Axial eddy current damping energy harvester based on positive piezoelectric effect

Abstract

The application belongs to the field of structural vibration control, and particularly relates to an axial eddy current damping energy harvester based on positive piezoelectric effect. The technology comprises a central shaft, a cylinder sleeve, an eddy current energy dissipation assembly, a first piezoelectric energy harvesting assembly and a second piezoelectric energy harvesting assembly. The cylinder sleeve is axially provided with a mounting cavity, and the eddy current energy dissipation assembly is arranged in the mounting cavity. The eddy current energy dissipation assembly is axially provided with a through hole, and the central shaft is independently arranged in the through hole. The left end of the central shaft extends out of the cylinder sleeve to be connected to a structure to be damped. The first piezoelectric energy harvesting assembly is arranged on the outer extension of the central shaft. The second piezoelectric energy harvesting assembly is arranged at the right end in the mounting cavity, and the right end of the central shaft is tightly attached to the piezoelectric energy assembly. The overall friction of the axial damper is reduced, the durability of the overall structure is improved, the damper is more sensitive, the energy dissipation and vibration reduction capacity is improved, the application range is wider, the stability and accuracy of the equipment are improved.

Description

Technical Field

[0001] This invention belongs to the field of structural vibration control, and in particular relates to an axial eddy current damping energy trap based on the positive piezoelectric effect. Background Technology

[0002] Traditional axial dampers are mostly oil dampers, but the sealing and durability of oil dampers require regular maintenance and inspection, which increases maintenance costs. Furthermore, the presence of seals results in high friction within the damper, making oil dampers less suitable for environments with frequent operation and requiring sensitive start-up. In addition, traditional dampers often experience direct friction and collisions between components during operation, reducing their lifespan. Moreover, the vibrational energy transmitted to the damper is usually dissipated directly without any means of energy harvesting or utilization, resulting in significant energy waste.

[0003] To address this, Chinese patent CN218000241U discloses an eddy current damper. This damper consists of a housing, a movable guide rod, and a magnetic assembly forming an eddy current damping system. When the structure to be damped vibrates, the movable guide rod is forced to undergo axial tensile and compressive motion, resulting in relative displacement with the magnetic assembly to cut magnetic field lines and generate induced eddy currents. These induced eddy currents produce a magnetic field opposite to the original magnetic field, thus generating a damping force that hinders the relative motion between the movable guide rod and the original magnetic field. Simultaneously, the induced eddy currents generated within the movable guide rod are continuously dissipated into the surrounding environment as heat, thereby dissipating energy and reducing vibration in the structure to be damped. Furthermore, a guide assembly and a wind-resistant assembly ensure smooth movement. However, this patented structure has a limited applicability and generates energy dissipation, resulting in waste.

[0004] Therefore, there is a need for an axial eddy current damped energy trap that combines the functions of a damper and an energy trap while having a wide range of applications, in order to overcome the above-mentioned shortcomings. Summary of the Invention

[0005] The purpose of this invention is to provide an axial eddy current damping energy harvester based on the positive piezoelectric effect, which overcomes the technical defects of existing dampers, such as large overall friction, poor durability, insufficient sensitivity, lack of vibration energy harvesting and utilization, and limited applicability.

[0006] The axial eddy current damping energy trap based on the positive piezoelectric effect includes a central shaft, a cylinder liner, an eddy current energy dissipation component, a first piezoelectric energy trapping component, and a second piezoelectric energy trapping component. The cylinder liner has an axially oriented mounting cavity, in which the eddy current energy dissipation component is disposed. The eddy current energy dissipation component has an axially oriented through hole, and the central shaft is independently mounted in the through hole. The left end of the central shaft extends out of the cylinder liner to connect to the structure to be damped. The first piezoelectric energy trapping component is fitted onto the extended portion of the central shaft, and the second piezoelectric energy trapping component is disposed at the right end within the mounting cavity. The right end of the central shaft is in close contact with the piezoelectric energy trapping component.

[0007] Furthermore, the first piezoelectric energy harvesting assembly includes a left spring and a first piezoelectric component. The first piezoelectric component is independently sleeved on the extended portion of the central shaft. The left spring is sleeved on the first piezoelectric component, forming a limiting surface at the left end of the central shaft. The two ends of the left spring are fixedly connected to the limiting surface and the left end of the cylinder liner, respectively. The left end of the first piezoelectric component is fixedly connected to the limiting surface, and the right end of the first piezoelectric component is in close contact with the left end of the cylinder liner.

