits vibration energy through the multi-directional rolling of the sphere and has the characteristics of differential dual-output; however, there is a large unused space inside this energy harvesting device, resulting in low space utilization rate, and further making the output power density of this energy harvesting device relatively small.

[0004] A Chinese invention patent with the application number CN202311619741.3 discloses an electromagnetic vibration energy collector based on radial magnetization. The device uses a composite magnet, and spring guide sleeves are installed at both the upper and lower ends thereof. The composite magnet reciprocates along the guide rod with the vibration of the object, so that the coil cuts the magnetic induction line to generate electrical energy. This energy harvesting device has a high internal space utilization rate, and at the same time, by shortening the magnetic circuit, the magnetic induction intensity near the coil is increased, greatly increasing the power density of the energy harvesting device. However, the output mode of this energy harvesting device is single output, and this characteristic limits its flexibility and applicability, for example, in the case of rapid energy harvesting or large-capacity energy harvesting. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a differential dual-output electromagnetic vibration energy harvesting device with a simple overall structure and a high energy harvesting power density, which can convert vibration energy into electrical energy output in a differential dual-output form, and the energy harvesting process is relatively fast and flexible.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows: A differential dual-output electromagnetic vibration energy harvesting device, which includes an outer housing, a vibration mechanism, and an induction mechanism. The vibration mechanism includes a magnetic conduction skeleton, a first ring magnet, and a second ring magnet. The induction mechanism includes a first ring induction coil and a second ring induction coil whose ends both extend out of the outer housing. The magnetic conduction skeleton is elastically connected to the middle part of the inner side of the outer housing along the axial direction through an elastic connection mechanism, and symmetrically sunken parts are respectively formed on both sides of the magnetic conduction skeleton along the axial direction to form a mutually separated first ring installation groove and a second ring installation groove. The first ring magnet is fixedly sleeved on the inner groove wall of the first ring installation groove and the magnetization direction is radial. The first ring induction coil is fixedly arranged at one end of the outer housing and non-contactingly extends into the first ring installation groove. The second ring magnet is fixedly sleeved on the inner groove wall of the second ring installation groove and the magnetization direction is radial. The second ring induction coil is fixedly arranged at the other end of the outer housing and non-contactingly extends into the second ring installation groove.

[0007] Compared with the prior art, the advantages of the present invention are that the magnetic conduction skeleton is elastically connected to the middle part of the inner side of the outer housing along the axial direction through an elastic connection mechanism. When vibrating, the magnetic conduction skeleton drives the first ring magnet and the second ring magnet to respectively cut the corresponding first ring induction coil and the second ring induction coil, thereby generating two differential alternating voltages and respectively outputting them from the ends of the first ring induction coil and the second ring induction coil to the outside of the outer housing, completing the energy harvesting process of converting vibration energy into electrical energy. The differential dual-output characteristic of the device has obvious advantages in output power, power supply speed, and power supply efficiency. At the same time, the device has good flexibility and applicability, and can more conveniently meet the requirements when rapid energy harvesting or large-capacity energy harvesting is needed. In addition, the overall device has a simple structure, is compact, and makes full use of the internal space of the device for the design of each structure;

[0008] The magnetization directions of the first ring magnet and the second ring magnet are radial. Compared with axial magnetization, a more uniform magnetic field can be generated, and at the same time, the magnetic path length is shortened, reducing energy loss; through the combination of the magnetic conduction skeleton with magnetism and the first ring magnet and the second ring magnet with radial magnetization, the magnetic circuit structure is closed, reducing magnetic flux leakage and improving the energy harvesting efficiency of the overall device.

[0009] Preferably, the first annular induction coil is fixedly connected to one end of the outer housing through a first coil bracket. The first coil bracket is fixed to one end of the outer housing by the cooperation and locking between a first mounting screw and a first mounting nut. The second annular induction coil is fixedly connected to the other end of the outer housing through a second coil bracket. The second coil bracket is fixed to the other end of the outer housing by the cooperation and locking between a second mounting screw and a second mounting nut. This facilitates the installation of the first annular induction coil and the second annular induction coil, as well as maintenance, replacement, or adjustment after disassembly.

