Electromagnetic type two-degree-of-freedom vibration energy collector based on plane spring

Abstract

The invention discloses an electromagnetic type two-degree-of-freedom vibration energy collector based on a plane spring. The electromagnetic type two-degree-of-freedom vibration energy collector comprises a cover, a shell, a magnetic induction power generation module and an excitation module. The shell is a hollow cylinder, internal threads are arranged at two ends of the shell, openings at the upper end and the lower end are identical with the diameter of the plane spring, the magnetic induction module is placed at the top of the shell, the excitation module is placed at the bottom of the shell, and two ends of the cylindrical shell are sealed through two identical cover threads. The invention overcomes the defect that the output performance of a single-degree-of-freedom collector is sharply reduced when the external excitation frequency deviates from the resonant frequency, and is suitable for a vibration environment with a wide frequency range.

Description

Technical Field

[0001] The invention belongs to the technical field of self-generation, and in particular is an electromagnetic double-degree-of-freedom vibration energy collector based on a plane spring. Background Art

[0002] In the past few decades, with the rapid development of wireless sensor networks, the number of sensor nodes has increased exponentially, and people's requirements for the reliability and durability of power supply for sensor nodes are also increasing. Traditional batteries have problems such as environmental impact, limited battery life and limited capacity. This has led many researchers to turn their research perspectives to obtaining energy from the surrounding environment of sensor nodes, making sensor nodes self-sufficient in electricity, thereby greatly improving the service life of the entire wireless sensor network and significantly reducing the maintenance costs of the system.

[0003] Ways to collect energy from the surrounding environment include solar energy, thermal energy, vibration energy, etc. Compared with other environmental energies, vibration energy is more common in industry, human body, and transportation. There are three main ways to harvest vibration energy: electromagnetic, electrostatic, and piezoelectric. Compared with the other two vibration energy harvesting methods, the electromagnetic method has the advantages of simple structure and higher output power. Traditional electromagnetic vibration energy harvesters usually have a single resonant frequency, but the external excitation frequency equal to its resonant frequency can achieve the maximum displacement and the maximum harvested power. However, when the external excitation frequency deviates from the resonant frequency, the harvested power drops sharply. The actual vibration in the environment always has a wide dynamic range. How to apply it to complex vibration environments, how to improve energy harvesting efficiency, and how to eliminate the friction of the internal structure of the harvester during vibration have become technical difficulties for self-powered. Summary of the invention

[0004] In response to the above problems, the present invention provides a design of an electromagnetic dual-degree-of-freedom vibration energy harvester based on a planar spring. The harvester can overcome the problem that traditional electromagnetic single-degree-of-freedom vibration energy harvesters cannot efficiently collect vibration energy in complex and changeable vibration environments. It can effectively collect energy in a wider frequency range and also make the assembly of the harvester more convenient.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an electromagnetic dual-degree-of-freedom vibration energy harvester based on a planar spring, comprising a cover, a shell, a magnetic induction power generation module and an excitation module; the shell is a hollow cylinder with internal threads at both ends, the openings at the upper and lower ends are the same size as the diameter of the planar spring, the magnetic induction module is placed on the top of the shell, the excitation module is placed on the bottom of the shell, and the two ends of the cylindrical shell are sealed by two identical cover threads.

[0006] The magnetic induction power generation module includes: bolts, upper plane springs, hot melt nuts, coil brackets and coil windings. The hot melt nuts are embedded in the winding brackets made of resin materials; the coil windings are wound in the grooves of the winding brackets; the bolts pass through the central circular hole of the upper plane springs and are screwed into the hot melt nuts in the winding brackets, and the upper plane springs are fixed to the bottom of the internal threads at the upper end of the shell. The excitation module includes: nuts, upper magnets, ferromagnetic gaskets, lower magnets, magnet brackets, lower plane springs and bolts. The upper magnet and the lower magnet are annular magnets of the same size and opposite polarities; a ferromagnetic gasket is used between the two annular magnets to adsorb the two annular magnets together to form an upper magnet-ferromagnetic gasket-lower magnet combination; the magnet bracket passes through the upper magnet-ferromagnetic gasket-lower magnet combination, the central through hole of the magnet bracket is aligned with the central circular hole of the lower plane spring, the bolts are passed through the central circular hole of the lower plane spring and the central through hole of the magnet bracket, and the nuts are used to fix the excitation module.

