CN107359825B - Swing type multi-directional piezoelectric energy harvester - Google Patents

Abstract

The invention relates to a swinging multi-directional piezoelectric energy harvester, which belongs to the technical field of piezoelectric power generation. The housing is equipped with an upper cover, and the upper cover is equipped with a fixed magnetic piece and a limit ring; a circuit board and a floating magnet are installed on the bottom wall of the housing; The upper right boss and the lower right boss are arranged on the side wall; the two ends of the separator with the limit ring are installed on the left and right lower bosses; two piezoelectric vibrators and two spacers are installed on the left and right upper bosses, Two gaskets are sandwiched between two piezoelectric vibrators; the fixed sections at both ends of the reed are respectively crimped between the two gaskets on the left and right upper bosses, and the fixed sections of the reed are connected by a narrow spring The wide spring is equipped with two splints, a moving magnetic piece and an inertial block, the splints are symmetrically clamped on the upper and lower sides of the wide spring, and the moving magnetic piece is placed above the wide spring; the small diameter end of the T-shaped inertial block is fixed under the wide spring The splint and the large-diameter end are equipped with suspended magnets; the substrate of the piezoelectric vibrator is installed close to the gasket, and the free end leans against the splint.

Description

A swinging multi-directional piezoelectric energy harvester

technical field

The invention belongs to the technical field of piezoelectric power generation, and in particular relates to a swing-type multi-directional piezoelectric energy harvester for supplying power to a ship positioning and tracking system.

Background technique

The ship positioning and tracking system has been widely used on civil ships, providing a strong guarantee for the ship's navigation safety, timely rescue, and search and rescue after losing contact. However, the existing positioning and tracking systems are all based on engine power supply. Once an accident occurs on the ship and the engine and the entire power system fail, the positioning and tracking system will lose its proper function. In addition, the existing positioning and tracking systems are all external, and cannot work normally when the ship is wrecked and flooded, and the positioning system is easily shut down or destroyed after the ship is hijacked by criminals. In recent years, in order to ensure the safe and reliable operation of the ship positioning system, people have started to study self-powered devices based on piezoelectric materials, called piezoelectric generators or piezoelectric energy harvesters, so as to be integrated with the positioning system and installed secretly. However, most of the piezoelectric generators currently proposed for ship positioning and tracking systems are directly excited by the additional mass inertial force on the piezoelectric vibrator, so they can only collect energy in a fixed vibration direction and the resonant frequency is poorly adjustable; the most critical is The piezoelectric vibrator is subjected to two-way excitation and two-way bending deformation during operation. When the ship vibrates or shakes in the wind and waves with a large amplitude, the brittle piezoelectric material is easily broken due to excessive tensile stress. Therefore, in order to make the piezoelectric generator practically applied in the ship positioning and tracking system, the key problem that needs to be solved is to improve the adaptability and reliability of the vibration direction and the adjustability of the resonance frequency.

Contents of the invention

The present invention proposes a swinging multi-directional piezoelectric energy harvester. The embodiment adopted in the present invention is: the end of the side wall of the housing is provided with an upper cover through screws, and a fixed magnetic piece is installed on the lower surface of the upper cover through screws. And the limit ring, the material of the limit ring is rubber; the bottom wall of the housing is equipped with a circuit board and a suspension magnet through screws, and the suspension magnet is circular; the circuit board is equipped with an energy conversion circuit and a signal transmission system; the housing The left side wall of the housing is provided with a left upper boss and a left lower boss, and the right side wall of the housing is provided with a right upper boss and a right lower boss; the two ends of the partition are respectively installed on the left lower boss and the right lower boss On the stage, a through hole is arranged on the partition and a limiting ring is installed through screws.