[0010] Preferably, the height of the first annular magnet is less than the height of the inner groove wall of the first annular mounting groove, and the height of the second annular magnet is less than the height of the inner groove wall of the second annular mounting groove. This ensures that the first annular magnet and the second annular magnet do not directly collide with the first coil bracket and the second coil bracket during vibration, which may cause structural changes or damage.

[0011] Preferably, the elastic connection mechanism includes a first flat spring, a second flat spring, and a spring washer. The first flat spring is elastically connected between the outer side of the magnetic conduction skeleton and the inner wall of the outer housing and is perpendicular to the axial direction of the magnetic conduction skeleton when at rest. The second flat spring is elastically connected between the outer side of the magnetic conduction skeleton and the inner wall of the outer housing and is perpendicular to the axial direction of the magnetic conduction skeleton when at rest. The spring washer is fixedly clamped between the outer layer of the first flat spring and the outer layer of the second flat spring. The design of the first flat spring and the second flat spring greatly reduces the internal structural space of the overall device and increases the power density of the overall device. At the same time, both the first flat spring and the second flat spring are perpendicular to the axial direction of the magnetic conduction skeleton. The two parallel flat springs make the vibration of the vibration mechanism more stable, always maintaining axial vibration, preventing the vibration mechanism from tilting and shifting, and avoiding the problem that the vibration mechanism collides with the first annular induction coil and the second annular induction coil with fixed positions during vibration.

[0012] Preferably, the first planar spring includes a first inner ring located on the inner layer, a first outer ring located on the outer layer, and at least three first elastic S-shaped connecting arms that are evenly distributed in the circumferential direction and are elastically connected between the first inner ring and the first outer ring. An installation ring is fixedly arranged at the middle part of the outer side of the magnetic conduction skeleton, and one side of the first inner ring is fixedly connected to the installation ring. The first outer ring is fixedly connected to the inner wall of the housing. The first elastic S-shaped connecting arm includes a first inner connecting section, a first middle connecting section, and a first outer connecting section. The first inner connecting section is bent inwards and arranged at one end of the first middle connecting section and is fixedly connected to the first inner ring. The first outer connecting section is bent outwards and arranged at the other end of the first middle connecting section and is fixedly connected to the first outer ring. The first middle connecting section is located in the gap between the first inner ring and the first outer ring;

[0013] The second planar spring includes a second inner ring located on the inner layer, a second outer ring located on the outer layer, and at least three second elastic S-shaped connecting arms that are evenly distributed in the circumferential direction and are elastically connected between the second inner ring and the second outer ring. The second inner ring is fixedly connected to the other side of the installation ring. The second outer ring is fixedly connected to the inner wall of the housing. The second elastic S-shaped connecting arm includes a second inner connecting section, a second middle connecting section, and a second outer connecting section. The second inner connecting section is bent inwards and arranged at one end of the second middle connecting section and is fixedly connected to the second inner ring. The second outer connecting section is bent outwards and arranged at the other end of the second middle connecting section and is fixedly connected to the second outer ring. The second middle connecting section is located in the gap between the second inner ring and the second outer ring; The spring washer is fixedly clamped between the first outer ring and the second outer ring. Through the structural design of the first planar spring and the second planar spring, the magnetic conduction skeleton is effectively elastically vibrated and connected to the middle part of the inner side of the housing. Among them, the structures of the evenly distributed first elastic S-shaped connecting arms and the second elastic S-shaped connecting arms not only play an elastic connection role but also play a role in restricting the radial movement of the magnetic conduction skeleton, thereby preventing the magnetic conduction skeleton from tilting and shifting during vibration.