[0007] Preferably, the spring is a planar spring.

[0008] The material used for the planar spring is 65Si2Mn. The upper planar spring is composed of four serpentine sectors, and the lower planar spring is composed of three serpentine sectors.

[0009] The material used for the winding bracket is resin, the lower part of the winding bracket is a groove, the middle part is a hollow cylinder, and the top is a hollow cylinder with a diameter smaller than the middle part. The inner diameter of the winding bracket is larger than the diameter of the magnet, which is conducive to placing the coil winding with a very small distance from the magnet to improve the magnetic induction intensity in the coil winding, so that the present invention can obtain a larger induced voltage;

[0010] Preferably, the magnet bracket is used to fix the upper magnet-ferromagnetic gasket-lower magnet combination on the lower plane spring. The bottom of the magnet bracket is a hollow cylinder to prevent the excitation module from colliding and rubbing with the lower plane spring during vibration. There is a circular through hole in the middle of the magnet bracket for passing the bolt.

[0011] Preferably, the shell is a hollow cylinder, and is made by cutting and setting internal threads at both ends. The openings at the upper and lower ends are the same size as the diameter of the plane spring, which is conducive to fixing the plane spring and avoiding lateral displacement of the plane spring. There is a small hole in the middle of the shell, which can lead out the coil to collect energy for use in the next stage. The cover can be screwed into the shell to fix the plane spring and avoid longitudinal displacement of the plane spring.

[0012] The present invention uses Faraday's electromagnetic law. After being externally excited, the device will generate forced vibration, the permanent magnet and the coil winding will move relative to each other, and the magnetic flux in the coil winding will also begin to change, so that the coil winding generates an induced voltage. According to the principle, the greater the amplitude of the relative motion, the greater the induced voltage generated. A coil winding with a very small distance from the permanent magnet can be placed inside the structure to increase the magnetic induction intensity in the coil winding, so that the present invention can obtain a larger induced voltage.

[0013] The present invention has a simple structure and is easy to assemble. It only requires core components such as a plane spring, a coil winding, a winding bracket, a permanent magnet, and a ferromagnetic gasket, and is suitable for vibration energy collection in a wide frequency range.

[0014] Compared with other electromagnetic collectors, the present invention can adjust the two resonant frequencies of the dual-degree-of-freedom collector by changing the stiffness of the upper and lower plane springs, and can be applied to different scenarios to obtain the best output characteristics. Secondly, the parts of the collector can all be made according to 3D printing, which reduces the production cost of the equipment and facilitates mass production.

[0015] The beneficial effects of the present invention are:

[0016] 1. The magnetic induction power generation module and the excitation module have their own resonant angular frequency when they are stimulated by the outside world. and , which overcomes the shortcoming of a single-degree-of-freedom collector that its output performance drops sharply when the external excitation frequency deviates from the resonant frequency, and is suitable for vibration environments with a wide frequency range.

[0017] 2. Use an excitation module consisting of an upper magnet, a ferromagnetic gasket, and a lower magnet. The repelling magnets fit together to weaken the axial magnetic field strength and increase the longitudinal magnetic field strength. The ferromagnetic gasket in the middle eliminates the repulsive force between the magnets and can increase the radial magnetic induction strength, thereby improving the output performance of the collector.

[0018] 3. The planar spring structure ensures that the magnets and coils moving inside only move axially, avoiding collision and friction between the internal structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the decomposition of the present invention;

[0020] Figure 2 is a cross-sectional view of the present invention;

[0021] Figure 3 It is the top view of the upper plane spring;

[0022] Figure 4 It is the top view of the lower plane spring;

[0023] Figure 5It is the 3D diagram of the plane spring;

[0024] Figure 6 It is a side view of the magnetic induction power generation module;

[0025] Figure 7 It is the side view of the coil support;

[0026] Figure 8 It is the side view of the excitation module;

[0027] Fig. 9 It is a side view of the magnet bracket;

[0028] Fig.10 It is a schematic diagram of the upper magnet-ferromagnetic gasket-lower magnet combination;

[0029] Fig.11 This is a schematic diagram of the collector housing;

[0030] Fig.12 This is a schematic diagram of the collector cover;