Both the upper left boss and the upper right boss are installed with two piezoelectric vibrators and two spacers through the pressure plate and screws, and the two spacers are clamped between the fixed ends of the two piezoelectric vibrators; the fixed sections at both ends of the reed are respectively It is crimped between the two gaskets on the upper left boss and the upper right boss, and a wide spring is connected between the fixed sections at both ends of the reed through two narrow springs; two splints and a moving spring are installed on the wide spring through screws. The magnetic piece and an inertia block, two splints are sandwiched symmetrically on the upper and lower sides of the wide spring, the moving magnetic piece is placed above the wide spring and installed opposite to the same-sex magnetic pole of the fixed magnetic piece, and the diameter of the moving magnetic piece is smaller than the diameter of the fixed magnetic piece; The inertia block is a T-shaped structure. The end of the inertia block with a smaller diameter is fixed on the splint under the wide spring, and the end with a larger diameter is installed with a suspended magnet through a screw. The diameter of the suspension magnet is smaller than that of the suspension magnet.

其中：B＝1-α+αβ，A＝α⁴(1-β)²-4α³(1-β)+6α²(1-β)-4α(1-β)+1，

α＝h_m/H，β＝E_m/E_p，h_m为基板厚度，H为压电振子总厚度，E_m和E_p分别为基板和压电片材料的杨氏模量，k₃₁和

分别为压电材料的机电耦合系数和许用压应力，L为压电振子的悬臂长度。The piezoelectric vibrator is made by bonding the substrate and the piezoelectric sheet. The substrate is installed close to the gasket, and the free end of the piezoelectric vibrator is against the splint, but there is no interaction force between the two; the piezoelectric vibrator is a straight structure before and after installation. , the allowable bending deformation at the free end of the piezoelectric vibrator is

Among them: B=1-α+αβ, A=α ⁴ (1-β) ² -4α ³ (1-β)+6α ² (1-β)-4α(1-β)+1,

α=h _m /H, β=E _m /E _p , h _m is the thickness of the substrate, H is the total thickness of the piezoelectric vibrator, E _m and E _p are the Young's modulus of the substrate and the piezoelectric sheet material, k ₃₁ and

are the electromechanical coupling coefficient and the allowable compressive stress of the piezoelectric material, respectively, and L is the cantilever length of the piezoelectric vibrator.

In the non-working state, that is, when there is no vibration in the environment, the piezoelectric vibrator and the reed are in the original straight state without bending deformation; when there is vertical vibration in the environment, the inertia block drives the splint to vibrate up and down; when the environment When there is vibration in other directions, the inertia block drives the splint to swing; any position change of the splint will change the contact point between the splint and the piezoelectric vibrator, thereby changing the deformation of the piezoelectric vibrator and the stress distribution state on the piezoelectric sheet. During the change of the stress distribution state on the chip, the mechanical energy is converted into electrical energy; when the vibration or swing amplitude of the inertia block and the splint is large and the free end of the piezoelectric vibrator is close to but not in contact with the limit ring, the fixed magnet and the moving magnet The repulsive force between the sheets or the repulsive force between the suspended magnet and the suspended magnet has a buffering effect; when the free end of the piezoelectric vibrator is in contact with the limit ring, the deformation of the free end of the piezoelectric vibrator is less than its allowable value, thereby ensuring that the piezoelectric vibrator The maximum compressive stress on the sheet is less than its allowable value.

In the present invention, the deformation characteristics of the piezoelectric vibrator are jointly determined by the mass of the inertia block, the structural scale of the reed and the structural scale of the splint, so the fundamental frequency of the energy harvester is easily adjusted through the above-mentioned elements and parameters, so as to achieve the same frequency as the ship's pitching vibration frequency. matching; because the fundamental frequency of the piezoelectric vibrator itself is much higher than the pitching vibration frequency of the ship, the piezoelectric vibrator always works in the first-order mode, and the power generation effect is better; One-way excitation, and the excitation direction makes the piezoelectric sheet bear compressive stress, and when the piezoelectric vibrator relies on its own elastic force to restore deformation, there will be no tensile stress or less tensile stress on the piezoelectric sheet, so the reliability is high.