[0014] Preferably, the first inner ring, the installation ring, and the second inner ring are connected by at least three evenly distributed inner connecting screws. The inner connecting screws sequentially pass through the first inner ring, the installation ring, and the second inner ring and are locked and fixed to the other side of the second inner ring through inner connecting nuts. This fixed connection method is only one form of the existing common fixed connection structures, and fixed connection can also be achieved through other conventional fixed methods, such as welding, clamping, or bonding fixation, etc.

[0015] Preferably, the outer housing includes a first cylindrical housing and a second cylindrical housing which are symmetrically arranged. Both the first cylindrical housing and the second cylindrical housing are semi-closed structures with opposite openings. An inner end face of the opening of the first cylindrical housing is recessed to form a first annular step surface, and an inner end face of the opening of the second cylindrical housing is recessed to form a second annular step surface. The first outer ring, the spring washer, and the second outer ring are all embedded in the gap between the first annular step surface and the second annular step surface. At least six first long through holes that penetrate axially are circumferentially distributed inside the side wall of the first cylindrical housing. An inner end opening of the first long through hole is located on the first annular step surface. A second long through hole corresponding to the first long through hole in terms of quantity and position penetrates axially inside the side wall of the second cylindrical housing. An inner end opening of the second long through hole is located on the second annular step surface. A first outer connection hole corresponding to the first long through hole in terms of quantity and position is formed on the first outer ring. A second outer connection hole corresponding to the second long through hole in terms of quantity and position is formed on the second outer ring. The spring washer is provided with washer positioning holes corresponding to the first long through hole in terms of quantity and position. The first cylindrical housing and the second cylindrical housing are fixedly connected by screwing and locking with connection long screws corresponding to the first long through holes and corresponding outer connection nuts. The connection long screws extend from one end of the first cylindrical housing and sequentially pass through the first long through hole, the first outer connection hole, the washer positioning hole, the second outer connection hole, and the second long through hole, and are locked and fixed with the outer connection nuts at the other end of the second cylindrical housing. The first cylindrical housing and the second cylindrical housing are arranged oppositely in a symmetrical form. During installation, the first outer ring, the spring washer, and the second outer ring can be very conveniently embedded inside the gap between the first annular step surface and the second annular step surface and fixed by the connection long screws. When fixing, the connection long screws sequentially pass through the first long through hole, the first outer connection hole, the washer positioning hole, the second outer connection hole, and the second long through hole to lock the positions of each internal structure. After the outer connection nuts lock and fix the connection long screws, the spring washer is fixedly clamped between the first outer ring and the second outer ring to ensure the fixed position of the outer layer of the first planar spring and the second planar spring. Description of the Drawings

[0016] Figure 1 Schematic diagram of the external structure of Embodiment 1;

[0017] Figure 2 Partial structural cross-sectional view of Embodiment 1;

[0018] Figure 3 Partial structural diagram of Embodiment 1;

[0019] Figure 4 Explosion structure diagram of Example 2;

[0020] Figure 5 Assembly combination diagram of partial structures of Example 2;

[0021] Figure 6 Schematic structural diagram of the first planar spring in Example 2;

[0022] Figure 7 Simulated magnetic field distribution diagram of the device applying Example 2;

[0023] Figure 8 Output voltage waveform diagram of the device of Example 1 in Example 2.

[0024] Explanation of reference numerals in the drawings:

[0025] 1. Outer housing; 11. First cylindrical housing; 12. Second cylindrical housing; 13. First annular step surface; 14. Second annular step surface; 15. First long through hole; 16. Second long through hole;

[0026] 2. Magnetic conduction skeleton; 21. First annular magnet; 22. Second annular magnet; 23. Mounting ring; 24. First annular mounting groove; 25. Second annular mounting groove;

[0027] 31. First annular induction coil; 32. Second annular induction coil; 33. First coil bracket; 34. First mounting screw; 35. First mounting nut; 36. Second coil bracket; 37. Second mounting screw; 38. Second mounting nut;

[0028] 41. Spring washer; 411. Washer positioning hole; 42. First inner ring; 43. First outer ring; 431. First outer connection hole; 44. First elastic S-shaped connecting arm; 441. First inner connecting section; 442. First middle connecting section; 443. First outer connecting section; 45. Second inner ring; 46. Second outer ring; 461. Second outer connection hole; 47. Second elastic S-shaped connecting arm; 471. Second inner connecting section; 472. Second middle connecting section; 473. Second outer connecting section; 48. Inner connecting screw; 49. Inner connecting nut;

[0029] 51. Connecting long screw; 52. Outer connecting nut. Detailed implementation manners

[0030] The present invention will be further described in detail below in conjunction with the embodiments in the drawings.

