Multiple electromagnetic negative stiffness low-frequency vibration absorption system using soft material and frequency extension method
The low-frequency vibration absorption system with multiple electromagnetic negative stiffness controlled by soft materials and an air pump system solves the problem of poor low-frequency suppression effect of existing vibration absorbers, and achieves frequency bandwidth expansion and vibration suppression effect improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTHWEST JIAOTONG UNIV
- Filing Date
- 2023-12-11
- Publication Date
- 2026-07-21
AI Technical Summary
Existing vibration absorbers have a narrow tuning frequency range and are not ideal in suppressing low-frequency vibrations.
The low-frequency vibration absorption system using multiple electromagnetic negative stiffnesses of soft materials controls the supporting force and shape of the polymer-based soft material structure through an air pump system, allowing the electromagnetic stiffness within the electromagnetic vibration absorption subsystem to switch between negative and positive stiffness ranges. The overall stiffness is controlled by the current of the excitation coil, and combined with the principle of multiple dynamic vibration absorption, the operating frequency bandwidth is broadened.
It effectively suppresses low-frequency vibrations, broadens the operating frequency bandwidth of the electromagnetic vibration absorption subsystem, and improves the effective range of vibration suppression.
Smart Images
Figure CN117628096B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a low-frequency vibration absorption system with multiple electromagnetic negative stiffness using soft materials and its frequency extension method. Background Technology
[0002] Vibration is an unavoidable phenomenon during the operation of all types of rotating machinery. During operation, the core component of rotating machinery—the rotor—will vibrate due to imbalance, misalignment, rubbing, and other reasons. Strong vibrations can adversely affect the stable operation of rotating machinery, and in severe cases, can lead to shutdowns or even major accidents resulting in machine failure and loss of life. Therefore, reducing rotor vibration is of great significance for improving equipment reliability and ensuring the safe and stable operation of machinery.
[0003] The first dynamic vibration absorber appeared in 1909. Compared with vibration isolators, the advantages of dynamic vibration absorbers are that they can achieve small and lightweight design, cause little damage to the original structure of the controlled object, and at the same time have excellent vibration damping performance. They have a wide range of applications in mechanical vibration suppression, building vibration control and other fields.
[0004] Existing vibration absorbers have a narrow tuning frequency range and a high characteristic frequency, resulting in insufficient suppression of low-frequency vibrations. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing systems by providing a low-frequency vibration absorption system and frequency expansion method using soft materials with multiple electromagnetic negative stiffness. This system can reduce the total stiffness of the electromagnetic vibration absorption subsystem to achieve low-frequency vibration reduction, and expand the effective frequency band through positive and negative stiffness switching and multiple vibration absorption principles, thereby overcoming the shortcomings of insufficient low-frequency vibration reduction performance of existing dynamic vibration absorbers.
[0006] The technical solution to achieve the above objectives is:
[0007] One of the present inventions is a multi-electromagnetic negative stiffness low-frequency vibration absorption system using soft materials, comprising: a controlled main vibration system, an electromagnetic vibration absorption subsystem, and an air pump system. The lower end of the controlled main vibration system is connected to a spring on one side and a damper on the other side. The other ends of the spring and the damper are grounded. The upper end of the controlled main vibration system is provided with an electromagnetic vibration absorption subsystem, and the electromagnetic vibration absorption subsystem is externally connected to an air pump system.
[0008] Preferably, the electromagnetic oscillator system includes: an outer frame stator, a first moving core, and a second moving core, wherein the first moving core and the second moving core are disposed within the outer frame stator, and the first moving core and the second moving core are connected by a polymer-based soft material support structure.
[0009] Preferably, an excitation coil is wound around the outer side of the first moving core and the second moving core. The upper end of the first moving core is connected to the upper end of the outer frame stator through a first mechanical spring element, and the lower end of the second moving core is connected to the lower end of the outer frame stator through a second mechanical spring element.
[0010] Preferably, the first and second moving cores each have two pairs of moving teeth on their outer sides; the outer frame stator has stator teeth corresponding to the moving teeth on its inner side.
[0011] Preferably, a gap is left between the moving teeth and the stator teeth.
[0012] Preferably, the outer frame stator, the first mover core, and the second mover core are made of magnetically conductive material.