[0031] Fig.13 This is the output voltage waveform diagram of the present invention. DETAILED DESCRIPTION

[0032] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0033] like Figure 1 and Figure 2 As shown, an electromagnetic dual-degree-of-freedom vibration energy harvester based on a planar spring comprises a cover 1, a shell 2, a magnetic induction power generation module and an excitation module; the shell 2 is a hollow cylinder with internal threads at both ends, the openings at the upper and lower ends are the same size as the diameter of the planar spring, the magnetic induction module is placed on the top of the shell 2, the excitation module is placed on the bottom of the shell 2, and the two ends of the cylindrical shell 2 are sealed by two identical cover 1 threads.

[0034] The magnetic induction power generation module includes: bolt 3, upper plane spring 4, hot melt nut 5, coil support 6 and coil winding 7. The hot melt nut 5 is embedded in the winding support 6 made of resin material; the coil winding 7 is wound in the groove of the winding support 6, with a total of 2500 turns; the bolt 3 passes through the central circular hole of the upper plane spring 4, screws into the hot melt nut 5 in the winding support 6, and the upper plane spring 4 is fixed to the bottom of the internal thread at the upper end of the shell 2. The excitation module includes: nut 8, upper magnet 9, ferromagnetic gasket 10, lower magnet 11, magnet support 12, lower plane spring 13 and bolt 14. The upper magnet 9 and the lower magnet 11 are annular magnets with an inner diameter of 10 mm, an outer diameter of 30 mm, a thickness of 10 mm and opposite polarities; a ferromagnetic gasket with an inner diameter of 10 mm, an outer diameter of 30 mm and a thickness of 6 mm is used between the two annular magnets to adsorb the two annular magnets together to form an upper magnet 9-ferromagnetic gasket 10-lower magnet 11 combination; the magnet bracket 12 passes through the upper magnet 9-ferromagnetic gasket 10-lower magnet 11 combination, the central through hole of the magnet bracket is aligned with the central circular hole of the lower plane spring 13, the bolt 14 is passed through the central circular hole of the lower plane spring 13 and the central through hole of the magnet bracket 12, and the nut 8 is used to fix the excitation module.

[0035] Preferably, the spring is a planar spring.

[0036] The material used for the planar spring is 65Si2Mn. The upper planar spring 4 is composed of three serpentine sectors, and the lower planar spring 13 is composed of four serpentine sectors. The diameter of the two planar springs is 56 mm and the thickness is 0.8 mm.

[0037] The material used for the winding bracket 6 is resin. The lower part of the winding bracket 6 is a groove with an inner diameter of 35 mm, an outer diameter of 49 mm, and a height of 16 mm. The middle part is a hollow cylinder with a diameter of 38 mm and a height of 25 mm. The top is a hollow cylinder with an inner diameter of 8 mm, an outer diameter of 14 mm, and a height of 4 mm. The inner diameter of the winding bracket 6 is larger than the diameter of the magnet, which is conducive to placing the coil winding 7 with a very small distance from the magnet to improve the magnetic induction intensity in the coil winding 7, so that the present invention can obtain a larger induced voltage;

[0038] Preferably, the magnet bracket 12 is used to fix the upper magnet 9-ferromagnetic gasket 10-lower magnet 11 combination on the lower plane spring 13. The bottom of the magnet bracket 12 is a hollow cylinder with an inner diameter of 6 mm, an outer diameter of 14 mm, and a height of 4 mm to prevent the excitation module from colliding and rubbing with the lower plane spring 13 during vibration. There is a circular through hole in the middle of the magnet bracket for passing the bolt 14.

[0039] Preferably, the shell 2 is made of a hollow cylinder with an inner diameter of 54 mm, an outer diameter of 64 mm, and a height of 81 mm. Hollow cylinders with an inner diameter of 54 mm, an outer diameter of 56 mm, and a height of 12 mm are cut off at both ends and internal threads are set. The openings at the upper and lower ends are the same size as the diameter of the plane spring, which is conducive to fixing the plane spring and avoiding lateral displacement of the plane spring. There is a small hole in the middle of the shell 2, which can lead out the coil to collect energy for use in the next stage. The cover 1 can be screwed into the shell 2 to fix the plane spring and avoid longitudinal displacement of the plane spring.