[0031] Example 1: As shown in Figures 1 to 3As shown in the figure, a differential dual-output electromagnetic vibration energy harvesting device includes a housing 1, a vibration mechanism, and an induction mechanism. The vibration mechanism includes a magnetic conductive framework 2, a first annular magnet 21, and a second annular magnet 22. The induction mechanism includes a first annular induction coil 31 and a second annular induction coil 32 whose ends both extend out of the housing 1. The first annular induction coil 31 is fixedly connected to one end of the housing 1 through a first coil support 33. The first coil support 33 is fixedly connected to one end of the housing 1 through the cooperation and locking between a first mounting screw 34 and a first mounting nut 35. The second annular induction coil 32 is fixedly connected to the other end of the housing 1 through a second coil support 36. The second coil support 36 is fixedly connected to the other end of the housing 1 through the cooperation and locking between a second mounting screw 37 and a second mounting nut 38. The arrangements of the first coil support 33 and the second coil support 36 facilitate the installation of the first annular induction coil 31 and the second annular induction coil 32 and the maintenance, replacement, or adjustment after disassembly. The magnetic conductive framework 2 is elastically connected along the axial direction and vibrates inside the middle part of the housing 1 through an elastic connection mechanism. The elastic connection mechanism includes a first planar spring, a second planar spring, and a spring washer 41. The first planar spring is elastically connected between the outer side of the magnetic conductive framework 2 and the inner wall of the housing 1 and is perpendicular to the axial direction of the magnetic conductive framework 2 when at rest. The second planar spring is elastically connected between the outer side of the magnetic conductive framework 2 and the inner wall of the housing 1 and is perpendicular to the axial direction of the magnetic conductive framework 2 when at rest. The first planar spring includes a first inner ring 42 located in the inner layer, a first outer ring 43 located in the outer layer, and three first elastic S-shaped connecting arms 44 that are evenly distributed along the circumferential direction and elastically connect the first inner ring 42 and the first outer ring 43. An installation ring 23 is fixedly arranged around the middle part of the outer side of the magnetic conductive framework 2. The installation ring 23 is processed in a way of being integrally formed with the magnetic conductive framework 2 here, or can be separately formed and then clamped on the middle part of the outer side of the magnetic conductive framework 2. The first inner ring 42 is fixedly connected to one side of the installation ring 23, and the first outer ring 43 is fixedly connected to the inner wall of the housing 1. The second planar spring includes a second inner ring 45 located in the inner layer, a second outer ring 46 located in the outer layer, and three second elastic S-shaped connecting arms 47 that are evenly distributed along the circumferential direction and elastically connect the second inner ring 45 and the second outer ring 46. The second inner ring 45 is fixedly connected to the other side of the installation ring 23, and the second outer ring 46 is fixedly connected to the inner wall of the housing 1. The first inner ring 42, the installation ring 23, and the second inner ring 45 are connected by three evenly distributed inner connecting screws 48. The inner connecting screws 48 sequentially pass through the first inner ring 42, the installation ring 23, and the second inner ring 45 and are locked and fixed to the other side of the second inner ring 45 through an inner connecting nut 49. The spring washer 41 is fixedly clamped between the first outer ring 43 and the second outer ring 46. Among them, the number of the first elastic S-shaped connecting arms 44, the second elastic S-shaped connecting arms 47, and the inner connecting screws 48 can be designed to be more than three according to actual needs.