[0008] Furthermore, the first piezoelectric component is composed of multiple stacked annular piezoelectric elements.

[0009] Furthermore, a baffle is fitted on the central shaft on the right side of the limiting surface, and the left spring and the first piezoelectric component are disposed between the left end face of the baffle and the cylinder liner, and the left end of the left spring and the left end of the first piezoelectric component are fixedly connected to the right side surface of the baffle.

[0010] Furthermore, the second piezoelectric energy harvesting assembly includes a right spring and a second piezoelectric assembly passing through the center of the right spring. The two ends of the right spring are fixedly connected to the right end of the central shaft and the right end of the mounting cavity, respectively. The left end of the second piezoelectric assembly is in close contact with the right end of the central shaft, and the right end of the second piezoelectric assembly is fixedly connected to the right end face of the mounting cavity.

[0011] Furthermore, the second piezoelectric component is composed of multiple cylindrical piezoelectric elements stacked together.

[0012] Furthermore, the eddy current energy dissipation component includes a conductor, multiple permanent magnets, and multiple magnetic rings. The conductor is fixed inside the mounting cavity, the permanent magnets are fixed in the central holes of the conductor, and magnetic rings are arranged between two adjacent permanent magnets. The through hole is formed at the center of the permanent magnets and the magnetic rings.

[0013] Furthermore, the left and right ends of the conductor extend to the left and right end faces of the mounting cavity.

[0014] Furthermore, a linear bearing is provided between the left end of the cylinder liner and the central shaft, and a guide bearing is provided between the conductor and the central shaft.

[0015] Furthermore, a left-end connector is provided at the left end of the central shaft, and a right-end connector is connected to the right end of the cylinder liner.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. By using a frictionless, non-contact eddy current damping system, the overall friction of the axial damper is reduced, the durability of the overall structure is improved, and the damper is made more sensitive.

[0018] 2. By adding two piezoelectric structures, the original single damper is transformed into a composite damper, which enhances the energy dissipation and vibration reduction capabilities and has a wider range of applications.

[0019] 3. By absorbing and consuming the energy generated by system vibration through the piezoelectric energy-harvesting structure, the stability and accuracy of the equipment are improved. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention;

[0021] Figure 2 A schematic diagram of generating electrical energy for the first or second piezoelectric component.

[0022] The components in the diagram are named as follows: 1. Central shaft; 2. Baffle; 3. Left spring; 4. First piezoelectric assembly; 5. Linear bearing; 6. Cylinder liner; 7. Conductor; 8. Permanent magnet; 9. Magnetic ring; 10. Guide bearing; 11. Right spring; 12. Second piezoelectric assembly; 13. Right end connector; 14. Left end connector. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0024] like Figure 1 and Figure 2 As shown, an axial eddy current damping energy trap based on the positive piezoelectric effect includes a central shaft 1, a cylinder liner 6, an eddy current energy dissipation component, a first piezoelectric energy trapping component, and a second piezoelectric energy trapping component. The cylinder liner 6 has an axially formed mounting cavity, in which the eddy current energy dissipation component is disposed. The eddy current energy dissipation component has an axially formed through hole. The central shaft 1 is independently mounted in the through hole and does not contact the surface of the through hole. The left end of the central shaft 1 extends out of the cylinder liner 6 to connect to the structure to be damped. The first piezoelectric energy trapping component is sleeved on the extended part of the central shaft 1, and the second piezoelectric energy trapping component is disposed at the right end in the mounting cavity. The right end of the central shaft 1 is in close contact with the piezoelectric energy trapping component.

[0025] In the aforementioned axial eddy current damping energy trap, the eddy current energy dissipation component generates induced eddy currents when the central shaft 1 and cylinder liner 6 cut magnetic field lines during relative motion. These induced eddy currents generate a magnetic field opposite to the original magnetic field, thus producing a damping force that opposes changes in magnetic flux. This converts the kinetic energy of the structure to be damped into its own heat energy for dissipation, thereby achieving energy dissipation and vibration reduction. Simultaneously, the cylinder liner 6 forces the first and second piezoelectric energy trapping components to deform and vibrate, causing the piezoelectric materials in these components to convert the captured vibrational energy into electrical energy due to the positive piezoelectric effect. This electrical energy is then used to provide a counterforce, thereby achieving the purpose of energy dissipation and vibration reduction. Therefore, the axial eddy current damper described in this example effectively reduces the overall friction of the axial damper through a frictionless, non-contact eddy current damping system, improving its overall durability and making it more sensitive. Simultaneously, by adding two piezoelectric energy harvesting components, the original single damper is transformed into a composite damper, enhancing its energy dissipation and vibration reduction capabilities. Furthermore, the piezoelectric energy harvesting components further absorb and dissipate the energy generated by the vibration of the structure system to be damped, improving the stability and accuracy of the equipment compared to a single damper.