Advantages and features: It can collect the turbulence and vibration energy in any direction when the ship is sailing, and has strong environmental adaptability; the piezoelectric vibrator itself has no additional mass and has a high fundamental frequency, which can ensure that it works in the first-order mode, and the power generation effect is good, and The fundamental frequency of the system is easy to adjust through the inertia block and the scale of the reed structure; the piezoelectric vibrator only bears one-way excitation and produces one-way bending deformation during work, and the piezoelectric sheet only bears compressive stress or the tensile stress it bears is small, so the reliability high.

Description of drawings

Fig. 1 is a structural sectional view of an energy harvester in a preferred embodiment of the present invention;

Fig. 2 is A-A sectional view of Fig. 1;

Fig. 3 is a schematic structural diagram of a reed in a preferred embodiment of the present invention.

Detailed ways

The end of the side wall of the housing a is fitted with an upper cover b through screws, and the lower surface of the upper cover b is equipped with a fixed magnetic piece x and a limit ring z through screws. The material of the limit ring z is rubber; A circuit board c and a suspension magnet d are mounted on the bottom wall a1 via screws, and the suspension magnet d is circular; the circuit board c is provided with an energy conversion circuit and a signal transmission system; the left side wall a2 of the housing a is provided with a left upper convex platform a3 and left lower boss a4, right upper boss a3' and right lower boss a4' are arranged on the right side wall a2' of shell a; On the lower boss a4', a through hole is provided on the partition t and the limiting ring z is installed by screws.

Both the upper left boss a3 and the upper right boss a3' are installed with two piezoelectric vibrators f and two spacers g through the pressure plate e and screws, and the two spacers g are sandwiched between the fixed ends of the two piezoelectric vibrators f The fixed section h1 at both ends of the reed h is respectively crimped between the two spacers g on the upper left boss a3 and the upper right boss a3', and the fixed section h1 at both ends of the reed h is connected by two narrow springs h2 There is a wide spring h3; two splints i, a moving magnet y and an inertia block j are installed on the wide spring h3 via screws, and the two splints i are sandwiched symmetrically on the upper and lower sides of the wide spring h3, and the moving magnet y It is installed above the wide spring h3 and opposite to the same-sex magnetic pole of the fixed magnet piece x, the diameter of the moving magnet piece y is smaller than the diameter of the fixed magnet piece x; the inertia block j is a T-shaped structure, and the smaller diameter end of the inertia block j is fixed On the splint i under the wide spring h3, the end with a larger diameter is installed with a suspended magnet k through a screw, and the same-sex magnetic poles of the suspended magnet k and the suspended magnet d are oppositely installed, and the diameter of the suspended magnet k is smaller than that of the suspended magnet d. .

其中：B＝1-α+αβ，A＝α⁴(1-β)²-4α³(1-β)+6α²(1-β)-4α(1-β)+1，

α＝h_m/H，β＝E_m/E_p，h_m为基板f1的厚度，H为压电振子f总厚度，E_m和E_p分别为基板f1和压电片f2材料的杨氏模量，k₃₁和

分别为压电材料的机电耦合系数和许用压应力，L为压电振子f的悬臂长度。The piezoelectric vibrator f is formed by bonding the substrate f1 and the piezoelectric sheet f2. The substrate f1 is installed close to the gasket g. The free end of the piezoelectric vibrator f is against the splint i, but there is no interaction between the piezoelectric vibrator f and the splint i. Force, the piezoelectric vibrator f has a straight structure before and after installation; the allowable deformation of the free end of the piezoelectric vibrator f is

Among them: B=1-α+αβ, A=α ⁴ (1-β) ² -4α ³ (1-β)+6α ² (1-β)-4α(1-β)+1,

α=h _m /H, β=E _m /E _p , h _m is the thickness of the substrate f1, H is the total thickness of the piezoelectric vibrator f, E _m and E _p are the Young's of the materials of the substrate f1 and the piezoelectric sheet f2 respectively Modulus, k ₃₁ and

are the electromechanical coupling coefficient and the allowable compressive stress of the piezoelectric material, respectively, and L is the cantilever length of the piezoelectric vibrator f.