[0013] Preferably, the polymer-based soft material support structure is internally designed as a cavity structure, which is externally connected to the air pump system. The air pump system includes a main air pump device and a hose, and the polymer-based soft material support structure is connected to the main air pump device through the hose.
[0014] The second invention relates to a frequency expansion method for a low-frequency vibration absorption system employing multiple electromagnetic negative stiffnesses using soft materials, comprising:
[0015] Step S1: The air pump system controls the supporting force and shape of the internal cavity of the polymer soft material structure, so that the electromagnetic stiffness between the first moving core, the second moving core and the outer frame stator in the electromagnetic vibration absorption subsystem can switch between the negative stiffness range and the positive stiffness range.
[0016] Step S2: By introducing the polymer-like soft material support structure, the electromagnetic vibration absorption subsystem is transformed into a multi-dynamic vibration absorption system, thereby broadening the operating frequency bandwidth of the electromagnetic vibration absorption subsystem.
[0017] Step S3: Control the overall stiffness of the electromagnetic oscillator system by controlling the magnitude of the current in the excitation coil.
[0018] The beneficial effects of this invention are as follows: This invention controls the supporting force and shape of the internal cavity of the polymer-based soft material structure through an air pump system, allowing the electromagnetic stiffness between the first mover core, the second mover core, and the outer frame stator within the electromagnetic vibration absorber system to switch between negative and positive stiffness ranges. In the negative stiffness range, increasing the current flowing through the excitation coil reduces the total stiffness of the electromagnetic vibration absorber system, thereby lowering the natural frequency of the electromagnetic vibration absorber and effectively suppressing low-frequency vibrations. In the positive stiffness range, increasing the current flowing through the excitation coil increases the total stiffness of the electromagnetic vibration absorber system, thereby increasing the natural frequency of the electromagnetic vibration absorber and thus extending the effective range of vibration suppression. Furthermore, this invention introduces a polymer-based soft material support structure, transforming the electromagnetic vibration absorber system into a multi-dynamic vibration absorption system, further broadening the operating frequency bandwidth of this electromagnetic vibration absorber system. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the low-frequency vibration absorption system using soft materials with multiple electromagnetic negative stiffness according to the present invention.
[0020] Figure 2 This is a schematic diagram of the specific structure of the electromagnetic vibration absorption subsystem in this invention;
[0021] Figure 3 This is a schematic diagram of the electromagnetic vibration absorber system in this invention when the axial displacement is 0.
[0022] Figure 4 This is a schematic diagram of the initial position of the electromagnetic vibration absorption subsystem in this invention corresponding to the negative stiffness range;
[0023] Figure 5 This is a schematic diagram of the energized state of the excitation coil in this invention;
[0024] Figure 6 This is a schematic diagram of the negative stiffness range when the excitation coil is energized in this invention;
[0025] Figure 7 This is a schematic diagram illustrating the principle of negative stiffness when different currents are applied to the excitation coil in this invention.
[0026] Figure 8 This is a simplified diagram of the dynamic model of the low-frequency vibration absorption system with multiple electromagnetic negative stiffness using soft materials in this invention.
[0027] Figure 9 This is a schematic diagram of the external air pump system for the polymer-based soft material support structure in this invention.
[0028] Figure 10 This is a schematic diagram illustrating the principle of adjusting the positive and negative stiffness of the external air pump system of the polymer soft material support structure in this invention.
[0029] Figure 11This is a flowchart of the frequency expansion method of the low-frequency vibration absorption system with multiple electromagnetic negative stiffness using soft materials, as described in this invention.
[0030] In the diagram: 1. Controlled main vibration system; 2. Spring; 3. Damper; 4. Electromagnetic oscillator system; 5. Outer frame stator; 61. First mover core; 62. Second mover core; 7. Excitation coil; 8. Polymer-based soft material support structure; 91. First mechanical spring element; 92. Second mechanical spring element; 10. Mover tooth; 11. Stator tooth; 12. Air pump system; 13. Main air pump device; 14. Hose. Detailed Implementation
[0031] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0032] The invention will now be further described with reference to the accompanying drawings.