[0026] like Figure 1 As shown, in this example, the first piezoelectric energy harvesting assembly includes a left spring 3 and a first piezoelectric assembly 4. The first piezoelectric assembly 4 is independently sleeved on the extended part of the central shaft 1. The left spring 3 is sleeved on the first piezoelectric assembly 4, and a limiting surface is formed at the left end of the central shaft 1. The two ends of the left spring 3 are fixedly connected to the limiting surface and the left end of the cylinder liner 6, respectively. The left ends of the first piezoelectric assembly 4 are fixedly connected to the limiting surface, and the right end of the first piezoelectric assembly 4 is in close contact with the left end of the cylinder liner 6.

[0027] When the axial eddy current piezoelectric damping energy harvester is forced into axial tensile and compressive motion during use, that is, when the central shaft 1 and the cylinder liner 6 move relative to each other, if the cylinder liner 6 compresses the first piezoelectric component 4 in the first piezoelectric energy harvesting assembly and causes it to deform, the first piezoelectric component 4 will convert the captured vibration energy into electrical energy due to the positive piezoelectric effect. At the same time, the left spring 3, being compressed and deformed, will provide a counter-force, thereby achieving energy dissipation and vibration reduction. If there is a pull-out force between the cylinder liner 6 and the left spring 3, the elastic restoring force of the left spring 3, after deformation, will be used to provide a counter-force, which can also achieve the purpose of energy dissipation and vibration reduction. The setting of the left spring 3 can also help control the deformation of the first piezoelectric component 4 when it is compressed, avoiding damage to the first piezoelectric component 4 due to excessive deformation.

[0028] In this example, the first piezoelectric component 4 is preferably composed of multiple stacked annular piezoelectric elements, which can accumulate a sufficient amount of deformation, that is, capture more vibration energy to convert it into electrical energy.

[0029] In this embodiment of the invention, a baffle 2 is fitted onto the central shaft 1 on the right side of the limiting surface. The left spring 3 and the first piezoelectric component 4 are disposed between the baffle 2 and the left end face of the cylinder liner 6, and the left end of the left spring 3 and the left end of the first piezoelectric component 4 are both fixedly connected to the right side surface of the baffle 2. This structure facilitates the limiting installation of the left spring 3 and the first piezoelectric component 4.

[0030] like Figure 1 As shown, the eddy current energy dissipation component in this example includes a conductor 7, multiple permanent magnets 8, and multiple magnetic rings 9. The conductor 7 is fixed in the mounting cavity, and the left and right ends of the conductor 7 extend to the left and right end faces of the mounting cavity. The permanent magnets 8 are fixed in the central hole of the conductor 7. Magnetic rings 9 are arranged between two adjacent permanent magnets 8, and the through hole is formed in the center of the permanent magnets 8 and the magnetic rings 9.

[0031] The permanent magnet 8 is used to form a magnetic field with a large axial range to increase the eddy current damping force generated when the central shaft 1 moves. Adjacent permanent magnets 8 are separated axially by a magnetically conductive ring 9 to guide the magnetic field and enhance its strength. Optionally, the magnetically conductive ring 9 is made of a magnetically conductive material. Optionally, the magnetically conductive material is a magnetic field concentrator or an iron core, and the magnetically conductive material is one of silicon steel sheets, ferrite, and non-magnetically conductive materials. During use, the damping magnitude can be adjusted by changing the number and size of the permanent magnets 8, the gap between the permanent magnets 8 and the conductor 7, and the axial length of the magnetically conductive ring 9.

[0032] like Figure 1 As shown, in this example, the second piezoelectric energy harvesting assembly includes a right spring 11 and a second piezoelectric assembly 12 passing through the center of the right spring 11. The two ends of the right spring 11 are fixedly connected to the right end of the central shaft 1 and the right end of the mounting cavity, respectively. The left end of the second piezoelectric assembly 12 is in close contact with the right end of the central shaft 1, and the right end of the second piezoelectric assembly 12 is fixedly connected to the right end face of the mounting cavity.