In the non-working state, that is, when there is no vibration in the environment, the piezoelectric vibrator f and the reed h are in the original straight state without bending deformation; when there is vertical vibration in the environment, the inertia block j drives the splint i up and down Vibration; when there is vibration in other directions in the environment, the inertia block j drives the splint i to swing; any position change of the splint i will change the contact point between the splint i and the piezoelectric vibrator f, thereby changing the deformation of the piezoelectric vibrator f and its Stress distribution state on the piezoelectric sheet f2, during the change process of the stress distribution state on the piezoelectric sheet f2, the mechanical energy will be converted into electrical energy; When the end is close to but not in contact with the limit ring z, the repulsive force between the fixed magnet piece x and the moving magnet piece y or the repulsive force between the suspended magnet d and the suspended magnet k has a buffering effect; when the free end of the piezoelectric vibrator f and When the limit ring z is in contact, the deformation of the free end of the piezoelectric vibrator f is less than its allowable value, thereby ensuring that the maximum compressive stress on the piezoelectric piece f2 is less than its allowable value.

In the present invention, the deformation characteristics of the piezoelectric vibrator f are jointly determined by the mass of the inertia block j, the structural scale of the reed h, and the structural scale of the splint i, so the fundamental frequency of the energy harvester is easily adjusted through the above-mentioned elements and parameters, thereby Realize matching with the pitching vibration frequency of the ship; because the fundamental frequency of the piezoelectric vibrator f itself is much higher than the pitching vibration frequency of the ship, the piezoelectric vibrator f always works in the first-order mode, and the power generation effect is better; in addition, the piezoelectric vibrator The vibrator f only bears the one-way excitation of the inertial block j and the splint i during operation, and the excitation direction makes the piezoelectric sheet f2 bear the compressive stress. There will be tensile stress or the tensile stress is small, so the reliability is high.

Claims (1)

1. A swing type multi-directional piezoelectric energy harvester, characterized in that: the end of the side wall of the housing is equipped with a loam cake, and the loam cake is equipped with a fixed magnetic piece and a limit ring, and the material of the limit ring is rubber; The bottom wall of the housing is equipped with a circuit board and a suspension magnet, the suspension magnet is circular; the circuit board is equipped with an energy conversion circuit and a signal transmission system; the left side wall of the housing is provided with a left upper boss and a left lower boss, The right side wall of the body is provided with a right upper boss and a right lower boss; the two ends of the partition are installed on the left and right lower boss respectively, and a through hole is arranged on the partition and a limit ring is installed; the left upper boss and the right upper Two piezoelectric vibrators and two gaskets are installed on the bosses through the pressure plate, and the two gaskets are sandwiched between the fixed ends of the two piezoelectric vibrators; the fixed sections at both ends of the reed are respectively crimped on the left upper boss and the Between the two gaskets on the upper right boss, a wide spring is connected between the fixed sections at both ends of the reed through two narrow springs; the wide spring is equipped with two splints, a moving magnetic piece and an inertia block, and two splints Symmetrically clamped on the upper and lower sides of the wide spring, the moving magnet is placed above the wide spring and installed opposite to the same pole of the fixed magnet, the diameter of the moving magnet is smaller than the diameter of the fixed magnet; the inertia block is a T-shaped structure, the diameter of the inertia block is The smaller end is fixed on the splint under the wide spring, and the larger diameter end is equipped with a suspended magnet. The suspended magnet is installed opposite to the same-sex magnetic pole of the suspension magnet. The diameter of the suspended magnet is smaller than the diameter of the suspension magnet; the piezoelectric vibrator It is formed by bonding the substrate and the piezoelectric sheet, the substrate is installed close to the gasket, and the free end of the piezoelectric vibrator is against the splint, but there is no interaction force between the two; the piezoelectric vibrator is a straight structure before and after installation.

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