[0033] like Figure 1 As shown, a multi-electromagnetic negative stiffness low-frequency vibration absorption system using soft materials includes: a controlled main vibration system 1, an electromagnetic vibration absorption subsystem 4, and an air pump system 12. A spring 2 is connected to one side of the lower end of the controlled main vibration system 1, and a damper 3 is connected to the other side. The other ends of the spring 2 and the damper 3 are grounded. An electromagnetic vibration absorption subsystem 4 is provided at the upper end of the controlled main vibration system 1, and an air pump system 12 is connected to the electromagnetic vibration absorption subsystem 4.
[0034] like Figure 2 As shown, the electromagnetic oscillator system 4 includes: an outer frame stator 5, a first moving core 61 and a second moving core 62. The first moving core 61 and the second moving core 62 are disposed inside the outer frame stator 5, and the first moving core 61 and the second moving core 62 are connected by a polymer-based soft material support structure 8.
[0035] Preferably, an excitation coil 7 is wound around the outer side of the first moving core 61 and the second moving core 62. The upper end of the first moving core 61 is connected to the upper end of the outer frame stator 5 through the first mechanical spring element 91, and the lower end of the second moving core 62 is connected to the lower end of the outer frame stator 5 through the second mechanical spring element 92.
[0036] Preferably, the first moving core 61 and the second moving core 62 are each provided with two pairs of moving teeth 10 on their outer sides; the outer frame stator 5 is provided with stator teeth 11 corresponding to the moving teeth 10 on its inner side.
[0037] Preferably, a gap is left between the moving tooth 10 and the stator tooth 11 to ensure the relative movement between the outer frame stator 5 and the first moving core 61 and the second moving core 62.
[0038] Preferably, the polymer-based soft material support structure 8 is designed as a cavity structure, which is connected to an air pump system 12. By adjusting the air pressure inside the cavity, the relative positions of the first mover core 61 and the second mover core 62 with the outer frame stator 5 can be adjusted, thereby adjusting the stiffness range of the electromagnetic vibration absorption subsystem 4.
[0039] like Figure 3 As shown, assuming that the electromagnetic oscillator system 4 is not affected by gravity, the stator teeth 11 on the outer frame stator 5 are aligned one-to-one with the moving teeth 10 on the first moving core 61 and the second moving core 62. It is stipulated that at this time, the axial displacement between the first moving core 61 and the second moving core 62 and the outer frame stator 5 is 0, and no axial displacement occurs between the first moving core 61 and the second moving core 62 and the outer frame stator 5. At this time, the length of the first mechanical spring element 91 is equal to the length of the second mechanical spring element 92, that is, L1 = L2.
[0040] like Figure 2 As shown, if the electromagnetic oscillator system 4 considers weight, due to the gravity acting on the first moving core 61 and the second moving core 62, axial movement will occur. At this time, the first mechanical spring element 91 and the second mechanical spring element 92 undergo static deformation. The first mechanical spring element 91 is stretched, i.e., K1 is stretched, and the second mechanical spring element 92 is compressed, i.e., K2 is compressed. At this time, the length of K1 is L1(2), and the length of K2 is L2(2). At this time, L1(2)>L2(2); Figure 4 As shown, when the excitation coil 7 is energized, a magnetic field is generated around the excitation coil 7. The outer frame stator 5, the first moving core 61, and the second moving core 62 are made of magnetically conductive materials. Since there is a certain gap between the stator teeth 10 on the outer frame stator 5 and the moving teeth 11 on the first moving core 61 and the second moving core 62, and because the air magnetic resistance is too large, the adjacent moving teeth 10 and stator teeth 11 will attract each other due to the magnetic field. The axial displacement of the first moving core 61 and the second moving core 62 relative to the outer frame stator 5 is a. The electromagnetic stiffness generated by the electromagnetic oscillator system 4 is negative stiffness, and the electromagnetic oscillator system 4 is located within the negative stiffness range.