[0033] When the axial eddy current piezoelectric damping energy harvester is forced into axial tensile and compressive motion during use, that is, when the central shaft 1 and the cylinder liner 6 move relative to each other, if the central shaft 1 compresses the second piezoelectric component 12 in the second piezoelectric energy harvesting assembly and causes it to deform, the second piezoelectric component 12 will convert the captured vibration energy into electrical energy due to the positive piezoelectric effect. At the same time, the right spring 11, which is compressed and deformed, will provide a counter-force, thereby achieving energy dissipation and vibration reduction. If there is a pull-out force between the cylinder liner 6 and the right spring 11, the elastic restoring force of the right spring 11 will be used to provide a counter-force, which can also achieve the purpose of energy dissipation and vibration reduction. The setting of the right spring 11 can also help control the deformation of the second piezoelectric component 12 when it is compressed, and avoid damage to the second piezoelectric component 12 due to excessive deformation.

[0034] Preferably, the second piezoelectric component 12 is composed of multiple cylindrical piezoelectric elements stacked together, thereby accumulating a sufficient amount of deformation, that is, capturing more vibration energy to convert it into electrical energy.

[0035] See appendix Figure 1 A linear bearing 5 is provided between the left end of the cylinder liner 6 and the central shaft 1, and a guide bearing 10 is provided between the conductor 7 and the central shaft 1. The linear bearing 5 and the guide bearing 10 are used to guide the movement of the central shaft 1 and can transform the surface contact between the central shaft 1 and other components into point-to-surface contact, which greatly reduces the friction.

[0036] Preferably, a left-end connector 14 is provided at the left end of the central shaft 1, and a right-end connector 13 is connected to the right end of the cylinder liner 6. In this embodiment, the axial eddy current piezoresistive damper is connected to the structure to be damped via the left-end connector 14 and the right-end connector 13. Optionally, the position, quantity, and structural form of the left-end connector 14 and the right-end connector 13 can be adaptively selected according to the specific operating environment of the axial eddy current piezoresistive damper.

[0037] The principle by which the first piezoelectric component 4 and the second piezoelectric component 12, after being stacked, generate electrical energy is as follows: Figure 2 As shown, the formula for calculating the generated electrical energy E is as follows:

[0038]

[0039] In the formula, n is the number of piezoelectric elements connected in parallel; d 33 ε3 represents the strain constant of the piezoelectric element; F represents the vertical stress acting on the piezoelectric element; A represents the cross-sectional area of ​​the piezoelectric element; h represents the thickness of a single piezoelectric element; ε3 represents the cross-sectional area of ​​the piezoelectric element. T 3 is the dielectric constant.

[0040] In the specific implementation of this embodiment, the damping magnitude can also be adjusted by changing the way the permanent magnet 8 and the conductor 7 are matched. For example, the diameter of the permanent magnet 8 can be increased to increase the magnetic field strength of the magnet. The power generation efficiency can also be increased by changing the combined structure of the annular piezoelectric sheet in the first piezoelectric component 4. For example, the annular piezoelectric sheet can be composed of two piezoelectric rings connected in parallel by wires.

[0041] In summary, the circumferential eddy current damping energy trap described in this embodiment of the invention combines the functions of a damper and an energy trap. When the central shaft 1 and the cylinder liner 6 generate relative motion that cuts magnetic field lines, induced eddy currents are generated. These induced eddy currents produce a magnetic field opposite to the original magnetic field, thereby generating a damping force that opposes changes in magnetic flux. This converts the kinetic energy of the structure to be damped into its own heat energy for dissipation, thus achieving energy dissipation and vibration reduction. Simultaneously, the cylinder liner 6 forces the first and second piezoelectric energy trapping components to deform, compressing the left spring 3, the right spring 12, and the first and second piezoelectric components 4 and 11 inside them. This causes the first and second piezoelectric components 4 and 11 to convert the captured vibration energy into electrical energy due to the positive piezoelectric effect, providing a force in the opposite direction, thereby achieving the purpose of energy dissipation and vibration reduction.

[0042] Therefore, the axial eddy current damper described in this example effectively reduces the overall friction of the axial damper through a frictionless, non-contact eddy current damping system, improving overall durability and making the damper more sensitive. At the same time, by adding two piezoelectric energy harvesting components, the original single damper is transformed into a composite damper, enhancing the energy dissipation and vibration reduction capabilities. In addition, the piezoelectric energy harvesting components further absorb and consume the energy generated by the vibration of the structure system to be damped, improving the stability and accuracy of the equipment compared to a single damper.