[0040] Example:

[0041] An electromagnetic double-degree-of-freedom vibration energy harvester based on a plane spring, such as Figure 1 As shown, it includes a cover 1, a shell 2, a magnetic induction power generation module (including bolts 3, an upper plane spring 4, a hot melt nut 5, a winding bracket 6 and a coil winding 7), and an excitation module (including nuts 8, an upper magnet 9, a ferromagnetic gasket 10, a lower magnet 11, a magnet bracket 12, a lower plane spring 13 and bolts 14); the magnetic induction power generation module is fixed to the upper plane spring 4 by means of embedded hot melt nuts 5 and bolts 3, the upper plane spring 4 is placed in a slot of the same size as the shell 2 and fixed on all sides, and is fixed up and down using the cover 1; the excitation module uses a magnet bracket 12, a nut 8 and a bolt 14 to fix the upper magnet 9-ferromagnetic gasket 10-lower magnet 11 combination to the lower plane spring 13, the lower plane spring 13 is placed in a slot of the same size as the shell 2 and fixed on all sides, and is fixed up and down using the shell 1.

[0042] In this embodiment, Figure 3 , Figure 4 and Figure 5 As shown, the plane spring is made by laser cutting of 65Si2Mn. The upper plane spring 4 is designed as four serpentine cantilever beams, and the lower plane spring 13 is designed as three serpentine cantilever beams. The stiffness of the plane spring can be changed by changing the number, width, length and other parameters of the cantilever beams. The plane spring of this structure can ensure the axial movement of the moving block and avoid collision and friction between the moving blocks.

[0043] In this embodiment, Figure 6 , Figure 7 and Figure 8 As shown, the size of the winding bracket 6 is slightly larger than the diameter of the magnet block, so that when the magnetic induction power generation module and the excitation module move relative to each other, the coil winding 7 is as close to the magnet as possible, increasing the magnetic flux gradient, thereby improving the output performance. The winding bracket 6 is made of resin material 3D printing, can be embedded with a hot melt nut 5, and is fixed to the upper plane spring 4 by a bolt 3.

[0044] In this embodiment, Fig. 9 and Fig.10As shown, the upper magnet 9-ferromagnetic gasket 10-lower magnet 11 combination consists of two magnets with opposite polarities and a ferromagnetic gasket. The combination of permanent magnets with opposite polarities is conducive to weakening the axial magnetic field strength and increasing the longitudinal magnetic field strength; the ferromagnetic gasket is placed between the two permanent magnets, which is conducive to eliminating the repulsive force between the two, increasing the attractive force between the two, and can increase the radial magnetic induction intensity, thereby improving the output performance of the collector.

[0045] In this embodiment, Fig.11 and Fig.12 As shown, the size of the slot at the upper part of the shell 2 is the same as the diameter of the upper plane spring 4, the magnetic induction power generation module is placed in the slot, and the cover 1 is used to fix it up and down; the size of the slot at the lower part of the shell 2 is the same as the diameter of the lower plane spring 13, the excitation module is placed in the slot, and the cover 2 is used to fix it up and down.

[0046] The working principle and process are as follows: the upper plane spring 4, the winding support 6, and the coil winding 7 are the main components of the magnetic induction power generation module. According to the expression:

[0047]

[0048] The total weight of the winding support 6 and the coil winding 7 is , the elastic coefficient of the upper plane spring 4 is , when stimulated by external factors, the resonant angular frequency of the magnetic induction power generation module The lower plane spring 13, the upper magnet 9, the ferromagnetic gasket 10, the lower magnet 11 and the magnet bracket 12 are the main components of the excitation module. According to the above expression, the total weight of the upper magnet 9-ferromagnetic gasket 10-lower magnet 11 combination is , the elastic coefficient of the lower plane spring 13 is , when subjected to external excitation, the resonant angular frequency of the excitation module is The resonant angular frequency can be adjusted according to the application environment by adjusting the elastic coefficient k of the upper plane spring 4 and the lower plane spring 13 and , so that the performance of the electromagnetic dual-degree-of-freedom vibration energy harvester can be optimized.

[0049] The specific implementation steps of the entire structure are as follows:

[0050] Step 1: Use 3D printing technology to make the cover 1, the shell 2, the coil bracket 6 and the magnet bracket 12.