[0041] like Figure 5As shown, when current is passed through the excitation coil 7, relative displacement occurs between the adjacent stator teeth 10 and the mover teeth 11, and they no longer correspond one by one. Therefore, the first mover iron core 61 and the second mover iron core 62 will generate downward axial movement. At this time, the first mechanical spring element 91 is further stretched, that is, K1 is further stretched, and the second mechanical spring element 92 is further compressed, that is, K2 is further compressed. At this time, the length of K1 is L1(3), the length of K2 is L2(3), L1(3)>L2(3), L1(3)>L1(2), L2(2)>L2(3); as Figure 6 shown, at this time, the axial displacements of the first mover iron core 61 and the second mover iron core 62 relative to the outer frame stator 5 are b, and the electromagnetic stiffness generated by the electromagnetic vibration absorber system 4 is negative stiffness.
[0042] As Figure 7 shown, the electromagnetic stiffness law of the electromagnetic vibration absorber system 4 is negative stiffness within a certain interval (X1, X2). Therefore, by reasonably setting the magnetic circuit tooth layer parameters inside the electromagnetic vibration absorber system 4, the axial displacements of the inner and outer frame stators 5, the first mover iron core 61, and the second mover iron core 62 of the electromagnetic vibration absorber system 4 occur within this interval, and the electromagnetic stiffness is negative stiffness. At this time, the total stiffness K of the electromagnetic vibration absorber system 4 = Kb - Ke, where Kb is the stiffness of the first mechanical spring element 91 and the second mechanical spring element 92, and Ke is the electromagnetic stiffness. When current is passed through the excitation coil 7, electromagnetic negative stiffness is generated, and the total stiffness of the electromagnetic vibration absorber system 4 decreases. Therefore, the natural frequency decreases, thereby effectively suppressing low-frequency vibration.
[0043] As Figure 7 shown, the current magnitudes I1 < I2 < I3, and the absolute values of the electromagnetic force and stiffness both increase with the increase of the current. Therefore, the total stiffness of the electromagnetic vibration absorber system 4 can also be controlled by controlling the current magnitude of the excitation coil 7, and the vibration suppression frequency band can be frequency-expanded.
[0044] As Figure 8 shown, a polymer soft material support structure 8 is introduced, M P , K P , C P are the mass, spring 2 stiffness, and damper 3 of the controlled main vibration system 1; m1, K1, C1 are the mass, spring stiffness of the first mover iron core 61, and damping; m2, K2, C2 are the mass, spring stiffness inside the second mover iron core 62, and damping; K3, C3 are the spring stiffness and damping of the polymer soft material support structure 8. The introduction of the polymer soft material support structure 8 makes this electromagnetic vibration absorber system 4 become a multiple dynamic vibration absorber system m1, K1, C1 and m2, K2, C2 composed of two mass-spring-damper systems, broadening the working frequency bandwidth of this electromagnetic vibration absorber system 4.
[0045] As Figure 9 , 10 As shown, the polymer-based soft material support structure 8 has an internal cavity structure, which is externally connected to an air pump system 12. The air pump system 12 includes a main air pump device 13 and a hose 14. The polymer-based soft material support structure 8 is connected to the main air pump device 13 through the hose 14. By adjusting the air pressure inside the cavity of the polymer-based soft material support structure 8, the relative positions of the first mover core 61 and the second mover core 62 with the outer frame stator 5 can be adjusted, thereby adjusting the stiffness range of the electromagnetic vibration absorption subsystem 4.
[0046] In this embodiment, if the air pump system 12 is operating, the main air pump device 13 injects air into the internal cavity structure of the polymer-like soft material support structure 8 through the hose 14. The internal pressure of the cavity increases, causing the polymer-like soft material support structure 8 to expand under pressure. This results in axial movement of the first moving core 61 and the second moving core 62. The first moving core 61 experiences an upward axial movement, while the second moving core 62 experiences a downward axial movement. At this time, the change in relative displacement between the moving teeth 10 and the corresponding stator teeth 11 on the first moving core 61 is as follows: Figure 10 As shown in section “A”, the stiffness of the electromagnetic vibration absorption subsystem 4 can be adjusted (positive / negative and magnitude); similarly, the change in relative displacement between the moving tooth 10 and the corresponding stator tooth 11 on the second moving core 62 is as follows: Figure 10 As shown in section “B”, the stiffness of the electromagnetic vibration absorption subsystem 4 can be adjusted in terms of positive and negative values and magnitude, thereby realizing the frequency expansion of the electromagnetic vibration absorption subsystem.