[0043] Finally, the damping magnitude of the circumferential eddy current damped energy trap described in this embodiment of the invention is achieved by changing the number and size of the permanent magnets 8 and adjusting the gap between the permanent magnets 8 and the conductor 7; the amount of captured electrical energy can be achieved by changing the number and structural size of the piezoelectric elements used.

Claims

1. An axial eddy current damped energy trap based on the positive piezoelectric effect, characterized in that: The device includes a central shaft (1), a cylinder liner (6), an eddy current energy dissipation component, a first piezoelectric energy harvesting component, and a second piezoelectric energy harvesting component. The cylinder liner (6) has an axially open mounting cavity. An eddy current energy dissipation component is installed in the mounting cavity. The eddy current energy dissipation component has an axially open through hole. The central shaft (1) is independently installed in the through hole. The left end of the central shaft (1) extends out of the cylinder liner (6) to connect to the structure to be damped. The first piezoelectric energy harvesting component is sleeved on the extended part of the central shaft (1). The second piezoelectric energy harvesting component is installed at the right end in the mounting cavity. The right end of the central shaft (1) is in close contact with the second piezoelectric energy harvesting component. The first piezoelectric energy harvesting component includes a left spring (3) and a first piezoelectric component (4). The first piezoelectric component (4) is independently sleeved on the extended part of the central shaft (1). The left spring (3) is sleeved on the first piezoelectric component (4). A limiting surface is formed at the left end of the central shaft (1). The two ends of the left spring (3) are fixedly connected to the limiting surface and the left end of the cylinder liner (6), respectively. The left ends of the first piezoelectric component (4) are fixedly connected to the limiting surface. The right end of the first piezoelectric component (4) is in close contact with the left end of the cylinder liner (6). The second piezoelectric energy harvesting assembly includes a right spring (11) and a second piezoelectric assembly (12) passing through the center of the right spring (11). The two ends of the right spring (11) are fixedly connected to the right end of the central shaft (1) and the right end of the mounting cavity, respectively. The left end of the second piezoelectric assembly (12) is in close contact with the right end of the central shaft (1), and the right end of the second piezoelectric assembly (12) is fixedly connected to the right end face of the mounting cavity.

2. The axial eddy current damped energy trap based on the positive piezoelectric effect according to claim 1, characterized in that: The first piezoelectric component (4) is composed of multiple ring-shaped piezoelectric elements stacked together.

3. The axial eddy current damped energy trap based on the positive piezoelectric effect according to claim 1, characterized in that: A baffle (2) is fitted on the central shaft (1) on the right side of the limiting surface. The left spring (3) and the first piezoelectric component (4) are located between the baffle (2) and the left end face of the cylinder liner (6). The left end of the left spring (3) and the left end of the first piezoelectric component (4) are fixedly connected to the right side surface of the baffle (2).

4. The axial eddy current damped energy trap based on the positive piezoelectric effect according to claim 1, characterized in that: The second piezoelectric component (12) is composed of multiple cylindrical piezoelectric elements stacked together.

5. The axial eddy current damped energy trap based on the positive piezoelectric effect according to claim 1, characterized in that: The eddy current energy dissipation component includes a conductor (7), multiple permanent magnets (8), and multiple magnetic rings (9). The conductor (7) is fixed in the mounting cavity, the permanent magnets (8) are fixed in the central hole of the conductor (7), and magnetic rings (9) are arranged between two adjacent permanent magnets (8). The through hole is formed in the center of the permanent magnets (8) and the magnetic rings (9).

6. The axial eddy current damped energy trap based on the positive piezoelectric effect according to claim 5, characterized in that: The left and right ends of the conductor (7) extend to the left and right end faces of the mounting cavity.

7. The axial eddy current damped energy trap based on the positive piezoelectric effect according to claim 5 or 6, characterized in that: A linear bearing (5) is provided between the left end of the cylinder liner (6) and the central shaft (1), and a guide bearing (10) is provided between the conductor (7) and the central shaft (1).

8. The axial eddy current damped energy trap based on the positive piezoelectric effect according to claim 1, characterized in that: A left end connector (14) is provided at the left end of the central shaft (1), and a right end connector (13) is connected to the right end of the cylinder liner (6).

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