[0032] On both sides of the magnetic conductive skeleton 2 along the axial direction, symmetric depressions are respectively formed to form a first annular mounting groove 24 and a second annular mounting groove 25 that are separated from each other. The first annular magnet 21 is fixedly sleeved on the inner groove wall of the first annular mounting groove 24 and the magnetization direction is radial. The first annular induction coil 31 is fixedly arranged at one end of the outer housing 1 and extends into the first annular mounting groove 24 in a non-contact manner. The second annular magnet 22 is fixedly sleeved on the inner groove wall of the second annular mounting groove 25 and the magnetization direction is radial. The second annular induction coil 32 is fixedly arranged at the other end of the outer housing 1 and extends into the second annular mounting groove 25 in a non-contact manner. The height of the first annular magnet 21 is less than the height of the inner groove wall of the first annular mounting groove 24, and the height of the second annular magnet 22 is less than the height of the inner groove wall of the second annular mounting groove 25, ensuring that the first annular magnet 21 and the second annular magnet 22 will not directly collide with the first coil bracket 33 and the second coil bracket 36 during the vibration process, causing structural changes or damage. The magnetization directions of the first annular magnet 21 and the second annular magnet 22 are radial. Compared with axial magnetization, a more uniform magnetic field can be generated, while shortening the magnetic circuit length and reducing energy loss. By combining the magnetic conductive skeleton 2 with magnetism and the first annular magnet 21 and the second annular magnet 22 with radial magnetization, the magnetic circuit structure is closed, the magnetic flux leakage is reduced, and the energy capture efficiency of the overall device is improved.

[0033] The outer housing 1 includes a first cylindrical housing 11 and a second cylindrical housing 12 which are symmetrically arranged. Both the first cylindrical housing 11 and the second cylindrical housing 12 are semi-closed structures with opposite openings. An inner end face of the opening of the first cylindrical housing 11 is recessed to form a first annular step surface 13, and an inner end face of the opening of the second cylindrical housing 12 is recessed to form a second annular step surface 14. The first outer ring 43, the spring washer 41 and the second outer ring 46 are all embedded in the gap between the first annular step surface 13 and the second annular step surface 14. Six first long through holes 15 which penetrate axially are circumferentially distributed inside the side wall of the first cylindrical housing 11. The inner end opening of the first long through hole 15 is located on the first annular step surface 13. A second long through hole 16 which penetrates axially is provided inside the side wall of the second cylindrical housing 12, and the number and positions of the second long through holes 16 correspond to those of the first long through holes 15. The inner end opening of the second long through hole 16 is located on the second annular step surface 14. First outer connection holes 431 with the number and positions corresponding to those of the first long through holes 15 are formed in the first outer ring 43. Second outer connection holes 461 with the number and positions corresponding to those of the second long through holes 16 are formed in the second outer ring 46. Washer positioning holes 411 with the number and positions corresponding to those of the first long through holes 15 are formed in the spring washer 41. The first cylindrical housing 11 and the second cylindrical housing 12 are fixedly connected by screwing and locking between connection long screws 51 corresponding to the first long through holes 15 and corresponding outer connection nuts 52. The connection long screw 51 extends from one end of the first cylindrical housing 11 and sequentially passes through the first long through hole 15, the first outer connection hole 431, the washer positioning hole 411, the second outer connection hole 461 and the second long through hole 16, and is locked and fixed with the outer connection nut 52 at the other end of the second cylindrical housing 12. Among them, the number of the first long through holes 15 is designed to be six or more according to actual needs.

[0034] The first cylindrical housing 11 and the second cylindrical housing 12 are oppositely arranged in a symmetric form. During installation, the first outer ring 43, the spring washer 41 and the second outer ring 46 can be very conveniently embedded into the gap between the first annular step surface 13 and the second annular step surface 14 and fixed by the connection long screw 51. When fixing, the connection long screw 51 sequentially passes through the first long through hole 15, the first outer connection hole 431, the washer positioning hole 411, the second outer connection hole 461 and the second long through hole 16 to lock the positions of the internal structures. After the outer connection nut 52 locks and fixes the connection long screw 51, the spring washer 41 is fixedly clamped between the first outer ring 43 and the second outer ring 46 to ensure the fixed positions of the outer layers of the first planar spring and the second planar spring.