[0047] like Figure 11 As shown, the frequency expansion method for a low-frequency vibration absorption system with multiple electromagnetic negative stiffness using soft materials includes:
[0048] Step S1: The air pump system 12 controls the supporting force and shape of the internal cavity of the polymer soft material structure 8, so that the electromagnetic stiffness between the first moving core 61, the second moving core 62 and the outer frame stator 5 in the electromagnetic vibration absorption subsystem 4 can switch between the negative stiffness range and the positive stiffness range, thereby expanding the effective range of vibration suppression.
[0049] In step S2, by introducing the polymer-like soft material support structure 8, the electromagnetic vibration absorption subsystem 4 is transformed into a multi-dynamic vibration absorption system, further broadening the operating frequency bandwidth of this electromagnetic vibration absorption subsystem 4.
[0050] Step S3: By controlling the magnitude of the current in the excitation coil 7, the overall stiffness of the frequency electromagnetic oscillator system 4 can be controlled, thereby extending the vibration suppression frequency band.
[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A low-frequency vibration absorption system employing multiple electromagnetic negative stiffnesses using soft materials, characterized in that, include: The controlled main vibration system (1), the electromagnetic vibration absorption subsystem (4) and the air pump system (12) are provided. The lower end of the controlled main vibration system (1) is connected to a spring (2) on one side and a damper (3) on the other side. The other end of the spring (2) and the damper (3) are grounded. The upper end of the controlled main vibration system (1) is provided with an electromagnetic vibration absorption subsystem (4) and the air pump system (12) is connected to the electromagnetic vibration absorption subsystem (4). The electromagnetic vibration absorption subsystem (4) includes: an outer frame stator (5), a first moving core (61) and a second moving core (62), the first moving core (61) and the second moving core (62) are disposed in the outer frame stator (5), and the first moving core (61) and the second moving core (62) are connected by a polymer soft material support structure (8). The polymer soft material support structure (8) is designed as a cavity structure, and the air pump system (12) is connected to the outside. The air pump system (12) includes a main air pump device (13) and a hose (14). The polymer soft material support structure (8) is connected to the main air pump device (13) through the hose (14).
2. The low-frequency vibration absorption system using soft materials with multiple electromagnetic negative stiffness according to claim 1, characterized in that, An excitation coil (7) is wound around the outside of the first moving core (61) and the second moving core (62). The upper end of the first moving core (61) is connected to the upper end of the outer frame stator (5) through the first mechanical spring element (91), and the lower end of the second moving core (62) is connected to the lower end of the outer frame stator (5) through the second mechanical spring element (92).
3. The low-frequency vibration absorption system using soft materials with multiple electromagnetic negative stiffness according to claim 1, characterized in that, The first moving core (61) and the second moving core (62) each have two pairs of moving teeth (10) on their outer sides; the outer frame stator (5) has stator teeth (11) corresponding to the moving teeth (10) on its inner side.
4. The low-frequency vibration absorption system using soft materials with multiple electromagnetic negative stiffness according to claim 3, characterized in that, There is a gap between the moving tooth (10) and the stator tooth (11).
5. The low-frequency vibration absorption system using soft materials with multiple electromagnetic negative stiffness according to claim 3, characterized in that, The outer frame stator (5), the first moving core (61), and the second moving core (62) are made of magnetically conductive material.
6. The frequency expansion method based on the low-frequency vibration absorption system with multiple electromagnetic negative stiffness using soft materials as described in claim 2, characterized in that, include: Step S1: The air pump system (12) controls the supporting force and shape of the internal cavity of the polymer soft material support structure (8), so that the electromagnetic stiffness between the first moving core (61), the second moving core (62) and the outer frame stator (5) in the electromagnetic vibration absorption system (4) can switch between the negative stiffness range and the positive stiffness range. Step S2, by introducing the polymer-like soft material support structure (8), the electromagnetic vibration absorption subsystem (4) is transformed into a multi-dynamic vibration absorption system, thereby broadening the operating frequency bandwidth of the electromagnetic vibration absorption subsystem (4); Step S3: Control the total stiffness of the electromagnetic oscillator system (4) by controlling the current magnitude of the excitation coil (7).