[0051] Step 2: Use laser cutting technology to make upper plane springs 4 and lower plane springs 13 with different stiffnesses.

[0052] Step 3: Purchase enameled wire and wind it on a coil support to form a coil winding 7.

[0053] Step 4: Purchase upper magnet 9, ferromagnetic gasket 10, lower magnet 11, hot melt nut 5, bolt 3, bolt 14, nut 8.

[0054] Step 5: System assembly.

[0055] Fig.13 This is the output voltage curve of the electromagnetic dual-degree-of-freedom vibration energy harvester as the external excitation frequency changes. When the external excitation frequency is equal to the two resonant frequencies of the harvester and When the external excitation deviates from the resonant frequency, the output voltage of the collector has two peaks. When the external excitation deviates from the resonant frequency, the collector still has a high collection efficiency. The electromagnetic dual-degree-of-freedom vibration energy harvester overcomes the defect that the output performance of the single-degree-of-freedom collector drops sharply when the external excitation frequency deviates from the resonant frequency. It can efficiently collect vibration energy in complex and changeable vibration environments and can effectively collect energy in a wider frequency range.

[0056] The above descriptions are only some specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. An electromagnetic double-degree-of-freedom vibration energy harvester based on a plane spring, characterized in that: It comprises a cover (1), a housing (2), a magnetic induction power generation module and an excitation module; The shell (2) is a hollow cylinder with internal threads at both ends. The openings at the upper and lower ends are the same size as the diameter of the plane spring. The magnetic induction module is placed on the top of the shell (2), and the excitation module is placed on the bottom of the shell (2). The two ends of the cylindrical shell (2) are sealed by threads of two identical covers (1).

2. The electromagnetic double-degree-of-freedom vibration energy harvester based on a plane spring according to claim 1 is characterized in that: The magnetic induction power generation module comprises: a bolt (3), an upper plane spring (4), a hot melt nut (5), a coil support (6) and a coil winding (7); The hot melt nut (5) is embedded in a winding support (6) made of resin material; the coil winding (7) is wound in a groove of the winding support (6); the bolt (3) passes through the central circular hole of the upper plane spring (4) and is screwed into the hot melt nut (5) in the winding support (6); the upper plane spring (4) is fixed to the bottom of the internal thread at the upper end of the housing (2).

3. The electromagnetic double-degree-of-freedom vibration energy harvester based on a plane spring according to claim 2 is characterized in that: The excitation module comprises: a nut (8), an upper magnet (9), a ferromagnetic gasket (10), a lower magnet (11), a magnet bracket (12), a lower plane spring (13) and a bolt (14); the upper magnet (9) and the lower magnet (11) are annular magnets of the same size and opposite polarities; a ferromagnetic gasket is used between the two annular magnets to adsorb the two annular magnets together, and from top to bottom they are the upper magnet (9), the ferromagnetic gasket (10) and the lower magnet (11); the magnet bracket (12) passes through the combination of the upper magnet (9), the ferromagnetic gasket (10) and the lower magnet (11), the central through hole of the magnet bracket is aligned with the central circular hole of the lower plane spring (13), the bolt (14) passes through the central circular hole of the lower plane spring (13) and the central through hole of the magnet bracket (12), and the nut (8) is used to fix the excitation module.

4. The electromagnetic double-degree-of-freedom vibration energy harvester based on a plane spring according to claim 3 is characterized in that: The upper plane spring (4) and the lower plane spring (13) are made of 65Si2Mn. The upper plane spring (4) is composed of four serpentine sectors, and the lower plane spring (13) is composed of three serpentine sectors.

5. The electromagnetic double-degree-of-freedom vibration energy harvester based on a plane spring according to claim 4 is characterized in that: The material used for the winding bracket (6) is resin. The lower part of the winding bracket (6) has a groove, the middle part is a hollow cylinder, the top part is a hollow cylinder with a diameter smaller than the middle part, and the inner diameter of the winding bracket (6) is larger than the diameter of the magnet.

6. The electromagnetic double-degree-of-freedom vibration energy harvester based on a plane spring according to claim 5 is characterized in that: The shell (2) has a small hole in the middle, which is used to lead out the coil to obtain the collected energy.

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