[0035] The working principle of the above Embodiment 1 is as follows:

[0036] The magnetic conduction framework 2 is elastically connected to the middle part inside the outer housing 1 along the axial direction through an elastic connection mechanism. Taking the equilibrium position as the reference plane, when vibrating, the magnetic conduction framework 2 drives the first annular magnet 21 to move towards the reference plane, while the second annular magnet 22 moves away from the reference plane, thus forming two differential alternating magnetic fields. The first annular induction coil 31 and the second annular induction coil 32 are respectively fixed at the two ends of the outer housing 1. The moving first annular magnet 21 and second annular magnet 22 respectively cut the corresponding first annular induction coil 31 and second annular induction coil 32, thereby generating two differential alternating voltages and outputting them from the ends of the first annular induction coil 31 and the second annular induction coil 32 to the outside of the outer housing 1, completing the energy harvesting process of converting vibration energy into electrical energy.

[0037] Embodiment 2: As Figures 4 to 6 shown, the rest is the same as Embodiment 1. The difference lies in that the first elastic S-shaped connecting arm 44 includes a first inner connecting section 441, a first middle connecting section 442, and a first outer connecting section 443. The first inner connecting section 441 is bent inward and arranged at one end of the first middle connecting section 442 and fixedly connected to the first inner ring 42. The first outer connecting section 443 is bent outward and arranged at the other end of the first middle connecting section 442 and fixedly connected to the first outer ring 43. The first middle connecting section 442 is located in the gap between the first inner ring 42 and the first outer ring 43. The second elastic S-shaped connecting arm 47 includes a second inner connecting section 471, a second middle connecting section 472, and a second outer connecting section 473. The second inner connecting section 471 is bent inward and arranged at one end of the second middle connecting section 472 and fixedly connected to the second inner ring 45. The second outer connecting section 473 is bent outward and arranged at the other end of the second middle connecting section 472 and fixedly connected to the second outer ring 46. The second middle connecting section 472 is located in the gap between the second inner ring 45 and the second outer ring 46. The uniformly distributed structures of the first elastic S-shaped connecting arms 44 and the second elastic S-shaped connecting arms 47 not only play the role of elastic connection but also play the role of restricting the movement of the magnetic conduction framework 2 in the radial direction, thereby preventing the magnetic conduction framework 2 from tilting and shifting during vibration.

[0038] Figure 7 Shown is the magnetic field distribution after the magnetic conduction framework 2, the first annular magnet 21, and the second annular magnet 22 are fixedly connected and simulated on the COMSOL software platform. It can be clearly seen that the magnetic force lines between the gaps are evenly and densely distributed, effectively shortening the magnetic circuit. The coil can vertically cut the magnetic force lines, maximizing the output effect of electromagnetic induction.

[0039] Example 1:

[0040] Figure 8The figure shows the waveform diagrams of the output voltages induced by the first annular induction coil 31 and the second annular induction coil 32 when the differential dual-output electromagnetic energy harvesting device is operating during experiments. The amplitudes of the voltage waveforms of the dual-output are equal and have a phase difference of exactly 180 degrees. In this first example, the basic parameters of the device are as follows: the axial lengths of the first cylindrical housing 11 and the second cylindrical housing 12 are 22 mm, the outer diameters are 52 mm, and the total external volume of the first cylindrical housing 11 and the second cylindrical housing 12 is 93.4 cm 3 ; the wire diameters of both the first annular induction coil 31 and the second annular induction coil 32 are 0.2 mm, the coil internal resistances of both the first annular induction coil 31 and the second annular induction coil 32 are 23.8 Ω, the number of turns of both the first annular induction coil 31 and the second annular induction coil 32 are 520, the resonance frequencies of both the first annular induction coil 31 and the second annular induction coil 32 are 76.05 Hz. When the vibration acceleration is 0.3 m / s 2 , the maximum open-circuit voltage output is 3.3 V. The measured output power is the largest when the load is 200 Ω, which is 7.5×2 mW, and the power density can reach 1.78 mW / cm 3 / g 2 . Compared with the power densities of the electromagnetic energy harvesting devices of researchers at home and abroad, it has a leading level. For example, in the paper "Leicht J, Manoli Y. A 2.6μW–1.2mW Autonomous Electromagnetic Vibration Energy Harvester Interface IC with Conduction-Angle-Controlled MPPT and up to 95% Efficiency[J]. IEEE Journal of Solid-State Circuits, 2017, 52(9):2448-2462." published by Joachim Leicht et al. in 2017, the maximum power density of the electromagnetic energy harvesting device can reach: 0.06 mW / cm 3 / g 2 ; in the paper "Sun Jianchao, Zhou Qiang, Wei Tianliu, et al. Research and Design of a High-Efficiency Vibration-Electromagnetic Energy Harvester Based on a Vertically Moving Magnet[J]. Foreign Electronic Measurement Technology, 2022, 41(11):78-87." published by Sun Jianchao et al. in 2022, the power density of the electromagnetic energy harvesting device is: 0.96 mW / cm 3; In the paper "Hou X, et al. Electromagnetic Energy Harvester Based on Bidirectional Vibration to Unidirectional Rotation Conversion for Environmental Low-Frequency Vibration Energy Harvesting[J]. IEEE Transactions on Power Electronics, 2024, 39(2): 1932-1941." published by Hou et al. in 2024, the power density of the electromagnetic energy harvesting device is: 0.56 mW / cm 3 / g 2 ; This shows that the differential dual-output electromagnetic vibration energy harvesting device in this Example 1 has a high power density, can achieve induced voltages with opposite phases and the same amplitudes for dual outputs, and has good dual-output characteristics.

Claims

1. A differential dual-output electromagnetic vibration energy harvesting device, characterized in that It includes a housing, a vibration mechanism and an induction mechanism. The vibration mechanism includes a magnetic conduction skeleton, a first annular magnet and a second annular magnet. The induction mechanism includes a first annular induction coil and a second annular induction coil with ends both extending out of the housing. The magnetic conduction skeleton is elastically connected to the middle part of the inner side of the housing along the axial direction through an elastic connection mechanism and elastically vibrates along the axial direction. Symmetric depressions are respectively formed on both sides of the magnetic conduction skeleton along the axial direction to form a mutually separated first annular installation groove and a second annular installation groove. The first annular magnet is fixedly sleeved on the inner groove wall of the first annular installation groove and the magnetization direction is radial. The first annular induction coil is fixedly arranged at one end of the housing and non-contactingly extends into the first annular installation groove. The second annular magnet is fixedly sleeved on the inner groove wall of the second annular installation groove and the magnetization direction is radial. The second annular induction coil is fixedly arranged at the other end of the housing and non-contactingly extends into the second annular installation groove. The elastic connection mechanism includes a first flat spring, a second flat spring and a spring washer. The first flat spring is elastically connected between the outer side of the magnetic conduction skeleton and the inner wall of the housing and is perpendicular to the axial direction of the magnetic conduction skeleton when at rest. The second flat spring is elastically connected between the outer side of the magnetic conduction skeleton and the inner wall of the housing and is perpendicular to the axial direction of the magnetic conduction skeleton when at rest. The spring washer is fixedly clamped between the outer layer of the first flat spring and the outer layer of the second flat spring. The first flat spring includes a first inner ring located at the inner layer, a first outer ring located at the outer layer, and at least three first elastic S-shaped connecting arms evenly distributed in the circumferential direction and elastically connected between the first inner ring and the first outer ring. An installation ring is fixedly arranged around the middle part of the outer side of the magnetic conduction skeleton. The first inner ring is fixedly connected to one side of the installation ring. The first outer ring is fixedly connected to the inner wall of the housing. The first elastic S-shaped connecting arm includes a first inner connecting section, a first middle connecting section and a first outer connecting section. The first inner connecting section is bent inwards and arranged at one end of the first middle connecting section and fixedly connected to the first inner ring. The first outer connecting section is bent outwards and arranged at the other end of the first middle connecting section and fixedly connected to the first outer ring. The first middle connecting section is located in the gap between the first inner ring and the first outer ring. The second planar spring described above includes a second inner ring located on the inner layer, a second outer ring located on the outer layer, and at least three second elastic S-shaped connecting arms that are evenly distributed in the circumferential direction and are elastically connected between the second inner ring and the second outer ring. The second inner ring is fixedly connected to the other side of the mounting ring, and the second outer ring is fixedly connected to the inner wall of the outer housing. The second elastic S-shaped connecting arm includes a second inner connecting section, a second middle connecting section, and a second outer connecting section. The second inner connecting section is bent inward and disposed at one end of the second middle connecting section and is fixedly connected to the second inner ring. The second outer connecting section is bent outward and disposed at the other end of the second middle connecting section and is fixedly connected to the second outer ring. The second middle connecting section is located in the gap between the second inner ring and the second outer ring. The spring washer is fixedly clamped between the first outer ring and the second outer ring.

2. The differential dual-output electromagnetic vibration energy harvesting device according to claim 1, characterized in that The first annular induction coil is fixedly connected to one end of the outer housing through a first coil bracket. The first coil bracket is fixedly connected to one end of the outer housing through the cooperation and locking between a first mounting screw and a first mounting nut. The second annular induction coil is fixedly connected to the other end of the outer housing through a second coil bracket. The second coil bracket is fixedly connected to the other end of the outer housing through the cooperation and locking between a second mounting screw and a second mounting nut.

3. A differential dual-output electromagnetic vibration energy harvesting device according to claim 2, characterized in that The height of the first annular magnet is less than the height of the inner groove wall of the first annular mounting groove, and the height of the second annular magnet is less than the height of the inner groove wall of the second annular mounting groove.

4. A differential dual-output electromagnetic vibration energy harvesting device according to claim 1, characterized in that The first inner ring, the mounting ring, and the second inner ring are connected by at least three evenly distributed inner connecting screws. The inner connecting screws sequentially pass through the first inner ring, the mounting ring, and the second inner ring and are locked and fixed to the other side of the second inner ring through inner connecting nuts.

5. The differential dual-output electromagnetic vibration energy harvesting device according to claim 4, characterized in that The described outer housing includes a first cylindrical housing and a second cylindrical housing which are symmetrically arranged. Both the first cylindrical housing and the second cylindrical housing are semi-closed structures with opposite openings. An inner end face of the opening of the first cylindrical housing is recessed to form a first annular step surface, and an inner end face of the opening of the second cylindrical housing is recessed to form a second annular step surface. The first outer ring, the spring washer, and the second outer ring are all embedded in the gap between the first annular step surface and the second annular step surface. At least six first long through holes that penetrate axially are circumferentially distributed inside the side wall of the first cylindrical housing. An inner end opening of the first long through hole is located on the first annular step surface. A second long through hole that penetrates axially is provided inside the side wall of the second cylindrical housing, and the number and position of the second long through hole correspond to those of the first long through hole. An inner end opening of the second long through hole is located on the second annular step surface. First outer connection holes with the same number and position as the first long through holes are formed on the first outer ring. Second outer connection holes with the same number and position as the second long through holes are formed on the second outer ring. Washer positioning holes with the same number and position as the first long through holes are formed on the spring washer. The first cylindrical housing and the second cylindrical housing are fixedly connected by screwing and locking with connection long screws corresponding to the first long through holes and corresponding outer connection nuts. The connection long screws extend from one end of the first cylindrical housing and sequentially pass through the first long through holes, the first outer connection holes, the washer positioning holes, the second outer connection holes, and the second long through holes, and are locked and fixed with the outer connection nuts at the other end of the second cylindrical housing.

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